The Spherically Symmetric Gravitational Collapse of a Clump of Solids in a Gas

Several mechanisms have been identified that create dense particle clumps in the solar nebula. The present work is concerned with the gravitational collapse of such clumps, idealized as being spherically symmetric. Calculations using the two-fluid model are performed (almost) up to the time when a central density singularity forms. The end result of the study is a parametrization for this time, in order that it may be compared with timescales for various disruptive effects to which clumps may be subject. An important effect is that as the clump compresses, it also compresses the gas due to drag. This increases gas pressure which retards particle collapse and leads to oscillation in the size and density of the clump. The ratio of gravitational force to gas pressure gives a two-phase Jeans parameter, $J_t$, which is the classical Jeans parameter with the sound speed replaced by an the wave speed in a coupled two-fluid medium. Its use makes the results insensitive to the initial density ratio of particles to gas as a separate parameter. An ordinary differential equation model is developed which takes the form of two coupled non-linear oscillators and reproduces key features of the simulations. Finally, a parametric study of the time to collapse is performed and a formula (fit to the simulations) is developed. In the incompressible limit $J_t \to 0$, collapse time equals sedimentation time. As $J_t$ increases, the collapse time decreases roughly linearly with $J_t$ until $J_t \gtrsim 0.4$ when it becomes approximately equal to the dynamical time

A note on leapfrogging vortex rings

In this paper we provide examples, by numerical simulation using the Navier-Stokes equations for axisymmetric laminar flow, of the 'leapfrogging' motion of two, initially identical, vortex rings which share a common axis of symmetry. We show that the number of clear passes that each ring makes through the other increases with Reynolds number, and that as long as the configuration remains stable the two rings ultimately merge to form a single vortex ring

A study on antimicrobial sensitivity pattern in Neisseria gonorrhoeae in a tertiary care hospital

Background: Sexually transmitted diseases are prevalent throughout the world. Sexually transmitted diseases (STD) play a major role in the transmission of HIV infection. The risk of acquiring HIV infection in non-ulcerative STD is 3 to 5 times more than that in persons without any sexually transmitted infections. One of the main non-ulcerative STD is gonorrhoea. The relative incidence of gonococcal infections is about 10 to 13% of total sexually transmitted infections in STD clinics. Aims and objectives was to identify gonococcal infection in patients attending the STD clinic and associated sexually transmitted infections and to study the antimicrobial susceptibility of gonococcus and to modify the disease intervention strategies.Methods: A retrospective study was conducted in our institute of venereology, government general hospital and madras medical college, Chennai-03, Tamil Nadu, India. 43 patients with gram stained smear or culture positive for gonococcus who attended the institute from February 2013 to September 2014 were taken into the study. All the details were collected from the case records of the patients. The antibiotic sensitivity testing in N. gonorrhoeae had been done by Kirby-Bauer disc diffusion method. Screening for other sexually transmitted diseases had been done and were treated according to the institute guidelines.Results: Specimens from 43 patients (40 male, 3 females) had been collected. 40 specimens were found to be culture positive. Antibiotic sensitivity tests were carried out on those 40 isolates of Neisseria gonorrhoeae obtained in pure culture. 70% of isolates were resistant to penicillin and 30% were less sensitive to it. 52.5% of the isolates were PPNG. 57.5% of isolates were resistant to ciprofloxacin and 42.5% were less sensitive to it. 7.5% were resistant to ceftriaxone, 12.5% were resistant to cefixime and 15% were resistant to spectinomycin. All the isolates were sensitive to Azithromycin. Three male patients had HIV (6.9%), three had syphilis and one had genital wart. One female patient had trichomoniasis.Conclusions: The results of the study indicate that multidrug resistant Neisseria gonorrhoeae is prevalent in this region. Associated STDs must be investigated to prevent the transmission of HIV and further complications. The need for establishing a national surveillance programme for antibiotic resistance becomes clear with this study

Seborrhoeic keratosis with autosomal dominant inheritance - a rare case report

Seborrhoeic keratosis is a benign tumour composed of epidermal keratinocytes, displaying varying morphological features, frequently pigmented and more common in the elderly. Various clinical and histopathological variants have been described. A genetically determined predisposition to Seborrhoeic keratosis is largely accepted. We report a case of multiple Seborrhoeic keratoses of childhood onset and transmitted for three generations in her family members as an autosomal dominant trait

Microfinance: Viable Approaches for Islamic Banking Implementation

Islamic banks have very much engaged in debt financing businesses the same way and as much as their conventional counterparts do. Debt financing businesses, as widely implemented, were specifically targeted for and tailored to the needs of middle and upper income group of people. The low income people remain left out and forgotten in most banking businesses while microfinance instruments, which are meant to help the poor and needy, remain unpopular among the banking institutions. There is indeed increasing calls for Islamic banks to seriously consider this type of instrument as part of their religious obligation embedded under their Islamic identity. This paper demonstrated that microfinance instruments are viable for Islamic banks to consider despite the claims that the contracts are less secured and hence, too risky to embark in. A number of microfinance instruments based on Islamic concepts namely Musyarakah, Murabahah, Mudharabah, Ijarah and Qard al-Hassan as well as operational frameworks such as SPV and wakalah, were being proposed and discussed to pave ways for its implementation by the Islamic banks

The effectiveness of multilevel classification system for Sport psychology (MCS-SP) model for athletes performance functional evaluation

This study attempted to distinguish issues and athletes’ problem into the category of performance function based on Multilevel Classification System for Sport Psychology (MCS-SP). In this study, athletes’ performance function were devided into Performance Development (PD) (n=54) and Performance Dysfunction (Pdy) (n=43). Using Five Facet Mindfulness Questionnaire (FFMQ) and Young Schema Questionnaire (YSQ-S3), the overall level of mindfulness skills and thinking schemes were moderate. PD athletes were standingout significantly in mindfulness skills and few elements of thinking schemes such as self-sacrificing, unrelenting standards, and entitlement. Meanwhile, Pdy athletes were more likely to be in other side of thinking schemes elements. It can be seen that MCS-SP can be used as a standard reference for identifying athletes’ performance functional status and planning for better psychological interventions.Keywords: Multilevel Classification System for Sport Psychology (MCS-SP), PerformanceFunction, Performance Development (PD), Performance Dysfunction (Pdy), MASUM athlet

Antimicrobial activity of Rauvolfia tetraphylla and Physalis minima leaf and callus extracts

The in vitro antimicrobial activity of Rauvolfia tetraphylla and Physalis minima leaf and callus extracts were studied against selected pathogenic fungi and bacteria, following broth dilution assay. Leaves and calli were extracted using absolute alcohol, benzene, chloroform, methanol and petroleum ether. Among the five solvents used, leaf and callus extracted in chloroform of both the plants were found to be more effective against pathogenic bacteria and fungi, where the minimum inhibitory concentration (MIC) ranged between 0.25 to 6 mg/ml. Absolute alcohol extracts showed MIC of 0.25 to 4 mg/ml forbacteria, whereas for fungi it ranged from 0.25 to 100 mg/ml. Extracts of benzene and petroleum ether were ineffective in inhibiting the bacterial and fungal growth or showed poor inhibition. Methanol extract showed MIC of 0.25 to 100 mg/ml against bacterial pathogens and 0.5 to 100 mg/ml againstfungal pathogens. The antimicrobial activities of these two indigenous medicinal plants were discussed in the present pape

Basal cell carcinoma- a prospective clinico epidemiological and pathological study

Background: Basal cell carcinoma is the most common malignant tumour of the skin worldwide. The objective was to find out the age and sex incidence of basal cell carcinoma in patients attending the outpatient department of dermatology and to find out the various clinical and histopathological features of basal cell carcinoma.Methods: It was a prospective observational study carried out in a tertiary care hospital, Chennai, Tamilnadu, India. Patients with clinical diagnosis of basal cell carcinoma were included in the study after thorough history, clinical examination, routine and special investigations like skin biopsy.Results: Out of 20 patients with basal cell carcinoma 6 were males and 14 were females with a male to female ratio of 1:2.33. Most commonly affected age group was 50-70 years (70%). Distribution of BCC in our study was confined to head and neck area. Most common morphological subtype encountered in this study was nodular/nodulo-ulcerative BCC (70%), followed by pigmented type (25%) and superficial BCC (5%). The most common histological variant observed in present study was nodular type (55%), followed by pigmented variant (25%), adenoid (5%), basisquamous (5%), superficial BCC (5%) and BCC with sebaceous differentiation (5%).Conclusions: This study highlights a paradoxically increasing trend of BCC with female predilection. Early detection and treatment of lesions are crucial to decrease the functional and cosmetic disfigurement and also this study highlights the importance of improving awareness among general practitioners, public health workers and general population

Clinico-epidemiological study of stasis eczema

Background: This study was done to determine the epidemiological aspects of stasis eczema and the association of various risk factors of the disease in the local population.Methods: This cross-sectional study was done at a tertiary hospital in southern India over a period of 1 year. Epidemiological and clinical data of stasis dermatitis patients above 20 years of age were recorded. Data was tabulated and analyzed using Microsoft excel software.Results: Of the study population of 120 prevalence is found to be highest in the age group of 50 to 60 years (42.5%) and males are more commonly affected. Occupation involving prolonged standing or sitting and lack of exercise activity is found to be a significant risk factor. The commonest skin finding in present study is eczema (80%). The most common complication was ulcer which was seen in 12.5% of our patients. Reticular veins are the most common dilated veins seen in our patients. About 70% of patients in present study fall under C4a stage of CEAP classification. About one half of symptomatic patients in present study (53.3%) had no radiological evidence of incompetent veins. Among patients with valvular incompetence, perforator veins were most commonly found to be incompetent (62.5%) followed by involvement of the saphenous venous system (23.2%).Conclusions: The study confirms the importance of environmental factors in the development of stasis eczema. There is a ten-fold higher prevalence of the disease in men in our population compared to previous studies which invariably reports a female preponderance

The Role of the Fc Region in CD70-specific Antibody Effects on Cardiac Transplant Survival

Background: The role of the CD70-specific antibody and the mechanisms by which it extends transplant survival are not known. Methods: Fully major histocompatibility complex-mismatched heterotopic heart transplantation (BALB/c to C57BL/6) was performed. Treated mice received intraperitoneal injections of wild-type (WT) CD70-specific antibody (FR70) or IgG1 or IgG2a chimeric antibodies on days 0, 2, 4, and 6 posttransplantation. Results: WT FR70 antibody significantly extended heart transplant survival to 19 days compared with untreated mice (median survival time [MST]=10 days). Graft survival using the nondepleting IgG1 antibody was significantly shorter (MST=14 days), whereas the survival using depleting IgG2a antibody (MST=18) was similar to that using WT FR70. The FR70 and IgG2a antibodies demonstrated a greater efficiency of fixing mouse complement over the IgG1 variant in vitro. CD4 and CD8 T-cell graft infiltration was reduced with treatment; however, this was most pronounced with WT FR70 and IgG2a antibody therapy compared with the IgG1 chimeric variant. Circulating donor-specific IgG alloantibodies were initially reduced with WT FR70 treatment (day 8 posttransplantation) but increased at days 15 and 20 posttransplantation to the level detected in untreated controls. Conclusion: We conclude that WT (FR70) and the IgG2a depleting variant of CD70-specific antibody reduce graft infiltrating CD4 and CD8 T cells, transiently reduce serum alloantibody levels, and extend graft survival. In contrast, the nondepleting IgG1 variant of this antibody showed lower efficacy. These data suggest that a depleting mechanism of action and not merely costimulation blockade plays a substantial role in the therapeutic effects of CD70-specific antibody