On the detection of characteristic optical emission from electronically coupled nanoemitters

Optical emission from an electronically coupled pair of nanoemitters is investigated, in a new theoretical development prompted by experimental work on oriented semiconductor polymer nanostructures. Three physically distinct mechanisms for photon emission by such a pair, positioned in the near-field, are identified: emission from a pairdelocalized exciton state, emission that engages electrodynamic coupling through quantum interference, and correlated photon emission from the two components of the pair. Each possibility is investigated, in detail, by examination of the emission signal via explicit coupling of the nanoemitter pair with a photodetector, enabling calculations to give predictive results in a form directly tailored for experiment. The analysis incorporates both near- and far-field properties (determined from the detector-pair displacement), so that the framework is applicable not only to a conventional remote detector, but also a near-field microscope setup. The results prove strongly dependent on geometry and selection rules. This work paves the way for a broader investigation of pairwise coupling effects in the optical emission from structured nanoemitter arrays

Unexpected transformation of dissolved phenols to toxic dicarbonyls by hydroxyl radicals and UV light.

Water treatment systems frequently use strong oxidants or UV light to degrade chemicals that pose human health risks. Unfortunately, these treatments can result in the unintended transformation of organic contaminants into toxic products. We report an unexpected reaction through which exposure of phenolic compounds to hydroxyl radicals (•OH) or UV light results in the formation of toxic α,β-unsaturated enedials and oxoenals. We show that these transformation products damage proteins by reacting with lysine and cysteine moieties. We demonstrate that phenolic compounds react with •OH produced by the increasingly popular UV/hydrogen peroxide (H2O2) water treatment process or UV light to form toxic enedials and oxoenals. In addition to raising concerns about potential health risks of oxidative water treatment, our findings suggest the potential for formation of these toxic compounds in sunlit surface waters, atmospheric water, and living cells. For the latter, our findings may be particularly relevant to efforts to understand cellular damage caused by in vivo production of reactive oxygen species. In particular, we demonstrate that exposure of the amino acid tyrosine to •OH yields an electrophilic enedial product that undergoes cross-linking reaction with both lysine and cysteine residues

Integral D-Finite Functions

We propose a differential analog of the notion of integral closure of algebraic function fields. We present an algorithm for computing the integral closure of the algebra defined by a linear differential operator. Our algorithm is a direct analog of van Hoeij's algorithm for computing integral bases of algebraic function fields

Hyper-Rayleigh scattering in centrosymmetric systems

Hyper-Rayleigh scattering (HRS) is an incoherent mechanism for optical second harmonic generation. The frequency-doubled light that emerges from this mechanism is not emitted in a laser-like manner, in the forward direction; it is scattered in all directions. The underlying theory for this effect involves terms that are quadratic in the incident field and involves an even-order optical susceptibility (for a molecule, its associated hyperpolarizability). In consequence, HRS is often regarded as formally forbidden in centrosymmetric media. However, for the fundamental three-photon interaction, theory based on the standard electric dipole approximation, representable as E13, does not account for all experimental observations. The relevant results emerge upon extending the theory to include E12M1 and E12E2 contributions, incorporating one magnetic dipolar or electric quadrupolar interaction, respectively, to a consistent level of multipolar expansion. Both additional interactions require the deployment of higher orders in the multipole expansion, with the E12E2 interaction analogous in rank and parity to a four-wave susceptibility. To elicit the correct form of response from fluid or disordered media invites a tensor representation which does not oversimplify the molecular components, yet which can produce results to facilitate the interpretation of experimental observations. The detailed derivation in this work leads to results which are summarized for the following: perpendicular detection of polarization components both parallel and perpendicular to the pump radiation, leading to distinct polarization ratio results, as well as a reversal ratio for forward scattered circular polarizations. The results provide a route to handling data with direct physical interpretation, to enable the more sophisticated design of molecules with sought nonlinear optical properties

National and Coordinated Approaches to Securities Regulation: The Latest Initiatives in Historical Context

If securities regulation is any indication, few countries in the world take their federalism as seriously as Canada does. Notwithstanding an increasingly globalised world, the central reality of Canadian federalism will continue to influence the enactment and enforcement of effective capital markets regulation. In the latest development, on September 8, 2014 the federal government and four participating provinces announced draft legislation, including a new uniform provincial act and new federal legislation, to establish a new Cooperative Capital Markets Regulator (CCMR). Some provinces are strongly opposed, including Québec, which has promised to challenge the proposed regime on constitutional grounds. This chapter surveys Canadian efforts at nationalisation or coordination of securities regulation over the last eight decades. This historical analysis locates current reform efforts in context and compares those efforts, in detail and on the merits, with prior attempts to establish a national or common regulator, statute, or both. The chapter considers the Supreme Court of Canada’s important 2011 decision in Reference re Securities Act, including the question of exactly what it might mean for the federal government to “manage systemic risk” in the capital markets. The chapter then assesses the options available after the Reference, including but not limited to the proposed CCMR, along with the political, administrative and political considerations that will affect any regime going forward. This is a draft chapter in the fifth edition of Securities Regulation in Canada, now forthcoming (2014). As Governor General of Canada, His Excellency David Johnston has refrained from expressing opinions on matters that are currently under public policy discussion. Any views or recommendations on policy changes in this chapter or in the text as a whole are those of Kathleen Rockwell and Cristie Ford, and should not be attributed to His Excellency. As well, the opinions stated here should not be taken to be those of anyone at the Alberta Securities Commission other than Kathleen Rockwell herself

Discerning leadership perceptions of Central Eurasian managers: an exploratory analysis

This exploratory study examined the responses of Central Eurasian corporate, government, and non-governmental organization managers regarding their perceptions of work-related values of effective organizational leadership. The respondents were participants in a 2-week leadership development program held in Istanbul, Turkey. Two inter-related research questions regarding leadership concepts and challenges were explored through content analysis of program intake interview protocols. The participants’ pre-program perspectives on what constituted effective organizational leadership were found to be consistent with the GLOBE Project’s culturally endorsed leadership dimensions. Moreover, several common patterns of behaviors and challenges were uncovered that could be attributed to particular idiosyncrasies in the sociopolitical/cultural environment of the region

Landscape-Scale Patterns of Fire and Drought on the High Plains, USA

We examine 31 years (1982-2012) of temperature, precipitation and natural wildfire occurrence data for Federal and Tribal lands to determine landscape-scale patterns of drought and fire on the southern and central High Plains of the western United States. The High Plains states of Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas and Wyoming have been in the midst of ongoing extreme drought, experiencing below normal precipitation and above normal temperatures for the past several years. Climate change is predicted to have multiple effects on fire regimes. Longer periods of drought conditions, coupled with hot, dry and windy weather, provide the conditions for wildfire (Ford et al., 2012), and megafires, or large-scale fires that significantly exceed those of recent decades are now occurring in grassland, shrubland and desert ecosystems (Chambers and Pellant, 2008). Our objective is to relate the frequency and size of wildfires to precipitation, temperature and latitudinal gradients to increase understanding of wildfire and drought interactions on the Great Plains in a changing climate