310 research outputs found
Lepidoptera of North America 6. Butterflies of Oregon their taxonomy, distribution, and biology
March 15, 2005
Dynamical laws of superenergy in General Relativity
The Bel and Bel-Robinson tensors were introduced nearly fifty years ago in an
attempt to generalize to gravitation the energy-momentum tensor of
electromagnetism. This generalization was successful from the mathematical
point of view because these tensors share mathematical properties which are
remarkably similar to those of the energy-momentum tensor of electromagnetism.
However, the physical role of these tensors in General Relativity has remained
obscure and no interpretation has achieved wide acceptance. In principle, they
cannot represent {\em energy} and the term {\em superenergy} has been coined
for the hypothetical physical magnitude lying behind them. In this work we try
to shed light on the true physical meaning of {\em superenergy} by following
the same procedure which enables us to give an interpretation of the
electromagnetic energy. This procedure consists in performing an orthogonal
splitting of the Bel and Bel-Robinson tensors and analysing the different parts
resulting from the splitting. In the electromagnetic case such splitting gives
rise to the electromagnetic {\em energy density}, the Poynting vector and the
electromagnetic stress tensor, each of them having a precise physical
interpretation which is deduced from the {\em dynamical laws} of
electromagnetism (Poynting theorem). The full orthogonal splitting of the Bel
and Bel-Robinson tensors is more complex but, as expected, similarities with
electromagnetism are present. Also the covariant divergence of the Bel tensor
is analogous to the covariant divergence of the electromagnetic energy-momentum
tensor and the orthogonal splitting of the former is found. The ensuing {\em
equations} are to the superenergy what the Poynting theorem is to
electromagnetism. See paper for full abstract.Comment: 27 pages, no figures. Typos corrected, section 9 suppressed and more
acknowledgments added. To appear in Classical and Quantum Gravit
Track analysis beyond panbiogeography
ABSTRACT Aim Panbiogeography, as originally formulated by L eon Croizat, assumed that vicariance and range expansion are the only biogeographical processes needed to explain general biotic distributions. This was in opposition to the prevailing paradigm at the time, known as dispersalism, which postulates that organisms evolve in 'centres of origin' from pre-existing species and then randomly cross barriers to occupy new areas, where they adapt and evolve into new species. The panbiogeographic approach is implemented through track analysis, which consists of three basic steps: constructing individual tracks for two or more different taxa, obtaining generalized tracks where two or more different individual tracks coincide, and identifying nodes in the areas where two or more generalized tracks intersect. In this synthesis I discuss some criticisms that have been directed at panbiogeography and track analysis. Location Global. Methods I evaluated the papers with track analyses that have been published in the last few decades and the critiques provided by several authors. Results Most of the critiques have been directed at the original panbiogeographic approach, with its complete or almost complete reliance on vicariance explanations. Track analyses published in the 1980s and 1990s usually applied a strict vicariance explanation; however, most of the analyses published in the last 10 years or so consider both vicariance and dispersal to explain the observed patterns. Main conclusions Although Croizat's metaphor 'Earth and life evolve together' may be a useful guide to understanding broad, general patterns, the relationships between Earth history and life are more complex because biotic history is reticulate. To reduce our explanations exclusively to vicariance or dispersal is misguided. We should integrate both processes into a dispersalvicariance model that allows us to understand the evolution of biotic distributions, incorporating the dating of the lineages and the identification of the cenocrons (sets of taxa that share the same biogeographical history) that coexist within biotas. In the framework of this model, panbiogeographic track analysis is a useful method for identifying biotas, and may constitute the first step of an evolutionary biogeographical analysis
A survey on Anthozoa and its habitats along the Northwest African coast and some islands: new records, descriptions of new taxa and biogeographical, ecological and taxonomical comments. Part I
Varias especies de Actiniarios y Escleractinias han sido recolectadas y estudiadas a lo largo de la costa noroeste africana y algunos de sus archipiélagos. Esta es la primera parte de un artículo más extenso que está centrado en Marruecos y Cabo Verde pero que también incluye información de otras zonas geográficas (Islas Canarias, Madeira, Gabón y Mauritania). La segunda parte incluirá bastante material del Golfo de Guinea. Cuatro nuevas especies y un nuevo género son descritos además de cinco nuevos registros de especies para la región estudiada. Bellactis caeruleus, Tubastrea caboverdiana, Thalamophyllia wirtzi y Africana wirtzi son las cuatro especies y el nuevo género descrito para la ciencia. Se han completado algunas descripciones de especies que de una forma y otra no estaban bien estudiadas.Several species of Actiniaria and Scleractinia have been searched and collected along the Western African coast and some of its archipelagos. This paper constitutes the first part of an extensive paper and it is focused on Morocco and Cape Verde, although some material and images from other spots (Canary Islands, Madeira, Gabon or even Mauritania) are included. The second part will also include some material from Gulf of Guinea. Four new species and a new genus are described, and five new records are also included in the paper. Bellactis caeruleus, Tubastrea caboverdiana, Thalamophyllia wirtzi and Africana wirtzi are the four new species and the new genus described. Some species, due to previous lack of good descriptions, are presented more deeply from the point of view of the descriptive aspect
Pressure effects on the vibrational properties of alpha-Bi2O3: an experimental and theoretical study
We report an experimental and theoretical high-pressure study of the vibrational properties of synthetic monoclinic bismuth oxide (alpha-Bi2O3), also known as mineral bismite. The comparison of Raman scattering measurements and theoretical lattice-dynamics ab initio calculations is key to understanding the complex vibrational properties of bismite. On one hand, calculations help in the symmetry assignment of phonons and to discover the phonon interactions taking place in this low-symmetry compound, which shows considerable phonon anticrossings; and, on the other hand, measurements help to validate the accuracy of first-principles calculations relating to this compound. We have also studied the pressure-induced amorphization (PIA) of synthetic bismite occurring around 20 GPa and showed that it is reversible below 25 GPa. Furthermore, a partial temperature-induced recrystallization (TIR) of the amorphous sample can be observed above 20 GPa upon heating to 200 C, thus evidencing that PIA at room temperature occurs because of the inability of the a phase to undergo a phase transition to a high-pressure phase. Raman scattering measurements of the TIR sample at room temperature during pressure release have been performed. The interpretation of these results in the light of ab initio calculations of the candidate phases at high pressures has allowed us to tentatively attribute the TIR phase to the recently found high-pressure hexagonal HPC phase and to discuss its lattice dynamics.This work has been supported by Brazilian Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) under project 201050/2012-9, by Ministerio de Ciencia e Innovacion of Spain (MICINN) under the National Program of Materials (MAT2010-21270-C04-03/04) and the Consolider-Ingenio 2010 Program (MALTA CSD2007-0045) and by Generalitat Valenciana through projects GVA-ACOMP-2013-012 and Prometeo 2009/053.Pereira, ALJ.; Gomis, O.; Sans, JA.; Pellicer-Porres, J.; Manjón Herrera, FJ.; Beltran, A.; Rodríguez-Hernández, P.... (2014). Pressure effects on the vibrational properties of alpha-Bi2O3: an experimental and theoretical study. Journal of Physics: Condensed Matter. 26(22):225401-1-225401-15. https://doi.org/10.1088/0953-8984/26/22/225401S225401-1225401-15262
Incidencia de eventos adversos asociados a dispositivosmédicos en una institución de salud en Colombia
Este artículo presenta los resultados de un estudio retrospectivo de eventos adversos asociados a dispositivos médicos (EADMS), presentados en el período de enero a junio de 2010 en el servicio de Cirugía de una institución prestadora de saludo (IPS) en Colombia.This paper presents the results of a retrospective study of adverse events associated with medical devices (AEAMDS), presented during the period of January through June of 2010 in the Surgery Department of a healthcare institution in Colombia
Early-life fecal microbiome and metabolome dynamics in response to an intervention with infant formula containing specific prebiotics and postbiotics
This study examined fecal metabolome dynamics to gain greater functional insights into the interactions between nutrition and the activity of the developing gut microbiota in healthy term-born infants. The fecal samples used here originate from a randomized, controlled, double-blind clinical study that assessed the efficacy of infant formula with prebiotics and postbiotics (experimental arm) compared with a standard infant formula (control arm). A group of exclusively breast-fed term infants was used as a reference arm. First, conventional targeted physiological and microbial measurements were performed, which showed differences in fecal Bifidobacterium levels and corresponding activity (e.g., lactate levels). Next, the overall fecal microbiota composition was determined by 16S rRNA gene amplicon sequencing. The microbiota composition profiles showed several bacterial groups in the experimental arm to be significantly different from the control arm and mostly closer to the levels observed in the reference arm. Finally, we applied an untargeted UPLC-MS/MS approach to examine changes in the fecal metabolome. Fecal metabolome profiles showed the most distinct separation, up to 404 significantly different metabolites, between the study arms. Our data reveal that infant formula with specific prebiotics and postbiotics may trigger responses in the intestinal microbiota composition that brings the ensuing fecal metabolite profile of formula-fed infants closer toward those observed in breast-fed infants. Furthermore, our results demonstrate a clear need for establishing an infant gut metabolome reference database to translate these metabolite profile dynamics into functional and physiologically relevant responses. NEW & NOTEWORTHY Untargeted metabolomics techniques can provide a ???snapshot??? of an ecosystem in response to environmental stimuli, such as nutritional interventions. Our analyses of fecal samples from infants demonstrate the potential of phenotyping by metabolomics while deciphering the complex interactions of early-life nutrition and gut microbiome development
SHINING, A Survey of Far-infrared Lines in Nearby Galaxies. II. Line-deficit Models, AGN Impact, [C II]–SFR Scaling Relations, and Mass–Metallicity Relation in (U)LIRGs
The SHINING survey (Paper I; Herrera-Camus et al. 2018) offers a great opportunity to study the properties of the ionized and neutral media of galaxies from prototypical starbursts and active galactic nuclei (AGN) to heavily obscured objects. Based on Herschel/PACS observations of the main far-infrared (FIR) fine-structure lines, in this paper we analyze the physical mechanisms behind the observed line deficits in galaxies, the apparent offset of luminous infrared galaxies (LIRGs) from the mass-metallicity relation, and the scaling relations between [CII] 158 m line emission and star formation rate (SFR). Based on a toy model and the Cloudy code, we conclude that the increase in the ionization parameter with FIR surface brightness can explain the observed decrease in the line-to-FIR continuum ratio of galaxies. In the case of the [CII] line, the increase in the ionization parameter is accompanied by a reduction in the photoelectric heating efficiency and the inability of the line to track the increase in the FUV radiation field as galaxies become more compact and luminous. In the central kiloparsec regions of AGN galaxies we observe a significant increase in the [OI] 63 m/[CII] line ratio; the AGN impact on the line-to-FIR ratios fades on global scales. Based on extinction-insensitive metallicity measurements of LIRGs we confirm that they lie below the mass-metallicity relation, but the offset is smaller than those reported in studies that use optical-based metal abundances. Finally, we present scaling relations between [CII] emission and SFR in the context of the main-sequence of star-forming galaxies
Adiponectin accounts for gender differences in hepatocellular carcinoma incidence
Hepatocellular carcinoma (HCC) is the sixth most common cancer type and the fourth leading cause of cancer-related death. This cancer appears with higher incidence in men and during obesity; however, the specific mechanisms underlying this correlation are unknown. Adipose tissue, a key organ in metabolic syndrome, shows evident gender disparities in the production of adipokines. Levels of the important adipokine adiponectin decrease in men during puberty, as well as in the obese state. Here, we show that this decrease in adiponectin levels is responsible for the increased liver cancer risk in males. We found that testosterone activates the protein JNK in mouse and human adipocytes. JNK-mediated inhibition of adiponectin secretion increases liver cancer cell proliferation, since adiponectin protects against liver cancer development through the activation of AMP-activated protein kinase (AMPK) and p38α. This study provides insight into adipose tissue to liver crosstalk and its gender relation during cancer development, having the potential to guide strategies for new cancer therapeutics.G. Sabio is an investigator on the Ramón y Cajal Program. E. Manieri is a La Caixa Foundation fellow. L. Herrera-Melle is a fellow of the Ministerio de Educación, Cultura y Deporte (FPU15-05802). This study was funded by the following grants: G. Sabio was funded by the European Research Council (ERC 260464), European Foundation for the Study of Diabetes–Lilly, Ministerio de Ciencia, Innovación y Universidades (MICINN/SAF2016-79126-R), Comunidad de Madrid (B2017/BMD-3733), and BBVA Becas Leonardo a Investigadores y Creadores Culturales (Investigadores-BBVA-2017; IN[17]_BBM_BAS_0066); M. Marcos was funded by Instituto de Salud Carlos III and Federación Española de Enfermedades Raras (PI16/01548); and J.L. Torres was funded by Junta de Castilla y León GRS (1587/A/17). F.J. Cubero is a Ramón y Cajal Researcher (RYC-2014-15242) and a Gilead Liver Research Scholar 2018, and his work is supported by the Ministerio de Economia y Competitividad Retos (SAF2016-78711), Comunidad de Madrid (S2017/BMD-3727), The Alan Morement Memorial Fund Cholangiocarcinoma Charity (2018/117), the European Cooperation in Science and Technology Action (CA17112), and the European Foundation for Alcohol Research (EA14/18). L. Moran is a Comunidad de Madrid fellow (S2017/BMD-3727). The CNIC is supported by the Ministerio de Ciencia, Innovación y Universidades and the Pro CNIC Foundation, and is a Severo Ochoa Center of Excellence (SEV-2015-0505).S
Morphofunctional and Molecular Assessment of Nutritional Status in Head and Neck Cancer Patients Undergoing Systemic Treatment: Role of Inflammasome in Clinical Nutrition
Malnutrition in patients with head and neck cancer is frequent, multifactorial and widely associated with clinical evolution and prognosis. Accurate nutritional assessments allow for early identification of patients at risk of malnutrition in order to start nutritional support and prevent sarcopenia. We aimed to perform a novel morphofunctional nutritional evaluation and explore changes in inflammasome-machinery components in 45 patients with head and neck cancer who are undergoing systemic treatment. To this aim, an epidemiological/clinical/anthropometric/biochemical evaluation was performed. Serum RCP, IL6 and molecular expression of inflammasome-components and inflammatory-associated factors (NOD-like-receptors, inflammasome-activation-components, cytokines and inflammation/apoptosis-related components, cell-cycle and DNA-damage regulators) were evaluated in peripheral-blood mononuclear-cells (PBMCs). Clinical-molecular correlations/associations were analyzed. Coherent and complementary information was obtained in the morphofunctional nutritional assessment of the patients when bioimpedance, anthropometric and ultrasound data were analyzed. These factors were also correlated with different biochemical and molecular parameters, revealing the complementary aspect of the whole evaluation. Serum reactive C protein (RCP) and IL6 were the most reliable parameters for determining patients with decreased standardized phase angle, which is associated with increased mortality in patients with solid malignancies. Several inflammasome-components were dysregulated in patients with malnutrition, decreased phase angle and dependency grade or increased circulating inflammation markers. A molecular fingerprint based on gene-expression of certain inflammasome factors (p27/CCL2/ASC) in PBMCs accurately differentiated patients with and without malnutrition. In conclusion, malnutrition induces a profound alteration in the gene-expression pattern of inflammasome-machinery components in PBMCs. A comprehensive nutritional assessment including novel morphofunctional techniques and molecular markers allows a broad characterization of the nutritional status in cancer patients. Profile of certain inflammasome-components should be further studied as potential targets for nutrition-focused treatment strategies in cancer patients
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