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We present an overview of the National Science Foundation’sDaniel K. Inouye Solar Telescope(DKIST), its instruments, and support facilities. The 4 m aperture DKIST provides the highest-resolution observations of the Sun ever achieved. The large aperture of DKIST combined with state-of-the-art instrumentation provide the sensitivity to measure the vector magnetic field in the chromosphere and in the faint corona, i.e. for the first time with DKIST we will be able to measure and study the most important free-energy source in the outer solar atmosphere – the coronal magnetic field. Over its operational lifetime DKIST will advance our knowledge of fundamental astronomical processes, including highly dynamic solar eruptions that are at the source of space-weather events that impact our technological society. Design and construction of DKIST took over two decades. DKIST implements a fast (f/2), off-axis Gregorian optical design. The maximum available field-of-view is 5 arcmin. A complex thermal-control system was implemented in order to remove at prime focus the majority of the 13 kW collected by the primary mirror and to keep optical surfaces and structures at ambient temperature, thus avoiding self-induced local seeing. A high-order adaptive-optics system with 1600 actuators corrects atmospheric seeing enabling diffraction limited imaging and spectroscopy. Five instruments, four of which are polarimeters, provide powerful diagnostic capability over a broad wavelength range covering the visible, near-infrared, and mid-infrared spectrum. New polarization-calibration strategies were developed to achieve the stringent polarization accuracy requirement of 5×10−4. Instruments can be combined and operated simultaneously in order to obtain a maximum of observational information. Observing time on DKIST is allocated through an open, merit-based proposal process. DKIST will be operated primarily in “service mode” and is expected to on average produce 3 PB of raw data per year. A newly developed data center located at the NSO Headquarters in Boulder will initially serve fully calibrated data to the international users community. Higher-level data products, such as physical parameters obtained from inversions of spectro-polarimetric data will be added as resources allow.

The citizen Continental-America Telescopic Eclipse (CATE) Experiment was a new type of citizen science experiment designed to capture a time sequence of white-light coronal observations during totality from 17:16 to 18:48 UT on 2017 August 21. Using identical instruments the CATE group imaged the inner corona from 1 to 2.1 RSun with 1.″43 pixels at a cadence of 2.1 s. A slow coronal mass ejection (CME) started on the SW limb of the Sun before the total eclipse began. An analysis of CATE data from 17:22 to 17:39 UT maps the spatial distribution of coronal flow velocities from about 1.2 to 2.1 RSun, and shows the CME material accelerates from about 0 to 200 km s−1 across this part of the corona. This CME is observed by LASCO C2 at 3.1–13 RSun with a constant speed of 254 km s−1. The CATE and LASCO observations are not fit by either constant acceleration nor spatially uniform velocity change, and so the CME acceleration mechanism must produce variable acceleration in this region of the corona.

This paper discusses the issues of processing life data containing zero-time failures, which are often the result of out-of-box, assembly line, screen test or other types of failure that occur before a product begins its field operation. Processing these zero-time failures can be a challenging task, since most statistical distributions and analysis software packages do not handle zero time values well. Therefore it is important for the analyst to have a good understanding of the data, including failure modes, data sources, mode of fault detection, and the product’s design and manufacturing process. This paper discusses real life situations with zero-time failures and suggests different approaches to handling such data. Examples and case studies are provided for each analysis method.

Last minute design changes after already completed product validation testing is a common occurrence in the engineering world. It is also common for a redesigned product to be retested to demonstrate compliance with the original reliability requirements. Therefore, there is often a question of how to demonstrate the required reliability metrics without repeating already completed test flow on a redesigned product. This article discusses the application of Bayesian techniques to reduce the sample sizes required for retesting of engineering products/systems after design modification. This method utilizes attribute test data collected on previous version(s) of the product via success-based testing prior to the design change occurrence. The proposed method helps to reduce the test sample size for attribute testing while demonstrating the required reliability and helping to reduce the overall cost of a product development cycle.

The Daniel K. Inouye Solar Telescope (DKIST), formerly Advanced Technology Solar Telescope when it begins operation in 2019 will be by a significant margin Earth's largest solar research telescope. Science priorities dictate an initial suite of instruments that includes four spectro-polarimeters. Accurate polarization calibration of the individual instruments and of the telescope optics shared by those instruments is of critical importance. The telescope and instruments have been examined end-to-end for sources of polarization calibration error, allowable contributions from each of the sources quantified, and techniques identified for calibrating each of the contributors. Efficient use of telescope observing time leads to a requirement of sharing polarization calibrations of common path telescope components among the spectro-polarimeters and for those calibrations to be repeated only as often as dictated by degradation of optical coatings and instrument reconfigurations. As a consequence the polarization calibration of the DKIST is a facility function that requires facility wide techniques.

The 4m Advance Technology Solar Telescope (ATST) is under construction on Maui, HI. With its unprecedented resolution and photon collecting power ATST will be an ideal tool for studying prominences and filaments and their role in producing Coronal Mass Ejections that drive Space Weather. The ATST facility will provide a set of first light instruments that enable imaging and spectroscopy of the dynamic filament and prominence structure at 8 times the resolution of Hinode. Polarimeters allow high precision chromospheric and coronal magnetometry at visible and infrared (IR) wavelengths. This paper summarizes the capabilities of the ATST first-light instrumentation with focus on prominence and filament science.

We provide an update on the construction status of the Daniel K. Inouye Solar Telescope. This 4-m diameter facility is designed to enable detection and spatial/temporal resolution of the predicted, fundamental astrophysical processes driving solar magnetism at their intrinsic scales throughout the solar atmosphere. These data will drive key research on solar magnetism and its influence on solar winds, flares, coronal mass ejections and solar irradiance variability. The facility is developed to support a broad wavelength range (0.35 to 28 microns) and will employ state-of-the-art adaptive optics systems to provide diffraction limited imaging, resolving features approximately 20 km on the Sun. At the start of operations, there will be five instruments initially deployed: Visible Broadband Imager (VBI; National Solar Observatory), Visible SpectroPolarimeter (ViSP; NCAR High Altitude Observatory), Visible Tunable Filter (VTF (a Fabry-Perot tunable spectropolarimeter); Kiepenheuer Institute for Solarphysics), Diffraction Limited NIR Spectropolarimeter (DL-NIRSP; University of Hawaii, Institute for Astronomy) and the Cryogenic NIR Spectropolarimeter (Cryo-NIRSP; University of Hawaii, Institute for Astronomy). As of mid-2016, the project construction is in its 4th year of site construction and 7th year overall. Major milestones in the off-site development include the conclusion of the polishing of the M1 mirror by University of Arizona, College of Optical Sciences, the delivery of the Top End Optical Assembly (L3), the acceptance of the Deformable Mirror System (Xinetics); all optical systems have been contracted and are either accepted or in fabrication. The Enclosure and Telescope Mount Assembly passed through their factory acceptance in 2014 and 2015, respectively. The enclosure site construction is currently concluding while the Telescope Mount Assembly site erection is underway. The facility buildings (Utility and Support and Operations) have been completed with ongoing work on the thermal systems to support the challenging imaging requirements needed for the solar research. Finally, we present the construction phase performance (schedule, budget) with projections for the start of early operations.

This paper presents a novel approach to predicting quantities of parts needed for a lifetime buy (LTB) prompted by technology obsolescence or production discontinuance in order to support a long term service contract. LTB is a critical business decision with serious consequences to a company's finances and its reputation, therefore accurate future demand modeling is very important. The forecasting method presented in this paper is based on a combination of factors including reliability and warranty data, demand expectations, penalty for unavailability of parts, aftermarket competition and a few others. The paper will introduce two new terms, demand attrition and demand retention, that describe the decrease in parts demand in the post-warranty period due to aftermarket and non-authentic parts alternatives. The application of the attrition functions (reduction in product population and product demand) has proven to be an important tool to provide accurate estimates for the LTB quantity predictions. Product shipping history can be a source of data to derive the demand retention function, which will depend on the type of the product, warranty terms, and availability of supply alternatives. This paper also presents a case study of an automotive electronics radio after a supplier's notice of discontinuance for the main microprocessor. The implementation of this method at Delphi Electronics & Safety has saved thousands of dollars on the LTB parts inventory by improving the accuracy of forecasting.

Glacial landforms on Mauna Kea, Hawai'i, show that the summit area of the volcano was covered intermittently by ice caps during the Late Pleistocene. Cosmogenic 36 Cl dating of terminal moraines and other glacial landforms indicates that the last two ice caps, called Older Makanaka and Younger Makanaka, retreated from their maximum positions approximately 23 ka and 13 ka, respectively. The margins and equilibrium line altitudes of these ice caps on the remote, tropical Pacific island were nearly identical, which would seem to imply the same mechanism for ice growth. But modelling of glacier mass balance, combined with palaeotemperature proxy data from the subtropical North Pacific, suggests that the causes of the two glacial expansions may have been different. Older Makanaka air atop Mauna Kea was likely wetter than today and cold, whereas Younger Makanaka times were slightly warmer but significantly wetter than the previous glaciation. The modelled increase in precipitation rates atop Mauna Kea during the Late Pleistocene is consistent with that near sea level inferred from pollen data, which suggests that the additional precipitation was due to more frequent and/or intense tropical storms associated with eastward-moving cold fronts. These conditions were similar to modern La Nina (weak ENSO) conditions, but persisted for millennia rather than years. Increased precipitation rates and the resulting steeper temperature lapse rates created glacial conditions atop Mauna Kea in the absence of sufficient cooling at sea level, suggesting that if similar correlations existed elsewhere in the tropics, the precipitation-dependent lapse rates could reconcile the apparent difference between glacial-time cooling of the tropics at low and high altitudes. Copyright # 2008 John Wiley & Sons, Ltd.

AUDIENCE RESPONSE TECHNOLOGY (ART) has been widely adopted on college campuses, and prior research indicates that, on average, it receives positive evaluations from students. However, research has not yet examined how characteristics of students as learners influence their responses to ART. The current study examined aptitude for learning, objective learning (i.e., class performance), subjective learning (i.e., self-perceived learning), and conceptualizations of the learning process as influences on students' evaluation of ART. Students who had used ART over the course of a semester in one of three large lecture classes (N=703) completed surveys assessing their learning characteristics, perceptions of ART influence on their attendance, motivation, and learning, liking for ART, and evaluations of the course and instructor. Controlling for course and instructor evaluations, aptitude and objective learning were weakly but negatively associated with evaluations of ART and subjective learning was positively associated with evaluations of ART. Further, different conceptualizations of learning have distinctive associations with ART evaluations. Discussion focuses on the implications of these findings for instructors' use of ART.

In the past few years, audience response technology (ART) has been widely adopted on college campuses, and is especially popular among instructors of large lecture classes. Claims regarding ART’s benefits to students have received only limited empirical evaluation, and prior studies exhibit methodological limitations. The current study provides a multi-dimensional evaluation, utilizing a newly-developed measure, the Audience Response Technology Questionnaire (ART-Q). Data were provided at three points during a semester by undergraduate students (n = 854) who used ART in three large lecture university courses. Results indicate moderately positive evaluations of ART on some dimensions (e.g., ease of use, impact on attendance), with less positive evaluations on others (e.g., influence on preparation for class). These evaluations showed some variability across time of semester and course, but were not substantially affected by gender, ethnicity, or year in school. Findings are discussed with respect to the need for future research on instructors’ techniques for using ART and their influence on student perceptions and outcomes.

We report here results of a study on the influence of sample mass on isotope ratios and accuracy of 129 I/I determinations in the AMS system at PRIME Lab, Purdue U. Iodine from four samples, two coal-bed methane brines, one surface water sample and a blank, was extracted and precipitated as AgI, following established methods. The resulting samples were subdivided into four sequences of targets, containing between 1.5 and 0.1 mg of AgI. Beam currents for samples with masses above 0.3 mg did not show a dependence on mass, but fell off strongly for smaller masses. The resulting isotope ratios were within the instrumental error limits and did not vary with sample mass, but accuracy decreased for samples with masses below 0.3 mg. The results demonstrate that the presence of 5000 129 I atoms in the target is sufficient for making a successful AMS determination, a level considerably lower than for other methods used in mass spectrometry. The ability of producing reliable 129 I/I ratios from targets as small as 0.1 mg of AgI enlarges considerably the range of applications possible for this isotopic system.

Cosmogenic nuclide techniques are increasingly being utilized in geoscience research. For this it is critical to establish an effective, easily accessible and well defined tool for cosmogenic nuclide computations. We have been developing a web-based tool (WebCN) to calculate surface exposure ages and erosion rates based on the nuclide concentrations measured by the accelerator mass spectrometry. WebCN for 10 Be and 26 Al has been finished and published at http://www.physics.purdue.edu/primelab/for_users/rockage.html . WebCN for 36 Cl is under construction. WebCN is designed as a three-tier client/server model and uses the open source PostgreSQL for the database management and PHP for the interface design and calculations. On the client side, an internet browser and Microsoft Access are used as application interfaces to access the system. Open Database Connectivity is used to link PostgreSQL and Microsoft Access. WebCN accounts for both spatial and temporal distributions of the cosmic ray flux to calculate the production rates of in situ-produced cosmogenic nuclides at the Earth’s surface.

Our group is interested in evaluating early effects of dietary interventions on bone loss. Postmenopausal women lose bone following reduction in estrogen which leads to increased risk of fracture. Traditional means of monitoring bone loss and effectiveness of treatments include changes in bone density, which takes 6 months to years to observe effects, and changes in biochemical markers of bone turnover, which are highly variable and lack specificity. Prelabeling bone with 41Ca and measuring urinary 41Ca excretion with accelerator mass spectrometry provides a sensitive, specific, and rapid approach to evaluating effectiveness of treatment. To better understand 41Ca technology as a tool for measuring effective treatments on reducing bone resorption, we perturbed bone resorption by manipulating dietary calcium in rats. We used 3H-tetracycline (3H-TC) as a proxy for 41Ca and found that a single dose is feasible to study bone resorption. Suppression of bone resorption, as measured by urinary 3H-TC, by dietary calcium was observed in rats stabilized after ovariectomy, but not in recently ovariectomized rats.

176,178,180 Hf( 3 He, d) angular distributions and 176,178,180 Hf( α , t) spectra were measured using 32 MeV 3 He and 30 MeV α particles at the University of Rochester MP tandem van de Graaff accelerator laboratory. Reaction products were analyzed with an Enge split-pole magnetic spectrograph. New nuclear structure information is reported for each of the residual nuclides 177,179,181 Ta, and the systematic behavior of bands based on the 7 / 2 + [ 404 ] , 9 / 2 − [ 514 ] , 5 / 2 + [ 402 ] , 1 / 2 − [ 541 ] , 1 / 2 + [ 411 ] and 1 / 2 − [ 530 ] bands can now be observed. Some limited measurements of the same reactions on a target of 177 Hf, taken to facilitate identification of isotopic impurity peaks in the main spectra, provide useful new structure information and a proton separation energy for 178 Ta.

Measurements of cosmogenic 36Cl in terrestrial rocks provide quantitative information about exposure ages of landforms and surface features. The isotope dilution method for preparing 36Cl samples is now widely used because it allows 36Cl and Cl to be measured simultaneously on a single accelerator mass spectrometry target, increases the accuracy and precision of Cl determinations, and reduces rock sample size and laboratory work. In this paper we describe a new implementation of isotope dilution to 36Cl dating, report experimental data verifying the accuracy of this approach, and show how errors in the measured stable isotope ratio propagate to errors in exposure ages. Successful application of isotope dilution to 36Cl dating requires that Cl be retained during digestion. We performed extractions in a sealed acid-digestion bomb to prevent Cl losses and to reduce digestion times by more than 90%. Isotope dilution gives 36Cl/Cl values within 1σ of conventional (unspiked) values for 8 paired silicate samples, and gives Cl concentrations that are consistent with the ion specific electrode method for 14 of 17 silicate samples. Results from three spiked replicates of a carbonate sample are also consistent with the unspiked 36Cl/Cl, but we found that isotope dilution gives a more accurate estimate of native Cl concentration than the ion specific electrode method. We also prepared five limestone samples in open vessels in the presence of excess Ag+ to prevent volatilization of Cl. This method would permit processing of larger samples (the bomb's capacity is 5 g), and would be useful for samples with low concentration of Cl or low 36Cl/Cl when insoluble fluorides do not precipitate in the digestion vessel. Results from paired samples digested in both open and closed vessels suggest that open-vessel digestion is a reliable way of preparing spiked carbonate samples.

SPINOR is a new spectro-polarimeter that will serve as a facility instrument for the Dunn Solar Telescope at the National Solar Observatory. This instrument is capable of achromatic polarimetry over a very broad range of wavelengths, from 430 up to 1600 nm, allowing for the simultaneous observation of several visible and infrared spectral regions with full Stokes polarimetry. Another key feature of the design is its flexibility to observe virtually any combination of spectral lines, limited only by practical considerations (e.g., the number of detectors available, space on the optical bench, etc)., To appear in Solar Physics. Note: Figures are low resolution versions due to file size limitations

Super achromatic retarders and polychromatic modulators are required to meet the polarimetry specifications of the Daniel K. Inouye Solar Telescope. These components have been analyzed and toleranced using a birefringent polarization ray trace over wavelength and field of view.

Variations in 129I/127I ratios were used to trace terrestrial organic carbon (tDOC) across an estuary because (1) iodine is biophilic, up to 75% of total iodine in fresh and coastal marine waters partitions into organic iodine; (2) 129I/127I ratios in tDOC are greatly elevated over those from marine systems because atmospheric emissions of 129I from European nuclear fuel reprocessing facilities were mixed more quickly in the surface ocean, up to 500 m in a decade, than the terrestrial system, which mixed approximately 10 cm in 10 to 50 y; and (3) the oceanic contribution of 127I (50 to 65 ppb) to the ratio has a greater dilution effect than 127I from freshwater (0.5 to 40 ppb). Analytical techniques were developed for 129I/127I ratio determination in dissolved organic iodine (DOI) and the other iodine species, using dehydrohalogenation, anion chromatography, high-performance liquid chromatography, and accelerator mass spectrometry, to be applied to samples from Galveston Bay, Texas. Results indicate that 129I/127I ratios in DOI from terrestrial sources are elevated in the upper estuary up to salinity of about 20, similar to a behavior previously described for this estuary for stable isotopic signals for dissolved organic matter. 129I/127I ratios in the other iodine species, e.g., iodide and iodate, did not show this feature, indicating fast isotopic and chemical equilibration between the two isotopes among the different inorganic species in the estuary. These results thus provide proof of concept that 129I/127I-DOI can serve as a tracer for tDOC in the coastal zone.

Erosion patterns associated with glaciation of trunk and hanging valley systems in northern Sweden were investigated using cosmogenic nuclide 10Be apparent exposure ages and inferred nuclide inheritance. Sequences of samples taken across valleys known to have been covered repeatedly by the Fennoscandian ice sheet revealed two primary patterns of erosion. In Vavlavagge the exposure age pattern is consistent with >2 m of glacial erosion during the last glacial cycle along the entire profile. At Ravtasvaggi, Dievssavaggi and Alisvaggi, exposure ages in the valley bottom contrast with apparent exposure ages two to four times older on the valley sides. The older ages on the valley sides reflect cosmogenic nuclide inheritance due to limited (

This paper presents a new date for one of the oldest shellmounds of the central-south Brazilian coast. This date seems to confirm three previous results obtained from two other shellmounds in the same region and formerly seen as unreliable by the archaeological community. A charcoal sample from a coastal shellmound located in the state of Rio de Janeiro, Sambaqui do Algodao, was dated by C-14-AMS to 7860 +/- 80 years BP. Besides confirming the previous ones, this new date is pulling back, by some two thousand years the consensually accepted antiquity for, the initial settlement of the central-south Brazilian coast - around 6000 years BP. The geographical and chronological proximity of those archaeological sites suggest that the initial settlement of the coast would have begun in this region rather than in the nuclear area with denser concentrations of shellmounds further to the South. It also strengthens the evidence of the possible route used by inland hunter-gatherers to reach this part of the coast. (C) 2004 Elsevier B.V. All rights reserved.

We study the time of settlement, period of occupation and the sociocultural system of the fishing-collecting groups, builders of huge shell and sand mounds found in the Brazilian coast. We present original results of four C-14 - AMS dates from the IBV4 archaeological site, one of the four sites of the Boa Vista group, located in Rio de Janeiro State, Brazil, and we analyze the occupation of the whole group. The results reaffirm the long occupation of populations in this region (similar to2400 yr). In this paper we complement the model proposed to this region, suggesting a discontinuous occupation of these sites, during two distinct periods: similar to4000-3300 yr BP and similar to2000-1500 yr BP. Moreover, it was possible to show that these sites were not active concomitantly, and that the occupation took place in an intermittent way. We show a strong correlation between the periods of occupation and of increasing sea level. (C) 2004 Elsevier B.V. All rights reserved.

We present results on radiocarbon dating of foraminifera shell samples, collected on the upper slope of Campos Basin, in Southern Brazil. This is the first time that the sedimentation rate of this area is measured with a fine scale (cm) stratigraphy. 14 C ages vary from (2560 ± 80) years. BP at the top to (7260 ± 80) years. BP at the bottom of the sediment column. The mean accumulation ratio for the whole column is (6.2 ± 0.7) cm/kyears.

The fundamentally geographic issue of the amounts and spatial patterns of erosion necessary to produce classic glacial landforms such as U-shaped valleys has been debated by scientists for over a century. Terrestrial cosmogenic nuclide (TCN) measurements in glacially abraded bedrock were used to determine patterns of glacial erosion and to quantify the amount of rock removed during the last glaciation along valley-side transects in Sinks Canyon, Wind River Range, Wyoming, and the South Yuba River, Sierra Nevada, California. Surface exposure ages from bedrock and erratic samples obtained during this study indicate last deglaciation between 13–18 ka in the South Yuba River and 15–17 ka in Sinks Canyon. These ages are in agreement with previously published glacial chronologies. In both areas, samples from valley cross sections revealed a pattern of erosion during the last glaciation that decreased toward the lateral limit of ice extent, as predicted by numerical models, while transects further upstream recorded >1.4 meters of bedrock removal throughout. The effects of varying interglacial erosion and surface exposure histories on modeled glacial erosion depths were tested, validating the methodology used. The results demonstrate that the TCN technique, applied at the valley scale, provides useful insight into the spatial pattern of glacial erosion. Extensive sampling in areas with limited erosional loss may provide detailed records of erosion patterns with which to test predictions generated by models of ice dynamics and erosion processes.

Scarp morphology evolution has commonly been used to estimate the timing of fault-scarp rupture events. However, rates of scarp degradation depend strongly on the geomorphic diffusivity, a parameter that is difficult to constrain independently. This difficulty may lead to large uncertainties in the estimated ages of rupture events. In this study, we have coupled the accumulation of the cosmogenic nuclide 36Cl to a model for scarp morphology in order to constrain the value of the geomorphic diffusivity and thus determine a more accurate rupture chronology than a rupture history based solely on scarp morphology. We measured depth profiles of 36Cl accumulated in situ within alluvial sediments beneath the surface of the Socorro Canyon fault scarp in central New Mexico. The material analyzed consisted of ∼150 individual gravel clasts from each depth interval, amalgamated into a single sample. The alluvium was sampled in three vertical profiles ∼4 m deep. The first profile was ∼1.5 m downslope of the fault plane on the hanging wall, the second ∼1.5 m upslope of the fault plane on the footwall, and the third ∼27 m upslope of the fault plane on the footwall. The third profile, which served as a control, and which soil geomorphic evidence indicated was beneath a stable surface, showed a simple exponential 36Cl profile from which a depositional age of 122±18 ka was calculated. The second profile (on the footwall) showed a 36Cl deficit relative to the control profile, indicating net erosion. The first profile (on the hanging wall) showed a 36Cl excess relative to the control profile, indicating net deposition. Stratigraphic evidence in the hanging wall indicated two rupture events prior to the Late Holocene. We modeled the accumulation of 36Cl in the vicinity of the scarp, simulating erosional redistribution using a diffusion equation for scarp morphology. The model accounted for redistribution of 36Cl along with the sediment and the effects of the changing fault-scarp morphology on the 36Cl production. By matching both the observed hanging-wall and footwall 36Cl profiles to profiles calculated by the model, as well as the observed topographic profile, we obtained ages of 92+16−13 and 28+18−23 ka for the two ruptures. The results of our study indicate that cosmogenic nuclides can be useful in constraining rupture chronologies of fault scarps in alluvium.

When using 36Cl to date very old groundwater in regional aquifer systems, knowledge of the subsurface 36Cl input into the aquifer system is essential. Although 36Cl can be produced through nuclear reactions in the subsurface, in many situations, the input of 36Cl into sedimentary aquifer systems by this avenue of production can be neglected. This is a valid assumption when investigating long-flowpath groundwater systems composed of sandstones, limestones, and shales of typical composition. These rock types are not sufficiently enriched in radioactive elements to produce significant 36Cl in the deep subsurface. Carbonaceous shales, on the other hand, can concentrate the radioactive elements necessary to produce significant 36Cl in the deep subsurface. Chlorine-36 ratios (36Cl/Cl) for a suite of Late Devonian and Pennsylvanian carbonaceous shales were calculated from bulk-rock chemistry as well as measured using accelerator mass spectrometry. The poor agreement between calculated and measured ratios is the result of the assumption of chemical homogeneity used by the calculation algorithm, an assumption that was not satisfied by the carbonaceous shales. In these shales, organic matter, clay minerals, and accessory minerals are heterogeneously distributed and are physically distinct on a micron-order scale. Although organic matter and clay minerals constitute the overwhelming bulk of the shales, it is the phosphate minerals that are most important in enhancing, and suppressing, 36Cl production. Minerals such as apatite and carbonate-apatite (francolite)—by including uranium, rare earth elements (REEs), and halogens—have an important impact on both neutron production and thermal neutron absorption. By incorporating both uranium and fluorine, phosphate minerals act as neutron production centers in the shale, increasing the probability of 36Cl production. By incorporating REEs and chlorine, phosphate minerals also act to shield 35Cl from the thermal neutron flux, effectively suppressing the production of 36Cl. To reconcile the measured 36Cl ratios with the ratios calculated assuming chemical homogeneity, the shales were artificially split into three fractions: organic, clay mineral, and phosphate mineral. Neutron production was calculated separately for each fraction, and the calculation results demonstrated that the phosphate fraction exerted much more control on the 36Cl ratio than the organic or clay mineral fractions. By varying the uranium and chlorine contents in the phosphate fraction, a new, heterogeneous 36Cl ratio was calculated that agreed with the measured ratio for the overwhelming majority of the carbonaceous shales. When using rock chemistry to calculate the 36Cl ratio, rock types that show mineralogical heterogeneity on a micron scale can be divided into bulk fractions and accessory fractions for separate calculations of neutron production and neutron absorption. In this manner, a more accurate, heterogeneous 36Cl ratio can be calculated for the rock as a whole.

The ability of accelerator mass spectrometry (AMS) to measure very small concentrations of the nuclides Be-10, C-14, Al-26, Cl-36, and I-129 has led to many innovative applications in geologic research. To take advantage of this opportunity in the geosciences, it is important to understand how AMS works, how these nuclides are produced, and how they can be applied to geologic problems. We first discuss the basics of AMS, explaining what gives the method its ability to count small numbers of these nuclides. We review how these nuclides are produced and transported in the atmosphere, hydrosphere, and lithosphere. We then explain the ways that AMS is being used to solve a wide range of problems in geologic research by discussing specific applications in areas such as geomorphology, tectonics, climatology, hydrology, and geochronology.

Cosmogenic radionuclide analysis for determining exposure ages and erosion rates is becoming more extensively utilized. Due to the complexity of the neutron absorption production avenue, the interpretation of 36Cl data is a complex problem, particularly for non-trivial landform geometries. This work provides a numerical, Monte Carlo simulation analysis of variations in in situ cosmogenic 36Cl production rate near the bottom of vertical cliffs. It is found that in comparison with production at height (more than a thermal neutron mean free path length in air) the production rate in the cliff face increases with decreasing height, but within a thermal neutron mean free path length in rock near the bottom of the cliff, the production rate exhibits a sharp decrease.

If the Pauli exclusion principle were violated, the electronic structure of Be could be 1s 4 (denoted by Be ′ ) rather than 1s 2 2s 2 . This paper describes the results of an experimental search for Be ′ , carried out at PRIME Lab, the Purdue Rare Isotope Measurement Laboratory. In the process of setting stringent constraints on Be ′ using samples of metallic Be, Be ore, natural gas, and air, we made several modifications to the PRIME Lab facility. These included a new Be-free source and the construction of a gas introduction system which coupled to the existing ion source. The modifications permitted us to reach limits which are a factor of nearly 300 better than those obtained in previous experiments.

Some areas within ice sheet boundaries retain pre-existing landforms and thus either remained as ice free islands (nunataks) during glaciation, or were preserved under ice. Differentiating between these alternatives has significant implications for paleoenvironment, ice sheet surface elevation, and ice volume reconstructions. In the northern Swedish mountains, in situ cosmogenic 10Be and 26Al concentrations from glacial erratics on relict surfaces as well as glacially eroded bedrock adjacent to these surfaces, provide consistent last deglaciation exposure ages (∼8–13 kyr), confirming ice sheet overriding as opposed to ice free conditions. However, these ages contrast with exposure ages of 34–61 kyr on bedrock surfaces in these same relict areas, demonstrating that relict areas were preserved with little erosion through multiple glacial cycles. Based on the difference in radioactive decay between 26Al and 10Be, the measured nuclide concentration in one of these bedrock surfaces suggests that it remained largely unmodified for a minimum period of 845−418+461 kyr. These results indicate that relict areas need to be accounted for as frozen bed patches in basal boundary conditions for ice sheet models, and in landscape development models. Subglacial preservation also implies that source areas for glacial sediments in ocean cores are considerably smaller than the total area covered by ice sheets. These relict areas also have significance as potential long-term subglacial biologic refugia.

Pleistocene fluvial landforms and riparian ecosystems in central California responded to climate changes in the Sierra Nevada, yet the glacial history of the western Sierra remains largely unknown. Three glacial stages in the northwestern Sierra Nevada are documented by field mapping and cosmogenic radionuclide surface-exposure (CRSE) ages. Two CRSE ages of erratic boulders on an isolated till above Bear Valley provide a limiting minimum age of 76,400±3800 10Be yr. Another boulder age provides a limiting minimum age of 48,800±3200 10Be yr for a broad-crested moraine ridge within Bear Valley. Three CRSE ages producing an average age of 18,600±1180 yr were drawn from two boulders near a sharp-crested bouldery lateral moraine that represents an extensive Tioga glaciation in Bear Valley. Nine CRSE ages from striated bedrock along a steep valley transect average 14,100±1500 yr and suggest rapid late-glacial ice retreat from lower Fordyce Canyon with no subsequent extensive glaciations. These ages are generally consistent with glacial and pluvial records in east-central California and Nevada.

We discus here the prehistoric settlement of the central-south Brazilian coast, and, more specifically, 1 old radiocarbon date obtained for a costal shellmound, as well as its implications concerning the chronology attributed to the settlement process. The accelerator mass spectrometry (AMS) technique was used to determine the 14C age of charcoal from a shellmound on the southern coast of Rio de Janeiro. The resulting age was 7860 ± 80 BP, an unexpected result that reinforces 2 similar previously obtained dates for the same region. Brazilian archaeologists, however, have questioned those 2 dates, because they would predate by some 2000 yr the antiquity consensually accepted for the settlement of the central-south Brazilian littoral.

The Daniel K. Inouye Solar Telescope is a 4-meter-class all-reflecting telescope under construction on Haleakalā mountain on the island of Maui, Hawai’i. When fully operational in 2019 it will be the world's largest solar telescope with wavelength coverage of 380 nm to 28 microns and advanced Adaptive Optics enabling the highest spatial resolution measurements of the solar atmosphere yet achieved. We review the first-generation DKIST instrument designs, select critical science program topics, and the operations and data handling and processing strategies to accomplish them.

The Daniel K. Inouye Solar Telescope (formerly Advanced Technology Solar Telescope) will be the world's largest solar telescope and polarimeter when completed in 2019. Efficient use of the telescope to address key science priorities calls for polarization measurements simultaneously over broad wavelength ranges and calibration of the telescope and polarimeters to high accuracy. Broadband polarization modulation and calibration optics utilizing crystal optics have been designed for this application. The performance of polarization modulators and calibration retarders is presented along with a discussion of the unique challenges of this application. Polarimeters operate over the ranges of 0.38-1.1 microns, 0.5-2.5 microns, and 1.0-5.0 microns. Efficient polarization modulation over these broad ranges led to modulators utilizing multiple wave plates and that are elliptical, rather than linear, retarders. Calibration retarders are linear retarders and are constructed from the same sub-component wave plate pairs as the polarization modulators. Polarization optics must address efficiency over broad wavelength ranges while meeting beam deflection, transmitted wave front error, and thermal constraints and doing so with designs that, though large in diameter, can be affordably manufactured.

The objectives of our study were to estimate the percentage of aluminum (Al) that enters the brain, the half-life of brain Al, and the ability of an Al chelator to reduce brain Al. Rats received an iv infusion of Al transferrin, the primary Al species in plasma, or Al citrate, the predominant small molecular weight Al species in plasma. The infusion contained approximately 0.2-0.3 nCi (0.4-0.6 nmol) (26)Al, enabling the study of Al distribution into and retention by the brain at physiological Al concentrations. Some Al transferrin-infused rats received ip injections of the Al chelator desferrioxamine (DFO), 0.15 mmol/kg, three times weekly. The others received saline injections. The rats were euthanized from 4 hr to 4 days (Al citrate) or 256 days (Al transferrin) later. Brain (26)Al was determined by accelerator mass spectrometry. Peak brain (26)Al concentration was approximately 0.005% of the (26)Al dose in each gram of brain, irrespective of Al species administered. In the absence of DFO treatments, brain (26)Al concentration decreased with a half-life of approximately 150 days. The brain Al half-life in the DFO-treated rats was approximately 55 days. The results show a small fraction of Al in blood enters the brain, where it persists for a long time. The ability of repeated DFO treatments to modestly accelerate the reduction of brain Al is consistent with the necessity of prolonged DFO therapy to significantly reduce Al-induced dialysis encephalopathy.

The rate of in vivo degradation was determined for a naturally occurring biomaterial derived from the extracellular matrix of the small intestinal submucosa (SIS). The SIS was labeled by giving weekly intravenous injections of 10 microCi of 14C-proline to piglets from 3 weeks of age until the time of sacrifice at 26 weeks. The resultant SIS prepared from these pigs contained approximately 10(3) fold more 14C than unlabeled tissues. The labeled SIS was used to repair experimental defects in the urinary bladder of 10 dogs. The animals were sacrificed at post-operative times ranging from 3 days to 1 year and the remodeled urinary bladder tissue was harvested for evaluation of 14C by a combination of liquid scintillation counting and accelerator mass spectrometry. The remodeled tissue contained less than 10% of the 14C (disintegrations per minute/gram tissue wet weight) at 3 months post-surgery compared to the SIS biomaterial that was originally implanted. The SIS scaffold was replaced by host tissue that resembled normal bladder both in structure and function. After implantation, 14C was detected in highest concentrations in the blood and the urine. The SIS bioscaffold provides a temporary scaffold for tissue remodeling with rapid host tissue remodeling, degradation, and elimination via the urine when used as a urinary bladder repair device.

The objectives were to estimate aluminum (Al) oral bioavailability under conditions that model its consumption in drinking water, and to test the hypotheses that stomach contents and co-administration of the major components of hard water affect Al absorption. Rats received intragastric 26Al in the absence and presence of food in the stomach and with or without concomitant calcium (Ca) and magnesium (Mg) at concentrations found in hard drinking water. The use of 26Al enables the study of Al pharmacokinetics at physiological Al concentrations without interference from 27Al in the environment or the subject. 27Al was intravenously administered throughout the study. Repeated blood withdrawal enabled determination of oral 26Al bioavailability from the area under its serum concentrationxtime curve compared to serum 27Al concentration in relation to its infusion rate. Oral Al bioavailability averaged 0.28%. The presence of food in the stomach and Ca and Mg in the water that contained the orally dosed 26Al appeared to delay but not significantly alter the extent of 26Al absorption. The present and published results suggest oral bioavailability of Al from drinking water is very low, about 0.3%. The present results suggest it is independent of stomach contents and water hardness.

Processing and measurement of 200 biomedical samples has provided an opportunity to better understand the characteristics of accelerator mass spectrometry (AMS) analysis of such samples. We have utilized established procedures (Vogel 1992) and developed new methods for handling various biological samples. We have included secondary standards of known isotope ratio for all assays. A method of determining maximum precision for each unknown sample value is also reported. The presented data are an update of the ongoing radiocarbon AMS biomedical program at Purdue University.

The new technique of tandem accelerator mass spectrometry (TAMS) has improved the sensitivity for measurement of several long-lived radioisotopes and certain stable isotopes by many orders of magnitude. Nuclear physics tandems and new small dedicated accelerators are now able to measure(14)C,(10)Be,(26)Al,(32)Si,(36)Cl,(41)Ca, and(129)I in natural materials. Sensitivities down to 10(5) atoms per sample can be achieved in favorable cases. By accelerating ions to MeV energies, one can eliminate molecules and uniquely identify the atomic numbers below 20. Although most applications to date have been in the earth sciences, the opportunity now exists for important new applications in biology and toxicology. Trace elements can be measured at the parts per billion (10(9)) level using a secondary ion mass spectrometry (SIMS) ion source. Radioactive tracer measurements can be made for elements, such as aluminum, for which there are no isotopes with suitable half-lives for conventional decay counting methods. For(14)C, counting times become much shorter and dose levels can be reduced.

The biomedical accelerator mass spectrometry (AMS) initiative at PRIME Lab including the status of equipment and sample preparation is described. Several biomedical projects are underway involving one or more of the nuclides: 14C, 26Al and 41Ca. Routine production of CaF2 and graphite is taking place. Finally, the future direction and plans for improvement of the biomedical program at PRIME Lab are discussed.

The Purdue Rare Isotope Measurement Laboratory (PRIME Lab) is a dedicated research and service facility for AMS that provides the scientific community with timely, reliable and high quality chemical processing (∼600 samples/year) and AMS measurements (∼3000 samples/year) of 10 Be, 14 C, 26 Al, 36 Cl, 41 Ca and 129 I. The AMS system is based on an upgraded FN (7 MV) tandem accelerator that has recently been modified to improve performance. The precision is 1% for 14 C and it is 3–5% for the other nuclides for radioisotope/stable isotope ratios at the 10 −12 levels. System background for 10 Be, 14 C, 26 Al, 36 Cl and 41 Ca is 1–10×10 −15 while for 129 I the natural abundance limits it to 20×10 −15 . Research is being carried out in Earth, planetary, and biomedical sciences. Geoscience applications include determination of exposure ages of glacial moraines, volcanic eruptions, river terraces, and fault scarps. Burial histories of sand are being determined to decipher the timing of human expansion and climatic history. Environmental applications are tracing the release of radioactivity from nuclear fuel reprocessing plants, water tracing, and neutron dosimetry. The applications using meteoric nuclides are oil field brines, sediment subduction, radiocarbon dating, and groundwater 36 Cl mapping. Radionuclide concentrations are also determined in meteorites and tektites for deciphering space and terrestrial exposure histories.

Quantitative information on the uptake and distribution of Al at the cellular level is required to understand mechanisms of Al toxicity, but direct measurement of uptake across the plasma membrane has remained elusive. We measured rates of Al transport across membranes in single cells of Chara corallina using the rare26Al isotope, an emerging technology (accelerator mass spectrometry), and a surgical technique for isolating subcellular compartments. Accumulation of Al in the cell wall dominated total uptake (71–318 μg m−2 min−1), although transport across the plasma membrane was detectable (71–540 ng m−2 min−1) within 30 min of exposure. Transport across the tonoplast was initially negligible, but accelerated to rates approximating uptake across the plasma membrane. The avacuolate protoplasm showed signs of saturation after 60 min, but continued movement across the plasma membrane was supported by sequestration in the vacuole. Saturation of all compartments was observed after 12 to 24 h. Accumulation of Al in the cell wall reflected variation in {Al3+} induced by changes in Al supply or complexing ligands, but was unaffected by pH. In contrast, transport across the plasma membrane peaked at pH 4.3 and increased when {Al3+} was reduced by complexing ligands. Cold temperature (4°C) reduced accumulation in the cell wall and protoplasm, whereas 2,4-dinitrophenol andm-chlorocarbonylcyanidephenyl hydrazone increased membrane transport by 12- to 13-fold. Our data suggest that the cell wall is the major site of Al accumulation. Nonetheless, membrane transport occurs within minutes of exposure and is supported by subsequent sequestration in the vacuole. The rapid delivery of Al to the protoplasm suggests that intracellular lesions may be possible.

A small quantity of aluminum chlorohydrate (ACH), the active ingredient in antiperspirants, was labeled with the radioisotope 26Al. This labeled drug will be used in future studies to measure the absorption of aluminum from antiperspirant use. The purpose of this study was to demonstrate that the technique used to make the 26Al-labeled ACH resulted in a uniformly labeled complex, and therefore any measurement of 26Al would be indicative of total aluminum. The labeled ACH was fractionated using gel filtration chromatography into 72 evenly spaced samples. The fractions were then measured for 26Al and total aluminum content using accelerator mass spectrometry (AMS) and inductively coupled plasma atomic emission spectroscopy (ICP-AES). Results indicate that the ACH is uniformly labeled.

The extent of glaciation at the northern margin of the Canadian/Greenland high-latitude Arctic region over the past 30,000 years is uncertain. Geological arguments have been made for Greenland and Ellesmere Island ice sheets that coalesced to block the Nares Strait1, and for restricted ice sheets on the two islands2 leaving the strait open, as it is today3. Distinguishing between these two possibilities would provide significant constraints on present understanding of the past circulation between the Arctic and Atlantic oceans4,5, on estimates of past ice-volume6, and on the response of the Greenland ice sheet to climate change7. Radiocarbon analyses provide dates for the deglaciation of the islands' coasts, but do not yield information on whether ice filled the strait. Here we present measurements of cosmogenic 36Cl that has accumulated in situ in erratics and glacially polished bedrock on islands within the Nares Strait. These data allow us to determine the time for which the rocks have been recently exposed to the atmosphere, and thus the age of the final deglaciation of the strait. We show that Greenland and Ellesmere ice sheets retreated from the Nares Strait about 10,000 years ago. The strait was filled with ice during the last glaciation, blocking this connection between the Arctic and Atlantic oceans, and supporting the model of extensive and long-lasting ice on land and sea in this region8,9,10,11.

The decrease in rates of production of cosmogenic nuclides occurs because of shielding of cosmic rays by mountains, sloped surfaces, and local rock formations that block them. When a large part of the sky is blocked, this correction is large and requires detailed model calculations. This paper considers three geometries: a rectangular obstruction, a triangular obstruction, and a sloped surface. Other geometries can be considered as a combination of these. The results are presented in terms of formulas and graphs so that the reader can easily apply them to common field situations. Any use of cosmogenic nuclides in the study of geomorphic processes or forms must consider factors that introduce variations in the production of nuclides.

This paper presents first observations of dynamics of the white-light solar corona detected during the few minutes of totality of a solar eclipse. Perturbations of a polar plume associated with an embedded ‘jet’ structure observed simultaneously at 195 A with the EUV Imaging Telescope (EIT) aboard the SOHO spacecraft lead to estimates of the electron density fluctuations accompanying the jet: ±15%. The morphological behavior of the jet, its apparent upward propagation speed of ≈ 200 km s−1, and the inferred density perturbations suggest that the jet is led by a weak, outward-propagating shock resulting from the injection of material at high velocity at the base of the corona. Smaller perturbations of the white-light corona are apparent at many other locations, sustaining hope that propagating Alfven waves may be measurable in the solar corona. Density perturbations associated with the jet follow from empirical electron density models of the polar inter-plume and plume regions, as derived from the ground-based eclipse measurements of coronal polarization brightness. These models indicate polar plume densities 4–6 times that of the interplume low corona.

PRIME Lab has a multidisciplinary external research program with projects in geomorphology, hydrology, ocean science, planetary science, environmental science and biology.

The operation, status, performance, and upgrade plans for the Purdue Rare Isotope Measurement Laboratory (PRIME Lab) are described. The AMS system is in routine operation for all of the commonly-used AMS nuclides. Chemical preparation is being performed for all nuclides measured in many different matrices. Construction of a new injector and terminal stripper system is in progress; a fast-isotope-switching system is in the final design stage.