1,672 research outputs found
Federal Reserve Behavior Since 1980: A Financial Markets Perspective
The financial market's understanding of Federal Reserve behavior is used to examine recent changes in monetary policy. Changes in the level of interest rats in response to specific types of economic information are primarily considered. Differences in the volatility of interest rates across period provide additional evidence on changes in monetary policy regimes. The results indicate that monetary policy changed several times since 1980 with respect to either the Federal Reserve's targets, its desire to achieve its targets, or its operating procedures. The different regimes correspond to Federal Reserve statements about changes in policy. In this context, then, the evidence suggests that policy was credible.
TEAMS: Indoor Air Quality (IAR) Program
The Carrollton-Farmers Branch Independent School District (âCFBISDâ) found the need to reduce air quality concerns and complaints, and find an effective and efficient method to reduce the rising cost of utilities. An Indoor Air Quality (IAQ) program was required to embrace the two needs with the overall objective to educate allâteachers, administrators, various departments, and students. The educational outreach program chosen is TEAMS, which is the IAQ program designed to attain these goals.
The CFBISD prides itself in acting quickly to resolve IAQ issues. Our belief is problems defined and recognized, create trust, and enable the District to maximize potential for performance improvements via reduced concerns by staff.
Weâve had our IAQ program in place since April of 2002. Recognizing the need to expand the program in depth and breadth, we designed TEAMS. We were able to do this by assistance from Mike Miller and the EPA, who gave the District six âTools for Schoolsâ test kits (TfS Kit). The information from these kits gave us a guideline to build TEAMS to meet our objectives of reaching a larger audience with additional material, and adding to the goals of TEAMS increased efficiency, reduced cost, and educated consumers
Sub-grid scale representation of vegetation in global land surface schemes: implications for estimation of the terrestrial carbon sink
Terrestrial ecosystem models commonly represent vegetation in terms of
plant functional types (PFTs) and use their vegetation attributes in
calculations of the energy and water balance as well as to investigate the
terrestrial carbon cycle. Sub-grid scale variability of PFTs in these models
is represented using different approaches with the "composite" and
"mosaic" approaches being the two end-members.
The impact of these two approaches on the global carbon
balance has been investigated with the Canadian Terrestrial Ecosystem
Model (CTEM v 1.2) coupled to the Canadian Land Surface Scheme (CLASS
v 3.6). In the composite (single-tile) approach, the vegetation
attributes of different PFTs present in a grid cell are aggregated and
used in calculations to determine the resulting physical environmental
conditions (soil moisture, soil temperature, etc.) that are common to
all PFTs. In the mosaic (multi-tile) approach, energy and water
balance calculations are performed separately for each PFT tile and
each tile's physical land surface environmental conditions evolve
independently. Pre-industrial equilibrium CLASS-CTEM simulations yield
global totals of vegetation biomass, net primary productivity, and
soil carbon that compare reasonably well with observation-based
estimates and differ by less than 5% between the mosaic and
composite configurations. However, on a regional scale the two
approaches can differ by > 30%, especially in areas with
high heterogeneity in land cover. Simulations over the historical
period (1959â2005) show different responses to evolving climate and
carbon dioxide concentrations from the two approaches. The cumulative
global terrestrial carbon sink estimated over the 1959â2005 period
(excluding land use change (LUC) effects) differs by around
5% between the two approaches (96.3 and 101.3 Pg, for the
mosaic and composite approaches, respectively) and compares well with
the observation-based estimate of 82.2 ± 35 Pg C over the same
period. Inclusion of LUC causes the estimates of the terrestrial C
sink to differ by 15.2 Pg C (16%) with values of 95.1 and
79.9 Pg C for the mosaic and composite approaches,
respectively. Spatial differences in simulated vegetation and soil
carbon and the manner in which terrestrial carbon balance evolves in
response to LUC, in the two approaches, yields a substantially
different estimate of the global land carbon sink. These results
demonstrate that the spatial representation of vegetation has an
important impact on the model response to changing climate,
atmospheric CO<sub>2</sub> concentrations, and land cover
TEAMS: Indoor Air Quality (IAR) Program
The Carrollton-Farmers Branch Independent School District (âCFBISDâ) found the need to reduce air quality concerns and complaints, and find an effective and efficient method to reduce the rising cost of utilities. An Indoor Air Quality (IAQ) program was required to embrace the two needs with the overall objective to educate allâteachers, administrators, various departments, and students. The educational outreach program chosen is TEAMS, which is the IAQ program designed to attain these goals.
The CFBISD prides itself in acting quickly to resolve IAQ issues. Our belief is problems defined and recognized, create trust, and enable the District to maximize potential for performance improvements via reduced concerns by staff.
Weâve had our IAQ program in place since April of 2002. Recognizing the need to expand the program in depth and breadth, we designed TEAMS. We were able to do this by assistance from Mike Miller and the EPA, who gave the District six âTools for Schoolsâ test kits (TfS Kit). The information from these kits gave us a guideline to build TEAMS to meet our objectives of reaching a larger audience with additional material, and adding to the goals of TEAMS increased efficiency, reduced cost, and educated consumers
The influence of soils on heterotrophic respiration exerts a strong control on net ecosystem productivity in seasonally dry Amazonian forests
Net ecosystem productivity of carbon (NEP) in seasonally dry forests
of the Amazon varies greatly between sites with similar
precipitation patterns. Correctly modeling the NEP seasonality with
terrestrial ecosystem models has proven difficult. Previous
modelling studies have mostly advocated for incorporating processes that
act to reduce water stress on gross primary productivity (GPP)
during the dry season, such as deep soils and roots,
plant-mediated hydraulic redistribution of soil moisture, and
increased dry season leaf litter generation which reduces leaf age
and thus increases photosynthetic capacity. Recent observations,
however, indicate that seasonality in heterotrophic respiration also
contributes to the observed seasonal cycle of NEP. Here, we use the
dynamic vegetation model CLASS-CTEM (Canadian Land
Surface SchemeâCanadian Terrestrial
Ecosystem Model) â without deep soils or roots,
hydraulic redistribution of soil moisture, or increased dry season
litter generation â at two Large-Scale BiosphereâAtmosphere
Experiment (LBA) sites (TapajĂłs km 83 and JarĂș
Reserve). These LBA sites exhibit opposite seasonal NEP cycles
despite reasonably similar meteorological conditions. Our simulations are able
to reproduce the observed NEP seasonality at both sites. Simulated
GPP, heterotrophic respiration, latent and sensible heat fluxes,
litter fall rate, soil moisture and temperature, and basic
vegetation state are also compared with available observation-based
estimates which provide confidence that overall the model behaves
realistically at the two sites.
Our results indicate that
representing the effect of soil moisture on heterotrophic respiration in terms of soil matric potential and constraining
heterotrophic respiration when absolute soil matric potential is both low (wetter soils) and high (drier soils), with optimum conditions in between, allows
%appropriately representing the influence of soil texture and depth,
%through soil moisture, on seasonal patterns of GPP and, especially,
% heterotrophic respiration is important
to correctly simulate NEP
seasonality
The antihypertensive MTHFR gene polymorphism rs17367504-G is a possible novel protective locus for preeclampsia
Objective: Preeclampsia is a complex heterogeneous disease commonly defined by new-onset hypertension and proteinuria in pregnancy. Women experiencing preeclampsia have increased risk for cardiovascular diseases (CVD) later in life. Preeclampsia and CVD share risk factors and pathophysiologic mechanisms, including dysregulated inflammation and raised blood pressure. Despite commonalities, little is known about the contribution of shared genes (pleiotropy) to these diseases. This study aimed to investigate whether genetic risk factors for hypertension or inflammation are pleiotropic by also being associated with preeclampsia. Methods: We genotyped 122 single nucleotide polymorphisms (SNPs) in women with preeclampsia (nâ=â1006) and nonpreeclamptic controls (nâ=â816) from the Norwegian HUNT Study. SNPs were chosen on the basis of previously reported associations with either nongestational hypertension or inflammation in genome-wide association studies. The SNPs were tested for association with preeclampsia in a multiple logistic regression model. Results: The minor (G) allele of the intronic SNP rs17367504 in the gene methylenetetrahydrofolate reductase (MTHFR) was associated with a protective effect on preeclampsia (odds ratio 0.65, 95% confidence interval 0.53â0.80) in the Norwegian cohort. This association did not replicate in an Australian preeclampsia caseâcontrol cohort (Pâ=â0.68, odds ratio 1.05, 95% confidence interval 0.83â1.32, minor allele frequencyâ=â0.15). Conclusion: MTHFR is important for regulating transmethylation processes and is involved in regulation of folate metabolism. The G allele of rs17367504 has previously been shown to protect against nongestational hypertension. Our study suggests a novel association between this allele and reduced risk for preeclampsia. This is the first study associating the minor (G) allele of a SNP within the MTHFR gene with a protective effect on preeclampsia, and in doing so identifying a possible pleiotropic protective effect on preeclampsia and hypertension
VIPER Integrated MDAO Analysis for Conceptual Design of Supersonic X-Plane Vehicles
A streamlined Multi-Disciplinary Analysis and Optimization (MDAO) process is being developed to provide feedback on conceptual designs and early airspace modeling assessments of unconventional aircraft. This MDAO process has been demonstrated using a Low-Boom Flight Demonstrator (LBFD) like configuration by performing a trade study of various flap sizes. The results of this trade showed that shorter takeoff distances are achieved with increased flap chord and flap deflections. This trend is unlike conventional transport type aircraft which typically show increased required takeoff distances due to the increased drag during its take-off flap configurations. The LBFD like configuration results are attributed to its high engine thrust which overcomes the higher drag associated with these takeoff flap configurations
An assessment of natural methane fluxes simulated by the CLASS-CTEM model
Natural methane emissions from wetlands and fire, and soil uptake of methane,
simulated using the Canadian Land Surface Scheme and Canadian Terrestrial
Ecosystem (CLASS-CTEM) modelling framework, over the historical 1850â2008
period, are assessed by using a one-box model of atmospheric methane burden.
This one-box model also requires anthropogenic emissions and the methane sink
in the atmosphere to simulate the historical evolution of global methane
burden. For this purpose, global anthropogenic methane emissions for the
period 1850â2008 were reconstructed based on the harmonized representative
concentration pathway (RCP) and Emission Database for Global Atmospheric
Research (EDGAR) data sets. The methane sink in the atmosphere is represented
using bias-corrected methane lifetimes from the Canadian Middle Atmosphere
Model (CMAM). The resulting evolution of atmospheric methane concentration
over the historical period compares reasonably well with observation-based
estimates (correlation â=â 0.99, root mean square error â=â 35 ppb). The
modelled natural emissions are also assessed using an inverse procedure where
the methane lifetimes required to reproduce the observed year-to-year
increase in atmospheric methane burden are calculated based upon the
specified global anthropogenic and modelled natural emissions that we have
used here. These calculated methane lifetimes over the historical period fall
within the uncertainty range of observation-based estimates. The present-day
(2000â2008) values of modelled methane emissions from wetlands (169 Tg CH4 yrâ1) and fire (27 Tg CH4 yrâ1),
methane uptake by soil (29 Tg CH4 yrâ1), and the budget terms associated with overall anthropogenic and
natural emissions are consistent with estimates reported in a recent global
methane budget that is based on top-down approaches constrained by observed
atmospheric methane burden. The modelled wetland emissions increase over the
historical period in response to both increases in precipitation and
in atmospheric CO2 concentration. This increase in wetland emissions
over the historical period yields evolution of the atmospheric methane
concentration that compares better with observation-based values than the
case when wetland emissions are held constant over the historical period.</p
Acute Modifications of Circulating Volume and Respiratory Maneuvers in the Cardiovascular Assessment of Long-Duration Crewmembers
This U.S. - Russian project is aimed at improved assessment of cardiac and vascular parameters associated with circulating volume and its distribution in long-duration space flight. Objective responses to modified Valsalva and Mueller maneuvers were measured by cardiac and vascular ultrasound before, during, and after temporary volume redistribution by means of Braslet-M thigh occlusion cuffs (Russia). Braslet-M cuffs are custom fitted to each crewmember prior to launch on the Soyuz as a Russian countermeasure for space adaptation fluid shift
Right Ventricular Tissue Doppler Assessment in Space During Circulating Volume Modification using the Braslet-M Device
This joint U.S. - Russian work aims to establish a methodology for assessing cardiac function in microgravity in association with manipulation of central circulating volume. Russian Braslet-M occlusion cuffs were used to temporarily increase the volume of blood in the lower extremities, which effectively reduces the volume returning to the heart in the central circulation. A novel methodology was tested on the International Space Station (ISS) to assess the volume status of crewmembers by evaluating the responses to application and release of the Braslet-on-occlusion cuffs, as well as to modified Valsalva and Mueller maneuvers. Baseline echocardiographic tissue Doppler imaging (TDI) of the right ventricular free wall with no Braslet applied shows early diastolic E' (16 cm/sec), late diastolic A' (14 cm/sec), and systolic (12 cm/sec) velocities compatible with normal subjects on Earth. TDI of the RV free wall with Braslet applied shows that early diastolic E' decreased by 50% (8 cm/sec), late diastolic A' increased by 45%, and systolic S' remains unchanged. TDI of the RV free wall approximately 8 beats after the Braslet was released shows early diastolic E' (8 cm/sec), late diastolic A' (12 cm/sec), and systolic S' (13 cm/sec) velocities. During this portion of the release, early diastolic E' did not recover to baseline values but late diastolic A' and systolic S' recovered to pre-Braslet values. The pre-systolic cross-sectional area of the internal jugular vein with Braslet off was 1.07 cm(sup 2) and 1.13 cm(sup 2) 10 min after the Braslet was applied. The presystolic cross-sectional area of the common femoral vein with Braslet off was 0.50 cm(sup 2), and was 0.54 cm(sup 2) 10 min after the Braslet was applied. The right ventricular myocardial performance Tei index also was calculated for comparison with typical values found in healthy subjects on Earth. Baseline and Braslet-on values for Tei index were 0.25 and 0.22 respectively. Braslet Tei indices are within normal ranges found in healthy subjects and temporarily become greater than 0.4 during the dynamic Braslet release portion of this study. Tissue Doppler imaging of the right ventricle revealed that the Braslet influenced cardiac preload and that fluid was sequestered in the lower-extremity interstitial and vascular space after only 10 minutes of application. This report demonstrates that Braslet application affects right ventricular physiology in long-duration space flight based on TDI and that this effect is in part due to venous hemodynamics
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