Volume mixing ratio profiles of HCl, HOCl, ClNO3, CH3Cl, CFC-12, and CFC-11, CCl4, HCFC-22, and CFC-113 were measured simultaneously from 9 to 38 km by the Jet Propulsion Laboratory MkIV Fourier ...Transform Infrared solar absorption spectrometer during two balloon flights from Fairbanks, Alaska (64.8 N), on May 8 and July 8, 1997. The altitude variation of total organic chlorine (CCl(sub y)), total inorganic chlorine (Cl(sub y)), and the nearly constant value (3.7 +/- 0.2 ppbv) of their sum (Cl(sub TOT)) demonstrates that the stratospheric chlorine species available to react with O3 are supplied by the decomposition of organic chlorinated compounds whose abundances are well quantified. Measured profiles of HCl and ClNO3 agree well with profiles found by photochemical model (differences < 10% for altitudes below 35 km) constrained by various other constituents measured by MkIV. The production of HCl by ClO + OH plays a relatively small role in the partitioning of HCl and ClNO3 for the sampled air masses. However, better agreement with the measured profiles of HCl and ClNO3 is obtained when this source of HCl is included in the model. Both the measured and calculated ClNO3/HCl ratios exhibit the expected near linear variation with O3(sup 2)/CH4 over a broad range of altitudes. MkIV measurements of HCl, ClNO3, and CCl(sub y) agree well with ER-2 in situ observations of these quantities for directly comparable air masses. These results demonstrate good understanding of the budget of stratospheric chlorine and that the partitioning of inorganic chlorine is accurately described by photochemical models that employ JPL97 reaction rates and production of HCl from ClO + OH for the environmental conditions encountered: relatively warm temperatures, long periods of solar illumination, and relatively low aerosol surface areas.
Undernourished children exhibit impaired development of their gut microbiota. Transplanting microbiota from 6- and 18-month-old healthy or undernourished Malawian donors into young germ-free mice ...that were fed a Malawian diet revealed that immature microbiota from undernourished infants and children transmit impaired growth phenotypes. The representation of several age-discriminatory taxa in recipient animals correlated with lean body mass gain; liver, muscle, and brain metabolism; and bone morphology. Mice were cohoused shortly after receiving microbiota from healthy or severely stunted and underweight infants; age- and growth-discriminatory taxa from the microbiota of the former were able to invade that of the latter, which prevented growth impairments in recipient animals. Adding two invasive species, Ruminococcus gnavus and Clostridium symbiosum, to the microbiota from undernourished donors also ameliorated growth and metabolic abnormalities in recipient animals. These results provide evidence that microbiota immaturity is causally related to undernutrition and reveal potential therapeutic targets and agents.
We describe a method of evaluating systematic errors in measurements of total column dry-air mole fractions of CO sub(2) (X sub(CO2)) from space, and we illustrate the method by applying it to the ...v2.8 Atmospheric CO sub(2) Observations from Space retrievals of the Greenhouse Gases Observing Satellite (ACOS-GOSAT) measurements over land. The approach exploits the lack of large gradients in X sub(CO2) south of 25 degree S to identify large-scale offsets and other biases in the ACOS-GOSAT data with several retrieval parameters and errors in instrument calibration. We demonstrate the effectiveness of the method by comparing the ACOS-GOSAT data in the Northern Hemisphere with ground truth provided by the Total Carbon Column Observing Network (TCCON). We use the observed correlation between free-tropospheric potential temperature and X sub(CO2) in the Northern Hemisphere to define a dynamically informed coincidence criterion between the ground-based TCCON measurements and the ACOS-GOSAT measurements. We illustrate that this approach provides larger sample sizes, hence giving a more robust comparison than one that simply uses time, latitude and longitude criteria. Our results show that the agreement with the TCCON data improves after accounting for the systematic errors, but that extrapolation to conditions found outside the region south of 25 degree S may be problematic (e.g., high airmasses, large surface pressure biases, M-gain, measurements made over ocean). A preliminary evaluation of the improved v2.9 ACOS-GOSAT data is also discussed.
Thermal infrared radiances from the Tropospheric Emission Spectrometer (TES) between 10 and 15 μm contain significant carbon dioxide (CO.sub.2) information, however the CO.sub.2 signal must be ...separated from radiative interference from temperature, surface and cloud parameters, water, and other trace gases. Validation requires data sources spanning the range of TES CO.sub.2 sensitivity, which is approximately 2.5 to 12 km with peak sensitivity at about 5 km and the range of TES observations in latitude (40° S to 40° N) and time (2005-2011). We therefore characterize Tropospheric Emission Spectrometer (TES) CO.sub.2 version 5 biases and errors through comparisons to ocean and land-based aircraft profiles and to the CarbonTracker assimilation system. We compare to ocean profiles from the first three Hiaper Pole-to-Pole Observations (HIPPO) campaigns between 40° S and 40° N with measurements between the surface and 14 km and find that TES CO.sub.2 estimates capture the seasonal and latitudinal gradients observed by HIPPO CO.sub.2 measurements. Actual errors range from 0.8-1.8 ppm, depending on the campaign and pressure level, and are approximately 1.6-2 times larger than the predicted errors. The bias of TES versus HIPPO is within 1 ppm for all pressures and datasets; however, several of the sub-tropical TES CO.sub.2 estimates are lower than expected based on the calculated errors. Comparisons to land aircraft profiles from the United States Southern Great Plains (SGP) Atmospheric Radiation Measurement (ARM) between 2005 and 2011 measured from the surface to 5 km to TES CO.sub.2 show good agreement with an overall bias of -0.3 ppm to 0.1 ppm and standard deviations of 0.8 to 1.0 ppm at different pressure levels. Extending the SGP aircraft profiles above 5 km using AIRS or CONTRAIL measurements improves comparisons with TES. Comparisons to CarbonTracker (version CT2011) show a persistent spatially dependent bias pattern and comparisons to SGP show a time-dependent bias of -0.2 ppm yr.sup.-1 . We also find that the predicted sensitivity of the TES CO.sub.2 estimates is too high, which results from using a multi-step retrieval for CO.sub.2 and temperature. We find that the averaging kernel in the TES product corrected by a pressure-dependent factor accurately reflects the sensitivity of the TES CO.sub.2 product.
We characterize the spring and fall stratospheric distribution of CO at 49°N‐55°S latitude from ATMOS profiles measured during 4 shuttle flights. Measured mixing ratios increase with potential ...temperature (θ) from 12 ppbv (10−9 per unit volume) at 525 K, to 30–40 ppbv at 1750 K with only minor variations with latitude and season at a θ level. Evidence for some confinement near 1150 K in the developing November 1994 vortex is indicated from comparison of CO and N2O horizontal gradients. Measured CO mixing ratios at the tropical tropopause are a factor of 10 higher than values calculated with a steady‐state model using standard photochemistry constrained by correlative temperatures and pressures, and ATMOS measurements including CH4 as inputs. Differences decrease with latitude at constant θ and are <20% at 800 K and all latitudes, where the CO photochemical lifetime is 40–50 days.
Ground‐based solar absorption spectra were measured from Fairbanks, Alaska (65°N, 148°W) from March to September 1997 by the Jet Propulsion Laboratory (JPL) MkIV Fourier transform infrared (FTIR) ...spectrometer. The derived column abundances of O3 declined by 35% over this period (20% in April and May, and 15% during the summer), whereas those of HF, a long‐lived tracer, changed by less than 5%. High‐latitude, summertime balloon observations reveal similar shapes for the volume mixing ratio profiles of O3 and HF in the lower stratosphere, where most of their column abundance resides. Vertical transport should therefore have similar effects on the column abundances of O3 and HF. Data from the Halogen Occultation Experiment (HALOE) show a poleward decrease in the O3/HF ratio at all stratospheric altitudes, so that any reductions in column O3 due to horizontal meridional transport would have been accompanied by even larger reductions in column HF. Therefore the observed column O3 decrease must be the result of chemical loss processes. Column measurements of other atmospheric gases show a summertime maximum in the NOx/NOy column ratio and little change in the chlorine partitioning. We conclude that most of the reduction in column O3 over Fairbanks from March to September 1997 was likely driven by NOx chemistry. These conclusions are supported by the similar behavior of column abundances measured by another ground‐based FTIR spectrometer based in Ny Ålesund, Spitsbergen, (79°N, 12°E).
Ground‐based solar absorption spectra were measured from Fairbanks, Alaska (65°N, 148°W) from March to September 1997 by the Jet Propulsion Laboratory (JPL) MkIV Fourier transform infrared (FTIR) ...spectrometer. The derived column abundances of O
3
declined by 35% over this period (20% in April and May, and 15% during the summer), whereas those of HF, a long‐lived tracer, changed by less than 5%. High‐latitude, summertime balloon observations reveal similar shapes for the volume mixing ratio profiles of O
3
and HF in the lower stratosphere, where most of their column abundance resides. Vertical transport should therefore have similar effects on the column abundances of O
3
and HF. Data from the Halogen Occultation Experiment (HALOE) show a poleward decrease in the O
3
/HF ratio at all stratospheric altitudes, so that any reductions in column O
3
due to horizontal meridional transport would have been accompanied by even larger reductions in column HF. Therefore the observed column O
3
decrease must be the result of chemical loss processes. Column measurements of other atmospheric gases show a summertime maximum in the NO
x
/NO
y
column ratio and little change in the chlorine partitioning. We conclude that most of the reduction in column O
3
over Fairbanks from March to September 1997 was likely driven by NO
x
chemistry. These conclusions are supported by the similar behavior of column abundances measured by another ground‐based FTIR spectrometer based in Ny Ålesund, Spitsbergen, (79°N, 12°E).
To assess the safety and efficacy of redilation of central venous stents in a growing animal model.
Palmaz stents were placed in the inferior vena cava (IVC) in 18 newborn lambs. After 5 months, vena ...cavography was performed. Those animals in which growth of the IVC adjacent to the stent and/or neointimal hyperplasia had resulted in a stenosis were considered candidates for redilation. Repeat vena cavography, intravascular ultrasound, and histologic examination were performed at 2 or 6 months.
A stenosis of > 20% was demonstrated in 13 animals. Redilation was performed, and a 50% mean increase in stent diameter was achieved. There were no immediate complications. Late complications included nonocclusive laminar clot (n = 2), and a bar of tissue dividing but not occluding the caval lumen (n = 1). Moderate neointimal hyperplasia occurred in all stents. Stent compression (unrelated to redilation) occurred in seven animals.
Palmaz stents can be redilated safely and effectively in an animal model of growing central veins.
Prediction models are useful tools in the clinical management of colon cancer patients, particularly when estimating the recurrence rate and, thus, the need for adjuvant treatment. However, the most ...used models (MSKCC, ACCENT) are based on several decades-old patient series from clinical trials, likely overestimating the current risk of recurrence, especially in low-risk groups, as outcomes have improved over time. The aim was to develop and validate an updated model for the prediction of recurrence within 5 years after surgery using routinely collected clinicopathologic variables.
A population-based cohort from the Swedish Colorectal Cancer Registry of 16,134 stage I-III colon cancer cases was used. A multivariable model was constructed using Cox proportional hazards regression. Three-quarters of the cases were used for model development and one quarter for internal validation. External validation was performed using 12,769 stage II-III patients from the Norwegian Colorectal Cancer Registry. The model was compared to previous nomograms.
The nomogram consisted of eight variables: sex, sidedness, pT-substages, number of positive and found lymph nodes, emergency surgery, lymphovascular and perineural invasion. The area under the curve (AUC) was 0.78 in the model, 0.76 in internal validation, and 0.70 in external validation. The model calibrated well, especially in low-risk patients, and performed better than existing nomograms in the Swedish registry data. The new nomogram's AUC was equal to that of the MSKCC but the calibration was better.
The nomogram based on recently operated patients from a population registry predicts recurrence risk more accurately than previous nomograms. It performs best in the low-risk groups where the risk-benefit ratio of adjuvant treatment is debatable and the need for an accurate prediction model is the largest.
To evaluate the feasibility of direct intravascular determination of renal artery (RA) blood flow with a Doppler probetipped guide wire.
Potential renal donors (n = 10) with normal RAs (n = 23) ...underwent evaluation of RA blood flow velocity with use of a 0.018-inch, 12-MHz Doppler guide wire. The RA average peak velocity (APV) was obtained with the flow wire. RA diameter was obtained from the filmed images with magnification corrected to a known standard or by a computerized quantification program. These data were used to determine the vessel's cross-sectional area (CSA).
The right and left RA APV, CSA, and blood flow differed insignificantly within the group and averaged 9.7 and 9.0 cm/sec (P = .43), 0.417 and 0.357 cm2 (P = .22), and 382 and 370 mL/min (P = .43), respectively. However, in individuals, the RA CSA and total volumetric blood flow varied by a mean of 29% (range, 4%-56%) and 50% (range, 19%-128%), respectively.
This study demonstrates that direct intravascular determination of RA blood flow with a Doppler-tipped wire is both feasible and relatively uncomplicated. Results indicate that blood flow can vary significantly, both in kidneys within the same individual and from person to person. The Doppler wire may facilitate measurements of RA blood flow during endoluminal interventions and help determine an optimal endpoint for these procedures.
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