Parental correlates of children's peer relations: An empirical test of a tripartite model.

In recognition of the multiple pathways through which family and peer systems are linked, this short-term longitudinal study tested a tripartite model of family-peer relationships. One hundred fifty-nine fourth-grade children (82 boys, 77 girls) and their parents participated in a study of the links between parent behaviors and children's peer relations both concurrently and 1 year later. A multimethod approach--including observations of parent?child interactions, parent report, child report, and teacher and peer ratings--was used to evaluate a tripartite model of family-peer relations. Results indicate that parent?child interaction, parent advice giving, and parental provision of opportunities by both mothers and fathers predict children's social competence and, in turn, social acceptance 1 year later. Suggestions for future research and practical implications are noted, and limitations of the study are acknowledged. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Slowed enzymatic turnover allows characterization of intermediates by solid-state NMR

EPSP (5-enolpyruvylshikimate-3-phosphate) synthase catalyzes condensation of shikimate 3-phosphate (S3P) and phosphoenolpyruvate (PEP) to form EPSP, a precursor to the aromatic amino acids. S3P and [2-13C]POP were bound to mutant or wild type E. coli forms of the enzyme prior to lyophilization. CPMAS-echo and rotational-echo double-resonance (REDOR) NMR experiments, employing a slow catalytic EPSP synthase mutant and a long prelyophilization incubation interval, allowed our observation of the gradual formation of a strong 31P-13C coupling consistent with the well characterized tetrahedral intermediate. However, after shorter low temperature incubation intervals of substrates with mutant or wild-type enzymes, carbon CPMAS-echo NMR spectra showed the 13C label at 155 ppm, consistent with sp2 geometry of this carbon. REDOR revealed that the phosphorus of PEP was cleaved. However, phosphorus at a distance of 7.5 A was observed, due to the phosphate of a nearby bound S3P. Heating the sample allowed the reaction to progress, as shown by the diminution of the 155 ppm peak and growth of a peak at 108 ppm. The sp3 geometry implied by the 108 ppm peak strongly suggested formation of a S3P-PEP condensation product. REDOR indicated that phosphorus was still distant, but now only 6.1 (wild type) or 5.9 A (mutant) distant. We think that the early intermediates with peaks at 155 and 108 ppm are covalently bound to the enzyme. We also think that the tetrahedral intermediate that we observed was formed after product was generated.     

Chemical nature and potential mobility of phosphorus in fertilized grassland soils

This paper describes results from a study of the effects of various applications of phosphorus (P) on the amounts, forms and potential mobility of P in grassland soils (0-7.5 cm) collected from four locations in the United Kingdom (Hertfordshire, Devon) and New Zealand (Taranaki, Canterbury). A sequential extraction scheme (NH₄Cl, NH₄F, NaOH I, H₂SO₄, NaOH II, residual P) designed to isolate P associated with aluminium (Al), iron (Fe) and calcium (Ca) was used to characterise P in the grassland soils from each location which had received various quantities of mineral fertilizer, organic manure and lime. Concentrations of total P in the soils ranged from 540 to 3,994 mg P kg^-1, and sequential extraction recovered 80–94% of total soil P. Extractable forms of inorganic P and organic P accounted for 40–52% and 31–50% of total soil P respectively. Inorganic and organic P present in the NaOH I fraction (P associated with Fe, Al and organic matter) accounted for most of the P which accumulated in soil from P inputs. Distribution of accumulated soil P between the various inorganic and organic P fractions appeared to be mainly controlled by the nature and availability of sorption surfaces which act as sinks for inorganic P. Phosphate sorption index data for the various soil sets indicated that the mean value of bicarbonate extractable inorganic P (Olsen P) which represented effective P saturation ranged from 61 to 217 mg P kg^-1. Potentially mobile soil P as determined by extraction with 0.01M calcium chloride (CaCl₂) was found to be most strongly correlated to the NH₄F, NaOH I and H₂SO₄ inorganic P fractions using a Freundlich isotherm.     

New Experimental Evidence about the Dyeing of Polyester Materials with Disperse Dyes

It is shown for the polyester-water-disperse dye system that the thermodynamic parameters obtained from sorption data can differ from those obtained from the saturation solubilities of the dye in the two phases. The difference is due to deviations from linearity in the sorption isotherms. The causes of these deviations for disperse dyes on polyester materials are discussed in some detail.     

Behavioral vs drug treatment for urge urinary incontinence in older women: a randomized controlled trial

CONTEXT: Urinary incontinence is a common condition caused by many factors with several treatment options. OBJECTIVE: To compare the effectiveness of biofeedback-assisted behavioral treatment with drug treatment and a placebo control condition for the treatment of urge and mixed urinary incontinence in older community-dwelling women. DESIGN: Randomized placebo-controlled trial conducted from 1989 to 1995. SETTING: University-based outpatient geriatric medicine clinic. PATIENTS: A volunteer sample of 197 women aged 55 to 92 years with urge urinary incontinence or mixed incontinence with urge as the predominant pattern. Subjects had to have urodynamic evidence of bladder dysfunction, be ambulatory, and not have dementia. INTERVENTION: Subjects were randomized to 4 sessions (8 weeks) of biofeedback-assisted behavioral treatment, drug treatment (with oxybutynin chloride, possible range of doses, 2.5 mg daily to 5.0 mg 3 times daily), or a placebo control condition. MAIN OUTCOME MEASURES: Reduction in the frequency of incontinent episodes as determined by bladder diaries, and patients' perceptions of improvement and their comfort and satisfaction with treatment. RESULTS: For all 3 treatment groups, reduction of incontinence was most pronounced early in treatment and progressed more gradually thereafter. Behavioral treatment, which yielded a mean 80.7% reduction of incontinence episodes, was significantly more effective than drug treatment (mean 68.5% reduction; P=.04) and both were more effective than the placebo control condition (mean 39.4% reduction; P<.001 and P=.009, respectively). Patient-perceived improvement was greatest for behavioral treatment (74.1% "much better" vs 50.9% and 26.9% for drug treatment and placebo, respectively). Only 14.0% of patients receiving behavioral treatment wanted to change to another treatment vs 75.5% in each of the other groups. CONCLUSION: Behavioral treatment is a safe and effective conservative intervention that should be made more readily available to patients as a first-line treatment for urge and mixed incontinence.     

Interconnected silicon hollow nanospheres for lithium-ion battery anodes with long cycle life

Silicon is a promising candidate for the anode material in lithium-ion batteries due to its high theoretical specific capacity. However, volume changes during cycling cause pulverization and capacity fade, and improving cycle life is a major research challenge. Here, we report a novel interconnected Si hollow nanosphere electrode that is capable of accommodating large volume changes without pulverization during cycling. We achieved the high initial discharge capacity of 2725 mAh g(-1) with less than 8% capacity degradation every hundred cycles for 700 total cycles. Si hollow sphere electrodes also show a Coulombic efficiency of 99.5% in later cycles. Superior rate capability is demonstrated and attributed to fast lithium diffusion in the interconnected Si hollow structure.     

Role of sigma B factor in the alkaline tolerance response of Listeria monocytogenes 10403S and cross-protection against subsequent ethanol and osmotic stress

Many of the considerable abilities of Listeria monocytogenes to persist and grow in a wide range of adverse environmental conditions are thought to be at least partly under the control of the alternative sigma factor (sigmaB), encoded by the sigB gene. However, little is known about the role of this master regulon in the impressive ability of Listeria to persist and grow under conditions of alkaline pH. In this study, Northern blot analysis of parent Listeria mRNA revealed that alkali adaptation (pH 9.5 for 1 h) significantly increased the expression of sigB-derived mRNA. The study included a comparison of the relative survival of mid-exponential populations of adapted and nonadapted parent type (sigmaB expressing) and mutant (not sigmaB expressing, deltasigB) Listeria strains during subsequent alkaline (pH 12.0), osmotic (25% NaCl, wt/vol), or ethanol (16.5%) stress. Alkali-adapted parent strains were more resistant to pH 12.0 than were adapted deltasigB type strains, but both alkali-adapted parent and deltasigB strains were more resistant to pH 12.0 than were nonadapted strains. Alkali-adapted parent strains were more resistant to osmotic stress than were adapted deltasigB type strains. No significant differences in viability were observed between alkali-adapted parent and deltasigB strains after ethanol stress, suggesting that cross-protection against osmotic stress is mediated by sigmaB whereas cross-protection against ethanol is sigmaB independent. Overall, alkali-induced cross-protection against osmotic and ethanol challenges may have serious implications for food safety and human health because such stress conditions are routinely used as part of food preservation and surface cleaning processes.     

Cyclic loading of railway ballast under triaxial conditions and in a railway test facility

A recently developed large-scale triaxial test apparatus for railway ballast testing comprises a double-cell arrangement for measuring volume change by differential pressure. Monotonic and cyclic tests were performed on limestone ballast samples. Axial and volumetric strains and breakage were determined from both types of test. Resilient modulus and Poisson’s ratio were obtained only from the cyclic tests. The permanent axial strain and breakage results from the cyclic tests are compared with the simulated traffic loading in the railway test facility (RTF) which comprises three sleepers embedded in ballast over a subgrade. The traffic loading in the RTF was applied by hydraulic actuators with built-in displacement transducers. A column of painted ballast was placed under a rail seat of the middle sleeper to ease sample collection for sieve analysis at the end of the test. The stress condition in the RTF is predicted by a simple calculation based on findings of previous literature. It was found that the results from the cyclic triaxial test with conditions similar to the predicted conditions in the RTF were comparable to those results from the RTF tests.     

Continuum slip foundations of elasto-viscoplasticity

Summary A continuum slip theory for dislocation glide is employed to derive macroscopic, phenomenological models for incompressible viscoplasticity. The microstructural origins of kinematic/isotropic hardening and rate-dependence are examined within the framework of the continuum slip theory of Rice and the single slip scale invariance theory of Aifantis for dislocation glide. In the process, the limitations on primitive assumptions for existing forms of state variable viscoplasticity become apparent. A form for rate-dependent evolution of backstress is derived which supports recent phenomenological approaches. Extensions to finite strain and compressible viscoplasticity are discussed.