Tidal evolution of close-in giant planets : Evidence of Type II migration?

It is well accepted that 'hot Jupiters' did not form in situ, as the temperature in the protoplanetary disc at the radius at which they now orbit would have been too high for planet formation to have occurred. These planets, instead, form at larger radii and then move into the region in which they now orbit. The exact process that leads to the formation of these close-in planets is, however, unclear and it seems that there may be more than one mechanism that can produce these short-period systems. Dynamical interactions in multiple-planet systems can scatter planets into highly eccentric orbits which, if the pericentre is sufficiently close to the parent star, can be tidally circularised by tidal interactions between the planet and star. Furthermore, systems with distant planetary or stellar companions can undergo Kozai cycles which can result in a planet orbiting very close to its parent star. However, the most developed model for the origin of short period planets is one in which the planet exchanges angular momentum with the surrounding protoplanetary disc and spirals in towards the central star. In the case of 'hot Jupiters', the planet is expected to open a gap in the disc and migrate through Type II .migration. If this is the dominant mechanism for producing `hot Jupiters' then we would expect the currect properties of observed close-in giant planets to be consistent with an initial population resulting from Type II migration followed by evolution due to tidal interactions with the central star. We consider initial distributions that are consistent with Type II migration and find that after tidal evolution, the final distributions can be consistent with that observed. Our results suggest that a modest initial pile-up at a ~ 0.05 au is required and that the initial eccentricity distribution must peak at e \sim 0.Comment: 10 pages, 15 figures, accepted for publication in Monthly Notices of the Royal Astronomical Societ

Effectiveness of a comprehensive mental skills curriculum in enhancing surgical performance: Results of a randomized controlled trial

INTRODUCTION: We hypothesized that the implementation of a novel mental skills curriculum (MSC) during laparoscopic simulator training would improve mental skills and performance, and decrease stress. METHODS: Sixty volunteer novices were randomized into intervention and control groups. All participants received FLS training while the intervention group also participated in the MSC. Skill transfer and retention were assessed on a live porcine model after training and 2 months later, respectively. Performance was assessed using the Test of Performance Strategies-2 (TOPS-2) for mental skills, FLS metrics for laparoscopic performance, and the State Trait Anxiety Inventory (STAI-6) and heart rate (HR) for stress. RESULTS: Fifty-five participants (92%) completed training and the transfer test, and 46 (77%) the retention test. There were no significant differences between groups at baseline. Compared to controls the intervention group significantly improved their mental skill use, demonstrated higher laparoscopic skill improvement during retention, and reported less stress during the transfer test. CONCLUSIONS: The MSC implemented in this study effectively enhanced participants' mental skill use, reduced cognitive stress in the operating room with a small impact on laparoscopic performance

A multidomain hub anchors the chromosome segregation and chemotactic machinery to the bacterial pole

The cell poles constitute key subcellular domains that are often critical for motility, chemotaxis, and chromosome segregation in rod-shaped bacteria. However, in nearly all rods, the processes that underlie the formation, recognition, and perpetuation of the polar domains are largely unknown. Here, in Vibrio cholerae, we identified HubP (hub of the pole), a polar transmembrane protein conserved in all vibrios, that anchors three ParA-like ATPases to the cell poles and, through them, controls polar localization of the chromosome origin, the chemotactic machinery, and the flagellum. In the absence of HubP, oriCI is not targeted to the cell poles, chemotaxis is impaired, and a small but increased fraction of cells produces multiple, rather than single, flagella. Distinct cytoplasmic domains within HubP are required for polar targeting of the three ATPases, while a periplasmic portion of HubP is required for its localization. HubP partially relocalizes from the poles to the mid-cell prior to cell division, thereby enabling perpetuation of the polar domain in future daughter cells. Thus, a single polar hub is instrumental for establishing polar identity and organization

Prevalence and Distribution of Ranavirus in Amphibians From

Several infectious diseases are threatening amphibian species worldwide and have resulted in massmortality events across the globe. An emerging group of viral pathogens (ranaviruses) are documented to cause die-offs in amphibian populations worldwide, including in several regions of the U.S. Unfortunately, large gaps remain in our understanding of the distribution of this systemic pathogen in the U.S., including within the state of Oklahoma. To address this gap in our understanding, we carried out surveys of this infectious pathogen across 14 sites in seven southeastern Oklahoma counties in spring 2015, screening 17 amphibian species from this region. Using liver and tail tissue samples collected from individual amphibians, we screened for the presence and infection load of ranavirus. Of the 390 samples, 84 (21.5%) tested positive for ranavirus, with infection prevalence varying among species surveyed. Notably, the family Bufonidae had no samples that tested positive for ranavirus, whereas the remaining families had an infection prevalence ranging from 14–50%. Despite an overall infection prevalence of 21.5%, we detected no clinical signs of ranavirosis and all sampled individuals appeared outwardly healthy. These results provide data on the geographic and host distribution of ranavirus in southeastern Oklahoma, as well as the first documented cases of the pathogen in three species of anurans: Gastrophryne carolinensis (Eastern Narrow-mouthed Toad), G. olivacea (Western Narrow-mouthed Toad), and Pseudacris fouquettei (Cajun Chorus Frog). With widespread ranavirus infection, there is potential for transmission from abundant, widespread species to more vulnerable, state-threatened amphibians

Likelihood inference for exponential-trawl processes

Integer-valued trawl processes are a class of serially correlated, stationary and infinitely divisible processes that Ole E. Barndorff-Nielsen has been working on in recent years. In this Chapter, we provide the first analysis of likelihood inference for trawl processes by focusing on the so-called exponential-trawl process, which is also a continuous time hidden Markov process with countable state space. The core ideas include prediction decomposition, filtering and smoothing, complete-data analysis and EM algorithm. These can be easily scaled up to adapt to more general trawl processes but with increasing computation efforts.Comment: 29 pages, 6 figures, forthcoming in: "A Fascinating Journey through Probability, Statistics and Applications: In Honour of Ole E. Barndorff-Nielsen's 80th Birthday", Springer, New Yor

Divergent mathematical treatments in utility theory

In this paper I study how divergent mathematical treatments affect mathematical modelling, with a special focus on utility theory. In particular I examine recent work on the ranking of information states and the discounting of future utilities, in order to show how, by replacing the standard analytical treatment of the models involved with one based on the framework of Nonstandard Analysis, diametrically opposite results are obtained. In both cases, the choice between the standard and nonstandard treatment amounts to a selection of set-theoretical parameters that cannot be made on purely empirical grounds. The analysis of this phenomenon gives rise to a simple logical account of the relativity of impossibility theorems in economic theory, which concludes the paper

Community Education on MTM Services

Background: Medication nonadherence, defined as “the number of doses not taken or taken incorrectly that jeopardizes the patient’s therapeutic outcome,” is a major health problem with about 43% of the general population nonadherent to their medications. Medication nonadherence accounts for an estimated 125,000 deaths per year in the US, 33-69% of medication-related hospital readmissions, and an estimated $100 to$300 billion in direct and indirect medical costs. Medication therapy management (MTM), defined as “a distinct service or group of services that optimize therapeutic outcomes for individual patients,” has been found to reduce medication nonadherence. However, many individuals eligible for MTM services are not aware of the resource available to them and do not believe the service will be beneficial to them. Objectives: A pre post observational study design will be used to determine the effects of two types of educational interventions on MTM of patient’s perceptions of MTM and enrollment in MTM services. Methodology: Participants will be divided into two intervention groups. All participants will complete a pre survey to assess current perceptions of MTM services. One group will attend a community educational event on MTM, and the second group will receive an educational brochure in the mail. All participants will complete a post survey to reassess perceptions of MTM after the educational intervention. In addition, all participants will be tracked to determine future enrollment in an MTM service. Analysis: Descriptive tests and paired t-tests/Wilcoxon Signed Rank tests will be run on data acquired from pre and post surveys. Unpaired t-tests/Mann Whitney and chi-square tests will be run to compare data between intervention groups. Descriptive tests will be run on data acquired from tracking enrollment

Planet Formation in the Outer Solar System

This paper reviews coagulation models for planet formation in the Kuiper Belt, emphasizing links to recent observations of our and other solar systems. At heliocentric distances of 35-50 AU, single annulus and multiannulus planetesimal accretion calculations produce several 1000 km or larger planets and many 50-500 km objects on timescales of 10-30 Myr in a Minimum Mass Solar Nebula. Planets form more rapidly in more massive nebulae. All models yield two power law cumulative size distributions, N_C propto r^{-q} with q = 3.0-3.5 for radii larger than 10 km and N_C propto r^{-2.5} for radii less than 1 km. These size distributions are consistent with observations of Kuiper Belt objects acquired during the past decade. Once large objects form at 35-50 AU, gravitational stirring leads to a collisional cascade where 0.1-10 km objects are ground to dust. The collisional cascade removes 80% to 90% of the initial mass in the nebula in roughly 1 Gyr. This dust production rate is comparable to rates inferred for alpha Lyr, beta Pic, and other extrasolar debris disk systems.Comment: invited review for PASP, March 2002. 33 pages of text and 12 figure

Duration of Nocturnal Hypoglycemia Before Seizures

OBJECTIVE—Despite a high incidence of nocturnal hypoglycemia documented by the use of continuous glucose monitoring (CGM), there are no reports in the literature of nocturnal hypoglycemic seizures while a patient is wearing a CGM device

The Physics of turbulent and dynamically unstable Herbig-Haro jets

The overall properties of the Herbig-Haro objects such as centerline velocity, transversal profile of velocity, flow of mass and energy are explained adopting two models for the turbulent jet. The complex shapes of the Herbig-Haro objects, such as the arc in HH34 can be explained introducing the combination of different kinematic effects such as velocity behavior along the main direction of the jet and the velocity of the star in the interstellar medium. The behavior of the intensity or brightness of the line of emission is explored in three different cases : transversal 1D cut, longitudinal 1D cut and 2D map. An analytical explanation for the enhancement in intensity or brightness such as usually modeled by the bow shock is given by a careful analysis of the geometrical properties of the torus.Comment: 17 pages, 10 figures. Accepted for publication in Astrophysics & Spac