Enhanced degradation of metalaxyl in agricultural soils of São Paulo State, Brazil

This work investigated the effect of repeated applications on enhanced degradation of metalaxyl in two different agricultural soils used for cultivation of orange and lemon from Casa Branca and Itapetininga districts of São Paulo State, Brazil. Soil samples were collected from areas repeatedly treated with commercial ridomil 50GR for six successive years, and from other areas never exposed to this fungicide. At the laboratory, soil samples received a 14C-metalaxyl solution and its degradation was studied through radiometric techniques to measure biomineralization and recovery of extractable- and soil-bound products. Enhanced degradation was verified only in one soil, although partial degradation and mineralization of the fungicide were detected in both soils. The different rates and patterns of metalaxyl degradation in the soils were probably due to their different physical, chemical, and biological characteristics.

Radarsat backscattering from an agricultural scene

Orbital remote sensing in the microwave electromagnetic region has been presented as an important tool for agriculture monitoring. The satellite systems in operation have almost all-weather capability and high spatial resolution, which are features appropriated for agriculture. However, for full exploration of these data, an understanding of the relationships between the characteristics of each system and agricultural targets is necessary. This paper describes the behavior of backscattering coefficient (sigma°) derived from calibrated data of Radarsat images from an agricultural area. It is shown that in a dispersion diagram of sigma° there are three main regions in which most of the fields can be classified. The first one is characterized by low backscattering values, with pastures and bare soils; the second one has intermediate backscattering coefficients and comprises well grown crops mainly; and a third one, with high backscattering coefficients, in which there are fields with strong structures causing a kind of double bounce effect. The results of this research indicate that the use of Radarsat images is optimized when a multitemporal analysis is done making the best use of the agricultural calendar and of the dynamics of different cultures.

Impacts of climate change on the agricultural zoning of climate risk for cotton cultivation in Brazil

The objective of this work was to evaluate the effect of the temperature increase forecasted by the Intergovernmental Panel on Climate Change (IPCC) on agricultural zoning of cotton production in Brazil. The Northeastern region showed the highest decrease in the low-risk area for cotton cultivation due to the projected temperature increase. This area in the Brazilian Northeast may decrease from 83 million ha in 2010 to approximately 71 million ha in 2040, which means 15% reduction in 30 years. Southeastern and Center-Western regions had small decrease in areas suitable for cotton production until 2040, while the Northern region showed no reduction in these areas. Temperature increase will not benefit cotton cultivation in Brazil because dimension of low-risk areas for economic cotton production may decrease.

Prediction of soil shear strength in agricultural and natural environments of the Brazilian Cerrado

The objective of this work was to develop uni- and multivariate models to predict maximum soil shear strength (τmax) under different normal stresses (σn), water contents (U), and soil managements. The study was carried out in a Rhodic Haplustox under Cerrado (control area) and under no-tillage and conventional tillage systems. Undisturbed soil samples were taken in the 0.00-0.05 m layer and subjected to increasing U and σn, in shear strength tests. The uni- and multivariate models - respectively τmax=10(a+bU) and τmax=10(a+bU+cσn) - were significant in all three soil management systems evaluated and they satisfactorily explain the relationship between U, σn, and τmax. The soil under Cerrado has the highest shear strength (τ) estimated with the univariate model, regardless of the soil water content, whereas the soil under conventional tillage shows the highest values with the multivariate model, which were associated to the lowest water contents at the soil consistency limits in this management system.

Síntese de biodiesel: uma proposta contextualizada de experimento para laboratório de química geral

The contextualized understanding of concepts in Chemistry by students from other areas is a challenging task. In this experiment, the synthesis of biodiesel is done by base catalyzed transesterification of refined soy oil with methanol at room temperature and common glassware found in any chemistry laboratory. The proposal permits introducing several concepts, such as that of emulsion, viscosity and catalysis to illustrate an activity based on an actual problem. In this didactic approach, some common problems of biodiesel production, such as soap formation and phase separation, are introduced into the procedure in order to raise questions and motivate the students to participate in the experimental work and stimulate reflections about critical aspects of biodiesel production. This experiment was carried out in the first semester of 2006, in experimental general chemistry taken by physics and agricultural, civil and chemical engineering students of UNICAMP.

A brief introduction to molecular orbital theory of simple polyatomic molecules for undergraduate chemistry students

A simple, four-step method for better introducing undergraduate students to the fundamentals of molecular orbital (MO) theory of the polyatomic molecules H2O, NH3, BH3 and SiH4 using group theory is reported. These molecules serve to illustrate the concept of ligand group orbitals (LGOs) and subsequent construction of MO energy diagrams on the basis of molecular symmetry requirements.

Factors associated with depressive symptoms in a sample of Brazilian medical students

OBJECTIVES: 1 - Verify the prevalence of depressive symptoms in first to fourth-year medical students using the Beck Depression Inventory (BDI). 2 - Establish correlations between target factors and higher or lower BDI scores. 3 - Investigate the relationship between the prevalence of depressive symptoms and the demand for psychological care offered by the Centro Universitário Lusíada. METHOD: Cross-sectional study of 290 first to fourth-year medical students; implementation of the BDI, socio-demographic survey, and evaluation of satisfaction with progress. RESULTS: The study sample was 59% female and 41% male. Mean BDI was 6.3 (SD 5.8). Overall prevalence of depressive symptoms was 23.1%. The following associations were statistically significant (p<0.05): among students for whom the course failed to meet original expectations, who were dissatisfied with the course, or who came from the interior of the State (20.5%, 12.5%, and 24.4% of the total sample, respectively), for 40%, 36.1% and 36.4%, respectively, the BDI was consistent with some degree of depression. CONCLUSION: The study showed that there is higher prevalence of depressive symptoms in medical students than in the general population

Group mentoring for junior medical students: perceptions of mentees and mentors

Entering medical school can be associated with a number of difficulties that can hinder students' performance. Mentoring programs are designed to help students circumvent difficulties and improve their learning and personal development. The current study aimed to evaluate the perceptions of both students and mentors regarding a recently introduced, group-based mentoring program designed to support first-year students. After one year of regular meetings, students and mentors' perceptions of the program were assessed by means of structured questionnaires. Response content categories were identified through multiple readings. Both regular attendees and non-participating students had positive opinions about the program. Mentors were highly satisfied at having participated and acknowledged that the program has been useful not only for assisting students, but also for fostering their own personal and professional development. In conclusion, the group-based mentoring program is feasible and can elicit positive views from both mentors and students. In addition, faculty members' participation as mentors can also be beneficial, since the program appears to contribute to their own personal and professional development

Knowledge of common pediatric cancers among medical students in northeast Brazil

BACKGROUND: In recent decades, early diagnosis of childhood cancer has taken an important place on the international agenda. The authors of this study evaluated a group of medical students in Recife, Brazil, regarding knowledge and practices related to early diagnosis of common childhood cancers. METHODS: Cross-sectional study with a sample of 82 medical students, from a total of 86 eligible subjects. Data were collected using self-completed questionnaires. Subgroups were defined according to knowledge of the theme and students' perceptions of their own skills and interest in learning. RESULTS: 74.4% of the sample demonstrated a minimum level of knowledge. The group without minimum knowledge or self-perceived competence to identify suspected cases (23.3%) was in the worst position to perform early diagnosis. All subjects expressed interest in learning more about this topic. CONCLUSIONS: Despite acceptable levels of knowledge among these medical students, the definition of central aspects of the teaching and learning processes would be useful for training physicians with the skills for diagnosing and treating pediatric cancers

Active teaching-learning methodologies: medical students' views of problem-based learning

The prevailing undergraduate medical training process still favors disconnection and professional distancing from social needs. The Brazilian Ministries of Education and Health, through the National Curriculum Guidelines, the Incentives Program for Changes in the Medical Curriculum (PROMED), and the National Program for Reorientation of Professional Training in Health (PRO-SAÚDE), promoted the stimulus for an effective connection between medical institutions and the Unified National Health System (SUS). In accordance to the new paradigm for medical training, the Centro Universitário Serra dos Órgãos (UNIFESO) established a teaching plan in 2005 using active methodologies, specifically problem-based learning (PBL). Research was conducted through semi-structured interviews with third-year undergraduate students at the UNIFESO Medical School. The results were categorized as proposed by Bardin's thematic analysis, with the purpose of verifying the students' impressions of the new curriculum. Active methodologies proved to be well-accepted by students, who defined them as exciting and inclusive of theory and practice in medical education.

Medical students' knowledge about end-of-life decision-making

The influence of medical students' knowledge concerning end-of-life care, considering ethical theories and clinical practice, remains controversial. We aimed to investigate medical students' knowledge of bioethical concepts related to moral kinds of death (euthanasia, disthanasia, and orthothanasia) and to analyze the influence of their clinical experience on practicing such approaches in a tertiary hospital in the state of São Paulo, Brazil. We interviewed 180 medical students [distributed in Group 1 (G1) - first to third- year students, and Group 2 (G2) - fourth to sixth-year students] to evaluate the influence of the course on "medical ethics" on ethical theories and clinical practice, using a closed questionnaire. The course on "medical ethics" did not distinguish the groups (P=0.704) in relation to bioethical concepts. Neologisms such as "cacothanasia" and "idiothanasia" were incorrectly viewed as bioethical concepts by 28% of the interviewees. Moreover, 45.3% of the sample considered health care professionals incapable of managing terminally ill patients, especially G2 (29%) as compared to G1 (16.5%, P=0.031). The concept of euthanasia was accepted by 41% of sample, as compared to 98.2% for orthothanasia. Among medical students that accepted ways to abbreviate life (22.9%), 30.1% belonged to G1, and only 16.1% to G2 (P=0.049). These medical students were unfamiliar with common bioethical concepts. Moreover, they considered healthcare professionals incapable of managing terminally ill patients. The ethical ideal of the "good death" reflects better acceptance of orthothanasia by medical students, suggesting a tendency to apply it in their future clinical practice.

Mentors, students, and the undergraduate medical course: a virtuous circle

BACKGROUND: Mentoring Programs have been developed in several medical schools, but few studies have investigated the mentors'perspective. PURPOSES: To explore mentors'perceptions regarding their experience. METHODS: Mentors at a medical school were invited to participate in an in-depth interview including questions on satisfaction, difficulties, and perception of changes resulting from the program. RESULTS: Mentors' satisfaction and difficulties are strongly associated with students'involvement in the activity. Mentors believe changes observed in students were more related to life issues; for some mentors, there is no recognition or awareness of the program. However, most of the mentors acknowledged important changes in relation to themselves: as teachers, faculty members, and individuals. CONCLUSION: Attendance is crucial for both the mentoring relationship and strengthening of the program. Students involved in the activity motivate mentors in teaching and curriculum development, thereby creating a virtuous circle and benefiting undergraduate medical education as a whole.

Clinical reasoning of medical students in a public university in Brazil

The aim of this research was to understand the reasoning developed by medical students in a public university in Brazil. This research on education included semi-structured interviews and film recordings of interns discussing 10 clinical cases. A sample of 16 interns analyzed cases presented on a notebook computer with a webcam. They were instructed to verbalize all their thoughts on the procedures they would use. The film recordings and transcripts of the interviews were analyzed. Quantitative data was evaluated using Yates' chi-squared test and speech analysis was used to evaluate the transcripts. The theme worked on in the practice of reasoning was: the student's perceptions of their clinical practice. Of the 160 diagnoses, 57% were done with analytical reasoning and 43% with non-analytical reasoning. The hypothetical deductive method was employed by 31% of the interns and the inductive method was employed by 69%. The diagnostic accuracy was 81% correct for easy cases and 85% correct for difficult cases. We observed two empirical categories: the cognitive universe of the student and the patient's context.

Abnormal eating behaviors among medical students at a university in southern Santa Catarina, Brazil

OBJECTIVES: Disturbances in eating behavior significantly affect young adults. This study aimed to estimate the prevalence of abnormal eating behaviors, according to the Eating Attitudes Test - 26 (EAT-26) in medical students at a university in southern Santa Catarina State, Brazil. METHODS: Self-reported questionnaire, based on the EAT-26 scale, was administered to medical students. Additional questions about age, gender, study period of the course, weight and height were asked. A total of 391 medical students were assessed, amounting to 93.3 percent of the 419 students enrolled. RESULTS: Ten percent of the surveyed subjects had positive EAT-26 scores. This outcome measure was positive associated with females (PR 6.5), body mass index (BMI) ≤ 25 kg/m² (PR 4.5), age ≤ 20 years (PR 1.3) and being student from 1st to 5th semester of the course (PR 1.7). A higher proportion of women gave positive responses to behaviors related to control of food intake or weight loss than men. CONCLUSION: The significant prevalence of behaviors related to eating disorders, predominantly among women, suggests the implementation of preventive measures targeting this population.

Prevalence of Anxiety and Depression among Medical Students

ABSTRACT Background Medical students are a vulnerable population to develop depression and anxiety disorders. Objective To estimate the prevalence and associated factors of anxiety and depression among medical students. Methods A cross-sectional study with a random sample (n = 346) of medical students at a Brazilian university was performed. The Beck Depression Anxiety Inventory was used to measure anxiety and depression levels. Crude and adjusted analyses were performed using Poisson regression. Results The prevalence of anxiety was 35.5% and depression was 32.8%. The prevalence of anxiety and depression was 14% higher and 16% higher among women (p = 0.025 and p = 0.006, respectively). Students whose parents were not physicians reported 23% higher prevalence of anxiety (p = 0.006), and those who had physician parents reported 29% higher prevalence of depression (p = 0.034). Those who always or often felt pushed by their parents showed 22% higher prevalence of anxiety (p =.006) and 19% higher depression (p = 0.016). Students who had concerns over the future had 15% higher prevalence of depression (p = 0.017). Conclusion The prevalence of anxiety and depressive symptoms was higher than the average found in the general population.