Showing papers by "University of Glasgow published in 1997"

ORTEP-3 for Windows - a version of ORTEP-III with a Graphical User Interface (GUI)

Abstract: Computer Program Abstracts The category Computer Program Abstracts provides a rapid means of communicating up-to-date information concerning both new programs or systems and significant updates to existing ones. Following normal submission, a Computer Program Abstract will be reviewed by one or two members of the IUCr Commission on Crystallographic Computing. It should not exceed 500 words in length and should follow the standard format given on page 189 of the June 1985 issue of the Journal [J. Appl. CrysL (1985). 18, 189190] and on the World Wide Web at http://www.iucr. ac. uk/journals/jac/software/. Lists of software presented and~or reviewed in the Journal of Applied Crystallography are available on the World Wide Web at the above address, together with information about the availability of the software where this is known. J. App/. CrysL (1997). 30, 565 ORTEP-3 for Windows a version of ORTEP-III with a Graphical User Interface (GUI)

Aid, Policies, and Growth

Abstract: Aid has a positive impact on growth in developing countries with good fiscal, monetary, and trade policies. Aid appears not to affect policies systematically either for good or for ill. Any tendency for aid to reward good policies has been overwhelmed by donorse pursuit of their own strategic interests. Burnside and Dollar use a new database on foreign aid to examine the relationships among foreign aid, economic policies, and growth of per capita GDP. In panel growth regressions for 56 developing countries and six four-year periods (1970-93), they find that the policies that have a great effect on growth are those related to fiscal surplus, inflation, and trade openness. They construct an index for those three policies and have that index interact with foreign aid. They have instruments for both aid and aid interacting with policies. They find that aid has a positive impact on growth in developing countries with good fiscal, monetary, and trade policies. In the presence of poor policies, aid has no positive effect on growth. This result is robust in a variety of specifications, which include or exclude middle-income countries, include or exclude outliers, and treat policies as exogenous or endogenous. They examine the determinants of policy and find no evidence that aid has systematically affected policies, either for good or for ill. They estimate an aid allocation equation and show that any tendency for aid to reward good policies has been overwhelmed by donors' pursuit of their own strategic interests. In a counterfactual, they reallocate aid, reducing the role of donor interests and increasing the importance of policy. Such a reallocation would have a large positive effect on developing countries' growth rates. This paper - a product of the Macroeconomics and Growth Division, Policy Research Department - is part of a larger effort in the department to study the effectiveness of foreign aid. The study was funded by the Bank's Research Support Budget under research project Economic Policies and the Effectiveness of Foreign Aid (RPO 681-70).

Nomenclature of amphiboles; report of the subcommittee on amphiboles of the International Mineralogical Association, Commission on New Minerals and Mineral Names

Abstract: The International Mineralogical Association's approved amphibole nomenclature has been revised to simplify it, make it more consistent with divisions generally at 50%, define prefixes and modifiers more precisely, and include new amphibole species discovered and named since 1978, when the previous scheme was approved. The same reference axes form the basis of the new scheme and most names are little changed, but compound species names like tremolitic hornblende (now magnesiohornblende) are abolished, as are crossite (now glaucophane or ferroglaucophane or magnesioriebeckite or riebeckite), tirodite (now manganocummingtonite), and dannemorite (now manganogrunerite). The 50% rule has been broken only to retain tremolite and actinolite as in the 1978 scheme; the sodic-calcic amphibole range has therefore been expanded. Alkali amphiboles are now sodic amphiboles. The use of hyphens is defined. New amphibole names approved since 1978 include nyboite, leakeite, kornite, ungarettiite, sadanagaite, and cannilloite. All abandoned names are listed. The formulae and source of the amphibole end-member names are listed and procedures outlined to calculate Fe (super 3+) and Fe (super 2+) where not determined by analysis.

The physics of low-dimensional semiconductors : an introduction

Abstract: Preface Introduction 1. Foundations 2. Electrons and phonons in crystals 3. Heterostructures 4. Quantum wells and low-dimensional systems 5. Tunnelling transport 6. Electric and magnetic fields 7. Approximate methods 8. Scattering rates: the Golden Rule 9. The two-dimensional electron gas 10. Optical properties of quantum wells Appendix 1. Table of physical constants Appendix 2. Properties of important semiconductors Appendix 3. Properties of GaAs-AlAs alloys at room temperature Appendix 4. Hermite's equation: harmonic oscillator Appendix 5. Airy functions: triangular well Appendix 6. Kramers-Kronig relations and response functions Bibliography.

Microcytic anaemia mice have a mutation in Nramp2, a candidate iron transporter gene.

Abstract: Although disorders of iron metabolism are prevalent, iron transport remains poorly understood. To address this problem, we undertook a positional cloning strategy to identify the causative mutation in mice with microcytic anaemia (mk). Homozygous mk/mk mice have microcytic, hypochromic anaemia due to severe defects in intestinal iron absorption and erythroid iron utilization1–4. We report the identification of a strong candidate gene for mk, and suggest that the phenotype is a consequence of a missense mutation in Nramp2 (ref. 5), a previously identified gene of unknown function. Nramp2 is homologous to Nrampl, a gene active in host defense. If Nramp2 is mk, as the cumulative evidence suggests, our findings have broad implications for the understanding of iron transport and resistance to intracellular pathogens.

The emergence of life from iron monosulphide bubbles at a submarine hydrothermal redox and pH front

Abstract: Here we argue that life emerged on Earth from a redox and pH front at c. 4.2 Ga. This front occurred where hot (c. 150°C), extremely reduced, alkaline, bisulphide-bearing, submarine seepage waters interfaced with the acid, warm (c. 90°C), iron-bearing Hadean ocean. The low pH of the ocean was imparted by the ten bars of CO 2 considered to dominate the Hadean atmosphere/hydrosphere. Disequilibrium between the two solutions was maintained by the spontaneous precipitation of a colloidal FeS membrane. Iron monosulphide bubbles comprising this membrane were inflated by the hydrothermal solution upon sulphide mounds at the seepage sites. Our hypothesis is that the FeS membrane, laced with nickel, acted as a semipermeable catalytic boundary between the two fluids, encouraging synthesis of organic anions by hydrogenation and carboxylation of hydrothermal organic primers. The ocean provided carbonate, phosphate, iron, nickel and protons; the hydrothermal solution was the source of ammonia, acetate, HS − , H 2 and tungsten, as well as minor concentrations of organic sulphides and perhaps cyanide and acetaldehyde. The mean redox potential (ΔEh) across the membrane, with the energy to drive synthesis, would have approximated to 300 millivolts. The generation of organic anions would have led to an increase in osmotic pressure within the FeS bubbles. Thus osmotic pressure could take over from hydraulic pressure as the driving force for distension, budding and reproduction of the bubbles. Condensation of the organic molecules to polymers, particularly organic sulphides, was driven by pyrophosphate hydrolysis. Regeneration of pyrophosphate from the monophosphate in the membrane was facilitated by protons contributed from the Hadean ocean. This was the first use by a metabolizing system of protonmotive force (driven by natural ApH) which also would have amounted to c. 300 millivolts. Protonmotive force is the universal energy transduction mechanism of life. Taken together with the redox potential across the membrane, the total electrochemical and chemical energy available for protometabolism amounted to a continuous supply at more than half a volt. The role of the iron sulphide membrane in keeping the two solutions separated was appropriated by the newly synthesized organic sulphide polymers. This organic take-over of the membrane material led to the miniaturization of the metabolizing system. Information systems to govern replication could have developed penecontemporaneously in this same milieu. But iron, sulphur and phosphate, inorganic components of earliest life, continued to be involved in metabolism.

Quantitative Analysis of the Flavonoid Content of Commercial Tomatoes, Onions, Lettuce, and Celery

Abstract: Quantitative estimates of conjugated flavonoid content were obtained by using HPLC to analyze the level of free flavonoids present in acid-hydrolyzed extracts from commercial fruits and vegetables. Cherry tomatoes contained 17−203 μg of quercetin g-1 fresh weight compared to 2.2−11 μg g-1 detected in normal-sized Scottish, Spanish, and Dutch beef tomatoes. The quercetin levels in onions ranged from 185 to 634 μg of quercetin g-1 fresh weight. “Round” lettuce contained 11 μg of quercetin g-1 fresh weight compared to 911 μg g-1 in the outer leaves and 450 mg g-1 in the inner leaves of “Lollo Rosso” lettuce. The conjugated flavonoid content of celery was very variable, ranging from undetectable to 40 μg of luteolin and 191 μg of apigenin g-1 fresh weight. Cooking lowered the quercetin content of both tomatoes and onions with greater reductions being detected following microwaving and boiling than after frying. Keywords: HPLC; quantitative analysis; flavonoids; tomatoes; onions; lettuce; celery; diet

Influenza Vaccination of Health Care Workers in Long-Term-Care Hospitals Reduces the Mortality of Elderly Patients

Abstract: Vaccination of health care workers (HCWs) is recommended as a strategy for preventing influenza in elderly patients in long-term care. However, there have been no controlled studies to show whether this approach is effective. During the winter of 1994-1995, 1059 patients in 12 geriatric medical long-term-care sites, randomized for vaccination of HCWs, were studied. In hospitals where HCWs were offered vaccination, 653 (61%) of 1078 were vaccinated. Vaccination of HCWs was associated with reductions in total patient mortality from 17% to 10% (odds ratio [OR], 0.56; 95% confidence interval [CI], 0.40-0.80) and in influenza-like illness (OR, 0.57; 95% CI, 0.34-0.94). Vaccination of patients was not associated with significant effects on mortality (OR, 1.15; 95% CI, 0.81-1.64). Results of this study support recommendations for vaccination against influenza of HCWs in long-term geriatric care. Vaccination of frail elderly long-term-care patients may not give clinically worthwhile benefits.

A mechanistic analysis of nondisruptive axonal injury: a review

Abstract: Axons are particularly at risk in human diffuse head injury. Use of immunocytochemical labeling techniques has recently demonstrated that axonal injury (AI) and the ensuing reactive axonal change is, probably, more widespread and occurs over a longer posttraumatic time in the injured brain than had previously been appreciated. But the characterization of morphologic or reactive changes occurring after nondisruptive AI has largely been defined from animal models. The comparability of AI in animal models to human diffuse AI (DAI) is discussed and the conclusion drawn that, although animal models allow the analysis of morphologic changes, the spatial distribution within the brain and the time course of reactive axonal change differs to some extent both between species and with the mode of brain injury. Thus, the majority of animal models do not reproduce exactly the extent and time course of AI that occurs in human DAI. Nonetheless, these studies provide good insight into reactive axonal change. In ...

Guidelines for the design and conduct of clinical trials on dentine hypersensitivity

Abstract: Clinical trials on dentine hypersensitivity have been numerous and protocols varied. To date there is little consensus as to the conduct of studies on this poorly-understood yet common and painful dental condition. A committee of interested persons from academia and industry was convened to discuss the subject of clinical trials on dentine hypersensitivity and a consensus report is presented. A double-blind randomized parallel groups design is recommended, although cross-over designs may be used for the preliminary screening of agents. Subjects may have multiple sites scored. Sample size will be determined by estimating the variability in the study population, the effect to be detected and the power of the statistical test to be used. Subject selection is based on a clinical diagnosis of dentine hypersensitivity, excluding those with conflicting characteristics such as currently-active medical or dental therapy. The vestibular surfaces of incisors, cuspids and bicuspids are preferred as sites to be tested. A range of sensitivity levels should be included. Tactile, cold and evaporative air stimuli should be applied. Negative and benchmark controls should be incorporated. Most trials should last 8 weeks. Sensitivity may be assessed either in terms of the stimulus intensity required to evoke pain or the subjective evaluation of pain produced by a stimulus using a visual analog or other appropriate scale. The subject's overall assessment may be determined by questionnaire. Outcomes should be expressed in terms of clinically significant changes in symptoms. Follow-up evaluation is required to determine the persistence of changes. At least 2 independent trials should be conducted before a product receives approval.

Flexible AC transmission systems (FACTS)

Abstract: The paper reviews literature which addresses the application of Flexible AC Transmission System (FACTS) concepts to the improvement of Power System utilisation and performance. It summarises literature on using high speed thyristor based control of HVAC power system elements to enhance the power carrying capacity of existing transmission circuits without compromising reliability. It describes a study system representative of existing power systems that has been developed to evaluate the economic and technical issues of loading transmission lines to their thermal limits. Considered are two scenarios, a multi-line corridor and a long radial interconnection, where the issues addressed are transient and dynamic stability, power flow control, reactive support and voltage stability. A benchmark system is developed to validate performance of die more simple devices. It is concluded that FACTS devices have the potential to significantly increase system stability margins thereby increasing loading capabil...

Interleukin-15 mediates T cell-dependent regulation of tumor necrosis factor-alpha production in rheumatoid arthritis

Abstract: Tumor necrosis factor-alpha occupies a central role in rheumatoid arthritis (RA) pathogenesis. We now report that interleukin-15 (IL-15) can induce TNF-alpha production in RA through activation of synovial T cells. Peripheral blood (PB) T cells activated by IL-15 induced significant TNF-alpha production by macrophages via a cell-contact-dependent mechanism. Freshly isolated RA synovial T cells possessed similar capability, and in vitro, IL-15 was necessary to maintain this activity. IL-15 also induced direct TNF-alpha production by synovial T cells. In contrast, IL-2 induced significantly lower TNF-alpha production in either cell-contact-dependent or direct culture, and IL-8 and MIP-1 alpha were ineffective. Antibodies against CD69, LFA-1 or ICAM-1 significantly inhibited the ability of T cells to activate macrophages by cell contact.

Epstein‐Barr virus‐associated Hodgkin's disease: Epidemiologic characteristics in international data

Abstract: Hodgkin's disease (HD) has long been suspected to have an infectious precursor, and indirect evidence has implicated Epstein-Barr virus (EBV), a ubiquitous herpesvirus, as a causal agent. Recent molecular studies using EBER in situ hybridization or latency membrane protein-I (LMP-I) immunohistochemistry have identified EBV latent infection in up to 50% of HD tumors. However, the epidemiologic features of these cases have not been examined in detail. To explore the epidemiology of EBV-positive HD so as to understand the role of EBV in HD etiology more clearly, this project accumulated patient data from 14 studies that had applied these EBV assays to HD tumors. With information on age at diagnosis, sex, ethnicity, histologic subtype, country of residence, clinical stage and EBV tumor status from 1,546 HD patients, we examined risk for EBV-positive disease using logistic regression. Forty percent of subjects had EBV-positive tumors, and EBV prevalence varied significantly across groups defined by the study variables. Odds ratios (OR) for EBV-associated HD were significantly elevated for Hispanics vs. whites (OR = 4.1), mixed cellularity vs. nodular sclerosis histologic subtypes (OR = 7.3, 13.4, 4.9 for ages 0-14, 15-49, 50+ years), children from economically less-developed vs. more-developed regions and young adult males vs. females (OR = 2.5). These findings suggest that age, sex, ethnicity and the physiologic effects of poverty may represent biologic modifiers of the EBV association and confirm that this association is strongly but variably linked to histologic subtype. The data augment biologic evidence that EBV is actively involved in HD pathogenesis in some cases but describe epidemiologic complexity in this process.

The anatomical basis of intestinal immunity.

Abstract: The lymphoid tissues associated with the intestine are exposed continuously to antigen and are the largest part of the immune system. Many lymphocytes are found in organised tissues such as the Peyer's patches and mesenteric lymph nodes, as well as scattered throughout the lamina propria and epithelium of the mucosa itself. These lymphocyte populations have several unusual characteristics and the intestinal immune system is functionally and anatomically distinct from other, peripheral compartments of the immune system. This review explores the anatomical and molecular basis of these differences, with particular emphasis on the factors which determine how the intestinal lymphoid tissues discriminate between harmful pathogens and antigens which are beneficial, such as food proteins or commensal bacteria. These latter antigens normally provoke immunological tolerance, and inappropriate responses to them are responsible for immunopathologies such as food hypersensitivity and inflammatory bowel disease. We describe how interactions between local immune cells, epithelial tissues and antigen-presenting cells may be critical for the induction of tolerance and the expression of active mucosal immunity. In addition, the possibility that the intestine may act as an extrathymic site for T-cell differentiation is discussed. Finally, we propose that, under physiological conditions, immune responses to food antigens and commensal bacteria are prevented by common regulatory mechanisms, in which transforming growth factor beta plays a critical role.

Why don't birds lay more eggs?

Abstract: Fifty years ago David Lack put forward a key hypothesis in life-history theory: that avian clutch is ultimately determined by the number of young that parents can provide with food. Since then, a plethora of brood manipulations has shown that birds can rear more young than the number of eggs they lay, and prompted a search for negative effects of increased effort on future reproduction. However, recent studies have shown that the demands of laying and incubating eggs generally omitted from experiments, could affect parental fitness. Lack's hypothesis, and the tests of its validity, need to be extended to encompass the full demands of producing and rearing the brood.

Pizza into Java: translating theory into practice

Abstract: Pizza is a strict superset of Java that incorporates three ideas from the academic community: parametric polymorphism, higher-order functions, and algebraic data types. Pizza is defined by translation into Java and compiles into the Java Virtual Machine, requirements which strongly constrain the design space. Nonetheless, Pizza fits smoothly to Java, with only a few rough edges.

Origin of the Anomalous Magnetic Behavior in Single Crystal Fe 3 O 4 Films

Abstract: Antiphase boundaries (APBs) were observed in ${\mathrm{Fe}}_{3}{\mathrm{O}}_{4}$ single crystal films grown on MgO. The APBs are an intrinsic consequence of the nucleation and growth mechanism in films. Across an APB, the intrasublattice superexchange coupling is greatly strengthened, while the intersublattice superexchange coupling is weakened, reversing the dominant interaction from that found in the bulk. Thus the APB separates oppositely magnetized regions, consistent with Lorentz microscopy measurements. The APBs induce very large saturation fields and nearly random magnetization distribution in zero field.

The reliability of a dialogue structure coding scheme

Abstract: This paper describes the reliability of a dialogue structure coding scheme based on utterance function, game structure, and higher-level transaction structure that has been applied to a corpus of spontaneous task-oriented spoken dialogues.

The clinical significance of surface antigen variants of hepatitis B virus

Abstract: Hepatitis B surface antigen (HBsAg) is not only critical to the biology of hepatitis B virus (HBV), it is also the basis of the currently available vaccines, assays to detect it in serum are crucial for diagnosis of infection and antibodies against it are used clinically to suppress infection of transplanted livers. All of these rely on antigenic interactions between HBsAg and HBsAb. Thus, it should not be surprise that changes in epitopes will affect all these situations. It is useful to classify such changes simplistically as variants, found in natural isolates, and mutants, which are observed to emerge, usually under immunological pressure, often medical in origin. The former tend to affect the sensitivity of diagnostic assays and the latter allow escape of viruses in vaccinees and those being treated with HBsAb. The majority of these changes cluster in the hydrophilic central core of HBsAg, from aa99 up to 169. They are gaining importance as causes of mistaken diagnosis and are associated with infection of vaccinees and transplanted livers. There is a danger that they will become the dominant strains as vaccination becomes universal. More data are required on the epidemiology and antigenicity of these changes.

The rat anococcygeus muscle and its response to nerve stimulation and to some drugs

Abstract: 1. A new smooth muscle preparation, the rat anococcygeus muscle, is described. The muscle is paired, thin, consists of smooth muscle only and the muscle cells are organized in parallel bundles. It has a dense adrenergic innervation distributed throughout the muscle but apparently no cholinergic innervation. The muscles are easily isolated.2. The muscle contracts to noradrenaline, acetylcholine, furmethide, 5-hydroxytryptamine, but not to histamine. Isoprenaline produces contraction at high concentrations. The effects of noradrenaline and acetylcholine are blocked by phentolamine and atropine respectively. The response to isoprenaline is little affected by propranolol.3. The muscle contracts in response to field stimulation or stimulation of extrinsic nerves. This response is completely blocked by phentolamine but unaffected by hexamethonium or atropine.4. Guanethidine 10(-6)-5 x 10(-6)M blocks the motor response to nerve stimulation and potentiates that to noradrenaline. Higher concentrations of guanethidine raise tone. In the presence of raised tone, field stimulation produces an inhibitory response insensitive to hexamethonium but abolished by tetrodotoxin 2 x 10(-7) g/ml. This inhibitory response to stimulation can also be shown after other drugs which raise tone.5. The inhibitory response to nerve stimulation is not mimicked by acetylcholine, isoprenaline or ATP, nor blocked by atropine, phentolamine, phenoxybenzamine, propranolol, hexamethonium or lysergic acid diethylamide.

Growth compensation in juvenile atlantic salmon: responses to depressed temperature and food availability

Abstract: This study examines behavioral and physiological responses of juvenile At- lantic salmon (Salmo salar) adopting alternative life history patterns following a period of reduced growth. We manipulated the growth rates of premigratory and nonmigratory salmon by either reducing food availability or maintaining water at low temperature (4-60C). A third group of fish was kept at ambient temperatures (12-14'C) and fed ad libitum to provide a control. Fish in both experimental groups exhibited compensatory growth after the manipulation period, even though the manipulations had slowed growth rather than caused mass loss. The timing and duration of compensatory growth were affected by the nature of the constraint and the developmental pathway adopted. Compensatory responses were more persistent and stronger among premigratory fish than among nonmigratory. Fish kept at low temperature did not accelerate growth immediately after transfer to ambient temperatures, but they subsequently grew faster than controls for up to 215 d after the end of the manipulation period. This mitigated the effects of the period of low temperatures, although by the end of the experiment they were still smaller than the controls. Fish on reduced rations showed no such time lag, and they grew significantly faster than controls immediately upon regaining access to full rations. These fish attained the same body size as controls by the end of the experiment (day 215). The manipulations caused fish to reduce their growth in mass more than their rate of skeletal growth, but all fish achieved "normal" mass for their length (as compared to controls) within a week of transfer to full feeding or ambient temperature. The main mechanism underlying compensatory growth rates was apparently the increase of intake rates, although this was insufficient to explain the strong compensation shown by temperature-manipulated fish in the presence of larger (and thus competitively superior) individuals. Instead these fish enhanced their growth rate by ap- parently increasing the duration of the daily feeding period, and avoiding aggressive in- teractions. We interpret the observed compensation for periods of slowed growth as indi- cating that growth rate is normally submaximal and can be increased if the animal has fallen below its expected trajectory; thus premigratory fish may have shown a greater compensation because survival rates during migration are strongly size-dependent.

The H1 detector at HERA

Abstract: General aspects of the H1 detector at the electron-proton storage ring HERA as well as technical descriptions of the magnet, luminosity system, trigger, slow-control, data acquisition and off-line data handling are given. The three major components of the detector, the tracking, calorimeter and muon detectors, will be described in a forthcoming article. The present paper describes the detector that was used from 1992 to the end of 1994. After this a major upgrade of some components was undertaken. Some performance figures from luminosity runs at HERA during 1993 and 1994 are given.