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Tribology—the study of contacting, sliding surfaces—seeks to explain the fundamental mechanisms underlying friction, adhesion, lubrication, and wear, and to apply this knowledge to technologies ranging from transportation and manufacturing to biomedicine and energy. Investigating the contact and sliding of materials is complicated by the fact that the interface is buried from view, inaccessible to conventional experimental tools. In situ investigations are thus critical in visualizing and identifying the underlying physical processes. This article presents key recent advances in the understanding of tribological phenomena made possible by in situ experiments at the nanoscale. Specifically, progress in three key areas is highlighted: (1) direct observation of physical processes in the sliding contact; (2) quantitative analysis of the synergistic action of sliding and chemical reactions (known as tribochemistry) that drives material removal; and (3) understanding the surface and subsurface deformations occurring during sliding of metals. The article also outlines emerging areas where in situ nanoscale investigations can answer critical tribological questions in the future.
In his seminal work on Sidon sets, Pisier found an important characterization of Sidonicity: A set is Sidon if and only if it is proportionally quasi-independent. Later, it was shown that Sidon sets were proportionally “special” Sidon in several other ways. Here, we prove that Sidon sets in torsion-free groups are proportionally
-degree independent, a higher order of independence than quasi-independence, and we use this to prove that Sidon sets are proportionally Sidon with Sidon constants arbitrarily close to one, the minimum possible value.
A growing population of adults living with severe, chronic childhood-onset health conditions has created a need for specialized health care delivered by providers who have expertise both in adult medicine and in those conditions. Optimal care of these patients requires systematic approaches to healthcare transition (HCT). Guidelines for HCT exist, but gaps in care occur, and there are limited data on outcomes of HCT processes.
The Single Disease Workgroup of the Lifespan Domain Task Force of the National Center for Advancing Translational Sciences Clinical and Translational Science Award programs convened a group to review the current state of HCT and to identify gaps in research and practice. Using cystic fibrosis and sickle cell disease as models, key themes were developed. A literature search identified general and disease-specific articles. We summarized key findings.
We identified literature characterizing patient, parent and healthcare provider perspectives, recommendations for transition care, and barriers to effective transition.
With increased survival of patients with severe childhood onset diseases, ongoing study of effective transition practices is essential as survival increases for severe childhood onset diseases. We propose pragmatic methods to enhance transition research to improve health and key outcomes.
In a ‘post-truth’ era in which personality and opinion trump evidence and reason, the need for frankness in debates about the use and boundaries of science and policy is high. We welcome the reflective and nuanced approach to behavioural science in policy-making in Sanders, Snijders and Hallsworth's (2018) piece. Despite our support for the approach in this paper, we suggest that there are deeper issues than are currently acknowledged. Our critique tackles three issues: the empirical, the normative and the political. In the first section, we examine what counts as ‘behavioural’ and how this label is used to legitimate a range of policy activities. We then look at randomised controlled trials in the next section, highlighting the extra-scientific dimensions of the empirical ‘What Works’ revolution. Finally, we question some ontological assumptions that drive empirical research and its translation into policy, asking where the collective is to be found in behavioural public policy.
In September 2016, the annual meeting of the International Union for Quaternary Research’s Loess and Pedostratigraphy Focus Group, traditionally referred to as a LoessFest, met in Eau Claire, Wisconsin, USA. The 2016 LoessFest focused on “thin” loess deposits and loess transportation surfaces. This LoessFest included 75 registered participants from 10 countries. Almost half of the participants were from outside the United States, and 18 of the participants were students. This review is the introduction to the special issue for Quaternary Research that originated from presentations and discussions at the 2016 LoessFest. This introduction highlights current understanding and ongoing work on loess in various regions of the world and provides brief summaries of some of the current approaches/strategies used to study loess deposits.
Introduction: Because of financial pressures, low-income individuals sometimes run out of cellphone service towards the end of the month.
Aims: To determine if the time of month affects ability to reach low-income smokers by telephone.
Methods: We reviewed data from a completed trial in the United States of emergency department (ED)-initiated tobacco dependence treatment for low-income smokers at a busy, academic ED in an urban community. We recorded the date of each one-month follow-up call, and divided each month into four time blocks: Week 1, Week 2, Week 3, and Week 4.
Results: A total of 2,049 phone calls were made to reach 769 participants. Of these calls, 677 (33%) resulted in contact; 88% of all participants were contacted. Using generalised estimating equations with Week 4 as reference, the odds of a successful contact at Weeks 1, 2, and 3 were, respectively, 1.52 (95% CI 1.18, 1.96), 1.30 (95% CI 1.01, 1.66), and 1.37 (95% CI 1.07, 1.76).
Conclusions: Study participants became progressively difficult to reach. This result may reflect low-income smokers’ decreased rates of active telephone service later in the month and suggests a mechanism to improve follow-up rates in future studies of low-income populations.
Anxiety disorders are common, and cognitive–behavioural therapy (CBT) is a first-line treatment. Candidate gene studies have suggested a genetic basis to treatment response, but findings have been inconsistent.
To perform the first genome-wide association study (GWAS) of psychological treatment response in children with anxiety disorders (n = 980).
Presence and severity of anxiety was assessed using semi-structured interview at baseline, on completion of treatment (post-treatment), and 3 to 12 months after treatment completion (follow-up). DNA was genotyped using the Illumina Human Core Exome-12v1.0 array. Linear mixed models were used to test associations between genetic variants and response (change in symptom severity) immediately post-treatment and at 6-month follow-up.
No variants passed a genome-wide significance threshold (P=5×10–8) in either analysis. Four variants met criteria for suggestive significance (P<5×10–6) in association with response post-treatment, and three variants in the 6-month follow-up analysis.
This is the first genome-wide therapygenetic study. It suggests no common variants of very high effect underlie response to CBT. Future investigations should maximise power to detect single-variant and polygenic effects by using larger, more homogeneous cohorts.
A fractal geometry of clast size within the test wall in the Antarctic agglutinated foraminifera Hormosina mortenseni Cushman, 1910 and Cyclammina cancellata Brady, 1879 has been identified with the use of Scanning Electron Microscopic techniques. External surface and internal clast distributions in H. mortenseni display a self-similar distribution. C. cancellata has an internal self-similar grain arrangement, whereas the exterior surface shows an alternative grain distribution. Power law relationships between particle density and grain diameter enable values of fractal dimension (D) to be calculated; these “D-values” represent the absolute gradient of the power law relationship. The dimensions acquired from the foraminiferal study correspond well with those previously obtained from natural fractal geological structures and ideal fractals. The self-similar grain arrangement within walls of the foraminifera exists over three orders of magnitude, after which alternative methods of test wall construction are evident. This suggests that a limit exists where grain selection terminates. A self-similar grain distribution limits the amount of biologically produced adhesive material required by the foraminifera for constructing their tests.
Emerging research indicates the critical role members of the public can play in saving lives and reducing morbidity at the scene in the immediate aftermath of a disaster. It is anticipated that with training, more members of the public will be ready and able to assist should they be present at mass casualty events or other circumstances in which there are serious injuries or potential loss of life. This article describes a training course developed by multiple federal and nonfederal partners aimed at preparing the public to become “active bystanders” followed by a pilot demonstration project conducted by Medical Reserve Corps Units. The outcomes of the project indicated that the training was comprehensive and appropriate for members of the public with little or no first aid knowledge. National availability of the “Becoming an Active Bystander” training course is currently being planned. (Disaster Med Public Health Preparedness. 2016;10:286–292).
We previously reported an association between 5HTTLPR genotype and
outcome following cognitive–behavioural therapy (CBT) in child anxiety
(Cohort 1). Children homozygous for the low-expression short-allele
showed more positive outcomes. Other similar studies have produced mixed
results, with most reporting no association between genotype and CBT
To replicate the association between 5HTTLPR and CBT outcome in child
anxiety from the Genes for Treatment study (GxT Cohort 2,
n = 829).
Logistic and linear mixed effects models were used to examine the
relationship between 5HTTLPR and CBT outcomes. Mega-analyses using both
cohorts were performed.
There was no significant effect of 5HTTLPR on CBT outcomes in Cohort 2.
Mega-analyses identified a significant association between 5HTTLPR and
remission from all anxiety disorders at follow-up (odds ratio 0.45,
P = 0.014), but not primary anxiety disorder
The association between 5HTTLPR genotype and CBT outcome did not
replicate. Short-allele homozygotes showed more positive treatment
outcomes, but with small, non-significant effects. Future studies would
benefit from utilising whole genome approaches and large, homogenous
Understanding the origin of modern communities is a fundamental goal of ecology, but reconstructing communities with durations of 103–106 years requires data from the fossil record. Early Pliocene to latest Pleistocene faunas and sediments in the Meade Basin and modern soils and rodents from the same area are used to examine the role of environmental change in the emergence of the modern community. Paleoenvironmental proxies measured on modern surface soils and paleosols are described, and faunal dynamics of fossil rodents are discussed. Mean annual precipitation (MAP) was estimated from elemental concentrations and magnetic properties, and warm-season temperature and δ18O of soil water was estimated using carbonate isotope paleothermometry on pedogenic nodules. MAP and temperature estimates from paleosols exhibit no short-term variability, no long-term trends, and generally bracket modern values. Estimated soil water δ18O values increased through time, suggesting aridification played a role in the evolution of the regional grassland ecosystem. Carbon isotope analyses of biomarkers are used to examine the abundance of C4 grasses, which suggest more C4 biomass and more variability in C4 biomass than carbonate proxies. Rodent species richness remained constant due to balanced rates of extinction and immigration, both of which show episodic spikes consistent with a balance between forcing mechanisms that result in equilibrium on long time scales. Overall, these results suggest that different mechanisms of faunal change may be acting at different time scales, although the stratigraphic resolution of paleoenvironmental proxies needs to be increased, and body size and dietary distributions of rodents need to be determined before which processes of change are most important can be decided.
Although beta-amyloid, anxiety and depression have been linked cross-sectionally to reduced memory function in healthy older adults without dementia, prospective data evaluating these associations are lacking. Using data from an observational cohort study of 178 healthy older adults without dementia followed for 3 years, we found that anxiety symptoms significantly moderated the relationship between beta-amyloid level and decline in verbal (Cohen's d = 0.65) and episodic (Cohen's d = 0.38) memory. Anxiety symptoms were additionally linked to greater decline in executive function, irrespective of beta-amyloid and other risk factors. These findings suggest that interventions to mitigate anxiety symptoms may help delay memory decline in otherwise healthy older adults with elevated beta-amyloid.
Background: A randomized controlled trial has shown that supervised, facility-based exercise training is effective in improving glycemic control in type 2 diabetes. However, these programs are associated with additional costs. This analysis assessed the cost-effectiveness of such programs.
Methods: Analysis used data from the Diabetes Aerobic and Resistance Exercise (DARE) clinical trial which compared three different exercise programs (resistance, aerobic or a combination of both) of 6 months duration with a control group (no exercise program). Clinical outcomes at 6 months were entered for individual patients into the UKPDS economic model for type 2 diabetes adapted for the Canadian context. From this, expected life-years, quality-adjusted life-years (QALYs) and costs were estimated for all patients within the trial.
Results: The combined exercise program was the most expensive ($40,050) followed by the aerobic program ($39,250), the resistance program ($38,300) and no program ($31,075). QALYs were highest for combined (8.94), followed by aerobic (8.77), resistance (8.73) and no program (8.70). The incremental cost per QALY gained for the combined exercise program was $4,792 compared with aerobic alone, $8,570 compared with resistance alone, and $37,872 compared with no program. The combined exercise program remained cost-effective for all scenarios considered within sensitivity analysis.
Conclusions: A program providing training in both resistance and aerobic exercise was the most cost-effective of the alternatives compared. Based on previous funding decisions, exercise training for individuals with diabetes can be considered an efficient use of resources.
While distal sensory polyneuropathy (DSP) is the most common neurological condition associated with HIV, causing nerve damage in upper and lower extremities, its impact on neuropsychological test performance is unclear. In this study, we analyzed baseline data for 278 HIV-infected participants with comprehensive neurological and neurocognitive evaluations to examine the contribution of DSP and anatomic distribution of neuropathic signs (upper extremity or lower extremity) on standardized domain scores. We found that participants with DSP performed significantly worse in multiple domains containing timed psychomotor tests (i.e., motor, information processing speed and executive functioning). With regard to executive functioning, differences were limited to a test with a motor component (Trail Making Test, Part B). The group with clinically detectable neuropathic signs in the upper extremities and the group with signs limited to the lower extremities both performed worse in the motor domain than the group without DSP. Participants with DSP demonstrated a unique pattern of impairment limited to neuropsychological domains with timed psychomotor tests. These results suggest that caution should be used in interpretation of neuropsychological tests in patients with DSP, as some abnormalities may be exacerbated by peripheral nervous system pathology. (JINS, 2012, 19, 1–10)