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Sample records for modelling bse trend

  1. Modelling BSE trend over time in Europe, a risk assessment perspective

    NARCIS (Netherlands)

    Ducrot, C.; Sala, C.; Ru, G.; Koeijer, de A.A.; Sheridan, H.; Saegerman, C.; Selhorst, T.; Arnold, M.; Polak, M.P.; Calavas, D.

    2010-01-01

    BSE is a zoonotic disease that caused the emergence of variant Creuzfeldt-Jakob disease in the mid 1990s. The trend of the BSE epidemic in seven European countries was assessed and compared, using Age-Period-Cohort and Reproduction Ratio modelling applied to surveillance data 2001-2007. A strong dec

  2. Modelling BSE trend over time in Europe, a risk assessment perspective

    NARCIS (Netherlands)

    Ducrot, C.; Sala, C.; Ru, G.; Koeijer, de A.A.; Sheridan, H.; Saegerman, C.; Selhorst, T.; Arnold, M.; Polak, M.P.; Calavas, D.

    2010-01-01

    BSE is a zoonotic disease that caused the emergence of variant Creuzfeldt-Jakob disease in the mid 1990s. The trend of the BSE epidemic in seven European countries was assessed and compared, using Age-Period-Cohort and Reproduction Ratio modelling applied to surveillance data 2001-2007. A strong

  3. Modelling BSE trend over time in Europe, a risk assessment perspective.

    Science.gov (United States)

    Ducrot, Christian; Sala, Carole; Ru, Giuseppe; de Koeijer, Aline; Sheridan, Hazel; Saegerman, Claude; Selhorst, Thomas; Arnold, Mark; Polak, Miroslaw P; Calavas, Didier

    2010-06-01

    BSE is a zoonotic disease that caused the emergence of variant Creuzfeldt-Jakob disease in the mid 1990s. The trend of the BSE epidemic in seven European countries was assessed and compared, using Age-Period-Cohort and Reproduction Ratio modelling applied to surveillance data 2001-2007. A strong decline in BSE risk was observed for all countries that applied control measures during the 1990s, starting at different points in time in the different countries. Results were compared with the type and date of the BSE control measures implemented between 1990 and 2001 in each country. Results show that a ban on the feeding of meat and bone meal (MBM) to cattle alone was not sufficient to eliminate BSE. The fading out of the epidemic started shortly after the complementary measures targeted at controlling the risk in MBM. Given the long incubation period, it is still too early to estimate the additional effect of the ban on the feeding of animal protein to all farm animals that started in 2001. These results provide new insights in the risk assessment of BSE for cattle and Humans, which will especially be useful in the context of possible relaxing BSE surveillance and control measures.

  4. [Model calculation to explain the BSE-incidence in Germany].

    Science.gov (United States)

    Oberthür, Radulf C

    2004-01-01

    The future development of BSE-incidence in Germany is investigated using a simple epidemiological model calculation. Starting point is the development of the incidence of confirmed suspect BSE-cases in Great Britain since 1988, the hitherto known mechanisms of transmission and the measures taken to decrease the risk of transmission as well as the development of the BSE-incidence in Germany obtained from active post mortem laboratory testing of all cattle older then 24 months. The risk of transmission is characterized by the reproduction ratio of the disease. There is a shift in time between the risk of BSE transmission and the BSE incidence caused by the incubation time of more than 4 years. The observed decrease of the incidence in Germany from 2001 to 2003 is not a consequence of the measures taken at the end of 2000 to contain the disease. It can rather be explained by an import of BSE contaminated products from countries with a high BSE incidence in the years 1995/96 being used in calf feeding in Germany. From the future course of the BSE-incidence in Germany after 2003 a quantification of the recycling rate of BSE-infected material within Germany before the end of 2000 will be possible by use of the proposed model if the active surveillance is continued.

  5. Mathematical Models for Estimating the Risks of Bovine Spongiform Encephalopathy (BSE).

    Science.gov (United States)

    Al-Zoughool, Mustafa; Cottrell, David; Elsaadany, Susie; Murray, Noel; Oraby, Tamer; Smith, Robert; Krewski, Daniel

    2015-01-01

    When the bovine spongiform encephalopathy (BSE) epidemic first emerged in the United Kingdom in the mid 1980s, the etiology of animal prion diseases was largely unknown. Risk management efforts to control the disease were also subject to uncertainties regarding the extent of BSE infections and future course of the epidemic. As understanding of BSE increased, mathematical models were developed to estimate risk of BSE infection and to predict reductions in risk in response to BSE control measures. Risk models of BSE-transmission dynamics determined disease persistence in cattle herds and relative infectivity of cattle prior to onset of clinical disease. These BSE models helped in understanding key epidemiological features of BSE transmission and dynamics, such as incubation period distribution and age-dependent infection susceptibility to infection with the BSE agent. This review summarizes different mathematical models and methods that have been used to estimate risk of BSE, and discusses how such risk projection models have informed risk assessment and management of BSE. This review also provides some general insights on how mathematical models of the type discussed here may be used to estimate risks of emerging zoonotic diseases when biological data on transmission of the etiological agent are limited.

  6. Monitoring and analysis of bovine spongiform encephalopathy (BSE) testing in Denmark using statistical models

    DEFF Research Database (Denmark)

    Paisley, Larry

    2002-01-01

    The evolution of monitoring and surveillance for bovine spongiform encephalopathy (BSE) from the phase of passive surveillance that began in the United Kingdom in 1988 until the present is described. Currently, surveillance for BSE in Europe consists of mass testing of cattle slaughtered for human...

  7. Estimating the trend of the French BSE epidemic over six birth cohorts through the analysis of abattoir screening in 2001 and 2002.

    Science.gov (United States)

    La Bonnardière, Claude; Calavas, Didier; Abrial, David; Morignat, Eric; Ducrot, Christian

    2004-01-01

    A bovine spongiform encephalopathy (BSE) testing programme at the abattoir started in 2001 in France. A total of 5 281 293 bovines were tested in 2001 and 2002; 87 were found positive in 2001--37 per million (95% CI 30-46)--, whereas only 71 in 2002--24 per million (95% CI 19-30). Logistic regression models were run to compare the prevalence of BSE on successive birth cohorts, using a pair-wise method of controlling for age at testing; the prevalence on the first one, determined on animals slaughtered in 2001, was compared to the prevalence on the following one determined on animals slaughtered in 2002. Five models were performed in order to compare the birth cohorts preceding and following the months of June 1993 (i.e. July 92-June 93 birth cohort compared to July 93-June 94 birth cohort) (8.5 years old cattle), June 1994 (7.5 years old cattle), June 1995 (6.5 years old cattle), June 1996 (5.5 years old cattle) and June 1997 (4.5 years old cattle). The models were adjusted for the production type of cattle and the test used. The results showed a significant increase (OR = 2.31, 95% CI 1.08-4.9) of the BSE prevalence between the July 93-June 94 and July 94-June 95 cohorts, and then a significant decrease over the next two birth cohorts; the July 95-June 96 birth cohort was significantly less affected than the July 94-June 95 one (OR = 0.46, 95% CI 0.27-0.78), and the July 96-June 97 birth cohort was significantly less affected than the July 95-June 96 one (OR = 0.17, 95% CI 0.07-0.37). The increase in BSE prevalence between the July 93-June 94 and July 94-June 95 cohorts was in agreement with modelling studies, but needs to be confronted to the data on fallen stock at the national level. The decrease in BSE prevalence on the birth cohorts born after June 1995 was in agreement with the findings on the fallen stock in the western part of France and matches the implementation of the removal of specified risk materials (SRM) and dead animals from the processing of meat

  8. Price transmission in the Spanish bovine sector: the BSE effect

    OpenAIRE

    2010-01-01

    A regime-switching vector error correction model is applied to monthly price data to assess the impact of BSE outbreaks on price relationships and patterns of transmission among farm and retail markets for bovine in Spain. To evaluate the degree to which price transmission is affected by BSE food scares, a BSE food scare index is developed and used to determine regime-switching. Results suggest that BSE scares affect beef producers and retailers differently. Consumer prices are found to be we...

  9. BSE in the UK

    DEFF Research Database (Denmark)

    Jensen, Karsten Klint

    2004-01-01

    The 2000 BSE Inquiry report points out that the most serious failure of the UK Government was one of risk communication. This paper argues that the government's failure to communicate the risks BSE posed to humans to a large degree can be traced back to a lack of transparency in the first risk...

  10. Review on the epidemiology and dynamics of BSE epidemics.

    Science.gov (United States)

    Ducrot, Christian; Arnold, Mark; de Koeijer, Aline; Heim, Dagmar; Calavas, Didier

    2008-01-01

    The paper describes how the comprehensive surveillance of bovine spongiform encephalopathy (BSE) and studies carried out on these data has enhanced our knowledge of the epidemiology of BSE. Around 7, 000 BSE cases were detected through the screening of about 50 million cattle with rapid tests in Europe. It confirmed that the clinical surveillance had a poor capacity to detect cases, and also showed the discrepancy of this passive surveillance efficiency between regions and production types (dairy/beef). Other risk factors for BSE were being in a dairy herd (three times more than beef), having a young age at first calving (for dairy cattle), being autumn-born (dairy and beef), and being in a herd with a very high milk yield. These findings focus the risk on the feeding regimen of calves/heifers. Several epidemiological studies across countries suggest that the feedborne source related to meat and bone meal (MBM) is the only substantiated route of infection - even after the feed ban -, while it is not possible to exclude maternal transmission or milk replacers as a source of some infections. In most European countries, the average age of the cases is increasing over time and the prevalence decreasing, which reflects the effectiveness of control measures. Consistent results on the trend of the epidemic were obtained using back-calculation modelling, the R(0) approach and Age-Period-Cohort models. Furthermore, active surveillance also resulted in the finding of atypical cases. These are distinct from previously found BSE and classified in two different forms based on biochemical characteristics; their prevalence is very low (36 cases up to 1st September 2007), affected animals were old and some of them displayed clinical signs. The origin and possibility of natural transmission is unknown.

  11. Japan's BSE program

    Science.gov (United States)

    Imai, N.; Matsushita, M.; Kajikawa, M.

    1982-12-01

    An overview of the program for Japan's Medium-scale Broadcasting Satellite for Experimental Purpose (BSE), placed in orbit in 1978, is presented. The BSE was developed in order to provide useful technical data for establishing the fundamental technology of satellite broadcasting systems, the controlling and operational techniques of the broadcasting satellite, and the reception of broadcasting satellite radio waves. The satellite system and the ground facilities are discussed, and tables are included which list the system parameters and subsystems of the BSE. In addition, an outline is presented of the various experiments conducted utilizing the BSE, including the evaluation of the broadcasting service area, the transmission methods and their characteristics, controlling technique of the satellite, multiple access from different stations, and the improvement of receiving systems

  12. Emergence of classical BSE strain properties during serial passages of H-BSE in wild-type mice.

    Directory of Open Access Journals (Sweden)

    Thierry Baron

    Full Text Available BACKGROUND: Two distinct forms of atypical spongiform encephalopathies (H-BSE and L-BSE have recently been identified in cattle. Transmission studies in several wild-type or transgenic mouse models showed that these forms were associated with two distinct major strains of infectious agents, which also differed from the unique strain that had been isolated from cases of classical BSE during the food-borne epizootic disease. METHODOLOGY/PRINCIPAL FINDINGS: H-BSE was monitored during three serial passages in C57BL/6 mice. On second passage, most of the inoculated mice showed molecular features of the abnormal prion protein (PrP(d and brain lesions similar to those observed at first passage, but clearly distinct from those of classical BSE in this mouse model. These features were similarly maintained during a third passage. However, on second passage, some of the mice exhibited distinctly different molecular and lesion characteristics, reminiscent of classical BSE in C57Bl/6 mice. These similarities were confirmed on third passage from such mice, for which the same survival time was also observed as with classical BSE adapted to C57Bl/6 mice. Lymphotropism was rarely detected in mice with H-BSE features. In contrast, PrP(d was detectable, on third passage, in the spleens of most mice exhibiting classical BSE features, the pattern being indistinguishable from that found in C57Bl/6 mice infected with classical BSE. CONCLUSION/SIGNIFICANCE: Our data demonstrate the emergence of a prion strain with features similar to classical BSE during serial passages of H-BSE in wild-type mice. Such findings might help to explain the origin of the classical BSE epizootic disease, which could have originated from a putatively sporadic form of BSE.

  13. Transmission characteristics of BSE transponder

    Science.gov (United States)

    Yamamoto, M.; Fukuchi, H.; Kozu, T.; Igarashi, M.; Takeuchi, M.

    1986-01-01

    The transmission characteristics of the BSE transponder and their variation with the passage of time measured during the period from the beginning of BSE operation, May 1978 to March 1979, were previously reported. In this paper, the subsequent investigation completed by the time of the failure of the last high power amplifier of 100 watts of the BSE, June 1980, is discussed.

  14. Minder BSE en scrapie

    NARCIS (Netherlands)

    Zijderveld, van F.G.

    2011-01-01

    De dierziekte BSE is gevaarlijk voor de mens. Onderzoekers van het Central Veterinary Institute (CVI) hebben daarom snelle diagnostische tests ontwikkeld en ingezet bij rundvee, schapen en geiten. Ook hebben ze ervoor gezorgd dat schapen minder vatbaar zijn voor de verwante prionziekte scrapie.

  15. Late stage cathepsin C, CXCL13 and Ki-67 overexpression correlate with regional neuropathology in a BSE transgenic murine model.

    Science.gov (United States)

    Vidal, E; Tortosa, R; Marco, P; Fondevila, D; Rabanal, R M; Torres, J M; Pumarola, M

    2013-01-01

    A DNA microarray-based gene expression analysis study was performed with bovine spongiform encephalopathy (BSE) transgenic mice. Several genes were found to be overexpressed including the lysosomal enzyme cathepsin C, the chemokine CXCL13 and a number of genes related to cellular proliferation. The brains from terminal stage, BSE inoculated, 'bovinized', transgenic mice were subjected to immunohistochemistry with antibodies against these two proteins and Ki-67, a cell proliferation marker, to assess the biological relevance of the gene expression changes. Differential expression of cathepsin C and CXCL13 proteins and increased expression of Ki-67 was observed. These changes were localized to areas of deposition of PrP(res) and spongiform change and to areas showing an astroglial and microglial response. These findings suggest that these proteins are involved in the mechanisms leading to the establishment of transmissible spongiform encephalopathy.

  16. Resistance of bovine spongiform encephalopathy (BSE prions to inactivation.

    Directory of Open Access Journals (Sweden)

    Kurt Giles

    2008-11-01

    Full Text Available Distinct prion strains often exhibit different incubation periods and patterns of neuropathological lesions. Strain characteristics are generally retained upon intraspecies transmission, but may change on transmission to another species. We investigated the inactivation of two related prions strains: BSE prions from cattle and mouse-passaged BSE prions, termed 301V. Inactivation was manipulated by exposure to sodium dodecyl sulfate (SDS, variations in pH, and different temperatures. Infectivity was measured using transgenic mouse lines that are highly susceptible to either BSE or 301V prions. Bioassays demonstrated that BSE prions are up to 1,000-fold more resistant to inactivation than 301V prions while Western immunoblotting showed that short acidic SDS treatments reduced protease-resistant PrP(Sc from BSE prions and 301V prions at similar rates. Our findings argue that despite being derived from BSE prions, mouse 301V prions are not necessarily a reliable model for cattle BSE prions. Extending these comparisons to human sporadic Creutzfeldt-Jakob disease and hamster Sc237 prions, we found that BSE prions were 10- and 10(6-fold more resistant to inactivation, respectively. Our studies contend that any prion inactivation procedures must be validated by bioassay against the prion strain for which they are intended to be used.

  17. Resistance of bovine spongiform encephalopathy (BSE) prions to inactivation.

    Science.gov (United States)

    Giles, Kurt; Glidden, David V; Beckwith, Robyn; Seoanes, Rose; Peretz, David; DeArmond, Stephen J; Prusiner, Stanley B

    2008-11-01

    Distinct prion strains often exhibit different incubation periods and patterns of neuropathological lesions. Strain characteristics are generally retained upon intraspecies transmission, but may change on transmission to another species. We investigated the inactivation of two related prions strains: BSE prions from cattle and mouse-passaged BSE prions, termed 301V. Inactivation was manipulated by exposure to sodium dodecyl sulfate (SDS), variations in pH, and different temperatures. Infectivity was measured using transgenic mouse lines that are highly susceptible to either BSE or 301V prions. Bioassays demonstrated that BSE prions are up to 1,000-fold more resistant to inactivation than 301V prions while Western immunoblotting showed that short acidic SDS treatments reduced protease-resistant PrP(Sc) from BSE prions and 301V prions at similar rates. Our findings argue that despite being derived from BSE prions, mouse 301V prions are not necessarily a reliable model for cattle BSE prions. Extending these comparisons to human sporadic Creutzfeldt-Jakob disease and hamster Sc237 prions, we found that BSE prions were 10- and 10(6)-fold more resistant to inactivation, respectively. Our studies contend that any prion inactivation procedures must be validated by bioassay against the prion strain for which they are intended to be used.

  18. Effectiveness of the BSE interventions in Japan

    NARCIS (Netherlands)

    Sugiura, K.; Benedictus, A.; Hogeveen, H.

    2014-01-01

    Using a stochastic simulation model, we estimated the effectiveness of the three BSE interventions (SRM removal, post-mortem testing and cohort culling) in Japan, in terms of the amount of bovine ID50 that would be prevented from entering the human food supply and the number of life years that would

  19. Scientific Opinion on BSE risk in bovine intestines and mesentery

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Biological Hazards (BIOHAZ

    2014-02-01

    Full Text Available Bovine intestines and mesenteries in the European Union (EU have to be removed from the food and feed chain. The opinion provides a quantitative assessment of the Bovine Spongiform Encephalopathy (BSE infectious load that might enter the food and feed chain yearly if bovine intestine and mesentery from animals born and raised in the EU would be re-allowed for consumption. Data on the evolution of the BSE infectious titre; and of the weight of histological structures accumulating BSE infectivity, were collected. The Cattle TSE Monitoring Model (C-TSEMM was used to estimate the number of BSE infected cattle entering undetected in the food and feed chain yearly. A model named TSEi was developed to estimates the BSE infectious load in tissues from infected animals at different ages and the total yearly infectious load that could enter the food and feed chain in the EU27. In BSE infected cattle, the infectivity associated with intestine and mesentery reaches its maximum in animals younger than 18 months and then progressively declines to a minimum value in animals older than 60 months. Due to the decline of the BSE prevalence in the EU, between 2007 and 2012, the yearly amount of BSE infectivity associated with intestine and mesentery (sent to destruction from animals entering the food and feed chain was reduced by a factor of 10. However, over this period, the maximum level of exposure to the BSE agent for individuals that would have consumed these tissues remained stable. Finally, the TSEi model indicated that the removal of the last four metres of the small intestine and of the caecum from the food and feed chain would result in a major reduction of the BSE exposure risk associated with intestine and mesentery in cattle.

  20. Impact of BSE on livestock production system.

    Science.gov (United States)

    Nardone, A

    2003-09-01

    The small number of BSE cases diagnosed in Italy from January 2001 to 12 September 2001 (a total of 28, one every 9000 head) does not allow for a statistical analysis of the relationship between this disease and the livestock systems. However, some indications can be noted: (a) only dairy cattle, which represent three-quarters of the cattle raised in Italy, are involved; (b) 58% of the cases belong to medium-large farms that breed 27% of all head; (c) 13 out of 28 cases are 5-year-old animals and 26 out of 28 are between 5 and 7 years of age; (d) 15 of 28 cases come from Lombardia, where 27% of Italian dairy cattle are raised. The following factors may have affected the livestock system: (1) trends of beef meat consumption; (2) changes in livestock management; (3) changes in animal feeding; (4) possible effects on selection. A strong decline in beef meat consumption (4 kg/year) has been observed in the UK and other European countries since 1996 (the year of the discovery of the relationship between BSE and nvCJD). In Italy, from January 2001 the consumption of beef meat has declined as well as slaughter: a drop of 31% in the total slaughtered head in the period January-February, a drop of 14% in January-May. A fall in the price of calves has promoted, in some dairy farms, the start of the production of light beef less than one year old (advantages in the marketing of meat favour this initiative), a phenomenon which is not yet well established. Traceability and certification of meat have improved, thanks to breeders' associations and interprofessional agreements. The breeders associations have also started insurance initiatives against BSE risks. In Italy the employment of plant protein meals would increase the total feedstuff consumption by about 7%. Direct effects of BSE could slow down the genetic progress (GP) of cattle populations within breed and country. Indirect effects on GP may also happen as a consequence of an increase in the replacement rate (rr). This

  1. Transmission of BSE by blood transfusion in sheep.

    Science.gov (United States)

    Houston, F; Foster, J D; Chong, A; Hunter, N; Bostock, C J

    2000-09-16

    We have shown that it is possible to transmit bovine spongiform encephalopathy (BSE) to a sheep by transfusion with whole blood taken from another sheep during the symptom-free phase of an experimental BSE infection. BSE and variant Creutzfeldt-Jakob disease (vCJD) In human beings are caused by the same infectious agent, and the sheep-BSE experimental model has a similar pathogenesis to that of human vCJD. Although UK blood transfusions are leucodepleted--a possible protective measure against any risk from blood transmission--this report suggests that blood donated by symptom-free vCJD-infected human beings may represent a risk of spread of vCJD infection among the human population of the UK.

  2. The transmission dynamics of BSE and vCJD.

    Science.gov (United States)

    Ghani, Azra C; Donnelly, Christl A; Ferguson, Neil M; Anderson, Roy M

    2002-01-01

    The bovine spongiform encephalopathy (BSE) epidemic in cattle has had a huge economic impact on the agricultural industries across Europe. Furthermore, scientific evidence now strongly supporting a link between a new variant of Creutzfeldt-Jakob disease (vCJD) and consumption of BSE-infected animals has further heightened the need both to understand the transmission of these new diseases and to improve control measures to protect public health. In this paper we review work undertaken by our group using epidemiological models to understand the transmission dynamics of BSE and vCJD. We present new estimates of the future number of cases of BSE and the number of infected animals slaughtered for consumption for Great Britain, and summarise similar analyses undertaken for Northern Ireland, Ireland, Portugal and France. We also consider the epidemiological determinants of the future course of the vCJD epidemic, including the age and genetic characteristics of the confirmed cases, and present predictions of future case numbers.

  3. Descriptive spatial analysis of BSE in western France.

    Science.gov (United States)

    Abrial, David; Calavas, Didier; Lauvergne, Nathalie; Morignat, Eric; Ducrot, Christian

    2003-01-01

    The spatial heterogeneity of Bovine Spongiform Encephalopathy (BSE) was analysed on the 84 cases confirmed in western France (WF) between August and December 2000, when both the Mandatory Reporting System and an active surveillance on cattle at risk were running. Ninety-four percent of these cases were born between June 1993 and June 1996, and we analysed the location at birth. One disease mapping and two clustering methods (Scan of Kulldorff and the method of Besag and Newell) were used. In order to attenuate the contrasts artificially created by the standard disease mapping method (over-dispersion), we estimated the Standard Incidence Ratio (SIR) with a Bayesian method (Poisson-Gamma model) allowing a smoothing of the estimators. The geographical location of interest was the "canton", that divided the total area into 526 geographical units. The background population (2.6 million cattle) was obtained from the Agricultural Census 2000. We tested the hypothesis of a homogenous spatial distribution of the BSE risk where the expected number of BSE cases per unit area was obtained by applying the overall BSE rate in WF to each "canton", standardised on the type of breed, dairy versus beef suckler. The SIR ranged from 0.80 to 2.18 and the spatial distribution of BSE cases was significantly heterogeneous. Two spatial clusters were detected with the spatial scan statistics of Kulldorff and the method of Besag and Newell (18 to 20 observed BSE-cases per cluster with a radius of 45 km) centred on the "département" of Côtes-d'Armor and Mayenne. Another cluster was detected with the method of Besag and Newell (9 observed BSE-cases) in the "département" of Finistère. The results proved that the risk of BSE is linked to the geographical location in the area of the study.

  4. EFSA BIOHAZ Panel (EFSA Panel on Biological Hazards), 2014. Scientific Opinion on BSE risk in bovine intestines and mesentery

    DEFF Research Database (Denmark)

    Hald, Tine; Baggesen, Dorte Lau

    and mesentery from animals born and raised in the EU would be re-allowed for consumption. Data on the evolution of the BSE infectious titre; and of the weight of histological structures accumulating BSE infectivity, were collected. The Cattle TSE Monitoring Model (C-TSEMM) was used to estimate the number of BSE...

  5. Analyzing BSE transmission to quantify regional risk.

    Science.gov (United States)

    de Koeijer, Aline A

    2007-10-01

    As a result of consumer fears and political concerns related to BSE as a risk to human health, a need has arisen recently for more sensitive methods to detect BSE and more accurate methods to determine BSE incidence. As a part of the development of such methods, it is important to be able to identify groups of animals with above-average BSE risk. One of the well-known risk factors for BSE is age, as very young animals do not develop the disease, and very old animals are less likely to develop the disease. Here, we analyze which factors have a strong influence on the age distribution of BSE in a population. Building on that, we develop a simple set of calculation rules for classifying the BSE risk in a given cattle population. Required inputs are data on imports and on the BSE control measures in place over the last 10 or 20 years.

  6. [Basic research on BSE transmission to people].

    Science.gov (United States)

    Bodemer, W; Kaup, F J

    2002-08-01

    Prion diseases of animal and man belong to neurological diseases with amyloidal deposition of the respective proteins. As to prion disease, the cellular prionprotein is in its abnormal isoform(s) an essential component of prionprotein aggregates found in affected tissue. In contrast to all neurodegenerative diseases like Morbus Alzheimer or Huntington's disease, prion diseases are transmissible. Therefore, prion diseases were designated Transmissible Spongiform Encephalopathies (TSE). The diseases are well known since decades. Scrapie was first described around 1750, a BSE case was reported in the 1850, most likely a misdiagnosis, and in 1920/1930 the human Creutzfeldt-Jakob disease (CJD) had been described. Transmission of CJD i.e. Kuru had been suspected in the early 1950s and erronously classified as slow virus disease. The CJD transmission posed a problem to humans when transplants from CJD cases were used for treatment. Fortunately, these iatrogenic transmissions remained limited. But with the advent of BSE and appearance of variant CJD cases in the UK and some places in Europe scientists suspected that transmission from cattle to man could have happened. From animal models we know of successful transmission via several routes. Species barriers do not completely prevent transmission. Rather transmission barriers might exist controlling individual susceptibility against prions. Modes of transmission, susceptibility for transmission, identification of receptor molecules as well as molecular mechanisms of the transmission process are intensely investigated. Current knowledge let us to assume that inapparent stages of prion infection pretend a (not existing) species barrier. This inapparent infection preceeds overt disease and, thus, most re-search focuses on the development of highly sensitive assay systems for detection of minute amounts of pathological prionprotein in suspected cases. Inapparence also should warn us to underestimate BSE or human vCJD cases; at

  7. Analysing BSE transmission fo quantify regional risk

    NARCIS (Netherlands)

    Koeijer, de A.A.

    2007-01-01

    As a result of consumer fears and political concerns related to BSE as a risk to human health, a need has arisen recently for more sensitive methods to detect BSE and more accurate methods to determine BSE incidence. As a part of the development of such methods, it is important to be able to identif

  8. Epidemiological implications of the susceptibility to BSE of putatively resistant sheep.

    Science.gov (United States)

    Kao, R R; Houston, F; Baylis, M; Chihota, C M; Goldmann, W; Gravenor, M B; Hunter, N; McLean, A R

    2003-12-01

    The experimental infection of sheep with bovine spongiform encephalopathy (BSE) by the oral route and the likelihood that sheep were fed BSE-infected meat and bone meal has led to extensive speculation as to whether or not sheep are naturally infected with BSE. In response, the UK government has initiated the National Scrapie Plan (NSP), an ambitious pound 120 million per year project to create a BSE- and scrapie-resistant national sheep flock, by selectively breeding for a genotype of sheep believed to be resistant to both diseases. This genotype has recently been shown to be susceptible to BSE by intracerebral (i.c.) inoculation. Should these sheep be sufficiently susceptible to BSE via natural transmission, the NSP might fail. Here we estimate the susceptibility of this genotype to horizontal (sheep-to-sheep) transmission of BSE by comparison with more extensive oral and i.c. exposure data for other sheep genotypes. We show that a previous estimate of the risk of BSE transmission to sheep via the feedborne route remains robust. However, using a mathematical model for the within-flock transmission of BSE, we show that, while the best estimate indicates that the NSP should be successful, current data cannot exclude the failure of the NSP.

  9. Results of the BSE experiment

    Science.gov (United States)

    Iwasaki, K.; Yamamoto, M.; Kurakake, Y.; Kinoshita, S.

    Results of satellite broadcasting experiments carried out using the BSE (Japan's Medium-scale Broadcasting Satellite for Experimental Purpose) are described. Consideration is given to the following experiments: the reception of radio waves from the satellite, radio wave attenuation and scattering, the uplink power control experiment, experiments with transportable earth stations, the transmission of FM-TV signals, and frequency sharing between the broadcasting satellite and broadcasting services in the 12 GHz band.

  10. Comparison of the historic recycling risk for BSE in three European Countries by calculating RO.

    NARCIS (Netherlands)

    Schwermer, H.; Koeijer, de A.A.; Brülisauer, F.; Heim, D.

    2007-01-01

    Adeterministic model of BSE transmission is used to calculate the R0 values for specific years of the BSE epidemics in the United Kingdom (UK), the Netherlands (NL), and Switzerland (CH). In all three countries, theR0 values decreased below 1 after the introduction of a ban on feeding meat and bone

  11. Evacuation modeling trends

    CERN Document Server

    Abreu, Orlando; Alvear, Daniel

    2016-01-01

    This book presents an overview of modeling definitions and concepts, theory on human behavior and human performance data, available tools and simulation approaches, model development, and application and validation methods. It considers the data and research efforts needed to develop and incorporate functions for the different parameters into comprehensive escape and evacuation simulations, with a number of examples illustrating different aspects and approaches. After an overview of basic modeling approaches, the book discusses benefits and challenges of current techniques. The representation of evacuees is a central issue, including human behavior and the proper implementation of representational tools. Key topics include the nature and importance of the different parameters involved in ASET and RSET and the interactions between them. A review of the current literature on verification and validation methods is provided, with a set of recommended verification tests and examples of validation tests. The book c...

  12. Maternal transmission studies of BSE in sheep.

    Science.gov (United States)

    Foster, J D; Goldmann, W; McKenzie, C; Smith, A; Parnham, D W; Hunter, N

    2004-10-01

    If BSE (bovine spongiform encephalopathy) infected the UK sheep population concurrently with cattle, it would only now be maintained by transmission between sheep by routes which could include from mother to lamb either in utero or via perinatal close contact. In this study of experimental BSE, Cheviot ewes challenged orally with BSE cattle brain produced lambs of various PrP genotypes over the next 7 years. Of 72 surviving to >30 months of age, 29 are of the most susceptible PrP genotype (AQ/AQ) and born to mothers that were challenged with BSE. None of the progeny have shown any signs of disease. The results suggest that in these sheep, BSE could only transmit by the maternal route at a frequency of less than one in four (95 % confidence limit) from clinically affected ewes, a rate which if replicated in other breeds may not be sufficient to maintain BSE within the sheep population.

  13. Preclinical detection of variant CJD and BSE prions in blood.

    Science.gov (United States)

    Lacroux, Caroline; Comoy, Emmanuel; Moudjou, Mohammed; Perret-Liaudet, Armand; Lugan, Séverine; Litaise, Claire; Simmons, Hugh; Jas-Duval, Christelle; Lantier, Isabelle; Béringue, Vincent; Groschup, Martin; Fichet, Guillaume; Costes, Pierrette; Streichenberger, Nathalie; Lantier, Frederic; Deslys, Jean Philippe; Vilette, Didier; Andréoletti, Olivier

    2014-06-01

    The emergence of variant Creutzfeldt Jakob Disease (vCJD) is considered a likely consequence of human dietary exposure to Bovine Spongiform Encephalopathy (BSE) agent. More recently, secondary vCJD cases were identified in patients transfused with blood products prepared from apparently healthy donors who later went on to develop the disease. As there is no validated assay for detection of vCJD/BSE infected individuals the prevalence of the disease in the population remains uncertain. In that context, the risk of vCJD blood borne transmission is considered as a serious concern by health authorities. In this study, appropriate conditions and substrates for highly efficient and specific in vitro amplification of vCJD/BSE agent using Protein Misfolding Cyclic Amplification (PMCA) were first identified. This showed that whatever the origin (species) of the vCJD/BSE agent, the ovine Q171 PrP substrates provided the best amplification performances. These results indicate that the homology of PrP amino-acid sequence between the seed and the substrate is not the crucial determinant of the vCJD agent propagation in vitro. The ability of this method to detect endogenous vCJD/BSE agent in the blood was then defined. In both sheep and primate models of the disease, the assay enabled the identification of infected individuals in the early preclinical stage of the incubation period. Finally, sample panels that included buffy coat from vCJD affected patients and healthy controls were tested blind. The assay identified three out of the four tested vCJD affected patients and no false positive was observed in 141 healthy controls. The negative results observed in one of the tested vCJD cases concurs with results reported by others using a different vCJD agent blood detection assay and raises the question of the potential absence of prionemia in certain patients.

  14. Preclinical detection of variant CJD and BSE prions in blood.

    Directory of Open Access Journals (Sweden)

    Caroline Lacroux

    2014-06-01

    Full Text Available The emergence of variant Creutzfeldt Jakob Disease (vCJD is considered a likely consequence of human dietary exposure to Bovine Spongiform Encephalopathy (BSE agent. More recently, secondary vCJD cases were identified in patients transfused with blood products prepared from apparently healthy donors who later went on to develop the disease. As there is no validated assay for detection of vCJD/BSE infected individuals the prevalence of the disease in the population remains uncertain. In that context, the risk of vCJD blood borne transmission is considered as a serious concern by health authorities. In this study, appropriate conditions and substrates for highly efficient and specific in vitro amplification of vCJD/BSE agent using Protein Misfolding Cyclic Amplification (PMCA were first identified. This showed that whatever the origin (species of the vCJD/BSE agent, the ovine Q171 PrP substrates provided the best amplification performances. These results indicate that the homology of PrP amino-acid sequence between the seed and the substrate is not the crucial determinant of the vCJD agent propagation in vitro. The ability of this method to detect endogenous vCJD/BSE agent in the blood was then defined. In both sheep and primate models of the disease, the assay enabled the identification of infected individuals in the early preclinical stage of the incubation period. Finally, sample panels that included buffy coat from vCJD affected patients and healthy controls were tested blind. The assay identified three out of the four tested vCJD affected patients and no false positive was observed in 141 healthy controls. The negative results observed in one of the tested vCJD cases concurs with results reported by others using a different vCJD agent blood detection assay and raises the question of the potential absence of prionemia in certain patients.

  15. Changing Trends in Modeling Mobility

    Directory of Open Access Journals (Sweden)

    Aarti Munjal

    2012-01-01

    Full Text Available A phenomenal increase in the number of wireless devices has led to the evolution of several interesting and challenging research problems in opportunistic networks. For example, the random waypoint mobility model, an early, popular effort to model mobility, involves generating random movement patterns. Previous research efforts, however, validate that movement patterns are not random; instead, human mobility is predictable to some extent. Since the performance of a routing protocol in an opportunistic network is greatly improved if the movement patterns of mobile users can be somewhat predicted in advance, several research attempts have been made to understand human mobility. The solutions developed use our understanding of movement patterns to predict the future contact probability for mobile nodes. In this work, we summarize the changing trends in modeling human mobility as random movements to the current research efforts that model human walks in a more predictable manner. Mobility patterns significantly affect the performance of a routing protocol. Thus, the changing trend in modeling mobility has led to several changes in developing routing protocols for opportunistic networks. For example, the simplest opportunistic routing protocol forwards a received packet to a randomly selected neighbor. With predictable mobility, however, routing protocols can use the expected contact information between a pair of mobile nodes in making forwarding decisions. In this work, we also describe the previous and current research efforts in developing routing protocols for opportunistic networks.

  16. Conversion of the BASE prion strain into the BSE strain: the origin of BSE?

    Science.gov (United States)

    Capobianco, Raffaella; Casalone, Cristina; Suardi, Silvia; Mangieri, Michela; Miccolo, Claudia; Limido, Lucia; Catania, Marcella; Rossi, Giacomina; Di Fede, Giuseppe; Giaccone, Giorgio; Bruzzone, Maria Grazia; Minati, Ludovico; Corona, Cristiano; Acutis, Pierluigi; Gelmetti, Daniela; Lombardi, Guerino; Groschup, Martin H; Buschmann, Anne; Zanusso, Gianluigi; Monaco, Salvatore; Caramelli, Maria; Tagliavini, Fabrizio

    2007-03-01

    Atypical neuropathological and molecular phenotypes of bovine spongiform encephalopathy (BSE) have recently been identified in different countries. One of these phenotypes, named bovine "amyloidotic" spongiform encephalopathy (BASE), differs from classical BSE for the occurrence of a distinct type of the disease-associated prion protein (PrP), termed PrP(Sc), and the presence of PrP amyloid plaques. Here, we show that the agents responsible for BSE and BASE possess different biological properties upon transmission to transgenic mice expressing bovine PrP and inbred lines of nontransgenic mice. Strikingly, serial passages of the BASE strain to nontransgenic mice induced a neuropathological and molecular disease phenotype indistinguishable from that of BSE-infected mice. The existence of more than one agent associated with prion disease in cattle and the ability of the BASE strain to convert into the BSE strain may have important implications with respect to the origin of BSE and spongiform encephalopathies in other species, including humans.

  17. Relationship with BSE (Mad Cow Disease)

    Science.gov (United States)

    ... study involving inoculation of a panel of inbred mice with the agents causing BSE and vCJD substantially ... 498-501). In this study, groups of inbred mice and a group of cross-bred mice inoculated ...

  18. Emergence of a novel bovine spongiform encephalopathy (BSE) prion from an atypical H-type BSE.

    Science.gov (United States)

    Masujin, Kentaro; Okada, Hiroyuki; Miyazawa, Kohtaro; Matsuura, Yuichi; Imamura, Morikazu; Iwamaru, Yoshifumi; Murayama, Yuichi; Yokoyama, Takashi

    2016-03-07

    The H-type of atypical bovine spongiform encephalopathy (H-BSE) was serially passaged in bovinized transgenic (TgBoPrP) mice. At the fourth passage, most challenged mice showed a typical H-BSE phenotype with incubation periods of 223 ± 7.8 days. However, a different phenotype of BSE prion with shorter incubation periods of 109 ± 4 days emerged in a minor subset of the inoculated mice. The latter showed distinct clinical signs, brain pathology, and abnormal prion protein profiles as compared to H-BSE and other known BSE strains in mice. This novel prion was transmitted intracerebrally to cattle, with incubation periods of 14.8 ± 1.5 months, with phenotypes that differed from those of other bovine prion strains. These data suggest that intraspecies transmission of H-BSE in cattle allows the emergence of a novel BSE strain. Therefore, the continuation of feed ban programs may be necessary to exclude the recycling of H-BSE prions, which appear to arise spontaneously, in livestock. Such measures should help to reduce the risks from both novel and known strains of BSE.

  19. Evaluation of trends in wheat yield models

    Science.gov (United States)

    Ferguson, M. C.

    1982-01-01

    Trend terms in models for wheat yield in the U.S. Great Plains for the years 1932 to 1976 are evaluated. The subset of meteorological variables yielding the largest adjusted R(2) is selected using the method of leaps and bounds. Latent root regression is used to eliminate multicollinearities, and generalized ridge regression is used to introduce bias to provide stability in the data matrix. The regression model used provides for two trends in each of two models: a dependent model in which the trend line is piece-wise continuous, and an independent model in which the trend line is discontinuous at the year of the slope change. It was found that the trend lines best describing the wheat yields consisted of combinations of increasing, decreasing, and constant trend: four combinations for the dependent model and seven for the independent model.

  20. Atypical BSE (BASE transmitted from asymptomatic aging cattle to a primate.

    Directory of Open Access Journals (Sweden)

    Emmanuel E Comoy

    Full Text Available BACKGROUND: Human variant Creutzfeldt-Jakob Disease (vCJD results from foodborne transmission of prions from slaughtered cattle with classical Bovine Spongiform Encephalopathy (cBSE. Atypical forms of BSE, which remain mostly asymptomatic in aging cattle, were recently identified at slaughterhouses throughout Europe and North America, raising a question about human susceptibility to these new prion strains. METHODOLOGY/PRINCIPAL FINDINGS: Brain homogenates from cattle with classical BSE and atypical (BASE infections were inoculated intracerebrally into cynomolgus monkeys (Macacca fascicularis, a non-human primate model previously demonstrated to be susceptible to the original strain of cBSE. The resulting diseases were compared in terms of clinical signs, histology and biochemistry of the abnormal prion protein (PrPres. The single monkey infected with BASE had a shorter survival, and a different clinical evolution, histopathology, and prion protein (PrPres pattern than was observed for either classical BSE or vCJD-inoculated animals. Also, the biochemical signature of PrPres in the BASE-inoculated animal was found to have a higher proteinase K sensitivity of the octa-repeat region. We found the same biochemical signature in three of four human patients with sporadic CJD and an MM type 2 PrP genotype who lived in the same country as the infected bovine. CONCLUSION/SIGNIFICANCE: Our results point to a possibly higher degree of pathogenicity of BASE than classical BSE in primates and also raise a question about a possible link to one uncommon subset of cases of apparently sporadic CJD. Thus, despite the waning epidemic of classical BSE, the occurrence of atypical strains should temper the urge to relax measures currently in place to protect public health from accidental contamination by BSE-contaminated products.

  1. Estimating the human health risk from possible BSE infection of the British sheep flock.

    Science.gov (United States)

    Ferguson, N M; Ghani, A C; Donnelly, C A; Hagenaars, T J; Anderson, R M

    2002-01-24

    Following the controversial failure of a recent study and the small numbers of animals yet screened for infection, it remains uncertain whether bovine spongiform encephalopathy (BSE) was transmitted to sheep in the past via feed supplements and whether it is still present. Well grounded mathematical and statistical models are therefore essential to integrate the limited and disparate data, to explore uncertainty, and to define data-collection priorities. We analysed the implications of different scenarios of BSE spread in sheep for relative human exposure levels and variant Creutzfeldt-Jakob disease (vCJD) incidence. Here we show that, if BSE entered the sheep population and a degree of transmission occurred, then ongoing public health risks from ovine BSE are likely to be greater than those from cattle, but that any such risk could be reduced by up to 90% through additional restrictions on sheep products entering the food supply. Extending the analysis to consider absolute risk, we estimate the 95% confidence interval for future vCJD mortality to be 50 to 50,000 human deaths considering exposure to bovine BSE alone, with the upper bound increasing to 150,000 once we include exposure from the worst-case ovine BSE scenario examined.

  2. Generation of a persistently infected MDBK cell line with natural bovine spongiform encephalopathy (BSE.

    Directory of Open Access Journals (Sweden)

    Dongseob Tark

    Full Text Available Bovine spongiform encephalopathy (BSE is a zoonotic transmissible spongiform encephalopathy (TSE thought to be caused by the same prion strain as variant Creutzfeldt-Jakob disease (vCJD. Unlike scrapie and chronic wasting disease there is no cell culture model allowing the replication of proteinase K resistant BSE (PrPBSE and the further in vitro study of this disease. We have generated a cell line based on the Madin-Darby Bovine Kidney (MDBK cell line over-expressing the bovine prion protein. After exposure to naturally BSE-infected bovine brain homogenate this cell line has shown to replicate and accumulate PrPBSE and maintain infection up to passage 83 after initial challenge. Collectively, we demonstrate, for the first time, that the BSE agent can infect cell lines over-expressing the bovine prion protein similar to other prion diseases. These BSE infected cells will provide a useful tool to facilitate the study of potential therapeutic agents and the diagnosis of BSE.

  3. Generation of a persistently infected MDBK cell line with natural bovine spongiform encephalopathy (BSE).

    Science.gov (United States)

    Tark, Dongseob; Kim, Hyojin; Neale, Michael H; Kim, Minjeong; Sohn, Hyunjoo; Lee, Yoonhee; Cho, Insoo; Joo, Yiseok; Windl, Otto

    2015-01-01

    Bovine spongiform encephalopathy (BSE) is a zoonotic transmissible spongiform encephalopathy (TSE) thought to be caused by the same prion strain as variant Creutzfeldt-Jakob disease (vCJD). Unlike scrapie and chronic wasting disease there is no cell culture model allowing the replication of proteinase K resistant BSE (PrPBSE) and the further in vitro study of this disease. We have generated a cell line based on the Madin-Darby Bovine Kidney (MDBK) cell line over-expressing the bovine prion protein. After exposure to naturally BSE-infected bovine brain homogenate this cell line has shown to replicate and accumulate PrPBSE and maintain infection up to passage 83 after initial challenge. Collectively, we demonstrate, for the first time, that the BSE agent can infect cell lines over-expressing the bovine prion protein similar to other prion diseases. These BSE infected cells will provide a useful tool to facilitate the study of potential therapeutic agents and the diagnosis of BSE.

  4. Emergence of a novel bovine spongiform encephalopathy (BSE) prion from an atypical H-type BSE

    OpenAIRE

    2016-01-01

    The H-type of atypical bovine spongiform encephalopathy (H-BSE) was serially passaged in bovinized transgenic (TgBoPrP) mice. At the fourth passage, most challenged mice showed a typical H-BSE phenotype with incubation periods of 223 ± 7.8 days. However, a different phenotype of BSE prion with shorter incubation periods of 109 ± 4 days emerged in a minor subset of the inoculated mice. The latter showed distinct clinical signs, brain pathology, and abnormal prion protein profiles as compared t...

  5. Review on the epidemiology and dynamics of BSE epidemics

    NARCIS (Netherlands)

    Ducrot, C.; Calavas, D.; Arnold, M.; Koeijer, de A.A.; Heim, D.

    2008-01-01

    The paper describes how the comprehensive surveillance of bovine spongiform encephalopathy (BSE) and studies carried out on these data has enhanced our knowledge of the epidemiology of BSE. Around 7 000 BSE cases were detected through the screening of about 50 million cattle with rapid tests in Euro

  6. Does the Amazon suffer from BSE prevention?

    NARCIS (Netherlands)

    Elferink, E.V.; Nonhebel, S.; Schoot Uiterkamp, A.J.M.

    2007-01-01

    In the last decade, large-scale production of soybeans has been a major driver of the enhanced deforestation in the Brazilian Amazon. We show that these soybeans are mainly exported to the EU to substitute for the BSE related banned meat and bone meal in livestock feed. This strongly suggests a link

  7. Does the Amazon suffer from BSE prevention?

    NARCIS (Netherlands)

    Elferink, E.V.; Nonhebel, S.; Schoot Uiterkamp, A.J.M.

    2007-01-01

    In the last decade, large-scale production of soybeans has been a major driver of the enhanced deforestation in the Brazilian Amazon. We show that these soybeans are mainly exported to the EU to substitute for the BSE related banned meat and bone meal in livestock feed. This strongly suggests a link

  8. Risks from BSE: via environmental pathways

    Energy Technology Data Exchange (ETDEWEB)

    Spouge, J.; Comer, P.

    1997-06-01

    A series of five studies have been carried out for the UK`s Environment Agency to assess the risks from the various aspects of the disposal routes for BSE (Bovine Spongiform Encephalopathy) infected cattle in England and Wales. These studies are entitled: an overview of the risks from BSE via environmental pathways; risks from burning rendered products from the over thirty month scheme in power stations; risks from disposing of BSE infected cattle in animal carcase incinerators; assessment of risk from BSE carcases in landfills; and Thruxted Mill rendering plant: risk assessment of waste water disposal options. The second study assessed the risks of injection for humans from all emissions and waste products from coal-fired power stations burning meat and bone meal (MBM) and tallow. The societal risks (total human ingestion of infectivity) and the individual risk (ingestion of infectivity by the most exposed person) by burning MBM was extremely small (2 x 10{sup -4} human 1D{sub 50} units and 3 x 10{sup -11} human 1D{sub 50} units respectively). The largest potential risk appears to be the ingestion of infectivity through drinking water abstracted from the ground.

  9. Conversion of the BASE prion strain into the BSE strain: the origin of BSE?

    Directory of Open Access Journals (Sweden)

    Raffaella Capobianco

    2007-03-01

    Full Text Available Atypical neuropathological and molecular phenotypes of bovine spongiform encephalopathy (BSE have recently been identified in different countries. One of these phenotypes, named bovine "amyloidotic" spongiform encephalopathy (BASE, differs from classical BSE for the occurrence of a distinct type of the disease-associated prion protein (PrP, termed PrP(Sc, and the presence of PrP amyloid plaques. Here, we show that the agents responsible for BSE and BASE possess different biological properties upon transmission to transgenic mice expressing bovine PrP and inbred lines of nontransgenic mice. Strikingly, serial passages of the BASE strain to nontransgenic mice induced a neuropathological and molecular disease phenotype indistinguishable from that of BSE-infected mice. The existence of more than one agent associated with prion disease in cattle and the ability of the BASE strain to convert into the BSE strain may have important implications with respect to the origin of BSE and spongiform encephalopathies in other species, including humans.

  10. Development of a risk assessment for BSE in the aquatic environment.

    Science.gov (United States)

    Gale, P; Young, C; Stanfield, G; Oakes, D

    1998-04-01

    Bovine spongiform encephalopathy (BSE) is believed to be transmitted by the ingestion of proteinaceous agents called prions which accumulate in the brain and spinal cord of infected bovines. Concern has been expressed about the risks of transmission of BSE to humans through BSE prions discharged to the aquatic environment from rendering plants, abattoirs and landfills. The disease-related form of the prion protein is relatively resistant to degradation, and infectivity decays rather slowly in the environment. Levels of disinfection used for drinking water treatment would have little effect. This paper presents the assumptions which were used to model the risks from a rendering plant disposing of cull cattle carcasses in the catchment of a chalk aquifer which is used for a drinking water abstraction. The risk assessment approach focused on identifying the hydrogeological and physical barriers which would contribute to preventing BSE infectivity gaining entry to the aquifer. These barriers included inactivation of BSE agent by the rendering process, removal from the effluent by treatment at the plant, filtration and adsorption in the clay and chalk, and dilution in the ground water. The importance in environmental risk assessment of the cow-to-man species barrier is considered. Two key conclusions about the environmental behaviour of the BSE agent are that prion proteins are 'sticky' and bind to particulates, and that the millions of BSE prion molecules comprising a human oral ID50 are subject to some degree of dispersion and hence dilution in the environment. Assuming the rendering plant processes 2000 cull cattle carcasses per week, the risks to drinking water consumers were estimated to be remote. Indeed, even using worst case assumptions an individual would have to consume 21 d-1 of tap water for 45 million years to have a 50% chance of infection through drinking water drawn from the aquifer.

  11. Isolation of prion with BSE properties from farmed goat.

    Science.gov (United States)

    Spiropoulos, John; Lockey, Richard; Sallis, Rosemary E; Terry, Linda A; Thorne, Leigh; Holder, Thomas M; Beck, Katy E; Simmons, Marion M

    2011-12-01

    Transmissible spongiform encephalopathies are fatal neurodegenerative diseases that include variant Creutzfeldt-Jakob disease in humans, scrapie in small ruminants, and bovine spongiform encephalopathy (BSE) in cattle. Scrapie is not considered a public health risk, but BSE has been linked to variant Creutzfeldt-Jakob disease. Small ruminants are susceptible to BSE, and in 2005 BSE was identified in a farmed goat in France. We confirm another BSE case in a goat in which scrapie was originally diagnosed and retrospectively identified as suspected BSE. The prion strain in this case was further characterized by mouse bioassay after extraction from formaldehyde-fixed brain tissue embedded in paraffin blocks. Our data show that BSE can infect small ruminants under natural conditions and could be misdiagnosed as scrapie. Surveillance should continue so that another outbreak of this zoonotic transmissible spongiform encephalopathy can be prevented and public health safeguarded.

  12. Spatial analysis of BSE cases in the Netherlands

    Directory of Open Access Journals (Sweden)

    Brus Dick J

    2008-06-01

    Full Text Available Abstract Background In many of the European countries affected by Bovine Spongiform Encephalopathy (BSE, case clustering patterns have been observed. Most of these patterns have been interpreted in terms of heterogeneities in exposure of cattle to the BSE agent. Here we investigate whether spatial clustering is present in the Dutch BSE case data. Results We have found three spatial case clusters in the Dutch BSE epidemic. The clusters are geographically distinct and each cluster appears in a different birth cohort. When testing all birth cohorts together, only one significant cluster was detected. The fact that we found stronger spatial clustering when using a cohort-based analysis, is consistent with the evidence that most BSE infections occur in animals less than 12 or 18 months old. Conclusion Significant spatial case clustering is present in the Dutch BSE epidemic. The spatial clusters of BSE cases are most likely due to time-dependent heterogeneities in exposure related to feed production.

  13. Sheep and Goat BSE Propagate More Efficiently than Cattle BSE in Human PrP Transgenic Mice

    OpenAIRE

    2011-01-01

    A new variant of Creutzfeldt Jacob Disease (vCJD) was identified in humans and linked to the consumption of Bovine Spongiform Encephalopathy (BSE)-infected meat products. Recycling of ruminant tissue in meat and bone meal (MBM) has been proposed as origin of the BSE epidemic. During this epidemic, sheep and goats have been exposed to BSE-contaminated MBM. It is well known that sheep can be experimentally infected with BSE and two field BSE-like cases have been reported in goats. In this work ...

  14. Consumption of bovine spongiform encephalopathy (BSE) contaminated beef and the risk of variant Creutzfeldt-Jakob disease.

    Science.gov (United States)

    Chen, Chu-Chih; Wang, Yin-Han; Wu, Kuen-Yuh

    2013-11-01

    To date, the variant Creutzfeldt-Jakob disease (vCJD) risk assessments that have been performed have primarily focused on predicting future vCJD cases in the United Kingdom, which underwent a bovine spongiform encephalopathy (BSE) epidemic between 1980 and 1996. Surveillance of potential BSE cases was also used to assess vCJD risk, especially in other BSE-prevalent EU countries. However, little is known about the vCJD risk for uninfected individuals who accidentally consume BSE-contaminated meat products in or imported from a country with prevalent BSE. In this article, taking into account the biological mechanism of abnormal prion PrP(res) aggregation in the brain, the probability of exposure, and the expected amount of ingested infectivity, we establish a stochastic mean exponential growth model of lifetime exposure through dietary intake. Given the findings that BSE agents behave similarly in humans and macaques, we obtained parameter estimates from experimental macaque data. We then estimated the accumulation of abnormal prions to assess lifetime risk of developing clinical signs of vCJD. Based on the observed number of vCJD cases and the estimated number of exposed individuals during the BSE epidemic period from 1980 to 1996 in the United Kingdom, an exposure threshold hypothesis is proposed. Given the age-specific risk of infection, the hypothesis explains the observations very well from an extreme-value distribution fitting of the estimated BSE infectivity exposure. The current BSE statistics in the United Kingdom are provided as an example.

  15. Sheep and goat BSE propagate more efficiently than cattle BSE in human PrP transgenic mice.

    Science.gov (United States)

    Padilla, Danielle; Béringue, Vincent; Espinosa, Juan Carlos; Andreoletti, Olivier; Jaumain, Emilie; Reine, Fabienne; Herzog, Laetitia; Gutierrez-Adan, Alfonso; Pintado, Belen; Laude, Hubert; Torres, Juan Maria

    2011-03-01

    A new variant of Creutzfeldt Jacob Disease (vCJD) was identified in humans and linked to the consumption of Bovine Spongiform Encephalopathy (BSE)-infected meat products. Recycling of ruminant tissue in meat and bone meal (MBM) has been proposed as origin of the BSE epidemic. During this epidemic, sheep and goats have been exposed to BSE-contaminated MBM. It is well known that sheep can be experimentally infected with BSE and two field BSE-like cases have been reported in goats. In this work we evaluated the human susceptibility to small ruminants-passaged BSE prions by inoculating two different transgenic mouse lines expressing the methionine (Met) allele of human PrP at codon 129 (tg650 and tg340) with several sheep and goat BSE isolates and compared their transmission characteristics with those of cattle BSE. While the molecular and neuropathological transmission features were undistinguishable and similar to those obtained after transmission of vCJD in both transgenic mouse lines, sheep and goat BSE isolates showed higher transmission efficiency on serial passaging compared to cattle BSE. We found that this higher transmission efficiency was strongly influenced by the ovine PrP sequence, rather than by other host species-specific factors. Although extrapolation of results from prion transmission studies by using transgenic mice has to be done very carefully, especially when human susceptibility to prions is analyzed, our results clearly indicate that Met129 homozygous individuals might be susceptible to a sheep or goat BSE agent at a higher degree than to cattle BSE, and that these agents might transmit with molecular and neuropathological properties indistinguishable from those of vCJD. Our results suggest that the possibility of a small ruminant BSE prion as vCJD causal agent could not be ruled out, and that the risk for humans of a potential goat and/or sheep BSE agent should not be underestimated.

  16. Sheep and goat BSE propagate more efficiently than cattle BSE in human PrP transgenic mice.

    Directory of Open Access Journals (Sweden)

    Danielle Padilla

    2011-03-01

    Full Text Available A new variant of Creutzfeldt Jacob Disease (vCJD was identified in humans and linked to the consumption of Bovine Spongiform Encephalopathy (BSE-infected meat products. Recycling of ruminant tissue in meat and bone meal (MBM has been proposed as origin of the BSE epidemic. During this epidemic, sheep and goats have been exposed to BSE-contaminated MBM. It is well known that sheep can be experimentally infected with BSE and two field BSE-like cases have been reported in goats. In this work we evaluated the human susceptibility to small ruminants-passaged BSE prions by inoculating two different transgenic mouse lines expressing the methionine (Met allele of human PrP at codon 129 (tg650 and tg340 with several sheep and goat BSE isolates and compared their transmission characteristics with those of cattle BSE. While the molecular and neuropathological transmission features were undistinguishable and similar to those obtained after transmission of vCJD in both transgenic mouse lines, sheep and goat BSE isolates showed higher transmission efficiency on serial passaging compared to cattle BSE. We found that this higher transmission efficiency was strongly influenced by the ovine PrP sequence, rather than by other host species-specific factors. Although extrapolation of results from prion transmission studies by using transgenic mice has to be done very carefully, especially when human susceptibility to prions is analyzed, our results clearly indicate that Met129 homozygous individuals might be susceptible to a sheep or goat BSE agent at a higher degree than to cattle BSE, and that these agents might transmit with molecular and neuropathological properties indistinguishable from those of vCJD. Our results suggest that the possibility of a small ruminant BSE prion as vCJD causal agent could not be ruled out, and that the risk for humans of a potential goat and/or sheep BSE agent should not be underestimated.

  17. Comparison of the historic recycling risk for BSE in three European countries by calculating the basic reproduction ratio R0.

    Science.gov (United States)

    Schwermer, Heinzpeter; de Koeijer, Aline; Brülisauer, Franz; Heim, Dagmar

    2007-10-01

    A deterministic model of BSE transmission is used to calculate the R(0) values for specific years of the BSE epidemics in the United Kingdom (UK), the Netherlands (NL), and Switzerland (CH). In all three countries, the R(0) values decreased below 1 after the introduction of a ban on feeding meat and bone meal (MBM) to ruminants around the 1990s. A variety of additional measures against BSE led to further decrease of R(0) to about 0.06 in the years around 1998. The calculated R(0) values were consistent with the observations made on the surveillance results for UK, but were partially conflicting with the surveillance results for NL and CH. There was evidence for a dependency of the BSE epidemic in NL and CH from an infection source not considered in the deterministic transmission model. Imports of MBM and feed components can be an explanation for this discrepancy, and the importance of imports for these observations is discussed.

  18. Factors that influence the age distribution of BSE cases: potentials for age targeting in surveillance

    NARCIS (Netherlands)

    Koeijer, de A.; Schreuder, B.; Bouma, A.

    2002-01-01

    Recently, due to consumers fears concerning BSE and vCJD, the need arose for methods to detect BSE, to estimate the present prevalence of BSE among cattle and to predict future BSE prevalence. As a part of that set of urgent questions, it has become important to indicate groups in which BSE risk is

  19. Bovine Spongiform Encephalopathy (BSE, Mad Cow Disease

    Directory of Open Access Journals (Sweden)

    G. K. Bruckner

    1997-07-01

    Full Text Available Mad Cow Disease or BSE (Bovine Spongiform Encephalopathy became a household name internationally and also in South Africa. International hysteria resulted following reports of a possible link between a disease diagnosed in cattle in Britain and a variant of the disease diagnosed in humans after the presumed ingestion or contact with meat from infected cattle. The European Union instituted a ban on the importation of beef from the United Kingdom during March 1996 that had a severe effect on the beef industry in the UK and also resulted in a world wide consumer resistance against beef consumption.

  20. Genotype-dependent molecular evolution of sheep bovine spongiform encephalopathy (BSE) prions in vitro affects their zoonotic potential.

    Science.gov (United States)

    Krejciova, Zuzana; Barria, Marcelo A; Jones, Michael; Ironside, James W; Jeffrey, Martin; González, Lorenzo; Head, Mark W

    2014-09-19

    Prion diseases are rare fatal neurological conditions of humans and animals, one of which (variant Creutzfeldt-Jakob disease) is known to be a zoonotic form of the cattle disease bovine spongiform encephalopathy (BSE). What makes one animal prion disease zoonotic and others not is poorly understood, but it appears to involve compatibility between the prion strain and the host prion protein sequence. Concerns have been raised that the United Kingdom sheep flock may have been exposed to BSE early in the cattle BSE epidemic and that serial BSE transmission in sheep might have resulted in adaptation of the agent, which may have come to phenotypically resemble scrapie while maintaining its pathogenicity for humans. We have modeled this scenario in vitro. Extrapolation from our results suggests that if BSE were to infect sheep in the field it may, with time and in some sheep genotypes, become scrapie-like at the molecular level. However, the results also suggest that if BSE in sheep were to come to resemble scrapie it would lose its ability to affect humans.

  1. Spatial analysis of BSE cases in the Netherlands

    NARCIS (Netherlands)

    Heres, L.; Brus, D.J.; Hagenaars, T.H.J.

    2008-01-01

    Background: In many of the European countries affected by Bovine Spongiform Encephalopathy (BSE), case clustering patterns have been observed. Most of these patterns have been interpreted in terms of heterogeneities in exposure of cattle to the BSE agent. Here we investigate whether spatial clusteri

  2. Trends in Substitution Models of Molecular Evolution

    Directory of Open Access Journals (Sweden)

    Miguel eArenas

    2015-10-01

    Full Text Available Substitution models of evolution describe the process of genetic variation through fixed mutations and constitute the basis of the evolutionary analysis at the molecular level. Almost forty years after the development of first substitution models, highly sophisticated and data-specific substitution models continue emerging with the aim of better mimicking real evolutionary processes. Here I describe current trends in substitution models of DNA, codon and amino acid sequence evolution, including advantages and pitfalls of the most popular models. The perspective concludes that despite the large number of currently available substitution models, further research is required for more realistic modeling, especially for DNA coding and amino acid data. Additionally, the development of more accurate complex models should be coupled with new implementations and improvements of methods and frameworks for substitution model selection and downstream evolutionary analysis.

  3. Molecular, biochemical and genetic characteristics of BSE in Canada.

    Science.gov (United States)

    Dudas, Sandor; Yang, Jianmin; Graham, Catherine; Czub, Markus; McAllister, Tim A; Coulthart, Michael B; Czub, Stefanie

    2010-05-14

    The epidemiology and possibly the etiology of bovine spongiform encephalopathy (BSE) have recently been recognized to be heterogeneous. In particular, three types [classical (C) and two atypical (H, L)] have been identified, largely on the basis of characteristics of the proteinase K (PK)-resistant core of the misfolded prion protein associated with the disease (PrP(res)). The present study was conducted to characterize the 17 Canadian BSE cases which occurred prior to November 2009 based on the molecular and biochemical properties of their PrP(res), including immunoreactivity, molecular weight, glycoform profile and relative PK sensitivity. Two cases exhibited molecular weight and glycoform profiles similar to those of previously reported atypical cases, one corresponding to H-type BSE (case 6) and the other to L-type BSE (case 11). All other cases were classified as C-type. PK digestion under mild and stringent conditions revealed a reduced protease resistance in both of these cases compared to the C-type cases. With Western immunoblotting, N-terminal-specific antibodies bound to PrP(res) from case 6 but not to that from case 11 or C-type cases. C-terminal-specific antibodies revealed a shift in the glycoform profile and detected a fourth protein fragment in case 6, indicative of two PrP(res) subpopulations in H-type BSE. No mutations suggesting a genetic etiology were found in any of the 17 animals by sequencing the full PrP-coding sequence in exon 3 of the PRNP gene. Thus, each of the three known BSE types have been confirmed in Canadian cattle and show molecular characteristics highly similar to those of classical and atypical BSE cases described from Europe, Japan and the USA. The occurrence of atypical cases of BSE in countries such as Canada with low BSE prevalence and transmission risk argues for the occurrence of sporadic forms of BSE worldwide.

  4. Molecular, biochemical and genetic characteristics of BSE in Canada.

    Directory of Open Access Journals (Sweden)

    Sandor Dudas

    Full Text Available The epidemiology and possibly the etiology of bovine spongiform encephalopathy (BSE have recently been recognized to be heterogeneous. In particular, three types [classical (C and two atypical (H, L] have been identified, largely on the basis of characteristics of the proteinase K (PK-resistant core of the misfolded prion protein associated with the disease (PrP(res. The present study was conducted to characterize the 17 Canadian BSE cases which occurred prior to November 2009 based on the molecular and biochemical properties of their PrP(res, including immunoreactivity, molecular weight, glycoform profile and relative PK sensitivity. Two cases exhibited molecular weight and glycoform profiles similar to those of previously reported atypical cases, one corresponding to H-type BSE (case 6 and the other to L-type BSE (case 11. All other cases were classified as C-type. PK digestion under mild and stringent conditions revealed a reduced protease resistance in both of these cases compared to the C-type cases. With Western immunoblotting, N-terminal-specific antibodies bound to PrP(res from case 6 but not to that from case 11 or C-type cases. C-terminal-specific antibodies revealed a shift in the glycoform profile and detected a fourth protein fragment in case 6, indicative of two PrP(res subpopulations in H-type BSE. No mutations suggesting a genetic etiology were found in any of the 17 animals by sequencing the full PrP-coding sequence in exon 3 of the PRNP gene. Thus, each of the three known BSE types have been confirmed in Canadian cattle and show molecular characteristics highly similar to those of classical and atypical BSE cases described from Europe, Japan and the USA. The occurrence of atypical cases of BSE in countries such as Canada with low BSE prevalence and transmission risk argues for the occurrence of sporadic forms of BSE worldwide.

  5. Toy models for macroevolutionary patterns and trends.

    Science.gov (United States)

    Alicea, Bradly; Gordon, Richard

    2014-09-01

    Many models have been used to simplify and operationalize the subtle but complex mechanisms of biological evolution. Toy models are gross simplifications that nevertheless attempt to retain major essential features of evolution, bridging the gap between empirical reality and formal theoretical understanding. In this paper, we examine thirteen models which describe evolution that also qualify as such toy models, including the tree of life, branching processes, adaptive ratchets, fitness landscapes, and the role of nonlinear avalanches in evolutionary dynamics. Such toy models are intended to capture features such as evolutionary trends, coupled evolutionary dynamics of phenotype and genotype, adaptive change, branching, and evolutionary transience. The models discussed herein are applied to specific evolutionary contexts in various ways that simplify the complexity inherent in evolving populations. While toy models are overly simplistic, they also provide sufficient dynamics for capturing the fundamental mechanism(s) of evolution. Toy models might also be used to aid in high-throughput data analysis and the understanding of cultural evolutionary trends. This paper should serve as an introductory guide to the toy modeling of evolutionary complexity.

  6. Exploring the risks of a putative transmission of BSE to new species.

    Science.gov (United States)

    Vidal, Enric; Fernández-Borges, Natalia; Pintado, Belén; Ordóñez, Montserrat; Márquez, Mercedes; Fondevila, Dolors; Eraña, Hasier; Torres, Juan María; Pumarola, Martí; Castilla, Joaquín

    2013-01-01

    The prion responsible for the Bovine Spongiform Encephalopathy (BSE) shows unique features when compared with other prions. One of these features is its ability to infect almost all experimentally tested animal models. In the paper published in The Journal of Neuroscience (1) we describe a series of experiments directed toward elucidating which would be the in vivo behavior of BSE if it would infect dogs and rabbits, two alleged prion resistant species. Protein misfolding cyclic amplification (PMCA) was used to generate canidae and leporidae in vitro adapted BSE prions. A characterization of their in vivo pathobiological properties showed that BSE prions were capable not only of adapting to new species but they maintained, in the case of rabbits, their ability to infect transgenic mice expressing human PrP. The remarkable adaptation ability of certain prions implies that any new host species could lead to the emergence of new infectious agents with unpredictable transmission potential. Our results suggest that caution must be taken when considering the use of any mammal derived protein in feedstuffs.

  7. Television signal transmission characteristics via BSE

    Science.gov (United States)

    Kozu, T.; Yamamoto, M.; Ohuchi, C.; Sugimoto, Y.; Fukuchi, H.

    1986-01-01

    The FM-TV signal transmission characteristics via BSE measured at the Main Transit and Receiving Station are described. Measurements are reported using 'standard parameters' which were carried out every half year from 1978 to 1980, measuring the video signal to noise ratio, waveform distortion, DG-DP, amplitude-frequency characteristics of video and audio signal, and the subjective assessment of video signal quality. These characteristics were good enough to broadcast a high-quality TV signal, and no degradation was observed for two years. Measurements using 'nonstandard parameters' were performed in order to study transmission parameters suitable for satellite broadcasting. Results are reported for one sound channel transmission using one FM subcarrier and for two sound channel transmission using two FM subcarriers.

  8. In-orbit performance of BSE transponders

    Science.gov (United States)

    Fukuchi, H.; Yamamoto, M.; Yazawa, N.; Morishita, Y.

    The Japanese Medium Scale Broadcasting Satellite for Experimental Purposes (BSE) was successfully positioned in a geostationary orbit on April 26, 1978. Various kinds of transmission characteristics were periodically measured every half year including frequency characteristics, and input-output characteristics of each electronics unit which made up a high power, 100 W, transponder. No remarkable degradation of their characteristics was observed for about two years, and the characteristics of the in-orbit satellite transponders almost coincided with the designed values or the values measured prior to the launching. FM television signal (FM-TV) transmission characteristics were also measured periodically. From these measurements it was found that the qualities of the television picture and sound were not reduced to any extent by the high power transponders.

  9. The BSE risk of processing meat and bone meal in nonruminant feed: a quantitative assessment for the Netherlands.

    Science.gov (United States)

    de Vos, Clazien J; Heres, Lourens

    2009-04-01

    The total ban on use of meat and bone meal (MBM) in livestock feed has been very successful in reducing bovine spongiform encephalopathy (BSE) spread, but also implies a waste of high-quality proteins resulting in economic and ecological loss. Now that the BSE epidemic is fading out, a partial lifting of the MBM ban might be considered. The objective of this study was to assess the BSE risk for the Netherlands if MBM derived from animals fit for human consumption, i.e., category 3 MBM, would be used in nonruminant feed. A stochastic simulation model was constructed that calculates (1) the probability that infectivity of undetected BSE-infected cows ends up with calves and (2) the quantity of infectivity (Q(inf)) consumed by calves in case of such an incident. Three pathways were considered via which infectivity can reach cattle: (1) cross-contamination in the feed mill, (2) cross-contamination on the primary farm, and (3) pasture contamination. Model calculations indicate that the overall probability that infectivity ends up with calves is 3.2%. In most such incidents the Q(inf) is extremely small (median = 6.5 x 10(-12) ID(50); mean = 1.8 x 10(-4) ID(50)), corresponding to an average probability of 1.3 x 10(-4) that an incident results in >or=1 new BSE infections. Cross-contamination in the feed mill is the most risky pathway. Combining model results with Dutch BSE prevalence estimates for the coming years, it can be concluded that the BSE risk of using category 3 MBM derived from Dutch cattle in nonruminant feed is very low.

  10. Identification of a heritable polymorphism in bovine PRNP associated with genetic transmissible spongiform encephalopathy: evidence of heritable BSE

    Science.gov (United States)

    Bovine spongiform encephalopathy (BSE) is a transmissible spongiform encephalopathy (TSE) of cattle. Classical BSE is associated with ingestion of BSE-contaminated feedstuffs. H- and L-type BSE, collectively known as atypical BSE, differ from classical BSE by displaying a different disease phenoty...

  11. Identification of a heritable polymorphism in the bovine prion gene associated with genetic transmissible spongiform encephalopathy: evidence of heritable BSE

    Science.gov (United States)

    Background: Bovine spongiform encephalopathy (BSE) is a transmissible spongiform encephalopathy (TSE) of cattle. Classical BSE is associated with ingestion of BSE-contaminated feedstuffs. H- and L-type BSE, collectively known as atypical BSE, differ from classical BSE by displaying a different di...

  12. New Trends in European Companies’ Business Models

    Directory of Open Access Journals (Sweden)

    Georgeta ILIE

    2014-01-01

    Full Text Available Companies constantly reconsider and reconfigure their business models in order to create value and generate growth. They also reassess the price-performance correlation and new levels of capital efficiency. The new business models are frequently needed to provide goods at affordable prices through the adaptation of packaging strategies, pricing strategies, the product itself, and by helping to sustain financially the demand. In the context of current financial and economic difficulties, it reveals the inclusive business models that provide goods and services to poor people and also create employment. The paper tries to emphasize ways in which business models are evolving, and how to determine the right model for companies. In the same time, it also seeks to highlight trends in the development of new business models in the European countries which creates basic economic activities, giving people facing social and economic problems access to products and services that meet their needs.

  13. Identification of H-type BSE in Portugal.

    Science.gov (United States)

    Orge, Leonor; Machado, Carla Guedes; Ramalho, Luísa; Carvalho, Renata; Silva, João; Almeida, Paula; Tavares, Paula; Ochoa, Cristina; Lima, Carla; Pinto, Maria J Marques; Simas, J Pedro

    2015-01-01

    During the bovine spongiform encephalopathy (BSE) epidemic, Portugal was the third most affected country. As a result of a successful national eradication plan, the number of BSE affected animals has been progressively declining in Portugal with no cases identified in 2013. However, within the scope of this active surveillance scheme, we have identified the first H-type BSE case born after the introduction of the reinforced ban in fallen stock. Here, we report the phenotypic features of this case and the analysis of the protein coding sequence of prnp as well as the prnp promoter and intron 1 insertion-deletions.

  14. Trends in modeling of porous media combustion

    Energy Technology Data Exchange (ETDEWEB)

    Mujeebu, M. Abdul; Abdullah, M. Zulkifly [Porous Media Combustion Laboratory, School of Mechanical Engineering, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Penang (Malaysia); Mohamad, A.A. [College of Engineering, Alfaisal University, Riyadh 11533, P.O. Box 50927 (Saudi Arabia); Bakar, M.Z. Abu [School of Chemical Engineering, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Penang (Malaysia)

    2010-12-15

    Porous media combustion (PMC) has interesting advantages compared with free flame combustion due to higher burning rates, increased power dynamic range, extension of the lean flammability limits, and low emissions of pollutants. Extensive experimental and numerical works were carried out and are still underway, to explore the feasibility of this interesting technology for practical applications. For this purpose, numerical modeling plays a crucial role in the design and development of promising PMC systems. This article provides an exhaustive review of the fundamental aspects and emerging trends in numerical modeling of gas combustion in porous media. The modeling works published to date are reviewed, classified according to their objectives and presented with general conclusions. Numerical modeling of liquid fuel combustion in porous media is excluded. (author)

  15. Consequences of BSE disease outbreaks in the Canadian beef industry

    Directory of Open Access Journals (Sweden)

    L. Čechura

    2011-03-01

    Full Text Available This study examines farm to wholesale prices spreads to measure the impact of the BSE disease outbreak on the Canadian beef industry. The study uses structure break tests developed by Gregory and Hansen (1996 and Hansen (1992 examine possible breaks within co integrating relationships. The study finds evidence that the industry began realignment as a result of the UK BSE disease outbreak, and the Canadian BSE disease outbreak was simply the largest realignment of the process beginning with the UK disease outbreak. However, the only statistically significant break was the BSE disease outbreak itself in May 2003. Stability was not restored until the border was reopened in 2005. Specific results indicated that the processing sector exploited the border closure in May 2003 to enhance its market power and that the system returned to a competitive one after the border re-opened in July 2005.

  16. Understanding the pattern of the BSE Sensex

    Science.gov (United States)

    Mukherjee, I.; Chatterjee, Soumya; Giri, A.; Barat, P.

    2017-09-01

    An attempt is made to understand the pattern of behaviour of the BSE Sensex by analysing the tick-by-tick Sensex data for the years 2006 to 2012 on yearly as well as cumulative basis using Principal Component Analysis (PCA) and its nonlinear variant Kernel Principal Component Analysis (KPCA). The latter technique ensures that the nonlinear character of the interactions present in the system gets captured in the analysis. The analysis is carried out by constructing vector spaces of varying dimensions. The size of the data set ranges from a minimum of 360,000 for one year to a maximum of 2,520,000 for seven years. In all cases the prices appear to be highly correlated and restricted to a very low dimensional subspace of the original vector space. An external perturbation is added to the system in the form of noise. It is observed that while standard PCA is unable to distinguish the behaviour of the noise-mixed data from that of the original, KPCA clearly identifies the effect of the noise. The exercise is extended in case of daily data of other stock markets and similar results are obtained.

  17. Ante mortem identification of BSE from serum using infrared spectroscopy

    Science.gov (United States)

    Schmitt, Jürgen; Lasch, Peter; Beekes, Michael; Udelhoven, Thomas; Eiden, Michael; Fabian, Heinz; Petrich, Wolfgang H.; Naumann, Dieter

    2004-07-01

    In our former studies a diagnostic approach for the detection of transmissible spongiform encephalopaties (TSE) based on FT-IR spectroscopy in combination with artificial neural networks was described, based on a controlled animal study with terminally ill Syrian hamsters and control animals. As a consequence of the bovine spongiform encephalopathy (BSE) crisis in Europe, the development of a disgnostic ante mortem test for cattle has become a matter of great scientific importance and public interest. Since 1986 more than 180,000 clinical cases of BSE have been observed in the UK alone. Most of these cases were confirmed by post mortem examination of brain tissue. However, BSE-related risk assessment and risk-management would greatly benefit from ante mortem testing on living animals. For example, a serum-based test could allow for screening of the cattle population, thus, even a BSE eradication program would be conceivable. Here we report on a novel method for ante mortem BSE testing, which combines infrared spectroscopy of serum samples with multivariate pattern recognition analysis. A classification algorithm was trained using infrared spectra of sera from more than 800 animals from a field study (including BSE positive, healthy controls and animals suffering from viral or bacterial infections). In two validation studies sensitivities of 85% and 87% and specificities of 84% and 91% were achieved, respectively. The combination of classification algorithms increased sensitivity and specificity to 96% and 92%, respectively.

  18. Modeling Alaska boreal forests with a controlled trend surface approach

    Science.gov (United States)

    Mo Zhou; Jingjing Liang

    2012-01-01

    An approach of Controlled Trend Surface was proposed to simultaneously take into consideration large-scale spatial trends and nonspatial effects. A geospatial model of the Alaska boreal forest was developed from 446 permanent sample plots, which addressed large-scale spatial trends in recruitment, diameter growth, and mortality. The model was tested on two sets of...

  19. Trends in development of innovative business models

    Directory of Open Access Journals (Sweden)

    Krstić Milan

    2016-01-01

    Full Text Available The companies doing business in global markets are now compelled to do it in conditions of permanent and turbulent changes. In order to succeed within that kind of environment in the long run, they are to innovate and to continuously strengthen their own innovative strength. Consideration of gaining its own innovative strength becomes top agenda issue of strategic companies. To that purpose, this paper presents the shortened results of a desktop theoretical research that has been undertaken to improve the innovative power of companies. The survey and subsequent analysis identified relevant innovative business models (IBM of companies, some of which briefly presented (CANVAS, SHARE, and WOIS BLUE OCEAN Strategy, which now form the current IBM trend.

  20. [Effects of BSE on consumer attitudes and behavior].

    Science.gov (United States)

    von Alvenisleben, R

    2002-08-01

    The extremely high media emphasis of the BSE issue during the period December 2000 to February 2001 has caused considerable short term public concern. A significant amount of this concern was due to an intensive communication of pictures. Pictures are "fast shots into the brain" (Kroeber-Riel). Pictured stimuli run under the cognitive control of the recipients effecting the consumer below the threshold of consciousness. However, the issue has fallen into oblivion very soon. In summer 2001 the public concern was not higher than before the BSE crisis. The perception of product quality regained a "normal level". The public concern has caused a considerable decline of the demand for beef and an increase of demand for substitutes and organic meat. When the media emphasis of the BSE issue diminished, the beef demand recovered but did not reach the pre-crisis level again. However, the BSE crisis has intensified animal welfare concerns, polarized public opinion about food and agriculture and had big effects in the political sphere. Furthermore, the BSE crisis has led to additional--politically supported--activities of the organic food suppliers causing a further growth of this market segment.

  1. BSE case associated with prion protein gene mutation.

    Directory of Open Access Journals (Sweden)

    Jürgen A Richt

    Full Text Available Bovine spongiform encephalopathy (BSE is a transmissible spongiform encephalopathy (TSE of cattle and was first detected in 1986 in the United Kingdom. It is the most likely cause of variant Creutzfeldt-Jakob disease (CJD in humans. The origin of BSE remains an enigma. Here we report an H-type BSE case associated with the novel mutation E211K within the prion protein gene (Prnp. Sequence analysis revealed that the animal with H-type BSE was heterozygous at Prnp nucleotides 631 through 633. An identical pathogenic mutation at the homologous codon position (E200K in the human Prnp has been described as the most common cause of genetic CJD. This finding represents the first report of a confirmed case of BSE with a potential pathogenic mutation within the bovine Prnp gene. A recent epidemiological study revealed that the K211 allele was not detected in 6062 cattle from commercial beef processing plants and 42 cattle breeds, indicating an extremely low prevalence of the E211K variant (less than 1 in 2000 in cattle.

  2. Histopathological studies of "CH1641-like" scrapie sources versus classical scrapie and BSE transmitted to ovine transgenic mice (TgOvPrP4.

    Directory of Open Access Journals (Sweden)

    Anna Bencsik

    Full Text Available The possibility of the agent causing bovine spongiform encephalopathy (BSE infecting small ruminants is of serious concern for human health. Among scrapie cases, the CH1641 source in particular appears to have certain biochemical properties similar to the BSE strain. In France, several natural scrapie cases were identified as "CH1641-like" natural scrapie isolates in sheep and goats. The Tg(OvPrP4 mouse line expressing the ovine prion protein is a sensitive model for studying and identifying strains of agents responsible for scrapie and BSE. This model is also very useful when studying specific scrapie source CH1641, known to be not transmissible to wild-type mice despite the similarity of some of its biochemical properties to those of the BSE strain. As it is important to be able to fully distinguish CH1641 from BSE, we herein report the histopathological data from CH1641 scrapie transmission experiments compared to specific cases of "CH1641-like" natural scrapie isolates in sheep, murine scrapie strains and BSE. In addition to the conventional vacuolar lesion profile approach and PrP(d brain mappings, an innovative differential PET-blot analysis was introduced to classify the different strains of agent and revealed the first direct concordance between ways of grouping strains on the basis of PrP(d biochemical characteristics.

  3. Histopathological studies of "CH1641-like" scrapie sources versus classical scrapie and BSE transmitted to ovine transgenic mice (TgOvPrP4).

    Science.gov (United States)

    Bencsik, Anna; Baron, Thierry

    2011-01-01

    The possibility of the agent causing bovine spongiform encephalopathy (BSE) infecting small ruminants is of serious concern for human health. Among scrapie cases, the CH1641 source in particular appears to have certain biochemical properties similar to the BSE strain. In France, several natural scrapie cases were identified as "CH1641-like" natural scrapie isolates in sheep and goats. The Tg(OvPrP4) mouse line expressing the ovine prion protein is a sensitive model for studying and identifying strains of agents responsible for scrapie and BSE. This model is also very useful when studying specific scrapie source CH1641, known to be not transmissible to wild-type mice despite the similarity of some of its biochemical properties to those of the BSE strain. As it is important to be able to fully distinguish CH1641 from BSE, we herein report the histopathological data from CH1641 scrapie transmission experiments compared to specific cases of "CH1641-like" natural scrapie isolates in sheep, murine scrapie strains and BSE. In addition to the conventional vacuolar lesion profile approach and PrP(d) brain mappings, an innovative differential PET-blot analysis was introduced to classify the different strains of agent and revealed the first direct concordance between ways of grouping strains on the basis of PrP(d) biochemical characteristics.

  4. Time trends in exposure of cattle to bovine spongiform encephalopathy and cohort effect in France and Italy: value of the classical Age-Period-Cohort approach

    Directory of Open Access Journals (Sweden)

    Ru Giuseppe

    2009-09-01

    Full Text Available Abstract Background The Age-Period-Cohort (APC analysis is routinely used for time trend analysis of cancer incidence or mortality rates, but in veterinary epidemiology, there are still only a few examples of this application. APC models were recently used to model the French epidemic assuming that the time trend for BSE was mainly due to a cohort effect in relation to the control measures that may have modified the BSE exposure of cohorts over time. We used a categorical APC analysis which did not require any functional form for the effect of the variables, and examined second differences to estimate the variation of the BSE trend. We also reanalysed the French epidemic and performed a simultaneous analysis of Italian data using more appropriate birth cohort categories for comparison. Results We used data from the exhaustive surveillance carried out in France and Italy between 2001 and 2007, and comparatively described the trend of the epidemic in both countries. At the end, the shape and irregularities of the trends were discussed in light of the main control measures adopted to control the disease. In Italy a decrease in the epidemic became apparent from 1996, following the application of rendering standards for the processing of specific risk material (SRM. For the French epidemic, the pattern of second differences in the birth cohorts confirmed the beginning of the decrease from 1995, just after the implementation of the meat and bone meal (MBM ban for all ruminants (1994. Conclusion The APC analysis proved to be highly suitable for the study of the trend in BSE epidemics and was helpful in understanding the effects of management and control of the disease. Additionally, such an approach may help in the implementation of changes in BSE regulations.

  5. Characterizing economic trends by Bayesian stochastic model specification search

    DEFF Research Database (Denmark)

    Grassi, Stefano; Proietti, Tommaso

    We extend a recently proposed Bayesian model selection technique, known as stochastic model specification search, for characterising the nature of the trend in macroeconomic time series. In particular, we focus on autoregressive models with possibly time-varying intercept and slope and decide...... on whether their parameters are fixed or evolutive. Stochastic model specification is carried out to discriminate two alternative hypotheses concerning the generation of trends: the trend-stationary hypothesis, on the one hand, for which the trend is a deterministic function of time and the short run......, estimated by a suitable Gibbs sampling scheme, provides useful insight on quasi-integrated nature of the specifications selected....

  6. [Risk assessment for importing bovine spongiform encephalopathy (BSE)].

    Science.gov (United States)

    Hörnlimann, B; Guidon, D; Griot, C

    1994-07-01

    Since the occurrence of bovine spongiform encephalopathy (BSE) in Switzerland in 1990, extensive epidemiological investigations and risk factor analyses were carried out. In this study, statistical data on meat and bone meal traded from 1985 to 1989 were analysed addressing the following questions: i) what amount of meat and bone meal was exported from Great Britain (GB) and where to and ii) what amount of meat and bone meal was imported into Switzerland and where from? The findings led to the hypothesis that imported material potentially infected with scrapie-like agents was the cause for BSE in Switzerland.

  7. Trend time-series modeling and forecasting with neural networks.

    Science.gov (United States)

    Qi, Min; Zhang, G Peter

    2008-05-01

    Despite its great importance, there has been no general consensus on how to model the trends in time-series data. Compared to traditional approaches, neural networks (NNs) have shown some promise in time-series forecasting. This paper investigates how to best model trend time series using NNs. Four different strategies (raw data, raw data with time index, detrending, and differencing) are used to model various trend patterns (linear, nonlinear, deterministic, stochastic, and breaking trend). We find that with NNs differencing often gives meritorious results regardless of the underlying data generating processes (DGPs). This finding is also confirmed by the real gross national product (GNP) series.

  8. [Comments on present-day spread and epidemiology of BSE and prion diseases].

    Science.gov (United States)

    Bodemer, W; Kaup, F-J

    2004-02-01

    Prion diseases of animals and man are neurological diseases with amyloidal deposition of the respective proteins. As to prion disease, the cellular prion protein is in its abnormal isoform(s) an essential component of prion protein aggregates found in affected tissue. In contrast to all neurodegenerative diseases like Morbus Alzheimer or Huntington's disease, prion diseases are transmissible. Therefore, prion diseases were designated Transmissible Spongiform Encephalopathies (TSE). The diseases have been well known for decades. Scrapie was first described around 1750, a BSE case was reported in the 1850-ties most likely a misdiagnosis, and in 1920/1930 the human Creutzfeldt-Jakob disease (CJD) had been described. Transmission of CJD i. e. Kuru had been suspected in the early 1950 s and was erroneously classified as slow virus disease. The CJD transmission posed a problem to humans when transplants from CJD cases were used for treatment. Fortunately, these iatrogenic transmissions remained limited. But with the advent of BSE and appearance of variant CJD cases in the UK and some places in Europe scientists suspected that transmission from cattle to man could have happened. From animal models we know of successful transmission via several routes. Species barriers do not completely prevent transmission. Rather, transmission barriers might exist controlling individual susceptibility against prions. Modes of transmission, susceptibility to transmission, identification of receptor molecules as well as molecular mechanisms of the transmission process are being investigated with great intensity. Current knowledge leads us to assume that inapparent stages of prion infection wrongly suggest a (non-existent) species barrier. This inapparent infection precedes overt disease, and, hence, most research focuses on the development of highly sensitive assay systems for detection of minute amounts of pathological prion protein in suspected cases. Inapparence also should warn us to

  9. Sheep prions with molecular properties intermediate between classical scrapie, BSE and CH1641-scrapie

    NARCIS (Netherlands)

    Langeveld, J.P.M.; Jacobs, J.G.; Erkens, J.H.F.; Baron, T.; Andreoletti, O.; Yokoyama, T.; Keulen, van L.J.M.; Zijderveld, van F.G.; Davidse, A.; Hope, J.; Tang, Y.; Bossers, A.

    2014-01-01

    Efforts to differentiate bovine spongiform encephalopathy (BSE) from scrapie in prion infected sheep have resulted
    in effective methods to decide about the absence of BSE. In rare instances uncertainties remain due to assumptions
    that BSE, classical scrapie and CH1641–a rare scrapie variant–

  10. Modelled long term trends of surface ozone over South Africa

    CSIR Research Space (South Africa)

    Naidoo, M

    2011-10-01

    Full Text Available timescale seeks to provide a spatially comprehensive view of trends while also creating a baseline for comparisons with future projections of air quality through the forcing of air quality models with modelled predicted long term meteorology. Previous...

  11. When do we need a trend model in kriging

    Energy Technology Data Exchange (ETDEWEB)

    Journel, A.G.; Rossi, M.E. (Stanford Univ., CA (USA))

    1989-10-01

    Under usual estimation practice with local search windows for data and for interpolation situations, universal kriging and ordinary kriging yield the same estimates, using a data set with apparent trend, for both the unknown attribute and its trend component. Modeling the trend matters only in extrapolation situations. Because conditions of the case study presented arise most frequently in practice, the simpler ordinary kriging is the preferred option.

  12. A spatio-temporal analysis of BSE cases born before and after the reinforced feed ban in France.

    Science.gov (United States)

    Ducrot, Christian; Abrial, David; Calavas, Didier; Carpenter, Tim

    2005-01-01

    A spatio-temporal analysis was carried out to see how the risk distribution of bovine spongiform encephalopathy (BSE) in France changed depending on the period of birth. The data concerned the 539 BSE cases born in France after the ban (BAB) of meat and bone meal (MBM) in 1990 and detected between July 1, 2001 and December 31, 2003, when the surveillance of BSE was comprehensive. Seventy-two of these cases were born after the reinforced (second) ban (BASB) in 1996, which involved the removal of BSE-risk materials and cadavers from the processing of MBM. The Ederer-Myers-Mantel (EMM) time and space cluster test was applied, after classifying the cases by trimester and region of birth, BAB or BASB status, and dairy or beef status. Then disease mapping was performed for four successive birth periods, three for the BAB cases (January 1991 through June 1994, July 1994 through June 1995, July 1995 through June 1996), and one for the BASB (July 1996 through October 1998). It was elaborated with the Bayesian graphical modelling methods and based on a Poisson distribution with spatial smoothing. The parameters were estimated by a Markov Chain Monte Carlo (MCMC) simulation method. The main finding was that the areas with the highest risk of BSE changed largely from one birth period to another; from the west, it reached the east of France for birth cohort 1994-1995 and the southwest for birth cohort 1995-1996. The EMM test identified a peak risk in this region both for dairy and beef cattle in the fall 1995. The spatial distribution of the risk for the BASB cases matched the spatial pattern of risk for the preceding BAB birth cohort quite well; this was in favour of a common origin of the infection of the BAB and BASB cases, despite the complementary control measures.

  13. Area-level risks for BSE in British cattle before and after the July 1988 meat and bone meal feed ban.

    Science.gov (United States)

    Stevenson, M A; Morris, R S; Lawson, A B; Wilesmith, J W; Ryan, J B M; Jackson, R

    2005-06-10

    In this paper we investigate area-level risk factors for BSE for the cattle population present in Great Britain between 1986 and 1997. By dividing this population into two birth cohorts, those born before the July 1988 ban on feeding ruminant-derived meat and bone meal to ruminants and those born after, second-order regional influences are distinguished from the strong first-order south-to-north gradient of area-level BSE risk using Bayesian hierarchical models that account for structured (spatially correlated) and unstructured heterogeneity in the data. For both cohorts area-level risk of BSE was increased by a more southerly location and greater numbers of dairy cattle, relative to non-dairy cattle. For the cohort of cattle born after the July 1988 ban on feeding ruminant-derived meat and bone meal area-level BSE risk was additionally associated with greater numbers of pigs, relative to cattle. These findings support the role of low level cross-contamination of cattle feed by pig feed as an influence on BSE incidence risk as the epidemic evolved. Prior to the 1988 meat and bone meal ban unexplained BSE risk was relatively uniformly distributed across the country whereas after the ban there were spatially aggregated areas of unexplained risk in the northern and eastern regions of England suggesting that local influences allowed BSE control measures to be less-successfully applied in these areas, compared with the rest of the country. We conclude that spatially localised influences were operating in divergent ways during the two phases of the epidemic.

  14. Trends

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Shanghai Mode Lingerie continually strives to underline its status as a veritable reference on the fashion scene: an opportunity to explore trends, interpret key directions and gain an in-depth overview of lines to follow.

  15. SDG and qualitative trend based model multiple scale validation

    Science.gov (United States)

    Gao, Dong; Xu, Xin; Yin, Jianjin; Zhang, Hongyu; Zhang, Beike

    2017-09-01

    Verification, Validation and Accreditation (VV&A) is key technology of simulation and modelling. For the traditional model validation methods, the completeness is weak; it is carried out in one scale; it depends on human experience. The SDG (Signed Directed Graph) and qualitative trend based multiple scale validation is proposed. First the SDG model is built and qualitative trends are added to the model. And then complete testing scenarios are produced by positive inference. The multiple scale validation is carried out by comparing the testing scenarios with outputs of simulation model in different scales. Finally, the effectiveness is proved by carrying out validation for a reactor model.

  16. Altitude dependence of atmospheric temperature trends: Climate models versus observation

    CERN Document Server

    Douglass, D H; Singer, F

    2004-01-01

    As a consequence of greenhouse forcing, all state of the art general circulation models predict a positive temperature trend that is greater for the troposphere than the surface. This predicted positive trend increases in value with altitude until it reaches a maximum ratio with respect to the surface of as much as 1.5 to 2.0 at about 200 to 400 hPa. However, the temperature trends from several independent observational data sets show decreasing as well as mostly negative values. This disparity indicates that the three models examined here fail to account for the effects of greenhouse forcings.

  17. A C-terminal protease-resistant prion fragment distinguishes ovine "CH1641-like" scrapie from bovine classical and L-Type BSE in ovine transgenic mice.

    Directory of Open Access Journals (Sweden)

    Thierry Baron

    Full Text Available The protease-resistant prion protein (PrP(res of a few natural scrapie isolates identified in sheep, reminiscent of the experimental isolate CH1641 derived from a British natural scrapie case, showed partial molecular similarities to ovine bovine spongiform encephalopathy (BSE. Recent discovery of an atypical form of BSE in cattle, L-type BSE or BASE, suggests that also this form of BSE might have been transmitted to sheep. We studied by Western blot the molecular features of PrP(res in four "CH1641-like" natural scrapie isolates after transmission in an ovine transgenic model (TgOvPrP4, to see if "CH1641-like" isolates might be linked to L-type BSE. We found less diglycosylated PrP(res than in classical BSE, but similar glycoform proportions and apparent molecular masses of the usual PrP(res form (PrP(res #1 to L-type BSE. However, the "CH1641-like" isolates differed from both L-type and classical BSE by an abundant, C-terminally cleaved PrP(res product (PrP(res #2 specifically recognised by a C-terminal antibody (SAF84. Differential immunoprecipitation of PrP(res #1 and PrP(res #2 resulted in enrichment in PrP(res #2, and demonstrated the presence of mono- and diglycosylated PrP(res products. PrP(res #2 could not be obtained from several experimental scrapie sources (SSBP1, 79A, Chandler, C506M3 in TgOvPrP4 mice, but was identified in the 87V scrapie strain and, in lower and variable proportions, in 5 of 5 natural scrapie isolates with different molecular features to CH1641. PrP(res #2 identification provides an additional method for the molecular discrimination of prion strains, and demonstrates differences between "CH1641-like" ovine scrapie and bovine L-type BSE transmitted in an ovine transgenic mouse model.

  18. A C-terminal protease-resistant prion fragment distinguishes ovine "CH1641-like" scrapie from bovine classical and L-Type BSE in ovine transgenic mice.

    Science.gov (United States)

    Baron, Thierry; Bencsik, Anna; Vulin, Johann; Biacabe, Anne-Gaëlle; Morignat, Eric; Verchere, Jérémy; Betemps, Dominique

    2008-08-29

    The protease-resistant prion protein (PrP(res)) of a few natural scrapie isolates identified in sheep, reminiscent of the experimental isolate CH1641 derived from a British natural scrapie case, showed partial molecular similarities to ovine bovine spongiform encephalopathy (BSE). Recent discovery of an atypical form of BSE in cattle, L-type BSE or BASE, suggests that also this form of BSE might have been transmitted to sheep. We studied by Western blot the molecular features of PrP(res) in four "CH1641-like" natural scrapie isolates after transmission in an ovine transgenic model (TgOvPrP4), to see if "CH1641-like" isolates might be linked to L-type BSE. We found less diglycosylated PrP(res) than in classical BSE, but similar glycoform proportions and apparent molecular masses of the usual PrP(res) form (PrP(res) #1) to L-type BSE. However, the "CH1641-like" isolates differed from both L-type and classical BSE by an abundant, C-terminally cleaved PrP(res) product (PrP(res) #2) specifically recognised by a C-terminal antibody (SAF84). Differential immunoprecipitation of PrP(res) #1 and PrP(res) #2 resulted in enrichment in PrP(res) #2, and demonstrated the presence of mono- and diglycosylated PrP(res) products. PrP(res) #2 could not be obtained from several experimental scrapie sources (SSBP1, 79A, Chandler, C506M3) in TgOvPrP4 mice, but was identified in the 87V scrapie strain and, in lower and variable proportions, in 5 of 5 natural scrapie isolates with different molecular features to CH1641. PrP(res) #2 identification provides an additional method for the molecular discrimination of prion strains, and demonstrates differences between "CH1641-like" ovine scrapie and bovine L-type BSE transmitted in an ovine transgenic mouse model.

  19. Satellite broadcasting experiments and in-orbit performance of BSE

    Science.gov (United States)

    Shimoseko, S.; Yamamoto, M.; Kajikawa, M.; Arai, K.

    1981-09-01

    The Japanese medium-scale Broadcasting Satellite for Experimental Purposes (BSE) was launched in April 1978 and placed in a geostationary orbit at 110 deg E longitude. Two transmitters with bandwidths of 50 MHz and 80 MHz were mounted on the BSE transponder to conduct experiments on various television signals; no significant variation in transmission characteristics was observed during the two-year period. Rain attenuation characteristics in the 12 GHz band were studied and a value of 6.6 dB was registered in Owase, one of the most rainy areas in Japan. The strength of the rain scatter wave of the BSE uplink signal was measured to investigate the characteristics between broadcasting satellite uplink and a terrestrial link in the 14 GHz band. Uplink power control, important for the efficient operation of satellite communications systems, was shown to compensate the variations in receiving power due to fluctuations in the beam pointing of the satellite antenna. Routine operations were performed to check the three-axis attitude control, stationkeeping, housekeeping, and the bus equipment. The electrical power, secondary propulsion, thermal control, and communication subsystems were also evaluated. The first operations 1 broadcasting satellite is scheduled to be launched early in 1984.

  20. Application of SIR epidemiological model: new trends

    CERN Document Server

    Rodrigues, Helena Sofia

    2016-01-01

    The simplest epidemiologic model composed by mutually exclusive compartments SIR (susceptible-infected-susceptible) is presented to describe a reality. From health concerns to situations related with marketing, informatics or even sociology, several are the fields that are using this epidemiological model as a first approach to better understand a situation. In this paper, the basic transmission model is analyzed, as well as simple tools that allows us to extract a great deal of information about possible solutions. A set of applications - traditional and new ones - is described to show the importance of this model.

  1. Modeling the variation trends of glacier systems

    Directory of Open Access Journals (Sweden)

    Z. Xie

    2013-01-01

    Full Text Available The basic principles and methods for a functional glacier systems model are introduced and applied for glaciers of Northwest China. When running the model we assume that a glacier system is under steady state conditions in the initial year. The median size of a glacier system is used as representative for the system. The curve of glacier area distribution against elevation is used to compute the increase in equilibrium line altitude (ELA, and the annual glacier ablation is calculated using a global formula a = 1.33(9.66 + ts².⁸⁵ [4, p. 96]. The net mass balance near the ELA under steady state conditions represents the net mass balance of the whole glacier system, and the time required for glacier runoff to return to the initial year level is calculated according to the law of glacier runoff variation, and used to calculate the variation of glacier area. The variation of glacier runoff is modeled according to ablation at the ELA, and the variation of glacier volume is modeled according to the absolute value of the mass balance. The observed changes in surveyed glaciers in China over recent decades were broadly consistent with predictions of the glacier system model. The model therefore offers a reliable method for the prediction of changes in glacier systems in response to changing climate.

  2. Stock Market Trend Analysis Using Hidden Markov Models

    OpenAIRE

    Kavitha, G.; Udhayakumar, A.; D. Nagarajan

    2013-01-01

    Price movements of stock market are not totally random. In fact, what drives the financial market and what pattern financial time series follows have long been the interest that attracts economists, mathematicians and most recently computer scientists [17]. This paper gives an idea about the trend analysis of stock market behaviour using Hidden Markov Model (HMM). The trend once followed over a particular period will sure repeat in future. The one day difference in close value of stocks for a...

  3. Biomechanics trends in modeling and simulation

    CERN Document Server

    Ogden, Ray

    2017-01-01

    The book presents a state-of-the-art overview of biomechanical and mechanobiological modeling and simulation of soft biological tissues. Seven well-known scientists working in that particular field discuss topics such as biomolecules, networks and cells as well as failure, multi-scale, agent-based, bio-chemo-mechanical and finite element models appropriate for computational analysis. Applications include arteries, the heart, vascular stents and valve implants as well as adipose, brain, collagenous and engineered tissues. The mechanics of the whole cell and sub-cellular components as well as the extracellular matrix structure and mechanotransduction are described. In particular, the formation and remodeling of stress fibers, cytoskeletal contractility, cell adhesion and the mechanical regulation of fibroblast migration in healing myocardial infarcts are discussed. The essential ingredients of continuum mechanics are provided. Constitutive models of fiber-reinforced materials with an emphasis on arterial walls ...

  4. Trends in modeling Biomedical Complex Systems

    Directory of Open Access Journals (Sweden)

    Remondini Daniel

    2009-10-01

    Full Text Available Abstract In this paper we provide an introduction to the techniques for multi-scale complex biological systems, from the single bio-molecule to the cell, combining theoretical modeling, experiments, informatics tools and technologies suitable for biological and biomedical research, which are becoming increasingly multidisciplinary, multidimensional and information-driven. The most important concepts on mathematical modeling methodologies and statistical inference, bioinformatics and standards tools to investigate complex biomedical systems are discussed and the prominent literature useful to both the practitioner and the theoretician are presented.

  5. Modeling variability and trends in pesticide concentrations in streams

    Science.gov (United States)

    Vecchia, A.V.; Martin, J.D.; Gilliom, R.J.

    2008-01-01

    A parametric regression model was developed for assessing the variability and long-term trends in pesticide concentrations in streams. The dependent variable is the logarithm of pesticide concentration and the explanatory variables are a seasonal wave, which represents the seasonal variability of concentration in response to seasonal application rates; a streamflow anomaly, which is the deviation of concurrent daily streamflow from average conditions for the previous 30 days; and a trend, which represents long-term (inter-annual) changes in concentration. Application of the model to selected herbicides and insecticides in four diverse streams indicated the model is robust with respect to pesticide type, stream location, and the degree of censoring (proportion of nondetections). An automatic model fitting and selection procedure for the seasonal wave and trend components was found to perform well for the datasets analyzed. Artificial censoring scenarios were used in a Monte Carlo simulation analysis to show that the fitted trends were unbiased and the approximate p-values were accurate for as few as 10 uncensored concentrations during a three-year period, assuming a sampling frequency of 15 samples per year. Trend estimates for the full model were compared with a model without the streamflow anomaly and a model in which the seasonality was modeled using standard trigonometric functions, rather than seasonal application rates. Exclusion of the streamflow anomaly resulted in substantial increases in the mean-squared error and decreases in power for detecting trends. Incorrectly modeling the seasonal structure of the concentration data resulted in substantial estimation bias and moderate increases in mean-squared error and decreases in power. ?? 2008 American Water Resources Association.

  6. Entropy Based Modelling for Estimating Demographic Trends.

    Directory of Open Access Journals (Sweden)

    Guoqi Li

    Full Text Available In this paper, an entropy-based method is proposed to forecast the demographical changes of countries. We formulate the estimation of future demographical profiles as a constrained optimization problem, anchored on the empirically validated assumption that the entropy of age distribution is increasing in time. The procedure of the proposed method involves three stages, namely: 1 Prediction of the age distribution of a country's population based on an "age-structured population model"; 2 Estimation the age distribution of each individual household size with an entropy-based formulation based on an "individual household size model"; and 3 Estimation the number of each household size based on a "total household size model". The last stage is achieved by projecting the age distribution of the country's population (obtained in stage 1 onto the age distributions of individual household sizes (obtained in stage 2. The effectiveness of the proposed method is demonstrated by feeding real world data, and it is general and versatile enough to be extended to other time dependent demographic variables.

  7. Trend stationarity in the I(2) cointegration model

    DEFF Research Database (Denmark)

    Rahbek, Anders; Kongsted, Hans Christian; Jørgensen, Clara

    1999-01-01

    A vector autoregressive model for I(2) processes which allows for trend-stationary components and restricts the deterministic part of the process to be at most linear is defined. A two-step statistical analysis of the model is derived. The joint test of I(1) and I(2) cointegrating ranks is shown...

  8. Sheep prions with molecular properties intermediate between classical scrapie, BSE and CH1641-scrapie

    OpenAIRE

    Langeveld, Jan P. M.; Jacobs, Jorg G; Erkens, Jo H.F.; Baron, Thierry; Andreoletti, Olivier; Yokoyama, Takahashi; Van Keulen, Lucien J. M.; van Zijderveld, Fred G.; Davidse, Aart; Hope, Jim; Tang, Yue; Bossers, Alex

    2014-01-01

    Efforts to differentiate bovine spongiform encephalopathy (BSE) from scrapie in prion infected sheep have resulted in effective methods to decide about the absence of BSE. In rare instances uncertainties remain due to assumptions that BSE, classical scrapie and CH1641–a rare scrapie variant–could occur as mixtures. In field samples including those from fallen stock, triplex Western blotting analyses of variations in the molecular properties of the proteinase K resistant part of the disease‑as...

  9. Cointegration between trends and their estimators in state space models and CVAR models

    DEFF Research Database (Denmark)

    Johansen, Søren; Tabor, Morten Nyboe

    2017-01-01

    In a linear state space model Y(t)=BT(t) e(t), we investigate if the unobserved trend, T(t), cointegrates with the predicted trend, E(t), and with the estimated predicted trend, in the sense that the spreads are stationary. We find that this result holds for the spread B......(T(t)-E(t)) and the estimated spread. For the spread between the trend and the estimated trend, T(t)-E(t), however, cointegration depends on the identification of B. The same results are found, if the observations Y(t), from the state space model are analysed using a cointegrated vector autoregressive model, where the trend...... is defined as the common trend. Finally, we investigate cointegration between the spread between trends and their estimators based on the two models, and find the same results. We illustrate with two examples and confirm the results by a small simulation study....

  10. Evaluation of the effectiveness of selected measures against bovine spongiform encephalopathy (BSE) in Switzerland by use of the basic reproduction ratio R0.

    Science.gov (United States)

    Schwermer, Heinzpeter; Brülisauer, Franz; De Koeijer, Aline; Heim, Dagmar

    2007-01-01

    The effectiveness of two measures against Bovine Spongiform Encephalopathy (BSE), the compulsory processing of animal by products to meat and bone meal (MBM) at 133 degrees C under 3 bars of pressure for 20 minutes in February 1993 and the exclusion of fallen stock, heads with eyes and spinal cord of cattle older than 30 month from MBM production in April 1996, was evaluated in a process model. The transmission of BSE by calculation of the basic reproduction ratio R0 was modelled. The results were verified by use of a cohort model, based on observed surveillance data. Prior to 1990, before the ban of feeding MBM to ruminants, R0, as calculated in the process model, was above 1, coherent with a slowly progressing BSE epidemic. Since 1991, values of R0 were low at 0.06. The corresponding R0 values derived from the cohort model were higher, the lowest value 0.13 calculated for 1996. Given such low R0 values, the epidemic should have died out. Additionally, no influence of the two measures was obvious at that time given the low level of R0. The discrepancy between the results of the two models is evidence for a dependency of the BSE epidemic from an infection source not considered in the process model. This infection source is most likely importation of feed ingredients and MBM.

  11. Statistical analysis of strait time index and a simple model for trend and trend reversal

    Science.gov (United States)

    Chen, Kan; Jayaprakash, C.

    2003-06-01

    We analyze the daily closing prices of the Strait Time Index (STI) as well as the individual stocks traded in Singapore's stock market from 1988 to 2001. We find that the Hurst exponent is approximately 0.6 for both the STI and individual stocks, while the normal correlation functions show the random walk exponent of 0.5. We also investigate the conditional average of the price change in an interval of length T given the price change in the previous interval. We find strong correlations for price changes larger than a threshold value proportional to T; this indicates that there is no uniform crossover to Gaussian behavior. A simple model based on short-time trend and trend reversal is constructed. We show that the model exhibits statistical properties and market swings similar to those of the real market.

  12. Atypical BSE in Germany--proof of transmissibility and biochemical characterization.

    Science.gov (United States)

    Buschmann, A; Gretzschel, A; Biacabe, A-G; Schiebel, K; Corona, C; Hoffmann, C; Eiden, M; Baron, T; Casalone, C; Groschup, Martin H

    2006-10-31

    Intensive active surveillance has uncovered two atypical German BSE cases in older cattle which resemble the two different atypical BSE phenotypes that have recently been described in France (designated H-type) and Italy (designated L-type or BASE). The H-type is characterized by a significantly higher molecular size, but a conventional glycopattern of the proteinase K treated abnormal prion protein (PrP(Sc)), while the L-type PrP(Sc) has only a slightly lower molecular size and a distinctly different glycopattern. In this paper we describe the successful transmission of both German atypical BSE cases to transgenic mice overexpressing bovine PrP(C). Upon challenge with the L-type, these mice developed BSE after a substantially shorter incubation period than any classical BSE transmission using these mice to date. In contrast, the incubation period was distinctly prolonged when these mice were challenged with the H-type. PrP(Sc) accumulated in the brains of these mice were of the same atypical BSE type that had been used for the transmission. These atypical cases suggest the possible existence of sporadic BSE cases in bovines. It is thus feasible that the BSE epidemic in the UK could have also been initiated by an intraspecies transmission from a sporadic BSE case.

  13. Uncertainty beyond probabilities of BSE: appraisals predicting worry and coping strategies in the Canadian public.

    Science.gov (United States)

    Markon, Marie-Pierre L; Lemyre, Louise; Krewski, Daniel

    2011-01-01

    The impact of bovine spongiform encephalopathy (BSE) is not limited to the infection with the BSE agent but also affects psychosocial responses, such as worry and loss of confidence in public authorities. It was shown in past crises that these reactions depended upon the way the event was perceived by the public. Understanding the nature of the perceptions of BSE is therefore of great importance for risk management in all phases of the risk, including the period before the onset of a crisis, when BSE is still only a pending threat to human health. This study analyzed data from a representative national survey of Canadians (n = 1,517) on the perceived risk of prion diseases. Factor analysis revealed emerging dimensions of BSE appraisals and regression analysis identified variables that predicted worry and coping strategies. Results yielded three significant factors, each relating differently to reactions to BSE: (1) Perceived impact, which combined perceived risk for health and likelihood of occurrence of BSE crises, was the main predictor of worry about eating tainted beef; (2) perceived mastery, consisting of personal knowledge and control, predicted taking action to avoid the disease; and (3) perceived intricacy, composed of perceived complexity and uncertainty, uniquely predicted trying to ignore BSE-related risks. Further regression analysis and analysis of variance exposed a moderating role of perceived intricacy on the relationship between perceived impact of BSE crises and worry. The implications of these findings for risk communication and management are described.

  14. Poultry, pig and the risk of BSE following the feed ban in France--a spatial analysis.

    Science.gov (United States)

    Abrial, David; Calavas, Didier; Jarrige, Nathalie; Ducrot, Christian

    2005-01-01

    A spatial analysis was carried out in order to analyse the reason why the risk of Bovine Spongiform Encephalopathy (BSE) was spatially heterogeneous in France, during the period following the feed ban of Meat and Bone Meal to cattle. The hypothesis of cross-contamination between cattle feedstuff and monogastric feedstuff, which was strongly suggested from previous investigations, was assessed, with the assumption that the higher the pig or poultry density is in a given area, the higher the risk of cross-contamination and cattle infection might be. The data concerned the 467 BSE cases born in France after the ban of meat and bone meal (July 1990) and detected between July 1st, 2001 and December 31, 2003, when the surveillance system was optimal and not spatially biased. The disease mapping models were elaborated with the Bayesian graphical modelling methods and based on a Poisson distribution with spatial smoothing (hierarchical approach) and covariates. The parameters were estimated by a Markov Chain Monte Carlo simulation method. The main result was that the poultry density did not significantly influence the risk of BSE whereas the pig density was significantly associated with an increase in the risk of 2.4% per 10 000 pigs. The areas with a significant pig effect were located in regions with a high pig density as well as a high ratio of pigs to cattle. Despite the absence of a global effect of poultry density on the BSE risk, some areas had a significant poultry effect and the risk was better explained in some others when considering both pig and poultry densities. These findings were in agreement with the hypothesis of cross-contamination, which could take place at the feedstuff factory, during the shipment of food or on the farm. Further studies are needed to more precisely explore how the cross-contamination happened.

  15. Unit root modeling for trending stock market series

    Directory of Open Access Journals (Sweden)

    Afees A. Salisu

    2016-06-01

    Full Text Available In this paper, we examine how the unit root for stock market series should be modeled. We employ the Narayan and Liu (2015 trend GARCH-based unit root and its variants in order to more carefully capture the inherent statistical behavior of the series. We utilize daily, weekly and monthly data covering nineteen countries across the regions of America, Asia and Europe. We find that the nature of data frequency matters for unit root testing when dealing with stock market data. Our evidence also suggests that stock market data is better modeled in the presence of structural breaks, conditional heteroscedasticity and time trend.

  16. Bankruptcy Risk in IFRS Era. Case Study on BSE Companies

    Directory of Open Access Journals (Sweden)

    Valentin BURCA

    2013-12-01

    Full Text Available The path of international accounting convergence is, unanimously accepted by all decision makers of the international financial reporting environment, as being the best solution towards reducing differences in international accounting. The idea of core standards is embraced by our country, too, the proof being the last legislative changes in Romanian accounting framework. This study aims to highlight a small part of the economic consequences of the decision to extend the mandatory use of IFRS standards to the statutory financial statements, also. More exactly we will underline the changes registered at the level of bankruptcy risk measureson a samples of companies listed on BSE.

  17. Recent trends in specialty pharma business model

    Directory of Open Access Journals (Sweden)

    Mannching Sherry Ku

    2015-12-01

    Full Text Available The recent rise of specialty pharma is attributed to its flexible, versatile, and open business model while the traditional big pharma is facing a challenging time with patent cliff, generic threat, and low research and development (R&D productivity. These multinational pharmaceutical companies, facing a difficult time, have been systematically externalizing R&D and some even establish their own corporate venture capital so as to diversify with more shots on goal, with the hope of achieving a higher success rate in their compound pipeline. Biologics and clinical Phase II proof-of-concept (POC compounds are the preferred licensing and collaboration targets. Biologics enjoys a high success rate with a low generic biosimilar threat, while the need is high for clinical Phase II POC compounds, due to its high attrition/low success rate. Repurposing of big pharma leftover compounds is a popular strategy but with limitations. Most old compounds come with baggage either in lackluster clinical performance or short in patent life. Orphan drugs is another area which has gained popularity in recent years. The shorter and less costly regulatory pathway provides incentives, especially for smaller specialty pharma. However, clinical studies on orphan drugs require a large network of clinical operations in many countries in order to recruit enough patients. Big pharma is also working on orphan drugs starting with a small indication, with the hope of expanding the indication into a blockbuster status. Specialty medicine, including orphan drugs, has become the growth engine in the pharmaceutical industry worldwide. Big pharma is also keen on in-licensing technology or projects from specialty pharma to extend product life cycles, in order to protect their blockbuster drug franchises. Ample opportunities exist for smaller players, even in the emerging countries, to collaborate with multinational pharmaceutical companies provided that the technology platforms or

  18. Recent trends in specialty pharma business model.

    Science.gov (United States)

    Ku, Mannching Sherry

    2015-12-01

    The recent rise of specialty pharma is attributed to its flexible, versatile, and open business model while the traditional big pharma is facing a challenging time with patent cliff, generic threat, and low research and development (R&D) productivity. These multinational pharmaceutical companies, facing a difficult time, have been systematically externalizing R&D and some even establish their own corporate venture capital so as to diversify with more shots on goal, with the hope of achieving a higher success rate in their compound pipeline. Biologics and clinical Phase II proof-of-concept (POC) compounds are the preferred licensing and collaboration targets. Biologics enjoys a high success rate with a low generic biosimilar threat, while the need is high for clinical Phase II POC compounds, due to its high attrition/low success rate. Repurposing of big pharma leftover compounds is a popular strategy but with limitations. Most old compounds come with baggage either in lackluster clinical performance or short in patent life. Orphan drugs is another area which has gained popularity in recent years. The shorter and less costly regulatory pathway provides incentives, especially for smaller specialty pharma. However, clinical studies on orphan drugs require a large network of clinical operations in many countries in order to recruit enough patients. Big pharma is also working on orphan drugs starting with a small indication, with the hope of expanding the indication into a blockbuster status. Specialty medicine, including orphan drugs, has become the growth engine in the pharmaceutical industry worldwide. Big pharma is also keen on in-licensing technology or projects from specialty pharma to extend product life cycles, in order to protect their blockbuster drug franchises. Ample opportunities exist for smaller players, even in the emerging countries, to collaborate with multinational pharmaceutical companies provided that the technology platforms or specialty medicinal

  19. METHODOLOGICAL APPROACH AND MODEL ANALYSIS FOR IDENTIFICATION OF TOURIST TRENDS

    Directory of Open Access Journals (Sweden)

    Neven Šerić

    2015-06-01

    Full Text Available The draw and diversity of the destination’s offer is an antecedent of the tourism visits growth. The destination supply differentiation is carried through new, specialised tourism products. The usual approach consists of forming specialised tourism products in accordance with the existing tourism destination image. Another approach, prevalent in practice of developed tourism destinations is based on innovating the destination supply through accordance with the global tourism trends. For this particular purpose, it is advisable to choose a monitoring and analysis method of tourism trends. The goal is to determine actual trends governing target markets, differentiating whims from trends during the tourism preseason. When considering the return on investment, modifying the destination’s tourism offer on the basis of a tourism whim is a risky endeavour, indeed. Adapting the destination’s supply to tourism whims can result in a shifted image, one that is unable to ensure a long term interest and tourist vacation growth. With regard to tourism trend research and based on the research conducted, an advisable model for evaluating tourism phenomena is proposed, one that determines whether tourism phenomena is a tourism trend or a tourism whim.

  20. Biological and biochemical characterization of L-type-like bovine spongiform encephalopathy (BSE) detected in Japanese black beef cattle

    OpenAIRE

    2008-01-01

    A case of L-type-like atypical bovine spongiform encephalopathy was detected in 14-year-old Japanese black beef cattle (BSE/JP24). To clarify the biological and biochemical properties of the prion in BSE/JP24, we performed a transmission study with wild-type mice and bovinized transgenic mice (TgBoPrP). The BSE/JP24 prion was transmitted to TgBoPrP mice with the incubation period of 199.7 ± 3.4 days, which was shorter than that of classical BSE (C-BSE) (223.5 ± 13.5 days). Further, C-BSE was ...

  1. Modelling of trends in Twitter using retweet graph dynamics

    NARCIS (Netherlands)

    Ten Thij, Marijn; Ouboter, Tanneke; Worm, Daniël; Litvak, Nelly; Berg, van den Hans; Bhulai, Sandjai; Bonata, Anthony; Chung, Fan Chung; Pralat, Pawel

    2014-01-01

    In this paper we model user behaviour in Twitter to capture the emergence of trending topics. For this purpose, we first extensively analyse tweet datasets of several different events. In particular, for these datasets, we construct and investigate the retweet graphs. We find that the retweet graph

  2. Biological and biochemical characterization of L-type-like bovine spongiform encephalopathy (BSE) detected in Japanese black beef cattle.

    Science.gov (United States)

    Masujin, Kentaro; Shu, Yujing; Yamakawa, Yoshio; Hagiwara, Ken'ichi; Sata, Tetsutaro; Matsuura, Yuichi; Iwamaru, Yoshifumi; Imamura, Morikazu; Okada, Hiroyuki; Mohri, Shirou; Yokoyama, Takashi

    2008-01-01

    A case of L-type-like atypical bovine spongiform encephalopathy was detected in 14-year-old Japanese black beef cattle (BSE/JP24). To clarify the biological and biochemical properties of the prion in BSE/JP24, we performed a transmission study with wild-type mice and bovinized transgenic mice (TgBoPrP). The BSE/JP24 prion was transmitted to TgBoPrP mice with the incubation period of 199.7 +/- 3.4 days, which was shorter than that of classical BSE (C-BSE) (223.5 +/- 13.5 days). Further, C-BSE was transmitted to wild-type mice with the incubation period of about 409 days, whereas BSE/JP24 prion inoculated mice showed no clinical signs up to 649 days. Severe vacuolation and a widespread and uniform distribution of PrP(Sc) were pathologically observed in the brain of BSE/JP24 prion affected TgBoPrP mice. The molecular weight and glycoform ratio of PrP(Sc) in BSE/JP24 were different from those in C-BSE, and PrP(Sc) in BSE/JP24 exhibited weaker proteinase K resistance than that in C-BSE. These findings revealed that the BSE/JP24 prion has distinct biological and biochemical properties reported for that of C-BSE. Interestingly, a shorter incubation period was observed at the subsequent passage of the BSE/JP24 prion to TgBoPrP mice (152.2 +/- 3.1 days). This result implies that BSE/JP24 prion has newly emerged and showed the possibility that L-type BSE prion might be classified into multiple strains.

  3. CNS histopathology on bovines with clinical suspicion of BSE in Denmark 2001 to 2011

    DEFF Research Database (Denmark)

    Jensen, Tim Kåre

    During2001 to 2011 a total of 195 bovines were submitted to the instutute with clinical suspicion of having BSE. In two cases BSE was confirmed. The most common differential diagnosis was listeriosis, found in 54% of the cases. Listeriosis was characterized by multifocal, necrotizing, non...

  4. Quantifying BSE control by calculating the basic reproduction ratio R0 for the infection among cattle

    NARCIS (Netherlands)

    Koeijer, de A.A.; Heesterbeek, H.; Schreuder, B.E.C.; Oberthur, R.; Wilesmith, J.; Roermund, van H.J.W.; Jong, de M.C.M.

    2004-01-01

    The safety of using meat and bone meal (MBM) in mammal feed was studied in view of BSE, by quantifying the risk of BSE transmission through different infection routes. This risk is embodied in the basic reproduction ratio R(0) of the infection, i.e. the average number of new infections induced by on

  5. Quantifying BSE control by calculating the basic reproduction ratio R0 for the infection among cattle

    NARCIS (Netherlands)

    Koeijer, A. de; Heesterbeek, J.A.P.; Schreuder, B.; Oberthür, R.; Wilesmith, J.; Roermund, H. van; Jong, Mart de

    2004-01-01

    The safety of using meat and bone meal (MBM) in mammal feed was studied in view of BSE, by quantifying the risk of BSE transmission through different infection routes. This risk is embodied in the basic reproduction ratio R 0 of the infection, i.e. the average number of new infections induced by one

  6. A single step multiplex immunofluorometric assay for differential diagnosis of BSE and scrapie

    NARCIS (Netherlands)

    Tang, Y.; Thorne, J.; Whatling, K.L.; Jacobs, J.G.; Langeveld, J.P.M.; Sauer, M.

    2010-01-01

    Although there is no evidence that the European sheep population has been infected with bovine spongiform encephalopathy (BSE), distinguishing this from scrapie is paramount, given the association between BSE exposure and the human transmissible spongiform encephalopathy (TSE), variant Creutzfeldt–J

  7. PRNP promoter polymorphisms are associated with BSE susceptibility in Swiss and German cattle

    Directory of Open Access Journals (Sweden)

    Ziegler Ute

    2007-04-01

    Full Text Available Abstract Background Non-synonymous polymorphisms within the prion protein gene (PRNP influence the susceptibility and incubation time for transmissible spongiform encephalopathies (TSE in some species such as sheep and humans. In cattle, none of the known polymorphisms within the PRNP coding region has a major influence on susceptibility to bovine spongiform encephalopathy (BSE. Recently, however, we demonstrated an association between susceptibility to BSE and a 23 bp insertion/deletion (indel polymorphism and a 12 bp indel polymorphism within the putative PRNP promoter region using 43 German BSE cases and 48 German control cattle. The objective of this study was to extend this work by including a larger number of BSE cases and control cattle of German and Swiss origin. Results Allele, genotype and haplotype frequencies of the two indel polymorphisms were determined in 449 BSE cattle and 431 unaffected cattle from Switzerland and Germany including all 43 German BSE and 16 German control animals from the original study. When breeds with similar allele and genotype distributions were compared, the 23 bp indel polymorphism again showed a significant association with susceptibility to BSE. However, some additional breed-specific allele and genotype distributions were identified, mainly related to the Brown breeds. Conclusion Our study corroborated earlier findings that polymorphisms in the PRNP promoter region have an influence on susceptibility to BSE. However, breed-specific differences exist that need to be accounted for when analyzing such data.

  8. Modelling surface run-off and trends analysis over India

    Science.gov (United States)

    Gupta, P. K.; Chauhan, S.; Oza, M. P.

    2016-08-01

    The present study is mainly concerned with detecting the trend of run-off over the mainland of India, during a time period of 35 years, from 1971-2005 (May-October). Rainfall, soil texture, land cover types, slope, etc., were processed and run-off modelling was done using the Natural Resources Conservation Service (NRCS) model with modifications and cell size of 5×5 km. The slope and antecedent moisture corrections were incorporated in the existing model. Trend analysis of estimated run-off was done by taking into account different analysis windows such as cell, medium and major river basins, meteorological sub-divisions and elevation zones across India. It was estimated that out of the average 1012.5 mm of rainfall over India (considering the study period of 35 years), 33.8% got converted to surface run-off. An exponential model was developed between the rainfall and the run-off that predicted the run-off with an R 2 of 0.97 and RMSE of 8.31 mm. The run-off trend analysed using the Mann-Kendall test revealed that a significant pattern exists in 22 medium, two major river basins and three meteorological sub-divisions, while there was no evidence of a statistically significant trend in the elevation zones. Among the medium river basins, the highest positive rate of change in the run-off was observed in the Kameng basin (13.6 mm/yr), while the highest negative trend was observed in the Tista upstream basin (-21.4 mm/yr). Changes in run-off provide valuable information for understanding the region's sensitivity to climatic variability.

  9. Modelling surface run-off and trends analysis over India

    Indian Academy of Sciences (India)

    P K Gupta; S Chauhan; M P Oza

    2016-08-01

    The present study is mainly concerned with detecting the trend of run-off over the mainland of India, during a time period of 35 years, from 1971–2005 May–October). Rainfall, soil texture, land cover types, slope, etc., were processed and run-off modelling was done using the Natural Resources ConservationService (NRCS) model with modifications and cell size of 5×5 km. The slope and antecedent moisture corrections were incorporated in the existing model. Trend analysis of estimated run-off was done by taking into account different analysis windows such as cell, medium and major river basins, meteorologicalsub-divisions and elevation zones across India. It was estimated that out of the average 1012.5 mm of rainfall over India (considering the study period of 35 years), 33.8% got converted to surface run-off. An exponential model was developed between the rainfall and the run-off that predicted the run-off with an $R^2$ of 0.97 and RMSE of 8.31 mm. The run-off trend analysed using the Mann–Kendall test revealed that a significant pattern exists in 22 medium, two major river basins and three meteorological subdivisions, while there was no evidence of a statistically significant trend in the elevation zones. Among the medium river basins, the highest positive rate of change in the run-off was observed in the Kameng basin (13.6 mm/yr), while the highest negative trend was observed in the Tista upstream basin (−21.4 mm/yr). Changes in run-off provide valuable information for understanding the region’s sensitivity to climatic variability.

  10. Identification of a heritable polymorphism in bovine PRNP associated with genetic transmissible spongiform encephalopathy: evidence of heritable BSE.

    Directory of Open Access Journals (Sweden)

    Eric M Nicholson

    Full Text Available BACKGROUND: Bovine spongiform encephalopathy (BSE is a transmissible spongiform encephalopathy (TSE of cattle. Classical BSE is associated with ingestion of BSE-contaminated feedstuffs. H- and L-type BSE, collectively known as atypical BSE, differ from classical BSE by displaying a different disease phenotype and they have not been linked to the consumption of contaminated feed. Interestingly, the 2006 US H-type atypical BSE animal had a polymorphism at codon 211 of the bovine prion gene resulting in a glutamic acid to lysine substitution (E211K. This substitution is analogous a human polymorphism associated with the most prevalent form of heritable TSE in humans, and it is considered to have caused BSE in the 2006 US atypical BSE animal. In order to determine if this amino acid change is a heritable trait in cattle, we sequenced the prion alleles of the only known offspring of this animal, a 2-year-old heifer. PRINCIPAL FINDINGS: Sequence analysis revealed that both the 2006 US atypical BSE animal and its 2-year-old heifer were heterozygous at bovine prion gene nucleotides 631 through 633 for GAA (glutamic acid and AAA (lysine. Both animals carry the E211K polymorphism, indicating that the allele is heritable and may persist within the cattle population. CONCLUSIONS: This is the first evidence that the E211K polymorphism is a germline polymorphism, not a somatic mutation, suggesting BSE may be transmitted genetically in cattle. In the event that E211K proves to result in a genetic form of BSE, this would be the first indication that all 3 etiologic forms of TSEs (spontaneous, hereditary, and infectious are present in a non-human species. Atypical BSE arising as both genetic and spontaneous disease, in the context of reports that at least some forms of atypical BSE can convert to classical BSE in mice, suggests a cattle origin for classical BSE.

  11. Dynamic Model Predicting Overweight, Obesity, and Extreme Obesity Prevalence Trends

    Science.gov (United States)

    Thomas, Diana M.; Weedermann, Marion; Fuemmeler, Bernard F.; Martin, Corby K.; Dhurandhar, Nikhil V.; Bredlau, Carl; Heymsfield, Steven B.; Ravussin, Eric; Bouchard, Claude

    2013-01-01

    Objective Obesity prevalence in the United States (US) appears to be leveling, but the reasons behind the plateau remain unknown. Mechanistic insights can be provided from a mathematical model. The objective of this study is to model known multiple population parameters associated with changes in body mass index (BMI) classes and to establish conditions under which obesity prevalence will plateau. Design and Methods A differential equation system was developed that predicts population-wide obesity prevalence trends. The model considers both social and non-social influences on weight gain, incorporates other known parameters affecting obesity trends, and allows for country specific population growth. Results The dynamic model predicts that: obesity prevalence is a function of birth rate and the probability of being born in an obesogenic environment; obesity prevalence will plateau independent of current prevention strategies; and the US prevalence of obesity, overweight, and extreme obesity will plateau by about 2030 at 28%, 32%, and 9%, respectively. Conclusions The US prevalence of obesity is stabilizing and will plateau, independent of current preventative strategies. This trend has important implications in accurately evaluating the impact of various anti-obesity strategies aimed at reducing obesity prevalence. PMID:23804487

  12. Modeling the Influence of Hemispheric Transport on Trends in ...

    Science.gov (United States)

    We describe the development and application of the hemispheric version of the CMAQ to examine the influence of long-range pollutant transport on trends in surface level O3 distributions. The WRF-CMAQ model is expanded to hemispheric scales and multi-decadal model simulations were recently performed for the period spanning 1990-2010 to examine changes in hemispheric air pollution resulting from changes in emissions over this period. Simulated trends in ozone and precursor species concentrations across the U.S. and the northern hemisphere over the past two decades are compared with those inferred from available measurements during this period. Additionally, the decoupled direct method (DDM) in CMAQ is used to estimate the sensitivity of O3 to emissions from different source regions across the northern hemisphere. The seasonal variations in source region contributions to background O3 is then estimated from these sensitivity calculations and will be discussed. A reduced form model combining these source region sensitivities estimated from DDM with the multi-decadal simulations of O3 distributions and emissions trends, is then developed to characterize the changing contributions of different source regions to background O3 levels across North America. The National Exposure Research Laboratory (NERL) Computational Exposure Division (CED) develops and evaluates data, decision-support tools, and models to be applied to media-specific or receptor-specific problem areas

  13. Evaluation of two sets of immunohistochemical and Western blot confirmatory methods in the detection of typical and atypical BSE cases

    Science.gov (United States)

    Aims: To compare the ability of the Italian and the U.S. bovine spongiform encephalopathy (BSE) confirmatory protocols in the detection of classical (C-) and atypical - low (L-) and high (H-) type- BSE forms. Methods and Results: Obex samples from U.S. and Italian C-type BSE cases, a U.S. H-type and...

  14. Emerging Trends and Statistical Analysis in Computational Modeling in Agriculture

    Directory of Open Access Journals (Sweden)

    Sunil Kumar

    2015-03-01

    Full Text Available In this paper the authors have tried to describe emerging trend in computational modelling used in the sphere of agriculture. Agricultural computational modelling with the use of intelligence techniques for computing the agricultural output by providing minimum input data to lessen the time through cutting down the multi locational field trials and also the labours and other inputs is getting momentum. Development of locally suitable integrated farming systems (IFS is the utmost need of the day, particularly in India where about 95% farms are under small and marginal holding size. Optimization of the size and number of the various enterprises to the desired IFS model for a particular set of agro-climate is essential components of the research to sustain the agricultural productivity for not only filling the stomach of the bourgeoning population of the country, but also to enhance the nutritional security and farms return for quality life. Review of literature pertaining to emerging trends in computational modelling applied in field of agriculture is done and described below for the purpose of understanding its trends mechanism behavior and its applications. Computational modelling is increasingly effective for designing and analysis of the system. Computa-tional modelling is an important tool to analyses the effect of different scenarios of climate and management options on the farming systems and its interaction among themselves. Further, authors have also highlighted the applications of computational modeling in integrated farming system, crops, weather, soil, climate, horticulture and statistical used in agriculture which can show the path to the agriculture researcher and rural farming community to replace some of the traditional techniques.

  15. BSE, feed and cattle in Switzerland: is there a spatial relation?

    Science.gov (United States)

    Schwermer, Heinzpeter; Forster, Katharina; Brülisauer, Franz; Chaubert, Claude; Heim, Dagmar

    2007-01-01

    Cross-contamination of cattle feed with meat and bone meal (MBM) allowed in feed for other species is regarded as the current hypothesis for the infection pathway of Bovine Spongiform Encephalopathy (BSE) cases occurring after the implementation of a ban on feeding MBM to cattle. This study was aimed at establishing a spatial relation between BSE cases in Switzerland and the findings of MBM in cattle feed. A cluster analysis and a cohort study were performed. Two hundred sixteen BSE cases born after December 1990 and detected until August 1st 2005, screening data of 504 feed producers between 1996 and 2001 and population data from the Swiss 2001 cattle census were included. The cluster analysis showed feed producer, positive for MBM contaminations in cattle feed, as possible cluster centres for BSE cases. In the cohort study, farms within a radius of 2 and 10 km around positive feed producers showed significantly higher odds to have a BSE case than the control group. The odds ratio and its 95% confidence interval were 2.23 (1.26-3.93) for the 2 km radius and 1.38 (1-1.9) for the 10 km radius. The results provide evidence for a spatial relation between cross-contamination and BSE occurrence. These findings support the hypothesis of cross-contamination to be an important route for BSE transmission after a feed ban.

  16. Experimental challenge of cattle with German atypical bovine spongiform encephalopathy (BSE) isolates.

    Science.gov (United States)

    Balkema-Buschmann, A; Ziegler, U; McIntyre, L; Keller, M; Hoffmann, C; Rogers, R; Hills, B; Groschup, M H

    2011-01-01

    For almost two decades after the discovery of the first bovine spongiform encephalopathy (BSE) case, it was generally accepted that only one BSE strain existed globally. However, in 2004, two novel BSE forms (L-type and H-type) were separately identified in two different European Member States, forms that differed from the classical (C-type) form by their biochemical properties and by the pattern of PrP(Sc) deposition as determined by immunohistochemistry (IHC). 60 atypical BSE cases have been identified worldwide as of November 2010, including one H- and one L-type BSE case each in Germany. However, it was not known whether the biological properties (pathogenesis and agent distribution, as well as transmissibility to other species) of these novel forms were the same as in classical BSE cases. Eleven calves were thus challenged intracranially, five with the German H-type and six with German L-type BSE cases. The experimental design and the clinical studies, followed by laboratory testing, are described in this manuscript.

  17. PET-blot analysis contributes to BSE strain recognition in C57Bl/6 mice.

    Science.gov (United States)

    Lezmi, Stéphane; Bencsik, Anna; Baron, Thierry

    2006-10-01

    Identification of the strain of agent responsible for bovine spongiform encephalopathy (BSE) can be made histologically through the analysis of both distribution and intensity of brain vacuolar lesions after BSE transmission to mouse. Another useful way to distinguish the BSE agent from other prion strains is the study of the distribution of the abnormal prion protein (PrP(res)). For that purpose, paraffin-embedded tissue blot (PET-blot) method was applied on brains from C57Bl/6 mice infected with cattle BSE, experimental sheep BSE, or feline spongiform encephalopathy (FSE) from a cheetah. PrP(res) distribution was comparable, whichever of the three BSE agent sources was considered and was distinct from the PrP(res) distribution in C57Bl/6 mice inoculated with a French scrapie isolate or with a mouse-adapted scrapie strain (C506M3). These data confirm a common origin of infectious agent responsible for the British and French cattle BSE. They also indicate that PET-blot method appears as a precise complementary tool in prion strain studies because it offers easy and quick assessment of the PrP(res) mapping. Advantages and limits of the PET-blot method are discussed and compared with other established and validated methods of strain typing.

  18. BSE infectivity in jejunum, ileum and ileocaecal junction of incubating cattle

    Directory of Open Access Journals (Sweden)

    Hoffmann Christine

    2011-02-01

    Full Text Available Abstract To establish bovine spongiform encephalopathy (BSE public health protection measures it is important to precisely define the cattle tissues considered as specified risk materials (SRM. To date, in pre-clinical BSE infected cattle, no evidence of the BSE agent had been found in the gut outside of the ileal Peyer's Patches. This study was undertaken to determine when and where the pathological prion protein (PrPSc and/or BSE infectivity can be found in the small intestine of cattle 4 to 6 months of age, orally challenged with BSE. Samples of the jejunum, the ileum and the ileocaecal junction from 46 BSE infected cattle, culled from 1 up to 44 months post infection (mpi were examined by immunohistochemistry. Samples from cattle 8 mpi to 20 mpi were additionally studied by PTA Western blot, rapid tests, and by mouse (TgbovXV bioassay. In doing so nearly all of the cattle, from 4 up to 44 mpi, had detectable amounts of PrPSc and/or infectivity in the distal ileum. In the distal ileum clear time-dependent variations were visible concerning the amount of PrPSc, the tissue structures affected, and the cells involved. BSE infectivity was found not only in the ileum and ileocaecal junction but also in the jejunum. The systematic approach of this study provides new data for qualitative and quantitative risk assessments and allows defining bovine SRM more precisely.

  19. Light tetraquarks and mesons in a DSE/BSE approach

    Energy Technology Data Exchange (ETDEWEB)

    Heupel, Walter

    2015-07-01

    Bound states and their properties are an inherent non-perturbative feature of QCD. Moreover, QCD is a confining theory so that instead of the elementary quarks and gluons themselves, only colourless bound states formed of these elementary particles are directly measurable. One non-perturbative framework to describe QCD are the Dyson-Schwinger equations, which interrelate all Green functions of the theory by an infinite tower of integral equations, and the corresponding Bethe-Salpeter equations that define the bound states of the theory. To reduce the infinite tower to a tractable form, the equations have to be truncated. In this thesis the so-called rainbow ladder' truncation was used that reduces the quark-gluon vertex to the bare vertex and replaces the gluon by an effective modeled one so that the only Green function that has to be solved, is the quark propagator. This truncation preserves the important axial Ward-Takahashi-identity and the Gell-Mann-Oakes-Renner relation. For the effective gluon the Maris-Tandy interaction was used, modeled to reproduce the pion mass and decay constant. Starting from this well-established truncation, the four-body tetraquark Bethe-Salpeter equation was constructed. To solve the tetraquark Bethe-Salpeter equation, a fully covariant basis for the tetraquark amplitude is necessary. Additionally, the basis has to reflect the quantum numbers of the tetraquark and has to fulfill the Pauli principle. The construction of such a basis was performed for all parts of the amplitude: The Dirac-tensor structure, the phase space, the colour and the flavour tensor structure. Upon solving the tetraquark bound state equation, dynamical pion poles in the tetraquark amplitude phase space appeared, reflecting the actual physics that determines the tetraquark: The tetraquark is dominated by two-body correlations which manifest themselves as poles in the phase space. It is especially noteworthy that these two-body correlations in form of poles

  20. The Statistical Modeling of the Trends Concerning the Romanian Population

    Directory of Open Access Journals (Sweden)

    Gabriela OPAIT

    2014-11-01

    Full Text Available This paper reflects the statistical modeling concerning the resident population in Romania, respectively the total of the romanian population, through by means of the „Least Squares Method”. Any country it develops by increasing of the population, respectively of the workforce, which is a factor of influence for the growth of the Gross Domestic Product (G.D.P.. The „Least Squares Method” represents a statistical technique for to determine the trend line of the best fit concerning a model.

  1. Bovine spongiform encephalopathy (BSE)--infectious, contagious, zoonotic or production disease?

    Science.gov (United States)

    Doherr, Marcus G

    2003-01-01

    In 1986, a new progressive neurological condition similar to scrapie of sheep and goats was recognised in cattle in the United Kingdom (UK), and was named bovine spongiform encephalopathy (BSE). There is an ongoing discussion whether BSE should be classified as infectious, contagious, or zoonotic, and if it fits the definition of a production disease. The objective of this work is to briefly describe the main characteristics of transmissible spongiform encephalopathies (TSE), to review the epidemiology of BSE, and to address the question of how to classify BSE. TSEs are characterised as chronic wasting diseases with spongiform vacuolation and the accumulation of infectious prion protein (PrP(Sc)) in the central nervous system. TSE infectivity is very difficult to inactivate. Cattle BSE most likely originated from sheep scrapie, although this will remain to be an issue for debate. The disease can be transmitted from cattle to a range of species, and has resulted in smaller TSE epidemics in domestic cats, zoo cats and zoo ruminants, and in humans. Transmission in the field occurred through feed containing ruminant-derived protein, and measures to prevent the recycling of infectivity have proven effective to reduce the number of new infections. Mandatory reporting of clinical suspects combined with targeted screening of risk populations is needed to assess the BSE status of a country. Infection studies and the transmissibility to other species classify BSE as infectious and zoonotic. Absence of excretion of the agent, and therefore of horizontal transmission, categorise BSE as non-contagious. However, BSE is a multifactorial infectious disease that is dependent on management factors (mainly feeding), and therefore fits into the broader definition of production diseases.

  2. Bovine Spongiform Encephalopathy (BSE – Infectious, Contagious, Zoonotic or Production Disease?

    Directory of Open Access Journals (Sweden)

    Doherr Marcus G

    2003-03-01

    Full Text Available In 1986, a new progressive neurological condition similar to scrapie of sheep and goats was recognised in cattle in the United Kingdom (UK, and was named bovine spongiform encephalopathy (BSE. There is an ongoing discussion whether BSE should be classified as infectious, contagious, or zoonotic, and if it fits the definition of a production disease. The objective of this work is to briefly describe the main characteristics of transmissible spongiform encephalopathies (TSE, to review the epidemiology of BSE, and to address the question of how to classify BSE. TSEs are characterised as chronic wasting diseases with spongiform vacuolation and the accumulation of infectious prion protein (PrPSc in the central nervous system. TSE infectivity is very difficult to inactivate. Cattle BSE most likely originated from sheep scrapie, although this will remain to be an issue for debate. The disease can be transmitted from cattle to a range of species, and has resulted in smaller TSE epidemics in domestic cats, zoo cats and zoo ruminants, and in humans. Transmission in the field occurred through feed containing ruminant-derived protein, and measures to prevent the recycling of infectivity have proven effective to reduce the number of new infections. Mandatory reporting of clinical suspects combined with targeted screening of risk populations is needed to assess the BSE status of a country. Infection studies and the transmissibility to other species classify BSE as infectious and zoonotic. Absence of excretion of the agent, and therefor of horizontal transmission, categorise BSE as non-contagious. However, BSE is a multifactorial infectious disease that is dependent on management factors (mainly feeding, and therefore fits into the broader definition of production diseases.

  3. Geographical BSE risk assessment and its impact on disease detection and dissemination.

    Science.gov (United States)

    Salman, Mo; Silano, Vittorio; Heim, Dagmar; Kreysa, Joachim

    2012-08-01

    Bovine Spongiform Encephalopathy (BSE) rapidly evolved into an issue of major public concern particularly when, in 1996, evidence was provided that this disease had crossed the species barrier and infected humans in the UK with what has become known as "variant Creutzfeldt Jakob Disease" (vCJD). The aim of this paper is to describe the European Geographical BSE risk assessment (GBR) that was successfully used for assessing the qualitative likelihood that BSE could be present in a country where it was not yet officially recognized. It also discusses how this can lead to risk-based and therefore preventive management of BSE at national and international levels. The basic assumption of the GBR method is that the BSE agent is initially introduced into a country's domestic cattle production system through the importation of contaminated feedstuffs or live cattle. This is referred to as an "external challenge". The ability of the system to cope with such a challenge is, in turn, referred to as its "stability": a stable system will not allow the BSE agent to propagate and amplify following its introduction, while an unstable system will. The BSE-status of a country assessed by this system was used by the European Commission as the basis for trade legislation rules for cattle and their products. The GBR was an invaluable tool in evaluating the potential global spread of BSE as it demonstrated how a disease could be transferred through international trade. This was shown to be a critical factor to address in reducing the spread and amplification of BSE throughout the world. Furthermore, GBR resulted in the implementation of additional measures and management activities both to improve surveillance and to prevent transmission within the cattle population.

  4. Bovine Spongiform Encephalopathy (BSE – Infectious, Contagious, Zoonotic or Production Disease?

    Directory of Open Access Journals (Sweden)

    Doherr Marcus G

    2003-03-01

    Full Text Available In 1986, a new progressive neurological condition similar to scrapie of sheep and goats was recognised in cattle in the United Kingdom (UK, and was named bovine spongiform encephalopathy (BSE. There is an ongoing discussion whether BSE should be classified as infectious, contagious, or zoonotic, and if it fits the definition of a production disease. The objective of this work is to briefly describe the main characteristics of transmissible spongiform encephalopathies (TSE, to review the epidemiology of BSE, and to address the question of how to classify BSE. TSEs are characterised as chronic wasting diseases with spongiform vacuolation and the accumulation of infectious prion protein (PrPSc in the central nervous system. TSE infectivity is very difficult to inactivate. Cattle BSE most likely originated from sheep scrapie, although this will remain to be an issue for debate. The disease can be transmitted from cattle to a range of species, and has resulted in smaller TSE epidemics in domestic cats, zoo cats and zoo ruminants, and in humans. Transmission in the field occurred through feed containing ruminant-derived protein, and measures to prevent the recycling of infectivity have proven effective to reduce the number of new infections. Mandatory reporting of clinical suspects combined with targeted screening of risk populations is needed to assess the BSE status of a country. Infection studies and the transmissibility to other species classify BSE as infectious and zoonotic. Absence of excretion of the agent, and therefor of horizontal transmission, categorise BSE as non-contagious. However, BSE is a multifactorial infectious disease that is dependent on management factors (mainly feeding, and therefore fits into the broader definition of production diseases.

  5. The Liquidity of the Bucharest Stock Exchange (BSE during the Financial Crisis

    Directory of Open Access Journals (Sweden)

    Ion STANCU

    2010-05-01

    Full Text Available The paper presents the evolution of BSE during the financial crisis in 2008. The investors’ preferences for blue chips shares remained unchanged, there were traded the same shares in almost the same volumes. The shares’ prices are highly positive correlated, the reduce liquidity of BSE determine the investors’ preferences for liquid shares. The crisis determined a decrease in the transactions volume and value and in the number of shares traded, with major impact over the shares’ prices, possible due to emotion reaction of investors. BSE is still attractive, having low prices and high future possibility of increasing.

  6. Apply a hydrological model to estimate local temperature trends

    Science.gov (United States)

    Igarashi, Masao; Shinozawa, Tatsuya

    2014-03-01

    Continuous times series {f(x)} such as a depth of water is written f(x) = T(x)+P(x)+S(x)+C(x) in hydrological science where T(x),P(x),S(x) and C(x) are called the trend, periodic, stochastic and catastrophic components respectively. We simplify this model and apply it to the local temperature data such as given E. Halley (1693), the UK (1853-2010), Germany (1880-2010), Japan (1876-2010). We also apply the model to CO2 data. The model coefficients are evaluated by a symbolic computation by using a standard personal computer. The accuracy of obtained nonlinear curve is evaluated by the arithmetic mean of relative errors between the data and estimations. E. Halley estimated the temperature of Gresham College from 11/1692 to 11/1693. The simplified model shows that the temperature at the time rather cold compared with the recent of London. The UK and Germany data sets show that the maximum and minimum temperatures increased slowly from the 1890s to 1940s, increased rapidly from the 1940s to 1980s and have been decreasing since the 1980s with the exception of a few local stations. The trend of Japan is similar to these results.

  7. Stratospheric age-of-air trends: Reanalysis v. climate models

    Science.gov (United States)

    Monge-Sanz, Beatriz; Dee, Dick; Hersbach, Hans; Simmons, Adrian; Parodi, Jose A.; Haenel, Florian; Stiller, Gabriele; Chipperfield, Martyn; Feng, Wuhu

    2017-04-01

    Knowing how the Brewer-Dobson circulation (BDC) has evolved in the recent past and will continue to evolve is crucial for atmospheric composition in the UTLS and stratosphere, as well as for feedbacks with climate. Most climate models have predicted an intensification of the stratospheric circulation with the increase in greenhouse gases concentrations, which translates into younger age-of-air (AoA) values modelled in the stratosphere. Nevertheless, balloon and satellite observations do not agree with the widespread modelled trend towards younger age-of-air for the recent past (Engel et al., 2009; Stiller et al., 2012; Haenel et al. 2015). Furthermore, a few recent studies with chemistry transport models (CTMs) driven by ERA-Interim reanalysis (Dee et al., 2011) have also shown agreement with the observed trends and not with those from climate models (e.g. Monge-Sanz et al., 2012; Diallo et al., 2012; Ploeger et al., 2015). To increase our confidence in climate-chemistry projections, the causes for the apparent disagreement in trends of age-of-air between observations and most climate models need to be identified. In this study we have carried out simulations with a CTM to assess the stratospheric circulation with the ERA-Interim dataset produced by the European Centre for Medium-Range Weather Forecasts (ECMWF), as well as with data produced from an equivalent climate system. AoA trends from our model results with ERA-Interim fields are in good agreement with the recent age-of-air studies based on observations and differ from the results we obtain with the corresponding climate data. We will show that biases in the mean AoA values are also different for these datasets compared to observations. In addition we have used recent experimental datasets from the ECMWF system to identify potential causes for the differences in AoA distribution and trends. The validation of our model results has been performed against the new revised AoA dataset based on MIPAS SF6

  8. Temporal and spatial patterns of the clinical surveillance of BSE in France, analysed from January 1991 to May 2002 through a vigilance index.

    Science.gov (United States)

    Cuenot, Marie; Calavas, Didier; Abrial, David; Gasqui, Patrick; Cazeau, Géraldine; Ducrot, Christian

    2003-01-01

    Between 1991 and mid 2000, the surveillance of Bovine Spongiform Encephalopathy (BSE) in France was based solely on clinical surveillance through a Mandatory Reporting System. Since 2000, the implementation of active surveillance programmes using rapid tests, as a complementary tool targeted at dead and slaughtered cattle has shown that part of the BSE cases were not detected with the clinical surveillance. In order to obtain a better knowledge of the strength of the clinical surveillance, we analysed a vigilance index defined as the ratio of negative clinical suspicions to the cattle population in the region and period of interest. The temporal analysis of the vigilance index showed that it did not vary much between 1991 and 1999, increased sharply since 2000, and then decreased partly in 2001. The geographical analysis of the variations of the vigilance index was performed at the department level by comparing the observed number of negative clinical suspicions per department to the expected number, computed on the basis of the national average index and standardised on the production type of the cattle - dairy versus beef suckling cattle. As assumed, the data followed a Poisson distribution. We observed a high geographical variation of the vigilance index: ten departments out of 91 presented a significantly higher vigilance index than the national one, and four a significantly lower vigilance index. The vigilance index showed that the clinical surveillance was heterogeneous during the past twelve years, both in time and geographic location, in a range of one to ten. So the apparent trend in the BSE epidemic during this period as well as the differences in the spatial incidence of BSE have to be analysed with caution.

  9. Pruritus is a common feature in sheep infected with the BSE agent

    Directory of Open Access Journals (Sweden)

    Jeffrey Martin

    2008-04-01

    Full Text Available Abstract Background The variability in the clinical or pathological presentation of transmissible spongiform encephalopathies (TSEs in sheep, such as scrapie and bovine spongiform encephalopathy (BSE, has been attributed to prion protein genotype, strain, breed, clinical duration, dose, route and type of inoculum and the age at infection. The study aimed to describe the clinical signs in sheep infected with the BSE agent throughout its clinical course to determine whether the clinical signs were as variable as described for classical scrapie in sheep. The clinical signs were compared to BSE-negative sheep to assess if disease-specific clinical markers exist. Results Forty-seven (34% of 139 sheep, which comprised 123 challenged sheep and 16 undosed controls, were positive for BSE. Affected sheep belonged to five different breeds and three different genotypes (ARQ/ARQ, VRQ/VRQ and AHQ/AHQ. None of the controls or BSE exposed sheep with ARR alleles were positive. Pruritus was present in 41 (87% BSE positive sheep; the remaining six were judged to be pre-clinically infected. Testing of the response to scratching along the dorsum of a sheep proved to be a good indicator of clinical disease with a test sensitivity of 85% and specificity of 98% and usually coincided with weight loss. Clinical signs that were displayed significantly earlier in BSE positive cases compared to negative cases were behavioural changes, pruritic behaviour, a positive scratch test, alopecia, skin lesions, teeth grinding, tremor, ataxia, loss of weight and loss of body condition. The frequency and severity of each specific clinical sign usually increased with the progression of disease over a period of 16–20 weeks. Conclusion Our results suggest that BSE in sheep presents with relatively uniform clinical signs, with pruritus of increased severity and abnormalities in behaviour or movement as the disease progressed. Based on the studied sheep, these clinical features appear to

  10. Pruritus is a common feature in sheep infected with the BSE agent.

    Science.gov (United States)

    Konold, Timm; Bone, Gemma; Vidal-Diez, Alberto; Tortosa, Raul; Davis, Andrew; Dexter, Glenda; Hill, Peter; Jeffrey, Martin; Simmons, Marion M; Chaplin, Melanie J; Bellworthy, Susan J; Berthelin-Baker, Christine

    2008-04-29

    The variability in the clinical or pathological presentation of transmissible spongiform encephalopathies (TSEs) in sheep, such as scrapie and bovine spongiform encephalopathy (BSE), has been attributed to prion protein genotype, strain, breed, clinical duration, dose, route and type of inoculum and the age at infection. The study aimed to describe the clinical signs in sheep infected with the BSE agent throughout its clinical course to determine whether the clinical signs were as variable as described for classical scrapie in sheep. The clinical signs were compared to BSE-negative sheep to assess if disease-specific clinical markers exist. Forty-seven (34%) of 139 sheep, which comprised 123 challenged sheep and 16 undosed controls, were positive for BSE. Affected sheep belonged to five different breeds and three different genotypes (ARQ/ARQ, VRQ/VRQ and AHQ/AHQ). None of the controls or BSE exposed sheep with ARR alleles were positive. Pruritus was present in 41 (87%) BSE positive sheep; the remaining six were judged to be pre-clinically infected. Testing of the response to scratching along the dorsum of a sheep proved to be a good indicator of clinical disease with a test sensitivity of 85% and specificity of 98% and usually coincided with weight loss. Clinical signs that were displayed significantly earlier in BSE positive cases compared to negative cases were behavioural changes, pruritic behaviour, a positive scratch test, alopecia, skin lesions, teeth grinding, tremor, ataxia, loss of weight and loss of body condition. The frequency and severity of each specific clinical sign usually increased with the progression of disease over a period of 16-20 weeks. Our results suggest that BSE in sheep presents with relatively uniform clinical signs, with pruritus of increased severity and abnormalities in behaviour or movement as the disease progressed. Based on the studied sheep, these clinical features appear to be independent of breed, affected genotype, dose, route

  11. Studies of embryo transfer from cattle clinically affected by bovine spongiform encephalopathy (BSE).

    Science.gov (United States)

    Wrathall, A E; Brown, K F D; Sayers, A R; Wells, G A H; Simmons, M M; Farrelly, S S J; Bellerby, P; Squirrell, J; Spencer, Y I; Wells, M; Stack, M J; Bastiman, B; Pullar, D; Scatcherd, J; Heasman, L; Parker, J; Hannam, D A R; Helliwell, D W; Chree, A; Fraser, H

    2002-03-23

    Semen from 13 bulls, eight with clinical bovine spongiform encephalopathy (BSE), was used to artificially inseminate (AI) 167 cows with clinical BSE, and their resultant embryos were collected non-surgically seven days after AI. The viable and non-viable embryos with intact zonae pellucidae were washed 10 times (as recommended by the International Embryo Transfer Society) then frozen. Later, 587 of the viable embryos were transferred singly into 347 recipient heifers imported from New Zealand, and 266 live offspring were born of which 54.1 per cent had a BSE-positive sire and a BSE-positive dam. The recipients were monitored for clinical signs of BSE for seven years after the transfer, and the offspring were monitored for seven years after birth. Twenty-seven of the recipients and 20 offspring died while being monitored but none showed signs of BSE. Their brains, and the brains of the recipients and offspring killed after seven years, were examined for BSE by histopathology, PrP immunohistochemistry, and by electron microscopy for scrapie-associated fibrils. They were all negative. In addition, 1020 non-viable embryos were sonicated and injected intracerebrally into susceptible mice (20 embryos per mouse) which were monitored for up to 700 days, after which their brains were examined for spongiform lesions. They were all negative. It is concluded that embryos are unlikely to carry BSE infectivity even if they have been collected at the end-stage of the disease, when the risk of maternal transmission is believed to be highest.

  12. Could measuring of perceived risk among general practitioners have helped anticipate the French BSE crisis?

    Science.gov (United States)

    Setbon, Michel; Fischler, Claude; Lukasiewicz, Esther; Raude, Jocelyn; Flahault, Antoine

    2004-01-01

    In October of 2000, a second BSE crisis caught French public authorities unprepared and caused a collapse in beef consumption as well as considerable political turmoil. Data collected between May and July, 2000, among a group of general practitioners (GPs), while national consumption of beef was back to pre-BSE levels, paradoxically showed high latent risk perception, suggesting a new crisis was possible or likely.

  13. Recent trends in the modeling of cellulose hydrolysis

    Directory of Open Access Journals (Sweden)

    R. Sousa Jr.

    2011-12-01

    Full Text Available This work reviews recent trends in the modeling of cellulose hydrolysis, within the perspective of application of kinetic models in a bioreactor engineering framework, including scale-up, design and process optimization. From this point of view, despite the phenomenological insight that mechanistic models can provide, the expectation that more detailed approaches could be a basis for extrapolations to different substrates and/or enzymatic pools is still not fulfilled. The complexity of the lignocellulosic matrix, the different mechanisms of catalytic action, the role of mass transfer limitations and the deviations from ideal mixing are important difficulties for the modeler, which will continue to impose more conservative approaches for scale-up. Nevertheless, the search for more robust models is a very important task, provided that the engineer is aware of their limitations. Data-driven, non-mechanistic models such as artificial neural networks, perhaps in combination with other approaches in the so-called hybrid models, is also a promising alternative.

  14. A single step multiplex immunofluorometric assay for differential diagnosis of BSE and scrapie.

    Science.gov (United States)

    Tang, Yue; Thorne, Jemma; Whatling, Kirsty; Jacobs, Jorg G; Langeveld, Jan; Sauer, Maurice J

    2010-04-30

    Although there is no evidence that the European sheep population has been infected with bovine spongiform encephalopathy (BSE), distinguishing this from scrapie is paramount, given the association between BSE exposure and the human transmissible spongiform encephalopathy (TSE), variant Creutzfeldt-Jakob disease. The capability to differentially diagnose TSEs in sheep is thus essential in order to safeguard the food chain and human health. Biochemical methods for differentiating BSE and scrapie are largely reliant on assessment by Western blot (WB) analysis of the abnormal disease associated prion protein PrP(D) following partial proteolytic digestion. WB banding patterns obtained using a panel of antibodies enable different strain specific conformations of PrP(D) to be distinguished. This approach provides a robust confirmatory test but one which is not appropriate for high throughput screening. A simple, one step, bead array flow cytometry based multiplex immunofluorometric assay has been developed which is suitable for simultaneous screening and confirmation. Using a combination of antibodies directed towards three PrP epitopes enabled differential diagnosis of scrapie and BSE. Proof of principle studies indicated a high predictive value (100%) when applied to brain samples from control animals, BSE infected cattle and sheep naturally infected with scrapie or experimentally infected with BSE.

  15. The Perils of Committee Governance: Intergovernmental Bargaining during the BSE Scandal in the European Union

    Directory of Open Access Journals (Sweden)

    Karolina Zurek

    2006-05-01

    Full Text Available This paper contributes to the ongoing debate between principal-agent theory and the concept of deliberative supranationalism regarding the functioning of the EU committee system by analysing regulatory policy-making in the BSE case. The BSE crisis can be seen as a critical instance for committee governance. This paper argues that the EUs mismanagement of the BSE crisis was mainly due to the prevalence of member states parochial interests, which clearly supports a rationalist perception of the EU committee system. Whereas the committee system might lead to deliberative problem-solving in more favourable circumstances, the distributive consequences of BSE regulations were asymmetric and too large to permit individual concessions. Consequently, the EU committee system institutions were too weak to prevent reversion to intergovernmental politics. The UK initially downplayed the problem in order to protect its beef industry against a likely ban in the Single Market. After the BSE health risk became evident in 1996, the other member states reacted by banning British beef imports. Throughout these episodes, scientific evidence indicated that neither the British nor the other member states strategies were sustainable. Only when BSE became Europeanised in 2000 were the member states able to adopt common policies to fight the disease. Whether the new European Food Safety Agency will be able to prevent such crises in the future is an open question, but is doubtful in light of its institutional weakness.

  16. Cointegration between trends and their estimators in state space models and CVAR models

    DEFF Research Database (Denmark)

    Johansen, Søren; Tabor, Morten Nyboe

    In a linear state space model, y_{t+1}=BT_{t}+eps_{t+1}, we investigate if the unobserved trend, T_{t}, cointegrates with the extracted trend E_{t}T_{t}, and with the estimated trend E^_{t}T_{t}, in the sense that the spreads T_{t}-E_{t}T_{t} and E_{t}T_{t}-E^_{t}T_{t} are stationary. We find...... that this result holds for BT_{t}-BE_{t}T_{t} and BE_{t}T_{t}-B^E^_{t}T_{t}. For the trends T_{t} and E^_{t}T_{t}, however, this type cointegration depends on the identification of B and T_{t}. The same results are found, if the observations, y_{t}, from the state space model are analysed using a cointegrated...... vector autoregressive model, where the trend is defined as the common trend. Finally we investigate cointegration between trends and their estimators based on the two models, and find the same results. We illustrate with two examples and confirm the results by a small simulation study....

  17. The Development of a Cultural-Based Educational Program to Enhance Breast Self-Examination (BSE Self-Efficacy

    Directory of Open Access Journals (Sweden)

    Juanita Juanita

    2012-08-01

    Full Text Available Purpose: To develop the educational program which is appropriate with Islamic culture in order to enhance BSE self-efficacy of nursing students and thus promote BSE practice. Method: This study is a development research study which is consisting of three phases including: 1 reviewing several existing BSE educational programs; 2 program design based on SCT and Islamic culture; and 3 program validation by three experts. Result: Based on previous studies, the most appropriate theory to enhance self-efficacy was Social Cognitive Theory (SCT because this theory provides several strategies to increase the self-efficacy. Further, the program that used Islamic culture was more appropriate to increase BSE practice among Muslim women. As a result, the newly developed program was developed used SCT and Islamic culture. This program was comprised of four sessions including: 1 exploring Islamic mandate on prevention and individual responsibility in health promotion, and culture-related beliefs toward BSE, 2 health education by conducting lecturing session and watching a video about BSE procedures, 3 BSE training activities including BSE demonstration and return demonstration, 4 follow-up by conducting a meeting. Conclusion: The cultural-based educational program for enhancing BSE self-efficacy and promoting BSE is a program using multifaceted methods. It designed based on a review of the literature from previous studies and were supported by research findings on experimental studies in other population. Keywords: Cultural, Educational program development, Breast self-examination, Self-efficacy.

  18. Recent trends in social systems quantitative theories and quantitative models

    CERN Document Server

    Hošková-Mayerová, Šárka; Soitu, Daniela-Tatiana; Kacprzyk, Janusz

    2017-01-01

    The papers collected in this volume focus on new perspectives on individuals, society, and science, specifically in the field of socio-economic systems. The book is the result of a scientific collaboration among experts from “Alexandru Ioan Cuza” University of Iaşi (Romania), “G. d’Annunzio” University of Chieti-Pescara (Italy), "University of Defence" of Brno (Czech Republic), and "Pablo de Olavide" University of Sevilla (Spain). The heterogeneity of the contributions presented in this volume reflects the variety and complexity of social phenomena. The book is divided in four Sections as follows. The first Section deals with recent trends in social decisions. Specifically, it aims to understand which are the driving forces of social decisions. The second Section focuses on the social and public sphere. Indeed, it is oriented on recent developments in social systems and control. Trends in quantitative theories and models are described in Section 3, where many new formal, mathematical-statistical to...

  19. The Hierarchical Trend Model for property valuation and local price indices

    NARCIS (Netherlands)

    M.K. Francke; G.A. Vos

    2002-01-01

    This paper presents a hierarchical trend model (HTM) for selling prices of houses, addressing three main problems: the spatial and temporal dependence of selling prices and the dependency of price index changes on housing quality. In this model the general price trend, cluster-level price trends, an

  20. Evaluation of two sets of immunohistochemical and Western blot confirmatory methods in the detection of typical and atypical BSE cases

    Directory of Open Access Journals (Sweden)

    Greenlee Justin J

    2011-09-01

    Full Text Available Abstract Background Three distinct forms of bovine spongiform encephalopathy (BSE, defined as classical (C-, low (L- or high (H- type, have been detected through ongoing active and passive surveillance systems for the disease. The aim of the present study was to compare the ability of two sets of immunohistochemical (IHC and Western blot (WB BSE confirmatory protocols to detect C- and atypical (L- and H-type BSE forms. Obex samples from cases of United States and Italian C-type BSE, a U.S. H-type and an Italian L-type BSE case were tested in parallel using the two IHC sets and WB methods. Results The two IHC techniques proved equivalent in identifying and differentiating between C-type, L-type and H-type BSE. The IHC protocols appeared consistent in the identification of PrPSc distribution and deposition patterns in relation to the BSE type examined. Both IHC methods evidenced three distinct PrPSc phenotypes for each type of BSE: prevailing granular and linear tracts pattern in the C-type; intraglial and intraneuronal deposits in the H-type; plaques in the L-type. Also, the two techniques gave comparable results for PrPSc staining intensity on the C- and L-type BSE samples, whereas a higher amount of intraglial and intraneuronal PrPSc deposition on the H-type BSE case was revealed by the method based on a stronger demasking step. Both WB methods were consistent in identifying classical and atypical BSE forms and in differentiating the specific PrPSc molecular weight and glycoform ratios of each form. Conclusions The study showed that the IHC and WB BSE confirmatory methods were equally able to recognize C-, L- and H-type BSE forms and to discriminate between their different immunohistochemical and molecular phenotypes. Of note is that for the first time one of the two sets of BSE confirmatory protocols proved effective in identifying the L-type BSE form. This finding helps to validate the suitability of the BSE confirmatory tests for BSE

  1. Stochastic modeling of Lake Van water level time series with jumps and multiple trends

    Directory of Open Access Journals (Sweden)

    H. Aksoy

    2013-06-01

    Full Text Available In the 1990s, water level in the closed-basin Lake Van located in the Eastern Anatolia, Turkey, has risen up about 2 m. Analysis of the hydrometeorological data shows that change in the water level is related to the water budget of the lake. In this study, stochastic models are proposed for simulating monthly water level data. Two models considering mono- and multiple-trend time series are developed. The models are derived after removal of trend and periodicity in the dataset. Trend observed in the lake water level time series is fitted by mono- and multiple-trend lines. In the so-called mono-trend model, the time series is treated as a whole under the hypothesis that the lake water level has an increasing trend. In the second model (so-called multiple-trend, the time series is divided into a number of segments to each a linear trend can be fitted separately. Application on the lake water level data shows that four segments, each fitted with a trend line, are meaningful. Both the mono- and multiple-trend models are used for simulation of synthetic lake water level time series under the hypothesis that the observed mono- and multiple-trend structure of the lake water level persist during the simulation period. The multiple-trend model is found better for planning the future infrastructural projects in surrounding areas of the lake as it generates higher maxima for the simulated lake water level.

  2. Cooperative Trends in a Modified Image Scoring Model

    Institute of Scientific and Technical Information of China (English)

    ANDREASEN Jonathan; 欧阳颀

    2002-01-01

    The evolution of modern cooperative trends now seen in society have not yet been easily explained. After extensive computational studies and theoretical analysis, Nowak and Sigmund proposed that cooperation was established largely due to the emergence of indirect reciprocity. Our previous studies show that a high information flow rate stimulates cooperation in a society. In this study we find that the decrease of cooperation cost will make a society more cooperative, and the inheritance of wealth will induce cooperation in the society even when the exchange rate is comparatively low. We also study the distribution of knowledge according to wealth. Wefind that, for this model, cooperation is slightly less likely to occur if the exchange rate is low.

  3. Identification of the characteristics and risk factors of the BSE epidemic in the Netherlands.

    Science.gov (United States)

    Heres, Lourens; Elbers, Armin R W; van Zijderveld, Fred G

    2007-10-01

    It is generally accepted that the bovine spongiform encephalopathy (BSE) epidemic is transmitted by feed contamination with meat and bone meal (MBM). Whether in some cases substances other than MBM have caused the spread of this disease cannot be excluded at present. Detailed knowledge about country-specific transmission routes and relevant risk factors is important to perform accurate risk analyses and to control BSE. In the present study all possible information of Dutch BSE cases was collected. The general epidemiological data were first used for a comprehensive descriptive analysis of the Dutch BSE epidemic. A case-control study was performed to identify the risk factors associated with the occurrence of BSE cases in the Netherlands. Sixty-eight of the 76 BSE cases enrolled in the case-control study. With an oral questionnaire information was collected about cow and farm management. The same questionnaire was used in interviews at 128 randomly selected control farms. Detailed analysis of the case anamneses showed that all affected cows could have been exposed to MBM from pig or poultry feed as a result of cross-contamination. In the case-control study, only feed producer appeared to be a relevant risk factor. Differences in log odds between feed producers were related to the moment of separation of production lines and to the origin of the MBM. The results suggest that there were meaningful differences in the level of infectivity in MBM from different origins at the time that cross-contamination was still possible. No other risk factors, either farm or cow related, were significantly associated with the occurrence of BSE.

  4. Improvement of goat TSE discriminative diagnosis and susceptibility based assessment of BSE infectivity in goat milk and meat

    OpenAIRE

    2012-01-01

    In light of the known ability of the BSE agent to cross the animal/human species barrier, the evidence establishing the presence of BSE in goat is especially alarming, as it represents a potential risk of food-born contamination to human consumers of goat milk and meat products. The main objective has been to determine the tissue distribution of BSE after oral exposure of goats while simultaneously generating in dispensable data on genetic susceptibility in the most commonly used production b...

  5. Experimental transmission of two young and one suspended bovine spongiform encephalopathy (BSE) cases to bovinized transgenic mice.

    Science.gov (United States)

    Yokoyama, Takashi; Masujin, Kentaro; Yamakawa, Yoshio; Sata, Tetsutaro; Murayama, Yuichi; Shu, Yujing; Okada, Hiroyuki; Mohri, Shirou; Shinagawa, Morikazu

    2007-09-01

    Bovine spongiform encephalopathy (BSE) is caused by a prion that primarily consists of an abnormal isoform of the prion protein (PrP(Sc)). Since PrP(Sc) is partially resistant to proteolytic digestion, the routine diagnosis of BSE is based on the immunological detection of the proteinase K (PK)-resistant moiety of PrP(Sc) (PrP(core)). However, transmission studies are indispensable in order to demonstrate prion infectivity and to analyze prion characteristics. Transmission experiments were accordingly performed on 2 young BSE cases (BSE/JP8, BSE/JP9) and 1 suspected BSE case (Suspended-1) that were detected by the BSE screening program in Japan. In this study, we attempted to transmit the prion from these 3 animals by using transgenic mice overexpressing bovine PrP (TgBoPrP). In spite of the use of BSE-sensitive transgenic mice, none of the mice developed neurological signs nor accumulated PrP(Sc) in their brains for more than 600 days post-inoculation, even with subsequent blind passages. The results of a dilution experiment using the classical BSE prion indicated that prion infectivity in these 3 cattle was below the detection limit of 10(3.0) LD(50)/g.

  6. Rapid and discriminatory diagnosis of scrapie and BSE in retro-pharyngeal lymph nodes of sheep

    Directory of Open Access Journals (Sweden)

    van Zijderveld Fred G

    2006-06-01

    Full Text Available Abstract Background Diagnosis based on prion detection in lymph nodes of sheep and goats can improve active surveillance for scrapie and, if it were circulating, for bovine spongiform encephalopathy (BSE. With sizes that allow repetitive testing and a location that is easily accessible at slaughter, retropharyngeal lymph nodes (RLN are considered suitable organs for testing. Western blotting (WB of brain homogenates is, in principle, a technique well suited to both detect and discriminate between scrapie and BSE. In this report, WB is developed for rapid diagnosis in RLN and to study biochemical characteristics of PrPres. Results Optimal PrPres detection in RLN by WB was achieved by proper tissue processing, antibody choice and inclusion of a step for PrPresconcentration. The analyses were performed on three different sheep sources. Firstly, in a study with preclinical scrapie cases, WB of RLN from infected sheep of VRQ/VRQ genotype – VRQ represents, respectively, polymorphic PrP amino acids 136, 154, and 171 – allowed a diagnosis 14 mo earlier compared to WB of brain stem. Secondly, samples collected from sheep with confirmed scrapie in the course of passive and active surveillance programmes in the period 2002–2003 yielded positive results depending on genotype: all sheep with genotypes ARH/VRQ, VRQ/VRQ, and ARQ/VRQ scored positive for PrPres, but ARQ/ARQ and ARR/VRQ were not all positive. Thirdly, in an experimental BSE study, detection of PrPres in all 11 ARQ/ARQ sheep, including 7 preclinical cases, was possible. In all instances, WB and IHC were almost as sensitive. Moreover, BSE infection could be discriminated from scrapie infection by faster electrophoretic migration of the PrPres bands. Using dual antibody staining with selected monoclonal antibodies like 12B2 and L42, these differences in migration could be employed for an unequivocal differentiation between BSE and scrapie. With respect to glycosylation of PrPres, BSE cases

  7. Assessing the consistency between short-term global temperature trends in observations and climate model projections

    CERN Document Server

    Michaels, Patrick J; Christy, John R; Herman, Chad S; Liljegren, Lucia M; Annan, James D

    2013-01-01

    Assessing the consistency between short-term global temperature trends in observations and climate model projections is a challenging problem. While climate models capture many processes governing short-term climate fluctuations, they are not expected to simulate the specific timing of these somewhat random phenomena - the occurrence of which may impact the realized trend. Therefore, to assess model performance, we develop distributions of projected temperature trends from a collection of climate models running the IPCC A1B emissions scenario. We evaluate where observed trends of length 5 to 15 years fall within the distribution of model trends of the same length. We find that current trends lie near the lower limits of the model distributions, with cumulative probability-of-occurrence values typically between 5 percent and 20 percent, and probabilities below 5 percent not uncommon. Our results indicate cause for concern regarding the consistency between climate model projections and observed climate behavior...

  8. Alternative BSE risk assessment methodology for beef and beef offal imported into Japan.

    Science.gov (United States)

    Yoshikawa, Yasuhiro; Horiuchi, Motohiro; Ishiguro, Naotaka; Kadohira, Mutsuyo; Kai, Satoshi; Mizusawa, Hidehiro; Nagata, Chisato; Onodera, Takashi; Sata, Tetsutaro; Tsutsui, Toshiyuki; Yamada, Masahito; Yamamoto, Shigeki

    2012-08-01

    The Food Safety Commission (FSC) of Japan, established in July 2003, has its own initiative to conduct risk assessments on food stuffs known as "self-tasking assessment". Within this framework, the FSC decided to conduct a risk assessment of beef and beef offal imported into Japan from countries with no previous BSE reports; thus, a methodology was formed to suit to this purpose. This methodology was partly based on the previous assessments of Japanese domestic beef and beef imported from U.S.A./Canada, but some modifications were made. Other organizations' assessment methods, such as those used for BSE status assessment in live cattle by the OIE and EFSA's GBR, were also consulted. In this review, the authors introduce this alternative methodology, which reflects (1) the risk of live cattle in the assessed country including temporal risks of BSE invasion and domestic propagation, with the assessment results verified by surveillance data, and (2) the risk of beef and beef offal consisting of cumulative BSE risk by types of slaughtering and meat production processes implemented and the status of mechanically recovered meat production. Other possible influencing factors such as atypical BSE cases were also reviewed. The key characteristic of the current assessment is a combination of the time-sequential risk level of live cattle and qualitative risk level of meat production at present in an assessed country.

  9. Lesion profiling at primary isolation in RIII mice is insufficient in distinguishing BSE from classical scrapie.

    Science.gov (United States)

    Beck, Katy E; Chaplin, Melanie; Stack, Michael; Sallis, Rosemary E; Simonini, Sarah; Lockey, Richard; Spiropoulos, John

    2010-03-01

    Primary isolation of bovine spongiform encephalopathy (BSE) in RIII mice generates a lesion profile believed to be reproducible and distinct from that produced by classical scrapie. This profile, which is characterized by peaks at gray matter areas 1, 4 and 7 (dorsal medulla, hypothalamus and septal nuclei), is used to diagnose BSE on primary isolation. The aim of this study was to investigate whether the BSE agent could be present in sheep diagnosed with classical scrapie, using lesion profiles in RIII mice as a discriminatory method. Sixty-two positive scrapie field cases were collected from individual farms between 1996 and 1999 and bioassayed in RIII mice. Fifty-five of these isolates transmitted successfully to at least one mouse. Of the 31 that produced adequate data to allow lesion profile analysis, 10 showed a consistent profile with peaks at brain areas 1, 4 and 7. All inocula for this subgroup were derived from sheep of genotype ARQ/ARQ. While the 1-4-7-scrapie profile exhibited similarities to BSE in RIII mice at primary isolation, it was distinguishable based on histopathology, immunohistochemistry and cluster analysis. We conclude that caution should be taken to distinguish this profile from BSE and that additional parameters should be considered to reach a final diagnosis.

  10. Causality and correlations between BSE and NYSE indexes: A Janus faced relationship

    Science.gov (United States)

    Neeraj; Panigrahi, Prasanta K.

    2017-09-01

    We study the multi-scale temporal correlations and causality connections between the New York Stock Exchange (NYSE) and Bombay Stock Exchange (BSE) monthly average closing price indexes for a period of 300 months, encompassing the time period of the liberalisation of the Indian economy and its gradual global exposure. In multi-scale analysis; clearly identifiable 1, 2 and 3 year non-stationary periodic modulations in NYSE and BSE have been observed, with NYSE commensurating changes in BSE at 3 years scale. Interestingly, at one year time scale, the two exchanges are phase locked only during the turbulent times, while at the scale of three year, in-phase nature is observed for a much longer time frame. The two year time period, having characteristics of both one and three year variations, acts as the transition regime. The normalised NYSE's stock value is found to Granger cause those of BSE, with a time lag of 9 months. Surprisingly, observed Granger causality of high frequency variations reveals BSE behaviour getting reflected in the NYSE index fluctuations, after a smaller time lag. This Janus faced relationship, shows that smaller stock exchanges may provide a natural setting for simulating market fluctuations of much bigger exchanges. This possibly arises due to the fact that high frequency fluctuations form an universal part of the financial time series, and are expected to exhibit similar characteristics in open market economies.

  11. Minimum Effective Dose of Cattle and Sheep BSE for Oral Sheep Infection.

    Directory of Open Access Journals (Sweden)

    Gillian McGovern

    Full Text Available The minimum dose required to cause infection of Romney and Suffolk sheep of the ARQ/ARQ or ARQ/ARR prion protein gene genotypes following oral inoculation with Romney or Suffolk a sheep Bovine spongiform encephalopathy (BSE-derived or cattle BSE-derived agent was investigated using doses ranging from 0.0005g to 5g. ARQ/ARQ sheep which were methionine (M / threonine (T heterozygous or T/T homozygous at codon 112 of the Prnp gene, dosed ARQ/ARR sheep and undosed controls did not show any evidence of infection. Within groups of susceptible sheep, the minimum effective oral dose of BSE was found to be 0.05g, with higher attack rates following inoculation with the 5g dose. Surprisingly, this study found no effect of dose on survival time suggesting a possible lack of homogeneity within the inoculum. All clinical BSE cases showed PrPd accumulation in brain; however, following cattle BSE inoculation, LRS involvement within Romney recipients was found to be significantly lower than within the Suffolk sheep inoculated group which is in agreement with previous reports.

  12. Stochastic modeling of Lake Van water level time series with jumps and multiple trends

    Directory of Open Access Journals (Sweden)

    H. Aksoy

    2013-02-01

    Full Text Available In 1990s, water level in the closed-basin Lake Van located in the Eastern Anatolia, Turkey has risen up about 2 m. Analysis of the hydrometeorological shows that change in the water level is related to the water budget of the lake. In this study, a stochastic model is generated using the measured monthly water level data of the lake. The model is derived after removal of trend and periodicity in the data set. Trend observed in the lake water level time series is fitted by mono- and multiple-trend lines. For the multiple-trend, the time series is first divided into homogeneous segments by means of SEGMENTER, segmentation software. Four segments are found meaningful practically each fitted with a trend line. Two models considering mono- and multiple-trend time series are developed. The multiple-trend model is found better for planning future development in surrounding areas of the lake.

  13. Factors affecting the accuracy of urine-based biomarkers of BSE

    Directory of Open Access Journals (Sweden)

    Ruddat Viola

    2011-02-01

    Full Text Available Abstract Background Transmissible spongiform encephalopathy diseases are untreatable, uniformly fatal degenerative syndromes of the central nervous system that can be transmitted both within as well as between species. The bovine spongiform encephalopathy (BSE epidemic and the emergence of a new human variant of Creutzfeldt-Jakob disease (vCJD, have profoundly influenced beef production processes as well as blood donation and surgical procedures. Simple, robust and cost effective diagnostic screening and surveillance tools are needed for both the preclinical and clinical stages of TSE disease in order to minimize both the economic costs and zoonotic risk of BSE and to further reduce the risk of secondary vCJD. Objective Urine is well suited as the matrix for an ante-mortem test for TSE diseases because it would permit non-invasive and repeated sampling. In this study urine samples collected from BSE infected and age matched control cattle were screened for the presence of individual proteins that exhibited disease specific changes in abundance in response to BSE infection that might form the basis of such an ante-mortem test. Results Two-dimensional differential gel electrophoresis (2D-DIGE was used to identify proteins exhibiting differential abundance in two sets of cattle. The known set consisted of BSE infected steers and age matched controls throughout the course of the disease. The blinded unknown set was composed of BSE infected and control samples of both genders, a wide range of ages and two different breeds. Multivariate analyses of individual protein abundance data generated classifiers comprised of the proteins best able to discriminate between the samples based on disease state, breed, age and gender. Conclusion Despite the presence of confounding factors, the disease specific changes in abundance exhibited by a panel of urine proteins permitted the creation of classifiers able to discriminate between control and infected cattle

  14. Sheep prions with molecular properties intermediate between classical scrapie, BSE and CH1641-scrapie.

    Science.gov (United States)

    Langeveld, Jan P M; Jacobs, Jorg G; Erkens, Jo H F; Baron, Thierry; Andréoletti, Olivier; Yokoyama, Takahashi; van Keulen, Lucien J M; van Zijderveld, Fred G; Davidse, Aart; Hope, Jim; Tang, Yue; Bossers, Alex

    2014-01-01

    Efforts to differentiate bovine spongiform encephalopathy (BSE) from scrapie in prion infected sheep have resulted in effective methods to decide about the absence of BSE. In rare instances uncertainties remain due to assumptions that BSE, classical scrapie and CH1641-a rare scrapie variant-could occur as mixtures. In field samples including those from fallen stock, triplex Western blotting analyses of variations in the molecular properties of the proteinase K resistant part of the disease‑associated form of prion protein (PrP(res)) represents a powerful tool for quick discrimination purposes. In this study we examined 7 deviant ovine field cases of scrapie for some typical molecular aspects of PrP(res) found in CH1641‑scrapie, classical scrapie and BSE. One case was most close to scrapie with respect to molecular mass of its non-glycosylated fraction and N-terminally located 12B2‑epitope content. Two cases were unlike classical scrapie but too weak to differentiate between BSE or CH1641. The other 4 cases appeared intermediate between scrapie and CH1641 with a reduced molecular mass and 12B2‑epitope content, together with the characteristic presence of a second PrP(res) population. The existence of these 2 PrP(res) populations was further confirmed through deglycosylation by PNGaseF. The findings indicate that discriminatory diagnosis between classical scrapie, CH1641 and BSE can remain inconclusive with current biochemical methods. Whether such intermediate cases represent mixtures of TSE strains should be further investigated e.g. in bioassays with rodent lines that are varying in their susceptibility or other techniques suitable for strain typing.

  15. Protocol for further laboratory investigations into the distribution of infectivity of Atypical BSE

    Directory of Open Access Journals (Sweden)

    European Food Safety Authority

    2014-07-01

    Full Text Available Information on the pathogenesis and tissue distribution of Atypical Bovine Spongiform Encephalopathy (BSE in cattle through the study of field cases and experimental transmission studies is lacking. The latter are limited to transmission of Atypical BSE through intracerebral (i.c. inoculation of cattle. All data currently available relate to the presence or absence of PrPSc, but do not quantify relative amounts of PrPSc or levels of infectivity. A laboratory protocol for further studies is recommended, to allow the assessment of the relative infectious titre, PrPSc accumulation and prion seeding activity in the tissues of cattle that developed H-BSE or L-BSE (using posterior brainstem as a reference. Tissues to be covered by those studies are categorised in three priorities, based on their inclusion in the list of specific risk material in cattle, on the presence of infectivity, or PrPSc presence, demonstrated in Atypical BSEs or other Transmissible Spongiform Encephalopathies (TSEs in ruminants, and on the importance in terms of input into the food chain in the EU. The protocol provides details in terms of the minimum number of animals to be tested, processing and preparation of tissues, and methods to be used to identify abnormal PrP and quantify infectivity, also depending on the expected level of infectivity and amount of tissue available for analysis. It is recommended that, through the implementation of the protocol, information should also be obtained on the performance of currently validated rapid tests for TSE active surveillance in cattle/bioassay for detecting H-BSE and L-BSE agents.

  16. Atypical L-type bovine spongiform encephalopathy (L-BSE) transmission to cynomolgus macaques, a non-human primate.

    Science.gov (United States)

    Ono, Fumiko; Tase, Naomi; Kurosawa, Asuka; Hiyaoka, Akio; Ohyama, Atsushi; Tezuka, Yukio; Wada, Naomi; Sato, Yuko; Tobiume, Minoru; Hagiwara, Ken'ichi; Yamakawa, Yoshio; Terao, Keiji; Sata, Tetsutaro

    2011-01-01

    A low molecular weight type of atypical bovine spongiform encephalopathy (L-BSE) was transmitted to two cynomolgus macaques by intracerebral inoculation of a brain homogenate of cattle with atypical BSE detected in Japan. They developed neurological signs and symptoms at 19 or 20 months post-inoculation and were euthanized 6 months after the onset of total paralysis. Both the incubation period and duration of the disease were shorter than those for experimental transmission of classical BSE (C-BSE) into macaques. Although the clinical manifestations, such as tremor, myoclonic jerking, and paralysis, were similar to those induced upon C-BSE transmission, no premonitory symptoms, such as hyperekplexia and depression, were evident. Most of the abnormal prion protein (PrP(Sc)) was confined to the tissues of the central nervous system, as determined by immunohistochemistry and Western blotting. The PrP(Sc) glycoform that accumulated in the monkey brain showed a similar profile to that of L-BSE and consistent with that in the cattle brain used as the inoculant. PrP(Sc) staining in the cerebral cortex showed a diffuse synaptic pattern by immunohistochemistry, whereas it accumulated as fine and coarse granules and/or small plaques in the cerebellar cortex and brain stem. Severe spongiosis spread widely in the cerebral cortex, whereas florid plaques, a hallmark of variant Creutzfeldt-Jakob disease in humans, were observed in macaques inoculated with C-BSE but not in those inoculated with L-BSE.

  17. Improvement of goat TSE discriminative diagnosis and susceptibility based assessment of BSE infectivity in goat milk and meat

    NARCIS (Netherlands)

    Bossers, A.; Langeveld, J.P.M.

    2012-01-01

    In light of the known ability of the BSE agent to cross the animal/human species barrier, the evidence establishing the presence of BSE in goat is especially alarming, as it represents a potential risk of food-born contamination to human consumers of goat milk and meat products. The main objective h

  18. The BSE Risk of Processing Meat and Bone Meal in Nonruminant Feed: A Quantitative Assessment for the Netherlands

    NARCIS (Netherlands)

    Vos, de C.J.; Heres, L.

    2009-01-01

    The total ban on use of meat and bone meal (MBM) in livestock feed has been very successful in reducing bovine spongiform encephalopathy (BSE) spread, but also implies a waste of high-quality proteins resulting in economic and ecological loss. Now that the BSE epidemic is fading out, a partial lifti

  19. Bovine spongiform encephalopathy: is it time to relax BSE-related measures in the context of international trade?

    Science.gov (United States)

    Matthews, D; Adkin, A

    2011-04-01

    Bovine spongiform encephalopathy (BSE) has presented serious challenges to both the World Organisation for Animal Health and national governments, in defining and implementing appropriate national control measures, and in agreeing trade rules that permit safe trade in cattle and bovine products. Precautionary trade rules were initially necessary, based upon the science of sheep scrapie, but research into BSE later enabled BSE-specific trade rules to be developed. As a result, current rules on trade are underpinned by a sound body of knowledge on BSE. Declining epidemics in most affected countries confirm the appropriateness of current precautions. Nevertheless, risk is primarily dependent on the prevalence of infection with BSE. In the face of low prevalence scenarios, certain precautionary measures in the Terrestrial Animal Health Code may now be considered excessive. A thorough review is therefore deemed appropriate.

  20. Interpreting Space-Based Trends in Carbon Monoxide with Multiple Models

    Science.gov (United States)

    Strode, Sarah A.; Worden, Helen M.; Damon, Megan; Douglass, Anne R.; Duncan, Bryan N.; Emmons, Louisa K.; Lamarque, Jean-Francois; Manyin, Michael; Oman, Luke D.; Rodriguez, Jose M.; Strahan, Susan E.; Tilmes, Simone

    2016-01-01

    We use a series of chemical transport model and chemistry climate model simulations to investigate the observed negative trends in MOPITT CO over several regions of the world, and to examine the consistency of timedependent emission inventories with observations. We find that simulations driven by the MACCity inventory, used for the Chemistry Climate Modeling Initiative (CCMI), reproduce the negative trends in the CO column observed by MOPITT for 2000-2010 over the eastern United States and Europe. However, the simulations have positive trends over eastern China, in contrast to the negative trends observed by MOPITT. The model bias in CO, after applying MOPITT averaging kernels, contributes to the model-observation discrepancy in the trend over eastern China. This demonstrates that biases in a model's average concentrations can influence the interpretation of the temporal trend compared to satellite observations. The total ozone column plays a role in determining the simulated tropospheric CO trends. A large positive anomaly in the simulated total ozone column in 2010 leads to a negative anomaly in OH and hence a positive anomaly in CO, contributing to the positive trend in simulated CO. These results demonstrate that accurately simulating variability in the ozone column is important for simulating and interpreting trends in CO.

  1. Econometric Models, Methodology and Trends regarding public debt and external debt

    Directory of Open Access Journals (Sweden)

    Gheorghe Săvoiu

    2013-10-01

    Full Text Available Statistically-mathematically describing few econometric models as variables, this article approaches the impact and trends regarding public debt and external debt. Conceptually and practically analyzing the evolution of indicators, there are identified specific trends in the economy of Romania, some characteristic models are being parametrised and tested.

  2. Testing for integration using evolving trend and seasonal models: A Bayesian approach

    NARCIS (Netherlands)

    G. Koop (Gary); H.K. van Dijk (Herman)

    1999-01-01

    textabstractIn this paper, we make use of state space models to investigate the presence of stochastic trends in economic time series. A model is specified where such a trend can enter either in the autoregressive representation or in a separate state equation. Tests based on the former are

  3. Can a global model reproduce observed trends in summertime surface ozone levels?

    Directory of Open Access Journals (Sweden)

    S. Koumoutsaris

    2012-01-01

    Full Text Available Quantifying trends in surface ozone concentrations are critical for assessing pollution control strategies. Here we use observations and results from a global chemical transport model to examine the trends (1991–2005 in daily maximum 8-hour average concentrations in summertime surface ozone at rural sites in Europe and the United States. We find a decrease in observed ozone concentrations at the high end of the probability distribution at many of the sites in both regions. The model attributes these trends to a decrease in local anthropogenic ozone precursors, although simulated decreasing trends are overestimated in comparison with observed ones. The low end of observed distribution show small upward trends over Europe and the western US and downward trends in Eastern US. The model cannot reproduce these observed trends, especially over Europe and the western US. In particular, simulated changes between the low and high end of the distributions in these two regions are not significant. Sensitivity simulations indicate that emissions from far away source regions do not affect significantly ozone trends at both ends of the distribution. This is in contrast with previously available results, which indicated that increasing ozone trends at the low percentiles may reflect an increase in ozone background associated with increasing remote sources of ozone precursors. Possible reasons for discrepancies between observed and simulated trends are discussed.

  4. A Trend-Switching Financial Time Series Model with Level-Duration Dependence

    Directory of Open Access Journals (Sweden)

    Qingsheng Wang

    2012-01-01

    overcome the difficult problem that motivates our researches in this paper. An asymmetric and nonlinear model with the change of local trend depending on local high-low turning point process is first proposed in this paper. As the point process can be decomposed into the two different processes, a high-low level process and an up-down duration process, we then establish the so-called trend-switching model which depends on both level and duration (Trend-LD. The proposed model can predict efficiently the direction and magnitude of the local trend of a time series by incorporating the local high-low turning point information. The numerical results on six indices in world stock markets show that the proposed Trend-LD model is suitable for fitting the market data and able to outperform the traditional random walk model.

  5. Identification of the characteristics and risk factors of the BSE epidemic in the Netherlands.

    NARCIS (Netherlands)

    Heres, L.; Elbers, A.R.W.; Schreuder, B.E.C.; Zijderveld, van F.G.

    2007-01-01

    It is generally accepted that the bovine spongiform encephalopathy (BSE) epidemic is transmitted by feed contamination with meat and bone meal (MBM). Whether in some cases substances other than MBM have caused the spread of this disease cannot be excluded at present. Detailed knowledge about country

  6. BSE inoculation to prion diseases-resistant sheep reveals tricky silent carriers.

    Science.gov (United States)

    Ronzon, Frédéric; Bencsik, Anna; Lezmi, Stéphane; Vulin, Johann; Kodjo, Angeli; Baron, Thierry

    2006-12-01

    The possible transmission of bovine spongiform encephalopathy (BSE) agent to sheep contributed to select genetically sheep considered as resistant to prion diseases i.e., with PrP ARR/ARR genotype. Here, we report the infection of two PrP ARR/ARR genotype sheep using the cattle BSE agent inoculated by peripheral routes. Disease-associated prion protein (PrP(d)) was detected in the brain for one case (at 2191 days post-infection (dpi)) and only in the nervous enteric system for the other one (at 673dpi). The electrophoretic pattern of PrP(d) from the obex region in this BSE challenged sheep was shown to be closer from that found in naturally scrapie-affected sheep with regard to the apparent molecular mass of the unglycosylated PrP(d). Importantly, the absence of any clinical symptoms up to 6 years following experimental challenge suggests that silent carriers of the BSE agent may exist among ARR homozygous sheep.

  7. Inactivation of the BSE agent by the heat and pressure process for manufacturing gelatine

    NARCIS (Netherlands)

    Grobben, A.H.; Steele, P.J.; Somerville, R.A.; Taylor, D.; Schreuder, B.E.C.

    2005-01-01

    Dietary exposure to the bovine spongiform encephalopathy (BSE) agent is the probable cause of variant Creutzfeldt-Jakob disease in people. The industrial manufacturing process for the production of gelatine and colloidal protein by the heat and pressure process was downscaled accurately and its capa

  8. Rapid and discriminatory diagnosis of scrapie and BSE in retro-pharyngeal lymph nodes of sheep

    NARCIS (Netherlands)

    Langeveld, J.P.M.; Jacobs, J.G.; Erkens, J.H.F.; Bossers, A.; Zijderveld, van F.G.; Keulen, van L.J.M.

    2006-01-01

    Background Diagnosis based on prion detection in lymph nodes of sheep and goats can improve active surveillance for scrapie and, if it were circulating, for bovine spongiform encephalopathy (BSE). With sizes that allow repetitive testing and a location that is easily accessible at slaughter, retroph

  9. 9 CFR 93.436 - Ruminants from regions of minimal risk for BSE.

    Science.gov (United States)

    2010-01-01

    ... each animal's right hip, high on the tail-head (over the junction of the sacral and first cocygeal... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Ruminants from regions of minimal risk for BSE. 93.436 Section 93.436 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION...

  10. Evaluation of the cumulative evidence for freedom from BSE in birth cohorts

    DEFF Research Database (Denmark)

    Böhning, Dankmar; Greiner, Matthias

    2006-01-01

    Substantial resources are used for surveillance of bovine spongiform encephalopathy (BSE) despite an extremely low detection rate, especially in healthy slaughtered cattle. We have developed a method based on the geometric waiting time distribution to establish and update the statistical evidence...

  11. Trends in hydrodesulfurization catalysis based on realistic surface models

    DEFF Research Database (Denmark)

    Moses, P.G.; Grabow, L.C.; Fernandez Sanchez, Eva

    2014-01-01

    Trends in hydrodesulfurization (HDS) activity are investigated on the basis of surface properties calculated by density functional theory for a series of HDS catalysts. It is shown that approximately linear correlations exist between HS group binding energies and activation barriers of key elemen...

  12. Bovine spongiform encephalopathy (BSE): the end of the beginning or the beginning of the end?

    Science.gov (United States)

    Bradley, Ray; Liberski, Paweł P

    2004-01-01

    Bovine spongiform encephalopathy (BSE) is a zoonosis being the origin of variant Creutzfeldt-Jakob disease and an important cattle disease in its own right. This association has driven both the research into the disease and extensive epidemiological investigations of practical value. Not only has the occurrence of BSE has a serious effect on animal health and public health, it has also seriously interrupted trade in cattle and cattle products from affected countries. Since 2001, several additional European countries, Japan, Israel and Canada have reported BSE in native-born stock and this has led to a concern about the BSE status of countries that have imported cattle and cattle products from any affected country. A single case recently reported in the USA was in a cow imported from Canada, thus extending the risk of BSE occurrence into the North American continent as a whole. Extensive feed and offal bans have protected the food and feed chains in all countries with BSE, even though initially they tended to be leaky. Application of newly-developed, approved 'Rapid' tests for misfolded PrP in central nervous tissue of targeted, high-risk animals and slaughter cattle now provides the tools whereby the real incidence of the disease (and to a degree, infection) can be determined in an active surveillance programme. 'Rapid' testing also enables the progress of epidemics to be monitored in response to applied measures. In the EU, over 10 million cattle are tested annually. Analysis of the extensive data shows that it is the beginning of the end of the BSE epidemic in the UK; most European countries, Israel and Japan are close behind. The epidemic in North America (two cases to date) is at the beginning. Significant measures had already been adopted there to reduce the risk from recycling of infection via feed but it remains to be seen if they are watertight. Advice has been given to ensure that public health is protected and to monitor the epidemic by strategic use of

  13. Assessing trends and uncertainties in satellite-era ocean chlorophyll using space-time modeling

    Science.gov (United States)

    Hammond, Matthew L.; Beaulieu, Claudie; Sahu, Sujit K.; Henson, Stephanie A.

    2017-07-01

    The presence, magnitude, and even direction of long-term trends in phytoplankton abundance over the past few decades are still debated in the literature, primarily due to differences in the data sets and methodologies used. Recent work has suggested that the satellite chlorophyll record is not yet long enough to distinguish climate change trends from natural variability, despite the high density of coverage in both space and time. Previous work has typically focused on using linear models to determine the presence of trends, where each grid cell is considered independently from its neighbors. However, trends can be more thoroughly evaluated using a spatially resolved approach. Here a Bayesian hierarchical spatiotemporal model is fitted to quantify trends in ocean chlorophyll from September 1997 to December 2013. The approach used in this study explicitly accounts for the dependence between neighboring grid cells, which allows us to estimate trend by "borrowing strength" from the spatial correlation. By way of comparison, a model without spatial correlation is also fitted. This results in a notable loss of accuracy in model fit. Additionally, we find an order of magnitude smaller global trend, and larger uncertainty, when using the spatiotemporal model: -0.023 ± 0.12% yr-1 as opposed to -0.38 ± 0.045% yr-1 when the spatial correlation is not taken into account. The improvement in accuracy of trend estimates and the more complete account of their uncertainty emphasize the solution that space-time modeling offers for studying global long-term change.

  14. A Monte Carlo Uncertainty Analysis of Ozone Trend Predictions in a Two Dimensional Model. Revision

    Science.gov (United States)

    Considine, D. B.; Stolarski, R. S.; Hollandsworth, S. M.; Jackman, C. H.; Fleming, E. L.

    1998-01-01

    We use Monte Carlo analysis to estimate the uncertainty in predictions of total O3 trends between 1979 and 1995 made by the Goddard Space Flight Center (GSFC) two-dimensional (2D) model of stratospheric photochemistry and dynamics. The uncertainty is caused by gas-phase chemical reaction rates, photolysis coefficients, and heterogeneous reaction parameters which are model inputs. The uncertainty represents a lower bound to the total model uncertainty assuming the input parameter uncertainties are characterized correctly. Each of the Monte Carlo runs was initialized in 1970 and integrated for 26 model years through the end of 1995. This was repeated 419 times using input parameter sets generated by Latin Hypercube Sampling. The standard deviation (a) of the Monte Carlo ensemble of total 03 trend predictions is used to quantify the model uncertainty. The 34% difference between the model trend in globally and annually averaged total O3 using nominal inputs and atmospheric trends calculated from Nimbus 7 and Meteor 3 total ozone mapping spectrometer (TOMS) version 7 data is less than the 46% calculated 1 (sigma), model uncertainty, so there is no significant difference between the modeled and observed trends. In the northern hemisphere midlatitude spring the modeled and observed total 03 trends differ by more than 1(sigma) but less than 2(sigma), which we refer to as marginal significance. We perform a multiple linear regression analysis of the runs which suggests that only a few of the model reactions contribute significantly to the variance in the model predictions. The lack of significance in these comparisons suggests that they are of questionable use as guides for continuing model development. Large model/measurement differences which are many multiples of the input parameter uncertainty are seen in the meridional gradients of the trend and the peak-to-peak variations in the trends over an annual cycle. These discrepancies unambiguously indicate model formulation

  15. Calibration of a Bonner sphere extension (BSE) for high-energy neutron spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Howell, R.M., E-mail: rhowell@mdanderson.or [UT M.D. Anderson Cancer Center, 1515 Holcombe Blvd, Houston, TX 77030 (United States); Burgett, E.A. [Georgia Institute of Technology, 900 Atlantic Drive, Atlanta, GA (United States); Wiegel, B. [Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig (Germany); Hertel, N.E. [Georgia Institute of Technology, 900 Atlantic Drive, Atlanta, GA (United States)

    2010-12-15

    In a recent work, we constructed modular multisphere system which expands upon the design of an existing, commercially available Bonner sphere system by adding concentric shells of copper, tungsten, or lead. Our modular multisphere system is referred to as the Bonner Sphere Extension (BSE). The BSE was tested in a high energy neutron beam (thermal to 800 MeV) at Los Alamos Neutron Science Center and provided improvement in the measurement of the neutron spectrum in the energy regions above 20 MeV when compared to the standard BSS (and). However, when the initial test of the system was carried out at LANSCE, the BSE had not yet been calibrated. Therefore the objective of the present study was to perform calibration measurements. These calibration measurements were carried-out using monoenergetic neutron ISO 8529-1 reference beams at the Physikalisch-Technische Bundesanstalt (PTB), Braunschweig, Germany. The following monoenergetic reference beams were used for these experiments: 14.8 MeV, 1.2 MeV, 565 keV, and 144 keV. Response functions for the BSE were calculated using the Monte Carlo N-Particle Code, eXtended (MCNPX). The percent difference between the measured and calculated responses was calculated for each sphere and energy. The difference between measured and calculated responses for individual spheres ranged between 7.9% and 16.7% and the arithmetic mean for all spheres was (10.9 {+-} 1.8)%. These sphere specific correction factors will be applied for all future measurements carried out with the BSE.

  16. Calibration of a Bonner sphere extension (BSE) for high-energy neutron spectrometry.

    Science.gov (United States)

    Howell, R M; Burgett, E A; Wiegel, B; Hertel, N E

    2010-12-01

    In a recent work, we constructed modular multisphere system which expands upon the design of an existing, commercially available Bonner sphere system by adding concentric shells of copper, tungsten, or lead. Our modular multisphere system is referred to as the Bonner Sphere Extension (BSE). The BSE was tested in a high energy neutron beam (thermal to 800 MeV) at Los Alamos Neutron Science Center and provided improvement in the measurement of the neutron spectrum in the energy regions above 20 MeV when compared to the standard BSS (Burgett, 2008 and Howell et al., 2009).However, when the initial test of the system was carried-out at LANSCE, the BSE had not yet been calibrated. Therefore the objective of the present study was to perform calibration measurements. These calibration measurements were carried out using monoenergetic neutron ISO 8529-1 reference beams at the Physikalisch-Technische Bundesanstalt (PTB), Braunschweig, Germany. The following monoenergetic reference beams were used for these experiments: 14.8 MeV, 1.2 MeV, 565 keV, and 144 keV. Response functions for the BSE were calculated using the Monte Carlo N-Particle Code, eXtended (MCNPX). The percent difference between the measured and calculated responses was calculated for each sphere and energy. The difference between measured and calculated responses for individual spheres ranged between 7.9 % and 16.7 % and the arithmetic mean for all spheres was (10.9 ± 1.8) %. These sphere specific correction factors will be applied for all future measurements carried-out with the BSE.

  17. Tropospheric ozone trend over Beijing from 2002–2010: ozonesonde measurements and modeling analysis

    OpenAIRE

    Y. Wang; Konopka, P.; Liu, Y.; Chen, H; Müller, R.; F. Plöger; M. Riese; Cai, Z.; D. Lü

    2012-01-01

    Using a combination of ozonesonde data and numerical simulations of the Chemical Lagrangian Model of the Stratosphere (CLaMS), the trend of tropospheric ozone (O3) during 2002–2010 over Beijing was investigated. Tropospheric ozone over Beijing shows a winter minimum and a broad summer maximum with a clear positive trend in the maximum summer ozone concentration over the last decade. The observed significant trend of tropospheric column ozone for the entire time serie...

  18. Tropospheric ozone trend over Beijing from 2002–2010: ozonesonde measurements and modeling analysis

    OpenAIRE

    Wang, Y.; Konopka, P.; Liu, Y.; Chen, H; Müller, R.; F. Plöger; M. Riese; Cai, Z.; D. Lü

    2012-01-01

    Using a combination of ozonesonde data and numerical simulations of the Chemical Lagrangian Model of the Stratosphere (CLaMS), the trend of tropospheric ozone (O3) during 2002–2010 over Beijing was investigated. Tropospheric ozone over Beijing shows a winter minimum and a broad summer maximum with a clear positive trend in the maximum summer ozone concentration over the last decade. The observed significant trend of tropospheric column ozone is mainly caused by photoche...

  19. Simulation of Change Trend of Drought in Shaanxi Province in Future Based on PRECIS Model

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    [Objective] The aim was to predict the change trend of drought in Shaanxi Province in future. [Method] Based on the regional climate model PRECIS from Hadley Climate Center, British Meteorological Bureau, taking precipitation anomaly percentage as assessment index, the change trend of drought in Shaanxi Province in reference years (1971-1990) was simulated, and the change trend of drought in Shaanxi Province from 2071 to 2100 was predicted. [Result] The simulated value of drought frequency in reference year...

  20. Pan-European modelling of riverine nutrient concentrations - spatial patterns, source detection, trend analyses, scenario modelling

    Science.gov (United States)

    Bartosova, Alena; Arheimer, Berit; Capell, Rene; Donnelly, Chantal; Strömqvist, Johan

    2016-04-01

    Nutrient transport models are important tools for large scale assessments of macro-nutrient fluxes (nitrogen, phosphorus) and thus can serve as support tool for environmental assessment and management. Results from model applications over large areas, i.e. from major river basin to continental scales can fill a gap where monitoring data is not available. Here, we present results from the pan-European rainfall-runoff and nutrient transfer model E-HYPE, which is based on open data sources. We investigate the ability of the E-HYPE model to replicate the spatial and temporal variations found in observed time-series of riverine N and P concentrations, and illustrate the model usefulness for nutrient source detection, trend analyses, and scenario modelling. The results show spatial patterns in N concentration in rivers across Europe which can be used to further our understanding of nutrient issues across the European continent. E-HYPE results show hot spots with highest concentrations of total nitrogen in Western Europe along the North Sea coast. Source apportionment was performed to rank sources of nutrient inflow from land to sea along the European coast. An integrated dynamic model as E-HYPE also allows us to investigate impacts of climate change and measure programs, which was illustrated in a couple of scenarios for the Baltic Sea. Comparing model results with observations shows large uncertainty in many of the data sets and the assumptions used in the model set-up, e.g. point source release estimates. However, evaluation of model performance at a number of measurement sites in Europe shows that mean N concentration levels are generally well simulated. P levels are less well predicted which is expected as the variability of P concentrations in both time and space is higher. Comparing model performance with model set-ups using local data for the Weaver River (UK) did not result in systematically better model performance which highlights the complexity of model

  1. METHODOLOGICAL APPROACH AND MODEL ANALYSIS FOR IDENTIFICATION OF TOURIST TRENDS

    OpenAIRE

    Neven Šerić; Marijana Jurišić

    2015-01-01

    The draw and diversity of the destination’s offer is an antecedent of the tourism visits growth. The destination supply differentiation is carried through new, specialised tourism products. The usual approach consists of forming specialised tourism products in accordance with the existing tourism destination image. Another approach, prevalent in practice of developed tourism destinations is based on innovating the destination supply through accordance with the global tourism trends. For this ...

  2. Immunohistochemical and biochemical characteristics of BSE and CWD in experimentally infected European red deer (Cervus elaphus elaphus

    Directory of Open Access Journals (Sweden)

    Dagleish Mark P

    2009-07-01

    Full Text Available Abstract Background The cause of the bovine spongiform encephalopathy (BSE epidemic in the United Kingdom (UK was the inclusion of contaminated meat and bone meal in the protein rations fed to cattle. Those rations were not restricted to cattle but were also fed to other livestock including farmed and free living deer. Although there are no reported cases to date of natural BSE in European deer, BSE has been shown to be naturally or experimentally transmissible to a wide range of different ungulate species. Moreover, several species of North America's cervids are highly susceptible to chronic wasting disease (CWD, a transmissible spongiform encephalopathy (TSE that has become endemic. Should BSE infection have been introduced into the UK deer population, the CWD precedent could suggest that there is a danger for spread and maintenance of the disease in both free living and captive UK deer populations. This study compares the immunohistochemical and biochemical characteristics of BSE and CWD in experimentally-infected European red deer (Cervus elpahus elaphus. Results After intracerebral or alimentary challenge, BSE in red deer more closely resembled natural infection in cattle rather than experimental BSE in small ruminants, due to the lack of accumulation of abnormal PrP in lymphoid tissues. In this respect it was different from CWD, and although the neuropathological features of both diseases were similar, BSE could be clearly differentiated from CWD by immunohistochemical and Western blotting methods currently in routine use. Conclusion Red deer are susceptible to both BSE and CWD infection, but the resulting disease phenotypes are distinct and clearly distinguishable.

  3. Trend Validation of a Musculoskeletal Model with a Workstation Design Parameter

    CERN Document Server

    Pontonnier, Charles; Samani, Afshin; Dumont, Georges; Madeleine, Pascal

    2012-01-01

    The aim of this article is to present the application of a trend validation to validate a simulation model. The workstation parameter used to define the trend is the table height of simulated meat cutting tasks (well known to be related to MSD).

  4. The changing model of big pharma: impact of key trends.

    Science.gov (United States)

    Gautam, Ajay; Pan, Xiaogang

    2016-03-01

    Recent years have seen exciting breakthroughs in biomedical sciences that are producing truly novel therapeutics for unmet patient needs. However, the pharmaceutical industry is also facing significant barriers in the form of pricing and reimbursement, continued patent expirations and challenging market dynamics. In this article, we have analyzed data from the 1995-2015 period, on key aspects such as revenue distribution, research units, portfolio mix and emerging markets to identify four key trends that help to understand the change in strategic focus, realignment of R&D footprint, the shift from primary care toward specialty drugs and biologics and the growth of emerging markets as major revenue drivers for big pharma.

  5. Characterizing uncertainties in recent trends of global terrestrial net primary production through ensemble modeling

    Science.gov (United States)

    Wang, W.; Hashimoto, H.; Ganguly, S.; Votava, P.; Nemani, R. R.; Myneni, R. B.

    2010-12-01

    Large uncertainties exist in our understanding of the trends and variability in global net primary production (NPP) and its controls. This study attempts to address this question through a multi-model ensemble experiment. In particular, we drive ecosystem models including CASA, LPJ, Biome-BGC, TOPS-BGC, and BEAMS with a long-term climate dataset (i.e., CRU-NCEP) to estimate global NPP from 1901 to 2009 at a spatial resolution of 0.5 x 0.5 degree. We calculate the trends of simulated NPP during different time periods and test their sensitivities to climate variables of solar radiation, air temperature, precipitation, vapor pressure deficit (VPD), and atmospheric CO2 levels. The results indicate a large diversity among the simulated NPP trends over the past 50 years, ranging from nearly no trend to an increasing trend of ~0.1 PgC/yr. Spatial patterns of the NPP generally show positive trends in boreal forests, induced mainly by increasing temperatures in these regions; they also show negative trends in the tropics, although the spatial patterns are more diverse. These diverse trends result from different climatic sensitivities of NPP among the tested models. Depending the ecological processes (e.g., photosynthesis or respiration) a model emphasizes, it can be more or less responsive to changes in solar radiation, temperatures, water, or atmospheric CO2 levels. Overall, these results highlight the limit of current ecosystem models in simulating NPP, which cannot be easily observed. They suggest that the traditional single-model approach is not ideal for characterizing trends and variability in global carbon cycling.

  6. A storage model approach to the assessment of snow depth trends

    Science.gov (United States)

    Woody, Jonathan; Lund, Robert; Grundstein, Andrew J.; Mote, Thomas L.

    2009-10-01

    This paper introduces a stochastic storage model capable of assessing trends in daily snow depth series. The model allows for seasonal features, which permits the analysis of daily data. Breakpoint times, which occur when the observing station changes location or instrumentation, are shown to greatly influence estimated trend margins and are accounted for in this analysis. The model is fitted by numerically minimizing a sum of squares of daily prediction errors. Standard errors for the model parameters, useful in making trend inferences, are presented. The methods are illustrated in the analysis of a century of daily snow depth observations from Napoleon, North Dakota. The results here show that snow depths are significantly declining at Napoleon, with spring ablation occurring earlier, and that breakpoint features are very influential in deriving realistic trend estimates.

  7. An I(2) Cointegration Model with Piecewise Linear Trends: Likelihood Analysis and Application

    DEFF Research Database (Denmark)

    Kurita, Takamitsu; Nielsen, Heino Bohn; Rahbæk, Anders

    for the cointegration ranks, extending the result for I(2) models with a linear trend in Nielsen and Rahbek (2007) and for I(1) models with piecewise linear trends in Johansen, Mosconi, and Nielsen (2000). The provided asymptotic theory extends also the results in Johansen, Juselius, Frydman, and Goldberg (2009) where...... asymptotic inference is discussed in detail for one of the cointegration parameters. To illustrate, an empirical analysis of US consumption, income and wealth, 1965 - 2008, is performed, emphasizing the importance of a change in nominal price trends after 1980....

  8. Can a global model reproduce observed trends in summertime surface ozone levels?

    OpenAIRE

    S. Koumoutsaris; I. Bey

    2012-01-01

    Quantifying trends in surface ozone concentrations are critical for assessing pollution control strategies. Here we use observations and results from a global chemical transport model to examine the trends (1991–2005) in daily maximum 8-hour average concentrations in summertime surface ozone at rural sites in Europe and the United States. We find a decrease in observed ozone concentrations at the high end of the probability distribution at many of the sites in both regions. The model attribut...

  9. Effects of cognitive style and maintenance strategies on breast self-examination (BSE) practice by African American women.

    Science.gov (United States)

    Jacob, T C; Penn, N E; Kulik, J A; Spieth, L E

    1992-12-01

    A convenience sample of 159 African American women, 18-45 years old, was trained to perform breast self-examination (BSE) and was categorized according to the participants' cognitive style (monitors/blunters). Participants were then randomly assigned to one of four groups differing in BSE maintenance strategy (self-management, positive reinforcement, both, or neither). Self-reported monthly compliance with BSE was subsequently assessed during a 9-month period. A significant interaction between maintenance strategies and cognitive style was found. For blunters, the highest compliance rates and the highest competency scores occurred in the group with no maintenance strategy, whereas for monitors, the highest compliance rates and competency scores were found in the groups receiving positive reinforcement and/or self-management strategies. Additional results indicate that high levels of BSE competency were achieved across conditions and that competency improved over time.

  10. Sensitivity and specificity of a commercial BSE kit for the detection of ovine scrapie.

    Science.gov (United States)

    Yamamoto, Takuji; Ushiki-Kaku, Yuko; Yokoyama, Takashi; Hattori, Shunji

    2013-06-01

    To examine the sensitivity of a commercially available bovine spongiform encephalopathy (BSE) kit (NippIBL) for the detection of ovine scrapie, 50 scrapie-positive ovine samples from the UK, and 54 scrapie-negative ovine samples from Japan were obtain and tested using this kit. The sensitivity and specificity of NippIBL for ovine samples were 96% and 100%, respectively. The detection limit of the abnormal isoform of prion protein (PrP(Sc) ) of NippIBL was examined using diluted scrapie-positive samples. The sensitivity of NippIBL to ovine scrapie was 3-10 times superior to that of another commercial BSE diagnosis kit. Thus, the NippIBL kit proved more effective for the detection of ovine scrapie.

  11. Cows for fear: is BSE a threat to human health? Bovine spongiform encephalopathy.

    OpenAIRE

    Josephson, J

    1998-01-01

    In 1996, a new variant of Creutzfeldt-Jakob disease (vCJD)-a disease that causes lack of coordination, muscle twitching or jerking, dementia, and, eventually, death-suddenly appeared in Great Britain. It is believed that the victims contracted the disease from eating the beef of cattle stricken with bovine spongiform encephalopathy (BSE), or mad cow disease. As of December 1997, at least 25 people in the United Kingdom and France have contracted vCJD.

  12. Nachweis von zentralnervösem Gewebe in Lebensmitteln im Hinblick auf die bovine spongiforme Enzephalopathie (BSE)

    OpenAIRE

    2002-01-01

    m Hinblick auf die Problematik der bovinen spongiformen Enzephalopathie (BSE) und der daraus erwachsenden Sensibilisierung des Verbrauchers bezüglich der Zusammensetzung der Fleischerzeugnisse ist es notwendig, der Lebensmittelüberwachung ein geeignetes Kontrollverfahren der Roh- und Endprodukte an die Hand zu geben. Vorrangig ist die Einhaltung des Verarbeitungsverbots von Gewebe des zentralen Nervensystems (ZNS) in Lebensmitteln, da dies als Hauptinfektionsquelle der BSE angesehen ...

  13. ANALISIS SOAL JENJANG KOGNITIF TAKSONOMI BLOOM REVISI PADA BUKU SEKOLAH ELEKTRONIK (BSE BIOLOGI SMA

    Directory of Open Access Journals (Sweden)

    Aa Juhanda

    2016-11-01

    Penelitian ini bertujuan untuk menganalisis kemunculan soal jenjang kognitif Bloom Revisi pada Buku Sekolah Elektronik (BSE Biologi SMA. Subjek penelitian adalah 1.650 soal yang terdapat pada BSE Edisi 2009. Instrumen yang digunakan adalah lembar analisis dokumen yang di dalamnya memuat informasi seperti kode soal, soal, dan jenis tingkatan kognitif taksonomi Bloom Revisi. Analisis data dilakukan secara kuantitatif dan kualitatif. Hasil penelitian menunjukkan bahwa rerata persentase kemunculan cukup tinggi diperoleh pada soal yang mengembangkan keterampilan berpikir tingkat rendah (Lower-Order Thinking Skills yaitu soal C1 (mengingat sebesar 46,60% dan C2 (memahami sebesar 47,99%, meskipun untuk C3 (menerapkan persentasenya masih rendah (0,28%. Rerata persentase kemunculan soal yang mengembangkan keterampilan tingkat tinggi (Higher-Order Thinking Skills mulai dari soal C4 (menganalisis sampai dengan C6 (mencipta memiliki rerata persentase yang rendah. Oleh karena itu, kemunculan soal jenjang kognitif Bloom Revisi pada BSE khususnya yang mengembangkan Higher-Order Thinking Skills masih perlu untuk ditingkatkan.

  14. The effect of breast self-examination (Bse) education given to midwifery students on their knowledge and attitudes.

    Science.gov (United States)

    Beydağ, Kerime Derya; Yürügen, Birsen

    2010-01-01

    This study was conducted in a descriptive and half-experimental format in order to determine the effect of breast self-examination (BSE) education given to 103 midwifery students from Halic University Sciences of Health School Midwifery Department on their knowledge and attitudes. After legal permission was obtained from the institution and verbal participation consent from the students, data were obtained using demographic and knowledge surveys, applied twice before and after education by the researcher between May-June 2010 and evaluated with proportional calculations, Kruskal Wallis test, t-test and t-test for dependent groups. Mean age of the students is 20.2±1.52; 58.3% had no information about BSE and 73.8% were not doing BSE; 7.7% them stated that they had a family member with breast cancer. The knowledge level score was 43.2±10.6 before and 68.4±10.5 after the BSE education (p<0.05). A statistically significant difference persisted between the pre- and post-education scores taking knowledge, making BSE, and frequency of using BSE average scores of the students (p<0.05).

  15. Development and evaluation of multi-agent models predicting Twitter trends in multiple domains

    NARCIS (Netherlands)

    Attema, T.; Maanen, P.P. van; Meeuwissen, E.

    2015-01-01

    This paper concerns multi-agent models predicting Twitter trends. We use a step-wise approach to develop a novel agent-based model with the following properties: (1) it uses individual behavior parameters for a set of Twitter users and (2) it uses a retweet graph to model the underlying social

  16. City Logistics Modeling Efforts: Trends and Gaps - A Review

    NARCIS (Netherlands)

    Anand, N.R.; Quak, H.J.; Van Duin, J.H.R.; Tavasszy, L.A.

    2012-01-01

    In this paper, we present a review of city logistics modeling efforts reported in the literature for urban freight analysis. The review framework takes into account the diversity and complexity found in the present-day city logistics practice. Next, it covers the different aspects in the modeling se

  17. Modeling Trends in Air Pollutant Concentrations over the ...

    Science.gov (United States)

    Regional model calculations over annual cycles have pointed to the need for accurately representing impacts of long-range transport. Linking regional and global scale models have met with mixed success as biases in the global model can propagate and influence regional calculations and often confound interpretation of model results. Since transport is efficient in the free-troposphere and since simulations over Continental scales and annual cycles provide sufficient opportunity for “atmospheric turn-over”, i.e., exchange between the free-troposphere and the boundary-layer, a conceptual framework is needed wherein interactions between processes occurring at various spatial and temporal scales can be consistently examined. The coupled WRF-CMAQ model is expanded to hemispheric scales and model simulations over period spanning 1990-current are analyzed to examine changes in hemispheric air pollution resulting from changes in emissions over this period. The National Exposure Research Laboratory (NERL) Atmospheric Modeling and Analysis Division (AMAD) conducts research in support of EPA mission to protect human health and the environment. AMAD research program is engaged in developing and evaluating predictive atmospheric models on all spatial and temporal scales for forecasting the air quality and for assessing changes in air quality and air pollutant exposures, as affected by changes in ecosystem management and regulatory decisions. AMAD is responsible for pr

  18. Latent risk and trend models for the evolution of annual fatality numbers in 30 European countries.

    Science.gov (United States)

    Dupont, Emmanuelle; Commandeur, Jacques J F; Lassarre, Sylvain; Bijleveld, Frits; Martensen, Heike; Antoniou, Constantinos; Papadimitriou, Eleonora; Yannis, George; Hermans, Elke; Pérez, Katherine; Santamariña-Rubio, Elena; Usami, Davide Shingo; Giustiniani, Gabriele

    2014-10-01

    In this paper a unified methodology is presented for the modelling of the evolution of road safety in 30 European countries. For each country, annual data of the best available exposure indicator and of the number of fatalities were simultaneously analysed with the bivariate latent risk time series model. This model is based on the assumption that the amount of exposure and the number of fatalities are intrinsically related. It captures the dynamic evolution in the fatalities as the product of the dynamic evolution in two latent trends: the trend in the fatality risk and the trend in the exposure to that risk. Before applying the latent risk model to the different countries it was first investigated and tested whether the exposure indicator at hand and the fatalities in each country were in fact related at all. If they were, the latent risk model was applied to that country; if not, a univariate local linear trend model was applied to the fatalities series only, unless the latent risk time series model was found to yield better forecasts than the univariate local linear trend model. In either case, the temporal structure of the unobserved components of the optimal model was established, and structural breaks in the trends related to external events were identified and captured by adding intervention variables to the appropriate components of the model. As a final step, for each country the optimally modelled developments were projected into the future, thus yielding forecasts for the number of fatalities up to and including 2020. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Past and present of analogue modelling, and its future trend

    Science.gov (United States)

    Koyi, Hemin

    2015-04-01

    Since Hull (1815) published his article on modelling, analogue modelling has expanded to simulate both a wider range of tectonic regimes and target more challenging set-ups, and has become an integrated part of the fields of tectonics and structural geology. Establishment of new laboratories testifies for the increased attention the technique receives. The ties between modellers and field geoscientists have become stronger with the focus being on understanding the parameters that govern the evolution of a tectonic regime and the processes that dominate it. Since the first sand castle was built with damp sand on a beach, sand has proven to be an appropriate material analogue. Even though granular materials is the most widely used analogue material, new materials are also (re)introduced as rock analogues. Emphasis has been on more precise measurements of the mechanical properties of the materials and on minimizing the preparation effects, which have a great impact on scaling, interpretations and benchmarking. The analytical technique used to quantify model results has also seen a great deal of improvement. In addition to X-ray tomography used to visualise internal structures of models, new techniques (e.g. PIV, high-resolution laser scanning, and interferometry) have enabled monitoring kinematics with a higher precision. Benchmarking exercises have given modelling an additional checking tool by outlining, in addition to the rheology of the modelling materials, the impact of different preparation approaches, the effect of boundary conditions, and the human factor on model results. However, despite the different approaches and deformation rigs, results of models of different tectonic laboratories have shown a great deal of similarities. Even with the introduction of more sophisticated numerical codes and usage of more powerful computers which enable the simulation of more challenging material properties and combinations of those, and 3D model set-up, analogue modelling

  20. Models of marine molluscan diseases: Trends and challenges.

    Science.gov (United States)

    Powell, Eric N; Hofmann, Eileen E

    2015-10-01

    Disease effects on host population dynamics and the transmission of pathogens between hosts are two important challenges for understanding how epizootics wax and wane and how disease influences host population dynamics. For the management of marine shellfish resources, marine diseases pose additional challenges in early intervention after the appearance of disease, management of the diseased population to limit a decline in host abundance, and application of measures to restrain that decline once it occurs. Mathematical models provide one approach for quantifying these effects and addressing the competing goals of managing the diseased population versus managing the disease. The majority of models for molluscan diseases fall into three categories distinguished by these competing goals. (1) Models that consider disease effects on the host population tend to focus on pathogen proliferation within the host. Many of the well-known molluscan diseases are pandemic, in that they routinely reach high prevalence rapidly over large geographic expanses, are characterized by transmission that does not depend upon a local source, and exert a significant influence on host population dynamics. Models focused on disease proliferation examine the influence of environmental change on host population metrics and provide a basis to better manage diseased stocks. Such models are readily adapted to questions of fishery management and habitat restoration. (2) Transmission models are designed to understand the mechanisms triggering epizootics, identify factors impeding epizootic development, and evaluate controls on the rate of disease spread over the host's range. Transmission models have been used extensively to study terrestrial diseases, yet little attention has been given to their potential for understanding the epidemiology of marine molluscan diseases. For management of diseases of wild stocks, transmission models open up a range of options, including the application of area

  1. Modelling trends in tropical column ozone with the UKCA chemistry-climate model

    Science.gov (United States)

    Keeble, James; Bednarz, Ewa; Banerjee, Antara; Abraham, Luke; Harris, Neil; Maycock, Amanda; Pyle, John

    2016-04-01

    Trends in tropical column ozone under a number of different emissions scenarios are explored with the UM-UKCA coupled chemistry climate model. A transient 1960-2100 simulation was run following the RCP6 scenario. Tropical averaged (10S-10N) total column ozone values decrease from the 1970s, reaching a minimum around 2000, and return to their 1980 values around 2040, consistent with the use and emission of ozone depleting substances, and their later controls under the Montreal Protocol. However, when the total column is subdivided into three partial columns, extending from the surface to the tropopause, the tropopause to 30km, and 30km to 50km, significant differences to the total column trend are seen. Modelled tropospheric column values increase from 1960-2000 before remaining steady throughout the 21st Century. Lower stratospheric column values decrease rapidly from 1960-2000, remain steady until 2050 before slowly decreasing to 2100, never recovering to their 1980s values. Upper stratospheric values decrease from 1960-2000, before rapidly increasing throughout the 21st Century, recovering to 1980s values by ~2020 and are significantly increased above the 1980s values by 2100. Using a series of idealised model simulations with varying concentrations of greenhouse gases and ozone depleting substances, we assess the physical processes driving the partial column response in the troposphere, lower stratosphere and upper stratosphere, and assess how these processes change under different emissions scenarios. Finally, we present a simple, linearised model for predicting tropical column ozone values based on greenhouse gas and ozone depleting substance scenarios.

  2. Turbulent Combustion Modeling Advances, New Trends and Perspectives

    CERN Document Server

    Echekki, Tarek

    2011-01-01

    Turbulent combustion sits at the interface of two important nonlinear, multiscale phenomena: chemistry and turbulence. Its study is extremely timely in view of the need to develop new combustion technologies in order to address challenges associated with climate change, energy source uncertainty, and air pollution. Despite the fact that modeling of turbulent combustion is a subject that has been researched for a number of years, its complexity implies that key issues are still eluding, and a theoretical description that is accurate enough to make turbulent combustion models rigorous and quantitative for industrial use is still lacking. In this book, prominent experts review most of the available approaches in modeling turbulent combustion, with particular focus on the exploding increase in computational resources that has allowed the simulation of increasingly detailed phenomena. The relevant algorithms are presented, the theoretical methods are explained, and various application examples are given. The book ...

  3. Intercomparison of temperature trends in IPCC CMIP5 simulations with observations, reanalyses and CMIP3 models

    Directory of Open Access Journals (Sweden)

    J. Xu

    2013-10-01

    Full Text Available On the basis of the fifth Coupled Model Intercomparison Project (CMIP5 and the climate model simulations covering 1979 through 2005, the temperature trends and their uncertainties have been examined to note the similarities or differences compared to the radiosonde observations, reanalyses and the third Coupled Model Intercomparison Project (CMIP3 simulations. The results show noticeable discrepancies for the estimated temperature trends in the four data groups (radiosonde, reanalysis, CMIP3 and CMIP5, although similarities can be observed. Compared to the CMIP3 model simulations, the simulations in some of the CMIP5 models were improved. The CMIP5 models displayed a negative temperature trend in the stratosphere closer to the strong negative trend seen in the observations. However, the positive tropospheric trend in the tropics is overestimated by the CMIP5 models relative to CMIP3 models. While some of the models produce temperature trend patterns more highly correlated with the observed patterns in CMIP5, the other models (such as CCSM4 and IPSL_CM5A-LR exhibit the reverse tendency. The CMIP5 temperature trend uncertainty was significantly reduced in most areas, especially in the Arctic and Antarctic stratosphere, compared to the CMIP3 simulations. Similar to the CMIP3, the CMIP5 simulations overestimated the tropospheric warming in the tropics and Southern Hemisphere and underestimated the stratospheric cooling. The crossover point where tropospheric warming changes into stratospheric cooling occurred near 100 hPa in the tropics, which is higher than in the radiosonde and reanalysis data. The result is likely related to the overestimation of convective activity over the tropical areas in both the CMIP3 and CMIP5 models. Generally, for the temperature trend estimates associated with the numerical models including the reanalyses and global climate models, the uncertainty in the stratosphere is much larger than that in the troposphere, and the

  4. A quantitative assessment of the BSE risk associated with fly ash and slag from the incineration of meat-and-bone meal in a gas-fired power plant in Denmark.

    Science.gov (United States)

    Paisley, Larry G; Hostrup-Pedersen, Julie

    2005-05-10

    It has been recommended that meat-and-bone meal (MBM) be incinerated at 850 degrees C for at least 2s and the ashes and slag disposed of in controlled landfills, to dispose of animal-derived proteins. Most commonly, the MBM is incinerated in cement works or coal-fired power plants and the ashes and slag are incorporated into the cement or concrete. Our goal was to assess with a Monte Carlo simulation model the bovine spongiform encephalopathy (BSE) risk to cattle and humans posed by the ash and slag. The results will be used by decision makers to evaluate the need for disposal of the fly ash in controlled landfills and the feasibility of use of the ash by the phosphate and fertilizer industries. We assumed that all specified risk material (SRM) and MBM produced in Denmark would be incinerated in this gas-fired power plant. Based on observations in 2001, we assumed that, on average, six (range: 0-15) clinical BSE cases each year were rendered into MBM and incinerated. In addition, SRM or carcasses from 0 to 31 (median=10) BSE-infected-but-undetected animals/BSE case were also incinerated. The simulations were run on a 1-week basis. Our results suggest that if the slag is collected and re-incinerated the median BSE infectivity remaining in the fly ash per week would be 3.1E-11 cattle ID(50). A cattle ID50 is the amount of infectivity that will cause infection in 50% of cattle exposed to it. During the weeks when BSE was infected in the SRM-MBM, the median infectivity in the fly ash was estimated as 8.7E-10 cattle ID50 and 2.9E-12 human ID50. The 95th percentiles were 2.1E-08 cattle ID50 and 5.8E-10 human ID50, respectively. One ton of fly ash would contain

  5. Hawaiian forest bird trends: using log-linear models to assess long-term trends is supported by model diagnostics and assumptions (reply to Freed and Cann 2013)

    Science.gov (United States)

    Camp, Richard J.; Pratt, Thane K.; Gorresen, P. Marcos; Woodworth, Bethany L.; Jeffrey, John J.

    2014-01-01

    Freed and Cann (2013) criticized our use of linear models to assess trends in the status of Hawaiian forest birds through time (Camp et al. 2009a, 2009b, 2010) by questioning our sampling scheme, whether we met model assumptions, and whether we ignored short-term changes in the population time series. In the present paper, we address these concerns and reiterate that our results do not support the position of Freed and Cann (2013) that the forest birds in the Hakalau Forest National Wildlife Refuge (NWR) are declining, or that the federally listed endangered birds are showing signs of imminent collapse. On the contrary, our data indicate that the 21-year long-term trends for native birds in Hakalau Forest NWR are stable to increasing, especially in areas that have received active management.

  6. Statistical modeling and trend detection of extreme sea level records in the Pearl River Estuary

    Science.gov (United States)

    Wang, Weiwen; Zhou, Wen

    2017-03-01

    Sea level rise has become an important issue in global climate change studies. This study investigates trends in sea level records, particularly extreme records, in the Pearl River Estuary, using measurements from two tide gauge stations in Macau and Hong Kong. Extremes in the original sea level records (daily higher high water heights) and in tidal residuals with and without the 18.6-year nodal modulation are investigated separately. Thresholds for defining extreme sea levels are calibrated based on extreme value theory. Extreme events are then modeled by peaks-over-threshold models. The model applied to extremes in original sea level records does not include modeling of their durations, while a geometric distribution is added to model the duration of extremes in tidal residuals. Realistic modeling results are recommended in all stationary models. Parametric trends of extreme sea level records are then introduced to nonstationary models through a generalized linear model framework. The result shows that, in recent decades, since the 1960s, no significant trends can be found in any type of extreme at any station, which may be related to a reduction in the influence of tropical cyclones in the region. For the longer-term record since the 1920s at Macau, a regime shift of tidal amplitudes around the 1970s may partially explain the diverse trend of extremes in original sea level records and tidal residuals.

  7. Recent trends of extreme precipitation indices in the Iberian Peninsula using observations and WRF model results

    Science.gov (United States)

    Bartolomeu, S.; Carvalho, M. J.; Marta-Almeida, M.; Melo-Gonçalves, P.; Rocha, A.

    2016-08-01

    Spatial and temporal distributions of the trends of extreme precipitation indices were analysed between 1986 and 2005, over the Iberian Peninsula (IP). The knowledge of the patterns of extreme precipitation is important for impacts assessment, development of adaptation and mitigation strategies. As such, there is a growing need for a more detailed knowledge of precipitation climate change. This analysis was performed for Portuguese and Spanish observational datasets and results performed by the Weather Research and Forecast (WRF) model forced by the ERA-Interim reanalysis. Extreme precipitation indices recommended by the Expert Team for Climate Change Detection Monitoring and Indices were computed, by year and season. Then, annual and seasonal trends of the indices were estimated by Theil-Sen method and their significance was tested by the Mann-Kendal test. Additionally, a second simulation forced by the Max Planck Institute Earth System Model (MPI-ESM), was considered. This second modelling configuration was created in order to assess its performance when simulating extremes of precipitation. The annual trends estimated for the 1986-2005, from the observational datasets and from the ERA-driven simulation reveal: 1) negative statistically significant trends of the CWD index in the Galicia and in the centre of the IP; 2) positive statistically significant trends of the CDD index over the south of the IP and negative statistically significant trends in Galicia, north and centre of Portugal; 3) positive statistically significant trends of the R75p index in some regions of the north of the IP; 4) positive statistically significant trends in the R95pTOT index in the Central Mountains Chain, Leon Mountains and in the north of Portugal. Seasonally, negative statistically significant trends of the CWD index were found in Galicia, in winter and in the south of the IP, in summer. Positive statistically significant trends of the CWD index were identified in the Leon Mountains

  8. Understanding Evapotranspiration Trends and their Driving Mechanisms: An investigation across CONUS based on numerical modeling

    Science.gov (United States)

    Parr, D.; Wang, G.; Fu, C.

    2015-12-01

    As shown by climate models, increasing global temperatures and enhanced greenhouse gas concentration such as CO2 have had major effects on the dynamics of the hydrologic cycle and the surface energy budget, in particular, on evapotranspiration (ET). ET has significant decadal variations whether it be regionally or globally and variations of ET have major environmental and socioeconomic impacts. A number of recent studies have found a global increase in annual mean ET around 7mm per year per decade from about 1982 to the late 1990s. These results correspond with what is expected from an intensification of the hydrological cycle. However, the increasing ET trend did not continue after 1998 and from 1998-2008 this global trend was replaced with a decreasing trend of similar magnitude. This study uses numerical modeling to investigate if similar changing ET trends emerge in the continental U.S and part of northern Mexico. After validating model simulated evaporative fluxes and comparing spatial patterns to the aforementioned studies, various changing trends of different signs are identified across the U.S., and specific regions with strong signals of change are chosen for further examination with the purpose of identifying the root causes of these changing trends and which variables are most influential towards change. Experimental simulations conducted to isolate the most influential factors towards ET reveal that precipitation amount as well as its characteristics have the greatest impact on the ET trends discovered, with other factors like wind and air temperatures displaying less influence over inter-annual trends. This study helps better understand terrestrial ET and it's interactions which will help facilitate better predictions of change in surface climate such as heatwaves and droughts as well as impacts on water resources.

  9. Tropospheric ozone trend over Beijing from 2002–2010: ozonesonde measurements and modeling analysis

    Directory of Open Access Journals (Sweden)

    Y. Wang

    2012-05-01

    Full Text Available Using a combination of ozonesonde data and numerical simulations of the Chemical Lagrangian Model of the Stratosphere (CLaMS, the trend of tropospheric ozone (O3 during 2002–2010 over Beijing was investigated. Tropospheric ozone over Beijing shows a winter minimum and a broad summer maximum with a clear positive trend in the maximum summer ozone concentration over the last decade. The observed significant trend of tropospheric column ozone for the entire time series is 4.6% yr−1 for a mean level of 52 DU. This trend is close to the significant trend of partial column ozone in the lower troposphere (0–3 km during summer (3.4% yr−1 for a mean level of 23 DU. Analysis of the CLaMS simulation shows that transport rather than chemistry drives most of the seasonality of tropospheric ozone. However, dynamical processes alone cannot explain the trend of tropospheric ozone in the observational data. Clearly enhanced ozone values and a negative vertical ozone gradient in the lower troposphere in the observational data emphasize the importance of photochemistry within the troposphere during spring and summer, and suggest that the photochemistry within the troposphere significantly contributed to the tropospheric ozone trend over Beijing during the last decade.

  10. Tropospheric ozone trend over Beijing from 2002–2010: ozonesonde measurements and modeling analysis

    Directory of Open Access Journals (Sweden)

    Y. Wang

    2012-09-01

    Full Text Available Using a combination of ozonesonde data and numerical simulations of the Chemical Lagrangian Model of the Stratosphere (CLaMS, the trend of tropospheric ozone (O3 during 2002–2010 over Beijing was investigated. Tropospheric ozone over Beijing shows a winter minimum and a broad summer maximum with a clear positive trend in the maximum summer ozone concentration over the last decade. The observed significant trend of tropospheric column ozone is mainly caused by photochemical production (3.1% yr−1 for a mean level of 52 DU. This trend is close to the significant trend of partial column ozone in the lower troposphere (0–3 km resulting from the enhanced photochemical production during summer (3.0% yr−1 for a mean level of 23 DU. Analysis of the CLaMS simulation shows that transport rather than chemistry drives most of the seasonality of tropospheric ozone. However, dynamical processes alone cannot explain the trend of tropospheric ozone in the observational data. Clearly enhanced ozone values and a negative vertical ozone gradient in the lower troposphere in the observational data emphasize the importance of photochemistry within the troposphere during spring and summer, and suggest that the photochemistry within the troposphere significantly contributes to the tropospheric ozone trend over Beijing during the last decade.

  11. Modelled long term trends of surface ozone over South Africa

    CSIR Research Space (South Africa)

    Naidoo, M

    2011-09-01

    Full Text Available /CAMx CAMx in NRE MM5 Past Future ? Retrospective Air quality ? CSIR 2010 Slide 5 New framework for air quality forecast ? CCAM/CAMx CAMx in NRE CCAM Past Future Future Air quality ? CSIR 2010 Slide 6 New research - air quality forecast... Current research focus ? The response of air quality to changes in climate ? Simulations on longer time scales ? Drive air quality models with long term forecasted meteorology ? Need a baseline (1989 ? 2009) ? To date: Initial testing and 2 years...

  12. Predicting soil acidification trends at Plynlimon using the SAFE model

    Directory of Open Access Journals (Sweden)

    B. Reynolds

    1997-01-01

    Full Text Available The SAFE model has been applied to an acid grassland site, located on base-poor stagnopodzol soils derived from Lower Palaeozoic greywackes. The model predicts that acidification of the soil has occurred in response to increased acid deposition following the industrial revolution. Limited recovery is predicted following the decline in sulphur deposition during the mid to late 1970s. Reducing excess sulphur and NOx deposition in 1998 to 40% and 70% of 1980 levels results in further recovery but soil chemical conditions (base saturation, soil water pH and ANC do not return to values predicted in pre-industrial times. The SAFE model predicts that critical loads (expressed in terms of the (Ca+Mg+K:Alcrit ratio for six vegetation species found in acid grassland communities are not exceeded despite the increase in deposited acidity following the industrial revolution. The relative growth response of selected vegetation species characteristic of acid grassland swards has been predicted using a damage function linking growth to soil solution base cation to aluminium ratio. The results show that very small growth reductions can be expected for 'acid tolerant' plants growing in acid upland soils. For more sensitive species such as Holcus lanatus, SAFE predicts that growth would have been reduced by about 20% between 1951 and 1983, when acid inputs were greatest. Recovery to c. 90% of normal growth (under laboratory conditions is predicted as acidic inputs decline.

  13. Causal Modeling--Path Analysis a New Trend in Research in Applied Linguistics

    Science.gov (United States)

    Rastegar, Mina

    2006-01-01

    This article aims at discussing a new statistical trend in research in applied linguistics. This rather new statistical procedure is causal modeling--path analysis. The article demonstrates that causal modeling--path analysis is the best statistical option to use when the effects of a multitude of L2 learners' variables on language achievement are…

  14. New trends in interaction, virtual reality and modeling

    CERN Document Server

    Penichet, Victor MR; Gallud, José A

    2013-01-01

    The interaction between a user and a device forms the foundation of today's application design.Covering the following topics: * A suite of five structural principles helping designers to structure their mockups;* An agile method for exploiting desktop eye tracker equipment in combination with mobile devices;* An approach to explore large-scale collections based on classification systems;* A framework based on the use of modeling and components composition techniques to simplify the development of organizational collaborative systems;* A low-cost virtual reality system that provides highly sati

  15. A comparison of ozone trends from SME and SBUV satellite observations and model calculations

    Science.gov (United States)

    Rusch, D. W.; Clancy, R. T.

    1988-01-01

    Data on monthly ozone abundance trends near the stratopause, observed by the Ultraviolet Spectrometer (UVS) on the SME and by the Solar Backscatter Ultraviolet Instrument (SBUV) on NIMBUS-7 are presented for June, September, and January of the years 1982-1986. Globally averaged trends determined from the SME data (-0.5 + or - 1.3 percent/yr) were found to fall within model calculations by Rusch and Clancy (1988); the SBUV trends, on the other hand, were found to exceed maximum predicted ozone decreases by a factor of 3 or more. Detailed comparison of the two data sets indicated that an absolute offset of 3 percent/yr accounts for much of the difference between the two trends; the offset is considered to be due to incomplete characterization of the SBUV calibration drift. Both the UVS and SBUV data exhibited similar seasonal and latitudinal variations in ozone trends, which were reproduced by photochemical model calculations that included latitude-dependent NMC temperature trends over the 1982-1986 period.

  16. Application of multivariate storage model to quantify trends in seasonally frozen soil

    Directory of Open Access Journals (Sweden)

    Woody Jonathan

    2016-06-01

    Full Text Available This article presents a study of the ground thermal regime recorded at 11 stations in the North Dakota Agricultural Network. Particular focus is placed on detecting trends in the annual ground freeze process portion of the ground thermal regime’s daily temperature signature. A multivariate storage model from queuing theory is fit to a quantity of estimated daily depths of frozen soil. Statistical inference on a trend parameter is obtained by minimizing a weighted sum of squares of a sequence of daily one-step-ahead predictions. Standard errors for the trend estimates are presented. It is shown that the daily quantity of frozen ground experienced at these 11 sites exhibited a negative trend over the observation period.

  17. Application of multivariate storage model to quantify trends in seasonally frozen soil

    Science.gov (United States)

    Woody, Jonathan; Wang, Yan; Dyer, Jamie

    2016-06-01

    This article presents a study of the ground thermal regime recorded at 11 stations in the North Dakota Agricultural Network. Particular focus is placed on detecting trends in the annual ground freeze process portion of the ground thermal regime's daily temperature signature. A multivariate storage model from queuing theory is fit to a quantity of estimated daily depths of frozen soil. Statistical inference on a trend parameter is obtained by minimizing a weighted sum of squares of a sequence of daily one-step-ahead predictions. Standard errors for the trend estimates are presented. It is shown that the daily quantity of frozen ground experienced at these 11 sites exhibited a negative trend over the observation period.

  18. Hybrid model for forecasting time series with trend, seasonal and salendar variation patterns

    Science.gov (United States)

    Suhartono; Rahayu, S. P.; Prastyo, D. D.; Wijayanti, D. G. P.; Juliyanto

    2017-09-01

    Most of the monthly time series data in economics and business in Indonesia and other Moslem countries not only contain trend and seasonal, but also affected by two types of calendar variation effects, i.e. the effect of the number of working days or trading and holiday effects. The purpose of this research is to develop a hybrid model or a combination of several forecasting models to predict time series that contain trend, seasonal and calendar variation patterns. This hybrid model is a combination of classical models (namely time series regression and ARIMA model) and/or modern methods (artificial intelligence method, i.e. Artificial Neural Networks). A simulation study was used to show that the proposed procedure for building the hybrid model could work well for forecasting time series with trend, seasonal and calendar variation patterns. Furthermore, the proposed hybrid model is applied for forecasting real data, i.e. monthly data about inflow and outflow of currency at Bank Indonesia. The results show that the hybrid model tend to provide more accurate forecasts than individual forecasting models. Moreover, this result is also in line with the third results of the M3 competition, i.e. the hybrid model on average provides a more accurate forecast than the individual model.

  19. A 2cM genome-wide scan of European Holstein cattle affected by classical BSE

    Directory of Open Access Journals (Sweden)

    Prasad Aparna

    2010-03-01

    Full Text Available Abstract Background Classical bovine spongiform encephalopathy (BSE is an acquired prion disease that is invariably fatal in cattle and has been implicated as a significant human health risk. Polymorphisms that alter the prion protein of sheep or humans have been associated with variations in transmissible spongiform encephalopathy susceptibility or resistance. In contrast, there is no strong evidence that non-synonymous mutations in the bovine prion gene (PRNP are associated with classical BSE disease susceptibility. However, two bovine PRNP insertion/deletion polymorphisms, one within the promoter region and the other in intron 1, have been associated with susceptibility to classical BSE. These associations do not explain the full extent of BSE susceptibility, and loci outside of PRNP appear to be associated with disease incidence in some cattle populations. To test for associations with BSE susceptibility, we conducted a genome wide scan using a panel of 3,072 single nucleotide polymorphism (SNP markers on 814 animals representing cases and control Holstein cattle from the United Kingdom BSE epidemic. Results Two sets of BSE affected Holstein cattle were analyzed in this study, one set with known family relationships and the second set of paired cases with controls. The family set comprises half-sibling progeny from six sires. The progeny from four of these sires had previously been scanned with microsatellite markers. The results obtained from the current analysis of the family set yielded both some supporting and new results compared with those obtained in the earlier study. The results revealed 27 SNPs representing 18 chromosomes associated with incidence of BSE disease. These results confirm a region previously reported on chromosome 20, and identify additional regions on chromosomes 2, 14, 16, 21 and 28. This study did not identify a significant association near the PRNP in the family sample set. The only association found in the PRNP

  20. Trend modelling of wave parameters and application in onboard prediction of ship responses

    DEFF Research Database (Denmark)

    Montazeri, Najmeh; Nielsen, Ulrik Dam; Jensen, J. Juncher

    2015-01-01

    This paper presents a trend analysis for prediction of sea state parameters onboard shipsduring voyages. Given those parameters, a JONSWAP model and also the transfer functions, prediction of wave induced ship responses are thus made. The procedure is tested with full-scale data of an in-service ......This paper presents a trend analysis for prediction of sea state parameters onboard shipsduring voyages. Given those parameters, a JONSWAP model and also the transfer functions, prediction of wave induced ship responses are thus made. The procedure is tested with full-scale data of an in...

  1. Non-existence of Steady State Equilibrium in the Neoclassical Growth Model with a Longevity Trend

    DEFF Research Database (Denmark)

    Hermansen, Mikkel Nørlem

    of steady state equilibrium when considering the empirically observed trend in longevity. We extend a standard continuous time overlapping generations model by a longevity trend and are thereby able to study the properties of mortality-driven population growth. This turns out to be exceedingly complicated......Longevity has been increasing in the developed countries for almost two centuries and further increases are expected in the future. In the neoclassical growth models the case of population growth driven by fertility is well-known, whereas the properties of population growth caused by persistently...

  2. Evaluation of the possible transmission of BSE and scrapie to gilthead sea bream (Sparus aurata.

    Directory of Open Access Journals (Sweden)

    Evgenia Salta

    Full Text Available In transmissible spongiform encephalopathies (TSEs, a group of fatal neurodegenerative disorders affecting many species, the key event in disease pathogenesis is the accumulation of an abnormal conformational isoform (PrP(Sc of the host-encoded cellular prion protein (PrP(C. While the precise mechanism of the PrP(C to PrP(Sc conversion is not understood, it is clear that host PrP(C expression is a prerequisite for effective infectious prion propagation. Although there have been many studies on TSEs in mammalian species, little is known about TSE pathogenesis in fish. Here we show that while gilthead sea bream (Sparus aurata orally challenged with brain homogenates prepared either from a BSE infected cow or from scrapie infected sheep developed no clinical prion disease, the brains of TSE-fed fish sampled two years after challenge did show signs of neurodegeneration and accumulation of deposits that reacted positively with antibodies raised against sea bream PrP. The control groups, fed with brains from uninfected animals, showed no such signs. Remarkably, the deposits developed much more rapidly and extensively in fish inoculated with BSE-infected material than in the ones challenged with the scrapie-infected brain homogenate, with numerous deposits being proteinase K-resistant. These plaque-like aggregates exhibited congophilia and birefringence in polarized light, consistent with an amyloid-like component. The neurodegeneration and abnormal deposition in the brains of fish challenged with prion, especially BSE, raises concerns about the potential risk to public health. As fish aquaculture is an economically important industry providing high protein nutrition for humans and other mammalian species, the prospect of farmed fish being contaminated with infectious mammalian PrP(Sc, or of a prion disease developing in farmed fish is alarming and requires further evaluation.

  3. Evaluation of the possible transmission of BSE and scrapie to gilthead sea bream (Sparus aurata).

    Science.gov (United States)

    Salta, Evgenia; Panagiotidis, Cynthia; Teliousis, Konstantinos; Petrakis, Spyros; Eleftheriadis, Eleftherios; Arapoglou, Fotis; Grigoriadis, Nikolaos; Nicolaou, Anna; Kaldrymidou, Eleni; Krey, Grigorios; Sklaviadis, Theodoros

    2009-07-28

    In transmissible spongiform encephalopathies (TSEs), a group of fatal neurodegenerative disorders affecting many species, the key event in disease pathogenesis is the accumulation of an abnormal conformational isoform (PrP(Sc)) of the host-encoded cellular prion protein (PrP(C)). While the precise mechanism of the PrP(C) to PrP(Sc) conversion is not understood, it is clear that host PrP(C) expression is a prerequisite for effective infectious prion propagation. Although there have been many studies on TSEs in mammalian species, little is known about TSE pathogenesis in fish. Here we show that while gilthead sea bream (Sparus aurata) orally challenged with brain homogenates prepared either from a BSE infected cow or from scrapie infected sheep developed no clinical prion disease, the brains of TSE-fed fish sampled two years after challenge did show signs of neurodegeneration and accumulation of deposits that reacted positively with antibodies raised against sea bream PrP. The control groups, fed with brains from uninfected animals, showed no such signs. Remarkably, the deposits developed much more rapidly and extensively in fish inoculated with BSE-infected material than in the ones challenged with the scrapie-infected brain homogenate, with numerous deposits being proteinase K-resistant. These plaque-like aggregates exhibited congophilia and birefringence in polarized light, consistent with an amyloid-like component. The neurodegeneration and abnormal deposition in the brains of fish challenged with prion, especially BSE, raises concerns about the potential risk to public health. As fish aquaculture is an economically important industry providing high protein nutrition for humans and other mammalian species, the prospect of farmed fish being contaminated with infectious mammalian PrP(Sc), or of a prion disease developing in farmed fish is alarming and requires further evaluation.

  4. Evidence for link between modelled trends in Antarctic sea ice and underestimated westerly wind changes

    Science.gov (United States)

    Purich, Ariaan; Cai, Wenju; England, Matthew H.; Cowan, Tim

    2016-02-01

    Despite global warming, total Antarctic sea ice coverage increased over 1979-2013. However, the majority of Coupled Model Intercomparison Project phase 5 models simulate a decline. Mechanisms causing this discrepancy have so far remained elusive. Here we show that weaker trends in the intensification of the Southern Hemisphere westerly wind jet simulated by the models may contribute to this disparity. During austral summer, a strengthened jet leads to increased upwelling of cooler subsurface water and strengthened equatorward transport, conducive to increased sea ice. As the majority of models underestimate summer jet trends, this cooling process is underestimated compared with observations and is insufficient to offset warming in the models. Through the sea ice-albedo feedback, models produce a high-latitude surface ocean warming and sea ice decline, contrasting the observed net cooling and sea ice increase. A realistic simulation of observed wind changes may be crucial for reproducing the recent observed sea ice increase.

  5. Global epidemic trend of tuberculosis during 1990-2010: using segmented regression model.

    Science.gov (United States)

    Kazemnejad, Anoushiravan; Arsang Jang, Shahram; Amani, Firouz; Omidi, Alireza

    2014-01-01

    Tuberculosis (TB) is a pandemic disease. It is the second leading cause of death from infectious diseases after human immunodeficiency virus (HIV) in the world.The main objective of this paper was to determine and compare the epidemiology of TB incidence rate and its trend changes during 1990-2010 in six WHO regions regarding age, gender and income levels. The Average Annual Percent Change (AAPC) and Annual Percent Change (APC) of TB incidence, mortality, treatment-successes, case detection rates, as well as change points of trend was estimated using segmented regression model. The number of change points was selected by the permutation procedure based on likelihood ratio test. Two change points for global TB incidence rate trend with AAPC5years equaling -1.4 % was estimated, the maximum AAPC5years of six regions was attributed to the American region (-3.5%). AACP of TB treatment-successes rate for Eastern Mediterranean (+2.2), the Americas (+1.6), south East Asia (+.8) and Global (+1.1) were significant (P<0.05). Moreover AACP5years of TB case detection rate for South East Asia (+7.5), Eastern Mediterranean (+4.9), Africa (+2.8) and the Americas (+1.7) were significant (P<0.05). Globally, all of income categories had descending trend of TB incidence and mortality rate, except the upper-middle income level that had ascending incidence trend (AAPC=+0.7%). Globally, TB incidence and mortality rates have downturn trend and TB treatment successes and detection rates have upward trend, but their changes rate are insufficient to reach the goal of TB stop strategy. The economic levels have effect on trend, with no clear pattern, so it seems necessary that evaluation TB control programs based on characteristics of countries for reach TB control goals.

  6. Does adding risk-trends to survival models improve in-hospital mortality predictions? A cohort study

    Directory of Open Access Journals (Sweden)

    Forster Alan J

    2011-07-01

    Full Text Available Abstract Background Clinicians informally assess changes in patients' status over time to prognosticate their outcomes. The incorporation of trends in patient status into regression models could improve their ability to predict outcomes. In this study, we used a unique approach to measure trends in patient hospital death risk and determined whether the incorporation of these trend measures into a survival model improved the accuracy of its risk predictions. Methods We included all adult inpatient hospitalizations between 1 April 2004 and 31 March 2009 at our institution. We used the daily mortality risk scores from an existing time-dependent survival model to create five trend indicators: absolute and relative percent change in the risk score from the previous day; absolute and relative percent change in the risk score from the start of the trend; and number of days with a trend in the risk score. In the derivation set, we determined which trend indicators were associated with time to death in hospital, independent of the existing covariates. In the validation set, we compared the predictive performance of the existing model with and without the trend indicators. Results Three trend indicators were independently associated with time to hospital mortality: the absolute change in the risk score from the previous day; the absolute change in the risk score from the start of the trend; and the number of consecutive days with a trend in the risk score. However, adding these trend indicators to the existing model resulted in only small improvements in model discrimination and calibration. Conclusions We produced several indicators of trend in patient risk that were significantly associated with time to hospital death independent of the model used to create them. In other survival models, our approach of incorporating risk trends could be explored to improve their performance without the collection of additional data.

  7. Population trends for North American winter birds based on hierarchical models

    Science.gov (United States)

    Soykan, Candan U.; Sauer, John; Schuetz, Justin G.; LeBaron, Geoffrey S.; Dale, Kathy; Langham, Gary M.

    2016-01-01

    Managing widespread and persistent threats to birds requires knowledge of population dynamics at large spatial and temporal scales. For over 100 yrs, the Audubon Christmas Bird Count (CBC) has enlisted volunteers in bird monitoring efforts that span the Americas, especially southern Canada and the United States. We employed a Bayesian hierarchical model to control for variation in survey effort among CBC circles and, using CBC data from 1966 to 2013, generated early-winter population trend estimates for 551 species of birds. Selecting a subset of species that do not frequent bird feeders and have ≥25% range overlap with the distribution of CBC circles (228 species) we further estimated aggregate (i.e., across species) trends for the entire study region and at the level of states/provinces, Bird Conservation Regions, and Landscape Conservation Cooperatives. Moreover, we examined the relationship between ten biological traits—range size, population size, migratory strategy, habitat affiliation, body size, diet, number of eggs per clutch, age at sexual maturity, lifespan, and tolerance of urban/suburban settings—and CBC trend estimates. Our results indicate that 68% of the 551 species had increasing trends within the study area over the interval 1966–2013. When trends were examined across the subset of 228 species, the median population trend for the group was 0.9% per year at the continental level. At the regional level, aggregate trends were positive in all but a few areas. Negative population trends were evident in lower latitudes, whereas the largest increases were at higher latitudes, a pattern consistent with range shifts due to climate change. Nine of 10 biological traits were significantly associated with median population trend; however, none of the traits explained >34% of the deviance in the data, reflecting the indirect relationships between population trend estimates and species traits. Trend estimates based on the CBC are broadly congruent with

  8. What Do Observational Datasets Say about Modeled Tropospheric Temperature Trends since 1979?

    Directory of Open Access Journals (Sweden)

    David Douglass

    2010-09-01

    Full Text Available Updated tropical lower tropospheric temperature datasets covering the period 1979–2009 are presented and assessed for accuracy based upon recent publications and several analyses conducted here. We conclude that the lower tropospheric temperature (TLT trend over these 31 years is +0.09 ± 0.03 °C decade−1. Given that the surface temperature (Tsfc trends from three different groups agree extremely closely among themselves (~ +0.12 °C decade−1 this indicates that the “scaling ratio” (SR, or ratio of atmospheric trend to surface trend: TLT/Tsfc of the observations is ~0.8 ± 0.3. This is significantly different from the average SR calculated from the IPCC AR4 model simulations which is ~1.4. This result indicates the majority of AR4 simulations tend to portray significantly greater warming in the troposphere relative to the surface than is found in observations. The SR, as an internal, normalized metric of model behavior, largely avoids the confounding influence of short-term fluctuations such as El Niños which make direct comparison of trend magnitudes less confident, even over multi-decadal periods.

  9. Large-scale G W -BSE calculations with N3 scaling: Excitonic effects in dye-sensitized solar cells

    Science.gov (United States)

    Marsili, Margherita; Mosconi, Edoardo; De Angelis, Filippo; Umari, Paolo

    2017-02-01

    Excitonic effects due to electron-hole coupling play a fundamental role in renormalizing energy levels in dye sensitized and organic solar cells determining the driving force for electron extraction. We show that first-principles calculations based on many-body perturbation theory within the G W -BSE approach provide a quantitative picture of interfacial excited state energetics in organic dye-sensitized TiO2, delivering a general rule for evaluating relevant energy levels. To perform G W -BSE calculations in such large systems we introduce a scheme based on maximally localized Wannier' s functions. With this method the overall scaling of G W -BSE calculations is reduced from O (N4 ) to O (N3 ).

  10. Regional soil moisture simulation for Shaanxi Province using SWAT model validation and trend analysis

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The soil moisture in Shaanxi Province,a region with complex topography,is simulated using the distributed hydrological model Soil Water Assessment Tool(SWAT).Comparison and contrast of modeled and observed soil moisture show that the SWAT model can reasonably simulate the long-term trend in soil moisture and the spatiotemporal variability of soil moisture in the region.Comparisons to NCEP/NCAR and ERA40 reanalysis of soil moisture show that the trend of variability in soil moisture simulated by SWAT is more consistent with the observed.SWAT model results suggested that high soil moisture in surface soil layers appears in the southern Shaanxi with high vegetation cover,and the Qinling mountainous region with frequent orographic precipitation.In deeper soil layers,high soil moisture appears in the river basins and plains.The regional soil moisture showed a generally decreasing trend on all soil layers from 1951 to 2004,with a stronger and significant decreasing trend in deeper soil layers,especially in the northern parts of the province.

  11. Experimental transmission of bovine spongiform encephalopathy (BSE) to cynomolgus macaques, a non-human primate.

    Science.gov (United States)

    Ono, Fumiko; Terao, Keiji; Tase, Naomi; Hiyaoka, Akio; Ohyama, Atsushi; Tezuka, Yukio; Wada, Naomi; Kurosawa, Asuka; Sato, Yuko; Tobiume, Minoru; Hagiwara, Ken'ichi; Yamakawa, Yoshio; Sata, Tetsutaro

    2011-01-01

    Bovine spongiform encephalopathy (BSE) was transmitted to three macaques by intracerebral inoculation of a brain homogenate from affected cattle detected in Japan. All monkeys developed abnormal behavioral signs, such as intermittent anorexia and hyperekplexia, around 24 months after inoculation. Neuronal symptoms, such as tremor, myoclonic jerking, and paralysis, appeared 27-44 months after inoculation. These symptoms worsened and total paralysis ensued within a year after onset. The disease duration was approximately 8-12 months. Both the incubation period and the duration of disease were shortened in the secondary transmission experiment to macaques. Heavy accumulation of disease-causing conformer(s) of prion protein (PrP(Sc)), with a similar glycoform profile to the PrP(Sc) contained in the inoculum, and severe spongiform changes in the histology of the brain, confirmed the successful transmission of BSE to monkeys. Florid plaques, a characteristic histological hallmark of variant Creutzfeldt-Jakob disease, were prominent in the cerebral cortex, in which a prion antigen was detected by immunohistochemistry (IHC). PrP(Sc) was mostly confined to the central nervous system, although small amounts of PrP(Sc) accumulated in the peripheral nerves of monkeys, as detected by Western blotting (WB). Neither IHC nor WB detected PrP(Sc) in the lymphatic organs/tissues, such as the tonsils, spleen, and appendix.

  12. Predominant involvement of the cerebellum in guinea pigs infected with bovine spongiform encephalopathy (BSE).

    Science.gov (United States)

    Furuoka, H; Horiuchi, M; Yamakawa, Y; Sata, T

    2011-05-01

    This study reports the experimental transmission of bovine spongiform encephalopathy (BSE) to guinea pigs and describes the cerebellar lesions in these animals. Guinea pigs were inoculated intracerebrally with 10% brain homogenates from BSE-affected cattle. These animals were designated as the first passage. Second and third passages were subsequently performed. All guinea pigs developed infection at each passage. The mean incubation period of the first passage was 370 days post-infection (dpi) and this decreased to 307 dpi and 309 dpi for the second and third passages, respectively. Mild to severe spongiform degeneration and gliosis were observed in the cerebral cortex, thalamus and brainstem. In addition, the affected animals had marked pathological changes in the cerebellum characterized by severe cortical atrophy associated with Bergmann radial gliosis of the molecular layer and reduction in the width of the granular cell layer. Immunohistochemically, intense PrP(Sc) deposition and scattered plaque-like deposits were observed in the molecular and granular cell layers. Cerebellar lesions associated with severe atrophy of the cortex have not been reported in animal prion diseases, including in the experimental transmission of PrP(Sc) to small rodents. These lesions were similar to the lesions of human kuru or the VV2 variant of sporadic Creutzfeldt-Jakob disease, although typical kuru plaques or florid plaques were not observed in the affected animals.

  13. [The eradication of BSE: a touch stone for the veterinary services].

    Science.gov (United States)

    Perler, L; Guidon, D; Schmidt, J

    2002-12-01

    The eradication of BSE is proving to be a lengthy task. Undisputedly, it has become one of the highest priority tasks of the Veterinary Services in Europe since the disease first occurred in the mid eighties. However, the effects of the ongoing eradication effort also impair important economic agricultural sectors. Risk analysis has never before been such a critical tool in the decision-making processes for eradication of animal diseases, despite the problem that many risk analyses are being conducted in the face of incomplete knowledge about BSE. In the focus are the measures minimizing the risk for humans (such as the ban on specified risk material) and the measures implemented to prevent the spread of the disease in animals with the ban on feeding meat and bone meal to ruminants. Due to the long incubation period, implementation of insufficient measures may not be noticed for many years. Implementation of drastic measures is needed, if the eradication of the disease is to be pursued purposefully.

  14. Next generation population synthesis of accreting white dwarfs: I. Hybrid calculations using BSE + MESA

    CERN Document Server

    Chen, Hai-Liang; Yungelson, L R; Gilfanov, M; Han, Zhanwen

    2014-01-01

    Accreting, nuclear-burning white dwarfs have been deemed to be candidate progenitors of SNe Ia, and to account for supersoft X-ray sources, novae, etc. We have carried out a binary population synthesis (BPS) study of hydrogen-accreting WDs. First, we use the BPS code \\textsf{BSE} as a baseline for the commonly used "rapid" approach. Second, we apply a "hybrid" approach: we use \\textsf{BSE} to generate a population of WDs with non-degenerate companions on the verge of mass transfer. We then follow their evolution using the detailed stellar evolutionary code \\textsf{MESA}. We investigate the evolution of the number of rapidly accreting white dwarfs (RAWDs), stably nuclear-burning white dwarfs (SNBWDs), and the SNe Ia rate produced by "single-degenerate" systems (SD). The two algorithms differ significantly in the predicted numbers of SNBWDs at early and late times, and also in the delay time distribution (DTD) of SD SNe Ia. The differences in the treatment of mass transfer may partially account for differences ...

  15. Correlation between the Insertion/Deletion Mutations of Prion Protein Gene and BSE Susceptibility and Milk Performance in Dairy Cows

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    Objective To investigate the 23 bp and 12 bp insertion/deletion (indel) mutations within the bovine prion protein (PRNP) gene in Chinese dairy cows, and to detect the associations of two indel mutations with BSE susceptibility and milk performance. Methods Based on bovine PRNP gene sequence, two pairs of primers for testing the 23 bp and 12 bp indel mutations were designed. The PCR ampliifcation and agarose electrophoresis were carried out to distinguish the different genotypes within the mutations. Moreover, based on previous data from other cattle breeds and present genotypic and allelic frequencies of two indels mutations in this study, the corrections between the two indel mutations and BSE susceptibility were tested, as well as the relationships between the mutations and milk performance traits were analyzed in this study based on the statistical analyses. Results In the analyzed Chinese Holstein population, the frequencies of two“del”alleles in 23 bp and 12 bp indel muations were more frequent. The frequency of haplotype of 23del-12del was higher than those of 23del-12ins and 23ins-12del. From the estimated r2 and D’ values, two indel polymorphisms were linked strongly in the Holstein population (D’=57.5%, r2=0.257). Compared with the BSE-affected cattle populations from the reported data, the signiifcant differences of genotypic and allelic frequencies were found among present Holstein and some BSE-affected populations (P0.05). Conclusions These observations revealed that the inlfuence of two indel mutations within the bovine PRNP gene on BSE depended on the breed and they did not affect the milk production traits, which layed the foundation for future selection of resistant animals, and for improving health conditions for dairy breeding against BSE in China.

  16. Sediment transport modelling based on grain size trend analysis in Augusta Harbour (Sicily)

    Science.gov (United States)

    Barbera, Giuseppe; Feo, Roberto; Freni, Gabriele

    2015-12-01

    To support marine civil engineer in pollutant studies, sediment management or dredging operations, is useful to know how the sediments move in accumulation basin. This paper investigates the dynamic of the sediment path using a two-dimensional numeric model: the Grain Size Trend Analysis (GSTA). The GSTA was applied using GiSedTrend plugin, under GIS software. The case study is the Augusta Harbour, which is one of the most polluted Italian harbours. It is the marine part of the Site of National Interest (SNI) of Priolo Gargallo (Siracusa, Italy) and it can be hydrodynamically considered as a lagoon. Two scenarios were obtained by using different geostatistical criteria.

  17. Quantitative exposure assessment for the combustion of meat and bone meal derived from specified risk material in the context of BSE in Ireland.

    Science.gov (United States)

    Cummins, E J; Grace, P M; Fry, D J; McDonnell, K P; Colgan, S F; Ward, S M

    2002-11-01

    The probability and severity of an adverse event can be analyzed by quantitative exposure assessment (QEA). This methodology was applied to model the human health risks associated with the combustion of specified risk material (SRM) derived meat and bone meal (MBM) in a combustion facility. The identification of MBM and SRM as significant factors in the spread of bovine spongiform encephalopathy (BSE) has resulted in restrictions on their use and movement, and this has led to a requirement for alternative end-uses for these products. A stochastic (Latin Hypercube sampling) simulation model was developed to assess the exposure and hence the risks associated with the use of SRM-derived MBM in a combustion facility. The model simulates the potential infectivity pathways that SRM-derived MBM follows, including its production from animals potentially infected with sub-clinical BSE and subsequent processing of the material with segregation and heat treatments. A failure probability was included to take account of sub-optimal operating conditions. Two scenarios, reflecting the infectivity risk in different animal tissues as defined by the European Commission's scientific steering committee (SSC), were performed with 100,000 iterations of the model. Model results showed that the societal exposure to humans resulting from the combustion of SRM-derived MBM is extremely small (mean values ranging from 7.57 x 10(-6) ID50/year to 8.38 x 10(-5) ID50/year). The resulting societal risks are significantly less than the background societal risk of approximately 2.5 cases of sporadic CJD in Ireland each year. A sensitivity analysis revealed that the species barrier had a large impact on exposure calculations and hence should be the focus of further scientific investigation to reduce our uncertainty about this parameter. The model predicts that material spillage into untreated effluent represents the biggest risk to humans, indicating that efforts for risk mitigation should be focused

  18. Modelling spatial trends in sorghum breeding field trials using a two-dimensional P-spline mixed model.

    Science.gov (United States)

    Velazco, Julio G; Rodríguez-Álvarez, María Xosé; Boer, Martin P; Jordan, David R; Eilers, Paul H C; Malosetti, Marcos; van Eeuwijk, Fred A

    2017-07-01

    A flexible and user-friendly spatial method called SpATS performed comparably to more elaborate and trial-specific spatial models in a series of sorghum breeding trials. Adjustment for spatial trends in plant breeding field trials is essential for efficient evaluation and selection of genotypes. Current mixed model methods of spatial analysis are based on a multi-step modelling process where global and local trends are fitted after trying several candidate spatial models. This paper reports the application of a novel spatial method that accounts for all types of continuous field variation in a single modelling step by fitting a smooth surface. The method uses two-dimensional P-splines with anisotropic smoothing formulated in the mixed model framework, referred to as SpATS model. We applied this methodology to a series of large and partially replicated sorghum breeding trials. The new model was assessed in comparison with the more elaborate standard spatial models that use autoregressive correlation of residuals. The improvements in precision and the predictions of genotypic values produced by the SpATS model were equivalent to those obtained using the best fitting standard spatial models for each trial. One advantage of the approach with SpATS is that all patterns of spatial trend and genetic effects were modelled simultaneously by fitting a single model. Furthermore, we used a flexible model to adequately adjust for field trends. This strategy reduces potential parameter identification problems and simplifies the model selection process. Therefore, the new method should be considered as an efficient and easy-to-use alternative for routine analyses of plant breeding trials.

  19. Detecting temporal trends in species assemblages with bootstrapping procedures and hierarchical models

    Science.gov (United States)

    Gotelli, Nicholas J.; Dorazio, Robert M.; Ellison, Aaron M.; Grossman, Gary D.

    2010-01-01

    Quantifying patterns of temporal trends in species assemblages is an important analytical challenge in community ecology. We describe methods of analysis that can be applied to a matrix of counts of individuals that is organized by species (rows) and time-ordered sampling periods (columns). We first developed a bootstrapping procedure to test the null hypothesis of random sampling from a stationary species abundance distribution with temporally varying sampling probabilities. This procedure can be modified to account for undetected species. We next developed a hierarchical model to estimate species-specific trends in abundance while accounting for species-specific probabilities of detection. We analysed two long-term datasets on stream fishes and grassland insects to demonstrate these methods. For both assemblages, the bootstrap test indicated that temporal trends in abundance were more heterogeneous than expected under the null model. We used the hierarchical model to estimate trends in abundance and identified sets of species in each assemblage that were steadily increasing, decreasing or remaining constant in abundance over more than a decade of standardized annual surveys. Our methods of analysis are broadly applicable to other ecological datasets, and they represent an advance over most existing procedures, which do not incorporate effects of incomplete sampling and imperfect detection.

  20. Trend estimates of AERONET-observed and model-simulated AOT percentiles between 1993 and 2013

    Science.gov (United States)

    Yoon, Jongmin; Pozzer, Andrea; Chang, Dong Yeong; Lelieveld, Jos

    2016-04-01

    Recent Aerosol Optical thickness (AOT) trend studies used monthly or annual arithmetic means that discard details of the generally right-skewed AOT distributions. Potentially, such results can be biased by extreme values (including outliers). This study additionally uses percentiles (i.e., the lowest 5%, 25%, 50%, 75% and 95% of the monthly cumulative distributions fitted to Aerosol Robotic Network (AERONET)-observed and ECHAM/MESSy Atmospheric Chemistry (EMAC)-model simulated AOTs) that are less affected by outliers caused by measurement error, cloud contamination and occasional extreme aerosol events. Since the limited statistical representativeness of monthly percentiles and means can lead to bias, this study adopts the number of observations as a weighting factor, which improves the statistical robustness of trend estimates. By analyzing the aerosol composition of AERONET-observed and EMAC-simulated AOTs in selected regions of interest, we distinguish the dominant aerosol types and investigate the causes of regional AOT trends. The simulated and observed trends are generally consistent with a high correlation coefficient (R = 0.89) and small bias (slope±2σ = 0.75 ± 0.19). A significant decrease in EMAC-decomposed AOTs by water-soluble compounds and black carbon is found over the USA and the EU due to environmental regulation. In particular, a clear reversal in the AERONET AOT trend percentiles is found over the USA, probably related to the AOT diurnal cycle and the frequency of wildfires.

  1. Trend Estimates of AERONET-Observed and Model-Simulated AOTs Between 1993 and 2013

    Science.gov (United States)

    Yoon, J.; Pozzer, A.; Chang, D. Y.; Lelieveld, J.; Kim, J.; Kim, M.; Lee, Y. G.; Koo, J.-H.; Lee, J.; Moon, K. J.

    2015-01-01

    Recently, temporal changes in Aerosol Optical Thickness (AOT) have been investigated based on model simulations, satellite and ground-based observations. Most AOT trend studies used monthly or annual arithmetic means that discard details of the generally right-skewed AOT distributions. Potentially, such results can be biased by extreme values (including outliers). This study additionally uses percentiles (i.e., the lowest 5%, 25%, 50%, 75% and 95% of the monthly cumulative distributions fitted to Aerosol Robotic Network (AERONET)-observed and ECHAM/MESSy Atmospheric Chemistry (EMAC)-model simulated AOTs) that are less affected by outliers caused by measurement error, cloud contamination and occasional extreme aerosol events. Since the limited statistical representativeness of monthly percentiles and means can lead to bias, this study adopts the number of observations as a weighting factor, which improves the statistical robustness of trend estimates. By analyzing the aerosol composition of AERONET-observed and EMAC-simulated AOTs in selected regions of interest, we distinguish the dominant aerosol types and investigate the causes of regional AOT trends. The simulated and observed trends are generally consistent with a high correlation coefficient (R = 0.89) and small bias (slope+/-2(sigma) = 0.75 +/- 0.19). A significant decrease in EMAC-decomposed AOTs by water-soluble compounds and black carbon is found over the USA and the EU due to environmental regulation. In particular, a clear reversal in the AERONET AOT trend percentiles is found over the USA, probably related to the AOT diurnal cycle and the frequency of wildfires. In most of the selected regions of interest, EMAC-simulated trends are mainly attributed to the significant changes of the dominant aerosols; e.g., significant decrease in sea salt and water soluble compounds over Central America, increase in dust over Northern Africa and Middle East, and decrease in black carbon and organic carbon over

  2. Modeling Systematic Change in Stopover Duration Does Not Improve Bias in Trends Estimated from Migration Counts.

    Directory of Open Access Journals (Sweden)

    Tara L Crewe

    Full Text Available The use of counts of unmarked migrating animals to monitor long term population trends assumes independence of daily counts and a constant rate of detection. However, migratory stopovers often last days or weeks, violating the assumption of count independence. Further, a systematic change in stopover duration will result in a change in the probability of detecting individuals once, but also in the probability of detecting individuals on more than one sampling occasion. We tested how variation in stopover duration influenced accuracy and precision of population trends by simulating migration count data with known constant rate of population change and by allowing daily probability of survival (an index of stopover duration to remain constant, or to vary randomly, cyclically, or increase linearly over time by various levels. Using simulated datasets with a systematic increase in stopover duration, we also tested whether any resulting bias in population trend could be reduced by modeling the underlying source of variation in detection, or by subsampling data to every three or five days to reduce the incidence of recounting. Mean bias in population trend did not differ significantly from zero when stopover duration remained constant or varied randomly over time, but bias and the detection of false trends increased significantly with a systematic increase in stopover duration. Importantly, an increase in stopover duration over time resulted in a compounding effect on counts due to the increased probability of detection and of recounting on subsequent sampling occasions. Under this scenario, bias in population trend could not be modeled using a covariate for stopover duration alone. Rather, to improve inference drawn about long term population change using counts of unmarked migrants, analyses must include a covariate for stopover duration, as well as incorporate sampling modifications (e.g., subsampling to reduce the probability that individuals will

  3. Trend estimates of AERONET-observed and model-simulated AOTs between 1993 and 2013

    Science.gov (United States)

    Yoon, J.; Pozzer, A.; Chang, D. Y.; Lelieveld, J.; Kim, J.; Kim, M.; Lee, Y. G.; Koo, J.-H.; Lee, J.; Moon, K. J.

    2016-01-01

    Recently, temporal changes in Aerosol Optical Thickness (AOT) have been investigated based on model simulations, satellite and ground-based observations. Most AOT trend studies used monthly or annual arithmetic means that discard details of the generally right-skewed AOT distributions. Potentially, such results can be biased by extreme values (including outliers). This study additionally uses percentiles (i.e., the lowest 5%, 25%, 50%, 75% and 95% of the monthly cumulative distributions fitted to Aerosol Robotic Network (AERONET)-observed and ECHAM/MESSy Atmospheric Chemistry (EMAC)-model simulated AOTs) that are less affected by outliers caused by measurement error, cloud contamination and occasional extreme aerosol events. Since the limited statistical representativeness of monthly percentiles and means can lead to bias, this study adopts the number of observations as a weighting factor, which improves the statistical robustness of trend estimates. By analyzing the aerosol composition of AERONET-observed and EMAC-simulated AOTs in selected regions of interest, we distinguish the dominant aerosol types and investigate the causes of regional AOT trends. The simulated and observed trends are generally consistent with a high correlation coefficient (R = 0.89) and small bias (slope±2σ = 0.75 ± 0.19). A significant decrease in EMAC-decomposed AOTs by water-soluble compounds and black carbon is found over the USA and the EU due to environmental regulation. In particular, a clear reversal in the AERONET AOT trend percentiles is found over the USA, probably related to the AOT diurnal cycle and the frequency of wildfires. In most of the selected regions of interest, EMAC-simulated trends are mainly attributed to the significant changes of the dominant aerosols; e.g., significant decrease in sea salt and water soluble compounds over Central America, increase in dust over Northern Africa and Middle East, and decrease in black carbon and organic carbon over Australia.

  4. Model-Based Attribution of High-Resolution Streamflow Trends in Two Alpine Basins of Western Austria

    Directory of Open Access Journals (Sweden)

    Christoph Kormann

    2016-02-01

    Full Text Available Several trend studies have shown that hydrological conditions are changing considerably in the Alpine region. However, the reasons for these changes are only partially understood and trend analyses alone are not able to shed much light. Hydrological modelling is one possible way to identify the trend drivers, i.e., to attribute the detected streamflow trends, given that the model captures all important processes causing the trends. We modelled the hydrological conditions for two alpine catchments in western Austria (a large, mostly lower-altitude catchment with wide valley plains and a nested high-altitude, glaciated headwater catchment with the distributed, physically-oriented WaSiM-ETH model, which includes a dynamical glacier module. The model was calibrated in a transient mode, i.e., not only on several standard goodness measures and glacier extents, but also in such a way that the simulated streamflow trends fit with the observed ones during the investigation period 1980 to 2007. With this approach, it was possible to separate streamflow components, identify the trends of flow components, and study their relation to trends in atmospheric variables. In addition to trends in annual averages, highly resolved trends for each Julian day were derived, since they proved powerful in an earlier, data-based attribution study. We were able to show that annual and highly resolved trends can be modelled sufficiently well. The results provide a holistic, year-round picture of the drivers of alpine streamflow changes: Higher-altitude catchments are strongly affected by earlier firn melt and snowmelt in spring and increased ice melt throughout the ablation season. Changes in lower-altitude areas are mostly caused by earlier and lower snowmelt volumes. All highly resolved trends in streamflow and its components show an explicit similarity to the local temperature trends. Finally, results indicate that evapotranspiration has been increasing in the lower

  5. Examining secular trend  and seasonality in count data using dynamic generalized linear modelling

    DEFF Research Database (Denmark)

    Lundbye-Christensen, Søren; Dethlefsen, Claus; Gorst-Rasmussen, Anders;

    series regression model for Poisson counts. It differs in allowing the regression coefficients to vary gradually over time in a random fashion. Data  In the period January 1980 to 1999, 17,989 incidents of acute myocardial infarction were recorded in the county of Northern Jutland, Denmark. Records were...... updated daily. Results  The model with a seasonal pattern and an approximately linear trend was fitted to the data, and diagnostic plots indicate a good model fit. The analysis with the dynamic model revealed peaks coinciding with influenza epidemics. On average the peak-to-trough ratio is estimated...

  6. Statistical modelling and power analysis for detecting trends in total suspended sediment loads

    Science.gov (United States)

    Wang, You-Gan; Wang, Shen S. J.; Dunlop, Jason

    2015-01-01

    The export of sediments from coastal catchments can have detrimental impacts on estuaries and near shore reef ecosystems such as the Great Barrier Reef. Catchment management approaches aimed at reducing sediment loads require monitoring to evaluate their effectiveness in reducing loads over time. However, load estimation is not a trivial task due to the complex behaviour of constituents in natural streams, the variability of water flows and often a limited amount of data. Regression is commonly used for load estimation and provides a fundamental tool for trend estimation by standardising the other time specific covariates such as flow. This study investigates whether load estimates and resultant power to detect trends can be enhanced by (i) modelling the error structure so that temporal correlation can be better quantified, (ii) making use of predictive variables, and (iii) by identifying an efficient and feasible sampling strategy that may be used to reduce sampling error. To achieve this, we propose a new regression model that includes an innovative compounding errors model structure and uses two additional predictive variables (average discounted flow and turbidity). By combining this modelling approach with a new, regularly optimised, sampling strategy, which adds uniformity to the event sampling strategy, the predictive power was increased to 90%. Using the enhanced regression model proposed here, it was possible to detect a trend of 20% over 20 years. This result is in stark contrast to previous conclusions presented in the literature.

  7. Temporal Topic Modeling to Assess Associations between News Trends and Infectious Disease Outbreaks

    Science.gov (United States)

    Ghosh, Saurav; Chakraborty, Prithwish; Nsoesie, Elaine O.; Cohn, Emily; Mekaru, Sumiko R.; Brownstein, John S.; Ramakrishnan, Naren

    2017-01-01

    In retrospective assessments, internet news reports have been shown to capture early reports of unknown infectious disease transmission prior to official laboratory confirmation. In general, media interest and reporting peaks and wanes during the course of an outbreak. In this study, we quantify the extent to which media interest during infectious disease outbreaks is indicative of trends of reported incidence. We introduce an approach that uses supervised temporal topic models to transform large corpora of news articles into temporal topic trends. The key advantages of this approach include: applicability to a wide range of diseases and ability to capture disease dynamics, including seasonality, abrupt peaks and troughs. We evaluated the method using data from multiple infectious disease outbreaks reported in the United States of America (U.S.), China, and India. We demonstrate that temporal topic trends extracted from disease-related news reports successfully capture the dynamics of multiple outbreaks such as whooping cough in U.S. (2012), dengue outbreaks in India (2013) and China (2014). Our observations also suggest that, when news coverage is uniform, efficient modeling of temporal topic trends using time-series regression techniques can estimate disease case counts with increased precision before official reports by health organizations.

  8. Analysis and prediction of rainfall trends over Bangladesh using Mann-Kendall, Spearman's rho tests and ARIMA model

    Science.gov (United States)

    Rahman, Mohammad Atiqur; Yunsheng, Lou; Sultana, Nahid

    2016-09-01

    In this study, 60-year monthly rainfall data of Bangladesh were analysed to detect trends. Modified Mann-Kendall, Spearman's rho tests and Sen's slope estimators were applied to find the long-term annual, dry season and monthly trends. Sequential Mann-Kendall analysis was applied to detect the potential trend turning points. Spatial variations of the trends were examined using inverse distance weighting (IDW) interpolation. AutoRegressive integrated moving average (ARIMA) model was used for the country mean rainfall and for other two stations data which depicted the highest and the lowest trend in the Mann-Kendall and Spearman's rho tests. Results showed that there is no significant trend in annual rainfall pattern except increasing trends for Cox's Bazar, Khulna, Satkhira and decreasing trend for Srimagal areas. For the dry season, only Bogra area represented significant decreasing trend. Long-term monthly trends demonstrated a mixed pattern; both negative and positive changes were found from February to September. Comilla area showed a significant decreasing trend for consecutive 3 months while Rangpur and Khulna stations confirmed the significant rising trends for three different months in month-wise trends analysis. Rangpur station data gave a maximum increasing trend in April whereas a maximum decreasing trend was found in August for Comilla station. ARIMA models predict +3.26, +8.6 and -2.30 mm rainfall per year for the country, Cox's Bazar and Srimangal areas, respectively. However, all the test results and predictions revealed a good agreement among them in the study.

  9. Poly-γ-glutamic acid productivity of Bacillus subtilis BsE1 has positive function in motility and biocontrol against Fusarium graminearum.

    Science.gov (United States)

    Wang, Luyao; Wang, Ning; Mi, Dandan; Luo, Yuming; Guo, Jianhua

    2017-07-01

    In this study, we investigate the relationship between γ-PGA productivity and biocontrol capacity of Bacillus subtilis BsE1; one bacterial isolate displayed 62.14% biocontrol efficacy against Fusarium root rot. The γ-PGA yield assay, motility assay, wheat root colonization assay, and biological control assay were analysed in different γ-PGA yield mutants of BsE1. The pgsB (PGA-synthase-CapB gene) deleted mutant of BsE1 reduced γ-PGA yield and exhibited apparent decline of in vitro motile ability. Deletion of pgsB impaired colonizing capacity of BsE1 on wheat root in 30 days, also lowered biocontrol efficacies from 62.08% (wild type BsE1) to 14.22% in greenhouse experiment against Fusarium root rot. The knockout of pgdS and ggt (genes relate to two γ-PGA degrading enzymes) on BsE1, leads to a considerable improvement in polymer yield and biocontrol efficacy, which attains higher level compared with wild type BsE1. Compared with ΔpgsB mutant, defense genes related to reactive oxygen species (ROS) and phytoalexin expressed changes by notable levels on wheat roots treated with BsE1, demonstrating the functional role γ-PGA plays in biocontrol against Fusarium root rot. γ-PGA is not only important to the motile and plant root colonization ability of BsE1, but also essential to the biological control performed by BsE1 against Fusarium root rot. Our goal in this study is to reveals a new perspective of BCAs screening on bacterial isolates, without good performance during pre-assays of antagonism ability.

  10. Anticorrelated observed and modeled trends in dissolved oceanic oxygen over the last 50 years

    Directory of Open Access Journals (Sweden)

    L. Stramma

    2012-04-01

    Full Text Available Observations and model runs indicate trends in dissolved oxygen (DO associated with current and ongoing global warming. However, a large-scale observation-to-model comparison has been missing and is presented here. This study presents a first global compilation of DO measurements covering the last 50 years. It shows declining upper-ocean DO levels in many regions, especially the tropical oceans, whereas areas with increasing trends are found in the subtropics and in some subpolar regions. For the Atlantic Ocean south of 20° N, the DO history could even be extended back to about 70 years, showing decreasing DO in the subtropical South Atlantic. The global mean DO trend between 50° S and 50° N at 300 dbar for the period 1960 to 2010 is −0.063 μmol kg−1 yr−1. Results of a numerical biogeochemical Earth system model reveal that the magnitude of the observed change is consistent with CO2-induced climate change. However, the correlation between simulated and observed patterns of past DO change is negative, indicating that the model does not correctly reproduce the processes responsible for observed regional oxygen changes in the past 50 years. A negative pattern correlation is also obtained for model configurations with particularly low and particularly high diapycnal mixing, for a configuration that assumes a CO2-induced enhancement of the C:N ratios of exported organic matter and irrespective of whether climatological or realistic winds from reanalysis products are used to force the model. Depending on the model configuration the 300 dbar DO trend between 50° S and 50° N is −0.026 to −0.046 μmol kg−1 yr−1. Although numerical models reproduce the overall sign and, to some extent, magnitude of observed ocean deoxygenation, this degree of realism does not necessarily apply to simulated regional patterns and the representation of processes involved in their generation

  11. ESEM-BSE coupled with rapid nano-scratching for micro-physicochemical analysis of marine exposed concrete

    NARCIS (Netherlands)

    Palin, D.; Thijssen, A.; Wiktor, V.; Jonkers, H.M.; Schlangen, H.E.J.G.

    2015-01-01

    Ordinary Portland cement (OPC) mortar specimens submerged in sea-water were analysed through environmental scanning electron microscopy (ESEM) in back scattered electron (BSE) mode and nano-scratching. Results from both sets of analysis show the presence of distinct phases associated with aragonite,

  12. ESEM-BSE coupled with rapid nano-scratching for micro-physicochemical analysis of marine exposed concrete

    NARCIS (Netherlands)

    Palin, D.; Thijssen, A.; Wiktor, V.; Jonkers, H.M.; Schlangen, H.E.J.G.

    2015-01-01

    Ordinary Portland cement (OPC) mortar specimens submerged in sea-water were analysed through environmental scanning electron microscopy (ESEM) in back scattered electron (BSE) mode and nano-scratching. Results from both sets of analysis show the presence of distinct phases associated with aragonite,

  13. Case Study on the Accounting Policies Used by Companies Listed on the Bucharest Stock Exchange (BSE) Tier I

    OpenAIRE

    Tãnasã Florentin; Prodan-Palade Doina

    2013-01-01

    The study analyzes the differences between the accounting policies of the companies listed on the BSE group and showed that there are differences between the accounting policies used by companies in different fields of activity. Mainly, differences can be seen between companies providing financial and insurance services, on the one hand, and those working in industry, on the other hand.

  14. Model simulated trend of surface carbon monoxide for the 2001-2010 decade

    Science.gov (United States)

    Yoon, J.; Pozzer, A.

    2014-05-01

    We present decadal trend estimates of surface carbon monoxide (CO), simulated using the atmospheric chemistry general circulation model ECHAM5/MESSy (EMAC) based on the emission scenarios, Representative Concentration Pathways (RCP) 8.5 for anthropogenic activity and Global Fire Emissions Database (GFED) v3.1 for biomass burning from 2001 through 2010. The spatial distribution of the modelled surface CO is evaluated with monthly Measurements Of Pollution In The Troposphere (MOPITT) thermal infrared product. The global means of correlation coefficient and relative bias for the 2001-2010 are 0.95 and -4.29%, respectively. We also find a reasonable correlation (R = 0.78) between the trends of EMAC surface CO and full 10 year monthly records from ground-based observation (World Data Centre for Greenhouse Gases, WDCGG). Over Western Europe, Eastern USA, and Northern Australia, the significant decreases of EMAC surface CO are estimated at -35.5 ± 5.8, -59.6 ± 9.1, and -13.7 ± 9.5 ppbv decade-1, respectively, with a 95% confidence interval. In contrast, the surface CO increases by +8.9 ± 4.8 ppbv decade-1 over South Asia. A high correlation (R = 0.92) between the significant changes in EMAC-simulated surface CO and total emission flux shows that the significant regional trends are attributed to the changes in primary/direct emissions from both anthropogenic activity and biomass burning. In particular, increasing trends of surface hydroxyl radical (OH) partially contribute to the decreasing trends of surface CO in Western Europe and Eastern USA.

  15. A retrospective study and predictive modelling of Newcastle Disease trends among rural poultry of eastern Zambia.

    Science.gov (United States)

    Mubamba, C; Ramsay, G; Abolnik, C; Dautu, G; Gummow, B

    2016-10-01

    Newcastle Disease (ND) is a highly infectious disease of poultry that seriously impacts on food security and livelihoods of livestock farmers and communities in tropical regions of the world. ND is a constant problem in the eastern province of Zambia which has more than 740 000 rural poultry. Very few studies give a situational analysis of the disease that can be used for disease control planning in the region. With this background in mind, a retrospective epidemiological study was conducted using Newcastle Disease data submitted to the eastern province headquarters for the period from 1989 to 2014. The study found that Newcastle Disease cases in eastern Zambia followed a seasonal and cyclic pattern with peaks in the hot dry season (Overall Seasonal Index 1.1) as well as cycles every three years with an estimated provincial incidence range of 0.16 to 1.7% per year. Annual trends were compared with major intervention policies implemented by the Zambian government, which often received donor support from the international community during the study period. Aid delivered through government programmes appeared to have no major impact on ND trends between 1989 and 2014 and reasons for this are discussed. There were apparent spatial shifts in districts with outbreaks over time which could be as a result of veterinary interventions chasing outbreaks rather than implementing uniform control. Data was also fitted to a predictive time series model for ND which could be used to plan for future ND control. Time series modelling showed an increasing trend in ND annual incidence over 25 years if existing interventions continue. A different approach to controlling the disease is needed if this trend is to be halted. Conversely, the positive trend may be a function of improved reporting by farmers as a result of more awareness of the disease.

  16. Modelling trends in woody vegetation structure in semi-arid Australia as determined from aerial photography.

    Science.gov (United States)

    Fensham, Roderick John; Low Choy, Sama J; Fairfax, Russell James; Cavallaro, Paul C

    2003-08-01

    Accounting of carbon stocks in woody vegetation for greenhouse purposes requires definition of medium term trends with accurate error assessment. Tree and shrub cover was sampled through time at randomly located sites over a large area of central Queensland, Australia using aerial photography from 1945 to 1999. Calibration models developed from field data for the same land types as those represented within the study area allowed for the extrapolation of overstorey and understorey cover, basal area and biomass values and these were modelled as trends over the latter half of the 20th century. These structural attributes have declined over the region because of land clearing with values for biomass changing from a mean of 58.0(+/-1.2)t/ha in 1953 to 41.1(+/-1.0)t/ha in 1991. The biomass of Acacia on clay and Eucalypt on texture contrast soils land types has declined most dramatically. Within uncleared vegetation there was an overall trend of increase from 56.1(+/-1.2)t/ha in 1951 to 67.6(+/-1.3)t/ha in 1995. The increase in structural attributes within uncleared vegetation was most pronounced for the Eucalypt on texture contrast soils and Eucalypt on clay land types. It was demonstrated that the sites sampled were representative of their land types and that spatial bias of the photography, undetected tree-killing, sampling error, inherent variability of structural attributes and measurement error should not have impacted greatly on bias or precision of trend estimates for well-sampled land types. Certainly the errors are not likely to be substantial for trends averaged over all land types and they provide an accurate assessment of the magnitude and direction of change. The technique presented here would appear to be a robust means of accounting for the above-ground woody component of woodlands and open forests and will also contribute to a broader understanding of savanna dynamics.

  17. Research of combination model for prediction of the trend of outbreak of hepatitis B

    Directory of Open Access Journals (Sweden)

    Yin-ping CHEN

    2014-03-01

    Full Text Available Objective To establish a combination model of autoregressive integrated moving average model and the grey dynamics (ARIMA-GM of hepatitis B incidence rate (1/100 000 to predict the trend of outbreak of hepatitis B, as to provide a scientific basis for the early discovery of the infectious diseases for the performance of countermeasures of controlling its spread. Methods The monthly incidence of hepatitis B in Qian'an city, Hebei province, was collected from Jan 2004 to Dec 2012, and a model (ARIMA was reproduced with SPSS software. The GM (1,1 model was used to correct the residual sequence with a threshold value, and a combined forecasting model was reproduced. This combination model was used to predict the monthly incidence rate in this city in 2013. Results The model ARIMA(0,1,1(0,1,112 was established successfully and the residual sequence was a white noise sequence. Then the GM (1,1 model with a threshold of 3 was used to correct its residuals and obtain its nonlinear feature extraction of information. The forecasting model met required precision standards (C=0.673, P=0.877, the fitting accuracy of which was basically qualified. The results showed that the MAE, MAPE of the ARIMA-GM combined model were smaller than that of a single model, and the combined model could improve the prediction accuracy. Using the combined model to forecast the incidence of hepatitis B during Jan 2013 to Dec 2013, the overall trend was relatively consistent with the condition of previous years. Conclusion The ARIMA-GM combined model can better fit the incidence rate of hepatitis B with a greater accuracy than the seasonal ARIMA model. The prediction results can provide the reference for the early warning system of HBV. DOI: 10.11855/j.issn.0577-7402.2014.01.12

  18. Managing Efficiency and Profitability Through Working Capital: an Empirical Analysis of BSE 200 Companies

    Directory of Open Access Journals (Sweden)

    Harsh Vineet Kaur

    2013-04-01

    Full Text Available Efficient management of working capital helps to avoid financial crises, thereby, increasing the profitability and enhances the firm value. The present study analyses the working capital performance of 164 manufacturing BSE 200 companies classified into 19 industries over the period of 2000-2010 based on working capital score calculated by using normalised values of Cash Conversion Efficiency, Days Operating Cycle and Days Working Capital. The study explores abundant scope to increase the efficiency of 145 companies by improving the parameters of analysis. The improvements are bound to generate increased profits and profitability of leading corporate of India. The study tests the relationship between the working capital score and profitability measured by Income to Current Assets and Income to Average Total Assets. The results of the study support earlier studies revealing that efficient management of working capital significantly affects profitability.

  19. Is it possible to measure diameters of metal nanoparticles using BSE imaging in FESEM?

    Science.gov (United States)

    Nebesarova, Jana; Langhans, Jan; Slouf, Miroslav; Pavlova, Ewa; Vancova, Marie

    2013-01-01

    The possibilities of using a field emission scanning electron microscope (FESEM) equipped with an Autrata improved yttrium aluminum garnet (YAG) detector of back-scattered electrons (BSE) for a determination of metal nanoparticles sizes were examined in this study. The diameters of Au and Pd nanoparticles with different sizes were resolved based on digitally recorded FESEM micrographs and were compared with diameters obtained with a transmission electron microscope (TEM). In the case of Au nanoparticles, the data obtained from the FESEM exhibited smaller values in comparison with data from the TEM. The Pd nanoparticles diameters measured in the FESEM were comparable with those determined by means of the TEM, however. The influence of various parameters like the sizes of nanoparticles, their composition, use of accelerating voltage and other working conditions in the FESEM on the measurement results are discussed.

  20. The Power (Law) of Indian Markets: Analysing NSE and BSE trading statistics

    CERN Document Server

    Sinha, S; Sinha, Sitabhra; Pan, Raj Kumar

    2006-01-01

    The nature of fluctuations in the Indian financial market is analyzed in this paper. We have looked at the price returns of individual stocks, with tick-by-tick data from the National Stock Exchange (NSE) and daily closing price data from both NSE and the Bombay Stock Exchange (BSE), the two largest exchanges in India. We find that the price returns in Indian markets follow a fat-tailed cumulative distribution, consistent with a power law having exponent $\\alpha \\sim 3$, similar to that observed in developed markets. However, the distributions of trading volume and the number of trades have a different nature than that seen in the New York Stock Exchange (NYSE). Further, the price movement of different stocks are highly correlated in Indian markets.

  1. The Power (Law) of Indian Markets: Analysing NSE and BSE Trading Statistics

    Science.gov (United States)

    Sinha, Sitabhra; Pan, Raj Kumar

    The nature of fluctuations in the Indian financial market is analyzed in this paper. We have looked at the price returns of individual stocks, with tick-by-tick data from the National Stock Exchange (NSE) and daily closing price data from both NSE and the Bombay Stock Exchange (BSE), the two largest exchanges in India. We find that the price returns in Indian markets follow a fat-tailed cumulative distribution, consistent with a power law having exponent α ˜ 3, similar to that observed in developed markets. However, the distributions of trading volume and the number of trades have a different nature than that seen in the New York Stock Exchange (NYSE). Further, the price movement of different stocks are highly correlated in Indian markets.

  2. Extensive ab initio study of the electronic states of BSe radical including spin-orbit coupling

    Science.gov (United States)

    Liu, Siyuan; Zhai, Hongsheng; Liu, Yufang

    2016-06-01

    The internally contracted multi-reference configuration interaction method (MRCI) with Davidson modification and the Douglas-Kroll scalar relativistic correction has been used to calculate the BSe molecule at the level of aug-cc-pV5Z basis set. The calculated electronic states, including 9 doublet and 6 quartet Λ-S states, are correlated to the dissociation limit of B(2Pu) + Se(3Pg) and B(2Pu) + Se(1Dg). The Spin-orbit coupling (SOC) interaction is taken into account via the state interaction approach with the full Breit-Pauli Hamiltonian operator, which causes the entire 15 Λ-S states to split into 32 Ω states. This is the first time that the spin-orbit coupling calculation has been carried out on BSe. The potential energy curves of the Λ-S and Ω electronic states are depicted with the aid of the avoided crossing rule between electronic states of the same symmetry. The spectroscopic constants of the bound Λ-S and Ω states were determined, which are in good agreement with the experimental data. The transition dipole moments (TDMs) and the Franck-Condon factors (FCs) of the transitions from the low-lying bound Ω states A2Π(I)3/2, B2Π(I)1/2 and C2Δ(I)3/2 to the ground state X2Σ+1/2 have also been presented. Based on the previous calculations, the radiative lifetimes of the A2Π(I)3/2, B2Π(I)1/2 and C2Δ(I)3/2 were evaluated.

  3. Site-occupancy distribution modeling to correct population-trend estimates derived from opportunistic observations

    Science.gov (United States)

    Kery, M.; Royle, J. Andrew; Schmid, Hans; Schaub, M.; Volet, B.; Hafliger, G.; Zbinden, N.

    2010-01-01

    Species' assessments must frequently be derived from opportunistic observations made by volunteers (i.e., citizen scientists). Interpretation of the resulting data to estimate population trends is plagued with problems, including teasing apart genuine population trends from variations in observation effort. We devised a way to correct for annual variation in effort when estimating trends in occupancy (species distribution) from faunal or floral databases of opportunistic observations. First, for all surveyed sites, detection histories (i.e., strings of detection-nondetection records) are generated. Within-season replicate surveys provide information on the detectability of an occupied site. Detectability directly represents observation effort; hence, estimating detectablity means correcting for observation effort. Second, site-occupancy models are applied directly to the detection-history data set (i.e., without aggregation by site and year) to estimate detectability and species distribution (occupancy, i.e., the true proportion of sites where a species occurs). Site-occupancy models also provide unbiased estimators of components of distributional change (i.e., colonization and extinction rates). We illustrate our method with data from a large citizen-science project in Switzerland in which field ornithologists record opportunistic observations. We analyzed data collected on four species: the widespread Kingfisher (Alcedo atthis. ) and Sparrowhawk (Accipiter nisus. ) and the scarce Rock Thrush (Monticola saxatilis. ) and Wallcreeper (Tichodroma muraria. ). Our method requires that all observed species are recorded. Detectability was biodiversity monitoring and modeling of species distributions. ?? 2010 Society for Conservation Biology.

  4. Spatial heterogeneity of the risk of BSE in France following the ban of meat and bone meal in cattle feed.

    Science.gov (United States)

    Abrial, David; Calavas, Didier; Jarrige, Nathalie; Ducrot, Christian

    2005-01-01

    In France, meat-and-bone meal (MBM) has been prohibited for cattle feeding since 1990, but bovine spongiform encephalopathy (BSE) cases, called 'NAIF', appeared in animals born after this feed ban. Furthermore, in 1996 a new measure was taken: removal of cadavers and specified risk materials (SRM) from the processing of MBM dedicated to animal feed. Nevertheless, BSE cases (called 'super-NAIF') appeared in cattle born after this measure was in force. We analysed the spatial distribution of 445 'NAIF' and 58 'super-NAIF' cases detected in France from July 1, 2001 to July 31, 2003. The detection of BSE was based both on the mandatory reporting system (MRS) and the systematic test screening of cattle at the abattoir and at the fallen-animal plant with rapid tests. The background population was based on the adult-cow census. The disease mapping of the BSE risk was based on the standardised incidence ratio (stochastic Poisson process). A spatial component, which takes into account the spatial dependence between the geographical units by a notion of adjacency was used to eliminate the over-dispersion in the risk assessment. The geographical units were defined by hexagons with a side of 23km (France had 1264 hexagons). The parameters were estimated by a Metropolis Gibbs sampling algorithm using the Markov-chain Monte Carlo methods. The BSE cases were not randomly distributed. Furthermore, the areas at risk for the 'super-NAIF' matched part of the areas at risk for the 'NAIF' cases-which suggests that it might be a common source of contamination.

  5. Trend-Residual Dual Modeling for Detection of Outliers in Low-Cost GPS Trajectories.

    Science.gov (United States)

    Chen, Xiaojian; Cui, Tingting; Fu, Jianhong; Peng, Jianwei; Shan, Jie

    2016-12-01

    Low-cost GPS (receiver) has become a ubiquitous and integral part of our daily life. Despite noticeable advantages such as being cheap, small, light, and easy to use, its limited positioning accuracy devalues and hampers its wide applications for reliable mapping and analysis. Two conventional techniques to remove outliers in a GPS trajectory are thresholding and Kalman-based methods, which are difficult in selecting appropriate thresholds and modeling the trajectories. Moreover, they are insensitive to medium and small outliers, especially for low-sample-rate trajectories. This paper proposes a model-based GPS trajectory cleaner. Rather than examining speed and acceleration or assuming a pre-determined trajectory model, we first use cubic smooth spline to adaptively model the trend of the trajectory. The residuals, i.e., the differences between the trend and GPS measurements, are then further modeled by time series method. Outliers are detected by scoring the residuals at every GPS trajectory point. Comparing to the conventional procedures, the trend-residual dual modeling approach has the following features: (a) it is able to model trajectories and detect outliers adaptively; (b) only one critical value for outlier scores needs to be set; (c) it is able to robustly detect unapparent outliers; and (d) it is effective in cleaning outliers for GPS trajectories with low sample rates. Tests are carried out on three real-world GPS trajectories datasets. The evaluation demonstrates an average of 9.27 times better performance in outlier detection for GPS trajectories than thresholding and Kalman-based techniques.

  6. Trend-Residual Dual Modeling for Detection of Outliers in Low-Cost GPS Trajectories

    Directory of Open Access Journals (Sweden)

    Xiaojian Chen

    2016-12-01

    Full Text Available Low-cost GPS (receiver has become a ubiquitous and integral part of our daily life. Despite noticeable advantages such as being cheap, small, light, and easy to use, its limited positioning accuracy devalues and hampers its wide applications for reliable mapping and analysis. Two conventional techniques to remove outliers in a GPS trajectory are thresholding and Kalman-based methods, which are difficult in selecting appropriate thresholds and modeling the trajectories. Moreover, they are insensitive to medium and small outliers, especially for low-sample-rate trajectories. This paper proposes a model-based GPS trajectory cleaner. Rather than examining speed and acceleration or assuming a pre-determined trajectory model, we first use cubic smooth spline to adaptively model the trend of the trajectory. The residuals, i.e., the differences between the trend and GPS measurements, are then further modeled by time series method. Outliers are detected by scoring the residuals at every GPS trajectory point. Comparing to the conventional procedures, the trend-residual dual modeling approach has the following features: (a it is able to model trajectories and detect outliers adaptively; (b only one critical value for outlier scores needs to be set; (c it is able to robustly detect unapparent outliers; and (d it is effective in cleaning outliers for GPS trajectories with low sample rates. Tests are carried out on three real-world GPS trajectories datasets. The evaluation demonstrates an average of 9.27 times better performance in outlier detection for GPS trajectories than thresholding and Kalman-based techniques.

  7. Trends of Summer Air Temperatures in the Romanian Carpathians Detected by Using a Serially Correlated Errors Model

    Directory of Open Access Journals (Sweden)

    Adina-Eliza CROITORU

    2014-11-01

    Full Text Available This paper investigates summer temperature trends in the Romanian Carpathian Mountains, for three types of topographies: summit, slope and depression. We used a change-point regression model with serially correlated errors and compared it with a mainstream change-point model with independent errors. Statistical theory ensures that the former model gives a more accurate trend analysis than the latter model. For both models we identified strongly decreasing trends before the change-point and strongly increasing trends afterwards for most summer temperature series. The change-points are more consistent with each other, in the early 80’s, when using the former model. These general results occur for all topography types. A separate multiple regression model reveals that the temperature dynamics in the Romanian Carpathians can be explained by a linear effect of several major atmospheric circulation patterns

  8. Trends and Challenges of Electronic Auctions as a New Business Model

    Directory of Open Access Journals (Sweden)

    Margarita Janeska

    2014-11-01

    Full Text Available The virtual internet based market allowed different forms of trading. Electronic business opens up new markets and market segments. Auctions are a very reliable and competitive trading model which allows to achieve fair prices and to choose the optimal business partners. The purpose of this model is that the system can extend the duration of the auction until they met various commercial applications.The basic motivation for research in this paper is the increasing trend of the use of electronic auctions in the process of selling and buying products and services.

  9. Prognosticating fault development rate in wind turbine generator bearings using local trend models

    DEFF Research Database (Denmark)

    Skrimpas, Georgios Alexandros; Palou, Jonel; Sweeney, Christian Walsted;

    2016-01-01

    Generator bearing defects, e.g. ball, inner and outer race defects, are ranked among the most frequent mechanical failures encountered in wind turbines. Diagnosis and prognosis of bearing faults can be successfully implemented using vibration based condition monitoring systems, where tracking...... the signal energy between 10Hz to 1000Hz is utilized as feature to characterize the severity of developing bearing faults. Furthermore, local trend models are employed to predict the progression of bearing defects from a vibration standpoint in accordance with the limits suggested in ISO 10816. Predictions...... of vibration trends from multi-megawatt wind turbine generators are presented, showing the effectiveness of the suggested approach on the calculation of the RUL and fault progression rate....

  10. State-space modeling of population sizes and trends in Nihoa Finch and Millerbird

    Science.gov (United States)

    Gorresen, P. Marcos; Brinck, Kevin W.; Camp, Richard J.; Farmer, Chris; Plentovich, Sheldon M.; Banko, Paul C.

    2016-01-01

    Both of the 2 passerines endemic to Nihoa Island, Hawai‘i, USA—the Nihoa Millerbird (Acrocephalus familiaris kingi) and Nihoa Finch (Telespiza ultima)—are listed as endangered by federal and state agencies. Their abundances have been estimated by irregularly implemented fixed-width strip-transect sampling from 1967 to 2012, from which area-based extrapolation of the raw counts produced highly variable abundance estimates for both species. To evaluate an alternative survey method and improve abundance estimates, we conducted variable-distance point-transect sampling between 2010 and 2014. We compared our results to those obtained from strip-transect samples. In addition, we applied state-space models to derive improved estimates of population size and trends from the legacy time series of strip-transect counts. Both species were fairly evenly distributed across Nihoa and occurred in all or nearly all available habitat. Population trends for Nihoa Millerbird were inconclusive because of high within-year variance. Trends for Nihoa Finch were positive, particularly since the early 1990s. Distance-based analysis of point-transect counts produced mean estimates of abundance similar to those from strip-transects but was generally more precise. However, both survey methods produced biologically unrealistic variability between years. State-space modeling of the long-term time series of abundances obtained from strip-transect counts effectively reduced uncertainty in both within- and between-year estimates of population size, and allowed short-term changes in abundance trajectories to be smoothed into a long-term trend.

  11. Applied Mathematical Problem Solving, Modelling, Applications, and Links to Other Subjects--State, Trends and Issues in Mathematics Instruction.

    Science.gov (United States)

    Blum, Werner; Niss, Mogens

    1991-01-01

    This paper reviews the present state, recent trends, and prospective lines of development concerning applied problem solving, modeling, and their respective applications. Four major trends are scrutinized with respect to curriculum inclusion: a widened spectrum of arguments, an increased universality, an increased consolidation, and an extended…

  12. Simulated discharge trends indicate robustness of hydrological models in a changing climate

    Science.gov (United States)

    Addor, Nans; Nikolova, Silviya; Seibert, Jan

    2016-04-01

    Assessing the robustness of hydrological models under contrasted climatic conditions should be part any hydrological model evaluation. Robust models are particularly important for climate impact studies, as models performing well under current conditions are not necessarily capable of correctly simulating hydrological perturbations caused by climate change. A pressing issue is the usually assumed stationarity of parameter values over time. Modeling experiments using conceptual hydrological models revealed that assuming transposability of parameters values in changing climatic conditions can lead to significant biases in discharge simulations. This raises the question whether parameter values should to be modified over time to reflect changes in hydrological processes induced by climate change. Such a question denotes a focus on the contribution of internal processes (i.e., catchment processes) to discharge generation. Here we adopt a different perspective and explore the contribution of external forcing (i.e., changes in precipitation and temperature) to changes in discharge. We argue that in a robust hydrological model, discharge variability should be induced by changes in the boundary conditions, and not by changes in parameter values. In this study, we explore how well the conceptual hydrological model HBV captures transient changes in hydrological signatures over the period 1970-2009. Our analysis focuses on research catchments in Switzerland undisturbed by human activities. The precipitation and temperature forcing are extracted from recently released 2km gridded data sets. We use a genetic algorithm to calibrate HBV for the whole 40-year period and for the eight successive 5-year periods to assess eventual trends in parameter values. Model calibration is run multiple times to account for parameter uncertainty. We find that in alpine catchments showing a significant increase of winter discharge, this trend can be captured reasonably well with constant

  13. Modelling impacts of temperature, and acidifying and eutrophying deposition on DOC trends

    Science.gov (United States)

    Sawicka, Kasia; Rowe, Ed; Evans, Chris; Monteith, Don; Vanguelova, Elena; Wade, Andrew; Clark, Joanna

    2017-04-01

    Surface water dissolved organic carbon (DOC) concentrations in large parts of the northern hemisphere have risen over the past three decades, raising concern about enhanced contributions of carbon to the atmosphere and seas and oceans. The effect of declining acid deposition has been identified as a key control on DOC trends in soil and surface waters, since pH and ionic strength affect sorption and desorption of DOC. However, since DOC is derived mainly from recently-fixed carbon, and organic matter decomposition rates are considered sensitive to temperature, uncertainty persists regarding the extent to the relative importance of different drivers that affect these upward trends. We ran the dynamic model MADOC (Model of Acidity and Soil Organic Carbon) for a range of UK soils (podzols, gleysols and peatland), for which the time-series were available, to consider the likely relative importance of decreased deposition of sulphate and chloride, accumulation of reactive N, and higher temperatures, on DOC production in different soils. Modelled patterns of DOC change generally agreed favourably with measurements collated over 10-20 years, but differed markedly between sites. While the acidifying effect of sulphur deposition appeared to be the predominant control on the observed soil water DOC trends in all the soils considered other than a blanket peat, the model suggested that over the long term, the effects of nitrogen deposition on N-limited soils may have been sufficient to elevate the DOC recovery trajectory significantly. The second most influential cause of rising DOC in the model simulations was N deposition in ecosystems that are N-limited and respond with stimulated plant growth. Although non-marine chloride deposition made some contribution to acidification and recovery, it was not amongst the main drivers of DOC change. Warming had almost no effect on modelled historic DOC trends, but may prove to be a significant driver of DOC in future via its influence

  14. Modeling Growth Trend and Forecasting Techniques for Vehicular Population in India

    Directory of Open Access Journals (Sweden)

    Kartikeya Jha

    2013-06-01

    Full Text Available Forecasting and estimation of growth in vehicular population is a sine qua non of any major transportation engineering development, requires capturing the past trend and using it to predict the future trend based on qualified assumptions, simulations and models created using explanatory variables. This work attempts to review the in vogue approaches and investigate a more contemporary approach, the Time Series (TS Analysis. Three fundamentally different methods were explored and results from each of these analyses were collated to check for respective levels of accuracy in predicting vehicular population for the same target year. Within the scope of this study and estimation, results obtained from TS Analysis were found to be considerably more accurate than those from Trend Line Analysis and observably better than those from Econometric Analysis. To reinforce these observations and inferences drawn, a second set of analysis was done on more recent input by using AADT data from PeMS, California. Inter alia this was carried out to contrast any statistical improvement observed when doing TS analysis with rich and accurate data. With all the data sets used and locations analyzed for forecasting, the Time Series analysis technique was invariably found to be a potent tool for forecasting.

  15. Geospatial Modeling for Investigating Spatial Pattern and Change Trend of Temperature and Rainfall

    Directory of Open Access Journals (Sweden)

    Md. Abu Syed

    2016-04-01

    Full Text Available Bangladesh has been experiencing increased temperature and change in precipitation regime, which might adversely affect the important ecosystems in the country differentially. The river flows and groundwater recharge over space and time are determined by changes in temperature, evaporation and crucially precipitation. These again have a spatio-temporal dimension. This geospatial modeling research aimed at investigating spatial patterns and changing trends of temperature and rainfall within the geographical boundary of Bangladesh. This would facilitate better understanding the change pattern and their probable impacts on the ecosystem. The southeastern region, which is one of the most important forest ecosystem zones in the country, is experiencing early onset and withdrawal of rain but increasing trends in total rainfall except in the Monsoon season. This means that the region is experiencing a lower number of rainy days. However, total rainfall has not changed significantly. The differential between maximum and minimum showed an increasing trend. This changing pattern in average max and min temperature along with precipitation might cause a situation in which the species that are growing now may shift to suitable habitats elsewhere in the future. Consequently, the biodiversity, watersheds and fisheries, productivity of land, agriculture and food security in the region will be affected by these observed changes in climate.

  16. Structural Uncertainty in Model-Simulated Trends of Global Gross Primary Production

    Directory of Open Access Journals (Sweden)

    Zaichun Zhu

    2013-03-01

    Full Text Available Projected changes in the frequency and severity of droughts as a result of increase in greenhouse gases have a significant impact on the role of vegetation in regulating the global carbon cycle. Drought effect on vegetation Gross Primary Production (GPP is usually modeled as a function of Vapor Pressure Deficit (VPD and/or soil moisture. Climate projections suggest a strong likelihood of increasing trend in VPD, while regional changes in precipitation are less certain. This difference in projections between VPD and precipitation can cause considerable discrepancies in the predictions of vegetation behavior depending on how ecosystem models represent the drought effect. In this study, we scrutinized the model responses to drought using the 30-year record of Global Inventory Modeling and Mapping Studies (GIMMS 3g Normalized Difference Vegetation Index (NDVI dataset. A diagnostic ecosystem model, Terrestrial Observation and Prediction System (TOPS, was used to estimate global GPP from 1982 to 2009 under nine different experimental simulations. The control run of global GPP increased until 2000, but stayed constant after 2000. Among the simulations with single climate constraint (temperature, VPD, rainfall and solar radiation, only the VPD-driven simulation showed a decrease in 2000s, while the other scenarios simulated an increase in GPP. The diverging responses in 2000s can be attributed to the difference in the representation of the impact of water stress on vegetation in models, i.e., using VPD and/or precipitation. Spatial map of trend in simulated GPP using GIMMS 3g data is consistent with the GPP driven by soil moisture than the GPP driven by VPD, confirming the need for a soil moisture constraint in modeling global GPP.

  17. Use of hierarchical models to analyze European trends in congenital anomaly prevalence.

    Science.gov (United States)

    Cavadino, Alana; Prieto-Merino, David; Addor, Marie-Claude; Arriola, Larraitz; Bianchi, Fabrizio; Draper, Elizabeth; Garne, Ester; Greenlees, Ruth; Haeusler, Martin; Khoshnood, Babak; Kurinczuk, Jenny; McDonnell, Bob; Nelen, Vera; O'Mahony, Mary; Randrianaivo, Hanitra; Rankin, Judith; Rissmann, Anke; Tucker, David; Verellen-Dumoulin, Christine; de Walle, Hermien; Wellesley, Diana; Morris, Joan K

    2016-06-01

    Surveillance of congenital anomalies is important to identify potential teratogens. Despite known associations between different anomalies, current surveillance methods examine trends within each subgroup separately. We aimed to evaluate whether hierarchical statistical methods that combine information from several subgroups simultaneously would enhance current surveillance methods using data collected by EUROCAT, a European network of population-based congenital anomaly registries. Ten-year trends (2003 to 2012) in 18 EUROCAT registries over 11 countries were analyzed for the following groups of anomalies: neural tube defects, congenital heart defects, digestive system, and chromosomal anomalies. Hierarchical Poisson regression models that combined related subgroups together according to EUROCAT's hierarchy of subgroup coding were applied. Results from hierarchical models were compared with those from Poisson models that consider each congenital anomaly separately. Hierarchical models gave similar results as those obtained when considering each anomaly subgroup in a separate analysis. Hierarchical models that included only around three subgroups showed poor convergence and were generally found to be over-parameterized. Larger sets of anomaly subgroups were found to be too heterogeneous to group together in this way. There were no substantial differences between independent analyses of each subgroup and hierarchical models when using the EUROCAT anomaly subgroups. Considering each anomaly separately, therefore, remains an appropriate method for the detection of potential changes in prevalence by surveillance systems. Hierarchical models do, however, remain an interesting alternative method of analysis when considering the risks of specific exposures in relation to the prevalence of congenital anomalies, which could be investigated in other studies. Birth Defects Research (Part A) 106:480-10, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  18. Control methods for cattle feedstuffs aimed at prevention of Bovine spongiform encephalopathy (BSE

    Directory of Open Access Journals (Sweden)

    Nešić Ksenija

    2006-01-01

    Full Text Available In the course of the last decades of the twentieth century, more than 30 new diseases were determined for the first time in history. Bovine spongiform encephalopathy (BSE, or "mad cow disease" is one of them. The disease implies the subacute neurodegenerative transmission of spongiform encephalopathy and it was diagnosed and described for the first time in Great Britain in 1986. A theory has been established that BSE is spread through feedstuffs, more precisely, meat-bone flour which contains infective proteins of ruminants, and legislature has been passed throughout the world with the objective of preventing the entry of meat-bone flour into the food chain. The complete ban of the use of meat-bone flour for all farm animals (with the exception of fish flour for non-ruminants and an adequate thermal treatment in the production of meat-bone flour (133ºC, 3 bar, 20 min are the elements on which the European Union (EU legislature is based. The regulations in our country include a ban on the use of meat-bone flour in cattle feedstuffs and a ban on imports of beef proteins. The implementation of this legislature throughout the world requires the corresponding analytical means. At the present time, there are several available possibilities: optic microscopy, PCR, immunoprobes, spectroscopic methods, and several others which are still being examined for use for this purpose. All the analytical methods are being applied with the objective of controlling the implementation of the current regulations, but also in order to discover possible cross contamination that could take place in factories of animal feedstuffs, during transportation, storage, or on farms, in particular when there are no separate lines for feedstuffs that contains meat-bone flour and others in which even its traces are banned. In order to secure the successful control and prevention of bovine spongiform encephalopathy in our country, as well as to secure the unhindered continuation of

  19. Trends and biases in global scientific literature about ecological niche models.

    Science.gov (United States)

    Vaz, U L; Cunha, H F; Nabout, J C

    2015-11-01

    Recently, ecological niche models have been employed to investigate the potential geographical distribution of species. However, it is necessary to analyze the vast number of publications on this topic to understand the trends and biases of research using ecological niche models (ENMs). Therefore, this study aims to investigate trends in the scientific literature regarding studies on ENMs. For the quantitative analysis of the literature on ENMs, we performed a search in the Thomson ISI (Web of Science) database between 1991 and 2013. The search identified 3042 papers containing preselected keywords in either the title or abstract. The results showed that the number of papers has increased over the years (r=0.77, Pplants (402 papers, or 28.36% of the total). There was no relationship between the modeling method used and the taxonomic group studied (χ2=4.8, P=0.15). Finally, the wide availability of biological, environmental and computational resources has elicited the broad use of tools for ENMs. Despite the conceptual discussions of the ENMs, this method is currently the most effective way to evaluate the potential geographical distribution of species, and to predict the distribution under different environmental conditions (i.e., future or past scenarios).

  20. Evolution History and Development Trend of Industrialized Live Pig Breeding Model in China

    Institute of Scientific and Technical Information of China (English)

    Zhongming; SHEN

    2013-01-01

    Tremendous achievements of live pig industry in China are closely related to the industrialization of the industry,and development trend of the latter is essential for maintaining sustained and stable development of animal husbandry.The paper,on the basis of defining the evolution of industrialized live pig breeding model,elaborated the industrialized operation models of live pig industry in China since 1978,i.e.household operation,large-scale operation,and industrialized operation.The external environment for the development of live pig industry was analyzed,such as global economic competition,development of experience economy,and stronger green consciousness of consumers.Then development trend of industrialized live pig breeding was analyzed as"expanding international market,consolidating domestic market,integrating resources of live pig industry for the integrated operation,promoting the industrialization model and breeding technology driven by live pig processing,applying animal welfare and the internet of things in live pig breeding industry".

  1. Sea ice leads in the Arctic Ocean: Model assessment, interannual variability and trends

    Science.gov (United States)

    Wang, Q.; Danilov, S.; Jung, T.; Kaleschke, L.; Wernecke, A.

    2016-07-01

    Sea ice leads in the Arctic are important features that give rise to strong localized atmospheric heating; they provide the opportunity for vigorous biological primary production, and predicting leads may be of relevance for Arctic shipping. It is commonly believed that traditional sea ice models that employ elastic-viscous-plastic (EVP) rheologies are not capable of properly simulating sea ice deformation, including lead formation, and thus, new formulations for sea ice rheologies have been suggested. Here we show that classical sea ice models have skill in simulating the spatial and temporal variation of lead area fraction in the Arctic when horizontal resolution is increased (here 4.5 km in the Arctic) and when numerical convergence in sea ice solvers is considered, which is frequently neglected. The model results are consistent with satellite remote sensing data and discussed in terms of variability and trends of Arctic sea ice leads. It is found, for example, that wintertime lead area fraction during the last three decades has not undergone significant trends.

  2. Assessing the status and trend of bat populations across broad geographic regions with dynamic distribution models

    Science.gov (United States)

    Rodhouse, Thomas J.; Ormsbee, Patricia C.; Irvine, Kathryn M.; Vierling, Lee A.; Szewczak, Joseph M.; Vierling, Kerri T.

    2012-01-01

    Bats face unprecedented threats from habitat loss, climate change, disease, and wind power development, and populations of many species are in decline. A better ability to quantify bat population status and trend is urgently needed in order to develop effective conservation strategies. We used a Bayesian autoregressive approach to develop dynamic distribution models for Myotis lucifugus, the little brown bat, across a large portion of northwestern USA, using a four-year detection history matrix obtained from a regional monitoring program. This widespread and abundant species has experienced precipitous local population declines in northeastern USA resulting from the novel disease white-nose syndrome, and is facing likely range-wide declines. Our models were temporally dynamic and accounted for imperfect detection. Drawing on species–energy theory, we included measures of net primary productivity (NPP) and forest cover in models, predicting that M. lucifugus occurrence probabilities would covary positively along those gradients.

  3. 21st Century Trends in Antarctic Temperature and Polar Stratospheric Cloud (PSC) Area in the GEOS Chemistry-Climate Model

    Science.gov (United States)

    Hurwitz, M. M.; Newman, P. A.

    2010-01-01

    This study examines trends in Antarctic temperature and APSC, a temperature proxy for the area of polar stratospheric clouds, in an ensemble of Goddard Earth Observing System (GEOS) chemistry-climate model (CCM) simulations of the 21st century. A selection of greenhouse gas, ozone-depleting substance, and sea surface temperature scenarios is used to test the trend sensitivity to these parameters. One scenario is used to compare temperature trends in two versions of the GEOS CCM. An extended austral winter season is examined in detail. In May, June, and July, the expected future increase in CO2-related radiative cooling drives temperature trends in the Antarctic lower stratosphere. At 50 hPa, a 1.3 K cooling is expected between 2000 and 2100. Ozone levels increase, despite this robust cooling signal and the consequent increase in APSC, suggesting the enhancement of stratospheric transport in future. In the lower stratosphere, the choice of climate change scenarios does not affect the magnitude of the early winter cooling. Midwinter temperature trends are generally small. In October, APSC trends have the same sign as the prescribed halogen trends. That is, there are negative APSC trends in "grealistic future" simulations, where halogen loading decreases in accordance with the Montreal Protocol and CO2 continues to increase. In these simulations, the speed of ozone recovery is not influenced by either the choice of sea surface temperature and greenhouse gas scenarios or by the model version.

  4. Clinical signs, histopathology and genetics of experimental transmission of BSE and natural scrapie to sheep and goats.

    Science.gov (United States)

    Foster, J D; Parnham, D; Chong, A; Goldmann, W; Hunter, N

    2001-02-10

    This paper compares the dinical signs, histopathology, detection of PrPSc protein and PrP genetics of the transmission of BSE to sheep and goats, with the effects of the transmission of natural scrapie from a brain homogenate from a single sheep. After intracerebral and oral inoculations there were similarities in the clinical signs due to the two sources of infection, but there were differences in pathology at the end stage of disease and in the genotypes of the sheep which succumbed to the challenges. The incubation period of BSE was associated with the sheep PrP codon 171 genotype, but the natural scrapie source, despite inducing disease only in known susceptible genotypes, showed no clear association with PrP genotype.

  5. Modeling flight attendants' exposure to secondhand smoke in commercial aircraft: historical trends from 1955 to 1989.

    Science.gov (United States)

    Liu, Ruiling; Dix-Cooper, Linda; Hammond, S Katharine

    2015-01-01

    Flight attendants were exposed to elevated levels of secondhand smoke (SHS) in commercial aircraft when smoking was allowed on planes. During flight attendants' working years, their occupational SHS exposure was influenced by various factors, including the prevalence of active smokers on planes, fliers' smoking behaviors, airplane flight load factors, and ventilation systems. These factors have likely changed over the past six decades and would affect SHS concentrations in commercial aircraft. However, changes in flight attendants' exposure to SHS have not been examined in the literature. This study estimates the magnitude of the changes and the historic trends of flight attendants' SHS exposure in U.S. domestic commercial aircraft by integrating historical changes of contributing factors. Mass balance models were developed and evaluated to estimate flight attendants' exposure to SHS in passenger cabins, as indicated by two commonly used tracers (airborne nicotine and particulate matter (PM)). Monte Carlo simulations integrating historical trends and distributions of influence factors were used to simulate 10,000 flight attendants' exposure to SHS on commercial flights from 1955 to 1989. These models indicate that annual mean SHS PM concentrations to which flight attendants were exposed in passenger cabins steadily decreased from approximately 265 μg/m(3) in 1955 and 1960 to 93 μg/m(3) by 1989, and airborne nicotine exposure among flight attendants also decreased from 11.1 μg/m(3) in 1955 to 6.5 μg/m(3) in 1989. Using duration of employment as an indicator of flight attendants' cumulative occupational exposure to SHS in epidemiological studies would inaccurately assess their lifetime exposures and thus bias the relationship between the exposure and health effects. This historical trend should be considered in future epidemiological studies.

  6. 北方地区牛海绵状脑病(BSE)检测工作报告

    Institute of Scientific and Technical Information of China (English)

    赵德明; 秦秀慧; 李军; 马李颖; 赵维宁; 黄伟忠

    2003-01-01

    @@ 随着全球经济一体化进程的加速,国际贸易和国际交往日趋频繁,动物海绵状脑病在全球扩散的危险性大大增加,病牛病(BSE)、羊痒病(Scrapie)等在世界范围内呈蔓围内呈蔓延的趋势.

  7. Frequencies of polymorphisms associated with BSE resistance differ significantly between Bos taurus, Bos indicus, and composite cattle

    Directory of Open Access Journals (Sweden)

    Seabury Christopher M

    2008-09-01

    Full Text Available Abstract Background Transmissible spongiform encephalopathies (TSEs are neurodegenerative diseases that affect several mammalian species. At least three factors related to the host prion protein are known to modulate susceptibility or resistance to a TSE: amino acid sequence, atypical number of octapeptide repeats, and expression level. These factors have been extensively studied in breeds of Bos taurus cattle in relation to classical bovine spongiform encephalopathy (BSE. However, little is currently known about these factors in Bos indicus purebred or B. indicus × B. taurus composite cattle. The goal of our study was to establish the frequency of markers associated with enhanced susceptibility or resistance to classical BSE in B. indicus purebred and composite cattle. Results No novel or TSE-associated PRNP-encoded amino acid polymorphisms were observed for B. indicus purebred and composite cattle, and all had the typical number of octapeptide repeats. However, differences were observed in the frequencies of the 23-bp and 12-bp insertion/deletion (indel polymorphisms associated with two bovine PRNP transcription regulatory sites. Compared to B. taurus, B. indicus purebred and composite cattle had a significantly lower frequency of 23-bp insertion alleles and homozygous genotypes. Conversely, B. indicus purebred cattle had a significantly higher frequency of 12-bp insertion alleles and homozygous genotypes in relation to both B. taurus and composite cattle. The origin of these disparities can be attributed to a significantly different haplotype structure within each species. Conclusion The frequencies of the 23-bp and 12-bp indels were significantly different between B. indicus and B. taurus cattle. No other known or potential risk factors were detected for the B. indicus purebred and composite cattle. To date, no consensus exists regarding which bovine PRNP indel region is more influential with respect to classical BSE. Should one particular

  8. THE EFFECT OF FOOD-SAFETY RELATED INFORMATION ON CONSUMER PREFERENCE: THE CASE OF THE BSE OUTBREAK IN JAPAN

    OpenAIRE

    Jin, Hyun Joung; Sun, Changyou; Koo, Won W.

    2003-01-01

    This paper uses a nonparametric approach for testing whether there is a structural change in the meat demand of Japanese consumers due to the BSE (mad-cow disease) outbreak in the country. The axiom of revealed preference is utilized to test the stability of preference in Japanese meat consumption. The matrix of weak form of revealed preference (WARP) is partitioned and Kruskal-Wallis statistics are derived to evaluate whether the switches of preference are transitory or due to a structural c...

  9. Exploring the recent trend in esophageal adenocarcinoma incidence and mortality using comparative simulation modeling.

    Science.gov (United States)

    Kong, Chung Yin; Kroep, Sonja; Curtius, Kit; Hazelton, William D; Jeon, Jihyoun; Meza, Rafael; Heberle, Curtis R; Miller, Melecia C; Choi, Sung Eun; Lansdorp-Vogelaar, Iris; van Ballegooijen, Marjolein; Feuer, Eric J; Inadomi, John M; Hur, Chin; Luebeck, E Georg

    2014-06-01

    The incidence of esophageal adenocarcinoma (EAC) has increased five-fold in the United States since 1975. The aim of our study was to estimate future U.S. EAC incidence and mortality and to shed light on the potential drivers in the disease process that are conduits for the dramatic increase in EAC incidence. A consortium of three research groups calibrated independent mathematical models to clinical and epidemiologic data including EAC incidence from the Surveillance, Epidemiology, and End Results (SEER 9) registry from 1975 to 2010. We then used a comparative modeling approach to project EAC incidence and mortality to year 2030. Importantly, all three models identified birth cohort trends affecting cancer progression as a major driver of the observed increases in EAC incidence and mortality. All models predict that incidence and mortality rates will continue to increase until 2030 but with a plateauing trend for recent male cohorts. The predicted ranges of incidence and mortality rates (cases per 100,000 person years) in 2030 are 8.4 to 10.1 and 5.4 to 7.4, respectively, for males, and 1.3 to 1.8 and 0.9 to 1.2 for females. Estimates of cumulative cause-specific EAC deaths between both sexes for years 2011 to 2030 range between 142,300 and 186,298, almost double the number of deaths in the past 20 years. Through comparative modeling, the projected increases in EAC cases and deaths represent a critical public health concern that warrants attention from cancer control planners to prepare potential interventions. Quantifying this burden of disease will aid health policy makers to plan appropriate cancer control measures. Cancer Epidemiol Biomarkers Prev; 23(6); 997-1006. ©2014 AACR. ©2014 American Association for Cancer Research.

  10. Modeling the status, trends, and impacts of wild bee abundance in the United States.

    Science.gov (United States)

    Koh, Insu; Lonsdorf, Eric V; Williams, Neal M; Brittain, Claire; Isaacs, Rufus; Gibbs, Jason; Ricketts, Taylor H

    2016-01-05

    Wild bees are highly valuable pollinators. Along with managed honey bees, they provide a critical ecosystem service by ensuring stable pollination to agriculture and wild plant communities. Increasing concern about the welfare of both wild and managed pollinators, however, has prompted recent calls for national evaluation and action. Here, for the first time to our knowledge, we assess the status and trends of wild bees and their potential impacts on pollination services across the coterminous United States. We use a spatial habitat model, national land-cover data, and carefully quantified expert knowledge to estimate wild bee abundance and associated uncertainty. Between 2008 and 2013, modeled bee abundance declined across 23% of US land area. This decline was generally associated with conversion of natural habitats to row crops. We identify 139 counties where low bee abundances correspond to large areas of pollinator-dependent crops. These areas of mismatch between supply (wild bee abundance) and demand (cultivated area) for pollination comprise 39% of the pollinator-dependent crop area in the United States. Further, we find that the crops most highly dependent on pollinators tend to experience more severe mismatches between declining supply and increasing demand. These trends, should they continue, may increase costs for US farmers and may even destabilize crop production over time. National assessments such as this can help focus both scientific and political efforts to understand and sustain wild bees. As new information becomes available, repeated assessments can update findings, revise priorities, and track progress toward sustainable management of our nation's pollinators.

  11. Health communication and consumer behavior on meat in Belgium: from BSE until dioxin.

    Science.gov (United States)

    Verbeke, W; Viaene, J; Guiot, O

    1999-01-01

    This article focuses on the impact of mass media meat-health information on consumer perception, attitude, and behavior toward fresh meat in Belgium. In a situation similar to that which occurred in most other European countries, Belgian fresh meat consumption fell considerably during 1995-1999. A multitude of messages linking meat consumption to human health risks were reported by mass media. Bovine Spongiform Encephalopathy (BSE) since 1996 and dioxin in 1999 constituted the major issues. Empirical research, conducted in April 1998, revealed the tremendous negative impact of mass media coverage of meat-health issues on consumer risk perception, health concern, and attitude and behavior toward fresh meat. Oppositely, personal communication through butchers had only a small effect on consumer decision-making in this era dominated by alarming meat-health press. Implications are threefold. First, mass media should be aware of its social responsibilities, which include spreading reliable and correct information to the society. This is especially the case as human health risks are involved. Second, the meat industry urgently needs to reorient itself toward quality, safety, and transparency. Finally, future communication dealing with similar crises situations requires cooperation across the meat chain, government, and those who are responsible for public health promotion and communication.

  12. Economic analysis of animal disease outbreaks--BSE and Bluetongue disease as examples.

    Science.gov (United States)

    Gethmann, Jörn; Probst, Carolina; Sauter-Louis, Carola; Conraths, Franz Josef

    2015-01-01

    Although there is a long tradition of research on animal disease control, economic evaluation of control measures is rather limited in veterinary medicine. This may, on the one hand, be due to the different types of costs and refunds and the different people and organizations bearing them, such as animal holders, county, region, state or European Union, but it may also be due to the fact that economic analyses are both complex and time consuming. Only recently attention has turned towards economic analysis in animal disease control. Examples include situations, when decisions between different control measures must be taken, especially if alternatives to culling or compulsory vaccination are under discussion. To determine an optimal combination of control measures (strategy), a cost-benefit analysis should be performed. It is not necessary to take decisions only based on the financial impact, but it becomes possible to take economic aspects into account. To this end, the costs caused by the animal disease and the adopted control measures must be assessed. This article presents a brief overview of the methodological approaches used to retrospectively analyse the economic impact of two particular relevant diseases in Germany in the last few years: Blue-tongue disease (BT) and Bovine Spongiform Encephalopathy (BSE).

  13. Modelling the decadal trend of ecosystem carbon fluxes demonstrates the important role of functional changes in a temperate deciduous forest

    DEFF Research Database (Denmark)

    Wu, Jian; Jansson, P.E.; van der Linden, Leon;

    2013-01-01

    Temperate forests are globally important carbon sinks and stocks. Trends in net ecosystem exchange have been observed in a Danish beech forest and this trend cannot be entirely attributed to changing climatic drivers. This study sought to clarify the mechanisms responsible for the observed trend......, the latent and sensible heat fluxes and the CO2 fluxes decreased the parameter uncertainty considerably compared to using CO2 fluxes as validation data alone. The fitted model was able to simulate the observed carbon fluxes well (R2=0.8, mean error=0.1gCm−2d−1) but did not reproduce the decadal (1997......–2009) trend in carbon uptake when global parameter estimates were used. Annual parameter estimates were able to reproduce the decadal scale trend; the yearly fitted posterior parameters (e.g. the light use efficiency) indicated a role for changes in the ecosystem functional properties. A possible role...

  14. A Trend Analysis of Competition Positioning in Chinese Seaports by Using DEA Model and BCG Matrix

    Institute of Scientific and Technical Information of China (English)

    Hoki Nam

    2007-01-01

    <正>This paper has shown the trend of competition positioning of ten critical Chinese seaports from 2003 to 2006 by using DEA model for the performance efficiency analysis and BCG matrix,which consists of relative market share and growth rate as well as the scores of both BCC and CCR in the vertical and horizontal axis of BCG matrix.The expected results will include the total economic efficiency ranking of each Chinese seaport,and the relative competitive positioning in terms of growth rate and efficiency scores.The main policy implication of this paper is to emphasize the DEA model and BCG matrix method can support the seaport managers the basic information for planning the future port management for enhancing the competitive positioning among Chinese seaports.

  15. Trends In Modelling Neutral-Atmospheric Electromagnetic Delays in a 'Big Data' World

    Science.gov (United States)

    Santos, M. C.; Nikolaidou, T.

    2015-12-01

    Modelling the delay suffered by electromagnetic waves while they cross the neutral-atmosphere is of fundamental importance for several applications that help enhancing our understanding of the Earth system. Initially, this modelling was based on climatological models derived from sparse data sets. An improvement in models followed as more observing techniques became available, and denser networks started to be developed. Somehow in parallel, and more recently, investigation efforts started to be concentrated on the use of numerical weather prediction (NWP) models, from where neutral-atmospheric delay parameters can derived through ray-tracing. There are a few limitations in both approaches. Models based on climatology are based on sparse data covering a certain period of time, whereas NWP models although based on more realistic data, are provided on intervals that range several hours. A third way is about to be engaged, and it can be seen as a natural development due to an increase in the number of sensors and an enhancement of their geographical distribution, generating a continuous flow of data, being them both satellite-based and ground-based. The question that is posed ahead of us is on how to make use of these huge data sets, which will provide the best possible representation of the neutral-atmosphere at any given time, as readily and as accurately as possible. This situation fits well within what today is known as big data. This paper will explore and discuss scenarios that have potential to open new trends in modeling the neutral-atmospheric delay. They include near real-time empirical model updates, sequential improvement of Marini mapping function coefficients (e.g., within a VMF) and a self-feeding. The discussion and simulations that will be shown cover the whole planet. The pros and cons of each approach will be discussed in comparison with what is done today. Simulations show potential improvement of up to 25% under certain circumstances.

  16. Trends in Mesospheric Dynamics and Chemistry: Simulations With a Model of the Entire Atmosphere

    Science.gov (United States)

    Brasseur, G. P.

    2005-05-01

    The cooling resulting from infrared CO2 radiative transfer is a major contribution to the energy budget of the middle atmosphere and thermosphere. The rapid increase of the atmospheric CO2 concentration resulting from anthropogenic emissions is therefore expected to lead, in general, to a substantial cooling in this height range. This can potentially be counteracted by heating due to absorption of near infrared radiation by CO2. Changes in ozone as a consequence of increasing methane and water vapor may also have an impact on the energy budget as dynamical changes caused by increased tropospheric temperatures. By means of numerical simulations with a general circulation and chemistry model of the entire atmosphere we will address the following questions: 1.) Can state-of-the-art atmospheric modeling explain the mesospheric temperature trends observed during the last decades? 2.)Which part of the temperature changes resulting from an increase of atmospheric CO2 is caused by local changes in the radiative budget and which part is influenced by remote dynamical effects? The model used is the newly developed Hamburg Model of the Neutral and Ionized Atmosphere (HAMMONIA) that resolves the atmosphere from the Earth's surface up to about 250 km altitude, and is based on the 3-D dynamics from the ECHAM5 general circulation model and the chemistry scheme from MOZART-3. Results from different time slice experiment representative of years 1970 and 2000, and for a doubling of CO2 will be presented.

  17. Estimating temporal trend in the presence of spatial complexity: A Bayesian hierarchical model for a wetland plant population undergoing restoration

    Science.gov (United States)

    Rodhouse, T.J.; Irvine, K.M.; Vierling, K.T.; Vierling, L.A.

    2011-01-01

    Monitoring programs that evaluate restoration and inform adaptive management are important for addressing environmental degradation. These efforts may be well served by spatially explicit hierarchical approaches to modeling because of unavoidable spatial structure inherited from past land use patterns and other factors. We developed Bayesian hierarchical models to estimate trends from annual density counts observed in a spatially structured wetland forb (Camassia quamash [camas]) population following the cessation of grazing and mowing on the study area, and in a separate reference population of camas. The restoration site was bisected by roads and drainage ditches, resulting in distinct subpopulations ("zones") with different land use histories. We modeled this spatial structure by fitting zone-specific intercepts and slopes. We allowed spatial covariance parameters in the model to vary by zone, as in stratified kriging, accommodating anisotropy and improving computation and biological interpretation. Trend estimates provided evidence of a positive effect of passive restoration, and the strength of evidence was influenced by the amount of spatial structure in the model. Allowing trends to vary among zones and accounting for topographic heterogeneity increased precision of trend estimates. Accounting for spatial autocorrelation shifted parameter coefficients in ways that varied among zones depending on strength of statistical shrinkage, autocorrelation and topographic heterogeneity-a phenomenon not widely described. Spatially explicit estimates of trend from hierarchical models will generally be more useful to land managers than pooled regional estimates and provide more realistic assessments of uncertainty. The ability to grapple with historical contingency is an appealing benefit of this approach.

  18. Trend and forecasting rate of cancer deaths at a public university hospital using univariate modeling

    Science.gov (United States)

    Ismail, A.; Hassan, Noor I.

    2013-09-01

    Cancer is one of the principal causes of death in Malaysia. This study was performed to determine the pattern of rate of cancer deaths at a public hospital in Malaysia over an 11 year period from year 2001 to 2011, to determine the best fitted model of forecasting the rate of cancer deaths using Univariate Modeling and to forecast the rates for the next two years (2012 to 2013). The medical records of the death of patients with cancer admitted at this Hospital over 11 year's period were reviewed, with a total of 663 cases. The cancers were classified according to 10th Revision International Classification of Diseases (ICD-10). Data collected include socio-demographic background of patients such as registration number, age, gender, ethnicity, ward and diagnosis. Data entry and analysis was accomplished using SPSS 19.0 and Minitab 16.0. The five Univariate Models used were Naïve with Trend Model, Average Percent Change Model (ACPM), Single Exponential Smoothing, Double Exponential Smoothing and Holt's Method. The overall 11 years rate of cancer deaths showed that at this hospital, Malay patients have the highest percentage (88.10%) compared to other ethnic groups with males (51.30%) higher than females. Lung and breast cancer have the most number of cancer deaths among gender. About 29.60% of the patients who died due to cancer were aged 61 years old and above. The best Univariate Model used for forecasting the rate of cancer deaths is Single Exponential Smoothing Technique with alpha of 0.10. The forecast for the rate of cancer deaths shows a horizontally or flat value. The forecasted mortality trend remains at 6.84% from January 2012 to December 2013. All the government and private sectors and non-governmental organizations need to highlight issues on cancer especially lung and breast cancers to the public through campaigns using mass media, media electronics, posters and pamphlets in the attempt to decrease the rate of cancer deaths in Malaysia.

  19. The comet assay in higher terrestrial plant model: Review and evolutionary trends.

    Science.gov (United States)

    Lanier, Caroline; Manier, Nicolas; Cuny, Damien; Deram, Annabelle

    2015-12-01

    The comet assay is a sensitive technique for the measurement of DNA damage in individual cells. Although it has been primarily applied to animal cells, its adaptation to higher plant tissues significantly extends the utility of plants for environmental genotoxicity research. The present review focuses on 101 key publications and discusses protocols and evolutionary trends specific to higher plants. General consensus validates the use of the percentage of DNA found in the tail, the alkaline version of the test and root study. The comet protocol has proved its effectiveness and its adaptability for cultivated plant models. Its transposition in wild plants thus appears as a logical evolution. However, certain aspects of the protocol can be improved, namely through the systematic use of positive controls and increasing the number of nuclei read. These optimizations will permit the increase in the performance of this test, namely when interpreting mechanistic and physiological phenomena.

  20. Transport and Environment Database System (TRENDS): Maritime Air Pollutant Emission Modelling

    DEFF Research Database (Denmark)

    Georgakaki, Aliki; Coffey, R. A.; Lock, G.

    2003-01-01

    encountered since the statistical data collection was not undertaken with a view to this purpose are mentioned. Examples of the results obtained by the database are presented. These include detailed air pollutant emission results per port and vessel type, to aggregate results for different types of movements......This paper reports the development of the maritime module within the framework of the TRENDS project. A detailed database has been constructed, which includes all stages of the energy consumption and air pollutant emission calculations. The technical assumptions and factors incorporated...... in the database are presented, including changes from MEET findings. The database operates on statistical data provided by Eurostat. Data is at port to MCA level, so a bottom-up approach is used. This was the first attempt to use Eurostat maritime statistics for emission modelling, and the problems that have been...

  1. Trends in modelling neutral-atmospheric electromagnetic delays in a `big data' world

    Science.gov (United States)

    Santos, Marcelo

    -atmosphere at any given time, as readily and as accurately as possible. This situation fits well within what today is known as big data. This paper will explore and discuss scenarios that have potential to open new trends in modeling the neutral-atmospheric delay. They include near real-time empirical model updates, sequential improvement of Marini mapping function coefficients (e.g., within a VMF) and a self-feeding NWP. Being within the context of GGOS and GEOSS, the discussion and simulations that will be shown cover the whole planet. The pros and cons of each approach will be discussed in comparison with what is done today. Simulations show potential improvement of up to 25% under certain circumstances.

  2. Sea Ice Trends in the AO-UMUKCA model: Interplay of Forcing and Internal Variability

    Science.gov (United States)

    Jrrar, Amna; Abraham, Luke; Holland, David; Pyle, John

    2016-04-01

    While Arctic Sea is showing a declining trend particularly in summer. Antarctic sea is showing a modest increase, a very controversial observation in a warming climate. Several studies have attributed these changes to internal variability. Hence in this paper we investigate sea ice trends in both hemispheres as simulated in a version of the Atmosphere-Ocean coupled chemistry climate model AO-UMUKCA under two different atmospheric forcing scenarios. One simulation is a pre-industrial control, where atmospheric forcing is fixed at 1850 level. The second simulation is also a time slice experiment but forced with the year 2000 atmospheric forcing (TS2000). The model simulates a significant reduction in NH Sea Ice Extent (SIE) under the TS2000 scenario, but shows negligible difference in SH SIE between the two scenarios. In agreement with observational studies, we find that NH SIE and distribution are connected to the Arctic Oscillation and the Dipole Anomaly in both simulations, particularly in summer time. While SH winter SIE shows a high correlation with zonal wave-3 pattern and the Pacific South American mode, particularly in TS2000. Connections between SIE and oceanic modes of variability in both hemispheres are also detected. Total NH SIE shows significant correlation with Atlantic Multidecadal Oscillation (AMO) on interannual and decadal timescales, but shows significant correlation with the Inter Pacific Decadal Oscillation (IPO) on multi-decadal timescale only. However, total SH SIE shows significant correlation only with IPO on decadal and multi-decadal scales. The SIE response to oceanic modes is comparable in both simulations.

  3. Comparison of the neuropathological characteristics of bovine spongiform encephalopathy (BSE) and variant Creutzfeldt-Jakob disease (vCJD) in mice.

    Science.gov (United States)

    Brown, D A; Bruce, M E; Fraser, J R

    2003-06-01

    Bovine spongiform encephalopathy (BSE) and variant Creutzfeldt-Jakob disease (vCJD) belong to a group of diseases called the transmissible spongiform encephalopathies (TSEs). Transmission studies in inbred mice (strain typing) provided overwhelming evidence that vCJD arose from BSE. In this study, we compare the patterns of neuropathology in a panel of three inbred mouse strains (RIII, C57BL and VM) and one cross (C57BL x VM) infected with either vCJD or BSE. For each mouse strain, patterns of abnormal prion protein (PrPres) deposition, astrocytosis and vacuolation were similar in the vCJD- and BSE-challenged mice. Prion protein (PrP)-positive plaques were prominent in the VM and C57BL x VM mice in addition to diffuse PrPres accumulation, whereas only diffuse PrPres labelling was observed in the RIII and C57BL mice. The hippocampus was targeted in all mouse strains, as was the cochlear nucleus in the medulla, both showing consistent severe vacuolation and heavy PrPres deposition. Although the targeting of PrPres was similar in the BSE- and vCJD-infected brains, the amount and intensity of PrPres observed in the brains treated with formic acid during fixation was reduced considerably. The distribution of astrocytosis was similar to the targeting of PrPres deposition in the brain, although some differences were observed in the hippocampi of mice challenged with vCJD. We conclude that there are no significant differences in the targeting of neuropathological changes observed in the BSE- and vCJD-infected mice, consistent with the previous evidence of a link between BSE and vCJD.

  4. Recent trends of high-latitude vegetation activity assessed and explained by contrasting modelling approaches with earth observation data

    Science.gov (United States)

    Forkel, M.; Carvalhais, N.; Reichstein, M.; Thonicke, K.

    2012-04-01

    Satellite observations of Normalized Difference Vegetation Index (NDVI) showed increasing trends in the arctic tundra and the boreal forests since the 1980s. This greening is related to an increase in photosynthetic activity and is driven by increasing temperatures and a prolongation of the growing season. However, NDVI experienced a decrease in large regions of the boreal forests since the mid-1990s. This browning is related to fire disturbances, temperature-induced summer drought and potentially to insect infestations and diseases. Terrestrial biosphere models (TBM) can be used to assess the impacts of these changes in vegetation productivity on the carbon and water cycles and on the climate system. In general, these models provide descriptions of ecosystem processes and states that are forced by and feedback to the climate system such as photosynthesis and transpiration, ecosystem respiration, soil carbon and water stocks and vegetation composition. The evaluation of TBMs against observations is a necessary step to assess their suitability to simulate such processes and dynamics. The increasing availability of long-term observations of vegetation activity enables us to evaluate the model ability to diagnose these vegetation greening and browning trends in arctic and boreal regions. The first aim of this study is to evaluate trends in vegetation activity in high-latitude regions as simulated by TBMs against observed trends in vegetation activity. The second aim is to identify potential drivers of these observed and simulated trends to evaluate the ability of models to reproduce the observed functional relations between climatic and environmental drivers and the vegetation trends. The trends in vegetation activity were estimated for a set of satellite-based remote sensing products: NDVI from AVHRR (Advanced Very High Resolution Radiometer) and MODIS (Moderate Resolution Imaging Spectrometer), as well as FAPAR observations (Fraction of Observed Photosynthetically

  5. Multiscale Modeling of Multi-decadal Trends in Ozone and Precursor Species Across the Northern Hemisphere and the United States

    Science.gov (United States)

    Multi-decadal model calculations for the 1990-2010 period are performed with the coupled WRF-CMAQ modeling system over a domain encompassing the northern hemisphere and a nested domain over the continental U.S. Simulated trends in ozone and precursor species concentrations acros...

  6. The contribution of anthropogenic bromine emissions to past stratospheric ozone trends: a modelling study

    Directory of Open Access Journals (Sweden)

    B.-M. Sinnhuber

    2009-04-01

    Full Text Available Bromine compounds play an important role in the depletion of stratospheric ozone. We have calculated the changes in stratospheric ozone in response to changes in the halogen loading over the past decades, using a two-dimensional (latitude/height model constrained by source gas mixing ratios at the surface. Model calculations of the decrease of total column ozone since 1980 agree reasonably well with observed ozone trends, in particular when the contribution from very short-lived bromine compounds is included. Model calculations with bromine source gas mixing ratios fixed at 1959 levels, corresponding approximately to a situation with no anthropogenic bromine emissions, show an ozone column reduction between 1980 and 2005 at Northern Hemisphere mid-latitudes of only ≈55% compared to a model run including all halogen source gases. In this sense anthropogenic bromine emissions are responsible for ≈45% of the model estimated column ozone loss at Northern Hemisphere mid-latitudes. However, since a large fraction of the bromine induced ozone loss is due to the combined BrO/ClO catalytic cycle, the effect of bromine would have been smaller in the absence of anthropogenic chlorine emissions. The chemical efficiency of bromine relative to chlorine for global total ozone depletion from our model calculations, expressed by the so called α-factor, is 64 on an annual average. This value is much higher than previously published results. Updates in reaction rate constants can explain only part of the differences in α. The inclusion of bromine from very short-lived source gases has only a minor effect on the global mean α-factor.

  7. Predicting of trend of hemoglobin a1c in type 2 diabetes: a longitudinal linear mixed model.

    Science.gov (United States)

    Kazemi, Elahe; Hosseini, Seyed Mohsen; Bahrampour, Abbass; Faghihimani, Elham; Amini, Masood

    2014-10-01

    There are some evidences that control the blood sugar decreasing the risk of diabetes complications, and even fatal. There are so many studies, but they are mostly cross-sectional and ignore the trend and hence it is necessary to implement a longitudinal study. The aim of this prospective study is to find the trend of glycosylated hemoglobin (HbA1c) over time and the associative factors on it. Participants of this longitudinal study were 3440 eligible diabetes patients referred to Isfahan Endocrine and Metabolism Research Center during 2000-2012 who are measured 2-40 times. A linear mixed model was applied to determine the association between HbA1c and variables, including lipids, systolic, diastolic blood pressure and complications such as nephropathy, and retinopathy. Furthermore, the effect of mentioned variables on trend of HbA1c was determined. The fitted model showed total cholesterol, retinopathy, and the method of therapy including oral antidiabetic drugs (OADs) plus insulin and insulin therapy decreased the trend of HbA1c and high-density lipoprotein, weight, hyperlipidemia and the method of therapy including diet, and OADs increased the trend of HbA1c. The present study shows that regular visits of diabetic patients as well as controlling blood pressure, lipid profile, and weight loss can improve the trend of HbA1c levels during the time.

  8. An Effective Time Series Analysis for Stock Trend Prediction Using ARIMA Model for Nifty Midcap-50

    Directory of Open Access Journals (Sweden)

    B.Uma Devi

    2013-01-01

    Full Text Available The data mining and its tool has played a vital role in exploring the data from different ware houses. Using data mining tools and analytical technologies we do a quantifiable amount of research to explore new approach for the investment decisions .The market with huge volume of investor with good enough knowledge and have a prediction as well as control over their investments. The stock market some time fails to attract new investor. The reason states that non-aware and also people don’t want to come forward to fall in to the risk. An approach with adequate expertise is designed to help investors to ascertain veiled patterns from the historic data that have feasible predictive ability in their investment decisions. In this paper the NSE – Nifty Midcap50 companies among them top 4 companies having max Midcap value has been selected for analysis. The historical data has a significant role in, helping the investing people to get an overview about the market behavior during the past decade. The stock data for the past five years has been collected and trained using ARIMA model with different parameters. The test criterions like Akaike Information Criterion Bayesian Information Criterion (AICBIC are applied to predict the accuracy of the model. The performance of the trained model is analyzed and it also tested to find the trend and the market behavior for future forecast.

  9. Modelling spatial patterns and temporal trends of wildfires in Galicia (NW Spain

    Directory of Open Access Journals (Sweden)

    Jesús Barreal

    2015-08-01

    Full Text Available Aim of study: The goal of this paper is to analyse the importance of the main contributing factors to the occurrence of wildfires. Area of study: We employ data from the region of Galicia during 2001-2010; although the similarities shared between this area and other rural areas may allow extrapolation of the present results. Material and Methods: The spatial dependence is analysed by using the Moran’s I and LISA statistics. We also conduct an econometric analysis modelling both, the number of fires and the relative size of afflicted woodland area as dependent variables, which depend on the climatic, land cover variables, and socio-economic characteristics of the affected areas. Fixed effects and random effect models are estimated in order to control for the heterogeneity between the Forest Districts in Galicia. Main results: Moran’s I and LISA statistics show that there is spatial dependence in the occurrence of Galician wildfires. Econometrics models show that climatology, socioeconomic variables, and temporal trends are also important to study both, the number of wildfires and the burned-forest ratio. Research highlights: We conclude that in addition to direct forest actions, other agricultural or social public plans, can help to reduce wildfires in rural areas or wildland-urban areas. Based on these conclusions, a number of guidelines are provided that may foster the development of better forest management policies in order to reduce the occurrence of wildfires.

  10. Systematic trends in total-mass profiles from dynamical models of early-type galaxies

    Science.gov (United States)

    Poci, Adriano; Cappellari, Michele; McDermid, Richard M.

    2017-01-01

    We study trends in the slope of the total mass profiles and dark matter fractions within the central half-light radius of 258 early-type galaxies, using data from the volume-limited ATLAS3D survey. We use three distinct sets of dynamical models, which vary in their assumptions and also allow for spatial variations in the stellar mass-to-light ratio, to test the robustness of our results. We confirm that the slopes of the total mass profiles are approximately isothermal, and investigate how the total-mass slope depends on various galactic properties. The most statistically-significant correlations we find are a function of either surface density, Σe, or velocity dispersion, σe. However there is evidence for a break in the latter relation, with a nearly universal logarithmic slope above log10[σe/(km s-1)] ˜ 2.1 and a steeper trend below this value. For the 142 galaxies above that critical σe value, the total mass-density logarithmic slopes have a mean value = -2.193 ± 0.016 (1σ error) with an observed rms scatter of only σ _{γ ^' }= 0.168 ± 0.015. Considering the observational errors, we estimate an intrinsic scatter of σ _{γ ^' }^intr ≈ 0.15. These values are broadly consistent with those found by strong lensing studies at similar radii and agree, within the tight errors, with values recently found at much larger radii via stellar dynamics or HI rotation curves (using significantly smaller samples than this work).

  11. Assessment of climate change impacts on climate variables using probabilistic ensemble modeling and trend analysis

    Science.gov (United States)

    Safavi, Hamid R.; Sajjadi, Sayed Mahdi; Raghibi, Vahid

    2016-08-01

    Water resources in snow-dependent regions have undergone significant changes due to climate change. Snow measurements in these regions have revealed alarming declines in snowfall over the past few years. The Zayandeh-Rud River in central Iran chiefly depends on winter falls as snow for supplying water from wet regions in high Zagrous Mountains to the downstream, (semi-)arid, low-lying lands. In this study, the historical records (baseline: 1971-2000) of climate variables (temperature and precipitation) in the wet region were chosen to construct a probabilistic ensemble model using 15 GCMs in order to forecast future trends and changes while the Long Ashton Research Station Weather Generator (LARS-WG) was utilized to project climate variables under two A2 and B1 scenarios to a future period (2015-2044). Since future snow water equivalent (SWE) forecasts by GCMs were not available for the study area, an artificial neural network (ANN) was implemented to build a relationship between climate variables and snow water equivalent for the baseline period to estimate future snowfall amounts. As a last step, homogeneity and trend tests were performed to evaluate the robustness of the data series and changes were examined to detect past and future variations. Results indicate different characteristics of the climate variables at upstream stations. A shift is observed in the type of precipitation from snow to rain as well as in its quantities across the subregions. The key role in these shifts and the subsequent side effects such as water losses is played by temperature.

  12. A Dynamic Spreadsheet Model for Determining the Portfolio Frontier for BSE30 Stocks

    Directory of Open Access Journals (Sweden)

    Dr. Anupam Mitra

    2014-01-01

    Full Text Available Introductory investments courses revolve around Harry Markowitz’s modern portfolio theory and William Sharpe’s Index for the performance measurement of those portfolios. This paper presents a simplified perspective of Markowitz’s contributions to Modern Portfolio Theory. It is to see the effect of duration of historical data on the risk and return of the portfolio and to see the applicability of risk-reward logic. The empirical results also show that short selling may increase the risk of the portfolio when the investor is instability preferred.

  13. A New-Trend Model-Based to Solve the Peak Power Problems in OFDM Systems

    Directory of Open Access Journals (Sweden)

    Ashraf A. Eltholth

    2008-01-01

    Full Text Available The high peak to average power ration (PAR levels of orthogonal frequency division multiplexing (OFDM signals attract the attention of many researchers during the past decade. Existing approaches that attack this PAR issue are abundant, but no systematic framework or comparison between them exists to date. They sometimes even differ in the problem definition itself and consequently in the basic approach to follow. In this paper, we propose a new trend in mitigating the peak power problem in OFDM system based on modeling the effects of clipping and amplifier nonlinearities in an OFDM system. We showed that the distortion due to these effects is highly related to the dynamic range itself rather than the clipping level or the saturation level of the nonlinear amplifier, and thus we propose two criteria to reduce the dynamic range of the OFDM, namely, the use of MSK modulation and the use of Hadamard transform. Computer simulations of the OFDM system using Matlab are completely matched with the deduced model in terms of OFDM signal quality metrics such as BER, ACPR, and EVM. Also simulation results show that even the reduction of PAR using the two proposed criteria is not significat, and the reduction in the amount of distortion due to HPA is truley delightful.

  14. Ecosystem services sustainability in the Mediterranean Sea: assessment of status and trends using multiple modelling approaches

    Science.gov (United States)

    Liquete, Camino; Piroddi, Chiara; Macías, Diego; Druon, Jean-Noël; Zulian, Grazia

    2016-09-01

    Mediterranean ecosystems support important processes and functions that bring direct benefits to human society. Yet, marine ecosystem services are usually overlooked due to the challenges in identifying and quantifying them. This paper proposes the application of several biophysical and ecosystem modelling approaches to assess spatially and temporally the sustainable use and supply of selected marine ecosystem services. Such services include food provision, water purification, coastal protection, lifecycle maintenance and recreation, focusing on the Mediterranean region. Overall, our study found a higher number of decreasing than increasing trends in the natural capacity of the ecosystems to provide marine and coastal services, while in contrast the opposite was observed to be true for the realised flow of services to humans. Such a study paves the way towards an effective support for Blue Growth and the European maritime policies, although little attention is paid to the quantification of marine ecosystem services in this context. We identify a key challenge of integrating biophysical and socio-economic models as a necessary step to further this research.

  15. Ecosystem services sustainability in the Mediterranean Sea: assessment of status and trends using multiple modelling approaches

    Science.gov (United States)

    Liquete, Camino; Piroddi, Chiara; Macías, Diego; Druon, Jean-Noël; Zulian, Grazia

    2016-01-01

    Mediterranean ecosystems support important processes and functions that bring direct benefits to human society. Yet, marine ecosystem services are usually overlooked due to the challenges in identifying and quantifying them. This paper proposes the application of several biophysical and ecosystem modelling approaches to assess spatially and temporally the sustainable use and supply of selected marine ecosystem services. Such services include food provision, water purification, coastal protection, lifecycle maintenance and recreation, focusing on the Mediterranean region. Overall, our study found a higher number of decreasing than increasing trends in the natural capacity of the ecosystems to provide marine and coastal services, while in contrast the opposite was observed to be true for the realised flow of services to humans. Such a study paves the way towards an effective support for Blue Growth and the European maritime policies, although little attention is paid to the quantification of marine ecosystem services in this context. We identify a key challenge of integrating biophysical and socio-economic models as a necessary step to further this research. PMID:27686533

  16. Noise modeling by the trend of each range gate for coherent Doppler LIDAR

    Science.gov (United States)

    Bu, Zhichao; Zhang, Yinchao; Chen, Siying; Guo, Pan; Li, Lu; Chen, He

    2014-06-01

    A denoising method of all-fiber pulsed coherent Doppler LIDAR (CDL) is investigated. The goal is to enhance the signal-to-noise ratio (SNR) in the weak signal regime. Based on differential detection theory, the total noise expression of CDL with a dual-balanced detector is introduced and analyzed. The conclusion is drawn that the total noise can be acquired under the local oscillator laser exposure conditions by reasonable simplification. Using the actual measured data, the ratio of the standard deviation to the mean value of the total noise in each range gate is obtained and is up to approximately 11%. In order to suppress the jitter of the noise, an effective noise modeling by the trend of each range gate is developed. The feasibility of this method is verified by a long set of measured data. The spatial and temporal distribution of wind speed is illustrated with 400 pulses accumulation. Compared to the noise modeling of the tail, the detection range of wind speed using the proposed method can be improved by 35.3%.

  17. How the surveillance system may bias the results of analytical epidemiological studies on BSE: prevalence among dairy versus beef suckler cattle breeds in France.

    Science.gov (United States)

    Ducrot, Christian; Roy, Pascal; Morignat, Eric; Baron, Thierry; Calavas, Didier

    2003-01-01

    Until recently, epidemiological studies on Bovine Spongiform Encephalopathy (BSE) were based on Mandatory Reporting Systems (MRS) of clinically suspect bovines only, but rapid diagnostic tests were validated in 1999 and are used for targeted surveillance in Switzerland, France and other countries, as a complementary and secondary tool. Data on 30491 cattle issued from a French pilot program targeted at cattle having died on the farm, subjected to euthanasia or sent for emergency slaughter, did not show any significant difference in BSE risk between dairy and beef suckler breeds. The data also revealed that part of the clinical cases of BSE escaped the MRS, which permitted to detect more dairy than beef suckler affected cattle compared to the targeted surveillance in the same period (from August to December 2000) and region (Bretagne, Pays de la Loire and Basse Normandie regions). Analyzing together the data of the targeted surveillance and mandatory reporting system programs with a non-conditional logistic regression, we found that the odds of a dead cow being a BSE case among all dead cattle was 3.2 times higher for dairy breeds compared to beef suckler breeds. This confirmed British findings but points out to the fact that considering either MRS or targeted surveillance data alone may possibly create biases in epidemiological studies on BSE.

  18. A COMPARATIVE STUDY OF FORECASTING MODELS FOR TREND AND SEASONAL TIME SERIES DOES COMPLEX MODEL ALWAYS YIELD BETTER FORECAST THAN SIMPLE MODELS

    Directory of Open Access Journals (Sweden)

    Suhartono Suhartono

    2005-01-01

    Full Text Available Many business and economic time series are non-stationary time series that contain trend and seasonal variations. Seasonality is a periodic and recurrent pattern caused by factors such as weather, holidays, or repeating promotions. A stochastic trend is often accompanied with the seasonal variations and can have a significant impact on various forecasting methods. In this paper, we will investigate and compare some forecasting methods for modeling time series with both trend and seasonal patterns. These methods are Winter's, Decomposition, Time Series Regression, ARIMA and Neural Networks models. In this empirical research, we study on the effectiveness of the forecasting performance, particularly to answer whether a complex method always give a better forecast than a simpler method. We use a real data, that is airline passenger data. The result shows that the more complex model does not always yield a better result than a simpler one. Additionally, we also find the possibility to do further research especially the use of hybrid model by combining some forecasting method to get better forecast, for example combination between decomposition (as data preprocessing and neural network model.

  19. EURODELTA-Trends, a multi-model experiment of air quality hindcast in Europe over 1990-2010

    Science.gov (United States)

    Colette, Augustin; Andersson, Camilla; Manders, Astrid; Mar, Kathleen; Mircea, Mihaela; Pay, Maria-Teresa; Raffort, Valentin; Tsyro, Svetlana; Cuvelier, Cornelius; Adani, Mario; Bessagnet, Bertrand; Bergström, Robert; Briganti, Gino; Butler, Tim; Cappelletti, Andrea; Couvidat, Florian; D'Isidoro, Massimo; Doumbia, Thierno; Fagerli, Hilde; Granier, Claire; Heyes, Chris; Klimont, Zig; Ojha, Narendra; Otero, Noelia; Schaap, Martijn; Sindelarova, Katarina; Stegehuis, Annemiek I.; Roustan, Yelva; Vautard, Robert; van Meijgaard, Erik; Garcia Vivanco, Marta; Wind, Peter

    2017-09-01

    The EURODELTA-Trends multi-model chemistry-transport experiment has been designed to facilitate a better understanding of the evolution of air pollution and its drivers for the period 1990-2010 in Europe. The main objective of the experiment is to assess the efficiency of air pollutant emissions mitigation measures in improving regional-scale air quality. The present paper formulates the main scientific questions and policy issues being addressed by the EURODELTA-Trends modelling experiment with an emphasis on how the design and technical features of the modelling experiment answer these questions. The experiment is designed in three tiers, with increasing degrees of computational demand in order to facilitate the participation of as many modelling teams as possible. The basic experiment consists of simulations for the years 1990, 2000, and 2010. Sensitivity analysis for the same three years using various combinations of (i) anthropogenic emissions, (ii) chemical boundary conditions, and (iii) meteorology complements it. The most demanding tier consists of two complete time series from 1990 to 2010, simulated using either time-varying emissions for corresponding years or constant emissions. Eight chemistry-transport models have contributed with calculation results to at least one experiment tier, and five models have - to date - completed the full set of simulations (and 21-year trend calculations have been performed by four models). The modelling results are publicly available for further use by the scientific community. The main expected outcomes are (i) an evaluation of the models' performances for the three reference years, (ii) an evaluation of the skill of the models in capturing observed air pollution trends for the 1990-2010 time period, (iii) attribution analyses of the respective role of driving factors (e.g. emissions, boundary conditions, meteorology), (iv) a dataset based on a multi-model approach, to provide more robust model results for use in impact

  20. Current Trends in the Detection of Sociocultural Signatures: Data-Driven Models

    Energy Technology Data Exchange (ETDEWEB)

    Sanfilippo, Antonio P.; Bell, Eric B.; Corley, Courtney D.

    2014-09-15

    available that are shaping social computing as a strongly data-driven experimental discipline with an increasingly stronger impact on the decision-making process of groups and individuals alike. In this chapter, we review current advances and trends in the detection of sociocultural signatures. Specific embodiments of the issues discussed are provided with respect to the assessment of violent intent and sociopolitical contention. We begin by reviewing current approaches to the detection of sociocultural signatures in these domains. Next, we turn to the review of novel data harvesting methods for social media content. Finally, we discuss the application of sociocultural models to social media content, and conclude by commenting on current challenges and future developments.

  1. Cellular Scanning Strategy for Selective Laser Melting: Capturing Thermal Trends with a Low-Fidelity, Pseudo-Analytical Model

    Directory of Open Access Journals (Sweden)

    Sankhya Mohanty

    2014-01-01

    Full Text Available Simulations of additive manufacturing processes are known to be computationally expensive. The resulting large runtimes prohibit their application in secondary analysis requiring several complete simulations such as optimization studies, and sensitivity analysis. In this paper, a low-fidelity pseudo-analytical model has been introduced to enable such secondary analysis. The model has been able to mimic a finite element model and was able to capture the thermal trends associated with the process. The model has been validated and subsequently applied in a small optimization case study. The pseudo-analytical modelling technique is established as a fast tool for primary modelling investigations.

  2. Modeling pollen time series using seasonal-trend decomposition procedure based on LOESS smoothing.

    Science.gov (United States)

    Rojo, Jesús; Rivero, Rosario; Romero-Morte, Jorge; Fernández-González, Federico; Pérez-Badia, Rosa

    2017-02-01

    Analysis of airborne pollen concentrations provides valuable information on plant phenology and is thus a useful tool in agriculture-for predicting harvests in crops such as the olive and for deciding when to apply phytosanitary treatments-as well as in medicine and the environmental sciences. Variations in airborne pollen concentrations, moreover, are indicators of changing plant life cycles. By modeling pollen time series, we can not only identify the variables influencing pollen levels but also predict future pollen concentrations. In this study, airborne pollen time series were modeled using a seasonal-trend decomposition procedure based on LOcally wEighted Scatterplot Smoothing (LOESS) smoothing (STL). The data series-daily Poaceae pollen concentrations over the period 2006-2014-was broken up into seasonal and residual (stochastic) components. The seasonal component was compared with data on Poaceae flowering phenology obtained by field sampling. Residuals were fitted to a model generated from daily temperature and rainfall values, and daily pollen concentrations, using partial least squares regression (PLSR). This method was then applied to predict daily pollen concentrations for 2014 (independent validation data) using results for the seasonal component of the time series and estimates of the residual component for the period 2006-2013. Correlation between predicted and observed values was r = 0.79 (correlation coefficient) for the pre-peak period (i.e., the period prior to the peak pollen concentration) and r = 0.63 for the post-peak period. Separate analysis of each of the components of the pollen data series enables the sources of variability to be identified more accurately than by analysis of the original non-decomposed data series, and for this reason, this procedure has proved to be a suitable technique for analyzing the main environmental factors influencing airborne pollen concentrations.

  3. Modeling pollen time series using seasonal-trend decomposition procedure based on LOESS smoothing

    Science.gov (United States)

    Rojo, Jesús; Rivero, Rosario; Romero-Morte, Jorge; Fernández-González, Federico; Pérez-Badia, Rosa

    2016-08-01

    Analysis of airborne pollen concentrations provides valuable information on plant phenology and is thus a useful tool in agriculture—for predicting harvests in crops such as the olive and for deciding when to apply phytosanitary treatments—as well as in medicine and the environmental sciences. Variations in airborne pollen concentrations, moreover, are indicators of changing plant life cycles. By modeling pollen time series, we can not only identify the variables influencing pollen levels but also predict future pollen concentrations. In this study, airborne pollen time series were modeled using a seasonal-trend decomposition procedure based on LOcally wEighted Scatterplot Smoothing (LOESS) smoothing (STL). The data series—daily Poaceae pollen concentrations over the period 2006-2014—was broken up into seasonal and residual (stochastic) components. The seasonal component was compared with data on Poaceae flowering phenology obtained by field sampling. Residuals were fitted to a model generated from daily temperature and rainfall values, and daily pollen concentrations, using partial least squares regression (PLSR). This method was then applied to predict daily pollen concentrations for 2014 (independent validation data) using results for the seasonal component of the time series and estimates of the residual component for the period 2006-2013. Correlation between predicted and observed values was r = 0.79 (correlation coefficient) for the pre-peak period (i.e., the period prior to the peak pollen concentration) and r = 0.63 for the post-peak period. Separate analysis of each of the components of the pollen data series enables the sources of variability to be identified more accurately than by analysis of the original non-decomposed data series, and for this reason, this procedure has proved to be a suitable technique for analyzing the main environmental factors influencing airborne pollen concentrations.

  4. Modeling pollen time series using seasonal-trend decomposition procedure based on LOESS smoothing

    Science.gov (United States)

    Rojo, Jesús; Rivero, Rosario; Romero-Morte, Jorge; Fernández-González, Federico; Pérez-Badia, Rosa

    2017-02-01

    Analysis of airborne pollen concentrations provides valuable information on plant phenology and is thus a useful tool in agriculture—for predicting harvests in crops such as the olive and for deciding when to apply phytosanitary treatments—as well as in medicine and the environmental sciences. Variations in airborne pollen concentrations, moreover, are indicators of changing plant life cycles. By modeling pollen time series, we can not only identify the variables influencing pollen levels but also predict future pollen concentrations. In this study, airborne pollen time series were modeled using a seasonal-trend decomposition procedure based on LOcally wEighted Scatterplot Smoothing (LOESS) smoothing (STL). The data series—daily Poaceae pollen concentrations over the period 2006-2014—was broken up into seasonal and residual (stochastic) components. The seasonal component was compared with data on Poaceae flowering phenology obtained by field sampling. Residuals were fitted to a model generated from daily temperature and rainfall values, and daily pollen concentrations, using partial least squares regression (PLSR). This method was then applied to predict daily pollen concentrations for 2014 (independent validation data) using results for the seasonal component of the time series and estimates of the residual component for the period 2006-2013. Correlation between predicted and observed values was r = 0.79 (correlation coefficient) for the pre-peak period (i.e., the period prior to the peak pollen concentration) and r = 0.63 for the post-peak period. Separate analysis of each of the components of the pollen data series enables the sources of variability to be identified more accurately than by analysis of the original non-decomposed data series, and for this reason, this procedure has proved to be a suitable technique for analyzing the main environmental factors influencing airborne pollen concentrations.

  5. Using trend templates in a neonatal seizure algorithm improves detection of short seizures in a foetal ovine model.

    Science.gov (United States)

    Zwanenburg, Alex; Andriessen, Peter; Jellema, Reint K; Niemarkt, Hendrik J; Wolfs, Tim G A M; Kramer, Boris W; Delhaas, Tammo

    2015-03-01

    Seizures below one minute in duration are difficult to assess correctly using seizure detection algorithms. We aimed to improve neonatal detection algorithm performance for short seizures through the use of trend templates for seizure onset and end. Bipolar EEG were recorded within a transiently asphyxiated ovine model at 0.7 gestational age, a common experimental model for studying brain development in humans of 30-34 weeks of gestation. Transient asphyxia led to electrographic seizures within 6-8 h. A total of 3159 seizures, 2386 shorter than one minute, were annotated in 1976 h-long EEG recordings from 17 foetal lambs. To capture EEG characteristics, five features, sensitive to seizures, were calculated and used to derive trend information. Feature values and trend information were used as input for support vector machine classification and subsequently post-processed. Performance metrics, calculated after post-processing, were compared between analyses with and without employing trend information. Detector performance was assessed after five-fold cross-validation conducted ten times with random splits. The use of trend templates for seizure onset and end in a neonatal seizure detection algorithm significantly improves the correct detection of short seizures using two-channel EEG recordings from 54.3% (52.6-56.1) to 59.5% (58.5-59.9) at FDR 2.0 (median (range); p seizures by EEG monitoring at the NICU.

  6. Regression model analysis of the decreasing trend of cesium-137 concentration in the atmosphere since the Fukushima accident.

    Science.gov (United States)

    Kitayama, Kyo; Ohse, Kenji; Shima, Nagayoshi; Kawatsu, Kencho; Tsukada, Hirofumi

    2016-11-01

    The decreasing trend of the atmospheric (137)Cs concentration in two cities in Fukushima prefecture was analyzed by a regression model to clarify the relation between the parameter of the decrease in the model and the trend and to compare the trend with that after the Chernobyl accident. The (137)Cs particle concentration measurements were conducted in urban Fukushima and rural Date sites from September 2012 to June 2015. The (137)Cs particle concentrations were separated in two groups: particles of more than 1.1 μm aerodynamic diameters (coarse particles) and particles with aerodynamic diameter lower than 1.1 μm (fine particles). The averages of the measured concentrations were 0.1 mBq m(-3) in Fukushima and Date sites. The measured concentrations were applied in the regression model which decomposed them into two components: trend and seasonal variation. The trend concentration included the parameters for the constant and the exponential decrease. The parameter for the constant was slightly different between the Fukushima and Date sites. The parameter for the exponential decrease was similar for all the cases, and much higher than the value of the physical radioactive decay except for the concentration in the fine particles at the Date site. The annual decreasing rates of the (137)Cs concentration evaluated by the trend concentration ranged from 44 to 53% y(-1) with average and standard deviation of 49 ± 8% y(-1) for all the cases in 2013. In the other years, the decreasing rates also varied slightly for all cases. These indicated that the decreasing trend of the (137)Cs concentration was nearly unchanged for the location and ground contamination level in the three years after the accident. The (137)Cs activity per aerosol particle mass also decreased with the same trend as the (137)Cs concentration in the atmosphere. The results indicated that the decreasing trend of the atmospheric (137)Cs concentration was related with the reduction of the (137)Cs

  7. MODELING FOR DEMOGRAPHIC AND REGIONAL PREVALENCE AND TRENDS OF SMOKING IN THAI MALES.

    Science.gov (United States)

    Lim, Apiradee; McNeil, Don

    2016-03-01

    This study aimed to describe using national survey data the demographic and regional prevalence and trends of smoking in Thai males during the past 25 years. Data from eight national surveys conducted by the National Statistics Office from 1986 to 2011 were used to examine the prevalence of smoking. Males aged 15 and older were included in this study. Logistic regression was used to model smoking patterns, according to year of survey, age group, urbanization, and Public Health Area (PHA). The prevalence of smoking among males aged 15 years and older in 2011 was 38.4%. Sharply increasing smoking prevalence was found in the 15-24 years-old age group in all surveys. Before survey year 1999, the prevalence of smoking started to level off near retirement age, and subsequently, it leveled off after 40 years of age. The prevalence of smoking in all age groups decreased after 1986 except in the 15-19 years-old age group. Higher prevalence of smoking was found in rural areas. Males from the Northeast and the lower South regions had the highest prevalence. More effective anti-smoking policies should focus on males aged below 25 years to reduce the increasing prevalence of smoking in this group.

  8. Trends in Social Science: The Impact of Computational and Simulative Models

    Science.gov (United States)

    Conte, Rosaria; Paolucci, Mario; Cecconi, Federico

    This paper discusses current progress in the computational social sciences. Specifically, it examines the following questions: Are the computational social sciences exhibiting positive or negative developments? What are the roles of agent-based models and simulation (ABM), network analysis, and other "computational" methods within this dynamic? (Conte, The necessity of intelligent agents in social simulation, Advances in Complex Systems, 3(01n04), 19-38, 2000; Conte 2010; Macy, Annual Review of Sociology, 143-166, 2002). Are there objective indicators of scientific growth that can be applied to different scientific areas, allowing for comparison among them? In this paper, some answers to these questions are presented and discussed. In particular, comparisons among different disciplines in the social and computational sciences are shown, taking into account their respective growth trends in the number of publication citations over the last few decades (culled from Google Scholar). After a short discussion of the methodology adopted, results of keyword-based queries are presented, unveiling some unexpected local impacts of simulation on the takeoff of traditionally poorly productive disciplines.

  9. Can a coupled meteorology–chemistry model reproduce the historical trend in aerosol direct radiative effects over the Northern Hemisphere?

    Science.gov (United States)

    The ability of a coupled meteorology–chemistry model, i.e., Weather Research and Forecast and Community Multiscale Air Quality (WRF-CMAQ), to reproduce the historical trend in aerosol optical depth (AOD) and clear-sky shortwave radiation (SWR) over the Northern Hemisphere h...

  10. Can a coupled meteorology–chemistry model reproduce the historical trend in aerosol direct radiative effects over the Northern Hemisphere?

    Science.gov (United States)

    The ability of a coupled meteorology–chemistry model, i.e., Weather Research and Forecast and Community Multiscale Air Quality (WRF-CMAQ), to reproduce the historical trend in aerosol optical depth (AOD) and clear-sky shortwave radiation (SWR) over the Northern Hemisphere h...

  11. Trends in Modelling, Simulation and Design of Water Hydraulic Systems – Motion Control and Open-Ended Solutions

    DEFF Research Database (Denmark)

    Conrad, Finn

    2006-01-01

    The paper presents and discusses a R&D-view on trends in development and best practise in modelling, simulation and design of both low-pressure and high-pressure tap water hydraulic components and systems for motion control as well as open-ended solutions various industrial applications. The focus...

  12. On the use of a regression model for trend estimates from ground-based atmospheric observations in the Southern hemisphere

    CSIR Research Space (South Africa)

    Bencherif, H

    2010-09-01

    Full Text Available The present reports on the use of a multi-regression model adapted at Reunion University for temperature and ozone trend estimates. Depending on the location of the observing site, the studied geophysical signal is broken down in form of a sum...

  13. Exploration of the Growing Trend of Electric Vehicles in Beijing with System Dynamics method and Vensim model

    NARCIS (Netherlands)

    Zhang, C.; Qin, C.

    2014-01-01

    This research is conducted to explore the growing trend of private vehicles in Beijing, China, in the coming 25 years using the system dynamics (SD) method. The vensim software is used to build the SD model and do simulations. First, the paper introduces the background of the private vehicles in Bei

  14. A hybrid design-based and model-based sampling approach to estimate the temporal trend of spatial means

    NARCIS (Netherlands)

    Brus, D.J.; Gruijter, de J.J.

    2012-01-01

    This paper launches a hybrid sampling approach, entailing a design-based approach in space followed by a model-based approach in time, for estimating temporal trends of spatial means or totals. The underlying space–time process that generated the soil data is only partly described, viz. by a linear

  15. Characterization of a 320-kb region containing the HEXA gene on bovine chromosome 10 and analysis of its association with BSE susceptibility.

    Science.gov (United States)

    Juling, K; Schwarzenbacher, H; Frankenberg, U; Ziegler, U; Groschup, M; Williams, J L; Fries, R

    2008-08-01

    Bovine spongiform encephalopathy (BSE) belongs to a group of neurodegenerative diseases known as transmissible prion diseases. Recently, variants in the promoter region of the prion protein (PRNP) gene have been shown to have a considerable effect on the susceptibility to BSE. However, a previous genome scan revealed other putative BSE-susceptibility loci. Here, we analysed such a region on BTA10, which contains the functional candidate gene HEXA. Three hundred and twenty kilobases that, besides HEXA, also contain ARIH1, BRUNOL6 and PARP6 were characterized and screened for polymorphisms. Genotyping of 38 SNPs in Holstein-Friesian animals from the UK (350 diseased and 270 controls) revealed two intronic SNPs that were associated with BSE incidence, with experiment-wise P-values of 3.5 x 10(-3) and 7.7 x 10(-3) respectively. Both SNPs were in strong linkage disequilibrium and the rare alleles had a protective effect. These alleles were contained in a haplotype dubbed 'UK-protective' that was significantly overrepresented in the controls with a permuted P-value of 2 x 10(-3). An association study in German Holstein animals (73 diseased and 627 controls) revealed an opposite effect of the 'UK-protective' haplotype in this population, i.e. it was overrepresented in the diseased animals, although not significant after correction for multiple testing. These findings indicate a causal variant for BSE susceptibility on BTA10 in linkage disequilibrium with the markers studied. Candidate gene analyses of the surrounding region and additional association studies will help to clarify the origin of the protective effects and to identify causal variants for BSE susceptibility on BTA10.

  16. [Animal-derived feedstuffs as possible vectors for bovine encephalopathy (BSE) in Germany. Part 2: Assessment of vector risk for compounded feed].

    Science.gov (United States)

    Zentek, J; Oberthür, R C; Kamphues, J; Kreienbrock, L; Flachowsky, G; Coenen, M

    2002-02-01

    Specific conditions and practices of cattle feeding in Germany have to be taken into account for assessing the risk of feed born transmission of bovine spongiform encephalopathy, especially regarding the situation before the year 2000 when specific directives were introduced for feed production. The present retrospective epidemiological study includes data on feed production and the estimated amount of animal derived feedstuffs for the production of compounded feed for cattle. Risk assessment was performed based on the 'reproduction rate' (R0), that is defined as the estimated number of infections resulting from the processing of brain and spinal cord of BSE affected cattle that is recycled to bovines via feed. Under the conditions as given in Germany until the year 2000 the reproduction rate of BSE via the inclusion of animal derived feedstuffs in compounded feed production for cattle was estimated to be 1.1. Thus, it can be expected that BSE could be reproduced in the system, but with comparatively low efficiency. The expected incidence of BSE should be considerably lower compared to the situation during the 90th in the UK, due to the markedly lower recycling rate of animal protein in cattle feeding. Animal fat could have been a significant factor for BSE transmission due to contamination by proteinaceous brain and spinal cord material during the production process. The relative significance of fat containing feedstuffs for BSE transmission could have been higher in Germany compared to the situation in the UK where meat and bone meal was produced under different conditions and frequently used in higher proportions as an ingredient for compounded feed for ruminants.

  17. Analysis of the eight-year trend in ozone depletion from empirical models of solar backscattered ultraviolet instrument degradation

    Science.gov (United States)

    Herman, J. R.; Hudson, R. D.; Serafino, G.

    1990-01-01

    Arguments are presented showing that the basic empirical model of the solar backscatter UV (SBUV) instrument degradation used by Cebula et al. (1988) in their analysis of the SBUV data is likely to lead to an incorrect estimate of the ozone trend. A correction factor is given as a function of time and altitude that brings the SBUV data into approximate agreement with the SAGE, SME, and Dobson network ozone trends. It is suggested that the currently archived SBUV ozone data should be used with caution for periods of analysis exceeding 1 yr, since it is likely that the yearly decreases contained in the archived data are too large.

  18. A New Weighting Function for Estimating Microwave Sounding Unit Channel 4 Temperature Trends Simulated by CMIP5 Climate Models

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xuanze; ZHENG Xiaogu; YANG Chi; LUO San

    2013-01-01

    A new static microwave sounding unit (MSU) channel 4 weighting function is obtained from using Coupled Model Inter-comparison Project,Phase 5 (CMIP5) historical multimodel simulations as inputs into the fast Radiative Transfer Model for TOVS (RTTOV vl0).For the same CMIP5 model simulations,it is demonstrated that the computed MSU channel 4 brightness temperature (T4) trends in the lower stratosphere over both the globe and the tropics using the proposed weighting function are equivalent to those calculated by RTTOV,but show more cooling than those computed using the traditional UAH (University of Alabama at Huntsville) or RSS (Remote Sensing Systems in Santa Rosa,California) static weighting functions.The new static weighting function not only reduces the computational cost,but also reveals reasons why trends using a radiative transfer model are different from those using a traditional static weighting function.This study also shows that CMIP5 model simulated T4 trends using the traditional UAH or RSS static weighting functions show less cooling than satellite observations over the globe and the tropics.Although not completely removed,this difference can be reduced using the proposed weighting function to some extent,especially over the tropics.This work aims to explore the reasons for the trend differences and to see to what extent they are related to the inaccurate weighting functions.This would also help distinguish other sources for trend errors and thus better understand the climate change in the lower stratosphere.

  19. Can a coupled meteorology-chemistry model reproduce the historical trend in aerosol direct radiative effects over the Northern Hemisphere?

    Directory of Open Access Journals (Sweden)

    J. Xing

    2015-05-01

    Full Text Available The ability of a coupled meteorology-chemistry model, i.e., WRF-CMAQ, in reproducing the historical trend in AOD and clear-sky short-wave radiation (SWR over the Northern Hemisphere has been evaluated through a comparison of 21 year simulated results with observation-derived records from 1990–2010. Six satellite retrieved AOD products including AVHRR, TOMS, SeaWiFS, MISR, MODIS-terra and -aqua as well as long-term historical records from 11 AERONET sites were used for the comparison of AOD trends. Clear-sky SWR products derived by CERES at both TOA and surface as well as surface SWR data derived from seven SURFRAD sites were used for the comparison of trends in SWR. The model successfully captured increasing AOD trends along with the corresponding increased TOA SWR (upwelling and decreased surface SWR (downwelling in both eastern China and the northern Pacific. The model also captured declining AOD trends along with the corresponding decreased TOA SWR (upwelling and increased surface SWR (downwelling in eastern US, Europe and northern Atlantic for the period of 2000–2010. However, the model underestimated the AOD over regions with substantial natural dust aerosol contributions, such as the Sahara Desert, Arabian Desert, central Atlantic and north Indian Ocean. Estimates of aerosol direct radiative effect (DRE at TOA are comparable with those derived by measurements. Compared to GCMs, the model exhibits better estimates of surface- aerosol direct radiative efficiency (Eτ. However, surface-DRE tends to be underestimated due to the underestimated AOD in land and dust regions. Further investigation of TOA-Eτ estimations as well as the dust module used for estimates of windblown-dust emissions is needed.

  20. How do US and Canadian consumers value credence attributes associated with beef labels after the North American BSE crisis of 2003?

    DEFF Research Database (Denmark)

    Steiner, Bodo; Yang, Jun

    2010-01-01

    A consumer survey conducted in 2006 (n = 419), and therefore after the first confirmed bovine spongiform encephalopathy (BSE) cases in North America in 2003, employs attribute-based choice experiments for a cross-country comparison of consumers' valuation of credence attributes associated with beef...... steak labels; specifically a guarantee that beef was tested for BSE, a guarantee that the steaks were produced without genetically modified organisms (GMOs) and a guarantee that beef steaks were produced without growth hormones and antibiotics. Considering consumers' socio-economic characteristics...

  1. Use of hierarchical models to analyze European trends in congenital anomaly prevalence

    NARCIS (Netherlands)

    Cavadino, Alana; Prieto-Merino, David; Addor, Marie-Claude; Arriola, Larraitz; Bianchi, Fabrizio; Draper, Elizabeth; Garne, Ester; Greenlees, Ruth; Haeusler, Martin; Khoshnood, Babak; Kurinczuk, Jenny; McDonnell, Bob; Nelen, Vera; O'Mahony, Mary; Randrianaivo, Hanitra; Rankin, Judith; Rissmann, Anke; Tucker, David; Verellen-Dumoulin, Christine; de Walle, Hermien; Wellesley, Diana; Morris, Joan K.

    Background: Surveillance of congenital anomalies is important to identify potential Teratcgens. Despite known associations between different anomalies, current surveillance methods examine trends witin each subgroup separately. We aimed to evaluate whether hierarchical statistical methods that

  2. Trend of Smear-positive Pulmonary Tuberculosis in Iran during 1995-2012: A Segmented Regression Model.

    Science.gov (United States)

    Khazaei, Salman; Soheilyzad, Mokhtar; Molaeipoor, Leila; Khazaei, Zaher; Rezaeian, Shahab; Khazaei, Somayeh

    2016-01-01

    Describing trend in tuberculosis (TB) over time can play an important role to assess the disease control strategies and predict the future morbidity and mortality. This study aimed to determine the incidence trend of smear-positive pulmonary tuberculosis (SPPT) in sub-age and sex groups during the years of 1995-2012. This retrospective cohort study was performed in 2015 by using the dataset regarding National Statistics of SPPT reported by World Health Organization during 1995-2012. Annual percent changes (APCs) and average annual percent changes (AAPCs) were estimated to determine the summery statistics of trend using segmented regression model. During 1995-2012, there were 96,579 SPPT case notifications in Iran (male to female ratio: 0.99). There was only one change point in 1997 for SPPT incidence in subgroups of age and sex during 1995-2012. The AAPCs for both genders and also all three age groups had a significant descending trend during the time period (P trend in the SPPT incidence. It seems that to achieve the set goals and high successful in TB control program especially reduction in SPPT, pay more attention to old age and males should be considered. In addition, improvement of clinical and medical care services and notification processes would be imperative.

  3. Grey GM(1,1) Model with Function-Transfer Method for Wear Trend Prediction and its Application

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Trend forecasting is an important aspect in fault diagnosis and work state super-vision. The principle, where Grey theory is applied in fault forecasting, is that the fore-cast system is considered as a Grey system; the existing known information is used to infer the unknown in f ormations character, state and development trend in a fault pattern, and to make possible forecasting and decisions for future development. It involves the whiteniza tion of a Grey process. But the traditional equal time interval Grey GM (1,1) model re-quires equal interval data and needs to bring about accumulating addition generation and reversion calculations. Its calculation is very complex. However, the non-equal interval Grey GM (1,1) model decreases the condition of the primitive data when establishing a model,but its requirement is still higher and the data were pre-processed. The abrasion primitive data of plant could not always satisfy these modeling requirements. Therefore, it establi-shes a division method suited for general data modeling and estimating parameters of GM (1,1), the standard error coefficient that was applied to judge accuracy height of the model was put forward; further, the function transform to forecast plant abrasion trend and assess GM (1,1) parameter was established. These two models need not pre-process the primitive data. It is not only suited for equal interval data modeling, but also for non-e-qual interval data modeling. Its calculation is simple and convenient to use. The oil spec-trum analysis acted as an example. The two GM (1,1) models put forward in this paper and the new information model and its comprehensive usage were investigated. The exam ple shows that the two models are simple and practical, and worth expanding and apply-ing in plant fault diagnosis.

  4. Chandra Observations and Models of the Mixed Morphology Supernova Remnant W44: Global Trends

    Science.gov (United States)

    Shelton, R. L.; Kuntz, K. D.; Petre, R.

    2004-01-01

    We report on the Chandra observations of the archetypical mixed morphology (or thermal composite) supernova remnant, W44. As with other mixed morphology remnants, W44's projected center is bright in thermal X-rays. It has an obvious radio shell, but no discernable X-ray shell. In addition, X-ray bright knots dot W44's image. The spectral analysis of the Chandra data show that the remnant s hot, bright projected center is metal-rich and that the bright knots are regions of comparatively elevated elemental abundances. Neon is among the affected elements, suggesting that ejecta contributes to the abundance trends. Furthermore, some of the emitting iron atoms appear to be underionized with respect to the other ions, providing the first potential X-ray evidence for dust destruction in a supernova remnant. We use the Chandra data to test the following explanations for W44's X-ray bright center: 1.) entropy mixing due to bulk mixing or thermal conduction, 2.) evaporation of swept up clouds, and 3.) a metallicity gradient, possibly due to dust destruction and ejecta enrichment. In these tests, we assume that the remnant has evolved beyond the adiabatic evolutionary stage, which explains the X-ray dimness of the shell. The entropy mixed model spectrum was tested against the Chandra spectrum for the remnant's projected center and found to be a good match. The evaporating clouds model was constrained by the finding that the ionization parameters of the bright knots are similar to those of the surrounding regions. While both the entropy mixed and the evaporating clouds models are known to predict centrally bright X-ray morphologies, their predictions fall short of the observed brightness gradient. The resulting brightness gap can be largely filled in by emission from the extra metals in and near the remnant's projected center. The preponderance of evidence (including that drawn from other studies) suggests that W44's remarkable morphology can be attributed to dust destruction

  5. Transport and Environment Database System (TRENDS): Maritime air pollutant emission modelling

    Science.gov (United States)

    Georgakaki, Aliki; Coffey, Robert A.; Lock, Graham; Sorenson, Spencer C.

    This paper reports the development of the maritime module within the framework of the Transport and Environment Database System (TRENDS) project. A detailed database has been constructed for the calculation of energy consumption and air pollutant emissions. Based on an in-house database of commercial vessels kept at the Technical University of Denmark, relationships between the fuel consumption and size of different vessels have been developed, taking into account the fleet's age and service speed. The technical assumptions and factors incorporated in the database are presented, including changes from findings reported in Methodologies for Estimating air pollutant Emissions from Transport (MEET). The database operates on statistical data provided by Eurostat, which describe vessel and freight movements from and towards EU 15 major ports. Data are at port to Maritime Coastal Area (MCA) level, so a bottom-up approach is used. A port to MCA distance database has also been constructed for the purpose of the study. This was the first attempt to use Eurostat maritime statistics for emission modelling; and the problems encountered, since the statistical data collection was not undertaken with a view to this purpose, are mentioned. Examples of the results obtained by the database are presented. These include detailed air pollutant emission calculations for bulk carriers entering the port of Helsinki, as an example of the database operation, and aggregate results for different types of movements for France. Overall estimates of SO x and NO x emission caused by shipping traffic between the EU 15 countries are in the area of 1 and 1.5 million tonnes, respectively.

  6. EPQ model for imperfect production processes with rework and random preventive machine time for deteriorating items and trended demand

    Directory of Open Access Journals (Sweden)

    Shah Nita H.

    2015-01-01

    Full Text Available Economic production quantity (EPQ model has been analyzed for trended demand, and units in inventory are subject to constant rate. The system allows rework of imperfect units, and preventive maintenance time is random. A search method is used to study the model. The proposed methodology is validated by a numerical example. The sensitivity analysis is carried out to determine the critical model parameters. It is observed that the rate of change of demand, and the deterioration rate have a significant impact on the decision variables and the total cost of an inventory system. The model is highly sensitive to the production and demand rate.

  7. Long-lived halocarbon trends and budgets from atmospheric chemistry modelling constrained with measurements in polar firn

    Directory of Open Access Journals (Sweden)

    P. Martinerie

    2009-01-01

    Full Text Available The budgets of seven halogenated gases (CFC-11, CFC-12, CFC-113, CFC-114, CFC-115, CCl4 and SF6 are studied by comparing measurements in polar firn air from two Arctic and three Antarctic sites, and simulation results of two numerical models: a 2-D atmospheric chemistry model and a 1-D firn diffusion model. The first one is used to calculate atmospheric concentrations from emission trends based on industrial inventories; the calculated concentration trends are used by the second one to produce depth concentration profiles in the firn. The 2-D atmospheric model is validated in the boundary layer by comparison with atmospheric station measurements, and vertically for CFC-12 by comparison with balloon and FTIR measurements. Firn air measurements provide constraints on historical atmospheric concentrations over the last century. Age distributions in the firn are discussed using a Green function approach. Finally, our results are used as input to a radiative model in order to evaluate the radiative forcing of our target gases. Multi-species and multi-site firn air studies allow to better constrain atmospheric trends. The low concentrations of all studied gases at the bottom of the firn, and their consistency with our model results confirm that their natural sources are insignificant. Our results indicate that the emissions, sinks and trends of CFC-11, CFC-12, CFC-113, CFC-115 and SF6 are well constrained, whereas it is not the case for CFC-114 and CCl4. Significant emission-dependent changes in the lifetimes of halocarbons destroyed in the stratosphere were obtained. Those result from the time needed for their transport from the surface where they are emitted to the stratosphere where they are destroyed. Efforts should be made to update and reduce the large uncertainties on CFC lifetimes.

  8. Long-lived halocarbon trends and budgets from atmospheric chemistry modelling constrained with measurements in polar firn

    Directory of Open Access Journals (Sweden)

    P. Martinerie

    2009-06-01

    Full Text Available The budgets of seven halogenated gases (CFC-11, CFC-12, CFC-113, CFC-114, CFC-115, CCl4 and SF6 are studied by comparing measurements in polar firn air from two Arctic and three Antarctic sites, and simulation results of two numerical models: a 2-D atmospheric chemistry model and a 1-D firn diffusion model. The first one is used to calculate atmospheric concentrations from emission trends based on industrial inventories; the calculated concentration trends are used by the second one to produce depth concentration profiles in the firn. The 2-D atmospheric model is validated in the boundary layer by comparison with atmospheric station measurements, and vertically for CFC-12 by comparison with balloon and FTIR measurements. Firn air measurements provide constraints on historical atmospheric concentrations over the last century. Age distributions in the firn are discussed using a Green function approach. Finally, our results are used as input to a radiative model in order to evaluate the radiative forcing of our target gases. Multi-species and multi-site firn air studies allow to better constrain atmospheric trends. The low concentrations of all studied gases at the bottom of the firn, and their consistency with our model results confirm that their natural sources are small. Our results indicate that the emissions, sinks and trends of CFC-11, CFC-12, CFC-113, CFC-115 and SF6 are well constrained, whereas it is not the case for CFC-114 and CCl4. Significant emission-dependent changes in the lifetimes of halocarbons destroyed in the stratosphere were obtained. Those result from the time needed for their transport from the surface where they are emitted to the stratosphere where they are destroyed. Efforts should be made to update and reduce the large uncertainties on CFC lifetimes.

  9. Contribution of H. pylori and smoking trends to US incidence of intestinal-type noncardia gastric adenocarcinoma: a microsimulation model.

    Directory of Open Access Journals (Sweden)

    Jennifer M Yeh

    Full Text Available Although gastric cancer has declined dramatically in the US, the disease remains the second leading cause of cancer mortality worldwide. A better understanding of reasons for the decline can provide important insights into effective preventive strategies. We sought to estimate the contribution of risk factor trends on past and future intestinal-type noncardia gastric adenocarcinoma (NCGA incidence.We developed a population-based microsimulation model of intestinal-type NCGA and calibrated it to US epidemiologic data on precancerous lesions and cancer. The model explicitly incorporated the impact of Helicobacter pylori and smoking on disease natural history, for which birth cohort-specific trends were derived from the National Health and Nutrition Examination Survey (NHANES and National Health Interview Survey (NHIS. Between 1978 and 2008, the model estimated that intestinal-type NCGA incidence declined 60% from 11.0 to 4.4 per 100,000 men, <3% discrepancy from national statistics. H. pylori and smoking trends combined accounted for 47% (range = 30%-58% of the observed decline. With no tobacco control, incidence would have declined only 56%, suggesting that lower smoking initiation and higher cessation rates observed after the 1960s accelerated the relative decline in cancer incidence by 7% (range = 0%-21%. With continued risk factor trends, incidence is projected to decline an additional 47% between 2008 and 2040, the majority of which will be attributable to H. pylori and smoking (81%; range = 61%-100%. Limitations include assuming all other risk factors influenced gastric carcinogenesis as one factor and restricting the analysis to men.Trends in modifiable risk factors explain a significant proportion of the decline of intestinal-type NCGA incidence in the US, and are projected to continue. Although past tobacco control efforts have hastened the decline, full benefits will take decades to be realized, and further discouragement of smoking and

  10. a Model Analysis of the Spatial Distribution and Temporal Trends of Nitrous Oxide Sources and Sinks

    Science.gov (United States)

    Nevison, Cynthia Dale

    1994-01-01

    Nitrous oxide ({N_ {2}O}), an atmospheric trace gas that contributes to both greenhouse warming and stratospheric ozone depletion, is increasing at an annual rate of about 0.25%/yr. By use of a global model of the changing terrestrial nitrogen cycle, the timing and magnitude of this increase are shown to be consistent with enhanced microbial N _2O production due to fertilizer, land clearing, livestock manure, and human sewage. Fertilizer appears to be a particularly important source. Increasing emissions from additional anthropogenic N_2O sources, including fossil fuel combustion and nylon production are also shown to coincide with and contribute to N _2O's annual atmospheric increase. Collectively, these industrial, combustion-related, and enhanced microbial N_2O emissions add up to a total anthropogenic source of about 5 Tg N/yr. Natural N_2O emissions from microbial activity in soils and oceans and from natural fires are estimated to produce an annual source of about 11 Tg N/yr, of which the oceans contribute a substantially larger fraction than reported in most current budgets. In contrast to anthropogenic emissions, which are increasing rapidly, natural emissions are predicted to remain relatively constant from 1860 to 2050, although this prediction ignores possible enhancements in microbial N_2O production due to global warming. Also in contrast to anthropogenic emissions, which are heavily dominated by the northern hemisphere, the natural source is fairly evenly distributed over the Earth. The predicted magnitude of the natural source is checked against an estimate of the N_2O stratospheric sink, while the predicted present day distribution of natural and anthropogenic sources is tested in a 3-dimensional transport model run. This run reproduces the observed 1ppb interhemispheric gradient (higher in the north), and suggests that larger gradients may exist over strong continental source regions. Substantial increases in most anthropogenic N _2O sources are

  11. Emerging trends in cancer care: health plans' and pharmacy benefit managers' perspectives on changing care models.

    Science.gov (United States)

    Greenapple, Rhonda

    2012-07-01

    % of the plans. The use of the National Comprehensive Cancer Network practice guidelines for coverage and reimbursement of oncologic agents is reported as "very frequent" by 10% of survey respondents, "frequent" by 21%, and "moderately frequent" by 7%. Most (66%) respondents believe that it is probable and 3% believe it is highly probable that healthcare reform will help to control oncology treatment costs, although 59% also predict an increase in utilization restrictions and 48% predict more stringent comparative effectiveness evidence requirements. The survey reveals a considerable uncertainty among health plans and PBMs about the eventual impact of ACOs on oncology care. Although 82% of those surveyed believe that measures such as increasing adherence to evidence-based treatments will achieve cost-savings, nearly half (48%) had no plans to use such measures. Recent trends in healthcare legislation, rising drug costs, and changing reimbursement practices are poised to significantly alter conventional models of cancer care delivery and payment. The results of this survey indicate that health plans and PBMs anticipate greater use of evidence-based management strategies, including CER, quality initiatives, and biomarker testing for appropriate cancer therapy selection. In addition, they anticipate greater focus on cost control, with a greater role for utilization management and increased patient cost-sharing. Finally, there is a high level of uncertainty among plans and PBMs about the eventual impact of ACOs and other aspects of healthcare reform on oncology practice.

  12. Mismatch between observed and modeled trends in dissolved upper-ocean oxygen over the last 50 yr

    Directory of Open Access Journals (Sweden)

    L. Stramma

    2012-10-01

    Full Text Available Observations and model runs indicate trends in dissolved oxygen (DO associated with current and ongoing global warming. However, a large-scale observation-to-model comparison has been missing and is presented here. This study presents a first global compilation of DO measurements covering the last 50 yr. It shows declining upper-ocean DO levels in many regions, especially the tropical oceans, whereas areas with increasing trends are found in the subtropics and in some subpolar regions. For the Atlantic Ocean south of 20° N, the DO history could even be extended back to about 70 yr, showing decreasing DO in the subtropical South Atlantic. The global mean DO trend between 50° S and 50° N at 300 dbar for the period 1960 to 2010 is –0.066 μmol kg−1 yr−1. Results of a numerical biogeochemical Earth system model reveal that the magnitude of the observed change is consistent with CO2-induced climate change. However, the pattern correlation between simulated and observed patterns of past DO change is negative, indicating that the model does not correctly reproduce the processes responsible for observed regional oxygen changes in the past 50 yr. A negative pattern correlation is also obtained for model configurations with particularly low and particularly high diapycnal mixing, for a configuration that assumes a CO2-induced enhancement of the C : N ratios of exported organic matter and irrespective of whether climatological or realistic winds from reanalysis products are used to force the model. Depending on the model configuration the 300 dbar DO trend between 50° S and 50° N is −0.027 to –0.047 μmol kg−1 yr−1 for climatological wind forcing, with a much larger range of –0.083 to +0.027 μmol kg−1 yr−1 for different initializations of sensitivity runs with reanalysis wind forcing. Although numerical models reproduce the overall sign and, to

  13. THE EFFECT OF DECOMPOSITION METHOD AS DATA PREPROCESSING ON NEURAL NETWORKS MODEL FOR FORECASTING TREND AND SEASONAL TIME SERIES

    Directory of Open Access Journals (Sweden)

    Subanar Subanar

    2006-01-01

    Full Text Available Recently, one of the central topics for the neural networks (NN community is the issue of data preprocessing on the use of NN. In this paper, we will investigate this topic particularly on the effect of Decomposition method as data processing and the use of NN for modeling effectively time series with both trend and seasonal patterns. Limited empirical studies on seasonal time series forecasting with neural networks show that some find neural networks are able to model seasonality directly and prior deseasonalization is not necessary, and others conclude just the opposite. In this research, we study particularly on the effectiveness of data preprocessing, including detrending and deseasonalization by applying Decomposition method on NN modeling and forecasting performance. We use two kinds of data, simulation and real data. Simulation data are examined on multiplicative of trend and seasonality patterns. The results are compared to those obtained from the classical time series model. Our result shows that a combination of detrending and deseasonalization by applying Decomposition method is the effective data preprocessing on the use of NN for forecasting trend and seasonal time series.

  14. Population trends of grassland birds in North America are linked to the prevalence of an agricultural epizootic in Europe.

    Science.gov (United States)

    Nocera, Joseph J; Koslowsky, Hannah M

    2011-03-22

    Globalization of trade has dramatic socioeconomic effects, and, intuitively, significant ecological effects should follow. However, few quantitative examples exist of the interrelationship of globalization, socioeconomics, and ecological patterns. We present a striking illustration of a cascade in which bovine spongiform encephalopathy (BSE; "mad cow disease") outbreaks in Europe exerted pressure on global beef markets, subsequently affecting North American hayfields and grassland bird populations. We examined competing models, which linked the prevalence of BSE in five focal countries, volume of beef exports to those countries from North America, and the amount of hayfield harvested and the abundance of grassland birds in North America. We found that (i) imports from North America increased 1 y after BSE outbreaks; (ii) probably because fewer cattle remained, the hay harvest in North America was reduced 2 y after the outbreak; (iii) the reduced hay harvest yielded a positive response in grassland bird populations 3 y after the outbreak.

  15. Assessing the trend of HIV/AIDS mortality rate in Asia and North Africa: an application of latent growth models.

    Science.gov (United States)

    Zayeri, F; Talebi Ghane, E; Borumandnia, N

    2016-02-01

    Over the last 30 years, HIV/AIDS has emerged as a major global health challenge. This study evaluates the change of HIV/AIDS mortality rates in Asian and North African countries from 1990 to 2010 using the Global Burden of Disease (GBD) study. HIV/AIDS mortality rates were derived from the GBD database from 1990 to 2010, for 52 countries in Asia and North Africa. First, a Latent Growth Model was employed to assess the change in AIDS mortality rate over time in six different regions of Asia, and also the change in AIDS mortality rate over time for males and females in Asia and North Africa. Finally, Latent Growth Mixture Models (LGMMs) were applied to identify distinct groups in which countries within each group have similar trends over time. Our results showed that increase in mortality rate over time for males is about three times greater than for females. The highest and lowest trend of AIDS mortality rates were observed in South-East Asia and high-income Asia-Pacific regions, respectively. The LGMM allocated most countries in the South and South-East region into two classes with the highest trend of AIDS mortality rates. Although the HIV/AIDS mortality rates are decreasing in some countries and clusters, the general trend in the Asian continent is upwards. Therefore, it is necessary to provide programmes to achieve the goal of access to HIV prevention measures, treatment, care, and support for high-risk groups, especially in countries with a higher trend of AIDS mortality rates.

  16. Evaluation of the effectiveness of selected measures against Bovine Spongiform Encephalopathy (BSE) in Switzerland by use of the basic reproduction ratio R0

    NARCIS (Netherlands)

    Schwermer, H.; Brülisauer, F.; Koeijer, de A.A.; Heim, D.

    2007-01-01

    The effectiveness of two measures against Bovine Spongiform Encephalopathy (BSE), the compulsory processing of animal by products to meat and bone mea (MBM) at 133 °C under 3 bars of pressure for 20 minutes in February 1993 and the exclusion offallen stock, heads with eyes and spinal cord of cattle

  17. How do US and Canadian consumers value credence attributes associated with beef labels after the North American BSE crisis of 2003?

    DEFF Research Database (Denmark)

    Steiner, Bodo; Yang, Jun

    2010-01-01

    A consumer survey conducted in 2006 (n = 419), and therefore after the first confirmed bovine spongiform encephalopathy (BSE) cases in North America in 2003, employs attribute-based choice experiments for a cross-country comparison of consumers' valuation of credence attributes associated with be...

  18. Chronic wasting disease and atypical forms of BSE and scrapie are not transmissible to mice expressing wild-type levels of human PrP

    Science.gov (United States)

    The association between bovine spongiform encephalopathy (BSE) and variant Creutzfeldt-Jakob disease (vCJD) has demonstrated that cattle TSEs can pose a risk to human health and raises the possibility that other ruminant TSEs may be transmissible to humans. In recent years, several new TSEs in shee...

  19. EURODELTA-Trends, a multi-model experiment of air quality hindcast in Europe over 1990–2010

    Directory of Open Access Journals (Sweden)

    A. Colette

    2017-09-01

    Full Text Available The EURODELTA-Trends multi-model chemistry-transport experiment has been designed to facilitate a better understanding of the evolution of air pollution and its drivers for the period 1990–2010 in Europe. The main objective of the experiment is to assess the efficiency of air pollutant emissions mitigation measures in improving regional-scale air quality. The present paper formulates the main scientific questions and policy issues being addressed by the EURODELTA-Trends modelling experiment with an emphasis on how the design and technical features of the modelling experiment answer these questions. The experiment is designed in three tiers, with increasing degrees of computational demand in order to facilitate the participation of as many modelling teams as possible. The basic experiment consists of simulations for the years 1990, 2000, and 2010. Sensitivity analysis for the same three years using various combinations of (i anthropogenic emissions, (ii chemical boundary conditions, and (iii meteorology complements it. The most demanding tier consists of two complete time series from 1990 to 2010, simulated using either time-varying emissions for corresponding years or constant emissions. Eight chemistry-transport models have contributed with calculation results to at least one experiment tier, and five models have – to date – completed the full set of simulations (and 21-year trend calculations have been performed by four models. The modelling results are publicly available for further use by the scientific community. The main expected outcomes are (i an evaluation of the models' performances for the three reference years, (ii an evaluation of the skill of the models in capturing observed air pollution trends for the 1990–2010 time period, (iii attribution analyses of the respective role of driving factors (e.g. emissions, boundary conditions, meteorology, (iv a dataset based on a multi-model approach, to provide more robust model

  20. Evaluation of Thompson-type trend and monthly weather data models for corn yields in Iowa, Illinois, and Indiana

    Science.gov (United States)

    French, V. (Principal Investigator)

    1982-01-01

    An evaluation was made of Thompson-Type models which use trend terms (as a surrogate for technology), meteorological variables based on monthly average temperature, and total precipitation to forecast and estimate corn yields in Iowa, Illinois, and Indiana. Pooled and unpooled Thompson-type models were compared. Neither was found to be consistently superior to the other. Yield reliability indicators show that the models are of limited use for large area yield estimation. The models are objective and consistent with scientific knowledge. Timely yield forecasts and estimates can be made during the growing season by using normals or long range weather forecasts. The models are not costly to operate and are easy to use and understand. The model standard errors of prediction do not provide a useful current measure of modeled yield reliability.

  1. Trends in carbon stocks in Dutch soils: datasets and modeling results

    NARCIS (Netherlands)

    Chardon, W.J.; Heesmans, H.I.M.; Kuikman, P.J.

    2009-01-01

    Observations on trends in soil organic carbon (SOC) in agricultural soils is an important basis for mandatory reporting of emission of greenhouse gases from land use. A decrease indicates that these soils are a source of CO2, an increase that they are a sink. IPCC Good Practice Guidance generally

  2. Monolith ERP and current IT-trends : Creating a step by step development model (SSDM) for existing monolith ERP system to adapt to the current IT-trends

    OpenAIRE

    Vuorenmaa, Riku

    2015-01-01

    ERP systems have been around for 25 years and have gone through evolution phases. None of the previous phases have however imposed so big a challenge and opportunities for the ERP producers / vendors as current outsourcing and cloud computing trends. Current traditional on-premises (monolith) ERP systems are put under pressure to cope with the demands imposed by cloud computing and other IT-trends (such as mobility). Traditional ERP systems have to adapt or face a risk of becoming obsolete. ...

  3. Factors related to the practice of breast self examination (BSE and Pap smear screening among Malaysian women workers in selected electronics factories

    Directory of Open Access Journals (Sweden)

    Shamsuddin K

    2003-05-01

    Full Text Available Abstract Background The Malaysian Ministry of Health promotes breast self-examination (BSE for all women, and Pap smear screening every three years for all sexually active women ages 20 years and above. The objectives of this paper were to examine the practice of these two screening tests among women production workers in electronics factories, and to identify factors related to practice. Methods This was a cross-sectional survey of women production workers from ten electronics factories. Data was collected by a self-administered questionnaire from a total of 1,720 women. The chi-square test, odds ratio and binomial logistic regression were used in bivariate and multivariate analysis. Results Prevalence rates were 24.4% for BSE once a month, and 18.4% for Pap smear examination within the last three years. Women who were significantly more likely to perform BSE every month were 30 years and older, Malays, with upper secondary education and above, answered the BSE question correctly, and had a Pap smear within the last three years. The proportion of women who had a Pap smear within the last three years were significantly higher among those who were older, married, with young children, on the contraceptive pill or intra-uterine device, had a medical examination within the last five years, answered the Pap smear question correctly, and performed BSE monthly. Conclusion Screening practice rates in this study were low when compared to national rates. Socio-demographic and health care factors significantly associated with screening practice are indicative of barriers which should be further understood so that more effective educational and promotional strategies could be developed.

  4. Driving forces behind the increasing cardiovascular treatment intensity.A dynamic epidemiologic model of trends in Danish cardiovascular drug utilization.

    DEFF Research Database (Denmark)

    Kildemoes, Helle Wallach; Andersen, Morten

    -state (untreated, treated, dead) semi-Markov model to analyse the dynamics of drug use. Transitions were from untreated to treated (incidence), the reverse (discontinuation), and from either untreated or treated to dead. Stratified by sex and age categories, prevalence trends of "growth driving" drug categories...... were analysed, exploring trends in incidence- mortality- and discontinuation rates. Trends in prevalence proportions were estimated from logistic regression. Incidence-, discontinuation and mortality rates from Poisson regression. Results: The total cardiovascular treatment intensity increased from 285...

  5. A semiparametric joint model for terminal trend of quality of life and survival in palliative care research.

    Science.gov (United States)

    Li, Zhigang; Frost, H R; Tosteson, Tor D; Zhao, Lihui; Liu, Lei; Lyons, Kathleen; Chen, Huaihou; Cole, Bernard; Currow, David; Bakitas, Marie

    2017-08-17

    Palliative medicine is an interdisciplinary specialty focusing on improving quality of life (QOL) for patients with serious illness and their families. Palliative care programs are available or under development at over 80% of large US hospitals (300+ beds). Palliative care clinical trials present unique analytic challenges relative to evaluating the palliative care treatment efficacy which is to improve patients' diminishing QOL as disease progresses towards end of life (EOL). A unique feature of palliative care clinical trials is that patients will experience decreasing QOL during the trial despite potentially beneficial treatment. Often longitudinal QOL and survival data are highly correlated which, in the face of censoring, makes it challenging to properly analyze and interpret terminal QOL trend. To address these issues, we propose a novel semiparametric statistical approach to jointly model the terminal trend of QOL and survival data. There are two sub-models in our approach: a semiparametric mixed effects model for longitudinal QOL and a Cox model for survival. We use regression splines method to estimate the nonparametric curves and AIC to select knots. We assess the model performance through simulation to establish a novel modeling approach that could be used in future palliative care research trials. Application of our approach in a recently completed palliative care clinical trial is also presented. Copyright © 2017 John Wiley & Sons, Ltd.

  6. Use of hierarchical models to analyze European trends in congenital anomaly prevalence

    DEFF Research Database (Denmark)

    Cavadino, Alana; Prieto-Merino, David; Addor, Marie-Claude

    2016-01-01

    BACKGROUND: Surveillance of congenital anomalies is important to identify potential teratogens. Despite known associations between different anomalies, current surveillance methods examine trends within each subgroup separately. We aimed to evaluate whether hierarchical statistical methods that c...... in relation to the prevalence of congenital anomalies, which could be investigated in other studies. Birth Defects Research (Part A) 106:480-10, 2016. © 2016 Wiley Periodicals, Inc....

  7. Incorporating a trend analysis of large flow perturbations into stochastic modeling of particle transport in open channel flow

    Science.gov (United States)

    Tsai, Christina W.; Lin, Emily Y.; Hung, Serena Y.

    2016-10-01

    In extreme flow conditions, both the flow carrying capacity and movement of particles may abruptly change from those associated with regular flows. This study investigates movement of sediment particles in response to extreme flow events using a Lagrangian stochastic jump diffusion particle tracking model (SJD-PTM). The study attempts to investigate the frequency change of extreme flow event occurrences and its impact on suspended sediment particle movement. Using the concept of logistic regression, the trend magnitude of extreme flow events can be used as an input of the proposed stochastic jump diffusion particle tracking model with Logistic regression (SJ-PTM_LR) to account for the potential effects of environmental change. The predicted frequency change of extreme flows from available data in the Chijiawan region in central Taiwan is illustrated in this study. Both ensemble mean and variance of particle trajectory can be quantified under such predicted frequency trend change of extreme flow occurrences via simulations of SJ-PTM_LR. Results show that particle movement uncertainty may undergo a significant increase by taking the effect of the predicted flow frequency trend into consideration. Such probabilistic outcome provides a valuable means for assessing the probability of failure (i.e., risk) resulting from sedimentation processes.

  8. Brewer–Dobson Circulation: Recent-Past and Near-Future Trends Simulated by Chemistry-Climate Models

    Directory of Open Access Journals (Sweden)

    Dingzhu Hu

    2017-01-01

    Full Text Available Based on data from 16 chemistry-climate models (CCMs and separate experimental results using a state-of-the-art CCM, the trends in the Brewer–Dobson circulation (BDC during the second half of the 20th century (1960–2000 and the first half of the 21st century (2001–2050 are examined. From the ensemble mean of the CCMs, the BDC exhibits strengthening trends in both the 20th and 21st centuries; however, the acceleration rates of tropical upwelling and southern downwelling during 2001–2050 are smaller than those during 1960–2000, while the acceleration rate of the northern downward branch of the BDC during 2001–2050 is slightly larger than that during 1960–2000. The differences in the extratropical downwelling trends between the two periods are closely related to changes in planetary-wave propagation into the stratosphere caused by the combined effects of increases in the concentrations of greenhouse gases (GHGs and changes in stratospheric ozone. Model simulations demonstrate that the response of southern downwelling to stratospheric ozone depletion is larger than that to the increase in GHGs, but that the latter plays a more important role in the strengthening of northern downwelling. This result suggests that, under the expected future climate, northern downwelling will play a more important role in balancing tropical upwelling.

  9. On the duality between long-run relations and common trends in the I(1) versus I(2) model

    DEFF Research Database (Denmark)

    Juselius, Katarina

    1994-01-01

    Long-run relations and common trends are discussed in terms of the multivariate cointegration model given in the autoregressive and the moving average form. The basic results needed for the analysis of I(1) and 1(2)processes are reviewed and the results applied to Danish monetary data. The test p......, "excess money" is estimated and its effect on the other determinants of the system is investigated. In particular, it is found that "excess money" has no effect on price inflation...... procedures reveal that nominal money stock is essentially I(2). Long-run price homogeneity is supported by the data and imposed on the system. It is found that the bond rate is weakly exogenous for the long-run parameters and therefore act as a driving trend. Using the nonstationarity property of the data...

  10. Contribution and Trend to Quality Research—a literature review of SERVQUAL model from 1998 to 2013

    Directory of Open Access Journals (Sweden)

    Ya Lan WANG

    2015-01-01

    Full Text Available While many past studies focus on service quality research, especially using the “SERVQUAL”, little is known about the mechanics of this model. Motivated by the need to gauge the contribution of the SERVQUAL model, this study reviews 367 SSCI and SCI articles that are related to the SERVQUAL model from 1998 to 2013. We identify key factors and conduct a survey to search for related articles in the Institute for Scientific Information (ISI Web of Science (WOS database. Research contributions are measured, ranked, and presented based on quantity and quality metrics. The trends of SERVQUAL model research from our results are discussed. This study shows that the SERVQUAL model was one of the hot research topics by academic re-searchers and significantly contributed to service quality research.

  11. Determinants of breast self-examination performance among Iranian women: an application of the health belief model.

    Science.gov (United States)

    Noroozi, Azita; Jomand, Tayyebh; Tahmasebi, Rahim

    2011-06-01

    Breast cancer is one of the most common cancers among women. Screening behavior rates are low in the world. Therefore, the purpose of the current study was to investigate breast self-examination (BSE) rate and the relationships of Health Belief Model (HBM) constructs for predicting BSE. Path analysis was used to examine both one-way direct and indirect effects of HBM factors on BSE in this population (N = 382). Data were collected by a part of Champion's HBM Scale (CHBMS) and a self-administered questionnaire. The results showed that 7.6% of the participants reported performing BSE regularly. The final model provided a good fit to the data, with 13 variables explaining 62% of the variance in BSE. Perceived self-efficacy was intermediate construct between modifying factors and HBM constructs. Also, perceived self-efficacy and perceived benefits were the most highly related to BSE. The results suggest that HBM is a useful framework for identifying factors influencing the use of BSE in Iranian women.

  12. A partial exponential lumped parameter model to evaluate groundwater age distributions and nitrate trends in long-screened wells

    Science.gov (United States)

    Jurgens, Bryant; Bohlke, John Karl; Kauffman, Leon J.; Belitz, Kenneth; Esser, Bradley K.

    2016-01-01

    A partial exponential lumped parameter model (PEM) was derived to determine age distributions and nitrate trends in long-screened production wells. The PEM can simulate age distributions for wells screened over any finite interval of an aquifer that has an exponential distribution of age with depth. The PEM has 3 parameters – the ratio of saturated thickness to the top and bottom of the screen and mean age, but these can be reduced to 1 parameter (mean age) by using well construction information and estimates of the saturated thickness. The PEM was tested with data from 30 production wells in a heterogeneous alluvial fan aquifer in California, USA. Well construction data were used to guide parameterization of a PEM for each well and mean age was calibrated to measured environmental tracer data (3H, 3He, CFC-113, and 14C). Results were compared to age distributions generated for individual wells using advective particle tracking models (PTMs). Age distributions from PTMs were more complex than PEM distributions, but PEMs provided better fits to tracer data, partly because the PTMs did not simulate 14C accurately in wells that captured varying amounts of old groundwater recharged at lower rates prior to groundwater development and irrigation. Nitrate trends were simulated independently of the calibration process and the PEM provided good fits for at least 11 of 24 wells. This work shows that the PEM, and lumped parameter models (LPMs) in general, can often identify critical features of the age distributions in wells that are needed to explain observed tracer data and nonpoint source contaminant trends, even in systems where aquifer heterogeneity and water-use complicate distributions of age. While accurate PTMs are preferable for understanding and predicting aquifer-scale responses to water use and contaminant transport, LPMs can be sensitive to local conditions near individual wells that may be inaccurately represented or missing in an aquifer-scale flow model.

  13. A partial exponential lumped parameter model to evaluate groundwater age distributions and nitrate trends in long-screened wells

    Science.gov (United States)

    Jurgens, Bryant C.; Böhlke, J. K.; Kauffman, Leon J.; Belitz, Kenneth; Esser, Bradley K.

    2016-12-01

    A partial exponential lumped parameter model (PEM) was derived to determine age distributions and nitrate trends in long-screened production wells. The PEM can simulate age distributions for wells screened over any finite interval of an aquifer that has an exponential distribution of age with depth. The PEM has 3 parameters - the ratio of saturated thickness to the top and bottom of the screen and mean age, but these can be reduced to 1 parameter (mean age) by using well construction information and estimates of the saturated thickness. The PEM was tested with data from 30 production wells in a heterogeneous alluvial fan aquifer in California, USA. Well construction data were used to guide parameterization of a PEM for each well and mean age was calibrated to measured environmental tracer data (3H, 3He, CFC-113, and 14C). Results were compared to age distributions generated for individual wells using advective particle tracking models (PTMs). Age distributions from PTMs were more complex than PEM distributions, but PEMs provided better fits to tracer data, partly because the PTMs did not simulate 14C accurately in wells that captured varying amounts of old groundwater recharged at lower rates prior to groundwater development and irrigation. Nitrate trends were simulated independently of the calibration process and the PEM provided good fits for at least 11 of 24 wells. This work shows that the PEM, and lumped parameter models (LPMs) in general, can often identify critical features of the age distributions in wells that are needed to explain observed tracer data and nonpoint source contaminant trends, even in systems where aquifer heterogeneity and water-use complicate distributions of age. While accurate PTMs are preferable for understanding and predicting aquifer-scale responses to water use and contaminant transport, LPMs can be sensitive to local conditions near individual wells that may be inaccurately represented or missing in an aquifer-scale flow model.

  14. Transport and Environment Database System (TRENDS): Maritime Air Pollutant Emission Modelling

    DEFF Research Database (Denmark)

    Georgakaki, Aliki; Coffey, R. A.; Lock, G.

    2003-01-01

    encountered since the statistical data collection was not undertaken with a view to this purpose are mentioned. Examples of the results obtained by the database are presented. These include detailed air pollutant emission results per port and vessel type, to aggregate results for different types of movements......This paper reports the development of the maritime module within the framework of the TRENDS project. A detailed database has been constructed, which includes all stages of the energy consumption and air pollutant emission calculations. The technical assumptions and factors incorporated...... ¿ short sea or deep-sea shipping. Key Words: Air Pollution, Maritime Transport, Air Pollutant Emissions...

  15. Seasonality and Trend Forecasting of Tuberculosis Prevalence Data in Eastern Cape, South Africa, Using a Hybrid Model

    Directory of Open Access Journals (Sweden)

    Adeboye Azeez

    2016-07-01

    Full Text Available Background: Tuberculosis (TB is a deadly infectious disease caused by Mycobacteria tuberculosis. Tuberculosis as a chronic and highly infectious disease is prevalent in almost every part of the globe. More than 95% of TB mortality occurs in low/middle income countries. In 2014, approximately 10 million people were diagnosed with active TB and two million died from the disease. In this study, our aim is to compare the predictive powers of the seasonal autoregressive integrated moving average (SARIMA and neural network auto-regression (SARIMA-NNAR models of TB incidence and analyse its seasonality in South Africa. Methods: TB incidence cases data from January 2010 to December 2015 were extracted from the Eastern Cape Health facility report of the electronic Tuberculosis Register (ERT.Net. A SARIMA model and a combined model of SARIMA model and a neural network auto-regression (SARIMA-NNAR model were used in analysing and predicting the TB data from 2010 to 2015. Simulation performance parameters of mean square error (MSE, root mean square error (RMSE, mean absolute error (MAE, mean percent error (MPE, mean absolute scaled error (MASE and mean absolute percentage error (MAPE were applied to assess the better performance of prediction between the models. Results: Though practically, both models could predict TB incidence, the combined model displayed better performance. For the combined model, the Akaike information criterion (AIC, second-order AIC (AICc and Bayesian information criterion (BIC are 288.56, 308.31 and 299.09 respectively, which were lower than the SARIMA model with corresponding values of 329.02, 327.20 and 341.99, respectively. The seasonality trend of TB incidence was forecast to have a slightly increased seasonal TB incidence trend from the SARIMA-NNAR model compared to the single model. Conclusions: The combined model indicated a better TB incidence forecasting with a lower AICc. The model also indicates the need for resolute

  16. Seasonality and Trend Forecasting of Tuberculosis Prevalence Data in Eastern Cape, South Africa, Using a Hybrid Model.

    Science.gov (United States)

    Azeez, Adeboye; Obaromi, Davies; Odeyemi, Akinwumi; Ndege, James; Muntabayi, Ruffin

    2016-07-26

    Tuberculosis (TB) is a deadly infectious disease caused by Mycobacteria tuberculosis. Tuberculosis as a chronic and highly infectious disease is prevalent in almost every part of the globe. More than 95% of TB mortality occurs in low/middle income countries. In 2014, approximately 10 million people were diagnosed with active TB and two million died from the disease. In this study, our aim is to compare the predictive powers of the seasonal autoregressive integrated moving average (SARIMA) and neural network auto-regression (SARIMA-NNAR) models of TB incidence and analyse its seasonality in South Africa. TB incidence cases data from January 2010 to December 2015 were extracted from the Eastern Cape Health facility report of the electronic Tuberculosis Register (ERT.Net). A SARIMA model and a combined model of SARIMA model and a neural network auto-regression (SARIMA-NNAR) model were used in analysing and predicting the TB data from 2010 to 2015. Simulation performance parameters of mean square error (MSE), root mean square error (RMSE), mean absolute error (MAE), mean percent error (MPE), mean absolute scaled error (MASE) and mean absolute percentage error (MAPE) were applied to assess the better performance of prediction between the models. Though practically, both models could predict TB incidence, the combined model displayed better performance. For the combined model, the Akaike information criterion (AIC), second-order AIC (AICc) and Bayesian information criterion (BIC) are 288.56, 308.31 and 299.09 respectively, which were lower than the SARIMA model with corresponding values of 329.02, 327.20 and 341.99, respectively. The seasonality trend of TB incidence was forecast to have a slightly increased seasonal TB incidence trend from the SARIMA-NNAR model compared to the single model. The combined model indicated a better TB incidence forecasting with a lower AICc. The model also indicates the need for resolute intervention to reduce infectious disease

  17. Trends in world LNG supply through 2030. A model-based analysis; Entwicklung des weltweiten LNG-Angebots bis 2030. Eine modellgestuetzte Analyse

    Energy Technology Data Exchange (ETDEWEB)

    Seeliger, A. [Trianel European Energy Trading GmbH, Aachen (Germany)

    2006-07-01

    The contribution presents selected findings of the LNG supply model MAGELAN. It investigates the trends in the gas market through 2030 and the share of marine transport of LNG by tanker vessels. (orig.)

  18. A modeling study on the role of local SST warming on the precipitation trends observed in north Japan during winter monsoon

    Science.gov (United States)

    Sato, T.; Sugimoto, S.

    2013-12-01

    The role of sea surface temperature (SST) anomaly in modulating the terrestrial precipitation in winter around Japan was investigated using a regional atmospheric model. The terrestrial precipitation over the Japan Sea side (JSS) region in northern Japan was sensitive to the offshore SST anomaly through affecting moisture flux toward Japan. Since the offshore SST was clearly warmer in the 2000s relative to the 1980s, the effect of the long-term SST variation on the terrestrial precipitation trend was examined. The experiment with realistic SST simulated the observed trend in terrestrial precipitation in the JSS region. In contrast, the precipitation trend was significantly reduced in the experiment with climatology SST. Therefore, the long-term SST trend is an important factor for the precipitation trend in the region of Japan and the adjacent oceans where SST has significant trends. Precipitation in the Pacific Ocean side of Japan indicated a weak increasing trend even without the SST trend. This suggests that the long-term variations in extra-tropical cyclones are also an important factor for precipitation trends around the Kuroshio extension.

  19. Monitoring and Modelling the Trends of Primary and Secondary Air Pollution Precursors: The Case of the State of Kuwait

    Directory of Open Access Journals (Sweden)

    S. M. Al-Salem

    2010-01-01

    Full Text Available Since the beginning of the industrial revolution, processes of different scales have contributed greatly to the pollution and waste load on the environment. More specifically, airborne pollutants associated with chemical processes have contributed greatly on the ecosystem and populations health. In this communication, we review recent activities and trends of primary and secondary air pollutants in the state of Kuwait, a country associated with petroleum, petrochemical, and other industrial pollution. Trends of pollutants and impact on human health have been studied and categorized based on recent literature. More attention was paid to areas known to researchers as either precursor sensitive (i.e., nitrogen oxides (NOx, volatile organic compounds (VOCs or adjacent to upstream- or downstream-related activities. Environmental monitoring and modelling techniques relevant to this study are also reviewed. Two case studies that link recent data with models associated with industrial sectors are also demonstrated, focusing mainly on chemical mass balance (CMB and Gaussian line source modelling. It is concluded that a number of the monitoring stations and regulations placed by the Kuwait Environment Public Authority (KUEPA need up-to-date revisions and better network placement, in agreement with previous findings.

  20. Transport and Environment Database System (TRENDS): Maritime Air Pollutant Emission Modelling

    DEFF Research Database (Denmark)

    Georgakaki, Aliki; Coffey, Robert; Lock, Grahm

    2005-01-01

    with a view to this purpose, are mentioned. Examples of the results obtained by the database are presented. These include detailed air pollutant emission calculations for bulk carriers entering the port of Helsinki, as an example of the database operation, and aggregate results for different types......This paper reports the development of the maritime module within the framework of the Transport and Environment Database System (TRENDS) project. A detailed database has been constructed for the calculation of energy consumption and air pollutant emissions. Based on an in-house database...... changes from findings reported in Methodologies for Estimating air pollutant Emissions from Transport (MEET). The database operates on statistical data provided by Eurostat, which describe vessel and freight movements from and towards EU 15 major ports. Data are at port to Maritime Coastal Area (MCA...

  1. GRACE Assimilation into Hydrological Model Improves Representation of Drought-induced Groundwater Trend over Murray-Darling Basin, Australia

    Science.gov (United States)

    Schumacher, Maike; Forootan, Ehsan; Van Dijk, Albert I. J. M.; Müller Schmied, Hannes; Crosbie, Russell S.; Kusche, Jürgen; Döll, Petra

    2016-04-01

    The Murray-Darling Basin, one of the largest and driest river basins over the world, experienced a long-term drought (over 2003-2009), the so-called Millennium Drought. As a result, the terrestrial water storage in the region decreased, which was attributed to dry meteorological conditions and extensive irrigation for agriculture. We used simulations of the WaterGAP Global Hydrology Model (WGHM) driven by monthly climate fields from the Climate Research Unit's Time Series (CRU TS 3.2) and precipitation data from the Global Precipitation Climatology Center (GPCC) to estimate linear trends in soil, surface and groundwater compartments, as well as total water storage changes (TWSC). However, the model was not able to capture the effect of the Millennium Drought on the storage compartments likely due to missing processes in dry regions or climate forcing uncertainties. Particularly, TWSC simulated by standard WGHM did not reproduce the negative trend during 2003-2009. Therefore, in this study, we investigate whether assimilating TWSC from the Gravity Recovery And Climate Experiment (GRACE) satellite mission into WGHM enables a more realistic representation of the Millennium Drought on the basin hydrology. Firstly, the quality of monthly GRACE TWSC and its post-processing over the Murray-Darling Basin was assessed. An improved calibration and data assimilation (C/DA) approach (Schumacher et al., JoG-2016) was then applied to integrate GRACE TWSC along with its full error covariance information into WGHM during 2003-2009. Independent observations of soil moisture, groundwater and surface water extent were used to validate the model outputs after C/DA. Our investigations indicate that the integration of GRACE data indeed introduces a negative trend to TWSC simulations of WGHM, which occurred predominantly in the south (Murray Basin). The trend was found to be associated with the changes in groundwater storage, which was confirmed through validation with in

  2. Content Analysis of Research Trends in Instructional Design Models: 1999-2014

    Science.gov (United States)

    Göksu, Idris; Özcan, Kursat Volkan; Çakir, Recep; Göktas, Yuksel

    2017-01-01

    This study examines studies on instructional design models by applying content analysis. It covers 113 papers published in 44 international Social Science Citation Index (SSCI) and Science Citation Index (SCI) journals. Studies on instructional design models are explored in terms of journal of publication, preferred model, country where the study…

  3. Development of time-trend model for analysing and predicting case pattern of dog bite injury induced rabies-like-illness in Liberia, 2014-2017.

    Science.gov (United States)

    Jomah, N D; Ojo, J F; Odigie, E A; Olugasa, B O

    2014-12-01

    The post-civil war records of dog bite injuries (DBI) and rabies-like-illness (RLI) among humans in Liberia is a vital epidemiological resource for developing a predictive model to guide the allocation of resources towards human rabies control. Whereas DBI and RLI are high, they are largely under-reported. The objective of this study was to develop a time model of the case-pattern and apply it to derive predictors of time-trend point distribution of DBI-RLI cases. A retrospective 6 years data of DBI distribution among humans countrywide were converted to quarterly series using a transformation technique of Minimizing Squared First Difference statistic. The generated dataset was used to train a time-trend model of the DBI-RLI syndrome in Liberia. An additive detenninistic time-trend model was selected due to its performance compared to multiplication model of trend and seasonal movement. Parameter predictors were run on least square method to predict DBI cases for a prospective 4 years period, covering 2014-2017. The two-stage predictive model of DBI case-pattern between 2014 and 2017 was characterised by a uniform upward trend within Liberia's coastal and hinterland Counties over the forecast period. This paper describes a translational application of the time-trend distribution pattern of DBI epidemics, 2008-2013 reported in Liberia, on which a predictive model was developed. A computationally feasible two-stage time-trend permutation approach is proposed to estimate the time-trend parameters and conduct predictive inference on DBI-RLI in Liberia.

  4. Deterministic and stochastic trends in the Lee-Carter mortality model

    DEFF Research Database (Denmark)

    Callot, Laurent; Haldrup, Niels; Kallestrup-Lamb, Malene

    2015-01-01

    mortality data. We find empirical evidence that this feature of the Lee–Carter model overly restricts the system dynamics and we suggest to separate the deterministic and stochastic time series components at the benefit of improved fit and forecasting performance. In fact, we find that the classical Lee......) factor model where one factor is deterministic and the other factors are stochastic. This feature generalizes to the range of models that extend the Lee–Carter model in various directions.......The Lee and Carter (1992) model assumes that the deterministic and stochastic time series dynamics load with identical weights when describing the development of age-specific mortality rates. Effectively this means that the main characteristics of the model simplify to a random walk model with age...

  5. Deterministic and stochastic trends in the Lee-Carter mortality model

    DEFF Research Database (Denmark)

    Callot, Laurent; Haldrup, Niels; Kallestrup-Lamb, Malene

    that characterizes mortality data. We find empirical evidence that this feature of the Lee-Carter model overly restricts the system dynamics and we suggest to separate the deterministic and stochastic time series components at the benefit of improved fit and forecasting performance. In fact, we find...... as a two (or several)-factor model where one factor is deterministic and the other factors are stochastic. This feature generalizes to the range of models that extend the Lee-Carter model in various directions.......The Lee and Carter (1992) model assumes that the deterministic and stochastic time series dynamics loads with identical weights when describing the development of age specific mortality rates. Effectively this means that the main characteristics of the model simplifies to a random walk model...

  6. Time Trend of the People lost follow up on Antiretroviral Therapy (ART Services in Nepal: A Epidemiological Modelling

    Directory of Open Access Journals (Sweden)

    Brijesh Sathian

    2014-06-01

    Full Text Available Background: The real state about the spread of the HIV epidemic in Nepal is not clear since the details available are on the basis of repeated integrated biological and behavioral surveillance. Objective To study the trends of People lost follow up on ART in future. Material and methods: A retrospective study was carried out on the data collected from the Health ministry records of Nepal, between 2006 and 2012. Descriptive statistics and statistical modelling were used for the analysis and forecasting of data. Results: Including the constant term from the equation, the quadratic model was the best fit, for the forecasting of People lost follow up on ART. Using quadratic equation, it is estimated that 4331 reported number of People lost follow up on ART will be there in Nepal by the year 2020. Conclusion: The People lost follow up on ART in Nepal are having an increasing trend. Estimates of the total number of People lost follow up on ART attributable to the major routes of infection make an important contribution to public health policy. They can be used for the planning of healthcare services and for contributing to estimates of the future numbers with People lost follow up on ART used for planning health promotion programmes.

  7. Variations and trends of terrestrial NPP and its relation to climate change in the 10 CMIP5 models

    Indian Academy of Sciences (India)

    Suosuo Li; Shihua Lü; Yuanpu Liu; Yanhong Gao; Yinhuan Ao

    2015-03-01

    Using global terrestrial ecosystem net primary productivity (NPP) data, we validated the simulated multi-model ensemble (MME) NPP, analyzed the spatial distribution of global NPP and explored the relationship between NPP and climate variations in historical scenarios of 10 CMIP5 models. The results show that the global spatial pattern of simulated terrestrial ecosystem NPP, is consistent with IGBP NPP, but the values have some differences and there is a huge uncertainty. Considering global climate change, near surface temperature is the major factor affecting the terrestrial ecosystem, followed by the precipitation. This means terrestrial ecosystem NPP is more closely related to near surface temperature than precipitation. Between 1976 and 2005, NPP shows an obvious increasing temporal trend, indicating the terrestrial ecosystem has had a positive response to climate change. MME NPP has increased 3.647PgC during historical period, which shows an increasing temporal trend of 3.9 gCm−2∙100 yr−2 in the past 150 years, also indicating that the terrestrial ecosystem has shown a positive response to climate change in past 150 years.

  8. Calibration of indium response functions in an Au-In-BSE system up to 800 MeV.

    Science.gov (United States)

    Wang, Zhonglu; Howell, Rebecca M; Burgett, Eric A; Kry, Stephen F; Hertel, Nolan E; Salehpour, Mohammad

    2010-06-01

    Calibration of the response functions of a gold (Au)-indium (In) dual foil Bonner sphere extended (BSE) system was described. The response of the In and Au foil of the system was calculated using MCNPX code with different activation cross-sectional libraries: (ACTL and ENDF VI for gold and ACTL and 532DOS2 for In). To verify and correct the calculated response functions the Bonner sphere set (BSS) was irradiated using (252)Cf and (241)AmBe sources of known neutron strengths for neutrons ranging from thermal to 20 MeV, and was irradiated at the 800-MeV neutron beam of the Los Alamos Neutron Science Center. The neutron spectrum of the 800 MeV beam was determined using time-of-flight (TOF) technique. We observed that the uncertainty of activation cross section in the resonance region can result in great uncertainty in the MCNPX-calculated response functions of activation foil-based BSS. The MCNPX-calculated response functions must be corrected using neutron sources of known spectrum and strength.

  9. Trend obchodu pivem

    OpenAIRE

    Kolář, Petr

    2016-01-01

    Thesis The beer trade trends identifies variables which have an impact on the consumption of beer and predicts the trend of trade in beer in the Czech Republic in the globalization context. To achieve the results was used linear econometric model. Using the Method of least squares determined the size and direction of individual variables for beer consumption. Based on the verified model is a model applicated and based on software Gretl is predicted the beer consumption for a period of 3 ye...

  10. Use of a multistage model to predict time trends in smoking induced lung cancer.

    OpenAIRE

    Swartz, J B

    1992-01-01

    STUDY OBJECTIVE--The aims were to use a mathematical model to predict the time course of smoking induced lung cancer, and to investigate to what extent the most recent increases in lung cancer mortality are due to cigarette smoking. DESIGN--A mathematical model was developed and solved by simulation to construct detailed smoking histories of the US white male population given available prevalence data by age and cohort. A multistage carcinogenesis model was used to predict the time course of ...

  11. Levels, fluxes and time trends of persistent organic pollutants in Lake Thun, Switzerland: Combining trace analysis and multimedia modeling

    Energy Technology Data Exchange (ETDEWEB)

    Bogdal, Christian [Institute for Chemical and Bioengineering, ETH Zurich, Wolfgang-Pauli-Strasse 10, CH-8093 Zuerich (Switzerland); Empa, Swiss Federal Laboratories for Materials Testing and Research, Uberlandstrasse 129, CH-8600 Duebendorf (Switzerland); Scheringer, Martin, E-mail: scheringer@chem.ethz.ch [Institute for Chemical and Bioengineering, ETH Zurich, Wolfgang-Pauli-Strasse 10, CH-8093 Zuerich (Switzerland); Schmid, Peter [Empa, Swiss Federal Laboratories for Materials Testing and Research, Uberlandstrasse 129, CH-8600 Duebendorf (Switzerland); Blaeuenstein, Markus [Institute for Chemical and Bioengineering, ETH Zurich, Wolfgang-Pauli-Strasse 10, CH-8093 Zuerich (Switzerland); Kohler, Martin [State Food Law Enforcement Authority, Werkhofstrasse 5, CH-4509 Solothurn (Switzerland); Hungerbuehler, Konrad [Institute for Chemical and Bioengineering, ETH Zurich, Wolfgang-Pauli-Strasse 10, CH-8093 Zuerich (Switzerland)

    2010-08-01

    Levels, mass fluxes, and time trends of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in Lake Thun, a peri-Alpine lake, are investigated. We present measurements of PBDEs and PCBs in air, lake water, lake sediment, and tributary water. These measurements are combined with a multimedia fate model, based on site-specific environmental parameters from the lake catchment. Measured loadings of PBDEs and PCBs in air and tributaries were used to drive the model. The model satisfactorily reproduces PBDE and PCB congener patterns in water and sediment, but it tends to yield concentrations in water below the measurements and concentrations in sediment exceeding the measurements. A sensitivity analysis reveals that partitioning of PBDEs and PCBs between the aqueous dissolved phase and suspended particulate matter in the water column strongly affects the model results, in particular the concentrations in water and sediment. For lower-brominated PBDEs, approximately 70% and 30% of input into the lake stems from atmospheric deposition and from tributaries, respectively. For heavier PBDEs and all PCBs, rivers appear to deliver the major load (64-92%). Waste water effluents are of minor importance. 50-90% of the total input is buried in the permanent sediment. Sediment burial makes PBDEs and PCBs less available for recycling in the environment, and reduces concentrations in the outflowing river. If use of deca-BDE increases in the future, levels in Lake Thun will follow the same trend. If the use and resulting environmental emissions decrease, concentrations in water will rapidly decline, according to our calculations, while sediment levels will decrease at a considerably slower rate.

  12. Examining secular trends and seasonality in count data using dynamic generalized linear modelling: a new methodological approach illustrated with hospital discharge data on myocardial infarction

    DEFF Research Database (Denmark)

    Lundbye-Christensen, Søren; Dethlefsen, Claus; Gorst-Rasmussen, Anders;

    2009-01-01

    . Records were updated daily. A dynamic model with a seasonal pattern and an approximately linear trend was fitted to the data, and diagnostic plots indicated a good model fit. The analysis conducted with the dynamic model revealed peaks coinciding with above-average influenza A activity. On average...

  13. Observations and modelling of the global distribution and long-term trend of atmospheric 14CO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Levin, Ingeborg; Naegler, Tobias; Kromer, Bernd; Wagenbach, Dietmar (Inst. fuer Umweltphysik, Univ. of Heidelberg, Heidelberg (Germany)). e-mail: Ingeborg.Levin@iup.uni-heidelberg.de; Diehl, Moritz (Interdisziplinaeres Zentrum fuer wissenschaftliches Rechnen (IWR), Univ. of Heidelberg, Heidelberg (Germany)); Francey, Roger J.; Steele, L. Paul (CSIRO Marine and Atmospheric Research (CMAR), Aspendale, Victoria (Australia)); Gomez-Pelaez, Angel J. (Izana Atmospheric Research Center, Meteorological State Agency of Spain (AEMET), Santa Cruz de Tenerife (Spain)); Weller, Rolf (Alfred Wegener Inst. for Polar and Marine Research, Bremerhaven (Germany)); Worthy, Douglas E. (Environment Canada, Climate Research Div., Toronto, ON (Canada))

    2009-07-01

    Global high-precision atmospheric DELTA14CO{sub 2} records covering the last two decades are presented, and evaluated in terms of changing (radio)carbon sources and sinks, using the coarse-grid carbon cycle model GRACE. Dedicated simulations of global trends and interhemispheric differences with respect to atmospheric CO{sub 2} as well as delta13CO{sub 2} and DELTA14CO{sub 2}, are shown to be in good agreement with the available observations (1940-2008). While until the 1990s the decreasing trend of DELTA14CO{sub 2} was governed by equilibration of the atmospheric bomb 14C perturbation with the oceans and terrestrial biosphere, the largest perturbation today are emissions of 14C-free fossil fuel CO{sub 2}. This source presently depletes global atmospheric DELTA14CO{sub 2} by 1.2-1.4%/yr, which is partially compensated by 14CO{sub 2} release from the biosphere, industrial 14C emissions and natural 14C production. Fossil fuel emissions also drive the changing north-south gradient, showing lower DELTA14C in the northern hemisphere only since 2002. The fossil fuel-induced north/south (and also troposphere-stratosphere) DELTA14CO{sub 2} gradient today also drives the tropospheric DELTA14CO{sub 2} seasonality through variations of air mass exchange between these atmospheric compartments. Neither the observed temporal trend nor the DELTA14CO{sub 2} north-south gradient may constrain global fossil fuel CO{sub 2} emissions to better than 25%, due to large uncertainties in other components of the (radio)carbon cycle

  14. Trending in Probability of Collision Measurements via a Bayesian Zero-Inflated Beta Mixed Model

    Science.gov (United States)

    Vallejo, Jonathon; Hejduk, Matt; Stamey, James

    2015-01-01

    We investigate the performance of a generalized linear mixed model in predicting the Probabilities of Collision (Pc) for conjunction events. Specifically, we apply this model to the log(sub 10) transformation of these probabilities and argue that this transformation yields values that can be considered bounded in practice. Additionally, this bounded random variable, after scaling, is zero-inflated. Consequently, we model these values using the zero-inflated Beta distribution, and utilize the Bayesian paradigm and the mixed model framework to borrow information from past and current events. This provides a natural way to model the data and provides a basis for answering questions of interest, such as what is the likelihood of observing a probability of collision equal to the effective value of zero on a subsequent observation.

  15. Modeling and Forecasting of Water Demand in Isfahan Using Underlying Trend Concept and Time Series

    Directory of Open Access Journals (Sweden)

    H. Sadeghi

    2016-02-01

    Full Text Available Introduction: Accurate water demand modeling for the city is very important for forecasting and policies adoption related to water resources management. Thus, for future requirements of water estimation, forecasting and modeling, it is important to utilize models with little errors. Water has a special place among the basic human needs, because it not hampers human life. The importance of the issue of water management in the extraction and consumption, it is necessary as a basic need. Municipal water applications is include a variety of water demand for domestic, public, industrial and commercial. Predicting the impact of urban water demand in better planning of water resources in arid and semiarid regions are faced with water restrictions. Materials and Methods: One of the most important factors affecting the changing technological advances in production and demand functions, we must pay special attention to the layout pattern. Technology development is concerned not only technically, but also other aspects such as personal, non-economic factors (population, geographical and social factors can be analyzed. Model examined in this study, a regression model is composed of a series of structural components over time allows changed invisible accidentally. Explanatory variables technology (both crystalline and amorphous in a model according to which the material is said to be better, but because of the lack of measured variables over time can not be entered in the template. Model examined in this study, a regression model is composed of a series of structural component invisible accidentally changed over time allows. In this study, structural time series (STSM and ARMA time series models have been used to model and estimate the water demand in Isfahan. Moreover, in order to find the efficient procedure, both models have been compared to each other. The desired data in this research include water consumption in Isfahan, water price and the monthly pay

  16. Competence Model and Modern Trends of Development of the Russian Institute of Technical Customer

    Directory of Open Access Journals (Sweden)

    Mishlanova Marina

    2017-01-01

    Full Text Available Article considers modern maintenance and development of the management actor by the investment-construction projects of the technical customer. Urgent problems of the formation of Institute of the technical customer establishment are allocated. Elementary competence model is presented: based competences of technical customer, model of the primary competence, example of the operational level of the model. Analysis of the development of the Institute of the technical customer was performed: compliance with current realities of investment-construction activities, improvement of contractual relations, compliance with international standards, state participation, creation of the single technical customer. Necessity of development of competence models for the urgent justification of professional standards is assessed. The possibility of modeling of the competencies and functions of technical customer in approach to the FIDIC-model was revealed. Possibility of usage of the competence model of the technical customer on the stage of building in terms of public-private partnership. Results show the direction for further researches.

  17. Multiscale Modeling of Multi-decadal Trends in Ozone across the Northern Hemisphere & United States

    Science.gov (United States)

    Both observational and modeling studies have demonstrated that pollutants near the Earth’s surface can be convectively lofted to higher altitudes where strong winds can efficiently transport them from one continent to another, thereby impacting air quality on intercontinent...

  18. Estimating the prevalence of breast cancer using a disease model: data problems and trends

    NARCIS (Netherlands)

    M.E. Kruijshaar (Michelle); J.J.M. Barendregt (Jan); L.V. van de Poll-Franse (Lonneke)

    2003-01-01

    textabstractBACKGROUND: Health policy and planning depend on quantitative data of disease epidemiology. However, empirical data are often incomplete or are of questionable validity. Disease models describing the relationship between incidence, prevalence and mortality are used to d

  19. Recent Trends in Detection of Huntingtin and Preclinical Models of Huntington's Disease.

    Science.gov (United States)

    Mantha, Neelima; Das, Nandita G; Das, Sudip K

    2014-01-01

    Huntington's disease is a genetically inherited neurodegenerative disease that is characterized by neuronal cell death in the brain. Molecular biology techniques to detect and quantify huntingtin protein in biological samples involve fluorescence imaging, western blotting, and PCR. Modified cell lines are widely used as models for Huntington's disease for preclinical screening of drugs to study their ability to suppress the expression of huntingtin. Although worm and fly species have been experimented on as models for Huntington's disease, the most successful animal models have been reported to be primates. This review critically analyses the molecular biology techniques for detection and quantitation of huntingtin and evaluates the various animal species for use as models for Huntington's disease.

  20. Territorial and branch associations of the oil and gas complex and the trends in their modeling

    Energy Technology Data Exchange (ETDEWEB)

    Chudnovskaya, S.N.

    1983-01-01

    Tendencies in the development of the Western Siberian region are studied on the basis of economic and mathematical modeling. The basic interrelations for an expanded system of the oil and gas complex are examined.

  1. Can natural variability explain the discrepancy between observed and modeled sea ice trends?

    CERN Document Server

    Rosenblum, Erica

    2016-01-01

    Observations indicate that the Arctic sea ice cover is rapidly retreating while the Antarctic sea ice cover is steadily expanding. State-of-the-art climate models, by contrast, tend to predict a moderate decrease in both the Arctic and Antarctic sea ice covers. A number of recent studies have attributed this discrepancy in each hemisphere to natural variability, suggesting that the models are consistent with the observations when simulated natural variability is taken into account. Here we examine sea ice changes during 1979-2013 in simulations from the most recent Coupled Model Intercomparison Project (CMIP5) as well as the Community Earth System Model Large Ensemble (CESM-LE). We find that accurately simulated Arctic sea ice retreat occurs only in simulations with too much global warming, whereas accurately simulated Antarctic sea ice expansion tends to occur in simulations with too little global warming. We show that because of this, simulations from both ensembles do not capture the observed asymmetry bet...

  2. Evolutionary ecology in silico: Does mathematical modelling help in understanding `generic' trends?

    Indian Academy of Sciences (India)

    Debashish Chowdhury; Dietrich Stauffer

    2005-03-01

    Motivated by the results of recent laboratory experiments, as well as many earlier field observations, that evolutionary changes can take place in ecosystems over relatively short ecological time scales, several ‘unified’ mathematical models of evolutionary ecology have been developed over the last few years with the aim of describing the statistical properties of data related to the evolution of ecosystems. Moreover, because of the availability of sufficiently fast computers, it has become possible to carry out detailed computer simulations of these models. For the sake of completeness and to put these recent developments in perspective, we begin with a brief summary of some older models of ecological phenomena and evolutionary processes. However, the main aim of this article is to review critically these ‘unified’ models, particularly those published in the physics literature, in simple language that makes the new theories accessible to a wider audience.

  3. Speed and Trend of China’s Urbanization: A Comparative Study Based on Cross-Country Panel Data Model

    Institute of Scientific and Technical Information of China (English)

    Chen; Ming; Wang; Kai; Zhang; Qingfei

    2015-01-01

    This article investigates the speed and trend of urbanization in China and other countries by applying a non-linear model with panel data from 41 big countries with a population of over ten millions. It fi nds that the relationship between China’s urbanization and economic development presents a less fl uctuating S-shaped curve which refl ects the variation in urbanization between China and other large countries. Calculated in line with the PPP(purchasing power parity) of 2009, China’s rapid urbanization started when the GDP per capita reached 1,339 US dollars and the urbanization level was 22.92%, though lower than the world average by 5.16 percentage points. China’s rapid urbanization ends when the GDP per capita reaches 12,088 US dollars and the urbanization level amounts to 50.69%, with the percentage lower than the world average by 16.32 percentage points. And China’s urbanization will be completed when the GDP per capita climbs to 28,306 US dollars and the urbanization level reaches 61.55%, 12.32 percentage points lower than the world average then. Nevertheless, the unique background of China, including its socio-economic development, land institutional arrangements, and authoritarian political system, will have a great impact on the urbanization trend. Particularly, as China’s socio-economic reform deepens, China’s urbanization level will reach a new height.

  4. Polar ozone depletion and trends as represented by the Whole Atmospheric Community Climate Model (WACCM)

    Science.gov (United States)

    Kinnison, Douglas; Solomon, Susan; Ivy, Diane; Mills, Michael; Neely, Ryan, III; Schmidt, Anja; Garcia, Rolando; Smith, Anne

    2016-04-01

    The Whole Atmosphere Community Climate Model, Version 4 (WACCM4) is a comprehensive numerical model, spanning the range of altitude from the Earth's surface to the lower thermosphere [Garcia et al., JGR, 2007; Kinnison et al., JGR, 2007; Marsh et al., J. of Climate, 2013]. WACCM4 is based on the framework of the NCAR Community Atmosphere Model, version 4 (CAM4), and includes all of the physical parameterizations of CAM4 and a finite volume dynamical core for the tracer advection. This version has a detailed representation of tropospheric and middle atmosphere chemical and physical processes. Simulations completed for the SPARC Chemistry Climate Model Initiative (CCMI), REFC1, REFC2, SENSC2, and REFC1SD scenarios are examined (see Eyring et al., SPARC Newsletter, 2013). Recent improvements in model representation of orographic gravity wave processes strongly impact temperature and therefore polar ozone depletion as well as its subsequent recovery. Model representation of volcanic events will also be shown to be important for ozone loss. Evaluation of polar ozone depletion processes (e.g., dehydration, denitrification, chemical activation) with key observations will be performed and the impact on future ozone recovery will be identified.

  5. Emerging trends in evolving networks: Recent behaviour dominant and non-dominant model

    Science.gov (United States)

    Abbas, Khushnood; Shang, Mingsheng; Luo, Xin; Abbasi, Alireza

    2017-10-01

    Novel phenomenon receives similar attention as popular one. Therefore predicting novelty is as important as popularity. Emergence is the side effect of competition and ageing in evolving systems. Recent behaviour or recent link gain in networks plays an important role in emergence. We exploited this wisdom and came up with two models considering different scenarios and systems. Where recent behaviour dominates over total behaviour (total link gain) in the first one, and recent behaviour is as important as total behaviour for future link gain in the second one. It supposes that random walker walks on a network and can jump to any node, the probability of jumping or making a connection to other node is based on which node is recently more active or receiving more links. In our assumption, the random walker can also jump to the node which is already popular but recently not popular. We are able to predict emerging nodes which are generally suppressed under preferential attachment effect. To show the performance of our model we have conducted experiments on four real data sets namely, MovieLens, Netflix, Facebook and Arxiv High Energy Physics paper citation. For testing our model we used four information retrieval indices namely Precision, Novelty, Area Under Receiving Operating Characteristic (AUC) and Kendal's rank correlation coefficient. We have used four benchmark models for validating our proposed models. Although our model does not perform better in all the cases but, it has theoretical significance in working better for recent behaviour dominated systems.

  6. An HIV epidemic model based on viral load dynamics: value in assessing empirical trends in HIV virulence and community viral load.

    Science.gov (United States)

    Herbeck, Joshua T; Mittler, John E; Gottlieb, Geoffrey S; Mullins, James I

    2014-06-01

    Trends in HIV virulence have been monitored since the start of the AIDS pandemic, as studying HIV virulence informs our understanding of HIV epidemiology and pathogenesis. Here, we model changes in HIV virulence as a strictly evolutionary process, using set point viral load (SPVL) as a proxy, to make inferences about empirical SPVL trends from longitudinal HIV cohorts. We develop an agent-based epidemic model based on HIV viral load dynamics. The model contains functions for viral load and transmission, SPVL and disease progression, viral load trajectories in multiple stages of infection, and the heritability of SPVL across transmissions. We find that HIV virulence evolves to an intermediate level that balances infectiousness with longer infected lifespans, resulting in an optimal SPVL∼4.75 log10 viral RNA copies/mL. Adaptive viral evolution may explain observed HIV virulence trends: our model produces SPVL trends with magnitudes that are broadly similar to empirical trends. With regard to variation among studies in empirical SPVL trends, results from our model suggest that variation may be explained by the specific epidemic context, e.g. the mean SPVL of the founding lineage or the age of the epidemic; or improvements in HIV screening and diagnosis that results in sampling biases. We also use our model to examine trends in community viral load, a population-level measure of HIV viral load that is thought to reflect a population's overall transmission potential. We find that community viral load evolves in association with SPVL, in the absence of prevention programs such as antiretroviral therapy, and that the mean community viral load is not necessarily a strong predictor of HIV incidence.

  7. An HIV epidemic model based on viral load dynamics: value in assessing empirical trends in HIV virulence and community viral load.

    Directory of Open Access Journals (Sweden)

    Joshua T Herbeck

    2014-06-01

    Full Text Available Trends in HIV virulence have been monitored since the start of the AIDS pandemic, as studying HIV virulence informs our understanding of HIV epidemiology and pathogenesis. Here, we model changes in HIV virulence as a strictly evolutionary process, using set point viral load (SPVL as a proxy, to make inferences about empirical SPVL trends from longitudinal HIV cohorts. We develop an agent-based epidemic model based on HIV viral load dynamics. The model contains functions for viral load and transmission, SPVL and disease progression, viral load trajectories in multiple stages of infection, and the heritability of SPVL across transmissions. We find that HIV virulence evolves to an intermediate level that balances infectiousness with longer infected lifespans, resulting in an optimal SPVL∼4.75 log10 viral RNA copies/mL. Adaptive viral evolution may explain observed HIV virulence trends: our model produces SPVL trends with magnitudes that are broadly similar to empirical trends. With regard to variation among studies in empirical SPVL trends, results from our model suggest that variation may be explained by the specific epidemic context, e.g. the mean SPVL of the founding lineage or the age of the epidemic; or improvements in HIV screening and diagnosis that results in sampling biases. We also use our model to examine trends in community viral load, a population-level measure of HIV viral load that is thought to reflect a population's overall transmission potential. We find that community viral load evolves in association with SPVL, in the absence of prevention programs such as antiretroviral therapy, and that the mean community viral load is not necessarily a strong predictor of HIV incidence.

  8. The Soil and Water Assessment Tool (SWAT) Ecohydrological Model Circa 2015: Global Application Trends, Insights and Issues

    Science.gov (United States)

    Gassman, P. W.; Arnold, J. G.; Srinivasan, R.

    2015-12-01

    The Soil and Water Assessment Tool (SWAT) is one of the most widely used watershed-scale water quality models in the world. Over 2,000 peer-reviewed SWAT-related journal articles have been published and hundreds of other studies have been published in conference proceedings and other formats. The use of SWAT was initially concentrated in North America and Europe but has also expanded dramatically in other countries and regions during the past decade including Brazil, China, India, Iran, South Korea, Southeast Asia and eastern Africa. The SWAT model has proven to be a very flexible tool for investigating a broad range of hydrologic and water quality problems at different watershed scales and environmental conditions, and has proven very adaptable for applications requiring improved hydrologic and other enhanced simulation needs. We investigate here the various technological, networking, and other factors that have supported the expanded use of SWAT, and also highlight current worldwide simulation trends and possible impediments to future increased usage of the model. Examples of technological advances include easy access to web-based documentation, user-support groups, and SWAT literature, a variety of Geographic Information System (GIS) interface tools, pre- and post-processing calibration software and other software, and an open source code which has served as a model development catalyst for multiple user groups. Extensive networking regarding the use of SWAT has further occurred via internet-based user support groups, model training workshops, regional working groups, regional and international conferences, and targeted development workshops. We further highlight several important model development trends that have emerged during the past decade including improved hydrologic, cropping system, best management practice (BMP) and pollutant transport simulation methods. In addition, several current SWAT weaknesses will be addressed and key development needs will be

  9. Estimating systematic continuous-time trends in recidivism using a non-gaussian panel data model

    NARCIS (Netherlands)

    Koopman, S.J.; Ooms, M.; Montfort, van K.; Geest, van der W.

    2008-01-01

    We model panel data of crime careers of juveniles from a Dutch Judicial Juvenile Institution. The data are decomposed into a systematic and an individual-specific component, of which the systematic component reflects the general time-varying conditions including the criminological climate. Within a

  10. Estimating the prevalence of breast cancer using a disease model: Data problems and trends

    NARCIS (Netherlands)

    M.E. Kruijshaar (Michelle); J.J.M. Barendregt (Jan); L.V. van de Poll-Franse (Lonneke)

    2003-01-01

    textabstractBackground. Health policy and planning depend on quantitative data of disease epidemiology. However, empirical data are often incomplete or are of questionable validity. Disease models describing the relationship between incidence, prevalence and mortality are used to detect data problem

  11. Migration Trends in the Kansas Ogallala Region and the Internal Colonial Dependency Model.

    Science.gov (United States)

    White, Stephen E.

    1998-01-01

    Examines population change in the High Plains of western Kansas in terms of an internal colonialism-dependency model. Identifies a wide range of colonial dependent characteristics, including long-term population decline, high median age, highly channelized migration flows, and continuing outmigration of the region's most educated inhabitants.…

  12. Modelling trends in soil solution concentrations under five forest-soil combinations in the Netherlands

    NARCIS (Netherlands)

    Salm, van der C.; Vries, de W.; Kros, J.

    1996-01-01

    The influence of forest and soil properties on changes in soil solution concentration upon a reduction deposition was examined for five forest-soil combinations with the dynamic RESAM model. Predicted concentrations decreased in the direction Douglas fir - Scotch pine - oak, due to decreased filteri

  13. LDA Based Face Recognition by Using Hidden Markov Model in Current Trends

    Directory of Open Access Journals (Sweden)

    S.Sharavanan

    2009-10-01

    Full Text Available Hidden Markov model (HMM is a promising method that works well for images with variations in lighting, facial expression, and orientation. Face recognition draws attention as a complex task due to noticeable changes produced on appearance by illumination, facial expression, size, orientation and other external factors. To process images using HMM, the temporal or space sequences are to be considered. In simple terms HMM can be defined as set of finite states with associated probability distributions. Only the outcome is visible to the external user not the states and hence the name Hidden Markov Model. The paper deals with various techniques and methodologies used for resolving the problem .We discuss about appearance based, feature based, model based and hybrid methods for face identification. Conventional techniques such as Principal Component Analysis (PCA, Linear Discriminant Analysis (LDA, Independent Component Analysis (ICA, and feature based Elastic Bunch Graph Matching (EBGM and 2D and 3D face models are well-known for face detection and recognition.

  14. Modeling, design, and control of flexible manipulator arms: Status and trends

    Science.gov (United States)

    Book, Wayne J.

    1989-01-01

    The desire for higher performance manipulators has lead to dynamic behavior in which the flexibility is an essential aspect. The mathematical representations commonly used in modeling flexible arms and arms with flexible drives are examined first. Then design considerations directly arising from the flexible nature of the arm are discussed. Finally, controls of joints for general and tip motion are discussed.

  15. Using a dynamic model to assess trends in land degradation by water erosion in Spanish Rangelands

    Science.gov (United States)

    Ibáñez, Javier; Francisco Lavado-Contador, Joaquín; Schnabel, Susanne; Pulido-Fernández, Manuel; Martínez Valderrama, Jaime

    2014-05-01

    This work presents a model aimed at evaluating land degradation by water erosion in dehesas and montados of the Iberian Peninsula, that constitute valuable rangelands in the area. A multidisciplinary dynamic model was built including weather, biophysical and economic variables that reflect the main causes and processes affecting sheet erosion on hillsides of the study areas. The model has two main and two derived purposes: Purpose 1: Assessing the risk of degradation that a land-use system is running. Derived purpose 1: Early warning about land-use systems that are particularly threatened by degradation. Purpose 2: Assessing the degree to which different factors would hasten degradation if they changed from the typical values they show at present. Derived purpose 2: Evaluating the role of human activities on degradation. Model variables and parameters have been calibrated for a typical open woodland rangeland (dehesa or montado) defined along 22 working units selected from 10 representative farms and distributed throughout the Spanish region of Extremadura. The model is the basis for a straightforward assessment methodology which is summarized by the three following points: i) The risk of losing a given amount of soil before a given number of years was specifically estimated as the percentage of 1000 simulations where such a loss occurs, being the simulations run under randomly-generated scenarios of rainfall amount and intensity and meat and supplemental feed market prices; ii) Statistics about the length of time that a given amount of soil takes to be lost were calculated over 1000 stochastic simulations run until year 1000, thereby ensuring that such amount of soil has been lost in all of the simulations, i.e. the total risk is 100%; iii) Exogenous factors potentially affecting degradation, mainly climatic and economic, were ranked in order of importance by means of a sensitivity analysis. Particularly remarkable in terms of model performance is the major role

  16. The simulation of cutoff lows in a regional climate model: reliability and future trends

    Energy Technology Data Exchange (ETDEWEB)

    Grose, Michael R. [University of Tasmania, Antarctic Climate and Ecosystems Cooperative Research Centre (ACE CRC), Private Bag 80, Hobart, TAS (Australia); Pook, Michael J.; McIntosh, Peter C.; Risbey, James S. [CSIRO Marine and Atmospheric Research, Centre for Australian Weather and Climate Research (CAWCR), Hobart, TAS (Australia); Bindoff, Nathaniel L. [University of Tasmania, Antarctic Climate and Ecosystems Cooperative Research Centre (ACE CRC), Private Bag 80, Hobart, TAS (Australia); CSIRO Marine and Atmospheric Research, Centre for Australian Weather and Climate Research (CAWCR), Hobart, TAS (Australia); University of Tasmania, Institute of Marine and Antarctic Studies (IMAS), Private Bag 129, Hobart, TAS (Australia)

    2012-07-15

    Cutoff lows are an important source of rainfall in the mid-latitudes that climate models need to simulate accurately to give confidence in climate projections for rainfall. Coarse-scale general circulation models used for climate studies show some notable biases and deficiencies in the simulation of cutoff lows in the Australian region and important aspects of the broader circulation such as atmospheric blocking and the split jet structure observed over Australia. The regional climate model conformal cubic atmospheric model or CCAM gives an improvement in some aspects of the simulation of cutoffs in the Australian region, including a reduction in the underestimate of the frequency of cutoff days by more than 15 % compared to a typical GCM. This improvement is due at least in part to substantially higher resolution. However, biases in the simulation of the broader circulation, blocking and the split jet structure are still present. In particular, a northward bias in the central latitude of cutoff lows creates a substantial underestimate of the associated rainfall over Tasmania in April to October. Also, the regional climate model produces a significant north-south distortion of the vertical profile of cutoff lows, with the largest distortion occurring in the cooler months that was not apparent in GCM simulations. The remaining biases and presence of new biases demonstrates that increased horizontal resolution is not the only requirement in the reliable simulation of cutoff lows in climate models. Notwithstanding the biases in their simulation, the regional climate model projections show some responses to climate warming that are noteworthy. The projections indicate a marked closing of the split jet in winter. This change is associated with changes to atmospheric blocking in the Tasman Sea, which decreases in June to November (by up to 7.9 m s{sup -1}), and increases in December to May. The projections also show a reduction in the number of annual cutoff days by 67

  17. Trends in Modelling, Simulation and Design of Water Hydraulic Systems – Motion Control and Open-Ended Solutions

    DEFF Research Database (Denmark)

    Conrad, Finn

    2006-01-01

    The paper presents and discusses a R&D-view on trends in development and best practise in modelling, simulation and design of both low-pressure and high-pressure tap water hydraulic components and systems for motion control as well as open-ended solutions various industrial applications. The focus...... is on the advantages using ordinary tap water and the range of application areas are illustrated with examples, in particular within the food processing industry, humidification operations, water mist systems for fire fighting, high water pressure cleaners, water moisturising systems for wood processing, lumber drying...... is that the components operate with pure water from the tap without additives of any kind. Hence water hydraulics takes the benefit of pure water as fluid being environmentally friendly, easy to clean sanitary design, non-toxic, non-flammable, inexpensive, readily available and easily disposable. The low-pressure tap...

  18. Establishment of a prediction model of changing trends in cardiac hypertrophy disease based on microarray data screening.

    Science.gov (United States)

    Ma, Caiyan; Ying, Yongjun; Zhang, Tianjie; Zhang, Wei; Peng, Hui; Cheng, Xufeng; Xu, Lin; Tong, Hong

    2016-05-01

    The aim of the present study was to construct a mathematical model to predict the changing trends of cardiac hypertrophy at gene level. Microarray data were downloaded from Gene Expression Omnibus database (accession, GSE21600), which included 35 samples harvested from the heart of Wistar rats on postoperative days 1 (D1 group), 6 (D6 group) and 42 (D42 group) following aorta ligation and sham operated Wistar rats, respectively. Each group contained six samples, with the exception of the samples harvested from the aorta ligated group after 6 days, where n=5. Differentially expressed genes (DEGs) were identified using a Limma package in R. Hierarchical clustering analysis was performed on common DEGs in order to construct a linear equation between the D1 and D42 groups, using linear discriminant analysis. Subsequent verification was performed using receiver operating characteristic (ROC) curve and the measurement data at day 42. A total of 319, 44 and 57 DEGs were detected in D1, D6 and D42 sample groups, respectively. AKIP1, ANKRD23, LTBP2, TGF-β2 and TNFRSF12A were identified as common DEGs in all groups. The predicted linear equation between D1 and D42 group was calculated to be y=1.526×-186.671. Assessment of the ROC curve demonstrated that the area under the curve was 0.831, with a specificity and sensitivity of 0.8. As compared with the predictive and measurement data at day 42, the consistency of the two sets of data was 76.5%. In conclusion, the present model may contribute to the early prediction of changing trends in cardiac hypertrophy disease at gene level.

  19. Model-Based Predictions of the Effects of Harvest Mortality on Population Size and Trend of Yellow-Billed Loons

    Science.gov (United States)

    Schmutz, Joel A.

    2009-01-01

    Yellow-billed loons (Gavia adamsii) breed in low densities in northern tundra habitats in Alaska, Canada, and Russia. They migrate to coastal marine habitats at mid to high latitudes where they spend their winters. Harvest may occur throughout the annual cycle, but of particular concern are recent reports of harvest from the Bering Strait region, which lies between Alaska and Russia and is an area used by yellow-billed loons during migration. Annual harvest for this region was reported to be 317, 45, and 1,077 during 2004, 2005, and 2007, respectively. I developed a population model to assess the effect of this reported harvest on population size and trend of yellow-billed loons. Because of the uncertainty regarding actual harvest and definition of the breeding population(s) affected by this harvest, I considered 25 different scenarios. Predicted trends across these 25 scenarios ranged from stability to rapid decline (24 percent per year) with halving of the population in 3 years. Through an assessment of literature and unpublished satellite tracking data, I suggest that the most likely of these 25 scenarios is one where the migrant population subjected to harvest in the Bering Strait includes individuals from breeding populations in Alaska (Arctic coastal plain and the Kotzebue region) and eastern Russia, and for which the magnitude of harvest varies among years and emulates the annual variation of reported harvest during 2004-07 (317, 45, and 1,077 yellow-billed loons). This scenario, which assumes no movement of Canadian breeders through the Bering Strait, predicts a 4.6 percent rate of annual population decline, which would halve the populations in 15 years. Although these model outputs reflect the best available information, confidence in these predictions and applicable scenarios would be greatly enhanced by more information on harvest, rates of survival and reproduction, and migratory pathways.

  20. Statistical Modeling of the Trends Concerning the Number of Hospitals and Medical Centres in Romania

    Directory of Open Access Journals (Sweden)

    Gabriela OPAIT

    2017-04-01

    Full Text Available This study reveals the technique for to achive the shapes of the mathematical models which put in evidence the distributions of the values concerning the number of Hospitals, respectively Medical Centres, in our country, in the time horizon 2005-2014. In the same time, we can to observe the algorithm applied for to construct forecasts about the evolutions regarding the number of Hospitals and Medical Centres in Romania.

  1. Dynamo Models of the Solar Cycle: Current Trends and Future Prospects

    CERN Document Server

    Nandy, Dibyendu

    2011-01-01

    The magnetic cycle of the Sun, as manifested in the cyclic appearance of sunspots, significantly influences our space environment and space-based technologies by generating what is now termed as space weather. Long-term variation in the Sun's magnetic output also influences planetary atmospheres and climate through modulation of solar irradiance. Here, I summarize the current state of understanding of this magnetic cycle, highlighting important observational constraints, detailing the kinematic dynamo modeling approach and commenting on future prospects.

  2. Recent Trends in Detection of Huntingtin and Preclinical Models of Huntington’s Disease

    OpenAIRE

    2014-01-01

    Huntington’s disease is a genetically inherited neurodegenerative disease that is characterized by neuronal cell death in the brain. Molecular biology techniques to detect and quantify huntingtin protein in biological samples involve fluorescence imaging, western blotting, and PCR. Modified cell lines are widely used as models for Huntington’s disease for preclinical screening of drugs to study their ability to suppress the expression of huntingtin. Although worm and fly species have been exp...

  3. Compilation of Global Surface Ozone Observations for Earth System Model Trend Evaluation

    Science.gov (United States)

    Sofen, E. D.; Evans, M. J.

    2014-12-01

    Tropospheric ozone is detrimental to human health and ecosystems, is a greenhouse gas, and plays a role in removing pollutants from the atmosphere. Since the first observations of its concentration in the late 19th century, it has been measured by a range of different approaches (surface instrumental, sondes, satellites). In the last 40 years, global (WMO GAW) and regional networks (EMEP, CASTNET, ...) have been initiated to measure its surface concentration. For data analysis and model comparisons a synthesis of all of this data needs to be undertaken. In this work we collate these observations into a single dataset with some initial quality control and handling of meta-data. We can then generate a range of products (means, medians, percentiles, standard deviations, AOT40, SUMO35, etc.) over a range of timescales (hourly, daily, monthly, annual) on user specified grids suitable for data analysis and model evaluation. We apply objective statistical techniques developed by the paleoclimate reconstruction community to interpolate the data spatially to reconstruct a global map and time series of surface ozone. Novelly, we use global chemical transport model output to infer each measurement's spatial representativeness to account for lifetime and meteorology. We present results of the global interpolation and global and regional averages in surface ozone over the past 40 years and compare them to models. We find that the observational coverage peaked around the year 2002 with good coverage over the northern midlatitudes and Antarctica but poor coverage over the tropics and Southern Hemisphere subtropics due to both the lack of observations and the short lifetime of tropical ozone. Significantly more ozone observations are made globally than are reported to the international datasets reducing the usefulness of these individual observations and making understanding ozone on both regional and global scale more difficult. New observations of surface ozone through the

  4. Modeling water resources trends in Middle East and North Africa towards 2050

    Directory of Open Access Journals (Sweden)

    P. Droogers

    2012-04-01

    Full Text Available Changes in water resources availability can be expected as consequences of climate change, population growth, economic development and environmental considerations. A two-stage modeling approach is used to explore the impact of these changes in the Middle East and North Africa (MENA region. An advanced physical based distributed hydrological model is applied to determine the internal and external renewable water resources for the current situation and under future changes. Subsequently, a water allocation model is used to combine the renewable water resources with sectorial water demands. Results show that total demand in the region will increase to 132 km3 yr−1 in 2050, while total water shortage will grow to 199 km3 yr−1 in 2050 for the average climate change projection; an increase of 157 km3. This increase in shortage is the combined impact of an increase in water demand by 50% with a decrease in water supply by 12%. Uncertainty based on the output of the nine GCMs applied, reveals that expected water shortage ranges from 85 km3 to 283 km3 in 2050. The analysis shows that 22% of the water shortage can be attributed to climate change and 78% to changes in socio-economic factors.

  5. Trend analysis and comparison of basic parameters for tunnel blast design models

    Institute of Scientific and Technical Information of China (English)

    Khalili Soroush; Yavary Mehdi; Ebrahimabadi Arash

    2015-01-01

    One of the most important factors influencing on a tunnel blast efficiency is the proper design of blasting pattern. Among blasting parameters, blasthole diameter and tunnel face area are more significant so that any change in these parameters could finally affect on specific charge and specific drilling. There are mainly two groups of methods for tunnel blast design categorized based on the parallel cuts and angular cuts. In this research, a software for tunnel blast design was developed to analyze the effect and sensi-tiveness of blasthole diameter and the tunnel face area on blasting results in different blast design mod-els. Using the software, it is quickly possible to determine specific charge, specific drilling and number of blastholes for each blast design model. The relations between both of blasthole diameters and the tunnel face area with the above parameters in different blast design models were then investigated to yield a set of equations with the highest correlations to compare the methods. The results showed that angular method requires more blasthole numbers than parallel method in similar condition (blasthole diameter and tunnel face area). Moreover, the specific charge values yielded by the two methods are approximately the same and very close together.

  6. Modeling Long-Term Trends in Russet Burbank Potato Growth and Development in Wisconsin

    Directory of Open Access Journals (Sweden)

    David Curwen

    2012-03-01

    Full Text Available Improving understanding and prediction of the potato (Solanum tuberosum tuber size over the growing season is important due to its effects on crop price and marketing. Several models have been proposed to describe potato growth and development, but are based on short-term data and have little use for predicting yields or in-season management decisions. This analysis uses long-term data collected from 1979 to 1993 in central Wisconsin to describe growth and development of the Russet Burbank potato variety. This paper describes average number of potato tubers per plant and tuber length as influenced by thermal time and stem number per plant over 14 years. For each plant variable, data analysis uses multivariate techniques to fit a hierarchical logistic model with parameters potentially depending on stem number per plant. Analysis finds that the average number of potato tubers and average tuber length were affected by thermal time and stem number per plant. Estimated models are biologically relevant, provide an understanding of seasonal thermal variability and stem number per plant effects on average tuber set and growth, and can be used to describe yearly variation in average potato growth and development. Increased understanding of potato growth in response to thermal time and stem number per plant can improve management recommendations and predictions of crop economic value.

  7. Coupled Aerosol-Chemistry-Climate Twentieth-Century Transient Model Investigation: Trends in Short-Lived Species and Climate Responses

    Science.gov (United States)

    Koch, Dorothy; Bauer, Susanne E.; Del Genio, Anthony; Faluvegi, Greg; McConnell, Joseph R.; Menon, Surabi; Miller, Ronald L.; Rind, David; Ruedy, Reto; Schmidt, Gavin A.; Shindell, Drew

    2011-01-01

    The authors simulate transient twentieth-century climate in the Goddard Institute for Space Studies (GISS) GCM, with aerosol and ozone chemistry fully coupled to one another and to climate including a full dynamic ocean. Aerosols include sulfate, black carbon (BC), organic carbon, nitrate, sea salt, and dust. Direct and BC snow-albedo radiative effects are included. Model BC and sulfur trends agree fairly well with records from Greenland and European ice cores and with sulfur deposition in North America; however, the model underestimates the sulfur decline at the end of the century in Greenland. Global BC effects peak early in the century (1940s); afterward the BC effects decrease at high latitudes of the Northern Hemisphere but continue to increase at lower latitudes. The largest increase in aerosol optical depth occurs in the middle of the century (1940s-80s) when sulfate forcing peaks and causes global dimming. After this, aerosols decrease in eastern North America and northern Eurasia leading to regional positive forcing changes and brightening. These surface forcing changes have the correct trend but are too weak. Over the century, the net aerosol direct effect is -0.41 Watts per square meter, the BC-albedo effect is -0.02 Watts per square meter, and the net ozone forcing is +0.24 Watts per square meter. The model polar stratospheric ozone depletion develops, beginning in the 1970s. Concurrently, the sea salt load and negative radiative flux increase over the oceans around Antarctica. Net warming over the century is modeled fairly well; however, the model fails to capture the dynamics of the observedmidcentury cooling followed by the late century warming.Over the century, 20% of Arctic warming and snow ice cover loss is attributed to the BC albedo effect. However, the decrease in this effect at the end of the century contributes to Arctic cooling. To test the climate responses to sulfate and BC pollution, two experiments were branched from 1970 that removed

  8. Process-based morphodynamic modeling of the Yangtze Estuary at a decadal timescale: Controls on estuarine evolution and future trends

    Science.gov (United States)

    Luan, Hua Long; Ding, Ping Xing; Wang, Zheng Bing; Ge, Jian Zhong

    2017-08-01

    Understanding the decadal morphodynamic evolution of estuaries and deltas and their controls is of vital importance regarding management for estuarine function and sustainable development. This work addresses this issue by applying a process-based model system (Delft3D) to hindcast and then forecast the morphodynamic evolution of the Yangtze Estuary at a decadal timescale. Forced by the river and tides, the model considers sand-mud mixture and the variations of river water discharge and sediment discharge. The morphodynamic model is validated against three periods, i.e., an accretion period (1958-1978), an erosion period (1986-1997) and a recent accretion period with human activities (2002 - 2010). Model results show good performance with respect to spatial erosion and deposition patterns, sediment volume changes, and hypsometry curves. The model reveals quite different behaviors for mud transport between the dry and wet seasons, which is subject to the prescription of river boundary conditions and bed composition. We define six scenarios to project evolution to the year 2030 under decreased river inputs and increased relative sea level. The simulations reveal that overwhelming amount of erosion will likely occur in the inner and mouth bar area of the estuary. Particularly, the mouth zone will shift from net deposition before 2010 to net erosion by 2030, mainly because of decreasing sediment supply. Changes in water discharge have minor effects on the projected trend. Net erosion will be considerable when the sediment supply is extremely low (100 Mt yr- 1) due to the abundance of erodible modern sediment in the Yangtze Estuary. Erosion within the mouth bar area may be unexpected, including the deepening of the tidal inlet at East Chongming mudflat and the formation of a flood channel on the seaward side of Jiuduansha Shoal. Overall, the model results provide valuable information for sustainable delta management under changing conditions for both the Yangtze system

  9. Modelling of seasonal and long-term trends in lake salinity in southwestern Victoria, Australia.

    Science.gov (United States)

    Yihdego, Yohannes; Webb, John

    2012-12-15

    In southwestern Victoria a large number of lakes are scattered across the volcanic plains; many have problems with increasing salinity. To identify the hydrologic components behind this problem, three lakes, Burrumbeet, Linlithgow and Buninjon, were selected for detailed water and salt budget modelling using monthly values of rainfall, evaporation, surface inflow and outflow, and groundwater inflow and outflow (using the new modified difference method developed in this study). On average, rainfall begins to exceed evaporation with the onset of winter rainfall in May, so lake levels rise and lake salinities decline. The modelled lakes have become more saline over the last decade, a time of drought with below average rainfall, and all eventually dried out, their salinities rising to very high levels as they shallowed. Lake Burrumbeet is generally much less saline than Lakes Linlithgow and Buninjon, because it has substantial groundwater outflow, probably due to leakage through one or more volcanic necks. This limits the amount of time the lake water is subject to evaporation, and also allows significant salt export. The other lakes do not leak. The modelling indicates that when the lakes dry out, salt is lost from the lake-beds, probably due to wind deflation of salt crusts and leakage into the underlying groundwater. The removal of salt during drying-out phases resets the salinity of the lakes, limiting their ability to become more saline with time. Drying-out phases may therefore be essential in preventing the increased salinisation of lakes and wetland environments across the volcanic plains. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. Trends in biomedical engineering: focus on Patient Specific Modeling and Life Support Systems.

    Science.gov (United States)

    Dubini, Gabriele; Ambrosi, Davide; Bagnoli, Paola; Boschetti, Federica; Caiani, Enrico G; Chiastra, Claudio; Conti, Carlo A; Corsini, Chiara; Costantino, Maria Laura; D'Angelo, Carlo; Formaggia, Luca; Fumero, Roberto; Gastaldi, Dario; Migliavacca, Francesco; Morlacchi, Stefano; Nobile, Fabio; Pennati, Giancarlo; Petrini, Lorenza; Quarteroni, Alfio; Redaelli, Alberto; Stevanella, Marco; Veneziani, Alessandro; Vergara, Christian; Votta, Emiliano; Wu, Wei; Zunino, Paolo

    2011-01-01

    Over the last twenty years major advancements have taken place in the design of medical devices and personalized therapies. They have paralleled the impressive evolution of three-dimensional, non invasive, medical imaging techniques and have been continuously fuelled by increasing computing power and the emergence of novel and sophisticated software tools. This paper aims to showcase a number of major contributions to the advancements of modeling of surgical and interventional procedures and to the design of life support systems. The selected examples will span from pediatric cardiac surgery procedures to valve and ventricle repair techniques, from stent design and endovascular procedures to life support systems and innovative ventilation techniques.

  11. Modelling subsurface hydrology in Mediterranean regions to investigate spatial and temporal trends

    Science.gov (United States)

    Evans, Cristina M.; Singer, Michael B.; Dritschel, David G.

    2016-04-01

    Mediterranean environments have highly variable hydrologic regimes characterised by two distinct seasons: cold/wet and warm/dry. Understanding how this climate is expressed in subsurface hydrology is a basis for the effective management of water as a resource. Riparian systems are particularly complex due to the contribution of both infiltrating precipitation and subsurface hyporheic flows. Therefore a more in-depth investigation of subsurface hydrology is required to understand riparian corridors. Numerical models can be used to simulate soil-water distribution and exchange. We have built-on existing theory of flow through porous media to create a physically-based, river- and climate-driven numerical model of hyporheic flow and infiltration/evaporation that predicts the water content at any depth in a soil column and at any distance from the river channel. The model incorporates the Richards equation - describing the vertical infiltration and diffusion of water in porous media - and the Boussinesq equation, which simulates the horizontal evolution of the water-table (hyporheic flow). These equations have been fully coupled to reflect the interplay between the saturated and unsaturated zones. The model produces a daily time-series of water table elevations and vertical soil moisture patterns in the vadose zones to allow us to study the hydrological partitioning and soil-moisture distribution in a given soil profile. We apply this tool to Mediterranean regions over a number of years to explore seasonal and inter-annual hydrological patterns. Two sites along the Rhône River in France with distinct climates allow us to investigate the impact of riverine and climate functioning. In particular we assess the impact of distance from the river channel and exposure to warmer and dryer conditions. Finally, the temporal legacy of extreme events such as floods and droughts is considered within the context of the impact to riparian vegetation. These comparisons will resolve

  12. MONITORING AND MODELING OF THE MAIN TRENDS IN THE DEVELOPMENT OF SCIENTIFIC ACTIVITY IN RUSSIA

    Directory of Open Access Journals (Sweden)

    Marina U. Archipova

    2014-01-01

    Full Text Available This article is devoted to monitoring of the scientific sphere in Russia in comparison to thedeveloped countries. Attention is paid especially to analysis of interrelation between scientifi c researches costs and the results of scientifi c activity,as well as to the modeling of innovative activityin Russia on the based on the systems of therecursive simultaneous equations. The conductedresearch allows to follow the diffusion of scientific knowledge and their influence on innovative activity in the country.

  13. The Trend-in-trend Research Design for Causal Inference.

    Science.gov (United States)

    Ji, Xinyao; Small, Dylan S; Leonard, Charles E; Hennessy, Sean

    2017-07-01

    Cohort studies can be biased by unmeasured confounding. We propose a hybrid ecologic-epidemiologic design called the trend-in-trend design, which requires a strong time trend in exposure, but is unbiased unless there are unmeasured factors affecting outcome for which there are time trends in prevalence that are correlated with time trends in exposure across strata with different exposure trends. Thus, the conditions under which the trend-in-trend study is biased are a subset of those under which a cohort study is biased. The trend-in-trend design first divides the study population into strata based on the cumulative probability of exposure given covariates, which effectively stratifies on time trend in exposure, provided there is a trend. Next, a covariates-free maximum likelihood model estimates the odds ratio (OR) using data on exposure prevalence and outcome frequency within cumulative probability of exposure strata, across multiple periods. In simulations, the trend-in-trend design produced ORs with negligible bias in the presence of unmeasured confounding. In empiric applications, trend-in-trend reproduced the known positive association between rofecoxib and myocardial infarction (observed OR: 1.2, 95% confidence interval: 1.1, 1.4), and known null associations between rofecoxib and severe hypoglycemia (OR = 1.1 [0.92, 1.3]) and nonvertebral fracture (OR = 0.84 [0.64, 1.1]). The trend-in-trend method may be useful in settings where there is a strong time trend in exposure, such as a newly approved drug or other medical intervention. See video abstract at, http://links.lww.com/EDE/B178.

  14. Modelled present and future thaw lake area expansion/contraction trends throughout the continuous permafrost zone

    Directory of Open Access Journals (Sweden)

    Y. Mi

    2014-07-01

    Full Text Available Thaw lakes and drained lake basins are a dominant feature of Arctic lowlands. Thaw lakes are a source of the greenhouse gas methane (CH4, which is produced under anaerobic conditions, while drained lake basins are carbon sinks due to sedimentation. Besides feedbacks on climate, the development of thaw lakes due to the melt-out of ground ice and subsequent ground subsidence, can have significant impacts on the regional morphology, hydrology, geophysics and biogehemistry. Permafrost degradation as a result of climate warming, which is proceeding considerably faster in high latitude regions than the global average, could lead to either an increases in lake area due to lake expansion, or decrease due to lake drainage. However, which process will dominate is elusive. Therefore understanding thaw lake dynamics and quantifying the feedbacks related to thaw lake expansion and contraction are urgent questions to solve. We apply a stochastic model, THAWLAKE, on four representative Arctic sites, to reproduce recent lake dynamics (1963–2012 and predict for the future changes under various anticipated climate scenarios. The model simulations of current thaw lake cycles and expansion rates are comparable with data. Future lake expansions are limited by lake drainage. We suggest further improvements in the area of enhancing the hydrology component, and operation on larger scales to gauge the impacts on lacustrine morphology and greenhouse gas emissions.

  15. MODELING OF MODERN TRENDS IN RISKORIENTED AUDIT WITH THE APPLICATION OF BAYES THEOREM

    Directory of Open Access Journals (Sweden)

    Katsko I. A.

    2016-01-01

    Full Text Available There are many ways to improve the decisionmaking process, but, with a big amount of data and complexity of decision-making trees, it's becoming more and more complicated to keep up with the flow of information coming from many spheres of modern life. Therefore, the development of various problemsolving approaches has become an important step in changing the face of existing technological systems. This idea appeared in the work of an American scientist J. Perl who, in 1988, founded a new probabilistic approach to artificial intelligence and developed principles of Bayesian Network. Bayesian Network is a graphical model that represents a set of random variables and their conditional dependencies. In the article, the most valuable parts of the given topic have been reviewed, cognitive maps have been compared with their partial manifestation - Bayesian Network; also, one of the options to practically use such models in the audit field has been analyzed by observing a possible decision-making process of giving a modified or unmodified opinion

  16. ACRIM-gap and TSI trend issue resolved using a surface magnetic flux TSI proxy model

    Science.gov (United States)

    Scafetta, Nicola; Willson, Richard C.

    2009-03-01

    The ACRIM-gap (1989.5-1991.75) continuity dilemma for satellite TSI observations is resolved by bridging the satellite TSI monitoring gap between ACRIM1 and ACRIM2 results with TSI derived from Krivova et al.'s (2007) proxy model based on variations of the surface distribution of solar magnetic flux. `Mixed' versions of ACRIM and PMOD TSI composites are constructed with their composites' original values except for the ACRIM gap, where Krivova modeled TSI is used to connect ACRIM1 and ACRIM2 results. Both `mixed' composites demonstrate a significant TSI increase of 0.033 %/decade between the solar activity minima of 1986 and 1996, comparable to the 0.037 % found in the ACRIM composite. The finding supports the contention of Willson (1997) that the ERBS/ERBE results are flawed by uncorrected degradation during the ACRIM gap and refutes the Nimbus7/ERB ACRIM gap adjustment Fröhlich and Lean (1998) employed in constructing the PMOD.

  17. Development of a time-trend model for analyzing and predicting case-pattern of Lassa fever epidemics in Liberia, 2013-2017.

    Science.gov (United States)

    Olugasa, Babasola O; Odigie, Eugene A; Lawani, Mike; Ojo, Johnson F

    2015-01-01

    The objective was to develop a case-pattern model for Lassa fever (LF) among humans and derive predictors of time-trend point distribution of LF cases in Liberia in view of the prevailing under-reporting and public health challenge posed by the disease in the country. A retrospective 5 years data of LF distribution countrywide among humans were used to train a time-trend model of the disease in Liberia. A time-trend quadratic model was selected due to its goodness-of-fit (R2 = 0.89, and P trend within the Northern County of Nimba. Case specific exponential increase was predicted for the first 2 years (2013-2014) with a geometric increase over the next 3 years (2015-2017) in Nimba County. This paper describes a translational application of the space-time distribution pattern of LF epidemics, 2008-2012 reported in Liberia, on which a predictive model was developed. We proposed a computationally feasible two-stage space-time permutation approach to estimate the time-trend parameters and conduct predictive inference on LF in Liberia.

  18. Nationwide Trends

    Science.gov (United States)

    ... Pain Prevention Recovery Substance Use and SUDs in LGBT Populations Treatment Trends & Statistics Women and Drugs Publications ... of illegal drugs, including marijuana according to federal law, and misuse of prescription drugs. † Binge drinking is ...

  19. Trend analysis from 1970 to 2008 and model evaluation of EDGARv4 global gridded anthropogenic mercury emissions

    Energy Technology Data Exchange (ETDEWEB)

    Muntean, Marilena, E-mail: marilena.muntean@jrc.ec.europa.eu [European Commission, Joint Research Centre, Institute for Environment and Sustainability, Ispra (Italy); Janssens-Maenhout, Greet [European Commission, Joint Research Centre, Institute for Environment and Sustainability, Ispra (Italy); Song, Shaojie; Selin, Noelle E. [Massachusetts Institute of Technology, Cambridge, MA (United States); Olivier, Jos G.J. [PBL Netherlands Environment Assessment Agency, Bilthoven (Netherlands); Guizzardi, Diego [European Commission, Joint Research Centre, Institute for Environment and Sustainability, Ispra (Italy); Maas, Rob [RIVM National Institute for Public Health and Environment, Bilthoven (Netherlands); Dentener, Frank [European Commission, Joint Research Centre, Institute for Environment and Sustainability, Ispra (Italy)

    2014-10-01

    model can generally reproduce both spatial variations and long-term trends in total gaseous mercury concentrations and wet deposition fluxes. - Highlights: • A global mercury emission inventory over the past four decades was established. • The inventory was at the lower range of the UNEP Minamata estimates. • The inventory was evaluated using a global 3-D mercury model GEOS-Chem. • The model reproduced spatial variations and long-term trends.

  20. INVESTIGATION OF PURCHASING TRENDS OF AFTER BIRTH MOTHER AND BABY CARE ASSISTANT SERVICE WITH STRUCTURAL EQUATION MODELS

    Directory of Open Access Journals (Sweden)

    Münevver TURANLI

    2016-01-01

    Full Text Available Aim: The purpose of this study, 25-40 years married, gave birth in the last 5 years or are considering having children according to their answers to the survey on women in a buying trend, identify the factors that affect this trend and create sales and marketing strategy is to show the way for the sector to determine. Method: The research population aged 25-40 are married, have given birth in the last 5 years or so were women who are considering having children. Used in the research literature is very collection tool was created based on the research literature. Questions that we used in our study has been prepared in accordance with the opinion of the assistant nurses working in neonatal hospital care providers. The questionnaire was presented on social networking sites and answers are stored in a virtual environment. Data were analyzed by analysis and structural equation models were tried to be. Results: 173 women participated in the survey; The average age is 30 and 3.5% of primary school graduates, 28.3% graduated from high school or equivalent, 68.2% have graduated from college or higher education. The majority in terms of income level while a good income, have stated that they have a very small portion of the lower income levels. Conclusions: Service organizations that provide services to women’s needs and the expectations are in line with the family financially if it should make a compensation in the direction to exceed the budget.

  1. Estimating Size and Trend of the North Interlake Woodland Caribou Population Using Fecal-DNA and Capture-Recapture Models.

    Science.gov (United States)

    Hettinga, Peter N; Arnason, Arni Neil; Manseau, Micheline; Cross, Dale; Whaley, Kent; Wilson, Paul J

    2012-08-01

    A critical step in recovery efforts for endangered and threatened species is the monitoring of population demographic parameters. As part of these efforts, we evaluated the use of fecal-DNA based capture-recapture methods to estimate population sizes and population rate of change for the North Interlake woodland caribou herd (Rangifer tarandus caribou), Manitoba, Canada. This herd is part of the boreal population of woodland caribou, listed as threatened under the federal Species at Risk Act (2003) and the provincial Manitoba Endangered Species Act (2006). Between 2004 and 2009 (9 surveys), we collected 1,080 fecal samples and identified 180 unique genotypes (102 females and 78 males). We used a robust design survey plan with 2 surveys in most years and analysed the data with Program MARK to estimate encounter rates (p), apparent survival rates (ϕ), rates of population change (λ), and population sizes (N). We estimated these demographic parameters for males and females and for 2 genetic clusters within the North Interlake. The population size estimates were larger for the Lower than the Upper North Interlake area and the proportion of males was lower in the Lower (33%) than the Upper North Interlake (49%). Population rate of change for the entire North Interlake area (2005-2009) using the robust design Pradel model was significantly trends, which correspond to trends observed in other fragmented populations of woodland caribou along the southern part of their range. The results of this study clearly demonstrate the applicability and success of non-invasive genetic sampling in monitoring populations of woodland caribou. © 2012 The Wildlife Society.

  2. Application of the UK foresight obesity model in Ireland: the health and economic consequences of projected obesity trends in Ireland.

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    Laura Keaver

    Full Text Available BACKGROUND: Given the scale of the current obesity epidemic and associated health consequences there has been increasing concern about the economic burden placed on society in terms of direct healthcare costs and indirect societal costs. In the Republic of Ireland these costs were estimated at €1.13 billion for 2009. The total direct healthcare costs for six major obesity related conditions (coronary heart disease & stroke, cancer, hypertension, type 2 diabetes and knee osteoarthritis in the same year were estimated at €2.55 billion. The aim of this research is to project disease burden and direct healthcare costs for these conditions in Ireland to 2030 using the established model developed by the Health Forum (UK for the Foresight: Tackling Obesities project. METHODOLOGY: Routine data sources were used to derive incidence, prevalence, mortality and survival for six conditions as inputs for the model. The model utilises a two stage modelling process to predict future BMI rates, disease prevalence and costs. Stage 1 employs a non-linear multivariate regression model to project BMI trends; stage 2 employs a microsimulation approach to produce longitudinal projections and test the impact of interventions upon future incidence of obesity-related disease. RESULTS: Overweight and obesity are projected to reach levels of 89% and 85% in males and females respectively by 2030. This will result in an increase in the obesity related prevalence of CHD & stroke by 97%, cancers by 61% and type 2 diabetes by 21%. The direct healthcare costs associated with these increases will amount to €5.4 billion by 2030. A 5% reduction in population BMI levels by 2030 is projected to result in €495 million less being spent in obesity-related direct healthcare costs over twenty years. DISCUSSION: These findings have significant implications for policy, highlighting the need for effective strategies to prevent this avoidable health and economic burden.

  3. Trends of HCl, ClONO 2 and HF column abundances from ground-based FTIR measurements in Kiruna (Sweden in comparison with KASIMA model calculations

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    U. Raffalski

    2011-01-01

    Full Text Available Trends of hydrogen chloride (HCl, chlorine nitrate (ClONO2 and hydrogen fluoride (HF column abundances above Kiruna (Northern Sweden, 67.84° N, 20.41° E derived from nearly 14 years (1996–2009 of measurement and model data are presented. The measurements have been performed with a Bruker 120 HR (later Bruker 125 HR Fourier transform infrared (FTIR spectrometer and the model used was KASIMA (KArlsruhe SImulation model of the Middle Atmosphere. To calculate the long-term trends, a linear function combined with an annual cycle was fitted to the data using a least squares method. The precision of the resulting trends was estimated with the so-called bootstrap resampling method. The relative trends were calculated on the basis of the linear fit result on 1 January 2000, 12:00 UTC. For hydrogen fluoride, both model and measurements show a positive trend that seems to decrease in the last few years. This suggests a stabilisation of the HF total column abundance. For the summer data (August to November, the FTIR trend of (+1.25 ± 0.28%/yr agrees within errors with the KASIMA one of (+1.55 ± 0.11%/yr. The trends determined for HCl and ClONO2 are significantly negative over the time period considered here. This corresponds to the expectations because the emission of their precursors (chlorofluorocarbons and hydrochlorofluorocarbons has been restricted in the Montreal Protocol in 1987 and its amendments and adjustments. The relative trend for ClONO2 from the FTIR measurements amounts to (−3.28 ± 0.56%/yr and the one for HCl to (−0.81± 0.23%/yr. KASIMA simulates a weaker decrease: For ClONO2, the result is (−0.90 ± 0.10%/yr and for HCl (−0.17± 0.06%/yr. Part of the difference between measurement and model data can be explained by sampling and the stronger annual cycle indicated by the measurements. There is a factor of about four between the trends of HCl and ClONO2 above Kiruna for both measurement and model data. The absolute values of

  4. Analisis Tingkat Kognitif Uji Kompetensi pada Buku Sekolah Elektronik (BSE Matematika SMP/MTs Kelas VII Kurikulum 2013 Berdasarkan Taksonomi Bloom

    Directory of Open Access Journals (Sweden)

    Nancy Yunita Susanti

    2015-06-01

    Full Text Available Buku teks pelajaran berperan penting dan strategis dalam upaya meningkatkan mutu pendidikan dasar dan menengah. Buku teks dilengkapi dengan soal-soal latihan yang belum terklasifikasi tingkat kognitifnya. Penelitian ini bertujuan untuk mengetahui tingkat kognitif soal uji kompetensi beserta persentase masing-masing tingkat kognitif soal uji kompetensi pada BSE Matematika SMP Kelas VII kurikulum 2013 semester 1 maupun semester 2. Jenis penelitian yang digunakan adalah penelitian deskriptif dengan pendekatan kualitatif. Hasil penelitian dapat disimpulkan bahwa soal uji kompetensi BSE Matematika semester 1 mencakup 9 variasi soal dari 24 variasi soal menurut tingkat kognitif Revisi Taksonomi Bloom. Dari 166 pertanyaan, terdapat 6.6% tingkat C2-faktual; 17% tingkat C2-konseptual; 22% tingkat C2-prosedural; 3% tingkat C3-faktual; 6.6% tingkat C3-konseptual; 28% tingkat C3-prosedural; 1.8% tingkat C4-konseptual; 14% tingkat C4-prosedural; 0.6% tingkat C6-konseptual; dan 0% pertanyaan tingkat yang lainnya. Sedangkan pada BSE Matematika semester 2 mencakup 11 variasi soal. Dari 170 pertanyaan terdapat 0.6% tingkat C1-faktual; 0.6% tingkat C1-konseptual; 2.9% tingkat C2-faktual; 15% tingkat C2-konseptual; 15% tingkat C2-prosedural; 8.2% tingkat C3-konseptual; 30% tingkat C3-prosedural; 4.7% tingkat C4-konseptual; 5.3% tingkat C4-prosedural; 14% tingkat C5-konseptual; 4.1% tingkat C6 konseptual; dan 0% tingkat yang lain.Textbooks have an important and strategic role in improving the quality of primary and secondary education. Textbook comes with practice questions are not yet classified the cognitive level. The aims of this study are determining the level of cognitive matter competency test along with the percentage of each level of cognitive matter competency test on BSE Class VII SMP Math curriculum 2013 1st half and 2nd semester. Type of research is descriptive research with a qualitative approach. It can be concluded that about half of the competency

  5. Measured and modelled trends in European mountain lakes: results of fifteen years of cooperative studies

    Directory of Open Access Journals (Sweden)

    Michela ROGORA

    2004-02-01

    Full Text Available Papers included in this Special Issue of the Journal of Limnology present results of long-term ecological research on mountain lakes throughout Europe. Most of these studies were performed over the last 15 years in the framework of some EU-funded projects, namely AL:PE 1 and 2, MOLAR and EMERGE. These projects together considered a high number of remote lakes in different areas or lake districts in Europe. Central to the projects was the idea that mountain lakes, while subject to the same chemical and biological processes controlling lowland lakes, are more sensitive to any input from their surroundings and can be used as earlywarning indicators of atmospheric pollution and climate change. A first section of this special issue deal with the results of long-term monitoring programmes at selected key-sites. A second section focuse on site-specific and regional applications of an acidification model designed to reconstruct and predict long-term changes in the chemistry of mountain lakes.

  6. Modelling long-term trends in lunar exposure to the Earth's plasmasheet

    Directory of Open Access Journals (Sweden)

    M. Hapgood

    2007-10-01

    Full Text Available This paper shows how the exposure of the Moon to the Earth's plasmasheet is subject to decadal variations due to lunar precession. The latter is a key property of the Moon's apparent orbit around the Earth – the nodes of that orbit precess around the ecliptic, completing one revolution every 18.6 years. This precession is responsible for a number of astronomical phenomena, e.g. the year to year drift of solar and lunar eclipse periods. It also controls the ecliptic latitude at which the Moon crosses the magnetotail and thus the number and duration of lunar encounters with the plasmasheet. This paper presents a detailed model of those encounters and applies it to the period 1960 to 2030. This shows that the total lunar exposure to the plasmasheet will vary from 10 h per month at a minimum of the eighteen-year cycle rising to 40 h per month at the maximum. These variations could have a profound impact on the accumulation of charge due plasmasheet electrons impacting the lunar surface. Thus we should expect the level of lunar surface charging to vary over the eighteen-year cycle. The literature contains reports that support this: several observations made during the cycle maximum of 1994–2000 are attributed to bombardment and charging of the lunar surface by plasmasheet electrons. Thus we conclude that lunar surface charging will vary markedly over an eighteen-year cycle driven by lunar precession. It is important to interpret lunar environment measurements in the context of this cycle and to allow for the cycle when designing equipment for deployment on the lunar surface. This is particularly important in respect of developing plans for robotic exploration on the lunar surface during the next cycle maximum of 2012–2019.

  7. Integrated water assessment and modelling: A bibliometric analysis of trends in the water resource sector

    Science.gov (United States)

    Zare, Fateme; Elsawah, Sondoss; Iwanaga, Takuya; Jakeman, Anthony J.; Pierce, Suzanne A.

    2017-09-01

    There are substantial challenges facing humanity in the water and related sectors and purposeful integration of the disciplines, connected sectors and interest groups is now perceived as essential to address them. This article describes and uses bibliometric analysis techniques to provide quantitative insights into the general landscape of Integrated Water Resource Assessment and Modelling (IWAM) research over the last 45 years. Keywords, terms in titles, abstracts and the full texts are used to distinguish the 13,239 IWAM articles in journals and other non-grey literature. We identify the major journals publishing IWAM research, influential authors through citation counts, as well as the distribution and strength of source countries. Fruitfully, we find that the growth in numbers of such publications has continued to accelerate, and attention to both the biophysical and socioeconomic aspects has also been growing. On the other hand, our analysis strongly indicates that the former continue to dominate, partly by embracing integration with other biophysical sectors related to water - environment, groundwater, ecology, climate change and agriculture. In the social sciences the integration is occurring predominantly through economics, with the others, including law, policy and stakeholder participation, much diminished in comparison. We find there has been increasing attention to management and decision support systems, but a much weaker focus on uncertainty, a pervasive concern whose criticalities must be identified and managed for improving decision making. It would seem that interdisciplinary science still has a long way to go before crucial integration with the non-economic social sciences and uncertainty considerations are achieved more routinely.

  8. Visualization of trace-element zoning in fluorapatite using BSE and CL imaging, and EPMA and μPIXE/μPIGE mapping

    Science.gov (United States)

    Gros, Katarzyna; Słaby, Ewa; Förster, Hans-Jürgen; Michalak, Przemysław P.; Munnik, Frans; Götze, Jens; Rhede, Dieter

    2016-12-01

    In this paper, zonation patterns of trace elements in fluorapatite are discussed that were visualized using four analytical techniques, namely back-scattered electrons (BSE) and cathodoluminescence (CL) imaging, electron probe micro-analysis (EPMA), and micro-proton-induced X-ray/gamma ray emission (μPIXE/μPIGE) mapping. Each method demonstrates the in-grain compositional variations in a slightly different way. Both BSE and CL provide qualitative data, and the internal textures are displayed in most detail. Additionally, CL points to specific elements enriched in certain growth zones. Qualitative EPMA maps show detailed zonation patterns for specific elements (with high spatial resolution), which are in general correspondence with the patterns observed in BSE and CL images. The μPIXE/μPIGE maps are fully quantitative and the detection limits are relatively low compared to EPMA mapping. In present spot measurements μPIXE demonstrates lower detection limits than EPMA, however, the latter could be considerably improved by extending the acquisition times. There is no significant overlap of REE (rare earth elements) peaks in the acquired μPIXE energy spectra, however, when multiple REEs are present with sufficiently high concentrations, peak deconvolution may pose some difficulties. Spatial resolution of μPIXE/μPIGE images is not sufficiently high to reflect minor textural features, which also result from the greater interaction depth of the proton beam. However, major growth zones are distinguishable. Even though each method has their advantages and limitations, when applied together, they provide an almost complete characterization of compositional variability in trace-element-bearing minerals.

  9. Excitation spectra of aromatic molecules within a real-space G W -BSE formalism: Role of self-consistency and vertex corrections

    Science.gov (United States)

    Hung, Linda; da Jornada, Felipe H.; Souto-Casares, Jaime; Chelikowsky, James R.; Louie, Steven G.; Ã-ǧüt, Serdar

    2016-08-01

    We present first-principles calculations on the vertical ionization potentials (IPs), electron affinities (EAs), and singlet excitation energies on an aromatic-molecule test set (benzene, thiophene, 1,2,5-thiadiazole, naphthalene, benzothiazole, and tetrathiafulvalene) within the G W and Bethe-Salpeter equation (BSE) formalisms. Our computational framework, which employs a real-space basis for ground-state and a transition-space basis for excited-state calculations, is well suited for high-accuracy calculations on molecules, as we show by comparing against G0W0 calculations within a plane-wave-basis formalism. We then generalize our framework to test variants of the G W approximation that include a local density approximation (LDA)-derived vertex function (ΓLDA) and quasiparticle-self-consistent (QS) iterations. We find that ΓLDA and quasiparticle self-consistency shift IPs and EAs by roughly the same magnitude, but with opposite sign for IPs and the same sign for EAs. G0W0 and QS G W ΓLDA are more accurate for IPs, while G0W0ΓLDA and QS G W are best for EAs. For optical excitations, we find that perturbative G W -BSE underestimates the singlet excitation energy, while self-consistent G W -BSE results in good agreement with previous best-estimate values for both valence and Rydberg excitations. Finally, our work suggests that a hybrid approach, in which G0W0 energies are used for occupied orbitals and G0W0ΓLDA for unoccupied orbitals, also yields optical excitation energies in good agreement with experiment but at a smaller computational cost.

  10. Two-warehouse partial backlogging inventory model for deteriorating items with linear trend in demand under inflationary conditions

    Science.gov (United States)

    Jaggi, Chandra K.; Khanna, Aditi; Verma, Priyanka

    2011-07-01

    In today's business transactions, there are various reasons, namely, bulk purchase discounts, re-ordering costs, seasonality of products, inflation induced demand, etc., which force the buyer to order more than the warehouse capacity. Such situations call for additional storage space to store the excess units purchased. This additional storage space is typically a rented warehouse. Inflation plays a very interesting and significant role here: It increases the cost of goods. To safeguard from the rising prices, during the inflation regime, the organisation prefers to keep a higher inventory, thereby increasing the aggregate demand. This additional inventory needs additional storage space, which is facilitated by a rented warehouse. Ignoring the effects of the time value of money and inflation might yield misleading results. In this study, a two-warehouse inventory model with linear trend in demand under inflationary conditions having different rates of deterioration has been developed. Shortages at the owned warehouse are also allowed subject to partial backlogging. The solution methodology provided in the model helps to decide on the feasibility of renting a warehouse. Finally, findings have been illustrated with the help of numerical examples. Comprehensive sensitivity analysis has also been provided.

  11. How well do environmental archives of atmospheric mercury deposition in the Arctic reproduce rates and trends depicted by atmospheric models and measurements?

    Science.gov (United States)

    Goodsite, M E; Outridge, P M; Christensen, J H; Dastoor, A; Muir, D; Travnikov, O; Wilson, S

    2013-05-01

    This review compares the reconstruction of atmospheric Hg deposition rates and historical trends over recent decades in the Arctic, inferred from Hg profiles in natural archives such as lake and marine sediments, peat bogs and glacial firn (permanent snowpack), against those predicted by three state-of-the-art atmospheric models based on global Hg emission inventories from 1990 onwards. Model veracity was first tested against atmospheric Hg measurements. Most of the natural archive and atmospheric data came from the Canadian-Greenland sectors of the Arctic, whereas spatial coverage was poor in other regions. In general, for the Canadian-Greenland Arctic, models provided good agreement with atmospheric gaseous elemental Hg (GEM) concentrations and trends measured instrumentally. However, there are few instrumented deposition data with which to test the model estimates of Hg deposition, and these data suggest models over-estimated deposition fluxes under Arctic conditions. Reconstructed GEM data from glacial firn on Greenland Summit showed the best agreement with the known decline in global Hg emissions after about 1980, and were corroborated by archived aerosol filter data from Resolute, Nunavut. The relatively stable or slowly declining firn and model GEM trends after 1990 were also corroborated by real-time instrument measurements at Alert, Nunavut, after 1995. However, Hg fluxes and trends in northern Canadian lake sediments and a southern Greenland peat bog did not exhibit good agreement with model predictions of atmospheric deposition since 1990, the Greenland firn GEM record, direct GEM measurements, or trends in global emissions since 1980. Various explanations are proposed to account for these discrepancies between atmosphere and archives, including problems with the accuracy of archive chronologies, climate-driven changes in Hg transfer rates from air to catchments, waters and subsequently into sediments, and post-depositional diagenesis in peat bogs

  12. Clustering asian and north african countries according to trend of colon and rectum cancer mortality rates: an application of growth mixture models.

    Science.gov (United States)

    Zayeri, Farid; Sheidaei, Ali; Mansouri, Anita

    2015-01-01

    Colorectal cancer is the second most common cause of cancer death with half a million deaths per year. Incidence and mortality rates have demonstrated notable changes in Asian and African countries during the last few decades. In this study, we first aimed to determine the trend of colorectal cancer mortality rate in each Institute for Health Metrics and Evaluation (IHME) region, and then re-classify them to find more homogenous classes. Our study population consisted of 52 countries of Asia and North Africa in six IHME pre-defined regions for both genders and age-standardized groups from 1990 to 2010.We first applied simple growth models for pre-defined IHME regions to estimate the intercepts and slopes of mortality rate trends. Then, we clustered the 52 described countries using the latent growth mixture modeling approach for classifying them based on their colorectal mortality rates over time. Statistical analysis revealed that males and people in high income Asia pacific and East Asia countries were at greater risk of death from colon and rectum cancer. In addition, South Asia region had the lowest rates of mortality due to this cancer. Simple growth modeling showed that majority of IHME regions had decreasing trend in mortality rate of colorectal cancer. However, re-classification these countries based on their mortality trend using the latent growth mixture model resulted in more homogeneous classes according to colorectal mortality trend. In general, our statistical analyses showed that most Asian and North African countries had upward trend in their colorectal cancer mortality. We therefore urge the health policy makers in these countries to evaluate the causes of growing mortality and study the interventional programs of successful countries in managing the consequences of this cancer.

  13. A model of proteostatic energy cost and its use in analysis of proteome trends and sequence evolution.

    Directory of Open Access Journals (Sweden)

    Kasper P Kepp

    Full Text Available A model of proteome-associated chemical energetic costs of cells is derived from protein-turnover kinetics and protein folding. Minimization of the proteostatic maintenance cost can explain a range of trends of proteomes and combines both protein function, stability, size, proteostatic cost, temperature, resource availability, and turnover rates in one simple framework. We then explore the ansatz that the chemical energy remaining after proteostatic maintenance is available for reproduction (or cell division and thus, proportional to organism fitness. Selection for lower proteostatic costs is then shown to be significant vs. typical effective population sizes of yeast. The model explains and quantifies evolutionary conservation of highly abundant proteins as arising both from functional mutations and from changes in other properties such as stability, cost, or turnover rates. We show that typical hypomorphic mutations can be selected against due to increased cost of compensatory protein expression (both in the mutated gene and in related genes, i.e. epistasis rather than compromised function itself, although this compensation depends on the protein's importance. Such mutations exhibit larger selective disadvantage in abundant, large, synthetically costly, and/or short-lived proteins. Selection against increased turnover costs of less stable proteins rather than misfolding toxicity per se can explain equilibrium protein stability distributions, in agreement with recent findings in E. coli. The proteostatic selection pressure is stronger at low metabolic rates (i.e. scarce environments and in hot habitats, explaining proteome adaptations towards rough environments as a question of energy. The model may also explain several trade-offs observed in protein evolution and suggests how protein properties can coevolve to maintain low proteostatic cost.

  14. Estimating decades-long trends in petroleum field energy return on investment (EROI) with an engineering-based model.

    Science.gov (United States)

    Tripathi, Vinay S; Brandt, Adam R

    2017-01-01

    This paper estimates changes in the energy return on investment (EROI) for five large petroleum fields over time using the Oil Production Greenhouse Gas Emissions Estimator (OPGEE). The modeled fields include Cantarell (Mexico), Forties (U.K.), Midway-Sunset (U.S.), Prudhoe Bay (U.S.), and Wilmington (U.S.). Data on field properties and production/processing parameters were obtained from a combination of government and technical literature sources. Key areas of uncertainty include details of the oil and gas surface processing schemes. We aim to explore how long-term trends in depletion at major petroleum fields change the effective energetic productivity of petroleum extraction. Four EROI ratios are estimated for each field as follows: The net energy ratio (NER) and external energy ratio (EER) are calculated, each using two measures of energy outputs, (1) oil-only and (2) all energy outputs. In all cases, engineering estimates of inputs are used rather than expenditure-based estimates (including off-site indirect energy use and embodied energy). All fields display significant declines in NER over the modeling period driven by a combination of (1) reduced petroleum production and (2) increased energy expenditures on recovery methods such as the injection of water, steam, or gas. The fields studied had NER reductions ranging from 46% to 88% over the modeling periods (accounting for all energy outputs). The reasons for declines in EROI differ by field. Midway-Sunset experienced a 5-fold increase in steam injected per barrel of oil produced. In contrast, Prudhoe Bay has experienced nearly a 30-fold increase in amount of gas processed and reinjected per unit of oil produced. In contrast, EER estimates are subject to greater variability and uncertainty due to the relatively small magnitude of external energy investments in most cases.

  15. Computing DNA duplex instability profiles efficiently with a two-state model: trends of promoters and binding sites

    Directory of Open Access Journals (Sweden)

    Rapti Zoi

    2010-12-01

    Full Text Available Abstract Background DNA instability profiles have been used recently for predicting the transcriptional start site and the location of core promoters, and to gain insight into promoter action. It was also shown that the use of these profiles can significantly improve the performance of motif finding programs. Results In this work we introduce a new method for computing DNA instability profiles. The model that we use is a modified Ising-type model and it is implemented via statistical mechanics. Our linear time algorithm computes the profile of a 10,000 base-pair long sequence in less than one second. The method we use also allows the computation of the probability that several consecutive bases are unpaired simultaneously. This is a feature that is not available in other linear-time algorithms. We use the model to compare the thermodynamic trends of promoter sequences of several genomes. In addition, we report results that associate the location of local extrema in the instability profiles with the presence of core promoter elements at these locations and with the location of the transcription start sites (TSS. We also analyzed the instability scores of binding sites of several human core promoter elements. We show that the instability scores of functional binding sites of a given core promoter element are significantly different than the scores of sites with the same motif occurring outside the functional range (relative to the TSS. Conclusions The time efficiency of the algorithm and its genome-wide applications makes this work of broad interest to scientists interested in transcriptional regulation, motif discovery, and comparative genomics.

  16. Multistate models for comparing trends in hospitalizations among young adult survivors of colorectal cancer and matched controls

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    Sutradhar Rinku

    2012-10-01

    Full Text Available Abstract Background Over the past years, the incidence of colorectal cancer has been increasing among young adults. A large percentage of these patients live at least 5 years after diagnosis, but it is unknown whether their rate of hospitalizations after this 5-year mark is comparable to the general population. Methods This is a population-based cohort consisting of 917 young adult survivors diagnosed with colorectal cancer in Ontario from 1992–1999 and 4585 matched cancer-free controls. A multistate model is presented to reflect and compare trends in the hospitalization process among survivors and their matched controls. Results Analyses under a multistate model indicate that the risk of a subsequent hospital admission increases as the number of prior hospitalizations increases. Among patients who are yet to experience a hospitalization, the rate of admission is 3.47 times higher for YAS than controls (95% CI (2.79, 4.31. However, among patients that have experienced one and two hospitalizations, the relative rate of a subsequent admission decreases to 3.03 (95% CI (2.01, 4.56 and 1.90 (95% CI (1.19, 3.03, respectively. Conclusions Young adult survivors of colorectal cancer have an increased risk of experiencing hospitalizations compared to cancer-free controls. However this relative risk decreases as the number of prior hospitalizations increases. The multistate approach is able to use information on the timing of hospitalizations and answer questions that standard Poisson and Negative Binomial models are unable to address.

  17. Modeling and managing urban water demand through smart meters: Benefits and challenges from current research and emerging trends

    Science.gov (United States)

    Cominola, A.; Giuliani, M.; Castelletti, A.; Piga, D.; Rizzoli, A. E.

    2015-12-01

    Urban population growth, climate and land use change are expected to boost residential water demand in urban contexts in the next decades. In such a context, developing suitable demand-side management strategies is essential to meet future water demands, pursue water savings, and reduce the costs for water utilities. Yet, the effectiveness of water demand management strategies (WDMS) relies on our understanding of water consumers' behavior, their consumption habits, and the water use drivers. While low spatial and temporal resolution water consumption data, as traditionally gathered for billing purposes, hardly support this understanding, the advent of high-resolution, smart metering technologies allowed for quasi real-time monitoring water consumption at the single household level. This, in turn, is advancing our ability in characterizing consumers' behavior, modeling, and designing user-oriented residential water demand management strategies. Several water smart metering programs have been rolled-out in the last two decades worldwide, addressing one or more of the following water demand management phases: (i) data gathering, (ii) water end-uses characterization, (iii) user modeling, (iv) design and implementation of personalized WDMS. Moreover, the number of research studies in this domain is quickly increasing and big economic investments are currently being devoted worldwide to smart metering programs. With this work, we contribute the first comprehensive review of more than 100 experiences in the field of residential water demand modeling and management, and we propose a general framework for their classification. We revise consolidated practices, identify emerging trends and highlight the challenges and opportunities for future developments given by the use of smart meters advancing residential water demand management. Our analysis of the status quo of smart urban water demand management research and market constitutes a structured collection of information

  18. A high resolution model of linear trend in mass variations from DMT-2: Added value of accounting for coloured noise in GRACE data

    Science.gov (United States)

    Farahani, Hassan H.; Ditmar, Pavel; Inácio, Pedro; Didova, Olga; Gunter, Brian; Klees, Roland; Guo, Xiang; Guo, Jing; Sun, Yu; Liu, Xianglin; Zhao, Qile; Riva, Riccardo

    2017-01-01

    We present a high resolution model of the linear trend in the Earth's mass variations based on DMT-2 (Delft Mass Transport model, release 2). DMT-2 was produced primarily from K-Band Ranging (KBR) data of the Gravity Recovery And Climate Experiment (GRACE). It comprises a time series of monthly solutions complete to spherical harmonic degree 120. A novel feature in its production was the accurate computation and incorporation of stochastic properties of coloured noise when processing KBR data. The unconstrained DMT-2 monthly solutions are used to estimate the linear trend together with a bias, as well as annual and semi-annual sinusoidal terms. The linear term is further processed with an anisotropic Wiener filter, which uses full noise and signal covariance matrices. Given the fact that noise in an unconstrained model of the trend is reduced substantially as compared to monthly solutions, the Wiener filter associated with the trend is much less aggressive compared to a Wiener filter applied to monthly solutions. Consequently, the trend estimate shows an enhanced spatial resolution. It allows signals in relatively small water bodies, such as Aral sea and Ladoga lake, to be detected. Over the ice sheets, it allows for a clear identification of signals associated with some outlet glaciers or their groups. We compare the obtained trend estimate with the ones from the CSR-RL05 model using (i) the same approach based on monthly noise covariance matrices and (ii) a commonly-used approach based on the DDK-filtered monthly solutions. We use satellite altimetry data as independent control data. The comparison demonstrates a high spatial resolution of the DMT-2 linear trend. We link this to the usage of high-accuracy monthly noise covariance matrices, which is due to an accurate computation and incorporation of coloured noise when processing KBR data. A preliminary comparison of the linear trend based on DMT-2 with that computed from GSFC_global_mascons_v01 reveals, among

  19. Removing Regional Trends in Microgravity in Complex Environments: Testing on 3D Model and Field Investigations in the Eastern Dead Sea Coast (Jordan

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    A. Al-Zoubi

    2013-01-01

    Full Text Available Microgravity investigations are now recognized as a powerful tool for subsurface imaging and especially for the localization of underground karsts. However numerous natural (geological, technical, and environmental factors interfere with microgravity survey processing and interpretation. One of natural factors that causes the most disturbance in complex geological environments is the influence of regional trends. In the Dead Sea coastal areas the influence of regional trends can exceed residual gravity effects by some tenfold. Many widely applied methods are unable to remove regional trends with sufficient accuracy. We tested number of transformation methods (including computing gravity field derivatives, self-adjusting and adaptive filtering, Fourier series, wavelet, and other procedures on a 3D model (complicated by randomly distributed noise, and field investigations were carried out in Ghor Al-Haditha (the eastern side of the Dead Sea in Jordan. We show that the most effective methods for regional trend removal (at least for the theoretical and field cases here are the bilinear saddle and local polynomial regressions. Application of these methods made it possible to detect the anomalous gravity effect from buried targets in the theoretical model and to extract the local gravity anomaly at the Ghor Al-Haditha site. The local anomaly was utilized for 3D gravity modeling to construct a physical-geological model (PGM.

  20. Spatial patterns of recent Antarctic surface temperature trends and the importance of natural variability: lessons from multiple reconstructions and the CMIP5 models

    Science.gov (United States)

    Sahai, A. K.; Borah, N.; Chattopadhyay, R.; Joseph, S.; Abhilash, S.

    2016-06-01

    The recent annually averaged warming of the Antarctic Peninsula, and of West Antarctica, stands in stark contrast to very small trends over East Antarctica. This asymmetry arises primarily from a highly significant warming of West Antarctica in austral spring and a cooling of East Antarctica in austral autumn. Here we examine whether this East-West asymmetry is a response to anthropogenic climate forcings or a manifestation of natural climate variability. We compare the observed Antarctic surface air temperature trends over two distinct time periods (1960-2005 and 1979-2005), and with those simulated by 40 models participating in Phase 5 of the Coupled Model Intercomparison Project (CMIP5). We find that the observed East-West asymmetry differs substantially between the two periods and, furthermore, that it is completely absent from the forced response seen in the CMIP5 multi-model mean, from which all natural variability is eliminated by the averaging. We also examine the relationship between the Southern Annular mode (SAM) and Antarctic temperature trends, in both models and reanalyses, and again conclude that there is little evidence of anthropogenic SAM-induced driving of the recent temperature trends. These results offer new, compelling evidence pointing to natural climate variability as a key contributor to the recent warming of West Antarctica and of the Peninsula.

  1. Trends in international trade in steam coal. Lessons from the COALMOD-World model; Entwicklungen des internationalen Handels mit Kesselkohle. Lehren aus dem COALMOD-World-Modell

    Energy Technology Data Exchange (ETDEWEB)

    Haftendorn, Clemens; Holz, Franziska; Winke, Tim; Hirschhausen, Christian von [Deutsches Institut fuer Wirtschaftsforschung, Berlin (Germany). Abt. Energie, Verkehr und Umwelt

    2011-12-15

    The global steam coal market has changed dramatically in the last ten years as a result of increasing demand, more flexible terms of trade and intensified exchange transactions. To analyse future market trends the equilibrium model COALMOD-World, which simulates the national and global steam coal market over several periods, is described in this article. Both international maritime trade and the relevant domestic markets are represented for this purpose. The market equilibria determined annually permit regional predictions of the coal quantities traded and the prices up to the year 2030. It is shown in different scenarios that the trend on the steam coal market is heavily dependent on the readiness of the suppliers to invest and the international climate policy. In all scenarios the Asian region will play the most important role in the global steam coal market. China and India in particular will increase their imports on the steam coal market in the next few years, because indigenous deposits are required for the domestic energy market and, in the case of India, diminishing deposits of high-quality coal give rise to an increase in production costs. (orig.)

  2. Model Analysis of the Factors Regulating Trends and Variability of Methane, Carbon Monoxide and OH: 1. Model Validation

    Science.gov (United States)

    Elshorbany, Y. F.; Strode, S.; Wang, J.; Duncan, B.

    2014-01-01

    Methane (CH4) is the second most important anthropogenic greenhouse gas (GHG). Its 100-year global warming potential (GWP) is 25 times larger than that for carbon dioxide. The 100-yr integrated GWP of CH4 is sensitive to changes in OH levels. Methane's atmospheric growth rate was estimated to be more than 10 ppb yr(exp -1) in 1998 but less than zero in 2001, 2004 and 2005 (Kirschke et al., 2013). Since 2006, the CH4 is increasing again. This phenomena is yet not well understood. Oxidation of CH4 by OH is the main loss process, thus affecting the oxidizing capacity of the atmosphere and contributing to the global ozone background. Current models typically use an annual cycle of offline OH fields to simulate CH4. The implemented OH fields in these models are typically tuned so that simulated CH4 growth rates match that measured. For future and climate simulations, the OH tuning technique may not be suitable. In addition, running full chemistry, multi-decadal CH4 simulations is a serious challenge and currently, due to computational intensity, almost impossible.

  3. The interpretation of disease phenotypes to identify TSE strains in mice: characterisation of BSE using PrPSc distribution patterns in the brain

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    Corda Erica

    2012-12-01

    Full Text Available Abstract In individual animals affected by transmissible spongiform encephalopathies, different disease phenotypes can be identified which are attributed to different strains of the agent. In the absence of reliable technology to fully characterise the agent, classification of disease phenotype has been used as a strain typing tool which can be applied in any host. This approach uses standardised data on biological parameters, established for a single host, to allow comparison of different prion sources. Traditionally prion strain characterisation in wild type mice is based on incubation periods and lesion profiles after the stabilisation of the agent into the new host which requires serial passages. Such analysis can take many years, due to prolonged incubation periods. The current study demonstrates that the PrPSc patterns produced by one serial passage in wild type mice of bovine or ovine BSE were consistent, stable and showed minimal and predictable differences from mouse-stabilised reference strains. This biological property makes PrPSc deposition pattern mapping a powerful tool in the identification and definition of TSE strains on primary isolation, making the process of characterisation faster and cheaper than a serial passage protocol. It can be applied to individual mice and therefore it is better suited to identify strain diversity within single inocula in case of co-infections or identify strains in cases where insufficient mice succumb to disease for robust lesion profiles to be constructed. The detailed description presented in this study provides a reference document for identifying BSE in wild type mice.

  4. Results of a modeling workshop concerning economic and environmental trends and concomitant resource management issues in the Mobile Bay area

    Science.gov (United States)

    Hamilton, David B.; Andrews, Austin K.; Auble, Gregor T.; Ellison, Richard A.; Johnson, Richard A.; Roelle, James E.; Staley, Michael J.

    1982-01-01

    Population/Economy Submodels. Finally, a Fish Submodel calculated indicators of habitat quality for finfish and shellfish, utilizing information on water quality and wetlands acreage. The workshop was successful in identifying many of the critical interrelations between components of the Mobile area system. Not all of those interactions, such as the feedback of air quality as a limitation on development, could be incorporated into the workshop model because of the model's broad spatial scale and because of uncertainties or data gaps. Thus, the value of the modeling workshop was in the areas outlines below, rather than in the predictive power of the initial model developed at the workshop. First, participants developed a holistic perspective on the interactions which will determine future economic and environmental trends within the Mobile Bay area. Potential environmental consequences and limitations to grown identified at the workshop included: shoreline and water access; water quality of Mobile Bay; finfish and shellfish habitat quality with respect to dissolved oxygen and coliforms; air quality; and acreage of critical wetland habitat. Second, the model's requirements for specific, quantitative information stimulated supporting analyses, such as economic input-output calculations, which provide additional insight into the Mobile Bay area system. Third, the perspective of the Mobile area as an interacting system was developed in an open, cooperative forum which my provide a foundation for conflict resolution based on common understanding. Finally, the identification of model limitations and uncertainties should be useful in guiding the efficient allocation of future research effort.

  5. Predicting of Trend of Hemoglobin A1c in Type 2 Diabetes: A Longitudinal Linear Mixed Model

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    Elahe Kazemi

    2014-01-01

    Conclusions: The present study shows that regular visits of diabetic patients as well as controlling blood pressure, lipid profile, and weight loss can improve the trend of HbA1c levels during the time.

  6. Temporal trend of the snow-related variables in Sierra Nevada in the last years: An analysis combining Earth Observation and hydrological modelling

    Science.gov (United States)

    Pérez-Luque, Antonio J.; Herrero, Javier; Bonet, Francisco J.; Pérez-Pérez, Ramón

    2016-04-01

    Climate change is causing declines in snow-cover extent and duration in European mountain ranges. This is especially important in Mediterranean mountain ranges where the observed trends towards precipitation and higher temperatures can provoke problems of water scarcity. In this work, we analyzed temporal trends (2000 to 2014) of snow-related variables obtained from satellite and modelling data in Sierra Nevada, a Mediterranean high-mountain range located in Southern Spain, at 37°N. Snow cover indicators (snow-cover duration, snow-cover onset dates and snow-cover melting dates) were obtained by processing images of MOD10A2 MODIS product using an automated workflow. Precipitation data were obtained using WiMMed, a complete and fully distributed hydrological model that is used to map the annual rainfall and snowfall with a resolution of 30x30 m over the whole study area. It uses expert algorithms to interpolate precipitation and temperature at an hourly scale, and simulates partition of precipitation into snowfall with several methods. For each snow-related indicator (snow-covers and snowfall), a trend analysis was applied at the MODIS pixel scale during the study period (2000-2014). We applied Mann-Kendall test and Theil-Sen slope estimation in each of the pixels comprising Sierra Nevada. The trend analysis assesses the intensity, magnitude and degree of statistical significance during the period analysed. The spatial pattern of these trends was explored according to elevation ranges. Finally, we explored the relationship between trends of snow-cover related indicators and precipitation trends. Our results show that snow-cover has undergone significant changes in the last 14 years. 80 % of the pixels covering Sierra Nevada showed a negative trend in the duration of snow-cover. We also observed a delay in the snow-cover onset date (68.03 % pixels showing a positive trend in the snow-cover onset date) and an advance in the melt date (80.72 % of pixels followed a

  7. Analysing recent socioeconomic trends in coronary heart disease mortality in England, 2000-2007: a population modelling study.

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    Madhavi Bajekal

    Full Text Available BACKGROUND: Coronary heart disease (CHD mortality in England fell by approximately 6% every year between 2000 and 2007. However, rates fell differentially between social groups with inequalities actually widening. We sought to describe the extent to which this reduction in CHD mortality was attributable to changes in either levels of risk factors or treatment uptake, both across and within socioeconomic groups. METHODS AND FINDINGS: A widely used and replicated epidemiological model was used to synthesise estimates stratified by age, gender, and area deprivation quintiles for the English population aged 25 and older between 2000 and 2007. Mortality rates fell, with approximately 38,000 fewer CHD deaths in 2007. The model explained about 86% (95% uncertainty interval: 65%-107% of this mortality fall. Decreases in major cardiovascular risk factors contributed approximately 34% (21%-47% to the overall decline in CHD mortality: ranging from about 44% (31%-61% in the most deprived to 29% (16%-42% in the most affluent quintile. The biggest contribution came from a substantial fall in systolic blood pressure in the population not on hypertension medication (29%; 18%-40%; more so in deprived (37% than in affluent (25% areas. Other risk factor contributions were relatively modest across all social groups: total cholesterol (6%, smoking (3%, and physical activity (2%. Furthermore, these benefits were partly negated by mortality increases attributable to rises in body mass index and diabetes (-9%; -17% to -3%, particularly in more deprived quintiles. Treatments accounted for approximately 52% (40%-70% of the mortality decline, equitably distributed across all social groups. Lipid reduction (14%, chronic angina treatment (13%, and secondary prevention (11% made the largest medical contributions. CONCLUSIONS: The model suggests that approximately half the recent CHD mortality fall in England was attributable to improved treatment uptake. This benefit

  8. Effects of parental hypertension on longitudinal trends in blood pressure and plasma metabolic profile: mixed-effects model analysis.

    Science.gov (United States)

    Mitsumata, Kaneto; Saitoh, Shigeyuki; Ohnishi, Hirofumi; Akasaka, Hiroshi; Miura, Tetsuji

    2012-11-01

    The mechanism underlying the association of parental hypertension with cardiovascular events in offspring remains unclear. In this study, the effects of parental hypertension on longitudinal trends of blood pressure and metabolic parameters were examined by mixed-effects model analysis. From 1977 to 2006, 5198 subjects participated in the Tanno-Sobetsu Study, and we selected 2607 subjects (1095 men and 1512 women) for whom data on parental history of hypertension were available. In both men and women with and without parental hypertension, systolic blood pressure and fasting blood glucose levels consistently increased from the third to eighth decades of life, whereas diastolic blood pressure and serum triglyceride levels followed biphasic (inverted U shape) time courses during that period. However, the relationships between the parameters and age were significantly shifted upward (by ≈5.3 mm Hg in systolic blood pressure, 2.8 mm Hg in diastolic blood pressure, 0.30 mmol/L in blood glucose, and 0.09 mmol/L in triglyceride) in the group with parental hypertension compared with those in the group without pare