1,328 research outputs found
HIGH CONNECTIVITY AND MINIMAL GENETIC STRUCTURE AMONG NORTH AMERICAN BOREAL OWL (AEGOLIUS FUNEREUS) POPULATIONS, REGARDLESS OF HABITAT MATRIX
Habitat connectivity and corridors are often assumed to be critical for the persistence of patchily distributed populations, but empirical evidence for this assumption is scarce. We assessed the importance of connectivity among habitat patches for dispersal by a mature-forest obligate, the Boreal Owl (Aegolius funereus). Boreal Owls demonstrated a lack of genetic structure (theta = 0.004 +/- 0.002 [SE]) among subpopulations, regardless of matrix type and extent, which indicates that unforested matrix does not act as a barrier to dispersal for this vagile species. We found only slightly higher genetic distances (Cavalli-Sforza chord distances ranged from 0.015 to 0.025) among patchily distributed Rocky Mountain subpopulations as compared with largely contiguous boreal-forest subpopulations (0.013 to 0.019) and no evidence of a genetic split across the expansive high plains of Wyoming. Even the most isolated subalpine patches are connected via gene flow. As northern boreal forests continue to experience intensive harvest of mature stands, geographic dispersion of Boreal Owl habitat may begin to more closely resemble that found in the Rocky Mountains. We suggest that decreased connectivity poses much less of a threat to continued abundance of this mature-forest obligate than overall loss of nesting and foraging habitat. Assessment of the importance of corridors and connectivity should be conducted on a species-by-species basis, given the variation in response of species to discontinuity of habitat, even among closely related taxa or guilds
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SRAT CHEMISTRY AND ACID CONSUMPTION DURING SIMULATED DWPF MELTER FEED PREPARATION
Due to higher than expected hydrogen generation during the Tank 51-Sludge Batch 4 (SB4) qualification run, DWPF engineering requested the Savannah River National Laboratory (SRNL) to expand the ongoing catalytic hydrogen generation program. The work presented in this Technical Report was identified as part of SRNL/Liquid Waste Organization (LWO) meetings to define potential causes of catalytic hydrogen generation as well as from an external technical review panel commissioned to evaluate SRNL hydrogen related data and programs. New scope included improving the understanding of SRAT/SME process chemistry, particularly as it related to acid consumption and hydrogen generation. The expanded hydrogen program scope was covered under the technical task request (TTR): HLW-DWPF-TTR-2007-0016. A task technical and quality assurance plan (TT&QAP) was issued to cover focus areas raised in meetings with LWO plus a portion of the recommendations made by the review panel. A supporting analytical study plan was issued. It was also noted in the review of catalytic hydrogen generation that control of the DWPF acid stoichiometry was an important element in controlling hydrogen generation. A separate TTR was issued to investigate ways of improving the determination of the acid requirement during processing: HLWDWPF-TTR-0015. A separate TT&QAP was prepared for this task request. This report discusses some progress on this task related to developing alternative acid equations and to performing experimental work to supplement the existing database. Simulant preparation and preliminary flowsheet studies were already documented. The prior work produced a sufficient quantity of simulant for the hydrogen program and melter feed rheology testing. It also defined a suitable acid addition stoichiometry. The results presented in this report come from samples and process data obtained during sixteen 22-L SRAT/SME simulations that were performed in the second half of 2007 to produce eight SME products with frit 418 and a matching set of eight SME products with spherically beaded frit 418. The requirement to produce two 25 gallon batches of melter feed for the melter feed rheology modifier program fell under a separate task plan. One supporting 4-L SRAT simulation was performed with mercury, since the 22-L melter feed preparation runs had no mercury due to melter off-gas constraints. As a result of this work, a timeline of reactions has been developed showing the sequence of major reactions occurring during and shortly after acid addition. The traditional-style simulant used in this testing had fairly well defined speciation which enabled the reactions being observed to be related to acid consumption. The new coprecipitated simulants have somewhat different speciation, and it will be necessary to validate some of the conclusions from this testing using sample data from SRAT simulations with coprecipitated simulant. Noble metal dissolution data on timing and concentration were presented in a separate report discussing hydrogen generation. A few of those results will be brought into this report as part of the description of the SRAT chemistry timeline. The noble metal and mercury concentrations used in the preliminary flowsheet studies are summarized in Table 1 along with the ranges covered in this study
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IMPACT OF SB4 TANK 40 DECANT AND ARP/MCU ADDITIONS WITH/WITHOUT ADDED CAUSTIC ON DWPF CPC PERFORMANCE
The Savannah River National Laboratory (SRNL) was requested to investigate the impact of decanting supernate from the Sludge Batch four (SB4) feed in Tank 40. The specific questions concerned the potential impact on the stoichiometric acid window determined for SB4 with respect to overall hydrogen generation rates, nitrite destruction in the Sludge Receipt and Adjustment Tank (SRAT) and the rheology of the sludge, SRAT product, and Slurry Mix Evaporator (SME) product slurries. The scope included considering an addition of sodium hydroxide to Tank 40 to partially offset the sodium lost during decanting as well as considering the impact of bounding quantities of Actinide Removal Process (ARP) feed and Modular Caustic-Side Solvent Extraction Unit (MCU) feed on these same parameters. Simulated SB4 waste was first adjusted to match the dilution that has occurred in Tank 40 during the initial period of SB4 operations in the DWPF. The adjusted simulant was decanted an equivalent of 100,000 gallons relative to 413,740 gallons projected supernate volume. The decanted simulant was divided into two equal parts. One part received an addition of sodium hydroxide to increase the Na{sub 2}O content of the calcined sludge solids by about 3%. The baseline decanted simulant and caustic adjusted simulant were each tested in three pairs of DWPF process simulations of the SRAT and SME cycles. The simulations were at the nominal SB4 acid stoichiometry of 130% with and without bounding ARP/MCU additions and at 170% of acid without ARP/MCU. The 170% case without ARP/MCU was considered bounding relative to 170% with ARP/MCU based on calculated acid requirements. No significant negative impacts on the proposed acid operating window for the SRAT and SME cycles were noted in the simulations. Nitrite was successfully destroyed and mercury reduced in all six SRAT cycles. Hydrogen was produced in all six SRAT and SME cycles, but the levels were below the DWPF SRAT and SME cycle limits in all cases. Relatively insignificant rheological changes were noted other than the previously established thinning from higher acid additions. SRAT and SME processing at 130% acid stoichiometry with and without ARP/MCU additions were very similar. MCU nitric acid content, however, shifted the normal acid addition prior to boiling toward more formic acid and less nitric acid than without MCU. SRNL found no technical issues processing the proposed Tank 40 decant (with or without added NaOH) from the standpoint of the impact on the DWPF SRAT and SME cycles subject to the inherent uncertainties in modeling the ARP noble metal concentrations. The noble metals in the ARP were set to the same weight percents in the total solids that they were measured at in the SB4 waste, which was considered likely to be bounding on the actual noble metal content of the ARP transfer to DWPF. Assumptions for formate loss and nitrite to nitrate conversion can be left at the current levels
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SLUDGE BATCH 5 SIMULANT FLOWSHEET STUDIES
The Defense Waste Processing Facility (DWPF) will transition from Sludge Batch 4 (SB4) processing to Sludge Batch 5 (SB5) processing in early fiscal year 2009. Tests were conducted using non-radioactive simulants of the expected SB5 composition to determine the impact of varying the acid stoichiometry during the Sludge Receipt and Adjustment Tank (SRAT) and Slurry Mix Evaporator (SME) processes. The work was conducted to meet the Technical Task Request (TTR) HLW/DWPF/TTR-2007-0007, Rev. 1 and followed the guidelines of a Task Technical and Quality Assurance Plan (TT&QAP). The flowsheet studies are performed to evaluate the potential chemical processing issues, hydrogen generation rates, and process slurry rheological properties as a function of acid stoichiometry. Initial SB5 flowsheet studies were conducted to guide decisions during the sludge batch preparation process. These studies were conducted with the estimated SB5 composition at the time of the study. The composition has changed slightly since these studies were completed due to changes in the washing plan to prepare SB5 and the estimated SB4 heel mass. Nine DWPF process simulations were completed in 4-L laboratory-scale equipment using both a batch simulant (Tank 51 simulant after washing is complete) and a blend simulant (Tank 40 simulant after Tank 51 transfer is complete). Each simulant had a set of four SRAT and SME simulations at varying acid stoichiometry levels (115%, 130%, 145% and 160%). One additional run was made using blend simulant at 130% acid that included additions of the Actinide Removal Process (ARP) waste prior to acid addition and the Modular Caustic Side Solvent Extraction (CSSX) Unit (MCU) waste following SRAT dewatering. There are several parameters that are noteworthy concerning SB5 sludge: (1) This is the first batch DWPF will be processing that contains sludge that has had a significant fraction of aluminum removed through aluminum dissolution. (2) The sludge is high in mercury. (3) The sludge is high in noble metals. (4) The sludge is high in U and Pu--components that are not added in sludge simulants. Two SB5 processing issues were noted during testing. First, high hydrogen generation rates were measured during experiments with both the blend and batch simulant at high acid stoichiometry. Also, the reflux time was extended due to the high mercury concentration in both the batch and blend simulant. Adding ARP will extend processing times in DWPF. The ARP caustic boil took approximately six hours. The boiling time during the experiment with added MCU was 14 hours at the maximum DWPF steam flux rate. This is comparable to the DWPF processing time for dewatering plus reflux without MCU at a 5000 lbs/hr boil-up rate, but would require significantly more time at boiling at 2000-2500 lbs/hr boil-up rate. The addition of ARP and MCU did not cause any other processing issues, since foaming, rheology and hydrogen generation were less of an issue while processing with ARP/MCU
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SLUDGE BATCH 4 FOLLOW-UP QUALIFICATION STUDIES TO EVALUATE HYDROGEN GENERATION
Follow-up testing was conducted to better understand the excessive hydrogen generation seen in the initial Sludge Batch 4 (SB4) qualification Sludge Receipt and Adjustment Tank/Slurry Mix Evaporator (SRAT/SME) simulation in the Savannah River National Laboratory (SRNL) Shielded Cells. This effort included both radioactive and simulant work. The initial SB4 qualification test produced 0.59 lbs/hr hydrogen in the SRAT, which was just below the DWPF SRAT limit of 0.65 lbs/hr, and the test produced over 0.5 lbs/hr hydrogen in the SME cycle on two separate occasions, which were over the DWPF SME limit of 0.223 lbs/hr
Cross-Sectional Distribution of GARCH Coefficients across S&P 500 Constituents: Time-Variation over the Period 2000-2012
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SIMULANT DEVELOPMENT FOR SAVANNAH RIVER SITE HIGH LEVEL WASTE
The Defense Waste Processing Facility (DWPF) at the Savannah River Site vitrifies High Level Waste (HLW) for repository internment. The process consists of three major steps: waste pretreatment, vitrification, and canister decontamination/sealing. The HLW consists of insoluble metal hydroxides (primarily iron, aluminum, magnesium, manganese, and uranium) and soluble sodium salts (carbonate, hydroxide, nitrite, nitrate, and sulfate). The HLW is processed in large batches through DWPF; DWPF has recently completed processing Sludge Batch 3 (SB3) and is currently processing Sludge Batch 4 (SB4). The composition of metal species in SB4 is shown in Table 1 as a function of the ratio of a metal to iron. Simulants remove radioactive species and renormalize the remaining species. Supernate composition is shown in Table 2
Variants of the IL-10 gene associate with muscle strength in elderly from rural Africa: A candidate gene study
Recently, it has been shown that the capacity of the innate immune system to produce cytokines relates to skeletal muscle mass and strength in older persons. The interleukin-10 (IL-10) gene regulates the production capacities of IL-10 and tumour necrosis factor-α (TNF-α). In rural Ghana, IL-10 gene variants associated with different production capacities of IL-10 and TNF-α are enriched compared with Caucasian populations. In this setting, we explored the association between these gene variants and muscle strength. Among 554 Ghanaians aged 50 years and older, we determined 20 single nucleotide polymorphisms in the IL-10 gene, production capacities of IL-10 and TNF-α in whole blood upon stimulation with lipopolysaccharide (LPS) and handgrip strength as a proxy for skeletal muscle strength. We distinguished pro-inflammatory haplotypes associated with low IL-10 production capacity and anti-inflammatory haplotypes with high IL-10 production capacity. We found that distinct haplotypes of the IL-10 gene associated with handgrip strength. A pro-inflammatory haplotype with a population frequency of 43.2% was associated with higher handgrip strength (P = 0.015). An anti-inflammatory haplotype with a population frequency of 7.9% was associated with lower handgrip strength (P = 0.006). In conclusion, variants of the IL-10 gene contributing to a pro-inflammatory cytokine response associate with higher muscle strength, whereas those with anti-inflammatory response associate with lower muscle strength. Future research needs to elucidate whether these effects of variation in the IL-10 gene are exerted directly through its role in the repair of muscle tissue or indirectly through its role in the defence against infectious diseases
The Atacama Cosmology Telescope: Two-Season ACTPol Lensing Power Spectrum
We report a measurement of the power spectrum of cosmic microwave background
(CMB) lensing from two seasons of Atacama Cosmology Telescope Polarimeter
(ACTPol) CMB data. The CMB lensing power spectrum is extracted from both
temperature and polarization data using quadratic estimators. We obtain results
that are consistent with the expectation from the best-fit Planck LCDM model
over a range of multipoles L=80-2100, with an amplitude of lensing A_lens =
1.06 +/- 0.15 (stat.) +/- 0.06 (sys.) relative to Planck. Our measurement of
the CMB lensing power spectrum gives sigma_8 Omega_m^0.25 = 0.643 +/- 0.054;
including baryon acoustic oscillation scale data, we constrain the amplitude of
density fluctuations to be sigma_8 = 0.831 +/- 0.053. We also update
constraints on the neutrino mass sum. We verify our lensing measurement with a
number of null tests and systematic checks, finding no evidence of significant
systematic errors. This measurement relies on a small fraction of the ACTPol
data already taken; more precise lensing results can therefore be expected from
the full ACTPol dataset.Comment: 17 pages, 11 figures, to be submitted to Physical Review
Georgia Abortion Law and Our Commitment to Patients
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/153775/1/art41143.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/153775/2/art41143_am.pd
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