To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure email@example.com
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
This chapter provides a brief review of missions using X-ray, gamma-ray, and neutron spectroscopy to determine the chemical composition of planetary surfaces. This chapter presents the history of planetary radiation measurements, including significant discoveries. Summary tables with links to the archived data provide a resource for readers interested in working in this field. Upcoming missions and possible future directions are described.
Some of the greatest successes in infectious disease control rest on empirically grounded models of human and livestock infections. In contrast, disease control in wildlife has not always been as successful. Timely translation of knowledge into proposed management actions remains a challenge in several wildlife disease systems, one of which is pneumonia management in bighorn sheep throughout the North American West. Although pneumonia was recognised as a major impediment to bighorn sheep conservation >80 years ago, a series of challenges stymied the management decision-making process. Despite past obstacles, recent advances from long-term, intensive studies of marked individual sheep have motivated new interest in research-driven strategies for disease management in this system. The system provides an unusual opportunity to study an emerging pathogen disproportionately impacting immature animals through infections that originate from asymptomatically infected adult hosts. We tell the story of bighorn sheep pneumonia, emphasising the obstacles that historically hindered decision-making, the biological or logistical constraints underlying each decision point, and the particular empirical insights that clarified each constraint.
The diet of most adults is low in fish and, therefore, provides limited quantities of the long-chain, omega-3 fatty acids (LCn-3FAs), eicosapentaenoic and docosahexaenoic acids (EPA, DHA). Since these compounds serve important roles in the brain, we sought to determine if healthy adults with low-LCn-3FA consumption would exhibit improvements in neuropsychological performance and parallel changes in brain morphology following repletion through fish oil supplementation.
In a randomized, controlled trial, 271 mid-life adults (30–54 years of age, 118 men, 153 women) consuming ⩽300 mg/day of LCn-3FAs received 18 weeks of supplementation with fish oil capsules (1400 mg/day of EPA and DHA) or matching placebo. All participants completed a neuropsychological test battery examining four cognitive domains: psychomotor speed, executive function, learning/episodic memory, and fluid intelligence. A subset of 122 underwent neuroimaging before and after supplementation to measure whole-brain and subcortical tissue volumes.
Capsule adherence was over 95%, participant blinding was verified, and red blood cell EPA and DHA levels increased as expected. Supplementation did not affect performance in any of the four cognitive domains. Exploratory analyses revealed that, compared to placebo, fish oil supplementation improved executive function in participants with low-baseline DHA levels. No changes were observed in any indicator of brain morphology.
In healthy mid-life adults reporting low-dietary intake, supplementation with LCn-3FAs in moderate dose for moderate duration did not affect neuropsychological performance or brain morphology. Whether salutary effects occur in individuals with particularly low-DHA exposure requires further study.
This review offers an update on research conducted with FinnTwin12 (FT12), the youngest of the three Finnish Twin Cohorts. FT12 was designed as a two-stage study. In the first stage, we conducted multiwave questionnaire research enrolling all eligible twins born in Finland during 1983–1987 along with their biological parents. In stage 2, we intensively studied a subset of these twins with in-school assessments at age 12 and semistructured poly-diagnostic interviews at age 14. At baseline, parents of intensively studied twins were administered the adult version of the interview. Laboratory studies with repeat interviews, neuropsychological tests, and collection of DNA were made of intensively studied twins during follow-up in early adulthood. The basic aim of the FT12 study design was to obtain information on individual, familial and school/neighborhood risks for substance use/abuse prior to the onset of regular tobacco and alcohol use and then track trajectories of use and abuse and their consequences into adulthood. But the longitudinal assessments were not narrowly limited to this basic aim, and with multiwave, multirater assessments from ages 11 to 12, the study has created a richly informative data set for analyses of gene–environment interactions of both candidate genes and genomewide measures with measured risk-relevant environments. Because 25 years have elapsed since the start of the study, we are planning a fifth-wave follow-up assessment.
A wide margin of crop safety is a desirable trait of POST herbicides, and investigation of crop tolerance is a key step in evaluation of new herbicides. Six field experiments were conducted in Ontario, Canada, from 2017 to 2018 to examine the influence of corn (Zea mays L.) hybrid (DKC42-60RIB, DKC43-47RIB, P0094AM, and P9840AM), application rate (1X and 2X), and application timing (PRE, V1, V3, and V5) on the tolerance of field corn to tolpyralate, a new 4-hydroxyphenyl pyruvate dioxygenase inhibitor, co-applied with atrazine. Two corn hybrids (DKC42-60RIB and DKC43-47RIB) exhibited slightly greater visible injury from tolpyralate + atrazine, applied POST, than P0094AM and P9840AM at 1 to 2 wk after application (WAA); hybrids responded similarly with respect to height, grain moisture, and yield. Applications of tolpyralate + atrazine at a 2X rate (80 + 2,000 g ai ha−1) induced greater injury (≤31.6%) than the field rate (40 + 1,000 g ha−1) (≤11.6%); the 2X rate applied at V1 or V3 decreased corn height and slightly increased grain moisture at harvest. On average, field rates resulted in marginally higher grain yields than 2X rates. Based on mixed-model multiple stepwise regression analysis, the air temperature at application, time of day, temperature range in the 24 h before application, and precipitation following application were useful predictor variables in estimating crop injury with tolpyralate + atrazine; however, additional environmental variables also affected crop injury. These results demonstrate the margin of corn tolerance with tolpyralate + atrazine, which provides a basis for optimization of application timing, rate, and corn hybrid selection to mitigate the risk of crop injury with this herbicide tank mixture.
Item 9 of the Patient Health Questionnaire-9 (PHQ-9) queries about thoughts of death and self-harm, but not suicidality. Although it is sometimes used to assess suicide risk, most positive responses are not associated with suicidality. The PHQ-8, which omits Item 9, is thus increasingly used in research. We assessed equivalency of total score correlations and the diagnostic accuracy to detect major depression of the PHQ-8 and PHQ-9.
We conducted an individual patient data meta-analysis. We fit bivariate random-effects models to assess diagnostic accuracy.
16 742 participants (2097 major depression cases) from 54 studies were included. The correlation between PHQ-8 and PHQ-9 scores was 0.996 (95% confidence interval 0.996 to 0.996). The standard cutoff score of 10 for the PHQ-9 maximized sensitivity + specificity for the PHQ-8 among studies that used a semi-structured diagnostic interview reference standard (N = 27). At cutoff 10, the PHQ-8 was less sensitive by 0.02 (−0.06 to 0.00) and more specific by 0.01 (0.00 to 0.01) among those studies (N = 27), with similar results for studies that used other types of interviews (N = 27). For all 54 primary studies combined, across all cutoffs, the PHQ-8 was less sensitive than the PHQ-9 by 0.00 to 0.05 (0.03 at cutoff 10), and specificity was within 0.01 for all cutoffs (0.00 to 0.01).
PHQ-8 and PHQ-9 total scores were similar. Sensitivity may be minimally reduced with the PHQ-8, but specificity is similar.
We consider a theoretical model for the flow of Newtonian fluid through a long flexible-walled channel which is formed from four compliant and rigid compartments arranged alternately in series. We drive the flow using a fixed upstream flux and derive a spatially one-dimensional model using a flow profile assumption. The compliant compartments of the channel are assumed subject to a large external pressure, so the system admits a highly collapsed steady state. Using both a global (linear) stability eigensolver and fully nonlinear simulations, we show that these highly collapsed steady states admit a primary global oscillatory instability similar to observations in a single channel. We also show that in some regions of the parameter space the system admits a secondary mode of instability which can interact with the primary mode and lead to significant changes in the structure of the neutral stability curves. Finally, we apply the predictions of this model to the flow of blood through the central retinal vein and examine the conditions required for the onset of self-excited oscillation. We show that the neutral stability curve of the primary mode of instability discussed above agrees well with canine experimental measurements of the onset of retinal venous pulsation, although there is a large discrepancy in the oscillation frequency.
To measure the association between receipt of specific infection prevention interventions and procedure-related cardiac implantable electronic device (CIED) infections.
Retrospective cohort with manually reviewed infection status.
Setting: National, multicenter Veterans Health Administration (VA) cohort.
Sampling of procedures entered into the VA Clinical Assessment Reporting and Tracking-Electrophysiology (CART-EP) database from fiscal years 2008 through 2015.
A sample of procedures entered into the CART-EP database underwent manual review for occurrence of CIED infection and other clinical/procedural variables. The primary outcome was 6-month incidence of CIED infection. Measures of association were calculated using multivariable generalized estimating equations logistic regression.
We identified 101 procedure-related CIED infections among 2,098 procedures (4.8% of reviewed sample). Factors associated with increased odds of infections included (1) wound complications (adjusted odds ratio [aOR], 8.74; 95% confidence interval [CI], 3.16–24.20), (2) revisions including generator changes (aOR, 2.4; 95% CI, 1.59–3.63), (3) an elevated international normalized ratio (INR) >1.5 (aOR, 1.56; 95% CI, 1.12–2.18), and (4) methicillin-resistant Staphylococcus colonization (aOR, 9.56; 95% CI, 1.55–27.77). Clinically effective prevention interventions included preprocedural skin cleaning with chlorhexidine versus other topical agents (aOR, 0.41; 95% CI, 0.22–0.76) and receipt of β-lactam antimicrobial prophylaxis versus vancomycin (aOR, 0.60; 95% CI, 0.37–0.96). The use of mesh pockets and continuation of antimicrobial prophylaxis after skin closure were not associated with reduced infection risk.
These findings regarding the real-world clinical effectiveness of different prevention strategies can be applied to the development of evidence-based protocols and infection prevention guidelines specific to the electrophysiology laboratory.
Effective POST herbicides and herbicide mixtures are key components of integrated weed management in corn; however, herbicides vary in their efficacy based on application timing. Six field experiments were conducted over 2 yr (2017–2018) in southwestern Ontario, Canada, to determine the effects of herbicide application timing and rate on the efficacy of tolpyralate, a new 4-hydroxyphenyl pyruvate dioxygenase inhibitor. Tolpyralate at 15, 30, or 40 g ai ha−1 in combination with atrazine at 500 or 1,000 g ai ha−1 was applied PRE, early POST, mid-POST, or late POST. Tolpyralate + atrazine at rates ≥30 + 1,000 g ha−1 provided equivalent control of common lambsquarters and Powell amaranth applied PRE or POST, whereas no rate applied PRE controlled common ragweed, velvetleaf, barnyardgrass, or green foxtail. Common ragweed, common lambsquarters, velvetleaf, and Powell amaranth were controlled equally regardless of POST timing. In contrast, control of barnyardgrass and green foxtail declined when herbicide application was delayed to the late-POST timing, irrespective of herbicide rate. Similarly, corn grain yield declined within each tolpyralate + atrazine rate when herbicide applications were delayed to late-POST timing. Overall, the results of this study indicate that several monocot and dicot weed species can be controlled with tolpyralate + atrazine with an early to mid-POST herbicide application timing, before weeds reach 30 cm in height, and Powell amaranth and common lambsquarters can also be controlled PRE. Additionally, this study provides further evidence highlighting the importance of effective, early-season weed control in corn.
Transgenic crops are being developed with herbicide resistance traits to expand innovative weed management solutions for crop producers. Soybean with traits that confer resistance to the hydroxyphenylpyruvate dioxygenase herbicide isoxaflutole is under development and will provide a novel herbicide mode of action for weed management in soybean. Ten field experiments were conducted over 2 years (2017 and 2018) on five soil textures with isoxaflutole-resistant soybean to evaluate annual weed control using one- and two-pass herbicide programs. The one-pass weed control programs included isoxaflutole plus metribuzin, applied PRE, at a low rate (52.5 + 210 g ai ha−1), medium rate (79 + 316 g ai ha−1), and high rate (105 + 420 g ai ha−1); and glyphosate applied early postemergence (EPOST) or late postemergence (LPOST). The two-pass weed control programs included isoxaflutole plus metribuzin, applied PRE, followed by glyphosate applied LPOST, and glyphosate applied EPOST followed by LPOST. At 4 weeks after the LPOST application, control of common lambsquarters, pigweed species, common ragweed, and velvetleaf was variable at 25% to 69%, 49% to 86%, and 71% to 95% at the low, medium, and high rates of isoxaflutole plus metribuzin, respectively. Isoxaflutole plus metribuzin at the low, medium, and high rates controlled grass species evaluated (i.e., barnyardgrass, foxtail, crabgrass, and witchgrass) 85% to 97%, 75% to 99%, and 86% to 100%, respectively. All two-pass weed management programs provided 98% to 100% control of all species. Weed control improved as the rate of isoxaflutole plus metribuzin increased. Two-pass programs provided excellent, full-season annual grass and broadleaf weed control in isoxaflutole-resistant soybean.
Determining infectious cross-transmission events in healthcare settings involves manual surveillance of case clusters by infection control personnel, followed by strain typing of clinical/environmental isolates suspected in said clusters. Recent advances in genomic sequencing and cloud computing now allow for the rapid molecular typing of infecting isolates.
To facilitate rapid recognition of transmission clusters, we aimed to assess infection control surveillance using whole-genome sequencing (WGS) of microbial pathogens to identify cross-transmission events for epidemiologic review.
Clinical isolates of Staphylococcus aureus, Enterococcus faecium, Pseudomonas aeruginosa, and Klebsiella pneumoniae were obtained prospectively at an academic medical center, from September 1, 2016, to September 30, 2017. Isolate genomes were sequenced, followed by single-nucleotide variant analysis; a cloud-computing platform was used for whole-genome sequence analysis and cluster identification.
Most strains of the 4 studied pathogens were unrelated, and 34 potential transmission clusters were present. The characteristics of the potential clusters were complex and likely not identifiable by traditional surveillance alone. Notably, only 1 cluster had been suspected by routine manual surveillance.
Our work supports the assertion that integration of genomic and clinical epidemiologic data can augment infection control surveillance for both the identification of cross-transmission events and the inclusion of missed and exclusion of misidentified outbreaks (ie, false alarms). The integration of clinical data is essential to prioritize suspect clusters for investigation, and for existing infections, a timely review of both the clinical and WGS results can hold promise to reduce HAIs. A richer understanding of cross-transmission events within healthcare settings will require the expansion of current surveillance approaches.
Horseweed biotypes resistant to glyphosate and ALS-inhibiting herbicides are becoming more prevalent in Canada and the United States and present a significant management challenge in field crops. Tolpyralate is a recently commercialized herbicide for use in corn that inhibits 4-hydroxyphenylpyruvate dioxygenase (HPPD), and there is little information regarding its efficacy on horseweed. Six field experiments were conducted in 2017 and 2018 at four locations in Ontario, Canada, to determine the biologically effective dose of tolpyralate and tolpyralate + atrazine and to compare label rates of tolpyralate and tolpyralate + atrazine to currently accepted herbicide standards for POST control of glyphosate and cloransulam-methyl resistant (MR) horseweed. At 8 wk after application (WAA), tolpyralate at 4.8 and 22.6 g ha–1 provided 50% and 80% control, respectively. When applied with atrazine at a 1:33.3 tank-mix ratio, 22.3 + 741.7 g ha–1 provided 95% control of MR horseweed. The addition of atrazine to tolpyralate at label rates improved control of MR horseweed to 98%, which was similar to the control provided by dicamba:atrazine and bromoxynil + atrazine. The results of this study indicate that tolpyralate + atrazine provides excellent control of MR horseweed POST in corn.
Conventional selected area diffraction patterns as obtained in the TEM present difficulties for identification of materials such as asbestifonn minerals, although diffraction data is considered to be one of the preferred methods for making this identification. The preferred orientation of the fibers in each field of measurement, and the spotty patterns that are obtained, do not readily lend themselves to measurement of the integrated intensity values for each dspacing, and even the d-spacings may be hard to determine precisely because the true center location for the broken rings requires estimation. To overcome these problems, we have implemented an automatic method for diffraction pattern measurement. It automatically locates the center of patterns with high precision, measures the radius of each ring of spots in the pattern, and integrates the density of spots in that ring.
The mouth may be presented and understood in different ways, be subject to judgement by others and, as we age, may intrude on everyday life due to problems that affect oral health. However, research that considers older people's experiences concerning their mouths and teeth is limited. This paper reports on qualitative research with 43 people in England and Scotland, aged 65–91, exploring the significance of the mouth over the lifecourse. It uses the concept of ‘mouth talk’ to explore narratives of maintaining, losing and replacing teeth. Participants engaged in ‘mouth talk’ to downplay the impact of the mouth, demonstrate socially appropriate ageing, and distance themselves from ‘real’ old age by retaining a moral identity and sense of self. They also found means to challenge dominant discourses of ageing in how they spoke about missing teeth. Referring to Leder's notion of ‘dys-appearance’ and Gilleard and Higgs’ work on the social imaginary of the fourth age, the study illustrates the ways in which ‘mouth talk’ can contribute to sustaining a sense of self in later life, presenting the ageing mouth, with and without teeth, as an absent presence. It also argues for the importance of listening to stories of the mouth in order to expand understanding of people's approaches to oral health in older age.