Impact of fuel quality regulation and speed reductions on shipping emissions: implications for climate and air quality

Atmospheric emissions of gas and particulate matter from a large ocean-going container vessel were sampled as it slowed and switched from high-sulfur to low-sulfur fuel as it transited into regulated coastal waters of California. Reduction in emission factors (EFs) of sulfur dioxide (SO?), particulate matter, particulate sulfate and cloud condensation nuclei were substantial (≥ 90%). EFs for particulate organic matter decreased by 70%. Black carbon (BC) EFs were reduced by 41%. When the measured emission reductions, brought about by compliance with the California fuel quality regulation and participation in the vessel speed reduction (VSR) program, are placed in a broader context, warming from reductions in the indirect effect of SO? would dominate any radiative changes due to the emissions changes. Within regulated waters absolute emission reductions exceed 88% for almost all measured gas and particle phase species. The analysis presented provides direct estimations of the emissions reductions that can be realized by California fuel quality regulation and VSR program, in addition to providing new information relevant to potential health and climate impact of reduced fuel sulfur content, fuel quality and vessel speed reductions.     

High throughput assay of diffusion through Cx43 gap junction channels with a microfluidic chip

This paper describes a microfluidic-based assay capable of measuring gap-junction mediated dye diffusion in cultured cells. The technique exploits multistream laminar flow to selectively expose cells to different environments, enabling continuous loading of cells in one compartment while monitoring, in real time, dye diffusion into cells of a neighboring compartment. A simple one-dimensional diffusion model fit to the data extracted the diffusion coefficient of four different dyes, 5-(6)-carboxyfluorescein, 5-chloromethylfluorescein, Oregon green 488 carboxylic acid, and calcein. Different inhibitors were assayed for their ability to reduce dye coupling. The chip can screen multiple inhibitors in parallel in the same cell preparation, demonstrating its potential for high throughput. The technique provides a convenient method to measure gap junction mediated diffusion and a screen for drugs that affect gap junction communication.     

Soft X-ray induced photoreduction of organic Cu(II) compounds probed by X-ray absorption near-edge (XANES) spectroscopy

Photoreduction is a major obstacle for using the X-ray absorption near-edge structure (XANES) fingerprint to perform metal speciation at the molecular level in biological and environmental samples, especially for metalloproteins. In this study, soft X-ray induced photoreduction was observed in organic Cu(II) compounds during XANES measurements in a third-generation synchrotron source. Next Cu L(3)-edge, O K-edge, and C K-edge XANES spectroscopy, together with the scanning transmission X-ray microscopy (STXM), were used to probe the specific radiation damage processes of Cu acetate with similar local structures to Cu metalloproteins. Breakup of the Cu-Cu bond was hypothesized for the initial photoreduction of Cu acetate. The following radiation damage of Cu acetate produced CuO and an organic Cu(I) compound with a C═C bond, and the further photoreduction of the resulting CuO to Cu metal was also demonstrated. Our results indicated the importance of consideration of photoreduction during soft XANES measurements for the solid state compounds with high valence metals. Reducing the radiation dose to ~0.1 MGy effectively prevented the photoreduction of organic Cu(II) compounds during these measurements. This proposed radiation damage mechanism in Cu acetate may be generally useful in explaining the photoreduction process in Cu metalloproteins.     

吉木萨尔凹陷页岩油密切割压裂多簇裂缝竞争扩展模拟

针对吉木萨尔凹陷芦草沟组页岩油储层地质特征,建立了重点改造井的密切割体积压裂裂缝扩展三维离散元数值模型,模型依据成像测井资料设置了随机分布的天然层理和高角度裂缝,依据纵向分层数据设置了小层及层间界面.模型模拟了不同分簇数和簇间距下的复杂裂缝扩展过程,分析了密切割体积压裂改造过程中多簇裂缝竞争扩展规律和改造后裂缝系统的立...     

Radiolocation System Using Distributed Sensor Array Onboard a High Altitude Aerial Vehicle

High altitude aerial vehicle, or platform, is expected to help public safety by monitoring various kinds of radio transmission with a high resolution, such as search and rescue signals and emergency calls, in addition to the optical monitoring and wireless relay. Unmanned aircrafts or airships are the candidates for the platform vehicle with those purposes. This paper proposes a system that estimates the location of transmitter sources on the ground by a large-aperture sensor array mounted on the high altitude aerial vehicle with a flexible structure and discusses on a real time calibration method for the position and internal phase errors of sensor elements.     

Three-dimensional reconstruction of the fast-start swimming kinematics of densely schooling fish

Information transmission via non-verbal cues such as a fright response can be quantified in a fish school by reconstructing individual fish motion in three dimensions. In this paper, we describe an automated tracking framework to reconstruct the full-body trajectories of densely schooling fish using two-dimensional silhouettes in multiple cameras. We model the shape of each fish as a series of elliptical cross sections along a flexible midline. We estimate the size of each ellipse using an iterated extended Kalman filter. The shape model is used in a model-based tracking framework in which simulated annealing is applied at each step to estimate the midline. Results are presented for eight fish with occlusions. The tracking system is currently being used to investigate fast-start behaviour of schooling fish in response to looming stimuli.     

High-throughput microwave synthesis and characterization of NiO nanoplates for supercapacitor devices

In order to produce economically viable supercapacitor devices for electrical energy storage, low cost, and high throughput methods must be developed. We developed a microwave based synthesis for the formation of β-Ni(OH)₂ for the formation of nickel oxide nanoplates. These nanoplates have shown excellent properties as pseudocapacitive devices with high-specific capacitance. Novel to this article is the use of a microwave reactor which enables a growth process of only 10 min in duration as compared to previous reports requiring a 24 h period. The resulting NiO nanoplates were fully characterized by electron microscopy, electron diffraction, energy dispersive X-ray spectroscopy, UV–Vis spectroscopy, thermo gravimetric analysis, and surface area and porosity measurements. Nanoplates formed using the microwave reactor is similar to those formed by hydrothermal processes. NiO-single walled carbon nanotube composites were made without any binder and the specific capacitance was measured using charge discharge techniques.     

Inclusion without assimilation: Science education from an anthropological and metacognitive perspective

Abstract:

This article addresses some of the problems inherent both in traditional didactic science teaching and in approaches based on theories of conceptual change. The author argues that the twin pitfalls of exclusion from science education and assimilation into a culture of compliance can be avoided by helping students to acquire a better understanding of science (through an anthropological approach) and a better understanding of themselves as learners and as science initiates.     

Rencontre entre deux disciplines scolaires,biologie et mathématiques première approche des enjeux didactiques de la formation des enseignants de biologie

Abstract

While the educational value of whalewatching has often been proclaimed, there has been little research on the topic. This article, based on a case study conducted in Tadoussac, Quebec, focuses on whalewatching's ability to act as a form of critical science education. Discussion of learning outcomes and learning desires of 31 whalewatchers forms the core of the article. Key issues that emerge include the need for interpreter training, epistemic responsibility of scientists, and the role of conservation and advocacy in whalewatching interpretation. While the whalewatching experience described in this case study did not live up its potential as a form of critical science education, we believe that such goals are worth pursuing and may enhance whalewatching interpretation in the future. Further, we see whalewatching (and, by implication, other forms of nature experience) as a significant adjunct to formal science education because it creates space for the strong affective component essential to effecting the transition from caring about to caring for the environment, and because it can be a site for a more explicitly politicized type of science education than is generally possible in today's increasingly corporatized school system.