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Early Manuscripts Electronic Library

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Research output, citation impact, and the most-cited recent papers from Early Manuscripts Electronic Library (United States). Aggregated across the NobleBlocks index of 300M+ scholarly works.

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Early Manuscripts Electronic Library

Top-cited papers from Early Manuscripts Electronic Library

Stanford Presenteeism Scale: Health Status and Employee Productivity
Cheryl Koopman, Kenneth R. Pelletier, James F. Murray, Claire Sharda +4 more
2002· Journal of Occupational and Environmental Medicine808doi:10.1097/00043764-200201000-00004

Workforce productivity has become a critical factor in the strength and sustainability of a company's overall business performance. Absenteeism affects productivity; however, even when employees are physically present at their jobs, they may experience decreased productivity and below-normal work quality--a concept known as decreased presenteeism. This article describes the creation and testing of a presenteeism scale evaluating the impact of health problems on individual performance and productivity. A total of 175 county health employees completed the 34-item Stanford Presenteeism Scale (SPS-34). Using these results, we identified six key items to describe presenteeism, resulting in the SPS-6. The SPS-6 has excellent psychometric characteristics, supporting the feasibility of its use in measuring health and productivity. Further validation of the SPS-6 on actual presenteeism (work loss data) or health status (health risk assessment or utilization data) is needed.

Nonseparable, Stationary Covariance Functions for Space–Time Data
Tilmann Gneiting
2002· Journal of the American Statistical Association781doi:10.1198/016214502760047113

Geostatistical approaches to spatiotemporal prediction in environmental science, climatology, meteorology, and related fields rely on appropriate covariance models. This article proposes general classes of nonseparable, stationary covariance functions for spatiotemporal random processes. The constructions are directly in the space–time domain and do not depend on closed-form Fourier inversions. The model parameters can be associated with the data's spatial and temporal structures, respectively; and a covariance model with a readily interpretable space–time interaction parameter is fitted to wind data from Ireland.

Greenhouse gas emissions from lakes and impoundments: Upscaling in the face of global change
Tonya DelSontro, Jake J. Beaulieu, John Downing
2018· Limnology and Oceanography Letters579doi:10.1002/lol2.10073

Abstract Lakes and impoundments are important sources of greenhouse gases (GHG: i.e., CO 2 , CH 4 , N 2 O), yet global emission estimates are based on regionally biased averages and elementary upscaling. We assembled the largest global dataset to date on emission rates of all three GHGs and found they covary with lake size and trophic state. Fitted models were upscaled to estimate global emission using global lake size inventories and a remotely sensed global lake productivity distribution. Traditional upscaling approaches overestimated CO 2 and N 2 O emission but underestimated CH 4 by half. Our upscaled size‐productivity weighted estimates (1.25–2.30 Pg of CO 2 ‐equivalents annually) are nearly 20% of global CO 2 fossil fuel emission with ∼ 75% of the climate impact due to CH 4 . Moderate global increases in eutrophication could translate to 5–40% increases in the GHG effects in the atmosphere, adding the equivalent effect of another 13% of fossil fuel combustion or an effect equal to GHG emissions from current land use change.

Delirium in critically ill patients
Mark van den Boogaard, Lisette Schoonhoven, Andrea W.M. Evers, Johannes G. van der Hoeven +2 more
2011· Critical Care Medicine367doi:10.1097/ccm.0b013e31822e9fc9

OBJECTIVE: To examine the impact of delirium during intensive care unit stay on long-term health-related quality of life and cognitive function in intensive care unit survivors. DESIGN: Prospective 18-month follow-up study. SETTING: Four intensive care units of a university hospital. PATIENTS: A median of 18 months after intensive care discharge, questionnaires were sent to 1,292 intensive care survivors with (n = 272) and without (n = 1020) delirium during their intensive care stay. MEASUREMENTS AND MAIN RESULTS: The Short Form-36v1, checklist individual strength-fatigue, and cognitive failure questionnaire were used. Covariance analysis was performed to adjust for relevant covariates. Of the 915 responders, 171 patients were delirious during their intensive care stay (median age 65 [interquartile range 58-85], Acute Physiology and Chronic Health Evaluation II score 17 [interquartile range 14-20]), and 745 patients were not (median age 65 [interquartile range 57-72], Acute Physiology and Chronic Health Evaluation II score 13 [interquartile range 10-16]). After adjusting for covariates, no differences were found between delirium and nondelirium survivors on the Short Form-36 and checklist individual strength-fatigue. However, survivors who had suffered from delirium reported that they made significantly more social blunders, and their total cognitive failure questionnaire score was significantly higher, compared to survivors who had not been delirious. Survivors of a hypoactive delirium subtype performed significantly better on the domain mental health than mixed and hyperactive delirium patients. Duration of delirium was significantly correlated to problems with memory and names. CONCLUSIONS: Intensive care survivors with delirium during their intensive care unit stay had a similar adjusted health-related quality of life evaluation, but significantly more cognitive problems than those who did not suffer from delirium, even after adjusting for relevant covariates. In addition, the duration of delirium was related to long-term cognitive problems.

Hemidiaphragmatic Paresis During Interscalene Brachial Plexus Block
William F. Urmey, Marianne McDonald
1992· Anesthesia & Analgesia324doi:10.1213/00000539-199203000-00006

We studied the effects of unilateral hemidiaphragmatic paresis caused by interscalene brachial plexus block on routine pulmonary function in eight patients. In an additional four patients, we studied changes in chest wall motion during interscalene block anesthesia by chest wall magnetometry. Ipsilateral hemidiaphragmatic paresis, as diagnosed by ultrasonography, developed in all patients within 5 min of interscalene injection of 45 mL of 1.5% mepivacaine with added epinephrine and bicarbonate. Large decreases in all pulmonary function variables were measured in every patient. Forced vital capacity and forced expiratory volume at 1 s decreased 27% +/- 4.3% and 26.4% +/- 6.8%, respectively (P = 0.0001). Peak expiratory and maximum midexpiratory flow rates were also significantly reduced. Interscalene block caused changes in pulmonary function and chest wall mechanical motion that were similar to those published in previous studies on patients with hemidiaphragmatic paresis of pathological or surgical etiology. Interscalene block probably should not be performed in patients who are dependent on intact diaphragmatic function and in those patients unable to tolerate a 25% reduction in pulmonary function.

A new constructive logic: classic logic
Jean-Yves Girard
1991· Mathematical Structures in Computer Science310doi:10.1017/s0960129500001328

There are two ways to present this work; the most efficient is of course to start with the main syntactical definitions, and to end with semantics: this is the presentation that we follow in the body of the text: section 1, syntex; section 2, semantics. Another possibility is to follow the order of discovery of the concepts, which (as expected) starts with the semantics and ends with the syntex; we adopt this second way for our introduction, hoping that this orthogonal look at the same object will help to apprehend the concepts.

PARTICIPATIVE DECISION MAKING AND EMPLOYEE PERFORMANCE IN DIFFERENT CULTURES: THE MODERATING EFFECTS OF ALLOCENTRISM/IDIOCENTRISM AND EFFICACY.
Simon S. K. Lam, Xiaoping Chen, John Schaubroeck
2002· Academy of Management Journal303doi:10.2307/3069321

The relationship between perceived participative decision making and employee performance was examined in matched samples of employees from the Hong Kong and U.S. branches of one organization. Self-efficacy in regard to participating in decisions and idiocentrism moderated the relationship between perceived participative decision-making opportunity and individual performance. Perceptions of the participation efficacy of a work unit and allocentrism moderated the relationship between participative decision-making opportunity cuid group performance. Idiocentrism and allocentrism appeared to explain regional differences in how participative decision making and efficacy perceptions interacted to predict performance. Participative decision making, defined as joint decision making (Locke & Schweiger, 1979) or influence sharing between hierarchical superiors and their subordinates (Mitchell, 1973), has been a focus of organizational research for nearly 50 years. Whereas many researchers have examined relationships between participative decision making and employee outcomes such as task performance, job satisfaction, and turnover, only equivocal conclusions can be drawn from existing research on the relationship between participative decision making and job performance. Some quantitative reviews have reported moderately positive relationships between these variables (e.g.. Cotton, VoUrath, Froggatt, Lengnick-Hall, & Jennings, 1988; Miller & Monge, 1986). Other quantitative reviews have not found these positive effects (e.g., Wagner, 1994; Wagner & Gooding, 1987a, 1987b). Wagner and Gooding (1987a) inspected the studies cited by Miller and Monge (1986) and found that 90 percent involved percept-percept data collection techniques (that is, data collected from the same respondents using the same questionnaire at the same time). Wagner (1994) reanalyzed Cotton and his coauthors ' (1988) data using meta-analysis and

Essential role of hydride ion in ruthenium-based ammonia synthesis catalysts
Masaaki Kitano, Yasunori Inoue, Hiroki Ishikawa, Kyosuke Yamagata +4 more
2016· Chemical Science299doi:10.1039/c6sc00767h

ions in hydrides at low temperatures suppresses hydrogen poisoning of the Ru surfaces. The present work demonstrates the high potential of metal hydrides as efficient promoters for low-temperature ammonia synthesis.

Depression in patients with hidradenitis suppurativa
Armanda J. Onderdijk, Hessel H. van der Zee, Solveig Esmann, Søren Lophaven +3 more
2012· Journal of the European Academy of Dermatology and Venereology271doi:10.1111/j.1468-3083.2012.04468.x

BACKGROUND: Hidradenitis suppurativa (HS) is a chronic recurrent inflammatory skin disease with abscess formation and scarring predominantly in the inverse areas. The disease is often difficult to treat and patients experience a decreased quality of life (QoL). It is hypothesized that depression is more common in HS patients than among other dermatological patients. OBJECTIVES: To evaluate the prevalence of depression in patients with HS. METHODS: In total 211 HS patients were included in the study and 233 were dermatological control patients. Their QoL and depression scores were assessed using the Dermatology Life Quality Index (DLQI) and the Major Depression Inventory (MDI) questionnaires. HS severity was recorded with a questionnaire and Hurley stages were extracted from the case records. RESULTS: The DLQI was significantly higher for HS patients than for the control patients, 8.4 ± 7.5 vs. 4.3 ± 5.6 (P < 0.0001) and correlated with Hurley stage severity scores. Mean MDI scores were significantly higher for HS patients, 11.0 vs. 7.2 (P < 0.0001). However, clinically defined depression rates according to the International Classification of Diseases, 10th edition (ICD-10) criteria were not significantly higher in HS patients compared to controls (9% vs. 6%). CONCLUSIONS: HS is a chronic skin disease with major impact on QoL even when compared to other dermatological diseases. MDI scores in HS patients correlate with disease severity. This correlation could indicate that the MDI represents a valid measure of disease related morbidity that may serve as an outcome measure in future studies and a relevant point of intervention for individual patients.

Gambling Disorder and Other Behavioral Addictions
Yvonne Yau, Marc N. Potenza
2015· Harvard Review of Psychiatry261doi:10.1097/hrp.0000000000000051

Addiction professionals and the public are recognizing that certain nonsubstance behaviors--such as gambling, Internet use, video-game playing, sex, eating, and shopping--bear resemblance to alcohol and drug dependence. Growing evidence suggests that these behaviors warrant consideration as nonsubstance or "behavioral" addictions and has led to the newly introduced diagnostic category "Substance-Related and Addictive Disorders" in DSM-5. At present, only gambling disorder has been placed in this category, with insufficient data for other proposed behavioral addictions to justify their inclusion. This review summarizes recent advances in our understanding of behavioral addictions, describes treatment considerations, and addresses future directions. Current evidence points to overlaps between behavioral and substance-related addictions in phenomenology, epidemiology, comorbidity, neurobiological mechanisms, genetic contributions, responses to treatments, and prevention efforts. Differences also exist. Recognizing behavioral addictions and developing appropriate diagnostic criteria are important in order to increase awareness of these disorders and to further prevention and treatment strategies.

Conventional Mechanical Ventilation Versus High-frequency Oscillatory Ventilation for Congenital Diaphragmatic Hernia
Kitty G. Snoek, Irma Capolupo, Joost van Rosmalen, Lieke de Jongste-van den Hout +4 more
2015· Annals of Surgery255doi:10.1097/sla.0000000000001533

OBJECTIVES: To determine the optimal initial ventilation mode in congenital diaphragmatic hernia. BACKGROUND: Congenital diaphragmatic hernia is a life-threatening anomaly with significant mortality and morbidity. The maldeveloped lungs have a high susceptibility for oxygen and ventilation damage resulting in a high incidence of bronchopulmonary dysplasia (BPD) and chronic respiratory morbidity. METHODS: An international, multicenter study (NTR 1310), the VICI-trial was performed in prenatally diagnosed congenital diaphragmatic hernia infants (n = 171) born between November 2008 and December 2013, who were randomized for initial ventilation strategy. RESULTS: Ninety-one (53.2%) patients initially received conventional mechanical ventilation and 80 (46.8%) high-frequency oscillation. Forty-one patients (45.1%) randomized to conventional mechanical ventilation died/ had BPD compared with 43 patients (53.8%) in the high-frequency oscillation group. An odds ratio of 0.62 [95% confidence interval (95% CI) 0.25-1.55] (P = 0.31) for death/BPD for conventional mechanical ventilation vs high-frequency oscillation was demonstrated, after adjustment for center, head-lung ratio, side of the defect, and liver position. Patients initially ventilated by conventional mechanical ventilation were ventilated for fewer days (P = 0.03), less often needed extracorporeal membrane oxygenation support (P = 0.007), inhaled nitric oxide (P = 0.045), sildenafil (P = 0.004), had a shorter duration of vasoactive drugs (P = 0.02), and less often failed treatment (P = 0.01) as compared with infants initially ventilated by high-frequency oscillation. CONCLUSIONS: Our results show no statistically significant difference in the combined outcome of mortality or BPD between the 2 ventilation groups in prenatally diagnosed congenital diaphragmatic hernia infants. Other outcomes, including shorter ventilation time and lesser need of extracorporeal membrane oxygenation, favored conventional ventilation.

Cadmium-induced neurotoxicity: still much ado
Alessandra Pacini, Jacopo Junio Valerio Branca, Gabriele Morucci
2018· Neural Regeneration Research246doi:10.4103/1673-5374.239434

Cadmium (Cd) is a highly toxic heavy metal that accumulates in living system and as such is currently one of the most important occupational and environmental pollutants. Cd reaches into the environment by anthropogenic mobilization and it is absorbed from tobacco consumption or ingestion of contaminated substances. Its extremely long biological half-life (approximately 20-30 years in humans) and low rate of excretion from the body cause cadmium storage predominantly in soft tissues (primarily, liver and kidneys) with a diversity of toxic effects such as nephrotoxicity, hepatotoxicity, endocrine and reproductive toxicities. Moreover, a Cd-dependent neurotoxicity has been also related to neurodegenerative diseases such as Alzheimer's and Parkinson's diseases, amyotrophic lateral sclerosis, and multiple sclerosis. At the cellular level, Cd affects cell proliferation, differentiation, apoptosis and other cellular activities. Among all these mechanisms, the Cd-dependent interference in DNA repair mechanisms as well as the generation of reactive oxygen species, seem to be the most important causes of its cellular toxicity. Nevertheless, there is still much to find out about its mechanisms of action and ways to reduce health risks. This article gives a brief review of the relevant mechanisms that it would be worth investigating in order to deep inside cadmium toxicity.

Structure and response patterns of olfactory interneurons in the honeybee, <i>Apis mellifera</i>
Regina Abel, Jürgen Rybak, Randolf Menzel
2001· The Journal of Comparative Neurology228doi:10.1002/cne.1289

To analyze morphologic and physiological properties of olfactory interneurons in the honeybee, Apis mellifera, antennal lobe (AL) neurons were intracellularly recorded and subsequently labeled with Neurobiotin. Additional focal injections were carried out with cobalt hexamine chloride and dextran fluorescent markers. Olfactory interneurons (projection neurons, PNs) project by means of five tracts, the lateral, the median, and three mediolateral antennocerebral tracts (l-, m-, and ml-ACT, respectively) to the mushroom bodies (MBs) and the protocerebral lobe (PL) of the ipsilateral protocerebrum. Uniglomerular PNs of the m- and l-ACT receiving input from a single glomerulus of the AL also arborize in different regions of the AL. The vast majority of l-ACT innervate the T1 region, whereas m-ACT neurons arborize exclusively in the T2, T3, and T4 regions (T1-4 : AL projection area of sensory cells from the antennae). In the calyces of the MB, uniglomerular PNs form varicosities in the basal ring and the lip region. Individual neurons of both types exhibit unequal innervation within and between the two calyces. In addition, m-ACT fibers ramify more densely within the lip neuropil and show a higher incidence of spine-like processes than l-ACTs. In the PL, l-ACTs arborize exclusively within the lateral horn, whereas some m-ACT neurons innervate a broader region. Multiglomerular neurons of the ml-ACT leave the AL by means of three subtracts (ml-ACT 1-3). Two different types can be distinguished according to their protocerebral target areas: ml-ACTs projecting to the lateral PL (LPL) and to the neuropil around the alpha-lobe (tracts 2 and 3) and neurons projecting only to the LPL (tract 1). Intracellular recordings indicate that both l- and m-ACT neurons respond to general odors but with different response properties, indicating that odor information is processed in parallel pathways with different functional characteristics. Just like m-ACT neurons, ml-ACT neurons respond to odors with complex activity patterns. Bilateral interneurons, originating in the suboesophageal ganglion, connect glomeruli of both AL, and send an axon through the m-ACT in each hemisphere of the brain, terminating in the lip region of the calyces. These neurons respond to contact chemical stimuli.

Unboxed objects and polymorphic typing
Xavier Leroy
1992223doi:10.1145/143165.143205

This paper presents a program transformation that allows languages with polymorphic typing (e.g. ML) to be implemented with unboxed, multi-word data representations. The transformation introduces coercions between various representations, based on a typing derivation. A prototype ML compiler utilizing this transformation demonstrates important speedups.

Association of Vitamin D Level With Clinical Status in Inflammatory Bowel Disease: A 5-Year Longitudinal Study
Toufic Kabbani, Ioannis E. Κoutroubakis, Robert E. Schoen, Claudia Ramos–Rivers +4 more
2016· The American Journal of Gastroenterology203doi:10.1038/ajg.2016.53

OBJECTIVES: Emerging data suggest that vitamin D has a significant role in inflammatory bowel disease (IBD). Prospective data evaluating the association of vitamin D serum status and disease course are lacking. We sought to determine the relationship between vitamin D status and clinical course of IBD over a multiyear time period. METHODS: IBD patients with up to 5-year follow-up from a longitudinal IBD natural history registry were included. Patients were categorized according to their mean serum 25-OH vitamin D level. IBD clinical status was approximated with patterns of medication use, health-care utilization, biochemical markers of inflammation (C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR)), pain and clinical disease activity scores, and health-related quality of life. RESULTS: A total of 965 IBD patients (61.9% Crohn's disease, 38.1% ulcerative colitis) formed the study population (mean age 44 years, 52.3% female). Among them, 29.9% had low mean vitamin D levels. Over the 5-year study period, subjects with low mean vitamin D required significantly more steroids, biologics, narcotics, computed tomography scans, emergency department visits, hospital admissions, and surgery compared with subjects with normal mean vitamin D levels (P<0.05). Moreover, subjects with low vitamin D levels had worse pain, disease activity scores, and quality of life (P<0.05). Finally, subjects who received vitamin D supplements had a significant reduction in their health-care utilization. CONCLUSIONS: Low vitamin D levels are common in IBD patients and are associated with higher morbidity and disease severity, signifying the potential importance of vitamin D monitoring and treatment.

Immune Cell Phenotype and Function in Sepsis
Thomas Rimmelé, Didier Payen, Vincenzo Cantaluppi, John C. Marshall +4 more
2015· Shock203doi:10.1097/shk.0000000000000495

Cells of the innate and adaptive immune systems play a critical role in the host response to sepsis. Moreover, their accessibility for sampling and their capacity to respond dynamically to an acute threat increases the possibility that leukocytes might serve as a measure of a systemic state of altered responsiveness in sepsis.The working group of the 14th Acute Dialysis Quality Initiative (ADQI) conference sought to obtain consensus on the characteristic functional and phenotypic changes in cells of the innate and adaptive immune system in the setting of sepsis. Techniques for the study of circulating leukocytes were also reviewed and the impact on cellular phenotypes and leukocyte function of nonextracorporeal treatments and extracorporeal blood purification therapies proposed for sepsis was analyzed.A large number of alterations in the expression of distinct neutrophil and monocyte surface markers have been reported in septic patients. The most consistent alteration seen in septic neutrophils is their activation of a survival program that resists apoptotic death. Reduced expression of HLA-DR is a characteristic finding on septic monocytes, but monocyte antimicrobial function does not appear to be significantly altered in sepsis. Regarding adaptive immunity, sepsis-induced apoptosis leads to lymphopenia in patients with septic shock and it involves all types of T cells (CD4, CD8, and Natural Killer) except T regulatory cells, thus favoring immunosuppression. Finally, numerous promising therapies targeting the host immune response to sepsis are under investigation. These potential treatments can have an effect on the number of immune cells, the proportion of cell subtypes, and the cell function.

The CDC Traumatic Brain Injury Surveillance System
Victor G. Coronado, Karen E. Thomas, Richard W. Sattin, Renee L. Johnson
2005· Journal of Head Trauma Rehabilitation198doi:10.1097/00001199-200505000-00005

OBJECTIVE: To examine the epidemiologic and clinical characteristics of older persons (ie, those aged 65-74, 75-84, and > or = 85 years) hospitalized with traumatic brain injury (TBI). METHODS: Data from the 1999 CDC 15-state TBI surveillance system were analyzed. RESULTS: In 1999, there were 17,657 persons 65 years and older hospitalized with TBI in the 15 states for an age-adjusted rate of 155.9 per 100,000 population. Rates among persons aged 65 years or older increased with age and were higher for males. Most TBIs resulted from fall- or motor vehicle (MV)-traffic-related incidents. Most older persons with TBI had an initial TBI severity of mild (73.4%); however, the proportions of both moderate and severe disability for those discharged alive and of in-hospital mortality were relatively high (23.5%, 9.7%, and 12%, respectively). Persons who fell were also more likely to have had 3 or more comorbid conditions than were those who sustained a TBI from an MV-traffic incident. CONCLUSIONS: TBI is a substantial public health problem among older persons. As the population of older persons continues to increase in the United States, the need to design and implement proven and cost-effective prevention measures that focus on the leading causes of TBI (unintentional falls and MV-traffic incidents) becomes more urgent.

Practice Knowledge and Expertise in the Health Professions
Carmen I. Rios
2002· Pediatric Physical Therapy197doi:10.1097/00001577-200214020-00011

Binghamton, NY Book Reviews:Manuscripts for this department should be sent to Ann F. VanSant, PhD, PT, Editor, Temple University, Department of Physical Therapy, 3307 North Broad Street, Philadelphia, PA 19140. Please provide 2 hard copies and a copy on computer disk, indicating both the computer platform and word processing package used. The manuscript should not exceed 1000 words.

Corticosteroid-dependent eosinophilic oesophagitis: azathioprine and 6-mercaptopurine can induce and maintain long-term remission
Peter Netzer, Juergen M. Gschossmann, Alex Straumann, Alexander Sendensky +2 more
2007· European Journal of Gastroenterology & Hepatology192doi:10.1097/meg.0b013e32825a6ab4

BACKGROUND: Eosinophilic oesophagitis (EO) is a chronic inflammatory disorder of the oesophagus that is rapidly increasing in prevalence. Although systemic and topical corticosteroids are effective in treating EO, some patients develop corticosteroid dependency. Alternative therapeutic approaches that avoid corticosteroids are scarce. AIM: To analyse our experience at inducing and maintaining remission with an immunomodulatory therapy in steroid-dependent EO patients. METHODS: We analysed the clinical and histological response to azathioprine (AZA) and 6-mercaptopurine in three patients with EO (one also with eosinophilic gastroenteritis) and corticosteroid dependency. RESULTS: In all three patients, AZA or 6-mercaptopurine-induced clinical and histological remission that was maintained during the follow-up period (range 3-8 years). Two patients experienced relapses after ceasing AZA therapy. Remission, however, resumed when short-term corticosteroid treatment was followed by AZA. In all the patients, blood eosinophilia disappeared under AZA treatment. Only jumbo biopsies confirmed suspected EO with predominant muscle-layer involvement in one patient. CONCLUSION: In adult patients with corticosteroid-dependent EO, immunomodulatory treatment with purine analogues is a promising therapeutic approach for inducing and maintaining long-term remission without the need for further corticosteroids. Jumbo forcep biopsies might be needed to confirm a diagnosis of muscle-layer predominant EO.

A simulation‐based evaluation of methods for inferring linear barriers to gene flow
Christopher Blair, Dana E. Weigel, Matthew Balazik, Annika T. H. Keeley +4 more
2012· Molecular Ecology Resources189doi:10.1111/j.1755-0998.2012.03151.x

Different analytical techniques used on the same data set may lead to different conclusions about the existence and strength of genetic structure. Therefore, reliable interpretation of the results from different methods depends on the efficacy and reliability of different statistical methods. In this paper, we evaluated the performance of multiple analytical methods to detect the presence of a linear barrier dividing populations. We were specifically interested in determining if simulation conditions, such as dispersal ability and genetic equilibrium, affect the power of different analytical methods for detecting barriers. We evaluated two boundary detection methods (Monmonier's algorithm and WOMBLING), two spatial Bayesian clustering methods (TESS and GENELAND), an aspatial clustering approach (STRUCTURE), and two recently developed, non-Bayesian clustering methods [PSMIX and discriminant analysis of principal components (DAPC)]. We found that clustering methods had higher success rates than boundary detection methods and also detected the barrier more quickly. All methods detected the barrier more quickly when dispersal was long distance in comparison to short-distance dispersal scenarios. Bayesian clustering methods performed best overall, both in terms of highest success rates and lowest time to barrier detection, with GENELAND showing the highest power. None of the methods suggested a continuous linear barrier when the data were generated under an isolation-by-distance (IBD) model. However, the clustering methods had higher potential for leading to incorrect barrier inferences under IBD unless strict criteria for successful barrier detection were implemented. Based on our findings and those of previous simulation studies, we discuss the utility of different methods for detecting linear barriers to gene flow.