1,063 research outputs found

    Remote sensing of the seasonal variation of coniferous forest structure and function

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    One of the objectives of the Oregon Transect Ecosystem Research (OTTER) project is the remotely sensed determination of the seasonal variation of leaf area index (LAI) and absorbed photosynthetically active radiation (APAR). These measurements are required for input into a forest ecosystem model which predicts net primary production evapotranspiration, and photosynthesis of coniferous forests. Details of the study are given

    The Influence Of The Circadian Clock On Stomal Conductance And Carbon Assimilation In Arabidopsis thaliana

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    Plants have evolved an internal feedback system of gene expression, the circadian clock, to allow for adaptations to changes in diurnal conditions to maximise their ability to utilise the environment for nutrients and growth. The circadian clock aligns the plants processes with fixed external signals, such as the light intensities at dawn and dusk. This study investigated the influence of the circadian clock on stomatal conductance and carbon assimilation and the decoupling of these processes. Timing of Cab (TOC1) and Circadian Clock Associated 1 (CCA1) genes were overexpressed and tested to investigate the impact of altered clock rhythms. Evidence showed of significant increases in carbon assimilation for the TOC1 overexpressed genotype compared to the CCA1 overexpressed genotypes. Data also showed the TOC1 overexpressed genotype had a lower Water Use Efficiency (WUE) than any of the other genotypes, signifying a potential weakening of stomatal sensitivity to internal water levels and allowing for increased photosynthesis at the detriment of water conservation. Changes to light conditions were investigated to look at any corresponding impact on the decoupling of processes when the plant would not be able to correctly align itself to dawn. Changes in light regimes were shown to increase the extent of the decoupling between stomatal conductance with carbon assimilation. Shifting the timings of dawn 2 hours behind “natural dawn” were shown to impact the size but not the timing of the decoupling in relation to the initial increase in light intensity. Overall, this study suggests that the circadian clock is not the cause of the decoupling between these processes but does have an impact on the size of the difference between these process that were thought closely linked

    High Resolution Spectrometry of Leaf and Canopy Chemistry for Biochemical Cycling

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    High-resolution laboratory spectrophotometer and Airborne Imaging Spectrometer (AIS) data were used to analyze forest leaf and canopy chemistry. Fundamental stretching frequencies of organic bonds in the visible, near infrared and short-wave infrared are indicative of concentrations and total content of nitrogen, phosphorous, starch and sugar. Laboratory spectrophotometer measurements showed very strong negative correlations with nitrogen (measured using wet chemistry) in the visible wavelengths. Strong correlations with green wet canopy weight in the atmospheric water absorption windows were observed in the AIS data. A fairly strong negative correlation between the AIS data at 1500 nm and total nitrogen and nitrogen concentration was evident. This relationship corresponds very closely to protein absorption features near 1500 nm

    In Re R.R.N.: Redefining Caretaker for North Carolina Child Protective Services

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    In 2015, the North Carolina Supreme Court interpreted for the first time the definition of caretaker as provided in the State\u27s Juvenile Code. The court narrowed the definition, providing that the statutory language an adult relative entrusted with the juvenile\u27s care means an adult relative who has a significant degree of parental-type responsibility for the child. The court\u27s interpretation has made caretaker equivalent to in loco parentis, which results in a heightened standard that likely was not intended by the legislature. This Comment discusses the far-reaching effects of the court\u27s decision on North Carolina\u27s child welfare services, law enforcement, and practitioners who represent or interact with these agencies. This Comment also explores solutions to bridge the widening gap in service provision to the families and children of North Carolina

    the Straight Furrow\u27: The Life Of George S Henry, Ontario\u27s Unknown Premier

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    The life of George S. Henry and his management of the Ontario economy as Conservative premier (1930-1934) has been unjustifiably ignored by academics. Henry\u27s unique upbringing --his Methodist canons of individualism, his Pelmanist notions of efficiency, and his obsession with economic development--would shape his career throughout the 1920s when, as Highways minister, he brought uniformity and standardization to the province\u27s complex road system. As premier, these principles and values would also have a significant impact upon how Ontario was governed in the early depression years.;Throughout Henry\u27s premiership, his government\u27s austere attitude towards unemployment was determined by three factors: a faith in recovery; public and financial pressures for economy; and, most importantly, the government\u27s fear of further credit instability based upon its difficult experience in early 1932. Ontario\u27s economic position during the early depression years was far more precarious than historians have assumed. Government relief policy was more sensitive to the majority--the overburdened taxpayers and their demands for less government--than those who were in actual need. This climate of opinion was reflected in Henry\u27s policies, many of which have left an indelible mark upon his province: his attempt to centralize and regulate unemployment relief administration, his imposed standardization and centralization of government services, his establishment of the Ontario Municipal Board and its ensuing provincial control over municipal finances, and his creation of agricultural marketing boards to improve Ontario\u27s exports.;Nonetheless, Henry\u27s unusual approach to politics won few admirers. More of an administrator than a politician, Henry was determined that Ontario\u27s infrastructure of highway and hydro-electric development--particularly the gains made in the 1920s--should not be allowed to unravel. Accordingly, his concern for the province\u27s long-term economic development took pride of place over short-term political gain. As manifested in his unpopular policies of economic retrenchment and electoral redistribution, Henry\u27s penchant for efficiency in public service and his corresponding disdain for politics was a source of great disunity and dissent within the Ontario Conservative Party--one that would lead ultimately to defeat at the hands of Mitchell Hepburn\u27s Liberals in 1934

    Verfassungsfragen der Finanzplanung

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    Switched wave packets: A route to nonperturbative quantum control

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    The dynamic Stark effect due to a strong nonresonant but nonionizing laser field provides a route to quantum control via the creation of novel superposition states. We consider the creation of a field-free "switched" wave packet through adiabatic turn-on and sudden turn-off of a strong dynamic Stark interaction. There are two limiting cases for such wave packets. The first is a Raman-type coupling, illustrated by the creation of field-free molecular axis alignment. An experimental demonstration is given. The second case is that of dipole-type coupling, illustrated by the creation of charge localization in an array of quantum wells

    Photoelectron spectra in strong-field ionization by a high frequency field

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    We analyze atomic photoelectron momentum distributions induced by bichromatic and monochromatic laser fields within the strong field approximation (SFA), separable Coulomb-Volkov approximation (SCVA), and ab initio treatment. We focus on the high frequency regime -- the smallest frequency used is larger than the ionization potential of the atom. We observe a remarkable agreement between the ab initio and velocity gauge SFA results while the velocity gauge SCVA fails to agree. Reasons of such a failure are discussed.Comment: Completely rewritten paper. Ionization by a two-color field is adde

    Space-resolved dynamics of a tracer in a disordered solid

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    The dynamics of a tracer particle in a glassy matrix of obstacles displays slow complex transport as the free volume approaches a critical value and the void space falls apart. We investigate the emerging subdiffusive motion of the test particle by extensive molecular dynamics simulations and characterize the spatio-temporal transport in terms of two-time correlation functions, including the time-dependent diffusion coefficient as well as the wavenumber-dependent intermediate scattering function. We rationalize our findings within the framework of critical phenomena and compare our data to a dynamic scaling theory.Comment: 10 pages, 7 figures, submitted to Journal of Non-Crystalline Solid
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