CULTIVATION OF AFRICAN AND SOUTH AMERICAN TRYPANOSOMES OF MEDICAL OR VETERINARY IMPORTANCE

Today most parasite stages of the African trypanosome species can be grown in vitro. The co-cultivation of insect or mammalian cells is still necessary for the cultivation of some of the insect or mammalian forms. However, simple culture systems that produce high parasite yields cost-effectively have still to be found, with the exception of the procyclic trypomastigote forms which can easily be grown in semi-defined media. A culture system for the production of metacyclic forms in large numbers is a major goal for future research. The different stages of T. cruzi can easily be grown in large quantities. Even metacyclic forms can be produced in large numbers in monophasic media without host cells. The vertebrate forms, grown in the presence of mammalian cells, can also be grown in quantities sufficient for most biochemical and immunological investigations. Either amastigotes or hypomastigotes can be obtained from cultures. They can be separted from host cells or debris by chromatography or gradient centrifugatio

Caught in the act: Implications for the increasing abundance of mafic enclaves during the eruption of the Soufriere Hills Volcano, Montserrat

An exceptional opportunity to sample several large blocks sourced from the same region of the growing Soufrière Hills lava dome has documented a significant increase in the presence of mafic enclaves in the host andesite during the course of a long-lived eruptive episode with several phases. In 1997 (Phase I) mafic inclusions comprised ~1 volume percent of erupted material; in 2007 (Phase III) deposits their volumetric abundance increased to 5–7 percent. A broader range of geochemically distinctive types occurs amongst the 2007 enclaves. Crystal-poor enclaves generally have the least evolved (basaltic) compositions; porphyritic enclaves represent compositions intermediate between basaltic and andesitic compositions. The absence of porphyritic enclaves prior to Phase III magmatism at Soufrière Hills Volcano suggests that a mixing event occurred during the course of the current eruptive episode, providing direct evidence consistent with geophysical observations that the system is continuously re-invigorated from depth

Left ventricular flow from apex to base during systole and isovolumic relaxation in a patient with hypertrophic cardiomyopathy and midventricular obstruction

The occurrence of a left ventricular anterograde flow velocity (maximal: 3·9m . s−1) is demonstrated in a 32-year-old patient with hypertrophic cardioinyopathy and midveniricular obstruction, beginning at early systole and persisting throughout the isovolumic relaxation. Cardiac catheterization with simultaneous dual high fidelity pressure measurements in the apical and basal chambers confirmed the presence of the Doppler maximal instantaneous pressure gradient of 60 mmHg. Contrast left ventricular angiography excluded apical dyskinesia. In the two intracavity compartments, isovolumic relaxation time and the time constant of pressure decay (τ) were abnormal whereby τ was more delayed in the apical than in the basal portion. The presence of an apical high pressure zone during systole with impeded and delayed emptying through the midventricular obstacle and the late onset and prolongation of relaxation are thought to be the cause of the intraventricular flow from apex to base lasting from early systole throughout isovolumic relaxatio

Scientists as storytellers: the explanatory power of stories told about environmental crises

This paper examines how storytelling functions to share and to shape knowledge, particularly when scientific knowledge is uncertain because of rapid environmental change. Narratives or stories are the descriptive sequencing of events to make a point. In comparison with scientific deduction, the point (plot) of a story can be either implicit or explicit, and causal links between events in the story are interpretative, rendering narrative a looser inferential framework. We explore how storytelling (the process) and stories (or narratives) involving scientists can make sense of environmental crises, where conditions change rapidly and natural, social, and scientific systems collide. We use the example of the Soufrière Hills volcanic eruption (Montserrat) and scientists' experiences of the events during that time. We used 37 stories gathered from seven semi-structured interviews and one group interview (five scientists). We wanted to understand whether these stories generate or highlight knowledge and information that do not necessarily appear in more conventional scientific literature produced in relation to environmental crisis and how that knowledge explicitly or implicitly shapes future actions and views. Through our analysis of the value these stories bring to volcanic risk reduction, we argue that scientists create and transmit important knowledge about risk reduction through the stories they tell one another. In our example storytelling and stories are used in several ways: (1) evidencing the value of robust long-term monitoring strategies during crises, (2) exploring the current limits of scientific rationality and the role of instinct in a crisis, and (3) the examination of the interactions and outcomes of wide-ranging drivers of population risk. More broadly these stories allowed for the emotional intensity of these experiences to be acknowledged and discussed; the actions and outcomes of the storytelling are important. This is not about the “story” of research findings but the sharing of experience and important knowledge about how to manage and cope with volcanic crises. We suggest that storytelling frameworks could be better harnessed in both volcanic and other contexts