Spatial clustering and associations of two savannah tsetse species, Glossina morsitans submorsitans and Glossina pallidipes (Diptera: Glossinidae), for guiding interventions in an adaptive cattle health management framework

2010 ◽  
Vol 100 (6) ◽  
pp. 661-670 ◽  
Author(s):  
A. Sciarretta ◽  
Getachew Tikubet ◽  
J. Baumgärtner ◽  
Melaku Girma ◽  
P. Trematerra
Keyword(s):  
Health Management ◽  
Spatial Clustering ◽  
Hot Spot ◽  
Temporal Distribution ◽  
Glossina Pallidipes ◽  
Monitoring And Control ◽  
Glossina Morsitans ◽  
Glossina Morsitans Submorsitans ◽  
The North ◽  
Short Rainy Season

AbstractThe paper deals with tsetse (family Glossinidae) control and aims at improving the methodology for precision targeting interventions in an adaptive pest management system. The spatio-temporal distribution of Glossina morsitans submorsitans Newstead, and Glossina pallidipes Austen, at Ethiopia's Keto pilot site, is analyzed with the spatial analysis by distance indices (SADIE) methodology that focus on clustering and spatial associations between species and between sexes. Both species displayed an aggregated distribution characterised by two main patches in the south and an extended gap in the north. Spatial patterns were positively correlated and stable in most cases, with the exception of the early dry season and the short rainy season when there were differences between the species and sexes. For precision targeting interventions, the presented methods here are more effective than the previously used geostatistical analyses for identifying and delimiting hot spots on maps, measuring shapes and sizes of patches, and discarding areas with low tsetse density. Because of the improved knowledge on hot spot occurrences, the methods allow a better delimitation of the territory for control operations and a more precise computation of the number of the relatively expensive traps used for monitoring and control purposes.

scholarly journals Changes in the spatial pattern of net earnings: Evidence from Serbia

2015 ◽  
Vol 65 (3) ◽  
pp. 351-365 ◽  
Author(s):  
Uglješa Stankov ◽  
Vanja Dragićević
Keyword(s):  
Spatial Autocorrelation ◽  
Spatial Clustering ◽  
Hot Spot ◽  
Spatial Segregation ◽  
Cold Spot ◽  
Spatial Autocorrelation Analysis ◽  
Autocorrelation Analysis ◽  
The North ◽  
Spatial Changes ◽  
Global And Local

Spatial autocorrelation analysis is an important method that can reveal the structure and patterns of economic spatial variables. It can be used to identify not only global spatial patterns in the country, but also characteristic locations at micro levels. In this research, we used spatial autocorrelation methodologies, including Global Moran’s I and Local Getis—Ord Gi statistics to identify the intensity of the spatial clustering of municipalities in Serbia by the level of average monthly net earnings from 2001 to 2010. We identified and mapped local clusters (hot and cold spots) by the level of average monthly net earnings for the same period. The results show that overall spatial segregation between municipalities with high and low average monthly net earnings was predominantly increasing during the investigated period. Local statistics illustrated that overall spatial segregation followed a broad north—south divide, with a concentration of municipalities with high net earnings in the north of Serbia, and low net earnings in the south. Closer inspection showed that at the beginning of the study period, there were three statistically significant hot spots in the north. As time passed, only one highly clustered hot spot remained — the Belgrade region. One cold spot retained a relatively stable position in the country’s southeast. This research shows that spatial changes of net earnings can be successfully studied with respect to statistically significant global and local spatial associations in the variables using spatial autocorrelation analysis.

Rate of linear advance by Glossina morsitans submorsitans newst. (Diptera, Glossinidae) on a trade cattle route in south-western Nigeria

1976 ◽  
Vol 66 (2) ◽  
pp. 365-372 ◽  
Author(s):  
K. Riordan
Keyword(s):  
Tsetse Fly ◽  
Dispersal Rate ◽  
The South ◽  
Glossina Morsitans ◽  
Short Term ◽  
Indigenous Cattle ◽  
Glossina Morsitans Submorsitans ◽  
The North ◽  
Major Route ◽  
River Niger

AbstractIndigenous cattle are trekked, along well defined routes, from the north of Nigeria to markets in the south of the country. A major route crosses the River Niger at Jebba and proceeds south through Ilorin, Ogbomosho and Oyo towns. In 1912 the tsetse fly Glossina morsitans submorsitans Newst. was absent from this route south of Jebba. The species appeared mid-way between Jebba and Ilorin in about 1935, reached Ilorin by about 1950 and Oyo by, or before, 1967. The rate of southwards advance, if linear, was about 5·4 km per year or 104 m per week.The Jebba-Oyo infestation may have originated, not as a southwards extension of a fly belt north of the River Niger at Jebba (now termed Belt 24), as generally believed, but by immigration of flies from Eastern Ilorin Province, known to be heavily infested as early as 1912. Several cattle routes from that area converged north of Ilorin before the present route became predominant.G. m. submorsitans was eradicated from the route south of Ogbomosho by insecticide spraying in January 1970. The rate of re-invasion of this section was measured for the next three years and found to be about 5·13 km per year or 99 m per week, proceeding faster during dry than during wet seasons.The calculated rates of advance, both long and short term, were about half the figure (180 m per week) proposed by other workers as the dispersal rate of individual flies, which is believed to determine rates of advance. The relative slowness of the present advance was probably related to the equability of the climate, in which seasonal increases and decreases in fly population were slight.

scholarly journals Bovine trypanosomosis and its fly vectors in three selected settlement areas of Hawa-Gelan district, western Ethiopia

2014 ◽  
Vol 81 (1) ◽  
Author(s):  
Kumela Lelisa ◽  
Shihun Shimeles ◽  
Jemere Bekele ◽  
Desie Sheferaw
Keyword(s):  
Community Involvement ◽  
Glossina Pallidipes ◽  
Cross Sectional Study ◽  
Sectional Study ◽  
Glossina Morsitans ◽  
Cross Sectional ◽  
Glossina Morsitans Submorsitans ◽  
Bovine Trypanosomosis ◽  
Western Ethiopia ◽  
Settlement Areas

A cross-sectional study aimed at investigating the species diversity of fly vectors and estimating the prevalence of bovine trypanosomosis was carried out from October 2009 to May 2010 in selected settlement areas of the Hawa-Gelan district in the western Wollega zone of Ethiopia. Standard methods of sampling and identification were employed for both entomological and parasitological examination. Three species of the genus Glossina (Glossina pallidipes, Glossina morsitans submorsitans and Glossina fuscipes) and two genera of biting flies (Stomoxys and Tabanus) were caught and identified. The overall apparent density of Glossina species caught was 10.5 flies per trap per day, with a higher proportion of female flies (57.2%). Out of a total 389 cattle examined, 42 (10.8%; 95% CI: 7.89% – 14.3%) were found infected with trypanosomes. Three trypanosome species were detected in the study area, namely Trypanosoma congolense (54.8%), Trypanosoma brucei (23.8%) and Trypanosoma vivax (21.4%). The prevalence of trypanosomosis was found to be significantly (p < 0.05) higher in cattle with poor body condition. There was an association between mean packed cell volume (PCV) and the occurrence of parasitaemia (χ2 = 49.5, p < 0.05). About 95.2% of cattle that were positive for trypanosomes had a PCV less than the lower limit for cattle. Considering the current result, bovine trypanosomosis seems to be a serious constraint for agricultural activities in the settlement areas of the Hawa-Gelan district and seems to be associated with the presence of Glossina species. Therefore, application of control methods through community involvement to reduce the Glossina species infestation level is likely to increase animal productivity.

Assessment of Turbulent Processes in Lake Kinneret by the Two-Dimensional Reservoir Water Quality Model “Better”

1993 ◽  
Vol 27 (7-8) ◽  
pp. 381-385 ◽  
Author(s):  
Y. Oziransky ◽  
B. Shteinman
Keyword(s):  
Water Body ◽  
River Mouth ◽  
Temporal Distribution ◽  
Lake Kinneret ◽  
Toxic Substances ◽  
Two Dimensional ◽  
Quality Model ◽  
Reservoir Water ◽  
The North ◽  
Longitudinal Gradients

Data of high spatial and temporal resolution, and a special sampling program are essential for successful application of mathematical models designed to reproduce observed seasonal patterns of temperature, dissolved oxygen, nutrients, pH, and algal biomass for both vertical and longitudinal gradients in a water body. Lake Kinneret suspended solids are of great potential value for estimating transport, exposure to water body elements, and fate of many toxic substances. Therefore the distribution of admixtures in two longitudinal and five vertical segmentation schemes were examined with the two-dimensional water body quality box model “BETTER” (Bender et al, 1990). The transects were taken in the north-western part of Lake Kinneret close to the Jordan River mouth and the National Water Carrier (NWC) head pumping station. The outflow volumes were given according to regular sampling of natural speed of water outflow from different lake layers under calm conditions. Temporal distribution of mixing concentrations as well as turbulent diffusion horizontal coefficients due to the spatial distribution of turbulent scale were obtained during the model's run with the December 1991 data.

scholarly journals Spatial clustering of drug-resistant tuberculosis in Hunan province, China: an ecological study

BMJ Open ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. e043685
Author(s):  
Kefyalew Addis Alene ◽  
Zuhui Xu ◽  
Liqiong Bai ◽  
Hengzhong Yi ◽  
Yunhong Tan ◽  
...  
Keyword(s):  
Treatment Outcomes ◽  
Cumulative Incidence ◽  
Ecological Study ◽  
Spatial Clustering ◽  
Hunan Province ◽  
Drug Resistant ◽  
Drug Resistant Tuberculosis ◽  
The North ◽  
Resistant Tuberculosis ◽  
Over Time

ObjectiveThis study aimed to investigate the spatial distribution of drug-resistant tuberculosis (DR-TB) in Hunan province, China.MethodsAn ecological study was conducted using DR-TB data collected from the Tuberculosis Control Institute of Hunan Province between 2012 and 2018. Spatial clustering of DR-TB was explored using the Getis-Ord statistic. A Poisson regression model was fitted with a conditional autoregressive prior structure, and with posterior parameters estimated using a Bayesian Markov chain Monte Carlo simulation, to quantify associations with possible risk factors and identify clusters of high DR-TB risk.ResultsA total of 2649 DR-TB patients were reported to Hunan TB Control Institute between 2012 and 2018. The majority of the patients were male (74.8%, n=1983) and had a history of TB treatment (88.53%, n=2345). The proportion of extensively DR-TB among all DR-TB was 3.3% (95% CI 2.7% to 4.1%), which increased from 2.8% in 2012 to 4.4% in 2018. Of 1287 DR-TB patients with registered treatment outcomes, 434 (33.8%) were cured, 198 (15.3%) completed treatment, 92 (7.1%) died, 108 (8.3%) had treatment failure and 455 (35.3%) were lost to follow-up. Half (50.9%, n=655) had poor treatment outcomes. The annual cumulative incidence rate of notified DR-TB increased over time from 0.25 per 100 000 people in 2012 to 0.83 per 100 000 people in 2018. Substantial spatial heterogeneity was observed, and hotspots were detected in counties located in the North and East parts of Hunan province. The cumulative incidence of notified DR-TB was significantly associated with urban communities.ConclusionThe annual incidence of notified DR-TB increased over time in Hunan province. Spatial clustering of DR-TB was detected and significantly associated with urbanisation. This finding suggests that targeting interventions to the highest risk areas and population groups would be effective in reducing the burden and ongoing transmission of DR-TB.

scholarly journals Spatial–Temporal Distribution Variation of Ground-Level Ozone in China’s Pearl River Delta Metropolitan Region

2021 ◽  
Vol 18 (3) ◽  
pp. 872
Author(s):  
An Zhang ◽  
Jinhuang Lin ◽  
Wenhui Chen ◽  
Mingshui Lin ◽  
Chengcheng Lei
Keyword(s):  
Ozone Concentration ◽  
Pearl River Delta ◽  
Temporal Distribution ◽  
Ground Level ◽  
Metropolitan Region ◽  
Pearl River ◽  
Ozone Pollution ◽  
Ground Level Ozone ◽  
Ozone Concentrations ◽  
The North

Long-term exposure to ozone pollution will cause severe threats to residents’ physical and mental health. Ground-level ozone is the most severe air pollutant in China’s Pearl River Delta Metropolitan Region (PRD). It is of great significance to accurately reveal the spatial–temporal distribution characteristics of ozone pollution exposure patterns. We used the daily maximum 8-h ozone concentration data from PRD’s 55 air quality monitoring stations in 2015 as input data. We used six models of STK and ordinary kriging (OK) for the simulation of ozone concentration. Then we chose a better ozone pollution prediction model to reveal the ozone exposure characteristics of the PRD in 2015. The results show that the Bilonick model (BM) model had the highest simulation precision for ozone in the six models for spatial–temporal kriging (STK) interpolation, and the STK model’s simulation prediction results are significantly better than the OK model. The annual average ozone concentrations in the PRD during 2015 showed a high spatial variation in the north and east and low in the south and west. Ozone concentrations were relatively high in summer and autumn and low in winter and spring. The center of gravity of ozone concentrations tended to migrate to the north and west before moving to the south and then finally migrating to the east. The ozone’s spatial autocorrelation was significant and showed a significant positive correlation, mainly showing high-high clustering and low-low clustering. The type of clustering undergoes temporal migration and conversion over the four seasons, with spatial autocorrelation during winter the most significant.

The 25 October, 2018 Zakynthos (Greece) earthquake: seismic activity at the transition between a transform fault and a subduction zone.

2020 ◽  
Author(s):  
P Papadimitriou ◽  
V Kapetanidis ◽  
A Karakonstantis ◽  
I Spingos ◽  
K Pavlou ◽  
...  
Keyword(s):  
Spatial Clustering ◽  
Accretionary Prism ◽  
Velocity Model ◽  
Strike Slip ◽  
Double Difference ◽  
Strain Partitioning ◽  
Transform Fault ◽  
Fault Plane Solutions ◽  
The North ◽  
Waveform Modelling

Summary The properties of the Mw = 6.7 earthquake that took place on 25 October 2018, 22:54:51 UTC, ∼50 km SW of the Zakynthos Island, Greece, are thoroughly examined. The main rupture occurred on a dextral strike-slip, low-angle, east-dipping fault at a depth of 12 km, as determined by teleseismic waveform modelling. Over 4000 aftershocks were manually analysed for a period of 158 days. The events were initially located with an optimal 1D velocity model and then relocated with the double-difference method to reveal details of their spatial distribution. The latter spreads in an area spanning 80 km NNW-SSE and ∼55 km WSW-ENE. Certain parts of the aftershock zone present strong spatial clustering, mainly to the north, close to Zakynthos Island, and at the southernmost edge of the sequence. Focal mechanisms were determined for 61 significant aftershocks using regional waveform modelling. The results revealed characteristics similar to the mainshock, with few aftershocks exhibiting strike-slip faulting at steeper dip angles, possibly related to splay faults on the accretionary prism. The slip vectors that correspond to the east-dipping planes are compatible with the long-term plate convergence and with the direction of coseismic displacement on the Zakynthos Island. Fault-plane solutions in the broader study area were inverted for the determination of the regional stress-field. The results revealed a nearly horizontal, SW-NE to E-W-trending S1 and a more variable S3 axis, favouring transpressional tectonics. Spatial clusters at the northern and southern ends of the aftershock zone coincide with the SW extension of sub-vertical along-dip faults of the segmented subducting slab. The mainshock occurred in an area where strike-slip tectonics, related to the Cephalonia Transform Fault and the NW Peloponnese region, gradually converts into reverse faulting at the western edge of the Hellenic subduction. Plausible scenarios for the 2018 Zakynthos earthquake sequence include a rupture on the subduction interface, provided the slab is tilted eastwards in that area, or the reactivation of an older east-dipping thrust as a low-angle strike-slip fault that contributes to strain partitioning.

scholarly journals Estimation of harp seal (Pagophilus groenlandicus) pup production in the North Atlantic completed: results from surveys in the Greenland Sea in 2002

2006 ◽  
Vol 63 (1) ◽  
pp. 95-104 ◽  
Author(s):  
Tore Haug ◽  
Garry B. Stenson ◽  
Peter J. Corkeron ◽  
Kjell T. Nilssen
Keyword(s):  
North Atlantic ◽  
Barents Sea ◽  
Temporal Distribution ◽  
Harp Seal ◽  
Greenland Sea ◽  
The North ◽  
Pagophilus Groenlandicus ◽  
Pack Ice ◽  
Photographic Survey ◽  
Strip Transect

Abstract From 14 March to 6 April 2002 aerial surveys were carried out in the Greenland Sea pack ice (referred to as the “West Ice”), to assess the pup production of the Greenland Sea population of harp seals, Pagophilus groenlandicus. One fixed-wing twin-engined aircraft was used for reconnaissance flights and photographic strip transect surveys of the whelping patches once they had been located and identified. A helicopter assisted in the reconnaissance flights, and was used subsequently to fly visual strip transect surveys over the whelping patches. The helicopter was also used to collect data for estimating the distribution of births over time. Three harp seal breeding patches (A, B, and C) were located and surveyed either visually or photographically. Results from the staging flights suggest that the majority of harp seal females in the Greenland Sea whelped between 16 and 21 March. The calculated temporal distribution of births were used to correct the estimates obtained for Patch B. No correction was considered necessary for Patch A. No staging was performed in Patch C; the estimate obtained for this patch may, therefore, be slightly negatively biased. The total estimate of pup production, including the visual survey of Patch A, both visual and photographic surveys of Patch B, and photographic survey of Patch C, was 98 500 (s.e. = 16 800), giving a coefficient of variation of 17.9% for the survey. Adding the obtained Greenland Sea pup production estimate to recent estimates obtained using similar methods in the Northwest Atlantic (in 1999) and in the Barents Sea/White Sea (in 2002), it appears that the entire North Atlantic harp seal pup production, as determined at the turn of the century, is at least 1.4 million animals per year.

Temporal distribution and population structure of two congeneric species ofCucullanus(Nematoda: Cucullanidae) inOrthopristis ruberin Venezuela

2008 ◽  
Vol 82 (1) ◽  
pp. 69-76 ◽  
Author(s):  
A.K. Bashirullah ◽  
M.T. Diaz
Keyword(s):  
Temporal Distribution ◽  
Caribbean Sea ◽  
Congeneric Species ◽  
Mean Intensity ◽  
Qualitative And Quantitative ◽  
The North ◽  
Significant Difference ◽  
The Caribbean ◽  
Over Exploitation ◽  
Fish Hosts

AbstractThe qualitative and quantitative parameters of temporal distribution ofCucullanus tripapillatusandCucullanus chrysophrydesin the intestine ofOrthopristis ruberin the Caribbean Sea on the north of Margarita Island, Venezuela were analysed. A total of 540 fish were collected at random from the catch of commercial trawlers during 1982–83 and 1992–93. Both species ofCucullanuswere found throughout the year; prevalence and mean intensity ofC. tripapillatuswere higher than that ofC. chrysophrydes. A significant difference was found in infection between the two years of sampling. Female worms were more abundant than male in both years. Both species exhibited pronounced prevalence and maturity in September and March of each year, indicating seasonality. The patterns of occurrence of the two species ofCucullanusinO. ruberdid not change in the 10-year interval but the host size and number of parasites declined, which may be due to over-exploitation of definitive fish hosts.

Aircraft Applications of Insecticides in East Africa. VI.—Applications of a coarse Aerosol containning DDT to control the Tsetse Flies, Glossina morsitans Westw., Glossina swynnertoni Aust. and Glossina pallidipes Aust.

1954 ◽  
Vol 45 (3) ◽  
pp. 585-603 ◽  
Author(s):  
K. S. Hocking ◽  
D. Yeo ◽  
D. G. Anstey
Keyword(s):  
Random Effects ◽  
Glossina Pallidipes ◽  
Tsetse Flies ◽  
Glossina Morsitans ◽  
Median Diameter ◽  
Coarse Aerosol ◽  
Savannah Woodland ◽  
Mass Median ◽  
Glossina Swynnertoni ◽  
Mass Median Diameter

An experiment is described where applications of a coarse aerosol were made to savannah woodland containing the tsetse flies, Glossina moritans Westw., G. swynnertoni Aust. and G. pallidipes Aust.Seven applications were made, each at a nominal dosage of 0·25 lb. of technical DDT per acre and 0·25 gallons of solution per acre. The applications in any particular part of the treaed woodland covered an interval of 90 days, or rather more than two pupal periods.The coarse aerosol was produced by emitting the insecticidal solution under pressure through fine nozzles fitted to a boom. It had a mass median diameter of approximately 60 microns, and droplet dismeters varied from a few microns to approximately 200 microns.The population of G. pallidipes was so drastically reduced that it has subsequently dies out. The reduction of G. morsitans was approximately 95 per cent. The differences between the reductions are attributed mainly to differences between the ease with which the three species can be killed. It is pointed out that this is not necessarily equivalent to differences in susceptibility.Comparisons are made with previous experiments, and the different results of the various experiments are difficult to explian satisfactory. The increased cover in savannah areas during the leafy period may have reduced the effectiveness of the applications, and the total periods covered by the various series of applications were probably also important. Random effects, leading to ineffective treatments, may also be important.Costs are discussed.

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