3,328 research outputs found
A Role for Actin, Cdc1p, and Myo2p in the Inheritance of Late Golgi Elements in \u3cem\u3eSaccharomyces cerevisiae\u3c/em\u3e
In Saccharomyces cerevisiae, Golgi elements are present in the bud very early in the cell cycle. We have analyzed this Golgi inheritance process using fluorescence microscopy and genetics. In rapidly growing cells, late Golgi elements show an actin-dependent concentration at sites of polarized growth. Late Golgi elements are apparently transported into the bud along actin cables and are also retained in the bud by a mechanism that may involve actin. A visual screen for mutants defective in the inheritance of late Golgi elements yielded multiple alleles of CDC1. Mutations in CDC1 severely depolarize the actin cytoskeleton, and these mutations prevent late Golgi elements from being retained in the bud. The efficient localization of late Golgi elements to the bud requires the type V myosin Myo2p, further suggesting that actin plays a role in Golgi inheritance. Surprisingly, early and late Golgi elements are inherited by different pathways, with early Golgi elements localizing to the bud in a Cdc1p- and Myo2p-independent manner. We propose that early Golgi elements arise from ER membranes that are present in the bud. These two pathways of Golgi inheritance in S. cerevisiae resemble Golgi inheritance pathways in vertebrate cells
Prevention of awareness during general anesthesia
Awareness during general anesthesia with subsequent explicit recall is a serious and frequently preventable problem that is gaining attention from clinicians and patients alike. Cost-effective interventions that increase vigilance should be implemented to decrease the likelihood of this complication
The on-top pair-correlation density in the homogeneous electron liquid
The ladder theory, in which the Bethe-Goldstone equation for the effective
potential between two scattering particles plays a central role, is well known
for its satisfactory description of the short-range correlations in the
homogeneous electron liquid. By solving exactly the Bethe-Goldstone equation in
the limit of large transfer momentum between two scattering particles, we
obtain accurate results for the on-top pair-correlation density , in both
three dimensions and two dimensions. Furthermore, we prove, in general, the
ladder theory satisfies the cusp condition for the pair-correlation density
at zero distance .Comment: 8 pages, 4 figure
Implementation of an emergency medicine research associates program: Sharing 20 years of experience
© 2018 Abar et al. Introduction: The use of research associates (RA) programs to facilitate study enrollment in the emergency department was initiated during the mid-1990s. The University of Rochester Medical Center (URMC) was an early adopting site for this model, which has experienced considerable growth and development over the past 20 years. Methods: Our goal was to detail the Emergency Department Research Associates (EDRA) program processes developed at the URMC that has led to our program’s sustainability and productivity. These processes, and the lessons learned during their development, can assist institutions seeking to establish an RA program or refine an existing program. Results: Defined procedures for selecting, training, and monitoring EDRAs have been created and refined with the goal of maximizing study enrollment and minimizing protocol deviations. Our EDRA program functions as a paid service center for investigators, and our EDRAs engage in a variety of study-related activities including screening and enrolling patients, administering surveys, collecting bio-specimens, and making follow-up calls. Over the past two years, our program has averaged 222 enrollments/month (standard deviation = 79.93), gathering roughly 25 participants per study per month. Conclusion: Our EDRA model has consistently resulted in some of the highest number of enrollments across a variety of recently funded, multi-center studies. Maintaining a high-quality EDRA program requires continual investment on the part of the leadership team, though the benefits to investigators within and outside the department outweigh these costs. [West J Emerg Med. 2018;19(3)606-612.
Sampling Plans for Control-Inspection Schemes Under Independent and Dependent Sampling Designs With Applications to Photovoltaics
The evaluation of produced items at the time of delivery is, in practice,
usually amended by at least one inspection at later time points. We extend the
methodology of acceptance sampling for variables for arbitrary unknown
distributions when additional sampling infor- mation is available to such
settings. Based on appropriate approximations of the operating characteristic,
we derive new acceptance sampling plans that control the overall operating
characteristic. The results cover the case of independent sampling as well as
the case of dependent sampling. In particular, we study a modified panel
sampling design and the case of spatial batch sampling. The latter is advisable
in photovoltaic field monitoring studies, since it allows to detect and analyze
local clusters of degraded or damaged modules. Some finite sample properties
are examined by a simulation study, focusing on the accuracy of estimation
Evolutionary trajectories in rugged fitness landscapes
We consider the evolutionary trajectories traced out by an infinite
population undergoing mutation-selection dynamics in static, uncorrelated
random fitness landscapes. Starting from the population that consists of a
single genotype, the most populated genotype \textit{jumps} from a local
fitness maximum to another and eventually reaches the global maximum. We use a
strong selection limit, which reduces the dynamics beyond the first time step
to the competition between independent mutant subpopulations, to study the
dynamics of this model and of a simpler one-dimensional model which ignores the
geometry of the sequence space. We find that the fit genotypes that appear
along a trajectory are a subset of suitably defined fitness \textit{records},
and exploit several results from the record theory for non-identically
distributed random variables. The genotypes that contribute to the trajectory
are those records that are not \textit{bypassed} by superior records arising
further away from the initial population. Several conjectures concerning the
statistics of bypassing are extracted from numerical simulations. In
particular, for the one-dimensional model, we propose a simple relation between
the bypassing probability and the dynamic exponent which describes the scaling
of the typical evolution time with genome size. The latter can be determined
exactly in terms of the extremal properties of the fitness distribution.Comment: Figures in color; minor revisions in tex
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