964 research outputs found
Allergy, soil-transmitted helminths and their association: Epidemiological studies in Cuban schoolchildren
Get PDFTwisk, J.W.R. [Promotor]Polman, C.B. [Copromotor]Campos Ponce, M. [Copromotor]Bonet, M. [Copromotor
Helminth infections and micronutrients in children
Get PDFEck Van Der Sluijs - Van De Bor, M. [Promotor]Polman, C.B. [Copromotor]Campos Ponce, M. [Copromotor]Wieringa, F.T. [Copromotor
Measuring Vulnerability to Poverty Using Long-Term Panel Data
No full textMeasuring Vulnerability to Poverty Using Long-Term Panel Data Author & abstract Download & other version 16 References 4 Citations Related works & more Corrections Author Listed: Katja Landau (Georg-August-University Göttingen) Stephan Klasen (Georg-August-University Göttingen) Walter Zucchini (Georg-August-University Göttingen) Registered: Stephan Klasen Abstract We investigate the accuracy of ex ante assessments of vulnerability to income poverty using cross-sectional data and panel data. We use long-term panel data from Germany and apply di fferent regression models, based on household covariates and previous-year equivalence income, to classify a household as vulnerable or not. Predictive performance is assessed using the Receiver Operating Characteristics (ROC), which takes account of false positive as well as true positive rates. Estimates based on cross-sectional data are much less accurate than those based on panel data, but for Germany, the accuracy of vulnerability predictions is limited even when panel data are used. In part this low accuracy is due to low poverty incidence and high mobility in and out of poverty
Resilience as a positive lever: An analysis of sensemaking and meaningful work in the context of organizational change
No full textAuthor Katja SchwarzMasterarbeit Johannes Kepler Universität Linz 2024Arbeit nach Ablauf der Sperre auf den öffentlichen PCs in den Bibliotheken der JKU+Medizin abrufba
Measuring Vulnerability to Poverty Using Long-Term Panel Data
No full textMeasuring Vulnerability to Poverty Using Long-Term Panel Data Author & abstract Download & other version 16 References 4 Citations Related works & more Corrections Author Listed: Katja Landau (Georg-August-University Göttingen) Stephan Klasen (Georg-August-University Göttingen) Walter Zucchini (Georg-August-University Göttingen) Registered: Stephan Klasen Abstract We investigate the accuracy of ex ante assessments of vulnerability to income poverty using cross-sectional data and panel data. We use long-term panel data from Germany and apply di fferent regression models, based on household covariates and previous-year equivalence income, to classify a household as vulnerable or not. Predictive performance is assessed using the Receiver Operating Characteristics (ROC), which takes account of false positive as well as true positive rates. Estimates based on cross-sectional data are much less accurate than those based on panel data, but for Germany, the accuracy of vulnerability predictions is limited even when panel data are used. In part this low accuracy is due to low poverty incidence and high mobility in and out of poverty
Resilience as a positive lever: An analysis of sensemaking and meaningful work in the context of organizational change
No full textAuthor Katja SchwarzMasterarbeit Johannes Kepler Universität Linz 2024Arbeit nach Ablauf der Sperre auf den öffentlichen PCs in den Bibliotheken der JKU+Medizin abrufba
Antimalarial artesunate-mefloquine versus praziquantel in African children with schistosomiasis: an open-label, randomized controlled trial
No full text"Meghillàt Estèr". Toward a Transcultural Concept of Religion in Katja Petrowskaja\u27s Novel Vielleicht Esther
No full textIl presente contributo intende rileggere il romanzo Vielleicht Esther (2014) di Katja Petrowskaja proponendo come chiave di lettura la Meghillàt Estèr della Bibbia ebraica. Si vuole dimostrare come, attraverso questo implicito ma preciso riferimento intertestuale, l’autrice affronti nel romanzo anche una riflessione su una possibile transreligione capace di rispecchiare il contesto transculturale contemporaneo.This contribution analyzes Katja Petrowskaja’s novel Vielleicht Esther (2014) by proposing the Megillàt Estèr from the Hebrew Bible as a key interpretative lens. The aim is to demonstrate how, through this subtle yet deliberate intertextual reference, the author weaves into the novel a reflection on the notion of a transreligion, one that resonates with and articulates the complexities of our contemporary transcultural landscape
Casanovas are liars : behavioral syndromes, sperm competition risk, and the evolution of deceptive male mating behavior in live-bearing fishes [version 2; referees: 2 approved, 1 approved with reservations]
No full textMale reproductive biology can by characterized through competition over mates as well as mate choice. Multiple mating and male mate choice copying, especially in internally fertilizing species, set the stage for increased sperm competition, i.e., sperm of two or more males can compete for fertilization of the female’s ova. In the internally fertilizing fish Poecilia mexicana, males respond to the presence of rivals with reduced expression of mating preferences (audience effect), thereby lowering the risk of by-standing rivals copying their mate choice. Also, males interact initially more with a non-preferred female when observed by a rival, which has been interpreted in previous studies as a strategy to mislead rivals, again reducing sperm competition risk (SCR). Nevertheless, species might differ consistently in their expression of aggressive and reproductive behaviors, possibly due to varying levels of SCR. In the current study, we present a unique data set comprising ten poeciliid species (in two cases including multiple populations) and ask whether species can be characterized through consistent differences in the expression of aggression, sexual activity and changes in mate choice under increased SCR. We found consistent species-specific differences in aggressive behavior, sexual activity as well as in the level of misleading behavior, while decreased preference expression under increased SCR was a general feature of all but one species examined. Furthermore, mean sexual activity correlated positively with the occurrence of potentially misleading behavior. An alternative explanation for audience effects would be that males attempt to avoid aggressive encounters, which would predict stronger audience effects in more aggressive species. We demonstrate a positive correlation between mean aggressiveness and sexual activity (suggesting a hormonal link as a mechanistic explanation), but did not detect a correlation between aggressiveness and audience effects. Suites of correlated behavioral tendencies are termed behavioral syndromes, and our present study provides correlational evidence for the evolutionary significance of SCR in shaping a behavioral syndrome at the species level across poeciliid taxa
Evolutionair potentieel van de humane parasiet Schistosoma mansoni in een veranderende wereld
No full textThe human helminth parasite Schistosoma spp. lives in the blood vessels of over 200 million people in Africa, Asia and South-America. The most serious infections are found in children and adolescents who eventually become physically and intellectually compromised, while people who have been infected chronically may develop liver damage, kidney failure or bladder cancer. Despite the availability of a cheap and effective drug, the disease has been largely neglected compared to other more deadly diseases such as HIV/AIDS and malaria, both in terms of disease control and in terms of scientific research. Remedial action is therefore needed to gain insight into the distribution of these parasites at both a local (among humans and villages) and a global geographic scale (across regions or continents). It is essential to understand the factors and dynamics that shape transmission and the impact of selective pressures such as drug treatment. This will provide a theoretical framework that could represent a starting point for better disease control.In this thesis we performed a population genetic study to reveal the distribution of Schistosoma mansoni parasites in the basin of the Senegal River (West Africa). Molecular markers such as microsatellites or single nucleotide polymorphisms serve as ideal tools to track the transmission of parasites and infer their ancestry. However, parasite worms cannot be used as a source for DNA as they are inaccessible within the human blood vessels. A protocol was therefore optimized that allowed the sampling, DNA-extraction and molecular analysis based on low quantities of DNA obtained from individual larval parasites (chapter 2). This optimization was an important first step that enabled us to perform multiple analyses on the same individual parasite with low genotyping error rates.The case study in Northwest Senegal represents one of the most intense epidemic foci of S. mansoni. The parasite invaded this area in 1986 after the construction of two dams on the Senegal River. Parasites were obtained at four time points over a period of 14 years (1993-2007) and from several regions (Northwest Senegal, Southeast Senegal and Mali) to study the nature of the S. mansoni epidemic (chapter 3). Typing of nuclear and mitochondrial markers revealed that parasites from Northwest Senegal have a West-African origin, that they harbor moderate to high levels of genetic diversity, that they increase in population size and that some parasites are genetically different from others (chapter 3). These results suggest that the epidemic of schistosomiasis in Northwest Senegal was probably not elicited by a few S. mansoni parasites, but that the colonization history is much more complex. It is most likely that a multitude of parasites successfully colonized the local human population. Furthermore, most of the parasite genetic variation observed in the region was found within individual human hosts (chapter 4), suggesting that they accumulate a wide range of parasites during their lifetime. However, children appeared to be much more infected by related parasites than adult hosts, who tended to be infected by more genetically diverse parasites. The age-dependent recruitment of genetically diverse parasite infections may be explained by (1) genotype-dependent concomitant immunity that leads to selective recruitment of genetically unrelated worms with host age, and/or (2) the genetic mixing bowl hypothesis, where older hosts have been exposed to a wider variety of parasites than children.Currently the cheap and effective drug praziquantel is used to treat schistosomiasis. However, this could lead to serious bottlenecks in S. mansoni populations, possibly leading to increased inbreeding, low levels of genetic diversity and the random fixation of (possibly deleterious) alleles. The effect of treatment on the genetic composition of S. mansoni populations was therefore studied using data obtained from simulations of an island model at equilibrium (chapter 5) and from naturally collected parasites before and after treatment (chapter 6). Both studies showed that treatment has only a limited effect on the genetic diversity of schistosome populations. Complementary simulations revealed that only a sustained treatment policy could decrease schistosome population sizes and therefore drive the success of a control program.This thesis has shed new light on the factors that shape the distribution of S. mansoni parasites. The main conclusion is that S. mansoni populations harbor substantial levels of genetic diversity, and hence are able to cope with strong selection pressures such as chemotherapeutic treatment. This large evolutionary potential will hamper attempts either to control or to eliminate these parasites, as well as complicate the development of new drugs or vaccines.status: Publishe
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