591 research outputs found
Site U1334
Integrated Ocean Drilling Program (IODP) Site U1334 (7°59.998?N, 131°58.408?W; 4799 meters below sea level [mbsl]) (Fig. F1; Table T1) is located ~380 km southeast of previously drilled Ocean Drilling Program (ODP) Site 1218 (~42 Ma crust) in the central area drilled during the Pacific Equatorial Age Transect (PEAT) program (IODP Expedition 320/321). Site U1334 (~38 Ma crust) is situated ~100 km north of the Clipperton Fracture Zone on abyssal hill topography draped with ~280 m sediment (Fig. F2). The fabric of the abyssal hills within the sites is oriented either due north or slightly east of due north.Water depth in the vicinity of Site U1334 ranges between 5.0 and 5.1 km for the depressions between the abyssal hills. The abyssal hills range between 4.70 and 4.85 km water depth and generally show a thicker and more consistent sediment cover than the basins. In fact, a significant amount of the bathymetric difference between hills and basins is controlled by the amount of sediment cover. The comparison of sediment thickness and clarity of seismic sections led us to select a location on the middle elevation of one of the abyssal plateaus.Site U1334 sediments were estimated to have been deposited on top of late middle Eocene crust with an age of ~38 Ma and target the events bracketing the EoceneâOligocene transition with the specific aim of recovering carbonate-bearing sediments of latest Eocene age prior to a large deepening of the calcium carbonate compensation depth (CCD) that occurred during this greenhouse to icehouse transition (Kennett and Shackleton, 1976; Miller et al., 1991; Zachos et al., 1996; Coxall et al., 2005). The EoceneâOligocene transition experienced the most dramatic deepening of the Pacific CCD during the Paleogene (van Andel, 1975), which has now been shown by Coxall et al. (2005) to coincide with a rapid stepwise increase in benthic oxygen stable isotope ratios, interpreted to reflect a combination of growth of the Antarctic ice sheet and decrease in deepwater temperatures (DeConto et al., 2008; Liu et al., 2009).<br/
Session B, 2017 First Place: A Comparison of Macroinvertebrate Assemblages Found in Forest Fungi of Different Hymenial Types
Insects and fungi are known to play important roles in overall forest health; however, the relationship between the two is not well studied. In the field we observed insects in gilled mushrooms. This led us to question if other fungal fruiting bodies also contained macroinvertebrate assemblages. We hypothesized that there would be a significant difference of macroinvertebrate assemblages between the three hymenial types studied: gilled, pored, and tubed. We also hypothesized that older fungi would contain larger assemblages of macroinvertebrates. Fungi were collected from five different areas at Cranberry Lake Biological Station. Macroinvertebrates were extracted using Berlese funnels for 4.5-5 hours. The fungi represent both experimental and sampling units (n=32), which are independent of the macroinvertebrate assemblages. ANOVA and Tukey tests were used to analyze data and results will be presented and discussed. Both larval and adult forms were found within the fruiting bodies, where the fungi appear to be serving as a food source and reproductive site for numerous macroinvertebrates
Physical Drivers of Phytoplankton Bloom Initiation in the Southern Ocean's Scotia Sea
Abstract:
The Scotia Sea is the site of one of the largest spring phytoplankton blooms in the Southern Ocean. Past studies suggest that shelfâiron inputs are responsible for the high productivity in this region, but the physical mechanisms that initiate and sustain the bloom are not well understood. Analysis of profiling float data from 2002 to 2017 shows that the Scotia Sea has an unusually shallow mixedâlayer depth during the transition from winter to spring, allowing the region to support a bloom earlier in the season than elsewhere in the Antarctic Circumpolar Current. We compare these results to the mixedâlayer depth in the 1/6° dataâassimilating Southern Ocean State Estimate and then use the model output to assess the physical balances governing mixedâlayer variability in the region. Results indicate the importance of lateral advection of Weddell Sea surface waters in setting the stratification. A Lagrangian particle release experiment run backward in time suggests that Weddell outflow constitutes 10% of the waters in the upper 200 m of the water column in the bloom region. This dense Weddell water subducts below the surface waters in the Scotia Sea, establishing a sharp subsurface density contrast that cannot be overcome by wintertime convection. Profiling float trajectories are consistent with the formation of Taylor columns over the region's complex bathymetry, which may also contribute to the unique stratification. Furthermore, biogeochemical measurements from 2016 and 2017 bloom events suggest that vertical exchange associated with this Taylor column enhances productivity by delivering nutrients to the euphotic zone
Oriented Internal Electrostatic Fields Cooperatively Promote Ground- and Excited-State Reactivity: A Case Study in Photochemical CO2 Capture
Oriented electrostatic fields can exert catalytic effects upon both the kinetics and the thermodynamics of chemical reactions; however, the vast majority of studies thus far have focused upon ground-state chemistry and rarely consider any more than a single class of reaction. In the present study, we first use density functional theory (DFT) calculations to clarify the mechanism of CO2 storage via photochemical carboxylation of o-alkylphenyl ketones, originally proposed by Murakami et al. (J. Am. Chem. Soc.2015, 137, 14063); we then demonstrate that oriented internal electrostatic fields arising from remote charged functional groups (CFGs) can selectively and cooperatively promote both ground- and excited-state chemical reactivity at all points along the revised mechanism, in a manner otherwise difficult to access via classical substituent effects. What is particularly striking is that electrostatic field effects upon key photochemical transitions are predictably enhanced in increasingly polar solvents, thus overcoming a central limitation of the electrostatic catalysis paradigm. We explain these observations, which should be readily extendable to the ground state.We acknowledge financial support from the Australian
Research Council (ARC) Centre of Excellence for Electromaterials Science (CE140100012, FL170100041), an ARC
Laureate Fellowship (to M.L.C.), and generous supercomputing time from the National Computational Infrastructure.
M.T.B. acknowledges an Australian Government Research
Training Program Scholarship and Deanâs Merit Scholarship in
Science. We also wish to thank Vincent Doan for helpful
discussions
Contribution of STAT3 and RAD23B in Primary SĂ©zary Cells to Histone Deacetylase Inhibitor FK228 Resistance
Business exit and strategic change: Sticking to the knitting or striking a new strategic path?
The purpose of this study is to examine the potential of business exit for initiating strategic change in divesting parent firms. In contrast to prior literature that mainly investigates the impact of different antecedents on the likelihood of business exit in general, this study additionally tests the influence of these antecedents on the choice between two exit types with a cross-industry sample of divesting firms listed in the German CDAX over the time period 1999-2004. A divestiture involving strategic change is a strategic business exit; otherwise it is denoted as status quo-preserving. The findings reveal that a relatively highly dissipated focus does not automatically enhance the likelihood of business exit in general and status quo-preserving business exit in particular. CEO turnover and pressures exerted by institutional investors predict neither strategic nor status quo-preserving business exit. Low firm performance does not nurture the likelihood of business exit per se but especially promotes status quo-preserving business exit
Wireless Communication Networks for Gas Turbine Engine Testing
A new trend in the field of Aeronautical Engine Health Monitoring is the implementation of wireless sensor networks (WSNs) for data acquisition and condition monitoring to partially replace heavy and complex wiring harnesses, which limit the versatility of the monitoring process as well as creating practical deployment issues. Using wireless technologies instead of fixed wiring will fuel opportunities for reduced cabling, faster sensor and network deployment, increased data acquisition flexibility and reduced cable maintenance costs. However, embedding wireless technology into an aero engine (even in the ground testing application considered here) presents some very significant challenges, e.g. a harsh environment with a complex RF transmission environment, high sensor density and high data-rate. In this paper we discuss the results of the Wireless Data Acquisition in Gas Turbine Engine Testing (WIDAGATE) project, which aimed to design and simulate such a network to estimate network performance and de-risk the wireless techniques before the deployment
BurstCube: A CubeSat for gravitational wave counterparts
BurstCube aims to expand sky coverage in order to detect, localize, and rapidly disseminate information about gamma-ray bursts (GRBs). BurstCube is a\u276U\u27 CubeSat with an instrument comprised of 4 Cesium Iodide (CsI) scintillators coupled to arrays of Silicon photo-multipliers (SiPMs) and will be sensitive to gamma-rays between 50 keV and 1 MeV. BurstCube will assist current observatories, such as Swift and Fermi, in the detection of GRBs as well as provide astronomical context to gravitational wave (GW) events detected by LIGO, Virgo, and KAGRA. BurstCube is currently in its development phase with a launch readiness date in early 2022
Evidence for genetic variance in resistance to tuberculosis in Great Britain and Irish Holstein-Friesian populations
peer-reviewedBackground: Here, we jointly summarise scientific evidence for genetic variation in resistance to infection with Mycobacterium bovis, the primary agent of bovine tuberculosis (TB), provided by two recent and separate studies of Holstein-Friesian dairy cow populations in Great Britain (GB) and Ireland. Methods: The studies quantified genetic variation within archived data from field and abattoir surveillance control programmes within each country. These data included results from the single intradermal comparative tuberculin test (SICTT), abattoir inspection for TB lesions and laboratory confirmation of disease status. Threshold animal models were used to estimate variance components for responsiveness to the SICTT and abattoir confirmed M. bovis infection. The link functions between the observed 0/1 scale and the liability scale were the complementary log-log in the GB, and logit link function in the Irish population. Results and discussion: The estimated heritability of susceptibility to TB, as judged by responsiveness to the SICTT, was 0.16 (0.012) and 0.14 (0.025) in the GB and Irish populations, respectively. For abattoir or laboratory confirmation of infection, estimates were 0.18 (0.044) and 0.18 (0.041) from the GB and the Irish populations, respectively. Conclusions: Estimates were all significantly different from zero and indicate that exploitable variation exists among GB and Irish Holstein Friesian dairy cows for resistance to TB. Epidemiological analysis suggests that factors such as variation in exposure or imperfect sensitivity and specificity would have resulted in underestimation of the true values
Measurement of the proton form factor by studying
Using data samples collected with the BESIII detector at the BEPCII collider,
we measure the Born cross section of at 12
center-of-mass energies from 2232.4 to 3671.0 MeV. The corresponding effective
electromagnetic form factor of the proton is deduced under the assumption that
the electric and magnetic form factors are equal . In
addition, the ratio of electric to magnetic form factors, , and
are extracted by fitting the polar angle distribution of the proton
for the data samples with larger statistics, namely at 2232.4 and
2400.0 MeV and a combined sample at = 3050.0, 3060.0 and 3080.0 MeV,
respectively. The measured cross sections are in agreement with recent results
from BaBar, improving the overall uncertainty by about 30\%. The
ratios are close to unity and consistent with BaBar results in
the same region, which indicates the data are consistent with the
assumption that within uncertainties.Comment: 13 pages, 24 figure
- âŠ