4,059 research outputs found

    Homozygous in-frame deletion in CATSPERE in a man producing spermatozoa with loss of CatSper function and compromised fertilizing capacity

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    STUDY QUESTIONDoes a man (patient 1) with a previously described deficiency in principle cation channel of sperm (CatSper) function have a mutation in the CatSper-epsilon (CATSPERE) and/or CatSper-zeta (CATSPERZ) gene?SUMMARY ANSWERPatient 1 has a homozygous in-frame 6-bp deletion in exon 18 (c.2393_2398delCTATGG, rs761237686) of CATSPERE.WHAT IS KNOWN ALREADYCatSper is the principal calcium channel of mammalian spermatozoa. Spermatozoa from patient 1 had a specific loss of CatSper function and were unable to fertilize at IVF. Loss of CatSper function could not be attributed to genetic abnormalities in coding regions of seven CatSper subunits. Two additional subunits (CatSper-epsilon (CATPSERE) and CatSper-zeta (CATSPERZ)) were recently identified, and are now proposed to contribute to the formation of the mature channel complex.STUDY DESIGN, SIZE, DURATIONThis was a basic medical research study analysing genomic data from a single patient (patient 1) for defects in CATSPERE and CATSPERZ.PARTICIPANTS/MATERIALS, SETTING, METHODSThe original exome sequencing data for patient 1 were analysed for mutations in CATSPERE and CATSPERZ. Sanger sequencing was conducted to confirm the presence of a rare variant.MAIN RESULTS AND THE ROLE OF CHANCEPatient 1 is homozygous for an in-frame 6-bp deletion in exon 18 (c.2393_2398delCTATGG, rs761237686) of CATSPERE that is predicted to be highly deleterious.LIMITATIONS, REASONS FOR CAUTIONThe nature of the molecular deficit caused by the rs761237686 variant and whether it is exclusively responsible for the loss of CatSper function remain to be elucidated.WIDER IMPLICATIONS OF THE FINDINGSPopulation genetics are available for a significant number of predicted deleterious variants of CatSper subunits. The consequence of homozygous and compound heterozygous forms on sperm fertilization potential could be significant. Selective targeting of CatSper subunit expression maybe a feasible strategy for the development of novel contraceptives.STUDY FUNDING/COMPETING INTEREST(S)This study was funded by project grants from the MRC (MR/K013343/1 and MR/012492/1), Chief Scientist Office/NHS research Scotland. This work was also supported by NIH R01GM111802, Pew Biomedical Scholars Award 00028642 and Packer Wentz Endowment Will to P.V.L. C.L.R.B is the editor-in-chief of Molecular Human Reproduction, has received lecturing fees from Merck and Ferring, and is on the Scientific Advisory Panel for Ohana BioSciences. C.L.R.B was chair of the World Health Organization Expert Synthesis Group on Diagnosis of Male infertility (2012–2016)

    Water Replenishment in Agricultural Soils: Dissemination of the IrrigaPot Technology

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    The challenge confronted by farmers during prolonged periods of soil water stress is to guarantee the restoration of water and maintain the productivity of agricultural crops. Even in regions such as Amazon, the variability in the precipitation regime should be considered in agricultural planning. There are regions in which 80% of annual rainfall is concentrated between December and June. It is exactly during this period of low rainfall that small-scale family-based farmers need technological assistance to guarantee that their crops remain irrigated in order to maintain their income in this rural environment. The IrrigaPot arises as an alternative that is able to access rainfall that has been stored since the rainy season and provide it to plants when the soil is dry. The pots are maintained full with 20 liters of water, and through capillary action the soil maintains them constantly humid. This technology does not require specific knowledge with respect to irrigation regimes and is necessary for the farmer to dedicate his time to replacing water. The technology is totally automated through a simple system using a float, tubes, and connectors that connect a rubber hose to the lids of the pots buried in the soil

    O OLHAR ECOLÓGICO:: Contribuições para mudanças de paradigma na ciência e na educação.

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    A questão ambiental, cada vez mais, apresenta-se como um elemento importante para se refletir sobre as condições atuais do desenvolvimento econômico e dos discursos que este produz. A ciência, assim como a educação, neste contexto, aparecem como campos importantes na construção de conhecimento e cultura, e consequentemente na maneira como as políticas públicas lidam com esta produção de saber, portanto, procuramos problematizar alguns aspectos da metodologia corrente, introduzindo a temática dainterdisciplinaridade, do pensamento complexo, da visão sistêmica de mundo, destacando a importância do exercício da autocrítica. Estes componentes, essenciais para a Filosofia Ecológica, favorecem o debate sobre as relações que se estabelecem entre diferentes organismos e o meio ambiente, e nos permite vislumbrar alternativas criativas e coerentes ao se observar e interpretar o mundo, buscando formas modo menos destrutivo de produção, tanto material quanto simbólica, em relação a natureza.

    Performance of Beef Cattle Fed Diets Containing \u3cem\u3eStylosanthes\u3c/em\u3e and Corn Silages

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    Reports of the use of tropical legumes in silage production are scarce as these legumes have high contents of crude protein, low water soluble carbohydrate and high buffering capacity, which inhibit the production of silages with good fermentation and nutritional characteristics. Recent research has, however, shown that it is possible to produce good quality silages using tropical legumes (Pereira et al. 2012). Souza et al. (2012) concluded that silage produced from Stylosanthes cv. Campo Grande (Stylosanthes capitata + Stylosanthes macrocephala) at 60% proportion of the dry matter of the diet can replace corn silage in diets for beef cattle in feedlots without altering their intake and productive performance. However, the ideal proportion of this silage in the diets for beef cattle is still unknown. Thus, the objective of this study was to evaluate the intake and performance of beef cattle fed diets with Stylosanthes and corn silages

    Dark spinor models in gravitation and cosmology

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    We introduce and carefully define an entire class of field theories based on non-standard spinors. Their dominant interaction is via the gravitational field which makes them naturally dark; we refer to them as Dark Spinors. We provide a critical analysis of previous proposals for dark spinors noting that they violate Lorentz invariance. As a working assumption we restrict our analysis to non-standard spinors which preserve Lorentz invariance, whilst being non-local and explicitly construct such a theory. We construct the complete energy-momentum tensor and derive its components explicitly by assuming a specific projection operator. It is natural to next consider dark spinors in a cosmological setting. We find various interesting solutions where the spinor field leads to slow roll and fast roll de Sitter solutions. We also analyse models where the spinor is coupled conformally to gravity, and consider the perturbations and stability of the spinor.Comment: 43 pages. Several new sections and details added. JHEP in prin

    Desenvolvimento de um potenciostato de baixo custo para ser empregado em aulas experimentais de Eletroquímica / Development of a low cost potentiostat to be used in experimental classes of Electrochemistry

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    As atividades experimentais são apontadas como uma importante ferramenta para auxiliar na construção do conhecimento científico durante a formação discente. No entanto, muitas vezes, por falta de reagentes e equipamentos adequados, tais atividades são pouco exploradas nas escolas. Diante disso, este artigo relata a produção de um potenciostato de baixo custo realizada por alunos do curso Técnico Integrado em Mecatrônica do Instituto Federal de Santa Catarina (IFSC – Câmpus Criciúma). O potenciostato é um dispositivo que pode ser utilizado na determinação qualitativa e quantitativa de diferentes espécies químicas através da aplicação de potencial/corrente. Medidas de voltametria cíclica foram realizadas para testar o desempenho do protótipo desenvolvido. Os resultados obtidos apontaram que o potenciostato proposto pode ser satisfatoriamente utilizado em aulas experimentais de Eletroquímica. O custo final do protótipo foi de aproximadamente 230,00 reais, valor muito abaixo de um equipamento comercializado

    Statistical analysis of the onset temperature of solar flares in 2010-2011

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    Understanding the physical processes that trigger solar flares is paramount to help with forecasting space weather and mitigating the effects on our technological infrastructure. A previously unknown phenomenon was recently identified in solar flares: the plasma temperature, derived from soft X-ray (SXR) data, at the onset of four flares, was revealed to be in the range 10-15 MK, without evidence of gradual heating. To investigate how common the hot-onset phenomenon may be, we extend this investigation to solar flares of B1.2- X6.9 classes recorded by the X-ray Sensor (XRS) on-board the GOES-14 and GOES-15 satellites between 2010 and 2011. For this statistical study, we employed the same methodology as in recent work, where the pre-flare SXR flux of each flare is obtained manually, and the temperature and emission measure values are obtained by the flux ratio of the two GOES/XRS channels using the standard software. From 3224 events listed in the GOES flare catalog for 2010-2011, we have selected and analyzed 745 events for which the flare heliographic location was provided in the list, to investigate center-to-limb effects of the hot-onset phenomenon. Our results show that 559 out of 745 flares (75%) exhibit an onset temperature above 8.6 MK (the first quartile), with respective log10 of the emission measure values between 46.0 - 47.25 cm-3, indicating that small amounts of plasma are quickly heated to high temperatures. These results suggest that the hot-onset phenomenon is very common in solar flares.Comment: 6 pages,7 figure

    Origin of anomalously long interatomic distances in suspended gold chains

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    The discovery of long bonds in gold atom chains has represented a challenge for physical interpretation. In fact, interatomic distances frequently attain 3.0-3.6 A values and, distances as large as 5.0 A may be seldom observed. Here, we studied gold chains by transmission electron microscopy and performed theoretical calculations using cluster ab initio density functional formalism. We show that the insertion of two carbon atoms is required to account for the longest bonds, while distances above 3 A may be due to a mixture of clean and one C atom contaminated bonds.Comment: 4 pages, 4 Postscript figures, to be published in Physical Review Letter
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