Effect of Season and Habitat on Two Congeneric Bat Species in a Fragmented Forest Landscape, Central Amazon, Brazil

Bats are an important component of Amazonian mammal communities but are often ignored during conventional biodiversity assessments. Much is therefore unknown regarding spatial and temporal forest use and the partitioning between different bat species in the community. The objectives of this study were to examine how different habitats and seasons affects the activity of two congeneric species (Pteronotus alitonus and P. rubiginosus), and how temporal partitioning of activity in these two species varies with habitat types and seasonality. I used ultrasound recordings of the two Pteronotus species collected in three different habitat types (continuous primary forest, secondary forest and 10ha forest fragments) and during two seasons (wet and dry) in the Biological Dynamics of Forest Fragments Project in central Amazon, Brazil. The activity levels of both Pteronotus species were found to significantly increase during the wet season, suggesting that insect abundance during the wet season would positively affect bat activity levels. Furthermore, P. alitonus had highest activity levels in secondary forest, whereas P. rubiginosus exhibited high activity levels in both primary and secondary forest. Forest fragments were least favoured by both species. The same patterns were found in spatial hourly activity. The results suggest that P. alitonus and P. rubiginosus spatially and temporally partition activity and that this partitioning may be a way to reduce competition

Resonance phenomena near thresholds

The trapping effect is investigated close to the elastic threshold. The nucleus is described as an Open quantum mechanical many-body system embedded in the continuum of decay channels. An ensemble of compound nucleus states with both discrete and resonance states is investigated in an energy-dependent formalism. It is shown that the discrete states can trap the resonance ones and also that the discrete states can directly influence the scattering cross section

Identification of differentially expressed genes in a Giardia lamblia WB C6 clone resistant to nitazoxanide and metronidazole

Objectives The characterization of differential gene expression in Giardia lamblia WB C6 strain C4 resistant to metronidazole and nitazoxanide using microarray technology and quantitative real-time PCR. Methods In a previous study, we created and characterized the G. lamblia WB C6 clone C4 resistant to nitazoxanide and metronidazole. In this study, using a microarray-based approach, we have identified open-reading frames (ORFs) that were differentially expressed in C4 when compared with its wild-type WB C6. Using quantitative real-time PCR, we have validated the expression patterns of some of those ORFs, focusing on chaperones such as heat-shock proteins in wild-type and C4 trophozoites. In order to induce an antigenic shift, trophozoites of both strains were subjected to a cycle of en- and excystation. Expression of selected genes and resistance to nitazoxanide and metronidazole were investigated after this cycle. Results Forty of a total of 9115 ORFs were found to be up-regulated and 46 to be down-regulated in C4 when compared with wild-type. After a cycle of en- and excystation, resistance of C4 to nitazoxanide and metronidazole was lost. Resistance formation and en-/excystation were correlated with changes in expression of ORFs encoding for major surface antigens such as the variant surface protein TSA417 or AS7 (‘antigenic shift'). Moreover, expression patterns of the cytosolic heat-shock protein HSP70 B2, HSP40, and of the previously identified nitazoxanide-binding proteins nitroreductase and protein disulphide isomerase PDI4 were correlated with resistance and loss of resistance after en-/excystation. C4 trophozoites had a higher thermotolerance level than wild-type trophozoites. After en-/excystation, this tolerance was lost. Conclusions These results suggest that resistance formation in Giardia to nitazoxanide and metronidazole is correlated with altered expression of genes involved in stress response such as heat-shock protein

Subchondral bone density distribution of the talus in clinically normal Labrador Retrievers

Background: Bones continually adapt their morphology to their load bearing function. At the level of the subchondral bone, the density distribution is highly correlated with the loading distribution of the joint. Therefore, subchondral bone density distribution can be used to study joint biomechanics non-invasively. In addition physiological and pathological joint loading is an important aspect of orthopaedic disease, and research focusing on joint biomechanics will benefit veterinary orthopaedics. This study was conducted to evaluate density distribution in the subchondral bone of the canine talus, as a parameter reflecting the long-term joint loading in the tarsocrural joint. Results: Two main density maxima were found, one proximally on the medial trochlear ridge and one distally on the lateral trochlear ridge. All joints showed very similar density distribution patterns and no significant differences were found in the localisation of the density maxima between left and right limbs and between dogs. Conclusions: Based on the density distribution the lateral trochlear ridge is most likely subjected to highest loads within the tarsocrural joint. The joint loading distribution is very similar between dogs of the same breed. In addition, the joint loading distribution supports previous suggestions of the important role of biomechanics in the development of OC lesions in the tarsus. Important benefits of computed tomographic osteoabsorptiometry (CTOAM), i.e. the possibility of in vivo imaging and temporal evaluation, make this technique a valuable addition to the field of veterinary orthopaedic research

Modelling the extreme storm surge in the western Baltic Sea on November 13, 1872, revisited

Die Küste, 92 - Online First - 1872 - An exceptional storm surge in the Balti

Funktion und Aktivierungsmechanismus eines schnell aktivierbaren Tissue Factor-Systems

Tissue Factor ist der physiologische Initiator der Blutgerinnung. Die Lokalisierung des Tissue Factors in der Gefäßwand verhindert in einem intakten Gefäß den Gerinnungsstart. In der vorliegenden Arbeit beobachteten wir, daß nach einer 5-minütigen Stimulation mit Kollagen Tissue Factor auf der Oberfläche von Plättchen-Leukozyten Komplexen präsentiert wurde. In einer Analyse der Komponenten der Plättchen-Leukozyten Komplexe auf ihren Tissue Factor Gehalt fanden wir Tissue Factor in Plättchen, nicht aber in den Leukozyten. Der Plättchen Tissue Factor war in der Lage die Fibrinbildung im Blut auszulösen. Wir fanden Tissue Factor außerdem auf Microvesikeln thrombozytären Ursprungs, die im Plasma konstitutiv vorhanden sind

Intravascular tissue factor initiates coagulation via circulating microvesicles and platelets

Although tissue factor (TF), the principial initiator of physiological coagulation and pathological thrombosis, has recently been proposed to be present in human blood, the functional significance and location of the intravascular TF is unknown. In the plasma portion of blood, we found TF to be mainly associated with circulating microvesicles. By cell sorting with the specific marker CD42b, platelet-derived microvesicles were identified as a major location of the plasma TF. This was confirmed by the presence of full-length TF in microvesicles acutely shedded from the activated platelets. TF was observed to be stored in the α-granules and the open canalicular system of resting platelets and to be exposed on the cell surface after platelet activation. Functional competence of the blood-based TF was enabled when the microvesicles and platelets adhered to neutrophils, as mediated by P-selectin and neutrophil counterreceptor (PSGL-1, CD18 integrins) interactions. Moreover, neutrophil-secreted oxygen radical species supported the intravascular TF activity. The pools of platelet and microvesicle TF contributed additively and to a comparable extent to the overall blood TF activity, indicating a substantial participation of the microvesicle TF. Our results introduce a new concept of TF-mediated coagulation crucially dependent on TF associated with microvesicles and activated platelets, which principally enables the entire coagulation system to proceed on a restricted cell surface