2,303 research outputs found
Self-Excitation and Feedback Cooling of an Isolated Proton
The first one-proton self-excited oscillator (SEO) and one-proton feedback
cooling are demonstrated. In a Penning trap with a large magnetic gradient, the
SEO frequency is resolved to the high precision needed to detect a one-proton
spin flip. This is after undamped magnetron motion is sideband-cooled to a 14
mK theoretical limit, and despite random frequency shifts (larger than those
from a spin flip) that take place every time sideband cooling is applied in the
gradient. The observations open a possible path towards a million-fold improved
comparison of the antiproton and proton magnetic moments
Past electron-positron g-2 experiments yielded sharpest bound on CPT violation for point particles
In our past experiments on a single electron and positron we measured the
cyclotron and spin-cyclotron difference frequencies omega_c and omega_a and the
ratios a = omega_a/ omega_c at omega_c = 141 Ghz for e^- and e^+ and later,
only for e^-, also at 164 Ghz. Here, we do extract from these data, as had not
done before, a new and very different figure of merit for violation of CPT
symmetry, one similar to the widely recognized impressive limit |m_Kaon -
m_Antikaon|/m_Kaon < 10^-18 for the K-mesons composed of two quarks. That
expression may be seen as comparing experimental relativistic masses of
particle states before and after the C, P, T operations had transformed
particle into antiparticle. Such a similar figure of merit for a non-composite
and quite different lepton, found by us from our Delta a = a^- - a^+ data, was
even smaller, h_bar |omega_a^- - omega_a^+|/2m_0 c^2 = |Delta a| h_bar
omega_c/2m_0 c^2) < 3(12) 10^-22.Comment: Improved content, Editorially approved for publication in PRL, LATEX
file, 5 pages, no figures, 16
Development on drought-stressed host plants affects life history, flight morphology and reproductive output relative to landscape structure
With global climate change, rainfall is becoming more variable. Predicting the responses of species to changing rainfall levels is difficult because, for example in herbivorous species, these effects may be mediated indirectly through changes in host plant quality. Furthermore, species responses may result from a simultaneous interaction between rainfall levels and other environmental variables such as anthropogenic land use or habitat quality. In this eco-evolutionary study, we examined how male and female Pararge aegeria (L.) from woodland and agricultural landscape populations were affected by the development on drought-stressed host plants. Compared with individuals from woodland landscapes, when reared on drought-stressed plants agricultural individuals had longer development times, reduced survival rates and lower adult body masses. Across both landscape types, growth on drought-stressed plants resulted in males and females with low forewing aspect ratios and in females with lower wing loading and reduced fecundity. Development on drought-stressed plants also had a landscape-specific effect on reproductive output; agricultural females laid eggs that had a significantly lower hatching success. Overall, our results highlight several potential mechanisms by which low water availability, via changes in host plant quality, may differentially influence P. aegeria populations relative to landscape structure
Clinical surveillance of thrombotic microangiopathies in Scotland, 2003-2005
The prevalence, incidence and outcomes of haemolytic uraemic syndrome (HUS) and thrombotic thrombocytopaenic purpura (TTP) are not well established in adults or children from prospective studies. We sought to identify both outcomes and current management strategies using prospective, national surveillance of HUS and TTP, from 2003 to 2005 inclusive. We also investigated the links between these disorders and factors implicated in the aetiology of HUS and TTP including infections, chemotherapy, and immunosuppression. Most cases of HUS were caused by verocytotoxin-producing Escherichia coli (VTEC), of which serotype O157 predominated, although other serotypes were identified. The list of predisposing factors for TTP was more varied although use of immunosuppressive agents and severe sepsis, were the most frequent precipitants. The study demonstrates that while differentiating between HUS and TTP is sometimes difficult, in most cases the two syndromes have quite different predisposing factors and clinical parameters, enabling clinical and epidemiological profiling for these disorders
Does Stable Housing Predict Extended Sobriety?
This study will examine adults in the Miami Valley area who have been treated for substance abuse. Using an explanatory quasi-experimental post-test design, we will explore participants’ length of housing and sobriety through a one page survey. Data will be imputed and assessed through SPSS. We will use frequency distributions and measures of central tendency to describe the sample. We will also run an independent t-test to determine differences between stable housing and length of sobriety. We anticipate findings will indicate adults who attain stable housing with have extended sobriety. Implications, limitations, and suggestions for future research will be discussed
Lecanemab in early Alzheimer\u27s disease
BACKGROUND: The accumulation of soluble and insoluble aggregated amyloid-beta (Aβ) may initiate or potentiate pathologic processes in Alzheimer\u27s disease. Lecanemab, a humanized IgG1 monoclonal antibody that binds with high affinity to Aβ soluble protofibrils, is being tested in persons with early Alzheimer\u27s disease.
METHODS: We conducted an 18-month, multicenter, double-blind, phase 3 trial involving persons 50 to 90 years of age with early Alzheimer\u27s disease (mild cognitive impairment or mild dementia due to Alzheimer\u27s disease) with evidence of amyloid on positron-emission tomography (PET) or by cerebrospinal fluid testing. Participants were randomly assigned in a 1:1 ratio to receive intravenous lecanemab (10 mg per kilogram of body weight every 2 weeks) or placebo. The primary end point was the change from baseline at 18 months in the score on the Clinical Dementia Rating-Sum of Boxes (CDR-SB; range, 0 to 18, with higher scores indicating greater impairment). Key secondary end points were the change in amyloid burden on PET, the score on the 14-item cognitive subscale of the Alzheimer\u27s Disease Assessment Scale (ADAS-cog14; range, 0 to 90; higher scores indicate greater impairment), the Alzheimer\u27s Disease Composite Score (ADCOMS; range, 0 to 1.97; higher scores indicate greater impairment), and the score on the Alzheimer\u27s Disease Cooperative Study-Activities of Daily Living Scale for Mild Cognitive Impairment (ADCS-MCI-ADL; range, 0 to 53; lower scores indicate greater impairment).
RESULTS: A total of 1795 participants were enrolled, with 898 assigned to receive lecanemab and 897 to receive placebo. The mean CDR-SB score at baseline was approximately 3.2 in both groups. The adjusted least-squares mean change from baseline at 18 months was 1.21 with lecanemab and 1.66 with placebo (difference, -0.45; 95% confidence interval [CI], -0.67 to -0.23; P\u3c0.001). In a substudy involving 698 participants, there were greater reductions in brain amyloid burden with lecanemab than with placebo (difference, -59.1 centiloids; 95% CI, -62.6 to -55.6). Other mean differences between the two groups in the change from baseline favoring lecanemab were as follows: for the ADAS-cog14 score, -1.44 (95% CI, -2.27 to -0.61; P\u3c0.001); for the ADCOMS, -0.050 (95% CI, -0.074 to -0.027; P\u3c0.001); and for the ADCS-MCI-ADL score, 2.0 (95% CI, 1.2 to 2.8; P\u3c0.001). Lecanemab resulted in infusion-related reactions in 26.4% of the participants and amyloid-related imaging abnormalities with edema or effusions in 12.6%.
CONCLUSIONS: Lecanemab reduced markers of amyloid in early Alzheimer\u27s disease and resulted in moderately less decline on measures of cognition and function than placebo at 18 months but was associated with adverse events. Longer trials are warranted to determine the efficacy and safety of lecanemab in early Alzheimer\u27s disease. (Funded by Eisai and Biogen; Clarity AD ClinicalTrials.gov number, NCT03887455.)
The most storage economical Runge-Kutta methods for the solution of large systems of coupled first-order differential equations
AbstractIt is shown how the attainable minimum for the memory requirements of Runge-Kutta methods can be realised for methods of the third order. These economisable third order methods belong to a one parameter sub-family from which two particular members with low error bound are selected
Behind the wheel: What drives the effects of error handling?
Existing research comparing error management (a strategy focusing on increasing the positive and decreasing the negative consequences of errors) to error prevention (a strategy focusing on working faultlessly), has identified error management as beneficial for multiple outcomes. Yet, due to various methodological limitations, it is unclear whether the effects previously found are due to error prevention, error management, or both. We examine this in an experimental study with a 2 (error prevention: yes vs. no)× 2 (error management: yes vs. no) factorial design. Error prevention had negative effects on cognition and adaptive transfer performance. Error management alleviated worry and boosted one’s perceived self-efficacy. Overall, the results show that error prevention and error management have unique outcomes on negative affect, self-efficacy, cognition, and performance
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