The Value of Domestic Supply Chains: Producers,Wholesalers, and Urban Consumers in Colombia

Global value chains are potential links between smallholder farmers in developing countries and lucrative markets in industrialised nations. However, food access for poor consumers in Third World cities depends largely on traditional domestic supply chains. This article focuses on the market for perishables in Colombia, which is dominated by peasant farming and ranching, wholesale (spot) markets, and small, family‐run corner stores and butchers. Here, evidence suggests that, despite characterisation of traditional supply chains as inefficient, they provide critical outlets for smallholders' heterogeneous production while simultaneously ensuring availability of cheap food for poor urban consumers.     

Understanding Undocumented Migration from Honduras

Quantitative evidence on the drivers of undocumented migration from Honduras is limited. As a result, policy responses have been reactionary and understudied. Migration flows from the country are distinct from the rest of the region and merit study. By implementing different survey instruments, including focus groups, in‐depth interviews and a nationally representative survey, we build the first nationally representative data‐set on migrant attitudes in the country. Our results show that the propensity to migrate of individuals living in low‐income households is inversely related to human capital accumulation and access to basic services. Similarly, variables linked to networks in the destination country are positively correlated with the propensity to migrate. The prevalence of violence in areas where potential migrants live is unrelated to their migration decisions. This indicates that the focus of migration policy should rest in improving material conditions.     

Psychometric properties and criterion validity of the Perceived Vulnerability to Disease Scale (PVD) in the Spanish population / Propiedades psicométricas y validez de criterio de la escala de Percepción de Vulnerabilidad a la Enfermedad (PVE en población española)

Perceived Vulnerability to Disease may be defined as the beliefs about personal susceptibility to the transmission of infectious diseases and the emotional discomfort associated with the potential disease transmission. To evaluate these beliefs, the Perceived Vulnerability to Disease Scale (PVD) has been used in most studies. The aim of Study 1 was to validate the PVD questionnaire to the Spanish population. The sample was made up of 744 university students from all over Spain. Confirmatory factor analysis revealed that the items on the short version of the questionnaire corresponding to an interrelated two-factor model (perceived infectability and germ aversion) showed the best fit of all the tested models. In Study 2, scales to measure antifat attitudes, disgust and negative attitudes towards AIDS were used to analyse the criterion validity of the PVD questionnaire. The sample was made up of 434 university students. It was found that germ aversion was positively related with antifat attitudes, disgust and negative attitudes towards AIDS. In light of these results, we conclude that the short version of the questionnaire has good psychometric properties and can be used by the scientific community to measure Perceived Vulnerability to Disease.     

Classification Algorithm for Skin Color (CASCo): A new tool to measure skin color in social science research

Objective

A growing body of literature reveals that skin color has significant effects on people's income, health, education, and employment. However, the ways in which skin color has been measured in empirical research have been criticized for being inaccurate, if not subjective and biased.

Objective

Introduce an objective, automatic, accessible and customizable Classification Algorithm for Skin Color (CASCo).

Methods

We review the methods traditionally used to measure skin color (verbal scales, visual aids or color palettes, photo elicitation, spectrometers and image-based algorithms), noting their shortcomings. We highlight the need for a different tool to measure skin color

Results

We present CASCo, a (social researcher-friendly) Python library that uses face detection, skin segmentation and k-means clustering algorithms to determine the skin tone category of portraits.

Conclusion

After assessing the merits and shortcomings of all the methods available, we argue CASCo is well equipped to overcome most challenges and objections posed against its alternatives. While acknowledging its limitations, we contend that CASCo should complement researchers. toolkit in this area.     

Institutions and Development: A Conceptual Reanalysis

This essay reviews the concept of “institutions” as used in the recent economic literatures on firms and national development and notes its limitations. An alternative framework is proposed that draws on classic and contemporary sociological theory to position the concept of institutions in relation to other basic elements of culture and social structure. The framework is used to analyze (1) the failure of attempts to transplant institutions of developed countries into the global South and (2) the dynamics of massive privatization in Mexico. The bearing of this framework on current institutional theories of social change is examined, leading to the identification of sources of change at different levels of causal significance and scope. This modified theory of change is applied to the longstanding demographic debates on historical and institutional determinants of fertility transitions. The bearing of the proposed “thick institutionalist” framework on social theory and future development policies is discussed.     

The Erotic Lesbian in the Spanish Sexploitation Films of the 1970s

This article studies the representation of female homosexuality in the newly born erotic Spanish cinema of the 1970s, questioning the political and social implications of these first representations of lesbianism which contributed to shaping the first democratic discourses around women's sexuality. In order to do so, it looks at some of the most relevant films of the genre (most of which have never been studied before) and examines their portrayal of lesbian sex, focusing later on the figure of Ignacio F. Iquino and his film The Mask as the main representative of this genre in order to prove how the narrative construction of the eroticizing lesbian was largely based upon fascist conceptions of homosexuality.     

A geometrically motivated parametric model in manifold estimation

The general aim of manifold estimation is reconstructing, by statistical methods, an m-dimensional compact manifold S on ^d (with m≤d) or estimating some relevant quantities related to the geometric properties of S. Focussing on the cases d=2 and d=3, with m=d or m=d?1, we will assume that the data are given by the distances to S from points randomly chosen on a band surrounding S. The aim of this paper is to show that, if S belongs to a wide class of compact sets (which we call sets with polynomial volume), the proposed statistical model leads to a relatively simple parametric formulation. In this setup, standard methodologies (method of moments, maximum likelihood) can be used to estimate some interesting geometric parameters, including curvatures and Euler characteristic. We will particularly focus on the estimation of the (d?1)-dimensional boundary measure (in Minkowski's sense) of S. It turns out, however, that the estimation problem is not straightforward since the standard estimators show a remarkably pathological behaviour: while they are consistent and asymptotically normal, their expectations are infinite. The theoretical and practical consequences of this fact are discussed in some detail.     

Nonparametric estimation of the hazard function under dependence conditions

The estimation of the hazard rate has a great number of practical appli¬cations in dependence situations (seismicity analysis, reliability, economics), Based on kernel estimates of the density and the distribution function, we study the properties of the nonparametric estimator of the hazard function as-sociated with a strongly mixing time series. We prove consistency and asymp¬totic normality properties, and a cross-validation method for the smoothing parameter selection is studied. Some simulations and a practical application to real data are also shown.