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.     

Monolithic capillary electrophoresis device with integrated fluorescence detector

A monolithic capillary electrophoresis system with integrated on-chip fluorescence detector has been microfabricated on a silicon substrate. Photodiodes in the silicon substrate measure fluorescence emitted from eluting molecules. The device incorporates an on-chip thin-film interference filter that prevents excitation light from inhibiting the fluorescence detection. A transparent AZO conducting ground plane is also used to prevent the high electric fields used for the separation from interfering with the photodiode response. Separations of DNA restriction fragments have been performed in these devices with femtogram detection limits using SYBR Green I intercalating dye.     

Formaldehyde in human cancer cells: detection by preconcentration-chemical ionization mass spectrometry

A rapid and highly sensitive method for the detection of formaldehyde utilizing selected ion flow tube-chemical ionization mass spectrometry is reported. Formaldehyde in aqueous biological samples is preconcentrated by distillation and directly analyzed using gas-phase thermal energy proton transfer from H30+; this procedure can be performed in 30 min. The method detection limit for formaldehyde based on seven replicate measurements of reference water samples (2.5 mL) is 80 nM at the 99% confidence level. Detection is linear up to 130 microM. This technique allows the first measurement of natural formaldehyde levels in human cancer cells in vitro. Elevated levels of formaldehyde relative to the reference water are observed for doxorubicin-sensitive cells (MCF-7 breast cancer, K562 leukemia, HeLa S3 cervical cancer) with estimated intracellular formaldehyde concentrations ranging from 1.5 to 4.0 microM, whereas formaldehyde in doxorubicin-resistant MCF-7/Adr breast cancer cells is essentially at reference level. This trend is inverted for prostate cancer cells LNCaP (sensitive) and DU-145 (resistant). Correlation of natural formaldehyde level with doxorubicin cytotoxicity is a function of the expression of enzymes that neutralize oxidative stress and the drug efflux pump, P-170 glycoprotein.     

Developing a framework for sustainability management in engineering SMEs

Sustainability issues in manufacturing and production are growing exponentially. Initially referring to environmental considerations, sustainability now also encompasses social, ethical and economical responsibilities. This paper focuses on engineering and manufacturing SMEs and outlines a regional study undertaken on a small number of these companies which have succeeded in developing appropriate tools and strategies to satisfy the current ISO 14001 standard. Their experiences, strategies and solutions are used to devise and develop a framework for sustainability management, taking an incremental approach in moving from environmental management, using ISO 14001 as a foundation, to sustainability management which will contribute to an annual sustainability report which is currently only undertaken by large corporations. The framework consists of two levels, with the first focusing on ISO 14001 and the second aimed towards managing all social, environmental and economical aspects within an engineering SME. Key results from the regional study of ISO 14001 certified engineering SMEs highlight the importance of environmental and sustainability awareness programs for top management, eliciting and obtaining their full support and commitment.     

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.     

Profile Scaling of Miniature Centrifugal Fans

This paper addresses issues that relate to downscaling the height of centrifugal fans for application in low profile technologies, such as the cooling of portable power electronics. The parameters studied include flow rate, pressure rise, and power consumption characteristics. The former two of these are measured using a fan characterization rig and the latter by directly measuring the power supplied to the fan. These are studied for fan diameters ranging from 15 to 30 mm with numerous profile heights between 0.3 mm and 15 mm. It is found that all of the phenomena encountered are best described in terms of fan aspect ratio. The results show that the conventional scaling laws cannot be accurately applied when blade profile alone is scaled. Indeed, the only parameter reasonably well predicted was the pressure rise attainable, but that was only accurate for fan aspect ratios greater than 0.17. Below this, the pressure rise generated reduces logarithmically toward zero. The study also reveals that no advantage is gained by using fans of aspect ratio greater than 0.3, as the maximum flow rate attainable decreases slightly above this. Overall, the scaling phenomena reported herein provide invaluable information for the future design of efficient low-profile cooling solutions that are to incorporate such fans.     

On-line decision support for take-off runway scheduling with uncertain taxi times at London Heathrow airport

This paper addresses the challenge of building an automated decision support methodology to tackle the complex problem faced every day by runway controllers at London Heathrow Airport. Aircraft taxi from stands to holding areas at the end of the take-off runway where they wait in queues for permission to take off. A runway controller attempts to find the best order for aircraft to take off. Sequence-dependent separation rules that depend upon aircraft size, departure route and speed group ensure that this is not a simple problem to solve. Take-off time slots on some aircraft and the need to avoid excessive delay for any aircraft make this an even more complicated problem. Making this decision at the holding area helps to avoid the problems of unpredictable push-back and taxi times, but introduces a number of complex spatial constraints that would not otherwise exist. The holding area allows some flexibility for interchange of aircraft between queues, but this is limited by its physical layout. These physical constraints are not usually included in academic models of the departure problem. However, any decision support system to support the take-off runway controller must include them. We show, in this paper, that a decision support system could help the controllers to significantly improve the departure sequence at busy times of the day, by considering the taxiing aircraft in addition to those already at the holding area. However, undertaking this re-introduces the issue of taxi time uncertainty, the effect of which we explicitly measure in these experiments. Empirical results are presented for experiments using real data from different times of the day, showing how the performance of the system varies depending upon the volume of traffic and the accuracy of the provided taxi time estimations. We conclude that the development of a good taxi time prediction system is key to maximising the benefits, although benefits can be observed even without this.