Wind Climatology at 87 km above the Rocky Mountains at Bear Lake Observatory--Fabry-Perot Observations of OH

This paper presents the neutral -wind climatology at approximately 87-km 53 altitude from Utah State University\u27s Bear Lake Observatory (BLO). a mid-latitude site 54 situated in the middle of the Rocky Mountains. The winds were determined using a very 55 sensitive Fabry-Perot interferometer (FPI) observing the OH Me inel (6-2) PI (3) line al 56 843 nm. The climatology. determined from monthly averages of the nightly evolution of 57 the geographic meridional and zonal wind components over forty· five months, has three 58 distinct seasonal patterns: winter (November- February), summer (May-Jul y), and late 59 Slimmer (August and September). The background zonal wind is eastward the whole year 60 except March and April. The background meridional wind is northward in winter and 61 southward during the rest of the year. In late summer. the winds exhibit a very strong 62 semidiurnal tidal variation almost every night. In summer, they exhibit a similar tidal 63 variation on enough nights that a semi diurnal pattern appears in the climatology. In 64 winter. the nighHo·night variability is so great that little structure is evident in the 65 climatology . These winds are compared to those from other techniques or sites: ~l 66 observations from UARS. FPI observations from Michigan, and MF radar observations. 67 While generally agreeing in relative amplitudes and i.n phase. differences do exist. 68 especially the weak semidiurnal tide at BLO in winter and a greatly reduced {tide at spring 69 equinox compared to late summer. It is likely that these differences arise from the 2 70 topographical generation of gravity waves by winds flowing over the Rocky Mountains. 71 The tidal variations are also compared to results from the global-scale wave model 72 (GSWM): our semidiurnal amplitudes arc considerably bigger except in winter, and our 73 phases vary from showing very good agreement in July, fair agreement in April and 74 January, and disagreement in October. These large differences may be evidence that 11011 - 75 linear effects are more important than realized. The behavior of the background winds is 76 consistent with different populations of gravity waves reaching 87 km in summer and 77 winter. The behavior of the semidiurnal tidal variation is consistent\u27 with a strong 78 interaction between the tidal and gravity·wave wind fields, and is consistent with the 79 different summer and Winter gravity wave population s, and with a fall· spring asymmetry 80 characterized by much weaker gravity wave sources in late summer than near spring 81 equinox

Hydration of a B-DNA Fragment in the Method of Atom-atom Correlation Functions with the Reference Interaction Site Model Approximation

We propose an efficient numerical algorithm for solving integral equations of the theory of liquids in the Reference Interaction Site Model (RISM) approximation for infinitely dilute solution of macromolecules with a large number of atoms. The algorithm is based on applying the nonstationary iterative methods for solving systems of linear algebraic equations. We calculate the solvent-solute atom-atom correlation functions for a fragment of the B-DNA duplex d(GGGGG).d(CCCCC) in infinitely dilute aqueous solution. The obtained results are compared with available experimental data and results from computer simulations.Comment: 9 pages, RevTeX, 9 pages of ps figures, accepted for publications in JC

Using sonic anemometer temperature to measure sensible heat flux in strong winds

Sonic anemometers simultaneously measure the turbulent fluctuations of vertical wind (<i>w</i>') and sonic temperature (<i>T</i><sub>s</sub>'), and are commonly used to measure sensible heat flux (<i>H</i>). Our study examines 30-min heat fluxes measured with a Campbell Scientific CSAT3 sonic anemometer above a subalpine forest. We compared <i>H</i> calculated with <i>T</i><sub>s</sub> to <i>H</i> calculated with a co-located thermocouple and found that, for horizontal wind speed (<i>U</i>) less than 8 m s<sup>−1</sup>, the agreement was around ±30 W m<sup>−2</sup>. However, for <i>U</i> ≈ 8 m s<sup>−1</sup>, the CSAT <i>H</i> had a generally positive deviation from <i>H</i> calculated with the thermocouple, reaching a maximum difference of ≈250 W m<sup>−2</sup> at <i>U</i> ≈ 18 m s<sup>−1</sup>. With version 4 of the CSAT firmware, we found significant underestimation of the speed of sound and thus <i>T</i><sub>s</sub> in high winds (due to a delayed detection of the sonic pulse), which resulted in the large CSAT heat flux errors. Although this <i>T</i><sub>s</sub> error is qualitatively similar to the well-known fundamental correction for the crosswind component, it is quantitatively different and directly related to the firmware estimation of the pulse arrival time. For a CSAT running version 3 of the firmware, there does not appear to be a significant underestimation of <i>T</i><sub>s</sub>; however, a <i>T</i><sub>s</sub> error similar to that of version 4 may occur if the CSAT is sufficiently out of calibration. An empirical correction to the CSAT heat flux that is consistent with our conceptual understanding of the <i>T</i><sub>s</sub> error is presented. Within a broader context, the surface energy balance is used to evaluate the heat flux measurements, and the usefulness of side-by-side instrument comparisons is discussed

Differential rates of perinatal maturation of human primary and nonprimary auditory cortex

Abstract Primary and nonprimary cerebral cortex mature along different timescales; however, the differences between the rates of maturation of primary and nonprimary cortex are unclear. Cortical maturation can be measured through changes in tissue microstructure detectable by diffusion magnetic resonance imaging (MRI). In this study, diffusion tensor imaging (DTI) was used to characterize the maturation of Heschl’s gyrus (HG), which contains both primary auditory cortex (pAC) and nonprimary auditory cortex (nAC), in 90 preterm infants between 26 and 42 weeks postmenstrual age (PMA). The preterm infants were in different acoustical environments during their hospitalization: 46 in open ward beds and 44 in single rooms. A control group consisted of 15 term-born infants. Diffusion parameters revealed that (1) changes in cortical microstructure that accompany cortical maturation had largely already occurred in pAC by 28 weeks PMA, and (2) rapid changes were taking place in nAC between 26 and 42 weeks PMA. At term equivalent PMA, diffusion parameters for auditory cortex were different between preterm infants and term control infants, reflecting either delayed maturation or injury. No effect of room type was observed. For the preterm group, disturbed maturation of nonprimary (but not primary) auditory cortex was associated with poorer language performance at age two years

Soil, plant, and transport influences on methane in a subalpine forest under high ultraviolet irradiance

Recent studies have demonstrated direct methane emission from plant foliage under aerobic conditions, particularly under high ultraviolet (UV) irradiance. We examined the potential importance of this phenomenon in a high-elevation conifer forest using micrometeorological techniques. Vertical profiles of methane and carbon dioxide in forest air were monitored every 2 h for 6 weeks in summer 2007. Day to day variability in above-canopy CH<sub>4</sub> was high, with observed values in the range 1790 to 1910 nmol mol<sup>−1</sup>. High CH<sub>4</sub> was correlated with high carbon monoxide and related to wind direction, consistent with pollutant transport from an urban area by a well-studied mountain-plain wind system. Soils were moderately dry during the study. Vertical gradients of CH<sub>4</sub> were small but detectable day and night, both near the ground and within the vegetation canopy. Gradients near the ground were consistent with the forest soil being a net CH<sub>4</sub> sink. Using scalar similarity with CO<sub>2</sub>, the magnitude of the summer soil CH<sub>4</sub> sink was estimated at ~1.7 mg CH<sub>4</sub> m<sup>−2</sup> h<sup>−1</sup>, which is similar to other temperate forest upland soils. The high-elevation forest was naturally exposed to high UV irradiance under clear sky conditions, with observed peak UVB irradiance >2 W m<sup>−2</sup>. Gradients and means of CO<sub>2</sub> within the canopy under daytime conditions showed net uptake of CO<sub>2</sub> due to photosynthetic drawdown as expected. No evidence was found for a significant foliar CH<sub>4</sub> source in the vegetation canopy, even under high UV conditions. While the possibility of a weak foliar source cannot be excluded given the observed soil sink, overall this subalpine forest was a net sink for atmospheric methane during the growing season

Drought supersedes warming in determining volatile and tissue defenses of piñon pine (Pinus edulis)

Trees are suffering mortality across the globe as a result of drought, warming, and biotic attacks. The combined effects of warming and drought on in situ tree chemical defenses against herbivory have not been studied to date. To address this, we transplanted mature pinon pine trees-a well-studied species that has undergone extensive drought and herbivore-related mortality-within their native woodland habitat and also to a hotter-drier habitat and measured monoterpene emissions and concentrations across the growing season. We hypothesized that greater needle temperatures in the hotter-drier site would increase monoterpene emission rates and consequently lower needle monoterpene concentrations, and that this temperature effect would dominate the seasonal pattern of monoterpene concentrations regardless of drought. In support of our hypothesis, needle monoterpene concentrations were lower across all seasons in trees transplanted to the hotter-drier site. Contrary to our hypothesis, basal emission rates (emission rates normalized to 30 degrees C and a radiative flux of 1000 mu mol m(-2) s(-1)) did not differ between sites. This is because an increase in emissions at the hotter-drier site from a 1.5 degrees C average temperature increase was offset by decreased emissions from greater plant water stress. High emission rates were frequently observed during June, which were not related to plant physiological or environmental factors but did not occur below pre-dawn leaf water potentials of -2 MPa, the approximate zero carbon assimilation point in pinon pine. Emission rates were also not under environmental or plant physiological control when pre-dawn leaf water potential was less than -2 MPa. Our results suggest that drought may override the effects of temperature on monoterpene emissions and tissue concentrations, and that the influence of drought may occur through metabolic processes sensitive to the overall needle carbon balance.National Science Foundation, Division of Atmospheric and Geospace Sciences [0919189]; USDA National Institute of Food and Agriculture Hatch project [MONB00389, 228396]; National Science Foundation, Division of Integrative Organismal Systems [1755346]; National Science Foundation Division of Environmental Biology [1552976]; Department of the Energy National Institute for Climate Change Research (Western Region) [DE-FCO2-O6ER64159]; National Science Foundation Macrosystems Biology [EF-1340624, EF-1550756]; Critical Zone Observatories [EAR-1331408]; DIRENet [DEB-0443526]; Biosphere 2 through the Philecology Foundation (Fort Worth, TX); US Environmental Protection Agency (STAR Fellowship Assistance Agreement) [FP-91717801-0]Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Canopy nitrogen, carbon assimilation, and albedo in temperate and boreal forests: Functional relations and potential climate feedbacks

The availability of nitrogen represents a key constraint on carbon cycling in terrestrial ecosystems, and it is largely in this capacity that the role of N in the Earth\u27s climate system has been considered. Despite this, few studies have included continuous variation in plant N status as a driver of broad-scale carbon cycle analyses. This is partly because of uncertainties in how leaf-level physiological relationships scale to whole ecosystems and because methods for regional to continental detection of plant N concentrations have yet to be developed. Here, we show that ecosystem CO2 uptake capacity in temperate and boreal forests scales directly with whole-canopy N concentrations, mirroring a leaf-level trend that has been observed for woody plants worldwide. We further show that both CO2 uptake capacity and canopy N concentration are strongly and positively correlated with shortwave surface albedo. These results suggest that N plays an additional, and overlooked, role in the climate system via its influence on vegetation reflectivity and shortwave surface energy exchange. We also demonstrate that much of the spatial variation in canopy N can be detected by using broad-band satellite sensors, offering a means through which these findings can be applied toward improved application of coupled carbon cycle–climate models

Source Lines Counter (SLiC) Version 4.0

Source Lines Counter (SLiC) is a software utility designed to measure software source code size using logical source statements and other common measures for 22 of the programming languages commonly used at NASA and the aerospace industry. Such metrics can be used in a wide variety of applications, from parametric cost estimation to software defect analysis. SLiC has a variety of unique features such as automatic code search, automatic file detection, hierarchical directory totals, and spreadsheet-compatible output. SLiC was written for extensibility; new programming language support can be added with minimal effort in a short amount of time. SLiC runs on a variety of platforms including UNIX, Windows, and Mac OSX. Its straightforward command-line interface allows for customization and incorporation into the software build process for tracking development metrics.

A Radial Velocity Survey of the Cygnus OB2 Association

We conducted a radial velocity survey of the Cygnus OB2 Association over a 6 year (1999 - 2005) time interval to search for massive close binaries. During this time we obtained 1139 spectra on 146 OB stars to measure mean systemic radial velocities and radial velocity variations. We spectroscopically identify 73 new OB stars for the first time, the majority of which are likely to be Association members. Spectroscopic evidence is also presented for a B3Iae classification and temperature class variation (B3 - B8) on the order of 1 year for Cygnus OB2 No. 12. Calculations of the intial mass function with the current spectroscopic sample yield Gamma = -2.2 +/- 0.1. Of the 120 stars with the most reliable data, 36 are probable and 9 are possible single-lined spectroscopic binaries. We also identify 3 new and 8 candidate double-lined spectroscopic binaries. These data imply a lower limit on the massive binary fraction of 30% - 42%. The calculated velocity dispersion for Cygnus OB2 is 2.44 +/- km/s, which is typical of open clusters. No runaway OB stars were found.Comment: 56 pages, 23 figures, 5 tables, accepted for publication in the Astrophysical Journa

The rsmS (ybaM) mutation causes bypass suppression of the RsmAB post-transcriptional virulence regulation system in enterobacterial phytopathogens.

Plant cell wall degrading enzymes (PCWDEs) are the primary virulence determinants of soft rotting bacteria such as the potato pathogen, Pectobacterium atrosepticum. The regulation of secondary metabolite (Rsm) system controls production of PCWDEs in response to changing nutrient conditions. This work identified a new suppressor of an rsmB mutation - ECA1172 or rsmS (rsmB suppressor). Mutants defective in rsmB (encoding a small regulatory RNA), show reduced elaboration of the quorum sensing molecule (N-3-oxohexanoyl-homoserine lactone; OHHL) and PCWDEs. However, OHHL and PCWDE production were partially restored in an rsmB, rsmS double mutant. Single rsmS mutants, overproduced PCWDEs and OHHL relative to wild type P. atrosepticum and exhibited hypervirulence in potato. RsmS overproduction also resulted in increased PCWDEs and OHHL. Homology searches revealed rsmS conservation across pathogens such as Escherichia coli (ybaM), Dickeya solani, Klebsiella pneumoniae and Shigella flexneri. An rsmS mutant of Pectobacterium carotovorum ATCC39048 showed bypass of rsmB-dependent repression of PCWDEs and OHHL production. P. carotovorum ATCC39048 produces the β-lactam antibiotic, 1-carbapen-2-em-3-carboxylic acid (a carbapenem). Production of the antibiotic was repressed in an rsmB mutant but partially restored in an rsmB, rsmS double mutant. This work highlights the importance of RsmS, as a conserved pleiotropic regulator of virulence and antibiotic biosynthesis.James Hutton Institut