Dynamic connectivity of temporary wetlands in the southern Great Plains

We quantified fluctuations in the status of individual patches (wetlands) in supporting connectivity within a network of playas, temporary wetlands of the southern Great Plains of North America that are loci for regional biodiversity. We used remote sensing imagery to delineate the location of surface waters in >8,000 playa basins in a ~31,900 km² portion of Texas and quantified connectivity in this region from 2007 to 2011. We ranked playas as stepping-stones, cutpoints, and hubs at different levels of environmental conditions (regionally wet, dry, and average periods of precipitation) for dispersal distances ranging from 0.5 to 34 km, representing a range of species’ vagilities, to provide baseline dynamics within an area likely to experience disrupted connectivity due to anthropogenic activities. An individual playa’s status as a stepping-stone, cutpoint, or hub was highly variable over time (only a single playa was a top 20 stepping-stone, cutpoint, or hub in >50 % of all of the dates examined). Coalescence of the inundated playa network usually occurred at ≥10 km dispersal distance and depended on wetland density, indicating that critical thresholds in connectivity arose from synergistic effects of dispersal ability (spatial scale) and wet playa occurrence (a function of precipitation). Organisms with dispersal capabilities limited to <10 km routinely experienced effective isolation during our study. Connectivity is thus a dynamic emergent landscape property, so management to maintain connectivity for wildlife within ephemeral habitats like inundated playas will need to move beyond a patch-based focus to a network focus by including connectivity as a dynamic landscape property.     

Investigations with enzyme-linked immunosorbent assays for Trichinella spiralis and Toxoplasma gondii in the Dutch 'Integrated Quality Control for finishing pigs' research project.

In the framework of the Dutch field trial 'Integrated Quality Control (IQC) for finishing pigs' ELISA (screening) techniques were used to detect animals seropositive for Toxoplasma gondii and/or Trichinella spiralis. The aim was to determine whether farms which consistently delivered seropositive pigs could be detected and monitored (defined as 'problem farms'). The investigation involved 120 farms and three slaughterhouses, and a total of 23,348 serum samples were examined. In addition, all pigs were also screened for the presence of Trichinella spiralis with the digestion method (pooled samples). The prevalence of seropositivity for Trichinella spiralis and Toxoplasma gondii was 0.3% and 2.1% respectively. Parasitological examinations concerning T. spiralis were negative. Considering the characteristics of the used methodology, the conclusion was drawn that there were no parasitological or serological indications for T. spiralis infections, and that with respect to T. gondii the infection rate seemed to be equally low for all farms involved. In addition, a longitudinal pilot study during a whole finishing period was undertaken at two finishing farms. Animals seropositive for Toxoplasma gondii were found from the earliest days of the finishing period. Housing and management may (still) play an important role in the prevention of contact with this parasite.     

Predictability of post mortem abnormalities in shipments of slaughter pigs as an aid for meat inspection

This paper reports on the predictability of post mortem abnormalities in individual deliveries of pigs, shipped from the fattening herd to the slaughterhouse. The percentage of pigs in a delivery having post mortem abnormalities was expressed in a Meat Inspection Index. This index is based on data about relevant abnormalities, weighted on the specific significance of each for meat inspection. It was investigated whether Meat Inspection Indices of previous deliveries of pigs could be used for prediction of indices of future deliveries. Results suggest that the Meat Inspection Index cannot be used in such a predictive capacity, partly because of great variation among individual shipments. However, a Meat Inspection Index could play a role in signalling farms that are likely to deliver pigs with a higher level of abnormalities. More attention could then be paid to animals coming from these herds.     

Large and rapid melt-induced velocity changes in the ablation zone of the Greenland Ice Sheet

Continuous Global Positioning System observations reveal rapid and large ice velocity fluctuations in the western ablation zone of the Greenland Ice Sheet. Within days, ice velocity reacts to increased meltwater production and increases by a factor of 4. Such a response is much stronger and much faster than previously reported. Over a longer period of 17 years, annual ice velocities have decreased slightly, which suggests that the englacial hydraulic system adjusts constantly to the variable meltwater input, which results in a more or less constant ice flux over the years. The positive-feedback mechanism between melt rate and ice velocity appears to be a seasonal process that may have only a limited effect on the response of the ice sheet to climate warming over the next decades.     

Use of information from Pig finishing herds for meat inspection purposes

Summary

In a field trial on Integrated Quality Control of finishing pigs we evaluated information written on Quality Information Cards (QUIC) for meat inspection purposes. These cards were sent with 3747 shipments of pigs going from the finishing herd to the slaughterhouse. Pig suppliers answered five questions dealing with health problems and the use of drugs during the finishing period By comparing QUIC answers to recorded post‐mortem abnormalities, we found that the information on the QUIC had some, albeit low, predictive value with respect to the abnormalities ‘arthritis’, ‘condemned liver’ and lung lesions. Shipments without a QUIC or with a faulty QUIC were considered ‘suspect’ because higher levels of abnormalities were found in these shipments. These results indicate the potential use of a QUIC.     

Growth analyses of tomato genotypes grown under low night temperatures and low light intensity

Summary In three experiments the growth of 16 genotypes of tomato was examined. The plants were raised in growth rooms at a day temperature of 19°C and night temperatures of 14, 10 or 6°C respectively under a light intensity of 24 Wm^-2 visible radiation and a daylength of 8 hours. The results were analysed by a multivariate analysis of variance.Relative growth rate (RGR), leaf area ratio (LAR), specific leaf area (SLA) and leaf weight ratio (LWR) decreased with time. The change in net assimilation rate (NAR) was small. The decrease in RGR was mainly due to the decrease in LAR.RGR, LAR and SLA were lower and LWR slightly higher at lower night temperatures. NAR was hardly affected. The lower RGR at lower night temperatures was mainly due to a lower SLA.Significant differences between genotypes were found in total dry weight, NAR, LAR, SLA and LWR, but hardly in RGR. Significant genotype × temperature interactions occurred.LAR and SLA were positively, NAR and LAR, and NAR and SLA negatively correlated.     

Some effects of temperature on the shoot growth of cherry seedlings

Summary In the phytotron of our Institute the effect was studied of different day and night temperatures on the shoot growth of first- and second-year seedlings of Limburgse Boskriek (Prunus avium L.) grown under natural daylength conditions.It was found that, after termination of growth, significant differences occurring simultaneously in shoot length and leaf number between the temperature treatments were mainly due to the effect of the day or night temperature on the duration of growth. In some cases these differences were also influenced by the effect of temperature on the rate of growth. Within the range of temperatures studied, no effect of the night temperature on the rate of growth was observed.     

Cervical disc width index is a reliable parameter and consistent in young growing Dutch Warmblood horses

Intervertebral disc disease, as well as the associated alteration of the radiographic intervertebral disc space width, has been reported in horses. Disc height index (DHI) has proven to be an accurate and objective parameter in other species but data related to this parameter are lacking in horses. Therefore, the aims of this retrospective longitudinal diagnostic accuracy study were (a) to evaluate the reliability of measurements within and between observers of the equine Disc Width Index (EDWI) as a parameter for radiographic equine cervical intervertebral disc space width, and (b) to evaluate the sequential development of the EDWI over time. For this, EDWI from all intervertebral disc spaces between second cervical (C) to first thoracic (Th) vertebrae were obtained in a group of 39 Dutch Warmblood horses at 1, 5, and 18 months of age, by one European College of Veterinary Diagnostic Imaging (ECVDI) board‐certified veterinary radiologist (S.V.) and two veterinary students. Bland‐Altmann plots and intraclass Correlation Coefficient revealed a good intra‐ and interobserver agreement. A linear mixed‐effect model did reveal that mean EDWI increases significantly toward the caudal cervical spine, but did not differ significantly for a certain location over time or between sexes. Spearman's rank test did show a significant correlation between the vertebral alignment angle induced by different head‐neck positions and a normalized EDWI (ρ = 0.33, P < .0001). Student's t‐test revealed that the presence of C6‐C7 transposition of the transverse processes did not influence EDWI significantly. It was concluded that EDWI represents a reliable parameter for equine cervical radiographic intervertebral disc space width. Practical implementation of EDWI warrants monitoring in a group of adult horses while maintaining a standardized head‐neck position.