54 research outputs found
Experimental Verification of the G-H Measurement Model by Ultrasonic Diffraction in Single Crystals, and New [110] Longitudinal Propagation Results
A calculation of diffraction loss versus normalized (dimensionless) distance is needed to correct ultrasonic attenuation measurements for beam spreading and arrive at the intrinsic material attenuation as a function of frequency.</p
Positional Cloning of âLisch-likeâ, a Candidate Modifier of Susceptibility to Type 2 Diabetes in Mice
In 404 Lepob/ob F2 progeny of a C57BL/6J (B6) x DBA/2J (DBA) intercross, we mapped a DBA-related quantitative trait locus (QTL) to distal Chr1 at 169.6 Mb, centered about D1Mit110, for diabetes-related phenotypes that included blood glucose, HbA1c, and pancreatic islet histology. The interval was refined to 1.8 Mb in a series of B6.DBA congenic/subcongenic lines also segregating for Lepob. The phenotypes of B6.DBA congenic mice include reduced ÎČ-cell replication rates accompanied by reduced ÎČ-cell mass, reduced insulin/glucose ratio in blood, reduced glucose tolerance, and persistent mild hypoinsulinemic hyperglycemia. Nucleotide sequence and expression analysis of 14 genes in this interval identified a predicted gene that we have designated âLisch-likeâ (Ll) as the most likely candidate. The gene spans 62.7 kb on Chr1qH2.3, encoding a 10-exon, 646âamino acid polypeptide, homologous to Lsr on Chr7qB1 and to Ildr1 on Chr16qB3. The largest isoform of Ll is predicted to be a transmembrane molecule with an immunoglobulin-like extracellular domain and a serine/threonine-rich intracellular domain that contains a 14-3-3 binding domain. Morpholino knockdown of the zebrafish paralog of Ll resulted in a generalized delay in endodermal development in the gut region and dispersion of insulin-positive cells. Mice segregating for an ENU-induced null allele of Ll have phenotypes comparable to the B.D congenic lines. The human ortholog, C1orf32, is in the middle of a 30-Mb region of Chr1q23-25 that has been repeatedly associated with type 2 diabetes
The mammals of Angola
Scientific investigations on the mammals of Angola started over 150 years
ago, but information remains scarce and scattered, with only one recent published
account. Here we provide a synthesis of the mammals of Angola based on a thorough
survey of primary and grey literature, as well as recent unpublished records. We present
a short history of mammal research, and provide brief information on each species
known to occur in the country. Particular attention is given to endemic and near endemic
species. We also provide a zoogeographic outline and information on the conservation
of Angolan mammals. We found confirmed records for 291 native species, most of
which from the orders Rodentia (85), Chiroptera (73), Carnivora (39), and
Cetartiodactyla (33). There is a large number of endemic and near endemic species,
most of which are rodents or bats. The large diversity of species is favoured by the wide range of habitats with contrasting environmental conditions, while endemism tends to
be associated with unique physiographic settings such as the Angolan Escarpment. The
mammal fauna of Angola includes 2 Critically Endangered, 2 Endangered, 11
Vulnerable, and 14 Near-Threatened species at the global scale. There are also 12 data
deficient species, most of which are endemics or near endemics to the countryinfo:eu-repo/semantics/publishedVersio
Going Through the Rites of Passage: Timing and Transition of Menarche, Childhood Sexual Abuse, and Anxiety Symptoms in Girls
Menarche is a discrete, transitional event that holds considerable personal, social, biological, and developmental significance. The present longitudinal study examined both the transition and timing of menarche on the trajectory of anxiety in girls with histories of childhood maltreatment (NÂ =Â 93; 63% European American, 14% multiracial, 10% Latino, 9% African American, and 4% Native American). We hypothesized that because menarche is a novel, unfamiliar experience, girls would show greater anxiety around the time of menarche. The anxiety-provoking nature of menarche may be accentuated among earlier-maturing girls and girls with histories of childhood sexual abuse. Results indicated that earlier-maturing girls were more anxious in the pre- and peri-menarche periods than their later-maturing peers; however, their anxiety declined after menarche. Childhood sexual abuse was associated with heightened anxiety throughout this transition. The developmental significance of the timing and transition of menarche in relation to childhood sexual abuse and anxiety is discussed
An empirical method for the study of exemplar explanations
The most common way of studying explanations in philosophy of science and science education is through case studies. Recently these have been supplemented with studies based on empirical methods. This chapter provides an empirical method for collecting and comparing exemplar explanations across scientific disciplines with the aim of exposing possible qualitative differences between them. The method is based on the use of science textbooks as sources of explanations. I discuss a number of possible strategies for identifying explanations in these sources, and specify a set of reliable linguistic indicators that can be used for this purpose. A pilot study is presented to illustrate the method and its limitations
Insulin induces long-term depression of ventral tegmental area dopamine neurons via endocannabinoids.
The prevalence of obesity has markedly increased over the past few decades. Exploration of how hunger and satiety signals influence the reward system can help us understand non-homeostatic feeding. Insulin may act in the ventral tegmental area (VTA), a critical site for reward-seeking behavior, to suppress feeding. However, the neural mechanisms underlying insulin effects in the VTA remain unknown. We demonstrate that insulin, a circulating catabolic peptide that inhibits feeding, can induce long-term depression (LTD) of mouse excitatory synapses onto VTA dopamine neurons. This effect requires endocannabinoid-mediated presynaptic inhibition of glutamate release. Furthermore, after a sweetened high-fat meal, which elevates endogenous insulin, insulin-induced LTD is occluded. Finally, insulin in the VTA reduces food anticipatory behavior in mice and conditioned place preference for food in rats. Taken together, these results suggest that insulin in the VTA suppresses excitatory synaptic transmission and reduces anticipatory activity and preference for food-related cues
- âŠ