Technique for measuring metallic salt effects upon the indigenous heterotrophic microflora of a natural water

The effects of several concentrations of the metallic salts Ag₂SO₄, NaAsO₃, BaCl₂2H₂O, CdCl₂2.5 H₂O, CrCl₂6H₂O, CuCl₂, HgCl₂, NaCl, NiCl₂6H₂O, PbCl₂ and ZnCl₂ upon the indigenous heterotrophic microflora of a natural water were studied. Effects of these salts upon the heterotrophic activity of the microbes were assayed using the heterotrophic technique whereas lethal effects upon the heterotrophic bacteria were determined using nutrient agar plate counts. The heterotrophic activity method is based upon the uptake and mineralization of a radioactively labeled metabolite (in these experiments ¹⁴C-glucose) by the indigenous aquatic microbes and data analysis is by Michaelis—Menten enzyme kinetics equations. Concentrations of metallic salts which resulted in bacterial death also caused erratic uptake and mineralization rates of ¹⁴C-glucose whereas sub-lethal concentrations, as determined by nutrient agar plate counts, caused a non-competitive inhibition of maximum heterotrophic activity and markedly increased the turnover time of the glucose substrate.     

卢克索剧院,鹿特丹,荷兰

英雄式的现代主义致力于通过建筑建造一个个“乌托邦”,对这种现代主义的批判引发了当前面向日常生活主题的建筑潮流.它常常通过讽刺性的滑稽模仿触及现代建筑法则的痛处.卢克索剧院的设计在一定程度上是围绕观众进入剧院的路线展开的.观众从大街上进入剧院,盘旋而上到达不同楼层和环道端头的楼梯.环道环绕舞台和观众席而建,使观众席成为剧院的中心.这种便于观众流动的设计带给建筑的是一个自然的结构和无朝向性的外立面.外立面为纤维混凝土,这是一种普通的建筑材料.汽车坡道引人注目的大胆结构是所有建筑元素中最具挑战性的设计.     

X-ray diffraction line profile analysis of nanocrystalline graphite

The structure evolution to nanocrystalline graphite produced by ball milling in n-dodecane has been studied by Fourier analysis of broadened X-ray diffraction line profiles according to double-Voigt method. The Fourier analysis gave size and strain distributions of the coherently diffracting domains (X-ray crystallite size) and root-mean-square-strain (rmss) and their average values. The precursor graphite was defined by average crystal sizes of about hundreds of nanometers, measured along the in-plane and out-of-plane directions, and low rmss value of 0.38 × 10⁻³. During milling, the average crystallite sizes of graphite decreased to about 6 and 43 nm along the out-of-plane and in-plane directions, respectively. Correspondingly, the rmss of milled graphite increased to 6.54 × 10⁻³. Analysis of the out-of-plane to in-plane crystallite size ratios showed that the crystallites became progressively thinner and flatter. A linear relationship between rmss and reciprocal crystallite size along the stacking axis revealed that size of disordered boundary regions gradually increased at the expense of ordered crystalline regions. A model describing crystalline–nanocrystalline transformation of graphite along different crystallographic axis was formulated and used to discuss the experimental data. It was concluded that a distortion-controlled process is responsible for the crystalline–nanocrystalline transformation of graphite milled in n-dodecane.     

Predicting range performance of sampled imagers by treating aliased signal as target-dependent noise

This paper presents a new theory to predict the impact of sampling on target acquisition. The aliased signal that results from sampling is treated as noise. The aliased signal is different from detector noise in two ways. First, aliasing disappears as the target contrast decreases. Second, the image corruption due to aliasing gets worse with increased range. This is because sampling is constant in angle space, and targets become poorly sampled as range increases. The theory is presented, along with the results of three experiments. The match between model and experiment is excellent.     

Mechanisms for spatio-temporal pattern formation in highway traffic models

A key qualitative requirement for highway traffic models is the ability to replicate a type of traffic jam popularly referred to as a phantom jam, shock wave or stop-and-go wave. Despite over 50 years of modelling, the precise mechanisms for the generation and propagation of stop-and-go waves and the associated spatio-temporal patterns are in dispute. However, the increasing availability of empirical datasets, such as those collected from motorway incident detection and automatic signalling system (MIDAS) inductance loops in the UK or the next-generation simulation trajectory data (NGSIM) project in the USA, means that we can expect to resolve these questions definitively in the next few years. This paper will survey the essence of the competing explanations of highway traffic pattern formation and introduce and analyse a new mechanism, based on dynamical systems theory and bistability, which can help resolve the conflict.     

Age-related positivity enhancement is not universal: Older Chinese look away from positive stimuli.

Socioemotional selectivity theory postulates that with age, people are motivated to derive emotional meaning from life, leading them to pay more attention to positive relative to negative/neutral stimuli. The authors argue that cultures that differ in what they consider to be emotionally meaningful may show this preference to different extents. Using eye-tracking techniques, the authors compared visual attention toward emotional (happy, fearful, sad, and angry) and neutral facial expressions among 46 younger and 57 older Hong Kong Chinese. In contrast to prior Western findings, older but not younger Chinese looked away from happy facial expressions, suggesting that they do not show attentional preferences toward positive stimuli. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Collateral benefits of the family check-up on early childhood school readiness: Indirect effects of parents' positive behavior support.

The authors examined the longitudinal effects of the Family Check-Up (FCU) on parents' positive behavior support and children's school readiness competencies in early childhood. It was hypothesized that the FCU would promote language skills and inhibitory control in children at risk for behavior problems as an indirect outcome associated with targeted improvements in parents' positive behavior support. High-risk families in the Women, Infants, and Children Nutrition Program participated in a multisite preventive intervention study (N = 731) with 3 yearly assessments beginning at child age 2 years. Positive behavior support was measured using 4 indicators derived from at-home observations of parent-child interaction during semistructured tasks. Longitudinal structural equation models revealed that parents in families randomly assigned to the FCU showed improvements in positive behavior support from child age 2 to 3, which in turn promoted children's inhibitory control and language development from age 3 to 4, accounting for child gender, ethnicity, and parental education. Findings suggest that a brief, ecological preventive intervention supporting positive parenting practices can indirectly foster key facets of school readiness in children at risk. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reciprocal models of child behavior and depressive symptoms in mothers and fathers in a sample of children at risk for early conduct problems.

Although much has been written about transactional models in the study of parenting practices, relatively few researchers have used this approach to examine how child behavior might be related to parental well-being. This study used latent growth curve modeling to test transactional models of age 2 child noncompliance, parental depressive symptoms, and age 4 internalizing and externalizing behaviors using a subsample of families in the Early Steps Multisite Study. In unconditional models, maternal depressive symptoms showed a linear decrease from child ages 2 to 4, whereas paternal depression did not show significant change. Observed child noncompliance at age 2 showed significant associations with concurrent reports of maternal depressive symptoms and trend-level associations with paternal depressive symptoms. For both parents, higher levels of initial depressive symptoms were related to increased age 4 child internalizing behaviors. The findings provide support for reciprocal process models of parental depression and child behavior, and this study is one of the first to present empirical evidence that fathers' depressive symptoms have bidirectional associations with their children's behavior in early childhood. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Formation and effect of topologically close-packed phases in nickel-base superalloys

The formation of topologically close-packed (TCP) phases in nickel-base superalloys is an issue of increasing importance as alloys are designed with higher refractory element contents to meet the requirements of next generation turbine engines. This review considers the factors that affect an alloy’s susceptibility to TCP formation. In particular, the debate surrounding the effect of certain individual elements, such as Co and Re, in promoting or suppressing TCP formation is examined alongside the various mechanisms that have been proposed to account for this behaviour. In addition, the detrimental effects of these phases on the alloy’s mechanical properties are discussed, including crack initiation at precipitates, depletion of solid solution strengthening refractory elements and the effect on γ/γ′ rafting behaviour.

This review was chosen as a runner up of the 2016 Materials Literature Review Prize of the Institute of Materials, Minerals and Mining, run by the Editorial Board of MST. Sponsorship of the prize by TWI Ltd is gratefully acknowledged.