82 research outputs found
Cambios en el regimen pluviométrico y sus efectos sobre la producción agropecuaria en el partido de Puán
La declaración de emergencia climática en vastos sectores de los partidos del suroeste de la provincia de Buenos Aires desde el año 1991, a fin de paliar los efectos de eventos climáticos prolongados; la reducción de la productividad y la pérdida de aptitud agrícola, son los temas principales desarrollados en el presente trabajo. El objetivo del trabajo es el análisis conjunto de las variaciones en el régimen pluviométrico y los cambios en el uso del suelo en el partido de Puán, provincia de Buenos Aires. Se analizaron las características naturales de la región, el cambio de paradigma en la agricultura y las etapas de ocupación del espacio. Los resultados mostraron la existencia de períodos prolongados de sequía y los cambios progresivos en los usos del suelo, tendiendo hacia la agriculturización, implican cuanto menos una situación de alta vulnerabilidad en un sistema de transición como el que se desarrolla en la región. Los planteos y fundamentos de la Ley de Desarrollo del suroeste bonaerense están dirigidos en este sentido, es decir, la revisión de las limitantes para el desarrollo, dentro de las cuales se encuentran aquellas relacionadas con las condiciones climáticas.The weather emergency declaration in vast sectors of matches southwestern province of Buenos Aires since 1991, to mitigate the effects of prolonged weather events, reduced productivity and loss of agricultural potential, are the issues main developed in this work. The objective of this work is the joint analysis of variations in rainfall patterns and changes in land use in the game of Puan, province of Buenos Aires. We analyzed the natural characteristics of the region, the paradigm shift in agriculture and the stages of occupation of space. The results showed the existence of prolonged periods of drought and the progressive changes in land use, tending to agriculturization involve the less a situation of high vulnerability as a transitional system that develops in the region. The proposals and foundations of the Development Act southwest of Buenos Aires are aimed in this direction, ie the review of the limitations for development, among which are those related to weather conditions.Fil: Campo, Alicia María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Geografía y Turismo; ArgentinaFil: Bagnulo, Cecilia Beatriz. Universidad Nacional del Sur. Departamento de Geografía y Turismo; ArgentinaFil: Pacheco, Ramiro. Universidad Nacional del Sur. Departamento de Geografía y Turismo; Argentin
A Novel Mechanism for Gridification of Compiled Java Applications
Exploiting Grids intuitively requires developers to alter their applications, which calls for expertise on Grid programming. Gridification tools address this problem by semi-automatically making user applications to be Grid-aware. However, most of these tools produce monolithic Grid applications in which common tuning mechanisms (e.g. parallelism) are not applicable, and do not reuse existing Grid middleware services. We propose BYG (BYtecode Gridifier), a gridification tool that relies on novel bytecode rewriting techniques to parallelize and easily execute existing applications via Grid middlewares. Experiments performed by using several computing intensive applications on a cluster and a simulated wide-area Grid suggest that our techniques are effective while staying competitive compared to programmatically using such services for gridifying applications
On Supermodular Contracts and Dense Subgraphs
We study the combinatorial contract design problem, introduced and studied by
Dutting et. al. (2021, 2022), in both the single and multi-agent settings.
Prior work has examined the problem when the principal's utility function is
submodular in the actions chosen by the agent(s).
We complement this emerging literature with an examination of the problem
when the principal's utility is supermodular.
In the single-agent setting, we obtain a strongly polynomial time algorithm
for the optimal contract.
This stands in contrast to the NP-hardness of the problem with submodular
principal utility due to Dutting et. al. (2021).
This result has two technical components, the first of which applies beyond
supermodular or submodular utilities.
This result strengthens and simplifies analogous enumeration algorithms from
Dutting et. al. (2021), and applies to any nondecreasing valuation function for
the principal.
Second, we show that supermodular valuations lead to a polynomial number of
breakpoints, analogous to a similar result by Dutting et. al. (2021) for gross
substitutes valuations.
In the multi-agent setting, we obtain a mixed bag of positive and negative
results.
First, we show that it is NP-hard to obtain any finite multiplicative
approximation, or an additive FPTAS.
This stands in contrast to the submodular case, where efficient computation
of approximately optimal contracts was shown by Dutting et. al. (2022).
Second, we derive an additive PTAS for the problem in the instructive special
case of graph-based supermodular valuations, and equal costs.
En-route to this result, we discover an intimate connection between the
multi-agent contract problem and the notorious k-densest subgraph problem.
We build on and combine techniques from the literature on dense subgraph
problems to obtain our additive PTAS.Comment: 31 pages, 2 figure
Processing and mechanical characteristics of magnesium-hydroxyapatite metal matrix biocomposites
Magnesium/hydroxyapatite composites were produced by conventional extrusion and their mechanical behavior studied under uniaxial compression at room temperature. The results evidence the capability of the HA for strengthening the Mg material, lowering its microstructural anisotropy and inhibiting deformation twinning. They also reveal that the ECAP processing is effective for improving the grain structure and reducing the crystallographic texture of these composites, giving rise to a significant enhancement of their yield strength and microhardness although the ultimate compressive stress worsens. The analysis of the strain hardening rate of the flow curves demonstrates that the HA addition and the ECAP processing are also effective in inhibiting non-basal dislocation slip.This work has been supported by the Regional Government of Madrid through the S2013/MIT-2862-MULTIMAT-CHALLENGE Program. R del Campo thanks to the Universidad Carlos III de Madrid for the support
Effect of dietary docosahexaenoic acid supplementation on the participation of vasodilator factors in aorta from orchidectomized rats
Benefits of n-3 polyunsaturated fatty acids (PUFAs) against cardiovascular diseases have
been reported. Vascular tone regulation is largely mediated by endothelial factors whose
release is modulated by sex hormones. Since the incidence of cardiovascular pathologies
has been correlated with decreased levels of sex hormones, the aim of this study was to
analyze whether a diet supplemented with the specific PUFA docosahexaenoic acid (DHA)
could prevent vascular changes induced by an impaired gonadal function. For this purpose,
control and orchidectomized rats were fed with a standard diet supplemented with 5% (w/w)
sunflower oil or with 3% (w/w) sunflower oil plus 2% (w/w) DHA. The lipid profile, the blood
pressure, the production of prostanoids and nitric oxide (NO), and the redox status of biological
samples from control and orchidectomized rats, fed control or DHA-supplemented diet,
were analyzed. The vasodilator response and the contribution of NO, prostanoids and
hyperpolarizing mechanisms were also studied. The results showed that orchidectomy negatively
affected the lipid profile, increased the production of prostanoids and reactive oxygen
species (ROS), and decreased NO production and the antioxidant capacity, as well as
the participation of hyperpolarizing mechanisms in the vasodilator responses. The DHAsupplemented
diet of the orchidectomized rats decreased the release of prostanoids and
ROS, while increasing NO production and the antioxidant capacity, and it also improved the
lipid profile. Additionally, it restored the participation of hyperpolarizing mechanisms by activating
potassium. Since the modifications induced by the DHA-supplemented diet were
observed in the orchidectomized, but not in the healthy group, DHA seems to exert cardioprotective
effects in physiopathological situations in which vascular dysfunction existsThis study was supported by grants to MF
from the Fondo de Investigaciones Sanitarias
(PI1100406), Comunidad de Madrid (S2013/ABI-
2783, “INSPIRA1-CM”), Fondo Europeo de
Desarrollo Regional, and Centro de Estudios América
Latina (Grupo Santander-UAM)
Roles game: a pedagogical strategy for the strengthening of coexistence
La educación ha venido presentando cambios durante
su desarrollo, donde los métodos estratégicos utilizados
por los docentes en el aula de clases son los
elementos fundamentales en el proceso enseñanza
mejorando la convivencia. El presente artículo tiene
como objetivo fomentar el desarrollo del aprendizaje
y mejora de la convivencia de los estudiantes a través
del juego de roles como estrategia pedagógica. Se
realizó un estudio de tipo cualitativo bajo el modelo
de investigación acción, se utilizó una población
conformada por cien (100) estudiantes del Centro
Educativo Caño de Aguas. Durante el proceso investigativo,
se aplicaron técnicas e instrumentos
tales como la observación directa, diarios de campo;
logrando identificar la problemática presente en la
institución. La investigación permitió reconocer la
importancia del juego de roles como herramienta
pedagógica para fortalecer la convivencia dentro de
las aulas de clase, un proceso en el cual el individuo
apropia el conocimiento en sus diferentes dimensiones,
enfocándose en la adquisición de hábitos y
desarrollo de actividades motivadoras.Education has been changing during its development,
where the strategic methods used by teachers
in the classroom are the fundamental elements
in the teaching process, improving coexistence.
The objective of this article is to promote the development
of learning and improve the coexistence
of students through role play as a pedagogical
strategy. A qualitative study was carried out under
the action research model, using a population
made up of one hundred (100) students from the
Caño de Aguas Educational Center. During the
investigative process, techniques and instruments
were applied such as direct observation, field diaries;
managing to identify the problems present
in the institution. The research allowed to recognize
the importance of role play as a pedagogical
tool to strengthen coexistence within classrooms,
a process in which the individual appropriates
knowledge in its different dimensions, focusing
on the acquisition of habits and the development
of motivating activities
The Protist Ribosomal Reference database (PR2): a catalog of unicellular eukaryote Small Sub-Unit rRNA sequences with curated taxonomy
International audienceThe interrogation of genetic markers in environmental meta-barcoding studies is currently seriously hindered by the lack of taxonomically curated reference data sets for the targeted genes. The Protist Ribosomal Reference database (PR2, http://ssu-rrna.org/) provides a unique access to eukaryotic small sub-unit (SSU) ribosomal RNA and DNA sequences, with curated taxonomy. The database mainly consists of nuclear-encoded protistan sequences. However, metazoans, land plants, macrosporic fungi and eukaryotic organelles (mitochondrion, plastid and others) are also included because they are useful for the analysis of high-troughput sequencing data sets. Introns and putative chimeric sequences have been also carefully checked. Taxonomic assignation of sequences consists of eight unique taxonomic fields. In total, 136 866 sequences are nuclear encoded, 45 708 (36 501 mitochondrial and 9657 chloroplastic) are from organelles, the remaining being putative chimeric sequences. The website allows the users to download sequences from the entire and partial databases (including representative sequences after clustering at a given level of similarity). Different web tools also allow searches by sequence similarity. The presence of both rRNA and rDNA sequences, taking into account introns (crucial for eukaryotic sequences), a normalized eight terms ranked-taxonomy and updates of new GenBank releases were made possible by a long-term collaboration between experts in taxonomy and computer scientists
The Protist Ribosomal Reference database (PR2): a catalog of unicellular eukaryote Small Sub-Unit rRNA sequences with curated taxonomy
The interrogation of genetic markers in environmental meta-barcoding studies is currently seriously hindered by the lack of taxonomically curated reference data sets for the targeted genes. The Protist Ribosomal Reference database (PR2, http://ssu-rrna.org/) provides a unique access to eukaryotic small sub-unit (SSU) ribosomal RNA and DNA sequences, with curated taxonomy. The database mainly consists of nuclear-encoded protistan sequences. However, metazoans, land plants, macrosporic fungi and eukaryotic organelles (mitochondrion, plastid and others) are also included because they are useful for the analysis of high-troughput sequencing data sets. Introns and putative chimeric sequences have been also carefully checked. Taxonomic assignation of sequences consists of eight unique taxonomic fields. In total, 136 866 sequences are nuclear encoded, 45 708 (36 501 mitochondrial and 9657 chloroplastic) are from organelles, the remaining being putative chimeric sequences. The website allows the users to download sequences from the entire and partial databases (including representative sequences after clustering at a given level of similarity). Different web tools also allow searches by sequence similarity. The presence of both rRNA and rDNA sequences, taking into account introns (crucial for eukaryotic sequences), a normalized eight terms ranked-taxonomy and updates of new GenBank releases were made possible by a long-term collaboration between experts in taxonomy and computer scientist
Active nuclear import and cytoplasmic retention of activation-induced deaminase
The enzyme activation-induced deaminase (AID) triggers antibody diversification in B cells by catalyzing deamination and consequently mutation of immunoglobulin genes. To minimize off-target deamination, AID is restrained by several regulatory mechanisms including nuclear exclusion, thought to be mediated exclusively by active nuclear export. Here we identify two other mechanisms involved in controlling AID subcellular localization. AID is unable to passively diffuse into the nucleus, despite its small size, and its nuclear entry requires active import mediated by a conformational nuclear localization signal. We also identify in its C terminus a determinant for AID cytoplasmic retention, which hampers diffusion to the nucleus, competes with nuclear import and is crucial for maintaining the predominantly cytoplasmic localization of AID in steady-state conditions. Blocking nuclear import alters the balance between these processes in favor of cytoplasmic retention, resulting in reduced isotype class switching.This
work was supported by the Canadian Institutes of Health Research (MOP 84543)
and a Canada Research Chair (to J.M.D.). A.O. was supported by a fellowship
from the Canadian Institutes of Health Research Cancer Training Program at the
IRCM. V.A.C. was supported in part by a Michel Saucier fellowship from the
Louis-Pasteur Canadian Fund through the University of Montreal
Country-level gender inequality is associated with structural differences in the brains of women and men
男女間の不平等と脳の性差 --男女間の不平等は脳構造の性差と関連する--. 京都大学プレスリリース. 2023-05-10.Gender inequality across the world has been associated with a higher risk to mental health problems and lower academic achievement in women compared to men. We also know that the brain is shaped by nurturing and adverse socio-environmental experiences. Therefore, unequal exposure to harsher conditions for women compared to men in gender-unequal countries might be reflected in differences in their brain structure, and this could be the neural mechanism partly explaining women’s worse outcomes in gender-unequal countries. We examined this through a random-effects meta-analysis on cortical thickness and surface area differences between adult healthy men and women, including a meta-regression in which country-level gender inequality acted as an explanatory variable for the observed differences. A total of 139 samples from 29 different countries, totaling 7, 876 MRI scans, were included. Thickness of the right hemisphere, and particularly the right caudal anterior cingulate, right medial orbitofrontal, and left lateral occipital cortex, presented no differences or even thicker regional cortices in women compared to men in gender-equal countries, reversing to thinner cortices in countries with greater gender inequality. These results point to the potentially hazardous effect of gender inequality on women’s brains and provide initial evidence for neuroscience-informed policies for gender equality
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