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Compound-specific radiocarbon (14C) dating often requires working with small samples of < 100 µg carbon (µgC). This makes the radiocarbon dates of biomarker compounds very sensitive to biases caused by extraneous carbon of unknown composition, a procedural blank, which is introduced to the samples during the steps necessary to prepare a sample for radiocarbon analysis by accelerator mass spectrometry (i.e., isolating single compounds from a heterogeneous mixture, combustion, gas purification and graphitization). Reporting accurate radiocarbon dates thus requires a correction for the procedural blank. We present our approach to assess the fraction modern carbon (F14C) and the mass of the procedural blanks introduced during the preparation procedures of lipid biomarkers (i.e. n-alkanoic acids) and lignin phenols. We isolated differently sized aliquots (6–151 µgC) of n-alkanoic acids and lignin phenols obtained from standard materials with known F14C values. Each compound class was extracted from two standard materials (one fossil, one modern) and purified using the same procedures as for natural samples of unknown F14C. There is an inverse linear relationship between the measured F14C values of the processed aliquots and their mass, which suggests constant contamination during processing of individual samples. We use Bayesian methods to fit linear regression lines between F14C and 1/mass for the fossil and modern standards. The intersection points of these lines are used to infer F14Cblank and mblank and their associated uncertainties. We estimate 4.88 ± 0.69 μgC of procedural blank with F14C of 0.714 ± 0.077 for n-alkanoic acids, and 0.90 ± 0.23 μgC of procedural blank with F14C of 0.813 ± 0.155 for lignin phenols. These F14Cblank and mblank can be used to correct AMS results of lipid and lignin samples by isotopic mass balance. This method may serve as a standardized procedure for blank assessment in small-scale radiocarbon analysis.
Timely access to care services is crucial to support people with dementia and their family carers to live well. Carers of people with dementia (N = 390), recruited from eight countries, completed semi-structured interviews about their experiences of either accessing or not using formal care services over a 12-month period in the Access to Timely Formal Care (Actifcare) study. Participant responses were summarised using content analysis, categorised into clusters and frequencies were calculated. Less than half of the participants (42.3%) reported service use. Of those using services, 72.8 per cent reported timely access and of those not using services 67.2 per cent were satisfied with this situation. However, substantial minorities either reported access at the wrong time (27.2%), or feeling dissatisfied or mixed feelings about not accessing services (32.8%). Reasons for not using services included use not necessary yet, the carer provided support or refusal. Reasons given for using services included changes in the condition of the person with dementia, the service's ability to meet individual needs, not coping or the opportunity to access services arose. Facilitators and barriers to service use included whether participants experienced supportive professionals, the speed of the process, whether the general practitioner was helpful, participant's own proactive attitude and the quality of information received. To achieve timely support, simplified pathways to use of formal care services are needed.
The estimation of origination and extinction rates and their temporal variation is central to understanding diversity patterns and the evolutionary history of clades. The fossil record provides the only direct evidence of extinction and biodiversity changes through time and has long been used to infer the dynamics of diversity changes in deep time. The software PyRate implements a Bayesian framework to analyze fossil occurrence data to estimate the rates of preservation, origination, and extinction while incorporating several sources of uncertainty. Building upon this framework, we present a suite of methodological advances including more complex and realistic models of preservation and the first likelihood-based test to compare the fit across different models. Further, we develop a new reversible jump Markov chain Monte Carlo algorithm to estimate origination and extinction rates and their temporal variation, which provides more reliable results and includes an explicit estimation of the number and temporal placement of statistically significant rate changes. Finally, we implement a new C++ library that speeds up the analyses by orders of magnitude, therefore facilitating the application of the PyRate methods to large data sets. We demonstrate the new functionalities through extensive simulations and with the analysis of a large data set of Cenozoic marine mammals. We compare our analytical framework against two widely used alternative methods to infer origination and extinction rates, revealing that PyRate decisively outperforms them across a range of simulated data sets. Our analyses indicate that explicit statistical model testing, which is often neglected in fossil-based macroevolutionary analyses, is crucial to obtain accurate and robust results.
Little is known about the effect of natural disasters on children's neural development. Additionally, despite evidence that stress and parenting may both influence the development of neural systems underlying reward and threat processing, few studies have brought together these areas of research. The current investigation examined the effect of parenting styles and hurricane-related stress on the development of neural reactivity to reward and threat in children. Approximately 8 months before and 9 months after Hurricane Sandy, 74 children experiencing high and low levels of hurricane-related stress completed tasks that elicited the reward positivity and error-related negativity, event-related potentials indexing sensitivity to reward and threat, respectively. At the post-Hurricane assessment, children completed a self-report questionnaire to measure promotion- and prevention-focused parenting styles. Among children exposed to high levels of hurricane-related stress, lower levels of promotion-focused, but not prevention-focused, parenting were associated with a reduced post-Sandy reward positivity. In addition, in children with high stress exposure, greater prevention-focused, but not promotion-focused, parenting was associated with a larger error-related negativity after Hurricane Sandy. These findings highlight the need to consider contextual variables such as parenting when examining how exposure to stress alters the development of neural reactivity to reward and threat in children.
Patients with Parkinson’s disease psychosis (PDP) are often treated with an atypical antipsychotic, especially quetiapine or clozapine, but side effects, lack of sufficient efficacy, or both may motivate a switch to pimavanserin, the first medication approved for management of PDP. How best to implement a switch to pimavanserin has not been clear, as there are no controlled trials or case series in the literature to provide guidance. An abrupt switch may interrupt partially effective treatment or potentially trigger rebound effects from antipsychotic withdrawal, whereas cross-taper involves potential drug interactions. A panel of experts drew from published data, their experience treating PDP, lessons from switching antipsychotic drugs in other populations, and the pharmacology of the relevant drugs, to establish consensus recommendations. The panel concluded that patients with PDP can be safely and effectively switched from atypical antipsychotics used off label in PDP to the recently approved pimavanserin by considering each agent’s pharmacokinetics and pharmacodynamics, receptor interactions, and the clinical reason for switching (efficacy or adverse events). Final recommendations are that such a switch should aim to maintain adequate 5-HT2A antagonism during the switch, thus providing a stable transition so that efficacy is maintained. Specifically, the consensus recommendation is to add pimavanserin at the full recommended daily dose (34 mg) for 2–6 weeks in most patients before beginning to taper and discontinue quetiapine or clozapine over several days to weeks. Further details are provided for this recommendation, as well as for special clinical circumstances where switching may need to proceed more rapidly.
Numerous studies have demonstrated that genetic and environmental factors interact to influence alcohol problems. Yet prior research has primarily focused on samples of European descent and little is known about gene–environment interactions in relation to alcohol problems in non-European populations. In this study, we examined whether and how genetic risk for alcohol problems and peer deviance and interpersonal traumatic events independently and interactively influence trajectories of alcohol use disorder symptoms in a sample of African American students across the college years (N = 1,119; Mage = 18.44 years). Data were drawn from the Spit for Science study where participants completed multiple online surveys throughout college and provided a saliva sample for genotyping. Multilevel growth curve analyses indicated that alcohol dependence genome-wide polygenic risk scores did not predict trajectory of alcohol use disorder symptoms, while family history of alcohol problems was associated with alcohol use disorder symptoms at the start of college but not with the rate of change in symptoms over time. Peer deviance and interpersonal traumatic events were associated with more alcohol use disorder symptoms across college years. Neither alcohol dependence genome-wide polygenic risk scores nor family history of alcohol problems moderated the effects of these environmental risk factors on alcohol use disorder symptoms. Our findings indicated that peer deviance and experience of interpersonal traumatic events are salient risk factors that elevate risk for alcohol problems among African American college students. Family history of alcohol problems could be a useful indicator of genetic risk for alcohol problems. Gene identification efforts with much larger samples of African descent are needed to better characterize genetic risk for alcohol use disorders, in order to better understand gene–environment interaction processes in this understudied population.
Several reports have shown that doctoral and postdoctoral trainees in biomedical research pursue diverse careers that advance science meaningful to society. Several groups have proposed 3-tier career taxonomy to showcase these outcomes. This 3-tier taxonomy will be a valuable resource for institutions committed to greater transparency in reporting outcomes, to not only be transparent in reporting their own institutional data but also to lend greater power to a central repository.
The socioeconomic burden of diseases is increasing in Africa. For instance in 2011, 70 percent of the world's human immunodeficiency virus (HIV) population resided in sub-Sahara Africa. There are also growing rates of Antimicrobial Resistance (AMR), which necessitates newer more expensive antibiotics adding to costs. There is also a growing burden of non-communicable diseases (NCDs), three out of four patients with hypertension currently live in low and middle income countries (LMICs), with prevalence rates up to 30 to 45 percent among adults in Africa. Alongside this, up to 70 percent of total healthcare expenditure is spent on medicines in LMICs; much of this out-of-pocket. Consequently, there is an urgent need to strengthen collaborative research to improve medicine use.
Summary of groups working together in Africa including the Medicines Utilisation Research in Africa (MURIA) group.
African Strategies for Health identifies and advocates best practices, as well as works with others to develop sustainable solutions. Pharmacology for Africa (PharfA) organises and promotes pharmacology on the African continent, including research in clinical pharmacology, alongside the International Union of Basic and Clinical Pharmacology (IUPHAR) sub-division. International Society for Pharmacoeconomics and Outcomes Research (ISPOR) Africa co-ordinates activities from the different African country chapters. The South African Health Technology Assessment Society (SAHTAS) is a scientific and professional society for all those who produce, use, or encounter Health Technology Assessment (HTA) in Southern Africa, and the World Health Organization (WHO) International and Regional groups are improving antibiotic drug utilization capabilities in Africa. The MURIA group was established in 2015 (1). Ongoing collaborative research includes (i) initiatives to optimize antibiotic use; (ii) methods to enhance adherence to anti-infective prescribing guidance, (iii) approaches to improve adherence to HIV and NCDs; (iv) researching current anti-hypertensive utilization patterns and knowledge; (v) approaches to enhance Drugs and Therapeutic Committees (DTC) activities, and (vi) strengthening medicine utilization capabilities (2,3). These activities have already strengthened research ties across Africa.
A number of groups are already working across Africa to enhance appropriate medicine use, and should continue. Ongoing MURIA activities include antibiotic point-prevalence studies, ongoing research into infectious diseases, NCDs and DTCs including adherence as well as the third workshop and symposium in Namibia in 2017.
Intellectual ability may be an endophenotypic marker for bipolar disorder.
Within a large birth cohort, we aimed to assess whether childhood IQ (including both verbal IQ (VIQ) and performance IQ (PIQ) subscales) was predictive of lifetime features of bipolar disorder assessed in young adulthood.
We used data from the Avon Longitudinal Study of Parents and Children (ALSPAC), a large UK birth cohort, to test for an association between measures of childhood IQ at age 8 years and lifetime manic features assessed at age 22–23 years using the Hypomania Checklist-32 (HCL-32; n=1881 individuals). An ordinary least squares linear regression model was used, with normal childhood IQ (range 90–109) as the referent group. We adjusted analyses for confounding factors, including gender, ethnicity, handedness, maternal social class at recruitment, maternal age, maternal history of depression and maternal education.
There was a positive association between IQ at age 8 years and lifetime manic features at age 22–23 years (Pearson's correlation coefficient 0.159 (95% CI 0.120–0.198), P>0.001). Individuals in the lowest decile of manic features had a mean full-scale IQ (FSIQ) which was almost 10 points lower than those in the highest decile of manic features: mean FSIQ 100.71 (95% CI 98.74–102.6) v. 110.14 (95% CI 107.79–112.50), P>0.001. The association between IQ and manic features was present for FSIQ, VIQ and for PIQ but was strongest for VIQ.
A higher childhood IQ score, and high VIQ in particular, may represent a marker of risk for the later development of bipolar disorder. This finding has implications for understanding of how liability to bipolar disorder may have been selected through generations. It will also inform future genetic studies at the interface of intelligence, creativity and bipolar disorder and is relevant to the developmental trajectory of bipolar disorder. It may also improve approaches to earlier detection and treatment of bipolar disorder in adolescents and young adults.
The error-related negativity (ERN) is a negative deflection in the event-related potential occurring when individuals make mistakes, and is increased in children with internalizing psychopathology. We recently found that harsh parenting predicts a larger ERN in children, and recent work has suggested that variation in the brain-derived neurotrophic factor (BDNF) gene may moderate the impact of early life adversity. Parents and children completed measures of parenting when children were 3 years old (N = 201); 3 years later, the ERN was measured and diagnostic interviews as well as dimensional symptom measures were completed. We found that harsh parenting predicted an increased ERN only among children with a methionine allele of the BDNF genotype, and evidence of moderated mediation: the ERN mediated the relationship between parenting and internalizing diagnoses and dimensional symptoms only if children had a methionine allele. We tested this model with externalizing disorders, and found that harsh parenting predicted externalizing outcomes, but the ERN did not mediate this association. These findings suggest that harsh parenting predicts both externalizing and internalizing outcomes in children; however, this occurs through different pathways that uniquely implicate error-related brain activity in the development of internalizing disorders.
We investigated the frequency and determinants of guideline-discordant antibiotic prescribing in outpatients with respiratory infections or cystitis. Antibiotic prescribing was guideline discordant in 60% of patients. The most common reason for discordance was prescribing an antibiotic when not indicated. In a multivariate analysis, physicians in training had the highest likelihood of guideline-concordant antibiotic prescribing.
In most developed countries, children in lone parent families face a high risk of poverty. A partial solution commonly sought in English-speaking nations is to increase the amounts of private child maintenance paid by the other parent. However, where lone parent families are in receipt of social assistance benefits, some countries hold back a portion of the child maintenance to reduce public expenditures. This partial ‘pass-through’ treats child maintenance as a substitute for cash benefits which conceivably neutralises its poverty reduction potential. Such neutralising effects are not well understood and can be obscured further when more subtle interactions between child maintenance systems and social security systems operate. This research makes a unique contribution to knowledge by exposing the hidden interaction effects operating in similar child maintenance systems across four countries: the United Kingdom, United States (Wisconsin), Australia and New Zealand. We found that when child maintenance is counted as income in calculating benefit entitlements, it can reduce the value of cash benefits. Using model lone parent families with ten different employment and income scenarios, we show how the poverty reduction potential of child maintenance is affected by whether it is treated as a substitute for, or a complement to, cash benefits.
There is increasing interest among developmental psychopathologists in broad transdiagnostic factors that give rise to a wide array of clinical presentations (multifinality), but little is known about how these processes lead to particular psychopathological manifestations over the course of development. We examined whether individual differences in the error-related negativity (ΔERN), a neural indicator of error monitoring, predicts whether early persistent irritability, a prototypical transdiagnostic construct, is associated with later internalizing versus externalizing outcomes. When children were 3 years old, mothers were interviewed about children's persistent irritability and completed questionnaires about their children's psychopathology. Three years later, EEG was recorded while children performed a go/no-go task to measure the ΔERN. When children were approximately 9 years old, mothers again completed questionnaires about their children's psychopathology. The results indicated that among children who were persistently irritable at age 3, an enhanced or more negative ΔERN at age 6 predicted the development of internalizing symptoms at age 9, whereas a blunted or smaller ΔERN at age 6 predicted the development of externalizing symptoms. Our results suggest that variation in error monitoring predicts, and may even shape, the expression of persistent irritability and differentiates developmental trajectories from preschool persistent irritability to internalizing versus externalizing outcomes in middle to late childhood.
In this paper, we prove that if
is a postcritically finite rational map with Julia set homeomorphic to the Sierpiński carpet, then there is an integer
, such that, for any
, there exists an
-invariant Jordan curve
containing the postcritical set of
Johnsongrass populations that are resistant to 5-enolpyruvyl-3-shikimate synthase (EPSPS)–, acetyl coenzyme A carboxylase (ACCase)–, or acetolactate synthase (ALS)–inhibiting herbicides are increasingly common throughout the midsouth. Three trials were conducted in 2012, 2013, and 2014 in Fayetteville, AR and Alexandria, LA to evaluate strategies with and without ALS- and ACCase inhibitors for management of rhizomatous johnsongrass in the absence of glyphosate. Fluometuron or fluometuron plus pyrithiobac applied PRE followed by (fb) EPOST, MPOST, and LAYBY tank mixtures containing multiple effective mechanisms of action (MOA) controlled johnsongrass at least 90%. Simplifying the program by removing a herbicide or eliminating an application timing reduced control, and increased vegetative and sexual reproduction of johnsongrass. To manage severe infestations or escapes glufosinate plus clethodim fb glufosinate plus clethodim or clethodim plus pyrithiobac fb clethodim) effectively controlled 15-cm johnsongrass. However, johnsongrass control was reduced when ALS and ACCase inhibitors were tank mixed, especially for the second POST application, compared to ACCase inhibitors alone. Effective herbicide programs are available to growers to control johnsongrass in the absence of glyphosate, but the use of PRE herbicides followed by multiple applications of POST herbicides is critical for successful management.
Emergency physicians who work in academic settings enjoy an expanding number of roles beyond that of the skilled clinician. Faculty development (FD) encompasses the broad range of activities that institutions use to renew skill-sets and assist faculty members in these multiple roles. This study seeks to define the current FD needs and interests of Canadian academic emergency physicians (AEPs).
An online survey was administered to 943 AEPs in eight centers across Canada to determine their current FD activities, provide a detailed understanding of their FD needs and interests, elucidate the perceived barriers to and motivation for engaging in FD, and identify preferred methods of delivery for FD activities.
This national, cross-sectional survey was completed by 336 respondents. It shows that need for FD is universally high, particularly in traditional domains of scholarship, leadership and education (79%, 80%, 87% overall interest, respectively). However, the study also suggests that there is increasing need for FD in areas where current participation is lowest, namely research and social accountability (12% and 13% more interest, respectively). Senior and junior faculty evince equivalent overall FD interest (p>0.05), whereas female AEPs expressed greater overall FD needs in leadership (1.82 vs 1.44 activities, p=0.003) than males. Continued participation in FD activities is best promoted by offering relevant topics, at convenient times and locations.
This study reports the first comprehensive national FD needs assessment of Canadian academic emergency physicians.