Facility for studying the effects of elevated carbon dioxide concentration and increased temperature on crops

The requirements for the experimental study of the effects of global climate change conditions on plants are outlined. A semi-controlled plant growth facility is described which allows the study of elevated CO2 and temperature, and their interaction on the growth of plants under radiation and temperature conditions similar to the field. During an experiment on winter wheat (cv. Mercia), which ran from December 1990 through to August 1991, the facility maintained mean daytime CO2 concentrations of 363 and 692 cm3 m-3 for targets of 350 and 700 cm3 m-3 respectively. Temperatures were set to follow outside ambient or outside ambient +4-degrees-C, and hourly means were within 0.5-degrees-C of the target for 92% of the time for target temperatures greater than 6-degrees-C. Total photosynthetically active radiation incident on the crop (solar radiation supplemented by artifical light with natural photoperiod) was 2% greater than the total measured outside over the same period

Libraries and open society; Popper, Soros and digital information

This paper examines the role of libraries and information services, in promoting the ‘open society’ espoused by Karl Popper and George Soros. After a brief discussion of the nature of an ‘open society’, the paper covers the role played by provision of knowledge and information, of new technology, particularly the Internet, and of critical thinking and digital literacy in the development of this form of society. Conclusions are drawn for the role of libraries and librarians, with seven general principles suggested: • provision of access to a wide variety of sources without ‘negative’ restriction or censorship • provision of ‘positive’ guidance on sources, based on open and objective criteria • a recognition that a ‘free flow of information’ though essential, is not sufficient • a recognition that provision of factual information, while valuable, is not enough • a need for a specific concern for the effect of new ICTs, and the Internet in particular • promotion of critical thinking and digital literacy • a need for explicit consideration of the ethical values of librarie

Prospects for Constraining Cosmology with the Extragalactic Cosmic Microwave Background Temperature

Observers have demonstrated that it is now feasible to measure the cosmic microwave background (CMB) temperature at high redshifts. We explore the possible constraints on cosmology which might ultimately be derived from such measurements. Besides providing a consistency check on standard and alternative cosmologies, possibilities include: constraints on the inhomogeneity and anisotropy of the universe at intermediate redshift $z ^<_\sim 10$; an independent probe of peculiar motions with respect to the Hubble flow; and constraining the epoch of reionization. We argue that the best possibility is as a probe of peculiar motions. We show, however, that the current measurement uncertainty ($\Delta T= \pm 0.002$K) in the local present absolute CMB temperature imposes intrinsic limits on the use of such CMB temperature measurements as a cosmological probe. At best, anisotropies at intermediate redshift could only be constrained at a level of $^>_\sim 0.1$ and peculiar motions could only be determined to an uncertainty of $^>_\sim 311$ km s$^{-1}$. If the high $z$ CMB temperature can only be measured with a precision comparable to the uncertainty of the local interstellar CMB temperature, then peculiar motions could be determined to an uncertainty of $1101 (1+z)^{-1} [\Delta T_{CMB}(z)/0.01 K] km s^{-1}$.Comment: 8 pages 2 Figures, PRD Submitte

Tmetoceratidae (Ammonitina) fauna from the Gerecse Mts (Hungary)

Abstract Taxonomic and stratigraphic problems of the family Tmetoceratidae and the genera Dumortieria, Catulloceras, Cotteswoldia, Pleydellia and Tmetoceras included in it are briefly discussed. Fifteen species of Tmetoceratidae are described and illustrated from the Upper Toarcian-Aalenian ammonite assemblages of the Gerecse Mts (NE Transdanubian Range, Hungary). The fauna described here is closely allied to the Mediterranean Province of the Mediterranean-Caucasian Realm

Genome-wide Association Analysis in Humans Links Nucleotide Metabolism to Leukocyte Telomere Length

Leukocyte telomere length (LTL) is a heritable biomarker of genomic aging. In this study, we perform a genome-wide meta-analysis of LTL by pooling densely genotyped and imputed association results across large-scale European-descent studies including up to 78,592 individuals. We identify 49 genomic regions at a false dicovery rate (FDR) 350,000 UK Biobank participants suggest that genetically shorter telomere length increases the risk of hypothyroidism and decreases the risk of thyroid cancer, lymphoma, and a range of proliferative conditions. Our results replicate previously reported associations with increased risk of coronary artery disease and lower risk for multiple cancer types. Our findings substantially expand current knowledge on genes that regulate LTL and their impact on human health and disease.Peer reviewe

Toetsingsparameters dijkgrasland

Bevat: Indicatorsoorten dijkgraslandtypen en worteldichtheidbepaling (handmethode)

Carbon dioxide and water vapour exchange from understory species in boreal forest.

Although recent eddy covariance measurements in boreal forests provide CO2 and energy exchange data for the whole ecosystem, very little is known about the role of the understory vegetation. We conducted chamber flux measurements in an Alaskan black spruce forest in order to compare CO2 and water vapour exchange among patches of understory vegetation dominated by feathermoss (Hylocomium), peatmoss (Sphagnum), vascular plants (mainly low shrubs), or lichens. We found large differences among understory vegetation types with respect to midday net CO2 exchange and its seasonal pattern of variation. Sphagnum and vascular-plant plots showed net CO2 uptake, with most uptake on days of high light availability. In contrast, Hylocomium and lichen plots lost CO2 during the middle of the growing season, but showed net uptake at the end of the season when the soil had cooled down. Spatial variation in net CO2 exchange was related more to biotic variables like soil organic matter than to environmental variables. The differences among vegetation types with respect to water vapour fluxes were smaller, because evapotranspiration was more constrained by climatic variables like solar radiation. Net CO2 uptake in Hylocomium plots was negatively related to evapotranspiration, because Hylocomium photosynthesis was very sensitive to evaporative stress, whereas evapotranspiration and net CO2 uptake in Sphagnum were not limited by moisture conditions. These differences suggest that species composition of the understory should be taken into account when discussing understory contributions to CO2 and water vapour exchange. Author Keywords: Climate change; CO2; Evapotranspiration; Hylocomium splendens; Sphagnum capillifolium; Understory vegetatio

Controls on moss evaporation in a boreal black spruce forest

[1] Mosses are an important component of the boreal forest, but little is known about their contribution to ecosystem carbon, water, and energy exchange. We studied the role of mosses in boreal forest evapotranspiration by conducting two experiments in a black spruce forest in Fairbanks, Alaska. Moss evaporation was measured using lysimeters filled with Hylocomium splendens or Sphagnum capillifolium. Microclimate and moisture content were varied by placing the lysimeters in different habitats ( dense forest, open forest, bog), and by manipulating the water supply (no water, natural rainfall, water added). Moss evaporation rates between 1 June and 8 September averaged 0.3, 0.9, and 1.5 mm day(-1) in the dense forest (Hylocomium), open forest (Hylocomium and Sphagnum), and bog ( Sphagnum) respectively. Assuming a total forest evapotranspiration rate of 2 mm day(-1), this study shows that moss evaporation contributes considerably to boreal black spruce forest evapotranspiration. Moss evaporation rates depended strongly on the openness of the forest and to a lesser degree on the density of the vascular plant canopy and on moss species. The strong influence of habitat suggests that microclimate is the primary factor determining moss evaporation rates. Hylocomium evaporation reacted strongly to experimental water additions, indicating that precipitation frequency is an important factor in addition to microclimate for this species. The large moss evaporation rates in this study suggest a potential cooling effect of mosses, of Sphagnum in particular