bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of nutrient enrichment and small predator density on seagrass ecosystems: An experimental assessment
Authors: Heck K. L. , Pennock J. R. , Valentine J. F. , Coen L. D. , Sklenar S. A. 
Published: June 2010

We used a field experiment to assess the individual and combined effects of removing top predators and enriching water column nutrients (nitrogen‐N and phosphorus‐P) on seagrass ecosystem structure and function. Experiments were conducted in turtlegrass (Thalassia testudinum) habitats in St. Joseph Bay, FL, an aquatic preserve in the northern Gulf of Mexico that exhibits low ambient nutrient concentrations and contains abundant populations of small crustacean and gastropod mesograzers. We stocked 7.0 m 2 enclosures with elevated (≈4ࢤ8× ambient) densities of juvenile pinfish (Lagodon rhomboides), the dominant fish species in local seagrass habitats, to simulate the first‐order effects of large predator reductions, and we used an in situ delivery system to supplement N and P to ≈3× ambient levels in nutrient addition treatments. Monthly determinations of water column nutrients and Chl a, along with measurements of the biomass and abundance of leaf epiphytes and seagrass production, biomass, and shoot and leaf densities were used to evaluate the relative effects of manipulating nutrient supply and altering food web structure.In contrast to our expectations, results showed few significant nutrient effects, or fish × nutrient enrichment effects on any of the parameters measured. However, there were many significant fish effects, most of which were unexpected. As predicted, increased pinfish density reduced mesograzer numbers significantly. Not anticipated, however, was the reduced epiphyte biomass in fish enclosure treatments, apparently brought about by the pinfish consuming significant amounts of epiphytes as well as mesograzers. This reduction in epiphyte biomass produced positive indirect effects on seagrass biomass, shoot number, and rates of primary productivity in pinfish enclosure treatments.Our results also showed important top‐down effects in determining the composition and abundance of seagrass‐associated plants and animals in this pristine environment. Although we did not observe simple trophic cascades, most likely because pinfish fed at more than one trophic level, and because the dense seagrass prevented small grazers from being reduced to low numbers, pinfish produced important changes in the epibiota as well as the seagrasses themselves. These data, while contrasting with studies reporting significant negative nutrient enrichment effects on seagrasses, support the results of recent experimental studies in showing that: (1) small grazers can often control the abundance of epiphytes; and (2) it is unlikely that a full understanding of the consequences of nutrient enrichment for seagrass ecosystems can be gained without knowing how grazer population are regulated.
Turbulent kinetic energy balance as a tool for estimating vertical diffusivity in wind‐forced stratified waters
Authors: Wüest Alfred , Piepke Gabriel , Van Senden David C. 
Published: June 2010

Based on microstructure measurements in a simply shaped lake basin, the sources of vertical mixing in the stratified part of the water body were identified and estimates of their relative importance obtained by balancing turbulent kinetic energy introduced by the wind. It was found that (1) ∼1.9% of the vertical wind energy flux P10 (∼39 mW m−2), estimated 10 m above the lake surface, was available for turbulent mixing in the entire lake water body; (2) ∼1.5% of P10 was dissipated by turbulence in the weakly stratified surface layer (epilimnion ;6 m deep), and ∼0.42% of P10 reached the stratified deep water (hypolimnion) as turbulent kinetic energy via internal seiching; (3) ∼90% of the turbulent kinetic energy in the stratified water (i.e., 0.38% of P10 ) was dissipated within the bottom boundary layer of a few meters thickness, whereas only ∼10% was lost in the interior (away from the boundary; 0.04% of P10); and (4) as a consequence mixing within the bottom boundary was found to be the main source of vertical mixing for the deep waters of the whole lake. The ratio of buoyancy flux to dissipation (i.e., the mixing efficiency) was found to be ϒmix ∼ 0.15, leading to agreement between the Osborn‐Cox microstructure diffusivities and basin‐wide tracer diffusivities.Comparison with turbulent kinetic energy balances, performed in five other lakes, demonstrates that this analysis is representative for many enclosed water bodies, as long as wind is the dominant source of turbulent energy (i.e., if other processes, such as convective mixing, double diffusion, or riverine intrusions can be neglected). Although the lakes under consideration were very different in size and shape and although the currents in Lake Baikal were inertial rather than seiching related as in the other lakes, the turbulent kinetic energy balance was very similar and the mixing efficiency was identical. Typically, 0.3 ± 0.1% of P10 is transferred as turbulent kinetic energy into the stratified part of the water body, and 0.04 ± 0.02% of P10 is stored as potential energy in the stratification. This analysis provides a tool for estimating vertical diffusivity for wind‐driven hypolimnetic mixing within a factor of two based on stratification and wind measurements alone.
Diffraction Techniques in Structural Biology
Authors: Egli Martin 
Published: June 2010

AbstractA detailed understanding of chemical and biological function and the mechanisms underlying the molecular activities ultimately requires atomic‐resolution structural data. Diffraction‐based techniques such as single‐crystal X‐ray crystallography, electron microscopy, and neutron diffraction are well established and they have paved the road to the stunning successes of modern‐day structural biology. The major advances achieved in the last 20 years in all aspects of structural research, including sample preparation, crystallization, the construction of synchrotron and spallation sources, phasing approaches, and high‐speed computing and visualization, now provide specialists and nonspecialists alike with a steady flow of molecular images of unprecedented detail. The present unit combines a general overview of diffraction methods with a detailed description of the process of a single‐crystal X‐ray structure determination experiment, from chemical synthesis or expression to phasing and refinement, analysis, and quality control. For novices it may serve as a stepping‐stone to more in‐depth treatises of the individual topics. Readers relying on structural information for interpreting functional data may find it a useful consumer guide.Curr. Protoc. Nucleic Acid Chem. 41:7.13.1‐7.13.35. © 2010 by John Wiley & Sons, Inc.
Engineering Three‐Dimensional Collagen Matrices to Provide Contact Guidance during 3D Cell Migration
Authors: Provenzano Paolo P. , Eliceiri Kevin W. , Inman David R. , Keely Patricia J. 
Published: June 2010

AbstractCell invasion requires that cells navigate complex three‐dimensional matrices in vivo. Topological cues are provided and three‐dimensional cell migration and invasion facilitated by the alignment of collagen fibers proximal to tumors. In order to better understand the molecular mechanisms by which cells recognize and migrate along aligned matrices, in vitro assays are needed that recapitulate topological features of the in vivo matrix. Here, we describe two approaches for creating aligned three‐dimensional collagen matrices, both dependent and independent of cell‐mediated alignment. Approaches to quantify alignment and visualize the collagen matrix relative to the cells by second‐harmonic generation are included. These assays are readily adaptable to a variety of cells and biological questions related to three‐dimensional cell migration. Curr. Protoc. Cell Biol. 47:10.17.1‐10.17.11. © 2010 by John Wiley & Sons, Inc.
MultiPipMaker: A Comparative Alignment Server for Multiple DNA Sequences
Authors: Elnitski Laura , Burhans Richard , Riemer Cathy , Hardison Ross , Miller Webb 
Published: June 2010

AbstractThe MultiPipMaker World Wide Web server (http://www.bx.psu.edu) provides a tool for aligning multiple DNA sequences and visualizing regions of conservation among them. This unit describes its use and gives an explanation of the resulting output files and supporting tools. Features provided by the server include alignment of up to 20 very long genomic sequences, output choices of a true, nucleotide‐level multiple alignment and/or stacked, pairwise percent identity plots, and support for user‐specified annotations of genomic features and arbitrary regions, with clickable links to additional information. Input sequences other than the reference can be fragmented, unordered, and unoriented. Curr. Protoc. Bioinform. 30:10.4.1‐10.4.14. © 2010 by John Wiley & Sons, Inc.
Prevalence, practice patterns, and evidence for chronic neck pain
Authors: Goode Adam P. , Freburger Janet , Carey Timothy 
Published: June 2010

AbstractObjectiveTo estimate the prevalence of chronic neck pain in North Carolina, to describe health care use (providers, treatments, and diagnostic testing) for chronic neck pain, and to correlate health care use with the current best evidence.MethodsWe used data from a cross‐sectional telephone survey of a representative sample of North Carolina households in 2006. A total of 5,357 households were contacted in 2006 to identify 141 noninstitutionalized adults ages ≥21 years with chronic neck pain and no chronic low back pain. The subjects were interviewed about their health and health care use (i.e., provider, tests, and treatments). Patterns of health care use were compared with current systematic reviews.ResultsThe estimated prevalence of chronic neck pain in 2006 among noninstitutionalized individuals for the state of North Carolina was 2.2% (95% confidence interval [95% CI] 1.7–2.6). Individuals with chronic neck pain were middle‐aged (mean age 48.9 years) and the majority of subjects were women (56%) and non‐Hispanic white (81%). The subjects saw a mean of 5.21 (95% CI 4.8–5.6) provider types and had a mean of 21 visits. The types of treatments subjects reported varied, with treatments such as electrotherapy stimulation (30.3%), corsets or braces (20.9%), massage (28.1%), ultrasound (27.3%), heat (57.0%), and cold (47.4%) having unclear or little benefit based on the current best available reviews.ConclusionBased on the current evidence for best practice, our findings indicate overutilization of diagnostic testing, narcotics, and modalities, and underutilization of effective treatments such as therapeutic exercise.
Validity and responsiveness of the Michigan hand questionnaire in patients with rheumatoid arthritis: A multicenter, international study
Authors: Waljee Jennifer F. , Chung Kevin C. , Kim H. Myra , Burns Patricia B. , Burke Frank D. , Wilgis E. F. Shaw , Fox David A. 
Published: June 2010

AbstractObjectiveMillions of patients experience the disabling hand manifestations of rheumatoid arthritis (RA), yet few hand‐specific instruments are validated in this population. Our objective was to assess the reliability, validity, and responsiveness of the Michigan Hand Questionnaire (MHQ) in patients with RA.MethodsAt enrollment and at 6 months, 128 RA patients with severe subluxation of the metacarpophalangeal joints completed the MHQ, a 37‐item questionnaire with 6 domains: function, activities of daily living (ADL), pain, work, aesthetics, and satisfaction. Reliability was measured using Spearman's correlation coefficients between time periods. Internal consistency was measured using Cronbach's alpha. Construct validity was measured by correlating MHQ responses with the Arthritis Impact Measurement Scales 2 (AIMS2). Responsiveness was measured by calculating standardized response means (SRMs) between time periods.ResultsThe MHQ demonstrated good test–retest reliability (r = 0.66, P < 0.001). Cronbach's alpha scores were high for ADL (α = 0.90), function (α = 0.87), aesthetics (α = 0.79), and satisfaction (α = 0.89), indicating redundancy. The MHQ correlated well with AIMS2 responses. Function (r = −0.63), ADL (r = −0.77), work (r = −0.64), pain (r = 0.59), and summary score (r = −0.74) were correlated with the physical domain. Affect was correlated with ADL (r = −0.47), work (r = −0.47), pain (r = 0.48), and summary score (r = −0.53). Responsiveness was excellent among arthroplasty patients in function (SRM 1.42), ADL (SRM 0.89), aesthetics (SRM 1.23), satisfaction (SRM 1.76), and summary score (SRM 1.61).ConclusionThe MHQ is easily administered, reliable, and valid to measure rheumatoid hand function, and can be used to measure outcomes in rheumatic hand disease.
Amorphous Calcium Carbonate is Stabilized in Confinement
Authors: Stephens Christopher J. , Ladden Sophie F. , Meldrum Fiona C. , Christenson Hugo K. 
Published: June 2010

AbstractBiominerals typically form within localized volumes, affording organisms great control over the mineralization process. The influence of such confinement on crystallization is studied here by precipitating CaCO3 within the confines of an annular wedge, formed around the contact point of two crossed half‐cylinders. The cylinders are functionalized with self‐assembled monolayers of mercaptohexadecanoic acid on gold. This configuration enables a systematic study of the effects of confinement since the surface separation increases continuously from zero at the contact point to macroscopic (mm) separations. While oriented rhombohedral calcite crystals form at large (>10 µm) separations, particles with irregular morphologies and partial crystallinity are observed as the surface separation approaches the dimensions of the unconfined crystals (5–10 µm). Further increase in the confinement has a significant effect on the crystallization process with flattened amorphous CaCO3 (ACC) particles being formed at micrometer separations. These ACC particles show remarkable stability when maintained within the wedge but rapidly crystallize on separation of the cylinders. A comparison of bulk and surface free‐energy terms shows that ACC cannot be thermodynamically stable at these large separations, and the stability is attributed to kinetic factors. This study therefore shows that the environment in which minerals form can have a significant effect on their stability and demonstrates that ACC can be stabilized with respect to the crystalline polymorphs of CaCO3 by confinement alone. That ACC was stabilized at such large (micrometer) separations is striking, and demonstrates the versatility of this strategy, and its potential value in biological systems.
Pulmonary and systemic toxicity following exposure to nickel nanoparticles
Authors: Phillips James I. , Green Francis Y. , Davies John C.A. , Murray Jill 
Published: June 2010

AbstractNanoparticles are being used in ever increasing numbers in a range of industrial and medical products. Questions surrounding their potential to cause toxic effects in humans have been raised. Although animal experiments predict that nanoparticles are more toxic than their larger counterparts there are few descriptions in the literature of human exposure. A case described in 1994 has been re‐examined from a pathology perspective. The subject, a 38‐year‐old previously healthy male, inhaled nanoparticles of nickel while spraying nickel onto bushes for turbine bearings using a metal arc process. He died 13 days after being exposed and the cause of death at autopsy was adult respiratory distress syndrome (ARDS). Nickel particles <25 nm in diameter were identified in lung macrophages using transmission electron microscopy. High levels of nickel were measured in his urine and his kidneys showed evidence of acute tubular necrosis. Am. J. Ind. Med. 53:763–767, 2010. © 2010 Wiley‐Liss, Inc.
Feeding ecology of Bornean orangutans (Pongo pygmaeus morio) in Danum Valley, Sabah, Malaysia: a 3‐year record including two mast fruitings
Authors: Kanamori Tomoko , Kuze Noko , Bernard Henry , Malim Titol P. , Kohshima Shiro 
Published: June 2010

AbstractWe observed the diet and activity of Bornean orangutans (Pongo pygmaeus morio) in the primary lowland dipterocarp forests of Danum Valley, Sabah, Malaysia, during 2005–2007, including two mast fruitings. We collected 1,785 hr of focal data on 26 orangutans. We identified 1,466 samples of their food plants and conducted a fallen fruit census to monitor fruit availability in the study area. Their activity budget was 47.2% feeding, 34.4% resting, and 16.9% traveling. Fruits accounted for the largest part (60.9%) of feeding time, especially during mast fruiting periods (64.0–100%), although the percentages of leaves (22.2%) and bark (12.3%) were higher than those reported for P. abelii and P. pygmaeus wurmbii. Although 119 genera and 160 plant species were consumed by focal animals, only 9 genera accounted for more than 3% of feeding time (total: 67.8% for 9 genera). In particular, the focal orangutans fed intensively on Ficus and Spatholobus during most of the study period, especially in periods of fruit shortage. The percentage of fruit feeding changed markedly from 11.7 to 100% across different months of the year, and was positively correlated with the amount of fallen fruit. When fruit feeding and availability decreased, orangutans fed primarily on leaves of Spatholobus and Ficus, and the bark of Spatholobus and dipterocarp. The percentage of time devoted to feeding during mast fruitings, when the orangutans foraged almost exclusively on fruits, was lower than during seasons when the orangutan diet included leaves and bark as well as fruits. Resting increased as feeding decreased in the late stage of each fruiting season, suggesting that the orangutans adopted an energy‐minimizing strategy to survive the periods of fruit shortage by using energy stored during the fruit season. Am. J. Primatol. 72:820–840, 2010. © 2010 Wiley‐Liss, Inc.
Marriage patterns in a Mesoamerican peasant community are biologically adaptive
Authors: Little Bertis B. , Malina Robert M. 
Published: June 2010

AbstractDifferential investment in offspring by parental and progeny gender has been discussed and periodically analyzed for the past 80 years as an evolutionary adaptive strategy. Parental investment theory suggests that parents in poor condition have offspring in poor condition. Conversely, parents in good condition give rise to offspring in good condition. As formalized in the Trivers‐Willard hypothesis (TWH), investment in daughters will be greater under poor conditions while sons receive greater parental investment under good conditions. Condition is ultimately equated to offspring reproductive fitness, with parents apparently using a strategy to maximize their genetic contribution to future generations. Analyses of sex ratio have been used to support parental investment theory and in many instances, though not all, results provide support for TWH. In the present investigation, economic strategies were analyzed in the context of offspring sex ratio and survival to reproductive age in a Zapotec‐speaking community in the Valley of Oaxaca, southern Mexico. Growth status of children, adult stature, and agricultural resources were analyzed as proxies for parental and progeny condition in present and prior generations. Traditional marriage practice in Mesoamerican peasant communities is patrilocal postnuptial residence with investments largely favoring sons. The alternative, practiced by ∼25% of parents, is matrilocal postnuptial residence which is an investment favoring daughters. Results indicated that sex ratio of offspring survival to reproductive age was related to economic strategy and differed significantly between the patrilocal and matrilocal strategies. Variance in sex ratio was affected by condition of parents and significant differences in survival to reproductive age were strongly associated with economic strategy. While the results strongly support TWH, further studies in traditional anthropological populations are needed. Am J Phys Anthropol 143:501–511, 2010. © 2010 Wiley‐Liss, Inc.
Versuche zur Tragfähigkeit von Ankerplatten mit einbetonierten Kopfbolzendübeln in schmalen Stahlbetonstützen
Authors: Fromknecht Stephan , Odenbreit Christoph , Dorka Uwe 
Published: June 2010

AbstractMüssen große Lasten von Stahl‐ in Betonbauteile eingebracht werden, sind Ankerplattendetails mit aufgeschweißten Kopfbolzendübeln oft praktikable Lösungen. Dies gilt auch für die Befestigung von Stahlträgern an Stützen aus Stahlbeton. Hier können die Ankerplatten z. B. bauseits an der Schalung befestigt und mit dem Ortbeton einbetoniert werden.Die Dimensionierung dieser Einbauteile kann, wie auch die Berechnung von nachträglich installierten Befestigungsmitteln, derzeit nach Europäischen Technischen Zulassungen (ETA) erfolgen. Im Unterschied zu nachträglich installierten Befestigungen ist für die Ankerplatte mit einbetonierten Kopfbolzendübeln eine rechnerische Nutzung der Tragfähigkeit der Bewehrung möglich. Allerdings führen die diesbezüglichen Regelungen – im Vergleich zu den in den Versuchen ermittelten Tragfähigkeiten – rechnerisch zu stark eingeschränkten Tragfähigkeiten. Dies beruht einerseits auf der Reduktion der Tragfähigkeit wegen geringer Randabstände und andererseits auf der stark eingeschränkten Nutzbarkeit der Bewehrung.Im folgenden Beitrag werden Versuchsergebnisse vorgestellt, welche den Einfluss der Betondruckfestigkeit, der Verankerungslänge, der Lastexzentrizität sowie der Bewehrungsmenge und ‐position auf das Versagensgeschehen und die Tragfähigkeit zeigen.Results of Experimental Investigations on the Load‐Bearing Capacity of Steel Anchor Plates with in Concrete Encased Headed Studs in Reinforced Narrow Concrete ColumnsAnchor plates with welded shear studs are often used to transfer high loads from steel to reinforced concrete elements. This is for example the case for the fixation of steel beams to reinforced concrete columns. The anchor plates are fixed on site on the formwork and cast in‐place in the concrete.The design is calculated according to European Technical Approvals like the design of post‐installed anchors. In contrast to post‐installed fastenings, the utilisation of the reinforcement of in concrete encased headed studs is theoretically possible. But the regulations of the ETAs lead to great reductions in the analysed load‐bearing capacities compared to the capacities, obtained in tests. These tests have been conducted to investigate the load bearing behaviour and failure modes of anchor plates, especially in narrow reinforced concrete columns.In the following article the results of the experimental investigations are presented, which show the influence of concrete compression strength, shear stud length, load eccentricity as well as amount and position of reinforcement.