Revisão sistemática de pesquisas sobre eficácia coletiva docente / Systematic review on researches about collective teacher efficacy

A eficácia coletiva docente é a percepção compartilhada pelos professores sobre a capacidade do corpodocentede organizar e executar ações necessárias a um efeito positivo no desempenho acadêmico dosalunos. Este artigo tem o objetivo de construir um panorama das pesquisas sobre eficácia coletiva deprofessores, analisando seus principais resultados. Para tanto, foram realizadas buscas de artigospublicados entre 2000 e 201 3, na base de dados Portal de Periódicos Capes. Os resultados indicam que aeficácia coletiva de professores está diretamente relacionada ao desempenho acadêmico dos alunos.Notou-se ainda que outras variáveis podem influenciar as crenças coletivas, tais como a autoeficácia e asituação socioeconômicada escola(AU)

Is colonic electrical activity a similar phenomena to small-bowel electrical activity?

PURPOSE: This study was designed to investigate colonic spike bursts regarding 1) their migration behavior, 2) their pressure correlates, and 3) comparing colonic short spike bursts with spike bursts from migrating myoelectric complex from the small bowel. METHODS: Rectosigmoid electromyography and manometry were recorded simultaneously in seven normal volunteers and electromyography alone in five others during two hours of fasting and for two hours after one 2,100-kJ meal. One patient with an ileostomy was also studied by the same method to record the migrating myoelectric complex from the terminal ileum during fasting. RESULTS: Three kinds of spike bursts were observed in the pelvic colon: rhythmic short spike bursts, migrating long spike bursts, and nonmigrating long spike bursts. The meal significantly increased the number of migrating and nonmigrating long spike bursts (from 25 to 38.7 percent of the recording time; P < 0.01). These bursts of potentials showed a peak 15 minutes after the meal, which may be caused by the gastrocolic reflex. Migrating long spike bursts started anywhere along the rectosigmoid and migrated from there aborad 82 percent of the time and orad or in both directions in 10 or 7 percent of the time, respectively. They originated pressure waves 99 percent of the time. Short spike bursts were more frequent before the meal (15.1 percent before and 9.6 percent after the meal), but the difference was not significant; they neither propagated nor initiated pressure waves detected by the mini-balloon. CONCLUSIONS: Migrating long spike bursts were the only potentials that migrated, sometimes for short distances. Short spike bursts are a different phenomenon from the small-bowel migrating myoelectric complex because they do not migrate; they can occur during the postprandial period and never originated intraluminal pressure waves.

Electromyography and manometry of the pelvic colon--a contribution to the understanding of its function.

OBJECTIVE: To study the adaptation of the rectum to pressure waves in the sigmoid and the motility response to the administration of a bile salt microenema. DESIGN: Electrical and motor activity was studied in 20 men and 20 women during a 2-h fast and for 2 h after a 1000-kcal meal, and also after a bile salt microenema. METHODS: An intraluminal probe with three sets of two electrodes and one miniballoon was used for simultaneous EMG and manometry recording. RESULTS: Four types of spike bursts were observed: (1) migrating long spike bursts that initiated propagating pressure waves on 99% of occasions; (2) non-migrating long spike bursts that did not originate pressure waves; (3) rhythmic short spike bursts that were also not related to pressure waves; and (4) rhythmic long spike bursts that originated rhythmic segmental pressure waves frequently brought up by a migrating long spike burst. The meal significantly increased the duration of activity of the migrating long spike bursts in the sigmoid colon (from 16.8% before the meal to 21.8% after it, P < 0.05) and the motility index, P < 0.05, both of them in two peaks. A rectosigmoidal pressure gradient was shown. The bile salt microenema produced a desire to defecate and increased motility in only half of the cases. CONCLUSION: The rectosigmoidal pressure gradient was due to: (1) higher-amplitude pressure waves in the sigmoid colon than in the other two sites, and (2) propagating relaxation waves in the rectum and in the rectosigmoid junction.

Colonic transit times and the effect of lactulose or lactitol in hospitalized patients.

OBJECTIVE: To investigate whether a small dose (10 g per day) of a laxative (liquid lactulose, crystallized lactulose, or crystallized lactitol) can prevent the slow colonic transit associated with the physical inactivity of hospitalization. DESIGN: Patients were randomly allocated to one of four groups: control, liquid lactulose, crystallized lactulose or crystallized lactitol, and the average of mean colonic transit times in these groups was compared. SETTING: Gastroenterologic Unit, Hospital dos Covoes, Coimbra, Portugal. PATIENTS: Patients with normal bowel movements, admitted to hospital for the investigation of conditions not associated with constipation or diarrhoea, were allocated to one of the four treatment groups and had their mean colonic transit times studied after hospitalization using radiopaque markers and abdominal radiographs. Each study group had 18 patients. During the study, each patient was given a normal diet and no drugs except the relevant laxative. RESULTS: The average of the mean colonic transit times in each of the four groups were: 52.16 h [95% confidence interval (CI) 39.42-64.84] for controls; 22.45 h (95% CI 13.84-31.06) in the liquid lactulose group; 24.05 (95% CI 12.13-35.97) in the crystallized lactulose group; and 35.95 (95% CI 23.82-48.08) in the crystallized lactitol group. The differences were statistically significant for the two lactulose groups. The study of the mean colonic regional transit times showed that these differences related to transit in the right colon. CONCLUSIONS: A small dose of lactulose (either liquid or crystallized) was effective in preventing slow colonic transit and constipation in hospitalized patients without causing unwanted symptoms. The slow transit affected mainly the right colon, and it was in this region that the laxative had effect.