THE CAUSES OF ABSENTEEISM OF HIGH SCHOOL STUDENTS

The purpose of this study is to find out the causes of high school students’ absenteeism. Survey method was used. The population was comprised of 531 students in the public high schools. The data was collected with "The Scale of Absenteeism Causes" developed by the researchers. Cronbach Alpha was calculated as α=0.936. Findings show the causes of students' absenteeism aren't related to school, students themselves and their parent, however; student absenteeism causes partly from psychological reasons. Male students have more absenteeism than female students in terms of the causes of absenteeism sourced by school, students and psychological. Moreover; 9th, 10th and 11th grade students' absenteeism has bigger values than 12th grade students.  Article visualizations

The value of systems thinking in operations management : a case study

Includes bibliographical references.This thesis demonstrates the differences between the traditional reductionist approach and the systemic approach to problem solving, and is based on a case study in the manufacturing field. It explains how each approach interprets real life problem situations differently, and emphasises the superiority of systemic approach

The Reliability and Reproducibility of Conventional, Digital and CT Created Cephalograms: A Comparative Study

poster abstractObjective: The purpose of this retrospective radiographic study was to determine the reliability and reproducibility of skeletal and dental measurements of lateral cephalograms created from computed tomography (CT) scan compared to the conventional and digital lateral cephalograms. Method: Following reliability studies, CT records of 30 patients were obtained from the archives. The lateral cephalometric radiographs of these patients were initially manually traced. Then the same radiographs were scanned and traced using Dolphin Imaging software Version 11 (Dolphin Imaging, Chatsworth, CA, USA). Totally 16 (10 angular and 6 linear) measurements were performed. Cephalometric measurements performed on conventional, digital and CT created cephalograms were compared statistically using repeated measures analysis of variance. Statistical significance was set at p<0.05 level. Result: The intrarater reliability test for each method showed high values r >.090 except for the mandibular length which had a correlation of 0.82 for the CT created cephalogram. Five measurements (N-A- Pog, N-S, ANS-PNS, Co-ANS and Co-Gn) were found to be significantly different between the CT created and conventional cephalograms and three measurements (SNB, ANB, and /1-MP) were found to be significantly different between the CT created and digital cephalograms. Conclusion: The measurement differences between the conventional, digital and CT created cephalograms are statistically significant, but clinically acceptable

Identification and genetic characterization of Pseudomonas syringae pv. syringae from sweet cherry in Turkey

Pseudomonas syringae pv. syringae (Pss), which causes bacterial canker, is the most polyphagous bacterium in the P. syringae complex due to its broad host range. This pathogen is considered the major bacterial disease in cherry orchards. In this study, several samples were collected from infected sweet cherry trees in different locations of the Marmara region in Turkey between 2016-2018. Sixty-three isolates were identified as Pss by pathogenicity, LOPAT, GATTa, and MALDI-TOF MS tests. Total genomic DNA was extracted to confirm identity, followed by PCR amplification of syrB and cfl genes. Out of 63 isolates, 12 were randomly selected for Repetitive Element Sequence-based PCR (rep-PCR) and Multilocus Sequence Typing (MLST) analysis to gain insight into the relationships of those isolates. The cluster analysis of rep-PCR (ERIC-, REP- and BOX-PCR) could classify the isolates into two distinct clusters. Phylogenetic analysis was carried out to obtain the relation between isolates and the location.The MLST analysis of gyrB, rpoDp, rpoDs, and gltA genes allowed a clear allocation of the isolates into two separate main clusters. The relationship among the isolates were also evaluated by constructing a genealogical median-joining network (MJN). The isolates from six locations produced 11 haplotypes that were illustrated in the MJN. The results of this study proved that location could not be an indicator for showing the genetic diversity of Pss from cherry orchards. As the genetic variability of Pseudomonads has been demonstrated, the current study also showed high diversity among different isolates even within the populations. While more research is recommended, the results of this study contributed to a better understanding of the Pss evolutionary progress and genetic diversity of sweet cherry isolates

First Report of Bacterial Leaf Spot Caused by Xanthomonas arboricola Infecting Saucer Magnolia in Tennessee

[No Abstract Available

First Report of Powdery Mildew on Physocarpus opulifolius Caused by Podosphaera physocarpi in Tennessee

Eastern ninebark (Physocarpus opulifolius [L.] Maxim.) is a popular native perennial plant used in landscapes because of its colorful foliage and spring flower display. Powdery mildew symptoms were observed on container-grown eastern ninebark ‘Mindia’ Coppertina plants in a commercial nursery in DeKalb County, TN, in May 2016. The disease severity was nearly 40%, and the disease incidence was nearly 60% of 1,000 plants. Affected plants displayed witches’ brooms with cream to white colored, thickened shoots with stunted, curly leaves as well as patches of white powdery fungal growth on the surface of young and old leaves, inflorescences, infructescences, and stems. Microscopic observation revealed masses of conidia and mycelium covering symptomatic tissues. Conidiophore foot cells measured 19.2 to 66.7 μm (mean = 38.3 μm) × 5.4 to 15.1 μm (mean = 9.7 μm) (n = 30). Conidia were ovoid and measured 11.4 to 28.5 μm (mean = 20.9 μm) (n = 30) in length and 8.2 to 14.8 μm (mean = 11.7 μm) (n = 30) in width. Conidiophores produced two to six conidia in chains. Fibrosin bodies were observed after treating conidia with a 3% KOH solution. Chasmothecia were numerous, 60.0 to 85.0 μm (mean = 74.2 μm) (n = 30) in size and contained one ascus (60.0 to 82.0 × 52.0 to 69.0 μm; mean = 73.4 × 59.4 μm [n = 30]) with eight ascospores (25.2 to 28.0 × 14.8 to 16.0 μm; mean = 26.5 × 15.5 μm [n = 30]). To confirm pathogen identity, total DNA was extracted directly from plant tissue with the UltraClean Microbial DNA Isolation Kit (MO BIO Laboratories, Carlsbad, CA) following the manufacturer’s instructions. The internal transcribed spacer region of the ribosomal DNA was amplified by polymerase chain reaction (PCR) using primer pair ITS1 and ITS4 (White et al. 1990). The sequence (GenBank accession no. MT605142) of the amplicon had 100% coverage and 100% identity to that of Podosphaera physocarpi (U. Braun) U. Braun (= Podosphaera aphanis var. physocarpi [U. Braun] U. Braun & S. Takam.) (GenBank accession no. MT106654). Pathogenicity was confirmed three times by inoculating leaf surfaces of five eastern ninebark Mindia Coppertina plants by tapping fungal spores from infected eastern ninebark leaves onto the surfaces of healthy leaves. Inoculated plants were maintained in a greenhouse (21 to 23°C) using a drip irrigation system until symptoms developed. Five noninoculated control plants were maintained in the same greenhouse. After 2 weeks, typical symptoms of powdery mildew developed on the inoculated plants, and microscopic examination revealed the same pathogen morphology as the original isolate. All noninoculated control plants remained disease-free. To our knowledge, this is the first report of powdery mildew caused by P. physocarpi on P. opulifolius in Tennessee. Powdery mildew is known to be a disease problem on eastern ninebark grown in its native range in landscape plantings. Lubell et al. (2011) reported varying levels of powdery mildew resistance among eastern ninebark cultivars. Timely application of fungicides with no phytotoxic effect will be necessary to manage this disease on susceptible eastern ninebark cultivars in affected nurseries

Evaluation of disinfectants to prevent mechanical transmission of viruses and a viroid in greenhouse tomato production

Background In recent years, a number of serious disease outbreaks caused by viruses and viroids on greenhouse tomatoes in North America have resulted in significant economic losses to growers. The objectives of this study were to evaluate the effectiveness of commercial disinfectants against mechanical transmission of these pathogens, and to select disinfectants with broad spectrum reactivity to control general virus and viroid diseases in greenhouse tomato production. Methods A total of 16 disinfectants were evaluated against Pepino mosaic virus (PepMV), Potato spindle tuber viroid (PSTVd), Tomato mosaic virus (ToMV), and Tobacco mosaic virus (TMV). The efficacy of each disinfectant to deactivate the pathogen’s infectivity was evaluated in replicate experiments from at least three independent experiments. Any infectivity that remained in the treated solutions was assessed through bioassays on susceptible tomato plants through mechanical inoculation using inocula that had been exposed with the individual disinfectant for three short time periods (0–10 sec, 30 sec and 60 sec). A positive infection on the inoculated plant was determined through symptom observation and confirmed with enzyme-linked immunosorbent assay (PepMV, ToMV, and TMV) and real-time reverse transcription-PCR (PSTVd). Experimental data were analyzed using Logistic regression and the Bayesian methodology. Results Statistical analyses using logistic regression and the Bayesian methodology indicated that two disinfectants (2% Virkon S and 10% Clorox regular bleach) were the most effective to prevent transmission of PepMV, PSTVd, ToMV, and TMV from mechanical inoculation. Lysol all-purpose cleaner (50%) and nonfat dry milk (20%) were also effective against ToMV and TMV, but with only partial effects for PepMV and PSTVd. Conclusion With the broad spectrum efficacy against three common viruses and a viroid, several disinfectants, including 2% Virkon S, 10% Clorox regular bleach and 20% nonfat dry milk, are recommend to greenhouse facilities for consideration to prevent general virus and viroid infection on tomato plants