bluuebunny/crossref_metadata_2025 huggingface dataset:
The 2.5-dimensional equivalent sources method for directly exposed and shielded urban canyons
Authors: Hornikx Maarten , Forssén Jens
Published: January 2008

When a domain in outdoor acoustics is invariant in one direction, an inverse Fourier transform can be used to transform solutions of the two-dimensional Helmholtz equation to a solution of the three-dimensional Helmholtz equation for arbitrary source and observer positions, thereby reducing the computational costs. This previously published approach [D. Duhamel, J. Sound Vib. 197, 547–571 (1996)] is called a 2.5-dimensional method and has here been extended to the urban geometry of parallel canyons, thereby using the equivalent sources method to generate the two-dimensional solutions. No atmospheric effects are considered. To keep the error arising from the transform small, two-dimensional solutions with a very fine frequency resolution are necessary due to the multiple reflections in the canyons. Using the transform, the solution for an incoherent line source can be obtained much more efficiently than by using the three-dimensional solution. It is shown that the use of a coherent line source for shielded urban canyon observer positions leads mostly to an overprediction of levels and can yield erroneous results for noise abatement schemes. Moreover, the importance of multiple façade reflections in shielded urban areas is emphasized by vehicle pass-by calculations, where cases with absorptive and diffusive surfaces have been modeled.
High-resolution plane-wave decomposition in an auditorium using a dual-radius scanning spherical microphone array
Authors: Rafaely Boaz , Balmages Ilya , Eger Limor
Published: January 2008

The spatial and temporal distribution of early reflections in an auditorium is considered important for sound perception. Previous studies presented measurement and analysis methods based on spherical microphone arrays and plane-wave decomposition that could provide information on the direction and time of arrival of early reflections. This paper presents recent results of room acoustics analysis based on a spherical microphone array, which employs high spherical harmonics order for improved spatial resolution, and a dual-radius spherical measurement array to avoid ill-conditioning at the null frequencies of the spherical Bessel function. Spatial-temporal analysis is performed to produce directional impulse responses, while analysis based on the windowed Fourier transform is employed to detect direction of arrival of individual reflections at selected frequencies. Experimental results of sound-field analysis in a real auditorium are also presented.
Urgency is a non-monotonic function of pulse rate
Authors: Russo Frank A. , Jones Jeffery A.
Published: January 2008

Magnitude estimation was used to assess the experience of urgency in pulse-train stimuli (pulsed white noise) ranging from 3.13 to 200Hz. At low pulse rates, pulses were easily resolved. At high pulse rates, pulses fused together leading to a tonal sensation with a clear pitch level. Urgency ratings followed a nonmonotonic (polynomial) function with local maxima at 17.68 and 200Hz. The same stimuli were also used in response time and pitch scaling experiments. Response times were negatively correlated with urgency ratings. Pitch scaling results indicated that urgency of pulse trains is mediated by the perceptual constructs of speed and pitch.
Joint seismic-infrasonic processing of recordings from a repeating source of atmospheric explosions
Authors: Gibbons Steven J. , Ringdal Frode , Kværna Tormod
Published: January 2008

A database has been established of seismic and infrasonic recordings from more than 100 well-constrained surface explosions, conducted by the Finnish military to destroy old ammunition. The recorded seismic signals are essentially identical and indicate that the variation in source location and magnitude is negligible. In contrast, the infrasonic arrivals on both seismic and infrasound sensors exhibit significant variation both with regard to the number of detected phases, phase travel times, and phase amplitudes, which would be attributable to atmospheric factors. This data set provides an excellent database for studies in sound propagation, infrasound array detection, and direction estimation.
Estimation of interaural level difference based on anthropometry and its effect on sound localization
Authors: Watanabe Kanji , Ozawa Kenji , Iwaya Yukio , Suzuki Yôiti , Aso Kenji
Published: January 2008

Individualization of head-related transfer functions (HRTFs) is important for highly accurate sound localization systems such as virtual auditory displays. A method to estimate interaural level differences (ILDs) from a listener’s anthropometry is presented in this paper to avoid the burden of direct measurement of HRTFs. The main result presented in this paper is that localization is improved with nonindividualized HRTF if ILD is fitted to the listener. First, the relationship between ILDs and the anthropometric parameters was analyzed using multiple regression analysis. The azimuthal variation of the ILDs in each 1/3-octave band was then estimated from the listener’s anthropometric parameters. A psychoacoustical experiment was carried out to evaluate its effectiveness. The experimental results show that the adjustment of the frequency characteristics of ILDs for a listener with the proposed method is effective for localization accuracy.
Validation of the auditory hazard assessment algorithm for the human with impulse noise data
Authors: Price G. Richard
Published: January 2008

Predicting auditory hazard from intense acoustic impulses, such as weapons fire or airbags, has been an intractable problem. The U.S. Army developed a theoretically based mathematical model of the ear designed to predict such hazards [the Auditory Hazard Assessment Algorithm for the Human (AHAAH)]. To validate it as a predictor of hazard, data from the literature (wave forms and changes in hearing sensitivity) were processed with the model in order to predict the onset of unacceptable threshold shift (25dB or more) in the 95th percentile human ear. For comparison, alternate standards MIL-STD-1747D and A-weighted energy were also used to compute hazards for the same data. The primary dataset was that of the US Army’s “Albuquerque studies” (53 different cases) and other impulses from the literature (19 additional predictions). The AHAAH model predicted correctly in over 95% of the cases, the MIL-STD-1474D was correct in 42% of the cases, and A-weighted energy was correct in 25% of the cases. Errors for all methods tended to be in the direction of overprediction of hazard. In addition to greatly increased accuracy, the AHAAH model also has the advantage of being theoretically based and including novel diagnostic features.
Retrieving reflection responses by crosscorrelating transmission responses from deterministic transient sources: Application to ultrasonic data
Authors: Draganov Deyan , Wapenaar Kees , Thorbecke Jan , Nishizawa Osamu
Published: January 2008

By crosscorrelating transmission recordings of acoustic or elastic wave fields at two points, one can retrieve the reflection response between these two points. This technique has previously been applied to measured elastic data using diffuse wave-field recordings. These recordings should be relatively very long. The retrieval can also be achieved by using deterministic transient sources with the advantage of using short recordings, but with the necessity of using many P-wave and S-wave sources. Here, it is shown how reflections were retrieved from the cross correlation of transient ultrasonic transmission data measured on a heterogeneous granite sample.
Chirp zeta transform beamforming for three-dimensional acoustic imaging
Authors: Palmese Maria , Trucco Andrea
Published: January 2008

This letter considers the possibility of the generation of three-dimensional acoustic images with a limited computational load by considering the extension of Chirp zeta transform beam forming to the case of planar array and near-field conditions. This extension, with a few innovative solutions, allows for a dramatic reduction in the number of on-line operations over traditional time-domain beamforming.
Prey availability and diet of the Eurasian otter (Lutra lutra) on a large reservoir and associated tributaries
Authors: Sales-Luís T. , Pedroso N.M. , Santos-Reis M.
Published: January 2008

Eurasian otter, Lutra lutra (L., 1758), spraints collected at the Aguieira hydroelectric dam (central Portugal, n = 916) and tributaries (n = 412) were analysed to assess diet compared with prey availability. Fish and crayfish abundances in the reservoir were assessed with fyke and trammel nets. Prey availability in the tributaries was estimated by electrofishing. In both the reservoir and its tributaries, fish were the main prey and consisted predominantly of Lepomis gibbosus (L., 1758) (60%–65% of occurrences), which is an introduced species of Centrachidae that is abundant in the reservoir but is almost absent in the tributaries. These data suggest that otters using the tributaries feed predominantly in the reservoir. Seasonal dietary variations corresponded to increased availability of nonfish prey categories. Capture vs. consumption analyses demonstrated that otters did not consume L. gibbosus according to its availability. In fact, L. gibbosus was consumed less frequently when other prey species were more available (e.g., amphibians, eels, barbells). The tributaries offer important otter refuge areas that are scarce at the edge of the reservoir, and so, in large reservoirs care should be taken to minimize disturbance in the surrounding catchments. Results indicate that otter populations make use of these conjoint systems to ensure their survival.
At what distance do wolves move away from an approaching human?
Authors: Karlsson J. , Eriksson M. , Liberg O.
Published: January 2008

Management of controversial animals, like large carnivores, in multi-use landscapes is highly dependent on human tolerance. Human fear of wolves ( Canis lupus L., 1758) is known to be an important variable affecting human attitudes towards wolves. Successful management of wolves thus forces managers to respond to human fear of wolves. In this study, we assess the distance at which radio-collared wolves move away from an approaching human, also called the flight initiation distance (FID), and how FID is affected by wind speed and wind direction. We used silent VHF receivers and walked at normal pace towards radio-collared wolves. When approaching the wolves, we made no attempt to hide or walk in a less noisy manner. In the 34 experimental provocations, wolves moved away when the approaching human was between 17 and 310 m away. The mean FID was 106 m. FID was negatively correlated with wind speed. One hour after having been roused by the approaching human, wolves had moved a median distance of 1.2 km.
The impacts of anthropogenic ocean noise on cetaceans and implications for management
Authors: Weilgart L.S.
Published: January 2008

Ocean noise pollution is of special concern for cetaceans, as they are highly dependent on sound as their principal sense. Sound travels very efficiently underwater, so the potential area impacted can be thousands of square kilometres or more. The principal anthropogenic noise sources are underwater explosions (nuclear and otherwise), shipping, seismic exploration by mainly the oil and gas industries, and naval sonar operations. Strandings and mortalities of especially beaked whales (family Ziphiidae) have in many cases been conclusively linked to noise events such as naval maneuvers involving tactical sonars or seismic surveys, though other cetacean species may also be involved. The mechanisms behind this mortality are still unknown, but are most likely related to gas and fat emboli at least partially mediated by a behavioral response, such as a change in diving pattern. Estimated received sound levels in these events are typically not high enough to cause hearing damage, implying that the auditory system may not always be the best indicator for noise impacts. Beaked whales are found in small, possibly genetically isolated, local populations that are resident year-round. Thus, even transient and localized acoustic impacts can have prolonged and serious population consequences, as may have occurred following at least one stranding. Populations may also be threatened by noise through reactions such as increased stress levels, abandonment of important habitat, and “masking” or the obscuring of natural sounds. Documented changes in vocal behavior may lead to reductions in foraging efficiency or mating opportunities. Responses are highly variable between species, age classes, behavioral states, etc., making extrapolations problematic. Also, short-term responses may not be good proxies of long-term population-level impacts. There are many examples of apparent tolerance of noise by cetaceans, however. Noise can also affect cetaceans indirectly through their prey. Fish show permanent and temporary hearing loss, reduced catch rates, stress, and behavioral reactions to noise. Management implications of noise impacts include difficulties in establishing “safe” exposure levels, shortcomings of some mitigation tools, the need for precaution in the form of reducing noise levels and distancing noise from biologically important areas, and the role of marine protected areas and monitoring in safeguarding cetaceans especially from cumulative and synergistic effects.
DRIVEN MESOSCOPIC ELECTRIC CIRCUITS
Authors: KHEIRANDISH F. , PAHLAVANI H.
Published: January 2008

The quantum theory for a mesoscopic electric circuit with charge discreteness is investigated. The persistent current on a quantum ring using an algebraic approach have been obtained. The energy spectrum and the persistent current of a quantum LC-design mesoscopic circuit, with a time-dependent external source, have been found.
PHONON PROPERTIES OF FIBONACCI CHAINS
Authors: LI LIQIN , YANG XIANGBO
Published: January 2008

This paper presents the phonon properties of Fibonacci chains in the harmonic approximation theoretically. Using the transfer matrix method, we investigate the influence of the atom masses on the phonon spectra of quasiperiodic chains. Our calculations show that the atom masses determine the widths and positions of gaps. Moreover, the phonon spectra of Fibonacci chains made by two atoms are self-similar in the high-frequency regions.
ENHANCED TELEPORTATION THROUGH ANISOTROPIC HEISENBERG QUANTUM SPIN CHAINS
Authors: HAO XIANG , ZHU SHIQUN
Published: January 2008

The teleportation via the channel of the thermal equilibrium states in anisotropic Heisenberg XYZ chains is analyzed. It is found that there are the critical temperatures below which entanglement teleportation can be realized. Entanglement teleportation is enhanced through anisotropic XYZ chains in contrast to the isotropic Heisenberg one. Anisotropic spin exchanges can increase these critical temperatures for the teleportation. Entanglement can be transferred in the ferromagnetic anisotropic Heisenberg chain while it cannot be done in the ferromagnetic isotropic one. The average fidelity of the teleportation can be improved in the antiferromagnetic chains.
ABSENCE OF BCS CONDENSATION OF ATOMS IN A REPULSIVE FERMI GAS OF ATOMS
Authors: HAN FUXIANG , LI HAILING , LEI MINGHAO , WU E.
Published: January 2008

Bose–Einstein condensation of molecules and BCS condensation of Cooper pairs of atoms in an ultra-cold Fermi gas of atoms with a repulsive two-body interaction are studied by using the path integral representation of the grand partition function. From the self-consistent equations obtained in the present work for the order parameters, we have found that BCS condensation of atoms cannot occur in such a Fermi gas of atoms and that the condensate observed experimentally is composed of condensed molecules or possibly of preformed Cooper pairs. To substantiate our conclusions from the self-consistent equations for the order parameters, the effective atom–atom interaction mediated through molecules has also been computed with the Foldy–Wouthuysen transformation and has been found to be repulsive, which implies a net repulsive two-body interaction between atoms and hence the absence of BCS condensation of atoms.
VTS ZATOKA RADAR SYSTEM RELIABILITY AND AVAILABILITY ANALYSIS
Authors: BUDNY TYMOTEUSZ
Published: January 2008

In the paper we calculate reliability of radar system in Vessel Traffic Services Zatoka. Reliability and availability of the system were calculated on the base of reliability of the system components. There was assumed that system is a series-"m out of n". Conclusion is that appropriate evaluation of system reliability and availability is decisive in choosing service support location.
COLLECTION AND ANALYSIS OF CLIMATIC MEASUREMENTS FOR THE ASSESSMENT OF SNOW LOADS ON STRUCTURES
Authors: SADOVSKÝ ZOLTÁN , FAŠKO PAVOL , PECHO JOZEF , BOCHNÍČEK OLIVER , MIKULOVÁ KATARÍNA , ŠŤASTNÝ PAVEL
Published: January 2008

Climatological measurements for the assessment of snow loads on structures as practiced in Slovakia are discussed in the light of methodologies described in the relevant backgrounds to Eurocodes. The database of yearly snow load maxima based on the weekly measurements of water equivalent of snow cover on 660 rain-gauge stations in Slovakia recorded during the last 52 winter seasons is analyzed. Special interest is focused on the influence of heavy snowfalls in the winters 2004/2005 and 2005/2006, particularly on the extreme cases observed.
ADOPTED ISOCHRONE METHOD IMPROVING SHIP SAFETY IN WEATHER ROUTING WITH EVOLUTIONARY APPROACH
Authors: SZLAPCZYNSKA JOANNA , SMIERZCHALSKI ROMAN
Published: January 2008

The paper is focused on adaptation of an isochrone method necessary for application to a weather routing system with evolutionary approach. Authors propose an adaptation of the isochrone method with area partitioning assuring that the route found by the adopted method would not cross land. In result, when applied to a weather routing system with evolutionary approach, this proposal facilitates creation of initial population, resulting with routes of reduced collision risk and low costs of passage.
A THEORETICAL FRAMEWORK FOR MATRIX-BASED FEATURE EXTRACTION ALGORITHMS WITH ITS APPLICATION TO IMAGE RECOGNITION
Authors: FENG GUIYU , ZHANG DAVID , YANG JIAN , HU DEWEN
Published: January 2008

Recently proposed matrix-based methods, two-dimensional Principal Component Analysis (2DPCA), two-dimensional Linear Discriminant Analysis (2DLDA) and two-dimensional Locality Preserving Projections (2DLPP) have been shown to be effective ways to avoid the problems of high dimensionality and small sample sizes that are associated with vector-based methods. In this paper, we propose a general theoretical framework for matrix-based feature extraction algorithms from the point of view of graph embedding. Our framework can be applied to extend two recently proposed vector-based algorithms, i.e. Unsupervised Discriminant Projection (UDP) and Marginal Fisher Analysis (MFA) algorithms, to their matrix-based versions. Further, our framework can also be used as a platform to generate new matrix-based feature extraction algorithms by designing meaningful graphs, e.g. two-dimensional Discriminant Embedding Analysis (2DDEA) in this paper. It is shown that 2DLDA is actually a special case of the 2DDEA method. Experiments on three publicly available image databases demonstrate the effectiveness of the proposed algorithm. Our results fit into the scene for a better picture about the matrix-based feature extraction algorithms.
NOISE REMOVAL FOR MEDICAL X-RAY IMAGES IN MULTIWAVELET DOMAIN
Authors: LU JIANMING , WANG LING , LI YEQIU , YAHAGI TAKASHI
Published: January 2008

When a signal is embedded in an additive Gaussian noise, its estimation is often done by finding a wavelet basis that concentrates the signal energy over few coefficients and by thresholding the noisy coefficients. However, in many practical problems such as medical X-ray image, astronomical and low-light images, the recorded data is not modeled by Gaussian noise but as the realization of a Poisson process. Multiwavelet is a new development to the body of wavelet theory. Multiwavelet simultaneously offers orthogonality, symmetry and short support which are not possible in scalar 2-channel wavelet systems. After reviewing this recently developed theory, a new theory and algorithm for denoising medical X-ray images using multiwavelet multiple resolution analysis (MRA) are presented and investigated in this paper. The proposed covariance shrink (CS) method is used to threshold wavelet coefficients. The form of thresholds is carefully formulated which is the key to more excellent results obtained in the extensive numerical simulations of medical image denoising compared to conventional methods.
DOCUMENT SKEW DETECTION — A NOVEL APPROACH
Authors: MANJUNATH A. V. N. , HEMANTHA K. G. , NOUSHATH S.
Published: January 2008

In this paper, we propose a novel skew estimation technique for binary document images based on Boundary Growing Method (BGM), thinning and moments. BGM helps in extracting the text line blocks from the document. Thinning1 is performed to fit the best line for extracted text line blocks. Further, skew is computed for thinned line using second order moments. Several experiments have been conducted on various types of documents such as documents containing south Indian languages, English documents, journals, text with picture, noisy images, and document with different fonts and resolutions, to reveal the robustness of the proposed method. Based on the experimental results we have realized that the proposed method outperforms existing methods both in terms of mean and standard deviation.
ACCELERATING 3D NON-RIGID REGISTRATION USING GRAPHICS HARDWARE
Authors: COURTY NICOLAS , HELLIER PIERRE
Published: January 2008

There is an increasing need for real-time implementation of 3D image analysis processes, especially in the context of image-guided surgery. Among the various image analysis tasks, non-rigid image registration is particularly needed and is also computationally prohibitive. This paper presents a GPU (Graphical Processing Unit) implementation of the popular Demons algorithm using a Gaussian recursive filtering. Acceleration of the classical method is mainly achieved by a new filtering scheme on GPU which could be reused in or extended to other applications and denotes a significant contribution to the GPU-based image processing domain. This implementation was able to perform a non-rigid registration of 3D MR volumes in less than one minute, which corresponds to an acceleration factor of 10 compared to the corresponding CPU implementation. This demonstrated the usefulness of such method in an intra-operative context.
ROSE CURVE MODEL AND AN ANALYTICAL SOLUTION FOR ESTIMATING ITS PARAMETERS
Authors: ZOU JIE
Published: January 2008

In this short paper, we introduce a parameterized shape model, rose curve model. An analytical solution for estimating rose curve parameters from a binary silhouette or a probability map is derived. This analytical method finds the global optimum directly and therefore is fast and reliable. Two similarity invariant shape features, which measures the concavity and circular frequency of the shape can be derived from the six parameters of the rose curve. We apply the rose curve model to approximately segmenting flower images, primarily for testing the analytic parameter estimation method. Experiments on a database of 180 flower images from 30 species show that the rose curve is an excellent shape model for many flower species and the analytical parameter estimation method locates the flower regions well.
SERIES EXPANSIONS OF THE GENERALIZED K-BESSEL FUNCTIONS ON SYMMETRIC CONES
Authors: DING HONGMING , HE WEI
Published: January 2008

In this paper, we generalize the series expansion formula of classical K-Bessel functions to symmetric cones.
Proteases for Processing Proneuropeptides into Peptide Neurotransmitters and Hormones
Authors: Hook Vivian , Funkelstein Lydiane , Lu Douglas , Bark Steven , Wegrzyn Jill , Hwang Shin-Rong
Published: January 2008

Peptide neurotransmitters and peptide hormones, collectively known as neuropeptides, are required for cell-cell communication in neurotransmission and for regulation of endocrine functions. Neuropeptides are synthesized from protein precursors (termed proneuropeptides or prohormones) that require proteolytic processing primarily within secretory vesicles that store and secrete the mature neuropeptides to control target cellular and organ systems. This review describes interdisciplinary strategies that have elucidated two primary protease pathways for prohormone processing consisting of the cysteine protease pathway mediated by secretory vesicle cathepsin L and the well-known subtilisin-like proprotein convertase pathway that together support neuropeptide biosynthesis. Importantly, this review discusses important areas of current and future biomedical neuropeptide research with respect to biological regulation, inhibitors, structural features of proneuropeptide and protease interactions, and peptidomics combined with proteomics for systems biological approaches. Future studies that gain in-depth understanding of protease mechanisms for generating active neuropeptides will be instrumental for translational research to develop pharmacological strategies for regulation of neuropeptide functions. Pharmacological applications for neuropeptide research may provide valuable therapeutics in health and disease.
Private Global Business Regulation
Authors: Vogel David
Published: January 2008

Regulations that govern the social and environmental impacts of global firms and markets without state enforcement are a relatively new dimension of global business regulation. The growth of such voluntary “civil regulations” reflects both the expansion of legitimate authority in the global economy outside the state and the increasing use of alternative regulatory instruments to govern firms, including self-regulation, market-based instruments, and soft laws. In response to global social activism, many firms have adopted voluntary regulatory standards to avoid additional regulation and/or to protect their reputations and brands. Activists have targeted highly visible firms and have been willing to work cooperatively with them. The most important civil regulations are multi-stockholder codes, whose governance is shared by firms and nongovernmental organizations (NGOs), and which rely on product and producer certifications. Such codes face the challenge of acquiring legitimacy and of persuading both firms and NGOs of the value of their standards. The emergence of civil regulation addresses but does not resolve the challenge of making global firms and markets more effectively and democratically governed.
Effects of thyrotoxicosis and selective hepatic autonomic denervation on hepatic glucose metabolism in rats
Authors: Klieverik Lars P. , Sauerwein Hans P. , Ackermans Mariëtte T. , Boelen Anita , Kalsbeek Andries , Fliers Eric
Published: January 2008

Thyrotoxicosis is known to induce a broad range of changes in carbohydrate metabolism. Recent studies have identified the sympathetic and parasympathetic nervous system as major regulators of hepatic glucose metabolism. The present study aimed to investigate the pathogenesis of altered endogenous glucose production (EGP) in rats with mild thyrotoxicosis. Rats were treated with methimazole in drinking water and l-thyroxine (T4) from osmotic minipumps to either reinstate euthyroidism or induce thyrotoxicosis. Euthyroid and thyrotoxic rats underwent either a sham operation, a selective hepatic sympathetic denervation (Sx), or a parasympathetic denervation (Px). After 10 days of T4 administration, all animals were submitted to a hyperinsulinemic euglycemic clamp combined with stable isotope dilution to measure EGP. Plasma triiodothyronine (T3) showed a fourfold increase in thyrotoxic compared with euthyroid animals. EGP was increased by 45% in thyrotoxic compared with euthyroid rats and correlated significantly with plasma T3. In thyrotoxic rats, hepatic PEPCK mRNA expression was increased 3.5-fold. Relative suppression of EGP during hyperinsulinemia was 34% less in thyrotoxic than in euthyroid rats, indicating hepatic insulin resistance. During thyrotoxicosis, Sx attenuated the increase in EGP, whereas Px resulted in increased plasma insulin with unaltered EGP compared with intact animals, compatible with a further decrease in hepatic insulin sensitivity. We conclude that chronic, mild thyrotoxicosis in rats increases EGP, whereas it decreases hepatic insulin sensitivity. Sympathetic hepatic innervation contributes only to a limited extent to increased EGP during thyrotoxicosis, whereas parasympathetic hepatic innervation may function to restrain EGP in this condition.
Plasma potassium level is associated with common genetic variation in the β-subunit of the epithelial sodium channel
Authors: Gaukrodger Nicole , Avery Peter J. , Keavney Bernard
Published: January 2008

Plasma potassium is a moderately heritable phenotype, but no robust associations between common single nucleotide polymorphisms (SNPs) and plasma potassium have previously been described. Genetic influences on renal potassium handling could be important in the etiology of hypertension. We have tested whether common genetic variation in the gene encoding the β-subunit of the epithelial sodium channel (SCNN1B) affects plasma potassium and blood pressure level in a study of 1,425 members of 248 families ascertained on a proband with hypertension. We characterized family members for blood pressure using ambulatory monitoring, measured plasma potassium in venous blood samples, and genotyped four SNPs that spanned the SCNN1B gene. We found highly significant association between genotype at the SCNN1B rs889299 SNP situated in intron 4 of the gene and plasma potassium. Homozygotes for the rarer T allele had on average a 0.15 mM lower plasma potassium than homozygotes for the common C allele, with an intermediate value for heterozygotes (trend, P = 0.0003). Genotype at rs889299 accounted for ∼1% of the total variability in plasma potassium, or around 3% of the total heritable fraction. There was no association between genotype at any SCNN1B SNP and blood pressure considered as a quantitative trait, or with hypertension affection status. We have shown a modest sized but highly significant effect of common genetic variation in the SCNN1B gene on plasma potassium. Interaction between the rs889299 SNP and functional SNPs in other genes influencing aldosterone-responsive distal tubular electrolyte transport may be important in the etiology of essential hypertension.
Extracorporeal Blood Purification in Sepsis and Sepsis-Related Acute Kidney Injury
Authors: House Andrew A. , Ronco Claudio
Published: January 2008

Sepsis-related acute kidney injury (AKI) is an important complicating feature of sepsis, and is associated with greater complexity of care and higher mortality. Until recently, AKI lacked a standard, widely accepted definition, rendering it difficult to compare previously published strategies to prevent, recognize and treat this entity. Recently, the RIFLE classification of AKI has been developed, and confirmed in observational studies to be associated with subsequent morbidity and mortality. The management of sepsis-related AKI is evolving with new basic discoveries and ongoing translational clinical research, and will likely include nephroprotective strategies to protect kidneys in patients at risk, early recognition and amelioration of renal damage and pharmacological interventions to minimize injury and promote recovery. Furthermore, extracorporeal blood purification (EBP) has an important role to play, not only in the replacement of certain aspects of renal organ function such as acid-base/electrolyte homeostasis and extracellular fluid volume, but also in an immunomodulatory fashion. As a therapy that has the potential to influence the course of disease in sepsis, EBP in sepsis and sepsis-related AKI is the subject of this review.
Metabolic Syndrome and Kidney Disease
Authors: Ritz Eberhard
Published: January 2008

The clustering of cardiovascular risk factors was noted already a century ago, but it is only recently that a link between the CV risk cluster and insulin resistance has been postulated – a proposal which is not unanimously accepted. There is no doubt, however, that obesity per se impacts on renal function and the risk of chronic kidney disease (CKD). Particularly obesity early in life is an important predictor of CKD in adult life, but in adults as well a high body mass index (BMI) is an independent predictor of ESRD. The BMI threshold is lower in Asians. The link between obesity and CKD is not fully explained by the association between obesity and diabetes or hypertension respectively. Obesity is associated with increased glomerular filtration rate and renal blood flow, glomerulomegaly and in extreme cases focal segmental glomerulosclerosis. The causal role of obesity is underlined by the effect of weight loss on proteinuria and glomerular hyperfiltration. An even better predictor than BMI is visceral obesity (waist circumference). For kidney disease in the metabolic syndrome it is relevant that insulin resistance is linked to salt sensitivity and increased tubular reabsorption of sodium. Recent evidence points to adverse effects of aldosterone on podocytes, mediated by reactive oxygen species and resulting from hypothetical stimulants of aldosterone synthesis by visceral adipocytes.
Guidelines Have Done More Harm than Good
Authors: Amerling Richard , Winchester James F. , Ronco Claudio
Published: January 2008

Practice guidelines have proliferated in medicine but their impact on actual practice and outcomes is difficult, if not impossible, to quantify. Though guidelines are based largely on observational data and expert opinion, it is widely believed that adherence to them leads to improved outcomes. Data to support this belief simply does not exist. If guidelines are universally ignored, their impact on treatment and outcomes is minimal. The incorporation of guidelines into treatment protocols and performance measures, as is now common practice in nephrology, increases greatly the likelihood that guidelines will influence practice and hence, outcomes. Practice patterns set up this way may be resistant to change, should new evidence emerge that contradicts certain recommendations. Even if guidelines are entirely appropriate, a ‘one-size-fits-all’ approach is likely to benefit some, but not all. Certain patients may be harmed by adherence to specific guidelines. Guidelines certainly do not encourage clinicians to consider and treat each patient as an individual. They are unlikely to stimulate original research. They are created by a process that is artificial, laborious and cumbersome. This all but guarantees many guidelines are obsolete by the time they are published. Guidelines are produced with industry support and recommendations often have a major impact on sales of industry products.
Association between Erythropoietin Responsiveness and Body Composition in Dialysis Patients
Authors: Kotanko Peter , Thijssen Stephan , Levin Nathan W.
Published: January 2008

Background: In contrast to the general population, in maintenance hemodialysis (MHD) patients, small body size is correlated with reduced survival. The reasons for this association are unclear but may be related to a lower uremic toxin load relative to body weight and a higher distribution volume for uremic toxins in large patients. Since anemia is a salient feature in dialysis patients, this study aimed to explore the relationship between body composition and anemia control. Methods: Total adipose tissue (TAT), subcutaneous adipose tissue (SAT) and muscle mass (MM) were estimated by regression models in African-American MHD patients. Patients were grouped for further analysis by gender in tertiles of TAT, SAT, and MM. Analysis of covariance with age and serum albumin as covariates was employed to test for differences in hemoglobin (Hgb, g/dl), erythropoietin use (EPO, U/kg b.w./week), and EPO resistance index (ERI, U/kg b.w./week/Hgb). Results: 479 patients were studied (50.5% females). In both genders, EPO dose and ERI were lower the higher the tertile of TAT and SAT (all p < 0.02). In females, EPO and ERI were inversely related to tertiles of MM (p ≤ 0.001). No difference in Hgb concentration was observed. Conclusion: Anemia control is related to body composition in Black dialysis patients. EPO requirements and EPO resistance are reduced in patients with high TAT, SAT and MM (the latter in females only). A lower uremic load in large dialysis patients may contribute to these findings.
Present, Prevention, and Management of Chronic Kidney Disease in Latin America
Authors: Correa-Rotter Ricardo , Cusumano Ana María
Published: January 2008

In recent decades, Latin America (LA) has experienced profound demographic and epidemiologic changes conditioning an enormous increase in prevalence and incidence of chronic non-communicable diseases. End-stage renal disease has steadily increased in prevalence and incidence (478.2 and 168.7 pmp, respectively) and is emerging as a devastating medical, social, and economic problem for patients, families, and national health systems. The development of successful renal replacement treatment modalities has emphasized the wide breach in healthcare between developed and emerging nations. LA is composed of many nations that have a common social and cultural background yet exhibit significant variations in socioeconomic status, ethnicities, and human development. In addition, the region is experiencing a type 2 diabetes mellitus epidemic and a constant growth of related end-stage renal disease which at present is not sustainable and will be unaffordable in most countries, unless changes in public health policy and a new focus on the problem is generated. Renal transplantation, though increasing, cannot revert the growing prevalence. The development of public health policies and prevention programs is mandatory in LA and requires a better knowledge of prevalence and distribution of risk factors in the different nations of the region.
Medical Pluralism: Global Perspectives on Equity Issues
Authors: Marian Florica
Published: January 2008

Over the last decades, awareness has increased about the phenomenon of medical pluralism and the importance to integrate biomedicine and other forms of health care. The broad variety of healing cultures existing alongside biomedicine is called complementary or alternative medicine (CAM) in industrialized countries and traditional medicine (TM) in developing countries. Considerable debate has arisen about ethical problems related to the growing use of CAM in industrialized countries. This article focuses on equity issues and aims to consider them from a global perspective of medical pluralism. Several dimensions of equity are explored and their interrelatedness discussed: access to care, research (paradigm and founding) and recognition. This so-called ‘equity circle’ is then related to Iris Marion Young’s justice theory and particularly to the concepts of cultural imperialism, powerlessness and marginalisation.
New Insights into Growth Hormone Receptor Function and Clinical Implications
Authors: Lichanska A.M. , Waters M.J.
Published: January 2008

Although used as a therapeutic for 50 years, it is only recently that the application of molecular techniques has provided a basis for understanding growth hormone’s (GH) clinical actions. This article reviews progress in our current knowledge of the molecular mechanism of growth hormone (GH) receptor activation based on a number of physicochemical techniques, and documents insights gained into the means used by the activated GH receptor to control the expression of genes regulating growth and metabolism. These findings are related to disorders of short stature, and the therapeutic consequences are summarized.
Weight and Growth Requirements for Menarche in Teenage Girls with Eating Disorders, Weight Loss and Primary Amenorrhea
Authors: Swenne Ingemar
Published: January 2008

Background/Aim: To investigate weight and growth requirements for menarche in girls with eating disorders (ED), weight loss and primary amenorrhea. Methods: Growth charts from school health services and measurements of weight and stature throughout treatment were obtained for 47 such girls. Results: Weight loss started at an age of 12.4 ± 1.6 years from a top weight of 41.7 ± 7.1 kg. Approximately a year later they had lost 5.1 ± 4.3 kg and grown only 2.8 ± 3.5 cm. Following treatment and weight gain, growth accelerated and the girls reached a peak growth velocity of 4.3 ± 2.6 cm/year 2 years before menarche which occurred at an age of 15.5 ± 1.6 years at a weight of 52.2 ± 5.3 kg. Menarche occurred within a wide range of weights but could be predicted by a linear regression on prepubertal weight (R2 = 0.39; p < 0.001). Conclusions: Following treatment, girls with ED and primary amenorrhea progress through puberty at a slowed rate. The weight required for menarche can be predicted by the prepubertal weight which may represent the individual’s normal growth track unaffected by the ED.
Frequency of Cardiovascular Risk Factors in Obese Children and Adolescents Referred to a Tertiary Care Center in Israel
Authors: Shalitin S. , Phillip M.
Published: January 2008

Aims: To establish the frequency of dyslipidemia in obese Israeli children and adolescents and its association with other cardiovascular disease (CVD) risk factors. Methods: Files of 262 patients (5.1–18.8 years) with BMI >95th percentile for age and gender were reviewed for anthropometric and biochemical parameters of CVD risk. Dyslipidemia and hypertension were defined as cut-off point ≧95th percentile of healthy children. Results: Compared to patients with normal lipid profile, dyslipidemic patients (n = 71) had significantly higher prevalence of fatty liver (p < 0.001), higher percent body fat (males, p = 0.044), and higher C-reactive protein (females, p = 0.001). There was no significant difference in age, BMI-SDS, or familial CVD-related disorders. The hypertensive patients (n = 137) were significantly older than the normotensive patients (p < 0.001), had higher percent body fat (p = 0.008), larger waist circumference (p < 0.001), and higher HOMA-IR (p < 0.001). There were no significant between-group differences in BMI-SDS. The most significant factors associated with CVD risk were waist circumference and insulin level. Conclusions: Obese Israeli children have high rates of CVD risk factors, most of them unrelated to BMI-SDS or age. Therefore, we recommend screening for them in obese children with increased waist circumference of any age to detect those who require more intense interventions.
Low Serum IGF-I/GH Ratio Is Associated with Abnormal Glucose Tolerance in Acromegaly
Authors: Fukuoka Hidenori , Takahashi Yutaka , Iida Keiji , Kudo Takumi , Nishizawa Hitoshi , Imanaka Mari , Takeno Ryoko , Iguchi Genzo , Takahashi Kentaro , Okimura Yasuhiko , Kaji Hidesuke , Chihara Kazuo
Published: January 2008

Background/Aims: Acromegaly is frequently accompanied with impaired glucose tolerance (IGT) and diabetes mellitus (DM). It remains unclear which factors determine the abnormal glucose tolerance status in acromegaly. In addition, diverse actions of GH and IGF-I in regulating glucose metabolism in acromegaly have not yet been well elucidated. The aim of this study was to investigate the factors associated with abnormal glucose tolerance in acromegaly. Subjects and Study Design: We conducted a retrospective cross-sectional study that included 48 patients with active acromegaly. The subjects were divided into two groups by the results of 75 g OGTT: normal glucose tolerance (NGT) group (n = 19) and IGT+DM group (n = 29). Results: Systolic blood pressure (SBP) was significantly higher in the IGT+DM than in the NGT group. Homeostasis model assessment of β-cell function (HOMA-β) was significantly decreased in the IGT+DM group compared with the NGT group. Although serum GH or IGF-I levels were not different between the two groups, the IGF-I/GH ratio in the IGT+DM group was significantly lower than that in the NGT group. Conclusions: We have shown that a low serum IGF-I/GH ratio was associated with abnormal glucose tolerance in acromegaly. We propose that the IGF-I/GH ratio is a useful marker to understand the metabolic status in acromegaly.
Colo-Colonic Intussusception Caused by a Submucosal Lipoma
Authors: Twigt B.A. , Nagesser S.K. , Sonneveld D.J.A.
Published: January 2008

Adult intussusception is a rare clinical presentation and often not considered clinically in the differential diagnosis of adult patients with vague abdominal complaints. A 44-year-old woman visited our emergency department with sudden onset of intermittent abdominal pain. Diagnostic imaging revealed an intussusception caused by a submucosal lipoma of the sigmoid. A laparotomy was performed and the diagnosis was proven by histological examination. Submucosal lipomas are usually asymptomatic but may cause bleeding, obstruction, intussusception, or abdominal pain and thus mimic a malignancy. Surgical excision is indicated for symptomatic cases.
Three-Dimensional Melanin Distribution of Acral Melanocytic Nevi Is Reflected in Dermoscopy Features: Analysis of the Parallel Pattern
Authors: Kimoto M. , Sakamoto M. , Iyatomi H. , Tanaka M.
Published: January 2008

Background: Acral melanocytic nevi have parallel patterns on dermoscopy; however, it is not understood why pigment distributions exhibit such patterns. Aim: To clarify the reason why melanin distributions in acral melanocytic nevi exhibit a parallel pattern on dermoscopy. Methods: A serial sectioning perpendicular to the skin markings was performed, and each section was stained with modified Fontana-Masson staining to pick out melanin granules. These sections were then reconstructed to three-dimensional images by an image processing software, and these three-dimensional images were analyzed. Results: Melanin columns in the cornified layer were mainly seen in the dermoscopic images of acral melanocytic nevi. In the parallel-furrow pattern melanin columns were arranged vertically, and in the fibrillar pattern they were arranged in a slanting fashion. Conclusion: Melanin columns in the cornified layer, not melanin in the basal layer, mainly contribute to the dermoscopic pattern of acral melanocytic nevi.
Painful Wrinkles in the Bathtub: Association with Hyperhidrosis and Cystic Fibrosis
Authors: Seitz Cornelia S. , Gaigl Zeno , Bröcker Eva B. , Trautmann Axel
Published: January 2008

Transient aquagenic palmar hyperwrinkling (TAPH) is a rarely reported cutaneous condition clinically characterized by swelling and hyperwrinkling of the palms, and associated with burning sensations after briefly immersing the hands in water. Upon the withdrawal of water, the symptoms rapidly disappear. We report on a 10-year-old boy with type I diabetes, who developed the typical symptoms of TAPH concomitantly with the onset of palmar hyperhidrosis. Determination of the sodium chloride concentration of the sweat revealed elevated levels. Subsequent screening for the most common mutations of the gene responsible for cystic fibrosis (CF) was negative. Review of the literature shows that TAPH may develop in conditions of increased water absorption due to an increased sweat quantity, such as hyperhidrosis, or an increased sweat electrolyte concentration, such as CF. In the majority of reported cases TAPH has been associated with CF; therefore, it is a cutaneous sign, which should be recognized by dermatologists, and patients should be referred for evaluation of the sodium chloride concentration of the sweat.