Cognitive, perceptual and action-oriented representations of falling objects

We interact daily with moving objects. How accurate are our predictions about objects' motions? What sources of information do we use? These questions have received wide attention from a variety of different viewpoints. On one end of the spectrum are the ecological approaches assuming that all the information about the visual environment is present in the optic array, with no need to postulate conscious or unconscious representations. On the other end of the spectrum are the constructivist approaches assuming that a more or less accurate representation of the external world is built in the brain using explicit or implicit knowledge or memory besides sensory inputs. Representations can be related to naive physics or to context cue-heuristics or to the construction of internal copies of environmental invariants. We address the issue of prediction of objects' fall at different levels. Cognitive understanding and perceptual judgment of simple Newtonian dynamics can be surprisingly inaccurate. By contrast, motor interactions with falling objects are often very accurate. We argue that the pragmatic action-oriented behaviour and the perception-oriented behaviour may use different modes of operation and different levels of representation.     

Structure-activity relationships of dengue antiviral polycyclic quinones

The virucidal and antiviral photoactivities of three compounds, hypericin, tetrabromohypericin and gymnochrome B, were evaluated against dengue viruses. All the three products were active, and both the virucidal and antiviral activities were enhanced by light. Gymnochrome B was more potent than hypericin and tetrabromohypericin. The presence of the side chains on the hypericin core of gymnochromes appears to be beneficial for both virucidal and antiviral activities. This enhanced activity is likely to be linked to a complementary mechanism independent of photoactivation.     

Theoretical evaluation of the susceptometric measurement of iron in human liver by four different susceptometers

This paper is an evaluation of liver iron quantification using a simulated magnetic susceptibility measurement in the hepatic region. Susceptometers having homogeneous and non-homogeneous magnetizing fields coupled with axial second-order and planar first-order gradiometric magnetic detectors were considered. The intensity of magnetic flux threading the detector coils was evaluated considering samples with volume and susceptibility equivalent to liver iron, tissue and lung air individually. These volumes were represented by cylindrical and spherical geometries. The main sources of error in quantifying iron overload in susceptometric measurement of hepatic tissue were evaluated for four configurations of the susceptometer.     

The cancer diagnosis disclosure for the patient and healthcare professionals

The disclosure of the cancer diagnosis is considered a crucial moment and the way healthcare professionals communicate it interferes directly in patient's relationship with his/her diagnosis. The study aims to discuss about the importance of the disclosure of the cancer diagnosis for the patient and for the health professionals. The methodology is an essay. The discussion begins with works perspectives which involves health professionals' interaction with the patient and cancer diagnosis disclosure presenting the difficulties lived by both as well as nursing performance in this process. The difficult task of revealing the diagnosis can diverge in each one's experience field and health professionals should be prepared to act in an effective way by taking into account patient's cultural, social and psychological background related to the way the information is communicated to them.     

Chlamydia trachomatis in the conjunctiva of children living in three rural areas in Mexico.

OBJECTIVES: Chlamydia trachomatis infections, in the context of extreme poverty, may trigger trachoma. Because the levels of C. trachomatis eye infections in Mexico are unknown, this study sought to determine if C. trachomatis was present in the conjunctiva of children living in three poor, rural areas of the country. METHODS: Clinical diagnosis of conjunctival follicles in children was conducted during the 2004 visual acuity assessment campaigns in rural areas of the states of Chiapas, Oaxaca, and Zacatecas. C. trachomatis detection was carried out by sampling the children with follicles and examining the specimens after Giemsa or microimmunofluorescence (MIF) staining. RESULTS: A total of 941 children from 6 to 12 years of age were examined in 2004. Of the 484 in Chiapas, 30% were found to have follicles; of the 181 in Zacatecas, 22%; and of the 276 in Oaxaca, 42%. C. trachomatis was detected at levels ranging between 2% and 5%; positive by Giemsa in 4.5% of the children with follicles, and by MIF in 15.5%. CONCLUSIONS: Considering that the chlamydiae sampling procedures and detection methods used in this study were not the most sensitive, the results underestimate the chlamydial eye infections and represent a conservative assessment of a potential risk for preventable visual impairment. Because C. trachomatis was detected here at levels similar to those reported for low-endemic trachoma areas, health authorities should be prepared to implement appropriate measures should it be confirmed that the visual health of Mexico's children is at risk.     

Measurement of body fat by dual-energy X-ray absorptiometry and bioimpedance analysis in men with prostate cancer

OBJECTIVE: The aims of this study were to determine the percentage of body fat (%BF) by dual-energy x-ray absorptiometry (DXA) and bioelectrical impedance analysis (BIA) using a standard adult equation and BIA using a standard geriatric equation in a population of older men with prostate cancer and to compare the results from these different methods. METHODS: We conducted a cross-sectional study in 38 men with locally advanced, node-positive, or recurrent prostate cancer and no history of androgen-deprivation therapy. Body composition was evaluated by DXA with the use of a Hologic 4500A densitometer and BIA. BIA %BF was calculated by using standard equations developed for adult and geriatric populations. RESULTS: %BF by DXA, BIA with the standard adult equation, BIA with the standard geriatric equation, and BIA with the age-appropriate equation were 26.7 +/- 5.3%, 22.5 +/- 5.6%, 38.2 +/- 6.9%, and 35.4 +/- 9.6%, respectively. There were statistically significant differences between %BF by DXA and all BIA estimates. By using the methods described by Bland and Altman (Lancet 1986;1(8476):307), the standard adult equation showed the least bias and variability. CONCLUSIONS: In this group of men with prostate cancer, BIA with the standard adult equation provided a reasonable estimate of %BF compared with DXA, although the differences were statistically significant. BIA with the standard geriatric equation, however, markedly overestimated %BF compared with DXA, even when its use was restricted to elderly men.     

The experience of thalassemic adults with their treatment

This study, based on medical anthropology and oral reports, analyzes the meanings attributed by thalassemic adults to their experiences with the treatment. Interviews were used to collect data, which were analyzed through inductive thematic analysis. Eleven young adults, six of whom were men, at different ages, with different educational levels and occupations participated in the study. The meanings are discussed through the theme "the lives of patients with thalassemia in relation to their treatment". This core meaning highlights the difference made in their identity by having the disease trait, the recognition of the importance of adhering to their treatment, the difficulties in maintaining their social functions, the patients' irregular treatment adherence and their justifications for non-adherence to their treatment. Thalassemic patients conform to their condition and employ a normalization strategy to control the disease and justify irregular treatment adherence.