128 research outputs found
Maternal iron deficiency perturbs embryonic cardiovascular development in mice.
Congenital heart disease (CHD) is the most common class of human birth defects, with a prevalence of 0.9% of births. However, two-thirds of cases have an unknown cause, and many of these are thought to be caused by in utero exposure to environmental teratogens. Here we identify a potential teratogen causing CHD in mice: maternal iron deficiency (ID). We show that maternal ID in mice causes severe cardiovascular defects in the offspring. These defects likely arise from increased retinoic acid signalling in ID embryos. The defects can be prevented by iron administration in early pregnancy. It has also been proposed that teratogen exposure may potentiate the effects of genetic predisposition to CHD through gene-environment interaction. Here we show that maternal ID increases the severity of heart and craniofacial defects in a mouse model of Down syndrome. It will be important to understand if the effects of maternal ID seen here in mice may have clinical implications for women
Chronic Wasting Disease Prions in Elk Antler Velvet
Residue 226 of cervid prion proteins may be a determinant of CWD pathogenesis
The Contribution of the Parietal Lobes to Speaking and Writing
The left parietal lobe has been proposed as a major language area. However, parietal cortical function is more usually considered in terms of the control of actions, contributing both to attention and cross-modal integration of external and reafferent sensory cues. We used positron emission tomography to study normal subjects while they overtly generated narratives, both spoken and written. The purpose was to identify the parietal contribution to the modality-specific sensorimotor control of communication, separate from amodal linguistic and memory processes involved in generating a narrative. The majority of left and right parietal activity was associated with the execution of writing under visual and somatosensory control irrespective of whether the output was a narrative or repetitive reproduction of a single grapheme. In contrast, action-related parietal activity during speech production was confined to primary somatosensory cortex. The only parietal area with a pattern of activity compatible with an amodal central role in communication was the ventral part of the left angular gyrus (AG). The results of this study indicate that the cognitive processing of language within the parietal lobe is confined to the AG and that the major contribution of parietal cortex to communication is in the sensorimotor control of writing
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Overview of Tabletop X-ray Laser Development at the Lawrence Livermore National Laboratory
It is almost a decade since the first tabletop x-ray laser experiments were implemented at the Lawrence Livermore National Laboratory (LLNL). The decision to pursue the picosecond-driven schemes at LLNL was largely based around the early demonstration of the tabletop Ne-like Ti x-ray laser at the Max Born Institute (MBI) as well as the established robustness of collisional excitation schemes. These picosecond x-ray lasers have been a strong growth area for x-ray laser research. Rapid progress in source development and characterization has achieved ultrahigh peak brightness rivaling the previous activities on the larger facilities. Various picosecond soft-x-ray based applications have benefited from the increased repetition rates. We will describe the activities at LLNL in this area
State Fragility, Rent Seeking and Lobbying: Evidence from African Data
This paper assesses the determinants of state fragility in sub-Saharan Africa using hitherto unexplored variables in the literature. The previously missing dimension of nation building is integrated and the hypothesis of state fragility being a function of rent seeking and/or lobbying by de facto power holders is tested. The resulting interesting finding is that, political interference, rent seeking and lobbying increase the probability of state fragility by mitigating the effectiveness of governance capacity. This relationship (after controlling for a range of economic, institutional and demographic factors) is consistent with a plethora of models and specifications. The validity of the hypothesis is confirmed in a scenario of extreme state fragility. Moreover, the interaction between political interferences and revolutions mitigate the probability of state fragility while the interaction between natural resources and political interferences breeds the probability of extreme state fragility. As a policy implication, there is a 'sub-Saharan African specificity' in 'nation building' and prevention of conflicts. Blanket fragility oriented policies will be misplaced unless they are contingent on the degree of fragility, since 'fragile' and 'extreme fragile' countries respond differently to economic, institutional and demographic characteristics of state fragility
Middle Class in Africa: Determinants and Consequences
This study complements the inclusive growth literature by examining the determinants and consequences of the middle class in a continent where economic growth has been relatively high. The empirical evidence is based on a sample of 33 African countries for a 2010 cross-sectional study. OLS, 2SLS, 3SLS and SUR estimation techniques are employed to regress a plethora of middle class indicators, notably, the: floating, middle-class with floating, middle-class without floating, lower-middle-income and upper-middle-income categories. Results can be classified into two main strands. First, results on determinants broadly show that GDP per capita and education positively affect all middle class dependent variables. However, we have seen a negative nexus for the effect of ethnic fragmentation, political stability in general and partially for economic vulnerability. Simple positive correlations have been observed for: the size of the informal sector, openness and democracy. Second, on the consequences, the middle class enables the accumulation of human and infrastructural capital, while its effect is null on political stability and democracy in the short-run but positive for governance and modernisation. Policy implications are discussed
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