26 research outputs found
The internal rotation profile of the B-type star KIC10526294 from frequency inversion of its dipole gravity modes and statistical model comparison
The internal angular momentum distribution of a star is key to determine its
evolution. Fortunately, the stellar internal rotation can be probed through
studies of rotationally-split non-radial oscillation modes. In particular,
detection of non-radial gravity modes (g modes) in massive young stars has
become feasible recently thanks to the Kepler space mission. Our aim is to
derive the internal rotation profile of the Kepler B8V star KIC 10526294
through asteroseismology. We interpret the observed rotational splittings of
its dipole g modes using four different approaches based on the best seismic
models of the star and their rotational kernels. We show that these kernels can
resolve differential rotation the radiative envelope if a smooth rotational
profile is assumed and the observational errors are small. Based on Kepler
data, we find that the rotation rate near the core-envelope boundary is well
constrained to nHz. The seismic data are consistent with rigid
rotation but a profile with counter-rotation within the envelope has a
statistical advantage over constant rotation. Our study should be repeated for
other massive stars with a variety of stellar parameters in order to deduce the
physical conditions that determine the internal rotation profile of young
massive stars, with the aim to improve the input physics of their models.Comment: 52 pages, 32 figures, accepted for publication in The Astrophysical
Journa
Inertial modes of a freely rotating ellipsoidal planet and their relation to nutations
We compute the inertial modes of a freely rotating two-layer planetary model
with an ellipsoidal inviscid fluid core and a perfectly rigid mantle. We
present a method to derive analytical formulae for the frequencies of the Free
Core Nutation (FCN) and Chandler Wobble (CW) which are valid to all orders of
the dynamical flattening of the core and mantle, and we show how the FCN and CW
are the direct generalisation of the purely fluid Spin-Over mode (SO) and of
the Eulerian Wobble (EW) to the case where the mantle can oscillate freely
around a state of steady rotation. Through a numerical computation for an
axisymmetric (oblate spheroidal) planet, we demonstrate that all other inertial
modes of the steadily rotating fluid core are also free modes of the freely
rotating two-layer planet.Comment: 19 pages, 4 figures, accepted for publication in Planetary Science
Journal (AAS
The Solar Activity Monitor Network – SAMNet
The Solar Activity Magnetic Monitor (SAMM) Network (SAMNet) is a future UK-led international network of ground-based solar telescope stations. SAMNet, at its full capacity, will continuously monitor the Sun’s intensity, magnetic, and Doppler velocity fields at multiple heights in the solar atmosphere (from photosphere to upper chromosphere). Each SAMM sentinel will be equipped with a cluster of identical telescopes each with a different magneto-optical filter (MOFs) to take observations in K I, Na D, and Ca I spectral bands. A subset of SAMM stations will have white-light coronagraphs and emission line coronal spectropolarimeters. The objectives of SAMNet are to provide observational data for space weather research and forecast. The goal is to achieve an operationally sufficient lead time of e.g., flare warning of 2–8 h and provide many sought-after continuous synoptic maps (e.g., LoS magnetic and velocity fields, intensity) of the lower solar atmosphere with a spatial resolution limited only by seeing or diffraction limit, and with a cadence of 10 min. The individual SAMM sentinels will be connected to their master HQ hub where data received from all the slave stations will be automatically processed and flare warning issued up to 26 h in advance
Reflexiones desde el Aula de Clases en Arquitectura
Las lĂneas que siguen a continuaciĂłn son el resultado de un ejercicio acadĂ©mico de estudiantes de noveno semestre del Programa de Arquitectura de la Universidad de la Costa, en el marco de la asignatura Electiva en Proyecto de InvestigaciĂłn II dirigida por el profesor Samuel Padilla-Llano, donde se aborda la investigaciĂłn como un proceso de coproducciĂłn del conocimiento a travĂ©s de metodologĂas y estrategias pedagĂłgicas en el aula que permiten al estudiante deconstruir conceptos y elaborar colectivamente posturas y argumentaciĂłn que aporten a la elaboraciĂłn de ejercicios investigativos que decantan en productos de investigaciĂłn y que reflejan en aprendizaje y el dominio de las competencias genĂ©ricas y especĂficas que consolidan su formaciĂłn acadĂ©mica y profesional. La metodologĂa de este ejercicio rápido de escritura está basada en las lecturas previas de fuentes primarias y bibliografĂa estructurada en las temáticas desarrolladas en la asignatura las cuales tienen un enfoque en la relaciĂłn existente entre la arquitectura y los saberes relacionados con la salud y la medicina. Durante una sesiĂłn de clases de 3 horas se realiza un debate para socializar y puesta en comĂşn de las ideas. Posteriormente cada estudiante dedica un tiempo de la misma sesiĂłn a la elaboraciĂłn del escrito bajo los parámetros indicados (ser reflexiones inĂ©ditas, usar citas bibliográficas a partir de las lecturas, tener control del sistema de citaciĂłn APA). Luego se socializa el resultado y se organiza en documento colectivo y se prepara la publicaciĂłn conjunta como resultado del trabajo reflexivo. Esta serie de lecturas realizadas durante el curso plantea la lectura semanal de dos artĂculos. Estos artĂculos que referencian trabajos locales, nacionales e internacionales, abordan elementos que ponen en discusiĂłn las formas de habitar del ser humano y la calidad de vida en los espacios donde trascurre el habitar. Preguntarnos sobre la calidad del hábitat humano y los aspectos que la definen, tambiĂ©n es un acto que los arquitectos desde una disciplina concentrada en el hacer espacios para habitar (la casa, la calle, el barrio, la ciudad, etc.), debemos asumir con vocaciĂłn y conciencia del efecto y la importancia que tiene sobre la vida del ser (o seres) que habitan el espacio. Y desde esa conciencia, el hacer la arquitectura es el arte de pensar, proyectar y configurar formas de habitar en el mudo
Antiinflammatory Therapy with Canakinumab for Atherosclerotic Disease
Background: Experimental and clinical data suggest that reducing inflammation without affecting lipid levels may reduce the risk of cardiovascular disease. Yet, the inflammatory hypothesis of atherothrombosis has remained unproved. Methods: We conducted a randomized, double-blind trial of canakinumab, a therapeutic monoclonal antibody targeting interleukin-1β, involving 10,061 patients with previous myocardial infarction and a high-sensitivity C-reactive protein level of 2 mg or more per liter. The trial compared three doses of canakinumab (50 mg, 150 mg, and 300 mg, administered subcutaneously every 3 months) with placebo. The primary efficacy end point was nonfatal myocardial infarction, nonfatal stroke, or cardiovascular death. RESULTS: At 48 months, the median reduction from baseline in the high-sensitivity C-reactive protein level was 26 percentage points greater in the group that received the 50-mg dose of canakinumab, 37 percentage points greater in the 150-mg group, and 41 percentage points greater in the 300-mg group than in the placebo group. Canakinumab did not reduce lipid levels from baseline. At a median follow-up of 3.7 years, the incidence rate for the primary end point was 4.50 events per 100 person-years in the placebo group, 4.11 events per 100 person-years in the 50-mg group, 3.86 events per 100 person-years in the 150-mg group, and 3.90 events per 100 person-years in the 300-mg group. The hazard ratios as compared with placebo were as follows: in the 50-mg group, 0.93 (95% confidence interval [CI], 0.80 to 1.07; P = 0.30); in the 150-mg group, 0.85 (95% CI, 0.74 to 0.98; P = 0.021); and in the 300-mg group, 0.86 (95% CI, 0.75 to 0.99; P = 0.031). The 150-mg dose, but not the other doses, met the prespecified multiplicity-adjusted threshold for statistical significance for the primary end point and the secondary end point that additionally included hospitalization for unstable angina that led to urgent revascularization (hazard ratio vs. placebo, 0.83; 95% CI, 0.73 to 0.95; P = 0.005). Canakinumab was associated with a higher incidence of fatal infection than was placebo. There was no significant difference in all-cause mortality (hazard ratio for all canakinumab doses vs. placebo, 0.94; 95% CI, 0.83 to 1.06; P = 0.31). Conclusions: Antiinflammatory therapy targeting the interleukin-1β innate immunity pathway with canakinumab at a dose of 150 mg every 3 months led to a significantly lower rate of recurrent cardiovascular events than placebo, independent of lipid-level lowering. (Funded by Novartis; CANTOS ClinicalTrials.gov number, NCT01327846.
Pervasive gaps in Amazonian ecological research
Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4
While the increasing availability of global databases on ecological communities has advanced our knowledge
of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In
the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of
Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus
crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced
environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian
Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by
2050. This means that unless we take immediate action, we will not be able to establish their current status,
much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio
Pervasive gaps in Amazonian ecological research
Biodiversity loss is one of the main challenges of our time, and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space. While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes, vast areas of the tropics remain understudied. In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity, but it remains among the least known forests in America and is often underrepresented in biodiversity databases. To worsen this situation, human-induced modifications may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge, it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost
Pervasive gaps in Amazonian ecological research
Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost