110 research outputs found

    Combining MODIS LAI with ICESat-Based Canopy Heights Improves Spaceborne Estimates of Vegetation Roughness Length for Momentum

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    Most land-surface models require parameterization of vertical wind profiles within the atmospheric boundary layer. For vegetated surfaces, it is common to assume a logarithmic profile in the surface layer, which includes estimates of vegetation roughness length for momentum (z0) and zero-plane displacement height (d0). This study finds that remotely-sensed forest canopy heights improve estimates of aerodynamic roughness length for momentum using a previously-developed representation of the roughness sublayer (Raupach 1992; Jasinski et al. 2005). Resulting roughness products consist of two datasets: 1) 14 years of 8-day snapshots of the global land surface at a nominal spatial resolution of 500-meters for users who wish to retain full temporal resolution and interannual variability; and 2) multiyear averages of the 8-day snapshots, here referred to as "climatologies" of roughness, which retain underlying seasonality. Both products are suitable for use in data assimilation and reanalyses such as the National Climate Assessment Land Data Assimilation System (NCA-LDAS), for which these products were initially developed

    Estimation of Vegetation Aerodynamic Roughness of Natural Regions Using Frontal Area Density Determined from Satellite Imagery

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    Parameterizations of the frontal area index and canopy area index of natural or randomly distributed plants are developed, and applied to the estimation of local aerodynamic roughness using satellite imagery. The formulas are expressed in terms of the subpixel fractional vegetation cover and one non-dimensional geometric parameter that characterizes the plant's shape. Geometrically similar plants and Poisson distributed plant centers are assumed. An appropriate averaging technique to extend satellite pixel-scale estimates to larger scales is provided. ne parameterization is applied to the estimation of aerodynamic roughness using satellite imagery for a 2.3 sq km coniferous portion of the Landes Forest near Lubbon, France, during the 1986 HAPEX-Mobilhy Experiment. The canopy area index is estimated first for each pixel in the scene based on previous estimates of fractional cover obtained using Landsat Thematic Mapper imagery. Next, the results are incorporated into Raupach's (1992, 1994) analytical formulas for momentum roughness and zero-plane displacement height. The estimates compare reasonably well to reference values determined from measurements taken during the experiment and to published literature values. The approach offers the potential for estimating regionally variable, vegetation aerodynamic roughness lengths over natural regions using satellite imagery when there exists only limited knowledge of the vegetated surface

    4-[Bis(4-fluorophenyl)methyl]piperazin-1-ium picrate

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    The title compound {systematic name: 4-[bis(4-fluorophenyl)methyl]piperazin-1-ium 2,4,6-tri­nitro­phenolate}, C17H19F2N2 +·C6H2N3O7 −, is the picrate salt of a piperazine-supported amine bearing a benzhydryl substituent on one of its N atoms. During co-crystallisation, protonation took place on the N atom of the secondary amine functionality. The non-aromatic six-membered heterocycle adopts a chair conformation. In the crystal, N—H⋯O hydrogen bonds as well as C—H⋯O contacts connect the components into a three-dimensional network

    (E)-1-(4,4′′-Difluoro-5′-meth­oxy-1,1′:3′,1′′-terphenyl-4′-yl)-3-(4-methyl­phen­yl)prop-2-en-1-one

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    In the meta-terphenyl fragment of the title mol­ecule, C29H22F2O2, the two fluoro­phenyl rings are twisted from the central benzene ring by 46.72 (6) and 41.70 (6)°, respectively. In the crystal, weak C—H⋯O and C—H⋯F hydrogen bonds link the mol­ecules into layers parallel to the ab plane. The crystal packing exhibits π–π inter­actions, the shortest distance between the centroids of aromatic rings being 3.6364 (7) Å

    (E)-1-(4,4′′-Difluoro-5′-meth­oxy-1,1′:3′,1′′-terphenyl-4′-yl)-3-phenyl­prop-2-en-1-one

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    The title compound, C28H20F2O2, is a polysubstituted terphenyl derivative bearing a Michael system. The C=C double bond is E configured. In the crystal, C—H⋯O and C—H⋯F contacts connect the mol­ecules, forming undulating sheets that lie perpendicular to the crystallographic a axis. The shortest π–π inter­action [centroid–centroid distance = 3.7163 (7) Å] involves the para-fluoro­phenyl ring in the para position to the Michael system, and its symmetry-generated equivalent

    (E)-1-(4,4′′-Difluoro-5′-meth­oxy-1,1′:3′,1′′-terphenyl-4′-yl)-3-(4-nitro­phen­yl)prop-2-en-1-one

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    In the title compound, C28H19F2NO4, a polysubstituted terphenyl derivative bearing a Michael system, the C=C double bond has an E configuration. Two C—H⋯F contacts connect mol­ecules into inversion dimers. In addition, a C–H⋯π as well as a C–F⋯π contact can be identified. The shortest centroid–centroid distance between two aromatic rings is 3.9535 (8) Å, between one of the para-fluoro­benzene rings and its symmetry-generated equivalent

    Cinnarizinium 3,5-dinitro­salicylate

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    The title compound [systematic name: 4-diphenyl­methyl-1-(3-phenylprop-2-en-1-yl)-piperazin-1-ium 2-carb­oxy-4,6-dinitro­pheno­late], C26H29N2 +·C7H3N2O7 −, is the dinitro­salicylate salt of a tertiary amine. Deprotonation of the carb­oxy­lic acid group occurred on the phenolic hy­droxy group. The diaza­cyclo­hexane ring adopts a chair conformation. Intra­molecular O—H⋯O and inter­molecular C—H⋯O and N—H⋯O hydrogen bonds are observed. The N—H⋯O hydrogen bonds are bifurcated at the H atom and connect the cinnarizinium and 3,5-dinitro­salicylate ions together. Inter­molecular C—H⋯O hydrogen bonds connect the components into layers perpendicular to the crystallographic a axis

    (E)-1-(4,4′′-Difluoro-5′-meth­oxy-1,1′:3′,1′′-terphenyl-4′-yl)-3-(4-meth­oxy­phen­yl)prop-2-en-1-one

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    The title compound, C29H22F2O3, is a meta-terphenyl derivative featuring a Michael-system-derived substituent with an E-configured C=C function. In the crystal, C—H⋯O and C—H⋯F contacts connect the mol­ecules into planes parallel to (101). The shortest centroid–centroid distance between two aromatic systems is 3.7169 (7) Å and is apparent between the terminal benzene ring of the Michael-system-derived substituent and its symmetry-generated equivalent

    Opipramol dihydro­chloride

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    The title compound (systematic name: 4-{3-[2-aza­tricyclo­[9.4.0.03,8]penta­deca-1(15),3,5,7,11,13-hexaen-2-yl]prop­yl}-1-(2-hy­droxy­eth­yl)piperazine-1,4-diium dichloride), C23H31N3O+·2Cl−, is the dihydro­chloride of a piperazine derivative bearing a bulky 3-(5H-dibenz[b,f]azepin-5-yl)propyl substituent. Protonation took place on both N atoms of the piperazine unit. The diaza­cyclo­hexane ring adopts a chair conformation. N—H⋯Cl, O—H⋯Cl and C—H⋯Cl hydrogen bonding as well as C—H⋯O contacts connect the components into a three-dimensional network in the crystal. Two C—H⋯π contacts are also observed

    A systematic review of the safety of lisdexamfetamine dimesylate

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    BACKGROUND: Here we review the safety and tolerability profile of lisdexamfetamine dimesylate (LDX), the first long-acting prodrug stimulant for the treatment of attention-deficit/hyperactivity disorder (ADHD). METHODS: A PubMed search was conducted for English-language articles published up to 16 September 2013 using the following search terms: (lisdexamfetamine OR lisdexamphetamine OR SPD489 OR Vyvanse OR Venvanse OR NRP104 NOT review [publication type]). RESULTS: In short-term, parallel-group, placebo-controlled, phase III trials, treatment-emergent adverse events (TEAEs) in children, adolescents, and adults receiving LDX were typical for those reported for stimulants in general. Decreased appetite was reported by 25-39 % of patients and insomnia by 11-19 %. The most frequently reported TEAEs in long-term studies were similar to those reported in the short-term trials. Most TEAEs were mild or moderate in severity. Literature relating to four specific safety concerns associated with stimulant medications was evaluated in detail in patients receiving LDX. Gains in weight, height, and body mass index were smaller in children and adolescents receiving LDX than in placebo controls or untreated norms. Insomnia was a frequently reported TEAE in patients with ADHD of all ages receiving LDX, although the available data indicated no overall worsening of sleep quality in adults. Post-marketing survey data suggest that the rate of non-medical use of LDX was lower than that for short-acting stimulants and lower than or equivalent to long-acting stimulant formulations. Small mean increases were seen in blood pressure and pulse rate in patients receiving LDX. CONCLUSIONS: The safety and tolerability profile of LDX in individuals with ADHD is similar to that of other stimulants
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