Showing papers by "Cardiff University published in 2005"

Thermoelectrics Handbook : Macro to Nano

Abstract: GENERAL PRINCIPLES AND THEORETICAL CONSIDERATIONS General Principles and Basic Considerations D.M. Rowe Modern Thermodynamic Theory of Thermoelectricity L.I. Anatychuk and O.J. Luste Thermoelectric Phenomena under Large Temperature Gradients L.I. Anatychuk and L.P. Bulat Minority Carriers and Thermoelectric Effects in Bipolar Devices Kevin Pipe Effects of Charge Carriers' Interactions on Seebeck Coefficients David Emin Thermal Conductivity of Semiconductors with Complex Crystal Structure V.K. Zaitsev and M.I. Fedorov A Chemical Approach to the First-Principles Modeling of Novel Thermoelectric Materials Luca Bertini, Fausto Cargnoni, and Carlo Gatti Recent Trends for the Design and Optimization of Thermoelectric Materials: A Theoretical Perspective John S. Tse and Dennis D. Klug Thermoelectric Power Generation: Efficiency and Compatibility G. Jeffrey Snyder A New Upper Limit to the Thermoelectric Figure-of-Merit H.J. Goldsmid Thermoelectric Module Design Theories Gao Min Modeling and Characterization of Power Generation Modules Based on Bulk Materials Timothy P. Hogan and Tom Shih Energy Conversion Using Diode-Like Structures Yan Kucherov and Peter Hagelstein Size Effects on Thermal Transport Chandra Mohan Bhandari Thermoelectric Aspects of Strongly Correlated Electron Systems S. Paschen Theory and Modeling in Nanostructured Thermoelectrics Alexander A. Balandin Thermoelectric Power of Carbon Nanotubes G.D. Mahan Phonon-Drag Thermopower of Low-Dimensional Semiconductor Structures Yu.V. Ivanov MATERIAL PREPARATION AND MEASUREMENTS Solid State Synthesis of Thermoelectric Materials B.A. Cook and J.L. Harringa Review of Methods of Thermoelectric Materials Mass Production Yury M. Belov, Sergei M. Maniakin, and Igor V. Morgunov Structural Studies of Thermoelectric Materials Bo Brummerstedt Iversen Measurements of Resistivity and Thermopower: Principles and Practical Realization A.T. Burkov Electrical and Thermal Transport Measurement Techniques for Evaluation of the Figure-of-Merit of Bulk Thermoelectric Materials Terry M. Tritt Measurement of the Thermal Conductivity of Thin Films F. Voelklein, A. Meier, and M. Blumers Solvothermal Synthesis of Nanostructured Thermoelectric Materials X.B. Zhao, T.J. Zhu, and X.H. Ji Approaches to Thermoelectric Standardization E. Muller, C. Stiewe, D.M. Rowe, and S.G.K. Williams THERMOELECTRIC MATERIALS Thermoelectric Properties of Bismuth Antimony Telluride Solid Solutions H. Scherrer and S. Scherrer Bi-Sb Alloys: Thermopower in Magnetic Field V.M. Grabov and O.N. Uryupin Thermoelectrics on the Base of Solid Solutions of Mg2BIV Compounds (BIV = Si, Ge, Sn) V.K. Zaitsev, M.I. Fedorov, I.S. Eremin, and E.A. Gurieva Thermoelectric Properties of the Group V Semimetals J-P. Issi Thermoelectrics of Transition Metal Silicides M. Fedorov and V. Zaitsev Formation and Crystal Chemistry of Clathrates P. Rogl Structure, Thermal Conductivity and Thermoelectric Properties of Clathrate Compounds George S. Nolas Skutterudite-Based Thermoelectrics Ctirad Uher Oxide Thermoelectrics Kunihito Koumoto, Ichiro Terasaki, Tsuyoshi Kajitani, Michitaka Ohtaki, and Ryoji Funahashi Thermoelectric Properties of Electrically Conducting Organic Materials A.I. Casian Shifting the Maximum Figure-of-Merit of (Bi, Sb)2(Te, Se)3 Thermoelectrics to Lower Temperatures V.A. Kutasov, L.N. Lukyanova, and M.V. Vedernikov Functionally Graded Materials for Thermoelectric Applications V.L. Kuznetsov Recent Developments in Low Dimensional Thermoelectric Materials M.S. Dresselhaus and J.P. Heremans Thermoelectric Properties of Nanocrystalline Transition Metal Silicides J. Schumann and A.T. Burkov Nanostructured Skutterudites Mamoun Muhammed and Muhammet Toprak Thermal Conductivity of Nanostructured Thermoelectric Materials C. Dames and G. Chen THERMOELEMENTS, MODULES AND DEVICES Modeling and Optimization of Segmented Thermoelectric Generators for Terrestrial and Space Applications Mohamed S. El-Genk and Hamed H. Saber Thermocouple with a Passive HTSC Leg V.L. Kuznetsov and M.V. Vedernikov Anisotropic Thermoelements A.A. Snarskii and L.P. Bulat Miniaturized Thermoelectric Converters Harald Boettner, Joachim Nurnus, and Axel Schubert Thermoelectric Microelectromechanical Systems (MEMS) F. Voelklein and A. Meier Nanoscale Thermoelectrics Joachim Nurnus, Harald Boettner, and Armin Lambrecht Superlattice Thin-Film Thermoelectric Material and Device Technologies Rama Venkatasubramanian, Edward Siivola, and Brooks O'Quinn THERMOELECTRIC SYSTEMS AND APPLICATIONS Thermoelectric Power Generation System Recovering Industrial Waste Heat Takenobu Kajikawa The Concept of Thermoelectric Power Generation Topping-Up Co-Generation System Takenobu Kajikawa A Thermoelectric Application to Vehicles Kakuei Matsubara and Mitsuru Matsuura Thermoelectric Microgenerators with Isotope Heat Sources L.I. Anatychuk and A.A. Pustovalov Performance and Mass Estimates of CTM-ARPSs with Four GPHS Bricks Mohamed S. El-Genk and Hamed H. Saber Parametric and Optimization Analyses of Cascaded Thermoelectric-Advanced Radioisotope Power Systems with Four GPHS Bricks Mohamed S. El-Genk and Hamed H. Saber Space Missions and Applications Robert D. Abelson Quantum Well Thermoelectric Devices and Applications S. Ghamaty, J.C. Bass, and N.B. Elsner Thermoelectric Cooling of Electro-Optic Components V.A. Semenyuk Thermoelectric Refrigeration for Mass-Market Applications Montag C. Davis, Benjamin P. Banney, Peter T. Clarke, Brett R. Manners, and Robert M. Weymouth APPENDIX I: HISTORY OF THE INTERNATIONAL THERMOELECTRIC SOCIETY C.B. Vining, D.M. Rowe, J. Stockholm, and K.R. Rao APPENDIX II: SELECTED THERMOELECTRIC SOURCES

Living in a fungal world: impact of fungi on soil bacterial niche development⋆

Abstract: The colonization of land by plants appears to have coincided with the appearance of mycorrhiza-like fungi. Over evolutionary time, fungi have maintained their prominent role in the formation of mycorrhizal associations. In addition, however, they have been able to occupy other terrestrial niches of which the decomposition of recalcitrant organic matter is perhaps the most remarkable. This implies that, in contrast to that of aquatic organic matter decomposition, bacteria have not been able to monopolize decomposition processes in terrestrial ecosystems. The emergence of fungi in terrestrial ecosystems must have had a strong impact on the evolution of terrestrial bacteria. On the one hand, potential decomposition niches, e.g. lignin degradation, have been lost for bacteria, whereas on the other hand the presence of fungi has itself created new bacterial niches. Confrontation between bacteria and fungi is ongoing, and from studying contemporary interactions, we can learn about the impact that fungi presently have, and have had in the past, on the ecology and evolution of terrestrial bacteria. In the first part of this review, the focus is on niche differentiation between soil bacteria and fungi involved in the decomposition of plant-derived organic matter. Bacteria and fungi are seen to compete for simple plant-derived substrates and have developed antagonistic strategies. For more recalcitrant organic substrates, e.g. cellulose and lignin, both competitive and mutualistic strategies appear to have evolved. In the second part of the review, bacterial niches with respect to the utilization of fungal-derived substrates are considered. Here, several lines of development can be recognized, ranging from mutualistic exudate-consuming bacteria that are associated with fungal surfaces to endosymbiotic and mycophagous bacteria. In some cases, there are indications of fungal specific selection in fungus-associated bacteria, and possible mechanisms for such selection are discussed.

Comparison of overweight and obesity prevalence in school-aged youth from 34 countries and their relationships with physical activity and dietary patterns

Abstract: The purposes of this systematic review were to present and compare recent estimates of the prevalence of overweight and obesity in school-aged youth from 34 countries and to examine associations between overweight and selected dietary and physical activity patterns. Data consisted of a cross-sectional survey of 137 593 youth (10-16 years) from the 34 (primarily European) participating countries of the 2001-2002 Health Behaviour in School-Aged Children Study. The prevalence of overweight and obesity was determined based on self-reported height and weight and the international child body mass index standards. Logistic regression was employed to examine associations between overweight status with selected dietary and physical activity patterns. The two countries with the highest prevalence of overweight (pre-obese + obese) and obese youth were Malta (25.4% and 7.9%) and the United States (25.1% and 6.8%) while the two countries with the lowest prevalence were Lithuania (5.1% and 0.4%) and Latvia (5.9% and 0.5%). Overweight and obesity prevalence was particularly high in countries located in North America, Great Britain, and south-western Europe. Within most countries physical activity levels were lower and television viewing times were higher in overweight compared to normal weight youth. In 91% of the countries examined, the frequency of sweets intake was lower in overweight than normal weight youth. Overweight status was not associated with the intake of fruits, vegetables, and soft drinks or time spent on the computer. In conclusion, the adolescent obesity epidemic is a global issue. Increasing physical activity participation and decreasing television viewing should be the focus of strategies aimed at preventing and treating overweight and obesity in youth.

Incisional hernia: A 10 year prospective study of incidence and attitudes

Abstract: Five hundred and sixty-four patients reviewed 1 year after major abdominal surgery have been studied prospectively by a single observer for 10 years to determine the incidence and significance of incisional hernia. Of 337 (60 per cent) patients completing the 10 year follow-up 37 (11 per cent) developed an incisional hernia and 13 (35 per cent) of these first appeared at 5 years or later. One in three hernias caused symptoms. The late appearing hernias were smaller than the early ones, and caused little trouble. Of the 18 patients who consulted their general practitioner, 11 had symptoms and of these six (55 per cent) were referred for surgical opinion. Many hernias were diagnosed at routine outpatient follow-up and were likely to receive treatment from the surgeon. Most symptomatic patients were offered surgery with the remainder usually being offered a corset. In about half our patients (mainly those without symptoms) surgery was refused or advised against although the patients would have accepted it. Recurrence is common after surgical repair (40 per cent) but seems to be related to surgical technique. The possibility of complications occurring from an incisional hernia does not appear to be discussed with patients although obstruction occurred in 14 per cent of our patients with troublesome hernia.

Tunable gold catalysts for selective hydrocarbon oxidation under mild conditions

Abstract: Oxidation is an important method for the synthesis of chemical intermediates in the manufacture of high-tonnage commodities, high-value fine chemicals, agrochemicals and pharmaceuticals: but oxidations are often inefficient. The introduction of catalytic systems using oxygen from air is preferred for 'green' processing. Gold catalysis is now showing potential in selective redox processes, particularly for alcohol oxidation and the direct synthesis of hydrogen peroxide. However, a major challenge that persists is the synthesis of an epoxide by the direct electrophilic addition of oxygen to an alkene. Although ethene is epoxidized efficiently using molecular oxygen with silver catalysts in a large-scale industrial process, this is unique because higher alkenes can only be effectively epoxidized using hydrogen peroxide, hydroperoxides or stoichiometric oxygen donors. Here we show that nanocrystalline gold catalysts can provide tunable active catalysts for the oxidation of alkenes using air, with exceptionally high selectivity to partial oxidation products ( approximately 98%) and significant conversions. Our finding significantly extends the discovery by Haruta that nanocrystalline gold can epoxidize alkenes when hydrogen is used to activate the molecular oxygen; in our case, no sacrificial reductant is needed. We anticipate that our finding will initiate attempts to understand more fully the mechanism of oxygen activation at gold surfaces, which might lead to commercial exploitation of the high redox activity of gold nanocrystals.

At least 1 in 20 16S rRNA sequence records currently held in public repositories is estimated to contain substantial anomalies

Abstract: A new method for detecting chimeras and other anomalies within 16S rRNA sequence records is presented. Using this method, we screened 1,399 sequences from 19 phyla, as defined by the Ribosomal Database Project, release 9, update 22, and found 5.0% to harbor substantial errors. Of these, 64.3% were obvious chimeras, 14.3% were unidentified sequencing errors, and 21.4% were highly degenerate. In all, 11 phyla contained obvious chimeras, accounting for 0.8 to 11% of the records for these phyla. Many chimeras (43.1%) were formed from parental sequences belonging to different phyla. While most comprised two fragments, 13.7% were composed of at least three fragments, often from three different sources. A separate analysis of the Bacteroidetes phylum (2,739 sequences) also revealed 5.8% records to be anomalous, of which 65.4% were apparently chimeric. Overall, we conclude that, as a conservative estimate, 1 in every 20 public database records is likely to be corrupt. Our results support concerns recently expressed over the quality of the public repositories. With 16S rRNA sequence data increasingly playing a dominant role in bacterial systematics and environmental biodiversity studies, it is vital that steps be taken to improve screening of sequences prior to submission. To this end, we have implemented our method as a program with a simple-to-use graphic user interface that is capable of running on a range of computer platforms. The program is called Pintail, is released under the terms of the GNU General Public License open source license, and is freely available from our website at http://www.cardiff.ac.uk/biosi/research/biosoft/.

The multifarious, multireplicon Burkholderia cepacia complex

Abstract: The Burkholderia cepacia complex (Bcc) is a collection of genetically distinct but phenotypically similar bacteria that are divided into at least nine species. Bcc bacteria are found throughout the environment, where they can have both beneficial and detrimental effects on plants and some members can also degrade natural and man-made pollutants. Bcc bacteria are now recognized as important opportunistic pathogens that can cause variable lung infections in cystic fibrosis patients, which result in asymptomatic carriage, chronic infection or 'cepacia syndrome', which is characterized by a rapid decline in lung function that can include invasive disease. Here we highlight the unique characteristics of the Bcc, focusing on the factors that determine virulence.

Polarimetric observations of 15 active galactic nuclei at high frequencies: jet kinematics from bimonthly monitoring with the very long baseline array

Abstract: We present total and polarized intensity images of 15 active galactic nuclei obtained with the Very Long Baseline Array at 7 mm wavelength at 17 epochs from 1998 March to 2001 April. At some epochs the images are accompanied by nearly simultaneous polarization measurements at 3 mm, 1.35/0.85 mm, and optical wavelengths. Here we analyze the 7 mm images to define the properties of the jets of two radio galaxies, five BL Lac objects, and eight quasars on angular scales 0.1 mas. We determine the apparent velocities of 106 features in the jets. For many of the features we derive Doppler factors using a new method based on a comparison of the timescale of decline in flux density with the light-travel time across the emitting region. This allows us to estimate the Lorentz factors (Γ), intrinsic brightness temperatures, and viewing angles of 73 superluminal knots, as well as the opening angle of the jet for each source. The Lorentz factors of the jet flows in the different blazars range from Γ ~ 5 to 40 with the majority of the quasar components having Γ ~ 16–18, while the values in the BL Lac objects are more uniformly distributed. The brightest knots in the quasars have the highest apparent speeds, while the more slowly moving components are pronounced in the BL Lac objects. The quasars in our sample have similar opening angles and marginally smaller viewing angles than the BL Lacs. The two radio galaxies have lower Lorentz factors and wider viewing angles than the blazars. Opening angle and Lorentz factor are inversely proportional, as predicted by gasdynamical models. The brightness temperature drops more abruptly with distance from the core in the BL Lac objects than in the quasars and radio galaxies, perhaps owing to stronger magnetic fields in the former resulting in more severe synchrotron losses of the highest energy electrons. In nine sources we detect statistically meaningful deviations from ballistic motion, with the majority of components accelerating with distance from the core. In six sources we identify jet features with characteristics of trailing shocks that form behind the primary strong perturbations in jet simulations. The apparent speeds of these components increase with distance from the core, suggestive of acceleration of the underlying jet.

Directing transition from innate to acquired immunity: defining a role for IL-6.

Abstract: Appropriate control of leukocyte recruitment and activation is a fundamental requirement for competent host defense and resolving inflammation. A pivotal event that defines the successful outcome of any inflammatory event is the transition from innate to acquired immunity. In IL-6 deficiency, this process appears defective, and a series of in vivo studies have documented important roles for IL-6 in both the resolution of innate immunity and the development of acquired immune responses. Within this review, particular attention will be given to the regulatory properties of the soluble IL-6 receptor and how its activity may affect chronic disease progression.

A surgical instrument

Abstract: A device for morcellating tissue within a body cavity of a patient comprises a stationary tube (8) having a distal end portion (12), and a bipolar electrosurgical electrode assembly (13) located at the distal end of the tube. The electrosurgical electrode assembly (13) comprises first and second electrodes (14, 16) separated by an insulation member (15), the bipolar electrosurgical electrode assembly extending around the circumference of the distal edge of the tube (8). When an electrosurgical cutting voltage is applied to the electrode assembly (13), and relative movement is initiated between the tube (8) and the tissue, a core of severed tissue is formed within the tube such that it can be removed from the body cavity of the patient. A tissue-pulling device (2) such as a jaw assembly (24) can be employed to pull tissue against the distal end of the tube (8).

Theorizing the Micro-politics of Resistance: New Public Management and Managerial Identities in the UK Public Services:

Abstract: This article presents theoretical and empirical analysis of the micro-politics of resistance. We theorize resistance at the level of meanings and subjectivities, drawing attention to the multidirectional and generative effects in identity construction. We address two shortcomings present in much of the theorizing of resistance, namely, the conceptualizing of resistance as a set of actions and behaviours, and the narrow conception of resistance as a reaction to repressive power. Focusing on the UK public services, we draw from texts generated within interviews with public service professionals in the police, social services and secondary education to explore the meanings individuals ascribe to the discourse of New Public Management (NPM) and their positioning within these meanings. The analysis contributes to the study of organizations in three respects. First, it offers a more detailed and varied understanding of resistance that can account for different motivations and ways in which individuals struggle to transform meanings. Second, drawing on specific cases, it illustrates the process of the micro-politics of resistance. Third, it presents an empirically grounded understanding of the character and conduct of NPM that can accommodate greater complexity and nuance.

Green marketing: legend, myth, farce or prophesy?

Abstract: Purpose – To review the history of “green marketing” since the early 1990s and to provide a critique of both theory and practice in order to understand how the marketing discipline may yet contribute to progress towards greater sustainability. Design/methodology/approach – The paper examines elements of green marketing theory and practice over the past 15 years by employing the logic of the classic paper from 1985 “Has marketing failed, or was it never really tried” of seeking to identify “false marketings” that have hampered progress. Findings – That much of what has been commonly referred to as “green marketing” has been underpinned by neither a marketing, nor an environmental, philosophy. Five types of misconceived green marketing are identified and analysed: green spinning, green selling, green harvesting, enviropreneur marketing and compliance marketing. Practical implications – Provides an alternative viewpoint on a much researched, but still poorly understood area of marketing, and explains why the anticipated “green revolution” in marketing prefaced by market research findings, has not more radically changed products and markets in practice. Originality/value – Helps readers to understand why progress towards a more sustainable economy has proved so difficult, and outlines some of the more radical changes in thought and practice that marketing will need to adopt before it can make a substantive contribution towards greater sustainability.

Rapid stepwise onset of Antarctic glaciation and deeper calcite compensation in the Pacific Ocean

Abstract: The ocean depth at which the rate of calcium carbonate input from surface waters equals the rate of dissolution is termed the calcite compensation depth. At present, this depth is 4,500 m, with some variation between and within ocean basins. The calcite compensation depth is linked to ocean acidity, which is in turn linked to atmospheric carbon dioxide concentrations and hence global climate1. Geological records of changes in the calcite compensation depth show a prominent deepening of more than 1 km near the Eocene/Oligocene boundary ( 34 million years ago)2 when significant permanent ice sheets first appeared on Antarctica3, 4, 5, 6, but the relationship between these two events is poorly understood. Here we present ocean sediment records of calcium carbonate content as well as carbon and oxygen isotopic compositions from the tropical Pacific Ocean that cover the Eocene/Oligocene boundary. We find that the deepening of the calcite compensation depth was more rapid than previously documented and occurred in two jumps of about 40,000 years each, synchronous with the stepwise onset of Antarctic ice-sheet growth. The glaciation was initiated, after climatic preconditioning7, by an interval when the Earth's orbit of the Sun favoured cool summers. The changes in oxygen-isotope composition across the Eocene/Oligocene boundary are too large to be explained by Antarctic ice-sheet growth alone and must therefore also indicate contemporaneous global cooling and/or Northern Hemisphere glaciation.

Size-dependent effective elastic constants of solids containing nano-inhomogeneities with interface stress

Abstract: The fundamental framework of micromechanical procedure is generalized to take into account the surface/interface stress effect at the nano-scale. This framework is applied to the derivation of the effective moduli of solids containing nano-inhomogeneities in conjunction with the composite spheres assemblage model, the Mori–Tanaka method and the generalized self-consistent method. Closed-form expressions are given for the bulk and shear moduli, which are shown to be functions of the interface properties and the size of the inhomogeneities. The dependence of the elastic moduli on the size of the inhomogeneities highlights the importance of the surface/interface in analysing the deformation of nano-scale structures. The present results are applicable to analysis of the properties of nano-composites and foam structures.

Hypervalent iodine chemistry in synthesis: scope and new directions.

Abstract: The impressive development of hypervalent iodine chemistry in recent years is reflected by the number of publications in this area. Although the synthesis of the first hypervalent iodine compound dates back more than 100 years, the investigation of the reactivities of these compounds and their efficient use as metal-free reagents in organic synthesis is still ongoing. This contribution summarizes recent achievements and highlights key findings and developments that will influence future research and lead to novel applications of hypervalent iodine reagents in synthesis.

Geochemical mapping of the Mariana arc‐basin system: Implications for the nature and distribution of subduction components

Abstract: A new ICP-MS database for glasses from the Mariana Trough, together with published and new ICP-MS data from the Mariana arc, provides the basis for geochemical mapping of the Mariana arc-basin system. The geochemical maps presented here are based on the graphic representation of spatial variations in geochemical proxies for the principal mantle and subduction components. The focus is on three elements with high and similar partition coefficients but different behavior in subduction systems, namely, Ba, Th, and Nb. Two elements with different partition coefficients, Ta and Yb, are used as normalizing factors. Ratio maps (Ta/Yb, Nb/Ta, Th/Ta, Ba/Ta, Ba/Th) provide the simplest petrogenetic insights, subduction zone addition maps based on deviations from a MORB array provide more quantitative insights, and component maps represent an attempt to isolate the different subduction components. The maps shown here indicate the presence of a variably depleted asthenosphere and three added components: a Nb-Th-Ba component, a Th-Ba deep-subduction component, and a Ba-only shallow-subduction component. The asthenosphere entering the system is enriched relative to N-MORB and appears to be focused at three sites within the Mariana Trough. The Nb-Th-Ba component is present mainly in the north of the arc (the Northern Seamount province and northern Central Island Province), the northern edge of the Mariana Trough, and two locations within the Southern Seamount Province. It has a distinctively high Nb/Ta ratio and a moderate enrichment in Th and Ba relative to Nb. Its composition and distribution indicate that it may not be part of the present subduction system but instead originates in mantle lithosphere previously enriched above the subduction zone by addition of small-degree, subduction-modified mantle melts. The Th-Ba component is present throughout the arc and, in minor amounts, in parts of the back-arc basin. The Ba-only component is mainly present in the central part of the arc and at the edges of the back-arc basin. Overall, the geochemical maps provide a new perspective on the geochemical processes that accompany the evolution of an arc basin system from prerifting lithospheric enrichment, through arc-rifting to arc volcanism and back-arc spreading

Electrical generator and system

Abstract: An electrosurgical system includes a generator for generating radio frequency power, and an electrosurgical instrument including at least three electrodes and. The generator includes a radio frequency output stage having at least a pair of RF output lines, and a power supply coupled to the output stage for supplying power to the output stage. A controller is operable to limit the radio frequency output voltage developed across the output lines to at least a first predetermined threshold value to produce a cutting RF waveform, and a second threshold value to produce a coagulating RF waveform. In a combined mode, the controller delivers both cutting and coagulating waveforms, either simultaneously or by alternating constantly between the first and second threshold values to form a blended signal. The system also includes means for feeding the waveform to the three or more electrodes such that the cutting RF waveform is delivered between a first pair of the electrodes, and the coagulating waveform is delivered between a second pair of the electrodes.

The genetics of schizophrenia and bipolar disorder: dissecting psychosis

Abstract: Much work has been done to identify susceptibility genes in schizophrenia and bipolar disorder. Several well established linkages have emerged in schizophrenia. Strongly supported regions are 6p24–22, 1q21–22, and 13q32–34, while other promising regions include 8p21–22, 6q16–25, 22q11–12, 5q21–q33, 10p15–p11, and 1q42. Genomic regions of interest in bipolar disorder include 6q16–q22, 12q23–q24, and regions of 9p22–p21, 10q21–q22, 14q24–q32, 13q32–q34, 22q11–q22, and chromosome 18. Recently, specific genes or loci have been implicated in both disorders and, crucially, replicated. Current evidence supports NRG1, DTNBP1, DISC1, DAOA(G72), DAO, and RGS4 as schizophrenia susceptibility loci. For bipolar disorder the strongest evidence supports DAOA(G72) and BDNF. Increasing evidence suggests an overlap in genetic susceptibility across the traditional classification systems that dichotomised psychotic disorders into schizophrenia or bipolar disorder, most notably with association findings at DAOA(G72), DISC1, and NRG1. Future identification of psychosis susceptibility genes will have a major impact on our understanding of disease pathophysiology and will lead to changes in classification and the clinical practice of psychiatry.

A revised tropical to subtropical Paleogene planktonic foraminiferal zonation

Abstract: New biostratigraphic investigations on deep sea cores and outcrop sections have revealed several shortcomings in currently used tropical to subtropical Eocene plank­ tonic foraminiferal zonal schemes in the form of: 1) mod­ ified taxonomic concepts, 2) modifiel:l/different ranges of taxa, and 3) improved calibrations with magnetostratig­ raphy. This new information provides us with an op­ portunity to make some necessary improvements to ex­ isting Eocene biostratigraphic schemes. At the same time, we provide an alphanumeric notation for Paleo­ gene zones using the prefix 'P' (for Paleocene), 'E' (for Eocene) and '0' (for Oligocene) to achieve consistency with recent short-hand notation for other Cenozoic zones (Miocene ['M'], Pliocene [PL] and Pleistocene [PTD. Sixteen Eocene (E) zones are introduced (or nomen­ claturally emended) to replace the 13 zones and subzones of Berggren and others (1995). This new zonation serves as a template for the taxonomic and phylogenetic studies in the forthcoming Atlas of Eocene Planktonic Forami­ nifera (Pearson and others, in press). The 10 zones and subzones of the Paleocene (Berggren and others, 1995) are retained and renamed and/or emended to reflect im­ proved taxonomy and an updated chronologic calibra­ tion to the Global Polarity Time Scale (GPTS) (Berggren and others, 2000).' The PaleocenelEocene boundary is correlated with the lowest occurrence (LO) of Acarinina sibaiyaensis (base of Zone El), at the top of the trun­ cated and redefined (former) Zone P5. The five-fold zonation of the Oligocene (Berggren and others, 1995) is modified to a six-fold zonation with the elevation of (former) Subzones P21a and P21b to zonal status. The Oligocene (0) zomil' components are re­ named and/or nomenclaturally emended.

Selection of K in K-means clustering:

Abstract: The K-means algorithm is a popular data-clustering algorithm. However, one of its drawbacks is the requirement for the number of clusters, K, to be specified before the algorithm is applied. This paper first reviews existing methods for selecting the number of clusters for the algorithm. Factors that affect this selection are then discussed and a new measure to assist the selection is proposed. The paper concludes with an analysis of the results of using the proposed measure to determine the number of clusters for the K-means algorithm for different data sets.

Understanding the symptoms of the common cold and influenza

Abstract: The common cold and influenza (flu) are the most common syndromes of infection in human beings. These diseases are diagnosed on symptomatology, and treatments are mainly symptomatic, yet our understanding of the mechanisms that generate the familiar symptoms is poor compared with the amount of knowledge available on the molecular biology of the viruses involved. New knowledge of the effects of cytokines in human beings now helps to explain some of the symptoms of colds and flu that were previously in the realm of folklore rather than medicine—eg, fever, anorexia, malaise, chilliness, headache, and muscle aches and pains. The mechanisms of symptoms of sore throat, rhinorrhoea, sneezing, nasal congestion, cough, watery eyes, and sinus pain are discussed, since these mechanisms are not dealt with in any detail in standard medical textbooks.