Combined cryopreservation of canine ejaculates collected at a one-hour interval increases semen doses for artificial insemination without negative effects on post-thaw sperm characteristics

A limiting factor in canine artificial insemination (AI) is the low number of insemination doses obtained per ejaculate. In this study, semen was collected from dogs (n = 28) either once and frozen directly after collection or the same dogs were submitted to a dual semen collection with a 1-hr interval and the two ejaculates were combined for cryopreservation. We hypothesized that combining two ejaculates increases semen doses per cryopreservation process without negative effects on semen characteristics. Total sperm count was lower in semen from a single semen collection in comparison with the combination of the first and second ejaculate of a dual semen collection (p < .001). The percentage of motile and membrane-intact spermatozoa determined by computer-assisted sperm analysis (CASA) in raw semen did not differ between single and combined dual ejaculates and was reduced (p < .001) by cryopreservation to the same extent in single (motility 73.7 ± 1.8%, membrane integrity 65.6 ± 2.2%) and combined dual ejaculates (motility 72.7 ± 2.3%, membrane integrity 64.6 ± 2.5%). The percentage of spermatozoa with morphological defects increased after cryopreservation (p < .001) but was similar in single and combined dual ejaculates. The CASA sperm velocity parameters decreased with cryopreservation (p < .001) but did not differ between single and combined dual ejaculates. The number of insemination doses increased from 2.7 ± 0.4 for single to 4.7 ± 0.8 for combined dual ejaculates (p < .01), based on 100 million motile spermatozoa per frozen-thawed semen dose. In conclusion, combining two ejaculates collected at short interval for one cryopreservation process increases the number of AI doses without compromising semen quality.     

Chloroquine resistance in Plasmodium falciparum malaria parasites conferred by pfcrt mutations

Plasmodium falciparum chloroquine resistance is a major cause of worldwide increases in malaria mortality and morbidity. Recent laboratory and clinical studies have associated chloroquine resistance with point mutations in the gene pfcrt. However, direct proof of a causal relationship has remained elusive and most models have posited a multigenic basis of resistance. Here, we provide conclusive evidence that mutant haplotypes of the pfcrt gene product of Asian, African, or South American origin confer chloroquine resistance with characteristic verapamil reversibility and reduced chloroquine accumulation. pfcrt mutations increased susceptibility to artemisinin and quinine and minimally affected amodiaquine activity; hence, these antimalarials warrant further investigation as agents to control chloroquine-resistant falciparum malaria.     

Effects of a 61.7 km ride on magnesium and calcium homeostasis in well trained endurance horses

The adequacy of the dietary supply of Mg and Ca was evaluated in seven well trained endurance horses completing a 61.7 km ride. The horses received excessive amounts of dietary magnesium before and during the ride. Blood samples were taken one hour before the start, at the first and second veterinary gate, directly and 1 and 2 hours after the finish. The mean body weight loss was 20.1 ± 3.9 kg which implied a body weight reduction of 4.6 ± 1.0%. No major downward changes of the concentrations of the total and ionized concentrations of calcium and magnesium and erythrocyte Mg concentrations were observed during the ride in response to the Mg and Ca loss via sweat. Also the concentrations of parathyroid hormone and 1,25-dihydroxyvitamin D were not increased. These results demonstrate that under the conditions of this study sufficient amounts of Mg and Ca were available from the diet, from additional supplementation during the ride and from body stores.     

Estimation of local probabilities for exceeding threshold values in environmental monitoring

Contour or isopleth maps of regionalized variables are widely used in decision making without regard for the inherent uncertainty of interpolated contours. One concept for addressing the accuracy of contours given the data is the computation of the conditional probability of the value being lower than the contour. Two simple techniques for an approximate computation, indicator kriging and approximation by normal distribution quantiles, are applied to immission data. Since the assumption of a stationary underlying process does not seem justifiable, a moving windows technique is adopted.     

Bodenkundliche Untersuchungen an Deckschichten in N-Togo

Pedological Examination of “Covering Layers” (Deckschichten) in Northern Togo “Covering layers” (Deckschichten) in northern Togo occur regularly and are widespread. Their composition varies according to the morphological situation. Only covering layers of the same morphological position are comparable. The uppermost covering layer is a product of subrecent geomorphodynamic activity. The origin of the material is still unknown. The contribution of termites to the genesis of covering layers in N-Togo is insignificant. The covering layer is the parent material of recent soil forming processes. The soils are generally stratified with polycyclic genesis. The composition, the thickness and the number of covering layers are causing the agronomic potential of these soils.     

Distribution of the timber quality attribute ‘knot surface’ in logs of Fagus sylvatica L. from pure and mixed forest stands

European Journal of Forest Research - Research on mixed forests has mostly focused on tree growth and productivity, or resistance and resilience in changing climate conditions, but only rarely on...     

Fast routing in road networks with transit nodes

When you drive to somewhere far away, you will leave your current location via one of only a few important traffic junctions. Starting from this informal observation, we developed an algorithmic approach, transit node routing, that allows us to reduce quickest path queries in road networks to a small number of table lookups. For road maps of Western Europe and the United States, our best query times improved over the best previously published figures by two orders of magnitude. This is also more than one million times faster than the best known algorithm for general networks.