Search Results - (Author, Cooperation:R. Houghton)

2018-03-14

Wiley-Blackwell

1354-1013

1365-2486

Biology

Energy, Environment Protection, Nuclear Power Engineering

Geography

2018-09-29

Nature Publishing Group (NPG)

2041-1723

Biology

Chemistry and Pharmacology

Natural Sciences in General

Physics

2011-07-19

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Atmosphere ; Biomass ; Carbon/analysis ; Carbon Dioxide/analysis ; *Carbon Sequestration ; Climate Change ; Conservation of Natural Resources ; *Ecosystem ; *Trees ; Tropical Climate

2015-06-11

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Alleles ; Amino Acid Substitution/genetics ; Animals ; Cattle ; Creutzfeldt-Jakob Syndrome/genetics/prevention & control ; Encephalopathy, Bovine Spongiform/genetics ; Female ; Heterozygote ; Homozygote ; Humans ; Kuru/epidemiology/genetics/prevention & control ; Mice ; Mice, Transgenic ; Papua New Guinea/epidemiology ; Polymorphism, Genetic/*genetics ; PrPSc Proteins/chemistry/genetics/metabolism ; Prion Diseases/epidemiology/*genetics/*prevention & control/transmission ; Prions/chemistry/*genetics/*metabolism/pharmacology

2018-11-15

American Association for the Advancement of Science (AAAS)

2375-2548

Natural Sciences in General

1471-0528

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Forty-seven patients with locally advanced cervical cancer at high risk of relapse received three cycles of chemotherapy with PVB (cisplatin, vinblastine and bleomycin) before definitive local treatment with either radical surgery or radiotherapy. Thirty-one of the 47 patients (66%) responded to initial chemotherapy, and 11 of them have relapsed compared with 13 of the 16 non-responders. Median time to recurrence was 31 weeks for PVB non-responders but has not yet been reached for PVB responders. After a median follow-up of 128 weeks, 14 of the 31 responders (45 %) are alive and disease free compared with 3 of the 16 non-responders (19%). There was a positive correlation between response to chemotherapy and subsequent response to radiotherapy. PVB was in general well tolerated although one death is probably attributable to chemotherapy. A randomized study comparing radiotherapy alone with initial PVB chemotherapy followed by radiotherapy is in progress.

Electronic Resource

1365-2486

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Energy, Environment Protection, Nuclear Power Engineering

Geography

The carbon balance of the world's terrestrial ecosystems is uncertain. Both top-down (atmospheric) and bottom-up (forest inventory and land-use change) approaches have been used to calculate the sign and magnitude of a net terrestrial flux. Different methods often include different processes, however, and comparisons can be misleading. Differences are not necessarily the result of uncertainties or errors, but often result from incomplete accounting inherent in some of the methods. Recent estimates are reviewed here. Overall, a northern mid-latitude carbon sink of approximately 2 Pg C yr−1 appears robust, although the mechanisms responsible are uncertain. Several lines of evidence point to environmentally enhanced rates of carbon accumulation. Other lines suggest that recovery from past disturbances is largely responsible for the sink. The tropics appear to be a small net source of carbon or nearly neutral, and the same uncertainties of mechanism exist. In addition, studies in the tropics do not permit an unequivocal choice between two alternatives: large emissions of carbon from deforestation offset by large sinks in undisturbed forests, or moderate emissions from land-use change with essentially no change in the carbon balance in undisturbed forests. Resolution of these uncertainties is most likely to result from spatially detailed historical reconstructions of land-use change and disturbance in selected northern mid-latitude regions where such data are available, and from systematic monitoring of changes in the area of tropical forests with satellite data of high spatial resolution collected over the last decades and into the future.

Electronic Resource

1365-2486

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Energy, Environment Protection, Nuclear Power Engineering

Geography

The amount of carbon released to the atmosphere as a result of deforestation is determined, in part, by the amount of carbon held in the biomass of the forests converted to other uses. Uncertainty in forest biomass is responsible for much of the uncertainty in current estimates of the flux of carbon from land-use change. In the present contribution several estimates of forest biomass are compared for the Brazilian Amazon, based on spatial interpolations of direct measurements, relationships to climatic variables, and remote sensing data. Three questions were posed: First, do the methods yield similar estimates? Second, do they yield similar spatial patterns of distribution of biomass? And, third, what factors need most attention if we are to predict more accurately the distribution of forest biomass over large areas?   The answer to the first two questions is that estimates of biomass for Brazil's Amazonian forests (including dead and belowground biomass) vary by more than a factor of two, from a low of 39 PgC to a high of 93 PgC. Furthermore, the estimates disagree as to the regions of high and low biomass. The lack of agreement among estimates confirms the need for reliable determination of aboveground biomass over large areas. Potential methods include direct measurement of biomass through forest inventories with improved allometric regression equations, dynamic modelling of forest recovery following observed stand-replacing disturbances, and estimation of aboveground biomass from airborne or satellite-based instruments sensitive to the vertical structure plant canopies.

Electronic Resource

1365-2486

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Energy, Environment Protection, Nuclear Power Engineering

Geography

Changes in land use between 1850 and 1980 are estimated to have increased the global areas in croplands, pastures, and shifting cultivation by 891, 1308, and 30 × 106 ha, respectively, reducing the area of forests by about 600 × 106 ha, releasing about 100 PgC to the atmosphere, and transferring about 23 PgC from live vegetation to dead plant material and wood products. Another 1069 × 106 ha are estimated to have been logged during this period, and the net release of carbon from the combined processes of logging and regrowth contributed 23 PgC to the 100-PgC release. Annual rates of land-use change and associated emissions of carbon have decreased over the last several decades in temperate and boreal zones and have increased in the tropics. The average release of carbon from global changes in land use over the decade of the 1980s Is estimated to have been 1.6 ± 0.7 PgC y−1 almost entirely from the tropics. This estimate of carbon flux is higher than estimates reported in recent summaries because it is limited here to studies concerned only with changes in land use. Other recent analyses, based on data from forest inventories, have reported net accumulations of carbon as high as 1.1 PgC y−1 in temperate and boreal zones. Because the accumulation of carbon in forests may result from natural processes unrelated to land-use change, estimates based on these inventories should be distinguished from estimates based on changes in land use. Both approaches identify terrestrial sinks of carbon. The argument is made here, however, that differences between the two approaches may help identify the location and magnitude of heretofore ‘missing’ sinks. Before different estimates can be used in this way, analyses must consider similar geographical regions and dates, and they must account for the accumulation and loss of carbon in forest products in a consistent fashion.

Electronic Resource

1749-6632

Blackwell Publishing Journal Backfiles 1879-2005

Natural Sciences in General

Electronic Resource

1365-2486

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Energy, Environment Protection, Nuclear Power Engineering

Geography

The net emissions of carbon from forestry and changes in land use in south and southeast Asia were calculated here with a book-keeping model that used rates of land-use change and associated per hectare changes in vegetation and soil to calculate changes in the amount of carbon held in terrestrial ecosystems and wood products. The total release of carbon to the atmosphere over the period 1850–1995 was 43.5 PgC. The clearing of forests for permanent croplands released 33.5 PgC, about 75% of the total. The reduction of biomass in the remaining forests, as a result of shifting cultivation, logging, fuelwood extraction, and associated regrowth, was responsible for a net loss of 11.5 PgC, and the establishment of plantations withdrew from the atmosphere 1.5 PgC, most of it since 1980. Based on comparisons with other estimates, the uncertainty of this long-term flux is estimated to be within ±30%. Reducing this uncertainty will be difficult because of the difficulty of documenting the biomass of forests in existence 〉40 years ago. For the 15-y period 1981–1995, annual emissions averaged 1.07 PgC y–1, about 50% higher than reported for the 1980s in an earlier study. The uncertainty of recent emissions is probably within ± 50% but could be reduced significantly with systematic use of satellite data on changes in forest area. In tropical Asia, the emissions of carbon from land-use change in the 1980s accounted for approximately 75% of the region’s total carbon emissions. Since 1990 rates of deforestation and their associated emissions have declined, while emissions of carbon from combustion of fossil fuels have increased. The net effect has been a reduction in emissions of CO2 from this region since 1990.

Electronic Resource

1365-2486

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Energy, Environment Protection, Nuclear Power Engineering

Geography

The long-term net flux of carbon between terrestrial ecosystems and the atmosphere has been dominated by two factors: changes in the area of forests and per hectare changes in forest biomass resulting from management and regrowth. While these factors are reasonably well documented in countries of the northern mid-latitudes as a result of systematic forest inventories, they are uncertain in the tropics. Recent estimates of carbon emissions from tropical deforestation have focused on the uncertainty in rates of deforestation. By using the same data for biomass, however, these studies have underestimated the total uncertainty of tropical emissions and may have biased the estimates. In particular, regional and country-specific estimates of forest biomass reported by three successive assessments of tropical forest resources by the FAO indicate systematic changes in biomass that have not been taken into account in recent estimates of tropical carbon emissions. The ‘changes’ more likely represent improved information than real on-the-ground changes in carbon storage. In either case, however, the data have a significant effect on current estimates of carbon emissions from the tropics and, hence, on understanding the global carbon balance.

Electronic Resource

1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] The anti-staphylococcal component was extracted from the tape by a number of organic solvents, but not by water. For chromatography, approximately 30 g of tape was extracted with 100 ml. of boiling alcohol and the extract concentrated to a final volume of about 10 ml. About 0.2 ml. of extract was ...

Electronic Resource

1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] Knowledge of carbon exchange between the atmosphere, land and the oceans is important, given that the terrestrial and marine environments are currently absorbing about half of the carbon dioxide that is emitted by fossil-fuel combustion. This carbon uptake is therefore limiting the extent of ...

Electronic Resource

1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] The susceptibility to 2,5-di-tert-amyl-p-benzoquinone (DAQ) of a number of strains of bacteria, the content of ubiquinone and vitamin K of which was known, was discovered by plating suitable dilutions of broth cultures on trypticase soy agar (Baltimore Biological Laboratory, Inc.) containing a ...

Electronic Resource

1572-8838

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Electrical Engineering, Measurement and Control Technology

Abstract The electrochemical removal of Antimony from 1m sulphuric acid in a restrained bed reactor was studied in terms of current, flow velocity, bed depth, bead size and pressure drop. Current efficiencies are quoted as a function of current density and information is given so that they may be calculated in terms of the above variables. Experimentally-obtained limiting current densities are compared with calculated values, using empirical formulae from the literature.

Electronic Resource

1572-8838

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Electrical Engineering, Measurement and Control Technology

Abstract Electrochemical cells, designed to operate with reactants at low concentrations, require special provisions to be made for enhancement of mass transport of the reactants to the electrode surface. The different concepts for doing this in industrial or large-scale cells are reviewed. Examples are given of cells and processes in which these ideas have been used. A comprehensive literature survey of the quantitative relationships pertaining to the different configurations is given. The various cell designs are compared on a quantitative basis, usingi lim, and some advantages and disadvantages are discussed.

Electronic Resource

0008-199X

Linguistics and Literary Studies

REVIEWS

0008-199X

Linguistics and Literary Studies

0008-199X

Linguistics and Literary Studies

REVIEWS