Formation rates of Dark Matter Haloes

We derive an estimate of the rate of formation of dark matter halos per unit volume as a function of the halo mass and redshift of formation. Analytical estimates of the number density of dark matter halos are useful in modeling several cosmological phenomena. We use the excursion set formalism for computing the formation rate of dark matter halos. We use an approach that allows us to differentiate between major and minor mergers, as this is a pertinent issue for semi-analytic models of galaxy formation. We compute the formation rate for the Press-Schechter and the Sheth-Tormen mass function. We show that the formation rate computed in this manner is positive at all scales. We comment on the Sasaki formalism where negative halo formation rates are obtained. Our estimates compare very well with N-Body simulations for a variety of models. We also discuss the halo survival probability and the formation redshift distributions using our method.Comment: 30 pages, 9 figure

The ontogeny of kin recognition in tadpoles of the toadBufo melanostictus (Anura; Bufonidae)

The ontogeny of kin recognition and influence of social environment on the development of kin recognition behaviour was experimentally investigated in tadpoles of Bufo melanostictus that lived in aggregations and showed low larval dispersion. Embryos and tadpoles of the toad were reared as (i) kin only, (ii) with kin and non-kin (separated by a mesh screen), and (iii) in isolation. They were tested for the ability to discriminate between (i) familiar siblings and unfamiliar non-siblings, (ii) familiar siblings and familiar non-siblings and, (iii) unfamiliar siblings and unfamiliar non-siblings. All tadpoles were fed on boiled spinach before conducting trials. Preference of test tadpoles to associate near the end compartments whether empty or containing members of specific stimulus groups was assessed using a rectangular choice tank. When tested in tanks with empty end compartments, the test tadpoles showed random distribution and thus no bias for the apparatus or the procedure. In the presence of kin/non-kin in the end compartments a significantly greater number of test tadpoles spent the majority of the time near familiar or unfamiliar kin rather than near familiar or unfamiliar non-kin. Kin discrimination ability persisted throughout larval development. Familiarity with siblings is not required for discriminating kin from non-kin, and kin discrimination ability is not modified following exposure to non-kin. Also, involvement of dietary cues is unlikely to be the prime mechanism of kin recognition inB. melanostictus unlike in some other anurans

Density-dependent growth and metamorphosis in the larval bronze frog Rana temporalis is influenced by genetic relatedness of the cohort

Effects of density and kinship on growth and metamorphosis in tadpoles ofRana temporalis were studied in a 2x4 factorial experiment. Fifteen egg masses were collected from streams in the Western Ghat region of south India. The tadpoles were raised as siblings or in groups of non-siblings at increasing density levels, viz. 15, 30, 60 and 120/5 l water. With an increase in density level from 15 to 120 tadpoles/5 l water, duration of the larval stage increased and fewer individuals metamorphosed irrespective of whether they belonged to sibling or non-sibling groups by day 100 when the experiments were terminated. The size of individuals at metamorphosis declined significantly with increase in the density of rearing. However, at higher densities (60 and 120 tadpoles/5 l water) sibling group tadpoles performed better compared to mixed groups and took significantly less time to metamorphose. Also, more individuals of sibling groups metamorphosed compared to non-sibling groups at a given density. Mixed rearing retarded growth rates, prolonged larval duration resulting in a wider spectrum of size classes, and lowered the number of individuals recruited to terrestrial life. The study shows that interference competition occurred more strongly in cohorts of mixed relatedness than in sibling groups

Multiset filters

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Evaluation of critical value and urgent sample notification at clinical biochemistry laboratory in a tertiary care hospital

Background: Critical value and urgent sample result notification is widely accepted in the diagnostic fraternity as an important factor, as it may affect patient care and safety. Timely release and notification of these test result as per the individual laboratory protocol becomes an internal part of quality reporting system. The present study was aimed at evaluating the effective implementation of the existing protocol of urgent clinical notification (UCN) in the clinical biochemistry laboratory of tertiary care hospital and evaluating the turnaround time for urgent samples and critical results listed under UCN protocol in the clinical biochemistry laboratory.Methods: A prospective, observational study was conducted in clinical biochemistry laboratory of a tertiary care hospital. Descriptive statistics was calculated for all the data by Mann-Whitney and Wilcoxon test.Results: Majority of the critical results were informed to the clinical personnel by the clinical laboratory.  Out of 4687 critical results, 25.41% critical results were informed directly to the ward through telephonic communication. Documentation of critical values in the dedicated register and lab information system (LIS) was 25.41% and 40.28% respectively. 421 (9%) out of 4687 critical results were not notified. The median turnaround time for all urgent tests and critical results was found to be 72.33 minutes and 76.00 minutes respectively.Conclusions: This study highlighted various approaches to improve the critical value notification and its turnaround time and status of UCN in laborator

SARAS 2: A Spectral Radiometer for probing Cosmic Dawn and the Epoch of Reionization through detection of the global 21 cm signal

The global 21 cm signal from Cosmic Dawn (CD) and the Epoch of Reionization (EoR), at redshifts $z \sim 6-30$, probes the nature of first sources of radiation as well as physics of the Inter-Galactic Medium (IGM). Given that the signal is predicted to be extremely weak, of wide fractional bandwidth, and lies in a frequency range that is dominated by Galactic and Extragalactic foregrounds as well as Radio Frequency Interference, detection of the signal is a daunting task. Critical to the experiment is the manner in which the sky signal is represented through the instrument. It is of utmost importance to design a system whose spectral bandpass and additive spurious can be well calibrated and any calibration residual does not mimic the signal. SARAS is an ongoing experiment that aims to detect the global 21 cm signal. Here we present the design philosophy of the SARAS 2 system and discuss its performance and limitations based on laboratory and field measurements. Laboratory tests with the antenna replaced with a variety of terminations, including a network model for the antenna impedance, show that the gain calibration and modeling of internal additives leave no residuals with Fourier amplitudes exceeding 2~mK, or residual Gaussians of 25 MHz width with amplitudes exceeding 2~mK. Thus, even accounting for reflection and radiation efficiency losses in the antenna, the SARAS~2 system is capable of detection of complex 21-cm profiles at the level predicted by currently favoured models for thermal baryon evolution.Comment: 44 pages, 17 figures; comments and suggestions are welcom

CLOT PROMOTING AND DISSOLVING PROPERTIES OF CUCUMBER (CUCUMIS SATIVUS) SAP, VALIDATING ITS USE IN TRADITIONAL MEDICINE

Objective: To investigate the biochemical events that are associated with the skin softening, cleansing and wound healing properties of the cucumber (Cucumis sativus L) sap extract.Methods: Preparation of cucumber sap extract (CSE). Assay of CSE for proteolytic activity, plasma re-calcification time, APTT, PT, thrombin-like activity, plasmin-like activity, and effect on platelet aggregation and wound healing property by physical, biochemical and histological examinations. Appropriate positive and negative controls were maintained wherever necessary.Results: CSE decreased the plasma re-calcification time and prothrombin time (PT) and showed factor VII (pro-convertin) like activity. EGTA or EDTA pre-treated CSE did not alter the plasma recalcification time and PT. CSE readily hydrolyzed the plasma clot and azocasein; while, IAA pre-treated CSE did not hydrolyze the plasma clot and azocasein. CSE inhibited the agonists collagen, ADP and epinephrine induced platelet aggregation in PRP in the order epinephrine>collagen>ADP with the respective IC50 of 22 ± 2.5, 20 ± 3 and 11 ± 2 µg/ml. PMSF pre-treated but not IAA and EDTA pre-treated CSE lost the platelet aggregation inhibition property. Further, CSE augmented wound healing process including the scar removal in a mouse model. The SOD, CAT, GSH activities and hydroxyproline, hexosamine and hexuronic acid contents were increased while, NO, LPO and MPO activities were decreased compared to control values. Histological study revealed accelerated wound healing involving epithelialisation and re-formation of skin following CSE treatment compared to Neosporin.Conclusion: CSE contain metallo-, serine and cysteine proteases, and interfere in clot formation, dissolution and wound healing process, which validates the use of cucumber as cosmetics and to treat wounds by traditional healers.Â

A Pattern Based Approach to Defining the Dynamic Infrastructure of UML 2.0

The 2U Consortium has recently submitted a proposal for the definition of the UML 2.0 infrastructure. This uses an innovative technique of rapidly “stamping out” the definition using a small number of patterns commonly found in software architecture. The patterns, their instantiation, and any further language details are described using precise class diagrams and OCL, this enables the definition to be easily understood. The main focus of the 2U approach is on the static part of the definition. A further concern when modelling software, using languages such as the UML, is describing the dynamic behaviour of the system over time. The contribution of this paper is to provide a template that can be used to “stamp out” the dynamic part of the UML 2.0 infrastructure. We argue for the suitability of the dynamic template because it makes little commitment to concrete abstractions and can, therefore, be used to support a broad spectrum of behavioural languages