On the Design of Education Conditional Cash Transfer Programs and non Education Outcomes: The Case of Teenage Pregnancy

We investigate the effect of education Conditional Cash Transfer programs (CCTs) on teenage pregnancy. Our main concern is with how the size and sign of the effect may depend on the design of the program. Using a simple model we show that an education CCT that conditions renewal on school performance reduces teenage pregnancy; the program can increase teenage pregnancy if it does not condition on school performance. Then, using an original data base, we estimate the causal impact on teenage pregnancy of two education CCTs implemented in Bogotá (Subsidio Educativo, SE, and Familias en Acción, FA); both programs differ particularly on whether school success is a condition for renewal or not. We show that SE has negative average effect on teenage pregnancy while FA has a null average effect. We also find that SE has either null or no effect for adolescents in all age and grade groups while FA has positive, null or negative effects for adolescents in different age and grade groups. Since SE conditions renewal on school success and FA does not, we can argue that the empirical results are consistent with the predictions of our model and that conditioning renewal of the subsidy on school success crucially determines the effect of the subsidy on teenage pregnancy.teenage risk taking behavior, teenage pregnancy, education, conditional cash transfers, incentives

On the design of education conditional cash transfer programs and non education outcomes: the case of teenage pregnancy

ABSTRACTWe investigate the effect of education Conditional Cash Transfer programs (CCTs) on teenage pregnancy. Our main concern is with how the size and sign of the effect may depend on the design of the program. Using a simple model we show that an education CCT that conditions renewal on school performance reduces teenage pregnancy; the program can increase teenage pregnancy if it does not condition on school performance. Then, using an original data base, we estimate the causal impact on teenage pregnancy of two education CCTs implemented in Bogotá (Subsidio Educativo, SE, and Familias en Acción, FA); both programs differ particularly on whether school success is acondition for renewal or not. We show that SE has negative average effect on teenage pregnancy while FA has a null average effect. We also Find that SE has either null or no effect for adolescents in all age and grade groups while FA has positive, null or negative effects for adolescents in different age and grade groups. Since SE conditions renewal on school success and FA does not, we can argue that the empirical results are consistent with the predictions of our model and that conditioning renewal of the subsidy on school success crucially determines the eect of the subsidy on teenage pregnancy.Teenage risk taking behavior, Teenage pregnancy, Education, Conditional Cash Transfers, Incentives.

Towards automatic Markov reliability modeling of computer architectures

The analysis and evaluation of reliability measures using time-varying Markov models is required for Processor-Memory-Switch (PMS) structures that have competing processes such as standby redundancy and repair, or renewal processes such as transient or intermittent faults. The task of generating these models is tedious and prone to human error due to the large number of states and transitions involved in any reasonable system. Therefore model formulation is a major analysis bottleneck, and model verification is a major validation problem. The general unfamiliarity of computer architects with Markov modeling techniques further increases the necessity of automating the model formulation. This paper presents an overview of the Automated Reliability Modeling (ARM) program, under development at NASA Langley Research Center. ARM will accept as input a description of the PMS interconnection graph, the behavior of the PMS components, the fault-tolerant strategies, and the operational requirements. The output of ARM will be the reliability of availability Markov model formulated for direct use by evaluation programs. The advantages of such an approach are (a) utility to a large class of users, not necessarily expert in reliability analysis, and (b) a lower probability of human error in the computation

Modelling of Mouse Spermatogonial Stem Cell Niche for Designing 3D scaffolds for in vitro Spermatogenesis

The homeostasis of male genitalia in mammals is maintained by a group of stem cells called spermatogonial stem cells (SSCs) which replenishes worn out cells in the testicular tissue. In mouse, these cells are housed by specialised tubular structures called seminiferous tubules. The SSC niche is found dispersed on the basal lamina, which is a two dimensional extracellular matrix along the circumference of seminiferous tubules. The Myoid, Sertoli and Leydig cells support SSCs while self-renewal and differentiation. The self-renewal and migration of SSCs takes place along the lateral direction and differentiation occurs medially towards the lumen of seminiferous tubules. The differentiation and self-renewal occurs in a cycle with each cycle possessing 12 stages of seminiferous epithelium. The self-renewal and commitment for differentiation of stem cells occurs from stages X – VIII of seminiferous epithelium. A MatlabTM program was developed to simulate the behavior of SSCs in their niche within the seminiferous tubules with logical rules. The migration, self-renewal and differentiation of SSCs was modelled according to the logical parameters provided by researches over the past century. The behavior of SSCs in their niche was assumed to be dependent on cell density in that niche area. The SSCs responded to the density stress imposed on them by their neighbouring cells which forced them migrate into a space with lower stress. Similarly, division and differentiation was also controlled by density stress through various thresholds. The model outcome was validated with literature. The model predicted that there was 12 Asingle cells, 15 Apaired cells and 19 Aaligned cells per 1000 Sertoli cells in the niche of mouse. With these metrics in concern, a biopolymer scaffold was prepared by using alginate to mimic the testicular tissue. Polymerisation was performed by the process of ionotropic gelation with CaCl2 as the crosslinker. Channels of diameter from 100 μm to 250 μmm were obtained in the anisotropic gel. The tubular nature of the scaffold mimicked seminiferous tubules in dimension. Physiochemical characterization like SEM, FTIR, Mechanical analysis of the scaffold was done on the scaffold

Crossover from Reptation to Rouse dynamics in the Extended Rubinstein-Duke Model

The competition between reptation and Rouse Dynamics is incorporated in the Rubinstein-Duke model for polymer motion by extending it with sideways motions, which cross barriers and create or annihilate hernias. Using the Density-Matrix Renormalization-Group Method as solver of the Master Equation, the renewal time and the diffusion coefficient are calculated as function of the length of the chain and the strength of the sideways motion. These new types of moves have a strong and delicate influence on the asymptotic behavior of long polymers. The effects are analyzed as function of the chain length in terms of effective exponents and crossover scaling functions.Comment: 16 Pages RevTeX and 13 PostScript figures included, accepted for publication in Phys. Rev.

Union Voices: Tactics and Tensions in UK Organizing

[Excerpt] This book tells the story of what is, in our view, probably the most significant development in British trade unionism of recent years: the increasing focus on organizing activity. We do this by reflecting on the impact of the UK\u27s Trades Union Congress (TUC) Organising Academy (OA), the participants in the training program, and the organizing campaigns that union organizers have run. We explicitly want to give voice to these union activists who have worked so hard to recruit and organize new union members. Much has already been written in the United Kingdom (often by us) about these developments but what is often lost in short articles or surveys are the stories that organizers have to tell. In an effort to build a base of knowledge from which to start to analyze changes, we have so far tended to focus on publishing the studies that demonstrate general trends and developments. This book seeks to do something slightly different. We draw on those previously published papers where necessary, but here we want to engage with the politics and tensions behind those trends; both on a macro and a micro level. We want to tell the stories of what organizing is like on the front line, what organizers do, and how they do it. The workplace struggles of workers and their unions are at the heart of these stories. But we also want to draw attention to the wider reasons why union organizing is important. As we will argue, one of the things that happened as ideas about organizing migrated from other countries— notably the United States and Australia—to the United Kingdom is that the political conceptualization of why unions are organizing has been underexamined. We want to understand and examine organizing as a political process, and we want to look at the politics within the union but also the wider purpose of organizing, which often varies from context to context

The typical cell in anisotropic tessellations

The typical cell is a key concept for stochastic-geometry based modeling in communication networks, as it provides a rigorous framework for describing properties of a serving zone associated with a component selected at random in a large network. We consider a setting where network components are located on a large street network. While earlier investigations were restricted to street systems without preferred directions, in this paper we derive the distribution of the typical cell in Manhattan-type systems characterized by a pattern of horizontal and vertical streets. We explain how the mathematical description can be turned into a simulation algorithm and provide numerical results uncovering novel effects when compared to classical isotropic networks.Comment: 7 pages, 7 figure