Abstract
We present the first measurements of asteroids in millimeter wavelength data from the South Pole Telescope (SPT), which is used primarily to study the cosmic microwave background (CMB). We ...analyze maps of two ∼270 deg
2
sky regions near the ecliptic plane, each observed with the SPTpol camera ∼100 times over 1 month. We subtract the mean of all maps of a given field, removing static sky signal, and then average the mean-subtracted maps at known asteroid locations. We detect three asteroids—(324) Bamberga, (13) Egeria, and (22) Kalliope—with signal-to-noise ratios (S/N) of 11.2, 10.4, and 6.1, respectively, at 2.0 mm (150 GHz); we also detect (324) Bamberga with an S/N of 4.1 at 3.2 mm (95 GHz). We place constraints on these asteroids’ effective emissivities, brightness temperatures, and light-curve modulation amplitude. Our flux density measurements of (324) Bamberga and (13) Egeria roughly agree with predictions, while our measurements of (22) Kalliope suggest lower flux, corresponding to effective emissivities of 0.64 ± 0.11 at 2.0 and < 0.47 at 3.2 mm. We predict the asteroids detectable in other SPT data sets and find good agreement with detections of (772) Tanete and (1093) Freda in recent data from the SPT-3G camera, which has ∼10× the mapping speed of SPTpol. This work is the first focused analysis of asteroids in data from CMB surveys, and it demonstrates we can repurpose historic and future data sets for asteroid studies. Future SPT measurements can help constrain the distribution of surface properties over a larger asteroid population.
Time-division multiplexing (TDM) is the backup readout technology for the X-ray Integral Field Unit (X-IFU), a 3168-pixel X-ray transition-edge sensor (TES) array that will provide imaging ...spectroscopy for european space agency's Athena satellite mission. X-IFU design studies are considering readout with a multiplexing factor of up to 40. We present data showing 40-row TDM readout (32 TES rows + 8 repeats of the last row) of TESs that are of the same type as those being planned for X-IFU, using measurement and analysis parameters within the ranges specified for X-IFU. Single-column TDM measurements have best-fit energy resolution of (1.91 ± 0.01) eV for the Al Kα complex (1.5 keV), (2.10 ± 0.02) eV for Ti Kα (4.5 keV), (2.23 ± 0.02) eV for Mn Kα (5.9 keV), (2.40 ± 0.02) eV for Co Kα (6.9 keV), and (3.44 ± 0.04) eV for Br Kα (11.9 keV). Three-column measurements have best-fit resolution of (2.03 ± 0.01) eV for Ti Kα and (2.40 ± 0.01) eV for Co Kα. The degradation due to the multiplexed readout ranges from 0.1 eV at the lower end of the energy range to 0.5 eV at the higher end. The demonstrated performance meets X-IFU's energy-resolution and energy-range requirements. True 40-row TDM readout, without repeated rows, of kilopixel scale arrays of X-IFU-like TESs is now under development.
Strontium concentration and isotope composition (
87Sr/
86Sr) are important proxies for tracing solute and suspended load origins in surface water systems, but have not been widely applied to lakes. ...We determined these proxies, in addition to major ion compositions, in waters collected from Lake Texoma, a large crescent-shaped (concave-west) impoundment on the border of Texas and Oklahoma that marks the downstream culmination of the Upper Red River Basin (URRB), and its major influent rivers. These rivers enter the lake at its southerly and northerly arms and have distinctly different salinities and discharges, respectively: the more saline Red River (mean total dissolved solids, TDS
=
2930
mg/L; 1290
mg/L weighted for discharge, Gainesville gauging station) and the fresher Washita River (TDS
=
634
mg/L; 376
mg/L weighted for discharge, Dickson gauging station). These two influent river systems combine to mix in the deepest (main) part of the lake. The URRB involves a heterogeneous mix of bedrock geologies, notably high solubility Permian marine evaporites (gypsum, halite) and carbonates, and riverine solute load and composition can vary accordingly with regional precipitation. Most river and lake waters show an strong positive correlation between
87Sr/
86Sr and 1/Sr. Red River system waters have variable
87Sr/
86Sr values, ranging from 0.7076 to 0.7097 (n
=
34), whereas the Washita River system appears to be less isotopically variable, with
87Sr/
86Sr values ranging from 0.7082 to 0.7087 (n
=
16). Lake Texoma
87Sr/
86Sr varies spatially between 0.7087 and 0.7092, reflecting mixing of the two input rivers. Variations in Sr isotope composition, Ca/Na and Sr/Ca of river and lake waters are consistent with the majority of the solute load being derived from dissolution of Permian marine chemical sediments, dominantly halite with lesser gypsum. Waters with Sr isotope composition more radiogenic than Permian seawater reflect the contribution of Permian and Pennsylvanian siliciclastic sediments in the case of the Red River watershed, and Precambrian granite in the Washita River watershed. In the main lake water column, Sr concentrations and filtered
87Sr/
86Sr increase substantially with depth during summer stratification (from 0.7087 to 0.7091), likely reflecting desorption of Sr from suspended solid surfaces and breakdown of oxyhydroxides below the metalimnion. The differences in
87Sr/
86Sr between filtered and unfiltered aliquots suggest that Sr associated with the suspended load (calcite) is either less radiogenic than the dissolved load or more radiogenic than surface waters but only released to the dissolved pool under deeper reducing conditions below the metalimnion. Either possibility has important implications for Sr cycling in binary mixing models and paleolake reconstruction from Sr isotopes.
►
87Sr/
86Sr & major ion ratios indicate halite and gypsum dissolution in the watershed. ► Sr (mg/L) and filtered
87Sr/
86Sr increase with depth during summer stratification. ► Increase reflects desorption of Sr & breakdown of oxyhydroxides below the metalimnion. ►
87Sr/
86Sr more radiogenic in filtered than unfiltered aliquots below the metalimnion. ► Suspended load (calcite) is therefore less radiogenic than the dissolved load.
A method was developed for the analysis of vitamins D2 and D3 in a variety of nutritional products. To extract vitamins D2 and D3 from products containing substantial amounts of fat, a saponification ...with alcoholic potassium hydroxide is required to release the vitamin D. Trideuterium-labeled vitamin D is added to the sample prior to saponification, and quantitation is achieved using linear regression of the ratio of peak response for 2H3-D and vitamin D. Acceptable linearity was achieved between 0.6 and 27 microg/100 g with a correlation requirement of >0.999. The method detection limit of 0.02 microg/100 g was verified by spiking placebo products carried through the saponification and extraction steps of the method. At the quantitation limit (0.12 microg/100 g), the signal was easily distinguished from the background. Vitamin D3 spike recoveries ranged from 107 to 119% at the low level and 104 to 116% at the high-level spike. Vitamin D2 recoveries were 105 to 116% and 91 to 110% for the low- and high-level spikes, respectively. SRM 1849a has a certified concentration of 11.1 +/- 1.7 microg/100 g; using this standard reference material, the range of 9.4 to 12.8 microg/100 g was met on each of the 6 days. Method repeatability, determined in 12 vitamin D3 product matrixes over 6 days, ranged from 3.9 to 48%. The adult nutrition-milk protein sample was the most notable; it failed within-day, as well as day-to-day, precision requirements. There was no attempt to optimize the sample preparation to accommodate any problem matrix.
During the "Standards Development and International Harmonization: AOAC INTERNATIONAL Mid-Year Meeting" held on June 29, 2011, an Expert Review Panel (ERP) on behalf of AOAC INTERNATIONAL adopted the ...method "Simultaneous Determination of Vitamins D2 and D3 by LC-MS/MS in Infant Formula and Adult Nutritionals" as an AOAC Official First Action method. Vitamins D2 and D3 are extracted from the sample using pentane-ether; the extract is collected and dried under nitrogen. Vitamin D is separated from interfering compounds using UPLC, and quantitated using tandem mass spectrometry (MS/MS). Preliminary data showed the intermediate precision ranged from 3.34-8.05% and an accuracy range of 98.5-111% over the samples tested for vitamin D3. For vitamin D2, the intermediate precision ranged from 2.37-5.45% and accuracy ranged from 96.4-104% over the four matrixes evaluated. The analytical range for the method is bounded by the concentrations of the working standards, 21-270 ng/mL, and is equivalent to 0.168-2.16 mcg/100 g in ready-to-feed product. The practical method quantitation limit is 0.168 mcg/100 g product with method detection limit of 60 ng/100 g product. The ERP reviewed the data and determined that the performance characteristics of the method met the standard method performance requirements, and therefore the method was granted First Action status.
Data from a previously published study in J. AOAC Int. 91,130-142 (2008) was presented to the Stakeholder Panel on Infant Formula and Adult Nutritionals (SPIFAN) during the AOAC Annual Meeting held ...in Las Vegas, NV, from September 30 to October 3, 2012. The panel reviewed the data submitted and concluded that the method satisfied the standard method performance requirements established by SPIFAN. Based on this information, the panel approved the method as AOAC First Action. The determination of free carnitine involves dilution and filtration of the sample, followed by determination of L-carnitine by LC/MS/MS. The determination of total carnitine includes a saponification procedure prior to dilution and filtration.
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