Geodesic PCA in the Wasserstein space

We introduce the method of Geodesic Principal Component Analysis (GPCA) on the space of probability measures on the line, with finite second moment, endowed with the Wasserstein metric. We discuss the advantages of this approach, over a standard functional PCA of probability densities in the Hilbert space of square-integrable functions. We establish the consistency of the method by showing that the empirical GPCA converges to its population counterpart, as the sample size tends to infinity. A key property in the study of GPCA is the isometry between the Wasserstein space and a closed convex subset of the space of square-integrable functions, with respect to an appropriate measure. Therefore, we consider the general problem of PCA in a closed convex subset of a separable Hilbert space, which serves as basis for the analysis of GPCA and also has interest in its own right. We provide illustrative examples on simple statistical models, to show the benefits of this approach for data analysis. The method is also applied to a real dataset of population pyramids

Mastitis and its Effect on Chemical Composition of Milk in and around Worabe Town, Siltie Zone, Ethiopia

The study was undertaken from October, 2011 to June, 2012 to estimate prevalence of mastitis, to identify potential risk factors, and to assess impact of mastitis on chemical composition of cattle milk in and around Worabe town, Ethiopia. The study was conducted using California Mastitis Test for screening of subclinical mastitis, clinical examination and ultramilker to analyze chemical composition of milk. A total of 1,097 quarter milk samples collected from 290 local zebu and Holestein-zebu cross breed cows were examined; and overall prevalence of 46.9 and 24.3% was observed at cow and quarter level, respectively. Clinical and subclinical mastitis were detected with prevalence of 9.7 and 37.2%, respectively. From observed risk factors breed, milk yield, housing and feeding show statistically significance difference (p < 0.05) in prevalence of mastitis. Of all parameters, chemical composition of milk, statistically significant difference (P < 0.05) was observed in the mean fat composition among different mastitic milk. In conclusion, prevalent occurrence of mastitis accompanied with different potential risk factors was an important problem affecting dairy production; therefore, integrated control measures and monitoring were suggested

Child Malnutrition and Mortality in Developing Countries: Evidence from a Cross-Country Analysis

In this paper we propose and test an interpretative framework on the social and economic determinants of child malnutrition and child mortality, two key human development indicators. The paper is organized as follows. Section 1 illustrates the main economic and social factors causing child malnutrition and mortality. Section 2 identifies the main clusters of food insecure and vulnerable households and briefly describes their livelihood profiles. Section 3 exposes our cross-country estimation methodology. Section 4 reports and discusses the results. Section 5 concludes

COVID-19’s Impact on the Student Learning Process in Rwandan Higher Education Institutions

The coronavirus pandemic has not only challenged health systems, buthas also had a significant impact on education systems across the globe.This study analysed COVID-19’s impact on the student learning processin Higher Education Institutions in Rwanda. A quantitative research designwas adopted and pragmatism was selected as the research philosophy.Primary data was collected from 1 170 students in 30 institutions using aclosed-ended questionnaire. The data was analysed using descriptive andinferential statistical tools. The results indicate that the pandemic has led tochanges in the academic calendar, suspension of examinations, and final yearstudents being unable to conduct research and serve internships. Ithas also affected the quality of learning and learning from peers due tosocial distancing. Students in rural areas and those from vulnerable familieshave been worst affected. Key words: COVID-19, learning, higher education institutions, onlinelearning, student

Rapporto trimestrale: finanza pubblica e redistribuzione

Consiglio Nazionale delle Ricerche - Biblioteca Centrale - P.le Aldo Moro, 7, Rome / CNR - Consiglio Nazionale delle RichercheSIGLEITItal

Indigenous techniques for assessing and monitoring range resources in East Africa

Local knowledge, which refers to a social activity that has been set up primarily as a result of local initiative, or techniques that are endogenously generated, enforced and maintained has not been mainstreamed in rangeland development programmes in the region. This paradigm unfortunately overlooks the fact that local knowledge and experiences form the basis for local-level decision making in natural resource management. Recently there has been increasing interest and understanding of traditional knowledge systems in the fields of ethno-veterinary medicine but not so in natural resource management. Consequently, the ecological integrity of the rangelands is deteriorated because of increasing population growth, cultivation, overstocking, felling of trees, and other unsustainable resource utilization methods. In recognition of the role of traditional knowledge in natural resource management and sustainable development, case studies were conducted to document the traditional methods used to assess and monitor the condition and trend of grazing lands in East Africa by the Pokot and Il Chamus of Kenya, the Barabaig and Maasai of Tanzania, and the Bahima and Ateso of Uganda. The results of this study support the theory of the existence of complementary relationships between traditional techniques and modern scientific knowledge

Simple synthetic toll-like receptor 2 ligands

Dimeric/oligomeric states of G-protein coupled receptors have been difficult to target. We report here bivalent ligands consisting of two identical oxytocin-mimetics that induce a three order magnitude boost in G-protein signaling of oxytocin receptors (OTRs) in vitro and a 100- and 40-fold gain in potency in vivo in the social behavior of mice and zebrafish. Through receptor mutagenesis and interference experiments with synthetic peptides mimicking transmembrane helices (TMH), we show that such superpotent behavior follows from the binding of the bivalent ligands to dimeric receptors based on a TMH1-TMH2 interface. Moreover, in this arrangement, only the analogues with a well-defined spacer length (∼25 Å) precisely fit inside a channel-like passage between the two protomers of the dimer. The newly discovered oxytocin bivalent ligands represent a powerful tool for targeting dimeric OTR in neurodevelopmental and psychiatric disorders and, in general, provide a framework to untangle specific arrangements of G-protein coupled receptor dimers