scholarly journals Investigating the probability of establishment of Zika virus and detection through mosquito surveillance under different temperature conditions

2018 ◽  
Author(s):  
Rebecca C. Christofferson
Keyword(s):  
Experimental Data ◽  
Zika Virus ◽  
Probability Of Detection ◽  
Tropical Regions ◽  
Temperature Conditions ◽  
Significant Difference ◽  
Establishment Potential ◽  
Surveillance Programs ◽  
Successful Establishment ◽  
Incubation Temperatures

AbstractBecause of the increasing threat that Zika virus (ZIKV) poses to extra-tropical regions due to increased global travel, there is a need for better understanding of the effect(s) of temperature on the establishment potential of ZIKV within these subtropical, temperate, and/or seasonal Ae. aegypti populations. The first step to determining risk establishment of ZIKV in these regions is to assess ZIKV’s ability to infect mosquitoes at less tropical temperatures, and thus be detected through common surveillance programs. To that end, the effect of two rearing temperatures (RT) and extrinsic incubation temperatures (EIT) on infection and dissemination rates was evaluated, as well as the interactions of such. Total, there were four combinations (RT24-EIT24, RT24-DEI28, RT28-EIT24, RT28- EIT28). Further, a stochastic SEIR framework was adapted to determine whether observed data could lead to differential success of establishment of ZIKV in naive mosquito populations. There was no consistent pattern in significant differences found across treatments for either infection or dissemination rates (p>0.05), where only a significant difference was found in infection rates between RT24- EIT24 (44%) and RT28-EIT24(82.6%). Across all temperature conditions, the model predicted between a 77.3% and 93.1% chance of successful establishment of ZIKV in naive mosquito populations under model assumptions. Further, the model predicted between 4.1% and 46.7% chance of at least one mosquito developing a disseminated infection, depending on temperature conditions, despite no significant differences in the experimental data. These results indicate that 1) there is no straightforward relationship between RT, EIT, and infection/dissemination rates for ZIKV, similar to what has been reported for DENV, 2) in more temperate climates, ZIKV may still have the ability to establish in populations of Ae. aegypti, and 3) despite a lack of statistical differences in observed experimental data, model predictions indicate that the interplay of rearing and extrinsic incubation temperatures may still alter the kinetics of ZIKV within the mosquito enough to affect numbers of infected/disseminated mosquitoes and the associated probability of detection through surveillance programs.

EPR spectra and defect states in glasses of the GexS100-x system

1982 ◽  
Vol 47 (7) ◽  
pp. 1787-1793 ◽  
Author(s):  
Miloslav Frumar ◽  
Gustáv Plesch ◽  
Eva Černošková ◽  
Václav Černý ◽  
Ladislav Tichý ◽  
...  
Keyword(s):  
Experimental Data ◽  
Epr Spectra ◽  
Defect States ◽  
Composition Region ◽  
Active Defect ◽  
Temperature Conditions ◽  
Defect Centres

Glasses of the GexS100-x system were studied in the region of 30 ⪬ x ⪬ 45. The concept of magnetically active defect centres was employed to account for the EPR spectra of pure samples as well as those doped with silver or iodine, prepared in different temperature conditions. In terms of this concept a consistent interpretation of the experimental data could be given for the composition region applied.

Comparison of soot models for reacting sprays in diesel engine-like conditions

2021 ◽  
pp. 095440702110154
Author(s):  
Pavan Prakash Duvvuri ◽  
Rajesh Kumar Shrivastava ◽  
Sheshadri Sreedhara
Keyword(s):  
Experimental Data ◽  
Volume Fraction ◽  
Soot Volume Fraction ◽  
Modeling Framework ◽  
Aerosol Dynamics ◽  
Significant Difference ◽  
Polycyclic Aromatic ◽  
Order Of Magnitude ◽  
Detailed Kinetics ◽  
Soot Model

Stringent emission legislations and growing health concerns have contributed to the evolution of soot modeling in diesel engines from simple empirical relations to methods involving detailed kinetics and complex aerosol dynamics. In this paper, four different soot models have been evaluated for the high temperature, high pressure combusting dodecane spray cases of engine combustion network (ECN) spray A which mimics engine-relevant conditions. The soot models considered include an empirical, a multistep, a method of moments based, and a discrete sectional method soot model. Two experimental cases with ambient oxygen volume of 21% and 15% have been modeled. A good agreement between simulations and experiments for vapor penetration and heat release rate has been obtained. Quasi-steady soot volume fraction contours for the four soot models have been compared with experiments. Contours of the species and source terms involved in soot modeling have also been compared for a better understanding of soot processes. The empirical soot model results in higher magnitude and spread of soot due to a lack of modeling framework for oxidation through OH species. Among the four models studied, the multistep soot model has been observed to provide the most promising agreement with the experimental data in terms of distribution of soot and location of peak soot volume fraction. Due to a two-way coupling of soot models, the detailed models predict an upstream location for soot as compared to the multi-step soot model which is one way coupled. A significant difference (of an order of magnitude) in the concentration of PAH (polycyclic aromatic hydrocarbons) precursor between multistep and detailed soot models has been observed because of precursor consumption due to the coupling of detailed soot models with chemical kinetics. It is recommended that kinetic schemes, especially those concerning PAH, be validated with experimental data with a kinetics-coupled soot model.

Difference in Critical Reynolds Number Between Hagen-Poiseuille and Plane Poiseuille Flows

2001 ◽  
Author(s):  
Hidesada Kanda
Keyword(s):  
Experimental Data ◽  
Reynolds Number ◽  
Poiseuille Flow ◽  
Average Velocity ◽  
Critical Reynolds Number ◽  
Inlet Section ◽  
Parallel Plates ◽  
Plane Poiseuille Flow ◽  
Contraction Ratio ◽  
Significant Difference

Abstract For plane Poiseuille flow, results of previous investigations were studied, focusing on experimental data on the critical Reynolds number, the entrance length, and the transition length. Consequently, concerning the natural transition, it was confirmed from the experimental data that (i) the transition occurs in the entrance region, (ii) the critical Reynolds number increases as the contraction ratio in the inlet section increases, and (iii) the minimum critical Reynolds number is obtained when the contraction ratio is the smallest or one, and there is no-shaped entrance or straight parallel plates. Its value exists in the neighborhood of 1300, based on the channel height and the average velocity. Although, for Hagen-Poiseuille flow, the minimum critical Reynolds number is approximately 2000, based on the pipe diameter and the average velocity, there seems to be no significant difference in the transition from laminar to turbulent flow between Hagen-Poiseuille flow and plane Poiseuille flow.

scholarly journals Virological and Epidemiological Features of Norovirus Infections in Brazil, 2017–2018

Viruses ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1724
Author(s):  
Sylvia Kahwage Sarmento ◽  
Juliana da Silva Ribeiro de Andrade ◽  
Marize Pereira Miagostovich ◽  
Tulio Machado Fumian
Keyword(s):  
National Level ◽  
Age Groups ◽  
Median Viral Load ◽  
Molecular Surveillance ◽  
Predominant Genotype ◽  
Significant Difference ◽  
Surveillance Programs ◽  
Partial Rdrp ◽  
Stool Samples ◽  
First Time

Noroviruses are considered an important cause of acute gastroenteritis (AGE) across all age groups. Here, we investigated the incidence of norovirus, genotypes circulation, and norovirus shedding in AGE stool samples from outpatients in Brazil. During a two-year period, 1546 AGE stool samples from ten Brazilian states were analyzed by RT-qPCR to detect and quantify GI and GII noroviruses. Positive samples were genotyped by dual sequencing using the ORF1/2 junction region. Overall, we detected norovirus in 32.1% of samples, with a massive predominance of GII viruses (89.1%). We also observed a significant difference between the median viral load of norovirus GI (3.4×105 GC/g of stool) and GII (1.9×107 GC/g). The most affected age group was children aged between 6 and 24 m old, and norovirus infection was detected throughout the year without marked seasonality. Phylogenetic analysis of partial RdRp and VP1 regions identified six and 11 genotype combinations of GI and GII, respectively. GII.4 Sydney[P16] was by far the predominant genotype (47.6%), followed by GII.2[P16], GII.4 Sydney[P31], and GII.6[P7]. We detected, for the first time in Brazil, the intergenogroup recombinant genotype GIX.1[GII.P15]. Our study contributes to the knowledge of norovirus genotypes circulation at the national level, reinforcing the importance of molecular surveillance programs for future vaccine designs.

scholarly journals Anaplasma marginale Superinfection Attributable to Pathogen Strains with Distinct Genomic Backgrounds

2014 ◽  
Vol 82 (12) ◽  
pp. 5286-5292 ◽  
Author(s):  
Eduardo Vallejo Esquerra ◽  
David R. Herndon ◽  
Francisco Alpirez Mendoza ◽  
Juan Mosqueda ◽  
Guy H. Palmer
Keyword(s):  
High Throughput Sequencing ◽  
Anaplasma Marginale ◽  
Host Population ◽  
Content Type ◽  
Tropical Regions ◽  
Disease Epidemiology ◽  
Infectious Disease Epidemiology ◽  
Perfect Sequence ◽  
Significant Difference ◽  
High Prevalence

ABSTRACTStrain superinfection occurs when a second pathogen strain infects a host already infected with a primary strain. The selective pressures that drive strain divergence, which underlies superinfection, and allow penetration of a new strain into a host population are critical knowledge gaps relevant to shifts in infectious disease epidemiology. In regions of endemicity with a high prevalence of infection, broad population immunity develops againstAnaplasma marginale, a highly antigenically variant rickettsial pathogen, and creates strong selective pressure for emergence of and superinfection with strains that differ in their Msp2 variant repertoires. The strains may emerge either bymsp2locus duplication and allelic divergence on an existing genomic background or by introduction of a strain with a differentmsp2allelic repertoire on a distinct genomic background. To answer this question, we developed a multilocus typing assay based on high-throughput sequencing of non-msp2target loci to distinguish among strains with different genomic backgrounds. The technical error level was statistically defined based on the percentage of perfect sequence matches of clones of each target locus and validated using experimental single strains and strain pairs. Testing ofA. marginale-positive samples from tropical regions whereA. marginaleinfection is endemic identified individual infections that contained unique alleles for all five targeted loci. The data revealed a highly significant difference in the number of strains per animal in the tropical regions compared to infections in temperate regions and strongly supported the hypothesis that transmission of genomically distinctA. marginalestrains predominates in high-prevalence areas of endemicity.

Estimating Trend in Occupancy for the Southern Sierra Fisher Martes pennanti Population

2013 ◽  
Vol 4 (1) ◽  
pp. 3-19 ◽  
Author(s):  
William J. Zielinski ◽  
James A. Baldwin ◽  
Richard L. Truex ◽  
Jody M. Tucker ◽  
Patricia A. Flebbe
Keyword(s):  
Sierra Nevada ◽  
Habitat Degradation ◽  
Monitoring Program ◽  
National Forest Inventory ◽  
Small Population ◽  
Probability Of Detection ◽  
Martes Pennanti ◽  
Entire Study ◽  
Significant Difference ◽  
The One

Abstract Carnivores are important elements of biodiversity, not only because of their role in transferring energy and nutrients, but also because they influence the structure of the communities where they occur. The fisher Martes pennanti is a mammalian carnivore that is associated with late-successional mixed forests in the Sierra Nevada in California, and is vulnerable to the effects of forest management. As a candidate for endangered species status, it is important to monitor its population to determine whether actions to conserve it are successful. We implemented a monitoring program to estimate change in occupancy of fishers across a 12,240-km2 area in the southern Sierra Nevada. Sample units were about 4 km apart, consisting of six enclosed, baited track-plate stations, and aligned with the national Forest Inventory and Analysis grid. We report here the results of 8 y (2002–2009) of sampling of a core set of 223 sample units. We model the combined effects of probability of detection and occupancy to estimate occupancy, persistence rates, and trend in occupancy. In combined models, we evaluated four forms of detection probability (1-group and 2-group both constant and varying by year) and nine forms of probability of occupancy (differing primarily by how occupancy and persistence vary among years). The best-fitting model assumed constant probability of occupancy, constant persistence, and two detection groups (AIC weight  =  0.707). This fit the data best for the entire study area as well as two of the three distinct geographic zones therein. The one zone with a trend parameter found no significant difference from zero for that parameter. This suggests that, over the 8-y period, that there was no trend or statistically significant variations in occupancy. The overall probability of occupancy, adjusted to account for uncertain detection, was 0.367 (SE  =  0.033) and estimates were lowest in the southeastern zone (0.261) and highest in the southwestern zone (0.583). Constant and positive persistence values suggested that sample units rarely changed status from occupied to unoccupied or vice versa. The small population of fishers in the southern Sierra (probably <250 individuals) does not appear to be decreasing. However, given the habitat degradation that has occurred in forests of the region, we favor continued monitoring to determine whether fisher occupancy increases as land managers implement measures to restore conditions favorable to fishers.

scholarly journals A comparative analysis of neck muscle tension in a harvester operator compared with chainsaw and horse skidding operator and with normal human activities

2013 ◽  
Vol 59 (No. 8) ◽  
pp. 301-305
Author(s):  
J. Macků ◽  
J. Dvořák
Keyword(s):  
Experimental Data ◽  
Body Temperature ◽  
Human Activities ◽  
Muscle Tension ◽  
Field Measurements ◽  
Neck Muscle ◽  
Breathing Rate ◽  
Significant Difference ◽  
Normal Human ◽  
Muscle Groups

The goal of the experiment was to assess the physical stress experienced by an operator during the use of harvester equipment. Experimental data was obtained from field measurements with a Biofeedback 2000<sup>x-pert</sup> (BFB) unit, which allows recording of selected physiological parameters on the operator, especially an electromyogram of target muscle groups, body temperature, breathing rate and pulse. Experimental data was interpreted by comparing it with values measured during normal human activities. Measurements were done during logging using a harvester, a chainsaw, while skidding with a horse, while running, and while walking normally. The results of the experiment showed that the electromyograph (EMG) of the investigated muscle groups exhibited values 164% higher during running than during the cut-to-length (CTL) production, up to 77% higher while walking, up to 28% higher during logging with a chainsaw, and even up to 230% higher values while skidding with a horse. Body temperature and pulse measurements did not show a significant difference in values measured during CTL production and during other activities. &nbsp; &nbsp;

Comparative Evaluation of Veriflow®Listeria Species to USDA Culture-Based Method for the Detection of Listeria spp. in Food and Environmental Samples

2017 ◽  
Vol 100 (5) ◽  
pp. 1434-1444 ◽  
Author(s):  
Adam C Joelsson ◽  
Shawn P Terkhorn ◽  
Ashley S Brown ◽  
Amrita Puri ◽  
Benjamin J Pascal ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Ceramic Tile ◽  
Pcr Amplification ◽  
Reference Method ◽  
Probability Of Detection ◽  
Complex Data ◽  
Listeria Species ◽  
Environmental Surfaces ◽  
Study Results ◽  
Significant Difference

Abstract Veriflow®Listeria species (Veriflow LS) is a molecular-based assay for the presumptive detection of Listeria spp. from environmental surfaces (stainless steel, sealed concrete, plastic, and ceramic tile) and ready-to-eat (RTE) food matrixes (hot dogs and deli meat). The assay utilizes a PCRdetection method coupled with a rapid, visual, flow-based assay that develops in 3 min post-PCR amplification and requires only a 24 h enrichment for maximum sensitivity. The Veriflow LS system eliminates the need for sample purification, gel electrophoresis, or fluorophore-based detection of target amplification and does not require complex data analysis. This Performance Tested MethodSM validation study demonstrated the ability of the Veriflow LS assayto detect low levels of artificially inoculated Listeria spp. in six distinct environmental and food matrixes. In each unpaired reference comparison study, probability of detection analysis indicated that there was no significant difference between the Veriflow LS method and the U.S. Department of Agriculture Food Safety and Inspection Service Microbiology Laboratory Guide Chapter 8.08 reference method. Fifty-one strains of various Listeria spp. were detected in the inclusivity study, and 35 nonspecific organisms went undetected in the exclusivity study. The study results show that the Veriflow LS is a sensitive, selective, and robust assay for the presumptive detection of Listeria spp. sampled from environmental surfaces (stainless steel, sealed concrete, plastic, and ceramic tile) and RTE food matrixes (hot dogs and delimeat).

scholarly journals Hypocalcemia is associated with disease severity in patients with dengue

2014 ◽  
Vol 8 (09) ◽  
pp. 1205-1209 ◽  
Author(s):  
Godwin R Constantine ◽  
Senaka Rajapakse ◽  
Priyanga Ranasinghe ◽  
Balasundaram Parththipan ◽  
Ananda Wijewickrama ◽  
...  
Keyword(s):  
Tertiary Care ◽  
Hemorrhagic Fever ◽  
Prognostic Indicator ◽  
Cross Sectional Study ◽  
World Health ◽  
Free Calcium ◽  
Cross Sectional ◽  
Tropical Regions ◽  
Probable Case ◽  
Significant Difference

Introduction: Dengue hemorrhagic fever (DHF) is a major cause of morbidity and mortality in tropical regions. Serum free calcium (Ca2+) is known to be important in cardiac and circulatory function. We evaluated association between serum Ca2+ level and severity of dengue. Methodology:A cross-sectional study was carried out at a tertiary care private hospital in Sri Lanka. A probable case of dengue was diagnosed and classified according to World Health Organization criteria and confirmed by either IgM antibody, PCR, or NS1 antigen detection. Socio-demographic details were collected using an interviewer-administered questionnaire. Results: The sample size was 135. The mean age was 26.1 years, and the majority were males (n = 80, 59.3%). DHF was diagnosed in 71 patients (52.6%). Mean serum Ca2+ level of the study population was 1.05 mmol/L (range 0.77–1.24). Mean serum Ca2+ was significantly higher in patients with dengue fever (DF) (1.09 mmol/L) than in those with DHF (1.02 mmol/L) (p < 0.05). A significant difference was observed between mean serum calcium levels of DHF I and DHF II. Prevalence of hypocalcemia in DHF and DF patients was 86.9% (n = 60) and 29.7% (n = 11), respectively (p < 0.05). Conclusions: Serum Ca2+ levels significantly correlated with dengue severity. Serum Ca2+ levels were significantly lower and hypocalcemia was more prevalent in patients with DHF than in patients with DF. Further studies are required to determine whether hypocalcemia can be utilized as a prognostic indicator and to evaluate effectiveness of calcium therapy in prevention of dengue complications.

Comparative Evaluation of Veriflow® Salmonella Species to USDA and FDA Culture-Based Methods for the Detection of Salmonella spp. in Food and Environmental Samples

2017 ◽  
Vol 100 (5) ◽  
pp. 1445-1457
Author(s):  
Amrita Puri ◽  
Adam C Joelsson ◽  
Shawn P Terkhorn ◽  
Ashley S Brown ◽  
Zara E Gaudioso ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Ceramic Tile ◽  
Ground Beef ◽  
Probability Of Detection ◽  
Salmonella Spp ◽  
Raw Meat ◽  
Environmental Surfaces ◽  
Study Results ◽  
Significant Difference ◽  
The U.S

Abstract Veriflow®Salmonella species (Veriflow SS) is a molecular-based assay for the presumptive detection of Salmonella spp. from environmental surfaces (stainless steel, sealed concrete, plastic, and ceramic tile), dairy (2% milk), raw meat (20%fat ground beef), chicken carcasses, and ready-to-eat (RTE) food (hot dogs). The assay utilizes a PCR detection method coupled with a rapid, visual, flow-based assay that develops in 3 min post-PCR amplification and requires only an 18 h enrichment for maximumsensitivity. The Veriflow SS systemeliminates the need for sample purification, gel electrophoresis, or fluorophore-based detection of target amplification and does not require complex data analysis. This Performance Tested MethodSM validation study demonstrated the ability of the Veriflow SS method to detect low levels of artificially inoculated or naturally occurring Salmonella spp. in eight distinct environmental and food matrixes. Ineach reference comparison study, probability of detection analysis indicated that there was no significant difference between the Veriflow SS method and the U.S. Department of Agriculture Food Safety and Inspection Service MicrobiologyLaboratory Guidebook Chapter 4.06 and the U.S. Food and Drug Administration Bacteriological Analytical Manual Chapter 5 reference methods. A total of 104 Salmonella strains were detected in the inclusivity study, and 35 nonspecific organisms went undetected in the exclusivity study. The study results show that the Veriflow SS method is a sensitive, selective, and robust assay for the presumptive detectionof Salmonella spp. sampled from environmental surfaces (stainless steel, sealed concrete, plastic, and ceramic tile), dairy (2% milk), raw meat (20% fat ground beef), chicken carcasses, and RTE food (hot dogs).

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