scholarly journals Spatial and temporal aggregation of Oryzaephilus surinamensis from Peninsular Malaysia

2021 ◽  
Vol 58 (04) ◽  
pp. 1123-1130
Author(s):  
Syed Ahmad Syarifah Zulaikha
Keyword(s):  
Central Zone ◽  
Temporal Distribution ◽  
Peninsular Malaysia ◽  
Management Control ◽  
P Value ◽  
Distribution Analysis ◽  
Pest Species ◽  
Stored Products ◽  
Population Abundance ◽  
Oryzaephilus Surinamensis

The saw-toothed grain beetle, Oryzaephilus surinamensis (Linnaeus) is a secondary pest of rice grains and other stored products. Lack of information on the population abundance, spatial, and temporal distribution of O. surinamensis rendered the management control strategy of this pest species less effective. The objective of this study was to investigate the abundance, spatial and temporal pattern of O. surinamensis populations from nine rice warehouses in three zones of Peninsular Malaysia (i.e., the northern, central and southern zones) for three continuous months. The results showed that the abundance of O. surinamensis populations varied significantly (p<0.05, p= 0.00) between zones, with the highest abundance for this species (69%) recorded from the Klang District, in the central zone, followed by Pasir Gudang (27%) in the southern zone, and Seberang Prai (4%) in the northern zone. The patterns of population abundance also showed significant differences between months, p<0.05 (p-value= 0.00-0.011) between all the warehouses. The factors that could be associated with the highest abundance of the pest were attributed to poor sanitation at the warehouses and inconsistency in the fumigation regime. For the spatial distribution analysis, SADIEShell_122 and Surfer8 software were applied. The distribution patterns of O. surinamensis populations varied significantly in all the warehouses, being significantly aggregated at p<0.05 (p=0.0385-0.0513) and Ia>1.0 (1.212-1.579), whilst being non-significantly and randomly distributed at p>0.05 (p=0.1154-0.91032) and Ia>1.0 (0.852- 0.929). The significance of the aggregation might be due to the rapidly changing volume of the rice stock caused by the active and rapid turnover of the storage inventory. The results obtained were very valuable and informative in managing O. surinamensis infestation of stored rice by incorporating the spatial and temporal information of the pest populations in the management strategy for improving the rice and other stored products.

scholarly journals Haplotype Analysis and Phylogeny of Oryzaephilus surinamensis Populations from Four Regions in Peninsular Malaysia

2021 ◽  
Vol 44 (3) ◽  
Author(s):  
Syed Ahmad Syarifah-Zulaikha ◽  
Madihah Halim ◽  
Ameyra Zuki Aman ◽  
Salmah Yaakop
Keyword(s):  
Haplotype Diversity ◽  
Haplotype Network ◽  
Peninsular Malaysia ◽  
Small Scale ◽  
Pest Species ◽  
Oryzaephilus Surinamensis ◽  
Storage Losses ◽  
Similar Haplotype ◽  
Coi Sequences ◽  
Haplotype 1

The sawtoothed grain beetle, Oryzaephilus surinamensis, is a secondary pest that damages rice products and other stored grains. Analysis based on the cytochrome oxidase subunit I (COI) sequences data, the number of haplotypes (Hap) (n), haplotype diversity (Hd), haplotype network, genetic distance, and phylogeny between O. surinamensis populations from four regions (small-scale), viz. the northern area (Seberang Perai), middle area (Klang), southern area (Pasir Gudang), and east coast (Kuantan) of Peninsular Malaysia, as model sampling locations, were obtained. A total of five haplotypes were detected in all the test populations, two shared (Haplotype 1 and Haplotype 3) and three unique haplotypes (Haplotype 2, Haplotype 4, and Haplotype 5) with haplotype diversity value, Hd = 0.6789 were recorded. Furthermore, the neighbour-joining (NJ), maximum parsimony (MP), and Bayesian inference (BI) trees showed a mixture of individuals from all regions in Peninsular Malaysia (Haplotype 1 to Haplotype 4), except Haplotype 5, which was grouped with foreign populations that inherited similar haplotype with those of the European samples. This study assumed a mixture of populations presumably due to human activities and related explicitly to the exportation and importation of rice products across regions. This information is vital for strategising the control management of this pest species to reduce rice storage losses.

scholarly journals Hypoglycemia Prevention Practice and Associated Factors Among Patients with Diabetes Mellitus Following at Public Hospitals of Central Zone, Tigray, Ethiopia, 2018

2019 ◽  
Author(s):  
Gebrewahd Bezabh Gebremichael ◽  
Teklewoini Mariye Zemichael
Keyword(s):  
Diabetes Mellitus ◽  
Associated Factors ◽  
Central Zone ◽  
Public Hospitals ◽  
P Value ◽  
Diabetic Patients ◽  
Binary Logistic Regression Model ◽  
Cross Sectional ◽  
Patients With Diabetes ◽  
At Home

Abstract Background Hypoglycemia is an acute medical situation that occurs when blood sugar falls below the recommended level. Even though, hypoglycemia prevention practice in the management of diabetes mellitus is one cornerstone in controlling the effect of hypoglycemia, hypoglycemia prevention practice among patients with diabetes mellitus is insufficiently studied. Moreover, the existed scarce literature in Ethiopia revealed hypoglycemia prevention practice is inadequate. Thus, this study tried to assess hypoglycemia prevention practices and associated factors among diabetic patients. Methods Hospital-based, cross-sectional study design was employed from April one to March one 2018 in Central Zone of Tigray Regional state of Ethiopia. A total of 272 diabetes mellitus patients were selected by systematic random sampling method from study area. The collected data was checked for its completeness and then entered into Epi data version 3.1 then cleaned and analyzed using SPSS version 23. Binary logistic regression model (AOR, 95% CI and p-value < 0.05) was used to determine the predictors of hypoglycemia prevention practice. Results the mean age of respondents was 52.19 years and about 100 (63.2%) had good hypoglycemia prevention practice. Knowledge regarding hypoglycemia [AOR = 10.34; 95% CI [5.41, 19.89]], having a glucometer at home [AOR=3. 02; 95% CI [1.12, 8.12]], attitude regarding diabetes mellitus [AOR = 2.36 CI [1.26, 4.39]], being governmental employee [AOR=5. 19, 95% CI [1.63, 16.58]] and being divorced [AOR = 0.13, 95% CI [0.32, 0.53]] were found significantly associated with good hypoglycemia prevention practice. Conclusion Around two third of the study participants were found to have good hypoglycemia prevention practice. Good knowledge and favorable attitude toward diabetes mellitus, having glucometer at home, being governmental employee and divorced were found to be the predictors of good hypoglycemia prevention practice.

The influence of fluids in the unusually high-rate seismicity in the Ometepec segment of the Mexican subduction zone

2021 ◽  
Author(s):  
D Legrand ◽  
A Iglesias ◽  
S K Singh ◽  
V Cruz-Atienza ◽  
C Yoon ◽  
...  
Keyword(s):  
Subduction Zone ◽  
Temporal Distribution ◽  
Aftershock Sequence ◽  
High Rate ◽  
Earth Tides ◽  
P Value ◽  
Plate Interface ◽  
Flow Measurements ◽  
Slow Slip Events ◽  
Mexican Subduction Zone

Summary The rate of earthquakes with magnitudes Mw ≤ 7.5 in the Ometepec segment of the Mexican subduction zone is relatively high as compared to the neighboring regions of Oaxaca and Guerrero. Although the reason is not well understood, it has been reported that these earthquakes give rise to a large number of aftershocks. Our study of the aftershock sequence of the 2012 Mw7.4 Ometepec thrust earthquake suggests that it is most likely due to two dominant factors: (1) The presence of an anomalously high quantity of over-pressured fluids near the plate interface, and (2) the roughness of the plate interface. More than 5,400 aftershocks were manually detected during the first ten days following the 2012 earthquake. Locations were obtained for 2,419 events (with duration magnitudes Md ≥ 1.5). This is clearly an unusually high number of aftershocks for an earthquake of this magnitude. Furthermore, we generated a more complete catalog, using an unsupervised fingerprint technique, to detect more smaller events (15,593 within one month following the mainshock). For this catalog, a high b-value of 1.50 ± 0.10 suggests the presence of fluid release during the aftershock sequence. A low p-value (0.37 ± 0.12) of the Omori law reveals a slow decaying aftershock sequence. The temporal-distribution of aftershocks shows peaks of activity with two dominant periods of 12h and 24h that correlate with the Earth tides. To explain these observations, we suggest that the 2012 aftershock sequence is associated with the presence of over-pressured fluids and/or a heterogeneous and irregular plate interface related to the subduction of the neighboring seamounts. High fluid content has independently been inferred by magneto-telluric surveys and deduced from heat flow measurements in the region. The presence of fluids in the region has also been proposed to explain the occurrence of slow slip events, low frequency earthquakes, and tectonic tremors.

scholarly journals Hypothesis Testing in High-Throughput Screening for Drug Discovery

2012 ◽  
Vol 17 (4) ◽  
pp. 519-529 ◽  
Author(s):  
Michael Prummer
Keyword(s):  
Drug Discovery ◽  
High Throughput ◽  
High Throughput Screening ◽  
Large Scale ◽  
Single Point ◽  
Error Rates ◽  
P Value ◽  
Distribution Analysis ◽  
Use Of Resources ◽  
Compound Screening

Following the success of small-molecule high-throughput screening (HTS) in drug discovery, other large-scale screening techniques are currently revolutionizing the biological sciences. Powerful new statistical tools have been developed to analyze the vast amounts of data in DNA chip studies, but have not yet found their way into compound screening. In HTS, characterization of single-point hit lists is often done only in retrospect after the results of confirmation experiments are available. However, for prioritization, for optimal use of resources, for quality control, and for comparison of screens it would be extremely valuable to predict the rates of false positives and false negatives directly from the primary screening results. Making full use of the available information about compounds and controls contained in HTS results and replicated pilot runs, the Z score and from it the p value can be estimated for each measurement. Based on this consideration, we have applied the concept of p-value distribution analysis (PVDA), which was originally developed for gene expression studies, to HTS data. PVDA allowed prediction of all relevant error rates as well as the rate of true inactives, and excellent agreement with confirmation experiments was found.

Theoretical basis for the use of pathogens as biological control agents of pest species

Parasitology ◽  
1982 ◽  
Vol 84 (4) ◽  
pp. 3-33 ◽  
Author(s):  
R. M. Anderson
Keyword(s):  
Population Growth ◽  
Mathematical Models ◽  
Horizontal Transmission ◽  
Host Density ◽  
Host Population ◽  
Pest Species ◽  
Population Abundance ◽  
Pest Population ◽  
Insect Pathogen ◽  
Cyclic Changes

SUMMARYThe population dynamics of insect–pathogen interactions are examined with the aid of simple mathematical models. Three concepts of central importance to the interpretation of population behaviour are discussed, namely the ability of the pathogen to persist within its host population, the ability to regulate and depress host population abundance, and the ability to induce non-seasonal cyclic changes in host density. The selection of pathogen species or strains to depress pest population growth is discussed and the optimal characteristics are shown to be intermediate pathogencity combined with an ability to reduce infected host reproduction, high transmission efficiency, including elements of vertical as well as horizontal transmission stages. When the pathogen plays a significant role in the regulation of host population growth, it is argued that many insect–pathogen interactions will exhibit non-seasonal oscilations in host and pathogen abundance. Mathematical models are used to explore the patterns of population behaviour that result from the continual introduction of a pathogen into a target pest population. It is shown that there exists a critical introdution rate, above which the eradication of the pest is theoretically possible. Significant reductions in pest population abundance will not occur until the introduction rate approaches this critical value, whereupon the oscillatory behaviour of the interaction between host and pathogen population will be suppressed.A general dicussion is given of the problems arising from the combined use of chemical agents and pathogens for the control of pest species, and the evolutionary pressures acting on host and pathogen populations.

scholarly journals Spatial distribution of inselbergs in Igbajo district of Western Nigeria

2021 ◽  
Vol 13 (2) ◽  
Author(s):  
Matthew Afolabi ◽  
Olayinka Ogunkoya
Keyword(s):  
Spatial Distribution ◽  
Point Pattern Analysis ◽  
Point Pattern ◽  
P Value ◽  
Distribution Analysis ◽  
Nearest Neighbour ◽  
Test Statistic ◽  
Drainage Pattern ◽  
River Drainage ◽  
Significant Difference

Inselbergs’ spatial distribution is the primary focus of this study carried out in Igbajo District of Western Nigeria. Additionally, a common hypothesis that spatial distribution of inselbergs is informed by the differing modes of evolution of the landforms was also examined. Inselbergs are defined as points on the topographic sheet and satellite terrain elevation data and are thereafter subjected to point pattern analysis. Two point pattern analyses: Poisson Probability Distribution (PPD) and Nearest Neighbour Analysis (NNA) are employed to determine the pattern of inselberg distribution over space. Additional analysis focused on the relationship between regional river drainage and inselbergs’ spatial distribution. Findings from the study confirmed that inselberg form a clustered distribution. The PPD results suggest that the observed distribution of inselbergs has a statistically significant difference from the expected pattern generated by the random process (c2 test statistic = 49.82 >  =12.59 (α= 0.05) and 16.81 (α= 0.01). Similarly, the NNA with a R < 1 (Nearest Neighbour Ratio, R = 0.92) and p-value = -2.52, also indicated a clustered distribution. Analysis of river drainage pattern similarly revealed a cluster of high rising landforms situated in the centre of the regional watershed. It is concluded that inselberg distribution in the study area is clustered although the observed pattern does not necessarily validate or invalidate the alternative evolutionary theories.

scholarly journals A Genomic Snapshot of the SARS-CoV-2 Pandemic in the Balearic Islands

2022 ◽  
Vol 12 ◽  
Author(s):  
Carla López-Causapé ◽  
Pablo A. Fraile-Ribot ◽  
Santiago Jiménez-Serrano ◽  
Gabriel Cabot ◽  
Ester del Barrio-Tofiño ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Temporal Distribution ◽  
Balearic Islands ◽  
Distribution Analysis ◽  
Key Factors ◽  
Consensus Sequences ◽  
Genomic Epidemiology ◽  
Size Population ◽  
Lineage Distribution ◽  
Selection Of

Objective: To analyze the SARS-CoV-2 genomic epidemiology in the Balearic Islands, a unique setting in which the course of the pandemic has been influenced by a complex interplay between insularity, severe social restrictions and tourism travels.Methods: Since the onset of the pandemic, more than 2,700 SARS-CoV-2 positive respiratory samples have been randomly selected and sequenced in the Balearic Islands. Genetic diversity of circulating variants was assessed by lineage assignment of consensus whole genome sequences with PANGOLIN and investigation of additional spike mutations.Results: Consensus sequences were assigned to 46 different PANGO lineages and 75% of genomes were classified within a VOC, VUI, or VUM variant according to the WHO definitions. Highest genetic diversity was documented in the island of Majorca (42 different lineages detected). Globally, lineages B.1.1.7 and B.1.617.2/AY.X were identified as the 2 major lineages circulating in the Balearic Islands during the pandemic, distantly followed by lineages B.1.177/B.1.177.X. However, in Ibiza/Formentera lineage distribution was slightly different and lineage B.1.221 was the third most prevalent. Temporal distribution analysis showed that B.1 and B.1.5 lineages dominated the first epidemic wave, lineage B.1.177 dominated the second and third, and lineage B.1.617.2 the fourth. Of note, lineage B.1.1.7 became the most prevalent circulating lineage during first half of 2021; however, it was not associated with an increased in COVID-19 cases likely due to severe social restrictions and limited travels. Additional spike mutations were rarely documented with the exception of mutation S:Q613H which has been detected in several genomes (n = 25) since July 2021.Conclusion: Virus evolution, mainly driven by the acquisition and selection of spike substitutions conferring biological advantages, social restrictions, and size population are apparently key factors for explaining the epidemic patterns registered in the Balearic Islands.

scholarly journals A Spatio-temporal distribution analysis of vesicular stomatitis outbreak in Ecuador, 2018

Bionatura ◽  
2021 ◽  
Vol 6 (2) ◽  
Author(s):  
María Teresa Salinas ◽  
Euclides José De La Torre ◽  
Paola Katerine Moreno ◽  
Andrés Alejandro Vaca ◽  
Rubén Alexander Maldonado
Keyword(s):  
Spatial Dynamics ◽  
Disease Outbreaks ◽  
Temporal Distribution ◽  
Viral Disease ◽  
Space Time ◽  
Scan Statistics ◽  
Economic Losses ◽  
Distribution Analysis ◽  
Tissue Samples ◽  
Vesicular Stomatitis

Vesicular stomatitis (VS) is a viral disease primarily affecting cattle, swine, and equine causing economic losses. It is of particular interest because its outward signs are similar to those of foot-and-mouth disease. Outbreaks of VS occurred in several herds in Ecuador in 2018, affecting principally bovines. In this sense, the present study was conducted to characterize the temporal and spatial dynamics of Vesicular stomatitis occurrence between January and December 2018. During the study period, 583 animals with symptoms of VS were reported. In this way, tissue samples were collected, VS was diagnosed, and outbreaks were defined as herds with a confirmed positive test for the disease. Outbreaks were georeferenced, and Space-time clusters were used to determine zones where the number of reported outbreaks was more significant than expected. A space-time permutation scan statistic (STPSS) was used to identify hot spots of space-time interaction within patterns of the cases reported. Standard Monte Carlo Critical Value was used to test for the cluster's significance. A total of 399 outbreaks were presented in 18 provinces. Spatial scan statistics allowed the detection of four significant space-time clusters of VS outbreaks. The highest incidence was reported around week 35 and week 44, which were observed outbreaks increase in the country's north region. In this sense, clusters coincided with the areas with the highest incidence of outbreaks. Besides, maps showed places where the disease is not shared. The information showed in the present study may contribute to prevents VS spread into regions of Ecuador that is only sporadically affected by the disease. Monitoring in affected zones may lead to quick responses to possible outbreaks issuing alerts when there is a greater than typical risk of spreading the disease

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