Physical Sciences and Mathematics Commons^™

Workshop | Body Worn Video Recorders: The Socio-Technical Implications Of Gathering Direct Evidence, Katina Michael, Alexander Hayes

Alexander Hayes Mr.

- From in-car video recording to body-worn video recording

- Exploring available technologies: how do they work, pros and cons

- Storing direct evidence in secure storage: factors to consider

- Citizens “shooting” back with POV tech – what are their rights?

- Crowdsourced sousveillance- harnessing public data for forensic profiling

- Police force policies and practices on the application of new media

Targeted Maximum Likelihood Estimation Of Natural Direct Effect, Wenjing Zheng, Mark Van Der Laan

Wenjing Zheng

In many causal inference problems, one is interested in the direct causal effect of an exposure on an outcome of interest that is not mediated by certain intermediate variables. Robins and Greenland (1992) and Pearl (2000) formalized the definition of two types of direct effects (natural and controlled) under the counterfactual framework. Since then, identifiability conditions for these effects have been studied extensively. By contrast, considerably fewer efforts have been invested in the estimation problem of the natural direct effect. In this article, we propose a semiparametric efficient, multiply robust estimator for the natural direct effect of a binary treatment …

Prescribed Fire Effects On Resource Selection By Cattle In Mesic Sagebrush Steppe. Part 1: Spring Grazing, Patrick Clark, Jaechoul Lee, Kyungduk Ko, Ryan Nielson, Douglas Johnson, David Ganskopp, Joe Chigbrow, Frederick Pierson, Stuart Hardegree

Kyungduk Ko

Prescribed fire is commonly applied world-wide as a tool for enhancing habitats and altering resource-selection patterns of grazing animals. A scientific basis for this practice has been established in some ecosystems but its efficacy has not been rigorously evaluated on mesic sagebrush steppe. Beginning in 2003, resource-selection patterns of beef cows were investigated using global positioning system (GPS) collars for 2 years before and for 5 years after a fall prescribed burn was applied to mesic sagebrush steppe in the Owyhee Mountains of southwestern Idaho, USA. Resource-selection functions (RSF) developed from these data indicated cattle selected for lightly to moderately …

Disk-Outflow Models As Applied To High Mass Star Forming Regions Through Methanol And Water Maser Observations, Hontas Farmer

Hontas F Farmer

As the recent publication by Breen et al (2013) found Class II methanol masers are exclusively associated with high mass star forming regions. Based on the positions of the Class I and II methanol and H2O masers, UC H II regions and 4.5 μm infrared sources, and the center velocities (vLSR) of the Class I methanol and H2O masers, compared to the vLSR of the Class II methanol masers, we propose three disk-outflow models that may be traced by methanol masers. In all three models, we have located the Class II methanol maser near the protostar, and the Class I …

Diatom Community Response To Climate Variability Over The Past 37,000 Years In The Sub-Tropics Of The Southern Hemisphere, Sarah Hembrow, Kathryn Taffs, Pia Atahan, Jeffrey Parr, Atun Zawadzki, Henk Heijnis

Jeffrey Parr

Climate change is impacting global surface water resources, increasing the need for a deeper understanding of the interaction between climate and biological diversity. This is particularly the case in the Southern Hemisphere sub-tropics, where little information exists on the aquatic biota response to climate variations. Palaeolimnological techniques, in particular the use of diatoms, are well established and can significantly contribute to the understanding of climatic variability and the impacts that change in climate have on aquatic ecosystems. A sediment core from Lake McKenzie, Fraser Island (Australia), was used to investigate interactions between climate influences and aquatic ecosystems. This study utilises …

Occluded C In Rice Phytoliths: Implications To Biogeochemical Carbon Sequestration, Zimin Li, Zhaoliang Song, Jeffrey Parr, Hailong Wang

Jeffrey Parr

Aims: Carbon (C) bio-sequestration within the phytoliths of plants, a mechanism of long-term biogeochemical C sequestration, may play a major role in the global C cycle and climate change. In this study, we explored the potential of C bio-sequestration within phytoliths produced in cultivated rice (Oryza sativa), a well known silicon accumulator.

Methods: The rice phytolith extraction was undertaken with microwave digestion procedures and the determination of occluded C in phytoliths was based on dissolution methods of phytolith-Si.

Results: Chemical analysis indicates that the phytolith-occluded C (PhytOC) contents of the different organs (leaf, stem, sheath and grains) on …

Synthesis Of Novel Sugar Diamino Acids, M Thillakan, A Katsifis, D Skropeta

Danielle Skropeta

Sugar amino acids (SAAs) are found in nature as good construction elements for the preparation of peptide mimetics and oiigosaccharides in drug design and development. The synthesis of SAAs is readily accomplished in few steps and more than 40 SAAs have been synthesised to date.2 Sugar amino acids with an additional amino group, the sugar diamino acid (SDAs) would represent a useful expansion to the library of SAAs available because one of the amino group and carboxylic acid is available for peptide coupling and the another amino/azide group allow to do further derivatisation via peptide or click chemistry such as …

Exploring Marine Resources For New Pharmaceutical Applications, Danielle Skropeta

Danielle Skropeta

No abstract provided.

Wicked Tools: The Value Of Scientific Models For Solving Maine’S Wicked Problems, Tim Waring

Timothy M Waring

“Wicked problems” are urgent, high-stake socioeconomic-environmental challenges that often involve ideological conflict and have no “best solutions.” Using examples from Maine’s Sustainability Solutions Initiative projects, Tim Waring describes how scientific models can be used to address these kinds of problems. When well-constructed and tested models are used to address policy-relevant issues, include input from stakeholders, and integrate social, economic and environmental dynamics, they can become “wicked tools” to address some of society’s biggest challenges.

Crosslinked Polymer Sheaths For Dispersing Individual Single-Walled Carbon Nanotubes In Nonaqueous Solvents, L. Ojha, M. Tchoul, K. Bastola, K. Ausman

Kevin D. Ausman

Single-walled carbon nanotubes have been suspended individually in water by encasing them in a thin, uniform layer of the crosslinkable polymer poly (N-vinylpyrrolidone-co-allylamine). When this polymer is crosslinked under dilute conditions, the polymer sheath, formerly stabilized by the hydrophobic effect, becomes stable to changes in the solvent system.

Fibonacci And Lucas Identities Via Graphs, Joe Demaio, John Jacobson

Joe DeMaio

Big History: The Sun: Season 1 Episode 13, Mojgan Behmand

Mojgan Behmand

Simultaneous Redox Conversion Of Chromium(Vi) And Arsenic(Iii) Under Acidic Conditions, Zhaohui Wang, Richard Bush, Leigh Sullivan, Jianshe Liu

Dr Zhaohui Wang

Arsenic and chromium are often abundant constituents of acid mine drainage (AMD) and are most harmful as arsenite (As(III)) and hexavalent (Cr(VI)). To simultaneously change their oxidation state from As(III) to As(V), and Cr(VI) to Cr(III), is a potentially effective and attractive strategy for environmental remediation. The coabundance of As(III) and Cr(VI) in natural environments indicates their negligible direct interaction. The addition of H2O2enables and greatly accelerates the simultaneous oxidation of As(III) and reduction of Cr(VI). These reactions are further enhanced at acidic pH and higher concentrations of Cr(VI). However, the presence of ligands (i.e., oxalate, citrate, pyrophosphate) greatly retards …

Light Induced Structures In Liquid Crystalline Side-Chain Polymers With Azobenzene Functional Groups, O. Yaroschuk, Tatiana Sergan, J. Lindau, S. Lee, J. Kelly, Liang-Chy Chien

Liang-Chy Chien

We applied ellipsometry to study the distribution of azobenzene fragments in the films of two types of comblike polymers with azobenzene moieties in the side chains before and after ultraviolet ~UV! light irradiation. The polymer with an alkyl chain at the end of the azobenzene fragment forms structures with preferred homeotropic alignment of the fragments. Irradiation of this polymer with nonpolarized UV light at normal incidence induces a homeotropic alignment of azobenzene fragments. Oblique irradiation induces tilted structures. Polarized UV light irradiation at normal beam incidence induces biaxial structures with a fanlike distribution of azobenzene fragments and preferably out-of-plane alignment. …

Short Pitch Cholesteric Electro-Optical Device Stabilized By Nonuniform Polymer Network, Sang Kim, Liang-Chy Chien

Liang-Chy Chien

We have developed a method for stabilization of the uniform lying helix (ULH) texture of short pitch cholesterics in an electro-optical device, based on the flexoelectro-optic effect in such a texture. By using a small concentration of photoreactive liquid crystal monomer (less than 5 wt. %) and selecting the illumination conditions, we were able to create a nonuniform polymeric network in the liquid crystal bulk (localized essentially at both substrate surfaces) which stabilized efficiently the amplitude and the phase modulation modes of the device. Most importantly, the effect of the residual birefringence of the polymeric network in the field-unwound state …

Structure And Morphology Of Polymer-Stabilized Cholesteric Diffraction Gratings, Shin-Woong Kang, Samuel Sprunt, Liang-Chy Chien

Liang-Chy Chien

We report a study of polymer network morphology in planar diffraction gratings formed from polymer-stabilized cholesteric liquid crystals. Photopolymerizing a mesogenic monomer yields a regular sawtooth morphology, composed of polymer sheets running at an acute angle between thick, uniformly aligned bundles which reside on the opposing substrates. To explain this morphology and evidence of two grating vectors in the diffraction pattern, we propose a model for the liquid-crystal director where out-of-phase twists at the surfaces gear into an interior twist, which has half the period of the surface twist, via splay distortions running between the substrates. The morphology also changes …

Control Of Reflectivity And Bistability In Displays Using Cholesteric Liquid-Crystals, Deng-Ke Yang, John West, Liang-Chy Chien, J. Doane

Liang-Chy Chien

It is demonstrated that the reflective properties and bistability of cholesteric liquid crystals can be controlled by proper surface treatment and dispersed polymers. Dispersing a polymer in the liquid crystal or using a cell with an inhomogeneous surface anchoring creates permanent defects which result in long-term bistability, high contrast at large viewing angles, and gray scale. The wide-angle, reflective feature makes cholesteric materials suitable for displays without backlights and bistability provides flicker-free operation.

Field-Induced And Polymer-Stabilized Two-Dimensional Cholesteric Liquid Crystal Gratings, Shin-Woong Kang, Liang-Chy Chien

Liang-Chy Chien

The authors experimentally demonstrate an electrically switchable gratings based on polymer-stabilized, field-induced two-dimensional square-lattice pattern of a cholesteric liquid crystal. A dependence of the two-dimensional diffraction patterns with the magnitude of applied voltage is observed for before and after the polymer stabilization. The diffraction efficiency reaches 84% calculated for the zero order light intensity at the applied voltage of 0.23 V/mu m for a 10 mu m thick sample.

Dynamical Studies Of Gratings Formed In Polymer-Dispersed Liquid Crystal Films, Andy Fuh, T. Ko, M. Tsai, C. Huang, Liang-Chy Chien

Liang-Chy Chien

The use of polymer-dispersed liquid crystal films to fabricate gratings was demonstrated. The written gratings are permanent, but are electrically switchable. In this article, we report the results obtained from the dynamical studies of gratings formed in polymer-dispersed liquid crystal films having various liquid crystal-polymer mixing ratios. The results showed that during the initial phases of formation, a thermal grating effect dominated. Later, it was offset or quenched by the photopolymerization effect which eventually dominated and determined the characteristics of the final grating.

Photoinduced Three-Dimensional Orientational Order In Side Chain Liquid Crystalline Azopolymers, O. Yaroshchuk, K. Kiselev, Yu. Zakrevskyy, T. Bidna, J. Kelly, Liang-Chy Chien, J. Lindau

Liang-Chy Chien

We apply experimental technique based on the combination of methods dealing with principal refractive indices and absorption coefficients to study the photoinduced three-dimensional (3D) orientational order in the films of liquid crystalline (LC) azopolymers. The technique is used to identify 3D orientational configurations of trans azobenzene chromophores and to characterize the degree of ordering in terms of order parameters. We study two types of LC azopolymers which form structures with preferred in-plane and out-of-plane alignment of azochromophores, respectively. Using irradiation with the polarized light of two different wavelengths, we find that the kinetics of photoinduced anisotropy can be dominated by …

Nematic Director Orientation In A Liquid-Crystal-Dispersed Polymer - A Deuterium Nmr Approach, Ralf Stannarius, G. Crawford, Liang-Chy Chien, J. Doane

Liang-Chy Chien

The nuclear-magnetic-resonance (NMR) technique is employed to liquid-crystal-dispersed-polymer (LCDP) systems. Deuterium NMR is used to determine director distributions in LCDP cells in the presence of a magnetic field. The samples consist of a nematic liquid crystal mixed with small percentages of a monomer that is polymerized under different conditions after dissolving it in the liquid crystal. NMR spectra of the deuterated liquid-crystal molecules give information on orientation and order in such systems. The orientation of the polymer skeleton formed during the polymerization is found to be stable. It determines the orientation of the nematic director even in the presence of …

Municipal Solid Wastes And Water Quality Issues In Nigeria, S Isiorho, D Omole

S Isiorho

No abstract provided.

So You Measured Chemical Parameters In A Well Field And So What?, Sarah Budd, Tammy Lafaucia, S Isiorho

S Isiorho

No abstract provided.

A Multispacecraft Istp Study: Substorm Evolution From The Solar Wind To The Magnetosphere And Ionosphere, T Pulkkinen, D Baker, Niescja Turner, H Singer, J Blake, H Spence, L Frank, J Sigwarth, T Mukai, S Kokubun, R Nakamura, C Russell, H Kawano, F Mozer, J Slavin, R Lepping, R Anderson, G Reeves, L Zelenyi

Niescja E. Turner

An isolated substorm event on May 15, 1996, was recorded by an unprecedented suite of satellites both in the solar wind and in the magnetosphere. We show data from various instruments onboard several ISTP satellites to discuss both the prompt response of the dayside magnetosphere to the changes in the interplanetary magnetic field and the following substorm evolution in the nightside tail.

A Substorm Onset Observed By The Polar Spacecraft In Conjunction With The Image Chain, P Toivanen, D Baker, W Peterson, A Viljanen, Niescja Turner, X Li, C Kletzing

Niescja E. Turner

No abstract provided.

Reply To Comment On "Evaluation Of The Tail Current Contribution To Dst", Niescja Turner, D Baker, T Pulkkinen, R Mcpherron

Niescja E. Turner

Turner et al. [2000] analyzed the contribution of cross-tail currents to the Dst index. In order to estimate this contribution we used modified versions of the Tsyganenko models which had been adjusted to match spacecraft data in the tail, and we isolated a tail region and calculated its influence. We concluded that the tail currents were responsible for around 25% of the Dst response during moderately disturbed times. Maltsev and Ostapenko [2002] conclude that our estimate was low by a factor of 2, owing to that fact that we neglected dayside currents and that the model we used systematically underestimates …

Florida Energy Assurance Plan, Niescja Turner, W Murtagh, K Guthrie, K Nykyri, W Radasky, E Senkowicz

Niescja E. Turner

No abstract provided.

Reconciliation Of The Substorm Onset Determined On The Ground, In The Equatorial Magnetosphere, And At The Polar Spacecraft, P Toivanen, D Baker, W Peterson, H Singer, Niescja Turner, X Li, K Kauristie, M Syrjasuo, A Keiling, C Kletzing, C Russell

Niescja E. Turner

An isolated substorm on Oct. 17, 1997 during a close conjunction of the Polar spacecraft and the ground-based MIRACLE network is studied in detail. We identify signatures of substorm onset in the plasma sheet midway between the ionosphere and the equatorial plasma sheet, determine their timing relative to the ground signatures, and discuss their counterparts on the ground and in the equatorial plasma sheet. The substorm onset is determined as the negative bay onset at 2040:42(≠ 5 sec) UT coinciding with the onset of auroral precipitation, energization of plasma sheet electrons at Polar, and strong magnetic field variations perpendicular to …

The Magnetic Field Induced By A Lightning Strikes Indirect Effect Double Exponential Current Waveform, S Meredith, S Earles, I Kostanic, Niescja Turner

Niescja E. Turner

Problem statement: Develop a new formula which describes the magnetic field induced by a lightning strike's indirect effect double exponential current waveform. Approach: A novel approach for developing a closed-form solution for the magnetic field from the indirect effect double exponential current waveform will be presented. In the literature, models typically employ the pulse waveform to derive the corresponding electromagnetic fields. However, given the Department of Defense (DoD) has incorporated the double exponential current waveform as part of their "Electromagnetic Environmental Effects Requirements For Systems", we felt it important to develop a solution for the magnetic field which utilized this …

Evaluation Of The Tail Current Contribution To Dst, Niescja Turner, D Baker, T Pulkkinen, R Mcpherron

Niescja E. Turner

The Dst index is produced using low-latitude ground magnetic field measurements and frequently is used as an estimate of the energy density of the ring current carried mainly by energetic (∼10-200 keV) ions relatively close to the Earth. However, other magnetospheric current systems can cause field perturbations at the Earth's surface: for example, dayside magnetopause currents are known to contribute to the Dst index. It has also been suggested that the nightside tail current sheet can significantly affect the Dst index during high magnetic activity periods when the currents are intense and flow relatively close to the Earth. In this …