8,721 research outputs found
Reflectance measurements of cotton leaf senescence altered by mepiquat chloride
Spectrophotometric reflectance measurements were made on plant-attached leaves to evaluate growth chamber-grown cotton leaf (Gossypium hirsutum L.) senescence (chlorophyll degradation as criterion) that was delayed by mepiquat chloride (1,1-dimethylpiperidinium chloride) rates of 0, 10, 40, 70, and 100 g a.i./ha. Mepiquat chloride (MC increased both chlorophyll and leaf water contents as compared with that of untreated leaves. Reflectance was inversely and linearly correlated (r = -0.873**) with eater content at the 1.65 micrometer wavelength and was inversely correlated (r = -0.812**) with chlorophyll concentration at the 0.55 micrometer wavelength but best fit a quadratic equation. Either wavelength measurement might be useful to remotely detect cotton leaf senescence or fields of MC-treated cotton plants
Increase of cold tolerance in cotton plant (Gossypium hirsutum L.) by mepiquat chloride
Three mepiquat chloride (MC) concentrations - 40, 70, and 100 g a.i./ha - were used to spray cotton (Gossypium hirsutum L., cultival McNair 220) plants to determine whether or not MC would increase their cold tolerance. Seven to ten days after the spray, the plants were exposed to three different cold treatments. No important difference in cold damage was noticed between the control and the MC-treated plants when they were exposed repeatedly to 4.5 C. No plants died when exposed to 0.5 C for 12 h; however, 90% of the 1st and 2nd leaves of the control plants were damaged. This was three times more damage than those leaves of plants treated with 70 and 100 g a.i./ha MC concentrations; 60% f the control and 10-20% of the MC-treated plants died when the plants were subjected to a cold hardening process with 15.5 C day (12 h) and 1.7 C night (12 h) for 10 days, and then, held at -2.2 C for 24 hours. The electrolyte leakage and reflectance measurement data showed that the cell membranes of the MC-treated plants sustained much less damage than those of the control. Freezing injury was easily assessed by reflectance measurements at the 1.65 micrometer wavelength
Synthesis and characterization of silver vanadates thin films for photocatalytic applications
Silver vanadates thin films were deposited by a hybrid deposition system combining laser ablation and thermal evaporation. A high purity vanadium target was ablated using the third harmonic of a Nd:YAG laser whereas high purity silver pellets were evaporated. The as-deposited thin films were subjected to thermal treatments at 400 °C to obtain crystalline films. For films without Ag amorphous V2O5 thin films were deposited and as the Ag is incorporated in the material different silver vanadates were obtained. The effect of the silver load on the composition, structure, optical properties, surface morphology and photocatalytic response of the deposited films was studied. The film composition, determined by X-ray photoelectron spectroscopy, reveals Ag contents from 5.5 to 18.9 at.%. The crystalline phases formed were identified by micro-Raman Spectroscopy; the results indicate the formation of three silver vanadates depending on the silver content. The morphology was observed using scanning electron microscopy, the filmś surface changes from a smooth surface to belts covering the surface and finally Ag nanoparticles are observed at the higher Ag contens. Optical properties determined from UV–vis reveal the presence of the surface plasmon signal in films containing silver. The films were tested in the photocatalytic degradation of Malachite Green dye reaching maximum degradations degrees close to 53% under solar irradiation. Reactive species trapping experiments suggest that O2 − produced by the O2 reduction via the photogenerated electrons drives the photodegradation mechanismCB-168827 CB-240998 F. Gonzalez-Zavala thanks to CONACyT for the PhD and Beca Mixta grants, and also to the SIEA-UAEM for the beca movilidad para estudios avanzados 2016. E. Rodríguez-Castellón thanks to project CTQ2015-68951-C3-3-R of Ministerio de Economía y Competitividad (Spain) and FEDER funds
Sleeping-tree fidelity of the spider monkey shapes community-level seed-rain patterns in continuous and fragmented rain forests
Repeated use of sleeping trees (STs) by frugivores promotes the deposition and aggregation of copious amounts of seed, thus having key implications for seed dispersal and forest regeneration. Seed-rain patterns produced by this behaviour likely depend on the frequency of use of these sites, yet this hypothesis has been poorly tested. We evaluated community-level seed-rain patterns produced by the spider monkey (Ateles geoffroyi) over 13 mo in latrines located beneath 60 STs in the Lacandona rain forest, Mexico. Because this primate is increasingly ‘forced’ to inhabit fragmented landscapes, we tested whether sleeping-tree fidelity (STF) differed among sites and between continuous and fragmented forests. We also tested whether seed-rain patterns were associated with STF within each site and forest type. STF was highly variable among STs (average = 7 mo, range = 1–12 mo), but did not differ among study sites or forest types. STF was positively associated with seed abundance, species diversity and species turnover. Nevertheless, STF tended to be negatively related to seed community evenness. These results are likely due to the most frequently used STs being in areas with greater food density. Our results demonstrate that site fidelity shapes community-level seed-rain patterns and thus has key ecological implications
Culturally relevant social work services for latinas infected or affected with HIV/AIDS.
As we begin the third decade of the HIV/AIDS pandemic, concerns continue about social, psychological, and behavioral aspects of the living with the illness. What was once thought to be predominately a gay, Anglo disease has now become prominent in the heterosexual population crossing all racial and class lines. Presumed injection drug users have always been highly infected. However, studies show that HIV/AIDS is affecting different populations at shockingly disproportionate rates. The HIV/AIDS pandemic in the United States is disproportionately represented and is growing at a faster rate in ethnic minority communities as compared to majority populations (Centers for Disease Control and Prevention [CDC], 2002). The purpose of this article is to explore the specific issues associated with HIV/AIDS in racial and ethnic minorities, with a specific focus on how the increase of new AIDS cases is affecting Latinas. Disparities such as lack of access to medical care and unique socio-cultural issues are discussed, followed by implications for social work practice, policy, research, and education
Suppression of NYVAC infection in hela cells requires RNase L but is independent of protein kinase R activity
Protein kinase R (PKR) and RNase L are host cell components that function to contain viral spread after infections. In this study, we analyzed the role of both proteins in the abortive infection of human HeLa cells with the poxvirus strain NYVAC, for which an inhibition of viral A27L and B5R gene expression is described. Specifically, the translation of these viral genes is independent of PKR activation, but their expression is dependent on the RNase L activityThis work was supported by grants from the Spanish Ministry of
Health (FIS2011-00127) and Bayer Group Grants4Grants (2013-08-0982
to S.G., SAF2008-02036 to M.E., and AGL2010-15495 to D.R.
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Nocebo Effect in Randomized Clinical Trials of Antidepressants in Children and Adolescents: Systematic Review and Meta-Analysis
Objective:: To compare the incidence of adverse events between active and placebo arms of randomized clinical trials in depressive children and adolescents (C&A) with antidepressant treatments, in order to look for similarities in both groups that allow to establish a possible nocebo effect. Methods:: Systematic search strategy (January 1974–March 2013) in electronic databases, conference abstracts, and reference list of systematic reviews and included studies to identify parallel randomized placebo-controlled trials of antidepressants in C&A (<19 years) with major depressive disorder, and one or more interventions of any orally administered antidepressant. The pooled adverse events were calculated based on a fixed-effect model and statistical analysis involved the risk ratio (RR) of adverse events, with 95% confidence intervals (95% CI). Results:: Sixteen studies were included in the review, of which seven studies with a sample of 1911 patients had data to include in the meta-analysis. There was similar risk for the incidence of adverse events between non-active and active group (global RR 1.04, 95% CI: 0.97–1.11). Conclusion:: Depressive C&A allocated to placebo or active group had similar risk to develop adverse events. These similarities in both groups are attributed to the nocebo effect. It is of note that defining “nocebo” effects is challenging in clinical populations because adverse effects may be attributed to the intervention or may be manifestation of the disease itself. The inclusion of a no-treatment arm may be warranted. Nocebo effects are likely when adverse events of placebo mimic the adverse events of active treatment, as was the case here
Investigating the experience of Moodle adoption through expert voices
Virtual learning environments (VLEs) such as Moodle are now widely used in universities and other organisations. One crucial factor in the successful employment of such platforms is the ability and commitment of teaching staff to adopt the system. Despite the importance of this role, there has been little work to examine the experience of using VLEs in practice. This paper presents initial, qualitative research aimed at understanding how Moodle is being used and the different experiences and perspectives of the staff involved. To generate themes and areas of interest for future investigation this paper uses interview data from two “expert witnesses” who have a deep understanding of how the platform is used. Emergent themes include: divergence between confident and basic users; the spread of usage within an academic community; lack of progression to innovative teaching methods
Relativistic screened hydrogenic radial integrals
The computation of dipole matrix elements plays an important role in the study of absorption or emission of radiation by atoms in several fields such as astrophysics or inertial confinement fusion. In this work we obtain closed formulas for the dipole matrix elements of multielectron ions suitable for using in the framework of a Relativistic Screened Hydrogenic Model
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