source
stringlengths 745
6.38k
| target
stringlengths 25
28.4k
| lan
stringclasses 23
values |
|---|---|---|
We compare the properties of stellar populations of model galaxies from the Cosmic Reionization On Computers (CROC) project with the exiting UV and IR data. Since CROC simulations do not follow cosmic dust directly, we adopt two variants of the dust-follows-metals ansatz to populate model galaxies with dust. Using the dust radiative transfer code Hyperion, we compute synthetic stellar spectra, UV continuum slopes, and IR fluxes for simulated galaxies. We find that the simulation results generally match observational measurements, but, perhaps, not in full detail. The differences seem to indicate that our adopted dust-follows-metals ansatzes are not fully sufficient. While the discrepancies with the exiting data are marginal, the future JWST data will be of much higher precision, rendering highly significant any tentative difference between theory and observations. It is, therefore, likely, that in order to fully utilize the precision of JWST observations, fully dynamical modeling of dust formation, evolution, and destruction may be required.
|
نقارن خصائص تجمعات النجوم في المجرات النموذجية من مشروع إعادة تأين الكون باستخدام الحواسيب (CROC) مع البيانات الحالية في الأشعة فوق البنفسجية والأشعة تحت الحمراء. وبما أن محاكاة CROC لا تتبع الغبار الكوني بشكل مباشر، نعتمد نهجهما بديهيتين من نوع "اتباع الغبار للمعادن" لتوزيع الغبار في المجرات النموذجية. وباستخدام برنامج نقل الإشعاع الغباري Hyperion، نحسب الطيف النجمي الاصطناعي، وانحدارات المستمر في الأشعة فوق البنفسجية، وتدفقات الأشعة تحت الحمراء للمجرات المحاكاة. نجد أن نتائج المحاكاة تتطابق عمومًا مع القياسات الرصدية، ولكن ربما ليس بالتفصيل الكامل. تشير الاختلافات إلى أن الفرضيتين اللتين اعتمدناهما بشأن اتباع الغبار للمعادن ليستا كافيتين تمامًا. وعلى الرغم من أن التباينات مع البيانات الحالية هامشية، فإن بيانات تلسكوب جيمس ويب الفضائي (JWST) المستقبلية ستكون بدقة أعلى بكثير، ما يجعل أي فرق طفيف بين النظرية والمشاهدات ذا دلالة إحصائية كبيرة. لذلك، من المرجح أنه من أجل الاستفادة الكاملة من دقة ملاحظات JWST، قد يتطلب الأمر نمذجة ديناميكية كاملة لتكوين الغبار وتطوره وتدميره.
|
ar
|
We investigate instantons near a tachyonic top in an anti de Sitter (AdS) background. If the mass scale around the hill-top is above the Breitenlohner-Freedman (BF) bound, then the top is classically stable. When the BF bound is satisfied, it is already known that there can exist instantons with a non-zero probability, though fine-tunings of the potential are required. On the other hand, we may consider a possibility to obtain instantons with a non-zero probability for more natural shape of potentials. We found that the no-boundary regulator is useful to assign a non-zero probability for general instantons near the tachyonic top with a consistent framework. To use the no-boundary regulator, we need to introduce the complexification of fields. One interesting feature is that, for these AdS instantons, the classicality may not be satisfied after the Wick rotation and hence after the nucleation. This magnifies a novel difference between dS and AdS; a semi-classical boundary observer in AdS may notice the dispersion of quantum fields as a kind of uncertainty, while every semi-classical observers in dS are classicalized individually and hence there is no semi-classical observer who can see the quantum dispersion of the scalar field.
|
ကျွန်ုပ်တို့သည် anti de Sitter (AdS) နောက်ခံတွင် တက်ချျုနစ် (tachyonic) ထိပ်အနီးရှိ အီးစတွန်များကို စူးစမ်းလေ့လာကြသည်။ တောင်ကြားထိပ်ပတ်လည်ရှိ မာလ်စကေးသည် Breitenlohner-Freedman (BF) နယ်နှောင်းထက်ကျော်လွန်နေပါက ထိပ်သည် ရူပဗေဒအရ တည်ငြိမ်မှုရှိပါသည်။ BF နယ်နှောင်း ကျော်လွန်နေပါက အလားအလာကို သော့ချက်ကိုက်ညှိပေးရန် လိုအပ်သော်လည်း မသုညဖြစ်သော ဖြစ်နိုင်ခြေရှိသည့် အီးစတွန်များ ရှိနိုင်သည်ဟု ယခင်က သိရှိထားပြီးဖြစ်သည်။ အခြားတစ်ဖက်တွင် ပို၍ သဘာဝကျသော အလားအလာပုံသဏ္ဍာန်များအတွက် မသုညဖြစ်သော ဖြစ်နိုင်ခြေရှိသည့် အီးစတွန်များရရှိရန် ဖြစ်နိုင်ခြေကို စဉ်းစားနိုင်ပါသည်။ တက်ချျုနစ်ထိပ်နီးပါးရှိ အီးစတွန်များအတွက် မသုညဖြစ်သော ဖြစ်နိုင်ခြေကို သတ်မှတ်ပေးရန် နိုဗွိုင်ဒရီဂျီလေးတာ (no-boundary regulator) သည် ကိုက်ညီသော ကွက်ချပ်တစ်ခုဖြင့် အသုံးဝင်ကြောင်း တွေ့ရှိခဲ့သည်။ နိုဗွိုင်ဒရီဂျီလေးတာကို အသုံးပြုရန်အတွက် အားများ၏ ကွန်ပလက်စ်ပြုလုပ်မှုကို မိတ်ဆက်ပေးရန် လိုအပ်ပါသည်။ ထူးခြားသည့် အင်္ဂါရပ်တစ်ခုမှာ ဤ AdS အီးစတွန်များအတွက် Wick လှည့်ခြင်းပြီးနောက် နှင့် ထို့နောက် နျူကလီယိုင်းဇင်းပြီးနောက်တွင် ရူပဗေဒအရ ဖြစ်ခြင်း (classicality) ကို မဖြည့်ဆည်းနိုင်ပါ။ ဤအချက်သည် dS နှင့် AdS ကြားရှိ ကွဲပြားမှုသစ်တစ်ခုကို ပို၍ ထင်ရှားစေပါသည်။ AdS တွင် ရူပဗေဒအရ နယ်စပ်အတောင့်အတာရှိ စူးစမ်းသူသည် ကွမ်တမ် အားများ၏ ပျံ့နှံ့မှုကို မသေချာမရေရာမှုအမျိုးအစားတစ်ခုအဖြစ် သတိပြုမိနိုင်သော်လည်း dS ရှိ ရူပဗေဒအရ စူးစမ်းသူအားလုံးသည် တစ်ဦးချင်းစီ ရူပဗေဒအရ ဖြစ်လာကြပြီးဖြစ်သောကြောင့် စကေလားဖိုင်များ၏ ကွမ်တမ်ပျံ့နှံ့မှုကို မြင်တွေ့နိုင်သည့် ရူပဗေဒအရ စူးစမ်းသူမရှိပါ။
|
my
|
Shape Dynamics is a theory of gravity that replaces refoliation invariance for spatial Weyl invariance. Those solutions of the Einstein equations that have global, constant mean curvature slicings, are mirrored by solutions in Shape Dynamics. However, there are solutions of Shape Dynamics that have no counterpart in General relativity, just as there are solutions of GR that are not completely foliable by global constant mean curvature slicings (such as the Schwarzschild spacetime). It is therefore interesting to analyze directly the equations of motion of Shape Dynamics in order to find its own solutions, irrespective of properties of known solutions of GR. Here I perform a first study in this direction by utilizing the equations of motion of Shape Dynamics in a spherically symmetric, asymptotically flat ansatz to derive an analogue of the Birkhoff theorem. There are two significant differences with respect to the usual Birkhoff theorem in GR. The first regards the construction of the solution: the spatial Weyl gauge freedom of shape dynamics is used to simplify the problem, and boundary conditions are required. In fact the derivation is simpler than the usual Birkhof theorem as no Christoffel symbols are needed. The second, and most important difference is that the solution obtained is uniquely the isotropic wormhole solution, in which no singularity is present, as opposed to maximally extended Schwarzschild. This provides an explicit example of the breaking of the duality between General relativity and Shape Dynamics, and exhibits some of its consequences.
|
ရုပ်သွင်အက်စ်ဒီနမစ် (Shape Dynamics) သည် အာကာသဆိုင်ရာ ဝေးလ် မှီငြမ်းမှု (spatial Weyl invariance) အတွက် ပြန်လည်ဖွဲ့စည်းမှု မှီငြမ်းမှုကို အစားထိုးသည့် ဆွဲဆောင်အားသီအိုရီတစ်ခုဖြစ်သည်။ ကမ္ဘာလုံးဆိုင်ရာ အလယ်ဗဟိုအရှိန်တန်ဖိုး အပိုင်းအစများရှိသည့် အိုင်းစတိုင်း ညီမျှခြင်းများ၏ အဖြေများသည် ရုပ်သွင်အက်စ်ဒီနမစ်ရှိ အဖြေများဖြင့် ထင်ဟပ်ပေါ်လွင်နေပါသည်။ သို့သော် ယေဘုယျ ဆွဲဆောင်အားဖြင့် (General Relativity) တွင် အဖြေမရှိသည့် ရုပ်သွင်အက်စ်ဒီနမစ်၏ အဖြေများရှိပြီး ကမ္ဘာလုံးဆိုင်ရာ အလယ်ဗဟိုအရှိန်တန်ဖိုး အပိုင်းအစများဖြင့် အပြည့်အဝ မဖွဲ့စည်းနိုင်သည့် အဖြေများ (ဥပမာ- ရှွာ့စ်ချ်လ်ဗာ့စ်ပိုင်းအကွာအဝေး) ကဲ့သို့ပင် ဖြစ်ပါသည်။ ထို့ကြောင့် ရုပ်သွင်အက်စ်ဒီနမစ်၏ လှုပ်ရှားမှု ညီမျှခြင်းများကို တိုက်ရိုက် ဆန်းစစ်လေ့လာ၍ ရုပ်သွင်အက်စ်ဒီနမစ်၏ ကိုယ်ပိုင်အဖြေများကို GR ၏ သိထားသည့် အဖြေများ၏ ဂုဏ်သတ္တိများကို အခြေခံခြင်းမရှိဘဲ ရှာဖွေရန် စိတ်ဝင်စားဖွယ်ရာ ဖြစ်ပါသည်။ ဤတွင် စဖီးရစ်ကယ် အချင်းဝင် (spherically symmetric)၊ အဆုံးမရှိ ပြားချပ် (asymptotically flat) အကြံအစည်ကို အသုံးပြု၍ ဘာခ်ဟော့ဖ်သီအိုရမ် (Birkhoff theorem) ၏ အစားထိုးမှုကို ရယူရန် ရုပ်သွင်အက်စ်ဒီနမစ်၏ လှုပ်ရှားမှု ညီမျှခြင်းများကို အသုံးပြု၍ ဤဦးတည်ရာသို့ ပထမဆုံးလေ့လာမှုတစ်ခုကို ပြုလုပ်ပါသည်။ GR ရှိ ပုံမှန် ဘာခ်ဟော့ဖ်သီအိုရမ်နှင့် နှိုင်းယှဉ်ပါက ကွဲပြားမှု နှစ်ခု ရှိပါသည်။ ပထမတစ်ခုမှာ အဖြေကို တည်ဆောက်ပုံနှင့် ပတ်သက်ပြီးဖြစ်ပြီး ရုပ်သွင်အက်စ်ဒီနမစ်၏ အာကာသဆိုင်ရာ ဝေးလ် ဂေ့ဂ် လွတ်လပ်ခွင့်ကို ပြဿနာကို ရိုးရှင်းစေရန် အသုံးပြုပြီး နယ်နိမိတ် အခြေအနေများ လိုအပ်ပါသည်။ အမှန်တကယ် ကွဲလွဲချက်မှာ ခရစ်စတော်ဖယ် သင်္ကေတများ မလိုအပ်သောကြောင့် ပုံမှန် ဘာခ်ဟော့ဖ်သီအိုရမ်ကို ရယူခြင်းထက် ပို၍ရိုးရှင်းပါသည်။ ဒုတိယနှင့် အရေးကြီးဆုံးကွဲပြားချက်မှာ ရရှိသည့် အဖြေသည် အိုင်ဆိုတရော့ပ် ဝါ့မ်ဟိုလ် (isotropic wormhole) အဖြေသာ ဖြစ်ပြီး အများဆုံး ချဲ့ထွင်ထားသည့် ရှွာ့စ်ချ်လ်ဗာ့စ်နှင့် မတူဘဲ အကွဲအပိုင်း (singularity) မပါဝင်ပါ။ ဤအရာသည် ယေဘုယျ ဆွဲဆောင်အားနှင့် ရုပ်သွင်အက်စ်ဒီနမစ် အကြား ဒွိဟဖြစ်မှုကို ချိုးဖျက်မှု၏ ရှင်းလင်းသော ဥပမာတစ်ခုဖြစ်ပြီး ၎င်း၏ နောက်ဆက်တွဲများကို ဖော်ပြပေးပါသည်။
|
my
|
Large amounts of labeled training data are one of the main contributors to the great success that deep models have achieved in the past. Label acquisition for tasks other than benchmarks can pose a challenge due to requirements of both funding and expertise. By selecting unlabeled examples that are promising in terms of model improvement and only asking for respective labels, active learning can increase the efficiency of the labeling process in terms of time and cost. In this work, we describe combinations of an incremental learning scheme and methods of active learning. These allow for continuous exploration of newly observed unlabeled data. We describe selection criteria based on model uncertainty as well as expected model output change (EMOC). An object detection task is evaluated in a continuous exploration context on the PASCAL VOC dataset. We also validate a weakly supervised system based on active and incremental learning in a real-world biodiversity application where images from camera traps are analyzed. Labeling only 32 images by accepting or rejecting proposals generated by our method yields an increase in accuracy from 25.4% to 42.6%.
|
تُعد كميات كبيرة من بيانات التدريب المُصنفة أحد العوامل الرئيسية التي ساهمت في النجاح الكبير الذي حققته النماذج العميقة في الماضي. قد يشكل الحصول على التصنيفات للمهام الأخرى التي لا تتعلق بمعايير المقارنة تحدياً بسبب اشتراطات التمويل والخبرة. من خلال اختيار الأمثلة غير المصنفة التي تُعد واعدة من حيث تحسين النموذج، وطلب التصنيفات الخاصة بها فقط، يمكن لتقنية التعلم النشط أن تزيد من كفاءة عملية التصنيف من حيث الوقت والتكلفة. في هذا العمل، نصف توليفات تجمع بين نمط تعلم تدريجي وأساليب التعلم النشط، مما يتيح الاستكشاف المستمر للبيانات غير المصنفة التي تُلاحظ حديثاً. نصف معايير اختيار تعتمد على عدم اليقين في النموذج وكذلك على التغير المتوقع في مخرجات النموذج (EMOC). يتم تقييم مهمة اكتشاف الكائنات في سياق استكشاف مستمر باستخدام مجموعة بيانات PASCAL VOC. كما نتحقق من صحة نظام خاضع لإشراف ضعيف يعتمد على التعلم النشط والتدريجي في تطبيق حقيقي متعلق بالتنوع البيولوجي، حيث تُحلل الصور المستمدة من كاميرات المراقبة. ويكفي تصنيف 32 صورة فقط من خلال قبول أو رفض الاقتراحات التي يولدها منهجنا لتحقيق زيادة في الدقة من 25.4% إلى 42.6%.
|
ar
|
Let A be a C*-algebra and A** its enveloping von Neumann algebra. C. Akemann suggested a kind of non-commutative topology in which certain projections in A** play the role of open sets. The adjectives "open", "closed", "compact", and "relatively compact" all can be applied to projections in A**. Two operator inequalities were used by Akemann in connection with compactness. Both of these inequalities are equivalent to compactness for a closed projection in A**, but only one is equivalent to relative compactness for a general projection. A third operator inequality, also related to compactness, was used by the author. It turns out that the study of all three inequalities can be unified by considering a numerical invariant which is equivalent to the distance of a projection from the set of relatively compact projections. Since the subject concerns the relation between a projection and its closure, Tomita's concept of regularity of projections seems relevant, and some results and examples on regularity are also given. A few related results on semicontinuity are also included.
|
Seja A uma C*-álgebra e A** sua álgebra de von Neumann envolvente. C. Akemann sugeriu um tipo de topologia não comutativa na qual certas projeções em A** desempenham o papel de conjuntos abertos. Os adjetivos "aberto", "fechado", "compacto" e "relativamente compacto" podem todos ser aplicados a projeções em A**. Duas desigualdades operacionais foram utilizadas por Akemann em conexão com compacidade. Ambas essas desigualdades são equivalentes à compacidade para uma projeção fechada em A**, mas apenas uma delas é equivalente à compacidade relativa para uma projeção geral. Uma terceira desigualdade operacional, também relacionada à compacidade, foi usada pelo autor. Verifica-se que o estudo das três desigualdades pode ser unificado ao considerar-se uma invariante numérica que é equivalente à distância de uma projeção ao conjunto das projeções relativamente compactas. Uma vez que o assunto trata da relação entre uma projeção e seu fecho, o conceito de Tomita de regularidade de projeções parece relevante, e alguns resultados e exemplos sobre regularidade também são apresentados. Alguns resultados relacionados à semicontinuidade também são incluídos.
|
pt
|
The Supernova Cosmology Project has discovered over twenty-eight supernovae (SNe) at 0.35 <z < 0.65 in an ongoing program that uses Type Ia SNe as high-redshift distance indicators. Here we present measurements of the ratio between the locally observed and global Hubble constants, H_0^L/H_0^G, based on the first 7 SNe of this high-redshift data set compared with 18 SNe at z <= 0.1 from the Calan/Tololo survey. If Omega_M <= 1, then light-curve-width corrected SN magnitudes yield H_0^L/H_0^G < 1.10 (95% confidence level) in both a Lambda=0 and a flat universe. The analysis using the SNe Ia as standard candles without a light-curve-width correction yields similar results. These results rule out the hypothesis that the discrepant ages of the Universe derived from globular clusters and recent measurements of the Hubble constant are attributable to a locally underdense bubble. Using the Cepheid-distance-calibrated absolute magnitudes for SNe Ia of Sandage (1996}, we can also measure the global Hubble constant, H_0^G. If Omega_M >= 0.2, we find that H_0^G < 70 km/s/Mpc in a Lambda=0 universe and H_0^G < 78 km/s/Mpc in a flat universe, correcting the distant and local SN apparent magnitudes for light curve width. Lower results for H_0^G are obtained if the magnitudes are not width corrected.
|
초신성 공동 연구 프로젝트(Supernova Cosmology Project)는 고적색이동 거리 지표로서 타입 Ia 초신성(SNe)을 사용하는 지속적인 연구 프로그램을 통해 0.35 < z < 0.65 범위에서 28개 이상의 초신성을 발견하였다. 본 논문에서는 칼란/톨로로 조사(Calan/Tololo survey)에서 얻은 z ≤ 0.1인 18개의 초신성과 비교하여, 이 고적색이동 데이터 세트의 처음 7개 초신성을 기반으로 지역에서 관측된 후버 상수와 전역 후버 상수의 비율(H_0^L/H_0^G)을 측정한 결과를 제시한다. 만약 Ω_M ≤ 1이라면, 광곡선 폭 보정을 적용한 초신성의 등급은 Λ=0인 우주와 평탄한 우주 모두에서 H_0^L/H_0^G < 1.10(95% 신뢰수준)을 산출한다. 광곡선 폭 보정을 적용하지 않고 타입 Ia 초신성을 표준촛불로 사용하는 분석도 유사한 결과를 얻는다. 이러한 결과들은 구상성단으로부터 도출된 우주의 나이와 최근의 후버 상수 측정값 사이의 불일치가 지역적으로 밀도가 낮은 거품(bubble)에 기인했다는 가설을 배제한다. 샌데이지(Sandage, 1996)의 세페이드 거리 기준으로 보정된 타입 Ia 초신성의 절대 등급을 사용하면 전역 후버 상수 H_0^G도 측정할 수 있다. 만약 Ω_M ≥ 0.2이라면, 광곡선 폭에 대한 보정을 거친 먼 거리 및 지역 초신성의 겉보기 등급을 기준으로 Λ=0인 우주에서는 H_0^G < 70 km/s/Mpc, 평탄한 우주에서는 H_0^G < 78 km/s/Mpc를 얻는다. 등급에 대해 폭 보정을 적용하지 않을 경우 H_0^G의 값은 더 낮아진다.
|
ko
|
The cosmic microwave background (CMB) temperature anisotropies exhibit a large-scale dipolar power asymmetry. To determine whether this is due to a real, physical modulation or is simply a large statistical fluctuation requires the measurement of new modes. Here we forecast how well CMB polarization data from \Planck\ and future experiments will be able to confirm or constrain physical models for modulation. Fitting several such models to the \Planck\ temperature data allows us to provide predictions for polarization asymmetry. While for some models and parameters \Planck\ polarization will decrease error bars on the modulation amplitude by only a small percentage, we show, importantly, that cosmic-variance-limited (and in some cases even \Planck) polarization data can decrease the errors by considerably better than the expectation of $\sqrt 2$ based on simple $\ell$-space arguments. We project that if the primordial fluctuations are truly modulated (with parameters as indicated by \Planck\ temperature data) then \Planck\ will be able to make a 2$\sigma$ detection of the modulation model with 20--75\% probability, increasing to 45--99\% when cosmic-variance-limited polarization is considered. We stress that these results are quite model dependent. Cosmic variance in temperature is important: combining statistically isotropic polarization with temperature data will spuriously increase the significance of the temperature signal with 30\% probability for \Planck.
|
تُظهر تباينات درجة حرارة الخلفية الميكروويفية الكونية (CMB) عدم تماثل قطبي على نطاقات واسعة. ولتحديد ما إذا كان هذا الناتج عن تضمين فيزيائي حقيقي أو مجرد تقلبات إحصائية كبيرة، يتطلب الأمر قياس أوضاع جديدة. هنا نُقدِّر مدى دقة بيانات استقطاب CMB من مهمة بلانك (Planck) والتجارب المستقبلية في التأكد من نماذج التضمين أو تقييدها. وبمطابقة عدة نماذج من هذا النوع مع بيانات درجة حرارة بلانك، نستطيع تقديم تنبؤات بشأن عدم التماثل في الاستقطاب. وبينما ستؤدي بيانات الاستقطاب من بلانك في بعض النماذج والمعطيات إلى تقليل أشرطة الخطأ في سعة التضمين بنسبة ضئيلة فقط، نُبيّن، بشكل مهم، أن بيانات الاستقطاب المحدودة بالتباين الكوني (وفي بعض الحالات حتى بيانات بلانك) يمكن أن تقلل الأخطاء بنسبة أفضل بكثير من التوقع البالغ $\sqrt 2$ المستند إلى حجج بسيطة في فضاء $\ell$. نُقدِّر أنه إذا كانت التقلبات الابتدائية مُضمنة فعلاً (بمعلمات تشير إليها بيانات درجة حرارة بلانك)، فإن بلانك سيكون قادراً على تحقيق اكتشاف بمستوى 2$\sigma$ لنموذج التضمين باحتمال يتراوح بين 20–75%، ويزداد هذا الاحتمال إلى 45–99% عند أخذ بيانات الاستقطاب المحدودة بالتباين الكوني في الاعتبار. نؤكد أن هذه النتائج تعتمد بشكل كبير على النموذج. إن التباين الكوني في درجة الحرارة مهم: إن دمج الاستقطاب المتماثل إحصائياً مع بيانات درجة الحرارة سيؤدي، باحتمال 30% لبلانك، إلى زيادة وهمية في دلالة إشارة درجة الحرارة.
|
ar
|
Source code (Context) and its parsed abstract syntax tree (AST; Structure) are two complementary representations of the same computer program. Traditionally, designers of machine learning models have relied predominantly either on Structure or Context. We propose a new model, which jointly learns on Context and Structure of source code. In contrast to previous approaches, our model uses only language-agnostic features, i.e., source code and features that can be computed directly from the AST. Besides obtaining state-of-the-art on monolingual code summarization on all five programming languages considered in this work, we propose the first multilingual code summarization model. We show that jointly training on non-parallel data from multiple programming languages improves results on all individual languages, where the strongest gains are on low-resource languages. Remarkably, multilingual training only from Context does not lead to the same improvements, highlighting the benefits of combining Structure and Context for representation learning on code.
|
সোর্স কোড (কনটেক্সট) এবং এর পার্সড এবস্ট্রাক্ট সিনট্যাক্স ট্রি (AST; স্ট্রাকচার) একই কম্পিউটার প্রোগ্রামের দুটি পরস্পর পূরক উপস্থাপনা। ঐতিহ্যগতভাবে, মেশিন লার্নিং মডেলের ডিজাইনাররা প্রধানত হয় স্ট্রাকচার অথবা কনটেক্সটের উপর নির্ভর করেছেন। আমরা একটি নতুন মডেল প্রস্তাব করছি, যা সোর্স কোডের কনটেক্সট এবং স্ট্রাকচার উভয়ের উপর যৌথভাবে শেখে। আগের পদ্ধতির বিপরীতে, আমাদের মডেলটি শুধুমাত্র ভাষানিরপেক্ষ বৈশিষ্ট্য ব্যবহার করে, অর্থাৎ সোর্স কোড এবং এমন বৈশিষ্ট্য যা সরাসরি AST থেকে গণনা করা যায়। এই কাজে বিবেচিত সমস্ত পাঁচটি প্রোগ্রামিং ভাষায় একক ভাষার কোড সামারাইজেশনে শীর্ষস্থানীয় ফলাফল অর্জনের পাশাপাশি, আমরা প্রথম বহুভাষিক কোড সামারাইজেশন মডেলটি প্রস্তাব করি। আমরা দেখাই যে একাধিক প্রোগ্রামিং ভাষা থেকে অ-সমান্তরাল ডেটাতে যৌথভাবে প্রশিক্ষণ দেওয়া সমস্ত একক ভাষার জন্য ফলাফল উন্নত করে, যেখানে সবচেয়ে বড় উন্নতি হয় কম সম্পদযুক্ত ভাষাগুলিতে। উল্লেখযোগ্যভাবে, শুধুমাত্র কনটেক্সট থেকে বহুভাষিক প্রশিক্ষণ একই উন্নতি দেয় না, যা কোডের জন্য রিপ্রেজেন্টেশন লার্নিংয়ে স্ট্রাকচার এবং কনটেক্সট একত্রিত করার সুবিধাগুলি তুলে ধরে।
|
bn
|
Let A be a C*-algebra and A** its enveloping von Neumann algebra. C. Akemann suggested a kind of non-commutative topology in which certain projections in A** play the role of open sets. The adjectives "open", "closed", "compact", and "relatively compact" all can be applied to projections in A**. Two operator inequalities were used by Akemann in connection with compactness. Both of these inequalities are equivalent to compactness for a closed projection in A**, but only one is equivalent to relative compactness for a general projection. A third operator inequality, also related to compactness, was used by the author. It turns out that the study of all three inequalities can be unified by considering a numerical invariant which is equivalent to the distance of a projection from the set of relatively compact projections. Since the subject concerns the relation between a projection and its closure, Tomita's concept of regularity of projections seems relevant, and some results and examples on regularity are also given. A few related results on semicontinuity are also included.
|
A を C*環とし、A** をその包絡フォン・ノイマン環とする。C. アケマンは、A** 内のある種の射影が開集合の役割を果たすような、ある種の非可換位相を提唱した。形容詞「開」「閉」「コンパクト」「相対コンパクト」はすべて、A** 内の射影に適用することができる。アケマンはコンパクト性に関連して、二つの作用素不等式を用いた。これらの不等式の両方は、A** 内の閉射影に対してコンパクト性と同値であるが、一般の射影に対して相対コンパクト性と同値なのはそのうちの一方だけである。著者はコンパクト性に関連して第三の作用素不等式を用いた。結局のところ、射影から相対コンパクト射影の集合までの距離と同値な数値不変量を考えることによって、これら三つの不等式の研究を統一的に扱えることがわかる。この主題は射影とその閉包との関係を扱うものであるため、冨田の射影の正則性の概念が関連しており、正則性に関するいくつかの結果と例も与えられている。半連続性に関する関連する結果もいくつか含んでいる。
|
ja
|
The advantages of adaptivity and feedback are of immense interest in signal processing and communication with many positive and negative results. Although it is established that adaptivity does not offer substantial reductions in minimax mean square error for a fixed number of measurements, existing results have shown several advantages of adaptivity in complexity of reconstruction, accuracy of support detection, and gain in signal-to-noise ratio, under constraints on sensing energy. Sensing energy has often been measured in terms of the Frobenius Norm of the sensing matrix. This paper uses a different metric that we call the $l_0$ cost of a sensing matrix-- to quantify the complexity of sensing. Thus sparse sensing matrices have a lower cost. We derive information-theoretic lower bounds on the $l_0$ cost that hold for any non-adaptive sensing strategy. We establish that any non-adaptive sensing strategy must incur an $l_0$ cost of $\Theta\left( N \log_2(N)\right) $ to reconstruct an $N$-dimensional, one--sparse signal when the number of measurements are limited to $\Theta\left(\log_2 (N)\right)$. In comparison, bisection-type adaptive strategies only require an $l_0$ cost of at most $\mathcal{O}(N)$ for an equal number of measurements. The problem has an interesting interpretation as a sphere packing problem in a multidimensional space, such that all the sphere centres have minimum non-zero co-ordinates. We also discuss the variation in $l_0$ cost as the number of measurements increase from $\Theta\left(\log_2 (N)\right)$ to $\Theta\left(N\right)$.
|
Kelebihan penyesuaian dan suapan balik amat menarik dalam pemprosesan isyarat dan perhubungan dengan pelbagai keputusan positif dan negatif. Walaupun telah ditunjukkan bahawa penyesuaian tidak memberikan pengurangan besar dalam ralat kuasa dua min maksimum untuk bilangan ukuran yang tetap, keputusan sedia ada telah menunjukkan beberapa kelebihan penyesuaian dari segi kompleksiti pembinaan semula, ketepatan pengesanan sokongan, dan peningkatan nisbah isyarat terhadap bunyi bocor, di bawah kekangan tenaga penderiaan. Tenaga penderiaan kerap diukur dari segi Norma Frobenius bagi matriks penderiaan. Kertas kerja ini menggunakan metrik yang berbeza yang kami sebut kos $l_0$ bagi matriks penderiaan—untuk mengukur kompleksiti penderiaan. Maka, matriks penderiaan jarang mempunyai kos yang lebih rendah. Kami menerbitkan batas bawah maklumat-teoretik bagi kos $l_0$ yang sah untuk sebarang strategi penderiaan bukan penyesuaian. Kami menubuhkan bahawa mana-mana strategi penderiaan bukan penyesuaian mesti menanggung kos $l_0$ sebanyak $\Theta\left( N \log_2(N)\right) $ untuk membina semula isyarat satu-jarang berdimensi $N$ apabila bilangan ukuran terhad kepada $\Theta\left(\log_2 (N)\right)$. Sebagai perbandingan, strategi penyesuaian jenis pembahagian dua hanya memerlukan kos $l_0$ maksimum $\mathcal{O}(N)$ bagi bilangan ukuran yang sama. Masalah ini mempunyai tafsiran menarik sebagai masalah pengepakan sfera dalam ruang berbilang dimensi, sedemikian rupa sehingga semua pusat sfera mempunyai koordinat bukan sifar minimum. Kami juga membincangkan variasi dalam kos $l_0$ apabila bilangan ukuran meningkat dari $\Theta\left(\log_2 (N)\right)$ kepada $\Theta\left(N\right)$.
|
ms
|
We compare the properties of stellar populations of model galaxies from the Cosmic Reionization On Computers (CROC) project with the exiting UV and IR data. Since CROC simulations do not follow cosmic dust directly, we adopt two variants of the dust-follows-metals ansatz to populate model galaxies with dust. Using the dust radiative transfer code Hyperion, we compute synthetic stellar spectra, UV continuum slopes, and IR fluxes for simulated galaxies. We find that the simulation results generally match observational measurements, but, perhaps, not in full detail. The differences seem to indicate that our adopted dust-follows-metals ansatzes are not fully sufficient. While the discrepancies with the exiting data are marginal, the future JWST data will be of much higher precision, rendering highly significant any tentative difference between theory and observations. It is, therefore, likely, that in order to fully utilize the precision of JWST observations, fully dynamical modeling of dust formation, evolution, and destruction may be required.
|
Ihahambing natin ang mga katangian ng mga populasyon ng bituin sa mga modelong galaksi mula sa proyektong Cosmic Reionization On Computers (CROC) sa umiiral na datos sa UV at IR. Dahil ang mga CROC na simulasyon ay hindi direktang sinusundan ang alikabok na kosmiko, gumagamit tayo ng dalawang bersyon ng dust-follows-metals ansatz upang mapunan ng alikabok ang mga modelong galaksi. Gamit ang code sa radiative transfer ng alikabok na Hyperion, kinokompyut natin ang mga sintetikong espektrong bituin, mga slope ng UV continuum, at mga daloy ng IR para sa mga naisimulang galaksi. Natagpuan natin na ang mga resulta ng simulasyon ay karaniwang tugma sa mga pagsukat na obserbasyonal, ngunit marahil ay hindi sa buong detalye. Ang mga pagkakaiba ay tila nagpapahiwatig na ang aming mga adoptadong dust-follows-metals ansatz ay hindi lubos na sapat. Bagaman ang mga pagkakaiba sa umiiral na datos ay bahagyang marginal lamang, ang hinaharap na datos ng JWST ay magiging mas mataas ang presisyon, kaya't magiging lubhang makabuluhan ang anumang pansamantalang pagkakaiba sa pagitan ng teorya at obserbasyon. Samakatuwid, malamang na upang lubos na mapakinabangan ang presisyon ng mga obserbasyon ng JWST, kailangan ang ganap na dynamikong pagmomodelo ng pormasyon, ebolusyon, at pagkawasak ng alikabok.
|
tl
|
Transformer, as a strong and flexible architecture for modelling long-range relations, has been widely explored in vision tasks. However, when used in video inpainting that requires fine-grained representation, existed method still suffers from yielding blurry edges in detail due to the hard patch splitting. Here we aim to tackle this problem by proposing FuseFormer, a Transformer model designed for video inpainting via fine-grained feature fusion based on novel Soft Split and Soft Composition operations. The soft split divides feature map into many patches with given overlapping interval. On the contrary, the soft composition operates by stitching different patches into a whole feature map where pixels in overlapping regions are summed up. These two modules are first used in tokenization before Transformer layers and de-tokenization after Transformer layers, for effective mapping between tokens and features. Therefore, sub-patch level information interaction is enabled for more effective feature propagation between neighboring patches, resulting in synthesizing vivid content for hole regions in videos. Moreover, in FuseFormer, we elaborately insert the soft composition and soft split into the feed-forward network, enabling the 1D linear layers to have the capability of modelling 2D structure. And, the sub-patch level feature fusion ability is further enhanced. In both quantitative and qualitative evaluations, our proposed FuseFormer surpasses state-of-the-art methods. We also conduct detailed analysis to examine its superiority.
|
Ang Transformer, bilang isang matibay at nababaluktot na arkitektura para sa pagmamodelo ng mga ugnayang may malawak na sakop, ay malawakang naipagpatuloy sa mga gawain sa larangan ng paningin. Gayunpaman, kapag ginamit sa pagkukumpuni ng video na nangangailangan ng detalyadong representasyon, ang mga umiiral na pamamaraan ay nakakaranas pa rin ng pagkakaroon ng mga blurry na gilid dahil sa mahigpit na paghahati ng mga patch. Dito, layunin naming harapin ang problemang ito sa pamamagitan ng pagmumungkahi ng FuseFormer, isang modelo ng Transformer na dinisenyo para sa pagkukumpuni ng video sa pamamagitan ng pino at detalyadong pagsasama ng mga katangian na batay sa mga bagong operasyon ng Soft Split at Soft Composition. Ang soft split ay naghihiwalay sa feature map sa maraming mga patch na may takdang overlapping interval. Sa kabilang banda, ang soft composition ay gumagana sa pamamagitan ng pagdudugtong ng iba't ibang mga patch sa isang buong feature map kung saan ang mga pixel sa mga overlapping na rehiyon ay pinagsama. Ang dalawang module na ito ay ginagamit muna sa tokenization bago ang mga layer ng Transformer at sa de-tokenization pagkatapos ng mga layer ng Transformer, para sa epektibong pagmamapa sa pagitan ng mga token at mga katangian. Dahil dito, ang interaksyon ng impormasyon sa sub-patch level ay napapaganap para sa mas epektibong pagpapalaganap ng mga katangian sa pagitan ng magkakalapit na mga patch, na nagreresulta sa pagbuo ng buhay na nilalaman para sa mga butas o puwang sa mga video. Bukod dito, sa FuseFormer, masinsin naming isinasama ang soft composition at soft split sa feed-forward network, na nagbibigay sa mga 1D linear layer ng kakayahang magmodelo ng 2D na istruktura. At, ang kakayahan sa pagsasama ng mga katangian sa sub-patch level ay lalo pang napapahusay. Sa parehong pagsusuri na kwalitatibo at kwalitatibo, ang aming iminungkahing FuseFormer ay lumalampas sa mga kasalukuyang pinakamahusay na pamamaraan. Isinagawa rin namin ang detalyadong pagsusuri upang suriin ang kahusayan nito.
|
tl
|
We made a supplemental study of the superoutbursts and superhumps in SU UMa stars by using the recently released Kepler public data of V1504 Cyg and V344 Lyr. One of the superoutbursts in V1504 Cyg was preceded by a precursor normal outburst which was well separated from the main superoutburst. The superhump first appeared during the descending branch of the precursor normal outburst and it continued into quiescence (the deep dip between the precursor and the main superoutburst), and it began to grow in amplitude with the growth of the main superoutburst after quiescence ended. A similar phenomenon was also observed in V344 Lyr. This observation demonstrates very clearly that the superoutburst was triggered by the superhump (i.e., by the tidal instability), supporting the thermal-tidal instability model. Smak (2013, Acta Astron., 63, 109, arXiv:1301.0187) criticized our previous paper (Osaki and Kato, 2013, PASJ, 65, 50, arXiv:1212.1516) and challenged our main conclusion that various observational lines of evidence of V1504 Cyg support the thermal-tidal instability model for the superoutbursts of SU UMa stars. We present our detailed accounts to all of his criticisms by offering clear explanations. We conclude that the thermal-tidal instability model is after all only the viable model for the superoutbursts and superhumps in SU UMa stars.
|
Kami melakukan studi tambahan mengenai superletupan dan superjungkiran pada bintang SU UMa dengan menggunakan data publik Kepler yang baru dirilis untuk V1504 Cyg dan V344 Lyr. Salah satu superletupan pada V1504 Cyg didahului oleh letupan normal pendahulu yang terpisah dengan jelas dari superletupan utama. Superjungkiran pertama kali muncul selama cabang penurunan letupan normal pendahulu tersebut dan berlanjut hingga masa kelesuan (cekungan dalam antara letupan pendahulu dan superletupan utama), kemudian mulai tumbuh amplitudonya seiring pertumbuhan superletupan utama setelah masa kelesuan berakhir. Fenomena serupa juga diamati pada V344 Lyr. Pengamatan ini menunjukkan dengan sangat jelas bahwa superletupan dipicu oleh superjungkiran (yakni oleh ketidakstabilan pasang), sehingga mendukung model ketidakstabilan termal-pasang. Smak (2013, Acta Astron., 63, 109, arXiv:1301.0187) mengkritik makalah kami sebelumnya (Osaki dan Kato, 2013, PASJ, 65, 50, arXiv:1212.1516) serta menyanggah kesimpulan utama kami bahwa berbagai bukti observasional dari V1504 Cyg mendukung model ketidakstabilan termal-pasang untuk superletupan bintang SU UMa. Kami menyajikan tanggapan rinci terhadap semua kritikannya dengan memberikan penjelasan yang jelas. Kami menyimpulkan bahwa pada akhirnya model ketidakstabilan termal-pasang tetap satu-satunya model yang layak untuk superletupan dan superjungkiran pada bintang SU UMa.
|
id
|
Let A be a C*-algebra and A** its enveloping von Neumann algebra. C. Akemann suggested a kind of non-commutative topology in which certain projections in A** play the role of open sets. The adjectives "open", "closed", "compact", and "relatively compact" all can be applied to projections in A**. Two operator inequalities were used by Akemann in connection with compactness. Both of these inequalities are equivalent to compactness for a closed projection in A**, but only one is equivalent to relative compactness for a general projection. A third operator inequality, also related to compactness, was used by the author. It turns out that the study of all three inequalities can be unified by considering a numerical invariant which is equivalent to the distance of a projection from the set of relatively compact projections. Since the subject concerns the relation between a projection and its closure, Tomita's concept of regularity of projections seems relevant, and some results and examples on regularity are also given. A few related results on semicontinuity are also included.
|
Sei A eine C*-Algebra und A** ihre umhüllende von Neumann-Algebra. C. Akemann schlug eine Art nichtkommutativer Topologie vor, in der bestimmte Projektionen in A** die Rolle offener Mengen spielen. Die Adjektive „offen“, „abgeschlossen“, „kompakt“ und „relativ kompakt“ können alle auf Projektionen in A** angewandt werden. Akemann verwendete zwei Operatorungleichungen im Zusammenhang mit Kompaktheit. Beide Ungleichungen sind für eine abgeschlossene Projektion in A** äquivalent zur Kompaktheit, aber nur eine ist für eine allgemeine Projektion äquivalent zur relativen Kompaktheit. Eine dritte Operatorungleichung, die ebenfalls mit Kompaktheit zusammenhängt, wurde vom Autor verwendet. Es zeigt sich, dass die Untersuchung aller drei Ungleichungen vereinheitlicht werden kann, indem man eine numerische Invariante betrachtet, die dem Abstand einer Projektion von der Menge der relativ kompakten Projektionen entspricht. Da das Thema die Beziehung zwischen einer Projektion und ihrem Abschluss betrifft, scheint T omitas Begriff der Regularität von Projektionen relevant zu sein, und einige Ergebnisse und Beispiele zur Regularität werden ebenfalls gegeben. Einige verwandte Ergebnisse über Halbstetigkeit sind ebenfalls enthalten.
|
de
|
We propose to develop a high-energy heavy-ion experimental database and make it accessible to the scientific community through an on-line interace. This database will be searchable and cross-indexed with relevant publications, including published detector descriptions. Since this database will be a community resource, it requires the high-energy nuclear physics community's financial and manpower support. This database should eventually contain all published data from the Bevalac, AGS and SPS to RHIC and LHC energies, proton-proton to nucleus-nucleus collisions as well as other relevant systems and all measured observables. Such a database would have tremendous scientific payoff as it makes systematic studies easier and allows simpler benchmarking of theoretical models to a broad range of old and new experiments. Furthermore, there is a growing need for compilations of high-energy nuclear data for applications including stockpile stewardship, technology development for intertial confinement fusion and target and source development for upcoming facilities such as the Next Linear Collider. To enhance the utility of this database, we propose periodically performing evaluations of the data and summarizing the results in topical reviews.
|
Мы предлагаем разработать базу данных экспериментов с тяжелыми ионами высокой энергии и обеспечить к ней доступ научному сообществу через онлайн-интерфейс. Эта база данных будет доступна для поиска и снабжена перекрестными ссылками на соответствующие публикации, включая описания детекторов. Поскольку данная база данных предназначена для использования сообществом, она требует финансовой и кадровой поддержки со стороны сообщества физиков высоких энергий. В конечном итоге база данных должна содержать все опубликованные данные, полученные на установках Bevalac, AGS и SPS, а также на коллайдерах RHIC и LHC, включая столкновения протон-протон, ядро-ядро, а также другие релевантные системы и все измеренные наблюдаемые величины. Такая база данных принесет значительную научную пользу, поскольку упростит проведение систематических исследований и позволит легче сопоставлять теоретические модели с широким спектром как старых, так и новых экспериментов. Кроме того, растет потребность в сборниках данных по ядерной физике высоких энергий для прикладных задач, включая обеспечение сохранности ядерных арсеналов, разработку технологий для инерционного термоядерного синтеза, а также создание мишеней и источников для будущих установок, таких как Следующий линейный коллайдер. С целью повышения полезности данной базы данных мы предлагаем периодически проводить анализ данных и публиковать результаты в виде тематических обзоров.
|
ru
|
We study periodic, quasi-periodic (Thue-Morse, Fibonacci, Period Doubling, Rudin-Shapiro), fractal (Cantor, generalized Cantor), Kolakoski and random binary sequences using a tight-binding wire model, where a site is a monomer (e.g., in DNA, a base pair). We use B-DNA as our prototype system. All sequences have purines, guanine (G) or adenine (A) on the same strand, i.e., our prototype binary alphabet is (G,A). Our aim is to examine the influence of sequence intricacy and magnitude of parameters on energy structure, localization and charge transport. We study quantities such as autocorrelation function, eigenspectra, density of states, Lyapunov exponents, transmission coefficients and current-voltage curves. We show that the degree of sequence intricacy and the presence of correlations decisively affect the aforementioned physical properties. Periodic segments have enhanced transport properties. Specifically, in homogeneous sequences transport efficiency is maximum. There are several deterministic aperiodic sequences that can support significant currents, depending on the Fermi level of the leads. Random sequences is the less efficient category.
|
ພວກເຮົາສຶກສາລຳດັບໄລຍະ, ລຳດັບເກືອບໄລຍະ (Thue-Morse, Fibonacci, Period Doubling, Rudin-Shapiro), ລຳດັບຮູບກະແຈ (Cantor, generalized Cantor), ລຳດັບ Kolakoski ແລະ ລຳດັບສຸ່ມທີ່ເປັນຖານສອງໂດຍໃຊ້ຮູບແບບເສັ້ນລວດທີ່ມີການຜູກມັດຢ່າງແໜ້ນໜາ, ໂດຍທີ່ແຕ່ລະຕຳແໜ່ງແມ່ນເປັນໂມໂນເມີ (ຕົວຢ່າງ: ໃນ DNA, ຄູ່ເບດເຊ). ພວກເຮົາໃຊ້ B-DNA ເປັນລະບົບຕົ້ນແບບ. ລຳດັບທັງໝົດມີພູຣິນ, ກຸວານິນ (G) ຫຼື ແອດີນິນ (A) ຢູ່ໃນເສັ້ນດຽວກັນ, ນັ້ນແມ່ນ ຕົວອັກສອນຖານສອງຕົ້ນແບບຂອງພວກເຮົາແມ່ນ (G,A). ເປົ້າໝາຍຂອງພວກເຮົາແມ່ນເພື່ອກວດກາຜົນກະທົບຂອງຄວາມຊັບຊ້ອນຂອງລຳດັບ ແລະ ຄວາມໃຫຍ່ຂອງພາລາມິເຕີຕໍ່ໂຄງສ້າງພະລັງງານ, ການຈັດຕັ້ງຕົວຢູ່ໃນທ້ອງຖິ່ນ ແລະ ການຂົນສົ່ງຄ່າໄຟຟ້າ. ພວກເຮົາສຶກສາປະລິມານຕ່າງໆ ເຊັ່ນ: ຟັງຊັ້ນການເຊື່ອມຕໍ່ຕົວມັນເອງ, ສະເປັກຕຼັມຄ່າລັກສະນະ, ຄວາມໜາແໜ້ນຂອງສະຖານະ, ຄ່າເລກຂອງ Lyapunov, ສຳປະສິດການຖ່າຍໂອນ ແລະ ເສັ້ນໂຄ້ງກະແສໄຟຟ້າຕໍ່ຄວາມຕ້ານທານ. ພວກເຮົາສະແດງໃຫ້ເຫັນວ່າລະດັບຄວາມຊັບຊ້ອນຂອງລຳດັບ ແລະ ການມີຢູ່ຂອງຄວາມສຳພັນມີຜົນກະທົບຢ່າງຕັດສິນໃຈຕໍ່ຄຸນສົມບັດທາງດ້ານຮ່າງກາຍທີ່ກ່າວມາຂ້າງເທິງ. ລຳດັບໄລຍະມີຄຸນສົມບັດການຂົນສົ່ງທີ່ດີຂຶ້ນ. ໂດຍສະເພາະ, ໃນລຳດັບທີ່ເປັນເນື້ອດຽວກັນ, ປະສິດທິພາບການຂົນສົ່ງແມ່ນສູງສຸດ. ມີຫຼາຍລຳດັບທີ່ບໍ່ເປັນໄລຍະແຕ່ກຳນົດໄດ້ທີ່ສາມາດຮັບຮອງກະແສໄຟຟ້າທີ່ສຳຄັນໄດ້, ຂຶ້ນກັບລະດັບເຟີມີຂອງຂັ້ວຕໍ່. ລຳດັບສຸ່ມແມ່ນກຸ່ມທີ່ມີປະສິດທິພາບຕ່ຳທີ່ສຸດ.
|
lo
|
A recent publication provides the network graph for a neocortical microcircuit comprising 8 million connections between 31,000 neurons (H. Markram, et al., Reconstruction and simulation of neocortical microcircuitry, Cell, 163 (2015) no. 2, 456-492). Since traditional graph-theoretical methods may not be sufficient to understand the immense complexity of such a biological network, we explored whether methods from algebraic topology could provide a new perspective on its structural and functional organization. Structural topological analysis revealed that directed graphs representing connectivity among neurons in the microcircuit deviated significantly from different varieties of randomized graph. In particular, the directed graphs contained in the order of $10^7$ simplices {\DH} groups of neurons with all-to-all directed connectivity. Some of these simplices contained up to 8 neurons, making them the most extreme neuronal clustering motif ever reported. Functional topological analysis of simulated neuronal activity in the microcircuit revealed novel spatio-temporal metrics that provide an effective classification of functional responses to qualitatively different stimuli. This study represents the first algebraic topological analysis of structural connectomics and connectomics-based spatio-temporal activity in a biologically realistic neural microcircuit. The methods used in the study show promise for more general applications in network science.
|
توفر إحدى المنشورات الحديثة رسمًا بيانيًا لشبكة دارة دماغية دانية تضم 8 ملايين اتصال بين 31,000 عصبون (H. Markram وآخرون، إعادة بناء ومحاكاة الدارة الدماغية الدانية، Cell، 163 (2015) العدد 2، 456-492). وبما أن الطرق التقليدية في نظرية الرسوم البيانية قد لا تكون كافية لفهم التعقيد الهائل لهذه الشبكة البيولوجية، فقد بحثنا فيما إذا كانت الطرق المستمدة من الطوبولوجيا الجبرية يمكن أن تقدم منظورًا جديدًا حول تنظيمها البنيوي والوظيفي. كشف التحليل الطوبولوجي البنيوي أن الرسوم البيانية الموجهة التي تمثل التوصيل بين العصبونات في الدارة الدمية تختلف بشكل كبير عن أنواع مختلفة من الرسوم البيانية العشوائية. وعلى وجه الخصوص، احتوت الرسوم البيانية الموجهة على ترتيب من $10^7$ سيمبليكس (simplexes) – وهي مجموعات من العصبونات ذات اتصال موجه من كل إلى كل. وضمت بعض هذه السيمبليكس ما يصل إلى 8 عصبونات، ما يجعلها أكثر عناصر التجمع العصبي تطرفًا التي تم الإبلاغ عنها حتى الآن. كما كشف التحليل الطوبولوجي الوظيفي للنشاط العصبي المحاكي في الدارة الدمية عن مقاييس مكانية-زمنية جديدة توفر تصنيفًا فعّالًا للاستجابات الوظيفية لأنواع مختلفة نوعيًا من المحفزات. يُمثّل هذا البحث أول تحليل طوبولوجي جبري للبنية التوصيلية (connectomics) والنشاط المكاني-الزماني القائم على التوصيل في دارة عصبية دمية واقعية بيولوجيًا. وتُظهر الطرق المستخدمة في الدراسة إمكانات واعدة لتطبيقات أكثر عمومية في علم الشبكات.
|
ar
|
The advantages of adaptivity and feedback are of immense interest in signal processing and communication with many positive and negative results. Although it is established that adaptivity does not offer substantial reductions in minimax mean square error for a fixed number of measurements, existing results have shown several advantages of adaptivity in complexity of reconstruction, accuracy of support detection, and gain in signal-to-noise ratio, under constraints on sensing energy. Sensing energy has often been measured in terms of the Frobenius Norm of the sensing matrix. This paper uses a different metric that we call the $l_0$ cost of a sensing matrix-- to quantify the complexity of sensing. Thus sparse sensing matrices have a lower cost. We derive information-theoretic lower bounds on the $l_0$ cost that hold for any non-adaptive sensing strategy. We establish that any non-adaptive sensing strategy must incur an $l_0$ cost of $\Theta\left( N \log_2(N)\right) $ to reconstruct an $N$-dimensional, one--sparse signal when the number of measurements are limited to $\Theta\left(\log_2 (N)\right)$. In comparison, bisection-type adaptive strategies only require an $l_0$ cost of at most $\mathcal{O}(N)$ for an equal number of measurements. The problem has an interesting interpretation as a sphere packing problem in a multidimensional space, such that all the sphere centres have minimum non-zero co-ordinates. We also discuss the variation in $l_0$ cost as the number of measurements increase from $\Theta\left(\log_2 (N)\right)$ to $\Theta\left(N\right)$.
|
Uyarlanabilirlik ve geri bildirimin avantajları, birçok olumlu ve olumsuz sonuçla birlikte sinyal işleme ve iletişimde büyük ilgi görmektedir. Uyarlanabilirliğin sabit sayıda ölçüm için minimaks ortalama kare hatasında önemli azalmalar sağlamadığı bilinmekle birlikte, mevcut sonuçlar, algılama enerjisi üzerinde kısıtlamalar varken, uyarlanabilirliğin yeniden yapılandırma karmaşıklığı, destek tespitinde doğruluk ve sinyal-gürültü oranında kazanç açısından çeşitli avantajlarını göstermiştir. Algılama enerjisi genellikle algılama matrisinin Frobenius Normu cinsinden ölçülmüştür. Bu makalede, algılama karmaşıklığını ölçmek için algılama matrisinin $l_0$ maliyeti olarak adlandırdığımız farklı bir metrik kullanılmaktadır. Böylece seyrek algılama matrislerinin daha düşük maliyeti vardır. Herhangi bir uyarlanabilir olmayan algılama stratejisi için geçerli olan $l_0$ maliyeti üzerine bilgi-teorik alt sınırlar türetilmiştir. Ölçüm sayısı $\Theta\left(\log_2 (N)\right)$ ile sınırlı olduğunda, $N$ boyutlu, bir-sparse bir sinyalin yeniden oluşturulması için herhangi bir uyarlanabilir olmayan algılama stratejisinin $\Theta\left( N \log_2(N)\right)$ büyüklüğünde bir $l_0$ maliyeti ödemesi gerektiği gösterilmiştir. Buna karşılık, bisection-tipi uyarlanabilir stratejiler eşit sayıda ölçüm için en fazla $\mathcal{O}(N)$ büyüklüğünde bir $l_0$ maliyeti gerektirmektedir. Problem, tüm küre merkezlerinin sıfırdan farklı minimum koordinatlara sahip olduğu çok boyutlu bir uzayda bir küre paketleme problemi olarak ilginç bir yorumu vardır. Ayrıca, ölçüm sayısı $\Theta\left(\log_2 (N)\right)$'dan $\Theta\left(N\right)$'a artarken $l_0$ maliyetindeki değişimi de tartışıyoruz.
|
tr
|
We expose some simple facts at the interplay between mathematics and the real world, putting in evidence mathematical objects " nonlinear generalized functions" that are needed to model the real world, which appear to have been generally neglected up to now by mathematicians. Then we describe how a "nonlinear theory of generalized functions" was obtained inside the Leopoldo Nachbin group of infinite dimensional holomorphy between 1980 and 1985. This new theory permits to multiply arbitrary distributions and contains the above mathematical objects, which shows that the features of this theory are natural and unavoidable for a mathematical description of the real world. Finally we present direct applications of the theory such as existence-uniqueness for systems of PDEs without classical solutions and calculations of shock waves for systems in non-divergence form done between 1985 and 1995, for which we give three examples of different nature: elasticity, cosmology, multifluid flows.
|
Expomos alguns fatos simples sobre a interação entre a matemática e o mundo real, destacando objetos matemáticos — "funções generalizadas não lineares" — necessários para modelar o mundo real, que parecem ter sido geralmente negligenciados até agora pelos matemáticos. Em seguida, descrevemos como uma "teoria não linear de funções generalizadas" foi obtida dentro do grupo de holomorfia de dimensão infinita de Leopoldo Nachbin entre 1980 e 1985. Essa nova teoria permite multiplicar distribuições arbitrárias e contém os objetos matemáticos acima mencionados, o que mostra que as características dessa teoria são naturais e inevitáveis para uma descrição matemática do mundo real. Finalmente, apresentamos aplicações diretas da teoria, como existência e unicidade para sistemas de EDPs sem soluções clássicas e cálculos de ondas de choque para sistemas em forma não divergente realizados entre 1985 e 1995, para os quais damos três exemplos de natureza diferente: elasticidade, cosmologia, escoamentos multifásicos.
|
pt
|
Superfluidity and superconductivity are remarkable manifestations of quantum coherence at a macroscopic scale. The dynamics of superfluids has dominated the study of these systems for decades now, but a comprehensive theoretical framework is still lacking. We introduce a local extension of the time-dependent density functional theory to describe the dynamics of fermionic superfluids. Within this approach one can correctly represent vortex quantization, generation, and dynamics, the transition from a superfluid to a normal phase and a number of other large amplitude collective modes which are beyond the scope of two-fluid hydrodynamics, Ginzburg-Landau and/or Gross-Pitaevskii approaches. We illustrate the power of this approach by studying the generation of quantized vortices, vortex rings, vortex reconnection, and transition from a superfluid to a normal state in real time for a unitary Fermi gas. We predict the emergence of a new qualitative phenomenon in superfluid dynamics of gases, the existence of stable superfluidity when the systems are stirred with velocities significantly exceeding the nominal Landau critical velocity in these systems.
|
La superfluidità e la superconduttività sono manifestazioni notevoli della coerenza quantistica su scala macroscopica. Lo studio della dinamica dei superfluidi ha dominato la ricerca in questi sistemi per decenni, ma a tutt'oggi manca un quadro teorico completo. Introduciamo un'estensione locale della teoria funzionale della densità dipendente dal tempo per descrivere la dinamica dei superfluidi fermionici. Mediante questo approccio è possibile rappresentare correttamente la quantizzazione dei vortici, la loro generazione e dinamica, la transizione da uno stato superfluido a uno normale e un certo numero di altre modalità collettive di grande ampiezza che esulano dall'ambito della idrodinamica a due fluidi, degli approcci di Ginzburg-Landau e/o di Gross-Pitaevskii. Illustreremo la potenza di questo approccio analizzando in tempo reale la generazione di vortici quantizzati, anelli di vortice, la riconnessione di vortici e la transizione da uno stato superfluido a uno normale in un gas di Fermi unitario. Prevediamo l'emergere di un nuovo fenomeno qualitativo nella dinamica superfluida dei gas, ovvero l'esistenza di una superfluidità stabile quando i sistemi vengono agitati con velocità significativamente superiori alla velocità critica nominale di Landau in questi sistemi.
|
it
|
In echocardiography (echo), an electrocardiogram (ECG) is conventionally used to temporally align different cardiac views for assessing critical measurements. However, in emergencies or point-of-care situations, acquiring an ECG is often not an option, hence motivating the need for alternative temporal synchronization methods. Here, we propose Echo-SyncNet, a self-supervised learning framework to synchronize various cross-sectional 2D echo series without any external input. The proposed framework takes advantage of both intra-view and inter-view self supervisions. The former relies on spatiotemporal patterns found between the frames of a single echo cine and the latter on the interdependencies between multiple cines. The combined supervisions are used to learn a feature-rich embedding space where multiple echo cines can be temporally synchronized. We evaluate the framework with multiple experiments: 1) Using data from 998 patients, Echo-SyncNet shows promising results for synchronizing Apical 2 chamber and Apical 4 chamber cardiac views; 2) Using data from 3070 patients, our experiments reveal that the learned representations of Echo-SyncNet outperform a supervised deep learning method that is optimized for automatic detection of fine-grained cardiac phase; 3) We show the usefulness of the learned representations in a one-shot learning scenario of cardiac keyframe detection. Without any fine-tuning, keyframes in 1188 validation patient studies are identified by synchronizing them with only one labeled reference study. We do not make any prior assumption about what specific cardiac views are used for training and show that Echo-SyncNet can accurately generalize to views not present in its training set. Project repository: github.com/fatemehtd/Echo-SyncNet.
|
الٹراساؤنڈ کارڈیوگرافی (اِکو) میں، مختلف دل کے مناظر کو وقتی طور پر ہم آہنگ کرنے اور اہم پیمائشوں کا اندازہ لگانے کے لیے معمول کے مطابق الیکٹروکارڈیوگرام (ECG) کا استعمال کیا جاتا ہے۔ تاہم، ہنگامی یا نگہداشت کے مقامات پر صورتحال میں، ECG حاصل کرنا اکثر ممکن نہیں ہوتا، جس کی وجہ سے وقتی ہم آہنگی کے متبادل طریقوں کی ضرورت پیش آتی ہے۔ یہاں ہم "اِکو-سنک نیٹ" کا تجویز کرتے ہیں، جو کسی بیرونی اندراج کے بغیر مختلف تراششی 2D اِکو سیریز کو ہم آہنگ کرنے کے لیے خود نگرانی شدہ سیکھنے کا ایک ڈھانچہ ہے۔ تجویز کردہ ڈھانچہ اندرونی منظر (انٹرا ویو) اور مناظر کے درمیان (انٹر ویو) دونوں خود نگرانیوں کا فائدہ اٹھاتا ہے۔ پہلی ایک اکیلے اِکو سائن میں فریموں کے درمیان پائے جانے والے مکان-وقتی نمونوں پر منحصر ہوتی ہے، جبکہ دوسری متعدد سائن کے درمیان باہمی تعلقات پر منحصر ہوتی ہے۔ اس طرح کی امتزاجی نگرانی کا استعمال متعدد اِکو سائن کو وقتی طور پر ہم آہنگ کرنے کے لیے ایک خصوصیت سے بھرپور ایمبیڈنگ جگہ سیکھنے کے لیے کیا جاتا ہے۔ ہم اس ڈھانچے کا اندازہ کئی تجربات کے ذریعے لگاتے ہیں: 1) 998 مریضوں کے ڈیٹا کا استعمال کرتے ہوئے، اِکو-سنک نیٹ ایپیکل 2 کیمرہ اور ایپیکل 4 کیمرہ دل کے مناظر کو ہم آہنگ کرنے میں امید افزا نتائج دکھاتا ہے؛ 2) 3070 مریضوں کے ڈیٹا کا استعمال کرتے ہوئے، ہمارے تجربات ظاہر کرتے ہیں کہ اِکو-سنک نیٹ کے سیکھے گئے تصورات ایک نگرانی شدہ گہری سیکھنے والی طریقہ کار پر بھاری ہیں، جو باریک دل کے مرحلے کی خودکار تشخیص کے لیے بہترین ہے؛ 3) ہم دل کے کلیدی فریم کی تشخیص کے ایک شاٹ سیکھنے کے منظر نامے میں سیکھے گئے تصورات کی افادیت کو دکھاتے ہیں۔ بغیر کسی مزید ایڈجسٹمنٹ کے، صرف ایک لیبل شدہ حوالہ مطالعہ کے ساتھ ہم آہنگ کرکے 1188 تصدیق شدہ مریض مطالعات میں کلیدی فریم کی نشاندہی کی جاتی ہے۔ ہم تربیت کے لیے استعمال ہونے والے مخصوص دل کے مناظر کے بارے میں کوئی ابتدائی فرض نہیں کرتے اور یہ دکھاتے ہیں کہ اِکو-سنک نیٹ اپنے تربیتی سیٹ میں موجود نہ ہونے والے مناظر تک درست طریقے سے توسیع کر سکتا ہے۔ منصوبہ ریپوزیٹری: github.com/fatemehtd/Echo-SyncNet۔
|
ur
|
A recent publication provides the network graph for a neocortical microcircuit comprising 8 million connections between 31,000 neurons (H. Markram, et al., Reconstruction and simulation of neocortical microcircuitry, Cell, 163 (2015) no. 2, 456-492). Since traditional graph-theoretical methods may not be sufficient to understand the immense complexity of such a biological network, we explored whether methods from algebraic topology could provide a new perspective on its structural and functional organization. Structural topological analysis revealed that directed graphs representing connectivity among neurons in the microcircuit deviated significantly from different varieties of randomized graph. In particular, the directed graphs contained in the order of $10^7$ simplices {\DH} groups of neurons with all-to-all directed connectivity. Some of these simplices contained up to 8 neurons, making them the most extreme neuronal clustering motif ever reported. Functional topological analysis of simulated neuronal activity in the microcircuit revealed novel spatio-temporal metrics that provide an effective classification of functional responses to qualitatively different stimuli. This study represents the first algebraic topological analysis of structural connectomics and connectomics-based spatio-temporal activity in a biologically realistic neural microcircuit. The methods used in the study show promise for more general applications in network science.
|
Недавно опубликованная работа представляет граф сети нейокортикальной микросхемы, включающей 8 миллионов соединений между 31 000 нейронами (H. Markram и др., Reconstruction and simulation of neocortical microcircuitry, Cell, 163 (2015), № 2, 456–492). Поскольку традиционные методы теории графов могут оказаться недостаточными для понимания огромной сложности такой биологической сети, мы исследовали, могут ли методы алгебраической топологии предложить новый взгляд на её структурную и функциональную организацию. Структурный топологический анализ показал, что ориентированные графы, представляющие связность между нейронами в микросхеме, существенно отличаются от различных видов рандомизированных графов. В частности, ориентированные графы содержали порядка $10^7$ симплексов — групп нейронов с полной направленной связностью (все-со-всеми). Некоторые из этих симплексов включали до 8 нейронов, что делает их наиболее выраженным мотивом нейронного кластерирования, когда-либо описанным. Функциональный топологический анализ моделируемой нейронной активности в микросхеме выявил новые пространственно-временные метрики, позволяющие эффективно классифицировать функциональные реакции на качественно различные стимулы. Данное исследование представляет собой первый пример алгебраического топологического анализа структурной коннектомики и основанной на коннектомике пространственно-временной активности в биологически реалистичной нейронной микросхеме. Использованные в исследовании методы демонстрируют перспективность для более широкого применения в науке о сетях.
|
ru
|
Let A be a C*-algebra and A** its enveloping von Neumann algebra. C. Akemann suggested a kind of non-commutative topology in which certain projections in A** play the role of open sets. The adjectives "open", "closed", "compact", and "relatively compact" all can be applied to projections in A**. Two operator inequalities were used by Akemann in connection with compactness. Both of these inequalities are equivalent to compactness for a closed projection in A**, but only one is equivalent to relative compactness for a general projection. A third operator inequality, also related to compactness, was used by the author. It turns out that the study of all three inequalities can be unified by considering a numerical invariant which is equivalent to the distance of a projection from the set of relatively compact projections. Since the subject concerns the relation between a projection and its closure, Tomita's concept of regularity of projections seems relevant, and some results and examples on regularity are also given. A few related results on semicontinuity are also included.
|
لتكن A جبر سي-نجمة وA** هو جبر فون نيومان المُحيط به. اقترح C. أكيمانن نوعًا من الطوبولوجيا غير التبادلية حيث تؤدي بعض المساقط في A** دور المجموعات المفتوحة. يمكن تطبيق الصفات "مفتوح"، "مغلق"، "مدمج"، و"مدمج نسبيًا" على المساقط في A**. استخدم أكيمانن متراجعتين عدديتين فيما يتعلق بالمدمجية. كلتاهما تعادلان المدمجية بالنسبة لمسقط مغلق في A**، ولكن إحداهما فقط تعادل المدمجية النسبية بالنسبة لمسقط عام. استخدم الكاتب متراجعة عددية ثالثة مرتبطة أيضًا بالمدمجية. يتضح أن دراسة هذه المتراجحات الثلاث يمكن توحيدُها من خلال النظر إلى متغير عددي يعادل المسافة بين مسقط ومجموعة المساقط المدمجة نسبيًا. وبما أن الموضوع يتناول العلاقة بين مسقط وإغلاقه، فإن مفهوم توميتا للانتظام في المساقط يبدو ذا صلة، ويُقدَّم أيضًا بعض النتائج والأمثلة حول الانتظام. كما تُضمَّن عدد قليل من النتائج ذات الصلة بالشبه استمرارية.
|
ar
|
We derive mass functions (MF) for halo red dwarfs (the faintest hydrogen burning stars) and then extrapolate to place limits on the total mass of halo brown dwarfs (stars not quite massive enough to burn hydrogen). The mass functions are obtained from the luminosity function of a sample of 114 local halo stars in the USNO parallax survey (Dahn \etal 1995). We use stellar models of Alexander \etal (1996) and make varying assumptions about metallicity and about possible unresolved binaries in the sample. We find that the MF for halo red dwarfs cannot rise more quickly than $1/m^2$ as one approaches the hydrogen burning limit. Using recent results from star formation theory, we extrapolate the MF into the brown-dwarf regime. We see that likely extrapolations imply that the total mass of brown dwarfs in the halo is less than $\sim 3\%$ of the local mass density of the halo ($\sim 0.3\%$ for the more realistic models we consider). Our limits apply to brown dwarfs in the halo that come from the same stellar population as the red dwarfs.
|
Chúng tôi xác định các hàm khối lượng (MF) đối với các sao lùn đỏ vành đai (những ngôi sao đốt hydro mờ nhất) và sau đó ngoại suy để đặt giới hạn tổng khối lượng của các sao lùn nâu vành đai (những ngôi sao không đủ khối lượng để đốt hydro). Các hàm khối lượng được lấy từ hàm độ sáng của một mẫu gồm 114 ngôi sao vành đai gần Trái Đất trong khảo sát thị sai USNO (Dahn \etal 1995). Chúng tôi sử dụng các mô hình sao của Alexander \etal (1996) và đưa ra các giả định khác nhau về kim loại học và về khả năng tồn tại các cặp sao chưa phân giải trong mẫu. Chúng tôi nhận thấy rằng hàm khối lượng đối với các sao lùn đỏ vành đai không thể tăng nhanh hơn $1/m^2$ khi tiến gần đến giới hạn đốt hydro. Sử dụng các kết quả gần đây từ lý thuyết hình thành sao, chúng tôi ngoại suy hàm khối lượng vào vùng sao lùn nâu. Chúng tôi thấy rằng các phép ngoại suy hợp lý cho thấy tổng khối lượng các sao lùn nâu trong vành đai nhỏ hơn $\sim 3\%$ mật độ khối lượng địa phương của vành đai ($\sim 0.3\%$ đối với các mô hình thực tế hơn mà chúng tôi xét). Các giới hạn của chúng tôi áp dụng cho các sao lùn nâu trong vành đai bắt nguồn từ cùng một quần thể sao như các sao lùn đỏ.
|
vi
|
Kundt spacetimes are of great importance in general relativity in 4 dimensions and have a number of topical applications in higher dimensions in the context of string theory. The degenerate Kundt spacetimes have many special and unique mathematical properties, including their invariant curvature structure and their holonomy structure. We provide a rigorous geometrical kinematical definition of the general Kundt spacetime in 4 dimensions; essentially a Kundt spacetime is defined as one admitting a null vector that is geodesic, expansion-free, shear-free and twist-free. A Kundt spacetime is said to be degenerate if the preferred kinematic and curvature null frames are all aligned. The degenerate Kundt spacetimes are the only spacetimes in 4 dimensions that are not $\mathcal{I}$-non-degenerate, so that they are not determined by their scalar polynomial curvature invariants. We first discuss the non-aligned Kundt spacetimes, and then turn our attention to the degenerate Kundt spacetimes. The degenerate Kundt spacetimes are classified algebraically by the Riemann tensor and its covariant derivatives in the aligned kinematic frame; as an example, we classify Riemann type D degenerate Kundt spacetimes in which $\nabla(Riem),\nabla^{(2)}(Riem)$ are also of type D. We discuss other local characteristics of the degenerate Kundt spacetimes. Finally, we discuss degenerate Kundt spacetimes in higher dimensions.
|
Các không-thời gian Kundt có tầm quan trọng lớn trong thuyết tương đối tổng quát bốn chiều và có một số ứng dụng nổi bật trong các chiều cao hơn trong bối cảnh lý thuyết dây. Các không-thời gian Kundt suy biến có nhiều tính chất toán học đặc biệt và độc đáo, bao gồm cấu trúc độ cong bất biến và cấu trúc nhóm holonomy của chúng. Chúng tôi đưa ra một định nghĩa động học hình học chặt chẽ cho không-thời gian Kundt tổng quát trong bốn chiều; về cơ bản, một không-thời gian Kundt được định nghĩa là không-thời gian cho phép tồn tại một véctơ nul là đường trắc địa, không giãn nở, không cắt và không xoắn. Một không-thời gian Kundt được gọi là suy biến nếu các cơ sở nul động học và độ cong ưu tiên đều cùng phương. Các không-thời gian Kundt suy biến là những không-thời gian duy nhất trong bốn chiều không phải là $\mathcal{I}$-không suy biến, do đó chúng không được xác định bởi các bất biến đa thức vô hướng của độ cong. Trước tiên, chúng tôi thảo luận về các không-thời gian Kundt không cùng phương, sau đó tập trung vào các không-thời gian Kundt suy biến. Các không-thời gian Kundt suy biến được phân loại đại số theo tenxơ Riemann và các đạo hàm hiệp biến của nó trong cơ sở động học cùng phương; làm ví dụ, chúng tôi phân loại các không-thời gian Kundt suy biến kiểu D theo Riemann, trong đó $\nabla(Riem)$ và $\nabla^{(2)}(Riem)$ cũng có kiểu D. Chúng tôi thảo luận thêm về các đặc trưng địa phương khác của các không-thời gian Kundt suy biến. Cuối cùng, chúng tôi thảo luận về các không-thời gian Kundt suy biến trong các chiều cao hơn.
|
vi
|
We describe the generalized kappa-deformations of D=4 relativistic symmetries with finite masslike deformation parameter kappa and an arbitrary direction in kappa-deformed Minkowski space being noncommutative. The corresponding bicovariant differential calculi on kappa-deformed Minkowski spaces are considered. Two distinguished cases are discussed: 5D noncommutative differential calculus (kappa-deformation in time-like or space-like direction), and 4D noncommutative differential calculus having the classical dimension (noncommutative kappa-deformation in light-like direction). We introduce also left and right vector fields acting on functions of noncommutative Minkowski coordinates, and describe the noncommutative differential realizations of kappa-deformed Poincare algebra. The kappa-deformed Klein-Gordon field on noncommutative Minkowski space with noncommutative time (standard kappa-deformation) as well as noncommutative null line (light-like kappa-deformation) are discussed. Following our earlier proposal (see {1,2]) we introduce an equivalent framework replacing the local noncommutative field theory by the nonlocal commutative description with suitable nonlocal star product multiplication rules. The modification of Pauli--Jordan commutator function is described and the kappa-dependence of its light-cone behaviour in coordinate space is explicitly given. The problem with the kappa-deformed energy- momentum conservation law is recalled.
|
Біз қозғалыс бағыты кездейсоқ болып табылатын және көпмүшелік емес болып келетін каппа-деформацияланған Минковский кеңістігіндегі қозғалыс шамасына ұқсас деформациялық параметрі каппа болып келетін D=4 салыстырмалы симметриялардың жалпыланған каппа-деформацияларын сипаттаймыз. Сәйкес келетін каппа-деформацияланған Минковский кеңістігіндегі екі ковариантты дифференциалдық есептеулер қарастырылған. Екі бөлек жағдай талқыланады: 5 өлшемді көпмүшелік емес дифференциалдық есептеу (уақыт-ұқсас немесе кеңістік-ұқсас бағыттағы каппа-деформация) және классикалық өлшемге ие болатын 4 өлшемді көпмүшелік емес дифференциалдық есептеу (жарық-ұқсас бағыттағы көпмүшелік емес каппа-деформация). Біз сондай-ақ көпмүшелік емес Минковский координаталарының функцияларына әсер ететін сол және оң векторлық өрістерді енгіземіз және каппа-деформацияланған Пуанкаре алгебрасының көпмүшелік емес дифференциалдық нақтылауларын сипаттаймыз. Көпмүшелік емес уақытқа ие болатын көпмүшелік емес Минковский кеңістігіндегі каппа-деформацияланған Клейн-Гордон өрісі (стандартты каппа-деформация) сондай-ақ көпмүшелік емес нөлдік сызықта (жарық-ұқсас каппа-деформация) талқыланады. Біз бұрандамалы ұсынысымызға сүйене отырып (қараңыз {1,2]) жергілікті көпмүшелік емес өріс теориясын тиісті көпмүшелік емес жұлдызды көбейту ережелері бар жергілікті емес коммутативті сипаттамамен ауыстыратын эквивалентті нысанды енгіземіз. Паули--Жордан коммутаторлық функциясының өзгеруі сипатталады және оның координаталық кеңістіктегі жарық конусы тәрізді мінез-құлықтағы каппаға тәуелділігі нақты көрсетілген. Каппа-деформацияланған энергия-импульс сақталу заңы мәселесі еске түсіріледі.
|
kk
|
We expose some simple facts at the interplay between mathematics and the real world, putting in evidence mathematical objects " nonlinear generalized functions" that are needed to model the real world, which appear to have been generally neglected up to now by mathematicians. Then we describe how a "nonlinear theory of generalized functions" was obtained inside the Leopoldo Nachbin group of infinite dimensional holomorphy between 1980 and 1985. This new theory permits to multiply arbitrary distributions and contains the above mathematical objects, which shows that the features of this theory are natural and unavoidable for a mathematical description of the real world. Finally we present direct applications of the theory such as existence-uniqueness for systems of PDEs without classical solutions and calculations of shock waves for systems in non-divergence form done between 1985 and 1995, for which we give three examples of different nature: elasticity, cosmology, multifluid flows.
|
我々は、数学と現実世界の相互作用においていくつかの単純な事実を明らかにし、現実世界をモデル化するために必要なが、これまで数学者たちによって広く無視されてきた「非線形一般関数」という数学的対象を浮き彫りにする。次に、1980年から1985年にかけて、無限次元正則性に関するレオポルド・ナッチビンのグループ内で「非線形一般関数の理論」がどのように構築されたかを述べる。この新しい理論は、任意の分布を乗算することを可能にし、上記の数学的対象を含んでいるため、この理論の特徴が現実世界の数学的記述にとって自然かつ不可避であることが示される。最後に、1985年から1995年にかけて行われた、古典的解を持たない偏微分方程式系に対する解の存在一意性や、発散形式でない系における衝撃波の計算といった理論の直接的な応用について述べる。その応用例として、弾性論、宇宙論、多流体流れという性質の異なる3つの例を示す。
|
ja
|
In quantum computation, information is processed by gates that must coherently couple separate qubits. In many systems the qubits are naturally coupled, but such an always-on interaction limits the algorithms that may be implemented. Coupling interactions may also be directed in devices and circuits that are provided with additional control wiring. This can be achieved by adjusting the gate voltage in a semiconductor device or an additional flux in a superconducting device. Such control signals must be applied adiabatically (limiting the speed) and the additional wiring provides pathways for noise, which leads to decoherence. Here we demonstrate an alternative approach to coupling by exploiting the nonlinear behaviour of a degenerately doped silicon transistor. A single transistor can exhibit a large number of individual resonances, which are seen as changes in the source-drain current of a dc-biased device. These resonances may be addressed in frequency space due to their high quality factors. Two widely separated resonances are addressed and coupled in three-frequency spectroscopy by ensuring that the third frequency corresponds to the difference between the two individual resonances. The nonlinearity causes the generation of additional driving signals with appropriate frequency and phase relationships to ensure coupling, resulting in additional spectroscopic features that could be exploited for rapid state manipulation and gate operations.
|
ในการประมวลผลเชิงควอนตัม ข้อมูลถูกประมวลผลโดยเกตซึ่งต้องเชื่อมโยงคิวบิตที่แยกจากกันอย่างสอดคล้องกัน ระบบหลายระบบมีคิวบิตที่เชื่อมต่อกันโดยธรรมชาติ แต่การมีปฏิสัมพันธ์ที่เปิดอยู่ตลอดเวลานี้จำกัดอัลกอริธึมที่สามารถนำไปใช้งานได้ การมีปฏิสัมพันธ์ในการเชื่อมต่ออาจถูกควบคุมทิศทางได้ในอุปกรณ์และวงจรที่มีสายควบคุมเพิ่มเติม ซึ่งสามารถทำได้โดยการปรับแรงดันเกตในอุปกรณ์กึ่งตัวนำ หรือการปรับฟลักซ์เพิ่มเติมในอุปกรณ์ซุปเปอร์คอนดักเตอร์ อย่างไรก็ตาม สัญญาณควบคุมเหล่านี้จำเป็นต้องถูกใช้งานอย่างปรับตัวช้า (adiabatically) ซึ่งจำกัดความเร็ว และสายควบคุมเพิ่มเติมนี้ยังเป็นช่องทางให้เกิดสัญญาณรบกวน ซึ่งนำไปสู่การสูญเสียความสอดคล้อง (decoherence) ในที่นี้ เราได้แสดงแนวทางทางเลือกในการเชื่อมต่อ โดยอาศัยพฤติกรรมไม่เป็นเชิงเส้นของทรานซิสเตอร์ซิลิคอนที่ถูกโดปอย่างถึงขีดสุด ทรานซิสเตอร์ตัวเดียวสามารถแสดงการสั่นพ้องจำนวนมาก ซึ่งสังเกตได้จากการเปลี่ยนแปลงของกระแสซอร์ส-เดรนในอุปกรณ์ที่มีแรงดันคงที่ การสั่นพ้องเหล่านี้สามารถถูกกำหนดเป้าหมายในโดเมนความถี่ได้ เนื่องจากมีค่าคุณภาพ (quality factor) สูง เราได้กำหนดเป้าหมายและเชื่อมโยงการสั่นพ้องสองชุดที่ห่างกันมาก โดยใช้สเปกโทรสโกปีสามความถี่ โดยมั่นใจว่าความถี่ที่สามตรงกับผลต่างของความถี่การสั่นพ้องทั้งสอง การไม่เป็นเชิงเส้นทำให้เกิดสัญญาณขับเคลื่อนเพิ่มเติมที่มีความถี่และสัมพันธ์เฟสที่เหมาะสม เพื่อให้เกิดการเชื่อมต่อ ส่งผลให้เกิดลักษณะเฉพาะด้านสเปกโทรสโกปีเพิ่มเติม ซึ่งสามารถนำมาใช้ประโยชน์ในการควบคุมสถานะอย่างรวดเร็วและการดำเนินการเกต
|
th
|
A critical discussion of the present status of the CERN experiments on charm dynamics and hadron collective flow is given. We emphasize the importance of the flow excitation function from 1 to 50 A$\cdot$GeV: here the hydrodynamic model has predicted the collapse of the $v_1$-flow and of the $v_2$-flow at $\sim 10$ A$\cdot$GeV; at 40 A$\cdot$GeV it has been recently observed by the NA49 collaboration. Since hadronic rescattering models predict much larger flow than observed at this energy we interpret this observation as potential evidence for a first order phase transition at high baryon density $\rho_B$. A detailed discussion of the collective flow as a barometer for the equation of state (EoS) of hot dense matter at RHIC follows. Additionally, detailed transport studies show that the away-side jet suppression can only partially ($<$ 50%) be due to hadronic rescattering. We, finally, propose upgrades and second generation experiments at RHIC which inspect the first order phase transition in the fragmentation region, i.e. at $\mu_B \approx 400$ MeV ($y \approx 4-5$), where the collapse of the proton flow should be seen in analogy to the 40 A$\cdot$GeV data. The study of Jet-Wake-riding potentials and Bow shocks -- caused by jets in the QGP formed at RHIC -- can give further information on the equation of state (EoS) and transport coefficients of the Quark Gluon Plasma (QGP).
|
Ibinigay ang isang mahigpit na talakayan tungkol sa kasalukuyang kalagayan ng mga eksperimento ng CERN sa charm dynamics at hadron collective flow. Binibigyang-diin namin ang kahalagahan ng flow excitation function mula 1 hanggang 50 A$\cdot$GeV: dito, ang hydrodynamic model ay naka-predict ng pagbagsak ng $v_1$-flow at ng $v_2$-flow sa paligid ng 10 A$\cdot$GeV; noong kamakailan ay obserbado ito ng samahan na NA49 sa 40 A$\cdot$GeV. Dahil ang mga hadronic rescattering model ay naka-predict ng mas malaking flow kaysa sa obserbado sa enerhiyang ito, aming interpretasyon ay ang obserbasyong ito ay posibleng ebidensya para sa isang first order phase transition sa mataas na baryon density $\rho_B$. Susunod ay isang detalyadong talakayan tungkol sa collective flow bilang isang barometer para sa equation of state (EoS) ng mainit at masiksik na bagay sa RHIC. Bukod dito, ang mga detalyadong transport studies ay nagpapakita na ang away-side jet suppression ay maaari lamang mapaliwanag nang bahagyang ($<$ 50%) dahil sa hadronic rescattering. Sa huli, iminumungkahi namin ang mga upgrade at eksperimento ng ikalawang henerasyon sa RHIC na susuriin ang first order phase transition sa fragmentation region, i.e. sa $\mu_B \approx 400$ MeV ($y \approx 4-5$), kung saan ang pagbagsak ng proton flow ay dapat makita sa katulad ng datos sa 40 A$\cdot$GeV. Ang pag-aaral sa Jet-Wake-riding potentials at Bow shocks—na dulot ng mga jet sa QGP na nabuo sa RHIC—ay maaaring magbigay ng karagdagang impormasyon tungkol sa equation of state (EoS) at transport coefficients ng Quark Gluon Plasma (QGP).
|
tl
|
Respondent-driven sampling is a survey method for hidden or hard-to-reach populations in which sampled individuals recruit others in the study population via their social links. The most popular estimator for for the population mean assumes that individual sampling probabilities are proportional to each subject's reported degree in a social network connecting members of the hidden population. However, it remains unclear under what circumstances these estimators are valid, and what assumptions are formally required to identify population quantities. In this short note we detail nonparametric identification results for the population mean when the sampling probability is assumed to be a function of network degree known to scale. Importantly, we establish general conditions for the consistency of the popular Volz-Heckathorn (VH) estimator. Our results imply that the conditions for consistency of the VH estimator are far less stringent than those suggested by recent work on diagnostics for RDS. In particular, our results do not require random sampling or the existence of a network connecting the population.
|
El muestreo basado en respondientes es un método de encuesta para poblaciones ocultas o de difícil acceso en el que los individuos muestreados reclutan a otros miembros de la población de estudio a través de sus vínculos sociales. El estimador más popular para la media poblacional asume que las probabilidades individuales de muestreo son proporcionales al grado reportado por cada sujeto en una red social que conecta a los miembros de la población oculta. Sin embargo, aún no está claro bajo qué circunstancias estos estimadores son válidos, ni qué supuestos se requieren formalmente para identificar cantidades poblacionales. En esta breve nota detallamos resultados de identificación no paramétrica para la media poblacional cuando se asume que la probabilidad de muestreo es una función del grado en la red cuya escala es conocida. Es importante destacar que establecemos condiciones generales para la consistencia del popular estimador de Volz-Heckathorn (VH). Nuestros resultados implican que las condiciones para la consistencia del estimador VH son mucho menos exigentes que las sugeridas por trabajos recientes sobre diagnósticos para RDS. En particular, nuestros resultados no requieren muestreo aleatorio ni la existencia de una red que conecte a la población.
|
es
|
Let A be a C*-algebra and A** its enveloping von Neumann algebra. C. Akemann suggested a kind of non-commutative topology in which certain projections in A** play the role of open sets. The adjectives "open", "closed", "compact", and "relatively compact" all can be applied to projections in A**. Two operator inequalities were used by Akemann in connection with compactness. Both of these inequalities are equivalent to compactness for a closed projection in A**, but only one is equivalent to relative compactness for a general projection. A third operator inequality, also related to compactness, was used by the author. It turns out that the study of all three inequalities can be unified by considering a numerical invariant which is equivalent to the distance of a projection from the set of relatively compact projections. Since the subject concerns the relation between a projection and its closure, Tomita's concept of regularity of projections seems relevant, and some results and examples on regularity are also given. A few related results on semicontinuity are also included.
|
Sia A una C*-algebra e A** la sua algebra di von Neumann inviluppante. C. Akemann ha suggerito una sorta di topologia non commutativa in cui certe proiezioni in A** svolgono il ruolo di insiemi aperti. Gli aggettivi "aperto", "chiuso", "compatto" e "relativamente compatto" possono tutti essere applicati a proiezioni in A**. Akemann ha utilizzato due disuguaglianze operatoriali in relazione alla compattezza. Entrambe queste disuguaglianze sono equivalenti alla compattezza per una proiezione chiusa in A**, ma solo una è equivalente alla compattezza relativa per una proiezione generica. Un terzo disuguaglianza operatoriale, anch'essa legata alla compattezza, è stata utilizzata dall'autore. Risulta che lo studio delle tre disuguaglianze può essere unificato considerando un invariante numerico equivalente alla distanza di una proiezione dall'insieme delle proiezioni relativamente compatte. Poiché l'argomento riguarda la relazione tra una proiezione e la sua chiusura, il concetto di Tomita sulla regolarità delle proiezioni appare pertinente, e vengono forniti alcuni risultati ed esempi sulla regolarità. Sono inclusi anche alcuni risultati collegati sulla semicontinuità.
|
it
|
The first measured results for massive multiple-input, multiple-output (MIMO) performance in a line-of-sight (LOS) scenario with moderate mobility are presented, with 8 users served by a 100 antenna base Station (BS) at 3.7 GHz. When such a large number of channels dynamically change, the inherent propagation and processing delay has a critical relationship with the rate of change, as the use of outdated channel information can result in severe detection and precoding inaccuracies. For the downlink (DL) in particular, a time division duplex (TDD) configuration synonymous with massive MIMO deployments could mean only the uplink (UL) is usable in extreme cases. Therefore, it is of great interest to investigate the impact of mobility on massive MIMO performance and consider ways to combat the potential limitations. In a mobile scenario with moving cars and pedestrians, the correlation of the MIMO channel vector over time is inspected for vehicles moving up to 29 km/h. For a 100 antenna system, it is found that the channel state information (CSI) update rate requirement may increase by 7 times when compared to an 8 antenna system, whilst the power control update rate could be decreased by at least 5 times relative to a single antenna system.
|
Jsou prezentovány první naměřené výsledky výkonu masivního systému s více vstupy a více výstupy (MIMO) ve scénáři s přímou viditelností (LOS) a střední pohyblivostí, při kterém 8 uživatelů je obsluhováno základnovou stanicí (BS) s 100 anténami na frekvenci 3,7 GHz. Když takový velký počet kanálů dynamicky mění, má vlastní šíření a zpracovací zpoždění kritický vztah k rychlosti změny, protože použití zastaralých informací o kanálu může vést k výrazným nepřesnostem detekce a předkódování. Zejména pro sestupný směr (DL) může konfigurace s dělením času (TDD), která je typická pro nasazení masivních MIMO systémů, znamenat, že ve výjimečných případech je použitelný pouze směr výstupní (UL). Je tedy velmi důležité prozkoumat vliv pohyblivosti na výkon masivních MIMO systémů a zvážit možnosti, jak překonat potenciální omezení. Ve scénáři s pohybem vozidel a chodců je zkoumána časová korelace vektoru MIMO kanálu pro vozidla pohybující se rychlostí až 29 km/h. U systému s 100 anténami bylo zjištěno, že požadovaná frekvence aktualizace informací o stavu kanálu (CSI) může být až 7krát vyšší ve srovnání se systémem s 8 anténami, zatímco frekvence aktualizace řízení výkonu by mohla být snížena alespoň 5krát ve srovnání se systémem s jednou anténou.
|
cs
|
A critical component in the implementation of a concurrent tabling system is the design of the table space. One of the most successful proposals for representing tables is based on a two-level trie data structure, where one trie level stores the tabled subgoal calls and the other stores the computed answers. In this work, we present a simple and efficient lock-free design where both levels of the tries can be shared among threads in a concurrent environment. To implement lock-freedom we took advantage of the CAS atomic instruction that nowadays can be widely found on many common architectures. CAS reduces the granularity of the synchronization when threads access concurrent areas, but still suffers from low-level problems such as false sharing or cache memory side-effects. In order to be as effective as possible in the concurrent search and insert operations over the table space data structures, we based our design on a hash trie data structure in such a way that it minimizes potential low-level synchronization problems by dispersing as much as possible the concurrent areas. Experimental results in the Yap Prolog system show that our new lock-free hash trie design can effectively reduce the execution time and scale better than previous designs.
|
مترافع جدول کے نظام کے نفاذ میں میز کی جگہ کا ڈیزائن ایک اہم جزو ہے۔ جدوں کی نمائندگی کرنے کے لیے سب سے کامیاب ترین تجاویز میں سے ایک دو سطحی ٹرائی ڈیٹا ڈھانچے پر مبنی ہے، جہاں ایک ٹرائی سطح میز پر مبنی ذیلی مقصد کالز کو ذخیرہ کرتی ہے اور دوسری حساب کی گئی جوابات کو ذخیرہ کرتی ہے۔ اس کام میں، ہم ایک سادہ اور موثر لاک فری ڈیزائن پیش کرتے ہیں جہاں دونوں سطحیں ٹرائی کی ایک مترافع ماحول میں دھاگوں کے درمیان مشترکہ ہو سکتی ہیں۔ لاک فری نفاذ کے لیے، ہم نے اس وقت عام طور پر بہت سی عام آرکیٹیکچرز پر پائی جانے والی CAS ایٹامک ہدایت کا فائدہ اٹھایا۔ CAS مترافع علاقوں تک دھاگوں کی رسائی کے دوران ہم وقت سازی کی دقیق تفصیل کو کم کرتا ہے، لیکن اب بھی غلط شیئرنگ یا کیش میموری کے جانبی اثرات جیسے کم سطحی مسائل سے گرا ہوا ہے۔ میز کی جگہ ڈیٹا ڈھانچوں پر مترافع تلاش اور داخل کرنے کے آپریشنز میں جتنا ممکن ہو اتنا مؤثر ہونے کے لیے، ہم نے اپنے ڈیزائن کو ہیش ٹرائی ڈیٹا ڈھانچے پر مبنی بنایا اس طرح کہ یہ ممکنہ کم سطحی ہم وقت سازی کے مسائل کو اس حد تک کم کرتا ہے کہ مترافع علاقوں کو زیادہ سے زیادہ بکھیر دیا جائے۔ یاپ پرولوگ سسٹم میں تجرباتی نتائج ظاہر کرتے ہیں کہ ہمارا نیا لاک فری ہیش ٹرائی ڈیزائن مؤثر طریقے سے انجام دینے کے وقت کو کم کر سکتا ہے اور پچھلے ڈیزائنز کے مقابلے میں بہتر اسکیل کر سکتا ہے۔
|
ur
|
We derive mass functions (MF) for halo red dwarfs (the faintest hydrogen burning stars) and then extrapolate to place limits on the total mass of halo brown dwarfs (stars not quite massive enough to burn hydrogen). The mass functions are obtained from the luminosity function of a sample of 114 local halo stars in the USNO parallax survey (Dahn \etal 1995). We use stellar models of Alexander \etal (1996) and make varying assumptions about metallicity and about possible unresolved binaries in the sample. We find that the MF for halo red dwarfs cannot rise more quickly than $1/m^2$ as one approaches the hydrogen burning limit. Using recent results from star formation theory, we extrapolate the MF into the brown-dwarf regime. We see that likely extrapolations imply that the total mass of brown dwarfs in the halo is less than $\sim 3\%$ of the local mass density of the halo ($\sim 0.3\%$ for the more realistic models we consider). Our limits apply to brown dwarfs in the halo that come from the same stellar population as the red dwarfs.
|
نشتق دوال الكتلة (MF) لأقزام الهالة الحمراء (نجوم احتراق الهيدروجين الأضعف سطوعًا)، ثم نقوم بالاستكمال للحصول على حدود للكتلة الكلية لأقزام الهالة البنية (نجوم ليست ضخمة بما يكفي لاحتراق الهيدروجين). تم الحصول على دوال الكتلة من دالة اللمعان لعينة مكوّنة من 114 نجمًا محليًا من نجوم الهالة في مسح شذوذ الموقع التابع للمكتب البحري الأمريكي (Dahn وآخرون 1995). نستخدم نماذج نجمية من Alexander وآخرون (1996)، ونضع افتراضات متفاوتة حول المعادن ووجود ثنائيات غير محلولة في العينة. نجد أن دالة الكتلة لأقزام الهالة الحمراء لا يمكن أن تزداد أسرع من $1/m^2$ كلما اقتربنا من حد احتراق الهيدروجين. باستخدام نتائج حديثة من نظرية تشكل النجوم، نُجرِي استكمالاً لدالة الكتلة إلى نطاق الأقزام البنية. نلاحظ أن الاستكمالات المحتملة تشير إلى أن الكتلة الكلية للأقزام البنية في الهالة أقل من $\sim 3\%$ من كثافة الكتلة المحلية للهالة ($\sim 0.3\%$ بالنسبة للنماذج الأكثر واقعية التي ننظر فيها). تنطبق حدودنا على الأقزام البنية في الهالة التي تأتي من نفس الكتلة النجمية التي تأتي منها الأقزام الحمراء.
|
ar
|
Large amounts of labeled training data are one of the main contributors to the great success that deep models have achieved in the past. Label acquisition for tasks other than benchmarks can pose a challenge due to requirements of both funding and expertise. By selecting unlabeled examples that are promising in terms of model improvement and only asking for respective labels, active learning can increase the efficiency of the labeling process in terms of time and cost. In this work, we describe combinations of an incremental learning scheme and methods of active learning. These allow for continuous exploration of newly observed unlabeled data. We describe selection criteria based on model uncertainty as well as expected model output change (EMOC). An object detection task is evaluated in a continuous exploration context on the PASCAL VOC dataset. We also validate a weakly supervised system based on active and incremental learning in a real-world biodiversity application where images from camera traps are analyzed. Labeling only 32 images by accepting or rejecting proposals generated by our method yields an increase in accuracy from 25.4% to 42.6%.
|
Jumlah besar data latihan berlabel merupakan salah satu penyumbang utama kepada kejayaan besar yang dicapai oleh model-model dalam kedalaman pada masa lalu. Perolehan label untuk tugas-tugas selain daripada tolok ukur boleh menimbulkan cabaran disebabkan oleh keperluan kewangan dan kepakaran. Dengan memilih contoh tanpa label yang menjanjikan dari segi penambahbaikan model dan hanya meminta label yang berkaitan, pembelajaran aktif boleh meningkatkan kecekapan proses pelabelan dari segi masa dan kos. Dalam karya ini, kami menerangkan gabungan skema pembelajaran inkremental dan kaedah pembelajaran aktif. Gabungan ini membolehkan penerokaan berterusan terhadap data tanpa label yang baharu diperhatikan. Kami menerangkan kriteria pemilihan berdasarkan ketidakyakinan model serta perubahan keluaran model dijangka (EMOC). Tugas pengesanan objek dinilai dalam konteks penerokaan berterusan menggunakan set data PASCAL VOC. Kami juga mengesahkan sistem penyeliaan lemah berdasarkan pembelajaran aktif dan inkremental dalam aplikasi kepelbagaian biologi dunia sebenar di mana imej dari perangkap kamera dianalisis. Dengan melabelkan hanya 32 imej melalui penerimaan atau penolakan cadangan yang dijana oleh kaedah kami, ketepatan meningkat daripada 25.4% kepada 42.6%.
|
ms
|
We study surface operators in 3d Topological Field Theory and their relations with 2d Rational Conformal Field Theory. We show that a surface operator gives rise to a consistent gluing of chiral and anti-chiral sectors in the 2d RCFT. The algebraic properties of the resulting 2d RCFT, such as the classification of symmetry-preserving boundary conditions, are expressed in terms of properties of the surface operator. We show that to every surface operator one may attach a Morita-equivalence class of symmetric Frobenius algebras in the ribbon category of bulk line operators. This provides a simple interpretation of the results of Fuchs, Runkel and Schweigert on the construction of 2d RCFTs from Frobenius algebras. We also show that every topological boundary condition in a 3d TFT gives rise to a commutative Frobenius algebra in the category of bulk line operators. We illustrate these general considerations by studying in detail surface operators in abelian Chern-Simons theory.
|
ကျွန်ုပ်တို့သည် ၃D ထိပ်တန်းအဆင့် ကွင်းအလှည့်အပြောင်း သီအိုရီ (Topological Field Theory) တွင် မျက်နှာပြင် အော်ပရေတာများနှင့် ၎င်းတို့၏ ၂D အက်စ်အိုရှင်နယ် ကွန်ဖောင်မယ် ကွင်းအလှည့်အပြောင်း သီအိုရီ (Rational Conformal Field Theory) နှင့် ဆက်စပ်မှုများကို လေ့လာပါသည်။ မျက်နှာပြင် အော်ပရေတာတစ်ခုသည် ၂D RCFT တွင် ချိုင်ရယ်နှင့် အန်တီ-ချိုင်ရယ် ဌာနများကို ကိုက်ညီစွာ ဆက်စပ်ပေးကြောင်း ပြသပါသည်။ ၂D RCFT ၏ အယ်လဂျီဘရာ ဂုဏ်သတ္တိများဖြစ်သော စင်မျှခြေ ထိန်းသိမ်းပေးသည့် နယ်နိမိတ် အခြေအနေများကို အမျိုးအစားခွဲခြားခြင်း စသည်တို့ကို မျက်နှာပြင် အော်ပရေတာ၏ ဂုဏ်သတ္တိများဖြင့် ဖော်ပြနိုင်ပါသည်။ မျက်နှာပြင် အော်ပရေတာတစ်ခုစီအတွက် မျက်နှာပြင် လိုင်း အော်ပရေတာများ၏ ရိုက်ဘွန် ကဏ္ဍ (ribbon category) တွင် စီမီထရစ် ဖရိုဘီနီးယပ်စ် အယ်လဂျီဘရာများ၏ မိုရီတာ-ညီမျှမှု အတန်း (Morita-equivalence class) တစ်ခုကို ဆက်စပ်နိုင်ကြောင်း ပြသပါသည်။ ဤအရာမှာ Frobenius အယ်လဂျီဘရာများမှ ၂D RCFT များကို တည်ဆောက်ခြင်းနှင့်ပတ်သက်၍ Fuchs, Runkel နှင့် Schweigert တို့၏ ရလဒ်များကို ရိုးရှင်းစွာ အဓိပ္ပါယ်ကောက်ယူနိုင်မှုကို ပေးစွမ်းပါသည်။ ထို့အပြင် ၃D TFT တွင် ထိပ်တန်းအဆင့် နယ်နိမိတ် အခြေအနေတိုင်းသည် မျက်နှာပြင် လိုင်း အော်ပရေတာများ၏ ကဏ္ဍတွင် ဖလှယ်နိုင်သော Frobenius အယ်လဂျီဘရာတစ်ခုကို ဖန်တီးပေးကြောင်းလည်း ပြသပါသည်။ ကျွန်ုပ်တို့သည် အေဘီလီယန် ချန်-ဆီမွန်း သီအိုရီ (abelian Chern-Simons theory) တွင် မျက်နှာပြင် အော်ပရေတာများကို အသေးစိတ် လေ့လာခြင်းဖြင့် ဤအထက်ပါ ယေဘုယျ သုံးသပ်ချက်များကို ရှင်းလင်းပြသပါသည်။
|
my
|
Historically the training of teams has been implemented using a face-to-face approach. In the past decade, on-line multiuser virtual environments have offered a solution for training teams whose members are geographically dispersed. In order to develop on effective team training activity, a high sense of presence among the participant needs to be reached. Previous research studies reported being able to reach a high level of presence even when using inexpensive technology such as laptop and headset. This study evaluates the level of presence of ten subjects who have to perform a team-building activity in a multi-user virtual environment using a laptop computer and a headset. The authors are interested in determining which user characterizes, such as gender, age and knowledge of computers, have a strong correlation with the level of sense of presence. The results of this study showed that female participants were more likely to engage in the activity and perceived fewer negative effects. Participants who reported less negative effects such as feeling tired, dizzy, or experiencing eye strain during the team-building activity reached a higher level of sense of presence.
|
Historicamente, o treinamento de equipes tem sido implementado por meio de uma abordagem presencial. Na última década, ambientes virtuais multiusuário on-line ofereceram uma solução para o treinamento de equipes cujos membros estão geograficamente dispersos. Para desenvolver uma atividade eficaz de treinamento em equipe, é necessário alcançar um alto nível de sensação de presença entre os participantes. Estudos anteriores relataram ser possível alcançar um alto nível de presença mesmo ao utilizar tecnologia de baixo custo, como laptop e fone de ouvido. Este estudo avalia o nível de presença de dez sujeitos que precisam realizar uma atividade de formação de equipes em um ambiente virtual multiusuário utilizando um computador portátil e um fone de ouvido. Os autores têm interesse em determinar quais características dos usuários, como sexo, idade e conhecimento em informática, possuem forte correlação com o nível de sensação de presença. Os resultados deste estudo mostraram que as participantes do sexo feminino tinham maior probabilidade de se envolver na atividade e perceberam menos efeitos negativos. Os participantes que relataram menos efeitos negativos, como sentir-se cansado, tonto ou ter problemas de visão durante a atividade de formação de equipes, alcançaram um nível mais alto de sensação de presença.
|
pt
|
The ground field in the text is of characteristic 2. The classification of modulo 2 gradings of simple Lie algebras is vital for the classification of simple finite-dimensional Lie superalgebras: with each grading, a simple Lie superalgebra is associated, see arXiv:1407.1695. No classification of gradings was known for any type of simple Lie algebras, bar restricted Jacobson-Witt algebras (i.e., the first derived of the Lie algebras of vector fields with truncated polynomials as coefficients) on not less than 3 indeterminates. Here we completely describe gradings modulo 2 for several series of Lie algebras and their simple relatives: of special linear series, its projectivizations, and projectivizations of the derived Lie algebras of two inequivalent orthogonal series (except for ${\mathfrak{o}}_\Pi(8)$). The classification of gradings is new, but all of the corresponding superizations are known. For the simple derived Zassenhaus algebras of height $n>1$, there is an $(n-2)$-parametric family of modulo 2 gradings; all but one of the corresponding simple Lie superalgebras are new. Our classification also proves non-triviality of a deformation of a simple $3|2$-dimensional Lie superalgebra (new result).
|
စာသားတွင် မြေပြင်ကွင်းသည် ဂုဏ်သတ္တိ ၂ ရှိသည်။ ရိုးရှင်းသော လီအယ်(ဘ်)ဂျီဘရာများ၏ မော်ဒျူလို ၂ အဆင့်သတ်မှတ်မှုများကို အမျိုးအစားခွဲခြားခြင်းသည် ရိုးရှင်းသော ကန့်သတ်အရွယ်အစားရှိ လီစူပါအယ်(ဘ်)ဂျီဘရာများကို အမျိုးအစားခွဲရန် အရေးပါသည်။ အဆင့်သတ်မှတ်မှုတစ်ခုစီနှင့် တွဲဖက်၍ ရိုးရှင်းသော လီစူပါအယ်(ဘ်)ဂျီဘရာတစ်ခုရှိပြီး arXiv:1407.1695 ကို ကြည့်ပါ။ ရိုးရှင်းသော လီအယ်(ဘ်)ဂျီဘရာများ၏ အမျိုးအစားမည်သည့်မျိုးအတွက်မျှ အဆင့်သတ်မှတ်မှုအမျိုးအစားခွဲခြားမှုကို မသိရသေးပါ။ သို့သော် ကန့်သတ်ထားသော ဂျိုက်ဘ်ဆန်-ဝစ်အယ်(ဘ်)ဂျီဘရာများ (ဆိုလိုသည်မှာ ကိန်းရှင်များကို မျှင်ထားသော စက်ဝိုင်းများဖြင့် ရှိသော ဗက်တာကွင်းများ၏ လီအယ်(ဘ်)ဂျီဘရာများ၏ ပထမဆင့်ဆင့်ဖြစ်သော အယ်(ဘ်)ဂျီဘရာများ) အတွက် အနည်းဆုံး ကိန်းရှင် ၃ ခုနှင့်အထက်တွင် အဆင့်သတ်မှတ်မှုများကို အမျိုးအစားခွဲခြားထားသည်။ ဤနေရာတွင် လီအယ်(ဘ်)ဂျီဘရာများ၏ အဆင့်များနှင့် ၎င်းတို့၏ ရိုးရှင်းသော ဆက်စပ်အယ်(ဘ်)ဂျီဘရာများဖြစ်သော အထူးလိုင်းနီယာအဆင့်များ၊ ၎င်းတို့၏ ပရောဂျက်တစ်ဖြစ်များနှင့် မညီမျှသော အော်သိုဂိုနယ်အဆင့်နှစ်ခု၏ ဆင့်ကဲဖြစ်လီအယ်(ဘ်)ဂျီဘရာများ၏ ပရောဂျက်တစ်ဖြစ်များ ( ${\mathfrak{o}}_\Pi(8)$ ကို除ကွဲ၍) တို့အတွက် မော်ဒျူလို ၂ အဆင့်များကို အပြည့်အဝဖော်ပြထားသည်။ အဆင့်သတ်မှတ်မှုများကို အမျိုးအစားခွဲခြင်းသည် အသစ်ဖြစ်သော်လည်း အကူးအပြောင်းလုပ်ထားသော လီစူပါအယ်(ဘ်)ဂျီဘရာများအားလုံးကို သိပြီးသားဖြစ်သည်။ အမြင့် $n>1$ ရှိသော ရိုးရှင်းသော ဆင့်ကဲဖြစ် ဇက်ဆင်ဟောက်အယ်(ဘ်)ဂျီဘရာများအတွက် မော်ဒျူလို ၂ အဆင့်သတ်မှတ်မှုများ၏ $(n-2)$-ပါရာမီတာ မိသားစုရှိပြီး အကူးအပြောင်းလုပ်ထားသော ရိုးရှင်းသော လီစူပါအယ်(ဘ်)ဂျီဘရာများအနက် တစ်ခုကို除ကွဲ၍ အားလုံးသည် အသစ်ဖြစ်သည်။ ကျွန်ုပ်တို့၏ အမျိုးအစားခွဲခြားမှုသည် ရိုးရှင်းသော $3|2$-အရွယ်အစားရှိ လီစူပါအယ်(ဘ်)ဂျီဘရာ၏ ပုံပျက်မှုတစ်ခု၏ မကွေးမှုကို သက်သေပြသည် (အသစ်သောရလဒ်)။
|
my
|
We have conducted a $UBVRI$ and $H_{\alpha}$ CCD photometry of 5 barred galaxies, NGC 2523, NGC 2950, NGC 3412, NGC 3945 and NGC 5383, along with SPH simulations, in order to understand the origin of young stellar populations in the nuclei of barred galaxies. The $H_{\alpha}$ emissions which are thought to be emitted by young stellar populations are either absent or strongly concentrated on the nuclei of early type galaxies (NGC 2950, NGC 3412, NGC 3945), while they are observed in the nuclei and circumnuclear regions of intermediate type galaxies with strong bars (NGC 2523, NGC 5383). SPH simulations of realistic mass models for these galaxies show that some disk material can be driven into the nuclear regions by strong bar potentials. This implies that the young stellar populations in the circumnuclear regions of barred galaxies can be formed out of such gas. The existence of the nuclear dust lanes is an indication of an on-going gas inflow and extremely young stellar populations in these galaxies, because the nuclear dust lanes such as those in NGC 5383 are not long-lasting features according to our simulations.
|
ကြယ်သစ်များ ပေါ်ပေါက်လာပုံကို နားလည်ရန် ဘားပါသော ဂယ်လက်ဆီ ၅ ခုဖြစ်သည့် NGC 2523၊ NGC 2950၊ NGC 3412၊ NGC 3945 နှင့် NGC 5383 တို့ကို $UBVRI$ နှင့် $H_{\alpha}$ CCD အလင်းချိန်ခြင်းများ ပြုလုပ်ခဲ့ပြီး SPH စမ်းသပ်မှုများကိုပါ ပြုလုပ်ခဲ့သည်။ ကြယ်ငယ်များမှ ထုတ်လွှတ်သည်ဟု ယူဆရသော $H_{\alpha}$ ထုတ်လွှတ်မှုများမှာ အစောပိုင်းအမျိုးအစား ဂယ်လက်ဆီများ (NGC 2950၊ NGC 3412၊ NGC 3945) ၏ ဗဟိုတွင် မရှိခြင်း (သို့) အလွန်စုစည်းနေခြင်းဖြစ်ပြီး အလယ်အလတ်အမျိုးအစား ကြီးမားသော ဘားပါသည့် ဂယ်လက်ဆီများ (NGC 2523၊ NGC 5383) ၏ ဗဟိုနှင့် ဗဟိုပတ်လည်ဒေသများတွင် တွေ့ရသည်။ ဤဂယ်လက်ဆီများအတွက် အမှန်တကယ်ရှိသည့် မဟုတ်သော စမ်းသပ်မှုများမှ ပြသသည်မှာ ကြီးမားသော ဘား၏ ပြင်းထန်သည့် စွမ်းအင်ဖြင့် ဒစ်ခ်ပေါ်ရှိ ပစ္စည်းအချို့သည် ဗဟိုဒေသများသို့ ရွေ့လျားနိုင်ကြောင်းဖြစ်သည်။ ဤအချက်မှာ ဘားပါသည့် ဂယ်လက်ဆီများ၏ ဗဟိုပတ်လည်ဒေသများတွင် ကြယ်သစ်များ ဖြစ်ပေါ်လာခြင်းသည် ဤကဲ့သို့သော ဓာတ်ငွေ့များမှ ဖြစ်ပေါ်လာနိုင်ကြောင်း ညွှန်ပြနေသည်။ ဗဟိုတွင် ဖုန်မှုန့်လမ်းကြောင်းများရှိခြင်းမှာ ဤဂယ်လက်ဆီများတွင် ဓာတ်ငွေ့များ စီးဝင်နေခြင်းနှင့် အလွန်ငယ်ရွယ်သော ကြယ်များရှိနေခြင်းကို ညွှန်ပြနေသည်။ အကြောင်းမှာ NGC 5383 တွင်ရှိသည့် ဗဟိုဖုန်မှုန့်လမ်းကြောင်းများကဲ့သို့ ဗဟိုဖုန်မှုန့်လမ်းကြောင်းများသည် ကျွန်ုပ်တို့၏ စမ်းသပ်မှုများအရ ကြာရှည်စွာ မတည်ရှိနိုင်သော အရာများဖြစ်သောကြောင့်ဖြစ်သည်။
|
my
|
This paper describes how born digital primary sources could be used to reconstruct the recent history of scientific institutions. The case study is an analysis of the first 25 years online of the University of Bologna. The focus of this work is primarily methodological: several different issues are presented, starting with the fact that the University of Bologna website has been excluded for thirteen years from the Internet Archive's Wayback Machine, and possible solutions are proposed and applied. The article is organised in three parts: in the first one, some of the fundamental concepts on web archives and the preservation of born digital sources are introduced. Then the reconstruction of the University of Bologna web's past is presented. Finally the future of this research is described, presenting a specific case study in which the historian's craft will be challenged by a completely different issue, namely the large amount of data available in the university digital library.
|
ບົດຄວາມນີ້ອະທິບາຍກ່ຽວກັບວິທີການທີ່ແຫຼ່ງຂໍ້ມູນດິບທີ່ເກີດຈາກດິຈິຕອນສາມາດນຳໃຊ້ເພື່ອສ້າງປະຫວັດສາດໃໝ່ຂອງສະຖາບັນດ້ານວິທະຍາສາດຂຶ້ນໃໝ່. ກໍລະນີສຶກສາແມ່ນການວິເຄາະ 25 ປີທຳອິດທີ່ມີການເຂົ້າເຖິງອິນເຕີເນັດຂອງມະຫາວິທະຍາໄລບໍໂລຍ່າ. ຈຸດສຸມຂອງວຽກງານນີ້ແມ່ນຢູ່ໃນດ້ານວິທີການເປັນສ່ວນໃຫຍ່: ມີການນຳເອົາບັນຫາຫຼາຍດ້ານມານຳສະເໜີ, ເລີ່ມຈາກຄວາມຈິງທີ່ວ່າເວັບໄຊທ໌ຂອງມະຫາວິທະຍາໄລບໍໂລຍ່າຖືກຍົກເວັ້ນອອກຈາກ Wayback Machine ຂອງສະຖາບັນ Internet Archive ເປັນໄລຍະເວລາ 13 ປີ, ແລະ ມີການສະເໜີແລະນຳໃຊ້ວິທີແກ້ໄຂທີ່ເປັນໄປໄດ້. ບົດຄວາມແບ່ງອອກເປັນສາມສ່ວນ: ໃນສ່ວນທຳອິດ, ມີການນຳສະເໜີບາງຄຳນິຍົມພື້ນຖານກ່ຽວກັບເວັບໄຊທ໌ເກັບຮັກສາຂໍ້ມູນ ແລະ ການຮັກສາແຫຼ່ງຂໍ້ມູນດິບທີ່ເກີດຈາກດິຈິຕອນ. ຕໍ່ມາກໍນຳສະເໜີການສ້າງປະຫວັດເວັບໄຊທ໌ຂອງມະຫາວິທະຍາໄລບໍໂລຍ່າຂຶ້ນໃໝ່. ສຸດທ້າຍມີການອະທິບາຍກ່ຽວກັບອະນາຄົດຂອງການຄົ້ນຄວ້ານີ້, ໂດຍການນຳສະເໜີກໍລະນີສຶກສາທີ່ຊັດເຈນ ເຊິ່ງວຽກງານຂອງນັກປະຫວັດສາດຈະຖືກທ້າທາຍດ້ວຍບັນຫາທີ່ແຕກຕ່າງຢ່າງສິ້ນເຊີງ, ນັ້ນກໍຄືປະລິມານຂໍ້ມູນທີ່ມີຢູ່ເປັນຈຳນວນຫຼວງຫຼາຍໃນຫໍສະໝຸດດິຈິຕອນຂອງມະຫາວິທະຍາໄລ.
|
lo
|
In this paper, we provide non-parametric statistical tools to test stationarity of microstructure noise in general hidden Ito semimartingales, and discuss how to measure liquidity risk using high frequency financial data. In particular, we investigate the impact of non-stationary microstructure noise on some volatility estimators, and design three complementary tests by exploiting edge effects, information aggregation of local estimates and high-frequency asymptotic approximation. The asymptotic distributions of these tests are available under both stationary and non-stationary assumptions, thereby enable us to conservatively control type-I errors and meanwhile ensure the proposed tests enjoy the asymptotically optimal statistical power. Besides it also enables us to empirically measure aggregate liquidity risks by these test statistics. As byproducts, functional dependence and endogenous microstructure noise are briefly discussed. Simulation with a realistic configuration corroborates our theoretical results, and our empirical study indicates the prevalence of non-stationary microstructure noise in New York Stock Exchange.
|
본 논문에서 우리는 일반적인 잠재적 이토 반마팅게일에서 마이크로스트럭처 노이즈의 정상성을 검정하기 위한 비모수적 통계 도구를 제공하고, 고빈도 금융 데이터를 이용하여 유동성 리스크를 측정하는 방법을 논의한다. 특히, 비정상 마이크로스트럭처 노이즈가 일부 변동성 추정량에 미치는 영향을 조사하고, 가장자리 효과, 국소 추정치의 정보 집계, 고빈도 점근 근사화를 활용하여 세 가지 상호보완적인 검정법을 설계한다. 이러한 검정 통계량의 점근 분포는 정상성과 비정상성 가정 하에서 모두 도출 가능하므로, 제1종 오류를 보수적으로 통제하면서 동시에 제안된 검정법들이 점근적으로 최적의 통계적 검정력을 갖도록 할 수 있다. 또한 이러한 검정 통계량을 통해 실증적으로 집계 유동성 리스크를 측정할 수 있다. 부산물로서 함수적 종속성과 내생적 마이크로스트럭처 노이즈에 대해서도 간략히 논의한다. 현실적인 설정 하의 시뮬레이션은 우리의 이론적 결과를 뒷받침하며, 실증 분석을 통해 뉴욕증권거래소에서 비정상 마이크로스트럭처 노이즈가 널리 존재함을 확인하였다.
|
ko
|
The oriented link of the cyclic quotient singularity $\mathcal{X}_{p,q}$ is orientation-preserving diffeomorphic to the lens space $L(p,q)$ and carries the standard contact structure $\xi_{st}$. Lisca classified the Stein fillings of $(L(p,q), \xi_{st})$ up to diffeomorphisms and conjectured that they correspond bijectively through an {\it explicit} map to the Milnor fibers associated with the irreducible components (all of them being smoothing components) of the reduced miniversal space of deformations of $\mathcal{X}_{p,q}$. We prove this conjecture using the smoothing equations given by Christophersen and Stevens. Moreover, based on a different description of the Milnor fibers given by de Jong and van Straten, we also canonically identify these fibers with Lisca's fillings. Using these and a newly introduced additional structure - the order - associated with lens spaces, we prove that the above Milnor fibers are pairwise non-diffeomorphic (by diffeomorphisms which preserve the orientation and order). This also implies that de Jong and van Straten parametrize in the same way the components of the reduced miniversal space of deformations as Christophersen and Stevens.
|
ສຳລັບຈຸດຕັດຂອງສິ່ງຜິດປົກກະຕິແບບວົງກົມ $\mathcal{X}_{p,q}$ ນັ້ນ ມີການເຊື່ອມຕໍ່ທິດທາງທີ່ສອດຄ່ອງກັບພື້ນທີ່ເລນ $L(p,q)$ ແລະ ມີໂຄງສ້າງການຕິດຕໍ່ມາດຕະຖານ $\xi_{st}$ ຢູ່ໃນນັ້ນ. Lisca ໄດ້ຈັດປະເພດການຕື່ມ Stein ຂອງ $(L(p,q), \xi_{st})$ ຕາມການແປງຮູບທີ່ສອດຄ່ອງກັນ ແລະ ສົມມຸດວ່າ ພວກມັນຈະສອດຄ່ອງກັນແບບໜຶ່ງຕໍ່ໜຶ່ງ ຜ່ານແຜນທີ່ທີ່ {\it ຊັດເຈນ} ກັບເສັ້ນໃຍ Milnor ທີ່ກ່ຽວຂ້ອງກັບສ່ວນປະກອບທີ່ບໍ່ສາມາດແຍກອອກໄດ້ (ທັງໝົດນີ້ແມ່ນສ່ວນປະກອບທີ່ເຮັດໃຫ້ກາຍເປັນກົມກຽວ) ຂອງພື້ນທີ່ການເຄື່ອນຍ້າຍທີ່ນ້ອຍທີ່ສຸດແບບຫຼຸດລົງຂອງ $\mathcal{X}_{p,q}$. ພວກເຮົາພິສູດສົມມຸດນີ້ໂດຍໃຊ້ສົມຜົນການກ້ຽງທີ່ຖືກໃຫ້ໂດຍ Christophersen ແລະ Stevens. ນອກຈາກນັ້ນ, ໂດຍອີງໃສ່ການອະທິບາຍອີກຮູບແບບໜຶ່ງຂອງເສັ້ນໃຍ Milnor ທີ່ຖືກໃຫ້ໂດຍ de Jong ແລະ van Straten, ພວກເຮົາຍັງສາມາດກຳນົດຕົວຕົນເອງຂອງເສັ້ນໃຍເຫຼົ່ານີ້ກັບການຕື່ມຂອງ Lisca ໄດ້ຢ່າງຖືກຕ້ອງ. ໂດຍໃຊ້ຂໍ້ມູນເຫຼົ່ານີ້ ແລະ ໂຄງສ້າງເພີ່ມເຕີມໃໝ່ - ລຳດັບ - ທີ່ກ່ຽວຂ້ອງກັບພື້ນທີ່ເລນ, ພວກເຮົາພິສູດວ່າ ເສັ້ນໃຍ Milnor ຂ້າງເທິງນີ້ບໍ່ມີຄວາມເທົ່າກັນໃນການແປງຮູບ (ໂດຍການແປງຮູບທີ່ຮັກສາທິດທາງ ແລະ ລຳດັບໄວ້). ສິ່ງນີ້ຍັງໝາຍຄວາມວ່າ de Jong ແລະ van Straten ໄດ້ກຳນົດພາລາມິເຕີໃຫ້ກັບສ່ວນປະກອບຂອງພື້ນທີ່ການເຄື່ອນຍ້າຍທີ່ນ້ອຍທີ່ສຸດແບບຫຼຸດລົງໃນທາງດຽວກັນກັບທີ່ Christophersen ແລະ Stevens ໄດ້ກຳນົດໄວ້.
|
lo
|
Accreting binaries containing a black hole are stellar systems composed of a normal star and a black hole. Because of the strong gravitational pull of the black hole, matter is removed from the companion star and falls into the compact ob ject. In falling, it forms an accretion disk of gas that spirals towards the center, heating up and emitting in X rays. The physics of such a structure is extremely complex and can be studied through observations with X-ray satellites. The time series derived from X-ray observations of bright black-hole binaries in the Galaxy show a complex phenomenology. Broad noise components with a variability of up to 40% are observed, as well as quasi-periodic features on time scales from 100 seconds down to a few milliseconds. The characteristic frequencies of the different components can change on very short time scales. However, some of these signals are elusive as they are very weak and are drowned in intrinsic and instrumental noise. The physical nature of these signals is still largely unknown, but it is clear that they originate from gas orbiting a few kilometers from the central black hole and accreting onto it. In addition of being important for the study of the accretion of matter onto a black hole, these observational properties constitute a unique probe for testing General Relativity in the strong field regime. I review the current observational status as well as the techniques used to study these signals.
|
အမှောင်တွင်းပါဝင်သော နီးကပ်တွဲဖက်ကြယ်များသည် ပုံမှန်ကြယ်တစ်လုံးနှင့် အမှောင်တွင်းတစ်လုံးပါဝင်သည့် ကြယ်စနစ်များဖြစ်သည်။ အမှောင်တွင်း၏ အင်အားကြီးသော ဆွဲအားကြောင့် အတွဲကြယ်မှ ဒြပ်စင်များ ဖယ်ရှားခံရပြီး စုပ်ယူမှုရှိသည့် အရာဝတ္ထုသို့ ကျဆင်းသွားသည်။ ကျဆင်းလာစဉ်တွင် ဗဟိုသို့ ကွေးကောက်၍ လှည့်ပတ်သော ဓာတ်ငွေ့ဒီစ်ကို ဖြစ်ပေါ်စေပြီး အပူချိန်မြင့်တက်ကာ အက်စ်-ရေးများကို ထုတ်လွှတ်သည်။ ထိုကဲ့သို့သော ဖွဲ့စည်းပုံ၏ ရူပဗေဒသည် အလွန်ရှုပ်ထွေးပြီး အက်စ်-ရေး ဂြိုဟ်တုများဖြင့် စူးစမ်းလေ့လာနိုင်သည်။ ကျွန်ုပ်တို့၏ ကြယ်စုတန်းအတွင်းရှိ အလင်းရောင်အမှောင်တွင်းတွဲဖက်များကို အက်စ်-ရေးဖြင့် စူးစမ်းလေ့လာခြင်းမှ ရရှိသော အချိန်အတိုင်းအတာများသည် ရှုပ်ထွေးသော ဖြစ်စဉ်များကို ပြသသည်။ အများဆုံး 40% အထိ ပြောင်းလဲနိုင်သော ကျယ်ပြန့်သည့် အသံစုတ်ယူမှုပါဝင်သော အစိတ်အပိုင်းများနှင့် စက္ကန့် 100 မှ မီလီစက္ကန့်အနည်းငယ်အထိ ကာလများတွင် ကွက်ကွက်တိုး ပုံစံပါရှိသည်။ အစိတ်အပိုင်းများ၏ သီးခြားလက္ခဏာရှိသော ကြိမ်နှုန်းများသည် အလွန်တိုတောင်းသော အချိန်ကာလများအတွင်း ပြောင်းလဲနိုင်သည်။ သို့သော် အချို့သော အချက်အလက်များသည် အလွန်အားနည်းပြီး သဘာဝနှင့် ကိရိယာဆိုင်ရာ အသံစုတ်ယူမှုများအတွင်း နစ်မြုပ်နေသောကြောင့် ဖမ်းဆီးရန် ခက်ခဲသည်။ ထိုအချက်အလက်များ၏ ရူပဗေဒသဘောသည် ယခုအချိန်တွင် အဓိကအားဖြင့် မသိရသေးသော်လည်း ၎င်းတို့သည် ဗဟိုရှိ အမှောင်တွင်းမှ ကီလိုမီတာ အနည်းငယ်အကွာရှိ ကြိတ်ပွဲဝင်နေသော ဓာတ်ငွေ့များမှ မူလကိုင်းနေသည်ဟု သိရသည်။ အမှောင်တွင်းပေါ်သို့ ဒြပ်စင်များ စုပ်ယူခြင်းကို လေ့လာရာတွင် အရေးပါသည့်အပြင် ထိုစူးစမ်းမှုများသည် အားကောင်းသော မ်ိဳင္းဒြပ္ဝတၳဳနယ်ပယ္တွင် ယေဘုယျ ဆာဂျီရီလိုတီကို စမ်းသပ်ရန် ထူးခြားသော လက်နက်ဖြစ်သည်။ ထိုအချက်အလက်များကို လေ့လာရန် အသုံးပြုသော လက်ရှိ စူးစမ်းမှုအခြေအနေနှင့် နည်းလမ်းများကို ပြန်လည်သုံးသပ်ပါသည်။
|
my
|
Scientific research is a continuous process, and the speed of future progress can be estimated by the pace of finding explanations for previous research questions. In this observers based view of stellar pulsation and asteroseismology, we start with the earliest observations of variable stars and the techniques used to observe them. The earliest variable stars were large amplitude, radial pulsators but were followed by other classes of pulsating stars. As the field matured, we outline some cornerstones of research into pulsating star research with an emphasis on changes in observational techniques. Improvements from photographs, to photometry, CCDs, and space telescopes allowed researchers to separate out pulsating stars from other stars with light variations, recognize radial and nonradial pulsation courtesy of increased measurement precision, and then use nonradial pulsations to look inside the stars, which cannot be done any other way. We follow several highlighted problems to show that even with excellent space data, there still may not be quick theoretical explanations. As the result of technical changes, the structure of international organizations devoted to pulsating stars has changed, and an increasing number of conferences specialized to space missions or themes are held. Although there are still many unsolved problems, such as mode identification in non-asymptotic pulsating stars, the large amount of data with unprecedented precision provided by space missions (MOST, CoRoT, Kepler) and upcoming missions allow us to use asteroseismology to its full potential. However, the enormous flow of data will require new techniques to extract the science before the next missions. The future of asteroseismology will be successful if we learn from the past and improve with improved techniques, space missions, and a properly educated new generation.
|
Wissenschaftliche Forschung ist ein kontinuierlicher Prozess, und die Geschwindigkeit künftigen Fortschritts kann anhand des Tempos abgeschätzt werden, mit dem Erklärungen für frühere Forschungsfragen gefunden werden. In diesem beobachterbasierten Überblick über stellare Pulsation und Asteroseismologie beginnen wir mit den frühesten Beobachtungen variabler Sterne und den Methoden, die zur Beobachtung eingesetzt wurden. Die ersten bekannten variablen Sterne waren radiale Pulsatoren mit großer Amplitude, gefolgt von anderen Klassen pulsierender Sterne. Während sich das Forschungsgebiet weiterentwickelte, skizzieren wir einige Meilensteine der Forschung zu pulsierenden Sternen, wobei der Schwerpunkt auf den Veränderungen der Beobachtungstechniken liegt. Verbesserungen von der Fotografie über die Photometrie hin zu CCDs und Weltraumteleskopen ermöglichten es den Forschern, pulsierende Sterne von anderen Sternen mit Helligkeitsänderungen zu unterscheiden, radiale und nicht-radiale Pulsationen dank höherer Messpräzision zu erkennen und anschließend nicht-radiale Pulsationen zu nutzen, um in das Innere der Sterne zu blicken – eine Methode, die auf keine andere Weise möglich ist. Wir verfolgen mehrere herausgehobene Probleme, um zu zeigen, dass selbst bei hervorragenden Weltraumdaten theoretische Erklärungen nicht zwangsläufig schnell vorliegen. Als Ergebnis technischer Fortschritte hat sich die Struktur internationaler Organisationen, die sich pulsierenden Sternen widmen, verändert, und es finden zunehmend mehr Konferenzen statt, die auf bestimmte Weltraummissionen oder Themen spezialisiert sind. Obwohl noch viele ungelöste Probleme bestehen, wie beispielsweise die Modenidentifikation bei nicht-asympotischen pulsierenden Sternen, erlaubt die große Menge an Daten mit beispielloser Präzision, die von Weltraummissionen (MOST, CoRoT, Kepler) bereitgestellt wird – sowie von zukünftigen Missionen –, die Asteroseismologie nun in vollem Umfang zu nutzen. Der enorme Datenfluss wird jedoch neue Techniken erfordern, um die wissenschaftlichen Erkenntnisse zu extrahieren, bevor die nächsten Missionen starten. Die Zukunft der Asteroseismologie wird erfolgreich sein, wenn wir aus der Vergangenheit lernen, uns mit verbesserten Techniken, Weltraummissionen und einer angemessen ausgebildeten neuen Generation weiterentwickeln.
|
de
|
The recurrent nova T Pyxidis (T Pyx) is well known for its small binary separation, its unusually high luminosity in quiescence, and the spectacular Hubble Space Telescope (HST) images of its surrounding remnant. In 2011 April, T Pyx erupted for the first time since 1966. Here we describe HST observations in late 2011 of a transient reflection nebula around the erupting white dwarf (WD). Our observations of this light echo in the pre-existing remnant show that it is dominated by a clumpy ring with a radius of about 5", and an inclination of 30 to 40 degrees, with the eastern edge tilted toward the observer. The delay times between the direct optical light from the central source, and the scattering of this light from dust in several clumps with the same foreground distance as the central source, give a distance to T Pyx of 4.8 +- 0.5 kpc. Given past evidence from two-dimensional optical spectra that the remnant contains a shell-like component, it must actually consist of a ring embedded within a quasi-spherical shell. The large distance of 4.8 kpc supports the contention that T Pyx has an extraordinarily high rate of mass transfer in quiescence, and thus that nova explosions themselves can enhance mass loss from a donor star, and reduce the time between eruptions in a close binary.
|
再发新星T Pyxidis（T Pyx）以其极小的双星间距、宁静期间异常高的光度以及哈勃空间望远镜（HST）拍摄的周围遗迹的壮观图像而著称。2011年4月，T Pyx自1966年以来首次爆发。本文描述了2011年末利用哈勃空间望远镜对爆发白矮星（WD）周围一个瞬态反射星云的观测结果。我们对这一存在于已有遗迹中的光回波的观测表明，其主体结构是一个半径约为5角秒、倾角为30至40度的团块状环，其中东侧边缘朝向观测者倾斜。来自中心源的直接光学辐射与该辐射被若干团块中尘埃散射之间的延迟时间，结合这些团块与中心源处于相同前景距离的假设，得出T Pyx的距离为4.8 ± 0.5 kpc。鉴于以往二维光谱观测证据表明该遗迹包含一个壳层状成分，因此其实际结构应为一个嵌在准球形壳层内的环。4.8 kpc的较大距离支持了T Pyx在宁静期间具有极高物质转移率的观点，从而表明新星爆发本身能够增强伴星的物质损失，并缩短密近双星系统中爆发的间隔时间。
|
zh
|
The $(1+(\lambda,\lambda))$ genetic algorithm, first proposed at GECCO 2013, showed a surprisingly good performance on so me optimization problems. The theoretical analysis so far was restricted to the OneMax test function, where this GA profited from the perfect fitness-distance correlation. In this work, we conduct a rigorous runtime analysis of this GA on random 3-SAT instances in the planted solution model having at least logarithmic average degree, which are known to have a weaker fitness distance correlation. We prove that this GA with fixed not too large population size again obtains runtimes better than $\Theta(n \log n)$, which is a lower bound for most evolutionary algorithms on pseudo-Boolean problems with unique optimum. However, the self-adjusting version of the GA risks reaching population sizes at which the intermediate selection of the GA, due to the weaker fitness-distance correlation, is not able to distinguish a profitable offspring from others. We show that this problem can be overcome by equipping the self-adjusting GA with an upper limit for the population size. Apart from sparse instances, this limit can be chosen in a way that the asymptotic performance does not worsen compared to the idealistic OneMax case. Overall, this work shows that the $(1+(\lambda,\lambda))$ GA can provably have a good performance on combinatorial search and optimization problems also in the presence of a weaker fitness-distance correlation.
|
O algoritmo genético $(1+(\lambda,\lambda))$, inicialmente proposto no GECCO 2013, apresentou um desempenho surpreendentemente bom em alguns problemas de otimização. A análise teórica até agora foi restrita à função teste OneMax, onde esse AG se beneficiou da perfeita correlação entre aptidão e distância. Neste trabalho, realizamos uma análise rigorosa do tempo de execução desse AG em instâncias aleatórias do problema 3-SAT no modelo de solução plantada com grau médio pelo menos logarítmico, os quais se sabe possuem uma correlação entre aptidão e distância mais fraca. Provamos que esse AG com tamanho de população fixo, não muito grande, novamente obtém tempos de execução melhores que $\Theta(n \log n)$, que é um limite inferior para a maioria dos algoritmos evolutivos em problemas pseudo-booleanos com ótimo único. No entanto, a versão com ajuste automático do AG corre o risco de atingir tamanhos de população nos quais a seleção intermediária do AG, devido à correlação mais fraca entre aptidão e distância, não é capaz de distinguir um descendente vantajoso dos demais. Mostramos que esse problema pode ser superado ao dotar o AG com ajuste automático de um limite superior para o tamanho da população. Exceto em instâncias esparsas, esse limite pode ser escolhido de forma que o desempenho assintótico não piore em comparação com o caso idealizado do OneMax. No geral, este trabalho mostra que o AG $(1+(\lambda,\lambda))$ pode comprovadamente ter bom desempenho em problemas de busca e otimização combinatória mesmo na presença de uma correlação mais fraca entre aptidão e distância.
|
pt
|
In this Letter we investigate the properties of advection-dominated accretion flows (ADAFs) fed by the evaporation of a Shakura-Sunyaev accretion disk (SSD). In our picture the ADAF fills the central cavity evacuated by the SSD and extends beyond the transition radius into a coronal region. We find that, because of global angular momentum conservation, a significant fraction of the hot gas flows away from the black hole forming a transsonic wind, unless the injection rate depends only weakly on radius (if $r^2\dot\sigma\propto r^{-\xi}$, $\xi< 1/2$). The Bernoulli number of the inflowing gas is negative if the transition radius is $\lesssim 100$ Schwarzschild radii, so matter falling into the hole is gravitationally bound. The ratio of inflowing to outflowing mass is $\approx 1/2$, so in these solutions the accretion rate is of the same order as in standard ADAFs and much larger than in advection-dominated inflow/outflow models (ADIOS). The possible relevance of evaporation-fed solutions to accretion flows in black hole X-ray binaries is briefly discussed.
|
本文研究了由Shakura-Sunyaev吸积盘（SSD）蒸发所提供物质的以对流为主导的吸积流（ADAF）的性质。在我们的模型中，ADAF填充了SSD清空的中心空腔，并延伸至过渡半径以外的冕区。我们发现，由于整体角动量守恒，除非物质注入率对半径的依赖较弱（若 $r^2\dot\sigma\propto r^{-\xi}$，则 $\xi< 1/2$），否则有相当一部分热气体将远离黑洞形成跨声速风。若过渡半径小于约100倍史瓦西半径，则流入气体的伯努利数为负，表明落入黑洞的物质在引力上是束缚的。流入与流出的质量之比约为1/2，因此在这些解中，吸积率与标准ADAF相当，远大于对流主导的流入/流出模型（ADIOS）中的吸积率。本文简要讨论了由蒸发供能的解在黑洞X射线双星吸积流中的可能应用。
|
zh
|
Given two spherically symmetric and short range potentials $V_0$ and V_1 for which the radial Schrodinger equation can be solved explicitely at zero energy, we show how to construct a new potential $V$ for which the radial equation can again be solved explicitely at zero energy. The new potential and its corresponding wave function are given explicitely in terms of V_0 and V_1, and their corresponding wave functions \phi_0 and \phi_1. V_0 must be such that it sustains no bound states (either repulsive, or attractive but weak). However, V_1 can sustain any (finite) number of bound states. The new potential V has the same number of bound states, by construction, but the corresponding (negative) energies are, of course, different. Once this is achieved, one can start then from V_0 and V, and construct a new potential \bar{V} for which the radial equation is again solvable explicitely. And the process can be repeated indefinitely. We exhibit first the construction, and the proof of its validity, for regular short range potentials, i.e. those for which rV_0(r) and rV_1(r) are L^1 at the origin. It is then seen that the construction extends automatically to potentials which are singular at r= 0. It can also be extended to V_0 long range (Coulomb, etc.). We give finally several explicit examples.
|
দুটি গোলাকারভাবে প্রতিসম এবং স্বল্প-পাল্লার বিভব $V_0$ এবং $V_1$ দেওয়া হলে, যাদের জন্য শূন্য শক্তিতে বিকিরণীয় শ্রোডিঞ্জার সমীকরণ স্পষ্টভাবে সমাধান করা যায়, আমরা দেখাই কিভাবে একটি নতুন বিভব $V$ গঠন করা যায় যার জন্য শূন্য শক্তিতে আবার বিকিরণীয় সমীকরণটি স্পষ্টভাবে সমাধানযোগ্য হবে। নতুন বিভব এবং তার অনুরূপ তরঙ্গ অপেক্ষকগুলি $V_0$, $V_1$ এবং তাদের অনুরূপ তরঙ্গ অপেক্ষক $\phi_0$ এবং $\phi_1$-এর পদে স্পষ্টভাবে দেওয়া হয়। $V_0$ এমন হতে হবে যে এটি কোনো বদ্ধ অবস্থা ধারণ করে না (হয় বিকর্ষণমূলক, অথবা আকর্ষণমূলক কিন্তু দুর্বল)। তবে $V_1$ যেকোনো (সসীম) সংখ্যক বদ্ধ অবস্থা ধারণ করতে পারে। নতুন বিভব $V$-এর বদ্ধ অবস্থার সংখ্যা গঠনের কারণে একই থাকে, কিন্তু অনুরূপ (ঋণাত্মক) শক্তিগুলি অবশ্যই ভিন্ন হয়। এটি একবার সম্পন্ন হলে, এরপর $V_0$ এবং $V$ থেকে শুরু করে আমরা একটি নতুন বিভব $\bar{V}$ গঠন করতে পারি যার জন্য বিকিরণীয় সমীকরণটি আবার স্পষ্টভাবে সমাধানযোগ্য হয়। এবং এই প্রক্রিয়াটি অনির্দিষ্টকালের জন্য পুনরাবৃত্তি করা যায়। আমরা প্রথমে নিয়মিত স্বল্প-পাল্লার বিভবের জন্য গঠন পদ্ধতি এবং এর বৈধতার প্রমাণ উপস্থাপন করি, অর্থাৎ যেসব বিভবের জন্য $rV_0(r)$ এবং $rV_1(r)$ মূলবিন্দুতে $L^1$। তারপর দেখা যায় যে গঠনটি স্বয়ংক্রিয়ভাবে $r=0$-এ সিঙ্গুলার বিভবগুলির ক্ষেত্রে প্রসারিত হয়। এটি $V_0$ দীর্ঘ-পাল্লার (কুলম্ব, ইত্যাদি) ক্ষেত্রেও প্রসারিত করা যায়। অবশেষে আমরা বেশ কয়েকটি স্পষ্ট উদাহরণ দিই।
|
bn
|
If the early optical data of GRB 060218 up to 1e5 s are interpreted as the black-body flux associated with the supernova shock breakout, we can derive lower limits to the bolometric luminosity and energetics of this black-body component. These limits are more severe for the very early data that imply energetics of order of 1e51 erg. These values, puzzlingly large, are rather independent of the assumed time profile of the emitting surface, provided that the corresponding radius does not increase superluminally. Another concern is the luminosity of the black-body component observed in the X-rays, that is large and appears to be produced by an approximately constant temperature and a surface area increasing only slowly in time. Although it has been suggested that the long X-ray black-body duration is consistent with the supernova shock breakout if anisotropy is assumed, the nearly constant emitting surface requires some fine tuning, allowing and suggesting an alternative interpretation, i.e. emission from late dissipation of the fireball bulk kinetic energy. This in turn requires a small value of the bulk Lorentz factor.
|
Егершегі 060218-дің 1e5 с-қа дейінгі бастапқы оптикалық деректерін супернова соққысының шығуымен байланысты қара дене ағыны ретінде түсіндірсек, бұл қара дене компонентінің болометрлік жарқырауы мен энергетикасы үшін төменгі шектерді алуға болады. Бұл шектер өте ерте деректер үшін тиімдірек және энергетиканың 1e51 эрг шамасындағы ретін білдіреді. Бұл мәндер түсініксіз дәрежеде үлкен және сәулелендіруші беттің болжанған уақыт профиліне тәуелсіз, егер сәйкес келетін радиус супержарықтықтан артық өспесе. Тағы бір мәселе – рентген сәулелерінде байқалатын қара дене компонентінің жарқырауы, ол үлкен және тұрақты температура мен уақыт өте баяу ғана өсетін бет ауданы арқылы туындайтындай көрінеді. Рентген сәулелеріндегі қара дененің ұзақ уақыт созылуы анізотропия болжанған жағдайда супернова соққысының шығуымен сәйкес келеді деп ұсынылған болса да, сәулелендіруші беттің тұрақтылығы кейбір дәл баптауды қажет етеді және басқа түсіндіруді, яғни от шарының көптеген кинетикалық энергиясының кейінгі диссипациясынан туындайтын сәулеленуді ұсынады. Бұл өз кезегінде көптеген Лоренц факторының аз мәнін талап етеді.
|
kk
|
We provide the first direct observations of interstellar H+ and He+ pickup ions in the solar wind from 22 AU to 38 AU. We use the Vasyliunas and Siscoe model functional form to quantify the pickup ion distributions, and while the fit parameters generally lie outside their physically expected ranges, this form allows fits that quantify variations in the pickup H+ properties with distance. By ~20 AU, the pickup ions already provide the dominant internal pressure in the solar wind. We determine the radial trends and extrapolate them to the termination shock at ~90 AU, where the pickup H+ to core solar wind density reaches ~0.14. The pickup H+ temperature and thermal pressure increase from 22-38 AU, indicating additional heating of the pickup ions. This produces very large extrapolated ratios of pickup H+ to solar wind temperature and pressure and an extrapolated ratio of the pickup ion pressure to the solar wind dynamic pressure at the termination shock of ~0.16. Such a large ratio has profound implications for moderating the termination shock and the overall outer heliospheric interaction. We also identify suprathermal tails in the H+ spectra and complex features in the He+ spectra, likely indicating variations in the pickup ion history and processing. Finally, we discover enhancements in both H+ and He+ populations just below their cutoff energies, which may be associated with enhanced local pickup. This study serves to document the release and as the citable reference of these pickup ion data for broad community use and analysis.
|
ہم 22 AU سے 38 AU تک سورجی ہوا میں بین النجومی H+ اور He+ پک اپ آئنز کے پہلے براہ راست مشاہدات فراہم کرتے ہیں۔ ہم پک اپ آئن تقسیم کی مقداری کیفیت کے لیے واسیلیونس اور سسکو ماڈل فنکشنل فارم کا استعمال کرتے ہیں، اور اگرچہ فٹ پیرامیٹرز عموماً ان کی جسمانی طور پر متوقع حدود کے باہر ہوتے ہیں، تاہم یہ شکل ان فٹس کی اجازت دیتی ہے جو فاصلے کے ساتھ پک اپ H+ خواص میں تبدیلیوں کی مقداری کیفیت کرتی ہیں۔ تقریباً 20 AU تک، پک اپ آئنز پہلے ہی سورجی ہوا میں غالب داخلی دباؤ فراہم کرتے ہیں۔ ہم شعاعی رجحانات کا تعین کرتے ہیں اور انہیں تقریباً 90 AU پر ختم ہونے والے دباؤ تک پھیلاتے ہیں، جہاں پک اپ H+ سے بنیادی سورجی ہوا کی کثافت تقریباً 0.14 تک پہنچ جاتی ہے۔ 22 سے 38 AU تک پک اپ H+ کا درجہ حرارت اور حرارتی دباؤ میں اضافہ ہوتا ہے، جو پک اپ آئنز کی اضافی گرمی کی نشاندہی کرتا ہے۔ اس سے پک اپ H+ اور سورجی ہوا کے درجہ حرارت اور دباؤ کے انتہائی بڑے پھیلاؤ والے تناسب اور ختم ہونے والے دباؤ پر پک اپ آئن دباؤ کا سورجی ہوا کے متحرک دباؤ سے تقریباً 0.16 کا پھیلاؤ والے تناسب کا اندازہ لگایا جاتا ہے۔ اس قدر بڑا تناسب ختم ہونے والے دباؤ کو منظم کرنے اور مجموعی طور پر بیرونی ہیلیوسفیرک تعامل کے لیے گہرے اثرات رکھتا ہے۔ ہم H+ اسپیکٹرا میں سپرا تھرمل دُم اور He+ اسپیکٹرا میں پیچیدہ خصوصیات بھی پہچانتے ہیں، جو احتمالاً پک اپ آئنز کی تاریخ اور پروسیسنگ میں تبدیلی کی نشاندہی کرتی ہیں۔ آخر میں، ہم اپنی حد توانائیوں سے تھوڑا کم دونوں H+ اور He+ آبادیوں میں اضافے دریافت کرتے ہیں، جو مقامی طور پر بڑھے ہوئے پک اپ سے منسلک ہو سکتے ہیں۔ یہ مطالعہ پک اپ آئنز کے ان ڈیٹا کو ریکارڈ کرنے اور انہیں وسیع کمیونٹی کے استعمال اور تجزیہ کے لیے حوالہ جاتی حوالہ کے طور پر پیش کرنے کا کام انجام دیتا ہے۔
|
ur
|
We compare the properties of stellar populations of model galaxies from the Cosmic Reionization On Computers (CROC) project with the exiting UV and IR data. Since CROC simulations do not follow cosmic dust directly, we adopt two variants of the dust-follows-metals ansatz to populate model galaxies with dust. Using the dust radiative transfer code Hyperion, we compute synthetic stellar spectra, UV continuum slopes, and IR fluxes for simulated galaxies. We find that the simulation results generally match observational measurements, but, perhaps, not in full detail. The differences seem to indicate that our adopted dust-follows-metals ansatzes are not fully sufficient. While the discrepancies with the exiting data are marginal, the future JWST data will be of much higher precision, rendering highly significant any tentative difference between theory and observations. It is, therefore, likely, that in order to fully utilize the precision of JWST observations, fully dynamical modeling of dust formation, evolution, and destruction may be required.
|
Porovnáváme vlastnosti hvězdných populací galaxií z modelu projektu Cosmic Reionization On Computers (CROC) s dostupnými daty v ultrafialovém a infračerveném oboru. Jelikož simulace CROC nepopisují vývoj kosmického prachu přímo, používáme dva varianty předpokladu, že prach sleduje kovy, za účelem doplnění modelových galaxií o prach. Pomocí kódu pro přenos záření Hyperion vypočítáváme syntetická hvězdná spektra, sklon ultrafialového kontinua a infračervené toky pro simulované galaxie. Zjistili jsme, že výsledky simulací obecně odpovídají pozorovacím měřením, ale možná ne zcela detailně. Rozdíly naznačují, že naše použité varianty předpokladu, že prach sleduje kovy, nejsou plně dostačující. Ačkoli se rozdíly s dostupnými daty jeví jako nepatrné, budoucí data z JWST budou mnohem přesnější a jakýkoli náznak rozdílu mezi teorií a pozorováními bude statisticky významný. Je proto pravděpodobné, že pro plné využití přesnosti pozorování JWST bude nutné provádět plně dynamické modelování tvorby, vývoje a zániku prachu.
|
cs
|
Let A be a C*-algebra and A** its enveloping von Neumann algebra. C. Akemann suggested a kind of non-commutative topology in which certain projections in A** play the role of open sets. The adjectives "open", "closed", "compact", and "relatively compact" all can be applied to projections in A**. Two operator inequalities were used by Akemann in connection with compactness. Both of these inequalities are equivalent to compactness for a closed projection in A**, but only one is equivalent to relative compactness for a general projection. A third operator inequality, also related to compactness, was used by the author. It turns out that the study of all three inequalities can be unified by considering a numerical invariant which is equivalent to the distance of a projection from the set of relatively compact projections. Since the subject concerns the relation between a projection and its closure, Tomita's concept of regularity of projections seems relevant, and some results and examples on regularity are also given. A few related results on semicontinuity are also included.
|
Sea A una C*-álgebra y A** su álgebra de von Neumann envolvente. C. Akemann sugirió un tipo de topología no conmutativa en la que ciertas proyecciones en A** desempeñan el papel de conjuntos abiertos. Los adjetivos "abierta", "cerrada", "compacta" y "relativamente compacta" pueden aplicarse a proyecciones en A**. Akemann utilizó dos desigualdades operatoriales en relación con la compacidad. Ambas desigualdades son equivalentes a la compacidad para una proyección cerrada en A**, pero solo una de ellas es equivalente a la compacidad relativa para una proyección general. El autor empleó una tercera desigualdad operatorial, también relacionada con la compacidad. Resulta que el estudio de las tres desigualdades puede unificarse considerando un invariante numérico que equivale a la distancia de una proyección al conjunto de las proyecciones relativamente compactas. Dado que el tema trata sobre la relación entre una proyección y su clausura, el concepto de Tomita sobre regularidad de proyecciones parece relevante, y se incluyen algunos resultados y ejemplos sobre regularidad. También se incluyen algunos resultados relacionados sobre semicontinuidad.
|
es
|
With the aim of better understanding the class of 4D theories generated by compactifications of 6D superconformal field theories (SCFTs), we study the structure of N = 1 supersymmetric punctures for class S_Gamma theories, namely the 6D SCFTs obtained from M5-branes probing an ADE singularity. For M5-branes probing a C^2 / Z_k singularity, the punctures are governed by a dynamical system in which evolution in time corresponds to motion to a neighboring node in an affine A-type quiver. Classification of punctures reduces to determining consistent initial conditions which produce periodic orbits. The study of this system is particularly tractable in the case of a single M5-brane. Even in this "simple" case, the solutions exhibit a remarkable level of complexity: Only specific rational values for the initial momenta lead to periodic orbits, and small perturbations in these values lead to vastly different late time behavior. Another difference from half BPS punctures of class S theories includes the appearance of a continuous complex "zero mode" modulus in some puncture solutions. The construction of punctures with higher order poles involves a related set of recursion relations. The resulting structures also generalize to systems with multiple M5-branes as well as probes of D- and E-type orbifold singularities.
|
Dans le but de mieux comprendre la classe de théories en 4D obtenues par compactification de théories conformes supersymétriques en 6D (SCFT), nous étudions la structure des perforations supersymétriques avec N = 1 pour les théories de classe S_Gamma, à savoir les SCFT en 6D obtenues à partir de M5-branes sondant une singularité de type ADE. Pour des M5-branes sondant une singularité C^2 / Z_k, les perforations sont régies par un système dynamique dans lequel l'évolution temporelle correspond à un déplacement vers un nœud voisin dans un carquois affine de type A. La classification des perforations se ramène à la détermination de conditions initiales cohérentes produisant des orbites périodiques. L'étude de ce système est particulièrement accessible dans le cas d'une seule M5-brane. Même dans ce cas « simple », les solutions présentent un niveau remarquable de complexité : seules certaines valeurs rationnelles spécifiques des impulsions initiales conduisent à des orbites périodiques, et de petites perturbations de ces valeurs entraînent des comportements très différents à grand temps. Une autre différence par rapport aux perforations demi-BPS des théories de classe S réside dans l'apparition d'un module continu complexe de « mode zéro » dans certaines solutions de perforation. La construction de perforations ayant des pôles d'ordre supérieur implique un ensemble de relations de récurrence associées. Les structures obtenues se généralisent également à des systèmes comportant plusieurs M5-branes ainsi qu'à des sondes de singularités orbifolds de type D et E.
|
fr
|
We have obtained an exceptionally high S/N, high resolution spectrum of the gravitationally lensed quasar Q1422+231 in order to investigate the metal enrichment of the IGM. A column density distribution function (CDDF) is determined for CIV, which is well fit by a power law with index 1.44 +/- 0.05. Once a correction for incompleteness is applied, we find that the CDDF is consistent with a power law down to log N(CIV) = 11.75, a factor of 10 more sensitive than previously determined. In order to determine whether the CIV enrichment extends to even lower column density HI clouds, we find that an analysis of individual pixel optical depths is more robust than the stacking technique. The results obtained from this optical depth method are compared with analyses of simulated spectra enriched with varying CIV enrichment recipes. From these simulations, we conclude that more CIV than is currently directly detected in Q1422+231 is required to reproduce the optical depths determined from the data, consistent with the conclusions drawn from consideration of the power law distribution. (Abridged)
|
重力レンズ効果を受けたクエーサーQ1422+231について、異常に高いS/N比と高分解能のスペクトルを得て、IGMの金属元素の豊かさを調査した。CIVについての柱密度分布関数（CDDF）を求めたところ、指数1.44±0.05のべき乗則でよくフィットされた。検出の不完全性に対する補正を適用した後、CDDFはlog N(CIV) = 11.75までべき乗則に従っていることがわかった。これは従来の結果と比べて10倍感度が向上している。CIVの豊かさがさらに低い柱密度のHI雲まで及んでいるかどうかを判断するため、積み重ね法よりも個々のピクセルの光学的深さを解析する方法がより信頼性が高いことがわかった。この光学的深さ法で得られた結果を、異なるCIV豊かさのシナリオで豊かさを与えた模擬スペクトルの解析結果と比較した。これらのシミュレーションから、Q1422+231で現在直接検出されている量よりも多くのCIVが存在しなければ、観測データから得られた光学的深さを再現できないことが明らかになり、これはべき乗則分布の考察から得られた結論と一致している。（要約）
|
ja
|
One of the major targets for next-generation cosmic microwave background (CMB) experiments is the detection of the primordial B-mode signal. Planning is under way for Stage-IV experiments that are projected to have instrumental noise small enough to make lensing and foregrounds the dominant source of uncertainty for estimating the tensor-to-scalar ratio $r$ from polarization maps. This makes delensing a crucial part of future CMB polarization science. In this paper we present a likelihood method for estimating the tensor-to-scalar ratio $r$ from CMB polarization observations, which combines the benefits of a full-scale likelihood approach with the tractability of the quadratic delensing technique. This method is a pixel space, all order likelihood analysis of the quadratic delensed B modes, and it essentially builds upon the quadratic delenser by taking into account all order lensing and pixel space anomalies. Its tractability relies on a crucial factorization of the pixel space covariance matrix of the polarization observations which allows one to compute the full Gaussian approximate likelihood profile, as a function of $r$, at the same computational cost of a single likelihood evaluation.
|
ໜຶ່ງໃນເປົ້າໝາຍຫຼັກຂອງການທົດລອງດ້ານພື້ນທີ່ມິກໂຣເວຟຂອງຈັກກະວານ (CMB) ລຸ້ນຕໍ່ໄປແມ່ນການກວດພົບສັນຍານ B-mode ແບບດັ້ງເດີມ. ການວາງແຜນກຳລັງດຳເນີນຢູ່ສຳລັບການທົດລອງຂັ້ນຕອນທີ່ IV ທີ່ຄາດວ່າຈະມີສຽງຮົບກວນຈາກເຄື່ອງມືທີ່ນ້ອຍພໍທີ່ຈະເຮັດໃຫ້ການເບິ່ງເຫັນຜ່ານເລນແລະສິ່ງກີດຂວາງເປັນແຫຼ່ງຂອງຄວາມບໍ່ແນ່ນອນທີ່ສຳຄັນທີ່ສຸດໃນການຄາດຄະເນອັດຕາສ່ວນເທັນເຊີ-ຕໍ່-ສະແກນເລີ $r$ ຈາກແຜນທີ່ການຂັ້ວ. ສິ່ງນີ້ເຮັດໃຫ້ການຖອດເລນ (delensing) ເປັນສ່ວນໜຶ່ງທີ່ສຳຄັນຫຼາຍໃນວິທະຍາສາດການຂັ້ວຂອງ CMB ທີ່ຈະມາເຖິງ. ໃນບົດຄວາມນີ້ ພວກເຮົານຳສະເໜີວິທີການຄວາມໜ້າຈະເປັນ (likelihood) ສຳລັບການຄາດຄະເນອັດຕາສ່ວນເທັນເຊີ-ຕໍ່-ສະແກນເລີ $r$ ຈາກການສັງເກດການຂັ້ວຂອງ CMB, ເຊິ່ງປະສົມຜົນປະໂຫຍດຂອງວິທີການຄວາມໜ້າຈະເປັນຂະໜາດໃຫຍ່ເຂົ້າກັບຄວາມເປັນໄປໄດ້ຂອງວິທີການຖອດເລນແບບ quadratic. ວິທີການນີ້ແມ່ນການວິເຄາະຄວາມໜ້າຈະເປັນທີ່ມີຄຳສັ່ງທັງໝົດໃນພື້ນທີ່ພິກເຊວ (pixel space) ຂອງ B modes ທີ່ຖືກຖອດເລນແບບ quadratic, ແລະ ມັນຖືກສ້າງຕັ້ງຂື້ນໂດຍອີງໃສ່ເຄື່ອງມືຖອດເລນແບບ quadratic ໂດຍການຄຳນຶງເຖິງການເບິ່ງເຫັນຜ່ານເລນທຸກຄຳສັ່ງ ແລະ ຄວາມຜິດປົກກະຕິໃນພື້ນທີ່ພິກເຊວ. ຄວາມເປັນໄປໄດ້ຂອງມັນຂື້ນກັບການປັດສະຈຳທີ່ສຳຄັນຂອງແມັດຕິກຄວາມແປປວນໃນພື້ນທີ່ພິກເຊວຂອງການສັງເກດການຂັ້ວ ເຊິ່ງອະນຸຍາດໃຫ້ຄົນໆໜຶ່ງຄຳນວນໂປຣໄຟລ໌ຄວາມໜ້າຈະເປັນປະມານ Gaussian ທັງໝົດ ເປັນຟັງຊັ້ນຂອງ $r$, ດ້ວຍຕົ້ນທຶນດ້ານການຄຳນວນທີ່ເທົ່າກັບການປະເມີນຄວາມໜ້າຈະເປັນຄັ້ງດຽວ.
|
lo
|
We present the first spectral features obtained from Cassini's Composite Infrared Spectrometer (CIRS) for any icy moon. The spectral region covered by CIRS focal planes (FP) 3 and 4 is rich in emissivity features, but previous studies at these wavelengths have been limited by low signal to noise ratios (S/Rs) for individual spectra. Our approach is to average CIRS FP3 spectra to increase the S/R and use emissivity spectra to constrain the composition of the dark material on Iapetus. We find an emissivity feature at ~855 cm-1 and a possible doublet at 660 and 690 cm-1 that do not correspond to any known instrument artifacts. We attribute the 855 cm-1 feature to fine-grained silicates, similar to those found in dust on Mars and in meteorites, which are nearly featureless at shorter wavelengths. Silicates on the dark terrains of Saturn's icy moons have been suspected for decades, but there have been no definitive detections until now. Serpentines reported in the literature at ambient temperature and pressure have features near 855 and 660 cm-1. However, peaks can shift depending on temperature and pressure, so measurements at Iapetus-like conditions are necessary for more positive feature identifications. As a first investigation, we measured muscovite at 125K in a vacuum and found that this spectrum does match the emissivity feature near 855 cm-1 and the location of the doublet. Further measurements are needed to robustly identify a specific silicate, which would provide clues regarding the origin and implications of the dark material.
|
Біз кез-келген мұзды серіктің Кассини космостық аппаратының комбинирленген инфрақызыл спектрометрі (CIRS) арқылы алынған алғашқы спектрлік сипаттамаларын ұсынамыз. CIRS-тің фокустық жазықтықтарының (FP) 3 және 4 қамтитын спектрлік аймақ шығару сипаттамаларымен бай, бірақ бұл толқын ұзындықтары бойынша жүргізілген бұрынғы зерттеулер жеке спектрлер үшін төменгі сигнал/дәрілік қатынастарымен (S/R) шектелді. Біздің әдісіміз S/R-ді арттыру үшін CIRS FP3 спектрлерін орташа есептеу және Япеттің қара материалдарының құрамын шектеу үшін шығару спектрлерін қолдану. Біз 855 см-1 маңында және 660 және 690 см-1-де мүмкін болатын екі еселік табуға тиісті, бұл кез-келген белгілі аспаптық қисынсыздықтарға сәйкес келмейтін шығару сипаттамасын таптық. Біз 855 см-1 сипаттамасын Марстағы шаң мен метеориттерде табылған және қысқа толқын ұзындықтарында түбірі шығарылмайтын саздық минералдарға ұқсас, ұсақ түйіршікті силикаттарға байланыстырамыз. Силикаттар Сатурнның мұзды серіктерінің қара аймақтарында ондаған жылдар бойы шектеліп келді, бірақ әлі күнге дейін олардың анық анықталуы болған жоқ. Әдебиетте қалыпты температура мен қысымда серпентиндер 855 және 660 см-1 маңында сипаттамалары бар деп хабарланады. Алайда, пиктер температура мен қысымға байланысты ығысуы мүмкін, сондықтан Япетке тән жағдайларда өлшеулер сипаттамаларды дәл анықтау үшін қажет. Бірінші зерттеу ретінде біз 125K температурада вакуумда мусковитті өлшеп, осы спектрдің 855 см-1 маңындағы шығару сипаттамасына және екі еселіктің орнына сәйкес келетінін анықтадық. Нақты силикатты анықтау үшін одан әрі өлшеулер қажет, бұл қара материалдардың шығу тегі мен маңызы туралы кілттік көрсеткіштерді береді.
|
kk
|
Kundt spacetimes are of great importance in general relativity in 4 dimensions and have a number of topical applications in higher dimensions in the context of string theory. The degenerate Kundt spacetimes have many special and unique mathematical properties, including their invariant curvature structure and their holonomy structure. We provide a rigorous geometrical kinematical definition of the general Kundt spacetime in 4 dimensions; essentially a Kundt spacetime is defined as one admitting a null vector that is geodesic, expansion-free, shear-free and twist-free. A Kundt spacetime is said to be degenerate if the preferred kinematic and curvature null frames are all aligned. The degenerate Kundt spacetimes are the only spacetimes in 4 dimensions that are not $\mathcal{I}$-non-degenerate, so that they are not determined by their scalar polynomial curvature invariants. We first discuss the non-aligned Kundt spacetimes, and then turn our attention to the degenerate Kundt spacetimes. The degenerate Kundt spacetimes are classified algebraically by the Riemann tensor and its covariant derivatives in the aligned kinematic frame; as an example, we classify Riemann type D degenerate Kundt spacetimes in which $\nabla(Riem),\nabla^{(2)}(Riem)$ are also of type D. We discuss other local characteristics of the degenerate Kundt spacetimes. Finally, we discuss degenerate Kundt spacetimes in higher dimensions.
|
Kundt uzayzamanları, 4 boyutta genel görelilikte büyük öneme sahiptir ve dize kuramı bağlamında daha yüksek boyutlarda çeşitli güncel uygulamalara sahiptir. Yozlaşmış Kundt uzayzamanlarının, değişmez eğrilik yapısı ve holonomi yapısı da dahil olmak üzere birçok özel ve benzersiz matematiksel özelliği vardır. Genel Kundt uzayzamanının katı bir geometrik kinematik tanımını 4 boyutta sunuyoruz; temelde Kundt uzayzamanı, jeodezik, genişlemesiz, kesme-yok ve burulmasız olan bir null vektör kabul eden uzayzaman olarak tanımlanır. Tercih edilen kinematik ve eğrilik null çatılarının hepsinin hizalanması durumunda Kundt uzayzamanına yozlaşmış denir. Yozlaşmış Kundt uzayzamanları, 4 boyutta $\mathcal{I}$-yozlaşmamış olmayan tek uzayzamanlardır; bu yüzden skaler polinom eğrilik değişmezleriyle belirlenemezler. Önce hizalanmamış Kundt uzayzamanlarını tartışıyoruz, sonra dikkatimizi yozlaşmış Kundt uzayzamanlarına çeviriyoruz. Yozlaşmış Kundt uzayzamanları, hizalanmış kinematik çatıda Riemann tensörü ve kovaryant türevleri açısından cebirsel olarak sınıflandırılır; bir örnek olarak, $\nabla(Riem)$ ve $\nabla^{(2)}(Riem)$ tensörlerinin de tip D olduğu Riemann tip D yozlaşmış Kundt uzayzamanlarını sınıflandırıyoruz. Yozlaşmış Kundt uzayzamanlarının diğer yerel özelliklerini tartışıyoruz. Son olarak, daha yüksek boyutlardaki yozlaşmış Kundt uzayzamanlarını tartışıyoruz.
|
tr
|
The multiscale approach to N-body systems is generalized to address the broad continuum of long time and length scales associated with collective behaviors. A technique is developed based on the concept of an uncountable set of time variables and of order parameters (OPs) specifying major features of the system. We adopt this perspective as a natural extension of the commonly used discrete set of timescales and OPs which is practical when only a few, widely-separated scales exist. The existence of a gap in the spectrum of timescales for such a system (under quasiequilibrium conditions) is used to introduce a continuous scaling and perform a multiscale analysis of the Liouville equation. A functional-differential Smoluchowski equation is derived for the stochastic dynamics of the continuum of Fourier component order parameters. A continuum of spatially non-local Langevin equations for the OPs is also derived. The theory is demonstrated via the analysis of structural transitions in a composite material, as occurs for viral capsids and molecular circuits.
|
ການເຂົ້າໃກ້ລະດັບຂອງລະບົບ N-body ແມ່ນຖືກກະຈາຍອອກເພື່ອຈັດການກັບຊ່ວງກາງທີ່ກວ້າງຂວາງຂອງໄລຍະເວລາ ແລະ ຄວາມຍາວທີ່ກ່ຽວຂ້ອງກັບພຶດຕິກຳກຸ່ມ. ເຕັກນິກໜຶ່ງຖືກພັດທະນາຂຶ້ນໂດຍອີງໃສ່ແນວຄິດຂອງຊຸດຂອງຕົວປ່ຽນເວລາທີ່ບໍ່ສາມາດນັບໄດ້ ແລະ ຕົວກຳນົດລຳດັບ (OPs) ທີ່ກຳນົດລັກສະນະຫຼັກໆຂອງລະບົບ. ພວກເຮົານຳເອົາມຸມມອງນີ້ມາໃຊ້ເປັນການຂະຫຍາຍທຳມະດາຂອງຊຸດຂອງຂະໜາດເວລາ ແລະ OPs ທີ່ຖືກນຳໃຊ້ຢ່າງກວ້າງຂວາງ ເຊິ່ງເປັນໄປໄດ້ຈິງເມື່ອມີພຽງບໍ່ຫຼາຍປານໃດ ແລະ ຂະໜາດທີ່ແຍກອອກໄປຢ່າງກວ້າງຂວາງ. ການມີຢູ່ຂອງຊ່ອງຫວ່າງໃນສະເປັກຕຼັມຂອງຂະໜາດເວລາສຳລັບລະບົບດັ່ງກ່າວ (ພາຍໃຕ້ເງື່ອນໄຂຄວາມສົມດຸນທີ່ເກືອບຈະເປັນຈິງ) ແມ່ນຖືກນຳໃຊ້ເພື່ອນຳສະເໜີການຂະຫຍາຍຕົວຢ່າງຕໍ່ເນື່ອງ ແລະ ດຳເນີນການວິເຄາະລະດັບຂອງສົມຜົນ Liouville. ສົມຜົນ Smoluchowski ທີ່ເປັນຟັງຊັ້ນ-ຄຳແນະນຳຖືກສະຫຼຸບສຳລັບພຶດຕິກຳສຸ່ມຂອງຊຸດຂອງຕົວກຳນົດລຳດັບສ່ວນປະກອບຟູເຣີຢ. ສົມຜົນ Langevin ທີ່ບໍ່ມີທ້ອງຖິ່ນຢ່າງຕໍ່ເນື່ອງສຳລັບ OPs ກໍຖືກສະຫຼຸບດ້ວຍ. ທິດສະດີນີ້ຖືກສະແດງອອກຜ່ານການວິເຄາະການຖ່າຍໂອນໂຄງສ້າງໃນວັດສະດຸປະສົມ, ເຊັ່ນດຽວກັບທີ່ເກີດຂຶ້ນກັບກ້ອງກັບກັ້ນໄວຮັດ ແລະ ລວດຟ້າວໂມເລກຸນ.
|
lo
|
The neutron-rich 6He and 8He isotopes exhibit an exotic nuclear structure that consists of a tightly bound 4He-like core with additional neutrons orbiting at a relatively large distance, forming a halo. Recent experimental efforts have succeeded in laser trapping and cooling these short-lived, rare helium atoms, and have measured the atomic isotope shifts along the 4He-6He-8He chain by performing laser spectroscopy on individual trapped atoms. Meanwhile, the few-electron atomic structure theory, including relativistic and QED corrections, has reached a comparable degree of accuracy in the calculation of the isotope shifts. In parallel efforts, also by measuring atomic isotope shifts, the nuclear charge radii of lithium and beryllium isotopes have been studied. The techniques employed were resonance ionization spectroscopy on neutral, thermal lithium atoms and collinear laser spectroscopy on beryllium ions. Combining advances in both atomic theory and laser spectroscopy, the charge radii of these light halo nuclei have now been determined for the first time independent of nuclear structure models. The results are compared with the values predicted by a number of nuclear structure calculations, and are used to guide our understanding of the nuclear forces in the extremely neutron-rich environment.
|
Isotop 6He dan 8He yang kaya dengan neutron menunjukkan struktur nuklear yang eksotik yang terdiri daripada teras 4He yang terikat rapat dengan neutron tambahan yang mengorbit pada jarak yang agak jauh, membentuk halo. Usaha eksperimen terkini berjaya menjebak dan menyejukkan atom helium yang jarang dan berusia pendek ini menggunakan teknik laser, serta mengukur anjakan isotop atom sepanjang rantaian 4He-6He-8He dengan melakukan spektroskopi laser ke atas atom-atom terperangkap secara individu. Sementara itu, teori struktur atom berbilang elektron, termasuk pembetulan kerelatifan dan QED, telah mencapai tahap ketepatan yang setanding dalam pengiraan anjakan isotop. Dalam usaha selari, dengan mengukur anjakan isotop atom, jejari cas nuklear bagi isotop litium dan berilium juga telah dikaji. Teknik yang digunakan termasuk spektroskopi pengionan resonans ke atas atom litium neutral bersuhu bilik dan spektroskopi laser kolinear ke atas ion berilium. Dengan menggabungkan kemajuan dalam teori atom dan spektroskopi laser, jejari cas nuklear bagi nukleus halo ringan ini kini telah ditentukan buat kali pertama secara bebas daripada model struktur nuklear. Keputusan ini dibandingkan dengan nilai yang diramalkan oleh pelbagai pengiraan struktur nuklear, dan digunakan untuk membimbing pemahaman kita tentang daya nuklear dalam persekitaran yang sangat kaya dengan neutron.
|
ms
|
Photoproduction of $K^*$ vector mesons off nucleon is investigated within the Regge framework where the electromagnetic vertex of $\gamma K^*K^*$ fully takes into account the magnetic dipole and electric quadrupole moments of spin-1 $K^*$ vector meson. The $t$-channel $K^*(892)$, $K(494)$ and $\kappa(800)$ meson exchanges are considered for the analysis of the production mechanism. The experimentally observed rapid decrease of the cross sections for the $\gamma p \to K^{*+} \Lambda$ reaction beyond the resonance region is well reproduced by the dominance of the exchange of $K$-meson trajectory. The role of the scalar $\kappa$-meson trajectory is found to be minor in both $\gamma p$ and $\gamma n$ reactions. The cross sections for the $\gamma n \to K^{*0} \Lambda$ reaction are predicted to be about twice those of the $\gamma p \to K^{*+}\Lambda$ reaction. The role of the $K^*$ electromagnetic multipoles and the proton anomalous magnetic moment is studied through the total and differential cross sections and spin/parity asymmetries. We suggest the measurement of the photon polarization asymmetry as a tool for identifying the role of the magnetic dipole and electric quadrupole moments of the $K^*$ vector meson.
|
রেজ ফ্রেমওয়ার্কের মধ্যে $K^*$ ভেক্টর মেসনগুলির নিউক্লিয়ন থেকে ফটোউৎপাদন নিয়ে অধ্যয়ন করা হয়েছে, যেখানে $\gamma K^*K^*$ এর তড়িৎ-চৌম্বকীয় শীর্ষবিন্দু স্পিন-1 $K^*$ ভেক্টর মেসনের চৌম্বক দ্বিমেরু এবং তড়িৎ চতুর্মেরু ভ্রামকগুলি সম্পূর্ণভাবে বিবেচনায় নেয়। উৎপাদন প্রক্রিয়ার বিশ্লেষণের জন্য $t$-চ্যানেল $K^*(892)$, $K(494)$ এবং $\kappa(800)$ মেসন বিনিময়গুলি বিবেচনা করা হয়। অনুনাদ অঞ্চলের পরে $\gamma p \to K^{*+} \Lambda$ বিক্রিয়ার জন্য প্রায়োগিকভাবে পর্যবেক্ষিত অনুদৈর্ঘ্য ক্রস সেকশনের দ্রুত হ্রাস $K$-মেসন ট্র্যাজেক্টরির প্রাধান্য দ্বারা ভালোভাবে পুনরুৎপাদিত হয়। $\gamma p$ এবং $\gamma n$ উভয় বিক্রিয়াতেই স্কেলার $\kappa$-মেসন ট্র্যাজেক্টরির ভূমিকা নগণ্য পাওয়া যায়। $\gamma n \to K^{*0} \Lambda$ বিক্রিয়ার জন্য ক্রস সেকশনগুলি $\gamma p \to K^{*+}\Lambda$ বিক্রিয়ার তুলনায় প্রায় দ্বিগুণ হওয়ার পূর্বাভাস দেওয়া হয়। $K^*$ তড়িৎ-চৌম্বকীয় বহুধ্রুব এবং প্রোটনের অস্বাভাবিক চৌম্বকীয় ভ্রামকের ভূমিকা মোট ও আংশিক ক্রস সেকশন এবং স্পিন/প্যারিটি অ্যাসামেট্রির মাধ্যমে অধ্যয়ন করা হয়। $K^*$ ভেক্টর মেসনের চৌম্বক দ্বিমেরু এবং তড়িৎ চতুর্মেরু ভ্রামকগুলির ভূমিকা শনাক্ত করার সরঞ্জাম হিসাবে আমরা ফোটন সমবিন্যাস অ্যাসামেট্রি পরিমাপের প্রস্তাব করি।
|
bn
|
A critical discussion of the present status of the CERN experiments on charm dynamics and hadron collective flow is given. We emphasize the importance of the flow excitation function from 1 to 50 A$\cdot$GeV: here the hydrodynamic model has predicted the collapse of the $v_1$-flow and of the $v_2$-flow at $\sim 10$ A$\cdot$GeV; at 40 A$\cdot$GeV it has been recently observed by the NA49 collaboration. Since hadronic rescattering models predict much larger flow than observed at this energy we interpret this observation as potential evidence for a first order phase transition at high baryon density $\rho_B$. A detailed discussion of the collective flow as a barometer for the equation of state (EoS) of hot dense matter at RHIC follows. Additionally, detailed transport studies show that the away-side jet suppression can only partially ($<$ 50%) be due to hadronic rescattering. We, finally, propose upgrades and second generation experiments at RHIC which inspect the first order phase transition in the fragmentation region, i.e. at $\mu_B \approx 400$ MeV ($y \approx 4-5$), where the collapse of the proton flow should be seen in analogy to the 40 A$\cdot$GeV data. The study of Jet-Wake-riding potentials and Bow shocks -- caused by jets in the QGP formed at RHIC -- can give further information on the equation of state (EoS) and transport coefficients of the Quark Gluon Plasma (QGP).
|
Une discussion critique de l'état actuel des expériences du CERN sur la dynamique du charme et l'écoulement collectif des hadrons est présentée. Nous soulignons l'importance de la fonction d'excitation de l'écoulement entre 1 et 50 A$\cdot$GeV : ici, le modèle hydrodynamique a prédit l'effondrement de l'écoulement $v_1$ et de l'écoulement $v_2$ à $\sim 10$ A$\cdot$GeV ; cet effondrement a récemment été observé par la collaboration NA49 à 40 A$\cdot$GeV. Étant donné que les modèles de rescattering hadronique prédisent un écoulement nettement plus important que celui observé à cette énergie, nous interprétons cette observation comme une preuve potentielle d'une transition de phase du premier ordre à haute densité baryonique $\rho_B$. Une discussion détaillée de l'écoulement collectif en tant que baromètre de l'équation d'état (EoS) de la matière chaude et dense au RHIC suit. De plus, des études détaillées de transport montrent que la suppression du jet côté opposé ne peut être due qu'en partie ($<$ 50 %) au rescattering hadronique. Nous proposons enfin des améliorations et des expériences de deuxième génération au RHIC destinées à étudier la transition de phase du premier ordre dans la région de fragmentation, c'est-à-dire à $\mu_B \approx 400$ MeV ($y \approx 4-5$), où l'effondrement de l'écoulement des protons devrait être observé par analogie avec les données à 40 A$\cdot$GeV. L'étude des potentiels de type « Jet-Wake-riding » et des ondes de choc en arc (« Bow shocks ») — provoqués par les jets dans le plasma de quarks et de gluons (QGP) formé au RHIC — pourrait fournir des informations supplémentaires sur l'équation d'état (EoS) et les coefficients de transport du plasma de quarks et de gluons (QGP).
|
fr
|
We provide the first direct observations of interstellar H+ and He+ pickup ions in the solar wind from 22 AU to 38 AU. We use the Vasyliunas and Siscoe model functional form to quantify the pickup ion distributions, and while the fit parameters generally lie outside their physically expected ranges, this form allows fits that quantify variations in the pickup H+ properties with distance. By ~20 AU, the pickup ions already provide the dominant internal pressure in the solar wind. We determine the radial trends and extrapolate them to the termination shock at ~90 AU, where the pickup H+ to core solar wind density reaches ~0.14. The pickup H+ temperature and thermal pressure increase from 22-38 AU, indicating additional heating of the pickup ions. This produces very large extrapolated ratios of pickup H+ to solar wind temperature and pressure and an extrapolated ratio of the pickup ion pressure to the solar wind dynamic pressure at the termination shock of ~0.16. Such a large ratio has profound implications for moderating the termination shock and the overall outer heliospheric interaction. We also identify suprathermal tails in the H+ spectra and complex features in the He+ spectra, likely indicating variations in the pickup ion history and processing. Finally, we discover enhancements in both H+ and He+ populations just below their cutoff energies, which may be associated with enhanced local pickup. This study serves to document the release and as the citable reference of these pickup ion data for broad community use and analysis.
|
Біз 22 АҚ-дан 38 АҚ-ға дейінгі Күн желіндегі интерстелларлық H+ және He+ ұстап алатын иондардың тұңғыш ретгі тікелей бақылауларын ұсынамыз. Біз ұстап алынатын иондардың таралуын сандық бағалау үшін Ващилиунас пен Сиско моделінің функционалдық түрін қолданамыз, және әдетте сәйкестендіру параметрлері олардың физикалық тұрғыдан күтілетін диапазондарынан тыс жатса да, бұл түр ұстап алынатын H+ қасиеттерінің қашықтыққа байланысты өзгерістерін сандық бағалауға мүмкіндік береді. Шамамен 20 АҚ-да ұстап алынатын иондар Күн желінің ішкі қысымының негізгі бөлігін қамтамасыз етеді. Біз радиалдық тенденцияларды анықтап, оларды 90 АҚ шамасындағы тоқтату шокына дейін экстраполяциялаймыз, онда ұстап алынатын H+ пен негізгі Күн желінің тығыздығының қатынасы шамамен 0,14-ке жетеді. Ұстап алынатын H+ температурасы мен жылулық қысымы 22-38 АҚ аралығында өседі, бұл ұстап алынатын иондарға қосымша жылыту жүріп жатқанын көрсетеді. Бұл шокты тоқтату кезінде ұстап алынатын H+ температурасы мен қысымының Күн желісіне қатынасының өте үлкен экстраполяцияланған мәндерін және ұстап алынатын иондар қысымының Күн желінің динамикалық қысымына экстраполяцияланған қатынасының 0,16 шамасын тудырады. Мұндай үлкен қатынастың шокты тоқтатуды реттеуге және жалпы сыртқы гелиосфералық әрекеттесуге терең әсері бар. Сонымен қатар, біз H+ спектрлерінде супертермиялық құйрықтар мен He+ спектрлерінде күрделі құрылымдарды анықтадық, бұл ұстап алынатын иондардың тарихы мен өңдеуіндегі өзгерістерді көрсетуі мүмкін. Соңында, біз олардың шектік энергияларының төменінде H+ және He+ популяцияларының артуын байқадық, бұл жергілікті ұстап алу артуымен байланысты болуы мүмкін. Бұл зерттеу ұстап алынатын иондар деректерін шығару және осы деректерді кең қауымдастықтың пайдалануы мен талдауы үшін сілтеме ретінде қызмет етеді.
|
kk
|
The theory of quantum gravity is aimed to fuse general relativity with quantum theory into a more fundamental framework. The space of quantum gravity provides both the non-fixed causality of general relativity and the quantum uncertainty of quantum mechanics. In a quantum gravity scenario, the causal structure is indefinite and the processes are causally non-separable. Here, we provide a model for the information processing structure of quantum gravity. We show that the quantum gravity environment is an information resource-pool from which valuable information can be extracted. We analyze the structure of the quantum gravity space and the entanglement of the space-time geometry. We study the information transfer capabilities of quantum gravity space and define the quantum gravity channel. We reveal that the quantum gravity space acts as a background noise on the local environment states. We characterize the properties of the noise of the quantum gravity space and show that it allows the separate local parties to simulate remote outputs from the local environment state, through the process of remote simulation.
|
ทฤษฎีแรงโน้มถ่วงควอนตัมมีเป้าหมายเพื่อผสานทฤษฎีสัมพัทธภาพทั่วไปเข้ากับทฤษฎีควอนตัมให้กลายเป็นกรอบแนวคิดที่ลึกซึ้งยิ่งขึ้น พื้นที่ของแรงโน้มถ่วงควอนตัมให้ทั้งความไม่แน่นอนของเหตุและผลซึ่งพบในทฤษฎีสัมพัทธภาพทั่วไป และความไม่แน่นอนเชิงควอนตัมของกลศาสตร์ควอนตัม ในสถานการณ์ของแรงโน้มถ่วงควอนตัม โครงสร้างเชิงเหตุผลไม่ชัดเจน และกระบวนการต่างๆ ไม่สามารถแยกออกจากกันตามลำดับเหตุผลได้ ที่นี่ เราเสนอแบบจำลองสำหรับโครงสร้างการประมวลผลข้อมูลของแรงโน้มถ่วงควอนตัม เราแสดงให้เห็นว่าสภาพแวดล้อมของแรงโน้มถ่วงควอนตัมเป็นแหล่งทรัพยากรข้อมูล ที่สามารถดึงข้อมูลที่มีค่าออกมาได้ เราวิเคราะห์โครงสร้างของพื้นที่แรงโน้มถ่วงควอนตัมและการพันกันของเรขาคณิตของอวกาศ-เวลา เราศึกษาศักยภาพในการถ่ายโอนข้อมูลของพื้นที่แรงโน้มถ่วงควอนตัม และนิยามช่องทางแรงโน้มถ่วงควอนตัม เราเปิดเผยว่าพื้นที่แรงโน้มถ่วงควอนตัมทำหน้าที่เป็นสัญญาณรบกวนพื้นหลังต่อสถานะของสภาพแวดล้อมในท้องถิ่น เราอธิบายคุณสมบัติของสัญญาณรบกวนจากพื้นที่แรงโน้มถ่วงควอนตัม และแสดงให้เห็นว่าสัญญาณรบกวนนี้ทำให้หน่วยงานท้องถิ่นที่แยกจากกันสามารถจำลองผลลัพธ์จากระยะไกลจากสถานะของสภาพแวดล้อมในท้องถิ่นได้ ผ่านกระบวนการจำลองจากระยะไกล
|
th
|
CTB 109 (G109.1-1.0) is a Galactic supernova remnant (SNR) with a hemispherical shell morphology in X-rays and in the radio band. In this work we report the detection of {\gamma}-ray emission coincident with CTB 109, using 37 months of data from the Large Area Telescope on board the Fermi Gamma-ray Space Telescope. We study the broadband characteristics of the remnant using a model that includes hydrodynamics, efficient cosmic ray acceleration, nonthermal emission and a self-consistent calculation of the X-ray thermal emission. We find that the observations can be successfully fit with two distinct parameter sets, one where the {\gamma}-ray emission is produced primarily by leptons accelerated at the SNR forward shock and the other where {\gamma}-rays produced by forward shock accelerated cosmic-ray ions dominate the high-energy emission. Consideration of thermal X-ray emission introduces a novel element to the broadband fitting process, and while it does not rule out either the leptonic or the hadronic scenarios, it constrains the parameter sets required by the model to fit the observations. Moreover, the model which best fits the thermal and nonthermal emission observations is an intermediate case, where both radiation from accelerated electrons and hadrons contribute almost equally to the {\gamma}-ray flux observed.
|
CTB 109 (G109.1-1.0) рентген және радиожиіліктегі жартылай сфералық қабықша морфологиясы бар Галактиканың супернова қалдығы (СНҚ). Бұл жұмыста біз Ферми гамма-сәуле телескопының бортындағы Үлкен аймақ телескопының 37 айлық деректерін қолдана отырып, CTB 109-мен сәйкес келетін γ-сәуле шығарылуын анықтау туралы хабарлаймыз. Біз гидродинамика, ғарыштық сәулелердің тиімді үдеуі, термальды емес шығарылу және рентген термальды шығарылудың өзара байланысты есебін қамтитын модельді қолдана отырып, қалдықтың кең спектрлік сипаттамаларын зерттейміз. Біз бақылауларды екі әртүрлі параметрлер жинағымен сәтті түрде сәйкестендіруге болатынын табамыз: бірінде γ-сәуле шығарылуы негізінен СНҚ алдыңғы соққысында үдетілген лептондар арқылы туындайды, екіншісінде алдыңғы соққыда үдетілген ғарыштық сәулелер иондары жоғары энергиялы шығарылудың негізгі бөлігін құрайды. Термальды рентген шығарылуын қарастыру кең спектрлік сәйкестендіру процесіне жаңа элемент енгізеді және лептондық немесе адрондық сценарийлердің ешқайсысын жоққа шығармаса да, бақылауларды сәйкестендіру үшін модельге қажетті параметрлер жинағын шектейді. Сонымен қатар, термальды және термальды емес шығарылу бақылауларына ең жақсы сәйкес келетін модель – үдетілген электрондар мен адрондардың сәулесі γ-сәуле ағынына шамамен бірдей үлес қосатын аралық жағдай болып табылады.
|
kk
|
We present the next step in a series of papers devoted to connecting the composition of the atmospheres of forming planets with the chemistry of their natal evolving protoplanetary disks. The model presented here computes the coupled chemical and dust evolution of the disk and the formation of three planets per disk model. Our three canonical planet traps produce a Jupiter near 1 AU, a Hot Jupiter and a Super-Earth. We study the dependency of the final orbital radius, mass, and atmospheric chemistry of planets forming in disk models with initial disk masses that vary by 0.02 $M_\odot$ above and below our fiducial model ($M_{disk,0} = 0.1 ~M_\odot$). We compute C/O and C/N for the atmospheres formed in our 3 models and find that C/O$_{\rm planet}\sim$ C/O$_{\rm disk}$, which does not vary strongly between different planets formed in our model. The nitrogen content of atmospheres can vary in planets that grow in different disk models. These differences are related to the formation history of the planet, the time and location that the planet accretes its atmosphere, and are encoded in the bulk abundance of NH$_3$. These results suggest that future observations of atmospheric NH$_3$ and an estimation of the planetary C/O and C/N can inform the formation history of particular planetary systems.
|
Ipinapakita namin ang susunod na hakbang sa isang serye ng mga papel na inialay sa pag-uugnay ng komposisyon ng atmospera ng mga nabubuong planeta sa kimika ng kanilang mga paunlad na protoplanetary disk. Ang modelo na ipinakita rito ay kinakalkula ang pinagsamang kimikal at ebolusyon ng alikabok ng disk at ang pagbuo ng tatlong planeta sa bawat modelo ng disk. Ang aming tatlong karaniwang bitag na planeta ay nagbubunga ng isang Hupiter malapit sa 1 AU, isang Mainit na Hupiter, at isang Super-Earth. Pinag-aaralan namin ang pag-aalsa ng huling orbital na radyus, masa, at kimika ng atmospera ng mga planeta na nabuo sa mga modelo ng disk na may paunang masa ng disk na nag-iiba ng 0.02 $M_\odot$ pataas at paibaba sa aming pangunahing modelo ($M_{disk,0} = 0.1 ~M_\odot$). Kinakalkula namin ang C/O at C/N para sa mga atmosperang nabuo sa aming tatlong modelo at natagpuan na ang C/O$_{\rm planeta}\sim$ C/O$_{\rm disk}$, na hindi malakas na nagbabago sa pagitan ng iba't ibang planeta na nabuo sa aming modelo. Ang nilalaman ng nitrogen sa atmospera ay maaaring mag-iba sa mga planeta na lumalaki sa iba't ibang modelo ng disk. Ang mga pagkakaibang ito ay may kaugnayan sa kasaysayan ng pagbuo ng planeta, sa oras at lokasyon kung saan humuhubog ang planeta ng kanyang atmospera, at nakaimbak sa pangkalahatang abundansya ng NH$_3$. Ang mga resultang ito ay nagmumungkahi na ang hinaharap na mga obserbasyon ng atmosperikong NH$_3$ at ang pagtataya ng C/O at C/N ng planeta ay maaaring magbigay-kaalaman sa kasaysayan ng pagbuo ng partikular na mga sistemang planetaryo.
|
tl
|
As the fast growth and large integration of distributed generation, renewable energy resource, energy storage system and load response, the modern power system operation becomes much more complicated with increasing uncertainties and frequent changes. Increased operation risks are introduced to the existing commercial Energy Management System (EMS), due to its limited computational capability. In this paper, a high-performance EMS analysis framework based on the evolving graph is developed. A power grid is first modeled as an evolving graph and then the power system dynamic analysis applications, like network topology processing (NTP), state estimation (SE), power flow (PF), and contingency analysis (CA), are efficiently implemented on the system evolving graph to build a high-performance EMS analysis framework. Its computation performance is field tested using a 2749-bus power system in Sichuan, China. The results illustrate that the proposed EMS remarkably speeds up the computation performance and reaches the goal of real-time power system analysis.
|
Таратылған генерацияның, жаңартылатын энергия көздерінің, энергия сақтау жүйесінің және жүктеме жауап реакциясының тез өсуі мен үлкен интеграциясына байланысты заманауи электр жүйесінің жұмыс істеуі өсу үстіндегі анықталмаушылықтар мен жиі өзгерістермен әлдеқайда күрделі болып отыр. Шектеулі есептеу мүмкіндігіне байланысты бар коммерциялық Энергияны Басқару Жүйесіне (EMS) жұмыс істеу қауіпі арта түседі. Бұл мақалада дамып отыратын граф негізінде жоғары өнімді EMS талдау аясы әзірленді. Алдымен электр желісі дамып отыратын граф ретінде модельденеді, одан кейін желі топологиясын өңдеу (NTP), күйді бағалау (SE), қуат ағыны (PF) және жағдай талдауы (CA) сияқты электр жүйесінің динамикалық талдау қолданбалары жүйенің дамып отыратын графында тиімді түрде іске асырылып, жоғары өнімді EMS талдау аясы құрылады. Оның есептеу өнімділігі Қытайдағы Сычуанның 2749 шиналы электр жүйесінде нақты жағдайда сынақтан өткізілді. Нәтижелер ұсынылған EMS-нің есептеу өнімділігін едәуір арттыратынын және нақты уақытта электр жүйесін талдау мақсатына жететінін көрсетеді.
|
kk
|
Kundt spacetimes are of great importance in general relativity in 4 dimensions and have a number of topical applications in higher dimensions in the context of string theory. The degenerate Kundt spacetimes have many special and unique mathematical properties, including their invariant curvature structure and their holonomy structure. We provide a rigorous geometrical kinematical definition of the general Kundt spacetime in 4 dimensions; essentially a Kundt spacetime is defined as one admitting a null vector that is geodesic, expansion-free, shear-free and twist-free. A Kundt spacetime is said to be degenerate if the preferred kinematic and curvature null frames are all aligned. The degenerate Kundt spacetimes are the only spacetimes in 4 dimensions that are not $\mathcal{I}$-non-degenerate, so that they are not determined by their scalar polynomial curvature invariants. We first discuss the non-aligned Kundt spacetimes, and then turn our attention to the degenerate Kundt spacetimes. The degenerate Kundt spacetimes are classified algebraically by the Riemann tensor and its covariant derivatives in the aligned kinematic frame; as an example, we classify Riemann type D degenerate Kundt spacetimes in which $\nabla(Riem),\nabla^{(2)}(Riem)$ are also of type D. We discuss other local characteristics of the degenerate Kundt spacetimes. Finally, we discuss degenerate Kundt spacetimes in higher dimensions.
|
Gli spaziotempi di Kundt rivestono grande importanza nella relatività generale in 4 dimensioni e hanno numerose applicazioni attuali in dimensioni superiori nel contesto della teoria delle stringhe. Gli spaziotempi di Kundt degeneri possiedono molte proprietà matematiche particolari e uniche, incluse la loro struttura invariante di curvatura e la loro struttura di olonomia. Forniamo una definizione geometrica cinematica rigorosa dello spaziotempo di Kundt generale in 4 dimensioni; sostanzialmente, uno spaziotempo di Kundt è definito come uno spaziotempo che ammette un vettore nullo geodetico, privo di espansione, di taglio e di torsione. Uno spaziotempo di Kundt è detto degenere se i sistemi privilegiati cinematici e di curvatura sono tutti allineati. Gli spaziotempi di Kundt degeneri sono gli unici spaziotempi in 4 dimensioni che non sono $\mathcal{I}$-non degeneri, ovvero non sono determinati dagli invarianti polinomiali scalari di curvatura. Discutiamo innanzitutto gli spaziotempi di Kundt non allineati, per poi rivolgere l'attenzione agli spaziotempi di Kundt degeneri. Gli spaziotempi di Kundt degeneri sono classificati algebricamente dal tensore di Riemann e dalle sue derivate covarianti nel sistema cinematico allineato; come esempio, classifichiamo gli spaziotempi di Kundt degeneri di tipo Riemann D nei quali $\nabla(Riem),\nabla^{(2)}(Riem)$ sono anch'essi di tipo D. Discutiamo altre caratteristiche locali degli spaziotempi di Kundt degeneri. Infine, discutiamo gli spaziotempi di Kundt degeneri in dimensioni superiori.
|
it
|
Active eruptions from the south polar region of Saturn's small (~500 km diameter) moon Enceladus are concentrated along a series of lineaments known as the `tiger stripes', thought to be partially open fissures that connect to the liquid water ocean beneath the ice shell. Whereas aspects of the tiger stripes have been addressed in previous work, no study to date simultaneously explains why they should be located only at the south pole, why there are multiple approximately parallel and regularly spaced fractures, and what accounts for their spacing of ~35 km. Here we propose that secular cooling and the resulting ice shell thickening and global tensile stresses cause the first fracture to form at one of the poles, where the ice shell is thinnest due to tidal heating. The tensile stresses are thereby partially relieved, preventing a similar failure at the opposite pole. We propose that subsequent activity then concentrates in the vicinity of the first fracture as the steadily erupted water ice loads the flanks of the open fissure, causing bending in the surrounding elastic plate and further tensile failure in bands parallel to the first fracture, leading to a cascading sequence of parallel fissures until the conditions no longer permit through-going fractures.
|
ការផ្ទះពូថុរពីតំបន់ខាងត្បូងនៃភពរណបតូច (~500 km ប្រវែងអង្កត់ផ្ចិត) របស់សាតញ៉ា ដែលមានឈ្មោះថា អែនសែឡាដុស ត្រូវបានផ្តោតនៅតាមស៊្វីតជាច្រើន ដែលគេស្គាល់ថាជា "គ្រាប់កន្លះខែ" ដែលគេសន្មតថាជារន្ធដែលបើកចំហផ្នែកមួយ ហើយភ្ជាប់ទៅនឹងមហាសមុទ្រទឹករាវនៅក្រោមផ្ទៃទឹកកក។ ទោះបីជាមានការសិក្សាមុនៗដែលបានពិភាក្សាអំពីលក្ខណៈនៃគ្រាប់កន្លះខែក៏ដោយ ក៏គ្មានការសិក្សាណាមួយដែលពន្យល់បានពេញលេញនៅឡើយថា ហេតុអ្វីបានជាវាគ្រាន់តែមាននៅតំបន់ខាងត្បូងប៉ុណ្ណោះ ហេតុអ្វីបានជាមានរន្ធដែលស្ទើរតែស្របគ្នាជាច្រើន ហើយមានចន្លោះប្រហែល 35 km និងកត្តាអ្វីដែលបណ្តាលឱ្យមានចន្លោះនោះ។ នៅទីនេះ យើងស្នើថាការត្រជាក់បន្តបន្ទាប់ និងការកើនកម្រាស់ផ្ទៃទឹកកក និងការបង្កើតសំពាធតានតឹងទូទាំងភព បានបង្កឲ្យរន្ធដំបូងកើតឡើងនៅតំបន់មួយក្នុងចំណោមតំបន់ខាងប៉ូល ដែលផ្ទៃទឹកកកស្តើងជាងដោយសារការកកកើតកំដៅពីកំលាំងទាញទ្វេដង។ ក្នុងពេលជាមួយគ្នានោះ សំពាធតានតឹងត្រូវបានធូរចុះផ្នែកមួយ ដោយការពារការបែកបាក់ប្រភេទដូចគ្នានៅតំបន់ប៉ូលផ្ទុយវិញ។ យើងស្នើថាសកម្មភាពបន្តបន្ទាប់ទៀតនឹងផ្តោតនៅក្បែររន្ធដំបូង ដោយសារទឹកកកដែលកកឡើងវិញដោយការផ្ទះពូថុរជាបន្តបន្ទាប់ ធ្វើឲ្យផ្នែកចំហនៃរន្ធដែលបើកនៅឡើយមានការធ្វើឲ្យកោងនៅតំបន់បន្ទះដែលអាចកោងបាននៅជុំវិញ ហើយបង្កឲ្យមានការបែកបាក់តានតឹងជាជួរស្របនឹងរន្ធដំបូង ដែលនាំឲ្យកើតជារន្ធស្របជាច្រើនជាបន្តបន្ទាប់ រហូតដល់លក្ខខណ្ឌមិនអនុញ្ញាតឲ្យការបែកបាក់ឆ្លងកាត់ទៀតទេ។
|
km
|
A critical discussion of the present status of the CERN experiments on charm dynamics and hadron collective flow is given. We emphasize the importance of the flow excitation function from 1 to 50 A$\cdot$GeV: here the hydrodynamic model has predicted the collapse of the $v_1$-flow and of the $v_2$-flow at $\sim 10$ A$\cdot$GeV; at 40 A$\cdot$GeV it has been recently observed by the NA49 collaboration. Since hadronic rescattering models predict much larger flow than observed at this energy we interpret this observation as potential evidence for a first order phase transition at high baryon density $\rho_B$. A detailed discussion of the collective flow as a barometer for the equation of state (EoS) of hot dense matter at RHIC follows. Additionally, detailed transport studies show that the away-side jet suppression can only partially ($<$ 50%) be due to hadronic rescattering. We, finally, propose upgrades and second generation experiments at RHIC which inspect the first order phase transition in the fragmentation region, i.e. at $\mu_B \approx 400$ MeV ($y \approx 4-5$), where the collapse of the proton flow should be seen in analogy to the 40 A$\cdot$GeV data. The study of Jet-Wake-riding potentials and Bow shocks -- caused by jets in the QGP formed at RHIC -- can give further information on the equation of state (EoS) and transport coefficients of the Quark Gluon Plasma (QGP).
|
Приведено критическое обсуждение современного состояния экспериментов CERN по динамике очарования и коллективному потоку адронов. Подчеркивается важность функции возбуждения потока в диапазоне от 1 до 50 A·ГэВ: здесь гидродинамическая модель предсказала исчезновение v₁-потока и v₂-потока при ~10 A·ГэВ; при 40 A·ГэВ это было недавно обнаружено коллаборацией NA49. Поскольку модели перерассеяния адронов предсказывают гораздо более сильный поток, чем наблюдался при этой энергии, мы интерпретируем это наблюдение как потенциальное свидетельство первого порядка фазового перехода при высокой барионной плотности ρB. Далее следует подробное обсуждение коллективного потока как барометра уравнения состояния (УС) горячей плотной материи на RHIC. Кроме того, детальные исследования переноса показывают, что подавление струй противоположной стороны может лишь частично (<50%) объясняться адронным перерассеянием. Наконец, мы предлагаем модернизацию и эксперименты второго поколения на RHIC, которые позволят исследовать фазовый переход первого порядка в области фрагментации, т.е. при μB ≈ 400 МэВ (y ≈ 4–5), где должно наблюдаться исчезновение протонного потока, аналогичное данным при 40 A·ГэВ. Исследование потенциалов «сопровождения струи» и носовых ударных волн — вызванных струями в кварк-глюонной плазме (КГП), образующейся на RHIC — может дать дополнительную информацию об уравнении состояния (УС) и транспортных коэффициентах кварк-глюонной плазмы (КГП).
|
ru
|
We made a supplemental study of the superoutbursts and superhumps in SU UMa stars by using the recently released Kepler public data of V1504 Cyg and V344 Lyr. One of the superoutbursts in V1504 Cyg was preceded by a precursor normal outburst which was well separated from the main superoutburst. The superhump first appeared during the descending branch of the precursor normal outburst and it continued into quiescence (the deep dip between the precursor and the main superoutburst), and it began to grow in amplitude with the growth of the main superoutburst after quiescence ended. A similar phenomenon was also observed in V344 Lyr. This observation demonstrates very clearly that the superoutburst was triggered by the superhump (i.e., by the tidal instability), supporting the thermal-tidal instability model. Smak (2013, Acta Astron., 63, 109, arXiv:1301.0187) criticized our previous paper (Osaki and Kato, 2013, PASJ, 65, 50, arXiv:1212.1516) and challenged our main conclusion that various observational lines of evidence of V1504 Cyg support the thermal-tidal instability model for the superoutbursts of SU UMa stars. We present our detailed accounts to all of his criticisms by offering clear explanations. We conclude that the thermal-tidal instability model is after all only the viable model for the superoutbursts and superhumps in SU UMa stars.
|
Kami telah membuat kajian tambahan mengenai superletupan dan superjungkal dalam bintang SU UMa dengan menggunakan data awam Kepler yang baru dikeluarkan bagi V1504 Cyg dan V344 Lyr. Salah satu superletupan dalam V1504 Cyg didahului oleh satu letupan normal perintis yang jelas terpisah daripada superletupan utama. Superjungkal mula muncul semasa cabang penurunan letupan normal perintis tersebut dan berterusan ke dalam keadaan tenang (lekuk dalam antara perintis dan superletupan utama), dan ia mula meningkat amplitudnya bersama pertumbuhan superletupan utama selepas keadaan tenang berakhir. Fenomena yang serupa juga diperhatikan dalam V344 Lyr. Pemerhatian ini menunjukkan dengan jelas bahawa superletupan dicetuskan oleh superjungkal (iaitu, oleh ketidakstabilan pasang surut), menyokong model ketidakstabilan haba-pasang surut. Smak (2013, Acta Astron., 63, 109, arXiv:1301.0187) mengkritik kertas kerja kami sebelumnya (Osaki dan Kato, 2013, PASJ, 65, 50, arXiv:1212.1516) dan mencabar kesimpulan utama kami bahawa pelbagai bukti pemerhatian V1504 Cyg menyokong model ketidakstabilan haba-pasang surut bagi superletupan bintang SU UMa. Kami mengemukakan huraian terperinci terhadap semua kritikannya dengan memberikan penjelasan yang jelas. Kami membuat kesimpulan bahawa model ketidakstabilan haba-pasang surut akhirnya tetap merupakan satu-satunya model yang layak bagi superletupan dan superjungkal dalam bintang SU UMa.
|
ms
|
We investigate the Coma cluster galaxy luminosity function (GLF) at faint magnitudes, in particular in the u* band by applying photometric redshift techniques applied to deep u*, B, V, R, I images covering a region of ~1deg2 (R 24). Global and local GLFs in the B, V, R and I bands obtained with photometric redshift selection are consistent with our previous results based on a statistical background subtraction. In the area covered only by the u* image, the GLF was also derived after applying a statistical background subtraction. The GLF in the u* band shows an increase of the faint end slope towards the outer regions of the cluster (from alpha~1 in the cluster center to alpha~2 in the cluster periphery). This could be explained assuming a short burst of star formation in these galaxies when entering the cluster. The analysis of the multicolor type spatial distribution reveals that late type galaxies are distributed in clumps in the cluster outskirts, where X-ray substructures are also detected and where the GLF in the u* band is steeper.
|
Kami menyelidiki fungsi luminositas galaksi (GLF) gugus Coma pada magnitudo redup, khususnya dalam pita u*, dengan menerapkan teknik redshift fotometrik pada citra u*, B, V, R, I yang dalam yang mencakup wilayah seluas ~1 derajat persegi (R 24). GLF global dan lokal dalam pita B, V, R, dan I yang diperoleh melalui seleksi redshift fotometrik konsisten dengan hasil sebelumnya berdasarkan pengurangan latar belakang secara statistik. Di area yang hanya dicakup oleh citra u*, GLF juga diturunkan setelah menerapkan pengurangan latar belakang secara statistik. GLF dalam pita u* menunjukkan peningkatan kemiringan ujung redup ke arah wilayah luar gugus (dari alpha~1 di pusat gugus hingga alpha~2 di pinggiran gugus). Hal ini dapat dijelaskan dengan mengasumsikan ledakan singkat pembentukan bintang pada galaksi-galaksi ini saat memasuki gugus. Analisis distribusi spasial tipe berdasarkan warna majemuk mengungkapkan bahwa galaksi tipe lanjut tersebar dalam kelompok-kelompok di bagian luar gugus, di mana substruktur sinar-X juga terdeteksi dan di mana GLF dalam pita u* lebih curam.
|
id
|
Investigations of solute transport in fractured rock aquifers often rely on tracer test data acquired at a limited number of observation points. Such data do not, by themselves, allow detailed assessments of the spreading of the injected tracer plume. To better understand the transport behavior in a granitic aquifer, we combine tracer test data with single-hole ground-penetrating radar (GPR) reflection monitoring data. Five successful tracer tests were performed under various experimental conditions between two boreholes 6 m apart. For each experiment, saline tracer was injected into a previously identified packed-off transmissive fracture while repeatedly acquiring single-hole GPR reflection profiles together with electrical conductivity logs in the pumping borehole. By analyzing depth-migrated GPR difference images together with tracer breakthrough curves and associated simplified flow and transport modeling, we estimate (1) the number, the connectivity, and the geometry of fractures that contribute to tracer transport, (2) the velocity and the mass of tracer that was carried along each flow path, and (3) the effective transport parameters of the identified flow paths. We find a qualitative agreement when comparing the time evolution of GPR reflectivity strengths at strategic locations in the formation with those arising from simulated transport. The discrepancies are on the same order as those between observed and simulated breakthrough curves at the outflow locations. The rather subtle and repeatable GPR signals provide useful and complementary information to tracer test data acquired at the outflow locations and may help us to characterize transport phenomena in fractured rock aquifers.
|
شدابی چٹانوں کے تہہ خانہ آبی ذخائر میں محلول کی منتقلی کی تحقیقات اکثر محدود تعداد کے مشاہدہ نقاط سے حاصل کردہ ٹریسر ٹیسٹ کے ڈیٹا پر انحصار کرتی ہیں۔ ایسے ڈیٹا صرف اپنے آپ میں انجیکٹ کیے گئے ٹریسر کے پھیلاؤ کے مفصل جائزہ کی اجازت نہیں دیتے۔ گرینائٹ آبی ذخیرہ میں منتقلی کے رویے کو بہتر طور پر سمجھنے کے لیے، ہم ٹریسر ٹیسٹ کے ڈیٹا کو سنگل ہول گراؤنڈ پینیٹریٹنگ ریڈار (جی پی آر) ریفلیکشن مانیٹرنگ ڈیٹا کے ساتھ جوڑتے ہیں۔ دو بورہولز جو 6 میٹر کے فاصلے پر واقع ہیں، کے درمیان مختلف تجرباتی حالات میں پانچ کامیاب ٹریسر ٹیسٹ انجام دیے گئے۔ ہر تجربہ کے لیے، نمکین ٹریسر کو ایک پہلے سے شناخت شدہ پیکڈ آف ٹرانسمیسیو فریکچر میں انجیکٹ کیا گیا جبکہ پمپنگ بورہول میں بار بار سنگل ہول جی پی آر ریفلیکشن پروفائلز کے ساتھ ساتھ برقی موصلیت کے لاگ حاصل کیے گئے۔ گہرائی ہجرت شدہ جی پی آر فرق کی تصاویر کے ساتھ ساتھ ٹریسر برش تھرو کروزوں اور متعلقہ سادہ نمونہ جاتی بہاؤ اور منتقلی ماڈلنگ کے تجزیہ کے ذریعے، ہم اندازہ لگاتے ہیں: (1) وہ فریکچرز کی تعداد، ان کی منسلکیت اور ہندسہ جو ٹریسر کی منتقلی میں حصہ ڈالتے ہیں، (2) وہ رفتار اور ٹریسر کا وہ ماس جو ہر بہاؤ راستے کے ساتھ لے جایا گیا، اور (3) شناخت شدہ بہاؤ راستوں کے موثر منتقلی پیرامیٹرز۔ ہمیں تشکیل کے اہم مقامات پر جی پی آر ریفلیکٹیویٹی کی طاقت کی وقت کے ساتھ تبدیلی کا موازنہ تصور کردہ منتقلی سے حاصل ہونے والی تبدیلیوں سے کرنے پر کوالیٹیٹو مطابقت ملتی ہے۔ اختلافات ان مشاہدہ شدہ اور تصور کردہ برش تھرو کروزوں کے درمیان اختلافات کے ہم مرتبہ ہیں جو نکاسی کے مقامات پر ملتے ہیں۔ جی پی آر کے نسبتاً باریک اور دہرائے جانے والے سگنلز نکاسی کے مقامات پر حاصل کردہ ٹریسر ٹیسٹ ڈیٹا کے لیے مددگار اور مکمل کرنے والی معلومات فراہم کرتے ہیں اور ہمیں شدابی چٹانوں کے تہہ خانہ آبی ذخائر میں منتقلی کے مظاہر کی وضاحت کرنے میں مدد دے سکتے ہیں۔
|
ur
|
Large amounts of labeled training data are one of the main contributors to the great success that deep models have achieved in the past. Label acquisition for tasks other than benchmarks can pose a challenge due to requirements of both funding and expertise. By selecting unlabeled examples that are promising in terms of model improvement and only asking for respective labels, active learning can increase the efficiency of the labeling process in terms of time and cost. In this work, we describe combinations of an incremental learning scheme and methods of active learning. These allow for continuous exploration of newly observed unlabeled data. We describe selection criteria based on model uncertainty as well as expected model output change (EMOC). An object detection task is evaluated in a continuous exploration context on the PASCAL VOC dataset. We also validate a weakly supervised system based on active and incremental learning in a real-world biodiversity application where images from camera traps are analyzed. Labeling only 32 images by accepting or rejecting proposals generated by our method yields an increase in accuracy from 25.4% to 42.6%.
|
Jumlah besar data pelatihan yang telah diberi label merupakan salah satu kontributor utama atas keberhasilan besar yang dicapai oleh model-model mendalam di masa lalu. Perolehan label untuk tugas-tugas selain tolok ukur dapat menimbulkan tantangan karena memerlukan dana dan keahlian. Dengan memilih contoh tanpa label yang menjanjikan dalam hal peningkatan model dan hanya meminta label yang sesuai, pembelajaran aktif dapat meningkatkan efisiensi proses pelabelan dalam hal waktu dan biaya. Dalam karya ini, kami menjelaskan kombinasi skema pembelajaran inkremental dan metode pembelajaran aktif. Kombinasi ini memungkinkan eksplorasi berkelanjutan terhadap data tanpa label yang baru diamati. Kami menjelaskan kriteria seleksi berdasarkan ketidakpastian model serta perubahan keluaran model yang diharapkan (expected model output change/EMOC). Sebuah tugas deteksi objek dievaluasi dalam konteks eksplorasi berkelanjutan pada kumpulan data PASCAL VOC. Kami juga melakukan validasi terhadap sistem supervisi lemah berbasis pembelajaran aktif dan inkremental dalam aplikasi keanekaragaman hayati dunia nyata, di mana gambar dari perangkap kamera dianalisis. Dengan hanya melabeli 32 gambar melalui penerimaan atau penolakan terhadap usulan yang dihasilkan oleh metode kami, diperoleh peningkatan akurasi dari 25,4% menjadi 42,6%.
|
id
|
In this work we present the main atmospheric parameters, carbon, nitrogen and oxygen abundances, and 12C/13C ratios determined in a sample of 28 Galactic clump stars. Abundances of carbon were studied using the C2 band at 5086.2 {\AA}. The wavelength interval 7980-8130 {\AA} with strong CN features was analysed in order to determine nitrogen abundances and 12C/13C isotope ratios. The oxygen abundances were determined from the [O I] line at 6300 {\AA}. The mean abundances of C, N and O abundances in the investigated clump stars support our previous estimations that, compared to the Sun and dwarf stars of the Galactic disc, carbon is depleted by about 0.2 dex, nitrogen is enhanced by 0.2 dex and oxygen is close to abundances in dwarfs. The 12C/13C and C/N ratios for galactic red clump stars analysed were compared to the evolutionary models of extra-mixing. The steeper drop of 12C/13C ratio in the model of thermohaline mixing by Charbonnel & Lagarde better reflects the observational data at low stellar masses than the more shallow model of cool bottom processing by Boothroyd & Sackmann. For stars of about 2 Msun masses a modelling of rotationally induced mixing should be considered with rotation of about 250 km s-1 at the time when a star was at the hydrogen-core-burning stage.
|
Dans ce travail, nous présentons les principaux paramètres atmosphériques, les abondances de carbone, d'azote et d'oxygène, ainsi que les rapports 12C/13C déterminés pour un échantillon de 28 étoiles géantes rouges du groupe à hélium dégénéré. Les abondances en carbone ont été étudiées à l'aide de la bande du C2 située à 5086,2 {\AA}. L'intervalle de longueur d'onde 7980-8130 {\AA}, contenant des raies CN intenses, a été analysé afin de déterminer les abondances en azote et les rapports isotopiques 12C/13C. Les abondances en oxygène ont été déterminées à partir de la raie [O I] située à 6300 {\AA}. Les abondances moyennes en C, N et O des étoiles du groupe à hélium étudiées confirment nos estimations antérieures selon lesquelles, comparé au Soleil et aux étoiles naines du disque galactique, le carbone est appauvri d'environ 0,2 dex, l'azote est enrichi d'environ 0,2 dex, tandis que l'oxygène présente des abondances proches de celles des naines. Les rapports 12C/13C et C/N des étoiles rouges du groupe à hélium analysées ont été comparés à des modèles évolutifs incluant un mélange supplémentaire. La chute plus prononcée du rapport 12C/13C dans le modèle de mélange thermohaline de Charbonnel & Lagarde reflète mieux les données observationnelles à faible masse stellaire que le modèle moins prononcé du traitement de fond froid de Boothroyd & Sackmann. Pour des étoiles d'environ 2 masses solaires, un modèle incluant un mélange induit par la rotation devrait être envisagé, avec une rotation d'environ 250 km s-1 au moment où l'étoile se trouvait à la phase de combustion centrale de l'hydrogène.
|
fr
|
Superfluidity and superconductivity are remarkable manifestations of quantum coherence at a macroscopic scale. The dynamics of superfluids has dominated the study of these systems for decades now, but a comprehensive theoretical framework is still lacking. We introduce a local extension of the time-dependent density functional theory to describe the dynamics of fermionic superfluids. Within this approach one can correctly represent vortex quantization, generation, and dynamics, the transition from a superfluid to a normal phase and a number of other large amplitude collective modes which are beyond the scope of two-fluid hydrodynamics, Ginzburg-Landau and/or Gross-Pitaevskii approaches. We illustrate the power of this approach by studying the generation of quantized vortices, vortex rings, vortex reconnection, and transition from a superfluid to a normal state in real time for a unitary Fermi gas. We predict the emergence of a new qualitative phenomenon in superfluid dynamics of gases, the existence of stable superfluidity when the systems are stirred with velocities significantly exceeding the nominal Landau critical velocity in these systems.
|
Süperakışkanlık ve süperiletkenlik, makroskobik ölçekte kuantum uyumunun dikkat çekici biçimleridir. Süperakışkanların dinamikleri, bu sistemlerin incelenmesinde uzun yıllardır ön planda yer almıştır ancak hâlâ kapsamlı bir teorik çerçeve eksikliğini sürdürmektedir. Fermiyonik süperakışkanların dinamiklerini tanımlamak için zamana bağlı yoğunluk fonksiyonel teorisinin yerel bir genişletmesini sunuyoruz. Bu yaklaşım içinde, iki akışkanlı hidrodinamik, Ginzburg-Landau ve/veya Gross-Pitaevskii yaklaşımlarının kapsamı dışında kalan, vorteks kuantalanması, oluşumu ve dinamiği, süperakışkan fazdan normal faza geçiş ve bir dizi büyük genlikli kolektif kip doğru bir şekilde temsil edilebilir. Birimsel bir Fermi gazı için kuantalanmış vortekslerin, vorteks halkalarının, vorteks yeniden birleşiminin ve süperakışkan durumdan normal duruma geçişin gerçek zamanlı olarak oluşumunu inceleyerek bu yaklaşımın gücünü gösteriyoruz. Sistemlerin bu sistemlerdeki adi Landau kritik hızından önemli ölçüde daha yüksek hızlarda karıştırıldığında, kararlı süperakışkanlığın varlığı gibi süperakışkan gaz dinamiğinde yeni nitelikte bir fenomenin ortaya çıkacağını öngörüyoruz.
|
tr
|
We propose to develop a high-energy heavy-ion experimental database and make it accessible to the scientific community through an on-line interace. This database will be searchable and cross-indexed with relevant publications, including published detector descriptions. Since this database will be a community resource, it requires the high-energy nuclear physics community's financial and manpower support. This database should eventually contain all published data from the Bevalac, AGS and SPS to RHIC and LHC energies, proton-proton to nucleus-nucleus collisions as well as other relevant systems and all measured observables. Such a database would have tremendous scientific payoff as it makes systematic studies easier and allows simpler benchmarking of theoretical models to a broad range of old and new experiments. Furthermore, there is a growing need for compilations of high-energy nuclear data for applications including stockpile stewardship, technology development for intertial confinement fusion and target and source development for upcoming facilities such as the Next Linear Collider. To enhance the utility of this database, we propose periodically performing evaluations of the data and summarizing the results in topical reviews.
|
Yüksek enerjili ağır iyon deneysel bir veri tabanı geliştirilmesini öneriyor ve bu veri tabanına bilimsel topluluk tarafından çevrimiçi arayüz üzerinden erişilebilir hale getirilmesini planlıyoruz. Bu veri tabanı, ilgili yayınlarla, yayımlanmış dedektör tanımlarını da içermek üzere, aranabilir ve çapraz indekslenebilir olacak. Bu veri tabanı bir topluluk kaynağı olacağından, yüksek enerji nükleer fiziği topluluğunun maddi ve insan gücü desteği gerekmektedir. Bu veri tabanı nihayetinde Bevalac, AGS ve SPS'den RHIC ve LHC enerjilerine, proton-proton'dan çekirdek-çekirdek çarpışmalarına kadar ve diğer ilgili sistemlere ve tüm ölçülen gözlemlenebilir niceliklere ait tüm yayımlanmış verileri içermelidir. Böyle bir veri tabanı, sistematik araştırmaları kolaylaştırarak ve eski ile yeni deneylerin geniş bir yelpazesine karşı teorik modellerin daha kolay karşılaştırılmasını sağlayarak büyük bilimsel kazanımlar sağlayacaktır. Ayrıca, stok birikimi yönetiminden, eylemsizlik kaplamalı füzyon teknolojisi geliştirme ve Yaklaşan Doğrusal Çarpıştırıcı gibi gelecekteki tesisler için hedef ve kaynak geliştirme uygulamalarına kadar yüksek enerjili nükleer verilerin derlenmesine duyulan ihtiyaç giderek artmaktadır. Bu veri tabanının yararlılığını artırmak amacıyla, verilerin periyodik olarak değerlendirilmesini ve sonuçların konuya özel incelemeler şeklinde özetlenmesini öneriyoruz.
|
tr
|
We derive mass functions (MF) for halo red dwarfs (the faintest hydrogen burning stars) and then extrapolate to place limits on the total mass of halo brown dwarfs (stars not quite massive enough to burn hydrogen). The mass functions are obtained from the luminosity function of a sample of 114 local halo stars in the USNO parallax survey (Dahn \etal 1995). We use stellar models of Alexander \etal (1996) and make varying assumptions about metallicity and about possible unresolved binaries in the sample. We find that the MF for halo red dwarfs cannot rise more quickly than $1/m^2$ as one approaches the hydrogen burning limit. Using recent results from star formation theory, we extrapolate the MF into the brown-dwarf regime. We see that likely extrapolations imply that the total mass of brown dwarfs in the halo is less than $\sim 3\%$ of the local mass density of the halo ($\sim 0.3\%$ for the more realistic models we consider). Our limits apply to brown dwarfs in the halo that come from the same stellar population as the red dwarfs.
|
Мы определяем функции массы (ФМ) для гало красных карликов (самых слабых звезд, в которых происходит термоядерное горение водорода), а затем экстраполируем их, чтобы установить пределы общей массы коричневых карликов гало (звезд, недостаточно массивных для горения водорода). Функции массы получены из функции светимости выборки из 114 близких звезд гало в обзоре параллаксов USNO (Dahn и др., 1995). Мы использовали модели звезд Александера и др. (1996) и делали различные предположения относительно металличности и возможного наличия неразрешённых двойных систем в выборке. Мы обнаружили, что ФМ для гало красных карликов не может возрастать быстрее, чем $1/m^2$, по мере приближения к пределу горения водорода. Используя недавние результаты теории звездообразования, мы экстраполировали ФМ в область коричневых карликов. Мы видим, что вероятные экстраполяции указывают на то, что общая масса коричневых карликов в гало составляет менее $\sim 3\%$ от локальной плотности массы гало ($\sim 0.3\%$ для более реалистичных моделей, которые мы рассматриваем). Наши ограничения применимы к коричневым карликам в гало, происходящим из той же звёздной популяции, что и красные карлики.
|
ru
|
With the aim of better understanding the class of 4D theories generated by compactifications of 6D superconformal field theories (SCFTs), we study the structure of N = 1 supersymmetric punctures for class S_Gamma theories, namely the 6D SCFTs obtained from M5-branes probing an ADE singularity. For M5-branes probing a C^2 / Z_k singularity, the punctures are governed by a dynamical system in which evolution in time corresponds to motion to a neighboring node in an affine A-type quiver. Classification of punctures reduces to determining consistent initial conditions which produce periodic orbits. The study of this system is particularly tractable in the case of a single M5-brane. Even in this "simple" case, the solutions exhibit a remarkable level of complexity: Only specific rational values for the initial momenta lead to periodic orbits, and small perturbations in these values lead to vastly different late time behavior. Another difference from half BPS punctures of class S theories includes the appearance of a continuous complex "zero mode" modulus in some puncture solutions. The construction of punctures with higher order poles involves a related set of recursion relations. The resulting structures also generalize to systems with multiple M5-branes as well as probes of D- and E-type orbifold singularities.
|
Với mục đích hiểu rõ hơn về lớp các lý thuyết 4D phát sinh từ việc rút gọn chiều không gian của các lý thuyết trường siêu đối xứng (SCFTs) 6 chiều, chúng tôi nghiên cứu cấu trúc của các điểm thủng siêu đối xứng N = 1 trong các lý thuyết lớp S_Gamma, cụ thể là các SCFTs 6D thu được từ các brane M5 dò vào một điểm kỳ dị ADE. Đối với các brane M5 dò vào điểm kỳ dị C^2 / Z_k, các điểm thủng được chi phối bởi một hệ động lực học, trong đó sự tiến triển theo thời gian tương ứng với chuyển động sang một nút liền kề trong một mô hình dây chuyền affine kiểu A. Việc phân loại các điểm thủng được đưa về việc xác định các điều kiện ban đầu nhất quán sinh ra các quỹ đạo tuần hoàn. Việc nghiên cứu hệ thống này đặc biệt khả thi trong trường hợp một brane M5 đơn lẻ. Ngay cả trong trường hợp "đơn giản" này, các nghiệm vẫn thể hiện mức độ phức tạp đáng chú ý: chỉ những giá trị hữu tỉ cụ thể của động lượng ban đầu mới dẫn đến các quỹ đạo tuần hoàn, và những nhiễu loạn nhỏ trong các giá trị này lại dẫn đến hành vi rất khác biệt ở thời gian dài. Một điểm khác biệt khác so với các điểm thủng nửa BPS trong các lý thuyết lớp S là sự xuất hiện của một modul liên tục phức "mode zero" trong một số nghiệm điểm thủng. Việc xây dựng các điểm thủng có cực bậc cao hơn liên quan đến một tập hợp các hệ thức truy hồi tương ứng. Các cấu trúc thu được cũng được tổng quát hóa cho các hệ nhiều brane M5 cũng như các brane dò vào các điểm kỳ dị dạng D và E.
|
vi
|
Wide-band radio polarization observations offer the possibility to recover information about the magnetic fields in synchrotron sources, such as details of their three-dimensional configuration, that has previously been inaccessible. The key physical process involved is the Faraday rotation of the polarized emission in the source (and elsewhere along the wave's propagation path to the observer). In order to proceed, reliable methods are required for inverting the signals observed in wavelength space into useful data in Faraday space, with robust estimates of their uncertainty. In this paper, we examine how variations of the intrinsic angle of polarized emission $\psi_{0}$ with the Faraday depth $\phi$ within a source affect the observable quantities. Using simple models for the Faraday dispersion $F(\phi)$ and $\psi_{0}(\phi)$, along with the current and planned properties of the main radio interferometers, we demonstrate how degeneracies among the parameters describing the magneto-ionic medium can be minimised by combining observations in different wavebands. We also discuss how depolarization by Faraday dispersion due to a random component of the magnetic field attenuates the variations in the spectral energy distribution of the polarization and shifts its peak towards shorter wavelengths. This additional effect reduces the prospect of recovering the characteristics of the magnetic field helicity in magneto-ionic media dominated by the turbulent component of the magnetic field.
|
広帯域の電波偏光観測は、シンクロトロン放射源内の磁場、特にこれまでアクセスできなかったその三次元的構造に関する情報を回復する可能性を提供する。関係する主要な物理過程は、放射源内部（および観測者までの波の伝播経路の他の場所）における偏光放射のファラデー回転である。この研究を進めるためには、波長空間で観測された信号をファラデー空間における有用なデータに、その不確かさを確実に評価しながら逆変換する信頼できる手法が必要となる。本論文では、放射源内部において、偏光放射の固有角ψ₀がファラデーの深さφとともに変化する場合に、それが観測量にどのような影響を与えるかを検討する。ファラデー分散F(φ)およびψ₀(φ)の単純なモデルを用い、主要な電波干渉計の現在および将来の性能特性を組み合わせることで、磁気イオン媒体を記述するパラメータ間の縮退を、異なる波長帯の観測を統合することでどのように最小限に抑えることができるかを示す。また、磁場のランダム成分によるファラデー分散による減偏光が、偏光のスペクトルエネルギー分布における変動を減衰させ、そのピークをより短い波長側へシフトさせることについても議論する。この追加的な効果により、磁場の乱流成分が支配的な磁気イオン媒体における磁場のヘリシティ特性を回復する可能性が低下する。
|
ja
|
Information on the spectral shape of prompt emission in gamma-ray bursts (GRB) is mostly available only at energies $\gtrsim10$ keV, where the main instruments for GRB detection are sensitive. The origin of this emission is still very uncertain because of the apparent inconsistency with synchrotron radiation, which is the most obvious candidate, and the resulting need for considering less straightforward scenarios. The inclusion of data down to soft X-rays ($\sim$ 0.5 keV), which are available only in a small fraction of GRBs, has firmly established the common presence of a spectral break in the low-energy part of prompt spectra, and the consistency of the overall spectral shape with synchrotron radiation in the moderately fast-cooling regime, the low-energy break being identified with the cooling frequency. In this work we further extend the range of investigation down to the optical band. In particular, we test the synchrotron interpretation by directly fitting a theoretically derived synchrotron spectrum and making use of optical to gamma-ray data. Secondly, we test an alternative model that considers the presence of a black-body component at $\sim$keV energies, in addition to a non-thermal component that is responsible for the emission at the spectral peak (100 keV-1 MeV). We find that synchrotron radiation provides a good description of the broadband data, while models composed of a thermal and a non-thermal component require the introduction of a low-energy break in the non-thermal component in order to be consistent with optical observations. Motivated by the good quality of the synchrotron fits, we explore the physical parameter space of the emitting region. In a basic prompt emission scenario we find quite contrived solutions for the magnetic field strength (5 G $<B^\prime<40$ G) and for the location of the region where the radiation is produced ($R_\gamma>10^{16}$ cm).
|
Гамма-сәулелердің жарқылдарындағы (ГСЖ) тез сәулеленудің спектрлік пішіні туралы ақпарат негізінен тек ГСЖ-ді анықтау үшін негізгі құралдар сезімтал болатын $\gtrsim10$ кэВ энергияларында ғана қолжетімді. Бұл сәулеленудің шығу тегі әлі де өте анық емес, себебі ең ықтимал келетін синхротронды сәулеленумен көрінетін қайшылық бар, сондықтан күрделірек сценарийлерді қарастыру қажеттігі туындайды. Тек аз ғана ГСЖ-да ғана қолжетімді болатын жұмсақ рентген сәулелеріне дейінгі ($\sim$ 0,5 кэВ) деректерді қосу арқылы тез сәулелену спектрлерінің төменгі энергиялық бөлігінде спектрлік сынудың жалпы түрде бар екендігі анық белгіленді және жалпы спектрлік пішіннің орташа жылдам салқындайтын режимдегі синхротронды сәулеленумен сәйкестігі, мұнда төменгі энергиялық сынуды салқындау жиілігімен теңестірді. Бұл жұмыста біз зерттеу диапазонын оптикалық диапазонға дейін кеңейтеміз. Нақтырақ айтқанда, біз теориялық түрде алынған синхротронды спектрді тікелей сәйкестендіру арқылы және оптикалық сәулелерден гамма-сәулелерге дейінгі деректерді пайдалану арқылы синхротрондық түсіндіруді тексереміз. Екіншіден, біз спектрлік шыңдағы (100 кэВ-1 МэВ) сәулеленудің жауапкершілігін атқаратын термиялық емес компонентке қосымша $\sim$кэВ энергияларында қара дене компонентінің болуын қарастыратын альтернативті модельді тексереміз. Біз синхротронды сәулелену кең спектрлік диапазондағы деректерді жақсы сипаттайтынын, ал термиялық және термиялық емес компоненттерден тұратын модельдер оптикалық бақылаулармен сәйкес болу үшін термиялық емес компонентте төменгі энергиялық сынуды енгізуі қажет екендігін таптық. Синхротрондық сәйкестендірудің жақсы сапасына негізделе отырып, біз сәулелендіруші аймақтың физикалық параметрлер кеңістігін зерттейміз. Негізгі тез сәулелену сценарийінде магнит өрісінің күші (5 Г $<B^\prime<40$ Г) және сәулелену шығатын аймақтың орналасуы ($R_\gamma>10^{16}$ см) үшін өте күрделі шешімдер табылды.
|
kk
|
Kundt spacetimes are of great importance in general relativity in 4 dimensions and have a number of topical applications in higher dimensions in the context of string theory. The degenerate Kundt spacetimes have many special and unique mathematical properties, including their invariant curvature structure and their holonomy structure. We provide a rigorous geometrical kinematical definition of the general Kundt spacetime in 4 dimensions; essentially a Kundt spacetime is defined as one admitting a null vector that is geodesic, expansion-free, shear-free and twist-free. A Kundt spacetime is said to be degenerate if the preferred kinematic and curvature null frames are all aligned. The degenerate Kundt spacetimes are the only spacetimes in 4 dimensions that are not $\mathcal{I}$-non-degenerate, so that they are not determined by their scalar polynomial curvature invariants. We first discuss the non-aligned Kundt spacetimes, and then turn our attention to the degenerate Kundt spacetimes. The degenerate Kundt spacetimes are classified algebraically by the Riemann tensor and its covariant derivatives in the aligned kinematic frame; as an example, we classify Riemann type D degenerate Kundt spacetimes in which $\nabla(Riem),\nabla^{(2)}(Riem)$ are also of type D. We discuss other local characteristics of the degenerate Kundt spacetimes. Finally, we discuss degenerate Kundt spacetimes in higher dimensions.
|
쿤트 시공간은 4차원 일반 상대성이론에서 매우 중요한 역할을 하며, 끈 이론의 맥락에서 고차원으로의 여러 주요 응용 사례를 지닌다. 퇴화된 쿤트 시공간은 곡률 구조 및 홀로노미 구조와 같은 많은 특별하고 독특한 수학적 성질을 갖는다. 우리는 4차원에서 일반적인 쿤트 시공간에 대한 엄밀한 기하학적 운동학적 정의를 제시하는데, 본질적으로 쿤트 시공간이란 측지선적이며 팽창이 없고 전단이 없으며 비틀림이 없는 영벡터를 허용하는 시공간으로 정의된다. 쿤트 시공간이 퇴화되었다고 할 때는 선호되는 운동학적 기저와 곡률 기저가 모두 정렬되어 있음을 의미한다. 퇴화된 쿤트 시공간은 4차원에서 유일하게 $\mathcal{I}$-비퇴화적이지 않은 시공간이며, 따라서 스칼라 다항식 곡률 불변량들에 의해 결정되지 않는다. 먼저 정렬되지 않은 쿤트 시공간에 대해 논의한 후, 퇴화된 쿤트 시공간으로 관심을 돌린다. 퇴화된 쿤트 시공간은 정렬된 운동학적 기저에서 리만 텐서와 그 공변 도함수들을 기준으로 대수적으로 분류된다. 예를 들어, $\nabla(Riem)$과 $\nabla^{(2)}(Riem)$ 또한 유형 D인 리만 유형 D의 퇴화된 쿤트 시공간을 분류한다. 또한 퇴화된 쿤트 시공간의 다른 국소적 특성들에 대해 논의한다. 마지막으로 고차원에서의 퇴화된 쿤트 시공간에 대해 논의한다.
|
ko
|
Superfluidity and superconductivity are remarkable manifestations of quantum coherence at a macroscopic scale. The dynamics of superfluids has dominated the study of these systems for decades now, but a comprehensive theoretical framework is still lacking. We introduce a local extension of the time-dependent density functional theory to describe the dynamics of fermionic superfluids. Within this approach one can correctly represent vortex quantization, generation, and dynamics, the transition from a superfluid to a normal phase and a number of other large amplitude collective modes which are beyond the scope of two-fluid hydrodynamics, Ginzburg-Landau and/or Gross-Pitaevskii approaches. We illustrate the power of this approach by studying the generation of quantized vortices, vortex rings, vortex reconnection, and transition from a superfluid to a normal state in real time for a unitary Fermi gas. We predict the emergence of a new qualitative phenomenon in superfluid dynamics of gases, the existence of stable superfluidity when the systems are stirred with velocities significantly exceeding the nominal Landau critical velocity in these systems.
|
超流動性と超伝導性は、マクロなスケールにおける量子コヒーレンスの顕著な現れである。超流動体のダイナミクスは、数十年にわたりこれらの系の研究を支配してきたが、いまだ包括的な理論的枠組みは確立されていない。本研究では、フェルミ型超流動体のダイナミクスを記述するための、時間依存密度汎関数理論の局所的拡張を導入する。このアプローチにより、渦の量子化、生成およびダイナミクス、超流動相から通常相への転移、ならびに二流体流体力学、ギンツブルク・ランダウおよび/またはグロス・ピタエフスキーアプローチの範囲外にある多数の大きな振幅の集団励起モードを、正確に表現することができる。本アプローチの有効性を、単位系フェルミガスにおける量子化された渦、渦輪、渦の再結合、および超流動状態から通常状態への遷移のリアルタイムでの解析によって示す。さらに、これらの系において、名目上のランダウ臨界速度を大きく上回る速度で系を攪拌した場合に、安定した超流動性が存在するという、気体の超流動ダイナミクスにおける新たな定性的現象の出現を予測する。
|
ja
|
Automatic image colourisation is the computer vision research path that studies how to colourise greyscale images (for restoration). Deep learning techniques improved image colourisation yielding astonishing results. These differ by various factors, such as structural differences, input types, user assistance, etc. Most of them, base the architectural structure on convolutional layers with no emphasis on layers specialised in object features extraction. We introduce a novel downsampling upsampling architecture named TUCaN (Tiny UCapsNet) that exploits the collaboration of convolutional layers and capsule layers to obtain a neat colourisation of entities present in every single image. This is obtained by enforcing collaboration among such layers by skip and residual connections. We pose the problem as a per pixel colour classification task that identifies colours as a bin in a quantized space. To train the network, in contrast with the standard end to end learning method, we propose the progressive learning scheme to extract the context of objects by only manipulating the learning process without changing the model. In this scheme, the upsampling starts from the reconstruction of low resolution images and progressively grows to high resolution images throughout the training phase. Experimental results on three benchmark datasets show that our approach with ImageNet10k dataset outperforms existing methods on standard quality metrics and achieves state of the art performances on image colourisation. We performed a user study to quantify the perceptual realism of the colourisation results demonstrating: that progressive learning let the TUCaN achieve better colours than the end to end scheme; and pointing out the limitations of the existing evaluation metrics.
|
ការពណ៌នារូបភាពដោយស្វ័យប្រវត្តិគឺជាផ្លូវស្រាវជ្រាវនៃការមើលឃើញរបស់កុំព្យូទ័រ ដែលសិក្សាអំពីរបៀបពណ៌នារូបភាពពណ៌ស្រាល (សម្រាប់ការស្តារឡើងវិញ)។ បច្ចេកទេសរៀនជ្រៅបានកែលម្អការពណ៌នារូបភាព ដោយផ្តល់លទ្ធផលដ៏អស្ចារ្យ។ វាផ្សេងគ្នាដោយកត្តាផ្សេងៗ ដូចជាភាពខុសគ្នានៃរចនាសម្ព័ន្ធ ប្រភេទបញ្ចូល ការជួយពីអ្នកប្រើប្រាស់ ជាដើម។ ភាគច្រើន ពួកវាស្ថិតនៅលើរចនាសម្ព័ន្ធរចនាសម្ព័ន្ធដែលផ្អែកលើស្រទាប់បង្ហាប់ ដោយគ្មានការផ្តោតលើស្រទាប់ដែលឯកទេសក្នុងការទាញយកលក្ខណៈវត្ថុ។ យើងបានណែនាំអំពីរចនាសម្ព័ន្ធថ្មីមួយដែលមានឈ្មោះថា TUCaN (Tiny UCapsNet) ដែលប្រើប្រាស់ការសហការរវាងស្រទាប់បង្ហាប់ និងស្រទាប់កាបសូល ដើម្បីទទួលបានការពណ៌នាដ៏ស្អាតនៃវត្ថុដែលមាននៅក្នុងរូបភាពនីមួយៗ។ នេះត្រូវបានទទួលបានដោយការបង្កើនការសហការរវាងស្រទាប់ទាំងនោះតាមរយៈការតភ្ជាប់លែង និងការតភ្ជាប់ដែលនៅសល់។ យើងដាក់បញ្ហានេះជាការងារចាត់ថ្នាក់ពណ៌ក្នុងមួយភីចសែល ដែលកំណត់ពណ៌ជាប្រអប់មួយក្នុងលំហដែលបានបំបែក។ ដើម្បីបណ្តុះបណ្តាលបណ្តាញ ផ្ទុយពីវិធីសាកសួរចុងក្រោយទៅចុងក្រោយស្តង់ដារ យើងស្នើគម្រោងរៀនជាសាច់ដុំ ដើម្បីទាញយកបរិបទរបស់វត្ថុដោយគ្រាន់តែគ្រប់គ្រងដំណើរការរៀន ដោយមិនផ្លាស់ប្តូរគំរូ។ នៅក្នុងគម្រោងនេះ ការពង្រីកចាប់ផ្តើមពីការស្តាររូបភាពដែលមានកម្រិតប្រសើរទាប ហើយកើនឡើងទៅរូបភាពដែលមានកម្រិតប្រសើរខ្ពស់ជាបន្តបន្ទាប់ក្នុងអំឡុងពេលបណ្តុះបណ្តាល។ លទ្ធផលពិសោធន៍លើឯកសារយោងបីបង្ហាញថា វិធីសាកសួររបស់យើងជាមួយឯកសារយោង ImageNet10k ល្អជាងវិធីសាកសួរដែលមានស្រាប់ លើម៉ែត្រគុណភាពស្តង់ដារ ហើយទទួលបានលទ្ធផលកំពូលបំផុតក្នុងការពណ៌នារូបភាព។ យើងបានធ្វើការសិក្សាលើអ្នកប្រើប្រាស់ដើម្បីវាស់វែងភាពជាក់ស្តែងដែលអាចយល់បាននៃលទ្ធផលពណ៌នា ដែលបង្ហាញថា៖ ការរៀនជាសាច់ដុំអនុញ្ញាតឱ្យ TUCaN ទទួលបានពណ៌ល្អជាងគំរូចុងក្រោយទៅចុងក្រោយ។ ហើយបញ្ជាក់ពីដែនកំណត់នៃម៉ែត្រវាយតម្លៃដែលមានស្រាប់។
|
km
|
In 2016 we carried out a Swift monitoring program to track the X-ray hardness variability of eight type-I AGN over a year. The purpose of this monitoring was to find intense obscuration events in AGN, and thereby study them by triggering joint XMM-Newton, NuSTAR, and HST observations. We successfully accomplished this for NGC 3783 in December 2016. We found heavy X-ray absorption produced by an obscuring outflow in this AGN. As a result of this obscuration, interesting absorption features appear in the UV and X-ray spectra, which are not present in the previous epochs. Namely, the obscuration produces broad and blue-shifted UV absorption lines of Ly$\alpha$, C IV, and N V, together with a new high-ionisation component producing Fe XXV and Fe XXVI absorption lines. In soft X-rays, only narrow emission lines stand out above the diminished continuum as they are not absorbed by the obscurer. Our analysis shows that the obscurer partially covers the central source with a column density of few $10^{23}$ cm$^{-2}$, outflowing with a velocity of few thousand km s$^{-1}$. The obscuration in NGC 3783 is variable and lasts for about a month. Unlike the commonly-seen warm-absorber winds at pc-scale distances from the black hole, the eclipsing wind in NGC 3783 is located at about 10 light days. Our results suggest the obscuration is produced by an inhomogeneous and clumpy medium, consistent with clouds in the base of a radiatively-driven disk wind at the outer broad-line region of the AGN.
|
ในปี 2016 เราได้ดำเนินโครงการติดตามสังเกตการณ์ด้วยกล้อง Swift เพื่อวัดความแปรผันของความเข้มรังสีเอกซ์ของ AGN ชนิดที่หนึ่งจำนวนแปดดวงเป็นระยะเวลาหนึ่งปี วัตถุประสงค์ของการติดตามสังเกตการณ์นี้คือเพื่อค้นหาเหตุการณ์การบดบังที่รุนแรงใน AGN และศึกษาเหตุการณ์เหล่านั้นโดยการเริ่มต้นการสังเกตการณ์ร่วมกันด้วยกล้อง XMM-Newton, NuSTAR และ HST เราประสบความสำเร็จในการทำเช่นนี้กับ NGC 3783 ในเดือนธันวาคม 2016 โดยเราพบการดูดกลืนรังสีเอกซ์อย่างรุนแรงที่เกิดจากกระแสไหลออกที่ทำหน้าที่บดบังใน AGN ดวงนี้ ผลจากการบดบังนี้ ทำให้เกิดลักษณะการดูดกลืนที่น่าสนใจในสเปกตรัมช่วงอัลตราไวโอเลตและรังสีเอกซ์ ซึ่งไม่ปรากฏในช่วงเวลาก่อนหน้า โดยเฉพาะอย่างยิ่ง การบดบังนี้ทำให้เกิดเส้นดูดกลืนอัลตราไวโอเลตที่มีความกว้างและเลื่อนออกไปทางสีน้ำเงินของ Ly$\alpha$, C IV และ N V ร่วมกับองค์ประกอบใหม่ที่มีไอออไนเซชันสูง ซึ่งสร้างเส้นดูดกลืนของ Fe XXV และ Fe XXVI ในช่วงรังสีเอกซ์อ่อน มีเพียงเส้นปลดปล่อยที่แคบเท่านั้นที่เด่นชัดเหนือสเปกตรัมต่อเนื่องที่ลดลง เนื่องจากเส้นเหล่านี้ไม่ถูกดูดกลืนโดยตัวบดบัง การวิเคราะห์ของเราแสดงให้เห็นว่าตัวบดบังปิดบังแหล่งกำเนิดตรงกลางเพียงบางส่วน โดยมีความหนาแน่นของคอลัมน์ประมาณ $10^{23}$ ต่อตารางเซนติเมตร และไหลออกไปด้วยความเร็วหลายพันกิโลเมตรต่อวินาที การบดบังใน NGC 3783 มีการเปลี่ยนแปลงและคงอยู่ประมาณหนึ่งเดือน ต่างจากกระแสลมดูดกลืนอุ่นที่พบทั่วไป ซึ่งอยู่ห่างจากหลุมดำเป็นระยะทางมาตราส่วนพาร์เซค กระแสลมที่มาบดบังใน NGC 3783 ตั้งอยู่ที่ระยะประมาณ 10 วันแสง ผลการศึกษาของเราชี้ให้เห็นว่าการบดบังนี้เกิดจากตัวกลางที่ไม่สม่ำเสมอและเป็นก้อน ซึ่งสอดคล้องกับกลุ่มเมฆที่อยู่ที่ฐานของกระแสลมจากแผ่นดิสก์ที่ถูกขับเคลื่อนด้วยรังสี ซึ่งตั้งอยู่ที่บริเวณนอกสุดของบริเวณปล่อยเส้นกว้างของ AGN
|
th
|
The neutron-rich 6He and 8He isotopes exhibit an exotic nuclear structure that consists of a tightly bound 4He-like core with additional neutrons orbiting at a relatively large distance, forming a halo. Recent experimental efforts have succeeded in laser trapping and cooling these short-lived, rare helium atoms, and have measured the atomic isotope shifts along the 4He-6He-8He chain by performing laser spectroscopy on individual trapped atoms. Meanwhile, the few-electron atomic structure theory, including relativistic and QED corrections, has reached a comparable degree of accuracy in the calculation of the isotope shifts. In parallel efforts, also by measuring atomic isotope shifts, the nuclear charge radii of lithium and beryllium isotopes have been studied. The techniques employed were resonance ionization spectroscopy on neutral, thermal lithium atoms and collinear laser spectroscopy on beryllium ions. Combining advances in both atomic theory and laser spectroscopy, the charge radii of these light halo nuclei have now been determined for the first time independent of nuclear structure models. The results are compared with the values predicted by a number of nuclear structure calculations, and are used to guide our understanding of the nuclear forces in the extremely neutron-rich environment.
|
Isotop 6He dan 8He yang kaya neutron menunjukkan struktur inti eksotis yang terdiri dari inti terikat kuat mirip 4He dengan neutron tambahan yang mengorbit pada jarak yang relatif jauh, membentuk halo. Upaya eksperimental terkini berhasil menjebak dan mendinginkan atom helium langka yang berumur pendek ini menggunakan laser, serta mengukur pergeseran isotop atomik sepanjang rantai 4He-6He-8He dengan melakukan spektroskopi laser pada atom-atom terperangkap tunggal. Di sisi lain, teori struktur atom ber-elektron sedikit, termasuk koreksi relativistik dan QED, telah mencapai tingkat akurasi yang sebanding dalam perhitungan pergeseran isotop. Dalam upaya paralel, dengan cara mengukur pergeseran isotop atomik, jari-jari muatan inti isotop litium dan berilium juga telah diteliti. Teknik yang digunakan adalah spektroskopi ionisasi resonansi pada atom litium netral bersuhu ruang dan spektroskopi laser kolinear pada ion berilium. Dengan menggabungkan kemajuan dalam teori atom dan spektroskopi laser, jari-jari muatan inti halo ringan ini kini telah ditentukan untuk pertama kalinya tanpa bergantung pada model struktur inti. Hasil tersebut dibandingkan dengan nilai-nilai yang diprediksi oleh sejumlah perhitungan struktur inti, serta digunakan untuk membimbing pemahaman kita mengenai gaya-gaya inti dalam lingkungan yang sangat kaya neutron.
|
id
|
Biological processes involve a variety of spatial and temporal scales. A holistic understanding of many biological processes therefore requires multi-scale models which capture the relevant properties on all these scales. In this manuscript we review mathematical modelling approaches used to describe the individual spatial scales and how they are integrated into holistic models. We discuss the relation between spatial and temporal scales and the implication of that on multi-scale modelling. Based upon this overview over state-of-the-art modelling approaches, we formulate key challenges in mathematical and computational modelling of biological multi-scale and multi-physics processes. In particular, we considered the availability of analysis tools for multi-scale models and model-based multi-scale data integration. We provide a compact review of methods for model-based data integration and model-based hypothesis testing. Furthermore, novel approaches and recent trends are discussed, including computation time reduction using reduced order and surrogate models, which contribute to the solution of inference problems. We conclude the manuscript by providing a few ideas for the development of tailored multi-scale inference methods.
|
ဇီဝလုပ်ငန်းစဉ်များတွင် အာကာသနှင့် အချိန်ပိုင်းဆိုင်ရာ အဆင့်အတန်းများစွာ ပါဝင်ပါသည်။ ထို့ကြောင့် ဇီဝလုပ်ငန်းစဉ်များစွာကို စနစ်တကျနားလည်ရန်အတွက် ဤအဆင့်အတန်းများအားလုံးရှိ သက်ဆိုင်ရာ ဂုဏ်သတ္တိများကို ဖမ်းယူထားသော အဆင့်အတန်းစုံ မော်ဒယ်များ လိုအပ်ပါသည်။ ဤစာတမ်းတွင် တစ်ဦးချင်း အာကာသအဆင့်အတန်းများကို ဖော်ပြရန်အတွက် အသုံးပြုသော သင်္ချာမော်ဒယ်ဖော်ဆောင်မှု ချဉ်းကပ်မှုများနှင့် စနစ်တကျမော်ဒယ်များအဖြစ် ပေါင်းစပ်ခြင်းနည်းလမ်းများကို ပြန်လည်သုံးသပ်ပါသည်။ အာကာသနှင့် အချိန်ပိုင်းဆိုင်ရာ အဆင့်အတန်းများ၏ ဆက်နွယ်မှုနှင့် ထိုအဆင့်အတန်းစုံ မော်ဒယ်ဖော်ဆောင်မှုအပေါ် သက်ရောက်မှုကို ဆွေးနွေးပါသည်။ ခေတ်မီမော်ဒယ်ဖော်ဆောင်မှု ချဉ်းကပ်မှုများ၏ ဤအကြည့်အမြင်ပေါ်တွင် အခြေခံ၍ ဇီဝဆိုင်ရာ အဆင့်အတန်းစုံနှင့် ရူပဗေဒအဆင့်အတန်းစုံ လုပ်ငန်းစဉ်များအတွက် သင်္ချာနှင့် ကွန်ပျူတာမော်ဒယ်ဖော်ဆောင်မှုဆိုင်ရာ အဓိက စိန်ခေါ်မှုများကို သတ်မှတ်ပါသည်။ အထူးသဖြင့် အဆင့်အတန်းစုံမော်ဒယ်များအတွက် ခွဲခြမ်းစိတ်ဖြာမှုကိရိယာများ ရရှိမှုနှင့် မော်ဒယ်အခြေပြု အဆင့်အတန်းစုံဒေတာပေါင်းစပ်မှုကို စဉ်းစားပါသည်။ ထပ်မံ၍ မော်ဒယ်အခြေပြုဒေတာပေါင်းစပ်မှုနှင့် မော်ဒယ်အခြေပြု သုတေသနအယူအဆစမ်းသပ်မှုအတွက် နည်းလမ်းများကို ကွက်တိုင်းသုံးသပ်ပေးပါသည်။ ထို့အပြင် လျှော့ချထားသော အဆင့်နှင့် အစားထိုးမော်ဒယ်များကို အသုံးပြု၍ တွက်ချက်မှုအချိန်ကို လျှော့ချခြင်းကဲ့သို့သော ခေတ်ပေါ်ချဉ်းကပ်မှုများနှင့် အိမ်ရှင်းလင်းချက်ပြဿနာများကို ဖြေရှင်းရာတွင် ပံ့ပိုးပေးသော မကြာသေးမီက လားရာများကို ဆွေးနွေးပါသည်။ အဆင့်အတန်းစုံ အိမ်ရှင်းလင်းချက်နည်းလမ်းများကို ရည်ရွယ်၍ ဖွံ့ဖြိုးတိုးတက်စေရန် အကြံပြုချက်အချို့ကို ဤစာတမ်းကို အဆုံးသတ်ရာတွင် ပေးအပ်ပါသည်။
|
my
|
We made a supplemental study of the superoutbursts and superhumps in SU UMa stars by using the recently released Kepler public data of V1504 Cyg and V344 Lyr. One of the superoutbursts in V1504 Cyg was preceded by a precursor normal outburst which was well separated from the main superoutburst. The superhump first appeared during the descending branch of the precursor normal outburst and it continued into quiescence (the deep dip between the precursor and the main superoutburst), and it began to grow in amplitude with the growth of the main superoutburst after quiescence ended. A similar phenomenon was also observed in V344 Lyr. This observation demonstrates very clearly that the superoutburst was triggered by the superhump (i.e., by the tidal instability), supporting the thermal-tidal instability model. Smak (2013, Acta Astron., 63, 109, arXiv:1301.0187) criticized our previous paper (Osaki and Kato, 2013, PASJ, 65, 50, arXiv:1212.1516) and challenged our main conclusion that various observational lines of evidence of V1504 Cyg support the thermal-tidal instability model for the superoutbursts of SU UMa stars. We present our detailed accounts to all of his criticisms by offering clear explanations. We conclude that the thermal-tidal instability model is after all only the viable model for the superoutbursts and superhumps in SU UMa stars.
|
Son zamanlarda yayınlanan V1504 Cyg ve V344 Lyr'nin Kepler halka açık verilerini kullanarak SU UMa yıldızlarındaki süperpatlamalar ve süperhump'lar üzerine tamamlayıcı bir çalışma yaptık. V1504 Cyg'deki süperpatlamalardan biri, ana süperpatlamadan açıkça ayrılmış olan bir ön normal patlamayla başlamıştır. Süperhump, ön normal patlamanın azalma evresi sırasında ortaya çıkmış ve sessizlik dönemine (ön patlama ile ana süperpatlama arasındaki derin çukur) kadar devam etmiştir ve sessizlik döneminin ardından ana süperpatlamanın büyümesiyle birlikte genliğinde artmaya başlamıştır. Benzer bir olay V344 Lyr'de de gözlemlenmiştir. Bu gözlem, süperpatlamanın süperhump (yani gelgit kararsızlığı) tarafından tetiklendiğini çok açık bir şekilde göstermekte olup termal-gelgit kararsızlığı modelini desteklemektedir. Smak (2013, Acta Astron., 63, 109, arXiv:1301.0187), daha önceki makalemizi (Osaki ve Kato, 2013, PASJ, 65, 50, arXiv:1212.1516) eleştirerek V1504 Cyg'nin çeşitli gözlemsel kanıtlarının SU UMa yıldızlarının süperpatlamaları için termal-gelgit kararsızlığı modelini desteklediğine dair ana sonucumuzu sorgulamıştır. Onun tüm eleştirilerine açıklayıcı açıklamalar sunarak ayrıntılı yanıtlarımızı sunuyoruz. Sonuç olarak, SU UMa yıldızlarındaki süperpatlamalar ve süperhump'lar için termal-gelgit kararsızlığı modelinin yine de geçerli tek model olduğu sonucuna varıyoruz.
|
tr
|
General relativity can be formulated equivalently with a non-Riemannian geometry that associates with an affine connection of nonzero nonmetricity $Q$ but vanishing curvature $R$ and torsion $T$. Modification based on this description of gravity generates the $f(Q)$ gravity. In this work we explore the application of $f(Q)$ gravity to the spherically symmetric configurations. We discuss the gauge fixing and connections in this setting. We demonstrate the effects of $f(Q)$ by considering the external and internal solutions of compact stars. The external background solutions for any regular form of $f(Q)$ coincide with the corresponding solutions in general relativity, i.e., the Schwarzschild-de Sitter solution and the Reissner-Nordstr\"om-de Sitter solution with an electromagnetic field. For internal structure, with a simple model $f(Q)=Q+\alpha Q^2$ and a polytropic equation of state, we find that a negative modification ($\alpha<0$) provides support to more stellar masses while a positive one ($\alpha>0$) reduces the amount of matter of the star.
|
Maaaring iharap ang pangkalahatang relatibidad nang may katumbas na di-Riemannian heometriya na nag-uugnay sa isang affine connection na may di-serong nonmetricity $Q$ ngunit may papalitang curvature $R$ at torsion $T$. Ang pagbabago na nakabatay sa ganitong deskripsyon ng grabidad ay nagbubunga ng $f(Q)$ na grabidad. Sa gawaing ito, tatalakayin natin ang aplikasyon ng $f(Q)$ na grabidad sa mga spherically symmetric na konpigurasyon. Pag-uusapan natin ang gauge fixing at mga koneksyon sa ganitong kalagayan. Ipapakita natin ang mga epekto ng $f(Q)$ sa pamamagitan ng pagsusuri sa mga panlabas at panloob na solusyon ng mga kompakto ng bituin. Ang mga panlabas na solusyon ng likod-bahay para sa anumang regular na anyo ng $f(Q)$ ay magkatugma sa mga koresponding solusyon sa pangkalahatang relatibidad, i.e., ang solusyon ng Schwarzschild-de Sitter at ang solusyon ng Reissner-Nordstr\"om-de Sitter na may electromagnetic field. Para sa panloob na istruktura, gamit ang simpleng modelo na $f(Q)=Q+\alpha Q^2$ at isang polytropic na equation of state, natagpuan nating ang negatibong pagbabago ($\alpha<0$) ay nagbibigay-suporta sa mas maraming masa ng bituin samantalang ang positibong pagbabago ($\alpha>0$) ay nagpapababa sa dami ng materya ng bituin.
|
tl
|
Kundt spacetimes are of great importance in general relativity in 4 dimensions and have a number of topical applications in higher dimensions in the context of string theory. The degenerate Kundt spacetimes have many special and unique mathematical properties, including their invariant curvature structure and their holonomy structure. We provide a rigorous geometrical kinematical definition of the general Kundt spacetime in 4 dimensions; essentially a Kundt spacetime is defined as one admitting a null vector that is geodesic, expansion-free, shear-free and twist-free. A Kundt spacetime is said to be degenerate if the preferred kinematic and curvature null frames are all aligned. The degenerate Kundt spacetimes are the only spacetimes in 4 dimensions that are not $\mathcal{I}$-non-degenerate, so that they are not determined by their scalar polynomial curvature invariants. We first discuss the non-aligned Kundt spacetimes, and then turn our attention to the degenerate Kundt spacetimes. The degenerate Kundt spacetimes are classified algebraically by the Riemann tensor and its covariant derivatives in the aligned kinematic frame; as an example, we classify Riemann type D degenerate Kundt spacetimes in which $\nabla(Riem),\nabla^{(2)}(Riem)$ are also of type D. We discuss other local characteristics of the degenerate Kundt spacetimes. Finally, we discuss degenerate Kundt spacetimes in higher dimensions.
|
Ruang-waktu Kundt memiliki peranan penting dalam relativitas umum dalam 4 dimensi dan memiliki sejumlah aplikasi aktual dalam dimensi lebih tinggi dalam konteks teori string. Ruang-waktu Kundt terdegenerasi memiliki banyak sifat matematis khusus dan unik, termasuk struktur kelengkungan invarian dan struktur holonominya. Kami memberikan definisi kinematik geometris yang ketat terhadap ruang-waktu Kundt umum dalam 4 dimensi; secara esensial, ruang-waktu Kundt didefinisikan sebagai ruang-waktu yang memuat vektor nol yang geodesik, bebas ekspansi, bebas geser, dan bebas puntiran. Suatu ruang-waktu Kundt dikatakan terdegenerasi jika kerangka nol kinematik dan kelengkungan yang dipilih semuanya sejajar. Ruang-waktu Kundt terdegenerasi merupakan satu-satunya ruang-waktu dalam 4 dimensi yang tidak $\mathcal{I}$-non-degenerasi, sehingga tidak ditentukan oleh invarian skalar polinomial kelengkungannya. Kami terlebih dahulu membahas ruang-waktu Kundt yang tidak sejajar, kemudian mengalihkan perhatian pada ruang-waktu Kundt terdegenerasi. Ruang-waktu Kundt terdegenerasi diklasifikasikan secara aljabar berdasarkan tensor Riemann dan turunan kovariannya dalam kerangka kinematik yang sejajar; sebagai contoh, kami mengklasifikasikan ruang-waktu Kundt terdegenerasi tipe D menurut Riemann di mana $\nabla(Riem),\nabla^{(2)}(Riem)$ juga bertipe D. Kami membahas karakteristik lokal lain dari ruang-waktu Kundt terdegenerasi. Terakhir, kami membahas ruang-waktu Kundt terdegenerasi dalam dimensi lebih tinggi.
|
id
|
In this paper, we provide non-parametric statistical tools to test stationarity of microstructure noise in general hidden Ito semimartingales, and discuss how to measure liquidity risk using high frequency financial data. In particular, we investigate the impact of non-stationary microstructure noise on some volatility estimators, and design three complementary tests by exploiting edge effects, information aggregation of local estimates and high-frequency asymptotic approximation. The asymptotic distributions of these tests are available under both stationary and non-stationary assumptions, thereby enable us to conservatively control type-I errors and meanwhile ensure the proposed tests enjoy the asymptotically optimal statistical power. Besides it also enables us to empirically measure aggregate liquidity risks by these test statistics. As byproducts, functional dependence and endogenous microstructure noise are briefly discussed. Simulation with a realistic configuration corroborates our theoretical results, and our empirical study indicates the prevalence of non-stationary microstructure noise in New York Stock Exchange.
|
Dalam kertas ini, kami menyediakan alat statistik bukan parametrik untuk menguji kestasionaran hingar mikrostruktur dalam semimartingal Ito tersembunyi secara umum, serta membincangkan cara mengukur risiko kecairan menggunakan data kewangan frekuensi tinggi. Secara khusus, kami mengkaji kesan hingar mikrostruktur bukan stasioner terhadap sesetengah penganggar volatiliti, dan mereka bentuk tiga ujian pelengkap dengan memanfaatkan kesan pinggir, pengagregatan maklumat daripada anggaran setempat, dan penghampiran asimptot frekuensi tinggi. Taburan asimptot bagi ujian-ujian ini tersedia di bawah kedua-dua andaian stasioner dan bukan stasioner, membolehkan kita mengawal ralat jenis-I secara konservatif dan serentak memastikan ujian yang dicadangkan memiliki kuasa statistik optimum secara asimptot. Selain itu, ia juga membolehkan kita mengukur secara empirikal risiko kecairan agregat menggunakan statistik ujian ini. Sebagai hasil sampingan, pergantungan fungsian dan hingar mikrostruktur endogen dibincangkan secara ringkas. Simulasi dengan konfigurasi yang realistik mengesahkan keputusan teori kami, dan kajian empirikal kami menunjukkan bahawa hingar mikrostruktur bukan stasioner lazim berlaku di Bursa Saham New York.
|
ms
|
The neutron-rich 6He and 8He isotopes exhibit an exotic nuclear structure that consists of a tightly bound 4He-like core with additional neutrons orbiting at a relatively large distance, forming a halo. Recent experimental efforts have succeeded in laser trapping and cooling these short-lived, rare helium atoms, and have measured the atomic isotope shifts along the 4He-6He-8He chain by performing laser spectroscopy on individual trapped atoms. Meanwhile, the few-electron atomic structure theory, including relativistic and QED corrections, has reached a comparable degree of accuracy in the calculation of the isotope shifts. In parallel efforts, also by measuring atomic isotope shifts, the nuclear charge radii of lithium and beryllium isotopes have been studied. The techniques employed were resonance ionization spectroscopy on neutral, thermal lithium atoms and collinear laser spectroscopy on beryllium ions. Combining advances in both atomic theory and laser spectroscopy, the charge radii of these light halo nuclei have now been determined for the first time independent of nuclear structure models. The results are compared with the values predicted by a number of nuclear structure calculations, and are used to guide our understanding of the nuclear forces in the extremely neutron-rich environment.
|
Gli isotopi ricchi di neutroni 6He e 8He presentano una struttura nucleare esotica costituita da un nucleo strettamente legato simile al 4He, con neutroni aggiuntivi che orbitano a una distanza relativamente grande, formando un alone. Recenti sforzi sperimentali sono riusciti a intrappolare e raffreddare con laser questi atomi di elio rari e a vita breve, misurando gli spostamenti isotopici atomici lungo la catena 4He-6He-8He mediante spettroscopia laser su singoli atomi intrappolati. Nel frattempo, la teoria della struttura atomica a pochi elettroni, inclusi gli effetti relativistici e le correzioni QED, ha raggiunto un grado di accuratezza comparabile nei calcoli degli spostamenti isotopici. Parallelamente, attraverso la misura degli spostamenti isotopici atomici, sono stati studiati i raggi di carica nucleare degli isotopi del litio e del berillio. Le tecniche impiegate sono state la spettroscopia di ionizzazione per risonanza su atomi neutri di litio termici e la spettroscopia laser collineare su ioni di berillio. Combinando i progressi nella teoria atomica e nella spettroscopia laser, i raggi di carica di questi nuclei leggeri con alone sono stati ora determinati per la prima volta in modo indipendente dai modelli di struttura nucleare. I risultati sono confrontati con i valori predetti da numerose calcoli di struttura nucleare e vengono utilizzati per guidare la nostra comprensione delle forze nucleari in ambienti estremamente ricchi di neutroni.
|
it
|
We use state-of-the-art radiation-MHD simulations and 3D non-LTE radiative transfer computations to investigate \Halpha\ line formation in the solar chromosphere and apply the results of this investigation to develop the potential of \Halpha\ as diagnostic of the chromosphere. We show that one can accurately model \Halpha\ line formation assuming statistical equilibrium and complete frequency redistribution provided the computation of the model atmosphere included non-equilibrium ionization of hydrogen, and the Lyman-$\alpha$ and Lyman-$\beta$ line profiles are described by Doppler profiles. We find that 3D radiative transfer is essential in modeling hydrogen lines due to the low photon destruction probability in \Halpha. The \Halpha\ opacity in the upper chromosphere is mainly sensitive to the mass density and only weakly sensitive to temperature. We find that the \Halpha\ line-core intensity is correlated with the average formation height: the larger the average formation height, the lower the intensity. The line-core width is a measure of the gas temperature in the line-forming region. The fibril-like dark structures seen in \Halpha\ line-core images computed from our model atmosphere are tracing magnetic field lines. These structures are caused by field-aligned ridges of enhanced chromospheric mass density that raise their average formation height, and therefore makes them appear dark against their deeper-formed surroundings. We compare with observations, and find that the simulated line-core widths are very similar to the observed ones, without the need for additional microturbulence.
|
ကျွန်ုပ်တို့သည် နေ၏ ခရိုမိုစ်ဖီးယားရှိ Hα မျဉ်းဖွဲ့စည်းမှုကို စူးစမ်းလေ့လာရန်နှင့် ခရိုမိုစ်ဖီးယား၏ ရောဂါရှာဖွေမှုတွင် Hα ၏ အလားအလာကို ဖွံ့ဖြိုးတိုးတက်ရန် ဤလေ့လာမှု၏ ရလဒ်များကို အသုံးချရန် ခေတ်မီ ရေဒီယေးရှင်-MHD စီမံကိန်းများနှင့် 3D non-LTE ရေဒီယေးရှင် လွှဲပြောင်းမှု တွက်ချက်မှုများကို အသုံးပြုသည်။ ဟိုက်ဒရိုဂျင်၏ မဟာခြားနားသော အယ်လ်ဂျီဘရာ အယ်လ်ဂျီဘရာ ဖြစ်စဉ်ကို မော်ဒယ်လော့ဂ်များတွင် ထည့်သွင်းတွက်ချက်ပြီး Lyman-α နှင့် Lyman-β မျဉ်းများ၏ ပရိုဖိုင်းများကို Doppler ပရိုဖိုင်းများဖြင့် ဖော်ပြပါက စံချိန်စံညွှန်း အပြိုင်အဆိုင် အခြေအနေနှင့် အပြည့်အဝ ကြိမ်နှုန်း ပြန်လည်ဖြန့်ဝေမှုကို ယူဆ၍ Hα မျဉ်းဖွဲ့စည်းမှုကို တိကျစွာ မော်ဒယ်လုပ်နိုင်ကြောင်း ကျွန်ုပ်တို့ပြသသည်။ Hα တွင် ဖိတ်ခေါ်မှု ဖျက်စီးမှု အလွန်နည်းပါးခြင်းကြောင့် ဟိုက်ဒရိုဂျင် မျဉ်းများကို မော်ဒယ်လုပ်ရာတွင် 3D ရေဒီယေးရှင် လွှဲပြောင်းမှုသည် အလွန်အရေးကြီးကြောင်း ကျွန်ုပ်တို့တွေ့ရှိရသည်။ ခရိုမိုစ်ဖီးယား၏ အပေါ်ပိုင်းတွင် Hα အမှောင်ခိုမှုသည် အဓိကအားဖြင့် အမှုန်သိပ်သည်းဆပေါ်တွင် အာရုံစိုက်ပြီး အပူချိန်ပေါ်တွင် အာရုံငယ်စွာသာ ရှိသည်။ Hα မျဉ်း၏ ဗဟိုအလင်းသည် ပျမ်းမျှ ဖွဲ့စည်းမှုအမြင့်နှင့် ဆက်စပ်နေသည်။ ပျမ်းမျှ ဖွဲ့စည်းမှုအမြင့် များလေလေ၊ အလင်းအားနည်းလေလေဖြစ်သည်။ မျဉ်းဗဟို၏ ကျယ်လောင်မှုသည် မျဉ်းဖွဲ့စည်းရာဇဝင်ရှိ ဓာတ်ငွေ့၏ အပူချိန်ကို တိုင်းတာမှုတစ်ခုဖြစ်သည်။ ကျွန်ုပ်တို့၏ မော်ဒယ်လော့ဂ်များမှ တွက်ချက်ထားသော Hα မျဉ်းဗဟို ပုံများတွင် မြင်ရသော ကြိုးကဲ့သို့ မှောင်သော ဖွဲ့စည်းပုံများသည် သံလိုက်စက်ကွင်း လိုင်းများကို ခြေရာခံနေကြောင်း ကျွန်ုပ်တို့တွေ့ရှိရသည်။ ဤဖွဲ့စည်းပုံများသည် ခရိုမိုစ်ဖီးယား၏ များပြားသော အမှုန်သိပ်သည်းမှုကို ဖြစ်ပေါ်စေသော စက်ကွင်းနှင့် တစ်လျှောက်ရှိ ထွက်ပေါ်နေသော မြေပြင်များကြောင့် ဖြစ်ပြီး ၎င်းတို့၏ ပျမ်းမျှ ဖွဲ့စည်းမှုအမြင့်ကို မြှင့်တင်ပေးကာ ထို့ကြောင့် ၎င်းတို့၏ နက်ရှိုင်းစွာဖွဲ့စည်းထားသော ဝန်းကျင်များနှင့် နှိုင်းယှဉ်ပါက မှောင်နေစေသည်။ ကျွန်ုပ်တို့သည် စူးစမ်းလေ့လာမှုများနှင့် နှိုင်းယှဉ်ကာ မော်ဒယ်လုပ်ထားသော မျဉ်းဗဟို ကျယ်လောင်မှုများသည် စူးစမ်းလေ့လာမှုများနှင့် အလွန်ဆင်တူကြောင်း တွေ့ရှိရပြီး အပို microturbulence မလိုအပ်ပါ။
|
my
|
A recent publication provides the network graph for a neocortical microcircuit comprising 8 million connections between 31,000 neurons (H. Markram, et al., Reconstruction and simulation of neocortical microcircuitry, Cell, 163 (2015) no. 2, 456-492). Since traditional graph-theoretical methods may not be sufficient to understand the immense complexity of such a biological network, we explored whether methods from algebraic topology could provide a new perspective on its structural and functional organization. Structural topological analysis revealed that directed graphs representing connectivity among neurons in the microcircuit deviated significantly from different varieties of randomized graph. In particular, the directed graphs contained in the order of $10^7$ simplices {\DH} groups of neurons with all-to-all directed connectivity. Some of these simplices contained up to 8 neurons, making them the most extreme neuronal clustering motif ever reported. Functional topological analysis of simulated neuronal activity in the microcircuit revealed novel spatio-temporal metrics that provide an effective classification of functional responses to qualitatively different stimuli. This study represents the first algebraic topological analysis of structural connectomics and connectomics-based spatio-temporal activity in a biologically realistic neural microcircuit. The methods used in the study show promise for more general applications in network science.
|
최근 한 출판물은 31,000개의 뉴런 사이의 8백만 개 연결로 구성된 신피질 미세회로에 대한 네트워크 그래프를 제공한다(H. Markram 외, Reconstruction and simulation of neocortical microcircuitry, Cell, 163(2015) 2호, 456-492). 이러한 생물학적 네트워크의 엄청난 복잡성을 이해하기 위해 전통적인 그래프 이론적 방법이 충분하지 않을 수 있으므로, 대수적 위상수학의 방법들이 그 구조적 및 기능적 조직에 대한 새로운 관점을 제공할 수 있는지 탐구하였다. 구조적 위상 분석 결과, 미세회로 내 뉴런들 간의 연결을 나타내는 방향성 그래프는 다양한 형태의 무작위화된 그래프들과 상당히 벗어나 있음을 보여주었다. 특히, 해당 방향성 그래프는 전방향 연결을 갖는 뉴런 집단인 심플렉스(simplex)를 약 10^7개 포함하고 있었다. 이러한 심플렉스 중 일부는 최대 8개의 뉴런을 포함하여 지금까지 보고된 뉴런 클러스터링 모티프 중 가장 극단적인 사례였다. 미세회로 내 시뮬레이션된 뉴런 활동에 대한 기능적 위상 분석은 질적으로 다른 자극에 대한 기능적 반응을 효과적으로 분류할 수 있는 새로운 공간-시간적 척도를 밝혀냈다. 본 연구는 생물학적으로 현실적인 신경 미세회로에서 구조적 연결체 및 연결체 기반 공간-시간적 활동에 대한 최초의 대수적 위상 분석 사례이다. 본 연구에서 사용된 방법들은 네트워크 과학 전반에 걸쳐 보다 일반적인 적용 가능성을 보여준다.
|
ko
|
Distances on symbolic musical sequences are needed for a variety of applications, from music retrieval to automatic music generation. These musical sequences belong to a given corpus (or style) and it is obvious that a good distance on musical sequences should take this information into account; being able to define a distance ex nihilo which could be applicable to all music styles seems implausible. A distance could also be invariant under some transformations, such as transpositions, so that it can be used as a distance between musical motives rather than musical sequences. However, to our knowledge, none of the approaches to devise musical distances seem to address these issues. This paper introduces a method to build transposition-invariant distances on symbolic musical sequences which are learned from data. It is a hybrid distance which combines learned feature representations of musical sequences with a handcrafted rank distance. This distance depends less on the musical encoding of the data than previous methods and gives perceptually good results. We demonstrate its efficiency on the dataset of chorale melodies by J.S. Bach.
|
သီချင်းရှာဖွေခြင်းမှ အလိုအလျောက် ဂီတထုတ်လုပ်ခြင်းအထိ အသုံးပြုမှုအမျိုးမျိုးအတွက် သင်္ကေတဆိုင်ရာ ဂီတအစီအစဥ်များပေါ်တွင် အကွာအဝေးများ လိုအပ်ပါသည်။ ဤသို့သော ဂီတအစီအစဥ်များသည် ပေးထားသော စာစု (သို့) စတိုင်တစ်ခုတွင် ပါဝင်ပြီး ဂီတအစီအစဥ်များတွင် ကောင်းမွန်သော အကွာအဝေးတစ်ခုသည် ဤအချက်အလက်များကို ထည့်သွင်းစဉ်းစားသင့်သည်ဟု သိသာထင်ရှားပါသည်။ ဂီတစတိုင်အားလုံးကို အသုံးပြုနိုင်မည့် အကွာအဝေးကို ex nihilo ဖြင့် သတ်မှတ်နိုင်ခြင်းသည် မဖြစ်နိုင်လောက်အောင် ရှုပ်ထွေးပါသည်။ အကွာအဝေးတစ်ခုသည် တိုးမြှင့်မှုကဲ့သို့သော အပြောင်းအလဲများအောက်တွင် မပြောင်းလဲနိုင်သော ဂုဏ်သတ္တိရှိနိုင်ပြီး ဂီတအစီအစဥ်များထက် ဂီတဆိုင်ရာ စိတ်ကူးများကြားတွင် အကွာအဝေးတစ်ခုအဖြစ် အသုံးပြုနိုင်ပါသည်။ သို့သော် ကျွန်ုပ်တို့ သိရသမျှအရ ဂီတအကွာအဝေးများကို ဖန်တီးရန် ချဉ်းကပ်မှုများသည် ဤပြဿနာများကို ဖြေရှင်းရန် မကြိုးပမ်းကြပါ။ ဤစာတမ်းတွင် ဒေတာမှ သင်ယူထားသော တိုးမြှင့်မှုများအောက်တွင် မပြောင်းလဲနိုင်သော အကွာအဝေးများကို သင်္ကေတဆိုင်ရာ ဂီတအစီအစဥ်များပေါ်တွင် တည်ဆောက်ရန် နည်းလမ်းတစ်ခုကို မိတ်ဆက်ပေးထားပါသည်။ ဤအကွာအဝေးသည် ဂီတအစီအစဥ်များ၏ သင်ယူထားသော အင်္ဂါရပ်များကို လက်နှင့်ဖန်တီးထားသော အဆင့်အတန်းအကွာအဝေးနှင့် ပေါင်းစပ်ထားသော ရောနှောအကွာအဝေးတစ်ခုဖြစ်ပါသည်။ ဤအကွာအဝေးသည် ယခင်နည်းလမ်းများကဲ့သို့ ဒေတာ၏ ဂီတအက္ခရာသင်္ကေတပေါ်တွင် မူတည်မှု နည်းပါးပြီး အာရုံခံမှုအရ ကောင်းမွန်သော ရလဒ်များကို ပေးစွမ်းနိုင်ပါသည်။ J.S. Bach ၏ ချောရယ်သီချင်းများ၏ ဒေတာစုပေါ်တွင် ဤနည်းလမ်း၏ ထိရောက်မှုကို ကျွန်ုပ်တို့ ပြသထားပါသည်။
|
my
|
Historically the training of teams has been implemented using a face-to-face approach. In the past decade, on-line multiuser virtual environments have offered a solution for training teams whose members are geographically dispersed. In order to develop on effective team training activity, a high sense of presence among the participant needs to be reached. Previous research studies reported being able to reach a high level of presence even when using inexpensive technology such as laptop and headset. This study evaluates the level of presence of ten subjects who have to perform a team-building activity in a multi-user virtual environment using a laptop computer and a headset. The authors are interested in determining which user characterizes, such as gender, age and knowledge of computers, have a strong correlation with the level of sense of presence. The results of this study showed that female participants were more likely to engage in the activity and perceived fewer negative effects. Participants who reported less negative effects such as feeling tired, dizzy, or experiencing eye strain during the team-building activity reached a higher level of sense of presence.
|
Исторически сложилось так, что подготовка команд осуществлялась с применением очного подхода. В прошлом десятилетии онлайновые многопользовательские виртуальные среды предложили решение для обучения команд, члены которых географически удалены друг от друга. Для разработки эффективной деятельности по подготовке команд необходимо достичь высокого уровня присутствия среди участников. Предыдущие исследования сообщали о возможности достижения высокого уровня присутствия даже при использовании недорогих технологий, таких как ноутбук и гарнитура. В данном исследовании оценивается уровень присутствия десяти испытуемых, которым необходимо выполнить командообразующую деятельность в многопользовательской виртуальной среде с использованием ноутбука и гарнитуры. Авторов интересует, какие характеристики пользователя, такие как пол, возраст и уровень владения компьютером, имеют сильную корреляцию с уровнем ощущения присутствия. Результаты данного исследования показали, что женщины с большей вероятностью включались в деятельность и испытывали меньшее количество негативных эффектов. Участники, сообщавшие о меньшем количестве негативных эффектов, таких как усталость, головокружение или напряжение глаз во время командообразующей деятельности, достигали более высокого уровня ощущения присутствия.
|
ru
|
We report multifrequency Very Long Baseline Array observations of twelve active galactic nuclei seen toward the Galactic anticenter. All of the sources are at |b| < 10 degrees and seven have |b| < 0.5 degrees. Our VLBA observations can detect an enhancement in the angular broadening of these sources due to an extended H II disk, if the orientation of the H II disk in the outer Galaxy is similar to that of the H I disk. Such an extended H II disk is suggested by the C IV absorption in a quasar's spectrum, the appearance of H I disks of nearby spiral galaxies, and models of Ly-alpha cloud absorbers and the Galactic fountain. We detect eleven of the twelve sources at one or more frequencies; nine of the sources are compact and suitable for an angular broadening analysis. A preliminary analysis of the observed angular diameters suggests that the H II disk does not display considerable warping or flaring and does not extend to large Galactocentric distances (R >~ 100 kpc). A companion paper (Lazio & Cordes 1997) combines these observations with those in the literature and presents a more comprehensive analysis.
|
Předkládáme vícekmitočtová pozorování pomocí Velmi dlouhé základnové sítě (Very Long Baseline Array) dvanácti aktivních galaktických jader pozorovaných směrem ke galaktickému protistředu. Všechny zdroje leží v oblasti |b| < 10 stupňů a sedm z nich má |b| < 0,5 stupně. Naše pozorování pomocí VLBA jsou schopna detekovat zvětšení úhlového rozšíření těchto zdrojů způsobené rozsáhlým diskem H II, pokud je orientace disku H II ve vnější Galaxii podobná orientaci disku H I. Existence takového rozsáhlého disku H II je naznačena absorpcí C IV ve spektru kvasaru, vzhledem disků H I u blízkých spirálních galaxií a modely absorbérů oblaků Ly-alfa a galaktické fontány. Jedenáct ze dvanácti zdrojů jsme detekovali na jedné nebo více frekvencích; devět zdrojů je kompaktních a vhodných pro analýzu úhlového rozšíření. Předběžná analýza pozorovaných úhlových průměrů naznačuje, že disk H II nevykazuje výrazné zkroucení ani rozšíření na okrajích a nevystupuje do velkých galaktocentrických vzdáleností (R >~ 100 kpc). Doplňkový článek (Lazio & Cordes 1997) kombinuje tato pozorování s údaji z literatury a předkládá podrobnější analýzu.
|
cs
|
Let $E$ be a holomorphic vector bundle. Let $\theta$ be a Higgs field, that is a holomorphic section of $End(E)\otimes\Omega^{1,0}_X$ satisfying $\theta^2=0$. Let $h$ be a pluriharmonic metric of the Higgs bundle $(E,\theta)$. The tuple $(E,\theta,h)$ is called a harmonic bundle. Let $X$ be a complex manifold, and $D$ be a normal crossing divisor of $X$. In this paper, we study the harmonic bundle $(E,\theta,h)$ over $X-D$. We regard $D$ as the singularity of $(E,\theta,h)$, and we are particularly interested in the asymptotic behaviour of the harmonic bundle around $D$. We will see that it is similar to the asymptotic behaviour of complex variation of polarized Hodge structures, when the harmonic bundle is tame and nilpotent with the trivial parabolic structure. For example, we prove constantness of general monodromy weight filtrations, compatibility of the filtrations, norm estimates, and the purity theorem. For that purpose, we will obtain a limiting mixed twistor structure from a tame nilpotent harmonic bundle with trivial parabolic structure, on a punctured disc. It is a partial solution of a conjecture of Simpson.
|
فرض کریں کہ $E$ ایک ہولومورفک ویکٹر بندل ہو۔ فرض کریں کہ $\theta$ ایک ہگز فیلڈ ہو، یعنی $End(E)\otimes\Omega^{1,0}_X$ کا ایک ہولومورفک حصہ جو شرط $\theta^2=0$ کو پورا کرتا ہو۔ فرض کریں کہ $h$ ہگز بندل $(E,\theta)$ کا ایک پلوئیر ہارمونک میٹرک ہو۔ ٹوپل $(E,\theta,h)$ کو ایک ہارمونک بندل کہا جاتا ہے۔ فرض کریں کہ $X$ ایک مختلط متغیر بند ہو، اور $D$، $X$ کا ایک نارمل کراسنگ ڈیوائزر ہو۔ اس مقالہ میں، ہم $X-D$ پر ہارمونک بندل $(E,\theta,h)$ کا مطالعہ کرتے ہیں۔ ہم $D$ کو $(E,\theta,h)$ کی قطعیت کے طور پر دیکھتے ہیں، اور ہم خاص طور پر $D$ کے گرد ہارمونک بندل کے مراکزی رویے میں دلچسپی رکھتے ہیں۔ ہم دیکھیں گے کہ جب ہارمونک بندل نرم اور نل پوٹنٹ ہو اور اس کی ساخت بارابولک ساخت سے تراش ہو تو، یہ رویہ مختلط قطبی شدہ ہوڈج ساخت کی مراکزی تبدیلی کے مراکزی رویے کے قریب قریب ہوگا۔ مثال کے طور پر، ہم عمومی مونوڈرومی وزن فلٹریشن کی مستقلیت، فلٹریشن کی مطابقت، نارم تخمینوں، اور خالصیت کے نظریہ کا ثبوت دیتے ہیں۔ اس مقصد کے لیے، ہم ایک نرم نل پوٹنٹ ہارمونک بندل سے جس کی بارابولک ساخت تراش ہو، اور جو ایک منقوص ڈسک پر ہو، ایک لیمٹنگ مکسڈ ٹوئسٹر ساخت حاصل کریں گے۔ یہ سِمپسن کے ایک حدس کا جزوی حل ہے۔
|
ur
|
A major challenge in biology is to understand how molecular processes determine phenotypic features. We address this fundamental problem in a class of model systems by developing a general mathematical framework that allows the calculation of mesoscopic properties from the knowledge of microscopic Markovian transition probabilities. We show how exact analytic formulae for the first and second moments of resident time distributions in mesostates can be derived from microscopic resident times and transition probabilities even for systems with a large number of microstates. We apply our formalism to models of the inositol trisphosphate receptor, which plays a key role in generating calcium signals triggering a wide variety of cellular responses. We demonstrate how experimentally accessible quantities, such as opening and closing times and the coefficient of variation of inter-spike intervals, and other, more elaborated, quantities can be analytically calculated from the underlying microscopic Markovian dynamics. A virtue of our approach is that we do not need to follow the detailed time evolution of the whole system, as we derive the relevant properties of its steady state without having to take into account the often extremely complicated transient features. We emphasize that our formulae fully agree with results obtained by stochastic simulations and approaches based on a full determination of the microscopic system's time evolution. We also illustrate how experiments can be devised to discriminate between alternative molecular models of the inositol trisphosphate receptor. The developed approach is applicable to any system described by a Markov process and, owing to the analytic nature of the resulting formulae, provides an easy way to characterize also rare events that are of particular importance to understand the intermittency properties of complex dynamic systems.
|
បញ្ហាចំបងមួយក្នុងជីវវិទ្យាគឺការយល់ដឹងពីរបៀបដែលដំណើរការម៉ូលេគុលកំណត់លក្ខណៈប្រាកដនៃរូបរាង។ យើងដោះស្រាយបញ្ហាមូលដ្ឋាននេះក្នុងប្រព័ន្ធគំរូមួយក្រុមដោយការអភិវឌ្ឍគ្រប់គ្រងគណិតវិទ្យាទូទៅ ដែលអនុញ្ញាតឱ្យគណនាលក្ខណៈមេសូស្កេល (mesoscopic) ពីប្រូបាបប្តូរទីតាំងរបស់ម៉ាក្រូស្កេល (microscopic Markovian transition probabilities)។ យើងបង្ហាញពីរបៀបដែលរូបមន្តវិភាគដែលត្រឹមត្រូវសម្រាប់ពេលវេលាស្ថិតនៅក្នុងមេសូស្ថានៈ (mesostates) ដែលមានទាំងមធ្យម (first moments) និងវិវដ្ត (second moments) អាចដកស្រង់ចេញពីពេលវេលាស្ថិតនៅក្នុងស្ថានៈម៉ាក្រូ និងប្រូបាបប្តូរទីតាំង ទោះបីជាប្រព័ន្ធមានចំនួនស្ថានៈម៉ាក្រូច្រើនក៏ដោយ។ យើងអនុវត្តវិធីសាកសួររបស់យើងទៅលើគំរូនៃអង់ទីប៉ូឌីអ៊ីនូស៊ីតូលត្រៃស្វ៊ីផូស្វេត (inositol trisphosphate receptor) ដែលមានតួនាទីសំខាន់ក្នុងការបង្កើតសញ្ញាកាល់ស្យូម ដែលជំរុញឱ្យមានប្រតិកម្មកោសិកាច្រើនប្រភេទ។ យើងបង្ហាញពីរបៀបដែលបរិមាណដែលអាចស្វែងរកបានតាមផ្លូវពិសោធន៍ ដូចជាពេលបើក និងបិទ និងមេគុណនៃការប្រែប្រួលនៃចន្លោះពេលរវាងស្ពាយ (inter-spike intervals) និងបរិមាណផ្សេងៗទៀតដែលស្មុគស្មាញជាងនេះ អាចគណនាបានតាមផ្លូវវិភាគពីដំណើរការម៉ាក្រូស្កេលដែលមានលក្ខណៈម៉ាក់កូវ (Markovian dynamics)។ គុណសម្បត្តិមួយនៃវិធីសាកសួររបស់យើងគឺយើងមិនចាំបាច់តាមដានដំណើរវិវត្តន៍ពេលវេលាលម្អិតនៃប្រព័ន្ធទាំងមូលទេ ពីព្រោះយើងដកស្រង់យកលក្ខណៈពាក់ព័ន្ធនៃស្ថានភាពស្ថិតស្ថេររបស់វាដោយមិនចាំបាច់គិតពីលក្ខណៈបណ្តោះអាសន្នដែលច្រើនតែស្មុគស្មាញខ្លាំងណាស់។ យើងសង្កត់ធ្ងន់ថា រូបមន្តរបស់យើងព្រមគ្នាទាំងស្រុងជាមួយលទ្ធផលដែលទទួលបានពីការសមានំរុង (stochastic simulations) និងវិធីសាកសួរដែលផ្អែកលើការកំណត់ពេលវេលារបស់ប្រព័ន្ធម៉ាក្រូស្កេលទាំងមូល។ យើងក៏បង្ហាញផងដែរពីរបៀបដែលអាចរៀបចំការពិសោធន៍ដើម្បីបែងចែករវាងគំរូម៉ូលេគុលផ្សេងៗគ្នាសម្រាប់អង់ទីប៉ូឌីអ៊ីនូស៊ីតូលត្រៃស្វ៊ីផូស្វេត។ វិធីសាកសួរដែលបានអភិវឌ្ឍនេះអាចអនុវត្តបានចំពោះប្រព័ន្ធណាមួយដែលបានពិពណ៌នាដោយដំណើរការម៉ាក់កូវ ហើយដោយសារតែលក្ខណៈវិភាគនៃរូបមន្តដែលទទួលបាន វាផ្តល់នូវវិធីសាមញ្ញក្នុងការគំរូនូវព្រឹត្តិការណ៍កម្រៗ ដែលមានសារៈសំខាន់ជាពិសេសក្នុងការយល់ដឹងពីលក្ខណៈអន្តរកាល (intermittency properties) នៃប្រព័ន្ធដែលមានដំណើរការស្មុគស្មាញ។
|
km
|
In this work we present the main atmospheric parameters, carbon, nitrogen and oxygen abundances, and 12C/13C ratios determined in a sample of 28 Galactic clump stars. Abundances of carbon were studied using the C2 band at 5086.2 {\AA}. The wavelength interval 7980-8130 {\AA} with strong CN features was analysed in order to determine nitrogen abundances and 12C/13C isotope ratios. The oxygen abundances were determined from the [O I] line at 6300 {\AA}. The mean abundances of C, N and O abundances in the investigated clump stars support our previous estimations that, compared to the Sun and dwarf stars of the Galactic disc, carbon is depleted by about 0.2 dex, nitrogen is enhanced by 0.2 dex and oxygen is close to abundances in dwarfs. The 12C/13C and C/N ratios for galactic red clump stars analysed were compared to the evolutionary models of extra-mixing. The steeper drop of 12C/13C ratio in the model of thermohaline mixing by Charbonnel & Lagarde better reflects the observational data at low stellar masses than the more shallow model of cool bottom processing by Boothroyd & Sackmann. For stars of about 2 Msun masses a modelling of rotationally induced mixing should be considered with rotation of about 250 km s-1 at the time when a star was at the hydrogen-core-burning stage.
|
Dalam karya ini kami mempersembahkan parameter atmosfera utama, kelimpahan karbon, nitrogen dan oksigen, serta nisbah 12C/13C yang ditentukan dalam sampel 28 bintang rumpun Galaksi. Kelimpahan karbon dikaji menggunakan jalur C2 pada 5086.2 {\AA}. Julat panjang gelombang 7980-8130 {\AA} yang mengandungi ciri-ciri CN yang kuat dianalisis untuk menentukan kelimpahan nitrogen dan nisbah isotop 12C/13C. Kelimpahan oksigen ditentukan daripada garisan [O I] pada 6300 {\AA}. Kelimpahan purata C, N dan O dalam bintang rumpun yang dikaji menyokong anggaran terdahulu kami bahawa berbanding Matahari dan bintang kerdil cakera Galaksi, karbon berkurang kira-kira 0.2 dex, nitrogen meningkat sebanyak 0.2 dex dan oksigen hampir setara dengan kelimpahan dalam bintang kerdil. Nisbah 12C/13C dan C/N bagi bintang rumpun merah Galaksi yang dianalisis dibandingkan dengan model evolusi pencampuran tambahan. Kecerunan jatuh yang lebih curam bagi nisbah 12C/13C dalam model pencampuran termohalina oleh Charbonnel & Lagarde mencerminkan data pemerhatian dengan lebih baik pada jisim bintang yang rendah berbanding model pencampuran bahagian bawah sejuk oleh Boothroyd & Sackmann yang lebih landai. Bagi bintang dengan jisim kira-kira 2 Msun, pemodelan pencampuran yang diaruhkan oleh putaran perlu dipertimbangkan dengan kelajuan putaran sekitar 250 km s-1 pada ketika bintang berada dalam peringkat pembakaran teras hidrogen.
|
ms
|
Fast Radio Bursts (FRBs) are bright enigmatic radio pulses of roughly millisecond duration that come from extragalactic distances. As part of the MeerTRAP project, we use the MeerKAT telescope array in South Africa to search for and localise those bursts to high precision in real-time. We aim to pinpoint FRBs to their host galaxies and, thereby, to understand how they are created. However, the transient nature of FRBs presents various challenges, e.g. in system design, raw compute power and real-time communication, where the real-time requirements are reasonably strict (a few tens of seconds). Rapid data processing is essential for us to be able to retain high-resolution data of the bursts, to localise them, and to minimise the delay for follow-up observations. We give a short overview of the data analysis pipeline, describe the challenges faced, and elaborate on our initial design and implementation of a real-time triggering infrastructure for FRBs at the MeerKAT telescope.
|
إن الانفجارات الراديوية السريعة (FRBs) هي نبضات راديوية ساطعة ولغزية تبلغ مدتها نحو ميلي ثانية، وتأتي من مسافات خارج المجرة. كجزء من مشروع MeerTRAP، نستخدم تلسكوب مصفوفة ميركات في جنوب إفريقيا للبحث عن هذه الانفجارات وتحديد مواقعها بدقة عالية في الزمن الحقيقي. ونهدف إلى تحديد مواقع الانفجارات الراديوية السريعة بدقة داخل مجراتها المضيفة، وبذلك فهم كيفية تكوينها. ومع ذلك، فإن الطبيعة العابرة للانفجارات الراديوية السريعة تطرح تحديات متعددة، مثل تصميم النظام، والقدرة الحاسوبية الأولية، والتواصل في الزمن الحقيقي، حيث تكون متطلبات الزمن الحقيقي صارمة نسبياً (بضعة عشرات من الثواني). إن المعالجة السريعة للبيانات أمر ضروري بالنسبة لنا لتمكين الاحتفاظ ببيانات الانفجارات ذات الدقة العالية، وتحديد مواقعها، وتقليل التأخير في إجراء الملاحظات اللاحقة. نقدم نظرة عامة موجزة على خط أنابيب تحليل البيانات، ونوضح التحديات التي واجهناها، ونستعرض بالتفصيل التصميم الأولي والتنفيذ البنية التحتية للإطلاق في الزمن الحقيقي للانفجارات الراديوية السريعة في تلسكوب ميركات.
|
ar
|
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.