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Majorana neutrinos in the seesaw model can have sizable mixings through which they can be produced at the Large Hadron Collider (LHC) and show a remarkable Lepton Number Violating (LNV) signature. In this article we study the LNV decay of the W boson via two almost degenerate heavy on-shell Majorana neutrinos $N_j$, into three charged leptons and a light neutrino. We consider the scenario where the heavy neutrino masses are within $1$ GeV $\leq M_N \leq 10$ GeV. We evaluated the possibility to measure a LNV oscillation process in such a scenario, namely, the modulation of the quantity $d \Gamma/d L$ for the process at the LHC where $W^{\pm} \to \mu^{\pm} N \to \mu^{\pm} \tau^{\pm} W^{\mp *}$ $ \to \mu^{\pm} \tau^{\pm} e^{\mp} \nu_e$. $L$ is the distance within the detector between the two vertices of the process. We found out some realistic conditions under which such a modulation could be probed at the LHC.
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ในแบบจำลองซีซอว์ นิวตริโนแบบมาโจราณาอาจมีการผสมผสานกันในระดับที่สังเกตได้ ซึ่งทำให้สามารถผลิตอนุภาคเหล่านี้ที่เครื่องชนอนุภาคขนาดใหญ่ (LHC) และแสดงลายเซ็นที่โดดเด่นของการฝ่าฝืนกฎจำนวนเลปตอน (LNV) ได้ ในบทความนี้ เราศึกษาการสลายตัวแบบ LNV ของโบซอน W ผ่านนิวตริโนมาโจราณาหนักสองตัวที่เกือบมีมวลซ้อนทับกัน $N_j$ ไปเป็นเลปตอนมีประจุสามตัวและนิวตริโนเบา เราพิจารณาสถานการณ์ที่มวลของนิวตริโนหนักอยู่ในช่วง $1$ จิกะอิเล็กตรอนโวลต์ $\leq M_N \leq 10$ จิกะอิเล็กตรอนโวลต์ เราประเมินความเป็นไปได้ในการวัดกระบวนการสั่นของ LNV ในสถานการณ์ดังกล่าว โดยเฉพาะการเปลี่ยนแปลงของขนาด $d \Gamma/d L$ สำหรับกระบวนการที่ LHC ซึ่ง $W^{\pm} \to \mu^{\pm} N \to \mu^{\pm} \tau^{\pm} W^{\mp *}$ $ \to \mu^{\pm} \tau^{\pm} e^{\mp} \nu_e$ โดย $L$ คือระยะทางภายในเครื่องตรวจจับระหว่างจุดกำเนิดสองจุดของกระบวนการ เราพบเงื่อนไขบางประการที่เป็นจริงได้ ซึ่งสามารถใช้ตรวจสอบการเปลี่ยนแปลงดังกล่าวที่ LHC ได้
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th
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We present high-resolution, high-sensitivity radio images of the ultra-luminous infrared galaxy (ULIRG) IRAS 23365+3604. We performed contemporaneous observations at 1.7 and 5.0 GHz, in three epochs separated by one year from each other, with the European very long baseline interferometry Network (EVN). We also present complementary Multi-Element Radio Linked Interferometry Network (MERLIN) at 1.6 and 5.0 GHz, and archival Very Large Array (VLA) data, taken at 1.4 and 4.9 GHz. We find that the emission at ~5.0 GHz remains quite compact as seen at different resolutions, whereas at ~1.7 GHz, high resolution imaging reveals some extended structure. The nuclear region has an approximate linear size of 200 pc and shows the presence of two main emission components: i) one with a composite spectrum due to ongoing non-thermal activity (probably due to recently exploded supernovae and AGN activity), ii) another one with a steep spectrum, likely dominated by an old population of radio emitters, such as supernova remnants (SNRs). Radiative losses are important, so re-acceleration or replenishment of new electrons is necessary. We estimate a magnetic field strength of 18 \mu G at galactic, and 175 \mu G at nuclear scales, which are typical for galaxies in advanced mergers.
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Představujeme radiové snímky ultra-jasné infračervené galaxie (ULIRG) IRAS 23365+3604 s vysokým rozlišením a citlivostí. Provedli jsme současné pozorování na frekvencích 1,7 a 5,0 GHz ve třech epizodách, vzájemně vzdálených o jeden rok, pomocí Evropské sítě velmi dlouhých základen (EVN). Dále prezentujeme doplňující data z Multi-Element Radio Linked Interferometry Network (MERLIN) na frekvencích 1,6 a 5,0 GHz a archivní data z Very Large Array (VLA) pořízená na frekvencích 1,4 a 4,9 GHz. Zjistili jsme, že záření na frekvenci přibližně 5,0 GHz zůstává poměrně kompaktní při různých rozlišeních, zatímco na frekvenci přibližně 1,7 GHz odhaluje zobrazování s vysokým rozlišením určitou rozšířenou strukturu. Jádrová oblast má přibližnou lineární velikost 200 pc a vykazuje přítomnost dvou hlavních složek záření: i) jedné se složeným spektrem způsobeným probíhající netepelnou aktivitou (pravděpodobně v důsledku nedávných explozí supernov a AGN aktivitou), ii) druhé se strmým spektrem, která je pravděpodobně ovlivněna starší populací radiových zdrojů, jako jsou pozůstatky po supernovách (SNR). Radiativní ztráty jsou významné, proto je nutné znovunabíjení nebo doplňování nových elektronů. Odhadujeme intenzitu magnetického pole na 18 μG na galaktické úrovni a 175 μG na úrovni jádra, což je typické pro galaxie v pokročilé fázi srážky.
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cs
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In this paper, we analyze a composite decode-and-forward scheme for the two-way relay channel with a direct link. During transmission, our scheme combines both block Markov coding and an independent coding scheme similar to network coding at the relay. The main contribution of this work is to examine how link state impacts the allocation of power between these two distinct techniques, which in turn governs the necessity of each technique in achieving the largest transmission rate region. We analytically determine the link-state regimes and associated relaying techniques. Our results illustrate an interesting trend: when the user-to-relay link is marginally stronger than the direct link, it is optimal to use only independent coding. In this case, the relay need not use full power. However, for larger user-to-relay link gains, the relay must supplement independent coding with block Markov coding to achieve the largest rate region. These link-state regimes are important for the application of two-way relaying in 5G networks, such as in D2D mode or relay-aided transmission.
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In questo articolo, analizziamo uno schema composito di tipo decode-and-forward per il canale di relè bidirezionale con collegamento diretto. Durante la trasmissione, il nostro schema combina sia la codifica block Markov sia uno schema di codifica indipendente simile alla network coding presso il relè. Il contributo principale di questo lavoro consiste nello studio di come lo stato del collegamento influisca sull'allocazione della potenza tra queste due tecniche distinte, il che a sua volta determina la necessità di ciascuna tecnica per raggiungere la massima regione di velocità trasmissiva. Determiniamo analiticamente i regimi di stato del collegamento e le tecniche di relè associate. I nostri risultati evidenziano una tendenza interessante: quando il collegamento da utente a relè è marginalmente più forte del collegamento diretto, è ottimale utilizzare soltanto la codifica indipendente. In questo caso, il relè non deve utilizzare tutta la potenza disponibile. Tuttavia, per guadagni maggiori del collegamento da utente a relè, il relè deve affiancare alla codifica indipendente anche la codifica block Markov per raggiungere la massima regione di velocità. Questi regimi di stato del collegamento sono importanti per l'applicazione del relè bidirezionale nelle reti 5G, come ad esempio nella modalità D2D o nella trasmissione assistita da relè.
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it
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Binary black holes on quasicircular orbits with spins aligned with their orbital angular momentum have been testbeds for analytic and numerical relativity for decades, not least because symmetry ensures that such configurations are equilibrium solutions to the spin-precession equations. In this work, we show that these solutions can be unstable when the spin of the higher-mass black hole is aligned with the orbital angular momentum and the spin of the lower-mass black hole is anti-aligned. Spins in these configurations are unstable to precession to large misalignment when the binary separation $r$ is between the values $r_{\rm ud\pm}= (\sqrt{\chi_1} \pm \sqrt{q \chi_2})^4 (1-q)^{-2} M$, where $M$ is the total mass, $q \equiv m_2/m_1$ is the mass ratio, and $\chi_1$ ($\chi_2$) is the dimensionless spin of the more (less) massive black hole. This instability exists for a wide range of spin magnitudes and mass ratios and can occur in the strong-field regime near merger. We describe the origin and nature of the instability using recently developed analytical techniques to characterize fully generic spin precession. This instability provides a channel to circumvent astrophysical spin alignment at large binary separations, allowing significant spin precession prior to merger affecting both gravitational-wave and electromagnetic signatures of stellar-mass and supermassive binary black holes.
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Lubang hitam dedua perduaan pada orbit hampir membulat dengan putaran selari dengan momentum sudut orbit mereka telah menjadi landasan ujian kepada kerelativan analitik dan berangka selama beberapa dekad, tidak kurang kerana simetri memastikan bahawa konfigurasi sedemikian merupakan penyelesaian keseimbangan kepada persamaan praesusi putaran. Dalam karya ini, kami menunjukkan bahawa penyelesaian ini boleh menjadi tidak stabil apabila putaran lubang hitam yang lebih berjisim adalah selari dengan momentum sudut orbit dan putaran lubang hitam yang kurang berjisim adalah bertentangan arah. Putaran dalam konfigurasi ini tidak stabil terhadap praesusi kepada ketidakselarasan besar apabila pemisahan dedua $r$ berada di antara nilai-nilai $r_{\rm ud\pm}= (\sqrt{\chi_1} \pm \sqrt{q \chi_2})^4 (1-q)^{-2} M$, dengan $M$ ialah jisim keseluruhan, $q \equiv m_2/m_1$ ialah nisbah jisim, dan $\chi_1$ ($\chi_2$) ialah putaran tanpa dimensi bagi lubang hitam yang lebih (kurang) berjisim. Ketidakstabilan ini wujud bagi julat yang luas magnitud putaran dan nisbah jisim dan boleh berlaku dalam kawasan medan kuat berhampiran peleburan. Kami menerangkan asal usul dan sifat ketidakstabilan ini menggunakan teknik analitik yang baru dibangunkan untuk mewatakkan sepenuhnya praesusi putaran generik. Ketidakstabilan ini menyediakan satu saluran untuk mengelakkan penyelarasan putaran astrophizikal pada pemisahan dedua yang besar, membolehkan praesusi putaran yang ketara sebelum peleburan yang memberi kesan kepada isyarat gelombang graviti dan elektromagnet bagi dedua lubang hitam berjisim bintang dan supermasif.
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ms
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Gerhard had recently analyzed the data on seven dwarf spheroidals, and concluded that these disagree with the predictions of MOND. We contend that this conclusion is anything but correct. With new data for three of the dwarfs the observations of all dwarfs are in compelling agreement with the predictions of MOND. Gerhard found MOND M/L values that fall around a few solar units, as expected if MOND is a valid alternative to dark matter. His sole cause for complaint was that some of his MOND M/L values were still outside the range of ``reasonable'' stellar values. This, we say, was easily attributable to uncertainties in the data, such as in the velocity dispersions, luminosities, core radii, etc., and in the assumptions that underlie the analysis, such as isotropic velocity distribution, light-distribution fits, etc.. There are now new, much improved determinations of the velocity dispersions for three of the dwarfs, in particular for the two dwarfs for which Gerhard found high MOND M/L values. In fact, within just the quoted errors on the velocity dispersions and the luminosities, the MOND M/L values for all seven dwarfs are now perfectly consistent with stellar values, with no need for dark matter.
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เกอร์ฮาร์ดได้วิเคราะห์ข้อมูลจากกาแล็กซีแคระรูปทรงกลมเจ็ดแห่งเมื่อไม่นานมานี้ และสรุปว่าข้อมูลเหล่านี้ขัดแย้งกับการทำนายของทฤษฎี MOND เราขอโต้แย้งว่าข้อสรุปดังกล่าวไม่ถูกต้องอย่างยิ่ง ด้วยข้อมูลใหม่สำหรับกาแล็กซีแคระสามแห่ง ข้อมูลสังเกตการณ์ของกาแล็กซีแคระทั้งหมดกลับสอดคล้องกับการทำนายของ MOND อย่างน่าประทับใจ เกอร์ฮาร์ดได้ค่ามวลต่อความสว่าง (M/L) ภายใต้ MOND ที่อยู่ในระดับไม่กี่หน่วยของค่าสุริยะ ซึ่งเป็นไปตามที่คาดไว้หาก MOND เป็นทางเลือกที่ถูกต้องแทนสสารมืด สิ่งเดียวที่เขาติดใจคือค่า M/L ภายใต้ MOND บางค่ายังอยู่นอกช่วงของค่ามวลต่อความสว่างจากดาวฤกษ์ที่ถือว่า "สมเหตุสมผล" ซึ่งเราขอชี้แจงว่าสาเหตุนี้สามารถอธิบายได้ง่ายว่าเกิดจากความไม่แน่นอนของข้อมูล เช่น ความคลาดเคลื่อนของการกระจายความเร็ว ความสว่าง รัศมีแกนกลาง ฯลฯ และข้อสมมติที่ใช้ในการวิเคราะห์ เช่น การกระจายความเร็วแบบไอโซทรอปิก การประมาณรูปแบบการกระจายของแสง ฯลฯ ขณะนี้มีข้อมูลใหม่ที่แม่นยำกว่ามากสำหรับค่าการกระจายความเร็วของกาแล็กซีแคระสามแห่ง โดยเฉพาะสองแห่งที่เกอร์ฮาร์ดพบค่า M/L ภายใต้ MOND สูงมาก ที่จริงแล้ว แม้เพียงพิจารณาความคลาดเคลื่อนที่รายงานไว้ของค่าการกระจายความเร็วและความสว่าง ค่า M/L ภายใต้ MOND สำหรับกาแล็กซีแคระทั้งเจ็ดแห่งก็สอดคล้องอย่างสมบูรณ์กับค่าที่คาดไว้จากดาวฤกษ์ โดยไม่จำเป็นต้องอ้างถึงสสารมืดอีกต่อไป
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th
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Nonadiabatic geometric phases are only dependent on the evolution path of a quantum system but independent of the evolution details, and therefore quantum computation based on nonadiabatic geometric phases is robust against control errors. To realize nonadiabatic geometric quantum computation, it is necessary to ensure that the quantum system undergoes a cyclic evolution and the dynamical phases are removed from the total phases. To satisfy these conditions, the evolution paths in previous schemes are usually restricted to some special forms, e.g, orange-slice-shaped loops, which make the paths unnecessarily long in general. In this paper, we put forward an approach to the realization of nonadiabatic geometric quantum computation by which a universal set of nonadiabatic geometric gates can be realized with any desired evolution paths. Our approach makes it possible to realize geometric quantum computation with an economical evolution time so the influence of environment noises on the quantum gates can be minimized further.
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Các pha hình học không đoạn nhiệt chỉ phụ thuộc vào quỹ đạo tiến hóa của một hệ lượng tử mà không phụ thuộc vào các chi tiết tiến hóa, do đó phép tính lượng tử dựa trên các pha hình học không đoạn nhiệt có độ bền cao trước các lỗi điều khiển. Để thực hiện phép tính lượng tử hình học không đoạn nhiệt, cần đảm bảo rằng hệ lượng tử trải qua một quá trình tiến hóa tuần hoàn và các pha động lực học bị loại bỏ khỏi các pha toàn phần. Để thỏa mãn các điều kiện này, các quỹ đạo tiến hóa trong các phương án trước đây thường bị giới hạn ở một số dạng đặc biệt, ví dụ như các vòng tròn hình múi cam, điều này thường khiến các quỹ đạo trở nên dài hơn mức cần thiết. Trong bài báo này, chúng tôi đề xuất một phương pháp thực hiện phép tính lượng tử hình học không đoạn nhiệt, cho phép thực hiện một tập đầy đủ các cổng hình học không đoạn nhiệt với bất kỳ quỹ đạo tiến hóa mong muốn nào. Phương pháp của chúng tôi làm cho việc thực hiện phép tính lượng tử hình học với thời gian tiến hóa tiết kiệm hơn trở nên khả thi, nhờ đó ảnh hưởng của nhiễu môi trường lên các cổng lượng tử có thể được giảm thiểu thêm.
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vi
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We report the thermoelectric (TE) properties of (1-x)LaCoO3.xLa0.7Sr0.3MnO3 (0 < x < 0.10) composite in a temperature range 320-800 K. Addition of La0.7Sr0.3MnO3 to LaCoO3 in small amount (5 weight %) improves the overall Seebeck coefficient ({\alpha}) at higher temperatures. The electrical conductivity, however, decreases due to a decrease in carrier concentration of the composite. The decrease in electrical conductivity of the composite at high temperature may be attributed to the insulating nature of the LSMO above room temperature. Thermal conductivity (\k{appa}) of all the samples increases with an increase in the temperature but decreases with increasing LSMO content. We also report the local variation of the Seebeck coefficient across the composite samples measured using a precision Seebeck measurement system. A maximum value of 0.09 for the figure of merit (ZT) is obtained for 0.95LaCoO3.0.05La0.7Sr0.3MnO3 at 620 K which is significantly higher than the ZT of either of LaCoO3 or La0.7Sr0.3MnO3 at 620 K. This suggests the potential for enhancement of operating temperatures of hitherto well known low-temperature thermoelectric materials through suitable compositing approach.
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ہم (1-x)LaCoO3.xLa0.7Sr0.3MnO3 (0 < x < 0.10) مرکب کی حرارت برقی (TE) خصوصیات کی رپورٹ 320-800 K درجہ حرارت کی حد میں پیش کرتے ہیں۔ لاکوO3 میں چھوٹی مقدار (5 فیصد وزنی) La0.7Sr0.3MnO3 کے اضافے سے زیادہ درجہ حرارت پر مجموعی سیبیک کوائفیشنٹ ({\alpha}) میں بہتری آتی ہے۔ تاہم، برقی موصلیت کم ہوجاتی ہے کیونکہ مرکب کی حاملہ تعداد کم ہوجاتی ہے۔ اونچے درجہ حرارت پر مرکب کی برقی موصلیت میں کمی کی وجہ کمرے کے درجہ حرارت سے اوپر LSMO کی عُزلت خصوصیت ہوسکتی ہے۔ تمام نمونوں کی حرارتی موصلیت (\k{appa}) درجہ حرارت میں اضافے کے ساتھ بڑھتی ہے لیکن LSMO کی مقدار میں اضافے کے ساتھ کم ہوتی ہے۔ ہم مرکب نمونوں کے سراسر سیبیک کوائفیشنٹ کی مقامی تغیرات کی رپورٹ بھی پیش کرتے ہیں جو ایک درست سیبیک پیمائش سسٹم کے ذریعہ ماپی گئی تھی۔ 0.95LaCoO3.0.05La0.7Sr0.3MnO3 کے لیے 620 K پر معیاری عدد (ZT) کی زیادہ سے زیادہ قیمت 0.09 حاصل ہوئی، جو 620 K پر لاکوO3 یا La0.7Sr0.3MnO3 دونوں کے ZT سے کافی زیادہ ہے۔ اس سے پتہ چلتا ہے کہ مناسب مرکب بنانے کے طریقہ کار کے ذریعہ اب تک جانے جانے والے کم درجہ حرارت والے حرارت برقی مواد کے کام کرنے کے درجہ حرارت میں بہتری کی صلاحیت موجود ہے۔
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ur
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Efficient exploration remains a challenging problem in reinforcement learning, especially for those tasks where rewards from environments are sparse. A commonly used approach for exploring such environments is to introduce some "intrinsic" reward. In this work, we focus on model uncertainty estimation as an intrinsic reward for efficient exploration. In particular, we introduce an implicit generative modeling approach to estimate a Bayesian uncertainty of the agent's belief of the environment dynamics. Each random draw from our generative model is a neural network that instantiates the dynamic function, hence multiple draws would approximate the posterior, and the variance in the future prediction based on this posterior is used as an intrinsic reward for exploration. We design a training algorithm for our generative model based on the amortized Stein Variational Gradient Descent. In experiments, we compare our implementation with state-of-the-art intrinsic reward-based exploration approaches, including two recent approaches based on an ensemble of dynamic models. In challenging exploration tasks, our implicit generative model consistently outperforms competing approaches regarding data efficiency in exploration.
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Etkin keşif, özellikle çevreden gelen ödüllerin seyrek olduğu görevlerde, pekiştirmeli öğrenmede zorlu bir problem olmaya devam etmektedir. Böyle ortamları keşfetmek için yaygın olarak kullanılan bir yaklaşım bazı "içsel" ödüller eklemektir. Bu çalışmada, etkin keşif için içsel ödül olarak model belirsizliği tahmini üzerinde odaklanıyoruz. Özellikle, ajanın çevre dinamiklerine dair inancının Bayesçi belirsizliğini tahmin etmek amacıyla örtük bir üretici modelleme yaklaşımı sunuyoruz. Üretici modelimizden yapılan her rastgele çekiliş, dinamik fonksiyonu somutlaştıran bir sinir ağıdır; bu nedenle birden fazla çekiliş, posterior dağılımı yaklaşık olarak verir ve bu posterior dağılıma dayalı gelecekteki tahminlerdeki varyans, keşif için içsel bir ödül olarak kullanılır. Üretici modelimiz için amortismanlı Stein Varyasyonel Gradyan İnişine dayalı bir eğitim algoritması tasarladık. Deneylerde, son zamanlarda dinamik modellerin birleşimine dayalı iki yaklaşımı da içeren, içsel ödüle dayalı en ileri düzey keşif yöntemleriyle uygulamamızı karşılaştırıyoruz. Zorlu keşif görevlerinde, örtük üretici modelimiz keşifte veri verimliliği açısından rakip yaklaşımları tutarlı bir şekilde geride bırakmaktadır.
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tr
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It was shown recently that the anomalous scaling of simultaneous correlation functions in turbulence is intimately related to the breaking of temporal scale invariance, which is equivalent to the appearance of infinitely many times scales in the time dependence of time-correlation functions. In this paper we derive a continued fraction representation of turbulent time correlation functions which is exact and in which the multiplicity of time scales is explicit. We demonstrate that this form yields precisely the same scaling laws for time derivatives and time integrals as the "multi-fractal" representation that was used before. Truncating the continued fraction representation yields the "best" estimates of time correlation functions if the given information is limited to the scaling exponents of the simultaneous correlation functions up to a certain, finite order. It is worth noting that the derivation of a continued fraction representation obtained here for an operator which is not Hermitian or anti-Hermitian may be of independent interest.
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Gần đây đã chỉ ra rằng sự thay đổi thang đo bất thường của các hàm tương quan đồng thời trong dòng chảy hỗn loạn có liên quan mật thiết đến sự phá vỡ tính bất biến thang đo thời gian, điều này tương đương với sự xuất hiện của vô số thang thời gian trong sự phụ thuộc thời gian của các hàm tương quan theo thời gian. Trong bài báo này, chúng tôi suy ra một biểu diễn phân số liên tục của các hàm tương quan theo thời gian trong dòng chảy hỗn loạn, biểu diễn này là chính xác và trong đó sự đa dạng của các thang thời gian được thể hiện rõ ràng. Chúng tôi chứng minh rằng dạng này cho ra các quy luật thay đổi thang đo đối với đạo hàm theo thời gian và tích phân theo thời gian hoàn toàn giống như biểu diễn "đa phân số" đã được sử dụng trước đây. Việc cắt ngắn biểu diễn phân số liên tục sẽ cho ra các ước lượng "tốt nhất" của các hàm tương quan theo thời gian nếu thông tin đã biết bị giới hạn ở các số mũ thay đổi thang đo của các hàm tương quan đồng thời đến một bậc hữu hạn nhất định. Cần lưu ý rằng việc suy ra biểu diễn phân số liên tục ở đây đối với một toán tử không phải là Hermit hay phản Hermit có thể mang ý nghĩa độc lập.
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Ultra-high-energy cosmic rays (UHECRs) are the highest energy messengers in the universe, with energies up to $10^{20}$ eV. Studies of astrophysical particles (nuclei, electrons, neutrinos and photons) at their highest observed energies have implications for fundamental physics as well as astrophysics. The primary particles interact in the atmosphere (or in the Earth) and generate extensive air showers. Analysis of those showers enables one not only to estimate the energy, direction and most probable mass of the primary cosmic particles, but also to obtain information about the properties of their hadronic interactions at energies more than one order of magnitude above that accessible with the current highest energy human-made accelerator. The Pierre Auger Observatory, located in the province of Mendoza, Argentina, is the largest cosmic ray experiment ever built. The observatory was designed as a hybrid detector covering an area of 3000 km$^2$ and has been taking data for almost twenty years. In this paper, a selection of the latest results is presented: the cosmic ray energy spectrum, studies of hadronic physics, searches for a directional anisotropy and studies of mass composition (including the photon and neutrino searches). Finally, the current upgrade ("AugerPrime") of the observatory, which is mostly aimed at improving the sensitivity to the particle type and mass of ultra-high energy cosmic rays, is described.
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초고에너지 우주선(UHECRs)은 최대 $10^{20}$ eV의 에너지를 가진, 우주에서 가장 높은 에너지를 지닌 정보 전달자이다. 관측된 가장 높은 에너지를 가진 천체물리학적 입자(원자핵, 전자, 중성미자 및 광자)에 대한 연구는 천체물리학뿐 아니라 기본 물리학에도 중요한 시사점을 제공한다. 초기 입자들은 대기 중(또는 지구 내)에서 상호작용하며 광범위한 대기 캐스케이드(에어 샤워)를 생성한다. 이러한 캐스케이드의 분석을 통해 초기 우주선 입자의 에너지, 방향, 가장 가능성 높은 질량을 추정할 수 있을 뿐 아니라, 현재 인간이 만든 가장 높은 에너지 가속기에서 달성 가능한 에너지보다 한 차수 이상 높은 에너지 영역에서의 강입자 상호작용 특성에 관한 정보도 얻을 수 있다. 아르헨티나 멘도사 주에 위치한 피에르 오귀르 관측소는 지금까지 건설된 가장 큰 우주선 실험 시설이다. 이 관측소는 3000 km$^2$의 면적을 커버하는 하이브리드 탐지기로 설계되었으며, 거의 20년 동안 데이터를 수집해 왔다. 본 논문에서는 최신 결과들 중 일부를 소개한다. 즉, 우주선 에너지 스펙트럼, 강입자 물리학 연구, 방향성 비등방성 탐색, 질량 조성 연구(광자 및 중성미자 탐색 포함) 등을 다룬다. 마지막으로, 초고에너지 우주선의 입자 종류 및 질량에 대한 감도 향상에 주로 목표를 둔 관측소의 현재 업그레이드 사업("AugerPrime")에 대해서도 설명한다.
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Massive rotating single stars with an initial metal composition appropriate for the dwarf galaxy I Zw 18 ([Fe/H]=$-$1.7) are modelled during hydrogen burning for initial masses of 9-300 M$_{\odot}$ and rotational velocities of 0-900 km s$^{-1}$. Internal mixing processes in these models were calibrated based on an observed sample of OB-type stars in the Magellanic Clouds. Even moderately fast rotators, which may be abundant at this metallicity, are found to undergo efficient mixing induced by rotation resulting in quasi chemically-homogeneous evolution. These homogeneously-evolving models reach effective temperatures of up to 90 kK during core hydrogen burning. This, together with their moderate mass-loss rates, make them Transparent Wind Ultraviolet INtense stars (TWUIN star), and their expected numbers might explain the observed HeII ionizing photon flux in I Zw 18 and other low-metallicity HeII galaxies. Our slowly rotating stars above $\sim$80 M$_{\odot}$ evolve into late B- to M-type supergiants during core hydrogen burning, with visual magnitudes up to 19$^{\mathrm{m}}$ at the distance of I Zw 18. Both types of stars, TWUIN stars and luminous late-type supergiants, are only predicted at low metallicity. Massive star evolution at low metallicity is shown to differ qualitatively from that in metal-rich environments. Our grid can be used to interpret observations of local star-forming dwarf galaxies and high-redshift galaxies, as well as the metal-poor components of our Milky Way and its globular clusters.
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I Zw 18 cüce galaksisi için uygun olan başlangıç metalik bileşime ([Fe/H]=$-$1.7) sahip, 9-300 M$_{\odot}$ başlangıç kütleleri ve 0-900 km s$^{-1}$ dönme hızları için hidrojen yanması sürecindeki büyük dönen tek yıldızlar modellenmiştir. Bu modellerdeki iç karışım süreçleri, Büyük ve Küçük Macellan Bulutları'ndaki gözlemlenen OB-tipi yıldız örnekleri temel alınarak kalibre edilmiştir. Bu metalik düzeyde bol miktarda bulunabilecek orta derecede hızlı dönen yıldızların, dönmenin etkisiyle verimli karışım gösterdiği ve neredeyse kimyasal olarak homojen evrim geçirdiği bulunmuştur. Bu homojen evrilen modeller, çekirdek hidrojen yanması sırasında etkin sıcaklıklarını 90 kK'ye kadar çıkarabilmektedir. Bu durum, bunların aynı zamanda orta düzeydeki kütle kaybı oranlarıyla birlikte, Şeffaf Rüzgar Ultraviyole Yoğun yıldızlar (TWUIN yıldızı) olmalarına neden olur ve beklenen sayıları, I Zw 18 ve diğer düşük metalik HeII galaksilerinde gözlenen HeII iyonlaştırıcı foton akısını açıklayabilir. I Zw 18'in uzaklığında, $\sim$80 M$_{\odot}$ üzerindeki yavaş dönen yıldızlarımız çekirdek hidrojen yanması sırasında geç B- ve M-tipi süperdevler haline gelir ve görünür büyüklükleri 19$^{\mathrm{m}}$'ye kadar çıkar. Hem TWUIN yıldızları hem de parlak geç tip süperdevler yalnızca düşük metalik düzeylerde öngörülmektedir. Düşük metalikteki büyük yıldız evriminin, yüksek metalikli ortamlardakinden niteliksel olarak farklı olduğu gösterilmiştir. Bu model ağı, yerel yıldız oluşumlu cüce galaksilerin, yüksek kırmızıya kayma gösteren galaksilerin yanı sıra Samanyolu'muzun ve globüler kümelerinin metal-fakir bileşenlerinin gözlemlerini yorumlamak için kullanılabilir.
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While large-scale language models (LMs) are able to imitate the distribution of natural language well enough to generate realistic text, it is difficult to control which regions of the distribution they generate. This is especially problematic because datasets used for training large LMs usually contain significant toxicity, hate, bias, and negativity. We propose GeDi as an efficient method for using smaller LMs as generative discriminators to guide generation from large LMs to make them safer and more controllable. GeDi guides generation at each step by computing classification probabilities for all possible next tokens via Bayes rule by normalizing over two class-conditional distributions; one conditioned on the desired attribute, or control code, and another conditioned on the undesired attribute, or anti control code. We find that GeDi gives stronger controllability than the state of the art method while also achieving generation speeds more than 30 times faster. Additionally, training GeDi on only four topics allows us to controllably generate new topics zero-shot from just a keyword, unlocking a new capability that previous controllable generation methods do not have. Lastly, we show that GeDi can make GPT-2 (1.5B parameters) significantly less toxic without sacrificing linguistic quality, making it by far the most practical existing method for detoxifying large language models while maintaining a fast generation speed.
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ទោះបីជាម៉ូដែលភាសាល្បឿនធំៗ (LMs) អាចចម្លងចែកចាយភាសាធម្មជាតិបានគ្រប់គ្រាន់ដើម្បីបង្កើតអត្ថបទដែលមើលទៅដូចជាពិតក៏ដោយ ក៏វាពិបាកក្នុងការគ្រប់គ្រងថាតើតំបន់ណាមួយនៃចែកចាយនោះដែលពួកវាបង្កើត។ នេះគឺជាបញ្ហាជាពិសេសដោយសារតែទិន្នន័យដែលប្រើសម្រាប់បណ្តុះបណ្តាល LMs ធំៗ ជាទូទៅមានភាពអាក្រក់ ភាពអ័ព្ទ អំពើលំអៀង និងភាពអវិជ្ជមានយ៉ាងខ្លាំង។ យើងស្នើ GeDi ជាវិធីសាស្ត្រដ៏មានប្រសិទ្ធភាពសម្រាប់ប្រើ LMs តូចៗជាអង្គភាពបែងចែកបង្កើត ដើម្បីដឹកនាំការបង្កើតពី LMs ធំៗ ដើម្បីធ្វើឱ្យពួកវាមានសុវត្ថិភាព និងគ្រប់គ្រងបានច្រើនជាងមុន។ GeDi ដឹកនាំការបង្កើតនៅរាល់ជំហានតាមរយៈការគណនាប្រូបាបប្រភេទសម្រាប់សញ្ញាបន្ទាប់ទាំងអស់ដែលអាចកើតមានតាមរយៈច្បាប់ប៉ៃយ៉េ ដោយធ្វើឱ្យមានលក្ខណៈធម្មតាលើចែកចាយលក្ខណៈពីរ មួយដែលអនុវត្តលើលក្ខណៈដែលចង់បាន ឬកូដគ្រប់គ្រង ហើយមួយទៀតដែលអនុវត្តលើលក្ខណៈដែលមិនចង់បាន ឬកូដប្រឆាំងគ្រប់គ្រង។ យើងរកឃើញថា GeDi ផ្តល់នូវការគ្រប់គ្រងបានខ្លាំងជាងវិធីសាស្ត្រដែលមានស្រាប់ ខណៈពេលដែលវាក៏សម្រេចបានល្បឿនបង្កើតលឿនជាង 30 ដង។ លើសពីនេះទៀត ការបណ្តុះបណ្តាល GeDi លើប្រធានបទតែបួនប្រធានបទ អនុញ្ញាតឱ្យយើងបង្កើតប្រធានបទថ្មីៗដោយគ្មានគំរូ ពីគ្រាប់ចុចមួយគ្រាប់ប៉ុណ្ណោះ ដែលបើកដំណើរការសមត្ថភាពថ្មីមួយដែលវិធីសាស្ត្របង្កើតដែលគ្រប់គ្រងបានមុនៗមិនមាន។ ចុងក្រោយ យើងបង្ហាញថា GeDi អាចធ្វើឱ្យ GPT-2 (1.5B ប៉ារ៉ាម៉ែត្រ) មានភាពអាក្រក់តិចជាងមុន ដោយមិនបាត់បង់គុណភាពភាសា ដែលធ្វើឱ្យវាក្លាយជាវិធីសាស្ត្រដែលអនុវត្តបានច្រើនបំផុតក្នុងចំណោមវិធីសាស្ត្រដែលមានស្រាប់សម្រាប់ធ្វើឱ្យម៉ូដែលភាសាធំៗមានសុវត្ថិភាព ខណៈពេលដែលរក្សាល្បឿនបង្កើតលឿន។
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The prompt optical emission of GRB 990123 was uncorrelated to the gamma-ray light-curve and exhibited temporal properties similar to those of the steeply-decaying, early X-ray emission observed by Swift at the end of many bursts. These facts suggest that the optical counterpart of GRB 990123 was the large-angle emission released during (the second pulse of) the burst. If the optical and gamma-ray emissions of GRB 990123 have, indeed, the same origin then their properties require that (i) the optical counterpart was synchrotron emission and the gamma-rays arose from inverse-Compton scatterings ("synchrotron self-Compton model"), (ii) the peak-energy of the optical-synchrotron component was at ~20 eV, and (iii) the burst emission was produced by a relativistic outflow moving at Lorentz factor > 450 and at a radius > 10^{15} cm, which is comparable to the outflow deceleration radius. Because the spectrum of GRB 990123 was optically thin above 2 keV, the magnetic field behind the shock must have decayed on a length-scale of <1% of the thickness of the shocked gas, which corresponds to 10^6-10^7 plasma skin-depths. Consistency of the optical counterpart decay rate and its spectral slope (or that of the burst, if they represent different spectral components) with the expectations for the large-angle burst emission represents the most direct test of the unifying picture proposed here for GRB 990123.
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Ang prompt na optical emission ng GRB 990123 ay hindi nauugnay sa gamma-ray light-curve at nagpakita ng mga temporal na katangian na katulad ng mga steeply-decaying, maagang X-ray emission na naitala ng Swift sa katapusan ng maraming pagsabog. Ang mga katotohanang ito ay nagmumungkahi na ang optical counterpart ng GRB 990123 ay ang large-angle emission na nailabas noong (ikalawang pulso ng) pagsabog. Kung ang optical at gamma-ray emissions ng GRB 990123 ay may iisang pinagmulan nga, kung gayon ang kanilang mga katangian ay nangangailangan na (i) ang optical counterpart ay synchrotron emission at ang gamma-ray ay nagmula sa inverse-Compton scatterings ("synchrotron self-Compton model"), (ii) ang peak-energy ng optical-synchrotron na bahagi ay nasa ~20 eV, at (iii) ang emission ng pagsabog ay nabuo ng isang relativistic outflow na gumalaw sa Lorentz factor na higit sa 450 at sa radius na higit sa 10^{15} cm, na katumbas ng outflow deceleration radius. Dahil ang spectrum ng GRB 990123 ay optically thin sa itaas ng 2 keV, ang magnetic field sa likod ng shock ay dapat nag-decay sa isang habang sukat na mas mababa sa 1% ng kapal ng nasugatang gas, na tumutugma sa 10^6-10^7 plasma skin-depths. Ang pagkakatugma ng decay rate ng optical counterpart at ng spectral slope nito (o ng pagsabog, kung sila ay kumakatawan sa iba't ibang spectral component) sa mga inaasahan para sa large-angle burst emission ang siyang pinakadirektang pagsusuri sa nag-iisang larawan na ipinapangako rito para sa GRB 990123.
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On November 23, 2021, the Einstein-Besso manuscript on the perihelion motion of Mercury will be auctioned at Christie's. Expected to fetch around $3M, it promises to be the most expensive scientific manuscript ever sold at auction. In this preprint, we present the parts of our forthcoming book, How Einstein Found His Field Equations. Sources and Interpretation (Springer, 2021) dealing with Einstein's attempts, in 1913 and in 1915, to account for the anomalous advance of Mercury's perihelion. In 1913, as documented in the Einstein-Besso manuscript, Einstein and his friend Michele Besso found that the Einstein-Grossmann or Entwurf (= outline or draft) theory, a preliminary version of general relativity, could only account for 18 of the 43 seconds-of-arc-per-century discrepancy between Newtonian theory and observation. In November 1915, however, putting the techniques developed in his collaboration with Besso to good use, Einstein showed that his new general theory of relativity could account for all missing 43 seconds of arc. After a brief introduction, we provide an annotated transcription of the key pages of the Einstein-Besso manuscript and an annotated new translation of the November 1915 perihelion paper.
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၂၀၂၁ ခုနှစ်၊ နိုဝင်ဘာလ ၂၃ ရက်နေ့တွင် မာကျူရီဂြိုဟ်၏ နေအနီးဆုံးအမှတ် ရွေ့လျားမှုနှင့်ပတ်သက်သော အိုင်းစတိုင်း-ဘက်ဆို မူရင်းစာရွက်များကို ခရစ္စတီးကရိပ်တွင် လေလံခတ်မည်ဖြစ်သည်။ အလျားလိုက် ၃ သန်းခန့်ရရှိမည်ဟု မျှော်လင့်ထားပြီး လေလံခေါ်ရောင်းချမည့် သိပ္ပံနည်းကျ မူရင်းစာရွက်များအနက် အကုန်အကျအများဆုံးဖြစ်လာမည်ဟု မျှော်လင့်ရသည်။ ဤကြိုတင်ထုတ်ဝေမှုတွင် ကျွန်ုပ်တို့၏ မကြာမီထွက်ရှိမည့်စာအုပ်ဖြစ်သော အိုင်းစတိုင်းသည် သူ၏ကွင်းညီများကို မည်သို့ရှာဖွေခဲ့သနည်း။ မူရင်းအရင်းအမြစ်များနှင့် အနက်ကောက်ယူမှုများ (စပရင်ဂါ၊ ၂၀၂၁) မှ မာကျူရီဂြိုဟ်၏ နေအနီးဆုံးအမှတ် အလွဲသွားသော ရှေ့ဆက်တိုးတက်မှုကို ၁၉၁၃ ခုနှစ်နှင့် ၁၉၁၅ ခုနှစ်တို့တွင် အိုင်းစတိုင်းကြိုးပမ်းခဲ့ပုံများကို တင်ပြထားသည်။ ၁၉၁၃ ခုနှစ်တွင် အိုင်းစတိုင်း-ဘက်ဆို မူရင်းစာရွက်များတွင် မှတ်တမ်းတင်ထားသည့်အတိုင်း အိုင်းစတိုင်းနှင့် သူ၏မိတ်ဆွေ မိုက်ချယ်လ် ဘက်ဆိုတို့သည် ယေဘုယျ ဆွဲငင်အားဆိုင်ရာ သီအိုရီ၏ ကနဦးဗားရှင်းဖြစ်သော အိုင်းစတိုင်း-ဂရော့စ်မန်း သို့မဟုတ် အင်တွာ့ဖ် (= မူကွဲ သို့မဟုတ် ကြိုတင်မူကွဲ) သီအိုရီကို အသုံးပြု၍ နယူတန်၏သီအိုရီနှင့် လေ့လာမှုအကြား တစ်ရာစုလျှင် စက္ကန့် ၄၃ ပိုင်းခွဲ ကွာခြားမှုအနက် စက္ကန့် ၁၈ ပိုင်းခွဲသာ ရှင်းပြနိုင်ကြောင်း တွေ့ရှိခဲ့ကြသည်။ သို့ရာတွင် ၁၉၁၅ ခုနှစ် နိုဝင်ဘာလတွင် ဘက်ဆိုနှင့် ပူးပေါင်းကာ ဖွံ့ဖြိုးတိုးတက်စေခဲ့သော နည်းလမ်းများကို အကျိုးရှိစွာ အသုံးချကာ အိုင်းစတိုင်းသည် သူ၏ ယေဘုယျ ဆွဲငင်အားဆိုင်ရာ သီအိုရီသစ်ဖြင့် ပျောက်ဆုံးနေသော စက္ကန့် ၄၃ ပိုင်းခွဲအားလုံးကို ရှင်းပြနိုင်ကြောင်း ပြသခဲ့သည်။ အကျဉ်းချုပ် မိတ်ဆက်ချက်အပြီးတွင် အိုင်းစတိုင်း-ဘက်ဆို မူရင်းစာရွက်များ၏ အဓိကစာမျက်နှာများကို မှတ်စုဖြင့်တွဲဖက်ထားသော မှတ်တမ်းတင်မှုနှင့် နိုဝင်ဘာ ၁၉၁၅ ခုနှစ်က နေအနီးဆုံးအမှတ် စာတမ်းကို မှတ်စုဖြင့်တွဲဖက်ထားသော မူလဘာသာပြန်သစ်ကို ပေးအပ်ထားပါသည်။
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my
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Let R be the set of isomorphism classes of ideals in the Weyl algebra $A=A_{1}$, and let C be the set of isomorphism classes of triples (V; X, Y), where V is a finite-dimensional (complex) vector space, and X, Y are endomorphisms of V such that [X,Y]+I has rank 1. Following a suggestion of L. Le Bruyn, we define a map $\theta: R \to C$ by appropriately extending an ideal of A to a sheaf over a quantum projective plane, and then using standard methods of homological algebra. We prove that $\theta$ is inverse to a bijection $\omega: C \to R$ constructed in \cite{BW} by a completely different method. The main step in the proof is to show that $\theta$ is equivariant with respect to natural actions of the group G=Aut(A) on R and C: for that we have to study also the extensions of an ideal to certain weighted quantum projective planes. Along the way, we find an elementary description of \theta.
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Payagan ang R na maging hanay ng mga klase ng isomorphism ng mga ideal sa alhebrang Weyl $A=A_{1}$, at payagan ang C na maging hanay ng mga klase ng isomorphism ng mga triple (V; X, Y), kung saan ang V ay isang may hangganang-dimensyonal (kompleks) na espasyong bektor, at ang X, Y ay mga endomorphism ng V kung saan ang [X,Y]+I ay may ranggo na 1. Sumusunod sa isang iminungkahing kay L. Le Bruyn, inilalarawan namin ang isang paglilipat $\theta: R \to C$ sa pamamagitan ng angkop na pagpapalawig ng isang ideal ng A sa isang sheaf sa ibabaw ng isang quantum na planong proyektibo, at pagkatapos ay gumagamit ng karaniwang pamamaraan ng homological na alhebra. Pinatutunayan namin na ang $\theta$ ay kabaligtaran ng isang bijeksyon $\omega: C \to R$ na itinayo sa \cite{BW} sa pamamagitan ng isang ganap na iba't ibang pamamaraan. Ang pangunahing hakbang sa patunay ay ipakita na ang $\theta$ ay equivariant kaugnay ng mga likas na aksyon ng grupo G=Aut(A) sa R at C: para doon, kailangan din naming pag-aralan ang mga pagpapalawig ng isang ideal sa ilang partikular na may-timbang na quantum na mga planong proyektibo. Sa pagitan, natagpuan namin ang isang pang-elementong deskripsyon ng \theta.
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tl
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We present a large sample of infrared-luminous candidate active galactic nuclei (AGNs) that lack X-ray detections in Chandra, XMM-Newton, and NuSTAR fields. We selected all optically detected SDSS sources with redshift measurements, combined additional broadband photometry from WISE, UKIDSS, 2MASS, and GALEX, and modeled the spectral energy distributions (SEDs) of our sample sources. We parameterize nuclear obscuration in our SEDs with $E(B\!-\!V)_{\text{AGN}}$ and uncover thousands of powerful obscured AGNs that lack X-ray counterparts, many of which are identified as AGN candidates based on straightforward WISE photometric criteria. Using the observed luminosity correlation between restframe 2-10 keV ($L_{\text{X}}$) and restframe AGN 6 $\mu{\text{m}}$ ($L_{\text{MIR}}$), we estimate the intrinsic X-ray luminosities of our sample sources and combine these data with flux limits from X-ray catalogs to determine lower limits on nuclear obscuration. Using the ratio of intrinsic-to-observed X-ray luminosity ($R_{L_{\text{X}}}$), we find a significant fraction of sources with column densities approaching $N_{\text{H}}>$ 10$^{\text{24}}$ cm$^{-{\text{2}}}$, suggesting that multiwavelength observations are necessary to account for the population of heavily obscured AGNs. We simulate the underlying $N_{\text{H}}$ distribution for the X-ray non-detected sources in our sample through survival analysis, and confirm the presence of AGN activity via X-ray stacking. Our results point to a considerable population of extremely obscured AGNs undetected by current X-ray observatories.
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ہم انفراریڈ روشن امیدوار فعال سَیاروی ہستیوں (ای جی این ایز) کا ایک بڑا نمونہ پیش کرتے ہیں جن میں چاندرہ، ایکس ایم ایم نیوٹن اور نو اسٹار کے میدانوں میں ایکس رے کا کوئی انکشاف نہیں ہوتا۔ ہم نے سپیکٹرو سکوپک سروے کے تمام نظری طور پر دریافت شدہ ذرائع کو سرخ فاصلہ کے پیمائش کے ساتھ منتخب کیا، وائیس، یو کے آئی ڈی ایس ایس، 2ایم اے ایم ایس اور گیلیکس سے مزید وسیع پیمانے پر فوٹومیٹری شامل کی، اور اپنے نمونہ ذرائع کے سپیکٹرل انرجی تقسیم (ایس ای ڈی) کی ماڈلنگ کی۔ ہم اپنے ایس ای ڈی میں نیوکلیئر پردہ داری کی وضاحت $E(B\!-\!V)_{\text{AGN}}$ کے ذریعہ کرتے ہیں اور ہزاروں طاقتور پردہ دار ای جی این ایز کو دریافت کرتے ہیں جن کے ایکس رے کے ہم منصبدار نہیں ہوتے، جن میں سے بہت سے صرف وائیس فوٹومیٹری معیارات کی بنیاد پر ای جی این ای امیدوار کے طور پر شناخت کیے گئے ہیں۔ باقی 2-10 کے وی ($L_{\text{X}}$) اور باقی ای جی این ای 6 $\mu{\text{m}}$ ($L_{\text{MIR}}$) کے درمیان مشاہدہ شدہ روشنی کے تعلق کا استعمال کرتے ہوئے، ہم اپنے نمونہ ذرائع کی ذاتی ایکس رے روشنی کا اندازہ لگاتے ہیں اور ان ڈیٹا کو ایکس رے کیٹلاگز کے پار ہونے کی حد کے ساتھ ملاتے ہیں تاکہ نیوکلیئر پردہ داری کی کم از کم حد معلوم کی جا سکے۔ ذاتی اور مشاہدہ شدہ ایکس رے روشنی کے تناسب ($R_{L_{\text{X}}}$) کا استعمال کرتے ہوئے، ہم ایسے ذرائع کی ایک قابل ذکر تعداد کو تلاش کرتے ہیں جن کے کالم کی کثافت $N_{\text{H}}>$ 10$^{\text{24}}$ cm$^{-{\text{2}}}$ کی طرف بڑھ رہی ہوتی ہے، جس سے ظاہر ہوتا ہے کہ شدید پردہ دار ای جی این ایز کی آبادی کو شامل کرنے کے لیے متعدد طول موج کی مشاہدات ضروری ہیں۔ ہم اپنے نمونہ میں ایکس رے کی عدم دریافت شدہ ذرائع کے لیے بنیادی $N_{\text{H}}$ تقسیم کی شبیہ کشی بقا تجزیہ کے ذریعہ کرتے ہیں، اور ایکس رے اسٹیکنگ کے ذریعہ ای جی این ای سرگرمی کی موجودگی کی تصدیق کرتے ہیں۔ ہمارے نتائج اس بات کی طرف اشارہ کرتے ہیں کہ موجودہ ایکس رے رصد گاہوں کے ذریعہ دریافت نہ ہونے والے انتہائی پردہ دار ای جی این ایز کی ایک قابل ذکر آبادی موجود ہے۔
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ur
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We employ the Schwinger boson mean-field approach to study the effects of arbitrary frustrated bonds and plaquettes (formed from four frustrated bonds) in two-dimensional ferro- and antiferromagnets on the spin-wave spectrum and the correlation length at finite temperatures. We distinguish between strongly frustrated bonds (plaquettes), when the frustrated coupling $J^\prime$ exceeds the spin canting threshold $J_c$, and weakly frustrated bonds (plaquettes), with $J^\prime <J_c, (J_c-J^\prime)/J_c\sim 1$. It is shown that in antiferromagnets the amplitude of spin-wave scattering on strongly frustrated bonds or plaquettes grows with the decrease of the temperature. A small amount of such defects reduces significantly the spin-wave stiffness and the correlation length at low temperatures. As a result, the quasi-2D N\'eel temperature is sharply suppressed. Quantum fluctuations are also considered and their effect on the spin-wave spectrum is shown to be of the order of $(2S)^{-2}\ln^{-1}2S$ in the large spin limit. For weakly frustrated (nonfrustrated) defect bonds (plaquettes) the spin-wave stiffness renormalization is of the order of the dopant concentration and does not depend on the temperature. The results account for the observed properties of doped quasi-2D $La_2CuO_{4+x}$.
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Kami menggunakan pendekatan medan purata boson Schwinger untuk mengkaji kesan ikatan terpenun dan petak-petak (yang terbentuk daripada empat ikatan terpenun) yang sewenang-wenang dalam ferromagnet dan antiferromagnet dua dimensi terhadap spektrum gelombang spin dan panjang berkorelasi pada suhu terhingga. Kami membezakan antara ikatan terpenun (petak-petak) yang sangat kuat, apabila pasangan terpenun $J^\prime$ melebihi ambang kecondongan spin $J_c$, dan ikatan terpenun (petak-petak) yang lemah, dengan $J^\prime <J_c, (J_c-J^\prime)/J_c\sim 1$. Ditunjukkan bahawa dalam antiferromagnet, amplitud serakan gelombang spin pada ikatan atau petak yang sangat terpenun bertambah dengan penurunan suhu. Jumlah kecil cacat sedemikian mengurangkan secara ketara kekukuhan gelombang spin dan panjang berkorelasi pada suhu rendah. Akibatnya, suhu N\'eel quasi-2D ditekan secara mendadak. Fluktuasi kuantum turut dipertimbangkan dan kesannya terhadap spektrum gelombang spin ditunjukkan berada dalam tertib $(2S)^{-2}\ln^{-1}2S$ dalam had spin besar. Bagi ikatan cacat (petak-petak) yang terpenun lemah (tidak terpenun), pembetulan kekukuhan gelombang spin adalah dalam tertib kepekatan pendopan dan tidak bergantung kepada suhu. Keputusan ini menerangkan sifat-sifat yang dicerap dalam $La_2CuO_{4+x}$ quasi-2D yang didop.
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ms
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We investigate dust entrainment by photoevaporative winds in protoplanetary discs using dusty smoothed particle hydrodrodynamics (SPH). We use unequal-mass particles to resolve more than five orders of magnitude in disc/outflow density and a one-fluid formulation to efficiently simulate an equivalent magnitude range in drag stopping time. We find that only micron sized dust grains and smaller can be entrained in EUV driven winds. The maximum grain size is set by dust settling in the disc rather than aerodynamic drag in the wind. More generally, there is a linear relationship between the base flow density and the maximum entrainable grain size in the wind. A pileup of micron sized dust grains can occur in the upper atmosphere at critical radii in the disc as grains decouple from the low-density wind. Entrainment is a strong function of location in the disc, resulting in a size sorting of grains in the outflow---the largest grain being carried out between $10$--$20\,$AU. The peak dust density for each grain size occurs at the inner edge of its own entrainment region.
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우리는 성운 원반에서 광증발성 바람에 의한 먼지 혼입 현상을 먼지가 포함된 평활입자유체역학(SPH)을 사용하여 조사한다. 원반/유출 밀도에서 5차 이상의 크기 범위를 해석하기 위해 불균등한 질량을 가진 입자를 사용하였으며, 드래그 정지 시간의 동등한 크기 범위를 효율적으로 시뮬레이션하기 위해 일체유체(one-fluid) 공식을 적용하였다. 우리는 EUV에 의해 유도된 바람에서는 미크론 크기 이하의 먼지 입자만이 혼입될 수 있음을 발견하였다. 최대 입자 크기는 바람 내 공기역학적 드래그보다는 원반 내 먼지 침강에 의해 결정된다. 보다 일반적으로, 바람 내에서 혼입 가능한 최대 입자 크기와 기저 유동 밀도 사이에는 선형 관계가 존재한다. 입자들이 저밀도 바람으로부터 분리되면서, 원반의 임계 반경에서 상층 대기부에 미크론 크기의 먼지 입자들이 축적될 수 있다. 혼입은 원반 내 위치에 따라 크게 달라지며, 이로 인해 유출 내에서 입자 크기별로 정렬되는 현상이 발생하는데, 가장 큰 입자는 $10$–$20\,$AU 사이에서 유출된다. 각 입자 크기에 대한 최대 먼지 밀도는 각자의 혼입 영역의 내부 경계에서 발생한다.
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ko
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Over cosmic time, galaxies grow through the hierarchical merging of smaller galaxies. However, the bright region of the galaxy luminosity function is incompatible with the simplest version of hierarchical merging, and it is believed that feedback from the central black hole in the host galaxies reduces the number of bright galaxies and regulates the co-evolution of black hole and host galaxy. Numerous simulations of galaxy evolution have attempted to include the physical effects of such feedback with a resolution usually exceeding a kiloparsec. However, interactions between jets and the interstellar medium involve processes occurring on less than kiloparsec scales. In order to further the understanding of processes occurring on such scales, we present a suite of simulations of relativistic jets interacting with a fractal two-phase interstellar medium with a resolution of two parsecs and a largest scale of one kiloparsec. The transfer of energy and momentum to the interstellar medium is considerable, and we find that jets with powers in the range of 10^43-10^46 erg s^-1 can inhibit star formation through the dispersal of dense gas in the galaxy core. We determine the effectiveness of this process as a function of the ratio of the jet power to the Eddington luminosity of the black hole, the pressure of the interstellar medium and the porosity of the dense gas.
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মহাজাগতিক সময়ের মধ্য দিয়ে ছোট ছোট ছায়াপথের পদানুক্রমিক সংযুক্তির মাধ্যমে ছায়াপথগুলি বৃদ্ধি পায়। তবে ছায়াপথের দীপ্তি অপেক্ষকের উজ্জ্বল অংশটি পদানুক্রমিক সংযুক্তির সরলতম সংস্করণের সাথে অসামঞ্জস্যপূর্ণ, এবং এটি বিশ্বাস করা হয় যে আশ্রয়কারী ছায়াপথগুলির কেন্দ্রীয় কৃষ্ণগহ্বর থেকে উৎসরিত প্রতিক্রিয়া উজ্জ্বল ছায়াপথের সংখ্যা হ্রাস করে এবং কৃষ্ণগহ্বর ও আশ্রয়কারী ছায়াপথের সহ-বিবর্তনকে নিয়ন্ত্রণ করে। ছায়াপথের বিবর্তনের অসংখ্য সিমুলেশন সাধারণত এক কিলোপারসেকের বেশি রেজোলিউশন নিয়ে এমন প্রতিক্রিয়ার ভৌত প্রভাব অন্তর্ভুক্ত করার চেষ্টা করেছে। তবুও, জেট এবং আন্তঃনাক্ষত্রিক মাধ্যমের মধ্যে মিথস্ক্রিয়া এক কিলোপারসেকের কম স্কেলে ঘটিত প্রক্রিয়াগুলির সাথে জড়িত। এমন স্কেলে ঘটিত প্রক্রিয়াগুলি সম্পর্কে আরও ভালোভাবে বোঝার জন্য, আমরা দুই পারসেক রেজোলিউশন এবং এক কিলোপারসেক পর্যন্ত সর্বোচ্চ স্কেল নিয়ে একটি ফ্র্যাকটাল দ্বিপর্যায় আন্তঃনাক্ষত্রিক মাধ্যমের সাথে আপেক্ষিকতাজনিত জেটগুলির মিথস্ক্রিয়ার সিমুলেশনের একটি সেট উপস্থাপন করি। আন্তঃনাক্ষত্রিক মাধ্যমে শক্তি ও ভরবেগের স্থানান্তর উল্লেখযোগ্য, এবং আমরা দেখতে পাই যে 10^43-10^46 আর্গ সেকেন্ড^-1 পরিসরের ক্ষমতা বিশিষ্ট জেটগুলি ছায়াপথের কেন্দ্রে ঘন গ্যাস ছড়িয়ে দেওয়ার মাধ্যমে তারকা গঠনকে বাধা দিতে পারে। আমরা জেটের ক্ষমতা এবং কৃষ্ণগহ্বরের এডিংটন দীপ্তির অনুপাত, আন্তঃনাক্ষত্রিক মাধ্যমের চাপ এবং ঘন গ্যাসের সরুত্বের উপর ভিত্তি করে এই প্রক্রিয়ার কার্যকারিতা নির্ধারণ করি।
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bn
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We perform numerical simulations of a two-dimensional bidisperse granular packing subjected to both a static confining pressure and a sinusoidal dynamic forcing applied by a wall on one edge of the packing. We measure the response experienced by a wall on the opposite edge of the packing and obtain the resonant frequency of the packing as the static or dynamic pressures are varied. Under increasing static pressure, the resonant frequency increases, indicating a velocity increase of elastic waves propagating through the packing. In contrast, when the dynamic amplitude is increased for fixed static pressure, the resonant frequency decreases, indicating a decrease in the wave velocity. This occurs both for compressional and for shear dynamic forcing, and is in agreement with experimental results. We find that the average contact number $Z_c$ at the resonant frequency decreases with increasing dynamic amplitude, indicating that the elastic softening of the packing is associated with a reduced number of grain-grain contacts through which the elastic waves can travel. We image the excitations created in the packing and show that there are localized disturbances or soft spots that become more prevalent with increasing dynamic amplitude. Our results are in agreement with experiments on glass bead packings and earth materials such as sandstone and granite, and may be relevant to the decrease in elastic wave velocities that has been observed to occur near fault zones after strong earthquakes, in surficial sediments during strong ground motion, and in structures during earthquake excitation.
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Realizamos simulações numéricas de um empacotamento granular bidisperso bidimensional submetido a uma pressão de confinamento estática e a uma força dinâmica senoidal aplicada por uma parede em uma das bordas do empacotamento. Medimos a resposta experimentada por uma parede na borda oposta do empacotamento e obtemos a frequência de ressonância do empacotamento à medida que as pressões estática ou dinâmica são variadas. Com o aumento da pressão estática, a frequência de ressonância aumenta, indicando um aumento na velocidade de ondas elásticas que se propagam através do empacotamento. Em contraste, quando a amplitude dinâmica é aumentada para uma pressão estática fixa, a frequência de ressonância diminui, indicando uma redução na velocidade da onda. Isso ocorre tanto para forçamento dinâmico compressional quanto para forçamento de cisalhamento, e está de acordo com resultados experimentais. Descobrimos que o número médio de contatos \(Z_c\) na frequência de ressonância diminui com o aumento da amplitude dinâmica, indicando que o amolecimento elástico do empacotamento está associado a um número reduzido de contatos entre grãos pelos quais as ondas elásticas podem se propagar. Visualizamos as excitações geradas no empacotamento e mostramos que existem perturbações localizadas ou pontos moles que se tornam mais prevalentes com o aumento da amplitude dinâmica. Nossos resultados estão de acordo com experimentos realizados em empacotamentos de microesferas de vidro e materiais terrestres como arenito e granito, e podem ser relevantes para a diminuição das velocidades das ondas elásticas observada em zonas próximas a falhas após terremotos fortes, em sedimentos superficiais durante movimentos fortes do solo e em estruturas durante excitação sísmica.
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pt
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When there exists a malicious attacker in the network, we need to consider the possibilities of eavesdropping and the contamination simultaneously. Under an acyclic broadcast network, the optimality of linear codes was shown when Eve is allowed to attack any $r$ edges. The optimality of linear codes is not shown under a different assumption for Eve. As a typical example of an acyclic unicast network, we focus on the one-hop relay network under the single transmission scheme by assuming that Eve attacks only one edge in each level. Surprisingly, as a result, we find that a non-linear code significantly improves the performance on the one-hop relay network over linear codes. That is, a non-liner code realizes the imperfect security on this model that cannot be realized by linear codes. This kind of superiority of a linear code still holds even with considering the effect of sequential error injection on information leakage.
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ເມື່ອມີຜູ້ໂຈມຕີທີ່ມີເຈດຕະນາຮ້າຍໃນເຄືອຂ່າຍ, ພວກເຮົາຈຳເປັນຕ້ອງພິຈາລະນາຄວາມເປັນໄປໄດ້ຂອງການດັກຟັງ ແລະ ການປົນເປື້ອນພ້ອມກັນ. ໃນເຄືອຂ່າຍຖ່າຍໂທລະສາບທີ່ບໍ່ມີວົງຈອນ, ຄວາມເປັນທີ່ດີທີ່ສຸດຂອງລະຫັດເສັ້ນຊື່ໄດ້ຖືກສະແດງໃຫ້ເຫັນເມື່ອ Eve ໄດ້ຮັບອະນຸຍາດໃຫ້ໂຈມຕີທຸກໆ $r$ ແຖວ. ຄວາມເປັນທີ່ດີທີ່ສຸດຂອງລະຫັດເສັ້ນຊື່ຍັງບໍ່ໄດ້ຖືກສະແດງໃນຂໍ້ສົມມຸດຖານອື່ນໆຂອງ Eve. ເປັນຕົວຢ່າງທົ່ວໄປຂອງເຄືອຂ່າຍ unicast ທີ່ບໍ່ມີວົງຈອນ, ພວກເຮົາມຸ່ງເນັ້ນໄປທີ່ເຄືອຂ່າຍ relay ຫນຶ່ງຂັ້ນພາຍໃຕ້ແຜນການຖ່າຍໂທລະສາບດຽວໂດຍສົມມຸດວ່າ Eve ໂຈມຕີພຽງແຖວດຽວໃນແຕ່ລະຂັ້ນ. ຢ່າງຫນ້າປະຫລາດໃຈ, ຜົນໄດ້ຮັບພວກເຮົາພົບວ່າລະຫັດທີ່ບໍ່ແມ່ນເສັ້ນຊື່ປັບປຸງປະສິດທິພາບຢ່າງຫຼວງຫຼາຍໃນເຄືອຂ່າຍ relay ຫນຶ່ງຂັ້ນເມື່ອທຽບກັບລະຫັດເສັ້ນຊື່. ນັ້ນກໍຄື, ລະຫັດທີ່ບໍ່ແມ່ນເສັ້ນຊື່ສາມາດບັນລຸຄວາມປອດໄພທີ່ບໍ່ສົມບູນໃນຮູບແບບນີ້ ເຊິ່ງບໍ່ສາມາດບັນລຸໄດ້ໂດຍລະຫັດເສັ້ນຊື່. ຄວາມເອກະສິດຂອງລະຫັດເສັ້ນຊື່ແບບນີ້ຍັງຄົງຢູ່ເຖິງແມ່ນວ່າຈະພິຈາລະນາຜົນກະທົບຂອງການສອດແນມຂໍ້ມູນຕິດຕໍ່ກັນຕໍ່ການຮົ່ວໄຫຼຂອງຂໍ້ມູນ.
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lo
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In this paper, we analyze a composite decode-and-forward scheme for the two-way relay channel with a direct link. During transmission, our scheme combines both block Markov coding and an independent coding scheme similar to network coding at the relay. The main contribution of this work is to examine how link state impacts the allocation of power between these two distinct techniques, which in turn governs the necessity of each technique in achieving the largest transmission rate region. We analytically determine the link-state regimes and associated relaying techniques. Our results illustrate an interesting trend: when the user-to-relay link is marginally stronger than the direct link, it is optimal to use only independent coding. In this case, the relay need not use full power. However, for larger user-to-relay link gains, the relay must supplement independent coding with block Markov coding to achieve the largest rate region. These link-state regimes are important for the application of two-way relaying in 5G networks, such as in D2D mode or relay-aided transmission.
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In dieser Arbeit analysieren wir ein zusammengesetztes Decode-and-Forward-Verfahren für den bidirektionalen Relaiskanal mit direkter Verbindung. Während der Übertragung kombiniert unser Verfahren Block-Markov-Codierung und ein unabhängiges Codierungsverfahren, das der Netzwerkcodierung am Relais ähnelt. Der Hauptbeitrag dieser Arbeit besteht darin, zu untersuchen, wie der Zustand der Verbindung die Aufteilung der Sendeleistung zwischen diesen beiden unterschiedlichen Techniken beeinflusst, was wiederum bestimmt, inwieweit jede Technik notwendig ist, um den größtmöglichen Übertragungsratebereich zu erreichen. Wir ermitteln analytisch die Zustandsbereiche der Verbindungen und die zugehörigen Relaisverfahren. Unsere Ergebnisse zeigen eine interessante Tendenz: Wenn die Benutzer-zu-Relais-Verbindung geringfügig stärker ist als die direkte Verbindung, ist es optimal, ausschließlich unabhängige Codierung zu verwenden. In diesem Fall muss das Relais nicht die volle Leistung nutzen. Bei größeren Gewinnen der Benutzer-zu-Relais-Verbindung muss das Relais jedoch die unabhängige Codierung durch Block-Markov-Codierung ergänzen, um den größtmöglichen Ratenbereich zu erreichen. Diese Zustandsbereiche der Verbindungen sind wichtig für die Anwendung des bidirektionalen Relaisbetriebs in 5G-Netzen, beispielsweise im D2D-Modus oder bei relaisunterstützter Übertragung.
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de
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In the setting of a Gaussian channel without power constraints, proposed by Poltyrev, the codewords are points in an n-dimensional Euclidean space (an infinite constellation) and the tradeoff between their density and the error probability is considered. The capacity in this setting is the highest achievable normalized log density (NLD) with vanishing error probability. This capacity as well as error exponent bounds for this setting are known. In this work we consider the optimal performance achievable in the fixed blocklength (dimension) regime. We provide two new achievability bounds, and extend the validity of the sphere bound to finite dimensional infinite constellations. We also provide asymptotic analysis of the bounds: When the NLD is fixed, we provide asymptotic expansions for the bounds that are significantly tighter than the previously known error exponent results. When the error probability is fixed, we show that as n grows, the gap to capacity is inversely proportional (up to the first order) to the square-root of n where the proportion constant is given by the inverse Q-function of the allowed error probability, times the square root of 1/2. In an analogy to similar result in channel coding, the dispersion of infinite constellations is 1/2nat^2 per channel use. All our achievability results use lattices and therefore hold for the maximal error probability as well. Connections to the error exponent of the power constrained Gaussian channel and to the volume-to-noise ratio as a figure of merit are discussed. In addition, we demonstrate the tightness of the results numerically and compare to state-of-the-art coding schemes.
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گاوسی چینل کے اس تناظر میں جس میں طاقت کی کوئی حد نہیں ہوتی، جو پولٹیریف کے ذریعہ تجویز کیا گیا تھا، کوڈلفاظ n-بُعدی یوقلڈی فضا میں نقاط ہوتے ہیں (امحدود تراکیب) اور ان کی کثافت اور غلطی کے امکان کے درمیان تعلق کا جائزہ لیا جاتا ہے۔ اس تنظیم میں صلاحیت سے مراد غیر معمولی غلطی کے امکان کے ساتھ حاصل کی جا سکنے والی زیادہ سے زیادہ نارملائزڈ لاگ کثافت (NLD) ہے۔ اس صلاحیت کے علاوہ اس تنظیم کے لیے غلطی کے اُسّی حدود بھی معلوم ہیں۔ اس کام میں ہم فکسڈ بلاک لمبائی (بُعد) کے دائرہ کار میں حاصل کی جا سکنے والی بہترین کارکردگی پر غور کرتے ہیں۔ ہم دو نئی حصولیت کی حدود فراہم کرتے ہیں، اور سفیر باؤنڈ کی وضاحت کو محدود بُعدی امحدود تراکیب تک وسعت دیتے ہیں۔ ہم حدود کا متشکل تجزیہ بھی فراہم کرتے ہیں: جب NLD کو فکسڈ رکھا جاتا ہے، تو ہم ایسے متشکل توسیعات فراہم کرتے ہیں جو پہلے سے معلوم غلطی کے اُسّی نتائج کے مقابلے میں کافی زیادہ مضبوط ہوتے ہیں۔ جب غلطی کا امکان فکسڈ ہو، تو ہم دکھاتے ہیں کہ جیسے جیسے n بڑھتا ہے، صلاحیت سے فرق n کی مربع جڑ کے الٹ تناسب پر منحصر ہوتا ہے (پہلے درجے تک)، جہاں تناسب کا دائمی عدد مجاز غلطی کے امکان کا معکوس Q-فنکشن ہوتا ہے، جسے 1/2 کی مربع جڑ سے ضرب دیا جاتا ہے۔ چینل کوڈنگ میں اسی قسم کے نتیجے کی طرح، امحدود تراکیب کی تقسیم 1/2 نیٹ² فی چینل استعمال ہوتی ہے۔ تمام حصولیت کے نتائج جالیوں کا استعمال کرتے ہیں اور اس لیے زیادہ سے زیادہ غلطی کے امکان کے لیے بھی درست ہوتے ہیں۔ طاقت پابندی والے گاوسی چینل کے غلطی کے اُسّی اور نویز تناسب کے حوالے سے حجم کو فائدہ مندی کے معیار کے طور پر تعلق پر بحث کی گئی ہے۔ اس کے علاوہ، ہم نتائج کی تنگی کو عددی طور پر ظاہر کرتے ہیں اور ان کا موازنہ موجودہ دور کی کوڈنگ اسکیموں سے کرتے ہیں۔
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ur
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We study the response of confining gauge theory to the external electric field by using holographic Yang-Mills theories in the large $N_c$ limit. Although the theories are in the confinement phase, we find a transition from the insulator to the conductor phase when the electric field exceeds its critical value. Then, the baryon number current is generated in the conductor phase. At the same time, in this phase, the meson melting is observed through the quasi-normal modes of meson spectrum. Possible ideas are given for the string state corresponding to the melted mesons, and they lead to the idea that the source of this current may be identified with the quarks and anti-quarks supplied by the melted mesons. We also discuss about other possible carriers. Furthermore, from the analysis of the massless quark, chiral symmetry restoration is observed at the insulator-conductor transition point by studying a confining theory in which the chiral symmetry is broken.
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Pinag-aaralan natin ang tugon ng confining gauge theory sa panlabas na electric field sa pamamagitan ng paggamit ng holographic na mga teorya ng Yang-Mills sa hangganan ng malaking $N_c$. Bagaman ang mga teorya ay nasa yugto ng confinement, natagpuan natin ang isang transisyon mula sa insulator tungo sa conductor phase kapag ang electric field ay lumampas sa kritikal nitong halaga. Pagkatapos, ang baryon number current ay nabubuo sa loob ng conductor phase. Kasabay nito, sa yugtong ito, ang pagkatunaw ng meson ay napagmasdan sa pamamagitan ng mga quasi-normal mode ng meson spectrum. Iba't ibang posibleng ideya ang ibinigay para sa string state na tumutugma sa mga natunaw na meson, at ito ay humahantong sa ideya na ang pinagmulan ng kasalukuyang ito ay maaaring maiugnay sa mga quark at anti-quark na ibinibigay ng mga natunaw na meson. Pinag-uusapan din natin ang tungkol sa iba pang posibleng mga tagapagdala. Bukod dito, mula sa pagsusuri sa massless na quark, ang pagbabalik ng chiral symmetry ay napagmasdan sa punto ng transisyon ng insulator-conductor sa pamamagitan ng pag-aaral ng isang confining theory kung saan nababali ang chiral symmetry.
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tl
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In this paper, we analyze a composite decode-and-forward scheme for the two-way relay channel with a direct link. During transmission, our scheme combines both block Markov coding and an independent coding scheme similar to network coding at the relay. The main contribution of this work is to examine how link state impacts the allocation of power between these two distinct techniques, which in turn governs the necessity of each technique in achieving the largest transmission rate region. We analytically determine the link-state regimes and associated relaying techniques. Our results illustrate an interesting trend: when the user-to-relay link is marginally stronger than the direct link, it is optimal to use only independent coding. In this case, the relay need not use full power. However, for larger user-to-relay link gains, the relay must supplement independent coding with block Markov coding to achieve the largest rate region. These link-state regimes are important for the application of two-way relaying in 5G networks, such as in D2D mode or relay-aided transmission.
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في هذا البحث، نقوم بتحليل نظام مركب لإعادة الترميز وإعادة الإرسال في قناة الترحيل ثنائية الاتجاه التي تتضمن اتصالاً مباشراً. أثناء الإرسال، يدمج نظامنا ترميز بلوكي من نوع ماركوف ونظام ترميز مستقل يشبه الترميز الشبكي في وحدة الترحيل. يكمن المساهمة الرئيسية لهذا العمل في دراسة تأثير حالة الاتصال على توزيع القدرة بين هاتين التقنيتين المختلفتين، والتي بدورها تحدد ضرورة استخدام كل تقنية لتحقيق أكبر منطقة ممكنة من معدلات الإرسال. قمنا بتحديد أنماط حالات الاتصال والتقنيات المرتبطة بالترحيل تحليلياً. وتُظهر نتائجنا اتجاهاً مثيراً للاهتمام: عندما يكون الاتصال بين المستخدم ووحدة الترحيل أقوى قليلاً من الاتصال المباشر، يكون من الأمثل استخدام الترميز المستقل فقط. وفي هذه الحالة، لا تحتاج وحدة الترحيل إلى استخدام كامل طاقتها. ومع ذلك، عند زيادة مكاسب الاتصال بين المستخدم ووحدة الترحيل، يجب على وحدة الترحيل دعم الترميز المستقل بترميز بلوكي من نوع ماركوف لتحقيق أكبر منطقة من معدلات الإرسال. إن أنماط حالات الاتصال هذه مهمة لتطبيق الترحيل ثنائي الاتجاه في شبكات الجيل الخامس، مثل الوضع المباشر بين الأجهزة (D2D) أو الإرسال المدعوم بالترحيل.
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We study classical and quantum hidden symmetries of a particle with electric charge $e$ in the background of a Dirac monopole of magnetic charge $g$ subjected to an additional central potential $V(r)=U(r) +(eg)^2/2mr^{2}$ with $U(r)=\tfrac{1}{2}m\omega^2r^2$, similar to that in the one-dimensional conformal mechanics model of de Alfaro, Fubini and Furlan (AFF). By means of a non-unitary conformal bridge transformation, we establish a relation of the quantum states and of all symmetries of the system with those of the system without harmonic trap, $U(r)=0$. Introducing spin degrees of freedom via a very special spin-orbit coupling, we construct the $\mathfrak{osp}(2,2)$ superconformal extension of the system with unbroken $\mathcal{N}=2$ Poincar\'e supersymmetry and show that two different superconformal extensions of the one-dimensional AFF model with unbroken and spontaneously broken supersymmetry have a common origin. We also show a universal relationship between the dynamics of a Euclidean particle in an arbitrary central potential $U(r)$ and the dynamics of a charged particle in a monopole background subjected to the potential $V(r)$.
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Studujeme klasické a kvantové skryté symetrie částice s elektrickým nábojem $e $ v poli Diracova monopolu s magnetickým nábojem $ g $, na kterou působí navíc centrální potenciál $ V(r)=U(r) +(eg)^2/2mr^{2} $, kde $ U(r)=\tfrac{1}{2}m\omega^2r^2 $, podobně jako v jednorozměrném modelu konformní mechaniky de Alfara, Fubiniho a Furlana (AFF). Pomocí neunitární konformní můstkové transformace stanovíme vztah mezi kvantovými stavy a všemi symetriemi systému a systémem bez harmonické pasti, kdy $ U(r)=0 $. Zavedením stupňů volnosti spinu prostřednictvím velmi speciální spin-orbitální vazby sestrojíme superkonformní rozšíření $ \mathfrak{osp}(2,2) $ systému s neporušenou $ \mathcal{N}=2 $ Poincar\'eho supersymetrií a ukážeme, že dvě různé superkonformní rozšíření jednorozměrného modelu AFF s neporušenou a spontánně porušenou supersymetrií mají společný původ. Dále ukážeme univerzální vztah mezi dynamikou eukleidovské částice v libovolném centrálním potenciálu $ U(r) $ a dynamikou nabité částice v poli monopolu, na kterou působí potenciál $ V(r) $.
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cs
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It was shown recently that the anomalous scaling of simultaneous correlation functions in turbulence is intimately related to the breaking of temporal scale invariance, which is equivalent to the appearance of infinitely many times scales in the time dependence of time-correlation functions. In this paper we derive a continued fraction representation of turbulent time correlation functions which is exact and in which the multiplicity of time scales is explicit. We demonstrate that this form yields precisely the same scaling laws for time derivatives and time integrals as the "multi-fractal" representation that was used before. Truncating the continued fraction representation yields the "best" estimates of time correlation functions if the given information is limited to the scaling exponents of the simultaneous correlation functions up to a certain, finite order. It is worth noting that the derivation of a continued fraction representation obtained here for an operator which is not Hermitian or anti-Hermitian may be of independent interest.
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Yakın zamanda, türbülans içindeki eşzamanlı korelasyon fonksiyonlarının anormal ölçeklenmesinin, zamansal ölçek değişmezliğinin kırılmasıyla yakından ilişkili olduğu gösterilmiştir ve bu durum, zaman korelasyon fonksiyonlarının zaman bağımlılığında sonsuz sayıda zaman ölçeğinin ortaya çıkmasına eşdeğerdir. Bu makalede, türbülanslı zaman korelasyon fonksiyonları için kesintisiz bir kesir gösterimi elde ediyoruz ve bu gösterim tam doğrudur ve zaman ölçeklerinin çokluğu burada açıkça ortadadır. Bu formun, daha önce kullanılan "çoklu-fraktal" gösterimle tam olarak aynı zaman türevleri ve zaman integralleri için ölçekleme yasalarını verdiğini gösteriyoruz. Sürekli kesir gösterimini kesmek, verilen bilgi eşzamanlı korelasyon fonksiyonlarının ölçekleme üslerine belli, sonlu bir mertebe kadar sınırlıysa, zaman korelasyon fonksiyonları için "en iyi" tahminleri verir. Burada Hermityen ya da anti-Hermityen olmayan bir operatör için elde edilen sürekli kesir gösteriminin çıkarımı bağımsız olarak da ilgi çekebilir.
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tr
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One way to recognise an object is to study how the echo has been shaped during the interaction with the target. Wideband sonar allows the study of the energy distribution for a large range of frequencies. The frequency distribution contains information about an object, including its inner structure. This information is a key for automatic recognition. The scattering by a target can be quantitatively described by its Form Function. The Form Function can be calculated based on the data of the initial pulse, reflected pulse and parameters of a medium where the pulse is propagating. In this work spherical objects are classified based on their filler material - water or air. We limit the study to spherical 2 layered targets immersed in water. The Form Function is used as a descriptor and fed into a Neural Network classifier, Multilayer Perceptron (MLP). The performance of the classifier is compared with Support Vector Machine (SVM) and the Form Function descriptor is examined in contrast to the Time and Frequency Representation of the echo.
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Salah satu cara mengenali suatu objek adalah dengan mempelajari bagaimana gema terbentuk selama interaksi dengan target. Sonar lebar pita memungkinkan studi distribusi energi pada rentang frekuensi yang luas. Distribusi frekuensi berisi informasi mengenai suatu objek, termasuk struktur bagian dalamnya. Informasi ini merupakan kunci untuk pengenalan otomatis. Hamburan oleh suatu target dapat dijelaskan secara kuantitatif melalui Fungsi Bentuk (Form Function). Fungsi Bentuk dapat dihitung berdasarkan data pulsa awal, pulsa terpantul, dan parameter medium tempat pulsa merambat. Dalam penelitian ini, objek berbentuk bola diklasifikasikan berdasarkan material isinya—air atau udara. Kami membatasi studi pada target bola dua lapisan yang terendam dalam air. Fungsi Bentuk digunakan sebagai deskriptor dan dimasukkan ke dalam klasifikasi Jaringan Syaraf Tiruan, Perseptron Berlapis (Multilayer Perceptron/MLP). Kinerja klasifier dibandingkan dengan Mesin Vektor Pendukung (Support Vector Machine/SVM), dan deskriptor Fungsi Bentuk dianalisis berbanding dengan Representasi Waktu dan Frekuensi dari gema.
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id
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Eugenio Regazzini was born on August 12, 1946 in Cremona (Italy), and took his degree in 1969 at the University "L. Bocconi" of Milano. He has held positions at the universities of Torino, Bologna and Milano, and at the University "L. Bocconi" as assistant professor and lecturer from 1974 to 1980, and then professor since 1980. He is currently professor in probability and mathematical statistics at the University of Pavia. In the periods 1989-2001 and 2006-2009 he was head of the Institute for Applications of Mathematics and Computer Science of the Italian National Research Council (C.N.R.) in Milano and head of the Department of Mathematics at the University of Pavia, respectively. For twelve years between 1989 and 2006, he served as a member of the Scientific Board of the Italian Mathematical Union (U.M.I.). In 2007, he was elected Fellow of the IMS and, in 2001, Fellow of the "Istituto Lombardo---Accademia di Scienze e Lettere." His research activity in probability and statistics has covered a wide spectrum of topics, including finitely additive probabilities, foundations of the Bayesian paradigm, exchangeability and partial exchangeability, distribution of functionals of random probability measures, stochastic integration, history of probability and statistics. Overall, he has been one of the most authoritative developers of de Finetti's legacy. In the last five years, he has extended his scientific interests to probabilistic methods in mathematical physics; in particular, he has studied the asymptotic behavior of the solutions of equations, which are of interest for the kinetic theory of gases. The present interview was taken in occasion of his 65th birthday.
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Эвдженио Регаццини 1946 жылдың 12 тамызында Кремона (Италия) қаласында дүниеге келген және 1969 жылы Миландың «Л. Боккони» университетінде білім алған. Ол 1974-1980 жылдары Турино, Болонья, Милан және «Л. Боккони» университеттерінде ассистент және оқытушы болып жұмыс істеген, содан кейін 1980 жылдан бастап профессор болды. Қазіргі уақытта ол Павия университетінде ықтималдық пен математикалық статистика профессоры. 1989-2001 және 2006-2009 жылдар аралығында ол Миландағы Италия Ұлттық зерттеу кеңесінің (C.N.R.) Математиканың және компьютерлік ғылымның қолданылуы институтының жетекшісі және сәйкесінше Павия университетінің математика кафедрасының меңгерушісі болды. 1989 жылдан 2006 жылға дейін он екі жыл бойы ол Италия математикалық одағының (U.M.I.) ғылыми кеңесінің мүшесі болды. 2007 жылы ол IMS-тің Fellow мүшесіне, ал 2001 жылы «Иституто Ломбардо – Ғылымдар мен әдебиет академиясының» Fellow мүшесіне сайланды. Ықтималдық пен статистика саласындағы зерттеу жұмыстары әлдеқайда кең тақырыптарды қамтыды, оған шектеулі қосылатын ықтималдықтар, Байес парадигмасының негіздері, ауыстырымдылық пен жартылай ауыстырымдылық, кездейсоқ ықтималдық өлшемдерінің функционалдарының таралуы, стохастикалық интеграция, ықтималдық пен статистиканың тарихы жатады. Жалпы алғанда, ол де Финетти мұрасының ең авторитетті дамытушыларының бірі болды. Соңғы бес жылда ол ғылыми қызығушылығын математикалық физикадағы ықтималдық әдістеріне дейін кеңейтті; атап айтқанда, газдардың кинетикалық теориясы үшін маңызы бар теңдеулердің шешімдерінің асимптоталық мінез-құлқын зерттеді. Бұл сұхбат оның 65 жасқа толуына арналып алынды.
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kk
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We report new HI observations of four z$\sim$0.05 star-forming galaxies undertaken during the commissioning phase of the Five-hundred-meter Aperture Spherical Radio Telescope (FAST). FAST is the largest single-dish telescope with a 500 meter aperture and a 19-Beam receiver. Exploiting the unprecedented sensitivity provided by FAST, we aim to study the atomic gas, via the HI 21cm emission line, in low-$z$ star-forming galaxies taken from the Valpara\'iso ALMA/APEX Line Emission Survey (VALES) project. Together with previous ALMA CO($J=1-0$) observations, the HI data provides crucial information to measure the gas mass and dynamics. As a pilot HI survey, we targeted four local star-forming galaxies at $z\sim0.05$. In particular, one of them has already been detected in HI by the Arecibo Legacy Fast ALFA survey (ALFALFA), allowing a careful comparison. We use an ON-OFF observing approach that allowed us to reach an rms of 0.7mJy/beam at a 1.7km/s velocity resolution within only 20 minutes ON-target integration time. We demonstrate the great capabilities of the FAST 19-beam receiver for pushing the detectability of the HI emission line of extra-galactic sources. The HI emission line detected by FAST shows good consistency with the previous ALFALFA results. Our observations are put in context with previous multi-wavelength data to reveal the physical properties of these low-$z$ galaxies. We find that the CO($J=1-0$) and HI emission line profiles are similar. The dynamical mass estimated from the HI data is an order of magnitude higher than the baryon mass and the dynamical mass derived from the CO observations, implying that the mass probed by dynamics of HI is dominated by the dark matter halo. In one case, a target shows an excess of CO($J=1-0$) in the line centre, which can be explained by an enhanced CO($J=1-0$) emission induced by a nuclear starburst showing high velocity dispersion.
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យើងខ្ញុំរាយការណ៍អំពីការសង្កេត HI ថ្មីៗចំពោះហ្គាឡាក់ស៊ីបង្កើតផ្កាយចំនួនបួន នៅ z$\sim$0.05 ដែលបានអនុវត្តក្នុងដំណាក់កាលដំបូងនៃការដំឡើងទូរទស្សន៍វិទ្យុប្រឡាយធំប្រាំម៉ែត្រ (FAST)។ FAST គឺជាទូរទស្សន៍វិទ្យុប្រឡាយតែមួយដ៏ធំបំផុតដែលមានប្រឡាយ 500 ម៉ែត្រ និងអង់តែន 19 កាំ។ ដោយប្រើប្រាស់ភាពរសើបដ៏អស្ចារ្យដែលផ្តល់ដោយ FAST យើងខ្ញុំបានស្វែងយកការសិក្សាអំពីឧស្ម័នអាតូមិកតាមរយៈបន្ទាត់បញ្ចេញពន្លឺ HI 21cm នៅក្នុងហ្គាឡាក់ស៊ីបង្កើតផ្កាយនៅតំបន់ z ទាប ដែលបានយកពីគម្រោងស្ទង់រកបន្ទាត់បញ្ចេញពន្លឺ Valparaíso ALMA/APEX (VALES)។ រួមជាមួយទិន្នន័យសង្កេតពី ALMA លើ CO($J=1-0$) ការសង្កេតពី HI ផ្តល់ព័ត៌មានសំខាន់ៗដើម្បីវាស់ម៉ាសនិងសកម្មភាពរបស់ឧស្ម័ន។ ជាការស្ទង់ដំបូងអំពី HI យើងខ្ញុំបានគោលដៅទៅកាន់ហ្គាឡាក់ស៊ីបង្កើតផ្កាយនៅតំបន់នោះចំនួនបួន នៅ z$\sim0.05$។ ជាពិសេស មួយក្នុងចំណោមវាត្រូវបានរកឃើញក្នុង HI រួចហើយដោយការស្ទង់ Arecibo Legacy Fast ALFA (ALFALFA) ដែលអនុញ្ញាតឱ្យយើងធ្វើការប្រៀបធៀបដោយប្រុងប្រយ័ត្ន។ យើងខ្ញុំបានប្រើវិធីសាស្ត្រសង្កេត ON-OFF ដែលអនុញ្ញាតឱ្យយើងឈានដល់ rms 0.7mJy/beam នៅកម្រិតភាពប្រែប្រួលល្បឿន 1.7km/s ក្នុងរយៈពេលតែ 20 នាទីនៃពេលវេលាសង្កេត។ យើងខ្ញុំបានបង្ហាញពីសមត្ថភាពដ៏អស្ចារ្យរបស់អង់តែន 19 កាំរបស់ FAST ក្នុងការពង្រីកសមត្ថភាពរកឃើញបន្ទាត់បញ្ចេញពន្លឺ HI នៃប្រភពខាងក្រៅហ្គាឡាក់ស៊ី។ បន្ទាត់បញ្ចេញពន្លឺ HI ដែលរកឃើញដោយ FAST បង្ហាញពីភាពស៊ីសង្វាក់គ្នាយ៉ាងល្អជាមួយលទ្ធផល ALFALFA មុន។ ការសង្កេតរបស់យើងត្រូវបានដាក់បញ្ចូលក្នុងបរិបទជាមួយទិន្នន័យពហុរលកមុនដើម្បីបង្ហាញពីលក្ខណៈរូបវិទ្យារបស់ហ្គាឡាក់ស៊ីទាំងនេះនៅតំបន់ z ទាប។ យើងរកឃើញថាប្រវត្តិបន្ទាត់បញ្ចេញពន្លឺ CO($J=1-0$) និង HI មានលក្ខណៈស្រដៀងគ្នា។ ម៉ាសដែលបានប៉ាន់ស្មានពីទិន្នន័យ HI គឺខ្ពស់ជាងម៉ាសប៉័រ្យូន និងម៉ាសដែលបានប៉ាន់ស្មានពីការសង្កេត CO មួយកម្រិត ដែលបង្ហាញថាម៉ាសដែលត្រូវបានវាស់ដោយសកម្មភាពរបស់ HI គឺគ្រប់គ្រងដោយគ្រាប់ម៉ាសងងឹត។ ក្នុងករណីមួយ គោលដៅបង្ហាញពីការលើសនៃ CO($J=1-0$) នៅចំណុចកណ្តាលបន្ទាត់ ដែលអាចពន្យល់បានដោយការបង្កើនការបញ្ចេញពន្លឺ CO($J=1-0$) ដែលបណ្តាលមកពីការផ្ទះៗផ្កាយនៅកណ្តាលដែលបង្ហាញពីភាពប្រែប្រួលល្បឿនខ្ពស់។
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km
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Ultra-high-energy cosmic rays (UHECRs) are the highest energy messengers in the universe, with energies up to $10^{20}$ eV. Studies of astrophysical particles (nuclei, electrons, neutrinos and photons) at their highest observed energies have implications for fundamental physics as well as astrophysics. The primary particles interact in the atmosphere (or in the Earth) and generate extensive air showers. Analysis of those showers enables one not only to estimate the energy, direction and most probable mass of the primary cosmic particles, but also to obtain information about the properties of their hadronic interactions at energies more than one order of magnitude above that accessible with the current highest energy human-made accelerator. The Pierre Auger Observatory, located in the province of Mendoza, Argentina, is the largest cosmic ray experiment ever built. The observatory was designed as a hybrid detector covering an area of 3000 km$^2$ and has been taking data for almost twenty years. In this paper, a selection of the latest results is presented: the cosmic ray energy spectrum, studies of hadronic physics, searches for a directional anisotropy and studies of mass composition (including the photon and neutrino searches). Finally, the current upgrade ("AugerPrime") of the observatory, which is mostly aimed at improving the sensitivity to the particle type and mass of ultra-high energy cosmic rays, is described.
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Ультравысокоэнергетические космические лучи (УВЭКЛ) являются самыми высокоэнергетическими посланниками во Вселенной с энергиями до $10^{20}$ эВ. Исследования астрофизических частиц (ядер, электронов, нейтрино и фотонов) при их самых высоких наблюдаемых энергиях имеют значение как для фундаментальной физики, так и для астрофизики. Первичные частицы взаимодействуют в атмосфере (или в теле Земли) и порождают широкие атмосферные ливни. Анализ этих ливней позволяет не только оценить энергию, направление и наиболее вероятную массу первичных космических частиц, но и получить информацию о свойствах их адронных взаимодействий при энергиях, превышающих более чем на порядок величину, доступную на современных ускорителях с наибольшими энергиями. Обсерватория Пьера Ожера, расположенная в провинции Мендоса, Аргентина, является крупнейшим экспериментом по изучению космических лучей, когда-либо построенным. Обсерватория создана как гибридный детектор, охватывающий площадь 3000 км$^2$, и собирает данные уже почти двадцать лет. В данной статье представлен отбор новейших результатов: спектр космических лучей по энергии, исследования адронной физики, поиски направленной анизотропии и исследования состава по массе (включая поиски фотонов и нейтрино). Наконец, описывается текущая модернизация обсерватории («AugerPrime»), основная цель которой — повысить чувствительность к типу и массе ультравысокоэнергетических космических лучей.
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ru
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Road user behavior prediction is one of the most critical components in trajectory planning for autonomous driving, especially in urban scenarios involving traffic signals. In this paper, a hierarchical framework is proposed to predict vehicle behaviors at a signalized intersection, using the traffic signal information of the intersection. The framework is composed of two phases: a discrete intention prediction phase and a continuous trajectory prediction phase. In the discrete intention prediction phase, a Bayesian network is adopted to predict the vehicle's high-level intention, after that, maximum entropy inverse reinforcement learning is utilized to learn the human driving model offline; during the online trajectory prediction phase, a driver characteristic is designed and updated to capture the different driving preferences between human drivers. We applied the proposed framework to one of the most challenging scenarios in autonomous driving: the yellow light running scenario. Numerical experiment results are presented in the later part of the paper which show the viability of the method. The accuracy of the Bayesian network for discrete intention prediction is 91.1%, and the prediction results are getting more and more accurate as the yellow time elapses. The average Euclidean distance error in continuous trajectory prediction is only 0.85 m in the yellow light running scenario.
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ການຄາດເດົາພຶດຕິກຳຂອງຜູ້ໃຊ້ຖະໜົນຖືວ່າເປັນໜຶ່ງໃນອົງປະກອບທີ່ສຳຄັນທີ່ສຸດໃນການວາງແຜນເສັ້ນທາງສຳລັບການຂັບຂີ່ອັດຕະໂນມັດ, ໂດຍສະເພາະໃນສະຖານະການເມືອງທີ່ກ່ຽວຂ້ອງກັບສັນຍານຈາລະຈອນ. ໃນບົດຄວາມນີ້, ພວກເຮົາຂໍເອົາລະບົບແບບຊັ້ນຊອງມາໃຊ້ເພື່ອຄາດເດົາພຶດຕິກຳຂອງລົດໃນສີ່ແຍກທີ່ມີສັນຍານ, ໂດຍໃຊ້ຂໍ້ມູນຂ່າວສານຂອງສັນຍານຈາລະຈອນຂອງສີ່ແຍກ. ລະບົບດັ່ງກ່າວປະກອບດ້ວຍສອງຂັ້ນຕອນ: ຂັ້ນຕອນການຄາດເດົາເຈດຕະນາແບບແຍກຕ່າງຫາກ ແລະ ຂັ້ນຕອນການຄາດເດົາເສັ້ນທາງແບບຕໍ່ເນື່ອງ. ໃນຂັ້ນຕອນການຄາດເດົາເຈດຕະນາແບບແຍກຕ່າງຫາກ, ພວກເຮົານຳໃຊ້ເຄືອຂ່າຍເບເຍ (Bayesian network) ເພື່ອຄາດເດົາເຈດຕະນາຂອງລົດໃນລະດັບສູງ, ຕໍ່ມາຈະນຳໃຊ້ການຮຽນຮູ້ການເສີມອັນດັບສູງສຸດ (maximum entropy inverse reinforcement learning) ເພື່ອຮຽນຮູ້ຮູບແບບການຂັບຂີ່ຂອງມະນຸດຢ່າງອິດສະລະ; ໃນຂະນະທີ່ຂັ້ນຕອນການຄາດເດົາເສັ້ນທາງແບບຕໍ່ເນື່ອງ, ພວກເຮົາອອກແບບ ແລະ ອັບເດດລັກສະນະຂອງຜູ້ຂັບຂີ່ເພື່ອຈັບເອົາຄວາມຕ້ອງການໃນການຂັບຂີ່ທີ່ແຕກຕ່າງກັນລະຫວ່າງຜູ້ຂັບຂີ່. ພວກເຮົາໄດ້ນຳໃຊ້ລະບົບທີ່ສະເໜີນີ້ໃນໜຶ່ງໃນສະຖານະການທີ່ທ້າທາຍທີ່ສຸດໃນການຂັບຂີ່ອັດຕະໂນມັດ: ສະຖານະການຂັບຂີ່ໃຕ້ແສງເຫຼືອງ. ຜົນໄດ້ຮັບຈາກການທົດລອງເຊິ່ງສະແດງໃຫ້ເຫັນເຖິງຄວາມເປັນໄປໄດ້ຂອງວິທີການດັ່ງກ່າວຈະຖືກນຳມາສະເໜີໃນສ່ວນທ້າຍຂອງບົດຄວາມ. ຄວາມຖືກຕ້ອງຂອງເຄືອຂ່າຍເບເຍໃນການຄາດເດົາເຈດຕະນາແບບແຍກຕ່າງຫາກແມ່ນ 91.1%, ແລະ ຜົນການຄາດເດົາກໍຈະຍິ່ງມີຄວາມຖືກຕ້ອງຫຼາຍຂຶ້ນເມື່ອເວລາແສງເຫຼືອງຜ່ານໄປ. ຂໍ້ຜິດພາດໃນໄລຍະທາງອີວຄລິດ (Euclidean distance) ເສັ້ນທາງແບບຕໍ່ເນື່ອງສະເລ່ຍແມ່ນພຽງແຕ່ 0.85 ແມັດໃນສະຖານະການຂັບຂີ່ໃຕ້ແສງເຫຼືອງ.
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lo
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Massive rotating single stars with an initial metal composition appropriate for the dwarf galaxy I Zw 18 ([Fe/H]=$-$1.7) are modelled during hydrogen burning for initial masses of 9-300 M$_{\odot}$ and rotational velocities of 0-900 km s$^{-1}$. Internal mixing processes in these models were calibrated based on an observed sample of OB-type stars in the Magellanic Clouds. Even moderately fast rotators, which may be abundant at this metallicity, are found to undergo efficient mixing induced by rotation resulting in quasi chemically-homogeneous evolution. These homogeneously-evolving models reach effective temperatures of up to 90 kK during core hydrogen burning. This, together with their moderate mass-loss rates, make them Transparent Wind Ultraviolet INtense stars (TWUIN star), and their expected numbers might explain the observed HeII ionizing photon flux in I Zw 18 and other low-metallicity HeII galaxies. Our slowly rotating stars above $\sim$80 M$_{\odot}$ evolve into late B- to M-type supergiants during core hydrogen burning, with visual magnitudes up to 19$^{\mathrm{m}}$ at the distance of I Zw 18. Both types of stars, TWUIN stars and luminous late-type supergiants, are only predicted at low metallicity. Massive star evolution at low metallicity is shown to differ qualitatively from that in metal-rich environments. Our grid can be used to interpret observations of local star-forming dwarf galaxies and high-redshift galaxies, as well as the metal-poor components of our Milky Way and its globular clusters.
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Bintang tunggal berputar besar dengan komposisi logam awal yang sesuai untuk galaksi kerdil I Zw 18 ([Fe/H] = $-$1.7) dimodelkan semasa pembakaran hidrogen bagi jisim awal 9–300 M$_{\odot}$ dan halaju putaran 0–900 km s$^{-1}$. Proses pencampuran dalaman dalam model-model ini dikalibrasi berdasarkan sampel bintang jenis OB yang dicerap di Awan Magellan. Didapati bahawa pemutar yang agak pantas, yang mungkin banyak wujud pada metalisiti ini, mengalami pencampuran cekap yang diaruhkan oleh putaran, mengakibatkan evolusi yang hampir homogen secara kimia. Model-model yang berevolusi secara homogen ini mencapai suhu berkesan sehingga 90 kK semasa pembakaran hidrogen teras. Ini, bersama-sama dengan kadar kehilangan jisim sederhana mereka, menjadikan mereka bintang Angin Lutsinar Ultralegapan INTENS (bintang TWUIN), dan bilangan jangkaan mereka mungkin dapat menjelaskan fluks foton pengionan HeII yang dicerap dalam I Zw 18 dan galaksi HeII lain yang rendah metalisitinya. Bintang-bintang yang berputar perlahan milik kita di atas $\sim$80 M$_{\odot}$ berkembang menjadi raksasa super jenis B akhir hingga M semasa pembakaran hidrogen teras, dengan magnitud visual sehingga 19$^{\mathrm{m}}$ pada jarak I Zw 18. Kedua-dua jenis bintang ini, bintang TWUIN dan raksasa super jenis akhir bersinar, hanya diramalkan wujud pada metalisiti rendah. Evolusi bintang besar pada metalisiti rendah ditunjukkan berbeza secara kualitatif daripada evolusi dalam persekitaran yang kaya logam. Grid kita boleh digunakan untuk mentafsir pencerapan galaksi kerdil pembentuk bintang setempat dan galaksi beranjakan-merah tinggi, serta komponen-komponen yang kurang logam dalam Bima Sakti kita dan gugusan globularnya.
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ms
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Ultra-high-energy cosmic rays (UHECRs) are the highest energy messengers in the universe, with energies up to $10^{20}$ eV. Studies of astrophysical particles (nuclei, electrons, neutrinos and photons) at their highest observed energies have implications for fundamental physics as well as astrophysics. The primary particles interact in the atmosphere (or in the Earth) and generate extensive air showers. Analysis of those showers enables one not only to estimate the energy, direction and most probable mass of the primary cosmic particles, but also to obtain information about the properties of their hadronic interactions at energies more than one order of magnitude above that accessible with the current highest energy human-made accelerator. The Pierre Auger Observatory, located in the province of Mendoza, Argentina, is the largest cosmic ray experiment ever built. The observatory was designed as a hybrid detector covering an area of 3000 km$^2$ and has been taking data for almost twenty years. In this paper, a selection of the latest results is presented: the cosmic ray energy spectrum, studies of hadronic physics, searches for a directional anisotropy and studies of mass composition (including the photon and neutrino searches). Finally, the current upgrade ("AugerPrime") of the observatory, which is mostly aimed at improving the sensitivity to the particle type and mass of ultra-high energy cosmic rays, is described.
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Sinar kosmik tenaga ultra-tinggi (UHECRs) merupakan pembawa tenaga tertinggi di alam semesta, dengan tenaga sehingga $10^{20}$ eV. Kajian zarah astofizik (nukleus, elektron, neutrino dan foton) pada tenaga tertinggi yang diperhatikan mempunyai implikasi terhadap fizik asas serta astrofizik. Zarah primer ini berinteraksi dalam atmosfera (atau di dalam Bumi) dan menghasilkan hujan udara meluas. Analisis hujan-hujan tersebut membolehkan kita bukan sahaja menganggar tenaga, arah dan jisim yang paling berkemungkinan bagi zarah kosmik primer, tetapi juga memperoleh maklumat mengenai sifat-sifat interaksi hadronik mereka pada tenaga yang melebihi lebih daripada satu darab magnitud berbanding tenaga yang boleh dicapai oleh pemecut buatan manusia dengan tenaga tertinggi semasa ini. Pemerhatian Pierre Auger, yang terletak di wilayah Mendoza, Argentina, merupakan eksperimen sinar kosmik terbesar yang pernah dibina. Pemerhatian ini direka sebagai pengesan hibrid yang merangkumi kawasan seluas 3000 km$^2$ dan telah mengumpul data selama hampir dua puluh tahun. Dalam kertas ini, dipaparkan satu pemilihan keputusan terkini: spektrum tenaga sinar kosmik, kajian fizik hadronik, pencarian anisotropi mengikut arah dan kajian komposisi jisim (termasuk pencarian foton dan neutrino). Akhir sekali, dilaporkan tentang pengemaskinian semasa ("AugerPrime") pemerhatian ini, yang terutamanya bertujuan meningkatkan kepekaan terhadap jenis zarah dan jisim sinar kosmik tenaga ultra-tinggi.
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ms
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The formulation of the tensor virial equations is generalized to unrelaxed configurations, where virial equilibrium does not coincide with dynamical (or hydrostatic) equilibrium. Further investigation is devoted to special classes of homeoidally striated ellipsoids, defined as homeoidally striated, Jacobi ellipsoids. In particular, virial equilibrium configurations with constant anisotropy parameters are studied with more detail, including both flattened and elongated, triaxial configurations, and the determination of the related bifurcation points. The explicit expression of different rotation parameters is also determined. An application is made to dark matter haloes hosting giant, galaxies, with regard to assigned initial and final configuration, following and generalizing to many respects a procedure conceived by Thuan & Gott (1975). The dependence of the limiting axis ratios, below which no configuration is allowed for the sequence under consideration, on the change in mass, total energy, and angular momentum, during the evolution, is illustrated in some representative situations. The dependence of axis ratios and rotation parameters on an additional parameter, related to the initial conditions of the density perturbation, is analysed in connection with a few special cases. Within the range of Peebles (1969) rotation parameter, inferred from high-resolution numerical simulations, the shape of dark matter haloes is mainly decided by the amount of anisotropy in residual velocity distribution. On the other hand, the contribution of rotation has only a minor effect on the meridional plane, and no effect on the equatorial plane, as bifurcation points occur for larger values of Peebles (1969) rotation parameter. To this respect, dark matter haloes are found to resemble giant elliptical galaxies.
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تنسور وائریل مساوات کی تشکیل کو غیر متوازن ترتیبات تک وسیع کیا گیا ہے، جہاں وائریل توازن، دینامکی (یا ہائیڈرو اسٹیٹک) توازن کے ہم آہنگ نہیں ہوتا۔ مزید تحقیق ہومیوڈلی سٹریٹیفائیڈ الپسوائیڈز کی خاص اقسام کے لیے وقف ہے، جنہیں ہومیوڈلی سٹریٹیفائیڈ، جیکوبی الپسوائیڈز کے طور پر تعریف کیا گیا ہے۔ خاص طور پر، مسلسل اینیسوٹروپی پیرامیٹرز کے ساتھ وائریل توازن کی ترتیبات کا مطالعہ مزید تفصیل کے ساتھ کیا گیا ہے، جس میں چپٹی اور لمبی دونوں قسم کی تھری ایکسیل ترتیبات شامل ہیں، اور متعلقہ بائی فرکیشن پوائنٹس کا تعین بھی شامل ہے۔ مختلف گردش کے پیرامیٹرز کی صریح اظہار بھی متعین کی گئی ہے۔ بڑے درجے کی کہکشانوں کو اپنے اندر رکھنے والے ڈارک میٹر ہیلو کے لیے ایک درخواست پیش کی گئی ہے، مخصوص ابتدائی اور حتمی ترتیب کے حوالے سے، جو تھوان اور گاٹ (1975) کے تصور کردہ طریقہ کار کی پیروی کرتی ہے اور اس کی کئی پہلوؤں میں توسیع بھی کرتی ہے۔ ترتیبات کے مخصوص سلسلے کے لیے جن محور تناسب کی حدود کا تعین کیا گیا ہے، جس کے نیچے کوئی بھی ترتیب جائز نہیں ہوتی، اور جو مجموعی مادہ، کل توانائی، اور زاویائی حرکت میں تبدیلی کے ساتھ تبدیلی کے دوران منسلک ہوتی ہیں، کو کچھ نمائندہ صورتحال میں واضح کیا گیا ہے۔ محور تناسب اور گردش کے پیرامیٹرز کی ایک اضافی پیرامیٹر پر، جو کثافت میں ابتدائی خلل کی ابتدائی شرائط سے منسلک ہے، پر منحصر تجزیہ کچھ خاص صورتوں کے تناظر میں کیا گیا ہے۔ پیبلز (1969) کے گردش کے پیرامیٹر کی حدود کے اندر، جو ہائی ریزولوشن عددی محاکات سے استنباط کی گئی ہے، ڈارک میٹر ہیلو کی شکل خاص طور پر باقی ماندہ رفتار تقسیم میں اینیسوٹروپی کی مقدار پر منحصر ہوتی ہے۔ دوسری طرف، گردش کا مرکزی سطح پر صرف معمولی اثر پڑتا ہے، اور استوائی سطح پر کوئی اثر نہیں پڑتا، کیونکہ بائی فرکیشن پوائنٹس پیبلز (1969) گردش کے پیرامیٹر کی بڑی قیمتوں پر پیدا ہوتے ہیں۔ اس حوالے سے، ڈارک میٹر ہیلو بڑی بیضوی کہکشانوں کی مانند پائے گئے ہیں۔
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ur
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Context. The dynamical evolution of near-parabolic comets strongly depends on the starting values of the orbital elements derived from the positional observations. In addition, when drawing conclusions about the origin of these objects, it is crucial to control the uncertainties of orbital elements at each stage of the dynamical evolution. Aims. I apply a completely homogeneous approach to determine the cometary orbits and their uncertainties. The resulting catalogue is suitable for the investigation of the origin and future of near-parabolic comets. Methods. First, osculating orbits were determined on the basis of positional data. Second, the dynamical calculations were performed backwards and forwards up to 250 au from the Sun to derive original and future barycentric orbits for each comet. In the present investigation of dynamical evolution, the numerical calculations for a given object start from the swarm of virtual comets constructed using the previously determined osculating (nominal) orbit. In this way, the uncertainties of orbital elements were derived at the end of numerical calculations. Results. Homogeneous sets of orbital elements for osculating, original and future orbits are given. The catalogue of 119 cometary orbits constitutes about 70 per cent of all the first class so-called Oort spike comets discovered during the period of 1801-2010 and about 90 per cent of those discovered in 1951-2010, for which observations were completed at the end of 2013. Non-gravitational (NG) orbits are derived for 45 comets, including asymmetric NG~solution for six of them. Additionally, the new method for cometary orbit-quality assessment is applied for all these objects.
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প্রেক্ষাপট। অবস্থানগত পর্যবেক্ষণের ভিত্তিতে প্রাপ্ত কক্ষপথের আদি উপাদানগুলির আদি মানগুলির উপর প্রায়-পরাবৃত্তাকার ধূমকেতুগুলির গতিময় বিবর্তন খুব নির্ভরশীল। এছাড়াও, এই বস্তুগুলির উৎপত্তি সম্পর্কে সিদ্ধান্ত নেওয়ার সময়, গতিময় বিবর্তনের প্রতিটি পর্যায়ে কক্ষপথের উপাদানগুলির অনিশ্চয়তা নিয়ন্ত্রণ করা অত্যন্ত গুরুত্বপূর্ণ। উদ্দেশ্য। আমি ধূমকেতুর কক্ষপথ এবং তাদের অনিশ্চয়তা নির্ধারণের জন্য একটি সম্পূর্ণ সমসত পদ্ধতি প্রয়োগ করি। ফলাফলে প্রাপ্ত তালিকাটি প্রায়-পরাবৃত্তাকার ধূমকেতুগুলির উৎপত্তি এবং ভবিষ্যৎ তদন্তের জন্য উপযুক্ত। পদ্ধতি। প্রথমে, অবস্থানগত তথ্যের ভিত্তিতে অস্কুলেটিং কক্ষপথগুলি নির্ধারণ করা হয়েছিল। দ্বিতীয়ত, প্রতিটি ধূমকেতুর জন্য মূল এবং ভবিষ্যতের ব্যারিসেন্ট্রিক কক্ষপথ প্রাপ্ত করার জন্য সূর্য থেকে 250 এ.ইউ. পর্যন্ত পিছন এবং সামনের দিকে গতিময় গণনা করা হয়েছিল। গতিময় বিবর্তনের বর্তমান তদন্তে, পূর্বে নির্ধারিত অস্কুলেটিং (নমিনাল) কক্ষপথ ব্যবহার করে গঠিত ভার্চুয়াল ধূমকেতুগুলির ঝাঁক থেকে একটি নির্দিষ্ট বস্তুর জন্য সংখ্যাগত গণনাগুলি শুরু করা হয়। এই পদ্ধতিতে, সংখ্যাগত গণনার শেষে কক্ষপথের উপাদানগুলির অনিশ্চয়তা প্রাপ্ত হয়। ফলাফল। অস্কুলেটিং, মূল এবং ভবিষ্যতের কক্ষপথের জন্য কক্ষপথের উপাদানগুলির সমসত সেটগুলি দেওয়া হয়েছে। 119টি ধূমকেতুর কক্ষপথের তালিকাটি 1801-2010 সময়কালে আবিষ্কৃত সমস্ত প্রথম শ্রেণীর তথাকথিত ওর্ট স্পাইক ধূমকেতুগুলির প্রায় 70 শতাংশ এবং 1951-2010 সময়ে আবিষ্কৃত সেগুলির প্রায় 90 শতাংশ গঠন করে, যাদের পর্যবেক্ষণ 2013 এর শেষ পর্যন্ত সম্পন্ন হয়েছিল। 45টি ধূমকেতুর জন্য অ-মহাকর্ষীয় (এনজি) কক্ষপথগুলি প্রাপ্ত হয়েছে, যার মধ্যে ছয়টির জন্য অসম এনজি সমাধান অন্তর্ভুক্ত রয়েছে। এছাড়াও, ধূমকেতুর কক্ষপথের গুণমান মূল্যায়নের জন্য একটি নতুন পদ্ধতি এই সমস্ত বস্তুগুলির জন্য প্রয়োগ করা হয়।
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bn
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Let kappa be an uncountable regular cardinal. Call an equivalence relation on functions from kappa into 2 Sigma_1^1-definable over H(kappa) if there is a first order sentence F and a parameter R subseteq H(kappa) such that functions f,g:kappa --> 2 are equivalent iff for some h:kappa --> 2, the structure (H(kappa),in,R,f,g,h) satisfies F, where in, R, f, g, and h are interpretations of the symbols appearing in F. All the values mu, 1 leq mu leq kappa^+ or mu=2^kappa, are possible numbers of equivalence classes for such a Sigma_1^1-equivalence relation. Additionally, the possibilities are closed under unions of <=kappa-many cardinals and products of <kappa-many cardinals. We prove that, consistent wise, these are the only restrictions under the singular cardinal hypothesis. The result is that the possible numbers of equivalence classes of Sigma_1^1-equivalence relations might consistent wise be exactly those cardinals which are in a prearranged set, provided that the singular cardinal hypothesis holds and that some necessary conditions are fulfilled.
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设κ为一个不可数的正则基数。称一个从κ到2的函数上的等价关系是H(κ)上的Σ₁¹-可定义的，如果存在一个一阶句子F和一个参数R ⊆ H(κ)，使得函数f, g: κ → 2等价当且仅当存在某个h: κ → 2，使得结构(H(κ), ∈, R, f, g, h)满足F，其中∈、R、f、g和h分别是F中出现符号的解释。所有取值μ，其中1 ≤ μ ≤ κ⁺ 或 μ = 2^κ，都是此类Σ₁¹-等价关系的等价类个数的可能取值。此外，这些可能的取值在不超过κ个基数的并和少于κ个基数的乘积下是封闭的。我们证明，在一致性意义上，若奇数基数假设成立，则这些是唯一的限制条件。结果是，在奇数基数假设成立且某些必要条件满足的前提下，Σ₁¹-等价关系的等价类个数可能取到的基数恰好是某个预先设定集合中的那些基数，这在一致性意义上是可能的。
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zh
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We employ the Schwinger boson mean-field approach to study the effects of arbitrary frustrated bonds and plaquettes (formed from four frustrated bonds) in two-dimensional ferro- and antiferromagnets on the spin-wave spectrum and the correlation length at finite temperatures. We distinguish between strongly frustrated bonds (plaquettes), when the frustrated coupling $J^\prime$ exceeds the spin canting threshold $J_c$, and weakly frustrated bonds (plaquettes), with $J^\prime <J_c, (J_c-J^\prime)/J_c\sim 1$. It is shown that in antiferromagnets the amplitude of spin-wave scattering on strongly frustrated bonds or plaquettes grows with the decrease of the temperature. A small amount of such defects reduces significantly the spin-wave stiffness and the correlation length at low temperatures. As a result, the quasi-2D N\'eel temperature is sharply suppressed. Quantum fluctuations are also considered and their effect on the spin-wave spectrum is shown to be of the order of $(2S)^{-2}\ln^{-1}2S$ in the large spin limit. For weakly frustrated (nonfrustrated) defect bonds (plaquettes) the spin-wave stiffness renormalization is of the order of the dopant concentration and does not depend on the temperature. The results account for the observed properties of doped quasi-2D $La_2CuO_{4+x}$.
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Utilizamos a abordagem de campo médio de bósons de Schwinger para estudar os efeitos de ligações frustradas arbitrárias e plaquetas (formadas por quatro ligações frustradas) em ferro- e antiferromagnetos bidimensionais sobre o espectro de ondas de spin e o comprimento de correlação em temperaturas finitas. Distinguimos entre ligações (plaquetas) fortemente frustradas, quando o acoplamento frustrado $J^\prime$ excede o limiar de inclinação do spin $J_c$, e ligações (plaquetas) fracamente frustradas, com $J^\prime < J_c$, $(J_c - J^\prime)/J_c \sim 1$. Mostra-se que em antiferromagnetos a amplitude do espalhamento de ondas de spin em ligações ou plaquetas fortemente frustradas cresce com a diminuição da temperatura. Uma pequena quantidade desses defeitos reduz significativamente a rigidez da onda de spin e o comprimento de correlação em baixas temperaturas. Como resultado, a temperatura de Néel quase-2D é fortemente suprimida. As flutuações quânticas também são consideradas, e seu efeito sobre o espectro de ondas de spin mostra-se da ordem de $(2S)^{-2}\ln^{-1}2S$ no limite de spin grande. Para ligações (plaquetas) defeituosas fracamente frustradas (não frustradas), a renormalização da rigidez da onda de spin é da ordem da concentração do dopante e não depende da temperatura. Os resultados explicam as propriedades observadas em $La_2CuO_{4+x}$ quase-2D dopado.
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pt
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Multicomponent bilayer structures arise as the ubiquitous plasma membrane in cellular biology and as blends of amphiphilic copolymers used in electrolyte membranes, drug delivery, and emulsion stabilization within the context of synthetic chemistry. We develop the multicomponent functionalized Cahn-Hilliard (mFCH) free energy as a model which allows competition between bilayers with distinct composition and between bilayers and higher codimensional structures, such as co-dimension two filaments and co-dimension three micelles. We investigate the stability and slow geometric evolution of multicomponent bilayer interfaces within the context of gradient flows of the mFCH, addressing the impact of aspect ratio of the lipid/copolymer unit on the intrinsic curvature and the codimensional bifurcation. In particular we derive a Canham-Helfrich sharp interface energy whose intrinsic curvature arises through a Melnikov parameter associated to lipid aspect ratio. We construct asymmetric homoclinic bilayer profiles via a billiard limit potential and show that the dominant co-dimensional bifurcation mechanism is via the layer-by-layer pearling observed experimentally.
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다성분 이중층 구조는 세포 생물학에서 보편적인 세포막으로 나타나며, 합성 화학의 맥락에서 전해질막, 약물 전달 및 유화 안정화에 사용되는 양친매성 블록공중합체의 혼합물로도 나타난다. 본 연구에서는 서로 다른 조성을 지닌 이중층들 사이 또는 이중층과 2차원 잔여(codimension two) 실형 구조(filaments) 및 3차원 잔여(codimension three) 미셀과 같은 더 높은 잔여 차원 구조들 사이의 경쟁을 설명할 수 있도록 해주는 다성분 기능화 카한-힐리어드(mFCH) 자유에너지 모델을 개발한다. 우리는 mFCH의 기울기 흐름 맥락에서 다성분 이중층 계면의 안정성과 느린 기하학적 진화를 조사하며, 지질/공중합체 단위의 종횡비(aspect ratio)가 고유 곡률 및 잔여 차원 분기(codimensional bifurcation)에 미치는 영향을 분석한다. 특히, 지질의 종횡비에 관련된 멜니코프 파라미터를 통해 고유 곡률이 유도되는 캔햄-헬프리크(Canham-Helfrich) 날카로운 계면 에너지를 도출한다. 우리는 빌리어드 극한 퍼텐셜을 통해 비대칭 동질성 이중층 프로파일을 구성하고, 실험적으로 관찰된 층별 배 모양 펄링(layer-by-layer pearling)을 통해 지배적인 잔여 차원 분기 메커니즘이 작용함을 보인다.
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ko
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We propose an online visual tracking algorithm by learning discriminative saliency map using Convolutional Neural Network (CNN). Given a CNN pre-trained on a large-scale image repository in offline, our algorithm takes outputs from hidden layers of the network as feature descriptors since they show excellent representation performance in various general visual recognition problems. The features are used to learn discriminative target appearance models using an online Support Vector Machine (SVM). In addition, we construct target-specific saliency map by backpropagating CNN features with guidance of the SVM, and obtain the final tracking result in each frame based on the appearance model generatively constructed with the saliency map. Since the saliency map visualizes spatial configuration of target effectively, it improves target localization accuracy and enable us to achieve pixel-level target segmentation. We verify the effectiveness of our tracking algorithm through extensive experiment on a challenging benchmark, where our method illustrates outstanding performance compared to the state-of-the-art tracking algorithms.
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ကွန်ဗျူးလူးရှင်နယ် နျူရယ်နက်ဝပ် (CNN) ကို အသုံးပြု၍ ကွဲပြားခြားနားသော သတိထားမိမှု မြေပုံကို သင်ကြားခြင်းဖြင့် အွန်လိုင်း ပုံရိပ် ခြေရာခံမှု အယ်လ်ဂိုရီသမ်တစ်ခုကို ကျွန်ုပ်တို့ အဆိုပြုပါသည်။ အော့ဖ်လိုင်းတွင် ပုံရိပ် သိုလှောင်မှု အကြီးစားတစ်ခုပေါ်တွင် ကြိုတင်သင်ကြားထားသော CNN တစ်ခုအား ပေးထားပါက၊ ကျွန်ုပ်တို့၏ အယ်လ်ဂိုရီသမ်သည် ကွန်ဗျူးလူးရှင်နယ် နက်ဝပ်ဝှက်ခ်တွင် မှောင်သော အလွှာများမှ ရလဒ်များကို အင်္ဂါရပ် ဖော်ပြချက်များအဖြစ် ယူပါသည်။ အကြောင်းမှာ ၎င်းတို့သည် ယေဘုယျ ပုံရိပ် အသိအမှတ်ပြုမှု ပြဿနာများစွာတွင် ကောင်းမွန်သော ကိုယ်စားပြုမှု စွမ်းဆောင်ရည်ကို ပြသသောကြောင့် ဖြစ်ပါသည်။ အင်္ဂါရပ်များကို အွန်လိုင်း Support Vector Machine (SVM) ကို အသုံးပြု၍ ကွဲပြားခြားနားသော ပစ်မှတ်၏ ပေါ်လွင်မှု မော်ဒယ်များကို သင်ကြားရန် အသုံးပြုပါသည်။ ထပ်မံ၍ SVM ၏ လမ်းညွှန်မှုဖြင့် CNN အင်္ဂါရပ်များကို ပြန်လည် ပို့ဆောင်ခြင်းဖြင့် ပစ်မှတ်အထူးသီးသန့် သတိထားမိမှု မြေပုံကို တည်ဆောက်ပြီး၊ သတိထားမိမှု မြေပုံဖြင့် ဖန်တီးထားသော ပေါ်လွင်မှု မော်ဒယ်ကို အခြေခံ၍ တစ်ဖရိမ်ချင်းစီတွင် နောက်ဆုံး ခြေရာခံမှု ရလဒ်ကို ရယူပါသည်။ သတိထားမိမှု မြေပုံသည် ပစ်မှတ်၏ နေရာချထားမှု ဖွဲ့စည်းပုံကို ထိရောက်စွာ ပြသသောကြောင့် ပစ်မှတ်၏ တည်နေရာ တိကျမှုကို မြှင့်တင်ပေးပြီး ပစ်မှတ်၏ ပစ်ကယ် အဆင့် ကွဲပြားမှုကို ရယူနိုင်စေပါသည်။ ကျွန်ုပ်တို့၏ နည်းလမ်းသည် ခေတ်မီ ခြေရာခံမှု အယ်လ်ဂိုရီသမ်များနှင့် နှိုင်းယှဉ်ပါက ထင်ရှားသော စွမ်းဆောင်ရည်ကို ပြသသည့် စိန်ခေါ်မှုများပါဝင်သော စံပြစမ်းသပ်မှုတစ်ခုတွင် ကျွန်ုပ်တို့၏ ခြေရာခံမှု အယ်လ်ဂိုရီသမ်၏ ထိရောက်မှုကို စမ်းသပ် အတည်ပြုပါသည်။
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my
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In this thesis we consider the polarized deep inelastic scattering in the region of low values of Bjorken variable, $x$. We formulate the evolution equations for the unintegrated parton distributions which include a complete resummation of the double logarithmic contributions, $\ln^2(1/x)$. Afterwards, these equations are completed with the standard LO and NLO DGLAP evolution terms, in order to obtain the proper behaviour of the parton distributions at moderate and large values of $x$. The equations obtained are applied to the following observables and processes: (i) to the nucleon structure function, $g_1$, in the polarized deep inelastic scattering, (ii) to the structure function of the polarized photon, $g_1^{\gamma}$, in the scattering of a lepton on a polarized photon, and (iii) to the differential structure function, $x_J d^2g_1/dx_J dk_J^2$, in the polarized deep inelastic scattering accompanied by a forward jet. Case (iii) is proposed to be a test process for the presence and the magnitude of the $\ln^2(1/x)$ contributions. For each process the consequences of including the logarithmic corrections are studied in a detail. After integrating out the structure function, $g_1$, the moments of the nucleon structure function are obtained. The contribution of the region of low $x$ to these moments is estimated, and then discussed in the context of the spin sum rules. Finally, some predictions for the observables, the asymmetry and the cross sections, in the processes (i)-(iii) are given. They are important to planned experiments with the polarized HERA and linear colliders, which will probe the region of low values of Bjorken $x$.
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នៅក្នុងប្រធានបទនេះ យើងពិចារណាលើការរាវរកជម្រៅដែលមានការបំបែកគោលកម្មវិធីនៅក្នុងតំបន់ដែលតម្លៃអថេរ Bjorken មានតម្លៃទាប $x$។ យើងបង្កើតសមីការវិវត្តន៍សម្រាប់ការចែកចាយផ្នែកដែលមិនបានបញ្ចូលដែលរួមបញ្ចូលការបូកសរុបពេញលេញនៃចំណែកដែលមានកត្តាកំណត់ $\ln^2(1/x)$។ បន្ទាប់មក សមីការទាំងនេះត្រូវបានបំពេញដោយចំណែកវិវត្តន៍ DGLAP ស្តង់ដារ LO និង NLO ដើម្បីទទួលបានឥរិយាបថត្រឹមត្រូវនៃការចែកចាយផ្នែកនៅតម្លៃមធ្យមនិងធំនៃ $x$។ សមីការដែលទទួលបានត្រូវបានអនុវត្តចំពោះតម្លៃដែលអាចសង្កេតបាននិងដំណើរការដូចខាងក្រោម៖ (i) ចំពោះមុខងាររចនាសម្ព័ន្ធនូគ្លេអុង $g_1$ នៅក្នុងការរាវរកជម្រៅដែលមានការបំបែកគោលកម្មវិធី (ii) ចំពោះមុខងាររចនាសម្ព័ន្ធនៃផូតុងដែលមានគោលកម្មវិធី $g_1^{\gamma}$ នៅក្នុងការរាវរកអេឡិចត្រុងលើផូតុងដែលមានគោលកម្មវិធី និង (iii) ចំពោះមុខងាររចនាសម្ព័ន្ធឌីផែរ៉ង់ស្យែល $x_J d^2g_1/dx_J dk_J^2$ នៅក្នុងការរាវរកជម្រៅដែលមានការបំបែកគោលកម្មវិធីដែលបន្ថែមដោយកាំមុខ។ ករណី (iii) ត្រូវបានស្នើឱ្យជាដំណើរការសាកល្បងសម្រាប់ភាពមាននិងទំហំនៃចំណែក $\ln^2(1/x)$។ សម្រាប់ដំណើរការនីមួយៗ ការសិក្សាលម្អិតអំពីផលប៉ះពាល់នៃការបញ្ចូលកំហាប់កត្តាកំណត់ត្រូវបានធ្វើឡើង។ បន្ទាប់ពីធ្វើប្រមាណវិធីបញ្ចូលមុខងាររចនាសម្ព័ន្ធ $g_1$ គេទទួលបានម៉ូម៉ង់នៃមុខងាររចនាសម្ព័ន្ធនូគ្លេអុង។ ចំណែកនៃតំបន់ $x$ ទាបចំពោះម៉ូម៉ង់ទាំងនេះត្រូវបានប៉ាន់ស្មាន ហើយបន្ទាប់មកពិភាក្សាក្នុងបរិបទនៃច្បាប់បូកស្ពែន។ ទីបំផុត ការព្យាករណ៍ខ្លះអំពីតម្លៃដែលអាចសង្កេតបាន អាស៊ីម៉េទ្រី និងកាត់កាត់ត្រូវបានផ្តល់ឱ្យក្នុងដំណើរការ (i)-(iii)។ ពួកវាសំខាន់ចំពោះការពិសោធន៍ដែលមានគម្រោងជាមួយម៉ាស៊ីនបំបែកគោលកម្មវិធី HERA និងម៉ាស៊ីនបុកបំបែកបន្ទាត់ ដែលនឹងស្វែងរកតំបន់ដែលមានតម្លៃទាបនៃ Bjorken $x$។
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Massive rotating single stars with an initial metal composition appropriate for the dwarf galaxy I Zw 18 ([Fe/H]=$-$1.7) are modelled during hydrogen burning for initial masses of 9-300 M$_{\odot}$ and rotational velocities of 0-900 km s$^{-1}$. Internal mixing processes in these models were calibrated based on an observed sample of OB-type stars in the Magellanic Clouds. Even moderately fast rotators, which may be abundant at this metallicity, are found to undergo efficient mixing induced by rotation resulting in quasi chemically-homogeneous evolution. These homogeneously-evolving models reach effective temperatures of up to 90 kK during core hydrogen burning. This, together with their moderate mass-loss rates, make them Transparent Wind Ultraviolet INtense stars (TWUIN star), and their expected numbers might explain the observed HeII ionizing photon flux in I Zw 18 and other low-metallicity HeII galaxies. Our slowly rotating stars above $\sim$80 M$_{\odot}$ evolve into late B- to M-type supergiants during core hydrogen burning, with visual magnitudes up to 19$^{\mathrm{m}}$ at the distance of I Zw 18. Both types of stars, TWUIN stars and luminous late-type supergiants, are only predicted at low metallicity. Massive star evolution at low metallicity is shown to differ qualitatively from that in metal-rich environments. Our grid can be used to interpret observations of local star-forming dwarf galaxies and high-redshift galaxies, as well as the metal-poor components of our Milky Way and its globular clusters.
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Stelle singole massicce in rotazione con una composizione iniziale di metalli appropriata per la galassia nana I Zw 18 ([Fe/H]=$-$1,7) sono state modellizzate durante la fase di combustione dell'idrogeno per masse iniziali comprese tra 9 e 300 M$_{\odot}$ e velocità di rotazione comprese tra 0 e 900 km s$^{-1}$. I processi di mescolamento interno in questi modelli sono stati calibrati sulla base di un campione osservato di stelle di tipo OB nelle Nubi di Magellano. Si è riscontrato che anche rotatori moderatamente veloci, che potrebbero essere abbondanti a questa metallicità, subiscono un efficiente mescolamento indotto dalla rotazione, risultando in un'evoluzione quasi chimicamente omogenea. Questi modelli con evoluzione omogenea raggiungono temperature efficaci fino a 90 kK durante la combustione dell'idrogeno nel nucleo. Ciò, unito ai loro tassi moderati di perdita di massa, li rende stelle Transparent Wind Ultraviolet INtense (stelle TWUIN), e il loro numero previsto potrebbe spiegare il flusso osservato di fotoni ionizzanti HeII in I Zw 18 e in altre galassie HeII a bassa metallicità. Le nostre stelle lentamente rotanti con masse superiori a $\sim$80 M$_{\odot}$ evolvono in supergiganti di tipo B tardo fino a tipo M durante la combustione dell'idrogeno nel nucleo, con magnitudini visibili fino a 19$^{\mathrm{m}}$ alla distanza di I Zw 18. Entrambi i tipi di stelle, le stelle TWUIN e le supergiganti luminose di tipo spettrale tardo, sono previsti soltanto a bassa metallicità. Si dimostra che l'evoluzione delle stelle massicce a bassa metallicità differisce qualitativamente da quella in ambienti ricchi di metalli. La nostra griglia può essere utilizzata per interpretare osservazioni di galassie nane con formazione stellare locale e galassie ad alto redshift, nonché le componenti povere di metalli della nostra Via Lattea e dei suoi ammassi globulari.
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We study the dynamical evolution of spiral structure in the stellar disks of isolated galaxies using high resolution Smoothed Particle Hydrodynamics (SPH) simulations that treat the evolution of gas, stars, and dark matter self-consistently. We focus this study on the question of self-excited spiral structure in the stellar disk and investigate the dynamical coupling between the cold, dissipative gaseous component and the stellar component. We find that angular momentum transport from the gas to the stars inside of corotation leads to a roughly time-steady spiral structure in the stellar disk. To make this point clear, we contrast these results with otherwise identical simulations that do not include a cold gaseous component that is able to cool radiatively and dissipate energy, and find that spiral structure, when it is incipient, dies out more rapidly in simulations that do not include gas. We also employ a standard star formation prescription to convert gas into stars and find that our results hold for typical gas consumption time scales that are in accord with the Kennicutt-Schmidt relation. We therefore attribute the long-lived roughly time steady spiral structure in the stellar disk to the dynamical coupling between the gas and the stars and the resultant torques that the self-gravitating gaseous disk is able to exert on the stars due to an azimuthal phase shift between the collisionless and dissipative components.
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យើងសិក្សាអំពីវិវត្តន៍ដែលមានចលនារបស់រចនាសម្ព័ន្ធសព្វរន្ធ (spiral structure) នៅក្នុងថាសផ្កាយរបស់ហ្គាឡាក់ស៊ីដាច់ដោយឡែក ដោយប្រើការធ្វើម៉ូដែលដែលមានកម្រិតលម្អិតខ្ពស់ដោយប្រើវិធីសាស្ត្រ Smoothed Particle Hydrodynamics (SPH) ដែលពិចារណាពីវិវត្តន៍របស់ឧស្ម័ន ផ្កាយ និងសារធាតុងងឹតដោយស៊ីសង្វាក់គ្នា។ យើងផ្តោតការសិក្សានេះលើសំណួរអំពីរចនាសម្ព័ន្ធសព្វរន្ធដែលបង្កើតឡើងដោយខ្លួនវាផ្ទាល់នៅក្នុងថាសផ្កាយ ហើយសិក្សាអំពីការភ្ជាប់គ្នាដោយចលនារវាងគ្រាប់ផ្កាយដែលមានសីតុណ្ហភាពទាប និងមានលក្ខណៈរាវនៃឧស្ម័ន និងគ្រាប់ផ្កាយ។ យើងរកឃើញថាការផ្ទេរចលនាថាមពលពីឧស្ម័នទៅផ្កាយនៅខាងក្នុងតំបន់ corotation បណ្តាលឱ្យមានរចនាសម្ព័ន្ធសព្វរន្ធដែលស្ថិតក្នុងស្ថានភាពស្ថិតស្ថេរប្រហែលថេរតាមពេលវេលានៅក្នុងថាសផ្កាយ។ ដើម្បីបញ្ជាក់ចំណុចនេះឱ្យកាន់តែច្បាស់ យើងធ្វើការប្រៀបធៀបលទ្ធផលទាំងនេះជាមួយការធ្វើម៉ូដែលដែលស្រដៀងគ្នាប៉ុន្តែដោយគ្មានគ្រាប់ឧស្ម័នដែលអាចត្រជាក់តាមរយៈការរេដៀក់ និងរាវថាមពលបាន ហើយរកឃើញថារចនាសម្ព័ន្ធសព្វរន្ធ នៅពេលដែលវាចាប់ផ្តើម វារលាយបាត់យ៉ាងរហ័សក្នុងការធ្វើម៉ូដែលដែលគ្មានឧស្ម័ន។ យើងក៏ប្រើវិធីសាស្ត្រស្តង់ដារក្នុងការបង្កើតផ្កាយដើម្បីបំលែងឧស្ម័នទៅជាផ្កាយ ហើយរកឃើញថាលទ្ធផលរបស់យើងនៅតែជាក់ស្តែងសម្រាប់រយៈពេលប្រើប្រាស់ឧស្ម័នធម្មតា ដែលស័ក្តិសមនឹងទំនាក់ទំនងKennicutt-Schmidt។ ដូច្នេះ យើងសន្មត់ថារចនាសម្ព័ន្ធសព្វរន្ធដែលរស់រានមានអាយុវែង និងស្ថិតក្នុងស្ថានភាពស្ថិតស្ថេរប្រហែលថេរតាមពេលវេលានៅក្នុងថាសផ្កាយ គឺដោយសារការភ្ជាប់គ្នាដោយចលនារវាងឧស្ម័ន និងផ្កាយ និងដោយសារកម្លាំងបង្វិលដែលថាសឧស្ម័នដែលមានទំនាញខ្លួនឯងអាចបង្កើតបានលើផ្កាយ ដោយសារការផ្លាស់ទីមុំជា azimuthal រវាងគ្រាប់ដែលគ្មានការប៉ះទង្គិច និងគ្រាប់ដែលមានលក្ខណៈរាវ។
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The space of invariant affine connections on every $3$-Sasakian homogeneous manifold of dimension at least $7$ is described. In particular, the remarkable subspaces of invariant affine metric connections, and the subclass with skew-torsion, are also determined. To this aim, an explicit construction of all $3$-Sasakian homogeneous manifolds is exhibited. The unique $3$-Sasakian homogeneous manifolds which admit nontrivial Einstein with skew-torsion invariant affine connections are those of dimension $7$, that is, $\mathbb{S}^7=\mathrm{Sp} (2)/ \mathrm{Sp(1)}$, $\mathbb{R} P^7=\mathrm{Sp}(2)/ \mathrm{Sp(1)}\times \mathbb{Z}_{2}$ and the Aloff-Wallach space $\mathfrak{W}^{7}_{1,1}= \mathrm{SU}(3)/ \mathrm{U}(1)$. For $\mathbb{S}^7$ and $\mathbb{R} P^7$, the set of such connections is in one to one correspondence with two copies of the conformal linear transformation group of the Euclidean space, while it is strictly bigger for $\mathfrak{W}^{7}_{1,1}$. In addition, the set of invariant connections with totally skew-symmetric torsion whose Ricci tensor is multiple of the metric, with different factors, on the canonical vertical and horizontal distributions, is fully described on every $3$-Sasakian homogeneous manifold. An affine connection satisfying these conditions is distinguished, characterized by parallelizing all the characteristic vector fields associated to the $3$-Sasakian structure. This connection is Einstein with skew-torsion for the $7$-dimensional examples. Several results have also been adapted to the nonnecessarily homogeneous setting. In this case, the above mentioned sets of affine connections are, in general, only proper subsets satisfying the properties.
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O espaço das conexões afins invariantes em toda variedade homogênea 3-Sasakiana de dimensão pelo menos 7 é descrito. Em particular, determinam-se também os subespaços notáveis das conexões afins métricas invariantes, bem como a subclasse com torção antissimétrica. Para tanto, apresenta-se uma construção explícita de todas as variedades homogêneas 3-Sasakianas. As únicas variedades homogêneas 3-Sasakianas que admitem conexões afins invariantes não triviais do tipo Einstein com torção antissimétrica são aquelas de dimensão 7, isto é, $\mathbb{S}^7=\mathrm{Sp}(2)/\mathrm{Sp(1)}$, $\mathbb{R} P^7=\mathrm{Sp}(2)/\mathrm{Sp(1)}\times \mathbb{Z}_{2}$ e o espaço de Aloff-Wallach $\mathfrak{W}^{7}_{1,1}= \mathrm{SU}(3)/ \mathrm{U}(1)$. Para $\mathbb{S}^7$ e $\mathbb{R} P^7$, o conjunto dessas conexões está em correspondência biunívoca com duas cópias do grupo de transformações lineares conformes do espaço euclidiano, enquanto que para $\mathfrak{W}^{7}_{1,1}$ é estritamente maior. Além disso, descreve-se completamente o conjunto das conexões invariantes com torção totalmente antissimétrica cujo tensor de Ricci é múltiplo da métrica, com fatores distintos, nas distribuições vertical e horizontal canônicas, em toda variedade homogênea 3-Sasakiana. Uma conexão afim que satisfaz essas condições destaca-se, caracterizada por paralelizar todos os campos vetoriais característicos associados à estrutura 3-Sasakiana. Essa conexão é do tipo Einstein com torção antissimétrica nos exemplos de dimensão 7. Diversos resultados também foram adaptados ao contexto não necessariamente homogêneo. Nesse caso, os conjuntos acima mencionados de conexões afins são, em geral, apenas subconjuntos próprios que satisfazem as propriedades.
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We study classical and quantum hidden symmetries of a particle with electric charge $e$ in the background of a Dirac monopole of magnetic charge $g$ subjected to an additional central potential $V(r)=U(r) +(eg)^2/2mr^{2}$ with $U(r)=\tfrac{1}{2}m\omega^2r^2$, similar to that in the one-dimensional conformal mechanics model of de Alfaro, Fubini and Furlan (AFF). By means of a non-unitary conformal bridge transformation, we establish a relation of the quantum states and of all symmetries of the system with those of the system without harmonic trap, $U(r)=0$. Introducing spin degrees of freedom via a very special spin-orbit coupling, we construct the $\mathfrak{osp}(2,2)$ superconformal extension of the system with unbroken $\mathcal{N}=2$ Poincar\'e supersymmetry and show that two different superconformal extensions of the one-dimensional AFF model with unbroken and spontaneously broken supersymmetry have a common origin. We also show a universal relationship between the dynamics of a Euclidean particle in an arbitrary central potential $U(r)$ and the dynamics of a charged particle in a monopole background subjected to the potential $V(r)$.
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Sinusuri namin ang mga klasikal at kwantum na nakatagong simetria ng isang partikulo na may elektrikong singa $e$ sa likod ng isang Dirac monopole na may magnetikong singa na $g$ na napapailalim sa karagdagang sentral na potensyal na $V(r)=U(r) +(eg)^2/2mr^{2}$ kung saan $U(r)=\tfrac{1}{2}m\omega^2r^2$, na katulad ng potensyal sa isang-dimensyonal na modelo ng pangsinga na mekaniks ni de Alfaro, Fubini at Furlan (AFF). Sa pamamagitan ng isang hindi unitary na pangsinga na pagbabagong-boses, itinatag namin ang ugnayan ng mga kwantum na estado at ng lahat ng simetria ng sistema sa sistema naman na walang harmonic trap, $U(r)=0$. Sa pamamagitan ng pagpapakilala ng mga antas ng pag-ikot (spin degrees of freedom) gamit ang isang napakalalong espesyal na spin-orbit coupling, binuo namin ang $\mathfrak{osp}(2,2)$ superpangsinga na pagpapalawig ng sistema na may buong $\mathcal{N}=2$ Poincar\'e supersymmetry at ipinakita na ang dalawang magkaibang superpangsinga na pagpapalawig ng isang-dimensyonal na modelo ni AFF na may buong at boluntaryong nabasag na supersymmetry ay may iisang pinagmulan. Ipakikita rin namin ang isang pangkalahatang ugnayan sa pagitan ng dinamika ng isang Euclidean na partikulo sa isang arbitraryong sentral na potensyal na $U(r)$ at ang dinamika ng isang singadong partikulo sa isang monopole na likuran na napapailalim sa potensyal na $V(r)$.
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tl
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We investigate dust entrainment by photoevaporative winds in protoplanetary discs using dusty smoothed particle hydrodrodynamics (SPH). We use unequal-mass particles to resolve more than five orders of magnitude in disc/outflow density and a one-fluid formulation to efficiently simulate an equivalent magnitude range in drag stopping time. We find that only micron sized dust grains and smaller can be entrained in EUV driven winds. The maximum grain size is set by dust settling in the disc rather than aerodynamic drag in the wind. More generally, there is a linear relationship between the base flow density and the maximum entrainable grain size in the wind. A pileup of micron sized dust grains can occur in the upper atmosphere at critical radii in the disc as grains decouple from the low-density wind. Entrainment is a strong function of location in the disc, resulting in a size sorting of grains in the outflow---the largest grain being carried out between $10$--$20\,$AU. The peak dust density for each grain size occurs at the inner edge of its own entrainment region.
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Nous étudions l'entraînement de poussière par des vents photoévaporatifs dans les disques protoplanétaires à l'aide de la méthode hydrodynamique particulaires lissée (SPH) avec poussière. Nous utilisons des particules de masses inégales afin de résoudre plus de cinq ordres de grandeur en densité entre le disque et l'éjection, ainsi qu'une formulation monofluide pour simuler efficacement une plage équivalente en temps de freinage dû au drag. Nous constatons que seuls les grains de poussière d'une taille inférieure ou égale au micron peuvent être entraînés par des vents induits par le rayonnement EUV. La taille maximale des grains est déterminée par leur tassement dans le disque plutôt que par la traînée aérodynamique dans le vent. Plus généralement, une relation linéaire existe entre la densité du flux de base et la taille maximale des grains pouvant être entraînés dans le vent. Un accumulement de grains de poussière de taille micronique peut se produire dans la haute atmosphère, aux rayons critiques du disque, lorsque les grains se découplent du vent de faible densité. L'entraînement dépend fortement de la position dans le disque, entraînant un tri par taille des grains dans l'éjection : les plus gros grains étant expulsés entre $10$ et $20\,$UA. La densité maximale de poussière pour chaque taille de grain se situe au bord interne de sa propre zone d'entraînement.
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fr
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We investigate dust entrainment by photoevaporative winds in protoplanetary discs using dusty smoothed particle hydrodrodynamics (SPH). We use unequal-mass particles to resolve more than five orders of magnitude in disc/outflow density and a one-fluid formulation to efficiently simulate an equivalent magnitude range in drag stopping time. We find that only micron sized dust grains and smaller can be entrained in EUV driven winds. The maximum grain size is set by dust settling in the disc rather than aerodynamic drag in the wind. More generally, there is a linear relationship between the base flow density and the maximum entrainable grain size in the wind. A pileup of micron sized dust grains can occur in the upper atmosphere at critical radii in the disc as grains decouple from the low-density wind. Entrainment is a strong function of location in the disc, resulting in a size sorting of grains in the outflow---the largest grain being carried out between $10$--$20\,$AU. The peak dust density for each grain size occurs at the inner edge of its own entrainment region.
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Studiamo il trascinamento della polvere da parte di venti fotoevaporativi nei dischi protoplanetari utilizzando la dinamica dei fluidi a particelle lisce (SPH) polverosa. Utilizziamo particelle di massa disuguale per risolvere più di cinque ordini di grandezza nella densità del disco/efflusso e una formulazione monofluido per simulare in modo efficiente un intervallo equivalente nel tempo di arresto dovuto alla resistenza aerodinamica. Scopriamo che soltanto le particelle di polvere di dimensioni micrometriche o inferiori possono essere trascinate dai venti generati da radiazione EUV. La dimensione massima delle particelle è determinata dal sedimentarsi della polvere nel disco piuttosto che dalla resistenza aerodinamica nel vento. Più in generale, esiste una relazione lineare tra la densità del flusso alla base e la dimensione massima delle particelle trascinabili nel vento. Può verificarsi un accumulo di particelle di dimensioni micrometriche nell'atmosfera superiore alle distanze radiali critiche nel disco, quando le particelle si disaccoppiano dal vento a bassa densità. Il trascinamento dipende fortemente dalla posizione nel disco, determinando una separazione per dimensione delle particelle nell'efflusso: le particelle più grandi vengono espulse tra $10$ e $20\,$UA. La densità massima di polvere per ciascuna dimensione delle particelle si verifica al bordo interno della propria regione di trascinamento.
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it
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To constrain a contribution of deep carbonated mantle, to fractionation of Hf relative to rare earth elements (REE) in volcanic series, we examine available high-quality data on major, trace element and Nd-Hf isotope compositions of primitive lavas and glasses erupted during preshield, postshield and mostly rejuvenated stage of the Hawaiian hot spot (Pacific Ocean). Strong variations of Hf/Sm, Zr/Sm, Ti/Eu, K/Th, Nb/Th, La/K and Ba/K in the lavas are not features of the melt equilibration with residual amphibole or phlogopite, and cannot be due to variable degrees of batch or dynamic melting of uncarbonated lherzolite source. Enrichment in REE, Th and Ba relative to K, Hf, Zr, Ti and Nb together and low Si, high Na, K and Ca contents in the Hawaiian lavas are compositional features of carbonated mantle lithospheric to asthenospheric peridotite source affected by carbonatite metasomatism. In contrast, major and trace element signatures of most primitive preshield- and postshield-stage magmas require pyroxenite source. The available data infer that Salt Lake Crater garnet pyroxenite xenoliths hosted by the Koolau volcano lavas on Oahu, Hawaii, were derived from deep eclogite source likely generating the carbonatite melts within the Hawaiian plume. Highly radiogenic Hf and decoupled Nd-Hf isotope systematics recorded in the Salt Lake Crater mantle xenolith series on Oahu may be explained by strong Hf fractionation relative to REE owing to ancient event of carbonatite metasomatism, which is likely related to partial melting of the deeply subducted carbonated eclogite within the Hawaiian plume.
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ដើម្បីកំណត់ការចូលរួមរបស់ផ្នែកដីថ្មដែលមានកាបូនាតជ្រៅ និងការបំបែកអ៊ីសូតូប Hf ធៀបនឹងធាតុដីកម្រ (REE) ក្នុងស៊េរីភ្នំភ្លើង យើងបានសិក្សាទិន្នន័យដែលមានគុណភាពខ្ពស់អំពីធាតុធំៗ ធាតុតូចៗ និងសមាសភាពអ៊ីសូតូប Nd-Hf របស់ថ្មរាវ និងកញ្ចក់ដែលបានផ្ទះពីដំណាក់កាលមុនពេលរុញឡើង ក្រោយពេលរុញឡើង និងជាច្រើនតែដំណាក់កាលបន្តបន្ទាប់នៃកន្លែងក្តៅហាវ៉ៃ (មហាសមុទ្រប៉ាស៊ីហ្វិក)។ ការប្រែប្រួលខ្លាំងនៃសមាមាត្រ Hf/Sm, Zr/Sm, Ti/Eu, K/Th, Nb/Th, La/K និង Ba/K ក្នុងថ្មរាវមិនមែនជាលក្ខណៈរបស់ដំណើររលាយសម្របសម្រួលជាមួយអំបិលអាមផ៊ីបូល ឬផ្លូហ្គូព៉ៃត និងក៏មិនអាចបណ្តាលមកពីកម្រិតរលាយមិនស្មើគ្នា ឬការរលាយដោយមានចលនារបស់ប្រភពថ្មលឺហ្សូលីតដែលគ្មានកាបូនាតនោះដែរ។ ការបំពេញបន្ថែមនៃធាតុដីកម្រ (REE), Th និង Ba ធៀបនឹង K, Hf, Zr, Ti និង Nb រួមគ្នា និងការមានសារធាតុ Si ទាប និង Na, K និង Ca ខ្ពស់ក្នុងថ្មរាវហាវ៉ៃ គឺជាលក្ខណៈសម្បត្តិគីមីរបស់ប្រភពថ្មប៉េរ៉ូដូតីតដែលមានកាបូនាត ពីថ្នាំងផ្នែកដីទៅអាសថេណូស្វែរ ដែលបានទទួលរងឥទ្ធិពលពីការប្រែប្រួលដោយកាបូនាត។ ផ្ទុយពីនេះ សញ្ញាគីមីធាតុធំៗ និងធាតុតូចៗរបស់ម៉ាញ៉ាដំបូងបំផុតក្នុងដំណាក់កាលមុនរុញឡើង និងក្រោយរុញឡើង ទាមទារឲ្យមានប្រភពថ្មពីរុយសែនីត។ ទិន្នន័យដែលមានស្រាប់បង្ហាញថា គំរូថ្មចេញពីប្រភពហ្គាន់នែត-ពីរុយសែនីតនៃអាងភ្នំភ្លើងស៊ើលលែកខ្សាច់ ដែលស្ថិតនៅក្នុងថ្មរាវភ្នំគូឡៅ នៅអ៊ូអាហ្វូ ហាវ៉ៃ បានមកពីប្រភពអ៊ិកឡូហ្ស៊ីតជ្រៅ ដែលប្រហែលជាបង្កើតជារាវកាបូនាតនៅក្នុងដំបូកហាវ៉ៃ។ សញ្ញាអ៊ីសូតូប Hf ដែលមានការវិវត្តខ្លាំង និងប្រព័ន្ធអ៊ីសូតូប Nd-Hf ដែលមិនភ្ជាប់គ្នា ដែលត្រូវបានកត់ត្រាក្នុងស៊េរីគំរូថ្មផ្នែកដីនៃអាងភ្នំភ្លើងស៊ើលលែកខ្សាច់ នៅអ៊ូអាហ្វូ អាចពន្យល់បានដោយការបំបែកអ៊ីសូតូប Hf ខ្លាំងធៀបនឹងធាតុដីកម្រ ដោយសារព្រឹត្តិការណ៍បុរាណនៃការប្រែប្រួលដោយកាបូនាត ដែលប្រហែលជាទាក់ទងនឹងការរលាយផ្នែកដោយថ្មអ៊ិកឡូហ្ស៊ីតដែលមានកាបូនាតជ្រៅនៅក្នុងដំបូកហាវ៉ៃ។
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km
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Choosing a decision threshold is one of the challenging job in any classification tasks. How much the model is accurate, if the deciding boundary is not picked up carefully, its entire performance would go in vain. On the other hand, for imbalance classification where one of the classes is dominant over another, relying on the conventional method of choosing threshold would result in poor performance. Even if the threshold or decision boundary is properly chosen based on machine learning strategies like SVM and decision tree, it will fail at some point for dynamically varying databases and in case of identity-features that are more or less similar, like in face recognition and person re-identification models. Hence, with the need for adaptability of the decision threshold selection for imbalanced classification and incremental database size, an online optimization-based statistical feature learning adaptive technique is developed and tested on the LFW datasets and self-prepared athletes datasets. This method of adopting adaptive threshold resulted in 12-45% improvement in the model accuracy compared to the fixed threshold {0.3,0.5,0.7} that are usually taken via the hit-and-trial method in any classification and identification tasks. Source code for the complete algorithm is available at: https://github.com/Varat7v2/adaptive-threshold
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Việc lựa chọn ngưỡng quyết định là một trong những công việc thách thức trong mọi tác vụ phân loại. Dù mô hình có độ chính xác cao đến đâu, nếu ranh giới quyết định không được chọn cẩn thận thì toàn bộ hiệu suất của nó sẽ trở nên vô ích. Mặt khác, đối với bài toán phân loại mất cân bằng, trong đó một lớp chiếm ưu thế hơn lớp còn lại, việc dựa vào phương pháp truyền thống để chọn ngưỡng sẽ dẫn đến hiệu suất kém. Ngay cả khi ngưỡng hay ranh giới quyết định được chọn đúng cách dựa trên các chiến lược học máy như SVM và cây quyết định, phương pháp này vẫn thất bại ở một số điểm đối với các cơ sở dữ liệu thay đổi động và trong trường hợp các đặc trưng nhận dạng giống nhau nhiều hay ít, như trong các mô hình nhận dạng khuôn mặt và nhận dạng lại người. Do đó, nhằm đáp ứng nhu cầu về khả năng thích ứng trong việc lựa chọn ngưỡng quyết định đối với phân loại mất cân bằng và kích thước cơ sở dữ liệu tăng dần, một kỹ thuật học đặc trưng thống kê thích ứng dựa trên tối ưu hóa trực tuyến đã được phát triển và kiểm nghiệm trên các bộ dữ liệu LFW và các bộ dữ liệu vận động viên do chúng tôi tự chuẩn bị. Phương pháp áp dụng ngưỡng thích ứng này đã mang lại sự cải thiện từ 12-45% về độ chính xác của mô hình so với ngưỡng cố định {0,3; 0,5; 0,7} thường được chọn theo phương pháp thử và sai trong mọi tác vụ phân loại và nhận dạng. Mã nguồn cho toàn bộ thuật toán có sẵn tại: https://github.com/Varat7v2/adaptive-threshold
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vi
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In this paper a Gaussian impurity moving through an equilibrium Bose-Einstein condensate at T = 0 is studied. The problem can be described by a Gross-Pitaevskii equation, which is solved perturbatively. The analysis is done for systems of 2 and 3 spatial dimensions and generalises the work by [G.E. Astrakharchik and L.P. Pitaevskii, Phys. Rev. A 70, 013608 (2004)]. The Bogoliubov equation solutions for the condensate perturbed by a finite impurity are calculated in the co-moving frame, which are formally equivalent up to a dimension dependent form factor for general dimensions. From those solutions the total energy of the perturbed system is determined as a function of the width and the amplitude of the moving Gaussian impurity and its velocity. Finally we derive the drag force the Gaussian impurity approximately experiences as it moves through the superfluid, which proofs the existence of a superfluid phase for finite extensions of the impurities below the speed of sound and that the force increases monotonically with velocity until it decreases again.
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এই গবেষণাপত্রে T = 0 তাপমাত্রায় একটি সাম্যাবস্থার বোস-আইনস্টাইন ঘনীভবনের মধ্য দিয়ে চলমান একটি গাউসীয় অশুদ্ধি নিয়ে আলোচনা করা হয়েছে। এই সমস্যাটিকে একটি গ্রস-পিতাভস্কি সমীকরণ দ্বারা বর্ণনা করা যায়, যা বাধাদান পদ্ধতিতে সমাধান করা হয়। এই বিশ্লেষণটি 2 এবং 3 মাত্রার ব্যবস্থার জন্য করা হয়েছে এবং [G.E. আস্ত্রাখারচিক এবং L.P. পিতাভস্কি, ফিজ. রেভ. A 70, 013608 (2004)]-এর কাজকে সাধারণীকরণ করে। সসীম অশুদ্ধি দ্বারা বিকৃত ঘনীভবনের জন্য বোগোলিউবোভ সমীকরণের সমাধানগুলি চলমান ফ্রেমে গণনা করা হয়, যা আনুপাতিকভাবে সাধারণ মাত্রার জন্য মাত্রার উপর নির্ভরশীল একটি ফর্ম ফ্যাক্টর পর্যন্ত সমতুল্য। এই সমাধানগুলি থেকে বিকৃত ব্যবস্থার মোট শক্তিকে গতিশীল গাউসীয় অশুদ্ধির প্রস্থ, বিস্তার এবং তার বেগের ফাংশন হিসাবে নির্ধারণ করা হয়। অবশেষে, গাউসীয় অশুদ্ধির উপর ঘর্ষণ বলের আসন্ন মান নির্ণয় করা হয় যা অতিপ্রবাহীর মধ্য দিয়ে চলার সময় অশুদ্ধির উপর ক্রিয়া করে, যা শব্দের গতির নিচে অশুদ্ধির সসীম বিস্তারের জন্য অতিপ্রবাহী অবস্থার অস্তিত্বকে প্রমাণ করে এবং এটিও প্রমাণ করে যে বলটি বেগের সাথে একঘেয়েভাবে বৃদ্ধি পায় এবং পরে আবার হ্রাস পায়।
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bn
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Computational procedures to foresee the 3D structure of aptamers are in continuous progress. They constitute a crucial input to research, mainly when the crystallographic counterpart of the structures in silico produced is not present. At now, many codes are able to perform structure and binding prediction, although their ability in scoring the results remains rather weak. In this paper, we propose a novel procedure to complement the ranking outcomes of free docking code, by applying it to a set of anti-angiopoietin aptamers, whose performances are known. We rank the in silico produced configurations, adopting a maximum likelihood estimate, based on their topological and electrical properties. From the analysis, two principal kinds of conformers are identified, whose ability to mimick the binding features of the natural receptor is discussed. The procedure is easily generalizable to many biological biomolecules, useful for increasing chances of success in designing high-specificity biosensors (aptasensors).
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Les procédures informatiques permettant de prédire la structure 3D des aptamères progressent continuellement. Elles constituent un apport essentiel à la recherche, principalement lorsque la contrepartie cristallographique des structures produites in silico n'est pas disponible. À l'heure actuelle, de nombreux logiciels sont capables d'effectuer des prédictions de structure et de liaison, bien que leur capacité à évaluer la qualité des résultats reste plutôt limitée. Dans cet article, nous proposons une nouvelle procédure visant à compléter les résultats de classement d'un logiciel de docking libre, en l'appliquant à un ensemble d'aptamères anti-angiopoïétine dont les performances sont connues. Nous classons les configurations produites in silico en adoptant une estimation par maximum de vraisemblance, fondée sur leurs propriétés topologiques et électriques. L'analyse permet d'identifier deux types principaux de conformères, et la capacité de ceux-ci à imiter les caractéristiques de liaison du récepteur naturel est discutée. La procédure est facilement généralisable à de nombreuses biomolécules biologiques, et utile pour augmenter les chances de succès dans la conception de biocapteurs à haute spécificité (aptasenseurs).
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fr
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The prompt optical emission of GRB 990123 was uncorrelated to the gamma-ray light-curve and exhibited temporal properties similar to those of the steeply-decaying, early X-ray emission observed by Swift at the end of many bursts. These facts suggest that the optical counterpart of GRB 990123 was the large-angle emission released during (the second pulse of) the burst. If the optical and gamma-ray emissions of GRB 990123 have, indeed, the same origin then their properties require that (i) the optical counterpart was synchrotron emission and the gamma-rays arose from inverse-Compton scatterings ("synchrotron self-Compton model"), (ii) the peak-energy of the optical-synchrotron component was at ~20 eV, and (iii) the burst emission was produced by a relativistic outflow moving at Lorentz factor > 450 and at a radius > 10^{15} cm, which is comparable to the outflow deceleration radius. Because the spectrum of GRB 990123 was optically thin above 2 keV, the magnetic field behind the shock must have decayed on a length-scale of <1% of the thickness of the shocked gas, which corresponds to 10^6-10^7 plasma skin-depths. Consistency of the optical counterpart decay rate and its spectral slope (or that of the burst, if they represent different spectral components) with the expectations for the large-angle burst emission represents the most direct test of the unifying picture proposed here for GRB 990123.
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L'emissione ottica precoce del GRB 990123 non era correlata alla curva di luce in raggi gamma ed esibiva proprietà temporali simili a quelle dell'emissione X iniziale in rapido decadimento osservata da Swift alla fine di molti burst. Questi fatti suggeriscono che la controparte ottica del GRB 990123 fosse l'emissione a grande angolo rilasciata durante (il secondo impulso del) burst. Se le emissioni ottica e gamma del GRB 990123 hanno effettivamente la stessa origine, allora le loro proprietà richiedono che (i) la controparte ottica fosse emissione sincrotrone e i raggi gamma derivassero da scattering Compton inverso ("modello Compton inverso auto-sincrotrone"), (ii) l'energia di picco della componente sincrotrone ottica fosse a ~20 eV, e (iii) l'emissione del burst fosse prodotta da un flusso relativistico in espansione con fattore di Lorentz maggiore di 450 e a un raggio maggiore di 10^{15} cm, valore paragonabile al raggio di decelerazione del flusso. Poiché lo spettro del GRB 990123 era otticamente sottile al di sopra di 2 keV, il campo magnetico a valle dell'urto deve essersi attenuato su una scala spaziale inferiore all'1% dello spessore del gas urtato, corrispondente a 10^6-10^7 lunghezze di pelle del plasma. La coerenza tra il tasso di decadimento della controparte ottica e la sua pendenza spettrale (o quella del burst, se esse rappresentano componenti spettrali diverse) con le previsioni relative all'emissione del burst a grande angolo rappresenta il test più diretto dell'immagine unificata qui proposta per il GRB 990123.
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it
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We use a representative sample of 65 galaxy clusters observed with the Einstein IPC to constrain the range of cluster X-ray morphologies. We develop and apply quantitative and reproducible measures to constrain the intrinsic distributions of emission weighted centroid variation, axial ratio, orientation, and the radial fall--off. We then use the range of cluster X--ray morphologies to constrain three generic cosmological models (Omega=1, Omega_0=0.2, and Omega_0=0.2 & lambda_0=0.8). For each of these models, we evolve eight sets of Gaussian random initial conditions consistent with an effective power spectrum $P(k)\propto k^{-1}$ on cluster scales. Using this sample of 24 numerical cluster simulations, we compare the X--ray morphologies of the observed and simulated clusters. The comparisons indicate that: (i) cluster centroid variations, axial ratios, and radial fall-offs are sensitive to the underlying cosmological model, and (ii) galaxy clusters with the observed range of X--ray morphologies are very unlikely in low Omega_0 cosmologies. The analysis favors the Omega=1 model, though some discrepancies remain. We discuss the effects of changing the initial conditions and including additional physics in the simulations.
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ہم آئن سٹائن آئی پی سی کے ساتھ مشاہدہ کیے گئے 65 کہکشانی کلچرز کے ایک نمائندہ نمونے کو کلچرز کی ایکس رے ہیئت کی حد کو محدود کرنے کے لیے استعمال کرتے ہیں۔ ہم اخراج وزنی سنٹرآئیڈ تبدیلی، محوری تناسب، سمت اور شعاعی کمی کے ذاتی تقسیم کو محدود کرنے کے لیے مقداری اور دہرائے جانے والے پیمانوں کو تیار کرتے ہیں اور ان کا اطلاق کرتے ہیں۔ پھر ہم کلچرز کی ایکس رے ہیئت کی حد کو تین عمومی کاسمولوجیکل ماڈلز (Omega=1، Omega_0=0.2، اور Omega_0=0.2 و lambda_0=0.8) کو محدود کرنے کے لیے استعمال کرتے ہیں۔ ان ماڈلز میں سے ہر ایک کے لیے، ہم کلچر اسکیلز پر موثر پاور اسپیکٹرم $P(k)\propto k^{-1}$ کے مطابق گاؤسی تصادفی ابتدائی حالات کے آٹھ سیٹس کو ترقی دیتے ہیں۔ اس 24 عددی کلچر مآخذ کے نمونے کا استعمال کرتے ہوئے، ہم مشاہدہ شدہ اور ماخوذ کلچرز کی ایکس رے ہیئت کا موازنہ کرتے ہیں۔ یہ موازنہ یہ اشارہ کرتا ہے کہ: (i) کلچر کے سنٹرآئیڈ تغیرات، محوری تناسب، اور شعاعی کمی بنیادی کاسمولوجیکل ماڈل پر منحصر ہوتے ہیں، اور (ii) کم Omega_0 کاسمولوجیز میں مشاہدہ کردہ ایکس رے ہیئت کی حد کے ساتھ کہکشانی کلچرز بہت غیر ممکن ہیں۔ تجزیہ Omega=1 ماڈل کی حمایت کرتا ہے، اگرچہ کچھ اختلافات باقی ہیں۔ ہم مآخذ میں ابتدائی حالات میں تبدیلی اور اضافی طبیعیات کو شامل کرنے کے اثرات پر بحث کرتے ہیں۔
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ur
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