2,366 research outputs found
Incorporating Hydraulic Structures in an Open-Channel Model
The open-channel flow model, BRANCH, is a routinely used numerical tool for modeling rivers, canals, and waterway networks. Although a simplified hydraulic structure representation is included in the model, no universal subroutine that can represent hydraulic structures by their rating curve equations has been included in the BRANCH model. Accordingly, a subroutine has been developed that specifies flow through a structure by a stage-discharge relation. The structure flow equation is used to generate coefficients in the solution matrix that represent the structure in the same computational format as the open-channel flow equations. Field applications have shown that this new subroutine properly represents the effects of hydraulic structures in the open-channel flow regime
Applying Downscaled Global Climate Model Data to a Hydrodynamic Surface-Water and Groundwater Model
Precipitation data from Global Climate Models have been downscaled to smaller regions. Adapting this downscaled precipitation data to a coupled hydrodynamic surface-water/groundwater model of southern Florida allows an examination of future conditions and their effect on groundwater levels, inundation patterns, surface-water stage and flows, and salinity. The downscaled rainfall data include the 1996-2001 time series from the European Center for MediumRange Weather Forecasting ERA-40 simulation and both the 1996-1999 and 2038-2057 time series from two global climate models: the Community Climate System Model (CCSM) and the Geophysical Fluid Dynamic Laboratory (GFDL). Synthesized surface-water inflow datasets were developed for the 2038-2057 simulations. The resulting hydrologic simulations, with and without a 30-cm sea-level rise, were compared with each other and field data to analyze a range of projected conditions. Simulations predicted generally higher future stage and groundwater levels and surface-water flows, with sea-level rise inducing higher coastal salinities. A coincident rise in sea level, precipitation and surface-water flows resulted in a narrower inland saline/fresh transition zone. The inland areas were affected more by the rainfall difference than the sea-level rise, and the rainfall differences make little difference in coastal inundation, but a larger difference in coastal salinities
The Implications of M Dwarf Flares on the Detection and Characterization of Exoplanets at Infrared Wavelengths
We present the results of an observational campaign which obtained high time
cadence, high precision, simultaneous optical and IR photometric observations
of three M dwarf flare stars for 47 hours. The campaign was designed to
characterize the behavior of energetic flare events, which routinely occur on M
dwarfs, at IR wavelengths to milli-magnitude precision, and quantify to what
extent such events might influence current and future efforts to detect and
characterize extrasolar planets surrounding these stars. We detected and
characterized four highly energetic optical flares having U-band total energies
of ~7.8x10^30 to ~1.3x10^32 ergs, and found no corresponding response in the J,
H, or Ks bandpasses at the precision of our data. For active dM3e stars, we
find that a ~1.3x10^32 erg U-band flare (delta Umax ~1.5 mag) will induce <8.3
(J), <8.5 (H), and <11.7 (Ks) milli-mags of a response. A flare of this energy
or greater should occur less than once per 18 hours. For active dM4.5e stars,
we find that a ~5.1x10^31 erg U-band flare (delta Umax ~1.6 mag) will induce
<7.8 (J), <8.8 (H), and <5.1 (Ks) milli-mags of a response. A flare of this
energy or greater should occur less than once per 10 hours. No evidence of
stellar variability not associated with discrete flare events was observed at
the level of ~3.9 milli-mags over 1 hour time-scales and at the level of ~5.6
milli-mags over 7.5 hour time-scales. We therefore demonstrate that most M
dwarf stellar activity and flares will not influence IR detection and
characterization studies of M dwarf exoplanets above the level of ~5-11
milli-mags, depending on the filter and spectral type. We speculate that the
most energetic megaflares on M dwarfs, which occur at rates of once per month,
are likely to be easily detected in IR observations with sensitivity of tens of
milli-mags.Comment: Accepted in Astronomical Journal, 17 pages, 6 figure
Vegetation Drought Response Index An Integration of Satellite, Climate, and Biophysical Data
Drought is a normal, recurring feature of climate in most parts of the world (Wilhite, 2000) that adversely affects vegetation conditions and can have significant impacts on agriculture, ecosystems, food security, human health, water resources, and the economy. For example, in the United States, 14 billion-dollar drought events occurred between 1980 and 2009 (NCDC, 2010), with a large proportion of the losses coming from the agricultural sector in the form of crop yield reductions and degraded hay/pasture conditions. During the 2002 drought, Hayes et al. (2004) found that many individual states across the United States experienced more than $1 billion in agriculture losses associated with both crops and livestock. The impact of drought on vegetation can have serious water resource implications as the use of finite surface and groundwater supplies to support agricultural crop production competes against other sectoral water interests (e.g., environmental, commercial, municipal, and recreation). Drought-related vegetation stress can also have various ecological impacts. Prime examples include widespread piñon pine tree die-off in the southwest United States due to protracted severe drought stress and associated bark beetle infestations (Breshears et al., 2005) and the geographic shift of a forest-woodland ecotone in this region in response to severe drought in the mid-1950s (Allen and Breshears, 1998). Tree mortality in response to extended drought periods has also been observed in other parts of the western United States (Guarin and Taylor, 2005), as well as in boreal (Kasischke and Turetsky, 2006), temperate (Fensham and Holman, 1999), and tropical (Williamson et al., 2000) forests. Droughts have also served as a catalyst for changes in wildfire activity (Swetnam and Betancourt, 1998; Westerling et al., 2006) and invasive plant species establishment (Everard et al., 2010)
Toward a neuroscience of interactive parent–infant dyad empathy
In accord with social neuroscience's progression to include interactive experimental paradigms, parents' brains have been activated by emotionally charged infant stimuli - especially of their own infant - including baby cry and picture. More recent research includes the use of brief video clips and opportunities for maternal response. Among brain systems important to parenting are those involved in empathy. This research may inform recent studies of decreased societal empathy, offer mechanisms and solutions
The Effects of 3 Weeks Yogic Breathing Practice on Ventilation and Running Economy
International Journal of Exercise Science 13(2): 62-74, 2020. Yogic breathing techniques (Pranayama) positively impact respiratory function (RF) in non-endurance trained individuals.The purpose of this study investigated effects of routine Pranayama practice on RF, running economy (RE) and perceptual responses. A between subject’s case-control study design was incorporated.Eleven runners practiced three styles of Pranayama (30 min/day 6 days/week) for 3 consecutive weeks (YG) and completed a VO2max tests on a treadmill (trial 1), basic RF tests, and constant workload RE trials at 60, 70, and 80% VO2max (trial 2 and 3). A control group (n= 10) (CT) completed the same pre – post testing without intervention. Pre vs. post values for resting forced vital capacity (FVC), peak expiratory flow rate (PEFR) and forced expiratory flow volume in one second (FEV1). Yoga improved FVC and FEV1, but did not significantly impact RE However, RPE-L for HIGH had an interaction (p\u3c 0.05)showing a decrease for YG and an increase for CT. The current study suggests 3 weeks of yogic Pranayama fails to significantly impact RE, however some evidence indicates YG may positively alter perceptual responses at individually prescribed workloads. More work is needed to definitively establish benefits of YG for runners
Measuring single-cell gene expression dynamics in bacteria using fluorescence time-lapse microscopy
Quantitative single-cell time-lapse microscopy is a powerful method for analyzing gene circuit dynamics and heterogeneous cell behavior. We describe the application of this method to imaging bacteria by using an automated microscopy system. This protocol has been used to analyze sporulation and competence differentiation in Bacillus subtilis, and to quantify gene regulation and its fluctuations in individual Escherichia coli cells. The protocol involves seeding and growing bacteria on small agarose pads and imaging the resulting microcolonies. Images are then reviewed and analyzed using our laboratory's custom MATLAB analysis code, which segments and tracks cells in a frame-to-frame method. This process yields quantitative expression data on cell lineages, which can illustrate dynamic expression profiles and facilitate mathematical models of gene circuits. With fast-growing bacteria, such as E. coli or B. subtilis, image acquisition can be completed in 1 d, with an additional 1–2 d for progressing through the analysis procedure
Impact of intracellular hemin on N-type inactivation of voltage-gated K+ channels
N-type inactivation of voltage-gated K+ channels is conferred by the N-terminal “ball” domains of select pore-forming α subunits or of auxiliary β subunits, and influences electrical cellular excitability. Here, we show that hemin impairs inactivation of K+ channels formed by Kv3.4 α subunits as well as that induced by the subunits Kvβ1.1, Kvβ1.2, and Kvβ3.1 when coexpressed with α subunits of the Kv1 subfamily. In Kvβ1.1, hemin interacts with cysteine and histidine residues in the N terminus (C7 and H10) with high affinity (EC50 100 nM). Similarly, rapid inactivation of Kv4.2 channels induced by the dipeptidyl peptidase-like protein DPP6a is also sensitive to hemin, and the DPP6a mutation C13S eliminates this dependence. The results suggest a common mechanismfor a dynamic regulation of Kv channel inactivation by heme/hemin in N-terminal ball domains of Kv α and auxiliary β subunits. Free intracellular heme therefore has the potential to regulate cellular excitability via modulation of Kv channel inactivation
Parenting and Beyond: Common Neurocircuits Underlying Parental and Altruistic Caregiving
Interpersonal relationships constitute the foundation on which human society is based. The infant–caregiver bond is the earliest and most influential of these relationships. Driven by evolutionary pressure for survival, parents feel compelled to provide care to their biological offspring. However, compassion for non-kin is also ubiquitous in human societies, motivating individuals to suppress their own self-interests to promote the well-being of non-kin members of the society. We argue that the process of early kinship-selective parental care provides the foundation for non-exclusive altruism via the activation of a general Caregiving System that regulates compassion in any of its forms. We propose a tripartite structure of this system that includes (1) the perception of need in another, (2) a caring motivational or feeling state, and (3) the delivery of a helping response to the individual in need. Findings from human and animal research point to specific neurobiological mechanisms including activation of the insula and the secretion of oxytocin that support the adaptive functioning of this Caregiving System
Differential Brain Activation to Angry Faces by Elite Warfighters: Neural Processing Evidence for Enhanced Threat Detection
10.1371/journal.pone.0010096PLoS ONE54
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