Measuring Racial Segregation in Los Angeles County using Random Walks

As of now there is no universal quantitative measure used to evaluate racial segregation in different regions. This paper begins by providing a history of segregation, with an emphasis on the impact of redlining in the early 20th century. We move to its effect on the current population distribution in Los Angeles, California, and then provide an overview of the mathematical concepts that have been used in previous measurements of segregation. We then introduce a method that we believe encompasses the most representative aspects of preceding work, proposed by Sousa and Nicosia in their work on quantifying ethnic segregation in cities using random walks: Given a graph with racial population information at each node, this method conducts a random walk and outputs the number of steps it takes to reach all racial groups in the system. In analyzing the amount of time the walk takes, we are able to form conclusions about the levels of segregation present in the region. We argue that this measure is more effective than those used previously because of its high explanatory power and preservation of graph structure. We applied this method to LA County with data collected from the U.S. 2020 Census, and found that there is a significant difference between the average step length of LA County vs. the average step length of an unbiased null model. The impacts of this study imply that LA County is racially segregated in comparison to a given neutral null model

Pengaruh Profitabilitas, Likuiditas dan Leverage Terhadap Kebijakan Dividen Pada Sektor Infrastruktur

Dividend policy is a decision regarding the distribution of profits earned by the company, whether to be distributed to shareholders or to be retained in the form of retained earnings to finance investments in the future. This study aims to examine the effect of profitability, liquidity and leverage on dividend policy in infrastructure sector companies. Samples were taken as many as 14 companies. The method of determining the sample used in this research is purosive sampling. Data were analyzed using SPSS. The results showed that profitability had a significant positive effect on dividend policy. liquidity has no effect on dividend policy. leverage has no effect on dividend policy. This research suggests providing knowledge or education related to dividend policy.Kebijakan dividen merupakan keputusan mengenai pembagian keuntungan yang diperoleh perusahaan, apakah akan dibagikan kepada pemegang saham atau ditahan dalam bentuk laba ditahan untuk membiayai investasi di masa yang akan datang. Penelitian ini bertujuan untuk menguji pengaruh profitabilitas, likuiditas dan leverage terhadap kebijakan dividen pada perusahaan sektor infrastruktur. Sampel yang diambil sebanyak 14 perusahaan. Metode penentuan sampel yang digunakan dalam penelitian ini adalah purosive sampling. Data dianalisis menggunakan SPSS. Hasil penelitian menunjukkan bahwa profitabilitas berpengaruh positif signifikan terhadap kebijakan dividen. likuiditas tidak berpengaruh terhadap kebijakan dividen. leverage tidak berpengaruh terhadap kebijakan dividen. Penelitian ini menyarankan untuk memberikan pengetahuan atau edukasi terkait kebijakan dividen

Benign Pneumoperitoneum after Colonoscopy

Pneumoperitoneum frequently indicates a perforated abdominal viscus that requires emergent surgical management. However; pneumoperitoneum, on rare occasion, can occur without perforation. In these cases, it is defined as benign pneumoperitoneum. Benign pneumoperitoneum means asymptomatic free intra-abdominal air or pneumoperitoneum without peritonitis and can occur occasionally with colonoscopy. In this paper, we present a rare case of benign pneumoperitoneum that developed after diagnostic colonoscopy and review it in conjunction with the current literature

The Influence Of Managerial Ownership Structure, Asset Structure, Liquidity, Business Risk, Dividend Policy, Firm Size, And Profitability On The Capital Structure In The Firms Of Hotel, Restaurant, And Tourism Industry

The determination of capital structure policy becomes important in the hotels, restaurants and tourism industry in Indonesia. This industry environment has a fairly high business fluctuations because the product that being offered is a product that requires a large capital. The firms in this industry which in have capital intensive, but also have a quite high business risks. On the other hand, firms also need to take care of the capital structure that will be used. It is the goal of this studies so that it can be the information for the firm to determine the optimal capital structure. The results of this study are simultaneously factors managerial ownership structure, asset structure, liquidity, business risk, dividend policy, the size and profitability of the firm has no significant effect on the capital structure of the firm, while only partially profitability factor that showed a significant negative effect on capital structure. This means there is a tendency of firms in this industry in Indonesia to use funding from internal sources to finance its business expansio

Mathematical Modelling of Glioblastomas Invasion within the Brain:A 3D Multi-Scale Moving-Boundary Approach

International audienceBrain-related experiments are limited by nature, and so biological insights are often limited or absent. This is particularly problematic in the context of brain cancers, which have very poor survival rates. To generate and test new biological hypotheses, researchers have started using mathematical models that can simulate tumour evolution. However, most of these models focus on single-scale 2D cell dynamics, and cannot capture the complex multi-scale tumour invasion patterns in 3D brains. A particular role in these invasion patterns is likely played by the distribution of micro-fibres. To investigate the explicit role of brain micro-fibres in 3D invading tumours, in this study, we extended a previously introduced 2D multi-scale moving-boundary framework to take into account 3D multi-scale tumour dynamics. T1 weighted and DTI scans are used as initial conditions for our model, and to parametrise the diffusion tensor. Numerical results show that including an anisotropic diffusion term may lead in some cases (for specific micro-fibre distributions) to significant changes in tumour morphology, while in other cases, it has no effect. This may be caused by the underlying brain structure and its microscopic fibre representation, which seems to influence cancer-invasion patterns through the underlying cell-adhesion process that overshadows the diffusion process

A New Approach for Solving Inverse Scattering Problems with Overset Grid Generation Method

This paper presents a new approach of Forward-Backward Time-Stepping (FBTS) utilizing Finite-Difference Time-Domain (FDTD) method with Overset Grid Generation (OGG) method to solve the inverse scattering problems for electromagnetic (EM) waves. The proposed FDTD method is combined with OGG method to reduce the geometrically complex problem to a simple set of grids. The grids can be modified easily without the need to regenerate the grid system, thus, it provide an efficient approach to integrate with the FBTS technique. Here, the characteristics of the EM waves are analyzed. For the research mentioned in this paper, the ‘measured’ signals are syntactic data generated by FDTD simulations. While the ‘simulated’ signals are the calculated data. The accuracy of the proposed approach is validated. Good agreements are obtained between simulation data and measured data. The proposed approach has the potential to provide useful quantitative information of the unknown object particularly for shape reconstruction, object detection and others