Do spherical tokamaks have a thermonuclear future?

This work has been initiated by the publication of a review by B.V.Kuteev et al., ??Intense Fusion Neutron Sources?? [Plasma Physics Reports 36, 281 (2010)]. It is stated that the key thesis of the above review that a spherical tokamak can be recommended for research neutron sources and for demonstration hybrid systems as an alternative to expensive ??classical?? tokamaks of the JET and ITER type is inconsistent. The analysis of the experimental material obtained during the last 10 years in the course of studies on the existing spherical tokamaks shows that the TIN-ST fusion neutron source spherical tokamak proposed by the authors of the review and intended, according to the authors?? opinion, to replace ??monsters?? in view of its table-top dimensions (2 m³) and laboratory-level energetics cannot be transformed into any noticeable stationary megawatt-power neutron source competing with the existing classical tokamaks (in particular, with JET with its quasi-steady DT fusion power at a level of 5 MW). Namely, the maximum plasma current in the proposed tokamak will be not 3 MA, as the authors suppose erroneously, but, according to the present-day practice of spherical tokamaks, within 0.6?C0.7 MA, which will lead to a reduction on the neutron flux by two to three orders of magnitude from the expected 5 MW. The possibility of the maintenance of the stationary process itself even in such a ??weakened?? spherical tokamak is very doubtful. The experience of the largest existing devices of this type (such as NSTX and MAST) has shown that they are incapable of operating even in a quasi-steady operating mode, because the discharge in them is spontaneously interrupted about 1 s after the beginning of the current pulse, although its expected duration is of up to 5 s. The nature of this phenomenon is the subject of further study of the physics of spherical tokamaks. This work deals with a critical analysis of the available experimental data concerning such tokamaks and a discussion of the potential possibility of their use in thermonuclear research.     

Do facts have a place in science?

The use of the word ‘fact’ in science is discussed. It is suggested that the everyday meaning of the term is assumed when it is used in science and that this can create problems. Some possible ways of overcoming these difficulties are indicated.     

Does zoo herpetology have a future?

Fifty-two North American zoo reptile and amphibian departments were surveyed to determine their contributions to recognized American Zoo and Aquarium Association (AZA)-sponsored programs and formalized research projects over the past 10 years. Surveys also requested information concerning the allocation of resources for conservation and research programs, staff educational background, and entry level salaries. Twenty-two institutions responded to the survey, collectively indicating a total of 164 technical papers, 16 field studies, and 101 non-technical articles completed between 1987 and 1997. Of the 164 technical papers published, 130 (79%) were contributed by three institutions. Of the 16 field studies, seven were outside the United States, whereas nine focused on native species and ecosystems. Six of the reported field studies involved only financial or logistical support. Of the 101 non-technical articles, 42 (42%) were contributed by a single institution. Twenty-one formalized in-house research projects were reported. However, only four appeared to have a clearly defined objective. Survey respondents also reported nine species of reptiles and one amphibian taxon are managed by Species Survival Plans (SSPs). There are currently 12 Taxon Advisory Group (TAG) coordinators, with four of the current coordinators having served on multiple TAG committees. There are 41 AZA-approved studbooks for reptiles and two for amphibians, with 29 having actually been published to date. The average starting salary reported in our survey for entry level keeper positions was $19,500 (range, $13,500–30,000). The average level of education reported was high school graduate. There was no correlation between productivity and higher wages, or level of education. Only one institution received funding specifically for research. We conclude that zoo herpetology departments are not realizing their potential for formalized research and conservation projects and propose recommendations for future involvement. Zoo Biol 17:453–462, 1998. © 1998 Wiley-Liss, Inc.     

Do tastants have a smell?

The stimuli used in taste research are usually considered to be odourless. This was tested in two experiments with aqueous solutions of two representative compounds for each of the five taste qualities including umami. In the first experiment elderly and young subjects rated the intensity and pleasantness of three concentrations of the stimuli, while wearing or not wearing a noseclip. Saliva production was also measured. Blocking olfaction only influenced salivation for umami. It reduced taste intensity ratings, but as in an earlier experiment with the same compounds in food products, this effect was stronger in the young, who also liked the stimuli better wearing the noseclip. In the second experiment, another group of young people tried to detect the odours of the tastants dissolved in demineralized, double-distilled or Evian water. A considerable number of subjects could regularly detect seven of the ten tastants by olfaction and the extent to which they did correlated significantly with the reduction in taste intensity ratings for the different tastants found in the first experiment. We suggest that most tastants can be smelled and that this smell contributes to taste intensity ratings.     

Do DNA microarrays have their future behind them?

The first report on DNA microarray technology appeared in Science in 1995. Starting from gene expression profiling, its application fields have considerably evolved and extend from microbiology to cancer study. DNA microarrays are now routinely used for the detection of single nucleotide polymorphisms, microRNAs analysis, study of copy number variation, CpG methylations detection.... Furthermore, the approval of DNA microarray technology by US Food and Drug Administration has opened the door to new applications in clinical diagnostics. At the same time, DNA arrays have to face the concurrence of the latest generation of very high throughput sequencing devices which are predicted to make the microarray technology obsolete. This review will discuss on this paradoxical situation.     

Do you have any regrets about entering medicine?

Do today''s students have any second thoughts about their decision to pursue a career in medicine? Gabriel Leung, who graduates in June from the University of Western Ontario, considers the problems and dilemmas that have confronted him and his classmates during their short careers and muses on the uncertain future today''s physicians face.     

Do small animals have a biogeography?

It has been stated that small organisms do not have barriers for distribution and will not show biogeographic discreteness. General models for size-mediated biogeographies establish a transition region between ubiquitous dispersal and restricted biogeography at about 1–10 mm. We tested patterns of distribution versus size with water mites, a group of freshwater organisms with sizes between 300 μm and 10 mm.We compiled a list of all known water mite species for Sierra del Guadarrama (a mountain range in the centre of the Iberian Peninsula) from different authors and our own studies in the area. Recorded habitats include lotic, lentic and interstitial environments. Species body size and world distribution were drawn from our work and published specialized taxonomic literature. The null hypothesis was that distribution is size-independent. The relationship between distribution and size was approached via analysis of variance and between size and habitat via logistic regression. Contrary to expectations, there is no special relationship between water mite size and area size distribution. On the other hand, water mite size is differentially distributed among habitats, although this ecological sorting is very weak. Larger water mites are more common in lentic habitats and smaller water mites in lotic habitats. Size-dependent distribution in which small organisms tend to be cosmopolitan breaks down when the particular biology comes into play. Water mites do not fit a previously proposed size-dependent biogeographical distribution, and are in accordance with similar data published on Tardigrada, Rotifera, Gastrotricha and the like.     

Do corticosteroids have a role in treating Ebola virus disease?

<正>Dear Editor,Humans have been fighting Ebola virus disease(EVD)since its first outbreak in 1976 in Yambuku village in the Democratic Republic of the Congo(previously Zaire).EVD is part of the Filoviridae family of viruses that includes Ebola and Marburg viruses.To date,EVD,one of the most deadly communicable diseases known to humans,has had15 outbreaks in Africa.In 2014,the most severe and complicated outbreak yet swept through the West African countries of Guinea,Liberia,Nigeria,Senegal and Sierra Leone,