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This definitive guide provides advanced students and researchers with a detailed yet accessible overview of all of the central topics of meteor science. Leading figures from the field summarise their active research on themes ranging from the physical composition of meteoroids to the most recent optical and radar observations and ongoing theoretical developments. Crucial practical issues are also considered, such as the risk posed by meteoroids - to spacecraft, and on the ground - and future avenues of research are explored. Taking advantage of the latest dynamical models, insights are offered into meteor flight phenomena and the evolution of meteoroid streams and complexes, as well as describing the in-depth laboratory analysis of recovered material. The rapid rate of progress in twenty-first-century research makes this volume essential reading for anyone who wishes to understand how recent developments broaden our understanding of meteors, meteoroids and their origins.
We have observed the G23 field of the Galaxy AndMass Assembly (GAMA) survey using the Australian Square Kilometre Array Pathfinder (ASKAP) in its commissioning phase to validate the performance of the telescope and to characterise the detected galaxy populations. This observation covers ~48 deg2 with synthesised beam of 32.7 arcsec by 17.8 arcsec at 936MHz, and ~39 deg2 with synthesised beam of 15.8 arcsec by 12.0 arcsec at 1320MHz. At both frequencies, the root-mean-square (r.m.s.) noise is ~0.1 mJy/beam. We combine these radio observations with the GAMA galaxy data, which includes spectroscopy of galaxies that are i-band selected with a magnitude limit of 19.2. Wide-field Infrared Survey Explorer (WISE) infrared (IR) photometry is used to determine which galaxies host an active galactic nucleus (AGN). In properties including source counts, mass distributions, and IR versus radio luminosity relation, the ASKAP-detected radio sources behave as expected. Radio galaxies have higher stellar mass and luminosity in IR, optical, and UV than other galaxies. We apply optical and IR AGN diagnostics and find that they disagree for ~30% of the galaxies in our sample. We suggest possible causes for the disagreement. Some cases can be explained by optical extinction of the AGN, but for more than half of the cases we do not find a clear explanation. Radio sources aremore likely (~6%) to have an AGN than radio quiet galaxies (~1%), but the majority of AGN are not detected in radio at this sensitivity.
Some studies found that providing micronutrient powder (MNP) causes adverse health outcomes; modifying factors are unknown. We aimed to investigate if iron status and inherited hemoglobin disorders (IHbD) modify the impact of MNP on growth and diarrhea among young Lao children. In a double-blind controlled trial, 1704 children ages 6-23mo were randomized to: daily MNP (with 6mg iron plus 14 micronutrients) or placebo for ~36wks. IHbD, and baseline and final hemoglobin (Hb), iron status, and anthropometrics were assessed. Caregivers provided weekly morbidity reports. At enrollment 55.6% were anemic; only 39.3% had no sign of clinically significant IHbD. MNP had no overall impact on growth and longitudinal diarrhea prevalence. Baseline Hb modified the effect of MNP on LAZ (P for interaction=0.082). Among children who were initially non-anemic, final mean LAZ in the MNP group was slightly lower (−1.93 (95%CI: −1.88, −1.97)) vs. placebo (−1.88 (95%CI: −1.83, −1.92)), and the opposite occurred among initially anemic children (final mean LAZ −1.90 (95% CI: −1.86, −1.94) in MNP vs. −1.92 (95% CI: −1.88, −1.96) in placebo). IHbD modified the effect on diarrhea prevalence (P=0.095). Among children with IHbD, the MNP group had higher diarrhea prevalence (1.37 (95%CI: 1.17, 1.59) vs. 1.21 (95%CI: 1.04, 1.41)), while it was lower among children without IHbD who received MNP (1.15 (95%CI: 0.95, 1.39) vs. 1.37 (95%CI: 1.13, 1.64)). In conclusion, there was a small adverse effect of MNP on growth among non-anemic children and on diarrhea prevalence among children with IHbD.
To evaluate the association between novel pre- and post-operative biomarker levels and 30-day unplanned readmission or mortality after paediatric congenital heart surgery.
Children aged 18 years or younger undergoing congenital heart surgery (n = 162) at Johns Hopkins Hospital from 2010 to 2014 were enrolled in the prospective cohort. Collected novel pre- and post-operative biomarkers include soluble suppression of tumorgenicity 2, galectin-3, N-terminal prohormone of brain natriuretic peptide, and glial fibrillary acidic protein. A model based on clinical variables from the Society of Thoracic Surgery database was developed and evaluated against two augmented models.
Unplanned readmission or mortality within 30 days of cardiac surgery occurred among 21 (13%) children. The clinical model augmented with pre-operative biomarkers demonstrated a statistically significant improvement over the clinical model alone with a receiver-operating characteristics curve of 0.754 (95% confidence interval: 0.65–0.86) compared to 0.617 (95% confidence interval: 0.47–0.76; p-value: 0.012). The clinical model augmented with pre- and post-operative biomarkers demonstrated a significant improvement over the clinical model alone, with a receiver-operating characteristics curve of 0.802 (95% confidence interval: 0.72–0.89; p-value: 0.003).
Novel biomarkers add significant predictive value when assessing the likelihood of unplanned readmission or mortality after paediatric congenital heart surgery. Further exploration of the utility of these novel biomarkers during the pre- or post-operative period to identify early risk of mortality or readmission will aid in determining the clinical utility and application of these biomarkers into routine risk assessment.
Effective community engagement in T3–T4 research is widespread, however, similar stakeholder involvement is missing in T1–T2 research. As part of an effort to embed community stakeholders in T1–T2 research, an academic community partnered team conducted discussion groups with researchers to assess perspectives on (1) barriers/challenges to including community stakeholders in basic science, (2) skills/training required for stakeholders and researchers, and (3) potential benefits of these activities. Engaging community in basic science research was perceived as challenging but with exciting potential to incorporate “real-life” community health priorities into basic research, resulting in a new full-spectrum translational research model.
The initial classic Fontan utilising a direct right atrial appendage to pulmonary artery anastomosis led to numerous complications. Adults with such complications may benefit from conversion to a total cavo-pulmonary connection, the current standard palliation for children with univentricular hearts.
A single institution, retrospective chart review was conducted for all Fontan conversion procedures performed from July, 1999 through January, 2017. Variables analysed included age, sex, reason for Fontan conversion, age at Fontan conversion, and early mortality or heart transplant within 1 year after Fontan conversion.
A total of 41 Fontan conversion patients were identified. Average age at Fontan conversion was 24.5 ± 9.2 years. Dominant left ventricular physiology was present in 37/41 (90.2%) patients. Right-sided heart failure occurred in 39/41 (95.1%) patients and right atrial dilation was present in 33/41 (80.5%) patients. The most common causes for Fontan conversion included atrial arrhythmia in 37/41 (90.2%), NYHA class II HF or greater in 31/41 (75.6%), ventricular dysfunction in 23/41 (56.1%), and cirrhosis or fibrosis in 7/41 (17.1%) patients. Median post-surgical follow-up was 6.2 ± 4.9 years. Survival rates at 30 days, 1 year, and greater than 1-year post-Fontan conversion were 95.1, 92.7, and 87.8%, respectively. Two patients underwent heart transplant: the first within 1 year of Fontan conversion for heart failure and the second at 5.3 years for liver failure.
Fontan conversion should be considered early when atrial arrhythmias become common rather than waiting for severe heart failure to ensue, and Fontan conversion can be accomplished with an acceptable risk profile.
In 2013, the national surveillance case definition for West Nile virus (WNV) disease was revised to remove fever as a criterion for neuroinvasive disease and require at most subjective fever for non-neuroinvasive disease. The aims of this project were to determine how often afebrile WNV disease occurs and assess differences among patients with and without fever. We included cases with laboratory evidence of WNV disease reported from four states in 2014. We compared demographics, clinical symptoms and laboratory evidence for patients with and without fever and stratified the analysis by neuroinvasive and non-neuroinvasive presentations. Among 956 included patients, 39 (4%) had no fever; this proportion was similar among patients with and without neuroinvasive disease symptoms. For neuroinvasive and non-neuroinvasive patients, there were no differences in age, sex, or laboratory evidence between febrile and afebrile patients, but hospitalisations were more common among patients with fever (P < 0.01). The only significant difference in symptoms was for ataxia, which was more common in neuroinvasive patients without fever (P = 0.04). Only 5% of non-neuroinvasive patients did not meet the WNV case definition due to lack of fever. The evidence presented here supports the changes made to the national case definition in 2013.
We investigated whether neurobehavioral markers of risk for emotion dysregulation were evident among newborns, as well as whether the identified markers were associated with prenatal exposure to maternal emotion dysregulation. Pregnant women (N = 162) reported on their emotion dysregulation prior to a laboratory assessment. The women were then invited to the laboratory to assess baseline respiratory sinus arrhythmia (RSA) and RSA in response to an infant cry. Newborns were assessed after birth via the NICU Network Neurobehavioral Scale. We identified two newborn neurobehavioral factors—arousal and attention—via exploratory factor analysis. Low arousal was characterized by less irritability, excitability, and motor agitation, while low attention was related to a lower threshold for auditory and visual stimulation, less sustained attention, and poorer visual tracking abilities. Pregnant women who reported higher levels of emotion dysregulation had newborns with low arousal levels and less attention. Larger decreases in maternal RSA in response to cry were also related to lower newborn arousal. We provide the first evidence that a woman's emotion dysregulation while pregnant is associated with risks for dysregulation in her newborn. Implications for intergenerational transmission of emotion dysregulation are discussed.
Introduction: The Prehospital Evidence-Based Practice (PEP) program is an online, freely accessible, continuously updated Emergency Medical Services (EMS) evidence repository. This summary describes the research evidence for the identification and management of adult patients suffering from sepsis syndrome or septic shock. Methods: PubMed was searched in a systematic manner. One author reviewed titles and abstracts for relevance and two authors appraised each study selected for inclusion. Primary outcomes were extracted. Studies were scored by trained appraisers on a three-point Level of Evidence (LOE) scale (based on study design and quality) and a three-point Direction of Evidence (DOE) scale (supportive, neutral, or opposing findings based on the studies’ primary outcome for each intervention). LOE and DOE of each intervention were plotted on an evidence matrix (DOE x LOE). Results: Eighty-eight studies were included for 15 interventions listed in PEP. The interventions with the most evidence were related to identification tools (ID) (n = 26, 30%) and early goal directed therapy (EGDT) (n = 21, 24%). ID tools included Systematic Inflammatory Response Syndrome (SIRS), quick Sequential Organ Failure Assessment (qSOFA) and other unique measures. The most common primary outcomes were related to diagnosis (n = 30, 34%), mortality (n = 40, 45%) and treatment goals (e.g. time to antibiotic) (n = 14, 16%). The evidence rank for the supported interventions were: supportive-high quality (n = 1, 7%) for crystalloid infusion, supportive-moderate quality (n = 7, 47%) for identification tools, prenotification, point of care lactate, titrated oxygen, temperature monitoring, and supportive-low quality (n = 1, 7%) for vasopressors. The benefit of prehospital antibiotics and EGDT remain inconclusive with a neutral DOE. There is moderate level evidence opposing use of high flow oxygen. Conclusion: EMS sepsis interventions are informed primarily by moderate quality supportive evidence. Several standard treatments are well supported by moderate to high quality evidence, as are identification tools. However, some standard in-hospital therapies are not supported by evidence in the prehospital setting, such as antibiotics, and EGDT. Based on primary outcomes, no identification tool appears superior. This evidence analysis can guide selection of appropriate prehospital therapies.
Introduction: Early and accurate diagnosis of critical conditions is essential in emergency medical services (EMS). Serum lactate testing may be used to identify patients with worse prognosis, including sepsis. Recently, the use of a point-of-care lactate (POCL) test has been evaluated in guiding treatment in patients with sepsis. Operating as part of the Prehospital Evidence Based Practice (PEP) Program, the authors sought to identify and describe the body of evidence for POCL use in EMS and the emergency department (ED) for patients with sepsis. Methods: Following PEP methodology, in May 2018, PubMed was searched in a systematic manner. Title and abstract screening were conducted by the program coordinator. These studies were collected, appraised and added to the existing body of literature contained within the PEP database. Evidence appraisal was conducted by two reviewers who assigned both a level of evidence (LOE) on a novel three tier scale and a direction of evidence (supportive, neutral or opposing; based on primary outcome). Data on setting and study design were also extracted. Results: Eight studies were included in our analysis. Three of these studies were conducted in the ED setting; each investigating the POCL test's ability to predict severe sepsis, ICU admission or death. All three studies found supportive results for POCL. A systematic review on the use of POCL in the ED determined that this test can also improve time to treatment. Five of the total 8 studies were conducted prehospitally. Two of these studies were supportive of POCL use in the prehospital setting; in terms of feasibility and the ability to predict sepsis. Both of these study sites used this early information as part of initiating a “sepsis alert” pathway. The other three prehospital studies provide neutral support for POCL. One study demonstrated moderate ability of POCL to predict severe illness. Two studies found poor agreement between prehospital POCL and serum lactate values. Conclusion: Limited low and moderate quality evidence suggest POCL may be feasible and helpful in predicting sepsis in the prehospital setting. However, there is sparse and inconsistent support for specific important outcomes, including accuracy.
In TXRF analysis of impurities in Si wafers, one of the analytical problems is the separation of the peaks of interest (e.g., fluorescence peaks from Fe or Cr) from various background artifacts. These background artifacts include (a) a large Si Kα fluorescence peak, (b) a large peak from the scattered and diffracted primary beam (e.g., W Lβ), (c) a continuum background, (d) scattered radiation in the vicinity of the primary beam peak, (e) an escape peak from the primary beam peak, and (f) spurious Fe and Ni peaks from the detector. This paper will present a scheme for the separation of these components using a fitting procedure based on a commercial spreadsheet.
In interpreting X-ray intensity data from electron probe microanalyzers, the simplest approximation that can be made is that the X-ray intensity is a linear function of concentration. This linear relationship has been found to hold only in very limited cases. Where this simple relationship does not hold, it is generally assumed that increased concentration of an element is reflected in increased intensity of its characteristic X-ray lines. This assumption, which is always valid for binary samples, has been extremely useful, particularly for the interpretation of X-ray scanning pictures. However, in analyses based solely on observed X-ray intensities, large deviations from the linear relationship can make semiquantitative results misleading.
For multielement systems, the deviations from linearity result in ranges of concentration for each element within which increased concentration of the element does not result in an increase of its characteristic X-ray intensity. The magnitude of these deviations, and. hence the ranges of concentration, is related to the X-ray absorption and secondary fluorescence in the sample, which are in turn dependent on instrumental parameters such as X-ray take-off angle. Such inversions in the normal intensity-concentration relationship can result in gross misinterpretation of X-ray scanning pictures on even a qualitative basis. The various factors that lead to deviations from linearity are evaluated, and methods are given for correctly interpreting X-ray intensity data on a qualitative and semiquantitative basis.
The Bureau of Mines purchased the electron optics, vacuum system, and sample stage assembly for the electron-probe X-ray spectrograph and designed and built the two reflection and two transmission scanning curved-crystal spectrometers. The reflection spectrometers were placed in a vacuum chamber for measurements of long-wavelength X-radiation. Operational characteristics of this spectrograph were determined. A low-alloy stainless-steel sample containing 5 wt. % depleted uranium and a stainless-steel sample containing 20 wt. % gadolinium were analyzed.
Residual stress values in a material are governed by the measurements of the atomic spacings in a specific crystallographic plane and the elastic constant for that plane. It has been reported that the value of the elastic constant depends on microstructure, preferred orientation, plastic deformation and morphology , Thus, the theoretical calculation of the elastic constant may deviate from the intrinsic value for a real alloy.