Isotope Effects on Metastable Transitions. IV. Isotopic Methanols

Metastable transitions were studied in the mass spectra of methanol and deuterated methanols in a sector mass spectrometer. The relative abundances of the various metastable ions at 70eV were determined. The intensities are in good agreement with those obtained employing a double-focussing instrument operating in the metastable mode. There is a strong isotope effect on the intensity of the anomalous parent-ion metastable transition. This transition and the one leading to a “flat top” metastable peak were studied carefully. Appearance potentials were determined for the ions involved, by the RPD method and for the metastables themselves by conventional techniques. Metastable ion decay curves were obtained using an improved pulsed ion source. The results are discussed in terms of the quasi-equilibrium theory of mass spectra.     

The effect of alcohol, THC and their combination on perceived effects, willingness to drive and performance of driving and non-driving tasks

Background

Driving under the influence of drugs (DUID) is one of the main causes of car accidents. Alcohol and marijuana are the most popular drugs among recreational users. Many classify these drugs as “Light” drugs and therefore allow themselves to drive after consuming them.

Objective

The study had two main objectives: 1) to investigate the effect of alcohol (BAC = 0.05%), THC (13 mg) and their combination on driving and non-driving tasks. 2) to investigate the extent to which people are willing to drive based on their subjective sensations and their perceived effects of the drugs.

Method

7 healthy men and 5 healthy women, ages 24-29, all recreational users of alcohol and marijuana, completed 5 experimental sessions. Sessions included: drinking and smoking placebo, drinking alcohol and smoking placebo, drinking placebo and smoking THC, drinking alcohol and smoking THC, drinking placebo and smoking placebo 24 hours after drinking alcohol and smoking THC. Three types of measures were used: subjective perceptions (with questionnaires), performance parameters of the driving and non-driving tasks (arithmetic task and a secondary target detection task) and physiological changes (heart rate).

Results

Overall, the combination of alcohol and THC had the most intense effect after intake. This effect was reflected in performance impairments observed in the driving and non-driving tasks, in the subjective sensations after intake, and in the physiological measures. Despite significant differences in the size of the effects after the various treatments, there were no differences in the distances subjects were willing to drive while under the influence on each of the treatments.     

Addressing uncertainty in fecal indicator bacteria dark inactivation rates

Assessing the potential threat of fecal contamination in surface water often depends on model forecasts which assume that fecal indicator bacteria (FIB, a proxy for the concentration of pathogens found in fecal contamination from warm-blooded animals) are lost or removed from the water column at a certain rate (often referred to as an “inactivation” rate). In efforts to reduce human health risks in these water bodies, regulators enforce limits on easily-measured FIB concentrations, commonly reported as most probable number (MPN) and colony forming unit (CFU) values. Accurate assessment of the potential threat of fecal contamination, therefore, depends on propagating uncertainty surrounding “true” FIB concentrations into MPN and CFU values, inactivation rates, model forecasts, and management decisions. Here, we explore how empirical relationships between FIB inactivation rates and extrinsic factors might vary depending on how uncertainty in MPN values is expressed. Using water samples collected from the Neuse River Estuary (NRE) in eastern North Carolina, we compare Escherichia coli (EC) and Enterococcus (ENT) dark inactivation rates derived from two statistical models of first-order loss; a conventional model employing ordinary least-squares (OLS) regression with MPN values, and a novel Bayesian model utilizing the pattern of positive wells in an IDEXX Quanti-Tray^®/2000 test. While our results suggest that EC dark inactivation rates tend to decrease as initial EC concentrations decrease and that ENT dark inactivation rates are relatively consistent across different ENT concentrations, we find these relationships depend upon model selection and model calibration procedures. We also find that our proposed Bayesian model provides a more defensible approach to quantifying uncertainty in microbiological assessments of water quality than the conventional MPN-based model, and that our proposed model represents a new strategy for developing robust relationships between environmental factors and FIB inactivation rates, and for reducing uncertainty in water resource management decisions.     

Epoxy silicone based matrix materials for two-photon patterning of optical waveguides

3D polymeric optical waveguides play an intrinsic role in a rapidly developing area of broadband communications. Advances in the field of electronics means there is a greater demand for higher speeds, larger data storage, smaller components and the improvement in the design of integrated optical circuits. Two-photon photopolymerisation (2PP) is a promising three-dimensional microfabrication technique, which can be used to produce structures in the sub-micron region. With the use of near-infrared (NIR) lasers, 3D optical waveguides can be fabricated in polymer-based matrix materials, based on the increase of the refractive index in the vicinity of the laser focus.The development of a new polysiloxane material, used in the study of the integration of optical interconnects on printed circuit boards is presented. The desirable properties of epoxy functional silicones crosslinked with diamines deem them suitable for such applications. An epoxy terminated polysiloxane; crosslinked with an aminopropyl disiloxane has been developed as a suitable material for the fabrication of optical waveguides by two-photon absorption (TPA). The material fulfils a number of requirements including a good refractive index contrast between the matrix material and inscribed waveguide, full flexibility and high thermal stability.The matrix material was characterised by Fourier transform infrared spectroscopy (FTIR) and thermal gravimetric analysis (TGA) The optical waveguides were characterised by phase contrast microscopy, and were directly integrated onto specially designed PCB’s by correctly positioning waveguide bundles between optoelectronic components using TPA, making it possible to detect transmitted photocurrents.     

Permeable porous 1–3 nm thick overoxidized polypyrrole films on nanostructured carbon fiber microdisk electrodes

Ionically conducting 1–3 nm thick porous films of overoxidized polypyrrole (OPPY) were electrodeposited on nanostructured 7 μm diameter carbon fiber microdisk electrodes. The microdisk electrodes were fabricated from two types of polyacrylonitrile (PAN) carbon fibers, PAN T650 and PAN HCB. The electrodes were nanostructured by electrochemical etching of the microdisk electrode surface. Ultrathin porous polypyrrole (PPY) films were electrodeposited by the electropolymerization of pyrrole (PY) to PPY by a short (10 ms) single potential pulse. During the electropolymerization, the polymer “precipitated” on the nanostructured surface producing ultrathin porous film. OPPY films were fabricated by constant potential overoxidation of PPY.In steady-state voltammetry of ferricyanide, the nanostructured electrodes behave as a random array of microscopic nodules and pores. At potential scan rates of 0.050 V s⁻¹ diffusion fields at the 300–600 nm nodules on the 7 μm diameter microdisk electrode overlap. The surface area of the electroactive nanofeatures decreases after deposition of insulating OPPY. Kinetics of ferricyanide at bare and OPPY-coated nanostructured electrodes reflect the electrode surface area, as predicted by the model for charge transfer at a partially blocked surface. A model reflecting the 58–94% coverage of the nanostructured electrodes by OPPY was developed to address the high permeability of the porous OPPY-coated microdisk electrodes.     

时尚先锋 尤物横行

远在2004年，CHANEL就耗资6000万美元制作了一则两分钟的广告，主角是CHANEL5NO°香水，配角是刚刚获得奥斯卡影后的妮可·基德曼，导演是曾执导过《红磨坊》的澳大利亚著名导演巴兹·吕尔曼，该广告虽然只有两分钟长，却请来了250个群众演员、特技演员，用了价值3000万美元的珠宝做道具。投入超过了好莱坞的许多电影，据说妮可·基德曼花了4天时间得到的报酬高达500万美元。     

A prospective study of relationships between propositions about risk and driver speeding

Risk propositions are specific and modifiable hypotheses that people hold about the outcomes of risk-taking behavior. According to fuzzy trace theory (FTT), risk propositions arise from the subjective and idiosyncratic interpretations that people make about the meaning of risk information, and form the primary basis of decision-making. A community sample of 255 drivers was interviewed at baseline (T1), 6 weeks after baseline (T2) and 14 weeks after baseline (T3). We tested whether propositions about speeding-related risk at time 1 (T1) would predict speeding at time 3 (T3), controlling perceptions of speeding-related danger and other speeding-related variables (the perceived possibility of being caught and the enjoyment and excitement to be gained from speeding) measured at time 2 (T2). We also tested whether relationships between T1 propositions and T3 speeding would be mediated by T2 perceptions of danger. T1 propositions predicted T3 speeding independently of the control variables, and we also found evidence consistent with mediation by T2 danger. In line with FTT, risk propositions were not scaleable as a single dimension, but generally predicted speeding as independent entities. Taken together these findings support the view that drivers perceive speeding risk as a series of potentially modifiable propositions which may have item-specific influences on speeding behavior.     

Using data mining for digital ink recognition: Dividing text and shapes in sketched diagrams

The low accuracy rates of text-shape dividers for digital ink diagrams are hindering their use in real world applications. While recognition of handwriting is well advanced and there have been many recognition approaches proposed for hand drawn sketches, there has been less attention on the division of text and drawing ink. Feature based recognition is a common approach for text-shape division. However, the choice of features and algorithms are critical to the success of the recognition. We propose the use of data mining techniques to build more accurate text-shape dividers. A comparative study is used to systematically identify the algorithms best suited for the specific problem. We have generated dividers using data mining with diagrams from three domains and a comprehensive ink feature library. The extensive evaluation on diagrams from six different domains has shown that our resulting dividers, using LADTree and LogitBoost, are significantly more accurate than three existing dividers.