Search results for "cluster analysis."
showing 10 items of 805 documents
The gut microbiota of larvae of Rhynchophorus ferrugineus Oliver (Coleoptera: Curculionidae)
2014
Background: The red palm weevil (RPW) Rhynchophorus ferrugineus Olivier (Coleoptera: Curculionidae) is one of the major pests of palms. The larvae bore into the palm trunk and feed on the palm tender tissues and sap, leading the host tree to death. The gut microbiota of insects plays a remarkable role in the host life and understanding the relationship dynamics between insects and their microbiota may improve the biological control of insect pests. The purpose of this study was to analyse the diversity of the gut microbiota of field-caught RPW larvae sampled in Sicily (Italy). Results: The 16S rRNA gene-based Temporal Thermal Gradient Gel Electrophoresis (TTGE) of the gut microbiota of RPW …
A multilocus sequence analysis scheme for characterization of Flavobacterium columnare isolates
2015
Background Columnaris disease caused by Flavobacterium columnare is a serious problem in aquaculture, annually causing large economic losses around the world. Despite considerable research, the molecular epidemiology of F. columnare remains poorly understood. Methods We investigated the population structure and spatiotemporal changes in the genetic diversity of F. columnare population in Finland by using a multilocus sequence typing (MLST) and analysis (MLSA) based on DNA sequence variation within six housekeeping genes. A total of 83 strains of F. columnare were collected from eight different areas located across the country between 2003 and 2012. Results Partial sequencing of six housekee…
Prevalence and genotypes of Borrelia burgdorferi sensu lato infection in Ixodes ricinus ticks in southern Norway.
2010
From April to October 2007, host-seeking Ixodes ricinus ticks were collected from 4 locations in southern Norway: Farsund, Mandal, Sogne and Tromoy. Two hundred and ten larvae, 1130 nymphs and 449 adults were investigated for infection with Borrelia burgdorferi sensu lato (s.l.) by real-time polymerase chain reaction (PCR) amplification of the 16S rRNA gene. The total percentage of B. burgdorferi s.l. in nymphal and adult ticks was determined to be 31.3% in Farsund, 25.2% in Mandal, 22.3% in Sogne and 22.1% in Tromoy. Larvae were pooled in groups of 10 before analysis, and Borrelia infection was detected in 1 of the 21 larvae pools. B. burgdorferi s.l. were genotyped by melting curve analys…
Global Distribution of Shigella sonnei Clones
2011
To investigate global epidemiology of Shigella sonnei, we performed multilocus variable number tandem repeat analysis of 1,672 isolates obtained since 1943 from 50 countries on 5 continents and the Pacific region. Three major clonal groups were identified; 2 were globally spread. Type 18 and its derivatives have circulated worldwide in recent decades.
Incidence, Diversity, and Molecular Epidemiology of Sapoviruses in Swine across Europe▿
2010
ABSTRACT Porcine sapovirus is an enteric calicivirus in domestic pigs that belongs to the family Caliciviridae . Some porcine sapoviruses are genetically related to human caliciviruses, which has raised public health concerns over animal reservoirs and the potential cross-species transmission of sapoviruses. We report on the incidence, genetic diversity, and molecular epidemiology of sapoviruses detected in domestic pigs in a comprehensive study conducted in six European countries (Denmark, Finland, Hungary, Italy, Slovenia, and Spain) between 2004 and 2007. A total of 1,050 swine fecal samples from 88 pig farms were collected and tested by reverse transcription-PCR for sapoviruses, and pos…
Characterization of Listeria monocytogenes isolates from human listeriosis cases in Italy.
2009
ABSTRACT The objective of this study was to characterize by serotyping, pulsed-field gel electrophoresis (PFGE), and PCR amplification of virulence genes and markers of epidemic clones I, II, and III (ECI, ECII, and ECIII) 54 human isolates from apparently sporadic cases of infection occurring in the Lombardy region and in the province of Florence, Tuscany, Italy, in the years 1996 to 2007. Listeria monocytogenes isolates were provided by the clinical microbiology laboratories of the Lombardy region and the “Careggi” Hospital of Florence, Tuscany, Italy. Serotyping, PFGE after digestion with the AscI and ApaI enzymes, and PCR amplification for the inlA , inlC , and inlJ genes and ECI, ECII,…
Genetic heterogeneity and recombination in human type 2 astroviruses
2012
ABSTRACT Novel lineages of human astrovirus (HAstV) types 2, 2c, and 2d have been identified. Upon sequencing of the 3′ end of the genome, the type 2c and 2d HAstVs were found to be open reading frame 1b (ORF1b)-ORF2 recombinant, with ORF1b being derived from type 3 and type 1 HAstVs, respectively. An ORF2 interlineage recombinant strain, 2c/2b, was also identified.
What makes carbon traders cluster their orders?
2014
Abstract The ability to trade large amounts of assets at low costs could be hindered when the size of the orders is concentrated at specific trade sizes. This paper documents evidence of size clustering behavior in the European Carbon Futures Market and analyzes the circumstances under which it happens. Our findings show that carbon trades are concentrated in sizes of one to five contracts and in multiples of five. We have also demonstrated that more clustered prices have more clustered sizes, suggesting that price and size resolution in the European Carbon Market are complementary and that carbon traders round both the price and the size of their orders. Finally, the analysis of the key de…
The validity of collective climates
1999
The objective of this study is to test the validity of the collective climate concept. It was expected that membership in collective climates was related to membership in the collectivities defined by departmental membership, hierarchical level, shift, job location and organizational tenure. The study sample was composed of 195 employees from a central administration agency. Using a combination of hierarchical and non-hierarchical clustering methods, three different collective climates were obtained. The results showed that only hierarchical level was related to collective climate membership. Based on all the results obtained, the debate on the validity of collective climates is reconsidere…
A study of personality subtypes in treatment seeking obese patients
2014
Previous research has not been able to identify a distinct personality style that refers specifically to obese individuals. The purpose of this investigation was to explore whether different personality-based groups can be identified in obese individuals, as has been shown with eating disorder patients. Data were collected from 149 obese patients (BMI = 37.3, ± 6.4; 83% female) seeking dietary treatment and psychological support for their weight problems. Participants completed the Millon Clinical Multiaxial Inventory III (MCMI-III; Millon, 1997) and a battery of eight measures assessing psychological distress, mood states, eating behaviors, obesity-related quality of life, and interperson…