5,139 research outputs found
An overview of anthropogenic electromagnetic radiations as risk to pollinators and pollination
Pollinators play a key functional role in most terrestrial ecosystems and provide important ecosystem service to maintain wild plant communities and agricultural productivity. The decline in pollinators has been related to anthropogenic disturbances such as habitat loss, alterations in land use, and climate change. The surge in mobile telephony has led to a marked increase in electromagnetic fields in the atmosphere, which may affect pollinator and pollination. Several laboratory studies have reported negative effects of electromagnetic radiation on reproduction, development, and navigation in insects. The abundance of insects such as the beetle, wasp, and hoverfly, decreased with electromagnetic radiation(EMR), whereas the abundance of underground-nesting wild bees and bee fly unexpectedly increased with EMR. Potential risks for pollinators and biodiversity are anthropogenic radiofrequency electromagnetic radiation (AREMR) (light, radiofrequency). Artificial light at night (ALAN) can alter the function and abundance of pollinator. Evidence of impacts of AREMR is not adequate due to a lack of high quality, field-realistic studies. Whether pollinators experiencing a threat of ALAN or AREMR, while major knowledge gap exists. In this review, the effects of EMR on wild pollinator groups such as wild bees, hoverflies, bee flies, beetles, butterflies, and wasps etc. have been highlighted. Researchers are also recommended for further study on the effects of EMR on insects. This study will be significant to conserve pollinators and other important insects.
-Ga<sub>2</sub>O<sub>3</sub> in Power Electronics Converters: Opportunities & Challenges
In this work, the possibility of using different generations of -Ga2O3 as an ultra-wide-bandgap power semiconductor device for high power converter applications is explored. The competitiveness of -Ga2O3 for power converters in still not well quantified, for which the major determining factors are the on-state resistance, , reverse blocking voltage, , and the thermal resistance, . We have used the best reported device specifications from literature, both in terms of reports of experimental measurements and potential demonstrated by computer-aided designs, to study power converter performance for different device generations. Modular multilevel converter-based voltage source converters are identified as a topology with significant potential to exploit these device characteristics. The performance of MVDC & HVDC converters based on this topology have been analysed, focusing on system level power losses and case temperature rise at the device level. Comparisons of these -Ga2O3 devices are made against contemporary SiC-FET and Si-IGBTs. The results have indicated that although the early -Ga2O3 devices are not competitive to incumbent Si-IGBT and SiC-FET modules, the latest experimental measurements on NiOX/-Ga2O3 and -Ga2O3/diamond significantly surpass the performance of incumbent modules. Furthermore, parameters derived from semiconductor-level simulations indicate that the -Ga2O3/diamond in superjunction structures delivers even superior performance in these power converters
Coastal Multi-hazard vulnerability mapping: A case study along the coast of Nellore District, East Coast of India
The study area coastal zone of Nellore district is experiencing frequent inundation by natural disasters. The current study is focused on generating Multi-hazard vulnerability map using the parameters historical storm surge heights, future sea level, future shoreline and high resolution coastal topography. The area is experiencing the severe coastal erosion up to 7 m/y along some stretches poses a threat. An area totaling 1708.36 sq. km. is found to fall under the multi-hazard zone and the coastal population are under threat due to future storms, erosion, accelerated sea level rise, etc. The image enhancement, interpretation and GIS overlay techniques along with data used here are effective to produce Multi-hazard vulnerability maps. These Maps are become vital tools for the coastal disaster management during an event and to take suitable decision on the future developments
Prevalence of Eye Diseases of Cattle in Bihar, India
The Bihar state of India is having 12.56 million of cattle population and about 15.73% crossbred animals. But, poor management and harsh weather condition make animals vulnerable to various eye diseases. The present investigation was carried out in different districts of Bihar to find the incidences of eye ailments of cattle irrespective of age, breed, sex, season and types of diseases that causes a great economic loss to the farmers. Out of 2832 surveyed animals 15.22% animals were found to be sufferer of various eye diseases. Among the eye ailments 8.93% were corneal opacity, 2.01% Infectious Bovine Keratoconjunctivitis, 1.91% corneal ulcers, 0.81% cataracts, 0.67% glaucoma, 0.46% staphyloma, 0.25% micro cornea and 0.18% were corneal dermoid. Statistical analyses revealed that there were significant (P<0.01)differences among breeds, sexes, age groups and seasons with respect to the occurrence of eye diseases. The crossbred animals (17.74%) were found to be more susceptible than the zebu
cattle (13.45%). The male animals (20.96%) and younger age groups (19.00%) found to be more sufferers than the female (12.08%) and adult animals (13.33%). Seasonal variation with
the highest incidences in preβmonsoon (4.66%), followed by monsoon (3.57%), postβmonsoon (3.53%) and lowest in winter (3.46%) months were noticed. Unilateral eye infections (13.67%) were more than the bilateral (1.55%). The eye diseases could be prevented through better management practices like housing, feeding and timely health care of animals. This record was migrated from the OpenDepot repository service in June, 2017 before shutting down
Mechanism of Action of Secreted Newt Anterior Gradient Protein
Anterior gradient (AG) proteins have a thioredoxin fold and are targeted to the secretory pathway where they may act in the ER, as well as after secretion into the extracellular space. A newt member of the family (nAG) was previously identified as interacting with the GPI-anchored salamander-specific three-finger protein called Prod1. Expression of nAG has been implicated in the nerve dependence of limb regeneration in salamanders, and nAG acted as a growth factor for cultured newt limb blastemal (progenitor) cells, but the mechanism of action was not understood. Here we show that addition of a peptide antibody to Prod1 specifically inhibit the proliferation of blastema cells, suggesting that Prod1 acts as a cell surface receptor for secreted nAG, leading to S phase entry. Mutation of the single cysteine residue in the canonical active site of nAG to alanine or serine leads to protein degradation, but addition of residues at the C terminus stabilises the secreted protein. The mutation of the cysteine residue led to no detectable activity on S phase entry in cultured newt limb blastemal cells. In addition, our phylogenetic analyses have identified a new Caudata AG protein called AG4. A comparison of the AG proteins in a cell culture assay indicates that nAG secretion is significantly higher than AGR2 or AG4, suggesting that this property may vary in different members of the family
Low energy H+CO scattering revisited - CO rotational excitation with new potential surfaces
Context. A recent modeling study of brightness ratios for CO rotational transitions in gas typical of the diffuse ISM by Liszt found the role of H collisions to be more important than previously assumed. This conclusion was based on recent quantum scattering calculations using the so-called WKS potential energy surface (PES) which reported a large cross section for the important 0 β 1 rotational transition. This result is in contradiction to one obtained using the earlier BBH PES for which the cross section is quite small and which is consistent with an expected homonuclear-like propensity for even βJ transitions.
Aims. We revisit this contradiction with new scattering calculations using two new ab initio PESs that focus on the important long- range behavior and explore the validity of the apparent departure from the expected even βJ propensity in H-CO rotational excitation obtained with the WKS PES.
Methods. Close-coupling (CC) rigid-rotor calculations for CO(v = 0, J = 0) excitation by H are performed on four different PESs. Two of the PESs are obtained in this work using state-of-the-art quantum chemistry techniques at the CCSD(T) and MRCI levels of theory.
Results. Cross sections for the J = 0 β 1, as well as other odd βJ, transitions are significantly suppressed compared to even βJ transitions in thermal energy CC calculations using the CCSD(T) and MRCI surfaces. This is consistent with the expected even βJ propensity and in contrast to CC calculations using the WKS PES which predict a dominating 0 β 1 transition.
Conclusions. Inelastic collision cross section calculations are sensitive to fine details in the anisotropic components of the PES and its long-range behavior. The current results obtained with new surfaces for H-CO scattering suggest that the original astrophysical assumption that excitation of CO by H2 dominates the kinetics of CO in diffuse ISM gas is likely to remain valid
The views of older women towards mammographic screening: a qualitative and quantitative study
Purpose: Mammographic screening has improved breast cancer survival in the screened age group. This improved survival has not been seen in older women (>70 years) where screening uptake is low. This study explores the views, knowledge and attitudes of older women towards screening.
Methods: Women (>70) were interviewed about breast screening. Interview findings informed the development of a questionnaire which was sent to 1000 women (>70) to quantify their views regarding screening.
Results: Twenty-six women were interviewed and a questionnaire designed. The questionnaire response rate was 48.3% (479/992). Over half (52.9%, 241/456) of respondents were unaware they could request mammography by voluntary self-referral and were unaware of how to arrange this. Most (81.5% 383/470) had not attended breast screening since turning 70. Most (75.6%, 343/454) felt screening was beneficial and would attend if invited. Most, (90.1%, 412/457) felt screening should be offered to all women regardless of age or health.
Conclusions: There is a lack of knowledge about screening in older women. The majority felt that invitation to screening should be extended to the older age group regardless of age or health. The current under-utilised system of voluntary self referral is not supported by older women
Identifying sources, pathways and risk drivers in ecosystems of Japanese Encephalitis in an epidemic-prone north Indian district
Japanese Encephalitis (JE) has caused repeated outbreaks in endemic pockets of India. This study was conducted in Kushinagar, a highly endemic district, to understand the human-animal-ecosystem interactions, and the drivers that influence disease transmission. Utilizing the ecosystems approach, a cross-sectional, descriptive study, employing mixed methods design was employed. Four villages (two with pig-rearing and two without) were randomly selected from a high, a medium and a low burden (based on case counts) block of Kushinagar. Children, pigs and vectors were sampled from these villages. A qualitative arm was incorporated to explain the findings from the quantitative surveys. All human serum samples were screened for JE-specific IgM using MAC ELISA and negative samples for JE RNA by rRT-PCR in peripheral blood mononuclear cells. In pigs, IgG ELISA and rRT-PCR for viral RNA were used. Of the 242 children tested, 24 tested positive by either rRT-PCR or MAC ELISA; in pigs, 38 out of the 51 pigs were positive. Of the known vectors, Culex vishnui was most commonly isolated across all biotopes. Analysis of 15 blood meals revealed human blood in 10 samples. Univariable analysis showed that gender, religion, lack of indoor residual spraying of insecticides in the past year, indoor vector density (all species), and not being vaccinated against JE in children were significantly associated with JE positivity. In multivariate analysis, only male gender remained as a significant risk factor. Based on previous estimates of symptomatic: asymptomatic cases of JE, we estimate that there should have been 618 cases from Kushinagar, although only 139 were reported. Vaccination of children and vector control measures emerged as major control activities; they had very poor coverage in the studied villages. In addition, lack of awareness about the cause of JE, lack of faith in the conventional medical healthcare system and multiple referral levels causing delay in diagnosis and treatment emerged as factors likely to result in adverse clinical outcomes
Of cattle, sand flies and men : a systematic review of risk factor analyses for South Asian visceral leishmaniasis and implications for elimination
Background: Studies performed over the past decade have identified fairly consistent epidemiological patterns of risk
factors for visceral leishmaniasis (VL) in the Indian subcontinent.
Methods and Principal Findings: To inform the current regional VL elimination effort and identify key gaps in knowledge,
we performed a systematic review of the literature, with a special emphasis on data regarding the role of cattle because
primary risk factor studies have yielded apparently contradictory results. Because humans form the sole infection reservoir,
clustering of kala-azar cases is a prominent epidemiological feature, both at the household level and on a larger scale.
Subclinical infection also tends to show clustering around kala-azar cases. Within villages, areas become saturated over a
period of several years; kala-azar incidence then decreases while neighboring areas see increases. More recently, post kalaazar
dermal leishmaniasis (PKDL) cases have followed kala-azar peaks. Mud walls, palpable dampness in houses, and peridomestic
vegetation may increase infection risk through enhanced density and prolonged survival of the sand fly vector.
Bed net use, sleeping on a cot and indoor residual spraying are generally associated with decreased risk. Poor micronutrient
status increases the risk of progression to kala-azar. The presence of cattle is associated with increased risk in some studies
and decreased risk in others, reflecting the complexity of the effect of bovines on sand fly abundance, aggregation, feeding
behavior and leishmanial infection rates. Poverty is an overarching theme, interacting with individual risk factors on multiple
levels.
Conclusions: Carefully designed demonstration projects, taking into account the complex web of interconnected risk
factors, are needed to provide direct proof of principle for elimination and to identify the most effective maintenance
activities to prevent a rapid resurgence when interventions are scaled back. More effective, short-course treatment
regimens for PKDL are urgently needed to enable the elimination initiative to succeed
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