2,995 research outputs found
Shifting Understandings of Lesbianism in Imperial and Weimar Germany
This paper seeks to understand how, and why, understandings of lesbianism shifted in Germany over the course of the late nineteenth and early twentieth centuries. Through close readings of both popular cultural productions and medical and psychological texts produced within the context of Imperial and Weimar Germany, this paper explores the changing nature of understandings of homosexuality in women, arguing that over the course of the late nineteenth and early twentieth centuries, the dominant conceptualization of lesbianism transformed from an understanding of lesbians that was rooted in biology and viewed lesbians as physically masculine “gender inverts”, to one that was grounded in psychology, and understood lesbians as inherently traumatized, mother-fixated, and suicidal. This paper suggests that this shift was facilitated by the increasing influence of psychologists like Sigmund Freud, and greater German preoccupation with trauma and suicide following WWI, and highlights the importance of historical context in shaping self-understanding
Application of diffusion barriers to the refractory fibers of tungsten, columbium, carbon and aluminum oxide
A radio frequency powered ion-plating system was used to plate protective layers of refractory oxides and carbide onto high strength fiber substrates. Subsequent overplating of these combinations with nickel and titanium was made to determine the effectiveness of such barrier layers in preventing diffusion of the overcoat metal into the fibers with consequent loss of fiber strength. Four substrates, five coatings, and two metal matrix materials were employed for a total of forty material combinations. The substrates were tungsten, niobium, NASA-Hough carbon, and Tyco sapphire. The diffusion-barrier coatings were aluminum oxide, yttrium oxide, titanium carbide, tungsten carbide with 14% cobalt addition, and zirconium carbide. The metal matrix materials were IN 600 nickel and Ti 6/4 titanium. Adhesion of the coatings to all substrates was good except for the NASA-Hough carbon, where flaking off of the oxide coatings in particular was observed
Phage display-derived inhibitor of the essential cell wall biosynthesis enzyme MurF
Background
To develop antibacterial agents having novel modes of action against bacterial cell wall biosynthesis, we targeted the essential MurF enzyme of the antibiotic resistant pathogen Pseudomonas aeruginosa. MurF catalyzes the formation of a peptide bond between D-Alanyl-D-Alanine (D-Ala-D-Ala) and the cell wall precursor uridine 5'-diphosphoryl N-acetylmuramoyl-L-alanyl-D-glutamyl-meso-diaminopimelic acid (UDP-MurNAc-Ala-Glu-meso-A2pm) with the concomitant hydrolysis of ATP to ADP and inorganic phosphate, yielding UDP-N-acetylmuramyl-pentapeptide. As MurF acts on a dipeptide, we exploited a phage display approach to identify peptide ligands having high binding affinities for the enzyme.
Results
Screening of a phage display 12-mer library using purified P. aeruginosa MurF yielded to the identification of the MurFp1 peptide. The MurF substrate UDP-MurNAc-Ala-Glumeso-A2pm was synthesized and used to develop a sensitive spectrophotometric assay to quantify MurF kinetics and inhibition. MurFp1 acted as a weak, time-dependent inhibitor of MurF activity but was a potent inhibitor when MurF was pre-incubated with UDP-MurNAc-Ala-Glu-meso-A2pm or ATP. In contrast, adding the substrate D-Ala-D-Ala during the pre-incubation nullified the inhibition. The IC50 value of MurFp1 was evaluated at 250 μM, and the Ki was established at 420 μM with respect to the mixed type of inhibition against D-Ala-D-Ala.
Conclusion
MurFp1 exerts its inhibitory action by interfering with the utilization of D-Ala-D-Ala by the MurF amide ligase enzyme. We propose that MurFp1 exploits UDP-MurNAc-Ala-Glu-meso-A2pm-induced structural changes for better interaction with the enzyme. We present the first peptide inhibitor of MurF, an enzyme that should be exploited as a target for antimicrobial drug development
Modeling and predicting the shape of the far-infrared to submillimeter emission in ultra-compact HII regions and cold clumps
Dust properties are very likely affected by the environment in which dust
grains evolve. For instance, some analyses of cold clumps (7 K- 17 K) indicate
that the aggregation process is favored in dense environments. However,
studying warm (30 K-40 K) dust emission at long wavelength (300
m) has been limited because it is difficult to combine far
infared-to-millimeter (FIR-to-mm) spectral coverage and high angular resolution
for observations of warm dust grains. Using Herschel data from 70 to 500
m, which are part of the Herschel infrared Galactic (Hi-GAL) survey
combined with 1.1 mm data from the Bolocam Galactic Plane Survey (BGPS), we
compared emission in two types of environments: ultra-compact HII (UCHII)
regions, and cold molecular clumps (denoted as cold clumps). With this
comparison we tested dust emission models in the FIR-to-mm domain that
reproduce emission in the diffuse medium, in these two environments (UCHII
regions and cold clumps). We also investigated their ability to predict the
dust emission in our Galaxy. We determined the emission spectra in twelve UCHII
regions and twelve cold clumps, and derived the dust temperature (T) using the
recent two-level system (TLS) model with three sets of parameters and the
so-called T- (temperature-dust emissvity index) phenomenological models,
with set to 1.5, 2 and 2.5. We tested the applicability of the TLS
model in warm regions for the first time. This analysis indicates distinct
trends in the dust emission between cold and warm environments that are visible
through changes in the dust emissivity index. However, with the use of standard
parameters, the TLS model is able to reproduce the spectral behavior observed
in cold and warm regions, from the change of the dust temperature alone,
whereas a T- model requires to be known.Comment: Accepted for publication in A&A. 19 pages, 8 figures, 7 table
The state of gender diversity in medical physics
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154924/1/mp14035.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154924/2/mp14035_am.pd
Maine IT Workforce Skills Management : A study for the Maine State Department of Labor
Executive Summary:
From August 2010 to February 2011 personnel from Information and Innovation at the University of Southern Maine have conducted a study of IT skills needed, possessed and taught in Maine. The goals of this study were to provide fine-grained information to the Maine state Department of Labor to facilitate their workforce development activities.
This study concerns the skills sought after by employers, possessed by unemployed and employed workers and taught in education and training establishments with a bricks and mortar presence in Maine. It relied on data created by third parties and by study personnel. Anecdotal evidence was gathered from meetings with local industry IT professionals as well. This study does not attempt to estimate demand or supply of a given skill, but it does assess which skills are in greatest and least demand, which skills are in greatest and least supply, and which skills are taught more and less often. The results of data analysis are presented in a new measure, skill rank disparity, which exposes skill and training gaps and gluts.
This study provides certain insights into its results, observing individual cases of skills high in demand and low in supply, for example. Insights are also provided in terms of groups of skills that are often taught, often asked for, and whether these groups of skills are well-represented in the Maine IT workforce.
This study also provides specific and actionable recommendatio
Measure of the path integral in lattice gauge theory
We show how to construct the measure of the path integral in lattice gauge
theory. This measure contains a factor beyond the standard Haar measure. Such
factor becomes relevant for the calculation of a single transition amplitude
(in contrast to the calculation of ratios of amplitudes). Single amplitudes are
required for computation of the partition function and the free energy. For
U(1) lattice gauge theory, we present a numerical simulation of the transition
amplitude comparing the path integral with the evolution in terms of the
Hamiltonian, showing good agreement.Comment: 5 pages, 2 figure
Far-Infrared to Millimeter Astrophysical Dust Emission. II: Comparison of the Two-Level Systems (TLS) model with Astronomical Data
In a previous paper we proposed a new model for the emission by amorphous
astronomical dust grains, based on solid-state physics. The model uses a
description of the Disordered Charge Distribution (DCD) combined with the
presence of Two-Level Systems (TLS) defects in the amorphous solid composing
the grains. The goal of this paper is to confront this new model to
astronomical observations of different Galactic environments in the FIR/submm,
in order to derive a set of canonical model parameters to be used as a Galactic
reference to be compared to in future Galactic and extragalactic studies. We
confront the TLS model with existing astronomical data. We consider the average
emission spectrum at high latitudes in our Galaxy as measured with FIRAS and
WMAP, as well as the emission from Galactic compact sources observed with
Archeops, for which an inverse relationship between the dust temperature and
the emissivity spectral index has been evidenced. We show that, unlike models
previously proposed which often invoke two dust components at different
temperatures, the TLS model successfully reproduces both the shape of the
Galactic SED and its evolution with temperature as observed in the Archeops
data. The best TLS model parameters indicate a charge coherence length of
\simeq 13 nm and other model parameters in broad agreement with expectations
from laboratory studies of dust analogs. We conclude that the millimeter excess
emission, which is often attributed to the presence of very cold dust in the
diffuse ISM, is likely caused solely by TLS emission in disordered amorphous
dust grains. We discuss the implications of the new model, in terms of mass
determinations from millimeter continuum observations and the expected
variations of the emissivity spectral index with wavelength and dust
temperature. The implications for the analysis of the Herschel and Planck
satellite data are discussed.Comment: Accepted for publication in A&A (16 pages, 9 figures, 6 tables
Screening for cardiovascular disease risk factors beginning in childhood
Cardiovascular diseases (CVD) are the leading cause of death worldwide. Individual detection and intervention on CVD risk factors and behaviors throughout childhood and adolescence has been advocated as a strategy to reduce CVD risk in adulthood. The U.S. National Heart, Lung, and Blood Institute (NHLBI) has recently recommended universal screening of several risk factors in children and adolescents, at odds with several recommendations of the U.S. Services Task Force and of the U.K. National Screening committee. In the current review, we discuss the goals of screening for CVD risk factors (elevated blood pressure, abnormal blood lipids, diabetes) and behaviors (smoking) in children and appraise critically various screening recommendations. Our review suggests that there is no compelling evidence to recommend universal screening for elevated blood pressure, abnormal blood lipids, abnormal blood glucose, or smoking in children and adolescents. Targeted screening of these risk factors could be useful but specific screening strategies have to be evaluated. Research is needed to identify target populations, screening frequency, intervention, and follow-up. Meanwhile, efforts should rather focus on the primordial prevention of CVD risk factors and at maintaining a lifelong ideal cardiovascular health through environmental, policy, and educational approaches
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