11,064 research outputs found
Estatus de la gestión de riesgos climáticos en el sector agroalimentario y su importancia para la seguridad alimentaria y nutricional en Honduras
Honduras ha sido identificado como el país con mayor vulnerabilidad en términos de riesgo, variabilidad y cambio climático de Centroamérica; es por esto que la Secretaría de Agricultura y Ganadería (SAG) en colaboración con el Programa de Investigación de CGIAR en Cambio
Climático, Agricultura y Seguridad Alimentaria (CCAFS) en América Latina y con apoyo del Consejo Agropecuario Centroamericano (CAC) presentan el estatus de la investigación en cambio climático, agricultura y seguridad alimentaria, así como el marco gubernamental y actores involucrados en torno a esta temática. El documento evidencia que el país cuenta con una estructura legal e
institucional que promueve políticas y acciones orientadas a contrarrestar los efectos negativos de éste fenómeno, colaborando continuamente con organizaciones internacionales, academia y sector privado, sin embargo se mantiene en continuo proceso de desarrollo y mejora para incrementar la resiliencia y adaptación al cambio climático así como la mitigación del sector agrícola hondureño
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Complementary Metagenomic Approaches Improve Reconstruction of Microbial Diversity in a Forest Soil.
Soil ecosystems harbor diverse microorganisms and yet remain only partially characterized as neither single-cell sequencing nor whole-community sequencing offers a complete picture of these complex communities. Thus, the genetic and metabolic potential of this "uncultivated majority" remains underexplored. To address these challenges, we applied a pooled-cell-sorting-based mini-metagenomics approach and compared the results to bulk metagenomics. Informatic binning of these data produced 200 mini-metagenome assembled genomes (sorted-MAGs) and 29 bulk metagenome assembled genomes (MAGs). The sorted and bulk MAGs increased the known phylogenetic diversity of soil taxa by 7.2% with respect to the Joint Genome Institute IMG/M database and showed clade-specific sequence recruitment patterns across diverse terrestrial soil metagenomes. Additionally, sorted-MAGs expanded the rare biosphere not captured through MAGs from bulk sequences, exemplified through phylogenetic and functional analyses of members of the phylum Bacteroidetes Analysis of 67 Bacteroidetes sorted-MAGs showed conserved patterns of carbon metabolism across four clades. These results indicate that mini-metagenomics enables genome-resolved investigation of predicted metabolism and demonstrates the utility of combining metagenomics methods to tap into the diversity of heterogeneous microbial assemblages.IMPORTANCE Microbial ecologists have historically used cultivation-based approaches as well as amplicon sequencing and shotgun metagenomics to characterize microbial diversity in soil. However, challenges persist in the study of microbial diversity, including the recalcitrance of the majority of microorganisms to laboratory cultivation and limited sequence assembly from highly complex samples. The uncultivated majority thus remains a reservoir of untapped genetic diversity. To address some of the challenges associated with bulk metagenomics as well as low throughput of single-cell genomics, we applied flow cytometry-enabled mini-metagenomics to capture expanded microbial diversity from forest soil and compare it to soil bulk metagenomics. Our resulting data from this pooled-cell sorting approach combined with bulk metagenomics revealed increased phylogenetic diversity through novel soil taxa and rare biosphere members. In-depth analysis of genomes within the highly represented Bacteroidetes phylum provided insights into conserved and clade-specific patterns of carbon metabolism
Quantum fluctuations in high field magnetization of 2D square lattice J1-J2 antiferromagnets
The J1-J2 square lattice Heisenberg model with spin S=1/2 has three phases
with long-range magnetic order and two unconventionally ordered phases
depending on the ratio of exchange constants. It describes a number of recently
found layered vanadium oxide compounds. A simple means of investigating the
ground state is the study of the magnetization curve and high-field
susceptibility. We discuss these quantities by using the spin-wave theory and
the exact diagonalization in the whole J1-J2 plane. We compare both results and
find good overall agreement in the sectors of the phase diagram with magnetic
order. Close to the disordered regions the magnetization curve shows strong
deviations from the classical linear behaviour caused by large quantum
fluctuations and spin-wave approximation breaks down. On the FM side (J1<0)
where one approaches the quantum gapless spin nematic ground state this region
is surprisingly large. We find that inclusion of second order spin-wave
corrections does not lead to fundamental improvement. Quantum corrections to
the tilting angle of the ordered moments are also calculated. They may have
both signs, contrary to the always negative first order quantum corrections to
the magnetization. Finally we investigate the effect of the interlayer coupling
and find that the quasi-2D picture remains valid up to |J_\perp/J1| ~ 0.3.Comment: 13 pages, 6figure
Methane storms as a driver of Titan's dune orientation
Titan's equatorial regions are covered by eastward propagating linear dunes.
This direction is opposite to mean surface winds simulated by Global Climate
Models (GCMs), which are oriented westward at these latitudes, similar to trade
winds on Earth. Different hypotheses have been proposed to address this
apparent contradiction, involving Saturn's gravitational tides, large scale
topography or wind statistics, but none of them can explain a global eastward
dune propagation in the equatorial band. Here we analyse the impact of
equinoctial tropical methane storms developing in the superrotating atmosphere
(i.e. the eastward winds at high altitude) on Titan's dune orientation. Using
mesoscale simulations of convective methane clouds with a GCM wind profile
featuring superrotation, we show that Titan's storms should produce fast
eastward gust fronts above the surface. Such gusts dominate the aeolian
transport, allowing dunes to extend eastward. This analysis therefore suggests
a coupling between superrotation, tropical methane storms and dune formation on
Titan. Furthermore, together with GCM predictions and analogies to some
terrestrial dune fields, this work provides a general framework explaining
several major features of Titan's dunes: linear shape, eastward propagation and
poleward divergence, and implies an equatorial origin of Titan's dune sand.Comment: Published online on Nature Geoscience on 13 April 201
Investigating the association between obesity and asthma in 6- to 8-year-old Saudi children:a matched case-control study
Background: Previous studies have demonstrated an association between obesity and asthma, but there remains considerable uncertainty about whether this reflects an underlying causal relationship. Aims: To investigate the association between obesity and asthma in pre-pubertal children and to investigate the roles of airway obstruction and atopy as possible causal mechanisms. Methods: We conducted an age- and sex-matched case–control study of 1,264 6- to 8-year-old schoolchildren with and without asthma recruited from 37 randomly selected schools in Madinah, Saudi Arabia. The body mass index (BMI), waist circumference and skin fold thickness of the 632 children with asthma were compared with those of the 632 control children without asthma. Associations between obesity and asthma, adjusted for other potential risk factors, were assessed separately in boys and girls using conditional logistic regression analysis. The possible mediating roles of atopy and airway obstruction were studied by investigating the impact of incorporating data on sensitisation to common aeroallergens and measurements of lung function. Results: BMI was associated with asthma in boys (odds ratio (OR)=1.14, 95% confidence interval (CI), 1.08–1.20; adjusted OR=1.11, 95% CI, 1.03–1.19) and girls (OR=1.37, 95% CI, 1.26–1.50; adjusted OR=1.38, 95% CI, 1.23–1.56). Adjusting for forced expiratory volume in 1 s had a negligible impact on these associations, but these were attenuated following adjustment for allergic sensitisation, particularly in girls (girls: OR=1.25; 95% CI, 0.96–1.60; boys: OR=1.09, 95% CI, 0.99–1.19). Conclusions: BMI is associated with asthma in pre-pubertal Saudi boys and girls; this effect does not appear to be mediated through respiratory obstruction, but in girls this may at least partially be mediated through increased risk of allergic sensitisation
Quantum Non-Demolition Detection of Strongly Correlated Systems
Preparation, manipulation, and detection of strongly correlated states of
quantum many body systems are among the most important goals and challenges of
modern physics. Ultracold atoms offer an unprecedented playground for
realization of these goals. Here we show how strongly correlated states of
ultracold atoms can be detected in a quantum non-demolition scheme, that is, in
the fundamentally least destructive way permitted by quantum mechanics. In our
method, spatially resolved components of atomic spins couple to quantum
polarization degrees of freedom of light. In this way quantum correlations of
matter are faithfully mapped on those of light; the latter can then be
efficiently measured using homodyne detection. We illustrate the power of such
spatially resolved quantum noise limited polarization measurement by applying
it to detect various standard and "exotic" types of antiferromagnetic order in
lattice systems and by indicating the feasibility of detection of superfluid
order in Fermi liquids.Comment: Published versio
Optogenetics and deep brain stimulation neurotechnologies
Brain neural network is composed of densely packed, intricately wired neurons whose activity patterns ultimately give rise to every behavior, thought, or emotion that we experience. Over the past decade, a novel neurotechnique, optogenetics that combines light and genetic methods to control or monitor neural activity patterns, has proven to be revolutionary in understanding the functional role of specific neural circuits. We here briefly describe recent advance in optogenetics and compare optogenetics with deep brain stimulation technology that holds the promise for treating many neurological and psychiatric disorders
Three-Dimensional Handheld Scanning to Quantify Head-Shape Changes in Spring-Assisted Surgery for Sagittal Craniosynostosis
Three-dimensional (3D) imaging is an important tool for diagnostics, surgical planning, and evaluation of surgical outcomes in craniofacial procedures. Gold standard for acquiring 3D imaging is computed tomography that entails ionizing radiations and, in young children, a general anaesthesia. Three-dimensional photographic imaging is an alternative method to assess patients who have undergone calvarial reconstructive surgery. The aim of this study was to assess the utility of 3D handheld scanning photography in a cohort of patients who underwent spring-assisted correction surgery for scaphocephaly. Pre- and postoperative 3D scans acquired in theater and at the 3-week follow-up in clinic were postprocessed for 9 patients. Cephalic index (CI), head circumference, volume, sagittal length, and coronal width over the head at pre-op, post-op, and follow-up were measured from the 3D scans. Cephalic index from 3D scans was compared with measurements from planar x-rays. Statistical shape modeling (SSM) was used to calculate the 3D mean anatomical head shape of the 9 patients at the pre-op, post-op, and follow-up. No significant differences were observed in the CI between 3D and x-ray. Cephalic index, volume, and coronal width increased significantly over time. Mean shapes from SSM visualized the overall and regional 3D changes due to the expansion of the springs in situ. Three-dimensional handheld scanning followed by SSM proved to be an efficacious and practical method to evaluate 3D shape outcomes after spring-assisted cranioplasty in individual patients and the population
Active wetting of epithelial tissues
Development, regeneration and cancer involve drastic transitions in tissue
morphology. In analogy with the behavior of inert fluids, some of these
transitions have been interpreted as wetting transitions. The validity and
scope of this analogy are unclear, however, because the active cellular forces
that drive tissue wetting have been neither measured nor theoretically
accounted for. Here we show that the transition between 2D epithelial
monolayers and 3D spheroidal aggregates can be understood as an active wetting
transition whose physics differs fundamentally from that of passive wetting
phenomena. By combining an active polar fluid model with measurements of
physical forces as a function of tissue size, contractility, cell-cell and
cell-substrate adhesion, and substrate stiffness, we show that the wetting
transition results from the competition between traction forces and contractile
intercellular stresses. This competition defines a new intrinsic lengthscale
that gives rise to a critical size for the wetting transition in tissues, a
striking feature that has no counterpart in classical wetting. Finally, we show
that active shape fluctuations are dynamically amplified during tissue
dewetting. Overall, we conclude that tissue spreading constitutes a prominent
example of active wetting --- a novel physical scenario that may explain
morphological transitions during tissue morphogenesis and tumor progression
Optimizing CIGB-300 intralesional delivery in locally advanced cervical cancer
Background:We conducted a phase 1 trial in patients with locally advanced cervical cancer by injecting 0.5 ml of the CK2-antagonist CIGB-300 in two different sites on tumours to assess tumour uptake, safety, pharmacodynamic activity and identify the recommended dose.Methods:Fourteen patients were treated with intralesional injections containing 35 or 70 mg of CIGB-300 in three alternate cycles of three consecutive days each before standard chemoradiotherapy. Tumour uptake was determined using 99 Tc-radiolabelled peptide. In situ B23/nucleophosmin was determined by immunohistochemistry.Results:Maximum tumour uptake for CIGB-300 70-mg dose was significantly higher than the one observed for 35 mg: 16.1±8.9 vs 31.3±12.9 mg (P=0.01). Both, AUC 24h and biological half-life were also significantly higher using 70 mg of CIGB-300 (P<0.001). Unincorporated CIGB-300 diffused rapidly to blood and was mainly distributed towards kidneys, and marginally in liver, lungs, heart and spleen. There was no DLT and moderate allergic-like reactions were the most common systemic side effect with strong correlation between unincorporated CIGB-300 and histamine levels in blood. CIGB-300, 70 mg, downregulated B23/nucleophosmin (P=0.03) in tumour specimens.Conclusion:Intralesional injections of 70 mg CIGB-300 in two sites (0.5 ml per injection) and this treatment plan are recommended to be evaluated in phase 2 studies.Fil: Sarduy, M. R.. Medical-surgical Research Center; CubaFil: García, I.. Centro de Ingeniería Genética y Biotecnología; CubaFil: Coca, M. A.. Clinical Investigation Center; CubaFil: Perera, A.. Clinical Investigation Center; CubaFil: Torres, L. A.. Clinical Investigation Center; CubaFil: Valenzuela, C. M.. Centro de Ingeniería Genética y Biotecnología; CubaFil: Baladrón, I.. Centro de Ingeniería Genética y Biotecnología; CubaFil: Solares, M.. Hospital Materno Ramón González Coro; CubaFil: Reyes, V.. Center For Genetic Engineering And Biotechnology Havana; CubaFil: Hernández, I.. Isotope Center; CubaFil: Perera, Y.. Centro de Ingeniería Genética y Biotecnología; CubaFil: Martínez, Y. M.. Medical-surgical Research Center; CubaFil: Molina, L.. Medical-surgical Research Center; CubaFil: González, Y. M.. Medical-surgical Research Center; CubaFil: Ancízar, J. A.. Centro de Ingeniería Genética y Biotecnología; CubaFil: Prats, A.. Clinical Investigation Center; CubaFil: González, L.. Centro de Ingeniería Genética y Biotecnología; CubaFil: Casacó, C. A.. Clinical Investigation Center; CubaFil: Acevedo, B. E.. Centro de Ingeniería Genética y Biotecnología; CubaFil: López Saura, P. A.. Centro de Ingeniería Genética y Biotecnología; CubaFil: Alonso, Daniel Fernando. Universidad Nacional de Quilmes; ArgentinaFil: Gómez, R.. Elea Laboratories; ArgentinaFil: Perea Rodríguez, S. E.. Center For Genetic Engineering And Biotechnology Havana; Cuba. Centro de Ingeniería Genética y Biotecnología; Cub
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