221 research outputs found

    Alternativa agroecológica para el control del tizón tardío, Phytophthora infestans, de la papa en Colomi - Bolivia

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    En el Cantón Candelaria, Municipio de Colomi, del Departamento deCochabamba, existe un microcentro de biodiversidad donde se cultivan entre 60-70variedades de papa que son susceptibles a numerosas plagas, como el tizón tardío(Phytophthora infestans). Esta plaga ocasiona pérdidas hasta del 70 % del cultivo. Paracontrolar el tizón tardío, el agricultor, por falta de conocimiento y recursoseconómicos, hace un uso inadecuado de fungicidas. Se propuso un tratamientoagroecológico para el control del tizón tardío, se lo comparó con el tratamientoquímico (7 aplicaciones de fungicida sistémico y de contacto) y el tratamiento queaplica el agricultor (4 aplicaciones de fungicida sistémico), en dos sistemas deproducción (ladera y pampa). Para el tratamiento agroecológico, se combinaron:extracto de cola de caballo (Equisetum giganteum L.), caldo Bordelés y un fungicidaquímico de baja toxicidad (2 aplicaciones del fungicida sistémico con ingrediente activoMetalaxyl-M Mancoceb). Se analizó el rendimiento, la relación de costo/beneficio y losefectos sobre el medio ambiente de los tres tratamientos. Además, se analizó el efectode un fertilizante químico (fosfato diamónio y urea) y de un fertilizante orgánico(gallinaza), sobre el rendimiento de papa. El tratamiento agroecológico resulto ser eltratamiento más rentable (aprox. $US 380 ha-1) y más eficiente en el control del tizóntardío, con un rendimiento de papa (23 t ha-1), similar al obtenido mediante el controlquímico. Además, el tratamiento agroecológico representa el menor riesgo para elagricultor y el medio ambiente

    Private and public modes of bicycle commuting: a perspective on attitude and perception

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    BACKGROUND: Public bicycle-sharing initiatives can act as health enhancement strategies among urban populations. The aim of the study was to determine which attitudes and perceptions of behavioural control toward cycling and a bicycle-sharing system distinguish commuters with a different adherence to bicycle commuting. METHODS: The recruitment process was conducted in 40 random points in Barcelona from 2011 to 2012. Subjects completed a telephone-based questionnaire including 27 attitude and perception statements. Based on their most common one-way commute trip and willingness to commute by bicycle, subjects were classified into Private Bicycle (PB), public bicycle or Bicing Bicycle (BB), Willing Non-bicycle (WN) and Non-willing Non-bicycle (NN) commuters. After reducing the survey statements through principal component analysis, a multinomial logistic regression model was obtained to evaluate associations between attitudinal and commuter sub-groups. RESULTS: We included 814 adults in the analysis [51.6% female, mean (SD): age 36.6 (10.3) years]. BB commuters were 2.0 times [95% confidence interval (CI) = 1.1-3.7] less likely to perceive bicycle as a quick, flexible and enjoyable mode compared to PB. BB, WN and NN were 2.5 (95% CI = 1.46-4.24), 2.6 (95% CI = 1.53-4.41) and 2.3 times (95% CI = 1.30-4.10) more likely to perceive benefits of using public bicycles (bicycle maintenance and parking avoidance, low cost and no worries about theft and vandalism) than did PB. CONCLUSION: Willing non-bicycle and public-bicycle commuters had more favourable perception toward public-shared bicycles compared to private cyclists. Hence, public bicycles may be the impetus for those willing to start bicycle commuting, thereby increasing physical activity levels

    The EMPIRE Survey: Systematic Variations in the Dense Gas Fraction and Star Formation Efficiency from Full-Disk Mapping of M51

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    We present the first results from the EMPIRE survey, an IRAM large program that is mapping tracers of high density molecular gas across the disks of nine nearby star-forming galaxies. Here, we present new maps of the 3-mm transitions of HCN, HCO+, and HNC across the whole disk of our pilot target, M51. As expected, dense gas correlates with tracers of recent star formation, filling the "luminosity gap" between Galactic cores and whole galaxies. In detail, we show that both the fraction of gas that is dense, f_dense traced by HCN/CO, and the rate at which dense gas forms stars, SFE_dense traced by IR/HCN, depend on environment in the galaxy. The sense of the dependence is that high surface density, high molecular gas fraction regions of the galaxy show high dense gas fractions and low dense gas star formation efficiencies. This agrees with recent results for individual pointings by Usero et al. 2015 but using unbiased whole-galaxy maps. It also agrees qualitatively with the behavior observed contrasting our own Solar Neighborhood with the central regions of the Milky Way. The sense of the trends can be explained if the dense gas fraction tracks interstellar pressure but star formation occurs only in regions of high density contrast.Comment: 7 pages, 5 figures, ApJL accepte

    Biocatalytic synthesis of oxygenated biofuels through the technologies of ionic liquids and supercritical carbon dioxide

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    Póster presentado en el Congreso Nacional de Biotecnologia (BIOTEC 2019), celebrado en Vigo (España) entre los días 10 y 13 de junio de 2019.The increase in the production of biofuels has generated in the market an excess of glycerol as a byproduct. Some glycerol derivatives, such as solketal (1,2-isopropylidene glycerol), have been used successfully to synthesize new oxygenated fuels, such as fatty acid solketal esters (FASE), in order to increase the octane number of the gasolines. Biodiesel exhibits an excellent suitability as a liquid fuel (adiabatic flame temperature, viscosity, etc.), blending up to 20% volume fraction of ASE

    Factors affecting the relationship between psychological status and quality of life in COPD patients

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    <p>Abstract</p> <p>Background</p> <p>This study aims to (i) evaluate the association between anxiety and depressive symptoms and health-related quality of life (HRQoL); and (ii) identify the effect modifiers of this relationship in patients with chronic obstructive pulmonary disease (COPD).</p> <p>Methods</p> <p>A total of 337 clinically stable COPD patients answered the St. George's Respiratory Questionnaire (SGRQ) (assessing HRQoL) and the Hospital Anxiety and Depression Scale (HADS). Socio-demographic information, lung function, and other clinical data were collected.</p> <p>Results</p> <p>Most patients (93%) were male; they had a mean (SD) age of 68 (9) years and mild to very severe COPD (post-bronchodilator FEV<sub>1 </sub>52 (16)% predicted). Multivariate analyses showed that anxiety, depression, or both conditions were associated with poor HRQoL (for all SGRQ domains). The association between anxiety and total HRQoL score was 6.7 points higher (indicating a worse HRQoL) in current workers than in retired individuals. Estimates for patients with "both anxiety and depression" were 5.8 points lower in stage I-II than in stage III-IV COPD, and 10.2 points higher in patients with other comorbidities than in those with only COPD.</p> <p>Conclusions</p> <p>This study shows a significant association between anxiety, depression, or both conditions and impaired HRQoL. Clinically relevant factors affecting the magnitude of this association include work status, COPD severity, and the presence of comorbidities.</p

    Association of the microsatellite in the 3' untranslated region of the CD154 gene with rheumatoid arthritis in females from a Spanish cohort: a case-control study

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    CD40–CD154 interaction is an important mediator of inflammation and has been implicated in T helper type 1-mediated autoimmune diseases including rheumatoid arthritis (RA). Linkage studies have shown association of markers in the proximity of the CD154 gene. In the present work we investigated whether specific allele variants of the microsatellite in the 3' UTR of the CD154 gene might modulate the risk of RA. The study, in a case-control setting, included 189 patients and 150 healthy controls from the Canary Islands, Spain. The 24CAs allele was less represented in female patients than in controls (0.444 in controls versus 0.307 in patients, P = 0.006, odds ratio (OR) 0.556, 95% confidence interval (CI) 0.372 to 0.831) but not in males (0.414 versus 0.408), and only when homozygous (P = 0.012; OR 0.35, 95% CI 0.16 to 0.77). We also verified that CD154 association with RA was independent of human leukocyte antigen (HLA) phenotype. A further functional study showed that after stimulation anti-CD3, CD154 mRNA was more stable in CD4+ T lymphocytes from patients with RA bearing the 24CAs allele (mRNA half-life 208 minutes) than in patients without the 24CAs allele (109 minutes, P = 0.009). However, a lower percentage of CD154+CD4+ T lymphocytes was seen in freshly isolated peripheral blood mononuclear cells from patients carrying 24CAs alleles (mean 4.28 versus 8.12; P = 0.033), and also in CD4+ T lymphocytes stimulated with anti-CD3 (median 29.40 versus 47.60; P = 0.025). These results were concordant with the smaller amounts of CD154 mRNA isolated from stimulated T lymphocytes with 24CAs alleles. The CD154 microsatellite therefore seems to affect the expression of the gene in a complex manner that implies not only mRNA stability. These data suggest that the CD154 microsatellite contributes to the regulation of mRNA and protein expression, although further studies will be necessary to elucidate its role in disease predisposition

    Clinical role of subtraction ictal SPECT coregistered to MR Imaging and 18F-FDG PET in pediatric epilepsy

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    A precise assessment of the drug-resistant epileptic pediatric population for surgical candidacy is often challenging, and to date there are no evidence-based guidelines for presurgical identification of the epileptogenic zone. To evaluate the usefulness of radionuclide imaging techniques for presurgical evaluation of epileptic pediatric patients, we compared the results of video-electroencephalography (EEG), brain MR imaging, interictal SPECT, ictal SPECT, subtraction ictal SPECT coregistered to MR imaging (SISCOM), and interictal PET with (18)F-FDG. METHODS: Fifty-four children with drug-resistant epilepsy who had undergone video-EEG monitoring, brain MR imaging, interictal and ictal brain perfusion SPECT, SISCOM, and (18)F-FDG PET were included in this study. All abnormal findings revealed by these neuroimaging techniques were compared with the presumed location of the epileptogenic zone (PEZ) as determined by video-EEG and clinical data. The proportion of localizing studies for each technique was statistically compared. In the 18 patients who underwent resective brain surgery, neuroimaging results were compared with histopathology results and surgical outcome. RESULTS: SISCOM and (18)F-FDG PET concordance with the PEZ was significantly higher than MR imaging (P < 0.05). MR imaging showed localizing results in 21 of 54 cases (39%), SISCOM in 36 of 54 cases (67%), and (18)F-FDG PET in 31 of 54 cases (57%). If we consider SISCOM and (18)F-FDG PET results together, nuclear medicine imaging techniques showed coinciding video-EEG results in 76% of patients (41/54). In those cases in which MR imaging failed to identify any epileptogenic lesion (61% [33/54]), SISCOM or (18)F-FDG PET findings matched PEZ in 67% (22/33) of cases. CONCLUSION: SISCOM and (18)F-FDG PET provide complementary presurgical information that matched video-EEG results and clinical data in three fourths of our sample. SISCOM was particularly useful in those cases in which MR imaging findings were abnormal but no epileptogenic lesion was identified. Radionuclide imaging techniques are both useful and reliable, extending the possibility of surgical treatment to patients who may have been discouraged without a nuclear medicine approach

    The role of magnetic resonance in the evaluation of gluteoplasty: habitual aspects and complications

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    Introduction: Aesthetic procedures in the gluteal region are increasingly in evidence in recent decades with the augment in demand and the emergence of new techniques. This fact, coupled with the development and easier access to imaging methods and the increasing judicialization of medicine, makes imaging exams more frequent in patients undergoing gluteoplasty, with an emphasis currently on magnetic resonance imaging in this region. Thus, the image increasingly enters the plastic surgeon's daily clinical practice, requiring knowledge of basic concepts regarding the request and interpretation of the exams. In this article, we reviewed aspects of magnetic resonance imaging of aesthetic procedures in the gluteal region and their complications. The objective is to, through magnetic resonance studies, the usual findings in gluteoplasty procedures, as well as some of their complications, in addition to proposing an examination protocol for magnetic resonance imaging in the region. Illustrative cases of patients who underwent gluteoplasty procedures, whether approved, off-label or even illicit, were selected, in which we conducted a magnetic resonance study in our service. A bibliographic review was also done on the topic

    Degradation versus self-assembly of block copolymer micelles

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    The stability of micelles self-assembled from block copolymers can be altered by the degradation of the blocks. Slow degradation shifts the equilibrium size distribution of block copolymer micelles and change their properties. Quasi-equilibrium scaling theory shows that the degradation of hydrophobic blocks in the core of micelles destabilize the micelles reducing their size, while the degradation of hydrophilic blocks forming coronas of micelles favors larger micelles and may, at certain conditions, induce the formation of micelles from individual chains.Comment: Published in Langmuir http://pubs.acs.org/doi/pdf/10.1021/la204625

    Spectroscopic and Mechanistic Studies of Heterodimetallic Forms of Metallo-β-lactamase NDM-1

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    In an effort to characterize the roles of each metal ion in metallo-β-lactamase NDM-1, heterodimetallic analogues (CoCo-, ZnCo-, and CoCd-) of the enzyme were generated and characterized. UV–vis, 1H NMR, EPR, and EXAFS spectroscopies were used to confirm the fidelity of the metal substitutions, including the presence of a homogeneous, heterodimetallic cluster, with a single-atom bridge. This marks the first preparation of a metallo-β-lactamase selectively substituted with a paramagnetic metal ion, Co(II), either in the Zn1 (CoCd-NDM-1) or in the Zn2 site (ZnCo-NDM-1), as well as both (CoCo-NDM-1). We then used these metal-substituted forms of the enzyme to probe the reaction mechanism, using steady-state and stopped-flow kinetics, stopped-flow fluorescence, and rapid-freeze-quench EPR. Both metal sites show significant effects on the kinetic constants, and both paramagnetic variants (CoCd- and ZnCo-NDM-1) showed significant structural changes on reaction with substrate. These changes are discussed in terms of a minimal kinetic mechanism that incorporates all of the data
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