bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular identification of Asian lacquers from different trees using Py‐GC/MS and ToF‐SIMS
Authors: Lee Jihye , Jung Se‐Bi , Terlier Tanguy , Lee Kang‐Bong , Lee Yeonhee
Published: May 2018

Traditional Asian lacquers are natural products with highly valued properties, including beauty, gloss, and durability. Pyrolysis‐gas chromatography/mass spectrometry is the technique of choice to study insoluble polymeric lacquer films. In the present study, pyrolysis‐gas chromatography/mass spectrometry results showed that the pyrolysis products of lacquer films were different for all of the studied trees, with urushiol derivatives detected in Toxicodendron vernicifluum from China, Japan, and Korea; laccol in Toxicodendron succedaneum from Vietnam; and thitsiol in Gluta usitata from Myanmar. Time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) was also used to characterize the Asian lacquers, avoiding the time‐consuming and destructive processes of other techniques. The ToF‐SIMS spectra provided structural characterization of a series of urushiol, laccol, and thitsiol derivatives for T vernicifluum from China, Japan, and Korea; T succedaneum from Vietnam; and G usitata from Myanmar, respectively. To differentiate the ToF‐SIMS results for the different Asian lacquer films, principal component analysis was used because it can extract differences in the spectra and indicate what peaks are responsible for these differences. The results indicate that lacquer films from different lacquer trees can be very different. Therefore, ToF‐SIMS with principal component analysis is suitable for the characterization and differentiation of Asian lacquer films in cultural heritage applications.
Different theoretical approaches at optical characterization of randomly rough silicon surfaces covered with native oxide layers
Authors: Ohlídal Ivan , Vohánka Jiří , Mistrík Jan , Čermák Martin , Franta Daniel
Published: May 2018

Results of the optical characterization of randomly rough silicon surfaces covered with native oxide layers based on processing experimental data obtained by ellipsometry and reflectometry are presented. It is shown that the Rayleigh‐Rice theory is suitable theoretical approach for characterizing micro‐rough surfaces in contrast to effective medium approximation. Combination of the Rayleigh‐Rice theory and scalar diffraction theory is efficient and reliable approach for characterizing rougher surfaces with the rms values of heights larger than 10 nm. Thickness of native oxide layers and roughness parameters, ie, the rms values of heights and autocorrelation lengths, are determined for micro‐rough and rougher surfaces using the corresponding theoretical approaches.
Derivative estimation for longitudinal data analysis: Examining features of blood pressure measured repeatedly during pregnancy
Authors: Simpkin Andrew J. , Durban Maria , Lawlor Debbie A. , MacDonald‐Wallis Corrie , May Margaret T. , Metcalfe Chris , Tilling Kate
Published: May 2018

Estimating velocity and acceleration trajectories allows novel inferences in the field of longitudinal data analysis, such as estimating change regions rather than change points, and testing group effects on nonlinear change in an outcome (ie, a nonlinear interaction). In this article, we develop derivative estimation for 2 standard approaches—polynomial mixed models and spline mixed models. We compare their performance with an established method—principal component analysis through conditional expectation through a simulation study. We then apply the methods to repeated blood pressure (BP) measurements in a UK cohort of pregnant women, where the goals of analysis are to (i) identify and estimate regions of BP change for each individual and (ii) investigate the association between parity and BP change at the population level. The penalized spline mixed model had the lowest bias in our simulation study, and we identified evidence for BP change regions in over 75% of pregnant women. Using mean velocity difference revealed differences in BP change between women in their first pregnancy compared with those who had at least 1 previous pregnancy. We recommend the use of penalized spline mixed models for derivative estimation in longitudinal data analysis.
Generalizability of causal inference in observational studies under retrospective convenience sampling
Authors: Hu Zonghui , Qin Jing
Published: May 2018

Many observational studies adopt what we call retrospective convenience sampling (RCS). With the sample size in each arm prespecified, RCS randomly selects subjects from the treatment‐inclined subpopulation into the treatment arm and those from the control‐inclined into the control arm. Samples in each arm are representative of the respective subpopulation, but the proportion of the 2 subpopulations is usually not preserved in the sample data. We show in this work that, under RCS, existing causal effect estimators actually estimate the treatment effect over the sample population instead of the underlying study population. We investigate how to correct existing methods for consistent estimation of the treatment effect over the underlying population. Although RCS is adopted in medical studies for ethical and cost‐effective purposes, it also has a big advantage for statistical inference: When the tendency to receive treatment is low in a study population, treatment effect estimators under RCS, with proper correction, are more efficient than their parallels under random sampling. These properties are investigated both theoretically and through numerical demonstration.
Improved Efficiency of Inverted Perovskite Solar Cells Via Surface Plasmon Resonance Effect of Au@PSS Core‐Shell Tetrahedra Nanoparticles
Authors: Hao Hao , Wang Liang , Ma Xiaoqian , Cao Kun , Yu Hongtao , Wang Minghao , Gu Wenwen , Zhu Rui , Anwar Muhammad Sabieh , Chen Shufen , Huang Wei
Published: May 2018

Sufficient absorption to incident solar illumination, long exciton diffusion length, and efficient dissociation are extremely critical factors to guarantee an acquirement of high power conversion efficiency (PCE) in solar cells, including perovskite solar cells (PSCs). In this work, Au@poly(4‐styrenesulfonate) (PSS) core–shell tetrahedra nanostructures, synthesized by seed mediated growth method, are incorporated into PSCs for the first time to improve light absorption of methylammonium lead iodide via surface plasmon resonance effect. Both the use of Au tetrahedra core and the introduction of ultrathin PSS shell are beneficial for generating a strong local field and preventing from exciton quenching at the surface of nanoparticles (NPs). With an optimal concentration of Au@PSS tetrahedra NPs, the PCE achieves 16.53%, showing a significant improvement factor of 18.83% compared to the reference device without NPs. Analyses indicate that in addition to promotion of light absorption of active layer over the broad wavelength range, the Au@PSS tetrahedra NPs also increase exciton dissociation and charge transfer efficiency by enhancing the recombination resistance inside PSCs and reducing photoluminescence intensity and exciton/carrier lifetime of perovskite films.
A simple reversed‐phase HPLC method for the estimation of dimethylarginines and homocysteine in plasma and serum
Authors: Ravula Venkatesh , Annapurna Singh Sridevi
Published: May 2018

Elevated concentrations of asymmetric dimethylarginine, symmetric dimethylarginine and homocysteine are considered as common risk factors for cardiovascular diseases. A simple reversed‐phase high‐performance liquid chromatography method has been developed to simultaneously detect these biomarkers in plasma and serum. Straightforward sample preparation involves direct derivatization of deproteinized serum/plasma with phenyl isothiocyanate. Dimethylarginines and homocysteine are resolved using a 250 × 4.6 mm I.D, C18 column and a linear gradient of sodium acetate buffer/acetonitrile. Calibration curves of peak area verses concentration are linear with correlation coefficients near unity. The intraday and interday precisions measured by coefficient of variation of peak areas were 1.34–9.7, 2.7–6.7 and 0.3–7.1 for asymmetric dimethylarginine, symmetric dimethylarginine and homocysteine, respectively. The recoveries of asymmetric dimethylarginine, symmetric dimethylarginine and homocysteine are above 86%. Minimal sample preparation, good recoveries and fast run time makes this method suitable for the analysis of plasma and serum.
Starch Modified With Chitosan and Reinforced With Feather Keratin Materials Produced by Extrusion Process: An Alternative to Starch Polymers
Authors: Flores‐Hernandez Cynthia G. , Martinez‐Hernandez Ana L. , Colin‐Cruz Arturo , Martinez‐Bustos Fernando , Castaño Víctor M. , Olivas‐Armendariz Imelda , Almendarez‐Camarillo Armando , Velasco‐Santos Carlos
Published: May 2018

Starch (potato), chitosan, and feather keratin are used for processing biodegradable films produced by extrusion. The morphology of the films is examined with a scanning electron microscope and showed the excellent dispersion of keratin. The dispersion is the result of compatibility between the polysaccharides and proteins, as well as the proper operation of the extrusion process. Water solubility of the starch‐chitosan films decreased with an increase of keratin materials. The storage modulus increased up to 137% for the composites with unmodified ground quill, and by 192% for composites with modified ground quill. In a tensile test, the composites with unmodified and modified quill reached outstanding increments up to 8160 and 7250% in elastic modulus, respectively, compared to the matrix. They also reached up to 3800% and 3150% in maximum strength, respectively, compared to the matrix. The lysozyme test showed relevant changes in the degradability rate, because the weight loss of the films at 3 weeks decreased from 53% for starch‐chitosan matrix and up to 34% for composites with 5 wt% of modified quill. The results corroborated that chicken feather materials can be useful for the development of a manufacturing process for starch composites, and the decomposition of starch‐chitosan composites can be controlled depending on the content and type of keratin.
Protective Effects of Endothelial Progenitor Cell-Derived Extracellular Mitochondria in Brain Endothelium
Authors: Hayakawa Kazuhide , Chan Su Jing , Mandeville Emiri T. , Park Ji Hyun , Bruzzese Morgan , Montaner Joan , Arai Ken , Rosell Anna , Lo Eng H.
Published: May 2018

Endothelial progenitor cells (EPCs) have been pursued as a potential cellular therapy for stroke and central nervous system injury. However, their underlying mechanisms remain to be fully defined. Recent experimental studies suggest that mitochondria may be released and transferred between cells. In this proof-of-concept study, we asked whether beneficial effects of EPCs may partly involve a mitochondrial phenomenon as well. First, EPC-derived conditioned medium was collected and divided into supernatant and particle fractions after centrifugation. Electron microscopy, Western blots, and flow cytometry showed that EPCs were able to release mitochondria. ATP and oxygen consumption assays suggested that these extracellular mitochondria may still be functionally viable. Confocal microscopy confirmed that EPC-derived extracellular mitochondria can be incorporated into normal brain endothelial cells. Adding EPC particles to brain endothelial cells promoted angiogenesis and decreased the permeability of brain endothelial cells. Next, we asked whether EPC-derived mitochondria may be protective. As expected, oxygen–glucose deprivation (OGD) increased brain endothelial permeability. Adding EPC-derived mitochondria particles to the damaged brain endothelium increased levels of mitochondrial protein TOM40, mitochondrial DNA copy number, and intracellular ATP. Along with these indirect markers of mitochondrial transfer, endothelial tightness was also restored after OGD. Taken together, these findings suggest that EPCs may support brain endothelial energetics, barrier integrity, and angiogenic function partly through extracellular mitochondrial transfer.
Enhancements in full‐field PIXE imaging—Large area elemental mapping with increased lateral resolution devoid of optics artefacts
Authors: Buchriegler Josef , Klingner Nico , Hanf Daniel , Munnik Frans , Nowak Stanisław H. , Scharf Oliver , Ziegenrücker René , Renno Axel D. , Borany Johannes von
Published: May 2018

The combination of a pn‐junction charge‐coupled device‐based pixel detector with a poly‐capillary X‐ray optics was installed and examined at the Helmholtz‐Zentrum Dresden‐Rossendorf. The set‐up is intended for particle‐induced X‐ray emission imaging to survey the trace elemental composition of flat/polished geological samples. In the standard configuration, a straight X‐ray optics (20 μm capillary diameter) is used to guide the emitted photons from the sample towards the detector with nearly 70 000 pixels. Their dimensions of 48 × 48 μm2 are the main limitation of the lateral resolution. This limitation can be bypassed by applying a dedicated subpixel algorithm to recalculate the footprint of the photon's electron cloud in the detector. The lateral resolution is then mainly determined by the capillary's diameter. Nevertheless, images are still superimposed by the X‐ray optics pattern. The optics' capillaries are grouped in hexagonal bundles resulting in a reduced transmission of X‐rays in the boundary regions. This influence can be largely suppressed by combining a series of short measurements at slightly shifted positions using a precision stage and correcting the image data for this shifting. The use of a subpixel grid for the image reconstruction allows a further increase of the spatial resolution. This approach of image‐stacking and multiframe super‐resolution in combination with the subpixel correction algorithm is presented and illustrated with experimental data. Additionally, a flat‐field correction is shown to remove the remaining imaging inhomogeneity caused by non‐uniform X‐ray transmission. The described techniques can be used for all X‐ray spectrometry methods using an X‐ray camera to obtain high‐quality elemental images.
The Hazardous Origin of Photocatalytic Activity of ZnCr2O4
Authors: Poschmann Michael , Schürmann Ulrich , Bensch Wolfgang , Kienle Lorenz
Published: May 2018

The ZnCr2O4 catalysts are synthesized by thermal decomposition of (NH4)2[Zn(NH3)2(CrO4)2] and materials with high surface areas and particle sizes in the nano regime are obtained. A special structural feature of the materials are stacking faults with densities strongly depending on the synthesis temperature, i.e. the lower the temperature the larger the number of stacking faults. The catalyst prepared at the lowest decomposition temperature exhibiting the smallest particle size shows the highest catalytic activity in the photocatalytic degradation of y‐Eosin in a photo‐Fenton process. The results of different analytic methods demonstrate that the high catalytic activity is directly correlated with CrO42– anions generated via photo‐oxidation of the catalyst. Therefore, ZnCr2O4 cannot be regarded as an environmental friendly catalyst for advanced photocatalytic oxidation processes.
Differences in Characteristics and Outcome of Patients with Penetrating Injuries in the USA and the Netherlands: A Multi‐institutional Comparison
Authors: Dijkink Suzan , Krijnen Pieta , Hage Aglaia , Van der Wilden Gwendolyn M. , Kasotakis George , Hartog Dennis den , Salim Ali , Goslings J. Carel , Bloemers Frank W. , Rhemrev Steven J. , King David R. , Velmahos George C. , Schipper Inger B.
Published: May 2018

Introduction

The incidence and nature of penetrating injuries differ between countries. The aim of this study was to analyze characteristics and clinical outcomes of patients with penetrating injuries treated at urban Level‐1 trauma centers in the USA (USTC) and the Netherlands (NLTC).

Methods

In this retrospective cohort study, 1331 adult patients (470 from five NLTC and 861 from three USTC) with truncal penetrating injuries admitted between July 2011 and December 2014 were included. In‐hospital mortality was the primary outcome. Outcome comparisons were adjusted for differences in population characteristics in multivariable analyses.

Results

In USTC, gunshot wound injuries (36.1 vs. 17.4%, p < 0.001) and assaults were more frequent (91.2 vs. 77.7%, p < 0.001). ISS was higher in USTC, but the Revised Trauma Score (RTS) was comparable. In‐hospital mortality was similar (5.0 vs. 3.6% in NLTC, p = 0.25). The adjusted odds ratio for mortality in USTC compared to NLTC was 0.95 (95% confidence interval 0.35–2.54). Hospital stay length of stay was shorter in USTC (difference 0.17 days, 95% CI −0.29 to −0.05, p = 0.005), ICU admission rate was comparable (OR 0.96, 95% CI 0.71–1.31, p = 0.80), and ICU length of stay was longer in USTC (difference of 0.39 days, 95% CI 0.18–0.60, p < 0.0001). More USTC patients were discharged to home (86.9 vs. 80.6%, p < 0.001). Readmission rates were similar (5.6 vs. 3.8%, p = 0.17).

Conclusion

Despite the higher incidence of penetrating trauma, particularly firearm‐related injuries, and higher hospital volumes in the USTC compared to the NLTC, the in‐hospital mortality was similar. In this study, outcome of care was not significantly influenced by differences in incidence of firearm‐related injuries.
Surgical Capacity at District Hospitals in Zambia: From 2012 to 2016
Authors: Cheelo Mweene , Brugha Ruairi , Bijlmakers Leon , Kachimba John , McCauley Tracey , Gajewski Jakub
Published: May 2018

Background

Sub‐Saharan Africa has one of the highest burdens of surgically treatable conditions in the world and the highest unmet need, especially in rural areas. Zambia is one of the countries in the region taking steps to improve surgical care for its rural populations.

Aim

To demonstrate changes in surgical capacity in Zambia’s district hospitals over a 3‐year period and to provide a baseline from which future interventions in surgical care can be assessed.

Methods

A cross‐sectional assessment of surgical capacity, using a modified WHO questionnaire, was administered in first‐level hospitals in nine of Zambia’s ten provinces between November 2012 and February 2013 and again between February and April 2016. The two assessments allowed measurement of changes in surgical workforce, infrastructure, equipment, drugs and consumables; and numbers of major surgical procedures performed over two 12‐month periods prior to the assessments.

Results

There was a significant increase, 2013–2016, in number of theatre staff, from 174 (mean 4.4; SD 1.7) to 235 (mean 6; SD 2.9), P = 0.02. However, the percentage of hospitals with functioning anaesthetic machines dropped from 64 to 41%. There was also a drop in hospitals reporting availability of instruments, drugs and consumables from 38 to 24 (97–62%) and from 28 to 24 (72–62%), respectively. The median number of caesarean sections in 2012 was 99 [interquartile range (IQR) 42–187] and 100 (IQR 42–126) in 2015 (P value =0.53). The median number of major surgical procedures in 2012 was 54 (IQR 10–113) and 66 (IQR 18–168) in 2015 (P = 0.45).

Conclusion

An increase in the first‐level hospital surgical workforce between 2013 and 2016 was accompanied by reductions in essential equipment and consumables for surgery, and no changes in surgical output. Periodic monitoring of resource availability is needed to address shortages and make safe surgery available to rural populations.
Disease Burden of Medial Epicondylitis in the USA is Increasing: An Analysis of 19, 856 Patients from 2007 to 2014
Authors: Wiggins Anthony J. , Cancienne Jourdan M. , Camp Christopher L. , Degen Ryan M. , Altchek David W. , Dines Joshua S. , Werner Brian C.
Published: May 2018

Background

Medial epicondylitis (ME), or “golfer's elbow,” is often treated initially by conservative means. Up to 15% of recalcitrant cases require surgical intervention, according to small sample populations, but no national study has determined the incidence of the diagnosis or corroborated the rate of surgical intervention.

Purpose/Question

We sought to review the annual incidence of ME, surgical rates, and health care costs in a population setting.

Methods

A national database was queried for ME from 2007 to 2014. Annual rates and the percentage of diagnosed cases subjected to surgical intervention were recorded. Epidemiologic data was reported with descriptive statistics, and the significant trends over time were analyzed using linear regression.

Results

We identified 19, 856 cases of ME in the study period. There was a significant increase in the annual incidence and overall incidence per 10, 000 patients. The proportion of diagnoses in patients under 65 years of age decreased significantly, while the proportion in those 65 years of age or older significantly increased. The annual number of surgical interventions significantly increased over the study period, although the annual proportion of diagnosed cases proceeding to surgery remained constant. The proportion of patients 65 years of age or older undergoing surgery significantly increased. Total reimbursement for the management of ME during the study period was $1, 877,189. While there was a significant increase in the total annual reimbursement, annual per-patient reimbursement did not change significantly.

Conclusions

While the annual incidence of ME and surgical treatment of ME increased significantly from 2007 to 2014, the proportion of cases treated surgically did not. Notably, the proportion of patients 65 years of age or older diagnosed with and being surgically treated for ME has increased in recent years. Total reimbursement for ME has steadily risen, although per-patient reimbursement rates have not significantly changed.
Education and Physical Health Trajectories in Later Life: A Comparative Study
Authors: Leopold Liliya
Published: May 2018

The cumulative (dis)advantage hypothesis states that health disparities between education groups increase with age. The present study examined this hypothesis in a comparative analysis of the United States, the United Kingdom, the Netherlands, and Sweden. These countries offer sharp contrasts in the social conditions that may intensify or inhibit processes of cumulative (dis)advantage. Using harmonized panel data from the HRS, ELSA, and SHARE, the study applied Poisson multilevel regression models to trace changes in the number of chronic conditions and functional limitations of people aged 50–76 (N = 16,887 individuals; 71,154 observations). The four countries showed a clear gradient in levels of physical health and in the extent to which health trajectories were shaped by education. Across all ages and cohorts, health problems were most prevalent in the United States, less prevalent in the United Kingdom and the Netherlands, and least prevalent in Sweden. A similar cross-national gradient was found for the size of health gaps between education groups and for the extent to which these gaps widened with age. Gaps were largest in the United States, smaller in the United Kingdom and in the Netherlands, and smallest in Sweden.
Comparison of cerebral ventricular volumes and cortical thicknesses in normal rats and Genetic Absence Epilepsy (GAERS): A developmental study
Authors: Kirazlı Özlem , Bay Hüsniye Hacıoğlu , Çakmak Yusuf Özgür , Onat Filiz , Çavdar Safiye
Published: May 2018

Ventricular enlargement and cortical atrophy have been associated with various central nervous system diseases. The aim of the present study was to measure the volumes of the lateral (LV) and third (3V) ventricles and to determine the cortical thickness for the motor (MCx), somatosensory (SSCx), visual (VCx) and auditory (AuCx) cortex and the striatum of Wistar rats, in a developmental series at 10, 20, 30, and 60 days postnatal, and to compare them with similar data from genetic absence epilepsy rats from Strasbourg (GAERS). Serial sections were taken from the brains of Wistar and GAERS animals and were Nissl stained. Photographs were taken from specific sections of the brain for measurements of ventricular volume, cortical and striatal thickness. The image‐j computer program was used for the volume and thickness measurements. The data was statistically analyzed by 3‐way ANOVA using SPSS 15. Comparison of the measurements of GAERS and Wistar animals showed no statistically significant differences at any of the developmental stages regarding the ventricular (LV and 3V) volumes. However, at P60 and P30 of the MCx, P30 of the SSCx, P20 of the VCx and AuCx showed a significantly thinner cortical thickness in the GAERS than in the Wistar animals. The striatal measurements showed significant decrease in thickness of the striatum at P30 and P60. Further, brain size measurements (between the two temporal poles) showed significant decrease in the size at P30 and P60 of GAERS animals. The presence of thinner cortical and striatal thicknesses and smaller brain size in GAERS animals may suggests that these changes could be involved in the mechanism of epileptogenicity or be a result of the epileptogenicity.
Association of glucocerebrosidase polymorphisms and mutations with dementia in incident Parkinson's disease
Authors: Lunde Kristin Aaser , Chung Janete , Dalen Ingvild , Pedersen Kenn Freddy , Linder Jan , Domellöf Magdalena E. , Elgh Eva , Macleod Angus D. , Tzoulis Charalampos , Larsen Jan Petter , Tysnes Ole‐Bjørn , Forsgren Lars , Counsell Carl E. , Alves Guido , Maple‐Grødem Jodi
Published: May 2018

Introduction

Both polymorphisms and mutations in glucocerebrosidase (GBA) may influence the development of dementia in patients with Parkinson's disease.

Methods

Four hundred forty‐two patients and 419 controls were followed for 7 years. Dementia was diagnosed using established criteria. Participants were analyzed for GBA genetic variants, including E326K, T369M, and L444P. Associations between GBA carrier status and dementia were assessed with Cox survival analysis.

Results

A total of 12.0% of patients with Parkinson's disease carried a GBA variant, and nearly half (22/53) of them progressed to dementia during follow‐up. Carriers of deleterious GBA mutations (adjusted hazard ratio 3.81, 95% confidence interval 1.35 to 10.72; P = .011) or polymorphisms (adjusted hazard ratio 1.79; 95% confidence interval 1.07 to 3.00; P = .028) progressed to dementia more rapidly than noncarriers.

Discussion

GBA variants are of great clinical relevance for the development of dementia in Parkinson's disease, especially due to the relatively higher frequency of these alleles compared with other risk alleles.
PET staging of amyloidosis using striatum
Authors: Hanseeuw Bernard J. , Betensky Rebecca A. , Mormino Elizabeth C. , Schultz Aaron P. , Sepulcre Jorge , Becker John A. , Jacobs Heidi I.L. , Buckley Rachel F. , LaPoint Molly R. , Vannini Patrizia , Donovan Nancy J. , Chhatwal Jasmeer P. , Marshall Gad A. , Papp Kathryn V. , Amariglio Rebecca E. , Rentz Dorene M. , Sperling Reisa A. , Johnson Keith A. ,   for the Alzheimer's Disease Neuroimaging Initiative,   and the Harvard Aging Brain Study
Published: May 2018

Introduction

Amyloid positron emission tomography (PET) data are commonly expressed as binary measures of cortical deposition. However, not all individuals with high cortical amyloid will experience rapid cognitive decline. Motivated by postmortem data, we evaluated a three‐stage PET classification: low cortical; high cortical, low striatal; and high cortical, high striatal amyloid; hypothesizing this model could better reflect Alzheimer's dementia progression than a model based only on cortical measures.

Methods

We classified PET data from 1433 participants (646 normal, 574 mild cognitive impairment, and 213 AD), explored the successive involvement of cortex and striatum using 3‐year follow‐up PET data, and evaluated the associations between PET stages, hippocampal volumes, and cognition.

Results

Follow‐up data indicated that PET detects amyloid first in cortex and then in striatum. Our three‐category staging including striatum better predicted hippocampal volumes and subsequent cognition than a three‐category staging including only cortical amyloid.

Discussion

PET can evaluate amyloid expansion from cortex to subcortex. Using striatal signal as a marker of advanced amyloidosis may increase predictive power in Alzheimer's dementia research.
STC 3729/2017. Upon Unconstitutionality Actions 3729, 3751; Against Legislative Bill Bulletin No. 9895-11
Authors: Oquendo Ángel R.
Published: May 2018

While many women have profited from the relatively recent rights-revolution in Latin America, their pregnant sisters have apparently had to sit in the back of the bus or stay off altogether. Even modest progress on abortion entitlements has come at a high price and slow pace, perhaps due to the opposition of an alliance of long-established and up-and-coming religious groups. On a positive note, however, the struggle for emancipation on this front seems to be moving forward. In Chile, the Constitutional Court's (or Tribunal's) opinion of August 28, 2017, STC 3729/2017, which generally upholds a legislative bill allowing a woman to abort in the face of risk to life, lethal prenatal pathology, or rape, provides a case in point. Significantly, it also expands the statutory category of conscientious objectors to include non-professional staff and institutions.
MEDICAL MECHANISMS AND THE RESILIENCE OF PROBABILITIES
Authors: Dragulinescu Stefan
Published: May 2018

This paper argues that there is an important connection between Inference to the Best Explanation and Bayesianism, in the medical context of the interplay between mechanisms and population studies. It is argued that the criteria for evaluating mechanistic evidence can be used in Inference to the Best Explanation and such use thereby increases the resilience of probabilities in a Bayesian framework. This point grows out of the emerging literature on evidence-based medicine and naturally strengthens McCain and Poston's proposal that explanatory information is evidentially relevant.
ENVIRONMENTAL LUCK AND THE STRUCTURE OF UNDERSTANDING
Authors: Boyd Kenneth
Published: May 2018

Conventional wisdom holds that there is no lucky knowledge: if it is a matter of luck, in some relevant sense, that one's belief that p is true, then one does not know that p. Here I will argue that there is similarly no lucky understanding, at least in the case of one type of luck, namely environmental luck. This argument has three parts. First, we need to determine how we evaluate whether one has understanding, which requires determining what I will call understanding's evaluative object. I argue that as the evaluative object of (at least a traditional conception of) knowledge is a belief in a proposition, the evaluative object of understanding is a mental representation of a relational structure. Next, I show that arguments that environmental luck is incompatible with understanding miss the mark by considering cases in which one has a belief in a proposition is lucky to be true, instead of ones in which one's mental representation of a relational structure is lucky to obtain. I agree, then, with those who argue that one can have understanding when one's beliefs are environmentally lucky to be true, but that this compatibility is not relevant when considering the question of whether one can have environmentally lucky understanding. I then present what I take to be a properly constructed case which shows the incompatibility of environmental luck with understanding.
Using the ROSS optical streak camera as a tool to understand laboratory experiments of laser-driven magnetized shock waves
Authors: Liao Andy , Hartigan Patrick , Fiksel Gennady , Blue Brent , Graham Peter , Foster John , Kuranz Carolyn
Published: May 2018

Supersonic flows with high Mach number are ubiquitous in astrophysics. High-powered lasers also have the ability to drive high Mach number, radiating shock waves in laboratory plasmas, and recent experiments along these lines have made it possible to recreate analogs of high Mach-number astrophysical flows under controlled conditions. Streak cameras such as the Rochester optical streak system (ROSS) are particularly helpful in diagnosing such experiments, because they acquire spatially resolved measurements of the radiating gas continuously over a large time interval, making it easy to observe how any shock waves and ablation fronts present in the system evolve with time. This paper summarizes new ROSS observations of a laboratory analog of the collision of a stellar wind with an ablating planetary atmosphere embedded within a magnetosphere. We find good agreement between the observed ROSS data and numerical models obtained with the FLASH code, but only when the effects of optical depth are properly taken into account.
The effects of fluid transport on the creation of a dense cluster of activated fractures in a porous medium
Authors: Alhashim Mohammed G. , Koch Donald L.
Published: May 2018

The formation of a cluster of activated fractures when fluid is injected in a low permeability rock is analysed. A fractured rock is modelled as a dual porosity medium that consists of a growing cluster of activated fractures and the rock’s intrinsic porosity. An integro-differential equation for fluid pressure in the developing cluster of fractures is introduced to account for the pressure-driven flow through the cluster, the loss of fluid into the porous matrix and the evolution of the cluster’s permeability and porosity as the fractures are activated. Conditions under which the dependence of the permeability and porosity on the fluid pressure can be derived from percolation theory are discussed. It is shown that the integro-differential equation admits a similarity solution for the fluid pressure and that the cluster radius grows as a power law of time in two regimes: (i) a short-time regime, when many fractures are activated but pressure-driven flow in the network still dominates over fluid loss; and (ii) a long-time regime, when fluid loss dominates. The power law exponents in the two regimes are functions of the Euclidean dimension of the cluster, percolation universal exponents and the injection protocol. The model predicts that the effects of the fluid properties on the morphology of the formed network are different in the two similarity regimes. For example, increasing the injection rate with time, in the flow dominant regime, produces a smaller cluster of activated fractures than that formed by injecting the fluid at a constant rate. In the fluid loss dominated regime, however, ramping up the injection rate produces a larger cluster.
Large coherence of spanwise velocity in turbulent boundary layers
Authors: de Silva Charitha M. , Kevin Kevin , Baidya Rio , Hutchins Nicholas , Marusic Ivan
Published: May 2018

The spatial signature of spanwise velocity coherence in turbulent boundary layers has been studied using a series of unique large-field-of-view multicamera particle image velocimetry experiments, which were configured to capture streamwise/spanwise slices of the boundary layer in both the logarithmic and the wake regions. The friction Reynolds number of $Re_{\unicode[STIX]{x1D70F}}\approx 2600$ was chosen to nominally match the simulation of Sillero et al. (Phys. Fluids, vol. 26 (10), 2014, 105109), who had previously reported oblique features of the spanwise coherence at the top edge of the boundary layer based on the sign of the spanwise velocity, and here we find consistent observations from experiments. In this work, we show that these oblique features in the spanwise coherence relate to the intermittent turbulent bulges at the edge of the layer, and thus the geometry of the turbulent/non-turbulent interface, with the clear appearance of two counter-oriented oblique features. Further, these features are shown to be also present in the logarithmic region once the velocity fields are deconstructed based on the sign of both the spanwise and the streamwise velocity, suggesting that the often-reported meandering of the streamwise-velocity coherence in the logarithmic region is associated with a more obvious diagonal pattern in the spanwise velocity coherence. Moreover, even though a purely visual inspection of the obliqueness in the spanwise coherence may suggest that it extends over a very large spatial extent (beyond many boundary layer thicknesses), through a conditional analysis, we show that this coherence is limited to distances nominally less than two boundary layer thicknesses. Interpretation of these findings is aided by employing synthetic velocity fields of a boundary layer constructed using the attached eddy model, where the range of eddy sizes can be prescribed. Comparisons between the model, which employs an array of self-similar packet-like eddies that are randomly distributed over the plane of the wall, and the experimental velocity fields reveal a good degree of agreement, with both exhibiting oblique features in the spanwise coherence over comparable spatial extents. These findings suggest that the oblique features in the spanwise coherence are likely to be associated with similar structures to those used in the model, providing one possible underpinning structural composition that leads to this behaviour. Further, these features appear to be limited in spatial extent to only the order of the large-scale motions in the flow.
An experimental study of the motion of a light sphere in a rotating viscous fluid
Authors: Sauma-Pérez T. , Johnson C. G. , Yang L. , Mullin T.
Published: May 2018

We present the results of an experimental investigation of the motion of a light, solid sphere in a horizontal rotating cylinder filled with viscous fluid. At high rotation rates, the sphere sits near the axis of the cylinder. At lower rotation rates, a set of off-axis fixed points are observed for a range of sphere radii. The locations of these fixed points are in quantitative agreement with the predictions of a model based on available theory. The fixed points are observed to become unstable to periodic orbits below a critical Reynolds number $Re_{c}$. The radius of the observed orbits increases with Reynolds number more slowly than a typical Hopf bifurcation, in this case, growing as $1/Re^{2}$.
Flow-induced vibration control of a circular cylinder using rotational oscillation feedback
Authors: Vicente-Ludlam D. , Barrero-Gil A. , Velazquez A.
Published: May 2018

The effect of imposed rotation on a slender elastically mounted circular cylinder free to oscillate transversely to the incident flow has been studied experimentally in a free-surface water channel. Rotation rate and direction are imposed to be proportional to either the cylinder’s transverse displacement or the cylinder’s transverse velocity to determine the effectiveness of these rotation laws to control the dynamics of the cylinder, either to reduce or to enhance oscillations. The former can be of interest for energy harvesting purposes whereas the latter can be useful to avoid unwanted oscillations. In all cases, non-dimensional mass and damping are fixed ($m^{\ast }=11.7$,$\unicode[STIX]{x1D701}=0.0043$) so the analysis is focused on the role of the rotation law and the reduced velocity. The Reynolds number based on the diameter of the cylinder ranges from 1500 to 10 000. Results are presented in terms of steady-state oscillation characterization (say, amplitude and frequency) and wake-pattern topology, which was obtained through digital particle image velocimetry. Both laws are able to either reduce or enhance oscillations, but they do it in a different way. A rotation law proportional to the cylinder’s displacement is more effective to enhance oscillations. For high enough actuation, a galloping-type response has been found, with a persistent growth of the amplitude of oscillations with the reduced velocity that shows a new desynchronized mode of vortex shedding. On the other hand, a rotation law proportional to the cylinder’s transverse velocity is more efficient to reduce oscillations. In this case only vortex-induced-type responses have been found. A quasi-steady theoretical model has been developed, which helps to explain why a galloping-type response may appear when rotation is proportional to cylinder displacement and is able to predict reasonably the amplitude of oscillations in those cases. The model also explains why a galloping-type response is not expected to occur when rotation is proportional to the cylinder’s velocity.
The diversity of professional Canadian Muslim women: Faith, agency, and ‘performing’ identity
Authors: Latif Ruby , Cukier Wendy , Gagnon Suzanne , Chraibi Radia
Published: May 2018

This article examines how identities are constructed and performed by a sample of Muslim women in the Canadian workplace. This research will provide new insights on how Muslim women disclose or ‘perform’ their identities in different contexts. This study will build upon previous research on identity construction of ethnic minorities in the workplace and intersectionality and the workplace experiences of Muslim women by conducting interviews with 23 professional Muslim women in Canada. The findings have important implications for understanding Muslim women’s identity work in broader contexts of discrimination, as well as accommodation and inclusion in organizations.
Trilobite biostratigraphy of the Cambrian 5 and Drumian stages, Series 3 (Laurentian Delamaran, Topazan, and Marjuman stages, Lincolnian Series) of the lower Emigrant Formation at Clayton Ridge, Esmeralda County, Nevada
Authors: Sundberg Frederick A.
Published: May 2018

The Emigrant Formation at Clayton Ridge, Nevada, consists of 420 m of variably interbedded shale, siltstone, and limestone representing an outer shelf environment. It ranges in age from the youngest portion of the Dyeran Stage (Laurentian Waucoban Series; Cambrian Stage 4, Series 2) to Skullrockian Stage (Ibexian Series; Tremadocian Stage, Lower Ordovician). Consequently, it is condensed compared to other localities. For example, the age-equivalent succession in the House Range and the Wendover Range of Utah and Nevada, respectively, is seven times thicker.

The 100 m thick lower limestone and siltstone member of the Emigrant Formation at Clayton Ridge ranges in age from theBolbolenellus euryparia/Nephrolenellus multinodusZone (Laurentian Dyeran Stage) to theCedaria brevifronsZone (Laurentian Marjuman Stage; Drumian Stage; this study). The 40 trilobites described herein from two closely spaced sections of the lower member belong to theGlossopleura walcotti/Ptychagnostus praecurrensZone (Laurentian Delamaran Stage; Stage 5),EhmaniellaZone (Laurentian Topazan Stage; Stage 5), andCedaria selwynitoC.brevifronszones (Laurentian Marjuman Stage; Drumian Stage) zones. The lower Emigrant Formation is <10% as thick as age-equivalent age strata elsewhere in Nevada, California, and Utah. This condensed nature of the lower Emigrant Formation began with the flooding event at the beginning of theOryctocephalus indicusbiochron and the subsequent build-ups of the thick carbonate platforms to the south and northeast.

New species arePagetia aspinosa,P.claytonensis, andSyspacephalus mccollumorum.
New species of lower Tithonian macroconchiateHybonoticerasfrom Mexico and the co-occurrence ofMazapilitesandHybonoticerasin the Mexico-Caribbean area
Authors: Olóriz Federico , Villaseñor Ana Bertha
Published: May 2018

The ammoniteHybonoticeras authariformisnew species [M] is erected from the lower Tithonian of Mexico, adding a new example of endemism for the genusHybonoticerasin records from epicontinental areas. The newly described species is the first evidence of unequivocal lowermost Tithonian macroconchiate hybonoticeratines reported from the Mexico-Caribbean area. Precise biostratigraphic control based on bed-by-bed sampling is first reported for the combined record of macroconchiateHybonoticerasBreistroffer, 1947 withMazapilitesBurckhardt, 1919 in Mexico, indicating an early but not earliest Tithonian age. A preliminary revision of the type material of species assigned to the genusMazapilitespoints to an inconclusive understanding of both intraspecies diversity and the real meaning of the nominal species formulated by Burckhardt, thus revealing defective knowledge about precise biostratigraphy at both the genus and species levels. Published hybonoticeratines and mazapilitines from Mexico and Cuba are revisited to update precise interpretation of their systematics, biostratigraphy, and correlation potential, and to investigate their combined occurrence. Previous information about Cuban hybonoticeratines and mazapilitines is too limited to be conclusively interpreted; their combined record cannot be demonstrated in Cuba. Special relevance is given to a potential occurrence ofMazapilitesin uppermost Kimmeridgian horizons in Cuba. The obtained results update the biostratigraphic meaning and systematic interpretation of the investigated ammonites, and signal topics for future research of interest in their paleobiological and palebiogeographic interpretation.

UUID:http://zoobank.org/References/78c89620-fa2e-4de5-985d-819421a858f9
Explaining Uneven Social Policy Expansion in Democratic Chile
Authors: Castiglioni Rossana
Published: May 2018

This article analyzes the uneven expansion of social policy, using evidence from Chile. It explicates the Chilean case to understand differences between two specific areas of social policy: pensions and healthcare. Most macroexplanatory factors, which the literature proves are crucial for cross-country analysis, are left constant. Instead, it focuses on accounting for differences in the scope of expansion across sectors. It carries out a hypothesis-generating type of case study and relies on inductive process tracing. The goal is to generate hypotheses that may be useful for theory building in the realm of intersectoral dynamics of social policy expansion. The findings suggest that three explanatory factors combine to account for such differences: policymakers’ perceptions of the budgetary constraints and fiscal costs of producing (or failing to produce) a reform; the composition, cohesion, and ideas of technical teams; and the relative power of nongovernmental, prowelfare actors in relation to market stakeholders.
On the Use and Abuse of Spatial Instruments
Authors: Betz Timm , Cook Scott J. , Hollenbach Florian M.
Published: May 2018

Instruments based on realizations of the endogenous variable in other units—for instance, regional or global weighted averages—are commonly used in political science. Such spatial instruments have proved attractive: they are convenient to obtain, typically have power, and are plausibly exogenous. We argue that the assumptions underlying spatial instruments remain poorly understood and challenge whether spatial instruments can satisfy the conditions required for valid instruments. First, when cross-unit dependence exists in the endogenous predictor, other cross-unit relationships—spillovers and interdependence—likely exist as well and risk violations of the exclusion restriction. Second, spatial instruments produce simultaneity in the first-stage equation, as left-hand side outcomes are included as right-hand side predictors. Because the instrument and the endogenous variable are simultaneously determined, the exclusion restriction is, necessarily and by construction, violated. Taken together, these concerns lead us to conclude that spatial instruments are rarely, if ever, valid.