We developed a model and subsequently simulated robust white foxtail (Setaria viridis var. robusta-alba Schreiber) or robust purple foxtail (Setaria viridis var. robusta-purpurea Schreiber) growth. SETSIM (SETaria SIMulation) uses the GASP IV simulation language which allows for both continuously changing variables and discrete events. GASP IV provides the necessary integrations and automatic time-stepping essential in simulation. SETSIM uses the materials-flow concept to simulate foxtail growth and development on a population basis. Carbohydrate flow among six compartments (leaf, stem, and root total nonstructural carbohydrate pools; leaf, stem, and root tissue) is governed by nine physiological rates. Each rate is dependent on the physiological state of the foxtail population and the environmental conditions prevailing. Simulation of carbohydrate flow in and out of each compartment results in the net growth of that compartment. By considering all six compartments simultaneously, the vegetative growth and development of a foxtail population can be simulated. Validation of SETSIM with field data recorded over a 2-yr period has shown that this simulator can accurately predict foxtail growth parameters such as dry matter accumulation, plant height, leaf area index, and leaf to stem ratio. SETSIM could serve as a framework for other weed models because of its modular structure. Such models can benefit weed science by predicting the active stage of weed growth, predicting whether a weed could become a problem under different climatic conditions, interfacing with existing crop models to predict yield and harvest restriction, pointing out gaps in our present knowledge in weed biology, and serving as teaching aids.

Soviet plans to divert water from rivers flowing into the Arctic Ocean have led to research into the impact of a reduction in discharge on Arctic sea ice. We consider the mechanisms by which discharge reductions might affect sea-ice cover and then test various hypotheses related to these mechanisms. We find several large areas over which sea-ice concentration correlates significantly with variations in river discharge, supporting two particular hypotheses. The first hypothesis concerns the area where the initial impacts are likely to which is the Kara Sea. Reduced riverflow is associated occur, with decreased sea-ice concentration in October, at the time of ice formation. This is believed to be the result of decreased freshening of the surface layer. The second hypothesis concerns possible effects on the large-scale current system of the Arctic Ocean and, in particular, on the inflow of Atlantic and Pacific water. These effects occur as a result of changes in the strength of northward-flowing gradient currents associated with variations in river discharge. Although it is still not certain that substantial transfers of riverflow will take place, it is concluded that the possibility of significant cryospheric effects and, hence, large-scale climate impact should not be neglected.

Impetigo is common in remote Indigenous children of northern Australia, with the primary driver in this context being Streptococcus pyogenes [or group A Streptococcus (GAS)]. To reduce the high burden of impetigo, the transmission dynamics of GAS must be more clearly elucidated. We performed whole genome sequencing on 31 GAS isolates collected in a single community from children in 11 households with ⩾2 GAS-infected children. We aimed to determine whether transmission was occurring principally within households or across the community. The 31 isolates were represented by nine multilocus sequence types and isolates within each sequence type differed from one another by only 0–3 single nucleotide polymorphisms. There was evidence of extensive transmission both within households and across the community. Our findings suggest that strategies to reduce the burden of impetigo in this setting will need to extend beyond individual households, and incorporate multi-faceted, community-wide approaches.

Non-typhoidal Salmonella is estimated to be the most common bacterial cause of foodborne illness in the United States, causing an estimated one million domestically acquired foodborne illnesses annually. Recent, large outbreaks have highlighted the importance of ground beef as an important source of multidrug-resistant Salmonella. We analysed the epidemiology of salmonellosis outbreaks that were attributed to beef in the United States reported to the Centers for Disease Control and Prevention (CDC) from 1973 to 2011. During 1973–2011, of the 1965 outbreaks of Salmonella where a food vehicle was implicated, 96 were attributed to beef, accounting for 3684 illnesses. We observed a shift in the type of beef implicated in salmonellosis outbreaks, from roast to ground beef. Delicatessen-style roast beef cooked in commercial processing establishments was the predominant type during the 1970s and early 1980s; regulations on cooking and processing essentially eliminated this problem by 1987. Ground beef emerged as an important vehicle in the 2000s; it was implicated in 17 (45%) of the 38 beef-attributed outbreaks reported during 2002–2011. Although this emergence was likely due in part to increased participation in CDC's PulseNet, which was established in 1996, and proactive decisions by the United States Department of Agriculture's Food Safety and Inspection Service, stronger measures are needed to decrease contamination of ground beef with Salmonella.

To identify risk factors for Clostridium difficile infection (CDI) in Danish patients consulting general practice with gastrointestinal symptoms, a prospective matched case-control study was performed; cases (N = 259) had positive cultures for toxigenic C. difficile and controls (N = 455) negative cultures. Data were analysed by conditional logistic regression. In patients aged ⩾2 years (138 cases), hospitalization [odds ratio (OR) 8·4, 95% confidence interval (CI) 3·1–23], consumption of beef (OR 5·5, 95% CI 2·0–15), phenoxymethylpenicillin (OR 15, 95% CI 2·7–82), dicloxacillin (OR 27, 95% CI 3·6–211), and extended spectrum penicillins (OR 9·2, 95% CI 1·9–45) were associated with CDI. In patients aged <2 years none of these were associated with CDI, but in a subgroup analysis contact with animals was associated with CDI (OR 8·1, 95% CI 1·0–64). This study emphasizes narrow-spectrum penicillins, and suggests beef consumption, as risk factors for CDI in adults, and indicates a different epidemiology of CDI in infants.

The combustion synthesis of the common ferroelectric material, BaTiO3, was developed using the stoichiometry: BaO2+0.2 Ti+0.8 TiO2→BaTiO3+0.3 O2. An adiabatic temperature, Tad, of the reaction was calculated from known thermodynamic data to be 1917 °C. Real time chemical changes in the formation of BaTiO3 during the reaction have been monitored using time-resolved X-ray diffraction with synchrotron radiation as the X-ray source. A time resolution of 250 ms was achieved. The combustion synthesis of BaTiO3 was followed by observing the intensities of reactant and product Bragg diffraction peaks in order to qualitatively identify the phases present. Because BaTiO3 forms initially as a cubic phase, X-ray diffraction of the product was monitored for a period of 20 min after the reaction to observe the phase transformation to the tetragonal form. This transformation is evident in these post-reaction scans as the cubic 110 and 220 peaks are split to the tetragonal 101/110 and 202/220 ones, respectively.

The montane cloud-forests of the north-central Andes and the montane grassland and transitional elfin forest of the central Andean páramo contain a high diversity of bird species including several restricted range and uncommon species. Little is known of how densities of Andean cloud-forest species are affected by habitat degradation. Bird densities within pristine and degraded habitats at the Guandera Biological Reserve, Carchi province, Ecuador were recorded over a 10-week period. Densities were calculated for 48 species; where densities could be compared, 69% of species occurred at a higher density in pristine habitats. Pristine forest had the highest species richness with 72 species and páramo contained 44 species. In total, 26% of pristine forest species were only found in pristine forest, 39% of páramo species only in páramo, 13% of farmland species only in farmland and there were no exclusively secondary scrub species; 47% of species found in pristine forest, and 50% found in páramo were found in both secondary scrub and farmland. Restricted range species recorded at Guandera included the Carunculated Caracara Phalcobenus carunculatus, Black-thighed Puffleg Eriocnemis derbyi, Chestnut-bellied Cotinga Doliornis remseni, Crescent-faced Antpitta Grallaricula lineifrons, Masked Mountain-tanager Buthraupis wetmorei and Black-backed Bush-tanager Urothraupis stolzmanni. Three further species that occurred at Guandera of relatively local occurrence were the Grey-breasted Mountain Toucan Andigena hypoglauca, Golden-breasted Puffleg Eriocnemis mosquera and Mountain Avocetbill Opisthoprora euryptera. Of these nine species at least five used degraded habitats, while three occurred only in pristine treeline habitats.

A collaborative exercise, supervised by the World Health Organisation, was set up to compare ELISAs used for the serological detection of Salmonella enteritica serotype Enteritidis in chickens. The aim was to ascertain how far agreement could be reached on the interpretation of optical density readings for high titre, intermediate titre and low titre sera. Two sets of sera were sent to 14 participants. The first set compared high, medium and low titre sera raised in specified-pathogen-free and commercial broiler breeder chickens. The second set comprised 20 sera of different antibody titres raised in commercial birds reared under laboratory conditions and sent blind. Both indirect and double-antibody sandwich blocking ELISAs were used with a number of different detecting antigens. With a few exceptions good agreement was reached on the interpretation of results obtained from high and low titre sera from the optical density obtained with a single serum dilution. Differences were observed in the interpretation of medium titre sera. The results suggested that most ELISAs produce reasonably comparable results and that practical problems may arise from interpretation of the results mainly as a result of the choice of the criteria used for differentiating sera obtained from infected and uninfected chickens. These problems are discussed.

Detectable allelic variation at the Gpi-1 loci on the short arms of the homoeologous group 1 chromsomes in wheat is not common. However, a variant null allele at the Gpi-D1 locus is present in some stocks of Chinese Spring. This has allowed the locus to be mapped between the ω-gliadin locus carried distally on the short arm of chromosome 1D, Gli-D1 (34·5%) and the high-molecular-weight glutenin subunit locus carried near the centromere on the long arm, Glu-D1 (36·2%). The origin of this isoenzyme polymorphism in Chinese Spring stocks is described and its potential significance is discussed in relation to quantitative analysis of aneuploids, alien chromosome addition and substitution lines and intervarietal chromosome substitution lines involving Chinese Spring.

The Funj Sultanate was the most easterly of the chain of Muslim dynastic States which at one time stretched south of the Sahara through Bilād al-Sūdān. Founded early in the sixteenth Christian century (tenth Hijri¯; century) by a king traditionally called ‘Amāra Dūnqas, its centre was on the Blue Nile, around the town of Sennar (Sinnār).

The article considers the origin and validity of statements made by Budge, MacMichael, Crawford and Arkell associating the establishment of Ottoman control over Lower Nubia and the Suakin-Massawa region with Sultan Selim I. These statements are derived from Na‘ūm Shuqayr's Ta'rīkh al-Sūdān, which has two principal relevant passages. In the first, Shuqayr combines, and dates with misleading precision, two traditional anecdotes concerning Nubia, one derived from Burckhardt's Travels in Nubia (1819), the other an aetiological legend of a frontier-fight. The second passage mentions a legendary invasion of Abyssinia by Selim, and relates to a Fūnj (or ‘Abdallābī) claim to Arab ancestry. The personal connexion of Selim I with these exploits is wholly mythical: it is excluded by the detailed account of his acts during 1517 given by the contemporary chronicler, Ibn Iyās. The establishment of Ottoman rule in these two regions was the achievement of Özdemir Pasha in the reign of Süleyman the Magnificent, about the middle of the sixteenth century. The legend of the frontier-fight may refer to an even later episode, in the last quarter of that century.