In vivo assessment of an industrial waste product as a feed additive in dairy cows: Effects of larch (Larix decidua L.) sawdust on blood parameters and milk composition.

Science.gov (United States)

Tedesco, D; Garavaglia, L; Spagnuolo, M S; Pferschy-Wenzig, E M; Bauer, R; Franz, C

2015-12-01

When larch (Larix spp.) is processed in the wood industry, the sawdust is currently disposed of as waste or used as combustible material, even though it is rich in biologically active compounds. In this study the effect of larch sawdust supplementation on blood parameters as well as milk composition was examined in healthy mid-lactating dairy cows. Twenty-four multiparous Italian Friesian dairy cows were assigned to groups receiving either 300 g/day/cow of larch sawdust or a control diet, and treatments were continued for a 20 day period. Milk parameters were unaffected by treatment. A lower plasma total protein concentration was observed and can be attributed to a decrease in globulin concentration. A lower plasma urea concentration was also detected in the larch group. Moreover, biomarkers of liver function were influenced by the treatment. Total bilirubin was lower in larch-treated animals, and cholesterol tended to be lower. In addition, an interaction between day and treatment was observed for very low density lipoprotein. The concentration of other parameters, including reactive oxygen metabolites, superoxide dismutase, glutathione peroxidase and nitrotyrosine, did not differ between treatments. The observed benefits, together with the good palatability, make larch sawdust a promising candidate for the development of beneficial feed supplements for livestock. Further studies will be useful, particularly to evaluate its efficacy in different health conditions. Copyright © 2015 Elsevier Ltd. All rights reserved.

Population structure of larch forests in the Urals

Energy Technology Data Exchange (ETDEWEB)

Putenikhin, V.P.; Farukshina, G.G. [Russian Academy of Sciences, Ufa (Russian Federation). Botanical Garden Inst.

1995-12-31

The variability and population structure of larch (Larix sukaczewii Dyl.) naturally growing in the Urals was studied on the basis of biometric analysis of generative organs. The obtained results point to the existence of 11 phenotypically different local populations of Larix sukaczewii in the Urals. Four populations are identified in the South Urals: Marginal, central, high-mountainous, south-uralian and Bashkircis-uralian. Middle-uralian, Perm cis-uralian, central north-uralian and high-mountainous north-uralian populations are determined in the Middle and the North Urals. Three populations of Larix sukaczewii are identified in the Sub-Polar and the Polar Urals: Subpolar-uralian, Pechora-Thiman cisuralian and polar-uralian. 8 refs, 2 tabs

Population structure of larch forests in the Urals

Energy Technology Data Exchange (ETDEWEB)

Putenikhin, V P; Farukshina, G G [Russian Academy of Sciences, Ufa (Russian Federation). Botanical Garden Inst.

1996-12-31

The variability and population structure of larch (Larix sukaczewii Dyl.) naturally growing in the Urals was studied on the basis of biometric analysis of generative organs. The obtained results point to the existence of 11 phenotypically different local populations of Larix sukaczewii in the Urals. Four populations are identified in the South Urals: Marginal, central, high-mountainous, south-uralian and Bashkircis-uralian. Middle-uralian, Perm cis-uralian, central north-uralian and high-mountainous north-uralian populations are determined in the Middle and the North Urals. Three populations of Larix sukaczewii are identified in the Sub-Polar and the Polar Urals: Subpolar-uralian, Pechora-Thiman cisuralian and polar-uralian. 8 refs, 2 tabs

On the Effect of Thinning on Tree Growth and Stand Structure of White Birch (Betula platyphylla Sukaczev and Siberian Larch (Larix sibirica Ledeb. in Mongolia

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Alexander Gradel

2017-03-01

Full Text Available The forests of North Mongolia are largely dominated either by larch (Larix sibirica Ledeb. or birch (Betula platyphylla Sukaczev. The increasing demand for timber and firewood is currently met by removal of wood from these forest stands. Therefore, silvicultural approaches that account for both utilization and protection are needed. Thinning trials were established in the research area Altansumber, in the mountain forest steppe west of the town of Darkhan. We analyzed the response of non-spatial and spatial structure and growth of birch and larch stands on thinning. Before thinning, spatial tree distribution was largely clumped. Thinning promoted regular tree distribution. Ingrowth of new stems after thinning tended to redirect stand structure towards clumping. Both relative and absolute tree growth and competition were evaluated before, directly after, and three years after the thinning. Competition played a significant role in tree growth before thinning. A reduction in competition after thinning triggered significantly increased growth of both birch and larch. The observed positive growth response was valid in absolute and relative terms. A methodically based forest management strategy, including thinning operations and selective cuttings, could be established, even under the harsh Mongolian conditions. Our findings could initiate the development of broader forest management guidelines for the light-taiga dominated stands.

Intraspecific variability of European larch for wood properties: Preliminary results

Energy Technology Data Exchange (ETDEWEB)

Paques, L.E.; Rozenberg, P. [Institut National de Recherches Agronomiques (INRA), 45 - Olivet (France). Station d`Amelioration des Arbres Forestiers

1995-12-31

Wood properties of several natural populations of European larch (Larix decidua Mill) were determined from samples collected in one replicate of the II. International IUFRO provenance experiment, planted in Brittany in 1959. According to provenances, proportion of heartwood ranges from 35 to 58% of basal area, basic density from 442 to 505 g/dm{sup 3} and Young modulus of elasticity from 8474 to 14522 MPa. Positive correlations between girth and heartwood proportion and between wood density and modulus of elasticity but negative correlations between ring width and both density and MOE have been found both at the individual and at the population levels. Variability between and within provenances is high for two major traits (proportion of heartwood and Young modulus of elasticity) for which a SW - NE gradient is shown. For wood density parameters including pilodyn, a greater homogeneity is observed. Besides a now largely recognized superiority for growth traits, Central European populations from the Sudetan Mountains and Central Poland would also produce wood with better properties. On the reverse, Alpine populations from the French Alps growing at low elevations have a slower growth, a denser wood with less heartwood and less strength. Used as a control, the hybrid larch origin (Larix x eurolepis) represents the best compromise for wood properties with the highest strength but an average wood density and one of the highest proportion of heartwood. These preliminary results must be confirmed from a larger set of provenances and completed with other major wood properties such as durability and shrinkage. 17 refs, 2 figs, 6 tabs

Intraspecific variability of European larch for wood properties: Preliminary results

Energy Technology Data Exchange (ETDEWEB)

Paques, L E; Rozenberg, P [Institut National de Recherches Agronomiques (INRA), 45 - Olivet (France). Station d` Amelioration des Arbres Forestiers

1996-12-31

Wood properties of several natural populations of European larch (Larix decidua Mill) were determined from samples collected in one replicate of the II. International IUFRO provenance experiment, planted in Brittany in 1959. According to provenances, proportion of heartwood ranges from 35 to 58% of basal area, basic density from 442 to 505 g/dm{sup 3} and Young modulus of elasticity from 8474 to 14522 MPa. Positive correlations between girth and heartwood proportion and between wood density and modulus of elasticity but negative correlations between ring width and both density and MOE have been found both at the individual and at the population levels. Variability between and within provenances is high for two major traits (proportion of heartwood and Young modulus of elasticity) for which a SW - NE gradient is shown. For wood density parameters including pilodyn, a greater homogeneity is observed. Besides a now largely recognized superiority for growth traits, Central European populations from the Sudetan Mountains and Central Poland would also produce wood with better properties. On the reverse, Alpine populations from the French Alps growing at low elevations have a slower growth, a denser wood with less heartwood and less strength. Used as a control, the hybrid larch origin (Larix x eurolepis) represents the best compromise for wood properties with the highest strength but an average wood density and one of the highest proportion of heartwood. These preliminary results must be confirmed from a larger set of provenances and completed with other major wood properties such as durability and shrinkage. 17 refs, 2 figs, 6 tabs

Cone and seed production of western larch in response to girdling and nitrogen fertilization - an update

Science.gov (United States)

Russell T. Graham; Jonalea R. Tonn; Theresa B. Jain

1995-01-01

Western larch (Larix occidentalis Nutt.) is a sporadic cone and seed producer. Because the species is such an important component of the -Northern Rocky Mountain forests, methods of increasing seed production are needed. Girdling, fertilizing, and a combination of the two were used on 75-year-old western larch in northern Idaho. Girdling at the base of the live crown...

Container configuration influences western larch and big sagebrush seedling development

Science.gov (United States)

Matthew Mehdi. Aghai

2012-01-01

Big sagebrush (Artemisia tridentata Nutt.), a woody shrub, and western larch (Larix occidentalis Nutt.), a deciduous conifer, are among many western North American species that have suffered a decline in presence and natural regeneration across their native ranges. These species are economically, ecologically, and intrinsically valuable, therefore many current...

Proceedings. Larch genetics and breeding. Research findings and ecological-silvicultural demands

Energy Technology Data Exchange (ETDEWEB)

Martinsson, Owe [ed.

1995-12-31

The genus Larix Mill. (larch) represents a great part of the boreal and alpine forests. Larch species are the most common conifers in Siberia and they have an important role in European and North American forest ecosystems and forest economies. The value of these group of species are expected to increase in the future. There are at least three different reasons for that assumption: 1. Larch has highly appreciated technical wood properties., 2. Intensive cutting during the past three centuries has made larch a threatened group of species in some parts of the world., 3. Increasing access to Siberia will make forestry and forest harvest of larch an important part of the forest economy and ecology. In August 1995 a group of forest scientists gathered under the framework of IUFRO working group S2.02-07 in southern Sweden for exchange of experience in the fields of breeding and silviculture of larch. This proceedings was compiled on the basis of the presentations of this working group. Separate abstracts have been prepared for 12 of the 17 papers

Proceedings. Larch genetics and breeding. Research findings and ecological-silvicultural demands

Energy Technology Data Exchange (ETDEWEB)

Martinsson, Owe [ed.

1996-12-31

The genus Larix Mill. (larch) represents a great part of the boreal and alpine forests. Larch species are the most common conifers in Siberia and they have an important role in European and North American forest ecosystems and forest economies. The value of these group of species are expected to increase in the future. There are at least three different reasons for that assumption: 1. Larch has highly appreciated technical wood properties., 2. Intensive cutting during the past three centuries has made larch a threatened group of species in some parts of the world., 3. Increasing access to Siberia will make forestry and forest harvest of larch an important part of the forest economy and ecology. In August 1995 a group of forest scientists gathered under the framework of IUFRO working group S2.02-07 in southern Sweden for exchange of experience in the fields of breeding and silviculture of larch. This proceedings was compiled on the basis of the presentations of this working group. Separate abstracts have been prepared for 12 of the 17 papers

Stocktype and vegetative competition influences on Pseudotsuga menziesii and Larix occidentalis seedling establishment

Science.gov (United States)

Jeremiah R. Pinto; Bridget A. McNassar; Olga A. Kildisheva; Anthony S. Davis

2018-01-01

Douglas fir (Pseudotsuga menziesii var. glauca (Mayr) Franco), and western larch (Larix occidentalis Nutt.) are species of ecological and commercial importance that occur throughout the Western United States. Effective reforestation of these species relies on successful seedling establishment, which is affected by planting stock quality, stocktype size, and...

Connecting overwintering success of eastern larch beetle to health of tamarack. Chapter 16

Science.gov (United States)

Robert C. Venette; Abigail J. Walter

2012-01-01

Michigan, Wisconsin, Maine, and Minnesota have experienced extensive mortality of tamarack (eastern larch) (Larix laricina). The Minnesota Department of Natural Resources reported tamarack mortality on 54,000 acres of Minnesota forests between 2001 and 2006 (Minnesota Department of Natural Resources 2006). Although the exact cause of tree mortality...

Oxyfluorfen strongly affects Larix occidentalis but minimally affects Sagina procumbens in a bareroot nursery

Science.gov (United States)

R. Kasten Dumroese; Jasmine L. Williams; Jeremy R. Pinto; Peng Zhang

2014-01-01

Our objective was to evaluate oxyfluorfen for control of birdseye pearlwort (Sagina procumbens L.) in a bareroot nursery crop of western larch (Larix occidentalis Nutt.) seedlings. Oxyfluorfen applied at rates up to 0.56 kg a.i./ha in a split-plot experiment with combinations and frequencies of pre- and postemergence sprays gave minimal control of birdseye pearlwort....

Homogenization-assisted cavitation hybrid rotation extraction and macroporous resin enrichment of dihydroquercetin from Larix gmelinii.

Science.gov (United States)

Xia, Yu; Wang, Yinhang; Li, Wei; Ma, Chunhui; Liu, Shouxin

2017-12-01

Cavitation hybrid rotation, which was and is still looked upon as an unavoidable nuisance in the flow systems, for extraction processing intensification of active chemical compounds from natural products. In this study, a homogenization-assisted cavitation hybrid rotation extraction method was applied to extract dihydroquercetin (DHQ) from larch (Larix gmelinii) wood root. The extraction parameters were optimized in single factor experiments with the DHQ extraction yields as the response values. The optimum conditions were as follows: number of extractions, three; ethanol volume fraction for the extraction, 60%; liquid-solid ratio for homogenization, 10mL/g; homogenization time, 8min; liquid-solid ratio for cavitation extraction, 9mL/g, and cavitation extraction time, 35min. Under these conditions, the DHQ content in extract was 4.50±0.02mg/g, and the extraction efficiency was higher than those of traditional techniques. Cavitation can be effectively used to improve the extraction rate by increasing the mass transfer rates and possible rupture of cell wall due to formation of microcavities leading to higher product yields with reduced processing time and solvent consumption. After the extraction process, macroporous resin column chromatography was used to concentrate and purify the DHQ. Three resins were selected from fifteen macroporous resins for further investigation of their performance. Among these resins, AB-8 resin exhibited relatively better adsorption capacities and desorption ratios for DHQ. The ethanol volume fraction of the solutions for sample loading and desorption, and flow rates for loading and desorption were optimized for the macroporous resin column chromatography. Copyright © 2017 Elsevier B.V. All rights reserved.

Nursery cultural practices to achieve targets: A case study in western larch irrigation

Science.gov (United States)

Anthony S. Davis; Robert F. Keefe

2011-01-01

Nursery cultural practices are used to help growers achieve pre-determined size and physiological targets for seedlings. In that regard, irrigation is used to accelerate or slow growth and as a trigger for changing growth phase. In a case study highlighting the effects of irrigation on seedling development, western larch (Larix occidentalis Nutt.) seedlings were grown...

Climate-Induced Larch Growth Response Within the Central Siberian Permafrost Zone

Science.gov (United States)

Kharuk, Viacheslav I.; Ranson, Kenneth J.; Im, Sergei T.; Petrov, Il'ya A.

2015-01-01

Aim: estimation of larch (Larix gmelinii) growth response to current climate changes. Location: permafrost area within the northern part of Central Siberia (approximately 65.8 deg N, 98.5 deg E). Method: analysis of dendrochronological data, climate variables, drought index SPEI, GPP (gross primary production) and EVI vegetation index (both Aqua/MODIS satellite derived), and soil water content anomalies (GRACE satellite measurements of equivalent water thickness anomalies, EWTA). Results: larch tree ring width (TRW) correlated with previous year August precipitation (r = 0.63), snow accumulation (r = 0.61), soil water anomalies (r = 0.79), early summer temperatures and water vapor pressure (r = 0.73 and r = 0.69, respectively), May and June drought index (r = 0.68-0.82). There are significant positive trends of TRW since late 1980s and GPP since the year 2000. Mean TRW increased by about 50%, which is similar to post-Little Ice Age warming. TRW correlated with GPP and EVI of larch stands (r = 0.68-0.69). Main conclusions: within the permafrost zone of central Siberia larch TRW growth is limited by early summer temperatures, available water from snowmelt, water accumulated within soil in the previous year, and permafrost thaw water. Water stress is one of the limiting factors of larch growth. Larch TRW growth and GPP increased during recent decades.

DETERMINATION OF MOISTURE DIFFUSION COEFFICIENT OF LARCH BOARD WITH FINITE DIFFERENCE METHOD

Directory of Open Access Journals (Sweden)

Qiaofang Zhou

2011-04-01

Full Text Available This paper deals with the moisture diffusion coefficient of Dahurian Larch (Larix gmelinii Rupr. by use of the Finite Difference Method (FDM. To obtain moisture distributions the dimensional boards of Dahurian Larch were dried, from which test samples were cut and sliced evenly into 9 pieces in different drying periods, so that moisture distributions at different locations and times across the thickness of Dahurian Larch were obtained with a weighing method. With these experimental data, FDM was used to solve Fick’s one-dimensional unsteady-state diffusion equation, and the moisture diffusion coefficient across the thickness at specified time was obtained. Results indicated that the moisture diffusion coefficient decreased from the surface to the center of the Dahurian Larch wood, and it decreased with decreasing moisture content at constant wood temperature; as the wood temperature increased, the moisture diffusion coefficient increased, and the effect of the wood temperature on the moisture diffusion coefficient was more significant than that of moisture content. Moisture diffusion coefficients were different for the two experiments due to differing diffusivity of the specimens.

Ecological impacts and management strategies for western larch in the face of climate-change

Science.gov (United States)

Gerald E. Rehfeldt; Barry C. Jaquish

2010-01-01

Approximately 185,000 forest inventory and ecological plots from both USA and Canada were used to predict the contemporary distribution of western larch (Larix occidentalis Nutt.) from climate variables. The random forests algorithm, using an 8-variable model, produced an overall error rate of about 2.9 %, nearly all of which consisted of predicting presence at...

Stratification requirements for germination of western larch (Larix occidentalis Nutt.) seed.

Science.gov (United States)

Frank C. Sorenson

1990-01-01

A northeast Washington collection of western larch seeds was stratified for 0,10, 20, 40, and 80 days and incubated at 55, 64, and 73 °F. The germination percentage of filled seeds and speed and uniformity of germination were improved by long stratification, particularly at the lowest incubation temperature. Stratified seeds were also nursery sown in early April and...

Water relations and photosynthetic performance in Larix sibirica growing in the forest-steppe ecotone of northern Mongolia.

Science.gov (United States)

Dulamsuren, Choimaa; Hauck, Markus; Bader, Martin; Osokhjargal, Dalaikhuu; Oyungerel, Shagjjav; Nyambayar, Suran; Runge, Michael; Leuschner, Christoph

2009-01-01

Shoot water relations were studied in Siberian larch (Larix sibirica Ledeb.) trees growing at the borderline between taiga and steppe in northern Mongolia. Larix sibirica is the main tree species in these forests covering 80% of Mongolia's forested area. Minimum shoot water potentials (Psi(m)) close to the point of zero turgor (Psi(0)) repeatedly recorded throughout the growing season suggest that the water relations in L. sibirica were often critical. The Psi(m) varied in close relation to the atmospheric vapor pressure deficit, whereas Psi(0) was correlated with monthly precipitation. Young larch trees growing at the forest line to the steppe were more susceptible to drought than mature trees at the same sites. Furthermore, isolated trees growing on the steppe exhibited lower Psi(m) and recovered to a lower degree from drought overnight than the trees at the forest line. Indications of drought stress in L. sibirica were obtained in two study areas in Mongolia's forest-steppe ecotone: one in the mountain taiga of the western Khentey in northernmost Mongolia, the other in the forest-steppe at the southern distribution limit of L. sibirica on Mt. Bogd Uul, southern Khentey. Larix sibirica growing in riverine taiga with contact to the groundwater table was better water-supplied than the larch trees growing at the forest line to the steppe. Larch trees from the interior of light taiga forests on north-facing slopes, however, exhibited more critical water relations than the trees at the forest line. Frequent drought stress in mature trees and even more in young larch trees at the forest-steppe borderline suggests that L. sibirica does not have the potential to encroach on the steppe under the present climate, except in a sequence of exceptionally moist and cool years. A regression of the present borderline between forest and steppe is likely to occur, as average temperatures are increasing everywhere and precipitation is decreasing regionally in Mongolia's taiga forest

Effect of fall-applied nitrogen on growth, nitrogen storage, and frost hardiness of bareroot Larix olgensis seedlings

Science.gov (United States)

Guolei Li; Yong Liu; Yan Zhu; Qingmei Li; R. Kasten Dumroese

2012-01-01

Nursery response of evergreen trees to fall fertilization has been studied widely, but little attention has been given to deciduous trees. Bareroot Olga Bay larch (Larix olgensis Henry) seedlings were fertilized in the nursery with urea at four rates (0, 30, 60, 90 kg N ha-1), with half of each rate applied on two dates (September 16 and October 1, 2009). The seedlings...

The Effect of Soil Manganese on Japanese Larch (Larix Leptolepis Sieb. and Zucc.) Seedlings in the Greenhouse

Science.gov (United States)

Callie Jo Schweitzer; William E. Sharpe; Pamela J. Edwards

1999-01-01

Preliminary analysis of 9 year old Japanese larch trees and soil subjected to appliitions of triple ambient annual nitrogen (N) and sulfur (S) deposftfon revealed elevated available soil and foliar manganese (Mn) levels and decreased growth compared to controls. A greenhouse study was conducted in which Japanese larch seedlings were grown in geld collected soil...

Effects of Burn Severity and Environmental Conditions on Post-Fire Regeneration in Siberian Larch Forest

OpenAIRE

Thuan Chu; Xulin Guo; Kazuo Takeda

2017-01-01

Post-fire forest regeneration is strongly influenced by abiotic and biotic heterogeneity in the pre- and post-fire environments, including fire regimes, species characteristics, landforms, hydrology, regional climate, and soil properties. Assessing these drivers is key to understanding the long-term effects of fire disturbances on forest succession. We evaluated multiple factors influencing patterns of variability in a post-fire boreal Larch (Larix sibirica) forest in Siberia. A time-series o...

Fire Return Interval Within the Northern Boundary of the Larch Forest

Science.gov (United States)

Kharuk, V. I.; Dvinskaya, M. L.; Ranson, K. J.

2011-01-01

Larch (Larix spp.) dominant forests compose a large proportion of the forests of Russia (i.e., about 40% of forested areas). These forests range from the Yenisei ridge on the west to the Pacific Ocean on the east, and from Lake Baikal on the south to the 73rd parallel in the north. Larch stands comprise the world s northern most forest at Ary-Mas (72 deg 28' N, 102 deg 15' E). Larch dominated forests occupy about 70% of the permafrost areas in Siberia. Larch forms high closure stands as well as open forests, and is found mainly over permafrost, where other tree species barely survive. Wildfires are typical for this territory with the majority occurring as ground fires due to low crown closure. Due to the thin active layer in permafrost soils and a dense lichen-moss cover, ground fires may cause stand mortality. The vast areas of larch-dominant forests is generally considered as a "carbon sink"; however, positive long-term temperature trends at higher latitudes are expected to result in an increase of fire frequency, and thus may convert this area to a source for greenhouse gases. There are recent observations regarding the increase of fire frequency within non-protected territories. Surprisingly, there are few publications on fire chronoseqences for the huge forested territory between the Ural Mountains and the Pacific Ocean. Also there is a general understanding that bimodal (late spring -- early summer and late summer-beginning of fall) fire seasonal distribution in the south becomes uni-modal (late spring -- early summer) in the north. The purpose of this study is to investigate the wildfire history at the northern edge of the zone of larch dominance.

The Alleviation of Nutrient Deficiency Symptoms in Changbai Larch (Larix olgensis Seedlings by the Application of Exogenous Organic Acids

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Jinfeng Song

2016-09-01

Full Text Available Exogenous organic acids are beneficial in protecting plants from the stress of heavy metal toxins (e.g., Pb in soils. This work focuses on the potential role of organic acids in protecting Changbai larch (Larix olgensis seedlings from the stress of growing in nutrient deficient soil. The seedlings were planted in a nutrient rich or deficient soil (A1 horizon of a Haplic Cambisol without organic acid as the nutrient rich control, or fully-mixed A1 + B horizons in a proportion of 1:2 as deficient in pots in a greenhouse. In A1 + B horizons the seedlings were treated daily with concentrations of oxalic or citric acid (OA or CA at a rate approximately equivalent to 0, 0.04, 0.2, 1.0, or 2.0 mmol·kg−1 of soil for 10, 20, and 30 days. Nutrient deficiency stressed the seedlings as indicated by lipid peroxidation and malondialdehyde (MDA content in leaves significantly increasing, and superoxide dismutase (SOD activities, proline, photosynthetic pigment contents, and chlorophyll fluorescence (Fv/Fm decreasing. The stress increased in controls over the application periods. When nutrient deficient plants were exposed to an organic acid (especially 5.0 or 10.0 mmol·L−1 for 20 days, the stress as indicated by the physiological parameters was reversed, and survival rate of seedlings, and biomass of root, stem, and leaf significantly increased; CA was more effective than OA. The results demonstrate that exogenous organic acids alleviate nutrient deficiency-induced oxidative injuries and improve the tolerance of L. olgensis seedlings to nutrient deficiency.

Larch dwarf mistletoe not found on alpine larch

Science.gov (United States)

Robert L. Mathiasen; Brian W. Geils; Clinton E. Carlson; Frank G. Hawksworth

1995-01-01

Reports of larch dwarf mistletoe parasitizing alpine larch are based on two collections of this host/parasite combination made by J.R. Weir in Montana during the early 1900s. Examination of host material from these collections indicates that the host is western larch, not alpine larch as previously reported. Attempts to locate larch dwarf mistletoe on alpine larch were...

Ectomycorrhizal colonization and growth of the hybrid larch F1 under elevated CO2 and O3

International Nuclear Information System (INIS)

Wang, Xiaona; Qu, Laiye; Mao, Qiaozhi; Watanabe, Makoto; Hoshika, Yasutomo; Koyama, Akihiro; Kawaguchi, Korin; Tamai, Yutaka; Koike, Takayoshi

2015-01-01

We studied the colonization of ectomycorrhizal fungi and species abundance of a hybrid larch (F 1 ) under elevated CO 2 and O 3. Two-year-old seedlings were planted in an Open-Top-Chamber system with treatments: Control (O 3  < 6 nmol/mol), O 3 (60 nmol/mol), CO 2 (600 μmol/mol), and CO 2  + O 3 . After two growing seasons, ectomycorrhiza (ECM) colonization and root biomass increased under elevated CO 2 . Additionally, O 3 impaired ECM colonization and species richness, and reduced stem biomass. However, there was no clear inhibition of photosynthetic capacity by O 3 . Concentrations of Al, Fe, Mo, and P in needles were reduced by O 3 , while K and Mg in the roots increased. This might explain the distinct change in ECM colonization rate and diversity. No effects of combined fumigation were observed in any parameters except the P concentration in needles. The tolerance of F 1 to O 3 might potentially be related to a shift in ECM community structure. - Highlights: • Elevated CO 2 enhanced growth of hybrid larch F 1 (F 1 ). • ECM colonization rate and species richness of ECM were reduced by O 3 . • Species abundance of ECM community differed between O 3 and control. • F 1 potentially resisted O 3 impacts via specific selection of Suillus spp. for element uptake. - Elevated CO 2 moderated the negative effects of O 3 on the growth of hybrid larch F 1 , by stimulating ectomycorrhizas and nutrient uptake

Larix decidua Bark as a Source of Phytoconstituents: An LC-MS Study

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Valeria Baldan

2017-11-01

Full Text Available Larix decidua bark is a waste of the timber industry and is widely diffused in Northern Italy. This material can be considered a good source of antioxidants and phytoconstituents with possible use in cosmetic or nutraceutical products. In this study, simple extraction of larch bark was performed using mixtures of ethanol/water. Furthermore, the phytochemical composition of larch bark extract was studied using LC-MSn methods and the main constituents were identified as flavonoids, spiro-polyphenols, and procyanidins. To confirm the identification by LC-MS semi-preparative HPLC was performed in order to isolate the main constituents and verify the structures by 1H-NMR. Antioxidant properties were studied using an in vitro approach combining DPPH assay and LC-MS in order to establish different roles of the various classes of phytochemicasl of the extract. DPPH activity of some of the isolated compounds was also assessed. The overall results indicate this waste material as a good source of antioxidant compounds, mainly procyanidins, whichresulted the most active constituents in the DPPH assay.

Genetic variability of woolly aphid (Adelges laricis Vall.) resistance in European larch (Larix decidua Mill.)

Energy Technology Data Exchange (ETDEWEB)

Blada, I. [Forest Research Inst., Bucharest (Romania)

1995-12-31

One hundred and eleven clones of European larch were exposed to the woolly aphid and then outplanted in three locations using a randomized complete block design. At ages 11 and 19 years resistance was measured on 102 clones at 2 locations. Highly significant genetic differences were observed among the clones at both locations and at both ages. Highly significant clone x location, clone x location x age interactions were also observed. Differences between the most resistant and most susceptible clones was 483%. Sufficient genetic variation for a breeding program was present. Broad-sense heritability estimates for Adelges resistance varied by location. Significant age to age, location to location and age to location phenotypic correlation for resistance were found. Larch resistance seems to be under polygenic control. A substantial genetic gain could be achieved by selecting the best clones and using vegetative propagation, including somaclonal embryogenesis, for multiplication. 23 refs, 2 figs, 8 tabs

Genetic variability of woolly aphid (Adelges laricis Vall.) resistance in European larch (Larix decidua Mill.)

Energy Technology Data Exchange (ETDEWEB)

Blada, I [Forest Research Inst., Bucharest (Romania)

1996-12-31

One hundred and eleven clones of European larch were exposed to the woolly aphid and then outplanted in three locations using a randomized complete block design. At ages 11 and 19 years resistance was measured on 102 clones at 2 locations. Highly significant genetic differences were observed among the clones at both locations and at both ages. Highly significant clone x location, clone x location x age interactions were also observed. Differences between the most resistant and most susceptible clones was 483%. Sufficient genetic variation for a breeding program was present. Broad-sense heritability estimates for Adelges resistance varied by location. Significant age to age, location to location and age to location phenotypic correlation for resistance were found. Larch resistance seems to be under polygenic control. A substantial genetic gain could be achieved by selecting the best clones and using vegetative propagation, including somaclonal embryogenesis, for multiplication. 23 refs, 2 figs, 8 tabs

Spatial variations in larch needle and soil δ15N at a forest-grassland boundary in northern Mongolia.

Science.gov (United States)

Fujiyoshi, Lei; Sugimoto, Atsuko; Tsukuura, Akemi; Kitayama, Asami; Lopez Caceres, M Larry; Mijidsuren, Byambasuren; Saraadanbazar, Ariunaa; Tsujimura, Maki

2017-03-01

The spatial patterns of plant and soil δ 15 N and associated processes in the N cycle were investigated at a forest-grassland boundary in northern Mongolia. Needles of Larix sibirica Ledeb. and soils collected from two study areas were analysed to calculate the differences in δ 15 N between needle and soil (Δδ 15 N). Δδ 15 N showed a clear variation, ranging from -8 ‰ in the forest to -2 ‰ in the grassland boundary, and corresponded to the accumulation of organic layer. In the forest, the separation of available N produced in the soil with 15 N-depleted N uptake by larch and 15 N-enriched N immobilization by microorganisms was proposed to cause large Δδ 15 N, whereas in the grassland boundary, small Δδ 15 N was explained by the transport of the most available N into larch. The divergence of available N between larch and microorganisms in the soil, and the accumulation of diverged N in the organic layer control the variation in Δδ 15 N.

Climate-Driven Changes Within the Larch Forest of Northern Siberia

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Kharuk, V.

2015-12-01

Thanks to the support of NASA's Carbon Cycle and Ecosystem Focus Area programs, joint NASA/ Siberian Branch of the Russian Academy of Sciences studies have been conducted throughout Siberia. The overall objective has been to obtain field and satellite measurements to examine carbon stocks and track changes in forests across this vast area. In this presentation, we discuss some of the finding from this 25+ year collaboration' i.e., observed climate-driven changes within larch communities in northern Siberia. Field measurements and satellite data, including Terra/MODIS, Landsat, GRACE and QuickBird were used for analysis of forest conditions. The following results will be discussed. (1). At the northern limit of larch (Larix gmelinii) range (i.e.,~72°N) tree mortality was observed during the cooling period from the 16th century to the beginning of the 19th century. Post- Little Ice Age (LIA) trees re-establishment followed warming temperatures by the middle of the19th century. The current tree line has recovered to the pre-LIA line location although tree heights and stand densities are comparatively lower. The mean rate of upward migration was found to be 0.35 m yr-1 (with a range of 0.21-0.58). (2) The migration of the "dark needle conifers" (DNC: Abies sibirica, Pinus sibirica, Picea obovata) into the southern margin zone of larch dominated forest was documented. Meanwhile, within the traditional DNC range decline and mortality of both Siberian pine and fir were observed and attributed, primarily, due to an increased drought. (3) Within Central Siberia larch growth is limited by early summer temperatures and available water from thawing permafrost. Larch tree ring width (TRW) correlated with early summer temperatures and water vapor pressure (r = 0.73 and r = 0.69, respectively), drought (SPEI; r = 0.68-0.82), snow accumulation (r = 0.61), previous year precipitation (r = 0.63) and soil water anomalies (r = 0.79). Larch TRW growth and Gross Primary Productivity

Simulating topographic controls on the abundance of larch forest in eastern Siberia, and its consequences under changing climate

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Sato, H.; Kobayashi, H.

2017-12-01

In eastern Siberia, larches (Larix spp.) often exist in pure stands, constructing the world's largest coniferous forest, of which changes can significantly affect the earth's albedo and the global carbon balance. Our previous studies tried to reconstruct this vegetation, aiming to forecast its structures and functions under changing climate (1, 2). In previous studies of simulating vegetation at large geographical scales, the examining area is divided into coarse grid cells such as 0.5 × 0.5 degree resolution, and topographical heterogeneities within each grid cell are just ignored. However, in Siberian larch area, which is located on the environmental edge of existence of forest ecosystem, abundance of larch trees largely depends on topographic condition at the scale of tens to hundreds meters. In our preliminary analysis, we found a quantitative pattern that topographic properties controls the abundance of larch forest via both drought and flooding stresses in eastern Siberia. We, therefore, refined the hydrological sub-model of our dynamic vegetation model SEIB-DGVM, and validated whether the modified model can reconstruct the pattern, examined its impact on the estimation of biomass and vegetation productivity under the current and forecasted future climatic conditions. -- References --1. Sato, H., et al. (2010). "Simulation study of the vegetation structure and function in eastern Siberian larch forests using the individual-based vegetation model SEIB-DGVM." Forest Ecology and Management 259(3): 301-311. 2. Sato, H., et al. (2016). "Endurance of larch forest ecosystems in eastern Siberia under warming trends." Ecology and Evolution

A LARCH BIOREFINERY: INFLUENCE OF WASHING AND PS CHARGE ON PRE-EXTRACTION PSAQ PULPING

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Hanna S. Hörhammer

2012-06-01

Full Text Available This study deals with a biorefinery concept based on larch wood. Wood chips of Siberian larch (Larix sibirica Lebed. were treated with water before pulping at the optimal pre-extraction (PE condition of 150 °C and 90 minutes. Through PE, about 12.4% of the wood mass is dissolved, mainly from the arabinogalactan hemicellulose component. Fermentation of the hemicellulose-rich larch extract with Bacillus coagulans resulted in consumption of all C6 and C5 sugars and produced lactic acid in high yield. PE before pulping resulted in lower (4 to 5% pulp yield than for control kraft pulps. However, the pulp yield loss may be reduced by addition of polysulfide (PS and anthraquinone (AQ. The present study focuses on the effect of the degree of washing of the extracted chips and that of the PS charge in PSAQ pulping on the final properties of the pulp. Three different levels of washing and three different PS charges were tested. The characteristics of the extract, wash water, pulp, and black liquor samples were determined. The amount of sugars in the combined stream of collected extract and wash water obtained by mild washing was 10.2% on o.d. wood.

Effects of Burn Severity and Environmental Conditions on Post-Fire Regeneration in Siberian Larch Forest

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Thuan Chu

2017-03-01

Full Text Available Post-fire forest regeneration is strongly influenced by abiotic and biotic heterogeneity in the pre- and post-fire environments, including fire regimes, species characteristics, landforms, hydrology, regional climate, and soil properties. Assessing these drivers is key to understanding the long-term effects of fire disturbances on forest succession. We evaluated multiple factors influencing patterns of variability in a post-fire boreal Larch (Larix sibirica forest in Siberia. A time-series of remote sensing images was analyzed to estimate post-fire recovery as a response variable across the burned area in 1996. Our results suggested that burn severity and water content were primary controllers of both Larch forest recruitment and green vegetation cover as defined by the forest recovery index (FRI and the fractional vegetation cover (FVC, respectively. We found a high rate of Larch forest recruitment in sites of moderate burn severity, while a more severe burn was the preferable condition for quick occupation by vegetation that included early seral communities of shrubs, grasses, conifers and broadleaf trees. Sites close to water and that received higher solar energy during the summer months showed a higher rate of both recovery types, defined by the FRI and FVC, dependent on burn severity. In addition to these factors, topographic variables and pre-fire condition were important predictors of post-fire forest patterns. These results have direct implications for the post-fire forest management in the Siberian boreal Larch region.

Linking tree demography to climate change feedbacks: fire, larch forests, and carbon pools of the Siberian Arctic

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Alexander, H. D.; Loranty, M. M.; Natali, S.; Pena, H., III; Ludwig, S.; Spektor, V.; Davydov, S. P.; Zimov, N.; Mack, M. C.

2017-12-01

Fire severity is increasing in larch forests of the Siberian Arctic as climate warms, and initial fire impacts on tree demographic processes could be an especially important determinant of long-term forest structure and carbon (C) dynamics. We hypothesized that (1) larch forest regrowth post-fire is largely determined by residual soil organic layer (SOL) depth because of the SOL's role as a seedbed and thermal regulator, and (2) changes in post-fire larch recruitment impact C accumulation through stand density impacts on understory microclimate and permafrost thaw. We tested these hypotheses by (1) experimentally creating a soil burn severity gradient in a Cajander larch (Larix cajanderi Mayr.) forest near Cherskiy, Russia and (2) quantifying C pools across a stand density gradient within a 75-year old fire scar. From 2012-2015, we added larch seeds to plots burned at different severities and monitored recruitment along with permafrost and active layer (i.e., subject to annual freeze-thaw) conditions (SOL depth, temperature, moisture, and thaw depth). Across the density gradient, we inventoried larch trees and harvested ground-layer vegetation to estimate aboveground contribution to C pools. We quantified woody debris C pools and sampled belowground C pools (soil, fine roots, and coarse roots) in the organic + upper (0-10 cm) mineral soil. Larch recruits were rare in unburned and low severity plots, but a total of 6 new germinants m-2 were tallied in moderate and high severity plots during the study. Seedling survival for > 1 year was only 40 and 25% on moderate and high severity treatments, respectively, but yielded net larch recruitment of 2 seedlings m-2, compared to 0.3 seedlings m-2 on low severity plots. Density of both total and established recruits increased with decreasing residual SOL depth, which correlated with increased soil temperature, moisture, and thaw depth. At 75-year post-fire, total C pools increased with increased larch density, largely due to

Isolation, characterization and expression analysis of the BABY BOOM (BBM) gene from Larix kaempferi × L. olgensis during adventitious rooting.

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Li, Kui-Peng; Sun, Xiao-Mei; Han, Hua; Zhang, Shou-Gong

2014-11-10

The full-length cDNA and genomic sequences of the BABY BOOM (BBM) gene, designated LkBBM, were isolated from Larix kaempferi × Larix olgensis. The 3324 bp cDNA was cloned and its open reading frame (ORF) consists of 2370 nucleotides. The deduced 789 amino acid protein contains two AP2 domains and a BBM specific motif. Four conserved motifs between BBM and PLT were identified, which may be conducive to the similar function of BBM and PLT. The three dimensional (3D) structure of LkBBM was predicted and β-sheets in the AP2-R2 domain of LkBBM might recognize the specific base pairs in the major groove. Analysis of the LkBBM gene structure indicates that the gene has eight introns and nine exons. In the 5'-flanking promoter region of LkBBM, many important potential cis-acting elements were identified, such as the TATABOX5 element (a functional TATA element), ROOTMOTIFTAPOX1 element (element of root specificity), AUXREPSIAA4 element (element involved in auxin responsiveness and gene expression in root meristem), MYB1AT element (element involved in MYB recognition), ARR1AT element (element involved in cytokinin responsiveness), GARE1OSREP1 element (element involved in gibberellin responsiveness) and PYRIMIDINEBOXHVEPB1 element (element involved in abscisic acid responsiveness), which all suggested that the expression of LkBBM is highly regulated. Compared with gene expression levels in the stem, stem tip and leaf, LkBBM shows a specific expression in the root, which indicates that LkBBM plays a key role in regulating the development and growth of root in larch. In the processing of larch adventitious root formation, LkBBM started to express on the eighth day after rooting treatment and its transcript level increased continuously afterwards. According to the gene characteristics, LkBBM is proposed as a molecular marker for root primordia of larch, and the initial period of LkBBM expression may be the formation period of root primordia in the processing of adventitious

Time since death and decay rate constants of Norway spruce and European larch deadwood in subalpine forests determined using dendrochronology and radiocarbon dating

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Petrillo, Marta; Cherubini, Paolo; Fravolini, Giulia; Marchetti, Marco; Ascher-Jenull, Judith; Schärer, Michael; Synal, Hans-Arno; Bertoldi, Daniela; Camin, Federica; Larcher, Roberto; Egli, Markus

2016-03-01

Due to the large size (e.g. sections of tree trunks) and highly heterogeneous spatial distribution of deadwood, the timescales involved in the coarse woody debris (CWD) decay of Picea abies (L.) Karst. and Larix decidua Mill. in Alpine forests are largely unknown. We investigated the CWD decay dynamics in an Alpine valley in Italy using the chronosequence approach and the five-decay class system that is based on a macromorphological assessment. For the decay classes 1-3, most of the dendrochronological samples were cross-dated to assess the time that had elapsed since tree death, but for decay classes 4 and 5 (poorly preserved tree rings) radiocarbon dating was used. In addition, density, cellulose, and lignin data were measured for the dated CWD. The decay rate constants for spruce and larch were estimated on the basis of the density loss using a single negative exponential model, a regression approach, and the stage-based matrix model. In the decay classes 1-3, the ages of the CWD were similar and varied between 1 and 54 years for spruce and 3 and 40 years for larch, with no significant differences between the classes; classes 1-3 are therefore not indicative of deadwood age. This seems to be due to a time lag between the death of a standing tree and its contact with the soil. We found distinct tree-species-specific differences in decay classes 4 and 5, with larch CWD reaching an average age of 210 years in class 5 and spruce only 77 years. The mean CWD rate constants were estimated to be in the range 0.018 to 0.022 y-1 for spruce and to about 0.012 y-1 for larch. Snapshot sampling (chronosequences) may overestimate the age and mean residence time of CWD. No sampling bias was, however, detectable using the stage-based matrix model. Cellulose and lignin time trends could be derived on the basis of the ages of the CWD. The half-lives for cellulose were 21 years for spruce and 50 years for larch. The half-life of lignin is considerably higher and may be more than

Stocktype and Vegetative Competition Influences on Pseudotsuga menziesii and Larix occidentalis Seedling Establishment

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Jeremiah R. Pinto

2018-04-01

Full Text Available Douglas fir (Pseudotsuga menziesii var. glauca (Mayr Franco, and western larch (Larix occidentalis Nutt. are species of ecological and commercial importance that occur throughout the Western United States. Effective reforestation of these species relies on successful seedling establishment, which is affected by planting stock quality, stocktype size, and site preparation techniques. This study examined the effects of container volume (80, 130, 200, and 250 cm3 and vegetative competition on seedling survival and physiological and morphological responses for two years, post-outplanting. Glyphosate application (GS and grass planting (HC were used to achieve low and high levels of competition. For all measured attributes, the container volume × vegetative competition was not significant. Mortality was strongly influenced by competition, with higher mortality observed for Douglas fir and western larch planted in HC plots one (28% and 98% and two (61% and 99% years following outplanting. When competition was controlled, seedlings of both species exhibited greater net photosynthesis (>9 μmol m−2 s−1, greater predawn water potential (>−0.35 MPa, and lower mortality (2–3% following one year in the field, indicating establishment success. The 80 cm3 stocktype remained significantly smaller and exhibited lower growth rates for the duration of the study, while all other stocktypes were statistically similar. Our results demonstrate the importance of controlling vegetative competition regardless of stocktype, especially for western larch, and suggest that benefits to post-planting seedling physiology and growth in relation to container size plateau beyond 130 cm3 among the investigated stocktypes.

A Physicochemical and Pharmacological Study of the Newly Synthesized Complex of Albendazole and the Polysaccharide Arabinogalactan from Larch Wood.

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Chistyachenko, Yulia S; Meteleva, Elizaveta S; Pakharukova, Maria Y; Katokhin, Aleksey V; Khvostov, Mikhail V; Varlamova, Anastasiya I; Glamazdin, Igor I; Khalikov, Salavat S; Polyakov, Nikolay E; Arkhipov, Ivan A; Tolstikova, Tatyana G; Mordvinov, Viatcheslav A; Dushkin, Alexander V; Lyakhov, Nikolay Z

2015-01-01

Inclusion complexes of albendazole (ABZ) with the polysaccharide arabinogalactan from larch wood Larix sibirica and Larix gmelinii were synthesized using a solid-state mechanochemical technology. We investigated physicochemical properties of the synthesized complexes in the solid state and in aqueous solutions as well as their anthelmintic activity against Trichinella spiralis, Hymenolepis nаna, Fasciola hepatica, Opisthorchis felineus, and mixed nematodoses of sheep. Formation of the complexes was demonstrated by means of intrinsic solubility and the NMR relaxation method. The mechanochemically synthesized complexes were more stable in comparison with the complex produced by mixing solutions of the components. The complexes of ABZ showed anthelmintic activity at 10-fold lower doses than did free ABZ. The complexes also showed lower acute toxicity and hepatotoxicity. These results suggest that it is possible to design new drugs on the basis of the ABZ:arabinogalactan complex that are safer and more effective than albendazole.

Tracing fresh assimilates through Larix decidua exposed to elevated CO₂ and soil warming at the alpine treeline using compound-specific stable isotope analysis.

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Streit, Kathrin; Rinne, Katja T; Hagedorn, Frank; Dawes, Melissa A; Saurer, Matthias; Hoch, Günter; Werner, Roland A; Buchmann, Nina; Siegwolf, Rolf T W

2013-02-01

How will carbon source-sink relations of 35-yr-old larch trees (Larix decidua) at the alpine treeline respond to changes in atmospheric CO(2) and climate? We evaluated the effects of previously elevated CO(2) concentrations (9 yr, 580 ppm, ended the previous season) and ongoing soil warming (4 yr, + 4°C). Larch branches were pulse labeled (50 at% (13)CO(2)) in July 2010 to trace fresh assimilates through tissues (buds, needles, bark and wood) and non-structural carbon compounds (NCC; starch, lipids, individual sugars) using compound-specific isotope analysis. Nine years of elevated CO(2) did not lead to increased NCC concentrations, nor did soil warming increase NCC transfer velocities. By contrast, we found slower transfer velocities and higher NCC concentrations than reported in the literature for lowland larch. As a result of low dilution with older carbon, sucrose and glucose showed the highest maximum (13)C labels, whereas labels were lower for starch, lipids and pinitol. Label residence times in needles were shorter for sucrose and starch (c. 2 d) than for glucose (c. 6 d). Although our treatments showed no persistent effect on larch carbon relations, low temperature at high altitudes clearly induced a limitation of sink activities (growth, respiration, root exudation), expressed in slower carbon transfer and higher NCC concentrations. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

cDNA cloning, genomic organization and expression analysis during somatic embryogenesis of the translationally controlled tumor protein (TCTP) gene from Japanese larch (Larix leptolepis).

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Zhang, Li-Feng; Li, Wan-Feng; Han, Su-Ying; Yang, Wen-Hua; Qi, Li-Wang

2013-10-15

A full-length cDNA and genomic sequences of a translationally controlled tumor protein (TCTP) gene were isolated from Japanese larch (Larix leptolepis) and designated LaTCTP. The length of the cDNA was 1, 043 bp and contained a 504 bp open reading frame that encodes a predicted protein of 167 amino acids, characterized by two signature sequences of the TCTP protein family. Analysis of the LaTCTP gene structure indicated four introns and five exons, and it is the largest of all currently known TCTP genes in plants. The 5'-flanking promoter region of LaTCTP was cloned using an improved TAIL-PCR technique. In this region we identified many important potential cis-acting elements, such as a Box-W1 (fungal elicitor responsive element), a CAT-box (cis-acting regulatory element related to meristem expression), a CGTCA-motif (cis-acting regulatory element involved in MeJA-responsiveness), a GT1-motif (light responsive element), a Skn-1-motif (cis-acting regulatory element required for endosperm expression) and a TGA-element (auxin-responsive element), suggesting that expression of LaTCTP is highly regulated. Expression analysis demonstrated ubiquitous localization of LaTCTP mRNA in the roots, stems and needles, high mRNA levels in the embryonal-suspensor mass (ESM), browning embryogenic cultures and mature somatic embryos, and low levels of mRNA at day five during somatic embryogenesis. We suggest that LaTCTP might participate in the regulation of somatic embryo development. These results provide a theoretical basis for understanding the molecular regulatory mechanism of LaTCTP and lay the foundation for artificial regulation of somatic embryogenesis. © 2013.

Plasticity in gas-exchange physiology of mature Scots pine and European larch drive short- and long-term adjustments to changes in water availability.

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Feichtinger, Linda M; Siegwolf, Rolf T W; Gessler, Arthur; Buchmann, Nina; Lévesque, Mathieu; Rigling, Andreas

2017-09-01

Adjustment mechanisms of trees to changes in soil-water availability over long periods are poorly understood, but crucial to improve estimates of forest development in a changing climate. We compared mature trees of Scots pine (Pinus sylvestris) and European larch (Larix decidua) growing along water-permeable channels (irrigated) and under natural conditions (control) at three sites in inner-Alpine dry valleys. At two sites, the irrigation had been stopped in the 1980s. We combined measurements of basal area increment (BAI), tree height and gas-exchange physiology (Δ 13 C) for the period 1970-2009. At one site, the Δ 13 C of irrigated pine trees was higher than that of the control in all years, while at the other sites, it differed in pine and larch only in years with dry climatic conditions. During the first decade after the sudden change in water availability, the BAI and Δ 13 C of originally irrigated pine and larch trees decreased instantly, but subsequently reached higher levels than those of the control by 2009 (15 years afterwards). We found a high plasticity in the gas-exchange physiology of pine and larch and site-specific responses to changes in water availability. Our study highlights the ability of trees to adjust to new conditions, thus showing high resilience. © 2017 John Wiley & Sons Ltd.

Growth characteristics of natural and planted Dahurian larch in northeast China

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B. Jia

2018-04-01

Full Text Available Dahurian larch (Larix gmelinii Rupr. is the dominant species in both natural and planted forests in northeast China, which is situated in the southernmost part of the global boreal forest biome and is undergoing great climatically induced changes. Published studies (1965–2015 on tree above-ground growth of Dahurian larch forests in northeast China were collected in this study and critically reviewed, and a comprehensive growth data set was developed from 122 sites, which are distributed between 40.85 and 53.47° N in latitude, between 118.20 and 133.70° E in longitude and between 130 and 1260 m in altitude. The data set is composed of 743 entries and includes growth data (mean tree height, mean diameter at breast height (DBH, mean tree volume and/or stand volume and associated information, i.e., geographical location (latitude, longitude, altitude, aspect and slope, climate (mean annual temperature (MAT and mean annual precipitation (MAP, stand description (origin, stand age, stand density and canopy density and sample regime (observation year, plot area and plot number. It provides a quantitative reference for plantation management practices and boreal forest growth prediction under future climate change. The data set is freely available for noncommercial scientific applications, and the DOI for the data is https://doi.org/10.1594/PANGAEA.880984.

Growth characteristics of natural and planted Dahurian larch in northeast China

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Jia, Bingrui; Zhou, Guangsheng

2018-04-01

Dahurian larch (Larix gmelinii Rupr.) is the dominant species in both natural and planted forests in northeast China, which is situated in the southernmost part of the global boreal forest biome and is undergoing great climatically induced changes. Published studies (1965-2015) on tree above-ground growth of Dahurian larch forests in northeast China were collected in this study and critically reviewed, and a comprehensive growth data set was developed from 122 sites, which are distributed between 40.85 and 53.47° N in latitude, between 118.20 and 133.70° E in longitude and between 130 and 1260 m in altitude. The data set is composed of 743 entries and includes growth data (mean tree height, mean diameter at breast height (DBH), mean tree volume and/or stand volume) and associated information, i.e., geographical location (latitude, longitude, altitude, aspect and slope), climate (mean annual temperature (MAT) and mean annual precipitation (MAP)), stand description (origin, stand age, stand density and canopy density) and sample regime (observation year, plot area and plot number). It provides a quantitative reference for plantation management practices and boreal forest growth prediction under future climate change. The data set is freely available for noncommercial scientific applications, and the DOI for the data is https://doi.org/10.1594/PANGAEA.880984" target="_blank">https://doi.org/10.1594/PANGAEA.880984.

Long-term development of nursing mixtures of Sitka spruce and larch species in an experiment in northern Scotland

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William L. Mason

2014-12-01

Full Text Available Aim of the study: An experiment was established in 1966 to compare the growth and development of 50: 50 mixtures of Sitka spruce (Picea sitchensis with either Japanese larch (Larix kaempferi or tamarack (L. laricina with that found in pure plots of Sitka spruce. The site was one of moderate nitrogen availability where the presence of heather (Calluna vulgaris could be expected to limit the growth ofSitka spruce.Area of the study: North-east Scotland.Material and methods: There were different patterns of spruce growth in the pure plots and in the mixtures, with faster spruce growth in mixture in the years approaching and immediately following canopy closure (i.e. ages 15-25. Foliage analysis suggested that this was linked with improved nitrogen status of spruce trees in the mixed compared to the pure plots.Main results: At years 20 and 25 there were significant differences in height, diameter, and basal area between treatments, with the largest basal area being found in the Japanese larch/Sitka spruce mixtures, indicative of overyielding in the mixed plots. However, when the experiment was clearfelled at 41 years of age, all treatments had self-thinned to produce spruce dominated stands of similar height with only an occasional larch tree surviving in plots that were originally 50:50 mixtures.Research highlights: There were no differences between treatments in basal area, harvested volume or sawlog outturn after 41 years. These results can be interpreted as showing facilitation between the larch and the spruce during the establishment phase followed by competition for light once canopy closure had occurred.Keywords: Mixed stand dynamics; facilitation; nitrogen status; product outturn.

Action of larch bark in the regulation of cortisol induced stress in sheep

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Elisa Asquini

2010-01-01

Full Text Available The effect of Larix decidua (LD dietary administration on gene expression patterns has been evaluated in sheep under ACTH challenge. Experimental protocol was approved by local laws and regulations. Eighteen sheep at maintenance were allotted to 3 groups: CTR (negative control, without ACTH, and supplementation, ACTH (positive control, with ACTH, and without supplementation, LD (ACTH and 50 g/head/day of LD. ACTH was injected for 3 subsequent days to ACTH and LD groups and blood was sampled before (T0 and after 3 (T3 and 51 (T51 hours from the first injection. RNA extracted samples were pooled together within group and time of sampling. A custom oligoarray was synthesized using 24,384 35 -40mer probes designed from 12,194 UniGenes (NCBI on a CombiMatrix 90K platform. Cy5 labelled samples were hybridized on the chip. Statistical analysis, performed with MeV software 4.1 (TIGR, allowed the identification of a set of genes which were up or down regulated as a consequence of ACTH treatment. Genes that resulted differentially expressed were annotated with HomoloGene system and data mining was performed with Babelomics v3.1 tool. Functional analysis showed that most of the differentially expressed genes belong to KEGG pathways involved in immune system response and signaling molecules and interaction. Larch administration was effective in counteracting the effect of ACTH injection on the inflammatory processes, restoring the physiological homeostasis.

Time since death and decay rate constants of Norway spruce and European larch deadwood in subalpine forests determined using dendrochronology and radiocarbon dating

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Petrillo, M.; Cherubini, P.; Fravolini, G.; Ascher, J.; Schärer, M.; Synal, H.-A.; Bertoldi, D.; Camin, F.; Larcher, R.; Egli, M.

2015-09-01

Due to the large size and highly heterogeneous spatial distribution of deadwood, the time scales involved in the coarse woody debris (CWD) decay of Picea abies (L.) Karst. and Larix decidua Mill. in Alpine forests have been poorly investigated and are largely unknown. We investigated the CWD decay dynamics in an Alpine valley in Italy using the five-decay class system commonly employed for forest surveys, based on a macromorphological and visual assessment. For the decay classes 1 to 3, most of the dendrochronological samples were cross-dated to assess the time that had elapsed since tree death, but for decay classes 4 and 5 (poorly preserved tree rings) and some others not having enough tree rings, radiocarbon dating was used. In addition, density, cellulose and lignin data were measured for the dated CWD. The decay rate constants for spruce and larch were estimated on the basis of the density loss using a single negative exponential model. In the decay classes 1 to 3, the ages of the CWD were similar varying between 1 and 54 years for spruce and 3 and 40 years for larch with no significant differences between the classes; classes 1-3 are therefore not indicative for deadwood age. We found, however, distinct tree species-specific differences in decay classes 4 and 5, with larch CWD reaching an average age of 210 years in class 5 and spruce only 77 years. The mean CWD rate constants were 0.012 to 0.018 yr-1 for spruce and 0.005 to 0.012 yr-1 for larch. Cellulose and lignin time trends half-lives (using a multiple-exponential model) could be derived on the basis of the ages of the CWD. The half-lives for cellulose were 21 yr for spruce and 50 yr for larch. The half-life of lignin is considerably higher and may be more than 100 years in larch CWD.

Tree-ring proxies of larch bud moth defoliation: latewood width and blue intensity are more precise than tree-ring width.

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Arbellay, Estelle; Jarvis, Ingrid; Chavardès, Raphaël D; Daniels, Lori D; Stoffel, Markus

2018-05-19

Reconstructions of defoliation by larch bud moth (LBM, Zeiraphera diniana Gn.) based on European larch (Larix decidua Mill.) tree rings have unraveled outbreak patterns over exceptional temporal and spatial scales. In this study, we conducted tree-ring analyses on 105 increment cores of European larch from the Valais Alps, Switzerland. The well-documented history of LBM outbreaks in Valais provided a solid baseline for evaluating the LBM defoliation signal in multiple tree-ring parameters. First, we used tree-ring width measurements along with regional records of LBM outbreaks to reconstruct the occurrence of these events at two sites within the Swiss Alps. Second, we measured earlywood width, latewood width and blue intensity, and compared these parameters with tree-ring width to assess the capacity of each proxy to detect LBM defoliation. A total of six LBM outbreaks were reconstructed for the two sites between AD 1850 and 2000. Growth suppression induced by LBM was, on average, highest in latewood width (59%), followed by total ring width (54%), earlywood width (51%) and blue intensity (26%). We show that latewood width and blue intensity can improve the temporal accuracy of LBM outbreak reconstructions, as both proxies systematically detected LBM defoliation in the first year it occurred, as well as the differentiation between defoliation and non-defoliation years. This study introduces blue intensity as a promising new proxy of insect defoliation and encourages its use in conjunction with latewood width.

Variability of the tree-rings structure of Gmelin’s larch at northern tree line (peninsula of Taymyr

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V. V. Fakhrutdinova

2017-04-01

Full Text Available The study of tree-ring cell structure changes as the result of tree adaptation to varying environmental conditions becomes increasingly important to predict future vegetation shifts under projected climate changes. The estimate of intrapopulation annual variability of wood anatomy characteristics is particularly informative. It helps to divide the contribution of different ecological factors to total features dispersion. In this work, a comparative analysis of individual and climatic variability of tree ring structure characteristics of Gmelin’s larch Larix gmelinii (Rupr. growth within northernmost forest was carried out. The trees from forest-tundra boundary has greater radial growth intensity, forms the bigger conductive zone in rings with wider mean lumen area in comparison with trees from closed forest. This result can be explained by adaptive features and height ecological xylem plasticity of larch. The tree rings structure of larch from boundary with tundra is determined by largely current weather conditions. Is because these ones evince high adaptive plasticity on the level of xylem structure. The xylem reflects joint changes of climate factors and local ecological conditions. The trees from closed forest are characterized by larger individual variability. The local conditions in oldest forest (for example, bad hydrothermal soil conditions inhibit the radial growth and sensitivity to environmental factors. In this case, the trees on individual level are tended to save the normal functioning of water-transport system. The significant differences in ratio individual to climate variability of tree ring structure characteristics can be caused by the different in the level of ecological habitat heterogeneity or the different in the level genetic within-population heterogeneity.

Timing and duration of European larch growing season along altitudinal gradients in the Swiss Alps.

Science.gov (United States)

Moser, Lea; Fonti, Patrick; Büntgen, Ulf; Esper, Jan; Luterbacher, Jürg; Franzen, Julia; Frank, David

2010-02-01

The 2007 European larch (Larix decidua Mill.) growing season was monitored along two elevational transects in the Lötschental valley in the Swiss Alps. Phenological observations and weekly microcore sampling of 28 larch trees were conducted between April and October 2007 at seven study sites regularly spaced from 1350 to 2150 m a.s.l. on northwest- and southeast-facing slopes. The developmental stages of nearly 75,000 individual cells assessed on 1200 thin sections were used to investigate the links between the trees' thermal regimes and growth phases including the beginning and ending of cell enlargement, wall thickening and maturation of the stem wood. Needles appeared approximately 3-4 weeks earlier than stem growth. The duration of ring formation lasted from mid-May to the end of October, with the length of the growing season decreasing along elevation from 137 to 101 days. The onset of the different growing seasons changed by 3-4 days per 100 m elevation; the ending of the growing season, however, appeared minimally related to altitude. If associated with the monitored altitudinal lapse rate of -0.5 degrees C per 100 m, these results translate into a lengthening of the growing season by approximately 7 days per degree Celsius. This study provides new data on the timing and duration of basic growth processes and contributes to quantification of the impacts of global warming on tree growth and productivity.

Climate effects on inter- and intra-annual larch stemwood anomalies in the Mongolian forest-steppe

Science.gov (United States)

Khishigjargal, Mookhor; Dulamsuren, Choimaa; Leuschner, Hanns Hubert; Leuschner, Christoph; Hauck, Markus

2014-02-01

Climate response of tree-ring width and intra-annual wood anomalies were studied in stands of Siberian larch (Larix sibirica) on Mt. Bogd Uul in the forest-steppe ecotone of Mongolia. Climate on Mt. Bogd Uul is characterized by an increase of the annual mean temperature by 1.5 K between 1965 and 2007, the lack of a long-term trend for annual precipitation and, with it, an increase in aridity. Tree-ring width increases with increasing June precipitation of the current year (June) and increasing late summer precipitation of the previous year. In >100-year old trees, also a negative correlation of tree-ring width with the July temperature of the year prior to tree-ring formation was found. Decreasing tree-ring width with increasing snowfall in December can be explained with the protection of the frost-sensitive eggs of gypsy moth by snow cover, which is a major herbivore of larch in Mongolia and causes reduction in the annual stem increment. The most significant change in wood anatomy was the decline of wide latewood, which is attributable to the increase of summer days with a mean temperature > 15 °C and drought periods in summer without precipitation. Increasing summer drought is also thought to have caused the repeated occurrence of missing rings since the 1960s, which were not observed in the late 19th and early 20th centuries.

Warm season precipitation signal in δ2 H values of wood lignin methoxyl groups from high elevation larch trees in Switzerland.

Science.gov (United States)

Riechelmann, Dana F C; Greule, Markus; Siegwolf, Rolf T W; Anhäuser, Tobias; Esper, Jan; Keppler, Frank

2017-10-15

In this study, we tested stable hydrogen isotope ratios of wood lignin methoxyl groups (δ 2 H methoxyl values) as a palaeoclimate proxy in dendrochronology. This is a quite new method in the field of dendrochronology and the sample preparation is much simpler than the methods used before to measure δ 2 H values from wood. We measured δ 2 H methoxyl values in high elevation larch trees (Larix decidua Mill.) from Simplon Valley (southern Switzerland). Thirty-seven larch trees were sampled and five individuals analysed for their δ 2 H methoxyl values at annual (1971-2009) and pentadal resolution (1746-2009). The δ 2 H methoxyl values were measured as CH 3 I released upon treatment of the dried wood samples with hydroiodic acid. 10-90 μL from the head-space were injected into the gas chromatography/high-temperature conversion/isotope ratio mass spectrometry (GC/HTC-IRMS) system. Testing the climate response of the δ 2 H methoxyl values, the annually resolved series show a positive correlation of r = 0.60 with June/July precipitation. The pentadally resolved δ 2 H methoxyl series do not show any significant correlation to climate parameters. Increased precipitation during June and July, which are on average warm and relatively dry months, results in higher δ 2 H values of the xylem water and, therefore, higher δ 2 H values in the lignin methoxyl groups. Therefore, we suggest that δ 2 H methoxyl values of high elevation larch trees might serve as a summer precipitation proxy. Copyright © 2017 John Wiley & Sons, Ltd.

European larch phenology in the Alps: can we grasp the role of ecological factors by combining field observations and inverse modelling?

Science.gov (United States)

Migliavacca, M.; Cremonese, E.; Colombo, R.; Busetto, L.; Galvagno, M.; Ganis, L.; Meroni, M.; Pari, E.; Rossini, M.; Siniscalco, C.; Morra di Cella, U.

2008-09-01

Vegetation phenology is strongly influenced by climatic factors. Climate changes may cause phenological variations, especially in the Alps which are considered to be extremely vulnerable to global warming. The main goal of our study is to analyze European larch ( Larix decidua Mill.) phenology in alpine environments and the role of the ecological factors involved, using an integrated approach based on accurate field observations and modelling techniques. We present 2 years of field-collected larch phenological data, obtained following a specifically designed observation protocol. We observed that both spring and autumn larch phenology is strongly influenced by altitude. We propose an approach for the optimization of a spring warming model (SW) and the growing season index model (GSI) consisting of a model inversion technique, based on simulated look-up tables (LUTs), that provides robust parameter estimates. The optimized models showed excellent agreement between modelled and observed data: the SW model predicts the beginning of the growing season (BGS) with a mean RMSE of 4 days, while GSI gives a prediction of the growing season length (LGS) with a RMSE of 5 days. Moreover, we showed that the original GSI parameters led to consistent errors, while the optimized ones significantly increased model accuracy. Finally, we used GSI to investigate interactions of ecological factors during springtime development and autumn senescence. We found that temperature is the most effective factor during spring recovery while photoperiod plays an important role during autumn senescence: photoperiod shows a contrasting effect with altitude decreasing its influence with increasing altitude.

Tree Line Structure and Dynamics at the Northern Limit of the Larch Forest: Anabar Plateau, Siberia, Russia

Science.gov (United States)

Kharuk, Viacheslav I.; Ranson, Kenneth J.; Im, Sergey T.; Oskorbin, Pavel A.; Dvinskaya, Maria L.; Ovchinnikov, Dmitriy V.

2013-01-01

The goal of the study was to provide an analysis of climate impact before, during, and after the Little Ice Age (LIA) on the larch (Larix gmelinii) tree line at the northern extreme of Siberian forests. Recent decadal climate change impacts on the tree line, regeneration abundance, and age structure were analyzed. The location of the study area was within the forest-tundra ecotone (elevation range 170-450 m) in the Anabar Plateau, northern Siberia. Field studies were conducted along elevational transects. Tree natality/mortality and radial increment were determined based on dendrochronology analyses. Tree morphology, number of living and subfossil trees, regeneration abundance, and age structure were studied. Locations of pre-LIA, LIA, and post-LIA tree lines and refugia boundaries were established. Long-term climate variables and drought index were included in the analysis. It was found that tree mortality from the 16th century through the beginning of the 19th century caused a downward tree line recession. Sparse larch stands experienced deforestation, transforming into tundra with isolated relict trees. The maximum tree mortality and radial growth decrease were observed to have occurred at the beginning of 18th century. Now larch, at its northern boundary in Siberia, is migrating into tundra areas. Upward tree migration was induced by warming in the middle of the 19th century. Refugia played an important role in repopulation of the forest-tundra ecotone by providing a seed source and shelter for recruitment of larch regeneration. Currently this ecotone is being repopulated mainly by tree cohorts that were established after the 1930s. The last two decades of warming did not result in an acceleration of regeneration recruitment because of increased drought conditions. The regeneration line reached (but did not exceed) the pre-LIA tree line location, although contemporary tree heights and stand densities are comparatively lower than in the pre-LIA period. The mean

Variability and ecology of Siberian larch species

Energy Technology Data Exchange (ETDEWEB)

Abaimov, A.P.; Milyutin, L.I. [Russian Academy of Sciences, Krasnoyarsk (Russian Federation). Sukachev Inst. of Forest, Siberian Branch; Lesinski, J.A.; Martinsson, Owe [Swedish Univ. of Agricultural Sciences, Umeaa (Sweden). Dept. of Silviculture

1998-12-31

There are at least four larch taxons distinguished in Siberia that occupy almost 37 percent of the the Russian forests. The natural distribution of the taxons is clinal from the west to the east with L. sibirica Ledeb. in the west followed by L. x czekanowskii Szafer, L. gmelinii Rupr. and L. cajanderi Mayr. L. sibirica and L. x czekanowskii are phytocenosis builders only at the northern timberline and in the South-Siberian mountains whereas L. gmelinii and L. cajanderi are the main species over the vast territory within and beyond the permafrost zone of East Siberia. Due to large variety of growing conditions, the main features of the larch forests in terms of age structure and growth rates are also enormously variable. Thanks to specific life strategies with respect to seed dispersion patterns and very high adaptability to fires that often affect Siberian forests, these larch species regenerate very well being only seldom temporary replaced by Betula sp. forming secondary forest associations. Larch forests of different categories (protective and commercial) are exploited and regenerated in the same way as it is applied for Scots pine in Siberia. There is a growing interest in Siberian larch species among researchers and practitioners from abroad, mainly due to their fast growth and excellent wood properties. Some attempts of introducing Siberian larch species as commercial plantations have already been initiated in western countries. However, the knowledge of botanical, ecological and silvicultural features of Siberian larch species is rather poor outside of Russia. Because of its economic importance for Russian forestry the Siberian larch species have been comprehensively studied for many years and many papers as well as a number of monographs have been published, most of them in Russian. The large Russian expertise concerning regionalisation of seed sources, seed crop and quality, seed orchards, seedling production in nurseries and silvicultural practices in

Strategy for larch breeding in Iceland

Energy Technology Data Exchange (ETDEWEB)

Eysteinsson, T. [Iceland Forest Service, Egilsstadir (Iceland)

1995-12-31

An accelerated breeding program for Siberian larch was initiated in Iceland in 1992. Siberian larch is an important exotic species, but not fully adapted to Icelandic conditions. Selections are made based on adaptive traits such as growth rhythm and resistance to damage as well as form and growth rate. Seed will be produced in containerised, greenhouse orchards, necessitating selection for fecundity to best use expensive greenhouse space. Research will concentrate on developing flower induction treatments for Siberian larch and ways to maximize seed production and viability. 19 refs

Strategy for larch breeding in Iceland

Energy Technology Data Exchange (ETDEWEB)

Eysteinsson, T [Iceland Forest Service, Egilsstadir (Iceland)

1996-12-31

An accelerated breeding program for Siberian larch was initiated in Iceland in 1992. Siberian larch is an important exotic species, but not fully adapted to Icelandic conditions. Selections are made based on adaptive traits such as growth rhythm and resistance to damage as well as form and growth rate. Seed will be produced in containerised, greenhouse orchards, necessitating selection for fecundity to best use expensive greenhouse space. Research will concentrate on developing flower induction treatments for Siberian larch and ways to maximize seed production and viability. 19 refs

Larch: An Analysis Package for XAFS and Related Spectroscopies

International Nuclear Information System (INIS)

Newville, Matthew

2013-01-01

LARCH, a package of analysis tools for XAFS and related spectroscopies is presented. A complete rewrite of the ifeffit package, the initial release of larch preserves the core XAFS analysis procedures such as normalization, background subtraction, Fourier transforms, fitting of XANES spectra, and fitting of experimental spectra to a sum of feff Paths, with few algorithmic changes made in comparison to IFEFFIT. LARCH is written using Python and its packages for scientific programming, which gives significant improvements over IFEFFIT in the ability to handle multi-dimensional and large data sets, write complex analysis scripts, visualize data, add new functionality, and customize existing capabilities. Like the earlier version, larch can run from an interactive command line or in batch-mode, but larch can also be run as a server and accessed from clients using standard inter-process communication techniques available in a variety of computer languages. larch is freely available under an open source license. Examples of using larch are shown, future directions for development are discussed, and collaborations for adding new capabilities are actively sought.

Quantifying ozone uptake at the canopy level of spruce, pine and larch trees at the alpine timberline: an approach based on sap flow measurement

International Nuclear Information System (INIS)

Wieser, G.; Matyssek, R.; Koestner, B.; Oberhuber, W.

2003-01-01

Sap-flow based measurements can be used to estimate ozone uptake at whole-tree and stand levels. - Micro-climatic and ambient ozone data were combined with measurements of sap flow through tree trunks in order to estimate whole-tree ozone uptake of adult Norway spruce (Picea abies), cembran pine (Pinus cembra), and European larch (Larix decidua) trees. Sap flow was monitored by means of the heat balance approach in two trees of each species during the growing season of 1998. In trees making up the stand canopy, the ozone uptake by evergreen foliages was significantly higher than by deciduous ones, when scaled to the ground area. However, if expressed per unit of whole-tree foliage area, ozone flux through the stomata into the needle mesophyll was 1.09, 1.18 and 1.40 nmol m -2 s -1 in Picea abies, Pinus cembra and Larix decidua, respectively. These fluxes are consistent with findings from measurements of needle gas exchange, published from the same species at the study site. It is concluded that the sap flow-based approach offers an inexpensive, spatially and temporally integrating way for estimating ozone uptake at the whole-tree and stand level, intrinsically covering the effect of boundary layers on ozone flux

Relationships between root respiration rate and root morphology, chemistry and anatomy in Larix gmelinii and Fraxinus mandshurica.

Science.gov (United States)

Jia, Shuxia; McLaughlin, Neil B; Gu, Jiacun; Li, Xingpeng; Wang, Zhengquan

2013-06-01

Tree roots are highly heterogeneous in form and function. Previous studies revealed that fine root respiration was related to root morphology, tissue nitrogen (N) concentration and temperature, and varied with both soil depth and season. The underlying mechanisms governing the relationship between root respiration and root morphology, chemistry and anatomy along the root branch order have not been addressed. Here, we examined these relationships of the first- to fifth-order roots for near surface roots (0-10 cm) of 22-year-old larch (Larix gmelinii L.) and ash (Fraxinus mandshurica L.) plantations. Root respiration rate at 18 °C was measured by gas phase O2 electrodes across the first five branching order roots (the distal roots numbered as first order) at three times of the year. Root parameters of root diameter, specific root length (SRL), tissue N concentration, total non-structural carbohydrates (starch and soluble sugar) concentration (TNC), cortical thickness and stele diameter were also measured concurrently. With increasing root order, root diameter, TNC and the ratio of root TNC to tissue N concentration increased, while the SRL, tissue N concentration and cortical proportion decreased. Root respiration rate also monotonically decreased with increasing root order in both species. Cortical tissue (including exodermis, cortical parenchyma and endodermis) was present in the first three order roots, and cross sections of the cortex for the first-order root accounted for 68% (larch) and 86% (ash) of the total cross section of the root. Root respiration was closely related to root traits such as diameter, SRL, tissue N concentration, root TNC : tissue N ratio and stele-to-root diameter proportion among the first five orders, which explained up to 81-94% of variation in the rate of root respiration for larch and up to 83-93% for ash. These results suggest that the systematic variations of root respiration rate within tree fine root system are possibly due to the

[Seasonal variation of soil heat conduction in a larch plantation and its relations to environmental factors].

Science.gov (United States)

Wang, Wen-Jie; Cui, Song; Liu, Wei; Zu, Yuan-Gang; Sun, Wei; Wang, Hui-Min

2008-10-01

Based on a 3-year (2003-2005) observation of soil heat flux (SHF) in a larch (Larix gmelinii) plantation, the characteristics of soil heat conduction in the plantation and their relationships with environment factors were analyzed. The results showed that there was an obvious seasonal variation of SHF in different years and sampling sites. The SHF was positive from April to August and mostly negative from September to next March, with an almost balance between heat income and outcome at annual scale. Solar net radiation had significant effects on the SHF and soil heat conductance (k), and an obvious time-lag effect was found, with 4-5 hours' time-lag in winter and 2-3 hours' time-lag in summer. Based on the real-time measurement of SHF and soil temperature difference at the study sites, the k value was significantly higher in early spring (P 0.05). Therefore, when we use the observation data of soil temperature from weather stations to estimate soil heat flux, the k value in spring (from March to May) could induce a bias estimation.

Contribution to the improvement of seed extraction in larch

Energy Technology Data Exchange (ETDEWEB)

Philippe, G. [Cemagref - Forest nurseries and Plant genetics division, Nogent-sur-Vernisson (France)

1995-12-31

Industrial techniques in a seed plant resulted in the extraction of a small percentage of seed potential (18% in hybrid larch and 40% in European larch). It was determined that the seeds remaining within the cones were as viable as the seeds extracted. Thus, the quantity of marketable seeds was directly proportional to the quantity of seeds extracted and an important gain in seed yield could be achieved by improving extraction techniques. Among the five techniques tested in a second experiment, the two cone grinding treatments, done in a hammer mill, were characterized by the best extraction rate (up to 80% of seed potential) but they resulted in a decrease in seed viability. However, cone grinding applied to large volume of cones produced highly viable seeds. The difference was attributed to the number of cones treated. With regard to other techniques, cone drying followed by cone threshing was more efficient when it was applied to cones previously cut in two or let outside for a couple of months. All these techniques gave better results when cones were collected in spring rather than in autumn whereas cone grinding efficiency did not depend on cone collection date. 8 refs, 1 fig, 2 tabs

Contribution to the improvement of seed extraction in larch

Energy Technology Data Exchange (ETDEWEB)

Philippe, G [Cemagref - Forest nurseries and Plant genetics division, Nogent-sur-Vernisson (France)

1996-12-31

Industrial techniques in a seed plant resulted in the extraction of a small percentage of seed potential (18% in hybrid larch and 40% in European larch). It was determined that the seeds remaining within the cones were as viable as the seeds extracted. Thus, the quantity of marketable seeds was directly proportional to the quantity of seeds extracted and an important gain in seed yield could be achieved by improving extraction techniques. Among the five techniques tested in a second experiment, the two cone grinding treatments, done in a hammer mill, were characterized by the best extraction rate (up to 80% of seed potential) but they resulted in a decrease in seed viability. However, cone grinding applied to large volume of cones produced highly viable seeds. The difference was attributed to the number of cones treated. With regard to other techniques, cone drying followed by cone threshing was more efficient when it was applied to cones previously cut in two or let outside for a couple of months. All these techniques gave better results when cones were collected in spring rather than in autumn whereas cone grinding efficiency did not depend on cone collection date. 8 refs, 1 fig, 2 tabs

Climate signal in d13C of wood lignin methoxyl groups from high-elevation alpine larch trees

Science.gov (United States)

Reichelmann, Dana; Greule, Markus; Treydte, Kerstin; Keppler, Frank; Esper, Jan

2015-04-01

Tree-rings of high alpine larch trees (Larix decidua) were investigated by a recently established method that measures d13C values of the wood lignin methoxyl groups (Greule et al. 2009). The resulting d13C time series were tested for their potential as a climate proxy. For this 37 larch trees were sampled at the tree line near Simplon Village (Southern Switzerland). They were analysed for their tree-ring width (TRW) and from five individuals d13C of the wood lignin methoxyl groups (d13Cmethoxyl) were measured at annual resolution from 1971-2009 and at pentadal resolution from 1747-2009. The d13Cmethoxyl chronologies were corrected for the anthropogenic change in atmospheric CO2 concentration and its decreasing d13C value. Further, the physiological response of the trees to these atmospheric changes was corrected using the flexible correction factor approach of Treydte et al. (2009), which minimise the residuals with the target climate data. This approach results in the highest so far reported correction factors of 0.032 - 0.036‰/ppmv CO2, which are explained by a low water-use efficiency of deciduous larch. The climate response of the new d13Cmethoxyl proxy shows a significant correlation of 0.75 for the annually and 0.87 for the pentadally resolved data with June to August temperatures. TRW shows also significant correlations with June to August temperatures, but they are lower than the correlations observed for the d13Cmethoxyl chronologies. These results indicate the potential of d13Cmethoxyl chronologies as a summer temperature proxy from high-elevation alpine trees with an even stronger signal than reported from earlier published tree-ring width and maximum latewood density temperature reconstructions. References: Greule, M., Mosandl, A., Hamilton, J.T.G., Keppler, F., 2009. A simple rapid method to precisely determine 13C/12C ratios of plant methoxyl groups. Rapid Communications in Mass Spectrometry, 23(11): 1710-1714. Treydte, K.S., Frank, D.C., Saurer, M

Siberian Boreal Forest Aboveground Biomass and Fire Scar Maps, Russia, 1969-2007

Data.gov (United States)

National Aeronautics and Space Administration — This data set provides 30-meter resolution mapped estimates of Cajander larch (Larix cajanderi) aboveground biomass (AGB), circa 2007, and a map of burn perimeters...

Direct seeding of Sitka spruce (Picea sitchensis (Bong.) Carr.), lodgepole pine (Pinus Contorta Dougl. v. contorta) and Siberian larch (Larix sibirica Ledeb.), on scarified seed spots in southern Iceland, using various methods

Energy Technology Data Exchange (ETDEWEB)

Petursson, J.G. [The Icelandic Forestry Association, Reykjavik (Iceland)

1995-12-31

Field experiments were established to study the potential of direct seeding of Sitka spruce, lodgepole pine and Siberian larch in southern Iceland. Five seeding methods were tried; control, covered with gravel, covered with pumice, pyramidal indentations and plastic cone. Spring- and autumn planting of one year old planting stock was also carried out for comparison. The results after two growing seasons are presented. Overall germination was 11,3% the first summer and 19,0% the second summer. Lodgepole pine had significantly highest germination or 41,3%. Sitka spruce, having 26.8% germination, and Siberian larch having 22,6% germination did not differ significantly from each other. The seeding method plastic cone gave the highest germination for all the species used, or 50,3%. Seedling mortality was high after the first winter, except in the plastic cone where more than 80% of the seedlings survived. The number of spots having at least one living seedling after two growth seasons was high in all seeding methods for lodgepole pine or 76,3-95,0% and for Sitka spruce or 71,3-86,3%. This result was however mainly explained by seedlings that germinated in the current growing season. For Siberian larch the number of the spots having one or more living seedlings was low for other seeding methods than plastic cone which gave 68,8%. No difference was found in seedling height between the methods control, covered with gravel, covered with pumice and pyramidal indentations. Survival of planted seedlings differed between planting times. Spring planting (28/6) was found more advantageous for Sitka spruce and lodgepole pine, but autumn planting (3/10) for Siberian larch. When the seeding methods were compared with planting after two growth seasons, it can be concluded that the method plastic cone was the only method tried which was compatible with planting. 45 refs, 9 figs, 14 tabs

Wildfires in northern Siberian larch dominated communities

International Nuclear Information System (INIS)

Kharuk, Viacheslav I; Dvinskaya, Maria L; Im, Sergey T; Ranson, Kenneth J

2011-01-01

The fire history of the northern larch forests within the permafrost zone in a portion of northern Siberia (∼66°N, 100°E) was studied. Since there is little to no human activity in this area, fires within the study area were mostly caused by lightning. Fire return intervals (FRI) were estimated on the basis of burn marks on tree stems and dates of tree natality. FRI values varied from 130 to 350 yr with a 200 ± 50 yr mean. For southerly larch dominated communities, FRI was found to be shorter (77 ± 20 yr at ∼ 61°N, and 82 ± 7 at 64°N), and it was longer at the northern boundary (∼71°) of larch stands (320 ± 50 yr). During the Little Ice Age period in the 16th–18th centuries, FRI was approximately twice as long those as recorded in this study. Fire caused changes in the soil including increases in soil drainage and permafrost thawing depth, and a radial growth increase to about twice the background value (with more than six times observed in extreme cases). This effect may simulate the predicted warming impact on the larch growth in the permafrost zone.

Provenance trials of larch in Siberia

Energy Technology Data Exchange (ETDEWEB)

Milyutin, L.I. [V.N. Sukachev Inst. of Forest SB RAS, Krasnoyarsk (Russian Federation)

1995-12-31

Some results of provenance trials of larch in Siberia are given. These provenance trials were established in the last thirty years by efforts of V.N. Sukaczev Inst. of Forest. Provenances and species of larch were tested in some field trials distributed over Siberia between Lat. N 52 deg and 66 deg, Long. E 88 deg and 113 deg: near Krasnoyarsk, in Republic Khakasia (an altitudes of 800 and 1200 metres), in the Lower Yenisei near Turukhansk, in the west and south regions of Krasnoyarsk territory, in the Upper Lena, near Chita. 2 refs

Provenance trials of larch in Siberia

Energy Technology Data Exchange (ETDEWEB)

Milyutin, L I [V.N. Sukachev Inst. of Forest SB RAS, Krasnoyarsk (Russian Federation)

1996-12-31

Some results of provenance trials of larch in Siberia are given. These provenance trials were established in the last thirty years by efforts of V.N. Sukaczev Inst. of Forest. Provenances and species of larch were tested in some field trials distributed over Siberia between Lat. N 52 deg and 66 deg, Long. E 88 deg and 113 deg: near Krasnoyarsk, in Republic Khakasia (an altitudes of 800 and 1200 metres), in the Lower Yenisei near Turukhansk, in the west and south regions of Krasnoyarsk territory, in the Upper Lena, near Chita. 2 refs

Herbicide Trials on European Larch in Northern Wisconsin

Science.gov (United States)

Daniel A. Netzer

1984-01-01

Herbicides of 17 different rates and formulations were oversprayed on newly planted 1-0 European larch seedlings in teh spring of 1983 at the recommended rates. Simazine, bifenox, oxyfluorfen, promamide, and oryzalin provided adequate weed control with no damage to the larch. Height growth at the end of the first growing season was one-and-a-half times greater in the...

Higher climate warming sensitivity of Siberian larch in small than large forest islands in the fragmented Mongolian forest steppe.

Science.gov (United States)

Khansaritoreh, Elmira; Dulamsuren, Choimaa; Klinge, Michael; Ariunbaatar, Tumurbaatar; Bat-Enerel, Banzragch; Batsaikhan, Ganbaatar; Ganbaatar, Kherlenchimeg; Saindovdon, Davaadorj; Yeruult, Yolk; Tsogtbaatar, Jamsran; Tuya, Daramragchaa; Leuschner, Christoph; Hauck, Markus

2017-09-01

Forest fragmentation has been found to affect biodiversity and ecosystem functioning in multiple ways. We asked whether forest size and isolation in fragmented woodlands influences the climate warming sensitivity of tree growth in the southern boreal forest of the Mongolian Larix sibirica forest steppe, a naturally fragmented woodland embedded in grassland, which is highly affected by warming, drought, and increasing anthropogenic forest destruction in recent time. We examined the influence of stand size and stand isolation on the growth performance of larch in forests of four different size classes located in a woodland-dominated forest-steppe area and small forest patches in a grassland-dominated area. We found increasing climate sensitivity and decreasing first-order autocorrelation of annual stemwood increment with decreasing stand size. Stemwood increment increased with previous year's June and August precipitation in the three smallest forest size classes, but not in the largest forests. In the grassland-dominated area, the tree growth dependence on summer rainfall was highest. Missing ring frequency has strongly increased since the 1970s in small, but not in large forests. In the grassland-dominated area, the increase was much greater than in the forest-dominated landscape. Forest regeneration decreased with decreasing stand size and was scarce or absent in the smallest forests. Our results suggest that the larch trees in small and isolated forest patches are far more susceptible to climate warming than in large continuous forests pointing to a grim future for the forests in this strongly warming region of the boreal forest that is also under high land use pressure. © 2017 John Wiley & Sons Ltd.

Acylated flavonol glycosides from Larix needles

NARCIS (Netherlands)

Niemann, Gerard J.

2006-01-01

Kaempferol-3-p-coumarylglucoside (KCG) was isolated from ether fractions of acetone-extracted freeze-dried needles of all larch species investigated. In each case, KCG was found as one of the main flavonoids, whereas often a variety of closely related, acylated flavonoids was present in either

Assessing the threat posed by indigenous exotics: A case study of two North American bark beetle species

Science.gov (United States)

K. J. Dodds; D. W. Gilmore; S. J. Seybold

2010-01-01

The Douglas-fir beetle, Dendroctonus pseudotsugae Hopkins, was detected in 2001 in northern Minnesota outside its natural range and the range of its native hosts, Douglas-fir, Pseudotsuga menziesii (Mirbel) Franco, and western larch, Larix occidentalis Nutt. Consecutive years of...

Siberian larch at the western edge of its area

Directory of Open Access Journals (Sweden)

Kishchenko Ivan Tarasovich

2015-06-01

In the vertical structure of phytocenoses with Siberian larch up to 4 plant tiers are formed: the 1st and 2nd tier of the forest stand; the 3rd - grassy and shrubby; the 4th - mossy. The last two layers are usually developed very moderately, floristically poor and are noted for strong mosaic. There is no undergrowth. The reliable undergrowth of conifers is completely absent. Resumption of Siberian larch stopped 50-60 years ago.

Dynamics of the larch taiga-permafrost coupled system in Siberia under climate change

Energy Technology Data Exchange (ETDEWEB)

Zhang Ningning [Graduate School of Environmental Studies, Nagoya University, Nagoya, Aichi 464-8601 (Japan); Yasunari, Tetsuzo [Hydrospheric Atmospheric Research Center, Nagoya University, Nagoya 464-8601 (Japan); Ohta, Takeshi, E-mail: zhangningning@lasg.iap.ac.cn [Study Consortium for Earth-Life Interactive Systems (SELIS) of Nagoya University, Nagoya (Japan)

2011-04-15

Larch taiga, also known as Siberian boreal forest, plays an important role in global and regional water-energy-carbon (WEC) cycles and in the climate system. Recent in situ observations have suggested that larch-dominated taiga and permafrost behave as a coupled eco-climate system across a broad boreal zone of Siberia. However, neither field-based observations nor modeling experiments have clarified the synthesized dynamics of this system. Here, using a new dynamic vegetation model coupled with a permafrost model, we reveal the processes of interaction between the taiga and permafrost. The model demonstrates that under the present climate conditions in eastern Siberia, larch trees maintain permafrost by controlling the seasonal thawing of permafrost, which in turn maintains the taiga by providing sufficient water to the larch trees. The experiment without permafrost processes showed that larch would decrease in biomass and be replaced by a dominance of pine and other species that suffer drier hydroclimatic conditions. In the coupled system, fire not only plays a destructive role in the forest, but also, in some cases, preserves larch domination in forests. Climate warming sensitivity experiments show that this coupled system cannot be maintained under warming of about 2 deg. C or more. Under such conditions, a forest with typical boreal tree species (dark conifer and deciduous species) would become dominant, decoupled from the permafrost processes. This study thus suggests that future global warming could drastically alter the larch-dominated taiga-permafrost coupled system in Siberia, with associated changes of WEC processes and feedback to climate.

Dynamics of the larch taiga-permafrost coupled system in Siberia under climate change

International Nuclear Information System (INIS)

Zhang Ningning; Yasunari, Tetsuzo; Ohta, Takeshi

2011-01-01

Larch taiga, also known as Siberian boreal forest, plays an important role in global and regional water-energy-carbon (WEC) cycles and in the climate system. Recent in situ observations have suggested that larch-dominated taiga and permafrost behave as a coupled eco-climate system across a broad boreal zone of Siberia. However, neither field-based observations nor modeling experiments have clarified the synthesized dynamics of this system. Here, using a new dynamic vegetation model coupled with a permafrost model, we reveal the processes of interaction between the taiga and permafrost. The model demonstrates that under the present climate conditions in eastern Siberia, larch trees maintain permafrost by controlling the seasonal thawing of permafrost, which in turn maintains the taiga by providing sufficient water to the larch trees. The experiment without permafrost processes showed that larch would decrease in biomass and be replaced by a dominance of pine and other species that suffer drier hydroclimatic conditions. In the coupled system, fire not only plays a destructive role in the forest, but also, in some cases, preserves larch domination in forests. Climate warming sensitivity experiments show that this coupled system cannot be maintained under warming of about 2 deg. C or more. Under such conditions, a forest with typical boreal tree species (dark conifer and deciduous species) would become dominant, decoupled from the permafrost processes. This study thus suggests that future global warming could drastically alter the larch-dominated taiga-permafrost coupled system in Siberia, with associated changes of WEC processes and feedback to climate.

Intraseasonal carbon sequestration and allocation in larch trees growing on permafrost in Siberia after 13C labeling (two seasons of 2013-2014 observation).

Science.gov (United States)

Masyagina, Oxana; Prokushkin, Anatoly; Kirdyanov, Alexander; Artyukhov, Aleksey; Udalova, Tatiana; Senchenkov, Sergey; Rublev, Aleksey

2016-12-01

This research is an attempt to study seasonal translocation patterns of photoassimilated carbon within trees of one of the high latitudes widespread deciduous conifer species Larix gmelinii (Rupr. Rupr). For this purpose, we applied whole-tree labeling by 13 CO 2 , which is a powerful and effective tool for tracing newly developed assimilates translocation to tissues and organs of a tree. Experimental plot has been established in a mature 105-year-old larch stand located within the continuous permafrost area near Tura settlement (Central Siberia, 64°17'13″N, 100°11'55″E, 148 m a.s.l.). Measurements of seasonal photosynthetic activity and foliage parameters (i.e., leaf length, area, biomass, etc.), and sampling were arranged from early growing season (June 8, 2013; May 14, 2014) until yellowing and senescence of needles (September 17, 2013; September 14, 2014). Labeling by 13 C of the tree branch (June 2013, for 3 branch replicates in 3 different trees) and the whole tree was conducted at early (June 2014), middle (July 2014), and late (August 2013) phase of growing season (for different trees in 3 replicates each time) by three pulses [(CO 2 )max = 3000-4000 ppmv, 13 CO 2 (30 % v/v)]. We found at least two different patterns of carbon translocation associated with larch CO 2 assimilation depending on needle phenology. In early period of growing season (June), 13 C appearing in newly developed needles is a result of remobilized storage material use for growth purposes. Then approximately at the end of June, growth processes is switching to storage processes lasting to the end of growing season.

Sudetic larch in Germany - Results of provenance and progeny research

Energy Technology Data Exchange (ETDEWEB)

Weisgerber, H. [Forest Centre for Management Planning, Research and Ecology, Hann Muenden (Germany)

1995-12-31

There are only a few older sources of Sudetic larch in Germany. They distinguish themselves by outstanding growth and low susceptibility to canker. This impression was confirmed by results of provenance research. The Sudetic larch tested in comparison with numerous other provenances proved to be fast-growing, site-tolerant, to a large extent insusceptible to canker, with straight but also slightly to moderately curved stems. The Sudetic provenances behave remarkably uniformly as regards these characteristics. In addition to provenance research investigations have been going on for a long time in Germany into individual differences within the Sudetic larch populations. A report is given on the results of progeny tests from free and controlled pollination, using the example of a seed orchard consisting of 54 clones. We point also to possibilities for improving stem quality by selection steps. The results of provenance and progeny research on Sudetic larch are in the meantime being put to use to a large extent in practical forestry. The forest administrations of various federal lands recommend the use of reproductive material of Sudetic origin and from seed orchards. 20 refs, 3 figs

Sudetic larch in Germany - Results of provenance and progeny research

Energy Technology Data Exchange (ETDEWEB)

Weisgerber, H [Forest Centre for Management Planning, Research and Ecology, Hann Muenden (Germany)

1996-12-31

There are only a few older sources of Sudetic larch in Germany. They distinguish themselves by outstanding growth and low susceptibility to canker. This impression was confirmed by results of provenance research. The Sudetic larch tested in comparison with numerous other provenances proved to be fast-growing, site-tolerant, to a large extent insusceptible to canker, with straight but also slightly to moderately curved stems. The Sudetic provenances behave remarkably uniformly as regards these characteristics. In addition to provenance research investigations have been going on for a long time in Germany into individual differences within the Sudetic larch populations. A report is given on the results of progeny tests from free and controlled pollination, using the example of a seed orchard consisting of 54 clones. We point also to possibilities for improving stem quality by selection steps. The results of provenance and progeny research on Sudetic larch are in the meantime being put to use to a large extent in practical forestry. The forest administrations of various federal lands recommend the use of reproductive material of Sudetic origin and from seed orchards. 20 refs, 3 figs

Genetic aftereffects of increased temperature in Larix

Science.gov (United States)

Michael S. Greenwood; Keith W. Hutchinson

1996-01-01

We tested the hypothesis that temperature during gametogenesis and embryogenesis can affect progeny genotype and phenotype. Identical crosses were made among cloned parents of Larix spp. inside and outside a greenhouse, where the temperature inside averaged 4?C above the outside temperature. Significant growth differences as a function of crossing...

Modeling species’ realized climatic niche space and predicting their response to global warming for several western forest species with small geographic distributions

Science.gov (United States)

Marcus V. Warwell; Gerald E. Rehfeldt; Nicholas L. Crookston

2010-01-01

The Random Forests multiple regression tree was used to develop an empirically based bioclimatic model of the presence-absence of species occupying small geographic distributions in western North America. The species assessed were subalpine larch (Larix lyallii), smooth Arizona cypress (Cupressus arizonica ssp. glabra...

Transcriptome Analysis of mRNA and miRNA in Somatic Embryos of Larix leptolepis Subjected to Hydrogen Treatment

Directory of Open Access Journals (Sweden)

Yali Liu

2016-11-01

Full Text Available Hydrogen is a therapeutic antioxidant that has been used extensively in clinical trials. It also acts as a bioactive molecule that can alleviate abiotic stress in plants. However, the biological effects of hydrogen in somatic embryos and the underlying molecular basis remain largely unknown. In this study, the morphological and physiological influence of exogenous H2 treatment during somatic embryogenesis was characterized in Larix leptolepis Gordon. The results showed that exposure to hydrogen increased the proportions of active pro-embryogenic cells and normal somatic embryos. We sequenced mRNA and microRNA (miRNA libraries to identify global transcriptome changes at different time points during H2 treatment of larch pro-embryogenic masses (PEMs. A total of 45,393 mRNAs and 315 miRNAs were obtained. Among them, 4253 genes and 96 miRNAs were differentially expressed in the hydrogen-treated libraries compared with the control. Further, a large number of the differentially expressed mRNAs and miRNAs were related to reactive oxygen species (ROS homeostasis and cell cycle regulation. We also identified 4399 potential target genes for 285 of the miRNAs. The differential expression data and the mRNA-miRNA interaction network described here provide new insights into the molecular mechanisms that determine the performance of PEMs exposed to H2 during somatic embryogenesis.

Net ecosystem exchange of carbon dioxide and water of far eastern Siberian Larch (Larix cajanderii on permafrost

Directory of Open Access Journals (Sweden)

A. J. Dolman

2004-01-01

Full Text Available Observations of the net ecosystem exchange of water and CO2 were made during two seasons in 2000 and 2001 above a Larch forest in Far East Siberia (Yakutsk. The measurements were obtained by eddy correlation. There is a very sharply pronounced growing season of 100 days when the forest is leaved. Maximum half hourly uptake rates are 18 µmol m-2 s-1; maximum respiration rates are 5 µmol m-2 s-1. Net annual sequestration of carbon was estimated at 160 gCm-2 in 2001. Applying no correction for low friction velocities added 60 g C m-2. The net carbon exchange of the forest was extremely sensitive to small changes in weather that may switch the forest easily from a sink to a source, even in summer. June was the month with highest uptake in 2001. The average evaporation rate of the forest approached 1.46 mm day-1 during the growing season, with peak values of 3 mm day-1 with an estimated annual evaporation of 213 mm, closely approaching the average annual rainfall amount. 2001 was a drier year than 2000 and this is reflected in lower evaporation rates in 2001 than in 2000. The surface conductance of the forest shows a marked response to increasing atmospheric humidity deficits. This affects the CO2 uptake and evaporation in a different manner, with the CO2 uptake being more affected. There appears to be no change in the relation between surface conductance and net ecosystem uptake normalized by the atmospheric humidity deficit at the monthly time scale. The response to atmospheric humidity deficit is an efficient mechanism to prevent severe water loss during the short intense growing season. The associated cost to the sequestration of carbon may be another explanation for the slow growth of these forests in this environment.

Early and late seasonal carbon sequestration and allocation in larch trees growing on permafrost in Central Siberia

Science.gov (United States)

Masyagina, Oxana; Prokushkin, Anatoly; Kirdyanov, Alexander; Artyukhov, Aleksey; Udalova, Tatiana; Senchenkov, Sergey; Rublev, Aleksey

2014-05-01

Despite large geographic extent of deciduous conifer species Larix gmelinii, its seasonal photosynthetic activity and translocation of photoassimilated carbon within a tree remain poorly studied. To get better insight into productivity of larch trees growing on permafrost soils in Siberian larch biome we aimed to analyze dynamics of foliage parameters (i.e. leaf area, biomass, %N, %P etc.), seasonal dynamics of photosynthetic activity and apply whole tree labeling by 13CO2, which is powerful and effective tool for tracing newly developed assimilates translocation to tissues and organs of a tree (Kagawa et al., 2006; Keel et al., 2012). Experimental plot has been established in mature 105 year-old larch stand located within the continuous permafrost area near Tura settlement (Central Siberia, 64o17'13" N, 100o11'55" E, 148 m a.s.l.). Trees selected for experiments represented mean tree of the stand. Measurements of seasonal photosynthetic activity and foliar biomass sampling were arranged from early growing season (June 8, 2013) until yellowing and senescence of needles on September 17, 2013. Labeling by 13C in whole tree chamber was conducted by three pulses ([CO2]max ≤ 2,500 ppmv, 13CO2 (30% v/v)) at the early (June) and late (August) phase of growing season for different trees in 3 replicates each time. Both early season and late season labeling experiments demonstrated high rate of 13CO2 assimilation and respective enrichment of needle tissues by 13C: δ13C increased from -28.7 up to +670‰ just after labeling. However, there was distinct post-labeling dynamics of needle δ13C among two seasonal experiments. At the early season 13C depletion in labeled needles was slower, and δ13C approached after 40 days ca. +110 ‰ and remained constant till senescence. In the late season (August) needles were losing labeled C with much faster rate and approached only +1.5 ‰ upon senescence (28 days exposition). These findings suggest that in early season ca. 20% of

Separating rhizosphere respiration from total soil respiration in two larch plantations in northeastern China.

Science.gov (United States)

Jiang, Lifen; Shi, Fuchen; Li, Bo; Luo, Yiqi; Chen, Jiquan; Chen, Jiakuan

2005-09-01

The potential capacity of soil to sequester carbon in response to global warming is strongly regulated by the ratio of rhizosphere respiration to respiration by soil microbial decomposers, because of their different temperature sensitivities. To quantify relative contributions of rhizosphere respiration to total soil respiration as influenced by forest stand development, we conducted a trenching study in two larch (Larix gmelini (Rupr.) Rupr.) plantations, aged 17 and 31 years, in northeastern China. Four plots in each plantation were randomly selected and trenched in early May 2001. Soil surface CO2 effluxes both inside and outside the plots were measured from May 2001 to August 2002. Soil respiration (i.e., the CO2 effluxes outside the trenched plots) varied similarly in the two plantations from 0.8 micromol m(-2) s(-1) in winter to 6.0 micromol m(-2) s(-1) in summer. Rhizosphere respiration (i.e., CO2 efflux outside the trenched plots minus that inside the plots) varied from 0.2 to 2.0 micromol m(-2) s(-1) in the old forest and from 0.3 to 4.0 micromol m(-2) s(-1) in the young forest over the seasons. Rhizosphere respiration, on average, accounted for 25% of soil respiration in the old forest and 65% in the young forest. Rhizosphere and soil respiration were significantly correlated with soil temperature but not with soil water content. We conclude that the role forests play in regulating climate change may depend on their age.

Tree-ring growth patterns and climatic signals along a vertical transect of larch sites in the Simplon and Rhône Valleys (Switzerland)

Science.gov (United States)

Riechelmann, Dana F. C.; Esper, Jan

2017-04-01

State-of-the-art millennial long temperature reconstructions from the European Alps integrate wood samples of Larix decidua Mill. from the Lötschental and Simplon regions in Switzerland (Büntgen et al., 2005; 2006). Some of the oldest samples that enable the extension of the time-series back into the first millennium AD are obtained from old buildings in Simplon Village, through the precise location of these samples and the elevation of sampling sites remain unknown. We here evaluate the growth characteristics of larch tree-ring width data along a vertical transect in the Simplon and Rhône valleys. 330 trees from nine sites in 985, 1100, 1400, 1575, 1710, 1712, 1900, 2020, and 2150 m asl have been sampled and analysed for their climate signals. The results indicate a stronger temperature signal in the tree-ring width with increasing elevation. The lower the sites the more a drought signal is imprinted in the ring width data. The intermediate site at 1400 m asl does not show any pronounced climate signal. A comparison of growth patterns of living-tree sites with samples from the historical buildings in Simplon Village (Riechelmann et al., 2013) indicates the construction timber to origin from intermediate to higher elevations. We therefore do not expect strong temperature signal from these timbers. References: Büntgen, U., Esper, J., Frank, D.C., Nicolussi, K., Schmidhalter, M., 2005. A 1052-year tree-ring proxy for Alpine summer temperatures. Climate Dynamics 25: 141-153. Büntgen, U., Frank, D.C., Nievergelt, D., Esper J., 2006. Summer temperature variations in the European Alps, A.D. 755-2004. Journal of Climate 19: 5606-5623. Riechelmann, D.F.C., Schmidhalter, M., Büntgen, U., Esper, J., 2013. Extending a high-elevation larch ring width chronology from the Simplon region in the Swiss Alps over the past millenium. TRACE 11:103-108.

Longevity of active Phytophthora ramorum in terminal tree hosts following the removal of primary sporulating hosts

Science.gov (United States)

Barnaby Wylder; Mick Biddle; Anna Harris; Joan Webber

2017-01-01

The Forestry Commission-managed forest estate located in Plym, Devon (southwest England) was one of the first locations in late summer 2009 to have stands of Larix kaempferi (Japanese larch) confirmed as infected with Phytophthora ramorum (EU1 lineage). The 398 ha forest had a high proportion (>30%) of

Determining modulus of elasticity of ancient structural timber

Science.gov (United States)

Houjiang Zhang; Lei Zhu; Yanliang Sun; Xiping Wang; Haicheng Yan

2011-01-01

During maintenance of ancient timber architectures, it is important to determine mechanical properties of the wood component materials non-destructively and effectively, so that degraded members may be replaced or repaired to avoid structural failure. Experimental materials are four larch (Larix principis-rupprechtii Mayr.) components, which were taken down from the...

Changes in tracheid and ray traits in fire scars of North American conifers and their ecophysiological implications

Science.gov (United States)

Estelle Arbellay; Markus Stoffel; Elaine K. Sutherland; Kevin T. Smith; Donald A. Falk

2014-01-01

Fire scars have been widely used as proxies for the reconstruction of fire history; however, little is known about the impact of fire injury on wood anatomy. This study investigates changes in tracheid and ray traits in fire scars of Douglas fir (Pseudotsuga menziesii), western larch (Larix occidentalis) and ponderosa pine (

CO2 and water vapor exchange of a larch forest in northern Japan

International Nuclear Information System (INIS)

Hirano, Takashi; Hirata, Ryuichi; Harazono, Yoshinobu

2003-01-01

In the northern part of East Asia, forests dominated by larch are extensively distributed and probably play an important role in the global carbon cycle. However, a knowledge of the CO 2 balance of larch forests based on long-term flux measurements is very restricted in East Asia. Thus, a long-term flux measurement has been started in 2000 at a larch plantation on a flat terrain in Hokkaido, Japan to obtain more information on the CO 2 and energy balances of larch forests. From September 2000 to August 2001 the net ecosystem CO 2 exchange (NEE) changed seasonally in accordance with the annual cycles of phenology and climate. NEE was negative for six months of the growing season, May-September; the larch ecosystem was a carbon sink with a peak intensity of -0.38 mol m 2 d1 for this period. In the leafless season from November to April the forest ecosystem was a carbon source with an intensity ranging between 0 and 0.05 mol/m 2 /d. Annual NEE from September 2000 to August 2001 was 24.4 to 32.4 mol m 2 /yr (= 293 to 389 gC/m 2 /yr); this value is compatible with those reported from other temperate forests. Annual evapotranspiration for the same period was 367 mm, which was only 29% of annual precipitation

Bedrock type significantly affects individual tree mortality for various conifers in the inland Northwest, U.S.A

Science.gov (United States)

James A. Moore; David A Hamilton; Yu Xiao; John Byrne

2004-01-01

Individual tree mortality models for western white pine (Pinus monticola Dougl. ex D. Don), Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), grand fir (Abies grandis (Dougl. ex D. Don) Lindl.), western redcedar (Thuja plicata Donn ex. D. Don), western hemlock (Tsuga heterophylla (Raf.) Sarg.), and western larch (Larix occidentalis Nutt.) were developed using data...

Growth dynamics variation of different larch provenances under the mountain conditions in Poland

Energy Technology Data Exchange (ETDEWEB)

Kulej, M. [Univ. of Agriculture, Cracow (Poland). Section of Seed Production and Selection

1995-12-31

The results of 25-year investigations based on measurements and statistical analysis concerning the growth dynamics variation of larch provenances from the entire area of Poland are reported in this paper. This is the first larch provenance experiment in Poland under mountain conditions. The results obtained showed a significant variability among the provenances tested as regards the basic growth characters (height, d.b.h., growth index) at the age of 5, 8, 11, 15, 20 and 25 years. The larch from Klodzko and Proszkow turned out to be the best in respect of growth during the entire 25-years period. Decidedly bad were provenances from Marcule, Grojec, Rawa mazowiecka and Kroscienko. We cannot forecast the future growth of larch when trees are 5-years old since such prognosis may carry an error. However, on the basis of the results obtained it may be concluded that when trees are about 8 years old the stabilization of the position of individual provenances as regards growth takes place. The height growth curves for the individual provenances during the 25-years period (with exception of the provenance from Marcule) fall within the interval {+-} 0,5S from the compensated curve for the entire population studied. All larch provenances in the experiment had reached the height growth culmination. A greatest differentiation in respect of this character occurred in case of the provenances from Sudetes. 27 refs, 4 figs, 8 tabs

Growth dynamics variation of different larch provenances under the mountain conditions in Poland

Energy Technology Data Exchange (ETDEWEB)

Kulej, M [Univ. of Agriculture, Cracow (Poland). Section of Seed Production and Selection

1996-12-31

The results of 25-year investigations based on measurements and statistical analysis concerning the growth dynamics variation of larch provenances from the entire area of Poland are reported in this paper. This is the first larch provenance experiment in Poland under mountain conditions. The results obtained showed a significant variability among the provenances tested as regards the basic growth characters (height, d.b.h., growth index) at the age of 5, 8, 11, 15, 20 and 25 years. The larch from Klodzko and Proszkow turned out to be the best in respect of growth during the entire 25-years period. Decidedly bad were provenances from Marcule, Grojec, Rawa mazowiecka and Kroscienko. We cannot forecast the future growth of larch when trees are 5-years old since such prognosis may carry an error. However, on the basis of the results obtained it may be concluded that when trees are about 8 years old the stabilization of the position of individual provenances as regards growth takes place. The height growth curves for the individual provenances during the 25-years period (with exception of the provenance from Marcule) fall within the interval {+-} 0,5S from the compensated curve for the entire population studied. All larch provenances in the experiment had reached the height growth culmination. A greatest differentiation in respect of this character occurred in case of the provenances from Sudetes. 27 refs, 4 figs, 8 tabs

Synthesis of nickel-incorporated larch-based carbon membranes with controllable porous structure for gas separation

Energy Technology Data Exchange (ETDEWEB)

Zhao, Xin; Li, Wei; Huang, Zhanhua; Liu, Shouxin, E-mail: chemist@126.com, E-mail: liushouxin@126.com [Northeast Forestry University, College of Material Science and Engineering (China)

2015-11-15

Ni-incorporated larch-based carbon membranes have been synthesized by introducing the Ni(NO{sub 3}){sub 2} into the liquefied larch using liquefied larch sawdust as precursors and F127 as the soft template. The porous structure can be tailored by the amount of Ni(NO{sub 3}){sub 2}, and the Ni and NiO nanoparticles with a size of 10 nm incorporated in the carbon frameworks. The increase in Ni(NO{sub 3}){sub 2} content can lead to the formation of disordered porous structure and shrinkage of carbon frameworks. The Ni-incorporated carbon membranes with largest pores possess highest gas permeation for N{sub 2}, CO{sub 2}, and O{sub 2} of 37.5, 19.8, and 55.5 m{sup 3} cm/m{sup 2} h kPa, which is larger than that of the pure carbon membranes, respectively. However, the poor ordered porous structure caused by adding large amount of Ni(NO{sub 3}){sub 2} can reduce the gas separation performance, which is attributed to the weaken of the molecular sieve function. The results indicate that the incorporation of few nanoparticles into larch-based carbon membranes can improve molecular sieve function.Graphical abstractNi-incorporated larch-based carbon membranes have been synthesized by introducing the Ni(NO{sub 3}){sub 2} into the liquefied larch. The porous structure can be tailored by the amount of Ni(NO{sub 3}){sub 2}, and the Ni and NiO nanoparticles incorporated in the carbon frameworks. The Ni-incorporated carbon membranes with largest pores possess highest gas permeation and gas permseparation.

Genes Sufficient for Synthesizing Peptidoglycan are Retained in Gymnosperm Genomes, and MurE from Larix gmelinii can Rescue the Albino Phenotype of Arabidopsis MurE Mutation.

Science.gov (United States)

Lin, Xiaofei; Li, Ningning; Kudo, Hiromi; Zhang, Zhe; Li, Jinyu; Wang, Li; Zhang, Wenbo; Takechi, Katsuaki; Takano, Hiroyoshi

2017-03-01

The endosymbiotic theory states that plastids are derived from a single cyanobacterial ancestor that possessed a cell wall. Peptidoglycan (PG), the main component of the bacteria cell wall, gradually degraded during plastid evolution. PG-synthesizing Mur genes have been found to be retained in the genomes of basal streptophyte plants, although many of them have been lost from the genomes of angiosperms. The enzyme encoded by bacterial MurE genes catalyzes the formation of the UDP-N-acetylmuramic acid (UDP-MurNAc) tripeptide in bacterial PG biosynthesis. Knockout of the MurE gene in the moss Physcomitrella patens resulted in defects of chloroplast division, whereas T-DNA-tagged mutants of Arabidopsis thaliana for MurE revealed inhibition of chloroplast development but not of plastid division, suggesting that AtMurE is functionally divergent from the bacterial and moss MurE proteins. Here, we could identify 10 homologs of bacterial Mur genes, including MurE, in the recently sequenced genomes of Picea abies and Pinus taeda, suggesting the retention of the plastid PG system in gymnosperms. To investigate the function of gymnosperm MurE, we isolated an ortholog of MurE from the larch, Larix gmelinii (LgMurE) and confirmed its presence as a single copy per genome, as well as its abundant expression in the leaves of larch seedlings. Analysis with a fusion protein combining green fluorescent protein and LgMurE suggested that it localizes in chloroplasts. Cross-species complementation assay with MurE mutants of A. thaliana and P. patens showed that the expression of LgMurE cDNA completely rescued the albefaction defects in A. thaliana but did not rescue the macrochloroplast phenotype in P. patens. The evolution of plastid PG and the mechanism behind the functional divergence of MurE genes are discussed in the context of information about plant genomes at different evolutionary stages. © The Author 2017. Published by Oxford University Press on behalf of Japanese Society of

Net ecosystem CO2 exchange over a larch forest in Hokkaido, Japan

International Nuclear Information System (INIS)

Huimin Wang; Saigusa, Nobuko; Yamamoto, Susumu; Kondo, Hiroaki; Hirano, Takashi; Toriyama, Atsushi; Fujinuma, Yasumi

2004-01-01

Larch forests are distributed extensively in the east Eurasian continent and are expected to play a significant role in the terrestrial ecosystem carbon cycling process. In view of the fact that studies on carbon exchange for this important biome have been very limited, we have initiated a long-term flux observation in a larch forest ecosystem in Hokkaido in northern Japan since 2000. The net ecosystem CO 2 exchange (NEE) showed large seasonal and diurnal variation. Generally, the larch forest ecosystem released CO 2 in nighttime and assimilated CO 2 in daytime during the growing season from May to October. The ecosystem started to become a net carbon sink in May, reaching a maximum carbon uptake as high as 186 g C m -2 month -1 in June. With the yellowing, senescing and leaf fall, the ecosystem turned into a carbon source in November. During the non-growing season, the larch forest ecosystem became a net source of CO 2 , releasing an average of 16.7 g C m -2 month -1 . Overall, the ecosystem sequestered 141-240 g C m -2 yr -1 in 2001. The NEE was significantly influenced by environmental factors. Respiration of the ecosystem, for example, was exponentially dependent on air temperature, while photosynthesis was related to the incident PAR in a manner consistent with the Michaelis-Menten model. Although the vapor pressure deficit (VPD) was scarcely higher than 15 hPa, the CO 2 uptake rate was also depressed when VPD surpassed 10 hPa (Author)

Synthesis of nickel-incorporated larch-based carbon membranes with controllable porous structure for gas separation

Science.gov (United States)

Zhao, Xin; Li, Wei; Huang, Zhanhua; Liu, Shouxin

2015-11-01

Ni-incorporated larch-based carbon membranes have been synthesized by introducing the Ni(NO3)2 into the liquefied larch using liquefied larch sawdust as precursors and F127 as the soft template. The porous structure can be tailored by the amount of Ni(NO3)2, and the Ni and NiO nanoparticles with a size of 10 nm incorporated in the carbon frameworks. The increase in Ni(NO3)2 content can lead to the formation of disordered porous structure and shrinkage of carbon frameworks. The Ni-incorporated carbon membranes with largest pores possess highest gas permeation for N2, CO2, and O2 of 37.5, 19.8, and 55.5 m3 cm/m2 h kPa, which is larger than that of the pure carbon membranes, respectively. However, the poor ordered porous structure caused by adding large amount of Ni(NO3)2 can reduce the gas separation performance, which is attributed to the weaken of the molecular sieve function. The results indicate that the incorporation of few nanoparticles into larch-based carbon membranes can improve molecular sieve function.

Variability in understory evapotranspiration with overstory density in Siberian larch forests

Science.gov (United States)

Tobio, A.; Loranty, M. M.; Kropp, H.; Pena, H., III; Alexander, H. D.; Natali, S.; Kholodov, A. L.

2016-12-01

Arctic ecosystems are changing rapidly in response to amplified rates of climate change. Increased vegetation productivity, altered ecosystem carbon and hydrologic cycling, and increased wildfire severity are among the key responses to changing permafrost and climate conditions. Boreal larch forests in northeastern Siberia are a critical but understudied ecosystem affected by these modifications. Understory vegetation in these ecosystems, which typically have low canopy cover, may account for half of all water fluxes. Despite the potential importance of the understory for ecosystem water exchange, there has been relatively little research examining variability in understory evapotranspiration in boreal larch forests. In particular, the water balance of understory shrubs and mosses is largely undefined and could provide insight on how understory vegetation and our changing climate interact. This is especially important because both observed increases in vegetation productivity and wildfire severity could lead to increases in forests density, altering the proportional contributions of over- and understory vegetation to whole ecosystem evapotranspiration. In order to better understand variability in understory evapotranspiration we measured in larch forests with differing overstory density and permafrost conditions that likely vary as a consequence of fire severity. We used the static chamber technique to measure fluxes across a range of understory vegetation types and environmental conditions. In general, we found that the understory vegetation in low density stands transpires more than that in high density stands. This tends to be correlated with a larger amount of aboveground biomass in the low density stands, and an increase in solar radiation, due to less shading by overstory trees. These results will help us to better understand water balances, evapotranspiration variability, and productivity changes associated with climate on understory vegetation. Additionally

[Aboveground biomass and nutrient distribution patterns of larch plantation in a montane region of eastern Liaoning Province, China].

Science.gov (United States)

Yan, Tao; Zhu, Jiao-Jun; Yang, Kai; Yu, Li-Zhong

2014-10-01

Larch is the main timber species of forest plantations in North China. Imbalance in nutrient cycling in soil emerged due to single species composition and mono system structure of plantation. Thus it is necessary to grasp its biomass and nutrients allocation for scientific management and nutrient cycling studies of larch plantation. We measured aboveground biomass (stem, branch, bark and leaf) and nutrient concentrations (C, N, P, K, Ca, Mg, Fe, Mn, Cu and Zn), and analyzed the patterns of accumulation and distribution of 19-year-old larch plantation with diameter at breast height of 12. 8 cm, tree height of 15. 3 m, and density of 2308 trees · hm(-2), in a montane region of eastern Liaoning Province, China. The results showed that aboveground biomass values were 70.26 kg and 162.16 t · hm(-2) for the individual tree of larch and the stand, respectively. There was a significant difference between biomass of the organs, and decreased in the order of stem > branch > bark > leaf. Nutrient accumulation was 749.94 g and 1730.86 kg · hm(-2) for the individual tree of larch and the stand, respectively. Nutrient accumulation of stem was significantly higher than that of branch, bark and leaf, whether it was macro-nutrient or micro-nutrient. Averagely, 749.94 g nutrient elements would be removed from the system when a 19-year-old larch tree was harvested. If only the stem part was removed from the system, the removal of nutrient elements could be reduced by 40.7%.

Duff mound consumption and cambium injury for centuries-old western larch from prescribed burning in western Montana

Science.gov (United States)

Michael G. Harrington

2012-01-01

Western larch is one of the most fire-adapted conifers in western North America. Its historical perpetuation depended upon regular fire disturbances, which creates open stand conditions and mineral seedbeds. A stand of 200- to 500-year-old larch in western Montana with deep duff mounds resulting from an unusually long 150-year fire-free period was mechanically thinned...

The Potential Impact of CO2 and Air Temperature Increases on Krummholz's Transformation into Arborescent Form in the Southern Siberian Mountains

Science.gov (United States)

Kharuk, V. I.; Dvinskaya, M. L.; Im, S. T.; Ranson, K. J.

2011-01-01

Trees in the southern Siberian Mountains forest-tundra ecotone have considerably increased their radial and apical growth increments during the last few decades. This leads to the widespread vertical transformation of mat and prostrate krummholz forms of larch (Larix sibirica Ledeb) and Siberian pine (Pinus sibirica Du Tour). An analysis of the radial growth increments showed that these transformations began in the mid-1980s. Larch showed a greater resistance to the harsh alpine environment and attained a vertical growth form in areas where Siberian pine is still krummholz. Upper larch treeline is about 10 m higher than Siberian pine treeline. Observed apical and radial growth increment increases were correlated with CO2 concentration (r = 0.83-0.87), summer temperatures (r = 0.55-0.64), and "cold period" (i.e. September-May) air temperatures (r = 0.36-0.37). Positive correlation between growth increments and winter precipitation was attributed to snow cover protection for trees during wintertime.

Tissue culture of adult larch as a tool for breeding purposes

Energy Technology Data Exchange (ETDEWEB)

Ewald, D.; Kretzschmar, U. [Federal Research Centre of Forestry and Forest Products, Waldsieversdorf (Germany). Inst. for Forest Tree Biology

1995-12-31

Aimed at the identical reproduction of genotypes which are considered superior different methods were tested to establish and to propagate tissue cultures from old larch trees (L. decidua, L. kaempferi, L. sukaczewii, L. gmelinii, L. eurolepis). Serial subcultures without phytohormones (shoot tip propagation) led to the establishment of clone lines. After ten subcultures propagation velocity, shoot morphology and rooting behavior were similar to juvenile plant material. Serial subcultures which included a cytokinin induction led to the formation of adventitious shoot clusters (adventitious bud propagation). Adventitious shoots derived from male flowers of one L. kaempferi clone could be propagated via shoot tip propagation. Micrografting of meristems in vitro resulted in a regained rooting capacity of green cuttings from micrografts. Combining these in vitro techniques offers now the possibility to propagate selected mature larch trees for different breeding purposes. 23 refs, 5 figs, 2 tabs

Tissue culture of adult larch as a tool for breeding purposes

Energy Technology Data Exchange (ETDEWEB)

Ewald, D; Kretzschmar, U [Federal Research Centre of Forestry and Forest Products, Waldsieversdorf (Germany). Inst. for Forest Tree Biology

1996-12-31

Aimed at the identical reproduction of genotypes which are considered superior different methods were tested to establish and to propagate tissue cultures from old larch trees (L. decidua, L. kaempferi, L. sukaczewii, L. gmelinii, L. eurolepis). Serial subcultures without phytohormones (shoot tip propagation) led to the establishment of clone lines. After ten subcultures propagation velocity, shoot morphology and rooting behavior were similar to juvenile plant material. Serial subcultures which included a cytokinin induction led to the formation of adventitious shoot clusters (adventitious bud propagation). Adventitious shoots derived from male flowers of one L. kaempferi clone could be propagated via shoot tip propagation. Micrografting of meristems in vitro resulted in a regained rooting capacity of green cuttings from micrografts. Combining these in vitro techniques offers now the possibility to propagate selected mature larch trees for different breeding purposes. 23 refs, 5 figs, 2 tabs

[CO2 flux characteristics and their influence on the carbon budget of a larch plantation in Maoershan region of Northeast China].

Science.gov (United States)

Qiu, Ling; Zu, Yuan-Gang; Wang, Wen-Jie; Sun, Wei; Su, Dong-Xue; Zheng, Guang-Yu

2011-01-01

From January to December 2008, the CO2 flux in a larch plantation (Larix gmeilinii) in Maoershan region of Shangzhi County, Heilongliang Province was measured by eddy covanance method, and the diurnal changes of leaf photosynthetic rate were measured in growth season (from May to October). There existed differences in the net ecosystem exchange (NEE) of the plantation in different time periods under the effects of environmental factors. In the afternoon (12:00-24:00), the NEE changed more slowly with the variation of vapor pressure deficit (VPD) than in the morning (0:00-12:00); and in the morning, tbe light use efficiency was 0.6284 mol x mol(-1), 14% more than that in afternoon. The NEE increased with increasing temperature, and the increment in the morning was 50% higher than that in the afternoon (air temperature > 15 degrees C). These differences in responding to environmental changes led to 88% NEE implemented in the morning, and only 12% NEE implemented in the afternoon. The annual gross ecosystem productivity (GEP) in the morning took a percentage of 60%, and that in afternoon took 40%. These findings were supported by the observation at leaf level, i.e., on average of whole growth season, the leaf photosynthetic capacity in the morning was over 2-fold higher than that in afternoon. Generally, the annual NEE, ecosystem respiration (Re), and GEP of the plantation in 2008 were 263-264 g C x m(-2), 718-725 g C x m(-2), and 981-989 g C x m(-2), respectively.

Driving Factors of Understory Evapotranspiration within a Siberian Larch Forest

Science.gov (United States)

Tobio, A.; Loranty, M. M.; Kropp, H.; Pena, H., III; Alexander, H. D.; Natali, S.; Kholodov, A. L.; Spawn, S.; Farmer, S.

2017-12-01

Amplified rates of climate change are causing alterations in vegetation productivity, hydrologic cycling, and wildfire severity and intensity in arctic ecosystems. Boreal larch forests in northeastern Siberia are a critical but understudied ecosystem that are affected by these modifications. These forests cover 2.5 million km2 with densities ranging from spare to thick. The current average canopy cover is at around 17% and is expected to increase with the observed increases in vegetation productivity and wildfire. These projected changes in forest density can alter the proportional contributions of over- and understory vegetation to whole ecosystem evapotranspiration. Low density boreal forests have much higher rates of understory evapotranspiration and can contribute as much as 80% to total ecosystem evapotranspiration, while the understory in high density forests is responsible for only around 15% of total ecosystem evapotranspiration. The objective of this research is to understand why there are changes in understory evapotranspiration with varying overstory density by looking at light levels, biomass, vegetation, and air and soil differences. To better learn about these differences in understory evapotranspiration in boreal larch forests the driving factors of evapotranspiration were measured within a burn scar with varying densities of high, medium, and low. Water fluxes were conducted using the static chamber technique under different environmental conditions. Furthermore, controlling factors of evapotranspiration such as photosynethically active radiation, vapor pressure deficit, soil moisture, moss cover, biomass, and leaf area index were measured or derived. In general, we found that low density areas have highest rates of evapotranspiration due to larger amount of biomass, and increased access to light, despite low levels of soil moisture. These results can help us understand how and why total ecosystem water exchange will change in boreal larch forests

Larch Forests of Middle Siberia: Long-Term Trends in Fire Return Intervals

Science.gov (United States)

Kharuk, Viacheslav I.; Dvinskaya, Mariya L.; Petrov, Ilya A.; Im, Sergei T.; Ranson, Kenneth J.

2016-01-01

Fire history within the northern larch forests of Central Siberia was studied (65 + deg N). Fires within this area are predominantly caused by lightning strikes rather than human activity. Mean fire return intervals (FRIs) were found to be 112 ± 49 years (based on fire scars) and 106 ± 36 years (based on fire scars and tree natality dates). FRI were increased with latitude increase and observed to be about 80 years at 64 deg N, about 200 years near the Arctic Circle and about 300 years nearby the northern range limit of larch stands (approximately 71 deg + N). Northward FRI increase correlated with incoming solar radiation (r = -0.95). Post Little Ice Age (LIA) warming (after 1850) caused approximately a doubling of fire events (in comparison with a similar period during LIA). The data obtained support a hypothesis of climate-induced fire frequency increase.

Carbon and oxygen isotope signatures in conifers from the Swiss National Park

Science.gov (United States)

Churakova (Sidorova), Olga; Saurer, Matthias; Siegwolf, Rolf; Bryukhanova, Marina; Bigler, Christof

2015-04-01

Our study investigates the physiological response and plasticity of trees under climatic changes for larch (Larix decidua) and mountain pine (Pinus mugo var. uncinata) in the Swiss National Park.This research was done in the context of investigation tree mortality and their potential to survive under the harsh mountainous conditions. For the stable isotope analysis we selected four mountain pine and four larch trees from each a south- and north-facing slope. Oxygen isotope ratios can give insight into water sources and evaporative processes. To understand the differential response of mountain pine and larch to short-term climatic changes we measured 18O/16O in water extracted from twigs and needles as well as soil samples for each species at both sites. The seasonal variabilities in 18O/16O needles and twigs of mountain pine and larch trees as well as soil samples were related to changes in climate conditions from end of May until middle of October. To reveal the main climatic factors driving tree growth of pine and larch trees in the long-term, tree-ring width chronologies were built and bulk 18O/16O, 13C/12C wood chronologies were analyzed and correlated with climatic parameters over the last 100 years. The results indicate a strong influence of spring and summer temperatures for larch trees, while variation of spring and summer precipitations is more relevant for mountain pine trees. This work is supported by the Swiss National Science Foundation, Marie-Heim Vögtlin Program PMPDP-2 145507

Climate impact on the tree growth, vigor and productivity in Siberia

Science.gov (United States)

Kharuk, V.; Im, S.; Petrov, I.; Dvinskaya, M.

2017-12-01

Changing climate has an impact on the Siberian taiga forests. We analyzed GPP and NPP trends, growth index, and stands mortality within the Central Siberia (48°- 75°N/80°-115°E). Considered forests included larch-dominant (Larix sibirica, L. dahurica) and "dark needle conifer" (DNC: Abies sibirica, Pinus sibirica, Picea obovata) stands. GPP and NPP trends calculated based on the Terra/MODIS products. Growth index calculations based on dendrochronology data. Water stress analysis based on the gravimetric and microwave satellite data and MERRA-2 database. Analyzed variables included precipitation, air temperature, VPD, drought index SPEI, and root zone wetness. We found positive GPP trends within majority (>90%) of larch-dominant and DNC ranges, whereas NPP trends are positive on the +10C°) temperatures and vegetation period length. During recent years larch experience water stress in the beginning of vegetation period. Tree decline and mortality observed within DNC stands, and that phenomenon regularly coincided with zones of negative NPP trends. Mortality correlated with VPD, SPEI, and root zone moisture content. Bark beetles (including aggressive species Polygraphus proximus, similar to Dendroctonus ponderosae in American forests) attacked water-stressed trees. Geographically, mortality began on the margins of the DNC range (e.g., within the forest-steppe ecotone) and on terrain features with maximal water stress risk (narrow-shaped hilltops, convex steep south facing slopes, shallow well-drained soils). Currently, Siberian pine and fir decline observed within southern range of these species. In addition, air temperature and aridity increase promotes Siberian silkmoth (Dendrolimus sibiricus) outbreak that occurred about one degree northward of formerly range. Observing and predicting aridity increase will lead to the replacement of Siberian pine and fir within southern range of these species with more tolerant species (e.g., Pinus sylvestris, Larix spp.).

Processing of spruce and larch resins to obtain balsam for the confection industry

Energy Technology Data Exchange (ETDEWEB)

Buinova, E.F.; Yaremchenko, N.G.; Izotova, L.V.; Lepeiko, A.G.; Meteshkina, L.P.; Zhuravlev, P.I.; Chumakov, V. A.; Nikiforova, V.N.; Krylova, E.N.

1981-01-01

Modified balsam was prepared by esterification of purified and precipitated larch or spruce oleoresins with glycerol at 255-265 degrees for 4-6 hours. The modified balsams, which were obtained in 55-65% yield, can be used as a base for chewing gum manufacture.

Cell Wall Property Changes of White Rot Larch during Decay Process

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Weiwei Shangguan

2014-06-01

Full Text Available Larch flakes infested with white rot fungus were examined following several infestation durations with respect to the mass loss, tensile strength, hardness, porosity, and change in cell wall components. Nano-indentation, X-ray diffraction (XRD, nitrogen adsorption, and Fourier transform infrared (FTIR spectroscopy testing methods were employed to investigate the property changes during the decay process. The testing results showed that the mass loss was greater and the longitudinal tensile strength decreased following the first three-week infestation. Nano-indentation measurements revealed that the average MOE of infested larch flakes decreased from 24.0 to 17.1 GPa and the average hardness declined from 528.47 to 427.87 MPa following 12 weeks of infestation. After the first three weeks, the relative crystallinity, surface area, and micropore area of the infested samples increased. These parameters decreased after three weeks had elapsed. Changes in the absorption peaks observed in FTIR explained that the first three-week infestation had a strong effect on the mass loss and strength changes. This suggests that white rot fungus intensely attacked the lignin component of the biomass during the first three weeks of infestation.

Boreal Tree Light- and Water-Use: Asynchronous, Diverging, yet Complementary

Science.gov (United States)

Pappas, C.; Baltzer, J. L.; Barr, A.; Black, T. A.; Bohrer, G.; Detto, M.; Maillet, J.; Matheny, A. M.; Roy, A.; Sonnentag, O.; Stephens, J.

2017-12-01

Water stress has been suggested as a key mechanism behind the contemporary increase in tree mortality rates in northwestern North America. However, a detailed analysis of boreal tree light- and water-use strategies as well as their interspecific differences are still lacking. Here, we examine the tree hydraulic behaviour of co-occurring larch (Larix laricina) and black spruce (Picea mariana), two characteristic boreal tree species, near the southern limit of the boreal ecozone in central Canada. Sap flux density (Js) and concurrently recorded stem radius fluctuations and meteorological conditions are used to quantify tree hydraulic functioning and to scrutinize tree light- and water-use strategies. Our analysis reveals an asynchrony in the diel hydrodynamics of the two species with the initial rise in Js occurring two hours earlier in larch than in black spruce. Structural differences in the crown architecture of larch and black spruce lead to interspecific differences in light harvesting that can explain the observed asynchrony in their hydraulic function. Furthermore, the two species exhibit diverging stomatal regulation strategies with larch employing relatively isohydric whereas black spruce anisohydric behaviour. Such asynchronous and diverging tree-level light- and water-use strategies provide new insights into the ecosystem-level complementarity of tree form and function, with implications for understanding boreal forests' water and carbon dynamics and resilience to environmental stress.

Population Spatial Dynamics of Larix potaninii in Alpine Treeline Ecotone in the Eastern Margin of the Tibetan Plateau, China

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Jia’nan Cui

2017-09-01

Full Text Available The high-altitude treeline is known to be sensitive to climate variability, and is thus considered as a bio-monitoring indicator of climate change. However, our understanding of the population dynamics and the cumulative climate-change effects on the alpine treeline ecotone in recent decades is limited. Here, we investigated the population dynamics of Larix potainii on the south- and north-facing slopes in the alpine treeline ecotone in the eastern margin of the Tibetan Plateau, China, including treeline position, population density, and tree recruitment. Results showed that on both south- and north-facing slopes, the treeline did not show a significant advancement in the past four decades. The population was dominated by young individuals, which tend to be established in the lower areas. Larix, here, tends to be clustered, especially in the upper areas. However, population density increased dramatically only on north-facing slopes. Larix here suffer from the stressful environment, but the warmer winter due to climate warming could facilitate the vertical growth of seedlings and saplings. Aggregated spatial patterns also provide a positive feedback in ameliorating the harsh environment. The slope-climate-moisture interactions have a pronounced impact on tree recruitment, including snow-limited tree establishment on the north-facing slopes and moisture-limited tree establishment on the south-facing slopes.

Dissimilar responses of larch stands in northern Siberia to increasing temperatures-a field and simulation based study.

Science.gov (United States)

Wieczorek, Mareike; Kruse, Stefan; Epp, Laura S; Kolmogorov, Alexei; Nikolaev, Anatoly N; Heinrich, Ingo; Jeltsch, Florian; Pestryakova, Lyudmila A; Zibulski, Romy; Herzschuh, Ulrike

2017-09-01

Arctic and alpine treelines worldwide differ in their reactions to climate change. A northward advance of or densification within the treeline ecotone will likely influence climate-vegetation feedback mechanisms. In our study, which was conducted in the Taimyr Depression in the North Siberian Lowlands, w present a combined field- and model-based approach helping us to better understand the population processes involved in the responses of the whole treeline ecotone, spanning from closed forest to single-tree tundra, to climate warming. Using information on stand structure, tree age, and seed quality and quantity from seven sites, we investigate effects of intra-specific competition and seed availability on the specific impact of recent climate warming on larch stands. Field data show that tree density is highest in the forest-tundra, and average tree size decreases from closed forest to single-tree tundra. Age-structure analyses indicate that the trees in the closed forest and forest-tundra have been present for at least ~240 yr. At all sites except the most southerly ones, past establishment is positively correlated with regional temperature increase. In the single-tree tundra, however, a change in growth form from krummholz to erect trees, beginning ~130 yr ago, rather than establishment date has been recorded. Seed mass decreases from south to north, while seed quantity increases. Simulations with LAVESI (Larix Vegetation Simulator) further suggest that relative density changes strongly in response to a warming signal in the forest-tundra while intra-specific competition limits densification in the closed forest and seed limitation hinders densification in the single-tree tundra. We find striking differences in strength and timing of responses to recent climate warming. While forest-tundra stands recently densified, recruitment is almost non-existent at the southern and northern end of the ecotone due to autecological processes. Palaeo-treelines may therefore

Study on adsorption and remediation of heavy metals by poplar and larch in contaminated soil.

Science.gov (United States)

Wang, Xin; Jia, Youngfeng

2010-08-01

Field experiments at the Shenyang Experimental Station of Ecology were conducted to study the adsorption, accumulation, and remediation of heavy metals by poplar and larch grown in artificially contaminated soil. The soil was spiked with a combination of Cd, Cu, and Zn at concentrations of 1.5, 100, and 200 mg.kg(-1), respectively. The results showed that the biomass of poplar (Populus canadensis Moench) was lower by 26.0% in the soil spiked with a mixture of Cd, Cu, and Zn, compared with the control. Concentrations of Cd in poplar leaf and Cu in poplar roots in the treated soil were 4.11 and 14.55 mg kg(-1), respectively, which are much greater than in corresponding controls. The migration of heavy metals in woody plant body was in the order Cd > Zn > Cu. Poplar had higher metal concentrations in aboveground tissues and a higher biomass compared with larch of the same age and therefore is potentially more suitable for remediation. In the heavy metal-polluted soil of this study, phytoremediation by poplar may take 56 and 245 years for Cd and Cu, respectively, for meeting the soil standards of heavy metals, and the corresponding phytoremediation times by larch would take 211 and 438 years. The research findings could be used as a basis to develop ecological engineering technologies for environmental control and remediation of pollution caused by heavy metals in soils.

[The intensity of phytodetrite decomposition in Larch Forest of the permafrost zone in central Siberia].

Science.gov (United States)

Prokushkin, S G; Prokushkin, A S; Sorokin, N D

2014-01-01

Based on the results of long-term investigations, quantitative assessment ofphytodetrite mineralization rates is provided. Their role in the biological cycle of larch stands growing in the permafrost zone of Central Evenkia is discussed. It is demonstrated that their destruction in the subshrub-sphagnum and cowberry-green moss larch stands is extremely slow, the plant litter contains the most cecalcitrant organic matter demonstrating the lowest decomposition coefficient of 0.03-0.04 year(-1), whereas fresh components of the plant litter have 3- to 4-fold higher values. An insignificant input of N and C from the analyzed mortmass to the soil has been registered. It has been revealed that the changes in N and C in the decomposition components are closely related to the quantitative dynamics (biomass) of microorganisms, such as hydrolytics and, especially, micromicetes.

Forest decline caused by high soil water conditions in a permafrost region

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H. Iwasaki

2010-02-01

Full Text Available In the permafrost region near Yakutsk, eastern Siberia, Russia, annual precipitation (June–May in 2005–2006 and 2006–2007 exceeded the 26-year (1982–2008 mean of 222±68 mm by 185 mm and 128 mm, respectively, whereas in 2007–2008 the excedent was only 48 mm, well within the range of variability. Yellowing and browning of larch (Larix cajanderi Mayr. trees occurred in an undisturbed forest near Yakutsk in the 2007 summer growing season. Soil water content at a depth of 0.20 m was measured along a roughly 400 m long line transect running through areas of yellowing and browning larch trees (YBL and of normal larch trees (NL. In the two years of supranormal precipitation, soil water content was very high compared to values recorded for the same area in previous studies. For both wet years, the mean degree of saturation (s was significantly greater in YBL than NL areas, whereas the converse was the case for the gas diffusivity in soil. This implies that rather than mitigating water stress suffered during normal precipitation years, elevated soil water conditions adversely affected the growth of larch trees. Eastern Siberia's taiga forest extends widely into the permafrost region. Was such supranormal annual precipitation to extend for more than two years, as might be expected under impending global climate changes, forest recovery may not be expected and emission of greenhouse gas might continue in future.

Geographic variation, genetic structure, and conservation unit designation in the Larch Mountain salamander (Plethodon larselli).

Science.gov (United States)

R. Steven Wagner; Mark P. Miller; Charles M. Crisafulli; Susan M. Haig

2005-01-01

The Larch Mountain salamander (Plethodon larselli Burns, 1954) is an endemic species in the Pacific northwestern United States facing threats related to habitat destruction. To facilitate development of conservation strategies, we used DNA sequences and RAPDs (random amplified polymorphic DNA) to examine differences among populations of this...

Surface forcing of non-stand-replacing fires in Siberian larch forests

Science.gov (United States)

Chen, Dong; Loboda, Tatiana V.

2018-04-01

Wildfires are the dominant disturbance agent in the Siberian larch forests. Extensive low- to mediate-intensity non-stand-replacing fires are a notable property of fire regime in these forests. Recent large scale studies of these fires have focused mostly on their impacts on carbon budget; however, their potential impacts on energy budget through post-fire albedo changes have not been considered. This study quantifies the post-fire surface forcing for Siberian larch forests that experienced non-stand-replacing fires between 2001 and 2012 using the full record of MODIS MCD43A3 albedo product and a burned area product developed specifically for the Russian forests. Despite a large variability, the mean effect of non-stand-replacing fires imposed through albedo is a negative forcing which lasts for at least 14 years. However, the magnitude of the forcing is much smaller than that imposed by stand-replacing fires, highlighting the importance of differentiating between the two fire types in the studies involving the fire impacts in the region. The results of this study also show that MODIS-based summer differenced normalized burn ratio (dNBR) provides a reliable metric for differentiating non-stand-replacing from stand-replacing fires with an overall accuracy of 88%, which is of considerable importance for future work on modeling post-fire energy budget and carbon budget in the region.

Résilience de l'approvisionnement en eau de deux villes de l'arche ...

International Development Research Centre (IDRC) Digital Library (Canada)

Résilience de l'approvisionnement en eau de deux villes de l'arche sèche du Panama. Ce projet augmentera la résilience au stress hydrique des villes de Chitré et de La Villa de los Santos, au Panama, face aux effets négatifs de la variabilité du climat et des changements climatiques. Risques liés au climat au Panama

Effects of elevated CO2 concentration on growth, annual ring structure and photosynthesis in Larix kaempferi seedlings

International Nuclear Information System (INIS)

Yazaki, K.; Ishida, S.; Kawagishi, T.; Fukatsu, E.; Funada, R.; Maruyama, Y.; Kitao, M.; Tobita, H.; Koike, T.

2004-01-01

The effects of elevated carbon dioxide concentration and two nutrient regimes on stem growth rate, annual ring structure and temporal variations in photosynthetic characteristics of seedlings of Japanese larch were evaluated. When compared with ambient carbon dioxide, elevated carbon dioxide reduced stem height and increased stem basal diameter, but had no significant effect on ring width or the number of tracheids per radial file. No obvious difference was observed in cell wall thickness or the relative area of cell wall between seedlings grown in ambient or elevated carbon dioxide. Net assimilation rate increased in the presence of elevated carbon dioxide, however, the increase in whole-crown photosynthetic rate was minimal due to the smaller needle area and acclimation of the photosynthetic characteristics of the needles to the growth in carbon dioxide concentration. Conclusion: elevated carbon dioxide concentration did not appear to significantly affect the capacity of stems of Japanese larch seedlings for carbon fixation for use in cell wall synthesis, although there was evidence of change in the temporal pattern of stem growth and stem thickening. 52 refs., 3 tabs., 4 figs

Opposing effects of fire severity on climate feedbacks in Siberian larch forests

Science.gov (United States)

Loranty, M. M.; Alexander, H. D.; Natali, S.; Kropp, H.; Mack, M. C.; Bunn, A. G.; Davydov, S. P.; Erb, A.; Kholodov, A. L.; Schaaf, C.; Wang, Z.; Zimov, N.; Zimov, S. A.

2017-12-01

Boreal larch forests in northeastern Siberia comprise nearly 25% of the continuous permafrost zone. Structural and functional changes in these ecosystems will have important climate feedbacks at regional and global scales. Like boreal ecosystems in North America, fire is an important determinant of landscape scale forest distribution, and fire regimes are intensifying as climate warms. In Siberian larch forests are dominated by a single tree species, and there is evidence that fire severity influences post-fire forest density via impacts on seedling establishment. The extent to which these effects occur, or persist, and the associated climate feedbacks are not well quantified. In this study we use forest stand inventories, in situ observations, and satellite remote sensing to examine: 1) variation in forest density within and between fire scars, and 2) changes in land surface albedo and active layer dynamics associated with forest density variation. At the landscape scale we observed declines in Landsat derived albedo as forests recovered in the first several decades after fire, though canopy cover varied widely within and between individual fire scars. Within an individual mid-successional fire scar ( 75 years) we observed canopy cover ranging from 15-90% with correspondingly large ranges of albedo during periods of snow cover, and relatively small differences in albedo during the growing season. We found an inverse relationship between canopy density and soil temperature within this fire scar; high-density low-albedo stands had cooler soils and shallower active layers, while low-density stands had warmer soils and deeper active layers. Intensive energy balance measurements at a high- and low- density site show that canopy cover alters the magnitude and timing of ground heat fluxes that affect active layer properties. Our results show that fire impacts on stand structure in Siberian larch forests affect land surface albedo and active layer dynamics in ways that

CITOGENETICS EFFECTS INDUCED BY THE ASCORBIC ACID TREATMENT OF LARIX DECIDUA MILL. SSP. CARPATICA AND PICEA ABIES (L. KARST

Directory of Open Access Journals (Sweden)

Ioana Ieremia

2006-08-01

Full Text Available The paper present the influence of ascorbic acid upon the mitotic division of Larix decidua Mill ssp. carpatica and Picea abies (L. Karst. The treatment is applied of two variants, germinated seed in ascorbic acid (variantAand germinated seeds in disttilate water, than treated with ascorbic acid in 3 concentrations (variant B.

Results of growing relatively smoke resistant types of trees and their practical use. [German Democratic Republic

Energy Technology Data Exchange (ETDEWEB)

Tzschacksch, O.

1985-01-01

Achievements in cultivating sulfur dioxide resistant conifers in the German Democratic Republic are summarized. These conifers will be planted in afforestation programs in smoke damage zones I, i.e. in conifer forests at high elevations with maximum pollution damage. Nurseries with the most promising tree types have been established for harvesting seeds for propagation. Cultivation of cuttings and tree grafting is carried out in experimental nurseries along with laboratory gas treatment tests. Smoke resistant varieties of the common spruce Picae abies (L.) show vigorous growth in smoke damage zone I. Other spruce types suitable for cultivation are Picea pungens Engelm., Picea omorica (Panc.) Purk. with the highest vitality in 15 to 20 year old trial plantings in smoke damage zone I extreme, and Picea glanca, rubens and orientalis. Suitable pines are Pinus contorta Dougl. ex Loud. (Murray pine), Pinus mugo Turra, and others; resistant larches are Larix decidua and Larix leptolepis. Deciduous trees being cultivated for afforestation are aspens (Populus tremula L.) and mountain ash (Sorbus aucuparia L.). 11 references.

Adsorption recovery of thorium(IV) by Myrica rubra tannin and larch tannin immobilized onto collagen fibres

International Nuclear Information System (INIS)

Xuepin Liao; Li Li; Bi Shi

2004-01-01

Novel adsorbents which can concentrate Th(IV) in aqueous solution were prepared by immobilizing Myrica rubra tannin and larch tannin onto collagen fibre matrices. The adsorption capacities of the immobilized tannins to Th(IV) are related to temperature and pH value of the adsorption process. For example, when the initial concentration of Th(IV) was 116.0 mg x l -1 and the immobilized tannin was 100 mg, the adsorption capacities of immobilized Myrica rubra tannin and larch tannin were 55.98 mg Th(IV) x g -1 and 13.19 mg Th(IV) x g -1 , respectively at 303 K, and 73.67 mg Th(IV) x g -1 and 18.19 mg Th(IV) x g -1 at 323 K. It was also found that the higher adsorption capacity was obtained at higher pH value. The adsorption equilibrium data of the immobilized tannins for Th(IV) can be well fitted by the Langmuir model and the mechanism of the adsorption was found to be a chemical adsorption. In general, the adsorption capacity of immobilized Myrica rubra tannin to Th(IV) is significantly higher than that of immobilized larch tannin, probably due to the fact that the B ring of Myrica rubra tannin has a pyrogallol structure which has higher reaction activity with metal ions. The breakthrough point of the adsorption column of immobilized Myrica rubra tannin was at 33 bed volumes for the experimental system. The mass transfer coefficient of adsorption column determined by Adams-Bohart equation was 1.61 x 10 -4 l x mg -1 x min -1 . The adsorption column can be easily regenerated by 0.1 mol x l -1 HNO 3 solution, showing outstanding ability of concentrating Th(IV). (author)

Protective Effect of Nitric Oxide (NO against Oxidative Damage in Larix gmelinii Seedlings under Ultraviolet-B Irradiation

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Haiqing Hu

2016-10-01

Full Text Available Ultraviolet-B (UV-B stress appears to be more striking than other research works because of the thin ozone layer. The protective influence of an exogenous nitric oxide donor and sodium nitroprusside (SNP on the growth properties of Larix gmelinii seedlings was investigated under ultraviolet-B radiation conditions. The results indicated that 0.1 mM SNP could effectively alleviate the damage caused by ultraviolet-B radiation, and improved the seedling growth properties, the relative water content, and photosynthetic pigment content in leaves. Additionally, the photosynthetic capacity and antioxidant enzyme activity were increased during the exposure. On the contrary, the damage caused by active oxygen was decreased in SNP-treated seedling leaves. The damage caused by ultraviolet-B radiation was slightly reduced after treating with 0.01 mM SNP. Nevertheless, treatment with 0.5 mM SNP had a negative effect under ultraviolet-B radiation. Furthermore, supplementing NO (nitric oxide improved the photosynthetic capacity and antioxidant enzyme activity and alleviated the damage of caused by active oxygen. The best effective concentration of SNP was 0.1 mM. Therefore, a suitable amount of exogenous NO can protect the Larix gmelinii seedlings and increase their tolerance to ultraviolet-B radiation.

Simulating carbon and water cycles of larch forests in East Asia by the BIOME-BGC model with AsiaFlux data

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M. Ueyama

2010-03-01

Full Text Available Larch forests are widely distributed across many cool-temperate and boreal regions, and they are expected to play an important role in global carbon and water cycles. Model parameterizations for larch forests still contain large uncertainties owing to a lack of validation. In this study, a process-based terrestrial biosphere model, BIOME-BGC, was tested for larch forests at six AsiaFlux sites and used to identify important environmental factors that affect the carbon and water cycles at both temporal and spatial scales.

The model simulation performed with the default deciduous conifer parameters produced results that had large differences from the observed net ecosystem exchange (NEE, gross primary productivity (GPP, ecosystem respiration (RE, and evapotranspiration (ET. Therefore, we adjusted several model parameters in order to reproduce the observed rates of carbon and water cycle processes. This model calibration, performed using the AsiaFlux data, substantially improved the model performance. The simulated annual GPP, RE, NEE, and ET from the calibrated model were highly consistent with observed values.

The observed and simulated GPP and RE across the six sites were positively correlated with the annual mean air temperature and annual total precipitation. On the other hand, the simulated carbon budget was partly explained by the stand disturbance history in addition to the climate. The sensitivity study indicated that spring warming enhanced the carbon sink, whereas summer warming decreased it across the larch forests. The summer radiation was the most important factor that controlled the carbon fluxes in the temperate site, but the VPD and water conditions were the limiting factors in the boreal sites. One model parameter, the allocation ratio of carbon between belowground and aboveground, was site-specific, and it was negatively correlated with the annual climate of annual mean air temperature and total precipitation

Simulating carbon and water cycles of larch forests in East Asia by the BIOME-BGC model with AsiaFlux data

Science.gov (United States)

Ueyama, M.; Ichii, K.; Hirata, R.; Takagi, K.; Asanuma, J.; Machimura, T.; Nakai, Y.; Ohta, T.; Saigusa, N.; Takahashi, Y.; Hirano, T.

2010-03-01

Larch forests are widely distributed across many cool-temperate and boreal regions, and they are expected to play an important role in global carbon and water cycles. Model parameterizations for larch forests still contain large uncertainties owing to a lack of validation. In this study, a process-based terrestrial biosphere model, BIOME-BGC, was tested for larch forests at six AsiaFlux sites and used to identify important environmental factors that affect the carbon and water cycles at both temporal and spatial scales. The model simulation performed with the default deciduous conifer parameters produced results that had large differences from the observed net ecosystem exchange (NEE), gross primary productivity (GPP), ecosystem respiration (RE), and evapotranspiration (ET). Therefore, we adjusted several model parameters in order to reproduce the observed rates of carbon and water cycle processes. This model calibration, performed using the AsiaFlux data, substantially improved the model performance. The simulated annual GPP, RE, NEE, and ET from the calibrated model were highly consistent with observed values. The observed and simulated GPP and RE across the six sites were positively correlated with the annual mean air temperature and annual total precipitation. On the other hand, the simulated carbon budget was partly explained by the stand disturbance history in addition to the climate. The sensitivity study indicated that spring warming enhanced the carbon sink, whereas summer warming decreased it across the larch forests. The summer radiation was the most important factor that controlled the carbon fluxes in the temperate site, but the VPD and water conditions were the limiting factors in the boreal sites. One model parameter, the allocation ratio of carbon between belowground and aboveground, was site-specific, and it was negatively correlated with the annual climate of annual mean air temperature and total precipitation. Although this study substantially

Variability in above- and belowground carbon stocks in a Siberian larch watershed

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E. E. Webb

2017-09-01

Full Text Available Permafrost soils store between 1330 and 1580 Pg carbon (C, which is 3 times the amount of C in global vegetation, almost twice the amount of C in the atmosphere, and half of the global soil organic C pool. Despite the massive amount of C in permafrost, estimates of soil C storage in the high-latitude permafrost region are highly uncertain, primarily due to undersampling at all spatial scales; circumpolar soil C estimates lack sufficient continental spatial diversity, regional intensity, and replication at the field-site level. Siberian forests are particularly undersampled, yet the larch forests that dominate this region may store more than twice as much soil C as all other boreal forest types in the continuous permafrost zone combined. Here we present above- and belowground C stocks from 20 sites representing a gradient of stand age and structure in a larch watershed of the Kolyma River, near Chersky, Sakha Republic, Russia. We found that the majority of C stored in the top 1 m of the watershed was stored belowground (92 %, with 19 % in the top 10 cm of soil and 40 % in the top 30 cm. Carbon was more variable in surface soils (10 cm; coefficient of variation (CV  =  0.35 between stands than in the top 30 cm (CV  =  0.14 or soil profile to 1 m (CV  =  0.20. Combined active-layer and deep frozen deposits (surface – 15 m contained 205 kg C m−2 (yedoma, non-ice wedge and 331 kg C m−2 (alas, which, even when accounting for landscape-level ice content, is an order of magnitude more C than that stored in the top meter of soil and 2 orders of magnitude more C than in aboveground biomass. Aboveground biomass was composed of primarily larch (53 % but also included understory vegetation (30 %, woody debris (11 % and snag (6 % biomass. While aboveground biomass contained relatively little (8 % of the C stocks in the watershed, aboveground processes were linked to thaw depth and

Volume and weight characteristics of a typical Douglas-fir/ western larch stand, Coram Experimental Forest, Montana

Science.gov (United States)

Robert E. Benson; Joyce A. Schlieter

1980-01-01

An over-mature Douglas-fir/western larch stand on the Coram Experimental Forest in Montana averaged about 7,300 ft3/acre (511 rn3/ha) of wood over 3 inches (7.62 cm) in diameter, and an additional 57 tons/acre (128/ha) of fine material, before harvest. After logging, using three different cutting methods and four different levels of utilization, wood residues ranged...

Physiological responses of three deciduous conifers (Metasequoia glyptostroboides, Taxodium distichum and Larix laricina) to continuous light: adaptive implications for the early Tertiary polar summer.

Science.gov (United States)

Equiza, M Alejandra; Day, Michael E; Jagels, Richard

2006-03-01

Polar regions were covered with extensive forests during the Cretaceous and early Tertiary, and supported trees comparable in size and productivity to those of present-day temperate forests. With a winter of total or near darkness and a summer of continuous, low-angle illumination, these temperate, high-latitude forests were characterized by a light regime without a contemporary counterpart. Although maximum irradiances were much lower than at mid-latitudes, the 24-h photoperiod provided similar integrated light flux. Taxodium, Larix and Metasequoia, three genera of deciduous conifers that occurred in paleoarctic wet forests, have extant, closely related descendents. However, the contemporary relative abundance of these genera differs greatly from that in the paleoarctic. To provide insight into attributes that favor competitive success in a continuous-light environment, we subjected saplings of these genera to a natural photoperiod or a 24-h photoperiod and measured gas exchange, chlorophyll fluorescence, non-structural carbohydrate concentrations, biomass production and carbon allocation. Exposure to continuous light significantly decreased photosynthetic capacity and quantum efficiency of photosystem II in Taxodium and Larix, but had minimal influence in Metasequoia. In midsummer, foliar starch concentration substantially increased in both Taxodium and Larix saplings grown in continuous light, which may have contributed to end-product down-regulation of photosynthetic capacity. In contrast, Metasequoia allocated photosynthate to continuous production of new foliar biomass. This difference in carbon allocation may have provided Metasequoia with a two fold advantage in the paleoarctic by minimizing depression of photosynthetic capacity and increasing photosynthetic surface.

Woody species diversity in forest plantations in a mountainous region of Beijing, China: effects of sampling scale and species selection.

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Yuxin Zhang

Full Text Available The role of forest plantations in biodiversity conservation has gained more attention in recent years. However, most work on evaluating the diversity of forest plantations focuses only on one spatial scale; thus, we examined the effects of sampling scale on diversity in forest plantations. We designed a hierarchical sampling strategy to collect data on woody species diversity in planted pine (Pinus tabuliformis Carr., planted larch (Larix principis-rupprechtii Mayr., and natural secondary deciduous broadleaf forests in a mountainous region of Beijing, China. Additive diversity partition analysis showed that, compared to natural forests, the planted pine forests had a different woody species diversity partitioning pattern at multi-scales (except the Simpson diversity in the regeneration layer, while the larch plantations did not show multi-scale diversity partitioning patterns that were obviously different from those in the natural secondary broadleaf forest. Compare to the natural secondary broadleaf forests, the effects of planted pine forests on woody species diversity are dependent on the sampling scale and layers selected for analysis. Diversity in the planted larch forest, however, was not significantly different from that in the natural forest for all diversity components at all sampling levels. Our work demonstrated that the species selected for afforestation and the sampling scales selected for data analysis alter the conclusions on the levels of diversity supported by plantations. We suggest that a wide range of scales should be considered in the evaluation of the role of forest plantations on biodiversity conservation.

Population Spatial Dynamics of Larix potaninii in Alpine Treeline Ecotone in the Eastern Margin of the Tibetan Plateau, China

OpenAIRE

Jia’nan Cui; Jihong Qin; Hui Sun

2017-01-01

The high-altitude treeline is known to be sensitive to climate variability, and is thus considered as a bio-monitoring indicator of climate change. However, our understanding of the population dynamics and the cumulative climate-change effects on the alpine treeline ecotone in recent decades is limited. Here, we investigated the population dynamics of Larix potainii on the south- and north-facing slopes in the alpine treeline ecotone in the eastern margin of the Tibetan Plateau, China, includ...

Species presence frequency and diversity in different patch types along an altitudinal gradient: Larix chinensis Beissn in Qinling Mountains (China

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Minyi Huang

2016-03-01

Full Text Available Forest communities are mosaic systems composed of patches classified into four different developmental patch types: gap patch (G, building patch (B, mature patch (M and degenerate patch (D. To study the mechanisms maintaining diversity in subalpine coniferous forests, species presence frequency and diversity in the four distinct patch types (G, B, M and D of Larix chinensis conifer forests at three altitudinal gradients in the Qinling Mountains were analyzed. Our results were as follows: (1 Different species (or functional groups had distinct presence frequencies in the four different patch types along the altitudinal gradient; (2 Some species or functional groups (species groups sharing similar traits and responses to the environment only occurred in some specific patches. For seed dispersal, species using wind mainly occurred in G and D, while species using small animals mainly occurred in B and M; (3 Species composition of adjacent patch types was more similar than non-adjacent patch types, based on the lower β diversity index of the former; (4 The maximum numbers of species and two diversity indices (D′ and H′ were found in the middle altitudes. Various gap-forming processes and dispersal limitation may be the two major mechanisms determining species diversity in Larix chinensis coniferous forests at the patch scale.

Scientific Opinion on taxifolin-rich extract from Dahurian Larch (Larix gmelinii)

DEFF Research Database (Denmark)

Sjödin, Anders Mikael

2017-01-01

to non-alcoholic beverages, to yogurt and to chocolate confectionery. The Panel considers that the data on genotoxicity do not raise concern. In a subchronic rat study performed in accordance with OECD standards, the highest dose tested (i.e. 1,500 mg/kg bw) was considered to be the NOAEL. The margin...

Soil respiration rate on the contrasting north- and south-facing slopes of a larch forest in central Siberia

International Nuclear Information System (INIS)

Yanagihara, Y.; Koike, T.; Matsuura, Y.; Mori, S.; Shibata, H.; Satoh, F.; Masuyagina, O.V.; Zyryanova, O.A.; Prokushkin, A.S.; Prokushkin, S.G.; Abaimov, A.P.

2000-01-01

In an attempt to evaluate global warming effects, we measured the soil respiration of the contrasting north- and south- facing slopes of a larch forest in central Siberia, located at Tura City in the Krasnoyarsk District, Russia. The north-facing slope is assumed to be the present condition while the south-facing slope may stand for the future warm condition. As a result of differences in solar radiation, there were clear differences between the north- and south- facing slopes in terms, for example, of the active layer as the growth rate of larch trees. The soil respiration rate was higher on the south-facing slope than on the north-facing slope. At the temperature of 15°C, soil respiration rate of the south-facing slope was ca. 6.2 μ mol CO 2 * m -2 s -1 , which was about 0.6 times lower than that of broad-leaved forests in Hokkaido. There was an exponential correlation between soil temperature at 10 cm depth and the efflux of CO 2 from the soil surface. Various conditions (soil temperature,. nitrogen content and soil water content) seemed to be more favorable for soil respiration on the south-facing slope. (author)

Stage-specific regulation of four HD-ZIP III transcription factors during polar pattern formation in Larix leptolepis somatic embryos.

Science.gov (United States)

Li, Shui-gen; Li, Wan-feng; Han, Su-ying; Yang, Wen-hua; Qi, Li-wang

2013-06-15

Polar auxin transport provides a developmental signal for cell fate specification during somatic embryogenesis. Some members of the HD-ZIP III transcription factors participate in regulation of auxin transport, but little is known about this regulation in somatic embryogenesis. Here, four HD-ZIP III homologues from Larix leptolepis were identified and designated LaHDZ31, 32, 33 and 34. The occurrence of a miR165/166 target sequence in all four cDNA sequences indicated that they might be targets of miR165/166. Identification of the cleavage products of LaHDZ31 and LaHDZ32 in vivo confirmed that they were regulated by miRNA. Their mRNA accumulation patterns during somatic embryogenesis and the effects of 1-N-naphthylphthalamic acid (NPA) on their transcript levels and somatic embryo maturation were investigated. The results showed that the four genes had higher transcript levels at mature stages than at the proliferation stage, and that NPA treatment down-regulated the mRNA abundance of LaHDZ31, 32 and 33 at cotyledonary embryo stages, but had no effect on the mRNA abundance of LaHDZ34. We concluded that these four members of Larix HD-ZIP III family might participate in polar auxin transport and the development of somatic embryos, providing new insights into the regulatory mechanisms of somatic embryogenesis. Copyright © 2013 Elsevier B.V. All rights reserved.

[Postfire restoration of organic substance in the ground cover of the larch forests in the permafrost zone of central Evenkia].

Science.gov (United States)

Prokushkin, S G; Bogdanov, V V; Prokushkin, A S; Tokareva, I V

2011-01-01

The role of ground fires in transformation of organic substances in the ground cover of larch stands in the permafrost zone of Central Siberia was studied, as was the postfire restoration dynamics of organic substances. Ground fires lead to a considerable decrease in concentrations and resources of organic carbon and its individual fractions in the ground cover, and restoration takes many decades.

CITOGENETICS EFFECTS INDUCED BY THE ADMINISTRATION OF SUBSTANCES WITH REDUCTION POTENTIAL AT LARIX DECIDUA MILL. SSP. CARPATICA, PICEA ABIES (L. KARST. AND THUJA ORIENTALIS L

Directory of Open Access Journals (Sweden)

Ioana Anca Ieremia

2007-08-01

Full Text Available The paper present the influence of ascorbic acid, riboflavin, citric acid and sodium bisulphit upon the mitotic division of Larix decidua Mill ssp. carpatica, Picea abies (L. Karst and Thuja orientalis L. The treatment was applied in one variant, germinated seeds in ascorbic acid, riboflavin, citric acid and sodium bisulphit in 3 concentrations.

Amelioration and reforestation of sulfurous mine soils in Lusatia (eastern Germany)

International Nuclear Information System (INIS)

Katzur, J.; Haubold-Rosar, M.

1996-01-01

In Germany nearly 1.550 km 2 have been claimed by brown coal mining until now. Mine soils formed of carboniferous and sulfurous overburden are classified as sulfurous mine soils. They remain vegetation-free for decades and may be cultivated only after soil amelioration. The objective of amelioration is a sustained improvement of soil reaction. Lime requirement for the achievement of a certain pH-value is calculated from acid-base-balance (SBB). Lime fertilizers and base-rich brown coal ashes are used for amelioration. As ashes have several advantages, their application is recommended. The ameliorative application of lime fertilizer or brown coal ash should be incorporated intensively into the soil to a depth of 60 cm, better 100 cm. Amelioration includes a mineral fertilization with N, P and K. Afforestation with Pinus sylvestris, Pinus nigra, Larix decidua, Larix eurolepis. Tilia cordata, Quercus rubra and Quercus petraea on ameliorated mine soils show surprising good results. Multi-species stands have very positive effects on soil formation. Raw humus is formed under pine and larch, and under deciduous trees moder and mull with higher bioactivity and better development of water and nutrient balance in the topsoil are found. 55 refs., 6 figs., 4 tabs

The History of Tree and Shrub Taxa on Bol'shoy Lyakhovsky Island (New Siberian Archipelago since the Last Interglacial Uncovered by Sedimentary Ancient DNA and Pollen Data

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Heike H. Zimmermann

2017-10-01

Full Text Available Ecosystem boundaries, such as the Arctic-Boreal treeline, are strongly coupled with climate and were spatially highly dynamic during past glacial-interglacial cycles. Only a few studies cover vegetation changes since the last interglacial, as most of the former landscapes are inundated and difficult to access. Using pollen analysis and sedimentary ancient DNA (sedaDNA metabarcoding, we reveal vegetation changes on Bol’shoy Lyakhovsky Island since the last interglacial from permafrost sediments. Last interglacial samples depict high levels of floral diversity with the presence of trees (Larix, Picea, Populus and shrubs (Alnus, Betula, Ribes, Cornus, Saliceae on the currently treeless island. After the Last Glacial Maximum, Larix re-colonised the island but disappeared along with most shrub taxa. This was probably caused by Holocene sea-level rise, which led to increased oceanic conditions on the island. Additionally, we applied two newly developed larch-specific chloroplast markers to evaluate their potential for tracking past population dynamics from environmental samples. The novel markers were successfully re-sequenced and exhibited two variants of each marker in last interglacial samples. SedaDNA can track vegetation changes as well as genetic changes across geographic space through time and can improve our understanding of past processes that shape modern patterns.

Key mechanisms of metabolic changes in mountain pine and larch under drought in the Swiss National Park

Science.gov (United States)

Churakova, Olga; Bigler, Christof; Bryukhanova, Marina; Siegwolf, Rolf

2014-05-01

Forests are of great ecological, economic and social importance worldwide. In many regions they have been recently affected by water deficits during summer droughts due to increasing temperatures and shortage of precipitation (Allen et al. 2010). Climate models predict that drought frequency will continue to increase during the 21st century and beyond (CH 2011). Since the foundation of the Swiss National Park (SNP) in 1914 these forests have not been managed any more, which allows to study natural processes in these forest ecosystems. Since the 1990s, annual and spring temperatures increased in the SNP up to 0.5 ºC and 1.02 ºC, respectively, and average summer temperature increased up to 0.6 ºC. Annual precipitation decreased by 81 mm compared to the mean values (927 mm) from 1917 to 1989. Therefore, detailed studies of drought effects on the physiological functioning of trees over the last decades are needed. Recently, mortality processes of mountain pines were observed in the Swiss National Park (Bigler, Rigling 2013). It is of great interest to investigate and compare the physiological responses of mountain pine and larch to drought and to understand the mechanisms behind the mortality processes. The goal of our study is to investigate the key mechanisms of tree physiological responses to drought in the SNP using state-of-the-art methods of classical dendrochronology, tree physiology, stable isotope, and compound-specific isotope analyses. Long-term responses of mountain pine and larch trees from north- and south-facing sites to drought will be inferred from tree-ring width data. Based on climatic data a drought index will be calculated and reconstructed back in time. New chronologies for stable carbon and oxygen isotope ratios derived from both pine and larch tree-ring cellulose will provide retrospective insight into the long-term whole-plant physiological control of gas exchange derived from estimates of stomatal conductance, photosynthetic rate and

Fire Effects on Microbial Enzyme Activities in Larch Forests of the Siberian Arctic

Science.gov (United States)

Ludwig, S.; Alexander, H. D.; Bulygina, E. B.; Mann, P. J.; Natali, S.

2012-12-01

Arctic forest ecosystems are warming at an accelerated rate relative to lower latitudes, with global implications for C cycling within these regions. As climate continues to warm and dry, wildfire frequency and severity are predicted to increase, creating a positive feedback to climate warming. Increased fire activity will also influence the microenvironment experienced by soil microbes in disturbed soils. Because soil microbes regulate carbon (C) and nitrogen (N) cycling between terrestrial ecosystems and the atmosphere, it is important to understand microbial response to fires, particularly in the understudied larch forests in the Siberian Arctic. In this project, we created experimental burn plots in a mature larch forest in the Kolyma River watershed of Northeastern Siberia. Plots were burned at several treatments: control (no burn), low, moderate, and severe. After, 1 and 8 d post-fire, we measured soil organic layer depth, soil organic matter (SOM) content, soil moisture, and CO2 flux from the plots. Additionally, we leached soils and measured dissolved organic carbon (DOC), total dissolved nitrogen (TDN), NH4, NO3, soluble reactive phosphorus (SRP), and chromophoric dissolved organic matter (CDOM). Furthermore, we measured extracellular activity of four enzymes involved in soil C and nutrient cycling (leucine aminopeptidase (LAP), β-glucosidase, phosphatase, and phenol oxidase). One day post-fire, LAP activity was similarly low in all treatments, but by 8 d post-fire, LAP activity was lower in burned plots compared to control plots, likely due to increased nitrogen content with increasing burn severity. Phosphatase activity decreased with burn severity 1 d post-fire, but after 8 d, moderate and severe burn plots exhibited increased phosphatase activity. Coupled with trends in LAP activity, this suggests a switch in nutrient limitation from N to phosphorus that is more pronounced with burn severity. β-glucosidase activity similarly decreased with burn

Soil carbon accumulation and nitrogen retention traits of four tree species grown in common gardens

DEFF Research Database (Denmark)

Gurmesa, Geshere Abdisa; Schmidt, Inger Kappel; Gundersen, Per

2013-01-01

explored. Effects of four tree species on soil C and N stocks and soil water nitrate concentration below the root zone were evaluated in a common garden design replicated at eight sites in Denmark. The tree species were beech (Fagus sylvatica L.), oak (Quercus robur L.), larch (Larix leptolepis Kaempf......), and Norway spruce (Picea abies (L) Karst.). After four decades, there were significant differences in forest floor C stocks among all four species, and C stocks increased consistently in the order oak Forest floor N stocks only...... differed significantly between conifers and broadleaves. The observed differences in forest floor C and N stocks were attributed to differences in litter turnover rates among the tree species. Mineral soil C stocks were significantly higher in stands of Norway spruce than in stands of oak and beech while...

Process Optimization of Ultrasonic-Assisted Extraction of Arabinogalactan from Dihydroquercetin Extracted Residues by Response Surface Methodology and Evaluation of Its Antioxidant Activity

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Zaizhi Liu

2013-01-01

Full Text Available Ultrasound was used for the extraction of larch arabinogalactan from Larix gmelinii. The optimal conditions for ultrasound extraction were determined by response surface methodology. Specifically, the Box-Behnken design was employed to evaluate the effects of three independent variables: ultrasound time, temperature, and liquid-solid ratio. The highest arabinogalactan yield (11.18% was obtained under the optimal extraction condition (extraction temperature 41.5°C, extraction time 24.3 min, and liquid-solid ratio 40 mL/g. In addition, the antioxidant activity of arabinogalactan that was extracted from dihydroquercetin extraction residues exhibited a moderate and concentration-dependent hydroxyl radical-scavenging capacity, ferric-reducing power, and reducing power. The wood material was characterized before and after processing by scanning electron microscopy and Fourier-transform infrared spectroscopy.

Radionuclides in an arctic terrestrial ecosystem affected by atmospheric release from the Kraton-3 accidental underground nuclear explosion. 2001-2002

International Nuclear Information System (INIS)

Ramzaev, V.; Golikov, V.; Mishine, A.; Kaduka, M.; Burtcev, I.; Gedeonov, A.; Bulatenkov, Y.U.; Strand, P.; Brown, J.

2004-01-01

Current distributions of artificial radionuclides (ARN) were studied in the main compartments of a larch-tree forest lethally affected by a radioactive release from the Kraton-3 peaceful underground nuclear explosion (65.9 deg N, 112.3 deg E; Yakutia, Russia; 1978). Samples of soil, fungi, lichens, mosses, grasses, shrubs and trees were obtained at points belonging to four zones categorised by the severity of the ecosystem damage. Sampling was supplemented by dose rate measurements in air and mapping. The area of forest characterised by 100% lethality to adult larches (Larix gmelinii) and with partial, visually-detectable damage of other more radio-resistance species (e.g. lichens, mosses) covers a territory of approximately 1.2 km 2 . Elevated levels of long-lived ARN were found at all sampling sites. Maximum registered levels of the ground contamination with radionuclides of Cs, Sr and Pu were three orders of magnitude higher than those expected from global fallout. The ratios of 137 Cs to some other significant radionuclides in the ground contamination were as follows [mean (range)]: 90 Sr - 0.57(0.02-0.93); 239,240 Pu 44(25-72); 60 Co 470(220-760). Twenty-three years after a discrete contamination event, 90-95% of the total deposited radiocesium and plutonium has still remained in the lichen-moss on-ground cover and in the top 5 cm organic soil layer. At the same time, vertical and horizontal migrations of 90 Sr in soil were more pronounced. Strong surface contamination with 137 Cs, 90 Sr and plutonium was detected at the twigs and bark of the dead larches. The young larches that grew at the contaminated area following the initial destruction of the forest demonstrated a substantial ability to accumulate 137 Cs, 90 Sr and plutonium via roots, while the bushes selectively accumulated mainly radiostrontium. In contrast, some fungi concentrated mostly radiocesium. The levels of gamma dose rate in air and the environmental contamination with 137 Cs were found to

Tree ring δ18O reveals no long-term change of atmospheric water demand since 1800 in the northern Great Hinggan Mountains, China

Science.gov (United States)

Liu, Xiaohong; Zhang, Xuanwen; Zhao, Liangju; Xu, Guobao; Wang, Lixin; Sun, Weizhen; Zhang, Qiuliang; Wang, Wenzhi; Zeng, Xiaomin; Wu, Guoju

2017-07-01

Global warming will significantly increase transpirational water demand, which could dramatically affect plant physiology and carbon and water budgets. Tree ring δ18O is a potential index of the leaf-to-air vapor-pressure deficit (VPD) and therefore has great potential for long-term climatic reconstruction. Here we developed δ18O chronologies of two dominant native trees, Dahurian larch (Larix gmelinii Rupr.) and Mongolian pine (Pinus sylvestris var. mongolica), from a permafrost region in the Great Hinggan Mountains of northeastern China. We found that the July-August VPD and relative humidity were the dominant factors that controlled tree ring δ18O in the study region, indicating strong regulation of stomatal conductance. Based on the larch and pine tree ring δ18O chronologies, we developed a reliable summer (July-August) VPD reconstruction since 1800. Warming growing season temperatures increase transpiration and enrich cellulose 18O, but precipitation seemed to be the most important influence on VPD changes in this cold region. Periods with stronger transpirational demand occurred around the 1850s, from 1914 to 1925, and from 2005 to 2010. However, we found no overall long-term increasing or decreasing trends for VPD since 1800, suggesting that despite the increasing temperatures and thawing permafrost throughout the region, forest transpirational demand has not increased significantly during the past two centuries. Under current climatic conditions, VPD did not limit growth of larch and pine, even during extremely drought years. Our findings will support more realistic evaluations and reliable predictions of the potential influences of ongoing climatic change on carbon and water cycles and on forest dynamics in permafrost regions.

Life Cycle Analysis of Carbon Flow and Carbon Footprint of Harvested Wood Products of Larix principis-rupprechtii in China

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Fei Lun

2016-03-01

Full Text Available Larix principis-rupprechtii is a native tree species in North China with a large distribution; and its harvested timbers can be used for producing wood products. This study focused on estimating and comparing carbon flows and carbon footprints of different harvested wood products (HWPs from Larix principis-ruppechtii based on the life cycle analysis (from seedling cultivation to HWP final disposal. Based on our interviews and surveys, the system boundary in this study was divided into three processes: the forestry process, the manufacturing process, and the use and disposal process. By tracking carbon flows of HWPs along the entire life cycle, we found that, for one forest rotation period, a total of 26.81 tC/ha sequestered carbon was transferred into these HWPs, 66.2% of which were still stored in the HWP when the rotation period had ended; however, the HWP carbon storage decreased to 0.25 tC/ha (only 0.9% left in the 100th year after forest plantation. The manufacturing process contributed more than 90% of the total HWP carbon footprint, but it was still smaller than the HWP carbon storage. In terms of the carbon storage and the carbon footprint, construction products had the largest net positive carbon balance compared to furniture and panel products. In addition, HWP are known to have a positive impact on global carbon mitigation because they can store parts of the sequestered carbon for a certain period of time and they have a substitution effect on carbon mitigation. Furthermore, there still exist great opportunities for carbon mitigation from HWPs through the use of cleaner energy and increasing the utilization efficiency of wood fuel.

Effects of Thinning on the Spatial Structure of Larix principis-rupprechtii Plantation

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Shengxing Ye

2018-04-01

Full Text Available Structure-based forest management is a scientific and easy-to-operate method for sustainable forest management. We analyzed the stand spatial structure of Larix principis-rupprechtii plantation under five reserve densities. The results indicated that with the decrease of densities after thinning, the average mingling degree and uniform angle index had an increasing tendency, but the amplitude was small. Most of the trees were in zero mix, and a few of them were in moderate, strong, and relatively strong mix; the horizontal distribution patterns were uniform or near-uniform random. The distribution of neighborhood comparison and opening degree changed with a fluctuant pattern, but thinning decreased the competitive intensities to some extent. A composite structure index (Ci was established, based on the relative importance of the above four indicators, to evaluate the overall effect of thinning on stand structure characteristics. The findings showed that Ci increased with the increase of thinning intensity, that is, the stand spatial structure became more complex. This indicated that Ci may be a simple and rapid indicator to evaluate the overall effect of thinning on stand spatial structure within densities after thinning.

Growth decline linked to warming-induced water limitation in hemi-boreal forests.

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Wu, Xiuchen; Liu, Hongyan; Guo, Dali; Anenkhonov, Oleg A; Badmaeva, Natalya K; Sandanov, Denis V

2012-01-01

Hemi-boreal forests, which make up the transition from temperate deciduous forests to boreal forests in southern Siberia, have experienced significant warming without any accompanying increase in precipitation during the last 80 years. This climatic change could have a profound impact on tree growth and on the stability of forest ecosystems in this region, but at present evidence for these impacts is lacking. In this study, we report a recent dramatic decline in the growth of hemi-boreal forests, based on ring width measurements from three dominant tree-species (Pinus sylvestris, Larix sibirica and Larix gmelinii), sampled from eight sites in the region. We found that regional tree growth has become increasingly limited by low soil water content in the pre- and early-growing season (from October of the previous year to July of the current year) over the past 80 years. A warming-induced reduction in soil water content has also increased the climate sensitivity of these three tree species. Beginning in the mid-1980s, a clear decline in growth is evident for both the pine forests and the larch forests, although there are increasing trends in the proxy of soil water use efficiencies. Our findings are consistent with those from other parts of the world and provide valuable insights into the regional carbon cycle and vegetation dynamics, and should be useful for devising adaptive forest management strategies.

Tree-growth analyses to estimate tree species' drought tolerance.

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Eilmann, Britta; Rigling, Andreas

2012-02-01

Climate change is challenging forestry management and practices. Among other things, tree species with the ability to cope with more extreme climate conditions have to be identified. However, while environmental factors may severely limit tree growth or even cause tree death, assessing a tree species' potential for surviving future aggravated environmental conditions is rather demanding. The aim of this study was to find a tree-ring-based method suitable for identifying very drought-tolerant species, particularly potential substitute species for Scots pine (Pinus sylvestris L.) in Valais. In this inner-Alpine valley, Scots pine used to be the dominating species for dry forests, but today it suffers from high drought-induced mortality. We investigate the growth response of two native tree species, Scots pine and European larch (Larix decidua Mill.), and two non-native species, black pine (Pinus nigra Arnold) and Douglas fir (Pseudotsuga menziesii Mirb. var. menziesii), to drought. This involved analysing how the radial increment of these species responded to increasing water shortage (abandonment of irrigation) and to increasingly frequent drought years. Black pine and Douglas fir are able to cope with drought better than Scots pine and larch, as they show relatively high radial growth even after irrigation has been stopped and a plastic growth response to drought years. European larch does not seem to be able to cope with these dry conditions as it lacks the ability to recover from drought years. The analysis of trees' short-term response to extreme climate events seems to be the most promising and suitable method for detecting how tolerant a tree species is towards drought. However, combining all the methods used in this study provides a complete picture of how water shortage could limit species.

Early molecular events involved in Pinus pinaster Ait. somatic embryo development under reduced water availability: transcriptomic and proteomic analyses

Czech Academy of Sciences Publication Activity Database

Morel, A.; Teyssier, C.; Trontin, J.F.; Eliášová, Kateřina; Pešek, Bedřich; Beaufour, M.; Morabito, D.; Boizot, N.; Le Mette, C.; Belal-Bessai, L.; Vágner, Martin; Label, P.; Lelu-Walter, M.A.

2014-01-01

Roč. 152, č. 1 (2014), s. 184-201 ISSN 0031-9317 Institutional support: RVO:61389030 Keywords : GERMIN-LIKE PROTEIN * ABSCISIC-ACID * HYBRID LARCH Subject RIV: EF - Botanics Impact factor: 3.138, year: 2014

Complete mitochondrial genome of the larch hawk moth, Sphinx morio (Lepidoptera: Sphingidae).

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Kim, Min Jee; Choi, Sei-Woong; Kim, Iksoo

2013-12-01

The larch hawk moth, Sphinx morio, belongs to the lepidopteran family Sphingidae that has long been studied as a family of model insects in a diverse field. In this study, we describe the complete mitochondrial genome (mitogenome) sequences of the species in terms of general genomic features and characteristic short repetitive sequences found in the A + T-rich region. The 15,299-bp-long genome consisted of a typical set of genes (13 protein-coding genes, 2 rRNA genes, and 22 tRNA genes) and one major non-coding A + T-rich region, with the typical arrangement found in Lepidoptera. The 316-bp-long A + T-rich region located between srRNA and tRNA(Met) harbored the conserved sequence blocks that are typically found in lepidopteran insects. Additionally, the A + T-rich region of S. morio contained three characteristic repeat sequences that are rarely found in Lepidoptera: two identical 12-bp repeat, three identical 5-bp-long tandem repeat, and six nearly identical 5-6 bp long repeat sequences.

Exemplifying whole-plant ozone uptake in adult forest trees of contrasting species and site conditions

International Nuclear Information System (INIS)

Nunn, Angela J.; Wieser, Gerhard; Metzger, Ursula; Loew, Markus; Wipfler, Philip; Haeberle, Karl-Heinz; Matyssek, Rainer

2007-01-01

Whole-tree O 3 uptake was exemplified for Picea abies, Fagus sylvatica and Larix decidua in stands at high and low altitude and contrasting water availability through sap flow measurement in tree trunks, intrinsically accounting for drought and boundary layer effects on O 3 flux. O 3 uptake of evergreen spruce per unit foliage area was enhanced by 100% at high relative to low elevation, whereas deciduous beech and larch showed similar uptake regardless of altitude. The responsiveness of the canopy conductance to water vapor and, as a consequence, O 3 uptake to soil moisture and air humidity did not differ between species. Unifying findings at the whole-tree level will promote cause-effect based O 3 risk assessment and modeling. - Sap flow-based assessment of whole-tree O 3 uptake reflects similar responsiveness of canopy conductance and O 3 uptake across contrasting tree species and site conditions

Growth decline linked to warming-induced water limitation in hemi-boreal forests.

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Xiuchen Wu

Full Text Available Hemi-boreal forests, which make up the transition from temperate deciduous forests to boreal forests in southern Siberia, have experienced significant warming without any accompanying increase in precipitation during the last 80 years. This climatic change could have a profound impact on tree growth and on the stability of forest ecosystems in this region, but at present evidence for these impacts is lacking. In this study, we report a recent dramatic decline in the growth of hemi-boreal forests, based on ring width measurements from three dominant tree-species (Pinus sylvestris, Larix sibirica and Larix gmelinii, sampled from eight sites in the region. We found that regional tree growth has become increasingly limited by low soil water content in the pre- and early-growing season (from October of the previous year to July of the current year over the past 80 years. A warming-induced reduction in soil water content has also increased the climate sensitivity of these three tree species. Beginning in the mid-1980s, a clear decline in growth is evident for both the pine forests and the larch forests, although there are increasing trends in the proxy of soil water use efficiencies. Our findings are consistent with those from other parts of the world and provide valuable insights into the regional carbon cycle and vegetation dynamics, and should be useful for devising adaptive forest management strategies.

Climatic changes during the early Medieval and recent periods inferred from δ13C and δ18O of Siberian larch trees

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Sidorova, O. V.; Matthias Saurer, Rolf Siegwolf

2010-12-01

We report unique isotope datasets for δ13C and δ18O of wood and cellulose of larch trees (Larix cajanderi Mayr.) from Northeastern Yakutia [70°N-148°E] for the early Medieval (AD 900-1000) and recent (AD 1880-2004) periods. During the recent period June, July, and August air temperatures were positively correlated with δ13C and δ18O of wood and cellulose, while July precipitation was negatively correlated. The positive correlation with one of the warmest months (July) in Northeastern Yakutia could indicate high photosynthetic capacity, because warm and dry conditions cause stomatal closure and lower the isotopic fractionation, leading to less negative δ13C values. Because during July, the soil water is still frozen at a soil depth of 20-30 cm, the water accessibility for trees is limited, which can lead to drought situations. An increase in water availability allows for a higher stomatal conductance, resulting in lower δ13C values, leading to a negative relationship with summer precipitation. Furthermore, the vapor pressure deficit of July and August was significantly correlated with δ13C of wood and cellulose, indicating decreased stomatal conductance, an expression of moderate drought. This leads to reduced 13CO2 discrimination and less negative δ13C values. The simultaneous increase of δ18O also indicates a reduction in stomatal conductance under rather dry conditions or drought. Comparative analyses between mean isotope values for the AD 900-1000 and AD 1880-2004 periods indicate similar ranges of climatic conditions, with the exception of the period AD 1950-2004, which is characterized by increased summer drought. Whilst isotopic ratios in cellulose are reliably related to climatic variables, those in whole wood showed even stronger relationships during some periods. Strong positive correlations between δ18O of cellulose and Greenland ice-core data were detected for the beginning of the Medieval period (r=0.86; pdata, and gain a wider insight into

[Effects of compaction on diurnal variaaton of soil respiration in Larix gmellini plantation in summer].

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He, Na; Wang, Li-hai

2010-12-01

Taking the Larix gmellinii plantation in the experimental forest farm of Northeast Forestry University as test object, and by using Li-8100 automatic instrument, the daily CO2 emission rate of soil in summer under different degrees of man-made compaction was measured, with the regression models established. There were significant differences in the diurnal variation of soil respiration rate under different degrees of man-made compaction. In CK (no compaction), the maximum value of soil respiration appeared at 15:30-17:30, and the minimum value appeared at 03:30-05:30, which were obviously lagged behind those in compaction treatments. The maximum and minimum values of soil respiration rate in main roads appeared at 09:30-11:30 and 23:30-01:30, and those in branch roads appeared at 11:30 and 01:30-03:30, respectively. In all treatments, soil respiration rate had significant correlations with surface temperature, relative humidity, and the temperature at 10 cm soil depth, but the correlation with the soil moisture at 5 cm depth tended to be not significant when the compaction degree was increasing. Compaction altered surface soil physical structure, decreased surface soil CO2 release rate.

Influence of the Siberian larch extract on the processes of peroxide oxidation of lipids in experiment

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Pateyuk Andrey

2016-03-01

Full Text Available In modern conditions wood processing is one of the primary branches of production in Transbaikal region. In connection with big squares of logging the question of processing and utilizing waste products directly on the spot is particularly acute. We researched the activity of water extract from sawdust of Siberian larch "Ekstrapinus" on the power exchange and processes of peroxide oxidation of lipids against immobilized stress in experiment. The data provided in the article prove that the use of Ekstrapinus extract reduces the pathological violations arising under stress. So, Ekstrapinus extract restores energy potential of cages when modeling stress, restores energy potential of cells, normalizes balance in the system "peroxide oxidation of lipids – antioxidant protection" and supports the balance of tiol in an animal organism in the state of stress. Considering absence of toxicity in the recommended doses, it is possible to recommend their application under stress.

Diversity and community structure of ectomycorrhizal fungi associated with Larix chinensis across the alpine treeline ecotone of Taibai Mountain.

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Han, Qisheng; Huang, Jian; Long, Dongfeng; Wang, Xiaobing; Liu, Jianjun

2017-07-01

Alpine treeline ecotones represent ecosystems that are vulnerable to climate change. We investigated the ectomycorrhizal (ECM) community, which has potential to stabilize alpine ecosystems. ECM communities associated with Larix chinensis were studied in four zones along a natural ecotone from a mixed forest stand over pure forest stands, the timberline, and eventually, the treeline (3050-3450 m) in Tabai Mountain, China. Sixty operational taxonomic units (OTUs) of ECM fungi were identified by sequencing the rDNA internal transcribed spacer of ECM tips. The richness of ECM species increased with elevation. The soil C/N ratio was the most important factor explaining ECM species richness. The treeline zone harbored some unique ECM fungi whereas no unique genera were observed in the timberline and pure forest zone. Elevation and topography were equally important factors influencing ECM communities in the alpine region. We suggest that a higher diversity of the ECM fungal community associated with L. chinensis in the treeline zone could result from niche differentiation.

Facile Control of the Porous Structure of Larch-Derived Mesoporous Carbons via Self-Assembly for Supercapacitors

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Xin Zhao

2017-11-01

Full Text Available Mesoporous carbons have been successfully synthesized via self-assembly using larch-based resins as precursors and triblock copolymers as soft templates. The porous structure of mesoporous carbons can be tailored by adjusting the ratio of hydrophilic/hydrophobic (EO/PO units owing to interfacial curvature. Interestingly, the porous structures show a distinct change from vortex-like to worm-like pores, to stripe-like pores, and to ordered two-dimensional hexagonal pores as the ratio of hydrophilic/hydrophobic units increases, indicating the significant effect of EO/PO ratio on the porous structure. The mesoporous carbons as supercapacitor electrodes exhibit superior electrochemical capacitive performance and a high degree of reversibility after 2000 cycles for supercapacitors due to the well-defined mesoporosity of the carbon materials. Meanwhile, the superior carbon has a high specific capacitance of 107 F·g−1 in 6 M KOH at a current density of 10 A·g−1.

Soils of postpyrogenic larch stands in Central Siberia: Morphology, physicochemical properties, and specificity of soil organic matter

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Startsev, V. V.; Dymov, A. A.; Prokushkin, A. S.

2017-08-01

Morphological features, physicochemical properties, and specific characteristics of the organic matter of cryozems (Cryosols) under postpyrogenic larch forests affected by fires 2, 6, 22, 55, and 116 years ago are considered. The morphological changes in the soils affected by fires are manifested by the burning of the upper organic horizons with preservation of pyrogenic features in the soils for more than a century after the fire. In the first years (2 and 6 years) after the fire, the acidity of the organic horizons and their base saturation become lower. The postpyrogenic soils are characterized by the smaller contribution of the organic horizons to the total pools of soil organic carbon. In the studied cryozems, the organic carbon content is correlated with the contents of oxalate-extractable iron and aluminum. A decrease in the content of water-soluble organic compounds in the soils is observed after the fires; gradually, their content increases upon restoration of the ground cover.

Terpenoid emissions from fully grown east Siberian Larix cajanderi trees

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M. K. Kajos

2013-07-01

Full Text Available While emissions of many biogenic volatile organic compounds (BVOCs, such as terpenoids, have been studied quite intensively in North American and Scandinavian boreal forests, the vast Siberian boreal forests have remained largely unexplored by experimental emission studies. In this study the shoot-scale terpenoid emission rates from two mature Larix cajanderi trees growing in their natural habitat in eastern Siberia were measured at the Spasskaya Pad flux measurement site (62°15´18.4" N, 129°37´07.9" E located on the western bank of the Lena river. The measurements were conducted during three campaigns: 3–24 June, 8–26 July, and 14–30 August, in the summer of 2009. A dynamic flow-through enclosure technique was applied for adsorbent sampling, and the samples were analysed offline with a gas chromatograph. Between 29 and 45 samples were taken from each shoot during all three campaigns. Seven different monoterpenes, six different sesquiterpenes, linalool isoprene, and 2-methyl-3-buten-2-ol (MBO were identified. The monthly median value of the total terpenoid emissions varied between 0.006 and 10.6 μg gdw−1 h−1. The emissions were dominated by monoterpenes, which constituted between 61 and 92% of the total emissions. About half of the monoterpene emissions were comprised of Δ 3-carene; α- and β-pinene had significant emissions as well. Linalool emissions were also substantial, comprising 3–37% of the total emissions, especially in June. Sesquiterpenes accounted for less than 3% and isoprene less than 1% of the total emissions. Based on the measured emission rates, the relative atmospheric concentration of each compound was estimated. Monoterpenes were the species with the highest relative concentration, while linalool and sesquiterpenes had a notably smaller contribution to the estimated atmospheric concentration than to the emission rates. A temperature-dependent pool algorithm with a constant β (0.09 °C−1 for monoterpenes

Fire Effects on Microbial Dynamics and C, N, and P Cycling in Larch Forests of the Siberian Arctic

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Ludwig, S.; Alexander, H. D.; Mann, P. J.; Natali, S.; Schade, J. D.

2013-12-01

Arctic forest ecosystems are warming at an accelerated rate relative to lower latitudes, with global implications for C cycling within these regions. As climate continues to warm and dry, wildfire frequency and severity are predicted to increase, creating a positive feedback to climate warming. Because soil microbes regulate carbon (C) and nitrogen (N) cycling between terrestrial ecosystems and the atmosphere, it is important to understand microbial response to fires, particularly in the understudied larch forests in the Siberian Arctic. In this project, we created experimental burn plots in a mature larch forest in the Kolyma River watershed of Northeastern Siberia. Plots were burned at several treatments: control (no burn), low, moderate, and severe. After 1 day, 8 days and 1 year post-fire, we measured CO2 flux from the plots, and measured dissolved organic carbon (DOC), total dissolved nitrogen (TDN), NH4, NO3, PO4, and chromophoric dissolved organic matter (CDOM) from soil leachates. Furthermore, we measured extracellular activity of four enzymes involved in soil C and nutrient cycling (leucine aminopeptidase (LAP), β-glucosidase, phosphatase, and phenol oxidase). Both 1 day and 8 days post-fire DOC, TDN, NH4, and PO4 all increased with burn severity, but by 1 year they were similar to control plots. The aromaticity and molecular weight of DOM decreased with fire severity. One day post-fire we observed a spike in phenol oxidase activity in the severe burns only, and a decline in β-glucosidase and phosphatase activity. By 8 days post-fire all enzyme activities were at the level of the control plots. 1 year post-fire LAP, β-glucosidase, and phosphatase all decreased with fire severity, parallel to a decrease in CO2 flux by fire severity. Ratios of enzymatic activity 1 year post-fire reflect a switch of resource allocation from P acquiring to N acquiring activities in more severe fires. Our results show an immediate microbial response to the short-term effects

Climate-Induced Landsliding within the Larch Dominant Permafrost Zone of Central Siberia

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Kharuk, Viacheslav I.; Shushpanov, Alexandr S.; Im, Sergei T.; Ranson, Kenneth J.

2016-01-01

Climate impact on landslide occurrence and spatial patterns were analyzed within the larch-dominant communities associated with continuous permafrost areas of central Siberia. We used high resolution satellite imagery (i.e. QuickBird, WorldView) to identify landslide scars over an area of 62 000 km2. Landslide occurrence was analyzed with respect to climate variables (air temperature, precipitation, drought index SPEI), and Gravity Recovery and Climate Experiment satellite derived equivalent of water thickness anomalies (EWTA). Landslides were found only on southward facing slopes, and the occurrence of landslides increased exponentially with increasing slope steepness. Lengths of landslides correlated positively with slope steepness. The observed upper elevation limit of landslides tended to coincide with the tree line. Observations revealed landslides occurrence was also found to be strongly correlated with August precipitation (r = 0.81) and drought index (r = 0.7), with June-July-August soil water anomalies (i.e., EWTA, r = 0.68-0.7), and number of thawing days (i.e., a number of days with t (max) > 0 deg C; r = 0.67). A significant increase in the variance of soil water anomalies was observed, indicating that occurrence of landslides may increase even with a stable mean precipitation level. The key-findings of this study are (1) landslides occurrence increased within the permafrost zone of central Siberia in the beginning of the 21st century; (2) the main cause of increased landslides occurrence are extremes in precipitation and soil water anomalies; and (3) landslides occurrence are strongly dependent on relief features such as southward facing steep slopes.

Long-term measurement of terpenoid flux above a Larix kaempferi forest using a relaxed eddy accumulation method

Science.gov (United States)

Mochizuki, Tomoki; Tani, Akira; Takahashi, Yoshiyuki; Saigusa, Nobuko; Ueyama, Masahito

2014-02-01

Terpenoids emitted from forests contribute to the formation of secondary organic aerosols and affect the carbon budgets of forest ecosystems. To investigate seasonal variation in terpenoid flux involved in the aerosol formation and carbon budget, we measured the terpenoid flux of a Larix kaempferi forest between May 2011 and May 2012 by using a relaxed eddy accumulation method. Isoprene was emitted from a fern plant species Dryopteris crassirhizoma on the forest floor and monoterpenes from the L. kaempferi. α-Pinene was the dominant compound, but seasonal variation of the monoterpene composition was observed. High isoprene and monoterpene fluxes were observed in July and August. The total monoterpene flux was dependent on temperature, but several unusual high positive fluxes were observed after rain fall events. We found a good correlation between total monoterpene flux and volumetric soil water content (r = 0.88), and used this correlation to estimate monoterpene flux after rain events and calculate annual terpenoid emissions. Annual carbon emission in the form of total monoterpenes plus isoprene was determined to be 0.93% of the net ecosystem exchange. If we do not consider the effect of rain fall, carbon emissions may be underestimated by about 50%. Our results suggest that moisture conditions in the forest soil is a key factor controlling the monoterpene emissions from the forest ecosystem.

Using Field Data and GIS-Derived Variables to Model Occurrence of Williamson's Sapsucker Nesting Habitat at Multiple Spatial Scales.

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Mark C Drever

Full Text Available Williamson's sapsucker (Sphyrapicus thyroideus is a migratory woodpecker that breeds in mixed coniferous forests in western North America. In Canada, the range of this woodpecker is restricted to three small populations in southern British Columbia, precipitating a national listing as 'Endangered' in 2005, and the need to characterize critical habitat for its survival and recovery. We compared habitat attributes between Williamson's sapsucker nest territories and random points without nests or detections of this sapsucker as part of a resource selection analysis to identify the habitat features that best explain the probability of nest occurrence in two separate geographic regions in British Columbia. We compared the relative explanatory power of generalized linear models based on field-derived and Geographic Information System (GIS data within both a 225 m and 800 m radius of a nest or random point. The model based on field-derived variables explained the most variation in nest occurrence in the Okanagan-East Kootenay Region, whereas nest occurrence was best explained by GIS information at the 800 m scale in the Western Region. Probability of nest occurrence was strongly tied to densities of potential nest trees, which included open forests with very large (diameter at breast height, DBH, ≥57.5 cm western larch (Larix occidentalis trees in the Okanagan-East Kootenay Region, and very large ponderosa pine (Pinus ponderosa and large (DBH 17.5-57.5 cm trembling aspen (Populus tremuloides trees in the Western Region. Our results have the potential to guide identification and protection of critical habitat as required by the Species at Risk Act in Canada, and to better manage Williamson's sapsucker habitat overall in North America. In particular, management should focus on the maintenance and recruitment of very large western larch and ponderosa pine trees.

Plant hydraulic strategies and their variability at high latitudes: insights from a southern Canadian boreal forest site

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Pappas, C.; Matheny, A. M.; Maillet, J.; Baltzer, J. L.; Stephens, J.; Barr, A.; Black, T. A.; Sonnentag, O.

2016-12-01

Boreal forests cover about one third of the world's forested area with a large part of the boreal zone located in Canada. These high-latitude ecosystems respond rapidly to environmental changes. Plant water stress and the resulting drought-induced mortality has been recently hypothesised as a major driver of forest changes in western Canada. Although boreal forests often exhibit low floristic complexity, local scale abiotic heterogeneities may lead to highly variable plant functional traits and thus to diverging plant responses to environmental changes. However, detailed measurements of plant hydraulic strategies and their inter- and intra-specific variability are still lacking for these ecosystems. Here, we quantify plant water use and hydraulic strategies of black spruce (Picea mariana) and larch (Larix laricina), that are widespread in the boreal zone, at a long-term monitoring site located in central Saskatchewan (53.99° N, 105.12° W; elevation 628.94 m a.s.l.). The site is characterized by a mature black spruce overstorey that dominates the landscape with few larch individuals. The ground cover consists mainly of mosses with some peat moss and lichens over a rich soil organic layer. Tree-level sap flux density, measured with Granier-style thermal dissipation probes (N=39), and concurrently recorded radial stem dynamics, measured with high frequency dendrometers (N=13), are used to quantify plant hydraulic functioning during the 2016 growing season. Hydrometeorological measurements, including soil moisture and micrometeorological data, are used to describe environmental constraints in plant water use. Tree-level dynamics are then integrated to the landscape and compared with ecosystem-level evapotranspiration measurements from an adjacent eddy-covariance flux tower. This experimental design allows us to quantify the main environmental drivers that shape plant hydraulic strategies in this southern boreal zone and to provide new insights into the inter- and

[Effect of soil phenolic acids on soil microbe of coal-mining depressed land after afforestation restoration by different tree species].

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Ji, Li; Yang, Li Xue

2017-12-01

Phenolic acids are one of the most important factors that influence microbial community structure. Investigating the dynamic changes of phenolic acids and their relationship with the microbial community structure in plantation soils with different tree species could contribute to better understanding and revealing the mechanisms of microbial community changes under afforestation restoration in coal-mining subsidence areas. In this study, plantations of three conifer and one deciduous species (Pinus koraiensis, Larix gmelinii, Pinus sylvestris var. mongolica, and Populus ussuriensis) were established on abandoned coal-mining subsidence areas in Baoshan District, Shuangyashan City. The contents of soil phenols, 11 types of phenolic acids, and microbial communities in all plots were determined. The results showed that the contents of soil complex phenol in plantations were significantly higher than that of abandoned land overall. Specifically, soils in larch and poplar plantations had higher contents of complex phenol, while soils in larch and Korean pine plantations had greater contents of total phenol. Moreover, soil in the P. koraiensis plantation had a higher content of water-soluble phenol compared with abandoned lands. The determination of 11 phenolic acids indicated that the contents of ferulic acid, abietic acid, β-sitosterol, oleanolic acid, shikimic acid, linoleic acid, and stearic acid were higher in plantation soils. Although soil phenol contents were not related with soil microbial biomass, the individual phenolic acids showed a significant relationship with soil microbes. Ferulic acid, abietic acid, and β-sitosterol showed significant promoting effects on soil microbial biomass, and they showed positive correlations with fungi and fungi/bacteria ratio. These three phenolic acids had higher contents in the poplar plantation, suggesting that poplar affo-restation had a beneficial effect on soil quality in coal-mining subsidence areas.

Using Field Data and GIS-Derived Variables to Model Occurrence of Williamson's Sapsucker Nesting Habitat at Multiple Spatial Scales.

Science.gov (United States)

Drever, Mark C; Gyug, Les W; Nielsen, Jennifer; Stuart-Smith, A Kari; Ohanjanian, I Penny; Martin, Kathy

2015-01-01

Williamson's sapsucker (Sphyrapicus thyroideus) is a migratory woodpecker that breeds in mixed coniferous forests in western North America. In Canada, the range of this woodpecker is restricted to three small populations in southern British Columbia, precipitating a national listing as 'Endangered' in 2005, and the need to characterize critical habitat for its survival and recovery. We compared habitat attributes between Williamson's sapsucker nest territories and random points without nests or detections of this sapsucker as part of a resource selection analysis to identify the habitat features that best explain the probability of nest occurrence in two separate geographic regions in British Columbia. We compared the relative explanatory power of generalized linear models based on field-derived and Geographic Information System (GIS) data within both a 225 m and 800 m radius of a nest or random point. The model based on field-derived variables explained the most variation in nest occurrence in the Okanagan-East Kootenay Region, whereas nest occurrence was best explained by GIS information at the 800 m scale in the Western Region. Probability of nest occurrence was strongly tied to densities of potential nest trees, which included open forests with very large (diameter at breast height, DBH, ≥57.5 cm) western larch (Larix occidentalis) trees in the Okanagan-East Kootenay Region, and very large ponderosa pine (Pinus ponderosa) and large (DBH 17.5-57.5 cm) trembling aspen (Populus tremuloides) trees in the Western Region. Our results have the potential to guide identification and protection of critical habitat as required by the Species at Risk Act in Canada, and to better manage Williamson's sapsucker habitat overall in North America. In particular, management should focus on the maintenance and recruitment of very large western larch and ponderosa pine trees.

Hydraulic properties and fine root mass of Larix sibirica along forest edge-interior gradients

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Chenlemuge, Tselmeg; Dulamsuren, Choimaa; Hertel, Dietrich; Schuldt, Bernhard; Leuschner, Christoph; Hauck, Markus

2015-02-01

At its southernmost distribution limit in Inner Asia, the boreal forest disintegrates into forest fragments on moist sites (e.g. north-facing slopes), which are embedded in grasslands. This landscape mosaic is characterized by a much higher forest edge-to-interior ratio than in closed boreal forests. Earlier work in the forest-steppe ecotone of Mongolia has shown that Larix sibirica trees at forest edges grow faster than in the forest interior, as the more xeric environment at the edge promotes self-thinning and edges are preferentially targeted by selective logging and livestock grazing. Lowered stand density reduces competition for water in these semi-arid forests, where productivity is usually limited by summer drought. We studied how branch and coarse root hydraulic architecture and xylem conductivity, fine root biomass and necromass, and fine root morphology of L. sibirica respond to sites differing in water availability. Studying forest edge-interior gradients in two regions of western Mongolia, we found a significant reduction of branch theoretical (Kp) and empirical conductivity (Ks) in the putatively more drought-affected forest interior in the Mongolian Altai (mean precipitation: 120 mm yr-1), while no branch xylem modification occurred in the moister Khangai Mountains (215 mm yr-1). Kp and Ks were several times larger in roots than in branches, but root hydraulics were not influenced by stand density or mean annual precipitation. Very low fine root biomass: necromass ratios at all sites, and in the forest interior in particular, suggest that L. sibirica seeks to maintain a relatively high root conductivity by producing large conduits, which results in high root mortality due to embolism during drought. Our results suggest that L. sibirica is adapted to the semi-arid climate at its southernmost distribution limit by considerable plasticity of the branch hydraulic system and a small but apparently dynamic fine root system.

Environmental control of CO2-assimilation and leaf conductance in Larix decidua Mill. : I. A comparison of contrasting natural environments.

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Benecke, U; Schulze, E -D; Matyssek, R; Havranek, W M

1981-08-01

CO 2 -assimilation and leaf conductance of Larix decidua Mill. were measured in the field at high (Patscherkofel, Austria) and low (Bayreuth, Germany) elevation in Europe, and outside its natural range along an altitudinal gradient in New Zealand.Phenology of leaf and stem growth showed New Zealand sites to have much longer growing seasons than in Europe, so that the timberline (1,330 m) season was almost twice as long as at the Austrian timberline (1,950 m).The maximum rates of photosynthesis, A max , were similar at all sites after completion of leaf growth, namely 3 to 3.5 μmol m -2 s -1 . Only the sun needles of the Bayreuth tree reached 3.5 to 5 μmol m -2 s -1 . Light response curves for CO 2 -assimilation changed during leaf ontogeny, the slope being less in young than in adult leaves. The temperature optimum for 90% of maximum photosynthesis was at all sites similar between ca. 12-28°C for much of the summer. Only at the cooler high altitude timberline sites were optima lower at ca. 10-16°C in developing needles during early summer.A linear correlation existed between A max and leaf conductance at A max , and this showed no difference between the sites except for sun needles at Bayreuth.Leaf conductance responded strongly to light intensity and this was concurrent with the light response of CO 2 -uptake. A short-term and a long-term effect were differentiated. With increasing age maximum rates of CO 2 -uptake and leaf conductance at A max increased, whereas short-term response during changes in light declined. The stomata became less responsive with increasing age and tended to remain open. The stomatal responses to light have a significant effect on the water use efficiency during diurnal courses. A higher water use efficiency was found for similar atmospheric conditions in spring than in autumn.Stomata responded with progressive closure to declining air humidity in a similar manner under dissimilar climates. Humidity response thus showed insensitivity

[Parameter sensitivity of simulating net primary productivity of Larix olgensis forest based on BIOME-BGC model].

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He, Li-hong; Wang, Hai-yan; Lei, Xiang-dong

2016-02-01

Model based on vegetation ecophysiological process contains many parameters, and reasonable parameter values will greatly improve simulation ability. Sensitivity analysis, as an important method to screen out the sensitive parameters, can comprehensively analyze how model parameters affect the simulation results. In this paper, we conducted parameter sensitivity analysis of BIOME-BGC model with a case study of simulating net primary productivity (NPP) of Larix olgensis forest in Wangqing, Jilin Province. First, with the contrastive analysis between field measurement data and the simulation results, we tested the BIOME-BGC model' s capability of simulating the NPP of L. olgensis forest. Then, Morris and EFAST sensitivity methods were used to screen the sensitive parameters that had strong influence on NPP. On this basis, we also quantitatively estimated the sensitivity of the screened parameters, and calculated the global, the first-order and the second-order sensitivity indices. The results showed that the BIOME-BGC model could well simulate the NPP of L. olgensis forest in the sample plot. The Morris sensitivity method provided a reliable parameter sensitivity analysis result under the condition of a relatively small sample size. The EFAST sensitivity method could quantitatively measure the impact of simulation result of a single parameter as well as the interaction between the parameters in BIOME-BGC model. The influential sensitive parameters for L. olgensis forest NPP were new stem carbon to new leaf carbon allocation and leaf carbon to nitrogen ratio, the effect of their interaction was significantly greater than the other parameter' teraction effect.

[Effects of mushroom residue compost on growth and nutrient accumulation of Larix principis-rupprechtii containerized transplants].

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Teng, Fei; Liu, Yong; Lou, Jun Shan; Sun, Qiao Yu; Wan, Fang Fang; Yang, Chen; Zhang, Jin

2016-12-01

Excessive use of peat may cause some environmental problems. To alleviate the negative effect, an experiment was conducted with the mushroom residue compost to replace peat in Larix principis-rupprechtii containerized transplant production, and the proportion of mushroom residue compost was 0% (T 0 , control), 15% (T 1 ), 18.75% (T 2 ), 25% (T 3 ), 37.50% (T 4 ), 50% (T 5 ), 56.25% (T 6 ) and 60% (T 7 ), respectively. The physical and chemical features of the substrates and its effect on the vegetative growth and nutrient accumulation of L. principis-rupprechtii containerized transplants were studied. The results showed when the proportion of mushroom residue compost in the substrate accounted for 50% or less, there was no significant difference in the transplant height, diameter, and biomass compared with the control, and the nutrient concentration in T 2 , T 4 , T 5 treatments was significantly higher than in T 0 . The pH value was sub-acidic to neutral which was suitable to the transplant growth. When the compost proportion accounted for more than 50%, the pH value was altered to alkali and was not suitable to the transplant growth. When the proportion of mushroom residue compost accounted for 15%, the plant grew best, and the height, diameter, and total biomass got the highest. Therefore, using mushroom residue compost to replace peat in L. principis-rupprechtii containerized transplants cultivation was feasible and the maximum replacement ratio could reach 50%. The high quality transplants could be obtained when the compost replacement ratio was 15%.

Preliminary evaluation of the potential of tree-ring cellulose content as a novel supplementary proxy in dendroclimatology

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Ziehmer, Malin M.; Nicolussi, Kurt; Schlüchter, Christian; Leuenberger, Markus

2018-02-01

Cellulose content (CC (%)) in tree rings is usually utilised as a tool to control the quality of the α-cellulose extraction from tree rings in the preparation of stable-isotope analysis in wooden tissues. Reported amounts of CC (%) are often limited to mean values per tree. For the first time, CC (%) series from two high-Alpine species, Larix decidua Mill. (European Larch, LADE) and Pinus cembra L. (Swiss stone pine, PICE) are investigated in modern wood samples and Holocene wood remains from the Early and mid-Holocene. Modern CC (%) series reveal a species-specific low-frequency trend independent of their sampling site over the past 150 years. Climate-cellulose relationships illustrate the ability of CC (%) to record temperature in both species but for slightly different periods within the growing season. The Holocene CC (%) series illustrate diverging low-frequency trends in both species, independent of sampling site characteristics (latitude, longitude and elevation). Moreover, potential age trends are not apparent in the two coniferous species. The arithmetic mean of CC (%) series in the Early and mid-Holocene indicate low CC (%) succeeding cold events. In conclusion, CC (%) in tree rings show high potential to be established as novel supplementary proxy in dendroclimatology.

Dynamics at the treeline: differential responses of Picea mariana and Larix laricina to climate change in eastern subarctic Québec

International Nuclear Information System (INIS)

Dufour-Tremblay, Geneviève; Boudreau, Stéphane; Lévesque, Esther

2012-01-01

Treelines are known to be temperature-sensitive ecotones, and therefore could rapidly expand their range limits in response to climate warming. Observations of lack of range expansion, however, indicate that ecological constraints partly control the treeline ecotones. The main objectives of this study were to evaluate Picea mariana and Larix laricina recruitment and growth at and above the altitudinal treeline of Kangiqsualujjuaq (Nunavik), where warmer temperatures since the 1990s have already triggered shrub expansion. We mapped, harvested, dated and measured tree individuals along two altitudinal gradients from the forested stands below the treeline to hilltops. Since the 1990s, a pulse of L. laricina seedling establishment has occurred at and above the treeline. Dendrochronological analysis revealed that L. laricina underwent a rapid vertical growth and radial growth that accelerated from the 1990s. No recruitment was observed for P. mariana in response to the regional warming, suggesting a regeneration failure of this species. Our results indicated that the L. laricina colonization below and above the treeline in recent decades in response to the regional warming should modify the landscape physiognomy of the study area in the near future. (letter)

Larix laricina, an Antidiabetic Alternative Treatment from the Cree of Northern Quebec Pharmacopoeia, Decreases Glycemia and Improves Insulin Sensitivity In Vivo

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Despina Harbilas

2012-01-01

Full Text Available Larix laricina K. Koch is a medicinal plant belonging to traditional pharmacopoeia of the Cree of Eeyou Istchee (Eastern James Bay area of Canada. In vitro screening studies revealed that, like metformin and rosiglitazone, it increases glucose uptake and adipogenesis, activates AMPK, and uncouples mitochondrial function. The objective of this study was to evaluate the antidiabetic and antiobesity potential of L. laricina in diet-induced obese (DIO C57BL/6 mice. Mice were subjected for eight or sixteen weeks to a high fat diet (HFD or HFD to which L. laricina was incorporated at 125 and 250 mg/kg either at onset (prevention study or in the last 8 of the 16 weeks of administration of the HFD (treatment study. L. laricina effectively decreased glycemia levels, improved insulin resistance, and slightly decreased abdominal fat pad and body weights. This occurred in conjunction with increased energy expenditure as demonstrated by elevated skin temperature in the prevention study and improved mitochondrial function and ATP synthesis in the treatment protocol. L. laricina is thus a promising alternative and complementary therapeutic approach for the treatment and care of obesity and diabetes among the Cree.

Extreme fire events are related to previous-year surface moisture conditions in permafrost-underlain larch forests of Siberia

International Nuclear Information System (INIS)

Forkel, Matthias; Beer, Christian; Thonicke, Kirsten; Cramer, Wolfgang; Bartalev, Sergey; Schmullius, Christiane

2012-01-01

Wildfires are a natural and important element in the functioning of boreal forests. However, in some years, fires with extreme spread and severity occur. Such severe fires can degrade the forest, affect human values, emit huge amounts of carbon and aerosols and alter the land surface albedo. Usually, wind, slope and dry air conditions have been recognized as factors determining fire spread. Here we identify surface moisture as an additional important driving factor for the evolution of extreme fire events in the Baikal region. An area of 127 000 km 2 burned in this region in 2003, a large part of it in regions underlain by permafrost. Analyses of satellite data for 2002–2009 indicate that previous-summer surface moisture is a better predictor for burned area than precipitation anomalies or fire weather indices for larch forests with continuous permafrost. Our analysis advances the understanding of complex interactions between the atmosphere, vegetation and soil, and how coupled mechanisms can lead to extreme events. These findings emphasize the importance of a mechanistic coupling of soil thermodynamics, hydrology, vegetation functioning, and fire activity in Earth system models for projecting climate change impacts over the next century. (letter)

Soil CO2 efflux of a larch forest in northern Japan

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Y. Fujinuma

2010-11-01

Full Text Available We had continuously measured soil CO2 efflux (Rs in a larch forest in northern Japan at hourly intervals for the snow-free period in 2003 with an automated chamber system and partitioned Rs into heterotrophic respiration (Rh and autotrophic respiration (Rr by using the trench method. In addition, we applied the soil CO2 concentration gradients method to continuously measure soil CO2 profiles under snowpack in the snowy period and to partition Rs into topsoil (Oa and A horizons CO2 efflux (Ft with a depth of 0.13 m and sub-soil (C horizon CO2 efflux (Fc. We found that soil CO2 effluxes were strongly affected by the seasonal variation of soil temperature but weakly correlated with soil moisture, probably because the volumetric soil moisture (30–40% at 95% confidence interval was within a plateau region for root and microbial activities. The soil CO2 effluxes changed seasonally in parallel with soil temperature in topsoil with the peak in late summer. On the other hand, the contribution of Rr to Rs was the largest at about 50% in early summer, when canopy photosynthesis and plant growth were more active. The temperature sensitivity (Q10 of Rr peaked in June. Under snowpack, Rs was stable until mid-March and then gradually increased with snow melting. Rs summed up to 79 gC m−2 during the snowy season for 4 months. The annual Rs was determined at 934 gC m−2 y−1 in 2003, which accounted for 63% of ecosystem respiration. The annual contributions of Rh and Rs to Rs were 57% and 43%, respectively. Based on the gradient approach, Rs was partitioned vertically into litter (Oi and Oe horizons with a depth of 0.01–0.02 m, topsoil and sub-soil respirations with proportions of 6, 72 and 22%, respectively, on an annual basis. The vertical distribution of CO2 efflux was consistent with those of soil carbon and root biomass.

Ultrasound-assisted extraction of arabinogalactan and dihydroquercetin simultaneously from Larix gmelinii as a pretreatment for pulping and papermaking.

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Chunhui Ma

Full Text Available An ultrasound-assisted extraction (UAE method using ethanol was applied for extracting arabinogalactan (AG and dihydroquercetin (DHQ simultaneously from larch wood, as a pretreatment for pulping and papermaking. The extraction parameters were optimized by a Box-Behnken experimental design with the yields of AG and DHQ as the response values. Under optimum conditions (three extractions, each using 40% ethanol, for 50 min, 200 W ultrasound power and 1∶18 solid-liquid ratio, the yields of AG and DHQ were 183.4 and 36.76 mg/g, respectively. After UAE pretreated, the wood chips were used for Kraft pulping (KP and high boiling solvent pulping (HBSP. The pulping yield after pretreatment was higher than that of untreated (the pulping yields of untreated HBSP and KP were 42.37% and 39.60%, and the pulping yields of HBSP and KP after UAE-pretreated were 44.23% and 41.50% respectively, as indicated by a lower kappa number (77.91 and 27.30 for untreated HBSP and KP; 77.01 and 26.83 for UAE-pretreated HBSP and KP. Furthermore, the characteristics of paper produced from pretreated wood chips were superior to those from the untreated chips: the basis weight was lower (85.67 and 82.48 g·cm(-2 for paper from untreated KP and HBSP; 79.94 and 80.25 g·cm(-2 for paper from UAE-pretreated KP and HBSP, and the tensile strengths, tearing strengths, bursting strengths, and folding strengths were higher than these of paper after UAE-pretreated, respectively.

CO2 enrichment alters diurnal stem radius fluctuations of 36-yr-old Larix decidua growing at the alpine tree line.

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Dawes, Melissa A; Zweifel, Roman; Dawes, Nicholas; Rixen, Christian; Hagedorn, Frank

2014-06-01

To understand how trees at high elevations might use water differently in the future, we investigated the effects of CO2 enrichment and soil warming (separately and combined) on the water relations of Larix decidua growing at the tree line in the Swiss Alps. We assessed diurnal stem radius fluctuations using point dendrometers and applied a hydraulic plant model using microclimate and soil water potential data as inputs. Trees exposed to CO2 enrichment for 9 yr showed smaller diurnal stem radius contractions (by 46 ± 16%) and expansions (42 ± 16%) compared with trees exposed to ambient CO2 . Additionally, there was a delay in the timing of daily maximum (40 ± 12 min) and minimum (63 ± 14 min) radius values for trees growing under elevated CO2 . Parameters optimized with the hydraulic model suggested that CO2 -enriched trees had an increased flow resistance between the xylem and bark, representing a more buffered water supply system. Soil warming did not alter diurnal fluctuation dynamics or the CO2 response. Elevated CO2 altered the hydraulic water flow and storage system within L. decidua trees, which might have contributed to enhanced growth during 9 yr of CO2 enrichment and could ultimately influence the future competitive ability of this key tree-line species. © 2014 WSL Institute for Snow and Avalanche Research - SLF. New Phytologist © 2014 New Phytologist Trust.

GC/MS Analysis of Oil Extractives from Wood and Bark of Pinus sylvestris, Abies alba, Picea abies, and Larix decidua

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Mohamed Zidan Mohamed Salem

2015-09-01

Full Text Available Wood and bark oil extractives components (OECs of Pinus sylvestris, Abies alba, Picea abies, and Larix decidua grown in the Czech Republic were analyzed using gas chromatography/ mass spectrometry (GC/MS. The analysis showed the presence of monoterpene, sesquiterpene, diterpenoids, and resin acids. The highest percentages of OECs in the wood of P. sylvestris were α-fenchyl alcohol (26.04%, D-fenchyl alcohol (12.39%, and L-borneol (8.81%; the OECs in the bark included α-methyl-γ-butyrolactone (31.88% and isodecyl octyl phthalate (15.85%. The most frequently occurring OEC in A. alba wood were 4-hydroxy-4-methyl-2-pentanone (73.36%, α-cedrol (10.08%, and 2,6-dimethyl-1,3,6-heptatriene (7.35%; the most OECs in the bark were di(2-ethylhexylphthalate (59.83%, methyl cyclopentane (16.63%, and 13-epimanool (6.31%. P. abies wood OECs included 4-hydroxy-4-methyl-2-pentanone (29.42%, α-cedrol (26.98%, ∆3-carene (6.08%, and terpinen-4-ol (5.42%; the most OECs in the bark were di(2-ethylhexylphthalate (30.91%, cyclohexane (12.89%, caryophyllene oxide (8.90%, and α-pinene (4.59%. OECs of L. decidua wood were α-terpineol (26.06%, isoborneol (14.12%, camphene (11.78%, D-fenchyl alcohol (10.39%, and larixol (4.85%; OECs in the bark were larixol (33.29%, phthalic acid mono-2-ethylhexyl ester (16.96%, 13-epimanool (15.40%, and cyclohexane (8.44%.

Intra-Annual Xylem Growth of Larix principis-rupprechtii at Its Upper and Lower Distribution Limits on the Luyashan Mountain in North-Central China

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Yuan Jiang

2015-10-01

Full Text Available Altitude-related climatic factors, especially temperature, are important factors that affect tree growth in mountain forest ecosystems. The aims of this study were to estimate the intra-annual radial growth differences of Larix principis-rupprechtii (L. principis-rupprechtii between its upper and lower distribution limits, at 2740 and 2040 m a.s.l, respectively. Dynamics of xylem growth were observed by collecting microcore samples weekly during the 2011 growth season. The result indicated that different strategies were adopted at the two selected sites. Trees at the upper distribution limit adopted an “intensive strategy” with higher maximum growth rates (0.69 cell·day−1 within a shorter duration of 95 days, producing 21 new tracheids. By contrast, trees at the lower distribution limit exhibited an “extensive strategy” with lower maximum growth rates (0.53 cell·day−1 over a longer duration of 135 days, producing 50 tracheids. The soil temperature was probably the main factor limiting the onset of cambial activity for L. principis-rupprechtii, its daily mean thresholds for onset were 0 °C and 1.4 °C at the upper and lower distribution limits, respectively. These results indicate that L. principis-rupprechtii is able to adjust its xylem growth according to environmental conditions.

Extraction of Dihydroquercetin from Larix gmelinii with Ultrasound-Assisted and Microwave-Assisted Alternant Digestion

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Yuangang Zu

2012-07-01

Full Text Available An ultrasound and microwave assisted alternant extraction method (UMAE was applied for extracting dihydroquercetin (DHQ from Larix gmelinii wood. This investigation was conducted using 60% ethanol as solvent, 1:12 solid to liquid ratio, and 3 h soaking time. The optimum treatment time was ultrasound 40 min, microwave 20 min, respectively, and the extraction was performed once. Under the optimized conditions, satisfactory extraction yield of the target analyte was obtained. Relative to ultrasound-assisted or microwave-assisted method, the proposed approach provides higher extraction yield. The effect of DHQ of different concentrations and synthetic antioxidants on oxidative stability in soy bean oil stored for 20 days at different temperatures (25 °C and 60 °C was compared. DHQ was more effective in restraining soy bean oil oxidation, and a dose-response relationship was observed. The antioxidant activity of DHQ was a little stronger than that of BHA and BHT. Soy bean oil supplemented with 0.08 mg/g DHQ exhibited favorable antioxidant effects and is preferable for effectively avoiding oxidation. The L. gmelinii wood samples before and after extraction were characterized by scanning electron microscopy. The results showed that the UMAE method is a simple and efficient technique for sample preparation.

Mapping Spatial Distribution of Larch Plantations from Multi-Seasonal Landsat-8 OLI Imagery and Multi-Scale Textures Using Random Forests

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Tian Gao

2015-02-01

Full Text Available The knowledge about spatial distribution of plantation forests is critical for forest management, monitoring programs and functional assessment. This study demonstrates the potential of multi-seasonal (spring, summer, autumn and winter Landsat-8 Operational Land Imager imageries with random forests (RF modeling to map larch plantations (LP in a typical plantation forest landscape in North China. The spectral bands and two types of textures were applied for creating 675 input variables of RF. An accuracy of 92.7% for LP, with a Kappa coefficient of 0.834, was attained using the RF model. A RF-based importance assessment reveals that the spectral bands and bivariate textural features calculated by pseudo-cross variogram (PC strongly promoted forest class-separability, whereas the univariate textural features influenced weakly. A feature selection strategy eliminated 93% of variables, and then a subset of the 47 most essential variables was generated. In this subset, PC texture derived from summer and winter appeared the most frequently, suggesting that this variability in growing peak season and non-growing season can effectively enhance forest class-separability. A RF classifier applied to the subset led to 91.9% accuracy for LP, with a Kappa coefficient of 0.829. This study provides an insight into approaches for discriminating plantation forests with phenological behaviors.

Topography- and Species-Dependent Climatic Responses in Radial Growth of Picea meyeri and Larix principis-rupprechtii in the Luyashan Mountains of North-Central China

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Wentao Zhang

2015-01-01

Full Text Available Dendroecological techniques were used to examine the relationships between topographic aspects, climate factors and radial growth of Picea meyeri and Larix principis-rupprechtii in Luyashan Mountains, North-Central China. Four sites were selected at timberline and totally 67 trees and 134 cores were collected. Pearson correlation and regression surface analysis were conducted to reveal the growth-climate relationships. The results indicated that the two species both showed significant negative correlations with temperature during preceding November on the two topographic aspects. On both slope aspects, growth of P. meyeri exhibited significant negative correlations with precipitation in current June, whereas growth of L. principis-rupprechtii showed significant negative correlations with precipitation in preceding September. On north-facing slope, tree growth was limited by low temperature in early growing season, which not shown on south-facing slope. If climate warming continues, L. principis-rupprechtii may be more favored and a reverse between relationships with temperature and precipitation maybe occur in growth of trees. Treeline position on the north-facing slope may possess a greater potential for elevation shifting than the south-facing slope. Our results supply useful information for discussing the potential effect of future climate on the forest growth in North-Central China.

Hybrid mimics and hybrid vigor in Arabidopsis

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Wang, Li; Greaves, Ian K.; Groszmann, Michael; Wu, Li Min; Dennis, Elizabeth S.; Peacock, W. James

2015-01-01

F1 hybrids can outperform their parents in yield and vegetative biomass, features of hybrid vigor that form the basis of the hybrid seed industry. The yield advantage of the F1 is lost in the F2 and subsequent generations. In Arabidopsis, from F2 plants that have a F1-like phenotype, we have by recurrent selection produced pure breeding F5/F6 lines, hybrid mimics, in which the characteristics of the F1 hybrid are stabilized. These hybrid mimic lines, like the F1 hybrid, have larger leaves than the parent plant, and the leaves have increased photosynthetic cell numbers, and in some lines, increased size of cells, suggesting an increased supply of photosynthate. A comparison of the differentially expressed genes in the F1 hybrid with those of eight hybrid mimic lines identified metabolic pathways altered in both; these pathways include down-regulation of defense response pathways and altered abiotic response pathways. F6 hybrid mimic lines are mostly homozygous at each locus in the genome and yet retain the large F1-like phenotype. Many alleles in the F6 plants, when they are homozygous, have expression levels different to the level in the parent. We consider this altered expression to be a consequence of transregulation of genes from one parent by genes from the other parent. Transregulation could also arise from epigenetic modifications in the F1. The pure breeding hybrid mimics have been valuable in probing the mechanisms of hybrid vigor and may also prove to be useful hybrid vigor equivalents in agriculture. PMID:26283378

Effects of fire disturbance on soil respiration in the non-growing season in a Larix gmelinii forest in the Daxing'an Mountains, China.

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Hu, Tongxin; Sun, Long; Hu, Haiqing; Guo, Futao

2017-01-01

In boreal forests, fire is an important part of the ecosystem that greatly influences soil respiration, which in turn affects the carbon balance. Wildfire can have a significant effect on soil respiration and it depends on the fire severity and environmental factors (soil temperature and snow water equivalent) after fire disturbance. In this study, we quantified post-fire soil respiration during the non-growing season (from November to April) in a Larix gmelinii forest in Daxing'an Mountains of China. Soil respiration was measured in the snow-covered and snow-free conditions with varying degrees of natural burn severity forests. We found that soil respiration decreases as burn severity increases. The estimated annual C efflux also decreased with increased burn severity. Soil respiration during the non-growing season approximately accounted for 4%-5% of the annual C efflux in all site types. Soil temperature (at 5 cm depth) was the predominant determinant of non-growing season soil respiration change in this area. Soil temperature and snow water equivalent could explain 73%-79% of the soil respiration variability in winter snow-covering period (November to March). Mean spring freeze-thaw cycle (FTC) period (April) soil respiration contributed 63% of the non-growing season C efflux. Our finding is key for understanding and predicting the potential change in the response of boreal forest ecosystems to fire disturbance under future climate change.

Methylated Fatty Acids from Heartwood and Bark of Pinus sylvestris, Abies alba, Picea abies, and Larix decidua: Effect of Strong Acid Treatment

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Mohamed Zidan Mohamed Salem

2015-09-01

Full Text Available Methylated fatty acid (FA compounds in the heartwood and bark of some softwood species, specifically Pinus sylvestris, Abies alba, Picea abies, and Larix decidua, grown in the Czech Republic were evaluated. Strong H2SO4 was used for methylation of the lipids. The highest content of lipid was found in P. abies bark (40.132 mg/g o.d. sample, and the lowest content was in A. alba wood (11.027 mg/g o.d. sample. The highest concentration of FAs was observed in L. decidua bark. The highest percentages of FAs in wood of P. sylvestris were arachidic acid and oleic acid. In bark, the highest percentages of FAs were stearic acid, palmitic acid, and oleic acid. The FAs with the highest concentrations in A. alba wood were arachidic acid, palmitic acid, pentadecanoic acid, and margarinic, and those in bark were behenic acid, lignoceric acid, and arachidic acid. P. abies wood FAs showed arachidic acid, palmitic acid, and margarinic acid, and the bark contained lignoceric acid and arachidic acid. The FAs of L. decidua wood were arachidic acid, palmitic acid, and stearic acid, and in bark they were pentacosylic acid, docosahexaenoic acid (DHA, lignoceric acid, arachidic acid, and behenic acid. The lack of typically dominant unsaturated fatty acids (e.g. 18:1, 18:2, compared to literature values were attributed to the application of strong acid for the hydrolysis.

Application of micro-PIXE, MRI and light microscopy for research in wood science and dendroecology

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Merela, M.; Pelicon, P.; Vavpetic, P.; Regvar, M.; Vogel-Mikus, K.; Sersa, I.; Policnik, H.; Pokorny, B.; Levanic, T.; Oven, P.

2009-01-01

Beech (Fagus sylvatica L.) branches were topped and after five months the wound response was analyzed by PIXE, 3D-MRI and light microscopy. From freshly cut and deeply frozen sample 30 μm thick longitudinal-radial tissue sections were prepared for anatomical investigations and micro-PIXE analysis. Light microscopy revealed the structural response to wounding, i.e. occurrence of the reaction zone between the exposed and dehydrated dead tissue and healthy sound wood. The reaction zone was characterized by tylosis in vessels and accumulation of colored deposits in parenchyma cells, fibres and vessels. 3D MRI of a parallel sample showed that the moisture content in the reaction zone was three times higher than in normal healthy wood. Micro-PIXE mapping at margins of compromised wood in beech revealed an increased concentration of potassium in the reaction zone. The increase in the calcium concentration was associated with the dehydrated tissue adjacent to reaction zones. In addition, micro-PIXE was used to determine the elemental distribution in annual tree rings. This may be relevant for retrospective assessment of environmental pollution in wood by measuring yearly increments as a biomonitoring tool. The analysis of European larch (Larix decidua Mill.) wood revealed a high similarity between optical characteristics (i.e. late versus earlywood) and elemental (e.g. Cl, K, Ca, Mn, Zn) distribution.

Hybrid Propulsion Demonstration Program 250K Hybrid Motor

Science.gov (United States)

Story, George; Zoladz, Tom; Arves, Joe; Kearney, Darren; Abel, Terry; Park, O.

2003-01-01

The Hybrid Propulsion Demonstration Program (HPDP) program was formed to mature hybrid propulsion technology to a readiness level sufficient to enable commercialization for various space launch applications. The goal of the HPDP was to develop and test a 250,000 pound vacuum thrust hybrid booster in order to demonstrate hybrid propulsion technology and enable manufacturing of large hybrid boosters for current and future space launch vehicles. The HPDP has successfully conducted four tests of the 250,000 pound thrust hybrid rocket motor at NASA's Stennis Space Center. This paper documents the test series.

Pulp quality from small-diameter trees.

Science.gov (United States)

G.C. Myers; S. Kumar; R.R. Gustafson; R.J. Barbour; S.M. Abubakr

1997-01-01

Kraft and thermomechanical (TMP) pulps were prepared and evaluated from lodgepole pine and mixed Douglas-fir/western larch sawmill residue chips; lodgepole pine, Douglas-fir, and western larch submerchantable logs; and lodgepole pine, Douglas-fir, and western larch small trees and tops. Kraft pulp from small trees and tops was identical to that from submerchantable...

Effects of fire disturbance on soil respiration in the non-growing season in a Larix gmelinii forest in the Daxing'an Mountains, China.

Directory of Open Access Journals (Sweden)

Tongxin Hu

Full Text Available In boreal forests, fire is an important part of the ecosystem that greatly influences soil respiration, which in turn affects the carbon balance. Wildfire can have a significant effect on soil respiration and it depends on the fire severity and environmental factors (soil temperature and snow water equivalent after fire disturbance. In this study, we quantified post-fire soil respiration during the non-growing season (from November to April in a Larix gmelinii forest in Daxing'an Mountains of China. Soil respiration was measured in the snow-covered and snow-free conditions with varying degrees of natural burn severity forests. We found that soil respiration decreases as burn severity increases. The estimated annual C efflux also decreased with increased burn severity. Soil respiration during the non-growing season approximately accounted for 4%-5% of the annual C efflux in all site types. Soil temperature (at 5 cm depth was the predominant determinant of non-growing season soil respiration change in this area. Soil temperature and snow water equivalent could explain 73%-79% of the soil respiration variability in winter snow-covering period (November to March. Mean spring freeze-thaw cycle (FTC period (April soil respiration contributed 63% of the non-growing season C efflux. Our finding is key for understanding and predicting the potential change in the response of boreal forest ecosystems to fire disturbance under future climate change.

Hybrid2 - The hybrid power system simulation model

Energy Technology Data Exchange (ETDEWEB)

Baring-Gould, E.I.; Green, H.J.; Dijk, V.A.P. van [National Renewable Energy Lab., Golden, CO (United States); Manwell, J.F. [Univ. of Massachusetts, Amherst, MA (United States)

1996-12-31

There is a large-scale need and desire for energy in remote communities, especially in the developing world; however the lack of a user friendly, flexible performance prediction model for hybrid power systems incorporating renewables hindered the analysis of hybrids as options to conventional solutions. A user friendly model was needed with the versatility to simulate the many system locations, widely varying hardware configurations, and differing control options for potential hybrid power systems. To meet these ends, researchers from the National Renewable Energy Laboratory (NREL) and the University of Massachusetts (UMass) developed the Hybrid2 software. This paper provides an overview of the capabilities, features, and functionality of the Hybrid2 code, discusses its validation and future plans. Model availability and technical support provided to Hybrid2 users are also discussed. 12 refs., 3 figs., 4 tabs.

Marine Fish Hybridization

KAUST Repository

He, Song

2017-04-01

Natural hybridization is reproduction (without artificial influence) between two or more species/populations which are distinguishable from each other by heritable characters. Natural hybridizations among marine fishes were highly underappreciated due to limited research effort; it seems that this phenomenon occurs more often than is commonly recognized. As hybridization plays an important role in biodiversity processes in the marine environment, detecting hybridization events and investigating hybridization is important to understand and protect biodiversity. The first chapter sets the framework for this disseration study. The Cohesion Species Concept was selected as the working definition of a species for this study as it can handle marine fish hybridization events. The concept does not require restrictive species boundaries. A general history and background of natural hybridization in marine fishes is reviewed during in chapter as well. Four marine fish hybridization cases were examed and documented in Chapters 2 to 5. In each case study, at least one diagnostic nuclear marker, screened from among ~14 candidate markers, was found to discriminate the putative hybridizing parent species. To further investigate genetic evidence to support the hybrid status for each hybrid offspring in each case, haploweb analysis on diagnostic markers (nuclear and/or mitochondrial) and the DAPC/PCA analysis on microsatellite data were used. By combining the genetic evidences, morphological traits, and ecological observations together, the potential reasons that triggered each hybridization events and the potential genetic/ecology effects could be discussed. In the last chapter, sequences from 82 pairs of hybridizing parents species (for which COI barcoding sequences were available either on GenBank or in our lab) were collected. By comparing the COI fragment p-distance between each hybridizing parent species, some general questions about marine fish hybridization were discussed: Is

Effect of temperate climate tree species on gross ammonification, gross nitrification and N2O formation

Science.gov (United States)

Brüggemann, N.; Rosenkranz, P.; Papen, H.; Butterbach-Bahl, K.

2003-04-01

Microbial nitrogen turnover processes in the soil, like ammonification, nitrification and denitrification, play an important role in the formation of nitrous oxide (N2O): (i) ammonification, because it releases nitrogen from organic material in the form of ammonium (NH4+), which in turn can serve as substrate for nitrification; (ii) nitrification itself (i.e. the turnover of NH4+ to nitrate, NO3-), during which nitric oxide (NO) and N2O can be released as by-products at varying ratios; (iii) denitrification, in which NO3- serves as electron acceptor and is converted to molecular nitrogen (N2) via NO and N2O as intermediates, that can also be partially lost to the atmosphere. Temperate forest soils are a substantial source of atmospheric N2O contributing up to 10% to the total atmospheric N2O budget. However, this figure is afflicted with a huge uncertainty due to a number of factors governing the soil N2O formation, consumption, release and uptake, which are not fully understood at present. To one of these factors belongs the influence of the tree species on nitrogen turnover processes in the soil and the formation of N trace gases related with them. The aim of the present work was to analyse this tree species effect for the temperate climate region. For this purpose the effect of five different temperate tree species, having the same age and growing on the same soil in direct vicinity to each other, on gross ammonification and gross nitrification as well as on N2O formation was investigated. The trees (common beech, Fagus sylvatica; pedunculate oak, Quercus robur; Norway spruce, Picea abies; Japanese larch, Larix leptolepis; mountain pine, Pinus mugo) were part of a species trial in Western Jutland, Denmark, established in 1965 on a former sandy heathland. Samples from the soil under these five tree species were taken in spring and in summer 2002, respectively, differentiating between organic layer and mineral soil. The gross rates of ammonification as well of

Intuitionistic hybrid logic

DEFF Research Database (Denmark)

Braüner, Torben

2011-01-01

Intuitionistic hybrid logic is hybrid modal logic over an intuitionistic logic basis instead of a classical logical basis. In this short paper we introduce intuitionistic hybrid logic and we give a survey of work in the area.......Intuitionistic hybrid logic is hybrid modal logic over an intuitionistic logic basis instead of a classical logical basis. In this short paper we introduce intuitionistic hybrid logic and we give a survey of work in the area....

Energy Efficiency Comparison between Hydraulic Hybrid and Hybrid Electric Vehicles

Directory of Open Access Journals (Sweden)

Jia-Shiun Chen

2015-05-01

Full Text Available Conventional vehicles tend to consume considerable amounts of fuel, which generates exhaust gases and environmental pollution during intermittent driving cycles. Therefore, prospective vehicle designs favor improved exhaust emissions and energy consumption without compromising vehicle performance. Although pure electric vehicles feature high performance and low pollution characteristics, their limitations are their short driving range and high battery costs. Hybrid electric vehicles (HEVs are comparatively environmentally friendly and energy efficient, but cost substantially more compared with conventional vehicles. Hydraulic hybrid vehicles (HHVs are mainly operated using engines, or using alternate combinations of engine and hydraulic power sources while vehicles accelerate. When the hydraulic system accumulator is depleted, the conventional engine reengages; concurrently, brake-regenerated power is recycled and reused by employing hydraulic motor–pump modules in circulation patterns to conserve fuel and recycle brake energy. This study adopted MATLAB Simulink to construct complete HHV and HEV models for backward simulations. New European Driving Cycles were used to determine the changes in fuel economy. The output of power components and the state-of-charge of energy could be retrieved. Varying power component models, energy storage component models, and series or parallel configurations were combined into seven different vehicle configurations: the conventional manual transmission vehicle, series hybrid electric vehicle, series hydraulic hybrid vehicle, parallel hybrid electric vehicle, parallel hydraulic hybrid vehicle, purely electric vehicle, and hydraulic-electric hybrid vehicle. The simulation results show that fuel consumption was 21.80% lower in the series hydraulic hybrid vehicle compared to the series hybrid electric vehicle; additionally, fuel consumption was 3.80% lower in the parallel hybrid electric vehicle compared to the

Hybride textuelle Strukturen und hybride textuelle Einheiten. Ein ...

African Journals Online (AJOL)

carrying set of all hybrid hierarchical structures are element-heterogeneous whilst the structure- carrying set of all ... grams of hierarchical hybrid article structures, the nodes for those text segments that establish the hybrid status of .... der; d ∈ ArtA ⊣ G|WAr (= Artikelangabe, anhand derer das Genus (= G) und zugleich die ...

Histoire tertiaire de l'Arche de Brahmaputra ; son rôle dans la prospection des hydrocarbures du Haut Assam (Inde (résumé Tertiary History of Brahmaputra Arch. Its Role in Hydrocarbon Prospects of Upper Assam, India (Abstract

Directory of Open Access Journals (Sweden)

Murty K. N.

2006-10-01

Full Text Available On analyse l'histoire tertiaire de la plate-forme du Haut Assam (Inde et on discute les facteurs géologiques responsables du caractère pétrolier de cette importante province ainsi que ses relations avec la ceinture mobile de Naga au Sud-Est et avec l'avant-fosse himalayenne au Nord-Ouest. A cette intention, on a préparé des cartes paléologiques pour différentes formations dans la vallée supérieure de l'Assam, basées sur de nombreux puits et levers géophysiques. A partir de ces cartes, on a construit une série de coupes paléogéologiques pour illustrer l'évolution structurale de la plate-forme du haut Assam. Cette étude montre que la structure régionale de la haute vallée de l'Assam est en subsurface une arche large - l'Arche de Brahrnaputra - parallèle à, et juste au sud de la rivière Brahmaputra, formée par un double basculernent opposé : un ancien talus vers le Sud-Est durant le Paléogène et l'autre tourné vers le Nord-Ouest pendant le Mio-Pliocène. On peut identifier deux phases de migration des hydrocarbures. L'étude permet l'affirmation d'objectifs futurs en Haut Assam. Cette arche a une histoire géologique voisine de celle de l'arche de Bend du centre-nord du Texas et de l'arche de Hunton-Seminole-Ozark en Oklahoma où de riches gisements ont été trouvés dans presque tous les terrains impliqués dans le bombement. The Tertiary history of Upper Assam shelf, India is analysed. The geological factors responsible for making this an important petroleum province and ifs relationship with the Nago mobile belt in the south-east and the Himalayan fore deep in the north-vvest ore discussed. Sub-crop maps of différent geological formations in Upper Assam Valley based on a number of drilled wells and various geophysical surveys ore prepared for this purpose. From these maps, a series of palaeogeological sections are constructed to illustrate the structural evolution of the Upper Assam shelf. The study reveals thot the

Hybrid platform. Economical hybrid drive for commercial vehicles; Hybrid Plattform. Wirtschaftlicher Hybridantrieb fuer Nutzfahrzeuge

Energy Technology Data Exchange (ETDEWEB)

Wallner, S.; Lamke, M.; Mohr, M.; Sedlacek, M.; Speck, F.D. [ZF Friedrichshafen AG, Friedrichshafen (Germany)

2011-07-01

Up to now, hybrid systems have been adapted to their specific requirements in the various applications for trucks, buses as well as mobile and building machines. From a technical point of view, this does indeed result in optimized hybrid drives for each single vehicle application, but due to small volumes, such single developments are critical from a business point of view. ZF Friedrichshafen AG is providing a solution to the technical and economical requirements of the cost-sensitive CV segment in the form of a modular CV parallel hybrid platform composed of a hybrid module system, an inverter, a battery system, and a hybrid software integrated into the overall vehicle. Thanks to the intelligent combination of assemblies and the use of as many identical parts as possible, platforms are realized which cover power ranges between 60 and 120 kW, voltage ranges between 350 and 650 V, and battery capacities between 2 and 4 kWh. The dimensions of the platform elements are such that integration into the diverse commercial vehicle applications is made easy. The hybrid software required for the vehicle-specific functions is also configurable for the mentioned CV applications. (orig.)

Fusion-fission hybrid reactors

International Nuclear Information System (INIS)

Greenspan, E.

1984-01-01

This chapter discusses the range of characteristics attainable from hybrid reactor blankets; blanket design considerations; hybrid reactor designs; alternative fuel hybrid reactors; multi-purpose hybrid reactors; and hybrid reactors and the energy economy. Hybrid reactors are driven by a fusion neutron source and include fertile and/or fissile material. The fusion component provides a copious source of fusion neutrons which interact with a subcritical fission component located adjacent to the plasma or pellet chamber. Fissile fuel and/or energy are the main products of hybrid reactors. Topics include high F/M blankets, the fissile (and tritium) breeding ratio, effects of composition on blanket properties, geometrical considerations, power density and first wall loading, variations of blanket properties with irradiation, thermal-hydraulic and mechanical design considerations, safety considerations, tokamak hybrid reactors, tandem-mirror hybrid reactors, inertial confinement hybrid reactors, fusion neutron sources, fissile-fuel and energy production ability, simultaneous production of combustible and fissile fuels, fusion reactors for waste transmutation and fissile breeding, nuclear pumped laser hybrid reactors, Hybrid Fuel Factories (HFFs), and scenarios for hybrid contribution. The appendix offers hybrid reactor fundamentals. Numerous references are provided

The effects of climate, permafrost and fire on vegetation change in Siberia in a changing climate

Energy Technology Data Exchange (ETDEWEB)

Tchebakova, N M; Parfenova, E [V N Sukachev Institute of Forest, Siberian Branch of the Russian Academy of Sciences, Academgorodok, Krasnoyarsk, 660036 (Russian Federation); Soja, A J, E-mail: ncheby@forest.akadem.r, E-mail: Amber.J.Soja@nasa.go [National Institute of Aerospace (NIA), NASA Langley Research Center, Climate Sciences, 21 Langley Boulevard, Mail Stop 420, Hampton, VA 23681-2199 (United States)

2009-10-15

Observations and general circulation model projections suggest significant temperature increases in Siberia this century that are expected to have profound effects on Siberian vegetation. Potential vegetation change across Siberia was modeled, coupling our Siberian BioClimatic Model with several Hadley Centre climate change scenarios for 2020, 2050 and 2080, with explicit consideration of permafrost and fire activity. In the warmer and drier climate projected by these scenarios, Siberian forests are predicted to decrease and shift northwards and forest-steppe and steppe ecosystems are predicted to dominate over half of Siberia due to the dryer climate by 2080. Despite the large predicted increases in warming, permafrost is not predicted to thaw deep enough to sustain dark (Pinus sibirica, Abies sibirica, and Picea obovata) taiga. Over eastern Siberia, larch (Larix dahurica) taiga is predicted to continue to be the dominant zonobiome because of its ability to withstand continuous permafrost. The model also predicts new temperate broadleaf forest and forest-steppe habitats by 2080. Potential fire danger evaluated with the annual number of high fire danger days (Nesterov index is 4000-10 000) is predicted to increase by 2080, especially in southern Siberia and central Yakutia. In a warming climate, fuel load accumulated due to replacement of forest by steppe together with frequent fire weather promotes high risks of large fires in southern Siberia and central Yakutia, where wild fires would create habitats for grasslands because the drier climate would no longer be suitable for forests.

Plant response to climate change along the forest-tundra ecotone in northeastern Siberia.

Science.gov (United States)

Berner, Logan T; Beck, Pieter S A; Bunn, Andrew G; Goetz, Scott J

2013-11-01

Russia's boreal (taiga) biome will likely contract sharply and shift northward in response to 21st century climatic change, yet few studies have examined plant response to climatic variability along the northern margin. We quantified climate dynamics, trends in plant growth, and growth-climate relationships across the tundra shrublands and Cajander larch (Larix cajanderi Mayr.) woodlands of the Kolyma river basin (657 000 km(2) ) in northeastern Siberia using satellite-derived normalized difference vegetation indices (NDVI), tree ring-width measurements, and climate data. Mean summer temperatures (Ts ) increased 1.0 °C from 1938 to 2009, though there was no trend (P > 0.05) in growing year precipitation or climate moisture index (CMIgy ). Mean summer NDVI (NDVIs ) increased significantly from 1982 to 2010 across 20% of the watershed, primarily in cold, shrub-dominated areas. NDVIs positively correlated (P  0.05), which significantly correlated with NDVIs (r = 0.44, P < 0.05, 1982-2007). Both satellite and tree-ring analyses indicated that plant growth was constrained by both low temperatures and limited moisture availability and, furthermore, that warming enhanced growth. Impacts of future climatic change on forests near treeline in Arctic Russia will likely be influenced by shifts in both temperature and moisture, which implies that projections of future forest distribution and productivity in this area should take into account the interactions of energy and moisture limitations. © 2013 John Wiley & Sons Ltd.

Explaining the dependence of climatic response of tree radial growth on permafrost

Science.gov (United States)

Bryukhanova, Marina; Benkova, Anna; von Arx, Georg; Fonti, Patrick; Simanko, Valentina; Kirdyanov, Alexander; Shashkin, Alexander

2015-04-01

In northern regions of Siberia it is infrequent to have long-term observations of the variability of soil features, phenological data, duration of the growing season, which can be used to infer the influence of the environment on tree growth and productivity. The best way to understand tree-growth and tree responses to environmental changes is to make use of mechanistic models, allowing to combine already available experiment/field data with other parameters based on biological principles of tree growth. The goal of our study is to estimate which tree species (deciduous, conifer deciduous or conifer evergreen) is more plastic under possible climate changes in permafrost zone. The studied object is located in the northern part of central Siberia, Russia (64°N, 100°E). The study plot was selected within a post-fire succession and representatives for 100 years old even aged mixed forest of Larix gmelinii (Rupr.) Rupr. and Betula pubescens Ehrh. with few exemplars of Spruce (Picea obovata Ledeb.). To understand physiological response of larch, birch and spruce trees to climatic changes the ecological-physiological process-based model of tree photosynthesis (Benkova and Shashkin 2003) was applied. Multiparametric tree-ring chronologies were analyzed and correlated with climatic parameters over the last 77 years. This work is supported by the Ministry of Education and Science of the Russian Federation (Grant from the President of RF for Young Scientists MK-1589.2014.4).

Hybrid reactors

International Nuclear Information System (INIS)

Moir, R.W.

1980-01-01

The rationale for hybrid fusion-fission reactors is the production of fissile fuel for fission reactors. A new class of reactor, the fission-suppressed hybrid promises unusually good safety features as well as the ability to support 25 light-water reactors of the same nuclear power rating, or even more high-conversion-ratio reactors such as the heavy-water type. One 4000-MW nuclear hybrid can produce 7200 kg of 233 U per year. To obtain good economics, injector efficiency times plasma gain (eta/sub i/Q) should be greater than 2, the wall load should be greater than 1 MW.m -2 , and the hybrid should cost less than 6 times the cost of a light-water reactor. Introduction rates for the fission-suppressed hybrid are usually rapid

Corporate Hybrid Bonds

OpenAIRE

Ahlberg, Johan; Jansson, Anton

2016-01-01

Hybrid securities do not constitute a new phenomenon in the Swedish capital markets. Most commonly, hybrids issued by Swedish real estate companies in recent years are preference shares. Corporate hybrid bonds on the other hand may be considered as somewhat of a new-born child in the family of hybrid instruments. These do, as all other hybrid securities, share some equity-like and some debt-like characteristics. Nevertheless, since 2013 the interest for the instrument has grown rapidly and ha...

Cardiac hybrid imaging

Energy Technology Data Exchange (ETDEWEB)

Gaemperli, Oliver [University Hospital Zurich, Cardiac Imaging, Zurich (Switzerland); University Hospital Zurich, Nuclear Cardiology, Cardiovascular Center, Zurich (Switzerland); Kaufmann, Philipp A. [University Hospital Zurich, Cardiac Imaging, Zurich (Switzerland); Alkadhi, Hatem [University Hospital Zurich, Institute of Diagnostic and Interventional Radiology, Zurich (Switzerland)

2014-05-15

Hybrid cardiac single photon emission computed tomography (SPECT)/CT imaging allows combined assessment of anatomical and functional aspects of cardiac disease. In coronary artery disease (CAD), hybrid SPECT/CT imaging allows detection of coronary artery stenosis and myocardial perfusion abnormalities. The clinical value of hybrid imaging has been documented in several subsets of patients. In selected groups of patients, hybrid imaging improves the diagnostic accuracy to detect CAD compared to the single imaging techniques. Additionally, this approach facilitates functional interrogation of coronary stenoses and guidance with regard to revascularization procedures. Moreover, the anatomical information obtained from CT coronary angiography or coronary artery calcium scores (CACS) adds prognostic information over perfusion data from SPECT. The use of cardiac hybrid imaging has been favoured by the dissemination of dedicated hybrid systems and the release of dedicated image fusion software, which allow simple patient throughput for hybrid SPECT/CT studies. Further technological improvements such as more efficient detector technology to allow for low-radiation protocols, ultra-fast image acquisition and improved low-noise image reconstruction algorithms will be instrumental to further promote hybrid SPECT/CT in research and clinical practice. (orig.)

Missing cycles: Effect of climate change on population dynamics

Indian Academy of Sciences (India)

population dynamics of the larch budmoth – an insect pest which causes massive defoliation of entire larch forests ... hypothesized that global warming has led to the collapse of the cycles ... When temperatures increase after winter, and the.

The plus-hybrid effect on the grain yield of two ZP maize hybrids

Directory of Open Access Journals (Sweden)

Božinović Sofija

2010-01-01

Full Text Available The combined effect of cytoplasmic male sterility and xenia on maize hybrid traits is referred to as the plus-hybrid effect. Two studied ZP hybrids differently responded to this effect for grain yield. All plus-hybrid combinations of the firstly observed hybrid had a higher yield than their fertile counterparts, but not significantly, while only one combination of the second hybrid positively responded, also without statistical significance. It seems that the observed effect mostly depended on the genotype of the female component.

Toronto hybrid taxi pilot

International Nuclear Information System (INIS)

Stevens, M.; Marans, B.

2009-10-01

This paper provided details of a hybrid taxi pilot program conducted to compare the on-road performance of Toyota Camry hybrid vehicles against conventional vehicles over a 1-year period in order to determine the business case and air emission reductions associated with the use of hybrid taxi cabs. Over 750,000 km worth of fuel consumption was captured from 10 Toyota Camry hybrids, a Toyota Prius, and 5 non-hybrid Camry vehicles over an 18-month period. The average real world fuel consumption for the taxis demonstrated that the Toyota Prius has the lowest cost of ownership, while the non-hybrid Camry has the highest cost of ownership. Carbon dioxide (CO 2 ) reductions associated with the 10 Camry hybrid taxis were calculated at 236 tonnes over a 7-year taxi service life. Results suggested that the conversion of Toronto's 5680 taxis would yield annual CO 2 emission reductions of over 19,000 tonnes. All hybrid purchasers identified themselves as highly likely to purchase a hybrid again. 5 tabs., 9 figs.

Toronto hybrid taxi pilot

Energy Technology Data Exchange (ETDEWEB)

Stevens, M. [CrossChasm Technologies, Cambridge, ON (Canada); Marans, B. [Toronto Atmospheric Fund, ON (Canada)

2009-10-15

This paper provided details of a hybrid taxi pilot program conducted to compare the on-road performance of Toyota Camry hybrid vehicles against conventional vehicles over a 1-year period in order to determine the business case and air emission reductions associated with the use of hybrid taxi cabs. Over 750,000 km worth of fuel consumption was captured from 10 Toyota Camry hybrids, a Toyota Prius, and 5 non-hybrid Camry vehicles over an 18-month period. The average real world fuel consumption for the taxis demonstrated that the Toyota Prius has the lowest cost of ownership, while the non-hybrid Camry has the highest cost of ownership. Carbon dioxide (CO{sub 2}) reductions associated with the 10 Camry hybrid taxis were calculated at 236 tonnes over a 7-year taxi service life. Results suggested that the conversion of Toronto's 5680 taxis would yield annual CO{sub 2} emission reductions of over 19,000 tonnes. All hybrid purchasers identified themselves as highly likely to purchase a hybrid again. 5 tabs., 9 figs.

Continuity controlled Hybrid Automata

NARCIS (Netherlands)

Bergstra, J.A.; Middelburg, C.A.

We investigate the connections between the process algebra for hybrid systems of Bergstra and Middelburg and the formalism of hybrid automata of Henzinger et al. We give interpretations of hybrid automata in the process algebra for hybrid systems and compare them with the standard interpretation

Hybrid systems, optimal control and hybrid vehicles theory, methods and applications

CERN Document Server

Böhme, Thomas J

2017-01-01

This book assembles new methods showing the automotive engineer for the first time how hybrid vehicle configurations can be modeled as systems with discrete and continuous controls. These hybrid systems describe naturally and compactly the networks of embedded systems which use elements such as integrators, hysteresis, state-machines and logical rules to describe the evolution of continuous and discrete dynamics and arise inevitably when modeling hybrid electric vehicles. They can throw light on systems which may otherwise be too complex or recondite. Hybrid Systems, Optimal Control and Hybrid Vehicles shows the reader how to formulate and solve control problems which satisfy multiple objectives which may be arbitrary and complex with contradictory influences on fuel consumption, emissions and drivability. The text introduces industrial engineers, postgraduates and researchers to the theory of hybrid optimal control problems. A series of novel algorithmic developments provides tools for solving engineering pr...

Continuity Controlled Hybrid Automata

NARCIS (Netherlands)

Bergstra, J.A.; Middelburg, C.A.

2004-01-01

We investigate the connections between the process algebra for hybrid systems of Bergstra and Middelburg and the formalism of hybrid automata of Henzinger et al. We give interpretations of hybrid automata in the process algebra for hybrid systems and compare them with the standard interpretation of

Continuity controlled hybrid automata

NARCIS (Netherlands)

Bergstra, J.A.; Middelburg, C.A.

2004-01-01

We investigate the connections between the process algebra for hybrid systems of Bergstra and Middelburg and the formalism of hybrid automata of Henzinger et al. We give interpretations of hybrid automata in the process algebra for hybrid systems and compare them with the standard interpretation of

Continuity controlled hybrid automata

NARCIS (Netherlands)

Bergstra, J.A.; Middelburg, C.A.

2006-01-01

We investigate the connections between the process algebra for hybrid systems of Bergstra and Middelburg and the formalism of hybrid automata of Henzinger et al. We give interpretations of hybrid automata in the process algebra for hybrid systems and compare them with the standard interpretation of

A cool-temperate young larch plantation as a net methane source - A 4-year continuous hyperbolic relaxed eddy accumulation and chamber measurements

Science.gov (United States)

Ueyama, Masahito; Yoshikawa, Kota; Takagi, Kentaro

2018-07-01

Upland forests are thought to be methane (CH4) sinks due to oxidation by methanotrophs in aerobic soils. However, CH4 budget for upland forests are not well quantified at the ecosystem scale, when possible CH4 sources, such as small wet areas, exists in the ecosystem. Here, we quantified CH4 fluxes in a cool-temperate larch plantation based on four-year continuous measurements using the hyperbolic relaxed eddy accumulation (HREA) method and dynamic closed chambers with a laser-based analyzer. After filling data gaps for half-hourly data using machine-learning-based regressions, we found that the forest acted as a net CH4 source at the canopy scale: 30 ± 11 mg CH4 m-2 yr-1 in 2014, 56 ± 8 mg CH4 m-2 yr-1 in 2015, 154 ± 5 mg CH4 m-2 yr-1 in 2016, and 132 ± 6 mg CH4 m-2 yr-1 in 2017. Hotspot emissions from the edge of the pond could strongly contribute to the canopy-scale emissions. The magnitude of the hotspot emissions was 10-100 times greater than the order of the canopy-scale and chamber-based CH4 fluxes at the dry soils. The high temperatures with wet conditions stimulated the hotspot emissions, and thus induced canopy-scale CH4 emissions in the summer. Understanding and modeling the dynamics of hotspot emissions are important for quantifying CH4 budgets of upland forests. Micrometeorological measurements at various forests are required for revisiting CH4 budget of upland forests.

Hybrid functional pseudopotentials

Science.gov (United States)

Yang, Jing; Tan, Liang Z.; Rappe, Andrew M.

2018-02-01

The consistency between the exchange-correlation functional used in pseudopotential construction and in the actual density functional theory calculation is essential for the accurate prediction of fundamental properties of materials. However, routine hybrid density functional calculations at present still rely on generalized gradient approximation pseudopotentials due to the lack of hybrid functional pseudopotentials. Here, we present a scheme for generating hybrid functional pseudopotentials, and we analyze the importance of pseudopotential density functional consistency for hybrid functionals. For the PBE0 hybrid functional, we benchmark our pseudopotentials for structural parameters and fundamental electronic gaps of the Gaussian-2 (G2) molecular dataset and some simple solids. Our results show that using our PBE0 pseudopotentials in PBE0 calculations improves agreement with respect to all-electron calculations.

From hybrid swarms to swarms of hybrids

Science.gov (United States)

Stohlgren, Thomas J.; Szalanski, Allen L; Gaskin, John F.; Young, Nicholas E.; West, Amanda; Jarnevich, Catherine S.; Tripodi, Amber

2014-01-01

Science has shown that the introgression or hybridization of modern humans (Homo sapiens) with Neanderthals up to 40,000 YBP may have led to the swarm of modern humans on earth. However, there is little doubt that modern trade and transportation in support of the humans has continued to introduce additional species, genotypes, and hybrids to every country on the globe. We assessed the utility of species distributions modeling of genotypes to assess the risk of current and future invaders. We evaluated 93 locations of the genus Tamarix for which genetic data were available. Maxent models of habitat suitability showed that the hybrid, T. ramosissima x T. chinensis, was slightly greater than the parent taxa (AUCs > 0.83). General linear models of Africanized honey bees, a hybrid cross of Tanzanian Apis mellifera scutellata and a variety of European honey bee including A. m. ligustica, showed that the Africanized bees (AUC = 0.81) may be displacing European honey bees (AUC > 0.76) over large areas of the southwestern U.S. More important, Maxent modeling of sub-populations (A1 and A26 mitotypes based on mDNA) could be accurately modeled (AUC > 0.9), and they responded differently to environmental drivers. This suggests that rapid evolutionary change may be underway in the Africanized bees, allowing the bees to spread into new areas and extending their total range. Protecting native species and ecosystems may benefit from risk maps of harmful invasive species, hybrids, and genotypes.

Hybride textuelle Strukturen und hybride textuelle Einheiten. Ein Beitrag zur Theorie der Wörterbuchform

Directory of Open Access Journals (Sweden)

Herbert Ernst Wiegand

2011-10-01

Full Text Available

ZUSAMMENFASSUNG: In diesem Beitrag wird die Bildung, Darstellung und Leistung von hybriden textuellen Strukturen, die akzessive Einträge aufweisen, am Beispiel von Wörterbuchartikeln behandelt sowie erklärt, welche Eigenschaften hybride textuelle Einheiten haben. Ein Wörterbuchartikel eines Printwörterbuchs weist immer dann neben einer hierarchischen reinen eine hierarchische hybride Textkonstituentenstruktur auf, wenn in ihm mindestens ein funktionaler Angabezusatz auftritt, z.B. ein oben oder unten erweiternder oder ein binnenerweiternder. Da funktionale Angabezusätze Textsegmente mit Angabefunktion aber ohne Textkonstituentenstatus sind, werden sie durch nichtfunktionale Segmentation ermittelt, so dass neben funktionalen auch nichtfunktionale Textsegmente gegeben sind, die dann bei der Strukturbildung in die Trägermengen eingehen, so dass die Trägermengen aller hybriden hierarchischen Strukturen elementenheterogen, während die Trägermengen aller hierarchischen reinen Strukturen elementenhomogen sind. In den Strukturgraphen für hierarchische hybride Artikelstrukturen sind dann die Knoten für diejenigen Textsegmente, die den Hybridstatus der Strukturen bewirken, entweder durch Pfeilkanten für die textarchitektonischen oberhalb/unterhalb-Relationen mit den Knoten für die Textkonstituenten verbunden, so dass die Strukturgraphen architektonisch angereichert sind, oder durch besonders markierte Kanten, die die Knoten für die nichtfunktionalen Textsegmente und die für die binnenerweiternden funktionalen Angabezusätze mit den Knoten für die Textkonstituenten verbinden. Zu jedem Typ von hierarchischer reiner Artikelstruktur gehören mehrere Typen von hybriden Artikelstrukturen; entsprechendes gilt für hierarchische reine Angabestrukturen. Nur eine Auswahl aus den Typologien der hybriden Artikel- und Angabestrukturen wird behandelt sowie eine kleine Auswahl von hybriden textuellen Einheiten, die kriteriale Eigenschaften von zwei

Human hybrid hybridoma

Energy Technology Data Exchange (ETDEWEB)

Tiebout, R.F.; van Boxtel-Oosterhof, F.; Stricker, E.A.M.; Zeijlemaker, W.P.

1987-11-15

Hybrid hybridomas are obtained by fusion of two cells, each producing its own antibody. Several authors have reported the construction of murine hybrid hybridomas with the aim to obtain bispecific monoclonal antibodies. The authors have investigated, in a model system, the feasibility of constructing a human hybrid hybridoma. They fused two monoclonal cell lines: an ouabain-sensitive and azaserine/hypoxanthine-resistant Epstein-Barr virus-transformed human cell line that produces an IgG1kappa antibody directed against tetanus toxiod and an azaserine/hypoxanthine-sensitive and ouabain-resistant human-mouse xenohybrid cell line that produces a human IgG1lambda antibody directed against hepatitis-B surface antigen. Hybrid hybridoma cells were selected in culture medium containing azaserine/hypoxanthine and ouabain. The hybrid nature of the secreted antibodies was analyzed by means of two antigen-specific immunoassay. The results show that it is possible, with the combined use of transformation and xenohybridization techniques, to construct human hybrid hybridomas that produce bispecific antibodies. Bispecific antibodies activity was measured by means of two radioimmunoassays.

Henkin and Hybrid Logic

DEFF Research Database (Denmark)

Blackburn, Patrick Rowan; Huertas, Antonia; Manzano, Maria

2014-01-01

Leon Henkin was not a modal logician, but there is a branch of modal logic that has been deeply influenced by his work. That branch is hybrid logic, a family of logics that extend orthodox modal logic with special proposition symbols (called nominals) that name worlds. This paper explains why...... Henkin’s techniques are so important in hybrid logic. We do so by proving a completeness result for a hybrid type theory called HTT, probably the strongest hybrid logic that has yet been explored. Our completeness result builds on earlier work with a system called BHTT, or basic hybrid type theory...... is due to the first-order perspective, which lies at the heart of Henin’s best known work and hybrid logic....

Hybrid breeding in wheat: technologies to improve hybrid wheat seed production.

Science.gov (United States)

Whitford, Ryan; Fleury, Delphine; Reif, Jochen C; Garcia, Melissa; Okada, Takashi; Korzun, Viktor; Langridge, Peter

2013-12-01

Global food security demands the development and delivery of new technologies to increase and secure cereal production on finite arable land without increasing water and fertilizer use. There are several options for boosting wheat yields, but most offer only small yield increases. Wheat is an inbred plant, and hybrids hold the potential to deliver a major lift in yield and will open a wide range of new breeding opportunities. A series of technological advances are needed as a base for hybrid wheat programmes. These start with major changes in floral development and architecture to separate the sexes and force outcrossing. Male sterility provides the best method to block self-fertilization, and modifying the flower structure will enhance pollen access. The recent explosion in genomic resources and technologies provides new opportunities to overcome these limitations. This review outlines the problems with existing hybrid wheat breeding systems and explores molecular-based technologies that could improve the hybrid production system to reduce hybrid seed production costs, a prerequisite for a commercial hybrid wheat system.

Genetic basis to hybrid inviability is more complex than hybrid male sterility in Caenorhabditis nematodes.

Science.gov (United States)

Bundus, Joanna D; Wang, Donglin; Cutter, Asher D

2018-04-07

Hybrid male sterility often evolves before female sterility or inviability of hybrids, implying that the accumulation of divergence between separated lineages should lead hybrid male sterility to have a more polygenic basis. However, experimental evidence is mixed. Here, we use the nematodes Caenorhabditis remanei and C. latens to characterize the underlying genetic basis of asymmetric hybrid male sterility and hybrid inviability. We demonstrate that hybrid male sterility is consistent with a simple genetic basis, involving a single X-autosome incompatibility. We also show that hybrid inviability involves more genomic compartments, involving diverse nuclear-nuclear incompatibilities, a mito-nuclear incompatibility, and maternal effects. These findings demonstrate that male sensitivity to genetic perturbation may be genetically simple compared to hybrid inviability in Caenorhabditis and motivates tests of generality for the genetic architecture of hybrid incompatibility across the breadth of phylogeny.

Fusion-fission hybrids: environmental aspects and their role in hybrid rationale

International Nuclear Information System (INIS)

Holdren, J.P.

1981-01-01

The rationale for developing hybrids depends on real or perceived liabilities of relying on pure fission to do the same job. Quite possibly the main constraint on expanded use of fission will be neither lack of fuel nor high costs, but perceived environmental liabilities - radioactive wastes, reactor safety, and links to nuclear weaponry. The environmental characteristics of hybrid systems and pure-fisson systems are compared here in detail. The findings are that significant environmental advantages for hybrids cannot now be demonstrated and may not exist. Therefore, if environmental drawbacks constrain the application of pure fission, hybrids probably also will be thus constrained

S 400 BlueHYBRID. First hybrid vehicle with Li-ion technology; S 400 BlueHYBRID. Erstes Hybridfahrzeug mit Li-Ionen-Technologie

Energy Technology Data Exchange (ETDEWEB)

Vollrath, Oliver; Armstrong, Neil; Schenk, Juergen; Bitsche, Otmar; Lamm, Arnold [Daimler AG, Stuttgart (Germany)

2009-07-01

Mercedes Benz advances the electrification of the drive strand in all performance classes and in all models from the start-stop system till to the full hybrid. Thereby, the S 400 BlueHYBRID presents the first Mercedes-Benz hybrid. Equipped with the characteristics of a start-stop system, with a recovery of the brake energy and with an electrical support of the drive, this hybrid obtains a saving of the consumption of approximately 20 %. By means of the design of the components and by means of the selection of a standard installation size, all hybrid-specific construction units in the vehicle porch could be arranged. Here, a special role comes to the used battery technology, since it became possible to arrange the hybrid battery in the size and the building area of a conventional starter battery accordingly.

Changes in tracheid and ray traits in fire scars of North American conifers and their ecophysiological implications

Science.gov (United States)

Arbellay, Estelle; Stoffel, Markus; Sutherland, Elaine K.; Smith, Kevin T.; Falk, Donald A.

2014-01-01

Background and Aims Fire scars have been widely used as proxies for the reconstruction of fire history; however, little is known about the impact of fire injury on wood anatomy. This study investigates changes in tracheid and ray traits in fire scars of Douglas fir (Pseudotsuga menziesii), western larch (Larix occidentalis) and ponderosa pine (Pinus ponderosa), and discusses their ecophysiological implications for tree recovery from fire. Methods Transverse and tangential microsections were prepared for light microscopy and image analysis. Measurements of tracheids and rays were made in the three spatial dimensions: axially (at different section heights), radially (in different rings) and tangentially (with increasing distance from the wound margin). Key Results Changes were strongest in the first year after fire injury, with a decrease in tracheid size (by 25–30 %) and an increase in tracheid density (by 21–53 %) for the three species. In addition, an increase in ray size (by 5–27 %) and an increase in ray density (by 19–36 %) were found in P. menziesii and L. occidentalis. Changes were comparable along the fire-injured stem and were often most marked close to the fire scar. Conclusions The differentiation after fire injury of narrower and more numerous tracheids expresses a trade-off between hydraulic safety and hydraulic efficiency, while that of larger and more numerous rays serves compartmentalization and wound closure, mechanical strength and defence responses. Pinus ponderosa does not generally produce more ray tissue after fire injury and thus appears to be more adapted to fire. PMID:24941999

Thermal analysis of wood of the main tree species of Central Siberia

Directory of Open Access Journals (Sweden)

S. R. Loskutov

2015-12-01

Full Text Available Thermal decomposition of wood from coniferous and deciduous species of Siberia has been studied using thermogravimetry (TG and differential scanning calorimetry (DSC. The tree species were larch Larix sibirica Ledeb., Scots pine Pinus sylvestris L., spruce Picea obovata Ledeb., fir Abies sibirica Ledeb., Siberian pine Pinus sibirica Du Tour., birch Betula pendula Roth., and aspen Populus tremula L. Thermal analysis of wood samples was carried out under oxidative (air and inert (argon atmospheres from 25 to 700 °С at heating rates 10, 20, 40 °С • min–1 (TG/DTG and from 25 to 590 °С at heating rates 10, 40 °С • min–1 (DSC. The stages of thermal decomposition, the temperature intervals, the mass loss, the mass loss rate, the temperature of DTG/DSC peaks, and heating effects were determined for each tree species. The kinetic thermal degradation parameters of wood were obtained by the Broido and Ozawa–Flynn–Wall models. The wood of coniferous and deciduous species of Siberia was characterized on the base of analysis of activation energy values at various stages of thermal decomposition and the relations of activation energy on conversion level of wood substance of different tree species, and also the comparison of mass loss at the same stages of thermal destruction, heating effects, residual mass and other parameters of TG/DTG, DSC. In our opinion, the results of this work present interest for researchers and specialists in the field of forest pyrology, wood science, dendrochemistry.

Hybrid quantum-classical master equations

International Nuclear Information System (INIS)

Diósi, Lajos

2014-01-01

We discuss hybrid master equations of composite systems, which are hybrids of classical and quantum subsystems. A fairly general form of hybrid master equations is suggested. Its consistency is derived from the consistency of Lindblad quantum master equations. We emphasize that quantum measurement is a natural example of exact hybrid systems. We derive a heuristic hybrid master equation of time-continuous position measurement (monitoring). (paper)

Mesoscale hybrid calibration artifact

Science.gov (United States)

Tran, Hy D.; Claudet, Andre A.; Oliver, Andrew D.

2010-09-07

A mesoscale calibration artifact, also called a hybrid artifact, suitable for hybrid dimensional measurement and the method for make the artifact. The hybrid artifact has structural characteristics that make it suitable for dimensional measurement in both vision-based systems and touch-probe-based systems. The hybrid artifact employs the intersection of bulk-micromachined planes to fabricate edges that are sharp to the nanometer level and intersecting planes with crystal-lattice-defined angles.

Hybrid Action Systems

DEFF Research Database (Denmark)

Ronkko, Mauno; Ravn, Anders P.

1997-01-01

a differential action, which allows differential equations as primitive actions. The extension allows us to model hybrid systems with both continuous and discrete behaviour. The main result of this paper is an extension of such a hybrid action system with parallel composition. The extension does not change...... the original meaning of the parallel composition, and therefore also the ordinary action systems can be composed in parallel with the hybrid action systems....

Hybridization and genome evolution I: The role of contingency during hybrid speciation

Directory of Open Access Journals (Sweden)

Fabrice EROUKHMANOFF, Richard I. BAILEY, Glenn-Peter SæTRE

2013-10-01

Full Text Available Homoploid hybrid speciation (HHS involves the recombination of two differentiated genomes into a novel, functional one without a change in chromosome number. Theoretically, there are numerous ways for two parental genomes to recombine. Hence, chance may play a large role in the formation of a hybrid species. If these genome combinations can evolve rapidly following hybridization and sympatric situations are numerous, recurrent homoploid hybrid speciation is a possibility. We argue that three different, but not mutually exclusive, types of contingencies could influence this process. First, many of these “hopeful monsters” of recombinant parent genotypes would likely have low fitness. Only specific combinations of parental genomic contributions may produce viable, intra-fertile hybrid species able to accommodate potential constraints arising from intragenomic conflict. Second, ecological conditions (competition, geography of the contact zones or the initial frequency of both parent species might favor different outcomes ranging from sympatric coexistence to the formation of hybrid swarms and ultimately hybrid speciation. Finally, history may also play an important role in promoting or constraining recurrent HHS if multiple hybridization events occur sequentially and parental divergence or isolation differs along this continuum. We discuss under which conditions HHS may occur multiple times in parallel and to what extent recombination and selection may fuse the parent genomes in the same or different ways. We conclude by examining different approaches that might help to solve this intriguing evolutionary puzzle [Current Zoology 59 (5: 667-674, 2013].　

Temporal changes of soil physic-chemical properties at different soil depths during larch afforestation by multivariate analysis of covariance.

Science.gov (United States)

Wang, Hui-Mei; Wang, Wen-Jie; Chen, Huanfeng; Zhang, Zhonghua; Mao, Zijun; Zu, Yuan-Gang

2014-04-01

Soil physic-chemical properties differ at different depths; however, differences in afforestation-induced temporal changes at different soil depths are seldom reported. By examining 19 parameters, the temporal changes and their interactions with soil depth in a large chronosequence dataset (159 plots; 636 profiles; 2544 samples) of larch plantations were checked by multivariate analysis of covariance (MANCOVA). No linear temporal changes were found in 9 parameters (N, K, N:P, available forms of N, P, K and ratios of N: available N, P: available P and K: available K), while marked linear changes were found in the rest 10 parameters. Four of them showed divergent temporal changes between surface and deep soils. At surface soils, changing rates were 262.1 g·kg(-1)·year(-1) for SOM, 438.9 mg·g(-1)·year(-1) for C:P, 5.3 mg·g(-1)·year(-1) for C:K, and -3.23 mg·cm(-3)·year(-1) for bulk density, while contrary tendencies were found in deeper soils. These divergences resulted in much moderated or no changes in the overall 80-cm soil profile. The other six parameters showed significant temporal changes for overall 0-80-cm soil profile (P: -4.10 mg·kg(-1)·year(-1); pH: -0.0061 unit·year(-1); C:N: 167.1 mg·g(-1)·year(-1); K:P: 371.5 mg·g(-1) year(-1); N:K: -0.242 mg·g(-1)·year(-1); EC: 0.169 μS·cm(-1)·year(-1)), but without significant differences at different soil depths (P > 0.05). Our findings highlight the importance of deep soils in studying physic-chemical changes of soil properties, and the temporal changes occurred in both surface and deep soils should be fully considered for forest management and soil nutrient balance.

Transformation of soil organic matter in a Japanese larch forest. Radiocarbon and stable carbon isotope compositions versus soil depth

International Nuclear Information System (INIS)

Liu Wei; Moriizumi, Jun; Yamazawa, Hiromi; Iida, Takao

2008-01-01

Soil organic matter at a depth of 0-55 cm, collected from a Japanese larch forest area, was separated into particulate organic matter (size >53 μm), particulate organic matter (size 14 C and δ 13 C values were determined. The Δ 14 C values of particulate matters decreased greatly from 128 per mille to -278 per mille, indicating a relative increase of resistant organic components in particulate matters. That of humic acid matter decreased from 183 per mille to -139 per mille. For these of organic matter fractions at the same depth, the Δ 14 C values of particulate matter (size >53μm) are smallest and those of humic acid matter are the largest. That indicates that a high contribution of young organic matter to the humic acid matter exists and transformation tendency of particulate matter may be from coarse to small in the particulate size. Positive Δ 14 C values appeared at a depth of 10 cm, 25 cm, and 35 cm for the particulate organic matter (size >53μm), particulate organic matter (size 14 C values of the humic acid matter also infects that the bomb carbon has reached the depth of 35 cm. Additionally, the Δ 14 C values of these three kinds of organic matters ranged from 50 per mille to 183 per mille at a depth of 0-7 cm, which were not smaller than that of litter in the forest area, indicating high proportion of modern, plants-derived soil organic matter in this depth ranges. The δ 13 C values increased from -28 per mille to -23 per mille with the increase depth of 0-55 cm. The δ 13 C values of humic acid matter are approximately less than that of particulate matters at the same depth, which may be explained as a high contribution of young organic matter to the humic acid matter. (author)

Electrical potential-assisted DNA hybridization. How to mitigate electrostatics for surface DNA hybridization.

Science.gov (United States)

Tymoczko, Jakub; Schuhmann, Wolfgang; Gebala, Magdalena

2014-12-24

Surface-confined DNA hybridization reactions are sensitive to the number and identity of DNA capture probes and experimental conditions such as the nature and the ionic strength of the electrolyte solution. When the surface probe density is high or the concentration of bulk ions is much lower than the concentration of ions within the DNA layer, hybridization is significantly slowed down or does not proceed at all. However, high-density DNA monolayers are attractive for designing high-sensitivity DNA sensors. Thus, circumventing sluggish DNA hybridization on such interfaces allows a high surface concentration of target DNA and improved signal/noise ratio. We present potential-assisted hybridization as a strategy in which an external voltage is applied to the ssDNA-modified interface during the hybridization process. Results show that a significant enhancement of hybridization can be achieved using this approach.

First-Order Hybrid Logic

DEFF Research Database (Denmark)

Braüner, Torben

2011-01-01

Hybrid logic is an extension of modal logic which allows us to refer explicitly to points of the model in the syntax of formulas. It is easy to justify interest in hybrid logic on applied grounds, with the usefulness of the additional expressive power. For example, when reasoning about time one...... often wants to build up a series of assertions about what happens at a particular instant, and standard modal formalisms do not allow this. What is less obvious is that the route hybrid logic takes to overcome this problem often actually improves the behaviour of the underlying modal formalism....... For example, it becomes far simpler to formulate proof-systems for hybrid logic, and completeness results can be proved of a generality that is simply not available in modal logic. That is, hybridization is a systematic way of remedying a number of known deficiencies of modal logic. First-order hybrid logic...

Research on Hybrid Vehicle Drivetrain

Science.gov (United States)

Xie, Zhongzhi

Hybrid cars as a solution to energy saving, emission reduction measures, have received widespread attention. Motor drive system as an important part of the hybrid vehicles as an important object of study. Based on the hybrid electric vehicle powertrain control system for permanent magnet synchronous motor as the object of study. Can be applied to hybrid car compares the characteristics of traction motors, chose permanent magnet synchronous Motors as drive motors for hybrid vehicles. Building applications in hybrid cars in MATLAB/Simulink simulation model of permanent-magnet synchronous motor speed control system and analysis of simulation results.

Managing hybrid marketing systems.

Science.gov (United States)

Moriarty, R T; Moran, U

1990-01-01

As competition increases and costs become critical, companies that once went to market only one way are adding new channels and using new methods - creating hybrid marketing systems. These hybrid marketing systems hold the promise of greater coverage and reduced costs. But they are also hard to manage; they inevitably raise questions of conflict and control: conflict because marketing units compete for customers; control because new indirect channels are less subject to management authority. Hard as they are to manage, however, hybrid marketing systems promise to become the dominant design, replacing the "purebred" channel strategy in all kinds of businesses. The trick to managing the hybrid is to analyze tasks and channels within and across a marketing system. A map - the hybrid grid - can help managers make sense of their hybrid system. What the chart reveals is that channels are not the basic building blocks of a marketing system; marketing tasks are. The hybrid grid forces managers to consider various combinations of channels and tasks that will optimize both cost and coverage. Managing conflict is also an important element of a successful hybrid system. Managers should first acknowledge the inevitability of conflict. Then they should move to bound it by creating guidelines that spell out which customers to serve through which methods. Finally, a marketing and sales productivity (MSP) system, consisting of a central marketing database, can act as the central nervous system of a hybrid marketing system, helping managers create customized channels and service for specific customer segments.

Genome reorganization in Nicotiana asymmetric somatic hybrids analysed by in situ hybridization

International Nuclear Information System (INIS)

Parokonny, A.S.; Kenton, A.Y.; Gleba, Y.Y.; Bennett, M.D.

1992-01-01

In situ hybridization was used to examine genome reorganization in asymmetric somatic hybrids between Nicotiana plumbaginifolia and Nicotiana sylvestris obtained by fusion of gamma-irradiated protoplasts from one of the parents (donor) with non-irradiated protoplasts from the other (recipient). Probing with biotinylated total genomic DNA from either the donor or the recipient species unequivocally identified genetic material from both parents in 31 regenerant plants, each originating from a different nuclear hybrid colony. This method, termed genomic in situ hybridization (GISH), allowed intergenomic translocations containing chromosome segments from both species to be recognized in four regenerants. A probe homologous to the consensus sequence of the Arabidopsis thaliana telomeric repeat (5'-TTTAGGG-3')n, identified telomeres on all chromosomes, including 'mini-chromosomes' originating from the irradiated donor genome. Genomic in situ hybridization to plant chromosomes provides a rapid and reliable means of screening for recombinant genotypes in asymmetric somatic hybrids. Used in combination with other DNA probes, it also contributes to a greater understanding of the events responsible for genomic recovery and restabilization following genetic manipulation in vitro

Hybrid vehicle potential assessment. Volume 7: Hybrid vehicle review

Science.gov (United States)

Leschly, K. O.

1979-01-01

Review of hybrid vehicles built during the past ten years or planned to be built in the near future is presented. An attempt is made to classify and analyze these vehicles to get an overall picture of their key characteristics. The review includes onroad hybrid passenger cars, trucks, vans, and buses.

Generation of auroral kilometric radiation in upper hybrid wave-lower hybrid soliton interaction

International Nuclear Information System (INIS)

Pottelette, R.; Dubouloz, N.; Treumann, R.A.

1992-01-01

Sporadic bursts of auroral kilometric radiation (AKR) associated with strong bursty electrostatic turbulence in the vicinity of the lower hybrid frequency have been frequently recorded in the AKR source region by the Viking satellite. The variation time scale of these emissions is typically 1 s, long enough for lower hybrid waves to grow to amplitudes of several hundred millivolts per meter and to evolve nonlinearly into solitons. On the basis on these observations it is suggested that formation of lower hybrid solitons may play a role in the generation of AKR. A theoretical model is proposed which is based on the direct acceleration of electrons in the combined lower hybrid soliton and upper hybrid wave fields. The solitons act as sporadic, localized antennas allowing for efficient conversions of the electrostatic energy stored in upper hybrid waves into electromagnetic radiation at a frequency above the X mode cutoff. Excitation of lower hybrid waves is due to the presence of energetic electron beams in the auroral zone found to be associated with steep plasma density gradients. Upper hybrid waves can be excited by a population of energetic electrons with loss cone distributions. The power of the electromagnetic radiation obtained is only noticeable in regions where the plasma frequency is less than the electron gyrofrequency. The theory predicts spectral power densities of the order of 10 -11 to 10 -9 W m -2 Hz -1 in the source region, in good agreement with the Viking observations. The sporadic nature of the radiation derives from lower hybrid soliton collapses which occur on ∼1-s time scales

Craniomandibular form and body size variation of first generation mouse hybrids: A model for hominin hybridization.

Science.gov (United States)

Warren, Kerryn A; Ritzman, Terrence B; Humphreys, Robyn A; Percival, Christopher J; Hallgrímsson, Benedikt; Ackermann, Rebecca Rogers

2018-03-01

Hybridization occurs in a number of mammalian lineages, including among primate taxa. Analyses of ancient genomes have shown that hybridization between our lineage and other archaic hominins in Eurasia occurred numerous times in the past. However, we still have limited empirical data on what a hybrid skeleton looks like, or how to spot patterns of hybridization among fossils for which there are no genetic data. Here we use experimental mouse models to supplement previous studies of primates. We characterize size and shape variation in the cranium and mandible of three wild-derived inbred mouse strains and their first generation (F 1 ) hybrids. The three parent taxa in our analysis represent lineages that diverged over approximately the same period as the human/Neanderthal/Denisovan lineages and their hybrids are variably successful in the wild. Comparisons of body size, as quantified by long bone measurements, are also presented to determine whether the identified phenotypic effects of hybridization are localized to the cranium or represent overall body size changes. The results indicate that hybrid cranial and mandibular sizes, as well as limb length, exceed that of the parent taxa in all cases. All three F 1 hybrid crosses display similar patterns of size and form variation. These results are generally consistent with earlier studies on primates and other mammals, suggesting that the effects of hybridization may be similar across very different scenarios of hybridization, including different levels of hybrid fitness. This paper serves to supplement previous studies aimed at identifying F 1 hybrids in the fossil record and to introduce further research that will explore hybrid morphologies using mice as a proxy for better understanding hybridization in the hominin fossil record. Copyright © 2017 Elsevier Ltd. All rights reserved.

Course on hybrid calculation

International Nuclear Information System (INIS)

Weill, J.; Tellier; Bonnemay; Craigne; Chareton; Di Falco

1969-02-01

After a definition of hybrid calculation (combination of analogue and digital calculation) with a distinction between series and parallel hybrid computing, and a description of a hybrid computer structure and of task sharing between computers, this course proposes a description of hybrid hardware used in Saclay and Cadarache computing centres, and of operations performed by these systems. The next part addresses issues related to programming languages and software. The fourth part describes how a problem is organised for its processing on these computers. Methods of hybrid analysis are then addressed: resolution of optimisation problems, of partial differential equations, and of integral equations by means of different methods (gradient, maximum principle, characteristics, functional approximation, time slicing, Monte Carlo, Neumann iteration, Fischer iteration)

Hydraulic Hybrid Vehicles

Science.gov (United States)

EPA and the United Parcel Service (UPS) have developed a hydraulic hybrid delivery vehicle to explore and demonstrate the environmental benefits of the hydraulic hybrid for urban pick-up and delivery fleets.

Mirror hybrid reactor optimization studies

International Nuclear Information System (INIS)

Bender, D.J.

1976-01-01

A system model of the mirror hybrid reactor has been developed. The major components of the model include (1) the reactor description, (2) a capital cost analysis, (3) various fuel management schemes, and (4) an economic analysis that includes the hybrid plus its associated fission burner reactors. The results presented describe the optimization of the mirror hybrid reactor, the objective being to minimize the cost of electricity from the hybrid fission-burner reactor complex. We have examined hybrid reactors with two types of blankets, one containing natural uranium, the other thorium. The major difference between the two optimized reactors is that the uranium hybrid is a significant net electrical power producer, whereas the thorium hybrid just about breaks even on electrical power. Our projected costs for fissile fuel production are approximately 50 $/g for 239 Pu and approximately 125 $/g for 233 U

Comments On Clock Models In Hybrid Automata And Hybrid Control Systems

Directory of Open Access Journals (Sweden)

Virginia Ecaterina OLTEAN

2001-12-01

Full Text Available Hybrid systems have received a lot of attention in the past decade and a number of different models have been proposed in order to establish mathematical framework that is able to handle both continuous and discrete aspects. This contribution is focused on two models: hybrid automata and hybrid control systems with continuous-discrete interface and the importance of clock models is emphasized. Simple and relevant examples, some taken from the literature, accompany the presentation.

Hybrid Bloch brane

Energy Technology Data Exchange (ETDEWEB)

Bazeia, D.; Lima, Elisama E.M.; Losano, L. [Universidade Federal da Paraiba, Departamento de Fisica, Joao Pessoa, PB (Brazil)

2017-02-15

This work reports on models described by two real scalar fields coupled with gravity in the five-dimensional spacetime, with a warped geometry involving one infinite extra dimension. Through a mechanism that smoothly changes a thick brane into a hybrid brane, one investigates the appearance of hybrid branes hosting internal structure, characterized by the splitting on the energy density and the volcano potential, induced by the parameter which controls interactions between the two scalar fields. In particular, we investigate distinct symmetric and asymmetric hybrid brane scenarios. (orig.)

Gonad morphogenesis defects drive hybrid male sterility in asymmetric hybrid breakdown of Caenorhabditis nematodes.

Science.gov (United States)

Dey, Alivia; Jin, Qi; Chen, Yen-Chu; Cutter, Asher D

2014-01-01

Determining the causes and evolution of reproductive barriers to gene flow between populations, speciation, is the key to understanding the origin of diversity in nature. Many species manifest hybrid breakdown when they intercross, characterized by increasingly exacerbated problems in later generations of hybrids. Recently, Caenorhabditis nematodes have emerged as a genetic model for studying speciation, and here we investigate the nature and causes of hybrid breakdown between Caenorhabditis remanei and C. latens. We quantify partial F1 hybrid inviability and extensive F2 hybrid inviability; the ~75% F2 embryonic arrest occurs primarily during gastrulation or embryonic elongation. Moreover, F1 hybrid males exhibit Haldane's rule asymmetrically for both sterility and inviability, being strongest when C. remanei serves as maternal parent. We show that the mechanism by which sterile hybrid males are incapable of transferring sperm or a copulatory plug involves defective gonad morphogenesis, which we hypothesize results from linker cell defects in migration and/or cell death during development. This first documented case of partial hybrid male sterility in Caenorhabditis follows expectations of Darwin's corollary to Haldane's rule for asymmetric male fitness, providing a powerful foundation for molecular dissection of intrinsic reproductive barriers and divergence of genetic pathways controlling organ morphogenesis. © 2014 Wiley Periodicals, Inc.

An annotated bibliography of scientific literature on research and management activities conducted in Coram Experimental Forest

Science.gov (United States)

Ilana Abrahamson; Katie Lyon

2012-01-01

The Coram Experimental Forest represents western larch-mixed conifer forests of the Northern Rockies. Western larch research was centered at Coram Experimental Forest (CEF) to provide a scientific basis to regenerate and grow this important and valuable species. For example, the long-term silvicultural studies installed at CEF are allowing researchers and managers to...

New hybrid systems

International Nuclear Information System (INIS)

Bernardin, B.

2001-01-01

New hybrid systems are made up of a subcritical core, a spallation target and a proton accelerator. The neutrons that are produced in the target by the flux of protons are necessary to maintain the chain reaction of fission. Some parameters that are important for a classical nuclear reactor like doppler coefficient or delayed neutron fraction do not matter in a hybrid system. In a PWR-type reactor or in a fast reactor the concentration of actinides has a bad impact on these 2 parameters, so it is justified to study hybrid systems as actinide transmuters. The hybrid system, because of its external source of neutrons can put aside an important reactivity margin. This reactivity margin can be used to design safer nuclear reactors (particularly in some situations of reactivity accidents) or to irradiate fuel elements containing high concentrations of minor actinides that could not be allowed in a classical reactor. This article reviews various ways of integrating hybrid systems in a population of already existing nuclear reactors in order to manage quantities of plutonium, of minor actinides or of long-life fission products. (A.C.)

Epitaxial growth of hybrid nanostructures

Science.gov (United States)

Tan, Chaoliang; Chen, Junze; Wu, Xue-Jun; Zhang, Hua

2018-02-01

Hybrid nanostructures are a class of materials that are typically composed of two or more different components, in which each component has at least one dimension on the nanoscale. The rational design and controlled synthesis of hybrid nanostructures are of great importance in enabling the fine tuning of their properties and functions. Epitaxial growth is a promising approach to the controlled synthesis of hybrid nanostructures with desired structures, crystal phases, exposed facets and/or interfaces. This Review provides a critical summary of the state of the art in the field of epitaxial growth of hybrid nanostructures. We discuss the historical development, architectures and compositions, epitaxy methods, characterization techniques and advantages of epitaxial hybrid nanostructures. Finally, we provide insight into future research directions in this area, which include the epitaxial growth of hybrid nanostructures from a wider range of materials, the study of the underlying mechanism and determining the role of epitaxial growth in influencing the properties and application performance of hybrid nanostructures.

Hybrid laser-arc welding

DEFF Research Database (Denmark)

Hybrid laser-arc welding (HLAW) is a combination of laser welding with arc welding that overcomes many of the shortfalls of both processes. This important book gives a comprehensive account of hybrid laser-arc welding technology and applications. The first part of the book reviews...... the characteristics of the process, including the properties of joints produced by hybrid laser-arc welding and ways of assessing weld quality. Part II discusses applications of the process to such metals as magnesium alloys, aluminium and steel as well as the use of hybrid laser-arc welding in such sectors as ship...... building and the automotive industry. With its distinguished editor and international team of contributors, Hybrid laser-arc welding, will be a valuable source of reference for all those using this important welding technology. Professor Flemming Ove Olsen works in the Department of Manufacturing...

Hybrid quantum information processing

Energy Technology Data Exchange (ETDEWEB)

Furusawa, Akira [Department of Applied Physics, School of Engineering, The University of Tokyo (Japan)

2014-12-04

I will briefly explain the definition and advantage of hybrid quantum information processing, which is hybridization of qubit and continuous-variable technologies. The final goal would be realization of universal gate sets both for qubit and continuous-variable quantum information processing with the hybrid technologies. For that purpose, qubit teleportation with a continuousvariable teleporter is one of the most important ingredients.

HYBRID VEHICLE CONTROL SYSTEM

Directory of Open Access Journals (Sweden)

V. Dvadnenko

2016-06-01

Full Text Available The hybrid vehicle control system includes a start–stop system for an internal combustion engine. The system works in a hybrid mode and normal vehicle operation. To simplify the start–stop system, there were user new possibilities of a hybrid car, which appeared after the conversion. Results of the circuit design of the proposed system of basic blocks are analyzed.

Techno-economic comparison of series hybrid, plug-in hybrid, fuel cell and regular cars

NARCIS (Netherlands)

van Vliet, O.P.R.|info:eu-repo/dai/nl/288519361; Kruithof, T.; Turkenburg, W.C.|info:eu-repo/dai/nl/073416355; Faaij, A.P.C.|info:eu-repo/dai/nl/10685903X

2010-01-01

We examine the competitiveness of series hybrid compared to fuel cell, parallel hybrid, and regular cars. We use public domain data to determine efficiency, fuel consumption, total costs of ownership and greenhouse gas emissions resulting from drivetrain choices. The series hybrid drivetrain can be

The Hybrid Advantage: Graduate Student Perspectives of Hybrid Education Courses

Science.gov (United States)

Hall, Sarah; Villareal, Donna

2015-01-01

Hybrid courses combine online and face-to-face learning environments. To organize and teach hybrid courses, instructors must understand the uses of multiple online learning tools and face-toface classroom activities to promote and monitor the progress of students. The purpose of this phenomenological study was to explore the perspectives of…

Optimal Design for Hybrid Ratio of Carbon/Basalt Hybrid Fiber Reinforced Resin Matrix Composites

Directory of Open Access Journals (Sweden)

XU Hong

2017-08-01

Full Text Available The optimum hybrid ratio range of carbon/basalt hybrid fiber reinforced resin composites was studied. Hybrid fiber composites with nine different hybrid ratios were prepared before tensile test.According to the structural features of plain weave, the unit cell's performance parameters were calculated. Finite element model was established by using SHELL181 in ANSYS. The simulated values of the sample stiffness in the model were approximately similar to the experimental ones. The stress nephogram shows that there is a critical hybrid ratio which divides the failure mechanism of HFRP into single failure state and multiple failure state. The tensile modulus, strength and limit tensile strain of HFRP with 45% resin are simulated by finite element method. The result shows that the tensile modulus of HFRP with 60% hybrid ratio increases by 93.4% compared with basalt fiber composites (BFRP, and the limit tensile strain increases by 11.3% compared with carbon fiber composites(CFRP.

Regeneration of Silver fir (Abies Alba Mill. on Clear-cut Areas

Directory of Open Access Journals (Sweden)

Petr Vaněk

2014-01-01

Full Text Available The paper evaluates the growth of Silver fir plantations on clear-cut areas in the regime of different sheltering and mixing with the European larch. The experiment was carried out on a permanent research plot where Silver fir was planted on an unsheltered open space, on an open space sheltered by the gradually overgrowing European larch, alternating in rows and mixed within the row with the gradually overgrowing European larch. It was also planted in a SW corner of the clear-cut area sheltered on two sides by a mature spruce stand. Results of measurements demonstrated that the conditions of the unsheltered clear-cut area or only partly sheltered clear-cut area have no principal adverse influence on the growth of Silver fir. However, a considerably higher mortality, more severe frost injury and impaired vitality of plants were observed. The most suitable option for the regeneration of Silver fir on a clear-cut area, i.e. the option in which Silver fir individuals would exhibit good growth, low mortality, low frost injury and high vitality (needle length and colour appeared to be the plantation of Silver fir in mixed rows with the European larch (N-S direction of rows, where the larch starts to overgrow the fir very rapidly, thus providing the necessary shelter. Pure fir groups are then recommended to be planted in marginal stand parts that are sheltered for a greater part of the day by the surrounding stand.

Secondary formation of oxalic acid and related organic species from biogenic sources in a larch forest at the northern slope of Mt. Fuji

Science.gov (United States)

Mochizuki, Tomoki; Kawamura, Kimitaka; Miyazaki, Yuzo; Wada, Ryuichi; Takahashi, Yoshiyuki; Saigusa, Nobuko; Tani, Akira

2017-10-01

To better understand the formation of water-soluble organic aerosols in the forest atmosphere, we measured low molecular weight (LMW) dicarboxylic acids, oxocarboxylic acids, α-dicarbonyls, unsaturated fatty acids (UFAs), and water-soluble organic carbon (WSOC) in aerosols from a Larix kaempferi forest located at the northern slope of Mt. Fuji, Japan, in summer 2012. Concentrations of dicarboxylic acids, oxocarboxylic acids, α-dicarbonyls, and WSOC showed maxima in daytime. Relative abundance of oxalic acid in LMW dicarboxylic acids was on average 52% and its average concentration was 214 ng m-3. We found that diurnal and temporal variations of oxalic acid are different from those of isoprene and α-pinene, whereas biogenic secondary organic aerosols (BSOAs) derived from isoprene and α-pinene showed similar variations with oxalic acid. The mass concentration ratios of oxalic acid/BSOAs were relatively constant, although a large variation in the concentrations of toluene that is an anthropogenic volatile organic compound was observed. These results suggest that formation of oxalic acid is associated with the oxidation of isoprene and α-pinene with O3 and other oxidants in the forest atmosphere. In addition, concentrations of UFAs were observed, for the first time, to decrease dramatically during daytime in the forest. Mass concentration ratios of azelaic acid to UFAs showed a positive correlation with O3, suggesting that UFAs are oxidized to yield azelaic acid, which may be further decomposed to oxalic acid in the forest atmosphere. We found that contributions of oxalic acid to WSOC are significantly high ranging from 3.7 to 9.7% (average 6.0%). This study demonstrates that forest ecosystem is an important source of oxalic acid and other dicarboxylic acids in the atmosphere.

Hybridization in geese

NARCIS (Netherlands)

Ottenburghs, Jente; Hooft, van Pim; Wieren, van Sipke E.; Ydenberg, Ronald C.; Prins, Herbert H.T.

2016-01-01

The high incidence of hybridization in waterfowl (ducks, geese and swans) makes this bird group an excellent study system to answer questions related to the evolution and maintenance of species boundaries. However, knowledge on waterfowl hybridization is biased towards ducks, with a large

Hybrid Shipboard Microgrids

DEFF Research Database (Denmark)

Othman @ Marzuki, Muzaidi Bin; Anvari-Moghaddam, Amjad; Guerrero, Josep M.

2017-01-01

Strict regulation on emissions of air pollutants imposed by the maritime authorities has led to the introduction of hybrid microgrids to the shipboard power systems (SPSs) which acts toward energy efficient ships with less pollution. A hybrid energy system can include different means of generation...

Isolation and characterization of essential oils from the cones of Norway spruce (Picea abies Karst.), European larch (Larix decidua Mill.) and Scots pine (Pinus sylvestris L.)

OpenAIRE

Zule, Janja; Tišler, Vesna; Žurej, Andrej; Torelli, Niko

2003-01-01

Les dernières évolutions de l’Internet se sont traduites par l’émergence de nouvelles applications distribuées et par la multiplication des technologies réseaux (sans fils, mobiles. . . ) ainsi que des services offerts par les opérateurs sur de nouveaux types de terminaux (portable, PDA. . . ). L’enjeu socio économique majeur de ces avancées est le futur Internet ambiant, à la fois ubiquitaire et intelligent, au travers duquel l’utilisateur pourra, quelle que soit sa localisation ...

Effect of sample storage time on detection of hybridization signals in Checkerboard DNA-DNA hybridization.

Science.gov (United States)

do Nascimento, Cássio; Muller, Katia; Sato, Sandra; Albuquerque Junior, Rubens Ferreira

2012-04-01

Long-term sample storage can affect the intensity of the hybridization signals provided by molecular diagnostic methods that use chemiluminescent detection. The aim of this study was to evaluate the effect of different storage times on the hybridization signals of 13 bacterial species detected by the Checkerboard DNA-DNA hybridization method using whole-genomic DNA probes. Ninety-six subgingival biofilm samples were collected from 36 healthy subjects, and the intensity of hybridization signals was evaluated at 4 different time periods: (1) immediately after collecting (n = 24) and (2) after storage at -20 °C for 6 months (n = 24), (3) for 12 months (n = 24), and (4) for 24 months (n = 24). The intensity of hybridization signals obtained from groups 1 and 2 were significantly higher than in the other groups (p  0.05). The Checkerboard DNA-DNA hybridization method was suitable to detect hybridization signals from all groups evaluated, and the intensity of signals decreased significantly after long periods of sample storage.

Hybrid radiator cooling system

Science.gov (United States)

France, David M.; Smith, David S.; Yu, Wenhua; Routbort, Jules L.

2016-03-15

A method and hybrid radiator-cooling apparatus for implementing enhanced radiator-cooling are provided. The hybrid radiator-cooling apparatus includes an air-side finned surface for air cooling; an elongated vertically extending surface extending outwardly from the air-side finned surface on a downstream air-side of the hybrid radiator; and a water supply for selectively providing evaporative cooling with water flow by gravity on the elongated vertically extending surface.

Hybrid quantum computation

International Nuclear Information System (INIS)

Sehrawat, Arun; Englert, Berthold-Georg; Zemann, Daniel

2011-01-01

We present a hybrid model of the unitary-evolution-based quantum computation model and the measurement-based quantum computation model. In the hybrid model, part of a quantum circuit is simulated by unitary evolution and the rest by measurements on star graph states, thereby combining the advantages of the two standard quantum computation models. In the hybrid model, a complicated unitary gate under simulation is decomposed in terms of a sequence of single-qubit operations, the controlled-z gates, and multiqubit rotations around the z axis. Every single-qubit and the controlled-z gate are realized by a respective unitary evolution, and every multiqubit rotation is executed by a single measurement on a required star graph state. The classical information processing in our model requires only an information flow vector and propagation matrices. We provide the implementation of multicontrol gates in the hybrid model. They are very useful for implementing Grover's search algorithm, which is studied as an illustrative example.

Security in hybrid cloud computing

OpenAIRE

Koudelka, Ondřej

2016-01-01

This bachelor thesis deals with the area of hybrid cloud computing, specifically with its security. The major aim of the thesis is to analyze and compare the chosen hybrid cloud providers. For the minor aim this thesis compares the security challenges of hybrid cloud as opponent to other deployment models. In order to accomplish said aims, this thesis defines the terms cloud computing and hybrid cloud computing in its theoretical part. Furthermore the security challenges for cloud computing a...

Hybrid intermediaries

OpenAIRE

Cetorelli, Nicola

2014-01-01

I introduce the concept of hybrid intermediaries: financial conglomerates that control a multiplicity of entity types active in the "assembly line" process of modern financial intermediation, a system that has become known as shadow banking. The complex bank holding companies of today are the best example of hybrid intermediaries, but I argue that financial firms from the "nonbank" space can just as easily evolve into conglomerates with similar organizational structure, thus acquiring the cap...

Hybrid Ventilation Air Flow Process

DEFF Research Database (Denmark)

Heiselberg, Per Kvols

The scope of this annex is therefore to obtain better knowledge of the use of hybrid ventilation technologies. The annex focus on development of control strategies for hybrid ventilation, on development of methods to predict hybrid ventilation performance in office buildings and on implementation...

Compositional Modelling of Stochastic Hybrid Systems

NARCIS (Netherlands)

Strubbe, S.N.

2005-01-01

In this thesis we present a modelling framework for compositional modelling of stochastic hybrid systems. Hybrid systems consist of a combination of continuous and discrete dynamics. The state space of a hybrid system is hybrid in the sense that it consists of a continuous component and a discrete

Genomic Prediction of Barley Hybrid Performance

Directory of Open Access Journals (Sweden)

Norman Philipp

2016-07-01

Full Text Available Hybrid breeding in barley ( L. offers great opportunities to accelerate the rate of genetic improvement and to boost yield stability. A crucial requirement consists of the efficient selection of superior hybrid combinations. We used comprehensive phenotypic and genomic data from a commercial breeding program with the goal of examining the potential to predict the hybrid performances. The phenotypic data were comprised of replicated grain yield trials for 385 two-way and 408 three-way hybrids evaluated in up to 47 environments. The parental lines were genotyped using a 3k single nucleotide polymorphism (SNP array based on an Illumina Infinium assay. We implemented ridge regression best linear unbiased prediction modeling for additive and dominance effects and evaluated the prediction ability using five-fold cross validations. The prediction ability of hybrid performances based on general combining ability (GCA effects was moderate, amounting to 0.56 and 0.48 for two- and three-way hybrids, respectively. The potential of GCA-based hybrid prediction requires that both parental components have been evaluated in a hybrid background. This is not necessary for genomic prediction for which we also observed moderate cross-validated prediction abilities of 0.51 and 0.58 for two- and three-way hybrids, respectively. This exemplifies the potential of genomic prediction in hybrid barley. Interestingly, prediction ability using the two-way hybrids as training population and the three-way hybrids as test population or vice versa was low, presumably, because of the different genetic makeup of the parental source populations. Consequently, further research is needed to optimize genomic prediction approaches combining different source populations in barley.

Nanoscale Organic Hybrid Electrolytes

KAUST Repository

Nugent, Jennifer L.

2010-08-20

Nanoscale organic hybrid electrolytes are composed of organic-inorganic hybrid nanostructures, each with a metal oxide or metallic nanoparticle core densely grafted with an ion-conducting polyethylene glycol corona - doped with lithium salt. These materials form novel solvent-free hybrid electrolytes that are particle-rich, soft glasses at room temperature; yet manifest high ionic conductivity and good electrochemical stability above 5V. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nanoscale Organic Hybrid Electrolytes

KAUST Repository

Nugent, Jennifer L.; Moganty, Surya S.; Archer, Lynden A.

2010-01-01

Nanoscale organic hybrid electrolytes are composed of organic-inorganic hybrid nanostructures, each with a metal oxide or metallic nanoparticle core densely grafted with an ion-conducting polyethylene glycol corona - doped with lithium salt. These materials form novel solvent-free hybrid electrolytes that are particle-rich, soft glasses at room temperature; yet manifest high ionic conductivity and good electrochemical stability above 5V. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Optimal control of hybrid vehicles

CERN Document Server

Jager, Bram; Kessels, John

2013-01-01

Optimal Control of Hybrid Vehicles provides a description of power train control for hybrid vehicles. The background, environmental motivation and control challenges associated with hybrid vehicles are introduced. The text includes mathematical models for all relevant components in the hybrid power train. The power split problem in hybrid power trains is formally described and several numerical solutions detailed, including dynamic programming and a novel solution for state-constrained optimal control problems based on Pontryagin’s maximum principle.   Real-time-implementable strategies that can approximate the optimal solution closely are dealt with in depth. Several approaches are discussed and compared, including a state-of-the-art strategy which is adaptive for vehicle conditions like velocity and mass. Two case studies are included in the book: ·        a control strategy for a micro-hybrid power train; and ·        experimental results obtained with a real-time strategy implemented in...

Hybrid solar lighting distribution systems and components

Science.gov (United States)

Muhs, Jeffrey D [Lenoir City, TN; Earl, Dennis D [Knoxville, TN; Beshears, David L [Knoxville, TN; Maxey, Lonnie C [Powell, TN; Jordan, John K [Oak Ridge, TN; Lind, Randall F [Lenoir City, TN

2011-07-05

A hybrid solar lighting distribution system and components having at least one hybrid solar concentrator, at least one fiber receiver, at least one hybrid luminaire, and a light distribution system operably connected to each hybrid solar concentrator and each hybrid luminaire. A controller operates all components.

PV-hybrid and mini-grid

Energy Technology Data Exchange (ETDEWEB)

NONE

2010-07-01

Within the 5th European PV-hybrid and mini-grid conference 29th and 30th April, 2010 in Tarragona (Spain) the following lectures were held: (1) Overview of IEA PVPS Task 11 PV-hybrid systems within mini grids; (2) Photovoltaic revolution for deployment in developing countries; (3) Legal and financial conditions for the sustainable operation of mini-grids; (4) EU instruments to promote renewable energies in developing countries; (5) PV hybridization of diesel electricity generators: Conditions of profitability and examples in differential power and storage size ranges; (6) Education suit of designing PV hybrid systems; (7) Sustainable renewable energy projects for intelligent rural electrification in Laos, Cambodia and Vietnam; (8) Techno-economic feasibility of energy supply of remote villages in Palestine by PV systems, diesel generators and electric grid (Case studies: Emnazeil and Atouf villages); (9) Technical, economical and sustainability considerations of a solar PV mini grid as a tool for rural electrification in Uganda; (10) Can we rate inverters for rural electrification on the basis of energy efficiency?; (11) Test procedures for MPPT charge controllers characterization; (12) Energy storage for mini-grid stabilization; (13) Redox flow batteries - Already an alternative storage solution for hybrid PV mini-grids?; (14) Control methods for PV hybrid mini-grids; (15) Partial AC-coupling in mini-grids; (15) Normative issues of small wind turbines in PV hybrid systems; (16) Communication solutions for PV hybrid systems; (17) Towards flexible control and communication of mini-grids; (18) PV/methanol fuel cell hybrid system for powering a highway security variable message board; (19) Polygeneration smartgrids: A solution for the supply of electricity, potable water and hydrogen as fuel for transportation in remote Areas; (20) Implementation of the Bronsbergen micro grid using FACDS; (21) A revisited approach for the design of PV wind hybrid systems; (22

Plug-In Hybrid Electric Vehicle Basics | NREL

Science.gov (United States)

Plug-In Hybrid Electric Vehicle Basics Plug-In Hybrid Electric Vehicle Basics Imagine being able to one that's in a standard hybrid electric vehicle. The larger battery pack allows plug-in hybrids to between fill-ups) that's very similar to the range of a conventional vehicle. A plug-in hybrid vehicle's

Hybridization and management of oak populations

Science.gov (United States)

Oliver Gailing

2017-01-01

Hybridization can result in the transfer of adaptations among species and may contribute to speciation processes. On the other hand, hybridization can also result in a loss of species diversity due to asymmetric gene flow between species (genetic swamping) and in low hybrid fitness. An understanding of the outcomes of interspecific hybridization is crucial for the...

Variations of Climate-Growth Response of Major Conifers at Upper Distributional Limits in Shika Snow Mountain, Northwestern Yunnan Plateau, China

Directory of Open Access Journals (Sweden)

Yun Zhang

2017-10-01

Full Text Available Improved understanding of climate-growth relationships of multiple species is fundamental to understanding and predicting the response of forest growth to future climate change. Forests are mainly composed of conifers in Northwestern Yunnan Plateau, but variations of growth response to climate conditions among the species are not well understood. To detect the growth response of multiple species to climate change, we developed residual chronologies of four major conifers, i.e., George’s fir (Abies georgei Orr, Likiang spruce (Picea likiangensis (Franch. E.Pritz., Gaoshan pine (Pinus densata Mast. and Chinese larch (Larix potaninii Batalin at the upper distributional limits in Shika Snow Mountain. Using the dendroclimatology method, we analyzed correlations between the residual chronologies and climate variables. The results showed that conifer radial growth was influenced by both temperature and precipitation in Shika Snow Mountain. Previous November temperature, previous July temperature, and current May precipitation were the common climatic factors that had consistent influences on radial growth of the four species. Temperature in the previous post-growing season (September–October and moisture conditions in the current growing season (June–August were the common climatic factors that had divergent impacts on the radial growth of the four species. Based on the predictions of climate models and our understanding of the growth response of four species to climate variables, we may understand the growth response to climate change at the species level. It is difficult to predict future forest growth in the study area, since future climate change might cause both increases and decreases for the four species and indirect effects of climate change on forests should be considered.

Recent expansion of erect shrubs in the Low Arctic: evidence from Eastern Nunavik

International Nuclear Information System (INIS)

Tremblay, Benoît; Lévesque, Esther; Boudreau, Stéphane

2012-01-01

In order to characterize shrub response near the treeline in Eastern Nunavik (Québec), a region under extensive warming since the 1990s, we compared two series (1964 and 2003) of vertical aerial photos from the vicinity of Kangiqsualujjuaq. Our study revealed a widespread increase in erect woody vegetation cover. During the 40 years spanning the two photo series, erect shrub and tree cover increased markedly on more than half of the land surface available for new colonization or infilling. Within the 7.2 km 2 analysed, areas with dense shrub and tree cover (>90%) increased from 34% to 44% whereas areas with low cover (<10%) shrank from 45% to 29%. This increase in cover of trees and shrubs occurred throughout the landscape regardless of altitude, slope angle and exposure, although to varying extents. The main shrub species involved in this increase was Betula glandulosa Michx. (dwarf birch), which was present in 98% and dominant in 85% of the 345 plots. In addition, numerous seedlings and saplings of Larix laricina (Du Roi) K Koch (eastern larch) were found above the treeline (25% of the plots), suggesting that the altitudinal treeline might shift upslope in the near future. Sites that remained devoid of erect woody vegetation in 2003 were either characterized by the absence of a suitable seedbed or by harsh local microclimatic conditions (wind exposure or excessive drainage). Our results indicate dramatic increases in shrub and tree cover at a Low Arctic site in Eastern Nunavik, contributing to a growing number of observations of woody vegetation change from various areas around the North. (letter)

Comparison of the Effect of New Spice Freon Extracts Towards Ground Spices and Antioxidants for Improving the Quality of Bulgarian-Type Dry-Cured Sausage

Directory of Open Access Journals (Sweden)

Balev Dessislav Kostadinov

2017-03-01

Full Text Available Ground spices are a source of hazards for dry-fermented meat products. Since dry-cured sausages are not subjected to heat treatment, there is a high risk of microbial cross-contamination and physical impurities. The aim of this study was to determine effects of the replacement of 3 g/kg of ground black pepper (Piper nigrum L., and cumin (Cuminum cyminum with their aliquots of new freon extracts, and compare them with the effect of 0.2 g/kg antioxidant addition (taxifolin extract from Siberian larch (Larix sibirica Ledeb, rosemary (Rosmarinus officinalis L. extract, and butylated hydroxytoluene on sensory properties, color stability, proximate composition, free amino nitrogen and pH of Bulgarian-type dry-cured „Sudjuk“ sausages. The replacement of natural ground spices with aliquots of their extracts improved sensory properties and stabilized the color characteristics of the final product during 30 days of storage at 0–4°C. The addition of 0.2 g/kg rosemary extract was as effective as the addition of freon extracts on the overall assessment to the 14th day of the experiment. It was determined that the addition of antioxidants or spice extracts had no significant effect on proximate composition, pH, and free amino nitrogen accumulation of the “Sudjuk”. The addition of 0.2 g/kg, taxifolin or rosemary extracts and butylated hydroxytoluene was not so efficient in improving the sensory properties and color stabilization in comparison to the new freon spice extracts. The examined spice extracts can be successfully used to improve the quality of “Sudjuk” sausages.

Evaluation of Climate Change in northeastern China by means of d13C in tree-rings in the Great Xiang'An mountains region

Science.gov (United States)

Zhang, Qiqin; Lopez Caceres, Maximo Larry; Sugimoto, Atsuko; Wang, Xiaochun; Liu, Binhui

2017-04-01

The northeastern forest region of China represents one of the southern boundary of the Asian boreal forest and also represents the boundary between humid- semi humid area and arid- semi arid area of China. These forests are mainly dominated by larch (Larix gmelinii) stands with small areas covered by birch and pine forests. Increases in air temperature and precipitation caused by climate change are expected to have a great effect on forest ecosystems boundaries. Accordingly, from 1963-2006, air temperature has increased 1.5℃ in this region. Tree-ring chronologies are commonly used as indicator of climate changes and in recent decades the combination with carbon stable isotopes has shown a higher resolution in the results. Since this combine technique has not been used in northeastern China, we applied this combined technique to reconstruct the climate in the Great Xing'an mountains of northeastern China. Preliminary results showed that tree growth has increased in the middle and southernmost site in the last century while in the northernmost site it decreased for the same period which is in agreement with the mean air temperature increase from south to north in this region under negligible changes in precipitation regime. In contrast, tree-ring δ13C shows a gradual but steady increase along the three sites selected for our study, however the highest being observed in the middle site which experience the largest increased in air temperature in the last decade. This appears to indicate that increases in air temperature produced a stress in the stomatal conductance that so far has translated into tree ring growth decline.

PRESERVING THE QUALITY AND PROLONGATION THE SHELF-LIFE OF BEEF PACKED UNDER VACUUM OR MODIFIED ATMOSPHERE USING TERNARY ANTIOXIDANT BLEND

Directory of Open Access Journals (Sweden)

Alexander Stoyanov Staykov

2016-06-01

Full Text Available Keeping the quality and prolongation the shelf-life of stored at 0  0.5ºC packed under vacuum or modified (80%О2/20%СО2 atmosphere beef m. semimembranosus sprayed with 0.02% solution, containing 10 g.l-1 dihydroquercetin from Siberian larch (Larix sibirica Ledeb, 5 g.l-1 rosemary (Rosmarinus officinalis extract and 1 g.l-1 L-ascorbic acid was studied. The experiments were carried out with five samples: control - air packaged; vacuum packaged; vacuum packaged and treated with 0.02% ternary antioxidant blend; packaged under modified atmosphere (80%O2/20%CO2; and packaged under rich in oxygen modified atmosphere, after spaying with 0.02% ternary antioxidant blend. Samples were stored 28 days (to 32 d post mortem at 0  0.5ºC. The pre-treatment of beef with ternary antioxidant blend preserve the sensory scores and colour properties of beef, and inhibited total microbial growth, and development of Brochothrix termosphacta and pathogens to the end of storage (28 d at 0  0.5ºC, was found. The pre-treatment of beef with ternary antioxidant blend was not main factors which can affect the pH and free amino nitrogen changes in fresh beef. The pre-treatment of beef with 0.02% ternary antioxidant blend may be successfully used for preserving the quality and prolonging the shelf-life of beef m. semimembranosus packed under modified (80%О2/20%СО2 atmosphere. The shelf-life can extend with 75% compared to air packed meat, and with 7 days against only vacuum- or modified atmosphere packed beef.

Hydrothermal stability of silica, hybrid silica and Zr-doped hybrid silica membranes

NARCIS (Netherlands)

ten Hove, Marcel; Luiten-Olieman, Mieke W.J.; Huiskes, Cindy; Nijmeijer, Arian; Winnubst, Louis

2017-01-01

Hybrid silica membranes have demonstrated to possess a remarkable hydrothermal stability in pervaporation and gas separation processes allowing them to be used in industrial applications. In several publications the hydrothermal stability of pure silica or that of hybrid silica membranes are

Editorial: Hybrid Systems

DEFF Research Database (Denmark)

Olderog, Ernst-Rüdiger; Ravn, Anders Peter

2007-01-01

An introduction to three papers in a special issue on Hybrid Systems. These paper were first presented at an IFIP WG 2.2 meeting in Skagen 2005.......An introduction to three papers in a special issue on Hybrid Systems. These paper were first presented at an IFIP WG 2.2 meeting in Skagen 2005....

The situation of hybrid vehicles in Japan; Le point sur les vehicules hybrides au Japon

Energy Technology Data Exchange (ETDEWEB)

Perran, Th.

2000-01-01

Among the different competitors of the race on hybrid vehicles development, Honda was the fastest with its Insight model presented in November 1, 1999. This mass production hybrid vehicle can reach performances of 35 km/l. This new record could be obtained thanks to the development of more efficient weak mixture internal combustion engines and to the lightening of vehicles thanks to the massive use of aluminium. Today, each Japanese car manufacturer has his own hybrid vehicle prototype and one can expect a wave of performing hybrid vehicles on the automotive market in 2001. Toyota remains at the top with its second model, the future 6 places HV-M4 model which will be the very first four wheel drive mono-space hybrid vehicle. (J.S.)

Contrasting development of declining and living larch-spruce stands after a disturbance event: A case study from the High Tatra Mts.

Directory of Open Access Journals (Sweden)

Šebeň Vladimír

2015-09-01

Full Text Available The decline of spruce stands caused by bark beetle outbreaks is a serious economic and ecological problem of forestry in Slovakia. In the preceding period, the decline affected mainly secondary spruce forests. Over the last decade, due to large bark-beetle outbreaks this problem has been observed also in natural spruce forests, even at high elevations. We dealt with this issue in a case study of short-term development of larch-spruce stands in the High Tatras (at a site called Štart. We compared the situation in the stand infested by bark beetles several years after the wind-throw in 2004 with the stand unaffected by bark beetles. We separately analysed the development of the mature (parent stands and the regeneration. The results indicated that forest decline caused by bark beetles significantly depended on the stand structure (mainly tree species composition, which affected the period of stand disintegration. Mortality of spruce trees slowed down biomass accumulation (and thus carbon sequestration in the forest ecosystem. In the new stand, pioneer tree species dominated (in the conditions of the High Tatras it is primarily rowan, although their share in the parent stand was negligible. The results showed different trends in the accumulation of below-ground and above-ground biomass in the declined and living stands. In the first years after the stand decline, rowan accumulated significantly more biomass than the main tree species, i.e. spruce. The reverse situation was under the surviving stand, where spruce trees accumulated more biomass than rowan. The different share of spruce and pioneer tree species, mainly rowan, affected the ratio between fixed (in woody parts of trees and rotating (in foliage carbon in the undergrowth. Forest die-back is a big source of carbon emissions from dead individuals, and the compensation of these losses in the form of carbon sequestration by future stands is a matter of several decades.

Russia and hybrid warfare: identifying critical elements in successful applications of hybrid tactics

OpenAIRE

Neville, Seth B.

2015-01-01

Approved for public release; distribution is unlimited With the Russian annexation of Crimea in 2014, hybrid war became a buzzword within political and academic circles. This thesis examines hybrid warfare applications using contemporary and historical examples. The analysis seeks to determine why a country was or was not successful in its execution of hybrid war, and it assesses the geo-political context of cost, benefit, and risk for an aggressor state contributing to its decision to eng...

Genetic incompatibility dampens hybrid fertility more than hybrid viability: yeast as a case study.

Directory of Open Access Journals (Sweden)

Meibo Xu

Full Text Available Genetic incompatibility is believed to be the major cause of postzygotic reproductive isolation. Despite huge efforts seeking for speciation-related incompatibilities in the past several decades, a general understanding of how genetic incompatibility evolves in affecting hybrid fitness is not available, primarily due to the fact that the number of known incompatibilities is small. Instead of further mapping specific incompatible genes, in this paper we aimed to know the overall effects of incompatibility on fertility and viability, the two aspects of fitness, by examining 89 gametes produced by yeast S. cerevisiae-S. paradoxus F1 hybrids. Homozygous F2 hybrids formed by autodiploidization of F1 gametes were subject to tests for growth rate and sporulation efficiency. We observed much stronger defects in sporulation than in clonal growth for every single F2 hybrid strain, indicating that genetic incompatibility affects hybrid fertility more than hybrid viability in yeast. We related this finding in part to the fast-evolving nature of meiosis-related genes, and proposed that the generally low expression levels of these genes might be a cause of the observation.

Mirror fusion--fission hybrids

International Nuclear Information System (INIS)

Lee, J.D.

1978-01-01

The fusion-fission concept and the mirror fusion-fission hybrid program are outlined. Magnetic mirror fusion drivers and blankets for hybrid reactors are discussed. Results of system analyses are presented and a reference design is described

Triplex in-situ hybridization

Science.gov (United States)

Fresco, Jacques R.; Johnson, Marion D.

2002-01-01

Disclosed are methods for detecting in situ the presence of a target sequence in a substantially double-stranded nucleic acid segment, which comprises: a) contacting in situ under conditions suitable for hybridization a substantially double-stranded nucleic acid segment with a detectable third strand, said third strand being capable of hybridizing to at least a portion of the target sequence to form a triple-stranded structure, if said target sequence is present; and b) detecting whether hybridization between the third strand and the target sequence has occured.

Hybrid electric vehicles TOPTEC

Energy Technology Data Exchange (ETDEWEB)

NONE

1994-06-21

This one-day TOPTEC session began with an overview of hybrid electric vehicle technology. Updates were given on alternative types of energy storage, APU control for low emissions, simulation programs, and industry and government activities. The keynote speech was about battery technology, a key element to the success of hybrids. The TOPEC concluded with a panel discussion on the mission of hybrid electric vehicles, with a perspective from industry and government experts from United States and Canada on their view of the role of this technology.

Hydraulic Hybrid Vehicle Publications | Transportation Research | NREL

Science.gov (United States)

Hydraulic Hybrid Vehicle Publications Hydraulic Hybrid Vehicle Publications The following technical papers and fact sheets provide information about NREL's hydraulic hybrid fleet vehicle evaluations . Refuse Trucks Project Startup: Evaluating the Performance of Hydraulic Hybrid Refuse Vehicles. Bob

Overview of hybrid electric vehicle trend

Science.gov (United States)

Wang, Haomiao; Yang, Weidong; Chen, Yingshu; Wang, Yun

2018-04-01

With the increase of per capita energy consumption, environmental pollution is worsening. Using new alternative sources of energy, reducing the use of conventional fuel-powered engines is imperative. Due to the short period, pure electric vehicles cannot be mass-produced and there are many problems such as imperfect charging facilities. Therefore, the development of hybrid electric vehicles is particularly important in a certain period. In this paper, the classification of hybrid vehicle, research status of hybrid vehicle and future development trends of hybrid vehicles is introduced. It is conducive to the public understanding of hybrid electric vehicles, which has a certain theoretical significance.

Laser driven fusion fission hybrids

International Nuclear Information System (INIS)

Hansen, L.F.; Maniscalco, J.A.

1977-11-01

The role of the fusion-fission hybrid reactor (FFHR) as a fissile fuel and/or power producer is discussed. As long range options to supply the world energy needs, hybrid-fueled thermal-burner reactors are compared to liquid metal fast breeder reactors (LMFBR). A discussion of different fuel cycles (thorium, depleted uranium, and spent fuel) is presented in order to compare the energy multiplication, the production of fissile fuel, the laser efficiency and pellet gain requirements of the hybrid reactor. Lawrence Livermore Laboratory (LLL) has collaborated with Bechtel Corporation and with Westinghouse in two engineering design studies of laser fusion driven hybrid power plants. The hybrid designs which have resulted from these two studies are briefly described and analyzed by considering operational parameters, such as energy multiplication, power density, burn-up and plutonium production as a function time

Genomic and transcriptomic alterations following intergeneric hybridization and polyploidization in the Chrysanthemum nankingense×Tanacetum vulgare hybrid and allopolyploid (Asteraceae).

Science.gov (United States)

Qi, Xiangyu; Wang, Haibin; Song, Aiping; Jiang, Jiafu; Chen, Sumei; Chen, Fadi

2018-01-01

Allopolyploid formation involves two major events: interspecific hybridization and polyploidization. A number of species in the Asteraceae family are polyploids because of frequent hybridization. The effects of hybridization on genomics and transcriptomics in Chrysanthemum nankingense×Tanacetum vulgare hybrids have been reported. In this study, we obtained allopolyploids by applying a colchicine treatment to a synthesized C. nankingense × T. vulgare hybrid. Sequence-related amplified polymorphism (SRAP), methylation-sensitive amplification polymorphism (MSAP), and high-throughput RNA sequencing (RNA-Seq) technologies were used to investigate the genomic, epigenetic, and transcriptomic alterations in both the hybrid and allopolyploids. The genomic alterations in the hybrid and allopolyploids mainly involved the loss of parental fragments and the gain of novel fragments. The DNA methylation level of the hybrid was reduced by hybridization but was restored somewhat after polyploidization. There were more significant differences in gene expression between the hybrid/allopolyploid and the paternal parent than between the hybrid/allopolyploid and the maternal parent. Most differentially expressed genes (DEGs) showed down-regulation in the hybrid/allopolyploid relative to the parents. Among the non-additive genes, transgressive patterns appeared to be dominant, especially repression patterns. Maternal expression dominance was observed specifically for down-regulated genes. Many methylase and methyltransferase genes showed differential expression between the hybrid and parents and between the allopolyploid and parents. Our data indicate that hybridization may be a major factor affecting genomic and transcriptomic changes in newly formed allopolyploids. The formation of allopolyploids may not simply be the sum of hybridization and polyploidization changes but also may be influenced by the interaction between these processes.

Systems for hybrid cars

Science.gov (United States)

Bitsche, Otmar; Gutmann, Guenter

Not only sharp competition but also legislation are pushing development of hybrid drive trains. Based on conventional internal combustion engine (ICE) vehicles, these drive trains offer a wide range of benefits from reduced fuel consumption and emission to multifaceted performance improvements. Hybrid electric drive trains may also facilitate the introduction of fuel cells (FC). The battery is the key component for all hybrid drive trains, as it dominates cost and performance issues. The selection of the right battery technology for the specific automotive application is an important task with an impact on costs of development and use. Safety, power, and high cycle life are a must for all hybrid applications. The greatest pressure to reduce cost is in soft hybrids, where lead-acid embedded in a considerate management presents the cheapest solution, with a considerable improvement in performance needed. From mild to full hybridization, an improvement in specific power makes higher costs more acceptable, provided that the battery's service life is equivalent to the vehicle's lifetime. Today, this is proven for the nickel-metal hydride system. Lithium ion batteries, which make use of a multiple safety concept, and with some development anticipated, provide even better prospects in terms of performance and costs. Also, their scalability permits their application in battery electric vehicles—the basis for better performance and enhanced user acceptance. Development targets for the batteries are discussed with a focus on system aspects such as electrical and thermal management and safety.

Hybrid Management in Hospitals

DEFF Research Database (Denmark)

Byrkjeflot, Haldor; Jespersen, Peter Kragh

2010-01-01

Artiklen indeholder et litteraturbaseret studium af ledelsesformer i sygehuse, hvor sundhedsfaglig ledelse og generel ledelse mikses til hybride ledelsesformer......Artiklen indeholder et litteraturbaseret studium af ledelsesformer i sygehuse, hvor sundhedsfaglig ledelse og generel ledelse mikses til hybride ledelsesformer...

Completeness in Hybrid Type Theory

DEFF Research Database (Denmark)

Areces, Carlos; Blackburn, Patrick Rowan; Huertas, Antonia

2014-01-01

We show that basic hybridization (adding nominals and @ operators) makes it possible to give straightforward Henkin-style completeness proofs even when the modal logic being hybridized is higher-order. The key ideas are to add nominals as expressions of type t, and to extend to arbitrary types th......-style intensional models; we build, as simply as we can, hybrid logicover Henkin’s logic...

A battery-fuel cell hybrid auxiliary power unit for trucks: Analysis of direct and indirect hybrid configurations

International Nuclear Information System (INIS)

Samsun, Remzi Can; Krupp, Carsten; Baltzer, Sidney; Gnörich, Bruno; Peters, Ralf; Stolten, Detlef

2016-01-01

Highlights: • A battery-fuel cell hybrid auxiliary power unit for heavy duty vehicles is reported. • Comparison of direct and indirect hybrids using representative load profiles. • Evaluation based on validated fuel cell system and battery models. • Indirect hybrid with constant fuel cell load yields 29.3% hybrid system efficiency. • Fuel cell should be pre-heated using waste heat from the diesel engine during drive. - Abstract: The idling operation of engines in heavy duty vehicles to cover electricity demand during layovers entails significant fuel consumption and corresponding emissions. Indeed, this mode of operation is highly inefficient and a noteworthy contributor to the transportation sector’s aggregate carbon dioxide emissions. Here, a potential solution to this wasteful practice is outlined in the form of a hybrid battery-fuel cell system for application as an auxiliary power unit for trucks. Drawing on experimentally-validated fuel cell and battery models, several possible hybrid concepts are evaluated and direct and indirect hybrid configurations analyzed using a representative load profile. The results indicate that a direct hybrid configuration is only applicable if the load demand profile does not deviate strongly from the assumed profile. Operation of an indirect hybrid with a constant fuel cell load yields the greatest hybrid system efficiency, at 29.3%, while battery size could be reduced by 87% if the fuel cell is operated at the highest dynamics. Maximum efficiency in truck applications can be achieved by pre-heating the system prior to operation using exhaust heat from the motor, which increased system efficiency from 25.3% to 28.1%, including start-up. These findings confirm that hybrid systems could offer enormous fuel savings and constitute a sizeable step on the path toward energy-efficient and environmentally-friendly heavy duty vehicles that does not necessitate a fuel switch.

Hybrid systems with constraints

CERN Document Server

Daafouz, Jamal; Sigalotti, Mario

2013-01-01

Control theory is the main subject of this title, in particular analysis and control design for hybrid dynamic systems.The notion of hybrid systems offers a strong theoretical and unified framework to cope with the modeling, analysis and control design of systems where both continuous and discrete dynamics interact. The theory of hybrid systems has been the subject of intensive research over the last decade and a large number of diverse and challenging problems have been investigated. Nevertheless, many important mathematical problems remain open.This book is dedicated mainly to

Relative biocompatibility of micro-hybrid and nano-hybrid light-activated composite resins.

Science.gov (United States)

Olabisi Arigbede, Abiodun; Folasade Adeyemi, Bukola; Femi-Akinlosotu, Omowumi

2017-01-01

Background. In vitro studies have revealed a direct association between resin content and cytotoxicity of composite resins; however, implantation studies in this regard are sparse. This study investigates the relationship between filler content of composite resins and biocompatibility. Methods. This research employed twelve 180‒200-gr male Wistar rats, 1 nano-hybrid (Prime-Dent Inc.) and 1 micro-hybrid (Medental Inc.) composite resins containing 74% and 80‒90% filler content, respectively. The samples were assessed on the 2nd, 14th and 90th day of implantation. Four rats were allocated to each day in this experimental study. A section of 1.5mm long cured nano-hybrid and micro-hybrid materials were implanted into the right and left upper and lower limbs of the rats, respectively. Eight samples were generated on each day of observation. Inflammation was graded according to the criteria suggested by Orstavik and Major. Pearson's chi-squared test was employed to determine the relationship between the tissue responses of the two materials. Statistical significance was set at P resin had a score of 3.0 for cellular inflammation. On the 14th day, the micro-hybrid resin also exhibited a lower average grade for cellular inflammation. On the 90th day, the micro-hybrid resin had a higher grade of inflammation (0.9) compared to 0.3 recorded for nano-hybrid. The composite resins with higher filler content elicited a significantly lower grade of inflammation irrespective of the duration (χ=20.000, df=8, P=0.010) while the composite resins with lower filler content elicited a significantly lower inflammatory response on the 90th day (χ=4.000, df=1, P=0.046). Conclusion. The composite resins with higher filler content generally elicited significantly lower grades of inflammation, and the composite resins with lower filler content exhibited significantly lower inflammatory response on the 90th day of implantation.

Hybrid Electric Vehicle Testing | Transportation Research | NREL

Science.gov (United States)

Hybrid Electric Vehicle Evaluations Hybrid Electric Vehicle Evaluations How Hybrid Electric Vehicles Work Hybrid electric vehicles combine a primary power source, an energy storage system, and an is used to propel the vehicle during normal drive cycles. The batteries supply additional power for

Hybrid Electric Vehicle Publications | Transportation Research | NREL

Science.gov (United States)

Hybrid Electric Vehicle Publications Hybrid Electric Vehicle Publications The following technical papers, conference papers, and fact sheets provide information about NREL's hybrid electric fleet vehicle Class 8 Hybrid Electric Delivery Trucks. Mike Lammert. (2011) FedEx Delivery Trucks In-Use and Vehicle

Alternative Fuels Data Center: Hybrid Electric Vehicles

Science.gov (United States)

. A wide variety of hybrid electric vehicle models is currently available. Although HEVs are often -go traffic), further improving fuel economy. Mild hybrid systems cannot power the vehicle using Hybrid Electric Vehicles to someone by E-mail Share Alternative Fuels Data Center: Hybrid Electric

Effects of natural hybrid and non-hybrid Epichloë endophytes on the response of Hordelymus europaeus to drought stress.

Science.gov (United States)

Oberhofer, Martina; Güsewell, Sabine; Leuchtmann, Adrian

2014-01-01

Interspecific hybrid endophytes of the genus Epichloë (Ascomycota, Clavicipitaceae) are prevalent in wild grass populations, possibly because of their larger gene variation, resulting in increased fitness benefits for host plants; however, the reasons are not yet known. We tested hypotheses regarding niche expansion mediated by hybrid endophytes, population-dependent interactions and local co-adaptation in the woodland grass Hordelymus europaeus, which naturally hosts both hybrid and non-hybrid endophyte taxa. Seedlings derived from seeds of four grass populations made endophyte free were re-inoculated with hybrid or non-hybrid endophyte strains, or left endophyte free. Plants were grown in the glasshouse with or without drought treatment. Endophyte infection increased plant biomass and tiller production by 10-15% in both treatments. Endophyte types had similar effects on growth, but opposite effects on reproduction: non-hybrid endophytes increased seed production, whereas hybrid endophytes reduced or prevented it completely. The results are consistent with the observation that non-hybrid endophytes in H. europaeus prevail at dry sites, but cannot explain the prevalence of hybrid endophytes. Thus, our results do not support the hypothesis of niche expansion of hybrid-infected plants. Moreover, plants inoculated with native relative to foreign endophytes yielded higher infections, but both showed similar growth and survival, suggesting weak co-adaptation. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

Mechanical and thermal design of hybrid blankets

International Nuclear Information System (INIS)

Schultz, K.R.

1978-01-01

The thermal and mechanical aspects of hybrid reactor blanket design considerations are discussed. This paper is intended as a companion to that of J. D. Lee of Lawrence Livermore Laboratory on the nuclear aspects of hybrid reactor blanket design. The major design characteristics of hybrid reactor blankets are discussed with emphasis on the areas of difference between hybrid reactors and standard fusion or fission reactors. Specific examples are used to illustrate the design tradeoffs and choices that must be made in hybrid reactor design. These examples are drawn from the work on the Mirror Hybrid Reactor

Deriving simulators for hybrid Chi models

NARCIS (Netherlands)

Beek, van D.A.; Man, K.L.; Reniers, M.A.; Rooda, J.E.; Schiffelers, R.R.H.

2006-01-01

The hybrid Chi language is formalism for modeling, simulation and verification of hybrid systems. The formal semantics of hybrid Chi allows the definition of provably correct implementations for simulation, verification and realtime control. This paper discusses the principles of deriving an

Hybrid Universities in Malaysia

Science.gov (United States)

Lee, Molly; Wan, Chang Da; Sirat, Morshidi

2017-01-01

Are Asian universities different from those in Western countries? Premised on the hypothesis that Asian universities are different because of hybridization between Western academic models and local traditional cultures, this paper investigates the hybrid characteristics in Malaysian universities resulting from interaction between contemporary…

Battery control system for hybrid vehicle and method for controlling a hybrid vehicle battery

Science.gov (United States)

Bockelmann, Thomas R [Battle Creek, MI; Hope, Mark E [Marshall, MI; Zou, Zhanjiang [Battle Creek, MI; Kang, Xiaosong [Battle Creek, MI

2009-02-10

A battery control system for hybrid vehicle includes a hybrid powertrain battery, a vehicle accessory battery, and a prime mover driven generator adapted to charge the vehicle accessory battery. A detecting arrangement is configured to monitor the vehicle accessory battery's state of charge. A controller is configured to activate the prime mover to drive the generator and recharge the vehicle accessory battery in response to the vehicle accessory battery's state of charge falling below a first predetermined level, or transfer electrical power from the hybrid powertrain battery to the vehicle accessory battery in response to the vehicle accessory battery's state of charge falling below a second predetermined level. The invention further includes a method for controlling a hybrid vehicle powertrain system.

A hybrid air conditioner driven by a hybrid solar collector

Science.gov (United States)

Al-Alili, Ali

The objective of this thesis is to search for an efficient way of utilizing solar energy in air conditioning applications. The current solar Air Conditioners (A/C)s suffer from low Coefficient of Performance (COP) and performance degradation in hot and humid climates. By investigating the possible ways of utilizing solar energy in air conditioning applications, the bottlenecks in these approaches were identified. That resulted in proposing a novel system whose subsystem synergy led to a COP higher than unity. The proposed system was found to maintain indoor comfort at a higher COP compared to the most common solar A/Cs, especially under very hot and humid climate conditions. The novelty of the proposed A/C is to use a concentrating photovoltaic/thermal collector, which outputs thermal and electrical energy simultaneously, to drive a hybrid A/C. The performance of the hybrid A/C, which consists of a desiccant wheel, an enthalpy wheel, and a vapor compression cycle (VCC), was investigated experimentally. This work also explored the use of a new type of desiccant material, which can be regenerated with a low temperature heat source. The experimental results showed that the hybrid A/C is more effective than the standalone VCC in maintaining the indoor conditions within the comfort zone. Using the experimental data, the COP of the hybrid A/C driven by a hybrid solar collector was found to be at least double that of the current solar A/Cs. The innovative integration of its subsystems allows each subsystem to do what it can do best. That leads to lower energy consumption which helps reduce the peak electrical loads on electric utilities and reduces the consumer operating cost since less energy is purchased during the on peak periods and less solar collector area is needed. In order for the proposed A/C to become a real alternative to conventional systems, its performance and total cost were optimized using the experimentally validated model. The results showed that for an

Behavioral and spermatogenic hybrid male breakdown in Nasonia.

Science.gov (United States)

Clark, M E; O'Hara, F P; Chawla, A; Werren, J H

2010-03-01

Several reproductive barriers exist within the Nasonia species complex, including allopatry, premating behavioral isolation, postzygotic inviability and Wolbachia-induced cytoplasmic incompatibility. Here we show that hybrid males suffer two additional reproductive disadvantages, an inability to properly court females and decreased sperm production. Hybrid behavioral sterility, characterized by a reduced ability of hybrids to perform necessary courtship behaviors, occurs in hybrids between two species of Nasonia. Hybrid males produced in crosses between N. vitripennis and N. giraulti courted females at a reduced frequency (23-69%), compared with wild-type N. vitripennis and N. giraulti males (>93%). Reduced courtship frequency was not a simple function of inactivity among hybrids. A strong effect of cytoplasmic (mitochondrial) background was also found in N. vitripennis and N. giraulti crosses; F2 hybrids with giraulti cytoplasm showing reduced ability at most stages of courtship. Hybrids produced between a younger species pair, N. giraulti and N. longicornis, were behaviorally fertile. All males possessed motile sperm, but sperm production is greatly reduced in hybrids between the older species pair, N. vitripennis and N. giraulti. This effect on hybrid males, lowered sperm counts rather than nonfunctional sperm, is different from most described cases of hybrid male sterility, and may represent an earlier stage of hybrid sperm breakdown. The results add to previous studies of F2 hybrid inviability and behavioral sterility, and indicate that Wolbachia-induced hybrid incompatibility has arisen early in species divergence, relative to behavioral sterility and spermatogenic infertility.

Behavioural and spermatogenic hybrid male breakdown in Nasonia

Science.gov (United States)

Clark, Michael E.; O’Hara, F. Patrick; Chawla, Ankur; Werren, John H.

2010-01-01

Several reproductive barriers exists within the Nasonia species complex, including allopatry, premating behavioural isolation, postzygotic inviability and Wolbachia-induced cytoplasmic incompatibility. Here we show that hybrid males suffer two additional reproductive disadvantages, an inability to properly court females and decreased sperm production. Hybrid behavioural sterility, characterized by a reduced ability of hybrids to perform necessary courtship behaviours, occurs in hybrids between two species of Nasonia. Hybrid males produced in crosses between N. vitripennis and N. giraulti courted females at a reduced frequency (23-69%), compared to wild-type N. vitripennis and N. giraulti males (>93%). Reduced courtship frequency was not a simple function of inactivity among hybrids. A strong effect of cytoplasmic (mitochondrial) background was also found in N. vitripennis and N. giraulti crosses; F2 hybrids with giraulti cytoplasm showing reduced ability at most stages of courtship. Hybrids produced between a younger species pair, N. giraulti and N. longicornis, were behaviourally fertile. All males possessed motile sperm, but sperm production is greatly reduced in hybrids between the older species pair, N. vitripennis and N. giraulti. This effect on hybrid males, lowered sperm counts rather than non-functional sperm, is different from most described cases of hybrid male sterility and may represent an earlier stage of hybrid sperm breakdown. The results add to previous studies of F2 hybrid inviability and behavioural sterility, and indicated that Wolbachia induced hybrid incompatibility has arisen early in species divergence, relative to behavioural sterility and spermatogenic infertility. PMID:20087395

In situ hybridization at the electron microscope level: hybrid detection by autoradiography and colloidal gold.

Science.gov (United States)

Hutchison, N J; Langer-Safer, P R; Ward, D C; Hamkalo, B A

1982-11-01

In situ hybridization has become a standard method for localizing DNA or RNA sequences in cytological preparations. We developed two methods to extend this technique to the transmission electron microscope level using mouse satellite DNA hybridization to whole mount metaphase chromosomes as the test system. The first method devised is a direct extension of standard light microscope level using mouse satellite DNA hybridization to whole mount metaphase chromosomes as the test system. The first method devised is a direct extension of standard light microscope in situ hybridization. Radioactively labeled complementary RNA (cRNA) is hybridized to metaphase chromosomes deposited on electron microscope grids and fixed in 70 percent ethanol vapor; hybridixation site are detected by autoradiography. Specific and intense labeling of chromosomal centromeric regions is observed even after relatively short exposure times. Inerphase nuclei present in some of the metaphase chromosome preparations also show defined paatterms of satellite DNA labeling which suggests that satellite-containing regions are associate with each other during interphase. The sensitivity of this method is estimated to at least as good as that at the light microscope level while the resolution is improved at least threefold. The second method, which circumvents the use of autoradiogrphic detection, uses biotin-labeled polynucleotide probes. After hybridization of these probes, either DNA or RNA, to fixed chromosomes on grids, hybrids are detected via reaction is improved at least threefold. The second method, which circumvents the use of autoradiographic detection, uses biotin-labeled polynucleotide probes. After hybridization of these probes, either DNA or RNA, to fixed chromosomes on grids, hybrids are detected via reaction with an antibody against biotin and secondary antibody adsorbed to the surface of over centromeric heterochromatin and along the associated peripheral fibers. Labeling is on average

Internal combustion engines in hybrid vehicles

NARCIS (Netherlands)

Mourad, S.; Weijer, C.J.T. van de; Beckman, D.E.

1998-01-01

In this paper the use of internal combustion engines in hybrid powertrains is investigated. The substantial difference between the use of internal combustion engines in conventional and in hybrid vehicles mean that engines for hybrid vehicles should be designed specifically for the purpose. At the

Design Procedure for Hybrid Ventilation

DEFF Research Database (Denmark)

Heiselberg, Per; Tjelflaat, Per Olaf

Mechanical and natural ventilation systems have developed separately during many years. The natural next step in this development is development of ventilation concepts that utilises and combines the best features from each system into a new type of ventilation system - Hybrid Ventilation....... Buildings with hybrid ventilation often include other sustainable technologies and an energy optimisation requires an integrated approach in the design of the building and its mechanical systems. Therefore, the hybrid ventilation design procedure differs from the design procedure for conventional HVAC....... The first ideas on a design procedure for hybrid ventilation is presented and the different types of design methods, that is needed in different phases of the design process, is discussed....

Design, analysis and modeling of a novel hybrid powertrain system based on hybridized automated manual transmission

Science.gov (United States)

Wu, Guang; Dong, Zuomin

2017-09-01

Hybrid electric vehicles are widely accepted as a promising short to mid-term technical solution due to noticeably improved efficiency and lower emissions at competitive costs. In recent years, various hybrid powertrain systems were proposed and implemented based on different types of conventional transmission. Power-split system, including Toyota Hybrid System and Ford Hybrid System, are well-known examples. However, their relatively low torque capacity, and the drive of alternative and more advanced designs encouraged other innovative hybrid system designs. In this work, a new type of hybrid powertrain system based hybridized automated manual transmission (HAMT) is proposed. By using the concept of torque gap filler (TGF), this new hybrid powertrain type has the potential to overcome issue of torque gap during gearshift. The HAMT design (patent pending) is described in details, from gear layout and design of gear ratios (EV mode and HEV mode) to torque paths at different gears. As an analytical tool, mutli-body model of vehicle equipped with this HAMT was built to analyze powertrain dynamics at various steady and transient modes. A gearshift was decomposed and analyzed based basic modes. Furthermore, a Simulink-SimDriveline hybrid vehicle model was built for the new transmission, driveline and vehicle modular. Control strategy has also been built to harmonically coordinate different powertrain components to realize TGF function. A vehicle launch simulation test has been completed under 30% of accelerator pedal position to reveal details during gearshift. Simulation results showed that this HAMT can eliminate most torque gap that has been persistent issue of traditional AMT, improving both drivability and performance. This work demonstrated a new type of transmission that features high torque capacity, high efficiency and improved drivability.

Insight and Evidence Motivating the Simplification of Dual-Analysis Hybrid Systems into Single-Analysis Hybrid Systems

Science.gov (United States)

Todling, Ricardo; Diniz, F. L. R.; Takacs, L. L.; Suarez, M. J.

2018-01-01

Many hybrid data assimilation systems currently used for NWP employ some form of dual-analysis system approach. Typically a hybrid variational analysis is responsible for creating initial conditions for high-resolution forecasts, and an ensemble analysis system is responsible for creating sample perturbations used to form the flow-dependent part of the background error covariance required in the hybrid analysis component. In many of these, the two analysis components employ different methodologies, e.g., variational and ensemble Kalman filter. In such cases, it is not uncommon to have observations treated rather differently between the two analyses components; recentering of the ensemble analysis around the hybrid analysis is used to compensated for such differences. Furthermore, in many cases, the hybrid variational high-resolution system implements some type of four-dimensional approach, whereas the underlying ensemble system relies on a three-dimensional approach, which again introduces discrepancies in the overall system. Connected to these is the expectation that one can reliably estimate observation impact on forecasts issued from hybrid analyses by using an ensemble approach based on the underlying ensemble strategy of dual-analysis systems. Just the realization that the ensemble analysis makes substantially different use of observations as compared to their hybrid counterpart should serve as enough evidence of the implausibility of such expectation. This presentation assembles numerous anecdotal evidence to illustrate the fact that hybrid dual-analysis systems must, at the very minimum, strive for consistent use of the observations in both analysis sub-components. Simpler than that, this work suggests that hybrid systems can reliably be constructed without the need to employ a dual-analysis approach. In practice, the idea of relying on a single analysis system is appealing from a cost-maintenance perspective. More generally, single-analysis systems avoid

Mirror hybrid reactor studies

International Nuclear Information System (INIS)

Bender, D.J.

1978-01-01

The hybrid reactor studies are reviewed. The optimization of the point design and work on a reference design are described. The status of the nuclear analysis of fast spectrum blankets, systems studies for fissile fuel producing hybrid reactor, and the mechanical design of the machine are reviewed

Configurations of hybrid-electric cars propulsion systems

OpenAIRE

Cundev, Dobri; Sarac, Vasilija; Stefanov, Goce

2011-01-01

Over the last few years, hybrid electric cars have taken significant role in automotive market. There are successful technological solutions of hybrid-electric propulsion systems implemented in commercial passenger cars. Every automobile manufacturer of hybrid vehicles has unique hybrid propulsion system. In this paper, all implemented systems are described, analyzed and compared.

Nuclear hybrid energy infrastructure

Energy Technology Data Exchange (ETDEWEB)

Agarwal, Vivek; Tawfik, Magdy S.

2015-02-01

The nuclear hybrid energy concept is becoming a reality for the US energy infrastructure where combinations of the various potential energy sources (nuclear, wind, solar, biomass, and so on) are integrated in a hybrid energy system. This paper focuses on challenges facing a hybrid system with a Small Modular Reactor at its core. The core of the paper will discuss efforts required to develop supervisory control center that collects data, supports decision-making, and serves as an information hub for supervisory control center. Such a center will also be a model for integrating future technologies and controls. In addition, advanced operations research, thermal cycle analysis, energy conversion analysis, control engineering, and human factors engineering will be part of the supervisory control center. Nuclear hybrid energy infrastructure would allow operators to optimize the cost of energy production by providing appropriate means of integrating different energy sources. The data needs to be stored, processed, analyzed, trended, and projected at right time to right operator to integrate different energy sources.

Hybrid synchronization of hyperchaotic Lu system

Indian Academy of Sciences (India)

In this paper, we study the hybrid synchronization between two identical hyperchaotic Lu systems. Hybrid synchronization of hyperchaotic Lu system is achieved through synchronization of two pairs of states and anti-synchronization of the other two pairs of states. Active controls are designed to achieve hybrid ...

Feasibility study on the introduction of hybrid buses; Hybrid bus donyu kanosei chosa

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-03-01

The purpose of this research is to design pilot projects for introducing hybrid buses into the public transportation sector. This research also covers contents regarding hybrid buses with a trolley-collector motor and a diesel engine, to identify technical and economical problems and to analyze cost beneficiation using hybrid buses. The trolley parallel hybrid system has been employed for the feasibility study. This system has abundant operation results in Europe and the USA. Its battery is small or is not necessary, and the maintenance cost is also low. As a result of the feasibility study, reduction effects of CO2 emission were found out. When the CO2 generation at the power plant is not counted, the reduction effect was estimated to be 32% compared with the CO2 emission from diesel buses. When the CO2 generation at the power plant is considered, it was estimated to be 18%. The cost beneficiation was investigated for the cases of the transportations using trolley system surrounding a medium-scale terminal among large-scale housing development, tourist resort, and stations. The annual income is estimated to be larger than the annual payment in each case. It was found that the hybrid bus is economically established. 17 refs., 48 figs., 41 tabs.

Hybrid cryptosystem RSA - CRT optimization and VMPC

Science.gov (United States)

Rahmadani, R.; Mawengkang, H.; Sutarman

2018-03-01

Hybrid cryptosystem combines symmetric algorithms and asymmetric algorithms. This combination utilizes speeds on encryption/decryption processes of symmetric algorithms and asymmetric algorithms to secure symmetric keys. In this paper we propose hybrid cryptosystem that combine symmetric algorithms VMPC and asymmetric algorithms RSA - CRT optimization. RSA - CRT optimization speeds up the decryption process by obtaining plaintext with dp and p key only, so there is no need to perform CRT processes. The VMPC algorithm is more efficient in software implementation and reduces known weaknesses in RC4 key generation. The results show hybrid cryptosystem RSA - CRT optimization and VMPC is faster than hybrid cryptosystem RSA - VMPC and hybrid cryptosystem RSA - CRT - VMPC. Keyword : Cryptography, RSA, RSA - CRT, VMPC, Hybrid Cryptosystem.

Parametric systems analysis for ICF hybrid reactors

International Nuclear Information System (INIS)

Berwald, D.H.; Maniscalco, J.A.; Chapin, D.L.

1981-01-01

Parametric design and systems analysis for inertial confinement fusion-fission hybrids are presented. These results were generated as part of the Electric Power Research Institute (EPRI) sponsored Feasibility Assessment of Fusion-Fission Hybrids, using an Inertial Confinement Fusion (ICF) hybrid power plant design code developed in conjunction with the feasibility assessment. The SYMECON systems analysis code, developed by Westinghouse, was used to generate economic results for symbiotic electricity generation systems consisting of the hybrid and its client Light Water Reactors (LWRs). These results explore the entire fusion parameter space for uranium fast fission blanket hybrids, thorium fast fission blanket hybrids, and thorium suppressed fission blanket types are discussed, and system sensitivities to design uncertainties are explored

Electric/Hybrid Vehicle Simulation

Science.gov (United States)

Slusser, R. A.; Chapman, C. P.; Brennand, J. P.

1985-01-01

ELVEC computer program provides vehicle designer with simulation tool for detailed studies of electric and hybrid vehicle performance and cost. ELVEC simulates performance of user-specified electric or hybrid vehicle under user specified driving schedule profile or operating schedule. ELVEC performs vehicle design and life cycle cost analysis.

Assay of hybrid ribonuclease using a membrane filter-immobilized synthetic hybrid: application to the human leukemic cell

International Nuclear Information System (INIS)

Papaphilis, A.D.; Kamper, E.F.

1985-01-01

A method for assaying hybrid ribonuclease has been devised which utilizes as substrate the synthetic hybrid [ 3 H]polyriboadenylic acid [poly(rA)]:polydeoxythymidylic acid [poly(dT)] immobilized on the solid matrix of nitrocellulose filters. The hybridization on filter of [ 3 H]poly(rA) to poly(dT) has been explored in terms of efficacy of the process and the response of the product to RNase H. A pulse of uv irradiation of poly(dT) while in dry state on the filter increased its firm binding to the filter in a concentration-dependent manner, resulting in a concomitant increase of the yield of hybrid formation. The filter-immobilized hybrid was 95% resistant to RNase A but sensitive to RNase H. When stored in toluene in the cold the hybrid maintained its stability for over 6 months, as judged by its resistance to RNase A. The method offers a number of advantages over assays that use solution hybrids as substrates and was readily applicable in the screening of leukemic patients, in the leukocytes of which it has demonstrated increased RNase H levels

The tokamak hybrid reactor

International Nuclear Information System (INIS)

Kelly, J.L.; Rose, R.P.

1981-01-01

At a time when the potential benefits of various energy options are being seriously evaluated in many countries through-out the world, it is both timely and important to evaluate the practical application of fusion reactors for their economical production of nuclear fissile fuels from fertile fuels. The fusion hybrid reactor represents a concept that could assure the availability of adequate fuel supplies for a proven nuclear technology and have the potential of being an electrical energy source as opposed to an energy consumer as are the present fuel enrichment processes. Westinghouse Fusion Power Systems Department, under Contract No. EG-77-C-02-4544 with the Department of Energy, Office of Fusion Energy, has developed a preliminary conceptual design for an early twenty-first century fusion hybrid reactor called the commercial Tokamak Hybrid Reactor (CTHR). This design was developed as a first generation commercial plant producing fissile fuel to support a significant number of client Light Water Reactor (LWR) Plants. To the depth this study has been performed, no insurmountable technical problems have been identified. The study has provided a basis for reasonable cost estimates of the hybrid plants as well as the hybrid/LWR system busbar electricity costs. This energy system can be optimized to have a net cost of busbar electricity that is equivalent to the conventional LWR plant, yet is not dependent on uranium ore prices or standard enrichment costs, since the fusion hybrid can be fueled by numerous fertile fuel resources. A nearer-term concept is also defined using a beam driven fusion driver in lieu of the longer term ignited operating mode. (orig.)

Evaluation for breeding purposes of SO/sub 2/-induced damage to trees and shrubs

Energy Technology Data Exchange (ETDEWEB)

Bartkowiak, S; Bialobok, S; Rachwal, L

1975-01-01

Experiments were performed to determine the response of trees and shrubs to sulfur dioxide in the vicinity of industrial plants. Studies were carried out in the neighborhood of the factories as well as in exposure chambers in the laboratory. Species investigated were Larix liptolepis, Larix potaninii, Populus simonii, Forsythia intermedia, Ligustrum vulgare, Syringa amurensis and Syringa pekinensis. Injuries ranged from virually undamaged to severe, and there was considerable variation within each genus as well as between individual trees and shrubs.

Towers of hybrid mesons

International Nuclear Information System (INIS)

Semay, Claude; Buisseret, Fabien; Silvestre-Brac, Bernard

2009-01-01

A hybrid meson is a quark-antiquark pair in which, contrary to ordinary mesons, the gluon field is in an excited state. In the framework of constituent models, the interaction potential is assumed to be the energy of an excited string. An approximate, but accurate, analytical solution of the Schroedinger equation with such a potential is presented. When applied to hybrid charmonia and bottomonia, towers of states are predicted in which the masses are a linear function of a harmonic oscillator band number for the quark-antiquark pair. Such a formula could be a reliable guide for the experimental detection of heavy hybrid mesons.

Program Hybrid/GDH. Revision

International Nuclear Information System (INIS)

Blann, M.; Bisplinghoff, J.

1975-10-01

This code is the most recent in a series of codes for doing a-priori pre-equilibrium decay calculations. It has been written to permit the user to exercise many options at time of execution. It will, for example, permit calculation with either Hybrid model or the geometry dependent Hybrid model (GDH). Intranuclear transition rates can be calculated using either a nucleon-nucleon scattering approach (improved over earlier results) or based on the imaginary optical potential. Transition rates based on exciton lifetimes can be selected (as suggested in the Hybrid model formulation) or an average lifetime for each n-exciton configuration may be selected

Hybrid job shop scheduling

NARCIS (Netherlands)

Schutten, Johannes M.J.

1995-01-01

We consider the problem of scheduling jobs in a hybrid job shop. We use the term 'hybrid' to indicate that we consider a lot of extensions of the classic job shop, such as transportation times, multiple resources, and setup times. The Shifting Bottleneck procedure can be generalized to deal with

Diagnoses of hybrid hummingbirds (Aves: Trochilidae). 17. Documentation of the intrageneric hybrid (Archilochus colubris × Archilochus alexandri)

DEFF Research Database (Denmark)

Graves, Gary R.; Dittmann, Donna L.; Cardiff, Steven W.

2016-01-01

Although the breeding ranges of Archilochus alexandri (Black-chinned Hummingbird) and Archilochus colubris (Ruby throated Hummingbird) are narrowly parapatric in central Texas and central and southern Oklahoma, there have been few reports of hybridization in the literature and no well......-documented hybrid specimens. Here we provide a comprehensive assessment of two male hybrids collected, respectively, in Grayson County, Texas, and East Baton Rouge Parish, Louisiana. As has been the pattern in other hummingbird hybrids, both specimens exhibit a blended mosaic of plumage characters of the parental...

Analysis of Non-binary Hybrid LDPC Codes

OpenAIRE

Sassatelli, Lucile; Declercq, David

2008-01-01

In this paper, we analyse asymptotically a new class of LDPC codes called Non-binary Hybrid LDPC codes, which has been recently introduced. We use density evolution techniques to derive a stability condition for hybrid LDPC codes, and prove their threshold behavior. We study this stability condition to conclude on asymptotic advantages of hybrid LDPC codes compared to their non-hybrid counterparts.

Hybrid fission-fusion nuclear reactors

International Nuclear Information System (INIS)

Zucchetti, Massimo

2011-01-01

A fusion-fission hybrid could contribute to all components of nuclear power - fuel supply, electricity production, and waste management. The idea of the fusion-fission hybrid is many decades old. Several ideas, both new and revisited, have been investigated by hybrid proponents. These ideas appear to have attractive features, but they require various levels of advances in plasma science and fusion and nuclear technology. As a first step towards the development of hybrid reactors, fusion neutron sources can be considered as an option. Compact high-field tokamaks can be a candidate for being the neutron source in a fission-fusion hybrid, essentially due to their design characteristics, such as compact dimensions, high magnetic field, flexibility of operation. This study presents the development of a tokamak neutron source for a material testing facility using an Ignitor-based concept. The computed values show the potential of this neutron-rich device for fusion materials testing. Some full-power months of operation are sufficient to obtain relevant radiation damage values in terms of dpa. (Author)

On the complexity of the Saccharomyces bayanus taxon: hybridization and potential hybrid speciation.

Directory of Open Access Journals (Sweden)

Laura Pérez-Través

Full Text Available Although the genus Saccharomyces has been thoroughly studied, some species in the genus has not yet been accurately resolved; an example is S. bayanus, a taxon that includes genetically diverse lineages of pure and hybrid strains. This diversity makes the assignation and classification of strains belonging to this species unclear and controversial. They have been subdivided by some authors into two varieties (bayanus and uvarum, which have been raised to the species level by others. In this work, we evaluate the complexity of 46 different strains included in the S. bayanus taxon by means of PCR-RFLP analysis and by sequencing of 34 gene regions and one mitochondrial gene. Using the sequence data, and based on the S. bayanus var. bayanus reference strain NBRC 1948, a hypothetical pure S. bayanus was reconstructed for these genes that showed alleles with similarity values lower than 97% with the S. bayanus var. uvarum strain CBS 7001, and of 99-100% with the non S. cerevisiae portion in S. pastorianus Weihenstephan 34/70 and with the new species S. eubayanus. Among the S. bayanus strains under study, different levels of homozygosity, hybridization and introgression were found; however, no pure S. bayanus var. bayanus strain was identified. These S. bayanus hybrids can be classified into two types: homozygous (type I and heterozygous hybrids (type II, indicating that they have been originated by different hybridization processes. Therefore, a putative evolutionary scenario involving two different hybridization events between a S. bayanus var. uvarum and unknown European S. eubayanus-like strains can be postulated to explain the genomic diversity observed in our S. bayanus var. bayanus strains.

PV-HYBRID and MINI-GRID. Proceedings

Energy Technology Data Exchange (ETDEWEB)

NONE

2006-07-01

Within the 3rd European Conference at the Centre de Congres in Aix en Provence (France) between 11th and 12th May, 2006, the following lessons were held: (1) Small electric networks: European drivers and projects for the integration of RES and DG into the electricity grids of the future (Manuel Sanchez-Jimenez); (2) PV hybrid system within mini grids - IEA PVPS programme (Meuch Konraf); (3) Renewables for the developing world (Alvaro Ponce Plaza); (4) Rural electicity supply using photovoltaic / - Diesel hybrid systems: Attractive for investors in the renewable energy sector? (Andreas Hahn); (5) Economic analysis of stand-alone and grid-connected photovoltaic systems under current tariff structure of Taiwan (Yaw-Juen Wang); (6) Using wind-PV-diesel hybrid system for electrification of remote village in Western Libya (N.M. Kreama); (7) Venezuela's renewable energy program for small towns and rural areas ''Sembrando Luz'' (Jorge Torres); (8) AeroSmart5, the professional, sysem-compatible small-scale wind energy converter will be tested in field tests (Fabian Jochem); (9) Lifetime, test procedures and recommendations for optimal operating strategies for lead-acid-batteries in renewable energy systems - A survey on results from European projects from the 5th framework programme (Rudi Kaiser); (10) Prototype of a reversible fuel cell system for autonomous power supplies (Tom Smolinska); (11) Interconnection management in microgrids (Michel Vandenbergh); (12) Control strategy for a small-scale stand-alone power system based on renewable energy and hydrogen (Harald Miland); (13) Standard renewable electricity supply for people in rural areas - mini-grids in western provinces of China (Michael Wollny); (14) The Brava island a ''100% renewable energy'' project (Jean-Christian Marcel); (15) Breakthrough to a new era of PV-hybrid systems with the help of standardised components communication? (Michael Mueller); (16) Standardized

Bucking the trend in wolf-dog hybridization: first evidence from europe of hybridization between female dogs and male wolves.

Science.gov (United States)

Hindrikson, Maris; Männil, Peep; Ozolins, Janis; Krzywinski, Andrzej; Saarma, Urmas

2012-01-01

Studies on hybridization have proved critical for understanding key evolutionary processes such as speciation and adaptation. However, from the perspective of conservation, hybridization poses a concern, as it can threaten the integrity and fitness of many wild species, including canids. As a result of habitat fragmentation and extensive hunting pressure, gray wolf (Canis lupus) populations have declined dramatically in Europe and elsewhere during recent centuries. Small and fragmented populations have persisted, but often only in the presence of large numbers of dogs, which increase the potential for hybridization and introgression to deleteriously affect wolf populations. Here, we demonstrate hybridization between wolf and dog populations in Estonia and Latvia, and the role of both genders in the hybridization process, using combined analysis of maternal, paternal and biparental genetic markers. Eight animals exhibiting unusual external characteristics for wolves - six from Estonia and two from Latvia - proved to be wolf-dog hybrids. However, one of the hybridization events was extraordinary. Previous field observations and genetic studies have indicated that mating between wolves and dogs is sexually asymmetrical, occurring predominantly between female wolves and male dogs. While this was also the case among the Estonian hybrids, our data revealed the existence of dog mitochondrial genomes in the Latvian hybrids and, together with Y chromosome and autosomal microsatellite data, thus provided the first evidence from Europe of mating between male wolves and female dogs. We discuss patterns of sexual asymmetry in wolf-dog hybridization.

Sequence-dependent theory of oligonucleotide hybridization kinetics

International Nuclear Information System (INIS)

Marimuthu, Karthikeyan; Chakrabarti, Raj

2014-01-01

A theoretical approach to the prediction of the sequence and temperature-dependent rate constants for oligonucleotide hybridization reactions has been developed based on the theory of relaxation kinetics. One-sided and two-sided melting reaction mechanisms for oligonucleotide hybridization reactions have been considered, analyzed, modified, and compared to select a physically consistent as well as robust model for prediction of the relaxation times of DNA hybridization reactions that agrees with the experimental evidence. The temperature- and sequence-dependent parameters of the proposed model have been estimated using available experimental data. The relaxation time model that we developed has been combined with the nearest neighbor model of hybridization thermodynamics to estimate the temperature- and sequence-dependent rate constants of an oligonucleotide hybridization reaction. The model-predicted rate constants are compared to experimentally determined rate constants for the same oligonucleotide hybridization reactions. Finally, we consider a few important applications of kinetically controlled DNA hybridization reactions

Hybrid intelligent engineering systems

CERN Document Server

Jain, L C; Adelaide, Australia University of

1997-01-01

This book on hybrid intelligent engineering systems is unique, in the sense that it presents the integration of expert systems, neural networks, fuzzy systems, genetic algorithms, and chaos engineering. It shows that these new techniques enhance the capabilities of one another. A number of hybrid systems for solving engineering problems are presented.

Electric-hybrid-vehicle simulation

Science.gov (United States)

Pasma, D. C.

The simulation of electric hybrid vehicles is to be performed using experimental data to model propulsion system components. The performance of an existing ac propulsion system will be used as the baseline for comparative purposes. Hybrid components to be evaluated include electrically and mechanically driven flywheels, and an elastomeric regenerative braking system.

Graphene hybridization for energy storage applications.

Science.gov (United States)

Li, Xianglong; Zhi, Linjie

2018-05-08

Graphene has attracted considerable attention due to its unique two-dimensional structure, high electronic mobility, exceptional thermal conductivity, excellent optical transmittance, good mechanical strength, and ultrahigh surface area. To meet the ever increasing demand for portable electronic products, electric vehicles, smart grids, and renewable energy integrations, hybridizing graphene with various functions and components has been demonstrated to be a versatile and powerful strategy to significantly enhance the performance of various energy storage systems such as lithium-ion batteries, supercapacitors and beyond, because such hybridization can result in synergistic effects that combine the best merits of involved components and confer new functions and properties, thereby improving the charge/discharge efficiencies and capabilities, energy/power densities, and cycle life of these energy storage systems. This review will focus on diverse graphene hybridization principles and strategies for energy storage applications, and the proposed outline is as follows. First, graphene and its fundamental properties, followed by graphene hybrids and related hybridization motivation, are introduced. Second, the developed hybridization formulas of using graphene for lithium-ion batteries are systematically categorized from the viewpoint of material structure design, bulk electrode construction, and material/electrode collaborative engineering; the latest representative progress on anodes and cathodes of lithium-ion batteries will be reviewed following such classifications. Third, similar hybridization formulas for graphene-based supercapacitor electrodes will be summarized and discussed as well. Fourth, the recently emerging hybridization formulas for other graphene-based energy storage devices will be briefed in combination with typical examples. Finally, future prospects and directions on the exploration of graphene hybridization toward the design and construction of

Establishing trees on cut-over peatlands in eastern Canada

Directory of Open Access Journals (Sweden)

J. Bussières

2008-12-01

Full Text Available Four major tree-planting trials on cut-over peatlands in eastern Canada were surveyed in 2002, in order to evaluate the potential use of trees in rehabilitation following horticultural peat extraction. At one of the sites, an experiment to determine the appropriate fertilisation rate for trees planted on cut-over peatlands was also conducted over several years. Tree performance was assessed by measuring survival, total height and annual growth of red maple (Acer rubrum L., tamarack (Larix laricina (Du Roi Koch., black spruce (Picea mariana (Mill. B.S.P., jack pine (Pinus banksiana Lamb. and hybrid poplar (Populus spp.. Establishment and growth of tamarack and black spruce in cut-over peatlands showed good potential when compared to performance in conventional forestry plantations. Red maple and jack pine gave poor productivity but promising survival, whilst hybrid poplar plantings failed. Adding nutrients was essential for growth but dosages above 122.5 g of 3.4N-8.3P-24.2K per tree gave no further improvement. Therefore, several different tree species can be planted to reclaim cut-over peatlands in eastern Canada, so long as the appropriate species are chosen and nutrients are provided.

Interspecific Hybridization within Ornamental Plants

DEFF Research Database (Denmark)

Kuligowska, Katarzyna

commercially important genera of ornamental plants: Kalanchoë and Hibiscus. The nature of hybridization barriers hampering hybrid production was investigated during pre- and post-fertilization stages. For each genus the interspecific crosses of Kalanchoë species and Hibiscus species, abnormal germination...... and growth of pollen tubes, as well as lower frequencies of pollen tubes were observed in specific cross-combinations. Post-fertilization barriers related to endosperm development and hybrid incompatibility were also observed in Kalanchoë and Hibiscus genus, respectively. Qualitative and quantitative...

Spatial sorting promotes the spread of maladaptive hybridization

Science.gov (United States)

Lowe, Winsor H.; Muhlfeld, Clint C.; Allendorf, Fred W.

2015-01-01

Invasive hybridization is causing loss of biodiversity worldwide. The spread of such introgression can occur even when hybrids have reduced Darwinian fitness, which decreases the frequency of hybrids due to low survival or reproduction through time. This paradox can be partially explained by spatial sorting, where genotypes associated with dispersal increase in frequency at the edge of expansion, fueling further expansion and allowing invasive hybrids to increase in frequency through space rather than time. Furthermore, because all progeny of a hybrid will be hybrids (i.e., will possess genes from both parental taxa), nonnative admixture in invaded populations can increase even when most hybrid progeny do not survive. Broader understanding of spatial sorting is needed to protect native biodiversity.

Reactivity limitations on the performance of hybrid reactors

International Nuclear Information System (INIS)

Piera, M.; Martinez-Val, J.M.

1994-01-01

A neutronic theory for characterizing the hybrid blanket physics is used to show that hybrid performances are limited because of reactivity restrictions. The hybrid must always remain subcritical, even in abnormal conditions. For hybrids devoted to energy production by multiplication of the neutron source power, the restriction is particularly strong, and the electricity recirculation fraction to feed the plant can be too large for its economic feasibility. In hybrids used to breed fissile fuel, the power of LWR maintained by power unit of the hybrid is also limited (to a factor of 10, approx.). (author)

Hybrid Arrays for Chemical Sensing

Science.gov (United States)

Kramer, Kirsten E.; Rose-Pehrsson, Susan L.; Johnson, Kevin J.; Minor, Christian P.

In recent years, multisensory approaches to environment monitoring for chemical detection as well as other forms of situational awareness have become increasingly popular. A hybrid sensor is a multimodal system that incorporates several sensing elements and thus produces data that are multivariate in nature and may be significantly increased in complexity compared to data provided by single-sensor systems. Though a hybrid sensor is itself an array, hybrid sensors are often organized into more complex sensing systems through an assortment of network topologies. Part of the reason for the shift to hybrid sensors is due to advancements in sensor technology and computational power available for processing larger amounts of data. There is also ample evidence to support the claim that a multivariate analytical approach is generally superior to univariate measurements because it provides additional redundant and complementary information (Hall, D. L.; Linas, J., Eds., Handbook of Multisensor Data Fusion, CRC, Boca Raton, FL, 2001). However, the benefits of a multisensory approach are not automatically achieved. Interpretation of data from hybrid arrays of sensors requires the analyst to develop an application-specific methodology to optimally fuse the disparate sources of data generated by the hybrid array into useful information characterizing the sample or environment being observed. Consequently, multivariate data analysis techniques such as those employed in the field of chemometrics have become more important in analyzing sensor array data. Depending on the nature of the acquired data, a number of chemometric algorithms may prove useful in the analysis and interpretation of data from hybrid sensor arrays. It is important to note, however, that the challenges posed by the analysis of hybrid sensor array data are not unique to the field of chemical sensing. Applications in electrical and process engineering, remote sensing, medicine, and of course, artificial

Genome-wide mapping in a house mouse hybrid zone reveals hybrid sterility loci and Dobzhansky-Muller interactions.

Science.gov (United States)

Turner, Leslie M; Harr, Bettina

2014-12-09

Mapping hybrid defects in contact zones between incipient species can identify genomic regions contributing to reproductive isolation and reveal genetic mechanisms of speciation. The house mouse features a rare combination of sophisticated genetic tools and natural hybrid zones between subspecies. Male hybrids often show reduced fertility, a common reproductive barrier between incipient species. Laboratory crosses have identified sterility loci, but each encompasses hundreds of genes. We map genetic determinants of testis weight and testis gene expression using offspring of mice captured in a hybrid zone between M. musculus musculus and M. m. domesticus. Many generations of admixture enables high-resolution mapping of loci contributing to these sterility-related phenotypes. We identify complex interactions among sterility loci, suggesting multiple, non-independent genetic incompatibilities contribute to barriers to gene flow in the hybrid zone.

Hybrid soft computing approaches research and applications

CERN Document Server

Dutta, Paramartha; Chakraborty, Susanta

2016-01-01

The book provides a platform for dealing with the flaws and failings of the soft computing paradigm through different manifestations. The different chapters highlight the necessity of the hybrid soft computing methodology in general with emphasis on several application perspectives in particular. Typical examples include (a) Study of Economic Load Dispatch by Various Hybrid Optimization Techniques, (b) An Application of Color Magnetic Resonance Brain Image Segmentation by ParaOptiMUSIG activation Function, (c) Hybrid Rough-PSO Approach in Remote Sensing Imagery Analysis,  (d) A Study and Analysis of Hybrid Intelligent Techniques for Breast Cancer Detection using Breast Thermograms, and (e) Hybridization of 2D-3D Images for Human Face Recognition. The elaborate findings of the chapters enhance the exhibition of the hybrid soft computing paradigm in the field of intelligent computing.

Thermal simulation of a cooling system of hybrid commercial vehicles; Thermalsimulation eine Hybrid-LKW-Kuehlsystems

Energy Technology Data Exchange (ETDEWEB)

Stroh, Christoph; Schnoerch, Stefan; Rathberger, Christian [Magna Powertrain Engineering Center Steyr GmbH und Co. KG, St. Valentin (Austria)

2012-11-01

In the past few years hybrid vehicles have been in the center of automotive engineering efforts, in particular in the field of passenger cars. But hybrid powertrains will also be important for commercial trucks. This focus on hybrid vehicles leads to high demands on thermal management since the additional components in a hybrid vehicle need appropriate cooling or even heating. In the given paper the simulation of a complete cooling system of a hybrid commercial vehicle will be explained. For this virtual examination the commercial 1D thermal management software KULI will be used, a co-simulation with several programs will not be done deliberately. Yet all aspects which are relevant for a global assessment of the thermal management are considered. The main focus is put on the investigation of appropriate concepts for the fluid circuits, including low and high temperature circuits, electric water pumps, etc. Moreover, also a refrigerant circuit with a chiller for active battery cooling will be used, the appropriate control strategy is implemented as well. For simulating transient profiles a simple driving simulation model is included, using road profile, ambient conditions, and various vehicle parameters as input. In addition an engine model is included which enables the investigation of fuel consumption potentials. This simulation model shows how the thermal management of a hybrid vehicle can be investigated with a single program and with reasonable effort. (orig.)

Magnetite Dissolution Performance of HYBRID-II Decontamination Process

International Nuclear Information System (INIS)

Kim, Seonbyeong; Lee, Woosung; Won, Huijun; Moon, Jeikwon; Choi, Wangkyu

2014-01-01

In this study, we conducted the magnetite dissolution performance test of HYBRID-II (Hydrazine Based Reductive metal Ion Decontamination with sulfuric acid) as a part of decontamination process development. Decontamination performance of HYBRID process was successfully tested with the results of the acceptable decontamination factor (DF) in the previous study. While following-up studies such as the decomposition of the post-decontamination HYBRID solution and corrosion compatibility on the substrate metals of the target reactor coolant system have been continued, we also seek for an alternate version of HYBRID process suitable especially for decommissioning. Inspired by the relationship between the radius of reacting ion and the reactivity, we replaced the nitrate ion in HYBRID with bigger sulfate ion to accommodate the dissolution reaction and named HYBRID-II process. As a preliminary step for the decontamination performance, we tested the magnetite dissolution performance of developing HYBRID-II process and compared the results with those of HYBRID process. HYBRID process developed previously is known have the acceptable decontamination performance, but the relatively larger volume of secondary waste induced by anion exchange resin to treat nitrate ion is the one of the problems related in the development of HYBRID process to be applicable. Therefore we alternatively devised HYBRID-II process using sulfuric acid and tested its dissolution of magnetite in numerous conditions. From the results shown in this study, we can conclude that HYBRID-II process improves the decontamination performance and potentially reduces the volume of secondary waste. Rigorous tests with metal oxide coupons obtained from reactor coolant system will be followed to prove the robustness of HYBRID-II process in the future

Current status of hybrid coronary revascularization.

Science.gov (United States)

Jaik, Nikhil P; Umakanthan, Ramanan; Leacche, Marzia; Solenkova, Natalia; Balaguer, Jorge M; Hoff, Steven J; Ball, Stephen K; Zhao, David X; Byrne, John G

2011-10-01

Hybrid coronary revascularization combines coronary artery bypass surgery with percutaneous coronary intervention techniques to treat coronary artery disease. The potential benefits of such a technique are to offer the patients the best available treatments for coronary artery disease while minimizing the risks of the surgery. Hybrid coronary revascularization has resulted in the establishment of new 'hybrid operating suites', which incorporate and integrate the capabilities of a cardiac surgery operating room with that of an interventional cardiology laboratory. Hybrid coronary revascularization has greatly augmented teamwork and cooperation between both fields and has demonstrated encouraging as well as good initial outcomes.

Do Hybrid Trees Inherit Invasive Characteristics? Fruits of Corymbia torelliana X C. citriodora Hybrids and Potential for Seed Dispersal by Bees.

Science.gov (United States)

Wallace, Helen Margaret; Leonhardt, Sara Diana

2015-01-01

Tree invasions have substantial impacts on biodiversity and ecosystem functioning, and trees that are dispersed by animals are more likely to become invasive. In addition, hybridisation between plants is well documented as a source of new weeds, as hybrids gain new characteristics that allow them to become invasive. Corymbia torelliana is an invasive tree with an unusual animal dispersal mechanism: seed dispersal by stingless bees, that hybridizes readily with other species. We examined hybrids between C. torelliana and C. citriodora subsp. citriodora to determine whether hybrids have inherited the seed dispersal characteristics of C. torelliana that allow bee dispersal. Some hybrid fruits displayed the characteristic hollowness, resin production and resin chemistry associated with seed dispersal by bees. However, we did not observe bees foraging on any hybrid fruits until they had been damaged. We conclude that C. torelliana and C. citriodora subsp. citriodora hybrids can inherit some fruit characters that are associated with dispersal by bees, but we did not find a hybrid with the complete set of characters that would enable bee dispersal. However, around 20,000 hybrids have been planted in Australia, and ongoing monitoring is necessary to identify any hybrids that may become invasive.

Principle, function, experiences, hybrid chilled ceilings; Prinzip, Funktion, Erfahrungen. Hybrid-Kuehldecken

Energy Technology Data Exchange (ETDEWEB)

Schulz, Uwe W. [Hochschule Luzern (Switzerland). Technik und Architektur

2010-12-15

Hybrid chilled ceilings combine a radiation chilled ceiling with thermal activations of a concrete ceiling. The activation permits the utilization of alternative and/or small cold generators for the efficient night cooling. The traditional chilled ceiling grants a speedy reaction to load variations as well as a reduction of the reverberation periods. In addition, the combination supplies a draught-free insertion of air. Beside established solutions, MWH Barcol-Air (Staefa, Switzerland) also offers project-specific hybrid chilled ceilings.

Hybrid uncertainty-based design optimization and its application to hybrid rocket motors for manned lunar landing

Directory of Open Access Journals (Sweden)

Hao Zhu

2017-04-01

Full Text Available Design reliability and robustness are getting increasingly important for the general design of aerospace systems with many inherently uncertain design parameters. This paper presents a hybrid uncertainty-based design optimization (UDO method developed from probability theory and interval theory. Most of the uncertain design parameters which have sufficient information or experimental data are classified as random variables using probability theory, while the others are defined as interval variables with interval theory. Then a hybrid uncertainty analysis method based on Monte Carlo simulation and Taylor series interval analysis is developed to obtain the uncertainty propagation from the design parameters to system responses. Three design optimization strategies, including deterministic design optimization (DDO, probabilistic UDO and hybrid UDO, are applied to the conceptual design of a hybrid rocket motor (HRM used as the ascent propulsion system in Apollo lunar module. By comparison, the hybrid UDO is a feasible method and can be effectively applied to the general design of aerospace systems.

Hybrid uncertainty-based design optimization and its application to hybrid rocket motors for manned lunar landing

Institute of Scientific and Technical Information of China (English)

Zhu Hao; Tian Hui; Cai Guobiao

2017-01-01

Design reliability and robustness are getting increasingly important for the general design of aerospace systems with many inherently uncertain design parameters. This paper presents a hybrid uncertainty-based design optimization (UDO) method developed from probability theory and interval theory. Most of the uncertain design parameters which have sufficient information or experimental data are classified as random variables using probability theory, while the others are defined as interval variables with interval theory. Then a hybrid uncertainty analysis method based on Monte Carlo simulation and Taylor series interval analysis is developed to obtain the uncer-tainty propagation from the design parameters to system responses. Three design optimization strategies, including deterministic design optimization (DDO), probabilistic UDO and hybrid UDO, are applied to the conceptual design of a hybrid rocket motor (HRM) used as the ascent propulsion system in Apollo lunar module. By comparison, the hybrid UDO is a feasible method and can be effectively applied to the general design of aerospace systems.

Introgressive hybridization as a promoter of genome reshuffling in natural homoploid fish hybrids (Cyprinidae, Leuciscinae)

Czech Academy of Sciences Publication Activity Database

Pereira, C. S.; Aboim, M. A.; Ráb, Petr; Collares-Pereira, M. J.

2014-01-01

Roč. 112, č. 3 (2014), s. 343-350 ISSN 0018-067X Institutional support: RVO:67985904 Keywords : comparative genome hybridization * hybrid zones * introgression Subject RIV: EG - Zoology Impact factor: 3.805, year: 2014

Close Look at Hybrid Vehicle Loyalty and Ownership

Energy Technology Data Exchange (ETDEWEB)

Hwang, Ho-Ling [ORNL; Chin, Shih-Miao [ORNL; Wilson, Daniel W [ORNL; Oliveira Neto, Francisco Moraes [ORNL; Taylor, Rob D [ORNL

2013-01-01

In a news release dated April 9, 2012, Polk stated that only 35% of hybrid owners bought a hybrid again when they returned to market in 2011. These findings were based on an internal study conducted by Polk. The study also indicated that if repurchase behavior among the high volume audience of Toyota Prius owners wasn t factored in; hybrid loyalty would drop to under 25%. This news release has generated a lot of interest and concern by the automobile industry as well as consumers, since it was published, and caused many to think about the idea of hybrid loyalty as well as factors that influence consumers. Most reactions to the 35% hybrid loyalty dealt with concerns of the viability of hybrid technology as part of the solution to address transportation energy challenges. This paper attempts to shed more light on Polk s hybrid loyalty study as well as explore several information sources concerning hybrid loyalty status. Specifically, major factors that might impact the selection and acquisition of hybrid vehicles are addressed. This includes investigating the associations between hybrid market shares and influencing factors like fuel price and hybrid incentives, as well as the availability of hybrid models and other highly fuel efficient vehicle options. This effort is not in-depth study, but rather a short study to see if Polk s claim could be validated. This study reveals that Polk s claim was rather misleading because its definition of loyalty was very narrow. This paper also suggests that Polk s analysis failed to account for some very important factors, raising the question of whether it is fair to compare a vehicle drive train option (which hybrids are) with a vehicle brand in terms of loyalty and also raises the question of whether hybrid loyalty is even a valid point to consider. This report maintains that Polk s study does not prove that hybrid owners were dissatisfied with their vehicles, which was a common theme among reporting news agencies when Polk

Hydraulic Hybrid Fleet Vehicle Testing | Transportation Research | NREL

Science.gov (United States)

Hydraulic Hybrid Fleet Vehicle Evaluations Hydraulic Hybrid Fleet Vehicle Evaluations How Hydraulic Hybrid Vehicles Work Hydraulic hybrid systems can capture up to 70% of the kinetic energy that would -pressure reservoir to a high-pressure accumulator. When the vehicle accelerates, fluid in the high-pressure

Hybrid reactors: Nuclear breeding or energy production?

International Nuclear Information System (INIS)

Piera, Mireia; Lafuente, Antonio; Abanades, Alberto; Martinez-Val, J.M.

2010-01-01

After reviewing the long-standing tradition on hybrid research, an assessment model is presented in order to characterize the hybrid performance under different objectives. In hybrids, neutron multiplication in the subcritical blanket plays a major role, not only for energy production and nuclear breeding, but also for tritium breeding, which is fundamental requirement in fusion-fission hybrids. All three objectives are better achieved with high values of the neutron multiplication factor (k-eff) with the obvious and fundamental limitation that it cannot reach criticality under any event, particularly, in the case of a loss of coolant accident. This limitation will be very important in the selection of the coolant. Some general considerations will be proposed, as guidelines for assessing the hybrid potential in a given scenario. Those guidelines point out that hybrids can be of great interest for the future of nuclear energy in a framework of Sustainable Development, because they can contribute to the efficient exploitation of nuclear fuels, with very high safety features. Additionally, a proposal is presented on a blanket specially suited for fusion-fission hybrids, although this reactor concept is still under review, and new work is needed for identifying the most suitable blanket composition, which can vary depending on the main objective of the hybrid.

Hybrid spacecraft attitude control system

Directory of Open Access Journals (Sweden)

Renuganth Varatharajoo

2016-02-01

Full Text Available The hybrid subsystem design could be an attractive approach for futurespacecraft to cope with their demands. The idea of combining theconventional Attitude Control System and the Electrical Power System ispresented in this article. The Combined Energy and Attitude ControlSystem (CEACS consisting of a double counter rotating flywheel assemblyis investigated for small satellites in this article. Another hybrid systemincorporating the conventional Attitude Control System into the ThermalControl System forming the Combined Attitude and Thermal ControlSystem (CATCS consisting of a "fluid wheel" and permanent magnets isalso investigated for small satellites herein. The governing equationsdescribing both these novel hybrid subsystems are presented and theironboard architectures are numerically tested. Both the investigated novelhybrid spacecraft subsystems comply with the reference missionrequirements.The hybrid subsystem design could be an attractive approach for futurespacecraft to cope with their demands. The idea of combining theconventional Attitude Control System and the Electrical Power System ispresented in this article. The Combined Energy and Attitude ControlSystem (CEACS consisting of a double counter rotating flywheel assemblyis investigated for small satellites in this article. Another hybrid systemincorporating the conventional Attitude Control System into the ThermalControl System forming the Combined Attitude and Thermal ControlSystem (CATCS consisting of a "fluid wheel" and permanent magnets isalso investigated for small satellites herein. The governing equationsdescribing both these novel hybrid subsystems are presented and theironboard architectures are numerically tested. Both the investigated novelhybrid spacecraft subsystems comply with the reference missionrequirements.

Hybrid system concepts

International Nuclear Information System (INIS)

Landeyro, P.A.

1995-01-01

Hybrid systems studied for fissile material production, were reconsidered for minor actinide and long-lived fission product destruction as alternative to the traditional final disposal of nuclear waste. Now there are attempts to extend the use of the concepts developed for minor actinide incineration to plutonium burning. The most promising hybrid system concept considers fuel and target both as liquids. From the results obtained, the possibility to adopt composite targets seems the most promising solution, but still there remains the problem of Pu production, not acceptable in a burning system. This kind of targets can be mainly used for fissile material production, while for accelerator driven burners it is most convenient to use a liquid lead target. The most suitable solvent is heavy water for minor actinide annihilation in the blanket of a hybrid system. Due to the criticality conditions and the necessity of electric energy production, the blanket using plutonium dissolved in molten salts is the most convenient one. (author)

Asymmetric Hybrid Nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Chumanov, George [Clemson Univ., SC (United States)

2015-11-05

Hybrid Nanoparticles (AHNs) are rationally-designed multifunctional nanostructures and novel building blocks for the next generation of advanced materials and devices. Nanoscale materials attract considerable interest because of their unusual properties and potential for practical applications. Most of the activity in this field is focused on the synthesis of homogeneous nanoparticles from metals, metal oxides, semiconductors, and polymers. It is well recognized that properties of nanoparticles can be further enhanced if they are made as hybrid structures. This program is concerned with the synthesis, characterization, and application of such hybrid structures termed AHNs. AHNs are composed of a homogeneous core and several caps of different materials deposited on its surface (Fig. 1). Combined properties of the core and the caps as well as new properties that arise from core-cap and cap-cap interactions render AHNs multifunctional. In addition, specific chemical reactivity of the caps enables directional self-assembly of AHNs into complex architectures that are not possible with only spherical nanoparticles.

Hybrid pine for tough sites

International Nuclear Information System (INIS)

Davidson, W.H.

1994-01-01

A test planting of 30 first- and second-generation pitch x loblolly pine (pinus rigida x P. taeda) hybrids was established on a West Virginia minesoil in 1985. The site was considered orphaned because earlier attempts at revegetation were unsuccessful. The soil was acid (pH 4.6), lacking in nutrients, and compacted. Vegetation present at the time of planting consisted of a sparse cover of tall fescue (Festuca arundinacea) and poverty grass (Danthonia spicata) and a few sourwood (Oxydendrum arboreum) and mountain laurel (Kalmia latifolia) seedlings. In the planting trial, 30 different hybrids were set out in 4 tree linear plots replicated 5 times. The seedlings had been grown in containers for 1 yr before outplanting. Evaluations made after 6 growing seasons showed overall plantation survival was 93%; six hybrids and one open-pollinated cross survived 100%. Individual tree heights ranged from 50 to 425 cm with a plantation average of 235 cm (7.7 ft). Eleven of the hybrids had average heights that exceeded the plantation average. Another test planting of tree and shrub species on this site has very poor survival. Therefore, pitch x loblolly hybrid pine can be recommended for reclaiming this and similar sites

Case for the fusion hybrid

International Nuclear Information System (INIS)

Rose, R.P.

1981-01-01

The use of nuclear fusion to produce fuel for nuclear fission power stations is discussed in the context of a crucial need for future energy options. The fusion hybrid is first considered as an element in the future of nuclear fission power to provide long term assurance of adequate fuel supplies for both breeder and convertor reactors. Generic differences in neutronic characteristics lead to a fuel production potential of fusion-fission hybrid systems which is significantly greater than that obtainable with fission systems alone. Furthermore, cost benefit studies show a variety of scenarios in which the hybrid offers sufficient potential to justify development costs ranging in the tens of billions of dollars. The hybrid is then considered as an element in the ultimate development of fusion electric power. The hybrid offers a near term application of fusion where experience with the requisite technologies can be derived as a vital step in mapping a credible route to eventual commercial feasibility of pure fusion systems. Finally, the criteria for assessment of future energy options are discussed with prime emphasis on the need for rational comparision of alternatives

Hybrid perovskites: Approaches towards light-emitting devices

KAUST Repository

Alias, Mohd Sharizal

2016-10-06

The high optical gain and absorption of organic-inorganic hybrid perovskites have attracted extensive research for photonic device applications. Using the bromide halide as an example, we present key approaches of our work towards realizing efficient perovskites based light-emitters. The approaches involved determination of optical constants for the hybrid perovskites thin films, fabrication of photonic nanostructures in the form of subwavelength grating reflector patterned directly on the hybrid perovskites as light manipulation layer, and enhancing the emission property of the hybrid perovskites by using microcavity structure. Our results provide a platform for realization of hybrid perovskites based light-emitting devices for solid-state lighting and display applications. © 2016 IEEE.

Hybrid perovskites: Approaches towards light-emitting devices

KAUST Repository

Alias, Mohd Sharizal; Dursun, Ibrahim; Priante, Davide; Saidaminov, Makhsud I.; Ng, Tien Khee; Bakr, Osman; Ooi, Boon S.

2016-01-01

The high optical gain and absorption of organic-inorganic hybrid perovskites have attracted extensive research for photonic device applications. Using the bromide halide as an example, we present key approaches of our work towards realizing efficient perovskites based light-emitters. The approaches involved determination of optical constants for the hybrid perovskites thin films, fabrication of photonic nanostructures in the form of subwavelength grating reflector patterned directly on the hybrid perovskites as light manipulation layer, and enhancing the emission property of the hybrid perovskites by using microcavity structure. Our results provide a platform for realization of hybrid perovskites based light-emitting devices for solid-state lighting and display applications. © 2016 IEEE.

Hybrid colloidal plasmonic-photonic crystals.

Science.gov (United States)

Romanov, Sergei G; Korovin, Alexander V; Regensburger, Alois; Peschel, Ulf

2011-06-17

We review the recently emerged class of hybrid metal-dielectric colloidal photonic crystals. The hybrid approach is understood as the combination of a dielectric photonic crystal with a continuous metal film. It allows to achieve a strong modification of the optical properties of photonic crystals by involving the light scattering at electronic excitations in the metal component into moulding of the light flow in series to the diffraction resonances occurring in the body of the photonic crystal. We consider different realizations of hybrid plasmonic-photonic crystals based on two- and three-dimensional colloidal photonic crystals in association with flat and corrugated metal films. In agreement with model calculations, different resonance phenomena determine the optical response of hybrid crystals leading to a broadly tuneable functionality of these crystals. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Optimizing hybrid spreading in metapopulations.

Science.gov (United States)

Zhang, Changwang; Zhou, Shi; Miller, Joel C; Cox, Ingemar J; Chain, Benjamin M

2015-04-29

Epidemic spreading phenomena are ubiquitous in nature and society. Examples include the spreading of diseases, information, and computer viruses. Epidemics can spread by local spreading, where infected nodes can only infect a limited set of direct target nodes and global spreading, where an infected node can infect every other node. In reality, many epidemics spread using a hybrid mixture of both types of spreading. In this study we develop a theoretical framework for studying hybrid epidemics, and examine the optimum balance between spreading mechanisms in terms of achieving the maximum outbreak size. We show the existence of critically hybrid epidemics where neither spreading mechanism alone can cause a noticeable spread but a combination of the two spreading mechanisms would produce an enormous outbreak. Our results provide new strategies for maximising beneficial epidemics and estimating the worst outcome of damaging hybrid epidemics.

Mitochondrial Recombination and Introgression during Speciation by Hybridization.

Science.gov (United States)

Leducq, Jean-Baptiste; Henault, Mathieu; Charron, Guillaume; Nielly-Thibault, Lou; Terrat, Yves; Fiumera, Heather L; Shapiro, B Jesse; Landry, Christian R

2017-08-01

Genome recombination is a major source of genotypic diversity and contributes to adaptation and speciation following interspecies hybridization. The contribution of recombination in these processes has been thought to be largely limited to the nuclear genome because organelles are mostly uniparentally inherited in animals and plants, which prevents recombination. Unicellular eukaryotes such as budding yeasts do, however, transmit mitochondria biparentally, suggesting that during hybridization, both parents could provide alleles that contribute to mitochondrial functions such as respiration and metabolism in hybrid populations or hybrid species. We examined the dynamics of mitochondrial genome transmission and evolution during speciation by hybridization in the natural budding yeast Saccharomyces paradoxus. Using population-scale mitochondrial genome sequencing in two endemic North American incipient species SpB and SpC and their hybrid species SpC*, we found that both parental species contributed to the hybrid mitochondrial genome through recombination. We support our findings by showing that mitochondrial recombination between parental types is frequent in experimental crosses that recreate the early step of this speciation event. In these artificial hybrids, we observed that mitochondrial genome recombination enhances phenotypic variation among diploid hybrids, suggesting that it could play a role in the phenotypic differentiation of hybrid species. Like the nuclear genome, the mitochondrial genome can, therefore, also play a role in hybrid speciation. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Hybrid computing - Generalities and bibliography

International Nuclear Information System (INIS)

Neel, Daniele

1970-01-01

This note presents the content of a research thesis. It describes the evolution of hybrid computing systems, discusses the benefits and shortcomings of analogue or hybrid systems, discusses the building up of an hybrid system (requires properties), comments different possible uses, addresses the issues of language and programming, discusses analysis methods and scopes of application. An appendix proposes a bibliography on these issues and notably the different scopes of application (simulation, fluid dynamics, biology, chemistry, electronics, energy, errors, space, programming languages, hardware, mechanics, and optimisation of equations or processes, physics) [fr

Evolution of hybrid defect networks

International Nuclear Information System (INIS)

Martins, C. J. A. P.

2009-01-01

We apply a recently developed analytic model for the evolution of monopole networks to the case of monopoles attached to one string, usually known as hybrid networks. We discuss scaling solutions for both local and global hybrid networks, and also find an interesting application for the case of vortons. Our quantitative results agree with previous estimates in indicating that the hybrid networks will usually annihilate soon after the string-forming phase transition. However, we also show that in some specific circumstances these networks can survive considerably more than a Hubble time.

Evolution and molecular control of hybrid incompatibility in plants

Directory of Open Access Journals (Sweden)

Chen Chen

2016-08-01

Full Text Available Postzygotic reproductive isolation (RI plays an important role in speciation. According to the stage at which it functions and the symptoms it displays, postzygotic RI can be called hybrid inviability, hybrid weakness or necrosis, hybrid sterility, or hybrid breakdown. In this review, we summarized new findings about hybrid incompatibilities in plants, most of which are from studies on Arabidopsis and rice. Recent progress suggests that hybrid incompatibility is a by-product of co-evolution either with parasitic selfish elements in the genome or with invasive microbes in the natural environment. We discuss the environmental influences on the expression of hybrid incompatibility and the possible effects of environment-dependent hybrid incompatibility on sympatric speciation. We also discuss the role of domestication on the evolution of hybrid incompatibilities.

Car makers: the hybrid car stirs up competition; Constructeurs automobiles: la voiture hybride attise la concurrence

Energy Technology Data Exchange (ETDEWEB)

Bocquet, P.Y.; Dumas, A.

2006-03-15

The success of clean vehicles has favored the hybrid technology. Toyota has drawn away from its competitors which today have to make up their leeway. Hybridization has the advantage to be able to be adapted to any energy source type. It has been adapted to gasoline engines first, but it is gaining diesel engines and trucks too. However, the over-cost of this technology remains today the main drawback of hybrid vehicles. (J.S.)

Conceptual innovations in hybrid reactors

International Nuclear Information System (INIS)

Greenspan, E.; Miley, G.H.

1980-01-01

A number of innovations in the conception of fusion-fission hybrid reactors, including the blanket, the fusion driver, the coupling of the fusion and the fission components as well as the application of hybrid reactors are described, and their feasibility assessed

Comparison performance of split plug-in hybrid electric vehicle and hybrid electric vehicle using ADVISOR

Directory of Open Access Journals (Sweden)

Mohd Rashid Muhammad Ikram

2017-01-01

Full Text Available Electric vehicle suffers from relatively short range and long charging times and consequently has not become an acceptable solution to the automotive consumer. The addition of an internal combustion engine to extend the range of the electric vehicle is one method of exploiting the high efficiency and lack of emissions of the electric vehicle while retaining the range and convenient refuelling times of a conventional gasoline powered vehicle. The term that describes this type of vehicle is a hybrid electric vehicle. Many configurations of hybrid electric vehicles have been designed and implemented, namely the series, parallel and power-split configurations. This paper discusses the comparison between Split Plug-in Hybrid Electric Vehicle(SPHEV and Hybrid Electric Vehicle(HEV. Modelling methods such as physics-based Resistive Companion Form technique and Bond Graph method are presented with powertrain component and system modelling examples. The modelling and simulation capability of existing tools such as ADvanced VehIcle SimulatOR (ADVISOR is demonstrated through application examples. Since power electronics is indispensable in hybrid vehicles, the issue of numerical oscillations in dynamic simulations involving power electronics is briefly addressed.

Electrokinetic acceleration of DNA hybridization in microsystems.

Science.gov (United States)

Lei, Kin Fong; Wang, Yun-Hsiang; Chen, Huai-Yi; Sun, Jia-Hong; Cheng, Ji-Yen

2015-06-01

In this work, electrokinetic acceleration of DNA hybridization was investigated by different combinations of frequencies and amplitudes of actuating electric signals. Because the frequencies from low to high can induce different kinds of electrokinetic forces, i.e., electroosmotic to electrothermal forces, this work provides an in-depth investigation of electrokinetic enhanced hybridization. Concentric circular Cr/Au microelectrodes of 350 µm in diameter were fabricated on a glass substrate and probe DNA was immobilized on the electrode surface. Target DNA labeled with fluorescent dyes suspending in solution was then applied to the electrode. Different electrokinetic forces were induced by the application of different electric signals to the circular microelectrodes. Local microfluidic vortexes were generated to increase the collision efficiency between the target DNA suspending in solution and probe DNA immobilized on the electrode surface. DNA hybridization on the electrode surface could be accelerated by the electrokinetic forces. The level of hybridization was represented by the fluorescent signal intensity ratio. Results revealed that such 5-min dynamic hybridization increased 4.5 fold of signal intensity ratio as compared to a 1-h static hybridization. Moreover, dynamic hybridization was found to have better differentiation ability between specific and non-specific target DNA. This study provides a strategy to accelerate DNA hybridization in microsystems. Copyright © 2015 Elsevier B.V. All rights reserved.

Comparison between AOT40 and ozone uptake in forest trees of different species, age and site conditions

Science.gov (United States)

Matyssek, R.; Wieser, G.; Nunn, A. J.; Kozovits, A. R.; Reiter, I. M.; Heerdt, C.; Winkler, J. B.; Baumgarten, M.; Häberle, K.-H.; Grams, T. E. E.; Werner, H.; Fabian, P.; Havranek, W. M.

The current AOT40 concept for inferring risks in forest trees by ozone (O 3) injury is based on an accumulated external O 3 exposure rather than an internal O 3 dose or uptake rate. AOT40 assumes O 3 concentrations below 40 nl l -1 and night-time exposure to be negligible. Hence, this concept is rather inconsistent with observed forest conditions. In contrast, the flux concept of cumulative O 3 uptake (CU) into the leaves has the potential of reflecting a physiologically meaningful internal O 3 dose experienced by trees. In this paper, we relate AOT40 to cumulative O 3 uptake into European beech ( Fagus sylvatica), Norway spruce ( Picea abies), European larch ( Larix decidua) and cembran pine ( Pinus cembra) trees differing in size, age and site conditions. We demonstrate that the flux concept can be extended to the tree and the stand level, making use of sap flow measurements through tree trunks. Although in both seedlings and adult trees AOT40 may show some linearity in correlations with average CU, the latter varies, at given AOT40, by 25±11% within and between species. This is because O 3 flux is primarily influenced by stomatal aperture, the latter being affected by climate, canopy position, leaf and tree age while varying between species. In particular, if weighed by detoxification capacity, we suggest, therefore, O 3 uptake related air quality indices to be promoted towards ecologically meaningful standards in forest protection, overcoming the shortcomings of exposure concepts. As O 3 injury results from the balance between O 3 uptake and detoxification in the leaf mesophyll, we conclude the flux concept in combination with measures of biochemical defence to have the capacity for predicting tree response to O 3 stress.

Cellulose Dynamics during Foliar Litter Decomposition in an Alpine Forest Meta-Ecosystem

Directory of Open Access Journals (Sweden)

Kai Yue

2016-08-01

Full Text Available To investigate the dynamics and relative drivers of cellulose degradation during litter decomposition, a field experiment was conducted in three individual ecosystems (i.e., forest floor, stream, and riparian zone of an alpine forest meta-ecosystem on the eastern Tibetan Plateau. Four litter species (i.e., willow: Salix paraplesia, azalea: Rhododendron lapponicum, cypress: Sabina saltuaria, and larch: Larix mastersiana that had varying initial litter chemical traits were placed separately in litterbags and then incubated on the soil surface of forest floor plots or in the water of the stream and riparian zone plots. Litterbags were retrieved five times each year during the two-year experiment, with nine replicates each time for each treatment. The results suggested that foliar litter lost 32.2%–89.2% of the initial dry mass depending on litter species and ecosystem type after two-year’s incubation. The cellulose lost 60.1%–96.8% of the initial mass with degradation rate in the order of stream > riparian zone > forest floor. Substantial cellulose degradation occurred at the very beginning (i.e., in the first pre-freezing period of litter decomposition. Litter initial concentrations of phosphorus (P and lignin were found to be the dominant chemical traits controlling cellulose degradation regardless of ecosystems type. The local-scale environmental factors such as temperature, pH, and nutrient availability were important moderators of cellulose degradation rate. Although the effects of common litter chemical traits (e.g., P and lignin concentrations on cellulose degradation across different individual ecosystems were identified, local-scale environmental factors such as temperature and nutrient availability were found to be of great importance for cellulose degradation. These results indicated that local-scale environmental factors should be considered apart from litter quality for generating a reliable predictive framework for the drivers

Hybrid Fuel Cell Technology Overview

Energy Technology Data Exchange (ETDEWEB)

None available

2001-05-31

For the purpose of this STI product and unless otherwise stated, hybrid fuel cell systems are power generation systems in which a high temperature fuel cell is combined with another power generating technology. The resulting system exhibits a synergism in which the combination performs with an efficiency far greater than can be provided by either system alone. Hybrid fuel cell designs under development include fuel cell with gas turbine, fuel cell with reciprocating (piston) engine, and designs that combine different fuel cell technologies. Hybrid systems have been extensively analyzed and studied over the past five years by the Department of Energy (DOE), industry, and others. These efforts have revealed that this combination is capable of providing remarkably high efficiencies. This attribute, combined with an inherent low level of pollutant emission, suggests that hybrid systems are likely to serve as the next generation of advanced power generation systems.

Testing the 'hybrid susceptibility' and 'phenological sink' hypotheses using the P. balsamifera - P. deltoides hybrid zone and septoria leaf spot [Septoria musiva].

Science.gov (United States)

LeBoldus, Jared M; Isabel, Nathalie; Floate, Kevin D; Blenis, Peter; Thomas, Barb R

2013-01-01

Hybrid genotypes that arise between plant species frequently have increased susceptibility to arthropod pests and fungal pathogens. This pattern has been attributed to the breakdown of plant defenses ('Hybrid susceptibility' hypothesis) and (or) to extended periods of susceptibility attributed to plant phenologies in zones of species overlap and (or) hybridization ('phenological sink' hypothesis). We examined these hypotheses by assessing the susceptibility of parental and hybrid Populus host genotypes to a leaf spot disease caused by the fungal pathogen Septoria musiva. For this purpose, 214 genotypes were obtained from morphologically pure zones of P. balsamifera and P. deltoides, and from an intervening zone of overlap and hybridization on the drainage of the Red Deer River, Alberta, Canada. Genotypes were identified as P. balsamifera, P. deltoides, or hybrid using a suite of 27 species-specific SNP markers. Initially the genetic structure of the hybrid zone was characterized with 27.7% of trees classified as admixed individuals. To test the hybrid susceptibility hypothesis, a subset of 52 genotypes was inoculated with four isolates of S. musiva. Levels of susceptibility were P. balsamifera > F1 hybrid > P. deltoides. A further 53 genotypes were grown in a common garden to assess the effect of genotype on variation in leaf phenology. Leaf phenology was more variable within the category of hybrid genotypes than within categories of either parental species. Leaf phenology was also more variable for the category of trees originating in the hybrid (P. balsamifera - P. deltoides [hybrid and parental genotypes combined]) zone than in adjacent pure zones of the parental species. The results from the inoculation experiment support the hybrid intermediacy hypothesis. The results from the common garden experiment support the 'phenological sink' hypothesis. These findings have greatly increased our understanding of the epidemiology and ecology of fungal pathogens in plant

Testing the 'hybrid susceptibility' and 'phenological sink' hypotheses using the P. balsamifera - P. deltoides hybrid zone and septoria leaf spot [Septoria musiva].

Directory of Open Access Journals (Sweden)

Jared M LeBoldus

Full Text Available Hybrid genotypes that arise between plant species frequently have increased susceptibility to arthropod pests and fungal pathogens. This pattern has been attributed to the breakdown of plant defenses ('Hybrid susceptibility' hypothesis and (or to extended periods of susceptibility attributed to plant phenologies in zones of species overlap and (or hybridization ('phenological sink' hypothesis. We examined these hypotheses by assessing the susceptibility of parental and hybrid Populus host genotypes to a leaf spot disease caused by the fungal pathogen Septoria musiva. For this purpose, 214 genotypes were obtained from morphologically pure zones of P. balsamifera and P. deltoides, and from an intervening zone of overlap and hybridization on the drainage of the Red Deer River, Alberta, Canada. Genotypes were identified as P. balsamifera, P. deltoides, or hybrid using a suite of 27 species-specific SNP markers. Initially the genetic structure of the hybrid zone was characterized with 27.7% of trees classified as admixed individuals. To test the hybrid susceptibility hypothesis, a subset of 52 genotypes was inoculated with four isolates of S. musiva. Levels of susceptibility were P. balsamifera > F1 hybrid > P. deltoides. A further 53 genotypes were grown in a common garden to assess the effect of genotype on variation in leaf phenology. Leaf phenology was more variable within the category of hybrid genotypes than within categories of either parental species. Leaf phenology was also more variable for the category of trees originating in the hybrid (P. balsamifera - P. deltoides [hybrid and parental genotypes combined] zone than in adjacent pure zones of the parental species. The results from the inoculation experiment support the hybrid intermediacy hypothesis. The results from the common garden experiment support the 'phenological sink' hypothesis. These findings have greatly increased our understanding of the epidemiology and ecology of fungal

Stochastic Reachability Analysis of Hybrid Systems

CERN Document Server

Bujorianu, Luminita Manuela

2012-01-01

Stochastic reachability analysis (SRA) is a method of analyzing the behavior of control systems which mix discrete and continuous dynamics. For probabilistic discrete systems it has been shown to be a practical verification method but for stochastic hybrid systems it can be rather more. As a verification technique SRA can assess the safety and performance of, for example, autonomous systems, robot and aircraft path planning and multi-agent coordination but it can also be used for the adaptive control of such systems. Stochastic Reachability Analysis of Hybrid Systems is a self-contained and accessible introduction to this novel topic in the analysis and development of stochastic hybrid systems. Beginning with the relevant aspects of Markov models and introducing stochastic hybrid systems, the book then moves on to coverage of reachability analysis for stochastic hybrid systems. Following this build up, the core of the text first formally defines the concept of reachability in the stochastic framework and then...

Exotic hybrid mesons in hard electroproduction

CERN Document Server

Anikin, I V; Szymanowski, L; Teryaev, O V; Wallon, S

2005-01-01

We estimate the sizeable cross section for deep exclusive electroproduction of an exotic $J^{PC}=1^{-+}$ hybrid meson in the Bjorken regime. The production amplitude scales like the one for usual meson electroproduction, i.e. as $1/Q^2$. This is due to the non-vanishing leading twist distribution amplitude for the hybrid meson, which may be normalized thanks to its relation to the energy momentum tensor and to the QCD sum rules technique. The hard amplitude is considered up to next-to-leading order in $\\alpha_{S}$ and we explore the consequences of fixing the renormalization scale ambiguity through the BLM procedure. We study the particular case where the hybrid meson decays through a $\\pi\\eta $ meson pair. We discuss the $\\pi\\eta$ generalized distribution amplitude and then calculate the production amplitude for this process. We propose a forward-backward asymmetry in the production of $\\pi$ and $\\eta$ mesons as a signal for the hybrid meson production. We briefly comment on hybrid electroproduction at very ...

A hybrid mammalian cell cycle model

Directory of Open Access Journals (Sweden)

Vincent Noël

2013-08-01

Full Text Available Hybrid modeling provides an effective solution to cope with multiple time scales dynamics in systems biology. Among the applications of this method, one of the most important is the cell cycle regulation. The machinery of the cell cycle, leading to cell division and proliferation, combines slow growth, spatio-temporal re-organisation of the cell, and rapid changes of regulatory proteins concentrations induced by post-translational modifications. The advancement through the cell cycle comprises a well defined sequence of stages, separated by checkpoint transitions. The combination of continuous and discrete changes justifies hybrid modelling approaches to cell cycle dynamics. We present a piecewise-smooth version of a mammalian cell cycle model, obtained by hybridization from a smooth biochemical model. The approximate hybridization scheme, leading to simplified reaction rates and binary event location functions, is based on learning from a training set of trajectories of the smooth model. We discuss several learning strategies for the parameters of the hybrid model.

Nafion–clay hybrids with a network structure

KAUST Repository

Burgaz, Engin; Lian, Huiqin; Alonso, Rafael Herrera; Estevez, Luis; Kelarakis, Antonios; Giannelis, Emmanuel P.

2009-01-01

Nafion-clay hybrid membranes with a unique microstructure were synthesized using a fundamentally new approach. The new approach is based on depletion aggregation of suspended particles - a well-known phenomenon in colloids. For certain concentrations of clay and polymer, addition of Nafion solution to clay suspensions in water leads to a gel. Using Cryo-TEM we show that the clay particles in the hybrid gels form a network structure with an average cell size in the order of 500 nm. The hybrid gels are subsequently cast to produce hybrid Nafion-clay membranes. Compared to pure Nafion the swelling of the hybrid membranes in water and methanol is dramatically reduced while their selectivity (ratio of conductivity over permeability) increases. The small decrease of ionic conductivity for the hybrid membranes is more than compensated by the large decrease in methanol permeability. Lastly the hybrid membranes are much stiffer and can withstand higher temperatures compared to pure Nafion. Both of these characteristics are highly desirable for use in fuel cell applications, since a) they will allow the use of a thinner membrane circumventing problems associated with the membrane resistance and b) enable high temperature applications. © 2009 Elsevier Ltd. All rights reserved.

Sustainability assessment of a hybrid energy system

International Nuclear Information System (INIS)

Afgan, Nain H.; Carvalho, Maria G.

2008-01-01

A hybrid energy system in the form of the Object structure is the pattern for the structure of options in the evaluation of a hybrid system. The Object structure is defined as: Hybrid Energy System {[production (solar, wind, biomass, natural gas)] [utilization(electricity, heat, hydrogen)]}. In the evaluation of hybrid energy systems only several options are selected to demonstrate the sustainability assessment method application in the promotion of the specific quality of the hybrid energy system. In this analysis the following options are taken into a consideration: 1.Solar photo-voltaic power plant (PV PP), wind turbine power plant (WTPP) biomass thermal power plant (ThSTPP) for electricity, heat and hydrogen production. 2.Solar PV PP and wind power plant (WPP) for electricity and hydrogen production. 3.Biomass thermal steam turbine power plant (BThSTPP) and WPP for heat and hydrogen production. 4.Combined cycle gas turbine power plant for electricity and hydrogen production. 5.Cogeneration of electricity and water by the hybrid system. The sustainability assessment method is used for the evaluation of quality of the selected hybrid systems. In this evaluation the following indicators are used: economic indicator, environment indicator and social indicator

Nafion–clay hybrids with a network structure

KAUST Repository

Burgaz, Engin

2009-05-01

Nafion-clay hybrid membranes with a unique microstructure were synthesized using a fundamentally new approach. The new approach is based on depletion aggregation of suspended particles - a well-known phenomenon in colloids. For certain concentrations of clay and polymer, addition of Nafion solution to clay suspensions in water leads to a gel. Using Cryo-TEM we show that the clay particles in the hybrid gels form a network structure with an average cell size in the order of 500 nm. The hybrid gels are subsequently cast to produce hybrid Nafion-clay membranes. Compared to pure Nafion the swelling of the hybrid membranes in water and methanol is dramatically reduced while their selectivity (ratio of conductivity over permeability) increases. The small decrease of ionic conductivity for the hybrid membranes is more than compensated by the large decrease in methanol permeability. Lastly the hybrid membranes are much stiffer and can withstand higher temperatures compared to pure Nafion. Both of these characteristics are highly desirable for use in fuel cell applications, since a) they will allow the use of a thinner membrane circumventing problems associated with the membrane resistance and b) enable high temperature applications. © 2009 Elsevier Ltd. All rights reserved.

Deep electroproduction of exotic hybrid mesons

International Nuclear Information System (INIS)

Anikin, I.V.; Pire, B.; Szymanowski, L.; Teryaev, O.V.; Wallon, S.

2004-01-01

We evaluate the leading order amplitude for the deep exclusive electroproduction of an exotic hybrid meson in the Bjorken regime. We show that, contrarily to naive expectation, this amplitude factorizes at the twist 2 level and thus scales like usual meson electroproduction when the virtual photon and the hybrid meson are longitudinally polarized. Exotic hybrid mesons may thus be studied in electroproduction experiments at JLAB, HERA (HERMES) or CERN (Compass)

Hybrid magnets at Tohoku University

International Nuclear Information System (INIS)

Muto, Yoshio; Nakagawa, Yasuaki; Noto, Koshichi; Hoshi, Akira; Miura, Shigeto; Watanabe, Kazuo; Kido, Giyuu

1984-01-01

The High Field Laboratory for Superconducting Materials was established in April 1981 at Tohoku University in order to provide research facilities for the development of superconducting materials suitable for superconducting magnets for the plasma confinement in fusion reactors. Main facilities of this laboratory are three hybrid magnets up to 30 Tesla dc magnetic fields with inner bores from 32 to 52mm in diameter. The magnets consist of superconducting outer solenoids and water-cooled inner ones with a maximum steady power dissipation of 8 MW. The design and construction of these three hybrid magnets have finished in last three years, and two of them (HM-3;20T, 32 mm bore and HM-2; 23T, 52 mm bore) have already opened to scientists and engineers in the superconductivity and other fields. The rated field of the third hybrid magnet (HM-1) is 31 (or 29) Tesla in a bore of 32 (or 52) mm in diameter. By this hybrid system we have succeeded to produce 29.3 Tesla on April 21, 1984. Detailed descriptions are presented on the superconducting magnets, power supplies and cooling systems for them, water-cooled magnets, dc-high power source and water-cooled system for them, the monitoring and control system for the hybrid magnets including a super-minicomputer system, a hard-wired interlock system for the safety of human beings and machines, and so on. The fourth hybrid magnet system which aims at 35 Tesla as the next phase is also discussed. (author)

Electric and Hybrid Vehicle System Research and Development Project: Hybrid Vehicle Potential Assessment. Volume VI. Cost analysis

Energy Technology Data Exchange (ETDEWEB)

Hardy, K.S.

1979-09-30

The purpose of the cost analysis is to determine the economic feasibility of a variety of hybrid vehicles with respect to conventional vehicles specifically designed for the same duty cycle defined by the mission analysis. Several different hybrid configurations including parallel, parallel-flywheel, and series vehicles were evaluated. The ramifications of incorporating examples of advanced batteries, these being the advanced lead-acid, nickel-zinc, and sodium sulfur were also investigated. Vehicles were specifically designed with these batteries and for the driving cycles specified by the mission. Simulated operation on the missions yielded the energy consumption (petroleum and/or electricity) over the driving cycles. It was concluded that: in the event that gasoline prices reach $2.50 to $3.00/gal, hybrid vehicles in many applications will become economically competitive with conventional vehicles without subsidization; in some commercial applications hybrid vehicles could be economically competitive, when the gasoline price ranges from $1.20 to $1.50/gal. The cost per kWh per cycle of the advanced batteries is much more important economically than the specific energy; the series hybrid vehicles were found to be more expensive in comparison to the parallel or parallel-flywheel hybrids when designed as passenger vehicles; and hybrid vehicles designed for private use could become economically competitive and displace up to 50% of the fuel normally used on that mission if subsidies of $500 to $2000 were supplied to the owner/operator. (LCL)

Constructing decidable hybrid systems with velocity bounds

NARCIS (Netherlands)

Belta, C.; Habets, L.C.G.J.M.

2004-01-01

In this paper, the question of bi-similarity between hybrid systems and their discrete quotients is studied from a new point of view. We consider two classes of hybrid systems: piecewise affine hybrid systems on simplices and piecewise multi-affine systems on multi-dimensional rectangles. Given a

Agronomic and chemical characteristics of hybrid corn to ensiling

Directory of Open Access Journals (Sweden)

Flávia Borges de Assis

2014-12-01

Full Text Available Our aim was to evaluate agronomic and chemical characteristics of corn hybrids to ensiling. It were evaluated nine corn hybrids (MX 300, RB 9308, 2B655, XB 6012, GNZ 2500, PL6890, PRE 32D10, PRE 22T10 e AG 1051, with three replicates. The higher fresh matter yield were observed in the hybrids PL6890 and PRE 32D10, while the dry matter yield was observed in the hybrid PRE 32D10 (13.43 t ha-1. The hybrids PRE 32D10 and PRE 22T10 stood out to present higher percent of leaf in relation to whole plant, while the lower percent of stems was found in the hybrids MX 300, 2B655 and XB 6012, however the higher leaves: stems relation was found in XB 6012 (0.49. There was higher CP content in the hybrid PRE 32D10 (9.10% of DM, while the lower NDF (57.78% of DM and cellulose content (24.27% of DM were observed in the hybrid GNZ 2500. The hybrid PL6890 presented higher ADF and lignin contents, the others hybrids had values lower. The lower NDIN content was observed in the hybrid RB 9308, while the lower AIDN content occurred on the hybrid 2B655. The lower buffer capacity was observed in the hybrid 2B655 (0.29. There are some differences on chemical composition among the corn hybrids used in this study, however, it is recommended to use the hybrids MX 300, PL6890 and PRE 32D10 for showing higher dry matter yield, which may reflect in the amortization of silage production costs.

The hybrid electric vehicle revolution, off road

Energy Technology Data Exchange (ETDEWEB)

Wood, B.E. [ePower Technologies (United States)

2004-07-01

In this presentation the author presents concepts and details of hybrid vehicles in general, including their benefits, then describes off-road hybrid vehicles. Hybrid vehicles have been experimented with for over a century. Demonstrator vehicles include a diesel-electric tractor, an electric lawn tractor, a hybrid snow thrower, and a hybrid wheel loader. A duty cycle for the loader is shown with battery-assisted acceleration, and regenerative braking. Both of these keep the size of the engine small, the loads on it less variable, thus improving fuel economy. A hybrid excavator and its duty cycle is shown. A fuel cell lift truck that is currently in design is illustrated. The author then describes the possibilities of the hydrogen economy where sourcing and infrastructure are yet to be demonstrated on a commercial scale. The author predicts that off-road hydrogen fuel cell vehicles will be commercially viable five years before on-road applications. The author predicts hydrogen sourced from biogas, photovoltaics, and wind power. tabs, figs.

The governance of hybrid organisations

DEFF Research Database (Denmark)

Spear, Roger; Cornforth, Chris

2010-01-01

The focus of this chapter is on the governance of third sector organizations (TSOs) and the challenges that are raised by hybridity. In particular it will focus on the question how does hybridity affect governance structures and processes and the challenges that governing bodies face?...

Research of a hybrid undulator

International Nuclear Information System (INIS)

Ma Youwu; Wu Bing; Liu Bo

1995-12-01

A 1.5 m tapered hybrid undulator has been designed and built for mid-infrared free electron laser experiments at CIAE. The undulator utilizes the REC-steel hybrid configuration. The magnetic gap and magnetic field taper can be continuously adjusted. The rms error of the peak field is less than 0.53%. The electron trajectory deviation is around 0.03 mm. The design of undulator, sorting of magnets in hybrid undulator using simulated annealing technique, the motion of electron beam in the ideal and measured magnetic field, magnetic field measurement technique and magnetic field adjustment are described. (6 refs., 10 figs., 1 tab)

Hybrid keyword search auctions

KAUST Repository

Goel, Ashish

2009-01-01

Search auctions have become a dominant source of revenue generation on the Internet. Such auctions have typically used per-click bidding and pricing. We propose the use of hybrid auctions where an advertiser can make a per-impression as well as a per-click bid, and the auctioneer then chooses one of the two as the pricing mechanism. We assume that the advertiser and the auctioneer both have separate beliefs (called priors) on the click-probability of an advertisement. We first prove that the hybrid auction is truthful, assuming that the advertisers are risk-neutral. We then show that this auction is superior to the existing per-click auction in multiple ways: 1. We show that risk-seeking advertisers will choose only a per-impression bid whereas risk-averse advertisers will choose only a per-click bid, and argue that both kind of advertisers arise naturally. Hence, the ability to bid in a hybrid fashion is important to account for the risk characteristics of the advertisers. 2. For obscure keywords, the auctioneer is unlikely to have a very sharp prior on the click-probabilities. In such situations, we show that having the extra information from the advertisers in the form of a per-impression bid can result in significantly higher revenue. 3. An advertiser who believes that its click-probability is much higher than the auctioneer\\'s estimate can use per-impression bids to correct the auctioneer\\'s prior without incurring any extra cost. 4. The hybrid auction can allow the advertiser and auctioneer to implement complex dynamic programming strategies to deal with the uncertainty in the click-probability using the same basic auction. The per-click and per-impression bidding schemes can only be used to implement two extreme cases of these strategies. As Internet commerce matures, we need more sophisticated pricing models to exploit all the information held by each of the participants. We believe that hybrid auctions could be an important step in this direction. The

Hybrid keyword search auctions

KAUST Repository

Goel, Ashish; Munagala, Kamesh

2009-01-01

Search auctions have become a dominant source of revenue generation on the Internet. Such auctions have typically used per-click bidding and pricing. We propose the use of hybrid auctions where an advertiser can make a per-impression as well as a per-click bid, and the auctioneer then chooses one of the two as the pricing mechanism. We assume that the advertiser and the auctioneer both have separate beliefs (called priors) on the click-probability of an advertisement. We first prove that the hybrid auction is truthful, assuming that the advertisers are risk-neutral. We then show that this auction is superior to the existing per-click auction in multiple ways: 1. We show that risk-seeking advertisers will choose only a per-impression bid whereas risk-averse advertisers will choose only a per-click bid, and argue that both kind of advertisers arise naturally. Hence, the ability to bid in a hybrid fashion is important to account for the risk characteristics of the advertisers. 2. For obscure keywords, the auctioneer is unlikely to have a very sharp prior on the click-probabilities. In such situations, we show that having the extra information from the advertisers in the form of a per-impression bid can result in significantly higher revenue. 3. An advertiser who believes that its click-probability is much higher than the auctioneer's estimate can use per-impression bids to correct the auctioneer's prior without incurring any extra cost. 4. The hybrid auction can allow the advertiser and auctioneer to implement complex dynamic programming strategies to deal with the uncertainty in the click-probability using the same basic auction. The per-click and per-impression bidding schemes can only be used to implement two extreme cases of these strategies. As Internet commerce matures, we need more sophisticated pricing models to exploit all the information held by each of the participants. We believe that hybrid auctions could be an important step in this direction. The hybrid

Exotic hybrid mesons in hard electroproduction

International Nuclear Information System (INIS)

Anikin, I.V.; Pire, B.; Szymanowski, L.; Teryaev, O.V.; Wallon, S.

2005-01-01

We estimate the sizeable cross section for deep exclusive electroproduction of an exotic J PC =1 -+ hybrid meson in the Bjorken regime. The production amplitude scales like the one for usual meson electroproduction, i.e., as 1/Q 2 . This is due to the nonvanishing leading twist distribution amplitude for the hybrid meson, which may be normalized thanks to its relation to the energy-momentum tensor and to the QCD sum rules technique. The hard amplitude is considered up to next-to-leading order in α S and we explore the consequences of fixing the renormalization scale ambiguity through the Brodsky-Lepage-Mackenzie (BLM) procedure. We study the particular case where the hybrid meson decays through a πη meson pair. We discuss the πη generalized distribution amplitude and then calculate the production amplitude for this process. We propose a forward-backward asymmetry in the production of π and η mesons as a signal for the hybrid meson production. We briefly comment on hybrid electroproduction at very high energy, in the diffractive limit where a QCD Odderon exchange mechanism should dominate. The conclusion of our study is that hard electroproduction is a promising way to study exotic hybrid mesons, in particular, at JLAB, HERA (HERMES), or CERN (Compass)

Hybrid strategies in nanolithography

Energy Technology Data Exchange (ETDEWEB)

Saavedra, Hector M; Mullen, Thomas J; Zhang Pengpeng; Dewey, Daniel C; Claridge, Shelley A; Weiss, Paul S [Department of Chemistry, The Pennsylvania State University, University Park, PA 16802 (United States)], E-mail: psw@cnsi.ucla.edu

2010-03-15

Hybrid nanoscale patterning strategies combine the registration and addressability of conventional lithographic techniques with the chemical and physical functionality enabled by intermolecular, electrostatic and/or biological interactions. This review aims to highlight and to provide a comprehensive description of recent developments in hybrid nanoscale patterning strategies that enhance existing lithographic techniques or can be used to fabricate functional chemical patterns that interact with their environment. These functional structures create new capabilities, such as the fabrication of physicochemical surfaces that can recognize and capture analytes from complex liquid or gaseous mixtures. The nanolithographic techniques we describe can be classified into three general areas: traditional lithography, soft lithography and scanning-probe lithography. The strengths and limitations of each hybrid patterning technique will be discussed, along with the current and potential applications of the resulting patterned, functional surfaces.

The Hybrid Automobile and the Atkinson Cycle

Science.gov (United States)

Feldman, Bernard J.

2008-01-01

The hybrid automobile is a strikingly new automobile technology with a number of new technological features that dramatically improve energy efficiency. This paper will briefly describe how hybrid automobiles work; what are these new technological features; why the Toyota Prius hybrid internal combustion engine operates on the Atkinson cycle…

Hybrid Logical Analyses of the Ambient Calculus

DEFF Research Database (Denmark)

Bolander, Thomas; Hansen, Rene Rydhof

2010-01-01

In this paper, hybrid logic is used to formulate three control flow analyses for Mobile Ambients, a process calculus designed for modelling mobility. We show that hybrid logic is very well-suited to express the semantic structure of the ambient calculus and how features of hybrid logic can...

Prospects for Hybrid Breeding in Bioenergy Grasses

DEFF Research Database (Denmark)

Aguirre, Andrea Arias; Studer, Bruno; Frei, Ursula

2012-01-01

, we address crucial topics to implement hybrid breeding, such as the availability and development of heterotic groups, as well as biological mechanisms for hybridization control such as self-incompatibility (SI) and male sterility (MS). Finally, we present potential hybrid breeding schemes based on SI...... of different hybrid breeding schemes to optimally exploit heterosis for biomass yield in perennial ryegrass (Lolium perenne L.) and switchgrass (Panicum virgatum), two perennial model grass species for bioenergy production. Starting with a careful evaluation of current population and synthetic breeding methods...

Towards a Pattern Language for Hybrid Education

DEFF Research Database (Denmark)

Köppe, Christian; Nørgård, Rikke Toft; Pedersen, Alex Young

2017-01-01

-digital, academic-nonacademic, online-offline, formal-informal, learning-teaching and individual-collective. In doing so, hybrid education invites uncertainty, open-endedness, risk-taking, experimentation, critical creativity, disruption, dialogue and democracy (back) into the heart of education. Accordingly, we......In this paper we offer an initial framework for a pattern language of hybrid education. With the term hybrid education, we imply the use of educational design patterns that actively strive to cut across, circumventing or upheave traditional dichotomies within education such as physical...... see, within hybrid education, the promise to push against and circumvent current trends of marketization, managerialism and standardization in higher education today. Here, a pattern language for hybrid education presents an alternative way of designing for future higher education in ways...

Hybrid nanostructures: synthesis, morphology and functional properties

International Nuclear Information System (INIS)

Povolotskaya, A V; Povolotskiy, A V; Manshina, A A

2015-01-01

Hybrid nanostructures representing combinations of different materials and possessing properties that are absent in separate components forming the hybrid are discussed. Particular attention is given to hybrid structures containing plasmonic and magnetic nanoparticles, methods of their synthesis and the relationship between the composition, structure and properties. The functional features of the hybrid nanomaterials of various morphology (with core–shell structures, with encapsulated metal nanoparticles and with metal nanoparticles on the surface) are considered. The unique properties of these hybrid materials are demonstrated, which are of interest for solving problems of catalysis and photocatalysis, detecting impurities in various media, in vivo visualization, bioanalysis, as well as for the design of optical labels and multifunctional diagnostic nanoplatforms. The bibliography includes 182 references

The Porsche Panamera S E-Hybrid drivetrain; Der Antriebsstrang des Porsche Panamera S E-Hybrid

Energy Technology Data Exchange (ETDEWEB)

Semmler, D.; Kerner, J.; Spiegel, L.; Bitsche, O.; Rauner, T.; Stache, I.; Marques, M. [Dr. Ing. h.c. F. Porsche AG, Weissach (Germany)

2013-08-01

With the new Panamera S E-Hybrid, Porsche presents the first standard plug-in hybrid concept for the luxury sector. The drivetrain represents a consistent further development of the full-hybrid vehicles already successful on the market. However, it has been updated to achieve the lowest possible fuel consumption and to meet future emission laws before they even take effect. It was possible to increase the performance and efficiency of the hybrid components, significantly improving both electric performance as well as the electric range. A large part of that is due to the new electric machine. In the same installation space, we have managed to more than double the power to 70 kW. A new intelligent operating strategy also allows us to meet the EU6 exhaust gas limits. In addition to the efficiency improvement measures, the lithium-ion battery with its 9.4 kWh capacity especially contributes to the car's enhanced range. Thanks to the higher energy density of the new cell technology, the battery only needs a little more installation space in comparison with the Panamera S Hybrid. In pure electric operation, the vehicle reaches a top speed of 135 km/h (limited) and has an electric range of 36 kilometres in the NEDC profile. Typical Porsche performance is provided by the system power of 416 hp (306 kW). In NEDC standard consumption, the E-Hybrid's 3.1 l/100 km and CO{sub 2} emissions of 71 g/km have stayed attractively economical. (orig.)

Parallel Hybrid Vehicle Optimal Storage System

Science.gov (United States)

Bloomfield, Aaron P.

2009-01-01

A paper reports the results of a Hybrid Diesel Vehicle Project focused on a parallel hybrid configuration suitable for diesel-powered, medium-sized, commercial vehicles commonly used for parcel delivery and shuttle buses, as the missions of these types of vehicles require frequent stops. During these stops, electric hybridization can effectively recover the vehicle's kinetic energy during the deceleration, store it onboard, and then use that energy to assist in the subsequent acceleration.

Porsche GT3 R Hybrid. Prototype and race lab; Porsche GT3 R Hybrid. Technologietraeger und rollendes Labor

Energy Technology Data Exchange (ETDEWEB)

Armbruster, Daniel [Porsche Motorsport, Weissach (Germany); Hennings, Stephan [Karlsruher Institut fuer Technologie (KIT), Karlsruhe (Germany). Inst. fuer Fahrzeugsystemtechnik

2011-05-15

Hybrid technology is one of the key technologies for coping with changing future requirements in the area of individual mobility. This technology is already being used in small, mid-size and upper class vehicles and is perceived by the public as environmentally friendly. To date, however, no hybrid drive concepts suitable for mass production have been available for sports cars, such as the Porsche 911. In order to answer questions about the optimum design of hybrid drive systems for high-performance vehicles and about the use of future technologies in motor racing, Porsche Motorsport therefore developed the GT3 R Hybrid. (orig.)

The effects of hybridization on divergent venom phenotypes: Characterization of venom from Crotalus scutulatus scutulatus × Crotalus oreganus helleri hybrids.

Science.gov (United States)

Smith, Cara Francesca; Mackessy, Stephen P

2016-09-15

Hybridization between divergent species can be analyzed to elucidate expression patterns of distinct parental characteristics, as well as to provide information about the extent of reproductive isolation between species. A known hybrid cross between two rattlesnakes with highly divergent venom phenotypes provided the opportunity to examine occurrence of parental venom characteristics in the F1 hybrids as well as ontogenetic shifts in the expression of these characters as the hybrids aged. Although venom phenotypes of adult rattlesnake venoms are known for many species, the effect of hybridization on phenotype inheritance is not well understood, and effects of hybridization on venom ontogeny have not yet been investigated. The current study investigates both phenomena resulting from the hybridization of a male snake with type I degradative venom, Crotalus oreganus helleri (Southern Pacific Rattlesnake), and a female snake with type II highly toxic venom, Crotalus scutulatus scutulatus (Mojave Rattlesnake). SDS-PAGE, enzymology, Western blot and reversed phase HPLC (RP-HPLC) were used to characterize the venom of the C. o. helleri male, the C. s. scutulatus female and their two hybrid offspring as they aged. In general, Crotalus o. helleri × C. s. scutulatus hybrid venoms appeared to exhibit overlapping parental venom profiles, and several different enzyme activity patterns. Both hybrids expressed C. o. helleri father-specific myotoxins as well as C. s. scutulatus mother-specific Mojave toxin. Snake venom metalloprotease activity displayed apparent sex-influenced expression patterns, while hybrid serine protease activities were intermediate to parental activities. The C. s. scutulatus × C. o. helleri hybrid male's venom profile provided the strongest evidence that type I and type II venom characteristics are expressed simultaneously in hybrid venoms, as this snake contained distinctive characteristics of both parental species. However, the possibility of

Tough hybrid ceramic-based material with high strength

International Nuclear Information System (INIS)

Guo, Shuqi; Kagawa, Yutaka; Nishimura, Toshiyuki

2012-01-01

This study describes a tough and strong hybrid ceramic material consisting of platelet-like zirconium compounds and metal. A mixture of boron carbide and excess zirconium powder was heated to 1900 °C using a liquid-phase reaction sintering technique to produce a platelet-like ZrB 2 -based hybrid ceramic bonded by a thin zirconium layer. The platelet-like ZrB 2 grains were randomly present in the as-sintered hybrid ceramic. Relative to non-hybrid ceramics, the fracture toughness and flexural strength of the hybrid ceramic increased by approximately 2-fold.

Hybrid Doctoral Program: Innovative Practices and Partnerships

Science.gov (United States)

Alvich, Dori; Manning, JoAnn; McCormick, Kathy; Campbell, Robert

2012-01-01

This paper reflects on how one mid-Atlantic University innovatively incorporated technology into the development of a hybrid doctoral program in educational leadership. The paper describes a hybrid doctoral degree program using a rigorous design; challenges of reworking a traditional syllabus of record to a hybrid doctoral program; the perceptions…

Hybridization in East African swarm-raiding army ants

DEFF Research Database (Denmark)

Kronauer, Daniel Jc; Peters, Marcell K; Schöning, Caspar

2011-01-01

Hybridization can have complex effects on evolutionary dynamics in ants because of the combination of haplodiploid sex-determination and eusociality. While hybrid non-reproductive workers have been found in a range of species, examples of gene-flow via hybrid queens and males are rare. We studied...... hybridization in East African army ants (Dorylus subgenus Anomma) using morphology, mitochondrial DNA sequences, and nuclear microsatellites....

Shape Memory Composite Hybrid Hinge

Science.gov (United States)

Fang, Houfei; Im, Eastwood; Lin, John; Scarborough, Stephen

2012-01-01

There are two conventional types of hinges for in-space deployment applications. The first type is mechanically deploying hinges. A typical mechanically deploying hinge is usually composed of several tens of components. It is complicated, heavy, and bulky. More components imply higher deployment failure probability. Due to the existence of relatively moving components among a mechanically deploying hinge, it unavoidably has microdynamic problems. The second type of conventional hinge relies on strain energy for deployment. A tape-spring hinge is a typical strain energy hinge. A fundamental problem of a strain energy hinge is that its deployment dynamic is uncontrollable. Usually, its deployment is associated with a large impact, which is unacceptable for many space applications. Some damping technologies have been experimented with to reduce the impact, but they increased the risks of an unsuccessful deployment. Coalescing strain energy components with shape memory composite (SMC) components to form a hybrid hinge is the solution. SMCs are well suited for deployable structures. A SMC is created from a high-performance fiber and a shape memory polymer resin. When the resin is heated to above its glass transition temperature, the composite becomes flexible and can be folded or packed. Once cooled to below the glass transition temperature, the composite remains in the packed state. When the structure is ready to be deployed, the SMC component is reheated to above the glass transition temperature, and it returns to its as-fabricated shape. A hybrid hinge is composed of two strain energy flanges (also called tape-springs) and one SMC tube. Two folding lines are placed on the SMC tube to avoid excessive strain on the SMC during folding. Two adapters are used to connect the hybrid hinge to its adjacent structural components. While the SMC tube is heated to above its glass transition temperature, a hybrid hinge can be folded and stays at folded status after the temperature

Ion-exchange properties of zeolite/glass hybrid materials

International Nuclear Information System (INIS)

Taira, Nobuyuki; Yoshida, Kohei; Fukushima, Takuya

2017-01-01

Hybrid materials were prepared from ground glass powder and various zeolites such as A-type, mordenite, X-type, and Y-type zeolites, and their ion removal effect was investigated. The hybrid materials of A-type, Y-type, and mordenite zeolites showed similar Sr"2"+ removal rates from aqueous solutions. The removal rate of Sr"2"+ ions increased as the amount of zeolite in the hybrid materials increased. Compared with other hybrid materials, the hybrid materials of X-type zeolite showed higher Sr"2"+ removal rates, especially for zeolite content greater than 25%. As the amount of X-type zeolite in the hybrid materials increased, the Sr"2"+ removal rate increased greatly, with a 100% removal rate when the content of X-type zeolite exceeded 62.5%. (author)

Hybrid vertical cavity laser

DEFF Research Database (Denmark)

Chung, Il-Sug; Mørk, Jesper

2010-01-01

A new hybrid vertical cavity laser structure for silicon photonics is suggested and numerically investigated. It incorporates a silicon subwavelength grating as a mirror and a lateral output coupler to a silicon ridge waveguide.......A new hybrid vertical cavity laser structure for silicon photonics is suggested and numerically investigated. It incorporates a silicon subwavelength grating as a mirror and a lateral output coupler to a silicon ridge waveguide....

New hybrid systems: strategy and research programs

International Nuclear Information System (INIS)

Thomas, J.B.

2001-01-01

This short article gives a status of research and experimental programs concerning new hybrid systems. A hybrid system is made up of a subcritical core, a spallation target and of a particle accelerator that delivers a proton beam. The main asset of hybrid systems is to provide a large reactivity margin that would be very valuable to transmute actinide nuclei efficiently. As a consequence hybrid systems could be considered as actinide burner reactors integrated to a large population of classical nuclear reactors dedicated to electricity production. (A.C.)

Hybrid Reactor designs in the United States

International Nuclear Information System (INIS)

Wolkenhauer, W.C.

1978-01-01

This paper reviews the current, active, interrelated Hybrid Reactor development programs in the United States, and offers a probable future course of action for the technology. The Department of Energy (DOE) program primarily emphasizes development of Hybrid Reactors that are optimized for proliferation resistance. The Electric Power Research Institute (EPRI) program concentrates on avenues for Hybrid Reactor commercialization. The history of electrical generation technology has been one of steady movement toward higher power densities and higher quality fuels. An apparent advantage of the Hybrid Reactor option is that it follows this trend

Yield performance and stability of CMS-based triticale hybrids.

Science.gov (United States)

Mühleisen, Jonathan; Piepho, Hans-Peter; Maurer, Hans Peter; Reif, Jochen Christoph

2015-02-01

CMS-based triticale hybrids showed only marginal midparent heterosis for grain yield and lower dynamic yield stability compared to inbred lines. Hybrids of triticale (×Triticosecale Wittmack) are expected to possess outstanding yield performance and increased dynamic yield stability. The objectives of the present study were to (1) examine the optimum choice of the biometrical model to compare yield stability of hybrids versus lines, (2) investigate whether hybrids exhibit a more pronounced grain yield performance and yield stability, and (3) study optimal strategies to predict yield stability of hybrids. Thirteen female and seven male parental lines and their 91 factorial hybrids as well as 30 commercial lines were evaluated for grain yield in up to 20 environments. Hybrids were produced using a cytoplasmic male sterility (CMS)-inducing cytoplasm that originated from Triticumtimopheevii Zhuk. We found that the choice of the biometrical model can cause contrasting results and concluded that a group-by-environment interaction term should be added to the model when estimating stability variance of hybrids and lines. midparent heterosis for grain yield was on average 3 % with a range from -15.0 to 11.5 %. No hybrid outperformed the best inbred line. Hybrids had, on average, lower dynamic yield stability compared to the inbred lines. Grain yield performance of hybrids could be predicted based on midparent values and general combining ability (GCA)-predicted values. In contrast, stability variance of hybrids could be predicted only based on GCA-predicted values. We speculated that negative effects of the used CMS cytoplasm might be the reason for the low performance and yield stability of the hybrids. For this purpose a detailed study on the reasons for the drawback of the currently existing CMS system in triticale is urgently required comprising also the search of potentially alternative hybridization systems.

Novel brewing yeast hybrids: creation and application.

Science.gov (United States)

Krogerus, Kristoffer; Magalhães, Frederico; Vidgren, Virve; Gibson, Brian

2017-01-01

The natural interspecies Saccharomyces cerevisiae × Saccharomyces eubayanus hybrid yeast is responsible for global lager beer production and is one of the most important industrial microorganisms. Its success in the lager brewing environment is due to a combination of traits not commonly found in pure yeast species, principally low-temperature tolerance, and maltotriose utilization. Parental transgression is typical of hybrid organisms and has been exploited previously for, e.g., the production of wine yeast with beneficial properties. The parental strain S. eubayanus has only been discovered recently and newly created lager yeast strains have not yet been applied industrially. A number of reports attest to the feasibility of this approach and artificially created hybrids are likely to have a significant impact on the future of lager brewing. De novo S. cerevisiae × S. eubayanus hybrids outperform their parent strains in a number of respects, including, but not restricted to, fermentation rate, sugar utilization, stress tolerance, and aroma formation. Hybrid genome function and stability, as well as different techniques for generating hybrids and their relative merits are discussed. Hybridization not only offers the possibility of generating novel non-GM brewing yeast strains with unique properties, but is expected to aid in unraveling the complex evolutionary history of industrial lager yeast.

Applying hybridity: rhythms of the Hajj, Tumblr, and Snowden.

Directory of Open Access Journals (Sweden)

Paul O'Connor

2013-12-01

Full Text Available Hybridity has long been a contested term, critiqued as elitist and contradictory. This paper begins by arguing that hybridity has been debated too often and applied too seldom. It takes the premise that hybridity is an everyday fact of life and accordingly it should be articulated in academic works as a mode of analysis. In acknowledging works that call for the utilization of hybridity’s analytical potential this work applies hybridity to the analysis of three disparate topics, the modern pilgrimage to Mecca or hajj, the social networking and blogging platform Tumblr, and the Edward Snowden affair. Hybridity is contrasted with Lefebvre’s rhythmanalysis and applied as a conjoined conceptual focus on these issues. In each scenario a variety of hybrid connections are presented and situated in Bauman’s liquid modernity. These representations of hybridity highlight the manifold dimensions of the concept itself, that it can be superficial, political, celebrated, progressive, and mundane. Rather than dismiss the conceptual complexities of hybridity this paper calls for a harnessing of the broad scope of inference that hybridity presents in application. Working with hybridity thus provides a way to link topics and work organically between multiple disciplines.

Frontier battery development for hybrid vehicles

OpenAIRE

Lewis, Heather; Park, Haram; Paolini, Maion

2012-01-01

Abstract Background Interest in hybrid-electric vehicles (HEVs) has recently spiked, partly due to an increasingly negative view toward the U.S. foreign oil dependency and environmental concerns. Though HEVs are becoming more common, they have a significant price premium over gasoline-powered vehicles. One of the primary drivers of this “hybrid premium” is the cost of the vehicles’ batteries. This paper focuses on these batteries used in hybrid vehicles, examines the types of batteries used f...

Towards a Pattern Language for Hybrid Education

DEFF Research Database (Denmark)

Köppe, Christian; Nørgård, Rikke Toft; Pedersen, Alex Young

2018-01-01

In this paper we offer an initial framework for a pattern language of hybrid education. With the term hybrid education, we imply the use of educa- tional design patterns that actively strive to cut across, circumventing or upheave traditional dichotomies within education such as physical-digital......, academic-nonacademic, online-offline, formal-informal, learning-teaching and individual-collective. In doing so, hybrid education invites uncertainty, open-endedness, risk-taking, experimentation, critical creativity, disruption, dialogue and democracy (back) into the heart of education. Accordingly we see...... on teaching to the test, playing it safe, rankings or gaming the system approaches. Rather, hybrid education focuses on open-endedness, risk-taking, relational entanglements, experimentation, exploration and empathy. In this way, designing for hybrid education is in this paper achieved, partly by taking...

Impact of Vehicle Hybridization on Fuel Consumption Economy

OpenAIRE

Rezaei, Javad

2018-01-01

Air pollution, limited number of knownpetroleum resources and increasing of greenhouse gases have led the governmentsand researchers to have more investigation on Hybrid Electric Vehicles.Considering technical availability and manufacturing facilities with regardingto the final vehicle price, hybridization of conventional vehicles could be abetter choice than designing and manufacturing a new hybrid electric car.Parallel-Series hybrid electric vehicles(power-split) which is used in this study...

Anticorrosive organic/inorganic hybrid coatings

Science.gov (United States)

Gao, Tongzhai

Organic/inorganic hybrid coating system was developed for anticorrosion applications using polyurea, polyurethane or epoxide as the organic phase and polysiloxane, formed by sol-gel process, as the inorganic phase. Polyurea/polysiloxane hybrid coatings were formulated and moisture cured using HDI isocyanurate, alkoxysilane-functionalized HDI isocyanurate, and tetraethyl orthosilicate (TEOS) oligomers. Two urethanes were prepared using the same components as abovementioned in addition to the oligoesters derived from either cyclohexane diacids (CHDA) and 2-butyl-2-ethyl-1,3-propanediol (BEPD) or adipic acid (AA), isophthalic acid (IPA), 1,6-hexanediol (HD), and trimethylol propane (TMP). Accelerated weathering and outdoor exposure were performed to study the weatherability of the polyurethane/polysiloxane hybrid coating system. FTIR and solid-state 13C NMR revealed that the degradation of the hybrid coatings occurred at the urethane and ester functionalities of the organic phase. DMA and DSC analyses showed the glass transition temperature increased and broadened after weathering. SEM was employed to observe the change of morphology of the hybrid coatings and correlated with the gloss variation after weathering. Rutile TiO2 was formulated into polyurethane/polysiloxane hybrid coatings in order to investigate the effect of pigmentation on the coating properties and the sol-gel precursor. Chemical interaction between the TiO2 and the sol-gel precursor was investigated using solid-state 29Si NMR and XPS. The morphology, mechanical, viscoelastic, thermal properties of the pigmented coatings were evaluated as a function of pigmentation volume concentration (PVC). Using AFM and SEM, the pigment were observed to be well dispersed in the polymer matrix. The thermal stability, the tensile modulus and strength of the coatings were enhanced with increasing PVC, whereas the pull-off adhesion and flexibility were reduced with increasing PVC. Finally, the pigmented coatings were

Euro hybrid materials and structures. Proceedings

Energy Technology Data Exchange (ETDEWEB)

Hausmann, Joachim M.; Siebert, Marc (eds.)

2016-08-01

In order to use the materials as best as possible, several different materials are usually mixed in one component, especially in the field of lightweight design. If these combinations of materials are joined inherently, they are called multi material design products or hybrid structures. These place special requirements on joining technology, design methods and manufacturing and are challenging in other aspects, too. The eight chapters with manuscripts of the presentations are: Chapter 1- Interface: What happens in the interface between the two materials? Chapter 2 - Corrosion and Residual Stresses: How about galvanic corrosion and thermal residual stresses in the contact zone of different materials? Chapter 3 - Characterization: How to characterize and test hybrid materials? Chapter 4 - Design: What is a suitable design and dimensioning method for hybrid structures? Chapter 5 - Machining and Processing: How to machine and process hybrid structures and materials? Chapter 6 - Component Manufacturing: What is a suitable manufacturing route for hybrid structures? Chapter 7 - Non-Destructive Testing and Quality Assurance: How to assure the quality of material and structures? Chapter 8 - Joining: How to join components of different materials?.

Bio-inspired Hybrid Carbon Nanotube Muscles

Science.gov (United States)

Kim, Tae Hyeob; Kwon, Cheong Hoon; Lee, Changsun; An, Jieun; Phuong, Tam Thi Thanh; Park, Sun Hwa; Lima, Márcio D.; Baughman, Ray H.; Kang, Tong Mook; Kim, Seon Jeong

2016-05-01

There has been continuous progress in the development for biomedical engineering systems of hybrid muscle generated by combining skeletal muscle and artificial structure. The main factor affecting the actuation performance of hybrid muscle relies on the compatibility between living cells and their muscle scaffolds during cell culture. Here, we developed a hybrid muscle powered by C2C12 skeletal muscle cells based on the functionalized multi-walled carbon nanotubes (MWCNT) sheets coated with poly(3,4-ethylenedioxythiophene) (PEDOT) to achieve biomimetic actuation. This hydrophilic hybrid muscle is physically durable in solution and responds to electric field stimulation with flexible movement. Furthermore, the biomimetic actuation when controlled by electric field stimulation results in movement similar to that of the hornworm by patterned cell culture method. The contraction and relaxation behavior of the PEDOT/MWCNT-based hybrid muscle is similar to that of the single myotube movement, but has faster relaxation kinetics because of the shape-maintenance properties of the freestanding PEDOT/MWCNT sheets in solution. Our development provides the potential possibility for substantial innovation in the next generation of cell-based biohybrid microsystems.

Euro hybrid materials and structures. Proceedings

International Nuclear Information System (INIS)

Hausmann, Joachim M.; Siebert, Marc

2016-01-01

In order to use the materials as best as possible, several different materials are usually mixed in one component, especially in the field of lightweight design. If these combinations of materials are joined inherently, they are called multi material design products or hybrid structures. These place special requirements on joining technology, design methods and manufacturing and are challenging in other aspects, too. The eight chapters with manuscripts of the presentations are: Chapter 1- Interface: What happens in the interface between the two materials? Chapter 2 - Corrosion and Residual Stresses: How about galvanic corrosion and thermal residual stresses in the contact zone of different materials? Chapter 3 - Characterization: How to characterize and test hybrid materials? Chapter 4 - Design: What is a suitable design and dimensioning method for hybrid structures? Chapter 5 - Machining and Processing: How to machine and process hybrid structures and materials? Chapter 6 - Component Manufacturing: What is a suitable manufacturing route for hybrid structures? Chapter 7 - Non-Destructive Testing and Quality Assurance: How to assure the quality of material and structures? Chapter 8 - Joining: How to join components of different materials?

Speciation and reduced hybrid female fertility in house mice.

Science.gov (United States)

Suzuki, Taichi A; Nachman, Michael W

2015-09-01

In mammals, intrinsic postzygotic isolation has been well studied in males but has been less studied in females, despite the fact that female gametogenesis and pregnancy provide arenas for hybrid sterility or inviability that are absent in males. Here, we asked whether inviability or sterility is observed in female hybrids of Mus musculus domesticus and M. m. musculus, taxa which hybridize in nature and for which male sterility has been well characterized. We looked for parent-of-origin growth phenotypes by measuring adult body weights in F1 hybrids. We evaluated hybrid female fertility by crossing F1 females to a tester male and comparing multiple reproductive parameters between intrasubspecific controls and intersubspecific hybrids. Hybrid females showed no evidence of parent-of-origin overgrowth or undergrowth, providing no evidence for reduced viability. However, hybrid females had smaller litter sizes, reduced embryo survival, fewer ovulations, and fewer small follicles relative to controls. Significant variation in reproductive parameters was seen among different hybrid genotypes, suggesting that hybrid incompatibilities are polymorphic within subspecies. Differences in reproductive phenotypes in reciprocal genotypes were observed and are consistent with cyto-nuclear incompatibilities or incompatibilities involving genomic imprinting. These findings highlight the potential importance of reduced hybrid female fertility in the early stages of speciation. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

Field errors in hybrid insertion devices

International Nuclear Information System (INIS)

Schlueter, R.D.

1995-02-01

Hybrid magnet theory as applied to the error analyses used in the design of Advanced Light Source (ALS) insertion devices is reviewed. Sources of field errors in hybrid insertion devices are discussed

Field errors in hybrid insertion devices

Energy Technology Data Exchange (ETDEWEB)

Schlueter, R.D. [Lawrence Berkeley Lab., CA (United States)

1995-02-01

Hybrid magnet theory as applied to the error analyses used in the design of Advanced Light Source (ALS) insertion devices is reviewed. Sources of field errors in hybrid insertion devices are discussed.

Mechanisms of Surface-Mediated DNA Hybridization

Science.gov (United States)

2015-01-01

Single-molecule total internal reflection fluorescence microscopy was employed in conjunction with resonance energy transfer (RET) to observe the dynamic behavior of donor-labeled ssDNA at the interface between aqueous solution and a solid surface decorated with complementary acceptor-labeled ssDNA. At least 100 000 molecular trajectories were determined for both complementary strands and negative control ssDNA. RET was used to identify trajectory segments corresponding to the hybridized state. The vast majority of molecules from solution adsorbed nonspecifically to the surface, where a brief two-dimensional search was performed with a 7% chance of hybridization. Successful hybridization events occurred with a characteristic search time of ∼0.1 s, and unsuccessful searches resulted in desorption from the surface, ultimately repeating the adsorption and search process. Hybridization was reversible, and two distinct modes of melting (i.e., dehybridization) were observed, corresponding to long-lived (∼15 s) and short-lived (∼1.4 s) hybridized time intervals. A strand that melted back onto the surface could rehybridize after a brief search or desorb from the interface. These mechanistic observations provide guidance for technologies that involve DNA interactions in the near-surface region, suggesting a need to design surfaces that both enhance the complex multidimensional search process and stabilize the hybridized state. PMID:24708278

Pressure Drop Test of Hybrid Mixing Vane Spacer Grid

Energy Technology Data Exchange (ETDEWEB)

Oh, D. S.; Chang, S. K.; Kim, B. D.; Chun, S. Y.; Chun, T. H

2007-08-15

The pressure loss test has been accomplished in the test section containing 5x5 rod bundle with a length of 2 m including 3 spacer grids. The test has been performed for the 5 kinds of spacer grids to compare the pressure loss characteristics: 1. Plain spacer grid which has the same body of the Hybrid but without vane (Plain), 2. Hybrid Vane spacer grid (Hybrid), 3. Hybrid-SC spacer grid which is constructed with coined, chamfered strip and is fabricated by spot welding, 4. Hybrid-LC spacer grid which is constructed with coined, chamfered strip and is fabricated by line welding along intersection line, 5. Westinghouse spacer grid with split vane (Plus-7). The pressure loss coefficient of the Plain, Hybrid, Hybrid-SC, Hybrid-LC, and Plus-7 spacer grid is 0.93, 1.15, 1.02, 1.04, and 1.08, respectively.

Molecular data highlight hybridization in squirrel monkeys (Saimiri, Cebidae

Directory of Open Access Journals (Sweden)

Jeferson Carneiro

Full Text Available Abstract Hybridization has been reported increasingly frequently in recent years, fueling the debate on its role in the evolutionary history of species. Some studies have shown that hybridization is very common in captive New World primates, and hybrid offspring have phenotypes and physiological responses distinct from those of the "pure" parents, due to gene introgression. Here we used the TA15 Alu insertion to investigate hybridization in the genus Saimiri. Our results indicate the hybridization of Saimiri boliviensis peruviensis with S. sciureus macrodon, and S. b. boliviensis with S. ustus. Unexpectedly, some hybrids of both S. boliviensis peruviensis and S. b. boliviensis were homozygous for the absence of the insertion, which indicates that the hybrids were fertile.

Multifaceted, cross-generational costs of hybridization in sibling Drosophila species.

Directory of Open Access Journals (Sweden)

Erin M Myers

Full Text Available Maladaptive hybridization, as determined by the pattern and intensity of selection against hybrid individuals, is an important factor contributing to the evolution of prezygotic reproductive isolation. To identify the consequences of hybridization between Drosophila pseudoobscura and D. persimilis, we estimated multiple fitness components for F1 hybrids and backcross progeny and used these to compare the relative fitness of parental species and their hybrids across two generations. We document many sources of intrinsic (developmental and extrinsic (ecological selection that dramatically increase the fitness costs of hybridization beyond the well-documented F1 male sterility in this model system. Our results indicate that the cost of hybridization accrues over multiple generations and reinforcement in this system is driven by selection against hybridization above and beyond the cost of hybrid male sterility; we estimate a fitness loss of >95% relative to the parental species across two generations of hybridization. Our findings demonstrate the importance of estimating hybridization costs using multiple fitness measures from multiple generations in an ecologically relevant context; so doing can reveal intense postzygotic selection against hybridization and thus, an enhanced role for reinforcement in the evolution of populations and diversification of species.

Multifaceted, cross-generational costs of hybridization in sibling Drosophila species.

Science.gov (United States)

Myers, Erin M; Harwell, Tiffany I; Yale, Elizabeth L; Lamb, Abigail M; Frankino, W Anthony

2013-01-01

Maladaptive hybridization, as determined by the pattern and intensity of selection against hybrid individuals, is an important factor contributing to the evolution of prezygotic reproductive isolation. To identify the consequences of hybridization between Drosophila pseudoobscura and D. persimilis, we estimated multiple fitness components for F1 hybrids and backcross progeny and used these to compare the relative fitness of parental species and their hybrids across two generations. We document many sources of intrinsic (developmental) and extrinsic (ecological) selection that dramatically increase the fitness costs of hybridization beyond the well-documented F1 male sterility in this model system. Our results indicate that the cost of hybridization accrues over multiple generations and reinforcement in this system is driven by selection against hybridization above and beyond the cost of hybrid male sterility; we estimate a fitness loss of >95% relative to the parental species across two generations of hybridization. Our findings demonstrate the importance of estimating hybridization costs using multiple fitness measures from multiple generations in an ecologically relevant context; so doing can reveal intense postzygotic selection against hybridization and thus, an enhanced role for reinforcement in the evolution of populations and diversification of species.

Hybrid, plug-in hybrid, or electric—What do car buyers want?

International Nuclear Information System (INIS)

Axsen, Jonn; Kurani, Kenneth S.

2013-01-01

We use a survey to compare consumers’ stated interest in conventional gasoline (CV), hybrid (HEV), plug-in hybrid (PHEV) and pure electric vehicles (EV) of varying designs and prices. Data are from 508 households representing new vehicle buyers in San Diego County, California in 2011. The mixed-mode survey collected information about access to residential recharge infrastructure, three days of driving patterns, and desired vehicle designs and motivations via design games. Across the higher and lower price scenarios, a majority of consumers designed and selected some form of PHEV for their next new vehicle, smaller numbers designed an HEV or a conventional vehicle, and only a few percent designed an EV. Of those who did not design an EV, the most frequent concerns with EVs were limited range, charger availability, and higher vehicle purchase prices. Positive interest in HEVs, PHEVs and EVs was associated with vehicle images of intelligence, responsibility, and support of the environment and nation (United States). The distribution of vehicle designs suggests that cheaper, smaller battery PHEVs may achieve more short-term market success than larger battery PHEVs or EV. New car buyers’ present interests align with less expensive first steps in a transition to electric-drive vehicles. - Highlights: • We assess consumer interest in various electric-drive vehicle designs. • Web-based design games completed by 508 households from San Diego, California. • Plug-in hybrids are most popular, followed by hybrids and conventional vehicles. • Only a few percent opted for a pure electric vehicle. • Electric-drive associated with intelligence, responsibility, and environment

Hybrid Organic/Inorganic Nanocomposites for Photovoltaic Cells

Science.gov (United States)

Liu, Ruchuan

2014-01-01

Inorganic/organic hybrid solar cells have attracted a lot of interest due to their potential in combining the advantages of both components. To understand the key issues in association with photoinduced charge separation/transportation processes and to improve overall power conversion efficiency, various combinations with nanostructures of hybrid systems have been investigated. Here, we briefly review the structures of hybrid nanocomposites studied so far, and attempt to associate the power conversion efficiency with these nanostructures. Subsequently, we are then able to summarize the factors for optimizing the performance of inorganic/organic hybrid solar cells. PMID:28788591

What controls the hybridization thermodynamics of spherical nucleic acids?

Science.gov (United States)

Randeria, Pratik S; Jones, Matthew R; Kohlstedt, Kevin L; Banga, Resham J; Olvera de la Cruz, Monica; Schatz, George C; Mirkin, Chad A

2015-03-18

The hybridization of free oligonucleotides to densely packed, oriented arrays of DNA modifying the surfaces of spherical nucleic acid (SNA)-gold nanoparticle conjugates occurs with negative cooperativity; i.e., each binding event destabilizes subsequent binding events. DNA hybridization is thus an ever-changing function of the number of strands already hybridized to the particle. Thermodynamic quantification of this behavior reveals a 3 orders of magnitude decrease in the binding constant for the capture of a free oligonucleotide by an SNA conjugate as the fraction of pre-hybridized strands increases from 0 to ∼30%. Increasing the number of pre-hybridized strands imparts an increasing enthalpic penalty to hybridization that makes binding more difficult, while simultaneously decreasing the entropic penalty to hybridization, which makes binding more favorable. Hybridization of free DNA to an SNA is thus governed by both an electrostatic barrier as the SNA accumulates charge with additional binding events and an effect consistent with allostery, where hybridization at certain sites on an SNA modify the binding affinity at a distal site through conformational changes to the remaining single strands. Leveraging these insights allows for the design of conjugates that hybridize free strands with significantly higher efficiencies, some of which approach 100%.

Analysis of product efficiency of hybrid vehicles and promotion policies

International Nuclear Information System (INIS)

Choi, Hyundo; Oh, Inha

2010-01-01

The key aim of this study is to evaluate the product efficiency of current hybrid vehicles and suggest effective policies to promote hybrid vehicles in the Korean automobile market and development trends of hybrid vehicles. The efficiency levels for car models sold in Korea, including hybrid ones, were measured using the recently developed discrete additive data envelopment analysis (DEA) model that reflects consumer preference. The result of the analysis shows that current hybrid vehicles on the market are still at lower competitive advantage than traditional car models with conventional combustion engines and we can suggest a mix of incentive policies to promote the competitiveness of hybrid vehicles. In addition, we also identify two distinctive trends of hybrid vehicle development: environment-oriented hybrid vehicles and performance-oriented hybrid vehicles. It implies that the government should take account of development trends of hybrid vehicles to achieve the policy goals in designing support schemes and automobile companies that are willing to develop hybrid vehicles can also gain some insights for making strategic decisions. (author)

Automated DNA electrophoresis, hybridization and detection

International Nuclear Information System (INIS)

Zapolski, E.J.; Gersten, D.M.; Golab, T.J.; Ledley, R.S.

1986-01-01

A fully automated, computer controlled system for nucleic acid hybridization analysis has been devised and constructed. In practice, DNA is digested with restriction endonuclease enzyme(s) and loaded into the system by pipette; 32 P-labelled nucleic acid probe(s) is loaded into the nine hybridization chambers. Instructions for all the steps in the automated process are specified by answering questions that appear on the computer screen at the start of the experiment. Subsequent steps are performed automatically. The system performs horizontal electrophoresis in agarose gel, fixed the fragments to a solid phase matrix, denatures, neutralizes, prehybridizes, hybridizes, washes, dries and detects the radioactivity according to the specifications given by the operator. The results, printed out at the end, give the positions on the matrix to which radioactivity remains hybridized following stringent washing

Collective Identity Formation in Hybrid Organizations

DEFF Research Database (Denmark)

Boulongne, Romain; Boxenbaum, Eva

The present article examines the process of collective identity formation in the context of hybrid organizing. Empirically, we investigate hybrid organizing in a collaborative structure at the interface of two heterogeneous organizations in the domain of new renewable energies. We draw...... on the literature on knowledge sharing across organizational boundaries, particularly the notions of transfer, translation and transformation, to examine in real time how knowledge sharing in a hybrid setting contributes (or not) to the emergence of a new collective identity at the interface of two heterogeneous...... organizations. Our findings point to two factors that limit knowledge sharing and hence to new collective identity formation in a hybrid space: 1) ambiguous or multiple organizational roles and 2) strong identities of the collaborating organizations. These findings contribute to illuminating the initial...

Hybrid composites

CSIR Research Space (South Africa)

Jacob John, Maya

2009-04-01

Full Text Available mixed short sisal/glass hybrid fibre reinforced low density polyethylene composites was investigated by Kalaprasad et al [25].Chemical surface modifications such as alkali, acetic anhydride, stearic acid, permanganate, maleic anhydride, silane...

Shape Grammars for Innovative Hybrid Typological Design

DEFF Research Database (Denmark)

Al-kazzaz, Dhuha; Bridges, Alan; Chase, Scott Curland

2010-01-01

This paper describes a new methodology of deriving innovative hybrid designs using shape grammars of heterogeneous designs. The method is detailed within three phases of shape grammars: analysis, synthesis and evaluation. In the analysis phase, the research suggests that original rules of each...... design component are grouped in subclass rule sets to facilitate rule choices. Additionally, adding new hybrid rules to original rules expands the options available to the grammar user. In the synthesis phase, the research adopts state labels and markers to drive the design generation. The former...... is implemented with a user guide grammar to ensure hybridity in the generated design, while the latter aims to ensure feasible designs. Lastly evaluation criteria are added to measure the degree of innovation of the hybrid designs. This paper describes the derivation of hybrid minaret designs from a corpus...

Molecular evidence for natural hybridization in the mangrove genus avicennia

International Nuclear Information System (INIS)

Huang, L.; Huang Y; Shi, S.; Zhou, R

2014-01-01

Hybridization has been observed in several multi-species genera of mangroves; however, there has been no report on hybridization in Avicennia in the Indo-West Pacific region. In this study, we sequenced 5 low-copy nuclear genes of Avicennia marina, A. rumphiana and 2 individuals of their putative hybrid in the Southeast Asia region to test the hypothesis of natural hybridization between these 2 species. We demonstrated that both putative hybrid individuals possessed two types of sequences at each of the 5 genes, perfectly corresponding to those of A. marina and A. rumphiana, confirming the hybridization between these 2 Avicennia species, and the 2 hybrid individuals are most likely F1 hybrids. Sequencing of the chloroplast trnH-psbA regions indicated that A. marina was the maternal parent of the two hybrid individuals. (author)

Double-staining chromogenic in situ hybridization as a useful alternative to split-signal fluorescence in situ hybridization in lymphoma diagnostics

DEFF Research Database (Denmark)

van Rijk, A.; Svenstroup-Poulsen, T.; Jones, M.

2010-01-01

within the reach of every pathology laboratory. Design and Methods Our study was initiated to determine the consistency between chromogenic in situ hybridization and fluorescence in situ hybridization, both using split-signal probes developed for the detection of chromosomal breaks. Five hundred...... and actual signal were compared to the original fluorescence hybridization results. In addition, hematoxylin background staining intensity and signal intensity of the double-staining chromogenic in situ hybridization procedure were analyzed. Results With respect to the presence or absence of chromosomal...

Operation management of daily economic dispatch using novel hybrid particle swarm optimization and gravitational search algorithm with hybrid mutation strategy

Science.gov (United States)

Wang, Yan; Huang, Song; Ji, Zhicheng

2017-07-01

This paper presents a hybrid particle swarm optimization and gravitational search algorithm based on hybrid mutation strategy (HGSAPSO-M) to optimize economic dispatch (ED) including distributed generations (DGs) considering market-based energy pricing. A daily ED model was formulated and a hybrid mutation strategy was adopted in HGSAPSO-M. The hybrid mutation strategy includes two mutation operators, chaotic mutation, Gaussian mutation. The proposed algorithm was tested on IEEE-33 bus and results show that the approach is effective for this problem.

Discordant introgression in a rapidly expanding hybrid swarm

Science.gov (United States)

Ward, Jessica L.; Blum, Mike J.; Walters, David M.; Porter, Brady A.; Burkhead, Noel; Freeman, Byron

2012-01-01

The erosion of species boundaries can involve rapid evolutionary change. Consequently, many aspects of the process remain poorly understood, including the formation, expansion, and evolution of hybrid swarms. Biological invasions involving hybridization present exceptional opportunities to study the erosion of species boundaries because timelines of interactions and outcomes are frequently well known. Here, we examined clinal variation across codominant and maternally inherited genetic markers as well as phenotypic traits to characterize the expansion and evolution of a hybrid swarm between native Cyprinella venusta and invasive Cyprinella lutrensis minnows. Discordant introgression of phenotype, microsatellite multilocus genotype, and mtDNA haplotype indicates that the observable expansion of the C. venusta x C. lutrensis hybrid swarm is a false invasion front. Both parental and hybrid individuals closely resembling C. lutrensis are numerically dominant in the expansion wake, indicating that the non-native parental phenotype may be selectively favored. These findings show that cryptic introgression can extend beyond the phenotypic boundaries of hybrid swarms and that hybrid swarms likely expand more rapidly than can be documented from phenotypic variation alone. Similarly, dominance of a single parental phenotype following an introduction event may lead to instances of species erosion being mistaken for species displacement without hybridization.

Electrodeposition of hybrid ZnO/organic dye films

Energy Technology Data Exchange (ETDEWEB)

Moya, Monica; Mari, Bernabe; Mollar, Miquel [Department de Fisica Aplicada-IDF, Universitat Politecnica de Valencia, Cami de Vera s/n, 46022 Valencia (Spain)

2011-06-15

The viability of the electrodeposition as a suitable technique for preparing new porous hybrid materials has been tested in this paper. Hybrid ZnO films with two different organic dyes: Eosin-Y and Tetrasulphonated-Cu-phtalocyanine were prepared. Their physical and chemical properties as well as their dependence on the growth conditions were investigated. It is found that the type of dye has a big influence on the morphology and porosity of hybrid films. Open and connected pores are created in hybrid ZnO/Eosin-Y films while both open and closed pores coexist in hybrid ZnO/Tetrasulfonated-Cu-phthalocyanine. As one of the promising applications of hybrid materials is photovoltaic conversion of sunlight, photoelectrochemical characterization of hybrid films is also reported. Photocurrent generation owing to both contributions ZnO and Eosin-Y is observed in ZnO/Eosin-Y films but no photocurrent has been observed in ZnO/Tetrasulfonated-Cu-phthalocyanine films. SEM micrographs of hybrid ZnO films grown in aqueous bath; (Left) ZnO/Eosin-Y films grown at 70 C, -0.9 V (Right) ZnO/Ts-CuPc films grown at 70 C, -0.9 V. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Application of Genomic In Situ Hybridization in Horticultural Science

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Fahad Ramzan

2017-01-01

Full Text Available Molecular cytogenetic techniques, such as in situ hybridization methods, are admirable tools to analyze the genomic structure and function, chromosome constituents, recombination patterns, alien gene introgression, genome evolution, aneuploidy, and polyploidy and also genome constitution visualization and chromosome discrimination from different genomes in allopolyploids of various horticultural crops. Using GISH advancement as multicolor detection is a significant approach to analyze the small and numerous chromosomes in fruit species, for example, Diospyros hybrids. This analytical technique has proved to be the most exact and effective way for hybrid status confirmation and helps remarkably to distinguish donor parental genomes in hybrids such as Clivia, Rhododendron, and Lycoris ornamental hybrids. The genome characterization facilitates in hybrid selection having potential desirable characteristics during the early hybridization breeding, as this technique expedites to detect introgressed sequence chromosomes. This review study epitomizes applications and advancements of genomic in situ hybridization (GISH techniques in horticultural plants.

Genomic networks of hybrid sterility.

Science.gov (United States)

Turner, Leslie M; White, Michael A; Tautz, Diethard; Payseur, Bret A

2014-02-01

Hybrid dysfunction, a common feature of reproductive barriers between species, is often caused by negative epistasis between loci ("Dobzhansky-Muller incompatibilities"). The nature and complexity of hybrid incompatibilities remain poorly understood because identifying interacting loci that affect complex phenotypes is difficult. With subspecies in the early stages of speciation, an array of genetic tools, and detailed knowledge of reproductive biology, house mice (Mus musculus) provide a model system for dissecting hybrid incompatibilities. Male hybrids between M. musculus subspecies often show reduced fertility. Previous studies identified loci and several X chromosome-autosome interactions that contribute to sterility. To characterize the genetic basis of hybrid sterility in detail, we used a systems genetics approach, integrating mapping of gene expression traits with sterility phenotypes and QTL. We measured genome-wide testis expression in 305 male F2s from a cross between wild-derived inbred strains of M. musculus musculus and M. m. domesticus. We identified several thousand cis- and trans-acting QTL contributing to expression variation (eQTL). Many trans eQTL cluster into eleven 'hotspots,' seven of which co-localize with QTL for sterility phenotypes identified in the cross. The number and clustering of trans eQTL-but not cis eQTL-were substantially lower when mapping was restricted to a 'fertile' subset of mice, providing evidence that trans eQTL hotspots are related to sterility. Functional annotation of transcripts with eQTL provides insights into the biological processes disrupted by sterility loci and guides prioritization of candidate genes. Using a conditional mapping approach, we identified eQTL dependent on interactions between loci, revealing a complex system of epistasis. Our results illuminate established patterns, including the role of the X chromosome in hybrid sterility. The integrated mapping approach we employed is applicable in a broad

Hybridization and the evolution of reef coral diversity.

Science.gov (United States)

Vollmer, Steven V; Palumbi, Stephen R

2002-06-14

Hundreds of coral species coexist sympatrically on reefs, reproducing in mass-spawning events where hybridization appears common. In the Caribbean, DNA sequence data from all three sympatric Acropora corals show that mass spawning does not erode species barriers. Species A. cervicornis and A. palmata are distinct at two nuclear loci or share ancestral alleles. Morphotypes historically given the name Acropora prolifera are entirely F(1) hybrids of these two species, showing morphologies that depend on which species provides the egg for hybridization. Although selection limits the evolutionary potential of hybrids, F(1) individuals can reproduce asexually and form long-lived, potentially immortal hybrids with unique morphologies.

Hybrid mesons with auxiliary fields

International Nuclear Information System (INIS)

Buisseret, F.; Mathieu, V.

2006-01-01

Hybrid mesons are exotic mesons in which the color field is not in the ground state. Their understanding deserves interest from a theoretical point of view, because it is intimately related to nonperturbative aspects of QCD. Moreover, it seems that some recently detected particles, such as the π 1 (1600) and the Y(4260), are serious hybrid candidates. In this work, we investigate the description of such exotic hadrons by applying the auxiliary fields technique (also known as the einbein field method) to the widely used spinless Salpeter Hamiltonian with appropriate linear confinement. Instead of the usual numerical resolution, this technique allows to find simplified analytical mass spectra and wave functions of the Hamiltonian, which still lead to reliable qualitative predictions. We analyse and compare two different descriptions of hybrid mesons, namely a two-body q system with an excited flux tube, or a three-body qg system. We also compute the masses of the 1 -+ hybrids. Our results are shown to be in satisfactory agreement with lattice QCD and other effective models. (orig.)

Rin4 causes hybrid necrosis and race-specific resistance in an interspecific lettuce hybrid.

Science.gov (United States)

Jeuken, Marieke J W; Zhang, Ningwen W; McHale, Leah K; Pelgrom, Koen; den Boer, Erik; Lindhout, Pim; Michelmore, Richard W; Visser, Richard G F; Niks, Rients E

2009-10-01

Some inter- and intraspecific crosses may result in reduced viability or sterility in the offspring, often due to genetic incompatibilities resulting from interactions between two or more loci. Hybrid necrosis is a postzygotic genetic incompatibility that is phenotypically manifested as necrotic lesions on the plant. We observed hybrid necrosis in interspecific lettuce (Lactuca sativa and Lactuca saligna) hybrids that correlated with resistance to downy mildew. Segregation analysis revealed a specific allelic combination at two interacting loci to be responsible. The allelic interaction had two consequences: (1) a quantitative temperature-dependent autoimmunity reaction leading to necrotic lesions, lethality, and quantitative resistance to an otherwise virulent race of Bremia lactucae; and (2) a qualitative temperature-independent race-specific resistance to an avirulent race of B. lactucae. We demonstrated by transient expression and silencing experiments that one of the two interacting genes was Rin4. In Arabidopsis thaliana, RIN4 is known to interact with multiple R gene products, and their interactions result in hypersensitive resistance to Pseudomonas syringae. Site-directed mutation studies on the necrosis-eliciting allele of Rin4 in lettuce showed that three residues were critical for hybrid necrosis.

Graphene-based hybrid plasmonic modulator

International Nuclear Information System (INIS)

Shin, Jin-Soo; Kim, Jin-Soo; Tae Kim, Jin

2015-01-01

A graphene-based hybrid plasmonic modulator is designed based on an asymmetric double-electrode plasmonic waveguide structure. The photonic device consists of a monolayer graphene, a thin metal strip, and a thin dielectric layer that is inserted between the grapheme and the metal strip. By electrically tuning the graphene’s refractive index, the propagation loss of the hybrid long-range surface plasmon polariton strip mode in the proposed graphene-based hybrid plasmonic waveguide is switchable, and hence the intensity of the guided modes is modulated. The highest modulation depth is observed at the graphene’s epsilon-near-zero region. The device characteristics are characterized over the entire C-band (1.530–1.565 μm). (paper)

Hyper-cross-linked, hybrid membranes via interfacial polymerization

NARCIS (Netherlands)

Raaijmakers, Michiel

2015-01-01

Hyper-cross-linked, hybrid membranes consist of covalent networks of alternating organic and inorganic, or biological groups. This thesis reports on the preparation of such hybrid networks via interfacial polymerization. The structure-property relationships of the hybrid networks depend strongly on

Possible climate warming effects on vegetation, forests, biotic (insect, pathogene) disturbances and agriculture in Central Siberia for 1960- 2050

Science.gov (United States)

Tchebakova, N. M.; Parfenova, E. I.; Soja, A. J.; Lysanova, G. I.; Baranchikov, Y. N.; Kuzmina, N. A.

2012-04-01

Regional Siberian studies have already registered climate warming over the last half a century (1960-2010). Our analysis showed that winters are already 2-3°C warmer in the north and 1-2°C warmer in the south by 2010. Summer temperatures increased by 1°C in the north and by 1-2°C in the south. Change in precipitation is more complicated, increasing on average 10% in middle latitudes and decreasing 10-20% in the south, promoting local drying in already dry landscapes. Our goal was to summarize results of research we have done for the last decade in the context of climate warming and its consequences for biosystems in Central Siberia. We modeled climate change effects on vegetation shifts, on forest composition and agriculture change, on the insect Siberian moth (Dendrolimus suprans sibiricus Tschetv) and pathogene (Lophodermium pinastri Chev) ranges in Central Siberia for a century (1960-2050) based on historical climate data and GCM-predicted data. Principal results are: In the warmer and drier climate projected by these scenarios, Siberian forests are predicted to decrease and shift northwards and forest-steppe and steppe ecosystems are predicted to dominate over 50% of central Siberia due to the dryer climate by 2080. Permafrost is not predicted to thaw deep enough to sustain dark (Pinus sibirica, Abies sibirica, and Picea obovata) taiga. Over eastern Siberia, larch (Larix dahurica) taiga is predicted to continue to be the dominant zonobiome because of its ability to withstand continuous permafrost. The model also predicts new temperate broadleaf forest and forest-steppe habitats; At least half of central Siberia is predicted to be climatically suitable for agriculture at the end of the century although potential croplands would be limited by the availability of suitable soils agriculture in central Siberia would likely benefit from climate warming Crop production may twofold increase as climate warms during the century; traditional crops (grain, potato

The Curious Case of the "Refrigerator-TV": Similarity and Hybridization

Science.gov (United States)

Gibbert, Michael; Hampton, James A.; Estes, Zachary; Mazursky, David

2012-01-01

This article examines the role of similarity in the hybridization of concepts, focusing on hybrid products as an applied test case. Hybrid concepts found in natural language, such as "singer songwriter," typically combine similar concepts, whereas dissimilar concepts rarely form hybrids. The hybridization of dissimilar concepts in products such as…

Hybrid spread spectrum radio system

Science.gov (United States)

Smith, Stephen F [London, TN; Dress, William B [Camas, WA

2010-02-09

Systems and methods are described for hybrid spread spectrum radio systems. A method, includes receiving a hybrid spread spectrum signal including: fast frequency hopping demodulating and direct sequence demodulating a direct sequence spread spectrum signal, wherein multiple frequency hops occur within a single data-bit time and each bit is represented by chip transmissions at multiple frequencies.

Original Framework for Optimizing Hybrid Energy Supply

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Amevi Acakpovi

2016-01-01

Full Text Available This paper proposes an original framework for optimizing hybrid energy systems. The recent growth of hybrid energy systems in remote areas across the world added to the increasing cost of renewable energy has triggered the inevitable development of hybrid energy systems. Hybrid energy systems always pose a problem of optimization of cost which has been approached with different perspectives in the recent past. This paper proposes a framework to guide the techniques of optimizing hybrid energy systems in general. The proposed framework comprises four stages including identification of input variables for energy generation, establishment of models of energy generation by individual sources, development of artificial intelligence, and finally summation of selected sources. A case study of a solar, wind, and hydro hybrid system was undertaken with a linear programming approach. Substantial results were obtained with regard to how load requests were constantly satisfied while minimizing the cost of electricity. The developed framework gained its originality from the fact that it has included models of individual sources of energy that even make the optimization problem more complex. This paper also has impacts on the development of policies which will encourage the integration and development of renewable energies.

Specification of real-time automation systems with HybridUML; Spezifikation von Echtzeit-Automatisierungssystemen mit HybridUML

Energy Technology Data Exchange (ETDEWEB)

Berkenkoetter, K.; Bisanz, S.; Hannemann, U.; Peleska, J. [Univ. Bremen (Germany)

2004-07-01

Complex automation systems require specification formalisms supporting the description of real-time requirements with respect to both discrete and time-continuous observables. For this purpose, the authors have designed the HybridUML specification language. Discrete events, communication, and variable assignments are specified by state machines, timers, and invariant conditions. The time-continuous aspects of system behaviour are described by associating differential equations or time-dependent algebraic conditions with system states. The complexity of large systems is controlled by decomposing the specification into parallel components and hierarchical state machines. Instead of inventing a new language syntax, HybridUML is represented as a profile of the Unified Modeling Language UML 2.0. This allows to re-use the syntactic framework of well-accepted graphical UML constructs and development support provided by various UML case tools. The profile is associated with a precise language semantics linking unambiguous meaning to all HybridUML specifications. As a consequence, HybridUML specifications can be compiled into executable code which is suitable for execution in hard realtime on multi-processor computers. This serves both for the development of automation systems and for specification-based testing in real-time. This paper contains an introduction to HybridUML which is illustrated by an example from the field of automated train control. (orig.)

Hybrid Laminates for Application in North Conditions

Science.gov (United States)

Antipov, V. V.; Oreshko, E. I.; Erasov, V. S.; Serebrennikova, N. Yu.

2016-11-01

A hybrid aluminum-lithium alloy/SIAL laminate as a possible material for application in structures operated in North conditions is considered. The finite-element method is used for a buckling stability analysis of hybrid panels, bars, and plates. A technique allowing one to compare the buckling stability of multilayered hybrid plates is offered. Compression tests were run on a hybrid laminate wing panel as a prototype of the top panel of TU-204SM airplane made from a high-strength B95T2 aluminum alloy. It turned out that the lighter composite panel had a higher load-carrying capacity than the aluminum one. Results of investigation into the properties the hybrid aluminum-lithium alloy/SIAL laminate and an analysis of scientific-technical data on this subject showed that this composite material could be used in the elements of airframes, including those operated in north conditions.

Carboxylated nitrile butadiene rubber/hybrid filler composites

Directory of Open Access Journals (Sweden)

Ahmad Mousa

2012-08-01

Full Text Available The surface properties of the OSW and NLS are measured with the dynamic contact-angle technique. The x-ray photoelectron spectroscopy (XPS of the OSW reveals that the OSW possesses various reactive functional groups namely hydroxyl groups (OH. Hybrid filler from NLS and OSW were incorporated into carboxylated nitrile rubber (XNBR to produce XNBR hybrid composites. The reaction of OH groups from the OSW with COOH of the XNBR is checked by attenuated total reflectance spectra (ATR-IR of the composites. The degree of curing ΔM (maximum torque-minimum torque as a function of hybrid filler as derived from moving die rheometer (MDR is reported. The stress-strain behavior of the hybrid composites as well as the dynamic mechanical thermal analysis (DMTA is studied. Bonding quality and dispersion of the hybrid filler with and in XNBR are examined using scanning-transmission electron microscopy (STEM in SEM.

(D,T) Driven thorium hybrid blankets

International Nuclear Information System (INIS)

Al-Kusayer, T.A.; Khan, S.; Sahin, S.

1983-01-01

Recently, a project has started, with the aim to establish the neutronic performance and the basic design of an experimental fusionfission (hybrid) reactor facility, called AYMAN, in cylinderical geometry. The fusion reactor will have to be simulated by a (D,T) neutron generator. Fissile and fertile fuel will have to surround the neutron generator as a cylinderical blanket to simulate the boundary conditions of the hybrid blanket in a proper way. This geometry is consistent with Tandem Mirror Hybrid Blanket design and with most of the ICF blanket designs. A similar experimental installation will become operational around 1984 at the Swiss Federal Institute of Technology in Lausanne, Switzerland known under the project LOTUS. Due to the limited dimensions of the experimental cavity of the LOTUS-hybrid reactor, the LOTUS blankets have to be designed in plane geometry. Also, the bulky form of the Haefely neutron generator of the LOTUS facility obliges one to design a blanket in the plane geometry. This results in a vacuum left boundary conditions for the LOTUS blanket. The importance of a reflecting left boundary condition on the overall neutronic performance of a hybrid blanket has been analyzed in previous work in detail

Travelling Waves in Hybrid Chemotaxis Models

KAUST Repository

Franz, Benjamin

2013-12-18

Hybrid models of chemotaxis combine agent-based models of cells with partial differential equation models of extracellular chemical signals. In this paper, travelling wave properties of hybrid models of bacterial chemotaxis are investigated. Bacteria are modelled using an agent-based (individual-based) approach with internal dynamics describing signal transduction. In addition to the chemotactic behaviour of the bacteria, the individual-based model also includes cell proliferation and death. Cells consume the extracellular nutrient field (chemoattractant), which is modelled using a partial differential equation. Mesoscopic and macroscopic equations representing the behaviour of the hybrid model are derived and the existence of travelling wave solutions for these models is established. It is shown that cell proliferation is necessary for the existence of non-transient (stationary) travelling waves in hybrid models. Additionally, a numerical comparison between the wave speeds of the continuum models and the hybrid models shows good agreement in the case of weak chemotaxis and qualitative agreement for the strong chemotaxis case. In the case of slow cell adaptation, we detect oscillating behaviour of the wave, which cannot be explained by mean-field approximations. © 2013 Society for Mathematical Biology.

In situ hybridization; principles and applications: review article

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Zahra Nozhat

2015-06-01

Full Text Available In situ hybridization (ISH is a method that uses labeled complementary single strand DNA or RNA to localize specific DNA or RNA sequences in an intact cell or in a fixed tissue section. The main steps of ISH consist of: probe selection, tissue or sample preparation, pre-hybridization treatment, hybridization and washing, detection and control procedure. Probe selection is one of the important aspects of successful hybridization. ISH sensitivity and specificity can be influenced by: probe construct, efficiency of labeling, percentage of GC, probe length and signal detection systems. Different methods such as nick translation, random priming, end tailing and T4 DNA polymerase replacement are used for probe generation. Both radioactive and non-radioactive labels can be used in order to probe labeling. Nucleic acid maintenance in samples, prevention of morphological changes of samples and probe penetration into tissue section are the main aims of sample preparation step. Then, a small amount of solution containing probe, is added on slides containing tissue sections for hybridization process, then slides are incubated overnight. Next day, washes are carried out to remove the probes which are not bound to target DNA or RNA. Finally, in order to be sure that the observed labeling is specific to the target sequence, using several control procedures is very important. Various techniques based on ISH consist of: Fluorescence in situ hybridization (FISH, chromogenic in situ hybridization (CISH, genomic in situ hybridization (GISH, comparative genomic hybridization (CGH, spectral karyotyping (SKY and multiplex fluorescence in situ hybridization (MFISH. One of the most common techniques of ISH is fluorescence in situ hybridization. FISH can be used to: 1 detect small deletions and duplications that are not visible using microscope analysis, 2 detect how many chromosomes of a certain type are present in each cell and 3 confirm rearrangements that are

Hydraulic Hybrid Parcel Delivery Truck Deployment, Testing & Demonstration

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