bluuebunny/crossref_metadata_2025 huggingface dataset:
Implementing a dynamical ammonia emission parameterization in the large‐scale air pollution model ACDEP
Authors: Ambelas Skjøth Carsten , Hertel Ole , Gyldenkærne Steen , Ellermann Thomas
Published: March 2004

Currently, very simple parameterizations for the seasonal variation of the ammonia (NH3) emissions are used in most air pollution models. This limits the capability to reproduce observed seasonal variations in the NH3 concentrations in rural regions with agricultural activity. A dynamical parameterization of the temporal variation of NH3 emission for application into air pollution models has therefore been proposed. The obtained improvements are demonstrated by implementing a dynamical NH3 emission parameterization into the large‐scale air pollution model ACDEP. Meteorology, information about agricultural practice, and a simple crop growth model are the basis for the parameterization. Fifteen additive functions are used to describe the different parts of the NH3 emissions from agriculture, and a 16th function is used to describe NH3 emission from catalysts used in road traffic. The new parameterization is tested by comparison of model results with NH3 measurements from Danish monitoring stations situated in agricultural areas during the years 1999–2001. Improvements in correlation coefficient of calculated diurnal mean concentrations from 0.42 to 0.70 have been achieved, and a monthly correlation coefficient up to 0.98 has been obtained for the Tange station in 2000. This validation shows that the new parameterization gives a substantial improvement in the model calculations of the NH3 concentrations in areas with high agricultural activities. Finally, the validation showed that optimum results are obtained by including a temperature correction on the gauss functions representing the emission sources.
Enhancements in lower stratospheric CH3CN observed by the Upper Atmosphere Research Satellite Microwave Limb Sounder following boreal forest fires
Authors: Livesey Nathaniel J. , Fromm Michael D. , Waters Joe W. , Manney Gloria L. , Santee Michelle L. , Read William G.
Published: March 2004

On 25 August 1992, the Microwave Limb Sounder (MLS) on the Upper Atmosphere Research Satellite observed a significant enhancement in the abundance of lower stratospheric methyl cyanide (CH3CN) at 100–68 hPa (∼16–19 km altitude) in a small region off the east coast of Florida. The enhancement was seen to decay and move generally westward over ∼6 days. Concentrations up to ∼1500 parts per trillion by volume (pptv) were observed, compared to a typical stratospheric background level of 30 pptv. Aerosol index data from the Nimbus 7 Total Ozone Mapping Spectrometer (TOMS) instrument, together with trajectory calculations, provide strong evidence that the enhancement arose from the stratospheric injection, associated with strong thunderstorms, of tropospheric air with high CH3CN concentrations, originating in regions of extensive forest fire activity in Idaho (not observed by MLS in this period because of orbital geometry). After being lofted into the lower stratosphere, this air was advected into the regions observed by MLS and subsequently dispersed. These MLS enhanced CH3CN observations add to the growing body of evidence for the occurrence of such episodic injections of tropospheric air into the stratosphere.
Molecular composition of the water‐soluble fraction of atmospheric carbonaceous aerosols collected during ACE‐Asia
Authors: Mader B. T. , Yu J. Z. , Xu J. H. , Li Q. F. , Wu W. S. , Flagan R. C. , Seinfeld J. H.
Published: March 2004

During the Asian Pacific Regional Aerosol Characterization Experiment (ACE‐Asia), samples of carbonaceous aerosols were collected on board the Center for Interdisciplinary Remotely Piloted Aircraft Studies (CIRPAS) De Havilland DHC‐6 Twin Otter aircraft. The samples were analyzed to determine their total carbon (TC) and water‐soluble organic compound (WSOC) contents as well as to identify the individual compounds comprising the WSOC fraction of the aerosol. The TC concentrations varied from 3.5 to 14.3 μg C m−3; the highest TC levels were observed for samples collected in pollution layers that originated over mainland China. WSOC concentrations ranged from 0.54 to 7.2 μg C m−3, with the WSOC fraction contributing from 10 to 50% of the carbon mass. About 50% of the carbonaceous aerosol mass in pollution layers could be attributed to WSOC. For samples collected in dust layers the WSOC fraction of TC was much lower than that observed in pollution layers. The sum of all the detected organic ions accounted for 6.9–19% of the WSOC. In the six samples collected by the Twin Otter during ACE‐Asia, of the organic ions identified in the WSOC fraction, oxalate had the highest concentration. Samples collected from pollution layers exhibited a slightly higher ratio of formate to oxalate as compared to the other samples. Two samples had a relatively high ratio of lactate to oxalate, which might be a signature of some currently unidentified source of carbonaceous aerosol. The sum of the masses of sulfate and nitrate ions exceeded the sum of the masses of the identified organic ions by a factor of 9 to 17. The chemical levoglucosan, a tracer for biomass burning, comprised from 0.1 to 0.4% of TC mass. Comparing this ratio to the ratio measured directly in wood‐burning studies it was determined that biomass burning may have represented from ≈2 to 10% of the carbonaceous aerosol collected during ACE‐Asia.
MGS Radio Science electron density profiles: Interannual variability and implications for the Martian neutral atmosphere
Authors: Bougher S. W. , Engel S. , Hinson D. P. , Murphy J. R.
Published: March 2004

Martian electron density profiles provided by the Mars Global Surveyor (MGS) Radio Science (RS) experiment over the 95–200 km altitude range indicate wthat the height of the electron peak and the longitudinal structure of the peak height are sensitive indicators of the physical state of the Mars lower and upper atmospheres. The present analysis is carried out on five sets of occultation profiles, all at high solar zenith angles (SZA). Variations spanning 2 Martian years are investigated near aphelion conditions at high northern latitudes (64.7–77.6N) making use of four of these data sets. A mean ionospheric peak height of 133.5–135 km is obtained near SZA = 78–82°; a corresponding mean peak density of 7.3–8.5 × 104 cm−3 is also measured during solar moderate conditions at Mars. Strong wave number 2–3 oscillations in peak heights are consistently observed as a function of longitude over the 2 Martian years. These observed ionospheric features are remarkably similar during aphelion conditions 1 Martian year apart. This year‐to‐year repeatability in the thermosphere‐ionosphere structure is consistent with that observed in multiyear aphelion temperature data of the Mars lower atmosphere [Clancy et al., 2000; Smith, 2004]. Coupled Mars general circulation model (MGCM) and Mars thermospheric general circulation model (MTGCM) codes are run for Mars aphelion conditions, yielding mean and longitude variable ionospheric peak heights that reasonably match RS observations. A tidal decomposition of MTGCM thermospheric densities shows that observed ionospheric wave number 3 features are linked to a nonmigrating tidal mode with semidiurnal period (σ = 2) and zonal wave number 1 (s = −1) characteristics. The height of this photochemically determined ionospheric peak should be monitored regularly.
The first terrestrial analogue to Martian dust devil tracks found in Ténéré Desert, Niger
Authors: Rossi Angelo Pio , Marinangeli Lucia
Published: March 2004

The first example of terrestrial dust devil tracks is presented in this paper. Tracks found in Ténéré Desert, Niger are formed by transient events not related to regional winds. Compared to the Martian tracks, Ténéré tracks are generally longer and show higher average density. We interpreted these differences as due to different intensities of the dust devil vortices combined with different surface properties. We also suggest that grain size distribution and sorting of surface material is crucial to allow track formation. Major surface changes of Ténéré tracks have been observed in selected areas over a time span of 2 years, confirming the very low preservation potential of the tracks. However, no clear evidence for seasonal variations has been found on the available dataset. The Ténéré Desert represents a unique site to study the formation and evolution of these peculiar features and to compare their behavior on other planets.
Absolute determination of the asymmetry of the in-plane deformation of GaAs (001)
Authors: Largeau L. , Patriarche G. , Glas F. , Le Bourhis E.
Published: March 2004

Nanoindentation tests performed on GaAs (001) surfaces and on 4° misoriented GaAs (001) surfaces have led to the creation of anisotropic rosette arms lying along the 〈110〉 in-plane directions. One arm is always more elongated and constituted by perfect dislocations only while the shorter one shows in addition partial dislocations. Annealing of the deformed samples at 500 °C modifies the arrangement of the dislocations in the rosette arms but the asymmetry remains. Using a convergent beam electron diffraction method on plan views images obtained from indented (001) surfaces, we have determined the polarity of the samples. Experimental patterns were compared with simulated ones. The influences of several parameters were investigated and are discussed with particular attention addressed to the thickness of the samples. Before and after annealing, the longer rosette arm is constituted by α dislocations. The partial dislocations contained in the shorter rosette arm before annealing are of β type.
Roles of hydrogen dilution on the microstructural and optoelectronic properties of B-doped nanocrystalline Si:H thin films
Authors: Gullanar M. H. , Chen H. , Wei W. S. , Cui R. Q. , Shen W. Z.
Published: March 2004

We report on the roles of hydrogen dilution on the microstructural and optoelectronic properties of boron-doped nanocrystalline silicon thin films grown by plasma-enhanced chemical vapor deposition on glass substrates, through x-ray diffraction, scanning electron microscope, Raman scattering, optical transmission, temperature-dependent dark conductivity, and elastic recoil detection analysis (ERDA) measurements. The grain size, crystallinity, absorption coefficient, refractive index, and conductivity are found to decrease basically with increasing hydrogen dilution ratio ΔH. The Tauc’s optical band gap is found to increase with ΔH due to the quantum size effect. By the aid of hydrogen ion bombardment effect [J. Appl. Phys. 93, 1262 (2003)] as well as the hydrogen-induced annealing effect, the clear increase of hydrogen content with ΔH and the different hydrogen distribution from ERDA help us to elucidate the correlation of hydrogen dilution with the crystallinity and grain size. The argument has been further supported by a simple absorption model and the yielded refractive index and absorption coefficient.
Effects of implantation temperature on damage accumulation in Al-implanted 4H–SiC
Authors: Zhang Y. , Weber W. J. , Jiang W. , Wang C. M. , Shutthanandan V. , Hallén A.
Published: March 2004

Damage accumulation in 4H–SiC under 1.1 MeV Al22+ irradiation is investigated as a function of dose at temperatures from 150 to 450 K. Based on Rutherford backscattering spectroscopy and nuclear reaction analysis channeling spectra, the damage accumulation on both the Si and C sublattices have been determined, and a disorder accumulation model has been fit to the data. The model fits indicate that defect-stimulated amorphization is the primary amorphization mechanism in SiC over the temperature range investigated. The temperature dependence of the cross section for defect-stimulated amorphization and the critical dose for amorphization indicate that two different dynamic recovery processes are present, which are attributed to short-range recombination and long-range migration of point defects below and above room temperature, respectively. As the irradiation temperature approaches the critical temperature for amorphization, cluster formation has an increasing effect on disorder accumulation, and ion flux plays an important role on the nature and evolution of disorder. Dislocation loops, which are mostly formed under high ion flux, act as sinks for point defects, thereby reducing the disorder accumulation rate.
Cation-vacancy-induced low coercive field in La-modified SrBi2Ta2O9
Authors: Noguchi Yuji , Miyayama Masaru , Oikawa Kenichi , Kamiyama Takashi
Published: March 2004

We studied the effects of La modification on the crystal structure and the ferroelectric polarization properties of SrBi2Ta2O9 (SBT). The Rietveld refinement of neutron powder diffraction demonstrated that La3+ substitution, preferentially at the Sr2+ site (perovskite A site), resulted in A-site vacancies for charge compensation. Polarization measurements revealed that La modification led to a much lower coercive field and a larger remanent polarization. The tilt angle of the TaO6 octahedra from the c axis remained constant, but La modification decreased the tilt angle along the polarization direction (the component along the a axis). The results for Ca-, Ba-, and Pb-substituted SBT, as well as La-modified SBT, indicated that the TaO6 octahedral tilt along the a axis is closely related to coercive field for the SBT system.
First-principles calculations for defects and impurities: Applications to III-nitrides
Authors: Van de Walle Chris G. , Neugebauer Jörg
Published: March 2004

First-principles calculations have evolved from mere aids in explaining and supporting experiments to powerful tools for predicting new materials and their properties. In the first part of this review we describe the state-of-the-art computational methodology for calculating the structure and energetics of point defects and impurities in semiconductors. We will pay particular attention to computational aspects which are unique to defects or impurities, such as how to deal with charge states and how to describe and interpret transition levels. In the second part of the review we will illustrate these capabilities with examples for defects and impurities in nitride semiconductors. Point defects have traditionally been considered to play a major role in wide-band-gap semiconductors, and first-principles calculations have been particularly helpful in elucidating the issues. Specifically, calculations have shown that the unintentional n-type conductivity that has often been observed in as-grown GaN cannot be attributed to nitrogen vacancies, but is due to unintentional incorporation of donor impurities. Native point defects may play a role in compensation and in phenomena such as the yellow luminescence, which can be attributed to gallium vacancies. In the section on impurities, specific attention will be focused on dopants. Oxygen, which is commonly present as a contaminant, is a shallow donor in GaN but becomes a deep level in AlGaN due to a DX transition. Magnesium is almost universally used as the p-type dopant, but hole concentrations are still limited. Reasons for this behavior are discussed, and alternative acceptors are examined. Hydrogen plays an important role in p-type GaN, and the mechanisms that underlie its behavior are explained. Incorporating hydrogen along with acceptors is an example of codoping; a critical discussion of codoping is presented. Most of the information available to date for defects and impurities in nitrides has been generated for GaN, but we will also discuss AlN and InN where appropriate. We conclude by summarizing the main points and looking towards the future.
Lattice thermal conductivity of K2(Bi1−zSbz)8Se13 solid solutions
Authors: Kyratsi Theodora , Hatzikraniotis Evripides , Paraskevopoulous M. , Dyck Jeffrey S. , Shin H. K. , Uher Ctirad , Kanatzidis Mercouri G.
Published: March 2004

The family of solid solutions of the type β-K2(Bi1−zSbz)8Se13 (0<z⩽1) was studied with respect to thermal conductivity as a function of temperature and stoichiometry. At low temperature, the variation of lattice thermal conductivity with composition shows a transition from a typical crystalline to glasslike behavior. Analysis of the high-temperature data shows a contribution due to the mixed occupation of Bi/Sb crystallographic sites as well as an additional contribution due to point defects.
Ellipsometric characterization of LaNiO3−x films grown on Si (111) substrates: Effects of oxygen partial pressure
Authors: Hu Z. G. , Huang Z. M. , Wu Y. N. , Zhao Q. , Wang G. S. , Chu J. H.
Published: March 2004

LaNiO 3−x films have been grown on Si (111) substrates under different oxygen partial pressures using radio frequency magnetron sputtering. X-ray diffraction shows that these films are polycrystalline with a highly (100)-preferential orientation. The optical properties of the LaNiO3−x films have been systematically investigated by spectroscopic ellipsometry (SE) in the wavelength range of 400–1700 nm. For interpreting the SE experimental data, a parametrized Drude and double Lorentzian oscillator dispersion relation has been used to model the optical response of the LaNiO3−x films. The relations between the optical constants of the LaNiO3−x films and oxygen partial pressure have been characterized in detail. The resistivity can be calculated by the Drude term and these ellipsometric analysis results are nearly consistent with the electrical dc measurements. The resistivity (these values are about 5.5×103 μΩ cm) obtained by spectroscopic ellipsometry shows that these films would be good to use as bottom electrodes.
Particle-induced erosion of materials at elevated temperature
Authors: Doerner R. P. , Krasheninnikov S. I. , Schmid K.
Published: March 2004

The experimentally measured erosion rate of surfaces exposed to energetic particle bombardment at an elevated temperature exceeds that predicted by a summation of the physical sputtering rate and the thermodynamic sublimation/evaporation rate. A model based on the creation of surface adatoms, due to the energetic projectile bombardment of surfaces, and their subsequent sublimation/evaporation is developed to explain the enhanced erosion. Molecular dynamics simulations of beryllium confirm that the experimentally measured evaporation energy is consistent with the binding energy of adatoms. Experimental data of temperature-dependent erosion from both solid (beryllium) and liquid (lithium) samples are in agreement with the radiation activated adatom sublimation model.
Optimization and analysis of NF3 in situ chamber cleaning plasmas
Authors: Ji Bing , Yang James H. , Badowski Peter R. , Karwacki Eugene J.
Published: March 2004

We report on the optimization and analysis of a dilute NF3 in situ plasma-enhanced chemical vapor deposition chamber cleaning plasma for an Applied Materials P-5000 DxL chamber. Using design of experiments methodology, we identified and optimized operating conditions within the following process space: 10–15 mol % NF3 diluted with helium, 200–400 sccm NF3 flow rate, 2.5–3.5 Torr chamber pressure, and 950 W rf power. Optical emission spectroscopy and Fourier transform infrared spectroscopy were used to endpoint the cleaning processes and to quantify plasma effluent emissions, respectively. The results demonstrate that dilute NF3-based in situ chamber cleaning can be a viable alternative to perfluorocarbon-based in situ cleans with added benefits. The relationship between chamber clean time and fluorine atom density in the plasma is also investigated.
Methodology Problems in Urban Governance Studies
Authors: Gissendanner Scott
Published: March 2004

Increasing attention has been paid to forms of urban governance, or how public and private sector actors cooperate in generating new policies. In fact, almost everywhere where urban governance structures have been looked for, they have been found. This apparent ubiquity of governance networks has ushered in a new era for urban studies, but it raises the issue of whether such structures vary and whether the differences can be measured and used in explaining other dimensions of city difference. The author argues that the ubiquity problem does not reflect a fatal deficit in urban governance concepts but is, rather, a correctable problem of methods. Urban governance research would benefit greatly from the more widespread use of existing descriptive methods and techniques which produce results that are easy to compare across cities, and thus expand the basis for inductive theory building. As the high cost of such methods discourages comparative research designs with multiple cases, a similar but more cost-effective research method—which has advantages and disadvantages—is discussed. The kinds of simple structural features of governance networks it reveals represent a new potential dimension of explanation in urban research.
Measuring Neighbourhood Deprivation: A Critique of the Index of Multiple Deprivation
Authors: Deas Iain , Robson Brian , Wong Cecilia , Bradford Michael
Published: March 2004

There is now a sustained interest in measuring geographical variation in social and economic circumstances in order to guide urban policy resource allocation decisions. The most recent attempt to measure local area deprivation in England has come through the government's Index of Multiple Deprivation (IMD). The authors aim to consider the degree to which the IMD provides a reliable mechanism for doing so and to suggest the ways in which its successors might best be refined. They argue that although the IMD, in many respects, represents a commendable advance in terms of the development of techniques to quantify deprivation, there remain significant limitations that future approaches could profitably address.
Addressing the Business Support Needs of Ethnic Minority Firms in the United Kingdom
Authors: Deakins David , Ram Monder , Smallbone David
Published: March 2004

The authors examine the provision of enterprise support to ethnic minority businesses (EMBs) in five cities in the United Kingdom. The central focus is on the nature of support provision, including relationship with the commercial banks. It is well established that EMBs are underrepresented as clients of mainstream providers of enterprise support, such as Business Links in England, or Local Enterprise Companies in Scotland, and that participation and practice, even with specialist ethnic agencies, is highly variable. The authors discuss evidence from research undertaken through a programme of thirty-three face-to-face interviews with respondents from a cross-section of support agencies in five city locations in which EMBs are concentrated, namely, London, Leicester, Birmingham, Glasgow, and Edinburgh. They discuss evidence from the face-to-face interviews in the light of previous research findings, developing implications for future support policy for EMBs. They highlight good practice, identify gaps in provision, and suggest policies which can improve the access of EMBs to support and finance.
Policy Support for Small Firms in Rural Areas: The English Experience
Authors: Smallbone David , Baldock Robert , North David
Published: March 2004

This paper is concerned with small business development in rural areas and the policy approaches currently being used to support them. The key question underlying the paper is the extent to which small businesses located in rural areas have distinctive support needs, associated with the characteristics of rural businesses themselves or their owners, and/or the characteristics of the external operating environment for business in rural areas. A related question concerns the possible influence of enterprise characteristics and the characteristics of rural areas on how the business support needs of rural businesses are best addressed. The study comprised a desk-based review of existing literature relevant to the support needs of rural enterprises and/or the means of addressing them. It also included primary research on policy initiatives and programmes concerned with enterprise development in rural areas. Telephone interviews were conducted in 2001 with representatives of Business Links with catchments that included rural areas, as well as other key agencies (for example, the Countryside Agency). In addition, twenty-four case studies were completed of rural policy initiatives, based on face-to-face interviews. Following a brief review of key literature, an overview of the policies currently being operated by Business Link is described, based on the survey. This is followed by an identification of good-practice principles of rural business support, based on an analysis of the case-study support initiatives. The paper concludes by identifying the implications of the analysis for future enterprise support policy.
Planning and Power: Towards an Emancipatory Planning Approach
Authors: Albrechts Louis
Published: March 2004

Planning is challenged to interrelate four different concepts of rationality: value, instrumental, communicative, and strategic. Working out an emancipatory planning approach needs to focus on conflict and power relations and needs communicative, people-centred, practices. Therefore, the author confronts dimensions in the broader planning process with systems of power. Besides planning literature, the author's experience in practice is used. In this way directions are provided for incorporating an explicit power strategy in planning and for the form it may take.
Phyto-oestrogens, their mechanism of action: current evidence for a role in breast and prostate cancer
Authors: Magee Pamela J. , Rowland Ian R.
Published: March 2004

The incidence of hormone-dependent cancers, such as those of the breast and prostate, is much lower in Eastern countries such as China and Japan in comparison with the Western world. Diet is believed to have a major effect on disease risk and one group of compounds, the phyto-oestrogens, which are consumed in large amounts in Asian populations, have been implicated in cancer protection. This view follows the finding that plasma and urinary levels of phyto-oestrogens are much higher in areas where cancer incidence is low in comparison with areas of high cancer incidence. The phyto-oestrogens are comprised of two main groups; the isoflavones and lignans. Of the isoflavones, genistein and daidzein have been the most widely studied. These compounds have been shown to possess anticancer properties; however their precise mechanism of action remains to be elucidated. In comparison, few studies have investigated the effects of lignans in breast and prostate cancer.In vitrostudies have shown that genistein exerts biphasic effects on cancer cell growth, stimulating growth at low concentrations (<10μM) and inhibiting growth at high concentrations (>10μM), which suggests that low phyto-oestrogen levels may stimulate cancer growthin vivo. Plasma phyto-oestrogen concentrations of >10μM cannot be achieved by dietary intake and therefore the timing of exposure to phyto-oestrogens may be of the utmost importance in determining their chemopreventive effects. The present paper reviews the effects of phyto-oestrogens on breast and prostate cancerin vivoandin vitroand discusses possible mechanisms of action via which these compounds may exert their effects.
Estimated intake of milk fat is negatively associated with cardiovascular risk factors and does not increase the risk of a first acute myocardial infarction. A prospective case–control study
Authors: Warensjö Eva , Jansson Jan-Håkan , Berglund Lars , Boman Kurt , Ahrén Bo , Weinehall Lars , Lindahl Bernt , Hallmans Göran , Vessby Bengt
Published: March 2004

Milk fat is high in saturated fatty acids (SFA) and high intakes of SFA are associated with cardiovascular diseases. The aim of the present study was to prospectively evaluate the potential risk of a first-ever acute myocardial infarction (AMI) in relation to the estimated milk-fat intake, reflected as the proportions of pentadecanoic acid (15:0) and heptadecanoic acid (17:0) in serum lipid esters. This was evaluated in a study population selected within the Västerbotten Intervention Program and the northern Sweden ‘Monitoring of Trends and Determinants in Cardiovascular disease’ survey populations. A prospective case–control design was used. The proportions of the biomarkers were lower in the cases (n78) than in the controls (n156), who were matched for age, sex, sampling time and geographical region. The standardised odds ratios of becoming an AMI case were between 0·7 and 0·8 for the biomarkers. The proportions of 15:0 and 17:0 in serum phospholipids were significantly and negatively correlated to serum concentrations of plasminogen activator inhibitor-1, tissue-type plasminogen activator, triacylglycerols, insulin, specific insulin, pro-insulin and leptin (allP<0·0001), suggesting a negative relationship to the insulin-resistance syndrome and the risk of CHD. Adjustment for BMI did not materially change the relationships. Although there seems to be a negative association between milk-fat intake as mirrored by the proportions of 15:0 and 17:0 in serum lipid esters and a first-ever AMI, adjustment for clinical risk factors removed this relationship.
Linoleate supplementation in steers modifies lipid composition of plasma lipoproteins but does not alter their fluidity
Authors: Scislowski Valérie , Durand Denys , Gruffat-Mouty Dominique , Motta Claude , Bauchart Dominique
Published: March 2004

The health value for man of lipids in bovine muscles can be improved by the addition of PUFA to the animals' diets, but such treatments can modify fluidity of plasma lipoproteins and therefore their metabolic functions. The aim of the present study was to analyse whether changes in chemical composition of lipoproteins in steers fed sunflower oil-rich diets altered lipoprotein fluidity, measured by fluorescence polarization and electron spin resonance. LDL, light HDL and heavy HDL fractions were isolated by ultracentrifugation from plasma of eighteen crossbred Charolais×Salers steers. For a period of 70d, animals were given a control diet (C,n6) consisting of hay (540g/kg) and concentrate mixture (460g/kg) or the same basal diet supplemented with sunflower oil rich inn-6 PUFA (40g/kg diet DM), given either as crushed seeds (S,n6) or as a free oil infused directly into the duodenum (O,n6), thus avoiding ruminal hydrogenation of PUFA. We have shown that in bovine animals: (1) fluidity measurements by fluorescence polarization must be made at the bovine physiological temperature (38·5°C); (2) heavy HDL always appear as the less fluid lipoparticles; (3) electron spin resonance, which does not depend on lipoparticle size, is more appropriate to compare the fluidity of LDL with that of light HDL. The values for lipoprotein fluidity measured by both methods indicated that linoleate-rich diets did not have any effect when compared with diet C; however, chemical variables support a fluidification of lipoparticles, since in steers given the diet O,n-6 PUFA concentrations increased in polar (×1·8) and neutral (×1·6) lipids in lipoparticles (P=0·0001). The phospholipid:protein ratio increased in light (+20%,P=0·019) and heavy (+23%,P=0·06) HDL and especially in LDL (+46%,P=0·0001); the total cholesterol:phospholipid ratio decreased in the three lipoprotein classes (−15 to −30%, NS). Diet S led to similar but less pronounced effects. We concluded that linoleate-rich diets modified the chemical composition of plasma lipoproteins in steers, but did not alter their fluidity; this probably occurred as a result of ‘homeoviscous adaptation’, which ensured their functional capacity.
Dietary sodium requirement determined for juvenile hybrid tilapia (Oreochromis niloticus × O. aureus) reared in fresh water and seawater
Authors: Shiau Shi-Yen , Lu Li-Shan
Published: March 2004

Two 8-week feeding trials were conducted to determine the dietary Na requirement for juvenile hybrid tilapia (Oreochromis niloticus × O. aureus) reared in fresh water and seawater. In each experiment, NaCl was added to the basal diet at 0, 0·5, 1, 2, 3, 5, or 7g Na/kg diet (fresh water) and at 0, 0·2, 0·5, 0·8, 1·2, 1·5, 2, or 3g Na/kg diet (seawater). Each diet was fed to three replicate groups of fish, individual fish initially weighing 0·69 (se 0·01) g, in a closed, recirculating rearing system. In fresh water, the tilapia fed the diet supplemented with 2g Na/kg diet had significantly (P<0·05) greater weight gain than the fish fed the diets supplemented with ≥3 and ≤0·5g Na/kg diet. Feed efficiency (FE) in fish generally followed the weight-gain pattern. Gill Na+–K+ ATPase activity was highest in the fish fed the diets supplemented with 1–3g Na/kg diet, followed by the fish fed the diet with 7g Na/kg diet and lowest in the fish fed the unsupplemented control diet. In seawater, the weight gain, FE and gill Na+–K+ ATPase activity in fish were not affected by the dietary treatment. Analysis by polynomial regression of weight gain, by broken-line regression of gill Na+–K+ ATPase activity and by linear regression of whole-body Na retention of the fish reared in fresh water, indicated that the adequate dietary Na concentration for tilapia is about 1·5g/kg diet. The present study also suggests that no dietary Na is required for tilapia reared in seawater.
Learning about cues that prevent an outcome: Conditioned inhibition and differential inhibition in human predictive learning
Authors: Karazinov Danielle M. , Boakes Robert A.
Published: March 2004

Summation tests were used to assess whether participants in a human predictive judgement task learned that some cues (foods) prevented the occurrence of the outcome (migraine). In three experiments the preventative effect of a conditioned inhibitor, I, trained in the design, P+, PI–, I–, was stronger than that of a negative control cue, N, that had been presented alone with the same frequency and simply predicted no outcome. This control cue, N, also passed the summation test when compared to a novel control cue. Experiments 2 and 3 examined whether the latter negative control effect was attributable to differential inhibition. Manipulations designed to alter context learning and the magnitude of the negative contingency did not affect the properties of the negative control cue. Thus, these experiments did not support the possibility that a cue given simple negative training acquires differential inhibition. Regardless of the mechanism underlying the negative control effect, the consistent finding that the conditioned inhibition cue, I, reduced prediction of the outcome more than did the negative control cue, N, provides evidence for true conditioned inhibition whose acquisition requires co-occurrence of the preventative cue with a positive training cue.
Superconditioning from a reduced reinforcer
Authors: Rescorla Robert A.
Published: March 2004

In four autoshaping experiments pigeons received conditioned inhibition training of the form A++, AB–, where ++ is a strong reinforcer and – is nonreinforcement. Subsequent AB+ training, in which + is a moderate reinforcer, resulted in enhanced conditioning of A, relative to an A stimulus receiving no treatment, one receiving A+ treatment, and one receiving A++ treatment. This enhancement of conditioning to A constitutes a demonstration of “superconditioning”. The presence of the inhibitory B sufficiently enhanced the reinforcing power of the moderate reinforcer (+) that it was able to further increase the excitation controlled by A. This occurred even though A had previously been paired with a stronger reinforcer (++). Superconditioning was also observed when A and B were extinguished prior to treatment with + or were originally neutral stimuli followed by + in the presence of an inhibitor trained elsewhere.
Neo-Bureaucracy and Public Management: The Case of Medicine in the National Health Service
Authors: Harrison Stephen , Smith Carole
Published: March 2004

Contemporary public service management in the UK is accompanied by discourses of the ‘third way’ and ‘new public management’ that claim to stand in contrast to older bureaucratic approaches based on hierarchy and rule-adherence. Our examination of approaches to the management of National Health Service medicine over the last twenty years suggests the reverse: that in this particular sector at least, there has been increasing bureaucratisation, though based on rules enforced by regulatory agencies rather than by hierarchical management. Drawing on a number of long-established literatures, we argue that this ‘neobureaucracy’ is likely to possess inadequate technical, political and behavioural capacities for what is expected of it.
Low Dose Histone Deacetylase Inhibitor, Depsipeptide (FR901228), Promotes Adenoviral Transduction in Human Rhabdomyosarcoma Cell Lines
Authors: Navid Fariba , Mischen Blaine T. , Helman Lee J.
Published: March 2004

Purpose. Transduction of rhabdomyosarcoma (RMS) cells with adenoviral vectors for in vivo and in vitro applications has been limited by the low to absent levels of coxackie and adenovirus receptor (CAR). This study investigates the potential use of low doses of a histone deacetylase inhibitor, depsipeptide (FR901228), currently in Phase II human trials, to enhance adenoviral uptake in six rhabdomyosarcoma cell lines.

Methods. Differences in adenoviral uptake in the presence and absence of depsipeptide (FR901228) were assessed using an adenoviral construct tagged with green fluorescent protein. Changes in CAR and αv integrin expression RMS in response to pretreatment with depsipeptide (FR901128) was determined using RT‐PCR.

Results. Pretreatment of five of six RMS cell lines with 0.5 ng/ml of depsipeptide (FR901228) for 72 h resulted in increased viral uptake as assessed by green fluorescent protein expression. RT‐PCR analysis for CAR showed that in four of these five cell lines, CAR expression was increased 2.8–8.1‐fold in cells treated with depsipeptide (FR901228) as compared to control. αv integrin expression was substantially increased in the one cell line, RH5, which showed increased GFP expression in response to depsipeptide (FR901228) pretreatment but a minimal increase in CAR expression.

Conclusions. Depsipeptide (FR901228) can be used as a vehicle to enhance adenoviral transduction in a majority of RMS cells. The mechanism of increased viral uptake appears to mediate via upregulation of CAR.
Osteosarcoma Associated With Diamond‐Blackfan Anaemia: A Case of a Child Receiving Growth Hormone Therapy
Authors: Lee Robert S. , Higgs Deborah , Haddo Omar , Pringle Jean , Briggs Timothy W. R.
Published: March 2004

Purpose: Diamond–Blackfan anaemia (DBA) is a rare pure congenital red cell aplasia, usually presenting in infancy or early childhood. The literature suggests a predisposition to haemopoietic malignancy but in addition solid tumours have been reported, with five cases of osteosarcoma described.

Patient: A sixth case of a 12‐year‐old girl with DBA who developed an osteosarcoma of the distal femur is presented.

Results: She was treated with methotrexate followed by tumour excision and distal femoral replacement. The patient is currently alive with multiple pulmonary metastases.

Discussion: We discuss the association between the administration of growth hormone and future development of malignancy in patients with DBA.
On the Metaphysics of Species*
Authors: Crane Judith K.
Published: March 2004

This paper explains the metaphysical implications of the view that species are individuals (SAI). I first clarify SAI in light of the separate distinctions between individuals and classes, particulars and universals, and abstract and concrete things. I then show why the standard arguments given in defense of SAI are not compelling. Nonetheless, the ontological status of species is linked to the traditional “species problem,” in that certain species concepts do entail that species are individuals. I develop the idea that species names are rigid designators and show how this provides additional motivation for SAI.
Open access: a medical association perspective
Authors: Banks Peter
Published: March 2004

The benefits claimed for open access publishing in the medical area are subjected to evaluation and question. It is represented that these benefits are, in many cases, illusory or doubtful.
Open access publishing models: opportunity or threat to scholarly and academic publishers?
Authors: Lamb Christine
Published: March 2004

Various models of open access publishing and new initiatives are reviewed through the published literature with recommended strategies for traditional journal publishers.
Scholarly communication trends — voices from the vortex: a summary of specialist opinion
Authors: Davies J. Eric , Greenwood Helen
Published: March 2004

The views of specialists (academics, librarians, publishers and information scientists) on trends in scholarly communications were canvassed by means of structured questions. A greater commonality of views was found than might have been expected.
Cerebral Ischemia and Reperfusion: The Pathophysiologic Concept as a Basis for Clinical Therapy
Authors: Schaller Bernhard , Graf Rudolf
Published: March 2004

The ischemic penumbra has been documented in the laboratory animal as severely hypoperfused, nonfunctional, but still viable brain tissue surrounding the irreversibly damaged ischemic core. Saving the penumbra is the main target of acute stroke therapy, and is the theoretical basis behind the reperfusion concept. In experimental focal ischemia, early reperfusion has been reported to both prevent infarct growth and aggravate edema formation and hemorrhage, depending on the severity and duration of prior ischemia and the efficiency of reperfusion, whereas neuronal damage with or without enlarged infarction also may result from reperfusion (so-called reperfusion injury). Activated neutrophils contribute to vascular reperfusion damage, yet posthypoxic cellular injury occurs in the absence of inflammatory species. Protein synthesis inhibition occurs in neurons during reperfusion after ischemia, underlying the role that these pathways play in prosurvival and proapoptotic processes that may be differentially expressed in vulnerable and resistant regions of the reperfused brain tissue. Ischemia-induced decreases in the mitochondrial capacity for respiratory activity probably contribute to the ongoing impairment of energy metabolism during reperfusion and possibly also the magnitude of changes seen during ischemia. From these experimental data, the concept of single-drug intervention cannot be effective. Further experimental research is needed, especially of the study of biochemical markers of the injury process to establish the role of several drugs.
Loss of cell polarity causes severe brain dysplasia in Lgl1 knockout mice
Authors: Klezovitch Olga , Fernandez Tania E. , Tapscott Stephen J. , Vasioukhin Valeri
Published: March 2004

Disruption of cell polarity is seen in many cancers; however, it is generally considered a late event in tumor progression. Lethal giant larvae (Lgl) has been implicated in maintenance of cell polarity in Drosophila and cultured mammalian cells. We now show that loss of Lgl1 in mice results in formation of neuroepithelial rosette-like structures, similar to the neuroblastic rosettes in human primitive neuroectodermal tumors. The newborn Lgl1–/– pups develop severe hydrocephalus and die neonatally. A large proportion of Lgl1–/– neural progenitor cells fail to exit the cell cycle and differentiate, and, instead, continue to proliferate and die by apoptosis. Dividing Lgl1–/– cells are unable to asymmetrically localize the Notch inhibitor Numb, and the resulting failure of asymmetric cell divisions may be responsible for the hyperproliferation and the lack of differentiation. These results reveal a critical role for mammalian Lgl1 in regulating of proliferation, differentiation, and tissue organization and demonstrate a potential causative role of disruption of cell polarity in neoplastic transformation of neuroepithelial cells.
Clinical research informationist
Authors: Detlefsen Ellen G.
Published: March 2004

The article describes an informationist who serves a large clinical research team in a medical school as a part‐time information officer. The multidisciplinary team is focused on clinical and research issues in depression as it affects the elderly. The goals, projects, and key findings of the team are highlighted. The emerging role of the information officer is described.
Clinical medical librarian to clinical informationist
Authors: Brown Helen‐Ann
Published: March 2004

Clinical medical librarians stepped out of the library and joined the patient care team in the early 1970s, beginning in Kansas City, Missouri and then Hartford, Connecticut. Now they are present to report the literature, take literature search requests and, most importantly, perceive information needs at Morning Report, bedside rounds, or weekly conferences. Within 24 hours or less, they return to the patient care team with literature to aid in patient planning. Clinical medical librarians also teach online searching in an evidence‐based way and help patient care team members with other research needs. In 2000, the concept of the informationist was introduced. It can begin with clinical medical librarianship and expand to this information specialist in context, being based and salaried in a clinical setting, having information‐seeking skills, knowledge of informatics and the clinical subject area. Both the clinical medical librarian and the clinical informationist contribute to better patient care, medical education and clinical research.
Enabling real estate service chain management through personalised Web interfacing using QFD
Authors: Hamilton John , Selen Willem
Published: March 2004

This paper takes the concept of integrated services to meet individual user needs one step further, by addressing how integrated services can be delivered over the Web in a service chain involving multiple partners. Moreover, a framework is developed and applied to enable fulfilment of individual user needs by developing the appropriate service delivery in terms of Web interface and content, as well as the underlying processes and functionalities, which in turn are defined within an information technology/information systems architecture. The methodology of quality function deployment is used in this context, and applied to a real estate service environment in Australia.
Maintainability of wet areas of non‐residential buildings
Authors: Chew M.Y.L. , De Silva Nayanthara , Tan S.S.
Published: March 2004

This paper discusses some important findings from a research project on the maintainability of wet areas of high‐rise non‐residential, buildings. The implications of six key factors of maintainability namely water‐tightness, spatial, integrity, ventilation, material and plumbing on the occurrence of 14 most common defects found in wet areas were evaluated. Problem areas evaluated include water leakage from ceiling, staining/discolouration, paint defects, cracking/spalling of concrete, cracking/debonding of tiles, fungi/algae growth, pipe leakage and corrosion. An industry wide survey was conducted and the factors including workmanship, design detailing, maintenance and material incompatibility under tropical conditions are identified and discussed.
Outsourcing and quality performance: Malaysia’s public works department
Authors: Abdul‐Aziz Abdul‐Rashid , Ali Normah
Published: March 2004

A brief quality assessment exercise conducted among officers of Malaysia's Public Works Department (PWD) on outsourced quantity surveying services affirmed the view that the consultants' performance was generally unsatisfactory. The performance dimensions cover from preliminary estimates and cost plans to final accounts. The result of this purely academic exercise generated sufficient interest among top decision‐makers at PWD's Contract and Quantity Surveying Division to render quality improvement initiatives feasible. For a large public sector organisation usually afflicted with inertia, the changes that have taken place within such a short space of time are encouraging. What this case study points to is that given sufficient motivation, even a simple quality assessment exercise is able to prompt quality changes.