1,639 research outputs found
Ecological genetics of freshwater fish: a short review of the genotype–phenotype connection
Genética ecológica de los peces de agua dulce: una breve revisión de la conexión genotipo–fenotipo
La ecología molecular o la genética ecológica es una aplicación de la genética de poblaciones que durante las dos últimas décadas ha sufrido un proceso de expansión. Sin embargo, en la ecología molecular predominan los estudios sistemáticos y filogeográficos, con relativamente poco énfasis en el análisis de la base genética del proceso de adaptación a diferentes condiciones ecológicas. Esta relación entre genotipo y fenotipo adaptativo es poco evidente, porque las poblaciones son difíciles de cuantificar y los experimentos son logísticamente complicados. Es interesante destacar que en peces de agua dulce estos estudios no son tan poco frecuentes como en otros grupos de vertebrados. En esta revisión, nuestra intención es resumir los pocos casos en los cuales la relación entre ecología y genética de peces continentales está más desarrollada, principalmente entre marcadores genéticos y fenotipos ecológicos.
Palabras clave: Genética ecológica, Ecología molecular, Interacción genotipo–fenotipo, Adaptación, Genética del paisaje, Introducción de especies.Molecular ecology or ecological genetics is an expanding application of population genetics which has flourished in the last two decades but it is dominated by systematic and phylogeographic studies, with relatively little emphasis on the study of the genetic basis of the process of adaptation to different ecological conditions. The relationship between genotype and adaptive phenotypes is weak because populations are often difficult to quantify and experiments are logistically challenging or unfeasible. Interestingly, in freshwater fish, studies to characterize the genetic architecture of adaptive traits are not as rare as in other vertebrate groups. In this review, we summarize the few cases where the relationship between the ecology and genetics of freshwater fish is more developed, namely the relationship between genetic markers and ecological phenotypes.
Key words: Ecological genetics, Molecular ecology, Genotype–phenotype relationship, Adaptation, Landscape genetics, Species introduction.Genética ecológica de los peces de agua dulce: una breve revisión de la conexión genotipo–fenotipo
La ecología molecular o la genética ecológica es una aplicación de la genética de poblaciones que durante las dos últimas décadas ha sufrido un proceso de expansión. Sin embargo, en la ecología molecular predominan los estudios sistemáticos y filogeográficos, con relativamente poco énfasis en el análisis de la base genética del proceso de adaptación a diferentes condiciones ecológicas. Esta relación entre genotipo y fenotipo adaptativo es poco evidente, porque las poblaciones son difíciles de cuantificar y los experimentos son logísticamente complicados. Es interesante destacar que en peces de agua dulce estos estudios no son tan poco frecuentes como en otros grupos de vertebrados. En esta revisión, nuestra intención es resumir los pocos casos en los cuales la relación entre ecología y genética de peces continentales está más desarrollada, principalmente entre marcadores genéticos y fenotipos ecológicos.
Palabras clave: Genética ecológica, Ecología molecular, Interacción genotipo–fenotipo, Adaptación, Genética del paisaje, Introducción de especies
Thermal diagnostic of the Optical Window on board LISA Pathfinder
Vacuum conditions inside the LTP Gravitational Reference Sensor must comply
with rather demanding requirements. The Optical Window (OW) is an interface
which seals the vacuum enclosure and, at the same time, lets the laser beam go
through for interferometric Metrology with the test masses. The OW is a
plane-parallel plate clamped in a Titanium flange, and is considerably
sensitive to thermal and stress fluctuations. It is critical for the required
precision measurements, hence its temperature will be carefully monitored in
flight. This paper reports on the results of a series of OW characterisation
laboratory runs, intended to study its response to selected thermal signals, as
well as their fit to numerical models, and the meaning of the latter. We find
that a single pole ARMA transfer function provides a consistent approximation
to the OW response to thermal excitations, and derive a relationship with the
physical processes taking place in the OW. We also show how system noise
reduction can be accomplished by means of that transfer function.Comment: 20 pages, 14 figures; accepted for publication in Class. Quantum Gra
Integral Field Spectroscopy based H\alpha\ sizes of local Luminous and Ultraluminous Infrared Galaxies. A Direct Comparison with high-z Massive Star Forming Galaxies
Aims. We study the analogy between local U/LIRGs and high-z massive SFGs by
comparing basic H{\alpha} structural characteristics, such as size, and
luminosity (and SFR) surface density, in an homogeneous way (i.e. same tracer
and size definition, similar physical scales). Methods. We use Integral Field
Spectroscopy based H{\alpha} emission maps for a representative sample of 54
local U/LIRGs (66 galaxies). From this initial sample we select 26 objects with
H{\alpha} luminosities (L(H{\alpha})) similar to those of massive (i.e. M\ast
\sim 10^10 M\odot or larger) SFGs at z \sim 2, and observed on similar physical
scales. Results. The sizes of the H{\alpha} emitting region in the sample of
local U/LIRGs span a large range, with r1/2(H{\alpha}) from 0.2 to 7 kpc.
However, about 2/3 of local U/LIRGs with Lir > 10^11.4 L\odot have compact
H{\alpha} emission (i.e. r1/2 < 2 kpc). The comparison sample of local U/LIRGs
also shows a higher fraction (59%) of objects with compact H{\alpha} emission
than the high-z sample (25%). This gives further support to the idea that for
this luminosity range the size of the star forming region is a distinctive
factor between local and distant galaxies of similar SF rates. However, when
using H{\alpha} as a tracer for both local and high-z samples, the differences
are smaller than the ones recently reported using a variety of other tracers.
Despite of the higher fraction of galaxies with compact H{\alpha} emission, a
sizable group (\sim 1/3) of local U/LIRGs are large (i.e. r1/2 > 2 kpc). These
are systems showing pre-coalescence merger activity and they are
indistinguishable from the massive high-z SFGs galaxies in terms of their
H{\alpha} sizes, and luminosity and SFR surface densities.Comment: Accepted for publication in A&A. (!5 pages, 7 figures, 2 tables
Demographic limitation processes
20 páginas, 2 figuras, 1 tabla, 3 cuadros.-- Editor: Valladares, F.[ES]: Procesos de limitación demográfica. Este capítulo ofrece una revisión de los factores que afectan a la regeneración natural de la vegetación, considerando la serie de etapas demográficas que determinan la dinámica demográfica de una pobla- ción. Son muy escasos los estudios disponibles que analizan toda la serie de eventos concatenados entre la producción de flores y frutos y el establecimiento exitoso de una planta adulta reproductiva. También son escasos los trabajos que permiten establecer los efectos aplazados que tienen las interacciones con animales a lo largo del ciclo de regeneración. La aproximación que proponemos cuantifica las pérdidas de propágulos en cada etapa demográfica e identifica “cuellos de botella” del reclutamiento que pue- den colapsar la regeneración natural de una especie. Revisamos una serie de casos de estudio que ilustran diversos procesos de limitación demográfica. El uso de técnicas explícitamente demográficas es fundamental para comprender la evolución de las especies forestales Mediterráneas y para diseñar actuaciones de preservación de sus poblaciones y de su extraordinaria diversidad.[EN]: We review the main factors
influencing recruitment limitation in Mediterranean woody species by considering the
sequential stages that determine the demographic cycle. Very few studies examine the
whole set of demographic stages, from flower production to the successful establishment
of adult reproductive plants, and their influence on recruitment. There are also few studies
exploring the delayed effects of animal interactions throughout the regeneration
cycle, but the information on stage-specific effects is more detailed. We propose an
approach that quantifies the propagule losses at each sequential demographic stage and
identifies demographic bottlenecks that might collapse population growth. We review a
series of case studies illustrating different limitation processes. The use of explicit demographic
techniques is central to understand the evolution of Mediterranean woody species
and to design sound, ecologically-based, conservation plans to preserve their extraordinary
diversity.Juan Arroyo agradece la financiación otorgada a los proyectos 4474-91
(National Geographic Society), PB 91-0894, PB95-0551, 1FD97-0743-CO3-03, PB98-1144,
BOS200307924-CO2-01 (MECD, MCyT). Los trabajos de Pedro Jordano han sido financiados con proyectos MECD y MCyT (1FD97-0743-CO3-01, PB
96-0857, BOS2000-1366-C02-01 y REN2003-00273), así como la Junta de Andalucía (PAI).
Juan Luis García-Castaño estuvo financiado durante su período pre-doctoral con una beca
FPU, AP96-27318040. El trabajo de Fernando Pulido ha sido parcialmente financiado por una
beca FPI de la Junta de Extremadura y los proyectos regional IPR-0A050 y estatal BOS2002-
12222-E del Ministerio de Ciencia y Tecnología. Los trabajos de Patricio García-Fayos han
sido financiados con proyectos MCyT (1FD97-0551), de la Generalitat Valenciana (02-046)
y de la Institució Alfons el Magnánim (02-046)Peer reviewe
Extracting H flux from photometric data in the J-PLUS survey
We present the main steps that will be taken to extract H emission
flux from Javalambre Photometric Local Universe Survey (J-PLUS) photometric
data. For galaxies with , the H+[NII] emission is
covered by the J-PLUS narrow-band filter . We explore three different
methods to extract the H + [NII] flux from J-PLUS photometric data: a
combination of a broad-band and a narrow-band filter ( and ), two
broad-band and a narrow-band one (, and ), and a SED-fitting
based method using 8 photometric points. To test these methodologies, we
simulated J-PLUS data from a sample of 7511 SDSS spectra with measured
H flux. Based on the same sample, we derive two empirical relations to
correct the derived H+[NII] flux from dust extinction and [NII]
contamination. We find that the only unbiased method is the SED fitting based
one. The combination of two filters underestimates the measurements of the
H + [NII] flux by a 28%, while the three filters method by a 9%. We
study the error budget of the SED-fitting based method and find that, in
addition to the photometric error, our measurements have a systematic
uncertainty of a 4.3%. Several sources contribute to this uncertainty:
differences between our measurement procedure and the one used to derive the
spectroscopic values, the use of simple stellar populations as templates, and
the intrinsic errors of the spectra, which were not taken into account. Apart
from that, the empirical corrections for dust extinction and [NII]
contamination add an extra uncertainty of 14%. Given the J-PLUS photometric
system, the best methodology to extract H + [NII] flux is the
SED-fitting based one. Using this method, we are able to recover reliable
H fluxes for thousands of nearby galaxies in a robust and homogeneous
way.Comment: 11 pages, 14 figures. Minor changes to match the published versio
Solitons and instantons in vacuum stability
We investigate the instanton solutions and soliton-like bubbles in vacuum dynamics. We show that the results of recent CERN experiments lead to the fact that our vacuum is safe. We present a new mechanism, where the space-time dimension plays an important role, that explains why our Universe is stable. We provide new evidence that supports a process for the origin of Matter-Antimatter Asymmetry recently introduced by other scientists. We examine confinement in the context of escape problems. We discuss multiverse, string theory landscape, and extra-dimensions using our framework. We use our solutions to introduce some hypotheses about Dark Matter and Dark Energy
Spread of the invasive alga Caulerpa racemosa var. cylindracea (Caulerpales, Chlorophyta) along the Mediterranean Coast of the Murcia region (SE Spain)
The aim of this paper was to document the appearance and spread of the green alga Caulerpa racemosa along the coast of Murcia in south–eastern Spain. It was found for the first time in the area in 2005 and over the next two years the number of new sightings increased almost exponentially. In the period 2005–2007 the total surface area colonised by the alga in the region was estimated to be at least 265 ha. Benthic assemblages colonised by the alga were rocky bottoms with photophilic algae, dead P. oceanica rhizomes, infralittoral and circalittoral soft bottoms and maerl beds. No penetration of the alga was observed in P. oceanica meadows, except in one locality. Biometric analysis indicated high vegetative development in the established colonies in comparison to those described in other Mediterranean areas. Rapid spreading dynamics observed in the Murcia region is a potential threat for native benthic communities.
Key words: Biological invasions, Caulerpa racemosa var. cylindracea, Colonised surface area, Distribution, Mediterranean Sea, Spain.En el presente trabajo se documenta la aparición y dispersión del alga verde Caulerpa racemosa a lo largo de la costa de Murcia, región situada en el sureste español. El alga fue detectada por primera vez en el año 2005 y durante los dos años consecutivos se observó un crecimiento casi exponencial en el número de áreas colonizadas. La superficie total colonizada por el alga en Murcia durante el periodo 2005–2007 ha sido estimada en 265 ha., siendo las comunidades bentónicas afectadas algas fotófilas sobre sustrato rocoso, "mata muerta" de P. oceanica, fondos blandos infralitorales y circalitorales y fondos con comunidades de maërl. La presencia del alga dentro de praderas de P. oceanica solamente fue detectada en una localidad. Los estudios biométricos realizados muestran un elevado desarrollo vegetativo de las poblaciones de C. racemosa en Murcia en comparación con colonias de otras áreas del Mediterráneo, siendo esta rápida dinámica de expansión una amenaza potencial para las comunidades bentonicas nativas.
Palabras clave: Invasiones biológicas, Caulerpa racemosa var. cylindracea, Superficie colonizada, Mar
Mediterraneo, España.The aim of this paper was to document the appearance and spread of the green alga Caulerpa racemosa along the coast of Murcia in south–eastern Spain. It was found for the first time in the area in 2005 and over the next two years the number of new sightings increased almost exponentially. In the period 2005–2007 the total surface area colonised by the alga in the region was estimated to be at least 265 ha. Benthic assemblages colonised by the alga were rocky bottoms with photophilic algae, dead P. oceanica rhizomes, infralittoral and circalittoral soft bottoms and maerl beds. No penetration of the alga was observed in P. oceanica meadows, except in one locality. Biometric analysis indicated high vegetative development in the established colonies in comparison to those described in other Mediterranean areas. Rapid spreading dynamics observed in the Murcia region is a potential threat for native benthic communities.
Key words: Biological invasions, Caulerpa racemosa var. cylindracea, Colonised surface area, Distribution, Mediterranean Sea, Spain
Tuberculosis en ovino: epidemiología, patología y evaluación de técnicas diagnósticas
5 páginas, 2 tablas, 1 figura.--Trabajo presentado al: XL Congreso Nacional y el XVI Congreso Internacional de la Sociedad Española de Ovinotecnia y Caprinotecnia. (Castellón de la Plana, España, 16-18 septiembre 2015).Peer Reviewe
Frailty is associated with objectively assessed sedentary behaviour patterns in older adults: Evidence from the Toledo Study for Healthy Aging (TSHA)
Objective: The aim of this study was to examine the association of sedentary behaviour patterns with frailty in older people. Setting: Clinical setting. Design: Cross-sectional, observational study. Participants and measurements: A triaxial accelerometer was used in a subsample from the Toledo Study for Healthy Aging (519 participants, 67–97 years) to assess several sedentary behaviour patterns including sedentary time per day, the number and duration (min) of breaks in sedentary time per day, and the proportion of the day spent in sedentary bouts of 10 minutes or more. Frailty was assessed using the Frailty Trait Scale (FTS). Regression analysis was used to ascertain the associations between sedentary behaviour patterns and frailty. Results: Sedentary time per day and the proportion of the day spent in sedentary bouts of 10 minutes or more, were positively associated with frailty in the study sample. Conversely, the time spent in breaks in sedentary time was negatively associated with frailty. Conclusion: In summary, breaking up sedentary time and time spent in sedentary behaviour are associated with frailty in older people
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