The parasitism of Schistosoma mansoni (Digenea–Trematoda) in a naturally infected population of water rats, Nectomys squamipes (Rodentia–Sigmodontinae) in Brazil

Parasitology ◽  
2000 ◽  
Vol 120 (6) ◽  
pp. 573-582 ◽  
Author(s):  
P. S. D'ANDREA ◽  
L. S. MAROJA ◽  
R. GENTILE ◽  
R. CERQUEIRA ◽  
A. MALDONADO ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Schistosoma Mansoni ◽  
Water Contamination ◽  
Reproductive Parameters ◽  
Contamination Source ◽  
Schistosome Infection ◽  
Migration Patterns ◽  
Capture Recapture ◽  
And Migration

Schistosomiasis is a health problem in Brazil and the role of rodents in maintaining the schistosome life-cycle requires further clarification. The influence of Schistosoma mansoni on a population of Nectomys squamipes was studied by capture-recapture (1st phase, from June 1991 to November 1995) and removal (2nd phase, from April 1997 to March 1999) studies at Sumidouro, Rio de Janeiro, Brazil. During both phases coproscopic examinations were performed. At the 2nd phase the rodents were perfused and worms were counted. The population dynamics of parasites was studied. During the 1st phase, female reproductive parameters, longevity, recruitment and survivorship rates and migration patterns were studied in relation to schistosome prevalence. Water contamination (source of miracidia), abundance intermediate host and rodent migration were related to prevalence. The N. squamipes population was not obviously influenced by the infection, as shown by the high number of reproductive infected females, high longevity of infected individuals and the absence of a relationship between recruitment or survivorship rates and the intensity of schistosome infection. The data indicate that N. squamipes can increase transmission of S. mansoni in endemic areas and carry it to non-infected areas. Furthermore, this rodent can be used as an indicator of a transmission focus.

Conclusion

2007 ◽  
Author(s):  
Michael B. Miller
Keyword(s):  
Immigration Policy ◽  
Migration Patterns ◽  
The Core ◽  
Mass Migration ◽  
And Migration

This final chapter offers a conclusion to the overall findings of the journal. It summarises the core factors of mass migration: migration patterns and networks; the role of governments and immigration policy; the importance of steamship emigration agents; the business of migration; and the shifting role of ports and port infrastructures. It concludes by suggesting that maritime and migration historians can further their studies by expanding and exploring one another’s territories.

scholarly journals Eph receptors and zonation in the rat adrenal cortex

2008 ◽  
Vol 198 (1) ◽  
pp. 185-191 ◽  
Author(s):  
Caroline H Brennan ◽  
Alexandra Chittka ◽  
Stewart Barker ◽  
Gavin P Vinson
Keyword(s):  
Adrenal Cortex ◽  
Enzyme Inhibitor ◽  
Zona Glomerulosa ◽  
Eph Receptors ◽  
Migration Patterns ◽  
Eph Receptor ◽  
Low Sodium Diet ◽  
Low Sodium ◽  
And Migration

Although the zonation of the adrenal cortex has a clear functional role, the mechanisms that maintain it remain largely conjectural. The concept that an outer proliferative layer gives rise to cells that migrate inwards, adopting sequentially the zona glomerulosa, fasciculata and reticularis phenotypes, has yet to be explained mechanistically. In other tissues, Eph receptor (EphR)/ephrin signalling provides a mechanism for cellular orientation and migration patterns. Real-time PCR and other methods were used to determine the possible role of Eph/ephrin systems in the rat adrenal. mRNA coding for several members of the EphR family was detected, but out of these, EphA2 provided the closest parallel to zonal organisation. In situ hybridisation showed that EphA2 mRNA and EphA protein were predominantly located in the zona glomerulosa. Its transcription closely reflected expected changes in the glomerulosa phenotype, thus it was increased after a low-sodium diet, but decreased by pretreatment with the angiotensin-converting enzyme inhibitor, captopril. It was also decreased by ACTH treatment, but unaffected by betamethasone. mRNA coding for ephrin A1, the major ligand for the EphA receptors, was also detected in the rat adrenal, though changes evoked by the various pretreatments did not clearly reflect the expected changes in zonal function. Because the maintenance of cellular zonation requires clear positional signals within the adrenal cortex, these data support a role for Eph forward and reverse signalling in the maintenance of adrenocortical zonation.

scholarly journals Spatiotemporal Analysis of Men Who Have Sex With Men in Mainland China: Social App Capture-Recapture Method

10.2196/14800 ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. e14800
Author(s):  
Maogui Hu ◽  
Chengdong Xu ◽  
Jinfeng Wang
Keyword(s):  
Social Networking ◽  
Mainland China ◽  
Spatiotemporal Analysis ◽  
Yangtze River Delta ◽  
Middle Level ◽  
Migration Patterns ◽  
Adult Men ◽  
Capture Recapture ◽  
Sex With Men ◽  
And Migration

Background In China, the cases of newly diagnosed HIV/AIDS in men who have sex with men (MSM) have increased more than tenfold since 2006. However, the MSM population size, geographical distribution, and migration patterns are largely unknown. Objective Our aim is to estimate the number, spatial distribution, and migration of MSM populations in mainland China using big data from social networking. Methods We collected 85 days of data on online users of a social networking MSM app in mainland China. Daily online MSM users and their migration across the country were investigated during a holiday period and a nonholiday period. Using the capture-mark-recapture model, we designed an experiment consisting of two independent samples to estimate the total provincial MSM population. Results The estimate of MSM in mainland China was 8,288,536 (95% CI 8,274,931-8,302,141), accounting for 1.732% (95% CI 1.729%-1.734%) of adult men aged 18 to 64 years. The average daily number of MSM social networking online across mainland China was 1,198,682 during the nonholiday period. The five provinces (including municipalities) with the highest average number of daily online MSM numbers were Guangdong (n=141,712), Jiangsu (n=90,710), Zhejiang (n=72,212), Shandong (n=68,065), and Beijing (n=66,057). The proportion of daily online MSM among adult men in different cities varied from 0.04% to 0.96%, with a mean of 0.20% (SD 0.14%). Three migrating centers—Guangdong, Beijing, and the Yangtze River Delta (Shanghai-Zhejiang-Jiangsu)—accounted for 57.23% of MSM migrants in the county. Conclusions The percentage of MSM among adult men in mainland China is at the middle level compared with other Asia and Pacific countries. However, the number of MSM is very large, and the distribution is uneven. Both MSM distribution and migration are highly affected by socioeconomic status.

scholarly journals Spatiotemporal Analysis of Men Who Have Sex With Men in Mainland China: Social App Capture-Recapture Method (Preprint)

2019 ◽  
Author(s):  
Maogui Hu ◽  
Chengdong Xu ◽  
Jinfeng Wang
Keyword(s):  
Social Networking ◽  
Mainland China ◽  
Spatiotemporal Analysis ◽  
Yangtze River Delta ◽  
Middle Level ◽  
Migration Patterns ◽  
Adult Men ◽  
Capture Recapture ◽  
Sex With Men ◽  
And Migration

BACKGROUND In China, the cases of newly diagnosed HIV/AIDS in men who have sex with men (MSM) have increased more than tenfold since 2006. However, the MSM population size, geographical distribution, and migration patterns are largely unknown. OBJECTIVE Our aim is to estimate the number, spatial distribution, and migration of MSM populations in mainland China using big data from social networking. METHODS We collected 85 days of data on online users of a social networking MSM app in mainland China. Daily online MSM users and their migration across the country were investigated during a holiday period and a nonholiday period. Using the capture-mark-recapture model, we designed an experiment consisting of two independent samples to estimate the total provincial MSM population. RESULTS The estimate of MSM in mainland China was 8,288,536 (95% CI 8,274,931-8,302,141), accounting for 1.732% (95% CI 1.729%-1.734%) of adult men aged 18 to 64 years. The average daily number of MSM social networking online across mainland China was 1,198,682 during the nonholiday period. The five provinces (including municipalities) with the highest average number of daily online MSM numbers were Guangdong (n=141,712), Jiangsu (n=90,710), Zhejiang (n=72,212), Shandong (n=68,065), and Beijing (n=66,057). The proportion of daily online MSM among adult men in different cities varied from 0.04% to 0.96%, with a mean of 0.20% (SD 0.14%). Three migrating centers—Guangdong, Beijing, and the Yangtze River Delta (Shanghai-Zhejiang-Jiangsu)—accounted for 57.23% of MSM migrants in the county. CONCLUSIONS The percentage of MSM among adult men in mainland China is at the middle level compared with other Asia and Pacific countries. However, the number of MSM is very large, and the distribution is uneven. Both MSM distribution and migration are highly affected by socioeconomic status.

scholarly journals Evidence of the role of free-living birds as disseminators of Salmonella spp.

2020 ◽  
Vol 87 ◽  
Author(s):  
Antonio Jackson Forte Beleza ◽  
William Cardoso Maciel ◽  
Elisângela de Souza Lopes ◽  
Átilla Holanda de Albuquerque ◽  
Arianne Silva Carreira ◽  
...  
Keyword(s):  
North America ◽  
Domestic Animals ◽  
Wild Birds ◽  
Salmonella Spp ◽  
Free Living ◽  
Migration Patterns ◽  
Environment Exposure ◽  
Geographic Regions ◽  
And Migration

ABSTRACT This study aimed to review aspects of Salmonella spp. in free-living birds and their potential as disseminators for domestic animals, man, and the environment. Isolation of Salmonella spp. have been reported in several species of wild birds from Passeridae and Fringillidae, among other avian families, captured in countries of North America and Europe, where Salmonella ser. Typhimurium is the most frequently reported serotype. The presence of pathogens, including Salmonella, may be influenced by several factors, such as diet, environment, exposure to antibiotics, infection by pathogenic organisms and migration patterns. Researches with wild birds that live in urbanized environment are important, considering that birds may participate in the transmission of zoonotic pathogens, which are more prevalent in cities due to the human activity. Based on the information collected, this article concludes that wild birds are still important disseminators of pathogens in several geographic regions and may affect man, domestic animals, and other birds.

Credit constraints and Rural Migration: Evidence from Six Villages in Uttar Pradesh

2018 ◽  
Vol 15 (3) ◽  
pp. 389-398
Author(s):  
Ruchi Singh
Keyword(s):  
Credit Constraints ◽  
Uttar Pradesh ◽  
Binary Logistic Regression ◽  
Binary Logistic Regression Model ◽  
Male Migration ◽  
Rural Economies ◽  
And Migration ◽  
The Relationship ◽  
The Empirical Analysis

Rural economies in developing countries are often characterized by credit constraints. Although few attempts have been made to understand the trends and patterns of male out-migration from Uttar Pradesh (UP), there is dearth of literature on the linkage between credit accessibility and male migration in rural Uttar Pradesh. The present study tries to fill this gap. The objective of this study is to assess the role of credit accessibility in determining rural male migration. A primary survey of 370 households was conducted in six villages of Jaunpur district in Uttar Pradesh. Simple statistical tools and a binary logistic regression model were used for analyzing the data. The result of the empirical analysis shows that various sources of credit and accessibility to them play a very important role in male migration in rural Uttar Pradesh. The study also found that the relationship between credit constraints and migration varies across various social groups in UP.

REFLECTION COEFFICIENT OF AN ELECTROMAGNETIC WAVE IN CONDUCTIVE MEDIA

2018 ◽  
pp. 100-106
Author(s):  
M. S. Sudakova ◽  
M. L. Vladov ◽  
M. R. Sadurtdinov
Keyword(s):  
Reflection Coefficient ◽  
Ground Penetrating Radar ◽  
Electromagnetic Waves ◽  
Water Contamination ◽  
Survey Design ◽  
Direct And Inverse Problems ◽  
The Difference ◽  
Ground Penetrating ◽  
Ideal Dielectric

Within the ground penetrating radar bandwidth the medium is considered to be an ideal dielectric, which is not always true. Electromagnetic waves reflection coefficient conductivity dependence showed a significant role of the difference in conductivity in reflection strength. It was confirmed by physical modeling. Conductivity of geological media should be taken into account when solving direct and inverse problems, survey design planning, etc. Ground penetrating radar can be used to solve the problem of mapping of halocline or determine water contamination.

Role of microenvironment on proliferation and migration of an SDHB silenced murine Pheochromocytoma cell line

2017 ◽  
Author(s):  
Serena Martinelli ◽  
Vanessa D'Antongiovanni ◽  
Susan Richter ◽  
Letizia Canu ◽  
Tonino Ercolino ◽  
...  
Keyword(s):  
Cell Line ◽  
Pheochromocytoma Cell ◽  
And Migration ◽  
Proliferation And Migration

Glioblastoma invasion and NMDA receptors: A novel prospect

2019 ◽  
Vol 106 (3) ◽  
pp. 250-260 ◽  
Author(s):  
DN Nandakumar ◽  
P Ramaswamy ◽  
C Prasad ◽  
D Srinivas ◽  
K Goswami
Keyword(s):  
Glutamate Receptors ◽  
Cell Lines ◽  
Intracellular Signaling ◽  
Transcript Level ◽  
Glioblastoma Cells ◽  
Invasion And Migration ◽  
Matrigel Invasion ◽  
Nmdar Activation ◽  
And Migration

Purpose Glioblastoma cells create glutamate-rich tumor microenvironment, which initiates activation of ion channels and modulates downstream intracellular signaling. N-methyl-D-aspartate receptors (NMDARs; a type of glutamate receptors) have a high affinity for glutamate. The role of NMDAR activation on invasion of glioblastoma cells and the crosstalk with α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) is yet to be explored. Main methods LN18, U251MG, and patient-derived glioblastoma cells were stimulated with NMDA to activate NMDAR glutamate receptors. The role of NMDAR activation on invasion and migration and its crosstalk with AMPAR were evaluated. Invasion and migration of glioblastoma cells were investigated by in vitro trans-well Matrigel invasion and trans-well migration assays, respectively. Expression of NMDARs and AMPARs at transcript level was evaluated by quantitative real-time polymerase chain reaction. Results We determined that NMDA stimulation leads to enhanced invasion in LN18, U251MG, and patient-derived glioblastoma cells, whereas inhibition of NMDAR using MK-801, a non-competitive antagonist of the NMDAR, significantly decreased the invasive capacity. Concordant with these findings, migration was significantly augmented by NMDAR in both cell lines. Furthermore, NMDA stimulation upregulated the expression of GluN2 and GluA1 subunits at the transcript level. Conclusions This study demonstrated the previously unexplored role of NMDAR in invasion of glioblastoma cells. Furthermore, the expression of the GluN2 subunit of NMDAR and the differential overexpression of the GluA1 subunit of AMPAR in both cell lines provide a plausible rationale of crosstalk between these calcium-permeable subunits in the glutamate-rich microenvironment of glioblastoma.

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