bluuebunny/crossref_metadata_2025 huggingface dataset:
An roc approach for evaluating functional brain mr imaging and postprocessing protocols
Authors: Constable R. Todd , Skudlarski Pawel , Gore John C.
Published: March 2007

A method that can be used to evaluate the performance of MRI methods for detecting discrete regional activations using functional MRI is presented. Computer derived receiver‐operator‐characteristic (ROC) curves have been used to evaluate quantitatively a range of conditions encountered in functional MRI studies. ROC analysis allows multiple acquisition strategies and multiple postprocessing strategies to be quantitatively and objectively compared. The authors first present this analysis technique and then illustrate its use for assessing the relative performances of different functional MRI data acquisition strategies using different gradient echo, echo‐planar imaging protocols. In addition, the authors have used the ROC analysis to evaluate and compare several methods for analyzing functional MRI data to extract regions of activation. This approach to assessing the performance of different methods is of general use and can be applied to evaluate other data acquisition protocols and postprocessing methods.
Limitations of stimulated echo acquisition mode (steam) techniques in cardiac applications
Authors: Fischer Stefan E. , Stuber Matthias , Scheidegger Markus B. , Boesiger Peter
Published: March 2007

Stimulated echoes are widely used for imaging functional tissue parameters such as diffusion coefficient, perfusion, and flow rates. They are potentially interesting for the assessment of various cardiac functions. However, severe limitations of the stimulated echo acquisition mode occur, which are related to the special dynamic properties of the beating heart and flowing blood. To the well‐known signal decay due to longitudinal relaxation and through‐plane motion between the preparation and the read‐out period of the stimulated echoes, additional signal loss is often observed. As the prepared magnetization is fixed with respect to the tissue, this signal loss is caused by the tissue deformation during the cardiac cycle, which leads to a modification of the modulation frequency of the magnetization. These effects are theoretically derived and corroborated by phantom and in vivo experiments.
Mr geometric distortion correction for improved frame‐based stereotaxic target localization accuracy
Authors: Sumanaweera Thilaka , Glover Gary H. , Hemler Paul F. , Van Elsen Petra A. Den , Martin David , Adler John R. , Napel Sandy
Published: March 2007

We present a method to correct the geometric distortion caused by field inhomogeneity in MR images of patients wearing MR‐compatible Stereotaxic frames. Our previously published distortion correction method derives patient‐dependent error maps by computing the phase‐difference of 3D images acquired at different TEs. The time difference (ΔTE = 4.9 ms at 1.5 T) is chosen such that the water and fat signals are in phase. However, ΔTE is long enough to permit phase wraps in the difference images for frequency offsets greater than 205 Hz. Phase unwrapping techniques resolve these only for connected structures; therefore, the phase difference for fiducial rods may be off by multiples of 2 π relative to the head. We remove this uncertainty by using an additional single 2D phase‐different image with ΔTE = 1 ms (during which time no phase‐wraps are typically expected) to determine the correct multiple of 2m for each rod. We tested our method in a cadaver and in a patient using CT as the gold standard. Targets in the frame coordinates were chosen from CT and compared with their locations in MR. Localizing errors using MR compared with CT were as large as 3.7 mm before correction and were reduced to less than 1.11 mm after correction.
MR gradient coil heat dissipation
Authors: Chu Kenneth C. , Rutt Brian K.
Published: March 2007

The temperature responses of five different gradient coil designs were modeled using simplified engineering equations and measured. The model predicts that the coil temperature approaches a maximum as an inverse exponential, where the maximum temperature is governed by two parameters: a local power density and a cooling term. The power density term is a function of position and is highest where the current paths have minimum widths and are closely packed. The cooling parameter consists of convective, conductive, and radiative components which can be controlled by (1) providing forced cooling, (2) having a coil former with high thermal conductivity and thin walls, and (3) varying the emissivity of the coil surfaces. For a given gradient strength, the average temperature rise is minimized by designing a coil with a small radius and thick copper. The model predicted the local temperature rise, which is also dependent on the current density, to within 5°C of measured values.
Correlation of early reduction in the apparent diffusion coefficient of water with blood flow reduction during middle cerebral artery occlusion in rats
Authors: Mancuso Anthony , Karibe Hiroshi , Rooney William D. , Zarow Gregory J. , Graham Steven H. , Weiner Michael W. , Weinstein Philip R.
Published: March 2007

To determine the relationship between reductions in the apparent diffusion coefficient of water (ADC) and in cerebral blood flow (CBF) during focal ischemia, we used diffusion‐weighted magnetic resonance (D‐MR) imaging and autoradiographic CBF analysis to examine rats subjected to 30 or 90 min of permanent middle cerebral artery (MCA) occlusion. In the 30‐min occlusion group (n = 10), the area with substantially reduced ADC (15% or more below the contralateral level [ADC15]) corresponded best to the area with CBF below 25 ml/100 g/min and was significantly smaller than the area with CBF below 50 ml/100 g/min (CBF50), a level associated with reduced protein synthesis and delayed necrosis (40 ± 13% versus 74 ± 8% of the ischemic hemisphere; P < 0.0001). In the 90‐min occlusion group (n = 6), the ADC15 area corresponded best to the CBF30 to CBF35 area and was again significantly smaller than the CBF50 area (54 ± 13% versus 73 ± 20%, P < 0.05). Thus, the area of substantially reduced ADC at 30 and 90 min represents only 53% and 74%, respectively, of the tissue at risk for infarction. These findings indicate a potential limitation in using early D‐MR imaging to predict stroke outcome.
Phased array detectors and an automated intensity‐correction algorithm for high‐resolution MR imaging of the human brain
Authors: Wald Lawrence L. , Carvajal Lucas , Moyher Susan E. , Nelson Sarah J. , Grant P. Ellen , Barkovich A. James , Vigneron Daniel B.
Published: March 2007

Two‐ and four‐coil phased array detectors were developed to increase the sensitivity and resolution of MR imaging of the human brain cortex, especially for detecting cortical dysplasias in pediatric epilepsy patients. An automated intensity correction algorithm based on an edge‐completed, low‐pass filtered image was used to correct the image intensity for the inhomogenous reception profile of the coils. Seven phased array coils were constructed and tested. The sensitivity of these coils was up to 600% higher at the surface of the cortex than that achieved with a conventional head coil and up to 30% greater at the center of the head. The sensitivity obtained was comparable with that of a conventional small surface coil, but extended over the larger dimensions of the array and previously inaccessible areas such as the top of the head. The advantages of the improved sensitivity are demonstrated with high resolution images of the brain.
Mr contrast due to intravascular magnetic susceptibility perturbations
Authors: Boxerman Jerrold L. , Hamberg Leena M. , Rosen Bruce R. , Weisskoff Robert M.
Published: March 2007

A particularly powerful paradigm for functional MR imaging of microvascular hemodynamics incorporates paramagnetic materials that create significant image contrast. These include exogenous (lanthanide chelates) and endogenous (de‐oxygenated hemoglobin) agents for mapping cerebral blood volume and neuronal activity, respectively. Accurate interpretation of these maps requires an understanding of the bio‐physics of susceptibility‐based image contrast. The authors developed a novel Monte Carlo model with which the authors quantified the relationship between microscopic tissue parameters, NMR imaging parameters, and susceptibility contrast in vivo. The authors found vascular permeability to water and the flow of erythrocytes to be relatively unimportant contributors to susceptibility‐induced ΔR2. However, pulse sequence, echo time, and concentration of contrast agent have profound effects on the vessel size dependence of ΔR2. For a model vasculature containing both capillaries and venules, the authors predicted a linear volume fraction dependence for physiological volume changes based on recruitment and dilation, and a concentration dependence that is nonlinear and pulse sequence dependent. Using the model, the authors demonstrated that spin echo functional images have greater microvascular sensitivity than gradient echo images, and that the specifics of the volume fraction and concentration dependence of transverse relaxivity change should allow for robust mapping of relative blood volume. The authors also demonstrated excellent agreement between the predictions of their model and experimental data obtained from the serial injection of superparamagnetic contrast agent in a rat model.
MR Spectroscopic imaging of collagen: Tendons and knee menisci
Authors: Gold Garry E. , Pauly John M. , Macovski Albert , Herfkens Robert J.
Published: March 2007

Water molecules associated with collagen have short transverse (T2) relaxation times. Projection‐reconstruction techniques are able to achieve an echo time (TE) much shorter than conventional techniques, allowing imaging of tissues with T2 < 5 ms. Using these techniques, a conventional 1.5‐T MRI human imaging system can directly image collagen‐associated water from knee menisci and tendons in normal volunteers and patients. Long‐T2 suppression improves the contrast between these structures and the surrounding tissue with long‐T2 relaxation times. Spectroscopic imaging provides improved lipid/water registration and information about chemical composition and relaxation times. Direct imaging of tendons and menisci may provide more information about these structures and provide a new way to assess both injury and repair.
Evaluation of muscle diseases using artificial neural network analysis of 31P MR spectroscopy data
Authors: Kari Suresh , Olsen Nancy J. , Park Jane H.
Published: March 2007

Dermatomyositis is an autoimmune disease characterized by an erythematous rash and severe muscle weakness. 31P Magnetic resonance spectroscopy (MRS) provides quantitative data for longitudinal monitoring of disease status and responses to immunosuppressive therapy. A disease variant, amyopathic dermatomyositis, presents with a typical rash but no clinical muscle weakness. However, metabolic abnormalities in the oxidative capacity of muscles of amyopathic patients during exercise were detected with 31P MRS. Because MRS provided the best quantitative data for evaluating dermatomyositis, the 31P metabolic parameters derived from the MR spectra were further processed using an artificial neural network (XERION). The neural network analyses provided additional clinical information from the weighted correlations of multiple 31P parameters, namely, inorganic phosphate, phos‐phocreatine, ATP, phosphodiesters, and selected ratios. This investigation analyzes the relative importance of the various metabolic parameters for accurate patient characterization and provides insights into the pathogenesis of the disease.
Application of a superparamagnetic iron oxide (Resovis®) for MR imaging of human cerebral blood volume
Authors: Reimer Peter , Schuierer Gerhard , Balzer Thomas , Peters Peter E.
Published: March 2007

The authors describe the feasibility of dynamic MRI using a novel superparamagnetic iron oxide contrast agent. Resovist® was injected as a bolus at doses of 4, 8, and 16 μmol Fe/kg bodyweight in three consented patients participating in a Phase 2 clinical multicenter trial for hepatic MRI. Dynamic images of the brain were obtained with a conventional FLASH sequence. Results were analyzed by evaluation of dynamic images, cerebral blood volume maps, and normalized signal intensity time curves. Resovist® enabled rapid injections and a dose‐dependent strong reduction in gray and white matter signal intensity. The small injection volume and good tolerability may enable Resovist® to serve as a perfusion agent. Dedicated clinical trials are warranted to assess the potentials of Resovist® for perfusion MRI and fMRI.
Imaging myocardial fiber architecture in vivo with magnetic resonance
Authors: Reese Timothy G. , Weisskoff Robert M. , Smith R. Neil , Rosen Bruce R. , Dinsmore Robert E. , Wedeen Van J.
Published: March 2007

Methods are presented to image the fiber architecture of the human myocardium in vitro and in vivo. NMR images are obtained of the diffusion anisotropy tensor, indicative of local myofiber orientation. Studies of cardiac necropsy specimens demonstrate classic features of ventricular myoarchitecture including the continuous endocardial to epicardial variation of fiber helix angles (angles to the ventricular circumferential direction) of approximatel ±1.3 to −1.3 radians. Cross‐fiber anisotropy is also observed. In the beating heart, NMR diffusion data must be corrected for the effects of myocardial deformation during the cardiac cycle. This correction can be performed using an independent MRI method to map the strain‐rate tensor field of the myocardium through time. Combining fiber orientation with local myocardial strain rate, local rates of myocardial fiber shortening may be computed.
Size‐restricted cluster formation and cluster maintenance technique for mobile ad hoc networks
Authors: Venkataraman Gayathri , Emmanuel Sabu , Thambipillai Srikanthan
Published: March 2007

Mobile ad hoc networks may be composed of a large number of nodes and hence a hierarchical cluster‐based structure can be employed to address the scalability issues of the large network. In this paper we propose a size‐restricted, distributed clustering strategy (cluster formation and cluster maintenance) for mobile ad hoc networks. A distributed approach where every node is responsible for the clustering decisions would avoid single‐point bottleneck failures. We use a size restrictionS, for the cluster formation and cluster maintenance. In addition, while forming the cluster we also use a diameter restrictionK. The simulations show that our strategy gives rise to a lesser number of clusters when compared to other clustering algorithms proposed by Gerlaet al., Fernadesset al.and Linet al.This is attributed to the size restriction and cluster merging that we have incorporated. The size restriction helps in better management of resources inside the cluster. Our clustering technique uses a weight‐based cluster head election strategy which results in less change in cluster head and higher cluster head lifetime when compared to the Least Cluster Head Changes (LCC) with lowest ID algorithm. The low change in cluster head and higher cluster head lifetime make our proposed algorithm suitable for high‐mobility situations. The proposed clustering strategy could be used for building the clusters required in a hierarchical structure of the ad hoc network. Copyright © 2007 John Wiley & Sons, Ltd.
Efficient characterization of the random eigenvalue problem in a polynomial chaos decomposition
Authors: Ghanem Roger , Ghosh Debraj
Published: March 2007

A new procedure for characterizing the solution of the eigenvalue problem in the presence of uncertainty is presented. The eigenvalues and eigenvectors are described through their projections on the polynomial chaos basis. An efficient method for estimating the coefficients with respect to this basis is proposed. The method uses a Galerkin‐based approach by orthogonalizing the residual in the eigenvalue–eigenvector equation to the subspace spanned by the basis functions used for approximation. In this way, the stochastic problem is framed as a system of deterministic non‐linear algebraic equations. This system of equations is solved using a Newton–Raphson algorithm. Although the proposed approach is not based on statistical sampling, the efficiency of the proposed method can be significantly enhanced by initializing the non‐linear iterative process with a small statistical sample synthesized through a Monte Carlo sampling scheme. The proposed method offers a number of advantages over existing methods based on statistical sampling. First, it provides an approximation to the complete probabilistic description of the eigensolution. Second, it reduces the computational overhead associated with solving the statistical eigenvalue problem. Finally, it circumvents the dependence of the statistical solution on the quality of the underlying random number generator. Copyright © 2007 John Wiley & Sons, Ltd.
What does the hospital diabetic clinic do for you?
Authors: Hartnell V
Published: March 2007

The work of a district's diabetic clinic was audited to assess workload; it focused on patients' reasons for attendance, outcome of their appointment and recording of specified parameters in the notes.

Results highlighted the failings of a clinic organised on traditional lines. Most appointments (70%) were for routine follow‐up, all patients were given another appointment and, for at least 27%, this was the only action undertaken. The clinic performed poorly in routine screening and was ineffective, particularly in relationship to skills and services available in primary care.
The epidemic of Indian childhood diabetes in Leicester. Social and cultural differences between cases and control population
Authors: Bodington M J , Burden A C
Published: March 2007

We have provided evidence in favour of an epidemic of childhood onset (<15 years) insulin dependent diabetes in Indian children resident in Leicester, UK. These children either come from, or their forefathers came from, the Indian Subcontinent. The present work examines the hypothesis that the amount of cultural adaption to English life is greater than their non‐diabetic peer. A trained Diabetes Specialist Health Visitor visited each family with a structured questionnaire; to enquire when the diabetes started, where they had lived previously, schooling, friends, diet and living conditions. In total. 32 patients were contacted of the 35. These families have been compared to the Leicester City Indian Census population. They are more likely to have been born in the United Kingdom; to eat meat; to live in detached or semi‐detached housing; to live in an area with few other Indians.

The preliminary results suggest that diabetic Indian children are more culturally anglicised than the non‐diabetic; a case control study is urgently required to verify this.
A comparison of the glycaemic and insulinaemic effects of an Asian and a European meal
Authors: Burden ML , Samanta A , Spalding D , Burden AC
Published: March 2007

The glycaemic and insulinaemic effects of an Asian and a European meal were compared. The Asian meal contained 1,439 kcal (14% protein, 45% carbohydrate, 41% fat, 28g dietary fibre), and the European meal 1,370 kcal (18% protein, 25% carbohydrate, 57% fat, 11g dietary fibre). Fifteen normal voiunteers were tested with each meal after an overnight fast, and on consecutive days in random order. There were no differences at fasting or after one hour between either meal. Two hours after the Asian meal, subjects had a higher degree of glycaemia, mean (SE) 5.29 (0.35) vs 4.32 (0.09) mmoI/I (p<0.02) and a higher degree of insulinaemia, mean (SE) 28.17 (6.86)vs 8.06 (1.54) mU/I (p<0.02). These effects were maintained at three hours: plasma glucose 5.12 (0.25) vs 9.84 (2.46) mU/I (p<0.01). The fasting glucose and insulin levels following the Asian meal had not been achieved at three hours so the study was repeated using 11 normal volunteers with a longer follow‐up time of six hours. Only then did the glucose values return to fasting levels, although insulin levels remained slightly elevated. These preliminary results suggest the need for more detailed long‐term observations on the metabolic effects of culturally different meals.
The accident in Bhopal: Observations 20 years later
Authors: Willey Ronald J. , Hendershot Dennis C. , Berger Scott
Published: March 2007

The most influential process safety accident passed its 20th anniversary on December 3, 2004. At an international symposium to mark the event in Kanpur, India, during the week of this anniversary, process safety practitioners from around the world assembled to discuss progress in resolving the Bhopal tragedy and in advancing the practice of process safety worldwide. This paper provides insight into the Bhopal site as attendees found it in December 2004. Since 1984, many positive steps worldwide have been made in regard to improvements in process safety and protection of personnel within chemical plants and of people in the surrounding communities. However, little visible progress has been made in decommissioning and decontaminating the Bhopal plant site, now under control of the Indian state of Madhya Pradesh. Many plant chemicals, abandoned there in 1985, were still at the site in 2004, mostly in substandard storage conditions. Mitigation recently commenced, but unconfirmed reports of the mitigation methods are concerning. The lesson learned: we all have a responsibility to ensure that events which follow a chemical accident reach a proper conclusion; and that no further undue suffering results to the general public and our fellow employees. © 2007 American Institute of Chemical Engineers Process Saf Prog 26:180–184, 2007
The potential for control of bracken in the UK using introduced herbivorous insects
Authors: Fowler Simon V.
Published: March 2007

Bracken (Pteridium aquilinum (L.) Kuhn) is an invasive native weed in the UK causing problems in upland agriculture and in land of amenity and conservation value; it may represent a risk to human health. Existing control methods such as cutting or herbicide use are subject to practical, economic or environmental constraints in many areas of the UK. Classical biological control of bracken would involve the introduction of specialist bracken‐feeding herbivores from other parts of the world. Classical biological weed control has a reasonable record of success in other parts of the world and an exemplary safety record, but remains untried in the UK. The typical development of a classical weed biocontrol programme is presented using the UK bracken programme as an example. Finally the current position of this classical biocontrol programme is reviewed with an assessment of the prospects for the future. With appropriate funding, a full field release of at least one species of South African bracken‐feeding moth should be achieved during the mid‐1990s.
Biocontrol of soil‐borne plant pathogens: Concepts and their application
Authors: Deacon James W. , Berry Lorraine A.
Published: March 2007

A few soil‐borne plant pathogens have been controlled successfully by commercial formulations of biocontrol agents, but many attempts to develop biocontrol inoculants, although promising under experimental conditions, have met with difficulties in practice. The reasons for this are discussed in this review, which outlines some of the major findings on the behaviour of microbial inoculants in soil. It is emphasized that biocontrol also occurs naturally in current agricultural practice and can be exploited purposely, but it is vulnerable to disruption by agrochemicals or mismanagement. The future of biocontrol of soilborne plant pathogens probably lies in integrated (biorational) control systems that combine the use of commercial inoculants, where appropriate, with management practices that maintain and enhance the natural biocontrol systems.
Adoption of XP practices in the industry—A survey
Authors: Bowers Alexia N. , Sangwan Raghvinder S. , Neill Colin J.
Published: March 2007

Agile software development has recently become popular in the software industry. The methodologies in the Agile family are considered to be based on best practices. The most popular approach, Extreme Programming (XP), recommends certain best practices during the requirements gathering, implementation and testing phases of software development. In this paper, the authors analyze the best practices according to data from recent case studies and survey studies to see if and how they are followed. Metaphor was the least used practice, while unit testing was one of the most popular. Most of the practices varied across studies and projects. Agile software development is evolutionary in nature, so customizing the practices is still well within its sounds. Copyright © 2007 John Wiley & Sons, Ltd.
Morphological analysis of osteoclastogenesis induced by RANKL in mouse bone marrow cell cultures
Authors: Gardner Colin R.
Published: March 2007

Under the influence of RANKL, in the presence of M‐CSF, monocyte/macrophage precursor cells entered the osteoclast lineage and expressed the osteoclast marker tartrate‐resistant acid phosphatase (TRAP). These cells were motile and began to differentiate by contacting and fusing together, initially forming cells with several nuclei. All sizes of cells continued to fuse, forming larger cells with more than 6 and as many as 50 nuclei. The degree of osteoclastogenesis was related to the concentration of RANKL. High cell density changed osteoclast morphology from a more rounded form with cytoplasm extended all round the cell to a form with cytoplasm concentrated around the nuclei and more restricted multiple cytoplasmic extensions. At optimal cell density and RANKL concentrations the large numbers of rounded cells fused into large cytoplasmic masses. On reaching a critical size, osteoclasts assumed a spread morphology with a peripheral ring structure. Most of the nuclei were associated with the peripheral ring. When cytoplasmic masses were present, rings also formed within the mass, often with no contact with the cell periphery. All forms of RANKL‐induced osteoclastogenesis were blocked by the endogenous decoy receptor osteoprotegerin and were also strongly reduced by calcitonin, with the later arriving morphological categories being the first to disappear.
Dismantling an Earnings-Related Social Pension Scheme: Germany's New Pension Policy
Authors: SCHMÄHL WINFRIED
Published: March 2007

A paradigm shift in pension policy decided by the German red–green coalition government will considerably affect the level and structure of pension benefits as well as the mix of public and private old-age security arrangements. The article starts with a brief outline of the pension schemes as they had been designed before the recent decisions, and with a few remarks on the reasons for current reform debates. The major measures of the 2001 Pension Reform are then described. The focus of the article is on the effects of the reform for (personal) income distribution and institutional design. A partial shift from (mandatory) public (pay-as-you-go financed) pensions to (voluntary) private (capital-funded) pensions and from defined benefit towards defined contribution will, among other things, reduce the benefit level in the social pension insurance. A large number of contributors – even after many years of paying contributions – will only receive benefits below the social assistance level. It can be expected that this development will transform the present earnings-related statutory pension scheme – which has a strong contribution–benefit link and is aimed at income smoothing over the lifecycle – into a basic, highly redistributive pension scheme, aimed mainly at avoiding poverty. Income inequality in old age is expected to increase as a result of the new strategy in pension policy.
Seed predation and seedling herbivory as factors in tree recruitment failure on predator-free forested islands
Authors: Lopez Lawrence , Terborgh John
Published: March 2007

Sapling mortality exceeds recruitment for many species of trees in the dry forest of 16-y-old islets in Lago Guri, Venezuela. Failure of sapling recruitment is potentially attributable to the aberrant animal communities of these islands. Predators of vertebrates are absent and densities of pollinators and seed dispersers are substantially reduced in comparison to the nearby mainland. In contrast, predators of invertebrates, rodents and generalist herbivores (leaf-cutter ants, howler monkeys, common iguanas) are present at greatly elevated densities. Given these distortions in the animal community, recruitment failure of saplings could potentially be attributable to several causes: reduced pollination or seed dispersal, excessive seed predation or seedling herbivory. Two of these hypotheses are tested herein. The seed predation hypothesis predicts greater seed removal in the presence of hyperabundant rodents, and the seedling herbivory hypothesis predicts reduced seedling survival in the presence of hyperabundant herbivores. Seed removal trials were conducted with 18 species of forest trees, using both exposed and lightly buried seeds. Seed removal was not generally higher on islands supporting hyperabundant rodents, contrary to the seed predation hypothesis. Seedlings exposed to herbivores for 4 mo suffered the highest mortality on small islands supporting hyperabundant rodents and leaf-cutter ants. Saplings survived equally well in cages open to arthropods + rodents as in cages open only to arthropods, suggesting that there was no additive effect of rodents on seedling mortality. Current evidence points to excessive seedling herbivory by arthropods, especially by leaf-cutter ants, as the principal cause of recruitment failure on predator-free Lago Guri islets.
Seed rain during initial colonization of abandoned pastures in the premontane wet forest zone of southern Costa Rica
Authors: Dosch Jerald J. , Peterson Chris J. , Haines Bruce L.
Published: March 2007

Understanding tropical succession requires insight into propagule availability, which constrains possible woody plant recruitment, yet seed rain composition in multiple post-agricultural sites has seldom been examined. We monitored seed rain for 60 wk in five abandoned pastures in southern Costa Rica, collecting a total of 1 140 688 seeds of 165 morphospecies. Most seeds (80.1%) arrived during the wet season. Species richness was highest in the wet season and greater in forest than in pasture. Seed rain density was greatest at the forest/pasture edge and decreased drastically just a few metres into pastures. In and near the forest, animal-dispersed seeds were more abundant than seeds dispersed by other means, while wind-dispersed taxa increased in relative importance at greater distances from the forest. Total seed input to pastures did not reflect size of adjacent forest fragments, although seed rain density varied more than threefold among sites. Among-site variation in density of regenerating woody seedlings was roughly proportional to among-site variation in seed rain. Morphospecies composition differed significantly among sites. Also, seed rain and woody plant colonists were rather dissimilar in composition, suggesting that while propagule availability is necessary for early woody plant establishment, it is a poor predictor of successional trajectory.
Leaf litter diversity and shredder preferences in an Australian tropical rain-forest stream
Authors: Bastian Mikis , Boyero Luz , Jackes Betsy R. , Pearson Richard G.
Published: March 2007

Consumption of terrestrial leaf litter by stream invertebrates is an important process, but little attention has been paid to the influence of leaf diversity on the process. Tropical forests are known to have much greater diversity of plant species than their temperate counterparts, but studies of litter processing in tropical streams have not explicitly addressed this issue. This paper documents the streambed leaf litter composition and diversity of an Australian tropical rain-forest stream and the leaf preferences of consumers in the stream. We hypothesized that there would be high diversity of litter in the stream and that the shredders would have broad preferences, given that litterfall of any one species would occur over a restricted period. Leaf litter was characterized by high species diversity (81 species from one stream reach sampled on two occasions). Leaf consumers (‘shredders’) were associated with a relatively broad suite of leaf species (38 species) and did not indicate clear leaf preferences. However, in a laboratory feeding experiment, using the three most common shredder species and some of the most abundant leaf species in the stream, all shredder species exhibited clear preference for a single leaf species (Endiandra bessaphila). Preference for this and other species was affected by the conditioning age of leaves (i.e. the length of time leaves were exposed to leaching and microbial colonization), with conditioned leaves usually being preferred, and previously non-selected leaves becoming more palatable with conditioning. Thus, different successional stages were more important than the identity of leaf species in determining the distribution of shredders among the leaves.
The use of clinical profiles in the investigation of foodborne outbreaks in restaurants: United States, 1982–1997
Authors: HEDBERG C. W. , PALAZZI-CHURAS K. L. , RADKE V. J. , SELMAN C. A. , TAUXE R. V.
Published: March 2007

Improving the efficiency of outbreak investigation in restaurants is critical to reducing outbreak-associated illness and improving prevention strategies. Because clinical characteristics of outbreaks are usually available before results of laboratory testing, we examined their use for determining contributing factors in outbreaks caused by restaurants. All confirmed foodborne outbreaks reported to the Centers for Disease Control and Prevention (CDC) from 1982 to 1997 were reviewed. Clinical profiles were developed based on outbreak characteristics. We compared the percentage of contributing factors by known agent and clinical profile to their occurrence in outbreaks of unclassified aetiology. In total, 2246 foodborne outbreaks were included: 697 (31%) with known aetiology and 1549 (69%) with aetiology undetermined. Salmonella accounted for 65% of outbreaks with a known aetiology. Norovirus-like clinical profiles were noted in 54% of outbreaks with undetermined aetiology. Improper holding times and temperatures were associated with outbreaks caused by Clostridium perfringens, Bacillus cereus, Staphylococcus aureus, and Salmonella, and also with outbreaks of undetermined aetiology that fitted diarrhoea-toxin and vomiting-toxin clinical profiles. Poor personal hygiene was associated with norovirus, Shigella, and Salmonella, and also with outbreaks that fitted norovirus-like and vomiting-toxin clinical profiles. Contributing factors were similar for outbreaks with known aetiology and for those where aetiology was assigned by corresponding clinical profile. Rapidly categorizing outbreaks by clinical profile, before results of laboratory testing are available, can help identification of factors which contributed to the occurrence of the outbreak and will promote timely and efficient outbreak investigations.
Ein Vorname sagt mehr als 1000 Worte
Authors: Rudolph Udo , Böhm Robert , Lummer Michaela
Published: March 2007

Zusammenfassung. Die vorliegende Studie präsentiert Wortnormen für 30 männliche und 30 weibliche deutsche Vornamen (modern, altmodisch und zeitlos) hinsichtlich der Wahrnehmung von Alter, Attraktivität und Intelligenz des Namensträgers/der Namensträgerin. Es wurden 104 jüngere (unter 30 Jahre) und 42 ältere (über 50 Jahre) Personen befragt. Wir untersuchen hierbei (1) Stereotype, welche die Wahrnehmung von Vornamensträgern und -trägerinnen beeinflussen, (2) die Grundlagen für die Entstehung “zeitloser Vornamen” und (3) die Gründe für die Vornamenswahl bei eigenen Kindern. Die Ergebnisse zeigen, dass (1) die Vornamenwahrnehmung vom (zugeschriebenen) Alter der Namensträger und -trägerinnen und dem Alter der Befragten abhängt. (2) Es finden sich zwei, in der Alterswahrnehmung unterschiedliche Ordnungen zeitloser Vornamen. (3) Die Präferenzen bei der Benennung eigener Kinder unterliegen großen zeitlichen Schwankungen.
Regulatorischer Fokus
Authors: Werth Lioba , Förster Jens
Published: March 2007

Zusammenfassung. Gemäß der Theorie des regulatorischen Fokus (RFT; Higgins, 1997 ) können Personen Ziele über zwei unterschiedliche selbstregulative Systeme erreichen: indem sie entweder ihre Aufmerksamkeit auf das Erreichen von Idealen und Gewinnen richten und so genannte Promotionsstrategien einsetzen (Promotionsfokus) oder aber sich auf die Erfüllung ihrer Verantwortlichkeiten und Pflichten konzentrieren und dabei so genannte Preventionsstrategien verwenden (Preventionsfokus). Der vorliegende Beitrag gibt einen Überblick der derzeitigen Befundlage zur RFT.
Auswahl von Patienten für eine Gruppenpsychotherapie
Authors: Löffler Julia , Bormann Bianca , Burlingame Gary , Strauß Bernhard
Published: March 2007

Zusammenfassung. Mit dem Group Selection Questionnaire (GSQ) wurde ein ökonomisches Instrument für die Klinik und Forschung entwickelt, das Informationen über die Erwartungen von Patienten an eine Gruppentherapie, ihre Bereitschaft, mit anderen Teilnehmern in einer positiven Art zu interagieren und ihre Tendenz, in einer Gruppe dominierendes Verhalten zu zeigen, erheben soll. In der vorliegenden Arbeit wurde versucht, die Ergebnisse einer von Cox et al. (2004) in den USA beschriebenen Studie zum GSQ an zwei klinischen Stichproben (n = 267 und n = 385) aus dem deutschen Sprachraum zu replizieren. Zwei Teilstichproben von Psychotherapiepatient(inn)en aus acht bzw. fünf stationären Behandlungseinrichtungen wurden im Rahmen der Studie untersucht. Die Patienten wurden gebeten, einmalig vor der ersten Gruppensitzung die 19 Fragen des GSQ zu beantworten. Ziel dieser Studie war es, die Faktorenstruktur des GSQ durch konfirmatorische Faktorenanalysen zu überprüfen. Die Überprüfung erfolgte vorrangig mit Hilfe von Strukturgleichungsmodellen. An der ersten Stichprobe wurde deutlich, dass die deutschen Patienten eine moderate Übereinstimmung mit den amerikanischen Probanden bei der Beantwortung des GSQ zeigten. Mit einem geringfügig modifizierten Modell konnte allerdings eine sehr gute Übereinstimmung erzielt werden. Die verbleibenden Items luden auf denselben Faktoren wie dies in früheren GSQ-Studien mit einer bosnischen bzw. einer amerikanischen Stichprobe gezeigt werden konnte ( Cox et al. 2004 ). Die Kreuzvalidierung dieses Ergebnisses an einer weiteren Patientenstichprobe bestätigte letztlich das Faktorenmodell, wenngleich insgesamt gesehen die psychometrische Qualität der Subskala Dominanz noch zu wünschen übrig lässt. Der GSQ könnte ein geeignetes Screening-Instrument werden, mit dessen Hilfe Kliniker effizient bereits vor Behandlungsbeginn Aussagen darüber treffen können, welche Patienten mit höherer Wahrscheinlichkeit eine Gruppentherapie frühzeitig abbrechen bzw. weniger profitieren werden. Um dies zu bestätigen, sind nun allerdings auch im deutschen Sprachraum Verlaufsstudien nötig.
Ocean‐atmosphere partitioning of anthropogenic carbon dioxide on centennial timescales
Authors: Goodwin Philip , Williams Richard G. , Follows Michael J. , Dutkiewicz Stephanie
Published: March 2007

A theory for the ocean‐atmosphere partitioning of anthropogenic carbon dioxide on centennial timescales is presented. The partial pressure of atmospheric CO2 (PCO2) is related to the external CO2 input (ΔΣC) at air‐sea equilibrium by: PCO2 = 280 ppm exp(ΔΣC/[IA + IO/R]), where IA, IO, and R are the pre‐industrial values of the atmospheric CO2 inventory, the oceanic dissolved inorganic carbon inventory, and the Revelle buffer factor of seawater, respectively. This analytical expression is tested with two‐ and three‐box ocean models, as well as for a version of the Massachusetts Institute of Technology general circulation model (MIT GCM) with a constant circulation field, and found to be valid by at least 10% accuracy for emissions lower than 4500 GtC. This relationship provides the stable level that PCO2 reaches for a given emission size, until atmospheric carbon is reduced on weathering timescales. On the basis of the MIT GCM, future carbon emissions must be restricted to a total of 700 GtC to achieve PCO2 stabilization at present‐day transient levels.
Surface current effects on the fetch‐limited growth of wave energy
Authors: Haus Brian K.
Published: March 2007

To study the fetch‐limited growth of wind wave energy over a region with significant lateral shear of the current field, this study exploited data obtained from two linear phased‐array High Frequency (HF) radar systems. Both the near‐surface currents and wave energy and period were mapped over the highly sheared inshore boundary of the Florida Current. The wave energy growth during two periods when the winds were steady for >12 hours and were directed offshore was computed over a range of fetches from 5 to 45 km. The observed energy growth rates were significantly (∼50 %) lower than predicted by the Donelan et al. (1992) empirical formulation over the high vorticity region. The reduced growth rate was consistent with a shift of the wind stress direction into the current direction due to refraction of the wave field. Dimensionless wave energy increased by as much as 100% over neighboring values when the vertical component of the surface current vorticity was a global minimum. While trapping and enhancement of wave energy is predicted by wave ray theory, it has never before been confirmed within the Florida Current with coincident wave and current measurements.
Methylamine‐dependent release of nitric oxide and dopamine in the CNS modulates food intake in fasting rats
Authors: Raimondi L , Alfarano C , Pacini A , Livi S , Ghelardini C , DeSiena G , Pirisino R
Published: March 2007

Background and purpose:

Methylamine is an endogenous aliphatic amine exhibiting anorexigenic properties in mice. The aim of this work was to show whether methylamine also modifies feeding behaviour in rats and, if so, to identify the mediator(s) responsible for such effects.

Experimental approach:

Microdialysis experiments with the probe inserted in the periventricular hypothalamic nucleus were carried out in 12 h starved, freely moving rats. Collected perfusate samples following methylamine injection (i.c.v.) were analysed for nitric oxide by chemiluminescence and for dopamine and 5‐hydroxytryptamine content by HPLC. Kv1.6 potassium channel expression was reduced by antisense strategy and this decrease quantified by semi‐quantitative RT‐PCR analysis.

Key results:

Methylamine showed biphasic dose‐related effects on rat feeding. At doses of 15–30μg per rat, it was hyperphagic whereas higher doses (60–80μg) were hypophagic. Methylamine stimulated central nitric oxide (+115% vs. basal) following hyperphagic and dopamine release (60% over basal values) at hypophagic doses, respectively. Treatment withL‐NG‐nitro‐L‐arginine‐methyl ester (i.c.v. 2μg 10μl−1) or withα‐methyl‐p‐tyrosine (i.p. 100 mg kg−1) before methylamine injection, reduced nitric oxide output and hyperphagia, or dopamine release and hypophagia respectively. Moreover, hypophagia and hyperphagia, as well as nitric oxide and dopamine release were significantly reduced by down‐regulating brain Kv1.6 potassium channel expression.

Conclusions and implications:

The effects of methylamine on feeding depend on the hypothalamic release of nitric oxide and dopamine as a result of interaction at the Kv1.6 channels. The study of methylamine levels in the CNS may provide new perspectives on the physio‐pathogy of alimentary behaviour.

British Journal of Pharmacology(2007)150, 1003–1010. doi:10.1038/sj.bjp.0707170
The carbon monoxide‐releasing molecule CORM‐2 inhibits the inflammatory response induced by cytokines in Caco‐2 cells
Authors: Megías J , Busserolles J , Alcaraz M J
Published: March 2007

Background and purpose:

Recent evidence indicates that carbon monoxide‐releasing molecules (CO‐RMs) exhibit potential anti‐inflammatory properties. In the present study, we have investigated whether tricarbonyl dichloro ruthenium(II) dimer (CORM‐2) can control the inflammatory response induced by cytokines in a human colonic epithelial cell line, Caco‐2.

Experimental approach:

Caco‐2 cells were preincubated with CORM‐2 for 30 minutes and then stimulated with interleukin (IL)‐1β, tumor necrosis factor‐α and interferon‐γ for different times. Gene expression was analyzed by real‐time PCR. Protein expression was investigated by Western blot and ELISA. Transcription factor activation was determined by the luciferase method.

Key results:

We have shown that CORM‐2 significantly decreased the mRNA expression of nitric oxide synthase‐2 (NOS‐2) and the production of nitrite, in Caco‐2 cells stimulated with cytokines. IL‐8, IL‐6 and metalloproteinase‐7 (MMP‐7) mRNA and protein were also significantly reduced by CORM‐2. Time‐course and small interfering RNA studies suggest that inhibition of IL‐6 plays a role in the regulation of MMP‐7 expression by CORM‐2. These effects of CORM‐2 can be dependent on the modulation of nuclear factor‐κB (NF‐κB), activator protein‐1, CCAT/enhancer binding protein and the phosphorylated forms of NF‐κB inhibitory protein‐α, c‐Jun N‐terminal protein kinase 1/2, p38 and extracellular signal‐regulated kinase 1/2.

Conclusions and Implications:

CORM‐2 can regulate a number of genes relevant in intestinal inflammation and cancer progression. These findings provide new insights into the anti‐inflammatory properties and potential applications of this class of compounds.

British Journal of Pharmacology (2007) 150, 977–986. doi:10.1038/sj.bjp.0707184
Stimulatory action of protein kinase Cɛ isoform on the slow component of delayed rectifier K+ current in guinea‐pig atrial myocytes
Authors: Toda H , Ding W‐G , Yasuda Y , Toyoda F , Ito M , Matsuura H , Horie M
Published: March 2007

Background and purpose:

Protein kinase C (PKC) comprises at least twelve isoforms and has an isoform‐specific action on cardiac electrical activity. The slow component of delayed rectifier K+ current (I
Ks) is one of the major repolarizing currents in the hearts of many species and is also potentiated by PKC activation. Little is known, however, about PKC isoform(s) functionally involved in the potentiation of I
Ks in native cardiac myocytes.

Experimental approach:

IKs was recorded from guinea‐pig atrial myocytes, using the whole‐cell configuration of patch‐clamp method.

Key results:

Bath application of phenylephrine enhanced IKs concentration‐dependently with EC50 of 5.4 μM and the maximal response (97.1±11.9% increase, n=16) was obtained at 30 μM. Prazosin (1 μM) almost totally abolished the potentiation of IKs by phenylephrine, supporting the involvement of α1‐adrenoceptors. The stimulatory action of phenylephrine was significantly, if not entirely, inhibited by the general PKC inhibitor bisindolylmaleimide I but was little affected by Gö‐6976, Gö‐6983 and rottlerin. Furthermore, this stimulatory effect was significantly reduced by dialyzing atrial myocytes with PKCɛ‐selective inhibitory peptide ɛV1‐2 but was not significantly affected by conventional PKC isoform‐selective inhibitory peptide βC2‐4. Phorbol 12‐myristate 13‐acetate (PMA) at 100 nM substantially increased IKs by 64.2±1.3% (n=6), which was also significantly attenuated by an internal dialysis with ɛV1‐2 but not with βC2‐4.

Conclusions and implications:

The present study provides experimental evidence to suggest that, in native guinea‐pig cardiac myocytes, activation of PKC contributes to α1‐adrenoceptor‐mediated potentiation of I
Ks and that ɛ is the isoform predominantly involved in this PKC action.

British Journal of Pharmacology (2007) 150, 1011–1021. doi:10.1038/sj.bjp.0707191
Reversal modes in magnetic nanotubes
Authors: Landeros P. , Allende S. , Escrig J. , Salcedo E. , Altbir D. , Vogel E. E.
Published: March 2007

The magnetic switching of ferromagnetic nanotubes is investigated as a function of their geometry. Two independent methods are used: Numerical simulations and analytical calculations. It is found that for long tubes the reversal of magnetization is achieved by two mechanisms: The propagation of a transverse domain wall or propagation of a vortex domain wall depending on the internal and external radii of the tube.