The Application of Transformational Leadership Theory to Parenting: Questionnaire Development and Implications for Adolescent Self-Regulatory Efficacy and Life Satisfaction

We draw upon transformational leadership theory to develop an instrument to measure transformational parenting for use with adolescents. First, potential items were generated that were developmentally appropriate and evidence for content validity was provided through the use of focus groups with parents and adolescents. We subsequently provide evidence for several aspects of construct validity of measures derived from the Transformational Parenting Questionnaire (TPQ). Data were collected from 857 adolescents (Mage = 14.70 years), who rated the behaviors of their mothers and fathers. The results provided support for a second-order measurement model of transformational parenting. In addition, positive relationships between mothers’ and fathers’ transformational parenting behaviors, adolescents’ self-regulatory efficacy for physical activity and healthy eating, and life satisfaction were found. The results of this research support the application of transformational leadership theory to parenting behaviors, as well as the construct validity of measures derived from the TPQ. (AUTHORS' ABSTRACT

Dynamics of Uptake and Metabolism of Small Molecules in Cellular Response Systems

BACKGROUND: Proper cellular function requires uptake of small molecules from the environment. In response to changes in extracellular conditions cells alter the import and utilization of small molecules. For a wide variety of small molecules the cellular response is regulated by a network motif that combines two feedback loops, one which regulates the transport and the other which regulates the subsequent metabolism. RESULTS: We analyze the dynamic behavior of two widespread but logically distinct two-loop motifs. These motifs differ in the logic of the feedback loop regulating the uptake of the small molecule. Our aim is to examine the qualitative features of the dynamics of these two classes of feedback motifs. We find that the negative feedback to transport is accompanied by overshoot in the intracellular amount of small molecules, whereas a positive feedback to transport removes overshoot by boosting the final steady state level. On the other hand, the negative feedback allows for a rapid initial response, whereas the positive feedback is slower. We also illustrate how the dynamical deficiencies of one feedback motif can be mitigated by an additional loop, while maintaining the original steady-state properties. CONCLUSIONS: Our analysis emphasizes the core of the regulation found in many motifs at the interface between the metabolic network and the environment of the cell. By simplifying the regulation into uptake and the first metabolic step, we provide a basis for elaborate studies of more realistic network structures. Particularly, this theoretical analysis predicts that FeS cluster formation plays an important role in the dynamics of iron homeostasis

Caractérisation des risques de contamination des agrosystèmes périurbains de Dakar par les éléments traces métalliques

L’application de produits résiduaires organiques (PRO) améliore la fertilité des sols, mais induit des effets négatifs sur les agrosystèmes, en raison de la présence de contaminants tels que les éléments traces métalliques (ETM). Cette étude vise à évaluer l’influence de deux doses (20 et 60 T.ha-1) d’apport de boue de station d’épuration STEP et de fiente de volaille sur la disponibilité de quatre ETM (Ni, Cd, Cr et Pb) dans un arenosol et un fluvisol. Une incubation de 88 jours en conditions contrôlées a été conduite sur les deux sols mélangés aux différentes doses de boue et de fiente. La disponibilité des ETM dans les sols incubés a été évaluée par la technique DGT (Diffusive Gradient in Thin films). Les boues ont abaissé le pH des deux sols tandis que les fientes ont alcalinisé l’arenosol durant les 14 premiers jours d’incubation. Ces PRO ont augmenté les concentrations de Ni, Cd, Pb et Cr disponibles dans les sols. Les  disponibilités du Ni, Cd et Pb sont plus élevées dans l’arenosol que dans le fluvisol. La boue à 60 T.ha-1 a induit les plus fortes disponibilités en Cd et Pb tandis que la fiente à 60 T.ha-1 a induit les plus fortes disponibilités en Ni et Cr dans les deux sols.Mots clés : Eléments traces métalliques, arenosol, fluvisol, boue d’épuration, fiente.  CHARACTERIZATION OF CONTAMINATION RISKS OF THE  SUBURBANAGROECOSYSTEMS OF DAKAR BY TRACE ELEMENTSOrganic wastes (OW) spreading improve soil fertility, but can induce negative effects on agroecosystems, due to the presence of contaminants such as trace elements (TE). This study aims to evaluate the impacts of two doses (20 and 60 T.ha-1) of sewage sludge and poultry manure on the availability of four trace elements (Ni, Cd, Cr and Pb) in arenosol and  fluvisol. Soils mixed with different doses of sewage sludge and poultry manure were incubated for 88 days under controlled conditions. The  availability of trace elements in incubated soils was evaluated by the DGT (Diffusive Gradient in Thin films) technique. Sewage sludge has decreased the pH of both soils while poultry manure induced an alkalinization of arenosol during the first 14 days of incubation. OW increased Ni, Cd, Pb and Cr availability in the soils. Availability of Ni, Cd and Pb were higher in arenosol than in the fluvisol. Sewage sludge at 60 T.ha-1 induced the highest availability of Cd and Pb while the poultry manure at 60 T.ha-1 induced the highest availability of Ni and Cr in both soils.Keywords : Trace elements, arenosol, fluvisol, sewage sludge, poultry manure

The enpp4 ectonucleotidase regulates kidney patterning signalling networks in Xenopus embryos

Abstract The enpp ectonucleotidases regulate lipidic and purinergic signalling pathways by controlling the extracellular concentrations of purines and bioactive lipids. Although both pathways are key regulators of kidney physiology and linked to human renal pathologies, their roles during nephrogenesis remain poorly understood. We previously showed that the pronephros was a major site of enpp expression and now demonstrate an unsuspected role for the conserved vertebrate enpp4 protein during kidney formation in Xenopus . Enpp4 over-expression results in ectopic renal tissues and, on rare occasion, complete mini-duplication of the entire kidney. Enpp4 is required and sufficient for pronephric markers expression and regulates the expression of RA, Notch and Wnt pathway members. Enpp4 is a membrane protein that binds, without hydrolyzing, phosphatidylserine and its effects are mediated by the receptor s1pr5, although not via the generation of S1P. Finally, we propose a novel and non-catalytic mechanism by which lipidic signalling regulates nephrogenesis

Choice of activity-intensity classification thresholds impacts upon accelerometer-assessed physical activity-health relationships in children

It is unknown whether using different published thresholds (PTs) for classifying physical activity (PA) impacts upon activity-health relationships. This study explored whether relationships between PA (sedentary [SED], light PA [LPA], moderate PA [MPA], moderate-to-vigorous PA, vigorous PA [VPA]) and health markers differed in children when classified using three different PTs

Chemical and biomechanical characterization of hyperhomocysteinemic bone disease in an animal model

BACKGROUND: Classical homocystinuria is an autosomal recessive disorder caused by cystathionine β-synthase (CBS) deficiency and characterized by distinctive alterations of bone growth and skeletal development. Skeletal changes include a reduction in bone density, making it a potentially attractive model for the study of idiopathic osteoporosis. METHODS: To investigate this aspect of hyperhomocysteinemia, we supplemented developing chicks (n = 8) with 0.6% dl-homocysteine (hCySH) for the first 8 weeks of life in comparison to controls (n = 10), and studied biochemical, biomechanical and morphologic effects of this nutritional intervention. RESULTS: hCySH-fed animals grew faster and had longer tibiae at the end of the study. Plasma levels of hCySH, methionine, cystathionine, and inorganic sulfate were higher, but calcium, phosphate, and other indices of osteoblast metabolism were not different. Radiographs of the lower limbs showed generalized osteopenia and accelerated epiphyseal ossification with distinct metaphyseal and suprametaphyseal lucencies similar to those found in human homocystinurics. Although biomechanical testing of the tibiae, including maximal load to failure and bone stiffness, indicated stronger bone, strength was proportional to the increased length and cortical thickness in the hCySH-supplemented group. Bone ash weights and IR-spectroscopy of cortical bone showed no difference in mineral content, but there were higher Ca(2+)/PO(4)(3- )and lower Ca(2+)/CO(3)(2- )molar ratios than in controls. Mineral crystallization was unchanged. CONCLUSION: In this chick model, hyperhomocysteinemia causes greater radial and longitudinal bone growth, despite normal indices of bone formation. Although there is also evidence for an abnormal matrix and altered bone composition, our finding of normal biomechanical bone strength, once corrected for altered morphometry, suggests that any increase in the risk of long bone fracture in human hyperhomocysteinemic disease is small. We also conclude that the hCySH-supplemented chick is a promising model for study of the connective tissue abnormalities associated with homocystinuria and an important alternative model to the CBS knock-out mouse

Long-lived photoexcited states in polydiacetylenes with different molecular and supramolecular organization

With the aim of determining the importance of the molecular and supramolecular organization on the excited states of polydiacetylenes, we have studied the photoinduced absorption spectra of the red form of poly[1,6-bis(3,6-didodecyl-N-carbazolyl)-2,4-hexadiyne] (polyDCHD-S) and the results compared with those of the blue form of the same polymer. An interpretation of the data is given in terms of both the conjugation length and the interbackbone separation also in relation to the photoinduced absorption spectra of both blue and red forms of poly[1,6-bis(N-carbazolyl)-2,4-hexadiyne] (polyDCHD), which does not carry the alkyl substituents on the carbazolyl side groups. Information on the above properties is derived from the analysis of the absorption and Raman spectra of this class of polydiacetylenes