Spontaneous Lorentz Violation and the Long-Range Gravitational Preferred-Frame Effect

Lorentz-violating operators involving Standard Model fields are tightly constrained by experimental data. However, bounds are more model-independent for Lorentz violation appearing in purely gravitational couplings. The spontaneous breaking of Lorentz invariance by the vacuum expectation value of a vector field selects a universal rest frame. This affects the propagation of the graviton, leading to a modification of Newton's law of gravity. We compute the size of the long-range preferred-frame effect in terms of the coefficients of the two-derivative operators in the low-energy effective theory that involves only the graviton and the Goldstone bosons.Comment: 11 pages, no figures, revtex4. v4: Replaced to match version to appear in Phys. Lett. B (minor corrections of form

Analysis of environmental influences in nuclear half-life measurements exhibiting time-dependent decay rates

In a recent series of papers evidence has been presented for correlations between solar activity and nuclear decay rates. This includes an apparent correlation between Earth-Sun distance and data taken at Brookhaven National Laboratory (BNL), and at the Physikalisch-Technische Bundesanstalt (PTB). Although these correlations could arise from a direct interaction between the decaying nuclei and some particles or fields emanating from the Sun, they could also represent an "environmental" effect arising from a seasonal variation of the sensitivities of the BNL and PTB detectors due to changes in temperature, relative humidity, background radiation, etc. In this paper, we present a detailed analysis of the responses of the detectors actually used in the BNL and PTB experiments, and show that sensitivities to seasonal variations in the respective detectors are likely too small to produce the observed fluctuations

Natural history and ecological effects on the establishment and fate of Florida carpenter ant cadavers infected by the parasitic manipulator Ophiocordyceps camponoti‐floridani

Ophiocordyceps fungi manipulate the behaviour of their ant hosts to produce a summit disease phenotype, thereby establishing infected ant cadavers onto vegetation at elevated positions suitable for fungal growth and transmission. Multiple environmental and ecological factors have been proposed to shape the timing, positioning and outcome of these manipulations. We conducted a long-term field study of Ophiocordyceps camponoti-floridani infections of Camponotus floridanus ants—the Florida zombie ants. We propose and refine hypotheses on the factors that shape infection outcomes by tracking the occurrence of and fungal growth from hundreds of ant cadavers. We modelled and report these data in relation to weather, light, vegetation and attack by hyperparasites. We investigated environmental factors that could affect the occurrence and location of newly manipulated ant cadavers. New cadaver occurrence was preferentially biased towards epiphytic Tillandsia bromeliads, canopy openness and summer weather conditions (an interactive effect of temperature, humidity and precipitation). Furthermore, we suggest that incident light at the individual cadaver level reflects microhabitat choice by manipulated ants or selective pressure on cadaver maintenance for conditions that improve fungal survival. We also asked which environmental conditions affect fungal fitness. Continued fungal development of reproductive structures and putative transmission increased with moist weather conditions (interaction of humidity and precipitation) and canopy openness, while being reduced by hyperparasitic mycoparasite infections. Moreover, under the most open canopy conditions, we found an atypical Ophiocordyceps growth morphology that could represent a plastic response to conditions influenced by high light levels. Taken together, we explore general trends and the effects of various ecological conditions on host and parasite disease outcomes in the Florida zombie ant system. These insights from the field can be used to inform experimental laboratory setups that directly test the effects of biotic and abiotic factors on fungus–ant interactions or aim to uncover underlying molecular mechanisms. Read the free Plain Language Summary for this article on the Journal blog

Learning words in space and time: Contrasting models of the suspicious coincidence effect

In their 2007b Psychological Review paper, Xu and Tenenbaum found that early word learning follows the classic logic of the “suspicious coincidence effect:” when presented with a novel name (‘fep’) and three identical exemplars (three Labradors), word learners generalized novel names more narrowly than when presented with a single exemplar (one Labrador). Xu and Tenenbaum predicted the suspicious coincidence effect based on a Bayesian model of word learning and demonstrated that no other theory captured this effect. Recent empirical studies have revealed, however, that the effect is influenced by factors seemingly outside the purview of the Bayesian account. A process-based perspective correctly predicted that when exemplars are shown sequentially, the effect is eliminated or reversed (Spencer, Perone, Smith, & Samuelson, 2011). Here, we present a new, formal account of the suspicious coincidence effect using a generalization of a Dynamic Neural Field (DNF) model of word learning. The DNF model captures both the original finding and its reversal with sequential presentation. We compare the DNF model's performance with that of a more flexible version of the Bayesian model that allows both strong and weak sampling assumptions. Model comparison results show that the dynamic field account provides a better fit to the empirical data. We discuss the implications of the DNF model with respect to broader contrasts between Bayesian and process-level models

Proposed instrumentation for PILOT

PILOT (the Pathfinder for an International Large Optical Telescope) is a proposed Australian/European optical/infrared telescope for Dome C on the Antarctic Plateau, with target first light in 2012. The proposed telescope is 2.4m diameter, with overall focal ratio f/10, and a 1 degree field-of-view. In median seeing conditions, it delivers 0.3" FWHM widefield image quality, from 0.7-2.5 microns. In the best quartile of conditions, it delivers diffraction-limited imaging down to 1 micron, or even less with lucky imaging. The areas where PILOT offers the greatest advantages over existing ground-based telescopes are (a) very high resolution optical imaging, (b) high resolution wide-field optical imaging, and (c) all wide-field thermal infrared imaging. The proposed first generation instrumentation consists of (a) a fast, lownoise camera for diffraction-limited optical lucky imaging; (b) a gigapixel optical camera for seeing-limited imaging over a 1 degree field; (c) a 4K × 4K near-infrared (1-5 micron) camera with both wide-field and diffraction-limited modes; and (d) a double-beamed mid-infrared (7-40 micron) imaging spectrograph

Transitioning from manual to stirred-tank bioreactor manufacturing of IDCT, An allogeneiccell therapy to treat lumbar degenerative disc disease

DiscGenics is a clinical stage regenerative medicine company focused on developing cell therapies that alleviate pain and restore function in patients with degenerative disc disease (DDD), a major cause of low back pain which is a driver of disability worldwide. The Company’s lead product candidate, IDCT, is a homologous, allogeneic, off-the-shelf, injectable cell therapy under investigational use in the US (ClinicalTrials.gov Identifier: NCT03347708). The manufacturing process for IDCT involves isolating cells from donated intervertebral disc tissue and expanding them into proprietary progenitor cells known as discogenic cells. For preclinical and early clinical testing, cell production was a manual process which relied on pooling individual flasks to achieve the desired lot size. For successful scale-up and commercial production, DiscGenics seeks to modify the IDCT manufacturing process to utilize one large, single vessel per lot, while also applying bioprocess controls and more robust analytical methods to ensure consistent and optimal production of drug product. Once these changes are implemented, the product critical quality attributes (CQAs) must be maintained. DiscGenics has engaged GE Healthcare (GEHC) and the Centre for Commercialization of Regenerative Medicine (CCRM) for assay, media, and process development at the Centre for Advanced Therapeutic Cell Technologies (CATCT) in Toronto, ON., Canada. In partnership with the Federal Economic Development Agency for Southern Ontario (FedDev Ontario), CATCT accelerates the development, industrialization, and adoption of cell manufacturing technologies to improve patient access to cell and gene therapies. In this collaborative project, discogenic cells were generated in traditional static culture using CellStacks (Corning), in PBS-MINI bioreactor systems (PBS Biotech), and in stirred-tank reactors (STRs) (Eppendorf), which was led by the GEHC/CCRM team. Parameters such as cell viability, fold growth, and identity via flow cytometry were compared across modalities. For the STRs, multiple control parameters were evaluated to improve cell growth and assess successful maintenance of a consistent environment for cell quality. In this study, we found that we are able to maintain CQAs between the production modalities, with cell growth being significantly improved in the STR platform. In the STRs, in-process measurements of metabolites aligned with cell growth found using a custom sampling method. Increased cell expansion was facilitated by modified agitation, inoculation, and perfusion feeding strategies. Additionally, the process-controlled STRs provide non-invasive, continuous process data monitoring which allow for development of specified control ranges of manufacturing parameters. The quality by design (QbD) approach taken for the STR process development and improvement has allowed an increase in the lot size, process knowledge, and data-driven process definition. This presentation describes the approach and benefits of transitioning from a manual process to a suspension-based, process-controlled, stirred-tank reactor to produce allogeneic cell therapies

Evolution of the Clustering of Photometrically Selected SDSS Galaxies

We measure the angular auto-correlation functions (w) of SDSS galaxies selected to have photometric redshifts 0.1 < z < 0.4 and absolute r-band magnitudes Mr < -21.2. We split these galaxies into five overlapping redshift shells of width 0.1 and measure w in each subsample in order to investigate the evolution of SDSS galaxies. We find that the bias increases substantially with redshift - much more so than one would expect for a passively evolving sample. We use halo-model analysis to determine the best-fit halo-occupation-distribution (HOD) for each subsample, and the best-fit models allow us to interpret the change in bias physically. In order to properly interpret our best-fit HODs, we convert each halo mass to its z = 0 passively evolved bias (bo), enabling a direct comparison of the best-fit HODs at different redshifts. We find that the minimum halo bo required to host a galaxy decreases as the redshift decreases, suggesting that galaxies with Mr < -21.2 are forming in halos at the low-mass end of the HODs over our redshift range. We use the best-fit HODs to determine the change in occupation number divided by the change in mass of halos with constant bo and we find a sharp peak at bo ~ 0.9 - corresponding to an average halo mass of ~ 10^12Msol/h. We thus present the following scenario: the bias of galaxies with Mr < -21.2 decreases as the Universe evolves because these galaxies form in halos of mass ~ 10^12Msol/h (independent of redshift), and the bias of these halos naturally decreases as the Universe evolves.Comment: 17 pages, 14 figures, matches version accepted for publication in MNRA

Public health surveillance in the UK revolutionises our understanding of the invasive Salmonella Typhimurium epidemic in Africa

Background:The ST313 sequence type ofSalmonellaTyphimurium causes invasive non-typhoidal salmonellosis and wasthought to be confined to sub-Saharan Africa. Two distinct phylogenetic lineages of African ST313 have been identified.Methods:We analysed the whole genome sequences ofS. Typhimurium isolates from UK patients that weregenerated following the introduction of routine whole-genome sequencing (WGS) ofSalmonella entericabyPublic Health England in 2014.Results:We found that 2.7% (84/3147) ofS. Typhimurium from patients in England and Wales were ST313 and wereassociated with gastrointestinal infection. Phylogenetic analysis revealed novel diversity of ST313 that distinguishedUK-linked gastrointestinal isolates from African-associated extra-intestinal isolates. The majority of genome degradationof African ST313 lineage 2 was conserved in the UK-ST313, but the African lineages carried a characteristic prophageand antibiotic resistance gene repertoire. These findings suggest that a strong selection pressure exists for certainhorizontally acquired genetic elements in the African setting. One UK-isolated lineage 2 strain that probably originatedin Kenya carried a chromosomally locatedblaCTX-M-15, demonstrating the continual evolution of this sequence type inAfrica in response to widespread antibiotic usage.Conclusions:The discovery of ST313 isolates responsible for gastroenteritis in the UK reveals new diversity in thisimportant sequence type. This study highlights thepower of routine WGS by public health agencies to makeepidemiologically significant deductions that would be missed by conventional microbiological methods. Wespeculate that the niche specialisation of sub-Saharan African ST313 lineages is driven in part by the acquisitionof accessory genome elements

Environmental optimality, not heterogeneity, drives regional and local species richness in lichen epiphytes

Aim: We evaluate the scale dependence of species richness–environment relationships with a continent-wide analysis of lichen epiphyte communities. Specifically, our goals are to assess: (1) the dependence of local richness on regional processes, (2) whether species richness is primarily influenced by heterogeneity in environmental conditions or the central tendency of those conditions, and (3) whether the relative influence of these different aspects of the environment differs between local communities and regional species pools. Location: Forests of the contiguous United States. Methods: We used variation partitioning and model averaging of linear models to relate macrolichen richness at 1923 forest inventory plots (c. 4000 m2) to measures of environmental heterogeneity and mean conditions at local and regional scales. Data included 17 local environmental variables and 11 regional-scale variables which were obtained from a national forest inventory, herbarium records and several climate data sources. Results: Regional-scale variables explained more unique variation in local species richness and generally had stronger effects than variables measured locally. However, most variation in local richness was explained jointly by local and regional variables. At both local and regional scales, variables measuring environmental heterogeneity explained little variation in species richness and had weaker effects than variables characterizing mean environmental conditions. Main conclusions: Species richness of epiphytic macrolichens is not regulated by environmental heterogeneity locally or regionally and instead tracks large-scale climate gradients of water availability and temperature. Richness in local communities is influenced by processes operating at both regional and local scales, highlighting the importance of determining large-scale drivers of lichen richness across the North American continent. This research demonstrates a general method for comparing the influence of different aspects of the environment on species richness across scales and should be applicable to many different taxonomic groups