1,621 research outputs found

    Location of Decimetric Pulsations in Solar Flares

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    This work investigates the spatial relation between coronal X-ray sources and coherent radio emissions, both generally thought to be signatures of particle acceleration. Two limb events were selected during which the radio emission was well correlated in time with hard X-rays. The radio emissions were of the type of decimetric pulsations as determined from the spectrogram observed by Phoenix-2 of ETH Zurich. The radio positions were measured from observations with the Nançay Radioheliograph between 236 and 432 MHz and compared to the position of the coronal X-ray source imaged with RHESSI. The radio pulsations originated at least 30 - 240Mm above the coronal hard X-ray source. The altitude of the radio emission increases generally with lower frequency. The average positions at different frequencies are on a line pointing approximately to the coronal hard X-ray source. Thus, the pulsations cannot be caused by electrons trapped in the flare loops, but are consistent with emission from a current sheet above the coronal sourc

    Cría y manejo del cachorro del lobo ibérico (Canis lupus signatus)

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    El lobo ibérico (Canis lupus signatus) es un cánido salvaje bien representado en parques zoológicos en cautividad. Este trabajo expone los protocolos de actuación para un correcto manejo del neonato de lobo durante la lactancia artificial, así como para el destete y su medicina preventiva (vacunación y desparasitación). También se tendrá en cuenta las influencias del factor humano en su desarrollo y las patologías más frecuentes que se pueden presentar en el lobo ibérico en esta edad. Para este trabajo se emplearon diferentes tetinas dependiendo de la edad de los animales. Se utilizaron leches artificiales de cánido doméstico durante el tiempo de lactancia y carne de diferente origen para su destete. Las vacunas usadas para llevar a cabo el protocolo de medicina preventiva propuesto fueron vacunas comerciales de cánidos domésticos. Los cachorros de este trabajo adquirieron tras seis meses las características fisiológicas en cuanto a peso, tamaño, etc. esperadas. Los protocolos propuestos en este trabajo son considerados válidos para la crianza del cachorro del lobo ibérico en cautividad.The Iberian wolf (Canis lupus signatus)is a wild animal well represented in zoological parks. This work exposes the performance protocols for a correct managing of the newborn of wolf during the artificial lactation, as well as for wean and his preventive medicine (vaccination and worm). Also take into account the influences of the human factor in their development and the most frequent pathologies than can be presented in the Iberian wolf in this age. In this work we employ different teat, depending on the age on the animals. We used artificial milk of domestic dog during the lactation and meat of different origin for there wean. The vaccines used to carry out the proposed preventive medicine protocol were commercial vaccines of domestic dog. The cubs of this work acquired, after six months, the physiological characteristics; weight, size, etc. waited. The protocols proposed in this work were considered valid for the breed of the cub of Iberian wolf in zoological parks

    Cytochrome P450-catalyzed insertion of carbenoids into N–H bonds

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    Expanding nature’s catalytic repertoire to include reactions important in synthetic chemistry will open new opportunities for ‘green’ chemistry and biosynthesis. We demonstrate the first enzyme-catalyzed insertion of carbenoids into N–H bonds. This type of bond disconnection, which has no counterpart in nature, can be mediated by variants of the cytochrome P450 from Bacillus megaterium. The N–H insertion reaction takes place in water, provides the desired products in 26–83% yield, forms the single addition product exclusively, and does not require slow addition of the diazo component

    New Perspectives on Ecological Mechanisms Affecting Coral Recruitment on Reefs

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    Coral mortality has increased in recent decades, making coral recruitment more important than ever in sustaining coral reef ecosystems and contributing to their resilience. This review summarizes existing information on ecological factors affecting scleractinian coral recruitment. Successful recruitment requires the survival of coral offspring through sequential life history stages. Larval availability, successful settlement, and post-settlement survival and growth are all necessary for the addition of new coral individuals to a reef and ultimately maintenance or recovery of coral reef ecosystems. As environmental conditions continue to become more hostile to corals on a global scale, further research on fertilization ecology, connectivity, larval condition, positive and negative cues influencing substrate selection, and post-settlement ecology will be critical to our ability to manage these diverse ecosystems for recovery. A better understanding of the ecological factors infl uencing coral recruitment is fundamental to coral reef ecology and management

    Hot topics, urgent priorities, and ensuring success for racial/ethnic minority young investigators in academic pediatrics.

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    BackgroundThe number of racial/ethnic minority children will exceed the number of white children in the USA by 2018. Although 38% of Americans are minorities, only 12% of pediatricians, 5% of medical-school faculty, and 3% of medical-school professors are minorities. Furthermore, only 5% of all R01 applications for National Institutes of Health grants are from African-American, Latino, and American Indian investigators. Prompted by the persistent lack of diversity in the pediatric and biomedical research workforces, the Academic Pediatric Association Research in Academic Pediatrics Initiative on Diversity (RAPID) was initiated in 2012. RAPID targets applicants who are members of an underrepresented minority group (URM), disabled, or from a socially, culturally, economically, or educationally disadvantaged background. The program, which consists of both a research project and career and leadership development activities, includes an annual career-development and leadership conference which is open to any resident, fellow, or junior faculty member from an URM, disabled, or disadvantaged background who is interested in a career in academic general pediatrics.MethodsAs part of the annual RAPID conference, a Hot Topic Session is held in which the young investigators spend several hours developing a list of hot topics on the most useful faculty and career-development issues. These hot topics are then posed in the form of six "burning questions" to the RAPID National Advisory Committee (comprised of accomplished, nationally recognized senior investigators who are seasoned mentors), the RAPID Director and Co-Director, and the keynote speaker.Results/conclusionsThe six compelling questions posed by the 10 young investigators-along with the responses of the senior conference leadership-provide a unique resource and "survival guide" for ensuring the academic success and optimal career development of young investigators in academic pediatrics from diverse backgrounds. A rich conversation ensued on the topics addressed, consisting of negotiating for protected research time, career trajectories as academic institutions move away from an emphasis on tenure-track positions, how "non-academic" products fit into career development, racism and discrimination in academic medicine and how to address them, coping with isolation as a minority faculty member, and how best to mentor the next generation of academic physicians

    Suicide Risk and School Related Stressors in Veterinary Students

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    Compared to the general population of the United States, veterinarians are at an increasingly higher risk for suicide. This is commonly associated with stressful work environments, long work hours, poor work-life balance, client demands and complaints, and large amounts of euthanasia procedures. While many studies have been performed to confirm the above statements, few to no studies have been done on students currently enrolled in veterinary school to assess their mental health. This study will survey graduate school students in this field and will evaluate their mental health state and risk factors towards suicide. Through comparing the results of this survey to previous studies on the mental health and suicide risk of licensed veterinarians, I am hoping to pinpoint when the increased risk starts. By pinpointing the trend beginning, programs will be able to target help and treatment options better suited for decreasing the rate of suicide among individuals in the field of veterinary medicine

    Improved Cyclopropanation Activity of Histidine-Ligated Cytochrome P450 Enables the Enantioselective Formal Synthesis of Levomilnacipran

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    Engineering enzymes capable of modes of activation unprecedented in nature will increase the range of industrially important molecules that can be synthesized through biocatalysis. However, low activity for a new function is often a limitation in adopting enzymes for preparative-scale synthesis, reaction with demanding substrates, or when a natural substrate is also present. By mutating the proximal ligand and other key active-site residues of the cytochrome P450 enzyme from Bacillus megaterium (P450-BM3), a highly active His-ligated variant of P450-BM3 that can be employed for the enantioselective synthesis of the levomilnacipran core was engineered. This enzyme, BM3-Hstar, catalyzes the cyclopropanation of N,N-diethyl-2-phenylacrylamide with an estimated initial rate of over 1000 turnovers per minute and can be used under aerobic conditions. Cyclopropanation activity is highly dependent on the electronic properties of the P450 proximal ligand, which can be used to tune this non-natural enzyme activity

    Sulfur K-Edge XAS Studies of the Effect of DNA Binding on the [Fe_4S_4] Site in EndoIII and MutY

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    S K-edge X-ray absorption spectroscopy (XAS) was used to study the [Fe_4S_4] clusters in the DNA repair glycosylases EndoIII and MutY to evaluate the effects of DNA binding and solvation on Fe–S bond covalencies (i.e., the amount of S 3p character mixed into the Fe 3d valence orbitals). Increased covalencies in both iron–thiolate and iron–sulfide bonds would stabilize the oxidized state of the [Fe_4S_4] clusters. The results are compared to those on previously studied [Fe_4S_4] model complexes, ferredoxin (Fd), and to new data on high-potential iron–sulfur protein (HiPIP). A limited decrease in covalency is observed upon removal of solvent water from EndoIII and MutY, opposite to the significant increase observed for Fd, where the [Fe_4S_4] cluster is solvent exposed. Importantly, in EndoIII and MutY, a large increase in covalency is observed upon DNA binding, which is due to the effect of its negative charge on the iron–sulfur bonds. In EndoIII, this change in covalency can be quantified and makes a significant contribution to the observed decrease in reduction potential found experimentally in DNA repair proteins, enabling their HiPIP-like redox behavior

    Prevalence of renal impairment and its association with cardiovascular risk factors in a general population: results of the Swiss SAPALDIA study

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    Background. Impaired renal function is evolving as an independent marker of the risk of cardiovascular morbidity and mortality. Little is known about the prevalence of impaired renal function and its relationship to cardiovascular risk factors in the Swiss general population. Methods. SAPALDIA comprises a random sample of the Swiss population established in 1991, originally to investigate the health effects of long-term exposure to air pollution. Participants were reassessed in 2002/3 and blood measurements were obtained (n = 6317). Renal function was estimated using the Cockcroft-Gault equation and the modified MDRD (four-component) equation incorporating age, race, gender and serum creatinine level. Results. The estimated prevalence of impaired renal function [estimated glomerular filtration rate <60 ml/min/1.73 m2] differed substantially between men and women, particularly at higher ages, and amounted to 13% [95% confidence interval (CI) 10-16%] and 36% (95% CI 32-40%) in men and women, respectively, of 65 years or older. Smoking, obesity, blood lipid levels, high systolic blood pressure and hyperuricaemia were all more common in men when compared with women. These cardiovascular risk factors were also associated independently with creatinine in both women and men. Women were less likely to receive cardiovascular drugs, in particular angiotensin-converting enzyme inhibitors and β-blockers, when compared with men of the same age. Conclusion. Moderate renal impairment seems to be prevalent in the general population, with an apparent excess in females which is not explained by conventional cardiovascular risk factors. The unexpected finding questions the validity of the prediction equations, in particular in female
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