Results of borehole televiewer observations in the Celebes and Sulu Seas

Journal ArticleBorehole televiewer data were collected during Ocean Drilling Program Leg 124 to investigate stress orientations in the Sulu and Celebes sea basins. At Site 768C, in the Sulu Sea, televiewer logs were collected from 809-870 and 950-1250 meters below sea floor (mbsf). At Site 770C, in the Celebes Sea, televiewer logs were collected between 405-524 mbsf. No borehole breakouts were found during examination of these data. Calculation of the allowable stresses using a range of basaltic rock strengths shows that ambient stresses at the depths logged are lower than those necessary to cause breakouts in basalt. Analysis of fractures visible in the borehole televiewer logs showed strong groupings of fracture orientations at both sites. At Site 768, the main fracture trend is N 120? E, dipping 60? SW, with smaller groupings at N 117? E, 62? NE; N 64? E, 68? SE; and N 35? E, 64? E. At Site 770, the main fracture orientations are N 119? E, 68? NE and N 143? E, 70? SW. The preferred orientations of these high-angle fractures may represent a response to the present stress field, either by formation of new fractures or reactivation of older zones of weakness. The observed fracture pattern is compatible with extensional stresses related to subduction at the Cotabato and Negros trenches. Alternatively, the fractures may be relict features recording earlier stress conditions

Demystifying Airline Syncope

Syncope forms a major part of medical in-flight emergencies contributing one-in-four in-flight medical events accounting to 70% of flight diversions. In such patients, it is important to elucidate the pathophysiology of syncope prior to diversion. Postural hypotension is the most common etiology of in-flight syncopal events. However, individuals without any underlying autonomic dysfunction can still experience syncope from hypoxia also known as airline syncope. Initial steps in managing such patients include positioning followed by the airway, breathing and circulation of resuscitation. These interventions need to be in close coordination with ground control to determine decision for flight diversion. Interventions which have been tried for prevention include mental challenge and increased salt and fluid intake. The current paper enhances the understanding of airline syncope by summarizing the associated pathophysiologic mechanisms and the management medical personnel can initiate with limited resources

Ecophylogenetic Characterization of the Gut Microbiome of At-risk Companion and Food Animals

Agricultural and companion animals are integral to our way of life as they provide us with nourishment, financial resources, transportation, and companionship. However, pets, managed animals in the agricultural industry, as well as wild populations of food animals are all subject to health and mortality risks. The gut microbiome is a vital component of animal health and plays a role in immunity, digestion, vitamin synthesis, and behavior. Understanding more about the gut microbiome of managed animals and pets will better inform scientists on how we can amplify these gut microbial benefits and mitigate adverse health consequences in these animals. The overarching objective of the work discussed in this dissertation was to define how the composition of the gut microbiome varies in association with companion and food animal behavior, ecology, and management that underlies their vulnerability in society and nature. After introducing the scope of the problems these animals face and the rationale for investigating their microbiomes in Chapter 2, this dissertation presents the results of a study of the canine gut microbiome, which found, for the first time, that aggressive behavior in dogs links to the composition of their gut microbiome. This research indicates that the gut microbiome may be a potential resource for predicting aggressive tendencies in a dog, which in turn may help prevent or manage the types of behaviors that can result in canine euthanasia. In Chapter 3, this dissertation uniquely describes how the rainbow trout gut microbial community changes after a daily, two week long antibiotic regimen using high throughput in situ 16S rRNA gene sequencing. This research shows that the frequently used aquaculture antibiotic, oxytetracycline, disrupts the rainbow trout gut microbiome, which may have long-lasting impacts on trout health. In Chapter 4, this dissertation documents how the gut microbiome of steelhead varies as a function of geography and experience with hatchery management. This work highlights discoveries on how the wild and hatchery fish gut microbiome varies based on environment and presents possibilities for microbial manipulation that may mitigate declining steelhead populations. A novel aspect of the methodology presented in this dissertation was the use of ecophylogenetic approaches to study the taxonomic composition of the gut microbiome. Specifically, the research presented here identifies monophyletic clades of gut bacteria that manifest robust associations with study covariates, which implies that the clade of bacteria in question evolved conserved biological traits that underlie the association. Consequently, the results presented here potentiate future studies that clarify the molecular mechanisms that define the observed associations. These results document gut microbial changes within agricultural and companion animals that may have consequences for host health, but could be manipulated using probiotic or diagnostics clades to improve animal health and conservation efforts. Ultimately, this dissertation lays the foundation for utilizing knowledge of the gut microbiome to find solutions for improving animal health in veterinary, aquaculture, or natural settings

The Arecibo Arp 220 Spectral Census I: Discovery of the Pre-Biotic Molecule Methanimine and New Cm-wavelength Transitions of Other Molecules

An on-going Arecibo line search between 1.1 and 10 GHz of the prototypical starburst/megamaser galaxy, Arp 220, has revealed a spectrum rich in molecular transitions. These include the ``pre-biotic'' molecules: methanimine (CH$_{2}$NH) in emission, three $v_{2}=1$ direct l-type absorption lines of HCN, and an absorption feature likely to be from either $^{18}$OH or formic acid (HCOOH). In addition, we report the detection of two, possibly three, transitions of $\lambda$4-cm excited OH not previously detected in Arp~220 which are seen in absorption, and a possible absorption feature from the 6.668-GHz line of methanol. This marks the first distant extragalactic detection of methanimine, a pre-biotic molecule. Also, if confirmed, the possible methanol absorption line presented here would represent the first extragalactic detection of methanol at a distance further than 10 Mpc. In addition, the strong, previously undetected, cm-wave HCN $v_{2}=1$ direct l-type lines will aid the study of dense molecular gas and active star-forming regions in this starburst galaxy.Comment: 25 pages, 10 figures. Accepted for publication in A

The gut microbiome correlates with conspecific aggression in a small population of rescued dogs (Canis familiaris)

Aggression is a serious behavioral disorder in domestic dogs that endangers both dogs and humans. The underlying causes of canine aggression are poorly resolved and require illumination to ensure effective therapy. Recent research links the compositional diversity of the gut microbiome to behavioral and psychological regulation in other mammals, such as mice and humans. Given these observations, we hypothesized that the composition of the canine gut microbiome could associate with aggression. We analyzed fecal microbiome samples collected from a small population of pit bull type dogs seized from a dogfighting organization. This population included 21 dogs that displayed conspecific aggressive behaviors and 10 that did not. Beta-diversity analyses support an association between gut microbiome structure and dog aggression. Additionally, we used a phylogenetic approach to resolve specific clades of gut bacteria that stratify aggressive and non-aggressive dogs, including clades within Lactobacillus, Dorea, Blautia, Turicibacter, and Bacteroides. Several of these taxa have been implicated in modulating mammalian behavior as well as gastrointestinal disease states. Although sample size limits this study, our findings indicate that gut microorganisms are linked to dog aggression and point to an aggression-associated physiological state that interacts with the gut microbiome. These results also indicate that the gut microbiome may be useful for diagnosing aggressive behaviors prior to their manifestation and potentially discerning cryptic etiologies of aggression

Tops and Writhing DNA

The torsional elasticity of semiflexible polymers like DNA is of biological significance. A mathematical treatment of this problem was begun by Fuller using the relation between link, twist and writhe, but progress has been hindered by the non-local nature of the writhe. This stands in the way of an analytic statistical mechanical treatment, which takes into account thermal fluctuations, in computing the partition function. In this paper we use the well known analogy with the dynamics of tops to show that when subjected to stretch and twist, the polymer configurations which dominate the partition function admit a local writhe formulation in the spirit of Fuller and thus provide an underlying justification for the use of Fuller's "local writhe expression" which leads to considerable mathematical simplification in solving theoretical models of DNA and elucidating their predictions. Our result facilitates comparison of the theoretical models with single molecule micromanipulation experiments and computer simulations.Comment: 17 pages two figure

Inoculation route-dependent Lassa virus dissemination and shedding dynamics in the natural reservoir – Mastomys natalensis

Lassa virus (LASV), a Risk Group-4 zoonotic haemorrhagic fever virus, affects sub-Saharan African countries. Lassa fever, caused by LASV, results in thousands of annual deaths. Although decades have elapsed since the identification of the Natal multimammate mouse (Mastomys natalensis) as a natural reservoir of LASV, little effort has been made to characterize LASV infection in its reservoir. The natural route of infection and transmission of LASV within M. natalensis remains unknown, and the clinical impact of LASV in M. natalensis is mostly undescribed. Herein, using an outbred colony of M. natalensis, we investigate the replication and dissemination dynamics of LASV in this reservoir following various inoculation routes. Inoculation with LASV, regardless of route, resulted in a systemic infection and accumulation of abundant LASV-RNA in many tissues. LASV infection in the Natal multimammate mice was subclinical, however, clinical chemistry values were transiently altered and immune infiltrates were observed histologically in lungs, spleens and livers, indicating a minor disease with coordinated immune responses are elicited, controlling infection. Intranasal infection resulted in unique virus tissue dissemination dynamics and heightened LASV shedding, compared to subcutaneous inoculation. Our study provides important insights into LASV infection in its natural reservoir using a contemporary infection system, demonstrating that specific inoculation routes result in disparate dissemination outcomes, suggesting intranasal inoculation is important in the maintenance of LASV in the natural reservoir, and emphasizes that selection of the appropriate inoculation route is necessary to examine aspects of viral replication, transmission and responses to zoonotic viruses in their natural reservoirs.Peer Reviewe

Optimal Traffic Networks

Inspired by studies on the airports' network and the physical Internet, we propose a general model of weighted networks via an optimization principle. The topology of the optimal network turns out to be a spanning tree that minimizes a combination of topological and metric quantities. It is characterized by a strongly heterogeneous traffic, non-trivial correlations between distance and traffic and a broadly distributed centrality. A clear spatial hierarchical organization, with local hubs distributing traffic in smaller regions, emerges as a result of the optimization. Varying the parameters of the cost function, different classes of trees are recovered, including in particular the minimum spanning tree and the shortest path tree. These results suggest that a variational approach represents an alternative and possibly very meaningful path to the study of the structure of complex weighted networks.Comment: 4 pages, 4 figures, final revised versio

Calculations of the A_1 phonon frequency in photoexcited Tellurium

Calculations of the A_1 phonon frequency in photoexcited tellurium are presented. The phonon frequency as a function of photoexcited carrier density and phonon amplitude is determined. Recent pump probe experiments are interpreted in the light of these calculatons. It is proposed that, in conjunction with measurements of the phonon period in ultra-fast pump-probe reflectivity experiments, the calculated frequency shifts can be used to infer the evolution of the density of photoexcited carriers on a sub-picosecond time-scale.Comment: 15 pages Latex, 3 postscript figure