This paper describes the early stages in the development and testing of a spatio-temporal rule-based model of snow transport by wind over complex terrain. The model uses a cell-based approach and takes into account a range of meteorological, snow-pack and topographic variables. Simple rules are used to determine movement of material from cell-to-cell within the model.

A geographic information system is utilized in modelling wind vectors and the influence of topography upon those vectors, and creating the resulting pattern of snow accumulation at a resolution of 50 m. These patterns of accumulation have been compared with empirical work in the field and, although field data were limited, a good qualitative correlation has been found; for example, modelled accumulations correlate with known areas of accumulation such as gullies and hollows.

Human salmonellosis linked to contact with live poultry is an increasing public health concern. In 2012, eight unrelated outbreaks of human salmonellosis linked to live poultry contact resulted in 517 illnesses. In July 2012, PulseNet, a national molecular surveillance network, reported a multistate cluster of a rare strain of Salmonella Braenderup infections which we investigated. We defined a case as infection with the outbreak strain, determined by pulsed-field gel electrophoresis, with illness onset from 25 July 2012–27 February 2013. Ill persons and mail-order hatchery (MOH) owners were interviewed using standardized questionnaires. Traceback and environmental investigations were conducted. We identified 48 cases in 24 states. Twenty-six (81%) of 32 ill persons reported live poultry contact in the week before illness; case-patients named 12 different MOHs from eight states. The investigation identified hatchery D as the ultimate poultry source. Sampling at hatchery D yielded the outbreak strain. Hatchery D improved sanitation procedures and pest control; subsequent sampling failed to yield Salmonella. This outbreak highlights the interconnectedness of humans, animals, and the environment and the importance of industry knowledge and involvement in solving complex outbreaks. Preventing these infections requires a ‘One Health’ approach that leverages expertise in human, animal, and environmental health.

Significant new opportunities for astrophysics and cosmology have been identified at low radio frequencies. The Murchison Widefield Array is the first telescope in the southern hemisphere designed specifically to explore the low-frequency astronomical sky between 80 and 300 MHz with arcminute angular resolution and high survey efficiency. The telescope will enable new advances along four key science themes, including searching for redshifted 21-cm emission from the EoR in the early Universe; Galactic and extragalactic all-sky southern hemisphere surveys; time-domain astrophysics; and solar, heliospheric, and ionospheric science and space weather. The Murchison Widefield Array is located in Western Australia at the site of the planned Square Kilometre Array (SKA) low-band telescope and is the only low-frequency SKA precursor facility. In this paper, we review the performance properties of the Murchison Widefield Array and describe its primary scientific objectives.

In November 2009, we initiated a multistate investigation of Salmonella Montevideo infections with pulsed-field gel electrophoresis pattern JIXX01.0011. We identified 272 cases in 44 states with illness onset dates ranging from 1 July 2009 to 14 April 2010. To help generate hypotheses, warehouse store membership card information was collected to identify products consumed by cases. These records identified 19 ill persons who purchased company A salami products before onset of illness. A case-control study was conducted. Ready-to-eat salami consumption was significantly associated with illness (matched odds ratio 8·5, 95% confidence interval 2·1–75·9). The outbreak strain was isolated from company A salami products from an environmental sample from one manufacturing plant, and sealed containers of black and red pepper at the facility. This outbreak illustrates the importance of using membership card information to assist in identifying suspect vehicles, the potential for spices to contaminate ready-to-eat products, and preventing raw ingredient contamination of these products.

Multiple salmonellosis outbreaks have been linked to contaminated tomatoes. We investigated a multistate outbreak of Salmonella Typhimurium infections among 190 cases. For hypothesis generation, review of patients' food histories from four restaurant-associated clusters in four states revealed that large tomatoes were the only common food consumed by patients. Two case-control studies were conducted to identify food exposures associated with infections. In a study conducted in nine states illness was significantly associated with eating raw, large, round tomatoes in a restaurant [matched odds ratio (mOR) 3·1, 95% confidence interval (CI) 1·3–7·3]. In a Minnesota study, illness was associated with tomatoes eaten at a restaurant (OR 6·3, mid-P 95% CI 1·05–50·4, P=0·046). State, local and federal regulatory officials traced the source of tomatoes to Ohio tomato fields, a growing area not previously identified in past tomato-associated outbreaks. Because tomatoes are commonly eaten raw, prevention of tomato contamination should include interventions on the farm, during packing, and at restaurants.

There is increasing evidence that pathogens can play a significant role in species decline. This study of a complete free-living species reveals a cost of blood parasitism to an endangered host, the Pink Pigeon Columba mayeri, endemic to Mauritius. We investigated the prevalence and effect of infection of the blood parasite, Leucocytozoon marchouxi, in the free-living Pink Pigeon population. Overall, L. marchouxi infection prevalence detected was 18·3%. Juveniles were more likely to be infected than older birds and there was geographical variation in infection prevalence. Survival of birds infected with L. marchouxi was lower than that of uninfected birds to 90 days post-sampling. This study suggests that while common haematozoa are well tolerated in healthy adults, these parasites may have greater pathogenic potential in susceptible juveniles. The study is unusual given its completeness of species sampling (96%) within a short time-period, the accurate host age data, and its focus on blood parasites in a threatened bird species. Species for which long-term life-history data are available for every individual serve as valuable models for dissecting the contribution of particular pathogens to species decline.

Data were collected on 6578 patients diagnosed with AIDS at 52 clinical centres in 17 European countries during an 11-year period from 1979 to 1989. The centres were divided into four regions, North, Central, Southeast, and Southwest. Differences in the incidence of most AIDS-defining opportunistic infections and malignancies were found. After adjusting for known possible confounders, statistically significant differences between regions remained. Pneumocystis carinii pneumonia (PCP) was more common in Northern Europe, Kaposi's sarcoma and toxoplasmosis in Central Europe, cytomegalovirus retinitis in South-eastern Europe, and extrapulmonary tuberculosis in South-western Europe. These differences we attribute primarily to different degrees of exposure to the respective underlying pathogens. The prevalence of these and other micro-organisms will determine the clinical course of HIV infections in parts of Eastern Europe and elsewhere where the virus now is spreading.

A genetic polymorphism is responsible for determining that some humans express lactase at high levels throughout their lives and are thus lactose tolerant, while others lose lactase expression during childhood and are lactose intolerant. We have previously shown that this polymorphism is controlled by an element or elements which act in cis to the lactase gene. We have also reported that 7 polymorphisms in the lactase gene are highly associated and lead to only 3 common haplotypes (A, B and C) in individuals of European extraction. Here we report the frequencies of these polymorphisms in Caucasians from north and south Europe and also from the Indian sub-continent, and show that the alleles differ in frequency, the B and C haplotypes being much more common in southern Europe and India. Allelic association studies with lactase persistence and non-persistence phenotypes show suggestive evidence of association of lactase persistence with certain alleles. This association was rather more clear in the analysis of small families, where haplotypes could be determined. Furthermore haplotype and RNA transcript analysis of 11 unrelated lactase persistent individuals shows that the persistence (highly expressed) allele is almost always on the A haplotype background. Non-persistence is found on a variety of haplotypes including A. Thus it appears that lactase persistence arose more recently than the DNA marker polymorphisms used here to define the main Caucasian haplotypes, possibly as a single mutation on the A haplotype background. The high frequency of the A haplotype in northern Europeans is consistent with the high frequency of lactase persistence.

New geological field mapping along a 24-km-long portion of the Mere Fault, in the northern part of the Wessex Basin, together with seismic reflection and other subsurface data, allow an analysis of displacement, both along the length and down the dip of the reactivated fault. The principal segments of the Mere Fault dip south at about 70° and display components of both syndepositional normal displacement and later reversal of movement during basin contraction. Minimum estimates of the largest down-to-the-south displacements range from less than 100 m at the surface to 350 m at the top of the pre-Permian basement and these values decrease to zero toward the fault segment tips. Estimates that allow for reverse movement along the fault suggest that there must have been at least 500 m of normal displacement along the central portion of the segment. Stratigraphical separation at the surface indicates that the largest down-to-the-north displacements, associated with later fault reversal, are at least 200 m and occur in the east, where reversal of movement has taken place on an early, high-angle fault segment. In the west, the principal fault strands are eroded to deeper stratigraphical levels where largely normal slip is preserved and segments are linked by normal and oblique transfer faults. The Wardour Monocline was developed during basin contraction, in part by movement along a concealed fault segment, overstepping from the Mere Fault at the surface, and in part over a relay ramp between the two fault segments.

Carcinoid tumour is one of the rarest middle-ear neoplasms. We describe here a case of carcinoid tumour of the middle-ear cleft that presented with aural as well as systemic symptoms. Diagnostic difficulty was encountered using light microscopy, but electron microscopy revealed the neurosecretory granules.

Extreme value problems and particularly those arising in the combinatorial field have a peculiar interest and challenge in that an exact solution is rarely possible. We discuss here four combinatorial extreme value problems each concerned with the distribution of the largest (or smallest) of a set of mutually dependent variables. These problems, widely different in character possess three points in common. First the probability distribution functions of the variables considered cannot be obtained explicitly, nor secondly can the moments of the variable, and thirdly the probability distribution functions are difficult to evaluate even for moderate sized samples. We shall treat the situation where the variables, or functions of them, have probability distribution functions which tend to an exponential limit, analogous to the well-known limit for extreme values in the case of independent events. The p.d.f.'s for the upper tails of the distributions which we consider are found to be very closely contained within a pair of inequalities (Bonferroni Inequalities), especially in the regions of statistical significance.

The analysis of the intervals which arise between events occurring randomly in time is a problem which is both interesting and important statistically. Two distinct types of data may arise: either the period of time during which the events are observed may be fixed or the number of intervals may be fixed. It may happen that the intervals between pairs of events, close in time, cannot be accurately measured. It is thus necessary to consider the lengths of intervals ordered according to their magnitudes. We derive here functions of these ordered interval lengths which may be used as a basis for tests for randomness of events occurring in a fixed period of time. The mathematical formulation of this problem is in terms of the classical problem of intervals between points on a line.