Periodic Review, Push Inventory Policies for Remanufacturing

Sustainability has become a major issue in most economies, causing many leading companies to focus on product recovery and reverse logistics. This research is focused on product recovery, and in particular on production control and inventory management in the remanufacturing context. We study a remanufacturing facility that receives a stream of returned products according to a Poisson process. Demand is uncertain and also follows a Poisson process. The decision problems for the remanufacturing facility are when to release returned products to the remanufacturing line and how many new products to manufacture. We assume that remanufactured products are as good as new. In this paper, we employ a "push" policy that combines these two decisions. It is well known that the optimal policy parameters are difficult to find analytically; therefore, we develop several heuristics based on traditional inventory models. We also investigate the performance of the system as a function of return rates, backorder costs and manufacturing and remanufacturing lead times; and we develop approximate lower and upper bounds on the optimal solution. We illustrate and explain some counter-intuitive results and we test the performance of the heuristics on a set of sample problems. We find that the average error of the heuristics is quite low.inventory;reverse logistics;remanufacturing;environment;heuristics

Excitable Patterns in Active Nematics

We analyze a model of mutually-propelled filaments suspended in a two-dimensional solvent. The system undergoes a mean-field isotropic-nematic transition for large enough filament concentrations and the nematic order parameter is allowed to vary in space and time. We show that the interplay between non-uniform nematic order, activity and flow results in spatially modulated relaxation oscillations, similar to those seen in excitable media. In this regime the dynamics consists of nearly stationary periods separated by "bursts" of activity in which the system is elastically distorted and solvent is pumped throughout. At even higher activity the dynamics becomes chaotic.Comment: 4 pages, 4 figure

Evaluation of safety, efficacy, acceptance and expulsion of post placental intrauterine contraceptive device in a tertiary care centre

Background: Postpartum intrauterine device provides an effective temporary method of contraception for the woman who needs birth spacing rather than birth limitation and also a quasi-permanent family planning method. The aim of this study was to study the efficacy, acceptance, safety and complication of PPIUCD insertion.Method: This a retrospective analytical study done in a tertiary care teaching institute, Institute of Obstetrics and Gynaecology Egmore for a six-year period from January 2010 to December 2015 with a sample size of 81204. Outcomes measured were safety, efficacy, acceptance (patients and professionals) and complications.Results: For the study period of six years the total number of women delivered were 81204. A steady increase was noted in the insertion of PPIUCD from 2010 (1.98%) to 2015 (58%). 50.5% had insertion following caesarean section and 49.5% following vaginal delivery. Primipara had a higher rate of acceptance amounting to 74.74%. Most common complication reported was missing strings 9.25% and a greater part of the patients (83%) did not have any complaints.Conclusions: Enthusiasm and conviction on the part of the health care provider goes a long way in improving the acceptance rate of PPIUCD. It is an indispensable contraceptive tool for our country since our women most often do not return for postnatal contraceptive options

A Toy Model of Flying Snake's Glide

We have developed a toy model of flying snake's glide [J.J. Socha, Nature vol. 418 (2002) 603.] by modifying a model for a falling paper. We have found that asymmetric oscillation is a key about why snake can glide. Further investigation for snake's glide will provide us details about how it can glide without a wing.Comment: 6 pages, to be submitted to J. Phys. Soc. Jpn. Revised Version submitted to the abov

Periodic Review, Push Inventory Policies for Remanufacturing

Sustainability has become a major issue in most economies, causing many leading companies to focus on product recovery and reverse logistics. This research is focused on product recovery, and in particular on production control and inventory management in the remanufacturing context. We study a remanufacturing facility that receives a stream of returned products according to a Poisson process. Demand is uncertain and also follows a Poisson process. The decision problems for the remanufacturing facility are when to release returned products to the remanufacturing line and how many new products to manufacture. We assume that remanufactured products are as good as new. In this paper, we employ a "push" policy that combines these two decisions. It is well known that the optimal policy parameters are difficult to find analytically; therefore, we develop several heuristics based on traditional inventory models. We also investigate the performance of the system as a function of return rates, backorder costs and manufacturing and remanufacturing lead times; and we develop approximate lower and upper bounds on the optimal solution. We illustrate and explain some counter-intuitive results and we test the performance of the heuristics on a set of sample problems. We find that the average error of the heuristics is quite low

Evaluation of Clinical and Laboratory Parameters in patients with Hepatocellular Carcinoma.

INTRODUCTION : Hepatocellular carcinoma (HCC) is a major health problem responsible for fifth most common neoplasm in the world, and third most common cause of cancer related deaths. Age adjusted incidence is 5.5 – 14.9 per 100,000 population worldwide. Age adjusted incidence for HCC in developing countries are two to three fold higher than those in the developed countries. Almost 80% of liver cancers occur in developing countries like Asia and Africa. A rise in the incidence of mortality from HCC has been observed in different countries. Approximately 77% of deaths from HCC occur in developing countries. The prognosis of HCC is dismal with 5-year survival being 1–4%.3 Global distribution of HCC is very variable. Most Western countries have a low HCC incidence (<5 cases/ y/100,000), but most Asian countries have an intermediate (5–15 cases/y/1,000,000) or high (>15 cases/y/100,000) incidence of HCC. v Low incidence of <5 cases/y/100,000 of population has been reported from India.vi This low incidence is in contrast with the widespread contamination of foods with mycotoxins and the moderately high prevalence of hepatitis B virus (HBV) and hepatitis C virus (HCV) related chronic liver disease in India, which are considered as the most important risk factors for the development of HCC worldwide. In India, the mean incidence of HCC in four population-based registries is 2.77% for males and 1.38% for females. The prevalence of HCC in India varies from 0.2% to 1.6%. Hepatitis B virus infection is the most common etiologic factor in high incidence areas, while hepatitis C infection is more prevalent in the low incidence areas. Unlike other low incidence zone, in India HBV is the main etiological factor associated with HCC. In the west, majority of HCC are diagnosed incidentally during routine evaluation. However, in India, most of the patients in clinical practice present at an advanced stage ruling out curative treatment in most cases. Despite India being a low incidence zone for HCC, the estimated HCC cases in 2001 was 12 750.7 However, there is paucity of published literature on profile of HCC patients in India, making formulation of a proper health care strategy difficult. Most of the published literatures were retrospective studies and moreover limited number of studies available for South Indian population. Hence we have undertaken this study to analyze the characteristics of HCC, especially with regard to their clinical, etiological, radiological and cytohistological profile. AIMS & OBJECTIVE OF THE STUDY : The study was conducted with the objective of a) To study the clinical, etiological, radiological and cytohistological profile in patients with Hepatocellular carcinoma. b) To identify the association between serum alpha fetoprotein with stage of the disease. CONCLUSION : 1. The study includes total of seventy two patients, mean age was 54 years with male female ratio of 3:1. 2. Nearly half of the patients belong to the age group of 60 to 70 years. 3. Mean preadmission duration of illness was 54 days. 4. Twenty two percent of patients had cirrhosis and asymptomatic hepatocellular carcinoma (HCC) observed only in 2 cases. 5. Among the symptoms abdominal pain (66.7%) and weight loss (66.7%) were most commonly observed symptoms. 6. Hepatic decompensation was seen in half the patients at first presentation with ascites in 56.9%, jaundice in 22.2% and hepatic encephalopathy in 4.2% of patients. 7. Abdominal lump as a presentation observed in 12.5% of patients. 8. Hemorrhagic ascites noted in 11.1% of our cases. 9. The median serum AFP value of 515 ng/ml (range 1.3–92625) observed in the study population. Diagnostic value of AFP >400 ng/ml was present in only 61.5% cases with normal AFP in 14 of 70 (18.5%) patients. 10.More than three fourth of cases had esophageal varies with gastric varices of 8.3%. 11. HBV was the most common viral etiologic agent associated with HCC, observed in 23 of 52 (31.9%). Alcohol or HCV alone as an etiological agent was observed in 20.8% and 9.7% of cases respectively. 12. The average size of HCC was 6±4 cm (mean±SD). Very large tumors (>5 cm) were seen in two-third of cases. 13.CT appearance of HCC was hypo dense in 21.4%, mixed or heterogeneous density in 52.4% and hyper dense in 26.2% patients. 14.Vascular invasion of either major branch of splenoportal axis was seen in one fifth of the patients. 15. Diagnosis of HCC was made based on cytohistology in 31/36 (86.1%) patients. 16. More than three-fourth of HCC was in Okuda stage 2 (72.8%). Only five patients had Okuda stage 1 lesion. More than ninety percent of patient had CLIP score of ≥2. The serum AFP level was not associated with different stages of Okuda and CLIP Score (P >0.05, NS)

Evidence of a Sub-Saturn around EPIC~211945201

We report here strong evidence for a sub-Saturn around EPIC~211945201 and confirm its planetary nature. EPIC~211945201b was found to be a planetary candidate from {\it K2} photometry in Campaigns 5 \& 16, transiting a bright star ($V_{\rm mag}=10.15$, G0 spectral type) in a 19.492 day orbit. However, the photometric data combined with false positive probability calculations using VESPA was not sufficient to confirm the planetary scenario. Here we present high-resolution spectroscopic follow-up of the target using the PARAS spectrograph (19 radial velocity observations) over a time-baseline of 420 days. We conclusively rule out the possibility of an eclipsing binary system and confirm the 2-$\sigma$ detection of a sub-Saturn planet. The confirmed planet has a radius of 6.12$\pm0.1$$~R_{\oplus}$, and a mass of $27_{-12.6}^{+14}$~$M_{\oplus}$. We also place an upper limit on the mass (within the 3-$\sigma$ confidence interval) at 42~$M_{\oplus}$ above the nominal value. This results in the Saturn-like density of $0.65_{-0.30}^{+0.34}$ g~cm$^{-3}$. Based on the mass and radius, we provide a preliminary model-dependent estimate that the heavy element content is 60-70 \% of the total mass. This detection is important as it adds to a sparse catalog of confirmed exoplanets with masses between 10-70 $M_{\oplus}$ and radii between 4-8 $R_{\oplus}$, whose masses and radii are measured to a precision of 50\% or better (only 23 including this work).Comment: Accepted for publication in The Astronomical Journal, 17 pages, 8 figure

Scaling Laws for Advection Dominated Flows: Applications to Low Luminosity Galactic Nuclei

We present analytical scaling laws for self-similar advection dominated flows. The spectra from these systems range from 10$^{8}$ - 10$^{20}$ Hz, and are determined by considering cooling of electrons through synchrotron, bremsstrahlung, and Compton processes. We show that the spectra can be quite accurately reproduced without detailed numerical calculations, and that there is a strong testable correlation between the radio and X-ray fluxes from these systems. We describe how different regions of the spectrum scale with the mass of the accreting black hole, $M$, the accretion rate of the gas, $\dot{M}$, and the equilibrium temperature of the electrons, $T_e$. We show that the universal radio spectral index of 1/3 observed in most elliptical galaxies (Slee et al. 1994) is a natural consequence of self-absorbed synchrotron radiation from these flows. We also give expressions for the total luminosity of these flows, and the critical accretion rate, $\dot{M}_{crit}$, above which the advection solutions cease to exist. We find that for most cases of interest the equilibrium electron temperature is fairly insensitive to $M$, $\dot{M}$, and parameters in the model. We apply these results to low luminosity black holes in galactic nuclei. We show that the problem posed by Fabian & Canizares (1988) of whether bright elliptical galaxies host dead quasars is resolved, as pointed out recently by Fabian & Rees (1995), by considering advection-dominated flows.Comment: 30 pages, 5 postscript files. Accepted to ApJ. Also available http://cfa-www.harvard.edu/~rohan/publications.htm