Vitor Cardoso, Jaime Redondo-Yuste, Ulrich Sperhake
et al.
Black holes and gravitational waves are consequences of the nonlinear character of the Einstein equations. Yet, the remarkable properties of General Relativity point to the existence of other effects. Here we uncover new nonlinear facets of gravity. We establish higher harmonic generation, spectral broadening and focusing in the Einstein Klein-Gordon system. In vacuum, we show that scattering of monochromatic waves at quadratic order is weakly sensitive to frequency, at large wavelengths. These aspects can both explain the seemingly smooth behavior of mergers, but also caution us against too simplistic an interpretation of waveforms.
In this work, we study a cosmological model driven by Generalized ModMax nonlinear electrodynamics. We find that, with an appropriate choice of the theory's parameters, the universe's initial singularity can be avoided. Moreover, we also find that this model has an inflationary epoch that is consistent with the current values for $N$, $n_s$ and $r$. Therefore, using Generalized ModMax, we can construct a non singular Universe with an inflationary epoch.
يهدف هذا المقال الى دراسة ظاهرة الفيضانات بالحوض النهري لأيت امحمد، الذي ينتمي الى الحوض المائي لأم الربيع. وتبنت هذه الدراسة مقاربة خرائطية تعتمد على نظم المعلومات الجغرافية، تأخذ في الاعتبار مختلف العوامل الطبيعية والبشرية المسؤولة عن نشوء الفيضانات. خلصت هذه الدراسة من جهة إلى أن التضاريس الوعرة والشديدة الانحدار وقوة التساقطات المركزة خلال فصلي الشتاء والربيع والأمطار الرعدية الاستثنائية خلال فصل الصيف ساهمت بشكل كبير في توفير ظروف ملائمة لتكون أحداث فيضية متتالية، نتيجة سرعة وقوة الجريان السطحي المهمة وقصر زمن الاستجابة الهيدرولوجية بالحوض. من جهة أخرى، زاد استقرار الإنسان واستغلاله للمجرى الأكبر وأحيانا للمجرى الاعتيادي لمجرى واد برنات من تفاقم خطر الفيضانات وخلف خسائر فادحة. وتعتبر خرائط الخطر التي تم إنشاؤها في هذا الصدد بالمناطق الأكثر عرضة للفيضانات من التدابير التي تسمح لمختلف الفاعلين المعنيين بالتدخل لمنع الاستقرار بمناطق الخطر ووضع خطة استباقية لتدبير الكوارث الهيدرولوجية والحد من انعكاسات الفيضانات على المجال والمجتمع.
الكلمات المفاتيح: الفيضانات، كارطوغرافية الخطر الفيضي، الحوض النهري ايت امحمد
Дмитрий Александрович Куприянов, Наталья Михайловна Писарчук, Антон Евгеньевич Шатунов
et al.
Представлены результаты изучения отложений нового разреза болота Шкреды на ключевом участке в пределах Национального парка «Себежский». Ключевой участок представляет собой типичные для Себежского Поозерья геосистемы. Реконструированы эволюция растительного покрова и периодичность лесных пожаров Себежского Поозерья, а также факторы, обусловливавшие смены растительного покрова и пожарных режимов в пределах ключевого участка. Аналогичные исследования для изучаемой территории ранее не проводились. В основе реконструкции лежат данные анализа физико-химических свойств болотных отложений (анализ потерь при прокаливании и гумификации, спорово-пыльцевой и антракологический анализ, ботанический анализ торфа). Относительно небольшой размер выбранного для исследования болота обусловлен индикаторной способностью малых болот отражать локальные смены растительного покрова из-за аккумуляции пыльцы и макроскопических частиц с территории радиусом 1,5–2,5 км от края болота. На основании изменений в составе спектров выделено восемь пыльцевых зон, объединенных в три фазы развития растительности. Данные фазы коррелируют с результатами анализа концентрации макроскопических частиц угля, потерь при прокаливании, оптической плотности, а также с результатами кластерного анализа. Выделенные фазы эволюции растительного покрова соотносятся с изменениями активности лесных пожаров. Фаза I отличается преобладанием хвойно-широколиственных лесов с участием березы и частыми лесными пожарами, обусловленными в первую очередь теплыми и сухими климатическими условиями. Фаза II характеризуется распространением хвойно-широколиственных лесов с участием термофильных элементов при минимальном воздействии пирогенного фактора в условиях более влажного климата. Фаза III выделяется господством березово-сосновых лесов и активным развитием процессов заболачивания с участием лесных пожаров. Трансформация растительного покрова в фазе III была вызвана как климатическими причинами, так и антропогенным воздействием, а лесные пожары имели смешанный генезис в условиях начала активного преобразования природной среды человеком.
Natalia Albuquerque, Carine Savalli, Marina Belli
et al.
Capuchin monkeys have rich social relationships and from very young ages they participate in complex interactions with members of their group. Lipsmacking behaviour, which involves at least two individuals in socially mediated interactions, may tell about processes that maintain, accentuate or attenuate emotional exchanges in monkeys. Lipsmacking is a facial expression associated with the establishment and maintenance of affiliative interactions, following under the ‘emotional regulation’ umbrella, which accounts for the ability to manage behavioural responses. We investigated behaviours related to the emitter and to the receiver (infant) of lipsmacking to answer the question of how lipsmacking occurs. In capuchin monkeys, lipsmacking has been previously understood solely as a face-to-face interaction. Our data show that emitters are engaged with infants, looking longer towards their face and seeking eye contact during the display. However, receivers spend most of the time looking away from the emitter and stay in no contact for nearly half of the time. From naturalistic observations of wild infant capuchin monkeys from Brazil we found that lipsmacking is not restricted to mutual gaze, meaning there are other mechanisms in place than previously known. Our results open paths to new insights about the evolution of socio-emotional displays in primates.
We present a 4-dimensional generally covariant gauge theory which leads to the Gauss constraint but lacks both the Hamiltonian and spatial diffeomorphism constraints. The canonical theory therefore resembles Yang-Mills theory without the Hamiltonian. We describe its observables, quantization, and some generalizations.
In this study, we investigate the linear transport of neutral system within the framework of relativistic kinetic theory. Under the relaxation time approximation, we obtain an iterative solution to the relativistic Boltzmann equation in generic stationary spacetime. This solution provides a scheme to study non-equilibrium system order by order. Our calculations are performed in generic hydrodynamic frame, and the results can be reduced to a specific hydrodynamic frame by imposing constraints. As a specific example, we analytically calculated the covariant expressions of the particle flow and the energy momentum tensor up to the first order in relaxation time. Finally and most importantly, we present all 14 kinetic coefficients for a neutral system, which are verified to satisfy the Onsager reciprocal relation in a generic hydrodynamic frame and guarantee a non-negative entropy production in the frame where the first order conservation laws are restored.
Space-based gravitational wave (GW) detection is one of the most anticipated GW detection projects in the next decade, which promises to detect abundant compact binary systems. At present, deep learning methods have not been widely explored for GW waveform generation and extrapolation. To solve the data processing difficulty and the increasing waveform complexity caused by the detector's response and second-generation time-delay interferometry (TDI 2.0), an interpretable pre-trained large model named CBS-GPT (Compact Binary Systems Waveform Generation with Generative Pre-trained Transformer) is proposed. For compact binary system waveforms, three models were trained to predict the waveforms of massive black hole binaries (MBHB), extreme mass-ratio inspirals (EMRIs), and galactic binaries (GB), achieving prediction accuracies of at most 99%, 91%, and 99%, respectively. The CBS-GPT model exhibits notable generalization and interpretability, with its hidden parameters effectively capturing the intricate information of waveforms, even with the complex instrument response and a wide parameter range. Our research demonstrates the potential of large models in the GW realm, opening up new opportunities and guidance for future researches such as complex waveforms generation, gap completion, and deep learning model design for GW science.
O presente artigo, resultado parcial de pesquisa de mestrado em andamento com apoio da FAPESP (Processo nº 2021/00573-7), pretende contribuir com apontamentos acerca das táticas penais tomadas enquanto analisadores das relações de poder em jogo em ocupações de moradia do centro expandido da cidade de São Paulo. O material de análise são trajetórias e experiências de moradores marcadas pela relação com os dispositivos punitivos do Estado (com ênfase na prisão), reunidas através de trabalho de campo etnográfico, em cotejo com outras fontes (processos judiciais, mídia, entrevista).
Abstract Whilst virtual reality (VR) has a long history, recent technological advancements, increased accessibility and affordability have seen its usage become widespread within western consumer society. Despite the relevance of VR to Geography, these more recent developments have escaped scholarly attention. This paper takes a critical perspective on the development of VR and its varied applications, and how emerging theoretical debates within cultural and digital geography can critically attend to the social and cultural implications of VR technologies. The paper begins by considering how VR spaces are imagined and communicated to publics in ways that promote popular understandings of, and desires for, virtual spaces. Next, the paper critically addresses the cultural politics of VR content, particularly drawing attention to the socio‐spatial differences evoked through VR. The paper goes on to argue for the need to consider VR through the concept of interface as a way of critically attending to the broader techno‐socio relations and the embodied spatial encounters they produce. Finally, some methodological implications for thinking with and through VR are outlined.
تعد رکلة الجزاء من أکثر مهارات ضرب الکرة بالقدم أهمية يري الدارس أن رکلة الجزاء هي أسهل وأسرع الطرق لإحراز الأهداف حيث يقف اللاعب في مواجهة مباشرة حارس المرمي دون أي ضغط من دفاع الفريق المنافس مما يتطلب أن يکون لدي اللاعب القائم بالرکلة قدرات خاصة تمکنه من ضبط النفس ومراعاة الدقة التامة في توجيه الکرة للمکان الصحيح داخل المرمي ويهدف البحث الي: - - إلى التعرف على تأثير البرنامج التدريبي باستخدام ثلاثة أساليب مختلفة لإداء رکلات الجزاء للاعبي الدرجة الأولي في کرة القدم. واستخدم البحث المنهج الوصفي والتجريبي. وتکونت عينة البحث من 5 لاعبا وحارسا للمرمي بنادي ليدرز الرياضي . وتمثلت أدوات البحث في المقابلات الشخصية وتصميم استمارة لجمع نتائج التصويب لرکلات الترجيح المقترحة. وتوصلت النتائج الي ان أداء الاسلوب الثاني المتمثل في سرعة خطوات الجري للاعب لرکل الجزاء من المسافة المقطوعة 5ياردة تقريبا وان هذه السرعة تؤدي الي زيادة قوة الکرة وبالتالي سرعة الکرة في الدخول الي المرمي. وقد أدي تأخير تحرک حارس المرمي الي زاوية من الزوايا قبل رکل الکرة مباشرة وخاصة ان حراس المرمي أثناء تنفيذ البرنامج التدريبي ومعرفة أنواع الأساليب والتي تتفق على فکرة واحدة وهي تأخير التصويب حتي تحرک حارس المرمي الي زاوية التصويب الي الزاوية الأخرى. وادي ذلک في الحالات الثلاثة الي الهدار العديد من الفرص لمعرفة الحراس لهذه الفکرة. وأوصي البحث بضرورة استخدام الأسلوب الثاني في تنفيذ رکلات الجزاء الترجيحية سواء في المباريات الرسمية المحلية أو البطولات الدولية. وتطبيق الأسلوب الثاني في تنفيذ الرکلات أثناء الوحدات التدريبية اليومية بتخصيص زمن في نهاية الوحدة أو أثناء التدريب.
<em>Objective</em>: to generalize the method of using integral exercises for the development of the physical qualities of aykidists at the initial training stage.<em> Material</em>: young aikidists, 11-13 years old, took part in the study. They were involved in the youth sports club of the Kherson Regional Aikido Federation. All tests that were used in the study were divided into two groups. Tests to determine overall physical fitness were aimed at the demonstration of speed-strength abilities, agility, strength and flexibility by young athletes. Tests to determine the special physical fitness of young aikidists were aimed at the manifestation of special coordination readiness, speed and strength of the upper shoulder girdle, special endurance and strength of the lower extremities <em>Results</em>: the training method consisted of various complexes of integral exercises, which were used both in the preparatory part of the training, and in the main and final ones. Absolutely for all tests that determine general physical fitness, the level of increase in average results ranges from 5% to 35%. Moreover, the greatest changes were recorded in the indices of the test: bending forward from a sitting position: 35.1%, and the smallest for a long jump from the spot: 4.8%. <em>Conclusions</em>: the correct and rational use of various means and methods for the development of physical qualities allows you to effectively influence the level of physical fitness of young aykidists and makes it possible for them to achieve the highest possible level of skill. In modern aikido, only a rational combination of all sides of preparedness will allow to achieve significant results.<em> </em>A promising direction for further research is the synthesis of the physical and technical training of young akidists using integral exercises.
Sports, Recreation leadership. Administration of recreation services
In this thesis, the connections between thermodynamics and general relativity are explored. We review the concept of gravitationally induced temperature gradients in equilibrium states, first introduced by Richard Tolman. We explore these Tolman-like temperature gradients, understanding their physical origin and whether they can be generated by other forces or not. We then generalize this concept for fluids following generic four-velocities, which are not necessarily generated by Killing vectors, in general stationary space-times. We then move to a more fundamental question: can we still define thermal equilibrium for non-Killing flows? To answer this we review two of the main theories of relativistic non-perfect fluids: Classical Irreversible Thermodynamics and Extended Irreversible Thermodynamics. We also take a tour through the interesting concept of Born-rigid motion, showing some explicit examples of non-Killing rigid flows for Bianchi Type I space-times. These results are important since they show that the Herglotz--Noether theorem cannot be extended for general curved space-times. We then connect the Born-rigid concept with the results obtained by the relativistic fluid's equilibrium conditions and show that the exact thermodynamic equilibrium can only be achieved along a Killing flow. We do, however, introduce some interesting possibilities which are allowed for non-Killing flows. Following, we launch into black hole thermodynamics, specifically studying the trans-Planckian problem for Hawking radiation. We construct a kinematical model consisting of matching two Vaidya spacetimes along a thin shell and show that, as long as the Hawking radiation is emitted only a few Planck lengths (in proper distance) away from the horizon, the trans-Plackian problem can be avoided.
The recent detections of gravitational waves from binary systems of black holes are in remarkable agreement with the predictions of General Relativity. In this pedagogical mini-review, I will go through the physics of the different phases of the evolution of black hole binary systems, providing a qualitative physical interpretation of each one of them. I will also briefly describe how these phases would be modified if gravitation were described by a theory extending or deforming General Relativity, or if the binary components turned out to be more exotic compact objects than black holes.
Daniele Carla da Silva, Maria Cristiane Fernandes da Silva Lunas
This work aimed to give continuity to the historical rescue process of the Dourados Municipal Tourism Council - COMTUR, to raise its main actions between 2004 and 2012, and to make a discussion about its performance and contribution to the development of tourism in the municipality. He also wanted to talk about instances of governance and how the municipal tourism council fits into its actions. The methodology of the work was organized through bibliographical and documentary research, mainly searches in minutes of council meetings, identifying the most important actions in which the council was involved. The study resulted in the identification of the actions carried out by the council and public authorities regarding the development of tourism for the city of Dourados. This work also shows great performance of the Municipality of Dourados and the State University of Mato Grosso do Sul - UEMS, in the activities of the council.
We calculate the most general action for a scalar-tensor model up to quadratic order in derivatives with deformed general covariance and non-minimal coupling. We demonstrate how different choices of the free functions recover specific well known scalar-tensor models. We look at the cosmological dynamics and find the general conditions for either inflation or a big bounce. Using this we present a novel non-minimally coupled scalar model which produces a bounce, and describe how to find similar models.
Migration control at Greece's eastern border is mainly based on the detention of migrants who have crossed the border without authorisation. In the 2000s, unregulated detention places with heterogeneous functions emerged. This article explores how the authorities can control migrants in these places. It consists in particular of a spatio-temporal uncertainty that reinforces the repressive and dissuasive character of liberty deprivation. These uncertainties are not limited to the scale of the place, but are combined with frequent transfers that can occur at any time. By following the forced migrants’ mobilities, this article examines the detention places functions, their multiplication and their network connections.
Tramways have made a remarkable comeback in France since the 1980s. An organization of public transport based on the decentralized administration system set up in the early 1980s has allowed local urban authorities to make their own choices to develop public transport networks in the context of automobile domination. As in many other countries, worries about fossil fuel dependency and demands concerning sustainable urban development appear as strong elements in favour of urban light rail. However, in France, tramways are not just technical solutions for traffic congestion, they have also become a symbol of a cultural mutation in urban development planning. Coupled with a national political push for a more inclusive city in social terms, tramways are the backbone of contemporary urban policies, in a French version of transit-oriented development (TOD), especially for mid-size cities.
The atmospheric features associated with extreme cold events, identified by the temperature drop in the winter, in three regions of southeastern South America are analyzed with reanalysis data from NCEP / NCAR as well as simulations of the coupled ocean-atmosphere HadCM3 and GFDL-CM2.0 models for the present and CMIP3 A2 future scenario. In the present climate, GFDL-CM2.0 represents better the reanalysis fields, being more coherent with the post-frontal high pressure and the 0°C and better the reanalysis fields, being more coherent with the post-frontal high pressure and the 0°C and10°C isotherms. For the future climate, GFDL-CM2.0 projects weakening of temperature anomalies and lower advance of the extreme events of temperature drop in direction to the Equator, while the HadCM3 projection also indicates lower latitudinal range, but in general, higher intensity of these events.
Geography. Anthropology. Recreation, Human ecology. Anthropogeography