624 research outputs found
Five new species of the genera Heerz Marsh, Lissopsius Marsh and Ondigus Braet, Barbalho and van Achterberg (Braconidae, Doryctinae) from the Chamela-Cuixmala biosphere reserve in Jalisco, Mexico
Five new species belonging to the poorly known Neotropical doryctine parasitoid wasps genera Heerz Marsh (H. ecmahla sp. n. and H. macrophthalma sp. n.), Lissopsius Marsh (L. pacificus sp. n. and L. jalisciensis sp. n.) and Ondigus Braet, Barbalho & van Achterberg (O. cuixmalensis sp. n.) are described from the Chamela-Cuixmala Biosphere reserve in Jalisco, Mexico. Keys to the described species of the above three genera are provided. The phylogenetic placement of the examined taxa is investigated based on mitochondrial (COI) and nuclear (28S, 2nd and 3rd domain regions) DNA sequence data.Fil: Zaldivar Riverón, Alejandro. Universidad Nacional Autónoma de México; MéxicoFil: Martinez, Juan Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentina. Universidad Nacional Autónoma de México; MéxicoFil: Ceccarelli, Fadia Sara. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentina. Universidad Nacional Autónoma de México; MéxicoFil: Shaw, Scott R.. University of Wyoming; Estados Unido
Photothermal microscopy applied to the characterization of nuclear fuel pellets
The photothermal photodeflection technique is shown to provide information on the homogeneity of fuel pellets, pore distribution, clustering detection of pure urania and gadolinea and to provide a two-dimensional mapping of the thermal diffusivity correlated to the composition of the interdiffused Gadolinium and Uranium oxide. Histograms of the thermal diffusivity distribution become a reliable quantitative way of quantifying the degree of homogeneity and the width of the histogram can be used as a direct measure of the homogeneity. These quantitative measures of the homogeneity of the samples at microscopic levels provides a protocol that can be used as a reliable specification and quality control method for nuclear fuels, substituting with a single test a battery of expensive, time consuming and operator dependent techniques.Fil: Zaldivar Escola, Facundo. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Física. Laboratorio de Haces Dirigidos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Martinez, Oscar Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Mingolo, Nelida. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Física. Laboratorio de Haces Dirigidos; ArgentinaFil: Kempf, R.. Comisión Nacional de Energía Atómica; Argentin
Increased Mortality from Lung Cancer and Bronchiectasis in Young Adults after Exposure to Arsenic in Utero and in Early Childhood
Arsenic in drinking water is an established cause of lung cancer, and preliminary evidence suggests that ingested arsenic may also cause nonmalignant lung disease. Antofagasta is the second largest city in Chile and had a distinct period of very high arsenic exposure that began in 1958 and lasted until 1971, when an arsenic removal plant was installed. This unique exposure scenario provides a rare opportunity to investigate the long-term mortality impact of early-life arsenic exposure. In this study, we compared mortality rates in Antofagasta in the period 1989–2000 with those of the rest of Chile, focusing on subjects who were born during or just before the peak exposure period and who were 30–49 years of age at the time of death. For the birth cohort born just before the high-exposure period (1950–1957) and exposed in early childhood, the standardized mortality ratio (SMR) for lung cancer was 7.0 [95% confidence interval (CI), 5.4–8.9; p < 0.001] and the SMR for bronchiectasis was 12.4 (95% CI, 3.3–31.7; p < 0.001). For those born during the high-exposure period (1958–1970) with probable exposure in utero and early childhood, the corresponding SMRs were 6.1 (95% CI, 3.5–9.9; p < 0.001) for lung cancer and 46.2 (95% CI, 21.1–87.7; p < 0.001) for bronchiectasis. These findings suggest that exposure to arsenic in drinking water during early childhood or in utero has pronounced pulmonary effects, greatly increasing subsequent mortality in young adults from both malignant and nonmalignant lung disease
Risk assessment algorithm for power transformer fleets based on condition and strategic importance
In every electric power system, power transformers (PT) play a critical role. Under ideal circumstances, PT should receive the utmost care to maintain the highest operative condition during their lifetime. Through the years, different approaches have been developed to assess the condition and the inherent risk during the operation of PT. However, most proposed methodologies tend to analyze PT as individuals and not as a fleet. A fleet assessment helps the asset manager make sound decisions regarding the maintenance scheduling for groups of PT with similar conditions. This paper proposes a new methodology to assess the risk of PT fleets, considering the technical condition and the strategic importance of the units. First, the state of the units was evaluated using a health index (HI) with a fuzzy logic algorithm. Then, the strategic importance of each unit was assessed using a weighting technique to obtain the importance index (II). Finally, the analyzed units with similar HI and II were arranged into a set of clusters using the k-means clustering technique. A fleet of 19 PTs was used to validate the proposed method. The obtained results are also provided to demonstrate the viability and feasibility of the assessment model.Fil: Zaldivar Sanchez, Diego Armando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Instituto de Energía Eléctrica. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Energía Eléctrica; ArgentinaFil: Romero Quete, Andrés Arturo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Instituto de Energía Eléctrica. Universidad Nacional de San Juan. Facultad de Ingeniería. Instituto de Energía Eléctrica; ArgentinaFil: Rivera, Sergio R.. Universidad Nacional de Colombia; Colombi
Recommended from our members
Rationale for Advocacy Training in Undergraduate Medical Education
Advocacy is the outspoken support of a cause or group of people. Within the context of medicine, it includes any individual or organized effort that strives to improve health outcomes, expand the inclusivity of the field or promote awareness of a systemic problem that can be ameliorated through legislative efforts. Examples of advocacy in medicine range from fighting for a patient’s costly prescription drug to be covered by insurance, to ensuring that historically underrepresented groups are given the opportunity to achieve a presence in a certain specialty, to contacting legislators to fund efforts to decrease the overcrowding of emergency rooms in public hospitals. Thus, advocacy is crucial across all specialties in the medical field. We believe increasing the exposure of medical students to advocacy training is imperative and will provide them with the necessary tools to beneficially influence the field during their careers. The American Medical Association (AMA) states that physicians must “advocate for the social, economic, educational and political changes that ameliorate suffering and contribute to human well-being” in its Declaration of Professional Responsibility, and other physician and specialty organizations urge such important professional activity as well.1-7
Undergraduate Medical Education (UGME) refers to the instruction received during medical school by students when pursuing an M.D. or D.O. degree. Graduate Medical Education (GME), on the other hand, refers to any type of education after completing an M.D. or D.O. degree, which usually includes residency or fellowship training. Both the United States and Canada recognize the importance of training physicians in advocacy at the GME level, however, advocacy training at the UGME level is less cohesive.8,9 In addition, even at the GME level, though some specialties such as pediatrics do have a requirement for advocacy training, there are no standardized curricula or standards across specialties.10,11
UGME currently lacks compulsory advocacy training integration into the medical school curriculum, although The American Council for Graduate Medical Education (ACGME) in the USA and the Royal College of Physicians and Surgeons (RCPS) in Canada recognize training in advocacy as an objective of GME.12 This could explain the gap between the AMA’s vision of professional responsibility and medical students’ perception of their duties as future physicians. In a 2014 survey, McCrea and Murdoch-Eaton found that medical students “expressed limited appreciation of the concept of social accountability and acknowledged little explicit teaching around underpinning core concepts such as awareness of local health needs, advocacy and nurturing of altruism.”13 They did, however, recognize “the importance of qualities such as advocacy in their future professional careers.” In order to close this gap, UGME should ensure curricular components that foster the nurturing of advocacy are included from an early stage in the instruction of medicine. This will help prevent negative ramifications such as the decline in interest for social issues during medical training, which Bhate et al. describe.14 Bhate also notes that training in advocacy has been shown to change physician’s attitudes towards its practice. Additionally, Press et al. argues that “exposing all medical students to advocacy within medicine may help shape and define their perceived professional role.”15 As advocacy in healthcare can contribute to the enactment of regulations and standards that ultimately improve the public’s health, students should be exposed to formal training that equips them with the necessary tools to engage in effective advocacy and understand their responsibility for engagement. UGME should, therefore, have a requisite to offer advocacy training that is evidence-based, influenced by clinical expertise and contextualized to account for social, economic and political realities.
Lastly, these advocacy-driven initiatives are likely to lead to an improvement in patient-centered measures such as patient satisfaction. Feuerwerker et al. argue that the creation of a position called "Patient Advocate" by a medical student in pre-clinical years would make patients feel more satisfied with their care in the ED and teach students to actively solve patient's frustrations.16 In a similar project, Ward et al. show through their “Patient Advocate Project” that outpatient satisfaction survey data from pre-, peri-, and post-provider (patient advocate) periods demonstrate the implementation of a Patient Advocate Project improved overall satisfaction scores in the ED during the peri-intervention period.17 Knowing that advocacy training can positively impact the quality of care as judged from a patient’s perspective should stand out as a driving force to implement these changes at a formative time in the careers of medical professionals: during UGME training
Near-field cathodoluminescence studies on n-doped gallium nitride films
Near-field cathodoluminescence (NFCL) has been used to characterize hydride vapor phase epitaxy grown n-GaN films. This technique can obtain high resolution luminescence images and perform local measurements of the diffusion length for minority carriers in different parts of the sample. NFCL contrast observed in round growth hillocks at the sample surface, with a diameter of less than 10 mum, is compared with that observed by conventional cathodoluminescence in scanning electron microscope (CLSEM) techniques. In particular NFCL images reveal features not detected by CLSEM which is explained by the fact that under near field conditions the signal arises from a depth of only several tens of nanometers and is then directly related to the surface hillocks. Diffusion lengths of about 0.4 and 4 mum have been found for the holes in different regions of the samples at room temperature. The order of magnitude of these minority carriers diffusion lengths is in good agreement with previous measurements performed at different GaN samples with other techniques. The NFCL contrast and the differences in the measured diffusion lengths are discussed and explained by variations in local trap concentrations
Surgical Options for the Refractive Correction of Keratoconus: Myth or Reality
Keratoconus provides a decrease of quality of life to the patients who suffer from it. The treatment used as well as the method to correct the refractive error of these patients may influence on the impact of the disease on their quality of life. The purpose of this review is to describe the evidence about the conservative surgical treatment for keratoconus aiming to therapeutic and refractive effect. The visual rehabilitation for keratoconic corneas requires addressing three concerns: halting the ectatic process, improving corneal shape, and minimizing the residual refractive error. Cross-linking can halt the disease progression, intrastromal corneal ring segments can improve the corneal shape and hence the visual quality and reduce the refractive error, PRK can correct mild-moderate refractive error, and intraocular lenses can correct from low to high refractive error associated with keratoconus. Any of these surgical options can be performed alone or combined with the other techniques depending on what the case requires. Although it could be considered that the surgical option for the refracto-therapeutic treatment of the keratoconus is a reality, controlled, randomized studies with larger cohorts and longer follow-up periods are needed to determine which refractive procedure and/or sequence are most suitable for each case
Acetaldehyde and hexanaldehyde from cultured white cells
<p>Abstract</p> <p>Background</p> <p>Noninvasive detection of innate immune function such as the accumulation of neutrophils remains a challenge in many areas of clinical medicine. We hypothesized that granulocytes could generate volatile organic compounds.</p> <p>Methods</p> <p>To begin to test this, we developed a bioreactor and analytical GC-MS system to accurately identify and quantify gases in trace concentrations (parts per billion) emitted solely from cell/media culture. A human promyelocytic leukemia cell line, HL60, frequently used to assess neutrophil function, was grown in serum-free medium.</p> <p>Results</p> <p>HL60 cells released acetaldehyde and hexanaldehyde in a time-dependent manner. The mean ± SD concentration of acetaldehyde in the headspace above the cultured cells following 4-, 24- and 48-h incubation was 157 ± 13 ppbv, 490 ± 99 ppbv, 698 ± 87 ppbv. For hexanaldehyde these values were 1 ± 0.3 ppbv, 8 ± 2 ppbv, and 11 ± 2 ppbv. In addition, our experimental system permitted us to identify confounding trace gas contaminants such as styrene.</p> <p>Conclusion</p> <p>This study demonstrates that human immune cells known to mimic the function of innate immune cells, like neutrophils, produce volatile gases that can be measured <it>in vitro </it>in trace amounts.</p
Nonmalignant Respiratory Effects of Chronic Arsenic Exposure from Drinking Water among Never-Smokers in Bangladesh
BACKGROUND: Arsenic from drinking water has been associated with malignant and nonmalignant respiratory illnesses. The association with nonmalignant respiratory illnesses has not been well established because the assessments of respiratory symptoms may be influenced by recall bias or interviewer bias because participants had visible skin lesions.
OBJECTIVES: We examined the relationship of the serum level of Clara cell protein CC 16-a novel biomarker for respiratory illnesses-with well As, total urinary As, and urinary As methylation indices.
METHODS: We conducted a cross-sectional study in nonsmoking individuals (n = 241) selected from a large cohort with a wide range of As exposure (0.1-761 mu g/L) from drinking water in Bangladesh. Total urinary As, urinary As metabolites, and serum CC16 were measured in urine and serum samples collected at baseline of the parent cohort study.
RESULTS: We observed an inverse association between urinary As and serum CC 16 among persons with skin lesions (beta = -0. 13, p = 0.01). We also observed a positive association between secondary methylation index in urinary As and CC16 levels (beta = 0. 12,,P = 0.05) in the overall study population; the association was stronger among people without skin lesions (beta = 0. 18, p = 0.04), indicating that increased methylation capability may be protective against As-induced respiratory damage. In a subsample of study participants undergoing spirometric measures (n = 3 1), we observed inverse associations between urinary As and predictive FEV1 (forced expiratory volume measured in 1 sec) (r = -0.37; FEV1/forced vital capacity ratio and primary methylation index (r = -0.42, p = 0.01).
CONCLUSIONS: The findings suggest that serum CC 16 may be a useful biomarker of epithelial lung damage in individuals with arsenical skin lesions. Also, we observed the deleterious respiratory effects of As exposure at concentrations lower than reported in earlier studies
Paleomagnetism from Deception Island (South Shetlands archipelago, Antarctica), new insights into the interpretation of the volcanic evolution using a geomagnetic model
Deception Island shows the most recent exposed active volcanism in the northern boundary of the Bransfield Trough. The succession of the volcanic sequence in the island is broadly divided into pre- and post-caldera collapse units although a well-constrained chronological identification of the well-defined successive volcanic episodes is still needed. A new paleomagnetic investigation was carried out on 157 samples grouped in 20 sites from the volcanic deposits of Deception Island (South Shetlands archipelago, Antarctic Peninsula region) distributed in: (1) volcanic breccia (3 sites) and lavas (2 sites) prior to the caldera collapse; (2) lavas emplaced after the caldera collapse (10 sites); and (3) dikes cutting pre- and the lower- most post-caldera collapse units (5 sites). The information revealed by paleomagnetism provides new data about the evolution of the multi-episodic volcanic edifice of this Quaternary volcano, suggesting that the present-day position of the volcanic materials is close to their original emplace- ment position. The new data have been combined with previous paleomagnetic results in order to tentatively propose an age when comparing the paleomagnetic data with a global geomagnetic model. Despite the uncertainties in the use of averaged paleomagnetic data per volcanic units, the new data in combination with tephra occurrences noted elsewhere in the region suggest that the pre-caldera units (F1 and F2) erupted before 12,000 year BC, the caldera collapse took place at about 8300 year BC, and post-cal- dera units S1 and S2 are younger than 2000 year BC
- …