3,454 research outputs found
Weak Projections onto a Braided Hopf Algebra
We show that, under some mild conditions, a bialgebra in an abelian and
coabelian braided monoidal category has a weak projection onto a formally
smooth (as a coalgebra) sub-bialgebra with antipode; see Theorem 1.12. In the
second part of the paper we prove that bialgebras with weak projections are
cross product bialgebras; see Theorem 2.12. In the particular case when the
bialgebra is cocommutative and a certain cocycle associated to the weak
projection is trivial we prove that is a double cross product, or biproduct
in Madjid's terminology. The last result is based on a universal property of
double cross products which, by Theorem 2.15, works in braided monoidal
categories. We also investigate the situation when the right action of the
associated matched pair is trivial
What Works to Prevent Sexual Violence Against Children
The data is clear: Sexual violence affects girls and boys in every country around the world. For far too long it has been a silent pandemic, with little awareness of the scope, scale, and consequences of the problem or understanding of potential solutions. That silence has allowed violence against children to perpetuate.
However, there is hope. Recently, there has been a global awakening to the issue of sexual violence against children. While there has been little conversation around solutions to prevent sexual violence, this document intends to change that. By analyzing the best available research on existing strategies and identifying the most effective and promising solutions, we have created a resource for decision-makers, advocates, and program implementers, showcasing what works to prevent sexual violence in childhood and adolescence.
Building off the INSPIRE framework “Seven Strategies to Prevent Violence Against Children,” this evidence review looked at strategies specifically focused on preventing sexual violence. We then categorized these interventions as effective, promising, prudent, conflicting, no effect, or harmful. From school-based, safe-dating programs to community mobilization efforts, these evidence-based solutions showcase that there are practical, cost-effective programs that can help break the cycle of violence.
The evidence shows that sexual violence can — and must — be prevented. Now it’s on us to bring these solutions to scale. Together, we can create a safer world for every child
Unfolding dynamics of proteins under applied force
Understanding the mechanisms of protein folding is a major challenge that is being addressed effectively by collaboration between researchers in the physical and life sciences. Recently, it has become possible to mechanically unfold proteins by pulling on their two termini using local force probes such as the atomic force microscope. Here, we present data from experiments in which synthetic protein polymers designed to mimic naturally occurring polyproteins have been mechanically unfolded. For many years protein folding dynamics have been studied using chemical denaturation, and we therefore firstly discuss our mechanical unfolding data in the context of such experiments and show that the two unfolding mechanisms are not the same, at least for the proteins studied here. We also report unexpected observations that indicate a history effect in the observed unfolding forces of polymeric proteins and explain this in terms of the changing number of domains remaining to unfold and the increasing compliance of the lengthening unstructured polypeptide chain produced each time a domain unfolds
Prognostic factors for disease progression in advanced Hodgkin's disease: an analysis of patients aged under 60 years showing no progression in the first 6 months after starting primary chemotherapy.
The aim of this study was to determine whether a very high-risk group based on presenting characteristics could be identified in patients with advanced Hodgkin's disease who may benefit from high-dose chemotherapy (HDCT). Between 1975 and 1992, 453 previously untreated patients aged under 60 years who did not progress in the first 6 months after the start of standard chemotherapy had their hospital notes reviewed. The outcomes analysed were early disease progression (in the 6- to 18-month window following the start of chemotherapy) and disease progression in the whole of the follow-up period. A Cox regression analysis was used to investigate the combined effects of a number of presenting characteristics on these outcomes. Despite the presence of factors with significant effects on the relative rate of progression, the absolute effects in a group identified as having the poorest prognosis were not especially poor. No group could be defined with a freedom from progression rate of less than 70% over 6-18 months, and the worst prognostic group, which included only 53 patients, had an overall freedom from progression rate of 57% at 5 years. Four other reported prognostic indices were evaluated using our data set, but none of the indices was more successful in identifying a very high-risk group. It has not been possible to define a sufficiently high-risk group of patients with Hodgkin's disease based on presenting characteristics for whom HDCT could be advised as part of primary treatment. The search for more discriminating prognostic factors identifying vulnerable patients with a high risk of relapse must continue before a role can be found for HDCT following conventional chemotherapy in patients without disease progression
Viscosity Dependence of the Folding Rates of Proteins
The viscosity dependence of the folding rates for four sequences (the native
state of three sequences is a beta-sheet, while the fourth forms an
alpha-helix) is calculated for off-lattice models of proteins. Assuming that
the dynamics is given by the Langevin equation we show that the folding rates
increase linearly at low viscosities \eta, decrease as 1/\eta at large \eta and
have a maximum at intermediate values. The Kramers theory of barrier crossing
provides a quantitative fit of the numerical results. By mapping the simulation
results to real proteins we estimate that for optimized sequences the time
scale for forming a four turn \alpha-helix topology is about 500 nanoseconds,
whereas the time scale for forming a beta-sheet topology is about 10
microseconds.Comment: 14 pages, Latex, 3 figures. One figure is also available at
http://www.glue.umd.edu/~klimov/seq_I_H.html, to be published in Physical
Review Letter
Application of next-generation sequencing technologies in virology
The progress of science is punctuated by the advent of revolutionary technologies that provide new ways and scales to formulate scientific questions and advance knowledge. Following on from electron microscopy, cell culture and PCR, next-generation sequencing is one of these methodologies that is now changing the way that we understand viruses, particularly in the areas of genome sequencing, evolution, ecology, discovery and transcriptomics. Possibilities for these methodologies are only limited by our scientific imagination and, to some extent, by their cost, which has restricted their use to relatively small numbers of samples. Challenges remain, including the storage and analysis of the large amounts of data generated. As the chemistries employed mature, costs will decrease. In addition, improved methods for analysis will become available, opening yet further applications in virology including routine diagnostic work on individuals, and new understanding of the interaction between viral and host transcriptomes. An exciting era of viral exploration has begun, and will set us new challenges to understand the role of newly discovered viral diversity in both disease and health
Low-momentum nucleon-nucleon interaction and shell-model calculations
We discuss the use of the low-momentum nucleon-nucleon NN interaction V-low-k
in the derivation of the shell-model effective interaction and emphasize its
practical value as an alternative to the Brueckner G-matrix method. We present
some selected results of our current study of exotic nuclei around closed
shells, which have been obtained starting from the CD-Bonn potential. We also
show some results of calculations performed with different phase-shift
equivalent NN potentials, and discuss the effect of changes in the cutoff
momentum which defines the V-low-k potential.Comment: 5 pages, 5 figures, 1 table, Talk presented at CDN05, 31 Jan - 4 Feb
2005, University of Tokyo, Japa
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