1,127 research outputs found
Relation of carbon dioxide in flue gases to the efficiency of a boiler
This thesis was undertaken to demonstrate the practical utility of measuring the efficiency of a Heine Boiler, installed in the Power Plant at the Missouri School of Mines, by the amount of CO₂ in the flue gases. The tests were made on a new boiler which had recently been installed in the Power Plant. The boiler and setting being new, the tests should show a high percentage of CO₂ in the flue gases and a high evaporative efficiency by the boiler --page 3
A major QTL corresponding to the Rk locus for resistance to root-knot nematodes in cowpea (Vigna unguiculata L. Walp.).
Key messageGenome resolution of a major QTL associated with the Rk locus in cowpea for resistance to root-knot nematodes has significance for plant breeding programs and R gene characterization. Cowpea (Vigna unguiculata L. Walp.) is a susceptible host of root-knot nematodes (Meloidogyne spp.) (RKN), major plant-parasitic pests in global agriculture. To date, breeding for host resistance in cowpea has relied on phenotypic selection which requires time-consuming and expensive controlled infection assays. To facilitate marker-based selection, we aimed to identify and map quantitative trait loci (QTL) conferring the resistance trait. One recombinant inbred line (RIL) and two F2:3 populations, each derived from a cross between a susceptible and a resistant parent, were genotyped with genome-wide single nucleotide polymorphism (SNP) markers. The populations were screened in the field for root-galling symptoms and/or under growth-chamber conditions for nematode reproduction levels using M. incognita and M. javanica biotypes. One major QTL was mapped consistently on linkage group VuLG11 of each population. By genotyping additional cowpea lines and near-isogenic lines derived from conventional backcrossing, we confirmed that the detected QTL co-localized with the genome region associated with the Rk locus for RKN resistance that has been used in conventional breeding for many decades. This chromosomal location defined with flanking markers will be a valuable target in marker-assisted breeding and for positional cloning of genes controlling RKN resistance
Integrability of irrotational silent cosmological models
We revisit the issue of integrability conditions for the irrotational silent
cosmological models. We formulate the problem both in 1+3 covariant and 1+3
orthonormal frame notation, and show there exists a series of constraint
equations that need to be satisfied. These conditions hold identically for
FLRW-linearised silent models, but not in the general exact non-linear case.
Thus there is a linearisation instability, and it is highly unlikely that there
is a large class of silent models. We conjecture that there are no spatially
inhomogeneous solutions with Weyl curvature of Petrov type I, and indicate
further issues that await clarification.Comment: Minor corrections and improvements; 1 new reference; to appear Class.
Quantum Grav.; 16 pages Ioplpp
Dissociative symptoms and the acute stress disorder diagnosis in children and adolescents:A replication of the Harvey and Bryant (1999) study
Acute stress disorder (ASD) is a good predictor of posttraumatic stress disorder in adult populations, although the emphasis on dissociation symptoms within the diagnosis has been questioned. Recent studies suggest that ASD may also have application to children and adolescents. The present study examined properties of ASD within youth. A large (N = 367) multisite sample of 6- to 17-year-old children and adolescents exposed to motor vehicle accidents completed interviews or self-report questionnaires regarding their acute stress symptoms. The study found evidence supporting the suggestion that the dissociative criterion of ASD is excessively strict in youth, and that there is less overlap between dissociative symptoms than in adults. The implications of these findings for how ASD is applied to youth are discussed
The latent structure of Acute Stress Disorder symptoms in trauma-exposed children and adolescents.
BACKGROUND: The revision of Acute Stress Disorder (ASD) in the DSM-5 (DSM-5, 2013) proposes a cluster-free model of ASD symptoms in both adults and youth. Published evaluations of competing models of ASD clustering in youth have rarely been examined. METHODS: We used Confirmatory Factor Analysis (combined with multigroup invariance tests) to explore the latent structure of ASD symptoms in a trauma-exposed sample of children and young people (N = 594). The DSM-5 structure was compared with the previous DSM-IV conceptualization (4-factor), and two alternative models proposed in the literature (3-factor; 5-factor). Model fit was examined using goodness-of-fit indices. We also established DSM-5 ASD prevalence rates relative to DSM-IV ASD, and the ability of these models to classify children impaired by their symptoms. RESULTS: Based on both the Bayesian Information Criterion, the interfactor correlations and invariance testing, the 3-factor model best accounted for the profile of ASD symptoms. DSM-5 ASD led to slightly higher prevalence rates than DSM-IV ASD and performed similarly to DSM-IV with respect to categorising children impaired by their symptoms. Modifying the DSM-5 ASD algorithm to a 3+ or 4+ symptom requirement was the strongest predictor of impairment. CONCLUSIONS: These findings suggest that a uni-factorial general-distress model is not the optimal model of capturing the latent structure of ASD symptom profiles in youth and that modifying the current DSM-5 9+ symptom algorithm could potentially lead to a more developmentally sensitive conceptualization
Predicting the effects of biochar on volatile petroleum hydrocarbon biodegradation and emanation from soil: a bacterial community finger-print analysis inferred modelling approach
We investigated the response of the dominant bacterial taxa in gravelly sand to the addition of biochar and/or mixtures of volatile petroleum hydrocarbons (VPHs) using denaturing gradient gel electrophoresis (DGGE) and sequencing of cut bands. Biochar addition alone had only weak effects on the soil bacterial community composition in batch study samples, while VPH addition had strong effects. Indirect effects of biochar on soil bacterial communities were apparent in column study samples, where biochar-enhanced sorption affected VPH spreading. Following VPH addition, cell abundance increased by no more than a factor of 2 and several Pseudomonas spp. became dominant in soil with and without biochar. We present a VPH fate model that considers soil bacterial biomass dynamics and a nutrient limited soil biomass carrying capacity. The model simulates an apparent lag phase before the onset of a brief period of intensive VPH biodegradation and biomass growth, which is followed by substantially slower VPH biodegradation, when nitrogen needs to be recycled between decaying and newly formed biomass. If biomass growth is limited by a factor other than the organic pollutant bioavailability, biochar amendment may enhance VPH attenuation in between a VPH source below ground and the atmosphere by reducing the risk of overloading the soil's biodegradation capacity
Predictive validity of acute stress disorder in children and adolescents
Adult research suggests that the dissociation criterion of acute stress disorder has limited validity in predicting posttraumatic stress disorder (PTSD). We addressed this issue in child and adolescent survivors (n=367) of road accidents. Dissociation accounted for no significant unique variance in later PTSD, over and above other acute stress disorder criteria. Furthermore, thresholds of either three or more re-experiencing symptoms, or six or more re-experiencing/hyperarousal symptoms, were as effective at predicting PTSD as the full acute stress disorder diagnosis
Targeting Platelet–Leukocyte Interactions: Identification of the Integrin Mac-1 Binding Site for the Platelet Counter Receptor Glycoprotein Ibα
The firm adhesion and transplatelet migration of leukocytes on vascular thrombus are dependent on the interaction of the leukocyte integrin Mac-1 (αMβ2, CD11b/CD18) and the platelet counter receptor glycoprotein (GP) Ibα. Previous studies have established a central role for the I domain, a stretch of ∼200 amino acids within the αM subunit, in the binding of GP Ibα. This study was undertaken to establish the molecular basis of GP Ibα recognition by αMβ2. The P201–K217 sequence, which spans an exposed loop and amphipathic α4 helix in the three-dimensional structure of the αMI domain, was identified as the binding site for GP Ibα. Mutant cell lines in which the αMI domain segments P201–G207 and R208–K217 were switched to the homologous, but non-GP Ibα binding, αL domain segments failed to support adhesion to GP Ibα. Mutation of amino acid residues within P201–K217, H210–A212, T213–I215, and R216–K217 resulted in the loss of the binding function of the recombinant αMI domains to GP Ibα. Synthetic peptides duplicating the P201–K217, but not scrambled versions, directly bound GP Ibα and inhibited αMβ2-dependent adhesion to GP Ibα and adherent platelets. Finally, grafting critical amino acids within the P201–K217 sequence onto αL, converted αLβ2 into a GP Ibα binding integrin. Thus, the P201–K217 sequence within the αMI domain is necessary and sufficient for GP Ibα binding. These observations provide a molecular target for disrupting leukocyte–platelet complexes that promote vascular inflammation in thrombosis, atherosclerosis, and angioplasty-related restenosis
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