bluuebunny/crossref_metadata_2025_split huggingface dataset:
Shape‐Memory Stapes Prosthesis for Otosclerosis Surgery
Authors: Knox Glenn W. , Reitan Harlan 
Published: August 2005

AbstractObjectives:The aim of this study was to determine the efficacy of a shape‐memory alloy, Nitinol, as a component of an improved stapes prosthesis.Study Design:Prospective laboratory and clinical study to develop a Nitinol stapes prosthesis.Methods:Various diameters of Nitinol wire and temperature transition variants were analyzed with regard to ease of deformation, response to heating, and strength. The size and geometry of the closed hook was determined by measurement of 50 incus cadaver bones. Several heat sources for activating the shape memory were evaluated, including electrocautery, lasers, and warm water. Trial surgeries were then performed on human temporal bones in the laboratory. The closure characteristics of the Nitinol loop were studied. Magnetic resonance imaging (MRI) testing at 1.5 Tesla was performed to determine safety during MRI studies. Preliminary human subject trials were then instituted.Results:In all cases, a low heat condition was ample to activate the shape memory characteristics of the hook and return it to a closed position after it had been opened. Laser power was generally set well below the power needed for removing bone. The Nitinol loop closed snugly around the incus with application to the top of the hook with a low temperature laser setting. Almost any heat source was effective. MRI testing at 1.5 Tesla showed no movement of the prosthesis. Preliminary results in human subjects showed excellent air‐bone closure. The Nitinol loop holds uniform contact around the incus.Conclusions:The Nitinol piston greatly simplifies the stapedectomy procedure by taking the need for a hand operated instrument out of the surgeon's hands. Because of the nature of the Nitinol wire, it can never over‐crimp. All these characteristics make the prosthesis advantageous for otosclerosis surgery.
The spectral representation of two-point boundary-value problems for third-order linear evolution partial differential equations
Authors: Pelloni Beatrice 
Published: August 2005

We use a spectral transform method to study general boundary-value problems for third-order, linear, evolution partial differential equations with constant coefficients, posed on a finite space domain. We show how this method yields a simple characterization of the discrete spectrum of the associated spatial differential operator, and discuss the obstructions that arise when trying to represent the solution of such a problem as a series of exponential functions.
We first review the theory for second-order two-point boundary-value problems, and present an alternative way to derive the classical series representation, as well as an equivalent integral representation, which generally involves complex contours. We illustrate the advantages of the integral representation by studying in some detail the case where Robin-type boundary conditions are prescribed.

We then consider the third-order case and show that the integral representation is in general
not
equivalent to a discrete series representation, justifying
a posteriori
the failure of some of the classical approaches. We illustrate the third-order case in detail, using the example of the equation
q

t

+
q

xxx

=0 for various types of boundary conditions. In contrast with the second-order case, the qualitative properties of the spectrum of the associated spatial differential operator depend in this case not only on the equation but also on the type of boundary conditions. In particular, the solution appears to admit a series representation only when the prescribed boundary conditions couple the two endpoints of the interval.
Possible new definitions of the kilogram
Authors: Davis R.S 
Published: August 2005

Summary

The kilogram is the unit of mass in the International System. Its definition dates from 1889 and, therefore, predates most of modern physics. The definition simply states that the ‘kilogram’ is the mass of an object known as the international prototype. Thus, we have the extraordinary situation that certain fundamental physical constants (the Planck constant, the Newtonian constant of gravitation, the mass of an electron, the mass of an atom of carbon-12, etc.) are measured in terms of an artefact that was manufactured in the nineteenth century. We begin by describing what is presently known about the long-term stability of artefact standards and how this stability can be experimentally monitored with respect to fundamental constants of physics. Finally, we suggest that present experiments are close to achieving the target uncertainty of the order 10
−8
, although the current incoherence between two classes of experiments is cause for concern.
Population dynamics of harbour seals Phoca vitulina in England: monitoring growth and catastrophic declines
Authors: THOMPSON DAVID , LONERGAN MIKE , DUCK CALLAN 
Published: August 2005

Summary

Harbour seals Phoca vitulina in eastern England were heavily exploited in the 1960s and 1970s, and affected by phocine distemper virus (PDV) epidemics in 1988 and 2002. Information on their historical and current status is required for their management. To maximize the effectiveness of limited population survey effort we need to both estimate and minimize error.
Presented here are data from annual aerial surveys of the population. Sporadic, synoptic surveys in The Wash, England, were used with more frequent counts of subpopulations in the Moray Firth, Scotland, to determine optimum timing of surveys.
We developed models that explicitly account for variability in both observation and population growth processes to show that the proportion of animals observed is much more variable than the annual growth rates. The latter can therefore be treated as constant within each period, and estimated along with the epidemic mortalities during the study and the precision of the survey results.
The Wash population increased at around 3·1% per annum (pa) [95% confidence interval (CI) 2·1–4·1] between 1973 and 1988. It fell by approximately 52% (95% CI 44–59) as a result of the 1988 PDV epidemic, and subsequently increased at 5·7% pa (95% CI 4·8–6·7). These growth rates were below those reported for European mainland populations, but showed no indication of density‐dependent effects.
The recurrence of PDV in 2002 caused approximately 22% mortality (95% CI 9–33), significantly less than the 1988 epidemic and less than half that in European mainland populations in 2002.
Synthesis and applications. Combining sparse, systematic survey data with sporadic counts produced robust estimates of growth rates and epidemic mortality. The results indicate the value of even limited and sporadic survey effort for monitoring populations. The study has highlighted significant differences in both population dynamics and the severity of disease events between English and European harbour seal populations.
Does infectious disease influence the efficacy of marine protected areas? A theoretical framework
Authors: McCALLUM HAMISH , GERBER LEAH , JANI ANDREA 
Published: August 2005

Summary

Marine protected areas are increasingly being recommended as an essential component of the management of exploited marine species, but virtually no attention has been given to the influence of parasites. This may be substantial, as a primary effect of marine reserves is to increase the density of an exploited population within the reserve relative to outside the reserve, which may facilitate parasite transmission.
We used a simple deterministic model of microparasitic infection in a fishery with a reserve to investigate equilibrium yield and parasite prevalence inside and outside the reserve as a function of three control variables: the proportion of habitat inside the reserve, fishing mortality and the rate of interchange between the stock and the reserve.
While our model is generic, we parameterized it with values that may be appropriate to the interaction between abalone and Rickettsia.
The presence of a pathogen does not necessarily decrease yield when a reserve is present, particularly if the rate of movement of adult hosts between stock and reserve is low.
Synthesis and applications. Pathogens have important implications for the design of marine reserves. Our modelling identifies two key considerations. First, ‘fishing out’ a pathogen by reducing the host population density to a level below the threshold for disease maintenance is a potential management strategy that is made more difficult by establishing a reserve. Secondly, the effect of a highly transmissible pathogen without a reserve is to cause a rapid decline in equilibrium yield for efforts beyond those that produce maximum sustainable yield, making the fishery prone to collapse. Introducing a reserve decreases yield in this case, but makes the fishery much more resistant to collapse.
Effects of logging on gastrointestinal parasite infections and infection risk in African primates
Authors: GILLESPIE THOMAS R. , CHAPMAN COLIN A. , GREINER ELLIS C. 
Published: August 2005

SummaryThe impact of habitat disturbance on biodiversity conservation and animal health is poorly understood. Selective logging results in a suite of alterations that may increase infection risk and susceptibility to infection in resident populations.The aim of this study was to improve our understanding of this interplay by examining the effects of logging on infection risk and gastrointestinal parasite infections in three primate species whose populations have responded differently to selective logging in Kibale National Park, Uganda. Populations of redtail guenonsCercopithecus ascaniusare declining in logged forest; red colobusPiliocolobus tephroscelespopulations are in a state of slow recovery; and black‐and‐white colobusColobus guerezapopulations are increasing in logged forest.We collected faecal samples from these three primate species over a period of 5 years in logged and undisturbed forest, to compare parasite infection prevalence and the magnitude of multiple infections. We also analysed canopy and ground vegetation plots to compare environmental contamination with primate parasites in logged and undisturbed forest.The prevalence and richness of gastrointestinal helminth and protozoan parasite infections, and the magnitude of multiple infections were greater for redtail guenons in logged than undisturbed forest, but these parameters did not differ between forest types for either colobine. Data from the canopy and ground vegetation plots revealed that infective stages of two representative generalist primate parasites occurred at higher densities in logged compared with undisturbed forest, signifying a greater infection risk for all primate species in logged forest.Synthesis and applications. This study demonstrates that selective logging can be associated with changes in an important ecological association between hosts and parasites. Our results indicate that anthropogenic habitat change could influence patterns of parasite infection in primates with associated effects on population performance.
Trends in the use of private gardens by wild birds in Great Britain 1995–2002
Authors: CANNON ANDREW R. , CHAMBERLAIN DAN E. , TOMS MIKE P. , HATCHWELL BEN J. , GASTON KEVIN J. 
Published: August 2005

Summary

Wild birds are commonly observed in private residential gardens in Great Britain. However, little is known about how their use of this significant and increasingly important habitat is changing and how such changes relate to their population status.
Trends in the use of private residential gardens by wild birds in Great Britain were investigated using weekly bird records from 18 300 gardens over 8 years.
We showed that the use of this habitat is seasonal and cyclic, with the timing and regularity of its periodicity variable between species.
We evaluated the significance of the underlying trends in the cyclic reporting rates. Eighteen species showed clear trends, the three with the most negative year term parameter estimates being ‘red‐listed’ as high conservation concern.
Examining correlations with national scale survey data suggested that garden reporting rates are related to general population trends in a number of species, including several of conservation importance. Other species exhibit important differences between national and garden trends.
Synthesis and applications. Our analysis demonstrates ecologically meaningful trends and provides novel insights into seasonal cycles of habitat exploitation, using relatively simple and cost‐effectively collected data. This will lead to greater understanding of the relationships between gardens and general bird populations and of the times of year at which garden habitats are most important for birds. We have demonstrated the practicality and productivity of ‘citizen science’ in this context, and provided new information on the status of some birds of conservation concern.
Plant colonization after managed realignment: the relative importance of diaspore dispersal
Authors: WOLTERS MINEKE , GARBUTT ANGUS , BAKKER JAN P. 
Published: August 2005

Summary

Deliberate breaching of sea defences is frequently practised with the aim of restoring salt‐marsh vegetation on previously embanked land. However, experience so far has shown that it may take several years before salt‐marsh vegetation is fully established, and it is possible that limited diaspore dispersal plays a role in this. In order to ascertain whether salt‐marsh development may be constrained by limited diaspore dispersal, we studied the dispersal of salt‐marsh species by tidal water.
From October 2001 to the end of March 2002 a total of 38 species, of which 18 were salt‐marsh species, was trapped in a restoration site and adjacent marsh. Aster tripolium, Limonium vulgare, Puccinellia maritima, Salicornia spp., Spergularia media and Suaeda maritima were the most abundant salt‐marsh species, with more than 3 diaspores m−2 trapped during the study period.
For most species, the number of diaspores trapped was representative of their abundance in nearby vegetation. Hence, despite the potential for long‐distance transport by tidal water, our results indicate a predominantly local dispersal of salt‐marsh species.
Synthesis and applications. For the restoration of salt‐marsh vegetation after de‐embankment, relatively rapid colonization may be expected from pioneer and low‐marsh species, provided they are present in a nearby source area and the restoration site is at the appropriate altitude. The establishment of species absent from the adjacent marsh may be dependent on the presence of birds or humans as the main dispersal agents. Breaching of sea defences should preferably take place before or during September, in order to take advantage of the peak in dispersal of salt‐marsh species in the first year after breaching.
The continuing challenges of testing species distribution models
Authors: VAUGHAN I. P. , ORMEROD S. J. 
Published: August 2005

Summary

Species distribution models could bring manifold benefits across ecology, but require careful testing to prove their reliability and guide users. Shortcomings in testing are often evident, failing to reflect recent methodological developments and changes in the way models are applied. We considered some of the fundamental issues.
Generalizability is a basic requirement for predictive models, describing their capacity to produce accurate predictions with new data, i.e. in real applications beyond model training. Tests of generalizability should be as rigorous as possible: ideally using a large number of independent test sites (≥ 200–300) that represent anticipated applications. Bootstrapping identifies the role of overfitting of the training data in limiting a model's generalizability.
Predictions from most distribution models are continuous variables. Their accuracy may be described by discrimination and calibration components. Discriminatory ability describes how well a model separates occupied from unoccupied sites. It is independent of species prevalence and is readily comparable between models. Rank correlation coefficients, such as the concordance index, are effective measures.
Calibration describes the numerical accuracy of predictions (e.g. whether 40% of sites with predicted probabilities of 0·40 are occupied) but is frequently overlooked in model testing. Poor calibration could mislead any conservation efforts utilizing models to estimate the ‘value’ of different sites for a given species. Effective assessments can be made using smoothed calibration plots.
The effects of species prevalence on nominal presence–absence predictions are well known. The currently preferred accuracy measure, Cohen's κ, has weaknesses. We argue that mutual information measures, based in information theory, may be more appropriate.
Synthesis and applications. Model evaluation must be informative and should ideally: (i) define generalizability in detail; (ii) separate the discrimination and calibration components of accuracy and test both; (iii) adopt assessment techniques that permit more valid intermodel comparisons; (iv) avoid nominal presence–absence evaluation where possible and consider information‐theoretic measures; and (v) utilize the full range of techniques to help diagnose the causes of prediction problems. Few modellers in applied ecology and conservation biology satisfy these needs, making it difficult for others to evaluate models and identify potential misuses. The problems are real, and if uncorrected will damage conservation efforts through the inaccurate assessment of distribution and habitat preferences of important organisms.
Optimizing dispersal study design by Monte Carlo simulation
Authors: SKARPAAS OLAV , SHEA KATRIONA , BULLOCK JAMES M. 
Published: August 2005

SummaryThe distribution of dispersal distances (the dispersal kernel) is a major determinant of spatial population dynamics, yet little is known about the shape of the dispersal kernel for most species. This is partly because of the relative difficulty of measuring dispersal, exacerbated by a lack of standardized protocols. We suggest that this problem can be addressed by using modelling approaches to aid the design of studies to quantify dispersal.In this study we present such an approach by optimizing seed trap sampling design using stochastic simulations. A number of alternative sampling designs (random placements, grid arrays, transects, sectors and annuli arrangements) for a point source were tested against a common kernel to assess the best methods for estimating the dispersal kernel.For a given source strength and total trap area, transects and sectors of traps usually provided better data for kernel estimation than random placement, grid arrays and annuli. Kernel estimation was improved by increasing the source strength (the number of dispersing propagules) and the trap area, as expected.When the ‘true’ kernel was unknown, transects were slightly better for identifying the thin‐tailed exponential distribution, whereas sectors were better for detecting the fat‐tailed half‐Cauchy.In the case of anisotropic dispersal (here, dispersal biased in one direction), annuli and grid arrays performed better than transects and sectors when the anisotropy was unknown. However, when the anisotropy was anticipated, and the trap arrangements were adjusted accordingly, transects and sectors were better. This was true regardless of source strength and total trap area.Synthesis and applications. This study presents a simulation approach to the design of dispersal experiments. While the general results of our simulations can be used by those designing field studies for plant point sources, the simulation approach itself can be modified for a wide range of organisms, dispersal mechanisms and dispersal measurement approaches. Thus, the approach presented here facilitates improvements of dispersal study designs, which in turn will increase the precision of dispersal kernel estimates and predictions of spatial population dynamics, including modelling of rates of spread or metapopulations. This is invaluable in a range of ecological applications, such as the management of rare or invasive species, predicting species’ response to climate change, or planning species reintroductions.
Integrating published data and citizen science to describe bird diversity across a landscape
Authors: LEPCZYK CHRISTOPHER A. 
Published: August 2005

Summary

Knowledge of species diversity across a landscape is essential for answering ecological questions and developing conservation and management goals and protocols. However, data on species occurrence are often limited, with the consequence that species lists are incomplete.
As a means to develop a complete species occurrence list for an urbanizing landscape in south‐eastern Michigan, USA, all bird species accounts from four public and private organizations were integrated, and all officially documented rare birds added. A citizen science approach was then used to develop an independent species list from c. 1700 landowner surveys.
The specific goals of the research were to: (i) develop a complete list of species occurrence across a landscape; (ii) ascertain what percentage of the total species pool landowners could collectively identify; (iii) identify species that had not been noted in the census data sets but could be corroborated; (iv) compare the percentage overlap among different bird censuses; and (v) assess the potential value of casual (i.e. citizen science) records to bird distribution studies.
The resulting list comprised 318 individual bird species, which was 8·5% greater than any of the individual lists. Landowners identified 171 bird species (c. 54%) and had > 50% overlap with all existing databases. In addition, landowners identified 10 species noted only in a single database of rare or vagrant species. The percentage overlap of species across the five different lists ranged from 35% to 66%, with the differences stemming largely from different protocols. Subsetting the data for one county within the landscape reduced the unique species to 294, which was approximately equivalent to the existing county species list.
Synthesis and applications. The findings highlight the value of surveying private landowners as a means of detecting species presence/absence in numerous inaccessible locations, and the important role landowners can play in providing species occurrence information. Similarly, the results indicate the need to use multiple data sources for establishing a list of potential species occurrence for the conservation and management of biological resources.