Semiparametric Inference and Lower Bounds for Real Elliptically Symmetric Distributions

This paper has a twofold goal. The first aim is to provide a deeper understanding of the family of the Real Elliptically Symmetric (RES) distributions by investigating their intrinsic semiparametric nature. The second aim is to derive a semiparametric lower bound for the estimation of the parametric component of the model. The RES distributions represent a semiparametric model where the parametric part is given by the mean vector and by the scatter matrix while the non-parametric, infinite-dimensional, part is represented by the density generator. Since, in practical applications, we are often interested only in the estimation of the parametric component, the density generator can be considered as nuisance. The first part of the paper is dedicated to conveniently place the RES distributions in the framework of the semiparametric group models. The second part of the paper, building on the mathematical tools previously introduced, the Constrained Semiparametric Cram\'{e}r-Rao Bound (CSCRB) for the estimation of the mean vector and of the constrained scatter matrix of a RES distributed random vector is introduced. The CSCRB provides a lower bound on the Mean Squared Error (MSE) of any robust $M$-estimator of mean vector and scatter matrix when no a-priori information on the density generator is available. A closed form expression for the CSCRB is derived. Finally, in simulations, we assess the statistical efficiency of the Tyler's and Huber's scatter matrix $M$-estimators with respect to the CSCRB.Comment: This paper has been accepted for publication in IEEE Transactions on Signal Processin

A Motion Estimation based Algorithm for Encoding Time Reduction in HEVC

High Efficiency Video Coding (HEVC) is a video compression standard that offers 50% more efficiency at the expense of high encoding time contrasted with the H.264 Advanced Video Coding (AVC) standard. The encoding time must be reduced to satisfy the needs of real-time applications. This paper has proposed the Multi- Level Resolution Vertical Subsampling (MLRVS) algorithm to reduce the encoding time. The vertical subsampling minimizes the number of Sum of Absolute Difference (SAD) computations during the motion estimation process. The complexity reduction algorithm is also used for fast coding the coefficients of the quantised block using a flag decision. Two distinct search patterns are suggested: New Cross Diamond Diamond (NCDD) and New Cross Diamond Hexagonal (NCDH) search patterns, which reduce the time needed to locate the motion vectors. In this paper, the MLRVS algorithm with NCDD and MLRVS algorithm with NCDH search patterns are simulated separately and analyzed. The results show that the encoding time of the encoder is decreased by 55% with MLRVS algorithm using NCDD search pattern and 56% with MLRVS using NCDH search pattern compared to HM16.5 with Test Zone (TZ) search algorithm. These results are achieved with a slight increase in bit rate and negligible deterioration in output video quality

Microstructure evolution in AZ61 alloy processed by Equal Channel Angular Pressing

Abstract: Magnesium and its alloys have play an strategic role in many applications like aerospace, automobile, nuclear, electrical and structural engineering due to its strength to weight ratio is very low when compared to aluminum, Titanium and steel. In the present work, AZ61 wrought magnesium alloy was processed by using Equal Channel Angular Pressing (ECAP) at three different temperatures of 483 K, 523 K and 573 K using up to four ECAP passes. A microstructural study was conducted by measuring the average grain size after each pass, for the three different processing temperatures. The mechanical properties of the processed samples were noted to improve due to the reduction in the grain size after each ECAP pass. After four ECAP passes, the average grain size of the AZ61 samples was found to be reduced to 85%, 81%, and 70% for the pressing temperatures of 483 K, 523 K and 573 K respectively. The tensile strength of the AZ61 alloy increased with increase in number of ECAP passes for each of the temperatures when compared to as-received alloy. For instances, for the processing temperature of 483 K, 523 K and 573 K, the tensile strength increased to 24%, 10%, and 12% respectively at four ECAP pass. Also, the percentage elongation of the alloy was increased with increase in processing temperatures. Moreover, fracture topographies of the tensile surfaces are illustrated through scanning electron microcopy and reveal ductile fracture than as received alloy for four passes at each ECAP processing temperature

On the presence of sulphate in pituitary lutropin

The presence of sulphate in the carbohydrate of pituitary lutropin from different species has been investigated using a biosynthetic approach. Pituitaries from rats, rabbits, goats, and buffaloes were incubated in the presence of 35SO4- and the 35SO4--labelled proteins in the tissue immunoprecipitated with a well characterized anti-sheep lutropin serum. The incorporation into immunoreactive lutropin was low in the case of rat, rabbit and goat pituitaries while, it was considerable in the case of buffalo pituitaries. Hence further characterization studies were carried out on 35SO4--labelled proteins of buffaloes. The physico-chemical, immunological and biological properties of radio-labelled buffalo pituitary material were shown to be similar to those of standard lutropin. Inin vitro conditions of incubations, most of the incorporation of 35SO4- was observed into tissue lutropin while under similar conditions of incubation, [14C]-amino acids were found to get incorporated mostly into medium lutropin. The physiologically specific releasing hormone, lutropin-releasing hormone was found to stimulate the release of 35SO4--labelled lutropin from the rabbit pituitaries into the medium. These results give indirect evidence that sulphate could be present in pituitary lutropin

EFFECT OF LEAD ON MALE REPRODUCTION IN EXPERIMENTAL ANIMAL MODEL

Introduction: In early 1960\u27s, there is a first evidence of the toxic effects ionizing radiation on elevated oxygen levels in aerobes and proposed that oxygen toxicity is due to free radical formation. An alteration between oxidants and antioxidants in favour of the oxidants, potentially leading to damage is termed \u27oxidative stress\u27. Lead and cadmium do not have any detectable beneficial biological roles rather it produces detrimental effects on biochemical, physiological and behavioral dysfunctions. Even a little lead poisoning can cause serious health problems, and at very high levels, it can be fatal. Mainly it affects the heamopoeitc system, Liver, Kidney, Cardiovascular system and reproductive system. Methodology: Experimental rats, injected intraperitoneally with lead acetate for 15 days at the dosage of 50, 100 mg/kg/day body weight and compared to control rats injected with deionized distilled water instead. At the end of study testis were removed and right testis was used for testicular antioxidant Malandealdehyde (MDA) levels estimation by Thiobarbituric acid reactive substance assay and left testis was used for histopathological analysis. Unpaired t test and ANOVA was used for statistical analysis. Results : The MDA (nmole /gm tissue) levels in control, lead 50mg, lead 100mg groups were 12.16±0.4, 17.06±0.16 and 18.11±0.13. Histopathology examination Lumen showing decreased sperm count and maturation. Some of the lumens showing absence sperm maturation. Conclusion: Study on lead-exposed rat testis have shown that reduction of spermatogenesis formation and sperm maturation. Increased MDA levels indicate that it may be due to oxidative stress. The toxicity of lead was noted at level ≥50mg/kg. Key words: Lead; Lipid peroxidation; Male reproduction; Testicular histology

Anticonvulsant effect of nifedipine, dizepam and in combination on pentylenetetrazol induced experimental models of epilepsy on albino rats

Background: In many patients, the presently available antiepileptic drugs such as phenobarbital, phenytoin, benzodiazepines, sodium valproate, etc., are unable to control seizures efficiently and the problem of adverse effects has also not been circumvented completely and approximately 30% of the patients continue to have seizures with current antiepileptic drugs therapy. Hence, search should continue to develop newer, more effective, and safer neuro-protective agents for treatment of epilepsy. Aim of the study was to investigate the activity of nifedipine, the dihydropyridine calcium channel blocker, diazepam, the benzodiazepine anti- convulsant of established efficacy and their combinations against rat models of pentylenetetrazol (PTZ) induced convulsions. Method: Wister albino rats of either sex, weighing between 150-220gm were used. Rats were divided into 10 groups, in each group n=6 total N=60.Methods: PTZ was administration 30 min after test drug administration. Intraperitoneal injection of PTZ at the dose of 80mg/Kg body weight were administered to the rats to produce chemically-induced seizure. The effect of nifedipine and diazepam were assessed on such seizure model. The onset and duration of clonic convulsion were recorded.Results: The onset time of PTZ-induced clonic convulsion was significantly prolonged with the Nifedipine in the doses of 4mg and 8mg per Kg. in comparison to nifedipine in dose of 2mg per Kg. The interesting observation was that while Diazepam in 1mg/Kg. dose significantly (P<0.05) prolonged the onset time, there was significant decrease (P <0.001) in the onset time of PTZ-induced clonic convulsion with diazepam in doses of 2 and 4mg per Kg. in comparison to Diazepam 1mg per Kg. But the combination of diazepam 2.5 mg and Nifedipine 2.6mg and 5.3mg exhibited significant prolongation of the onset time. Diazepam 1 and 2mg per Kg was found to be equally effective in reduction of convulsion time, while 4mg dose showed more reduction of convulsion time. The combination of diazepam and nifedipine showed no better reduction in the convulsion time and also valproic acid in doses of 135mg. Kg.Conclusions: Nifedipine (3-5mg/Kg) and diazepam (2.5mg/Kg.) combination delayed the onset of convulsion. Diazepam 2mg / Kg. alone was effective in reduction of duration of convulsion. The combination dose having 2.6mg of nifedipine showed comparable protection with valproic acid 135mg per Kg. while the combination having 5.3mg of nifedipine showed significantly better protection. 

EFFECT OF LEAD ON MALE REPRODUCTION IN EXPERIMENTAL ANIMAL MODEL

Introduction: In early 1960's, there is a first evidence of the toxic effects ionizing radiation on elevated oxygen levels in aerobes and proposed that oxygen toxicity is due to free radical formation. An alteration between oxidants and antioxidants in favour of the oxidants, potentially leading to damage is termed 'oxidative stress'. Lead and cadmium do not have any detectable beneficial biological roles rather it produces detrimental effects on biochemical, physiological and behavioral dysfunctions. Even a little lead poisoning can cause serious health problems, and at very high levels, it can be fatal. Mainly it affects the heamopoeitc system, Liver, Kidney, Cardiovascular system and reproductive system. Methodology: Experimental rats, injected intraperitoneally with lead acetate for 15 days at the dosage of 50, 100 mg/kg/day body weight and compared to control rats injected with deionized distilled water instead. At the end of study testis were removed and right testis was used for testicular antioxidant Malandealdehyde (MDA) levels estimation by Thiobarbituric acid reactive substance assay and left testis was used for histopathological analysis. Unpaired t test and ANOVA was used for statistical analysis. Results : The MDA (nmole /gm tissue) levels in control, lead 50mg, lead 100mg groups were 12.16±0.4, 17.06±0.16 and 18.11±0.13. Histopathology examination Lumen showing decreased sperm count and maturation. Some of the lumens showing absence sperm maturation. Conclusion: Study on lead-exposed rat testis have shown that reduction of spermatogenesis formation and sperm maturation. Increased MDA levels indicate that it may be due to oxidative stress. The toxicity of lead was noted at level ≥50mg/kg. Key words:&nbsp;Lead; Lipid peroxidation; Male reproduction; Testicular histology

Cervical traction: a simple step ahead in the prevention of postpartum hemorrhage

Background: Postpartum hemorrhage is the most common preventable cause of maternal mortality in developing countries. The present study aimed to examine the impact of cervical traction technique in reducing the amount of postpartum blood loss and rate of PPH.Methods: This was a case-control, pilot study conducted in a tertiary hospital between June 2017 to June 2018. A total of 200 singletons, low-risk pregnant females, undergoing normal vaginal delivery, were enrolled in this study. Subjects showing a high risk for PPH were excluded. Patients were randomized as case group (n=100) and control group (n=100). The case group received sustained traction for 90 seconds to anterior and posterior lip of the cervix with active management of the third stage of labor, whereas the control group received routine active management of the third stage of labor. All subjects were followed up for 6 hours post-delivery. The amount of blood loss, hematocrit and hemoglobin post-delivery were compared between both groups.Results: The mean blood loss (ml), decrease in hemoglobin (g/L) and decrease in hematocrit post-delivery in cases were significantly low compared to controls (207±37.6 versus 340±49, P<0.01), (0.78±0.2 versus 1.4±0.3, P=0.03) and (1.7±0.2 versus 3.5±0.2, P<0.01). PPH occurred in 7 of 200 (3.5%) patients. The difference in the number of PPH was not significant (5/100; 5% versus 2/100; 2% P=0.2). There were no complications reported due to cervical traction.Conclusions: Cervical traction is a simple and safe maneuver to reduce the amount of postpartum blood loss. Larger RCT is recommended to investigate the reduction in PPH rate