Photocatalytic activities of tin(IV) oxide surface-modified titanium(IV) dioxide show a strong sensitivity to the TiO 2 crystal form

Surface modification of rutile TiO2 with extremely small SnO2 clusters gives rise to a great increase in its UV light activity for degradation of model organic water pollutants, while the effect is much smaller for anatase TiO2. This crystal form sensitivity is rationalized in terms of the difference in the electronic modification of TiO2 through the interfacial Sn−O−Ti bonds. The increase in the density of states near the conduction band minimum of rutile by hybridization with the SnO2 cluster levels intensifies the light absorption, but this is not seen with modified anatase. The electronic transition from the valence band to the conduction band causes the bulk-to-surface interfacial electron transfer to enhance charge separation. Further, electrons relaxed to the conduction minimum are smoothly transferred to O2 due to the action of the SnO2 species as an electron transfer promoter.

Global distributions of diazotrophs abundance and biomass - Depth integrated values computed from a collection of source datasets - Contribution to the MAREDAT World Ocean Atlas of Plankton Functional Types

The MAREDAT atlas covers 11 types of plankton, ranging in size from bacteria to jellyfish. Together, these plankton groups determine the health and productivity of the global ocean and play a vital role in the global carbon cycle. Working within a uniform and consistent spatial and depth grid (map) of the global ocean, the researchers compiled thousands and tens of thousands of data points to identify regions of plankton abundance and scarcity as well as areas of data abundance and scarcity. At many of the grid points, the MAREDAT team accomplished the difficult conversion from abundance (numbers of organisms) to biomass (carbon mass of organisms). The MAREDAT atlas provides an unprecedented global data set for ecological and biochemical analysis and modeling as well as a clear mandate for compiling additional existing data and for focusing future data gathering efforts on key groups in key areas of the ocean. The present data set presents depth integrated values of diazotrophs abundance and biomass, computed from a collection of source data sets.

(Table 1) Stable isotope records of clathrite and water

Aragonitic clathrites are methane-derived precipitates that are found at sites of massive near-seafloor gas hydrate (clathrate) accumulations at the summit of southern Hydrate Ridge, Cascadia margin. These platy carbonate precipitates form inside or in proximity to gas hydrate, which in our study site currently coexists with a fluid that is highly enriched in dissolved ions as salts are excluded during gas hydrate formation. The clathrites record the preferential incorporation of 18O into the hydrate structure and hence the enrichment of 16O in the surrounding brine. We measured d18O values as high as 2.27 per mil relative to Peedee belemnite that correspond to a fluid composition of -1.18 per mil relative to standard mean ocean water. The same trend can be observed in Ca isotopes. Ongoing clathrite precipitation causes enrichment of the 44Ca in the fluid and hence in the carbonates. Carbon isotopes confirm a methane source for the carbonates. Our triple stable isotope approach that uses the three main components of carbonates (Ca, C, O) provides insight into multiple parameters influencing the isotopic composition of the pore water and hence the isotopic composition of the clathrites. This approach provides a tool to monitor the geochemical processes during clathrate and clathrite formation, thus recording the evolution of the geochemical environment of gas hydrate systems.

Summary of 40Ar/39Ar results from sediment core CRP-2A (Table 1)

40Ar/39Ar analyses of tephra and clasts of volcanic rock provide age constraints for upper parts of the CRP-2A core. Single-crystal laser-fusion analyses of anorthoclase phenocrysts from three tephra-bearing layers yielded the most precise age constraints for CRP-2A. The dated tephra layers are: 1) a 2.7-m-thick interval of pumice and ash layers between 111.5 and 114.2 meters below sea floor (mbsf) (weighted mean age = 21.44 ± 0.05 Ma, +2.2); 2) a concentration of pumice near 193.4 mbsf (23.98 ± 0.13 Ma): and 3) a concentration of pumice near 280 mbsf (24,22 ± 0.03 Ma) (all ages are calibrated relative to Fish Canyon Tuff sanidine at 27.84 Ma). The 111 to 114 mbsf tephra is almost entirely non-reworked, and the 193 mbsf and 280 mbsf tephra concentrations are interpreted as being reworked and redeposited soon after eruption. All three of the tephra ages are therefore considered to be equivalent to depositional ages. The variation in precision of these three age determinations is largely a function of phenocryst size and abundance. The accuracy of these ages is equal to the accuracy of the current calibration of the 40Ar/39Ar methode (about ± 1 %). 40Ar/39Ar results from volcanic clasts provide three additional maximum age constraints for the CRP-2A core. Single-crystal laser-fusion of sanidine phenocrysts from a rhyolitic clast from 294 mbsf yielded a precise maximum depositional age of 24.98 ± 0.08 Ma, and plateau ages of groundmass concentrates from basaltic clasts near 36.02 mbsf and 125.92 mbsf yielded maximum depositional ages of 19.18 ± 0.12 Ma, and 22.56 ± 0.14 Ma, respectively. The 40Ar/39Ar data, in association with biostratigraphic, paleomagnetic, and isotopic age constraints for CRP-2A, confirm interpretation for rapid sedimentation rates in the 36 to 280 mbsf interval, particularly in the 193 to 280 mbsf interval where they support interpretations for sedimentation cycles spanning 100 k.y. intervals. In addition to the 19 to 25 Ma ages measured from thephra layers and clasts, provenance-related ages ranging from 150 to 450 Ma were determined from clasts and individual detrital or xenocrystic crystals from CRP-2A.

Understanding arsenic mobility and speciation in lake sediments impacted by ore roasting near Giant mine, NWT

The roasting of gold-bearing arsenopyrite at Giant mine (Northwest Territories) between 1949 and 1999 released approximately 20,000 tonnes of toxic arsenic-bearing aerosols in the local aerial environment. Detailed examination of lake sediments, sediment porewaters, surface waters and lake hydrology sampled from three lakes of differing limnological characteristics was conducted in summer and winter conditions. Samples were analyzed for solid and dissolved elemental concentrations, speciation and mineralogy. The three lakes are located less than 5km from the mine roaster, and downwind, based on predominant wind direction. The objective of the study was to assess the controls on the mobility and fate of arsenic in these roaster-impacted subarctic lacustrine environments. Results show that the occurrence of arsenic trioxide in lake sediments coincides with the regional onset of industrial activities. The bulk of arsenic in sediments is contained in the form of secondary sulphide precipitates, with iron oxides hosting a minimal amount of arsenic near the surface-water interface. The presence of geogenic arsenic is likely contained as dilute impurities in common rock-forming minerals, and is not believed to be a significant source of arsenic to sediments, porewaters or lake waters. Furthermore, the well correlated depth-profiles of arsenic, antimony and gold in sediments may help reveal roaster impact. The soluble arsenic trioxide particles contained in sediments act as the primary source of arsenic into porewaters. Dissolved arsenic in reducing porewaters both precipitate as secondary sulphides in situ, and diffuse upwards into the overlying lake waters. Arsenic diffusion out of porewaters, combined with watercourse-driven residence time, are estimated to be the predominant mechanisms controlling arsenic concentrations in overlying lake waters. The sequestration of arsenic from porewaters as sulphide precipitates, in the study lakes, is not an effective process in keeping lake-water arsenic concentrations below guidelines for the protection of the freshwater environment and drinking water. Seasonal impacts on lake geochemistry derive from ice covering lake waters, cutting them off from of atmospheric oxygen, along with the exclusion of solutes from the ice. Such effects are limited in deep lakes but are can be an important factor controlling arsenic precipitation and mobility in ponds.

Pulling Back the Veil: The Characterization and Habitability of Enshrouded Worlds

Thesis (Ph.D.)--University of Washington, 2016-08

The (Im)possibility of the Intellectual Worker Inside the Neoliberal University

The provocation and point of this paper is that universities of the North during the era of neoliberalism of have been sucked of their human life-giving capacities. What remains are closed doors and bare walls. Lest we give the impression of a hopelessly romantic view of the university (and embark upon a lament for some paradise lost), let us be clear from the outset: there is no such place – and there never has been. As will be outlined below, a consideration of the history of the university reveals it was born and has persistently drawn its life breath from oxygen formed in the tension ridden mix of an impulse to human freedom and accommodation to powers of church, state and capital. But, we contend, history is now the witness to the almost complete dissolution of that tension: to the exhaustion of emancipatory impulses in the service of indoctrination, regulation and accumulation. In the church-state-capital triad, it is the latter that has emerged hegemonic. Importantly, we argue, its dominance has emerged with the rise of what Paul Baran and Paul Sweezy describe as monopoly capital: the move from competitive (small entrepreneurial business) forms to monopolistic (large corporate business) regimes of accumulation (Baran & Sweezy 1966). A central feature of monopoly capitalism is its need for significant financial support of national states and the harnessing of public resources such as universities to feed accumulation. It is no surprise that neoliberalism, despite its neoclassical economic pronouncements, is a ‘big state’ advocate (Harvey 2005). Our argument is that neoliberalism, as the political workhorse of monopoly capitalism, has overseen a makeover of universities so they might behave like a monopoly capitalist corporation. Our time is the time of the near global domination of capital. The university has succumbed. In its colonisation – its capitalisation – the university has not only reinvented itself as a willing ally of capital but has also set about remaking itself in its image.

Ecology and physical condition of red deer in the Iberian Peninsula: implications for management

The red deer (Cervus elaphus) is currently one of the most widespread and abundant wild ungulates in the Iberian Peninsula and is extremely important both ecologically, as a key species for the functioning of the ecosystems, and economically, as a major game species. In Iberia, red deer populations are subjected to different management systems that may affect the physical condition of the individuals, with further consequences for population dynamics. Studies investigating the effects of management practices and environmental conditions on the performance of red deer are still rare regarding Mediterranean ecosystems. Much of the knowledge concerning the ecology of red deer and the impact of management on its physical condition is based on studies conducted in northern and central regions of Europe, where climatological features and management practices differ from those observed in the Mediterranean areas of Iberia. Studies on a biogeographical scale can provide important insights into the relationships between species and a particular environment and contribute to the development of more targeted and appropriate management practices. The optimisation of sampling procedures and the fine-tuning of pre-existing analytical techniques are also fundamental to a more cost-effective monitoring and, therefore, are of enormous value to wildlife managers. In this context, the main aims of this thesis were: 1) to optimise the procedures used to assess the physical condition of red deer; and 2) to identify relevant management and environmental factors affecting the nutritional condition and stress physiology of red deer in the Mediterranean ecosystems of Iberia, as well as any potential interactions between those factors. Two studies with a methodological focus, presented in the first part of the thesis, demonstrated that the physical condition of red deer can be evaluated more simply, using more cost- and time-effective procedures than those traditionally used: i) it was shown that only one kidney and its associated fat is enough to assess nutritional condition in red deer; and ii) the feasibility of using near infrared spectroscopy to predict the concentrations of stress hormone metabolites was demonstrated using faeces of red deer for the first time. Subsequently, two large-scale observational studies, conducted in representative red deer populations found in Mediterranean Iberia, highlighted the importance of considering seasonal environmental variations and variables related to hunting management practices to better understand the nutritional and physiological ecology of red deer. High population densities had adverse effects on the nutritional condition of the deer and were associated with increased stress levels in natural populations without supplementary feeding. Massive hunting events involving the use of hounds were also identified as a potential source of chronic stress in red deer. The research presented in this thesis has clear implications regarding the management and monitoring of red deer populations in Mediterranean environments and is intended to help wildlife managers to implement more effective monitoring programmes and sustainable management practices.

Ecological health analysis of Caspian marine environment based on the diversity and distribution pattern of meiofauna in the Mazandaran Province, Caspian Sea

Biodiversity and distribution of benthic meiofauna in the sediments of the Southern Caspian Sea (Mazandaran) was studied in order to introducing and determining of their relationship with the environmental factors. From 12 stations (ranging in depths 5, 10, 20 and 50 meters), sediment samples were gathered in 6 months (2012). Environmental factors of water near the bottom including temperature, salinity, dissolved oxygen and pH were measured during sampling with CTD and grain size and total organic matter percentage and calcium carbonate were measured in laboratory. In different months, the average water temperature (9.52-23.93), dissolved oxygen (7.71-10.53 mg/L), salinity (10.57±0/07 and 10.75±0/04 ppt), pH (7.44±0/29 and 7.41±0/22), EC (17.97±0/12 and 18.30±0/04μs/cm2), TDS (8.92±0/04 and 9.14±0/02 mg/L), total organic matter (5.83±1/43 and 6.25±0/97%) and calcium carbonate (2.36±0/36 and 1.68±0/19%) were measured respectively. Structure of the sediment samples mostly consisted of fine sand; very fine sand, silt and clay. From the 4 group animals (Foraminifera, Crustacea, Worms and Mollusca), there were identified 40species belong to 29 genera of 25 families. The cosmopolitan foraminifer, Ammonia beccarii caspica, was common in all sampling stations. Result showed that depth was important factor on distribution of meiofauna. Most density of foraminifera and crustacean was observed in depth of 20m and for mollusca and worms observed in 5m. Shannon diversity index decreased with depth that showed in shallow water diversity was higher than deep water. Mean of maximum and minimum Shannon index was obsorvers in depth of 5m and 50 m that was measured in order 0.93 and 0.43. Account of Shannon index showed that this area is under pressure. Account of peioleo index showed distribution in this area was not steady.

Aerodynamic behavior of an airfoil with morphing trailing edge for wind turbine applications

The length of wind turbine rotor blades has been increased during the last decades. Higher stresses arise especially at the blade root because of the longer lever arm. One way to reduce unsteady blade-root stresses caused by turbulence, gusts, or wind shear is to actively control the lift in the blade tip region. One promising method involves airfoils with morphing trailing edges to control the lift and consequently the loads acting on the blade. In the present study, the steady and unsteady behavior of an airfoil with a morphing trailing edge is investigated. Two-dimensional Reynolds-Averaged Navier-Stokes (RANS) simulations are performed for a typical thin wind turbine airfoil with a morphing trailing edge. Steady-state simulations are used to design optimal geometry, size, and deflection angles of the morphing trailing edge. The resulting steady aerodynamic coefficients are then analyzed at different angles of attack in order to determine the effectiveness of the morphing trailing edge. In order to investigate the unsteady aerodynamic behavior of the optimal morphing trailing edge, time-resolved RANS-simulations are performed using a deformable grid. In order to analyze the phase shift between the variable trailing edge deflection and the dynamic lift coefficient, the trailing edge is deflected at four different reduced frequencies for each different angle of attack. As expected, a phase shift between the deflection and the lift occurs. While deflecting the trailing edge at angles of attack near stall, additionally an overshoot above and beyond the steady lift coefficient is observed and evaluated.

Investigating the cosmic-ray ionization rate in the galactic interstellar medium through observations of H3+

Observations of H3+ in the Galactic diffuse interstellar medium (ISM) have led to various surprising results, including the conclusion that the cosmic-ray ionization rate (zeta_2) is about 1 order of magnitude larger than previously thought. The present survey expands the sample of diffuse cloud sight lines with H3+ observations to 50, with detections in 21 of those. Ionization rates inferred from these detections are in the range (1.7+-1.0)x10^-16 s^-1 < zeta_2 < (10.6+-6.8)x10^-16 s^-1 with a mean value of zeta_2=(3.3+-0.4)x10^-16 s^-1. Upper limits (3sigma) derived from non-detections of H3+ are as low as zeta_2 < 0.4x10^-16 s^-1. These low upper-limits, in combination with the wide range of inferred cosmic-ray ionization rates, indicate variations in zeta_2 between different diffuse cloud sight lines. Calculations of the cosmic-ray ionization rate from theoretical cosmic-ray spectra require a large flux of low-energy (MeV) particles to reproduce values inferred from observations. Given the relatively short range of low-energy cosmic rays --- those most efficient at ionization --- the proximity of a cloud to a site of particle acceleration may set its ionization rate. Variations in zeta_2 are thus likely due to variations in the cosmic-ray spectrum at low energies resulting from the effects of particle propagation. To test this theory, H3+ was observed in sight lines passing through diffuse molecular clouds known to be interacting with the supernova remnant IC 443, a probable site of particle acceleration. Where H3+ is detected, ionization rates of zeta_2=(20+-10)x10^-16 s^-1 are inferred, higher than for any other diffuse cloud. These results support both the concept that supernova remnants act as particle accelerators, and the hypothesis that propagation effects are responsible for causing spatial variations in the cosmic-ray spectrum and ionization rate. Future observations of H3+ near other supernova remnants and in sight lines where complementary ionization tracers (OH+, H2O+, H3O+) have been observed will further our understanding of the subject.

A deformation model of flexible, high area-to-mass ratio debris under perturbations and validation method

A new type of space debris was recently discovered by Schildknecht in near -geosynchronous orbit (GEO). These objects were later identified as exhibiting properties associated with High Area-to-Mass ratio (HAMR) objects. According to their brightness magnitudes (light curve), high rotation rates and composition properties (albedo, amount of specular and diffuse reflection, colour, etc), it is thought that these objects are multilayer insulation (MLI). Observations have shown that this debris type is very sensitive to environmental disturbances, particularly solar radiation pressure, due to the fact that their shapes are easily deformed leading to changes in the Area-to-Mass ratio (AMR) over time. This thesis proposes a simple effective flexible model of the thin, deformable membrane with two different methods. Firstly, this debris is modelled with Finite Element Analysis (FEA) by using Bernoulli-Euler theory called “Bernoulli model”. The Bernoulli model is constructed with beam elements consisting 2 nodes and each node has six degrees of freedom (DoF). The mass of membrane is distributed in beam elements. Secondly, the debris based on multibody dynamics theory call “Multibody model” is modelled as a series of lump masses, connected through flexible joints, representing the flexibility of the membrane itself. The mass of the membrane, albeit low, is taken into account with lump masses in the joints. The dynamic equations for the masses, including the constraints defined by the connecting rigid rod, are derived using fundamental Newtonian mechanics. The physical properties of both flexible models required by the models (membrane density, reflectivity, composition, etc.), are assumed to be those of multilayer insulation. Both flexible membrane models are then propagated together with classical orbital and attitude equations of motion near GEO region to predict the orbital evolution under the perturbations of solar radiation pressure, Earth’s gravity field, luni-solar gravitational fields and self-shadowing effect. These results are then compared to two rigid body models (cannonball and flat rigid plate). In this investigation, when comparing with a rigid model, the evolutions of orbital elements of the flexible models indicate the difference of inclination and secular eccentricity evolutions, rapid irregular attitude motion and unstable cross-section area due to a deformation over time. Then, the Monte Carlo simulations by varying initial attitude dynamics and deformed angle are investigated and compared with rigid models over 100 days. As the results of the simulations, the different initial conditions provide unique orbital motions, which is significantly different in term of orbital motions of both rigid models. Furthermore, this thesis presents a methodology to determine the material dynamic properties of thin membranes and validates the deformation of the multibody model with real MLI materials. Experiments are performed in a high vacuum chamber (10-4 mbar) replicating space environment. A thin membrane is hinged at one end but free at the other. The free motion experiment, the first experiment, is a free vibration test to determine the damping coefficient and natural frequency of the thin membrane. In this test, the membrane is allowed to fall freely in the chamber with the motion tracked and captured through high velocity video frames. A Kalman filter technique is implemented in the tracking algorithm to reduce noise and increase the tracking accuracy of the oscillating motion. The forced motion experiment, the last test, is performed to determine the deformation characteristics of the object. A high power spotlight (500-2000W) is used to illuminate the MLI and the displacements are measured by means of a high resolution laser sensor. Finite Element Analysis (FEA) and multibody dynamics of the experimental setups are used for the validation of the flexible model by comparing with the experimental results of displacements and natural frequencies.

Costa del Sol (Spain), analysis of economic and land changes caused by tourism

Malaga is in southern Spain, in a region called Andalusia. Costa del Sol belongs to the province of Malaga, near the Strait of Gibraltar and near the coast of Africa (about 300 km) and about 2,300 km of Sluptz. The Costa del Sol is next to the Mediterranean Sea and near the Atlantic Ocean. Strong and rapid growth of tourism in the countries of southern Europe and in Poland. Spain currently (2015) is the third largest inbound of international tourism (68 mil.) and the second inbound in tourism revenue. Europe is a major world tourist region. The first recipient of tourism in the world is France. Most tourism takes place between developed countries.

Investigating the Role of O-GlcNAc Glycosylation in Neurodegeneration

O-GlcNAc glycosylation of nuclear and cytosolic proteins is an essential post-translational modification implicated in many diseases, from cancer to diabetes. Importantly, many important neuronal proteins are also O-GlcNAc modified, and aberrant O-GlcNAcylation of these proteins may contribute to the pathology of neurodegenerative diseases although these mechanisms have not been well defined. Here we investigated the role of O-GlcNAc glycosylation in the brain, utilizing both chemistry and molecular biology to study O-GlcNAc transferase (OGT), the enzyme that adds the sugar modification. To evaluate the role of OGT in adult neurons, we generated a forebrain-specific conditional knockout of OGT (OGT cKO) in mice. Although indistinguishable from wild-type littermates at birth, after three weeks we observe progressive neurodegeneration in OGT cKO mice. Hallmarks of Alzheimer’s disease, including neuronal loss, neuroinflammation, behavioral deficits, hyperphosphorylated tau, and amyloid beta peptide accumulation, are observed. Furthermore, decreases in OGT protein levels were found in human AD brain tissue, suggesting that altered O-GlcNAcylation likely contributes to neurodegenerative diseases in humans. This model is one of a few mouse models that recapitulate AD phenotypes without mutating and overexpressing human tau, amyloid precursor protein, or presenilin, highlighting the essential role of OGT in neurodegenerative pathways.

Given the importance of OGT in the brain, we further investigated the regulation of the OGT enzyme by phosphorylation. We found that phosphorylation of OGT near its C-terminus reduces its activity in cancer cells, and have developed phosphorylation-specific antibodies to aid mechanistic studies. Furthermore, mutation of this phosphorylation site on OGT, followed by overexpression in neurons was shown to enhance neurite outgrowth, demonstrating a functional consequence for this site. Thus phosphorylation of OGT inhibits its activity and enhances neurite outgrowth, and current studies aim to characterize the signaling pathway that regulates OGT phosphorylation in neurons.

Probabilistic Imaging and Dynamic Modeling of Earthquake Source Processes

Investigation of large, destructive earthquakes is challenged by their infrequent occurrence and the remote nature of geophysical observations. This thesis sheds light on the source processes of large earthquakes from two perspectives: robust and quantitative observational constraints through Bayesian inference for earthquake source models, and physical insights on the interconnections of seismic and aseismic fault behavior from elastodynamic modeling of earthquake ruptures and aseismic processes.

To constrain the shallow deformation during megathrust events, we develop semi-analytical and numerical Bayesian approaches to explore the maximum resolution of the tsunami data, with a focus on incorporating the uncertainty in the forward modeling. These methodologies are then applied to invert for the coseismic seafloor displacement field in the 2011 Mw 9.0 Tohoku-Oki earthquake using near-field tsunami waveforms and for the coseismic fault slip models in the 2010 Mw 8.8 Maule earthquake with complementary tsunami and geodetic observations. From posterior estimates of model parameters and their uncertainties, we are able to quantitatively constrain the near-trench profiles of seafloor displacement and fault slip. Similar characteristic patterns emerge during both events, featuring the peak of uplift near the edge of the accretionary wedge with a decay toward the trench axis, with implications for fault failure and tsunamigenic mechanisms of megathrust earthquakes.

To understand the behavior of earthquakes at the base of the seismogenic zone on continental strike-slip faults, we simulate the interactions of dynamic earthquake rupture, aseismic slip, and heterogeneity in rate-and-state fault models coupled with shear heating. Our study explains the long-standing enigma of seismic quiescence on major fault segments known to have hosted large earthquakes by deeper penetration of large earthquakes below the seismogenic zone, where mature faults have well-localized creeping extensions. This conclusion is supported by the simulated relationship between seismicity and large earthquakes as well as by observations from recent large events. We also use the modeling to connect the geodetic observables of fault locking with the behavior of seismicity in numerical models, investigating how a combination of interseismic geodetic and seismological estimates could constrain the locked-creeping transition of faults and potentially their co- and post-seismic behavior.