Charge Conjugation from Space-Time Inversion

We show that the CPT group of the Dirac field emerges naturally from the PT and P (or T) subgroups of the Lorentz group.Comment: 4 pages, no figure

Chlamydia trachomatis from Australian Aboriginal people with trachoma are polyphyletic composed of multiple distinctive lineages.

Chlamydia trachomatis causes sexually transmitted infections and the blinding disease trachoma. Current data on C. trachomatis phylogeny show that there is only a single trachoma-causing clade, which is distinct from the lineages causing urogenital tract (UGT) and lymphogranuloma venerum diseases. Here we report the whole-genome sequences of ocular C. trachomatis isolates obtained from young children with clinical signs of trachoma in a trachoma endemic region of northern Australia. The isolates form two lineages that fall outside the classical trachoma lineage, instead being placed within UGT clades of the C. trachomatis phylogenetic tree. The Australian trachoma isolates appear to be recombinants with UGT C. trachomatis genome backbones, in which loci that encode immunodominant surface proteins (ompA and pmpEFGH) have been replaced by those characteristic of classical ocular isolates. This suggests that ocular tropism and association with trachoma are functionally associated with some sequence variants of ompA and pmpEFGH

Study protocol of cost-effectiveness and cost-utility of a biopsychosocial multidisciplinary intervention in the evolution of non-specific sub-acute low back pain in the working population: cluster randomised trial.

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Background: Low back pain (LBP), with high incidence and prevalence rate, is one of the most common reasons to consult the health system and is responsible for a significant amount of sick leave, leading to high health and social costs. The objective of the study is to assess the cost-effectiveness and cost-utility analysis of a multidisciplinary biopsychosocial educational group intervention (MBEGI) of non-specific sub-acute LBP in comparison with the usual care in the working population recruited in primary healthcare centres. Methods/design: The study design is a cost-effectiveness and cost-utility analysis of a MBEGI in comparison with the usual care of non-specific sub-acute LBP.Measures on effectiveness and costs of both interventions will be obtained from a cluster randomised controlled clinical trial carried out in 38 Catalan primary health care centres, enrolling 932 patients between 18 and 65 years old with a diagnosis of non-specific sub-acute LBP. Effectiveness measures are: pharmaceutical treatments, work sick leave (% and duration in days), Roland Morris disability, McGill pain intensity, Fear Avoidance Beliefs (FAB) and Golberg Questionnaires. Utility measures will be calculated from the SF-12. The analysis will be performed from a social perspective. The temporal horizon is at 3 months (change to chronic LBP) and 12 months (evaluate the outcomes at long term. Assessment of outcomes will be blinded and will follow the intention-to-treat principle. Discussion: We hope to demonstrate the cost-effectiveness and cost-utility of MBEGI, see an improvement in the patients' quality of life, achieve a reduction in the duration of episodes and the chronicity of non-specific low back pain, and be able to report a decrease in the social costs. If the intervention is cost-effectiveness and cost-utility, it could be applied to Primary Health Care Centres. Trial registration: ISRCTN: ISRCTN5871969

Coupled free-carrier and exciton relaxation in optically excited semiconductors

The energy relaxation of coupled free-carrier and exciton populations in semiconductors after low-density ultrafast optical excitation is studied through a kinetic approach. The set of semiclassical Boltzmann equations, usually written for electron and hole populations only, is complemented by an additional equation for the exciton distribution. The equations are coupled by reaction terms describing phonon-mediated exciton binding and dissociation. All the other relevant scattering mechanisms, such as carrier-carrier, carrier-phonon, and exciton-phonon interactions, are also included. The resulting system of rate equations in reciprocal space is solved by an extended ensemble Monte Carlo method. As a first application, we show results for the dynamics of bulk GaAs in the range from 1 to ∼200 ps after photoexcitation. The build-up of an exciton population and its sensitivity to the excitation conditions are discussed in detail. As a consequence of the pronounced energy dependence of the LO-phonon-assisted transition probabilities between free-pair states and excitons, it is found that the efficiency of the exciton-formation process and the temporal evolution of the resulting population are sensitive to the excitation energy. We discuss the effects on luminescence experiments

New Species in the Old World: Europe as a Frontier in Biodiversity Exploration, a Test Bed for 21st Century Taxonomy

The number of described species on the planet is about 1.9 million, with ca. 17,000 new species described annually, mostly from the tropics. However, taxonomy is usually described as a science in crisis, lacking manpower and funding, a politically acknowledged problem known as the Taxonomic Impediment. Using data from the Fauna Europaea database and the Zoological Record, we show that contrary to general belief, developed and heavily-studied parts of the world are important reservoirs of unknown species. In Europe, new species of multicellular terrestrial and freshwater animals are being discovered and named at an unprecedented rate: since the 1950s, more than 770 new species are on average described each year from Europe, which add to the 125,000 terrestrial and freshwater multicellular species already known in this region. There is no sign of having reached a plateau that would allow for the assessment of the magnitude of European biodiversity. More remarkably, over 60% of these new species are described by non-professional taxonomists. Amateurs are recognized as an essential part of the workforce in ecology and astronomy, but the magnitude of non-professional taxonomist contributions to alpha-taxonomy has not been fully realized until now. Our results stress the importance of developing a system that better supports and guides this formidable workforce, as we seek to overcome the Taxonomic Impediment and speed up the process of describing the planetary biodiversity before it is too late

Assessment of Association of Increased Heart Rates to Cardiovascular Events among Healthy Subjects in the United States: Analysis of a Primary Care Electronic Medical Records Database

Objective. To determine whether increases in heart rates (HRs) over time leads to adverse cardiovascular (CV) events among “healthy subjects.” Methods. This retrospective cohort study used the GE Centricity EMR database. “Healthy subjects” were defined as those with Charlson Comorbidity Index (CCI) score = 0 and Chronic Disease Score (CDS) = 0 at baseline. Subjects were followed for 3 years post the first date of a clinical encounter between the patient and provider. Those aged ≥18 years old with baseline HR and ≥2 post-index HR readings were identified between 01/01/1996 to 03/30/2007. Results. There were 93,952 “healthy subjects” at baseline (median age 42 years; 67.2% women; mean HR was 75.8 (SD: 11) bpm); 20.7% with a mean HR at baseline of 76.3 (SD: 11.3) bpm (median age 45; 63 women) experienced a CV event during 3 years of follow-up. The mean HR was higher among those with a CV event (76.3 bmp) compared to those without a CV event (75.7 bpm). A Cox regression model indicated that an increase in HR by 5 bpm was associated with a 1% increase in CV event risk. Conclusions. Elevated HRs are associated with an increased likelihood of CV events among “healthy subjects”

Learning a reactive potential for silica-water through uncertainty attribution

The reactivity of silicates in an aqueous solution is relevant to various chemistries ranging from silicate minerals in geology, to the C-S-H phase in cement, nanoporous zeolite catalysts, or highly porous precipitated silica. While simulations of chemical reactions can provide insight at the molecular level, balancing accuracy and scale in reactive simulations in the condensed phase is a challenge. Here, we demonstrate how a machine-learning reactive interatomic potential can accurately capture silicate-water reactivity. The model was trained on a new dataset comprising 400,000 energies and forces of molecular clusters at the $\omega$-B97XD def2-TVZP level. To ensure the robustness of the model, we introduce a new and general active learning strategy based on the attribution of the model uncertainty, that automatically isolates uncertain regions of bulk simulations to be calculated as small-sized clusters. Our trained potential is found to reproduce static and dynamic properties of liquid water and solid crystalline silicates, despite having been trained exclusively on cluster data. Furthermore, we utilize enhanced sampling simulations to recover the self-ionization reactivity of water accurately, and the acidity of silicate oligomers, and lastly study the silicate dimerization reaction in a water solution at neutral conditions and find that the reaction occurs through a flanking mechanism.Comment: 26 pages, 4 figures, 1 supplementary figur

Investigating the formation of giant {Pd72}Prop and {Pd84}Gly macrocycles using NMR, HPLC and mass spectrometry

The formation of giant polyoxometalate (POM) species are relatively underexplored as their self-assembly process is complex due to the rapid kinetics. Polyoxopalladates (POPds) are a class of POMs based on Pd, the largest of which is the {Pd84}Ac wheel, and the slower kinetics mean the system is more amenable to systematic study. Here, we show it is possible to follow the assembly of two types of Pd-wheel; the {Pd84}Gly the smaller {Pd72}Prop wheel formed using glycolate and propionate ligands respectively. We analyzed the formation of {Pd72}Prop and {Pd84}Gly using mass spec-trometry (SEC-HPLC-MS and preparative desalting followed by MS). This was accompanied by studies that followed the chemical shift differences between the outer/inner ligands and the free ligand in solution for the {Pd84}Ac, {Pd72}Prop, and {Pd84}Gly species using NMR; this showed it was possible to track the formation of the wheels. Our findings confirm that the macrocycles assemble from smaller building blocks which react together to form the larger species over a period of days. These findings open the way for further structural derivatives and exploration of their host-guest chemistry

Cost-effectiveness of Physical Therapy vs Intra-articular Glucocorticoid Injection for Knee Osteoarthritis: A Secondary Analysis From a Randomized Clinical Trial

Importance: Physical therapy and glucocorticoid injections are initial treatment options for knee osteoarthritis, but available data indicate that most patients receive one or the other, suggesting they may be competing interventions. The initial cost difference for treatment can be substantial, with physical therapy often being more expensive at the outset, and cost-effectiveness analysis can aid patients and clinicians in making decisions. Objective: To investigate the incremental cost-effectiveness between physical therapy and intra-articular glucocorticoid injection as initial treatment strategies for knee osteoarthritis. Design, setting, and participants: This economic evaluation is a secondary analysis of a randomized clinical trial performed from October 1, 2012, to May 4, 2017. Health economists were blinded to study outcomes and treatment allocation. A randomized sample of patients seen in primary care and physical therapy clinics with a radiographically confirmed diagnosis of knee osteoarthritis were evaluated from the clinical trial with 96.2% follow-up at 1 year. Interventions: Physical therapy or glucocorticoid injection. Main outcomes and measures: The main outcome was incremental cost-effectiveness between 2 alternative treatments. Acceptability curves of bootstrapped incremental cost-effectiveness ratios (ICERs) were used to identify the proportion of ICERs under the specific willingness-to-pay level ($50 000-$100 000). Health care system costs (total and knee related) and health-related quality-of-life based on quality-adjusted life-years (QALYs) were obtained. Results: A total of 156 participants (mean [SD] age, 56.1 [8.7] years; 81 [51.9%] male) were randomized 1:1 and followed up for 1 year. Mean (SD) 1-year knee-related medical costs were $2113 ($4224) in the glucocorticoid injection group and $2131 ($1015) in the physical therapy group. The mean difference in QALY significantly favored physical therapy at 1 year (0.076; 95% CI, 0.02-0.126; P = .003). Physical therapy was the more cost-effective intervention, with an ICER of $8103 for knee-related medical costs, with a 99.2$100 000. Conclusions and relevance: A course of physical therapy was cost-effective compared with a course of glucocorticoid injections for patients with knee osteoarthritis. These results suggest that, although the initial cost of delivering physical therapy may be higher than an initial course of glucocorticoid injections, 1-year total knee-related costs are equivalent, and greater improvement in QALYs may justify the initial higher costs. Trial registration: ClinicalTrials.gov Identifier: NCT0142715

Seafood prices reveal impacts of a major ecological disturbance

Coastal hypoxia (dissolved oxygen ≤ 2 mg/L) is a growing problem worldwide that threatens marine ecosystem services, but little is known about economic effects on fisheries. Here, we provide evidence that hypoxia causes economic impacts on a major fishery. Ecological studies of hypoxia and marine fauna suggest multiple mechanisms through which hypoxia can skew a population’s size distribution toward smaller individuals. These mechanisms produce sharp predictions about changes in seafood markets. Hypoxia is hypothesized to decrease the quantity of large shrimp relative to small shrimp and increase the price of large shrimp relative to small shrimp. We test these hypotheses using time series of size-based prices. Naive quantity-based models using treatment/control comparisons in hypoxic and nonhypoxic areas produce null results, but we find strong evidence of the hypothesized effects in the relative prices: Hypoxia increases the relative price of large shrimp compared with small shrimp. The effects of fuel prices provide supporting evidence. Empirical models of fishing effort and bioeconomic simulations explain why quantifying effects of hypoxia on fisheries using quantity data has been inconclusive. Specifically, spatial-dynamic feedbacks across the natural system (the fish stock) and human system (the mobile fishing fleet) confound “treated” and “control” areas. Consequently, analyses of price data, which rely on a market counterfactual, are able to reveal effects of the ecological disturbance that are obscured in quantity data. Our results are an important step toward quantifying the economic value of reduced upstream nutrient loading in the Mississippi Basin and are broadly applicable to other coupled human-natural systems.publishedVersio