Marine Virus-Like Particles and Microbes: A Linear Interpretation

Viruses are key players in ocean ecology and biogeochemistry, not only because of their functional roles but also partially due to their sheer abundance (Fuhrman, 1999; Wilhelm and Suttle, 1999). Because viruses cannot replicate without their hosts’ machinery, their abundance is inextricably related to that of their (mostly microbial) hosts. The relationship between viral and microbial abundances is thus of great interest

Reducing Occupational Distress in Veterinary Medicine Personnel with Acceptance and Commitment Training: A Pilot Study

Aims To determine whether an educational programme targeting the reaction of veterinary personnel to difficult client interactions reduced burden transfer, stress and burnout in veterinary staff. Methods Employees of three small-animal veterinary hospitals in the south-western United States of America were recruited and randomised to intervention (educational programme; n = 16) or control (no intervention; n = 18) groups. Participants of this randomised, parallel arms trial completed pre-programme assessment including the Burden Transfer Inventory (BTI), Perceived Stress Scale, and Copenhagen Burnout Inventory. Assessment was followed by two, group-format educational sessions, based on acceptance and commitment training, tailored to reducing reactivity to difficult veterinary client interactions (intervention group only). After training was completed, both groups were assessed using the same measures and the intervention participants provided use and acceptability ratings. Results Intervention participants rated the programme as useful and appropriate, and reported that programme techniques were used a median of 43 (min 9, max 68) times during the 2 weeks prior to retesting. Relative to pre-programme scores, median post-programme scores for reaction (subscore of BTI) to difficult client interactions decreased in the intervention group (33 vs. 54; p = 0.047), but not in the control group (51 vs. 59; p = 0.210). Changes in median scores for stress and burnout from pre- to post-programme were non-significant for both groups. Conclusions This pilot and feasibility trial showed high rates of acceptability and use by participants, as well as promising reductions in burden transfer. A larger scale clinical trial with follow-up at extended time points is needed to more fully examine the efficacy of this novel programme

Thoracic Epidural analgesia versus Rectus Sheath Catheters for open midline incisions in major abdominal surgery within an enhanced recovery programme (TERSC):study protocol for a randomised controlled trial

BACKGROUND: Thoracic epidural analgesia (TEA) is recommended for post-operative pain relief in patients undergoing major abdominal surgery via a midline incision. However, the effectiveness of TEA is variable with high failure rates reported post-operatively. Common side effects such as low blood pressure and motor block can reduce mobility and hinder recovery, and a number of rare but serious complications can also occur following their use.Rectus sheath catheters (RSC) may provide a novel alternative approach to somatic analgesia without the associated adverse effects of TEA. The aim of this study is to compare the efficacy of both techniques in terms of pain relief, patient experience, post-operative functional recovery, safety and cost-effectiveness. METHODS/DESIGN: This is a single-centre randomised controlled non-blinded trial, which also includes a nested qualitative study. Over a two-year period, 132 patients undergoing major abdominal surgery via a midline incision will be randomised to receive either TEA or RSC for post-operative analgesia. The primary outcome measures pain scores on moving from a supine to a sitting position at 24 hours post wound closure, and the patient experience between groups evaluated through in-depth interviews. Secondary outcomes include pain scores at rest and on movement at other time points, opiate consumption, functional recovery, morbidity and cost-effectiveness. DISCUSSION: This will be the first randomised controlled trial comparing thoracic epidurals to ultrasound-guided rectus sheath catheters in adults undergoing elective midline laparotomy. The standardised care provided by an Enhanced Recovery Programme makes this a comparison between two complex pain packages and not simply two analgesic techniques, in order to ascertain if RSC is a viable alternative to TEA. TRIAL REGISTRATION: Current Controlled Trials ISRCTN81223298 (16 January 2014)

Sampling Weed Spatial Variability on a Fieldwide Scale

Site-specific weed management recommendations require knowledge of weed species, density, and location in the field. This study compared several sampling techniques to estimate weed density and distribution in two 65-ha no-till Zea mays–Glycine max rotation fields in eastern South Dakota. The most common weeds (Setaria viridis, Setaria glauca, Cirsium arvense, Ambrosia artemisiifolia, and Polygonum pensylvanicum) were counted by species in 0.1-m2 areas on a 15- by 30-m (1,352 points in each field) or 30- by 30-m (676 points in each field) grid pattern, and points were georeferenced and data spatially analyzed. Using different sampling approaches, weed populations were estimated by resampling the original data set. The average density for each technique was calculated and compared with the average field density calculated from the all-point data. All weeds had skewed population distributions with more than 60% of sampling points lacking the specific weed, but very high densities (i.e., \u3e 100 plants m−2) were also observed. More than 300 random samples were required to estimate densities within 20% of the all-point means about 60% of the time. Sampling requirement increased as average density decreased. The W pattern produced average species densities that often were similar to the field averages, but information on patch location was absent. Weed counts taken on the 15- by 30-m grid were dependent spatially and weed contour maps were developed. Kriged maps presented both density and location of weed patches and could be used to establish management zones. However, grid-sampling production fields on a small enough scale to obtain spatially dependent data may have limited usefulness because of time, cost, and labor constraints

Vacuum Polarization and Energy Conditions at a Planar Frequency Dependent Dielectric to Vacuum Interface

The form of the vacuum stress-tensor for the quantized scalar field at a dielectric to vacuum interface is studied. The dielectric is modeled to have an index of refraction that varies with frequency. We find that the stress-tensor components, derived from the mode function expansion of the Wightman function, are naturally regularized by the reflection and transmission coefficients of the mode at the boundary. Additionally, the divergence of the vacuum energy associated with a perfectly reflecting mirror is found to disappear for the dielectric mirror at the expense of introducing a new energy density near the surface which has the opposite sign. Thus the weak energy condition is always violated in some region of the spacetime. For the dielectric mirror, the mean vacuum energy density per unit plate area in a constant time hypersurface is always found to be positive (or zero) and the averaged weak energy condition is proven to hold for all observers with non-zero velocity along the normal direction to the boundary. Both results are found to be generic features of the vacuum stress-tensor and not necessarily dependent of the frequency dependence of the dielectric.Comment: 16 pages, 4 figures, Revtex style Minor typographic corrections to equations and tex

Wide-angle elastic scattering and color randomization

Baryon-baryon elastic scattering is considered in the independent scattering (Landshoff) mechanism. It is suggested that for scattering at moderate energies, direct and interchange quark channels contribute with equal color coefficients because the quark color is randomized by soft gluon exchange during the hadronization stage. With this assumption, it is shown that the ratio of cross sections $R_{\overline{p} p/ p p}$ at CM angle $\theta = 90^0$ decreases from a high energy value of R_{\pbar p / pp} \approx 1/2.7, down to R_{\pbar p / pp} \approx 1/28, compatible with experimental data at moderate energies. This sizable fall in the ratio seems to be characteristic of the Landshoff mechanism, in which changes at the quark level have a strong effect precisely because the hadronic process occurs via multiple quark scatterings. The effect of color randomization on the angular distribution of proton-proton elastic scattering and the cross section ratio $R_{np/pp}$ is also discussed.Comment: 18 pages, latex2e, 4 uuencoded figures, include

An x-ray diffraction study of corneal structure in mimecan-deficient mice

PURPOSE: Keratan sulfate proteoglycans (KSPGs) in the corneal stroma are believed to influence collagen fibrillar arrangement. This study was performed to investigate the fibrillar architecture of the corneal stroma in mice homozygous for a null mutation in the corneal KSPG, mimecan. METHODS: Wild-type (n = 9) and mimecan-deficient (n = 10) mouse corneas were investigated by low-angle synchrotron x-ray diffraction to establish the average collagen fibrillar spacing, average collagen fibril diameter, and level of fibrillar organization in the stromal array. RESULTS: The mean collagen fibril diameter in the corneas of mimecan-null mice, as an average throughout the whole thickness of the tissue, was not appreciably different from normal (35.6 +/- 1.1 nm vs. 35.9 +/- 1.0 nm). Average center-to-center collagen fibrillar spacing in the mutant corneas measured 52.6 +/- 2.6 nm, similar to the 53.3 +/- 4.0 nm found in wild-type mice. The degree of local order in the collagen fibrillar array, as indicated by the height-width (H:W) ratio of the background-subtracted interfibrillar x-ray reflection, was also not significantly changed in mimecan-null corneas (23.4 +/- 5.6), when compared with the corneas of wild-types (28.2 +/- 4.8). CONCLUSIONS: On average, throughout the whole depth of the corneal stroma, collagen fibrils in mimecan-null mice, unlike collagen fibrils in lumican-null mice and keratocan-null mice, are of a normal diameter and are normally spaced and arranged. This indicates that, compared with lumican and keratocan, mimecan has a lesser role in the control of stromal architecture in mouse cornea

Evolution of the Far-infrared Cloud at Titan's South Pole

A condensate cloud on Titan identified by its 220 cm (sup -1) far-infrared signature continues to undergo seasonal changes at both the north and south poles. In the north the cloud, which extends from 55 North to the pole, has been gradually decreasing in emission intensity since the beginning of the Cassini mission with a half-life of 3.8 years. The cloud in the south did not appear until 2012 but its intensity has increased rapidly, doubling every year. The shape of the cloud at the South Pole is very different from that in the north. Mapping in December 2013 showed that the condensate emission was confined to a ring with a maximum at 80 South. The ring was centered 4 degrees from Titan's pole. The pattern of emission from stratospheric trace gases like nitriles and complex hydrocarbons (mapped in January 2014) was also offset by 4 degrees, but had a central peak at the pole and a secondary maximum in a ring at about 70 South with a minimum at 80 South. The shape of the gas emissions distribution can be explained by abundances that are high at the atmospheric pole and diminish toward the equator, combined with correspondingly increasing temperatures. We discuss possible causes for the condensate ring. The present rapid build up of the condensate cloud at the South Pole is likely to transition to a gradual decline during 2015-16

Covariant equations for the three-body bound state

The covariant spectator (or Gross) equations for the bound state of three identical spin 1/2 particles, in which two of the three interacting particles are always on shell, are developed and reduced to a form suitable for numerical solution. The equations are first written in operator form and compared to the Bethe-Salpeter equation, then expanded into plane wave momentum states, and finally expanded into partial waves using the three-body helicity formalism first introduced by Wick. In order to solve the equations, the two-body scattering amplitudes must be boosted from the overall three-body rest frame to their individual two-body rest frames, and all effects which arise from these boosts, including the Wigner rotations and rho-spin decomposition of the off-shell particle, are treated exactly. In their final form, the equations reduce to a coupled set of Faddeev-like double integral equations with additional channels arising from the negative rho-spin states of the off-shell particle.Comment: 57 pages, RevTeX, 6 figures, uses epsf.st

Searching for Exoplanets Using a Microresonator Astrocomb

Detection of weak radial velocity shifts of host stars induced by orbiting planets is an important technique for discovering and characterizing planets beyond our solar system. Optical frequency combs enable calibration of stellar radial velocity shifts at levels required for detection of Earth analogs. A new chip-based device, the Kerr soliton microcomb, has properties ideal for ubiquitous application outside the lab and even in future space-borne instruments. Moreover, microcomb spectra are ideally suited for astronomical spectrograph calibration and eliminate filtering steps required by conventional mode-locked-laser frequency combs. Here, for the calibration of astronomical spectrographs, we demonstrate an atomic/molecular line-referenced, near-infrared soliton microcomb. Efforts to search for the known exoplanet HD 187123b were conducted at the Keck-II telescope as a first in-the-field demonstration of microcombs