The role of regulatory mechanisms for control of plant diseases and food security — case studies from potato production in Britain

Being aware of the potentially devastating impacts of plant diseases on food security, governments have designed and employ plant health legislation to prevent or inhibit the worst impacts. The development of such policies in Britain, and latterly in Europe, can be closely linked to disease events that have occurred in the potato sector. We analyse early and current examples of policies governing potato diseases in Britain to identify the decision processes leading to the implementation of such phytosanitary policies and how they have evolved over time and in response to different disease threats. Reasons for developing and implementing phytosanitary policies include the desire to prevent pathogens being introduced (entering and establishing in a new area), the protection of export markets, and the lack of effective control measures. Circumstances in which regulatory policies would not be appropriate could include situations where a disease is already widely distributed, unacceptable costs, lack of exclusion measures, or difficulties of disease diagnosis. We conclude that in general, government policies have worked well in protecting British potato growing over the last one hundred years, despite of the failures of some of the policies discussed here. They have also contributed much to the development of plant health policies for other crops. Voluntary grower initiatives are a new mechanism complementing existing formal policies with an additional level of security that allows individual growers to take on additional responsibility rather than relying entirely on government legislation

Spectral Properties and Linear Stability of Self-Similar Wave Maps

We study co--rotational wave maps from $(3+1)$--Minkowski space to the three--sphere $S^3$. It is known that there exists a countable family $\{f_n\}$ of self--similar solutions. We investigate their stability under linear perturbations by operator theoretic methods. To this end we study the spectra of the perturbation operators, prove well--posedness of the corresponding linear Cauchy problem and deduce a growth estimate for solutions. Finally, we study perturbations of the limiting solution which is obtained from $f_n$ by letting $n \to \infty$.Comment: Some extensions added to match the published versio

On the roughness of the paths of RBM in a wedge

Reflected Brownian motion (RBM) in a wedge is a 2-dimensional stochastic process Z whose state space in ℝ2 is given in polar coordinates by S = {(r, θ) : r ≥ 0, 0 ≤ θ ≤ ξ } for some 0 α, the strong p-variation of the sample paths of Y is finite on compact intervals, and, for 0 < p ≤ α, the strong p-variation of Y is infinite on [0,T ] whenever Z has been started from the origin. We also show that on excursion intervals of Z away from the origin, (Z,Y ) satisfies the standard Skorokhod problem for X. However, on the entire time horizon (Z,Y ) does not satisfy the standard Skorokhod problem for X, but nevertheless we show that it satisfies the extended Skorkohod problem

Social Determinants of Health: Underreported Heterogeneity in Systematic Reviews of Caregiver Interventions.

BACKGROUND AND OBJECTIVES:Although most people have some experience as caregivers, the nature and context of care are highly variable. Caregiving, socioeconomic factors, and health are all interrelated. For these reasons, caregiver interventions must consider these factors. This review examines the degree to which caregiver intervention research has reported and considered social determinants of health. RESEARCH DESIGN AND METHODS:We examined published systematic reviews and meta-analyses of interventions for older adults with age-related chronic conditions using the PRISMA and AMSTAR 2 checklists. From 2,707 papers meeting search criteria, we identified 197 potentially relevant systematic reviews, and selected 33 for the final analysis. RESULTS:We found scant information on the inclusion of social determinants; the papers lacked specificity regarding race/ethnicity, gender, sexual identity, socioeconomic status, and geographic location. The majority of studies focused on dementia, with other conditions common in later life vastly underrepresented. DISCUSSION AND IMPLICATIONS:Significant gaps in evidence persist, particularly for interventions targeting diverse conditions and populations. To advance health equity and improve the effectiveness of interventions, research should address caregiver heterogeneity and improve assessment, support, and instruction for diverse populations. Research must identify aspects of heterogeneity that matter in intervention design, while recognizing opportunities for common elements and strategies

On the problem of mass-dependence of the two-point function of the real scalar free massive field on the light cone

We investigate the generally assumed inconsistency in light cone quantum field theory that the restriction of a massive, real, scalar, free field to the nullplane $\Sigma=\{x^0+x^3=0\}$ is independent of mass \cite{LKS}, but the restriction of the two-point function depends on it (see, e.g., \cite{NakYam77, Yam97}). We resolve this inconsistency by showing that the two-point function has no canonical restriction to $\Sigma$ in the sense of distribution theory. Only the so-called tame restriction of the two-point function exists which we have introduced in \cite{Ull04sub}. Furthermore, we show that this tame restriction is indeed independent of mass. Hence the inconsistency appears only by the erroneous assumption that the two-point function would have a (canonical) restriction to $\Sigma$.Comment: 10 pages, 2 figure

Sarcoidosis of the hypothalamus and pituitary stalk

We report a rare case of sarcoidosis of the hypothalamic and suprasellar region, with clinical course and the magnetic resonance imaging follow-up

Quantum Graphs II: Some spectral properties of quantum and combinatorial graphs

The paper deals with some spectral properties of (mostly infinite) quantum and combinatorial graphs. Quantum graphs have been intensively studied lately due to their numerous applications to mesoscopic physics, nanotechnology, optics, and other areas. A Schnol type theorem is proven that allows one to detect that a point belongs to the spectrum when a generalized eigenfunction with an subexponential growth integral estimate is available. A theorem on spectral gap opening for ``decorated'' quantum graphs is established (its analog is known for the combinatorial case). It is also shown that if a periodic combinatorial or quantum graph has a point spectrum, it is generated by compactly supported eigenfunctions (``scars'').Comment: 4 eps figures, LATEX file, 21 pages Revised form: a cut-and-paste blooper fixe