Making tracks in metals

Swift heavy ions lose energy primarily by inelastic electronic scattering and, above an energy threshold, electronic losses result in damage to the lattice. Such high energy radiation is beyond the range of validity of traditional cascade simulations, and predictive damage calculations are challenging. We use a novel methodology, which combines molecular dynamics with a consistent treatment of electronic energy transport and redistribution to the lattice, to model how swift heavy ions form damage tracks. We consider a range of material parameters (electron-phonon coupling strength, thermal conductivity and electronic specific heat) and show how these affect the maximum lattice temperature reached and the extent of residual damage. Our analysis also suggests that fission tracks may form in alloys of archaeological interest

Breastfeeding Perceptions, Rates of Initiation, and Duration Among Urban and Rural Women

Breastfeeding is the optimal feeding method for infants up to the age of 2. Breast milk is suited to fulfill the nutritional needs of infants while providing immunological and neurological benefits. Breastfeeding rates of initiation and duration are low in the United States, especially in the state of Georgia. The purpose of this cross-sectional study was to investigate how breastfeeding initiation and duration, self-efficacy, perceptions, and community breastfeeding resources differ based on geographical location. The social ecological model was used as the theoretical framework for this study. An online and in-person survey that combined the Iowa Feeding Attitude Scale, Breastfeeding Self-Efficacy Questionnaire and The Breastfeeding in Public Survey was administered to 150 English speaking mothers aged 18 and older with a child 1 year or younger. The research questions were addressed using various statistical analyses (crosstabs, Mann Whitney U-test, and t test). The study results showed no differences in the odds of breastfeeding initiation and duration among mothers in urban and rural Georgia. No differences in breastfeeding perception or the use of breastfeeding community resources were observed. The results of this study contribute to social change by identifying the need to develop breastfeeding interventions that will address breastfeeding perceptions, community resources, and breastfeeding self-efficacy in urban and rural areas

Preterm nutritional intake and MRI phenotype at term age: a prospective observational study

Objective: To describe (1) the relationship between nutrition and the preterm-at-term infant phenotype, (2) phenotypic differences between preterm-at-term infants and healthy term born infants and (3) relationships between somatic and brain MRI outcomes. Design: Prospective observational study. Setting: UK tertiary neonatal unit. Participants: Preterm infants (<32 weeks gestation) (n=22) and healthy term infants (n=39) Main outcome measures: Preterm nutrient intake; total and regional adipose tissue (AT) depot volumes; brain volume and proximal cerebral arterial vessel tortuosity (CAVT) in preterm infants and in term infants. Results: Preterm nutrition was deficient in protein and high in carbohydrate and fat. Preterm nutrition was not related to AT volumes, brain volume or proximal CAVT score; a positive association was noted between human milk intake and proximal CAVT score (r=0.44, p=0.05). In comparison to term infants, preterm infants had increased total adiposity, comparable brain volumes and reduced proximal CAVT scores. There was a significant negative correlation between deep subcutaneous abdominal AT volume and brain volume in preterm infants (r=−0.58, p=0.01). Conclusions: Though there are significant phenotypic differences between preterm infants at term and term infants, preterm macronutrient intake does not appear to be a determinant. Our preliminary data suggest that (1) human milk may exert a beneficial effect on cerebral arterial vessel tortuosity and (2) there is a negative correlation between adiposity and brain volume in preterm infants at term. Further work is warranted to see if our findings can be replicated and to understand the causal mechanisms

Animal models of leukodystrophy : a new perspective for the development of therapies

The leukodystrophies are a family of heritable disorders characterised by white matter degeneration, accompanied by variable clinical symptoms including loss of motor function and cognitive decline. Now thought to include over fifty distinct disorders, there are a vast array of mechanisms underlying the pathology of these monogenic conditions and, accordingly, a range of animal models relating to each disorder. While both murine and zebrafish models continue to aid in the development of potential therapies, many of these models fail to truly recapitulate the human condition—thus leaving substantial weaknesses in our understanding of leukodystrophy pathogenesis. Additionally, the heterogeneity in leukodystrophy presentation—both in patients and in vivo models—often results in a narrow focus on single disorders in isolation across much of the literature. Thus, this review aims to synthesise prominent research regarding the most common leukodystrophies in order to provide an overview of key animal models and their utility in developing novel treatments. We begin by discussing the ongoing revolution across the leukodystrophy field following the rise of next generation sequencing, before focusing more extensively on existing animal models from the mouse and zebrafish fields. Finally, we explore how these pre‐clinical models have shaped the development of therapeutic strategies currently in development. We propose future directions for the field and suggest a more critical view of the dogma which has underpinned leukodystrophy research for decades

Sales and Operations Planning (S&OP): A Group Effectiveness Approach

Sales and Operations planning (S&OP) is an approach meant to help firms achieve demand and supply balance, yet experts agree that it has fallen short on delivering anticipated benefits. Carried out by cross-functional teams, S&OP entails getting people from different thought worlds, especially sales, aligned around common goals. Despite ample practitioner guidance, there is a dearth of scholarly research indicating pathways to success. Using a group effectiveness theoretical framework, this study identifies both internal team factors and contextual influencers that are predictors of S&OP effectiveness. Perspectives were captured from S&OP team members across a wide cross-section of industries representing sales and operations functions using a survey-based approach. Results indicate that internal team factors of social cohesion and decision making autonomy are key drivers of collaboration. Similarly, information quality, procedural quality, and team-based rewards/incentives serve as contextual influencers of collaboration. In turn, collaboration serves as a central mediator, partially linking antecedents to S&OP effectiveness and also serving as a direct influencer of success. Moreover, having joint rewards and incentives, which is often not the case among S&OP teams, is the greatest overall driver of S&OP effectiveness. Overall, these findings provide empirically-based guidance for managers seeking to determine which factors are most important for S&OP team success. Additionally, grounding S&OP in principles of group effectiveness theory will also aid future academic study in efforts to help firms achieve greater demand and supply balance

Modularity and composite diversity affect the collective gathering of information online

Many modern interactions happen in a digital space, where automated recommendations and homophily can shape the composition of groups interacting together and the knowledge that groups are able to tap into when operating online. Digital interactions are also characterized by different scales, from small interest groups to large online communities. Here, we manipulate the composition of groups based on a large multi-trait profiling space (including demographic, professional, psychological and relational variables) to explore the causal link between group composition and performance as a function of group size. We asked volunteers to search news online under time pressure and measured individual and group performance in forecasting real geo-political events. Our manipulation affected the correlation of forecasts made by people after online searches. Group composition interacted with group size so that composite diversity benefited individual and group performance proportionally to group size. Aggregating opinions of modular crowds composed of small independent groups achieved better forecasts than aggregating a similar number of forecasts from non-modular ones. Finally, we show differences existing among groups in terms of disagreement, speed of convergence to consensus forecasts and within-group variability in performance. The present work sheds light on the mechanisms underlying effective online information gathering in digital environments

No classical limit of quantum decay for broad states

Though the classical treatment of spontaneous decay leads to an exponential decay law, it is well known that this is an approximation of the quantum mechanical result which is a non-exponential at very small and large times for narrow states. The non exponential nature at large times is however hard to establish from experiments. A method to recover the time evolution of unstable states from a parametrization of the amplitude fitted to data is presented. We apply the method to a realistic example of a very broad state, the sigma meson and reveal that an exponential decay is not a valid approximation at any time for this state. This example derived from experiment, shows the unique nature of broad resonances