2,856 research outputs found
Persistence in One-dimensional Ising Models with Parallel Dynamics
We study persistence in one-dimensional ferromagnetic and anti-ferromagnetic
nearest-neighbor Ising models with parallel dynamics. The probability P(t) that
a given spin has not flipped up to time t, when the system evolves from an
initial random configuration, decays as P(t) \sim 1/t^theta_p with theta_p
\simeq 0.75 numerically. A mapping to the dynamics of two decoupled A+A \to 0
models yields theta_p = 3/4 exactly. A finite size scaling analysis clarifies
the nature of dynamical scaling in the distribution of persistent sites
obtained under this dynamics.Comment: 5 pages Latex file, 3 postscript figures, to appear in Phys Rev.
Diffuse Reflectance Spectra of Coals in the UV-Visible and Near-IR Regions
Chemical leaching of sub-bituminous coal with inorganic and organic leachants has been monitored by the UV-Visible and Near-IR spectra with the diffuse reflectance method. The shape and intensity of the observed absorption bands changed with leaching, reflecting the solubilization of the aromatic molecules and the degree of the intermolecular interaction between organic and inorganic phases. The absorption maximum of benzene-oxygen system was found between 235-270 nm and is showing a red shift with leaching. The characteristic naphthalene ring systems (220 & 280 nm) are masked by the absorption regions of monoaromatic rings; indicating the content of napthalenoid hydrocarbon is very low. The bands observed in the visible region (450nm) is attributed to S02 in the sample and with leaching this band is showing a red shift. The weak bond of the 680 nm is attributed to the ∏-∏* electronic transitions of the polynuclear aromatic hydrocarbons which shows red shift with leaching
On The Center Sets and Center Numbers of Some Graph Classes
For a set of vertices and the vertex in a connected graph ,
is called the -eccentricity of in
. The set of vertices with minimum -eccentricity is called the -center
of . Any set of vertices of such that is an -center for some
set of vertices of is called a center set. We identify the center sets
of certain classes of graphs namely, Block graphs, , , wheel
graphs, odd cycles and symmetric even graphs and enumerate them for many of
these graph classes. We also introduce the concept of center number which is
defined as the number of distinct center sets of a graph and determine the
center number of some graph classes
Spatial distribution of persistent sites
We study the distribution of persistent sites (sites unvisited by particles
) in one dimensional reaction-diffusion model. We define
the {\it empty intervals} as the separations between adjacent persistent sites,
and study their size distribution as a function of interval length
and time . The decay of persistence is the process of irreversible
coalescence of these empty intervals, which we study analytically under the
Independent Interval Approximation (IIA). Physical considerations suggest that
the asymptotic solution is given by the dynamic scaling form
with the average interval size . We show
under the IIA that the scaling function as and
decays exponentially at large . The exponent is related to the
persistence exponent through the scaling relation .
We compare these predictions with the results of numerical simulations. We
determine the two-point correlation function under the IIA. We find
that for , where , in agreement
with our earlier numerical results.Comment: 15 pages in RevTeX, 5 postscript figure
Clinical, etiological and laboratory profile of febrile thrombocytopenia and correlation of platelet count with outcome in a South Indian tertiary hospital
Background: Febrile thrombocytopenia is commonly encountered by doctors especially during monsoon and peri-monsoon period, many of these patients have a turbulent cthisse with multi organ dysfunction and might land up in ICU with significant morbidity and mortality. Infections are the commonest causes of thrombocytopenia and they vary with season and geographical location. A systematic approach, carried out with an awareness of causes, clinical presentation and laboratory profile of febrile thrombocytopenia can shorten the duration of investigations and bring out the diagnosis early, reducing morbidity and mortality of patients and reducing burden on hospital resthisces. The objective of the study is to study the underlying etiology, the various clinical presentations, laboratory profile and complications of fever with thrombocytopenia in this community during monsoon period and to correlate thrombocytopenia with outcome, co morbidities and its etiology.Methods: The prospective observational study was conducted in tertiary centre in Kolar between June-December 2017. Patients meeting inclusion and exclusion criteria were grouped into 4 groups based on platelet counts, and correlated with comorbidities, etiology and outcome. Detailed clinical and laboratory examination were done in all patients and p value of <0.05 was considered statistically significant.Results: Among 465 patients were included in the study. Dengue was the most common cause for febrile thrombocytopenia and mortality. Hepatic complications and petechiaes were the most common complications and bleeding manifestations. 135 patients received platelet transfusion but there was no relationship between platelet transfusion and outcome, there were 9 deaths in the study and there was no association between death and platelet count at admission.Conclusions: There was no relation between platelet count on admission and mortality and also there was no relationship between platelet transfusion and outcome. Knowing the clinical presentation, etiology, complications and its monitoring can significantly reduce the morbidity and mortality due to febrile thrombocytopenia
Anti-ulcer activity of arachidonic acid (PUFA) oils in different induced ulcer animal models
Background: Ulcers of the lower part of the oesophagus, the stomach and the first part of the duodenum are also known as peptic ulcers. Peptic ulcers can affect people of any age, but they are more common as you get older. There is a focus on research for better tolerated and efficacious anti-ulcer agents.Methods: Effect of anti-ulcer activity of fish oil and Arasco oil was evaluated in different animal models of ulcers i.e. ethanol induced, water immersion and pyloric ligation techniques. The Superoxide dismutase activity in gastric tissue was also ascertained in two groups of animals. The animals received either fish oil (40 µl, PO), Arasco oil (40 µl, PO), omeprazole (20 mg/kg PO) or ranitidine (30 mg/kg PO). The gastro-protection was calculated based on ulcer index, pH and gastric juice volume.Results: The results of this study suggest that poly unsaturated fatty acid (PUFA) contained in fish oil and Arasco oil have moderate anti-ulcer activity although probably lesser in potency than the available anti-ulcer drugs like omeprazole and ranitidine.Conclusion: These results have shown that PUFA containing oils provided moderate gastrointestinal protection in all the induced ulcer models employed. Thus it can be concluded that PUFA containing oils like the Fish oil and Arasco oil have anti-ulcer properties and the mechanisms involved in these actions need to be investigated.
Rhodamine-B labeled peptide hormone evaluation by thin layer chromatography
A novel thin layer chromatographic procedure was devised to evaluate the activity of rhodamine-B tagged peptide hormone such as vasopressin & octreotide. Peptide hormones viz. octreotide and vasopressin were added with rhodamine-B (0.2 ml of concentration 2.5mg/ml) and were estimated through thin layer chromatography (TLC) in a concentration and time dependent manner i.e. 25μg, 50μg for 30 & 60 minutes and 4.8μg, 9.6μg for 30 & 60 minutes respectively. The solvent medium used was a mixture of butanol, acetic acid and water in a ratio of 4:1:1. Stationary phase used in this experiment was Silica gel mixed with an inert binder like calcium sulphate and water. Different peptides travel at different rates due to the differences in their attraction to the stationary phase and because of difference in solubility in the solvent. The plates were made to visualize under a UV detector and respective Rf values were calculated. Results showed that rhodamine-B tagged peptides were well seen under UV detector as well as with naked eyes and is an efficacious marker when compared with other developing systems such as ninhydrin, iodine spray etc
Tillage and Mulching Effects on Crop Productivity and Moisture Dynamics in Fodder Sorghum Based Cropping Systems under Rainfed Condition
Indian farmers generally take more than one crop in a year to maximize their total production and profits. In this process fodder sorghum followed by crops like chickpea, wheat, oat, barley and mustard are common in Bundelkhand region of central India. The soils of Budelkhand region of India are medium to low in fertility with low organic matter content and poor water holding capacity that limits the fodder and food productivity. Therefore, adoption of resource conserving technologies in fodder sorghum based cropping systems under rainfed conditions is one of the potential areas, where increase in green fodder and food production with enhanced resource use efficiency can be achieved (Dixit et al., 2014). Adoption of resource conserving technologies includes minimal soil disturbance, maintaining soil cover and crop diversification through conservation of moisture for which the role of green manure mulches has been well recognised. Under rainfed situation, moisture stress has been identified as one of most important factor limiting yield of post rainy season crop. Introducing conservation tillage (zero tillage/reduced tillage) along with foliage mulching may improve soil moisture conservation, weed control, soil physic-chemical and biological properties, system productivity and may also reduce fuel, animal or human energy required for land preparation
Significance of APTT as early predictor of bleeding in comparison to thrombocytopenia in dengue virus infection
Background: Dengue is a systemic viral infection transmitted by mosquitoes such as Aedes aegypti or Aedes albopictus. Dengue Fever (DF) is characterized by fever, headache, muscle or joint pain, and rash. The spectrum of dengue virus infection spreads from an undifferentiated fever and dengue fever (DF) to dengue haemorrhagic fever (DHF) with shock. Factors responsible for bleeding manifestations in dengue are vasculopathy, thrombocytopenia, coagulopathy, and disseminated intravascular coagulation (DIC). Coagulopathy results in derangement of activated partial thromboplastin time (APTT) which is an indicator of impending bleeding risk.Methods: A prospective study was conducted from June to December in 2017 in R L Jalappa Hospital. Patients aged above 18 years with febrile thrombocytopenia who are positive for dengue virus serology (NS1Ag and/ or IgM) were included in the study. Serial daily monitoring of platelet count and analysis of APTT levels were done. APTT was considered abnormal if it was more than 33.8s. Patients were followed up for evidence of leaking and bleeding manifestations.Results: Out of 170 patients 28.1% patients had bleeding manifestations. Bleeding signs were seen on clinical examination in 52.37% of patients. capillary leak was found in the form of Pleural effusion in 35.3%, Ascites in 41.2% and Periorbital edema in 31.2% of patients. Elevated APTT levels were seen in 110(64.7%) patients. Among patients with abnormal APTT platelet transfusion was done in 78.9% of patients, and among those with normal APTT levels platelet transfusion was done in 21.1% of patients.Conclusions: Our study showed significant correlation between bleeding manifestations and prolonged APTT levels as well as thrombocytopenia with abnormal APTT levels. Study concluded that 21.1% of platelet transfusions could have been prevented considering prolonged APTT as a predictor of bleeding manifestation, thus saving the resources and reactions due to platelet concentrate transfusion
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