Stronger Partnerships for Safer Food: An Agenda for Strengthening State and Local Roles in the Nation's Food Safety System

Examines federal, state, and local agencies' responsibilities, strengths, and weaknesses in ensuring food safety. Recommends systemwide reforms to enhance state and local roles and improve surveillance, outbreak response, and regulation and inspection

On the validity and breakdown of the Onsager symmetry in mesoscopic conductors interacting with environments

We investigate magnetic-field asymmetries in the linear transport of a mesoscopic conductor interacting with its environment. Interestingly, we find that the interaction between the two systems causes an asymmetry only when the environment is out of equilibrium. We elucidate our general result with the help of a quantum dot capacitively coupled to a quantum Hall conductor and discuss the asymmetry dependence on the environment bias and induced dephasing.Comment: 4 pages, 4 figures; discussions clarified; published versio

Exotic matter on singular divisors in F-theory

We analyze exotic matter representations that arise on singular seven-brane configurations in F-theory. We develop a general framework for analyzing such representations, and work out explicit descriptions for models with matter in the 2-index and 3-index symmetric representations of SU($N$) and SU(2) respectively, associated with double and triple point singularities in the seven-brane locus. These matter representations are associated with Weierstrass models whose discriminants vanish to high order thanks to nontrivial cancellations possible only in the presence of a non-UFD algebraic structure. This structure can be described using the normalization of the ring of intrinsic local functions on a singular divisor. We consider the connection between geometric constraints on singular curves and corresponding constraints on the low-energy spectrum of 6D theories, identifying some new examples of apparent "swampland" theories that cannot be realized in F-theory but have no apparent low-energy inconsistency.Comment: 71 page

Concerted hydrogen atom exchange between three HF molecules

We have investigated the termolecular reaction involving concerted hydrogen exchange between three HF molecules, with particular emphasis on the effects of correlation at the various stationary points along the reaction. Using an extended basis, we have located the geometries of the stable hydrogen-bonded trimer, which is of C(sub 3h) symmetry, and the transition state for hydrogen exchange, which is of D(sub 3h) symmetry. The energies of the exchange reation were then evaluated at the correlated level, using a large atomic natural orbital basis and correlating all valence electrons. Several correlation treatments were used, namely, configration interaction with single and double excitations, coupled-pair functional, and coupled-cluster methods. We are thus able to measure the effect of accounting for size-extensivity. Zero-point corrections to the correlated level energetics were determined using analytic second derivative techniques at the SCF level. Our best calculations, which include the effects of connected triple excitations in the coupled-cluster procedure, indicate that the trimer is bound by 9 +/- 1 kcal/mol relative to three separate monomers, in excellent agreement with previous estimates. The barrier to concerted hydrogen exchange is 15 kcal/mol above the trimer, or only 4.7 kcal/mol above three separated monomers. Thus the barrier to hydrogen exchange between HF molecules via this termolecular process is very low

Non-Higgsable clusters for 4D F-theory models

We analyze non-Higgsable clusters of gauge groups and matter that can arise at the level of geometry in 4D F-theory models. Non-Higgsable clusters seem to be generic features of F-theory compactifications, and give rise naturally to structures that include the nonabelian part of the standard model gauge group and certain specific types of potential dark matter candidates. In particular, there are nine distinct single nonabelian gauge group factors, and only five distinct products of two nonabelian gauge group factors with matter, including $SU(3) \times SU(2)$, that can be realized through 4D non-Higgsable clusters. There are also more complicated configurations involving more than two gauge factors; in particular, the collection of gauge group factors with jointly charged matter can exhibit branchings, loops, and long linear chains.Comment: 35 pages, 3 figures; v2: references added; v3: constraints on two-factor product groups tightened, minor other corrections; v4: references added, some issues clarified in discussion of potential physical relevanc

ECONOMIC FEASIBILITY OF THE CATTLE FEEDING INDUSTRY IN THE NORTHERN PLAINS AND WESTERN LAKES STATES - SUMMARY

The five-state study area of the Northern Plains and Western Lakes States, Minnesota, Montana, North Dakota, South Dakota, and Wisconsin, has adequate feed supplies and feeder cattle to markedly increase cattle feeding. Feed costs in these states have historically been lower than in the Southern Plains States. However, higher transportation costs appear to offset that advantage. Close access to slaughter plants in these states could offset that transportation disadvantage. Backgrounding of cattle appears to be quite profitable and cattle feeding, especially in larger sized feedlots, can be profitable. However, the cattle feeding industry has an increasing level of excess capacity. To be successful, new feedlots in the Northern Plains and Western Lakes States would need cost efficiencies to offset higher production costs, compared to Nebraska and Kansas, or would need to produce for a niche market unaffected by the lower operating costs of already established feedlots in the Central and Southern Plains States. Finally, a range of strategies are available in developing value-added cattle production in the Northern Plains and Western Lakes States. These strategies embody differing levels of capital investment, and involve different levels of risk and profitability.cattle feeding, Northern Plains, economies of scale, cooperative ownership, entrance strategies, Production Economics,

Fidelity in complex behaviour change interventions : a standardised approach to evaluate intervention integrity

Objectives: The aim of this study was to (1) demonstrate the development and testing of tools and procedures designed to monitor and assess the integrity of a complex intervention for chronic pain (COping with persistent Pain, Effectiveness Research into Self-management (COPERS) course); and (2) make recommendations based on our experiences. Design: Fidelity assessment of a two-arm randomised controlled trial intervention, assessing the adherence and competence of the facilitators delivering the intervention. Setting: The intervention was delivered in the community in two centres in the UK: one inner city and one a mix of rural and urban locations. Participants: 403 people with chronic musculoskeletal pain were enrolled in the intervention arm and 300 attended the self-management course. Thirty lay and healthcare professionals were trained and 24 delivered the courses (2 per course). We ran 31 courses for up to 16 people per course and all were audio recorded. Interventions: The course was run over three and a half days; facilitators delivered a semistructured manualised course. Outcomes: We designed three measures to evaluate fidelity assessing adherence to the manual, competence and overall impression. Results: We evaluated a random sample of four components from each course (n=122). The evaluation forms were reliable and had good face validity. There were high levels of adherence in the delivery: overall adherence was two (maximum 2, IQR 1.67–2.00), facilitator competence exhibited more variability, and overall competence was 1.5 (maximum 2, IQR 1.25–2.00). Overall impression was three (maximum 4, IQR 2.00–3.00). Conclusions: Monitoring and assessing adherence and competence at the point of intervention delivery can be realised most efficiently by embedding the principles of fidelity measurement within the design stage of complex interventions and the training and assessment of those delivering the intervention. More work is necessary to ensure that more robust systems of fidelity evaluation accompany the growth of complex interventions