2,608 research outputs found
Wavelets: a powerful tool for studying rotation, activity, and pulsation in Kepler and CoRoT stellar light curves
Aims. The wavelet transform has been used as a powerful tool for treating
several problems in astrophysics. In this work, we show that the time-frequency
analysis of stellar light curves using the wavelet transform is a practical
tool for identifying rotation, magnetic activity, and pulsation signatures. We
present the wavelet spectral composition and multiscale variations of the time
series for four classes of stars: targets dominated by magnetic activity, stars
with transiting planets, those with binary transits, and pulsating stars.
Methods. We applied the Morlet wavelet (6th order), which offers high time and
frequency resolution. By applying the wavelet transform to the signal, we
obtain the wavelet local and global power spectra. The first is interpreted as
energy distribution of the signal in time-frequency space, and the second is
obtained by time integration of the local map. Results. Since the wavelet
transform is a useful mathematical tool for nonstationary signals, this
technique applied to Kepler and CoRoT light curves allows us to clearly
identify particular signatures for different phenomena. In particular, patterns
were identified for the temporal evolution of the rotation period and other
periodicity due to active regions affecting these light curves. In addition, a
beat-pattern signature in the local wavelet map of pulsating stars over the
entire time span was also detected.Comment: Accepted for publication on A&
Teaching Philosophy in Manila
In this talk, Fr. Roque J. Ferriols, S.J. shares some reflections from his experiences in teaching philosophy for almost fifty years in what he describes as a “small corner of Manila”. Teaching philosophy, for him, involves creating an atmosphere, an environment which allows students to see things they could not see before--things that the teacher may not even have seen before. That is why a teacher must have the courage to learn from the students and the patience to cultivate a kind of silence enabling them to move from the world of pure ideas to the world of what is really happening. In this world of the real, what is most important cannot be said but lived. Viewing philosophy as a search for the truth, Fr. Ferriols stresses that a person looking for the truth must admit there is a true answer. This answer might be difficult and may take long to find but there is a true answer. In looking for the truth, it is best to use the language of the place where you are philosophizing. For Fr. Ferriols, this would be the language of “the people outside cleaning the streets, driving the jeepneys, driving the buses, going to their work”.(A Plenary Lecture presented during the International Conference on “Teaching Philosophy in Asian Contexts” sponsored by Missio Aachen, Germany on February 19, 2005 held at Ateneo de Manila University, Philippines. This version was edited with the kind assistance of Dr. Leovino Ma. Garcia. The abstract was also prepared by Dr. Garcia.
As alterações climáticas, o uso da terra, e a produção pecuária
Em Agosto de 2019, a publicação do relatório especial sobre o clima e o uso da terra pelo Painel Intergovernamental sobre as Alterações Climáticas (IPCC) coincidiu, por puro acaso, com a publicação de notícias sobre a aceleração das taxas de destruição da Amazónia. Depois de vários anos em que o problema esteve relativamente controlado, as imagens da floresta em chamas e a visão dantesca do céu de São Paulo, escuro em plena tarde, provocaram indignação nacional e internacional, levando a protestos nas ruas e atitudes controversas por parte do Presidente Jair Bolsonaro e do seu Ministro do Meio Ambiente, Ricardo Salles. Ambos foram acusados de enfraquecer as medidas de combate à exploração de madeira, produção pecuária e mineração ilegais, e de desrespeitarem acordos internacionais sobre a proteção da Amazónia.info:eu-repo/semantics/publishedVersio
Pediatric Hand Surgery Training in Nicaragua: A Sustainable Model of Surgical Education in a Resource-Poor Environment.
Recent reports have demonstrated that nearly two-thirds of the world's population do not have access to adequate surgical care, a burden that is borne disproportionately by residents of resource-poor countries. Although the reasons for limited access to surgical care are complex and multi-factorial, among the most substantial barriers is the lack of trained surgical providers. This is particularly true in surgical subspecialties that focus on life-improving, rather than life-saving, treatments, such as pediatric hand and upper extremity surgery, which manages such conditions as congenital malformations, trauma and post-traumatic deformities including burns, and neuromuscular conditions (brachial plexus birth palsy, spinal cord injury, and cerebral palsy). Many models of providing surgical care in resource-limited environments have been described and implemented, but few result in sustainable models of health-care delivery. We present our experience developing a pediatric hand and upper extremity surgery training program in Nicaragua, a resource-limited nation, that grew out of a collaboration of American and Nicaraguan orthopedic surgeons. We compare this experience to that of surgeons undergoing subspecialty training in pediatric upper limb surgery in the US, highlighting the similarities and differences of these training programs. Finally, we assess the results of this training program and identify areas for further growth and development
Mathematical models of bipolar disorder
We use limit cycle oscillators to model bipolar II disorder, which is characterized by alternating hypomanic and depressive episodes and afflicts about 1% of the United States adult population. We consider two non-linear oscillator models of a single bipolar patient. In both frameworks, we begin with an untreated individual and examine the mathematical effects and resulting biological consequences of treatment. We also briefly consider the dynamics of interacting bipolar II individuals using weakly-coupled, weakly-damped harmonic oscillators. We discuss how the proposed models can be used as a framework for refined models that incorporate additional biological data. We conclude with a discussion of possible generalizations of our work, as there are several biologically-motivated extensions that can be readily incorporated into the series of models presented here
βCaMKII regulates bidirectional long-term plasticity in cerebellar Purkinje cells by a CaMKII/PP2B switch mechanism
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise statedPeer reviewe
Multiple conserved regulatory domains promote Fezf2 expression in the developing cerebral cortex.
BackgroundThe genetic programs required for development of the cerebral cortex are under intense investigation. However, non-coding DNA elements that control the expression of developmentally important genes remain poorly defined. Here we investigate the regulation of Fezf2, a transcription factor that is necessary for the generation of deep-layer cortical projection neurons.ResultsUsing a combination of chromatin immunoprecipitation followed by high throughput sequencing (ChIP-seq) we mapped the binding of four deep-layer-enriched transcription factors previously shown to be important for cortical development. Building upon this we characterized the activity of three regulatory regions around the Fezf2 locus at multiple stages throughout corticogenesis. We identified a promoter that was sufficient for expression in the cerebral cortex, and enhancers that drove reporter gene expression in distinct forebrain domains, including progenitor cells and cortical projection neurons.ConclusionsThese results provide insight into the regulatory logic controlling Fezf2 expression and further the understanding of how multiple non-coding regulatory domains can collaborate to control gene expression in vivo
A jazida da Idade do bronze final da Tapada da Ajuda
Em Julho de 1982 foi localizada, no perímetro da Tapada da Ajuda, uma estação pré-histórica, na sequência da abertura de extenso talude de escavação executado no âmbito da construção de um complexo desportivo da Associação de Estudantes do Instituto Superior de Agronomia. Face ao interesse da jazida, dela se deu imediato conhecimento ao Conselho Directivo daquele Instituto, bem como ao Departamento de Arqueologia do Instituto Português do Património Cultural (IPPC). Ao mesmo tempo, promoveu-se a recolha de material à superfície e no corte exposto, em que se baseou o estudo preliminar da jazida. No seguimento deste primeiro trabalho, continuado pela análise dos materiais entretanto recolhidos por técnicos do Departamento de Arqueologia do IPPC, a quem se agradece a sua cedência para estudo, realizaram-se duas campanhas de escavação, em 1983 e 1984, em cujos resultados se baseia este trabalho.info:eu-repo/semantics/publishedVersio
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