MEVTV study: Early tectonic evolution of Mars: Crustal dichotomy to Valles Marineris

Several fundamental problems were addressed in the early impact, tectonic, and volcanic evolution of the martian lithosphere: (1) origin and evolution of the fundamental crustal dichotomy, including development of the highland/lowland transition zone; (2) growth and evolution of the Valles Marineris; and (3) nature and role of major resurfacing events in early martian history. The results in these areas are briefly summarized

Face Immersion Bradycardia: Comparison of Swimmer and Nonswimmers

Author Institution: Department of Physiology, Wright State University ; Department of Physiology, George Washington UniversityA profound bradycardia may be exhibited by waterfowl and aquatic mammals when they dive underwater in search of food. A similar response occurs in humans diving underwater or simply wetting the face while breathholding. This bradycardia is mediated by the parasympathetic nervous system (vagus). We investigated whether the extent of this apneic face immersion bradycardia, or bradycardia during dry apnea, is greater in actively training competitive swimmers than in nonswimmers. Eight competitive swimmers and eight age/sex matched nonswimmers each performed apneic face immersion and dry apneic maneuvers while prone. Resting cardiac cycle (interval) duration was not significantly different between these groups, but the swimmers had a significantly longer interval duration (lower heart rate), P<0.05, and a greater percentage decrease of interval duration during both apneic face immersion and dry apnea. Swimmers—but not nonswimmers—demonstrated cardiac arrhythmias considered to be vagally mediated during face immersion. These results indicated that competitive swimmers in active training may have a greater range of parasympathetic nervous system (vagal) control of the heart as well as the well-accepted greater resting level of vagal tone

Optimal flexibility for conformational transitions in macromolecules

Conformational transitions in macromolecular complexes often involve the reorientation of lever-like structures. Using a simple theoretical model, we show that the rate of such transitions is drastically enhanced if the lever is bendable, e.g. at a localized "hinge''. Surprisingly, the transition is fastest with an intermediate flexibility of the hinge. In this intermediate regime, the transition rate is also least sensitive to the amount of "cargo'' attached to the lever arm, which could be exploited by molecular motors. To explain this effect, we generalize the Kramers-Langer theory for multi-dimensional barrier crossing to configuration dependent mobility matrices.Comment: 4 pages, 4 figure

Contrasting Demographic History and Phylogeographic Patterns in Two Indo-Pacific Gastropods

Marine species with ranges that span the Indo-Australian Archipelago (IAA) exhibit a range of phylogeographic patterns, most of which are interpreted in the context of vicariance between Indian and Pacific Ocean populations during Pliocene and Pleistocene low sea level stands. However, patterns often vary among ecologically similar taxa, sometimes even within genera. This study compares phylogeographic patterns in two species of highly dispersive Neritid gastropod, Nerita albicilla and Nerita plicata, with nearly sympatric ranges that span the Indo-Pacific. Mitochondrial COI sequences from \u3e 1000 individuals from 97 sites reveal similar phylogenies in both species (two divergent clades differing by 3.2% and 2.3%, for N. albicilla and N. plicata respectively). However, despite ecological similarity and congeneric status, the two species exhibit phylogeographic discordance, with N. albicilla maintaining reciprocal monophyly of Indian and Pacific Ocean populations, while N. plicata is panmictic between oceans, but displays a genetic cline in the Central Pacific. Although this difference might be explained by qualitatively different demographic histories, parameter estimates from three coalescent models indicate that both species have high levels of gene flow between demes (2Ne m \u3e 75), and share a common history of population expansion that is likely associated with cyclical flooding of continental shelves and island lagoons following low sea level stands. Results indicate that ecologically similar co-distributed species may respond very differently to shared environmental processes, suggesting that relatively minor differences in traits such as pelagic larval duration or microhabitat association may profoundly impact phylogeographic structure

Progression of pulmonary hyperinflation and trapped gas associated with genetic and environmental factors in children with cystic fibrosis

BACKGROUND: Functional deterioration in cystic fibrosis (CF) may be reflected by increasing bronchial obstruction and, as recently shown, by ventilation inhomogeneities. This study investigated which physiological factors (airway obstruction, ventilation inhomogeneities, pulmonary hyperinflation, development of trapped gas) best express the decline in lung function, and what role specific CFTR genotypes and different types of bronchial infection may have upon this process. METHODS: Serial annual lung function tests, performed in 152 children (77 males; 75 females) with CF (age range: 6–18 y) provided data pertaining to functional residual capacity (FRC(pleth), FRC(MBNW)), volume of trapped gas (V(TG)), effective specific airway resistance (sR(eff)), lung clearance index (LCI), and forced expiratory indices (FVC, FEV(1), FEF(50)). RESULTS: All lung function parameters showed progression with age. Pulmonary hyperinflation (FRC(pleth )> 2SDS) was already present in 39% of patients at age 6–8 yrs, increasing to 67% at age 18 yrs. The proportion of patients with V(TG )> 2SDS increased from 15% to 54% during this period. Children with severe pulmonary hyperinflation and trapped gas at age 6–8 yrs showed the most pronounced disease progression over time. Age related tracking of lung function parameters commences early in life, and is significantly influenced by specific CFTR genotypes. The group with chronic P. aeruginosa infection demonstrated most rapid progression in all lung function parameters, whilst those with chronic S. aureus infection had the slowest rate of progression. LCI, measured as an index of ventilation inhomogeneities was the most sensitive discriminator between the 3 types of infection examined (p < 0.0001). CONCLUSION: The relationships between lung function indices, CFTR genotypes and infective organisms observed in this study suggest that measurement of other lung function parameters, in addition to spirometry alone, may provide important information about disease progression in CF

Compassion, Dominance/Submission, and Curled Lips: A Thematic Analysis of Dacryphilic Experience

Paraphilias are often discussed in the psychological literature as pathological problems, yet relatively little research exists that looks into non-pathological paraphilias (i.e., non-normative sexual interests). Empirical evidence suggests that many individuals incorporate a range of non-normative sexual interests into their sexual lifestyles. Dacryphilia is a non-normative sexual interest that involves enjoyment or arousal from tears and crying, and to date has never been researched empirically. The present study set out to discover the different interests within dacryphilia and explore the range of dacryphilic experience. A set of online interviews was carried out with individuals with dacryphilic preferences and interests (six females and two males) from four countries. The data were analysed for semantic and latent themes using thematic analysis. The respondents' statements focused attention on three distinct areas that may be relevant to the experience of dacryphilia: (i) compassion; (ii) dominance/submission; and (iii) curled-lips. The data provided detailed descriptions of features within all three interests, which are discussed in relation to previous quantitative and qualitative research within emotional crying and tears, and the general area of non-normative sexual interests. The study suggests new directions for potential research both within dacryphilia and with regard to other non-normative sexual interests

Tritium labeling of potential lipophilic myelin probes

Two potential lipophilic myelin imaging agents (1,1,2,2‐tetrafluoro‐1,2‐diphenylethane and 1‐fluoroadamantane) were tritium labeled. The most effective method employed the microwave discharge activation of tritium gas technique and resulted in specific activities of 177 mCi/mmol for 1,1,2,2‐tetrafluoro‐1,2‐diphenylethane and 593 mCi/mmol for 1‐fluoroadamantane. Using this tritiation method significant amounts of tritium‐for‐fluorine substitution was also observed in the labeling of 1‐fluoroadamatane, resulting in nearly equivalent amounts of tritiated adamantane and fluoroadamantane.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90398/1/2580210110_ftp.pd

State based model of long-term potentiation and synaptic tagging and capture

Recent data indicate that plasticity protocols have not only synapse-specific but also more widespread effects. In particular, in synaptic tagging and capture (STC), tagged synapses can capture plasticity-related proteins, synthesized in response to strong stimulation of other synapses. This leads to long-lasting modification of only weakly stimulated synapses. Here we present a biophysical model of synaptic plasticity in the hippocampus that incorporates several key results from experiments on STC. The model specifies a set of physical states in which a synapse can exist, together with transition rates that are affected by high- and low-frequency stimulation protocols. In contrast to most standard plasticity models, the model exhibits both early- and late-phase LTP/D, de-potentiation, and STC. As such, it provides a useful starting point for further theoretical work on the role of STC in learning and memory

Combined ultrasound and photoacoustic imaging of metal objects

Methods of combined ultrasound and photoacoustic imaging are provided. In some embodiments, the methods may be used to determine the location or positioning of a metal object in a sample. In other embodiments, the methods may be used to determine the composition of a sample surrounding a metal object. Other methods are also provided.Board of Regents, University of Texas Syste

The Prevalence and Volumetry of Pituitary Cysts in Children with Growth Hormone Deficiency and Idiopathic Short Stature

Background Pituitary cysts have been speculated to cause endocrinopathies. We sought to describe the prevalence and volumetry of pituitary cysts in patients with growth hormone deficiency (GHD) and idiopathic short stature (ISS). Methods Six hundred and eighteen children evaluated for growth failure at the Division of Pediatric Endocrinology at New York Medical College between the years 2002 and 2012, who underwent GH stimulation testing and had a brain magnetic resonance imaging (MRI) prior to initiating GH treatment were randomly selected to be a part of this study. High resolution MRI was used to evaluate the pituitary gland for size and the presence of a cyst. Cyst prevalence, cyst volume and percentage of the gland occupied by the cyst (POGO) were documented. Results Fifty-six patients had a cyst, giving an overall prevalence of 9.1%. The prevalence of cysts in GHD patients compared to ISS patients was not significant (13.5% vs. 5.7%, p=0.46). Mean cyst volume was greater in GHD patients than ISS patients (62.0 mm3 vs. 29.4 mm3, p=0.01). POGO for GHD patients was significantly greater (p=0.003) than for ISS patients (15.3%+/-12.8 vs. 7.1%+/-8.0). Observers were blinded to patient groups. Conclusions GHD patients had a significantly greater volume and POGO compared to ISS patients. This raises the question of whether cysts are implicated in the pathology of growth failure