MACROECONOMIC VARIABLES AND VOLUME OF TRANSACTIONS ON TEHRAN STOCK EXCHANGE

This paper examines the relationship between the volume of transactions and macroeconomic variables on the Tehran Stock Exchange. We are collect data for variables such as liquidity, inflation, exchange rate, the total value of imports and GDP for ten years period of 2009-2019. For analysis of data, have been used regression analytical method and ordinary least squares method (OLS) model. The results indicate that there are relationships between the macroeconomic variables of liquidity, inflation rate, and GDP with the volume of transactions. Therefore, the relationship between the volume of transactions with liquidity and GDP is positive and significant and with inflation is negative.

GM(1,1;λ) with Constrained Linear Least Squares

The only parameters of the original GM(1,1) that are generally estimated by the ordinary least squares method are the development coefficient a and the grey input b. However, the weight of the background value, denoted as λ, cannot be obtained simultaneously by such a method. This study, therefore, proposes two simple transformation formulations such that the unknown parameters, and can be simultaneously estimated by the least squares method. Therefore, such a grey model is termed the GM(1,1;λ). On the other hand, because the permission zone of the development coefficient is bounded, the parameter estimation of the GM(1,1) could be regarded as a bound-constrained least squares problem. Since constrained linear least squares problems generally can be solved by an iterative approach, this study applies the Matlab function lsqlin to solve such constrained problems. Numerical results show that the proposed GM(1,1;λ) performs better than the GM(1,1) in terms of its model fitting accuracy and its forecasting precision.

Predictores de salud y pobreza en contagios de covid-19 en municipios rurales

El objetivo fue analizar datos de salud y pobreza para encontrar causas de contagio de COVID-19 en municipios rurales segmentados por hombres y mujeres. Se elaboraron dos modelos de regresión lineal múltiple por el método de mínimos cuadrados ordinarios, con datos de municipios rurales del país. En los resultados se encontró que en los hombres el contagio aumenta cuando tienen neumonía, asma, hipertensión, obesidad y presentan alguna carencia social, en cambio, en las mujeres el contagio aumenta con neumonía, diabetes, inmunosupresión, obesidad, presencia de carencia social y vivir en pobreza extrema. Se recomienda dar continuidad al análisis de la pobreza en municipios rurales incluyendo la movilidad de la población para evitar contagios. El trabajo tiene como limitación la omisión de la edad, y su originalidad es el análisis de las causas de contagio de COVID-19 en las comunidades rurales. Se concluye que es necesario dar prioridad en atención de salud a los hombres con COVID-19 con enfermedades de asma, obesidad e hipertensión, así como a las mujeres con inmunosupresión y que viven en pobreza extrema. The objective was to analyze health and poverty data to find causes of contagion of COVID-19 in rural municipalities segmented by men and women. Two multiple linear regression models were developed using the ordinary least squares method, with data from rural municipalities in the country. In the results, it was found that in men the contagion increases when they have pneumonia, asthma, hypertension, obesity and present some social deprivation, on the other hand, in women the contagion increases with pneumonia, diabetes, immunosuppression, obesity, presence of social deprivation and live in extreme poverty. It is recommended to continue the analysis of poverty in rural municipalities including population mobility to avoid contagion. The work is limited by the omission of age, and its originality is the analysis of the causes of contagion of COVID-19 in rural communities. It is concluded that it is necessary to give priority in health care to men with COVID-19 with asthma, obesity and hypertension diseases, as well as to women with immunosuppression and living in extreme poverty.

Modeling the Future Value Distribution of a Life Insurance Portfolio

This paper addresses the problem of approximating the future value distribution of a large and heterogeneous life insurance portfolio which would play a relevant role, for instance, for solvency capital requirement valuations. Based on a metamodel, we first select a subset of representative policies in the portfolio. Then, by using Monte Carlo simulations, we obtain a rough estimate of the policies’ values at the chosen future date and finally we approximate the distribution of a single policy and of the entire portfolio by means of two different approaches, the ordinary least-squares method and a regression method based on the class of generalized beta distribution of the second kind. Extensive numerical experiments are provided to assess the performance of the proposed models.

Weather Trumps Festivity? More Cardiovascular Disease Events Occur in Winter than in December Holidays in Queensland, Australia

Objective: Cardiovascular disease (CVD) is the leading cause of hospitalisations and deaths in Australia. This study estimates the excess CVD hospitalisations and deaths across seasons and during the December holidays in Queensland, Australia. Methods: The study uses retrospective, longitudinal, population-based cohort data from Queensland, Australia from January 2010 to December 2015. The outcomes were hospitalisations and deaths categorised as CVD-related. CVD events were grouped according to when they occurred in the calendar year. Excess hospitalisations and deaths were estimated using the multivariate ordinary least squares method after adjusting for confounding effects. Results: More CVD hospitalisations and deaths occurred in winter than in summer, with 7811 (CI: 1353, 14,270; p < 0.01) excess hospitalisations and 774 (CI: 35, 1513; p < 0.01) deaths compared to summer. During the coldest month (July), there was an excess of 42 hospitalisations and 7 deaths per 1000 patients. Fewer CVD hospitalisations (−20 (CI: −29, −9; p < 0.01)) occurred during the December holidays than any other period during the calendar year. Non-CVD events were mostly not statistically significant different between periods. Conclusion: Most CVD events in Queensland occurred in winter rather than during the December holidays. Potentially cost-effective initiatives should be explored such as encouraging patients with CVD conditions to wear warmer clothes during cold temperatures and/or insulating the homes of CVD patients who cannot otherwise afford to.

The Impact of Money Demand Motivation on Money Supply Indonesia

This study aims to investigate the impact of money demand motive on a money supply based on keyness theory. The method used in this study is the ordinary least squares method with an annual period from 2011 to 2020. We find that In Indonesia, the money demand motive has a significant effect on money supply where the transaction motive has a significant negative relationship with the money supply. A precautionary motive has a significant positive correlation with the money supply. The motive of speculation has a significant positive relationship with the money supply.

Governance and the New Corona Virus (COVID-19) Outbreak in the World: Empirical Evidence

Aims: This paper aims to analyze the effect of public governance on the spread and mortality of the new corona virus. It focuses on the effects of differences observed in government’s responsiveness on the spread and mortality of this pandemic around the world. Sample: Our study is based on a sample of 129 countries from December, 8th 2019 to May 5th, 2020. Methods: The Ordinary Least Squares method is applied to cross-sectional data. We also proceed by descriptive statistics and scatter analyses to access the effect of public governance on the spread and the mortality of the Covid-19. Results: The results obtained show that government response time favors the speed of spread, level of infection, and mortality related to the Covid-19. The results indicate that countries in which governments have reacted early have lower levels of contamination and deaths than those that reacted late. Finally, our results suggest that the stringency of early government measures is a capital factor explaining the spread and mortality of this virus. Our results are robust to regional specificities, which distinguish relatively more resilient developing countries from developed countries with higher levels of contagion and mortality. Then, we recommend for all categories of countries a greater speed and rigour in government responsiveness in the management of pandemic diseases.

The effect of production costs on the provisioning management of materials: Evidence from paper industry in Peru

This paper presents an empirical investigation to evaluate the impact of purchase, storage and inventory management on the production costs of materials supply management in the Peruvian paper industry. A linear regression model was used under the ordinary least squares method to determine the causal relationship between the provisioning of materials and production costs. It was concluded that the evaluation of the effect between the study variables was inversely proportional, that is, as the management of purchase, storage, and inventory in companies improve, the production costs may also be reduced.

Geographical aggregation and incubator graduation performance: the role of incubator assistance

PurposeThis paper attempts to use agglomeration theory and ecological theory to explore how geographic agglomeration affects the graduation performance of incubator community. The authors argue that increasing the incubator community density can improve the opportunities for mutualism and learning among incubators. However, as the competition intensifies, the above positive relationship will weaken when the incubator density exceeds a certain level.Design/methodology/approachThe authors use a unique panel dataset of 438 National Technology Business Incubators (NTBIs) in China spanning from 2008 to 2012. Since each NTBIs contains multiple observations for different years, these observations that belong to a cross-section are not completely independent of each other; therefore, the regression using ordinary least squares method underestimates the standard deviations of the variables. To solve this problem, the authors regress this cluster panel data using the Newey–West robust variance estimator.FindingsThe empirical results show that incubator community density is conducive to promoting incubation performance, while the positive relationship between the incubator community density and incubation performance gradually weakens as the population density of incubators surpasses a certain level. Further, the authors examine how incubator assistance (technical assistance and business assistance) moderates the relationship between incubator density and incubation performance. The results indicate that this positive relationship is stronger when more business assistance is provided by incubator managers, while the moderating role of technical assistance is not supported.Originality/valueThis paper enriches the research on the relationship between incubator community density and graduation performance from the perspective of incubator assistance which helps start-ups to understand, absorb and transform external knowledge and resources, thereby promoting their growth.