Design and characterization of a mode-splitting Ψ-junction

It will he shown In this paper, that the mode conversion factor (MCF) as defined for Y-junctions, can be profitably applied for the design of three branch junctions for splitting the three lowest-order modes of a channel waveguide. Accordingly, these so-called mode-splitting Ψ-junctions were designed for implementation in PECVD SiON-technology. Propagation calculations point to crosstalk levels well below -20 dB at 10-20 mm junction length. The produced Ψ-junctions show crosstalk of less than -17 dB, mainly originating from the nonhomogeneity of the refractive indexes of the SiON layers     

Impact on human health of Salmonella spp. on pork in The Netherlands and the anticipated effects of some currently proposed control strategies

Cell-cell and cell-extracellular matrix interactions are fundamental processes involved in cell migration and tissue remodeling. Both the cyclic regeneration of the human endometrium during the menstrual cycle as well as the process of embryo implantation involve such dynamic interactions. It has become quite clear that integrin adhesion molecules expressed on the surface of cells play critical roles in the transmission of signals from the extracellular milieu to the cells. It is these signals that presumably regulate the behavior of these cells during major morphogenetic processes. In recent years, work in human endometrium and trophoblasts has uncovered both the regulated and constitutive expression of integrin subunits and their extracellular matrix ligands in these tissues. In addition, attempts have been made to correlate pathological states related to either infertility or abnormal pregnancy to the aberrant expression of several of these integrins. The purpose of the present review is to describe briefly our present state of knowledge of the expression of integrins in human endometrium and trophoblasts and provide the reader with the necessary background needed to understand, at the cellular and molecular levels, processes in reproduction such as embryo implantation.     

Timing of the calcium intake and effect of calcium deficiency on behaviour and egg laying in captive great tits, Parus major

During recent years the world has experienced the reemergence of old communicable diseases and the emergence of new ones caused by novel pathogens such as the HIV virus and Borrelia burgdorferi. The problem consists mostly in the reemergence of old diseases but specially in industrialized countries new pathogens have also been described. Although the emergence of these infections in rare instances is due to genetic changes of pathogens to more virulent forms, most commonly they are due to changes in the environment and the host. Rapidly deteriorating living standards, disintegration of sanitation and public health infrastructure, cultural changes, migration and variations in behavior are some of the factors involved in the worldwide increase of infectious diseases. The degradation of natural habitats including forests and marine niches accompanied by climatic changes, are also playing an increasing role in the detrimental evolution of these diseases. The global emergence of these diseases calls into question the doctrine of epidemiological transition and directs us to scrutinize the paradigm that bases the prevention of these diseases solely on vaccination. The current situation also highlights the limitations of classical epidemiology in dealing with unexpected problems, and strongly suggests that this discipline should incorporate into its analysis findings from other fields, including ecological, climatological, and economical information. As most of the negative social and economical developments that impinge on the detrimental evolution of these diseases are increasing world-wide, it can be predicted that the problems posed by these infections will continue and perhaps worsen in the near future.     

Hypertonic milk replacers increase gastrointestinal permeability in healthy dairy calves

Hypertonic milk replacers are commonly used in animal production systems and their effect on the gastrointestinal system of young animals is insufficiently studied. Total lactose inclusion or its partial replacement with dextrose increases intestinal osmotic pressure, which may compromise gastrointestinal barrier function. In this experiment, we investigated the effect of increased osmolality of calf milk replacer (CMR) on gastrointestinal permeability in 30 Holstein Friesian (n = 17) or crossbred (n = 13) bull calves. The osmolality of CMR increased as result of a gradual replacement of lactose by monosaccharides (dextrose and galactose). Calves were acquired from dairy farms that followed a standardized protocol for colostrum management, including 3 feedings of colostrum in the first 24 h. Calves were then transported to the research facility between 0 and 3 d of age, fed a milk replacer with 0% dextrose twice daily for the first 2 wk of age, and subsequently exposed to their respective treatments from 3 until 7 wk of age. Meal size was 3.2 L at 3 wk of age and increased to 3.5 L at 7 wk of age. No solids were provided throughout the study and calves had ad libitum access to water. Treatments included 4 levels of dextrose inclusion (replacing lactose): 0% (L1, n = 5), 13.3% (L2, n = 5), 26.7% (L3, n = 5), and 40% (L4, n = 5) and an additional treatment (G+D, n = 10) that included 20% galactose and 20% dextrose and matched the galactose supply of L1 and the osmolality of L4. Carbohydrates were exchanged based on hexose equivalents. Across treatments, the estimated osmolality ranged from 439 (L1) to 611 mOsm/kg (L4 and G+D). Gastrointestinal permeability was assessed by fractional urinary recovery of indigestible markers (lactulose, d-mannitol, and Cr-EDTA) delivered as a single dose at 3 and 7 wk of age. Marker recoveries were expressed as percentage of oral dose and assessed in 6-h and 24-h quantitative urinary collections. Increasing the osmolality of the CMR linearly increased urinary Cr-EDTA and lactulose recoveries at 3 and 7 wk of age. Lactulose and Cr-EDTA recoveries did not differ between G+D and L4, suggesting that the source of monosaccharide (dextrose and galactose) in CMR had no effect on gastrointestinal permeability. The observed increase in gastrointestinal permeability to large molecules (Cr-EDTA and lactulose) with increased osmolality suggests that hypertonic CMR may compromise gastrointestinal barrier function.     

Effect of energy source in calf milk replacer on performance,digestibility, and gut permeability in rearing calves

Current calf milk replacer (CMR) compositions significantly differ from whole milk in their levels of energy, protein, and minerals. Energy source is one of the major differences, as CMR contains high levels of lactose, whereas whole milk contains higher levels of fat. The aim of this study was to determine the effect of partially exchanging lactose for fat on performance, digestibility, and gut permeability in calves fed twice daily on a high feeding plane. Lactose and fat were exchanged in the CMR formulation on a weight–weight basis. The CMR were isonitrogenous but not isoenergetic. A total of 60 male Holstein-Friesian calves were assigned to 1 of 30 blocks based on serum IgG, body weight, and date of collection after birth. Within each block, calves were randomly assigned to 1 of 2 treatments: high fat and high lactose. The CMR was provided twice daily until 49 d of age, followed by a gradual weaning period of 14 d. Starter, straw, and water were available ad libitum throughout the complete study. Exchanging lactose for fat did not affect growth; intakes of starter, straw, water, crude protein, or total energy; or apparent total-tract digestibility of nutrients. Gastrointestinal permeability was assessed by measuring the recovery of lactulose and Cr in 24-h urine and the Cr concentration and lactulose:d-mannitol ratio in serum following an oral pulse dose. Urinary recoveries of Cr and lactulose were generally low in both treatments but were higher in calves fed the high-fat CMR. Accordingly, the serum lactulose:d-mannitol ratio and serum Cr concentrations were higher in calves fed the high-fat CMR. In wk 1 and during the weaning transition, calves fed the high-fat CMR had significantly fewer abnormal fecal scores. In conclusion, exchanging lactose for fat in the CMR did not affect growth performance, total feed intake, or nutrient digestibility. The high-fat CMR was associated with an increase in permeability markers but positively influenced fecal scores in calves.     

Distinguishing traffic modes in analysing road safety development

Changes in mobility influence road safety. The effects of safety measures may even be overshadowed by the effects of temporary mobility fluctuations. Usually mobility is corrected for by defining risk as the ratio between fatalities and mobility. Due to lack of sufficient data, mobility is often approximated by car mobility. In this paper we will show that the resulting "general" risk is misleading. Stratification by traffic mode shows that the risk for car drivers, motorcyclists and truck drivers is roughly constant between 1950 and 1970 and that it has been decreasing exponentially afterwards. This contradicts the development of general risk, which has been decreasing the whole period between 1950 and today. Further stratification shows that stratification by traffic mode of the fatality alone is still insufficient. Changes in mobility of the other party in a crash are also important. The development of risk of car-car accidents differs significantly from that of single vehicle car accidents. A comparison between single vehicle motorcycle accidents and motorcycle-car accidents shows a similar discrepancy. Stratification of mobility by traffic mode, and of fatality data by the relevant traffic modes involved, can enhance the understanding of the influence of mobility on safety.