bluuebunny/crossref_metadata_2025 huggingface dataset:
The signature of long-standing balancing selection at the human defensin β-1 promoter
Authors: Cagliani Rachele , Fumagalli Matteo , Riva Stefania , Pozzoli Uberto , Comi Giacomo P , Menozzi Giorgia , Bresolin Nereo , Sironi Manuela
Published: September 2008

Background

Defensins, small endogenous peptides with antimicrobial activity, are pivotal components of the innate immune response. A large cluster of defensin genes is located on human chromosome 8p; among them the beta defensin 1 (DEFB1) promoterhas been extensively studied since discovery that specific polymorphisms and haplotypes associate with asthma and atopy, susceptibility to severe sepsis, as well as HIV and Candida infection predisposition.

Results

Here, we characterize the sequence variation and haplotype structure of the DEFB1 promoter region in six human populations. In all of them, we observed high levels of nucleotide variation, an excess of intermediate-frequency alleles, reduced population differentiation and a genealogy with common haplotypes separated by deep branches. Indeed, a significant departure from the expectation of evolutionary neutrality was observed in all populations and the possibility that this is due to demographic history alone was ruled out. Also, we verified that the selection signature is restricted to the promoter region and not due to a linked balanced polymorphism. A phylogeny-based estimation indicated that the two major haplotype clades separated around 4.5 million years ago, approximately the time when the human and chimpanzee lineages split.

Conclusion

Altogether, these features represent strong molecular signatures of long-term balancing selection, a process that is thought to be extremely rare outside major histocompatibility complex genes. Our data indicate that the DEFB1 promoter region carries functional variants and support previous hypotheses whereby alleles predisposing to atopic disorders are widespread in modern societies because they conferred resistance to pathogens in ancient settings.
Psychological therapies provision: views from primary care
Authors: Ward Anne , Polizzi Giovanni , Milovanovic Miomir
Published: September 2008

Aims and Method

Recent National Health Service (NHS) policy and guidelines support the increased provision of psychological therapies. As secondary care providers of psychological therapies, we carried out a questionnaire study of how our services were perceived by local general practitioners (GPs). All GPs in the borough of Southwark were included.

Results

General practitioners value secondary care psychotherapeutic input across a spectrum of complex diagnostic groups and are interested in further training/education. They also consistently complain about long waiting times and confusion about accessing the various services.

Clinical Implications

With increasing interest in and willingness to fund the delivery of psychological therapies, there is the potential for working more effectively across the primary–secondary care divide. However, improved communication between primary and secondary care is essential if the increased commitment at government level is to be translated into a locally effective service.
Racial Disparities in Access to Long-Term Care: The Illusive Pursuit of Equity
Authors: Smith David Barton , Feng Zhanlian , Fennell Mary L. , Zinn Jacqueline , Mor Vincent
Published: September 2008

While nursing homes were insulated from civil-rights enforcement at the time of the implementation of the Medicare program and lagged behind other parts of the health sector in providing comparable access to minorities, they are the only providers for which current reporting requirements make it possible to fully assess racial disparities in use and quality of care. We find that African Americans' use of nursing homes in 2000 in the United States was 14 percent higher than Caucasians' use. The largest relative African American use of nursing homes in 2000 took place in the South and West. Average nursing-home case-mix acuity for African Americans and Caucasians were essentially identical, suggesting that shifts in payment incentives have eliminated the selective admission of easy-care private-pay (predominantly Caucasian) patients and helped fuel the growth of private pay home care and assisted living for this segment of the population. While these shifts in incentives helped increase the use of nursing homes by African Americans, a high degree of segregation and disparity in the quality of the nursing homes used by African Americans persists. Parity in use is an illusive benchmark for measuring progress in assuring equity in treatment.
Receipt of Preventive Dental Care among Special-Needs Children Enrolled in Medicaid: A Crisis in Need of Attention
Authors: Mitchell Jean M. , Gaskin Darrell J.
Published: September 2008

Although not widely recognized, tooth decay is the most common childhood chronic disease among children ages five to seventeen. Despite higher rates of dental caries and greater needs, low-income minority children enrolled in Medicaid are more likely to go untreated relative to their higher income counterparts. No research has examined this issue for children with special needs. We analyzed Medicaid enrollment and claims data for special-needs children enrolled in the District of Columbia Medicaid program to evaluate receipt of recommended preventive dental care. Use of preventive dental care is abysmally low and has declined over time. Enrollment in managed care rather than fee for service improves the likelihood that special-needs children receive recommended preventive dental services, whereas residing farther from the Metro is an impediment to receipt of dental care.
Promoting a “Good Death”: Determinants of Pain-Management Policies in the United States
Authors: Imhof Sara L. , Kaskie Brian
Published: September 2008

Many Americans do not experience a good death. The inadequate treatment of pain at the end of life has been associated with a lack of supportive public policies more than a lack of evidence-based clinical practices or organizational efforts. Given a widespread lack of understanding about pain policies, we examine the critical role played by state medical boards in developing pain policies and then apply event history analysis to identify the variables most critical to the formation of these policies. We develop an integrated model and evaluate the adoption of eight different types of pain policies. The analytic models incorporate fifteen years of observational data and test the impact of contextual, political, extrinsic, and institutional variables. They reveal that the presence of legal counselors on state medical boards has consistently increased the likelihood that state boards adopt policies associated with progressive pain management. Further, policy has been negatively influenced by historical activity: boards that previously adopted one pain policy have been less likely to subsequently adopt additional pain policies. This work illuminates mechanisms behind state pain-policy adoption and provides valuable information for advocates who seek to improve pain-management policy and reduce the amount of pain at the end of life.
Health Care Financing Reforms in Germany: The Case for Rethinking the Evolutionary Approach to Reforms
Authors: Carrera Percivil M. , Siemens Karen K. , Bridges John
Published: September 2008

Health care reform has been a perpetual issue in German politics since reunification. Reform initially focused on restructuring the health care system of the former East Germany. It has subsequently focused on questioning whether the financing of the German social health insurance (SHI) system is sustainable, in light of economic malaise that characterized the 1990s and heightened global competition. In this article, we document twelve significant attempts to reform health care financing in Germany and critically appraise them according to the principles of solidarity and subsidiarity on which SHI systems were built. While the reforms in the aggregate offered the prospect of addressing the challenges faced by the system, the modest results of the reforms and remaining deficiencies of the system underscore the limitations of the evolutionary approach to reforms. This suggests that reformers should consider a more revolutionary approach.
A high-tech infusion for science
Authors: Griekspoor Alex
Published: September 2008

Alex Griekspoor’s PhD in cell biology led to an interesting and unexpected twist that resulted in a unique career in computer programming. Now he creates new computer technology using his blend of research knowledge and computer prowess. After bringing the science community programs like Papers and 4Peaks, Dr Griekspoor started his own software company, mekentosj.com and the future looks bright.
Crack growth of medical-grade silicone using pure shear tests
Authors: Leslie L , Kukureka S , Shepherd D E T
Published: September 2008

Silicone elastomers are commonly used in the manufacture of single-piece joint replacement implants for the finger joints. However, the survivorship of these implants can be poor, with failure typically occurring from fracture of the stems. The aim of this paper was to investigate the crack growth of medical-grade silicone using pure shear tests. Two medical-grade silicones (C6-180 and Med82-5010-80) were tested. Each sample had a 20 mm crack introduced and was subjected to a sinusoidally varying tensile strain, with a minimum of 0 per cent and a maximum in the range 10 to 77 per cent. Testing was undertaken at a frequency of 10 Hz. At various times during testing, the testing machine was stopped, the number of cycles completed was noted, and the crack length measured. Graphs of crack length against number of cycles were plotted, as well as the crack growth rate against tearing energy. The results show that Med82-5010-80 is more crack resistant than C6-180. Graphs of crack growth rate against tearing energy can be used to predict the failure of these medical-grade elastomers.
Partitioning of Servers in Queueing Systems During Rush Hour
Authors: Hu Bin , Benjaafar Saif
Published: September 2008

This paper is motivated by two phenomena observed in many queueing systems in practice. The first is the partitioning of server capacity among different customers based on their service time requirements. The second is rush hour demand where a large number of customers arrive over a short period of time followed by few or no arrivals for an extended period thereafter. We study a system with multiple parallel servers and multiple customer classes. The servers can be partitioned into server groups, each dedicated to a single customer class. The system operates under a rush hour regime with a large number of customers arriving at the beginning of the rush hour period. We show that this allows us to reduce the problem to one that is deterministic and for which closed-form solutions can be obtained. We compare the performance of the system with and without server partitioning during rush hour and address three basic questions. (1) Is partitioning beneficial to the system? (2) Is it equally beneficial to all customer classes? (3) If it is implemented, what is an optimal partition? We evaluate the applicability of our results to systems where customers arrive over time using (1) deterministic fluid models and (2) simulation models for systems with stochastic interarrival times.
Dynamic Capacity Expansion for a Service Firm with Capacity Deterioration and Supply Uncertainty
Authors: Chao Xiuli , Chen Hong , Zheng Shaohui
Published: September 2008

Motivated by the challenges faced by the telecom industry during the past decade, in this paper we study a dynamic capacity expansion problem for service firms. There is a random demand for the firm's capacity in each period: the demand in excess of the capacity is lost, and revenue is generated for the fulfilled demand. At the beginning of each period, the firm might increase its capacity through purchasing equipment for immediate delivery, which is constrained by a random supply limit, or it might sign a future contract for equipment delivery in the following period. We assume that the firm's capacity might partially become obsolete due to natural deterioration or technology innovation. We aim at characterizing optimal capacity expansion strategies and comparing the profit functions as well as the optimal control policies of different options. Specifically, we show that the optimal capacity expansion policy for the current period is determined by a base-stock policy. Compared with the case where no future contracts are available, the optimal control parameters of capacity expansion are always smaller. We further show that when the obsolescence rate is deterministic, the optimal policy for capacity expansion through future contracts is also a base-stock type. The results are extended to the cases with stochastically dependent capacity supply limits and stochastically dependent demand processes, which establish the robustness of the optimal policy in various market conditions.
Dynamic Control of a Make-to-Order, Parallel-Server System with Cancellations
Authors: Rubino Melanie , Ata Barış
Published: September 2008

Motivated by make-to-order production systems, we consider a dynamic control problem for a multiclass, parallel-server queueing system. The production system serves multiple classes of customers who require rigid due-date lead times and may cancel their order subject to a cancellation penalty. To meet the due-date constraints, a system manager may outsource orders when the backlog of work is judged excessive, thereby incurring outsourcing costs. The system manager strives to minimize long-run average costs by dynamically making outsourcing and resource allocation decisions. Under heavy-traffic conditions, the scheduling problem is approximated by a Brownian control problem. Interpreting the solution of the Brownian control problem in the context of the original queueing system, a nongreedy outsourcing and resource allocation policy is proposed. A simulation experiment is performed to demonstrate the effectiveness of this policy.
Surgical management with mitral valve replacement in young infants with congenital mitral valve diseases and complete atrioventricular septal defect
Authors: Hartyánszky István , Mihályi Sándor , Bodor Gábor
Published: September 2008

A szerzők
célja
volt csecsemőkorban vizsgálni a veleszületett mitralisbillentyű-szűkület és -elégtelenség sebészi kezelését, valamint a komplett atrioventricularis septumdefektus (CAVD) teljes korrekciója során a mitralis billentyű kialakításának, pótlásának lehetőségét.
Betegek:
2001 és 2007 között 82, egy évnél fiatalabb csecsemőn a korrekciós műtétet követően 7 betegben (5 hét–7 hónap, 3,5–5 kg) mitralis (bileaflet) műbillentyű korai beültetése vált szükségessé. A két műtét közti idő 0–7 nap, de a legkisebb csecsemőnél intenzív kezelés mellett 38 napot kellett várni az annulus feltágulására, hogy a legkisebb műbillentyű beültethető lehessen. A műbillentyűk típusa: 16 mm-es Carbomedics 2, 16 mm-es ATS 3, 17 mm-es Sorin 1, 19 mm-es Sorin 1. Congenitalis mitralis stenosis, illetve insufficientia miatt 2-2 csecsemőbe kellett 16 mm-es ATS billentyűt beültetni.
Eredmény:
30 napos mortalitás 0. Egy-egy csecsemő a 46., illetve a 71. posztoperatív napon szepszisben meghalt. 1–6 (átlag 3) éves utánkövetés: 1 betegben kellett pannust eltávolítani, a betegek panaszmentesek. Az antikoaguláns terápia helyes beállítása nehézséget jelentett.
Összefoglalás:
Congenitalis mitralis stenosis és elégtelenség, valamint a CAVD sebészi korrekciója már kis súlyú újszülötteken is sikerrel elvégezhető. Kedvezőtlen anatómiai helyzetben a mitralis billentyű kialakításának lehetetlensége esetén csak a műbillentyű-beültetés a megoldás. Ez kilátástalannak tűnő helyzetben (kis mitralis annulus) is elvégezhető jó eredménnyel. (Tudomásunk szerint 3500 g súlyú betegünk a legkisebb, sikeresen operált eset.) Ezt igazolják eseteink korai és középtávú eredményei.
Conservative treatment of benign prostatic hyperplasia
Authors: Romics Imre
Published: September 2008

A szerző összefoglalja a benignus prostata-hyperplasiában jelenleg alkalmazott gyógyszereket. A növényi kivonatokkal szerzett tapasztalatok két évtizedes múltra tekintenek vissza, alkalmazásuk a benignus prostata-hyperplasia iniciális fázisában javasolt. A hormonális hatású 5-alfa-reduktáz finasterid jelentős, bár csak több év-hónap alatt kialakuló prostatavolumen-redukció a vizelési zavarok mechanikus komponensét befolyásolja kedvezően. Indikációja főleg a 40 g feletti prostatavolumen esetén áll fenn. Az alfa-receptor-gátlók a hólyagnyakra ható, rövid terápiás idejű relaxáns hatásokkal a prostata-hyperplasia dinamikus komponensére hatnak, alkalmazásuk indokolt minden benignus prostata-hyperplasia esetében, függetlenül a prostatavolumentől. Több-kevesebb hypotoniás mellékhatással számolni kell. Az utóbbi időben az 5-foszfodiészteráz-gátlók kedvező hatását is leírták, illetve az is nyilvánvalóvá vált, hogy az alfa-blokkolókkal kezelt beteg szexuális aktivitása is fokozódik.
Rapid cycle-dependent softening of equal channel angularly pressed Sn–Ag–Cu alloy
Authors: Zhu Q.S. , Wang Z.G. , Zeng Q.L. , Wu S.D. , Shang J.K.
Published: September 2008

Cyclic stress–strain response of an equal channel angularly pressed Sn-3.8Ag-0.7Cu alloy was investigated to seek a mechanistic understanding of cyclic softening in Sn-rich alloys. The equal channel angular pressing (ECAP) was applied to modify the microstructure of the solder alloy by breaking up the needlelike Ag3Sn intermetallic phase into fine granules and by reducing the large β-Sn dendrites into smaller and equiaxed grains. The extruded alloys were subjected to strain-controlled fatigue test at various strain amplitudes. It was found that the extruded alloy exhibited a sharp decrease of the stress amplitude within the initial few cycles compared with the as-cast alloy. After only a few cycles, the alloy suffered from noticeable surface damage. In situ scanning electron microscopy observations of the cyclic bending specimens revealed an approximately logarithmic relationship between crack density and the number of cycles. A theoretical model of microcrack accumulation was constructed to explain the rapid cyclic softening behavior. The predicted results, based on the model, agreed well with the experimental data and indicated that the rapid softening had resulted from an increased tendency for grain boundary cracking in the ECAPed microstructure due to the increase in the grain boundary area per unit volume and the reduced resistance of Ag3Sn to grain boundary sliding.
High-temperature electrical behavior of nanocrystalline and microcrystalline diamond films
Authors: Govindaraju N. , Das D. , Singh R.N. , Kosel P.B.
Published: September 2008

Chemical vapor deposition of diamond has opened up new applications in microelectronics, microelectromechanical systems (MEMS), and coating technologies. This paper compares and contrasts the high-temperature electrical behavior of microcrystalline versus nanocrystalline diamond films. Through-thickness current–voltage characteristics between room temperature and 823 K are presented for a series of films synthesized with different gas phase concentrations of nitrogen and argon. One set of samples was characterized by measurements between room temperature and 823 K and a second set by two-step thermal cycling from room temperature to 573 and 823 K. It was found that with increasing nitrogen concentration (up to 0.1% N2), the resistivity slightly increased followed by a decrease at higher concentrations. Activation energies and barrier heights were in general lower for the more defective films. These results in conjunction with material characterization indicated that more defective diamond films were synthesized at higher nitrogen concentrations in the gas phase.
Effects of rare earth on the structure and properties of Mg–6Zn–5Al–4Gd–1RE (RE = Ce or Y) alloys
Authors: Xiao Wenlong , Jia Shusheng , Wang Jianli , Yang Jie , Wang Lidong , Wang Limin
Published: September 2008

The microstructures and mechanical properties of Mg–6Zn–5Al–4Gd–1RE (RE = Ce or Y) alloys were investigated. The addition of Ce or Y obviously refines the grain size for the Mg–6Zn–5Al–4Gd-based alloy, while the Y element has a better refining effect. The Ce and Y show different grain-refining mechanisms: Ce addition mostly promotes the growth of secondary dendrite, while Y addition mainly increases the heterogeneous nucleation sites. The hardness-versus-aging time curves indicate that all the alloys have excellent aging-hardening behavior, but the response to maximum hardness was delayed by the Ce or Y addition. The microstructure observation of the peak-aged alloys indicated a large number of nanocrystalline τ-Mg32(Al, Zn)49 precipitates in the matrix. The Y addition is beneficial to improve the mechanical properties, and the alloy has optimal values. However, the Ce addition decreases the ultimate tensile strength and elongation of the alloy due to formation of a lot of shrinkage porosities.
Characterizing displays by their temporal aperture: A theoretical framework
Authors: van Heesch F. H. , Klompenhouwer M. A. , de Haan G.
Published: September 2008

Abstract—The spatio‐temporal aperture and sample rate of a video display determines both the static and dynamic resolution of the video signal that is rendered. The dynamic display characteristics like the visibility of large‐area flicker, motion judder, and motion blur can be derived from the frame rate and the temporal extent of the pixel aperture (i.e., the temporal aperture). For example, liquid‐crystal displays (LCDs) have an aperture that is relatively small in the spatial dimension and wide in the temporal domain. Consequently, moving objects displayed on an LCD suffer from motion blur. Especially in TV applications, the temporal dimension has a large impact on the overall picture quality. The temporal aperture, together with the frame rate, is shown to predict the amount of perceived large‐area flicker, motion judder, and motion blur and also the performance of motion‐blur reduction algorithms for LCDs. From this analysis it is further determined how to obtain the optimal temporal aperture of a television display, for which not only properties of the human visual system (HVS), but also the properties of the video signal have to be taken into account.
A geometrical approach for inverting display color‐characterization models
Authors: Thomas Jean‐Baptiste , Colantoni Philippe , Hardeberg Jon Y. , Foucherot Ire`ne , Gouton Pierre
Published: September 2008

Abstract—Some display color‐characterization models are not easily inverted. This work proposes ways to build geometrical inverse models given any forward color‐characterization model. The main contribution is to propose and analyze several methods to optimize the 3‐D geometrical structure of an inverse color‐characterization model directly based on the forward model. Both the amount of data and their distribution in color space is especially focused on. Several optimization criteria, related either to an evaluation data set or to the geometrical structure itself, are considered. A practical case with several display devices, combining the different methods proposed in the article, are considered and analyzed.
3‐D crosstalk and luminance uniformity from angular luminance profiles of multiview autostereoscopic 3‐D displays
Authors: Salmimaa Marja , Järvenpää Toni
Published: September 2008

Abstract— Autostereoscopic 3‐D display technologies enable a more immersive media experience by adding real depth to the visual content. However, the method used for the creation of a sensation of depth or stereo illusion contains several display design and content‐related issues that need to be carefully considered to maintain sufficient image quality. Conventionally, methods used for 3‐D image‐quality evaluations have been based on subjective testing. Optical measurements, in addition to subjective testing, can be used as an efficient tool for 3‐D display characterization. Objective characterization methods for autostereoscopic displays have been developed. How parameters affecting stereo image quality can be defined and measured, and how their effect on the stereo image quality can be evaluated have been investigated. Developed characterization methods are based on empirically gathered data. In this paper, previously presented methodology for two‐view displays is extended to cover autostereoscopic multiview displays. A distinction between displays where the change in content occurs in clear steps when the user moves in front of the display, and displays where the apparent movement of the objects is more continuous as a function of the head movement is made. Definitions for 3‐D luminance and luminance uniformity, which are equally important, as well as 3‐D crosstalk, which is the dominant factor in the evaluations of the perceived 3‐D image quality, is focused upon.
The effects of glossy screens on the acceptance of flat‐panel displays
Authors: Brunnström Kjell , Josefsson Katarina , Andrén Börje
Published: September 2008

Abstract— The TCO requirements provide well‐known and recognized quality labels for displays. For these requirements to remain useful, they must continuously be reviewed and updated when necessary. The study described here was performed in response to the market trend of designing flat‐panel displays and notebooks with glare panels. The purpose of this study was to investigate subjective responses to display screens of different gloss levels for office workers working on different tasks under normal office‐lighting conditions. The study consisted of three parts, one where the users should set an acceptable reflex level, one where the user should rate their disturbance on a category scale, and one where the visual acuity of the users were investigated whether they were affected by glare or not. The results show that increasing gloss and increasing luminance levels had negative effects on the acceptance and the disturbance of reflexes. There were statistically significant differences in the acceptance and the disturbance levels between screens with low gloss and screens with high gloss, which suggests that screens with the highest gloss levels should be avoided. The study did not show an effect on the performance based on acuity testing.
Analysis of the dependence of optical response time of liquid‐crystal displays on the viewing direction
Authors: Hong Hyung Ki , Yoon JaeKyeong , Lim Moojong
Published: September 2008

Abstract— The optical response time of liquid‐crystal displays (LCDs) has recently been observed to be dependent on the viewing direction. For the vertically aligned LC mode, response time increased as the viewing angle increased when the final state is the zero gray level of the minimum luminance. This change in response time is analyzed to relate to the deformation of the normalized luminance curve of LCDs for different viewing directions. The dependency trends of the optical response time for the oblique direction can be estimated from the temporal luminance measurement data along the normal direction and the normalized luminance curve for oblique viewing directions.
Fast‐response liquid‐crystal displays using crossed fringe fields
Authors: Li Yan , Ge Zhibing , Lu Ruibo , Jiao Meizi , Wu Shin‐Tson
Published: September 2008

Abstract— A fast‐response and wide‐view liquid‐crystal display (LCD) using the crossed fringe‐field‐switching (CFFS) mode is proposed, where the fringe‐field electrodes exist on both the top and bottom substrates. The bottom fringe field is used to turn on the LC directors and the top fringe field is used to assist in the LC decay process. The decay time is reduced by ∼2× compared to that of the conventional FFS mode between the full bright and dark states, and more than a 2× improvement is obtained for other gray‐scale transitions. This CFFS mode also preserves the wide‐view characteristics as the conventional FFS mode. Its applications to LCD TVs and monitors for reducing image blur are addressed.
Comparisons of motion‐blur assessment strategies for newly emergent LCD and backlight driving technologies
Authors: Feng Xiao‐fan , Pan Hao , Daly Scott
Published: September 2008

Abstract— Compared to the conventional cathode‐ray‐tube TV, the conventional liquid‐crystal TV has the shortcoming of motion blur. Motion blur can be characterized by the motion‐picture response‐time metric (MPRT). The MPRT of a display can be measured directly using a commercial MPRT instrument, but it is expensive in comparison with a photodiode that is used in temporal‐response (temporal luminance transition) measurements. An alternative approach is to determine the motion blur indirectly via the temporal point‐spread function (PSF), which does not need an accurate tracking mechanism as required for the direct “spatial” measurement techniques. In this paper, the measured motion blur is compared by using both the spatial‐tracking‐camera approach and the temporal‐response approach at various backlight flashing widths. In comparison to other motion‐blur studies, this work has two unique advantages: (1) both spatial and temporal information was measured simultaneously and (2) several temporal apertures of the display were used to represent different temporal PSFs. This study shows that the temporal method is an attractive alternative for the MPRT instrument to characterize the LCD's temporal performance.
Motion‐blur evaluation: A comparison of approaches
Authors: Becker Michael E.
Published: September 2008

Abstract— In this paper, the results obtained from two independent evaluations of motion‐blur effects with respect to the agreement between the two different approaches used, imaging and non‐imaging, are analyzed. The measurements have been carried out in different laboratories by different operators without the prior intention of a subsequent analysis as presented here. The resulting data is analyzed to quantify the repeatability of each instrument and, in a second step, the comparability of results from the two approaches is investigated. The imaging approach used in these experiments is based on a stationary high‐speed camera with temporal oversampling and numerical image‐data processing to obtain the intensity distribution on the retina of an observer under the condition of smooth pursuit eye tracking. Results from that approach are compared to results obtained from the evaluation of step responses acquired with optical transient recorders by frame‐period convolution. Measurements are carried out with a first LCD monitor with test patterns of both contrast polarities, with three velocities of translation, and four levels of gray. A second object of measurement is used for investigation of the effect of operator intervention in the process of evaluation of the imaging approach, especially on the determination of the reference levels that are needed for evaluation of the normalized blurred edge (NBE). Possible sources of uncertainties are identified for all approaches and instruments. Based on the analysis of that data, the practicability of step‐response‐based evaluations of the “blurred edge width/time” compared to the results obtained using the high‐speed imaging approach, as long as there is no motion‐dependent image processing, are confirmed.
A national risk assessment for intersex in fish arising from steroid estrogens
Authors: Williams Richard J. , Keller Virginie D. J. , Johnson Andrew C. , Young Andrew R. , Holmes Matthew G. R. , Wells Claire , Gross-Sorokin Melanie , Benstead Rachel
Published: September 2008

The occurrence of intersex fish is widespread in the rivers of England and Wales. The extent of intersex in fish populations is believed to be strongly linked to their exposure to steroid estrogens. The present study presents, to our knowledge, the first national, catchment-based risk assessment for steroid estrogens in the world. A graphical information system–based model predicted the concentrations of estradiol (E2), estrone, and ethinylestradiol, which were combined and compared with known biological effect levels to predict the risk of endocrine disruption for 10,313 individual river reaches (21,452 km) receiving effluent from more than 2,000 sewage treatment plants serving more than 29 million people. The large scale of this assessment underlines the usefulness of computer-based risk assessment methods. Overall, 39% of the modeled reaches (all percentages are in terms of the total river length modeled) in England and Wales were predicted to be not at risk from endocrine disruption (mean concentrations, <1 ng/L E2 equivalents). A large range existed in the percentage of river reaches at risk in the various regions, from 5% in Wales to 67% in the Thames catchment. Important factors influencing this proportion are the population density, particularly their location, and the available dilution. A very small proportion of reaches (∼1–3%) were predicted to be at high risk (>10 ng/L E2 equivalents). Many of these high-risk reaches, however, were ditches, which were composed almost entirely of sewage effluent. The model could be applied equally well to any other chemical of concern emanating from the human population that would be impractical to assess by measurement.
“ARE THE RUSSIANS INVOLVED, SIR?”: THE BRITISH DIMENSION OF DR. STRANGELOVE
Authors: Morrison Steven
Published: September 2008

Filmed in Shepperton by a director from New York, shaped by a novel by a British author at its inception and inﬂuenced by the work of a British cast and crew during its production, Stanley Kubrick’s Dr. Strangelove is explored in this essay as a British–American hybrid. Kubrick’s film was informed throughout the period of its creation by the differences in political and cultural attitudes toward the nuclear threat that existed between the US and the UK during the Cold War. This allowed the film to act as a reﬂection of the shift in the general understanding of the nuclear dilemma between 1958 and 1964 on both sides of the Atlantic – a movement from apparently inescapable anxiety toward a form of release and gleeful resignation.
Immunomodulatory Effects of Feed-BorneFusariumMycotoxins in Chickens Infected with Coccidia
Authors: Girgis George N. , Sharif Shayan , Barta John R. , Boermans Herman J. , Smith Trevor K.
Published: September 2008

The potential for Fusarium mycotoxins to modulate immunity was studied in chickens raised to 10 weeks of age using an enteric coccidial infection model. Experimental diets included: control, diets containing grains naturally contaminated with Fusarium mycotoxins, and diets containing contaminated grains + 0.2% polymeric glucomannan mycotoxin adsorbent (GMA). Contaminated diets contained up to 3.8 μg/g deoxynivalenol (DON), 0.3 μg/g 15-acetyl DON and 0.2 μg/g zearalenone. An optimized mixture (inducing lesions without mortality) of Eimeria acervulina, E. maxima and E. tenella was used to challenge birds at 8 weeks of age. Immune parameters were studied prior to challenge, at the end of the challenge period (7 days post-inoculation, PI), and at the end of the recovery period (14 days PI). Total serum immunoglobulin (Ig) A and IgG concentrations in challenged birds fed the contaminated diet were higher than controls at the end of the challenge period. Serum concentration of IgA, but not IgG, was significantly decreased at the end of the recovery period in birds fed the contaminated diet. The percentage of CD4+ and CD8+ cell populations in blood mononuclear cells decreased significantly at the end of the challenge period in birds fed the control or the contaminated diet compared to their percentages prior to challenge. The pre-challenge percentage of CD8+ population was restored at the end of the recovery period only in birds fed the control diet. Interferon-γ (IFN-γ) gene expression in caecal tonsils was up-regulated in challenged birds fed the contaminated diet at the end of the challenge period. No significant effect of diet was observed on oocyst counts despite the changes in the studied immune parameters. It was concluded that Fusarium mycotoxins modulate the avian immune system. This modulation involves alteration of gene expression but apparently does not enhance susceptibility or resistance to a primary coccidial challenge.
Phylogeography of North African Atlas cedar (Cedrus atlantica, Pinaceae): Combined molecular and fossil data reveal a complex Quaternary history
Authors: Terrab Anass , Hampe Arndt , Lepais Olivier , Talavera Salvador , Vela Errol , Stuessy Tod F.
Published: September 2008

Northwest Africa is a major hotspot of plant biodiversity, but very little is known about the Quaternary range dynamics of plant species in this region. Here we investigate the range‐wide population structure and phylogeography of Atlas cedar (Cedrus atlantica), an emblematic forest tree endemic to Morocco and Algeria. We genotyped 261 individuals from 11 populations using AFLP markers. Data were analyzed using both conventional FST‐based techniques and Bayesian clustering. Overall population differentiation was high (FST = 0.25). Two major groups of populations were identified, one distributed through the Rif and Middle Atlas mountains in Morocco and the other through the Algerian Tell Atlas and Aurès mountains as well as the Middle Atlas. Combined molecular and fossil data indicate that C. atlantica survived the Last Glacial Maximum in at least three disjunct refugia along the coast of the Mediterranean Sea, whereas the Middle Atlas, today the core of the species range, has been colonized relatively recently (<10000 yr BP). The colonization history of individual populations has left clear imprints in their present‐day diversity, which may vary greatly even between nearby stands. Our study illustrates how integrating different data sources and analytical approaches can help elucidate complex range dynamics that would otherwise remain undeciphered.
Nutrient stress and gall flies interact to affect floral‐sex ratio in gynomonoecious Solidago altissima (Asteraceae)
Authors: Wise Michael J. , Coffey Lindsay E. , Abrahamson Warren G.
Published: September 2008

A main tenet of sex‐allocation theory is that environmental stress should lead to increased maleness because reproducing through pollen is generally cheaper than producing fruits and seeds. Though this prediction has held for many species, it has been little tested for gynomonoecious plants, in which individuals produce both female and perfect flowers. We exposed eight ramets of each of 22 genets of a gynomonoecious goldenrod, Solidago altissima (Asteraceae), to a factorial combination of nutrient stress and herbivory by the gall‐inducer Eurosta solidaginis (Tephritidae). Nutrient stress alone increased relative femaleness: Stressed ramets produced fewer flowers total and a higher ratio of ray (female) flowers to disk (perfect) flowers. Galling caused no change in fertilized ramets, but the combination of nutrient stress and galling caused an increase in relative maleness: Nutrient‐stressed, galled ramets produced fewer flowers total and had a higher disk to ray ratio. In addition to being phenotypically plastic, floral‐sex ratio had a great deal of genetic variation, with a broad‐sense heritability of 0.68. While the floral‐sex ratio responses of gynomonoecious plants may be more complicated than for plants of other breeding systems, they offer the potential to test and refine the already rich body of sex‐allocation theory.
Brassicaceae phylogeny inferred from phytochrome A and ndhF sequence data: tribes and trichomes revisited
Authors: Beilstein Mark A. , Al‐Shehbaz Ihsan A. , Mathews Sarah , Kellogg Elizabeth A.
Published: September 2008

The family Brassicaceae comprises 3710 species in 338 genera, 25 recently delimited tribes, and three major lineages based on phylogenetic results from the chloroplast gene ndhF. To assess the credibility of the lineages and newly delimited tribes, we sequenced an approximately 1.8‐kb region of the nuclear phytochrome A (PHYA) gene for taxa previously sampled for the chloroplast gene ndhF. Using parsimony, likelihood, and Bayesian methods, we reconstructed the phylogeny of the gene and used the approximately unbiased (AU) test to compare phylogenetic results from PHYA with findings from ndhF. We also combined ndhF and PHYA data and used a Bayesian mixed model approach to infer phylogeny. PHYA and combined analyses recovered the same three large lineages as those recovered in ndhF trees, increasing confidence in these lineages. The combined tree confirms the monophyly of most of the recently delimited tribes (only Alysseae, Anchonieae, and Descurainieae are not monophyletic), while 13 of the 23 sampled tribes are monophyletic in PHYA trees. In addition to phylogenetic results, we documented the trichome branching morphology of species across the phylogeny and explored the evolution of different trichome morphologies using the AU test. Our results indicate that dendritic, medifixed, and stellate trichomes likely evolved independently several times in the Brassicaceae.
Sex‐specific responses to mycorrhiza in a dioecious species
Authors: Varga Sandra , KytövIIta Minna‐Maarit
Published: September 2008

In most studies about dioecious plants, the role of arbuscular mycorrhizae (AM) and the potential sex‐specific differences between the plant hosts have been overlooked. Because plant sexes frequently differ in drought tolerance and AM fungal colonization provides higher resistance to drought, we investigated whether the relation of mycorrhizal fungi with either male or female Antennaria dioica plants differs using a factorial experiment. We hypothesized that because AM usually increase growth rate and male plants usually grow larger than females, males should gain more benefit from the mycorrhizal symbiosis in terms of mineral nutrition and water supply. Because of higher demands of carbohydrates (C) in males, we expected males to allocate less C resources to the mycorrhizal fungus so that the associated fungi should benefit less of the association with males. In contrast to our initial hypothesis, the male plants, although faster growing under drought, did not gain more symbiosis‐mediated benefits than did the females, and both sexes seemed to provide resources equally to their fungal symbiont. Therefore, we conclude that the two plant sexual morphs provide equal amounts of C to their fungal root symbionts and that they can gain specific benefits from the symbiosis, which, however, depend on soil water availability.
Anatomical basis for biophysical differences betweenPinus nigraandP. resinosa(Pinaceae) leaves
Authors: Meicenheimer Roger D. , Coffin Douglas W. , Chapman Eric M.
Published: September 2008

Differences in the flexibility ofPinus nigraandP. resinosaleaves can be used to discriminate these two similarly looking pine species from one another. When bent along the longitudinal axis,P. resinosaleaves snap, whileP. nigraleaves appear flexible. This useful field test has had no known biophysical or anatomical explanation until now. Analysis of the first order mechanics of bending and buckling of the pine needles was used to elucidate any important anatomical differences between these two species that can account for their different biophysical behaviors when bent. Neither the cross section of the total leaf area nor the inner core area between the two species differed significantly. Differences in the pattern of cell wall thickening and lignification of the endodermal layer of the inner core of the leaves best explain the differences in bending behavior. Thus, subtle variation in anatomy can influence the biophysical properties of naturally occurring structures, which in turn could have important implications for the engineering of manufactured objects.
Palaeoanellus dimorphus gen. et sp. nov. (Deuteromycotina): a Cretaceous predatory fungus
Authors: Schmidt Alexander R. , Dörfelt Heinrich , Perrichot Vincent
Published: September 2008

In habitats where nitrogen is the limiting factor, carnivorous fungi gain an advantage by preying on nematodes and other microorganisms. These fungi are abundant in modern terrestrial ecosystems, but they are not predestined for preservation as fossils. Conclusions on their evolutionary history are therefore mainly based on molecular studies that are generally limited to those taxa that have survived until today. Here we present a fossil dimorphic fungus that was found in Late Albian amber from southwestern France. This fungus possessed unicellular hyphal rings as trapping devices and formed blastospores from which a yeast stage developed. The fossil probably represents an anamorph of an ascomycete and is described as Palaeoanellus dimorphus gen. et sp. nov. Because predatory fungi with regular yeast stages are not known from modern ecosystems, the fungus is assumed to not be related to any Recent carnivorous fungus and to belong to an extinct lineage of carnivorous fungi. The inclusions represent the only record of fossil fungi that developed trapping devices, so far. The fungus lived c. 100 million years ago in a limnetic‐terrestrial microhabitat, and it was a part of a highly diverse biocenosis at the forest floor of a Cretaceous coastal amber forest.
Wood anatomy of Rauvolfioideae (Apocynaceae): a search for meaningful non‐DNA characters at the tribal level
Authors: Lens Frederic , Endress Mary E. , Baas Pieter , Jansen Steven , Smets Erik
Published: September 2008

Wood anatomical studies in the economically important Apocynaceae or dogbane family are fragmentary. This study represents a first attempt to unravel the phylogenetic significance and major evolutionary trends in the wood of the family, using existing and new microscopic wood observations within the large subfamily Rauvolfioideae. On the basis of LM and SEM observations of 91 species representing all 10 currently recognized tribes, we found that most of the tribes are characterized by a unique combination of wood characters, such as vessel grouping, vessel element length, fiber type, frequency of uniseriate rays, and fused multiseriate rays. Climbing rauvolfioid taxa can generally be distinguished from erect species by their wider vessels, tendency to form paratracheal axial parenchyma, presence of tracheids, and occurrence of laticifers in rays. With respect to the entire family, there is a general phylogenetic trend toward shorter vessel elements, a higher proportion of vessels in multiples and more vessels per multiple, higher tracheid abundance, more paratracheal parenchyma, and fewer cells per axial parenchyma strand in the more derived Apocynaceae. Most of these evolutionary trends are likely to be triggered by drier environmental conditions and/or shifts from an erect to a climbing habit.
Hybridization, polyploidy, and evolutionary transitions between monoecy and dioecy in Bryonia (Cucurbitaceae)
Authors: Volz Stefanie M. , Renner Susanne S.
Published: September 2008

Correns's 1903 (Berichte der Deutschen Botanischen Gesellschaft 21: 133–147) crosses between a monoecious and a dioecious species of Bryonia revealed the simple Mendelian inheritance of dioecy and provided the first instance of an XY sex determination system in any organism. Bryonia ranges from the Canary Islands to Central Asia and comprises seven dioecious and three monoecious species; its closest relative, Ecballium elaterium, has dioecious and monoecious populations. We used chloroplast (cp) and nuclear (nr) gene phylogenies to infer sexual system evolution in Bryonia. We also tested for associations between sexual system and ploidy level, based on published and original chromosome counts. Conflicts between cp and nr topologies imply that the dioecious hexaploid B. cretica arose from hybridization(s), probably involving the dioecious diploids B. dioica, B. syriaca, and/or B. multiflora. A tetraploid dioecious endemic on Corsica and Sardinia probably originated from B. dioica via autopolyploidy. While the cp phylogeny resolves few species relationships, the nr tree implies at least two evolutionary changes in sexual system. There is no correlation between sexual system and ploidy level. Molecular clocks suggest that the deepest divergence, between a species on the Canary Islands and the ancestor of all remaining species, occurred ca. 10 million years ago.