420 research outputs found

    Planetary radio astronomy observations from Voyager-2 near Saturn

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    Voyager-2 planetry radio astronomy measurements obtained near Saturn are discussed. They indicate that Saturnian kilometric radiation is emitted by a strong, dayside source at auroral latitudes in the northern hemisphere and by a weaker (by more than an order of magnitude) source at complementary latitudes in the southern hemisphere. These emissions are variable both due to Saturn's rotation and, on longer time scales, probably due to influences of the solar wind and the satellite Dione. The Saturn electrostatic discharge bursts first discovered by Voyager-1 and attributed to emissions from the B-ring were again observed with the same broadband spectral properties and a 10(h)11(m) + or - 5(m) episodic recurrence period but with an occurrence frequency of only of about 30 percent of that detected with Voyager-1. During the crossing of the ring plane at a distance of 2.88 R sub S, an intense noise event is interpreted to be consequence of the impact/vaporization/ionization of charged micron-size G-ring particles distributed over a total vertical thickness of about 1500 km

    Serological evidence for human cystic echinococcosis in Slovenia

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    <p>Abstract</p> <p>Background</p> <p>Cystic echinococcosis (CE) is caused by the larva of tapeworm <it>Echinococcus granulosus</it>. Dogs and other canids are the primary definitive hosts for this parasite. CE may develop after accidental ingestion of tapeworm eggs, excreted with the feces of these animals. In the intestine, the larvae released from the eggs are nested in the liver, lungs or other organs of livestock as intermediate hosts and humans as aberrant hosts. The aim of this study was to examine serologically whether some of the patients in Slovenia, suspected of CE by imaging findings in the liver or lungs had been infected with the larva of <it>Echinococcus granulosus</it>.</p> <p>Methods</p> <p>Between January 1, 2002 and the end of December 2006, 1323 patients suspected of having echinococcosis were screened serologically by indirect haemagglutination assay (IHA). For confirmation and differentiation of <it>Echinococcus </it>spp. infection, the sera of IHA-positive patients were then retested by western blot (WB).</p> <p>Results</p> <p>Out of 127 IHA-positive sera, 34 sera were confirmed by WB and considered specific for CE. Of 34 sera of CE-positive patients sera, 32 corresponded to the characteristic imaging findings of a liver cysts and 2 to those of lung cysts. The mean age of CE-positive patients was 58.3 years. No significant differences were found between the CE-positive patients in regard to their sex.</p> <p>Conclusion</p> <p>In the study, it was found out that CE was mostly spread in the same area of Slovenia as in the past, but its prevalence decreased from 4.8 per 10<sup>5 </sup>inhabitants in the period 1956–1968 to 1.7 per 10<sup>5 </sup>inhabitants in the period 2002–2006. In spite of the decreased prevalence of CE in the last years, it is suggested that clinicians and public health authorities, especially in the eastern parts of Slovenia where the most CE patients come from, should pay greater attention to this disease in the future.</p

    Fragmentation and systematics of the Pygmy Dipole Resonance in the stable N=82 isotones

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    The low-lying electric dipole (E1) strength in the semi-magic nucleus 136Xe has been measured which finalizes the systematic survey to investigate the so-called pygmy dipole resonance (PDR) in all stable even N=82 isotones with the method of nuclear resonance fluorescence using real photons in the entrance channel. In all cases, a fragmented resonance-like structure of E1 strength is observed in the energy region 5 MeV to 8 MeV. An analysis of the fragmentation of the strength reveals that the degree of fragmentation decreases towards the proton-deficient isotones while the total integrated strength increases indicating a dependence of the total strength on the neutron-to-proton ratio. The experimental results are compared to microscopic calculations within the quasi-particle phonon model (QPM). The calculation includes complex configurations of up to three phonons and is able to reproduce also the fragmentation of the E1 strength which allows to draw conclusions on the damping of the PDR. Calculations and experimental data are in good agreement in the degree of fragmentation and also in the integrated strength if the sensitivity limit of the experiments is taken into account

    MARCH WET AVALANCHE PREDICTION AT BRIDGER BOWL SKI AREA, MONTANA

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    ABSTRACT: Few avalanche forecast models are tailored specifically for wet avalanche forecasting. Bridger Bowl (intermountain climate) is a good area to develop a wet avalanche probability model. The primary archived data consists of eight variables. The archived data for March from 1968 to 2001 (1996 data unavailable) were used to develop 68 predictor variables related to temperature, snowpack settlement, and precipitation. The original dataset was divided into days with snowfall in the past 48 hours (new snow) and days without (old snow). There were 33 significant old snow variables and 22 significant new snow variables. Six variables are common to both old and new snow. The best predictor variables for old and new snow are different. The variables were analyzed with binomial logistic regression to produce probability models for old snow and for new snow wet avalanche conditions. The old snow model uses the prediction day minimum temperature and the two-day change in total snow depth as predictor variables and has a 89% overall success rate. However, the majority of this success is due to correct prediction of days without wet avalanches (96% of all correct predictions). The new snow model uses the prediction day minimum temperature and three-day cumulative new snow water equivalent as predictor variables, but is less useful. The models are applicable only to Bridger Bowl. The numerical forecast models can be used as one of the tools in the forecasting toolbox but limited data and complexity of process require that the decisions about closure remain in the hands of the ski patrol

    MARCH WET AVALANCHE PREDICTION AT BRIDGER BOWL SKI AREA, MONTANA

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    ABSTRACT: Few avalanche forecast models are tailored specifically for wet avalanche forecasting. Bridger Bowl (intermountain climate) is a good area to develop a wet avalanche probability model. The primary archived data consists of eight variables. The archived data for March from 1968 to 2001 (1996 data unavailable) were used to develop 68 predictor variables related to temperature, snowpack settlement, and precipitation. The original dataset was divided into days with snowfall in the past 48 hours (new snow) and days without (old snow). There were 33 significant old snow variables and 22 significant new snow variables. Six variables are common to both old and new snow. The best predictor variables for old and new snow are different. The variables were analyzed with binomial logistic regression to produce probability models for old snow and for new snow wet avalanche conditions. The old snow model uses the prediction day minimum temperature and the two-day change in total snow depth as predictor variables and has a 89% overall success rate. However, the majority of this success is due to correct prediction of days without wet avalanches (96% of all correct predictions). The new snow model uses the prediction day minimum temperature and three-day cumulative new snow water equivalent as predictor variables, but is less useful. The models are applicable only to Bridger Bowl. The numerical forecast models can be used as one of the tools in the forecasting toolbox but limited data and complexity of process require that the decisions about closure remain in the hands of the ski patrol

    The geographical distribution and prevalence of Echinococcus multilocularis in animals in the European Union and adjacent countries : a systematic review and meta-analysis

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    Background This study aimed to provide a systematic review on the geographical distribution of Echinococcus multilocularis in definitive and intermediate hosts in the European Union (EU) and adjacent countries (AC). The relative importance of the different host species in the life-cycle of this parasite was highlighted and gaps in our knowledge regarding these hosts were identified. Methods Six databases were searched for primary research studies published from 1900 to 2015. From a total of 2,805 identified scientific papers, 244 publications were used for meta-analyses. Results Studies in 21 countries reported the presence of E. multilocularis in red foxes, with the following pooled prevalence (PP): low (≤ 1 %; Denmark, Slovenia and Sweden); medium (> 1 % to 10 %; Czech Republic, Estonia, France, Germany, Latvia, Lithuania, Poland, Slovakia, Liechtenstein and Switzerland). Studies from Finland, Ireland, the United Kingdom and Norway reported the absence of E. multilocularis in red foxes. However, E. multilocularis was detected in Arctic foxes from the Arctic Archipelago of Svalbard in Norway. Conclusions Raccoon dogs (PP 2.2 %), golden jackals (PP 4.7 %) and wolves (PP 1.4 %) showed a higher E. multilocularis PP than dogs (PP 0.3 %) and cats (PP 0.5 %). High E. multilocularis PP in raccoon dogs and golden jackals correlated with high PP in foxes. For intermediate hosts (IHs), muskrats (PP 4.2 %) and arvicolids (PP 6.0 %) showed similar E. multilocularis PP as sylvatic definitive hosts (DHs), excluding foxes. Nutrias (PP 1.0 %) and murids (PP 1.1 %) could play a role in the life-cycle of E. multilocularis in areas with medium to high PP in red foxes. In areas with low PP in foxes, no other DH was found infected with E. multilocularis. When fox E. multilocularis PP was >3 %, raccoon dogs and golden jackals could play a similar role as foxes. In areas with high E. multilocularis fox PP, the wolf emerged as a potentially important DH. Dogs and cats could be irrelevant in the life-cycle of the parasite in Europe, although dogs could be important for parasite introduction into non-endemic areas. Muskrats and arvicolids are important IHs. Swine, insectivores, murids and nutrias seem to play a minor or no role in the life-cycle of the parasite within the EU and ACs

    The high-efficiency {\gamma}-ray spectroscopy setup {\gamma}3 at HI{\gamma}S

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    The existing Nuclear Resonance Fluorescence (NRF) setup at the HI{\gamma}S facility at the Triangle Universities Nuclear Laboratory at Duke University has been extended in order to perform {\gamma}-{\gamma} coincidence experiments. The new setup combines large volume LaBr3:Ce detectors and high resolution HPGe detectors in a very close geometry to offer high efficiency, high energy resolution as well as high count rate capabilities at the same time. The combination of a highly efficient {\gamma}-ray spectroscopy setup with the mono-energetic high-intensity photon beam of HI{\gamma}S provides a worldwide unique experimental facility to investigate the {\gamma}-decay pattern of dipole excitations in atomic nuclei. The performance of the new setup has been assessed by studying the nucleus \sulfur at 8.125 MeV beam energy. The {\gamma}-decay branching ratio from the 1+1^+ level at 8125.4 keV to the first excited 2+2^+ state was determined to 15.7(3)%.Comment: 9 pages, 11 figure

    Dipole Strength Distributions from HIGS Experiments

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    A series of photon scattering experiments has been performed on the double-beta decay partners 76Ge and 76Se, in order to investigate their dipole response up to the neutron separation threshold. Gamma-ray beams from bremsstrahlung at the S-DALINAC and from Compton-backscattering at HIGS have been used to measure absolute cross sections and parities of dipole excited states, respectively. The HIGS data allows for indirect measurement of averaged branching ratios, which leads to significant corrections in the observed excitation cross sections. Results are compared to statistical calculations, to test photon strength functions and the Axel-Brink hypothesi

    Post-treatment follow-up study of abdominal cystic echinococcosis in Tibetan communities of northwest Sichuan Province, China

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    Background: Human cystic echinococcosis (CE), caused by the larval stage of Echinococcus granulosus, with the liver as the most frequently affected organ, is known to be highly endemic in Tibetan communities of northwest Sichuan Province. Antiparasitic treatment with albendazole remains the primary choice for the great majority of patients in this resource-poor remote area, though surgery is the most common approach for CE therapy that has the potential to remove cysts and lead to complete cure. The current prospective study aimed to assess the effectiveness of community based use of cyclic albendazole treatment in Tibetan CE cases, and concurrently monitor the changes of serum specific antibody levels during treatment. Methodology/Principal Findings: Ultrasonography was applied for diagnosis and follow-up of CE cases after cyclic albendazole treatment in Tibetan communities of Sichuan Province during 2006 to 2008, and serum specific IgG antibody levels against Echinococcus granulosus recombinant antigen B in ELISA was concurrently monitored in these cases. A total of 196 CE cases were identified by ultrasound, of which 37 (18.9%) showed evidence of spontaneous healing/involution of hepatic cyst(s) with CE4 or CE5 presentations. Of 49 enrolled CE cases for treatment follow-up, 32.7% (16) were considered to be cured based on B-ultrasound after 6 months to 30 months regular albendazole treatment, 49.0% (24) were improved, 14.3% (7) remained unchanged, and 4.1% (2) became aggravated. In general, patients with CE2 type cysts (daughter cysts present) needed a longer treatment course for cure (26.4 months), compared to cases with CE1 (univesicular cysts) (20.4 months) or CE3 type (detached cyst membrane or partial degeneration of daughter cysts) (9 months). In addition, the curative duration was longer in patients with large (.10 cm) cysts (22.3 months), compared to cases with medium (5– 10 cm) cysts (17.3 months) or patients with small (,5 cm) cysts (6 months). At diagnosis, seven (53.8%) of 13 cases with CE1 type cysts without any previous intervention showed negative specific IgG antibody response to E. granulosus recombinant antigen B (rAgB). However, following 3 months to 18 months albendazole therapy, six of these 7 initially seronegative CE1 cases sero-converted to be specific IgG antibody positive, and concurrently ultrasound scan showed that cysts changed to CE3a from CE1 type in all the six CE cases. Two major profiles of serum specific IgG antibody dynamics during albendazole treatment were apparent in CE cases: (i) presenting as initial elevation followed by subsequent decline, or (ii) a persistent decline. Despite a decline, however, specific antibody levels remained positive in most improved or cured CE cases. Conclusions: This was the first attempt to follow up community-screened cystic echinococcosis patients after albendazole therapy using ultrasonography and serology in an endemic Tibetan region. Cyclic albendazole treatment proved to be effective in the great majority of CE cases in this resource-poor area, but periodic abdominal ultrasound examination was necessary to guide appropriate treatment. Oral albendazole for over 18 months was more likely to result in CE cure. Poor drug compliance resulted in less good outcomes. Serology with recombinant antigen B could provide additional limited information about the effectiveness of albendazole in CE cases. Post-treatment positive specific IgG antibody seroconversion, in initially seronegative, CE1 patients was considered a good indication for positive therapeutic efficacy of albendazole

    Public health risks associated with food‐borne parasites

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    Parasites are important food-borne pathogens. Their complex lifecycles, varied transmission routes, and prolonged periods between infection and symptoms mean that the public health burden and relative importance of different transmission routes are often difficult to assess. Furthermore, there are challenges in detection and diagnostics, and variations in reporting. A Europe-focused ranking exercise, using multicriteria decision analysis, identified potentially food-borne parasites of importance, and that are currently not routinely controlled in food. These are Cryptosporidium spp., Toxoplasma gondii and Echinococcus spp. Infection with these parasites in humans and animals, or their occurrence in food, is not notifiable in all Member States. This Opinion reviews current methods for detection, identification and tracing of these parasites in relevant foods, reviews literature on food-borne pathways, examines information on their occurrence and persistence in foods, and investigates possible control measures along the food chain. The differences between these three parasites are substantial, but for all there is a paucity of well-established, standardised, validated methods that can be applied across the range of relevant foods. Furthermore, the prolonged period between infection and clinical symptoms (from several days for Cryptosporidium to years for Echinococcus spp.) means that source attribution studies are very difficult. Nevertheless, our knowledge of the domestic animal lifecycle (involving dogs and livestock) for Echinoccocus granulosus means that this parasite is controllable. For Echinococcus multilocularis, for which the lifecycle involves wildlife (foxes and rodents), control would be expensive and complicated, but could be achieved in targeted areas with sufficient commitment and resources. Quantitative risk assessments have been described for Toxoplasma in meat. However, for T.gondii and Cryptosporidium as faecal contaminants, development of validated detection methods, including survival/infectivity assays and consensus molecular typing protocols, are required for the development of quantitative risk assessments and efficient control measures
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