Understanding the impact of altitude and ecological heterogeneity at a fine scale on the populations of malaria vectors is essential to better understand and anticipate eventual epidemiological changes. It could help to evaluate the spread of alleles conferring resistance to insecticides and also determine any increased entomological risk of transmission in highlands due to global warming. We used microsatellite markers to measure the effect of altitude and distance on the population genetic structure of Anopheles funestus and Anopheles gambiae s.s. in the Muheza area in the north-eastern part of Tanzania (seven loci for each species). Our analysis reveals strong gene flow between the different populations of An. funestus from lowland and highland areas, as well as between populations of An. gambiae sampled in the lowland area. These results highlight for An. funestus the absence of a significant spatial subpopulation structuring at small-scale, despite a steep ecological and altitudinal cline. Our findings are important in the understanding of the possible spread of alleles conferring insecticide resistance through mosquito populations. Such information is essential for vector control programmes to avoid the rapid spread and fixation of resistance in mosquito populations.

We present a route for direct growth of boron nitride via a polyborazylene to h-BN conversion process. This two-step growth process ultimately leads to a >25x reduction in the root-mean-square surface roughness of h-BN films when compared to a high temperature growth on Al2O3(0001) and Si(111) substrates. Additionally, the stoichiometry is shown to be highly dependent on the initial polyborazylene deposition temperature. Importantly, chemical vapor deposition (CVD) graphene transferred to direct-grown boron nitride films on Al2O3 at 400 °C results in a >1.5x and >2.5x improvement in mobility compared to CVD graphene transferred to Al2O3 and SiO2 substrates, respectively, which is attributed to the combined reduction of remote charged impurity scattering and surface roughness scattering. Simulation of mobility versus carrier concentration confirms the importance of limiting the introduction of charged impurities in the h-BN film and highlights the importance of these results in producing optimized h-BN substrates for high performance graphene and TMD devices.

Continuously grazed rye grassl clover swards with surface heights of 8 to 10 cm at 5 weeks before a synchronized mating and 7·5 cm at mating were grazed by 151 Greyface ewes stocked at 12 per ha until mating. The effects of two stocking rates (eight and 16 ewes per ha) for 6 weeks over the mating and post-mating period were then studied on live weight, body condition and reproductive peformance. Sward height fell more rapidly post mating when stocked at 16 ewes per ha than at eight ewes per ha, but remained above 3·5 cm until 4 weeks after first mating under both rates. Ewes stocked at 16 per ha became significantly lighter and leaner than ewes stocked at eight per ha. There was no significant effect of post-mating stocking rate on reproductive performance in terms of conception rate and lambing rate to first mating or lambing rate to all matings. Reproductive performance of Greyface ewes is therefore unlikely to be adversely affected by post-mating stocking rate on swards of 7 to 8 cm which do not fall below 3·5 to 4·0 cm until 3 to 4 weeks after mating.

Extended grazing is a management system in which the usual grazing season is lengthened by utilization of hay fields for pasture. Extended grazing systems are a low-input alternative to conventional systems to the extent that they decrease the reliance on inputs such as machinery and energy to harvest forage. Substituting pasturing for harvested forage can therefore potentially decrease production costs and enhance the profitability of livestock production. However, the farm-level economic impacts of such a substitution are not well known. This analysis quantifies these impacts for beef cow/calf production. Specifying alternative meadow management systems for different grasses and using an economic-engineering approach, we have found that extended grazing can be a more profitable option for cow/calf production. Other findings suggest that, in an extended grazing system, the type of meadow, the hay baling method and the associated hay spoilage level also have important effects on production costs and profitability.

There has been considerable research on techniques for artificial insemination of sheep with frozen ram semen (Maxwell, 1984). Acceptable pregnancy rates were reported following ‘two-step’ dilution and freezing of semen in P.V.C. ‘ministraws’ (Colas, 1975; Colas & Guerin, 1981); however, other workers have obtained poor fertility following cervical insemination with semen frozen in straws (Maxwell, etal. 1980; Tervit elal. 1984).

Practical systems for the artificial insemination of sheep have been available for many years (reviewed by Maxwell, 1984). The traditional method is to separate from the flock ewes exhibiting a natural oestrus as identified by ‘teaser’ rams, and inseminate these ewes with freshly collected and diluted semen. The ewes are generally inseminated by suspension of the hindquarters over an elevated rail and deposition of the semen within the first fold of the cervix using a plastic pipette, speculum and headlamp (the cervical insemination method, Salamon, 1976).

A number of methods have been developed for synchronization of oestrus in sheep (reviewed by Maxwell, 1984), but the most successful have been based on the suppression of the oestrous cycle by treatment with a polyurethane progestagenimpregnated intravaginal sponge (Robinson, 1965). A precise synchronization of oestrus and ovulation for artificial insemination (A.I.) is obtained following a 12- to 14-day treatment with the intravaginal sponge and an injection of pregnant mares serum gonadotrophin (PMSG) at sponge removal (Robinson & Smith, 1967). This allows a single fixed time A.I. to be performed on all ewes without the need for detection of oestrus.

One problem encountered in the widespread application of sheep artificial insemination (AI) is the rapid decline in fertility of fresh or liquid chilled ram semen. An effective deep-freezing procedure would enable semen to be collected and stored from selected rams throughout the year for subsequent use in controlled breeding programmes, as well as facilitating the import and export of semen.

Following some encouraging results from the use of pooled semen frozen by an Australian pellet method (Maxwell et al 1980), further field trials were conducted to investigate fertility of semen frozen from individual rams as well as pooled semen. The effects of season of freezing and number of inseminations on fertility were also investigated.

There have been a number of reports on the frozen storage of ram semen, and artificial insemination with frozen semen has been performed on an experimental basis in several countries. Intensive laboratory studies led to considerable progress regarding the freezing and thawing procedures (Salamon & Visser, 1972; Colas, 1975). However, fertility following insemination tends to be considerably lower than for fresh or chilled semen (Maxwell et al. 1980).

This report is concerned with a simple statistical model of the way the brain may function, suggested by the analysis of intelligence test results in two groups of children. The model describes the statistical behaviour of an ideal array of elements, representing the brain, during tests of cognitive ability. Predictions from the model indicate that comparison of the EEC recording taken from groups of children who were good or poor readers would show amplitude differences. These were found between the groups when the eyes were open but not when the eyes were closed–a result explained by the model.

In June, 1962, a type of bug injury was found by the junior author to be prevalent in a well cared for apple orchard of 800 trees at Debec, Carleton County, N.B. Adults of the bug causing the injury were collected in early July and determined by Dr. L. A. Kelton, Entomology Research Institute, Ottawa, as Lygidea mendax Reut., commonly known as the apple redbug. This is the first record of this species in New Brunswick.

Wood (1951) published a list of lepidopterous larvae collected from commercial blueberry fields in Charlotte County. N.B. Among the species consistently collected annually from 1947 to 1952 are the cutworms Spaelotis clandestina (Harr.) and Polia purpurissata (Grt.). Although notes on both species have been given by various authors, including Crumb (1929, 1932), Gibson (1915), and Phipps (19301, no complete account of their life-histories has been published.

In July, 1949, a single specimen of a casebearing coleopterous larva was found feeding on a strawberry leaf in a plantation at the southeastern end of Grand Lake, Queen's County, N.B. During June and July, 1950, about a dozen larvae were found throughdut this area, and a greater number in plantations on both sides of Washademoak Lake, which is southeast and roughly parallel to Grand Lake and about ten miles distant. During 1951 the species was again collected in these areas, and was found in large numbers about 15 miles southeast of Washademoak Lake in the Belleisle watershed. Here the infestation was so great that in one instance 565 larvae were collected with a sweeping net on 100 feet of strawberry row, or an average of five larvae per plant.