Invited review: Treatment of cows with an extended postpartum anestrous interval

Cows with an extended interval from calving to first ovulation (PPI) have increased intervals from calving to conception and are more likely to be culled compared with cows with a short PPI. In year-round calving dairy herds, between 11 and 38% of cows are reported as anestrus by 50 or 60 d after calving. In seasonally calving dairy herds, between 13 and 48% of cows are diagnosed as anovulatory anestrus at the start of the breeding period. Ovulation and estrus after calving are delayed when the positive feedback effects of estradiol on release of LH from the pituitary, and circulating concentrations of metabolic hormones such as insulin and insulin-like growth factor-I, are reduced by a variety of environmental factors. The main factors are limited energy intake, lower body reserves, increased partitioning of energy to milk production, suckling, and peripartum disease. Treatment options for cows with an extended PPI include hormonal and management strategies. Hormonal treatments that include a period of progesterone supplementation result in the majority of treated animals displaying estrus with a subsequent luteal phase of normal duration and improved pregnancy rates compared with untreated controls. Hormonal interventions also tend to have more predictable outcomes compared with management changes, such as manipulating body condition or dietary intakes after calving, and usually have some estrous synchronization effect, thus facilitating the use of artificial insemination. However, responses to any treatment are variable and are related to those factors that influence duration of the PPI, such as body condition and parity.     

Passive microwave emission from smooth bare soils: Developing a simple model to predict near surface water content

MICRO-SWEAT is a coupled microwave emission and soilvegetation-atmosphere transfer scheme. It can predict, among other things, the L band (21 cm wavelength) microwave brightness temperature ( T B ) for a smooth bare soil from knowledge of the soil hydraulic properties and local meteorological data. T B is the product of the apparent emissivity ( e app ) and the effective physical temperature of the soil profile ( T eff ). The modelled relationship between e app and average 0-2 cm soil water content was used to develop a simple semi-empirical model, which predicts the near surface water content from knowledge of the particle size distribution and e app . T eff was found to be comparable to the soil temperature at 11 cm depth, and was estimated using a simple sinusoidal function based on thermal diffusivity to extrapolate the temperature at 11 cm depth from knowledge of the diurnal variation in air temperature. The dependence of T B on incidence angle was predicted by MICRO-SWEAT and also incorporated. This simple model was then successfully used to predict the 0-2 cm water content from knowledge of T B, the air temperature regime and the particle size distribution, for data collected at various look angles over three different soils using a truck-based radiometer.     

Adrenergic receptors and secretory responses of the rat submandibular salivary gland after periodic incisor reduction

While loss-of-function mutations in Gsalpha are invariably associated with the short stature and brachydactyly of Albright hereditary osteodystrophy (AHO), the association with hormone resistance (to parathyroid hormone and thyrotropin) typical of pseudohypoparathyroidism type Ia (PHP-Ia) is much more variable. Observational studies and DNA polymorphism analysis suggest that maternal transmission of the Gsalpha mutation may be required for full expression of clinical hormone resistance. To test this hypothesis, we studied transmission of a frameshift mutation in Gsalpha through three generations of a pedigree affected by AHO and PHP-Ia. While all family members carrying this loss-of-function mutation in one Gsalpha allele had AHO, neither the presence of the mutation nor the degree of reduction of erythrocyte Gsalpha bioactivity allowed prediction of phenotype (AHO alone versus AHO and PHP-Ia). Paternal transmission of the mutation (from the patriarch of the first generation to three members of the second generation) was not associated with concurrent PHP-Ia, but maternal transmission (from two women in the second generation to four children in the third generation) was invariably associated with PHP-Ia. No expansion of an upstream short CCG nucleotide repeat region was detected, nor was there evidence of uniparental disomy by polymorphism analysis. This report, the first to document the effects across three generations of both paternal and maternal transmission of a specific Gsalpha mutation, strongly supports the hypothesis that a maternal factor determines full expression of Gsalpha dysfunction as PHP-Ia.     

A survey of platinum hydrous oxide electrochemistry at elevated temperature: evidence for a new component in the β-deposit

Hydrous (or ) oxide. films produced on platinum in acid at room temperature usually give rise to two reduction peaks, in addition to the monolayer oxide response, on a negative sweep extending to about 0V. This has been attributed to the presence of two hydrous oxide components (designated as HO1 and HO2) in the film. It was confirmed in the present work that under more severe conditions, 3.0 m H₂SO₄ at 60°C, an additional, quite significant, peak — apparently due to the presence of a further hydrous oxide component (HO3) — may be observed. The approximate peak maximum potential values (RHE scale) were 0.4 V (HO1), 0.2 V (HO2) and 0.0 V (HO3); the E _p values are given here only as a guide: the processes involved occur under very irreversible conditions and the values vary with factors such as sweep rate, film thickness, temperature, etc. The differences in behaviour between these components is assumed to be due to factors such as the degree of aggregation and compactness in different regions of the gel-type, amorphous deposit. A brief account is given of the increasing evidence from different laboratories of unusual responses for platinum electrodes in aqueous acid solution.