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The growing trend of solar photovoltaic (PV) adoption has motivated homeowners and independent solar PV plants to assume the role of electricity generators. Utility companies need to address the changes in supply and demand to formulate effective distribution plans. Monitoring the power output of the photovoltaic array is a key task in ensuring the correct estimation of the electricity production of the system. Nevertheless, the literature recognizes the obstacle that expensive on-site monitoring sensors have on the cost of small-scale and medium-scale PV applications. Mathematical models based on the estimation of power output from historical data are the most used techniques to address the need for expensive monitoring systems. Estimating the power output of a PV array depends on the cell temperature, ambient temperature, and solar irradiance. This paper proposes a machine learning model to forecast site-specific ambient temperature and solar irradiance. The results contribute to the generation of low-cost data-driven models to save money by eliminating the need to install on-site sensors. The methodology employed off-site publicly-available weather data from neighboring weather stations as an alternative to on-site measurements. A 5-layer deep neural network was trained using 5 years’ worth of historical data from a remote weather station in Green Bay, WI, to predict on-site parameters for a solar array located about 45 miles away in Keshena, WI. The model was found to be suitable for site-specific ambient temperature prediction. The ozone Dobson was a key parameter for solar irradiance prediction, given that the predictive accuracy of the proposed model was limited by the size of the training data.

The major histocompatibility complex region has been implicated in explaining some of the variation observed in adaptability and tick susceptibility of cattle. The bovine leukocyte antigen region of 192 cattle representing indigenous, composite and exotic breeds used in commercial beef production in Namibia and South Africa was investigated using four microsatellite markers. Ticks counted under the tail were taken as an indicator of tick susceptibility. Tick scores of all but one population was low (11 to 20 ticks), with only the South African Bonsmara population having an average score of 31 to 40 ticks per animal. The observed variation based on four microsatellite markers ranged from 5.5 alleles in Namibian Afrikaner to 7.7 alleles in South African Nguni and Bonsmara cattle. Unbiased heterozygosity values ranged from 0.66 (Namibian Afrikaner) to 0.76 (South African Bonsmara). Structure analyses grouped the five populations into three indistinct clusters with limited genetic variation between the populations.

The most popular beef breed in South Africa is the Bonsmara, a locally developed composite breed adapted to sub-tropical conditions. The establishment of a genomic reference population is currently ongoing for the application of genomic selection. To date, 583 Bonsmara cattle (388 bulls and 195 cows) have been genotyped with the GeneSeek®Genomic Profiler Bovine HD™ Chip (GGP-HD) 80 K chip, and the population structure of the reference population was studied. The average minor allele frequency for the Bonsmara was 0.280 across 56 248 autosomal single-nucleotide polymorphisms (SNPs), whereas the observed and expected heterozygosity values were 0.361 and 0.365, respectively. After pruning the data set for SNPs in linkage disequilibrium, 19 119 SNPs were retained, averaging 659 SNPs per autosomal chromosome. This generated an average SNP density of 1 SNP per 90 kb. Structure analysis revealed a non-homogenous population with a high level of genetic admixture, which may negatively influence genomic breeding value prediction accuracy. Genotyping of a further 990 Bonsmara cattle are pending, using the GeneSeek®GGP-HD 150 K chip. As more animals will be added to the reference population, the profile of the reference population are expected to change in such a way to ensure improved genomic estimated breeding value accuracies.

The functional properties of enzymically dispersed mast cells from human lung parenchyma, colonic mucosa and colonic submucosa/muscle were compared. In general, the cells responded in a similar fashion to the histamine releasing action of a variety of immunological and non-immunological stimuli. However, some differences were observed in their responses to anti-allergic compounds. In total, these data indicate that there are subtle variations between human colonic and pulmonary mast cells but that these differences are much less sharply defined than in the rodent.

A teaching project dealing with an experimental introduction to the concept of density, planned for science courses at the lower secondary school level, is described. A group of teachers was introduced with the project during a training course; in the following year they adopted it in their classes (6th, 7th, 8th grades), for a total of 389 pupils.The approach followed in the project is based on presenting the pupils with a range of solid objects (rods, balls, blocks) made in different sizes and materials. These are weighed and their volumes measured by dipping them into a graduated vessel and reading the rise of water level. Graphs of mass versus volume for objects of the same material are found to be linear, with the slope of each plot being a characteristic of a particular material, viz. its density.

A brief review is given of the copper-based casting alloys, suitable for the manufacture of ship’s propellers. Some specific properties of these alloys are illustrated. The moulding, melting and casting techniques employed in the production of high-quality propellers must satisfy stringent requirements and a well-considered practical application of a thorough theoretical knowledge of the solidification process is necessary. Attention is called to the cavitation-erosion-corrosion resistance of the copper-based propeller alloys. Some basic factors relating to the Smith diagram are put forward. Finally, some important indications are given concerning propeller repair.

An extract has been prepared from the suprarenal cortex, which, when injected into rabbits, lowers the blood calcium to the extent of about 30 per cent. ; the maximum fall occurs after 24 hours, and returns to normal in about 48 hours. The extract prepared from the suprarenal cortex resembles that obtained from ovary and corpus luteum, both in physical characteristics, and in the production of a typical response on the part of the blood calcium. It would appear that the hormone of the suprarenal cortex that is capable of lowering the blood calcium is very similar and possibly identical with the hormone of the ovary, having the same function. A definite relationship has been established between the suprarenal cortex and the ovary, justifying the long-suspected connection between the two glands.

It has long been recognised that the testis has an influence upon growth in general, and especially upon the growth of bone. This was the basis for the generalisation formulated by the early observers that growth and reproduction are essentially opposed to one another. Later investigations indicated, however, that the changes produced by castration are not due to the abolishing of spermatogenesis but to the fact that the normal internal secretion of the testis is not available for controlling the growth of bone.

The largest beef breed in South Africa is the Bonsmara, a locally developed composite breed, consisting of approximately 81,000 registered cows. The Bonsmara was developed specifically for adaptability to sub-tropical conditions, using objective measurements between 1937 and 1963, and as a breed is subjected to mandatory performance recording. Biological samples have also been stored for the last 10 yr. The Bonsmara is therefore well placed to engage in genomic selection and is in the process of compiling a genomic reference population. To date, 583 Bonsmara cattle (388 bulls and 195 cows) were genotyped with the GeneSeek Genomic Profiler Bovine HD Chip (GGP-HD) 80K chip (Neogen, Lincoln, NE, USA) and the results of another approximately 990 Bonsmara cattle are pending, using the GeneSeek GGP-HD 150K chip. In this preliminary study, the genotypes of the initial 583 Bonsmara cattle were characterized for genome-wide linkage disequilibrium, as this may affect the accuracy of genomic estimated breeding values (GEBV). We used 56,248 autosomal SNPs to determine extent of LD in the current reference population. The software package PLINK was used in the analysis and the squared correlation of the alleles at 2 loci (r2) was used as a measure of LD. A 50 SNP sliding window was used with a 5 SNP increment between windows. Analysis of the marker pairs found that the level of LD in the current reference population decreased with physical distance between SNPs. Overall, the mean r2was 0.405. Genomic regions smaller than 420 kb and 815 kb displayed strong LD (r2> 0.8) and useful LD (r2> 0.2), respectively. These preliminary results indicate that some population stratification may be present in the reference population and should be taken into consideration during the estimation of GEBVs.