638 research outputs found
Active site isolation in bismuth-poisoned Pd/SiO₂ catalysts for selective hydrogenation of furfural
Active site isolation in furfural (FA) hydrogenation was studied by poisoning a Pd catalyst with bismuth. A solution of FA in water was hydrogenated over a 5 wt% Pd/SiO₂ catalyst in a batch reactor at various reaction temperatures and pressures. Furfuryl alcohol (FAL) was an intermediate product which was further hydrogenated into tetrahydrofurfuryl alcohol (TFAL) or cyclopentanone (CPA) and cyclopentanol (CPOL). While application of hydrogen pressure above 30 bar had little effect on the hydrogenation kinetics, a reaction temperature affected product distribution and the main product changed from TFAL (at 50 °C) to FAL (100 and 150 °C). Poisoning the catalyst with Bi decreased the number of available active sites but had little effect on the turn-over frequencies, most likely because of the absence of electronic effects of Bi on Pd nanoparticles. The main reaction product over the Bi-poisoned catalyst was FAL with no FA oligomerisation products. At a reaction temperature of 150 °C, CPA was formed with a 57% yield. Considering that Bi preferentially poisons step sites of Pd, the comparison of the product distribution between the Pd and Pd-Bi catalyst as well as the literature data for the alloy Pd-Cu catalysts indicates that the active site isolation observed in the Pd-Bi catalysts is responsible for the increasing FAL and CPA selectivities and elimination of oligomer by-products
Sampling and contaminant monitoring protocol for raptors
In May 2013 representatives from six countries gathered in Murcia, Spain, to attend the Workshop on “Setting best practices on raptor contaminant monitoring activities in Europe” funded by EURAPMON. The workshop developed a rough draft of the current protocol. The protocol was subsequently completed with the involvement of investigators from Belgium, Denmark, France, Germany, The Netherlands, Norway, Spain, Sweden and the United Kingdom. All contributors are experts in monitoring contaminants in raptors.
The aim of this sampling protocol is to provide guidance on types of best practice that will facilitate harmonisation of procedures between existing and emerging schemes and so maximise the reliability, comparability and interoperability of data.The methods here do not require use of anaesthesia on birds. This protocol covers the sampling of blood and feathers from live birds, addled and deserted eggs, internal organs and tissues from dead specimens, and other samples such as faeces, preen oil and pellets.</p
The merger that led to the formation of the Milky Way's inner stellar halo and thick disk
The assembly process of our Galaxy can be retrieved using the motions and
chemistry of individual stars. Chemo-dynamical studies of the nearby halo have
long hinted at the presence of multiple components such as streams, clumps,
duality and correlations between the stars' chemical abundances and orbital
parameters. More recently, the analysis of two large stellar surveys have
revealed the presence of a well-populated chemical elemental abundance
sequence, of two distinct sequences in the colour-magnitude diagram, and of a
prominent slightly retrograde kinematic structure all in the nearby halo, which
may trace an important accretion event experienced by the Galaxy. Here report
an analysis of the kinematics, chemistry, age and spatial distribution of stars
in a relatively large volume around the Sun that are mainly linked to two major
Galactic components, the thick disk and the stellar halo. We demonstrate that
the inner halo is dominated by debris from an object which at infall was
slightly more massive than the Small Magellanic Cloud, and which we refer to as
Gaia-Enceladus. The stars originating in Gaia-Enceladus cover nearly the full
sky, their motions reveal the presence of streams and slightly retrograde and
elongated trajectories. Hundreds of RR Lyrae stars and thirteen globular
clusters following a consistent age-metallicity relation can be associated to
Gaia-Enceladus on the basis of their orbits. With an estimated 4:1 mass-ratio,
the merger with Gaia-Enceladus must have led to the dynamical heating of the
precursor of the Galactic thick disk and therefore contributed to the formation
of this component approximately 10 Gyr ago. These findings are in line with
simulations of galaxy formation, which predict that the inner stellar halo
should be dominated by debris from just a few massive progenitors.Comment: 19 pages, 8 figures. Published in Nature in the issue of Nov. 1st,
2018. This is the authors' version before final edit
Nut production in Bertholletia excelsa across a logged forest mosaic: implications for multiple forest use
Although many examples of multiple-use forest management may be found in tropical smallholder systems, few studies provide empirical support for the integration of selective timber harvesting with non-timber forest product (NTFP) extraction. Brazil nut (Bertholletia excelsa, Lecythidaceae) is one of the world’s most economically-important NTFP species extracted almost entirely from natural forests across the Amazon Basin. An obligate out-crosser, Brazil nut flowers are pollinated by large-bodied bees, a process resulting in a hard round fruit that takes up to 14 months to mature. As many smallholders turn to the financial security provided by timber, Brazil nut fruits are increasingly being harvested in logged forests. We tested the influence of tree and stand-level covariates (distance to nearest cut stump and local logging intensity) on total nut production at the individual tree level in five recently logged Brazil nut concessions covering about 4000 ha of forest in Madre de Dios, Peru. Our field team accompanied Brazil nut harvesters during the traditional harvest period (January-April 2012 and January-April 2013) in order to collect data on fruit production. Three hundred and ninety-nine (approximately 80%) of the 499 trees included in this study were at least 100 m from the nearest cut stump, suggesting that concessionaires avoid logging near adult Brazil nut trees. Yet even for those trees on the edge of logging gaps, distance to nearest cut stump and local logging intensity did not have a statistically significant influence on Brazil nut production at the applied logging intensities (typically 1–2 timber trees removed per ha). In one concession where at least 4 trees ha-1 were removed, however, the logging intensity covariate resulted in a marginally significant (0.09) P value, highlighting a potential risk for a drop in nut production at higher intensities. While we do not suggest that logging activities should be completely avoided in Brazil nut rich forests, when a buffer zone cannot be observed, low logging intensities should be implemented. The sustainability of this integrated management system will ultimately depend on a complex series of socioeconomic and ecological interactions. Yet we submit that our study provides an important initial step in understanding the compatibility of timber harvesting with a high value NTFP, potentially allowing for diversification of forest use strategies in Amazonian Perù
Problematic Internet Use in University Students: associated factors and differences of gender
El objetivo del presente trabajo es realizar un análisis descriptivo del uso problemático de Internet en estudiantes universitarios, evaluando la posible asociación con problemas de salud y conductas adictivas, así como diferencias de género en los tipos utilización. Un total de 2780 alumnos participaron en el estudio entre los años 2011 – 2014, siendo un 29% varones (edad 20.8 ± 5.1 años) y un 71% mujeres (edad de 20.3 ± 4.4 años). La prevalencia de uso problemático de Internet evaluada mediante el Internet Addiction Test fue del 6.08%. Ser menor de 21 años y cursar titulaciones diferentes a ciencias de la salud fueron factores asociados a una mayor frecuencia de este problema, no existiendo diferencias en función del sexo o tipo de domicilio. Los resultados muestran una asociación significativa con algunos problemas de salud (migrañas, dolor lumbar, sobrepeso u obesidad, descanso insuficiente), aspectos psicológicos (riesgo de trastornos de la conducta alimentaria, riesgo de trastorno mental, depresión), problemas familiares y discriminación; no encontrándose asociaciones con consumo de sustancias adictivas (alcohol, tabaco o cannabis). Respecto al tiempo de uso de Internet, las horas de conexión semanales fueron significativamente mayores en las mujeres que en los hombres, tanto en el tiempo total como por motivos de ocio. El análisis del perfil de utilización en usuarios problemáticos reveló que los varones se relacionan más con aspectos de ocio como los juegos o las compras online y las mujeres con aspectos de socialización, como el chat o las redes sociales
High prevalence and diversity of HIV-1 non-B genetic forms due to immigration in southern Spain: A phylogeographic approach
Phylogenetic studies are a valuable tool to understand viral transmission patterns and the role of immigration in HIV-1 spread. We analyzed the spatio-temporal relationship of different HIV-1 non-B subtype variants over time using phylogenetic analysis techniques. We collected 693 pol (PR+RT) sequences that were sampled from 2005 to 2012 from naïve patients in different hospitals in southern Spain. We used REGA v3.0 to classify them into subtypes and recombinant forms, which were confirmed by phylogenetic analysis through maximum likelihood (ML) using RAxML. For the main HIV-1 non-B variants, publicly available, genetically similar sequences were sought using HIV-BLAST. The presence of HIV-1 lineages circulating in our study population was established using ML and Bayesian inference (BEAST v1.7.5) and transmission networks were identified. We detected 165 (23.4%) patients infected with HIV-1 non-B variants: 104 (63%) with recombinant viruses in pol: CRF02_AG (71, 43%), CRF14_BG (8, 4.8%), CRF06_cpx (5, 3%) and nine other recombinant forms (11, 6.7%) and unique recombinants (9, 5.5%). The rest (61, 37%) were infected with non-recombinant subtypes: A1 (30, 18.2%), C (7, [4.2%]), D (3, [1.8%]), F1 (9, 5.5%) and G (12, 7.3%). Most patients infected with HIV-1 non-B variants were men (63%, p < 0.001) aged over 35 (73.5%, p < 0.001), heterosexuals (92.2%, p < 0.001), from Africa (59.5%, p < 0.001) and living in the El Ejido area (62.4%, p<0.001). We found lineages of epidemiological relevance (mainly within Subtype A1), imported primarily through female sex workers from East Europe. We detected 11 transmission clusters of HIV-1 non-B Subtypes, which included patients born in Spain in half of them. We present the phylogenetic profiles of the HIV-1 non-B variants detected in southern Spain, and explore their putative geographical origins. Our data reveals a high HIV-1 genetic diversity likely due to the import of viral lineages that circulate in other countries. The highly immigrated El Ejido area acts as a gateway through which different subtypes are introduced into other regions, hence the importance of setting up epidemiological control measures to prevent future outbreaks
Medically unexplained pain complaints are associated with underlying unrecognized mood disorders in primary care
<p>Abstract</p> <p>Background</p> <p>Patients with chronic pain frequently display comorbid depression, but the impact of this concurrence is often underestimated and mistreated. The aim of this study was to determine the prevalence of unrecognized major depression and other mood disorders and comorbid unexplained chronic pain in primary care settings and to explore the associated factors.</p> <p>Also, to compare the use of health services by patients with unexplained chronic pain, both with and without mood disorder comorbidity.</p> <p>Methods</p> <p>A cross-sectional study was carried out in a sample of primary care centers. 3189 patients consulting for "unexplained chronic pain" were assessed by the Visual Analogue Scales (VAS) and the Primary Care Evaluation of Mental Disorders (PRIME-MD) questionnaire.</p> <p>Results</p> <p>We report: a) a high prevalence of unrecognized mood disorders in patients suffering from unexplained chronic pain complaints (80.4%: CI 95%: 79.0%; 81.8%); b) a greater susceptibility of women to mood disorders (OR adjusted = 1.48; CI 95%:1.22; 1.81); c) a direct relationship between the prevalence of mood disorders and the duration of pain (OR adjusted = 1.01; CI 95%: 1.01; 1.02) d) a higher comorbidity with depression if the pain etiology was unknown (OR adjusted = 1.74; CI 95%: 1.45; 2.10) and, e) an increased use of health care services in patients with such a comorbidity (p < 0.0001).</p> <p>Conclusions</p> <p>The prevalence of undiagnosed mood disorders in patients with unexplained chronic pain in primary care is very high, leading to dissatisfaction with treatment processes and poorer outcomes. Consequently, it seems necessary to explore this condition more regularly in general practice in order to reach accurate diagnoses and to select the appropriate treatment.</p
Hepatoprotection and neuroprotection induced by low doses of IGF-II in aging rats
<p>Abstract</p> <p>Background</p> <p>GH and IGFs serum levels decline with age. Age-related changes appear to be associated to decreases in these anabolic hormones. We have previously demonstrated that IGF-I replacement therapy improves insulin resistance, lipid metabolism and reduces oxidative damage (in brain and liver) in aging rats. Using the same experimental model, the aim of this work was to study whether the exogenous administration of IGF-II, at low doses, acts analogous to IGF-I in aging rats.</p> <p>Methods</p> <p>Three experimental groups were included in this study: young healthy controls (yCO, 17 weeks old); untreated old rats (O, 103 weeks old); and aging rats treated with IGF-II (O+IGF-II, 2 μg * 100 g body weight<sup>-1 </sup>* day<sup>-1</sup>) for 30 days. Analytical parameters were determined in serum by routine laboratory methods using an autoanalyzer (Cobas Mira; Roche Diagnostic System, Basel, Switzerland). Serum levels of hormones (testosterone, IGF-I and insulin) were assessed by RIA. Serum Total Antioxidant Status was evaluated using a colorimetric assay. Mitochondrial membrane potential was evaluated using rhodamine 123 dye (adding different substrates to determine the different states). ATP synthesis in isolated mitochondria was determined by an enzymatic method.</p> <p>Results</p> <p>Compared with young controls, untreated old rats showed a reduction of IGF-I and testosterone levels with a decrease of serum total antioxidant status (TAS). IGF-II therapy improved serum antioxidant capability without modifying testosterone and IGF-I circulating concentrations. In addition, IGF-II treatment reduced oxidative damage in brain and liver, improving antioxidant enzyme activities and mitochondrial function. IGF-II was also able to reduce cholesterol and triglycerides levels increasing free fatty acids concentrations.</p> <p>Conclusions</p> <p>We demonstrate that low doses of IGF-II induce hepatoprotective, neuroprotective and metabolic effects, improving mitochondrial function, without affecting testosterone and IGF-I levels.</p
Anthropic resource exploitation and use of the territory at the onset of social complexity in the Neolithic-Chalcolithic Western Pyrenees: a multi-isotope approach
Carbon (δ13C) and nitrogen (δ15N) stable isotope analyses from bone collagen provide information about the dietary protein input, while strontium isotopes (87Sr/86Sr) from tooth enamel give us data about provenance and potential territorial mobility of past populations. To date, isotopic results on the prehistory of the Western Pyrenees are scarce. In this article, we report human and faunal values of the mentioned isotopes from the Early-Middle Neolithic site of Fuente Hoz (Anuntzeta) and the Late Neolithic/Early Chalcolithic site of Kurtzebide (Letona, Zigoitia). The main objectives of this work are to analyze the dietary and territorial mobility patterns of these populations. Furthermore, as an additional aim, we will try to discuss social ranking based on the isotope data and existing literature on this topic in the region of study. Our results show that, based on the bioavailable Sr values, both purported local and non-local humans were buried together at the sites. Additionally, they suggest similar resource consumption based on C3 terrestrial resources (i.e. ovicaprids, bovids, and suids) as the main part of the protein input. Overall, this study sheds light on how individuals from different backgrounds were still buried together and shared the same dietary lifestyle at a time in the Prehistory of Iberia when social complexities started to appear
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