HIV/AIDS communication among adolescents in psychiatric care and their parents.

The authors examined HIV/AIDS communication among 207 parent-adolescent dyads in psychiatric care to better understand the relationship between family communication and sexual risk behavior in an at-risk population. Dyads reported content and rated quality of family HIV/AIDS discussions, and adolescent sexual risk was assessed. Families discussed transmission, prevention, consequences, myths, and compassion. Parent-reported discussion of consequences was associated with greater sexual risk behavior, but only for girls. Higher quality communication reported by adolescents was associated with less sexual risk. Parents may send different messages about HIV/AIDS to sons versus daughters, and messages related to consequences may not effectively reduce risk among daughters. However, for boys and girls in psychiatric care, teaching parents how to discuss HIV/AIDS may promote safer sexual behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Measurement of smoking outcome expectancies in children: The Smoking Consequences Questionnaire-Child.

A measure of smoking outcome expectancies was developed for children ages 7-12 years. Confirmatory factor analysis (CFA) was used to determine whether a 1-, 2-, 3-, or 4-factor solution was most appropriate for the data set. CFA revealed that the 3-factor model produced the most adequate fit (Positive Reinforcement, Negative Consequences, and Weight Control). The resulting 15-item measure was named the Smoking Consequences Questionnaire-Child (SCQ-C). The fit of the 3-dimensional structure was then examined separately for 3 age groups representing young (7- to 8-year-old), middle (9- to 10-year-old), and old (11- to 13-year-old) children. Overall, the 3-factor structure fit the data well for the 3 groups. As such, we examined the relations of the 3 scales with antecedent variables for the entire sample. The Positive Reinforcement scale was associated with children's smoking behavior and having a family member or peers who smoked. The Negative Consequences scale was inversely related to having a family member or peer who smoked. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Using Human Perceptual Categories for Content-Based Retrieval from a Medical Image Database

It is often difficult to come up with a well-principled approach to the selection of low-level features for characterizing images for content-based retrieval. This is particularly true for medical imagery, where gross characterizations on the basis of color and other global properties do not work. An alternative for medical imagery consists of the “scattershot” approach that first extracts a large number of features from an image and then reduces the dimensionality of the feature space by applying a feature selection algorithm such as the Sequential Forward Selection method.This contribution presents a better alternative to initial feature extraction for medical imagery. The proposed new approach consists of (i) eliciting from the domain experts (physicians, in our case) the perceptual categories they use to recognize diseases in images; (ii) applying a suite of operators to the images to detect the presence or the absence of these perceptual categories; (iii) ascertaining the discriminatory power of the perceptual categories through statistical testing; and, finally, (iv) devising a retrieval algorithm using the perceptual categories. In this paper we will present our proposed approach for the domain of high-resolution computed tomography (HRCT) images of the lung. Our empirical evaluation shows that feature extraction based on physicians' perceptual categories achieves significantly higher retrieval precision than the traditional scattershot approach. Moreover, the use of perceptually based features gives the system the ability to provide an explanation for its retrieval decisions, thereby instilling more confidence in its users.     

Complex formation of divalent metal ions with uridine 5'-O-thiomonophosphate or methyl thiophosphate: comparison of complex stabilities with those of the parent phosphate ligands

The stability constants of the 1:1 complexes formed in aqueous solution between Mg2+, Ca2+, Sr2+, Ba2+, Mn2+, Co2+, Ni2+, Zn2+, or Cd2+ (M2+) and methyl thiophosphate (MeOPS(2-)) or uridine 5'-O-thiomonophosphate (UMPS(2-)) (PS(2-)=MeOPS(2-) or UMPS(2-)) have been determined (potentiometric pH titrations; 25 degrees C; I = 0.1 M, NaNO(3)). Comparison of these results for M(PS) complexes with those known for the parent M(PO) phosphate species, where PO(2-)=CH(3)OPO(2-)(3) or UMP(2-) (uridine 5'-monophosphate), shows that the alkaline earth metal ions, as well as Mn2+, Co2+, and Ni2+ have a higher affinity for phosphate groups than for their thio analogues. However, based on the linear log K(M)(M(R-PO3)) versus pK(H)(H(R-PO3)) relationships (R-PO(2-)(3) simple phosphate monoester or phosphonate ligands with a non-interacting residue R) it becomes clear that the indicated observation is only the result of the lower basicity of the thiophosphate residue. In contrast, the thio complexes of Zn2+ and Cd2+ are more stable than their parent phosphate ones, and this despite the lower basicity of the PS(2-) ligands. This stability increase is identical for M(MeOPS) and M(UMPS) species and amounts to about 0.6 and 2.4 log units for Zn(PS) and Cd(PS), respectively. Since no other binding site is available in MeOPS(2-), this enhanced stability has to be attributed to the S atom. Indeed, from the mentioned stability differences it follows that Cd2+ in Cd(PS) is coordinated by more than 99% to the thiophosphate S atom; the same value holds for Pb(PS), which was studied earlier. The formation degree of the Sbonded isomer amounts to 76+/-6 % for Zn(PS) and is close to zero for the corresponding Mg2+, Ca2+, and Mn2+ species. It is further shown that Zn(MeOPS)(aq)(2+) releases a proton from a coordinated water molecule with pK(a) approximately 6.9; i.e., this deprotonation occurs at a lower pH value than that for the same reaction in Zn(aq)(2+). Since Mg2+, Ca2+, Mn2+, and Cd2+ have a relatively low tendency for hydroxo complex formation, it was possible, for these M2+, to also quantify the stability of the binuclear complexes, M(2)(UMPS-H)+, where one M2+ is thiophosphate-coordinated and the other is coordinated at (N3)(-) of the uracil residue. The impact of the results presented herein regarding M2+/nucleic acid interactions, including those of ribozymes (rescue experiments), is briefly discussed.     

Conformational features of human melanin-concentrating hormone: an NMR and computational analysis

The conformational features of human melanin-concentrating hormone (hMCH) [Asp1-Phe2-Asp3-Met4-Leu5-Arg6-cyclo(S[bond]S)(Cys7-Met8-Leu9-Gly10-Arg11-Val12-Tyr13-Arg14-Pro15-Cys16)-Trp17-Gln18-Val19], in water and in a CD(3)CN/H(2)O (1:1 v/v) mixture at 298 K, have been determined by NMR spectroscopy followed by simulated annealing and molecular dynamics analyses to identify conformer populations. Backbone clustering analysis of NMR-spectroscopy-derived structures in the 7-16 peptide region led to the identification of a single representative structure in each solvent. Both root mean square deviation clustering and secondary structure analysis of the final conformers in both solvents show substantial convergence of most conformers into a single fold in the 4-17 region, with a limited variability around Gly10 and Tyr13 on going from CD(3)CN/H(2)O to pure water. The main feature deduced from the analysis of secondary structures is the occurrence of an N-terminal alpha helix of variable length, which spans an overall residue range of 2-9. A comparative analysis in the two solvents highlights that these structures are substantially different from that reported in the literature for the cyclic MCH(5-14) subunit of salmon MCH, which was used to perform a molecular characterization of the MCH/receptor complex. Our conformational data call for a critical revision of the proposed MCH/receptor complex model.     

Neurotrophin Trk receptors in the brain of a teleost fish, Nothobranchius furzeri

Trk neurotrophin receptors are transmembrane tyrosine kinase proteins known as TrkA, TrkB, and TrkC. TrkA is the high affinity receptor for nerve growth factor, TrkB is the one for both brain-derived neurotrophic factor and neurotrophin-4, and TrkC is the preferred receptor for neurotrophin-3. In the adult mammalian brain, neurotrophins are important regulators of neuronal function and plasticity. This study is based on Nothobranchius furzeri, a teleost fish that is becoming an ideal candidate as animal model for aging studies because its life expectancy in captivity is of just 3 months. In adult N. furzeri, all three investigated neurotrophin Trk receptors were immunohistochemically detected in each brain region. TrkA positive neuronal perikarya were localized in the dorsal and ventral areas of the telencephalon and in the cortical nucleus; TrkB immunoreactivity was observed in neuronal perikarya of the dorsal and ventral areas of the telencephalon, the diffuse inferior lobe of the hypothalamus, and Purkinje cells; TrkC positive neuronal perikarya were detected in the most aboral region of the telencephalon, in the magnocellular preoptic nucleus and in few neurons dispersed in the hypothalamus. Numerous positive fibers were widely distributed throughout the brain. Radial glial cells lining the mesencephalic and rhombencephalic ventricles showed immunoreactivity to all three Trks. These findings suggest an involvement of neurotrophins in many aspects of biology of adult N. furzeri.     

Affording Mechanisms: An Integrated View of Coordination and Knowledge Management

In this paper we question the separation between technologies that support information and handle the ordered flow of work and technologies that support knowledge management. On the basis of observational studies and initiatives of participatory prototype design that we performed in the hospital domain and other cooperative work settings, the paper proposes a unified view of these high-level functionalities through the notion of Affording Mechanism. In order to clarify the implications for design, the paper discusses the relationships between knowledge and representations; the role of artifacts that are used in activities where knowledge is allegedly “produced, shared and consumed”; and finally the notion of affordance and its dynamics. In very general terms, an AM consists of an artifact and of dynamic relationships between the context of use and the artifact’s affordances, expressed in terms of simple if-then constructs. The affordances conveyed through and by the artifact are modulated in order to evoke a “positive” reaction in the actors who use these augmented artifacts and to support knowledgeable behaviors apt to the situation. Moreover, the paper illustrates a prototypical technology through examples derived from the studies mentioned above, and discusses the kind of support this application provides in the light of an unusual interpretation of what it might mean to “manage” knowledge through computer-based technology.     

A systematic literature review of stakeholder identification methods in requirements elicitation

This paper presents a systematic review of relevant published studies related to topics in Requirements Engineering, specifically, concerning stakeholder identification methods in requirements elicitation, dated from 1984 to 2011. Addressing four specific research questions, this systematic literature review shows the following evidence gathered from these studies: current status of stakeholder identification in software requirement elicitation, the best practices recommended for its performance, consequences of incorrect identification in requirements quality, and, aspects which need to be improved. Our findings suggest that the analyzed approaches still have serious limitations in terms of covering all aspects of stakeholder identification as an important part of requirements elicitation. However, through correctly identifying and understanding the stakeholders, it is possible to develop high quality software.