Sesgos en la obtención de estimas de densidad obtenidas por medio de transectos lineales en ambientes estepáricos de las Islas Canarias

We studied bias in density estimations derived from strip transects in dry open–country in the Canary Islands. We also present some critical remarks on García–del–Rey’s (2005) paper regarding strip transects and the validity of comparisons based on population densities of birds in scrublands on Tenerife island using two different methods: territory mapping and strip transect sampling. Although strip transects with census belts of 25 m do not account for detectability, this method only slightly undervalues true density estimates, and allowed to detect more than 85% of birds present in poorly vegetated environments in the Canary Islands. Previously published works on distribution and abundance of terrestrial birds in the Canary Islands using the strip transect sampling with belts of 25 m on both sides of the observer, thus provide reliable information that only slightly underestimates true densities. Key words: Birds, Canary Islands, Census methods, Strip transects, Open–country environments, Population density, Territory mapping.We studied bias in density estimations derived from strip transects in dry open–country in the Canary Islands. We also present some critical remarks on García–del–Rey’s (2005) paper regarding strip transects and the validity of comparisons based on population densities of birds in scrublands on Tenerife island using two different methods: territory mapping and strip transect sampling. Although strip transects with census belts of 25 m do not account for detectability, this method only slightly undervalues true density estimates, and allowed to detect more than 85% of birds present in poorly vegetated environments in the Canary Islands. Previously published works on distribution and abundance of terrestrial birds in the Canary Islands using the strip transect sampling with belts of 25 m on both sides of the observer, thus provide reliable information that only slightly underestimates true densities. Key words: Birds, Canary Islands, Census methods, Strip transects, Open–country environments, Population density, Territory mapping.Se estudian los sesgos derivados del empleo del método del taxiado (transectos lineales con bandas de 25 m a cada lado del observador) para obtener densidades en ambientes estepáricos de las Islas Canarias. También se presentan algunos comentarios críticos al trabajo de García–del–Rey (2005) que compara estimas de densidad obtenidas en Tenerife utilizando dos métodos diferentes: mapeo de territorios y transecto lineal. Aunque el método del taxiado estima densidades relativas no corregidas por la detectabilidad de las especies, este método proporciona valores de densidad muy parecidos a los reales, ya que permite detectar en ambientes con poca cobertura vegetal a más del 85% de los individuos dentro de bandas de 25 m a cada lado del observador. Por tanto, los trabajos previamente publicados sobre densidades de aves en Canarias proporcionan estimas fiables sólo ligeramente infravaloradas. Palabras clave: Aves, Islas Canarias, Métodos de censo, Transecto lineal, Ambientes estepáricos, Densidad de población, Mapeo de territorios

The impact of endometrioma size on ovarian responsiveness

Research question: Available evidence shows that the presence of ovarian endometriomas does not interfere with the ovarian response to ovarian stimulation. However, the mean size of the endometriomas in these studies is generally small, and two recent investigations suggested that follicular development could be impaired when focusing on larger endometriomas. However, these studies could not identify a clear threshold above which endometriomas could become detrimental. Design: To identify this threshold, the study retrospectively selected women without a history of surgery for ovarian cysts who underwent IVF in the presence of unilateral endometriomas with a mean diameter between 20 and 49 mm. Selected women were divided into three categories of endometrioma size: 20-29 mm (group 1, n = 23), 30-39 mm (group 2, n = 2323), and 40-49 mm (group 3, n = 2321). Recruitment for each category was censored at about 21 women to ensure equal statistical power for each group. Results: The response to ovarian stimulation was equal or superior in the affected gonads in eight women (35%, 95% confidence interval [CI] 16-57%), seven women (30%, 95% CI 13-53%) and two women (10%, 95% CI 2-30%) in groups 1, 2 and 3, respectively. The median (interquartile range) number of developed follicles in the affected and intact ovaries was 6 (3-7) and 5 (4-9) in group 1 (P = 0.21), 4 (1-6) and 4 (3-7) in group 2 (P = 0.08), 5 (3-7), and 7 (4-8) in group 3 (P = 0.01), respectively. Conclusions: The threshold to be used to distinguish between endometriomas that might and might not interfere with ovarian response is 4 cm in diameter

Site-to-site interdomain communication may mediate different loss-of-function mechanisms in a cancer-associated NQO1 polymorphism

Disease associated genetic variations often cause intracellular enzyme inactivation, dysregulation and instability. However, allosteric communication of mutational effects to distant functional sites leading to loss-of-function remains poorly understood. We characterize here interdomain site-to-site communication by which a common cancer-associated single nucleotide polymorphism (c.C609T/p.P187S) reduces the activity and stability in vivo of NAD(P)H:quinone oxidoreductase 1 (NQO1). NQO1 is a FAD-dependent, two-domain multifunctional stress protein acting as a Phase II enzyme, activating cancer pro-drugs and stabilizing p53 and p73a oncosuppressors. We show that p.P187S causes structural and dynamic changes communicated to functional sites far from the mutated site, affecting the FAD binding site located at the N-terminal domain (NTD) and accelerating proteasomal degradation through dynamic effects on the C-terminal domain (CTD). Structural protein:protein interaction studies reveal that the cancer-associated polymorphism does not abolish the interaction with p73a, indicating that oncosuppressor destabilization largely mirrors the low intracellular stability of p.P187S. In conclusion, we show how a single disease associated amino acid change may allosterically perturb several functional sites in an oligomeric and multidomain protein. These results have important implications for the understanding of loss-of-function genetic diseases and the identification of novel structural hot spots as targets for pharmacological intervention

Influence of STAT4 polymorphism in primary Sjögren's syndrome

Objective. To examine the influence of STAT4 rs7574865 gene polymorphism on patients with primary Sjögren's syndrome (SS). Methods. Two different cohorts were studied: 69 patients with primary SS and 296 controls from Colombia and 108 patients with primary SS and 227 controls from Germany. Samples were genotyped for the STAT4 rs7574865 single-nucleotide polymorphism with a predesigned TaqMan single-nucleotide polymorphism genotyping assay. We carried out a metaanalysis of our results combined with data published to date. Results. Although no significant differences were observed in the allele frequencies of STAT4 rs7574865 gene polymorphism between patients and controls in Colombians (p = 0.28, OR 1.24, 95% CI 0.82-1.87) and Germans (p = 0.08, OR 1.40, 95% CI 0.96-2.02), the metaanalysis disclosed a significant effect of the T allele on disease (p = 4.7 = 10-6, OR 1.40, 95% CI 1.21-1.62). Conclusion. These data reinforce the influence of STAT4 gene on primary SS and as a general autoimmune gene. The Journal of Rheumatology Copyright © 2010. All rights reserved

The muscle-relaxing C-terminal peptide from troponin I populates a nascent helix, facilitating binding to tropomyosin with a potent therapeutic effect

The conserved C-terminal end segment of troponin I (TnI) plays a critical role in regulating muscle relaxation. This function is retained in the isolated C-terminal 27 amino acid peptide (residues 184-210) of human cardiac TnI (HcTnI-C27): When added to skinned muscle fibers, HcTnI-C27 reduces the Ca2+-sensitivity of activated myofibrils and facilitates relaxation without decreasing the maximum force production. However, the underlying mechanism of HcTnI-C27 function is unknown. We studied the conformational preferences of HcTnI-C27 and a myopathic mutant, Arg192His, (HcTnI-C27-H). Both peptides were mainly disordered in aqueous solution with a nascent helix involving residues from Trp191 to Ile195, as shown by NMR analysis and molecular dynamics simulations. The population of nascent helix was smaller in HcTnIC27-H than in HcTnI-C27, as shown by circular dichroism (CD) titrations. Fluorescence and isothermal titration calorimetry (ITC) showed that both peptides bound tropomyosin (aTm), with a detectably higher affinity (~10 µM) of HcTnIC27 than that of HcTnI-C27-H (~15 µM), consistent with an impaired Ca2+-desensitization effect of the mutant peptide on skinned muscle strips. Upon binding to aTm, HcTnI-C27 acquired a weakly stable helix-like conformation involving residues near Trp191, as shown by transferred nuclear Overhauser effect spectroscopy and hydrogen/deuterium exchange experiments. With the potent Ca2+-desensitization effect of HcTnI-C27 on skinned cardiac muscle from a mouse model of hypertrophic cardiomyopathy, the data support that the C-terminal end domain of TnI can function as an isolated peptide with the intrinsic capacity of binding tropomyosin, providing a promising therapeutic approach to selectively improve diastolic function of the heart

Cobalt Metal-Organic Framework based on two dinuclear secondary building units for electrocatalytic oxygen evolution

The synthesis of a new microporous metal-organic framework (MOF) based on two secondary building units, with dinuclear cobalt centers, has been developed. The employment of a well-defined cobalt cluster results in an unusual topology of the Co2-MOF, where one of the cobalt centers has three open coordination positions, which has no precedent in MOF materials based on cobalt. Adsorption isotherms have revealed that Co2-MOF is in the range of best CO2 adsorbents among the carbon materials, with very high CO2/CH4 selectivity. On the other hand, dispersion of Co2-MOF in an alcoholic solution of Nafion gives rise to a composite (Co2-MOF@Nafion) with great resistance to hydrolysis in aqueous media and good adherence to graphite electrodes. In fact, it exhibits high electrocatalytic activity and robustness for the oxygen evolution reaction (OER), with a turnover frequency number value superior to those reported for similar electrocatalysts. Overall, this work has provided the basis for the rational design of new cobalt OER catalysts and related materials employing well-defined metal clusters as directing agents of the MOF structure

Gamma Ray Bursts: Observations and Theoretical Conjectures

Gamma Ray Bursts (GRBs) are short bursts of very high energy photons which were discovered in the late 1960s. Ever since their discovery, scientists have wondered about their origin. Nowadays it is known that they originate outside the Milky Way because of their high red shift rst measured in the afterglows thanks to the Beppo-SAX satellite and ground-based observations. However, theoreticians still do not agree about the mechanism that generates the bursts, and different competing models are animatedly debated. Current GRB experiments include the Swift satellite and the Pierre Auger Observatory that could detect GRBs with an increase of the background. A forthcoming dedicated experiment is GLAST, a satellite observatory for detecting gamma rays with energies up to 300 GeV, whose launch is scheduled for early 2008

Manejo no tecnificado de cerdos (Sus scrofa) en las regiones Andina, Amazónica y Orinoquía de Colombia

The swine industry in Colombia has grown in recent years. A percentage of this industry occurs under technified conditions. However, in several regions of the country, there are small artisanal pig production systems where management exhibits a gradient in animal husbandry from confinement to complete freedom with different health implications. The aim of this study was to identify the most common non-technified forms of pig farming in several regions of Colombia and to explore their implications. Data collection was carried out in the flooded savannas of the Colombian Orinoquia region and through the Classical Swine Fever (CSF) eradication zone, as well as in the Guaviare department. The information was gathered from semi-structured interviews with public officials and local settlers involved in pig farming. The work was carried out in August 2017 and from June to October 2019. In total, the work included a distance of 8,486.4 km along 151 municipalities of the country, and 262 semi-structured interviews were conducted. The following four types of pig farming management were identified: confined, outdoor enclosure, free breeding, and feral or unmanaged breeding. Each management type reflects differences in the need for care, economic investment, escape risk, or pig release frequency, facilitating feral behavior. Furthermore, information on health aspects, food, reproduction, and institutional presence in each municipality as well as on current problems faced by producers for slaughtering and commercialization of pigs was obtained.La industria porcina en Colombia ha crecido en los últimos años. Aunque parte de esta actividad se realiza en instalaciones tecnificadas, en varias regiones del país aún existen pequeños sistemas de producción artesanales, cuyas condiciones de manejo de los animales varían desde tenerlos confinados hasta completamente libres, con diferentes implicaciones sanitarias. Este estudio buscó identificar las formas no tecnificadas más comunes para la cría de cerdos en varias regiones de Colombia y explorar sus implicaciones. Se recolectaron datos de las sabanas inundables de la Orinoquía colombiana, la zona en erradicación de la peste porcina clásica y el departamento del Guaviare. La información fue recopilada mediante entrevistas semiestructuradas a funcionarios públicos y pobladores locales involucrados en la cría de cerdos. El trabajo se realizó en agosto de 2017 y entre junio y octubre de 2019. En total, se recorrieron 8.486,4 km en 151 municipios del país, y se realizaron 262 entrevistas semiestructuradas. Se identificaron cuatro tipos de manejo para la cría de cerdos: en cochera, en encierro, cría libre y asilvestrada (sin manejo). Cada tipo de manejo refleja diferentes necesidades de cuidado, inversión económica, riesgo de escape o frecuencia de liberación de los cerdos, lo que facilita el asilvestramiento. Además, se obtuvo información sobre las condiciones sanitarias, la alimentación, la reproducción, la presencia institucional en cada municipio y la dificultad de los pequeños productores para el sacrificio y la comercialización