176 research outputs found
Vibrational Excitations in Weakly Coupled Single-Molecule Junctions: A Computational Analysis
In bulk systems, molecules are routinely identified by their vibrational
spectrum using Raman or infrared spectroscopy. In recent years, vibrational
excitation lines have been observed in low-temperature conductance measurements
on single molecule junctions and they can provide a similar means of
identification. We present a method to efficiently calculate these excitation
lines in weakly coupled, gateable single-molecule junctions, using a
combination of ab initio density functional theory and rate equations. Our
method takes transitions from excited to excited vibrational state into account
by evaluating the Franck-Condon factors for an arbitrary number of vibrational
quanta, and is therefore able to predict qualitatively different behaviour from
calculations limited to transitions from ground state to excited vibrational
state. We find that the vibrational spectrum is sensitive to the molecular
contact geometry and the charge state, and that it is generally necessary to
take more than one vibrational quantum into account. Quantitative comparison to
previously reported measurements on pi-conjugated molecules reveals that our
method is able to characterize the vibrational excitations and can be used to
identify single molecules in a junction. The method is computationally feasible
on commodity hardware.Comment: 9 pages, 7 figure
Configurations of mother-child and father-child attachment as predictors of internalizing and externalizing behavioral problems: An individual participant data (IPD) meta-analysis
An unsettled question in attachment theory and research is the extent to which children's attachment patterns with mothers and fathers jointly predict developmental outcomes. In this study, we used individual participant data (IPD) meta-analysis to assess whether early attachment networks with mothers and fathers are associated with children's internalizing and externalizing behavioral problems. Following a pre-registered protocol, data from 9 studies and 1,097 children (mean age: 28.67 months) with attachment classifications to both mothers and fathers were included in analyses. We used a linear mixed effects analysis to assess differences in children's internalizing and externalizing behavioral problems as assessed via the average of both maternal and paternal reports based on whether children had two, one, or no insecure (or disorganized) attachments. Results indicated that children with an insecure attachment relationship with one or both parents were at higher risk for elevated internalizing behavioral problems compared with children who were securely attached to both parents. Children whose attachment relationships with both parents were classified as disorganized had more externalizing behavioral problems compared to children with either one or no disorganized attachment relationship with their parents. Across attachment classification networks and behavioral problems, findings suggest (a) an increased vulnerability to behavioral problems when children have insecure or disorganized attachment to both parents, and (b) that mother-child and father-child attachment relationships may not differ in the roles they play in children's development of internalizing and externalizing behavioral problems
Polaritonic molecular clock for all-optical ultrafast imaging of wavepacket dynamics without probe pulses
Conventional approaches to probing ultrafast molecular dynamics rely on the use of synchronized laser pulses with a well-defined time delay. Typically, a pump pulse excites a molecular wavepacket. A subsequent probe pulse can then dissociate or ionize the molecule, and measurement of the molecular fragments provides information about where the wavepacket was for each time delay. Here, we propose to exploit the ultrafast nuclear-position-dependent emission obtained due to large light–matter coupling in plasmonic nanocavities to image wavepacket dynamics using only a single pump pulse. We show that the time-resolved emission from the cavity provides information about when the wavepacket passes a given region in nuclear configuration space. This approach can image both cavity-modified dynamics on polaritonic (hybrid light–matter) potentials in the strong light–matter coupling regime and bare-molecule dynamics in the intermediate coupling regime of large Purcell enhancements, and provides a route towards ultrafast molecular spectroscopy with plasmonic nanocavitiesThis work has been funded by the European Research Council grant ERC-2016-STG-714870 and the Spanish Ministry for Science, Innovation, and Universities—AEI grants RTI2018-099737-B-I00, PCI2018-093145 (through the QuantERA program of the European Commission), and CEX2018-000805-M (through the María de Maeztu program for Units of Excellence in R&D
Effectiveness and cost-effectiveness of referral to a commercial open group behavioural weight management programme in adults with overweight and obesity: 5-year follow-up of the WRAP randomised controlled trial
Background
There is evidence that commercially available behavioural weight management programmes can lead to short-term weight loss and reductions in glycaemia. Here, we aimed to provide the 5-year impact and cost-effectiveness of these interventions compared with a brief intervention.
Methods
WRAP was a non-blinded, parallel-group randomised controlled trial (RCT). We recruited from primary care practices in England and randomly assigned participants to one of three interventions (brief intervention, 12-week open-group behavioural programme [WW, formerly Weight Watchers], or a 52-week open-group WW behavioural programme) in an uneven (2:5:5) allocation. Participants were followed up 5 years after randomisation using data from measurement visits at primary care practices or a research centre, review of primary care electronic medical notes, and self-report questionnaires. The primary outcome was change in weight at 5 years follow-up, assessed using analysis of covariance. We also estimated cost-effectiveness of the intervention. This study is registered at Current Controlled Trials, ISRCTN64986150.
Findings
Between Oct 18, 2012, and Feb 10, 2014, we recruited 1269 eligible participants (two participants were randomly assigned but not eligible and therefore excluded) and 1040 (82%) consented to be approached about additional follow-up and to have their medical notes reviewed at 5 years. The primary outcome (weight) was ascertained for 871 (69%) of 1267 eligible participants. Mean duration of follow-up was 5·1 (SD 0·3) years. Mean weight change from baseline to 5 years was −0·46 (SD 8·31) kg in the brief intervention group, −1·95 (9·55) kg in the 12-week programme group, and −2·67 (9·81) kg in the 52-week programme. The adjusted difference in weight change was –1·76 (95% CI –3·68 to 0·17) kg between the 52-week programme and the brief intervention; –0·80 (–2·13 to 0·54) kg between the 52-week and the 12-week programme; and –0·96 (–2·90 to 0·97) kg between the 12-week programme and the brief intervention. During the trial, the 12-week programme incurred the lowest cost and produced the highest quality-adjusted life-years (QALY). Simulations beyond 5 years suggested that the 52-week programme would deliver the highest QALYs at the lowest cost and would be the most cost-effective. No participants reported adverse events related to the intervention.
Interpretation
Although the difference in weight change between groups was not statistically significant, some weight loss was maintained at 5 years after an open-group behavioural weight management programme. Health economic modelling suggests that this could have important implications to reduce the incidence of weight-related disease and these interventions might be cost-saving.
Funding
The UK National Institute for Health and Care Research Programme Grants for Applied Research and the Medical Research Council
Attachment goes to court: child protection and custody issues
Attachment theory and research are drawn upon in many applied settings, including family courts, but misunderstandings are widespread and sometimes result in misapplications. The aim of this consensus statement is, therefore, to enhance understanding, counter misinformation, and steer family-court utilisation of attachment theory in a supportive, evidence-based direction, especially with regard to child protection and child custody decision-making. The article is divided into two parts. In the first, we address problems related to the use of attachment theory and research in family courts, and discuss reasons for these problems. To this end, we examine family court applications of attachment theory in the current context of the best-interest-of-the-child standard, discuss misunderstandings regarding attachment theory, and identify factors that have hindered accurate implementation. In the second part, we provide recommendations for the application of attachment theory and research. To this end, we set out three attachment principles: the child’s need for familiar, non-abusive caregivers; the value of continuity of good-enough care; and the benefits of networks of attachment relationships. We also discuss the suitability of assessments of attachment quality and caregiving behaviour to inform family court decision-making. We conclude that assessments of caregiver behaviour should take center stage. Although there is dissensus among us regarding the use of assessments of attachment quality to inform child custody and child-protection decisions, such assessments are currently most suitable for targeting and directing supportive interventions. Finally, we provide directions to guide future interdisciplinary research collaboration
El Apego Va a Juicio: Problemas de Custodia y Protección Infantil1
Attachment theory and research are drawn upon in many applied settings, including family courts, but misunderstandings are widespread and sometimes result in misapplications. The aim of this consensus statement is, therefore, to enhance understanding, counter misinformation, and steer family-court utilisation of attachment theory in a supportive, evidence-based direction, especially with regard to child protection and child custody decision-making. This article is divided into two parts. In the first part, we address problems related to the use of attachment theory and research in family courts, and discuss reasons for these problems. To this end, we examine family court applications of attachment theory in the current context of the best-interest-of-the-child standard, discuss misunderstandings regarding attachment theory, and identify factors that have hindered accurate implementation. In the second part, we provide recommendations for the application of attachment theory and research. To this end, we set out three attachment principles: the child’s need for familiar, non-abusive caregivers; the value of continuity of good-enough care; and the benefits of networks of attachment relationships. We also discuss the suitability of assessments of attachment quality and caregiving behaviour to inform family court decision-making. We conclude that assessments of caregiver behaviour should take center stage. Although there is dissensus among us regarding the use of assessments of attachment quality to inform child custody and child-protection decisions, such assessments are currently most suitable for targeting and directing supportive interventions. Finally, we provide directions to guide future interdisciplinary research collaboration
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