193 research outputs found
Haematology and biochemical parameters of different feeding behaviour of teleost fishes from Vellar estuary, India
Haematological parameters have been recognized
as valuable tools for monitoring fish health. Haematological
and serum biochemical parameters were studied and
compared different feeding behaviour of teleost fishes.
Three marine teleost fishes, Lates calcarifer (carnivores),
Mugil cephalus (omnivores) and Chanos chanos (herbivores),
were carried out in order to find out a normal range
of blood parameters which would serve as baseline data for
assessment of the health status of the fish as well as
reference point for future comparative surveys. Blood
parameters such as red blood cell count (RBC) and white
blood cells count (WBC), haemoglobin, haematocrit, mean
cell haemoglobin concentration (MCHC), mean cell volume
(MCV), mean cell haemoglobin, glucose, protein,
cholesterol and urea were estimated from teleost fishes of
different trophic level. Statistical analysis revealed that
differences in haematological parameters between marine
fish were significant (P<0.01)
Evaluation of normal variants of circle of Willis at MRI
Background: Anatomy of circle of Willis (COW) shows extensive variations in different individuals and signifies the causation and presentation of clinical disease. The present study aims to evaluate the different anatomical variations of the Circle of Willis (COW) in general population, using magnetic resonance (MR) 3D-time of flight angiography and to correlate the observations with age and gender characteristics.Methods: This observational clinical study was conducted January 2013 to March 2014 in 503patients who were referred for MRI – Brain. MRI (Philips 1.5 Tesla magnet) with routine brain sequences along with 3D –TOF MRA was done in all patients. The anatomical variants of the anterior and posterior components of the COW were studied. The complete COW was assessed and the diameters of all the components were measured. The correlation between the vessel diameters in relations to age and gender were evaluated.Results: The mean age group of study participants was 42 years. Male dominance was seen among participants (57.1%). The complete configuration of the circle was seen in 31.6% of population. Most common anterior variant is type A (normal anterior configuration) with a prevalence of 52.9% and posterior variant is type K with a prevalence of 32.9%. Average diameters of the proximal vessels supplying the COW were larger in the older age subjects (centripetal vessels, the right and left ICA s and BA). Statistically significant differences between the mean vessel diameters between males and females were seen in the ICA-RT, ICA-LT, and PCOA-LT.Conclusions: The present study showed great variability of the anatomy of the COW in asymptomatic person. Various variants of COW can be picked up by MRA which is safer and non-invasive when compared with CTA / DSA. Knowledge of these variations would help in planning surgical procedures as well as preventing unwanted interventions
The problem of programming language concurrency semantics
Despite decades of research, we do not have a satisfactory concurrency semantics for any general-purpose programming language that aims to support concurrent systems code. The Java Memory Model has been shown to be unsound with respect to standard compiler optimisations, while the C/C++11 model is too weak, admitting undesirable thin-air executions.
Our goal in this paper is to articulate this major open problem as clearly as is currently possible, showing how it arises from the combination of multiprocessor relaxed-memory behaviour and the desire to accommodate current compiler optimisations. We make several novel contributions that each shed some light on the problem, constraining the possible solutions and identifying new difficulties.
First we give a positive result, proving in HOL4 that the existing axiomatic model for C/C++11 guarantees sequentially consistent semantics for simple race-free programs that do not use low-level atomics (DRF-SC, one of the core design goals). We then describe the thin-air problem and show that it cannot be solved, without restricting current compiler optimisations, using any per-candidate-execution condition in the style of the C/C++11 model. Thin-air executions were thought to be confined to programs using relaxed atomics, but we further show that they recur when one attempts to integrate the concurrency model with more of C, mixing atomic and nonatomic accesses, and that also breaks the DRF-SC result. We then describe a semantics based on an explicit operational construction of out-of-order execution, giving the desired behaviour for thin-air examples but exposing further difficulties with accommodating existing compiler optimisations. Finally, we show that there are major difficulties integrating concurrency semantics with the C/C++ notion of undefined behaviour.
We hope thereby to stimulate and enable research on this key issue
Approximate reasoning for real-time probabilistic processes
We develop a pseudo-metric analogue of bisimulation for generalized
semi-Markov processes. The kernel of this pseudo-metric corresponds to
bisimulation; thus we have extended bisimulation for continuous-time
probabilistic processes to a much broader class of distributions than
exponential distributions. This pseudo-metric gives a useful handle on
approximate reasoning in the presence of numerical information -- such as
probabilities and time -- in the model. We give a fixed point characterization
of the pseudo-metric. This makes available coinductive reasoning principles for
reasoning about distances. We demonstrate that our approach is insensitive to
potentially ad hoc articulations of distance by showing that it is intrinsic to
an underlying uniformity. We provide a logical characterization of this
uniformity using a real-valued modal logic. We show that several quantitative
properties of interest are continuous with respect to the pseudo-metric. Thus,
if two processes are metrically close, then observable quantitative properties
of interest are indeed close.Comment: Preliminary version appeared in QEST 0
Chaperone-Mediated Protein Disaggregation Triggers Proteolytic Clearance of Intra-nuclear Protein Inclusions
The formation of insoluble inclusions in the cytosol and nucleus is associated with impaired protein homeostasis and is a hallmark of several neurodegenerative diseases. Due to the absence of the autophagic machinery, nuclear protein aggregates require a solubilization step preceding degradation by the 26S proteasome. Using yeast, we identify a nuclear protein quality control pathway required for the clearance of protein aggregates. The nuclear J-domain protein Apj1 supports protein disaggregation together with Hsp70 but independent of the canonical disaggregase Hsp104. Disaggregation mediated by Apj1/Hsp70 promotes turnover rather than refolding. A loss of Apj1 activity uncouples disaggregation from proteasomal turnover, resulting in accumulation of toxic soluble protein species. Endogenous substrates of the Apj1/Hsp70 pathway include both nuclear and cytoplasmic proteins, which aggregate inside the nucleus upon proteotoxic stress. These findings demonstrate the coordinated activity of the Apj1/Hsp70 disaggregation system with the 26S proteasome in facilitating the clearance of toxic inclusions inside the nucleus
Modeling and Reasoning over Distributed Systems using Aspect-Oriented Graph Grammars
Aspect-orientation is a relatively new paradigm that introduces abstractions
to modularize the implementation of system-wide policies. It is based on a
composition operation, called aspect weaving, that implicitly modifies a base
system by performing related changes within the system modules. Aspect-oriented
graph grammars (AOGG) extend the classic graph grammar formalism by defining
aspects as sets of rule-based modifications over a base graph grammar. Despite
the advantages of aspect-oriented concepts regarding modularity, the implicit
nature of the aspect weaving operation may also introduce issues when reasoning
about the system behavior. Since in AOGGs aspect weaving is characterized by
means of rule-based rewriting, we can overcome these problems by using known
analysis techniques from the graph transformation literature to study aspect
composition. In this paper, we present a case study of a distributed
client-server system with global policies, modeled as an aspect-oriented graph
grammar, and discuss how to use the AGG tool to identify potential conflicts in
aspect weaving
HLA-G Dimers in the Prolongation of Kidney Allograft Survival
Human leukocyte antigen-G (HLA-G) contributes to acceptance of allografts in solid organ/tissue transplantation. Most studies have determined that soluble HLA-G isoforms are systematically detected in serum/plasma of transplanted patients with significantly fewer episodes of acute and/or chronic rejection of allogeneic tissue/organ. Current models of the interactions of HLA-G and its specific receptors explain it as functioning in a monomeric form. However, in recent years, new data has revealed the ability of HLA-G to form disulfide-linked dimeric complexes with high preferential binding and functional activities. Limited data are available on the role of soluble HLA-G dimers in clinical pathological conditions. We describe here the presence of soluble HLA-G dimers in kidney transplant patients. Our study showed that a high level of HLA-G dimers in plasma and increased expression of the membrane-bound form of HLA-G on monocytes are associated with prolongation of kidney allograft survival. We also determined that the presence of soluble HLA-G dimers links to the lower levels of proinflammatory cytokines, suggesting a potential role of HLA-G dimers in controlling the accompanying inflammatory state
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