Using mathematical models to describe aerial dispersal and silk ball formation of peanut red spider mite, Tetranychus ogmophallos (Acari: Tetranychidae).

Peanut red spider mite, Tetranychus ogmophallos, exhibits a peculiar dispersal behavior using silk balls, which involves clustering of mites and spinning of webs at the top of plants. Such a dispersal mechanism has not been studied for this species yet. Therefore, this study aimed at using mathematical models to describe aerial dispersal and silk ball formation of peanut red spider mite on peanut plants. The influence of wind speed, generated by a wind tunnel, on the dispersal of mites was studied in two experiments, one with 500 mites per plant and one with 1000 mites per plant, and six wind speeds (5, 10, 15, 20, 25, and 30 km h-1) for each mite density. The proportion of displaced mites and the distance they were blown were measured. Another series of experiments considered the formation of silk balls to assess how fast balls were formed as a function of time and the number of mites present on a peanut plant. Data from the wind tunnel experiments were analyzed by logistic regression and multiple regression to assess the proportion of displaced mites and the distance moved, respectively, as functions of wind speed and the initial density of mites on the donor plant. The distribution of dispersal distances from the donor plant was fitted by a mathematical model proposed by Ricker (J Fish Res Board Can 11:559-623, 1954). The number of mites moving upwards on a plant to be involved in silk ball formation was modeled as a function of time based on the initial number of spider mites and their estimated birth, death and movement rates per capita. Logistic regression was used to analyze the presence of balls as a function of time elapsed since a plant was infested with spider mites. Finally, non-linear regression was applied to link ball size to the total number of mites occupying the ball. The data analyses revealed that wind speed had a significant positive effect on take-off probability and distance moved by individual mites, whereas mite density had little influence. Ricker's model adequately described the distribution of dispersal distances. The models describing silk ball formation also described data very well. Ball size was found to increase almost linearly with the number of mites found in the ball. We expect that the knowledge provided by the present study will help to develop efficient management strategies against T. ogmophallos in peanut crops as dispersal seems to be a key factor in the species' capability to become a serious pest.

Feelings, perceptions, and expectations of patients during the process of oral cancer diagnosis.

PURPOSE: Communication barriers during the process of cancer diagnosis can adversely affect how patients understand their health, and understanding patient's perceptions and expectations can favor adherence to professional recommendations and their prognosis. This study aimed to describe the sociodemographic characteristics, perceptions, expectations, and psychological symptoms of patients during the process of oral cancer diagnosis. METHODS: Patients were assessed at two time points: pre-biopsy (T0) and post-diagnosis (T1). At T0, 49 patients answered a sociodemographic, perceived social support, lifestyle questionnaire and inventories (anxiety-State-Trait Anxiety Inventory (STAI-S/T), depression-Beck Depression Inventory (BDI), risk drinkers-Alcohol Use Disorders Identification Test (AUDIT)). They also were interviewed concerning their perceptions, feelings, and expectations. At T1, the 29 patients diagnosed with oral cancer were reassessed for anxiety (STAI-E) and depression symptoms. An interview investigated the same aspects at T0. RESULTS: Patient mean age was 59 years old (±13.7) and 73.5 % were men. At T0, depression symptoms were more frequent among cancer patients (83.3 %) than those without the disease (p < 0.05), with a prevalence of 36.7 %. Patients presented anxiety (40.8 %) and alcohol abuse behavior (32.6 %). Associations between characteristics and categories at T0 showed that patients with lower income and living with a partner reported negative feelings (p < 0.05) more frequently, together with negative expectations concerning the diagnosis among older patients (p < 0.05) and those with depressive symptoms (p < 0.05). At T1, negative feelings were more frequently reported among patients with anxiety (p < 0.01) and depression symptoms (p < 0.05). CONCLUSION: Professional support and care regarding the psychological aspects and characteristics of patients is required during the diagnosis process in order to promote patient adhesion and favorable prognosis.

Student self-confidence in coping with uncooperative behaviours in paediatric dentistry.

During paediatric dental treatment, non-collaboration and fearful reactions are frequently observed in the child client. The dentistry student must be prepared to cope with these reactions, particularly considering the importance of the relationship between dentists and patients in the promotion of oral health. The present study aimed to assess undergraduate dentistry students' perceptions of their ability to cope with non-collaboration situations in paediatric dentistry. A Likert-style questionnaire was used to analyse students' self-confidence levels, and proposed solutions to 10 problem situations the students would be likely to encounter were recorded. The questionnaire was administered to two undergraduate dentistry student groups from two different Brazilian Public Faculties, comprising 122 respondents. The self-confidence analysis indicated that it varied according to the extent of the child's reaction and the invasiveness of the procedure. Responses to the open-ended questions were categorised by solution proposed, and the analysis indicated that the most frequent responses were categorised as follows: tranquilising, explanation and restriction. Significant differences were found in tranquilising (with higher values for Faculty 2 than 1, and higher values for female students than male students at Faculty 2) and restriction (with higher values for female students compared with male student at both Faculties). The results and discussion focused on the aspects of training dentistry students' social and behavioural management skills.