Search Results - (Author, Cooperation:S. J. Smith)

2011-02-26

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Calcium/analysis ; Carbon/analysis ; Carbon Dioxide/analysis ; *Climate ; Droughts/*history/statistics & numerical data ; Fossils ; Fresh Water ; Geologic Sediments/analysis/chemistry ; Global Warming/statistics & numerical data ; History, Ancient ; Human Activities ; New Mexico ; Plant Development ; Plants/metabolism ; Pollen/chemistry ; Rain ; Seasons ; Soil Microbiology ; Temperature ; Time Factors

2013-11-26

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Animals ; Astrocytes/cytology/*metabolism ; Brain/cytology ; In Vitro Techniques ; Lateral Thalamic Nuclei/cytology/metabolism ; Learning/physiology ; Membrane Proteins/deficiency/genetics/*metabolism ; Mice ; Mice, Transgenic ; Neural Pathways/cytology/*metabolism ; *Phagocytosis ; Proto-Oncogene Proteins/deficiency/genetics/*metabolism ; Receptor Protein-Tyrosine Kinases/deficiency/genetics/*metabolism ; Retina/physiology ; Synapses/*metabolism

2012-06-23

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Animals ; Astrocytes/cytology/*metabolism/secretion ; Cerebellum/cytology/metabolism ; Culture Media, Conditioned/metabolism/pharmacology ; Excitatory Postsynaptic Potentials/*physiology ; Female ; Glypicans/deficiency/*metabolism/pharmacology ; Hippocampus/cytology/metabolism ; Humans ; Male ; Mice ; Mice, Inbred C57BL ; Rats ; Rats, Sprague-Dawley ; Receptors, AMPA/*metabolism ; Retinal Ganglion Cells/cytology/drug effects/metabolism ; Synapses/drug effects/*metabolism/pathology

2018-05-10

American Physical Society (APS)

1098-0121

1095-3795

Physics

Superfluidity and superconductivity

2018-04-12

BMJ Publishing

2044-6055

Medicine

Open access, Ear, nose and throat/otolaryngology

2012-09-21

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Animals ; Appetitive Behavior/drug effects/*physiology ; Avoidance Learning/drug effects/*physiology ; Corticotropin-Releasing Hormone/*metabolism/pharmacology ; Dopamine/metabolism/secretion ; Male ; Mice ; Mice, Inbred C57BL ; Nucleus Accumbens/*metabolism/physiopathology ; Receptors, Corticotropin-Releasing Hormone/agonists/antagonists & ; inhibitors/deficiency/metabolism ; Signal Transduction/drug effects ; Stress, Psychological/*metabolism/physiopathology

2018-06-14

The American Society for Microbiology (ASM)

0022-538X

1098-5514

Medicine

1467-8640

Blackwell Publishing Journal Backfiles 1879-2005

Computer Science

Although game-tree search works well in perfect-information games, it is less suitable for imperfect-information games such as contract bridge. The lack of knowledge about the opponents’ possible moves gives the game tree a very large branching factor, making it impossible to search a significant portion of this tree in a reasonable amount of time.This paper describes our approach for overcoming this problem. We represent information about bridge in a task network extended to represent multi-agency and uncertainty. Our game-playing procedure uses this task network to generate game trees in which the set of alternative choices is determined not by the set of possible actions, but by the set of available tactical and strategic schemes.We have tested this approach on declarer play in the game of bridge, in an implementation called Tignum 2. On 5000 randomly generated notrump deals, Tignum 2 beat the strongest commercially available program by 1394 to 1302, with 2304 ties. These results are statistically significant at the α= 0.05 level. Tignum 2 searched an average of only 8745.6 moves per deal in an average time of only 27.5 seconds per deal on a Sun SPARCstation 10. Further enhancements to Tignum 2 are currently underway.

Electronic Resource

1089-7623

AIP Digital Archive

Physics

Electrical Engineering, Measurement and Control Technology

We discuss the nature of errors which may occur when the spectra of random signals not obeying Gaussian statistics are measured with typical rf spectrum analyzers. These errors depend on both the noise statistics and the process used to detect the random signal after it has been passed through a narrow bandpass filter within the spectrum analyzer. In general, for random signals not obeying Gaussian statistics, the output of the bandpass filter must be measured with a square law detector if the resulting measurement is to be strictly proportional to the power spectrum of the input signal. We compare measurements of the power spectra of non-Gaussian noise using a commerical spectrum analyzer with its resident envelope detector, with measurements by the same analyzer fitted with a square law detector. Differences of about 5% were observed.

Electronic Resource

1365-2044

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Six hundred and ninety–four members of the Intensive Care Society working in the UK were surveyed by postal questionnaire between May and November 1993 to determine their management of convulsive status epilepticus resistant to initial therapy with intravenous diazepam and phenytoin. Four hundred and eight forms were completed and returned (58.8%). The survey revealed that, following failure of initial management, a benzodiazepine infusion (35%) or anaesthetic induction agent (32%) were the preferred second lines of treatment in intensive care units. In paediatric intensive care units, phenobarbitone (31 %) was the agent of choice. Most respondents (57%) gave anaesthetic induction agents within 60min of the start of status epilepticus, the majority choosing thiopentone (82%). Patients were usually monitored using clinical assessment only (45%), except in paediatric intensive care units and specialist neurological or neurosurgical units where the majority used a cerebral function monitor. Only 12%〉 of the respondents were aware of a protocol for status epilepticus in their intensive care units. The most frequently used therapeutic and monitoring strategies in the management of refractory status epilepticus in the UK are insufficient and need re–evaluation.

Electronic Resource

1365-2109

Blackwell Publishing Journal Backfiles 1879-2005

Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Abstract. Production of Florida red tilapia seed (eggs, sacfry and fry) in 34-m2 above-ground tanks using recirculated brackishwater (12 ppt) was studied over a 5-month period on Lee Stocking Island (Exuma Cays, Bahamas). Four tanks were stocked with year class 1 (YCI) breeders, while 2 tanks were stocked with year class 2 (YCII) breeders at densities of 200 and 240/tank (5·9 and 7·1/m2), respectively, and at a sex ratio of 3 females to 1 male, beginning in November 1988. Seed production was measured by removing free-swimming fry from tanks and eggs and sacfry from the mouths of brooding females, and assessing the number of each at 15 to 16-day intervals from February to June 1989. Average seed production (seed/m2/day) was significantly higher in YCI (52·3) than in YCII (36·0) broodstock, indicating the advantages of replacing broodstock with yearling breeders each year.

Electronic Resource

1365-2222

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

In this study we have examined the relationship between the in vitro basophil histamine-releasing activity of human IgG anti-IgE, isolated as euglobulin fractions from sera of asthmatic patients, and its IgG1/IgG4 subclass distribution. In particular, we have investigated whether IgG anti-IgE modulates allergen-induced basophil activation. The study has revealed that only a small proportion of IgG anti-IgE samples triggered histamine release from basophils of an asthmatic individual (4/21; 19%), a hay fever sufferer (4/10; 40%) and a healthy person (7/21; 33%). The basophil histamine-releasing activity of IgG anti-IgE did not seem to be determined by the IgG1/IgG4 subclass composition of the IgG anti-IgE preparation used. Furthermore, we have demonstrated that autoanti-IgE antibodies modulate allergen-induced basophil histamine release. The three modulatory effects exerted by IgG anti-IgE antibodies on allergen-triggered basophil activation (i.e. additive, synergistic and blocking) were not dependent on the subclass nature of IgG anti-IgE or the use of histamine-releasing anti-IgE preparations. Our data suggest that IgG anti-IgE antibodies in asthma patients may consist of two functionally distinct subpopulations: those which up-regulate (pro-allergic) and those which down-regulate (anti-allergic) the allergic release of mediators from mast cells and basophils.

Electronic Resource

1365-2222

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Background Mast cells are responsible for eliciting the early phase and for contributing to the development of the late phase of allergic reactions, through the release of cytokines and other inflammatory mediators.Objective To assess whether the glucocorticoid dexamethasone has a direct effect on mast cell progenitor maturation and on mature cord blood-derived mast cell properties.Methods Mast cells were obtained by culturing human umbilical cord blood mononuclear cells with stem cell factor, IL-6 and prostaglandin E2. Mast cell numbers were assessed by Toluidine Blue staining and immunocytochemistry of tryptase positive cells. The expression of FcεRI, CD49d and c-kit was assessed by flow cytometry. Histamine release was determined by a radioenzymatic assay. Cys-LT, GM-CSF and TNF-α production and release were determined by ELISA.Results Dexamethasone (10−6 M−10−9 M) time- and dose-dependently inhibited the maturation of the mast cell progenitors. Dexamethasone did not affect the basal expression of FcεRI, CD49d and c-kit, but it inhibited the IgE-dependent enhanced expression of FcεRI. Dexamethasone (10−6 M−10−9 M) had no significant effect on FcεRI-dependent histamine release or the synthesis and release of Cys-LT from the mature mast cells. However, pre-incubation of the mast cell cultures with dexamethasone for 1 h, prior to cross-linking of FcεRI, dose-dependently inhibited the production and secretion of both GM-CSF and TNF-α.Conclusions From these in vitro data we propose that glucocorticosteroids are effective drugs in the management of allergic inflammation due to their capacity to inhibit mast cell development, IgE-dependent FcεRI expression and mast cell production of GM-CSF and TNF-α.

Electronic Resource

1365-2109

Blackwell Publishing Journal Backfiles 1879-2005

Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Five diets were formulated to investigate the effects of substituting wheat flour and soybean meal with various inclusion levels of seaweed (Gracilaria sp.) meal on the diet stability, performance and carcass composition of juvenile shrimp Penaeus monodon Fabricius. Gracilaria meal inclusion levels from 5% to 30% were tested against a control (0% seaweed) in isonitrogenous, isoenergetic diets fed for 60 days to quadruplicate groups of shrimp held in laboratory brackishwater recirculation system.Diets containing Gracilaria meal at up to 10% inclusion had no significant effects on diet water stability (after 12 h), shrimp performance or carcass composition compared with the control diet lacking seaweed. Diets containing 0-15%Gracilaria meal remained 〉88% water stable after 12 h, shrimp specific growth rates (SGRs) were 7.9-8.0% wet body weight day-1. survival was 48-56%, food conversion ratios were 3.1-3.5, and final carcass lipid levels were 6.8-7.5%. The 30% inclusion levels of Gracilaria meal resulted in a significant deterioration in diet water stability (86% after 12 h), shrimp growth (SGR 7.3% wet body weight day-1) and carcass lipid level (4.1%). It is suggested that with the low cost and increasing availability of Gracilaria, it may be a suitable ingredient for low-level inclusion into formulated diets for shrimp culture. The possibility of using seaweed meals for this purpose is discussed with regard to diversifying the market for cultured seaweeds and enhancing the integration of seaweed culture into coastal aquaculture systems.

Electronic Resource

1365-2109

Blackwell Publishing Journal Backfiles 1879-2005

Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Intensive marine and brackishwater shrimp farms commonly use large quantities of zeolites in ponds with the aim of removing ammonia through ion exchange, providing physical cover over sediments to prevent leaching of metabolites into the water column, removing suspended solids, and improving water colour and diatom blooms. Zeolites have the capacity to remove ammonia and other nutrients/ metabolites from fresh waters by ion exchange and absorption. However, there are doubts as to their efficacy and cost-effectiveness in saline waters. This research was conducted to investigate the effect of zeolites on water quality under a range of conditions in seven laboratory-based trials and one pond trial. These investigated the effects of six types of commercially available zeolites and three other alumino-silicate clays at levels from one to 26 times the recommended dose rate (380 kg ha-1 month-1) in water at salinities of 0-30%o for periods of 3-19 days. The results indicated that none of the zeolites or natural alumino-silicate clays from Thailand had any significant effects on the removal of nutrients from water at salinities of 0-30%. Neither were these able to prevent nutrient emission from shrimp pond sediments in water at 20-2l%o salinity. Furthermore, none of the other suggested functions of reducing levels of particulate nutrients, enhancing algal biomass, or affecting oxygen and pH dynamics were evident. This study could not establish any useful, cost-effective role for zeolites in shrimp pond culture.

Electronic Resource

1365-2109

Blackwell Publishing Journal Backfiles 1879-2005

Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

The present authors investigated the impact of farming intensity and the prevailing season on water quality in intensive tropical shrimp farms. The weekly water quality samples from the inlets and production ponds of two commercial shrimp farms operating partial water exchange schedules and representing low and high farming intensities in Thailand (with Penaeus monodon Fabricius production rates of 4 and 9 t ha–1 cycle–1, respectively) were analysed over two consecutive production cycles, covering the wet (monsoon) and dry seasons. Significant differences in inlet water quality between farms occurred only in salinity, temperature and suspended solids. The present authors assessed impacts of farming intensity and season on production pond water quality parameters using: (1) an analysis of variance ( anova) of measurements in replicate ponds during the final month of the production cycle; and (2) a trend analysis which classified trends in parameters over the cycle as externally or internally determined. The prevailing season was found to have a strong impact on salinity, temperature, pH, nitrate, dissolved reactive phosphorus, total phosphorus and dissolved oxygen in the final month of the cycle. The trends in these parameters were largely externally determined or absent. Nitrite and chlorophyll a were affected by production intensity in interaction with season and showed mainly internally determined trends. This indicates that nitrogen transformation processes responded to input levels as well as seasonal influences. Ammonia was highly variable and no significant intensity or season effects were detected, but trends were internally determined only at high intensity and more pronounced in the dry rather than the wet season. The results indicate strong seasonal effects on water quality in tropical shrimp ponds, direct in some parameters and indirect in others, including those linked to nitrogen transformations. The mechanisms of seasonal variation and the implications of these changes for water quality management call for further investigation.

Electronic Resource

1365-2036

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Primed continuous infusion and repeated intravenous injections of ranitidine (daily dose 200 mg) were compared in a homogeneous population of postoperative intensive care unit patients in a randomized fashion. Intragastric pH was measured continuously for 72–96 h with combined glass electrodes positioned in the gastric corpus. Patients whose intragastric acidity fell below pH 4.0 for 70% of a 24-h period within 48 h after the operation (baseline period) were considered ‘at risk’ of developing stress-related lesions. From the 26 patients screened, 18 fulfilled this criterion. Nine received the continuous infusion regimen (50 mg bolus+0.125 mg.kg/h) and nine received repeated boluses (50 mg ranitidine every 6 h). A consistent decrease of intragastric acidity was shown in each group by a rise in 24-h median pH from 1.4 (1.3–1.7; 26th–75th percentile) during the baseline period to 4.2 (1.9–5.4, P 〈 0.01) for the continuous infusion and from 1.55 (1.1–2.2) to 2.65 (2.1–3.5, P 〈 0.02) for the repeated boluses during the final 24 h of the therapy period. During that period intragastric pH was maintained above 4 for 52% of time by continuous infusion and for 40% of time for repeated boluses compared with 10.8% (P= 0.01) and 6.2% (P= 0.008) of time, respectively, in the baseline period. In conclusion, although no statistically significant differences between the two regimens could be detected, the continuous infusion regimen tended to show slightly better results in percentages of time that pH values were above 1 to 7, and in median 24–h pH values.

Electronic Resource

1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] THE humble soil nematode Caenorhab-ditis elegans has proved a useful tool for the extension of the study of gene-protein relationships from prokaryotic to eukaryotic organisms (see News and Views 269, 11; 1977). A variety of uncoordinated (une) mutants can be isolated by their behavioural ...

Electronic Resource

1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] MUSCLE contraction involves .the repetitive interaction of crossbridges from thick filaments with thin filaments, impelled by the hydrolysis of ATP. Although calcium is the universal intracellular signal which triggers contraction, there seem to be two targets for its action. In vertebrate skeletal ...

Electronic Resource

1398-9995

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

In this paper, we have determined the levels of IgG1 and IgG4 anti-IgE in the sera of 66 asthma patients suffering from mild (n= 24), moderate (n= 23), or severe (n= 19) symptoms, and 20 nonatopic, healthy subjects. The study has revealed that although asthma patients have significantly elevated levels of IgG1 and IgG4 anti-IgE antibodies, the concentration of these autoantibodies is not related to the severity of asthma. This conclusion may be related to the known heterogeneity of autoanti-IgE antibodies in terms of their ability to trigger basophil histamine release.

Electronic Resource