279 research outputs found
Despite party pressures, House members’ support for their leadership in procedural votes is not guaranteed
Control of the floor agenda in the U.S. House of Representatives is integral if the majority party wishes to achieve its political and electoral aims. In new research, Jamie L. Carson, Michael H. Crespin, and Anthony J. Madonna find that parties will call on their members’ support during important procedural votes – which influence what is discussed, and the scope and length of the debate – when it is unlikely that voters will punish members for their support. However, despite these party pressures, members’ support is not guaranteed – more moderate and conservative members are less likely to support the leadership when requested
A novel approach to modeling the effects of radiation in Gallium-Arsenide solar cells using Silvaco's atlas software
The effects of radiation in GaAs solar cells has been extensively researched and the results of numerous investigation have yielded a considerable amount of information about the degradation in irradiated solar cells. This thesis establishes a novel method in which to use Silvaco's physically-based device simulator, ATLAS, to model the effects of radiation on solar cell output characteristics. A virtual model representing a single junction GaAs solar cell was created in ATLAS. The effects of radiation were modeled using carrier trapping statements representing the defects associated with various fluence levels of 1 MeV electron radiation which were characterized with Deep Level Transient Spectroscopy techniques. The resulting output characteristics of the virtual solar cell, illuminated with a simulated AM0 spectrum, were compared to published experimental measurements for GaAs solar cells of the same dimensions. The virtual solar cell demonstrated a good correlation between the measured and virtual solar cell output characteristics and accurate representation of the spectral response. Complete ATLAS and MATLAB codes are included in appendices.http://archive.org/details/anovelpproachtom109451447Major, United States Marine CorpsApproved for public release; distribution is unlimited
In order to increase competition in U.S. House races, states should look to extra-legislative bodies to redraw congressional boundaries
Politicians and pundits alike regularly bemoan the lack of electoral competition in congressional races as incumbent reelection rates frequently soar to over 90 percent. Redistricting and gerrymandering are often blamed as a way to lock members into their seats for at least a decade. Jamie L. Carson, Michael H. Crespin and Ryan D. Williamson ask if there are ways to inject more competition into elections during the mandated redistricting cycles. Based on an analysis of redistricting cycles from 1972 to 2012, they show that commission and court-drawn districts experience marginally more competition than those drawn by state legislatures. These results provide additional support for the argument that one way to increase the competitiveness of congressional elections is to allow extra-legislative bodies to draw congressional district boundaries
Rapid longitudinal migrations of the filament front off Namibia (SE Atlantic) during the past 70 kyr
Although productivity variations in coastal upwelling areas are mostly attributed to changes in wind strength, productivity dynamics in the Benguela Upwelling System (BUS) is less straightforward due to its complex atmospheric and hydrographic settings. In view of these settings, past productivity variations in the BUS can be better investigated with downcore sediments representing different productivity regimes. In this study, two sediment cores retrieved at ca. 25°–26°S in the BUS and representing different productivity regimes were studied. By using micropaleontological, geochemical and temperature proxies measured on core MD96-2098, recovered at 2910 m water depth in the bathypelagic zone at 26°S off Namibia, variations of filament front location, productivity and temperature in the central BUS over the past 70 kyr were reconstructed. The comparison with newly-generated alkenone-based sea-surface temperature (SST) and previously obtained data at site GeoB3606-1 (~ 25°S; ca. 50 km shoreward from MD96-2098) allowed the recognition of four main phases: (1) upwelling front above the mid slope (70 kyr–44 kyr), (2) seaward displacement of the upwelling front beyond the mid slope (44 kyr–31 kyr), (3) main upwelling front over the hemipelagial (31 kyr–19 kyr), and (4) shoreward contraction of the upwelling filament, and decreased upwelling strength over most of the uppermost bathypelagic (19 kyr–6 kyr). The latitudinal migration of the Southern Hemisphere westerlies and the consequent contractions and expansions of the subpolar gyre played a significant role in millennial and submillennial variability of SST off Namibia. The strength of the southeasterly trade winds, rapid sea-level variations and the equatorward leakage of Antarctic silicate might have acted as amplifiers. Although late Quaternary variations of productivity and upwelling intensity in eastern boundary current systems are thought to be primarily linked to the variability in wind stress, this multi-parameter reconstruction shows that interplaying mechanisms defined the temporal variation pattern of the filament front migrations and the diatom production off Namibia during the past 70 kyr
Injection of insect membrane in Xenopus oocyte: An original method for the pharmacological characterization of neonicotinoid insecticides
Insect nicotinic acetylcholine receptors (nAChRs) represent a major target of insecticides, belonging to the neonicotinoid family. However, the pharmacological profile of native nAChRs is poorly documented, mainly because of a lack of knowledge of their subunit stoichiometry, their tissue distribution and the weak access to nAChR-expressing cells. In addition, the expression of insect nAChRs in heterologous systems remains hard to achieve. Therefore, the structure–activity characterization of nAChR-targeting insecticides is made difficult. The objective of the present study was to characterize insect nAChRs by an electrophysiological approach in a heterologous system naturally devoid of these receptors to allow a molecular/cellular investigation of the mode of action of neonicotinoids
One-Pot Acid-Catalyzed Ring-Opening/Cyclization/Oxidation of Aziridines with N-Tosylhydrazones: Access to 1,2,4-Triazines
A new, three-step, telescoped reaction sequence for the regioselective conversion of N-tosyl hydrazones and aziridines to 3,6-disubstituted and 3,5,6-trisubstituted 1,2,4-triazines is described. The process involves an efficient nucleophilic ring opening of the aziridine, giving access to a wide range of aminohydrazones, isolated with excellent yields. A “one-pot” procedure, combining the ring opening with a cyclization and an oxidation step, allows the preparation of diversified triazines in good yields.This work was supported by a postdoctoral fellowship from Pfizer (L.C.) and EPSRC Grant Nos. EP/K009494/1 and EP/M004120/1 (S.V.L.). We also thank Dr. Andrew D. Bond for conducting X-ray crystallographic analysis
Sublethal dose effects of a neonicotinoid insecticide, clothianidin, on sex pheromone responses in the black cutworm moth
The COVID-related mental health load of neonatal healthcare professionals: a multicenter study in Italy
Background: The COVID-19 pandemic has dramatically affected healthcare professionals’ lives. We investigated the potential mental health risk faced by healthcare professionals working in neonatal units in a multicentre cross-sectional observational study. Methods: We included all healthcare personnel of seven level-3 and six level-2 neonatal units in Tuscany, Italy. We measured the level of physical exposure to COVID-19 risk, self-reported pandemic-related stress, and mental health load outcomes (anxiety, depression, burnout, psychosomatic symptoms, and post-traumatic symptoms) using validated, self-administered, online questionnaires during the second pandemic wave in Italy (October 2020 to March 2021). Results: We analyzed 314 complete answers. Scores above the clinical cutoff were reported by 91% of participants for symptoms of anxiety, 29% for post-traumatic symptoms, 13% for burnout, and 3% for symptoms of depression. Moreover, 50% of the participants reported at least one psychosomatic symptom. Pandemic-related stress was significantly associated with all the measured mental health load outcomes, with an Odds Ratio of 3.31 (95% confidence interval: 1.87, 5.88) for clinically relevant anxiety, 2.46 (1.73, 3.49) for post-traumatic symptoms, 1.80 (1.17, 2.79) for emotional exhaustion, and 2.75 (1.05, 7.19) for depression. Female health care professionals displayed a greater risk of anxiety, and male health care professionals and nurses, of depressive symptoms. Conclusions: Despite the low direct clinical impact of COVID-19 in newborns, neonatal professionals, due to both living in a situation of uncertainty and personal exposure to contacts with parents and other relatives of the newborns, and having to carry out activities once routine and now fraught with uncertainty, displayed clear signs of mental health load outcomes. They must be considered a specific population at risk for psychological consequences during the pandemic
No association between fear of hypoglycemia and blood glucose variability in type 1 diabetes: The cross-sectional VARDIA study
AIMS: In type 1 diabetes (T1D), treatment efficacy is limited by the unpredictability of blood glucose results and glycemic variability (GV). Fear of Hypoglycemia (FOH) remains a major brake for insulin treatment optimization. We aimed to assess the association of GV with FOH in participants with T1D in an observational cross-sectional study performed in 9 French Diabetes Centres (NCT02790060).
METHODS: Participants were T1D for ≥5 years, aged 18-75 years, on stable insulin therapy for ≥3 months. The coefficient of variation (CV) of blood glucose and mean amplitude of glycemic excursions (MAGE) were used to assess GV from 7-point self-monitoring of blood glucose (SMBG). FOH was assessed using the validated French version of the Hypoglycemia Fear Survey-II (HFS-II) questionnaire.
RESULTS: Among a total of 570 recruited participants, 298 were suitable for analysis: 46% women, 58% on continuous subcutaneous insulin infusion [CSII], mean age 49 ± 16 years, HbA1c 7.5 ± 0.9%, HFS-II score 67 ± 18 and 12% with recent history of severe hypoglycemia during the previous 6 months, mean CV 39.8 ± 9.7% and MAGE 119 ± 42 mg/dL. CV and MAGE did not significantly correlate with HFS-II score (R = -0.05;P = 0.457 and R = 0.08;P = 0.170). Participants with severe hypoglycemia in the previous 6 months had higher HFS scores. Participants with higher HFS scores presented more hypoglycemias during follow-up.
CONCLUSIONS: FOH as determined using the HFS-II questionnaire was not associated with 7-point SMBG variability in participants with T1D, but was associated with a positive history of severe hypoglycemia. Higher FOH was associated with higher frequency of hypoglycemia during follow-up
Unexpected effects of low doses of a neonicotinoid insecticide on behavioral responses to sex pheromone in a pest insect
In moths, which include many agricultural pest species, males are attracted by female-emitted sex pheromones. Although integrated pest management strategies are increasingly developed, most insect pest treatments rely on widespread use of neurotoxic chemicals, including neonicotinoid insecticides. Residual accumulation of low concentrations of these insecticides in the environment is known to be harmful to beneficial insects such as honey bees. This environmental stress probably acts as an "info-disruptor" by modifying the chemical communication system, and therefore decreases chances of reproduction in target insects that largely rely on olfactory communication. However, low doses of pollutants could on the contrary induce adaptive processes in the olfactory pathway, thus enhancing reproduction. Here we tested the effects of acute oral treatments with different low doses of the neonicotinoid clothianidin on the behavioral responses to sex pheromone in the moth Agrotis ipsilon using wind tunnel experiments. We show that low doses of clothianidin induce a biphasic effect on pheromone-guided behavior. Surprisingly, we found a hormetic-like effect, improving orientation behavior at the LD20 dose corresponding to 10 ng clothianidin. On the contrary, a negative effect, disturbing orientation behavior, was elicited by a treatment with a dose below the LD0 dose corresponding to 0.25 ng clothianidin. No clothianidin effect was observed on behavioral responses to plant odor. Our results indicate that risk assessment has to include unexpected effects of residues on the life history traits of pest insects, which could then lead to their adaptation to environmental stress
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