The Characterization of Surface Variegation Effects on Remote Sensing

Improvements in remote sensing capabilities hinge very directly upon attaining an understanding of the physical processes contributing to the measurements. In order to devise new measurement strategies and to learn better techniques for processing remotely gathered data, it is necessary to understand and to characterize the complex radiative interactions of the atmosphere-surface system. In particular, it is important to understand the role of atmospheric structure, ground reflectance inhomogeneity and ground bidirectional reflectance type. The goals, then, are to model, analyze, and parameterize the observable effects of three dimensional atmospheric structure and composition and two dimensional variations in ground albedo and bidirectional reflectance. To achieve these goals, a Monte Carlo radiative transfer code is employed to model and analyze the effects of many of the complications which are present in nature

Oxygen and carbon impurities and related defects in silicon

Oxygen and carbon are the predominant impurities in Czochralski-grown silicon. The incorporation of oxygen and carbon during crystal growth is reviewed and device effects are discussed. Methods for controlling oxygen and carbon incorporation during crystal growth are discussed and results supporting a segregation coefficient of k=0.5 for oxygen are presented. The nucleation and precipitation behavior of oxygen is complex. Temperature and doping level effects which add insight into the role of point defects in the nucleation process are highlighted. In general, precipitation is found to be retarded in N+ and P+ silicon. The types and quantities of defects resulting from the oxygen precipitates is of interest as they are technologically useful in the process called intrinsic gettering. A comparison is made between the available defect sites and the quantities of metallic impurities present in a typical wafer which need to be gettered. Finally, a discussion of the denuded-zone, intrinsic-gettered (DZ-IG) structure on device properties is presented

Ground effects on Loran-C signals

In conjunction with the test and evaluation of the position fixing capabilities of the Army Manpack Loran Receiver AN/PSN-6, an extensive series of time difference and signal amplitude measurements were made within a 100 km map grid square encompassing Fort Monmouth, New Jersey. The test location is within the coverage area of the East Coast Loran-C Chain. The data were used to develop a simple smooth-earth model for the test area as well as to estimate the magnitude and distributions of deviations from this model. Local propagation processes associated with topographic features and the grid of overhead wires in the test area are shown to contribute to the deviations from the model

Scientific data and its limits: rethinking the use of evidence in local climate change policy

Climate policy is typically seen as informed by scientific evidence that anthropogenic carbon emissions require reducing in order to avoid dangerous consequences. However, agreement on these matters has not translated into effective policy. Using interviews with local authority officials in the UK's East Midlands region, this paper argues that the ideas, arguments and data informing local climate policy have been grounded in evidence from the natural sciences. Focusing on carbon emissions data demonstrated a consensus around scientific knowledge, not local policy responses to this knowledge. Acknowledging this 'mistaken consensus' provides the potential to utilise evidence more attentive to local contexts

Trouble in the trough : how uncertainties were downplayed in the UK’s science advice on Covid-19

The 2020 Covid-19 pandemic has forced science advisory institutions and processes into an unusually prominent role, and placed their decisions under intense public, political and media scrutiny. In the UK, much of the focus has been on whether the government was too late in implementing its lockdown policy, resulting in thousands of unnecessary deaths. Some experts have argued that this was the result of poor data being fed into epidemiological models in the early days of the pandemic, resulting in inaccurate estimates of the virus’s doubling rate. In this article, I argue that a fuller explanation is provided by an analysis of how the multiple uncertainties arising from poor quality data, a predictable characteristic of an emergency situation, were represented in the advice to decision makers. Epidemiological modelling showed a wide range of credible doubling rates, while the science advice based upon modelling presented a much narrower range of doubling rates. I explain this puzzle by showing how some science advisors were both knowledge producers (through epidemiological models) and knowledge users (through the development of advice), roles associated with different perceptions of scientific uncertainty. This conflation of experts’ roles gave rise to contradictions in the representation of uncertainty over the doubling rate. Role conflation presents a challenge to science advice, and highlights the need for a diversity of expertise, a structured process for selecting experts, and greater clarity regarding the methods by which expert consensus is achieved. The analysis indicates an urgent research agenda that can help strengthen the UK science advice system after Covid-19

Running the rat race

No abstrac

Synthesis and Characterization of Imidazolium Salt Derivatives for Anti-Tumor Activity

Several aldehydes (butanal, pentanal, hexanal, 4-hydroxybenzaldehyde) were reacted with 1,3-bis(naphthalen-2-ylmethyl)-imidazolium bromide (1) to produce novel C2 substituted imidazolium salts for the potential use against non-small cell lung cancer in humans. Compounds 2-(1-hydroxypentyl)-1,3-bis(naphthalen-2-ylmethyl)-imidazolium bromide (3) and 2-(1-hydroxyhexyl)-1,3-bis(naphthalen-2-ylmethyl)-imidazolium bromide (5) were successfully synthesized with structures supported by NMR and mass spectrometry. Characterization by 1H NMR showed evidence of 1 in both compounds. The tumor cell growth inhibition of 3 against non-small cell lung cancer lines NCI-A549, NCI-H460, HCC827, and NCI-H1975 was tested and found to be comparable to cisplatin as measured by MTT assay. Compounds were compared by their IC50 values against a panel of human cancer cell lines. The IC50 values for 3 were: 9 μM for A549 cells, 7 μM for H460 cells, 5 μM for HCC827 cells, and 3 μM for H1975 cells. Cisplatin had IC50 values in the range of 3-8 μM for these cell types, indicating that our compound had similar efficiency to a current chemotherapeutic agent. Similar IC50 values for 1 in the literature suggest C2 substituents may not significantly affect tumor cell growth inhibition.1 This may allow for different functional groups to be substituted at the C2 position in order to optimize properties such as water solubility and toxicity while not hindering therapeutic benefits