1,014 research outputs found
Mercados Informales y Control Vertical: Comercialización de Pesca Artesanal Perecible
This paper offers an in-depth case study analysis about institutional changes occurring since the late 1990s at the Chilean Austral Hake artisanal fishery. This high-value exporting fishery, specialized on selling fresh-chilled products, represents a pioneering example of self-government developments within artisanal fishermen's communities exploiting mobile marine resources in Chile. Despite entry restrictions and global catch quotas, this fishery faced a productivity crisis from the late 1980s up to the second half of the 1990s. As a response to this, fishermen initiated talks with the Government in order to introduce new management rules. After gradual evolution, today there prevails a well-developed system of de facto individual non-transferable quotas subject to a high degree of self-management by fishermen organizations. We discuss industrial organization issues which condition the exchange solutions found at this fishery. In particular, we discuss incentives derived from industrial concentration and buyer power, vertical integration and other strategies of vertical control between transacting parties at this industry; namely, between wholesale marketing brokers, exporters, processors, direct buyers of the catch and fishermen. Contractual issues of relevancy are: the use of informal markets; multi-dimensional contracting; temporal specificity due to product perishability; the use of different instruments for vertical control; and the influence of increasing degrees of industrial concentration as we advance through the wholesale commercialization channel, moving closer to the retailing stages at final export markets.Producción y comercialización de Alimentos; Cadenas de producción; Control y Coordinación Vertical; Pesca Artesanal en Chile; Merluza Austral.
Evidence for surface uplift of the Atlas Mountains and the surrounding peripheral plateaux: Combining apatite fission-track results and geomorphic indicators in the Western Moroccan Meseta (coastal Variscan Paleozoic basement)
This work represents an initial attempt to link the evolution of the topography in relation to the general tectonic framework of western Morocco. For this purpose, in a section of the Western Moroccan Meseta different tools are combined in order to attain the general objective. Apatite fission-track (AFT) data of granitic rocks of the Rabat–Khenifra area give ages around 200 Ma with track length distributions which are compatible with the thermal models already established for the area. An inverse correlation between AFT ages and elevation is observed which is compatible with previous models indicating northward tilting of the whole Western Moroccan Meseta which is younger than 20–25 Ma. In order to test this possibility a detailed analysis of the topography at different scales in the Western Moroccan Meseta has been performed. Results indicate that two open folds with different amplitudes are recognized and that the one with wider wavelength could correspond to a lithospheric fold as previously stated by other authors on the basis of independent geological arguments. The northward tilting proposed based on the AFT data agrees with the results obtained in the analysis of the topography which reinforces the presence of a very open fold with a wavelength of 200–300 km in the north-western limb of the Western Moroccan Meseta
Personalized Model to Predict Small for Gestational Age at Delivery Using Fetal Biometrics, Maternal Characteristics, and Pregnancy Biomarkers: A Retrospective Cohort Study of Births Assisted at a Spanish Hospital
Small for gestational age (SGA) is defined as a newborn with a birth weight for gestational age < 10th percentile. Routine third-trimester ultrasound screening for fetal growth assessment has detection rates (DR) from 50 to 80%. For this reason, the addition of other markers is being studied, such as maternal characteristics, biochemical values, and biophysical models, in order to create personalized combinations that can increase the predictive capacity of the ultrasound. With this purpose, this retrospective cohort study of 12,912 cases aims to compare the potential value of third-trimester screening, based on estimated weight percentile (EPW), by universal ultrasound at 35–37 weeks of gestation, with a combined model integrating maternal characteristics and biochemical markers (PAPP-A and β-HCG) for the prediction of SGA newborns. We observed that DR improved from 58.9% with the EW alone to 63.5% with the predictive model. Moreover, the AUC for the multivariate model was 0.882 (0.873–0.891 95% C.I.), showing a statistically significant difference with EPW alone (AUC 0.864 (95% C.I.: 0.854–0.873)). Although the improvements were modest, contingent detection models appear to be more sensitive than third-trimester ultrasound alone at predicting SGA at delivery
Prevalencia serológica de leucosis bovina en ganaderÃas lecheras del centro de Caldas durante 1983.
Se analizó una muestra de 670 sueros bovinos, para conocer la prevalencia de la infección por el virus de leucosis bovina (LB) en la región lechera del centro de Caldas. Por la tecnica de inmunodifusión (ID), se obtuvo una prevalencia de 14.5 por ciento en municipios de mayor explotación intensiva, movimiento de animales y localización en centros de acopio. Se encontró elevada prevalencia por fincas (49.32 por ciento) la cual afectó primordialmente a la raza Holstein (23.8 por ciento) y a los grupos de edad 2 a 3 años (17 por ciento) y de 5 a 6 años (16.7 por ciento). Se sugieren medidas de control de la infecciónGanado de leche-GanaderÃa lech
Bacterial communities involved in the nitrogen cycle in constructed wetlands
La elevada producción de agua residual y su falta de tratamiento ha llevado a la búsqueda de sistemas de depuración eficiente,
económica, fácil de operar y que permitan considerar el agua residual como un recurso. Los humedales construidos son sistemas
de tratamiento promisorios para este fin, pero la investigación de los microorganismos involucrados en la transformación de los
nutrientes en éstos es aún incipiente. En este estudio se reportan los resultados de la evaluación de poblaciones de bacterias
nitrificantes, heterotróficas y fijadoras de nitrógeno presentes en el medio de soporte, en este caso grava y columna de agua en tres
humedales construidos (HC) sometidos a distintas cargas hidráulicas y con diferentes especies vegetales: Phragmites australis,
Heliconia psittacorum y uno sin vegetación como control. El humedal con P. australis presentó mayores densidades de bacterias
nitrificantes y fijadoras de Nitrógeno (5.35 y 7.18 unidades log gr-1, respectivamente); el humedal con H. psittacorum presentó las
menores densidades para todos los grupos de bacterias y el humedal control mostró la mayor densidad de bacterias heterótrofas
(7.22 unidades log gr-1). El número de bacterias de las poblaciones encontradas, sugiere la importante actividad metabólica y
dinámica de estos microorganismos en los sistemas de humedales construidos en el trópico
Obstetric and perinatal outcomes of pregnancies with COVID 19: a systematic review and meta-analysis
Objective.
This meta-analysis aimed at comparing obstetric and perinatal outcomes in laboratory-tested pregnant women for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection before delivering.
Method.
We performed a comprehensive systematic review of electronic databases for studies reporting pregnant women with and without SARS-CoV-2 infection, as determined by polymerase chain reaction (PCR) before delivery, during the pandemic period published up to June 25, 2021. Results are reported as mean difference (MD) or odds ratio (OR) and their 95% confidence interval (CI).
Results.
Seventeen observational studies with low to moderate risk of bias, reported on 2,769 pregnant women with a positive SARS-CoV-2 PCR test and 13,807 with a negative test. Pregnant women with a positive PCR test delivered at an earlier gestational age (MD −0.19; 95% CI −0.36 to −0.02 weeks), smoked less (OR 0.75; 95% CI 0.61–0.94) and were associated with higher odds for preeclampsia (OR 1.30; 95% CI 1.09–1.54), NICU admissions (OR 2.37; 95% CI 1.18–4.76), stillbirths (OR 2.70; 95% CI, 1.38–5.29), and perinatal mortality (OR 3.23; 95% CI 1.23–8.52). There were no significant differences between positive and negative tested women in terms of nulliparity, multiple pregnancies, gestational diabetes, route of delivery, labor induction, preterm birth, infant birth weight, 5 min Apgar scores < 7, small-for-gestational-age infants and fetal malformations. Eleven studies included neonatal PCR SARS-CoV-2 testing which was performed on 129 infants, of which 20 were positive.
Conclusion.
Positive SARS-CoV-2 tested pregnant women had higher odds for preeclampsia/hypertensive disorders of pregnancy, NICU admissions, stillbirths and perinatal mortality
A new species of Trachymyrmex (Hymenoptera, Formicidae) fungus-growing ant from the Sierra Madre Oriental of northeastern Mexico
Here we describe a new species of Trachymyrmex, T. pakawa sp. n., from the Gran Sierra Plegada range of the Sierra Madre Oriental, in the states of Coahuila and Nuevo Leon, northeastern Mexico. Trachymyrmex pakawa is a large-sized species compared to other North American Trachymyrmex. Its geographic distribution includes the piedmont of the Gran Sierra Plegada at La Estanzuela, Monterrey, as well as peripheral mountains segregated from the Sierra Madre Oriental (Cerro de las Mitras, Sierra de Zapalinamé, Cañon de San Lorenzo, Cerro de las Letras). The preferred habitats of T. pakawa include oak-pine forest at La Estanzuela, xeric oak forest at Zapalinamé and mesic Chihuahuan desert scrub with sotol (Dasylirion) at other sites. All localities are on slopes, on very rocky, shallow lithosols overlaying large boulders. This species nests under and between large boulders and rocks. It has not been observed on alluvial or better developed, deeper soils, and it is absent from sites with human activity (urban, disturbed, and landscaped areas). It is closely related to and morphologically similar to Trachymyrmex smithi. The known distribution ranges of T. pakawa and T. smithi almost overlap in Saltillo, Coahuila state. The main character that distinguishes the new species from T. smithi is longer antennal scapes in T. pakawa; also, different nesting habits (rocky slopes vs. alluvial sites or deep sand in T. smithi), and geographic distribution. Phylogenetic analysis of DNA sequences from the mitochondrial marker cytochrome c oxidase subunit I (COI) and the first intron of the F1 copy of the nuclear protein-coding gene Elongation Factor 1- α (EF1-α-F1) confirm a sister-species relationship between T. pakawa and T. smithi. Bayesian coalescent analyses indicate a divergence time of about 8.00 million years before present (95% confidence interval: 4.8–11.5 mya) between T. pakawa and T. smithi. The divergence of the lineages of T. pakawa and T. smithi could have been driven by the Pliocene-Holocene desertification of southwestern North America. This process resulted in isolated mesic refugia and forests in the Madrean ranges and piedmonts of northeastern Mexico (the current habitat of T. pakawa) while T. smithi adapted to the deeper, often sandy soils on the drier desert plains of Coahuila and Chihuahua states in Mexico, and New Mexico and Texas in the USA. Within the Nearctic species of the Trachymyrmex septentrionalis species group, T. pakawa is the species that is closest (by geographical distribution) to Neotropical species of Trachymyrmex like T. saussurei
Palma de aceite Ténera Corpoica El Mira10.
El artÃculo presenta el material mejorado de palma de aceite Ténera Corpoica El Mira, en este artÃculo encontramos: el origen genético y proceso de producción, el comportamiento en la producción, el comportamiento morfológico y agronómico, el comportamiento en las plantaciones, el comportamiento frente a las enfermedades, las caracterÃsticas que identifican el material y las conclusiones.Palma-Elaeis guineensi
La palma de aceite (Elaeis guneensis J.) :proceso de obtención de materiales mejorados.
El artÃculo presenta el concepto técnico dentro del cuál encontramos las caracterÃsticas fÃsicas como Dura, PisÃfera y Tenera, la selección de Madres Dura y los componentes del fruto, la selección de Padres PisÃfera y la clasificación de las PisÃfera en Fértiles, Medianamente fértiles y estériles
Prediction of late-onset small for gestational age and fetal growth restriction by fetal biometry at 35 weeks and impact of ultrasound–delivery interval: comparison of six fetal growth standards
Small-for-gestational-age (SGA) infants have been associated with increased risk of adverse perinatal outcomes (APOs). In this work, we assess the predictive ability of the ultrasound-estimated percentile weight (EPW) at 35 weeks of gestational age to predict late-onset SGA and APOs, according to six growth standards, and whether the ultrasound–delivery interval influences the detection rate. To this purpose, we analyze a retrospective cohort study of 9585 singleton pregnancies. EPWs at 35 weeks were calculated to the customized Miguel Servet University Hospital (MSUH) and Figueras standards and the non-customized MSUH, Fetal Medicine Foundation (FMF), INTERGROWTH-21st, and WHO standards. As results of our analysis, for a 10% false positive rate, the detection rates for SGA ranged between 48.9% with the customized Figueras standard (AUC 0.82) and 60.8% with the non-customized FMF standard (AUC 0.87). Detection rates to predict SGA by ultrasound–delivery interval (1–6 weeks) show higher detection rates as intervals decrease. APOs detection rates ranged from 27.0% with FMF to 7.9% with the Figueras standard. In conclusion, the ability of EPW to predict SGA at 35 weeks is good for all standards, and slightly better for non-customized standards. The APO detection rate is significantly greater for non-customized standards
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