Mathematical and Optimization Analysis of a Miniature Stirling Cryo-cooler

In the given report, a comprehensive analytical model of the working of a miniature Stirling Cyo-cooler is presented. The motivation of the study is to determine the optimum geometrical parameters of a cryo-cooler such as compressor length, regenerator diameter, expander diameter, and expander stroke. In the first part of the study, an ideal analysis is carried out using the Stirling Cycle and basic thermodynamics equations. Using these equations, rough geometrical parameters are found out. In the second part of the study, a more comprehensive Schmidt’s analysis is carried out. In this analysis, pressure and volume variations are considered sinusoidal and based on these, various equations regarding efficiency and COP are derived. Various graphs are generated in MATLAB plotting Refrigeration and Work done w.r.t to various geometrical parameters. With the help of these graphs, the net refrigeration obtained is calculated for a given geometry of cryo-cooler.. This model provides a more accurate picture of the cryo-cooler. However in this analysis, regenerator efficiency is considered 100 % which is not true in practical cases. In the third and final part of the study, optimization of regenerator is carried out. This part is based on Ackermann’s analysis in which various looses taking place inside a regenerator are considered and accounted for. These looses are minimized using an iterative cycle and optimum regenerator dimensions are obtained. Thus the geometrical results obtained from the third part of the study are expected to be most accurate as it accounts for most of the looses taking place inside a cryo-cooler

Narasimham Committee Report - Some Further Ramifications and Suggestions

This paper while agreeing with the general thrust of the Narasimham Committee Report. Calls attention to some logical corollaries of the Report and analyses some possible fallout from implementing the Report. We agree with the view that control of banking system should be under an autonomous body supervised by the RBI. However at the level of individual banks, closer scrutiny of lending procedures may be called for than is envisaged in the Report. In a freely functioning capital market the potential of government bonds is enormous, but this necessitates restructuring of the government bond market. The government bonds may then also be used as suitable hedging mechanisms by introducing options and futures trading. We recommend freeing up the operation of pension and provident fund to enable at least partial investment of such funds in risky securities. In the corporate sector, we believe that the current 2:1 debt equity norm is too high and not sustainable in the long term. We envisage that high debt levels and higher interest rates, combined with higher business risk may result in greater incidence of corporate sickness. This may call for various schemes for retrenched workers and amendment to land laws for easy exit of companies. On account of interdependencies across different policies, any sequencing of their implementation may be highly problematic. We therefore suggest a near simultaneity in the implementation of various reforms in order to build up a momentum which would be irreversible if people are to have confidence that the reforms will endure, and if we are to retain our credibility with international financial institutions.

Placental abruption: a persisting killer

Background: Placental abruption, common disorder in obstetric practice, enigma too, is uniquely fraught with dangers to mother baby. Objectives of study were to study trends of placental abruption, risk factors, management strategies to learn more for reduction in morbidity-mortality of mother-baby, even with low resources, also get insight for future research.  Methods: Records of cases of placental abruption managed over 27 years (between 1985 to 2011) were divided into three yearly blocks, A to I and analysed. Details  including operative procedures like dilatation-curettage, Caesarean Section (CS) or Ante-Partum Haemorrhage (APH) in past, disorders like chronic hypertension, threatened abortion, pregnancy specific hypertension, diabetes, anaemia in index pregnancy, management done maternal-neonatal outcome were analysed using stata 6 software.Results: There were 66,459 births during analysis period with 667 cases of placental abruption, 1% births, increasing trends from, 0.73% between 1985-1987 to, 1.11% in 2009-2011. In these 667 cases of placental abruption, 211 (32.5%) perinatal deaths occurred. Ratio of perinatal deaths due to placental abruption to overall perinatal deaths increased from 2.12% (8 cases) between 1985-1987 (Block A) to 5.12% (37 cases) between 2009-2011 (Block I). Case fatality in cases of placental abruption has been fluctuating between 3 to 5% till 2004, contributing to around 12-15%, maternal mortality, with no fatality in last 7 years.Conclusions: Cases of placental abruption have been increasing with no obvious reason. In recent past maternal deaths could be prevented but perinatal deaths, have been persisting actually more in last decade

Bilateral superficial ulnar artery with high origin from the axillary artery: its anatomy and clinical significance

The superficial ulnar artery (SUA) is a rare anatomical variant that usually arises either in the axilla or the arm and runs a superficial course in the forearm, enters the hand, and participates in the formation of superficial palmar arch. During the routine dissection of cadavers in the department of anatomy, whilst preparing the specimen for medical students, an unusual bilateral branch of the axillary artery was found in one of the cadavers: a rare variant of the artery known as SUA, which originates from the 2nd part of the axillary arteries of both sides. The SUA is a known anatomical variant, but the bilateral high origin from the 2nd part of the axillary artery is extremely unusual. Its occurrence is of great clinical importance to the surgical and radiological departments

Maternal Serum Insulin in Hypertensive Disorders of Pregnancy and Neonatal Outcome

Background: Complications of hypertensive disorders, during pregnancy (HDP), labour, postpartum have been recognized for centuries. Focus has shifted from maternal to materno-neonatal outcome, because effects of HDP on maternal metabolism have significant impact on perinatal outcome. Possibility of linkage of hyperinsulinemia leading to hypoglycaemia, growth retardation is real. Objective: Study was conducted to know relation of maternal serum insulin to the severity of hypertensive disorders and its effects on neonatal outcome.Material methods: Case control study was carried out over two years. Fasting blood sugar, insulin, post glucose blood sugar were estimated.Results: Overall 13.32% women who delivered during study period had HDP. Of these 964 women, 609(63.17%) had mild HDP, 12 (1.97%) of them had elevated insulin, 9 (75%) of 12 had LBW, [(2 neonatal deaths, 4(33.33%) still births, 3(25%) admitted to neonatal intensive care NIC)]. Eighty three (8.6%) had severe HDP, 12(14.45%) of them had elevated serum insulin, 8 (66.33%) of 12 had LBW babies (2 NND, 2 still births, one admitted to NIC), significant (p<0.001) difference from 71 with severe HDP with normal insulin. One hundred eight (11.2%) had mild preeclampsia, 21(19.44%) with elevated insulin, [17 (81%) of 21 had LBW babies, 4 (19.04%) NND, 3(14.28%) admitted to NIC, one (4.76%) septicemia. 9 (42.85%) still born, perinatal loss significantly higher (p<0.001), than 87 with mild preeclampsia and normal insulin. One hundred fifteen (11.9%) women had severe PE, 52(45.21%) had elevated serum insulin, 16(30.76%) LBW babies, 13(25%) still births, 13 (25%) babies admitted to NIC, one of 13 (1.92%)died (LBW), difference (significant (p<0.05) from 63 severe PE with normal insulin. Fourty nine (5.08%) women had eclampsia, 24 (48.97%) of them had elevated insulin, of them 7 (29.16%) had LBW, 13(54.16%) still births, 13 (54.16%) admitted to NIC, one (4.16%) NND, significantly more than in 25 with normal insulin (p<0.02). In HDP maternal insulin levels correlated significantly with perinatal outcome irrespective of severity of HDP.Conclusion: While there was linkage of maternal serum insulin to the severity of HDP, the change in the insulin level affected the perinatal outcome more than the severity of HDP

Государственная собственность и эффективность деятельности компании: оценка деятельности дезинвестированных предприятий государственного сектора

The Indian government devised a flexible method to modify the performance of public sector firms through disinvestment in the 1990s to boost commercial strength and bridge the budget deficit. The disinvestment policy intends to reduce the government’s involvement in the country’s economic activities to encourage the private sector. The research aims to empirically examine the financial and operating performance of thirty-two Central public sector enterprises (CPSEs) in India. Further, the paper intends to study the other firm factors that influence the performance parameters. The Wilcoxon signed-rank test and random panel regression model are the methods employed to analyze the data statistically. The results show that the profitability of disinvestment has not brought significantly much improvement post-privatization in PSEs. In contrast, the productivity of employees has improved. Dividend payout ratio and no. of employees have shown improvement after five years of disinvestment, and leverage has insignificantly declined. In addition, state ownership shows a significant negative relationship with the performance variables. It implies that higher the equity shareholding of the government (state ownership) in the CPSEs, would negatively hamper the performance of firms. On the other hand, GDP and firm size are positively affecting the profitability and productivity of employees. The study concludes that the government is required to bring down the equity shareholdings in CPSEs, directing more efforts towards strategic disinvestment. Government should choose strategic disinvestment rather than partial and small-scale disinvestment because neither will offer good results. The decline in leverage shows the availability of cheaper sources of finance. Furthermore, it has been suggested that government interference in operational and administrative functions should be given the least priority.Правительство Индии в 1990-х гг. разработало универсальный метод влияния на эффективность деятельности государственных компаний путем дезинвестирования для улучшения их коммерческой составляющей и преодоления дефицита бюджета. Политика дезинвестирования направлена на сокращение доли государственного участия в экономике страны для стимулирования частного сектора. Цель исследования — эмпирическое изучение финансовых и операционных показателей тридцати двух ключевых предприятий государственного сектора (CPSE) Индии. Также авторы предлагают изучить другие факторы, влияющие на показатели эффективности компаний. В качестве методов статистического анализа данных использованы критерий знаковых рангов Уилкоксона (Wilcoxon signed-rank test) и модель регрессии панельных данных (random panel regression model). Результаты исследования демонстрируют, что дезинвестирование предприятий не приводит к значительному изменению показателей прибыльности. Производительность труда сотрудников, напротив, повышается. Отмечено положительное влияние на коэффициент выплаты дивидендов и численность сотрудников после пяти лет дезинвестирования, при этом эффект левериджа снижается незначительно. Кроме того, можно говорить об отрицательной корреляции между государственной собственностью и показателями эффективности. Это означает, что увеличение доли государственного участия будет негативно влиять на результаты деятельности компаний. С другой стороны, ВВП и размер предприятия положительно влияют на его прибыльность, а также производительность труда сотрудников. В работе сделан вывод о том, что государству необходимо сократить долю участия в государственном секторе, направив больше усилий на стратегическое (активное) дезинвестирование. Государству следует придерживаться идеи стратегического дезинвестирования, а не частичного, поскольку последнее не принесет высоких результатов. Снижение левериджа свидетельствует о доступности более дешевых источников финансирования. Также авторы предлагают свести к минимуму вмешательство государства в операционную и административную деятельность компаний

Upregulation of miR-23a∼27a∼24-2 Cluster Induces Caspase-Dependent and -Independent Apoptosis in Human Embryonic Kidney Cells

miRNAs have emerged as important players in the regulation of gene expression and their deregulation is a common feature in a variety of diseases, especially cancer. Currently, many efforts are focused on studying miRNA expression patterns, as well as miRNA target validation. Here, we show that the over expression of miR-23a∼27a∼24-2 cluster in HEK293T cells induces apoptosis by caspase-dependent as well as caspase-independent pathway as proved by the annexin assay, caspase activation, release of cytochrome-c and AIF (apoptosis inducing factor) from mitochondria. Furthermore, the over expressed cluster modulates the expression of a number of genes involved in apoptosis including FADD (Fas Associated protein with Death Domain). Bioinformatically, FADD is predicted to be the target of hsa-miR-27a and interestingly, FADD protein was found to be up regulated consistent with very less expression of hsa-miR-27a in HEK293T cells. This effect was direct, as hsa-miR-27a negatively regulated the expression of FADD 3′UTR based reporter construct. Moreover, we also showed that over expression of miR-23a∼27a∼24-2 sensitized HEK293T cells to TNF-α cytotoxicity. Taken together, our study demonstrates that enhanced TNF-α induced apoptosis in HEK293T cells by over expression of miR-23a∼27a∼24-2 cluster provides new insights in the development of novel therapeutics for cancer

Breakdown of Simple Scaling in Abelian Sandpile Models in One Dimension

We study the abelian sandpile model on decorated one dimensional chains. We determine the structure and the asymptotic form of distribution of avalanche-sizes in these models, and show that these differ qualitatively from the behavior on a simple linear chain. We find that the probability distribution of the total number of topplings $s$ on a finite system of size $L$ is not described by a simple finite size scaling form, but by a linear combination of two simple scaling forms $Prob_L(s) = 1/L f_1(s/L) + 1/L^2 f_2(s/L^2)$, for large $L$, where $f_1$ and $f_2$ are some scaling functions of one argument.Comment: 10 pages, revtex, figures include

Self-Organized States in Cellular Automata: Exact Solution

The spatial structure, fluctuations as well as all state probabilities of self-organized (steady) states of cellular automata can be found (almost) exactly and {\em explicitly} from their Markovian dynamics. The method is shown on an example of a natural sand pile model with a gradient threshold.Comment: 4 pages (REVTeX), incl. 2 figures (PostScript