89 research outputs found
A pulsed, low-temperature beam of supersonically cooled free radical OH molecules
An improved system for creating a pulsed, low-temperature molecular beam of
OH radicals has been developed. We use a pulsed discharge to create OH from
HO seeded in Xe during a supersonic expansion, where the high-voltage pulse
duration is significantly shorter than the width of the gas pulse. The pulsed
discharge allows for control of the mean speed of the molecular packet as well
as maintains a low temperature supersonic expansion. A hot filament is placed
in the source chamber to initiate the discharge for shorter durations and at
lower voltages, resulting in a translationally and rotationally colder packet
of OH molecules
Ab initio atomistic thermodynamics and statistical mechanics of surface properties and functions
Previous and present "academic" research aiming at atomic scale understanding
is mainly concerned with the study of individual molecular processes possibly
underlying materials science applications. Appealing properties of an
individual process are then frequently discussed in terms of their direct
importance for the envisioned material function, or reciprocally, the function
of materials is somehow believed to be understandable by essentially one
prominent elementary process only. What is often overlooked in this approach is
that in macroscopic systems of technological relevance typically a large number
of distinct atomic scale processes take place. Which of them are decisive for
observable system properties and functions is then not only determined by the
detailed individual properties of each process alone, but in many, if not most
cases also the interplay of all processes, i.e. how they act together, plays a
crucial role. For a "predictive materials science modeling with microscopic
understanding", a description that treats the statistical interplay of a large
number of microscopically well-described elementary processes must therefore be
applied. Modern electronic structure theory methods such as DFT have become a
standard tool for the accurate description of individual molecular processes.
Here, we discuss the present status of emerging methodologies which attempt to
achieve a (hopefully seamless) match of DFT with concepts from statistical
mechanics or thermodynamics, in order to also address the interplay of the
various molecular processes. The new quality of, and the novel insights that
can be gained by, such techniques is illustrated by how they allow the
description of crystal surfaces in contact with realistic gas-phase
environments.Comment: 24 pages including 17 figures, related publications can be found at
http://www.fhi-berlin.mpg.de/th/paper.htm
A Measurement of the Product Branching Ratio f(b->Lambda_b).BR(Lambda_b->Lambda X) in Z0 Decays
The product branching ratio, f(b->Lambda_b).BR(Lambda_b->Lambda X), where
Lambda_b denotes any weakly-decaying b-baryon, has been measured using the OPAL
detector at LEP. Lambda_b are selected by the presence of energetic Lambda
particles in bottom events tagged by the presence of displaced secondary
vertices. A fit to the momenta of the Lambda particles separates signal from B
meson and fragmentation backgrounds. The measured product branching ratio is
f(b->Lambda_b).BR(Lambda_b->Lambda X) = (2.67+-0.38(stat)+0.67-0.60(sys))%
Combined with a previous OPAL measurement, one obtains
f(b->Lambda_b).BR(Lambda_b->Lambda X) = (3.50+-0.32(stat)+-0.35(sys))%.Comment: 16 pages, LaTeX, 3 eps figs included, submitted to the European
Physical Journal
The Boundary-spanning Role of Democratic Learning Communities: Implementing the IDEALS
This multi-case study investigates characteristics and practices in schools that expand the traditional boundaries of school leadership and transform schools into democratic learning communities based on the level of implementation of the IDEALS framework. This investigation serves as a modus to illuminate democratic processes that change schools and address the needs of the students, not the needs of the adults in the system. A sample of five purposefully selected high schools, from the Midwest USA, was utilized. The schools serve Grade 9—12 students, but vary in size, residential area and socioeconomic status of the students. This study illuminates some of the challenges and strategies that facilitate or impede the process of creating more democratic schools that expand the boundaries of inquiry and discourse to include a broader range of community stakeholders and that respect and embrace issues of equity.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline
Convalescent plasma in patients admitted to hospital with COVID-19 (RECOVERY): a randomised controlled, open-label, platform trial
Background:
Many patients with COVID-19 have been treated with plasma containing anti-SARS-CoV-2 antibodies. We aimed to evaluate the safety and efficacy of convalescent plasma therapy in patients admitted to hospital with COVID-19.
Methods:
This randomised, controlled, open-label, platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]) is assessing several possible treatments in patients hospitalised with COVID-19 in the UK. The trial is underway at 177 NHS hospitals from across the UK. Eligible and consenting patients were randomly assigned (1:1) to receive either usual care alone (usual care group) or usual care plus high-titre convalescent plasma (convalescent plasma group). The primary outcome was 28-day mortality, analysed on an intention-to-treat basis. The trial is registered with ISRCTN, 50189673, and ClinicalTrials.gov, NCT04381936.
Findings:
Between May 28, 2020, and Jan 15, 2021, 11558 (71%) of 16287 patients enrolled in RECOVERY were eligible to receive convalescent plasma and were assigned to either the convalescent plasma group or the usual care group. There was no significant difference in 28-day mortality between the two groups: 1399 (24%) of 5795 patients in the convalescent plasma group and 1408 (24%) of 5763 patients in the usual care group died within 28 days (rate ratio 1·00, 95% CI 0·93–1·07; p=0·95). The 28-day mortality rate ratio was similar in all prespecified subgroups of patients, including in those patients without detectable SARS-CoV-2 antibodies at randomisation. Allocation to convalescent plasma had no significant effect on the proportion of patients discharged from hospital within 28 days (3832 [66%] patients in the convalescent plasma group vs 3822 [66%] patients in the usual care group; rate ratio 0·99, 95% CI 0·94–1·03; p=0·57). Among those not on invasive mechanical ventilation at randomisation, there was no significant difference in the proportion of patients meeting the composite endpoint of progression to invasive mechanical ventilation or death (1568 [29%] of 5493 patients in the convalescent plasma group vs 1568 [29%] of 5448 patients in the usual care group; rate ratio 0·99, 95% CI 0·93–1·05; p=0·79).
Interpretation:
In patients hospitalised with COVID-19, high-titre convalescent plasma did not improve survival or other prespecified clinical outcomes.
Funding:
UK Research and Innovation (Medical Research Council) and National Institute of Health Research
The Family Context as a Foundation for Romantic Relationships: A Person-Centered Multi-Informant Longitudinal Study
This 8-wave person-centered multi-informant study tested whether the quality of parent–adolescent relationships predicted the romantic experiences of young adults and their partners (N = 374; 54.8% girls; Mage = 13.08 years, SDage = 0.48 at the first measurement wave). Perceptions of parent–adolescent relationships were assessed using adolescent, mother, and father reports. Results show that both young adults and their partners reported the highest levels of support, intimacy, and passion when young adults had an authoritative relationship quality with their parents. A distant parent–adolescent relationship quality, however, predicted the lowest support, intimacy, and passion in romantic relationships. Interestingly, the association between parent–adolescent relationships with the experience of young adults’ romantic partners was indirect. Parent–adolescent relationships predicted target young adults’ romantic relationship experiences, which predicted partners’ romantic relationship experiences. Parent–child relationship quality therefore has far-reaching, yet subtle, effects on later romantic relationships, affecting both young adults and their partners
The family context as a foundation for romantic relationships: A person-centered multi-informant longitudinal study
This 8-wave person-centered multi-informant study tested whether the quality of parent-adolescent relationships predicted the romantic experiences of young adults and their partners (N = 374; 54.8% girls; Mage = 13.08 years, SDage = 0.48 at the first measurement wave). Perceptions of parent-adolescent relationships were assessed using adolescent, mother, and father reports. Results show that both young adults and their partners reported the highest levels of support, intimacy, and passion when young adults had an authoritative relationship quality with their parents. A distant parent-adolescent relationship quality, however, predicted the lowest support, intimacy, and passion in romantic relationships. Interestingly, the association between parent-adolescent relationships with the experience of young adults' romantic partners was indirect. Parent-adolescent relationships predicted target young adults' romantic relationship experiences, which predicted partners' romantic relationship experiences. Parent-child relationship quality therefore has far-reaching, yet subtle, effects on later romantic relationships, affecting both young adults and their partners
The family context as a foundation for romantic relationships: A person-centered multi-informant longitudinal study
This 8-wave person-centered multi-informant study tested whether the quality of parent-adolescent relationships predicted the romantic experiences of young adults and their partners (N = 374; 54.8% girls; Mage = 13.08 years, SDage = 0.48 at the first measurement wave). Perceptions of parent-adolescent relationships were assessed using adolescent, mother, and father reports. Results show that both young adults and their partners reported the highest levels of support, intimacy, and passion when young adults had an authoritative relationship quality with their parents. A distant parent-adolescent relationship quality, however, predicted the lowest support, intimacy, and passion in romantic relationships. Interestingly, the association between parent-adolescent relationships with the experience of young adults' romantic partners was indirect. Parent-adolescent relationships predicted target young adults' romantic relationship experiences, which predicted partners' romantic relationship experiences. Parent-child relationship quality therefore has far-reaching, yet subtle, effects on later romantic relationships, affecting both young adults and their partners
Identifying Candidate Biomarkers for Pleomorphic Adenoma: A Case–Control Study
Pleomorphic adenoma (PA) is the most common benign salivary gland tumor. Kallikrein-related peptidases have been identified as biomarkers in many human tumors and may influence tumor behavior. We investigated KLK1−15 messenger ribonucleic acid and proteins in PA specimens to determine a KLK expression profile for this tumor. Fresh frozen PA tissue specimens (n = 26) and matched controls were subjected to quantitative real-time reverse transcription polymerase chain reaction to detect KLK1−15 mRNA. Expression of KLK1, KLK12, KLK13, and KLK8 proteins were then evaluated via immunostaining techniques. Statistical analyses were performed with the level of significance set at P \u3c.05. We observed downregulation of KLK1, KLK12, and KLK13 mRNA expression, and immunostaining studies revealed downregulation of the corresponding proteins. Histologic evidence of capsular perforation was associated with increased KLK1 protein expression. Tumor size was not associated with capsular invasion and/or perforation. This study is the first to detail a KLK expression profile for PA at both the transcriptional level and the protein level. Future work is required to develop clinical applications of these findings
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