The Fundamental Multi-Baseline Mode-Mixing Foreground in 21 cm EoR Observations

The primary challenge for experiments measuring the neutral hydrogen power spectrum from the Epoch of Reionization (EoR) are mode-mixing effects where foregrounds from very bright astrophysical sources interact with the instrument to contaminate the EoR signal. In this paper we identify a new type of mode-mixing that occurs when measurements from non-identical baselines are combined for increased power spectrum sensitivity. This multi-baseline effect dominates the mode-mixing power in our simulations and can contaminate the EoR window, an area in Fourier space previously identified to be relatively free of foreground power.Comment: Submitted to Ap

Searching for Dark Photons with Maverick Top Partners

In this paper, we present a model in which an up-type vector-like quark (VLQ) is charged under a new $U(1)_d$ gauge force which kinetically mixes with the SM hypercharge. The gauge boson of the $U(1)_d$ is the dark photon, $\gamma_d$. Traditional searches for VLQs rely on decays into Standard Model electroweak bosons $W,Z$ or Higgs. However, since no evidence for VLQs has been found at the Large Hadron Collider (LHC), it is imperative to search for other novel signatures of VLQs beyond their traditional decays. As we will show, if the dark photon is much less massive than the Standard Model electroweak sector, $M_{\gamma_d}\ll M_Z$, for the large majority of the allowed parameter space the VLQ predominately decays into the dark photon and the dark Higgs that breaks the $U(1)_d$ . That is, this VLQ is a `maverick top partner' with nontraditional decays. One of the appeals of this scenario is that pair production of the VLQ at the LHC occurs through the strong force and the rate is determined by the gauge structure. Hence, the production of the dark photon at the LHC only depends on the strong force and is largely independent of the small kinetic mixing with hypercharge. This scenario provides a robust framework to search for a light dark sector via searches for heavy colored particles at the LHC.Comment: 40 pages and 11 figure

CAADP at 10 - Water is a Missing Link in the Southern African Development Community

Water has a low profile in Comprehensive Africa Agriculture Development Programme (CAADP) processes in the Southern African Development Community (SADC), presenting an opportunity to develop stronger ties between the agriculture and water sectors in the region

Regional stability versus fine-scale changes in community composition of mesotrophic grasslands over 25 years

Ella Morton - wifehttps://stars.library.ucf.edu/cfm-ch-memoranda-1930/1334/thumbnail.jp

Regional stability versus fine-scale changes in community composition of mesotrophic grasslands over 25 years

Long-term studies of vegetation change in grasslands are important to our understanding of the ecology and management of grassland systems, especially for grasslands of high conservation value which have seen a drastic decline due to agricultural intensification and abandonment. This study investigated change over 25 years in 35 mesotrophic grassland sites which were described as species rich at the start of the study period. Some sites had been consistently managed by mowing or grazing whilst others had seen a change to more intensive management or to little or no regular management. Baseline data were available for both quadrat and species list surveys and repeat surveys were undertaken using the same methods on all 35 sites. Multivariate analysis using non metric multidimensional scaling revealed that the overall community composition was similar in the original and repeat surveys but some differences were revealed when the sites were categorised by management type. The two survey methods provided different information about both the principal vegetation communities and about other aspects of the site including the presence of rare species. There were losses and gains of species of importance to conservation with more losses than gains overall and there was some evidence for species losses at sites which had been managed consistently for conservation. These changes may be linked to aspects of the management regime, isolation of sites or changes in soil fertility levels but a greater understanding of the local and regional processes affecting diversity in mesotrophic grasslands is required to inform conservation management

Family Resources Survey: United Kingdom 2010/11

The Family Resources Survey collects information on the incomes and circumstances of private households in the United Kingdom. It has been running since October 1992. This report summarises the results for the 2010/11 full survey year in which approximately 25,000 households were interviewed. The report is divided into sections covering: Income and State Support Receipt; Tenure; Savings and Investments; Disability; Carers; Occupation and Employment; and Pension Participation

Genetic diversity and connectivity in fragmented populations of Rhinanthus minor in two regions with contrasting land-use

Knowledge of genetic diversity and connectivity within and between populations of specialist meadow plants is crucial to developing effective conservation strategies at the landscape-scale. This study investigated levels of genetic diversity within, and gene flow between populations of a key annual species, Rhinanthus minor in protected meadows and landscape matrix sites in two contrasting regions. Possible barriers to gene flow were also analysed. Leaf material from 714 individuals in an extensively managed upland region and an intensively managed lowland region of the UK was genotyped using microsatellite markers. Genetic diversity was similar in the two regions (He = 0.48 and 0.44). FST values indicated population differentiation in both regions but the estimate was higher in the lowland (FST = 0.28) than in the upland region (FST = 0.19); evidence of global structure was revealed in a spatial principal components analysis but a maximum likelihood population effects model did not identify significant predictors of population differentiation after testing the effects of Euclidean geographic distance, land cover and elevation. Conservation strategies should aim to maintain large populations in meadows to enhance genetic diversity. At the same time the focus should be on existing and additional species-rich grassland fragments, particularly in areas of intensive land-use, if genetic connectivity is to be retained.</p

Using electronic health records to support clinical trials: a report on stakeholder engagement for EHR4CR

Background. The conduct of clinical trials is increasingly challenging due to greater complexity and governance requirements as well as difficulties with recruitment and retention. Electronic Health Records for Clinical Research (EHR4CR) aims at improving the conduct of trials by using existing routinely collected data, but little is known about stakeholder views on data availability, information governance, and acceptable working practices. Methods. Senior figures in healthcare organisations across Europe were provided with a description of the project and structured interviews were subsequently conducted to elicit their views. Results. 37 structured interviewees in Germany, UK, Switzerland, and France indicated strong support for the proposed EHR4CR platform. All interviewees reported that using the platform for assessing feasibility would enhance the conduct of clinical trials and the majority also felt it would reduce workloads. Interviewees felt the platform could enhance trial recruitment and adverse event reporting but also felt it could raise either ethical or information governance concerns in their country. Conclusions. There was clear support for EHR4CR and a belief that it could reduce workloads and improve the conduct and quality of trials. However data security, privacy, and information governance issues would need to be carefully managed in the development of the platform