447 research outputs found
Biochemical correlates of cardiac hypertrophy. IV. Observations on the cellular organization of growth during myocardial hypertrophy in the rat
The mechanisms by which the DNA content of the heart increases following acutely induced cardiac hypertrophy were investigated in mature Sprague-Dawley rats. Special attention was given to the cellular organization of the growth process. Autoradiographic studies provided conclusive evidence that the uptake of tritiated thymidine is completely limited to nonmuscular cellular elements, chiefly connective tissue cells. The frequency of labeled nuclei was increased by sixfold during hypertrophy. The thymidine pool was not appreciably different in the hypertrophied hearts. Connective tissue nuclei formed a larger proportion of the total nuclear population in hypertrophied hearts, and their distribution was less uniform than in the normal heart. Quantitative histologic studies also showed that the total number of left ventricular muscle cell nuclei did not increase during hypertrophy but rather may have decreased slightly. Both the concentration and the total amount of hydroxyproline increased in parallel with the proliferative changes in the connective tissue and provide further supportive evidence to the autoradiographic and histologic studies
The blue supergiant Sher 25 revisited in the Gaia era
Aims. The evolutionary status of the blue supergiant Sher 25 and its
membership to the massive cluster NGC 3603 are investigated. Methods. A hybrid
non-LTE (local thermodynamic equilibrium) spectrum synthesis approach is
employed to analyse a high-resolution optical spectrum of Sher 25 and five
similar early B-type comparison stars in order to derive atmospheric parameters
and elemental abundances. Fundamental stellar parameters are determined by
considering stellar evolution tracks, Gaia Data Release 3 (DR3) data and
complementary distance information. Interstellar reddening and the reddening
law along the sight line towards Sher 25 are constrained employing UV
photometry for the first time in addition to optical and infrared data. The
distance to NGC 3603 is reevaluated based on Gaia DR3 data of the innermost
cluster O-stars. Results. The spectroscopic distance derived from the
quantitative analysis implies that Sher 25 lies in the foreground of NGC 3603,
which is found to have a distance of = 6250150 pc. A
cluster membership is also excluded as the hourglass nebula is unaffected by
the vigorous stellar winds of the cluster stars and from the different
excitation signatures of the hourglass nebula and the nebula around NGC 3603.
Sher 25 turns out to have a luminosity of log L/L = 5.480.14,
equivalent to that of a 27 supergiant in a single-star
scenario, which is about half of the mass assumed so far, bringing it much
closer in its characteristics to Sk-69{\deg}202, the progenitor of SN 1987A.
Sher 25 is significantly older than NGC 3603. Further arguments for a binary
(merger) evolutionary scenario of Sher 25 are discussed.Comment: 27 pages, 22 figures, Accepted for publication in Astronomy &
Astrophysics, Data: https://doi.org/10.5281/zenodo.823015
A polynomial oracle-time algorithm for convex integer minimization
In this paper we consider the solution of certain convex integer minimization
problems via greedy augmentation procedures. We show that a greedy augmentation
procedure that employs only directions from certain Graver bases needs only
polynomially many augmentation steps to solve the given problem. We extend
these results to convex -fold integer minimization problems and to convex
2-stage stochastic integer minimization problems. Finally, we present some
applications of convex -fold integer minimization problems for which our
approach provides polynomial time solution algorithms.Comment: 19 pages, 1 figur
A Computation of the Maximal Order Type of the Term Ordering on Finite Multisets
We give a sharpening of a recent result of Aschenbrenner and Pong about the maximal order type of the term ordering on the finite multisets over a wpo. Moreover we discuss an approach to compute maximal order types of well-partial orders which are related to tree embeddings
A polynomial-time algorithm for optimizing over N-fold 4-block decomposable integer programs
In this paper we generalize N-fold integer programs and two-stage integer
programs with N scenarios to N-fold 4-block decomposable integer programs. We
show that for fixed blocks but variable N, these integer programs are
polynomial-time solvable for any linear objective. Moreover, we present a
polynomial-time computable optimality certificate for the case of fixed blocks,
variable N and any convex separable objective function. We conclude with two
sample applications, stochastic integer programs with second-order dominance
constraints and stochastic integer multi-commodity flows, which (for fixed
blocks) can be solved in polynomial time in the number of scenarios and
commodities and in the binary encoding length of the input data. In the proof
of our main theorem we combine several non-trivial constructions from the
theory of Graver bases. We are confident that our approach paves the way for
further extensions
Utility of an attention-based performance validity test for the detection of feigned cognitive dysfunction after acquired brain injury
Introduction: The Groningen Effort Test (GET) is a recently developed performance validity test (PVT) for the identification of noncredible performance in a neuropsychological assessment of attention abilities. Because the majority of already established PVTs are based on memory functions, the GET has the potential to make a valuable contribution to validity testing.Method: The current study examined the utility of the GET in the detection of feigned cognitive dysfunction after acquired brain injury (ABI) and its incremental validity over already established PVTs, namely the Test of Memory Malingering (TOMM), the Dot Counting Test (DCT), and the b Test. Three hundred and forty-eight participants took part in this study, including 58 patients with ABI (stroke or traumatic brain injury), 43 healthy individuals instructed to show normal behavior, and 247 healthy individuals instructed to feign cognitive dysfunction after ABI.Results: With excellent overall classification accuracy, the GET performed close to the level of the TOMM, and superior to the b Test and DCT. Data analyses further revealed that the GET provides additional diagnostic accuracy compared to the b Test and the DCT in the detection of feigned cognitive dysfunction, but has no incremental validity over the TOMM. For each of the four PVTs in this study, diagnostic sensitivity was independent of the simulation strategy used.Conclusions: It is concluded that the GET is an attention-based PVT with promising test characteristics and high diagnostic accuracy in the detection of noncredible cognitive performance using a simulation design. Given the results can be replicated in studies using known-groups methodology, it may be a useful tool for clinical practice to complement neuropsychological assessments of patients with ABI
Adaptive Evolution of the Myo6 Gene in Old World Fruit Bats (Family: Pteropodidae)
PMCID: PMC3631194This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Conservation Learning Initiative: Learn from evidence. Improve Conservation
The conservation community needs smarter and more successful actions to improve the impact of its work. For example, it is not always clear how to create training programmes that improve performance in a lasting way, or what the ingredients of a successful conservation partnership are, or how donors can set up funding so that grantees can work in a strategic and sustainable way.One way of designing successful, effective actions is through using insights from evidence-based learning. Recent years have seen significant steps forward in developing concepts for defining and using evidence in conservation. In late 2021, the MAVA Foundation, Foundations of Success (FOS), and Conservation Evidence joined forces in an initiative to build further on this work.Combining the strengths of their approaches with MAVA's treasure of nearly 30 years of conservation data, they set out to formulate assumptions and collect evidence to answer key learning questions. The results of this joint work are now available on the Conservation Learning Initiative website (https://conservation-learning.org/) and in a consolidated report.The website and report present:A practical 5-step approach for evidence-based learning in conservation, designed for combining different sources of evidence, dealing with differences in reliability and relevance, and drawing conclusions.Valuable insights based on data regarding four widely used conservation strategies: capacity-building, forming partnerships and alliances, providing flexible funding, and research and monitoring.The lessons learned will help conservationists fine-tune their work or investment to increase their conservation impact. By applying the approach on their own data, they can learn from evidence to make better decisions and improve strategies over time
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