1,000 research outputs found
El águila y el dragón: la batalla del nuevo milenio
Irak, Estados Unidos e Inglaterra han estado en el ojo del huracán debido a la incursión bélica que estos últimos dos realizaron en el 2003 para derrocar al régimen iraquí a pesar de la oposición de muchos países en el Consejo de Seguridad de la ONU
Shifting cultivation and hunting across the savanna-forest mosaic in the Gran Sabana, Venezuela: Facing changes
Background. Human encroachment and overexploitation of natural resources in the Neotropics is constantly increasing. Indigenous communities all across the Amazon, are trapped between a population rise and a hot debate about the sustainability of hunting rates. The Garden Hunting hypothesis states that shifting cultivation schemes (conucos) used by Amazon indigenous communities may generate favorable conditions, increasing abundance of small and medium wildlife species close to the `gardens' providing game for indigenous hunters. Methods. Here, we combined camera trap surveys and spatially explicit interview dataset on Pemón indigenous hunting scope and occurrence in a mosaic of savanna and forest in the Gran Sabana, Venezuela to evaluate to what extent the wildlife resource use corresponds to Garden Hunting hypothesis. We applied the Royle_Nichols model and binomial regression in order to: (1) assess whether abundance of small and medium wildlife species is higher close to conucos and (2) evaluate whether hunters select hunting localities based on accessibility to wildlife resources (closeness to conuco) more than wildlife abundance. Results. We find mixed evidence supporting the Garden Hunting hypothesis predictions. Abundance of small and medium species was high close to conucos but the pattern was not statistically significant for most of them. Pemón seem to hunt in locations dominated by forest, where species abundance was predicted to be higher, than in close vicinity to conucos. Hunting scope was focused on the most abundant species located close to the conuco (Cuniculus paca), but also in less abundant and unavailable species (Crax alector, Tapirus terrestris and Odocoileus virginianus). Conclusions. Our research provided the first attempt of a systematic sampling survey in the Gran Sabana, generating a quantitative dataset that not only describes the current pattern of wildlife abundance, but sets the base-line to monitor temporal and spatial change in this region of highland Amazon. We discuss the applicability of the estimates generated as a baseline as well as, environmental challenges imposed by economic, social and cultural changes such as mining encroachment for wildlife management. Subjects Anthropology, Biodiversity, Conservation Biology, Ecology, Natural Resource Management
Constructions of the soluble potentials for the non-relativistic quantum system by means of the Heun functions
The Schr\"{o}dinger equation where
is rewritten as a more popular form of a second order
differential equation through taking a similarity transformation
with . The Schr\"{o}dinger invariant
can be calculated directly by the Schwarzian derivative and the
invariant of the differential equation . We
find an important relation for moving particle as and thus
explain the reason why the Schr\"{o}dinger invariant keeps constant.
As an illustration, we take the typical Heun differential equation as an object
to construct a class of soluble potentials and generalize the previous results
through choosing different as before. We get a more general
solution through integrating
directly and it includes all
possibilities for those parameters. Some particular cases are discussed in
detail.Comment: 11 page
Use of "ChemSensor" as an early discrimination tool of Iberian pig semen according to their freezability
Para favorecer el uso de dosis de inseminación de semen de porcino congelado-descongelado a nivel comercial, sería interesante conocer de antemano si el semen de verraco congelará bien o mal. El objetivo de este estudio fue evaluar el 'ChemSensor' (cromatógrafo de gases-masas unido a un software de análisis quimiométrico) como herramienta precoz de discriminación entre eyaculados según su congelabilidad. Para ello se utilizaron 33 eyaculados de verracos de raza Ibérica de los cuales se cogió una alícuota de 1 ml de semen y se analizó con el 'ChemSensor', el resto del eyaculado fue congelado-descongelado usando un protocolo estandarizado, para determinar su congelabilidad (buenos y malos congeladores) en función del porcentaje de espermatozoides con la membrana plasmática intacta y el porcentaje de espermatozoides móviles totales post-descongelación. Para el análisis con el 'ChemSensor', las muestras se volatilizaron e ionizaron descomponiéndolas en diferentes iones con un tamaño determinado, que se usaron como variables de discriminación, para separar los eyaculados en función de su congelabilidad. El 'ChemSensor' fue capaz de discriminar todos los eyaculados de los buenos congeladores; y dentro del grupo de los malos congeladores solamente una muestra fue clasificada erróneamente. Debido al reducido número de muestras, la distancia obtenida entre grupos (2,62), aunque no muy elevada, podría considerarse como significativa, aunque sería necesario un mayor número de muestras para poder crear un modelo matemático más robusto. En conclusión, el 'ChemSensor' es una posible herramienta adecuada para la discriminación precoz de eyaculados de cerdo Ibérico en función de su congelabilidad
Acculturation Influences Postpartum Eating, Activity, and Weight Retention in Low-Income Hispanic Women
Background: Low-income Hispanic women experience elevated rates of high postpartum weight retention (PPWR), which is an independent risk factor for lifetime obesity. Sociocultural factors might play an important role among Hispanic women; however, very few studies have examined this association. Objective: The purpose of our study was to examine the associations between acculturation and maternal diet, physical activity, and PPWR. Design: This is a cross-sectional study of baseline data from 282 Hispanic women participating in the FitMoms/Mamás Activas study, a randomized controlled trial examining the impact of primarily an internet-based weight control program, in reducing PPWR among low-income women. We performed multivariable linear regression to examine the association of acculturation with diet quality, physical activity, and PPWR at study entry. Results: A total of 213 (76%) women had acculturation scores reflecting Mexican orientation or bicultural orientation, whereas 69 (24%) had scores that represented assimilation to Anglo culture. Women who were more acculturated had lower intakes of fruits and vegetables, lower HEI scores, and lower physical activity levels than women who were less acculturated (p < 0.05). We found an association between acculturation and PPWR in that for every 1-unit increase in acculturation score, PPWR increased, on average, by 0.80 kg. Conclusion: Higher acculturation was associated with poorer diet and physical activity behaviors and greater PPWR
Charge separation relative to the reaction plane in Pb-Pb collisions at TeV
Measurements of charge dependent azimuthal correlations with the ALICE
detector at the LHC are reported for Pb-Pb collisions at TeV. Two- and three-particle charge-dependent azimuthal correlations in
the pseudo-rapidity range are presented as a function of the
collision centrality, particle separation in pseudo-rapidity, and transverse
momentum. A clear signal compatible with a charge-dependent separation relative
to the reaction plane is observed, which shows little or no collision energy
dependence when compared to measurements at RHIC energies. This provides a new
insight for understanding the nature of the charge dependent azimuthal
correlations observed at RHIC and LHC energies.Comment: 12 pages, 3 captioned figures, authors from page 2 to 6, published
version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/286
Multiplicity dependence of jet-like two-particle correlations in p-Pb collisions at = 5.02 TeV
Two-particle angular correlations between unidentified charged trigger and
associated particles are measured by the ALICE detector in p-Pb collisions at a
nucleon-nucleon centre-of-mass energy of 5.02 TeV. The transverse-momentum
range 0.7 5.0 GeV/ is examined,
to include correlations induced by jets originating from low
momen\-tum-transfer scatterings (minijets). The correlations expressed as
associated yield per trigger particle are obtained in the pseudorapidity range
. The near-side long-range pseudorapidity correlations observed in
high-multiplicity p-Pb collisions are subtracted from both near-side
short-range and away-side correlations in order to remove the non-jet-like
components. The yields in the jet-like peaks are found to be invariant with
event multiplicity with the exception of events with low multiplicity. This
invariance is consistent with the particles being produced via the incoherent
fragmentation of multiple parton--parton scatterings, while the yield related
to the previously observed ridge structures is not jet-related. The number of
uncorrelated sources of particle production is found to increase linearly with
multiplicity, suggesting no saturation of the number of multi-parton
interactions even in the highest multiplicity p-Pb collisions. Further, the
number scales in the intermediate multiplicity region with the number of binary
nucleon-nucleon collisions estimated with a Glauber Monte-Carlo simulation.Comment: 23 pages, 6 captioned figures, 1 table, authors from page 17,
published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/161
A note on comonotonicity and positivity of the control components of decoupled quadratic FBSDE
In this small note we are concerned with the solution of Forward-Backward
Stochastic Differential Equations (FBSDE) with drivers that grow quadratically
in the control component (quadratic growth FBSDE or qgFBSDE). The main theorem
is a comparison result that allows comparing componentwise the signs of the
control processes of two different qgFBSDE. As a byproduct one obtains
conditions that allow establishing the positivity of the control process.Comment: accepted for publicatio
Multi-particle azimuthal correlations in p-Pb and Pb-Pb collisions at the CERN Large Hadron Collider
Measurements of multi-particle azimuthal correlations (cumulants) for charged
particles in p-Pb and Pb-Pb collisions are presented. They help address the
question of whether there is evidence for global, flow-like, azimuthal
correlations in the p-Pb system. Comparisons are made to measurements from the
larger Pb-Pb system, where such evidence is established. In particular, the
second harmonic two-particle cumulants are found to decrease with multiplicity,
characteristic of a dominance of few-particle correlations in p-Pb collisions.
However, when a gap is placed to suppress such correlations,
the two-particle cumulants begin to rise at high-multiplicity, indicating the
presence of global azimuthal correlations. The Pb-Pb values are higher than the
p-Pb values at similar multiplicities. In both systems, the second harmonic
four-particle cumulants exhibit a transition from positive to negative values
when the multiplicity increases. The negative values allow for a measurement of
to be made, which is found to be higher in Pb-Pb collisions at
similar multiplicities. The second harmonic six-particle cumulants are also
found to be higher in Pb-Pb collisions. In Pb-Pb collisions, we generally find
which is indicative of a Bessel-Gaussian
function for the distribution. For very high-multiplicity Pb-Pb
collisions, we observe that the four- and six-particle cumulants become
consistent with 0. Finally, third harmonic two-particle cumulants in p-Pb and
Pb-Pb are measured. These are found to be similar for overlapping
multiplicities, when a gap is placed.Comment: 25 pages, 11 captioned figures, 3 tables, authors from page 20,
published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/87
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