647 research outputs found
Jacobs, Henry (Death, 1899-01-15)
No full textAddress: S. W. Cor. Allison & Main St.Age at death: 47 yrs.Pg 8/1899/393/M W M/Germany/Dr. J. Bollander/Unnewehr & Siebem/Walnut HillsOriginal record filed in drawer labeled 'Irving-Jamesom'
Optical instruments for measuring leaf area index in low vegetation : application in Arctic ecosystems
No full textAuthor Posting. © Ecological Society of America, 2005. This article is posted here by permission of Ecological Society of America for personal use, not for redistribution. The definitive version was published in Ecological Applications 15 (2005): 1462–1470, doi:10.1890/03-5354.Leaf area index (LAI) is a powerful diagnostic of plant productivity. Despite the fact that many methods have been developed to quantify LAI, both directly and indirectly, leaf area index remains difficult to quantify accurately, owing to large spatial and temporal variability. The gap-fraction technique is widely used to estimate the LAI indirectly. However, for low-stature vegetation, the gap-fraction sensor either cannot get totally underneath the plant canopy, thereby missing part of the leaf area present, or is too close to the individual leaves of the canopy, which leads to a large distortion of the LAI estimate. We set out to develop a methodology for easy and accurate nondestructive assessment of the variability of LAI in low-stature vegetation. We developed and tested the methodology in an arctic landscape close to Abisko, Sweden.
The LAI of arctic vegetation could be estimated accurately and rapidly by combining field measurements of canopy reflectance (NDVI) and light penetration through the canopy (gap-fraction analysis using a LI-COR LAI-2000). By combining the two methodologies, the limitations of each could be circumvented, and a significantly increased accuracy of the LAI estimates was obtained. The combination of an NDVI sensor for sparser vegetation and a LAI-2000 for denser vegetation could explain 81% of the variance of LAI measured by destructive harvest. We used the method to quantify the spatial variability and the associated uncertainty of leaf area index in a small catchment area.This research was funded by U.S. National Science Foundation
grant DEB0087046
What role does the right side of the heart play in circulation?
No full textRight ventricular failure (RVF) is an underestimated problem in intensive care. This review explores the physiology and pathophysiology of right ventricular function and the pulmonary circulation. When RVF is secondary to an acute increase in afterload, the picture is one of acute cor pulmonale, as occurs in the context of acute respiratory distress syndrome, pulmonary embolism and sepsis. RVF can also be caused by right myocardial dysfunction. Pulmonary arterial catheterization and echocardiography are discussed in terms of their roles in diagnosis and treatment. Treatments include options to reduce right ventricular afterload, specific pulmonary vasodilators and inotropes
Resilience to large-scale disturbance in coral and fish assemblages on the Great Barrier Reef
No full textRecognition of the complex spatial and temporal variability of abundance and diversity found in many populations has led to a greater focus on the roles of heterogeneity, stochasticity, and disturbance in the structure and persistence of communities. This focus is directly relevant to coral reef communities that are characterized by very high species diversity in a spatially heterogeneous environment, display stochastic variability in community structure at small spatial and temporal scales, and are subject to major disturbances. We monitored coral and fish assemblages over 14 years on fixed sites spread over 80 km of the southern Great Barrier Reef (GBR), Australia, and found evidence of large-scale resilience and predictable recovery of these assemblages. Sometime between November 1987 and October 1989, live coral cover on the shallow northeast flanks of some reefs in the southern GBR decreased from >80% to <10%, probably as a result of storm damage. We compared the fish and benthic communities present in these areas prior to the disturbance (1983-1984) with those present in 1992 and the subsequent changes through to 1998. Hard coral cover increased slowly from 1992 to 1994, then accelerated to be indistinguishable from pre-impact levels by 1998. The response of the coral assemblages was largely due to the predominance of tabulate Acropora species and their characteristics of rapid growth and competitive dominance. Patterns of species richness of the fish families Acanthuridae, Chaetodontidae, Scaridae, and Pomacentridae mirrored that of hard coral, except the Pomacentridae had not recovered to pre-impact levels by 1998. Of the 26 fish species analyzed for changes in abundance, 88% decreased after the disturbance, then subsequently increased, with all but two recovering to pre-impact levels by 1998. Although processes such as settlement and immigration are ultimately responsible for replenishment of local populations, our data suggested that habitat plays a strong role in modifying fish assemblages. Thus, both coral and fish assemblages demonstrated resilience to large-scale natural disturbance and predictability in the structure of the assemblages, with most taxa approaching the asymptote of abundance and species richness that existed prior to the disturbance.PT: J; CR: ALLEN GR, 1998, GUIDE ANGELFISHES BU AULT TR, 1998, ECOL MONOGR, V68, P25 BAIRD AH, 2000, J EXP MAR BIOL ECOL, V251, P117 BELL JD, 1984, MAR ECOL-PROG SER, V15, P265 BOHNSACK JA, 1983, ENVIRON BIOL FISH, V9, P41 BORMANN FH, 1979, AM SCI, V67, P660 BROTHERS EB, 1983, MAR BIOL, V76, P319 BROWN BE, 1997, CORAL REEFS, V16, P129 BUDDEMEIER RW, 2002, CORAL REEFS, V21, P1 BYTHELL JC, 2000, MAR ECOL-PROG SER, V204, P93 CALEY MJ, 1996, J ANIM ECOL, V65, P414 CHABANET P, 1997, CORAL REEFS, V16, P93 CHEAL AJ, 2002, CORAL REEFS, V21, P131 CHESSON PL, 1986, COMMUNITY ECOLOGY, P229 CHOAT JH, 1996, MAR ECOL-PROG SER, V134, P15 CLEY MJ, 1997, P 8 INT COR REEF S, V1, P993 COLGAN MW, 1987, ECOLOGY, V68, P1592 CONNELL JH, 1978, SCIENCE, V199, P1302 CONNELL JH, 1983, AM NAT, V121, P789 CONNELL JH, 1997, CORAL REEFS S, V16, P101 CONNELL JH, 1997, ECOL MONOGR, V67, P461 CORNELL HV, 1996, J ANIM ECOL, V65, P233 DAVIES PJ, 1979, SEARCH, V10, P776 DAVIES PJ, 1980, NATURE, V287, P37 DOHERTY PJ, 1987, B MAR SCI, V41, P411 DOHERTY PJ, 1991, ECOLOGY FISHES CORAL, P261 DOHERTY PJ, 1997, P 8 INT COR REEF S P, V1, P1005 DONE TJ, 1992, CONT SHELF RES, V12, P859 FOWLER AJ, 1990, MAR ECOL-PROG SER, V64, P39 FOWLER AJ, 1992, MAR ECOL-PROG SER, V82, P131 FRIEDLANDER AM, 1998, J EXP MAR BIOL ECOL, V224, P1 GREEN AL, 1996, MAR ECOL-PROG SER, V133, P1 HANSKI I, 1998, NATURE, V396, P41 HART AM, 1996, MAR ECOL-PROG SER, V132, P11 HART AM, 1996, MAR ECOL-PROG SER, V132, P21 HEINSELMAN ML, 1981, P C FIR REG EC PROP, P7 HIXON MA, 1991, ECOLOGY FISHES CORAL, P475 HIXON MA, 1993, ECOL MONOGR, V63, P77 HOBBS RJ, 1994, PACIFIC CONSERVATION, V1, P170 HOLLING CS, 1973, ANNUAL REV ECOLOGY S, V4, P1 HUGHES TP, 1994, SCIENCE, V265, P1547 HUGHES TP, 1999, LIMNOL OCEANOGR 2, V44, P932 JONES GP, 1991, ECOLOGY FISHES CORAL, P294 JONES GP, 1998, AUST J ECOL, V23, P287 KARLSON RH, 1993, CORAL REEFS, V12, P117 LASSIG BR, 1983, ENVIRON BIOL FISH, V9, P55 LEWIS AR, 1997, MAR ECOL-PROG SER, V161, P37 LITTELL RC, 1996, SAS SYSTEM MIXED MOD LUCKHURST BE, 1978, MAR BIOL, V49, P317 MASSEL SR, 1993, CORAL REEFS, V12, P153 MCCULLAGH P, 1989, GENERALIZED LINEAR MEEKAN MG, 1999, B MAR SCI, V64, P383 NINIO R, 2000, MAR ECOL-PROG SER, V194, P65 NINIO R, 2002, CORAL REEFS, V21, P95 NOTT J, 2001, NATURE, V413, P508 ODUM EP, 1969, SCIENCE, V164, P262 OLIVER JK, 1995, LONG TERM MINITORING PAINE RT, 1981, ECOL MONOGR, V51, P145 PICKETT STA, 1986, ECOLOGY NATURAL DIST PIUMM SL, 1991, BALANCE NATURE ECOL RANDALL JE, 1990, FISHES GRET BARRIER ROBERTS CM, 1987, MAR ECOL-PROG SER, V41, P1 SALE PF, 1978, ENVIRON BIOL FISH, V3, P85 SALE PF, 1982, AM NAT, V120, P121 SANO M, 2000, MAR ECOL-PROG SER, V198, P121 STIMSON J, 1985, ECOLOGY, V66, P40 SWEATMAN H, 2000, 4 I MAR SCI SWEATMAN H, 2001, 5 AUSTR I MAR SCI SYMS C, 1998, J EXP MAR BIOL ECOL, V230, P151 SYMS C, 2000, ECOLOGY, V81, P2714 THOMPSON AA, 2002, MAR ECOL-PROG SER, V232, P247 VANWOESIK R, 1991, J COASTAL RES, V7, P551 WALSH WJ, 1983, CORAL REEFS, V2, P49 WELLINGTON GM, 1985, OECOLOGIA, V68, P15 WILKINSON CR, 1999, MAR FRESHWATER RES, V50, P867 WILLIAMS DM, 1982, CORAL REEFS, V1, P35 WILLIAMS DM, 1983, MAR ECOL-PROG SER, V10, P239 WILLIAMS DM, 1986, MAR ECOL-PROG SER, V28, P157 WILLIAMS DM, 1991, ECOLOGY FISHES CORAL, P437 WOODLEY JD, 1981, SCIENCE, V214, P749 WU JG, 1995, Q REV BIOL, V70, P439; NR: 81; TC: 9; J9: ECOLOGY; PG: 14; GA: 843VASource type: Electronic(1
Transcription factors involved in cold response in plants.
No full textStudies in Arabidopsis have shown cold stress tolerance can be enhanced by manipulation of the CBF/DREB and ICE transcription factor genes. To date, few studies have investigated CBF and ICE genes in crops species such as barley. Using a C-repeat element as bait, two CBF genes were isolated from a cold-stressed barley cDNA library, HvCBF16 and HvCBF23. HvCBF16 was induced by cold treatment but not by other abiotic stresses. HvCBF23 was constitutively expressed and was not induced by cold treatment. The analysis of transgenic plants expressing these genes will determine their importance in cold tolerance.
Transgenic barley plants expressing the barley gene HvCBF2A were found to be more cold tolerant in controlled temperature trials, and hence were assayed to determine the basis of their acquired phenotype. Northern and qRT-PCR analysis showed that four genes known to be involved in cold tolerance were significantly upregulated. Importantly the increased expression was proportional to the level of transgene expression and levels were higher following cold treatment.
A homolog of the Arabidopsis ICE transcription factor was isolated from a freezing-tolerant barley variety (Hordeum vulgare L. cv. Haruna Nijo) and transcript analysis of HvICE2 under various abiotic stresses showed that expression of HvICE2 was induced at low temperatures, particularly in floral tissues. HvICE2 was over-expressed using the maize ubiquitin constitutive promoter in transgenic barley. Expression analysis of putative downstream genes, including various COR genes, in the transgenic plants before and during cold treatment did not reveal any alteration in expression. This suggests HvICE2 that the COR genes studied are not targets of HvICE2 or that additional factors or conditions are required for effective function of HvICE2. Transgenic Arabidopsis plants were produced with over- or reduced-expression of the uncharacterised ICE gene, AtICE2. The cold tolerance of the AtICE2 transgenic lines was not significantly different from wild type plants.Thesis (Ph.D.) -- University of Adelaide, School of Agriculture, Food and Wine, 201
Source partitioning of H2O and CO2 fluxes based on high-frequency eddy covariance data: a comparison between study sites
No full textFor an assessment of the roles of soil and vegetation in the climate system, a further understanding of the fluxcomponents of H2O and CO2 (e.g., transpiration, soil respiration) and their interaction with physical conditions andphysiological functioning of plants and ecosystems is necessary. To obtain magnitudes of these flux components, we appliedsource partitioning approaches after Scanlon and Kustas (2010; SK10) and after Thomas et al. (2008; TH08) tohigh-frequency eddy covariance measurements of 12 study sites covering different ecosystems (croplands, grasslands,and forests) in different climatic regions. Both partitioning methods are based on higher-order statistics of the H2O andCO2 fluctuations, but proceed differently to estimate transpiration, evaporation, net primary production, and soil respiration.We compared and evaluated the partitioning results obtained with SK10 and TH08, including slight modificationsof both approaches. Further, we analyzed the interrelations among the performance of the partitioning methods, turbulencecharacteristics, and site characteristics (such as plant cover type, canopy height, canopy density, and measurement height).We were able to identify characteristics of a data set that are prerequisites for adequate performance of the partitioningmethods.\\SK10 had the tendency to overestimate and TH08 to underestimate soil flux components. For both methods, the partitioningof CO2 fluxes was less robust than for H2O fluxes. Results derived with SK10 showed relatively large dependencieson estimated water use efficiency (WUE) at the leaf level, which is a required input. Measurements of outgoinglongwave radiation used for the estimation of foliage temperature (used in WUE) could slightly increase the qualityof the partitioning results. A modification of the TH08 approach, by applying a cluster analysis for the conditionalsampling of respiration–evaporation events, performed satisfactorily, but did not result in significant advantages comparedto the original method versions developed by Thomas et al. (2008). The performance of each partitioning approachwas dependent on meteorological conditions, plant development, canopy height, canopy density, and measurementheight. Foremost, the performance of SK10 correlated negatively with the ratio between measurement height and canopyheight. The performance of TH08 was more dependent on canopy height and leaf area index. In general, all site characteristicsthat increase dissimilarities between scalars appeared to enhance partitioning performance for SK10 and TH08
American and European Mix Design Approaches Combined: Use of NCHRP Performance Indicators to Analyze Comité Européen de Normalisation Test Results
No full textThis paper describes a project that is part of NL-LAB, a larger, long-term program at Delft University of Technology, Netherlands, which aims to establish the predictive capacity of the current European functional tests for Dutch asphalt concrete (AC) mixtures. In this NL-LAB program, the functional characteristics of resistance to rutting (EN 12697-25), fatigue (EN 12679-24), stiffness (EN 12697-26), and moisture sensitivity (EN 12697-12 and EN 12697-23) are determined for specimens that are (a) mixed and compacted in the lab, (b) mixed in the plant and compacted in the lab, and (c) mixed in the plant and compacted in the road. Eventually, these tests will provide insight into the effect of mixing and compaction on the functional characteristics. The project described in this paper focused on the indirect tensile strength (ITS) and the triaxial cyclic compression test for two AC mixes. The properties found for all three stages of preparation were analyzed with the use of formalistic expressions from the NCHRP Design Guide 1-37A, Level 2, for the estimation of performance indicators. This project aimed to see if these relations remained valid for the Comité Européen de Normalisation tests, especially for mixes with high recycled asphalt pavement content. In the Netherlands, 50% reclaimed asphalt pavement is standard. It was found that the NCHRP Design Guide 1-37A expressions fit the Comité Européen de Normalisation test data quite well for the reclaimed asphalt pavement that contained mixes, especially for the ITS. Currently, another two construction projects are being sampled, and the results will be used to validate and improve the relations
Obliteração pulpar em incisivo decíduo traumatizado
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências da Saúde. Programa de Pós-Graduação em Odontologia.Este estudo descritivo retrospectivo em incisivos centrais superiores decíduos traumatizados teve por objetivo, verificar a ocorrência de obliteração pulpar, o tempo decorrido entre o trauma e o desenvolvimento desta seqüela, a presença de alteração de cor da coroa bem como a freqüência de necrose pulpar secundária nos dentes obliterados, além de avaliar a existência de associação entre a obliteração e o sexo, a idade do paciente no momento do trauma dental, o tipo e a reincidência de trauma. Para isto, realizou-se uma pesquisa desenvolvida a partir dos dados clínicos e radiográficos dos prontuários de pacientes participantes do Programa de Atendimento ao Paciente Traumatizado da Universidade Federal de Santa Catarina, entre agosto de 1998 e agosto de 2007. Seguindo os critérios de elegibilidade, foram incluídos 112 dentes de 82 crianças. Destes, 60 (53,6%) apresentavam obliteração pulpar, sendo que em 58,3% dos casos esta foi diagnosticada em até 12 meses após o trauma. A associação entre alteração de cor da coroa e obliteração pulpar foi confirmada (p<0,001), e não houve casos de necrose pulpar secundária. Não se observou associação estatística entre as variáveis sexo e idade dos pacientes, bem como tipo e recorrência de trauma em relação a obliteração pulpar. Os resultados deste estudo permitem concluir que a ocorrência de obliteração pulpar em dentes decíduos traumatizados é alta e a proservação clínica e radiográfica periódica é a melhor conduta para esta seqüela
Kroon de boom tot airco van de stad : Verkoeling door groen en beplanting gemodelleerd
No full textDit artikel sluit aan op de publicatie over droogteschade bij stadsbomen in het vorige nummer van het vakblad (Bomen 53). Vijf studenten aan Hogeschool Van Hall Larenstein (VHL) hebben in 2019/2020 als onderdeel van de minor ‘Bomen en Stedelijke Omgeving’ onderzoek uitgevoerd naar het effect van groen/beplanting op de gevoelstemperatuur in ‘bloemkoolwijken’. De opdrachtgever voor dit onderzoek was dr. ir. Jelle Hiemstra van Wageningen University & Research. Op het gebied van ENVI-met kregen zij begeleiding van dr. ir. Cor Jacobs van Wageningen University & Research, die hen hielp met het bouwen van het model en het berekenen van de temperatuur, luchtvochtigheid, windstromen en gevoelstemperatuur. De studenten werden begeleid door docent dr. Mart Vlam. Onderstaand verslag van dit onderzoek is geschreven op basis van vragen die ex-redactielid Jozé ’t Hoen en redactielid Jaco Houweling de studenten hebben voorgelegd
Comparação de métodos pata medição de absortância solar em elementos opacos
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia Civil, Florianópolis, 2012A radiação solar é um dos fatores que mais contribui para o ganho térmico em edificações, principalmente em regiões tropicais e de baixas latitudes, como é o caso do Brasil. As trocas de energia (luz e calor) entre os meios exterior e interior das edificações dependerão, fundamentalmente, da envoltória construtiva e de suas propriedades termo-físicas, em especial a propriedade de absortância para os componentes opacos. A absortância dos componentes opacos da envoltória construtiva determinam parte do impacto da radiação solar na edificação, pois indicam qual fração da energia solar que chega à edificação será absorvida por seu envelope, afetando seu ganho de calor e as temperaturas internas. A falta de dados atualizados de absortância solar para superfícies opacas faz com que pesquisadores e especialistas utilizem a percepção visual ou valores estimados de absortância, acarretando em uma escolha muitas vezes equivocada sobre a cor da envoltória, que pode causar uma cor com alta absortância e baixa eficiência energética por parte da envoltória. Neste sentido, o valor da absortância das superfícies externas do edifício deve ser o mais preciso possível e quando feita a análise da absortância desses materiais na própria edificação é de suma importância que seja usado o instrumento correto para as características da envoltória. Este trabalho apresenta uma proposta para obtenção de dados de absortância solar de superfícies opacas, verificando métodos utilizados para análise absortiva de materiais opacos, avaliando a viabilidade de cada um desses métodos em função das diferentes texturas de materiais rugosos. Para comprovar a aplicabilidade dos métodos propostos serão realizados estudos com quatro instrumentos de medição para diferentes níveis de texturas de superfícies opacas, verificando os efeitos da rugosidade sobre a absortância dessas superfícies. Os métodos baseiam-se em medições realizadas com uma bancada (com monocromador e uma esfera integradora), um espectrômetro portátil Alta II, um Luxímetro digital e um Luminancímetro. O trabalho também contribui com valores de absortâncias solares de tintas para a construção de um banco de dados referente às tintas disponíveis comercialmente no Brasil Abstract: Solar radiation is one of many factors that contribute in gain heat of buildings, mainly in tropical regions and low latitudes, which is the case of Brazil. The changes of energy (heat and light) between outer and internal buildings depend mainly on the envelope constructive and thermo physical properties, specially the absorbance for opaque components. The absorbance of opaque components of constructive envelope determine a portion of the impact of solar radiation in the building, they indicate what fraction of solar energy that reaches the construction will be absorbed by the envelope, affecting your heat gain and internal temperatures. The lack of update data of solar absorbance for opaque surfaces makes researchers and specialists use visual perception or estimated values of absorbance, resulting in a choice often mistaken about the color of the envelope, which can cause a color with high absorbance and law energy efficiency on the part of the envelope. In this sense, the absorbance value of the building´s external surfaces has to be as accurate as possible, and when doing the absorbance analysis of these materials in the building itself it is very important that the right instrument is utilized given the characteristics of the envelope.This paper presents a proposal for obtaining data from solar absorbance of opaque surfaces, checking absorptive methods used for analysis of opaque materials, assessing the viability of each of these methods according to the different textures of rough materials. To prove the applicability of the proposed methods, studies with four measuring instruments for different levels of textures on opaque surfaces will be conducted, verifying the effects of roughness on the absorbance of these surfaces. These methods are based on measurements made by the bank (monochromator and a sphere of integration), one portable spectrometer high II, a digital Luximeter and a luminancemeter. This work also contributes with the values of solar absorbance for paints with the proposed of building a database concerning paints commercially available in Brazil
- …
