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Sample records for montane oyamel fir

  1. Montane conifer fuel dynamics, Yosemite National Park

    Science.gov (United States)

    van Wagtendonk, J.W.; Moore, P.E.

    1997-01-01

    Litter and woody fuel accumulation rates over 7 years for 7 montane Sierra Nevada conifer species, including giant sequoia, ponderosa pine, sugar pine, Jeffrey pine, incense-cedar and white fir. Data are from four sites per size class per species with four size classes each. Nonspatial, georeferenced.

  2. Estimación de carbono almacenado en bosques de oyamel y ciprés en Texcoco, Estado de México

    Directory of Open Access Journals (Sweden)

    Yunuen Bolaños González

    2017-01-01

    Full Text Available Las emisiones de carbono (C a la atmósfera, así como sus reservorios, en el sector de agricultura, silvicultura y otros usos del suelo son significativas en el balance global del ciclo del carbono; sin embargo, a pesar de esta importancia, es el sector con la mayor incertidumbre en el balance global debido principalmente a la falta de conocimiento preciso de los factores de emisión, por lo que se requiere mayor investigación en el tema. Debido a lo anterior, este trabajo tuvo como objetivo estimar el C almacenado en los cinco depósitos considerados en ecosistemas forestales: biomasa viva sobre el suelo, biomasa viva debajo del suelo, madera muerta sobre el suelo, mantillo y carbono orgánico del suelo (COS en dos sitios de muestreo ubicados en las faldas del Monte Tláloc, Texcoco, Estado de México: el primero en un bosque de oyamel (Abies religiosa y el segundo en un bosque de ciprés (Cupressus lusitanica. El promedio de la densidad de carbono en el bosque de oyamel en los cinco depósitos estimados fue de 376 Mg ha‑1, siendo el depósito más importante el de biomasa aérea (59%, seguido del COS (22%; en tanto que en el bosque de ciprés fue de 205 Mg ha-1, siendo el depósito con mayor densidad el COS (50%, seguido de biomasa aérea (36%. Los valores de densidad de carbono para biomasa aérea en el caso de bosque de oyamel fueron superiores a los reportados en otros trabajos; lo cual se explica por la existencia de árboles de grandes dimensiones de esta especie en el sitio de muestreo, lo cual nos da una idea precisa del potencial como almacén de carbono que este tipo de vegetación tiene cuando llegan a estados maduros.

  3. Novel FIR Inversion with Only FIRS

    CERN Document Server

    Chalmers, G

    2005-01-01

    The inversion of an FIR data sampling is usually stated to be possible with the use of a potentially unstable IIR, and in particular circumstances. It is possible to accomplish the same inversion with the doubling of an FIR sampling and with only FIRs for the sampling and the inversion. This note presents the configuration, which appently is not in the literature, for perfect signal reconstruction.

  4. Tree diversity in sub-montane and lower montane primary rain forests in Central Sulawesi

    NARCIS (Netherlands)

    Culmsee, H.; Pitopang, R.

    2009-01-01

    The tree diversity of sub-montane and lower montane primary forests is studied in plot-based inventories on two sites in Lore Lindu National Park, Central Sulawesi. Out of 166 species in total, 50 % are new records for Sulawesi (19 %) or the Central Sulawesi province (31 %). Species richness

  5. Leader growth in Nordman fir christmas trees

    DEFF Research Database (Denmark)

    Christensen, Claus Jerram; Pedersen, Lars Bo

    Leader Griowth in Nordman fir Christmas trees: Growth visualization and effects of fertilization, irrigation and drought......Leader Griowth in Nordman fir Christmas trees: Growth visualization and effects of fertilization, irrigation and drought...

  6. Taxonomic and functional ecology of montane ants

    Directory of Open Access Journals (Sweden)

    Tom Rhys Bishop

    2017-04-01

    Full Text Available Why is biological diversity distributed in the way that it is? This question has been central to ecology and biogeography for centuries and is of great importance for pure and applied reasons. I use a functional trait view of ecology to complement standard sampling protocols to better understand the distribution and structure of ant (Hymenoptera: Formicidae diversity across mountains. I use a long-term dataset of ant diversity and abundance, combined with a recently collected morphological trait dataset to examine how the alpha and beta diversity of ants responds to changes in temperature along an extensive elevational gradient in southern Africa. In addition, I link morphological thermoregulatory traits to each other and to the environment with a new database of ant elevational abundances from across the globe. Finally, I analyse how physiological thermal tolerances vary and constrain foraging patterns in montane ants. I find that temperature is a strong driver of both alpha and beta diversity patterns. In addition, morphological traits such as colour and body size are found to have a significant relationship to ambient temperatures. This relationship also implies that the relative abundances of different ant species change depending on their thermoregulatory traits (colour and body size and the surrounding thermal environment. Furthermore, the critical thermal minimum (CTmin of the ant species investigated and the lowest environmental temperatures are found to be key in constraining foraging activity patterns. The data presented here strengthen and link existing ideas about how thermoregulation can influence ecological communities and also suggests important ways in which diversity patterns may change in the future.

  7. An Orthogonal Least Squares Based Approach to FIR Designs

    Institute of Scientific and Technical Information of China (English)

    Xiao-Feng Wu; Zi-Qiang Lang; Stephen A Billings

    2005-01-01

    This paper is concerned with the application of forward Orthogonal Least Squares (OLS) algorithm to the design of Finite Impulse Response (FIR) filters. The focus of this study is a new FIR filter design procedure and to compare this with traditional methods known as the fir2() routine provided by MATLAB.

  8. Montane and cloud forest specialists among neotropical Xylaria species

    Science.gov (United States)

    D. Jean Lodge; Thomas L& #230; ss& #248; e; M. Catherine Aime; Terry W. Henkel; M. Catherine Aime; Terry W. Henkel

    2008-01-01

    We compared recored of neotropical Xylaria species among Belize, Ecuador, the Guianas, Mexico, Puerto Rico and Venezuela to determine if there were neotropical taxa consistently found only in cloud forest or high montane forests that might be endangered by climate change.

  9. Douglas-Fir Tussock Moth- and Douglas-Fir Beetle-Caused Mortality in a Ponderosa Pine/Douglas-Fir Forest in the Colorado Front Range, USA

    Directory of Open Access Journals (Sweden)

    José F. Negrón

    2014-12-01

    Full Text Available An outbreak of the Douglas-fir tussock moth, Orgyia pseudotsugata McDunnough, occurred in the South Platte River drainage on the Pike-San Isabel National Forest in the Colorado Front Range attacking Douglas-fir, Pseudotsuga menziesii (Mirb. Franco. Stocking levels, species composition, and tree size in heavily and lightly defoliated stands were similar. Douglas-fir tussock moth defoliation resulted in significant Douglas-fir mortality in the heavily defoliated stands, leading to a change in dominance to ponderosa pine, Pinus ponderosa Lawson. Douglas-fir beetle, Dendroctonus pseudotsuqae Hopkins, populations increased following the defoliation event but caused less mortality, and did not differ between heavily and lightly defoliated stands. Douglas-fir tussock moth-related mortality was greatest in trees less than 15 cm dbh (diameter at 1.4 m above the ground that grew in suppressed and intermediate canopy positions. Douglas-fir beetle-related mortality was greatest in trees larger than 15 cm dbh that grew in the dominant and co-dominant crown positions. Although both insects utilize Douglas-fir as its primary host, stand response to infestation is different. The extensive outbreak of the Douglas-fir tussock moth followed by Douglas-fir beetle activity may be associated with a legacy of increased host type growing in overstocked conditions as a result of fire exclusion.

  10. Frequency domain FIR and IIR adaptive filters

    Science.gov (United States)

    Lynn, D. W.

    1990-01-01

    A discussion of the LMS adaptive filter relating to its convergence characteristics and the problems associated with disparate eigenvalues is presented. This is used to introduce the concept of proportional convergence. An approach is used to analyze the convergence characteristics of block frequency-domain adaptive filters. This leads to a development showing how the frequency-domain FIR adaptive filter is easily modified to provide proportional convergence. These ideas are extended to a block frequency-domain IIR adaptive filter and the idea of proportional convergence is applied. Experimental results illustrating proportional convergence in both FIR and IIR frequency-domain block adaptive filters is presented.

  11. Projecting the Hydrologic Impacts of Climate Change on Montane Wetlands.

    Science.gov (United States)

    Lee, Se-Yeun; Ryan, Maureen E; Hamlet, Alan F; Palen, Wendy J; Lawler, Joshua J; Halabisky, Meghan

    2015-01-01

    Wetlands are globally important ecosystems that provide critical services for natural communities and human society. Montane wetland ecosystems are expected to be among the most sensitive to changing climate, as their persistence depends on factors directly influenced by climate (e.g. precipitation, snowpack, evaporation). Despite their importance and climate sensitivity, wetlands tend to be understudied due to a lack of tools and data relative to what is available for other ecosystem types. Here, we develop and demonstrate a new method for projecting climate-induced hydrologic changes in montane wetlands. Using observed wetland water levels and soil moisture simulated by the physically based Variable Infiltration Capacity (VIC) hydrologic model, we developed site-specific regression models relating soil moisture to observed wetland water levels to simulate the hydrologic behavior of four types of montane wetlands (ephemeral, intermediate, perennial, permanent wetlands) in the U. S. Pacific Northwest. The hybrid models captured observed wetland dynamics in many cases, though were less robust in others. We then used these models to a) hindcast historical wetland behavior in response to observed climate variability (1916-2010 or later) and classify wetland types, and b) project the impacts of climate change on montane wetlands using global climate model scenarios for the 2040s and 2080s (A1B emissions scenario). These future projections show that climate-induced changes to key driving variables (reduced snowpack, higher evapotranspiration, extended summer drought) will result in earlier and faster drawdown in Pacific Northwest montane wetlands, leading to systematic reductions in water levels, shortened wetland hydroperiods, and increased probability of drying. Intermediate hydroperiod wetlands are projected to experience the greatest changes. For the 2080s scenario, widespread conversion of intermediate wetlands to fast-drying ephemeral wetlands will likely reduce

  12. Management of silver fir (Abies alba Mill.) in Slovenia

    OpenAIRE

    Bončina, Andrej; Ficko, Andrej; Klopčič, Matija; Matijašič, Dragan; Poljanec, Aleš

    2009-01-01

    In the paper, we analysed the structure and developmental characteristics of forest stands with silver fir in Slovenia, the management and cut in four forest site strata, where silver fir occurs. We used databases from the Slovenia Forest Service. In growing stock (GS) of silver fir, large (dbh=30-49cm) and very large (d=50 cm and more) diameter trees account for 84.9 % at the national level. The highest share of very large diameter silver fir trees (45 %) is in Dinaric silver fir forests and...

  13. A New FIR Filter for State Estimation and Its Application

    Institute of Scientific and Technical Information of China (English)

    Pyung-Soo Kim; Myung-Eui Lee

    2007-01-01

    This paper proposes a new FIR (finite impulse response) filter under a least squares criterion using a forgetting factor. The proposed FIR filter does not require information of the noise covariances as well as the initial state, and has some inherent properties such as time-invariance, unbiasedness and deadbeat. The proposed FIR filter is represented in a batch form and then a recursive form as an alternative form. From discussions about the choice of a forgetting factor and a window length, it is shown that they can be considered as useful parameters to make the estimation performance of the proposed FIR filter as good as possible. It is shown that the proposed FIR filter can outperform the existing FIR filter with incorrect noise covariances via computer simulations. Finally, as a useful application, an image sequence stabilization problem is considered. Through this application, the FIR filtering based approach is shown to be superior to the Kalman filtering based approach.

  14. Tall oil precursors of Douglas fir

    Science.gov (United States)

    Daniel O. Foster; Duane F. Zinkel; Anthony H. Conner

    1980-01-01

    The sapwood and heartwood extractives of Douglas fir [Pseudotsuga menziesii (Mirb.) Franco] and the tall oil in the kraft black liquor were characterized. On pulping, isomerization and conversion of conjugated resin acids to dehydroabietic acid was observed. Recovery of both fatty and resin acids from pulping was lower than predicted from the extractive composition....

  15. Contribution of Soil Fauna to Foliar Litter-Mass Loss in Winter in an Ecotone between Dry Valley and Montane Forest in the Upper Reaches of the Minjiang River.

    Directory of Open Access Journals (Sweden)

    Yan Peng

    Full Text Available Litter decomposition during winter can provide essential nutrients for plant growth in the subsequent growing season, which plays important role in preventing the expansion of dry areas and maintaining the stability of ecotone ecosystems. However, limited information is currently available on the contributions of soil fauna to litter decomposition during winter in such ecosystems. Therefore, a field experiment that included litterbags with two different mesh sizes (0.04 mm and 3 mm was conducted to investigate the contribution of soil fauna to the loss of foliar litter mass in winter from November 2013 to April 2014 along the upper reaches of the Minjiang River. Two litter types of the dominant species were selected in each ecosystem: cypress (Cupressus chengiana and oak (Quercus baronii in ecotone; cypress (Cupressus chengiana and clovershrub (Campylotropis macrocarpa in dry valley; and fir (Abies faxoniana and birch (Betula albosinensis in montane forest. Over one winter incubation, foliar litter lost 6.0%-16.1%, 11.4%-26.0%, and 6.4%-8.5% of initial mass in the ecotone, dry valley and montane forest, respectively. Soil fauna showed obvious contributions to the loss of foliar litter mass in all of the ecosystems. The highest contribution (48.5%-56.8% was observed in the ecotone, and the lowest contribution (0.4%-25.8% was observed in the montane forest. Compared with other winter periods, thawing period exhibited higher soil fauna contributions to litter mass loss in ecotone and dry valley, but both thawing period and freezing period displayed higher soil fauna contributions in montane forest. Statistical analysis demonstrated that the contribution of soil fauna was significantly correlated with temperature and soil moisture during the winter-long incubation. These results suggest that temperature might be the primary control factor in foliar litter decomposition, but more active soil fauna in the ecotone could contribute more in litter

  16. Montane wetland water chemistry, Uinta Mountains, Utah

    Science.gov (United States)

    Severson, K. S.; Matyjasik, M.; Ford, R. L.; Hernandez, M. W.; Welsh, S. B.; Summers, S.; Bartholomew, L. M.

    2009-12-01

    part of the watershed, gradually changing to bicarbonate in the lower part of the watershed. The creek water also show a relatively small increase in total dissolved solids from 10 mg/L in the upper basin to 18 mg/L in the lower basin. Dissolved oxygen, potassium, and chlorides also decrease along the creek flow path, while calcium and sulfates increase. Values of pH fluctuate more along the length of the channel as the creek receives water discharging from the wetlands. An interesting geomorphic characteristic of these montane wetlands is a distinctive compartmentalization by a system of peaty flarks and strings, typically oriented perpendicular to the direction of surface-water flow. Water samples collected from piezometers contain much higher concentrations of all ions compared to surface-water samples from the flarks. It is believed that deeper portions of the peat work as highly isolated flow cells, storing water for an extended period of time, resulting in locally increased ionic concentrations. Future work will attempt to clarify and test this hypothesis.

  17. BIOGEOGRAPHICAL IMPLICATIONS OF SOME PLANT SPECIES FROM A TROPICAL MONTANE RAIN FOREST IN SOUTHERN YUNNAN

    Institute of Scientific and Technical Information of China (English)

    ZHU Hua

    2004-01-01

    A pristine montane rain forest was recently discovered from Mengsong of Xishuangbanna in the southern Yunnan.It attracts botanists that many primitive plant taxa across various life forms were co-existed in the montane rain forest.In order to know the biogeography of the montane rain forest,distribution patterns of some species of biogeographical importance from the montane forest were enumerated and their biogeographical implications were discussed with geological explanation.It was concluded that the montane rain forest in the southern Yunnan has strong affinity to montane rain forests in Sumatra or Southeast Asia in broad sense.It was tentatively suggested that Sumatra could be once connected to Myanmar and drifted away due to northward movement of continental Asia by bumping of India plate.

  18. Unveiling the Hidden Bat Diversity of a Neotropical Montane Forest

    OpenAIRE

    Chaverri, Gloriana; Garin, Inazio; Alberdi, Antton; Jimenez, Lide; Castillo-Salazar, Cristian; Aihartza, Joxerra

    2016-01-01

    Mountain environments, characterized by high levels of endemism, are at risk of experiencing significant biodiversity loss due to current trends in global warming. While many acknowledge their importance and vulnerability, these ecosystems still remain poorly studied, particularly for taxa that are difficult to sample such as bats. Aiming to estimate the amount of cryptic diversity among bats of a Neotropical montane cloud forest in Talamanca Range—south-east Central America—, we performed a ...

  19. Birds, Montane forest, State of Rio de Janeiro, Southeastern Brazil

    Directory of Open Access Journals (Sweden)

    Foster, A.

    2009-01-01

    Full Text Available Field surveys in montane Atlantic forest of Rio de Janeiro state, Brazil, provided a list of 82 bird species in four sitesvisited. Our protocol relied on standardized use of mist nets and observations. The birds recorded include 40 Atlanticforest endemics, three globally and two nationally Vulnerable species, and two regionally Endangered species. Data onspecies elevation are included and discussed. This work enhances baseline knowledge of these species to assist futurestudies in these poorly understood, but biologically important areas.

  20. Remote sensing of balsam fir forest vigor

    Science.gov (United States)

    Luther, Joan E.; Carroll, Allen L.

    1997-12-01

    The potential of remote sensing to monitor indices of forest health was tested by examining the spectral separability of plots with different balsam fir, Abies balsamea (L.) Mill, vigor. Four levels of vigor were achieved with controlled experimental manipulations of forest stands. In order of increasing vigor, the treatments were root pruning, control, thinning and thinning in combination with fertilization. Spectral reflectance of branchlets from each plot were measured under laboratory conditions using a field portable spectroradiometer with a spectral range from 350 - 2500 nm. Branchlets were discriminated using combinations of factor and discriminant analyses techniques with classification accuracies of 91% and 83% for early and late season analyses, respectively. Relationships between spectral reflectance measurements at canopy levels, stand vigor, and foliage quality for an insect herbivore will be analyzed further in support of future large scale monitoring of balsam fir vulnerability to insect disturbance.

  1. Community characteristics of tropical montane evergreen forest and tropical montane dwarf forest in Bawangling National Nature Reserve on Hainan Island, South China

    OpenAIRE

    Wenxing Long; Runguo Zang; Yi Ding

    2011-01-01

    Both tropical montane evergreen forest (TMEF) and tropical montane dwarf forest (TMDF) are typical tropical cloud forests on Hainan Island. To compare community structure and species diversity be-tween these two forest types, we established eight and ten plots (each with 2,500 m2 in area) in TMEF and TMDF, respectively, in Bawangling National Nature Reserve on Hainan Island, South China. We investigated each individual plant with diameter at breast height (DBH) ≥1 cm including trees, shrubs a...

  2. Investigating drought vulnerability using stable water isotopes and tritium in a montane system

    Science.gov (United States)

    Thaw, Melissa; Visser, Ate; Deinhart, Amanda; Bibby, Richard; Everhart, Anthony; Sharp, Mike; Conklin, Martha

    2017-04-01

    We combined measurements of water stable isotopes (d18O and d2H) with measurements of tritium (3H) to track water from precipitation through the subsurface and vegetation. Our study examined drought vulnerability in terms of vegetation water sources and subsurface storage in two montane sites, seasonally, using stable isotopes and tritium. Relative proportions of evapotranspiration sources were determined using two-tracer (d18O and 3H), three component mixing models. The two sites, located in the Southern Sierra Critical Zone Observatory, California, USA, are Mediterranean in climate, straddling the rain-snow transition zone where the upper elevation site receives most of its precipitation as winter snow. Over the study period, summer 2015 followed four years of severe snow drought; summer 2016 followed a slightly below average winter. The lower elevation site experienced severe drought-induced tree mortality over this time. Preliminary results show severe snow drought conditions and summer precipitation affected the proportions of source water used by vegetation due to the ability of vegetation to change sources when new water became available. Both stable isotopes and tritium reflect seasonal shifts in vegetation water sources, as well as species vulnerability and tolerance to drought. Xylem water sampled from Abies concolor (white fir) and Arctostaphylos patula (manzanita) responded the most quickly to changes in available water sources compared to Pinus jeffreyi (Jeffrey pine) and Calocedrus decurrens (incense cedar). Abies concolor and Arctostaphylos patula responded more dramatically to summer soil evaporation by accessing summer rain and deep water sources more quickly. Abies concolor also responded more dramatically to changes in snowpack during winter. During severe drought conditions, Arctostaphylos's ability to tap into a wide range of water sources coincided with drought tolerance (100% survival rate), while mortality for Pinus ponderosa and Calocedrus

  3. Balsam Fir Wooly Adlegid Survey on CVNWR 2009

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — On July 17, 2009 Amber Myers and I conducted a survey to check the status of Balsam Fir Wooly Adelgid on one hundred Balsam Fir Trees off of Freeland Trail. We...

  4. Structure and floristic similarities of upper montane forests in Serra Fina mountain range, southeastern Brazil

    Directory of Open Access Journals (Sweden)

    Leonardo Dias Meireles

    2015-03-01

    Full Text Available The upper montane forests in the southern and southeastern regions of Brazil have an unusual and discontinuous geographic distribution at the top of the Atlantic coastal mountain ranges. To describe the floristic composition and structure of the Atlantic Forest near its upper altitudinal limit in southeastern Brazil, 30 plots with 10 × 10 m were installed in three forest sites between 2,200 and 2,300 m.a.s.l. at Serra Fina. The floristic composition and phytosociological structure of this forest were compared with other montane and upper montane forests. In total, 704 individuals were included, belonging to 24 species, 15 families, and 19 genera. Myrsinaceae, Myrtaceae, Symplocaceae, and Cunoniaceae were the most important families, and Myrsine gardneriana, Myrceugenia alpigena, Weinmannia humilis, and Symplocos corymboclados were the most important species. The three forest sites revealed differences in the abundance of species, density, canopy height, and number of stems per individual. The upper montane forests showed structural similarities, such as lower richness, diversity, and effective number of species, and they tended to have higher total densities and total dominance per hectare to montane forests. The most important species in these upper montane forests belong to Austral-Antartic genera or neotropical and pantropical genera that are typical of montane areas. The high number of species shared by these forests suggests past connections between the vegetation in southern Brazilian high-altitude areas.

  5. Unveiling the Hidden Bat Diversity of a Neotropical Montane Forest

    Science.gov (United States)

    Chaverri, Gloriana; Garin, Inazio; Alberdi, Antton; Jimenez, Lide; Castillo-Salazar, Cristian; Aihartza, Joxerra

    2016-01-01

    Mountain environments, characterized by high levels of endemism, are at risk of experiencing significant biodiversity loss due to current trends in global warming. While many acknowledge their importance and vulnerability, these ecosystems still remain poorly studied, particularly for taxa that are difficult to sample such as bats. Aiming to estimate the amount of cryptic diversity among bats of a Neotropical montane cloud forest in Talamanca Range—south-east Central America—, we performed a 15-night sampling campaign, which resulted in 90 captured bats belonging to 8 species. We sequenced their mitochondrial cytochrome c oxidase subunit I (COI) and screened their inter- and intraspecific genetic variation. Phylogenetic relations with conspecifics and closely related species from other geographic regions were established using Maximum Likelihood and Bayesian inference methods, as well as median-joining haplotype networks. Mitochondrial lineages highly divergent from hitherto characterized populations (> 9% COI dissimilarity) were found in Myotis oxyotus and Hylonycteris underwoodi. Sturnira burtonlimi and M. keaysi also showed distinct mitochondrial structure with sibling species and/or populations. These results suggest that mountains in the region hold a high degree of endemicity potential that has previously been ignored in bats. They also warn of the high extinction risk montane bats may be facing due to climatic change, particularly in isolated mountain systems like Talamanca Range. PMID:27706168

  6. Molecular clouds photoevaporation and FIR line emission

    Science.gov (United States)

    Vallini, L.; Ferrara, A.; Pallottini, A.; Gallerani, S.

    2017-01-01

    With the aim of improving predictions on far infrared (FIR) line emission from Giant Molecular Clouds (GMC), we study the effects of photoevaporation (PE) produced by external far-ultraviolet (FUV) and ionizing (extreme-ultraviolet, EUV) radiation on GMC structure. We consider three different GMCs with mass in the range M_GMC = 10^{3-6} {M_{⊙}}. Our model includes: (i) an observationally-based inhomogeneous GMC density field, and (ii) its time evolution during the PE process. In the fiducial case (MGMC ≈ 105M⊙), the photoevaporation time (tpe) increases from 1 Myr to 30 Myr for gas metallicity Z=0.05-1 Z_{⊙}, respectively. Next, we compute the time-dependent luminosity of key FIR lines tracing the neutral and ionized gas layers of the GMCs, ([C II] at 158 {μ m}, [O III] at 88 μ m) as a function of G0, and Z until complete photoevaporation at tpe. We find that the specific [C II] luminosity is almost independent on the GMC model within the survival time of the cloud. Stronger FUV fluxes produce higher [C II] and [O III] luminosities, however lasting for progressively shorter times. At Z = Z⊙ the [C II] emission is maximized (L_CII≈ 10^4 {L_{⊙}} for the fiducial model) for tpopulations.

  7. Molecular clouds photoevaporation and FIR line emission

    CERN Document Server

    Vallini, L; Pallottini, A; Gallerani, S

    2016-01-01

    With the aim of improving predictions on the far infrared (FIR) line emission from Giant Molecular Clouds (GMC), we have studied the effects of photoevaporation (PE) produced by external far-ultraviolet (FUV) and ionizing (extreme-ultraviolet, EUV) radiation on the GMC structure. Our model includes: (i) an observationally-based inhomogeneous GMC density field, and (ii) its time evolution during the PE process. We find that the photoevaporation timescale, $t_{pe}$, of a typical GMC ($M_{\\rm GMC}=9 \\times 10^{4}\\,\\rm{M_{\\odot}}$) is in the range $1-30$ Myr, for gas metallicity $Z=0.05-1\\,\\rm Z_{\\odot}$, respectively. At fixed metallicity, $t_{pe}$ decreases for higher FUV fluxes, $G_0$, due to the larger temperature of the photodissociation region (PDR). The presence of EUV radiation is important at $Z<0.2\\,\\rm{Z_{\\odot}}$, when the size of the HII layer becomes comparable to the cloud radius. We then compute the time-dependent luminosity (for which we give fitting formulae) of several key FIR lines ([CII], ...

  8. Effect of Continuous Plantation of Chinese Fir on Soil Fertility

    Institute of Scientific and Technical Information of China (English)

    DINGYING-XIANG; CHENJIN-LIN

    1995-01-01

    The changes in soil fertility under continuous plantation of Chinese fir were studied by comparing soil samples from different forest stands:the first and second plantations of Chinese fir,evergreen broad-leaved forests,and clear-cut and burnt Chinese fir land located at Xihou Village,Nanping of Fujian Province.The soils were humic red soil originated from weathered coarse granite of the Presinian system.Soil pH,CEC,base saturation ,exchangeable Ca2+,exchangeable Mg2+ and A1-P declined after continuous plantation of Chinese fir.The same trends were also found in the soils under broad-leaved stands and slash burnt lands.The explantation was that not merely the biological nature of the Chinese fir itself but the natural leaching of nutrients,soil erosion and nutrient losses due to clear cutting and slash burning of the preceduing plantation caused the soil deterioration .Only some of main soil nutrients decreased after continuous plantation of Chinese fir,depending on specific silvicultural system,which was different from the conclusions in some other reports which showed that all main nutrients,such as OM,total N,available P and available K decreased,Some neccessary step to make up for the lost base,to apply P fertilizer and to avoid buring on clear cut lands could be taken to prevent soil degradation and yield decline in the system of continuous plantation of Chinese fir.

  9. Effect of Allelochemicals of Chinese—fir root extracted by supercritical CO2 extraction on Chinese fir

    Institute of Scientific and Technical Information of China (English)

    LINSi-zu; CAOGuang-qiu; DULing; WANGAi-ping

    2003-01-01

    Allelochemicals of Chinese-fir root was extracted by technology of supercritical CO2 extraction under orthogonal experiment design, and it was used to analyze allelopathic activity of Chinese-fir through bioassay of seed germination, The results showed that as to the available rate of allelochemicals, the pressure and temperature of extraction were the most im-portant factors, The allelochemicals of Chinese-fir root extracted by pure CO2 and ethanol mixed with CO2 have different al-lelopathic activities to seed germination, and the allelochemicals extracted by ethanol mixed with CO2 had stronger inhibitory effects on seed Qermination than that extracted by pure CO2.

  10. Simulating land-cover change in Montane mainland southeast Asia.

    Science.gov (United States)

    Fox, Jefferson; Vogler, John B; Sen, Omer L; Giambelluca, Thomas W; Ziegler, Alan D

    2012-05-01

    We used the conversion of land use and its effects (CLUE-s) model to simulate scenarios of land-cover change in Montane mainland southeast Asia (MMSEA), a region in the midst of transformation due to rapid intensification of agriculture and expansion of regional trade markets. Simulated changes affected approximately 10 % of the MMSEA landscape between 2001 and 2025 and 16 % between 2001 and 2050. Roughly 9 % of the current vegetation, which consists of native species of trees, shrubs, and grasses, is projected to be replaced by tree plantations, tea, and other evergreen shrubs during the 50 years period. Importantly, 4 % of this transition is expected to be due to the expansion of rubber (Hevea brasiliensis), a tree plantation crop that may have important implications for local-to-regional scale hydrology because of its potentially high water consumption in the dry season.

  11. Effects of tropical montane forest disturbance on epiphytic macrolichens

    Energy Technology Data Exchange (ETDEWEB)

    Benitez, Angel [Instituto de Ecologia, Herbario HUTPL, Universidad Tecnica Particular de Loja, San Cayetano s/n, Loja (Ecuador); Prieto, Maria, E-mail: maria.prieto@urjc.es [Area de Biodiversidad y Conservacion, ESCET, Universidad Rey Juan Carlos, Mostoles, E-28933, Madrid (Spain); Gonzalez, Yadira [Instituto de Ecologia, Herbario HUTPL, Universidad Tecnica Particular de Loja, San Cayetano s/n, Loja (Ecuador); Aragon, Gregorio [Area de Biodiversidad y Conservacion, ESCET, Universidad Rey Juan Carlos, Mostoles, E-28933, Madrid (Spain)

    2012-12-15

    The high diversity of epiphytes typical of undisturbed montane tropical forests has been negatively affected by continuous deforestation and forest conversion to secondary vegetation. Macrolichens are an important component of these epiphytes. Because their physiology is strongly coupled to humidity and solar radiation, we hypothesized that microclimatic changes derived from forest clearing and logging can affect the diversity of these poikilohydric organisms. In southern Ecuador, we examined three types of forests according to a disturbance gradient (primary forests, secondary forests, and monospecific forests of Alnus acuminata) for the presence/absence and coverage of epiphytic macrolichens that we identified on 240 trees. We found that total richness tended to decrease when the range of the disturbance increased. The impoverishment was particularly drastic for 'shade-adapted lichens', while the richness of 'heliophytic lichens' increased in the drier conditions of secondary growth. Epiphytic composition also differed significantly among the three types of forests, and the similarity decreased when the range of the disturbance was greater. We concluded that a span of 40 years of recovery by secondary vegetation was not enough to regenerate the diversity of epiphytic macrolichens that was lost due to forest disturbances. -- Highlights: Black-Right-Pointing-Pointer Tropical montane forest disturbance drastically reduced macrolichen diversity. Black-Right-Pointing-Pointer Species loss was most severe for the 'shade-adapted lichens' because high radiation is harmful to them. Black-Right-Pointing-Pointer In secondary forests lichen diversity of native forests was not regenerated. Black-Right-Pointing-Pointer The protection of remnants of primary tropical forest might help to preserve a diverse community of epiphytic macrolichens.

  12. NEEDLE ANATOMY CHANGES WITH INCREASING TREE AGE IN DOUGLAS FIR

    Science.gov (United States)

    Morphological differences between old growth and sapling (Pseudotsuga menziesii, (Mirb.) Franco) Douglas fir trees may extend to differences in needle anatomy. We used microscopy with image analysis to compare and quantify anatomical parameters in cross-sections of previous year...

  13. NEEDLE ANATOMY CHANGES WITH INCREASING TREE AGE IN DOUGLAS FIR

    Science.gov (United States)

    Morphological differences between old growth and sapling (Pseudotsuga menziesii, (Mirb.) Franco) Douglas fir trees may extend to differences in needle anatomy. We used microscopy with image analysis to compare and quantify anatomical parameters in cross-sections of previous year...

  14. Balsam fir trees could disappear from W Va

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Newspaper article discussing the balsam fir tree could disappear from the forests of West Virginia within the next decade, unless humans intervene to help. The West...

  15. Researches on Nutrition in Cultivation of Chinese Fir

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A series ofresearches on the nutrition problems in the cultivation of Chinese fir seedlings and plantations, which are mainly focus on the problems of serious land degradation in Chinese fir plantations in contradiction with the rapid development of the plantations in China, were summarized. Twelve years was taken and more than 30 pieces of research papers were published for the researches, which refers to the problems of growth effect, physiological effect, vegetation variation, biomass accumulation, n...

  16. Application of a Hybrid Forest Growth Model to Evaluate Climate Change Impacts on Productivity, Nutrient Cycling and Mortality in a Montane Forest Ecosystem.

    Directory of Open Access Journals (Sweden)

    Brad Seely

    Full Text Available Climate change introduces considerable uncertainty in forest management planning and outcomes, potentially undermining efforts at achieving sustainable practices. Here, we describe the development and application of the FORECAST Climate model. Constructed using a hybrid simulation approach, the model includes an explicit representation of the effect of temperature and moisture availability on tree growth and survival, litter decomposition, and nutrient cycling. The model also includes a representation of the impact of increasing atmospheric CO2 on water use efficiency, but no direct CO2 fertilization effect. FORECAST Climate was evaluated for its ability to reproduce the effects of historical climate on Douglas-fir and lodgepole pine growth in a montane forest in southern British Columbia, Canada, as measured using tree ring analysis. The model was subsequently used to project the long-term impacts of alternative future climate change scenarios on forest productivity in young and established stands. There was a close association between predicted sapwood production and measured tree ring chronologies, providing confidence that model is able to predict the relative impact of annual climate variability on tree productivity. Simulations of future climate change suggest a modest increase in productivity in young stands of both species related to an increase in growing season length. In contrast, results showed a negative impact on stemwood biomass production (particularly in the case of lodgepole pine for established stands due to increased moisture stress mortality.

  17. Performance Analysis of LMS Adaptive FIR Filter and RLS Adaptive FIR Filter for Noise Cancellation

    Directory of Open Access Journals (Sweden)

    Jyotsna Yadav

    2013-06-01

    Full Text Available Interest in adaptive filters continues to grow as they begin to find practical real-time applications in areas such as channel equalization, echo cancellation, noise cancellation and many other adaptive signal processing applications. The key to successful adaptive signal processing understands the fundamental properties of adaptive algorithms such as LMS, RLS etc. Adaptive filter is used for the cancellation of the noise component which is overlap with undesired signal in the same frequency range. This paper presents design, implementation and performance comparison of adaptive FIR filter using LMS and RMS algorithms. MATLAB Simulink environment are used for simulations.

  18. Performance Analysis of LMS Adaptive FIR Filter and RLS Adaptive FIR Filter for Noise Cancellation

    Directory of Open Access Journals (Sweden)

    Jyotsna Yadav

    2013-07-01

    Full Text Available Interest in adaptive filters continues to grow as they begin to find practical real-time applications in areassuch as channel equalization, echo cancellation, noise cancellation and many other adaptive signalprocessing applications. The key to successful adaptive signal processing understands the fundamentalproperties of adaptive algorithms such as LMS, RLS etc. Adaptive filter is used for the cancellation of thenoise component which is overlap with undesired signal in the same frequency range. This paper presentsdesign, implementation and performance comparison of adaptive FIR filter using LMS and RMSalgorithms. MATLAB Simulink environment are used for simulations.

  19. Fir Decline and Mortality in the Southern Siberian Mountains

    Science.gov (United States)

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

    2016-01-01

    Increased dieback and mortality of dark needle conifer (DNC) stands (composed of fir (Abies sibirica),Siberian pine (Pinus sibirica) and spruce (Picea obovata))were documented in Russia during recent decades. Here we analyzed spatial and temporal patterns of fir decline and mortality in the southern Siberian Mountains based on satellite, in situ and dendrochronological data. The studied stands are located within the boundary between DNC taiga to the north and forest-steppe to the south. Fir decline and mortality were observed to originate where topographic features contributed to maximal water-stress risk, i.e., steep (1825),convex, south-facing slopes with a shallow well-drained root zone. Fir regeneration survived droughts and increased stem radial growth, while upper canopy trees died. Tree ring width(TRW) growth negatively correlated with vapor pressure deficit (VPD), drought index and occurrence of late frosts, and positively with soil water content. Previous year growth conditions (i.e., drought index, VPD, soil water anomalies)have a high impact on current TRW (r 0.600.74). Fir mortality was induced by increased water stress and severe droughts (as a primary factor) in synergy with bark-beetles and fungi attacks (as secondary factors). Dendrochronology data indicated that fir mortality is a periodic process. In a future climate with increased aridity and drought frequency, fir (and Siberian pine) may disappear from portions of its current range (primarily within the boundary with the forest steppe)and is likely to be replaced by drought-tolerant species such as Pinus sylvestris and Larix sibirica.

  20. FIR line emission from high redshift galaxies

    CERN Document Server

    Vallini, Livia; Ferrara, Andrea; Baek, Sunghye

    2013-01-01

    By combining high resolution, radiative transfer cosmological simulations of z~6 galaxies with a sub-grid multi-phase model of their interstellar medium we derive the expected intensity of several far infrared (FIR) emission lines ([C II] 158 micron, [O I] 63 micron, and [N II] 122 micron) for different values of the gas metallicity, Z. For Z = Z_sun the [C II] spectrum is very complex due to the presence of several emitting clumps of individual size < 3 kpc; the peak is displaced from the galaxy center by ~100 km/s. While the [O I] spectrum is also similarly displaced, the [N II] line comes predominantly from the central ionized regions of the galaxy. When integrated over ~500 km/s, the [C II] line flux is 185 mJy km/s; 95% of such flux originates from the cold (T~250 K) H I phase, and only 5% from the warm (T~5000 K) neutral medium. The [O I] and [N II] fluxes are ~6 and ~90 times lower than the [C II] one, respectively. By comparing our results with observations of Himiko, the most extended and luminous...

  1. Photo series for quantifying forest fuels in Mexico: montane subtropical forests of the Sierra Madre del Sur and temperate forests and montane shrubland of the northern Sierra Madre Oriental

    Science.gov (United States)

    Jorge E. Morfin-Rios; Ernesto Alvarado-Celestino; Enrique J. Jardel-Pelaez; Robert E. Vihnanek; David K. Wright; Jose M. Michel-Fuentes; Clinton S. Wright; Roger D. Ottmar; David V. Sandberg; Andres Najera-Diaz

    2008-01-01

    Single wide-angle and stereo photographs display a range of forest ecosystems conditions and fuel loadings in montane subtropical forests of the Sierra Madre del Sur and temperate forests and montane shrubland of the northern Sierra Madre Oriental of Mexico. Each group of photographs includes inventory information summarizing overstory vegetation composition and...

  2. High Speed Reconfigurable FIR Filter using Russian Peasant Multiplier with Sklansky Adder

    Directory of Open Access Journals (Sweden)

    K. Gunasekaran

    2014-12-01

    Full Text Available The Reconfigurable FIR filters are commonly used digital filters which find its major applications in digital signal processing and multi-standard wireless communications. The Direct form of FIR filter used in DSP application which consumes more area and power. To overcome this problem Multiplier Control Signal Decision (MCSD window schemes is incorporated into direct form FIR filter in order to dynamically change the filter order. Conventional reconfigurable FIR filter is designed using Russian Peasant Multiplier which consumes more area and delay due to poor performance of adder used in multiplication unit. In this study, modified reconfigurable FIR filter is designed to further reduce the area, power and time. In proposed Reconfigurable FIR filter, a Wallace adder is replaced by carry select adder with sklansky adder in Russian Peasant Multiplication technique. Hence, modified Reconfigurable FIR filter with carry select adder with sklansky adder consumes less area, delay and power than the conventional Reconfigurable FIR architecture with Russian Peasant Multiplication technique.

  3. Genetic structure of colline and montane populations of an endangered plant species.

    Science.gov (United States)

    Maurice, Tiphaine; Matthies, Diethart; Muller, Serge; Colling, Guy

    2016-08-12

    Due to land-use intensification, lowland and colline populations of many plants of nutrient-poor grasslands have been strongly fragmented in the last decades, with potentially negative consequences for their genetic diversity and persistence. Populations in mountains might represent a genetic reservoir for grassland plants, because they have been less affected by land-use changes. We studied the genetic structure and diversity of colline and montane Vosges populations of the threatened perennial plant Arnica montana in western central Europe using AFLP markers. Our results indicate that in contrast to our expectation even strongly fragmented colline populations of A. montana have conserved a considerable amount of genetic diversity. However, mean seed mass increased with the proportion of polymorphic loci, suggesting inbreeding effects in low diversity populations. At a similar small geographical scale there was a clear IBD pattern for the montane Vosges but not for the colline populations. However, there was a strong IBD-pattern for the colline populations at a large geographical scale suggesting that this pattern is a legacy of historical gene flow, as most of the colline populations are today strongly isolated from each other. Genetic differentiation between colline and montane Vosges populations was strong. Moreover, results of a genome scan study indicated differences in loci under selection, suggesting that plants from montane Vosges populations might be maladapted to conditions at colline sites. Our results suggest caution in using material from montane populations of rare plants for the reinforcement of small genetically depauperate lowland populations.

  4. Genetic structure of colline and montane populations of an endangered plant species

    Science.gov (United States)

    Maurice, Tiphaine; Matthies, Diethart; Muller, Serge; Colling, Guy

    2016-01-01

    Due to land-use intensification, lowland and colline populations of many plants of nutrient-poor grasslands have been strongly fragmented in the last decades, with potentially negative consequences for their genetic diversity and persistence. Populations in mountains might represent a genetic reservoir for grassland plants, because they have been less affected by land-use changes. We studied the genetic structure and diversity of colline and montane Vosges populations of the threatened perennial plant Arnica montana in western central Europe using AFLP markers. Our results indicate that in contrast to our expectation even strongly fragmented colline populations of A. montana have conserved a considerable amount of genetic diversity. However, mean seed mass increased with the proportion of polymorphic loci, suggesting inbreeding effects in low diversity populations. At a similar small geographical scale, there was a clear IBD pattern for the montane Vosges but not for the colline populations. However, there was a strong IBD-pattern for the colline populations at a large geographical scale suggesting that this pattern is a legacy of historical gene flow, as most of the colline populations are today strongly isolated from each other. Genetic differentiation between colline and montane Vosges populations was strong. Moreover, results of a genome scan study indicated differences in loci under selection, suggesting that plants from montane Vosges populations might be maladapted to conditions at colline sites. Our results suggest caution in using material from montane populations of rare plants for the reinforcement of small genetically depauperate lowland populations. PMID:27519913

  5. Chimpanzee seed dispersal in a montane forest fragment in Rwanda.

    Science.gov (United States)

    Chancellor, Rebecca L; Rundus, Aaron S; Nyandwi, Sylvain

    2017-03-01

    Primate seed dispersal plays an important role in forest regeneration. It may be particularly important to anthropogenically disturbed habitats such as forest fragments. However, few studies have examined primate seed dispersal in these types of environments. Chimpanzees (Pan troglodytes) are frugivorous and large-bodied, and are therefore able to disperse both large and small seeds, making them an important seed dispersal species. We examined chimpanzee seed dispersal in Gishwati forest, a 14 km(2) montane rainforest fragment in Rwanda. We systematically collected ≤24-hr-old fecal samples and counted the number of seeds of each fruit species. We also recorded observations of seeds found in wadges. We found that chimpanzees dispersed at least 18 fruit species in 14 families in their feces. Ninety-five percent of feces had seeds, the most common of which were Ficus spp., Myrianthus holstii, and Maesa lanceolata. We estimated that the Gishwati chimpanzee community with a density of 1.7 individuals per km(2) dispersed an average of 592 (>2 mm) seeds km(-2)  day(-1) . We also found that chimpanzees dispersed the seeds of at least two fruit species, Ficus spp. and Chrysophyllum gorungosanum, in their wadges. In addition, 17% of the tree species recorded in our vegetation plots were chimpanzee-dispersed. This study emphasizes the importance of chimpanzees as large seed dispersers in regenerating forest fragments.

  6. Effects of tropical montane forest disturbance on epiphytic macrolichens.

    Science.gov (United States)

    Benítez, Angel; Prieto, María; González, Yadira; Aragón, Gregorio

    2012-12-15

    The high diversity of epiphytes typical of undisturbed montane tropical forests has been negatively affected by continuous deforestation and forest conversion to secondary vegetation. Macrolichens are an important component of these epiphytes. Because their physiology is strongly coupled to humidity and solar radiation, we hypothesized that microclimatic changes derived from forest clearing and logging can affect the diversity of these poikilohydric organisms. In southern Ecuador, we examined three types of forests according to a disturbance gradient (primary forests, secondary forests, and monospecific forests of Alnus acuminata) for the presence/absence and coverage of epiphytic macrolichens that we identified on 240 trees. We found that total richness tended to decrease when the range of the disturbance increased. The impoverishment was particularly drastic for "shade-adapted lichens", while the richness of "heliophytic lichens" increased in the drier conditions of secondary growth. Epiphytic composition also differed significantly among the three types of forests, and the similarity decreased when the range of the disturbance was greater. We concluded that a span of 40 years of recovery by secondary vegetation was not enough to regenerate the diversity of epiphytic macrolichens that was lost due to forest disturbances. Copyright © 2012 Elsevier B.V. All rights reserved.

  7. A small animal model study of perlite and fir bark dust on guinea pig lungs.

    Science.gov (United States)

    McMichael, R F; DiPalma, J R; Blumenstein, R; Amenta, P S; Freedman, A P; Barbieri, E J

    1983-05-01

    Fir bark (Abies) and perlite (noncrystalline silicate) dusts have been reported to cause pulmonary disease in humans. Guinea pigs were exposed to either fir bark or perlite dust in a special chamber. Severe pathologic changes occurred in the lungs, consisting of lymphoid aggregated and a perivascular inflammatory response. Both dusts caused similar changes although one was vegetable (fir bark) and the other mineral (perlite). Fir bark and perlite dust appeared to be more than just nuisance dusts.

  8. Design of Low Pass Digital FIR Filter Using Cuckoo Search Algorithm

    OpenAIRE

    Taranjit Singh; Harvinder Singh Josan

    2014-01-01

    This paper presents a novel approach of designing linear phase FIR low pass filter using cuckoo Search Algorithm (CSA). FIR filter design is a multi-modal optimization problem. The conventional optimization techniques are not efficient for digital filter design. An iterative method is introduced to find the best solution of FIR filter design problem.Flat passband and high stopband attenuation are the major characteristics required in FIR filter design. To achieve these charact...

  9. Scientific Opinion on the re-evaluation of montan acid esters (E 912 as a food additive

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS

    2013-06-01

    Full Text Available Following a request from the European Commission, the EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS was asked to deliver a scientific opinion re-evaluating the safety of montan acid esters (E 912 when used as a food additive. Montan acids are extracted from oxidised montan wax and esterified with ethylene glycol, 1,3-butanediol or triols, to form montan acid esters. Montan acid esters are authorised only for the surface treatment of fresh fruits. No data, specifically for montan acid esters, on toxicokinetics and reproductive and developmental toxicity were available. The available data on short-term and subchronic toxicity, genotoxicity and chronic toxicity and carcinogenicity were limited. Important deficiencies in the available studies on chronic toxicity and carcinogenicity were noticed. The data requested in the 1990s (i.e. chromosomal aberration in vitro, reproduction and teratogenicity studies, material characteristics, impurities, presence of PAHs were not submitted. Furthermore no data were submitted following an EFSA public call for data in 2012. The Panel identified some summary data in the European Chemicals Agency database (ECHA on registered substances that might have been relevant for the assessment of montan acid esters but the original study reports were not made available to EFSA. Based on these limitations in the toxicological database the Panel concluded that montan acid esters as a food additive could not be evaluated.

  10. Investigation of Carbohydrate Compositions for Poplar Ⅰ-214 and Chinese Fir

    Institute of Scientific and Technical Information of China (English)

    HUANG Luohua; QIN Tefu; MAGARA Kengo

    2006-01-01

    The carbohydrate compositions of poplar Ⅰ-214 and Chinese fir were investigated by the methods of hydrolysis and HPLC.The result showed that the contents of glucose,xylose and arabinose in poplar Ⅰ-214 are higher than those in Chinese fir,while contents of rhamnose and mannose in poplar Ⅰ-214 are lower than those in Chinese fir.

  11. Altitudinal gradients of bryophyte diversity and community assemblage in southern Appalachian spruce-fir forests

    Science.gov (United States)

    Sarah E. Stehn; Christopher R. Webster; Janice M. Glime; Michael A. Jenkins

    2010-01-01

    Ground-layer plant communities in spruce-fir forests of the southern Appalachians have likely undergone significant change since the widespread death of canopy Fraser fir (Abies fraseri) caused by the exotic balsam woolly adelgid (Adelges piceae). Bryophytes comprise an important part of the ground-layer flora in the spruce-fir...

  12. FPGA-Based Efficient Programmable Polyphase FIR Filter

    Institute of Scientific and Technical Information of China (English)

    CHEN He; XIONG Cheng-huan; ZHONG Shu-nan; WANG Hua

    2005-01-01

    The modelling, design and implementation of a high-speed programmable polyphase finite impulse response (FIR) filter with field programmable gate array (FPGA) technology are described. This FIR filter can run automatically according to the programmable configuration word including symmetry/asymmetry, odd/even taps, from 32 taps up to 256 taps. The filter with 12 bit signal and 12 bit coefficient word-length has been realized on a Xilinx VirtexⅡ-v1500 device and operates at the maximum sampling frequency of 160 MHz.

  13. Macroscopic Thermal Energy Balance on Montane Valley Aquifers and Groundwater Recharge Source Identification

    Science.gov (United States)

    Trask, J. C.; Fogg, G. E.

    2010-12-01

    Several recent publications have highlighted the need to improve definition of groundwater flow patterns in montane regions, presenting case studies with several field investigative approaches. Determination of the depth of upland bedrock groundwater circulation and identification of valley aquifer recharge sources in montane areas is needed for improved characterization of montane groundwater flow patterns and for aquifer source protection planning. In most upland bedrock regions, wells and boreholes are scarce, adding to the challenges inherent to investigating groundwater flow in fractured rock systems. Approaches using natural environmental tracers have previously been shown to be effective in quantifying subsurface recharge into valley aquifers from groundwater flow within adjoining mountain-front and mountain-block areas. Thermal tracing of montane groundwater flow is easy and inexpensive relative to other environmental tracer and geophysical techniques, and can complement other approaches (e.g. Manning and Solomon, 2005). We present a heat flow tracer approach to identification of montane valley aquifer recharge sources. A novel application of a macroscopic thermal energy balance is introduced and used in recharge source analysis for two mountain-front bounding basin-fill aquifers located in the Sierra Nevada, USA. We show that robust upper and lower bounds on total heat flow and sources of recharge into montane valley aquifers may be determined without numerical modeling by using a macroscopic thermal energy balance. Several factors tend to enhance focusing of geothermal conductive heat flow from depth toward montane valley margins. Analytic bracketing techniques, applicable to domains with irregular boundary geometry and non-uniform thermal boundary conditions, are used together with thermal data to obtain quantitative bounds on conductive heat flow across aquifer domain boundaries. Thermal data required include: (i) a rough estimate of regional geothermal

  14. Drivers of methane uptake by montane forest soils in the Peruvian Andes

    Science.gov (United States)

    Jones, Sam; Diem, Torsten; Huaraca Quispe, Lidia; Cahuana, Adan; Meir, Patrick; Teh, Yit

    2016-04-01

    The exchange of methane between the soils of humid tropical forests and the atmosphere is relatively poorly documented. This is particularly true of montane settings where variations between uptake and emission of atmospheric methane have been observed. Whilst most of these ecosystems appear to function as net sinks for atmospheric methane, some act as considerable sources. In regions like the Andes, humid montane forests are extensive and a better understanding of the magnitude and controls on soil-atmosphere methane exchange is required. We report methane fluxes from upper montane cloud forest (2811 - 2962 m asl), lower montane cloud forest (1532 - 1786 m asl), and premontane forest (1070 - 1088 m asl) soils in south-eastern Peru. Between 1000 and 3000 m asl, mean annual air temperature and total annual precipitation decrease from 24 ° C and 5000 mm to 12 ° C and 1700 mm. The study region experiences a pronounced wet season between October and April. Monthly measurements of soil-atmosphere gas exchange, soil moisture, soil temperature, soil oxygen concentration, available ammonium and available nitrate were made from February 2011 in the upper and lower montane cloud forests and July 2011 in the premontane forest to June 2013. These soils acted as sinks for atmospheric methane with mean net fluxes for wet and dry season, respectively, of -2.1 (0.2) and -1.5 (0.1) mg CH4 m-2 d-1 in the upper montane forest; -1.5 (0.2) and -1.4 (0.1) mg CH4 m-2 d-1in the lower montane forest; and -0.3 (0.2) and -0.2 (0.2) mg CH4 m-2 d-1 in the premontane forest. Spatial variations among forest types were related to available nitrate and water-filled pore space suggesting that nitrate inhibition of oxidation or constraints on the diffusional supply of methane to methanotrophic communities may be important controls on methane cycling in these soils. Seasonality in methane exchange, with weaker uptake related to increased water-filled pore space and soil temperature during the wet

  15. The ISS Fluids Integrated Rack (FIR): a Summary of Capabilities

    Science.gov (United States)

    Gati, F.; Hill, M. E.

    2002-01-01

    The Fluids Integrated Rack (FIR) is a modular, multi-user scientific research facility that will fly in the U.S. laboratory module, Destiny, of the International Space Station (ISS). The FIR will be one of the two racks that will make up the Fluids and Combustion Facility (FCF) - the other being the Combustion Integrated Rack (CIR). The ISS will provide the FCF with the necessary resources, such as power and cooling. While the ISS crew will be available for experiment operations, their time will be limited. The FCF is, therefore, being designed for autonomous operations and remote control operations. Control of the FCF will be primarily through the Telescience Support Center (TSC) at the Glenn Research Center. The FCF is being designed to accommodate a wide range of combustion and fluids physics experiments within the ISS resources and constraints. The primary mission of the FIR, however, is to accommodate experiments from four major fluids physics disciplines: Complex Fluids; Multiphase Flow and Heat Transfer; Interfacial Phenomena; and Dynamics and Stability. The design of the FIR is flexible enough to accommodate experiments from other science disciplines such as Biotechnology. The FIR flexibility is a result of the large volume dedicated for experimental hardware, easily re-configurable diagnostics that allow for unique experiment configurations, and it's customizable software. The FIR will utilize six major subsystems to accommodate this broad scope of fluids physics experiments. The major subsystems are: structural, environmental, electrical, gaseous, command and data management, and imagers and illumination. Within the rack, the FIR's structural subsystem provides an optics bench type mechanical interface for the precise mounting of experimental hardware; including optical components. The back of the bench is populated with FIR avionics packages and light sources. The interior of the rack is isolated from the cabin through two rack doors that are hinged near

  16. Performance Evaluation of FIR Filter After Implementation on Different FPGA and SOC and Its Utilization in Communication and Network

    DEFF Research Database (Denmark)

    Pandey, Bishwajeet; Das, Bhagwan; Kaur, Amanpreet

    2017-01-01

    There are many areas of communication and network, which have open scope to use FIR filter. Therefore, energy efficient FIR filter will increase lifetime of network and FIR filter with less delay and latency will increase performance of network. In this work, we are going to design an FIR filter ...

  17. Factors influencing stream baseflow transit times in tropical montane watersheds

    Science.gov (United States)

    Muñoz-Villers, Lyssette E.; Geissert, Daniel R.; Holwerda, Friso; McDonnell, Jeffrey J.

    2016-04-01

    Stream water mean transit time (MTT) is a fundamental hydrologic parameter that integrates the distribution of sources, flow paths, and storages present in catchments. However, in the tropics little MTT work has been carried out, despite its usefulness for providing important information on watershed functioning at different spatial scales in (largely) ungauged basins. In particular, very few studies have quantified stream MTTs or have related these to catchment characteristics in tropical montane regions. Here we examined topographic, land use/cover and soil hydraulic controls on baseflow transit times for nested catchments (0.1-34 km2) within a humid mountainous region, underlain by volcanic soil (Andisols) in central Veracruz (eastern Mexico). We used a 2-year record of bi-weekly isotopic composition of precipitation and stream baseflow data to estimate MTT. Land use/cover and topographic parameters (catchment area and form, drainage density, slope gradient and length) were derived from geographic information system (GIS) analysis. Soil water retention characteristics, and depth and permeability of the soil-bedrock interface were obtained from intensive field measurements and laboratory analysis. Results showed that baseflow MTTs ranged between 1.2 and 2.7 years across the 12 study catchments. Overall, MTTs across scales were mainly controlled by catchment slope and the permeability observed at the soil-bedrock interface. In association with topography, catchment form and the depth to the soil-bedrock interface were also identified as important features influencing baseflow MTTs. The greatest differences in MTTs were found both within groups of small (0.1-1.5 km2) and large (14-34 km2) catchments. Interestingly, the longest stream MTTs were found in the headwater cloud forest catchments.

  18. Provenance variability in nursery growth of subalpine fir

    Science.gov (United States)

    Charlie Cartwright; Cheng Ying

    2011-01-01

    Subalpine fir (Abies lasiocarpa [Hook] Nutt.) is a wide-ranging, high-elevation species in the interior of British Columbia. It is commonly harvested for lumber, but replanting of it is limited. Some reticence is based upon wood quality and rate of growth, but there are also seed and nursery culturing difficulties. This study investigated seedling growth traits of 111...

  19. Animal damage to young spruce and fir in Maine

    Science.gov (United States)

    Barton M. Blum

    1977-01-01

    The loss of terminal buds on small balsam fir (Abies balsamea (L.) Mill.) and spruce (Picea spp.) trees because of nipping by mammals or birds has increased on the Penobscot Experimental Forest in recent years. The cut stem is smooth and slightly angled; there is no sign of tearing. Unnipped trees grew about 13 percent more than...

  20. The New England Spruce-Fir Seed Orchard Program

    Science.gov (United States)

    Carter B. Gibbs; James B. Carlaw

    1973-01-01

    I once heard it said that if you want to know how something was organized, ask a man who had nothing to do with it. I suspect this may be one of the reasons I was asked to collaborate on this report of the development of the New England Spruce-Fir Seed Orchard Program.

  1. On mycorrhiza development of spruces and firs in damaged stands

    Energy Technology Data Exchange (ETDEWEB)

    Ritter, T.; Weber, G.; Kottke, I.; Oberwinkler, F.

    1989-02-01

    The authors studied the very fine roots of sick spruces and firs and established the following: 1. a surprising stability of mycorrhiza development, 2. differences in the dynamism of development and 3. modifications in the composition of the accompanying microfungi. The results suggest connections in the chain of causes of forest disease which have received little attention so far.

  2. The FIR/submm window on galaxy formation

    CERN Document Server

    Guiderdoni, B; Devriendt, J E G; Hivon, E; Puget, J L

    1999-01-01

    Our view on the deep universe has been so far biased towards optically bright galaxies. Now, the measurement of the Cosmic Infrared Background in FIRAS and DIRBE residuals, and the observations of FIR/submm sources by the ISOPHOT and SCUBA instruments begin unveiling the ``optically dark side'' of galaxy formation. Though the origin of dust heating is still unsolved, it appears very likely that a large fraction of the FIR/submm emission is due to heavily-extinguished star formation. Consequently, the level of the CIRB implies that about 2/3 of galaxy/star formation in the universe is hidden by dust shrouds. In this review, we introduce a new modeling of galaxy formation and evolution that provides us with specific predictions in FIR/submm wavebands. These predictions are compared with the current status of the observations. Finally, the capabilities of current and forthcoming instruments for all-sky and deep surveys of FIR/submm sources are briefly described.

  3. Critical Path Reduction of Distributed Arithmetic Based FIR Filter

    Directory of Open Access Journals (Sweden)

    Sunita Badave

    2016-03-01

    Full Text Available Operating speed, which is reciprocal of critical path computation time, is one of the prominent design matrices of finite impulse response (FIR filters. It is largely affected by both, system architecture as well as technique used to design arithmetic modules. A large computation time of multipliers in conventionally designed multipliers, limits the speed of system architecture. Distributed arithmetic is one of the techniques, used to provide multiplier-free multiplication in the implementation of FIR filter. However suffers from a sever limitation of exponential growth of look up table (LUT with order of filter. An improved distributed arithmetic technique is addressed here to design for system architecture of FIR filter. In proposed technique, a single large LUT of conventional DA is replaced by number of smaller indexed LUT pages to restrict exponential growth and to reduce system access time. It also eliminates the use of adders. Selection module selects the desired value from desired page, which leads to reduce computational time of critical path. Trade off between access times of LUT pages and selection module helps to achieve minimum critical path so as to maximize the operating speed. Implementations are targeted to Xilinx ISE, Virtex IV devices. FIR filter with 8 bit data width of input sample results are presented here. It is observed that, proposed design perform significantly faster as compared to the conventional DA and existing DA based designs.

  4. Nitrogen Availability in Fresh and Aged Douglas Fir Bark

    Science.gov (United States)

    The objective of this study was to determine if there are growth differences in geranium (Pelargonium ×hortorum Bailey 'Maverick Red') produced in either fresh or aged Douglas fir [Pseudotsuga menziesii (Mirbel) Franco] bark (DFB). A second objective was to document nitrogen immobilization and deco...

  5. The biology of arboreal rodents in Douglas-fir forests.

    Science.gov (United States)

    Andrew B. Carey

    1991-01-01

    Arboreal rodents in Douglas-fir forests west of the Cascade crest in Oregon and Washington include (listed in decreasing order of dependence on trees) red tree vole (Phenacomys longicaucfus), northern flying squirrel (Glaucomys sabrinus), Douglas' squirrel (Tamiasciurus douglasii), dusky-footed woodrat...

  6. Biology of bats in Douglas-fir forests.

    Science.gov (United States)

    Robin E. Christy; Stephen D. West

    1993-01-01

    Twelve species of bats occur in Douglas-fir forests of the Pacific Northwest, of which nine are known to roost in tree cavities, bark crevices, or foliage, and several are closely associated with old-growth forests. Thus bat populations may be detrimentally affected by forest management practices involving the removal of large, old trees and snags. We review the life...

  7. Influences of previous wildfires on change, resistance, and resilience to reburning in a montane southwestern landscape

    Science.gov (United States)

    Jonathan D. Coop; Lisa Holsinger; Sarah McClernan; Sean A. Parks

    2015-01-01

    Land use legacies and climate have altered fire regimes across montane forests of much of the southwestern US (Allen and others 2002), and several recent wildfires have been extremely large and severe (Dennison and others 2014). Large openings resulting from high-severity fire in former ponderosa pine (Pinus ponderosa) and mixed conifer forests may be persistent given...

  8. A new species of Gulella (Pulmonata: Streptaxidae) from montane forest in the Ndoto Mountains, Kenya

    NARCIS (Netherlands)

    Rowson, B.; Seddon, M.B.; Tattersfield, P.

    2009-01-01

    Gulella mkuu spec. nov. is described from montane forest in the isolated Ndoto Mountains of northern Kenya. Although exceptionally large for the genus, shell, genitalia and radula features suggest it is more closely related to the "G. sellae-ugandensis" complex than to other very large East African

  9. Modification of global precipitation data for enhanced hydrologic modeling of tropical montane watersheds

    Science.gov (United States)

    Strauch, Michael; Kumar, Rohini; Eisner, Stephanie; Mulligan, Mark; Reinhardt, Julia; Samaniego, Luis; Santini, William; Vetter, Tobias; Friesen, Jan

    2016-04-01

    Global gridded precipitation is an essential driving input for hydrologic models to simulate runoff dynamics in large river basins. However, the data often fail to adequately represent precipitation variability in mountainous regions due to orographic effects and sparse and highly uncertain gauge data. Water balance simulations in tropical montane regions covered by cloud forests are especially challenging because of the additional water input from cloud water interception. The ISI-MIP2 hydrologic model ensemble encountered these problems for Andean sub-basins of the Upper Amazon Basin, where all models significantly underestimated observed runoff. In this paper, we propose simple yet plausible ways to adjust global precipitation data provided by WFDEI, the WATCH Forcing Data methodology applied to ERA-Interim reanalysis, for tropical montane watersheds. The modifications were based on plausible reasoning and freely available tropics-wide data: (i) a high-resolution climatology of the Tropical Rainfall Measuring Mission (TRMM) and (ii) the percentage of tropical montane cloud forest cover. Using the modified precipitation data, runoff predictions significantly improved for all hydrologic models considered. The precipitation adjustment methods presented here have the potential to enhance other global precipitation products for hydrologic model applications in the Upper Amazon Basin as well as in other tropical montane watersheds.

  10. Fagus dominance in Chinese montane forests: natural regeneration of Fagus lucida and Fagus hayatae var. pashanica.

    NARCIS (Netherlands)

    Cao, K.F.

    1995-01-01

    Fagus species are important components of certain mesic temperate forests in the Northern Hemisphere. Of eleven Fagus species distinguished, five are found in China. Chinese beeches are restricted to the mountains of southern China. In the montane zones of the northern subtropics beeches (Fagus engl

  11. Successional dynamics and restoration implications of a montane coniferous forest in the central Appalachians, USA

    Science.gov (United States)

    Thomas M. Schuler; Rachel J. Collins

    2002-01-01

    Central Appalachian montane red spruce (Picea rubens Sarg.) communities have been greatly reduced in extent and functional quality over the past century. This community decline has put several plant and animal species, such as the endangered Virginia northern flying squirrel (Glaucomys sabrinus fuscus Shaw), at risk from habitat...

  12. Elevational Distribution of Adult Trees and Seedlings in a Tropical Montane Transect, Southwest China

    Directory of Open Access Journals (Sweden)

    Xiaoyang Song

    2016-08-01

    Full Text Available Montane habitats are characterized by high variation of environmental factors within small geographic ranges, which offers opportunities to explore how forest assemblages respond to changes in environmental conditions. Understanding the distributional transition of adult trees and seedlings will provide insight into the fate of forest biodiversity in response to future climate change. We investigated the elevational distribution of 156 species of adult trees and 152 species of seedlings in a tropical montane forest in Xishuangbanna, southwest China. Adult trees and seedlings were surveyed within 5 replicate plots established at each of 4 elevational bands (800, 1000, 1200, and 1400 m above sea level. We found that species richness of both adult trees and seedlings changed with elevation, showing a notable decline in diversity values from 1000 to 1200 m. Tree species composition also demonstrated distinct differences between 1000 and 1200 m, marking the division between tropical seasonal rain forest (800 and 1000 m and tropical montane evergreen broad-leaved forest (1200 and 1400 m. The results suggested that soil moisture and temperature regimes were associated with elevational distribution of tree species in this region. We also observed that seedlings from certain species found at high elevations were also distributed in low-elevation zones, but no seedlings of species from low elevations were distributed in high-elevation zones. The increase in temperature and droughts predicted for this region may result in the contraction of tropical seasonal rain forest at lower elevations and a downhill shift of higher tropical montane tree species.

  13. Green economy: un'occasione per le aree montane

    Directory of Open Access Journals (Sweden)

    Maria Sapone

    2013-06-01

    di rivitalizzare le aree montane. Il presente contributo rappresenta un avanzamento di studio sui temi che hanno interessato la costruzione di una rete di ecovillaggi approfondendo problematiche relative all'economia locale, al paesaggio e, più in generale, alla sostenibilità ambientale. Normal 0 14 false false false IT ZH-TW X-NONE

  14. Drivers of atmospheric methane uptake by montane forest soils in the southern Peruvian Andes

    Science.gov (United States)

    Jones, Sam P.; Diem, Torsten; Huaraca Quispe, Lidia P.; Cahuana, Adan J.; Reay, Dave S.; Meir, Patrick; Arn Teh, Yit

    2016-07-01

    The soils of tropical montane forests can act as sources or sinks of atmospheric methane (CH4). Understanding this activity is important in regional atmospheric CH4 budgets given that these ecosystems account for substantial portions of the landscape in mountainous areas like the Andes. We investigated the drivers of net CH4 fluxes from premontane, lower and upper montane forests, experiencing a seasonal climate, in south-eastern Peru. Between February 2011 and June 2013, these soils all functioned as net sinks for atmospheric CH4. Mean (standard error) net CH4 fluxes for the dry and wet season were -1.6 (0.1) and -1.1 (0.1) mg CH4-C m-2 d-1 in the upper montane forest, -1.1 (0.1) and -1.0 (0.1) mg CH4-C m-2 d-1 in the lower montane forest, and -0.2 (0.1) and -0.1 (0.1) mg CH4-C m-2 d-1 in the premontane forest. Seasonality in CH4 exchange varied among forest types with increased dry season CH4 uptake only apparent in the upper montane forest. Variation across these forests was best explained by available nitrate and water-filled pore space indicating that nitrate inhibition of oxidation or diffusional constraints imposed by changes in water-filled pore space on methanotrophic communities may represent important controls on soil-atmosphere CH4 exchange. Net CH4 flux was inversely related to elevation; a pattern that differs to that observed in Ecuador, the only other extant study site of soil-atmosphere CH4 exchange in the tropical Andes. This may result from differences in rainfall patterns between the regions, suggesting that attention should be paid to the role of rainfall and soil moisture dynamics in modulating CH4 uptake by the organic-rich soils typical of high-elevation tropical forests.

  15. Evolutionary history and population genetics of fraser fir and intermediate fir, southern Appalachian endemic conifers imperiled by an exotic pest and climate change

    Science.gov (United States)

    Kevin M. Potter; John Frampton; Sedley Josserand; C. Dana. Nelson

    2010-01-01

    Two Abies (true fir) taxa are endemic to high elevations of the Appalachian Mountains, where both are restricted to small populations and are imperiled by the same exotic insect. Fraser fir (Abies fraseri) exists in a handful of island-like populations on mountain ridges in the southern Appalachians of North Carolina, Tennessee and...

  16. Abies religiosa habitat prediction in climatic change scenarios and implications for monarch butterfly conservation in Mexico

    Science.gov (United States)

    Cuauhtemoc Saenz-Romero; Gerald E. Rehfeldt; Pierre Duval; Roberto A. Lindig-Cisneros

    2012-01-01

    Abies religiosa (HBK) Schl. & Cham. (oyamel fir) is distributed in conifer-dominated mountain forests at high altitudes along the Trans-Mexican Volcanic Belt. This fir is the preferred host for overwintering monarch butterfly (Danaus plexippus) migratory populations which habitually congregate within a few stands now located inside a Monarch Butterfly Biosphere...

  17. Design of Low Pass Digital FIR Filter Using Cuckoo Search Algorithm

    Directory of Open Access Journals (Sweden)

    Taranjit Singh

    2014-08-01

    Full Text Available This paper presents a novel approach of designing linear phase FIR low pass filter using cuckoo Search Algorithm (CSA. FIR filter design is a multi-modal optimization problem. The conventional optimization techniques are not efficient for digital filter design. An iterative method is introduced to find the best solution of FIR filter design problem.Flat passband and high stopband attenuation are the major characteristics required in FIR filter design. To achieve these characteristics, a Cuckoo Search algorithm (CSA is proposed in this paper. CSA have been used here for the design of linear phase finite impulse response (FIR filters. Results are presented in this paper that seems to be promising tool for FIR filter design

  18. Noniterative Design of 2-Channel FIR Orthogonal Filters

    Directory of Open Access Journals (Sweden)

    Jiménez M Elena Domínguez

    2007-01-01

    Full Text Available This paper addresses the problem of obtaining an explicit expression of all real FIR paraunitary filters. In this work, we present a general parameterization of 2-channel FIR orthogonal filters. Unlike other approaches which make use of a lattice structure, we show that our technique designs any orthogonal filter directly, with no need of iteration procedures. Moreover, in order to design an -tap 2-channel paraunitary filterbank, it suffices to choose independent parameters, and introduce them in a simple expression which provides the filter coefficients directly. Some examples illustrate how this new approach can be used for designing filters with certain desired properties. Further conditions can be eventually imposed on the parameters so as to design filters for specific applications.

  19. Cost Analysis of Different Digital Fir Filter Design Methods

    Directory of Open Access Journals (Sweden)

    Amninder Singh,

    2014-05-01

    Full Text Available FIR digital filters are widely used in the communication world. The implementation cost of filter circuit is counted by the number of multipliers & adders used, that decides the chip area. In this paper, design techniques of low pass FIR filter using the different windows are presented. The simulation is done in MATLAB. It is shown that filter designed using Hamming and Blackman windows are better than rest of the windows used. Out of two, Hamming window is better as its transition width is narrow, 0.019 than Blackman, 0.034. Further the performance analysis of Kaiser Window, Equiripple and Minimum phase filters was obtained, for same 0.04 transition width. There is a disparity in implementation cost & area. The minimum phase filter can be implemented with lesser number of filter coefficients with tolerable pass-band, stop-band ripples specifications.

  20. Cyclotron Resonance Gain for FIR and THz Radiation in Graphene

    CERN Document Server

    Cole, Nightvid

    2016-01-01

    A cyclotron resonance maser source using low-effective-mass conduction electrons in graphene, if successful, would allow for generation of Far Infrared (FIR) and Terahertz (THz) radiation without requiring magnetic fields running into the tens of Tesla. In order to investigate this possibility, we consider a device in which electrons are effectively injected via pumping from the valence band to the conduction band using an infrared (IR) laser source, subsequently gyrate in a magnetic field applied perpendicular to the plane of the graphene, and give rise to gain for a FIR/THz wave crossing the plane of the graphene. A set of integral expressions is derived by assuming that the non-radiative energy loss processes of the electrons can be adequately represented by a damping force proportional and antiparallel to their momentum. Minimal gain may occur at very short electron damping times of hundreds of femtoseconds.

  1. Degrading Precision Arithmetics for Low-power FIR Implementation

    DEFF Research Database (Denmark)

    Albicocco, Pietro; Cardarilli, Gian Carlo; Nannarelli, Alberto

    2011-01-01

    In this paper a review of different techniques used to implement highly optimized DSP systems is presented. The case of study is the implementation of parallel FIR filters aimed to applications characterized by high speed and high selectivity in frequency where at the same time low power dissipat......In this paper a review of different techniques used to implement highly optimized DSP systems is presented. The case of study is the implementation of parallel FIR filters aimed to applications characterized by high speed and high selectivity in frequency where at the same time low power...... on selective bit freezing, DPA-II, based on VDD voltage scaling, and DPA-III, based on power gating. Some theoreticaVsimuiative analysis of the introduced arithmetic errors and some implementation results are shown. A discussion on the suitability of these methodologies on standard cell technologies and FPGAs...

  2. Research on SINS Alignment Algorithm Based on FIR Filters

    Institute of Scientific and Technical Information of China (English)

    LIAN Jun-xiang; HU De-wen; WU Yuan-xin; HU Xiao-ping

    2007-01-01

    An inertial frame based alignment (IFBA) method is presented, especially for the applications on a rocking platform, e.g., marine applications. Defining the initial body frame as the inertial frame, the IFBA method achieves the alignment by virtue of a cascade of low-pass FIR filters, which attenuate the disturbing acceleration and maintain the gravity vector. The aligning time rests with the orders of the FIR filter group, and the method is suitable for large initial misali gnment case. An alignment scheme comprising a coarse phase by the IFBA method an d a fine phase by a Kalman filter is presented. Both vehicle-based and ship-based alignment experiments were carried out. The results show that the proposed scheme converges much faster than the traditional method at no cost of precision and also works well under any large initial misalignment.

  3. Synthesis of Band Filters and Equalizers Using Microwav FIR Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Deibele, C.; /Fermilab

    2000-01-01

    It is desired to design a passive bandpass filter with both a linear phase and flat magnitude response within the band and also has steep skirts. Using the properties of both coupled lines and elementary FIR (Finite Impulse Response) signal processing techniques can produce a filter of adequate phase response and magnitude control. The design procedure will first be described and then a sample filter will then be synthesized and results shown.

  4. FIR colours and SEDs of nearby galaxies observed with Herschel

    OpenAIRE

    Boselli, A.; Bock, J.; Bradford, M; Fadda, D.; Levenson, L.; Lu, N.; Schulz, B.; Wright, G.

    2010-01-01

    We present infrared colours (in the 25−500 μm spectral range) and UV to radio continuum spectral energy distributions of a sample of 51 nearby galaxies observed with SPIRE on Herschel. The observed sample includes all morphological classes, from quiescent ellipticals to active starbursts. Active galaxies have warmer colour temperatures than normal spirals. In ellipticals hosting a radio galaxy, the far-infrared (FIR) emission is dominated by the synchrotron nuclear emission. The colour temper...

  5. FIR colours and SEDs of nearby galaxies observed with Herschel

    OpenAIRE

    Boselli, A.; Ciesla, L.; Buat, V.; Cortese, L.; Auld, R.; Baes, Maarten; Bendo, GJ; S. Bianchi; Bock, J.; Bomans, DJ; Bradford, M; Castro-Rodriguez, N.; Chanial, P.; Charlot, S.; Clemens, M.

    2010-01-01

    We present infrared colours (in the 25-500 mu m spectral range) and UV to radio continuum spectral energy distributions of a sample of 51 nearby galaxies observed with SPIRE on Herschel. The observed sample includes all morphological classes, from quiescent ellipticals to active starbursts. Active galaxies have warmer colour temperatures than normal spirals. In ellipticals hosting a radio galaxy, the far-infrared (FIR) emission is dominated by the synchrotron nuclear emission. The colour temp...

  6. Research on Change of Rhizosphere Soil Properties of Chinese fir Plantation

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This article emphatically reviews the difference of soil biological activities, biochemical activities and soil chemical properties between the rhizosphere and non-rhizosphere soil of first rotation of Chinese fir (Cunninghamia lanceolata (Lamb) Hook) plantation. It also reviews their dynamic patterns during Chinese fir plantation development. The results show that the contents of organic and inorganic nutrients in the rhizosphere soil of young, half-mature and near-mature Chinese fir of first-rotation ...

  7. Action of Douglas Fir Tussock Moth Larvae and Their Microflora on Dietary Terpenes

    OpenAIRE

    Andrews, R E; Spence, K. D.

    1980-01-01

    A single type of bacterium, tentatively identified as a member of the genus Bacillus, was isolated from 2 of 20 midguts of Douglas fir tussock moth larvae being fed a diet of fir needles. No bacteria could be isolated from most midguts. Although spherically shaped bodies were present in the food bolus, these bodies, if microorganisms, could not be distinguished from spherical bodies associated with the plant tissue. The Douglas fir tussock moth dietary terpenes were altered during their passa...

  8. [Selection of biomass estimation models for Chinese fir plantation].

    Science.gov (United States)

    Li, Yan; Zhang, Jian-guo; Duan, Ai-guo; Xiang, Cong-wei

    2010-12-01

    A total of 11 kinds of biomass models were adopted to estimate the biomass of single tree and its organs in young (7-year-old), middle-age (16-year-old), mature (28-year-old), and mixed-age Chinese fir plantations. There were totally 308 biomass models fitted. Among the 11 kinds of biomass models, power function models fitted best, followed by exponential models, and then polynomial models. Twenty-one optimal biomass models for individual organ and single tree were chosen, including 18 models for individual organ and 3 models for single tree. There were 7 optimal biomass models for the single tree in the mixed-age plantation, containing 6 for individual organ and 1 for single tree, and all in the form of power function. The optimal biomass models for the single tree in different age plantations had poor generality, but the ones for that in mixed-age plantation had a certain generality with high accuracy, which could be used for estimating the biomass of single tree in different age plantations. The optimal biomass models for single Chinese fir tree in Shaowu of Fujin Province were used to predict the single tree biomass in mature (28-year-old) Chinese fir plantation in Jiangxi Province, and it was found that the models based on a large sample of forest biomass had a relatively high accuracy, being able to be applied in large area, whereas the regional models with small sample were limited to small area.

  9. Impact of Continuous Chinese Fir Monoculture on Soil

    Institute of Scientific and Technical Information of China (English)

    YANG Yu-Sheng; LIU Chun-Jiang; W. KUTSCH; CHEN Guang-Shui; YU Xin-Tuo

    2004-01-01

    Soil properties were investigated in sites where three succeeding generations of Chinese fir (Cunninghamia lanceolata (Lambert) Hooker) in Nanping, Fujian, China, were cultivated in order to show the impact of a repeated monoculture on site productivity. Compared with the first generation (FG) stand the soil structure deteriorated in the second generation (SG) and the third generation (TG) stands. For instance,the destruction rate of the peds increased by 55%-115% in the SG and the TG stands compared to the FG stand. Soil nutrient storage and nutrient availability also decreased in the SG and the TG stands. For surface soils of 0-20 cm, the organic matter content, total N and P, and available N and P decreased by 3%-20% relative to those in the FG stand. For many soil parameters, the differences between the FG stand and the SG and the TG stands were statistically significant (LSD test, P < 0.05). Furthermore, with each succeeding generation of Chinese fir, the total number of soil microbes declined, the soil enzyme activity weakened, and the soil biological activity decreased. In order to maintain sustainable site productivity, new silvicultural practices need to be developed for management of Chinese fir plantations.

  10. Herschel observations of FIR emission lines in brightest cluster galaxies

    CERN Document Server

    Edge, A C; Mittal, R; Allen, S W; Baum, S A; Boehringer, H; Bregman, J N; Bremer, M N; Combes, F; Crawford, C S; Donahue, M; Egami, E; Fabian, A C; Hamer, S L; Hatch, N A; Jaffe, W; Johnstone, R M; McNamara, B R; O'Dea, C P; Popesso, P; Quillen, A C; Salome, P; Sarazin, C L; Voit, G M; Wilman, R J; Wise, M W

    2010-01-01

    The question of how much gas cools in the cores of clusters of galaxies has been the focus of many, multiwavelength studies in the past 30 years. In this letter we present the first detections of the strongest atomic cooling lines, [C II], [O I] and [N I] in two strong cooling flow clusters, A1068 and A2597, using Herschel PACS. These spectra indicate that the substantial mass of cold molecular gas (>10^9 Mo) known to be present in these systems is being irradiated by intense UV radiation, most probably from young stars. The line widths of these FIR lines indicate that they share dynamics similar but not identical to other ionised and molecular gas traced by optical, near-infrared and CO lines. The relative brightness of the FIR lines compared to CO and FIR luminosity is consistent with other star-forming galaxies indicating that the properties of the molecular gas clouds in cluster cores and the stars they form are not unusual. These results provide additional evidence for a reservoir of cold gas that is fed...

  11. Growth Response of Silver Fir and Bosnian Pine from Kosovo

    Directory of Open Access Journals (Sweden)

    Elvin Toromani

    2010-06-01

    Full Text Available Background and Purpose: This paper explore the growth-climate relationships in total ring width chronologies of silver fir (Abies alba Mill. and Bosnian pine (Pinus heldreichii Christ. The objective of this study is to quantify the climate influence on radial growth of both species. The relationships between climate and ring widths were analyzed using extreme growing years (called pointer years, simple correlations and response functions analysis (bootstrapped coefficients. The objectives of this study were: (1 to define the pattern of climatic response of each species, (2 to highlight the influence of local ecological conditions on tree's growth, and (3 to compare the response of silver fir and Bosnian pine to climate. Responses of total ring width to climate were estimated by establishing the mean relationship between growth and climate through simple correlations analysis and bootstrapped response functions. The response to climatic variability was also assessed by analyzing pointer years which correspond to abrupt changes in growth pattern and revealing the tree-growth response to extreme climatic events. For the period 1908-2008 the mean sensitivity (MS of total ring width chronology for Bosnian pine (0.209 was higher than silver fir (0.169 suggesting that Bosnian pine is more sensitive to climate (pointer years were more frequent in ring width chronology of Bosnian pine than in silver fir ring width chronology. The high values of first-order autocorrelations for Bosnian pine (0.674 indicated a strong dependence of current growth on the previous year’s growth. Pointer years analysis underlined the high sensitivity to spring temperatures and precipitation for both species. Radial growth for both species depends strongly on spring climate variables (temperatures and precipitation which play a significant role particularly for earlywood production. Material and Methods: We selected 12 silver fir trees and 15 Bosnian pine trees and took two 5

  12. Species turnover in tropical montane forest avifauna links to climatic correlates

    Directory of Open Access Journals (Sweden)

    Chi-Feng Tsai

    2015-01-01

    Full Text Available We examined avifauna richness and composition in Taiwan’s tropical montane forests, and compared to historical records dated 22 years ago. A richness attrition of 44 species caused a discrepancy of 30.2%, and an estimated yearly turnover of 2.2%. More resident species that were narrower or lower in elevation distribution, insectivores/omnivores, small to medium-sized, forest/open-field dwelling, and canopy/ground foragers, vanished; whereas piscivores, carnivores, riparian- and shrub-dwellers, ground and mid-layer foragers, and migrants suffered by higher proportions. Occurrence frequencies of persistent species remained constant but varied among ecological groups, indicating an increased homogeneity for smaller-sized insectivores/omnivores dwelling in the forest canopy, shrub, or understory. While the overall annual temperature slightly increased, a relatively stable mean temperature was replaced by an ascending trend from the mid-1990s until 2002, followed by a cooling down. Mean maximum temperatures increased but minimums decreased gradually over years, resulting in increasing temperature differences up to over 16 °C. This accompanied an increase of extreme typhoons affecting Taiwan or directly striking these montane forests during the last decade. These results, given no direct human disturbances were noted, suggest a link between the species turnover and recent climate change, and convey warning signs of conservation concerns for tropical montane assemblages.

  13. A MCDM Analysis of the Roşia Montană Gold Mining Project

    Directory of Open Access Journals (Sweden)

    Adriana Mihai

    2015-06-01

    Full Text Available The need and estimated utility for a structured analysis of the Roşia Montană gold exploitation project have been palpable in the Romanian public sphere during the last 15 years and there is a vast amount of conflicting information and opinions on the benefits and risks involved. This article provides a comprehensive decision analysis of the Roşia Montană project. Over 100 documents from the past years have been gathered regarding the Roşia Montană mining project, which cover the main official, formal and less formal documents covering the case and produced by a wide range of stakeholders. These were then analyzed while designing a multi-criteria tree including the relevant perspectives under which the most commonly discussed four alternatives were analyzed. The result of this can be translated into a valuable recommendation for the mining company and for the political decision-makers. If these stakeholders want the continuation of the project and its acceptance by civil society, the key challenge is to increase the transparency of the process and improve the credibility and legal aspects; if these aspects cannot be met, the decision-makers need to pay attention to the alternatives available for a sustainable development in the area.

  14. Two pulses of diversification across the Isthmus of Tehuantepec in a montane Mexican bird fauna.

    Science.gov (United States)

    Barber, B R; Klicka, J

    2010-09-07

    Understanding the evolutionary history of the species in a particular region provides insights into how that fauna was formed. Of particular interest to biogeographers is examining the impact a geographical barrier had in generating temporal genetic diversity among codistributed species. We examined the impact a major New World barrier, the Isthmus of Tehuantepec (IT) in southern Mexico, had on a regional bird fauna. Specifically, genetic data from 10 montane-forest bird taxa were analysed using approximate Bayesian computation (ABC) to test the hypothesis of simultaneous intraspecific diversification at the IT. Because effective population size (N(e)) has the greatest impact on coalescent times, thereby affecting tests of divergence among codistributed taxa, we chose priors for both current and ancestral N(e) using empirical estimates of theta. The ABC method detected two discrete diversification events. Subsequent analysis with the number of diversification events constrained to two suggests that four taxa diverged in an older event, with the remaining six diverging more recently. Application of a range of mutation rates from 2.0 to 5.0% Myr(-1) places both events within the Pleistocene or Late Pliocene, suggesting that fluctuations in montane habitat induced by climate cycles and a late Pliocene seaway may have fractured this montane bird fauna. The results presented here suggest this avian fauna responded in a relatively concerted fashion over the last several million years.

  15. Power Efficient Design of Parallel/Serial FIR Filters in RNS

    DEFF Research Database (Denmark)

    Petricca, Massimo; Albicocco, Pietro; Cardarilli, Gian Carlo

    2012-01-01

    It is well known that the Residue Number System (RNS) provides an efficient implementation of parallel FIR filters especially when the filter order and the dynamic range are high. The two main drawbacks of RNS, need of converters and coding overhead, make a serialized implementation of the FIR fi...

  16. Population buildup and vertical spread of dwarf mistletoe on young red and white firs in California

    Science.gov (United States)

    Robert F. Scharpf; John R. Parmeter Jr.

    1976-01-01

    Rate of population buildup of dwarf mistletoe, Arceuthobium abietinum Engelm. ex Munz., was slow in most small red firs and white firs 12 to 15 years after inoculation with the parasite. Where population buildup did occur, it remained clustered in the lower portions of tree crowns near inoculation sites. Maximum distance of vertical spread was 16...

  17. Conversion of SPORL pretreated Douglas fir forest residues into microbial lipids with oleaginous yeasts

    Science.gov (United States)

    Douglas fir is the dominant commercial tree grown in the United States. In this study Douglas fir residue was converted to single cell oils using oleaginous yeasts. Monosaccharides were extracted from the woody biomass by pretreating with sulfite and dilute sulfuric acid (SPORL process) and hydrol...

  18. Belowground competition from overstory trees influences Douglas-fir sapling morphology in thinned stands

    Science.gov (United States)

    Warren D. Devine; Timothy B. Harrington

    2009-01-01

    We evaluated effects of belowground competition on morphology of naturally established coast Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco) saplings in 60- to 80-year-old thinned Douglas-fir stands in southwestern Washington. We separately quantified belowground competition from overstory and understory sources...

  19. An audio FIR-DAC in a BCD process for high power Class-D amplifiers

    NARCIS (Netherlands)

    Doorn, T.S.; Tuijl, van E.; Schinkel, D.; Annema, A.J.; Berkhout, M.; Nauta, B.

    2005-01-01

    A 322 coefficient semi-digital FIR-DAC using a 1-bit PWM input signal was designed and implemented in a high voltage, audio power bipolar CMOS DMOS (BCD) process. This facilitates digital input signals for an analog class-D amplifier in BCD. The FIR-DAC performance depends on the ISI-resistant natur

  20. An audio FIR-DAC in a BCD process for high power Class-D amplifiers

    NARCIS (Netherlands)

    Doorn, T.S.; van Tuijl, Adrianus Johannes Maria; Schinkel, Daniel; Annema, Anne J.; Berkhout, M.; Berkhout, M.; Nauta, Bram

    A 322 coefficient semi-digital FIR-DAC using a 1-bit PWM input signal was designed and implemented in a high voltage, audio power bipolar CMOS DMOS (BCD) process. This facilitates digital input signals for an analog class-D amplifier in BCD. The FIR-DAC performance depends on the ISI-resistant

  1. Properties of predictor based on relative neighborhood graph localized FIR filters

    DEFF Research Database (Denmark)

    Sørensen, John Aasted

    1995-01-01

    A time signal prediction algorithm based on relative neighborhood graph (RNG) localized FIR filters is defined. The RNG connects two nodes, of input space dimension D, if their lune does not contain any other node. The FIR filters associated with the nodes, are used for local approximation...

  2. Domes, Ash and Dust - Controls on soil genesis in a montane catchment of the Valles Caldera, New Mexico

    Science.gov (United States)

    Rasmussen, C.; Meding, S. M.; Vazquez, A.; Chorover, J.

    2012-12-01

    Soil genesis in volcanic terrain may be controlled by complex assemblages of parent materials and local topography. The objective of this work was to quantify topographic and parent material controls on soil and catchment evolution in a mixed conifer, montane catchment in the Valles Caldera, New Mexico, as part of the Jemez River Basin Critical Zone Observatory. The field site is a 16 ha catchment at an elevation of 3,000 m, with a frigid soil temperature regime (0-8 *C), ustic soil moisture regime with bimodal precipitation of winter snowfall and convective summer rainfall (880 mm yr-1), and an overstory dominated by spruce and fir with dense grass cover in open areas. The catchment is located on the resurgent Redondo Dome that uplifted shortly after the last major eruption of the Valles Caldera 1.2 My ago. The dome includes a complex assemblage of pre-eruptive caldera materials and extant sedimentary rocks embedded within a welded, hydrothermally altered rhyolitic tuff. We sampled a transect of seven soil profiles spanning the dominant east-west aspect of the catchment across a catena with profiles located in summit, backslope, footslope, and toeslope positions. Soil morphology was described in the field and soil samples analyzed using a range of geochemical and mineralogical techniques including quantitative and qualitative x-ray diffraction of bulk samples and particle size fractions, elemental analysis by x-ray fluorescence, and laser particle size analysis. The data indicated strong landscape position control on soil drainage, grading from well-drained summits to poorly-drained toeslope positions based on the presence/absence of redoximorphic features. The drainage patterns were coupled with downslope thickening of dark, organic matter rich surface horizons, likely a function of both in situ organic matter production and downslope colluvial transport of carbon rich surface materials. Mineralogical and geochemical data indicated clear within profile lithologic

  3. Thematic trip: "Save Roşia MontanÄă"

    Science.gov (United States)

    Eugenia, Marcu

    2015-04-01

    The name Roşia Montană, situated in Transylvania, became well known after a Romanian-Canadian company, Roşia Montană Gold Company (RMGC), obtained the concession license on exploitation for gold and silver minerals in the Roşia Montană area. The project consists of opening the largest surface gold mines in Europe using cyanide, which will include four open pits and a processing plant for gold and silver in The Roşia Valley and a tailings facility with an area of 367 hectares in the Corna Valley. One of the main fears is related to a possible ecological accident like the one in Baia Mare in 2000, when a tailing facility dam break led to cyanide pollution of Tisa and Danube rivers that resulted in the death of 1,200 tons of fish and contamination of water resources for 2 million people. This thematic trip is important for the scientific preparation of students and an opportunity to educate them in the spirit of environmental protection. The training and education of students will require assimilation and understanding, actively and consciously, using the knowledge acquired during the compulsory curriculum and training skills. REASON: The continuous degradation of the environment is a major crisis due to human intervention in nature, and the proposed Roşia Montană mining project will continue this trend. The company proposes to extract gold from mines by using the gold separation technique using cyanide, a process that involves destroying a total area of 16 km² which includes 5 mountains, 7 churches, 11 cemeteries and the ruins of Alburnus Maior Citadel, as well as creating pollution that would last for hundreds of years. The extraction of gold from low-grade ores using cyanide processes was estimated to result in a worldwide emission of 45,300 tons of hydrogen cyanide. Environmental education for a healthy life has children as target group, because they are the trustees and beneficiaries of tomorrow's natural resources and can influence the attitudes of

  4. Characterisation of pulsed Carbon fiber illuminators for FIR instrument calibration

    CERN Document Server

    Henrot-Versillé, S; Couchot, F

    2007-01-01

    We manufactured pulsed illuminators emitting in the far infrared for the Planck-HFI bolometric instrument ground calibrations. Specific measurements have been conducted on these light sources, based on Carbon fibers, to understand and predict their properties. We present a modelisation of the temperature dependence of the thermal conductivity and the calorific capacitance of the fibers. A comparison between simulations and bolometer data is given, that shows the coherence of our model. Their small time constants, their stability and their emission spectrum pointing in the submm range make these illuminators a very usefull tool for calibrating FIR instruments.

  5. Analysis of the growth characteristics of a 450-year-old silver fir tree

    Directory of Open Access Journals (Sweden)

    Pantić Damjan

    2015-01-01

    Full Text Available The growth characteristics of silver fir are of high importance for selection forest management, and for the current aims laid out in Serbia’s forest management focused on increasing the share of silver firs in Serbia’s growing stock. With the objective of increasing the understanding of the growth characteristics of silver fir, the growth of two silver fir trees felled during forest site production research on Mt. Goč, located in Central Serbia, have been analyzed. Both trees showed significant differences in their growth dynamics over long periods as results of micro-site and micro-stand effects (primarily ambient light regime. The common growth characteristic of the two trees, a 450-year-old tree as the main study object (labeled Tree A and a 270-year-old Tree B is a long stagnation stage. For Tree A the latent phase, with small interruptions, lasted 410 years; one phase lasted 330 years in continuity, which is the longest period of silver fir stagnation recorded in Europe. Tree B showed a long-lasting stagnation stage that lasted 170 years. The long stagnation stage of Tree A, characterized by an average diameter increment of 1.4 mm/year (average growth ring width of 0.7 mm and an average height increment of 0.08 m/year, shows the extraordinary silver fir capacity for physiological survival in complete shade. This study adds to the existing knowledge of the shade tolerance of the silver fir. Therefore, the silver fir belongs to the group of extremely shade-tolerant tree species. This characteristic makes silver fir an irreplaceable tree species in the selection forest structure. It offers a wide range of silvicultural flexibility in the management of these forests, and is applicable to silver fir selection Serbia’s forests. [Projekat Ministarstva nauke Republike Srbije, br. EVBR 37008: Sustainable management of total forest potentials in the Republic of Serbia

  6. Structural properties of laminated Douglas fir/epoxy composite material

    Energy Technology Data Exchange (ETDEWEB)

    Spera, D.A. (National Aeronautics and Space Administration, Cleveland, OH (USA). Lewis Research Center); Esgar, J.B. (Sverdrup Technology, Inc., Cleveland, OH (USA)); Gougeon, M.; Zuteck, M.D. (Gougeon Bros., Bay City, MI (USA))

    1990-05-01

    This publication contains a compilation of static and fatigue and strength data for laminated-wood material made from Douglas fir and epoxy. Results of tests conducted by several organizations are correlated to provide insight into the effects of variables such as moisture, size, lamina-to-lamina joint design, wood veneer grade, and the ratio of cyclic stress to steady stress during fatigue testing. These test data were originally obtained during development of wood rotor blades for large-scale wind turbines of the horizontal-axis (propeller) configuration. Most of the strength property data in this compilation are not found in the published literature. Test sections ranged from round cylinders 2.25 in. in diameter to rectangular slabs 6 in. by 24 in. in cross section and approximately 30 ft long. All specimens were made from Douglas fir veneers 0.10 in. thick, bonded together with the WEST epoxy system developed for fabrication and repair of wood boats. Loading was usually parallel to the grain. Size effects (reduction in strength with increase in test volume) are observed in some of the test data, and a simple mathematical model is presented that includes the probability of failure. General characteristics of the wood/epoxy laminate are discussed, including features that make it useful for a wide variety of applications. 9 refs.

  7. MODIFIED MICROPIPLINE ARCHITECTURE FOR SYNTHESIZABLE ASYNCHRONOUS FIR FILTER DESIGN

    Directory of Open Access Journals (Sweden)

    Basel Halak

    2016-02-01

    Full Text Available The use of asynchronous design approaches to construct digital signal processing (DSP systems is a rapidly growing research area driven by a wide range of emerging energy constrained applications such as wireless sensor network, portable medical devices and brain implants. The asynchronous design techniques allow the construction of systems which are samples driven, which means they only dissipate dynamic energy when there processing data and idle otherwise. This inherent advantage of asynchronous design over conventional synchronous circuits allows them to be energy efficient. However the implementation flow of asynchronous systems is still difficult due to its lack of compatibility with industrystandard synchronous design tools and modelling languages. This paper devises a novel asynchronous design for a finite impulse response (FIR filter, an essential building block of DSP systems, which is synthesizable and suitable for implementation using conventional synchronous systems design flow and tools. The proposed design is based on a modified version of the micropipline architecture and it is constructed using four phase bundled data protocol. A hardware prototype of the proposed filter has been developed on an FPGA, and systematically verified. The results prove correct functionality of the novel design and a superior performance compared to a synchronous FIR implementation. The findings of this work will allow a wider adoption of asynchronous circuits by DSP designers to harness their energy and performance benefits.

  8. POLARIZATION OF FIR EMISSION FROM T-TAURI DISKS

    Directory of Open Access Journals (Sweden)

    J. Cho

    2009-01-01

    Full Text Available Recent observations of 850 gm sub-mm polarization from T-Tauri disks open up the possibility of studying the magnetic eld structure within protostellar disks. The degree of polarization is around 3% and the direction of polarization is perpendicular to the disk. Since thermal emission from dust grains dominates the spectral energy distribution at sub-mm/far-infrared (FIR wavelengths, dust grains are thought to be the cause of the polarization. We discuss grain alignment by radiation and we explore the efficiency of dust alignment in T-Tauri disks. The calculations show that dust grains located far away from the central proto-star are more efficiently aligned. In the presence of a regular magnetic eld, the aligned grains produce polarized emission in sub-mm/FIR wavelengths. The direction of polarization is perpendicular to the local magnetic eld direction. When we use a recent T-Tauri disk model and take a Mathis-Rumpl-Nordsieck-type distribution with maximum grain size of 500{1000 -m, the degree of polarization is around 2{3% level at wavelengths larger than - 100 gm. Our work indicates that multifrequency infrared polarimetric studies of protostellar disks can provide good insights into the details of their magnetic structure. We also provide predictions for polarize emission for disks viewed at di erent wavelengths and viewing angles.

  9. Upgrade Plans for the C-Mod FIR Polarimeter

    Science.gov (United States)

    Watterson, R.; Garnier, D.; Irby, J.; Brower, D. L.; Xu, P.; Bergerson, W. F.; Ding, W. X.; Guttenfelder, W.; Marmar, E. S.

    2014-10-01

    The 3-chord FIR polarimeter presently deployed on C-Mod is capable of responding to both fast changes in the plasma equilibrium and high frequency fluctuations. It operates under ITER-like plasma conditions and magnetic fields, and uses an optical layout similar to that proposed for ITER. The details of this system and some results from the C-Mod 2012 campaign will be presented, along with the design of the upgrade that is now being implemented. The new system will provide horizontal chords near the mid-plane and low loss etalon windows to improve both the signal level and our ability to study magnetic fluctuations. The laser table has been relocated from the C-Mod cell to a shielded and climate controlled location, and improvements have been made to its acoustic isolation. New collimation optics, and a beam-line needed to convey the FIR beams into the tokamak port have been designed. Improvements to the detector electronics will also be discussed, as will initial testing of the laser system and reference detectors during C-Mod operation. Supported by USDoE Award DE-FC02-99ER54512.

  10. Structural properties of laminated Douglas fir/epoxy composite material

    Science.gov (United States)

    Spera, David A.; Esgar, Jack B.; Gougeon, Meade; Zuteck, Michael D.

    1990-01-01

    This publication contains a compilation of static and fatigue strength data for laminated-wood material made from Douglas fir and epoxy. Results of tests conducted by several organizations are correlated to provide insight into the effects of variables such as moisture, size, lamina-to-lamina joint design, wood veneer grade, and the ratio of cyclic stress to steady stress during fatigue testing. These test data were originally obtained during development of wood rotor blades for large-scale wind turbines of the horizontal-axis (propeller) configuration. Most of the strength property data in this compilation are not found in the published literature. Test sections ranged from round cylinders 2.25 in. in diameter to rectangular slabs 6 by 24 in. in cross section and approximately 30 ft. long. All specimens were made from Douglas fir veneers 0.10 in. thick, bonded together with the WEST epoxy system developed for fabrication and repair of wood boats. Loading was usually parallel to the grain. Size effects (reduction in strength with increase in test volume) are observed in some of the test data, and a simple mathematical model is presented that includes the probability of failure. General characteristics of the wood/epoxy laminate are discussed, including features that make it useful for a wide variety of applications.

  11. Projected range contractions of European protected oceanic montane plant communities: focus on climate change impacts is essential for their future conservation.

    Directory of Open Access Journals (Sweden)

    Rory L Hodd

    Full Text Available Global climate is rapidly changing and while many studies have investigated the potential impacts of this on the distribution of montane plant species and communities, few have focused on those with oceanic montane affinities. In Europe, highly sensitive bryophyte species reach their optimum occurrence, highest diversity and abundance in the north-west hyperoceanic regions, while a number of montane vascular plant species occur here at the edge of their range. This study evaluates the potential impact of climate change on the distribution of these species and assesses the implications for EU Habitats Directive-protected oceanic montane plant communities. We applied an ensemble of species distribution modelling techniques, using atlas data of 30 vascular plant and bryophyte species, to calculate range changes under projected future climate change. The future effectiveness of the protected area network to conserve these species was evaluated using gap analysis. We found that the majority of these montane species are projected to lose suitable climate space, primarily at lower altitudes, or that areas of suitable climate will principally shift northwards. In particular, rare oceanic montane bryophytes have poor dispersal capacity and are likely to be especially vulnerable to contractions in their current climate space. Significantly different projected range change responses were found between 1 oceanic montane bryophytes and vascular plants; 2 species belonging to different montane plant communities; 3 species categorised according to different biomes and eastern limit classifications. The inclusion of topographical variables in addition to climate, significantly improved the statistical and spatial performance of models. The current protected area network is projected to become less effective, especially for specialised arctic-montane species, posing a challenge to conserving oceanic montane plant communities. Conservation management plans need

  12. RADIO OBSERVATIONS OF THE STAR FORMATION ACTIVITIES IN THE NGC 2024 FIR 4 REGION

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Minho; Kang, Miju [Korea Astronomy and Space Science Institute, 776 Daedeokdaero, Yuseong, Daejeon 305-348 (Korea, Republic of); Lee, Jeong-Eun, E-mail: minho@kasi.re.kr [School of Space Research, Kyung Hee University, Yongin, Gyeonggi 446-701 (Korea, Republic of)

    2015-07-15

    Star formation activities in the NGC 2024 FIR 4 region were studied by imaging centimeter continuum sources and water maser sources using several archival data sets from the Very Large Array. The continuum source VLA 9 is elongated in the northwest–southeast direction, consistent with the FIR 4 bipolar outflow axis, and has a flat spectrum in the 6.2–3.6 cm interval. The three water maser spots associated with FIR 4 are also distributed along the outflow axis. One of the spots is located close to VLA 9, and another one is close to an X-ray source. Examinations of the positions of compact objects in this region suggest that the FIR 4 cloud core contains a single low-mass protostar. VLA 9 is the best indicator of the protostellar position. VLA 9 may be a radio thermal jet driven by this protostar, and it is unlikely that FIR 4 contains a high-mass young stellar object (YSO). A methanol 6.7 GHz maser source is located close to VLA 9, at a distance of about 100 AU. The FIR 4 protostar must be responsible for the methanol maser action, which suggests that methanol class II masers are not necessarily excited by high-mass YSOs. Also discussed are properties of other centimeter continuum sources in the field of view and the water masers associated with FIR 6n. Some of the continuum sources are radio thermal jets, and some are magnetically active young stars.

  13. Leaf litter decomposition rates increase with rising mean annual temperature in Hawaiian tropical montane wet forests

    Directory of Open Access Journals (Sweden)

    Lori D. Bothwell

    2014-12-01

    Full Text Available Decomposing litter in forest ecosystems supplies nutrients to plants, carbon to heterotrophic soil microorganisms and is a large source of CO2 to the atmosphere. Despite its essential role in carbon and nutrient cycling, the temperature sensitivity of leaf litter decay in tropical forest ecosystems remains poorly resolved, especially in tropical montane wet forests where the warming trend may be amplified compared to tropical wet forests at lower elevations. We quantified leaf litter decomposition rates along a highly constrained 5.2 °C mean annual temperature (MAT gradient in tropical montane wet forests on the Island of Hawaii. Dominant vegetation, substrate type and age, soil moisture, and disturbance history are all nearly constant across this gradient, allowing us to isolate the effect of rising MAT on leaf litter decomposition and nutrient release. Leaf litter decomposition rates were a positive linear function of MAT, causing the residence time of leaf litter on the forest floor to decline by ∼31 days for each 1 °C increase in MAT. Our estimate of the Q10 temperature coefficient for leaf litter decomposition was 2.17, within the commonly reported range for heterotrophic organic matter decomposition (1.5–2.5 across a broad range of ecosystems. The percentage of leaf litter nitrogen (N remaining after six months declined linearly with increasing MAT from ∼88% of initial N at the coolest site to ∼74% at the warmest site. The lack of net N immobilization during all three litter collection periods at all MAT plots indicates that N was not limiting to leaf litter decomposition, regardless of temperature. These results suggest that leaf litter decay in tropical montane wet forests may be more sensitive to rising MAT than in tropical lowland wet forests, and that increased rates of N release from decomposing litter could delay or prevent progressive N limitation to net primary productivity with climate warming.

  14. Facilitating adaptation in montane plants to changing precipitation along an elevation gradient

    Science.gov (United States)

    Hess, Steve; Leopold, Christina

    2017-01-01

    Montane plant communities throughout the world have responded to changes in precipitation and temperature regimes by shifting ranges upward in elevation. Continued warmer, drier climate conditions have been documented and are projected to increase in high-elevation areas in Hawai‘i, consistent with climate change effects reported in other environments throughout the world. Organisms that cannot disperse or adapt biologically to projected climate scenarios in situ may decrease in distributional range and abundance over time. Restoration efforts will need to accommodate future climate change and account for the interactive effects of existing invasive species to ensure long-term persistence. As part of a larger, ongoing restoration effort, we hypothesized that plants from a lower-elevation forest ecotype would have higher rates of survival and growth compared to high-elevation forest conspecifics when grown in common plots along an elevation gradient. We monitored climate conditions at planting sites to identify whether temperature or rainfall influenced survival and growth after 20 weeks. We found that origin significantly affected survival in only one of three native montane species, Dodonaea viscosa. Contrary to our hypothesis, 75.2% of seedlings from high-elevation origin survived in comparison to 58.7% of seedlings from low elevation across the entire elevation gradient. Origin also influenced survival in linearized mixed models that controlled for temperature, precipitation, and elevation in D. viscosa and Chenopodium oahuense. Only C. oahuense seedlings had similar predictors of growth and survival. There were no common patterns of growth or survival between species, indicating that responses to changing precipitation and emperature regimes varied between montane plant species. Results also suggest that locally sourced seed is important to ensure highest survival at restoration sites. Further experimentation on larger spatial and temporal scales is necessary

  15. Effects of mist acidity and ambient ozone removal on montane red spruce

    Energy Technology Data Exchange (ETDEWEB)

    Vann, D.R. [Pennsylvania Univ., Philadelphia, PA (United States). Dept. of Biology; Strimbeck, D.R.; Johnson, A.H. [Pennsylvania Univ., Philadelphia, PA (United States). Dept. of Geology

    1995-10-01

    The effects of acidic mists and ozone on several biochemical and growth parameters in mature montane red spruce were examined. Branch-size environmental chambers were used to introduce mists of controlled composition and to protect selected branches from ambient ozone and acidic mists. Mists of distilled water increased the end-of-season pigment concentration and shoot length of enclosed branches relative to ambient or artificial mists. Needle and twig weights and starch concentrations were not significantly altered by the acidic mist treatments. Removal of ambient ozone had no apparent effect on the variables measured. 8 figs., 2 tabs., 39 refs.

  16. Army ant raid attendance and bivouac checking behavior by Neotropical montane forest birds

    OpenAIRE

    O'Donnell, Sean; Kumar, Anjali; Logan, Corina J.

    2010-01-01

    This is the final version of the article. It first appeared from Wilson Ornithological Society via http://dx.doi.org/10.1676/09-156.1 We quantified resident and migrant bird attendance at army ant swarm raids (n  =  48) in a neotropical montane forest. All observations were during seasons when Nearctic migrant birds are present. Bird species differed in army ant raid-attending behavior. Resident bird species attended 2 to 54% of raids, while migrants attended at lower maximum frequencies (...

  17. Tropical land-cover change alters biogeochemical inputs to ecosystems in a Mexican montane landscape.

    Science.gov (United States)

    Ponette-González, A G; Weathers, K C; Curran, L M

    2010-10-01

    In tropical regions, the effects of land-cover change on nutrient and pollutant inputs to ecosystems remain poorly documented and may be pronounced, especially in montane areas exposed to elevated atmospheric deposition. We examined atmospheric deposition and canopy interactions of sulfate-sulfur (SO4(2-)-S), chloride (Cl-), and nitrate-nitrogen (NO(3-)-N) in three extensive tropical montane land-cover types: clearings, forest, and coffee agroforest. Bulk and fog deposition to clearings was measured as well as throughfall (water that falls through plant canopies) ion fluxes in seven forest and five coffee sites. Sampling was conducted from 2005 to 2008 across two regions in the Sierra Madre Oriental, Veracruz, Mexico. Annual throughfall fluxes to forest and coffee sites ranged over 6-27 kg SO4(2-)-S/ha, 12-69 kg Cl-/ha, and 2-6 kg NO(3-)-N/ha. Sulfate-S in forest and coffee throughfall was higher or similar to bulk S deposition measured in clearings. Throughfall Cl- inputs, however, were consistently higher than Cl- amounts deposited to cleared areas, with net Cl- fluxes enhanced in evergreen coffee relative to semi-deciduous forest plots. Compared to bulk nitrate-N deposition, forest and coffee canopies retained 1-4 kg NO(3-)-N/ha annually, reducing NO(3-)-N inputs to soils. Overall, throughfall fluxes were similar to values reported for Neotropical sites influenced by anthropogenic emissions, while bulk S and N deposition were nine- and eightfold greater, respectively, than background wet deposition rates for remote tropical areas. Our results demonstrate that land-cover type significantly alters the magnitude and spatial distribution of atmospheric inputs to tropical ecosystems, primarily through canopy-induced changes in fog and dry deposition. However, we found that land cover interacts with topography and climate in significant ways to produce spatially heterogeneous patterns of anion fluxes, and that these factors can converge to create deposition hotspots

  18. La Casa Roura de Domènech i Montaner a Canet de Mar (1892)

    OpenAIRE

    Borrell Mas, Jordi

    2010-01-01

    La Casa Roura o ca la Bianga de Canet de Mar va ser construïda i projectada per l’arquitecte Lluís Domènech i Montaner durant els anys 1889 i 1892 per encàrrec de la seva cunyada Francesca Roura i el seu marit Jacint de Capmany. Aquells van ser els primers anys del nou moviment cultural i arquitectònic anomenat Modernisme que s’estava desenvolupant a Catalunya. Paral•lelament, arreu d’Europa també s’hi estaven produint diferents moviments com l’Art Noveau, la Sezession, el Jugendstil o l’Styl...

  19. Decline of sacred fir (Abies religiosa) in a forest park south of Mexico City.

    Science.gov (United States)

    Alvarado R, D; De Bauer, L I; Galindo A, J

    1993-01-01

    Decline of sacred fir (Abies religiosa) trees in the high elevation forest park, Desierto de los Leones, located south of Mexico City, is described. Trees located in the windward zone (exposed to air masses from Mexico City) were the most severely affected, especially trees at the distal ends of ravines. Examination of tree growth rings indicated decreases in ring widths for the past 30 years. Polluted air from Mexico City may be an important causal factor in fir decline. Drought, due to excessive removal of soil water, insects, mites and pathogens, and poor forest management are possible contributing and interactive factors in fir decline.

  20. Ion Flux in Roots of Chinese Fir (Cunninghamia lanceolata (Lamb.) Hook) under Aluminum Stress

    OpenAIRE

    2016-01-01

    Chinese fir is a tall, fast-growing species that is unique to southern China. In Chinese fir plantations, successive plantings have led to a decline in soil fertility, and aluminum toxicity is thought to be one of the main reasons for this decline. In this study, Non-invasive Micro-test Technology was used to study the effect of aluminum stress on the absorption of 4 different ions in the roots of the Chinese fir clone FS01. The results are as follows: with increased aluminum concentration an...

  1. FIR Filter Implementation Based on the RNS with Diminished-1 Encoded Channel

    Directory of Open Access Journals (Sweden)

    Dragana Uros Zivaljevic

    2013-03-01

    Full Text Available A technique, based on the residue number system (RNS with diminished-1 encoded channel, has being used for implementing a finite impulse response (FIR digital filter. The proposed RNS architecture of the filter consists of three main blocks: forward and reverse converter and arithmetic processor for each channel. Architecture for residue to binary (reverse convertor with diminished-1 encoded channel has been proposed. Besides, for all RNS channels, the systolic design is used for the efficient  realization of FIR filter. A numerical example illustrates the principles of diminished-1 residue arithmetic, signal processing, and decoding for FIR filters.

  2. Active Cancellation of Acoustical Resonances with an FPGA FIR Filter

    CERN Document Server

    Ryou, Albert

    2016-01-01

    We present a novel approach to enhancing the bandwidth of a feedback-controlled mechanical system by digitally canceling acoustical resonances (poles) and anti-resonances (zeros) in the open-loop response via an FPGA FIR filter. By performing a real-time convolution of the feedback error signal with an inverse filter, we can suppress arbitrarily many poles and zeros below 100 kHz, each with a linewidth down to 10 Hz. We demonstrate the efficacy of this technique by canceling the ten largest mechanical resonances and anti-resonances of a high-finesse optical resonator, thereby enhancing the unity gain frequency by more than an order of magnitude. This approach is applicable to a broad array of stabilization problems including optical resonators, external cavity diode lasers, and scanning tunneling microscopes, and points the way to applying modern optimal control techniques to intricate linear acoustical systems.es to intricate linear acoustical systems.

  3. Active cancellation of acoustical resonances with an FPGA FIR filter

    Science.gov (United States)

    Ryou, Albert; Simon, Jonathan

    2017-01-01

    We present a novel approach to enhancing the bandwidth of a feedback-controlled mechanical system by digitally canceling acoustical resonances (poles) and anti-resonances (zeros) in the open-loop response via an FPGA FIR filter. By performing a real-time convolution of the feedback error signal with an inverse filter, we can suppress arbitrarily many poles and zeros below 100 kHz, each with a linewidth down to 10 Hz. We demonstrate the efficacy of this technique by canceling the ten largest mechanical resonances and anti-resonances of a high-finesse optical resonator, thereby enhancing the unity gain frequency by more than an order of magnitude. This approach is applicable to a broad array of stabilization problems including optical resonators, external cavity diode lasers, and scanning tunneling microscopes and points the way to applying modern optimal control techniques to intricate linear acoustical systems.

  4. Sigma Delta Modulation Based Ternary FIR Filter Mapping on FPGA

    Directory of Open Access Journals (Sweden)

    Tayabuddin Memon

    2011-07-01

    Full Text Available In this paper single-bit SDM (Sigma Delta Modulation based TFF (Ternary FIR Filter with balanced ternary coefficients (i.e. -1/0/+1 has been mapped on small commercially available FPGAs (Field Programmable Gate Arrays. Filter coefficients were obtained using second order sigma delta modulator. The filter structure is based on a hierarchical adder tree that can easily be pipelined for high performance purpose. Filter structure was coded in VHDL (Very High Speed Integrated Circuit Hardware Description Language and simulated in Quartus-II software. The filter exhibits low I/O (Input Output and core area usage and high performance-achieving clock speeds close to 200MHz on a low-cost FPGA and over 500MHz on a latest FPGA commercially available device. This single-bit ternary filter is intended to support video and audio processing applications in mobile communication systems.

  5. FIR colours and SEDs of nearby galaxies observed with Herschel

    CERN Document Server

    Boselli, A; Buat, V; Cortese, L; Auld, R; Baes, M; Bendo, G J; Bianchi, S; Bock, J; Bomans, D J; Bradford, M; Castro-Rodriguez, N; Chanial, P; Charlot, S; Clemens, M; Clements, D; Corbelli, E; Cooray, A; Cormier, D; Dariush, A; Davies, J; De Looze, I; Alighieri, S di Serego; Dwek, E; Eales, S; Elbaz, D; Fadda, D; Fritz, J; Galametz, M; Galliano, F; Garcia-Appadoo, D A; Gavazzi, G; Gear, W; Giovanardi, C; Glenn, J; Gomez, H; Griffin, M; Grossi, M; Hony, S; Hughes, T M; Hunt, L; Isaak, K; Jones, A; Levenson, L; Lu, N; Madden, S C; O'Halloran, B; Okumura, K; Oliver, S; Page, M; Panuzzo, P; Papageorgiou, A; Parkin, T; Perez-Fournon, I; Pierini, D; Pohlen, M; Rangwala, N; Rigby, E; Roussel, H; Rykala, A; Sabatini, S; Sacchi, N; Sauvage, M; Schulz, B; Schirm, M; Smith, M W L; Spinoglio, L; Stevens, J; Sundar, S; Symeonidis, M; Trichas, M; Vaccari, M; Verstappen, J; Vigroux, L; Vlahakis, C; Wilson, C; Wozniak, H; Wright, G; Xilouris, E M; Zeilinger, W; Zibetti, S

    2010-01-01

    We present infrared colours (in the 25-500 mic spectral range) and UV to radio continuum spectral energy distributions of a sample of 51 nearby galaxies observed with SPIRE on Herschel. The observed sample includes all morphological classes, from quiescent ellipticals to active starbursts. Active galaxies have warmer colour temperatures than normal spirals. In ellipticals hosting a radio galaxy, the far-infrared (FIR) emission is dominated bynthe synchrotron nuclear emission. The colour temperature of the cold dust is higher in quiescent E-S0a than in star-forming systems probably because of the different nature of their dust heating sources (evolved stellar populations, X-ray, fast electrons) and dust grain properties. In contrast to the colour temperature of the warm dust, the f350/f500 index sensitive to the cold dust decreases with star formation and increases with metallicity, suggesting an overabundance of cold dust or an emissivity parameter beta<2 in low metallicity, active systems.

  6. Intratree Variability of Cleavage Resistance of Chinese Fir from Plantation

    Institute of Scientific and Technical Information of China (English)

    XU Ming; REN Haiqing; LUO Xiuqin; YIN Yafang

    2006-01-01

    This paper studied the variation of cleavage resistance of Chinese fir wood from plantation.Six trees of 36 years old were investigated,and the cleavage resistance properties for 672 samples made of the trees were tested.The samples were cut from the sapwood and heartwood at different directions (south and north) and heights (1.3,3.3,5.3 and 7.3 m) of the trees.The result showed that:tangential cleavage resistance was higher than radial one, and cleavage resistance of sapwood was higher than that of heartwood,but there was no significant difference in cleavage resistances between sections of the north and the south of the trees.There was a little variation in cleavage resistance between the radial and tangential from butt to top log,which shows alittle decrease with the height from 1.3 to 5.3 m,but a rise in the top of the trees.

  7. Power and Aging Characterization of Digital FIR Filters Architectures

    DEFF Research Database (Denmark)

    Calimera, Andrea; Liu, Wei; Macii, Enrico;

    2012-01-01

    With technology scaling, newer metrics have been introduced, in addition to delay, area, and power dissipation, to characterize the behavior of digital systems. While dynamic and static power dissipation still remain the most serious concern at nanometer lengths (65nm and below), process-variatio......With technology scaling, newer metrics have been introduced, in addition to delay, area, and power dissipation, to characterize the behavior of digital systems. While dynamic and static power dissipation still remain the most serious concern at nanometer lengths (65nm and below), process......-variation, temperature and aging induced variations pose new challenges in the fabrication of the next generation of ICs. This work presents a detailed power and aging characterization of digital FIR filters in an industrial 45nm CMOS technology, and a design space exploration of different filter architectures...

  8. Active cancellation of acoustical resonances with an FPGA FIR filter.

    Science.gov (United States)

    Ryou, Albert; Simon, Jonathan

    2017-01-01

    We present a novel approach to enhancing the bandwidth of a feedback-controlled mechanical system by digitally canceling acoustical resonances (poles) and anti-resonances (zeros) in the open-loop response via an FPGA FIR filter. By performing a real-time convolution of the feedback error signal with an inverse filter, we can suppress arbitrarily many poles and zeros below 100 kHz, each with a linewidth down to 10 Hz. We demonstrate the efficacy of this technique by canceling the ten largest mechanical resonances and anti-resonances of a high-finesse optical resonator, thereby enhancing the unity gain frequency by more than an order of magnitude. This approach is applicable to a broad array of stabilization problems including optical resonators, external cavity diode lasers, and scanning tunneling microscopes and points the way to applying modern optimal control techniques to intricate linear acoustical systems.

  9. Study on Volatile Organic Components from Chinese Fir Wood

    Institute of Scientific and Technical Information of China (English)

    HUANG Luohua; QIN Tefu; OHIRA Tatsuro

    2006-01-01

    The volatile organic compounds(VOCs) are emitted by a wide array of products, which include a variety of chemicals, some of them may have short- and long-term adverse health effects. Several analytical instrument including gas chromatograph, high preferment liquid chromatograph, mass spectrometry and solid phase microextraction (SPME) technique were used in this study. The results showed the aldehyde and ketone components of Chinese fir wood were little composed of formaldehyde, syn-acetaldehyde, anti-acetadehyde and acrolein, VOCs obtained by Tenax GR absorber consisted of the major component cedrene (42.92%) and another 28 components, and the major components of the VOCs from the sample by using solid phase microextraction (SPME) technique were cedrene and cedrol.

  10. Watershed-scale modeling of streamflow change in incised montane meadows

    Science.gov (United States)

    Essaid, Hedeff I.; Hill, Barry R.

    2014-01-01

    Land use practices have caused stream channel incision and water table decline in many montane meadows of the Western United States. Incision changes the magnitude and timing of streamflow in water supply source watersheds, a concern to resource managers and downstream water users. The hydrology of montane meadows under natural and incised conditions was investigated using watershed simulation for a range of hydrologic conditions. The results illustrate the interdependence between: watershed and meadow hydrology; bedrock and meadow aquifers; and surface and groundwater flow through the meadow for the modeled scenarios. During the wet season, stream incision resulted in less overland flow and interflow and more meadow recharge causing a net decrease in streamflow and increase in groundwater storage relative to natural meadow conditions. During the dry season, incision resulted in less meadow evapotranspiration and more groundwater discharge to the stream causing a net increase in streamflow and a decrease in groundwater storage relative to natural meadow conditions. In general, for a given meadow setting, the magnitude of change in summer streamflow and long-term change in watershed groundwater storage due to incision will depend on the combined effect of: reduced evapotranspiration in the eroded meadow; induced groundwater recharge; replenishment of dry season groundwater storage depletion in meadow and bedrock aquifers by precipitation during wet years; and groundwater storage depletion that is not replenished by precipitation during wet years.

  11. Influence of climate on the presence of colour polymorphism in two montane reptile species.

    Science.gov (United States)

    Broennimann, Olivier; Ursenbacher, Sylvain; Meyer, Andreas; Golay, Philippe; Monney, Jean-Claude; Schmocker, Hans; Guisan, Antoine; Dubey, Sylvain

    2014-11-01

    The coloration of ectotherms plays an important role in thermoregulation processes. Dark individuals should heat up faster and be able to reach a higher body temperature than light individuals and should therefore have benefits in cool areas. In central Europe, montane local populations of adder (Vipera berus) and asp viper (Vipera aspis) exhibit a varying proportion of melanistic individuals. We tested whether the presence of melanistic V. aspis and V. berus could be explained by climatic conditions. We measured the climatic niche position and breadth of monomorphic (including strictly patterned individuals) and polymorphic local populations, calculated their niche overlap and tested for niche equivalency and similarity. In accordance with expectations, niche overlap between polymorphic local populations of both species is high, and even higher than that of polymorphic versus monomorphic montane local populations of V. aspis, suggesting a predominant role of melanism in determining the niche of ectothermic vertebrates. However, unexpectedly, the niche of polymorphic local populations of both species is narrower than that of monomorphic ones, indicating that colour polymorphism does not always enable the exploitation of a greater variability of resources, at least at the intraspecific level. Overall, our results suggest that melanism might be present only when the thermoregulatory benefit is higher than the cost of predation.

  12. Selective Extraction Methods for Aluminium, Iron and Organic Carbon from Montane Volcanic Ash Soils

    Institute of Scientific and Technical Information of China (English)

    B. JANSEN; F. H. TONNEIJCK; J. M. VERSTRATEN

    2011-01-01

    Montane volcanic ash soils contain disproportionate amounts of soil organic carbon and thereby play an often underestimated role in the global carbon cycle.Given the central role of A1 and Fe in stabilizing organic matter in volcanic ash soils,we assessed various extraction methods of A1,Fe,and C fractions from montane volcanic ash soils in northern Ecuador,aiming at elucidating the role of A1 and Fe in stabilizing soil organic matter (SOM).We found extractions with cold sodium hydroxide,ammonium oxalate/oxalic acid,sodium pyrophosphate,and sodium tetraborate to be particularly useful.Combination of these methods yielded information about the role of the mineral phase in stabilizing organic matter and the differences in type and degree of complexation of organic matter with Al and Fe in the various horizons and soil profiles.Sodium tetraborate extraction proved the only soft extraction method that yielded simultaneous information about the Al,Fe,and C fractions extracted.It also appeared to differentiate between SOM fractions of different stability.The fractions of copper chloride- and potassium chloride-extractable A1 were useful in assessing the total reactive and toxic Al fractions,respectively.The classical subdivision of organic matter into humic acids,fulvic acids,and humin added little useful information.The use of fulvic acids as a proxy for mobile organic matter as done in several model-based approaches seems invalid in the soils studied.

  13. The effects of Pleistocene climate change on biotic differentiation in a montane songbird clade from Wallacea.

    Science.gov (United States)

    Ng, Nathaniel S R; Wilton, Peter R; Prawiradilaga, Dewi Malia; Tay, Ywee Chieh; Indrawan, Mochamad; Garg, Kritika M; Rheindt, Frank E

    2017-09-01

    The role of Pleistocene Ice Age in tropical diversification is poorly understood, especially in archipelagos, in which glaciation-induced sea level fluctuations may lead to complicated changes in land distribution. To assess how Pleistocene land bridges may have facilitated gene flow in tropical archipelagos, we investigated patterns of diversification in the rarely-collected rusty-bellied fantail Rhipidura teysmanni (Passeriformes: Rhipiduridae) complex from Wallacea using a combination of bioacoustic traits and whole-genome sequencing methods (dd-RADSeq). We report a biogeographic leapfrog pattern in the vocalizations of these birds, and uncover deep genomic divergence among island populations despite the presence of intermittent land connections between some. We demonstrate how rare instances of genetic introgression have affected the evolution of this species complex, and document the presence of double introgressive mitochondrial sweeps, highlighting the dangers of using only mitochondrial DNA in evolutionary research. By applying different tree inference approaches, we demonstrate how concatenation methods can give inaccurate results when investigating divergence in closely-related taxa. Our study highlights high levels of cryptic avian diversity in poorly-explored Wallacea, elucidates complex patterns of Pleistocene climate-mediated diversification in an elusive montane songbird, and suggests that Pleistocene land bridges may have accounted for limited connectivity among montane Wallacean biota. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Community dynamics of a montane Fagus engleriana–Cyclobalanopsis multiervis mixed forest in Shennongjia, Hubei, China

    Directory of Open Access Journals (Sweden)

    Jielin Ge

    2012-11-01

    Full Text Available Montane evergreen and deciduous broad-leaved mixed forests are some of the main vegetation types in China. Specifically, the Fagus–Cyclobalanopsis mixed forest is a dominant forest community in themountainous region of Shennongjia. Using three datasets (2001, 2006, and 2010 from a permanent 120 m ×80 m plot in the montane evergreen and deciduous broad-leaved mixed forest in Shengnongjia, we analyzedthe dynamics of tree species composition and community structure for individual trees (DBH ≥ 4 cm. We found that total species number increased from 81 in 2001 to 84 in 2006, and then decreased to 83 in 2010. Dominant species remained constant throughout the study period, including Cyclobalanopsis multiervis, Fagus engleriana, Rhododendron hypoglaucum and Lithocarpus henryi. Stem number and basal area followed the same trend with an initial increase, followed by a decline. The mortality and recruitment of this survey plot changed substantially over the nine-year study period. Although an ice storm in 2008 had some impact on the community, the species richness and community structure did not alter significantly and the community appeared to be in a state of dynamic equilibrium with strong resilience to external disturbances.

  15. Characterization of the Montane Huntington Wildlife Forest Ecosystem Using Machine Learning Approaches from Remote Sensing Data

    Science.gov (United States)

    Li, Manqi

    Montane forests are susceptible to various stressors such as land use and climate change. Consequently, research on characterizing montane forest ecosystems should be conducted on a continuous basis for sustainable forest management. In this research, forest type mapping and change analysis, and biomass/carbon stock quantification were performed over a mountainous forest located in the central Adirondack Park, NY, by employing machine learning techniques at the plot level. Multi-temporal Landsat TM data were used to classify forest type cover and to detect forest cover changes for the past 20 years. Forest biomass and carbon stock quantification was then performed using full waveform LiDAR data collected in September 2011. Accuracies from the two case studies were in support of the versatility of machine learning approaches for forest and ecological investigation. Topographic characteristics affected the classification accuracy as well as the forest type change for the past 20 years. LiDAR-derived metrics, especially height-based ones, proved useful for quantifying biomass/carbon stock. Keywords: Landsat TM, full waveform LiDAR, forest classification, forest change analysis, biomass, carbon stock, machine learning

  16. Montane flora of the southern Langeberg, South Africa: a checklist of the flowering plants and ferns

    Directory of Open Access Journals (Sweden)

    D. J. Mcdonald

    1999-12-01

    Full Text Available The flora of the southern Langeberg is rich, w ith 1 228 species and intraspecific taxa (referred to collectively as species recorded in 361 genera and 105 families. An analysis of the montane flora of the southern Langeberg. Western Cape, South Africa based on an annotated checklist shows that the Asteraceae has the highest number of species per familv (167 and the genus  Erica has the most infrageneric taxa per genus (130 as well as the most endemic species (51. One endemic monotypic family, the Geissolomataceae, two endemic genera Geissoloma and Langebergia (Asteraceae and a total of 167 endemic species are found on the southern Langeberg The plant families of the southern Langeberg flora are ranked according to species-richness of the families and compared with floras of other areas (mainly montane in the Fynbos Biome and marginally to the east of this biome (the Amatole Mountains. The greatest similarity of ranking is evident betw een the plant families of the southern Langeberg and those of the Cape Hangklip Area.

  17. Montane and coastal species diversification in the economically important Mexican grasshopper genus Sphenarium (Orthoptera: Pyrgomorphidae).

    Science.gov (United States)

    Pedraza-Lara, Carlos; Barrientos-Lozano, Ludivina; Rocha-Sánchez, Aurora Y; Zaldívar-Riverón, Alejandro

    2015-03-01

    The genus Sphenarium (Pyrgomorphidae) is a small group of grasshoppers endemic to México and Guatemala that are economically and culturally important both as a food source and as agricultural pests. However, its taxonomy has been largely neglected mainly due to its conserved interspecific external morphology and the considerable intraspecific variation in colour pattern of some taxa. Here we examined morphological as well as mitochondrial and nuclear DNA sequence data to assess the species boundaries and evolutionary history in Sphenarium. Our morphological identification and DNA sequence-based species delimitation, carried out with three different approaches (DNA barcoding, general mixed Yule-coalescent model, Bayesian species delimitation), all recovered a higher number of putative species of Sphenarium than previously recognised. We unambiguously delimit seven species, and between five and ten additional species depending on the data/method analysed. Phylogenetic relationships within the genus strongly support two main clades, one exclusively montane, the other coastal. Divergence time estimates suggest late Miocene to Pliocene ages for the origin and most of the early diversification events in the genus, which were probably influenced by the formation of the Trans-Mexican Volcanic Belt. A series of Pleistocene events could have led to the current species diversification in both montane and coastal regions. This study not only reveals an overlooked species richness for the most popular edible insect in Mexico, but also highlights the influence of the dynamic geological and climatic history of the region in shaping its current diversity.

  18. Zooplankton assemblages in montane lakes and ponds of Mount Rainier National Park, Washington State, USA

    Science.gov (United States)

    Larson, G.L.; Hoffman, R.; McIntire, C.D.; Lienkaemper, G.; Samora, B.

    2009-01-01

    Water quality and zooplankton samples were collected during the ice-free periods between 1988 and 2005 from 103 oligotrophic montane lakes and ponds located in low forest to alpine vegetation zones in Mount Rainier National Park, Washington State, USA. Collectively, 45 rotifer and 44 crustacean taxa were identified. Most of the numerically dominant taxa appeared to have wide niche breadths. The average number of taxa per lake decreased with elevation and generally increased as maximum lake depths increased (especially for rotifers). With one exception, fish presence/absence did not explain the taxonomic compositions of crustacean zooplankton assemblages. Many rotifer species were common members of zooplankton assemblages in montane lakes and ponds in western North America, whereas the crustacean taxa were common to some areas of the west, but not others. Constraints of the environmental variables did not appear to provide strong gradients to separate the distributions of most zooplankton species. This suggests that interspecific competitive interactions and stochastic processes regulate the taxonomic structures of the zooplankton assemblages at the landscape level. Crustacean species that had broad niche breadths were associated with different rotifer taxa across the environmental gradients. Studies of zooplankton assemblages need to address both crustacean and rotifer taxa, not one or the other.

  19. Reproduction and morphology of the common lizard (Zootoca vivipara) from montane populations in Slovakia.

    Science.gov (United States)

    Horváthová, Terézia; Baláž, Michal; Jandzik, David

    2013-02-01

    The common lizard, Zootoca vivipara (Lichtenstein, 1823), shows high variation in life histories and morphology across its range, which comprises almost the entire Palearctic region. However, this variation is not congruent with the species phylogeny. This suggests an important role of the environment in shaping the variation in morphology and life histories of this species. As most data on life histories originate from only a small number of populations and do not cover the species' geographic range and phylogenetic diversity, to fill a gap and provide more information for future comparative studies we investigated reproduction and morphology in two montane populations from Slovakia, central Europe. This region is characterized by taxonomic and phylogenetic diversity and both montane and lowland ecological forms of the common lizard occur here. The common lizards from the Slovak populations are sexually dimorphic, with females having larger body and abdomen lengths and males having larger heads and longer legs. Female common lizards start to reproduce at a relatively large size compared to most other populations. This is consistent with a relatively short activity season, which has been shown to be the main factor driving variation in body size in the common lizard. Clutch size was also relatively high and positively correlated with body size, abdomen size and head size. One third of all females attaining the size of the smallest gravid female showed no signs of reproductive activity despite mating opportunities, suggesting that not all females reproduce annually in this population.

  20. Ternary and Multi-Bit FIR Filter Area-Performance Tradeoffs in FPGA

    Directory of Open Access Journals (Sweden)

    Khalil-Ur-Rahman Dayo

    2013-01-01

    Full Text Available In this paper, performance and area of conventional FIR (Finite Impulse Responce filters versus ternary sigma delta modulated FIR filter is compared in FPGA (Field Programmable Gate Arrays using VHDL (Verilog Description Language. Two different approaches were designed and synthesized at same spectral performance by obtaining a TIR (Target Impulse Response. Both filters were synthesized on adaptive LUT (Look Up Table FPGA device in pipelined and non-pipelined modes. It is shown that the Ternary FIR filter occupies approximately the same area as the corresponding multi-bit filter, but for a given specification, the ternary FIR filter has 32% better performance in non-pipelined and 72% in pipelined mode, compared to its equivalent Multi-Bit filter at its optimum 12-bit coefficient quantization. These promising results shows that ternary logic based (i.e. +1,0,-1 filters can be used for huge chip area savings and higher performance.

  1. FIR Detectors/Cameras Based on GaN and Si Field-Effect Devices Project

    Data.gov (United States)

    National Aeronautics and Space Administration — SETI proposes to develop GaN and Si based multicolor FIR/THz cameras with detector elements and readout, signal processing electronics integrated on a single chip....

  2. Balsam Woolly Adelgid Survey on Balsam Fir Stand in Central Tract 2002

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — On August 14, 2002, Emily Grafton and Dawn Washington surveyed the balsam fir stand in the central tract, off of Delta 13 trail, near the Little Blackwater and Glade...

  3. Long-term changes in structure and composition following hurricanes in a primary lower montane rain forest in Puerto Rico

    Science.gov (United States)

    P.L. Weaver

    2013-01-01

    Ridges within the lower montane rain forests (sensu Beard) of the Caribbean Basin are dominated by Dacryodes excelsa, a tree species known as tabonuco in Puerto Rico and gommier in the Lesser Antilles. Periodially, hurricanes traverse the islands causing changes in structure, species composition, and dynamics of forests. The chronology of post-hurricane vegetation...

  4. Increases in mean annual temperature do not alter soil bacterial community structure in tropical montane wet forests

    Science.gov (United States)

    Paul C. Selmants; Karen L. Adair; Creighton M. Litton; Christian P. Giardina; Egbert Schwartz

    2016-01-01

    Soil bacteria play a key role in regulating terrestrial biogeochemical cycling and greenhouse gas fluxes across the soil-atmosphere continuum. Despite their importance to ecosystem functioning, we lack a general understanding of how bacterial communities respond to climate change, especially in relatively understudied ecosystems like tropical montane wet...

  5. Diversity and distribution of the bryophyte flora in montane forests in the Chapada Diamantina region of Brazil

    Directory of Open Access Journals (Sweden)

    Emilia de Brito Valente

    2013-09-01

    Full Text Available Bryophytes constitute an important component of tropical rain forests, which provide microhabitats favorable for their establishment. Bryophytes are also quite responsive to changes in microclimate, which makes them good bioindicators. This study aimed to determine the diversity and distribution of bryophytes in upper and lower montane forests of the Chapada Diamantina region of the state of Bahia, Brazil. To that end, we studied community aspects such as richness, diversity, substrates colonized, life forms and floristic similarity between areas and regions. In 2007 and 2008, we collected specimens from six forest sites, located from the north to the south of the Chapada Diamantina region. We identified a total of 205 infrageneric taxa. In comparison with the lower montane forests, the upper montane forests presented higher diversity and species richness, as well as greater numbers of substrates colonized, life form types, species of restricted geographic distribution and species typical of shaded areas. We also found low similarity in the species composition, the populations of the upper and lower montane forests forming two large and distinct groups. Although presenting relatively high floristic homogeneity among themselves, the Chapada Diamantina areas presented little similarity with those of the Atlantic Forest. This can be explained by the differences between the two regions in terms of environmental conditions, precipitation, seasonality, elevation and continentality.

  6. Dawn chorus variation in East-Asian tropical montane forest birds and its ecological and morphological correlates

    NARCIS (Netherlands)

    Chen, W.-M.; Lee, Y.-F.; Tsai, C.-F.; Yao, C.-T.; Chen, Y.-H.; Li, S.-H.; Kuo, Y.-M.

    2015-01-01

    Many birds in breeding seasons engage in vigorous dawn singing that often turns to a prominent chorus. We examined dawn chorus variation of avian assemblages in a tropical montane forest in Taiwan and tested the hypothesis that onset sequence is affected by eye sizes, foraging heights, and diet of b

  7. Changes in forest structure and composition after fire in tropical montane cloud forests near the Andean treeline

    NARCIS (Netherlands)

    Oliveras Menor, I.; Malhi, Y.; Salinas, N.; Huaman, V.; Urquiaga-Flores, E.; Kala-Mamani, J.; Quintano-Loaiza, J.A.; Cuba-Torres, I.; Lizarraga-Morales, N.; Roman-Cuesta, R.M.

    2014-01-01

    Background: In tropical montane cloud forests (TMCFs) fires can be a frequent source of disturbance near the treeline. Aims: To identify how forest structure and tree species composition change in response to fire and to identify fire-tolerant species, and determine which traits or characteristics a

  8. Plant species distribution in relation to water-table depth and soil redox potential in montane riparian meadows

    Science.gov (United States)

    Kathleen A. Dwire; J. Boone Kauffman; John E. Baham

    2006-01-01

    The distribution of riparian plant species is largely driven by hydrologic and soil variables, and riparian plant communities frequently occur in relatively distinct zones along streamside elevational and soil textural gradients. In two montane meadows in northeast Oregon, USA, we examined plant species distribution in three riparian plant communities¡ªdefined as wet,...

  9. Root nodulation in the wetland tree Pterocarpus officinalis along coastal and montane systems of Northeast of Puerto Rico

    Science.gov (United States)

    Rachel Pérez; Tamara Heartsill Scalley

    2008-01-01

    In Puerto Rico, brackish water wetlands were dominated by Pterocarpus officinalis previous to extensive deforestation due to agriculture. Today remnant wetlands are limited to small areas that are threatened by rise in sea level. We examined the root nodules of P. officinalis in montane and coastal sites and at 0, 10, 20 cm from the surface to determine if site...

  10. Wormmos (Pseudocalliergon trifarium) in trilveen in De Wieden: een arctisch-boreaal-montane mossoort, nieuw voor de Benelux

    NARCIS (Netherlands)

    Weeda, E.J.

    2006-01-01

    Zeer goed onderzochte gebieden blijven verrassingen bieden. Zo is Noordwest- Overijssel is bryologisch grondig onderzocht. Toch kon hier op 20 juni 2006 een nieuwe mossoort voor de Nederlandse flora worden buitgemaakt, en nog wel één met een arctisch-boreaal-montane verspreiding

  11. Analyzing cloud base at local and regional scales to understand tropical montane cloud forest vulnerability to climate change

    Science.gov (United States)

    Ashley E. Van Beusekom; Grizelle Gonzalez; Martha A. Scholl

    2017-01-01

    The degree to which cloud immersion provides water in addition to rainfall, suppresses transpiration, and sustains tropical montane cloud forests (TMCFs) during rainless periods is not well understood. Climate and land use changes represent a threat to these forests if cloud base altitude rises as a result of regional warming or deforestation. To establish a baseline...

  12. Long-term fragmentation effects on the distribution and dynamics of canopy gaps in a tropical montane forest

    Science.gov (United States)

    Nicholas R. Vaughn; Gregory P. Asner; Christian P. Giardina

    2015-01-01

    Fragmentation alters forest canopy structure through various mechanisms, which in turn drive subsequent changes to biogeochemical processes and biological diversity. Using repeated airborne LiDAR (Light Detection and Ranging) mappings, we investigated the size distribution and dynamics of forest canopy gaps across a topical montane forest landscape in Hawaii naturally...

  13. Changes in forest structure and composition after fire in tropical montane cloud forests near the Andean treeline

    NARCIS (Netherlands)

    Oliveras Menor, I.; Malhi, Y.; Salinas, N.; Huaman, V.; Urquiaga-Flores, E.; Kala-Mamani, J.; Quintano-Loaiza, J.A.; Cuba-Torres, I.; Lizarraga-Morales, N.; Roman-Cuesta, R.M.

    2014-01-01

    Background: In tropical montane cloud forests (TMCFs) fires can be a frequent source of disturbance near the treeline. Aims: To identify how forest structure and tree species composition change in response to fire and to identify fire-tolerant species, and determine which traits or characteristics

  14. Tree shaking machine aids cone collection in a Douglas-fir seed orchard.

    Science.gov (United States)

    Donald L. Copes; William K. Randall

    1983-01-01

    A boom-type tree shaker was used in a Douglas-fir seed orchard to remove cones from 7- to 9-meter tall grafted Douglas-fir trees. An average of 55 percent of the cones were removed by shaking, while damage inflicted to the upper crown was confined primarily to branch and leader breakage in the top three internodes. Damage to the lower bole, where the shaker head...

  15. Interferometric Mapping of Magnetic Fields in Star-forming Regions II. NGC2024 FIR5

    CERN Document Server

    Lai, S P; Girart, J M; Rao, R; Lai, Shih-Ping; Crutcher, Richard M.; Girart, Jose M.; Rao, Ramprasad

    2001-01-01

    We present the first interferometric polarization maps of the NGC2024 FIR5 molecular core obtained with the BIMA array at approximately 2 arcsec resolution. We measure an average position angle of -60+-6 degrees in the main core of FIR5 and 54+-9 degrees in the eastern wing of FIR5. The morphology of the polarization angles in the main core of FIR5 suggests that the field lines are parabolic with a symmetry axis approximately parallel to the major axis of the putative disk in FIR5, which is consistent with the theoretical scenario that the gravitational collapse pulled the field lines into an hour-glass shape. The polarization percentage decreases toward regions with high intensity and close to the center of the core, suggesting that the dust alignment efficiency may decrease at high density. The plane-of-sky field strength can be estimated with the modified Chandrasekhar-Fermi formula, and the small dispersion of the polarization angles in FIR5 suggests that the magnetic field is strong ($\\gtrsim$ 2mG) and p...

  16. Identification of varieties and gene flow in Douglas fir exemplified in artificially established stands in Germany

    Directory of Open Access Journals (Sweden)

    Barbara Fussi

    2013-12-01

    Full Text Available Douglas-fir [Pseudotsuga menziesii (Mirb. Franco] is an economically valuable non-native tree species in Germany and is considered very promising in view of global climate change. Therefore, the genetic characterization of Douglas-fir populations and seed stands in Germany is essential. We studied coastal and interior Douglas-fir varieties, both present in Germany, by using eleven isoenzyme and four microsatellite loci. By analyzing eight reference populations of known origin we were able to identify the two varieties on the population level using Bayesian and distance based methods. Seven populations present in Bavaria were then successfully assigned to one of the two varieties. Within varieties we found stronger grouping within the interior variety than within the coastal one. Despite lower differences within coastal Douglas-fir we have first indications for the origin of two populations. For two Bavarian populations, natural regeneration was included and genetic data revealed no significant genetic difference between adults and offspring. The parentage analysis for one of the studied stands revealed that a large proportion of adults took part in the reproduction, but some trees were more successful than others in transferring their genes to the next generation. Our study was able to improve variety identification of Douglas-fir using isoenzyme markers and nuclear microsatellites and study reproductive patterns, both are important issues for the management of Douglas-fir stands in Bavaria.

  17. Identification of varieties and gene flow in Douglas fir exemplified in artificially established stands in Germany

    Directory of Open Access Journals (Sweden)

    Barbara Fussi

    2013-12-01

    Full Text Available Douglas-fir [Pseudotsuga menziesii (Mirb. Franco] is an economically valuable non-native tree species in Germany and is considered very promising in view of global climate change. Therefore, the genetic characterization of Douglas-fir populations and seed stands in Germany is essential. We studied coastal and interior Douglas-fir varieties, both present in Germany, by using eleven isoenzyme and four microsatellite loci. By analyzing eight reference populations of known origin we were able to identify the two varieties on the population level using Bayesian and distance based methods. Seven populations present in Bavaria were then successfully assigned to one of the two varieties. Within varieties we found stronger grouping within the interior variety than within the coastal one. Despite lower differences within coastal Douglas-fir we have first indications for the origin of two populations. For two Bavarian populations, natural regeneration was included and genetic data revealed no significant genetic difference between adults and offspring. The parentage analysis for one of the studied stands revealed that a large proportion of adults took part in the reproduction, but some trees were more successful than others in transferring their genes to the next generation. Our study was able to improve variety identification of Douglas-fir using isoenzyme markers and nuclear microsatellites and study reproductive patterns, both are important issues for the management of Douglas-fir stands in Bavaria.

  18. Optimal design study of high order FIR digital filters based on neural network algorithm

    Institute of Scientific and Technical Information of China (English)

    王小华; 何怡刚

    2004-01-01

    An optimal design approach of high order FIR digital filter is developed based on the algorithm of neural networks with cosine basis function . The main idea is to minimize the sum of the square errors between the amplitude response of the desired FIR filter and that of the designed by training the weights of neural networks, then obtains the impulse response of FIR digital filter . The convergence theorem of the neural networks algorithm is presented and proved,and the optimal design method is introduced by designing four kinds of FIR digital filters , i.e., low-pass, high-pass,bandpass , and band-stop FIR digital filter. The results of the amplitude responses show that attenuation in stop-bands is more than 60 dB with no ripple and pulse existing in pass-bands, and cutoff frequency of passband and stop-band is easily controlled precisely . The presented optimal design approach of high order FIR digital filter is significantly effective.

  19. Radio Observations of the Star Formation Activities in the NGC 2024 FIR 4 Region

    CERN Document Server

    Choi, Minho; Lee, Jeong-Eun

    2015-01-01

    Star formation activities in the NGC 2024 FIR 4 region were studied by imaging centimeter continuum sources and water maser sources using several archival data sets from the Very Large Array. The continuum source VLA 9 is elongated in the northwest-southeast direction, consistent with the FIR 4 bipolar outflow axis, and has a flat spectrum in the 6.2-3.6 cm interval. The three water maser spots associated with FIR 4 are also distributed along the outflow axis. One of the spots is located close to VLA 9, and another one is close to an X-ray source. Examinations of the positions of compact objects in this region suggest that the FIR 4 cloud core contains a single low-mass protostar. VLA 9 is the best indicator of the protostellar position. VLA 9 may be a radio thermal jet driven by this protostar, and it is unlikely that FIR 4 contains a high-mass young stellar object (YSO). A methanol 6.7 GHz maser source is located close to VLA 9, at a distance of about 100 AU. The FIR 4 protostar must be responsible for the ...

  20. Atmospheric organic and inorganic nitrogen inputs to coastal urban and montane Atlantic Forest sites in southeastern Brazil

    Science.gov (United States)

    de Souza, Patricia A.; Ponette-González, Alexandra G.; de Mello, William Z.; Weathers, Kathleen C.; Santos, Isimar A.

    2015-06-01

    Tropical regions are currently experiencing changes in the quantity and form of nitrogen (N) deposition as a result of urban and industrial emissions. We quantified atmospheric N inputs to two coastal urban and two montane (400 m and 1000 m) Atlantic Forest sites downwind of the Metropolitan Region of Rio de Janeiro (MRRJ), Brazil, from August 2008 to August 2009. Concentrations of total dissolved nitrogen (TDN), dissolved inorganic nitrogen (DIN) and urea were measured in bulk precipitation at all sites, as well as in canopy throughfall in the lower montane forest. Dissolved organic nitrogen (DON) was calculated as the difference between TDN and DIN (NH4+ + NO3- + NO2-). Annual volume-weighted mean bulk concentrations of all N species were higher at the coastal urban than montane forest sites, with DON accounting for 32-56% and 26-32%, respectively, of the TDN concentration in bulk precipitation. Bulk deposition of TDN ranged 12.1-17.2 kg N ha- 1 yr- 1 and tended to decrease with increasing distance from the coastal urban region. In the lower montane forest, throughfall TDN flux, 34.3 kg N ha- 1 yr- 1, was over 2-fold higher than bulk TDN deposition, and DON comprised 57% of the total N deposited by throughfall to the forest soil. Urea comprised 27% of DON in throughfall compared to up to 100% in bulk precipitation. Our findings show that DON is an important, yet understudied, component of TDN deposition in tropical forest regions, comprising one-third to greater than one-half of the N deposited in rainfall and throughfall. Further, in this lower montane Atlantic Forest site, throughfall DIN flux was 1.5-3 fold higher than the suggested empirical critical load for humid tropical forests, highlighting the potential for increasing N pollution emitted from the MRRJ to impact N cycling in adjacent ecosystems.

  1. Carbon budget of Nyungwe Tropical Montane Rain Forest in Central Africa

    Science.gov (United States)

    Nyirambangutse, B.; Zibera, E.; Uwizeye, F. K.; Hansson, L.; Nsabimana, D.; Pleijel, H.; Uddling, J.; Wallin, G.

    2015-12-01

    African tropical rainforests host rich biodiversity and play many roles at different scales such as local, regional and global, in the functioning of the earth system. Despite that the African tropical forests are the world's second largest, it has been neglected in terms of understanding the storage and fluxes of carbon and other nutrients. The question of whether this biome is a net sink or source of atmospheric CO2 is still not answered, and little is known concerning the climate change response. Tropical montane forests are even more poorly sampled compared with their importance. Deeper understanding of these ecosystems is required to provide insights on how they might react under global change. To answer questions related to these issues for African tropical montane forests, 15 permanent 0.5 ha plots were established in 2011 in Nyungwe tropical montane rainforest gazetted as a National Park to protect its extensive floral and faunal diversity. The plots are arranged along an east-westerly transect and includes both primary and secondary forest communities. The study is connected to the global ecosystem monitoring network (GEM, http://gem.tropicalforests.ox.ac.uk/). The aim is to characterize spatial and temporal heterogeneity of carbon and nutrient dynamics processes. The role of microclimate, topography, human disturbances, and plant species to the variability of these pools and processes will be explored. We compare stocks and fluxes of carbon and nutrients of the secondary and primary forest communities. The carbon stock are determined by an inventory of height and diameter at breast height (dbh) of all trees with a dbh above 5 cm, wood density, biomass of understory vegetation, leaf area index, standing and fallen dead wood, fine root biomass and organic content of various soil layers (litter, organic and mineral soil down to 45 cm depth). The carbon fluxes are determined by measurements of photosynthesis and respiration of leaves, above and below ground

  2. 常压逆流连续萃取褐煤蜡工艺初探%Tentative exploration about Atmospheric Pressure Countercurrent Continuous Extracting Montan Wax Process

    Institute of Scientific and Technical Information of China (English)

    崔东方

    2013-01-01

    概述了褐煤蜡的特性和应用,重点介绍了褐煤蜡连续萃取的工艺流程,旨在推动我国褐煤蜡产业的发展,期望我国褐煤蜡能够大规模生产,从而大幅度提高劳动生产率,提高市场竞争力。%This article summarizes features and applications of Montan Wax, and highlights process of continuous extraction of Montan Wax so as to promote development of Montan Wax industry in our country, at the same time, we also expect large-scale production of Montan Wax, so that increase productivity greatly and improve market competitiveness.

  3. Topographic and spatial controls of palm species distributions in a montane rain forest, southern Ecuador

    DEFF Research Database (Denmark)

    Svenning, J.-C.; Harlev, D.; Sørensen, M.M.

    2009-01-01

    The northern Andes harbour a flora that is as species-rich or even richer than the 18-times larger lowland Amazon basin. Gaining an understanding of how the high species richness of the Andean region is generated and maintained is therefore of particular interest. Environmental sorting due...... to elevational gradients in climate has been emphasized as a driver of vegetation distribution and plant community assembly in tropical mountain areas such as the Andes for two centuries, while alternative mechanisms have been little studied. Here, we investigated the importance of topography and spatial......). Mantel tests and indicator species analysis showed that both topography and spatial location imposed strong controls on palm species distributions at the study site. Our results suggest that species distributions in the studied montane forest landscape were partly determined by the species' habitat...

  4. Taraxacum officinale pollen depresses seed set of montane wildflowers through pollen allelopathy

    Directory of Open Access Journals (Sweden)

    Deirdre Loughnan

    2014-08-01

    Full Text Available Plant species that share pollinators can suffer from interspecific pollen deposition. Male reproductive success is inevitably reduced by the loss of pollen to flowers of another species. Female reproductive success can be affected by reduced stigmatic area or, more strongly, through allelopathic effects by which the admixture of some foreign pollen reduces seed or fruit set. We tested for allelopathic effects of Taraxacum officinale (Asteracaeae pollen on the seed set of montane wildflowers Erythronium grandiflorum (Liliaceae and Erysimum capitatum (Brassicaceae, by hand-pollinating plants with pollen mixtures. Taraxacum is a common invasive species, which produces allelopathic chemicals in its root and vegetative tissue, making it a likely candidate for pollen allelopathy. Flowers of both species produced fewer well-developed seeds when pollinated with pollen mixtures containing Taraxacum pollen. The pollen-allelopathic potential of weedy dandelion may add to its ability to disrupt communities that it invades.

  5. Species composition of the vegetation along the Sherichhu River, lower montane area of Eastern Bhutan

    Directory of Open Access Journals (Sweden)

    Tenzin Jamtsho

    2017-06-01

    Full Text Available An investigation of the riparian vegetation along the Sherichhu River, lower montane area of Eastern Bhutan was conducted from April to December 2015 to explore the plant communities in terms of species composition. A total number of 18 plots were placed within the remnant patches of the vegetation on either side of the river. In total, 172 species of vascular plant has been recorded. The cluster analysis suggested four types of plant communities in the study area viz., the MallotusDesmodium-Rhus shrubland and the Syzygium venosum woodland communities, which are located in V-shaped valleys and the Albizia-Flueggea woodland and Quercus glauca woodland communities located in U-shaped valleys. In broad-spectrum, the topographic features and environmental variables i.e. litter accumulation and flooding condition might also have some impact on the species composition of the plant communities of this vegetation.

  6. Evidence of a high density population of harvested leopards in a montane environment.

    Directory of Open Access Journals (Sweden)

    Julia N Chase Grey

    Full Text Available Populations of large carnivores can persist in mountainous environments following extensive land use change and the conversion of suitable habitat for agriculture and human habitation in lower lying areas of their range. The significance of these populations is poorly understood, however, and little attention has focussed on why certain mountainous areas can hold high densities of large carnivores and what the conservation implications of such populations might be. Here we use the leopard (Panthera pardus population in the western Soutpansberg Mountains, South Africa, as a model system and show that montane habitats can support high numbers of leopards. Spatially explicit capture-recapture (SECR analysis recorded the highest density of leopards reported outside of state-protected areas in sub-Saharan Africa. This density represents a temporally high local abundance of leopards and we explore the explanations for this alongside some of the potential conservation implications.

  7. Postdispersal removal and germination of seed dispersed by Cercopithecus nictitans in a West African Montane Forest.

    Science.gov (United States)

    Chapman, Hazel M; Goldson, Stephen L; Beck, Josie

    2010-01-01

    Factors that determine the effectiveness of primates as seed dispersers include (i) the microsite into which they deposit seed, (ii) secondary removal of seed by other taxa and (iii) the effect of gut passage and/or spitting on subsequent seed germination. This contribution evaluated these factors in the little studied putty-nosed monkey, Cercopithecus nictitans, in a Nigerian montane forest. Field experiments showed that C. nictitans has greatly increased in its importance as a disperser of medium-sized seed (>5 mm) because other large primates have been hunted to near extinction. C. nictitans disperses seed across habitats by spitting and defaecation. Rates of secondary seed removal were high for all seed species irrespective of the presence or absence of C. nictitans faecal matter, size or microsite variables. Gut passage enhanced germination relative to hand-cleaned seed, while spitting had either no effect or decreased the germination rate. Copyright 2010 S. Karger AG, Basel.

  8. Agaricomycetes in low land and montane Atlantic Rain Forest in Northeast Brazil

    Directory of Open Access Journals (Sweden)

    Tatiana Gibertoni

    2014-10-01

    Full Text Available The Atlantic Rain Forest represents a group of extra-amazonic forests, among which the coastal and montane (“brejos de altitude” are the most common in Northeast Brazil. Between 2011 and 2013, 110 field trips were performed in nine reserves in the domain of the Atlantic Rain Forest. Two thousand two hundred sixty three Agaricomycetes were collected and represented 271 species, among which several new species to science, new occurrences to the continent, country, region, biome and States were found. Besides recently collected material, 309 exsiccates of Agaricomycetes deposited in the Herbarium URM were revised and represented 38 species, among which several new occurrences to the region and States. The results indicate the importance of the constant inventories and also of revisions of material deposited in herbaria as tools to improve the knowledge about the Brazilian micota.

  9. VLSI IMPLEMENTATION OF FIR FILTER USING COMPUTATIONAL SHARING MULTIPLIER BASED ON HIGH SPEED CARRY SELECT ADDER

    Directory of Open Access Journals (Sweden)

    S. Karunakaran

    2012-01-01

    Full Text Available Recent advances in mobile computing and multimedia applications demand high-performance and low-power VLSI Digital Signal Processing (DSP systems. One of the most widely used operations in DSP is Finite-Impulse Response (FIR filtering. In the existing method FIR filter is designed using array multiplier, which is having higher delay and power dissipation. The proposed method presents a programmable digital Finite Impulse Response (FIR filter for high-performance applications. The architecture is based on a computational sharing multiplier which specifically doing add and shift operation and also targets computation re-use in vector-scalar products. CSHM multiplier can be implemented by Carry Select Adder which is a high speed adder. A Carry-Select Adder (CSA can be implemented by using single ripple carry adder and add-one circuits using the fast all-one finding circuit and low-delay multiplexers to reduce the area and accelerate the speed of CSA. An 8-tap programmable FIR filter was implemented in tanner EDA tool using CMOS 180nm technology based on the proposed CSHM technique. In which the number of transistor, power (mW and clock cycle (ns of the filter using array multiplier are 6000, 3.732 and 9 respectively. The FIR filter using CSHM in which the number of transistor, power (mW and clock cycle (ns are 23500, 2.627 and 4.5 respectively. By adopting the proposed method for the design of FIR filter, the delay is reduced to about 43.2% in comparison with the existing method. The CSHM scheme and circuit-level techniques helped to achieve high-performance FIR filtering operation.

  10. Release of terpenes from fir wood during its long-term use and in thermal treatment.

    Science.gov (United States)

    Kačík, František; Veľková, Veronika; Šmíra, Pavel; Nasswettrová, Andrea; Kačíková, Danica; Reinprecht, Ladislav

    2012-08-21

    Building structures made from fir wood are often attacked by wood-destroying insects for which the terpenes it contains serve as attractants. One of the possibilities for extending the lifetime of structures is to use older wood with a lower content of terpenes and/or thermally modified wood. The study evaluated the levels of terpenes in naturally aged fir wood (108, 146, 279, 287 and 390 years) and their decrease by thermal treatment (the temperature of 60 °C and 120 °C, treatment duration of 10 h). Terpenes were extracted from wood samples by hexane and analyzed by gas-chromatography mass-spectrometry (GC-MS). The results indicate that recent fir wood contained approximately 60 times more terpenes than the oldest wood (186:3.1 mg/kg). The thermal wood treatment speeded up the release of terpenes. The temperature of 60 °C caused a loss in terpenes in the recent fir wood by 62%, the temperature of 120 °C even by >99%. After the treatment at the temperature of 60 °C the recent fir wood had approximately the same quantity of terpenes as non-thermally treated 108 year old wood, i.e., approximately 60-70 mg/kg. After the thermal treatment at the temperature of 120 °C the quantity of terpenes dropped in the recent as well as the old fir wood to minimum quantities (0.7-1.1 mg/kg). The thermal treatment can thus be used as a suitable method for the protection of fir wood from wood-destroying insects.

  11. Invasion of Gleditsia triacanthos in Lithraea ternifolia Montane Forests of Central Argentina.

    Science.gov (United States)

    Marco; Páez

    2000-10-01

    / The aim of this work is to study the invasion system constituted by the alien species Gleditsia triacanthos and the native dominant Lithraea ternifolia in montane forests of central Argentina, considering life history and demographic traits of both the alien and the native species and different site conditions for population growth (good and bad sites). Matrix models are applied to project the consequences of differences in vital rates for population growth. Analyzing these models helps identify which life cycle transitions contributed most to population growth. Obtained population growth rates are considered to assess predicted rates of spread using the reaction-diffusion (R-D) model. G. triacanthos presents many of the life history traits that confer plants high potential for invasiveness: fast growth, clonal and sexual reproduction, short juvenile period, high seed production, and high seed germinability. These traits would ensure G. triacanthos invasive success and the displacement of the slow-growing, relatively less fecund native L. ternifolia. However, since disturbance and environmental heterogeneity complicate the invasibility pattern of G. triacanthos in these montane forests, the outcome of the invasion process is not straightforward as could be if only life history traits were considered.Great variation in demographic parameters was observed between populations of each species at good and bad sites. Though both good and bad sites signified increasing or at least stable populations for G. triacanthos, for L. ternifolia bad sites represented local extinction. Analyzing the results of matrices models helps design the optimal management for the conservation of L. ternifolia populations while preventing the invasion by G. triacanthos. The predicted asymptotic rate of spread for G. triacanthos at the good site was fourfold greater than the predicted one for L. ternifolia, although the difference was much smaller considering the bad site. The usefulness of

  12. Elevational Ranges of Montane Birds and Deforestation in the Western Andes of Colombia.

    Directory of Open Access Journals (Sweden)

    Natalia Ocampo-Peñuela

    Full Text Available Deforestation causes habitat loss, fragmentation, degradation, and can ultimately cause extinction of the remnant species. Tropical montane birds face these threats with the added natural vulnerability of narrower elevational ranges and higher specialization than lowland species. Recent studies assess the impact of present and future global climate change on species' ranges, but only a few of these evaluate the potentially confounding effect of lowland deforestation on species elevational distributions. In the Western Andes of Colombia, an important biodiversity hotspot, we evaluated the effects of deforestation on the elevational ranges of montane birds along altitudinal transects. Using point counts and mist-nets, we surveyed six altitudinal transects spanning 2200 to 2800 m. Three transects were forested from 2200 to 2800 m, and three were partially deforested with forest cover only above 2400 m. We compared abundance-weighted mean elevation, minimum elevation, and elevational range width. In addition to analysing the effect of deforestation on 134 species, we tested its impact within trophic guilds and habitat preference groups. Abundance-weighted mean and minimum elevations were not significantly different between forested and partially deforested transects. Range width was marginally different: as expected, ranges were larger in forested transects. Species in different trophic guilds and habitat preference categories showed different trends. These results suggest that deforestation may affect species' elevational ranges, even within the forest that remains. Climate change will likely exacerbate harmful impacts of deforestation on species' elevational distributions. Future conservation strategies need to account for this by protecting connected forest tracts across a wide range of elevations.

  13. DNA Barcoding of an Assembly of Montane Andean Butterflies (Satyrinae): Geographical Scale and Identification Performance.

    Science.gov (United States)

    Marín, M A; Cadavid, I C; Valdés, L; Álvarez, C F; Uribe, S I; Vila, R; Pyrcz, T W

    2017-01-23

    DNA barcoding is a technique used primarily for the documentation and identification of biological diversity based on mitochondrial DNA sequences. Butterflies have received particular attention in DNA barcoding studies, although varied performance may be obtained due to different scales of geographic sampling and speciation processes in various groups. The montane Andean Satyrinae constitutes a challenging study group for taxonomy. The group displays high richness, with more of 550 species, and remarkable morphological similarity among taxa, which renders their identification difficult. In the present study, we evaluated the effectiveness of DNA barcodes in the identification of montane Andean satyrines and the effect of increased geographical scale of sampling on identification performance. Mitochondrial sequences were obtained from 104 specimens of 39 species and 16 genera, collected in a forest remnant in the northwest Andes. DNA barcoding has proved to be a useful tool for the identification of the specimens, with a well-defined gap and producing clusters with unambiguous identifications for all the morphospecies in the study area. The expansion of the geographical scale with published data increased genetic distances within species and reduced those among species, but did not generally reduce the success of specimen identification. Only in Forsterinaria rustica (Butler, 1868), a taxon with high intraspecific variation, the barcode gap was lost and low support for monophyly was obtained. Likewise, expanded sampling resulted in a substantial increase in the intraspecific distance in Morpho sulkowskyi (Kollar, 1850); Panyapedaliodes drymaea (Hewitson, 1858); Lymanopoda obsoleta (Westwood, 1851); and Lymanopoda labda Hewitson, 1861; but for these species, the barcode gap was maintained. These divergent lineages are nonetheless worth a detailed study of external and genitalic morphology variation, as well as ecological features, in order to determine the potential

  14. Detecting Montane Meadows in the Tahoe National Forest Using LiDAR and ASTER Imagery

    Science.gov (United States)

    Lorenz, A.; Blesius, L.; Davis, J. D.

    2016-12-01

    In the Sierra Nevada mountains, meadows provide numerous hydraulic and ecosystem functions such as flood attenuation, groundwater storage, and wildlife habitat. However, many meadows have been degraded from historical land use such as water diversion, grazing, and logging. Land managers have altered management strategies for restoration purposes, but there is a lack of comprehensive data on meadow locations. Previous attempts to inventory Sierra Nevada meadows have included several remote sensing techniques including heads up digitizing and pixel based image analysis, but this has been challenging due to geographic variability, seasonal changes, and meadow health. I present a remote sensing method using multiple return LiDAR (Light Detection and Ranging) and ASTER imagery to detect montane meadows in a subset of the Tahoe National Forest. The project used LiDAR data to create a digital terrain model and digital surface model. From these models, I derived canopy height, surface slope, and watercourse for the entire study area. Literature queries returned known values for canopy height and surface slope characteristic of montane meadows. These values were used to select for possible meadows within the study area. To filter out noise, only contiguous areas greater than one acre that satisfied the queries were used. Finally, 15-meter ASTER imagery was used to de-select for areas such as dirt patches or gravel bars that might have satisfied the previous queries and meadow criteria. When using high resolution aerial imagery to assess model accuracy, preliminary results show user accuracy of greater than 80%. Further validation is still needed to improve the accuracy of modeled meadow delineation. This method allows for meadows to be inventoried without discriminating based on geographic variability, seasonal changes, or meadow health.

  15. Demographic responses of boreal-montane orchid Malaxis monophyllos (L. Sw. populations to contrasting environmental conditions

    Directory of Open Access Journals (Sweden)

    Edyta Jermakowicz

    2016-03-01

    Full Text Available In an age of changes in species’ geographical ranges, compounded by climatic and anthropogenic impacts, it become important to know which processes and factors influence plant populations and their persistence in the long term. Here we investigated dynamic and fitness components in twelve populations of Malaxis monophyllos (L. Sw., situated in different geographical (regions and ecological (type of habitat units. Although M. monophyllos is a rare species, characterized by highly fragmented, boreal-montane distribution range, in last few decades it successfully colonized secondary habitats in Polish uplands. Our results indicate that M. monophyllos is represented mainly by small populations, which annual spatial and temporal changes might be very high, what affects the ephemeral character of these populations, regardless of the region and type of habitat. This dynamic structure, in turn, is caused by intensive exchange of individuals in populations, as well as by their short above-ground life span. Despite the large range of variation in size and reproductive traits, we can distinguish some regional patterns, which indicate boreal region as the most optimal for M. monophyllos growth and persistence in the long term, and with montane and upland/anthropogenic populations, due to lower reproductive parameters, as the most threatened. Although it should be considered that anthropogenic populations, despite their lower reproductive parameters and instability in the long term, present an intermediate, geographical and ecological character, therefore they may be valuable in shaping, both M. monophyllos’ future range, as well as its potential for response on ongoing and future changes. In general, reproduction is the main factor differentiating of M. monophyllos populations in regions, and we can suspect that it may become the cause of the future differentiation and isolation of these populations, occurring with progressive range fragmentation.

  16. Elevational Ranges of Montane Birds and Deforestation in the Western Andes of Colombia.

    Science.gov (United States)

    Ocampo-Peñuela, Natalia; Pimm, Stuart L

    2015-01-01

    Deforestation causes habitat loss, fragmentation, degradation, and can ultimately cause extinction of the remnant species. Tropical montane birds face these threats with the added natural vulnerability of narrower elevational ranges and higher specialization than lowland species. Recent studies assess the impact of present and future global climate change on species' ranges, but only a few of these evaluate the potentially confounding effect of lowland deforestation on species elevational distributions. In the Western Andes of Colombia, an important biodiversity hotspot, we evaluated the effects of deforestation on the elevational ranges of montane birds along altitudinal transects. Using point counts and mist-nets, we surveyed six altitudinal transects spanning 2200 to 2800 m. Three transects were forested from 2200 to 2800 m, and three were partially deforested with forest cover only above 2400 m. We compared abundance-weighted mean elevation, minimum elevation, and elevational range width. In addition to analysing the effect of deforestation on 134 species, we tested its impact within trophic guilds and habitat preference groups. Abundance-weighted mean and minimum elevations were not significantly different between forested and partially deforested transects. Range width was marginally different: as expected, ranges were larger in forested transects. Species in different trophic guilds and habitat preference categories showed different trends. These results suggest that deforestation may affect species' elevational ranges, even within the forest that remains. Climate change will likely exacerbate harmful impacts of deforestation on species' elevational distributions. Future conservation strategies need to account for this by protecting connected forest tracts across a wide range of elevations.

  17. Subspecific Differentiation Events of Montane Stag Beetles (Coleoptera, Lucanidae) Endemic to Formosa Island.

    Science.gov (United States)

    Tsai, Cheng-Lung; Yeh, Wen-Bin

    2016-01-01

    Taxonomic debates have been carrying on for decades over Formosan stag beetles, which consist of a high proportion of endemic species and subspecies featuring morphological variations associated with local adaptation. With the influence of periodical Pleistocene glaciations and the presence of several mountain ranges, the genetic differentiation and taxonomic recognition, within this medium-size island, of two endemic subspecies for each of four montane stag beetles, i.e. Lucanus ogakii, L. kanoi, Prismognathus davidis, and Neolucanus doro, has been an appealing issue. Based on monophyletic lineages and population structure, possible divergent scenarios have been proposed to clarify the subspecific status for each of the above mentioned stag beetles. Phylogenetic inferences based on COI+16S rDNA+28S rDNA of 240 Formosan lucanids have confirmed most species are monophyletic groups; and the intraspecific (2%) genetic distances of the two mitochondrial genes could be applied concordantly for taxonomic identification. On account of Bayesian-based species delimitation, geographic distribution, population structure, and sequence divergences, the subspecific status for L. ogakii, L. kanoi, and Pri. davidis are congruent with their geographic distribution in this island; and the calibration time based on the mitochondrial genes shows the subspecific split events occurred 0.7-1 million years ago. In addition, a more complicated scenario, i.e. genetic differentiation including introgression/hybridization events, might have occurred among L. ogakii, L. kanoi, and L. maculifemoratus. The geological effects of mountain hindrance accompanied by periodical glaciations could have been vital in leading to the geographical subspecific differentiation of these montane stag beetles.

  18. Modeling the gopher-meadow eco-geomorphic system on montane hillslopes

    Science.gov (United States)

    Winchell, E. W.; Doak, D. F.; Anderson, R. S.

    2013-12-01

    On montane hillslopes of Colorado's Front Range, the transport of soil by gophers can dominate the modern geomorphic system in meadows. Qualitative observations reveal that gophers prefer to forage in meadows over forests, that seedling roots are consumed by gophers, and that trees commonly occupy the rocky crests of hills overlooking open meadow hillslopes. This motivates a numerical model of gopher-mediated transport of soil and the long-term evolution of the coupled ecological-geomorphic system through quantitative observations from a manipulative experiment on meadow-centered plots in the Boulder Creek CZO in the Colorado Front Range montane forest. The ecological and geomorphic processes in the coupled system we wish to model must include: seedling establishment and damage, gopher tunneling geometries and resulting mound generation, mound material transport driven by rain and hail and by ungulate trampling, vegetative lock-down of mound material, and resulting changes in the soil depth and rockiness of the landscape. We must therefore have algorithms to capture the feedback mechanisms between gopher activity and the growth and potential death of trees, the casting of seeds and their likelihood of germination, and the spatial distribution of plants. The ecological component interacts with the soils/critical zone layer through feedbacks that include the dependence of gopher activity on root density, depth, and size, undergrowth availability, and the dependence of the rate of change of soil thickness on gradients in gopher-mediated transport. Results of a preliminary cellular automaton model which captures the essence of these geomorphic-ecological feedbacks can readily address the role of gophers in limiting the encroachment of trees into meadow patches. The bioturbation of the meadows, and the downslope transport of soil within them, is much more efficient than that in the forest, which sees little to no gopher activity. These geomorphic transport hotspots will

  19. Fast Adaptive Blind MMSE Equalizer for Multichannel FIR Systems

    Directory of Open Access Journals (Sweden)

    Abed-Meraim Karim

    2006-01-01

    Full Text Available We propose a new blind minimum mean square error (MMSE equalization algorithm of noisy multichannel finite impulse response (FIR systems, that relies only on second-order statistics. The proposed algorithm offers two important advantages: a low computational complexity and a relative robustness against channel order overestimation errors. Exploiting the fact that the columns of the equalizer matrix filter belong both to the signal subspace and to the kernel of truncated data covariance matrix, the proposed algorithm achieves blindly a direct estimation of the zero-delay MMSE equalizer parameters. We develop a two-step procedure to further improve the performance gain and control the equalization delay. An efficient fast adaptive implementation of our equalizer, based on the projection approximation and the shift invariance property of temporal data covariance matrix, is proposed for reducing the computational complexity from to , where is the number of emitted signals, the data vector length, and the dimension of the signal subspace. We then derive a statistical performance analysis to compare the equalization performance with that of the optimal MMSE equalizer. Finally, simulation results are provided to illustrate the effectiveness of the proposed blind equalization algorithm.

  20. Creep of Chinese Fir Wood Treated by Different Reagents

    Institute of Scientific and Technical Information of China (English)

    Xue Feng-lian; Zhao Guang-jie; Lü Wen-hua

    2005-01-01

    In order to investigate the effect of different reagents on changes of the crystalline region and amorphous region(Matrix) in wood cell walls, the creep behavior of Chinese fir (Cunninghamia lanceolata) wood treated with dimethyl sulfoxide(DMSO) and diethyl amine, sulfur dioxide and dimethyl sulfoxide mixture (DEA-SO2-DMSO), and the untreated wood at oven-dried,air-dry and water-saturated states during adsorption and desorption processes were all examined in air or in water. The measurements were carried out at ambient temperature and atmospheric pressure. The load is constant with 62 g or 0.607 6 N. The results obtained were as follows: 1) The instantaneous compliance Jo and the creep compliance J of specimens decrystallized with DEA-SO2-DMSO solution were bigger than those of DMSO swollen wood, and the latter was still much bigger than those of untreated wood. 2) For untreated wood, Jo and J increased with equilibrium moisture content (EMC) of wood, but there was not apparent correlation between wood EMC and the relative compliance. 3) Specimens treated with DMSO and DEA-SO2-DMSO mixture were recrystallized after immersion in water, and the degree of recrystallization of the former was larger. 4) For oven-dried specimens, the creep compliances in water were bigger than those in air. But for fiber-saturated and water-saturated specimens they were nearly equivalent to each other.

  1. FIR line profiles as probes of warm gas dynamics

    Science.gov (United States)

    Betz, A. L.; Boreiko, R. T.

    1995-01-01

    Measurements of the shapes, velocities, and intensities of FIR lines all help to probe the dynamics, physical associations, and excitation conditions of warm gas in molecular clouds. With this in mind, we have observed the J=9-8, 12-11,14-13, and 16-15 lines of (12)CO and the 158 micron line of C II in a number of positions in 4 selected clouds. The data were obtained with a laser heterodyne spectrometer aboard NASA's Kuiper Airborne Observatory. Line measurements at 0.6 km/s resolution allow us to resolve the profiles completely, and thereby to distinguish between UV-and shock-heating mechanisms for the high-excitation gas. For CO, the high-J linewidths lie in the range of 4-20 km/s (FWHM), similar to those observed for low-J (J less than 4) transitions in these sources. This correspondence suggests that the hotter gas (T = 200-600 K) is dynamically linked to the quiescent gas component, perhaps by association with the UV-heated peripheries of the numerous cloud clumps. Much of the C II emission is thought to emanate from these cloud peripheries, but the line profiles generally do not match those seen in CO. None of the observed sources show any evidence in high-J (12)CO emission for shock-excitation (i.e., linewidths greater than 30 km/s).

  2. Potential programs for high sensitivity FIR spectroscopy with SPICA

    CERN Document Server

    Spinoglio, L; Saraceno, P; Spinoglio, Luigi; Giorgio, Anna Maria Di; Saraceno, Paolo

    2006-01-01

    We discuss the potential of high sensitivity mid-IR and far-IR spectroscopy to proof the physical properties of active nuclei and starburst regions of local and distant galaxies. For local galaxies, it will be possible to map the discs and ISM through the low ionization ionic lines and a variety of molecular tracers, such as OH, H2O and high-J CO. At increasing distance, most of the ionic nebular lines (typical of stars and AGNs) are shifted into the FIR, making possible to compare the observed spectra with those predicted by different evolutionary scenarios. At the very high redshift of 10-15, sensitive mid-to-far-IR spectrometers, such as those planned to be at the focal plane of the future SPICA mision, could be adequate to detect the H recombination lines excited in the HII regions around population III stars, if these stars happened to reside in large clusters of more than 10^5 members.

  3. COLOR CHANGE OF CHINESE FIR THROUGH STEAM-HEAT TREATMENT

    Directory of Open Access Journals (Sweden)

    Yongjian Cao,

    2012-05-01

    Full Text Available Dark brown wood color is a current trend and widely appreciated by consumers in the furniture and decoration markets. Heat treatment is one of the most effective methods to darken wood’s appearance. The influence of steam-heat treatment on color change of Chinese fir (Cunninghamia lanceolata (Lamb. Hook. was investigated within the temperature range from 170 to 230 oC and time from 1 to 5 hours in an air-tight chamber within an atmosphere comprising less than 2 percent oxygen. Saturated steam was used as a heating medium and a shielding gas. The results showed that the chroma difference (△C* decreased gradually, while the color difference (△E* and hue difference (△H* increased with an increase in temperature and length of time. An analysis of variance (ANOVA and a multi-comparison analysis revealed that the treatment temperature plays a more important role in darkening wood color during the process of steam-heat treatment in comparison with the treatment time. The results suggest that a more desirable wood color can be achieved with the technology of steam-heat treatment.

  4. Response of birds to thinning young Douglas-fir forests

    Science.gov (United States)

    Hayes, John P.; Weikel, Jennifer M.; Huso, Manuela M. P.; Erickson, Janet L.

    2003-01-01

    As a result of recent fire history and decades of even-aged forest management, many coniferous forests in western Oregon are composed of young (20-50 yrs), densely stocked Douglas-fir stands. Often these stands are structurally simple - a single canopy layer with one or two overstory tree species - and have a relatively sparse understory. The lack of structural complexity in these stands may limit the availability of key habitat components for several species of vertebrates, including birds. Thinning may increase structural diversity by reducing competition among overstory trees and increasing the amount of sunlight reaching the forest floor, thereby increasing development of understory vegetation. Existing old-growth forests may have developed under lower densities than is typical of contemporary plantations. Thus, thinning also may be a tool for accelerating the development of late-successional forest conditions in some circumstances. In addition to the potential increases in structural and biological diversity, thinning frequently is used to optimize wood fiber production and to generate timber revenue.

  5. 1D and 2D economical FIR filters generated by Chebyshev polynomials of the first kind

    Science.gov (United States)

    Dragoljub Pavlović, Vlastimir; Stanojko Dončov, Nebojša; Gradimir Ćirić, Dejan

    2013-11-01

    Christoffel-Darboux formula for Chebyshev continual orthogonal polynomials of the first kind is proposed to find a mathematical solution of approximation problem of a one-dimensional (1D) filter function in the z domain. Such an approach allows for the generation of a linear phase selective 1D low-pass digital finite impulse response (FIR) filter function in compact explicit form by using an analytical method. A new difference equation and structure of corresponding linear phase 1D low-pass digital FIR filter are given here. As an example, one extremely economic 1D FIR filter (with four adders and without multipliers) is designed by the proposed technique and its characteristics are presented. Global Christoffel-Darboux formula for orthonormal Chebyshev polynomials of the first kind and for two independent variables for generating linear phase symmetric two-dimensional (2D) FIR digital filter functions in a compact explicit representative form, by using an analytical method, is proposed in this paper. The formula can be most directly applied for mathematically solving the approximation problem of a filter function of even and odd order. Examples of a new class of extremely economic linear phase symmetric selective 2D FIR digital filters obtained by the proposed approximation technique are presented.

  6. Characteristics of heat-treated Turkish pine and fir wood after ThermoWood processing.

    Science.gov (United States)

    Kol, Hamiyet Sahin

    2010-11-01

    The Finnish wood heat treatment technology ThermoWood, was recently introduced to Turkey. Data about the mechanical and physical properties of Turkish wood species are important for industry and academia. In this study two industrially important Turkish wood species, pine (Pinus nigraArnold.) and fir (Abies bornmülleriana Matf.) were heat-treated using the ThermoWood process. Pine and fir samples were thermally modified for 2 hr at 212 and 190 degrees C, respectively. The modulus of rupture (MOR), modulus of elasticity in bending (MOE), impact bending strength (IBS), and compression strength (CS), in addition to swelling (Sw) and shrinkage (Sh) of thermally-modified wood were examined. The results indicate that the heat treatment method clearly decreased the MOR, MOE and lBS of pine and fir. However, a small increase was observed for CS values of heat treated wood species. The most affected mechanical properties were MOR and lBS for both pine and fir. The reduction in MOE was smaller than that in MOR and lBS. Volumetric shrinkage and swelling of these species were also improved by approximately half. In Addition, the changes in the mechanical and physical properties studied in pine were larger than that of fir.

  7. Effects of Temperature on Photosynthetic Rates in Korean Fir (Abies koreana) between Healthy and Dieback Population

    Institute of Scientific and Technical Information of China (English)

    Su Young Woo; Jong-Hwan Lim; Don Koo Lee

    2008-01-01

    The present study was carried out on natural Korean fir forests (Abies koreana) growing In Mount Halla in Jeju Island, Korea (33°13-36′ N and 126° 12-57′ E). Mount Halla is the highest mountain (1950 m a.s.l.) in South Korea. On the Korean fir forests near the top of Mount Halla in Korea, we established permanent plots between dieback and healthy population. Each permanent plot includes both dieback and relatively healthy Korean fir individuals. Three sites in this study showed similar altitude, topographic position, aspects, slope, diameter at breast height, average height and ages. Net photosynthetic rates (PN) on different temperature regimes were evaluated to explain the forest dieback phenomenon on Korean fir populations. Light response curves were determined on three different temperature regimes: 15℃, 20℃and 25℃. The Irradiance response curve showed higher values in lower air temperatures. Generally, Irradiance response curves of healthy Korean fir populations were higher than the dieback population at all sites.

  8. Water status of bare—root seedlings of Chinese fir and Masson pine

    Institute of Scientific and Technical Information of China (English)

    YUFang-yuan; GUOXin-bao; XUXi-zeng

    2003-01-01

    Water relation parameters of bare-root seedlings of Chinese fir (Cunninghamia lanceolata Hook.)and Masson pine (Pinus massoniana Lamb.)were measured and changes of root growth potential as well as field survival rate of both species were studied after the bare-root seedlings were exposed in a sunny field condition.the results showed that masson pine had a lower osmotic potential(-2.07Mpa) at turgor loss point and at full turgor(-1.29Mpa),compared with Chinese fir(-1.80Mpa and -1.08Mpa respectively).The parameter Vp/Vo(63.27%) of Masson pine was higher than that of chinese fir (58.03%).This means that Masson pine has a stronger ability to tolerate desiccation,compared to Chinese fir according to analysis of above water relation parameters.Root growth potential and field survival rate decreased with prolonging duration of exposure.The field survival rate of both species was reduced to less than 40% after the seedling being exposed only two hours.Water potentials of -1.60 Mpa and -1.70 Mpa were suggested to be critical values for Chinese fir and Masson pine respectively in successful reforestation.

  9. Three new species of Pristimantis (Lissamphibia, Anura from montane forests of the Cordillera Yanachaga in Central Peru

    Directory of Open Access Journals (Sweden)

    William E. Duellman

    2007-12-01

    Full Text Available We describe three additional new species of Pristimantis from the Cordillera Yanachaga, a part of the Andes in central Peru. Analyses of DNA sequences of the mitochondrial rRNA genes show that onespecies is a close relative of P. bipunctatus (P. conspicillatus Group, another is a close relative of P. stictogaster (P. peruvianus Group, and the third is related to several species in the P. unistrigatus Group. The first two species are morphologically similar to their closest relatives but occur at lower elevations. Twenty-nine species of Pristimantis and Phrynopus are known from the vicinity of the Cordillera Yanachaga. The number of species, especially of Pristimantis, is high in the humid montane forestin comparison with other sites in humid montane forests in Peru, but the number is lower than on the western slopes of the Andes in Ecuador.

  10. Development-Induced Displacement in Romania: the Case of Roşia Montană Mining Project

    Directory of Open Access Journals (Sweden)

    Lucian VESALON

    2012-06-01

    Full Text Available This paper proposes a critical discussion of the population displacement processes involved in the Roşia Montană gold-mining project within the theoretical framework of development-induced displacement (DID. We begin with an overview of the geographical context of the rural community, focusing on the social and economic structure of Roşia Montană. After assessing the relocation and resettlement processes, we examine several problems related to the compensation mechanism set up by the mining company. The aim of the research is to highlight the complexity of the consequences of development-induced displacement and the limits of the policies of relocation and resettlement in the area.

  11. Assessing the effects of vegetation types on carbon storage fifteen years after reforestation on a Chinese fir site

    Science.gov (United States)

    Qinkui Wang; Silong Wang; Jianwei Zhang

    2009-01-01

    Forest ecosystems play a significant role in sequestering carbon (C) in biomass and soils. Plantations established in subtropical China since the 1980s, mainly of Chinese fir (Cunninghamia lanceolata (Lamb.) Hook) in monocultures, have proved to be major C sinks. However, information is lacking about whether mixing Chinese fir with broadleaved tree...

  12. Genetic variation and risks of introgression in the wild Coffea arabica gene pool in south-western Ethiopian montane rainforests

    OpenAIRE

    Aerts, Raf; Berecha, Gezahegn; Gijbels, Pieter; Hundera, Kitessa; Vandepitte,Katrien; Van Glabeke, Sabine; Muys, Bart; Roldan-Ruiz, Isabel; Honnay, Olivier

    2012-01-01

    The montane rainforests of SW Ethiopia are the primary centre of diversity of Coffea arabica and the origin of all Arabica coffee cultivated worldwide. This wild gene pool is potentially threatened by forest fragmentation and degradation, and by introgressive hybridisation with locally improved coffee varieties. We genotyped 703 coffee shrubs from unmanaged and managed coffee populations, using 24 microsatellite loci. Additionally, we genotyped 90 individuals representing 23 Ethiopian cult...

  13. "Fine-scale climatic variation drives altitudinal niche partitioning of tabanid flies in a tropical montane cloud forest, Ecuadorian Choco"

    OpenAIRE

    Cárdenas Muñoz, Rafael Enrique

    2015-01-01

    In montane systems, global warming may lead communities to disassemble by forcing organisms to shift their distributions to higher elevations or by causing the extinction of those that are unable to adapt. To predict which species are most at risk from environmental change, physiological responses to multiple factors must be measured in natural conditions at fine spatial and temporal scales. To examine the potential drivers of elevational distributions in tabanid flies, specimens were exha...

  14. Hemibeltrania urbanodendrii sp. nov. and Pseudobeltrania angamosensis: new fungal records from the brazilian tropical seasonal semi-deciduous montane forest

    OpenAIRE

    Ronaldo de Castro Fernandes; Denise Castro Lustosa; Robert Weingart Barreto; José Luiz Bezerra

    2007-01-01

    The new species Hemibeltrania urbanodendrii, associated to leaf-spots on Urbanodendron verrucosum (Lauracea) and Pseudobeltrania angamosensis, associated with leaf-spots on Virola gardneri (Myristicaceae), are recorded for the first time in Brazil. They represent additions to the mycobiota of the Tropical Seasonal Semi-Deciduous Montane Forest in Viçosa (Minas Gerais, Brazil), a highly threatened ecosystem.Novas ocorrências de fungos relacionados a manchas foliares são apresentadas: Hemibeltr...

  15. Scale-dependent effects of post-fire canopy cover on snowpack depth in montane coniferous forests.

    Science.gov (United States)

    Stevens, Jens T

    2017-09-01

    Winter snowpack in dry montane regions provides a valuable ecosystem service by storing water into the growing season. Wildfire in coniferous montane forests has the potential to indirectly affect snowpack accumulation and ablation (mass loss) rates by reducing canopy cover, which reduces canopy interception of snow but also increases solar radiation and wind speed. These counteracting effects create uncertainty regarding the canopy conditions that maximize post-fire snowpack duration, which is of concern as montane regions across the western United States experience increasingly warm, dry winters with below-average snowpack. The net effect of wildfire on snowpack depth and duration across the landscape is uncertain, and likely scale dependent. In this study, I tested whether intermediate levels of wildfire severity maximize snowpack depth by increasing accumulation while slowing ablation, using gridded, repeated snow depth measurements from three fires in the Sierra Nevada of California. Increasing fire severity had a strong negative effect on snowpack depth, suggesting that increased ablation after fire, rather than increased accumulation, was the dominant control over snowpack duration. Contrary to expectations, the unburned forest condition had the highest overall snowpack depth, and mean snow depth among all site visits was reduced by 78% from unburned forest to high-severity fire. However, at the individual tree scale, snowpack depth was greater under canopy openings than underneath canopy, controlling for effects of fire severity and aspect. This apparent paradox in snowpack response to fire at the stand vs. individual tree scales is likely due to greater variation in canopy cover within unburned and very low severity areas, which creates smaller areas for snow accumulation while reducing ablation via shading. Management efforts to maximize snowpack duration in montane forests should focus on retaining fine-scale heterogeneity in forest structure. © 2017 by

  16. Soil Fertility in Agroforestry System of Chinese Fir and Villous Amomum in Subtropical China

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A trial of interplanting and non-interplanting villous amomum (Amomum villosum Lour.) under the canopy of Chinese fir (Cunninghamia lanceolata Hook.) at age 22 was established in Sanming, Fujian of China, and a survey on soil fertility was carried out 10 years after its establishment. Compared with the control (non-interplanting), the properties of soil humus in agroforestry system were ameliorated, with a higher level of humification and resynthesis of organic detritus. The soil microbial population and enzymatic activities were both higher under the influence of villous amomum. Both the nutrient supplying and nutrient conserving capacities of the soil were improved. This agroforestry system exhibited an advantage of improved soil fertility, as well as an accelerated growth of Chinese fir, it was, therefore, a sustainable management system suited for Chinese fir in South China.

  17. Big Bang–Big Crunch Optimization Algorithm for Linear Phase Fir Digital Filter Design

    Directory of Open Access Journals (Sweden)

    Ms. Rashmi Singh Dr. H. K. Verma

    2012-02-01

    Full Text Available The Big Bang–Big Crunch (BB–BC optimization algorithm is a new optimization method that relies on the Big Bang and Big Crunch theory, one of the theories of the evolution of the universe. In this paper, a Big Bang–Big Crunch algorithm has been used here for the design of linear phase finite impulse response (FIR filters. Here the experimented fitness function based on the mean squared error between the actual and the ideal filter response. This paper presents the plot of magnitude response of FIR filters and error graph. The BB-BC seems to be promising tool for FIR filter design especially in a dynamic environment where filter coefficients have to be adapted and fast convergence is of importance.

  18. Morphological defects in native Japanese fir trees around the Fukushima Daiichi Nuclear Power Plant.

    Science.gov (United States)

    Watanabe, Yoshito; Ichikawa, San'ei; Kubota, Masahide; Hoshino, Junko; Kubota, Yoshihisa; Maruyama, Kouichi; Fuma, Shoichi; Kawaguchi, Isao; Yoschenko, Vasyl I; Yoshida, Satoshi

    2015-08-28

    After the accident at the Fukushima Daiichi Nuclear Power Plant (F1NPP) in March 2011, much attention has been paid to the biological consequences of the released radionuclides into the surrounding area. We investigated the morphological changes in Japanese fir, a Japanese endemic native conifer, at locations near the F1NPP. Japanese fir populations near the F1NPP showed a significantly increased number of morphological defects, involving deletions of leader shoots of the main axis, compared to a control population far from the F1NPP. The frequency of the defects corresponded to the radioactive contamination levels of the observation sites. A significant increase in deletions of the leader shoots became apparent in those that elongated after the spring of 2012, a year after the accident. These results suggest possibility that the contamination by radionuclides contributed to the morphological defects in Japanese fir trees in the area near the F1NPP.

  19. Frequency Spectrum Based Low-Area Low-Power Parallel FIR Filter Design

    Directory of Open Access Journals (Sweden)

    Jin-Gyun Chung

    2002-09-01

    Full Text Available Parallel (or block FIR digital filters can be used either for high-speed or low-power (with reduced supply voltage applications. Traditional parallel filter implementations cause linear increase in the hardware cost with respect to the block size. Recently, an efficient parallel FIR filter implementation technique requiring a less-than linear increase in the hardware cost was proposed. This paper makes two contributions. First, the filter spectrum characteristics are exploited to select the best fast filter structures. Second, a novel block filter quantization algorithm is introduced. Using filter benchmarks, it is shown that the use of the appropriate fast FIR filter structures and the proposed quantization scheme can result in reduction in the number of binary adders up to 20%.

  20. Design of Maximally Flat FIR Filters Based on Explicit Formulas Combined with Optimization

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A maximally flat FIR filter design method based on explicit formulas combined with simulated annealing and random search was presented. Utilizing the explicit formulas to calculate the initial values, the finite-word-length FIR filter design problem was converted into optimization of the filter coefficients. An optimization method combined with local discrete random search and simulated annealing was proposed, with the result of optimum solution in the sense of Chebyshev approximation. The proposed method can simplify the design process of FIR filter and reduce the calculation burden. The simulation result indicates that the proposed method is superior to the traditional round off method and can reduce the value of the objective function to 41%-74%.

  1. Signal-adapted FIR Filter Banks Without Perfect-reconstruction Property

    Institute of Scientific and Technical Information of China (English)

    SHUIPenglang; ZHANGAihua

    2005-01-01

    A time-domain approach is proposed to design signal-adapted FIR (Finite impulse response) filter banks without the perfect reconstruction property. For a given Wide sense stationary (WSS) input process and a total bit budget, it is a highly nonlinear and large size optimization problem to design the optimal FIR filter bank that minimizes the sum of the quantization distortion and systematic distortion. Thus, the design algorithm is crucial, in particular, selection of the initial filter bank. Here, the FIR approximation of the optimal IIR biorthogonal filter bank is used as the initial filter bank and an ad hoc three-stage algorithm is developed to solve the optimization problem. The numerical results show: the design achieves large subband coding gains (GSBC) that are close to or exceed the GSBC's of the optimal IIR biorthogonal filter banks.

  2. Effects of Bamboo Fargesia murielae on Plant Diversity in Fir Forest on Mountain Shennongjia

    Institute of Scientific and Technical Information of China (English)

    Li Zhaohua; Manfred Denich; Thomas Borsch

    2004-01-01

    Simultaneous flowering caused a gregarious dieback of umbrella bamboo (Fargesia murielae) all over the world in 1993-2000. Mountain Shennongjia in Central China's Hubei Province is the only native home of umbrella bamboo, where it dominates the understorey of the farges fir (Abies fargesii) forest between 2 400 and 3 100 m, covering the ground for more than one century before a periodically flowering death. Data from 20 quadrats along a vegetation sequence revealed that the density, coverage, and height of umbrella bamboo negatively affected the species richness, diversity, and evenness of vascular plants in the forest. Local climax community of fir-bamboo was the poorest in species diversity, while the bamboo-free communities (i.e. shrubs and meadows) were bearing a higher species diversity. The simultaneous dieback of umbrella bamboo is an ecological release, which can periodically promote the plant diversity in the fir forest.

  3. AN ITERATIVE ALGORITHM FOR OPTIMAL DESIGN OF NON-FREQUENCY-SELECTIVE FIR DIGITAL FILTERS

    Institute of Scientific and Technical Information of China (English)

    Duan Miyi; Sun Chunlai; Liu Xin; Tian Xinguang

    2008-01-01

    This paper proposes a novel iterative algorithm for optimal design of non-frequency-se-lective Finite Impulse Response (FIR) digital filters based on the windowing method. Different from the traditional optimization concept of adjusting the window or the filter order in the windowing design of an FIR digital filter,the key idea of the algorithm is minimizing the approximation error by succes-sively modifying the design result through an iterative procedure under the condition of a fixed window length. In the iterative procedure,the known deviation of the designed frequency response in each iteration from the ideal frequency response is used as a reference for the next iteration. Because the approximation error can be specified variably,the algorithm is applicable for the design of FIR digital filters with different technical requirements in the frequency domain. A design example is employed to illustrate the efficiency of the algorithm.

  4. WOOD-WATER RELATIONSHIPS AND BIOLOGICAL DURABILITY OF HEAT-TREATED TAURUS FIR WOOD

    Directory of Open Access Journals (Sweden)

    Bekir Cihad BAL

    2015-09-01

    Full Text Available In this study, Taurus Fir (Abies cilicica wood was treated with hot air at temperatures of 160, 190 and 220°C for 2h durations. After heat treatment, some physical properties and wood-water relationships were evaluated, such as mass loss, density, tangential swelling, radial swelling, volumetric swelling, swelling anisotropy, and fiber saturation point. In addition, the biological durability of Taurus Fir wood was tested in the laboratory with the soil contact test, and determined weight loss. The relationships between mass loss and some of the tested properties were determined using regression analysis. The results showed that heat treatment at 220°C had significant effects on the physical properties and the biological durability of Taurus Fir wood. Further, it was determined that there was a linear-negative correlation between weight loss and mass loss.

  5. Design of Full-Band and Low-Pass FIR Differentiators: A Comparative Study

    Science.gov (United States)

    Mekhnache, C.; Ferdi, Y.; Taleb-Ahmed, A.

    2008-06-01

    Digital differentiators are useful in many fields of sciences and engineering. They can be designed using two approaches, namely, FIR filters design and FIR filters design. This paper is concerned by the first one in which great interest in the design of digital differentiators has encouraged the development of various design methods. The widely used methods for FIR differentiators are those based on criteria L1, L2, L∞ and that based on Taylor series. A comparison between these methods is carried out in terms of approximation accuracy and computational complexity. Numeric examples are presented to illustrate the performance of each method. It was found that the design results obtained by least squares method for fullband and low-pass differentiators are better than the other ones.

  6. Effect of compression on hydroscopicity of extracted Chinese fir heartwood

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In order to clarify the effects of extraction and compression on the hydroscopicity of wood, Chinese fir (Cunninghamia laneeolata Hook.) heartwood samples with or without extraction were radially or tangentially compressed under water-saturated condition at room temperature. Warm water and 1% sodium hydroxide were used as different solutions for extraction. Water absorp-tion capacity and moisture adsorption isotherms of the eornpressed samples were then tested. The fractai dimension of internal wood surfaces (Dfs) was calculated based on adsorption isotherms by FHH equation. Results showed that in both compressed groups, the hydroseopieity of samples extracted by sodium hydroxide solution improved greatly, while that of samples extracted by warm water changed little, compared with that of water-saturated samples. Recovery of set and the change of hydroscopic environment inside wood were main reasons for the difference of water absorption among water-saturated samples and samples extracted with warm water and sodium hydroxide solution. The swelling rate of samples extracted by sodium hydroxide solution significantly increased.Moreover, the swelling rate in the tangential direction of tangentially compressed samples was obviously higher than that in radial direction of radially compressed ones, Des values of woods extracted by warm water and sodium hydroxide solution decreased by 0.002 and 0.007 in a radially compressed group and by 0.013 and 0.013 in a tangentially compressed group, compared to those of water-saturated one. Therefore, the conclusion can be made that the extraction and compression treatments used in this study have no obvious effects on internal wood surface.

  7. Species delimitation, phylogeny and evolutionary demography of co-distributed, montane frogs in the southern Brazilian Atlantic Forest.

    Science.gov (United States)

    Firkowski, Carina R; Bornschein, Marcos R; Ribeiro, Luiz F; Pie, Marcio R

    2016-07-01

    The Brazilian Atlantic Forest (BAF) is recognized as one of the world's biodiversity hotspots, with even more species per unit of area than the Amazon, however the mechanisms that led to such astonishing diversity are yet to be fully understood. In this study, we investigate the diversification of two co-distributed frog genera associated with montane areas of southern BAF: Melanophryniscus (Bufonidae) and Brachycephalus (Brachycephalidae). Species delimitation methods using mitochondrial and nuclear loci supported the existence of a remarkable number of highly endemic species in each genus, most of which occupy only one or a few adjacent mountaintops. Their timing of diversification was highly congruent, supporting recent speciation events within the past 600 thousand years. Extended Bayesian skyline plots indicate that most populations have remained relatively stable in size across the evolutionary past, with recent growth after 0.15My, suggesting that the drastic changes found in previous studies on lowland frog species were not shared by these montane taxa. These results are consistent with the existence of a montane refugium in southern BAF, allowing species persistence through the climatic shifts experienced along the BAF during the Quaternary. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Population Trends of Central European Montane Birds Provide Evidence for Adverse Impacts of Climate Change on High-Altitude Species.

    Directory of Open Access Journals (Sweden)

    Jiří Flousek

    Full Text Available Climate change is among the most important global threats to biodiversity and mountain areas are supposed to be under especially high pressure. Although recent modelling studies suggest considerable future range contractions of montane species accompanied with increased extinction risk, data allowing to test actual population consequences of the observed climate changes and identifying traits associated to their adverse impacts are very scarce. To fill this knowledge gap, we estimated long-term population trends of montane birds from 1984 to 2011 in a central European mountain range, the Giant Mountains (Krkonoše, where significant warming occurred over this period. We then related the population trends to several species' traits related to the climate change effects. We found that the species breeding in various habitats at higher altitudes had more negative trends than species breeding at lower altitudes. We also found that the species moved upwards as a response to warming climate, and these altitudinal range shifts were associated with more positive population trends at lower altitudes than at higher altitudes. Moreover, long-distance migrants declined more than residents or species migrating for shorter distances. Taken together, these results indicate that the climate change, besides other possible environmental changes, already influences populations of montane birds with particularly adverse impacts on high-altitude species such as water pipit (Anthus spinoletta. It is evident that the alpine species, predicted to undergo serious climatically induced range contractions due to warming climate in the future, already started moving along this trajectory.

  9. Population Trends of Central European Montane Birds Provide Evidence for Adverse Impacts of Climate Change on High-Altitude Species.

    Science.gov (United States)

    Flousek, Jiří; Telenský, Tomáš; Hanzelka, Jan; Reif, Jiří

    2015-01-01

    Climate change is among the most important global threats to biodiversity and mountain areas are supposed to be under especially high pressure. Although recent modelling studies suggest considerable future range contractions of montane species accompanied with increased extinction risk, data allowing to test actual population consequences of the observed climate changes and identifying traits associated to their adverse impacts are very scarce. To fill this knowledge gap, we estimated long-term population trends of montane birds from 1984 to 2011 in a central European mountain range, the Giant Mountains (Krkonoše), where significant warming occurred over this period. We then related the population trends to several species' traits related to the climate change effects. We found that the species breeding in various habitats at higher altitudes had more negative trends than species breeding at lower altitudes. We also found that the species moved upwards as a response to warming climate, and these altitudinal range shifts were associated with more positive population trends at lower altitudes than at higher altitudes. Moreover, long-distance migrants declined more than residents or species migrating for shorter distances. Taken together, these results indicate that the climate change, besides other possible environmental changes, already influences populations of montane birds with particularly adverse impacts on high-altitude species such as water pipit (Anthus spinoletta). It is evident that the alpine species, predicted to undergo serious climatically induced range contractions due to warming climate in the future, already started moving along this trajectory.

  10. Recent rates of carbon accumulation in montane fens ofYosemite National Park, California, U.S.A.

    Science.gov (United States)

    Drexler, Judith; Fuller, Christopher C.; Orlando, James; Moore, Peggy E.

    2016-01-01

    Little is known about recent rates of carbon storage in montane peatlands, particularly in the western United States. Here we report on recent rates of carbon accumulation (past 50 to 100 years) in montane groundwater-fed peatlands (fens) of Yosemite National Park in central California, U.S.A. Peat cores were collected at three sites ranging in elevation from 2070 to 2500 m. Core sections were analyzed for bulk density, % organic carbon, and 210Pb activities for dating purposes. Organic carbon densities ranged from 0.026 to 0.065 g C cm-3. Mean vertical accretion rates estimated using210Pb over the 50-year period from ∼1960 to 2011 and the 100-year period from ∼1910 to 2011 were 0.28 (standard deviation = ±0.09) and 0.18 (±-0.04) cm yr-1, respectively. Mean carbon accumulation rates over the 50- and 100-year periods were 95.4 (±25.4) and 74.7 (±17.2) g C m-2 yr-1, respectively. Such rates are similar to recent rates of carbon accumulation in rich fens in western Canada, but more studies are needed to definitively establish both the similarities and differences in peat formation between boreal and temperate montane fens.

  11. Demographic processes in the montane Atlantic rainforest: molecular and cytogenetic evidence from the endemic frog Proceratophrys boiei.

    Science.gov (United States)

    Amaro, Renata Cecília; Rodrigues, Miguel Trefaut; Yonenaga-Yassuda, Yatiyo; Carnaval, Ana Carolina

    2012-03-01

    Historical climatic refugia predict genetic diversity in lowland endemics of the Brazilian Atlantic rainforest. Yet, available data reveal distinct biological responses to the Last Glacial Maximum (LGM) conditions across species of different altitudinal ranges. We show that species occupying Brazil's montane forests were significantly less affected by LGM conditions relative to lowland specialists, but that pre-Pleistocene tectonics greatly influenced their geographic variation. Our conclusions are based on palaeoclimatic distribution models, molecular sequences of the cytochrome b, 16S, and RAG-1 genes, and karyotype data for the endemic frog Proceratophrys boiei. DNA and chromosomal data identify in P. boiei at least two broadly divergent phylogroups, which have not been distinguished morphologically. Cytogenetic results also indicate an area of hybridization in southern São Paulo. The location of the phylogeographic break broadly matches the location of a NW-SE fault, which underwent reactivation in the Neogene and led to remarkable landscape changes in southeastern Brazil. Our results point to different mechanisms underpinning diversity patterns in lowland versus montane tropical taxa, and help us to understand the processes responsible for the large number of narrow endemics currently observed in montane areas of the southern Atlantic forest hotspot.

  12. Comparison of wood-inhabiting myxomycetes in subalpine and montane coniferous forests in the Yatsugatake Mountains of Central Japan.

    Science.gov (United States)

    Takahashi, Kazunari; Harakon, Yuichi

    2012-05-01

    To demonstrate altitudinal gradients (and resulting temperatures) that affect myxomycete biodiversity and species composition, we statistically compared myxomycete assemblages between a subalpine coniferous forest and a montane pine forest within the region of the Yatsugatake Mountains, Nagano Prefecture, Central Japan. In summer and autumn field surveys during 2003-2010, 53 myxomycete taxa (with varieties treated as species) were observed from 639 records of fruiting bodies in the subalpine forest and 32 taxa were detected from 613 records in the montane forest. There were 20 species in common between the assemblages and the percentage similarity index was 0.400. Myxomycete biodiversity was higher in the subalpine than in the montane forest. Nine myxomycete species were statistically frequent occurrences in the subalpine forest and appeared in autumn: Lamproderma columbinum, Cribraria macrocarpa, Trichia botrytis, Physarum newtonii, Diderma ochraceum, Enteridium splendens, Elaeomyxa cerifera, Trichia verrucosa, and Colloderma oculatum. Five species were restricted to appear in the subalpine forest: Cribraria purpurea, Cribraria rufa, Cribraria ferruginea, Cribraria piriformis, and Lepidoderma tigrinum. Dead wood in the subalpine forest provided a breeding habitat for specific myxomycetes that inhabit cold areas; that is those areas having geographical features of decreasing temperature and increasing elevation, such as the temperate area of Central Japan.

  13. Effect of stand edge on the natural regeneration of spruce, beech and Douglas-fir

    Directory of Open Access Journals (Sweden)

    Lumír Dobrovolný

    2012-01-01

    Full Text Available Our work aimed at studying the strategy of woody plants regeneration during the regeneration of a spruce stand with the admixture of beech and Douglas-fir by border cutting (NW-SE aspect on acidic sites of higher elevations in the Bohemian-Moravian Upland. Spruce is better adapted to bear shade than Douglas-fir. Nevertheless, in optimal light conditions up to a distance of ca. 35 m (about 16% DIFFSF from the stand edge, the Douglas-fir can put the spruce into danger as to height growth. By contrast to beech, the density of spruce is significantly higher within the distance of 45 m (about 15% DIFFSF from the stand edge but further on the situation would change to the benefit of beech. The density of Douglas-fir significantly dominates over beech within a distance of 35 m from the stand edge; from 55 m (less than 15% DIFFSF, the situation changes in favour of beech. Beech can survive in full shade deep in the stand core waiting for its opportunity to come. As compared to spruce and Douglas-fir, the height growth of beech was at all times significantly greater at a distance of 25 m from the stand edge. Converted to practical conditions, spruce and Douglas-fir with individually admixed beech seedlings showed good prosperity approximately up to a distance of one stand height from the edge. A mixture of spruce and beech did well at a greater distance but good prosperity at a distance of 2–3 stand heights was shown only by beech. Thus, border regeneration eliminates disadvantages of the climatic extremes of clear-cutting and specifics of shelterwood felling during which one – usually shade-tolerant tree species dominates in the natural regeneration (e.g. beech.

  14. Climate Change, Wildfires and Fir Forests in Greece: Perceptions of Forest Managers

    Directory of Open Access Journals (Sweden)

    Ioannis Mitsopoulos

    2015-05-01

    Full Text Available Background and Purpose: The potential impact that climate change may have on fire regime in ecosystems that are not fire-dependent emerges from fires that are nowadays spreading over higher altitudes and northern latitudes. The effects of fire occurrence in high elevation forests of Greece became apparent during the last few years when a number of large forest fires burned a significant number of high altitude fir ecosystems. This paper describes a study that investigated perceptions of wildfire risk to fir ecosystems of Greece in the context of climate change among a sample of Greek forestry experts by conducting personal interviews. Materials and Methods: A total of 63 forest experts answered the developed survey from 43 different forest management units covering all forestry agencies which manage fir forests in the country. The perceived fire risk and management to fir forest ecosystems was assessed by means of a subset of scales previously identified as relevant to climate change and to all fire management aspects, such as fire prevention, fire suppression and post fire treatments. Results: Increased fire risk was rated as a quite important issue in fir forests during the last few years, while the adapting options to climate change are not implemented mainly due to budget and personnel constrains. According to forest experts, fire prevention in fir forests under climate change should be focused on public awareness and fuel management. Nevertheless, the survey results indicate that there is also a need for specific fire prevention measures such as the type of logging activities and other technical measures. The result of this survey highlighted the need for the establishment of a new firefighting organization and for the better coordination of all involved parties during fire suppression. Conclusions: The findings of the current study can be critically important in determining how forest fire management considerations are incorporated into

  15. Two-band hybrid FIR-IIR filters for image compression.

    Science.gov (United States)

    Lin, Jianyu; Smith, Mark J T

    2011-11-01

    Two-band analysis-synthesis filters or wavelet filters are used pervasively for compressing natural images. Both FIR and IIR filters have been studied in this context, the former being the most popular. In this paper, we examine the compression performance of these two-band filters in a dyadic wavelet decomposition and attempt to isolate features that contribute most directly to the performance gain. Then, employing the general exact reconstruction condition, hybrid FIR-IIR analysis-synthesis filters are designed to maximize compression performance for natural images. Experimental results are presented that compare performance with the popular biorthogonal filters in terms of peak SNR, subjective quality, and computational complexity.

  16. Boundary implications for frequency response of interval FIR and IIR filters

    Science.gov (United States)

    Bose, N. K.; Kim, K. D.

    1991-01-01

    It is shown that vertex implication results in parameter space apply to interval trigonometric polynomials. Subsequently, it is shown that the frequency responses of both interval FIR and IIR filters are bounded by the frequency responses of certain extreme filters. The results apply directly in the evaluation of properties of designed filters, especially because it is more realistic to bound the filter coefficients from above and below instead of determining those with infinite precision because of finite arithmetic effects. Illustrative examples are provided to show how the extreme filters might be easily derived in any specific interval FIR or IIR filter design problem.

  17. MCH pheromone for preventing Douglas-fir beetle infestation in windthrown trees

    OpenAIRE

    McGregor, M. D.; Furniss, M. M.; Oaks, R. D.; Gibson, K.E.; Meyer, H E

    1984-01-01

    A granular controlled-release formulation (98 percent inert, 2 percent 3-methyl-2-cyclohexen-1-one) was applied May 11-13, 1982, at 4.48 kg/ha to 76.9 ha of uninfested windthrown Douglas-fir by helicopter with a modified aerial spreader of 1.13 m³ capacity. Granules measured on treated plots averaged 2.04-2.69 kg/ha, sufficient to reduce Douglas-fir beetle (Dendroctonus pseudotsugae) infestation 96.4 percent by late June. The same MCH treatment reduced spruce beetle (Dendroctonus rufipennis) ...

  18. Modification of Chinese fir with alkyl ketene dimer (AKD: Processing and characterization

    Directory of Open Access Journals (Sweden)

    Zengqian Shi

    2013-02-01

    Full Text Available A process for the chemical modification of Chinese fir with alkyl ketene dimer (AKD was studied. The hydrophobicity of the resulting products was evaluated by characterization of the equilibrium moisture content, water-surface contact angle, water absorption coefficient, and anti-swelling efficiency. The results indicated that when 5% AKD solution was used, the modified wood generally showed good hydrophobicity and improved dimensional stability. The result of boiling water and hexane extraction tests showed that the modified fir possessed very stable hydrophobicity.

  19. Study on Drying Characteristic of Chinese Fir and Poplar Plantation Wood

    Institute of Scientific and Technical Information of China (English)

    ZHOUYongdong; LIXiaoling

    2004-01-01

    The drying characteristic was studied for plantation wood of Chinese fir and poplar, which are typical plantation wood of southern and northern part of China, respectively. Through lO0-degree-method the drying characteristic and basic drying condition were gotten, then drying schedule was developed for practical drying, the results showed that the drying schedule is suitable for Chinese fir and poplar plantation lumber, but shrinkage is large. The recommendation was made that enough dead weight is needed to decrease shrinkage in drying process. The drying quality of the two species of lumber is good in conventional drying method.

  20. An audio FIR-DAC in a BCD process for high power Class-D amplifiers

    OpenAIRE

    Doorn, T.S.; Tuijl, van, B.A.J.; Schinkel, D.; Annema, A.J.; Berkhout, M.; Nauta, B.

    2005-01-01

    A 322 coefficient semi-digital FIR-DAC using a 1-bit PWM input signal was designed and implemented in a high voltage, audio power bipolar CMOS DMOS (BCD) process. This facilitates digital input signals for an analog class-D amplifier in BCD. The FIR-DAC performance depends on the ISI-resistant nature of this PWM-signal. An impulse response with only positive coefficients was chosen, because of its resistance to deadzone and mismatch. With a DAC current of 0.5 mA, the dynamic range is 111 dB (...

  1. Ecology of Mabuya agilis (Squamata: Scincidae from a montane atlantic rainforest area in Southeastern Brazil

    Directory of Open Access Journals (Sweden)

    Teixeira, Rogério L.

    2003-05-01

    Full Text Available Alguns aspectos da ecologia (principalmente reprodução e dieta do lagarto scincídeo Mabuya agilis foram estudados com base em amostras mensais realizadas de dezembro de 1997 a abril de 1999 em uma área de floresta tropical serrana no estado do Espírito Santo, sudeste do Brasil. Dos 197 espécimes coletados, 82 eram machos, 110 eram fêmeas, e o resto não pôde ser corretamente sexado. Lagartos variaram em comprimento rostro-coacal de 30 a 96 mm e foram sexualmente dimórficos em tamanho, com fêmeas atingindo maiores tamanhos que machos. A menor fêmea grávida mediu 54.0 mm. O tamanho da ninhada para 49 fêmeas grávidas variou de 2 a 9 (média = 5.7 e esteve positiva e significativamente relacionado ao tamanho dos lagartos. As presas dominantes na dieta de M. agilis foram baratas, ortópteros e aranhas. A população de M. agilis aqui estudada diferiu de outras populações conspecíficas previamente estudadas em hábitats de «restinga» nos estados do Rio de Janeiro e Espírito Santo, sendo que os indivíduos crescem a tamanhos maiores e a fecundidade é mais alta, possivelmente devido a uma maior disponibilidade de alimento no hábitat de floresta tropical serrana Some aspects of the ecology (mainly reproduction and diet of the skink Mabuya agilis were studied based on monthly samples taken from December 1997 to April 1999 at a montane rainforest area in Espírito Santo state, southeastern Brazil. Of 197 collected specimens, 82 were males, 110 were females, and the rest could not be properly sexed. Lizards varied in snout-vent length (SVL from 30 to 96 mm and were sexually dimorphic in size, with females growing larger than males. The smallest gravid female measured 54.0 mm in SVL. Litter size of 49 gravid females varied from 2 to 9 (mean= 5.7 and was positively and significantly related to lizard SVL. The dominant prey items in the diet of M. agilis were cockroaches, orthopterans and spiders. The population of M. agilis here studied

  2. Dinitrogen emissions as an overlooked key component of the N balance of montane grasslands

    Science.gov (United States)

    Zistl-Schlingmann, Marcus; Feng, Jinchao; Kiese, Ralf; Stephan, Ruth; Dannenmann, Michael

    2017-04-01

    Numerous studies have been conducted on the emission dynamics and annual budget of the atmospheric pollutants and primary or secondary greenhouse gases NOx, NH3 and N2O, i.e. gaseous N losses which can play an important role in the N budget of ecosystems. Due to still existing methodical problems in their quantification, considerably less is known on soil dinitrogen (N2) emissions, an inert gas with no hazardous effects on the environment. Understanding of soil N2 emissions however may be important to better understand and manage the N balance of ecosystems and also to mitigate the emissions of the precursor and potent greenhouse gas N2O. Here we quantified soil N2 emissions from montane grasslands used for dairy farming as affected by climate change simulation (reduced annual precipitation, increased temperature). For this purpose, plant-soil-mesocosms were brought from field sites of different elevation to the laboratory for direct simultaneous quantification of soil N2 and N2O emissions by use of the Helium soil core method. Immediately after the measurements, the plant-soil mesocosms were reburied at the sites. Using this approach we found that under current climate conditions, soil N2 emissions exceeded soil N2O emissions by several orders of magnitude and increased from 25 kg N ha-1 year-1 (present climate) to 50 kg N ha-1 year-1 (climate change treatment). Because this approach based on monthly sampling cannot accurately consider N gas emission peaks after manure fertilization, measurements were supplemented by a laboratory incubation approach. In this experiment, the response of all N gas emissions (NH3, NO, N2O, N2) to manure fertilization (50 kg N ha-1) was monitored with subdaily temporal resolution until emissions had diminished. Total N gas losses amounted to roughly half of the supplied N by manure application. Surprisingly, we found that N2 but not NH3 dominated fertilizer-derived gaseous N losses, accounting for 78 to 85 % of total gaseous N losses

  3. Montane meadows and hydrologic connections between forests and streams in the Sierra Nevada, California

    Science.gov (United States)

    Lucas, R. G.; Conklin, M. H.

    2013-12-01

    Montane meadows of the Sierra Nevada often serve as the interface between up-gradient forested area and down-gradient streamflow. We investigated the roles that meadow groundwater and evapotranspiration play in the greater catchment water cycle using a water-column data from monitoring wells and piezometers in two meadows for water years 2008-2012. Analyses include mass balance and modeling using 1-D HYDRUS. Though spatially heterogeneous, groundwater fluxes contribute to evapotranspiration (ETg) across the meadows, and are constrained by surface-water discharge. Near the meadow center groundwater discharges occur for the duration of the snow-free season, ET¬g is relatively low. At the meadow edge the groundwater flux changes from discharge to recharge when the growing season begins; also ETg increases, and major-ion concentrations in groundwater are more dilute than those near the meadow center. When groundwater is discharged throughout the meadow during snowmelt, the stream-water ion content more closely resembles water sampled from wells at the meadow edge. These trends change as the summer season progresses--groundwater is no longer discharged at the meadow edge and the stream water ion concentration matches the groundwater sampled from the center of the meadow. Slug tests performed in the monitoring wells indicate a saturated hydraulic conductivity (Kh) of meadow substrates between 10-5 and 10-6 m s-1. The upper end of this range reflects substrate with large sand fractions, while lower values reflect finer-grained or higher-organic-content substrate. Applying the higher Kh values to groundwater gradients during snowmelt results in groundwater discharge rates greater than streamflow measured at the meadow outlet. This suggests that the peat layer at the meadow surface, with significantly lower Kh values, retards groundwater discharge from the meadow during snowmelt. ETg signals in wells at the meadow edge and in wells installed just outside of the meadow

  4. Energy Balance Alterations Due to Cropland Conversion in a Tropical Montane Environment: Shaded Coffee to Sugarcane

    Science.gov (United States)

    Alvarado-Barrientos, M. S.; Holwerda, F.; Salazar-Martinez, D.

    2014-12-01

    Although land use change (LUC) is an important driver of changes in climate, very limited field observations of atmosphere-landscape interactions exist in tropical montane zones to examine the extent to which LUCs affect climate locally and regionally. The lack of ground observations hampers the evaluation of satellite-derived datasets of land surface parameters as well as the validation of regional climate models. The first results of an ongoing study of the climate effects of a LUC trajectory in the lower montane region (1200 m a.s.l.) of central Veracruz, Mexico, are presented. The radiation balance, turbulent fluxes and soil heat flux were measured in order to obtain field-derived land surface parameters (albedo and Bowen ratio) of two contrasting land uses: shaded coffee (CO) and sugarcane (SU) plantations. Measurements were conducted on days representing different seasons and crop stages during 2014: cold-dry (January), warm-dry (March) and warm-wet (July). Average noon-time albedo was higher for SU than for CO (0.14 vs. 0.11). Soil heat flux was on average 13% and 12% of net radiation for SU and CO, respectively. Preliminary turbulent flux calculations indicate that noon-time Bowen ratio was higher for sugar cane (range: 1.0-1.5) compared to shaded coffee (range: 0.5-1.0). Seasonal (and crop-stage) changes affected the surface parameters of SU mostly. For example, the SU Bowen ratio increased with decreasing soil moisture, indicating soil moisture limitation for transpiration reducing latent heat flux. In contrast, the shaded coffee Bowen ratio remained relatively constant across measuring periods. The energy balance closure was 80% (pending complete eddy covariance data corrections). These results indicate that the conversion of shaded coffee to sugarcane result in a drier and hotter lower atmosphere. Next steps include examining the implications of these local changes for regional climate, with special attention to cloud formation, using a regional model

  5. Demonstrating A New Census of INfrared Galaxies with ALMA (DANCING-ALMA). I. FIR Size and Luminosity Relation at z = 0-6

    OpenAIRE

    Fujimoto, Seiji; Ouchi, Masami; Shibuya, Takatoshi; Nagai, Hiroshi

    2017-01-01

    We present the large statistics of the galaxy effective radius in the rest-frame far-infrared (FIR) wavelength Re(FIR) obtained from 1258 deep Atacama Large Millimeter/submillimeter Array (ALMA) 1-mm band maps that are open for public by 2016 December. Our ALMA sample consists of 736 sources at z=0-6 that typically have the star-formation rate of ~50-1000 M$_{\\odot}$/yr and the stellar mass of ~10$^{10}$-10$^{11.5}$ M$_{\\odot}$. We homogeneously derive Re(FIR) and FIR luminosity L_FIR of our ...

  6. Temporal germ cell development strategy during continuous spermatogenesis within the montane lizard, Sceloporus bicanthalis (Squamata; Phrynosomatidae).

    Science.gov (United States)

    Gribbins, Kevin; Anzalone, Marla; Collier, Matthew; Granados-González, Gisela; Villagrán-Santa Cruz, Maricela; Hernández-Gallegos, Oswaldo

    2011-10-01

    Sceloporus bicanthalis is a viviparous lizard that lives at higher elevations in Mexico. Adult male S. bicanthalis were collected (n = 36) from the Nevado de Toluca, Mexico (elevation is 4200 m) during August to December, 2007 and January to July, 2008. Testes were extracted, fixed in Trumps, and dehydrated in a graded series of ethanol. Tissues were embedded, sectioned (2 μm), stained, and examined via a light microscope to determine the spermatogenic developmental strategy of S. bicanthalis. In all months examined, the testes were spermiogenically active; based on this, plus the presence of sperm in the lumina of seminiferous tubules, we inferred that S. bicanthalis had year-round or continuous spermatogenesis, unlike most reptiles that occupy a temperate or montane habitat. It was recently reported that seasonally breeding reptiles had a temporal germ cell development strategy similar to amphibians, where germ cells progress through spermatogenesis as a single population, which leads to a single spermiation event. This was much different than spatial development within the testis of other derived amniotes. We hypothesized that germ cell development was temporal in S. bicanthalis. Therefore, we wanted to determine whether reptiles that practice continuous spermatogenesis have a mammalian-like spatial germ cell development, which is different than the typical temperate reptile exhibiting a temporal development. In the present study, S. bicanthalis had a temporal development strategy, despite its continuous spermatogenic cycle, making them similar to tropical anoles. Copyright © 2011 Elsevier Inc. All rights reserved.

  7. Species association in tropical montane rain forest at two successional stages in Diaoluo Mountain, Hainan

    Institute of Scientific and Technical Information of China (English)

    Fude LIU; Wenjin WANG; Ming ZHANG; Jianwei ZHENG; Zhongsheng WANG; Shiting ZHANG; Wenjie YANG; Shuqing AN

    2008-01-01

    Species association is one of the basic concepts in community succession. There are different viewpoints on how species interaction changes with the progress of succession. In order to assess these relationships, we examined species associations in the tropical montane rain forest at early and late successional stages in Diaoluo Mountain, Hainan Island. Based on data from a 2 × 2 contingency table of species presence or absence, statist-ical methods including analysis of species association and χ2 tests were applied. The results show that: 1) an overall positive association was present among tree species in the communities during the two successional stages and were statistically significant at the late stage. The number of species pairs with positive and negative associations decreased throughout the process of succession, while the number with null associations was greatly increased. The same trend existed among the dominant and compan-ion species. The results indicate that the communities are developing towards a stable stage where the woody species coexist in harmony. 2) In the early-established and later invading species, all positive associations were not signifi-cant. Compared with positive and null associations, fewer negative associations were found. This implies that these species are inclined to coexist independently through por-tioning of resources. 3) Among the later invading species, positive associations were significant and no negative associations were found which suggest that these species have similar adaptive ability in the habitat and occupied overlapping niches in the community.

  8. Pervasive Effects of Wildfire on Foliar Endophyte Communities in Montane Forest Trees.

    Science.gov (United States)

    Huang, Yu-Ling; Devan, M M Nandi; U'Ren, Jana M; Furr, Susan H; Arnold, A Elizabeth

    2016-02-01

    Plants in all terrestrial ecosystems form symbioses with endophytic fungi that inhabit their healthy tissues. How these foliar endophytes respond to wildfires has not been studied previously, but is important given the increasing frequency and intensity of severe wildfires in many ecosystems, and because endophytes can influence plant growth and responses to stress. The goal of this study was to examine effects of severe wildfires on endophyte communities in forest trees, with a focus on traditionally fire-dominated, montane ecosystems in the southwestern USA. We evaluated the abundance, diversity, and composition of endophytes in foliage of Juniperus deppeana (Cupressaceae) and Quercus spp. (Fagaceae) collected contemporaneously from areas affected by recent wildfire and paired areas not affected by recent fire. Study sites spanned four mountain ranges in central and southern Arizona. Our results revealed significant effects of fires on endophyte communities, including decreases in isolation frequency, increases in diversity, and shifts in community structure and taxonomic composition among endophytes of trees affected by recent fires. Responses to fire were similar in endophytes of each host in these fire-dominated ecosystems and reflect regional fire-return intervals, with endophytes after fire representing subsets of the regional mycoflora. Together, these findings contribute to an emerging perspective on the responses of diverse communities to severe fire, and highlight the importance of considering fire history when estimating endophyte diversity and community structure for focal biomes.

  9. Diversification of tanagers, a species rich bird group, from lowlands to montane regions of South America

    DEFF Research Database (Denmark)

    Fjeldså, Jon; Rahbek, Carsten

    2006-01-01

    The process of diversification since the late Tertiary was studied by linking together well-resolved phylogenies and species distributions for tanagers (Aves, Thraupini). Species richness patterns reveal very high densities of range-restricted species in the Andes, and to a lesser extent in the A......The process of diversification since the late Tertiary was studied by linking together well-resolved phylogenies and species distributions for tanagers (Aves, Thraupini). Species richness patterns reveal very high densities of range-restricted species in the Andes, and to a lesser extent...... be explained well from topography and landscape complexity. Phylogenetically old species are mainly found along the Andes and along the Rio coast of Brazil. Most other areas outside the Andes probably had very moderate rates of later diversification. In contrast, the humid tropical Andes region was a centre...... of intensive speciation throughout the evolutionary history of the group, and species richness patterns here seem largely to be driven by the rate of speciation, with further diversification from the highlands into adjacent lowlands. The diversification process in montane areas may be related to high...

  10. A new species of Noblella (Amphibia, Anura, Craugastoridae from the humid montane forests of Cusco, Peru

    Directory of Open Access Journals (Sweden)

    Alessandro Catenazzi

    2015-08-01

    Full Text Available A new species of Noblella is described from the humid montane forest of the Región Cusco in Peru. Specimens were collected at 2330–2370 m elevation in Madre Selva, near Santa Ana, in the province of La Convención. The new species is readily distinguished from all other species of Noblella by having a broad, irregularly shaped, white mark on black background on chest and belly. The new species further differs from known Peruvian species of Noblella by the combination of the following characters: tympanic membrane absent, small tubercles on the upper eyelid and on dorsum, tarsal tubercles or folds absent, tips of digits not expanded, no circumferential grooves on digits, dark brown facial mask and lateral band extending from the tip of the snout to the inguinal region. The new species has a snout-to-vent length of 15.6 mm in one adult male and 17.6 mm in one adult female. Like other recently described species in the genus, this new Noblella inhabits high-elevation forests in the Andes and likely has a restricted geographic distribution.

  11. Structure of the epiphyte community in a tropical montane forest in SW China.

    Directory of Open Access Journals (Sweden)

    Mingxu Zhao

    Full Text Available Vascular epiphytes are an understudied and particularly important component of tropical forest ecosystems. However, owing to the difficulties of access, little is known about the properties of epiphyte-host tree communities and the factors structuring them, especially in Asia. We investigated factors structuring the vascular epiphyte-host community and its network properties in a tropical montane forest in Xishuangbanna, SW China. Vascular epiphytes were surveyed in six plots located in mature forests. Six host and four micro-site environmental factors were investigated. Epiphyte diversity was strongly correlated with host size (DBH, diameter at breast height, while within hosts the highest epiphyte diversity was in the middle canopy and epiphyte diversity was significantly higher in sites with canopy soil or a moss mat than on bare bark. DBH, elevation and stem height explained 22% of the total variation in the epiphyte species assemblage among hosts, and DBH was the most important factor which alone explained 6% of the variation. Within hosts, 51% of the variation in epiphyte assemblage composition was explained by canopy position and substrate, and the most important single factor was substrate which accounted for 16% of the variation. Analysis of network properties indicated that the epiphyte host community was highly nested, with a low level of epiphyte specialization, and an almost even interaction strength between epiphytes and host trees. Together, these results indicate that large trees harbor a substantial proportion of the epiphyte community in this forest.

  12. Analysis of the temporal variation of the structure of a montane forest with historical of fire

    Directory of Open Access Journals (Sweden)

    Fernando Bonillo Fernandes

    2012-06-01

    Full Text Available The aim of this study was to evaluate the structural dynamic rates of an shrubs-tree component of a seasonal semideciduous upper montane forest, in Mantiqueira Mountain between 2002 and 2008. We calculated the rates of dynamic according to the number of surviving, dead individuals and recruits, as well as the rates of dynamic for gain and loss of basal area. We verified the spatial differences among the rates along the vegetation gradient parallel to ground elevation. We also studied the correlations between the rates and biotic (initial numbers of trees and initial basal area and abiotic parameters (altimetric quota. We verified that recruitment was higher than mortality, and the gain of basal area was higher than the loses. This result suggests that the forest is expanding, with gain in number of individuals and in basal area. Normally, this result characterizes forests in recuperation after some disturbance. The community sectors (basis, middle and top of hillside didn’t show any differences in terms of dynamic rates. In general, there were few significant correlations between biotic and abiotic parameters and the dynamic rates. The increase of density and basal area, the similarity of dynamic rates among the sectors and the low correlation between parameters and the dynamic of forest’s structure point out that the forest burning occurred in 90’s could be, nowadays, interfering directly in dynamic rates of forest.

  13. Topoclimate effects on growing season length and montane conifer growth in complex terrain

    Science.gov (United States)

    Barnard, D. M.; Barnard, H. R.; Molotch, N. P.

    2017-05-01

    Spatial variability in the topoclimate-driven linkage between forest phenology and tree growth in complex terrain is poorly understood, limiting our understanding of how ecosystems function as a whole. To characterize the influence of topoclimate on phenology and growth, we determined the start, end, and length of the growing season (GSstart, GSend, and GSL, respectively) using the correlation between transpiration and evaporative demand, measured with sapflow. We then compared these metrics with stem relative basal area increment (relative BAI) at seven sites among elevation and aspects in a Colorado montane forest. As elevation increased, we found shorter GSL (-50 d km-1) due to later GSstart (40 d km-1) and earlier GSend (-10 d km-1). North-facing sites had a 21 d shorter GSL than south-facing sites at similar elevations (i.e. equal to 200 m elevation difference on a given aspect). Growing season length was positively correlated with relative BAI, explaining 83% of the variance. This study shows that topography exerts strong environmental controls on GSL and thus forest growth. Given the climate-related dependencies of these controls, the results presented here have important implications for ecosystem responses to changes in climate and highlight the need for improved phenology representation in complex terrain.

  14. Epiphytic and terrestrial mycorrhizas in a lower montane Costa Rican cloud forest.

    Science.gov (United States)

    Rains, Kai Coshow; Nadkarni, Nalini M; Bledsoe, Caroline S

    2003-10-01

    The epiphyte community is the most diverse plant community in neotropical cloud forests and its collective biomass can exceed that of the terrestrial shrubs and herbs. However, little is known about the role of mycorrhizas in this community. We assessed the mycorrhizal status of epiphytic (Araceae, Clusiaceae, Ericaceae, and Piperaceae) and terrestrial (Clusiaceae, Ericaceae) plants in a lower montane cloud forest in Costa Rica. Arbuscular mycorrhizas were observed in taxa from Araceae and Clusiaceae; ericoid mycorrhizas were observed in ericaceous plants. This is the first report of intracellular hyphal coils characteristic of ericoid mycorrhizas in roots of Cavendishia melastomoides, Disterigma humboldtii, and Gaultheria erecta. Ericaceous roots were also covered by an intermittent hyphal mantle that penetrated between epidermal cells. Mantles, observed uniquely on ericaceous roots, were more abundant on terrestrial than on epiphytic roots. Mantle abundance was negatively correlated with gravimetric soil water content for epiphytic samples. Dark septate endophytic (DSE) fungi colonized roots of all four families. For the common epiphyte D. humboldtii, DSE structures were most abundant on samples collected from exposed microsites in the canopy. The presence of mycorrhizas in all epiphytes except Peperomia sp. suggests that inoculum levels and environmental conditions in the canopy of tropical cloud forests are generally conducive to the formation of mycorrhizas. These may impact nutrient and water dynamics in arboreal ecosystems.

  15. A new species of Noblella (Amphibia, Anura, Craugastoridae) from the humid montane forests of Cusco, Peru.

    Science.gov (United States)

    Catenazzi, Alessandro; Uscapi, Vanessa; von May, Rudolf

    2015-01-01

    A new species of Noblella is described from the humid montane forest of the Región Cusco in Peru. Specimens were collected at 2330-2370 m elevation in Madre Selva, near Santa Ana, in the province of La Convención. The new species is readily distinguished from all other species of Noblella by having a broad, irregularly shaped, white mark on black background on chest and belly. The new species further differs from known Peruvian species of Noblella by the combination of the following characters: tympanic membrane absent, small tubercles on the upper eyelid and on dorsum, tarsal tubercles or folds absent, tips of digits not expanded, no circumferential grooves on digits, dark brown facial mask and lateral band extending from the tip of the snout to the inguinal region. The new species has a snout-to-vent length of 15.6 mm in one adult male and 17.6 mm in one adult female. Like other recently described species in the genus, this new Noblella inhabits high-elevation forests in the Andes and likely has a restricted geographic distribution.

  16. Life in the clouds: are tropical montane cloud forests responding to changes in climate?

    Science.gov (United States)

    Hu, Jia; Riveros-Iregui, Diego A

    2016-04-01

    The humid tropics represent only one example of the many places worldwide where anthropogenic disturbance and climate change are quickly affecting the feedbacks between water and trees. In this article, we address the need for a more long-term perspective on the effects of climate change on tropical montane cloud forests (TMCF) in order to fully assess the combined vulnerability and long-term response of tropical trees to changes in precipitation regimes, including cloud immersion. We first review the ecophysiological benefits that cloud water interception offers to trees in TMCF and then examine current climatological evidence that suggests changes in cloud base height and impending changes in cloud immersion for TMCF. Finally, we propose an experimental approach to examine the long-term dynamics of tropical trees in TMCF in response to environmental conditions on decade-to-century time scales. This information is important to assess the vulnerability and long-term response of TMCF to changes in cloud cover and fog frequency and duration.

  17. A montane Mediterranean climate supports year-round photosynthesis and high forest biomass.

    Science.gov (United States)

    Kelly, Anne E; Goulden, Michael L

    2016-04-01

    The mid-elevation forest of California's Sierra Nevada poses a bioclimatic paradox. Mid-elevation trees experience a montane Mediterranean climate, with near-freezing winter days and rain-free summers. The asynchrony between warmth and water input suggests low primary production, limited by photosynthetic dormancy in winter cold, and again in summer and early autumn with drought, yet this forest is characterized by tall trees and high biomass. We used eddy covariance in a mid-elevation Sierra stand to understand how winter cold and summer drought limit canopy photosynthesis and production. The trees exhibited canopy photosynthesis year-round. Trees avoided winter dormancy, and daytime CO2uptake continued despite a deep snowpack and near-freezing temperatures. Photosynthesis on sunny days continued at half of maximum rates when air temperature was 0 °C. Likewise, the vegetation avoided summer drought dormancy, and high rates of daytime CO2uptake and transpiration continued despite a 5-month period with only negligible water input. We attribute this drought avoidance to deep rooting and availability of deep soil water. Year-round photosynthesis helps explain the large biomass observed in the Sierra Nevada, and implies adaptive strategies that may contribute to the resiliency or vulnerability of Sierran vegetation to climate change.

  18. Elevational ranges of birds on a tropical montane gradient lag behind warming temperatures.

    Directory of Open Access Journals (Sweden)

    German Forero-Medina

    Full Text Available BACKGROUND: Species may respond to a warming climate by moving to higher latitudes or elevations. Shifts in geographic ranges are common responses in temperate regions. For the tropics, latitudinal temperature gradients are shallow; the only escape for species may be to move to higher elevations. There are few data to suggest that they do. Yet, the greatest loss of species from climate disruption may be for tropical montane species. METHODOLOGY/PRINCIPAL FINDINGS: We repeat a historical transect in Peru and find an average upward shift of 49 m for 55 bird species over a 41 year interval. This shift is significantly upward, but also significantly smaller than the 152 m one expects from warming in the region. To estimate the expected shift in elevation we first determined the magnitude of warming in the locality from historical data. Then we used the temperature lapse rate to infer the required shift in altitude to compensate for warming. The range shifts in elevation were similar across different trophic guilds. CONCLUSIONS: Endothermy may provide birds with some flexibility to temperature changes and allow them to move less than expected. Instead of being directly dependent on temperature, birds may be responding to gradual changes in the nature of the habitat or availability of food resources, and presence of competitors. If so, this has important implications for estimates of mountaintop extinctions from climate change.

  19. Commonness and Rarity: Theory and Application of a New Model to Mediterranean Montane Grasslands

    Directory of Open Access Journals (Sweden)

    José M. Rey Benayas

    1999-06-01

    Full Text Available We examined patterns of commonness and rarity among plant species in montane wet grasslands of Iberia. This examination is set within two contexts. First, we expanded on an earlier scheme for classifying species as common or rare by adding a fourth criterion, the ability of that species to occupy a larger or smaller fraction of its potential suitable habitats, i.e., habitat occupancy. Second, we explicated two theories, the superior organism theory and the generalist/specialist trade-off theory. The data consisted of 232 species distributed among 92 plots. The species were measured for mean local abundance, size of environmental volume occupied, percentage of volume occupied, range within Iberia, and range in Europe and the Mediterranean basin. In general, all measures were positively correlated, in agreement with the superior organism theory. However, specialist species were also found. Thus, patterns of commonness and rarity may be due to a combination of mechanisms. Analyses such as ours can also be used as a first step in identifying habitats and species that may be endangered.

  20. A new species of Cladophialophora (hyphomycetes) from boreal and montane bryophytes.

    Science.gov (United States)

    Davey, Marie L; Currah, Randolph S

    2007-01-01

    During a survey of bryophilous fungi from boreal and montane habitats in central Alberta, a hitherto undescribed species of Cladophialophora was recovered from Polytrichum juniperinum, Aulacomnium palustre, and Sphagnum fuscum. On potato dextrose agar (PDA) colonies grew slowly, attaining a diameter of 25 mm after 30 d, were dark grey, velvety, radially sulcate, and convolute and cracked at the centre. Micronematous conidiophores gave rise to branched chains of small (1-2 x 8-22 microm), cylindrical to fusiform conidia with truncate, swollen scars at each end. Phylogenies built on the ITS and ribosomal SSU regions indicate the isolates form a monophyletic clade within the family Herpotrichiellaceae (Chaetothyriales) that is composed of two geographically based groups, each with 99% within-group sequence similarity and 97-98% between-group sequence similarity. A teleomorph has not been found but would likely be similar to species of Capronia. In vitro inoculation of the isolates onto axenically grown P. juniperinum produced no discernible host symptoms, and host penetration could not be detected using light microscopy. The production of polyphenol oxidases by the fungus and the role of other Cladophialophora species as latent endophytes and saprobes suggest that a potential role for the fungus is the degradation of the polyphenol-rich cell walls of mosses. A dichotomous key to species of the genus Cladophialophora is provided.

  1. Structure of the epiphyte community in a tropical montane forest in SW China.

    Science.gov (United States)

    Zhao, Mingxu; Geekiyanage, Nalaka; Xu, Jianchu; Khin, Myo Myo; Nurdiana, Dian Ridwan; Paudel, Ekananda; Harrison, Rhett Daniel

    2015-01-01

    Vascular epiphytes are an understudied and particularly important component of tropical forest ecosystems. However, owing to the difficulties of access, little is known about the properties of epiphyte-host tree communities and the factors structuring them, especially in Asia. We investigated factors structuring the vascular epiphyte-host community and its network properties in a tropical montane forest in Xishuangbanna, SW China. Vascular epiphytes were surveyed in six plots located in mature forests. Six host and four micro-site environmental factors were investigated. Epiphyte diversity was strongly correlated with host size (DBH, diameter at breast height), while within hosts the highest epiphyte diversity was in the middle canopy and epiphyte diversity was significantly higher in sites with canopy soil or a moss mat than on bare bark. DBH, elevation and stem height explained 22% of the total variation in the epiphyte species assemblage among hosts, and DBH was the most important factor which alone explained 6% of the variation. Within hosts, 51% of the variation in epiphyte assemblage composition was explained by canopy position and substrate, and the most important single factor was substrate which accounted for 16% of the variation. Analysis of network properties indicated that the epiphyte host community was highly nested, with a low level of epiphyte specialization, and an almost even interaction strength between epiphytes and host trees. Together, these results indicate that large trees harbor a substantial proportion of the epiphyte community in this forest.

  2. Climate change impacts on the water balance of coastal and montane rainforests in northern Queensland, Australia

    Science.gov (United States)

    Wallace, Jim; McJannet, Dave

    2012-12-01

    SummaryHow the water balance of coastal and montane rainforests in northern Queensland could change in response to climate change was examined using physically based models of interception and transpiration along with long term weather records. Future rainfall and temperature changes were based on the most recent climate modelling for the region and were assumed to fall within the range ±20% for rainfall with a temperature increase of 1-3 K. Climate change will affect the water balance of Australian rainforests primarily via rainfall changes rather than temperature. Any given change in rainfall produces a greater change in downstream runoff, the amplification ranging from 1.1 to 1.5 in the wet season to a factor of 12 in the dry season. Changes in wet season rainfall (80% of the annual total) dominate the total annual amount of water released for downstream flow, but dry season rainfall (20% of the annual total) changes are also very important as they affect onset and the duration of the period when there is no runoff. This period is currently ˜110 days and this would change by ±30 days under the above climate scenarios. There are also potential in situ impacts of climate change that affect how long the rainforest canopy is wet, which may have important implications for the epiphytes and mosses that depend on these wet canopy conditions. Similarly there may be significant impacts on downstream freshwater species whose life cycles are adapted to the current dry season flow regime.

  3. FLORISTIC CHANGES ALONG THE TOPOGRAPHICAL GRADIENT IN MONTANE GRASSLANDS IN MONTI PICENTINI (CAMPANIA, SW ITALY

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    F. SPADA

    2010-04-01

    Full Text Available Populations of xerotolerant species (Achnatherum calamagrostis, Stipa crassiculmis subsp. picentina, are scattered along a wide altitudinal gradient on slopes at mid- and high elevation in Monti Picentini, a subcoastal mesozoic limestone ridge in Tyrrhenian Southern Italy. Their stands are widespread in grasslands of mostly secondary origin. At lower altitudes these grasslands replace former deciduous forest communities dominated by oaks or beech, while at higher altitudes they reach the summits, where they apparently merge into the remnants of the still partially grazed, zonal climatogenic, grasslands ranging above the local tree-line. Nevertheless primary stands of these grasslands are to be found around the many clusters of highly dynamic sites of the montane and sub-alpine levels, scattered around screes and rocky outcrops of the prevalently dolomitic morphology of the slopes. This virtual continuity of non arboreal communities across more than 1000 metres of the local topographical gradient, where azonal, relic stands of Pinus nigra s.l. are transitional between the grasslands and the surrounding zonal broadleaved forest vegetation, stresses patterns of the coenological changes between Festuco-Brometea and Elyno-Seslerietea along the catena, which suggest fragmentary persistence of a paleozonation.

  4. FLORISTIC CHANGES ALONG THE TOPOGRAPHICAL GRADIENT IN MONTANE GRASSLANDS IN MONTI PICENTINI (CAMPANIA, SW ITALY

    Directory of Open Access Journals (Sweden)

    M. CUTINI

    2010-01-01

    Full Text Available Populations of xerotolerant species (Achnatherum calamagrostis, Stipa crassiculmis subsp. picentina, are scattered along a wide altitudinal gradient on slopes at mid- and high elevation in Monti Picentini, a subcoastal mesozoic limestone ridge in Tyrrhenian Southern Italy. Their stands are widespread in grasslands of mostly secondary origin. At lower altitudes these grasslands replace former deciduous forest communities dominated by oaks or beech, while at higher altitudes they reach the summits, where they apparently merge into the remnants of the still partially grazed, zonal climatogenic, grasslands ranging above the local tree-line. Nevertheless primary stands of these grasslands are to be found around the many clusters of highly dynamic sites of the montane and sub-alpine levels, scattered around screes and rocky outcrops of the prevalently dolomitic morphology of the slopes. This virtual continuity of non arboreal communities across more than 1000 metres of the local topographical gradient, where azonal, relic stands of Pinus nigra s.l. are transitional between the grasslands and the surrounding zonal broadleaved forest vegetation, stresses patterns of the coenological changes between Festuco-Brometea and Elyno-Seslerietea along the catena, which suggest fragmentary persistence of a paleozonation.

  5. Uranium delivery and uptake in a montane wetland, north-central Colorado, USA

    Science.gov (United States)

    Schumann, R. Randall; Zielinski, Robert A.; Otton, James K.; Pantea, Michael P.; Orem, William H.

    2017-01-01

    Comprehensive sampling of peat, underlying lakebed sediments, and coexisting waters of a naturally uraniferous montane wetland are combined with hydrologic measurements to define the important controls on uranium (U) supply and uptake. The major source of U to the wetland is groundwater flowing through locally fractured and faulted granite gneiss of Proterozoic age. Dissolved U concentrations in four springs and one seep ranged from 20 to 83 ppb (μg/l). Maximum U concentrations are ∼300 ppm (mg/kg) in lakebed sediments and >3000 ppm in peat. Uranium in lakebed sediments is primarily stratabound in the more organic-rich layers, but samples of similar organic content display variable U concentrations. Post-depositional modifications include variable additions of U delivered by groundwater. Uranium distribution in peat is heterogeneous and primarily controlled by proximity to groundwater-fed springs and seeps that act as local point sources of U, and by proximity to groundwater directed along the peat/lakebeds contact. Uranium is initially sorbed on various organic components of peat as oxidized U(VI) present in groundwater. Selective extractions indicate that the majority of sorbed U remains as the oxidized species despite reducing conditions that should favor formation of U(IV). Possible explanations are kinetic hindrances related to strong complex formation between uranyl and humic substances, inhibition of anaerobic bacterial activity by low supply of dissolved iron and sulfate, and by cold temperatures.

  6. Holocene fire and vegetation dynamics in a montane forest, North Cascade Range, Washington, USA

    Science.gov (United States)

    Prichard, Susan J.; Gedalof, Ze'ev; Oswald, W. Wyatt; Peterson, David L.

    2009-07-01

    We reconstructed a 10,500-yr fire and vegetation history of a montane site in the North Cascade Range, Washington State based on lake sediment charcoal, macrofossil and pollen records. High-resolution sampling and abundant macrofossils made it possible to analyze relationships between fire and vegetation. During the early Holocene (> 10,500 to ca. 8000 cal yr BP) forests were subalpine woodlands dominated by Pinus contorta. Around 8000 cal yr BP, P. contorta sharply declined in the macrofossil record. Shade tolerant, mesic species first appeared ca. 4500 cal yr BP. Cupressus nootkatensis appeared most recently at 2000 cal yr BP. Fire frequency varies throughout the record, with significantly shorter mean fire return intervals in the early Holocene than the mid and late Holocene. Charcoal peaks are significantly correlated with an initial increase in macrofossil accumulation rates followed by a decrease, likely corresponding to tree mortality following fire. Climate appears to be a key driver in vegetation and fire regimes over millennial time scales. Fire and other disturbances altered forest vegetation at shorter time scales, and vegetation may have mediated local fire regimes. For example, dominance of P. contorta in the early Holocene forests may have been reinforced by its susceptibility to frequent, stand-replacing fire events.

  7. Sap flow of Castanopsis jianfengensis and its relationship with environmental factors in a tropical montane rainforest

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Using thermal dissipation and the ICT-2000TE equipment made in Australia,the sap flow of Castanopsis jianfengensis and various environmental factors were measured simultaneously in a mixed tropical montane rainforest at Jianfengling Nature Forest Reserve (18°36'N,108°52'E,860 m elevation) during the dry and rainy seasons of 2002.The results show that sap flow velocity of C jianfengensis exhibited a monopeak pattern on clear days and a multi-peak pattern on cloudy or rainy days.Sap flow velocity had significant positive correlations with solar radiation,air temperature,vapor pressure deficit and wind speed and a negative correlation with air relative humidity.In the dry season,sap flow velocity had a significant positive correlation with soil temperature and poor correlation with soil moisture;it was the opposite in the rainy season,indicating that precipitation clearly affected sap flow.Linear regression models between sap flow and environmental factors were established and were significant at the 0.005 level of probability.The mean transpiration rates of C.jianfengensis were 103.5 and 41.3 kg/d in our single tree and 1.94 and 0.77 mm/d in stand level in the dry and rainy season,respectively.

  8. Can a fake fir tell the truth about Swiss needle cast?

    Science.gov (United States)

    A key question in dendrochronology to reconstruct forest disturbance history is how to distinguish between the effects of Swiss needle cast (SNC) and other forest disturbance agents (e.g., Douglas-fir beetle, tussock moth, western spruce budworm, laminated root rot, Armillaria ro...

  9. EuroFIR quality approach for managing food composition data; where are we in 2014?

    Science.gov (United States)

    Westenbrink, Susanne; Roe, Mark; Oseredczuk, Marine; Castanheira, Isabel; Finglas, Paul

    2016-02-15

    A EuroFIR quality management framework was developed to assure data quality of food composition data, incorporating several recommendations developed or improved during the EuroFIR projects. A flow chart of the compilation process with standard operating procedures to assure critical steps was the starting point. Recommendations for food description, component identification, value documentation, recipe calculation, quality evaluation of values, guidelines to assess analytical methods, document and data repositories and training opportunities were harmonized as elements of the quality framework. European food composition database organizations reached consensus on the EuroFIR quality framework and started implementation. Peer reviews of the European compiler organizations were organized to evaluate the quality framework, focusing on what was achieved and on improvements needed. The reviews demonstrated that European food database compilers have made good use of standards and guidelines produced by EuroFIR, as well as a common understanding that a quality framework is essential to assure food composition data quality. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Fungal endophytes in woody roots of Douglas-fir (Pseudotsuga menziesii) and ponderosa pine (Pinus ponderosa)

    Science.gov (United States)

    J. A. Hoff; Ned B. Klopfenstein; Geral I. McDonald; Jonalea R. Tonn; Mee-Sook Kim; Paul J. Zambino; Paul F. Hessburg; J. D. Rodgers; T. L. Peever; L. M. Carris

    2004-01-01

    The fungal community inhabiting large woody roots of healthy conifers has not been well documented. To provide more information about such communities, a survey was conducted using increment cores from the woody roots of symptomless Douglas-fir (Pseudotsuga menziesii) and ponderosa pine (Pinus ponderosa) growing in dry forests...

  11. Implementation of High Performance Fir Filter Using Low Power Multiplier and Adder

    Directory of Open Access Journals (Sweden)

    Sweety Kashyap,

    2014-01-01

    Full Text Available The ever increasing growth in laptop and portable systems in cellular networks has intensified the research efforts in low power microelectronics. Now a day, there are many portable applications requiring low power and high throughput than ever before. Thus, low power system design has become a significant performance goal. So this paper is face with more constraints: high speed, high throughput, and at the same time, consumes as minimal power as possible. The Finite Impulse Response (FIR Filter is the important component for designing an efficient digital signal processing system. So, in this paper author trying, a FIR filter is constructing, which is efficient not only in terms of power and speed but also in terms of delay. When consider the elementary structure of an FIR filter, it is found that it is a combination of multipliers and delays, which in turn are the combination of adders. . This paper presents an efficient implementation and analysis for performance evaluation of multiplier and adder to minimize the consumption of energy during multiplication and addition methodology to improve the performance by compares different type of Multipliers and adder, respectively. By using, power comparison result of adders and multiplier, choice low power adder and multiplier to implementation of high performance FIR filter.

  12. Implementation of High Speed FIR Filter: Performance Comparison with Different Parallel Prefix Adders in FPGAs

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    R. Uma

    2014-04-01

    Full Text Available This study describes the design of high speed FIR filter using parallel prefix adders and factorized multiplier. The fundamental component in constructing any high speed FIR filter consists of adders, multipliers and delay elements. To meet the constraint of high speed performance and low power consumption parallel prefix adders are more suitable. This study focus the design of new Parallel Prefix Adder (PPA and new multiplier cell called factorized multiplier with minimal depth algorithm and its functional characteristics is compared with the existing architecture in terms of delay and area. The performance evaluation of the proposed PPA and multiplier are examined for the bit sizes of 8, 16, 32 and 64. The coefficient of the filter is obtained through hamming window using MATLAB program. The proposed FIR filter using new PPA and factorized multiplier has been prototyped on XC3S1600EFG320 in Spartan-3E Platform using Integrated Synthesis Environment (ISE for 90 nm process. Nearly 14% of slice utilization and 34% of speed improvement has been obtained for FIR using new PPA and factorized multiplier.

  13. Efficacy of management tools for control of Pythium root rot of Douglas fir seedlings, 2010

    Science.gov (United States)

    This study investigated the efficacy of management tools for control of Pythium root rot of Douglas fir seedlings. This effort was conducted as part of the IR-4 Ornamental Horticulture program to evaluate fungicides and biopesticides for management of root, crown and stem rot of ornamental plants ca...

  14. Lumber-grade recovery from 110-year-old Douglas-fir thinnings.

    Science.gov (United States)

    Norman P. Worthington

    1955-01-01

    What lumber-grade and yield recovery is possible from thinnings in low Site III, 110-year-old, young-growth Douglas -fir stand? A lumber-grade recovery study of sawtimber cut in recent thinning experiments at the Wind River Experimental Forest, Skamania County, Washington, gives some idea of the answer. The thinning experiments were designed to determine increment and...

  15. A Design of 2L-Channel FIR Paraunitary Filter Banks with Complex Coefficients

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    An algorithm is proposed for the design of 2L-channel FIR paraunitary filter banks with complex coefficients to meet the requirement of processing complex signals. The filter designed with the algorithm has the property of near linear-phase. Thus, there is no more phase distortions introduced to the phase spectrum.

  16. Carbon Sequestration in Soils Affected by Douglas Fir Reforestation in Apennines (Northern Italy

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    Giampaolo Di Biase

    2015-12-01

    Full Text Available Douglas fir reforestation plays an important role in Italian forest because no indigenous conifer has similar characteristics of productivity and timber quality. Few studies on physicochemical properties of soils under Douglas fire are noticeable. The aim of this work is to evaluate the organic C stock into soils under Douglas fir plantation in different selected areas. The areas of study are located in the North Apennine (Italy; Corno alle Scale (COR, Vallombrosa (VAL, Mulino Mengoni (MEN, respectively are chosen for the presence of Douglas fir reforestation of 60 years old. Two soil profiles for each area have been open and described. The pH value decreased along the profile depth. The organic C amount in organic layers was higher in Val and Men pedons than that determined in COR one. Higher amount of organic C were detected in organo-mineral horizons of Co pedons, highlighting a rapid turnover of soil organic matter. The C stock calculated in the first 30 cm of soil showed that the higher C amount is stored in highest altitudes profiles (COR6 and VAL6 than the other. The soil are classified as Lithic Dystrudepts in the highest altitudes (COR 6, 7 and VAL 6, 7, respectively while as Humic Dystrudepts in MEN (4 and 5 pedons. We conclude that no dangerous effects on soil quality of Douglas fir were investigated and they seem to be similar to those of native tree species, even if other different aspects should be investigated.

  17. Realized gains from block-plot coastal Douglas-fir trials in the northern Oregon Cascades

    Science.gov (United States)

    Terrence Z. Ye; Keith J.S. Jayawickrama; J. Bradley. St. Clair

    2010-01-01

    Realized gains for coastal Douglas-fir (Pseudotsuga menziesii var. menziesii) were evaluated using data collected from 15-year-old trees from five field trials planted in large block plots in the northern Oregon Cascades. Three populations with different genetic levels (elite--high predicted gain; intermediate--moderate predicted gain; and an...

  18. Can a fake fir tell the truth about Swiss needle cast?

    Science.gov (United States)

    A key question in dendrochronology to reconstruct forest disturbance history is how to distinguish between the effects of Swiss needle cast (SNC) and other forest disturbance agents (e.g., Douglas-fir beetle, tussock moth, western spruce budworm, laminated root rot, Armillaria ro...

  19. Three different criteria for the design of two-dimensional zero phase FIR digital filters

    DEFF Research Database (Denmark)

    Gislason, E.; Johansen, M.; Conradsen, Knut

    1993-01-01

    An error criterion for the design of FIR filters is proposed. Filters with relatively many free filter coefficients are designed using the Chebyshev, the weighted-least-squares (WLS), and a new partitioned minimax error criterion, and the performance of the filters is compared. A general and fast...

  20. A Comparative Study on LUT and Accumulator Radix-4 Based Multichannel RNS FIR Filter Architectures

    Directory of Open Access Journals (Sweden)

    Britto Pari. J

    2014-05-01

    Full Text Available In this paper, a comparative study of two architectures proposed for multichannel reconfigurable FIR filter are performed in terms of complexity and speed. The proposed architectures, viz, dual port memory based LUT multiplier and accumulator based radix-4 multiplier architectures, are designed to reduce the complexity and to improve the speed of operation of multiplier used in multichannel reconfigurable FIR filter. Both the architectures accepts residues of given binary input in which the 3n-bit binary input is converted into three residues using binary to Residue Number System (RNS converter, and then processed in three FIR sub filters constructed in direct form. The reconfigurable structure is achieved by combining Power of Two (PoT FIR sub modules and altering the filter taps based on select signals. The proposed designs can be realized up to 20-taps and has been tested for 4, 8, 16 and 20 taps. The architectures have been realized in Verilog HDL and synthesized using Altera FPGA device Stratix II EP2S15F672C5. The performance comparison of two architectures shows that dual port memory based LUT multiplier architecture significantly reduces the area by 20% and accumulator based Radix-4 multiplier increases the speed by 90% regardless of the number of taps.

  1. Is long primary growth associated with stem sinuosity in Douglas-fir?

    Science.gov (United States)

    Barbara L. Gartner; G.R. Johnson

    2006-01-01

    Stem sinuosity is a highly visible stem-form trait in the leaders of fast-growing Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco) trees, yet its cause is unknown. We tested the hypotheses that sinuous stems have longer expanses of primary growth than nonsinuous stems (putting the leader at higher risk for...

  2. Impact of the foliar pathogen Swiss needle cast on wood quality of Douglas-fir.

    Science.gov (United States)

    G.R. Johnson; Amy T. Grotta; Barbara L. Gartner; Geoff. Downes

    2005-01-01

    Many stands of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) near coastal areas of Oregon and Washington are heavily infected with the foliar pathogen causing Swiss needle cast (SNC) disease, and yet there is very little research on the resulting wood quality. Modulus of elasticity(MOE), modulus of rupture (MOR), microfibril angle (MFA), wood...

  3. Dynamic phenotypic plasticity in photosynthesis and biomass patterns in Douglas-fir seedlings

    Science.gov (United States)

    A. C. Koehn; G. I. McDonald; D. L. Turner; D. L. Adams

    2010-01-01

    As climate changes, understanding the mechanisms long-lived conifers use to adapt becomes more important. Light gradients within a forest stand vary constantly with the changes in climate, and the minimum light required for survival plays a major role in plant community dynamics. This study focuses on the dynamic plasticity of Douglas-fir (Pseudotsuga menziesii var....

  4. The Douglas-Fir Genome Sequence Reveals Specialization of the Photosynthetic Apparatus in Pinaceae

    Directory of Open Access Journals (Sweden)

    David B. Neale

    2017-09-01

    Full Text Available A reference genome sequence for Pseudotsuga menziesii var. menziesii (Mirb. Franco (Coastal Douglas-fir is reported, thus providing a reference sequence for a third genus of the family Pinaceae. The contiguity and quality of the genome assembly far exceeds that of other conifer reference genome sequences (contig N50 = 44,136 bp and scaffold N50 = 340,704 bp. Incremental improvements in sequencing and assembly technologies are in part responsible for the higher quality reference genome, but it may also be due to a slightly lower exact repeat content in Douglas-fir vs. pine and spruce. Comparative genome annotation with angiosperm species reveals gene-family expansion and contraction in Douglas-fir and other conifers which may account for some of the major morphological and physiological differences between the two major plant groups. Notable differences in the size of the NDH-complex gene family and genes underlying the functional basis of shade tolerance/intolerance were observed. This reference genome sequence not only provides an important resource for Douglas-fir breeders and geneticists but also sheds additional light on the evolutionary processes that have led to the divergence of modern angiosperms from the more ancient gymnosperms.

  5. [Genetic control of Silver fir isozymes (Abies alba Mill.) of the Ukrainian Carpathian Mountains].

    Science.gov (United States)

    Korshikov, I I; Morozova, N N; Pirko, Ia V

    2003-01-01

    Genetic control of GOT, GDH, DIA, MDH, ME, SOD, FDH, ADH, ACP, LAP enzymes has been studied in the seed megagametophytes of Silver fir (Abies alba Mill.) from four natural populations of the Ukrainian Carpathian mountains. The distinct electrophoretic division has been obtained for the 21 loci products. The analysis of allele segregation in the heterozygous trees confirms monogenic inheritance of the revealed variants.

  6. EuroFIR eBASIS: application for health claims submissions and evaluations

    NARCIS (Netherlands)

    Kiely, M.; Black, L.J.; Plumb, J.; Kroon, P.; Hollman, P.C.H.; Larsen, J.C.; Speijers, G.; Kapsokefalou, M.; Sheehan, D.; Gry, J.; Finglas, P.M.

    2010-01-01

    Background: The European Food Information Resource (EuroFIR) network has established the eBASIS (Bioactive Substances in Food Information System) online food composition and biological effects database for plant-derived bioactive compounds (phytochemicals). On the basis of submitted evidence, the Eu

  7. Effects of Different Types of Chinese Fir Stands on Nutrient Status of Soils

    Institute of Scientific and Technical Information of China (English)

    YUYUAN-CHUN; ZHANGHUAN-CHAO

    1995-01-01

    The effects of different types of Chinese fir stand,including those with varous composition (pure and mixed),in various cropping systems (first and continuous cropping system)and at different ages,on the nutrient status of soils the hilly regions of southern Anhui Province were studied by means of ecological sequential comparison on the basis of similar climate and soil type.The work was carried out in the Xiaoxi Forest Farm of Jingxian County and the Caijiaqiao Forest Farm of Jingde Coundy,where the soil is parayellow soil derived from phyllite and sandstone,The results revealed that with the increase of age,Chinese fir pure stand could accumulate organic matter and nitrogen in the soil but it resulted in decreasing of soil pH and base ions(especially Ca2+) compared to its mixed stand with broad-leaf trees such as Chinese sassafras,In order to improve the soil fertility,It would be better to mix Chinese fir with broad-leaf trees when afforestation In the management of Chinese fir pure stand,base compounds and phosphates should be added to the soil for mintaining soil fertility and raising and raising forest productivity.

  8. Training aspects in the use and production of food composition databases. The EuroFIR experience.

    NARCIS (Netherlands)

    Hollman, P.C.H.; Witthöft, C.; Busstra, M.C.; Elburg, L.; Hulshof, P.J.M.

    2009-01-01

    An increasing number of national food databases have been published on the internet. However, these internet databases can only be searched individually, and the data have been compiled at a national level, resulting in incompatibilities. To resolve these problems, the Network of Excellence EuroFIR

  9. Provenance variation in subalpine fir grown as an exotic tree species in Denmark and Iceland

    DEFF Research Database (Denmark)

    Skúlason, Brynjar

    Neonectria neomacrospora in Denmark. In Iceland the corkbark fir showed superior results, especially for survival rate and Christmas tree quality. The White River provenance from British Columbia is recommended for use in Denmark. The Mount Taylor provenance from the Cibola National Forest in New Mexico...

  10. Frequency invariant beamforming via optimal array pattern synthesis and FIR filters design

    Institute of Scientific and Technical Information of China (English)

    YAN Shefeng; MA Yuanliang

    2005-01-01

    An approach to designing time domain broadband frequency invariant beamformer via optimal array pattern synthesis and optimal FIR filters design is proposed. First, the working frequency band is decomposed into a number of narrow band frequency bins. The array weights at each frequency bin are designed via optimal array pattern synthesis methods to insure that the synthesized pattern approximates the desired one within the mainlobe area.Then, a bank of FIR filters corresponding to the input channels are designed to provide the frequency responses that approximate the array weights in the working frequency band for each sensor. Finally, each sensor feeds a FIR filter and the filter outputs are summed to produce the beam output time series. Both array pattern synthesis and FIR filters design problems are formulated as the second-order cone programming (SOCP), which can be easily solved using well-developed interior-point methods. Results of computer simulations and lake-experiment for a twelve-element semicircular array demonstrate satisfactory performance of the proposed approach.

  11. High-angular resolution observations towards OMC-2 FIR 4: Dissecting an intermediate-mass protocluster

    NARCIS (Netherlands)

    A. López-Sepulcre; V. Taquet; A. Sánchez-Monge; C. Ceccarelli; C. Dominik; M. Kama; E. Caux; F. Fontani; A. Fuente; P.T.P. Ho; R. Neri; Y. Shimajiri

    2013-01-01

    Context. Intermediate-mass stars are an important ingredient of our Galaxy and a key to understanding how high- and low-mass stars form in clusters. One of the closest known young intermediate-mass protoclusters is OMC-2 FIR 4, which is located at a distance of 420 pc in Orion. This region is one of

  12. Effects of heat treatment on some physical properties of Douglas fir (Pseudotsuga menziesii) wood

    Science.gov (United States)

    Xianjun Li; Zhiyong Cai; Qunying Mou; Yiqiang Wu; Yuan Liu

    2011-01-01

    In this study the effect of heat treatment on some physical properties of Douglas fir (Pseudotsuga menziesii) was investigated. Wood specimens were subjected to heat treatment at 160, 180, 200 and 220°C for 1, 2, 3 and 4h. The results show that heat treatment resulted in a darkened color, decreased moisture performance and increased dimensional stability of...

  13. Assessing the specific energy consumption and physical properties of comminuted Douglas-fir chips for bioconversion

    Science.gov (United States)

    Yalan Liu; Jinwu Wang; Michael P. Wolcott

    2016-01-01

    Size reduction homogenizes the bulk biomass and facilitates downstream feedstock handling, transportation, and storage. Effects of feeding rate, mill-type (hammer and knife mill), screen size, and moisture content on comminution energy consumption of commercial Douglas-fir (Pseudotsuga menziesii) pulp chips were quantified. The resulting particles...

  14. Growth and nutrition of Douglas fir, Scots pine and pedunculate oak in relation to soil acidification.

    NARCIS (Netherlands)

    Visser, de P.H.B.

    1994-01-01

    In a Douglas fir ( Pseudotsuga menziesii (Mirb.) Franco) and in a Scots pine ( Pinus sylvestris L.) stand on sandy soil in the Netherlands, inputs of water, nutrients and acid loads were changed for four years. Effects of soil changes on growth and nutrition were compared with similar foreign experi

  15. Growth and morphogenesis of shoot initials of Douglas fir, Pseudotsuga menziesii (Mirb.) Franco, in vitro

    NARCIS (Netherlands)

    Evers, P.W.

    1984-01-01

    An optimalized method of micropropagation of Douglas fir is described. Seasonal changes were found in optima for nitrate and sucrose in the medium and in the optimum for the light intensity during the culture of shoot initials. Differences in morphogenesis were obtained from shoot initials that had

  16. Simulation of carbon and water budgets of a Douglas-fir forest

    NARCIS (Netherlands)

    Wijk, van M.T.; Dekker, S.C.; Bouten, W.; Kohsiek, W.; Mohren, G.M.J.

    2001-01-01

    The forest growth/hydrology model FORGRO–SWIF, consisting of a forest growth and a soil water model, was applied to quantify the inter-annual variability of the carbon and water budgets of a Douglas-fir forest (Pseudotsuga menziessii (Mirb.) Franco) in The Netherlands. With these budgets, the water

  17. Establishment and growth of native hardwood and conifer seedlings underplanted in thinned Douglas-fir stands.

    Science.gov (United States)

    Kathleen G. Maas-Hebner; William H. Emmingham; David L. Larson; Samuel S. Chan

    2005-01-01

    Five conifers and two hardwoods native to the Pacific Northwest were planted under four overstory densities of 30-year-old plantations of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) in the Oregon Coast Range, USA. Stand treatments were unthinned (547 trees ha-1), narrow thin (252 trees ha-1),...

  18. Effect of Mixed Forests of Chinese Fir and Tsoong‘s Tree on Soil Properties

    Institute of Scientific and Technical Information of China (English)

    ZHENGYUSHAN; DINGYINGXIANG

    1998-01-01

    An investigation and on 13-year-old(1984-1996) Chinese fir and Tsoong's tree mixed forests in Jianou City,Fujian Province,China was carried out to compare the influences of different interplanting types of individual tree-tree,row-row,row-strip(three rows)and pure Chinese fir stands on soil properties.Compared with the pure stands of Chinese fir ,the mixed stands exerted a posivtive effect on soil fertility,with increases in soil organic matter,total N,available P and available K.Moreover,improvements were also observed in soil enzymatic activities ,aggregate structure,structure,stability,status of soil porosity,soil aeration and penetrability in miexd stands.The row-row interplanted stands had the best effect on tree growth and soil properties among these mixed forests.In the southern subtropical region,the spreading of the row-row mixing model of the two tree species would be helpful to preventin ghe soil from fertility deterioratio caused by successive plantation of Chineses fir.

  19. Photosynthetic capacity of tropical montane tree species in relation to leaf nutrients, successional strategy and growth temperature.

    Science.gov (United States)

    Dusenge, Mirindi Eric; Wallin, Göran; Gårdesten, Johanna; Niyonzima, Felix; Adolfsson, Lisa; Nsabimana, Donat; Uddling, Johan

    2015-04-01

    Photosynthetic capacity of tree leaves is typically positively related to nutrient content and little affected by changes in growth temperature. These relationships are, however, often poorly supported for tropical trees, for which interspecific differences may be more strongly controlled by within-leaf nutrient allocation than by absolute leaf nutrient content, and little is known regarding photosynthetic acclimation to temperature. To explore the influence of leaf nutrient status, successional strategy and growth temperature on the photosynthetic capacity of tropical trees, we collected data on photosynthetic, chemical and morphological leaf traits of ten tree species in Rwanda. Seven species were studied in a forest plantation at mid-altitude (~1,700 m), whereas six species were studied in a cooler montane rainforest at higher altitude (~2,500 m). Three species were common to both sites, and, in the montane rainforest, three pioneer species and three climax species were investigated. Across species, interspecific variation in photosynthetic capacity was not related to leaf nutrient content. Instead, this variation was related to differences in within-leaf nitrogen allocation, with a tradeoff between investments into compounds related to photosynthetic capacity (higher in pioneer species) versus light-harvesting compounds (higher in climax species). Photosynthetic capacity was significantly lower at the warmer site at 1,700 m altitude. We conclude that (1) within-leaf nutrient allocation is more important than leaf nutrient content per se in controlling interspecific variation in photosynthetic capacity among tree species in tropical Rwanda, and that (2) tropical montane rainforest species exhibit decreased photosynthetic capacity when grown in a warmer environment.

  20. Nine thousand years of upper montane soil/vegetation dynamics from the summit of Caratuva Peak, Southern Brazil

    Science.gov (United States)

    Scheer, Maurício B.; Pereira, Nuno Veríssimo; Behling, Hermann; Curcio, Gustavo R.; Roderjan, Carlos V.

    2014-12-01

    Biodiversity loss, climate change, and increased freshwater consumption are some of the main environmental problems on Earth. Mountain ecosystems can reduce these threats by providing several positive influences, such as the maintenance of biodiversity, water regulation, and carbon storage, amongst others. The knowledge of the history of these environments and their response to climate change is very important for management, conservation, and environmental monitoring programs. The genesis of the soil organic matter of the current upper montane vegetation remains unclear and seems to be quite variable depending on location. Some upper montane sites in the very extensive coastal Sea Mountain Range present considerable organic matter from the late Pleistocene and other from only the Holocene. Our study was carried out on three soil profiles (two cores in grassland and one in forest) on the Caratuva Peak of the Serra do Ibitiraquire (a sub-range of Sea Mountain Range - Serra do Mar) in Southern Brazil. The δ13C isotopic analyses of organic matter in soil horizons were conducted to detect whether C3 or C4 plants dominated the past communities. Complementarily, we performed a pollen analysis and 14C dating of the humin fraction to obtain the age of the studied horizons. Except for a short and probably drier period (between 6000 and 4500 cal yr BP), C3 plants, including ombrophilous grasses and trees, have dominated the highlands of the Caratuva Peak (Pico Caratuva), as well as the other uppermost summits of the Serra do Ibitiraquire, since around 9000 cal yr BP. The Caratuva region represents a landscape of high altitude grasslands (campos de altitude altomontanos or campos altomontanos) and upper montane rain/cloud forests with soils that most likely contain some organic matter from the late Pleistocene, as has been reported in Southern and Southeastern Brazil for other sites. However, our results indicate that the studied deposits (near the summit) are from the early

  1. Lluís Domènech i Montaner, a la recerca de la ceràmica moderna

    OpenAIRE

    Casanova, Rossend

    2002-01-01

    El 1887, Lluís Doménech i Montaner va rebre l’encàrrec de projectar i construir el Café-Restaurant de l’Exposició Universal de Barcelona de 1888, el que seria l’edifici més rellevant de la seva primera etapa com arquitecte. El resultat fou un edifici estructuralment gran, visualment admirable i arquitectònicament modern, en el que la ceràmica aplicada havia de tenir un gran protagonisme.

  2. Characterizing the Source Water for Montane Meadows to Assess Resiliency under Changing Hydroclimatic Condition

    Science.gov (United States)

    Yarnell, S. M.; Peek, R.; Bell, A.; Weixelman, D.; Viers, J. H.

    2015-12-01

    Ecologically and hydrologically functioning montane meadows provide a variety of ecosystem services and create biological hotspots in high-elevation landscapes. They serve as wetlands that filter water, attenuate floods, sequester carbon, sustain downstream flows, and provide high productivity habitat in typically lower productivity mountain regions. Their importance to watershed quality and health is well recognized, and restoration of meadows is a high priority for resource management agencies and non-governmental organizations. Yet many meadow restoration projects have limited outcomes or fail to achieve the desired effects due to a lack of understanding the underlying hydrological and geomorphic processes inherent to meadows that contribute to their resiliency. Few studies exist on how meadows are sustained through time despite various land use impacts or how the origin of water supplying the meadow (snowmelt-dominated versus regional groundwater-dominated) may influence meadow conditions. Furthermore, as climate conditions continue to change, questions remain regarding which meadows will be most resistant to and resilient from climate warming and thus have the highest potential for successful and sustainable restoration of meadow processes. We discuss these concepts and present two methods for assessing the regional and local contributions of source water to meadows as an indicator of resiliency. On a broad scale, comparisons of satellite imagery using metrics such as normalized difference vegetation index (NDVI) for regions with meadows may be useful to detect inter-annual and seasonal variations in meadow wetness and thus indicate meadow sites with larger groundwater sources that are more resilient over time. Locally, use of a hydrogeomorphic typing key that relates water source, geomorphic position, groundwater table elevation, and plant species composition may be useful to detect local groundwater sources that provide greater consistency of conditions and

  3. Dissolved organic matter transport reflects hillslope to stream connectivity during snowmelt in a montane catchment

    Science.gov (United States)

    Burns, Margaret A.; Barnard, Holly R.; Gabor, Rachel S.; McKnight, Diane M.; Brooks, Paul D.

    2016-06-01

    Dissolved organic matter (DOM) transport is a key biogeochemical linkage across the terrestrial-aquatic interface in headwater catchments, and quantifying the biological and hydrological controls on DOM composition provides insight into DOM cycling at the catchment scale. We evaluated the mobility of DOM components during snowmelt in a montane, semiarid catchment. DOM composition was evaluated on a near-daily basis within the soil and the stream during snowmelt, and was compared to groundwater samples using a site-specific parallel factor analysis (PARAFAC) model derived from soil extracts. The fluorescent component loadings in the interstitial soil water and in the groundwater were significantly different and did not temporally change during snowmelt. In the stream, a transition occurred during snowmelt from fluorescent DOM with higher contributions of amino acid-like components indicative of groundwater to higher humic-like contributions indicative of soil water. Furthermore, we identified a humic-like fluorescent component in the soil water and the stream that is typically only observed in extracted water soluble organic matter from soil which may suggest hillslope to stream connectivity over very short time scales. Qualitative interpretations of changes in stream fluorescent DOM were supported by two end-member mixing analyses of conservative tracers. After normalizing fluorescent DOM loadings for dissolved organic carbon (DOC) concentration, we found that the peak in DOC concentration in the stream was driven by the nonfluorescent fraction of DOM. This study demonstrated how PARAFAC analysis can be used to refine our conceptual models of runoff generation sources, as well as provide a more detailed understanding of stream chemistry dynamics.

  4. Microbial carbon mineralization in tropical lowland and montane forest soils of Peru

    Directory of Open Access Journals (Sweden)

    Jeanette eWhitaker

    2014-12-01

    Full Text Available Climate change is affecting the amount and complexity of plant inputs to tropical forest soils. This is likely to influence the carbon (C balance of these ecosystems by altering decomposition processes e.g. ‘positive priming effects’ that accelerate soil organic matter mineralization. However, the mechanisms determining the magnitude of priming effects are poorly understood. We investigated potential mechanisms by adding 13C labelled substrates, as surrogates of plant inputs, to soils from an elevation gradient of tropical lowland and montane forests. We hypothesised that priming effects would increase with elevation due to increasing microbial nitrogen limitation, and that microbial community composition would strongly influence the magnitude of priming effects. Quantifying the sources of respired C (substrate or soil organic matter in response to substrate addition revealed no consistent patterns in priming effects with elevation. Instead we found that substrate quality (complexity and nitrogen content was the dominant factor controlling priming effects. For example a nitrogenous substrate induced a large increase in soil organic matter mineralization whilst a complex C substrate caused negligible change. Differences in the functional capacity of specific microbial groups, rather than microbial community composition per se, were responsible for these substrate-driven differences in priming effects. Our findings suggest that the microbial pathways by which plant inputs and soil organic matter are mineralized are determined primarily by the quality of plant inputs and the functional capacity of microbial taxa, rather than the abiotic properties of the soil. Changes in the complexity and stoichiometry of plant inputs to soil in response to climate change may therefore be important in regulating soil C dynamics in tropical forest soils.

  5. Transpiration of shrub species, Alnus firma under changing atmospheric environments in montane area, Japan

    Science.gov (United States)

    Miyazawa, Y.; Maruyama, A.; Inoue, A.

    2014-12-01

    In the large caldera of Mt. Aso in Japan, grasslands have been traditionally managed by the farmers. Due to changes in the social structure of the region, a large area of the grassland has been abandoned and was invaded by the shrubs with different hydrological and ecophysiological traits. Ecophysiological traits and their responses to seasonally changing environments are fundamental to project the transpiration rates under changing air and soil water environments, but less is understood. We measured the tree- and leaf-level ecophysiological traits of a shrub, Alnus firma in montane region where both rainfall and soil water content drastically changes seasonally. Sap flux reached the annual peak in evaporative summer (July-August) both in 2013 and 2014, although the duration was limited within a short period due to the prolonged rainy season before summer (2014) and rapid decrease in the air vapor pressure deficit (D) in late summer. Leaf ecophysiological traits in close relationship with gas exchange showed modest seasonal changes and the values were kept at relatively high levels typical in plants with nitrogen fixation under nutrient-poor environments. Stomatal conductance, which was measured at leaf-level measurements and sap flux measurements, showed responses to D, which coincided with the theoretical response for isohydric leaves. A multilayer model, which estimates stand-level transpiration by scaling up the leaf-level data, successfully captured the temporal trends in sap flux, suggesting that major processes were incorporated. Thus, ecophysiological traits of A. firma were characterized by the absence of responses to seasonally changing environments and the transpiration rate was the function of the interannually variable environmental conditions.

  6. Climate forcing of an emerging pathogenic fungus across a montane multi-host community.

    Science.gov (United States)

    Clare, Frances C; Halder, Julia B; Daniel, Olivia; Bielby, Jon; Semenov, Mikhail A; Jombart, Thibaut; Loyau, Adeline; Schmeller, Dirk S; Cunningham, Andrew A; Rowcliffe, Marcus; Garner, Trenton W J; Bosch, Jaime; Fisher, Matthew C

    2016-12-05

    Changes in the timings of seasonality as a result of anthropogenic climate change are predicted to occur over the coming decades. While this is expected to have widespread impacts on the dynamics of infectious disease through environmental forcing, empirical data are lacking. Here, we investigated whether seasonality, specifically the timing of spring ice-thaw, affected susceptibility to infection by the emerging pathogenic fungus Batrachochytrium dendrobatidis (Bd) across a montane community of amphibians that are suffering declines and extirpations as a consequence of this infection. We found a robust temporal association between the timing of the spring thaw and Bd infection in two host species, where we show that an early onset of spring forced high prevalences of infection. A third highly susceptible species (the midwife toad, Alytes obstetricans) maintained a high prevalence of infection independent of time of spring thaw. Our data show that perennially overwintering midwife toad larvae may act as a year-round reservoir of infection with variation in time of spring thaw determining the extent to which infection spills over into sympatric species. We used future temperature projections based on global climate models to demonstrate that the timing of spring thaw in this region will advance markedly by the 2050s, indicating that climate change will further force the severity of infection. Our findings on the effect of annual variability on multi-host infection dynamics show that the community-level impact of fungal infectious disease on biodiversity will need to be re-evaluated in the face of climate change.This article is part of the themed issue 'Tackling emerging fungal threats to animal health, food security and ecosystem resilience'. © 2016 The Authors.

  7. Hydrology and human behavior: two key factors of diarrhea incidence in montane tropical humid areas

    Science.gov (United States)

    Boithias, Laurie; Choisy, Marc; Souliyaseng, Noy; Jourdren, Marine; Quet, Fabrice; Buisson, Yves; Thammahacksa, Chanthamousone; Silvera, Norbert; Latsachack, Keooudone; Sengtaheuanghoung, Oloth; Pierret, Alain; Rochelle-Newall, Emma; Becerra, Sylvia; Ribolzi, Olivier

    2017-04-01

    The global burden of diarrhea is a leading cause of morbidity and mortality worldwide. In montane areas of South-East Asia such as northern Laos, recent changes in land use have induced increased runoff, soil erosion and in-stream suspended sediment loads, and potential pathogen dissemination. In this study we hypothesized that climate factors combined with human behavior control diarrhea incidence, either because higher rainfall, leading to higher stream discharges, suspended sediment loads and Fecal Indicator Bacteria (FIB) counts, are associated with higher numbers of reported diarrhea cases during the rainy season, or because water shortage leads to the use of less safe water sources during the dry season. For this mixed methods approach, we conducted a retrospective time series analysis of meteorological variables (rainfall, air temperature), hydrological variables (discharge, suspended sediments, FIB counts, water temperature) at the outlet of 2 catchments in Northern Lao PDR, and the number of diarrheal disease cases reported in 6 health centers located in the Luang Prabang Province. We also examined the socio-behavioral factors potentially affecting vulnerability to the effect of the climate factors, such as drinking water sources and hygiene habits. We found the FIB Escherichia coli to be present all year long (100-1,000 MPN 100 mL-1) indicating that fecal contamination is ubiquitous and constant. We found that populations switch their water supply from wells to surface water during drought periods, the latter of which appear to be at higher risk of bacterial contamination than municipal water fountains. We thus found that water shortage in the Luang Prabang area triggers diarrhea peaks during the dry and hot season and that rainfall and aquifer refill ends the epidemic during the wet season. We thus found that anthropogenic drivers, such as hygiene practices, were at least as important as environmental drivers in determining the seasonal pattern of a

  8. Primary succession of Hawaiian montane rain forest on a chronosequence of eight lava flows

    Energy Technology Data Exchange (ETDEWEB)

    Kitayama, K.; Mueller-Dombois, D. [Univ. of Hawaii at Manoa, Honolulu, HI, (United States) Dept. of Botany; Vitousek, P.M. [Stanford Univ., Stanford, CA (United States) Dept. of Biological Sciences

    1995-04-01

    The primary-successional sere of a Hawaiian montane rain forest was inferred from an age sequence of eight closely located `a`a flows (clinker type lava); 8, 50, 140, ca. 300, ca. 400, ca. 1400, ca. 3000 and ca.9000 yr, on a windward slope of Mauna Loa, Hawaii. All study sites (0.2 ha each) were at 1120-1250 m a.s.l. with 4000 mm mean annual rainfall. The 400-yr, 1400-yr, and 9000-yr flows had younger volcanic ash deposits, while the others were pure lava. Comparisons of tree size and foliar nutrients suggested that ash increased the availability of nitrogen, and subsequently standing biomass. An Unweighted Pair Group Cluster Analysis on the samples (flows) using quantitative vascular species composition revealed that clusters were correlated with age regardless of the substrate types (pure lava vs. ash), and an indirect ordination on the samples suggested that the sequence of sample scores along axis 1 was perfectly correlated with the age sequence. Although ash deposits increased biomass, they did not affect the sequence of the successional sere. Both pubescent and glabrous varieties of Metrosideros polymorpha (Myrtaceae) dominated upper canopy layers on all flows {>=} 50 yr and {<=} 1400 yr, but the pubescent variety was replaced by the glabrous on the flows {>=} 3000 yr. Lower layers were dominated initially by a mated fern, Dicranopteris linearis, up to 300 yr, and subsequently by tree ferns, Cibotium spp., to 9000 yr. The cover of Cibotium declined sightly after 3000 yr, while other native herb and shrub species increased. 43 refs, 7 figs, 4 tabs

  9. Estimation of fog deposition on epiphytic bryophytes in a subtropical montane forest ecosystem in northeastern Taiwan

    Science.gov (United States)

    Chang, Shih-Chieh; Lai, I.-Ling; Wu, Jiunn-Tzong

    The fog meteorology, fog chemistry and fog deposition on epiphytic bryophytes were investigated from July 2000 to June 2001 in the Yuanyang Lake forest ecosystem. The elevation of the site ranges from 1650 to 2420 m, at which the high frequency of fog occurrence throughout the year has been thought to be of benefit to the establishment of the primary Taiwan yellow cypress forest [ Chamaecyparis obtusa var. formosana (Hayata) Rehder] and to the extensive growth of the epiphytic bryophytes. A weather station including a visibility sensor and an active fog collector was installed for fog meteorological and chemical study. The fog deposition rate on epiphytic bryophytes was estimated by measuring the increase rate in plant weight when exposed to fog. Average fog duration of 4.7 and 11.0 h per day was measured in summer months (June to August) and the rest of the year, respectively. November 2000 was the foggiest month in which the average fog duration reached 14.9 h per day. The ionic composition of fog water revealed that the area was less polluted than expected from literature data. The in situ exposure experiments done with the dominant epiphytic bryophytes showed an average fog deposition rate of 0.63 g H 2O g -1 d. w. h -1, which approximated 0.17 mm h -1 at the stand scale. The nutrient fluxes estimated for February 2001 showed that for all ions, more than 50% of the ecosystem input was through fog deposition. These results demonstrate the importance of epiphytic bryophytes and fog deposition in nutrient cycling of this subtropical montane forest ecosystem. The incorporation of fog study in the long-term ecosystem research projects is necessary in this area.

  10. Seed predation, disease and germination on landslides in Neotropical lower montane wet forest

    Energy Technology Data Exchange (ETDEWEB)

    Myster, R.W. [Puerto Rico Univ., San Juan (Puerto Rico). Inst. for Tropical Ecosystem Studies

    1997-02-01

    Seed mortality (caused by predators and pathogens) and germination were compared between Puerto Rico and Costa Rica on landslides in lower montane wet forest. Seeds of six common species on five Puerto Rican landslides and four common species on two Costa Rican landslides were used with a Cecropia species and a Gonzalagunia species included at both sites. In the Puerto Rican experiments Cecropia schreberiana was the only species to show significant seed predation (which was due to insects), pathogens grew from all species and fewer seeds were lost to predators than pathogens. Also in Puerto Rico mean germination across all species was 57% before dispersal (filled seeds collected while still on the tree) and 71% after, with Phytolacca rivinoides seeds germinating most abundantly, followed in descending order by Ocotea leucoxylon, Cecropia spec., Miconia racemosa, Palicourea riparia and Gonzalagunia spicata. In the Costa Rican experiments three species had significant predation: Cecropia polyphlebia and Urera caracasana (both due to insects) and Witheringia coccoloboides (due to mammals); pathogenic disease caused more seed loss than predation, and germination was high (61% pre-dispersal, 69% post-dispersal). Similarities between these island and mainland sites included (1) percentage of seeds lost to predation and percentage lost to pathogens (all in the 5-15% range), (2) generalist pathogens which claimed more seeds than predators and (3) majority germination with a general increase after dispersal. Finally sites were dissimilar only in the number of species with significant predation loss and whether it was by insects or mammals, casting doubt on the traditional island/mainland dichotomy. 62 refs, 3 figs, 2 tabs

  11. Coupling channel hydro-morphodynamics and fish spawning habitat in a forested montane stream

    Science.gov (United States)

    Cienciala, P.; Hassan, M. A.

    2011-12-01

    In this paper we couple a hydrodynamic model with field data to investigate channel dynamics and spawning habitat potential for small-bodied salmonids in coarse-bed streams in British Columbia. We studied four reaches of East Creek, a small montane stream near Vancouver, BC, which display rapid (plane bed) and riffle-pool morphologies and provide habitat for a population of resident coastal cutthroat trout. Repeated channel surveys were conducted to obtain detailed information on channel topography and dynamics; net change in bed elevation between successive surveys was utilized as an index of scour and fill. Extensive bed surface sampling and low altitude vertical imagery were used in order to investigate bed surface texture and structures and to identify suitable spawning substrate patches. A 2-D hydrodynamic model, FaSTMECH (within MultiDimensional Surface Water Modeling System interface), was calibrated using field data and applied to simulate the spatial pattern of bed shear stress during a bankfull flow event. During small-to-intermediate floods significant bed scour, deeper than the estimated egg burial depth, occurred on a small proportion of bed area, in well-defined zones associated with obstacles such as large woody debris. Usually, distinct depositional zones developed just downstream of the scour locations. The spatial distribution of forcing elements and modeled bed shear stress explained well the observed pattern of scour and fill. Suitable spawning gravel was very limited in the study sites, particularly in two upstream reaches, primarily due to the coarse nature of the bed. In summary, scour disturbance risk appears to be relatively low in coarse-bed channels, except during extreme flow events, and shortage of suitable spawning substrate may be more important for small-bodied salmonids. This study demonstrates that coupling of hydro-morphodynamic and ecological data can provide a useful tool in fish habitat assessment and restoration.

  12. Impact of Mining Activity upon Environment in Roşia Montană

    Directory of Open Access Journals (Sweden)

    SIGISMUND DUMA

    2008-01-01

    Full Text Available Roşia Montană is the greatest gold ore in Romania and one of the greatest in Europe, and its exploitation has been carried out since Antiquity up to nowadays. If the traditional extraction and processing technologies had a minimal impact upon environment, the ones adopted in modern times have affected all the components of the natural environment. In the perspective of capitalizing the gold ore through the programme elaborated by the Canadian company, Gold Corporation, the zonal geographical space will be degraded up to the level of industrial dessert over an area of 100 km2 and in case of damage, the affected area can extend enormously. The environmental problems are related both to the specific nature of such an industrial activity and, especially, to the use of enormous quantities of sodium cyanide directly on the preparation flux from the industrial plant. Few such cases are known worldwide, in several economically less developed countries. Usually, cyanides are used for treating the gold concentrations, operation done in conditions of maximum security, in closed spaces, situated in isolated zones and the neutralization (detoxification of cyanides is done in situ. The treatment of cyanides in open spaces has always generated environmental problems. Moreover, none of the cyanide treatment technologies eliminates entirely their toxic effect (less toxic chemical products are obtained. In order to avoid the production of an environmental disaster and to preserve the local patrimony values (in this place there lies the richest mining archeological site in Europe, we elaborated several recommendations we consider feasible as they allow both the capitalization of ore, which is a socio-economic necessity of the area, and the ecological reconstruction of the affected geographical space.

  13. Tropical montane cloud forests: current threats and opportunities for their conservation and sustainable management in Mexico.

    Science.gov (United States)

    Toledo-Aceves, Tarin; Meave, Jorge A; González-Espinosa, Mario; Ramírez-Marcial, Neptalí

    2011-03-01

    Tropical montane cloud forests (TMCF) are among the most threatened ecosystems globally in spite of their high strategic value for sustainable development due to the key role played by these forests in hydrological cycle maintenance and as reservoirs of endemic biodiversity. Resources for effective conservation and management programs are rarely sufficient, and criteria must be applied to prioritize TMCF for conservation action. This paper reports a priority analysis of the 13 main regions of TMCF distribution in Mexico, based on four criteria: (1) forest quality, (2) threats to forest permanence, (3) threats to forest integrity, and (4) opportunities for conservation. Due to the diverse socio-environmental conditions of the local communities living in Mexican TMCF regions, their associated social characteristics were also evaluated to provide a background for the planning of conservation actions. A set of indicators was defined for the measurement of each criterion. To assign priority values for subregions within each main region, an international team of 40 participants evaluated all the indicators using multicriteria decision-making analysis. This procedure enabled the identification of 15 subregions of critical priority, 17 of high priority, and 10 of medium priority; three more were not analysed due to lack of information. The evaluation revealed a number of subjects that had hitherto been undetected and that may prove useful for prioritization efforts in other regions where TMCF is similarly documented and faces equally severe threats. Based on this analysis, key recommendations are outlined to advance conservation objectives in those TMCF areas that are subjected to high pressure on forest resources. Copyright © 2010 Elsevier Ltd. All rights reserved.

  14. Camera trap survey of medium and large mammals in a montane rainforest of northern Peru

    Directory of Open Access Journals (Sweden)

    Carlos F. Jiménez

    2011-05-01

    Full Text Available Camera traps are a powerful tool for inventorying elusive and rare species and very useful to obtain ecologi- cal data for plans that involve wildlife conservation. In Peru, several surveys have been carried out in lowland Amazonia especially in the southeastern part of the country, but none in montane cloud forests or Yungas. We present the first camera trap studies produced in Peruvian Yungas at the locality of Querocoto village (Chota, Cajamarca, based on 2002 (dry season and 1264 (wet season camera traps-days (CTD. Two localities were surveyed in wet and dry season: The Pagaibamba Protection Forest and the San Lorenzo Forest. The wet season study was carried out in October and November, and the dry season in July to September of 2008. Eight mammalian species were recorded in both seasons. Some 66 (91.7% independent records were obtained in the dry season, but only six (8.3% in the wet one, suggesting a seasonality effect. The Mountain Paca Cunicu- lus taczanowskii was the most commonly photographed species, with 17.0 and 1.6 capture frequencies (dry and wet season respectively, whereas the Long-tailed weasel Mustela frenata (0.5 capture frequency in the dry season was the most rare species. Activity patterns suggest that Mountain Paca C. taczanowskii and the Andean Skunk C. chinga are nocturnal, while Spectacled Bear T. ornatus and Tayra E. barbara are diurnal in the study area. Our records of the Ocelot Leopardus pardalis and the Tayra E. barbara are among the highest altitudinal records known for each species. In addition, the Anta Tapirus pinchaque was also identified by its tracks, representing one of the first record known south of the Huancabamba Depression.

  15. Transport and Transformation of Dissolved Organic Matter in Soil Interstitial Water Across Forested, Montane Hillslopes

    Science.gov (United States)

    Burns, M. A.; McKnight, D. M.; Gabor, R. S.; Brooks, P. D.; Barnard, H. R.

    2013-12-01

    Dissolved organic matter (DOM) is a ubiquitous mixture of compounds formed from the degradation of both terrestrial and microbial material. The abundance and composition of the DOM present in stream water is important to stream processes such as UV light attenuation, nutrient supply and metal sorption. However, an excess of DOM can cause reactions with chlorination compounds at drinking water treatment plants, creating potentially harmful disinfection byproducts. Currently, little is known regarding the influence of soil interstitial water on stream DOM composition. In this study, we explore the role of interstitial water on DOM transport and transformation from the hillslope to the stream in a montane catchment within the Boulder Creek Critical Zone Observatory in Colorado. We installed a suite of tension lysimeters located within the rooting zone across representative north- and south-facing slopes. Interstitial water and stream samples were collected daily for approximately seven weeks during the 2013 spring snow melt period and analyzed for DOM composition using fluorescence spectroscopy. To date, we have used fluorescence index (FI) to evaluate differences between microbial and terrestrial DOM inputs and humification index (HIX) to assess degree of humification undergone by the DOM. Preliminary results indicate that FI was significantly correlated with hillslope aspect (pwater inputs into the stream during snowmelt. These preliminary results suggest that changes in DOM composition through the catchment during snowmelt can be linked to hydrologic transport. Further site specific model development will reveal explicit changes in the DOM chemistry and will increase our understanding of fundamental nutrient cycling processes at the hillslope to catchment scale.

  16. Green-tailed Towhee response to prescribed fire in montane shrubland

    Science.gov (United States)

    Jehle, G.; Savidge, J.A.; Kotliar, N.B.

    2006-01-01

    Fire alters the structure and composition of shrublands and affects habitat quality for the associated avifauna. Because shrubland ecosystems have been greatly reduced from their original extent in western North America and fire is increasingly being used to manage these landscapes, a better understanding of how fire affects the associated vegetation and wildlife is imperative. We evaluated the response of Green-tailed Towhees (Pipilo chlorurus) to prescribed fire in the montane shrublands of Rocky Mountain National Park, Colorado during 2002 and 2003. Three to five years following prescribed burning, Green-tailed Towhee density and shrub cover were generally higher in unburned areas. Nests (n = 179) were located in unburned vegetation; within burned sites, all nests were in remnant patches. Green-tailed Towhee nest survival was 57% (95% CI = 49%-65%) across the two years of the study. More than half of the nests were in common juniper (Juniperus communis) shrubs, and nest survival was higher for nests in junipers than those in other shrub species. Daily nest survival rates were lower at the site with the highest density of towhees and declined over the breeding season. With regard to shrub cover, opposite trends were observed for nest-site selection and nest survival: nest plots had greater shrub cover than non-nest plots, but nest survival decreased with increasing shrub cover. Because shrub cover affects towhee density and nest survival in conflicting ways, fire management at Rocky Mountain National Park alters both habitat availability and suitability for Green-tailed Towhees. ?? The Cooper Ornithological Society 2006.

  17. Patterns of mortality in a montane mixed-conifer forest in San Diego County, California.

    Science.gov (United States)

    Freeman, Mary Pyott; Stow, Douglas A; An, Li

    2017-07-17

    We examine spatial patterns of conifer tree mortality and their changes over time for the montane mixed-conifer forests of San Diego County. These forest areas have recently experienced extensive tree mortality due to multiple factors. A spatial contextual image processing approach was utilized with high spatial resolution digital airborne imagery to map dead trees for the years 1997, 2000, 2002, and 2005 for three study areas: Palomar, Volcan, and Laguna mountains. Plot-based fieldwork was conducted to further assess mortality patterns. Mean mortality remained static from 1997 to 2002 (4, 2.2, and 4.2 trees ha(-1) for Palomar, Volcan, and Laguna) and then increased by 2005 to 10.3, 9.7 and 5.2 trees ha(-1) , respectively. The increase in mortality between 2002 and 2005 represents the temporal pattern of a discrete disturbance event, attributable to the 2002-2003 drought. Dead trees are significantly clustered for all dates, based on spatial cluster analysis, indicating that they form distinct groups, as opposed to spatially random single dead trees. Other tests indicate no directional shift or spread of mortality over time, but rather an increase in density. While general temporal and spatial mortality processes are uniform across all study areas, the plot-based species and quantity distribution of mortality, and diameter distributions of dead versus living trees, vary by study area. The results of this study improve our understanding of stand- to landscape-level forest structure and dynamics, particularly by examining them from the multiple perspectives of field and remotely sensed data. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  18. Climate forcing of an emerging pathogenic fungus across a montane multi-host community

    Science.gov (United States)

    Clare, Frances C.; Halder, Julia B.; Daniel, Olivia; Bielby, Jon; Semenov, Mikhail A.; Jombart, Thibaut; Loyau, Adeline; Schmeller, Dirk S.; Cunningham, Andrew A.; Rowcliffe, Marcus; Bosch, Jaime

    2016-01-01

    Changes in the timings of seasonality as a result of anthropogenic climate change are predicted to occur over the coming decades. While this is expected to have widespread impacts on the dynamics of infectious disease through environmental forcing, empirical data are lacking. Here, we investigated whether seasonality, specifically the timing of spring ice-thaw, affected susceptibility to infection by the emerging pathogenic fungus Batrachochytrium dendrobatidis (Bd) across a montane community of amphibians that are suffering declines and extirpations as a consequence of this infection. We found a robust temporal association between the timing of the spring thaw and Bd infection in two host species, where we show that an early onset of spring forced high prevalences of infection. A third highly susceptible species (the midwife toad, Alytes obstetricans) maintained a high prevalence of infection independent of time of spring thaw. Our data show that perennially overwintering midwife toad larvae may act as a year-round reservoir of infection with variation in time of spring thaw determining the extent to which infection spills over into sympatric species. We used future temperature projections based on global climate models to demonstrate that the timing of spring thaw in this region will advance markedly by the 2050s, indicating that climate change will further force the severity of infection. Our findings on the effect of annual variability on multi-host infection dynamics show that the community-level impact of fungal infectious disease on biodiversity will need to be re-evaluated in the face of climate change. This article is part of the themed issue ‘Tackling emerging fungal threats to animal health, food security and ecosystem resilience’. PMID:28080980

  19. EFFICIENT FIR FILTER DESIGN METHODOLOGY USING DYNAMIC REGIONAL HARMONY SEARCH ALGORITHM WITH OPPOSITION AND LOCAL LEARNING (DRHS-OLL

    Directory of Open Access Journals (Sweden)

    P.Nirmala

    2014-08-01

    Full Text Available In this paper, an optimal design of FIR filter is carried out using a “Dynamic Regional Harmony Search algorithm (DRHS with Opposition and Local Learning”. The Harmony Search (HS is a robust optimization algorithm which mimics the musician’s improvisation method and has been used by many researchers for solving and optimizing various real-world optimization problems and numerical solutions. For optimizing the functionality of the FIR filter, DRHS algorithm which is an enhanced variant of the HS algorithm is adopted to avoid pre-mature convergence and stagnation. BY adopting DRHS algorithm the low pass, high pass, band pass and band stop FIR filters are constructed and their performances are evaluated and compared with the other existing optimization techniques. A comparison of the DRHS with other optimization algorithms for constructing FIR filter clearly shows the DRHS finds the optimal solution and the convergence is clearly guaranteed.

  20. Synchrotron FT-FIR spectroscopy of nitro-derivatives vapors: New spectroscopic signatures of explosive taggants and degradation products

    Science.gov (United States)

    Cuisset, Arnaud; Gruet, Sébastien; Pirali, Olivier; Chamaillé, Thierry; Mouret, Gaël

    2014-11-01

    We report on the first successful rovibrational study of gas phase mononitrotoluene and dinitrotoluene in the TeraHertz/Far-Infrared (THz/FIR) spectral domain. Using the AILES beamline of the synchrotron SOLEIL and a Fourier Transform spectrometer connected to multipass cells, the low-energy vibrational cross-sections of the different isomers of mononitrotoluene have been measured and compared to calculated spectra with the density functional theory including the anharmonic contribution. The active FIR modes of 2,4 and 2,6 dinitrotoluene have been assigned to the vibrational bands measured by Fourier Transform FIR spectroscopy of the gas-phase molecular cloud produced in an evaporating/recondensating system. This study highlights the selectivity of gas phase THz/FIR spectroscopy allowing an unambiguous recognition and discrimination of nitro-aromatic compounds used as explosive taggants.

  1. Wood quality and value production in mixed fir-spruce-beech stands: long-term research in the Western Carpathians

    Directory of Open Access Journals (Sweden)

    Petráš Rudolf

    2016-06-01

    Full Text Available Stem quality and damage was evaluated in mixed spruce-fir-beech stands. Moreover, an assortments structure was determined with their financial value. Results were compared with pure spruce (Picea abies [L.] Karst., fir (Abies alba Mill. and beech (Fagus sylvatica L. stands. Repeated measurements on 31 long-term research plots, stand assortment models, assortment yield models and value yield models were used. Stem quality of fir and spruce was only slightly lower in mixed stands compared to pure stands but beech stem quality was considerably worse in mixed stands. Fir and spruce had slightly lower proportions of better IIIA quality logs and higher proportions of IIIB quality in mixed stands. Beech had worse assortment structure than spruce and fir, in general. Pure beech stands had higher proportions of better I–IIIA quality assortments than mixed stands by 1–7%. Fir and spruce average value production (€ m−3 culminated at about 56 and 62 cm mean diameters. Almost the same value production was found in pure stands. In these stands it culminated at the mean diameter of 58 and 60 cm. Beech produced substantially less value on the same sites. In mixed stands, its value production culminated at the mean diameter of 40 cm. In pure stands, it culminated at the mean diameter of 36 cm. Although the production was found to be similar in both mixed and pure forests, higher damage intensity and less stem quality in mixed forests suggest that the pure forests can be more profitable.

  2. Gold and Displacement in Eastern Europe: Risks and Uncertainty at Roşia Montană

    Directory of Open Access Journals (Sweden)

    FILIP ALEXANDRESCU

    2011-01-01

    Full Text Available The Canadian-Romanian gold mining project at Roşia Montanǎ in Romania is known as the largest opencast gold mine being planned now in Europe. It involves the displacement of several thousand inhabitants, mostly former gold miners and a smaller number of farmers. The land and houses of more than three quarters of this population have already been acquired by the project owners, although the project has not yet received its formal environmental clearance. The paper analyzes the risks facing the displaced population of Roşia Montană, employing as analytical methodology the Impoverishment Risks and Reconstruction (IRR model, developed by Michael M. Cernea. The paper argues for an expansion of the IRR model. By taking into account the macro (extralocal forces that shape displacement and paying closer attention to the micro (subjective experience of this process, it becomes possible to understand the effects of uncertainty and vulnerability in displacement. The author's participant observations and in-depth interviews with local families are complemented with secondary analyses of data from several other socio-economic surveys and with the analysis of the Resettlement and Relocation Action Plan of the project owners.

  3. Deposition of mercury in forests across a montane elevation gradient: Elevational and seasonal patterns in methylmercury inputs and production

    Science.gov (United States)

    Gerson, Jacqueline R.; Driscoll, Charles T.; Demers, Jason D.; Sauer, Amy K.; Blackwell, Bradley D.; Montesdeoca, Mario R.; Shanley, James B.; Ross, Donald S.

    2017-08-01

    Global mercury contamination largely results from direct primary atmospheric and secondary legacy emissions, which can be deposited to ecosystems, converted to methylmercury, and bioaccumulated along food chains. We examined organic horizon soil samples collected across an elevational gradient on Whiteface Mountain in the Adirondack region of New York State, USA to determine spatial patterns in methylmercury concentrations across a forested montane landscape. We found that soil methylmercury concentrations were highest in the midelevation coniferous zone (0.39 ± 0.07 ng/g) compared to the higher elevation alpine zone (0.28 ± 0.04 ng/g) and particularly the lower elevation deciduous zone (0.17 ± 0.02 ng/g), while the percent of total mercury as methylmercury in soils decreased with elevation. We also found a seasonal pattern in soil methylmercury concentrations, with peak methylmercury values occurring in July. Given elevational patterns in temperature and bioavailable total mercury (derived from mineralization of soil organic matter), soil methylmercury concentrations appear to be driven by soil processing of ionic Hg, as opposed to atmospheric deposition of methylmercury. These methylmercury results are consistent with spatial patterns of mercury concentrations in songbird species observed from other studies, suggesting that future declines in mercury emissions could be important for reducing exposure of mercury to montane avian species.

  4. Rapid upslope shifts in New Guinean birds illustrate strong distributional responses of tropical montane species to global warming.

    Science.gov (United States)

    Freeman, Benjamin G; Class Freeman, Alexandra M

    2014-03-25

    Temperate-zone species have responded to warming temperatures by shifting their distributions poleward and upslope. Thermal tolerance data suggests that tropical species may respond to warming temperatures even more strongly than temperate-zone species, but this prediction has yet to be tested. We addressed this data gap by conducting resurveys to measure distributional responses to temperature increases in the elevational limits of the avifaunas of two geographically and faunally independent New Guinean mountains, Mt. Karimui and Karkar Island, 47 and 44 y after they were originally surveyed. Although species richness is roughly five times greater on mainland Mt. Karimui than oceanic Karkar Island, distributional shifts at both sites were similar: upslope shifts averaged 113 m (Mt. Karimui) and 152 m (Karkar Island) for upper limits and 95 m (Mt. Karimui) and 123 m (Karkar Island) for lower limits. We incorporated these results into a metaanalysis to compare distributional responses of tropical species with those of temperate-zone species, finding that average upslope shifts in tropical montane species match local temperature increases significantly more closely than in temperate-zone montane species. That tropical species appear to be strong responders has global conservation implications and provides empirical support to hitherto untested models that predict widespread extinctions in upper-elevation tropical endemics with small ranges.

  5. Ranging behavior of eastern hoolock gibbon (Hoolock leuconedys) in a northern montane forest in Gaoligongshan, Yunnan, China.

    Science.gov (United States)

    Zhang, Dao; Fei, Han-Lan; Yuan, Sheng-Dong; Sun, Wen-Mo; Ni, Qing-Yong; Cui, Liang-Wei; Fan, Peng-Fei

    2014-04-01

    Generally, food abundance and distribution exert important influence on primate ranging behavior. Hoolock gibbons (genus Hoolock) live in lowland and montane forests in India, Bangladesh, Myanmar and China. All information about hoolock gibbons comes from studies on western hoolock gibbons (Hoolock hoolock) living in lowland forest. Between August 2010 and September 2011, we studied the ranging behavior of one habituated group of eastern hoolock gibbon (H. leuconedys) living in a seasonal montane forest in Gaoligongshan, Yunnan, China. Results show that the study group did not increase foraging effort, calculated in this study as the daily path length, when fruit was less available. Instead, the gibbons fed more on leaves and decreased traveling to conserve energy. They relied heavily on a single food species in most study months which was patchily distributed within their total (14-month) home range, and during most months they used only a small portion of their total home range. In order to find enough food, the group shifted its monthly home range according to the seasonal availability of food species. To satisfy their annual food requirements, they occupied a total home range of 93 ha. The absence of neighboring groups of gibbons and the presence of tsaoko cardamom (Amomum tsaoko) plantations may also have influenced the ranging behavior of the group. Further long-term studies of neighboring groups living in intact forests are required to assess these effects.

  6. Response of epiphytic bryophytes to simulated N deposition in a subtropical montane cloud forest in southwestern China.

    Science.gov (United States)

    Song, Liang; Liu, Wen-Yao; Ma, Wen-Zhang; Qi, Jin-Hua

    2012-11-01

    A field manipulation experiment was conducted in a subtropical montane cloud forest in southwestern China to determine the possible responses of epiphytic bryophytes to increasing nitrogen (N) deposition from community to physiology level, and to find sensitive epiphytic bryophytes that may be used as indicators for assessing the degree of N pollution. N addition had significantly negative effects on species richness and cover of the epiphytic bryophyte community. Harmful effects of high N loads were recorded for chlorophyll, growth, and vitality of the species tested. The decline of some epiphytic bryophytes may result from detrimental effects on degradation to photosynthetic pigments. Bazzania himalayana (Mitt.) Schiffn., Bazzania ovistipula (Steph.) Mizut., and Homaliodendron flabellatum (Sm.) Fleisch. are candidates in atmospheric nitrogen monitoring. Epiphytic bryophytes in the montane cloud forest are very sensitive to increasing N deposition and often difficult to recover once they have been destroyed, providing early detection of enhanced N pollution for trees or even the whole forest ecosystem. The inference that increasing N pollution may lead to loss of biodiversity is a concern to the developing economy in western China, and should alert the government to the adverse impacts caused by increased industrial pollution during the process of China's West Development.

  7. THERMO-VACUUM MODIFICATION OF SPRUCE (PICEA ABIES KARST. AND FIR (ABIES ALBA MILL. WOOD

    Directory of Open Access Journals (Sweden)

    Ottaviano Allegretti,

    2012-06-01

    Full Text Available The study presents results of the characterization of Norway spruce (Picea abies Karst. and fir (Abies alba Mill. wood thermally modified by TERMOVUOTO® technology at temperatures in the range of 160 to 220°C in vacuum conditions. Sixteen thermo-vacuum treatment tests were carried out using a pilot laboratory unit on 30-mm-thick spruce and fir boards in various combinations of the process parameters, i.e. temperature (T, duration (t, and pressure (p. The treated material was characterized to reveal the changes of the physical-mechanical properties including color and durability. The treated wood showed an improved performance with relation to the dimensional stability and durability. The measured mechanical properties did not show any significant decrease. Analytical models, based on the existing correlations between wood properties and process parameters, were assessed, thus allowing the control of the process.

  8. The protostar OMC-2 FIR 4: Results from the CHESS Herschel/HIFI spectral survey

    Science.gov (United States)

    Kama, Mihkel; Lopez-Sepulcre, Ana; Ceccarelli, Cecilia; Dominik, Carsten; Caux, Emmanuel; Fuente, Asuncion

    2013-07-01

    The intermediate-mass protostar OMC-2 FIR 4 in Orion is the focus of several ongoing studies, including a CHESS key programme Herschel/HIFI spectral survey. In this poster, we review recent CHESS results on this source, including the properties of the central hot core, the presence of a compact outflow, the spatial variation of the chemical composition, and the discovery of a tenuous foreground cloud. The HIFI spectrum of FIR 4 contains 719 lines from 40 species and isotopologs. Cooling by lines detectable with our sensitivity contributes 2% of the total in the 480 to 1900 GHz range. The total line flux is dominated by CO, followed by H2O and CH3OH. Initial comparisons with spectral surveys of other sources will also be presented.

  9. Generic Feasibility of Perfect Reconstruction with Short FIR Filters in Multi-channel Systems

    CERN Document Server

    Sharif, Behzad

    2011-01-01

    We study the feasibility of short finite impulse response (FIR) synthesis for perfect reconstruction (PR) in generic FIR filter banks. Among all PR synthesis banks, we focus on the one with the minimum filter length. For filter banks with oversampling factors of at least two, we provide prescriptions for the shortest filter length of the synthesis bank that would guarantee PR almost surely. The prescribed length is as short or shorter than the analysis filters and has an approximate inverse relationship with the oversampling factor. Our results are in form of necessary and sufficient statements that hold generically, hence only fail for elaborately-designed nongeneric examples. We provide extensive numerical verification of the theoretical results and demonstrate that the gap between the derived filter length prescriptions and the true minimum is small. The results have potential applications in synthesis FB design problems, where the analysis bank is given, and for analysis of fundamental limitations in blin...

  10. Pathology of a Gammabaculovirus in Its Natural Balsam Fir Sawfly (Neodiprion abietis Host

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    Christopher J. Lucarotti

    2012-01-01

    Full Text Available The Neodiprion abietis Gammabaculovirus (Baculoviridae: NeabNPV is virulent, highly contagious, and infects only midgut epithelial cells of balsam fir sawfly larvae, but infections can carry through to adult sawflies in the midgut. Larval infections are characterized by hypertrophy of midgut epithelial cell nuclei, where virogenic stromata develop to produce nucleocapsids that are singly enveloped before occlusion into occlusion bodies. Infected, occlusion body-laden cells slough from the midgut epithelium as a result of a dissolution of the basal lamina. Infected cells undergo lysis, and viral occlusion bodies exit affected larvae in a watery diarrhea to infect other balsam fir sawfly larvae. A budded virus stage was not observed, but nucleocapsid and occlusion body formation resembled the development of occlusion-derived virions and occlusion bodies in lepidopteran alphabaculoviruses.

  11. Sharpening the response of an FIR filter using Fractional Fourier Transform

    Directory of Open Access Journals (Sweden)

    Somesh Chaturvedi

    2012-03-01

    Full Text Available In this paper we have implemented FIR filter with the help of Kaiser Window and Fractional Fourier Transform (FRFT. The window shape parameter is tuned for the transition band by considering linear phase FRFT Finite Impulse Response (FIR filter. Here FRFT of Kaiser Window is taken and convolved with the response function for tuning purposes of the transition band which makes effective transition band. This proposed method includes the change of parameters of Kaiser window by which other windows like Rectangle, Bartlett, Hamming Blackman and Hanning windows are generated by using FRFT. The efficiencies of this method in terms of main lobe and side ripples are better than the above mentioned windows under Fourier transform.

  12. EuroFIR eBASIS: application for health claims submissions and evaluations

    DEFF Research Database (Denmark)

    Kiely, M.; Black, L.J.; Plumb, J.;

    2010-01-01

    Background: The European Food Information Resource (EuroFIR) network has established the eBASIS (Bioactive Substances in Food Information System) online food composition and biological effects database for plant-derived bioactive compounds (phytochemicals). On the basis of submitted evidence......BASIS. Of the 222 defined article 14 claims, 21 pertain to plants or plant-based bioactive compounds, of which 19 are in eBASIS. Conclusions: There is extensive overlap between eBASIS and the submitted health claims that relate to plant-based bioactive compounds. EuroFIR eBASIS is a useful tool for regulators...... to independently check completeness of health claims applications relating to phytochemicals and is a potentially valuable resource to assist claimants in the compilation of dossiers on functional foods and health claims. European Journal of Clinical Nutrition (2010) 64, S101-S107; doi:10.1038/ejcn.2010.219...

  13. Increased water deficit decreases Douglas fir growth throughout western US forests

    Science.gov (United States)

    Restaino, Christina M; Peterson, David L.; Littell, Jeremy

    2016-01-01

    Changes in tree growth rates can affect tree mortality and forest feedbacks to the global carbon cycle. As air temperature increases, evaporative demand also increases, increasing effective drought in forest ecosystems. Using a spatially comprehensive network of Douglas-fir (Pseudotsuga menziesii) chronologies from 122 locations that experience distinctly different climate in the western United States, we show that increased temperature decreases growth via vapor pressure deficit (VPD) across all latitudes. Under an ensemble of global circulation models, we project an increase in both the mean VPD associated with the lowest growth extremes and the probability of exceeding these VPD values. As temperature continues to increase in future decades, we can expect deficit-related stress to increase and consequently Douglas-fir growth to decrease throughout its US range.

  14. Comparisons of FIR and IIR implementations of a subtraction-based stimulus artifact rejection algorithm.

    Science.gov (United States)

    Azin, Meysam; Chiel, Hillel J; Mohseni, Pedram

    2007-01-01

    Finite impulse response (FIR) and infinite impulse response (IIR) temporal filtering techniques are investigated to assess the feasibility of very-large-scale-integrated (VLSI) implementation of a subtraction-based stimulus artifact rejection (SAR) algorithm in implantable, closed-loop neuroprostheses. The two approaches are compared in terms of their system architectures, overall performances, and the associated computational costs. Pre-recorded neural data from an Aplysia californica are used to demonstrate the functionality of the proposed implementations. Digital building blocks for an FIR-based system are also simulated in a 0.18-microm CMOS technology, showing a total power consumption of IIR-based system can further reduce the required power consumption and die area.

  15. Increased water deficit decreases Douglas fir growth throughout western US forests.

    Science.gov (United States)

    Restaino, Christina M; Peterson, David L; Littell, Jeremy

    2016-08-23

    Changes in tree growth rates can affect tree mortality and forest feedbacks to the global carbon cycle. As air temperature increases, evaporative demand also increases, increasing effective drought in forest ecosystems. Using a spatially comprehensive network of Douglas fir (Pseudotsuga menziesii) chronologies from 122 locations that represent distinct climate environments in the western United States, we show that increased temperature decreases growth via vapor pressure deficit (VPD) across all latitudes. Using an ensemble of global circulation models, we project an increase in both the mean VPD associated with the lowest growth extremes and the probability of exceeding these VPD values. As temperature continues to increase in future decades, we can expect deficit-related stress to increase and consequently Douglas fir growth to decrease throughout its US range.

  16. Increased Biomass of Nursery-Grown Douglas-Fir Seedlings upon Inoculation with Diazotrophic Endophytic Consortia

    Directory of Open Access Journals (Sweden)

    Zareen Khan

    2015-10-01

    Full Text Available Douglas-fir (Pseudotsuga menziesii seedlings are periodically challenged by biotic and abiotic stresses. The ability of endophytes to colonize the interior of plants could confer benefits to host plants that may play an important role in plant adaptation to environmental changes. In this greenhouse study, nursery-grown Douglas-fir seedlings were inoculated with diazotrophic endophytes previously isolated from poplar and willow trees and grown for fifteen months in nutrient-poor conditions. Inoculated seedlings had significant increases in biomass (48%, root length (13% and shoot height (16% compared to the control seedlings. Characterization of these endophytes for symbiotic traits in addition to nitrogen fixation revealed that they can also solubilize phosphate and produce siderophores. Colonization was observed through fluorescent microscopy in seedlings inoculated with gfp- and mkate-tagged strains. Inoculation with beneficial endophytes could prove to be valuable for increasing the production of planting stocks in forest nurseries.

  17. Non-Causal Fir Filters for the Maximum Return from Capital Markets

    CERN Document Server

    Dyka, A

    2006-01-01

    In this paper we consider a trading strategy, which consists in buying or selling a financial instrument when the smoothing, non-causal FIR (Final Impulse Response) filter output attains a local minimum or maximum, respectively. Upon tis assumption the goal of this paper is to determine the 'best' non-causal smoothing FIR filters, which provide maximum value of the return from the market. The assumed non-causality is obtained by advancing the output signal to compensate for the delay introduced by the a priori known filter. The best result were obtained for the impulse response given by the Pascal triangle and the family of symmetric power triangles, both for the case of trading with, and without the transaction fee. It was found that the transaction fee dramatically reduces a possible net return from the market, and therefore should not be omitted in market analyzes.

  18. EFFECT OF STEAM-HEAT TREATMENT ON MECHANICAL PROPERTIES OF CHINESE FIR

    Directory of Open Access Journals (Sweden)

    Yongjian Cao

    2012-01-01

    Full Text Available Heat treatment often brings about some negative effects on mechanical properties of wood. Chinese fir is currently underutilized due to some inherent properties that limit its further applications. Using steam as a heating medium and a shielding gas, the heartwood and sapwood of Chinese fir were treated at a temperature ranging from 170ºC to 230ºC and time from 1 to 5 hours in an airtight chamber. Both the modulus of rupture (MOR and modulus of elasticity (MOE were increased for the sapwood specimens under the temperature less than 200ºC for short treatment times. The hardness was increased for both two kinds of specimens under the temperature less than or about 200ºC, compared to the untreated specimens. The temperature has a stronger effect on mechanical properties of wood than the time, and the temperature of 200 ºC is a critical point in modifying mechanical properties of wood.

  19. Soil-mediated effects of atmospheric deposition on eastern US spruce-fir forests. Book chapter

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, D.W.; Fernandez, I.J.

    1992-01-01

    The coincident observation of Waldsterben in Germany and red spruce decline in the northeastern U.S. has naturally led to some speculation that similar mechanisms may be involved. In the German situation, soil-mediated hypotheses played (and still play) a major role; namely, soil acidification and aluminum toxicity and base cation deficiencies. In the red spruce case, there has been much concern that cation deficiencies and/or aluminum toxicity may also play a major role. The purpose of this chapter is to: (1) review some of the basic properties of soils, nutrition, and nutrient cycling in spruce-fir and fir ecosystems, both in the polluted and in the relatively unpolluted regions of the U.S. and Canada, and (2) to evaluate several soil acidity-related hypotheses for red spruce decline.

  20. Design of Hilbert transformers with tunable THz bandwidths using a reconfigurable integrated optical FIR filter

    Science.gov (United States)

    Ngo, Nam Quoc; Song, Yufeng; Lin, Bo

    2011-02-01

    We present the design and analysis of a wideband and tunable optical Hilbert transformer (OHT) using a tunable waveguide-based finite-impulse response (FIR) filter structure by using the digital filter design method and the Remez algorithm. The tunable Nth-order waveguide-based FIR filter, which simply consists of N delay lines, N tunable couplers, N tunable phase shifters and a combiner, can be tuned, by thermally adjusting the tunable couplers and tunable phase shifters, to tune the bandwidth of an OHT using silica-based planar lightwave circuit (PLC) technology. To demonstrate the effectiveness of the method, the simulation results have an excellent agreement with the theoretical predictions. The tunable OHT can function as a wideband and tunable 90° phase shifter and thus has many potential applications. The two unique features of wideband characteristic (up to ~ 2 THz) and tunable bandwidth (THz tuning range) of the proposed OHT cannot be obtained from the existing OHTs.

  1. Aspirated pits in wetwood and micromorphology of microbial degradation in subalpine fir

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yaoli; CAI Liping; XU Yongji

    2006-01-01

    Differentiating from normal wood,pit membranes in wetwood of subalpine fir contain bacteria of water drop shape or orbicular shape,and flaky shape,as observed using Scanning Electronic Microscope.Not only are ray parenchyma cells in wetwood partially degraded but also margo strands in pit membranes are somewhat degraded by bacterial activities.Most of the bordered-pit membranes in normal wood are unaspirated in green conditions and the proportions of aspirated pits in earlywood and latewood account for only 6.8% and 13.4%,respectively.Nevertheless,most of the bordered-pit membranes in wetwood are aspirated in green conditions and the proportions of aspirated pits account for 77.7% and 72.1%,respectively.The problem of hard-to-dry for subalpine fir could be reasoned from the considerable amount of aspirated pit membranes in wetwood.

  2. HR approximation of FIR filters via discrete-time hybrid-domain vector fitting

    OpenAIRE

    2009-01-01

    We present a discrete-time hybrid-domain vector fitting algorithm, called HD-VFz, for the HR approximation of FIR filters with an arbitrary combination of time- and frequency-sampled responses. The core routine involves a two-step pole refinement process based on a linear least-squares solve and an eigenvalue problem. Through hybrid-domain data approximation and digital partial fraction basis with relative stability consideration, HD-VFz exhibits fast computation and remarkable fitting accura...

  3. Fire, fuels, and restoration of ponderosa pine-Douglas-fir forests in the Rocky Mountains

    OpenAIRE

    Baker, W. L.; T. T. Veblen; Sherriff, R. L.

    2007-01-01

    Forest restoration in ponderosa pine and mixed ponderosa pine–Douglas fir forests in the US Rocky Mountains has been highly influenced by a historical model of frequent, low-severity surface fires developed for the ponderosa pine forests of the Southwestern USA. A restoration model, based on this low-severity fire model, focuses on thinning and prescribed burning to restore historical forest structure. However, in the US Rocky Mountains, research on fire history and forest structure, and earl...

  4. Ecological adaptations in Douglas-fir (Psuedotsuga menziesii var. glauca): a synthesis

    Science.gov (United States)

    Gerald Rehfeldt

    1989-01-01

    Measurements of 3rd-year height of 228 seedling populations, grown in four separate studies in two of the same common gardens, were used to summarize patterns of genetic variation for Douglas-fir across 250 000 km 2 of forested lands in Idaho and Montana, U.S.A. Because each study was conducted in different years with a different set of populations, measurements were...

  5. On the Nature of the Deeply Embedded Protostar OMC-2 FIR 4

    Science.gov (United States)

    Furlan, E.; Megeath, S. T.; Osorio, M.; Stutz, A. M.; Fischer, W. J.; Ali, B.; Stanke, T.; Manoj, P.; Adams, J. D.; Tobin, J. J.

    2014-05-01

    We use mid-infrared to submillimeter data from the Spitzer, Herschel, and Atacama Pathfinder Experiment telescopes to study the bright submillimeter source OMC-2 FIR 4. We find a point source at 8, 24, and 70 μm, and a compact, but extended source at 160, 350, and 870 μm. The peak of the emission from 8 to 70 μm, attributed to the protostar associated with FIR 4, is displaced relative to the peak of the extended emission; the latter represents the large molecular core the protostar is embedded within. We determine that the protostar has a bolometric luminosity of 37 L ⊙, although including more extended emission surrounding the point source raises this value to 86 L ⊙. Radiative transfer models of the protostellar system fit the observed spectral energy distribution well and yield a total luminosity of most likely less than 100 L ⊙. Our models suggest that the bolometric luminosity of the protostar could be as low as 12-14 L ⊙, while the luminosity of the colder (~20 K) extended core could be around 100 L ⊙, with a mass of about 27 M ⊙. Our derived luminosities for the protostar OMC-2 FIR 4 are in direct contradiction with previous claims of a total luminosity of 1000 L ⊙. Furthermore, we find evidence from far-infrared molecular spectra and 3.6 cm emission that FIR 4 drives an outflow. The final stellar mass the protostar will ultimately achieve is uncertain due to its association with the large reservoir of mass found in the cold core.

  6. Phylogeography of SW Mediterranean firs: different European origins for the North African Abies species.

    Science.gov (United States)

    Sánchez-Robles, Jose M; Balao, Francisco; Terrab, Anass; García-Castaño, Juan L; Ortiz, María A; Vela, Errol; Talavera, Salvador

    2014-10-01

    The current distribution of Western Mediterranean Abies species is a result of complex geodynamic processes and climatic oscillations that occurred in the past. Abies sect. Piceaster offers a good study model to explore how geo-climatic oscillations might have influenced its expansion and diversification on both sides of the W Mediterranean basin. We investigated the genetic variation within and among nine populations from five Abies species by molecular markers with high and low mutation rates and contrasting inheritance (AFLP and cpSSR). Analyses revealed the opening of the Strait of Gibraltar as an effective barrier against gene flow between the Southern Iberian (A. pinsapo) and North African (A. marocana and A. tazaotana) firs. The A. pinsapo populations in Spain and likewise those of the A. marocana - A. tazaotana population complex were not differentiated, and no evidence was found to distinguish A. tazaotana at the species level. Diversification of Abies across North Africa could occur by way of at least two vicariant events from Europe, in the west, giving rise to the A. marocana - A. tazaotana complex, and in the east, giving A. numidica. Secondary contacts among species from Abies sect. Piceaster (A. pinsapo and A. numidica), and with A. alba (Abies sect. Abies) are also indicated. However, there is a closer relationship between the Algerian fir (A. numidica) and the North Mediterranean widespread A. alba, than with the Moroccan firs (A. marocana and A. tazaotana) or the Southern Iberian (A. pinsapo). We also discuss the distribution range of these taxa in its paleogeological and paleoclimatic context, and propose that part of the modern geography of the South-Western Mediterranean firs might be traced back to the Tertiary.

  7. Belowground biomass and nutrient content in a 47-year-old Douglas-fir plantation

    OpenAIRE

    J. Ranger; Gelhaye, D.

    2001-01-01

    International audience; Biomass and nutrient content of the root system of a Douglas-fir stand were calculated using the regression technique. Nine trees, evenly distributed in the girth classes of the stand, were felled for measurements and sampling. Results were compared to published data. Statistically significant relationships between tree circumference at 1.30 m and root biomass or nutrient content were observed. The root biomass was 58 t of dry matter, which was 18% of the total stand b...

  8. Ability of natural extracts to limit mold growth on Douglas-fir sapwood

    OpenAIRE

    Michal Maoz; Joseph J. Karchesy; Jeffrey J. Morrell

    2012-01-01

    The ability of selected plant extracts from wood and foliage to inhibit mold regrowth on fungal colonized wood was evaluated on Douglas-fir sapwood. Most foliage extracts produced some inhibition of Graphium or Trichoderma species, but isolations of other fungi increased following treatment. Five out of eight wood extracts produced 50% reductions in isolations, and those from Alaska cedar, western juniper, and incense cedar produced at least 80% reductions. The results indicate that wood ext...

  9. On the nature of the deeply embedded protostar OMC-2 FIR 4

    Energy Technology Data Exchange (ETDEWEB)

    Furlan, E. [National Optical Astronomy Observatory, 950 N. Cherry Avenue, Tucson, AZ 85719 (United States); Megeath, S. T.; Fischer, W. J. [Ritter Astrophysical Observatory, Department of Physics and Astronomy, University of Toledo, 2801 W. Bancroft Street, Toledo, OH 43606 (United States); Osorio, M. [Instituto de Astrofísica de Andalucía, CSIC, Camino Bajo de Huétor 50, E-18008 Granada (Spain); Stutz, A. M. [Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany); Ali, B. [NHSC/IPAC, California Institute of Technology, 770 S. Wilson Ave., Pasadena, CA 91125 (United States); Stanke, T. [ESO, Karl-Schwarzschild-Strasse 2, D-85748, Garching bei München (Germany); Manoj, P. [Department of Astronomy and Astrophysics, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005 (India); Adams, J. D. [USRA-SOFIA, DAOF, 2825 E. Ave. P, Palmdale, CA 93550 (United States); Tobin, J. J., E-mail: furlan@ipac.caltech.edu [National Radio Astronomy Observatory, Charlotttesville, VA 22903 (United States)

    2014-05-01

    We use mid-infrared to submillimeter data from the Spitzer, Herschel, and Atacama Pathfinder Experiment telescopes to study the bright submillimeter source OMC-2 FIR 4. We find a point source at 8, 24, and 70 μm, and a compact, but extended source at 160, 350, and 870 μm. The peak of the emission from 8 to 70 μm, attributed to the protostar associated with FIR 4, is displaced relative to the peak of the extended emission; the latter represents the large molecular core the protostar is embedded within. We determine that the protostar has a bolometric luminosity of 37 L {sub ☉}, although including more extended emission surrounding the point source raises this value to 86 L {sub ☉}. Radiative transfer models of the protostellar system fit the observed spectral energy distribution well and yield a total luminosity of most likely less than 100 L {sub ☉}. Our models suggest that the bolometric luminosity of the protostar could be as low as 12-14 L {sub ☉}, while the luminosity of the colder (∼20 K) extended core could be around 100 L {sub ☉}, with a mass of about 27 M {sub ☉}. Our derived luminosities for the protostar OMC-2 FIR 4 are in direct contradiction with previous claims of a total luminosity of 1000 L {sub ☉}. Furthermore, we find evidence from far-infrared molecular spectra and 3.6 cm emission that FIR 4 drives an outflow. The final stellar mass the protostar will ultimately achieve is uncertain due to its association with the large reservoir of mass found in the cold core.

  10. Design and Efficiency Analysis of one Class of Uniform Linear Phase FIR Filter Banks

    Directory of Open Access Journals (Sweden)

    R. D. Pantić

    2013-11-01

    Full Text Available One class of uniform linear phase filter banks with different numbers of band-pass channels will be considered in this study, concentrating on 5, 9 and 17-band filter banks and their mutual comparison concerning delay and implementation complexity. Designed banks are based on the FIR filters and frequency response masking technique and are also compared to the banks with direct realization considering complementarity and delay.

  11. A tool for automatic generation of RTL-level VHDL description of RNS FIR filters

    DEFF Research Database (Denmark)

    Re, Andrea Del; Nannarelli, Alberto; Re, Marco

    2004-01-01

    Although digital filters based on the Residue Number System (RNS) show high performance and low power dissipation, RNS filters are not widely used in DSP systems, because of the complexity of the algorithms involved. We present a tool to design RNS FIR filters which hides the RNS algorithms to th...... to the designer, and generates a synthesizable VHDL description of the filter taking into account several design constraints such as: delay, area and energy....

  12. Acidification Sources in Red Alder and Douglas-Fir Soils -- Importance of Nitrification

    OpenAIRE

    Miegroet, Helga Van; Cole, D. W.

    1985-01-01

    Precipitation, throughfall, forest floor, and soil leachate samples were monitored continuously in 1981 and 1982 in a N-poor Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] forest and a red alder (Alnus rubra Bong.) forest growing adjacently on a glacial soil in western Washington. The purpose of the study was to quantify the relative importance of atmospheric vs. natural sources of H+ input to forest soil acidification, and to determine the role of N transformation processes in the overa...

  13. Seasonal dynamics of phloem formation in Silver fir and Norway spruce as affected by drought

    OpenAIRE

    Gričar, Jožica; Čufar, Katarina

    2015-01-01

    The dynamics of phloem growth ring formation in silver fir (Abies alba Mill.) and Norway spruce (Picea abies Karst.) at different sites in Slovenia during the droughty growing season of 2003 was studied. We also determined the timing of cambial activity, xylem and phloem formation, and counted the number of cells in the completed phloem and xylem growth rings. Light microscopy of cross-sections revealed that cambial activity started on the phloem and xylem side simultaneously at all 3 plots. ...

  14. Climate Change, Wildfires and Fir Forests in Greece: Perceptions of Forest Managers

    OpenAIRE

    Ioannis Mitsopoulos; Yannis Raftoyannis; Dimitrios Bakaloudis

    2015-01-01

    Background and Purpose: The potential impact that climate change may have on fire regime in ecosystems that are not fire-dependent emerges from fires that are nowadays spreading over higher altitudes and northern latitudes. The effects of fire occurrence in high elevation forests of Greece became apparent during the last few years when a number of large forest fires burned a significant number of high altitude fir ecosystems. This paper describes a study that investigated perceptions of wildf...

  15. Influence of prevailing disturbances on soil biology and biochemistry of montane habitats at Nanda Devi Biosphere Reserve, India during wet and dry seasons

    DEFF Research Database (Denmark)

    Singh, S.K.; Singh, Anoop; Rai, J.P.N.

    2011-01-01

    The impact of prevailing disturbances in montane habitats of Nanda Devi Biosphere Reserve (NDBR) was studied on soil microbial population, biomass, soil respiration and enzyme activities during wet and dry seasons. The physico-chemical characteristics of soils exhibited conspicuous variation in t...

  16. Flea abundance, diversity, and plague in Gunnison's prairie dogs (Cynomys gunnisoni) and their burrows in montane grasslands in northern New Mexico

    Science.gov (United States)

    Megan M. Friggens; Robert R. Parmenter; Michael Boyden; Paulette L. Ford; Kenneth Gage; Paul Keim

    2010-01-01

    Plague, a flea-transmitted infectious disease caused by the bacterium Yersinia pestis, is a primary threat to the persistence of prairie dog populations (Cynomys spp.). We conducted a 3-yr survey (2004-2006) of fleas from Gunnison's prairie dogs (Cynomys gunnisoni) and their burrows in montane grasslands in Valles Caldera National Preserve in New Mexico. Our...

  17. Time-Varying FIR Equalization for MIMO Transmission over Doubly Selective Channels

    Directory of Open Access Journals (Sweden)

    Marc Moonen

    2010-01-01

    Full Text Available We propose time-varying FIR equalization techniques for spatial multiplexing-based multiple-input multiple-output (MIMO transmission over doubly selective channels. The doubly selective channel is approximated using the basis expansion model (BEM, and equalized by means of time-varying FIR filters designed according to the BEM. By doing so, the time-varying deconvolution problem is converted into a two-dimensional time-invariant deconvolution problem in the time-invariant coefficients of the channel BEM and the time-invariant coefficients of the equalizer BEM. The timevarying FIR equalizers are derived based on either the matched filtering criterion, or the linear minimum mean-square error (MMSE or the zero-forcing (ZF criteria. In addition to the linear equalizers, the decision feedback equalizer (DFE is proposed. The DFE can be designed according to two different scenarios. In the first scenario, the DFE is based on feeding back previously estimated symbols from one particular antenna at a time. Whereas, in the second scenario, the previously estimated symbols from all transmit antennas are fed back together. The performance of the proposed equalizers in the context of MIMO transmission is analyzed in terms of numerical simulations.

  18. High angular resolution observations towards OMC-2 FIR 4: Dissecting an intermediate-mass protocluster

    CERN Document Server

    López-Sepulcre, A; Sánchez-Monge, Á; Ceccarelli, C; Dominik, C; Kama, M; Caux, E; Fontani, F; Fuente, A; Ho, P T P; Neri, R; Shimajiri, Y

    2013-01-01

    OMC-2 FIR 4 is one of the closest known young intermediate-mass protoclusters, located at a distance of 420 pc in Orion. This region is one of the few where the complete 500-2000 GHz spectrum has been observed with the heterodyne spectrometer HIFI on board the Herschel satellite, and unbiased spectral surveys at 0.8, 1, 2 and 3 mm have been obtained with the JCMT and IRAM 30-m telescopes. In order to investigate the morphology of this region, we used the IRAM Plateau de Bure Interferometer to image OMC-2 FIR 4 in the 2-mm continuum emission, as well as in DCO+(2-1), DCN(2-1), C34S(3-2), and several CH3OH lines. In addition, we analysed observations of the NH3(1,1) and (2,2) inversion transitions made with the Very Large Array of the NRAO. The resulting maps have an angular resolution which allows us to resolve structures of 5", equivalent to 2000 AU. Our observations reveal three spatially resolved sources within OMC-2 FIR 4, of one or several solar masses each, with hints of further unresolved substructure w...

  19. FIR Spectroscopy of the Galactic Center: Hot and Warm Molecular Gas

    Science.gov (United States)

    Goicoechea, Javier R.; Etxaluze, Mireya; Cernicharo, José; Gerin, Maryvonne; Pety, Jerome

    2017-01-01

    The angular resolution (~10'') achieved by the Herschel Space Observatory ~3.5 m telescope at FIR wavelengths allowed us to roughly separate the emission toward the inner parsec of the galaxy (the central cavity) from that of the surrounding circumnuclear disk (the CND). The FIR spectrum toward Sgr A* is dominated by intense [O III], [O I], [C II], [N III], [N II], and [C I] fine-structure lines (in decreasing order of luminosity) arising in gas irradiated by the strong UV field from the central stellar cluster. The high-J CO rotational line intensities observed at the interface between the inner CND and the central cavity are consistent with a hot isothermal component at T k ~ 103.1 K and n(H2)~ 104 cm-3. They are also consistent with a distribution of lower temperatures at higher gas density, with most CO at T k~300 K. The hot CO component (either the bulk of the CO column density or just a small fraction depending on the above scenario) likely results from a combination of UV and shock-driven heating. If UV-irradiated and heated dense clumps do not exist, shocks likely dominate the heating of the hot molecular gas component. Although this component is beam diluted in our FIR observations, it may be resolved at much higher angular resolution. An ALMA project using different molecular tracers to characterize UV-irradiated shocks in the innermost layers of the CND is ongoing.

  20. Performance of swarm based optimization techniques for designing digital FIR filter: A comparative study

    Directory of Open Access Journals (Sweden)

    I. Sharma

    2016-09-01

    Full Text Available In this paper, a linear phase FIR filter is designed through recently proposed nature inspired optimization algorithm known as Cuckoo search (CS. A comparative study of Cuckoo search (CS, particle swarm optimization (PSO and artificial bee colony (ABC nature inspired optimization methods in the field of linear phase FIR filter design is also presented. For this purpose, an improved L1 weighted error function is formulated in frequency domain, and minimized through CS, PSO and ABC respectively. The error or objective function has a controlling parameter wt which controls the amount of ripple in the desired band of frequency. The performance of FIR filter is examined through three key parameters; Maximum Pass Band Ripple (MPR, Maximum Stopband Ripple (MSR and Stopband Attenuation (As. Comparative study and the simulation results reveal that the designed filter with CS gives better performance in terms of Maximum Stopband Ripple (MSR, and Stopband Attenuation (As for low order filter design, and for higher order it also gives better performance in term of Maximum Passband Ripple (MPR. Superiority of the proposed technique is also shown through comparison with other recently proposed methods.

  1. An advanced strategy for wind speed forecasting using expert 2-D FIR filters

    Directory of Open Access Journals (Sweden)

    MOGHADDAM, A. A.

    2010-11-01

    Full Text Available Renewable energies such as wind and solar have become the most attractive means of electricity generation nowadays. Social and environmental benefits as well as economical issues result in further utilization of such these energy resources. In this regard, wind energy plays an important roll in operation of small-scale power systems like Micro Grid. On the other hand, wind stochastic nature in different time and place horizons, makes accurate forecasting of its behavior an inevitable task for market planners and energy management systems. In this paper an advanced strategy for wind speed estimation has been purposed and its superior performance is compared to that of conventional methods. The model is based on linear predictive filtering and image processing principles using 2-D FIR filters. To show the efficiency of purposed predictive model different FIR filters are designed and tested through similar data. Wind speed data have been collected during the period January 1, 2009 to December 31, 2009 from Casella automatic weather station at Plymouth. It is observed that 2-D FIR filters act more accurately in comparison with 1-D conventional representations; however, their prediction ability varies considerably through different filter sizing.

  2. FIR: An Effective Scheme for Extracting Useful Metadata from Social Media.

    Science.gov (United States)

    Chen, Long-Sheng; Lin, Zue-Cheng; Chang, Jing-Rong

    2015-11-01

    Recently, the use of social media for health information exchange is expanding among patients, physicians, and other health care professionals. In medical areas, social media allows non-experts to access, interpret, and generate medical information for their own care and the care of others. Researchers paid much attention on social media in medical educations, patient-pharmacist communications, adverse drug reactions detection, impacts of social media on medicine and healthcare, and so on. However, relatively few papers discuss how to extract useful knowledge from a huge amount of textual comments in social media effectively. Therefore, this study aims to propose a Fuzzy adaptive resonance theory network based Information Retrieval (FIR) scheme by combining Fuzzy adaptive resonance theory (ART) network, Latent Semantic Indexing (LSI), and association rules (AR) discovery to extract knowledge from social media. In our FIR scheme, Fuzzy ART network firstly has been employed to segment comments. Next, for each customer segment, we use LSI technique to retrieve important keywords. Then, in order to make the extracted keywords understandable, association rules mining is presented to organize these extracted keywords to build metadata. These extracted useful voices of customers will be transformed into design needs by using Quality Function Deployment (QFD) for further decision making. Unlike conventional information retrieval techniques which acquire too many keywords to get key points, our FIR scheme can extract understandable metadata from social media.

  3. Tropical Montane Cloud Forests: Hydrometeorological variability in three neighbouring catchments with different forest cover

    Science.gov (United States)

    Ramírez, Beatriz H.; Teuling, Adriaan J.; Ganzeveld, Laurens; Hegger, Zita; Leemans, Rik

    2017-09-01

    Mountain areas are characterized by a large heterogeneity in hydrological and meteorological conditions. This heterogeneity is currently poorly represented by gauging networks and by the coarse scale of global and regional climate and hydrological models. Tropical Montane Cloud Forests (TMCFs) are found in a narrow elevation range and are characterized by persistent fog. Their water balance depends on local and upwind temperatures and moisture, therefore, changes in these parameters will alter TMCF hydrology. Until recently the hydrological functioning of TMCFs was mainly studied in coastal regions, while continental TMCFs were largely ignored. This study contributes to fill this gap by focusing on a TMCF which is located on the northern eastern Andes at an elevation of 1550-2300 m asl, in the Orinoco river basin highlands. In this study, we describe the spatial and seasonal meteorological variability, analyse the corresponding catchment hydrological response to different land cover, and perform a sensitivity analysis on uncertainties related to rainfall interpolation, catchment area estimation and streamflow measurements. Hydro-meteorological measurements, including hourly solar radiation, temperature, relative humidity, wind speed, precipitation, soil moisture and streamflow, were collected from June 2013 to May 2014 at three gauged neighbouring catchments with contrasting TMCF/grassland cover and less than 250 m elevation difference. We found wetter and less seasonally contrasting conditions at higher elevations, indicating a positive relation between elevation and fog or rainfall persistence. This pattern is similar to that of other eastern Andean TMCFs, however, the study site had higher wet season rainfall and lower dry season rainfall suggesting that upwind contrasts in land cover and moisture can influence the meteorological conditions at eastern Andean TMCFs. Contrasting streamflow dynamics between the studied catchments reflect the overall system response

  4. Land use change effects on runoff generation in a humid tropical montane cloud forest region

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    L. E. Muñoz-Villers

    2013-04-01

    Full Text Available While tropical montane cloud forests (TMCF provide critical hydrological services to downstream regions throughout much of the humid tropics, catchment hydrology and impacts associated with forest conversion in these ecosystems remain poorly understood. Here, we compare the annual, seasonal and event-scale streamflow patterns and runoff generation processes of three neighbouring headwater catchments in central Veracruz (eastern Mexico with similar pedological and geological characteristics, but different land cover: old-growth TMCF (MAT, 20 yr-old naturally regenerating TMCF (SEC and a heavily grazed pasture (PAS. We used a 2 yr record of high resolution rainfall and stream flow data (2008–2010 in combination with stable isotope and chemical tracer data collected for a series of storms during a 6-week period of increasing antecedent wetness (wetting-up cycle. Our results showed that annual and seasonal streamflow patterns of the MAT and SEC were similar. In contrast, the PAS showed a 10% higher mean annual streamflow, most likely because of a lower rainfall interception. During the wetting-up cycle, storm runoff ratios increased at all three catchments (from 11 to 54% for the MAT, 7 to 52% for the SEC and 3 to 59% for the PAS. With the increasing antecedent wetness, hydrograph separation analysis showed progressive increases of pre-event water contributions to total stormflow (from 35 to 99% in the MAT, 26 to 92% in the SEC and 64 to 97% in the PAS. At all three sites, rainfall-runoff responses were dominated by subsurface flow generation processes for the majority of storms. However, for the largest and most intense storm (typically occurring once every 2 yr, sampled under wet antecedent conditions, the event water contribution in the PAS (34% on average was much higher than in the forests (5% on average, indicating that rainfall infiltration capacity of the PAS was exceeded. This result suggests that despite the high permeability of the

  5. Effects of habitat management treatments on plant community composition and biomass in a Montane wetland

    Science.gov (United States)

    Austin, J.E.; Keough, J.R.; Pyle, W.H.

    2007-01-01

    Grazing and burning are commonly applied practices that can impact the diversity and biomass of wetland plant communities. We evaluated the vegetative response of wetlands and adjacent upland grasslands to four treatment regimes (continuous idle, fall prescribed burning followed by idle, annual fall cattle grazing, and rotation of summer grazing and idle) commonly used by the U.S. Fish and Wildlife Service. Our study area was Grays Lake, a large, montane wetland in southeastern Idaho that is bordered by extensive wet meadows. We identified seven plant cover types, representing the transition from dry meadow to deep wetland habitats: mixed deep marsh, spikerush slough, Baltic rush (Juncus balticus), moist meadow, alkali, mesic meadow, and dry meadow. We compared changes in community composition and total aboveground biomass of each plant cover type between 1998, when all units had been idled for three years, and 1999 (1 yr post-treatment) and 2000 (2 yr post-treatment). Analysis using non-metric multidimensional scaling indicated that compositional changes varied among cover types, treatments, and years following treatment. Treatment-related changes in community composition were greatest in mixed deep marsh, Baltic rush, and mesic meadow. In mixed deep marsh and Baltic rush, grazing and associated trampling contributed to changes in the plant community toward more open water and aquatic species and lower dominance of Baltic rush; grazing and trampling also seemed to contribute to increased cover in mesic meadow. Changing hydrological conditions, from multiple years of high water to increasing drought, was an important factor influencing community composition and may have interacted with management treatments. Biomass differed among treatments and between years within cover types. In the wettest cover types, fall burning and grazing rotation treatments had greater negative impact on biomass than the idle treatment, but in drier cover types, summer grazing stimulated

  6. Seed germination of cirsium arvense and Lepidium latifolium: Implications for management of montane wetlands

    Science.gov (United States)

    Laubhan, M.K.; Shaffer, T.L.

    2006-01-01

    Cirsium arvense and Lepidium latifolium are species that can aggressively invade wetland margins and potentially reduce biodiversity and alter ecosystem function. Although expansion of these species primarily occurs via rhizomatous growth, seeds are thought to be important in initial establishment. We conducted this study to investigate differences in seed germination of C. arvense and L. latifolium in montane wetlands of Colorado and Wyoming, USA. We used germination chambers to simulate environmental conditions (photoperiod, day/night temperature) during three periods of the growing season at each site and evaluated seed germination in relation to three soil moisture levels and two soil depths. A combination of shallow (seed burial and wet conditions resulted in the greatest germination probability of C. arvense (x = 63.0%), 95% CI = 41.2-80.5%), whereas deep (2-3 cm) seed burial and saturated moisture conditions resulted in almost no germination (x?? = 0.3%, 95% CI = 0.1-1.3%). The maximum germination probability of 44.0% (CI = 28.1-61.4%) for L. latifolium also occurred in the shallow burial and wet treatment; however, only effects of seed burial were significant (P germination probability of deeply buried seeds was seeds. Our results suggest that each species has the ability to germinate at similar rates throughout the growing season and across a large portion of the moisture gradient. This suggests that management actions, including water-level manipulations, at any time during the growing season may stimulate germination. Although burial of seed to depths of 2-3 cm reduced the germination potential of both species, the use of mechanical implements may be problematic in established stands because new plants of both species easily sprout from root buds. Further, disturbance resulting from such actions diminishes the density and vigor of other plants already present, which may ultimately decrease the competitive resistance of the disturbed environment to

  7. Hillslope and stream connections to water tables in montane meadows of the southern Sierra Nevada, California

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    Conklin, M. H.; Lucas, R. G.

    2011-12-01

    Montane meadows are often areas of groundwater discharge. In this study we characterized the groundwater - surface water interactions of two meadow systems and their connectivity to the surrounding catchment . We analyzed groundwater elevation data in 24 wells in two meadows located in the southern Sierra Nevada. Well transects extended from the meadow centers near the stream, to the meadow edged, and into the adjacent forest-where wells were drilled into the weathered granite saprock layer. Water samples were collected from the monitoring wells and from streams associated with the meadow systems and analyzed for major ions and stable water isotopes. Ground water elevations in the monitoring wells were used to calculate daily evapotranspiration (ET) values. These values show that locations on the meadow slopes and near the meadow edges are losing water to the atmosphere at near potential evapotranspiration rates during the height of the growing season. ET signals from wells near the meadow streams are muted, likely due to the vegetation utilizing the available surface water at these locations. Wells installed in the saprock layer, outside of the meadow boundaries, show diurnal fluctuations in sync with fluctuations observed at the meadow edge. This trend persists after the meadow vegetation senesces, indicating that groundwater elevations in the meadow, especially near the meadow edge, are significantly influenced by the adjacent hillslope saprock layer and forest ET. Geochemical sampling results indicate that the meadow streams are predominantly fed by snowmelt in the spring and early summer, moving toward more influence from base flow in the late summer and early fall. Results from the geochemical analysis established the connections of the hillslope to the meadow water tables and of the meadow subsurface waters to the down-gradient streams. Our results indicate that the these meadows are directly connected to the shallow sub-surface processes in the up gradient

  8. Spatial requirements of free-ranging Huon tree kangaroos, Dendrolagus matschiei (Macropodidae, in upper montane forest.

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    Gabriel Porolak

    Full Text Available Tree kangaroos (Macropodidae, Dendrolagus are some of Australasia's least known mammals. However, there is sufficient evidence of population decline and local extinctions that all New Guinea tree kangaroos are considered threatened. Understanding spatial requirements is important in conservation and management. Expectations from studies of Australian tree kangaroos and other rainforest macropodids suggest that tree kangaroos should have small discrete home ranges with the potential for high population densities, but there are no published estimates of spatial requirements of any New Guinea tree kangaroo species. Home ranges of 15 Huon tree kangaroos, Dendrolagus matschiei, were measured in upper montane forest on the Huon Peninsula, Papua New Guinea. The home range area was an average of 139.6±26.5 ha (100% MCP; n = 15 or 81.8±28.3 ha (90% harmonic mean; n = 15, and did not differ between males and females. Home ranges of D. matschiei were 40-100 times larger than those of Australian tree kangaroos or other rainforest macropods, possibly due to the impact of hunting reducing density, or low productivity of their high altitude habitat. Huon tree kangaroos had cores of activity within their range at 45% (20.9±4.1 ha and 70% (36.6±7.5 ha harmonic mean isopleths, with little overlap (4.8±2.9%; n = 15 pairs between neighbouring females at the 45% isopleth, but, unlike the Australian species, extensive overlap between females (20.8±5.5%; n = 15 pairs at the complete range (90% harmonic mean. Males overlapped each other and females to a greater extent than did pairs of females. From core areas and overlap, the density of female D. matschiei was one per 19.4 ha. Understanding the cause of this low density is crucial in gaining greater understanding of variations in density of tree kangaroos across the landscape. We consider the potential role of habitat fragmentation, productivity and hunting pressure in limiting tree kangaroo

  9. Water balances of old-growth and regenerating montane cloud forests in central Veracruz, Mexico

    Science.gov (United States)

    Muñoz-Villers, L. E.; Holwerda, F.; Gómez-Cárdenas, M.; Equihua, M.; Asbjornsen, H.; Bruijnzeel, L. A.; Marín-Castro, B. E.; Tobón, C.

    2012-09-01

    SummaryThis paper compares the water budgets of two adjacent micro-catchments covered by mature (MAT) and 20-year-old secondary (SEC) lower montane cloud forests, respectively, in central Veracruz, Mexico over a 2-year period. Rainfall (P) and streamflow (Q) were measured continuously, whereas dry canopy evaporation (transpiration Et), wet canopy evaporation (rainfall interception I), and cloud water interception (CWI) were quantified using a combination of field measurements and modeling. Mean annual P was 3467 mm, of which typically 80% fell during the wet season (May-October). Fog interception occurred exclusively during the dry season (November-April), and was ⩽2% of annual P for both forests. Rainfall interception loss was dominated by post-event evaporation of intercepted water rather than by within-event evaporation. Therefore, the higher overall I (i.e. including CWI) by the MAT (16% of P vs. 8% for the SEC) reflects a higher canopy storage capacity, related in turn to higher leaf area index and greater epiphyte biomass. Annual Et totals derived from sapflow measurements were nearly equal for the MAT and SEC (˜790 mm each). Total annual water yield calculated as P minus (Et + I) was somewhat higher for the SEC (2441 mm) than for the MAT (2077 mm), and mainly reflects the difference in I. Mean annual Q was also higher for the SEC (1527 mm) than for the MAT (1338 mm), and consisted mostly of baseflow (˜90%). Baseflow recession rates were nearly equal between the two forests, as were stormflow coefficients (4% and 5% for MAT and SEC, respectively). The very low runoff response to rainfall is attributed to the high infiltration and water retention capacities of the volcanic soils throughout the ˜2 m deep profile. The water budget results indicate that ˜875 and 700 mm year-1 leave the SEC and MAT as deep groundwater leakage, which is considered plausible given the fractured geology in the study area. It is concluded that 20 years of natural regeneration

  10. Tropical montane forest conversion affects spatial and temporal nitrogen dynamics in Kenyan headwater catchment

    Science.gov (United States)

    Jacobs, Suzanne; Weeser, Björn; Breuer, Lutz; Butterbach-Bahl, Klaus; Guzha, Alphonce; Rufino, Mariana

    2017-04-01

    Deforestation and land use change (LUC) are often stated as major contributors to changes in water quality, although other catchment characteristics such as topography, geology and climate can also play a role. Understanding how stream water chemistry is affected by LUC is essential for sustainable water management and land use planning. However, there is often a lack of reliable data, especially in less studied regions such as East Africa. This study focuses on three sub-catchments (27-36 km2) with different land use types (natural forest, smallholder agriculture and tea/tree plantations) nested in a 1023 km2 headwater catchment in the Mau Forest Complex, Kenya's largest closed-canopy indigenous tropical montane forest. In the past decades approx. 25% of the natural forest was lost due to land use change. We studied seasonal, diurnal and spatial patterns of total dissolved nitrogen (TDN), nitrate (NO3-N) and dissolved organic nitrogen (DON) using a combination of high-resolution in-situ measurements, bi-weekly stream water samples and spatial sampling campaigns. Multiple linear regression analysis of the spatial data indicates that land use shows a strong influence on TDN and nitrate, while DON is more influenced by precipitation. Highest TDN and nitrate concentrations are found in tea plantations, followed by smallholder agriculture and natural forest. This ranking does not change throughout the year, though concentrations of TDN and nitrate are respectively 27.6 and 25.4% lower in all catchments during the dry season. Maximum Overlap Discrete Wavelet Transform (MODWT) analysis of the high resolution nitrate data revealed a seasonal effect on diurnal patterns in the natural forest catchment, where the daily peak shifts from early morning in the wet season to mid-afternoon in the dry season. The smallholder and tea catchment do not exhibit clear diurnal patterns. The results suggest that land use affects dissolved nitrogen concentrations, leading to higher N

  11. Pollen-based temperature and precipitation inferences for the montane forest of Mt. Kilimanjaro during the last Glacial and the Holocene

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    L. Schüler

    2014-01-01

    Full Text Available The relationship between modern pollen-rain taxa and measured climate variables was explored along the elevational gradient of the southern slope of Mt. Kilimanjaro, Tanzania. Pollen assemblages in 28 pollen traps positioned on 14 montane forest vegetation plots were identified and their relationship with climate variables was examined using multivariate statistical methods. Canonical correspondence analysis revealed that the mean annual temperature, mean annual precipitation and minimum temperature each account for significant fractions of the variation in pollen taxa. A training set of 107 modern pollen taxa was used to derive temperature and precipitation transfer functions based on pollen subsets using weighted-averaging-partial-least-squares (WA-PLS techniques. The transfer functions were then applied to a fossil pollen record from the montane forest of Mt. Kilimanjaro and the climate parameter estimates for the Late Glacial and the Holocene on Mt. Kilimanjaro were inferred. Our results present the first quantitatively reconstructed temperature and precipitation estimates for Mt Kilimanjaro and give highly interesting insights into the past 45 000 yr of climate dynamics in tropical East Africa. The climate reconstructions are consistent with the interpretation of pollen data in terms of vegetation and climate history of afro-montane forest in East Africa. Minimum temperatures above the frostline as well as increased precipitation turn out to be crucial for the development and expansion of montane forest during the Holocene. In contrast, consistently low minimum temperatures as well as about 25% drier climate conditions prevailed during the pre LGM, which kept the montane vegetation composition in a stable state. In prospective studies, the quantitative climate reconstruction will be improved by additional modern pollen rain data, especially from lower elevations with submontane dry forests and colline savanna vegetation in order to extend

  12. High-angular resolution observations towards OMC-2 FIR 4: Dissecting an intermediate-mass protocluster

    Science.gov (United States)

    López-Sepulcre, A.; Taquet, V.; Sánchez-Monge, Á.; Ceccarelli, C.; Dominik, C.; Kama, M.; Caux, E.; Fontani, F.; Fuente, A.; Ho, P. T. P.; Neri, R.; Shimajiri, Y.

    2013-08-01

    Context. Intermediate-mass stars are an important ingredient of our Galaxy and a key to understanding how high- and low-mass stars form in clusters. One of the closest known young intermediate-mass protoclusters is OMC-2 FIR 4, which is located at a distance of 420 pc in Orion. This region is one of the few where the complete 500-2000 GHz spectrum has been observed with the heterodyne spectrometer HIFI on board the Herschel satellite, and unbiased spectral surveys at 0.8, 1, 2, and 3 mm have been obtained with the JCMT and IRAM 30-m telescopes. Aims: We aim to disentangle the core multiplicity, to investigate the morphology of this region in order to study the formation of a low- and intermediate-mass protostar cluster, and to aid in interpretation of the single-dish line profiles already in our hands. Methods: We used the IRAM Plateau de Bure Interferometer to image OMC-2 FIR 4 in the 2-mm continuum emission, as well as in DCO+(2-1), DCN(2-1), C34S(3-2), and several CH3OH lines. In addition, we analysed observations of the NH3(1, 1) and (2, 2) inversion transitions that used the Very Large Array of the NRAO. The resulting maps have an angular resolution that allows us to resolve structures of 5″, which is equivalent to ~2000 AU. Results: Our observations reveal three spatially resolved sources within OMC-2 FIR 4, of one or several solar masses each, with hints of further unresolved substructure within them. Two of these sources have elongated shapes and are associated with dust continuum emission peaks, thus likely containing at least one molecular core each. One of them also displays radio continuum emission, which may be attributed to a young B3-B4 star that dominates the overall luminosity output of the region. The third identified source displays a DCO+(2-1) emission peak and weak dust continuum emission. Its higher abundance of DCO+ relative to the other two regions suggests a lower temperature, hence its possible association with either a younger low

  13. Structure and productivity of mixed spruce and fir forests on Mt. Kopaonik

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    Šljukić Biljana

    2017-01-01

    Full Text Available The subject of this research are mixed forests of spruce and fir in the area of NP Kopaonik, which belong to the community of spruce and fir - Abieti-Piceetum abietis Mišić et Popović, 1978. The basis for the study of the structural development and production potential of these forests are data from 12 sample plots, with the average size of 0.18 ha. In terms of coenoecological affiliation all the sample plots belong to the group of ecological units - forests of spruce and fir (Abieti-Piceetum abietis, Mišić et Popović, 1978 on acid brown and brown podzolic soils, which are differentiated into 5 ecological units: Abieti-Piceetum abietis oxalidetosum on brown podzolic soil, Abieti-Piceetum abietis oxalidetosum on acid brown soil, Abieti-Piceetum abietis vaccinietosum on brown podzolic soil, Abieti-Piceetum abietis typicum on brown podzolic soil and Abieti-Piceetum abietis Dr.ymetosum on brown pozolic soil. In structural terms, these forests are characterized by very diverse structural forms, ranging from the structure of even-aged stands to typical multi-storey, unevenaged-aged stands. The form of cumulative curves of tree distribution is in most cases determined by spruce as the dominant species. At the same time, thin and medium-thick trees dominate, while the presence of stems with large dimensions is minimal. The average volume of these forestse is 777 m3•ha-1, with a mixture ratio of 0.7: 0.3 in favor of spruce. The average value of the current volume increment is 14 m3•ha-1, with a 68% share of spruce and 32% of fir. The percentage of increment ranges from 1.6% to 2.5% in all sample plots and is somewhat higher for fir. The site potential, stand characteristics and relations among the tree species have resulted in structural complexity, high productivity and ecological stability of these forests. Therefore, future forest management should avoid radical measures and procedures that would violate the established relationships and

  14. Salvage logging in the montane ash eucalypt forests of the Central Highlands of Victoria and its potential impacts on biodiversity.

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    Lindenmayer, D B; Ought, K

    2006-08-01

    The two major forms of disturbance in the montane ash eucalypt forests of the Central Highlands of Victoria (southeastern Australia) are clearfell logging and unplanned wildfires. Since the 1930s wildfire has been followed by intensive and extensive salvage-logging operations, which may proceed for many years after a wildfire has occurred. Although applied widely, the potential effects of salvage logging on native flora and fauna have been poorly studied. Our data indicate that the abundance of large trees with hollows is significantly reduced in forests subject to salvage harvesting. This has implications for thepersistence of an array of such cavity-using vertebrates as the endangered arboreal marsupial, Leadbeater's possum (Gymnobelidues leadbeateri). Salvage logging also reduces the prevalence of multiaged montane ash forests--places that typically support the highest diversity of arboreal marsupials and forest birds. Limited research has been conducted on the effects of salvage logging on plants; thus, we constructed hypotheses about potential impacts for further testing based on known responses to clearfell logging and key life history attributes. We predict many species, such as vegetatively resprouting tree ferns, will decline, as they do after clearfelling. We also suggest that seed regenerators, which typically regenerate well after fire or conventional clearfelling, will decline after salvage logging because the stimulation for germination (fire) takes place prior to mechanical disturbance (logging). Understoryplant communities in salvage-logged areas will be dominated by a smaller suite of species, and those that are wind dispersed, have viable soil-stored seed remaining after salvage logging, or have deep rhizomes are likely to be advantaged. We recommend the following improvements to salvage-logging policies that may better incorporate conservation needs in Victorian montane ash forests: (1) exemption of salvage logging from some areas (e.g., old

  15. Nitrate Removal Along a Colorado Montane Headwater Stream: the Role of Bidirectional Hydrologic Exchange at Reach to Catchment Scales

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    Smull, E. M.; Gooseff, M. N.

    2015-12-01

    Bidirectional hydrologic exchanges between streams and aquifers can influence nutrient concentrations (physical influx/efflux via gaining/losing water), and/or can facilitate biogeochemical cycling (physical and biological processes). Such exchanges therefore act to influence nutrient fate and transport, and have not yet been captured and incorporated into our understanding of stream nutrient retention and export. Along Colorado's Front Range, research in alpine and subalpine catchments has documented consistent increases in nitrate export, likely due to increased nitrogen deposition from industrialization and fertilization in eastern Colorado. The state of montane zone catchments with respect to their ability to cycle nitrate is not as well understood, however, and such ecosystems have complex hydrologic regimes relative to alpine areas. We applied a fully informed hydrologic mass balance model and nitrate mass balance model that include gross gains and gross losses (bidirectional exchanges) along a 1000 m study reach, to better understand physical and biological nitrate removal for a Colorado montane zone catchment, Lower Gordon Gulch. We collected data during five synoptic stream tracer and sampling campaigns along our study reach during the 2014-2015 water year, and installed wells along the north-facing and south-facing riparian corridor to capture changing water tables. Four distinct hydrologic regimes are captured in our results, including two experiments during baseflow, one experiment following snowmelt, one experiment following late-spring rainfall, and one experiment during the start of the seasonal hydrograph recession in mid-summer. Results show a transition from hydrologic sources of nitrate following snowmelt, to biological sources during rainfall, to biological removal during summer, and finally to hydrologic removal during baseflow. Our findings also corroborate earlier work in montane zone streams that shows preferential flow on south

  16. What is baseflow? Integrating hydrometric and hydrochemical methods to assess dynamic groundwater contributions to montane streams under low flows

    Science.gov (United States)

    Blumstock, Maria; Tetzlaff, Doerthe; Nuetzmann, Gunnar; Malcolm, Iain; Soulsby, Chris

    2014-05-01

    We monitored changing groundwater-surface water interactions through an unusual prolonged dry spell in the Scottish Highlands in summer 2013. The period between May and September saw a 20 year return period drought, these changing hydrometric conditions were monitored in an intensively instrumented 3.2km2 catchment. This montane catchment is underlain by granite and metasediments and has extensive cover of diverse drift deposits. The drought saw slight declines in soil moisture and groundwater levels in valley bottom wetlands but major, rapid declines on steeper upland slopes. This coincided with gradual declines in discharge, however the chemical composition of reducing stream flows showed marked temporal variation which differed spatially. Synoptic hydrogeochemical surveys were carried out on four occasions as flows declined. Each survey repeated sampling of 30 sites on the 3km long stream network as the catchment transitioned from wet to dry conditions. Samples were analysed for major anions, cations and water isotopes. Initial surveys just after the last winter rain showed relatively homogenous stream chemistry, dominated by drainage from acidic peat soils in valley bottom areas. Stream chemistry became increasingly enriched with weathering-derived solutes (e.g. alkalinity, Ca, Mg etc.) as flows declined and groundwater contributions to flow increases. Repeat surveys showed an evolving chemistry of groundwater contributions as discharge from smaller shallower stores sequentially depleted. However, these changes showed marked spatial variability reflecting geochemical differences in the bedrock geology and the distribution of drift deposits. Importantly, much more dynamism was observed than previously thought with diverse montane groundwater bodies contributing to flows differentially during the recession. In addition, strong topographic shading in this montane catchment results in spatially variable radiation inputs and evapotranspiration. This is reflected in

  17. Stand Composition, Tree Proximity and Size Have Minimal Effects on Leaf Function of Coexisting Aspen and Subalpine Fir.

    Science.gov (United States)

    Rhodes, Aaron C; Barney, Trevor; St Clair, Samuel B

    2016-01-01

    Forest structural heterogeneity due to species composition, spatial relationships and tree size are widely studied patterns in forest systems, but their impacts on tree function are not as well documented. The objective of this study was to examine how stand composition, tree proximity relationships and tree size influence the leaf functional traits of aspen, an early successional species, and subalpine fir, a climax species. We measured foliar nutrients, nonstructural carbohydrates (aspen only), defense chemistry and xylem water potential of aspen and subalpine fir trees in three size classes growing in close proximity or independently from other trees under three stand conditions: aspen dominant, aspen-conifer mixed, and conifer dominant stands. Close proximity of subalpine fir to aspen reduced aspen's storage of starch in foliar tissue by 17% suggesting that competition between these species may have small effects on carbon metabolism in aspen leaves. Simple sugar (glucose + sucrose) concentrations in aspen leaves were slightly higher in larger aspen trees than smaller trees. However, no differences were found in stem water potential, foliar concentrations of nitrogen, phosphorus, or secondary defense chemicals of aspen or subalpine fir across the gradients of stand composition, tree proximity or tree size. These results suggest that mechanisms of coexistence allow both aspen and subalpine fir to maintain leaf function across a wide range of stand structural characteristics. For aspen, resource sharing through its clonal root system and high resource storage capacity may partially contribute to its functional stability in mixed aspen-conifer stands.

  18. Diameter Growth, Biological Rotation Age and Biomass of Chinese Fir in Burning and Clearing Site Preparations in Subtropical China

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    Hua Zhou

    2016-08-01

    Full Text Available Sustained forest management of Cunninghamia lanceolata (Chinese fir plantations in subtropical China is restricted by the limited availability of quantitative data. This study combines inventory data and tree-ring analysis of Chinese fir from natural and plantation forests that were subjected to controlled burning or brush clearing site preparations. Inter-annual variation of Chinese fir tree-ring widths were measured for the controlled burning, brush clearing and natural forest sites. The mean annual diametric growth of Chinese fir was 0.56 cm·year−1 for the natural forest, 0.80 cm·year−1 for the brush clearing site and 1.10 cm·year−1 for the controlled burning site. The time needed to reach the minimum cutting/logging diameter of 15 cm was 14 years in the controlled burning site, 19 years in the brush clearing site and >40 years in the natural forest. The biological rotation ages for the burning, cutting and natural forest sites were 15, 26 and >100 years, respectively. The total aboveground biomasses for the burning and clearing sites were 269.8 t·ha−1 and 252 t·ha−1, respectively. These results suggest that the current 25-year cutting cycle greatly underestimates the growth rate of Chinese fir plantations.

  19. In vivo evaluation of the effect of stimulus distribution on FIR statistical efficiency in event-related fMRI.

    Science.gov (United States)

    Jansma, J Martijn; de Zwart, Jacco A; van Gelderen, Peter; Duyn, Jeff H; Drevets, Wayne C; Furey, Maura L

    2013-05-15

    Technical developments in MRI have improved signal to noise, allowing use of analysis methods such as Finite impulse response (FIR) of rapid event related functional MRI (er-fMRI). FIR is one of the most informative analysis methods as it determines onset and full shape of the hemodynamic response function (HRF) without any a priori assumptions. FIR is however vulnerable to multicollinearity, which is directly related to the distribution of stimuli over time. Efficiency can be optimized by simplifying a design, and restricting stimuli distribution to specific sequences, while more design flexibility necessarily reduces efficiency. However, the actual effect of efficiency on fMRI results has never been tested in vivo. Thus, it is currently difficult to make an informed choice between protocol flexibility and statistical efficiency. The main goal of this study was to assign concrete fMRI signal to noise values to the abstract scale of FIR statistical efficiency. Ten subjects repeated a perception task with five random and m-sequence based protocol, with varying but, according to literature, acceptable levels of multicollinearity. Results indicated substantial differences in signal standard deviation, while the level was a function of multicollinearity. Experiment protocols varied up to 55.4% in standard deviation. Results confirm that quality of fMRI in an FIR analysis can significantly and substantially vary with statistical efficiency. Our in vivo measurements can be used to aid in making an informed decision between freedom in protocol design and statistical efficiency.

  20. An Innovations-Based Noise Cancelling Technique on Inverse Kepstrum Whitening Filter and Adaptive FIR Filter in Beamforming Structure

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    Jinsoo Jeong

    2011-06-01

    Full Text Available This paper presents an acoustic noise cancelling technique using an inverse kepstrum system as an innovations-based whitening application for an adaptive finite impulse response (FIR filter in beamforming structure. The inverse kepstrum method uses an innovations-whitened form from one acoustic path transfer function between a reference microphone sensor and a noise source so that the rear-end reference signal will then be a whitened sequence to a cascaded adaptive FIR filter in the beamforming structure. By using an inverse kepstrum filter as a whitening filter with the use of a delay filter, the cascaded adaptive FIR filter estimates only the numerator of the polynomial part from the ratio of overall combined transfer functions. The test results have shown that the adaptive FIR filter is more effective in beamforming structure than an adaptive noise cancelling (ANC structure in terms of signal distortion in the desired signal and noise reduction in noise with nonminimum phase components. In addition, the inverse kepstrum method shows almost the same convergence level in estimate of noise statistics with the use of a smaller amount of adaptive FIR filter weights than the kepstrum method, hence it could provide better computational simplicity in processing. Furthermore, the rear-end inverse kepstrum method in beamforming structure has shown less signal distortion in the desired signal than the front-end kepstrum method and the front-end inverse kepstrum method in beamforming structure.

  1. Gap Dynamics and Tree Species Diversity in a Tropical Montane Rain Forest of Hainan Island,China

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Based on investigation of 53 gaps and 25 quadrats (15m×15m each) of non-gap closed stand in an old-growth tropical montane rain forest of Hainan Island, China, canopy disturbance regimes and gap regeneration were studied. Gaps were elliptical in horizontal form, the ratio of long axis /short axis was about 1.4. Percentage of expanded gaps (EG) and canopy gaps (CG) area in the landscape were 53.5% and 25.2% respectively. EG ranged from 31.4 m2 to 488.2m2 and CG/rom 14.9m2 to 354.2m2, their average sizes ...

  2. Impacts of climate and management on water balance and nitrogen leaching from montane grassland soils

    Science.gov (United States)

    Fu, Jin; Gasche, Rainer; Wang, Na; Lu, Haiyan; Butterbach-Bahl, Klaus; Kiese, Ralf

    2017-04-01

    The impacts of climate and management on the water balance and nutrient leaching of montane grasslands have rarely been investigated, though such ecosystems may represent a major source for ground and surface water nitrates. In this study nitrogen (nitrate, ammonium, dissolved organic nitrogen) and dissolved organic carbon leaching as well as water balance components (precipitation, evapotranspiration, and groundwater recharge) were quantified (2012-2014) by means of replicated (N=3 per site/ treatment) measurements of weighable grassland lysimeters (1 m2 area, 1.2 m soil depth) at three sites (E860: 860 m a.s.l., E770: 770 m a.s.l. and E600: 600 m a.s.l.) in the pre-alpine region of S-Germany. Two grassland management strategies were investigated: a) intensive management with 5 cuts per year and cattle slurry application rates of 280 kg N ha-1 yr-1, and b) extensive management with 3 cuts per year and cattle slurry application rates of 56 kg N ha-1 yr-1. Our results show that at E600, the site with highest air temperature (8.6 °C) and lowest precipitation (981.9 mm), evapotranspiration losses were 100.7 mm higher as at the E860 site, i.e. the site with lowest mean annual air temperature (6.5 °C) and highest precipitation (1359.3 mm). On the other hand groundwater recharge was substantial lower at E600 (-440.9 mm) as compared to E860. Compared to climate, impacts of grassland management on water balance components were negligible. However, intensive management significantly increased mean total nitrogen leaching rates across sites as compared to extensive management from 2.6 kg N ha-1 year-1 (range: 0.5-6.0 kg N ha-1 year-1) to 4.8 kg N ha-1 year-1 (range: 0.9-12.9 kg N ha-1 year-1). N leaching losses were dominated by nitrate (64.7 %) and equally less by ammonium (14.6 %) and DON (20.7 %). The rather low rates of N leaching (0.8 - 6.9 % of total applied N) suggest a highly efficient nitrogen uptake by plants as measured by plant total N content at harvest

  3. Groundwater-surface water interactions in montane meadows of the Sierra Nevada, California

    Science.gov (United States)

    Lucas, R. G.; Conklin, M. H.

    2012-12-01

    center data indicate groundwater discharge for the entirety of the summer growing season—long after the adjacent forest soils have dried out. Analysis of the geochemical data show that major ion concentrations vary little within the individual wells but vary from the edge of the meadow to the center. Stream water samples show surface flow is dominated by snow melt in the spring and is influenced more by subsurface flow as the growing season progresses. Groundwater discharges into the center of the meadows, long after the soils the adjacent Forests have dried out. This is consistent with the results from our geochemical analysis that suggests the surface water leaving the meadow systems is more influenced by subsurface flow later in the summer. Consistent groundwater discharge, with little variation in the geochemical profile of the groundwater, suggests a shallow groundwater source that is not being fully utilized by the adjacent forest landscape. These montane meadow systems provide a window for investigating groundwater surface water interactions in the catchments of the Southern Sierra Critical Zone Observatory.

  4. The potential negative impacts of global climate change on tropical montane cloud forests

    Science.gov (United States)

    Foster, Pru

    2001-10-01

    Nearly every aspect of the cloud forest is affected by regular cloud immersion, from the hydrological cycle to the species of plants and animals within the forest. Since the altitude band of cloud formation on tropical mountains is limited, the tropical montane cloud forest occurs in fragmented strips and has been likened to island archipelagoes. This isolation and uniqueness promotes explosive speciation, exceptionally high endemism, and a great sensitivity to climate. Global climate change threatens all ecosystems through temperature and rainfall changes, with a typical estimate for altitude shifts in the climatic optimum for mountain ecotones of hundreds of meters by the time of CO 2 doubling. This alone suggests complete replacement of many of the narrow altitude range cloud forests by lower altitude ecosystems, as well as the expulsion of peak residing cloud forests into extinction. However, the cloud forest will also be affected by other climate changes, in particular changes in cloud formation. A number of global climate models suggest a reduction in low level cloudiness with the coming climate changes, and one site in particular, Monteverde, Costa Rica, appears to already be experiencing a reduction in cloud immersion. The coming climate changes appear very likely to upset the current dynamic equilibrium of the cloud forest. Results will include biodiversity loss, altitude shifts in species' ranges and subsequent community reshuffling, and possibly forest death. Difficulties for cloud forest species to survive in climate-induced migrations include no remaining location with a suitable climate, no pristine location to colonize, migration rates or establishment rates that cannot keep up with climate change rates and new species interactions. We review previous cloud forest species redistributions in the paleo-record in light of the coming changes. The characteristic epiphytes of the cloud forest play an important role in the light, hydrological and nutrient

  5. Nutrient addition modifies phosphatase activities along an altitudinal gradient in a tropical montane forest in Southern Ecuador

    Directory of Open Access Journals (Sweden)

    Karla eDietrich

    2016-02-01

    Full Text Available Atmospheric nutrient deposition and climate change are expected to endanger the diversity of tropical forest ecosystems. Nitrogen (N deposition might influence nutrient fluxes beyond the N cycle by a concomitant increased demand for other nutritional elements such as phosphorus (P. Organisms might respond to the increased P demand by enhanced activity of enzymes involved in releasing inorganic P from organic matter (OM. Our aims were to assess the effect of i climate shifts (approximated by an altitudinal gradient, and ii nutrient addition (N, P, N+P on phosphatase activity (PA in organic layer and mineral soil of a tropical montane rainforest in Southern Ecuador. A nutrient manipulation experiment (NUMEX was set up along an altitudinal gradient (1000, 2000, and 3000 m a.s.l.. We determined PA and inorganic and total P concentrations. PA at 1000 m was significantly lower (mean ± standard error: 48 ± 20 µmol p-NP g-1 dm h-1 as compared to 2000 m and 3000 m (119 ± 11 and 137 ± 19, respectively. One explanation might be that very rapid decomposition of OM at 1000 m results in very thin organic layers reducing the stabilization of enzymes and thus, resulting in leaching loss of enzymes under the humid tropical climate. We found no effect of N addition on PA neither in the organic layer nor in mineral soil, probably because of the low nutrient addition rates that showed ambiguous results so far on productivity measures as a proxy for P demand. In the organic layers of P and N+P treatments, we found decreased PA and increased concentrations of inorganic P. This indicates that the surplus of inorganic P reduced the biosynthesis of phosphatase enzymes. PA in megadiverse montane rainforests is likely to be unaffected by increased atmospheric N deposition but reduced upon atmospheric P deposition.

  6. Nutrient addition modifies phosphatase activities along an altitudinal gradient in a tropical montane forest in Southern Ecuador

    Science.gov (United States)

    Dietrich, Karla; Spoeri, Elena; Oelmann, Yvonne

    2016-02-01

    Atmospheric nutrient deposition and climate change are expected to endanger the diversity of tropical forest ecosystems. Nitrogen (N) deposition might influence nutrient fluxes beyond the N cycle by a concomitant increased demand for other nutritional elements such as phosphorus (P). Organisms might respond to the increased P demand by enhanced activity of enzymes involved in releasing inorganic P from organic matter (OM). Our aims were to assess the effect of i) climate shifts (approximated by an altitudinal gradient), and ii) nutrient addition (N, P, N+P) on phosphatase activity (PA) in organic layer and mineral soil of a tropical montane rainforest in Southern Ecuador. A nutrient manipulation experiment (NUMEX) was set up along an altitudinal gradient (1000, 2000, and 3000 m a.s.l.). We determined PA and inorganic and total P concentrations. PA at 1000 m was significantly lower (mean ± standard error: 48 ± 20 µmol p-NP g-1 dm h-1) as compared to 2000 m and 3000 m (119 ± 11 and 137 ± 19, respectively). One explanation might be that very rapid decomposition of OM at 1000 m results in very thin organic layers reducing the stabilization of enzymes and thus, resulting in leaching loss of enzymes under the humid tropical climate. We found no effect of N addition on PA neither in the organic layer nor in mineral soil, probably because of the low nutrient addition rates that showed ambiguous results so far on productivity measures as a proxy for P demand. In the organic layers of P and N+P treatments, we found decreased PA and increased concentrations of inorganic P. This indicates that the surplus of inorganic P reduced the biosynthesis of phosphatase enzymes. PA in megadiverse montane rainforests is likely to be unaffected by increased atmospheric N deposition but reduced upon atmospheric P deposition.

  7. Significance of pre-Quaternary climate change for montane species diversity: insights from Asian salamanders (Salamandridae: Pachytriton).

    Science.gov (United States)

    Wu, Yunke; Wang, Yuezhao; Jiang, Ke; Hanken, James

    2013-01-01

    Despite extensive focus on the genetic legacy of Pleistocene glaciation, impacts of earlier climatic change on biodiversity are poorly understood. Because amphibians are highly sensitive to variations in precipitation and temperature, we use a genus of Chinese montane salamanders (Salamandridae: Pachytriton) to study paleoclimatic change in East Asia, which experienced intensification of its monsoon circulation in the late Miocene associated with subsequent Pliocene warming. Using both nuclear and mitochondrial DNA sequences, we reconstruct the species tree under a coalescent model and demonstrate that all major lineages originated before the Quaternary. Initial speciation within the genus occurred after the summer monsoon entered a stage of substantial intensification. Heavy summer precipitation established temporary water connectivity through overflows between adjacent stream systems, which may facilitate geographic range expansion by aquatic species such as Pachytriton. Species were formed in allopatry likely through vicariant isolation during or after range expansion. To evaluate the influence of Pliocene warming on these cold-adapted salamanders, we construct a novel temperature buffer-zone model, which suggests widespread physiological stress or even extinction during the warming period. A significant deceleration of species accumulation rate is consistent with Pliocene range contraction, which affected P. granulosus and P. archospotus the most because they lack large temperature buffer zones. In contrast, demographic growth occurred in species for which refugia persist. The buffer-zone model reveals the Huangshan Mountain as a potential climatic refugium, which is similar to that found for other East Asian organisms. Our approach can incorporate future climatic data to evaluate the potential impact of ongoing global warming on montane species (particularly amphibians) and to predict possible population declines.

  8. Current analogues of future climate indicate the likely response of a sensitive montane tropical avifauna to a warming world.

    Directory of Open Access Journals (Sweden)

    Alexander S Anderson

    Full Text Available Among birds, tropical montane species are likely to be among the most vulnerable to climate change, yet little is known about how climate drives their distributions, nor how to predict their likely responses to temperature increases. Correlative models of species' environmental niches have been widely used to predict changes in distribution, but direct tests of the relationship between key variables, such as temperature, and species' actual distributions are few. In the absence of historical data with which to compare observations and detect shifts, space-for-time substitutions, where warmer locations are used as analogues of future conditions, offer an opportunity to test for species' responses to climate. We collected density data for rainforest birds across elevational gradients in northern and southern subregions within the Australian Wet Tropics (AWT. Using environmental optima calculated from elevational density profiles, we detected a significant elevational difference between the two regions in ten of 26 species. More species showed a positive (19 spp. than negative (7 spp. displacement, with a median difference of ∼80.6 m across the species analysed that is concordant with that expected due to latitudinal temperature differences (∼75.5 m. Models of temperature gradients derived from broad-scale climate surfaces showed comparable performance to those based on in-situ measurements, suggesting the former is sufficient for modeling impacts. These findings not only confirm temperature as an important factor driving elevational distributions of these species, but also suggest species will shift upslope to track their preferred environmental conditions. Our approach uses optima calculated from elevational density profiles, offering a data-efficient alternative to distribution limits for gauging climate constraints, and is sensitive enough to detect distribution shifts in this avifauna in response to temperature changes of as little as 0

  9. Height-diameter allometry and above ground biomass in tropical montane forests: Insights from the Albertine Rift in Africa

    Science.gov (United States)

    Boyemba, Faustin; Lewis, Simon; Nabahungu, Nsharwasi Léon; Calders, Kim; Zapfack, Louis; Riera, Bernard; Balegamire, Clarisse; Cuni-Sanchez, Aida

    2017-01-01

    Tropical montane forests provide an important natural laboratory to test ecological theory. While it is well-known that some aspects of forest structure change with altitude, little is known on the effects of altitude on above ground biomass (AGB), particularly with regard to changing height-diameter allometry. To address this we investigate (1) the effects of altitude on height-diameter allometry, (2) how different height-diameter allometric models affect above ground biomass estimates; and (3) how other forest structural, taxonomic and environmental attributes affect above ground biomass using 30 permanent sample plots (1-ha; all trees ≥ 10 cm diameter measured) established between 1250 and 2600 m asl in Kahuzi Biega National Park in eastern Democratic Republic of Congo. Forest structure and species composition differed with increasing altitude, with four forest types identified. Different height-diameter allometric models performed better with the different forest types, as trees got smaller with increasing altitude. Above ground biomass ranged from 168 to 290 Mg ha-1, but there were no significant differences in AGB between forests types, as tree size decreased but stem density increased with increasing altitude. Forest structure had greater effects on above ground biomass than forest diversity. Soil attributes (K and acidity, pH) also significantly affected above ground biomass. Results show how forest structural, taxonomic and environmental attributes affect above ground biomass in African tropical montane forests. They particularly highlight that the use of regional height-diameter models introduces significant biases in above ground biomass estimates, and that different height-diameter models might be preferred for different forest types, and these should be considered in future studies. PMID:28617841

  10. Height-diameter allometry and above ground biomass in tropical montane forests: Insights from the Albertine Rift in Africa.

    Science.gov (United States)

    Imani, Gérard; Boyemba, Faustin; Lewis, Simon; Nabahungu, Nsharwasi Léon; Calders, Kim; Zapfack, Louis; Riera, Bernard; Balegamire, Clarisse; Cuni-Sanchez, Aida

    2017-01-01

    Tropical montane forests provide an important natural laboratory to test ecological theory. While it is well-known that some aspects of forest structure change with altitude, little is known on the effects of altitude on above ground biomass (AGB), particularly with regard to changing height-diameter allometry. To address this we investigate (1) the effects of altitude on height-diameter allometry, (2) how different height-diameter allometric models affect above ground biomass estimates; and (3) how other forest structural, taxonomic and environmental attributes affect above ground biomass using 30 permanent sample plots (1-ha; all trees ≥ 10 cm diameter measured) established between 1250 and 2600 m asl in Kahuzi Biega National Park in eastern Democratic Republic of Congo. Forest structure and species composition differed with increasing altitude, with four forest types identified. Different height-diameter allometric models performed better with the different forest types, as trees got smaller with increasing altitude. Above ground biomass ranged from 168 to 290 Mg ha-1, but there were no significant differences in AGB between forests types, as tree size decreased but stem density increased with increasing altitude. Forest structure had greater effects on above ground biomass than forest diversity. Soil attributes (K and acidity, pH) also significantly affected above ground biomass. Results show how forest structural, taxonomic and environmental attributes affect above ground biomass in African tropical montane forests. They particularly highlight that the use of regional height-diameter models introduces significant biases in above ground biomass estimates, and that different height-diameter models might be preferred for different forest types, and these should be considered in future studies.

  11. Comparison of leaf anatomy and essential oils from Drimys brasiliensis Miers in a montane cloud forest in Itamonte, MG, Brazil.

    Science.gov (United States)

    Cruz, Bruna Paula da; de Castro, Evaristo Mauro; Cardoso, Maria das Graças; de Souza, Katiúscia Freire; Machado, Samísia Maria Fernandes; Pompeu, Patrícia Vieira; Fontes, Marco Aurélio Leite

    2014-12-01

    Drimys brasiliensis Miers is native to Brazil, where it is mainly found in montane forests and flooded areas in the South and Southeast regions of the country. The objectives of the present study were to compare the leaf anatomy and the chemical constitution of the essential oils from D. brasiliensis present in two altitude levels (1900 and 2100 m), in a Montane Cloud Forest, in Itamonte, MG, Brazil. A higher number of sclereids was observed in the mesophyll of the leaves at 1900 m altitude. At 2100 m, the formation of papillae was observed on the abaxial surface of the leaves, as well as an increase in the stomatal density and index, a reduction in leaf tissue thickness, an increase in the abundance of intercellular spaces in the mesophyll and an increase in stomatal conductance and in carbon accumulation in the leaves. Fifty-nine constituents have been identified in the oils, with the predominance of sesquiterpenes. Two trends could be inferred for the species in relation to its secondary metabolism and the altitude. The biosyntheses of sesquiterpene alcohols at 1900 m, and phenylpropanoids and epi-cyclocolorenone at 2100 m, were favored. D. brasiliensis presented a high phenotypic plasticity at the altitude levels studied. In relation to its leaf anatomy, the species showed adaptive characteristics, which can maximize the absorption of CO2 at 2100 m altitude, where a reduction in the partial pressure of this atmospheric gas occurs. Its essential oils presented promising compounds for the future evaluation of biological potentialities.

  12. [Microbial community and its activities in canopy- and understory humus of two montane forest types in Ailao Mountains, Northwest China].

    Science.gov (United States)

    Liu, Yong-jie; Liu, Wen-yao; Chen, Lin; Zhang, Han-bo; Wang, Gao-sheng

    2010-09-01

    Mid-montane moist evergreen broadleaved forest (MMF) and top-montane dwarf mossy forest (DMF) are the two major natural forest types in subtropical mountainous area of Ailao Mountains, Northwest China. In this paper, a comparative study was made on the microbial composition, quantity, biochemical activity, metabolic activity, and their seasonal dynamics in the canopy- and understory humus of the two forest types. The composition, quantity, and metabolic activity of the microbes in the canopy humus of dominant tree species in MMF and DMF were also analyzed. In the canopy humus of the two forest types, the amounts of fungi and actinomycetes, microbial biomass C and N, and intensities of nitrogen fixation and cellulose decomposition were significantly higher than those in understory humus. Meanwhile, the amount of cellulose-decomposing microbes (ACDM), cellulose decomposition intensity, microbial biomass C and N, and metabolic activity in the canopy humus of MMF were significantly higher than those of DMF. The amounts of bacteria, fungi, and aerobic nitrogen-fixing bacteria (ANFB) and the metabolic activity in the canopy humus of MMF and DMF were significantly higher in wet season than in dry season, while a contradictory trend was observed on the amount of actinomycetes. No significant difference was observed on the amount of ACDM between wet season and dry season. For the two forest types, the amounts of microbes and their biochemical activities in canopy humus had a larger seasonal variation range than those in understory humus. There was a significant difference in the amounts of the microbes in canopy humus among the dominant tree species in MMF and DMF, especially in wet season. The microbes in canopy humus played important roles in maintaining the biodiversity of epiphytes in the canopy, and in supplying the needed nutrients for the vigorous growth of the epiphytes.

  13. Calculation methods of reactivity using derivatives of nuclear power and Filter fir; Metodos para o calculo da reatividade usando derivadas da potencia nuclear e o filtro FIR

    Energy Technology Data Exchange (ETDEWEB)

    Diaz, Daniel Suescun

    2007-07-01

    This work presents two new methods for the solution of the inverse point kinetics equation. The first method is based on the integration by parts of the integral of the inverse point kinetics equation, which results in a power series in terms of the nuclear power in time dependence. Applying some conditions to the nuclear power, the reactivity is represented as first and second derivatives of this nuclear power. This new calculation method for reactivity has special characteristics, amongst which the possibility of using different sampling periods, and the possibility of restarting the calculation, after its interruption associated it with a possible equipment malfunction, allowing the calculation of reactivity in a non-continuous way. Apart from this reactivity can be obtained with or without dependency on the nuclear power memory. The second method is based on the Laplace transform of the point kinetics equations, resulting in an expression equivalent to the inverse kinetics equation as a function of the power history. The reactivity can be written in terms of the summation of convolution with response to impulse, characteristic of a linear system. For its digital form the Z-transform is used, which is the discrete version of the Laplace transform. In this method it can be pointed out that the linear part is equivalent to a filter named Finite Impulse Response (Fir). The Fir filter will always be, stable and non-varying in time, and, apart from this, it can be implemented in the non-recursive way. This type of implementation does not require feedback, allowing the calculation of reactivity in a continuous way. The proposed methods were validated using signals with random noise and showing the relationship between the reactivity difference and the degree of the random noise. (author)

  14. Star Formation Under the Outflow: The Discovery of a Non-thermal Jet from OMC-2 FIR 3 and Its Relationship to the Deeply Embedded FIR 4 Protostar

    Science.gov (United States)

    Osorio, Mayra; Díaz-Rodríguez, Ana K.; Anglada, Guillem; Megeath, S. Thomas; Rodríguez, Luis F.; Tobin, John J.; Stutz, Amelia M.; Furlan, Elise; Fischer, William J.; Manoj, P.; Gómez, José F.; González-García, Beatriz; Stanke, Thomas; Watson, Dan M.; Loinard, Laurent; Vavrek, Roland; Carrasco-González, Carlos

    2017-05-01

    We carried out multiwavelength (0.7-5 cm), multi-epoch (1994-2015) Very Large Array (VLA) observations toward the region enclosing the bright far-IR sources FIR 3 (HOPS 370) and FIR 4 (HOPS 108) in OMC-2. We report the detection of 10 radio sources, 7 of them identified as young stellar objects. We image a well-collimated radio jet with a thermal free-free core (VLA 11) associated with the Class I intermediate-mass protostar HOPS 370. The jet features several knots (VLA 12N, 12C, 12S) of non-thermal radio emission (likely synchrotron from shock-accelerated relativistic electrons) at distances of ˜7500-12,500 au from the protostar, in a region where other shock tracers have been previously identified. These knots are moving away from the HOPS 370 protostar at ˜100 km s-1. The Class 0 protostar HOPS 108, which itself is detected as an independent, kinematically decoupled radio source, falls in the path of these non-thermal radio knots. These results favor the previously proposed scenario in which the formation of HOPS 108 is triggered by the impact of the HOPS 370 outflow with a dense clump. However, HOPS 108 has a large proper motion velocity of ˜30 km s-1, similar to that of other runaway stars in Orion, whose origin would be puzzling within this scenario. Alternatively, an apparent proper motion could result because of changes in the position of the centroid of the source due to blending with nearby extended emission, variations in the source shape, and/or opacity effects.

  15. Diseño de Filtros FIR de Retraso Fraccionario Mediante Optimización en Frecuencia Fractional Delay FIR Filter Design using Frequency-Based Optimization

    Directory of Open Access Journals (Sweden)

    J. Díaz-Carmona

    2005-01-01

    Full Text Available En este artículo se describe el diseño en el dominio de la frecuencia de filtros digitales FIR de retraso fraccionario (Fractional Delay Filter, FDF con características de ancho de banda amplio y una resolución fina de retraso. El método de diseño en frecuencia utilizado está basado en optimización con mínimos cuadrados en la aproximación de series de Taylor de la señal de entrada. La propuesta consiste en reducir la complejidad de la optimización en frecuencia al momento de diseñar el FDF. Lo anterior se logra con la combinación de una estructura multirazón (multirate y una estructura Farrow modificada. El filtro resultante presenta como ventajas un número reducido de operaciones por muestra de salida y una reducción notable en la carga computacional de diseño.A frequency domain design method for fractional delay FIR filters (Fractional Delay Filter, FDF with wide bandwidth and fine delay resolution is described. The frequency domain method is based on a least square Taylor series approximation of the input signal. The proposed design method consists of reducing the complexity of the frequency optimization workload in the design of the FDF. This is obtained by the combination of a multirate structure and a modified Farrow structure. The resulting filter has a reduced number of arithmetic operations per output sample and yields a significant reduction in the design computational workload.

  16. Tree-ring stable isotopes record the impact of a foliar fungal pathogen on CO2 assimilation and growth in Douglas-fir

    Science.gov (United States)

    Swiss needle cast (SNC) is a fungal disease of Douglas-fir (Pseudotsuga menziesii) that has recently become prevalent in coastal areas of the Pacific Northwest. We used growth measurements and stable isotopes of carbon and oxygen in tree-rings of Douglas-fir and a non-susceptible...

  17. Filtered Iterative Reconstruction (FIR) via Proximal Forward-Backward Splitting: A Synergy of Analytical and Iterative Reconstruction Method for CT

    CERN Document Server

    Gao, Hao

    2015-01-01

    This work is to develop a general framework, namely filtered iterative reconstruction (FIR) method, to incorporate analytical reconstruction (AR) method into iterative reconstruction (IR) method, for enhanced CT image quality. Specifically, FIR is formulated as a combination of filtered data fidelity and sparsity regularization, and then solved by proximal forward-backward splitting (PFBS) algorithm. As a result, the image reconstruction decouples data fidelity and image regularization with a two-step iterative scheme, during which an AR-projection step updates the filtered data fidelity term, while a denoising solver updates the sparsity regularization term. During the AR-projection step, the image is projected to the data domain to form the data residual, and then reconstructed by certain AR to a residual image which is in turn weighted together with previous image iterate to form next image iterate. Since the eigenvalues of AR-projection operator are close to the unity, PFBS based FIR has a fast convergenc...

  18. Role of geographical provenance in the response of silver fir seedlings to experimental warming and drought.

    Science.gov (United States)

    Matías, Luis; Gonzalez-Díaz, Patricia; Quero, José L; Camarero, J Julio; Lloret, Francisco; Jump, Alistair S

    2016-10-01

    Changes in climate can alter the distribution and population dynamics of tree species by altering their recruitment patterns, especially at range edges. However, geographical patterns of genetic diversity could buffer the negative consequences of changing climate at rear range edges where populations might also harbour individuals with drought-adapted genotypes. Silver fir (Abies alba Mill.) reaches its south-western distribution limit in the Spanish Pyrenees, where recent climatic dieback events have disproportionately affected westernmost populations. We hypothesized that silver fir populations from the eastern Pyrenees are less vulnerable to the expected changing climate due to the inclusion of drought-resistant genotypes. We performed an experiment under strictly controlled conditions simulating projected warming and drought compared with current conditions and analysed physiology, growth and survival of silver fir seedlings collected from eastern and western Pyrenean populations. Genetic analyses separated eastern and western provenances in two different lineages. Climate treatments affected seedling morphology and survival of both lineages in an overall similar way: elevated drought diminished survival and induced a higher biomass allocation to roots. Increased temperature and drought provoked more negative stem water potentials and increased δ(13)C ratios in leaves. Warming reduced nitrogen concentration and increased soluble sugar content in leaves, whereas drought increased nitrogen concentration. Lineage affected these physiological parameters, with western seedlings being more sensitive to warming and drought increase in terms of δ(13)C, nitrogen and content of soluble sugars. Our results demonstrate that, in A. alba, differences in the physiological response of this species to drought are also associated with differences in biogeographical history.

  19. Genetic analysis of silver-fir populations in the North Carpathian and Sudeten Mountains

    Directory of Open Access Journals (Sweden)

    Leon Mejnartowicz

    2011-01-01

    Full Text Available Seeds collected from individual trees in the 16 Carpathian and 2 Sudeten silver-fir (Abies alba populations were studied with the starch gel electrophoresis in megagametophytes using 14 enzyme systems with 28 loci. The results show that the geographical distance between populations are in a small part reflected in genetic distances. There are two main groups of populations: Sudeten and Carpathian with a very big genetic distance between them. Other populations consist of a few small groups with low gene flow between them (Nm = 3.286. About 80% of genetic variation is located within populations (FST = 0.223. Average values for genetic multiplicity and diversity for Carpathian populations are as follows: number of alleles per locus: Na = 2.308, with effective number of alleles Ne = 1.552 and proportion of polymorphic loci 71.21%. The mean number of alleles per locus (Na varied from 2.107 to 2.607 in population. The mean effective number of alleles per locus (Ne ranged from 1.429 to 1.662. Average Fis for Carpathian populations was -0.021, which means that there is small excess of heterozygotes. The average observed heterozygosity amounted to Ho = 0.275 and expected heterozygosity was He = 0.269. The dendrogram structure and presence of rare alleles found in silver-fir of Czech, and Slovakian populations allow for a hypothesis that in postglaciation the silver-fir moved into the Polish Carpathians not westward from the east but from the south along river valleys from some Balkan refuges, getting North bypassing the High Tatra Range. This way, a highly diversified set of populations originated, differ in the presence of rare alleles. This differentiation is not prevented by a relatively small flow of genes between populations. The calculated gene flow Nm = 3.286 also indicates isolation between the populations. It means 3.3 immigrants per generation into the studied populations.

  20. Effects of an Experimental Drought on Balsam Fir Xylogenesis in the Eastern Canada Boreal Forest.

    Science.gov (United States)

    D'Orangeville, L.; Côté, B.; Houle, D.; Morin, H.

    2014-12-01

    A 20-40% reduction in soil moisture is projected for the boreal forest of Eastern Canada for the period 2070-99 relative to 1971-2000. In order to better predict the effects of a reduced water supply on the growth of balsam fir (Abies balsamea (L.) Mill.), a dominant tree species of the boreal forest, we simulated 2 consecutive years of summer droughts (starting in July) by means of throughfall exclusion. Four 100-m2 plots were established in 2010 with polyethylene sheets maintained 1.3-2 m aboveground and redirecting the water outside the plots. Wood microcores were extracted weekly from mature trees from April to October 2011 to analyse the time dynamics of wood formation in that year. The number of tracheids formed during and before treatment and their anatomical characteristics were determined through microscopic analyses. The growth of lateral and terminal branches and the water potential of balsam fir seedlings were also monitored. Throughfall exclusion significantly reduced soil water content by 5.8% in 2010 and 10.5% in 2011. Xylogenesis was affected significantly by the treatment. Tracheids were 16.1% smaller in diameter and their cell wall was 14.1% thicker during both years. The treatment delayed by more than a week the start of the tracheid differentiation process in the second year with a concomitant decrease (26%) in the number of tracheids produced. The seedlings displayed a 32% reduction in growth and a 40% reduction in leaf water potential. Our results suggest that a future regime of increased frequency and intensity of droughts could have nega­tive effects on the duration of xylogenesis and the amount of carbon sequestrated in balsam fir.

  1. An Experimental Assessment of Transverse Adaptive Fir Filters as Applied to Vibrating Structures Identification

    Directory of Open Access Journals (Sweden)

    Daniel A. Castello

    2005-01-01

    Full Text Available The present work is aimed at assessing the performance of adaptive Finite Impulse Response (FIR filters on the identification of vibrating structures. Four adaptive algorithms were used: Least Mean Squares (LMS, Normalized Least Mean Squares (NLMS, Transform-Domain Least Mean Squares (TD – LMS and Set-Membership Binormalized Data-Reusing LMS Algorithm (SM – BNDRLMS. The capability of these filters to perform the identification of vibrating structures is shown on real experiments. The first experiment consists of an aluminum cantilever beam containing piezoelectric sensors and actuators and the second one is a steel pinned-pinned beam instrumented with accelerometers and an electromechanical shaker.

  2. Gyrotrons for High-Power Terahertz Science and Technology at FIR UF

    CERN Document Server

    Idehara, Toshitaka

    2016-01-01

    In this paper, we present the recent progress in the development of a series of gyrotrons at FIR UF that have opened the road to many novel applications in the high-power Terahertz science and technology. The current status of the research in this actively developing field is illustrated by the most representative examples in which the developed gyrotrons are used as powerful and frequency tunable sources of coherent radiation operating in a CW regime. Among them are high-precision spectroscopic techniques (most notably DNP-NMR, ESR, XDMR, and studies of the hyperfine splitting of the energy levels of positronium), treatment and characterization of advanced materials, new medical technologies.

  3. Modified Particle Swarm Optimization for Blind Deconvolution and Identification of Multichannel FIR Filters

    Directory of Open Access Journals (Sweden)

    Khanagha Ali

    2010-01-01

    Full Text Available Blind identification of MIMO FIR systems has widely received attentions in various fields of wireless data communications. Here, we use Particle Swarm Optimization (PSO as the update mechanism of the well-known inverse filtering approach and we show its good performance compared to original method. Specially, the proposed method is shown to be more robust against lower SNR scenarios or in cases with smaller lengths of available data records. Also, a modified version of PSO is presented which further improves the robustness and preciseness of PSO algorithm. However the most important promise of the modified version is its drastically faster convergence compared to standard implementation of PSO.

  4. A low-power asynchronous data-path for a FIR filter bank

    DEFF Research Database (Denmark)

    Nielsen, Lars Skovby; Sparsø, Jens

    1996-01-01

    This paper describes a number of design issues relating to the implementation of low-power asynchronous signal processing circuits. Specifically, the paper addresses the design of a dedicated processor structure that implements an audio FIR filter bank which is part of an industrial application. ...... the implications it has on the choice of architecture, handshake-protocol, data-encoding, and circuit design. This includes a tagging scheme that divides the data-path into slices, and an asynchronous ripple carry adder that avoids a completion tree....

  5. A Low Power Linear Phase Digital FIR Filter for Wearable ECG Devices.

    Science.gov (United States)

    Lian, Yong; Yu, Jianghong

    2005-01-01

    In this paper we present a low power linear phase digital FIR filter which is a part of an ECG-on-Chip. The ECG-on-Chip can be embedded into clothing to acquire the electrocardiogram (ECG) signal and send a warning message to a mobile phone or PDA if an abnormal ECG is detected. The proposed new filter structure significantly reduces the arithmetic operations for each sample which in turn lowers the power consumption. The filter is developed based on the interpolated finite impulse filter technique and is very attractive for a low cost and low power VLSI implementation.

  6. Lnear Phase FIR Filter on Measuring 3—D Surface

    Institute of Scientific and Technical Information of China (English)

    WANGYunshan; YANGFujun; 等

    1997-01-01

    An optical technology for 3-D surface measurement is se up.The technology,based on a deformed projected grating pattern which carries the 3-D information of the measured object,can automatically and accurately obtain the phase map of a measured object by using a linear-phase FIR filter.In contrast to the 2-D fast Fourier transform technique,it's more than fast.Only one image pattern is sufficient for measuring .The phase map can be processed without assigning fringe orders and making distinction between a depression and an elevation.Theoretical analysis and experimental result are presented.

  7. Herschel/HIFI spectroscopy of the intermediate mass protostar NGC 7129 FIRS 2

    DEFF Research Database (Denmark)

    Johnstone, D.; Fich, M.; McCoey, C.

    2010-01-01

    Herschel/HIFI observations of water from the intermediate mass protostar NGC 7129 FIRS 2 provide a powerful diagnostic of the physical conditions in this star formation environment. Six spectral settings, covering four H216O and two H218O lines, were observed and all but one H218O line were...... are consistent with emission from water arising in the envelope around the intermediate mass protostar, and the abundance of H2O is constrained to ˜10-7 for the outer envelope. Additionally, the presence of a narrow self-absorption component for the lowest energy lines is likely due to self-absorption from...

  8. Density Fluctuation Measurements Using FIR Interferometer on HL-2A Tokamak

    Institute of Scientific and Technical Information of China (English)

    ZHOU Yan; PENG Bei-Bin; YANG Qing-wei; DUAN Xu-Ru; DING Xuan-Tong; LI Lian-Cai; LI Yong-Gao; JIAO Yi-Ming; DENG Zhong-Chao; YI Jiang; LIU Yi; ZHAO Kai-Jun; JI Xiao-Quan

    2008-01-01

    Denity fluctuations were first measured in the core region of HL-2A tokamak plasma using a newly developed multi-channel FIR interferometer system. In divertor ohmic discharges, we measured the radial density fluctuation levels of 5%, which increase to 10-20% during the appearance of MHD activity. Most of the power density in the density fluctuation spectrum is directly associated with m=2 tearing modes. The fluctuation levels reduce to 1/3 and plasma confinement is improved during off-axis electron-cyclotron-resonance heating (ECRH).Supported by the National Natural Science Foundation of China under Grant Nos 10575030 and 10675043.

  9. Design of broadly tuned FIR FEL based on a variable-period microwiggler

    Energy Technology Data Exchange (ETDEWEB)

    Qing-Xiang Liu [Institute of Applied Electronics, Sichuan (China)]|[Southwest Jiaotong Univ., Sichuan (China); Yong Xu [Southwest Jiatong Univ., Sichuan (China)

    1995-12-31

    A varible-period microwiggler is proposed and investigated. The fundamental period of the microwiggler is designed as {lambda}o=2mm, and the period of the microwiggler can be turned from {lambda}o to n{lambda}o (n=1,2,3,{hor_ellipsis}) The wiggler fields with the period 3{lambda}o, 4{lambda}o, and 5{lambda}o are measured and compared with the theoretical results. Finally, a broadly tuned FIR FEL is designed based on the performance of the variable-period microwiggler.

  10. Transpiration Regulation of silver firs during and after severe droughts in relation to soil properties

    Science.gov (United States)

    Chanzy, A.; Nourtier, M.

    2011-12-01

    Silver fir is declining and dying in the Mediterranean area, at its southern margin where climate is expected to become warmer and drier. At regional scale, silver fir death seems to be located on dry areas while it depends on soil water availability at forest stand scale. To understand silver firs vulnerability to drought, factors involved in their transpiration regulation were studied. An experiment was carried out on Mont Ventoux (in Provence region in south of France) which is a karstic area. Soil properties were characterised by electric resistivity tomography for estimating soil water storage capacity through the determination of soil depth and stones content. Transpiration, predawn leaf water potential dynamic and crown surface temperature were measured on trees during three years. Vulnerability curves to embolism of coarse roots and branches were established. Finally, tree growth rate history was analysed using tree ring width analysis. The experiment covered three very different climatic years. 2008 was a wet year, whereas a severe drought occurred in summer 2009 and in less extent in 2010. Soils were well watered during winters thanks to exceptional snow falls. In the context of the experiment, silver firs strongly regulate their transpiration. Transpiration/potential transpiration ratio is mostly far below 1. The decrease in transpiration rate during drying periods were the quickest on soil having small and large water storage capacity whereas on the intermediate cases, the decrease was more gradual. Moreover, the water stress intensity, derived from predawn leaf water potential, was the largest on soil having large water storage capacity. After the 2009 severe drought, transpiration rate remains much low after fall rainfalls. The transpiration drop persisted after the winter while soils were well watered. Sap flow radial distributions have suggested that the deeps roots were not reactivated after the drought. Tring ring width analysis showed that the

  11. Spectral-line Survey at Millimeter and Submillimeter Wavelengths toward an Outflow-shocked Region, OMC 2-FIR 4

    Science.gov (United States)

    Shimajiri, Yoshito; Sakai, Takeshi; Kitamura, Yoshimi; Tsukagoshi, Takashi; Saito, Masao; Nakamura, Fumitaka; Momose, Munetake; Takakuwa, Shigehisa; Yamaguchi, Takahiro; Sakai, Nami; Yamamoto, Satoshi; Kawabe, Ryohei

    2015-12-01

    We performed the first spectral line survey at 82-106 GHz and 335-355 GHz toward the outflow-shocked region OMC 2-FIR 4, the outflow driving source FIR 3, and the northern outflow lobe FIR 3N. We detected 120 lines of 20 molecular species. The line profiles can be classified into two types: one type is a single Gaussian component with a narrow (3 km s-1) widths. The narrow components for most of the lines are detected at all positions, suggesting that they trace the ambient dense gas. For CO, CS, HCN, and HCO+, the wide components are detected at all positions, suggesting an outflow origin. The wide components of C34S, SO, SiO, H13CN, HC15N, {{{H}}}213CO, H2CS, HC3N, and CH3OH are only detected at FIR 4, suggesting an origin as outflow-shocked gas. The rotation diagram analysis revealed that the narrow components of C2H and H13CO+ show low temperatures of 12.5 ± 1.4 K, while the wide components show high temperatures of 20-70 K. This supports our interpretation that the wide components trace the outflow and/or outflow-shocked gas. We compared the observed molecular abundances relative to H13CO+ with those of the outflow-shocked region L 1157 B1 and the hot corino IRAS 16293-2422. Although we cannot exclude the possibility that the chemical enrichment in FIR 4 is caused by hot-core chemistry, the chemical compositions in FIR 4 are more similar to those in L 1157 B1 than those in IRAS 16293-2422.

  12. Comparative study on active soil organic matter in Chinese fir plantation and native broad-leaved forest in subtropical China

    Institute of Scientific and Technical Information of China (English)

    WANG Qing-kui; WANG Si-long; DENG Shi-jian

    2005-01-01

    Active soil organic matter (ASOM) has a main effect on biochemical cycles of soil nutrient elements such as N, P and S, and the quality and quantity of ASOM reflect soil primary productivity. The changes of ASOM fractions and soil nutrients in the first rotation site and the second rotation site of Chinese fir plantation and the native broad-leaved forest were investigated and analyzed by soil sampling at the Huitong Experimental Station of Forestry Ecology (at latitude 26°48′N and longitude 109°30′E under a subtropical climate conditions), Chinese Academy of Sciences in March, 2004. The results showed that values of ASOM fractions for the Chinese fir plantations were lower than those for the broad-leaved forest. The contents of easily oxidisable carbon (EOC), microbial biomass carbon (MBC), water soluble carbohydrate (WSC) and water-soluble organic carbon (WSOC) for the first rotation of Chinese fir plantation were 35.9%, 13.7%, 87.8% and 50.9% higher than those for the second rotation of Chinese fir plantation, and were 15.8%, 47.3%, 38.1% and 30.2% separately lower than those for the broad-leaved forest. For the three investigated forest sites, the contents of MBC and WSOC had a larger decrease, followed by WSC, and the change of EOC was least. Moreover, soil physico-chemistry properties such as soil nutrients in Chinese fir plantation were lower than those in broad-leaved forest. It suggested that soil fertility declined after Chinese fir plantation replaced native broad-leaved forest through continuous artificial plantation.

  13. [Identification and analysis of differentially expressed genes during wood formation in Chinese fir by SSH].

    Science.gov (United States)

    Wang, Gui-Feng; Gao, Yan; Yang, Li-Wei; Shi, Ji-Sen

    2007-04-01

    Wood is an important raw material for the global industry with rapidly increasing demand. To isolate the differentially expressed genes in xylogenesis of Chinese fir [Cunninghamia lanceolata (Lamb.) Hook], a forward subtractive cDNA library was constructed using suppression subtractive hybridization (SSH) method, which was performed using the cDNA from the mutant Dugansha clone as the tester and the cDNA from the normal Jurong 0 clone as the driver. Six hundred and eighteen clones were obtained. Recombinants were identified using PCR with universal T7 and SP6 primers and using EcoR digestion. To further eliminate false positive, dot hybridization was used with four DIG-labeled probes (FSP, RSP, UTP, and UDP). Real-time PCR was performed to confirm the results. A total of 260 unique ESTs were obtained, 60% of the ESTs exhibiting homologies with proteins of known function fell into 4 major classes: metabolism, cell wall biogenesis and remodeling, signal transduction and stress. The systematic analysis of genes involved in wood formation in Chinese fir provides valuable insights into the molecular mechanisms involved in xylem differentiation, is important resources for forest research directed toward understanding the genetic control of wood formation and future endeavors to modify wood and fiber properties for industrial use.

  14. Tolerance to multiple climate stressors: A case study of Douglas-fir drought and cold hardiness

    Science.gov (United States)

    Bansal, Sheel; Harrington, Constance A; St. Clair, John Bradley

    2016-01-01

    Summary: 1. Drought and freeze events are two of the most common forms of climate extremes which result in tree damage or death, and the frequency and intensity of both stressors may increase with climate change. Few studies have examined natural covariation in stress tolerance traits to cope with multiple stressors among wild plant populations. 2. We assessed the capacity of coastal Douglas-fir (Pseudotsuga menziesii var. menziesii), an ecologically and economically important species in the northwestern USA, to tolerate both drought and cold stress on 35 populations grown in common gardens. We used principal components analysis to combine drought and cold hardiness trait data into generalized stress hardiness traits to model geographic variation in hardiness as a function of climate across the Douglas-fir range. 3. Drought and cold hardiness converged among populations along winter temperature gradients and diverged along summer precipitation gradients. Populations originating in regions with cold winters had relatively high tolerance to both drought and cold stress, which is likely due to overlapping adaptations for coping with winter desiccation. Populations from regions with dry summers had increased drought hardiness but reduced cold hardiness, suggesting a trade-off in tolerance mechanisms. 4. Our findings highlight the necessity to look beyond bivariate trait–climate relationships and instead consider multiple traits and climate variables to effectively model and manage for the impacts of climate change on widespread species.

  15. Investigation of process of interception in beech-fir stand on mountain Goch

    Directory of Open Access Journals (Sweden)

    Ristić Ratko

    2002-01-01

    Full Text Available Part of the precipitation is intercepted by vegetation before reaching the ground. The portion of intercepted water, which is retained in storage of the vegetal cover and evaporates, is called the interception loss. Interception represents important component of water balance, because of reduction of total rainfall. It decreases potential for forming of surface runoff. Depends on complex of vegetative and climate factors. In humid forested regions about 25% of the annual precipitation may become interception loss. Results of investigation in beech-fir stand on mountain Goch are presented in this paper Investigation was carried out on experimental catchment area Vaona IV (A=0.098 km2, in association Abieti-fagetum, on mountain Goch, in Central Serbia. Standard rain gauges were used to determine total precipitation and throughfalls, during vegetation period (1992-1997. Total interception (Ic depends on total precipitation (Pb, kind of trees, shape and density of the crown, position in the stand and age. Average values of interception (Icsr during vegetation period (1992-1997, amount to Icsr=43.7-53.3% of total precipitation (fir, and Icsr=17.7-22.8% (beech.

  16. On the nature of the deeply embedded protostar OMC-2 FIR 4

    CERN Document Server

    Furlan, E; Osorio, M; Stutz, A M; Fischer, W J; Ali, B; Stanke, T; Manoj, P; Adams, J D; Tobin, J J

    2014-01-01

    We use mid-infrared to submillimeter data from the Spitzer, Herschel, and APEX telescopes to study the bright sub-mm source OMC-2 FIR 4. We find a point source at 8, 24, and 70 $\\mu$m, and a compact, but extended source at 160, 350, and 870 $\\mu$m. The peak of the emission from 8 to 70 $\\mu$m, attributed to the protostar associated with FIR 4, is displaced relative to the peak of the extended emission; the latter represents the large molecular core the protostar is embedded within. We determine that the protostar has a bolometric luminosity of 37 Lsun, although including more extended emission surrounding the point source raises this value to 86 Lsun. Radiative transfer models of the protostellar system fit the observed SED well and yield a total luminosity of most likely less than 100 Lsun. Our models suggest that the bolometric luminosity of the protostar could be just 12-14 Lsun, while the luminosity of the colder (~ 20 K) extended core could be around 100 Lsun, with a mass of about 27 Msun. Our derived lu...

  17. Drying characteristics and equilibrium moisture content of steam-treated Douglas fir (Pseudotsuga menziesii L.).

    Science.gov (United States)

    Lam, Pak Sui; Sokhansanj, Shahab; Bi, Xiaotao T; Lim, C Jim; Larsson, Sylvia H

    2012-07-01

    Douglas fir (Pseudotsuga menziesii L.) particles were exposed to high pressure saturated steam (200 and 220 °C for 5 and 10 min) to improve the durability and hydrophobicity of pellets produced from them. Depending on treatment severity, the moisture content of the particles increased from 10% to 36% (wet basis). Douglas fir particles steam-treated at 220 °C for 10 min had the fastest drying rate of 0.014 min(-1). The equilibrium moisture content (EMC) of steam-treated samples decreased with increasing steam temperature and treatment time. The Giggnheim-Anderson-deBoer (GAB) equilibrium model gave a good fit with the equilibrium data with R(2) = 0.99. The adsorption rate of untreated pellets exposed to humid air (30 °C, 90% RH) for 72 h was 0.0152 min(-1) while that of steam-treated pellets ranged from 0.0125 to 0.0135 min(-1) without a clear trend with steam treatment severity. These findings are critical to develop durable and less hygroscopic pellets.

  18. Soil carbon budget in different-aged Chinese fir plantations in south China

    Institute of Scientific and Technical Information of China (English)

    Shebao Yu; Dan Wang; Wei Dai; Ping Li

    2014-01-01

    Understanding the age effect on soil carbon balance in forest ecosystems is important for other material cycles and forest man-agement. In this research we investigated soil organic carbon density, litter production, litter decomposition rate, soil respiration, and soil mi-crobial properties in a chronosequence of four Chinese fir plantations of 7, 16, 23 and 29 years at Dagangshan mountain range, Jiangxi Province, south China. There was a significant increasing trend in litter production with increasing plantation age. Litter decomposition rate and soil respira-tion, however, declined from the 7-year to the 16-year plantation, and then increased after 16 years. This was largely dependent on soil micro-organisms. Soil carbon output was higher than carbon input before 16 years, and total soil carbon stock declined from 35.98 t·ha-1 in the 7-year plantation to 30.12 t·ha-1 in the 16-year plantation. Greater litter produc-tion could not explain the greater soil carbon stock, suggesting that forest growth impacted this microbial process that controlled rates of soil car-bon balance together with litter and soil respiration. The results highlight the importance of the development stage in assessing soil carbon budget and its significance to future management of Chinese fir plantations.

  19. Low temperature FIR and submm mass absorption coefficient of interstellar silicate dust analogues

    CERN Document Server

    Coupeaud, A; Meny, C; Nayral, C; Delpech, F; Leroux, H; Depecker, C; Creff, G; Brubach, J B; Roy, P

    2011-01-01

    Cold dust grains emission in the FIR/submm is usually expressed as a modified black body law in which the dust mass absorption coefficient (MAC), is described with a temperature- and wavelength-independent emissivity spectral index, beta. However, numerous data from space and balloon-born missions and recently from Herschel and Planck show that dust emission is not well understood, as revealed by the observed anti-correlation of beta with the grain temperature. In order to give astronomers the necessary data to interpret FIR/submm observations, we synthesised analogues of interstellar amorphous and crystalline silicate grains, rich in Mg and Ca, and having stiochiometry of olivine and pyroxene and measured their MAC, in the 100-1000/1500 \\mum range for grain temperatures varying from 300 to 10 K. We find that the grain MAC decreases when the grain temperature decreases and that the local spectral index, beta, defined as the slope of the MAC curve, is anti-correlated with the grain temperature. These variation...

  20. Evaluation of the FIR Example using Xilinx Vivado High-Level Synthesis Compiler

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Zheming [Argonne National Lab. (ANL), Argonne, IL (United States); Finkel, Hal [Argonne National Lab. (ANL), Argonne, IL (United States); Yoshii, Kazutomo [Argonne National Lab. (ANL), Argonne, IL (United States); Cappello, Franck [Argonne National Lab. (ANL), Argonne, IL (United States)

    2017-07-28

    Compared to central processing units (CPUs) and graphics processing units (GPUs), field programmable gate arrays (FPGAs) have major advantages in reconfigurability and performance achieved per watt. This development flow has been augmented with high-level synthesis (HLS) flow that can convert programs written in a high-level programming language to Hardware Description Language (HDL). Using high-level programming languages such as C, C++, and OpenCL for FPGA-based development could allow software developers, who have little FPGA knowledge, to take advantage of the FPGA-based application acceleration. This improves developer productivity and makes the FPGA-based acceleration accessible to hardware and software developers. Xilinx Vivado HLS compiler is a high-level synthesis tool that enables C, C++ and System C specification to be directly targeted into Xilinx FPGAs without the need to create RTL manually. The white paper [1] published recently by Xilinx uses a finite impulse response (FIR) example to demonstrate the variable-precision features in the Vivado HLS compiler and the resource and power benefits of converting floating point to fixed point for a design. To get a better understanding of variable-precision features in terms of resource usage and performance, this report presents the experimental results of evaluating the FIR example using Vivado HLS 2017.1 and a Kintex Ultrascale FPGA. In addition, we evaluated the half-precision floating-point data type against the double-precision and single-precision data type and present the detailed results.

  1. Role of canopy interception on water and nutrient cycling in Chinese fir plantation ecosystem

    Institute of Scientific and Technical Information of China (English)

    KANG Wenxing; DENG Xiangwen; ZHAO Zhonghui

    2007-01-01

    The role of canopy interception on nutrient cycling in Chinese fir plantation ecosystem was studied on the basis of the position data during four years.Results indicate that the average canopy interception amount was 267.0 mm/year.Canopy interception play a significant role in water cycle and nutrient cycle processes in ecosystem,and was an important part of evaporation from the Chinese fir plantation ecosystem,being up to 27.2%.The evaporation from the canopy interception was an important way of water output from ecosystem,up to 19.9%.The flush-eluviation of branches and leaves caused by canopy interception brought nutrient input of 143.629 kg/(hm2·year),which was 117.2% of the input 63.924kg/(hm2·year)from the atmospheric precipitation.The decreased amount of 80.1 mm precipitation input caused by canopy interception reduced the amount of rainfall into the stand surface and infiltration into the soil,reduced the output with runoff and drainage,and decreased nutrient loss through output water.Therefore,the additional preserve of nutrient by canopy interception was 8.664 kg/(hm2·year).

  2. 1-D Systolic Arrays Design of LMS Adaptive (FIR Digital Filtering

    Directory of Open Access Journals (Sweden)

    Ali H. Mahdi

    2010-01-01

    Full Text Available This paper extends the 1-D systolic array approach with a method of systematic linear design of systolic algorithms. Past methods for mapping the Least-Mean-Square (LMS Adaptive Finite-Impulse-Response (FIR filter onto parallel and pipelined architectures either introduce delays in the coefficients updates or have excessive hardware requirements. In this article, we describe an efficient 1-D systolic array for the LMS adaptive FIR filter that produces the same output and error signals as produced by the standard LMS adaptive filter architecture with single assignment form of processor functions.The proposed systolic architectures that are designed operate on a block-by-block basis and makes use of the flexibility in the design, which takes the inner product step (convolution sum of the tap weight vector and the tap input vector in the design consideration. It enables us to extract more than one algorithm for the same problem. The input and output data flow sequentially and continuously into and out of the systolic arrays at the system clock rates, during each clock period, processing element of the same type operates in parallel. The most computationally demanding among them performs only two consecutive multiplications and two additions/subtractions per clock period, thereby allowing a very high throughput and very fast block signal processing to be achieved at the expense of a delay of L samples between the input and output and 100% utilization, L being the block size.

  3. FIR Spectroscopy of the Galactic Center: Hot and Warm Molecular Gas

    CERN Document Server

    Goicoechea, J R; Cernicharo, J; Gerin, M; Pety, J

    2016-01-01

    The angular resolution (~10") achieved by the Herschel Space Observatory ~3.5m telescope at FIR wavelengths allowed us to roughly separate the emission toward the inner parsec of the galaxy (the central cavity) from that of the surrounding circumnuclear disk (the CND). The FIR spectrum toward SgrA* is dominated by intense [Oiii], [Oi], [Cii], [Niii], [Nii], and [Ci] fine-structure lines (in decreasing order of luminosity) arising in gas irradiated by the strong UV field from the central stellar cluster. The high-J CO rotational line intensities observed at the interface between the inner CND and the central cavity are consistent with a hot isothermal component at T~10^{3.1} K and n(H_2)~10^4 cm^{-3}. They are also consistent with a distribution of lower temperatures at higher gas density, with most CO at T~300 K. The hot CO component (either the bulk of the CO column density or just a small fraction depending on the above scenario) likely results from a combination of UV and shock-driven heating. Although thi...

  4. HERSCHEL-HIFI spectroscopy of the intermediate mass protostar NGC7129 FIRS 2

    CERN Document Server

    Johnstone, D; McCoey, C; van Kempen, T A; Fuente, A; Kristensen, L E; Cernicharo, J; Caselli, P; Visser, R; Plume, R; Herczeg, G J; van Dishoeck, E F; Wampfler, S; Bachiller, R; Baudry, A; Benedettini, M; Bergin, E; Benz, A O; Bjerkeli, P; Blake, G; Bontemps, S; Braine, J; Bruderer, S; Codella, C; Daniel, F; di Giorgio, A M; Dominik, C; Doty, S D; Encrenaz, P; Giannini, T; Goicoechea, J R; de Graauw, Th; Helmich, F; Herpin, F; Hogerheijde, M R; Jacq, T; Jørgensen, J K; Larsson, B; Lis, D; Liseau, R; Marseille, M; Melnick, G; Neufeld, D; Nisini, B; Olberg, M; Parise, B; Pearson, J; Risacher, C; Santiago-García, J; Saraceno, P; Shipman, R; Tafalla, M; van der Tak, F; Wyrowski, F; Yıldız, U A; Caux, E; Honingh, N; Jellema, W; Schieder, R; Teyssier, D; Whyborn, N

    2010-01-01

    HERSCHEL-HIFI observations of water from the intermediate mass protostar NGC7129 FIRS 2 provide a powerful diagnostic of the physical conditions in this star formation environment. Six spectral settings, covering four H216O and two H218O lines, were observed and all but one H218O line were detected. The four H2 16 O lines discussed here share a similar morphology: a narrower, \\approx 6 km/s, component centered slightly redward of the systemic velocity of NGC7129 FIRS 2 and a much broader, \\approx 25 km/s component centered blueward and likely associated with powerful outflows. The narrower components are consistent with emission from water arising in the envelope around the intermediate mass protostar, and the abundance of H2O is constrained to \\approx 10-7 for the outer envelope. Additionally, the presence of a narrow self-absorption component for the lowest energy lines is likely due to self-absorption from colder water in the outer envelope. The broader component, where the H2O/CO relative abundance is fou...

  5. Chemical composition of decomposing stumps in successive rotation of Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) plantations

    Institute of Scientific and Technical Information of China (English)

    HUANG Zhiqun; XU Zhihong; BOYD Sue; WILLIAMS David

    2005-01-01

    Decomposition of stumps in successive rotation of Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) plantations was studied using a chronosequence approach. The results showed that decomposition rate constant of Chinese fir stump was 0.02695 as calculated from Olson's model. The N content of stump increased during the first two-year decomposition. When the dead stump C/N ratio was 463.2 ± 27.3, the stumps started to release N. The pattern of P release was similar to that for N. However, K content of stumps showed a consistent declining trend over time during the whole decomposition. 13C nuclear magnetic resonance spectroscopy with cross polarization and magic-angle spinning (13C CPMAS-NMR) was used to analyse organic carbon (C) components in decomposing stumps. The 13C CPMAS-NMR spectra of stumps displayed that stump was dominated by cellulose and hemicellulose. The spectra also showed the accumulation of intensity in alkyl C, aromatic C, and carboxyl C spectral regions, which was expected as the labile cellulose and hemicellulose components in O-alkyl C spectral region were selectively decomposed first.

  6. Low frequency radio-FIR correlation in normal galaxies at ~1 kpc scales

    CERN Document Server

    Basu, Aritra; Mitra, Dipanjan

    2012-01-01

    We study the radio--FIR correlation between the nonthermal (synchrotron) radio continuum emission at \\lambda 90 cm (333 MHz) and the far infrared emission due to cool (~20 K) dust at \\lambda 70\\mu m in spatially resolved normal galaxies at scales of ~1 kpc. The slope of the radio--FIR correlation significantly differs between the arm and interarm regions. However, this change is not evident at a lower wavelength of \\lambda 20 cm (1.4 GHz). We find the slope of the correlation in the arm to be 0.8 \\pm 0.12 and we use this to determine the coupling between equipartition magnetic field (B_{eq}) and gas density (\\rho_{gas}) as B_{eq} \\propto \\rho_{gas}^{0.51 \\pm 0.12}. This is close to what is predicted by MHD simulations of turbulent ISM, provided the same region produces both the radio and far infrared emission. We argue that at 1 kpc scales this condition is satisfied for radio emission at 1.4 GHz and may not be satisfied at 333 MHz. Change of slope observed in the interarm region could be caused by propagatio...

  7. LOW-FREQUENCY RADIO-FIR CORRELATION IN NORMAL GALAXIES AT {approx}1 kpc SCALES

    Energy Technology Data Exchange (ETDEWEB)

    Basu, Aritra; Roy, Subhashis; Mitra, Dipanjan, E-mail: aritra@ncra.tifr.res.in, E-mail: roy@ncra.tifr.res.in, E-mail: dmitra@ncra.tifr.res.in [National Center for Radio Astrophysics, TIFR, Pune University Campus, Ganeshkhind Road, Pune-411007 (India)

    2012-09-10

    We study the radio-FIR correlation between the nonthermal (synchrotron) radio continuum emission at {lambda}90 cm (333 MHz) and the far-infrared emission due to cool ({approx}20 K) dust at {lambda}70 {mu}m in spatially resolved normal galaxies at scales of {approx}1 kpc. The slope of the radio-FIR correlation significantly differs between the arm and interarm regions. However, this change is not evident at a lower wavelength of {lambda}20 cm (1.4 GHz). We find the slope of the correlation in the arm to be 0.8 {+-} 0.12 and we use this to determine the coupling between equipartition magnetic field (B{sub eq}) and gas density ({rho}{sub gas}) as B{sub eq}{proportional_to}{rho}{sup 0.51{+-}0.12}{sub gas}. This is close to what is predicted by magnetohydrodynamic simulations of turbulent interstellar medium, provided the same region produces both the radio and far-infrared emission. We argue that at 1 kpc scales this condition is satisfied for radio emission at 1.4 GHz and may not be satisfied at 333 MHz. The change of slope observed in the interarm region could be caused by propagation of low energy ({approx}1.5 GeV) and long-lived ({approx}10{sup 8} yr) cosmic-ray electrons at 333 MHz.

  8. A Method for Designing FIR Filters with Arbitrary Magnitude Characteristic Used for Modeling Human Audiogram

    Directory of Open Access Journals (Sweden)

    SZOPOS, E.

    2012-05-01

    Full Text Available This paper presents an iterative method for designing FIR filters that implement arbitrary magnitude characteristics, defined by the user through a set of frequency-magnitude points (frequency samples. The proposed method is based on the non-uniform frequency sampling algorithm. For each iteration a new set of frequency samples is generated, by processing the set used in the previous run; this implies changing the samples location around the previous frequency values and adjusting their magnitude through interpolation. If necessary, additional samples can be introduced, as well. After each iteration the magnitude characteristic of the resulting filter is determined by using the non-uniform DFT and compared with the required one; if the errors are larger than the acceptable levels (set by the user a new iteration is run; the length of the resulting filter and the values of its coefficients are also taken into consideration when deciding a re-run. To demonstrate the efficiency of the proposed method a tool for designing FIR filters that match human audiograms was implemented in LabVIEW. It was shown that the resulting filters have smaller coefficients than the standard one, and can also have lower order, while the errors remain relatively small.

  9. Investigation of bunch repetition rate deviations in FIR FEL driven by a magnetron-based microtron

    CERN Document Server

    Kazakevitch, Grigori M; Lee Byung Cheol; Lee, J

    2002-01-01

    The stability of the bunch repetition rate in a FIR FEL driven by a 2.8 GHz magnetron-based microtron was investigated using a heterodyne method with a low Q-factor straight-flight measuring cavity. The measuring cavity is located in the straight section of the FIR FEL injection beam line and is excited by the passage of electron bunches. The RF signal from the measuring cavity coupling loop was mixed with a precise heterodyne signal with a frequency difference of several MHz. The beat frequency was analyzed to obtain the temporal distribution of the bunch repetition rate deviation during the macro pulse of the electron beam. The time resolution and the accuracy of measurements are approximately 100 ns and a few kHz, respectively. Based on this data, we could determine the level and shape of the magnetron current and the initial frequency shift between magnetron and accelerating cavity for the FEL operation in the wavelength range 100-300 microns.

  10. Photosynthetic temperature responses of tree species in Rwanda: evidence of pronounced negative effects of high temperature in montane rainforest climax species

    Science.gov (United States)

    Vårhammar, Angelica; Wallin, Göran; McLean, Christopher M.; Dusenge, Mirindi Eric; Medlyn, Belinda E.; Hasper, Thomas B.; Nsabimana, Donat; Uddling, Johan

    2015-04-01

    The sensitivity of photosynthetic metabolism to temperature has been identified as a key uncertainty for projecting the magnitude of the terrestrial feedback on future climate change. While temperature responses of photosynthetic capacities have been comparatively well investigated in temperate species, the responses of tropical tree species remain unexplored. We compared the responses of seedlings of native cold-adapted tropical montane rainforest tree species to exotic warm-adapted plantation species, all growing in an intermediate temperature common garden in Rwanda. Leaf gas exchange responses to CO2 at different temperatures (20 - 40 C) were used to assess the temperature responses of biochemical photosynthetic capacities. Analyses revealed a lower optimum temperature for photosynthetic electron transport rates than for Rubisco carboxylation rates, along with lower electron transport optima in the native cold-adapted than in the exotic warm-adapted species. The photosynthetic optimum temperatures were generally exceeded by daytime peak leaf temperatures, in particular in the native montane rainforest climax species. This study thus provides evidence of pronounced negative effects of high temperature in tropical trees and indicates high susceptibility of montane rainforest climax species to future global warming. (Reference: New Phytologist, in press)

  11. Ectomycorrhizal fungi associated with ponderosa pine and Douglas-fir: a comparison of species richness in native western North American forests and Patagonian plantations from Argentina.

    Science.gov (United States)

    Barroetaveña, C; Cázares, E; Rajchenberg, M

    2007-07-01

    The putative ectomycorrhizal fungal species registered from sporocarps associated with ponderosa pine and Douglas-fir forests in their natural range distribution (i.e., western Canada, USA, and Mexico) and from plantations in south Argentina and other parts of the world are listed. One hundred and fifty seven taxa are reported for native ponderosa pine forests and 514 taxa for native Douglas-fir forests based on available literature and databases. A small group of genera comprises a high proportion of the species richness for native Douglas-fir (i.e., Cortinarius, Inocybe, and Russula), whereas in native ponderosa pine, the species richness is more evenly distributed among several genera. The comparison between ectomycorrhizal species richness associated with both trees in native forests and in Patagonia (Argentina) shows far fewer species in the latter, with 18 taxa for the ponderosa pine and 15 for the Douglas-fir. Epigeous species richness is clearly dominant in native Douglas-fir, whereas a more balanced relation epigeous/hypogeous richness is observed for native ponderosa pine; a similar trend was observed for Patagonian plantations. Most fungi in Patagonian Douglas-fir plantations have not been recorded in plantations elsewhere, except Suillus lakei and Thelephora terrestris, and only 56% of the fungal taxa recorded in Douglas-fir plantations around the world are known from native forests, the other taxa being new associations for this host, suggesting that new tree + ectomycorrhizal fungal taxa associations are favored in artificial situations as plantations.

  12. Tree-ring stable isotopes record the impact of a foliar fungal pathogen on CO(2) assimilation and growth in Douglas-fir.

    Science.gov (United States)

    Saffell, Brandy J; Meinzer, Frederick C; Voelker, Steven L; Shaw, David C; Brooks, J Renée; Lachenbruch, Barbara; McKay, Jennifer

    2014-07-01

    Swiss needle cast (SNC) is a fungal disease of Douglas-fir (Pseudotsuga menziesii) that has recently become prevalent in coastal areas of the Pacific Northwest. We used growth measurements and stable isotopes of carbon and oxygen in tree-rings of Douglas-fir and a non-susceptible reference species (western hemlock, Tsuga heterophylla) to evaluate their use as proxies for variation in past SNC infection, particularly in relation to potential explanatory climate factors. We sampled trees from an Oregon site where a fungicide trial took place from 1996 to 2000, which enabled the comparison of stable isotope values between trees with and without disease. Carbon stable isotope discrimination (Δ(13)C) of treated Douglas-fir tree-rings was greater than that of untreated Douglas-fir tree-rings during the fungicide treatment period. Both annual growth and tree-ring Δ(13)C increased with treatment such that treated Douglas-fir had values similar to co-occurring western hemlock during the treatment period. There was no difference in the tree-ring oxygen stable isotope ratio between treated and untreated Douglas-fir. Tree-ring Δ(13)C of diseased Douglas-fir was negatively correlated with relative humidity during the two previous summers, consistent with increased leaf colonization by SNC under high humidity conditions that leads to greater disease severity in following years.

  13. Influence of a sand soil plough base on the growth of Douglas fir (Pseudotsuga menziesii (MIRB.) FRANCO).

    NARCIS (Netherlands)

    Gruber, F; Nick, L

    2000-01-01

    The root/shoot growth of eight year old Douglas fir trees (Pseudotsuga menziesii (MIRB.) FRANCO) planted on ploughed agricultured land in the first generation was investigated. One half of the field was 60 cm deeply ploughed before afforestation. The second half was not deeply ploughed and was compa

  14. Spectral-Line Survey at Millimeter and Submillimeter Wavelengths toward an Outflow-Shocked Region, OMC 2-FIR 4

    CERN Document Server

    Shimajiri, Yoshito; Kitamura, Yoshimi; Tsukagoshi, Takashi; Saito, Masao; Nakamura, Fumitaka; Momose, Munetake; Takakuwa, Shigehisa; Yamaguchi, Takahiro; Sakai, Nami; Yamamoto, Satoshi; Kawabe, Ryohei

    2015-01-01

    We performed the first spectral-line survey at 82--106 GHz and 335--355 GHz toward the outflow-shocked region, OMC 2-FIR 4, the outflow driving source, FIR 3, and the northern outflow lobe, FIR 3N. We detected 120 lines of 20 molecular species. The line profiles are found to be classifiable into two types: one is a single Gaussian component with a narrow ($$ 3km s$^{-1}$) widths. The narrow components for the most of the lines are detected at all positions, suggesting that they trace the ambient dense gas. For CO, CS, HCN, and HCO$^{+}$, the wide components are detected at all positions, suggesting the outflow origin. The wide components of C$^{34}$S, SO, SiO, H$^{13}$CN, HC$^{15}$N, H$_2^{13}$CO, H$_2$CS, HC$_3$N, and CH$_3$OH are detected only at FIR 4, suggesting the outflow-shocked gas origin. The rotation diagram analysis revealed that the narrow components of C$_2$H and H$^{13}$CO$^+$ show low temperatures of 12.5$\\pm$1.4 K, while the wide components show high temperatures of 20--70 K. This supports our...

  15. Assessing intra- and inter-regional climate effects on Douglas-fir biomass dynamics in Oregon and Washington, USA

    Science.gov (United States)

    David M. Bell; Andrew N. Gray

    2016-01-01

    While ecological succession shapes contemporary forest structure and dynamics, other factors like forest structure (dense vs. sparse canopies) and climate may alter structural trajectories. To assess potential sources of variation in structural trajectories, we examined proportional biomass change for a regionally dominant tree species, Douglas-fir (...

  16. A strategy for monitoring Swiss needle cast and assessing its growth impact in Douglas-fir plantations of Coastal Oregon

    Science.gov (United States)

    Doug Maguire; Alan Kanaskie; Mike McWilliams

    2000-01-01

    Many Douglas-fir plantations along the north coast of Oregon are exhibiting severe symptoms of Swiss needle cast disease (SNC). These symptoms include premature loss of foliage, abundant fungal pseudothecia on needles, yellowing of foliage, and apparent reduction in diameter and height growth. The development of the disease and its impacts on growth are currently being...

  17. Fingerprints of a forest fungus: Swiss needle cast, carbon isotopes, carbohydrates, and growth in Douglas-fir

    Science.gov (United States)

    Andrea Watts; Frederick Meinzer; Brandy J. Saffell

    2014-01-01

    Swiss needle cast is caused by a fungus native to the Pacific Northwest. Its host is Douglas-fir, an iconic evergreen tree in the region. The fungus does not kill its host, but it adversely affects the tree's growth. The fungal fruiting bodies block the stomata, small openings on the underside of the needle where carbon dioxide, water vapor, and other gases are...

  18. Performance and Complexity Analysis of Blind FIR Channel Identification Algorithms Based on Deterministic Maximum Likelihood in SIMO Systems

    DEFF Research Database (Denmark)

    De Carvalho, Elisabeth; Omar, Samir; Slock, Dirk

    2013-01-01

    We analyze two algorithms that have been introduced previously for Deterministic Maximum Likelihood (DML) blind estimation of multiple FIR channels. The first one is a modification of the Iterative Quadratic ML (IQML) algorithm. IQML gives biased estimates of the channel and performs poorly at lo...

  19. Slow and fast pyrolysis of Douglas-fir lignin: Importance of liquid-intermediate formation on the distribution of products

    NARCIS (Netherlands)

    Zhou, Shuai; Pecha, Brennan; Kuppevelt, van Michiel; McDonald, Armando G.; Garcia-Perez, Manuel

    2014-01-01

    The formation of liquid intermediates and the distribution of products were studied under slow and fast pyrolysis conditions. Results indicate that monomers are formed from lignin oligomeric products during secondary reactions, rather than directly from the native lignin. Lignin from Douglas-fir (Ps

  20. Age-class differences in shoot photosynthesis and water relations of Fraser fir (Abies fraseri), southern Appalachian Mountains, USA

    Science.gov (United States)

    Keith Reinhardt; Daniel M. Johnson; William K. Smith

    2009-01-01

    Fraser fir (Abies fraseri (Pursh) Poir.) is an endemic tree species found only in refugial mountain-top forests in the southern Appalachian Mountains, USA. Very few studies have investigated the ecophysiology of this species in its natural environment. We measured and compared photosynthetic gas exchange and water relations of understory germinant...

  1. Fire-mediated pathways of stand development in Douglas-fir/western hemlock forests of the Pacific Northwest, USA

    Science.gov (United States)

    A.J. Tepley; F.J. Swanson; T.A. Spies

    2013-01-01

    Forests dominated by Douglas-fir and western hemlock in the Pacific Northwest of the United States have strongly influenced concepts and policy concerning old-growth forest conservation. Despite the attention to their old-growth characteristics, a tendency remains to view their disturbance ecology in relatively simple terms, emphasizing infrequent, stand-replacing (SR...

  2. The importance of seasonal temperature and moisture patterns on growth of Douglas-fir in western Oregon, USA

    Science.gov (United States)

    Douglas-fir growth in the Pacific Northwest is thought to be water limited. However, discerning the relative influence of air temperature and plant available soil water (W) on growth is difficult because they interact with each other, with other climate factors and with the inher...

  3. Simulating historical disturbance regimes and stand structures in old-forest ponderosa pine/Douglas-fir forests

    Science.gov (United States)

    Mike Hillis; Vick Applegate; Steve Slaughter; Michael G. Harrington; Helen Smith

    2001-01-01

    Forest Service land managers, with the collaborative assistance from research, applied a disturbance based restoration strategy to rehabilitate a greatly-altered, high risk Northern Rocky Mountain old-forest ponderosa pine-Douglas-fir stand. Age-class structure and fire history for the site have been documented in two research papers (Arno and others 1995, 1997)....

  4. Influence of a sand soil plough base on the growth of Douglas fir (Pseudotsuga menziesii (MIRB.) FRANCO).

    NARCIS (Netherlands)

    Gruber, F; Nick, L

    The root/shoot growth of eight year old Douglas fir trees (Pseudotsuga menziesii (MIRB.) FRANCO) planted on ploughed agricultured land in the first generation was investigated. One half of the field was 60 cm deeply ploughed before afforestation. The second half was not deeply ploughed and was

  5. Impacts of cloud immersion on microclimate, photosynthesis and water relations of fraser fir in a temperate mountain cloud forest

    Science.gov (United States)

    Keith Reinhardt; William K. Smith

    2010-01-01

    The red spruce-Fraser fir ecosystem (Picea rubens Sarg.-Abies fraseri [Pursh] Poir.) of the southern Appalachian mountains is a temperate zone cloud forest immersed in clouds for 30 to 40 percent of a typical summer day, and experiencing immersion on about 65 percent of all days annually. We compared the microclimate,...

  6. Effects of site management treatments on growth of six-year-old, second-rotation Chinese fir (Cunninghamia lanceolata) plantations

    Institute of Scientific and Technical Information of China (English)

    HE Zongming; FAN Shaohui; LU Jingming; YANG Xujing; WENG Xianquan

    2007-01-01

    The effects of five different site management treatments on the productivity of a six-year-old and secondrotation Chinese fir(Cunninghamia lanceolata(Lamb.)Hook.)plantations planted after harvesting a 29-year-old and first-rotation Chinese fir plantation in Xiayang State Forest Farm,Nanping,Fujian Province,were studied.Results showed that the Chinese fir grew best on plots treated with the double slash treatment(BL3),followed by the whole tree harvest(BL1)and the slash burning treatment(SB),and poorest on treatment BL2(normal slash retention)and BL0 (removal of all organic matter aboveground).The site index of the second rotation Chinese fir plantations in BL3 and BL0 treatments increased by 0.56 and 0.27,respectively,compared with the first rotation,and decreased in the rest of the three treatments.Compared with the first rotation,the site index of the second rotation treated with BL1,SB and BL2 treatments decreased by 0.39,0.45 and 0.63,respectively.Differences among the treatments were not statistically significant.

  7. Comparison of Dilute Acid and Sulfite Pretreatment for enzymatic Saccharification of Earlywood and Latewood of Douglas Fir

    Science.gov (United States)

    Chao Zhang; Xiaochun Lei; C. Tim Scott; J.Y. Zhu; Kecheng Li

    2014-01-01

    This study applied dilute acid (DA) and sulfite pretreatment to overcome the recalcitrance of lignocelluloses (SPORL) to deconstruct earlywood and latewood cell walls of Douglas fir for fermentable sugars production through subsequent enzymatic hydrolysis. DA pretreatment removed almost all the hemicelluloses, while SPORL at initial pH=4.5 (SP-B) removed significant...

  8. Effect of organic amendments on Douglas-fir transplants grown in fumigated versus non-fumigated soil

    Science.gov (United States)

    Nabil Khudduri

    2010-01-01

    We transplanted one-year old Douglas-fir (Pseudotsuga menziesii var. menziesii) seedlings into compost-amended soil that had either been spring-fumigated with a methyl bromide/chloropicrin combination or left unfumigated. Seedling nutrient, pathology, morphology, and packout measurements were significantly better for those transplanted into fumigated rather than non-...

  9. Short-day treatment alters Douglas-fir seedling dehardening and transplant root proliferation at varying rhizosphere temperatures

    Science.gov (United States)

    Douglass F. Jacobs; Anthony S. Davis; BArrett C. Wilson; R. Kasten Dumroese; Rosa C. Goodman; K. Francis Salifu

    2008-01-01

    We tested effects of shortened day length during nursery culture on Douglis-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco) seedling development at dormancy release. Seedlings from a 42 N source were grown either under ambient photoperiods (long-day (LD)) or with a 28 day period of 9 h light: 15 h dark photoperiods (short...

  10. Business Ethics in Third World Countries. A Romanian Representative Case: Roşia Montană

    Directory of Open Access Journals (Sweden)

    Iuliana Zaharia

    2010-03-01

    Full Text Available

    Roşia Montană case became representative by its complexity, considering the interaction of the economic with other social sectors on one hand, and on the other hand, considering the context of a economy on the globalization edge in a South-eastern European country 'rebuilt' after 1989 and in a permanent 'reform' of 20 years, representative by the way the economics dictates to the politics, sealing the road to sustainable disaster in an "era of sustainable development”. Edifying symbol of the times that we live at the beginning of the XXIst century, maintaing the focus on the Romanian opened wound Roşia Montană is equivalent to a live lesson about the survival or the collapse of the (human ecosystem. About the morality as a reality of another order than that of biological life and as a sine qua non condition of the humanity preservation.

    Note: The aggregate term Third World was challenged as misleading starting with the Cold War period, because it got various meanings depending on different points of view: 1. it was used to define during the Cold War the countries that remained non-aligned or not moving at all with either capitalism and NATO (which along with its allies represented the First World or communism and the Soviet Union (which along with its allies represented the Second World; 2. it has also a completely different definition according to human development index – the term Third World, when used today generally denotes countries that have not "developed" to the same levels as OECD countries, and which are thus in the process of "developing"; 3. in the 1980s, economist Peter Bauer offered a competing definition for the term Third World, claiming that the attachment of Third World status to a particular country was not based on any stable economic or political criteria, and was a mostly arbitrary process. The large diversity of countries that were considered to be part of the Third World, from Indonesia to Afghanistan

  11. Element export from a small catchment in the tropical montane forest of Ecuador responds to climate change

    Science.gov (United States)

    Leimer, Sophia; Willimann, Elias; Alaoui, Abdallah; Trachte, Katja; Wilcke, Wolfgang

    2015-04-01

    In a very remote tropical montane rain forest in the Ecuadorian Andes on the rim of the Amazon basin, increasing temperatures, longer dry spells, and an associated reduction in soil moisture were observed in the past 15 years. In the study ecosystem, element exports from a 9-ha large catchment with stream water are linked to the depth of water flow through soil because of vertical variations in soil chemical properties. The further increase in temperature and precipitation, as predicted by climate models, will have an impact on the water flow paths in soil and therefore alter element exports. Hence, we investigated how future element exports from this catchment in Ecuador will develop under the emission scenarios A1B and B1 for the decades 2050-2059 and 2090-2099 compared to current element exports. Discharge from the study catchment was measured in 1998-2013, partly in high resolution. Element concentrations in stream water (total organic carbon, NO3-N, NH4-N, dissolved organic nitrogen, PO4-P, total dissolved phosphorus, S, Cl, K, Ca, Mg, Na, Zn, Al, Mn) were measured in 1998-2012 in weekly resolution. Based on catchment properties, measured climate, and water flow data, discharge in 1998-2013 was simulated in daily resolution with the hydrological model WaSiM. From the hydrograph of surface flow, three flow classes (baseflow, intermediate, storm) were separated and linked with stream chemical properties. Element concentrations in stream water were grouped according to the flow classes and mean concentrations per flow class were calculated. Subsequently, the mean element concentration was multiplied with the mean of the annual discharge sums per flow class resulting in current element exports. For estimations of future element exports with stream water, discharge was simulated under the emission scenarios A1B and B1 for the decades 2050-2059 and 2090-2099 and separated into the three flow classes. Future element exports per scenario were calculated according to

  12. Variation in leaf litter production and resorption of nutrients in abundant tree species in Nyungwe tropical montane rainforest in Rwanda

    Science.gov (United States)

    Nyirambangutse, Brigitte; Mirindi Dusenge, Eric; Nsabimana, Donat; Bizuru, Elias; Pleijel, Håkan; Uddling, Johan; Wallin, Göran

    2014-05-01

    African tropical rainforests play many roles from local to global scale as providers of resources and ecosystem services. Although covering 30% of the global rainforest, only few studies aiming to better understand the storage and fluxes of carbon and nutrients in these forests have been conducted. To answer questions related to these issues, we have established 15 permanent 0.5 ha plots where we compare carbon and nutrient fluxes of primary and secondary forest tree communities in a tropical montane forest in central Africa. The studies are conducted in Nyungwe montane tropical rain forest gazetted as a National Park to protect its extensive floral and faunal diversity covering an area of 970 km2. Nyungwe is located in Southwest Rwanda (2o17'-2o50'S, 29o07'-29o26A'E). The forest is ranging between 1600-2950 m.a.s.l. and is one of the most biologically important rainforest in Albertine Rift region in terms of Biodiversity. Nyungwe consists of a mixture of primary and secondary forest communities supporting a richness of plant and animal life. More than 260 species of trees and shrubs have been found in Nyungwe, including species endemic to the Albertine Rift. The forest has a climate with a mean annual temperature of 15.5oC and annual rainfall of ca 1850 mm yr-1, with July and August being the only months when rainfall drops. A part of this study is focusing on the dynamics of nutrients through leaf turnover. This turnover of leaves is regulated to maximize the carbon gain through canopy photosynthesis and resource-use efficiency of the plant. It is known that about half of leaf nitrogen is invested in photosynthetic apparatus and that there normally is a strong correlation between the photosynthetic capacity and leaf nitrogen per unit area. Hence leaf nitrogen is an important factor for canopy photosynthesis. However, leaves are produced, senesce and fall. Some nitrogen in the leaf is lost when leaves senesce but other is resorbed. The resorption of nitrogen

  13. The Seasonal and Diurnal Patterns of net Ecosystem CO2 Exchange in a Subtropical Montane Cloud Forest.

    Science.gov (United States)

    Chu, H.; Lai, C.; Wu, C.; Hsia, Y.

    2008-12-01

    CO2 fluxes were measured by an open/closed path eddy covariance system at a natural regenerated 50-years-old yellow cypress (Chamaecyparis obtusa var. formosana) forest at Chi-Lan Mountain site (CLM site, 24°35'N, 121°25'E, 1650 m elevation), north-eastern Taiwan. CLM site is located at a relative uniform south-eastern-facing valley slope (15°) characterized with year round fog occurrence and diurnal mountain-valley wind and can be classified as subtropical montane cloud forest. Based on measurement from July 2007 to June 2008, seasonal and diurnal patterns of CO2 fluxes were described and patterns under different cloudiness and foggy conditions were presented. Comparing with other cypress forests in temperate region, there is only a weak seasonal pattern of the CO2 fluxes at CLM site. Throughout the year, average incident photosynthetically active radiation in summer was almost the double of that in winter, whereas the difference of mean daytime CO2 fluxes among seasons was much less than the seasonal light difference. During summer when light intensity was higher, mean daytime CO2 fluxes reached -7.5 μmol/m2/s in July and -8.8 μmol/m2/s in August. As heavy fog accounted for 64% and 67% of the time in November and February, mean daytime CO2 fluxes dropped to -6.9 and -6.1 μmol/m2/s respectively. With comparable higher incident radiation intensity (>1000 μmol/m2/s), the CO2 fluxes were higher in overcast days than in clear days. In July 2007, clear days accounted for 30% of the month, light intensity reached its peak at midday, and however, CO2 fluxes didn't reach its highest value in the meanwhile. Canopy conductance calculated from the Penman-Monteith equation and measured latent heat fluxes both showed a midday depression at clear days, which indicated the regulation of transpiration by plant physiological mechanism. With comparable lower incident radiation intensity (<1000 μmol/m2/s), the CO2 fluxes were higher in overcast days than in foggy days. The

  14. Lithology rules badland distribution and typology in a montane Mediterranean environment (upper Llobregat basin, Catalan Pre-Pyrenees)

    Science.gov (United States)

    Moreno de las Heras, Mariano; Gallart, Francesc

    2016-04-01

    Badlands (i.e. highly dissected areas carved in soft bedrock with little or no vegetation) are pervasive in a wide range of environmental conditions across the Mediterranean region, including semiarid, sub-humid and humid environments, and represent hotspots of erosion and sediment production at the regional scale. On montane (cold sub-humid and humid) Mediterranean landscapes, harsh thermal conditions on north-facing slopes favors intense bedrock weathering and impose serious constraints for plant colonization, which has generally been argued to explain preferential distribution of badlands on shady aspects. We study the distribution and typology of badlands in the upper Llobregat basin (500 km2, 700-2400 m.a.s.l. elevation, 700-900 mm annual rainfall, 8-11°C mean temp.). We mapped regional badlands by manually digitizing affected areas on recent (2012) high resolution (50 cm pixel) ortophotos. Badlands extend over about 200 ha in the upper Llobregat basin and are developed on Paleocene continental lutites (Garumnian Facies, Tremp Formation) and Eocene marine marls (Sagnari, Armancies and Vallfogona Formations). While badlands on Eocene marls showed a preferential distribution on north-facing shady slopes, badland occurrence on the highly unstable smectite-rich Garumnian lutites did not reveal clear aspect trends. In addition, elevation, which broadly controls winter temperatures in the region, did not show a clear influence on badland distribution. A principal component analysis was applied to study badland type using general geomorphological and vegetation metrics (i.e. badland size, slope, aspect, elevation gradient, connection to the regional drainage network, vegetation greenness) derived from a high resolution digital elevation model (5 m pixel) and pan-sharpened Landsat 8 MSAVI imagery (15 m pixel). Lithology was found to largely impact badland type, with Garumnian lutite badlands showing lower slope gradients (20°-30° average slope) than badlands on

  15. Business Ethics in Third World Countries. A Romanian Representative Case: Roşia Montană

    Directory of Open Access Journals (Sweden)

    Iuliana Zaharia

    2010-03-01

    Full Text Available Roşia Montană case became representative by its complexity, considering the interaction of the economic with other social sectors on one hand, and on the other hand, considering the context of a economy on the globalization edge in a South-eastern European country 'rebuilt' after 1989 and in a permanent 'reform' of 20 years, representative by the way the economics dictates to the politics, sealing the road to sustainable disaster in an "era of sustainable development”. Edifying symbol of the times that we live at the beginning of the XXIst century, maintaing the focus on the Romanian opened wound Roşia Montană is equivalent to a live lesson about the survival or the collapse of the (human ecosystem. About the morality as a reality of another order than that of biological life and as a sine qua non condition of the humanity preservation.Note: The aggregate term Third World was challenged as misleading starting with the Cold War period, because it got various meanings depending on different points of view: 1. it was used to define during the Cold War the countries that remained non-aligned or not moving at all with either capitalism and NATO (which along with its allies represented the First World or communism and the Soviet Union (which along with its allies represented the Second World; 2. it has also a completely different definition according to human development index – the term Third World, when used today generally denotes countries that have not "developed" to the same levels as OECD countries, and which are thus in the process of "developing"; 3. in the 1980s, economist Peter Bauer offered a competing definition for the term Third World, claiming that the attachment of Third World status to a particular country was not based on any stable economic or political criteria, and was a mostly arbitrary process. The large diversity of countries that were considered to be part of the Third World, from Indonesia to Afghanistan, ranged

  16. MODELING THE ANOMALY OF SURFACE NUMBER DENSITIES OF GALAXIES ON THE GALACTIC EXTINCTION MAP DUE TO THEIR FIR EMISSION CONTAMINATION

    Energy Technology Data Exchange (ETDEWEB)

    Kashiwagi, Toshiya; Suto, Yasushi; Taruya, Atsushi; Yahata, Kazuhiro [Department of Physics, The University of Tokyo, Tokyo 113-0033 (Japan); Kayo, Issha [Department of Physics, Toho University, Funabashi, Chiba 274-8510 (Japan); Nishimichi, Takahiro, E-mail: kashiwagi@utap.phys.s.u-tokyo.ac.jp [Institute for the Physics and Mathematics of the Universe, University of Tokyo, Kashiwa, Chiba 277-8568 (Japan)

    2015-02-01

    The most widely used Galactic extinction map is constructed assuming that the observed far-infrared (FIR) fluxes come entirely from Galactic dust. According to the earlier suggestion by Yahata et al., we consider how FIR emission of galaxies affects the SFD map. We first compute the surface number density of Sloan Digital Sky Survey (SDSS) DR7 galaxies as a function of the r-band extinction, A {sub r,} {sub SFD}. We confirm that the surface densities of those galaxies positively correlate with A {sub r,} {sub SFD} for A {sub r,} {sub SFD} < 0.1, as first discovered by Yahata et al. for SDSS DR4 galaxies. Next we construct an analytical model to compute the surface density of galaxies, taking into account the contamination of their FIR emission. We adopt a log-normal probability distribution for the ratio of 100 μm and r-band luminosities of each galaxy, y ≡ (νL){sub 100} {sub μm}/(νL) {sub r}. Then we search for the mean and rms values of y that fit the observed anomaly, using the analytical model. The required values to reproduce the anomaly are roughly consistent with those measured from the stacking analysis of SDSS galaxies. Due to the limitation of our statistical modeling, we are not yet able to remove the FIR contamination of galaxies from the extinction map. Nevertheless, the agreement with the model prediction suggests that the FIR emission of galaxies is mainly responsible for the observed anomaly. Whereas the corresponding systematic error in the Galactic extinction map is 0.1-1 mmag, it is directly correlated with galaxy clustering and thus needs to be carefully examined in precision cosmology.

  17. Studies on Electrolyte Conductivity and Activity of Dehydrogenase of Chinese Fir and Masson Pine Bare-Root Seedling under Water and Cold Stress

    Institute of Scientific and Technical Information of China (English)

    Yu Fangyuan; Xu Xizeng; Guo Xinbao

    2003-01-01

    The electrolyte conductivity and activity of dehydrogenase of bare-root seedlings of both Chinese fir (Cunningha-mia lanceolata (Lamb.) Hook.) and Masson pine (Pinus massoniana Lamb.) under freezing and desiccation treatments were studied.The results showed that needle electrolyte conductivity of both species increase significantly after freezing treatment and there are nosignificant differences in needle electrolyte conductivity between the two species. The dehydrogenase activity (ARD) of fine roots ofboth Chinese fir and Masson pine was negatively correlated with increasing freezing and desiccation. The results suggest that bothelectrolyte conductivity and dehydrogenase activity could be used as quick indicators of Chinese fir and Masson pine bare-root seed-ling quality.

  18. Height-Diameter Models for Mixed-Species Forests Consisting of Spruce, Fir, and Beech

    Directory of Open Access Journals (Sweden)

    Petráš Rudolf

    2014-06-01

    Full Text Available Height-diameter models define the general relationship between the tree height and diameter at each growth stage of the forest stand. This paper presents generalized height-diameter models for mixed-species forest stands consisting of Norway spruce (Picea abies Karst., Silver fir (Abies alba L., and European beech (Fagus sylvatica L. from Slovakia. The models were derived using two growth functions from the exponential family: the two-parameter Michailoff and three-parameter Korf functions. Generalized height-diameter functions must normally be constrained to pass through the mean stand diameter and height, and then the final growth model has only one or two parameters to be estimated. These “free” parameters are then expressed over the quadratic mean diameter, height and stand age and the final mathematical form of the model is obtained. The study material included 50 long-term experimental plots located in the Western Carpathians. The plots were established 40-50 years ago and have been repeatedly measured at 5 to 10-year intervals. The dataset includes 7,950 height measurements of spruce, 21,661 of fir and 5,794 of beech. As many as 9 regression models were derived for each species. Although the “goodness of fit” of all models showed that they were generally well suited for the data, the best results were obtained for silver fir. The coefficient of determination ranged from 0.946 to 0.948, RMSE (m was in the interval 1.94-1.97 and the bias (m was -0.031 to 0.063. Although slightly imprecise parameter estimation was established for spruce, the estimations of the regression parameters obtained for beech were quite less precise. The coefficient of determination for beech was 0.854-0.860, RMSE (m 2.67-2.72, and the bias (m ranged from -0.144 to -0.056. The majority of models using Korf’s formula produced slightly better estimations than Michailoff’s, and it proved immaterial which estimated parameter was fixed and which parameters

  19. Sustainable utilization and conservation of plant biodiversity in montane ecosystems: the western Himalayas as a case study

    Science.gov (United States)

    Khan, Shujaul Mulk; Page, Sue E.; Ahmad, Habib; Harper, David M.

    2013-01-01

    Background Conservation of the unique biodiversity of mountain ecosystems needs trans-disciplinary approaches to succeed in a crowded colloquial world. Geographers, conservationists, ecologists and social scientists have, in the past, had the same conservation goals but have tended to work independently. In this review, the need to integrate different conservation criteria and methodologies is discussed. New criteria are offered for prioritizing species and habitats for conservation in montane ecosystems that combine both ecological and social data. Scope Ecological attributes of plant species, analysed through robust community statistical packages, provide unbiased classifications of species assemblages and environmental biodiversity gradients and yield importance value indices (IVIs). Surveys of local communities’ utilization of the vegetation provides use values (UVs). This review suggests a new means of assessing anthropogenic pressure on plant biodiversity at both species and community levels by integrating IVI and UV data sets in a combined analysis. Conclusions Mountain ecosystems are hot spots for plant conservation efforts because they hold a high overall plant diversity as communities replace each other along altitudinal and climatic gradients, including a high proportion of endemic species. This review contributes an enhanced understanding of (1) plant diversity in mountain ecosystems with special reference to the western Himalayas; (2) ethnobotanical and ecosystem service values of mountain vegetation within the context of anthropogenic impacts; and (3) local and regional plant conservation strategies and priorities. PMID:23825353

  20. Two Lactarius species associated with a relict Fagus grandifolia var. mexicana population in a Mexican montane cloud forest.

    Science.gov (United States)

    Montoya, L; Haug, I; Bandala, V M

    2010-01-01

    Ectomycorrhizal (EM) fleshy fungi are being monitored in a population of Fagus grandifolia var. mexicana persisting in a montane cloud forest refuge on a volcano in a subtropical region of central Veracruz (eastern Mexico). The population of Fagus studied represents one of the 10 recognized forest fragments still housing this tree genus in Mexico. This is the first attempt to document EM fungi associated with this tree species in Mexico. We present evidence of the ectomycorrhizal symbiosis for Lactarius badiopallescens and L. cinereus with this endemic tree. Species identification of Lactarius on Fagus grandifolia var. mexicana was based on the comparison of DNAsequences (ITS rDNA) of spatiotemporally co-occurring basidiomes and EM root tips. The host of the EM tips was identified by comparison of the large subunit of the ribulose-bisphosphate carboxylase gene (rbcL). The occurrence of Lactarius badiopallescens and L. cinereus populations in the area of study represent the southernmost record known to date of these two species in North America and are new for the Neotropical Lactarius mycota. Descriptions coupled with illustrations of macro- and micromorphological features of basidiomes as well as photographs of ectomycorrhizas are presented.

  1. Water pollution in gold mining industry: a case study in Roşia Montană district, Romania

    Science.gov (United States)

    Florea, R. M.; Stoica, A. I.; Baiulescu, G. E.; Capotă, P.

    2005-10-01

    The preliminary study of streams and rivers from the Roşia Montană area revealed that the concntration of heavy metals— Cd, Mn, Cu, Pb, and Zn—are above accepted limits. The gold extraction method is based on flotation. The most important pollution sources are mine tailings. The determinations were performed for samples collected in: April 2004, July 2004, September 2004, November 2004, February 2005 and May 2005. The highest concentrations were found for cadmium in September 2004: 0.17 mg/L; for copper in September 2004: 1.38 mg/L; for manganese in July 2004: 239.4 mg/L; for lead in May 2005: 0.54 mg/L; and for zinc in September 2004: 35.37 mg/L;. This study involved three small rivers (streams) that flow into the Mureş River and finally into the Danube River, having a great impact on human health and environmental stability in the area. In May 2005, a sample of drinking water from the mining district was also collected.

  2. Comparative Drought Responses of Quercus ilex L. and Pinus sylvestris L. in a Montane Forest Undergoing a Vegetation Shift

    Directory of Open Access Journals (Sweden)

    David Aguadé

    2015-07-01

    Full Text Available Different functional and structural strategies to cope with water shortage exist both within and across plant communities. The current trend towards increasing drought in many regions could drive some species to their physiological limits of drought tolerance, potentially leading to mortality episodes and vegetation shifts. In this paper, we study the drought responses of Quercus ilex and Pinus sylvestris in a montane Mediterranean forest where the former species is replacing the latter in association with recent episodes of drought-induced mortality. Our aim was to compare the physiological responses to variations in soil water content (SWC and vapor pressure deficit (VPD of the two species when living together in a mixed stand or separately in pure stands, where the canopies of both species are completely exposed to high radiation and VPD. P. sylvestris showed typical isohydric behavior, with greater losses of stomatal conductance with declining SWC and greater reductions of stored non-structural carbohydrates during drought, consistent with carbon starvation being an important factor in the mortality of this species. On the other hand, Q. ilex trees showed a more anisohydric behavior, experiencing more negative water potentials and higher levels of xylem embolism under extreme drought, presumably putting them at higher risk of hydraulic failure. In addition, our results show relatively small changes in the physiological responses of Q. ilex in mixed vs. pure stands, suggesting that the current replacement of P. sylvestris by Q. ilex will continue.

  3. Status and limiting factors of two rare plant species in dry montane communities of Hawai`i Volcanoes National Park.

    Science.gov (United States)

    Pratt, Linda W.; VanDeMark, Joshua R.; Euaparadorn, Melody

    2012-01-01

    Two rare plants native to montane dry forests and woodland communities of Hawai`i Volcanoes National Park (HAVO) were studied for more than two years to determine their stand structure, short-term mortality rates, patterns of reproductive phenology, success of fruit production, floral visitor composition, seed germination rates in the greenhouse, and survival of both natural and planted seedlings. Phyllostegia stachyoides, a shrubby Hawaiian mint (Lamiaceae) that is a species of concern, was studied within two small kīpuka at a natural population on the park’s Mauna Loa Strip, and three plantings at sites along the Mauna Loa Road were also monitored. Silene hawaiiensis, a threatened shrub species in the pink family (Caryophyllaceae), was monitored at two natural populations, one on Mauna Loa at the Three Trees Kīpuka and the second on Kīlauea Crater Rim south of Halema`uma`u. Silene hawaiiensis plantings were also made inside and outside ungulate exclosures at the park’s Kahuku Unit

  4. Linking High Frequency Variations in Stream Water DOC to Ages of Water Sources in Peat-Dominated Montane Watersheds

    Science.gov (United States)

    Tunaley, C.; Tetzlaff, D.; Lessels, J. S.; Soulsby, C.

    2015-12-01

    We combined time series of inferred DOC (from optical sensors) and stable isotopes in streams and watershed source areas to assess the link between water age and C fluxes. We monitored temporal dynamics of FDOM for 2 yrs at nested scales (0.9, 3.0 and 30km2) in a montane Scottish watershed. FDOM was strongly correlated (r2 ~ 0.8) with DOC allowing inference of 15 min timeseries. Marked seasonality was observed, with highest DOC concentrations (~25 mg l-1) in summer events and lower concentrations (~5mg l-1) in winter. During events, anticlockwise hysteresis was observed; consistent with expansion of the riparian saturation zone, increasing hydrological connectivity across peat soils and mobilizing DOC. Lag times for peak discharge and DOC were 1-12 hrs depending on event characteristics and antecedent conditions. Isotope time series from precipitation, streams and catchment source waters (overland flow and hillslope drainage) were also generated. These allowed us to model the non-stationary characteristics of their ages. Stream water age ranges from 3 months at high flows when overland flow dominates runoff to 4 yrs under baseflow. Overland flow age was a dominant influence on DOC transport. Highest concentrations occurred in small summer events with relatively young (strategies.

  5. Flexibility in nest-site choice and nesting success of Turdus rufiventris (Turdidae) in a montane forest in northwestern argentina

    Science.gov (United States)

    Lomascolo, S.B.; Monmany, A.C.; Malizia, A.; Martin, T.E.

    2010-01-01

    We studied the consequences of nest-site choice on nesting success under differing disturbance levels for the Rufous-bellied Thrush (Turdus rufiventris). We compared nest-site choice and nest success between a disturbed site and an undisturbed site in a montane subtropical forest in northwestern Argentina. We found no overall difference in daily predation rate (DPR) between the disturbed and undisturbed sites. However, DPR of nests on bromeliads was significantly lower at the microhabitat level than on other types of subtrates at the disturbed site. T. rufiventris used bromeliads for nesting more often than expected by chance at the disturbed site. DPR did not differ between substrates at the undisturbed site and T. rufiventris used all substrates according to their availability. Nests had higher predation at the disturbed site when DPR on non-bromeliad substrates was compared between disturbed and undisturbed sites. Nest fate was independent of nest height. Our results suggest T. rufiventris' flexibility in nest-site choice, as reflected by increased use of the safest sites, i.e., bromeliads, in the disturbed site compared to the undisturbed site, may allow this species to survive in an otherwise much riskier habitat. Our results illustrate how microhabitat-scale effects can mediate landscape scale effects. ?? 2010 by the Wilson Ornithological Society.

  6. Leaf domatia in montane forest and Caatinga in the semiarid of Pernambuco State: Morphology and ecological implications

    Directory of Open Access Journals (Sweden)

    Taciana Keila dos Anjos Ramalho

    2014-08-01

    Full Text Available Leaf domatia are cavity-shaped structures of different types or tufts of hairs located at the junction between ribs on the abaxial surface of the leaf blades of various families of angiosperms, serving as protection against phytophagous organisms by harboring beneficial mites, suggesting a mutualistic relationship. There is shortage of inventories of species with such structures; thus the present study examined native woody plant in two habitats of the backwoods of Pernambuco to identify the types of leaf domatia. 86 species were observed,43 inCaatinga area, out of which five had domatia, and43 inthe montane forest, 11 species with domatia. Four types of domatia were observed: hairtufts, pocket, pit and revolute margin. There was predominance of plant species with leaf domatia in the area Carro Quebrado in Triunfo,PernambucoState. These results corroborate the information available in the literature in which domatia are prevalent in more humid environments, and that these structures as micro-habitats influence the maintenance of diverse organisms.

  7. A new species of the Rhinella margaritifera species group (Anura, Bufonidae) from the montane forest of the Selva Central, Peru.

    Science.gov (United States)

    Moravec, Jiří; Lehr, Edgar; Cusi, Juan Carlos; Córdova, Jesús H; Gvoždík, Václav

    2014-01-01

    We describe a new species of the bufonid toad genus Rhinella from transition montane forest of the buffer zones of the Yanachaga-Chemillén National Park and the Pui Pui Protected Forest (eastern slopes of Andes, Selva Central, Peru). The new species belongs to the Rhinella margaritifera species group (confirmed by mtDNA data) and differs from all its members by the absence of tympanic membrane and tympanic annulus. It is characterized by medium size (SVL 57.5-65.5 mm, n = 5), moderately developed cranial crests, absence of neural crest of vertebrae, absence of bone protrusion at angle of jaw, presence of lateral rows of enlarged tubercles, and absence of subgular vocal sac and vocal slits in males. In addition, based on the molecular phylogenetic analyses of selected Rhinella species we propose the monophylum containing R. chavin, R. festae, R. macrorhina, R. manu, R. nesiotes, R. rostrata, and R. yanachaga as a new species group under the name Rhinella festae species group.

  8. Microhabitat differences impact phylogeographic concordance of codistributed species: genomic evidence in montane sedges (Carex L.) from the Rocky Mountains.

    Science.gov (United States)

    Massatti, Rob; Knowles, L Lacey

    2014-10-01

    By selecting codistributed, closely related montane sedges from the Rocky Mountains that are similar in virtually all respects but one-their microhabitat affinities-we test predictions about how patterns of genetic variation are expected to differ between Carex nova, an inhabitant of wetlands, and Carex chalciolepis, an inhabitant of drier meadows, slopes, and ridges. Although contemporary populations of the taxa are similarly isolated, the distribution of glacial moraines suggests that their past population connectedness would have differed. Sampling of codistributed population pairs from different mountain ranges combined with the resolution provided by over 24,000 single nucleotide polymorphism loci supports microhabitat-mediated differences in the sedges' patterns of genetic variation that are consistent with their predicted differences in the degree of isolation of ancestral source populations. Our results highlight how microhabitat preferences may interact with glaciations to produce fundamental differences in the past distributions of presently codistributed species. We discuss the implications of these findings for generalizing the impacts of climate-induced distributional shifts for communities, as well as for the prospects of gaining insights about species-specific deterministic processes, not just deterministic community-level responses, from comparative phylogeographic study.

  9. From shifting cultivation to teak plantation: effect on overland flow and sediment yield in a montane tropical catchment.

    Science.gov (United States)

    Ribolzi, Olivier; Evrard, Olivier; Huon, Sylvain; de Rouw, Anneke; Silvera, Norbert; Latsachack, Keo Oudone; Soulileuth, Bounsamai; Lefèvre, Irène; Pierret, Alain; Lacombe, Guillaume; Sengtaheuanghoung, Oloth; Valentin, Christian

    2017-06-21

    Soil erosion supplies large quantities of sediments to rivers of Southeastern Asia. It reduces soil fertility of agro-ecosystems located on hillslopes, and it degrades, downstream, water resource quality and leads to the siltation of reservoirs. An increase in the surface area covered with commercial perennial monocultures such as teak plantations is currently observed at the expanse of traditional slash-and-burn cultivation systems in steep montane environments of these regions. The impacts of land-use change on the hydrological response and sediment yields have been investigated in a representative catchment of Laos monitored for 13 years. After the gradual conversion of rice-based shifting cultivation to teak plantation-based systems, overland flow contribution to stream flow increased from 16 to 31% and sediment yield raised from 98 to 609 Mg km(-2). This result is explained by the higher kinetic energy of raindrops falling from the canopy, the virtual absence of understorey vegetation cover to dissipate drop energy and the formation of an impermeable surface crust accelerating the formation and concentration of overland flow. The 25-to-50% lower (137)Cs activities measured in soils collected under mature teak plantations compared to soils under other land uses illustrate the severity of soil erosion processes occurring in teak plantations.

  10. Seed Dynamics in Relation to Gaps in a Tropical Montane Rainforest of Hainan Island, South China: (Ⅱ) Seed Bank

    Institute of Scientific and Technical Information of China (English)

    Run-Guo Zang; Yi Ding; Wei-Yin Zhang

    2008-01-01

    Spatial and temporal patterns of seed bank dynamics In relation to gaps in an old growth tropical montane rainforast of Hainan Island, South China, were studied over two consecutive years. From June 2001 to June 2003, soil seed bank sampling blocks were taken near each of the four sides of each seed trap and immediately put into a nursery for observation of seedling emergence dynamics in four seasons (each experiment in each season). The abundances of seedlings that emerged from seed banks showed the trend of vine functional group (VFG) > shrub functional group (SFG) > tree functional group (TFG) > herb functional group (HFG), but the trend in species richness of seedlings that emerged from the soil seed banks was TFG > VFG > SFG > HFG. The abundances of seedlings that emerged from seed banks in the three gap zones showed no significant differences, but significant differences did exist for the species richness. The time of sampling or seasons of experiments had significant influences on both the species richness and seedling abundances. The seedling emergence processes of each experiment all revealed the unimodal patterns. Few emergences occurred 1 year after each experiment. Compared with those under closed canopies, the recruitment rates from seed to seedlings and from seedlings to saplings in gaps were higher, but the mortality rates from saplings to big trees were also higher in the gaps.

  11. Negative relationships between cellular immune response, Mhc class II heterozygosity and secondary sexual trait in the montane water vole.

    Science.gov (United States)

    Charbonnel, Nathalie; Bryja, Josef; Galan, Maxime; Deter, Julie; Tollenaere, Charlotte; Chaval, Yannick; Morand, Serge; Cosson, Jean-François

    2010-05-01

    Heterogeneities in immune responsiveness may affect key epidemiological parameters and the dynamics of pathogens. The roles of immunogenetics in these variations remain poorly explored. We analysed the influence of Major histocompatibility complex (Mhc) genes and epigamic traits on the response to phytohaemagglutinin in males from cyclic populations of the montane water vole (Arvicola scherman). Besides, we tested the relevance of lateral scent glands as honest signals of male quality. Our results did not corroborate neither the hypotheses of genome-wide heterozygosity-fitness correlation nor the Mhc heterozygote advantage. We found a negative relationship between Mhc hetetozygosity and response to phytohaemagglutinin, mediated by a specific Mhc homozygous genotype. Our results therefore support the hypothesis of the Arte-Dqa-05 homozygous genotype being a 'good' Mhc variant in terms of immunogenetic quality. The development of the scent glands seems to be an honest signal for mate choice as it is negatively correlated with helminth load. The 'good gene' hypothesis was not validated as Arte-Dqa-05 homozygous males did not exhibit larger glands. Besides, the negative relationship observed between the size of these glands and the response to phytohaemagglutinin, mainly for Mhc homozygotes, corroborates the immunocompetence handicap hypothesis. The Mhc variants associated with larger glands remain yet to be determined.

  12. Mapping the montane cloud forest of Taiwan using 12 year MODIS-derived ground fog frequency data.

    Science.gov (United States)

    Schulz, Hans Martin; Li, Ching-Feng; Thies, Boris; Chang, Shih-Chieh; Bendix, Jörg

    2017-01-01

    Up until now montane cloud forest (MCF) in Taiwan has only been mapped for selected areas of vegetation plots. This paper presents the first comprehensive map of MCF distribution for the entire island. For its creation, a Random Forest model was trained with vegetation plots from the National Vegetation Database of Taiwan that were classified as "MCF" or "non-MCF". This model predicted the distribution of MCF from a raster data set of parameters derived from a digital elevation model (DEM), Landsat channels and texture measures derived from them as well as ground fog frequency data derived from the Moderate Resolution Imaging Spectroradiometer. While the DEM parameters and Landsat data predicted much of the cloud forest's location, local deviations in the altitudinal distribution of MCF linked to the monsoonal influence as well as the Massenerhebung effect (causing MCF in atypically low altitudes) were only captured once fog frequency data was included. Therefore, our study suggests that ground fog data are most useful for accurately mapping MCF.

  13. Habitat moisture is an important driver of patterns of sap flow and water balance in tropical montane cloud forest epiphytes.

    Science.gov (United States)

    Darby, Alexander; Draguljić, Danel; Glunk, Andrew; Gotsch, Sybil G

    2016-10-01

    Microclimate in the tropical montane cloud forest (TMCF) is variable on both spatial and temporal scales and can lead to large fluctuations in both leaf-level transpiration and whole plant water use. While variation in transpiration has been found in TMCFs, the influence of different microclimatic drivers on plant water relations in this ecosystem has been relatively understudied. Within the TMCF, epiphytes may be particularly affected by natural variation in microclimate due to their partial or complete disassociation from soil resources. In this study, we examined the effects of seasonal microclimate on whole plant water balance in epiphytes in both an observational and a manipulative experiment. We also evaluated the effects of different microclimatic drivers using three hierarchical linear (mixed) models. On average, 31 % of total positive sap flow was recovered via foliar water uptake (FWU) over the course of the study. We found that precipitation was the greatest driver of foliar water uptake and nighttime sap flow in our study species and that both VPD and precipitation were important drivers to daytime sap flow. We also found that despite adaptations to withstand seasonal drought, an extended dry period caused severe desiccation in most plants despite a large reduction in leaf-level and whole plant transpiration. Our results indicate that the epiphytes studied rely on FWU to maintain positive water balance in the dry season and that increases in dry periods in the TMCF may be detrimental to these common members of the epiphyte community.

  14. Physiological Responses of Two Epiphytic Bryophytes to Nitrogen, Phosphorus and Sulfur Addition in a Subtropical Montane Cloud Forest

    Science.gov (United States)

    Chen, Xi; Liu, Wen-yao; Song, Liang; Li, Su; Wu, Yi; Shi, Xian-meng; Huang, Jun-biao; Wu, Chuan-sheng

    2016-01-01

    Atmospheric depositions pose significant threats to biodiversity and ecosystem function. However, the underlying physiological mechanisms are not well understood, and few studies have considered the combined effects and interactions of multiple pollutants. This in situ study explored the physiological responses of two epiphytic bryophytes to combined addition of nitrogen, phosphorus and sulfur. We investigated the electrical conductivity (EC), total chlorophyll concentration (Chl), nutrient stoichiometry and chlorophyll fluorescence signals in a subtropical montane cloud forest in south-west China. The results showed that enhanced fertilizer additions imposed detrimental effects on bryophytes, and the combined enrichment of simulated fertilization exerted limited synergistic effects in their natural environments. On the whole, EC, Chl, the effective quantum yield of photosystem II (ΦPSII) and photochemical quenching (qP) were the more reliable indicators of increased artificial fertilization. However, conclusions on nutrient stoichiometry should be drawn cautiously concerning the saturation uptake and nutrient interactions in bryophytes. Finally, we discuss the limitations of prevailing fertilization experiments and emphasize the importance of long-term data available for future investigations. PMID:27560190

  15. Mapping the montane cloud forest of Taiwan using 12 year MODIS-derived ground fog frequency data

    Science.gov (United States)

    Li, Ching-Feng; Thies, Boris; Chang, Shih-Chieh; Bendix, Jörg

    2017-01-01

    Up until now montane cloud forest (MCF) in Taiwan has only been mapped for selected areas of vegetation plots. This paper presents the first comprehensive map of MCF distribution for the entire island. For its creation, a Random Forest model was trained with vegetation plots from the National Vegetation Database of Taiwan that were classified as “MCF” or “non-MCF”. This model predicted the distribution of MCF from a raster data set of parameters derived from a digital elevation model (DEM), Landsat channels and texture measures derived from them as well as ground fog frequency data derived from the Moderate Resolution Imaging Spectroradiometer. While the DEM parameters and Landsat data predicted much of the cloud forest’s location, local deviations in the altitudinal distribution of MCF linked to the monsoonal influence as well as the Massenerhebung effect (causing MCF in atypically low altitudes) were only captured once fog frequency data was included. Therefore, our study suggests that ground fog data are most useful for accurately mapping MCF. PMID:28245279

  16. Design of FIR Filters with Discrete Coefficients using Ant Colony Optimization

    Science.gov (United States)

    Tsutsumi, Shuntaro; Suyama, Kenji

    In this paper, we propose a new design method for linear phase FIR (Finite Impulse Response) filters with discrete coefficients. In a hardware implementation, filter coefficients must be represented as discrete values. The design problem of digital filters with discrete coefficients is formulated as the integer programming problem. Then, an enormous amount of computational time is required to solve the problem in a strict solver. Recently, ACO (Ant Colony Optimization) which is one heuristic approach, is used widely for solving combinational problem like the traveling salesman problem. In our method, we formulate the design problem as the 0-1 integer programming problem and solve it by using the ACO. Several design examples are shown to present effectiveness of the proposed method.

  17. Neural Network Algorithm for Designing FIR Filters Utilizing Frequency-Response Masking Technique

    Institute of Scientific and Technical Information of China (English)

    Xiao-Hua Wang; Yi-Gang He; Tian-Zan Li

    2009-01-01

    This paper presents a new joint optimization method for the design of sharp linear-phase finite-impulse response (FIR) digital filters which are synthesized by using basic and multistage frequency-response-masking (FRM) techniques. The method is based on a batch back-propagation neural network algorithm with a variable learning rate mode. We propose the following two-step optimization technique in order to reduce the complexity. At the first step, an initial FRM filter is designed by alternately optimizing the subfilters. At the second step, this solution is then used as a start-up solution to further optimization. The further optimization problem is highly nonlinear with respect to the coefficients of all the subfilters. Therefore, it is decomposed into several linear neural network optimization problems. Some examples from the literature are given, and the results show that the proposed algorithm can design better FRM filters than several existing methods.

  18. Efficient Algorithms for the Discrete Gabor Transform with a Long Fir Window

    DEFF Research Database (Denmark)

    Søndergaard, Peter Lempel

    2012-01-01

    The Discrete Gabor Transform (DGT) is the most commonly used signal transform for signal analysis and synthesis using a linear frequency scale. The development of the Linear Time-Frequency Analysis Toolbox (LTFAT) has been based on a detailed study of many variants of the relevant algorithms....... As a side result of these systematic developments of the subject, two new methods are presented here. Comparisons are made with respect to the computational complexity, and the running time of optimised implementations in the C programming language. The new algorithms have the lowest known computational...... complexity and running time when a long FIR window is used. The implementations are freely available for download. By summarizing general background information on the state of the art, this article can also be seen as a research survey, sharing with the readers experience in the numerical work in Gabor...

  19. Modeling the hemodynamic response in fMRI using smooth FIR filters

    DEFF Research Database (Denmark)

    Goutte, Cyril; Nielsen, Finn Årup; Hansen, Lars Kai

    2000-01-01

    -parametric approach based on finite impulse response (FIR) filters. In order to cope with the increase in the number of degrees of freedom, the authors introduce a Gaussian process prior on the filter parameters. They show how to carry on the analysis by incorporating prior knowledge on the filters, optimizing hyper......Modeling the hemodynamic response in functional magnetic resonance (fMRI) experiments is an important aspect of the analysis of functional neuroimages. This has been done in the past using parametric response function, from a limited family. In this contribution, the authors adopt a semi......-parameters using the evidence framework, or sampling using a Markov Chain Monte Carlo (MCMC) approach. The authors present a comparison of their model with standard hemodynamic response kernels on simulated data, and perform a full analysis of data acquired during an experiment involving visual stimulation....

  20. Superconductivity in boron carbide? Clarification by low-temperature MIR/FIR spectra.

    Science.gov (United States)

    Werheit, H; Kuhlmann, U

    2011-11-01

    The electronic structure and phonon density of B(13)B(2) boron carbide calculated by Calandra et al (2004 Phys. Rev. B 69 224505) defines this compound as metallic, and the authors predict superconductivity with T(C)s up to 36.7 K. Their results are affected by the same deficiencies as former band structure calculations on boron carbides based on hypothetical crystal structures deviating significantly from the real ones. We present optical mid IR/far IR (MIR/FIR) spectra of boron carbide with compositions between B(4.3)C and B(10.37)C, evidencing semiconducting behaviour at least down to 30 K. There is no indication of superconductivity. The spectra yield new information on numerous localized gap states close to the valence band edge.

  1. Changes of Chemical Composition and Crystalline of Compressed Chinese Fir Wood in Heating Fixation

    Institute of Scientific and Technical Information of China (English)

    Tang Xiaoshu; Zhao Guangjie; Nakao Tetsuya

    2004-01-01

    The changes in relative crystalline, chemical composition and internal structure of compressed Chinese fir wood after different heating fixations were found strictly related to fixation conditions. The compressed wood powders were fixed either by heating at different temperatures all resulting in a 10% recovery, or by incubating at 180 °C for different periods with subsequent recovery levels. Both X-ray diffraction and infrared absorption of those samples have been measured. Relative crystalline increases at early stage of heating fixation, and then decreased gradually. Hemicellulose and lignin decomposition were induced by the fixation process, especially at 180 °C, and lignin was degraded actively. Furthermore, absorbed water was lost after heating, but cellulose did not change markedly. Although different fixation pathways can result in the same recovery level, the major chemical reactions underlying them vary, which is consistent with the difference of fixation mechanisms.

  2. Transverse Emittance Measurements In High-power Fir Fel Energy-recovery Linac

    CERN Document Server

    Bolotin, V P; Matveenko, A N; Shevchenko, O A; Vinokurov, N A

    2004-01-01

    50 MeV accelerator-recirculator of Siberian Center for Photochemical Research has been designed to drive the FIR FEL with an average power of up to 10 kW in the wavelengths region from 5 to 200 μm. The first stage with the beam energy of 14 MeV was put into operation and laser power of about 200 W on 150 μm was achieved recently [1]. Transverse emittance measurements are carried out online in a number of locations along the beam-line. OTR screens and video-cameras are used to capture the beam shape images, video signal is digitized by a frame grabber and the pictures are processed further. Online measurements allow the accelerator parameters to be optimized to minimize the emittance growth, which is essential to the FEL operation. The transverse emittance measurements system and data processing techniques are presented in this paper.

  3. A Low Power/Area Digital FIR Filter Design Based on PRF Framework

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A novel DSP to ASIC (Application Specific Integrated Circuit) architecture desig n methodology is presented in this paper for reducing power/area consumption. Traditional methods always focus on optimizing hardware structure or algorithm sep arately. The authors propose a new method called PRF (ParallelingReducing-Fol-ding) framework to combine hardware optimization with algorithm simplification. In the first step,paralleling, unfolding technology is applied to divide one data path into several channels and expose the redundancy of the algorithm. In the second step, reducing,decoupling theory is used to reduce computational complexity.In the last step, folding, timemultiplexing method is used to merge similar components. As an exoteric methodology framework, many optimization methods can be integrated into the PRF framework.To optimize a 3N taps FIR (Fincte Impact Response)and obtain a content result,PRF methodology framework is applied.

  4. Round-Off Noise of Multiplicative FIR Filters Implemented on an FPGA Platform

    Directory of Open Access Journals (Sweden)

    Jean-Jacques Vandenbussche

    2014-03-01

    Full Text Available The paper analyzes the effects of round-off noise on Multiplicative Finite Impulse Response (MFIR filters used to approximate the behavior of pole filters. General expressions to calculate the signal to round-off noise ratio of a cascade structure of Finite Impulse Response (FIR filters are obtained and applied on the special case of MFIR filters. The analysis is based on fixed-point implementations, which are most common in digital signal processing algorithms implemented in Field-Programmable Gate-Array (FPGA technology. Three well known scaling methods, i.e., L2 bound; infinity bound and absolute bound scaling are considered and compared. The paper shows that the ordering of the MFIR stages, in combination with the scaling methods, have an important impact on the round-off noise. An optimal ordering of the stages for a chosen scaling method can improve the round-off noise performance by 20 dB.

  5. Ability of natural extracts to limit mold growth on Douglas-fir sapwood

    Directory of Open Access Journals (Sweden)

    Michal Maoz

    2012-11-01

    Full Text Available The ability of selected plant extracts from wood and foliage to inhibit mold regrowth on fungal colonized wood was evaluated on Douglas-fir sapwood. Most foliage extracts produced some inhibition of Graphium or Trichoderma species, but isolations of other fungi increased following treatment. Five out of eight wood extracts produced 50% reductions in isolations, and those from Alaska cedar, western juniper, and incense cedar produced at least 80% reductions. The results indicate that wood extracts may be useful for reducing the incidence of mold on wood products, but none of the materials evaluated completely inhibited the test fungi. These extracts may provide a useful value-added application for by-products of lumber production from these species.

  6. Resources of Digital FIR Filters Hardware Implementation in FPGAs for Digital Image Processing in Real Time

    Directory of Open Access Journals (Sweden)

    Peter Kulla

    2004-01-01

    Full Text Available The main image information content, from the human visual system viewing point, is focused into whole colorimetric and spatial informations. Because every image is result of some previous processes, the goal for all standard image processing methods is improvement colorimetric and spatial image parameters in relation maximum information content by the complicated and expensive systems for digital image processing in (quasireal time [1] based on the flash signal (multiprocessors. Some single-purpose applications do not need the robust and flash systems for DIP and be enough for their use single digital filters with suitable hardware implementation. In the contribution discussed problem is therefore focused on the short description of FIR digital tilters and their hardware implementation in FPGAs-Xilinx for usage in the image processing in real time include obtained experimental results.

  7. Multidimensional Systolic Arrays of LMS AlgorithmAdaptive (FIR Digital Filters

    Directory of Open Access Journals (Sweden)

    Bakir A. R. Al-Hashemy

    2009-01-01

    Full Text Available A multidimensional systolic arrays realization of LMS algorithm by a method of mapping regular algorithm onto processor array, are designed. They are based on appropriately selected 1-D systolic array filter that depends on the inner product sum systolic implementation. Various arrays may be derived that exhibit a regular arrangement of the cells (processors and local interconnection pattern, which are important for VLSI implementation. It reduces latency time and increases the throughput rate in comparison to classical 1-D systolic arrays. The 3-D multilayered array consists of 2-D layers, which are connected with each other only by edges. Such arrays for LMS-based adaptive (FIR filter may be opposed the fundamental requirements of fast convergence rate in most adaptive filter applications.

  8. Performance analysis of adjustable window based FIR filter for noisy ECG Signal Filtering

    Directory of Open Access Journals (Sweden)

    N. Mahawar

    2013-09-01

    Full Text Available Recording of the electrical activity associated to heart functioning is known as Electrocardiogram (ECG. ECG is a quasi-periodical, rhythmically signal synchronized by the function of the heart, which acts as a generator of bioelectric events. ECG signals are low level signals and sensitive to external contaminations. Electrocardiogram signals are often corrupted by noise which may have electrical or electrophysiological origin. The noise signal tends to alter the signal morphology, thereby hindering the correct diagnosis. In order to remove the unwanted noise, a digital filtering technique based on adjustable windows is proposed in this paper. Finite Impulse Response (FIR low pass is designed using windowing method for the ECG signal. The results obtained from different techniques are compared on the basis of popularly used signal error measures like SNR, PRD, PRD1, and MSE.

  9. A VHDL Implementation of Direct, Pipelined and Distributed Arithmetic FIR Filters

    Directory of Open Access Journals (Sweden)

    Sucharitha. L

    2013-03-01

    Full Text Available Digital filters are typically used to modify or alter the attributes of a signal in the time or frequency domain. In this project, various FIR filter structures will be studied and implemented in VHDL. Basic arithmetic blocks to carry out DSP on FPGAs will be discussed. The very popular LUT based approach for arithmetic circuit implementation will be presented. The conventional PDSP MAC and Distributed arithmetic MAC units will be implemented and their performance will be compared. Usage of Pipelining in multipliers for improving the speed will also be discussed. The ModelSim XE simulator will be used to simulate the design at various stages. Xilinx synthesis tool (XST will be used to synthesize the design for spartan3E family FPGA (XC3S500E. Xilinx Placement {&} Routing tools will be used for backend, design optimization and I/O routing

  10. Renewable phenols production by catalytic microwave pyrolysis of Douglas fir sawdust pellets with activated carbon catalysts.

    Science.gov (United States)

    Bu, Quan; Lei, Hanwu; Wang, Lu; Wei, Yi; Zhu, Lei; Liu, Yupeng; Liang, Jing; Tang, Juming

    2013-08-01

    The effects of different activated carbon (AC) catalysts based on various carbon sources on products yield and chemical compositions of upgraded pyrolysis oils were investigated using microwave pyrolysis of Douglas fir sawdust pellets. Results showed that high amounts of phenols were obtained (74.61% and 74.77% in the upgraded bio-oils by DARCO MRX (wood based) and DARCO 830 (lignite coal based) activated carbons, respectively). The catalysts recycling test of the selected catalysts indicated that the carbon catalysts can be reused for at least 3-4 times and produced high concentrations of phenol and phenolic compounds. The chemical reaction mechanism for phenolics production during microwave pyrolysis of biomass was analyzed.

  11. Transmission of a Gammabaculovirus within Cohorts of Balsam Fir Sawfly (Neodiprion abietis Larvae

    Directory of Open Access Journals (Sweden)

    Christopher J. Lucarotti

    2012-10-01

    Full Text Available Nucleopolyhedroviruses (NPV: Gammabaculovirus: Baculoviridae of diprionid sawflies (Diprionidae: Hymenoptera are highly host specific and only infect the midgut epithelium. While still alive, infected sawfly larvae excrete NPV-laden diarrhea that contaminates food sources. The diarrhea can then be consumed by conspecific larvae, resulting in rapid horizontal transmission of the virus. To better understand the efficacy of Gammabaculovirus-based biological control products, the horizontal spread of such a virus (NeabNPV within cohorts of balsam fir sawfly (Neodiprion abietis larvae was studied by introducing NeabNPV-treated larvae into single-cohort groups at densities similar to those observed during the increasing (field study and peak (laboratory study phases of an outbreak. In field studies (~200 N. abietis larvae/m2 of balsam fir (Abies balsamea foliage, NeabNPV-induced mortality increased positively in a density-dependent manner, from 23% (in control groups to 51% with the addition of one first-instar NeabNPV-treated larva, to 84% with 10 first–instar-treated larvae. Mortality was 60% and 63% when one or 10 NeabNPV-treated third-instar larva(e, respectively, were introduced into groups. Slightly higher levels of NeabNPV-induced mortality occurring when NeabNPV-treated larvae were introduced into first- rather than third-instar cohorts suggests that early instars are more susceptible to the virus. In the laboratory (~1330 N. abietis larvae/ m2 of foliage, NeabNPV-caused mortality increased from 20% in control groups to over 80% with the introduction of one, five or 10 NeabNPV-treated larvae into treatment groups of first-instar larvae.

  12. Implementasi Filter Finite Impulse Response (FIR Window Hamming dan Blackman menggunakan DSK TMS320C6713

    Directory of Open Access Journals (Sweden)

    LITA LIDYAWATI

    2016-02-01

    Full Text Available ABSTRAK Filter didefinisikan sebagai proses atau rangkaian yang melewatkan pita frekuensi tertentu yang diinginkan dan meredam pita frekuensi lainnya. Salah satu metode perancangan filter digital Finite Impulse Response (FIR adalah metode windowing. Dalam penelitian ini digunakan jenis window Hamming dan Blackman. Simulasi dilakukan dengan menggunakan software Matlab dengan memasukan frekuensi passband, frekuensi stopband, ripple passband, dan stopband attenuation. Dengan frekuensi sampling sebesar 15000 Hz, frekuensi passband sebesar 3000 Hz, frekuensi stopband sebesar 5000 Hz. Setelah simulasi dilakukan implementasi filter dengan parameter yang sama menggunakan DSK TMS 320C6713 dengan bantuan software CCS. Simulasi dan implementasi dilakukan pada semua band frekuensi. Hasil pengujian terhadap implementasi filter adalah respon magnitude, frekuensi cut-off, bandwidth, dan faktor kualitas dengan hasil simulasi tidak menunjukkan perbedaan yang signifikan. Kata kunci: filter digital, windowing, Hamming, Blackman, frekuensi cut-off . ABSTRACT Filter is defined as a process or series that skip certain desired frequency band and other frequency bands drown. One method of designing a digital filter Finite Impulse Response (FIR is a windowing method. This study used the type of window Hamming and Blackman. Simulations performed using Matlab software by inserting a frequency passband, stopband frequency, passband ripple, and stopband attenuation. With a sampling frequency of 15,000 Hz, a frequency of 3000 Hz passband, stopband frequency of 5000 Hz. After the simulation is completed, implementation of the filter with the same parameters using TMS 320C6713 DSK with the help of software CCS. Simulation and implmentasi performed on all frequency bands. The test results of the implementation of the filter is the Magnitude response, the cut-off frequency, bandwidth, and quality factor with simulation results showed no significant difference. Keywords: digital

  13. Effects of Different Management Regimes for Cutover Areas on Soil Carbon Storage in Chinese Fir Plantations

    Institute of Scientific and Technical Information of China (English)

    Fang Xi; Tian Dalun; Xiang Wenhua

    2006-01-01

    Based on data collected (through local observations) for several consecutive years,comparative analyses of Chinese fir plantations in Huitong,Hunan,were made.Results show that,before harvesting,carbon storage in forest soils in these 22-year-old plantations (0-60 cm)amounted to 160.38 t/hm2;1 year after a 100%clearcutting,loss of carbon storage in the soil (0-60 cm) of cutover areas was 35.00%;2 years later,the rate was 44.65%;and,after 3 years,the rate was 43.93%compared with a control area of a standing forest.Three years after 50%thinning and 100%clear-cutting,the loss of carbon storage in the soil (0-60 cm) of cutover areas was 16.14 and 45.15%,respectively.There existed an evident difference in carbon storage in the soil (0-60 cm) of cutover areas in four kinds of management regimes,which followed the order:closed Chinese fir forests (108.20 t/hm2)>fallow lands after farming (92.68 t/hm )>commercial forests (85.80 t/hm2)>naturally regenerated forestlands after harvesting.Carbon storage in unbumt soil(0-45 cm) reached 73.36 t/hm2,which was 15.20 t/hm2 higher than that in the soil of burnt areas.A total of 20.7%of carbon storage in the soil (0-45 cm) of burnt areas was lost 40 days after burning.Carbon storage in surface soil (0-15 cm) was higher than in the lower soil layer,which amounted to 30.04%(0-60 cm) and 53.52%(0-30 cm) of total carbon storage in the soil.

  14. Fermentative high-titer ethanol production from Douglas-fir forest residue without detoxification using SPORL: high SO2 loading at low temperature

    Science.gov (United States)

    Feng Gu; William Gilles; Roland Gleisner; J.Y. Zhu

    2016-01-01

    This study evaluated high sulfur dioxide (SO2) loading in applying Sulfite Pretreatment to Overcome the Recalcitrance of Lignocelluloses (SPORL) to Douglas-fir forest residue (FS-10) for ethanol production through yeast fermentation. Three pretreatments were conducted at 140

  15. Basal area growth, carbon isotope discrimination, and intrinsic water use efficiency after fertilization of Douglas-fir in the Oregon Coast Range

    Science.gov (United States)

    Many hectares of intensively managed Douglas-fir (Pseudotsuga menziesii Mirb. Franco) stands in western North America are fertilized with nitrogen to increase growth rates. Understanding the mechanisms of response facilitates prioritization of stands for treatment. The objective ...

  16. Ten Years of Rainfall and Community-Based Streamflow Monitoring in the Tropical Montane Cloud Forest Region of Central Veracruz, Mexico: What Do These Data Tell Us?

    Science.gov (United States)

    Holwerda, F.; Aranda-Delgado, E.; Castilleja-Delgado, E.; Munoz-Villers, L.

    2016-12-01

    Montane ecosystems and the water resources provided by them play a crucial role in the development and growth of cities and the productive sector in Mexico. For the planning and sustainable management of these resources, it is necessary to quantify the key hydrological components and have (at least some) basic understanding of the water cycle at the operational watershed-scale. However, the difficulty of implementing and maintaining rainfall-discharge observation networks due to the lack of financial resources and well-trained personnel, coupled with poor accessibility and safety, as well as the complexity of the biophysical and climatic conditions in montane regions have hampered progress in hydrological research and the generation of basic knowledge for the benefit of society. In 2005, research-motivated measurements of rainfall (P) and community-based observations of streamflow (Q) were initiated independently in the tropical montane cloud forest (TMCF) region of central Veracruz, Mexico. In this presentation, we will explore these data to study the seasonal and annual P inputs and Q outputs of the ca. 11,000 ha Pixquiac river watershed as observed during the past ten years (2005-2015). The P data used in this analysis include continuous measurements from the major recharge zone within the study area (2000-2300 m asl), supplemented with observations from lower and higher altitudes to determine the P-elevation relationship. The Q data of the Pixquiac river consist of monthly measurements made near the outlet of the watershed (1300-1400 m asl) by citizen volunteers using the Global Water Watch methodology. We expect that these observations will contribute to an improved understanding of the hydrometeorology of mesoscale TMCF watersheds in central Veracruz, which is a prerequisite for sustainable planning and management of the water resources in this region.

  17. Assessment of variations in taxonomic diversity, forest structure, and aboveground biomass using remote sensing along an altitudinal gradient in tropical montane forest of Costa Rica

    Science.gov (United States)

    Robinson, C. M.; Saatchi, S. S.; Clark, D.; Fricker, G. A.; Wolf, J.; Gillespie, T. W.; Rovzar, C. M.; Andelman, S.

    2012-12-01

    This research sought to understand how alpha and beta diversity of plants vary and relate to the three-dimensional vegetation structure and aboveground biomass along environmental gradients in the tropical montane forests of Braulio Carrillo National Park in Costa Rica. There is growing evidence that ecosystem structure plays an important role in defining patterns of species diversity and along with abiotic factors (climate and edaphic) control the phenotypic and functional variations across landscapes. It is well documented that strong subdivisions at local and regional scales are found mainly on geologic or climate gradients. These general determinants of biodiversity are best demonstrated in regions with natural gradients such as tropical montane forests. Altitudinal gradients provide a landscape scale changes through variations in topography, climate, and edaphic conditions on which we tested several theoretical and biological hypotheses regarding drivers of biodiversity. The study was performed by using forest inventory and botanical data from nine 1-ha plots ranging from 100 m to 2800 m above sea level and remote sensing data from airborne lidar and radar sensors to quantify variations in forest structure. In this study we report on the effectiveness of relating patterns of tree taxonomic alpha diversity to three-dimensional structure of a tropical montane forest using lidar and radar observations of forest structure and biomass. We assessed alpha and beta diversity at the species, genus, and family levels utilizing datasets provided by the Terrestrial Ecology Assessment and Monitoring (TEAM) Network. Through the comparison to active remote sensing imagery, our results show that there is a strong relationship between forest 3D-structure, and alpha and beta diversity controlled by variations in abiotic factors along the altitudinal gradient. Using spatial analysis with the aid of remote sensing data, we find distinct patterns along the environmental gradients

  18. Coalescent models reveal the relative roles of ancestral polymorphism, vicariance, and dispersal in shaping phylogeographical structure of an African montane forest robin.

    Science.gov (United States)

    Bowie, Rauri C K; Fjeldså, Jon; Hackett, Shannon J; Bates, John M; Crowe, Timothy M

    2006-01-01

    Although many studies have documented the effect of glaciation on the evolutionary history of Northern Hemisphere flora and fauna, this study is the first to investigate how the indirect aridification of Africa caused by global cooling in response to glacial cycles at higher latitudes has influenced the evolutionary history of an African montane bird. Mitochondrial DNA sequences from the NADH 3 gene were collected from 283 individual Starred Robins (Pogonocichla stellata, Muscicapoidea). At least two major vicariant events, one that separated the Albertine Rift from all but the Kenyan Highlands around 1.3-1.2 Myrs BP, and another that separated the Kenyan Highlands from the northern Eastern Arc, and the northern Eastern Arc from the south-central Eastern Arc between 0.9 and 0.8 Myrs BP appear to underlie much of the observed genetic diversity and structure within Starred Robin populations. These dates of divergence suggest a lack of recurrent gene flow; although the Albertine Rift and south-central Eastern Arc share haplotypes, based on coalescent analyses this can confidently be accounted for by ancestral polymorphism as opposed to recurrent gene flow. Taken collectively, strong evidence exists for recognition of four major ancestral populations: (1) Kenyan Highlands (subspecies keniensis), (2) Albertine Rift (ruwenzori), (3) northern Eastern Arc (helleri), and (4) south-central Eastern Arc, Ufipa and the Malawi Rift (orientalis). The estimated divergence times cluster remarkably around one of the three estimated peaks of aridification in Africa during the Plio-Pleistocene centred on 1 Myrs BP. Further, time to most recent common ancestor (TMRCA) estimates (1.7-1.6 Myrs BP) of gene divergence between the Albertine Rift and the other montane highlands corresponds closely with a second estimated peak of aridification at about 1.7 Myrs BP. Collectively, these results suggest that aridification of Africa in response to glaciation at higher latitudes during the

  19. Genera variation of tropical mid-upper montane rainforest inferred from a marine pollen record in southern Philippines during the glacial-interglacial cycle

    Science.gov (United States)

    Bian, Y.

    2015-12-01

    Tropical vegetation is the most outstanding and obvious feature of South-East Asia, and it is expected to provide valuable information for the palaeoclmatic conditions. Pollen records from the tropical West Pacific indicate that the tropical vegetation is much sensitive to the environment and climate change, and their good correspondence with palaeocliamte change in glacial/interglacial timescales. It is shown that the range of the tropical montane rainforest was affected by the temperature change during the glacial cycle. But, from some marine core, the genera variation of tropical mid-upper montane pollen record is also distinct during the glacial cycle. In this study, examination of the pollen content of marine core MD06-3075 taken from Davao Gulf in the Southern Philippines reveals a ~116,000 year record of tropical vegetation change as well as the influence of the environment and climate variability on the ecosystem of the tropical area. Chronology was determined by 16 AMS 14C dates and a detailed oxygen isotope record. A high representation of pollen from tropical upper montane rainforest (mainly Podocarpus) (40-60%) during the last glacial period indicates that this forest type extended to lower attitudes. And the genera variations of the tropical mid-upper montane rainforest exist between the Phyllocladus and Podocarpus with the environment and climate changing. The pollen content of Phyllocladus is much high in marine isotope stage (MIS) 5, but Podocarpus is much higher in the glacial period. During the onset of MIS 5a and 5c, the percentage of Phyllocladus pollen declines dramatically. Vegetation investigation in Mindanao, shows that Podocarpus exists in altitude ranging from 1,200-1,700 m, and Phyllocladus appear in altitude range from 1700-2100 m, but is more abundant above the 2,400 m. Thus, Phyllocladus might be more sensitive to the temperature change. Then, in this study, the pollen content of is much high during the interglacial period

  20. Temporal and spatial patterns in the emigrations of the army ant Dorylus (Anomma) molestus in the montane forest of Mt Kenya

    DEFF Research Database (Denmark)

    Schöning, Caspar; Njagi, Washington M.; Franks, Nigel R.

    2005-01-01

    1. The emigration behaviour of the army ant Dorylus (Anomma) molestus was studied in the montane forest of Mt Kenya. This species forages by massive swarm raids (mean width 10.3 m ± 4.6 m SD), which are assumed to have a strong negative impact on the densities of prey populations. 2. For non-repr...... in intraspecific battles. Possible reasons for the absence of fights between colonies despite apparently fierce intraspecific competition are discussed....

  1. Using sensitive montane amphibian species as indicators of hydroclimatic change in meadow ecosystems of the Sierra Nevada, California

    Science.gov (United States)

    Peek, R.; Viers, J.; Yarnell, S. M.

    2012-12-01

    Climate change can affect sensitive species and ecosystems in many ways, yet sparse data and the inability to apply various climate models at functional spatial scales often prevents relevant research from being utilized in conservation management plans. Climate change has been linked to declines and disturbances in a multitude of species and habitats, and in California, one of the greatest climatic concerns is the predicted reduction in mountain snowpack and associated snowmelt. These decreases in natural storage of water as snow in mountain regions can affect the timing and variability of critical snowmelt runoff periods—important seasonal signals that species in montane ecosystems have evolved life history strategies around—leading to greater intra-annual variability and diminished summer and fall stream flows. Although many species distribution models exist, few provide ways to integrate continually updated and revised Global Climate Models (GCMs), hydrologic data unique to a watershed, and ecological responses that can be incorporated into conservation strategies. This study documents a novel and applicable method of combining boosted regression tree (BRT) modeling and species distributions with hydroclimatic data as a potential management tool for conservation. Boosted regression trees are suitable for ecological distribution modeling because they can reduce both bias and variance, as well as handle sharp discontinuities common in sparsely sampled species or large study areas. This approach was used to quantify the effects of hydroclimatic changes on the distribution of key riparian-associated amphibian species in montane meadow habitats in the Sierra Nevada at the sub-watershed level. Based on modeling using current species range maps in conjunction with three climate scenarios (near, mid, and far), extreme range contractions were observed for all sensitive species (southern long-toed salamander, mountain yellow-legged frog, Yosemite toad) by the year

  2. Chemical composition and antifungal activity of the essential oil of Douglas fir (Pseudosuga menziesii Mirb. Franco from Serbia

    Directory of Open Access Journals (Sweden)

    VELE TEŠEVIĆ

    2009-09-01

    Full Text Available The chemical composition of the essential oil of fresh young needles with twigs of Douglas fir (Pseudosuga menziesii Mirb. Franco obtained by hydrodistillation were analyzed by gas chromatography (GC and gas chromatography–mass spectrometry (GC–MS. Ten compounds, accounting for 94.26 % of the oil, were identified. The main compounds found were bornyl acetate (34.65 %, camphene (29.82 %, a-pinene (11.65 % and santene (5.45 %. The antifungal activity of the essential oil was tested against various fungal species. The minimum inhibitory concentration of Douglas fir essential oil ranged from 1.5 to 4 µg mL-1. The fungi most sensitive to the tested oil were Phomopsis helianthi, while Penicillium species, along with Microsporum canis, were the most resistant. Compared to the commercial fungicidal agent bifonazole, the studied essential oil demonstrated higher antifungal activity.

  3. Optimal design of FIR high pass filter based on L1 error approximation using real coded genetic algorithm

    Directory of Open Access Journals (Sweden)

    Apoorva Aggarwal

    2015-12-01

    Full Text Available In this paper, an optimal design of linear phase digital finite impulse response (FIR highpass (HP filter using the L1-norm based real-coded genetic algorithm (RCGA is investigated. A novel fitness function based on L1 norm is adopted to enhance the design accuracy. Optimized filter coefficients are obtained by defining the filter objective function in L1 sense using RCGA. Simulation analysis unveils that the performance of the RCGA adopting this fitness function is better in terms of signal attenuation ability of the filter, flatter passband and the convergence rate. Observations are made on the percentage improvement of this algorithm over the gradient-based L1 optimization approach on various factors by a large amount. It is concluded that RCGA leads to the best solution under specified parameters for the FIR filter design on account of slight unnoticeable higher transition width.

  4. Critical zone properties control the fate of nitrogen during experimental rainfall in montane forests of the Colorado Front Range

    Science.gov (United States)

    Hinckley, Eve-Lyn S.; Ebel, Brian A.; Barnes, Rebecca T.; Murphy, Sheila F.; Anderson, Suzanne P.

    2017-01-01

    Several decades of research in alpine ecosystems have demonstrated links among the critical zone, hydrologic response, and the fate of elevated atmospheric nitrogen (N) deposition. Less research has occurred in mid-elevation forests, which may be important for retaining atmospheric N deposition. To explore the fate of N in the montane zone, we conducted plot-scale experimental rainfall events across a north–south transect within a catchment of the Boulder Creek Critical Zone Observatory. Rainfall events mimicked relatively common storms (20–50% annual exceedance probability) and were labeled with 15N-nitrate (NO3−">NO−3NO3−) and lithium bromide tracers. For 4 weeks, we measured soil–water and leachate concentrations of Br−, 15NO3−,">15NO−3,15NO3−, and NO3−">NO−3NO3− daily, followed by recoveries of 15N species in bulk soils and microbial biomass. Tracers moved immediately into the subsurface of north-facing slope plots, exhibiting breakthrough at 10 and 30 cm over 22 days. Conversely, little transport of Br− or 15NO3−">15NO−315NO3− occurred in south-facing slope plots; tracers remained in soil or were lost via pathways not measured. Hillslope position was a significant determinant of soil 15N-NO3−">NO−3NO3− recoveries, while soil depth and time were significant determinants of 15N recovery in microbial biomass. Overall, 15N recovery in microbial biomass and leachate was greater in upper north-facing slope plots than lower north-facing (toeslope) and both south-facing slope plots in August; by October, 15N recovery in microbial N biomass within south-facing slope plots had increased substantially. Our results point to the importance of soil properties in controlling the fate of N in mid-elevation forests during the summer season.

  5. Soil Organic Carbon Storage and Stability in the Aspen-Conifer Ecotone in Montane Forests in Utah, USA

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    Mercedes Román Dobarco

    2014-04-01

    Full Text Available To assess the potential impact of conifer encroachment on soil organic carbon (SOC dynamics and storage in montane aspen-conifer forests from the interior western US, we sampled mineral soils (0–15 cm across the aspen-conifer ecotones in southern and northern Utah and quantified total SOC stocks, stable SOC (i.e., mineral-associated SOC (MoM, labile SOC (i.e., light fraction (LF, decomposable (CO2 release during long-term aerobic incubations and soluble SOC (hot water extractable organic carbon (HWEOC. Total SOC storage (47.0 ± 16.5 Mg C ha−1 and labile SOC as LF (14.0 ± 7.10 Mg C ha−1, SOC decomposability (cumulative released CO2-C of 5.6 ± 3.8 g C g−1 soil or HWEOC (0.6 ± 0.6 mg C g−1 soil did not differ substantially with vegetation type, although a slight increase in HWEOC was observed with increasing conifer in the overstory. There were statistically significant differences (p = 0.035 in stable MoM storage, which was higher under aspen (31.2 ± 15.1 Mg C ha−1 than under conifer (22.8 ± 9.0 Mg C ha−1, with intermediate values under mixed (25.7 ± 8.8 Mg C ha−1. Texture had the greatest impact on SOC distribution among labile and stable fractions, with increasing stabilization in MoM and decreasing bio-availability of SOC with increasing silt + clay content. Only at lower silt + clay contents (40%–70% could we discern the influence of vegetation on MoM content. This highlights the importance of chemical protection mechanisms for long-term C sequestration.

  6. Nitrogen cycling in canopy soils of tropical montane forests responds rapidly to indirect N and P fertilization.

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    Matson, Amanda L; Corre, Marife D; Veldkamp, Edzo

    2014-12-01

    Although the canopy can play an important role in forest nutrient cycles, canopy-based processes are often overlooked in studies on nutrient deposition. In areas of nitrogen (N) and phosphorus (P) deposition, canopy soils may retain a significant proportion of atmospheric inputs, and also receive indirect enrichment through root uptake followed by throughfall or recycling of plant litter in the canopy. We measured net and gross rates of N cycling in canopy soils of tropical montane forests along an elevation gradient and assessed indirect effects of elevated nutrient inputs to the forest floor. Net N cycling rates were measured using the buried bag method. Gross N cycling rates were measured using (15) N pool dilution techniques. Measurements took place in the field, in the wet and dry season, using intact cores of canopy soil from three elevations (1000, 2000 and 3000 m). The forest floor had been fertilized biannually with moderate amounts of N and P for 4 years; treatments included control, N, P, and N + P. In control plots, gross rates of NH4 (+) transformations decreased with increasing elevation; gross rates of NO3 (-) transformations did not exhibit a clear elevation trend, but were significantly affected by season. Nutrient-addition effects were different at each elevation, but combined N + P generally increased N cycling rates at all elevations. Results showed that canopy soils could be a significant N source for epiphytes as well as contributing up to 23% of total (canopy + forest floor) mineral N production in our forests. In contrast to theories that canopy soils are decoupled from nutrient cycling in forest floor soil, N cycling in our canopy soils was sensitive to slight changes in forest floor nutrient availability. Long-term atmospheric N and P deposition may lead to increased N cycling, but also increased mineral N losses from the canopy soil system.

  7. Transpiration of montane Pinus sylvestris L. and Quercus pubescens Willd. forest stands measured with sap flow sensors in NE Spain

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    R. Poyatos

    2005-01-01

    Full Text Available Stand transpiration was measured during the 2003 and 2004 growing seasons using heat dissipation sap flow sensors in a Scots pine (Pinus sylvestris L. and a pubescent oak (Quercus pubescens Willd. forests located in a montane area of the Eastern Pyrenees (NE Spain. The first aim of the study was to assess the differences in quantitative estimates of transpiration (Ec and the response to evaporative demand of the two stands. Over the studied period of 2003, characterised by a severe drought episode during the summer, the oak stand (Ec was only 110 mm compared to the 239 mm transpired by the Scots pine stand, although the ratio of transpiration to reference evapotranspiration (Ec/ET0 in the oak stand compares well with the expected values predicted for low leaf area index (LAI oak forests in southern Europe. Scots pine showed a strong reduction in (Ec/ET0 as the drought developed, whereas pubescent oak was less affected by soil moisture deficits in the upper soil. As a second objective, and given the contrasting meteorological conditions between 2003 and 2004 summer periods, the interannual variability of transpiration was studied in the Scots pine plot. Rainfall during the summer months (June-September in 2003 was almost 40% less than in the same interval in 2004. Accordingly, transpiration was also reduced about 25% in 2003. Finally, Scots pine data from 2003 and 2004 was used to calibrate a simple transpiration model using ET0 and soil moisture deficit (SMD as input variables, and implicitly including stomatal responses to high vapour pressure deficits (Dd and soil water status.

  8. Forest structure, stand composition, and climate-growth response in montane forests of Jiuzhaigou National Nature Reserve, China.

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    Mark W Schwartz

    Full Text Available Montane forests of western China provide an opportunity to establish baseline studies for climate change. The region is being impacted by climate change, air pollution, and significant human impacts from tourism. We analyzed forest stand structure and climate-growth relationships from Jiuzhaigou National Nature Reserve in northwestern Sichuan province, along the eastern edge of the Tibetan plateau. We conducted a survey to characterize forest stand diversity and structure in plots occurring between 2050 and 3350 m in elevation. We also evaluated seedling and sapling recruitment and tree-ring data from four conifer species to assess: 1 whether the forest appears in transition toward increased hardwood composition; 2 if conifers appear stressed by recent climate change relative to hardwoods; and 3 how growth of four dominant species responds to recent climate. Our study is complicated by clear evidence of 20(th century timber extraction. Focusing on regions lacking evidence of logging, we found a diverse suite of conifers (Pinus, Abies, Juniperus, Picea, and Larix strongly dominate the forest overstory. We found population size structures for most conifer tree species to be consistent with self-replacement and not providing evidence of shifting composition toward hardwoods. Climate-growth analyses indicate increased growth with cool temperatures in summer and fall. Warmer temperatures during the growing season could negatively impact conifer growth, indicating possible seasonal climate water deficit as a constraint on growth. In contrast, however, we found little relationship to seasonal precipitation. Projected warming does not yet have a discernible signal on trends in tree growth rates, but slower growth with warmer growing season climates suggests reduced potential future forest growth.

  9. Functional trait trade-offs for the tropical montane rain forest species responding to light from simulating experiments.

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    Mao, Peili; Zang, Runguo; Shao, Hongbo; Yu, Junbao

    2014-01-01

    Differences among tropical tree species in survival and growth to light play a key role in plant competition and community composition. Two canopy species with contrasting functional traits dominating early and late successional stages, respectively, in a tropical montane rain forest of Hainan Island, China, were selected in a pot experiment under 4 levels of light intensity (full, 50%, 30%, and 10%) in order to explore the adaptive strategies of tropical trees to light conditions. Under each light intensity level, the pioneer species, Endospermum chinense (Euphorbiaceae), had higher relative growth rate (RGR), stem mass ratio (SMR), specific leaf area (SLA), and morphological plasticity while the shade tolerant climax species, Parakmeria lotungensis (Magnoliaceae), had higher root mass ratio (RMR) and leaf mass ratio (LMR). RGR of both species was positively related to SMR and SLA under each light level but was negatively correlated with RMR under lower light (30% and 10% full light). The climax species increased its survival by a conservative resource use strategy through increasing leaf defense and root biomass investment at the expense of growth rate in low light. In contrast, the pioneer increased its growth by an exploitative resource use strategy through increasing leaf photosynthetic capacity and stem biomass investment at the expense of survival under low light. There was a trade-off between growth and survival for species under different light conditions. Our study suggests that tree species in the tropical rainforest adopt different strategies in stands of different successional stages. Species in the earlier successional stages have functional traits more advantageous to grow faster in the high light conditions, whereas species in the late successional stages have traits more favorable to survive in the low light conditions.

  10. The Relative Impact of Climate Change on the Extinction Risk of Tree Species in the Montane Tropical Andes.

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    Natalia Tejedor Garavito

    Full Text Available There are widespread concerns that anthropogenic climate change will become a major cause of global biodiversity loss. However, the potential impact of climate change on the extinction risk of species remains poorly understood, particularly in comparison to other current threats. The objective of this research was to examine the relative impact of climate change on extinction risk of upper montane tree species in the tropical Andes, an area of high biodiversity value that is particularly vulnerable to climate change impacts. The extinction risk of 129 tree species endemic to the region was evaluated according to the IUCN Red List criteria, both with and without the potential impacts of climate change. Evaluations were supported by development of species distribution models, using three methods (generalized additive models, recursive partitioning, and support vector machines, all of which produced similarly high AUC values when averaged across all species evaluated (0.82, 0.86, and 0.88, respectively. Inclusion of climate change increased the risk of extinction of 18-20% of the tree species evaluated, depending on the climate scenario. The relative impact of climate change was further illustrated by calculating the Red List Index, an indicator that shows changes in the overall extinction risk of sets of species over time. A 15% decline in the Red List Index was obtained when climate change was included in this evaluation. While these results suggest that climate change represents a significant threat to tree species in the tropical Andes, they contradict previous suggestions that climate change will become the most important cause of biodiversity loss in coming decades. Conservation strategies should therefore focus on addressing the multiple threatening processes currently affecting biodiversity, rather than focusing primarily on potential climate change impacts.

  11. Forest structure, stand composition, and climate-growth response in montane forests of Jiuzhaigou National Nature Reserve, China.

    Science.gov (United States)

    Schwartz, Mark W; Dolanc, Christopher R; Gao, Hui; Strauss, Sharon Y; Schwartz, Ari C; Williams, John N; Tang, Ya

    2013-01-01

    Montane forests of western China provide an opportunity to establish baseline studies for climate change. The region is being impacted by climate change, air pollution, and significant human impacts from tourism. We analyzed forest stand structure and climate-growth relationships from Jiuzhaigou National Nature Reserve in northwestern Sichuan province, along the eastern edge of the Tibetan plateau. We conducted a survey to characterize forest stand diversity and structure in plots occurring between 2050 and 3350 m in elevation. We also evaluated seedling and sapling recruitment and tree-ring data from four conifer species to assess: 1) whether the forest appears in transition toward increased hardwood composition; 2) if conifers appear stressed by recent climate change relative to hardwoods; and 3) how growth of four dominant species responds to recent climate. Our study is complicated by clear evidence of 20(th) century timber extraction. Focusing on regions lacking evidence of logging, we found a diverse suite of conifers (Pinus, Abies, Juniperus, Picea, and Larix) strongly dominate the forest overstory. We found population size structures for most conifer tree species to be consistent with self-replacement and not providing evidence of shifting composition toward hardwoods. Climate-growth analyses indicate increased growth with cool temperatures in summer and fall. Warmer temperatures during the growing season could negatively impact conifer growth, indicating possible seasonal climate water deficit as a constraint on growth. In contrast, however, we found little relationship to seasonal precipitation. Projected warming does not yet have a discernible signal on trends in tree growth rates, but slower growth with warmer growing season climates suggests reduced potential future forest growth.

  12. [Spatial analysis of LAIe of montane evergreen broad-leaved forest in southwest Sichuan, Northwest China, based on image texture].

    Science.gov (United States)

    Zhao, An-Jiu; Yang, Chang-Qing; Liao, Cheng-Yun

    2014-11-01

    Optical remote sensing is still one of the most attractive choices for obtaining leaf area index (LAI) information, but currently may be derived from remotely sensed data with limited accuracy. Effective leaf area index (LAIe) of montane evergreen broad-leaved forest in southwest Sichuan was inventoried and assessed in 83 sample field plots of 20 m x 20 m using different types of image processing techniques, including simple spectral band, simple spectral band ratios and principal component. Texture information was extracted by gray level co-occurrence matrices (GLCM) from different types of processing image. The results showed that there were correlations of different degrees between LAIe and texture parameters, and highly significant correlations were observed between LAIe with the homogeneity of the B1 band, B1/B4 band ratio or principal component PC1. Using texture information of remotely sensed data as auxiliary variables, we developed geostatistics models. Compared with the model based on NDVI auxiliary variable, the accuracy of LAIe were improved, presenting an increase by 5.3% with the homogeneity of the B1 band, 11.0% with the homogeneity B1/B4 band ratio, and 14.5% with the homogeneity principal component PC1, and the statistical errors were also reduced to some extent. The optimal LAIe model of spatial geostatistics was obtained when taking NDVI and homogeneity principal component PC1 as auxiliary variables (R2 = 0.840, RMSE = 0.212). Our results provided a new way to estimate regional spatial distribution of LAI using other auxiliary variables besides the vegetation index.

  13. Floristic diversity and regeneration status of woody plants in Zengena Forest, a remnant montane forest patch in northwestern Ethiopia

    Institute of Scientific and Technical Information of China (English)

    Desalegn Tadele; Ermias Lulekal; Destaw Damtie; Adane Assefa

    2014-01-01

    The study was conducted at Zengena forest, a fragmented remnant montane forest in northwestern Ethiopia, which surrounds Lake Zengena. The purpose was to assess the species composition, diversity and the regeneration status of woody plants. A total of 27 plots of 20 m × 20 m were sampled along the line transects laid down the altitudinal gradient from the edge of the forest encompassing the lake to the edge of the lake in eight aspects. In each plot, woody species were counted and the diameter at breast height and the height of trees and shrubs were measured. A total of 50 woody species belonging to 31 families were found, of which 17 (34%) were trees, 7 (14%) trees or shrubs, 23 (46%) shrubs and 3 (6%) lianas. The overall Shannon-Wiener diversity and evenness indices of woody species were 2.74 and 0.7, respectively. Clausena anisata had the highest relative density (23.5%), Rapanea rhododendroides the highest relative frequency (6.5%) and Prunus afri-cana the highest relative dominance (45%) and importance value index (IVI, 51.6). The total basal area and density of woody plants were 22.3 m2⋅ha-1 and 2,202 individuals⋅ha-1, respectively. The population structure showed variations among woody plants and revealed varied regeneration patterns of different species. The importance value index and population structure revealed that some species are threatened and need prioritiza-tion for conservation measures. The results suggest that remnant forest patches in the highlands of northern Ethiopia host several woody plant species that are almost disappearing in other areas due to deforestation.

  14. Climate change amplifies gross nitrogen turnover in montane grasslands of Central Europe both in summer and winter seasons

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    Chen, Zhe; Wang, Changhui; Unteregelsbacher, Sebastian; Lu, Haiyan; Gschwendtner, Silvia; Gasche, Rainer; Kolar, Allison; Schloter, Michael; Butterbach-Bahl, Klaus; Dannenmann, Michael

    2016-04-01

    The carbon and nitrogen rich soils of montane grasslands are exposed to above average warming and to altered precipitation patterns as a result of global change. In order to investigate the consequences of climatic change for soil nitrogen turnover, we translocated intact plant-soil mesocosms along an elevational gradient. Following three years of equilibration, we monitored the dynamics of gross nitrogen turnover and ammonia oxidizing microbes over an entire year. Gross nitrogen turnover and gene levels of ammonia oxidizing bacteria (AOB) and archaea (AOA) showed pronounced seasonal dynamics. While both summer and winter periods equally contributed to cumulative annual N turnover, the highest gross N turnover and abundance of ammonia oxidizers were observed in frozen soil of climate change sites due to physical liberation of organic substrates and their rapid turnover in the unfrozen soil water film. The control site never experienced soil freezing due to a significant insulating snowpack. Climate change conditions accelerated gross N mineralization by 250% on average. The AOB community benefited more from increased soil ammonium production under climate change conditions than the AOA community and thus accounted for a significant increase in gross nitrification rates. Climate change impacts were restricted to the 2-6 cm topsoil and rarely occurred at 12-16 cm depth, where generally much lower N turnover was observed. Mineralization pulses in a changing climate may result in soil organic matter loss with their associated negative impacts on key soil functions. In this context, N cycling processes in frozen soil can be a hot spot for gross N turnover and thus be of paramount importance for understanding seasonal patterns, annual sum of N turnover and possible climate change feedbacks.

  15. An annotated checklist of trees and relatives in tropical montane forests from southeast Peru: the importance of continue collecting

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    William Farfan-Rios

    2015-10-01

    Full Text Available The tropical Andes and adjacent Amazon are Earth’s highest biodiversity hotspot. Manu National Park in southeastern Peru encompasses an entire watershed, ranging from Andean highlands to Amazonian lowlands, and is a megadiverse landscape on the Andes to Amazon transition. Here we present an annotated checklist of trees and related species is along an elevation gradient in the Manu Biosphere Reserve that runs from sub-montane forests at 800 m elevation up to the tree line at 3625 m. Based on a network of 21 1-hectare permanent tree plots and botanical explorations, the floristic information is systematized by elevation ranges, geographical distribution and endemism. These preliminary results show 1108 species. Of these, 43% are new records for the region of Cusco, 15 species are new records for the Peruvian flora, 40 species are endemics for Peru, and 30 are potential new species for science. Another 39.7% are identified to genus or family level and remain morphospecies. Additionally, we show altitudinal range expansion for 45.2% of identified species (302 species. These results were found in a transect of plots spanning only 20 km of geographic distance, and are a sample of the high tree diversity in these mountainous ecosystems. The data show how poorly collected and understudied these ecosystems are. Basic floristic studies and collections are imperative for a better understanding of species distribution and function of ecosystems, and the basic biodiversity of the tropical Andes. They will also help to answer a major, unresolved question in modern global ecology of how tropical forests will respond to global climate change.

  16. Water relations and gas exchange of fan bryophytes and their adaptations to microhabitats in an Asian subtropical montane cloud forest.

    Science.gov (United States)

    Song, Liang; Zhang, Yong-Jiang; Chen, Xi; Li, Su; Lu, Hua-Zheng; Wu, Chuan-Sheng; Tan, Zheng-Hong; Liu, Wen-Yao; Shi, Xian-Meng

    2015-07-01

    Fan life forms are bryophytes with shoots rising from vertical substratum that branch repeatedly in the horizontal plane to form flattened photosynthetic surfaces, which are well suited for intercepting water from moving air. However, detailed water relations, gas exchange characteristics of fan bryophytes and their adaptations to particular microhabitats remain poorly understood. In this study, we measured and analyzed microclimatic data, as well as water release curves, pressure-volume relationships and photosynthetic water and light response curves for three common fan bryophytes in an Asian subtropical montane cloud forest (SMCF). Results demonstrate high relative humidity but low light levels and temperatures in the understory, and a strong effect of fog on water availability for bryophytes in the SMCF. The facts that fan bryophytes in dry air lose most of their free water within 1 h, and a strong dependence of net photosynthesis rates on water content, imply that the transition from a hydrated, photosynthetically active state to a dry, inactive state is rapid. In addition, fan bryophytes developed relatively high cell wall elasticity and the osmoregulatory capacity to tolerate desiccation. These fan bryophytes had low light saturation and compensation point of photosynthesis, indicating shade tolerance. It is likely that fan bryophytes can flourish on tree trunks in the SMCF because of substantial annual precipitation, average relative humidity, and frequent and persistent fog, which can provide continual water sources for them to intercept. Nevertheless, the low water retention capacity and strong dependence of net photosynthesis on water content of fan bryophytes indicate a high risk of unbalanced carbon budget if the frequency and severity of drought increase in the future as predicted.

  17. Life in the Treetops: Drought Tolerance and Water Balance of Canopy Epiphytes in a Tropical Montane Cloud Forest

    Science.gov (United States)

    Gotsch, S. G.; Nadkarni, N.; Darby, A.; Dix, M.; Glunk, A.; Davidson, K.; Dawson, T. E.

    2014-12-01

    Tropical montane cloud forests (TMCFs) inhabit regions rich in biodiversity that play an important role in the local and regional water cycle. Canopy plants such as epiphytes and hemiepiphytes are an important component of the biodiversity in the TMCF and therefore play a significant role in the carbon, nutrient and water cycles. With only partial or no access to resources on the ground, canopy plants may be vulnerable to changes in climate that increase canopy temperatures and decrease atmospheric humidity or precipitation inputs. Despite their importance in the TMCF, there is little information regarding drought tolerance and water balance in this community. In this study we quantified variation in functional traits and water relations in 12 species of epiphytes and hemiepiphytes in a Costa Rican TMCF. We also generated pressure-volume curves and xylem vulnerability curves that we used as indicators of drought tolerance. Lastly, we determined the capacity for foliar water uptake in the laboratory and measured whole-plant transpiration in the field. We found that all species had a high turgor loss point (ψTLP), high vulnerability to cavitation (P50), and low bulk elastic modulus (ɛmax, i.e. high cell wall elasticity). These results indicate that capacitance may be high in canopy plants and that stored water may help to maintain high leaf water potentials during dry periods. We also found that all species had the capacity for foliar uptake and that this process contributed substantially to their water status and water balance. On average, foliar uptake contributed to the reabsorption of 70% of the water transpired over a 34-day period at the beginning of the dry season. Our results indicate that canopy plants can mitigate water loss substantially, but they may be vulnerable to changes in the overall precipitation patterns or increases in cloud base heights.

  18. [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%.

  19. Development of a Compatible Taper Function and Stand-Level Merchantable Volume Model for Chinese Fir Plantations.

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    Xiaolu Tang

    Full Text Available Chinese fir (Cunninghamia lanceolata [Lamb.] Hook is one of the most important plantation tree species in China with good timber quality and fast growth. It covers an area of 8.54 million hectare, which corresponds to 21% of the total plantation area and 32% of total plantation volume in China. With the increasing market demand, an accurate estimation and prediction of merchantable volume at tree- and stand-level is becoming important for plantation owners. Although there are many studies on the total tree volume estimation from allometric models, these allometric models cannot predict tree- and stand-level merchantable volume at any merchantable height, and the stand-level merchantable volume model was not seen yet in Chinese fir plantations. This study aimed to develop (1 a compatible taper function for tree-level merchantable volume estimation, and (2 a stand-level merchantable volume model for Chinese fir plantations. This "taper function system" consisted in a taper function, a merchantable volume equation and a total tree volume equation. 46 Chinese fir trees were felled to develop the taper function in Shitai County, Anhui province, China. A second-order continuous autoregressive error structure corrected the inherent serial autocorrelation of different observations in one tree. The taper function and volume equations were fitted simultaneously after autocorrelation correction. The compatible taper function fitted well to our data and had very good performances in diameter and total tree volume prediction. The stand-level merchantable volume equation based on the ratio approach was developed using basal area, dominant height, quadratic mean diameter and top diameter (ranging from 0 to 30 cm as independent variables. At last, a total stand-level volume table using stand basal area and dominant height as variables was proposed for local forest managers to simplify the stand volume estimation.

  20. Depletion of chlorine into HCl ice in a protostellar core. The CHESS spectral survey of OMC-2 FIR 4

    Science.gov (United States)

    Kama, M.; Caux, E.; López-Sepulcre, A.; Wakelam, V.; Dominik, C.; Ceccarelli, C.; Lanza, M.; Lique, F.; Ochsendorf, B. B.; Lis, D. C.; Caballero, R. N.; Tielens, A. G. G. M.

    2015-02-01

    Context. The freezeout of gas-phase species onto cold dust grains can drastically alter the chemistry and the heating-cooling balance of protostellar material. In contrast to well-known species such as carbon monoxide (CO), the freezeout of various carriers of elements with abundances OMC-2 FIR 4. Methods: We observed transitions of HCl and H2Cl+ towards OMC-2 FIR 4 using the Herschel Space Observatory and Caltech Submillimeter Observatory facilities. Our analysis makes use of state of the art chlorine gas-grain chemical models and newly calculated HCl-H2 hyperfine collisional excitation rate coefficients. Results: A narrow emission component in the HCl lines traces the extended envelope, and a broad one traces a more compact central region. The gas-phase HCl abundance in FIR 4 is 9 × 10-11, a factor of only 10-3 that of volatile elemental chlorine. The H2Cl+ lines are detected in absorption and trace a tenuous foreground cloud, where we find no depletion of volatile chlorine. Conclusions: Gas-phase HCl is the tip of the chlorine iceberg in protostellar cores. Using a gas-grain chemical model, we show that the hydrogenation of atomic chlorine on grain surfaces in the dark cloud stage sequesters at least 90% of the volatile chlorine into HCl ice, where it remains in the protostellar stage. About 10% of chlorine is in gaseous atomic form. Gas-phase HCl is a minor, but diagnostically key reservoir, with an abundance of ≲10-10 in most of the protostellar core. We find the [35Cl]/[37Cl] ratio in OMC-2 FIR 4 to be 3.2 ± 0.1, consistent with the solar system value. Appendices are available in electronic form at http://www.aanda.org