4,365 research outputs found
Creatividad ante la adversidad: La agricultura de las mujeres de Cayambe
La agricultura familiar genera más del 45 % de los alimentos que llegan a nuestros centros urbanos. Este modelo de producción demanda de políticas dinámicas para el impulso productivo, acceso a recursos, información, tecnología y crédito. En este escenario las decisiones de explotación priorizan el abastecimiento de alimentos para autoconsumo sobre los ingresos por comercialización. En este sentido, el presente trabajo realiza un análisis del modelo agrícola propuesto por la Red de mujeres productoras de BIOVIDA frente a la falta de incentivos que capitalicen las explotaciones y mejoren las líneas de comercialización directa. El trabajo recoge algunos testimonios que se complementan con la información obtenida para evaluar el bienestar familiar y el desarrollo productivo. De esta forma, se observa como la Red constituye una estructura social-productiva, mejorando los ingresos y el acceso a mejores alimentos para el consumo familiar
Identification of evidence by engineering undergraduates and pre-service science teachers in an argumentation activity
Scientific argumentation is considered as one of the general competencies that engineering students must achieve. This paper analyses the capacity to identify evidence in an argumentation activity on characteristics of materials, developed with 46 engineering undergraduates of the second year of the Degree in Industrial Technologies Engineering and 81 pre-service science teachers of the University of Malaga (Malaga, Spain). These pre-service science teachers studied a Master's Degree in Secondary Education and were classified for this study in two groups depending on whether or not their previous degree was related to the knowledge necessary to solve the activity. The activity proposes to argue the choice of a bicycle according to the material of manufacture (steel or aluminium), focusing this paper on the analysis of the evidence shown in their arguments. A number of evidence, their type, their quality in terms of the level of adequacy and precision, and the inclusion or not of personal ideas, were considered as dimensions. The results show that engineering undergraduates are capable of offering arguments with a greater number of evidence and of different types (economic, physical-chemical and mechanical) as opposed to pre-service science teachers. On the contrary, pre-service teachers offer arguments with a better quality of evidence than undergraduates. Pre-service science teachers from degrees unrelated to the activity used a great number of personal ideas when arguing. These results highlight the need to continue training both undergraduates and pre-service teachers so that they can argue in their profession in the best possible way.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
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Infectious Syphilis in Non-Hispanic Blacks and Hispanics in an Urban STD Clinic
Syphilis is a complex infectious disease caused by Treponema pallidum and acquired through sexual contact or vertical transmission. The natural history of syphilis is divided in primary, secondary, latent and tertiary stages. The syphilis epidemic has evolved over the years. National rates of syphilis infection dropped to the lowest in 2000 and have since increased in certain populations. Men who have sex with men (MSM) account for 60% of new infections and high rates occur in individuals with human immune deficiency virus co-infection. This study describes and compares the demographic characteristics, risk factors, and clinical presentation ofinfectious syphilis cases diagnosed in the Miami-Dade Health Department STD clinic among the two main ethnicities (non-Hispanic Black and Hispanic)
Groundwater protection using vulnerability maps and wellhead protection area (WHPA). A case study in México
The need to protect groundwater resources against quality deterioration due to anthropogenic activities is unquestionable. The concept of aquifer pollution vulnerability maps and of wellhead protection areas (WHPA) as protection toolsis not new; however, in spite of the elapsed time, their use has been increased as a result of the increase in economic development—and everything that this entails—and the increase in prohibitive costs of treating contaminated water or of the decontamination of aquifers. The study’s objective was to establish an integrated method that defines, first of all, the areas of highest vulnerability in the aquifer, and second, within these areas, the wells that most urgently need protection. To identify these wells, additional criteria were taken, such as well constructive data, pumped volume, and the region’s socioeconomic characteristics (social exclusión index). Once the wells were ranked, several of them were chosen as a pilot study to compare different methods for the delineation of WHPA based on calculated fixed radius and analytical methods and, this way, identify which method or methods best adapt to the characteristics of the study area. The Minkin analytical method proved to offer the best results since it protects well on both sides and achieves a balance in the well’s upgradient distances. It is also worth mentioning that the delimitation of the WHPAs in the study area was limited in respect to hydrogeologic and technical data
Transcriptional And Molecular Pathways Activated In Mesenteric Adipose Tissue And Intestinal Mucosa Of Crohn's Disease Patients
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Crohn's disease (CD) is a chronic inflammatory disorder, characterized by cytokine imbalance and transcription signaling pathways activation. In addition, the increase of mesenteric adipose tissue (MAT) near the affected intestinal area is a hallmark of CD. Therefore, we evaluated the transcription signaling pathways and cytokines expression in intestinal mucosa and MAT of active CD patients. Ten patients with ileocecal CD and eight with noninflammatory diseases were studied. The biopsies of intestinal mucosa and MAT were snap-frozen and protein expression was determined by immunoblotting. RNA levels were measured by qPCR. The pIkB/IkB ratio and TNF alpha level were significantly higher in intestinal mucosa of CD when compared to controls. However, STAT1 expression was similar between intestinal mucosa of CD and controls. Considering the MAT, the pIkB/IkB ratio was significantly lower and the anti-inflammatory cytokine ILl0 was significantly higher in CD when compared to controls. Finally, the protein content of pSTAT1 was higher in MAT of CD compared to controls. These findings reinforce the predominance of the proinflammatory NF-kB pathway in CD intestinal mucosa. For the first time, we showed the activation of STATI pathway in MAT of CD patients, which may help to understand the physiopathology of this immune mediated disease.FAPESP (Fundacao de Amparo a Pesquisa do Estado de Sao Paulo)FAEPEX (Fundo de Apoio ao Ensino, a Pesquisa e Extensao)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP
Cohesive-frictional model for bond and splitting action of prestressing wire
This paper presents a numerical procedure for bond between indented wires and concrete, and the coupled splitting process of the surrounding concrete. The bond model is an interface, non-associative, plasticity model. It is coupled with a cohesive fracture model for concrete to take into account the splitting of such concrete. Bond between steel and concrete is fundamental for the transmission of stresses between both materials in precast prestressed concrete. Indented wires are used to improve the bond in these structural elements. The radial component of the prestressing force, increased by Poisson's effect, may split the surrounding concrete, decreasing the wire confinement and diminishing the bonding. The combined action of the bond and the splitting is studied with the proposed model. The results of the numerical model are compared with the results of a series of tests, such as those which showed splitting induced by the bond between wire and concrete. Tests with different steel indentation depths were performed. The numerical procedure accurately reproduces the experimental records and improves knowledge of this complex proces
Thermoelectric Properties of N-Type Poly (Ether Ether Ketone)/Carbon Nanofiber Melt-Processed Composites
The thermoelectric properties, at temperatures from 30 °C to 100 °C, of melt-processed poly(ether ether ketone) (PEEK) composites prepared with 10 wt.% of carbon nanofibers (CNFs) are discussed in this work. At 30 °C, the PEEK/CNF composites show an electrical conductivity (σ) of ~27 S m−1 and a Seebeck coefficient (S) of −3.4 μV K−1, which means that their majority charge carriers are electrons. The origin of this negative Seebeck is deduced because of the impurities present in the as-received CNFs, which may cause sharply varying and localized states at approximately 0.086 eV above the Fermi energy level (EF) of CNFs. Moreover, the lower S, in absolute value, found in PEEK/CNF composites, when compared with the S of as-received CNFs (−5.3 μV K−1), is attributed to a slight electron withdrawing from the external layers of CNFs by the PEEK matrix. At temperatures from 30 °C to 100 °C, the σ (T) of PEEK/CNF composites, in contrast to the σ (T) of as-received CNFs, shows a negative temperature effect, understood through the 3D variable-range hopping (VRH) model, as a thermally activated hopping mechanism across a random network of potential wells. Moreover, their nonlinear S (T) follows the same behavior reported before for polypropylene composites melt-processed with similar CNFs at the same interval of temperatures
Factors Associated With Red Blood Cell Transfusions In Very-low-birth-weight Preterm Infants In Brazilian Neonatal Units
Background: Preterm infants in neonatal intensive care units frequently receive red blood cells (RBC) transfusions due to the anemia of prematurity. A number of variables related to gestational age, severity of illness and transfusion practices adopted in the neonatal unit where the neonate was born may contribute to the prescription of RBC transfusions. This study aimed to analyse the frequency and factors associated with RBC transfusions in very-low-birth-weight preterm infants. Methods: A prospective cohort of 4283 preterm infants (gestational age: 29.9 +/- 2.9 weeks; birth weight: 1084 +/- 275 g) carried out at 16 university hospitals in Brazil between January 2009 and December 2011 was analysed. Factors associated with RBC transfusions were evaluated using univariate and multiple logistic regression analysis. Results: A total of 2208 (51.6 %) infants received RBC transfusions (variation per neonatal unit: 34.1 % to 66.4 %). RBC transfusions were significantly associated with gestational age (OR: -1.098; 95% CI: -1.12 to -1.04), SNAPPE II score (1.01; 1.00-1.02), apnea (1.69; 1.34-2.14), pulmonary hemorrhage (2.65; 1.74-4.031), need for oxygen at 28 days of life (1.56; 1.17-2.08), clinical sepsis (3.22; 2.55-4.05), necrotising enterocolitis (3.80; 2.26-6.41), grades III/IV intraventricular hemorrhage (1.64; 1.05-2.58), mechanical ventilation (2.27; 1.74-2.97), use of umbilical catheter (1.86; 1.35-2.57), parenteral nutrition (2.06; 1.27-3.33), > 60 days of hospitalization (5.29; 4.02-6.95) and the neonatal unit where the neonate was born. Conclusions: The frequency of RBC transfusions varied among neonatal intensive care units. Even after adjusting for adverse health conditions and therapeutic interventions, the neonatal unit continued to influence transfusion practices in very-low birth-weight infants.1
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