801 research outputs found
Inhibition of Alkali Metal Reduction of 1-Adamantanol by London Dispersion Effects
A series of alkali metal 1-adamantoxide (OAd1) complexes of formula [M(OAd1)(HOAd1)2], where M=Li, Na or K, were synthesised by reduction of 1-adamantanol with excess of the alkali metal. The syntheses indicated that only one out of every three HOAd1 molecules was reduced. An X-ray diffraction study of the sodium derivative shows that the complex features two unreduced HOAd1 donors as well as the reduced alkoxide (OAd1), with the Ad1 fragments clustered together on the same side of the NaO3 plane, contrary to steric considerations. This is the first example of an alkali metal reduction of an alcohol that is inhibited from completion due to the formation of the [M(OAd1)(HOAd1)2] complexes, stabilized by London dispersion effects. NMR spectroscopic studies revealed similar structures for the lithium and potassium derivatives. Computational analyses indicate that decisive London dispersion effects in the molecular structure are a consequence of the many C−H⋅⋅⋅H−C interactions between the OAd1 groups.Peer reviewe
Lymphoepithelial Cyst of the Pancreas.
The final, published version of this article is available at doi: 10.1159/000445373Lymphoepithelial cyst (LEC) of the pancreas is an extremely rare, benign pancreatic cystic lesion that is difficult to differentiate preoperatively from other cystic pancreatic lesions. LEC may have malignant potential. Here, we describe a case of LEC of the pancreas - initially suspected to be a mucinous cyst neoplasm - in an elderly man presenting with abdominal pain, who went on to have a distal pancreatectomy and splenectomy. We also review the relevant literature and discuss implications for the diagnosis and management of this rare lesion
Exact Cover with light
We suggest a new optical solution for solving the YES/NO version of the Exact
Cover problem by using the massive parallelism of light. The idea is to build
an optical device which can generate all possible solutions of the problem and
then to pick the correct one. In our case the device has a graph-like
representation and the light is traversing it by following the routes given by
the connections between nodes. The nodes are connected by arcs in a special way
which lets us to generate all possible covers (exact or not) of the given set.
For selecting the correct solution we assign to each item, from the set to be
covered, a special integer number. These numbers will actually represent delays
induced to light when it passes through arcs. The solution is represented as a
subray arriving at a certain moment in the destination node. This will tell us
if an exact cover does exist or not.Comment: 20 pages, 4 figures, New Generation Computing, accepted, 200
Mechanochemical action of the dynamin protein
Dynamin is a ubiquitous GTPase that tubulates lipid bilayers and is
implicated in many membrane severing processes in eukaryotic cells. Setting the
grounds for a better understanding of this biological function, we develop a
generalized hydrodynamics description of the conformational change of large
dynamin-membrane tubes taking into account GTP consumption as a free energy
source. On observable time scales, dissipation is dominated by an effective
dynamin/membrane friction and the deformation field of the tube has a simple
diffusive behavior, which could be tested experimentally. A more involved,
semi-microscopic model yields complete predictions for the dynamics of the tube
and possibly accounts for contradictory experimental results concerning its
change of conformation as well as for plectonemic supercoiling.Comment: 17 pages, 4 figures; typos corrected, reference adde
Framework Report: The AIDS Accountability Workplace Scorecard, September 2011
The aim of the AIDS Accountability Workplace Scorecard is to improve HIV and AIDS workplace programmes in
the countries and sectors most affected by the disease, and improve the health of employees, their families
and communities. Through this initiative we will: / 1. Provide tools for HIV and AIDS workplace programme monitoring and evaluation
AAI has developed scorecard tools for small, medium and large workplaces, which can be used to assess a
global, regional or national HIV and AIDS programme or interventions at a specific workplace site. The
scorecards can serve as both internal monitoring and evaluation tools and as assessments to present to
stakeholders within and outside the organization. / 2. Publish annual Rankings of HIV and AIDS Workplace Programmes
Scorecard users who wish to receive a ranking analysis and recommendations for how to improve their
programmes can submit their scorecards to AAI. AAI ‘s ranking analysis will allow users to compare their
performance with others and over time also measure their own progress. Respondents will be encouraged to
publish their ranking in AAI’s yearly Ranking Reports. / 3. Share good practice
The knowledge and good practices generated through the published rankings will be used to stimulate
improved HIV and AIDS Workplace Programmes worldwide. Large networks of companies, trade union
confederations, and national and international organizations can use the scorecard as a common framework
for monitoring and evaluation of workplace programmes
Suited for Success? : Suits, Status, and Hybrid Masculinity
This document is the Accepted Manuscript version. The final, definitive version of this paper has been published in Men and Masculinities, March 2017, doi: https://doi.org/10.1177/1097184X17696193, published by SAGE Publishing, All rights reserved.This article analyzes the sartorial biographies of four Canadian men to explore how the suit is understood and embodied in everyday life. Each of these men varied in their subject positions—body shape, ethnicity, age, and gender identity—which allowed us to look at the influence of men’s intersectional identities on their relationship with their suits. The men in our research all understood the suit according to its most common representation in popular culture: a symbol of hegemonic masculinity. While they wore the suit to embody hegemonic masculine configurations of practice—power, status, and rationality—most of these men were simultaneously marginalized by the gender hierarchy. We explain this disjuncture by using the concept of hybrid masculinity and illustrate that changes in the style of hegemonic masculinity leave its substance intact. Our findings expand thinking about hybrid masculinity by revealing the ways subordinated masculinities appropriate and reinforce hegemonic masculinity.Peer reviewe
Women and Illegal Activities: Gender Differences and Women's Willingness to Comply Over Time
In recent years the topics of illegal activities such as corruption or tax evasion have attracted a great deal of attention. However, there is still a lack of substantial empirical evidence about the determinants of compliance. The aim of this paper is to investigate empirically whether women are more willing to be compliant than men and whether we observe (among women and in general) differences in attitudes among similar age groups in different time periods (cohort effect) or changing attitudes of the same cohorts over time (age effect) using data from eight Western European countries from the World Values Survey and the European Values Survey that span the period from 1981 to 1999. The results reveal higher willingness to comply among women and an age rather than a cohort effect. Working Paper 06-5
Generating Random Logic Programs Using Constraint Programming
Testing algorithms across a wide range of problem instances is crucial to
ensure the validity of any claim about one algorithm's superiority over
another. However, when it comes to inference algorithms for probabilistic logic
programs, experimental evaluations are limited to only a few programs. Existing
methods to generate random logic programs are limited to propositional programs
and often impose stringent syntactic restrictions. We present a novel approach
to generating random logic programs and random probabilistic logic programs
using constraint programming, introducing a new constraint to control the
independence structure of the underlying probability distribution. We also
provide a combinatorial argument for the correctness of the model, show how the
model scales with parameter values, and use the model to compare probabilistic
inference algorithms across a range of synthetic problems. Our model allows
inference algorithm developers to evaluate and compare the algorithms across a
wide range of instances, providing a detailed picture of their (comparative)
strengths and weaknesses.Comment: This is an extended version of the paper published in CP 202
Drying affects the fiber network in low molecular weight hydrogels
Low molecular weight gels are formed by the self-assembly of a
suitable small molecule gelator into a three-dimensional network of fibrous
structures. The gel properties are determined by the fiber structures, the number
and type of cross-links and the distribution of the fibers and cross-links in space.
Probing these structures and cross-links is difficult. Many reports rely on
microscopy of dried gels (xerogels), where the solvent is removed prior to
imaging. The assumption is made that this has little effect on the structures, but
it is not clear that this assumption is always (or ever) valid. Here, we use small
angle neutron scattering (SANS) to probe low molecular weight hydrogels
formed by the self-assembly of dipeptides. We compare scattering data for wet
and dried gels, as well as following the drying process. We show that the
assumption that drying does not affect the network is not always correct
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