bluuebunny/crossref_metadata_2025_split huggingface dataset:
Physical, Biotic, and Sampling Influences on Diel Habitat Use by Stream-Dwelling Bull Trout
Authors: Banish Nolan P. , Peterson James T. , Thurow Russell F. 
Published: January 2008

Abstract
We used daytime and nighttime underwater observation to assess microhabitat use by bull trout Salvelinus confluentus (N = 213) in streams of the intermountain western USA during the summers of 2001 and 2002. We recorded fish focal points and measured a set of habitat characteristics as well as habitat availability via line transects. Bull trout were benthic and solitary; most (88%) were observed at night. We developed a conditional logistic regression model to account for the effect of fish movement in response to snorkeling, and we fitted 18 candidate models to evaluate the relative influences of biotic and abiotic factors on habitat use. The candidate models were also fitted with a naïve logistic regression (i.e., no movement) to evaluate the effects of movement on inferences of microhabitat use. The most plausible model describing bull trout habitat use was the same for the conditional and naïve regressions and included depth, velocity, percent rubble substratum, and the day × depth, body size × depth, and body size × day × depth interactions. The presence of brook trout S. fontinalis and the abundance of conspecifics did not strongly influence microhabitat use by bull trout. The relative rankings of the remaining models differed substantially between the conditional and naïve models. Relative to the conditional models, the naïve models overestimated the importance of diurnal differences in habitat use and overestimated the use of deepwater habitats, particularly during the day. Both model types suggested that all sizes of bull trout were generally found in deeper, low-velocity habitat at night, whereas small bull trout (70–90 mm total length) were found in shallower habitats during the day. We recommend that biologists account for fish movement in response to sampling to avoid biasing modeled habitat use patterns by bull trout.
Making Meaning on the Screen: Digital Video Production About the Dominican Republic
Authors: Ranker Jason 
Published: January 2008

As part of an inquiry and digital documentary video project, two 12‐year‐old students studied the Dominican Republic. Over the course of their research, the boys (one of whose parents moved from the Dominican Republic) focused their project on two aspects of the culture of the Dominican Republic: contemporary music (bachata and merengue) and famous baseball players who have familial ties to the country.Through the use of digital video software available at the school, the boys produced a digital video by weaving together images from the Web with music and informational audio tracks that they wrote (based upon their research), recorded, and imported into their documentary video project. The article provides a reference point for teachers to try out digital video production in their own classrooms, as well as discussing the importance of such projects in light of the new, digital literacies that they enable students to practice.
Small Increases in the Level of Sox2 Trigger the Differentiation of Mouse Embryonic Stem Cells
Authors: Kopp Janel L. , Ormsbee Briana D. , Desler Michelle , Rizzino Angie 
Published: February 2008

Abstract
Previous studies have demonstrated that the transcription factor Sox2 is essential during the early stages of development. Furthermore, decreasing the expression of Sox2 severely interferes with the self-renewal and pluripotency of embryonic stem (ES) cells. Other studies have shown that Sox2, in conjunction with the transcription factor Oct-3/4, stimulates its own transcription as well as the expression of a growing list of genes (Sox2:Oct-3/4 target genes) that require the cooperative action of Sox2 and Oct-3/4. Remarkably, recent studies have shown that overexpression of Sox2 decreases expression of its own gene, as well as four other Sox2:Oct-3/4 target genes (Oct-3/4, Nanog, Fgf-4, and Utf1). This finding led to the prediction that overexpression of Sox2 in ES cells would trigger their differentiation. In the current study, we initially engineered mouse ES cells for inducible overexpression of Sox2. Using this model system, we demonstrate that small increases (twofold or less) in Sox2 protein trigger the differentiation of ES cells into cells that exhibit markers for a wide range of differentiated cell types, including neuroectoderm, mesoderm, and trophectoderm but not endoderm. We also demonstrate that elevating the levels of Sox2 quickly downregulates several developmentally regulated genes, including Nanog, and a newly identified Sox2:Oct-3/4 target gene, Lefty1. Together, these data argue that the self-renewal of ES cells requires that Sox2 levels be maintained within narrow limits. Thus, Sox2 appears to function as a molecular rheostat that controls the expression of a critical set of embryonic genes, as well as the self-renewal and differentiation of ES cells.
Disclosure of potential conflicts of interest is found at the end of this article.
Expanding Criteria for Resectability of Colorectal Liver Metastases
Authors: Pawlik Timothy M. , Schulick Richard D. , Choti Michael A. 
Published: January 2008

Abstract

Learning Objectives
After completing this course, the reader will be able to: Identify the criteria for hepatic resection of colorectal metastases.Describe strategies for expanding the number of patients who may potentially benefit from hepatic resection.List the factors associated with poor prognosis following hepatic resection.
CME Access and take the CME test online and receive 1 AMA PRA Category 1 Credit™ at CME.TheOncologist.com
Surgical resection is the treatment of choice in patients with colorectal liver metastases, with 5-year survival rates reported in the range of 40%–58%. Over the past 10 years, there has been an impetus to expand the criteria for defining resectability for patients with colorectal metastases. In the past, such features as the number of metastases (three to four), the size of the tumor lesion, and a mandatory 1-cm margin of resection dictated who was “resectable.” More recently, the criteria for resectability have been expanded to include any patient in whom all disease can be removed with a negative margin and who has adequate hepatic volume/reserve. Specifically, instead of resectability being defined by what is removed, decisions concerning resectability now center around what will remain after resection. Under this new paradigm, the number of patients with resectable disease can be expanded by increasing/preserving hepatic reserve (e.g., portal vein embolization, two-stage hepatectomy), combining resection with ablation, and decreasing tumor size (preoperative chemotherapy). The criteria for resectability have also expanded to include patients with extrahepatic disease. Rather than being an absolute contraindication to surgery, patients with both intra- and extrahepatic disease should potentially be considered for resection based on strict selection criteria. The expansion of criteria for resectability of colorectal liver metastases requires a much more nuanced and sophisticated approach to the patient with advanced disease. A therapeutic approach that includes all aspects of multidisciplinary and multimodality care is required to select and treat this complex group of patients.
Racial/Ethnic and Gender Differences in Individual Workplace Injury Risk Trajectories: 1988–1998
Authors: Berdahl Terceira A. 
Published: January 2008

Objectives. I examined workplace injury risk over time and across racial/ethnic and gender groups to observe patterns of change and to understand how occupational characteristics and job mobility influence these changes. Methods. I used hierarchical generalized linear models to estimate individual workplace injury and illness risk over time (“trajectories”) for a cohort of American workers who participated in the National Longitudinal Survey of Youth (1988–1998). Results. Significant temporal variation in injury risk was observed across racial/ethnic and gender groups. At baseline, White men had a high risk of injury relative to the other groups and experienced the greatest decline over time. Latino men demonstrated a pattern of lower injury risk across time compared with White men. Among both Latinos and non-Latino Whites, women had lower odds of injury than did men. Non-Latino Black women's injury risk was similar to Black men's and greater than that for both Latino and non-Latino White women. Occupational characteristics and job mobility partly explained these differences. Conclusions. Disparities between racial/ethnic and gender groups were dynamic and changed over time. Workplace injury risk was associated with job dimensions such as work schedule, union representation, health insurance, job hours, occupational racial segregation, and occupational environmental hazards.
I Think Therefore I Am: Perceived Ideal Weight as a Determinant of Health
Authors: Muennig Peter , Jia Haomiao , Lee Rufina , Lubetkin Erica 
Published: January 2008

Objectives. We examined whether stress related to negative body image perception and the desire to lose weight explained some of the body mass index–health gradient. Methods. We used 2003 Behavioral Risk Factor Surveillance System data to examine the impact of desired body weight, independent of actual body mass index, on the amount of physically and mentally unhealthy days by race, ethnicity, and gender. Results. The difference between actual and desired body weight was a stronger predictor than was body mass index (BMI) of mental and physical health. When we controlled for BMI and age, men who wished to lose 1%, 10%, and 20% of their body weight respectively suffered a net increase of 0.1, 0.9, and 2.7 unhealthy days per month relative to those who were happy with their weight. For women, the corresponding numbers were 0.1, 1.6, and 4.3 unhealthy days per month. The desire to lose weight was more predictive of unhealthy days among women than among men and among Whites than among Blacks or Hispanics. Conclusions. Our results raise the possibility that some of the health effects of the obesity epidemic are related to the way we see our bodies.
Longitudinal Patterns of Health Insurance Coverage Among a National Sample of Children in the Child Welfare System
Authors: Raghavan Ramesh , Aarons Gregory A. , Roesch Scott C. , Leslie Laurel K. 
Published: January 2008

Objectives. We sought to describe health insurance coverage over time among a national sample of children who came into contact with child welfare or child protective services agencies. Methods. We used data from 4 waves of the National Survey of Child and Adolescent Well-Being to examine insurance coverage among 2501 youths. Longitudinal insurance trajectories were identified using latent class analyses, a technique used to classify individuals into groupings of observed variables, and survey-weighted logistic regression was used to identify variables associated with class membership. Results. We identified 2 latent insurance classes—1 contained children who gained health insurance, and the other contained children who stably maintained coverage over time. History of sexual abuse, and race/ethnicity other than White, Black, and Hispanic, were associated with membership in the “gainer” class. Foster care placement and poorer health status were associated with membership in the “maintainer” class. Caregiver characteristics were not associated with class membership. Conclusions. The majority of children in child welfare had stable health insurance coverage over time. Given this vulnerable population’s dependence upon Medicaid, protection of existing entitlements to Medicaid is essential to preserve their stable insurance coverage.
Changes in pH of peritoneal fluid associated with carbon dioxide insufflation during laparoscopic surgery in dogs
Authors: Duerr Felix M. , Twedt David C. , Monnet Eric 
Published: February 2008

Abstract
Objective—To evaluate changes in pH of peritoneal fluid associated with CO2 insufflation during laparoscopy in dogs.
Animals—13 client-owned dogs and 10 purpose-bred teaching dogs.
Procedures—Laparotomy was performed on control dogs; peritoneal fluid pH was mea-sured at time of incision of the abdominal cavity (time 0) and 30 minutes later. Laparoscopic insufflation with CO2 was performed and routine laparoscopic procedures conducted on the teaching dogs. Insufflation pressure was limited to 12 mm Hg. Intraperitoneal fluid pH was measured by use of pH indicator paper at 4 time points. Arterial blood gas analysis was performed at the same time points.
Results—Peritoneal fluid pH did not change significantly between 0 and 30 minutes in the control dogs. For dogs with CO2 insufflation, measurements obtained were a mean of 8.5, 24.5, 44.5, and 72.0 minutes after insufflation. The pH of peritoneal fluid decreased signifi-cantly between the first (7.825 ± 0.350) and second (7.672 ± 0.366) time point. Blood pH decreased significantly between the first (7.343 ± 0.078), third (7.235 ± 0.042), and fourth (7.225 ± 0.038) time points. The PaCO2 increased significantly between the first (39.9 ± 9.8 mm Hg) and fourth (54.6 ± 4.4 mm Hg) time points. Base excess decreased significantly between the first and all subsequent time points.
Conclusions and Clinical Relevance—Pneumoperitoneum attributable to CO2 insufflation caused a mild and transient decrease in peritoneal fluid pH in dogs. Changes in peritoneal fluid associated with CO2 insufflation in dogs were similar to those in other animals.
Outcome of cats with low-grade lymphocytic lymphoma: 41 cases (1995–2005)
Authors: Kiselow Michael A. , Rassnick Kenneth M. , McDonough Sean P. , Goldstein Richard E. , Simpson Kenneth W. , Weinkle Tristan K. , Erb Hollis N. 
Published: February 2008

Abstract
Objective—To evaluate factors associated with response to treatment, remission duration, and survival in cats with low-grade lymphoma affecting various organ systems.
Design—Retrospective case series.
Sample Population—41 cats with histologically confirmed low-grade lymphocytic lymphoma.
Procedures—Medical records and biopsy specimens of cats with histologically confirmed low-grade lymphocytic lymphoma of various organ systems treated with prednisone and chlorambucil between 1995 and 2005 were reviewed. The Kaplan-Meier method was used to estimate remission duration and survival. Factors potentially associated with prognosis were compared.
Results—Common clinical signs were weight loss (83%), vomiting (73%), anorexia (66%), and diarrhea (58%). Seventy-eight percent of cats tested had low serum cobalamin concentrations. Lymphoma was confined to the gastrointestinal tract in 68% of cats. Fifty-six percent of cats achieved a complete response to treatment, and 39% achieved a partial response. Five percent of cats had no response. No association was found between any risk factors (including anatomic site) and response to treatment. Partial response was associated with shorter remission duration, compared with complete response; median remission duration was 428 days for cats achieving a partial response, compared with 897 days for cats achieving a complete response. No other factors were associated with remission duration. Overall median survival time was 704 days. No factors were significantly associated with survival time.
Conclusions and Clinical Relevance—Most cats with lymphocytic lymphoma responded to treatment with prednisone and chlorambucil, and most factors evaluated were not associated with outcome.
Exploring spatiotemporal patterns in early stages of primary succession on former lignite mining sites
Authors: Felinks Birgit , Wiegand Thorsten 
Published: February 2008

AbstractQuestions:1. Does random colonization predominate in early stages of primary succession? 2. Do pioneer species facilitate the establishment of later arriving species? 3. Does an initially random distribution change to an aggregated pattern with ongoing succession?Location:Lignite mining region of Lower Lusatia, eastern Germany.Methods:Individual plants were mapped along a 2 m × 28 m transect during three successive years and classified into two groups (1) the pioneerCorynephorus canescensand (2)‘all other species’. Using the pair‐correlation function, univariate point pattern analysis was carried out by applying a heterogeneous Poisson process as null model. Bivariate analysis and a toroidal shift null model were applied to test for independence between the spatial patterns of the two groups separately for each year, as well by exploring spatiotemporal patterns from different years.Results:In the first yearCorynephorusand ‘all other species’ showed an aggregated pattern on a spatial scale > 40 cm and in the second and third years a significant attraction for distances between 4 and 12 cm, with an increasing radius in the third year. The analyses of interspecific spatiotemporal dynamics revealed a change from independence to attraction between distances of 4 cm and 16 cm when usingCorynephorusas focal species. However, applying ‘all other species’ as focal points results in a significant attraction at distances up to 60 cm in the first year and a diminishing attraction in the second and third years with distances ≤ 6 cm.Conclusions:Facilitative species‐species interactions are present in early stages of primary succession, resulting mainly from pioneer species acting as physical barriers and their ability to capture diaspores being drifted by secondary dispersal along the substrate surface. However, due to gradual establishment of perennial species and their ability of lateral extension by vegetative dispersal, facilitation may influence spatial pattern formation predominantly on short temporal and fine spatial scales.
Selection of line‐transect methods for estimating the density of group‐living animals: lessons from the primates
Authors: Marshall Andrew R. , Lovett Jon C. , White Piran C.L. 
Published: January 2008

AbstractWe review the four major contemporary methods for estimating density of group‐living animals from line‐transect sampling: perpendicular modelling of group centers, perpendicular modelling of center of measurable individuals, strip transects and animal–observer distance. The efficacy of each method is evaluated to produce a simple selection guide. We review the literature and use field data from the Udzungwa Mountains, Tanzania. The review is relevant to all group‐living animals; however, examples are drawn from the primates. Perpendicular methods have better mathematical justification than non‐perpendicular methods. For perpendicular methods using detection function models, it is preferable to measure group location using center of measurable individuals, as group centers are hard to estimate. The assumptions of detection function models are often broken in poor visibility habitats or with unhabituated animals. Alternatively strip transects may be used where there are reliable data on group spread and/or visibility. Strip transects are also the most practical, along with the animal–observer method; however, the latter lacks mathematical justification. We conclude that there are arguments for continued use of all four methods. In certain situations the use of raw encounter rates may also be considered. The appropriate method is determined by minimizing bias and considering time, resources and field conditions. Am. J. Primatol. 70:452–462, 2008. © 2008 Wiley‐Liss, Inc.
Dihydrotetrabenazine positron emission tomography imaging in early, untreated Parkinson's disease
Authors: Martin W. R. Wayne , Wieler Marguerite , Stoessl A. Jon , Schulzer Michael 
Published: January 2008

AbstractObjectiveTo determine the sensitivity of positron emission tomography with11C‐labeled dihydrotetrabenazine (DTBZ) to the nigrostriatal changes associated with early, untreated Parkinson's disease (PD), and to determine the correlation between any regionally reduced DTBZ binding and the major motor features of PD.MethodsUntreated patients with early PD (n = 27) and age‐matched control subjects (n = 33) underwent DTBZ/positron emission tomography scanning to measure binding to the presynaptic type 2 vesicular monoamine transporter site in dopaminergic neurons in basal ganglia regions. Clinical symptoms were rated with the Unified Parkinson's Disease Rating Scale.ResultsMean striatal DTBZ binding values in the patient group were decreased as compared with control subjects (p< 0.001) in all regions examined. The difference between patients and control subjects was most marked in the midputamen, where only one patient had DTBZ binding within 3 standard deviations of the control mean. Bradykinesia and rigidity scores correlated with DTBZ binding in the contralateral midputamen region, particularly for the clinically least affected limbs. Tremor scores showed no significant correlation.InterpretationReduced striatal binding of DTBZ is associated with early PD. Tremor appears to be only partially related to presynaptic dopaminergic function and may have a mechanism differing from that of symptoms such as bradykinesia. The method appears to be most sensitive in mildly affected individuals with a possible “floor” effect that may limit the degree of additional change occurring once more severe clinical symptoms are evident. Ann Neurol 2008
Lewis‐Base‐Katalyse in der organischen Synthese
Authors: Denmark Scott E. , Beutner Gregory L. 
Published: January 2008

AbstractDas Erbe von Gilbert Newton Lewis (1875–1946) ist im Wörterbuch der chemischen Bindung und Reaktivität allgegenwärtig. Die Bedeutung seines Konzepts der Donor‐Akzeptor‐Bindung kommt in den eponymen Grundbegriffen für Elektronenpaarakzeptoren (Lewis‐Säuren) und ‐donoren (Lewis‐Basen) zum Ausdruck. Lewis erkannte, dass Säuren nicht automatisch Wasserstoff enthalten müssen (Brønsted‐Säuren) und trug so zum Sturz des “modernen Protonenkults” bei. Seine Entdeckung läutete zunächst die Entwicklung von Lewis‐Säuren als Reagentien und Katalysatoren für organische Reaktionen ein, in den letzten Jahren wurde aber offensichtlich, dass für diese Zwecke auch Lewis‐Basen eingesetzt werden können. Bezüglich der Beschleunigung chemischer Reaktionen ergänzen Lewis‐Basen die entsprechenden Lewis‐Säuren nicht nur elektronisch: Tatsächlich können Lewis‐Basen die Elektrophilie wie auch die Nucleophilie der Verbindungen verstärken, an die sie gebunden werden. Diese unterschiedliche Reaktivität resultiert in einer bemerkenswerten Vielfalt Lewis‐Base‐katalysierter Reaktionen.
Lewis Base Catalysis in Organic Synthesis
Authors: Denmark Scott E. , Beutner Gregory L. 
Published: January 2008

AbstractThe legacy of Gilbert Newton Lewis (1875–1946) pervades the lexicon of chemical bonding and reactivity. The power of his concept of donor–acceptor bonding is evident in the eponymous foundations of electron‐pair acceptors (Lewis acids) and donors (Lewis bases). Lewis recognized that acids are not restricted to those substances that contain hydrogen (Brønsted acids), and helped overthrow the “modern cult of the proton”. His discovery ushered in the use of Lewis acids as reagents and catalysts for organic reactions. However, in recent years, the recognition that Lewis bases can also serve in this capacity has grown enormously. Most importantly, it has become increasingly apparent that the behavior of Lewis bases as agents for promoting chemical reactions is not merely as an electronic complement of the cognate Lewis acids: in fact Lewis bases are capable of enhancing both the electrophilic and nucleophilic character of molecules to which they are bound. This diversity of behavior leads to a remarkable versatility for the catalysis of reactions by Lewis bases.