bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pseudo‐spectral method using rotated staggered grid for elastic wave propagation in 3D arbitrary anisotropic media
Authors: Zou Peng , Cheng Jiubing 
Published: May 2017

ABSTRACTStaggering grid is a very effective way to reduce the Nyquist errors and to suppress the non‐causal ringing artefacts in the pseudo‐spectral solution of first‐order elastic wave equations. However, the straightforward use of a staggered‐grid pseudo‐spectral method is problematic for simulating wave propagation when the anisotropy level is greater than orthorhombic or when the anisotropic symmetries are not aligned with the computational grids. Inspired by the idea of rotated staggered‐grid finite‐difference method, we propose a modified pseudo‐spectral method for wave propagation in arbitrary anisotropic media. Compared with an existing remedy of staggered‐grid pseudo‐spectral method based on stiffness matrix decomposition and a possible alternative using the Lebedev grids, the rotated staggered‐grid‐based pseudo‐spectral method possesses the best balance between the mitigation of artefacts and efficiency. A 2D example on a transversely isotropic model with tilted symmetry axis verifies its effectiveness to suppress the ringing artefacts. Two 3D examples of increasing anisotropy levels demonstrate that the rotated staggered‐grid‐based pseudo‐spectral method can successfully simulate complex wavefields in such anisotropic formations.
Nitrotoga is selected over Nitrospira in newly assembled biofilm communities from a tap water source community at increased nitrite loading
Authors: Kinnunen Marta , Gülay Arda , Albrechtsen Hans‐Jørgen , Dechesne Arnaud , Smets Barth F. 
Published: May 2017

SummaryCommunity assembly is a central topic in microbial ecology: how do assembly processes interact and what is the relative contribution of stochasticity and determinism? Here, we exposed replicate flow‐through biofilm systems, fed with nitrite‐supplemented tap water, to continuous immigration from a source community, present in the tap water, to determine the extent of selection and neutral processes in newly assembled biofilm communities at both the community and the functional guild (of nitrite‐oxidizing bacteria, NOB) levels. The community composition of biofilms assembled under low and high nitrite loading was described after 40 days of complete nitrite removal. The total community assembly, as well as the NOB guild assembly were largely governed by a combination of deterministic and stochastic processes. Furthermore, we observed deterministic enrichment of certain types of NOB in the biofilms. Specifically, elevated nitrite loading selected for a single Nitrotoga representative, while lower nitrite conditions selected for a number of Nitrospira. Therefore, even when focusing on ecologically coherent ensembles, assembly is the result of complex stochastic and deterministic processes that can only be interrogated by observing multiple assemblies under controlled conditions.
Effects of Sorbic Acid‐Chitosan Microcapsules as Antimicrobial Agent on the Properties of Ethylene Vinyl Alcohol Copolymer Film for Food Packaging
Authors: Hu Shuaifeng , Yu Jie , Wang Zhe , Li Li , Du Yunfei , Wang Liping , Liu Yuan 
Published: May 2017

AbstractThis paper discusses the possibility of using sorbic acid‐chitosan microcapsules (S‐MPs) as an antibacterial component of active ethylene vinyl alcohol copolymer (EVOH) film. S‐MPs with a diameter of approximately 1 to 4 μm showed a sorbic acid loading capacity of 46.5%. Addition of S‐MPs (3%, w/w) increased the tensile strength, haze, oxygen, and water vapor barrier properties, as well as reduced the elongations at break and transmittance of S‐MPs‐EVOH (S‐MP‐EVOH) film. Antibacterial tests showed that the inhibitory capacity of S‐MP‐EVOH film against Salmonella Enteritidis and Escherichia coli was higher than that against Listeria monocytogenes. Moreover, the antibacterial effect of sorbic acid‐EVOH (S‐EVOH) film was stronger than that of S‐MP‐EVOH film. However, S‐MP‐EVOH film demonstrated a longer effective time than S‐EVOH film. Using the total viable counts and total volatile base nitrogen as the judgment standard, S‐MP‐EVOH/polyethylene terephthalate (PET) composite film could extend the shelf life of fish fillets by 4 d at 4 °C, compared with EVOH/PET film. For this reason, S‐MP could be a potential antibacterial component of active films.
A comparison of sedimentary DNA and pollen from lake sediments in recording vegetation composition at the Siberian treeline
Authors: Niemeyer Bastian , Epp Laura S. , Stoof‐Leichsenring Kathleen R. , Pestryakova Luidmila A. , Herzschuh Ulrike 
Published: May 2017

AbstractReliable information on past and present vegetation is important to project future changes, especially for rapidly transitioning areas such as the boreal treeline. To study past vegetation, pollen analysis is common, while current vegetation is usually assessed by field surveys. Application of detailed sedimentary DNA (sedDNA) records has the potential to enhance our understanding of vegetation changes, but studies systematically investigating the power of this proxy are rare to date. This study compares sedDNA metabarcoding and pollen records from surface sediments of 31 lakes along a north–south gradient of increasing forest cover in northern Siberia (Taymyr peninsula) with data from field surveys in the surroundings of the lakes. sedDNA metabarcoding recorded 114 plant taxa, about half of them to species level, while pollen analyses identified 43 taxa, both exceeding the 31 taxa found by vegetation field surveys. Increasing Larix percentages from north to south were consistently recorded by all three methods and principal component analyses based on percentage data of vegetation surveys and DNA sequences separated tundra from forested sites. Comparisons of the ordinations using procrustes and protest analyses show a significant fit among all compared pairs of records. Despite similarities of sedDNA and pollen records, certain idiosyncrasies, such as high percentages of Alnus and Betula in all pollen and high percentages of Salix in all sedDNA spectra, are observable. Our results from the tundra to single‐tree tundra transition zone show that sedDNA analyses perform better than pollen in recording site‐specific richness (i.e., presence/absence of taxa in the vicinity of the lake) and perform as well as pollen in tracing vegetation composition.
Immune modulator therapy for microscopic colitis in a case series of 73 patients
Authors: Cotter T. G. , Kamboj A. K. , Hicks S. B. , Tremaine W. J. , Loftus E. V. , Pardi D. S. 
Published: May 2017

SummaryBackgroundMicroscopic colitis (MC) is a common cause of chronic diarrhoea. Various treatment options have been described, but there are limited data describing outcomes of corticosteroid‐sparing treatments.AimTo evaluate the outcomes of patients with active MC treated with immune modulators.MethodsAll patients seen at Mayo Clinic, Rochester between January 1, 1997 and November 30, 2016 with a histological diagnosis of MC were identified. Patients treated with an immune modulator of interest were selected and clinical outcomes recorded.ResultsSeventy‐three MC patients (50 collagenous colitis and 23 lymphocytic colitis) with a median disease duration of 24 months (range, 7‐60) were included. The indications for treatment were budesonide‐refractoriness in 66%, budesonide dependence in 29%, and budesonide intolerance in 5%. Median age was 51.8 years (range, 43.4‐63.1) and 61 (84%) were female. Thiopurines were used in 49 patients (67%) for a median of 4 months (range, 1.5‐15). Complete and partial response occurred in 43% and 22% respectively. Adverse effects resulting in therapy cessation occurred in 17 patients (35%). Twelve patients (16%) were treated with methotrexate for a median of 14 months (3‐18.8). Complete and partial response occurred in 58% and 17%, respectively. Anti‐TNF therapy was used in 10 patients (14%) for a median of 4 months (range, 2.3‐5.5). Complete response occurred in four patients and partial response in four patients.ConclusionsThe majority of patients with active MC responded to thiopurines, methotrexate, or anti‐TNF therapy. Larger controlled studies are required to confirm the efficacy and safety of these medications in MC.
Systematic review with meta‐analysis: post‐operative complications and mortality risk in liver transplant candidates with obesity
Authors: Barone M. , Viggiani M. T. , Losurdo G. , Principi M. , Leandro G. , Di Leo A. 
Published: May 2017

SummaryBackgroundInternational guidelines rate class III (morbid) obesity (body mass index [BMI]≥40 kg/m2) as a relative contraindication for liver transplantation (LT) requiring further research. Moreover, data on the mortality risk in candidates with a BMI: 30‐34.9 and 35‐39.9 kg/m2 (class I and class II obesity, respectively) are weak.AimTo compare post‐operative complications and mortality risks in all obese candidates vs candidates with a BMI: 18.5‐29.9 (normal/overweight) assumed as controls.MethodsWe searched the Cochrane library, PubMed, Scopus, Web‐of‐Science and article reference lists, restricted to the English language, and selected cohort studies analysing the following outcomes: all‐causes mortality (at 30 days, 1‐2‐3‐5 years), post‐operative and cardiopulmonary complications, hospital and intensive care unit (ICU) length of stay. Two reviewers independently extracted the studies data and a third one resolved discrepancies.ResultsTwenty‐four studies comprising 132 162 patients met the inclusion criteria. As compared to controls, mortality risk was increased at all time‐periods (except at 3 years) for a BMI≥40, at 30 days for a BMI: 30‐34.9 and in none of the considered time‐periods for a BMI: 35‐39.9. Post‐operative complications were significantly higher for a BMI>30 and 30‐34.9. Due to the shortage/absence of data, we evaluated cardiopulmonary complications, hospital and ICU length of stay only in the BMI≥30 category. In these patients, only cardiopulmonary complications were increased as compared to controls.ConclusionsMorbid obesity has an impact on patients’ survival after LT. However, since even a BMI>30 increases post‐transplant complications, new strategies should be included in the LT programme to favour weight loss in all obese candidates.
Instrumental Variables Estimation of Exposure Effects on a Time-to-Event Endpoint Using Structural Cumulative Survival Models
Authors: Martinussen Torben , Vansteelandt Stijn , Tchetgen Tchetgen Eric J. , Zucker David M. 
Published: May 2017

Summary
The use of instrumental variables for estimating the effect of an exposure on an outcome is popular in econometrics, and increasingly so in epidemiology. This increasing popularity may be attributed to the natural occurrence of instrumental variables in observational studies that incorporate elements of randomization, either by design or by nature (e.g., random inheritance of genes). Instrumental variables estimation of exposure effects is well established for continuous outcomes and to some extent for binary outcomes. It is, however, largely lacking for time-to-event outcomes because of complications due to censoring and survivorship bias. In this article, we make a novel proposal under a class of structural cumulative survival models which parameterize time-varying effects of a point exposure directly on the scale of the survival function; these models are essentially equivalent with a semi-parametric variant of the instrumental variables additive hazards model. We propose a class of recursive instrumental variable estimators for these exposure effects, and derive their large sample properties along with inferential tools. We examine the performance of the proposed method in simulation studies and illustrate it in a Mendelian randomization study to evaluate the effect of diabetes on mortality using data from the Health and Retirement Study. We further use the proposed method to investigate potential benefit from breast cancer screening on subsequent breast cancer mortality based on the HIP-study.
Robust Mislabel Logistic Regression without Modeling Mislabel Probabilities
Authors: Hung Hung , Jou Zhi-Yu , Huang Su-Yun 
Published: May 2017

SummaryLogistic regression is among the most widely used statistical methods for linear discriminant analysis. In many applications, we only observe possibly mislabeled responses. Fitting a conventional logistic regression can then lead to biased estimation. One common resolution is to fit a mislabel logistic regression model, which takes into consideration of mislabeled responses. Another common method is to adopt a robust M-estimation by down-weighting suspected instances. In this work, we propose a new robust mislabel logistic regression based on -divergence. Our proposal possesses two advantageous features: (1) It does not need to model the mislabel probabilities. (2) The minimum -divergence estimation leads to a weighted estimating equation without the need to include any bias correction term, that is, it is automatically bias-corrected. These features make the proposed -logistic regression more robust in model fitting and more intuitive for model interpretation through a simple weighting scheme. Our method is also easy to implement, and two types of algorithms are included. Simulation studies and the Pima data application are presented to demonstrate the performance of -logistic regression.
Pain and pain assessment in people with intellectual disability: Issues and challenges in practice
Authors: Doody Owen , E. Bailey Maria 
Published: May 2017

Accessible summary

Pain is difficult to identify when people cannot communicate.

If pain is not identified, it cannot be managed and causes stress.

Pain assessment is essential in order to identify pain.

Pain assessment requires a combination of knowledge, health assessments and observations.

AbstractBackgroundIndividuals with intellectual disability experience the same chronic diseases and conditions as the general population, but are more likely to have physical and psychological co‐morbidities, resulting in a higher risk of experiencing pain and having more frequent or severe pain.MethodThis position paper aims to highlight the importance of pain assessment for people with intellectual disability.ResultsAs people with intellectual disability live within the community and/or remain in the family home, they are accessing a wide range of healthcare services. This necessitates that nurses across all care settings are knowledgeable regarding appropriate/alternative pain assessment methods for people with intellectual disability. While many pain assessment tools are available for use with the intellectual disability population, they are often not well established or infrequently used to establish their validity.ConclusionAlthough self‐report is the gold standard in pain assessment, pain assessment for people with intellectual disability is often challenging as they may be unable to self‐report their pain due to their levels of communication or cognitive ability. Assessment requires a combination of approaches amalgamating: pain assessment, health assessment and observation of behaviours.
Managerial capital, occupational choice and inequality in a global economy
Authors: Dinopoulos Elias , Unel Bulent 
Published: May 2017

AbstractThis study proposes a simple theory of trade with endogenous firm productivity, occupational choice and income inequality. Individuals with different managerial talent choose to become entrepreneurs or workers. Entrepreneurs enhance firm productivity by investing in managerial capital. The model generates three income classes: low‐income workers facing the prospect of unemployment, middle‐income entrepreneurs managing domestic firms and high‐income entrepreneurs managing global firms. Trade liberalization policies raise unemployment and improve welfare. A reduction in per‐unit trade costs raises top incomes and generates labour‐market polarization. A reduction in fixed exporting costs has an ambiguous effect on top incomes and personal income distribution. Policies reducing labour‐market frictions or the costs of managerial‐capital acquisition create more jobs and improve welfare. The income distributional effects of labour‐market policies depend on which policy is implemented.
Access to credit and comparative advantage
Authors: Egger Peter H. , Keuschnigg Christian 
Published: May 2017

AbstractAccess to external funds is crucial for the entry and expansion of entrepreneurial firms and the sectors they predominantly arise in. This paper reports three important results. First, comparative advantage is shaped by factor endowments as well as fundamental determinants of corporate finance. In particular, a larger equity ratio of firms and tough governance standards relax financing constraints, lead to entry of firms at the lower bound of the productivity distribution and create an endogenous comparative advantage in sectors where entrepreneurial firms are clustered. Second, a small degree of protection in the constrained sector can raise a country's welfare by relaxing financing constraints if terms‐of‐trade effects are small. Third, a small degree of protection of the financially dependent industry in a financially underdeveloped country might even raise world welfare.
The potential role of attitudes towards suicide between mental health status and suicidal ideation among Chinese children and adolescents
Authors: Tan L. , Yang Q. H. , Chen J. L. , Zou H. X. , Xia T. S. , Liu Y. 
Published: May 2017

AbstractBackgroundThe objective of this study was to investigate the contributions of mental health status and attitudes towards suicide on suicidal ideation in a sample of 6568 Chinese children and adolescents in China. Attitudes towards suicide were investigated as a possible moderator and mediator of the influence of mental health status on suicidal ideation.MethodsDescriptive statistical analyses, Pearson correlation analyses and hierarchical regression analyses were adopted as methods of data analyses.ResultsApproximately 35.38% of children and adolescents in our study reported having suicidal ideation. Mental health status and attitudes towards suicide both had an independent effect on the severity of suicidal ideation. Results indicated that mental health status was positively associated with suicidal ideation, while attitudes towards suicide were negatively associated with suicidal ideation. Moderation analysis showed that the impact of mental health status on suicidal ideation was significantly greater among children and adolescents who reported favourable attitudes towards suicide. Attitudes towards suicide partially mediated the link between mental health status and the severity of suicidal ideation. Specifically, students who experienced poorer mental health status might be more likely to report significantly more favourable attitudes towards suicide, which in turn promote greater suicidal ideation.ConclusionsThese results have implications for the prevention of youth suicide, suggesting that mental health status and attitudes towards suicide could be important targets for prevention and intervention for children and adolescents at risk of suicidal ideation.
Circulating thyroid cancer biomarkers: Current limitations and future prospects
Authors: Nixon Alexander M. , Provatopoulou Xeni , Kalogera Eleni , Zografos George N. , Gounaris Antonia 
Published: May 2017

SummaryDifferentiated thyroid cancer (DTC) is the most common malignancy of the endocrine system. There has been a significant increase in its incidence over the past two decades attributable mainly to the use of more sensitive diagnostic modalities. Ultrasound‐guided fine needle aspiration cytology is the mainstay of diagnosis of benign disorders and malignancy. However, approximately 20% of lesions cannot be adequately categorized as benign or malignant. In the postoperative setting, monitoring of thyroglobulin (Tg) levels has been employed for the detection of disease recurrence. Unfortunately, Tg antibodies are common and interfere with Tg measurement in this subset of patients. Despite this limitation, Tg remains the sole widely used thyroid cancer biomarker in the clinical setting. In an attempt to bypass antibody interference, research has focused mainly on mRNA targets thought to be exclusively expressed in thyroid cells. Tg and thyroid stimulating hormone receptor (TSHR) mRNA have been extensively studied both for discerning between benign disease and malignancy and in postoperative disease surveillance. However, results among reports have been inconsistent probably reflecting considerable differences in methodology. Recently, microRNA (miRNA) targets are being investigated as potential biomarkers in DTC. MiRNAs are more stable molecules and theoretically are not as vulnerable as mRNA during manipulation. Initial results have been encouraging but large‐scale studies are warranted to verify and elucidate their potential application in diagnosis and postoperative surveillance of thyroid cancer. Several other novel targets, primarily mutations and circulating cells, are currently emerging as promising thyroid cancer circulating biomarkers. Although interesting and intriguing, data are limited and derive from small‐scale studies in specific patient cohorts. Further research findings demonstrating their value are awaited with anticipation.
Critical factors for the recovery of marine mammals
Authors: Lotze Heike K. , Flemming Joanna Mills , Magera Anna M. 
Published: May 2017

Abstract{en} Over the past decades, much research has focused on understanding the critical factors for marine extinctions with the aim of preventing further species losses in the oceans. Although conservation and management strategies are enabling several species and populations to recover, others remain at low abundance levels or continue to decline. To understand these discrepancies, we used a published database on abundance trends of 137 populations of marine mammals worldwide and compiled data on 28 potentially critical factors for recovery. We then applied random forests and additive mixed models to determine which intrinsic and extrinsic factors are critical for the recovery of marine mammals. A mix of life‐history characteristics, ecological traits, phylogenetic relatedness, population size, geographic range, human impacts, and management efforts explained why populations recovered or not. Consistently, species with lower age at maturity and intermediate habitat area were more likely to recover, which is consistent with life‐history and ecological theory. Body size, trophic level, social interactions, dominant habitat, ocean basin, and habitat disturbance also explained some differences in recovery patterns. Overall, a variety of intrinsic and extrinsic factors were important for species’ recovery, pointing to cumulative effects. Our results provide insight for improving conservation and management strategies to enhance recoveries in the future.