252 research outputs found
sj-docx-1-mde-10.1177_23821205231168221 - Supplemental material for Attitudes and Perceived Barriers to Research Among Residents in Obstetrics and Gynecology in Trinidad and Tobago: A National Multicenter Cross-sectional Study
No full textSupplemental material, sj-docx-1-mde-10.1177_23821205231168221 for Attitudes and Perceived Barriers to Research Among Residents in Obstetrics and Gynecology in Trinidad and Tobago: A National Multicenter Cross-sectional Study by Sunil Persad, Saksham Mehra and Vanessa Harry in Journal of Medical Education and Curricular Development</p
Two Results on LPT: A Near-Linear Time Algorithm and Parcel Delivery Using Drones
No full textThe focus of this paper is to increase our understanding of the Longest Processing Time First (LPT) heuristic. LPT is a classical heuristic for the fundamental problem of uniform machine scheduling. For different machine speeds, LPT was first considered by Gonzalez et al. (SIAM J. Comput. 6(1):155–166, 1977). Since then, extensive work has been done to improve the approximation factor of the LPT heuristic. However, all known implementations of the LPT heuristic take O(mn) time, where m is the number of machines and n is the number of jobs. In this work, we come up with the first near-linear time implementation for LPT. Specifically, the running time is O((n+m)(log²m + log n)). Somewhat surprisingly, the result is obtained by mapping the problem to dynamic maintenance of lower envelope of lines, which has been well studied in the computational geometry community.
Our second contribution is to analyze the performance of LPT for the Drones Warehouse Problem (DWP), which is a natural generalization of the uniform machine scheduling problem motivated by drone-based parcel delivery from a warehouse. In this problem, a warehouse has multiple drones and wants to deliver parcels to several customers. Each drone picks a parcel from the warehouse, delivers it, and returns to the warehouse (where it can also get charged). The speeds and battery lives of the drones could be different, and due to the limited battery life, each drone has a bounded range in which it can deliver parcels. The goal is to assign parcels to the drones so that the time taken to deliver all the parcels is minimized. We prove that the natural approach of solving this problem via the LPT heuristic has an approximation factor of ϕ, where ϕ ≈ 1.62 is the golden ratio
Essays in Finance and Macroeconomics: Household Financial Obligations and the Equity Premium
No full textabstract: This dissertation is a collection of three essays relating household financial obligations to asset prices. Financial obligations include both debt payments and other financial commitments.
In the first essay, I investigate how household financial obligations affect the equity premium. I modify the standard Mehra-Prescott (1985) consumption-based asset pricing model to resolve the equity risk premium puzzle. I focus on two channels: the preference channel and the borrowing constraints channel. Under reasonable parameterizations, my model generates equity risk premiums similar in magnitudes to those observed in U.S. data. Furthermore, I show that relaxing the borrowing constraint shrinks the equity risk premium.
In the Second essay, I test the predictability of excess market returns using the household financial obligations ratio. I show that deviations in the household financial obligations ratio from its long-run mean is a better forecaster of future market returns than alternative prediction variables. The results remain significant using either quarterly or annual data and are robust to out-of-sample tests.
In the third essay, I investigate whether the risk associated with household financial obligations is an economy-wide risk with the potential to explain fluctuations in the cross-section of stock returns. The multifactor model I propose, is a modification of the capital asset pricing model that includes the financial obligations ratio as a ``conditioning down" variable. The key finding is that there is an aggregate hedging demand for securities that pay off in periods characterized by higher levels of financial obligations ratios. The consistent pricing of financial obligations risk with a negative risk premium suggests that the financial obligations ratio acts as a state variable.Dissertation/ThesisDoctoral Dissertation Economics 201
Assessment of Radiological and Chemical Risk due to Natural Radionuclides and Heavy Metals in Water, Soil and Food
No full textWith the growing global concern regarding environmental pollution, it is essential
to comprehend its effects with timely monitoring. The objective of this study is to
measure the concentrations of natural radionuclides such as 238 U, 232 Th and 40 K in
addition to heavy metals in the water and food to analyze the potential health risks
to the population of Mansa district, located within the cancer belt of Punjab which
is distinguished for its association with cotton cultivation, earning it the moniker
’area of white gold’. The fertiliser usage is high in the study area. The study utilizes
comprehensive assessment techniques that encompasses probabilistic approach as
well as deterministic approach for water contamination to evaluate the corresponding
health risks. Moreover, biokinetic modelling of uranium resulting from ingestion of
uranium contaminated water is performed to assess the retention of uranium in the
human body. The natural radiolonuclides are measured for both soil and food. The
heavy metals analysis is also carried out for wheat samples. The research findings
indicate a high level of uranium and cadmium contamination of groundwater in
Mansa district, Punjab (India), raising concerns regarding safety of its utilisation for
domestic purposes. Although the wheat samples have cadmium concentration above
permissible limits set by Kent but the values are below Indian permissible limits.
The activity of natural radionuclides 226 Ra, 232 Th and 40 K in soil samples are within
permissible limits whereas the activity of 40 K in wheat samples is above permissible
limit. This thesis offers significant insights into the health challenges encountered by
the population of Mansa due to regular use of groundwater. By identifying key areas
of concern, the study seeks to bolster initiatives aimed at enhancing environmental
and health safety for the population
A Time-Varying Premium for Idiosyncratic Risk: Its Effects on the Cross-Section of Stock Returns
No full textabstract: Merton (1987) predicts that idiosyncratic risk can be priced. I develop a simple equilibrium model of capital markets with information costs in which the idiosyncratic risk premium depends on the average level of idiosyncratic volatility. This dependence suggests that the idiosyncratic risk premium varies over time. I find that in U.S. markets, the covariance between stock-level idiosyncratic volatility and the idiosyncratic risk premium explains future stock returns. Stocks in the highest quintile of the covariance between the volatility and risk premium earn an average 3-factor alpha of 70 bps per month higher than those in the lowest quintile.Dissertation/ThesisDoctoral Dissertation Business Administration 201
A systematic review of the determinants and the behaviour of equity risk premium
No full textUnderstanding the Equity Risk Premium (ERP) and the factors affecting it is cardinal to financial economics, particularly to equity research analysts, domestic and international institutional investors and financial economist. Since the seminal work of Mehra and Prescott (1985) there has been an exponential rise in the research explaining the reasons for ERP puzzle. This review, systematically, investigates the literature related to ERP in four key dimensions. The first dimension is regarding the issues related to different techniques of estimating the ERP. The second dimension is regarding the studies that explain the reasons of existence of the ERP puzzle by making modifications to the preference structures. The third is regarding the macroeconomic variables that help in predicting ERP and the fourth deals with studies that are conducted in the international context. In addition to this, this review meticulously captures some important limitations of the existing literature regarding the estimation of ERP and identifies the domestic and international determinants of ERP, in particular the UK ERP and proposes novel future directions of research. These future research directions have two important implications for my PhD. The first is the academic contribution that predominantly comes from methodological contribution of estimating the ERP. The second is the practical contribution that comes mainly from identifying the unique set of variables (UK domestic and international), which are of prime importance to the domestic and foreign institutional investors because of the financial crisis of 2008-2009 and which should affect the UK ERP
The Romanticization of Mental Illness and Substance Abuse in Young Adult Media
No full textabstract: The following creative project defends that, whether intentionally or not, mental illness and substance abuse are inevitably romanticized in young adult media and discusses the dangers of this romanticization. This project is divided into three parts. The first part consists of psychological evaluations of the main characters of two popular, contemporary forms of young adult media, Catcher in the Rye by J.D Salinger and Euphoria by Sam Levinson. These evaluations use textual evidence and the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) to determine what symptoms of psychopathology the characters appear to display. The second part consists of a self-written short story that is meant to accurately depict the life of a young adult struggling with mental illness and substance abuse. This story contains various aesthetic techniques borrowed from the two young adult media forms. The final part consists of an aesthetic statement which discusses in depth the aesthetic techniques employed within the short story, Quicksand by Anisha Mehra. (abstract
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