1,171 research outputs found

    Geochemistry of Ground Water - Surface Water Interactions and Metals Loading Rates in the North Fork of the American Fork River, Utah, from an Abandoned Silver/Lead Mine

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    The aqueous geochemistry and hydrology of the North Fork of the American Fork River, its tributaries, and the ground water in the vicinity of the Pacific Mine site were investigated in order to determine what impact ground water entering the North Fork has on toxic metal loads in the river. Toxic metal contamination in the North Fork is great enough that brown and cutthroat trout have absorbed lead, cadmium, and arsenic in their tissues at concentrations that are hazardous to human health if consumed. Ground water that flows through the mine site flows directly through the mine tailings before entering the North Fork, which produces an acidic ground water plume that has high concentrations of toxic metals. Together, the surface water discharge results and toxic metals concentrations from the surface and ground waters were used to determine toxic metals loading rates in the North Fork and its tributaries. The results suggest that the dissolved toxic metals (As, Cd, Cu, Fe, Mn, Pb, and Zn) enter the North Fork when the river is gaining water from the ground water. However, the total toxic metal load generally decreases through the reach of river adjacent to the mine site and is significantly greater than the dissolved load. Cadmium and Mn travel as dissolved species while Cu, Fe, Pb, and Zn travel as suspended solids in the North Fork and its tributaries. Arsenic seems to be associated with both the suspended solids and travel in the dissolved state. The geochemical modeling program PHREEQC and the diffuse double layer surface complexation model were used to investigate the chemistry that controls toxic metal mobility and attenuation in the surface and ground waters at the mine site. Based on PHREEQC results, the most important reaction in these waters is the precipitation of hydrous fe1Tic oxide. The toxic metals that sorb to the hydrous ferric oxide are Cu, Pb, most importantly Zn, and to a lesser degree As

    The effects of constructivism and behaviorism on the development of autonomy in young children

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    Autonomy, the ability to govern one\u27s self, is an admired attribute in adults. The concern for the development of autonomy in young children is not new to the field of education. Piaget acknowledged autonomy as the goal of education over 50 years ago (Piaget, 1932). It is the opinion of the followers of Piaget that in order to develop autonomy to a marked degree, children must be given opportunities to make decisions and gain control of their own lives. Piagetian theory maintains that children construct their own reality based on their interactions with their environment (Kamii & DeVries, 1978). Therefore, a teacher who is in agreement with the constructivist philosophy will create an atmosphere in which the children are encouraged to discover the laws of reality by testing their own hypotheses and making their own judgments

    Screening, Coulomb pseudopotential, and superconductivity in alkali-doped Fullerenes

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    We study the static screening in a Hubbard-like model using quantum Monte Carlo. We find that the random phase approximation is surprisingly accurate almost up to the Mott transition. We argue that in alkali-doped Fullerenes the Coulomb pseudopotential μ∗\mu^\ast is not very much reduced by retardation effects. Therefore efficient screening is important in reducing μ∗\mu^{\ast} sufficiently to allow for an electron-phonon driven superconductivity. In this way the Fullerides differ from the conventional picture, where retardation effects play a major role in reducing the electron-electron repulsion.Comment: 4 pages RevTeX with 2 eps figures, additional material available at http://www.mpi-stuttgart.mpg.de/docs/ANDERSEN/fullerene

    Similarities and differences in lipidomics profiles among healthy monozygotic twin pairs.

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    Differences in genetic background and/or environmental exposure among individuals are expected to give rise to differences in measurable characteristics, or phenotypes. Consequently, genetic resemblance and similarities in environment should manifest as similarities in phenotypes. The metabolome reflects many of the system properties, and is therefore an important part of the phenotype. Nevertheless, it has not yet been examined to what extent individuals sharing part of their genome and/or environment indeed have similar metabolomes. Here we present the results of hierarchical clustering of blood plasma lipid profile data obtained by liquid chromatographymass spectrometry from 23 healthy, 18-year-old twin pairs, of which 21 pairs were monozygotic, and 8 of their siblings. For 13 monozygotic twin pairs, within-pair similarities in relative concentrations of the detected lipids were indeed larger than the similarities with any other study participant. We demonstrate such high coclustering to be unexpected on basis of chance. The similarities between dizygotic twins and between nontwin siblings, as well as between nonfamilial participants, were less pronounced. In a number of twin pairs, within-pair dissimilarity of lipid profiles positively correlated with increased blood plasma concentrations of C-reactive protein in one twin. In conclusion, this study demonstrates that in healthy individuals, the individual genetic background contributes to the blood plasma lipid profile. Furthermore, lipid profiling may prove useful in monitoring health status, for example, in the context of personalized medicine. © 2008 Mary Ann Liebert, Inc. Chemicals / CAS: C-Reactive Protein, 9007-41-4; Lipid

    Homozygosity for a missense mutation in the 67 kDa isoform of glutamate decarboxylase in a family with autosomal recessive spastic cerebral palsy: parallels with Stiff-Person Syndrome and other movement disorders

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    Background Cerebral palsy (CP) is an heterogeneous group of neurological disorders of movement and/or posture, with an estimated incidence of 1 in 1000 live births. Non-progressive forms of symmetrical, spastic CP have been identified, which show a Mendelian autosomal recessive pattern of inheritance. We recently described the mapping of a recessive spastic CP locus to a 5 cM chromosomal region located at 2q24-31.1, in rare consanguineous families. Methods Here we present data that refine this locus to a 0.5 cM region, flanked by the microsatellite markers D2S2345 and D2S326. The minimal region contains the candidate gene GAD1, which encodes a glutamate decarboxylase isoform (GAD67), involved in conversion of the amino acid and excitatory neurotransmitter glutamate to the inhibitory neurotransmitter γ-aminobutyric acid (GABA). Results A novel amino acid mis-sense mutation in GAD67 was detected, which segregated with CP in affected individuals. Conclusions This result is interesting because auto-antibodies to GAD67 and the more widely studied GAD65 homologue encoded by the GAD2 gene, are described in patients with Stiff-Person Syndrome (SPS), epilepsy, cerebellar ataxia and Batten disease. Further investigation seems merited of the possibility that variation in the GAD1 sequence, potentially affecting glutamate/GABA ratios, may underlie this form of spastic CP, given the presence of anti-GAD antibodies in SPS and the recognised excitotoxicity of glutamate in various contexts

    Mitochondrial Substrate-Level Phosphorylation as Energy Source for Glioblastoma: Review and Hypothesis

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    Glioblastoma multiforme (GBM) is the most common and malignant of the primary adult brain cancers. Ultrastructural and biochemical evidence shows that GBM cells exhibit mitochondrial abnormalities incompatible with energy production through oxidative phosphorylation (OxPhos). Under such conditions, the mitochondrial F0-F1 ATP synthase operates in reverse at the expense of ATP hydrolysis to maintain a moderate membrane potential. Moreover, expression of the dimeric M2 isoform of pyruvate kinase in GBM results in diminished ATP output, precluding a significant ATP production from glycolysis. If ATP synthesis through both glycolysis and OxPhos was impeded, then where would GBM cells obtain high-energy phosphates for growth and invasion? Literature is reviewed suggesting that the succinate-CoA ligase reaction in the tricarboxylic acid cycle can substantiate sufficient ATP through mitochondrial substrate-level phosphorylation (mSLP) to maintain GBM growth when OxPhos is impaired. Production of high-energy phosphates would be supported by glutaminolysis-a hallmark of GBM metabolism-through the sequential conversion of glutamine -> glutamate -> alpha-ketoglutarate -> succinyl CoA -> succinate. Equally important, provision of ATP through mSLP would maintain the adenine nucleotide translocase in forward mode, thus preventing the reverse-operating F0-F1 ATP synthase from depleting cytosolic ATP reserves. Because glucose and glutamine are the primary fuels driving the rapid growth of GBM and most tumors for that matter, simultaneous restriction of these two substrates or inhibition of mSLP should diminish cancer viability, growth, and invasion

    Characterization and Whole Genome Analysis of Human Papillomavirus Type 16 E1-1374^63nt Variants

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    Background. The variation of the most common Human papillomavirus (HPV) type found in cervical cancer, the HPV16, has been extensively investigated in almost all viral genes. The E1 gene variation, however, has been rarely studied. The main objective of the present investigation was to analyze the variability of the E6 and E1 genes, focusing on the recently identified E1-1374^63nt variant. Methodology/Principal Findings. Variation within the E6 of 786 HPV16 positive cervical samples was analyzed using high-resolution melting, while the E1-1374^63nt duplication was assayed by PCR. Both techniques were supplemented with sequencing. The E1-1374^63nt duplication was linked with the E-G350 and the E-C109/G350 variants. In comparison to the referent HPV16, the E1-1374^63nt E-G350 variant was significantly associated with lower grade cervical lesions (p=0.029), while the E1-1374^63nt E-C109/G350 variant was equally distributed between high and low grade lesions. The E1-1374^63nt variants were phylogenetically closest to E-G350 variant lineage (A2 sub-lineage based on full genome classification). The major differences between E1-1374^63nt variants were within the LCR and the E6 region. On the other hand, changes within the E1 region were the major differences from the A2 sub-lineage, which has been historically but inconclusively associated with high grade cervical disease. Thus, the shared variations cannot explain the particular association of the E1-1374^63nt variant with lower grade cervical lesions. Conclusions/Significance. The E1 region has been thus far considered to be well conserved among all HPVs and therefore uninteresting for variability studies. However, this study shows that the variations within the E1 region could possibly affect cervical disease, since the E1-1374^63nt E-G350 variant is significantly associated with lower grade cervical lesions, in comparison to the A1 and A2 sub-lineage variants. Furthermore, it appears that the silent variation 109T>C of the E-C109/G350 variant might have a significant role in the viral life cycle and warrants further study

    Intimate Partner Violence and Abuse Against Men: Voices of Victimization Among Ex-Servicemen of the British Armed Forces

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    This study presents the personal testimonies of male British ex-Armed Forces personnel who have experienced violence and abuse victimization that was perpetrated by civilian female partners. In this research, we argue that to embark upon any understanding of the domestic lives of military personnel, an appreciation of the linkages to the cultural context of the military institution is necessary. Understanding the influence of the military institution beyond the military domain is crucial. We unveil the nature and character of the violence and abuse and how the servicemen negotiated their relationships. In doing so, we highlight the embodiment of military discipline, skills, and tactics in the home—not ones of violence which may be routinely linked to military masculinities; rather ones of restraint, tolerance, stoicism, and the reduction of a threat to inconsequential individual significance
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