bluuebunny/crossref_metadata_2025_split huggingface dataset:
Environmental specialists: their prevalence and their influence on community‐similarity analyses
Authors: Pither Jason , Aarssen Lonnie W. 
Published: February 2005

AbstractRecent research suggests that environmental or habitat specialization among plants may be less common than previously thought. These findings need to be reconciled with interpretations of community‐level similarity analyses that emphasize a strong role for specialization. Here we examine specialization within a taxonomic group that, owing to their widespread use as environmental indicators, should provide ample supportive evidence of specialization: freshwater sediment diatoms. Using an ideal, 239‐lake survey data set that reliably represents the environmental conditions among c. 9500 north‐eastern US lakes (encompassing a c. 405 000 km2 region), we show that only 29 and 14% of 401 species (those occurring in at least two lakes) exhibited narrower pH and total phosphorus niche breadths, respectively, than expected from the random occupation of lakes. These rates increase slightly using more stringent species‐inclusion criteria. Highly significant correlations between compositional and environmental resemblance matrices are shown to reflect a balance between a strong signal generated by the minority specialists, and noise generated by the majority generalists.
Limiting similarity and functional diversity along environmental gradients
Authors: Schwilk Dylan W. , Ackerly David D. 
Published: February 2005

AbstractRecent developments in community models emphasize the importance of incorporating stochastic processes (e.g. ecological drift) in models of niche‐structured community assembly. We constructed a finite, spatially explicit, lottery model to simulate the distribution of species in a one‐dimensional landscape with an underlying gradient in environmental conditions. Our framework combines the potential for ecological drift with environmentally‐mediated competition for space in a heterogeneous environment. We examined the influence of niche breadth, dispersal distances, community size (total number of individuals) and the breadth of the environmental gradient on levels of species and functional trait diversity (i.e. differences in niche optima). Three novel results emerge from this model: (1) niche differences between adjacent species (e.g. limiting similarity) increase in smaller communities, because of the interaction of competitive effects and finite population sizes; (2) immigration from a regional species pool, stochasticity and niche‐assembly generate a bimodal distribution of species residence times (‘transient’ and ‘resident’) under a heterogeneous environment; and (3) the magnitude of environmental heterogeneity has a U‐shaped effect on diversity, because of shifts in species richness of resident vs. transient species. These predictions illustrate the potential importance of stochastic (although not necessarily neutral) processes in community assembly.
Parasites hinder monarch butterfly flight: implications for disease spread in migratory hosts
Authors: Bradley Catherine A. , Altizer Sonia 
Published: February 2005

AbstractMonarch butterflies (Danaus plexippus) are parasitized by the protozoanOphryocystis elektroscirrhathroughout their geographical range. Monarchs inhabiting seasonally fluctuating environments migrate annually, and parasite prevalence is lower among migratory relative to non‐migratory populations. One explanation for this pattern is that long‐distance migration weeds out infected animals, thus reducing parasite prevalence and transmission between generations. In this study we experimentally infected monarchs from a migratory population and recorded their long‐distance flight performance using a tethered flight mill. Results showed that parasitized butterflies exhibited shorter flight distances, slower flight speeds, and lost proportionately more body mass per km flown. Differences between parasitized and unparasitized monarchs were generally not explained by individual variation in wing size, shape, or wing loading, suggesting that poorer flight performance among parasitized hosts was not directly caused by morphological constraints. Effects of parasite infection on powered flight support a role for long‐distance migration in dramatically reducing parasite prevalence in this and other host–pathogen systems.
Proposing a framework to assess Internet usage in university education: an empirical investigation from a student's perspective
Authors: Cheung Waiman , Huang Wayne 
Published: February 2005

AbstractUniversity administrators are continuously investing in Information Technology (IT) to support learning and help deal with educational budget cuts. Instructors are increasingly making their teaching materials available on the Internet. While administrators and instructors would like to make the Internet an effective educational tool, they need to understand what their students’ attitudes towards using it are. Since the use of the Internet in university education is still in its early stages, many issues regarding its use have not been fully addressed. This study was conducted to provide a better understanding of how the Internet is used in university learning from a student's perspective. Our research framework is based on the Theory of Reasoned Action, Technology Acceptance Model, and IT Diffusion Process Model. We use a survey conducted among university students to explore these issues. Research findings provide some useful insights for university administrators and educators.
An investigation into students’ use of a computer‐based social learning space: lessons for facilitating collaborative approaches to learning
Authors: Brett Paul , Nagra Jas 
Published: February 2005

AbstractProvision of computers in universities for self‐study is taken for granted and is seen as a “must have” educational resource, yet it is very expensive to fund. Students report that they use the Internet as their first stop in approaching research tasks. Learning theorists posit the important role of social interaction in contributing to learning. The use of collaborative methodologies such as group work also illustrate the importance, and perceived beneficial role of, learning with others. However, in general, student access to computers for self‐study in UK Higher Education is provided through large rooms furnished with serried ranks of computers, which do not allow or encourage computer‐based collaborative working. This study addresses this mismatch between approaches to learning and the way universities make computers available to learners. The University of Wolverhampton provides a social learning space with 24 computers on four fishbone‐shaped tables, in a room without any restrictions on talking, eating, or drinking. It was provided so as to encourage learners to work collaboratively and to be able to integrate the use of a computer whilst doing so. This paper reports the initial findings of a study into its use, through questionnaires, observational data, and interviews. Has the provision of a computer‐based collaborative learning space positively affected approaches to computer‐based self‐study? The results of this study inform how best Higher Education institutions might provide computer access to learners so as to encourage collaborative working and positively affect student approaches to their learning.
Morphing images: a potential tool for teaching word recognition to children with severe learning difficulties
Authors: Sheehy Kieron 
Published: February 2005

AbstractChildren with severe learning difficulties who fail to begin word recognition can learn to recognise pictures and symbols relatively easily. However, finding an effective means of using pictures to teach word recognition has proved problematic. This research explores the use of morphing software to support the transition from picture to word recognition. Morphing software was used to teach word recognition to a group of eight children who were previously unable to recognise words. At the end of 16 teaching sessions, in a related design, the morphing technique was more effective than a word‐alone approach ( p < 0.05, one‐tailed). These results support the use of techniques such as symbol accentuation (Miller & Miller, 1971) and challenge the concept that the use of pictorial information is inherently detrimental to learning in this context, in comparison to the repeated presentation of words alone. The recent advent of accessible morphing software removes previous barriers to this type of approach. The investigation highlights several useful avenues for future research, in particular, the use of mnemonic elements within morphing teaching methods.
Computers and 2D geometric learning of Turkish fourth and fifth graders
Authors: Olkun Sinan , Altun Arif , Smith Glenn 
Published: February 2005

AbstractThis research investigated the possible impacts of computers on Turkish fourth‐grade students’ geometry scores and further geometric learning. The study used a pretest–intervention–posttest experimental design. Results showed that students who did not have computers at home initially had lower geometry scores. However, these differences were minimised with an appropriate intervention containing computer‐based Tangram puzzles. This suggests that at schools, it seems more effective to integrate mathematical content and technology in a manner that enables students to do playful mathematical discoveries.
Scanning transmission X‐ray microscopy study of microbial calcification
Authors: BENZERARA K. , YOON T. H. , TYLISZCZAK T. , CONSTANTZ B. , SPORMANN A. M. , BROWN G. E. 
Published: February 2005

ABSTRACTCalcium phosphates and calcium carbonates are among the most prevalent minerals involved in microbial fossilization. Characterization of both the organic and mineral components in biomineralized samples is, however, usually difficult at the appropriate spatial resolution (i.e. at the submicrometer scale). Scanning transmission X‐ray microscopy (STXM) was used to measure C K‐edge, P L‐edge, and Ca L‐edge near‐edge X‐ray absorption fine structure (NEXAFS) spectra of some calcium‐containing minerals common in biomineralization processes and to study the experimental biomineralization by the model microorganism, Caulobacter crescentus. We show that the Ca L2,3‐edges for hydroxyapatite, calcite, vaterite, and aragonite are unique and can be used as probes to detect these different mineral phases. Using these results, we showed that C. crescentus cells, when cultured in the presence of high calcium concentration, precipitated carbonate hydroxyapatite. In parallel, we detected proteins, polysaccharides, and nucleic acids in the mineralizing bacteria at the single‐cell scale. Finally, we discussed the utility of STXM for the study of natural fossilized microbial systems.
FIXED‐FREQUENCY RADIO‐WAVE IMAGING OF SUBSURFACE ARCHAEOLOGICAL FEATURES: A MINIMALLY INVASIVE TECHNIQUE FOR STUDYING ARCHAEOLOGICAL SITES*
Authors: SOMERS L. , LINFORD N. , PENN W. , DAVID A. , URRY L. , WALKER R. 
Published: February 2005

In memoriam Tony Clark Sadly, this research marked the last field visit to the test site that the authors were able to share with their colleague Tony Clark. His enthusiasm, experience and encouragement inspired us to complete this project that, to many, must have appeared as grown men at play in a sand pit. A new approach to subsurface exploration has been developed, based on fixed‐frequency radio‐wave illumination from a buried transmitter. Data are collected from a buried, continuous wave source with a phase‐coherent surface‐scanning receiver and recorded in a digital archive from which images of the archaeological features are subsequently produced. An important feature of this approach is the opportunity to separate the data collection and archive functions, which form an uncompromised record of the site, from the more subjective image formation function. This paper reports the results of a feasibility assessment programme and discusses the future application of the method to real archaeological sites.
The Contribution of Foot Problems to Mobility Impairment and Falls in Community‐Dwelling Older People
Authors: Menz Hylton B. , Lord Stephen R. 
Published: February 2005

OBJECTIVES: To investigate the relationship between foot problems, balance, and functional ability in community‐dwelling older people and to determine whether older people with a history of multiple falls exhibit greater foot impairment than those who have not fallen or who have fallen once only.DESIGN: A cross‐sectional, retrospective study.SETTING: Falls and Balance Laboratory, Royal North Shore Hospital, Sydney, Australia.PARTICIPANTS: One hundred thirty‐five community‐dwelling men and women age 75 to 93 (mean age ± standard deviation, 79.8 ± 4.1).MEASURES: Foot problem score; postural sway; coordinated stability; stair ascent and descent; an alternate stepping test; timed 6‐meter walk; and tests of vision, sensation, strength, and reaction time.RESULTS: Eighty‐seven percent of the sample had at least one foot problem. Women had a significantly higher foot problem score than did men. The foot problem score was significantly associated with performance on the coordinated stability test, stair ascent and descent, alternate stepping test, and timed 6‐meter walk. Multiple regression analyses revealed that the foot problem score was a significant independent predictor of performance in the coordinated stability test, stair ascent and descent, and the alternate stepping test. Subjects with a history of multiple falls had a significantly higher foot problem score than did those who had not fallen or who had fallen once only, but the prevalence of individual foot conditions or the presence of foot pain did not differ between these groups.CONCLUSIONS: Foot problems are common in older people and are associated with impaired balance and performance in functional tests. Furthermore, older people with a history of multiple falls have greater foot impairment than non‐ or once‐only fallers. These findings provide further evidence that foot problems are a falls risk factor and suggest that the cumulative effect of multiple foot problems is more important in increasing falls risk than the presence or absence of individual foot conditions.
Real-world ethics and nursing research
Authors: Johnson Martin 
Published: February 2005

In this paper I argue that nursing research is losing its way. There are a number of ways in which this is happening; for example, people are spending much more time writing about methodology than getting on with the research itself and the reporting of discovery. Here, I address the extent to which we are debilitating the research enterprise through what passes as ‘ethics’ and ‘governance’.I will refer to examples from nursing and related research to illustrate the gradual development of greater concern for the well-being of research participants and the prevention of harm. I will go on to illustrate how, in comparison to the search for knowledge in the wider world, the health professions (and in the UK nurses in particular) are making research more difficult to execute than it needs to be. In the development of defensive rules and procedures we have somehow forgotten exactly from what harms we are protecting our patients, students and staff.For those looking for a theoretical background to my views, they are, in essence, consequential, and I hope to show that with a harms and benefits approach we could bring much common sense to the critical appraisal of previous research and the approval and conduct of nursing research now and in the future.
A pilot project to explore the feasibility and potential of a protocol to support district nurses in the assessment of older frail people with type 2 diabetes
Authors: Forbes Angus , Berry Jakki , While Alison , Hitman Graham , Sinclair Alan 
Published: February 2005

A study was undertaken to explore the potential of district nurses assessing older frail people with type 2 diabetes using an explicit schedule in the form of an annual review. A pilot study following pre- and post-test (six-month interval) design explored both process and outcome variables. Twelve older people (mean age 79 years, range 70-86 years) with a diagnosis of type 2 diabetes took part. No statistically significant differences were observed on any of the main outcome measures at the post-test assessment. These findings were explained by insufficient sample size and attrition; a failure to instigate treatment following the identification of specific diabetes-related problems, especially on the part of the GP; and the fact that the sample was reasonably well controlled at the start of the study. The study showed that district nurses were able to administer the annual review satisfactorily but that they found execution of the protocol time-consuming. A great deal of variation was found among respondents, which pointed to different sub-groups of frailty in the older population of people with diabetes, each sub-group having different needs. It was concluded that if district nurses are going to undertake this work, their activity needs to be targeted at the groups of older people most likely to benefit. The current protocol needs further refinement and should be linked to clearer clinical action pathways with a multidisciplinary focus to ensure that the appropriate remedial therapy is instigated.
Macrophage galactose-type C-type lectins as novel markers for alternatively activated macrophages elicited by parasitic infections and allergic airway inflammation
Authors: Raes Geert , Brys Lea , Dahal Bhola K , Brandt Jef , Grooten Johan , Brombacher Frank , Vanham Guido , Noël Wim , Bogaert Pieter , Boonefaes Tom , Kindt Anne , Van den Bergh Rafaël , Leenen Pieter J M , De Baetselier Patrick , Ghassabeh Gholamreza Hassanzadeh 
Published: February 2005

AbstractMolecular markers, especially surface markers associated with type II, cytokine-dependent, alternatively activated macrophages (aaMF), remain scarce. Besides the earlier documented markers, macrophage mannose receptor and arginase 1, we demonstrated recently that murine aaMF are characterized by increased expression of found in inflammatory zone 1 (FIZZ1) and the secretory lectin Ym. We now document that expression of the two members of the mouse macrophage galactose-type C-type lectin gene family (mMGL1 and mMGL2) is induced in diverse populations of aaMF, including peritoneal macrophages elicited during infection with the protozoan Trypanosoma brucei brucei or the Helminth Taenia crassiceps and alveolar macrophages elicited in a mouse model of allergic asthma. In addition, we demonstrate that in vitro, interleukin-4 (IL-4) and IL-13 up-regulate mMGL1 and mMGL2 expression and that in vivo, induction of mMGL1 and mMGL2 is dependent on IL-4 receptor signaling. Moreover, we show that expression of MGL on human monocytes is also up-regulated by IL-4. Hence, macrophage galactose-type C-type lectins represent novel surface markers for murine and human aaMF.
In Vitro Growth and Ovulation of Follicles from Ovaries of Estrogen Receptor (ER)α and ERβ Null Mice Indicate a Role for ERβ in Follicular Maturation
Authors: Emmen Judith M. A. , Couse John F. , Elmore Susan A. , Yates Mariana M. , Kissling Grace E. , Korach Kenneth S. 
Published: February 2005

AbstractBoth estrogen receptor (ER) α and β are expressed within the ovary and lack of either of these receptors affects ovarian function. In this study, the role of ERα and ERβ in folliculogenesis and ovulation was further analyzed. Evaluation of ovarian follicle populations in wild-type and ERβ knockout (βERKO) ovaries revealed reduced late antral growth and ovulatory capacity of βERKO follicles, indicated by reduced numbers of large antral follicles and corpora lutea and increased atresia of large antral follicles. An in vitro culture system was used to study growth, rupture, and luteinization of wild-type, ERα knockout (αERKO) and βERKO ovarian follicles. αERKO follicles exhibited wild-type-like growth and ovulation rates but an increased capacity to synthesize estradiol. In contrast, βERKO follicles showed a significant lack of progression from early antral to large antral stage, decreased estradiol production, and reduced ovulation. Expression patterns of several genes involved in follicle maturation and ovulation were analyzed in follicles grown in vitro. Ar, Pgr, and Has2 mRNA expression levels were the same among the three genotypes. However, βERKO follicles showed reduced expression of Cyp19 mRNA during follicle maturation and reduced Lhcgr and Ptgs2 mRNA expression after human chorionic gonadotropin stimulus. Luteinization occurs normally in αERKO and βERKO follicles, shown by increased progesterone secretion and increased cdkn1b mRNA expression after human chorionic gonadotropin. Collectively, these data indicate that ERβ, but not ERα, plays a direct role in folliculogenesis. ERβ appears to facilitate follicle maturation from the early antral to the preovulatory stage.
Electrochemical synthesis and characterization of polycarbazole
Authors: Macit H. , Sen S. , Saçak M. 
Published: February 2005

AbstractElectroinitiated polymerization of carbazole was achieved in acetonitrile by direct electron transfer via constant potential electrolysis based on anodic peak potentials. The anodic peak potential of carbazole was determined by cyclic voltammetry to be + 1.4V. It has been observed that polymer yield increased with some factors, such as time, monomer concentration, and polymerization potential. Conducting polycarbazole material obtained on a platinum anode electrode was characterized by FT‐IR, TGA, and conductance measurements. The conductivities of samples were measured to be about 10−3–10−4 S/cm by the four‐probe method. Temperature‐dependence of electrical resistance values of polycarbazole between 30°–125°C suggest that it can be used as a thermal sensor. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 894–898, 2005
Antibacterial activity of polymers with norfloxacin moieties against native and norfloxacin‐tolerance‐induced bacteria
Authors: Kim Mal‐Nam , Lim A Hyon , Yoon Jin‐San 
Published: February 2005

AbstractAntimicrobial characteristics were investigated for norfloxacin against 18 bacteria (4 gram‐positive bacteria and 14 gram‐negative bacteria) with the minimum inhibition concentration (MIC) test. Among the bacteria tested, B. cereus, V. fluvialis, and V. parahaemolyticus formed norfloxacin‐tolerant colonies. The release of ultraviolet‐absorbing substances from the cells in contact with norfloxacin was examined for the native bacteria and for the norfloxacin‐tolerance‐induced ones. Norfloxacin was grafted to polypropylene‐graft‐maleic anhydride (MAPP) and poly(styrene‐co‐maleic anhydride) (MAPS) to synthesize polymeric antimicrobial agents. The bioactivity of MAPP–norfloxacin and MAPS–norfloxacin was evaluated and compared with that of neat norfloxacin with the shake flask test and the MIC test. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 936–943, 2005
Uteroferrin: A protein in search of a function
Authors: Roberts R. Michael , Bazer Fuller W. 
Published: February 2005

AbstractUteroferrin, a purple‐colored, iron‐containing acid phosphatase, with many of the properties of a lysosomal hydrolase, transports iron from the mother to the conceptus in pregnant pigs. Uteroferrin, however, is but one member of what may be a broad class of iron‐containing phosphatases with unusual spectral properties which result from a novel type of di‐iron active site. The biological function of uteroferrin is unknown. We argue here that the in vivo function of uteroferrin, despite its undoubted ability to act as a potent acid phosphatase, is that of a transplacental iron transporter.