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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)
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我们获得了引力透镜类星体Q1422+231的极高信噪比、高分辨率光谱，以研究星系际介质（IGM）的金属丰度。我们确定了CIV的柱密度分布函数（CDDF），其可由指数为1.44 ± 0.05的幂律函数很好地拟合。在对不完备性进行校正后，我们发现CDDF在log N(CIV) = 11.75处仍符合幂律分布，比此前确定的灵敏度高十倍。为了确定CIV丰度是否延伸至更低柱密度的HI云中，我们发现对单个像素光学深度的分析比叠加技术更为稳健。我们将该光学深度方法所得结果与采用不同CIV丰度模型的模拟光谱分析结果进行了比较。根据这些模拟，我们得出结论：要重现从数据中确定的光学深度，所需CIV含量超过了目前在Q1422+231中直接探测到的量，这与基于幂律分布分析所得结论一致。（节选）
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Measurement-based quantum computation is a framework of quantum computation, where entanglement is used as a resource and local measurements on qubits are used to drive the computation. It originates from the one-way quantum computer of Raussendorf and Briegel, who introduced the so-called cluster state as the underlying entangled resource state and showed that any quantum circuit could be executed by performing only local measurement on individual qubits. The randomness in the measurement outcomes can be dealt with by adapting future measurement axes so that computation is deterministic. Subsequent works have expanded the discussions of the measurement-based quantum computation to various subjects, including the quantification of entanglement for such a measurement-based scheme, the search for other resource states beyond cluster states and computational phases of matter. In addition, the measurement-based framework also provides useful connections to the emergence of time ordering, computational complexity and classical spin models, blind quantum computation, etc. and has given an alternative, resource-efficient approach to implement the original linear-optic quantum computation of Knill, Laflamme and Milburn. Cluster states and a few other resource states have been created experimentally in various physical systems and the measurement-based approach offers a potential alternative to the standard circuit approach to realize a practical quantum computer.
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পরিমাপ-ভিত্তিক কোয়ান্টাম কম্পিউটেশন কোয়ান্টাম কম্পিউটেশনের একটি কাঠামো, যেখানে জটিলতা (entanglement) একটি সম্পদ হিসাবে ব্যবহৃত হয় এবং কিউবিটগুলির স্থানীয় পরিমাপগুলি কম্পিউটেশন চালানোর জন্য ব্যবহৃত হয়। এটি রাউসেনডরফ ও ব্রিগেলের এক-পথ কোয়ান্টাম কম্পিউটার থেকে উৎপন্ন হয়েছে, যারা জটিল সম্পদ অবস্থার ভিত্তি হিসাবে একটি একত্রীকরণ অবস্থা (cluster state) নামে পরিচিত অবস্থা চালু করেন এবং দেখান যে কোনো কোয়ান্টাম সার্কিট কেবলমাত্র আলাদা আলাদা কিউবিটগুলির স্থানীয় পরিমাপ করে কার্যকর করা যেতে পারে। পরিমাপের ফলাফলের এলোমেলো স্বভাবকে ভবিষ্যতের পরিমাপ অক্ষগুলি সামঞ্জস্য করে নিয়ন্ত্রণ করা যায়, যাতে কম্পিউটেশন নির্ধারিত হয়। পরবর্তী কাজগুলি এই পরিমাপ-ভিত্তিক কম্পিউটেশন সংক্রান্ত আলোচনাকে বিভিন্ন বিষয়ে প্রসারিত করেছে, যার মধ্যে রয়েছে এমন পরিমাপ-ভিত্তিক পদ্ধতির জন্য জটিলতার পরিমাপ, একত্রীকরণ অবস্থার বাইরে অন্যান্য সম্পদ অবস্থার অনুসন্ধান এবং পদার্থের গাণিতিক অবস্থা। এছাড়াও, পরিমাপ-ভিত্তিক কাঠামোটি সময় ক্রমবিন্যাসের উদ্ভব, গাণিতিক জটিলতা এবং ক্লাসিকাল স্পিন মডেল, ব্লাইন্ড কোয়ান্টাম কম্পিউটেশন ইত্যাদির সঙ্গে কার্যকর সংযোগ প্রদান করেছে এবং নিল, লাফলাম্মে ও মিলবার্নের মূল লাইনার-অপটিক কোয়ান্টাম কম্পিউটেশন বাস্তবায়নের জন্য একটি বিকল্প, সম্পদ-দক্ষ পদ্ধতি দিয়েছে। বিভিন্ন পদার্থগত ব্যবস্থাতে পরীক্ষামূলকভাবে একত্রীকরণ অবস্থা এবং কয়েকটি অন্যান্য সম্পদ অবস্থা তৈরি করা হয়েছে এবং পরিমাপ-ভিত্তিক পদ্ধতি একটি বাস্তব কোয়ান্টাম কম্পিউটার বাস্তবায়নের জন্য মানক সার্কিট পদ্ধতির একটি সম্ভাব্য বিকল্প প্রদান করে।
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Relativistic shocks are one of the most plausible sites of the emission of strongly variable, polarized multi-wavelength emission from relativistic jet sources such as blazars, via diffusive shock acceleration (DSA) of relativistic particles. This paper summarizes recent results on a self-consistent coupling of diffusive shock acceleration and radiation transfer in blazar jets. We demonstrate that the observed spectral energy distributions (SEDs) of blazars strongly constrain the nature of hydromagnetic turbulence responsible for pitch-angle scattering by requiring a strongly energy-dependent pitch-angle mean free path. The prominent soft X-ray excess ("Big Blue Bump") in the SED of the BL Lac object AO 0235+164 can be modelled as the signature of bulk Compton scattering of external radiation fields by the thermal electron population, which places additional constraints on the level of hydromagnetic turbulence. It has further been demonstrated that internal shocks propagating in a jet pervaded by a helical magnetic field naturally produce polarization-angle swings by 180$^o$, in tandem with multi-wavelength flaring activity, without requiring any helical motion paths or other asymmetric jet structures. The specific application of this model to 3C279 presents the first consistent, simultaneous modeling of snap-shot SEDs, multi-wavelength light curves and time-dependent polarization signatures of a blazar during a polarization-angle (PA) rotation. This model has recently been generalized to a lepto-hadronic model, in which the high-energy emission is dominated by proton synchrotron radiation. It is shown that in this case, the high-energy (X-ray and $\gamma$-ray) polarization signatures are expected to be significantly more stable (not showing PA rotations) than the low-energy (electron-synchrotron) signatures.
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နှိမ့်ချခံရသော ရိုက်ခတ်မှုများသည် ဘလေဇာများကဲ့သို့သော နှိမ့်ချခံရသည့် ဂျက်အရင်းအမြစ်များမှ ပြင်းထန်စွာ ပြောင်းလဲသည့်၊ သံလိုက်ဝန်းရံမှုရှိသော အလင်းရောင်မျိုးစုံ ထုတ်လွှတ်မှုကို နှိမ့်ချခံရသော အမှုန်များ၏ ပျံ့နှံ့သော ရိုက်ခတ်မှု တိုးမြှင့်မှု (DSA) ကနေတစ်ဆင့် ထုတ်လွှတ်သည့် နေရာများအနက် တစ်ခုအဖြစ် အလားအလာရှိသည်။ ဤစာတမ်းသည် ဘလေဇာဂျက်များတွင် ပျံ့နှံ့သော ရိုက်ခတ်မှု တိုးမြှင့်မှုနှင့် ရောင်ခြည် လွှဲပြောင်းမှုကို ကိုယ်ပိုင် ကိုက်ညီစွာ ချိတ်ဆက်ခြင်းဆိုင်ရာ မကြာသေးမီက ရရှိထားသည့် ရလဒ်များကို စုစည်းဖော်ပြထားသည်။ ဘလေဇာများ၏ စွဲမက်ဖွယ် စွမ်းအင်ဖြန့်ကျက်မှု (SEDs) များသည် ထောင်လိုက် ရွေ့လျားမှု ပျမ်းမျှ အကွာအဝေးကို စွမ်းအင်အဆင့်အလိုက် အလွန်အမင်း မှီခိုနေရသည်ဟု လိုအပ်ချက် ပြုလုပ်ခြင်းဖြင့် ထောင်လိုက် ပြောင်းလဲမှုကို ဖြစ်စေသည့် ဟိုက်ဒရိုမက်ဂျက်နစ် ပြင်ပ လှိုင်းများ၏ သဘောသဘာဝကို အလွန်ကန့်သတ်ထားကြောင်း ကျွန်ုပ်တို့ ပြသထားသည်။ BL Lac အရာဝတ္ထု AO 0235+164 ၏ SED တွင် ထင်ရှားသော နူးညံ့သည့် X-ray အပိုထွက်ရှိမှု ("Big Blue Bump") ကို ပြင်ပ ရောင်ခြည် ကွင်းများကို သာမိုနျူထရွန် အီလက်ထရွန် လူဦးရေများမှ အုပ်စုလိုက် Compton ပြန်လည်တိုက်ခတ်မှု၏ လက္ခဏာအဖြစ် မော်ဒယ်လုပ်နိုင်ပြီး ဟိုက်ဒရိုမက်ဂျက်နစ် ပြင်ပလှိုင်းများ၏ အဆင့်ကို ထပ်မံကန့်သတ်မှုများ ပေးစေသည်။ ထို့အပြင် ဟယ်လစ်ကယ် သံလိုက်ကွင်းဖြင့် ဖြည့်နှီးနေသော ဂျက်အတွင်း ပျံ့နှံ့နေသည့် အတွင်းပိုင်း ရိုက်ခတ်မှုများသည် ဟယ်လစ်ကယ် ရွေ့လျားမှု လမ်းကြောင်းများ သို့မဟုတ် အခြားသော မမှန်မကန် ဂျက် ဖွဲ့စည်းပုံများကို မလိုအပ်ဘဲ မျိုးစုံသော အလင်းရောင်များနှင့် တစ်ပြိုင်နက် လုပ်ဆောင်နေစဉ် 180$^o$ ဖြင့် သံလိုက်ဝန်းရံမှု ထောင့် ရွေ့လျားမှုများကို သဘာဝအတိုင်း ထုတ်လုပ်နိုင်ကြောင်း ထပ်မံပြသထားသည်။ ဤမော်ဒယ်ကို 3C279 တွင် သတ်မှတ် အသုံးချခြင်းသည် သံလိုက်ဝန်းရံမှု ထောင့် (PA) လှည့်ခြင်းအတွင်း ဘလေဇာတစ်ခု၏ အချိန်ကုန်လွန်မှုနှင့်အတူ ဖြစ်ပေါ်သော SED များ၊ မျိုးစုံသော အလင်းရောင် မျဉ်းကြောင်းများနှင့် အချိန်ပေါ် မူတည်သော သံလိုက်ဝန်းရံမှု လက္ခဏာများကို တစ်ပြိုင်နက် ကိုက်ညီစွာ မော်ဒယ်လုပ်နိုင်ခဲ့သည့် ပထမဆုံး ဥပမာဖြစ်သည်။ ဤမော်ဒယ်ကို မကြာသေးမီက လက်ပ်တို-ဟာဒရောနစ် မော်ဒယ်အဖြစ် ယေဘုယျပြုခဲ့ပြီး အထူးသဖြင့် အမြင့်စွာသော စွမ်းအင် ထုတ်လွှတ်မှုသည် ပရိုတွန် စီးန်ခရိုထရွန် ရောင်ခြည်ဖြင့် အဓိက ထိန်းချုပ်ထားသည်။ ဤကိစ္စတွင် အမြင့်စွာသော စွမ်းအင် (X-ray နှင့် $\gamma$-ray) သံလိုက်ဝန်းရံမှု လက္ခဏာများသည် နိမ့်ကျသော စွမ်းအင် (အီလက်ထရွန်-စီးန်ခရိုထရွန်) လက္ခဏာများနှင့် နှိုင်းယှဉ်ပါက သိသိသာသာ ပိုမိုတည်ငြိမ်မှုရှိမည် (PA လှည့်ခြင်း မပြသခြင်း) ဖြစ်ရန် မျှော်လင့်ရကြောင်း ပြသထားသည်။
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We present a comprehensive spectroscopic imaging survey of the distribution and kinematics of atomic hydrogen (HI) in 16 nearby spiral galaxies hosting low luminosity AGN, observed with high spectral and spatial resolution (resolution: ~20 arcsec, 5 km/s) using the NRAO Very Large Array (VLA). The sample contains a range of nuclear types, ranging from Seyfert to star-forming nuclei and was originally selected for the NUclei of GAlaxies project (NUGA) - a spectrally and spatially resolved interferometric survey of gas dynamics in nearby galaxies designed to identify the fueling mechanisms of AGN and the relation to host galaxy evolution. Here we investigate the relationship between the HI properties of these galaxies, their environment, their stellar distribution and their AGN type. The large-scale HI morphology of each galaxy is classified as ringed, spiral, or centrally concentrated; comparison of the resulting morphological classification with AGN type reveals that ring structures are significantly more common in LINER than in Seyfert host galaxies, suggesting a time evolution of the AGN activity together with the redistribution of the neutral gas. Dynamically disturbed HI disks are also more prevalent in LINER host galaxies than in Seyfert host galaxies. While several galaxies are surrounded by companions (some with associated HI emission), there is no correlation between the presence of companions and the AGN type (Seyfert/LINER).
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Біз НАРҚ-ның Үлкен Массивын (VLA) қолданып (бұрыштық шешімділік: ~20 арксек, жылдамдық шешімділігі: 5 км/с), жарықтылығы төмен АЯЯ-ның 16 жақын орналасқан спиральді галактикаларындағы атомдық сутегінің (HI) таралуы мен кинематикасын кеңінен қамтитын спектрлік бейне алу зерттеуін ұсынамыз. Таңдама Сейферт ядросынан бастап жұлдыздық түзілу ядросына дейінгі әртүрлі ядролық типтерді қамтиды және бастапқыда галактикалар ядроларының жобасы (NUGA) үшін таңдалған — бұл жақын орналасқан галактикалардағы газ динамикасының спектрлік және кеңістіктік шешімділігі бар интерферометриялық зерттеу, АЯЯ-ның қоректену механизмдерін және олардың негізгі галактикамен эволюциялық байланысын анықтау мақсатында жасалған. Бұл жерде біз осы галактикалардың HI қасиеттері, олардың қоршаған ортасы, жұлдыздардың таралуы және АЯЯ типі арасындағы байланысты зерттейміз. Әрбір галактиканың үлкен масштабты HI морфологиясы сақиналы, спиральді немесе центрде шоғырланған деп жіктеледі; нәтижесінде алынған морфологиялық жіктеуді АЯЯ типімен салыстыру LINER галактикаларында Сейферт галактикаларына қарағанда сақиналы құрылымдардың айтарлықтай жиі кездесетінін көрсетеді, бұл бейтарап газдың қайта таралуымен бірге АЯЯ белсенділігінің уақыт бойынша эволюциясына әкеледі. Динамикалық бұзылған HI дискілері де LINER галактикаларында Сейферт галактикаларына қарағанда жиірек кездеседі. Бірнеше галактикалар серіктермен қоршалған (кейбіреулеріне HI шығарылуы байланысты), бірақ серіктердің болуы мен АЯЯ типі (Сейферт/LINER) арасында байланыс жоқ.
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kk
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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.
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과학 연구는 지속적인 과정이며, 향후 진전 속도는 이전 연구 질문들에 대한 설명을 찾는 속도로 추정할 수 있다. 항성 맥동과 항성진동학에 대한 관측자 중심의 관점에서 우리는 변광성에 대한 최초의 관측과 이를 관측하기 위해 사용된 기술들로부터 시작한다. 최초의 변광성들은 진폭이 큰 방사형 맥동 별들이었으나, 이후 다른 종류의 맥동성들이 계속 발견되었다. 이 분야가 성숙함에 따라 우리는 관측 기술의 변화에 초점을 맞추어 맥동성 연구의 몇 가지 주요 이정표들을 개관한다. 사진 촬영에서 광도 측정, CCD, 그리고 우주 망원경으로의 발전을 통해 연구자들은 광도 변화를 보이는 다른 별들로부터 맥동성을 가진 별들을 구분할 수 있게 되었고, 측정 정밀도의 향상 덕분에 방사형 및 비방사형 맥동을 인식할 수 있게 되었으며, 이후 비방사형 맥동을 이용해 별 내부를 들여다볼 수 있게 되었는데, 이는 다른 방법으로는 불가능한 일이다. 우리는 몇 가지 주목할 만한 문제들을 따라가며, 훌륭한 우주 관측 데이터가 있더라도 이에 대한 이론적 설명이 즉각적으로 나오지 않을 수 있음을 보여준다. 기술적 변화의 결과로 맥동성 연구에 헌신하는 국제 기구들의 구조가 변화하였으며, 우주 임무나 특정 주제에 특화된 회의들이 점점 더 많이 개최되고 있다. 비점근적 맥동성에서의 진동 모드 식별과 같은 해결되지 않은 문제가 여전히 많지만, 우주 임무(MOST, CoRoT, Kepler)와 향후 예정된 임무들에 의해 제공되는 전례 없는 정밀도의 방대한 데이터 덕분에 항성진동학을 그 잠재력의 극한까지 활용할 수 있게 되었다. 그러나 엄청난 양의 데이터 흐름은 다음 임무 이전에 과학적 성과를 추출하기 위한 새로운 기술을 요구할 것이다. 우리는 과거로부터 배우고, 개선된 기술과 우주 임무, 그리고 적절히 교육받은 새로운 세대와 함께 발전한다면, 항성진동학의 미래는 성공할 것이다.
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ko
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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.
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نقترح تطوير قاعدة بيانات تجريبية للإيونات الثقيلة ذات الطاقة العالية وجعلها متاحة للمجتمع العلمي من خلال واجهة إلكترونية. ستكون هذه القاعدة قابلة للبحث ومرتبطة بشكل متقاطع بالمنشورات ذات الصلة، بما في ذلك وصفات الكاشفة المنشورة. وبما أن هذه القاعدة تمثل مورداً مجتمعياً، فإنها تتطلب دعماً مالياً وبدنياً من مجتمع فيزياء النوى عالية الطاقة. ينبغي أن تحتوي هذه القاعدة في نهاية المطاف على جميع البيانات المنشورة من بيفالاك وAGS وSPS وحتى طاقات RHIC وLHC، ومن التصادمات البروتون-بروتون إلى التصادمات نواة-نواة، فضلاً عن الأنظمة الأخرى ذات الصلة وجميع الكميات القابلة للقياس التي تم قياسها. سيكون لهذا النوع من قواعد البيانات عائد علمي هائل، إذ يسهل الدراسات المنظمة ويجعل المقارنة مع النماذج النظرية عبر نطاق واسع من التجارب القديمة والحديثة أكثر سهولة. علاوة على ذلك، هناك حاجة متزايدة لتجميعات بيانات النوى عالية الطاقة في تطبيقات تشمل الإشراف على المخزون النووي، وتطوير التكنولوجيا للاندماج المحفور بالقصور الذاتي، وتطوير الأهداف والمصادر للمرافق المستقبلية مثل المُسرّع الخطي القادم. ولتعزيز فائدة هذه القاعدة، نقترح إجراء تقييمات دورية للبيانات وتلخيص النتائج في مراجعات متخصصة.
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ar
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We combine the catalogs of compact high-velocity HI clouds extracted from the LDS and HIPASS surveys and analyze the all-sky properties of the ensemble. Five principal observables are defined for the CHVC population: (1) the spatial deployment of the objects on the sky, (2) the kinematic distribution, (3) the number distribution of observed HI column densities, (4) the number distribution of angular sizes, and (5) the number distribution of HI linewidth. Two classes of models are considered to reproduce the observed properties. The agreement of models with the data is judged by extracting these same observables from simulations, in a manner consistent with the sensitivities of the observations and explicitly taking account of Galactic obscuration. We show that models in which the CHVCs are the HI counterparts of dark-matter halos evolving in the Local Group potential provide a good match to the observables. The best-fitting populations have a maximum HI mass of 10^7 M_Sun a power-law slope of the HI mass distribution in the range -1.7 to -1.8, and a Gaussian dispersion for their spatial distributions of between 150 and 200 kpc centered on both the Milky Way and M31. Given its greater mean distance, only a small fraction of the M31 sub-population is predicted to have been detected in present surveys. An empirical model for an extended Galactic halo distribution for the CHVCs is also considered. While reproducing some aspects of the population, this class of models does not account for some key systematic features of the population.
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我们将从LDS和HIPASS巡天中提取的致密高速中性氢云（CHVC）星表进行合并，并分析该整体样本的全天特性。我们为CHVC总体定义了五个主要可观测量：（1）天体在天空中的空间分布，（2）运动学分布，（3）观测到的中性氢柱密度的数目分布，（4）角尺寸的数目分布，以及（5）中性氢谱线宽度的数目分布。我们考虑了两类模型以重现观测特性。通过以与观测灵敏度一致的方式从模拟中提取相同的可观测量，并明确考虑银河系遮挡效应，来评估模型与数据的符合程度。我们发现，若将CHVC视为在本星系群引力势中演化的暗物质晕的中性氢对应体，则此类模型能很好地匹配所有可观测量。最符合的总体具有约10^7倍太阳质量的最大中性氢质量，中性氢质量分布的幂律指数在-1.7至-1.8之间，其空间分布呈高斯型，相对于银河系和M31中心的弥散尺度介于150至200千秒差距之间。由于M31子总体的平均距离更远，预计目前巡天仅探测到其中一小部分。我们也考虑了一种经验性的CHVC银河系晕延展分布模型。尽管该类模型能够重现部分总体特征，但无法解释该总体中一些关键的系统性特征。
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zh
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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.
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Una publicación reciente proporciona el grafo de red para un microcircuito neocortical que comprende 8 millones de conexiones entre 31.000 neuronas (H. Markram et al., Reconstrucción y simulación de la microcircuitría neocortical, Cell, 163 (2015) n.º 2, 456-492). Dado que los métodos tradicionales de teoría de grafos podrían no ser suficientes para comprender la inmensa complejidad de una red biológica como esta, exploramos si los métodos de la topología algebraica podrían ofrecer una nueva perspectiva sobre su organización estructural y funcional. El análisis topológico estructural reveló que los grafos dirigidos que representan la conectividad entre neuronas en el microcircuito se desviaban significativamente de diversas variedades de grafos aleatorizados. En particular, los grafos dirigidos contenían del orden de $10^7$ símplices {\DH} grupos de neuronas con conectividad dirigida total a total. Algunos de estos símplices contenían hasta 8 neuronas, lo que los convierte en el motivo de agrupamiento neuronal más extremo jamás reportado. El análisis topológico funcional de la actividad neuronal simulada en el microcircuito reveló nuevas métricas espacio-temporales que proporcionan una clasificación efectiva de las respuestas funcionales a estímulos cualitativamente diferentes. Este estudio representa el primer análisis topológico algebraico de la conectómica estructural y de la actividad espacio-temporal basada en conectómica en un microcircuito neuronal biológicamente realista. Los métodos utilizados en el estudio muestran potencial para aplicaciones más generales en la ciencia de redes.
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es
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We present an analysis of the optical spectroscopy of 58 stars in the Galactic plane at $l=27$\arcdeg, where a prominent excess in the flux distribution and star counts have been observed in several spectral regions, in particular in the Two Micron Galactic Survey (TMGS) catalog. The sources were selected from the TMGS, to have a $K$ magnitude brighter than +5 mag and be within 2 degrees of the Galactic plane. More than 60% of the spectra correspond to stars of luminosity class I, and a significant proportion of the remainder are very late giants which would also be fast evolving. This very high concentration of young sources points to the existence of a major star formation region in the Galactic plane, located just inside the assumed origin of the Scutum spiral arm. Such regions can form due to the concentrations of shocked gas where a galactic bar meets a spiral arm, as is observed at the ends of the bars of face-on external galaxies. Thus, the presence of a massive star formation region is very strong supporting evidence for the presence of a bar in our Galaxy.
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আমরা আকাশগঙ্গার তলের $l=27$\arcdeg অবস্থানে 58টি তারার আলোক বর্ণালীবিদ্যার একটি বিশ্লেষণ উপস্থাপন করছি, যেখানে বিভিন্ন আলোক বর্ণালী অঞ্চলে, বিশেষ করে টু মাইক্রন গ্যালাকটিক সার্ভে (TMGS) ক্যাটালগে, ফ্লাক্স বন্টন এবং তারা গণনায় একটি সুস্পষ্ট অতিরিক্ততা লক্ষ্য করা গেছে। TMGS থেকে উৎসগুলি নির্বাচন করা হয়েছিল যাদের $K$ মাত্রা +5 mag-এর চেয়ে উজ্জ্বল এবং গ্যালাকটিক তল থেকে 2 ডিগ্রির মধ্যে অবস্থিত। বর্ণালীগুলির 60% এর বেশি আলোকমাত্রা শ্রেণী I-এর তারার সাথে মিলে যায় এবং বাকি অংশের একটি উল্লেখযোগ্য অংশ খুবই পরবর্তী দৈত্য তারা যারা দ্রুত বিবর্তিত হচ্ছে বলে মনে হয়। এই অত্যন্ত উচ্চ ঘনত্বে যুব উৎসগুলি আকাশগঙ্গার তলে একটি প্রধান তারা গঠন অঞ্চলের অস্তিত্বের ইঙ্গিত দেয়, যা ধরে নেওয়া স্কুটাম ঘূর্ণন বাহুর উৎপত্তির ঠিক ভিতরে অবস্থিত। এমন অঞ্চলগুলি গঠিত হতে পারে সেখানে যেখানে আকাশগঙ্গার দণ্ড একটি ঘূর্ণন বাহুর সাথে মিলিত হয় এবং আঘাতপ্রাপ্ত গ্যাসের ঘনত্ব ঘটে, যেমনটা মুখোমুখি বাহ্যিক আকাশগঙ্গাগুলির দণ্ডের প্রান্তগুলিতে পর্যবেক্ষণ করা যায়। সুতরাং, একটি বৃহৎ তারা গঠন অঞ্চলের উপস্থিতি আমাদের আকাশগঙ্গাতে একটি দণ্ডের উপস্থিতির জন্য খুবই শক্তিশালী সমর্থনমূলক প্রমাণ হিসাবে কাজ করে।
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bn
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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.
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Penelitian ilmiah merupakan proses yang berkelanjutan, dan kecepatan kemajuan di masa depan dapat diperkirakan dari laju penemuan penjelasan atas pertanyaan penelitian sebelumnya. Dalam pandangan berbasis pengamat terhadap getaran bintang dan asteroseismologi ini, kami memulai dengan pengamatan paling awal terhadap bintang variabel serta teknik-teknik yang digunakan untuk mengamatinya. Bintang variabel pertama yang diamati adalah bintang berdenyut radial dengan amplitudo besar, namun kemudian diikuti oleh kelas-kelas lain bintang berdenyut. Seiring berkembangnya bidang ini, kami menguraikan beberapa tonggak penting dalam penelitian bintang berdenyut dengan penekanan pada perubahan teknik pengamatan. Perkembangan dari teknik fotografi, fotometri, CCD, hingga teleskop luar angkasa memungkinkan para peneliti memisahkan bintang berdenyut dari bintang lain yang mengalami variasi cahaya, mengenali denyut radial dan nonradial berkat peningkatan ketepatan pengukuran, dan kemudian menggunakan denyut nonradial untuk mengamati bagian dalam bintang, yang tidak dapat dilakukan dengan cara lain. Kami mengikuti beberapa permasalahan utama untuk menunjukkan bahwa meskipun data luar angkasa sangat baik, penjelasan teoretis yang cepat belum tentu muncul. Sebagai akibat dari perubahan teknis tersebut, struktur organisasi internasional yang berfokus pada bintang berdenyut juga berubah, dan semakin banyak konferensi khusus yang diselenggarakan, baik yang berfokus pada misi luar angkasa maupun tema tertentu. Meskipun masih banyak masalah yang belum terpecahkan, seperti identifikasi mode pada bintang berdenyut non-asimtotik, jumlah besar data dengan ketepatan yang belum pernah terjadi sebelumnya dari misi luar angkasa (MOST, CoRoT, Kepler) dan misi-misi mendatang memungkinkan kita memanfaatkan asteroseismologi secara maksimal. Namun, aliran data yang sangat besar ini akan memerlukan teknik-teknik baru untuk mengekstraksi ilmu pengetahuan sebelum misi-misi berikutnya. Masa depan asteroseismologi akan sukses jika kita belajar dari masa lalu, terus memperbaiki diri melalui teknik-teknik yang lebih baik, misi luar angkasa, serta generasi baru yang terdidik dengan baik.
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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).
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Uma discussão crítica sobre o estado atual dos experimentos do CERN sobre a dinâmica do charme e o fluxo coletivo de hádrons é apresentada. Enfatizamos a importância da função de excitação do fluxo entre 1 e 50 A$\cdot$GeV: aqui, o modelo hidrodinâmico previu o colapso do fluxo $v_1$ e do fluxo $v_2$ em $\sim 10$ A$\cdot$GeV; em 40 A$\cdot$GeV, essa observação foi recentemente feita pela colaboração NA49. Como modelos de rescatamento hadrônico prevêem um fluxo muito maior do que o observado nessa energia, interpretamos essa observação como evidência potencial de uma transição de fase de primeira ordem em alta densidade barionica $\rho_B$. Segue-se uma discussão detalhada do fluxo coletivo como um barômetro para a equação de estado (EoS) da matéria quente e densa no RHIC. Além disso, estudos detalhados de transporte mostram que a supressão do jato do lado oposto pode ser apenas parcialmente ($<$ 50%) devida ao rescatamento hadrônico. Finalmente, propomos melhorias e experimentos de segunda geração no RHIC que investiguem a transição de fase de primeira ordem na região de fragmentação, ou seja, em $\mu_B \approx 400$ MeV ($y \approx 4-5$), onde o colapso do fluxo de prótons deverá ser observado, em analogia aos dados em 40 A$\cdot$GeV. O estudo dos potenciais de "Jet-Wake-riding" e de choques de proa — causados por jatos no PGC formado no RHIC — pode fornecer informações adicionais sobre a equação de estado (EoS) e os coeficientes de transporte do Plasma de Quarks e Glúons (PGC).
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The recently-discovered stellar system in Canis Major is analysed using He-burning Red Clump stars as tracers. Canis Major turns out to be the strongest and most spatially confined overdensity of the whole Galactic Disc, both in terms of number density and of statistical significance. When projected onto the Galactic Plane, it appears as an elongated and compact overdensity extending from l ~ 200 to l ~ 280 with a roundish core toward l ~ 240. We find that the main body of the system has an integrated absolute magnitude M_V=-14.4 +/- 0.8, a central surface brightness \mu_{V,0} = 24.0 +/- 0.6 mag/arcsec^2 and a line-of-sight profile peaked at D_{sun}=7.2 +/- 1.0 kpc with Half Width at Half Maximum ~ 2.0 kpc, in excellent agreement with the results obtained with widely different tracers (M giants and Main Sequence stars) in previous analyses. The mean distance to the main body of Canis Major is observed to increase with increasing Galactic longitude, from D_{sun} ~ 6.3 kpc at l ~ 225, to D_{sun} ~ 9.3 kpc at l ~ 265, in good agreement with the predictions of our more recent N-body simulation that models CMa as a dwarf galaxy being accreted in a planar orbit onto the disc of the Milky Way. We confirm that the Canis Major system has all the characteristics of the relic of a dwarf galaxy seen on top of a large-scale overdensity that we detect all over the third and fourth Galactic quadrants (180<l<360, with a strong maximum around l=290 and b> -5) that is identified as the stellar component of the southern Galactic Warp... (Abridged)....
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ລະບົບດາວທີ່ຖືກຄົ້ນພົບໃໝ່ໃນກຸ່ມດາວ Canis Major ໄດ້ຖືກວິເຄາະໂດຍໃຊ້ດາວ Red Clump ທີ່ເຜົາໄໝ້ຮັງສີ He ເປັນຕົວຕິດຕາມ. Canis Major ພົບວ່າເປັນບັນດາພື້ນທີ່ທີ່ມີຄວາມໜາແໜ້ນເກີນໄປ (overdensity) ທີ່ເຂັ້ມແຂງທີ່ສຸດ ແລະ ມີຂອບເຂດໃນອະວະກາດທີ່ຊັດເຈນທີ່ສຸດໃນທຸກພື້ນທີ່ຈານຂອງກາແລັກຊີ ທັງໃນດ້ານຄວາມໜາແໜ້ນຂອງຈຳນວນ ແລະ ຄວາມໝາຍທາງສະຖິຕິ. ເມື່ອຖືກໂຄ້ນລົງໃສ່ແບບພິມຂອງກາແລັກຊີ ມັນປາກົດຕົວເປັນພື້ນທີ່ມີຄວາມໜາແໜ້ນເກີນໄປທີ່ຍືດຍາວ ແລະ ມີຂອບເຂດກະທັດຮັດ ເຊິ່ງກະຈາຍຕົວຈາກ l ~ 200 ເຖິງ l ~ 280 ໂດຍມີສ່ວນກາງທີ່ມົນກົມກ່ຽວກັບ l ~ 240. ພວກເຮົາພົບວ່າຕົວຫຼັກຂອງລະບົບນີ້ມີຂະໜາດແສງສະຫວ່າງສຳພັດ M_V=-14.4 +/- 0.8, ມີຄວາມສະຫວ່າງຜິວໜ້າກາງ \mu_{V,0} = 24.0 +/- 0.6 mag/arcsec^2 ແລະ ແຜ່ນໂປຣໄຟລ໌ຕາມທິດສະດີດ່ຽວ (line-of-sight) ທີ່ສູງສຸດຢູ່ທີ່ D_{sun}=7.2 +/- 1.0 kpc ໂດຍມີຄວາມກວ້າງກາງທີ່ຄຳນວນຈາກຄ່າສູງສຸດ (Half Width at Half Maximum) ປະມານ 2.0 kpc, ທີ່ກົງກັນດີກັບຜົນໄດ້ຮັບຈາກການໃຊ້ຕົວຕິດຕາມທີ່ແຕກຕ່າງກັນຢ່າງກວ້າງຂວາງ (ດາວ M giants ແລະ ດາວ Main Sequence) ໃນການວິເຄາະກ່ອນໜ້ານີ້. ພວກເຮົາສັງເກດເຫັນວ່າໄລຍະທາງສະເລ່ຍໄປຫາຕົວຫຼັກຂອງ Canis Major ເພີ່ມຂຶ້ນຕາມຄວາມຍາວຂອງກາແລັກຊີທີ່ເພີ່ມຂຶ້ນ, ຈາກ D_{sun} ~ 6.3 kpc ທີ່ l ~ 225 ເຖິງ D_{sun} ~ 9.3 kpc ທີ່ l ~ 265, ຊຶ່ງກົງກັບຄາດໝາຍຈາກການສຳຫຼວດ N-body ລ້າສຸດຂອງພວກເຮົາ ທີ່ຈຳລອງການດູດຊຶມຂອງ CMa ເຂົ້າມາໃນວົງໂຄຈອນແບບດິດ (planar orbit) ໃສ່ຈານຂອງກາແລັກຊີ Milky Way. ພວກເຮົາຢືນຢັນວ່າລະບົບ Canis Major ມີຄຸນລັກສະນະທັງໝົດຂອງເງົາເຫຼືອຈາກດາວຄູ່ນ້ອຍ (dwarf galaxy) ທີ່ຖືກມອງເຫັນຢູ່ເທິງພື້ນທີ່ໜາແໜ້ນຂະໜາດໃຫຍ່ ທີ່ພວກເຮົາພົບເຫັນຢູ່ທົ່ວຈຸດທີ່ສາມ ແລະ ສີ່ຂອງກາແລັກຊີ (180<l<360, ມີຈຸດສູງສຸດຢ່າງເດັ່ນຢູ່ l=290 ແລະ b> -5) ທີ່ຖືກຈຳແນກວ່າເປັນສ່ວນປະກອບຂອງດາວທີ່ເກີດຈາກການເບື່ອງຂອງກາແລັກຊີດ້ານໃຕ້... (ຫຍໍ້)...
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lo
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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.
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លេខកូដប្រភព (បរិបទ) និងដើមឈើវាក្យសម្បទាដែលបានវិភាគ (AST; រចនាសម្ព័ន្ធ) គឺជាការតំណាងពីរប្រភេទបំពេញបន្ថែមគ្នាសម្រាប់កម្មវិធីកុំព្យូទ័រតែមួយ។ ប្រពៃណីមក អ្នករចនាម៉ូដែលរៀនសូត្រពីម៉ាស៊ីន បានពឹងផ្អែកជាចម្បងលើរចនាសម្ព័ន្ធ ឬបរិបទ។ យើងស្នើម៉ូដែលថ្មីមួយ ដែលរៀនរួមគ្នាលើបរិបទ និងរចនាសម្ព័ន្ធនៃលេខកូដប្រភព។ ផ្ទុយពីវិធីសាស្ត្រមុនៗ ម៉ូដែលរបស់យើងប្រើតែលក្ខណៈទូទៅសម្រាប់ភាសា ឧទាហរណ៍ លេខកូដប្រភព និងលក្ខណៈដែលអាចគណនាបានដោយផ្ទាល់ពី AST។ ក្រៅពីទទួលបានលទ្ធផលដ៏ល្អបំផុតនៅលើការសង្ខេបកូដតែមួយភាសាលើភាសាសរសេរកម្មវិធីទាំងប្រាំដែលពិចារណាក្នុងការងារនេះ យើងស្នើម៉ូដែលសង្ខេបកូដពហុភាសាដំបូងគេ។ យើងបង្ហាញថា ការបណ្តុះបណ្តាលរួមគ្នាលើទិន្នន័យមិនស្មើគ្នាពីភាសាសរសេរកម្មវិធីច្រើន បានធ្វើឱ្យលទ្ធផលប្រសើរឡើងលើភាសានីមួយៗ ដែលការកើនឡើងខ្លាំងបំផុតគឺនៅលើភាសាដែលមានធនធានទាប។ គួរកត់សម្គាល់ថា ការបណ្តុះបណ្តាលពហុភាសាតាមរយៈបរិបទតែមួយគត់ មិននាំទៅរកការកែលម្អដូចគ្នានោះទេ ដែលបញ្ជាក់ពីអត្ថប្រយោជន៍នៃការបញ្ចូលរចនាសម្ព័ន្ធ និងបរិបទសម្រាប់ការរៀនតំណាងលើកូដ។
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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.
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Una pubblicazione recente fornisce il grafo di rete per un microcircuito neocorticale composto da 8 milioni di connessioni tra 31.000 neuroni (H. Markram et al., Reconstruction and simulation of neocortical microcircuitry, Cell, 163 (2015) n. 2, 456-492). Poiché i metodi tradizionali della teoria dei grafi potrebbero non essere sufficienti a comprendere l'enorme complessità di una rete biologica di questo tipo, abbiamo esplorato se metodi della topologia algebrica potessero offrire una nuova prospettiva sulla sua organizzazione strutturale e funzionale. L'analisi topologica strutturale ha rivelato che i grafi diretti rappresentanti la connettività tra neuroni nel microcircuito si discostano significativamente da diverse varietà di grafi randomizzati. In particolare, i grafi diretti contenevano nell'ordine di $10^7$ simplessi {\DH} gruppi di neuroni con connettività diretta totalizzata. Alcuni di questi simplessi contenevano fino a 8 neuroni, risultando così il motivo di aggregazione neuronale più estremo mai riportato. L'analisi topologica funzionale dell'attività neuronale simulata nel microcircuito ha rivelato nuove metriche spazio-temporali che forniscono una classificazione efficace delle risposte funzionali a stimoli qualitativamente diversi. Questo studio rappresenta la prima analisi topologica algebrica della connettomica strutturale e dell'attività spazio-temporale basata sulla connettomica in un microcircuito neurale biologicamente realistico. I metodi utilizzati nello studio mostrano potenzialità per applicazioni più generali nella scienza delle reti.
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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.
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Le anisotropie di temperatura della radiazione cosmica di fondo (CMB) mostrano un'asimmetria dipolare su larga scala nella potenza. Per determinare se ciò sia dovuto a una modulazione fisica reale o semplicemente a una grande fluttuazione statistica, è necessario misurare nuove modalità. In questo lavoro prevediamo con quale precisione i dati sulla polarizzazione della CMB del satellite \Planck\ e di futuri esperimenti potranno confermare o vincolare modelli fisici di modulazione. Adattando diversi di questi modelli ai dati di temperatura di \Planck, siamo in grado di fornire previsioni per l'asimmetria di polarizzazione. Mentre per alcuni modelli e parametri i dati di polarizzazione di \Planck\ ridurranno le barre di errore sull'ampiezza della modulazione solo di una piccola percentuale, mostriamo, in modo importante, che dati sulla polarizzazione limitati dalla varianza cosmica (e in alcuni casi persino quelli di \Planck) possono ridurre gli errori notevolmente meglio del fattore atteso di $\sqrt 2$ basato su semplici argomentazioni nello spazio-$\ell$. Prevediamo che, se le fluttuazioni primordiali sono effettivamente modulate (con parametri indicati dai dati di temperatura di \Planck), \Planck\ sarà in grado di effettuare una rivelazione a 2$\sigma$ del modello di modulazione con una probabilità compresa tra il 20% e il 75%, che aumenta al 45–99% quando si considerano dati di polarizzazione limitati dalla varianza cosmica. Sottolineiamo che questi risultati dipendono fortemente dal modello. La varianza cosmica nella temperatura è importante: combinare dati di polarizzazione statisticamente isotropi con i dati di temperatura aumenterebbe in modo spurio la significatività del segnale di temperatura con una probabilità del 30% per \Planck.
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it
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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.
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은하 반대쪽 중심 방향으로 관측된 12개의 활동은하핵에 대한 다중주파수 초장기선 배열(Very Long Baseline Array, VLBA) 관측 결과를 보고한다. 모든 천체는 |b| < 10도에 위치하며, 7개는 |b| < 0.5도에 있다. 외부 은하에서 H II 성운 원반의 방향이 H I 성운 원반의 방향과 유사하다면, 우리의 VLBA 관측은 이러한 천체들의 각도 확장이 확장된 H II 원반으로 인해 증가하는 현상을 감지할 수 있다. 이러한 확장된 H II 원반의 존재는 준성계(quasar) 스펙트럼에서 나타나는 C IV 흡수, 인근 나선은하들의 H I 원반 형태, 리만-알파 구름 흡수체 모델 및 은하 분수(갤럭틱 파운틴) 모델에 의해 제시된다. 12개의 천체 중 11개를 하나 이상의 주파수에서 감지하였으며, 이 중 9개는 콤팩트하여 각도 확장 분석에 적합하다. 관측된 각지름에 대한 예비 분석 결과에 따르면, H II 원반은 상당한 비틀림이나 퍼짐(warping or flaring)을 나타내지 않으며, 큰 은하중심 거리(R >~ 100 kpc)까지 확장되지 않는다. 동반 논문(Lazio & Cordes 1997)은 본 관측 결과를 문헌상의 다른 관측과 통합하여 보다 포괄적인 분석을 제시한다.
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ko
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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.
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Rajadas Rápidas de Rádio (FRBs) são pulsos de rádio brilhantes e enigmáticos com duração de aproximadamente um milissegundo que vêm de distâncias extragalácticas. Como parte do projeto MeerTRAP, utilizamos a matriz de telescópios MeerKAT na África do Sul para buscar e localizar essas rajadas com alta precisão em tempo real. Nosso objetivo é identificar com exatidão as galáxias hospedeiras das FRBs e, assim, compreender como elas são geradas. No entanto, a natureza transitória das FRBs apresenta diversos desafios, por exemplo, no projeto do sistema, no poder bruto de computação e na comunicação em tempo real, em que os requisitos de tempo real são razoavelmente rigorosos (algumas dezenas de segundos). O processamento rápido de dados é essencial para que possamos manter dados de alta resolução das rajadas, localizá-las e minimizar o atraso para observações de acompanhamento. Apresentamos uma breve visão geral do pipeline de análise de dados, descrevemos os desafios enfrentados e detalhamos nosso projeto inicial e implementação de uma infraestrutura de detecção em tempo real para FRBs no telescópio MeerKAT.
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pt
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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.
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우리는 헤일로 붉은 왜성(가장 희미한 수소 연소 별)에 대한 질량 함수(MF)를 도출한 후, 이를 외삽하여 헤일로 갈색 왜성(수소 연소에 충분한 질량이 부족한 별)의 총 질량에 대한 한계를 설정한다. 질량 함수는 USNO 시차 조사(Dahn \etal 1995)에서 얻은 국부 헤일로 별 114개로 구성된 표본의 광도 함수로부터 구하였다. 우리는 Alexander \etal(1996)의 항성 모델을 사용하며, 표본의 금속량 및 미해결 이중성계의 존재 가능성에 대해 다양한 가정을 두었다. 그 결과, 수소 연소 한계에 접근할수록 헤일로 붉은 왜성의 질량 함수는 $1/m^2$보다 더 급격히 증가할 수 없음을 발견하였다. 항성 형성 이론의 최근 결과를 이용하여, 질량 함수를 갈색 왜성 영역까지 외삽하였다. 외삽 결과, 헤일로 내 갈색 왜성의 총 질량은 헤일로의 국부 질량 밀도의 약 3% 미만임을 알 수 있었으며(고려한 모델 중 더 현실적인 모델의 경우 약 0.3%)이다. 본 연구의 한계는 붉은 왜성과 동일한 항성 집단에서 기원한 헤일로 내 갈색 왜성에 적용된다.
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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).
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Một thảo luận nghiêm ngặt về tình trạng hiện tại của các thí nghiệm tại CERN về động lực học hạt lạ (charm) và dòng chảy tập thể của hadron được trình bày. Chúng tôi nhấn mạnh tầm quan trọng của hàm kích thích dòng chảy trong khoảng từ 1 đến 50 A$\cdot$GeV: tại đây, mô hình thủy động lực học đã dự đoán sự sụp đổ của dòng $v_1$ và dòng $v_2$ ở khoảng 10 A$\cdot$GeV; hiện tượng này gần đây đã được hợp tác NA49 quan sát thấy ở 40 A$\cdot$GeV. Vì các mô hình tái tán xạ hadron dự đoán dòng chảy lớn hơn nhiều so với quan sát được ở năng lượng này, chúng tôi diễn giải quan sát này như một bằng chứng tiềm tàng cho sự chuyển pha bậc nhất tại mật độ barion cao $\rho_B$. Tiếp theo là một thảo luận chi tiết về dòng chảy tập thể như một thang đo phương trình trạng thái (EoS) của vật chất nóng, đậm đặc tại RHIC. Ngoài ra, các nghiên cứu vận chuyển chi tiết cho thấy rằng sự ức chế tia phun phía xa (away-side jet suppression) chỉ có thể một phần ($<$ 50%) là do tái tán xạ hadron. Cuối cùng, chúng tôi đề xuất các nâng cấp và các thí nghiệm thế hệ thứ hai tại RHIC nhằm khảo sát chuyển pha bậc nhất trong vùng phân mảnh, tức là tại $\mu_B \approx 400$ MeV ($y \approx 4-5$), nơi mà sự sụp đổ của dòng proton cần phải được quan sát thấy tương tự như dữ liệu ở 40 A$\cdot$GeV. Việc nghiên cứu các thế năng Jet-Wake-riding và các sóng xung kích mũi tên (Bow shocks) — gây ra bởi các tia phun trong QGP hình thành tại RHIC — có thể cung cấp thêm thông tin về phương trình trạng thái (EoS) và các hệ số vận chuyển của Plasma Quark-Gluon (QGP).
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vi
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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%.
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大量のラベル付き訓練データは、深層モデルが過去に大きな成功を収めた主な要因の一つである。ベンチマーク以外のタスクにおいては、資金と専門知識の両方を必要とするため、ラベルの取得は困難となる場合がある。ラベル付けされていない事例のうち、モデルの改善という観点から有望なもののみを選択し、そのラベルだけを取得することで、アクティブラーニングはラベル付けプロセスの時間的・コスト的な効率を高めることができる。本研究では、増分学習方式とアクティブラーニング手法を組み合わせた方法について述べる。これにより、新たに観測されたラベルなしデータを継続的に探索することが可能になる。モデルの不確実性および予想されるモデル出力の変化（EMOC）に基づく選択基準について説明する。PASCAL VOCデータセットを用いて、物体検出タスクを継続的探索の文脈で評価した。また、カメラトラップで取得した画像を解析する実世界の生物多様性アプリケーションにおいて、アクティブラーニングと増分学習に基づく弱教師ありシステムの有効性を検証した。本手法が生成する候補を承認または拒否することで、わずか32枚の画像にラベルを付けるだけで、精度が25.4%から42.6%まで向上した。
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Nowadays, the use of agile software development methods like Scrum is common in industry and academia. Considering the current attacking landscape, it is clear that developing secure software should be a main concern in all software development projects. In traditional software projects, security issues require detailed planning in an initial planning phase, typically resulting in a detailed security analysis (e.g., threat and risk analysis), a security architecture, and instructions for security implementation (e.g., specification of key sizes and cryptographic algorithms to use). Agile software development methods like Scrum are known for reducing the initial planning phases (e.g., sprint 0 in Scrum) and for focusing more on producing running code. Scrum is also known for allowing fast adaption of the emerging software to changes of customer wishes. For security, this means that it is likely that there are no detailed security architecture or security implementation instructions from the start of the project. It also means that a lot of design decisions will be made during the runtime of the project. Hence, to address security in Scrum, it is necessary to consider security issues throughout the whole software development process. Secure Scrum is a variation of the Scrum framework with special focus on the development of secure software throughout the whole software development process. It puts emphasis on implementation of security related issues without the need of changing the underlying Scrum process or influencing team dynamics. Secure Scrum allows even non- security experts to spot security issues, to implement security features, and to verify implementations. A field test of Secure Scrum shows that the security level of software developed using Secure Scrum is higher then the security level of software developed using standard Scrum.
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Hoy en día, el uso de métodos ágiles de desarrollo de software como Scrum es común en la industria y en el ámbito académico. Considerando el panorama actual de ataques, es evidente que desarrollar software seguro debería ser una preocupación principal en todos los proyectos de desarrollo de software. En proyectos de software tradicionales, los problemas de seguridad requieren una planificación detallada en una fase inicial de planificación, lo que generalmente resulta en un análisis de seguridad detallado (por ejemplo, análisis de amenazas y riesgos), una arquitectura de seguridad e instrucciones para la implementación de seguridad (por ejemplo, especificación de tamaños de claves y algoritmos criptográficos a utilizar). Se sabe que los métodos ágiles de desarrollo de software como Scrum reducen las fases iniciales de planificación (por ejemplo, el sprint 0 en Scrum) y se centran más en producir código funcional. Scrum también es conocido por permitir una rápida adaptación del software emergente a los cambios en los deseos del cliente. En cuanto a la seguridad, esto significa que es probable que no exista desde el inicio del proyecto una arquitectura de seguridad detallada ni instrucciones específicas para la implementación de seguridad. También significa que muchas decisiones de diseño se tomarán durante la ejecución del proyecto. Por lo tanto, para abordar la seguridad en Scrum, es necesario considerar los aspectos de seguridad durante todo el proceso de desarrollo de software. Secure Scrum es una variante del marco Scrum con especial énfasis en el desarrollo de software seguro a lo largo de todo el proceso de desarrollo. Pone énfasis en la implementación de cuestiones relacionadas con la seguridad sin necesidad de modificar el proceso Scrum subyacente ni influir en la dinámica del equipo. Secure Scrum permite incluso a personas no expertas en seguridad detectar problemas de seguridad, implementar funciones de seguridad y verificar implementaciones. Una prueba de campo de Secure Scrum muestra que el nivel de seguridad del software desarrollado utilizando Secure Scrum es mayor que el nivel de seguridad del software desarrollado utilizando Scrum estándar.
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es
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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.
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6次元超共形場理論（SCFT）のコンパクト化によって生成される4次元理論のクラスをより深く理解することを目的として、我々はクラスS_Gamma理論、すなわちM5ブレーンがADE特異点をプローブすることによって得られる6次元SCFTに対して、N = 1超対称性を持つパンクチャの構造を研究する。M5ブレーンがC^2 / Z_k特異点をプローブする場合、パンクチャは時間発展がアフィンA型キラーモデルの隣接ノードへの移動に対応する力学系によって支配される。パンクチャの分類は、周期軌道を生じる一貫した初期条件を決定することに帰着する。この系の研究は、単一のM5ブレーンの場合に特に扱いやすい。この「単純な」場合でさえ、解は顕著な複雑さを示す。初期運動量が特定の有理数値の場合にのみ周期軌道が生じ、わずかな摂動が遅い時間での挙動に大きく異なる影響を与える。クラスS理論の1/2BPSパンクチャとは異なり、いくつかのパンクチャ解には連続な複素「ゼロモード」モジュールが現れる点も異なる。高次の極を持つパンクチャの構成は、関連する再帰関係の集合を含む。得られる構造は、複数のM5ブレーン系やD型、E型のオービフォルド特異点をプローブする系へも一般化される。
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ja
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The Gemini Deep Deep Survey, GDDS, produced several significant results relating to the evolution of galaxies. All of these results are consistent with the "downsizing" concept of galaxy formation and evolution, i.e., that the active periods of star formation moved progressively from very massive galaxies at high redshift to much lower mass galaxies at the present epoch. Spectra of massive red galaxies at z ~ 1.7 demonstrates that they contain old stellar populations and hence must have formed their stars in the first ~3 Gyr of cosmic history; indicators of star formation activity show that the star formation rate in the most massive galaxies was much higher at z = 2 than today, that the activity in intermediate mass galaxies peaked near z ~ 1.5, while, since z ~ 1 the activity is primarily confined to lower mass galaxies. The GDDS also uncovered a relatively high percentage of post-starburst galaxies at z ~ 1, a result that is anticipated given all the activity seen at higher redshifts. Measurements of the strengths of metal lines of a subsample of the GDDS and CFRS galaxies at z ~ 0.7 reveal that, at a given mass, they had lower metallicities than at present. The evolution in the mass-metallicity relation is consistent with a model in which star formation lasts longest in less massive galaxies, again an expected result in the downsizing scenario.
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Gemini Derin Derin Taraması (GDDS), galaksilerin evrimiyle ilgili birkaç önemli sonuç ortaya koymuştur. Bu sonuçların tümü galaksi oluşumu ve evriminin "küçülme" (downsizing) kavramıyla uyumludur; yani yıldız oluşumunun aktif dönemleri, yüksek kırmızıya kaymanın olduğu zamanlarda çok kütleli galaksilerde başlayıp, zaman içinde bugünkü dönemde çok daha düşük kütleli galaksilere doğru kaymıştır. Z ~ 1.7 civarındaki büyük kütleli kırmızı galaksilerin tayfları, bu galaksilerin eski yıldız popülasyonlarını içerdiğini ve dolayısıyla yıldızlarını kozmik tarihin ilk yaklaşık 3 milyar yılında oluştuğunu göstermektedir; yıldız oluşumu etkinliğini gösteren belirteçler, en büyük kütleli galaksilerdeki yıldız oluşum hızının z = 2'de günümüzden çok daha yüksek olduğunu, orta kütleli galaksilerdeki etkinliğin z ~ 1.5 civarında zirveye ulaştığını ve z ~ 1'den bu yana etkinliğin çoğunlukla daha düşük kütleli galaksilere sınırlı kaldığını ortaya koymaktadır. GDDS ayrıca z ~ 1 civarında görece yüksek bir oranda yıldız oluşumundan sonra kalan galaksiler (post-starburst galaxies) ortaya çıkarmıştır ve bu, daha yüksek kırmızıya kaymalarda gözlenen tüm bu etkinlikler dikkate alındığında beklenen bir sonuçtur. GDDS ve CFRS galaksilerinin bir alt örneğindeki metal çizgilerinin z ~ 0.7'deki ölçümleri, belirli bir kütlede, bu galaksilerin şu ankinden daha düşük metalikitelere sahip olduğunu göstermektedir. Kütle-metalikite ilişkisindeki bu evrim, yıldız oluşumunun daha düşük kütleli galaksilerde daha uzun sürdüğü bir modelle uyumlu olup, bu da yine küçülme senaryosunda beklenen bir sonuçtur.
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tr
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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 $\Theta\left(N\right)$.
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Keunggulan adaptivitas dan umpan balik sangat menarik dalam pemrosesan sinyal dan komunikasi, dengan berbagai hasil positif dan negatif. Meskipun telah ditunjukkan bahwa adaptivitas tidak memberikan pengurangan substansial terhadap kesalahan kuadrat rata-rata minimaks untuk jumlah pengukuran yang tetap, hasil-hasil yang ada telah menunjukkan beberapa keuntungan adaptivitas dalam hal kompleksitas rekonstruksi, akurasi deteksi dukungan, dan peningkatan rasio sinyal terhadap derau, di bawah kendala energi penginderaan. Energi penginderaan sering kali diukur dalam bentuk Norma Frobenius dari matriks penginderaan. Makalah ini menggunakan metrik berbeda yang kami sebut biaya $l_0$ dari matriks penginderaan—untuk mengukur kompleksitas penginderaan. Dengan demikian, matriks penginderaan renggang memiliki biaya yang lebih rendah. Kami menurunkan batas bawah teoretis informasi pada biaya $l_0$ yang berlaku untuk setiap strategi penginderaan non-adaptif. Kami menunjukkan bahwa setiap strategi penginderaan non-adaptif harus menanggung biaya $l_0$ sebesar $\Theta\left( N \log_2(N)\right) $ untuk merekonstruksi sinyal satu-renggang berdimensi-$N$ ketika jumlah pengukuran dibatasi hingga $\Theta\left(\log_2 (N)\right)$. Sebagai perbandingan, strategi adaptif tipe pembagian dua hanya memerlukan biaya $l_0$ paling banyak $\mathcal{O}(N)$ untuk jumlah pengukuran yang sama. Masalah ini memiliki interpretasi menarik sebagai masalah pengepakan bola dalam ruang berdimensi banyak, sedemikian sehingga semua pusat bola memiliki koordinat non-nol minimum. Kami juga membahas variasi biaya $l_0$ saat jumlah pengukuran meningkat dari $\Theta\left(\log_2 (N)\right)$ hingga $\Theta\left(N\right)$.
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id
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In this paper, we investigate a distributed optimal control problem for a convective viscous Cahn-Hilliard system with dynamic boundary conditions. Such systems govern phase separation processes between two phases taking place in an incompressible fluid in a container and, at the same time, on the container boundary. The cost functional is of standard tracking type, while the control is exerted by the velocity of the fluid in the bulk. In this way, the coupling between the state (given by the associated order parameter and chemical potential) and control variables in the governing system of nonlinear partial differential equations is bilinear, which presents an additional difficulty for the analysis. The nonlinearities in the bulk and surface free energies are of logarithmic type, which entails that the thermodynamic forces driving the phase separation process may become singular. We show existence for the optimal control problem under investigation, prove the Fr\'echet differentiability of the associated control-to-state mapping in suitable Banach spaces and derive the first-order necessary optimality conditions in terms of a variational inequality and the associated adjoint system. Due to the strong nonlinear couplings between state variables and control, the corresponding proofs require a considerable analytical effort.
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اس تحقیقی مقالے میں، ہم دینامی سرحدی شرائط کے ساتھ ایک کنویکٹو وِسکس کاہن ہلیارڈ نظام کے لیے تقسیم شدہ مثالی کنٹرول کے مسئلے کا جائزہ لیتے ہیں۔ اس قسم کے نظام ایک بے ترتیب سیال میں ایک برتن کے اندر دو مراحل کے درمیان مرحلہ علیحدگی کے عمل کو حکمرانی کرتے ہیں، اور اسی وقت برتن کی سرحد پر بھی۔ قیمتی فنکشنل معیاری ٹریکنگ قسم کا ہے، جبکہ کنٹرول بیچ میں سیال کی رفتار کے ذریعے عمل میں لایا جاتا ہے۔ اس طریقے سے، حکمرانی کرنے والے غیر خطی جزوی مساوات کے نظام میں حالت (متعلقہ آرڈر پیرامیٹر اور کیمیائی ممکنہ کی صورت میں) اور کنٹرول متغیرات کے درمیان ربط دو خطی ہوتا ہے، جو تجزیہ کے لیے ایک اضافی دشواری پیش کرتا ہے۔ بیچ اور سطحی آزاد توانائیوں میں غیر خطیت لاگرتھم قسم کی ہے، جس کا مطلب ہے کہ مرحلہ علیحدگی کے عمل کو حرکت دینے والی تھرمو ڈائنامک قوتیں منفرد ہو سکتی ہیں۔ ہم تحقیق زیرِ التوا مثالی کنٹرول مسئلے کے وجود کو ظاہر کرتے ہیں، مناسب بینچ جگہوں میں متعلقہ کنٹرول سے حالت تک نگاشن کی فریشے مختلف قابلیت کو ثابت کرتے ہیں، اور ایک متغیر نامساوات اور متعلقہ معاون نظام کے لحاظ سے پہلے درجے کی ضروری مثالیت کی شرائط کا اندازہ لگاتے ہیں۔ حالت متغیرات اور کنٹرول کے درمیان شدید غیر خطی ربط کی وجہ سے، ان متعلقہ ثبوتوں کو مناسب تجزیاتی کوشش کی ضرورت ہوتی ہے۔
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ur
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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.
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最近の出版物により、3万1000個のニューロン間の800万の接続からなる新皮質マイクロサーキットのネットワークグラフが提供された（H. マークランら、「新皮質マイクロサーキットの再構成とシミュレーション」、Cell、163巻（2015年）、2号、456–492頁）。このような生物ネットワークの極めて複雑な構造を理解するには、従来のグラフ理論的手法では不十分である可能性があるため、代数的トポロジーの手法がその構造的・機能的組織について新たな視点を提供できるかどうかを検討した。構造的トポロジー解析により、マイクロサーキット内のニューロン間の接続関係を表す有向グラフは、さまざまな種類のランダム化グラフと有意に逸脱していることが明らかになった。特に、これらの有向グラフには、完全に双方向接続されたニューロンのグループである単体（シンプレックス）が約10の7乗個存在した。これらの単体の中には最大8個のニューロンを含むものもあり、これまでに報告された中で最も極端なニューロンクラスタリングモチーフとなっている。マイクロサーキットにおけるシミュレートされたニューロン活動に対する機能的トポロジー解析により、質的に異なる刺激に対する機能的応答を効果的に分類できる新たな時空間的指標が明らかになった。本研究は、生物学的に現実的な神経マイクロサーキットにおける構造的コネクトミクスおよびコネクトミクスに基づく時空間活動に対して、初めて代数的トポロジー的解析を適用した事例である。本研究で用いられた手法は、ネットワーク科学全般へのより広範な応用可能性を示している。
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ja
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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.
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Dalam karya ini kami menyajikan parameter atmosfer utama, kelimpahan karbon, nitrogen, dan oksigen, serta rasio 12C/13C yang ditentukan dalam sampel 28 bintang raksasa klaster galaksi. Kelimpahan karbon dipelajari menggunakan pita C2 pada 5086,2 {\AA}. Interval panjang gelombang 7980-8130 {\AA} yang memiliki ciri-ciri CN yang kuat dianalisis untuk menentukan kelimpahan nitrogen dan rasio isotop 12C/13C. Kelimpahan oksigen ditentukan dari garis [O I] pada 6300 {\AA}. Rata-rata kelimpahan C, N, dan O pada bintang klaster yang diteliti mendukung estimasi sebelumnya bahwa, dibandingkan dengan Matahari dan bintang kerdil pada piringan Galaksi, karbon berkurang sekitar 0,2 dex, nitrogen meningkat sekitar 0,2 dex, dan oksigen hampir setara dengan kelimpahan pada bintang kerdil. Rasio 12C/13C dan C/N untuk bintang raksasa merah klaster galaksi yang dianalisis dibandingkan dengan model evolusi pencampuran tambahan. Penurunan yang lebih curam dari rasio 12C/13C dalam model pencampuran termohalin oleh Charbonnel & Lagarde lebih mencerminkan data pengamatan pada massa bintang rendah dibandingkan model pencampuran cool bottom processing oleh Boothroyd & Sackmann yang lebih landai. Untuk bintang dengan massa sekitar 2 massa matahari, perlu dipertimbangkan pemodelan pencampuran yang dipicu rotasi dengan kecepatan rotasi sekitar 250 km s-1 pada saat bintang berada pada tahap pembakaran inti hidrogen.
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id
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The current early stage in the investigation of the stability of the Kerr metric is characterized by the study of appropriate model problems. Particularly interesting is the problem of the stability of the solutions of the Klein-Gordon equation, describing the propagation of a scalar field in the background of a rotating (Kerr-) black hole. Results suggest that the stability of the field depends crucially on its mass $\mu$. Among others, the paper provides an improved bound for $\mu$ above which the solutions of the reduced, by separation in the azimuth angle in Boyer-Lindquist coordinates, Klein-Gordon equation are stable. Finally, it gives new formulations of the reduced equation, in particular, in form of a time-dependent wave equation that is governed by a family of unitarily equivalent positive self-adjoint operators. The latter formulation might turn out useful for further investigation. On the other hand, it is proved that from the abstract properties of this family alone it cannot be concluded that the corresponding solutions are stable.
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কার মেট্রিকের স্থিতিশীলতা নির্ণয়ের তদন্তের বর্তমান প্রাথমিক পর্যায়টি উপযুক্ত মডেল সমস্যাগুলির অধ্যয়নের মাধ্যমে চিহ্নিত করা হয়েছে। বিশেষভাবে আকর্ষণীয় হল ক্লাইন-গর্ডন সমীকরণের সমাধানগুলির স্থিতিশীলতার সমস্যা, যা একটি ঘূর্ণায়মান (কার-) ব্ল্যাক হোলের পটভূমিতে একটি স্কেলার ক্ষেত্রের প্রসারণ বর্ণনা করে। ফলাফলগুলি নির্দেশ করে যে ক্ষেত্রটির স্থিতিশীলতা তার ভর $\mu$-এর উপর নির্ভর করে। এর মধ্যে অন্যান্য বিষয়ের পাশাপাশি, এই গবেষণাপত্রটি $\mu$-এর জন্য একটি উন্নত সীমা দেয় যার উপরে বয়ার-লিন্ডকুইস্ট স্থানাঙ্কে দিগন্ত কোণে পৃথকীকরণের মাধ্যমে হ্রাসকৃত ক্লাইন-গর্ডন সমীকরণের সমাধানগুলি স্থিতিশীল হয়। অবশেষে, হ্রাসকৃত সমীকরণের নতুন সূত্র দেওয়া হয়, বিশেষত, একটি সময়-নির্ভর তরঙ্গ সমীকরণের আকারে যা ইউনিটারি সমতুল্য ধনাত্মক স্ব-সংযুক্ত অপারেটরের একটি পরিবার দ্বারা নিয়ন্ত্রিত হয়। পরবর্তী তদন্তের জন্য এই শেষোক্ত সূত্রটি উপযোগী হতে পারে। অন্যদিকে, এটি প্রমাণিত হয়েছে যে এই পরিবারের শুধুমাত্র বিমূর্ত বৈশিষ্ট্যগুলি থেকে এর অনুরূপ সমাধানগুলি স্থিতিশীল তা সিদ্ধান্ত নেওয়া যাবে না।
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bn
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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).
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CERN의 캐릭터 동역학 및 하드론 집단 흐름 실험 현황에 대한 비판적 논의를 제시한다. 우리는 1~50 A·GeV 범위에서의 흐름 여기 함수의 중요성을 강조한다. 이 범위에서 수역학적 모델은 약 10 A·GeV에서 $v_1$-흐름과 $v_2$-흐름의 붕괴를 예측하였으며, 실제로 NA49 협력단에 의해 40 A·GeV에서 최근 관측되었다. 하드론 재산란 모델은 이 에너지 영역에서 관측된 것보다 훨씬 큰 흐름을 예측하기 때문에, 우리는 이 관측 결과를 고바리온 밀도 $\rho_B$에서 1차 상전이의 잠재적 증거로 해석한다. 이어서 RHIC에서 생성되는 고온 밀도 물질의 상태방정식(EoS)을 측정하는 지표로서 집단 흐름에 대해 상세히 논의한다. 또한 정교한 전이 모델 연구에 따르면 제트의 반대편 억제 현상은 하드론 재산란에 의해 부분적으로만($<$ 50%) 설명될 수 있다. 마지막으로, 우리는 파편화 영역, 즉 $\mu_B \approx 400$ MeV ($y \approx 4-5$)에서 1차 상전이를 조사할 수 있는 RHIC의 업그레이드 및 차세대 실험을 제안한다. 여기서는 40 A·GeV 데이터와 유사하게 양성자 흐름의 붕괴가 관측되어야 한다. 또한 RHIC에서 생성된 쿼크-글루온 플라즈마(QGP) 내에서 제트가 유도하는 제트-웨이크-라이딩 포텐셜과 볼록 충격파(Bow shocks)를 연구함으로써 QGP의 상태방정식(EoS) 및 전이 계수들에 대한 추가 정보를 얻을 수 있다.
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ko
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The GEM project is designed for the next generation 2 beta decay experiments with 76-Ge. One ton of ''naked'' HP Ge detectors (natural at the first GEM-I phase and enriched in 76-Ge to 86% at the second GEM-II stage) are operating in super-high purity liquid nitrogen contained in the Cu vacuum cryostat (sphere with diameter 5 m). The latest is placed in the water shield. Monte Carlo simulation evidently shows that sensitivity of the experiment (in terms of the T1/2 limit for neutrinoless 2 beta decay) is 10^27 yr with natural HP Ge crystals and 10^28 yr with enriched ones. These bounds corresponds to the restrictions on the neutrino mass less than 0.05 eV and 0.015 eV with natural and enriched detectors, respectively. Besides, the GEM-I set up could advance the current best limits on the existence of neutralinos - as dark matter candidates - by three order of magnitudes, and at the same time would be able to identify unambiguously the dark matter signal by detection of its seasonal modulation.
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GEM жобасы 76-Ge изотопы үшін келесі ұрпақ 2 бета ыдырау тәжірибелеріне арналған. Бір тонналық «ашық» HP Ge детекторлары (бірінші GEM-I кезеңінде табиғи және екінші GEM-II кезеңінде 76-Ge-ге 86%-ға дейін байытылған) мыс вакуумдық криостатта (диаметрі 5 м болатын сфера) орналасқан супер таза сұйық азотта жұмыс істейді. Соңғысы сулы қорғаныс қабықшасының ішінде орналасқан. Монте-Карло симуляциясы тәжірибенің (нейтриносыз 2 бета ыдырау үшін T1/2 шегі бойынша) сезімталдығы табиғи HP Ge кристалдары үшін 10^27 жыл, ал байытылған кристалдар үшін 10^28 жыл болатынын көрсетеді. Бұл шектер сәйкесінше табиғи және байытылған детекторлар үшін нейтрино массасының 0,05 эВ және 0,015 эВ-тан төмен болуына сәйкес келеді. Сонымен қатар, GEM-I орнатымы нейтралдылардың — қара заттың мүмкін кандидаттарының — бар болуы бойынша қазіргі ең жақсы шектерді үш реттік шамаға жақсартуға мүмкіндік береді және бір уақытта жыл мезгілдеріне байланысты өзгеруін байқау арқылы қара заттың сигналын анық айырып тани алады.
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kk
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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.
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Эхокардиографияда (эхо) әдетте әртүрлі жүрек көріністерін өлшемдерді бағалау үшін уақыт бойынша біріктіру үшін электрокардиограмма (ЭКГ) қолданылады. Алайда, авариялық жағдайларда немесе медициналық көмектің нүктесіндегі жағдайларда ЭКГ алу мүмкін болмай қалады, сондықтан альтернативті уақыттық синхрондау әдістерінің қажеттілігі туындайды. Бұл жерде біз сыртқы ешқандай кіріс мәліметсіз әртүрлі көлденең 2D эхо серияларын синхрондау үшін өзін-өзі басқарылатын оқыту негізінде құрылған Echo-SyncNet ұсынамыз. Ұсынылған негіз бір эхо киноның кадрлары арасындағы кеңістікті-уақыттық үлгілерге негізделген ішкі көрініс бойынша және бірнеше кинолар арасындағы өзара тәуелділікке негізделген көріністер арасындағы өзін-өзі басқару тәсілдерін пайдаланады. Біріктірілген басқару әдістері көптеген эхо киноларын уақыт бойынша синхрондауға болатын ерекшеліктерге бай ендіру кеңістігін оқып үйрену үшін қолданылады. Біз бұл негізді бірнеше тәжірибелер арқылы бағалаймыз: 1) 998 науқастың деректерін қолдана отырып, Echo-SyncNet апикалық 2 камералы және апикалық 4 камералы жүрек көріністерін синхрондау бойынша перспективалы нәтижелер көрсетті; 2) 3070 науқастың деректерін қолдана отырып, жүргізілген тәжірибелерімізде Echo-SyncNet оқып үйренген бейнелері детальды жүрек фазасын автоматты түрде анықтауға оптимизацияланған қадамды терең оқыту әдісінен асып түсетіні анықталды; 3) Жүрек кілттік кадрын анықтау бойынша бір үлгілі оқыту жағдайында оқып үйренілген бейнелердің пайдалылығын көрсетеміз. Ешқандай қосымша баптаусыз, тек бір белгіленген салыстыру зерттеуімен синхрондау арқылы 1188 тексеру науқастарының зерттеулерінде кілттік кадрлар анықталды. Біз оқытуда қандай нақты жүрек көріністерінің қолданылатыны туралы алдын ала шарт қоймаймыз және Echo-SyncNet оның оқыту жинағында болмаған көріністерге дәлме-дәл жалпылай алатынын көрсетеміз. Жобаның сақтау орны: github.com/fatemehtd/Echo-SyncNet.
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kk
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We present ALMA and ACA [CI]$^{3}P_{1}-^{3}P_{0}$ ([CI](1-0)) observations of NGC6240, which we combine with ALMA CO(2-1) and IRAM PdBI CO(1-0) data to study the physical properties of the massive molecular (H$_2$) outflow. We discover that the receding and approaching sides of the H$_2$ outflow, aligned east-west, exceed 10 kpc in their total extent. High resolution ($0.24"$) [CI](1-0) line images surprisingly reveal that the outflow emission peaks between the two AGNs, rather than on either of the two, and that it dominates the velocity field in this nuclear region. We combine the [CI](1-0) and CO(1-0) data to constrain the CO-to-H$_2$ conversion factor ($\alpha_{\rm CO}$) in the outflow, which is on average $2.1\pm1.2~\rm M_{\odot} (K~km~s^{-1}~pc^2)^{-1}$. We estimate that $60\pm20$ % of the total H$_2$ gas reservoir of NGC6240 is entrained in the outflow, for a resulting mass-loss rate of $\dot{M}_{\rm out}=2500\pm1200~M_{\odot}~yr^{-1}$ $\equiv 50\pm30$ SFR. This energetics rules out a solely star formation-driven wind, but the puzzling morphology challenges a classic radiative-mode AGN feedback scenario. For the quiescent gas we compute $\langle\alpha_{\rm CO}\rangle = 3.2\pm1.8~\rm M_{\odot} (K~km~s^{-1}~pc^2)^{-1}$, which is at least twice the value commonly employed for (U)LIRGs. We observe a tentative trend of increasing $r_{21}\equiv L^{\prime}_{\rm CO(2-1)}/L^{\prime}_{\rm CO(1-0)}$ ratios with velocity dispersion and measure $r_{21}>1$ in the outflow, whereas $r_{21}\simeq1$ in the quiescent gas. We propose that molecular outflows are the location of the warmer, strongly unbound phase that partially reduces the opacity of the CO lines in (U)LIRGs, hence driving down their global $\alpha_{\rm CO}$ and increasing their $r_{21}$ values.
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Nous présentons des observations d'ALMA et de l'ACA de la raie [CI]$^{3}P_{1}-^{3}P_{0}$ ([CI](1-0)) de NGC6240, que nous combinons avec des données ALMA de la raie CO(2-1) et des données IRAM PdBI de la raie CO(1-0) afin d'étudier les propriétés physiques de l'important flux de sortie moléculaire (H$_2$). Nous découvrons que les composantes s'éloignant et s'approchant du flux de sortie d'H$_2$, alignées est-ouest, dépassent 10 kpc en extension totale. Des images haute résolution ($0.24"$) de la raie [CI](1-0) révèlent de manière surprenante que l'émission du flux de sortie est maximale entre les deux noyaux actifs, plutôt que sur l'un ou l'autre, et qu'elle domine le champ de vitesses dans cette région nucléaire. Nous combinons les données [CI](1-0) et CO(1-0) afin de contraindre le facteur de conversion CO-H$_2$ ($\alpha_{\rm CO}$) dans le flux de sortie, dont la valeur moyenne est $2.1\pm1.2~\rm M_{\odot} (K~km~s^{-1}~pc^2)^{-1}$. Nous estimons que $60\pm20$ % du réservoir total de gaz H$_2$ de NGC6240 est entraîné dans le flux de sortie, ce qui correspond à un taux de perte de masse de $\dot{M}_{\rm out}=2500\pm1200~M_{\odot}~yr^{-1}$ $\equiv 50\pm30$ SFR. Cette énergie écarte un vent uniquement entraîné par la formation d'étoiles, mais la morphologie énigmatique contredit également un scénario classique de rétroaction d'AGN en mode radiatif. Pour le gaz tranquille, nous calculons $\langle\alpha_{\rm CO}\rangle = 3.2\pm1.8~\rm M_{\odot} (K~km~s^{-1}~pc^2)^{-1}$, valeur au moins deux fois supérieure à celle généralement utilisée pour les (U)LIRG. Nous observons une tendance préliminaire à l'augmentation des rapports $r_{21}\equiv L^{\prime}_{\rm CO(2-1)}/L^{\prime}_{\rm CO(1-0)}$ avec la dispersion de vitesse, et mesurons $r_{21}>1$ dans le flux de sortie, tandis que $r_{21}\simeq1$ dans le gaz tranquille. Nous proposons que les flux de sortie moléculaires soient le lieu d'une phase plus chaude et fortement non liée, qui réduit partiellement l'opacité des raies CO dans les (U)LIRG, abaissant ainsi leur $\alpha_{\rm CO}$ global et augmentant leurs valeurs de $r_{21}$.
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fr
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We develop a robust coarse-grained model for single and double stranded DNA by representing each nucleotide by three interaction sites (TIS) located at the centers of mass of sugar, phosphate, and base. The resulting TIS model includes base-stacking, hydrogen bond, and electrostatic interactions as well as bond-stretching and bond angle potentials that account for the polymeric nature of DNA. The choices of force constants for stretching and the bending potentials were guided by a Boltzmann inversion procedure using a large representative set of DNA structures extracted from the Protein Data Bank. Some of the parameters in the stacking interactions were calculated using a learning procedure, which ensured that the experimentally measured melting temperatures of dimers are faithfully reproduced. Without any further adjustments, the calculations based on the TIS model reproduces the experimentally measured salt and sequence dependence of the size of single stranded DNA (ssDNA), as well as the persistence lengths of poly(dA) and poly(dT) chains. Interestingly, upon application of mechanical force the extension of poly(dA) exhibits a plateau, which we trace to the formation of stacked helical domains. In contrast, the force-extension curve (FEC) of poly(dT) is entropic in origin, and could be described by a standard polymer model. We also show that the persistence length of double stranded DNA is consistent with the prediction based on the worm-like chain. The persistence length, which decreases with increasing salt concentration, is in accord with the Odijk-Skolnick-Fixman theory intended for stiff polyelectrolyte chains near the rod limit. The range of applications, which did not require adjusting any parameter after the initial construction based solely on PDB structures and melting profiles of dimers, attests to the transferability and robustness of the TIS model for ssDNA and dsDNA.
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Мы разработали надежную модель крупнозернистого описания одноцепочечной и двуцепочечной ДНК, представляя каждый нуклеотид тремя точками взаимодействия (TIS), расположенными в центрах масс сахара, фосфата и основания. Полученная модель TIS включает взаимодействия, обусловленные стэкингом оснований, водородными связями и электростатикой, а также потенциалы растяжения связей и угловых потенциалов, учитывающие полимерную природу ДНК. Выбор силовых констант для потенциалов растяжения и изгиба был осуществлен с помощью процедуры инверсии Больцмана, использующей большой репрезентативный набор структур ДНК, извлеченных из Protein Data Bank. Некоторые параметры в потенциалах стэкинга были рассчитаны с применением процедуры обучения, что обеспечило точное воспроизведение экспериментально измеренных температур плавления димеров. Без каких-либо дополнительных корректировок расчеты на основе модели TIS воспроизводят экспериментально измеренные зависимости размера одноцепочечной ДНК (ssDNA) от концентрации соли и последовательности, а также длины персистентности цепей poly(dA) и poly(dT). Интересно, что при приложении механической силы удлинение poly(dA) демонстрирует плато, которое мы связываем с формированием упорядоченных спиральных доменов. В отличие от этого, кривая «сила-удлинение» (FEC) poly(dT) имеет энтропийную природу и может быть описана стандартной полимерной моделью. Мы также показываем, что длина персистентности двуцепочечной ДНК согласуется с предсказанием, основанным на модели червеобразной цепи. Длина персистентности, уменьшающаяся с ростом концентрации соли, согласуется с теорией Одайка—Сколника—Фиксмана, предназначенной для жестких полиэлектролитных цепей вблизи предела жесткого стержня. Широкий диапазон применимости, не потребовавший настройки каких-либо параметров после первоначальной конструкции, основанной исключительно на структурах из PDB и профилях плавления димеров, свидетельствует о переносимости и надежности модели TIS для ssDNA и dsDNA.
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ru
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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.
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Schnelle Radioblitze (FRBs) sind helle, rätselhafte Radiopulse mit einer Dauer von etwa einer Millisekunde, die aus extragalaktischen Entfernungen stammen. Im Rahmen des MeerTRAP-Projekts nutzen wir das Teleskop-Array MeerKAT in Südafrika, um diese Pulse in Echtzeit zu suchen und mit hoher Präzision zu lokalisieren. Unser Ziel ist es, FRBs bis zu ihren Wirtsgalaxien genau zuzuordnen und dadurch zu verstehen, wie sie entstehen. Die transiente Natur der FRBs bringt jedoch verschiedene Herausforderungen mit sich, beispielsweise bei der Systemgestaltung, der benötigten Rechenleistung und der Echtzeitkommunikation, wobei die Anforderungen an die Echtzeitverarbeitung recht streng sind (einige zehn Sekunden). Eine schnelle Datenverarbeitung ist für uns entscheidend, um hochauflösende Daten der Pulse speichern zu können, sie zu lokalisieren und die Verzögerung für Nachbeobachtungen möglichst gering zu halten. Wir geben einen kurzen Überblick über die Datenanalyse-Pipeline, beschreiben die auftretenden Herausforderungen und erläutern unsere anfängliche Konzeption und Implementierung einer Echtzeit-Auslöseinfrastruktur für FRBs am MeerKAT-Teleskop.
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de
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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.
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تقسیم شدہ تولید، قابل تجدید توانائی کے وسائل، توانائی ذخیرہ کرنے کے نظام اور لوڈ ری ایکشن کی تیز رفتار ترقی اور بڑے پیمانے پر ادراج کے ساتھ جدید بجلی کے نظام کا آپریشن غیر یقینی صورتحال اور بار بار تبدیلیوں کی بنا پر کافی حد تک پیچیدہ ہو چکا ہے۔ موجودہ تجارتی توانائی انتظامی نظام (EMS) کی محدود معلوماتی صلاحیت کی وجہ سے موجودہ آپریشن کے خطرات میں اضافہ ہوا ہے۔ اس مقالے میں، متطور گراف پر مبنی ایک اعلی کارکردگی والے EMS تجزیہ کا ڈھانچہ تیار کیا گیا ہے۔ بجلی کے جال کو پہلے ایک متطور گراف کے طور پر ماڈل کیا جاتا ہے، پھر بجلی کے نظام کے متحرک تجزیہ کے اطلاقات جیسے نیٹ ورک ٹاپولوجی پروسیسنگ (NTP)، حالت کا تخمینہ (SE)، بجلی کا بہاؤ (PF)، اور اضطراری تجزیہ (CA) کو نظام کے متطور گراف پر مؤثر طریقے سے نافذ کیا جاتا ہے تاکہ ایک اعلی کارکردگی والے EMS تجزیہ کا ڈھانچہ تشکیل دیا جا سکے۔ اس کی معلوماتی کارکردگی کا تجربہ چین کے صوبہ سیچوان میں 2749 بسز پر مشتمل بجلی کے نظام کے ذریعے میدان میں کیا گیا۔ نتائج سے ظاہر ہوتا ہے کہ پیش کردہ EMS معلوماتی کارکردگی میں نمایاں اضافہ کرتا ہے اور حقیقی وقت میں بجلی کے نظام کے تجزیہ کے مقصد کو حاصل کرتا ہے۔
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ur
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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).
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Şu anda CERN'de yapılan charmon dinamikleri ve hadron kolektif akışı deneylerinin durumu eleştirel bir şekilde tartışılıyor. 1 ile 50 A$\cdot$GeV arasındaki akış uyarım fonksiyonunun önemine vurgu yapılıyor: hidrodinamik model, $v_1$-akışının ve $v_2$-akışının yaklaşık 10 A$\cdot$GeV'de çökmesini öngörmüştü; bu çökme yaklaşık 40 A$\cdot$GeV'de yakın zamanda NA49 işbirliği tarafından gözlemlendi. Hadronik yeniden saçılma modelleri bu enerjide gözlemlenen akıştan çok daha büyük akış öngördüğü için, bu gözlemi yüksek baryon yoğunluğu $\rho_B$'da birinci dereceden bir faz geçişinin olası kanıtı olarak yorumluyoruz. Daha sonra RHIC'te sıcak ve yoğun maddenin hal denklemi (EoS) için bir barometre olarak kolektif akış ayrıntılı biçimde tartışılıyor. Ayrıca ayrıntılı taşıma çalışmaları, karşıt taraftaki jet baskılanmasının yalnızca kısmen (< %50) hadronik yeniden saçılma nedeniyle olabileceğini gösteriyor. Son olarak, bozunum bölgesinde, yani $\mu_B \approx 400$ MeV ($y \approx 4-5$) civarında, 40 A$\cdot$GeV verilerinde olduğu gibi proton akışının çökmesinin gözleneceği, birinci dereceden faz geçişini inceleyecek RHIC'te iyileştirmeler ve ikinci nesil deneyler öneriyoruz. RHIC'te oluşan Kuark Gluon Plazmasında (QGP) jetlerin oluşturduğu Jet-Uyanık-Potansiyellerin ve Püskürtme Şoklarının incelenmesi, Kuark Gluon Plazmasının (QGP) hal denklemi (EoS) ve taşıma katsayıları hakkında ek bilgi sağlayabilir.
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tr
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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.
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Sebuah publikasi terbaru menyajikan grafik jaringan untuk mikrosirkuit neokortikal yang terdiri dari 8 juta koneksi antara 31.000 neuron (H. Markram, dkk., Rekonstruksi dan simulasi mikrosirkuit neokortikal, Cell, 163 (2015) no. 2, 456-492). Karena metode teori grafik tradisional mungkin tidak cukup untuk memahami kompleksitas luar biasa dari jaringan biologis semacam ini, kami mengeksplorasi apakah metode dari topologi aljabar dapat memberikan perspektif baru terhadap organisasi struktural dan fungsionalnya. Analisis topologis struktural mengungkapkan bahwa grafik terarah yang merepresentasikan konektivitas antar neuron dalam mikrosirkuit menyimpang secara signifikan dari berbagai jenis grafik acak. Secara khusus, grafik terarah tersebut mengandung sekitar $10^7$ simplices {\DH} kelompok neuron dengan konektivitas terarah semua-ke-semua. Beberapa simplices ini mengandung hingga 8 neuron, menjadikannya motif pengelompokan neuron paling ekstrem yang pernah dilaporkan. Analisis topologis fungsional terhadap aktivitas neuron yang disimulasikan dalam mikrosirkuit mengungkap metrik spasial-temporal yang baru dan mampu mengklasifikasikan secara efektif respons fungsional terhadap rangsangan yang secara kualitatif berbeda. Penelitian ini merupakan analisis topologi aljabar pertama terhadap konektomika struktural dan aktivitas spasial-temporal berbasis konektomika dalam mikrosirkuit saraf yang realistis secara biologis. Metode yang digunakan dalam penelitian ini menunjukkan potensi untuk aplikasi yang lebih luas dalam ilmu jaringan.
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id
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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.
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পরবর্তী প্রজন্মের মহাজাগতিক মাইক্রোতরঙ্গ পটভূমি (সিএমবি) পরীক্ষাগুলির মধ্যে একটি প্রধান লক্ষ্য হল প্রাথমিক বি-মোড সংকেতের সনাক্তকরণ। চতুর্থ পর্যায়ের পরীক্ষার জন্য পরিকল্পনা চলছে যা এমন যন্ত্রের শব্দ থাকার কথা যা যথেষ্ট ক্ষুদ্র হবে, যাতে বহুমুখীকরণ এবং পূর্বভাগীয় উপাদানগুলিকে টেন্সর-টু-স্কেলার অনুপাত $r$ অনুমানের জন্য প্রধান অনিশ্চয়তার উৎস হিসাবে প্রতিষ্ঠিত করা যায় যা ধ্রুবীকরণ মানচিত্র থেকে পাওয়া যায়। এটি ভবিষ্যতের সিএমবি ধ্রুবীকরণ বিজ্ঞানের জন্য বহুমুখীকরণ অপসারণকে অত্যন্ত গুরুত্বপূর্ণ করে তোলে। এই প্রবন্ধে, আমরা সিএমবি ধ্রুবীকরণ পর্যবেক্ষণ থেকে টেন্সর-টু-স্কেলার অনুপাত $r$ অনুমানের জন্য একটি সম্ভাব্যতা পদ্ধতি উপস্থাপন করি, যা কোয়াড্র্যাটিক বহুমুখীকরণ অপসারণ কৌশলের বাস্তবায়নের সুবিধার সাথে একটি পূর্ণাঙ্গ সম্ভাব্যতা পদ্ধতির সুবিধাগুলি একত্রিত করে। এই পদ্ধতিটি কোয়াড্র্যাটিক বহুমুখীকরণ অপসারণ করা বি-মোডগুলির পিক্সেল স্থানের সমস্ত ক্রমের সম্ভাব্যতা বিশ্লেষণ এবং এটি মূলত কোয়াড্র্যাটিক বহুমুখীকরণ অপসারণকারীকে সমস্ত ক্রমের বহুমুখীকরণ এবং পিক্সেল স্থানের অস্বাভাবিকতা বিবেচনায় নেওয়ার মাধ্যমে গঠিত। এর বাস্তবায়নের উপর নির্ভরশীল একটি গুরুত্বপূর্ণ বিষয় হল ধ্রুবীকরণ পর্যবেক্ষণের পিক্সেল স্থানের ভেদাঙ্ক ম্যাট্রিক্সের একটি গুণন, যা একক সম্ভাব্যতা মূল্যায়নের সমান গাণিতিক খরচে $r$-এর ফাংশন হিসাবে পূর্ণ গাউসীয় আসন্ন সম্ভাব্যতা প্রোফাইল গণনা করার অনুমতি দেয়।
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bn
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An interpretable system for open-domain reasoning needs to express its reasoning process in a transparent form. Natural language is an attractive representation for this purpose -- it is both highly expressive and easy for humans to understand. However, manipulating natural language statements in logically consistent ways is hard: models must cope with variation in how meaning is expressed while remaining precise. In this paper, we describe ParaPattern, a method for building models to generate deductive inferences from diverse natural language inputs without direct human supervision. We train BART-based models (Lewis et al., 2020) to generate the result of applying a particular logical operation to one or more premise statements. Crucially, we develop a largely automated pipeline for constructing suitable training examples from Wikipedia. We evaluate our models using out-of-domain sentence compositions from the QASC (Khot et al., 2020) and EntailmentBank (Dalvi et al., 2021) datasets as well as targeted perturbation sets. Our results show that our models are substantially more accurate and flexible than baseline systems. ParaPattern achieves 85% validity on examples of the 'substitution' operation from EntailmentBank without the use of any in-domain training data, matching the performance of a model fine-tuned for EntailmentBank. The full source code for our method is publicly available.
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کھلے شعبے کے استدلال کے لیے ایک تشریح کی جا سکنے والی نظام کو اپنے استدلال کے عمل کو شفاف شکل میں ظاہر کرنے کی ضرورت ہوتی ہے۔ اس مقصد کے لیے قدرتی زبان ایک پرکشش نمائندگی ہے -- یہ نہ صرف انتہائی اظہاری ہوتی ہے بلکہ انسانوں کے لیے سمجھنا بھی آسان ہوتی ہے۔ تاہم، قدرتی زبان کے بیانات کو منطقی طور پر مسلّط انداز میں استعمال کرنا مشکل ہوتا ہے: ماڈلز کو معنی کے اظہار میں ہونے والی تنوع کا سامنا کرتے ہوئے بھی درست رہنا ہوتا ہے۔ اس مقالے میں، ہم پیراپیٹرن کا تفصیلی جائزہ پیش کرتے ہیں، جو براہ راست انسانی نگرانی کے بغیر مختلف قدرتی زبان کے ادخالات سے منطقی نتائج اخذ کرنے والے ماڈلز تیار کرنے کا ایک طریقہ ہے۔ ہم بارٹ پر مبنی ماڈلز (لیوس و دیگر، 2020) کو ایک یا ایک سے زیادہ اصل بیانات پر ایک خاص منطقی عمل کو لاگو کرنے کا نتیجہ پیدا کرنے کے لیے تربیت دیتے ہیں۔ اہم بات یہ ہے کہ ہم ویکیپیڈیا سے مناسب تربیت کے مثالوں کی تعمیر کے لیے ایک زیادہ تر خودکار پائپ لائن تیار کرتے ہیں۔ ہم اپنے ماڈلز کا اطلاق QASC (کھوت و دیگر، 2020) اور انٹیلمنٹ بینک (دلّوی و دیگر، 2021) ڈیٹا سیٹس سے خارجِ شعبہ جملوں کی تشکیل کے علاوہ ہدف بنائے گئے تغیرات کے سیٹس کے ذریعے جانچتے ہیں۔ ہمارے نتائج ظاہر کرتے ہیں کہ ہمارے ماڈلز بنیادی نظاموں کے مقابلے میں کافی زیادہ درست اور لچکدار ہیں۔ پیراپیٹرن بغیر کسی داخلِ شعبہ تربیتی ڈیٹا کے انٹیلمنٹ بینک کے 'تبدیلی' کے عمل کی مثالوں پر 85 فیصد درستگی حاصل کرتا ہے، جو انٹیلمنٹ بینک کے لیے مخصوص طور پر فائن ٹیون کیے گئے ماڈل کی کارکردگی کے برابر ہے۔ ہمارے طریقہ کا مکمل سورس کوڈ عوامی طور پر دستیاب ہے۔
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ur
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New algorithms for efficient decoding of polar codes (which may be CRC-augmented), transmitted over either a binary erasure channel (BEC) or an additive white Gaussian noise channel (AWGNC), are presented. We start by presenting a new efficient exact maximum likelihood decoding algorithm for the BEC based on inactivation decoding and analyze its computational complexity. This algorithm applies a matrix triangulation process on a sparse polar code parity check matrix, followed by solving a small size linear system over GF(2). We then consider efficient decoding of polar codes, transmitted over the AWGNC. The algorithm applies CRC-aided belief propagation list (CBPL) decoding, followed by ordered statistics decoding (OSD) of low order. Even when the reprocessing order of the OSD is as low as one, the new decoder is shown to significantly improve on plain CBPL. To implement the OSD efficiently, we adapt the matrix triangulation algorithm from the BEC case. We also indicate how the decoding algorithms can be implemented in parallel for low latency decoding. Numerical simulations are used to evaluate the performance and computational complexity of the new algorithms.
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ပေါလာကုဒ်များ (CRC ဖြင့် တိုးချဲ့ထားနိုင်သည်) ကို ဒွိဖျက်သိမ်းရေးချိန် (BEC) သို့မဟုတ် ထည့်သွင်းအသုံးပြုသည့် အဖြူရောင်ဂေါ့စီယန်း အသံဆူညံမှု ချိန် (AWGNC) တို့ပေါ်တွင် ထုတ်လွှတ်သည့်အခါ ထိရောက်စွာ ဒီကုဒ်ဖြေရန် အတွက် အယ်လ်ဂိုရီသမ်များကို တင်ပြသည်။ အင်အားကောင်းသော မဟုတ်ပါက ဒီကုဒ်ဖြေခြင်းအတွက် အသစ်ဖြစ်ပြီး ထိရောက်သော တိကျသည့် အများဆုံးဖြစ်နိုင်ခြေ ဒီကုဒ်ဖြေခြင်း အယ်လ်ဂိုရီသမ်ကို မိတ်ဆက်ပြီး ၎င်း၏ တွက်ချက်မှု ရှုပ်ထွေးမှုကို ဆန်းစစ်သည်။ ဤအယ်လ်ဂိုရီသမ်သည် ပေါလာကုဒ်၏ မျှော်လင့်ချက်စစ်ဆေးမှု မက်ထရစ် တစ်ခုကို အသုံးပြု၍ မက်ထရစ် တြိဂံဖြစ်အောင် လုပ်ပြီးနောက် GF(2) အပေါ်တွင် အရွယ်အစားသေးငယ်သော လီနီယာစနစ်ကို ဖြေရှင်းခြင်းဖြစ်သည်။ ထို့နောက် AWGNC ပေါ်တွင် ထုတ်လွှတ်သည့် ပေါလာကုဒ်များ၏ ထိရောက်သော ဒီကုဒ်ဖြေခြင်းကို စဉ်းစားသည်။ အယ်လ်ဂိုရီသမ်သည် CRC ကူညီသော ယုံကြည်မှု ပျံ့နှံ့မှု စာရင်း (CBPL) ဒီကုဒ်ဖြေခြင်းကို အသုံးပြုပြီး နိမ့်ကျသော အဆင့်အတန်း စီထားသည့် စာရင်းဒီကုဒ်ဖြေခြင်း (OSD) ကို ဆက်လက်အသုံးပြုသည်။ OSD ၏ ပြန်လည်လုပ်ဆောင်မှု အဆင့်သည် တစ်ခုသာဖြစ်သော်လည်း အသစ်သော ဒီကုဒ်ဖြေစက်သည် ရိုးရိုး CBPL ကို သိသိသာသာ မြှင့်တင်ပေးကြောင်း ပြသထားသည်။ OSD ကို ထိရောက်စွာ အကောင်အထည်ဖော်ရန်အတွက် BEC အခြေအနေမှ မက်ထရစ် တြိဂံဖြစ်အောင်လုပ်သည့် အယ်လ်ဂိုရီသမ်ကို အသုံးပြုပြောင်းလဲသည်။ နိမ့်ကျသော နှောင့်နှေးမှု ဒီကုဒ်ဖြေခြင်းအတွက် ဒီကုဒ်ဖြေခြင်း အယ်လ်ဂိုရီသမ်များကို အပြိုင်အလုံးစုံ အကောင်အထည်ဖော်နိုင်ကြောင်းကိုလည်း ညွှန်ပြသည်။ အသစ်သော အယ်လ်ဂိုရီသမ်များ၏ စွမ်းဆောင်ရည်နှင့် တွက်ချက်မှု ရှုပ်ထွေးမှုကို အကဲဖြတ်ရန် ကိန်းဂဏန်း စမ်းသပ်မှုများကို အသုံးပြုသည်။
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my
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A phenomenological analysis of lifetimes of bottom and charmed hadrons within the framework of the heavy quark expansion is performed. The baryon matrix element is evaluated using the bag model and the nonrelativistic quark model. We find that bottom-baryon lifetimes follow the pattern $\tau(\Omega_b)\simeq\tau(\Xi_b^-)>\tau(\Lambda_b)\simeq\tau(\Xi_b^0)$. However, neither the lifetime ratio $\tau(\Lambda_b)/\tau( B_d)$ nor the absolute decay rates of the $\Lambda_b$ baryon and $B$ mesons can be explained. One way of solving both difficulties is to allow the presence of linear $1/m_Q$ corrections by scaling the inclusive nonleptonic width with the fifth power of the hadron mass $m_{H_Q}$ rather than the heavy quark mass $m_Q$. The hierarchy of bottom baryon lifetimes is dramatically modified to $\tau(\Lambda_b)>\tau(\Xi_b^-)>\tau(\Xi_b^0)>\tau( \Omega_b)$: The longest-lived $\Omega_b$ among bottom baryons in the OPE prescription now becomes shortest-lived. The replacement of $m_Q$ by $m_{H_Q}$ in nonleptonic widths is natural and justified in the PQCD-based factorization approach formulated in terms of hadron-level kinematics. For inclusive charmed baryon decays, we argue that since the heavy quark expansion does not converge, local duality cannot be tested in this case. We show that while the ansatz of substituting the heavy quark mass by the hadron mass provides a much better description of the charmed-baryon lifetime {\it ratios}, it appears unnatural and unpredictive for describing the {\it absolute} inclusive decay rates of charmed baryons, contrary to the bottom case.
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在重夸克展开的框架内，对底夸克和粲夸克强子的寿命进行了唯象分析。重子矩阵元通过袋模型和非相对论夸克模型进行计算。我们发现，底重子寿命呈现出 $\tau(\Omega_b)\simeq\tau(\Xi_b^-)>\tau(\Lambda_b)\simeq\tau(\Xi_b^0)$ 的模式。然而，无论是 $\tau(\Lambda_b)/\tau( B_d)$ 的寿命比，还是 $\Lambda_b$ 重子与 $B$ 介子的绝对衰变率，都无法得到解释。解决这两个困难的一种方法是引入线性的 $1/m_Q$ 修正项，即在非轻子衰变宽度中使用强子质量 $m_{H_Q}$ 的五次方代替重夸克质量 $m_Q$ 进行标度。这一修正显著改变了底重子寿命的层级关系，变为 $\tau(\Lambda_b)>\tau(\Xi_b^-)>\tau(\Xi_b^0)>\tau( \Omega_b)$：在OPE方案中原先寿命最长的 $\Omega_b$ 底重子，现在变为寿命最短的。在基于PQCD的因子化方法中，以强子层次运动学表述时，将非轻子衰变宽度中的 $m_Q$ 替换为 $m_{H_Q}$ 是自然且合理的。对于包含粲重子的衰变，我们认为由于重夸克展开在此情况下不收敛，因而无法检验局域对偶性。我们指出，尽管用强子质量替代重夸克质量的假设能更好地描述粲重子寿命的比值，但与底夸克情况相反，这种方法在描述粲重子包含衰变的绝对衰变率时显得不自然且缺乏预测能力。
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zh
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We present ALMA and ACA [CI]$^{3}P_{1}-^{3}P_{0}$ ([CI](1-0)) observations of NGC6240, which we combine with ALMA CO(2-1) and IRAM PdBI CO(1-0) data to study the physical properties of the massive molecular (H$_2$) outflow. We discover that the receding and approaching sides of the H$_2$ outflow, aligned east-west, exceed 10 kpc in their total extent. High resolution ($0.24"$) [CI](1-0) line images surprisingly reveal that the outflow emission peaks between the two AGNs, rather than on either of the two, and that it dominates the velocity field in this nuclear region. We combine the [CI](1-0) and CO(1-0) data to constrain the CO-to-H$_2$ conversion factor ($\alpha_{\rm CO}$) in the outflow, which is on average $2.1\pm1.2~\rm M_{\odot} (K~km~s^{-1}~pc^2)^{-1}$. We estimate that $60\pm20$ % of the total H$_2$ gas reservoir of NGC6240 is entrained in the outflow, for a resulting mass-loss rate of $\dot{M}_{\rm out}=2500\pm1200~M_{\odot}~yr^{-1}$ $\equiv 50\pm30$ SFR. This energetics rules out a solely star formation-driven wind, but the puzzling morphology challenges a classic radiative-mode AGN feedback scenario. For the quiescent gas we compute $\langle\alpha_{\rm CO}\rangle = 3.2\pm1.8~\rm M_{\odot} (K~km~s^{-1}~pc^2)^{-1}$, which is at least twice the value commonly employed for (U)LIRGs. We observe a tentative trend of increasing $r_{21}\equiv L^{\prime}_{\rm CO(2-1)}/L^{\prime}_{\rm CO(1-0)}$ ratios with velocity dispersion and measure $r_{21}>1$ in the outflow, whereas $r_{21}\simeq1$ in the quiescent gas. We propose that molecular outflows are the location of the warmer, strongly unbound phase that partially reduces the opacity of the CO lines in (U)LIRGs, hence driving down their global $\alpha_{\rm CO}$ and increasing their $r_{21}$ values.
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Presentiamo osservazioni ALMA e ACA della transizione [CI]$^{3}P_{1}-^{3}P_{0}$ ([CI](1-0)) di NGC6240, che combiniamo con dati ALMA della linea CO(2-1) e dati IRAM PdBI della linea CO(1-0) per studiare le proprietà fisiche dell'outflow molecolare massiccio (H$_2$). Scopriamo che i lati in recessione e in avvicinamento dell'outflow di H$_2$, allineati est-ovest, superano complessivamente un'estensione di 10 kpc. Immagini ad alta risoluzione ($0.24"$) della linea [CI](1-0) rivelano in modo sorprendente che l'emissione dell'outflow presenta un massimo tra i due AGN, piuttosto che su uno dei due, e che domina il campo di velocità in questa regione nucleare. Combiniamo i dati [CI](1-0) e CO(1-0) per vincolare il fattore di conversione da CO ad H$_2$ ($\alpha_{\rm CO}$) nell'outflow, il cui valore medio è $2.1\pm1.2~\rm M_{\odot} (K~km~s^{-1}~pc^2)^{-1}$. Stimiamo che il $60\pm20$ % dell'intero serbatoio di gas H$_2$ di NGC6240 sia coinvolto nell'outflow, con un tasso di perdita di massa risultante di $\dot{M}_{\rm out}=2500\pm1200~M_{\odot}~yr^{-1}$ $\equiv 50\pm30$ SFR. Questa energetica esclude un vento generato esclusivamente dalla formazione stellare, ma la morfologia enigmatica contrasta con uno scenario classico di retroazione AGN in modalità radiativa. Per il gas tranquillo calcoliamo $\langle\alpha_{\rm CO}\rangle = 3.2\pm1.8~\rm M_{\odot} (K~km~s^{-1}~pc^2)^{-1}$, valore almeno doppio rispetto a quello comunemente utilizzato per le (U)LIRG. Osserviamo una tendenza indicativa di aumenti del rapporto $r_{21}\equiv L^{\prime}_{\rm CO(2-1)}/L^{\prime}_{\rm CO(1-0)}$ con la dispersione di velocità e misuriamo $r_{21}>1$ nell'outflow, mentre $r_{21}\simeq1$ nel gas tranquillo. Proponiamo che gli outflow molecolari siano la sede della fase più calda e fortemente non legata che riduce parzialmente l'opacità delle linee CO nelle (U)LIRG, determinando così una diminuzione del loro $\alpha_{\rm CO}$ globale e un aumento dei valori di $r_{21}$.
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it
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We show that typical behaviors of market participants at the high frequency scale generate leverage effect and rough volatility. To do so, we build a simple microscopic model for the price of an asset based on Hawkes processes. We encode in this model some of the main features of market microstructure in the context of high frequency trading: high degree of endogeneity of market, no-arbitrage property, buying/selling asymmetry and presence of metaorders. We prove that when the first three of these stylized facts are considered within the framework of our microscopic model, it behaves in the long run as a Heston stochastic volatility model, where leverage effect is generated. Adding the last property enables us to obtain a rough Heston model in the limit, exhibiting both leverage effect and rough volatility. Hence we show that at least part of the foundations of leverage effect and rough volatility can be found in the microstructure of the asset.
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আমরা দেখাই যে উচ্চ ফ্রিকোয়েন্সি স্কেলে বাজারের অংশগ্রহণকারীদের সাধারণ আচরণ লিভারেজ প্রভাব এবং রাফ অস্থিরতা তৈরি করে। এটি করার জন্য, আমরা হকস প্রক্রিয়ার উপর ভিত্তি করে একটি সম্পদের দামের জন্য একটি সাধারণ সূক্ষ্ম মডেল তৈরি করি। উচ্চ ফ্রিকোয়েন্সি ট্রেডিংয়ের প্রেক্ষাপটে বাজারের সূক্ষ্ম কাঠামোর কিছু প্রধান বৈশিষ্ট্য আমরা এই মডেলে অন্তর্ভুক্ত করি: বাজারের উচ্চ মাত্রার অন্তর্জাতিকতা, নো-আরবিট্রাজ বৈশিষ্ট্য, ক্রয়/বিক্রয় অসমতা এবং মেটাঅর্ডারের উপস্থিতি। আমরা প্রমাণ করি যে যখন এই ধরনের স্টাইলাইজড তথ্যগুলির প্রথম তিনটি আমাদের সূক্ষ্ম মডেলের কাঠামোতে বিবেচনা করা হয়, তখন দীর্ঘমেয়াদে এটি একটি হেস্টন স্টোকাস্টিক ভলাটিলিটি মডেলের মতো আচরণ করে, যেখানে লিভারেজ প্রভাব তৈরি হয়। শেষ বৈশিষ্ট্যটি যোগ করলে আমরা সীমাতে একটি রাফ হেস্টন মডেল পাই, যেখানে লিভারেজ প্রভাব এবং রাফ অস্থিরতা উভয়ই দেখা যায়। তাই আমরা দেখাই যে লিভারেজ প্রভাব এবং রাফ অস্থিরতার অন্তত অংশবিশেষের ভিত্তি সম্পদের সূক্ষ্ম কাঠামোতে পাওয়া যায়।
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bn
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We present a new family of zero-field Ising models over $N$ binary variables/spins obtained by consecutive "gluing" of planar and $O(1)$-sized components and subsets of at most three vertices into a tree. The polynomial-time algorithm of the dynamic programming type for solving exact inference (computing partition function) and exact sampling (generating i.i.d. samples) consists in a sequential application of an efficient (for planar) or brute-force (for $O(1)$-sized) inference and sampling to the components as a black box. To illustrate the utility of the new family of tractable graphical models, we first build a polynomial algorithm for inference and sampling of zero-field Ising models over $K_{3,3}$-minor-free topologies and over $K_{5}$-minor-free topologies -- both are extensions of the planar zero-field Ising models -- which are neither genus - nor treewidth-bounded. Second, we demonstrate empirically an improvement in the approximation quality of the NP-hard problem of inference over the square-grid Ising model in a node-dependent non-zero "magnetic" field.
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เราเสนอตระกูลใหม่ของโมเดลไอซิงแบบสนามศูนย์ (zero-field Ising models) ที่มีตัวแปร/สปินแบบไบนารีจำนวน $N$ ตัว ซึ่งได้มาจากการ "ต่อกัน" อย่างต่อเนื่องขององค์ประกอบที่มีลักษณะระนาบและองค์ประกอบขนาด $O(1)$ รวมถึงชุดย่อยที่มีจุดสุดยอดไม่เกินสามจุดเข้าด้วยกันในรูปแบบต้นไม้ อัลกอริธึมแบบพหุนามที่ใช้การเขียนโปรแกรมแบบพลวัต (dynamic programming) สำหรับการอนุมานแบบแม่นยำ (การคำนวณฟังก์ชันพาร์ติชัน) และการสุ่มตัวอย่างแบบแม่นยำ (การสร้างตัวอย่างที่เป็นอิสระและเหมือนกัน) ประกอบด้วยการประยุกต์ใช้ขั้นตอนวิธีการอนุมานและการสุ่มตัวอย่างที่มีประสิทธิภาพ (สำหรับกรณีระนาบ) หรือแบบแรงดิบ (brute-force) (สำหรับกรณีขนาด $O(1)$) กับแต่ละองค์ประกอบอย่างต่อเนื่อง โดยถือองค์ประกอบเหล่านั้นเป็นกล่องดำ (black box) เพื่อแสดงให้เห็นถึงประโยชน์ของตระกูลโมเดลเชิงกราฟที่สามารถจัดการได้นี้ เราได้สร้างอัลกอริธึมแบบพหุนามสำหรับการอนุมานและการสุ่มตัวอย่างของโมเดลไอซิงแบบสนามศูนย์บนโครงสร้างที่ไม่มีไมเนอร์ $K_{3,3}$ และบนโครงสร้างที่ไม่มีไมเนอร์ $K_{5}$ ซึ่งทั้งสองกรณีเป็นการขยายจากโมเดลไอซิงแบบสนามศูนย์ที่มีลักษณะระนาบ โดยโครงสร้างดังกล่าวไม่อยู่ในขอบเขตที่จำกัดด้วยพันธุกรรม (genus) หรือความกว้างของต้นไม้ (treewidth) ต่อมา เราได้แสดงให้เห็นโดยการทดลองถึงการปรับปรุงคุณภาพของการประมาณผลสำหรับปัญหาการอนุมานซึ่งเป็นปัญหาแบบ NP-hard บนโมเดลไอซิงที่มีโครงข่ายรูปสี่เหลี่ยมจัตุรัสภายใต้สนาม "แม่เหล็ก" ที่ไม่เป็นศูนย์และขึ้นอยู่กับโหนด
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th
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We develop a robust coarse-grained model for single and double stranded DNA by representing each nucleotide by three interaction sites (TIS) located at the centers of mass of sugar, phosphate, and base. The resulting TIS model includes base-stacking, hydrogen bond, and electrostatic interactions as well as bond-stretching and bond angle potentials that account for the polymeric nature of DNA. The choices of force constants for stretching and the bending potentials were guided by a Boltzmann inversion procedure using a large representative set of DNA structures extracted from the Protein Data Bank. Some of the parameters in the stacking interactions were calculated using a learning procedure, which ensured that the experimentally measured melting temperatures of dimers are faithfully reproduced. Without any further adjustments, the calculations based on the TIS model reproduces the experimentally measured salt and sequence dependence of the size of single stranded DNA (ssDNA), as well as the persistence lengths of poly(dA) and poly(dT) chains. Interestingly, upon application of mechanical force the extension of poly(dA) exhibits a plateau, which we trace to the formation of stacked helical domains. In contrast, the force-extension curve (FEC) of poly(dT) is entropic in origin, and could be described by a standard polymer model. We also show that the persistence length of double stranded DNA is consistent with the prediction based on the worm-like chain. The persistence length, which decreases with increasing salt concentration, is in accord with the Odijk-Skolnick-Fixman theory intended for stiff polyelectrolyte chains near the rod limit. The range of applications, which did not require adjusting any parameter after the initial construction based solely on PDB structures and melting profiles of dimers, attests to the transferability and robustness of the TIS model for ssDNA and dsDNA.
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Tek ve çift iplikli DNA için, her nükleotidi şeker, fosfat ve bazın kütle merkezlerinde yer alan üç etkileşim bölgesiyle (TIS) temsil ederek sağlam bir kaba tanecikli model geliştiriyoruz. Elde edilen TIS modeli, DNA'nın polimerik yapısını hesaba katan bağ uzama ve bağ açısı potansiyellerinin yanı sıra, baz yığılma, hidrojen bağı ve elektrostatik etkileşimleri de içerir. Uzama ve bükülme potansiyelleri için seçilen kuvvet sabitleri, Protein Veri Bankası'ndan çıkarılan büyük bir temsili DNA yapı seti kullanılarak Boltzmann tersine çevrim yöntemiyle belirlenmiştir. Yığılma etkileşimlerindeki bazı parametreler, dimerlerin deneysel olarak ölçülen erime sıcaklıklarının doğru bir şekilde yeniden üretildiğini garanti eden bir öğrenme yöntemiyle hesaplanmıştır. Herhangi bir ek ayarlamaya gerek kalmadan, TIS modeline dayalı hesaplamalar, tek iplikli DNA'nın (ssDNA) boyutunun tuz ve dizi bağımlılığını deneysel olarak ölçülen değerlerle uyumlu şekilde yeniden üretir. Ayrıca, poli(dA) ve poli(dT) zincirlerinin kırılma uzunlukları da doğru şekilde verilir. İlginç bir şekilde, mekanik kuvvet uygulandığında poli(dA)'nın uzaması bir plaто gösterir ve bu durumu yığılmış heliks alanlarının oluşumuna bağlarız. Buna karşılık, poli(dT)'nin kuvvet-uzama eğrisi (FEC) entropik kökenlidir ve standart bir polimer modeliyle tanımlanabilir. Ayrıca, çift iplikli DNA'nın kırılma uzunluğunun solucan-benzeri zincir modelinin öngörüsüyle tutarlı olduğunu gösteriyoruz. Tuz konsantrasyonu arttıkça azalan kırılma uzunluğu, çubuk sınırına yakın sert polielektrolit zincirler için tasarlanan Odijk-Skolnick-Fixman teorisiyle uyumludur. Modelin uygulama alanları, başlangıçta yalnızca PDB yapıları ve dimerlerin erime profilleri temel alınarak oluşturulduktan sonra herhangi bir parametrenin ayarlanmamasına rağmen geniş bir başarım sergilemiş olup, TIS modelinin ssDNA ve dsDNA için taşıyabilirliğini ve sağlam yapısını kanıtlamaktadır.
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tr
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Pyrochlore systems ($A_{2}B_{2}O_{7}$) with $A$-site rare-earth local moments and $B$-site $5d$ conduction electrons offer excellent material platforms for the discovery of exotic quantum many-body ground states. Notable examples include U(1) quantum spin liquid of the local moments and semimetallic non-Fermi liquid of the conduction electrons. Here we investigate emergent quantum phases and their transitions driven by the Kondo lattice coupling between such highly entangled quantum ground states. Using the renormalization group method, it is shown that weak Kondo lattice coupling is irrelevant, leading to a fractionalized semimetal phase with decoupled local moments and conduction electrons. Upon increasing the Kondo lattice coupling, this phase is unstable to the formation of broken symmetry states. Particularly important is the opposing influence of the Kondo lattice coupling and long-range Coulomb interaction. The former prefers to break the particle-hole symmetry while the latter tends to restore it. The characteristic competition leads to possibly multiple phase transitions, first from a fractionalized semimetal phase to a fractionalized Fermi surface state with particle-hole pockets, followed by the second transition to a fractionalized ferromagnetic state. Multiscale quantum critical behaviors appear at nonzero temperatures and with external magnetic field near such quantum phase transitions. We discuss the implication of these results to the experiments on Pr$_2$Ir$_2$O$_7$.
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Пирохлорные системы ($A_{2}B_{2}O_{7}$) с локальными магнитными моментами редкоземельных элементов на позициях $A$ и проводящими электронами $5d$ на позициях $B$ представляют собой превосходные материальные платформы для обнаружения экзотических квантовых многотельных основных состояний. Среди примечательных примеров — спиновая жидкость с симметрией U(1) локальных моментов и полуметаллическая неФерми-жидкость проводящих электронов. В данной работе мы исследуем возникающие квантовые фазы и их переходы, вызванные решётчатой связью Кондо между такими сильно запутанными квантовыми основными состояниями. С помощью метода ренормгруппы показано, что слабая решётчатая связь Кондо является нерелевантной, что приводит к фракционализованной полуметаллической фазе с разъединёнными локальными моментами и проводящими электронами. При увеличении решётчатой связи Кондо эта фаза становится неустойчивой по отношению к образованию состояний с нарушенной симметрией. Особую важность представляет противоположное влияние решётчатой связи Кондо и дальнодействующего кулоновского взаимодействия. Первое стремится нарушить симметрию частица-дырка, в то время как второе, напротив, стремится восстановить её. Характерная конкуренция приводит к возможному наличию нескольких фазовых переходов: сначала от фракционализованной полуметаллической фазы к состоянию с фракционализованной ферми-поверхностью, содержащей карманы частиц и дырок, а затем ко второму переходу — в фракционализованное ферромагнитное состояние. Многошкальное квантовое критическое поведение проявляется при ненулевых температурах и во внешнем магнитном поле вблизи таких квантовых фазовых переходов. Обсуждаются последствия полученных результатов для экспериментов на Pr$_2$Ir$_2$O$_7$.
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ru
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We study quantum correlations and discord in a bipartite continuous variable hybrid system formed by linear combinations of coherent states $|\alpha\rangle$ and single photon added coherent states (SPACS) of the form $|\psi\rangle_{\text{dp(pa)}}= \mathcal{N}/\sqrt{2} (\hat{a}^\dagger |\alpha\rangle_a |\alpha\rangle_b \pm \hat{b}^\dagger |\alpha\rangle_a |\alpha\rangle_b)$. We stablish a relationship between the quantum discord with a local observable (the quadrature variance for one sub-system) under the influence of scattering and phase fluctuation noise. For the pure states the quantum correlations are characterized by means of measurement induced disturbance (MID) with simultaneous quadrature measurements. In a scenario where homodyne conditional measurements are available we show that the MID provides an easy way to select optimal phases to obtain information of the maximal correlations in the channels. The quantum correlations of these entangled states with channel losses are quantitatively characterized with the quantum discord (QD) with a displaced qubit projector. We observe that as scattering increases, QD decreases monotonically. At the same time for the state $|\psi\rangle_{\text{dp}}$, QD is more resistant to high phase fluctuations when the average photon number $n_0$ is bigger than zero, but if phase fluctuations are low, QD is more resistant if $n_0=0$. For the dp model with scattering, we obtain an analytical expression of the QD as a function of the observable quadrature variance in a local sub-system. This relation allows us to have a way to obtain the degree of QD in the channel by just measuring a local property observable such as the quadrature variance. For the other model this relation still exists but is explored numerically. This relation is an important result that allows to identify quantum processing capabilities in terms of just local observables.
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Studujeme kvantové korelace a diskord v bipartitním hybridním systému s nepřetržitými proměnnými, který je tvořen lineárními kombinacemi koherentních stavů $|\alpha\rangle$ a koherentních stavů s přidaným jedním fotonem (SPACS) ve tvaru $|\psi\rangle_{\text{dp(pa)}}= \mathcal{N}/\sqrt{2} (\hat{a}^\dagger |\alpha\rangle_a |\alpha\rangle_b \pm \hat{b}^\dagger |\alpha\rangle_a |\alpha\rangle_b)$. Stanovíme vztah mezi kvantovým diskordem a lokální pozorovatelnou veličinou (rozptylem kvadratury pro jeden podsystém) za přítomnosti šumu způsobeného rozptylem a fluktuacemi fáze. Pro čisté stavy jsou kvantové korelace charakterizovány pomocí poruchy vyvolané měřením (MID) při současných měřeních kvadratur. Ve scénáři, kdy jsou k dispozici homodyně podmíněná měření, ukazujeme, že MID poskytuje jednoduchý způsob výběru optimálních fází pro získání informace o maximálních korelacích v kanálech. Kvantové korelace těchto provázaných stavů za přítomnosti ztrát v kanále jsou kvantitativně charakterizovány kvantovým diskordem (QD) pomocí posunutého qubitového projektoru. Pozorujeme, že s rostoucím rozptylem QD monotónně klesá. Současně pro stav $|\psi\rangle_{\text{dp}}$ je QD odolnější vůči vysokým fázovým fluktuacím, když střední počet fotonů $n_0$ je větší než nula, ale pokud jsou fázové fluktuace nízké, je QD odolnější při $n_0=0$. Pro dp model s rozptylem získáme analytický výraz pro QD jako funkci pozorovatelného rozptylu kvadratury v lokálním podsystému. Tento vztah umožňuje určit míru QD v kanále pouhým měřením lokální pozorovatelné veličiny, jako je rozptyl kvadratury. Pro druhý model tento vztah rovněž existuje, ale je prozkoumán numericky. Tento vztah je důležitým výsledkem, který umožňuje identifikovat kvantové zpracovatelské schopnosti pouze na základě lokálních pozorovatelných veličin.
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cs
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We present a systematic derivation of a model based on the central moment lattice Boltzmann equation that rigorously maintains Galilean invariance of forces to simulate inertial frame independent flow fields. In this regard, the central moments, i.e. moments shifted by the local fluid velocity, of the discrete source terms of the lattice Boltzmann equation are obtained by matching those of the continuous full Boltzmann equation of various orders. This results in an exact hierarchical identity between the central moments of the source terms of a given order and the components of the central moments of the distribution functions and sources of lower orders. The corresponding source terms in velocity space are then obtained from an exact inverse transformation due to a suitable choice of orthogonal basis for moments. Furthermore, such a central moment based kinetic model is further extended by incorporating reduced compressibility effects to represent incompressible flow. Moreover, the description and simulation of fluid turbulence for full or any subset of scales or their averaged behavior should remain independent of any inertial frame of reference. Thus, based on the above formulation, a new approach in lattice Boltzmann framework to incorporate turbulence models for simulation of Galilean invariant statistical averaged or filtered turbulent fluid motion is discussed.
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Isinasalarawan namin ang isang sistematikong pagkuha ng isang modelo batay sa lattice Boltzmann equation na gumagamit ng central moment na mahigpit na nagpapanatili ng Galilean invariance ng mga puwersa upang masimulan ang mga field ng daloy na malaya sa inertial na balangkas. Sa ganitong pagtingin, ang mga central moment, iyon ay, mga moment na nailipat batay sa lokal na bilis ng likido, ng diskretong mga terminong pinagmulan ng lattice Boltzmann equation ay natutukoy sa pamamagitan ng pagtutugma sa mga katumbas nito mula sa tuloy-tuloy na buong Boltzmann equation sa iba't ibang mga order. Nagreresulta ito sa isang eksaktong hierarkikal na pagkakakilanlan sa pagitan ng mga central moment ng mga terminong pinagmulan sa isang partikular na order at ang mga bahagi ng mga central moment ng mga function ng pamamahagi at mga pinagmulan sa mas mababang order. Ang mga koresponding terminong pinagmulan sa espasyo ng bilis ay natutukoy naman sa pamamagitan ng isang eksaktong pagbabalik ng transpormasyon dahil sa angkop na pagpili ng orthogonal na basehan para sa mga moment. Higit pa rito, ang naturang modelo ng central moment na batay sa kinetic ay karagdagang pinapalawak sa pamamagitan ng pagsasama ng mga epekto ng nabawasang compressibility upang kumatawan sa daloy na hindi mapaparami. Bukod dito, ang paglalarawan at pagsimula ng turbulensiya ng likido para sa buong o anumang subset ng mga sukat o ang kanilang nai-averagyong pag-uugali ay dapat manatiling malaya sa anumang inertial na balangkas ng sanggunian. Samakatuwid, batay sa nabanggit na pormulasyon, isang bagong pamamaraan sa loob ng lattice Boltzmann framework upang isama ang mga modelo ng turbulensiya para sa pagsimula ng Galilean invariant na nai-averagyong estadistika o nafilter na turbulenteng kilusan ng likido ay talakayin.
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tl
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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%.
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Grandes quantidades de dados rotulados para treinamento são um dos principais fatores responsáveis pelo grande sucesso que os modelos profundos alcançaram no passado. A obtenção de rótulos para tarefas que não sejam benchmarks pode representar um desafio devido aos requisitos de financiamento e expertise. Ao selecionar exemplos não rotulados promissores em termos de melhoria do modelo e solicitar apenas os rótulos correspondentes, o aprendizado ativo pode aumentar a eficiência do processo de rotulagem em termos de tempo e custo. Neste trabalho, descrevemos combinações de um esquema de aprendizado incremental e métodos de aprendizado ativo. Essas combinações permitem a exploração contínua de novos dados não rotulados observados. Descrevemos critérios de seleção baseados na incerteza do modelo, bem como na mudança esperada na saída do modelo (EMOC). Uma tarefa de detecção de objetos é avaliada em um contexto de exploração contínua no conjunto de dados PASCAL VOC. Também validamos um sistema de supervisão fraca baseado em aprendizado ativo e incremental em uma aplicação real de biodiversidade, na qual imagens de armadilhas fotográficas são analisadas. Rotular apenas 32 imagens, aceitando ou rejeitando propostas geradas pelo nosso método, resulta em um aumento na precisão de 25,4% para 42,6%.
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pt
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Making use of both MUSE observations of 85 galaxies from the survey GASP (GAs Stripping Phenomena in galaxies with MUSE) and a large sample from MaNGA (Mapping Nearby Galaxies at Apache Point Observatory survey) we investigate the distribution of gas metallicity gradients as a function of stellar mass, for local cluster and field galaxies. Overall, metallicity profiles steepen with increasing stellar mass up to $10^{10.3}\,{\rm M_\odot}$ and flatten out at higher masses. Combining the results from the metallicity profiles and the stellar mass surface density gradients, we propose that the observed steepening is a consequence of local metal enrichment due to in-situ star formation during the inside-out formation of disk galaxies. The metallicity gradient-stellar mass relation is characterized by a rather large scatter, especially for $10^{9.8}<{\rm M_\star/M_\odot}<10^{10.5}$, and we demonstrate that metallicity gradients anti-correlate with the galaxy gas fraction. Focusing on the galaxy environment, at any given stellar mass, cluster galaxies have systematically flatter metallicity profiles than their field counterparts. Many sub-populations coexist in clusters: galaxies with shallower metallicity profiles appear to have fallen into their present host halo sooner and have experienced the environmental effects for a longer time than cluster galaxies with steeper metallicity profiles. Recent galaxy infallers, like galaxies currently undergoing ram-pressure stripping, show metallicity gradients more similar to those of field galaxies, suggesting they have not felt the effect of the cluster yet.
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GASP (GAs Stripping Phenomena in galaxies with MUSE) জরিপ থেকে 85টি ছায়াপথের MUSE পর্যবেক্ষণ এবং MaNGA (Mapping Nearby Galaxies at Apache Point Observatory জরিপ) থেকে একটি বৃহৎ নমুনার উপর ভিত্তি করে আমরা স্থানীয় গুচ্ছ ও ক্ষেত্রের ছায়াপথগুলির জন্য তারকীয় ভরের ফাংশন হিসাবে গ্যাস ধাতবতা ঢালের বন্টন নিয়ে গবেষণা করি। মোটের উপর, ধাতবতার প্রোফাইলগুলি $10^{10.3}\,{\rm M_\odot}$ পর্যন্ত তারকীয় ভর বৃদ্ধির সাথে সাথে খাড়া হয় এবং উচ্চতর ভরে সমতল হয়ে যায়। ধাতবতা প্রোফাইল এবং তারকীয় ভর পৃষ্ঠের ঘনত্ব ঢালের ফলাফলগুলি একত্রিত করে, আমরা প্রস্তাব করি যে পর্যবেক্ষিত খাড়া হওয়াটি চাকতি আকৃতির ছায়াপথগুলির অভ্যন্তরীণ থেকে বাহিরের দিকে গঠনের সময় স্থানীয় তারকার গঠনের ফলে স্থানীয় ধাতব সমৃদ্ধির ফলাফল। ধাতবতা ঢাল-তারকীয় ভর সম্পর্কটি বিশেষত $10^{9.8}<{\rm M_\star/M_\odot}<10^{10.5}$ এর জন্য বেশ বড় ছড়ানোর দ্বারা চিহ্নিত করা হয়, এবং আমরা দেখাই যে ধাতবতা ঢালগুলি ছায়াপথ গ্যাস ভগ্নাংশের সাথে বিপরীত সম্পর্ক দেখায়। ছায়াপথ পরিবেশের দিকে মনোনিবেশ করে, যেকোনো নির্দিষ্ট তারকীয় ভরের জন্য গুচ্ছ ছায়াপথগুলির ধাতবতার প্রোফাইল তাদের ক্ষেত্রের সদৃশ ছায়াপথগুলির তুলনায় সিস্টেম্যাটিকভাবে সমতল। গুচ্ছগুলিতে অনেক উপ-জনসংখ্যা একসাথে বাস করে: কম ঢালযুক্ত ধাতবতা প্রোফাইল সহ ছায়াপথগুলি মনে হয় তাদের বর্তমান হোস্ট হ্যালোতে আগে পড়েছে এবং খাড়া ধাতবতা প্রোফাইল সহ গুচ্ছ ছায়াপথগুলির তুলনায় দীর্ঘতর সময় ধরে পরিবেশগত প্রভাব অনুভব করেছে। সদ্য ছায়াপথ অনুপ্রবেশকারীরা, যেমন বর্তমানে র্যাম-চাপ স্ট্রিপিংয়ের মুখোমুখি ছায়াপথগুলি, ক্ষেত্র ছায়াপথগুলির সাথে আরও মিল রাখে এমন ধাতবতা ঢাল দেখায়, যা ইঙ্গিত দেয় যে তারা এখনও গুচ্ছের প্রভাব অনুভব করেনি।
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bn
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We present results from the zeroth-order imaging of a Chandra HETGS observation of the nearby Seyfert 2 galaxy Circinus. Twelve X-ray sources were detected in the ACIS-S image of the galaxy, embedded in diffuse X-ray emission. The latter shows a prominent (~18arcsec) soft ``plume'' in the N-W direction, coincident with the [OIII] ionization cone. The radial profiles of the brightest X-ray source at various energies are consistent with an unresolved (FWHM ~0.8arcsec) component, which we identify as the active nucleus, plus two extended components with FWHMs ~ 2.3arcsec and 18arcsec, respectively. In a radius of 3arcsec, the nucleus contributes roughly the same flux as the extended components at the softest energies (< 2 keV). However, at harder energies (> 2 keV), the contribution of the nucleus is dominant. The zeroth-order ACIS spectrum of the nucleus exhibits emission lines at both soft and hard X-rays, including a prominent Fe Kalpha line at 6.4 keV, showing that most of the X-ray lines previously detected with ASCA originate in a compact region (<15 pc). Based on its X-ray spectrum, we argue that the 2.3arcsec extended component is scattered nuclear radiation from nearby ionized gas. The large-scale extended component includes the emission from the N-W plume and possibly from the outer starburst ring.
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Біз жақын орналасқан Сейферт 2 галактикасы — Циркуль бойынша Chandra HETGS бақылауының нөлдік ретті бейнелеу нәтижелерін ұсынамыз. Галактиканың ACIS-S бейнесінде диффузиялық рентген сәулесінің ортасында он екі рентген көзі табылды. Соңғысы солтүстік-батыс бағытта [OIII] иондау конусымен сәйкес келетін бір айқын (≈18arcsec) жұмсақ «желбіршекті» көрсетеді. Әртүрлі энергиялардағы ең жарық рентген көзінің радиалдық профилдері шешілмеген (FWHM ≈0,8arcsec) компонентпен, сондай-ақ FWHM-і шамамен 2,3arcsec және 18arcsec болатын екі кеңейтілген компонентпен сәйкес келеді, олардың бірін біз белсенді ядро ретінде анықтаймыз. 3arcsec радиусында ядро жұмсақтығы ең төмен энергияларда (< 2 кэВ) кеңейтілген компоненттермен шамамен бірдей ағын үлесін қосады. Алайда, қаттырақ энергияларда (> 2 кэВ) ядроның үлесі басым болады. Ядроның нөлдік ретті ACIS спектрі жұмсақ және қатты рентген сәулелерінде, соның ішінде 6,4 кэВ-тағы айқын Fe Kalpha сызығында шығару сызықтарын көрсетеді, бұл ASCA-мен бұрын анықталған рентген сызықтарының көбі компактты аймақта (<15 пк) пайда болғанын көрсетеді. Оның рентген спектрі негізінде біз 2,3arcsec кеңейтілген компоненті жақын иондалған газдан шашыраған ядролық сәулелену екенін болжаймыз. Үлкен масштабты кеңейтілген компонент солтүстік-батыс желбіршегінің шығаруын және, мүмкін, сыртқы жұлдызды жарқыл сақинасын қамтиды.
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kk
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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.
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Ledakan Radio Pantas (FRB) adalah denyutan radio terang yang penuh teka-teki dengan tempoh kira-kira milisaat yang berasal dari jarak luar galaksi. Sebagai sebahagian daripada projek MeerTRAP, kami menggunakan tatasusunan teleskop MeerKAT di Afrika Selatan untuk mencari dan menentukan lokasi denyutan tersebut secara tepat dalam masa sebenar. Matlamat kami adalah untuk menentukan lokasi tepat FRB ke galaksi perumahnya dan dengan itu memahami bagaimana ia terbentuk. Namun begitu, sifat sementara FRB membawa pelbagai cabaran, seperti dalam reka bentuk sistem, kuasa pengiraan kasar dan komunikasi masa sebenar, di mana keperluan masa sebenar adalah agak ketat (beberapa puluh saat). Pemprosesan data yang pantas adalah penting bagi kami untuk dapat mengekalkan data resolusi tinggi denyutan tersebut, menentukan lokasinya, dan meminimumkan kelewatan bagi pemerhatian susulan. Kami memberikan gambaran ringkas tentang paip talian analisis data, menghuraikan cabaran-cabaran yang dihadapi, serta menerangkan secara terperinci rekabentuk awal dan pelaksanaan infrastruktur pencetus masa sebenar untuk FRB di teleskop MeerKAT.
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ms
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Using the density-matrix renormalization group technique, we study a one-dimensional spin-$\frac{1}{2}$ Heisenberg chain consisting of coupled tetramers as an effective spin model for copper vanadate CuInVO$_5$. We obtain the ground-state phase diagram as a function of intra-tetramer and inter-tetramer exchange interactions, exhibiting two multimerized valence-bond-solid (VBS) phases : one is characterized by the formation of tetramer-singlet units; the other by the formation of dimer-singlet pairs. We show that the finite spin gaps in both the VBS phases smoothly vanish at the phase boundary: a second order phase transition defining a quantum critical point (QCP). The phase boundary is also captured by the fact that the central charge is unity at the phase boundary and zero otherwise in the thermodynamic limit. We further demonstrate that the experimental magnetization curve (which starts increasing with zero or tiny field) can be reasonably explained only by assuming the exchange parameters of CuInVO$_5$ to be very close to the phase boundary. Thus, we argue that CuInVO$_5$ may be a first example material which at ambient pressure stands near a QCP between two VBS phases. By varying the balance of exchange interactions with pressure, a transition from N\'eel to either of the VBS phases could be observed.
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ঘনত্ব-ম্যাট্রিক্স পুনঃসামান্যকরণ গ্রুপ কৌশল ব্যবহার করে, আমরা কপার ভ্যানাডেট CuInVO$_5$-এর জন্য একটি কার্যকর স্পিন মডেল হিসাবে যুক্ত টেট্রামারগুলির গঠনকারী এক-মাত্রিক স্পিন-$\frac{1}{2}$ হেইজেনবার্গ শৃঙ্খলের অধ্যয়ন করি। আমরা টেট্রামার-অভ্যন্তরীণ এবং টেট্রামার-মধ্যবর্তী বিনিময় মিথস্ক্রিয়ার ফাংশন হিসাবে ভূমি-অবস্থার পর্যায় চিত্র পাই, যা দুটি বহুলকীকৃত ভ্যালেন্স-বন্ড-সলিড (VBS) পর্যায় প্রদর্শন করে: একটি টেট্রামার-সিঙ্গলেট এককের গঠনের দ্বারা চিহ্নিত হয়; অন্যটি ডাইমার-সিঙ্গলেট জোড়ের গঠনের দ্বারা। আমরা দেখাই যে উভয় VBS পর্যায়ে সসীম স্পিন ফাঁকগুলি পর্যায় সীমানায় মসৃণভাবে শূন্যে পরিণত হয়: একটি দ্বিতীয় ক্রমের পর্যায় রূপান্তর যা একটি কোয়ান্টাম সমালোচনা বিন্দু (QCP) নির্ধারণ করে। তাপগতীয় সীমায় পর্যায় সীমানায় কেন্দ্রীয় চার্জের একক এবং অন্যত্র শূন্য হওয়ার তথ্যটি দ্বারাও পর্যায় সীমানাটি ধরা পড়ে। আমরা আরও দেখাই যে পরীক্ষালব্ধ চৌম্বকীকরণ বক্ররেখা (যা শূন্য বা অতি ক্ষুদ্র ক্ষেত্রের সাথে বৃদ্ধি পায়) কেবলমাত্র CuInVO$_5$-এর বিনিময় পরামিতির পর্যায় সীমানার খুব কাছাকাছি থাকার ধারণা করলেই যুক্তিযুক্তভাবে ব্যাখ্যা করা যায়। সুতরাং, আমরা যুক্তি দেই যে CuInVO$_5$ প্রথম উদাহরণের উপাদান হতে পারে যা স্বাভাবিক চাপে দুটি VBS পর্যায়ের মধ্যে একটি QCP-এর কাছাকাছি অবস্থান করে। চাপের সাথে বিনিময় মিথস্ক্রিয়ার ভারসাম্য পরিবর্তন করে N\'eel থেকে যে কোনো একটি VBS পর্যায়ে রূপান্তর পর্যবেক্ষণ করা যেতে পারে।
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bn
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