Evaluating the Roles of Rainout and Post-Condensation Processes in a Landfalling Atmospheric River with Stable Isotopes in Precipitation and Water Vapor

Atmospheric rivers (ARs), and frontal systems more broadly, tend to exhibit prominent “V” shapes in time series of stable isotopes in precipitation. Despite the magnitude and widespread nature of these “V” shapes, debate persists as to whether these shifts are driven by changes in the degree of rainout, which we determine using the Rayleigh distillation of stable isotopes, or by post-condensation processes such as below-cloud evaporation and equilibrium isotope exchange between hydrometeors and surrounding vapor. Here, we present paired precipitation and water vapor isotope time series records from the 5–7 March 2016, AR in Bodega Bay, CA. The stable isotope composition of surface vapor along with independent meteorological constraints such as temperature and relative humidity reveal that rainout and post-condensation processes dominate during different portions of the event. We find that Rayleigh distillation controls during peak AR conditions (with peak rainout of 55%) while post-condensation processes have their greatest effect during periods of decreased precipitation on the margins of the event. These results and analyses inform critical questions regarding the temporal evolution of AR events and the physical processes that control them at local scales

Wild Bactrian Camel Conservation

The wild Bactrian camel (Camelus bactrianus ferus) is critically endangered throughout its range in China and Mongolia. Yet, wild camels remain poorly understood, with knowledge derived primarily from a few short studies and anecdotal information. We initiated a wild camel conservation project to determine the reasons for camel decline and to develop a program to address those problems. We are employing satellite telemetry to gather data on wild camel movement patterns, home ranges, habitat use, and sources of mortality. We are also collecting feces from camels and wolves to determine important forage plants and to begin to assess predation levels, respectively. In addition, steroid fecal analysis may help us evaluate wild camel reproductive physiology. Finally, we are directly observing wild camels to study their behavior. Thus far, we successfully collared two wild camels (one male, one female). We received one year’s data on the cow before her Doppler satellite collar failed and are receiving only sporadic data from the GPS satellite collar on the bull. Over one year, the cow covered a minimum distance of 4,527 km and her 100% minimum convex polygon (MCP) home range was 17,232 km2. Her kernel home range sizes covered 8,696 km2 for 95%, 4,031 km2 for 75%, 2,284 km2 for 55%, and 612 km2 for 25% kernels. We received only 20 GPS locations on our bull from October 10, 2003 to March 22, 2004. During that time, he travelled a minimum of 683 km and his 100% MCP home range extended over 9,191 km2. His kernel home ranges covered 7,255 km2 for the 95%, 3,741 km2 for the 75%, 1,346 km2 for the 50%, 585 km2 for the 25%, and 115 km2 for the 5% kernel. Over the past few autumns, mean group size was 10.07±1.82 wild camels/group. We are currently analyzing the behavioral data and plan to evaluate the fecal samples once we have sufficient samples. We hope to use the knowledge derived from our work to develop a proactive conservation program working in close cooperation with the Mongolian government and other scientists and conservationists

Analysis of Noise Coupling from Printed Circuit Board to Shielding Enclosure

The power distribution network in a printed circuit board (PCB) inside a compact-size enclosure is an effective path for high-speed digital noise to be coupled to the RF receivers inside the same enclosure, causing RF interference (RFI) issues. This noise coupling mechanism from PCB to shielding enclosure is investigated in this paper using the cavity model and the segmentation technique. In this approach, the structure of an enclosure with a PCB inside is divided into cavities with both horizontal and vertical connections. Modeling result agrees well with full wave simulations, and the simulation time is considerably reduced. Furthermore, the relationship among the noise coupling, the PCB-related resonances, and the enclosure-related resonances is studied as well

Closed-form Expressions for Determining Approximate PMC Boundaries Around an Aperture in a Metal Cavity Wall

Modern electronic systems may use mixed RF/digital technologies to achieve various functionalities, which leads to various intra-system interference problems including the RF interference from noisy digital circuits to sensitive RF receivers, especially when the overall system is contained in a metal enclosure. A fast method based on a cavity formulation can be used to estimate the internal noise coupling mechanisms inside the enclosure. This method assumes that only the TMz0 mode exists inside the enclosure, i.e., the electric field along the z-direction is constant. The cavity formulation fails in the region adjacent to an aperture in an enclosure wall, since the aperture introduces higher order modes. The developed closed-form expressions compute the Ez-field variation along the z-direction. Thus, they can be used to estimate the breakpoint where the cavity method is no longer effective

ENZYME ENGINEERING AT ALMAC: Case studies of enzyme discovery and engineering

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Leg 202 summary

More than 7 km of long and relatively continuous sediment sequences from 11 sites in the southeast and equatorial Pacific were recovered during Leg 202 for the study of the Earth’s climate and biogeochemical systems on scales that range from tectonic (millions of years) to orbital (tens to hundreds of thousands of years) and centennial to millennial (hundreds to thousands of years). These materials will be used to test a broad set of hypotheses on (1) the evolution of the South Pacific Ocean as it responds to and modulates the effects of major tectonic and climatic events, such as the opening of the Drake Passage, uplift of the Andes Mountains, closure of the Isthmus of Panama, and major expansion of polar ice sheets; (2) linkage between climate and biogeochemical changes in the high latitudes and the equatorial Pacific, related to rhythmic changes in Earth’s orbit, and the relationship of such changes to well-known glacial events of the Northern Hemisphere; and (3) global and regional changes in climate, biota, and ocean chemistry on timescales of centuries to millennia to millions of years. Three sites (1236, 1237, and 1241) targeted sequences with relatively low sedimentation rates of <30 m/m.y. to obtain long records of climate and oceanographic change representing the Neogene and, in some cases, the late Paleogene that are not subject to severe burial diagenesis. Two sites (1238 and 1239) targeted moderate sedimentation rates of 30– 80 m/m.y. to assess orbital-scale climate and biogeochemistry oscillations at a resolution suitable for the tuning of timescales and examination of changing responses to orbital forcing during the late Neogene. Six sites (1232 through 1235, 1240, and 1242) recovered sediments that accumulated rapidly, at rates of 80–2000 m/m.y., near the equator and in the higher southern latitudes to assess equator-to-pole climate and biogeochemical linkages at centennial, millennial, and orbital timescales. Drilling strategy and near real-time stratigraphic correlation played significant roles in the successful recovery of these sequences. Drilling multiple holes at each site and extensive use of overdrilling with the advanced piston corer (APC) provided long records with continuous recovery. Innovative use of rapid core logging allowed for real-time optimization of drilling strategies that maximized recovery and minimized redundant coring. Analysis of core expansion, as well as core-log integration and double extended core barrel (XCB) coring at some sites, facilitated the assembly of cores into a depth framework that will improve the quantitative analyses of sediment accumulation rates. On Nazca Ridge, Site 1237 provides a continuous sediment sequence, recovered in overlapping APC cores, that spans >30 m.y. (modern to middle Oligocene). Exceptional preservation of the flora and fauna in this long, continuous record indicates that this site will provide a much-needed stratigraphic reference in the southeast Pacific. Abrupt changes in the presence of volcanic ash layers here document an increase in tectonic activity during the late Miocene, while nearly at the same time an increase in dust flux and biogenic components associated with productive upwelling systems, such as diatoms, are associated with late Cenozoic cooling that may be associated with uplift of the Andes. Site 1236 provides an equally good record from shallower water depths for the last 28 m.y. that, when paired with Site 1237, will document variations of deep, intermediate, and surface water masses in the subtropical South Pacific. Near the equator, Sites 1238–1241 provide evidence for rhythmic oscillations of pelagic and hemipelagic sediments on the scale of Earth’s orbital cycles, which will help to test hypotheses on tropical vs. polar origins of the well-known 100-k.y. climate cycle that characterizes the late Pleistocene, as well as the response of the equatorial Pacific to closure of the Isthmus of Panama over millions of years. Again, complete recovery of long and well-preserved sediment sequences will provide unprecedented resolution of biotic and environmental changes. Century- to millennial-scale climate changes can be addressed with the records from rapidly accumulating (40–200 cm/k.y.) sediments recovered at Sites 1233–1235 from the central Chile margin. These sites will provide important data related to the southern westerlies and Antarctic Intermediate Water variability. A detailed record of paleomagnetic intensity and secular variability will link these records into a global chronological framework. At Site 1232, in the Chile Basin, a rapidly accumulating Pleistocene sequence documents terrigenous sediments eroded from the southern Andes and transported to the deep via turbidity currents. Near the equator, Sites 1240 and 1242 have moderately high sedimentation rates (~8–13 cm/k.y.), which will help to test linkages of millennial-scale climate changes between low and high latitudes. Together, the array of sites recovered during Leg 202 provides a new view of Southern Hemisphere and tropical climate variability and biogeochemical systems across a broad range of spatial and temporal scales in a region of the ocean that has received relatively little study in the past.Shipboard scientific party : Chapter 1, Leg 202 Summar

Increased dissolved terrestrial input to the coastal ocean during the last deglaciation

Here we present the first downcore results for a new paleoproxy, the Mn/Ca ratio of foraminiferal calcite, applied to sediment accumulated in the extreme Eastern Tropical North Pacific (ETNP) over the last 30,000 years. The Mn/Ca results are compared to oxygen isotopes and sea surface temperature calculated from Mg/Ca. We determined metal ratios using flow-through time-resolved analysis to minimize the effects of secondary mineralization. The foraminiferal species used for this study calcify at different depths. Core top ratios of these variant species change in proportion to the concentration of dissolved manganese in the water column at the depth of calcification. Since terrestrial input and oxidation reduction reactions control the levels of dissolved Mn in the oceans today, it therefore should be possible to use the Mn/Ca ratios of foraminifera as a proxy for these processes in the past. Mn/Ca of a mixed-layer species (G. ruber) suggest that dissolved terrestrial input to the surface waters of the ETNP during the last glacial maximum was lower than today but began to increase with initial sea level rise and reached a maximum at 15 ka B.P. before coming down to present-day levels at the end of sea level rise in the mid-Holocene (7–5 ka). Ratios of a deeper calcifying species (N. dutertrei) mimic those of G. ruber over this same time period, consistent with shoaling of the 18°C thermocline. Mn/Ca of a benthic species (U. peregrina) does not show a maximum at 15 ka, suggesting that Mn was efficiently remineralized in the water column during deglaciation. Assuming that the period from the last glacial until the mid-Holocene was a time of increased productivity, as elevated Mn might imply, the oxygen minimum zone (OMZ) was at least as well developed during deglaciation as it is today. Expansion of the OMZ may have contributed to the Mn/Ca trends we observe through time

Plasmas and Controlled Nuclear Fusion

Contains reports on three research projects.U. S. Atomic Energy Commission (Contract AT(30-1)-3980

Development and application of novel engineered transaminase panels assisted by in- silico rational design for the production of chiral amines

There is a high demand for the synthesis of chiral amines as building blocks for a large number of industrially valuable compounds. Transaminases (TAm) offer an enzymatic route for the synthesis of chiral amines that avoids complex chemical synthesis [1]. However, their catalytic efficiency towards bulky ketone substrates is greatly limited by steric hinderance [2]. This poster highlights a rational design strategy of combining in silico and in vitro methods to engineer the transaminase enzyme with a minimal number of mutations, achieving high catalytic activity and high enantioselectivity. The wildtype TAm showed no detectable activity towards the ketone 2-acetylbiphenyl but upon introduction of two mutations detectable enzyme activity was observed. The reaction rate was improved a further 1716-fold with the rationally designed variant, that contained a further 5 mutations, producing the corresponding enantiomeric pure (S)-amine (enantiomeric excess (ee) value of \u3e99%)[3]. In addition, screening of in silico designed (R)-TAm mutant panels in resolution mode offered an attractive and efficient route for the preparation of problematic (S)-amines. A mutant was identified from the panels that gave complete resolution of the racemic amine (high substrate loading) to leave the desired enantiomer at a low enzyme loading fit for process development towards an economically viable scale up process. [1] R. C. Simon, et al, ACS Catal. 2014, 4(1) [2] F. Steffen-Munsberg, et al, ChemCatChem 2013, 5, (1) [3]D.F.A.R.Dourado et al, ACS Catal. 2016, 6 (11