A chemical ionization mass spectrometry method for the online analysis of organic aerosols

A new technique employing chemical ionization mass spectrometry (CIMS) is described that allows the composition of organic particles to be determined on the time scale of seconds. With this Aerosol CIMS technique, particles are vaporized thermally at temperatures up to 480 degrees C, and the resulting vapor is chemically ionized and detected with a quadrupole mass spectrometer. The separation of the vaporization and ionization steps allows greater control and more flexibility for the detection of condensed phases than with other chemical ionization methods. Consequently, composition can be correlated to volatility, providing an additional dimension of information. The use of a variety of positive and negative reagent ions, such as H(+)(H(2)O)(2), H(+)(CH(3)OH)(2), NO(+), O(2)(+), O(2)(-), F(-), and SF(6)(-), offers flexibility in the detection sensitivity and specificity. Furthermore, the degree of fragmentation of the resulting ion can be controlled, providing more straightforward identification and quantification than with other commonly used methods, such as electron impact ionization. Examples are given of the detection of aerosols consisting of organics with various functionalities, including alkanes, alkenes, alcohols, aldehydes, ketones, and carboxylic acids. Applications of this technique to laboratory studies of atmospherically relevant aerosol reactions are discussed.     

Replication Requirements in Mobile Environments

Replication is extremely important in mobile environments because nomadic users require local copies of important data. However, today's replication systems are not mobile-ready. Instead of improving the mobile user's environment, the replication system actually hinders mobility and complicates mobile operation. Designed for stationary environments, the replication services do not and cannot provide mobile users with the capabilities they require. Replication in mobile environments requires fundamentally different solutions than those previously proposed, because nomadicity presents a fundamentally new and different computing paradigm. Here we outline the requirements that mobility places on the replication service, and briefly describe ROAM, a system designed to meet those requirements.     

Information technology (IT) in Saudi Arabia: Culture and the acceptance and use of IT

The unified theory of acceptance and use of technology (UTAUT), a model of the user acceptance of IT, synthesizes elements from several prevailing user acceptance models. It has been credited with explaining a larger proportion of the variance of ‘intention to use’ and ‘usage behavior’ than do preceding models. However, it has not been validated in non-Western cultures. Using a survey sample collected from 722 knowledge workers using desktop computer applications on a voluntary basis in Saudi Arabia, we examined the relative power of a modified version of UTAUT in determining ‘intention to use’ and ‘usage behavior’. We found that the model explained 39.1% of intention to use variance, and 42.1% of usage variance. In addition, drawing on the theory of cultural dimensions, we hypothesized and tested the similarities and differences between the North American and Saudi validations of UTAUT in terms of cultural differences that affected the organizational acceptance of IT in the two societies.     

用于图像传感器制造的光刻技术

引言任何一种数字成像的核心都是图像传感器。它的基本结构包括一个能把光转换为图像的有源像素矩阵。数码相机和带相机的移动电话带动了图像传感器需求市场的快速增长,它们已成为主要IC制造商大量生产的产品之一。制造成像阵列通常采用两种主要的工艺技术——电荷耦合器件(CCD)和CMOS图像传感器(CIS)。在形成工艺层次组合和电学设计方面,这两种技术有很大差别。但是,两者都需要优化,以俘获到达的光线,并将其更有效地转化为电信号。CCD器件在象素区把光子转换为电荷。CIS器件则可以看作为改进的存储器单元,每一单元包含一个可以产生…     

Computer-assisted intervention improves patient-centered diabetes care by increasing autonomy support.

Objective: To determine if a patient-centered, computer-assisted diabetes care intervention increased perceived autonomy support, perceived competence (from self-determination theory), and if these constructs mediated the effect of the intervention on ADA/NCQA recommended diabetes care outcomes. Design: A randomized controlled trial of 866 adult type 2 diabetes patients in heterogeneous primary care settings in Colorado. Main Outcome Measures: Perceived autonomy support, perceived competence, patient satisfaction, glycemic control (HbA1c), ratio of total to HDL cholesterol, diabetes distress, and depressive symptoms. Results: The computer-assisted intervention increased patient perception of autonomy support relative to a computer-based control condition ( p = .05). Change in perceived competence partially mediated the effects of increased autonomy support on the change in lipids, diabetes distress, and depressive symptoms. The construct of autonomy support was found to be separate from that of patient satisfaction. Conclusions: A patient-centered, computer-assisted intervention was effective in improving diabetes self-management outcomes, in part, because it increased patients' perception that their autonomy was supported which changed perceived competence. These findings support the self-determination model for health behavior change and the chronic care model and support the further study of the use of these technologies to motivate patients to improve their health outcomes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A question of belonging: Race, social fit, and achievement.

Stigmatization can give rise to belonging uncertainty. In this state, people are sensitive to information diagnostic of the quality of their social connections. Two experiments tested how belonging uncertainty undermines the motivation and achievement of people whose group is negatively characterized in academic settings. In Experiment 1, students were led to believe that they might have few friends in an intellectual domain. Whereas White students were unaffected, Black students (stigmatized in academics) displayed a drop in their sense of belonging and potential. In Experiment 2, an intervention that mitigated doubts about social belonging in college raised the academic achievement (e.g., college grades) of Black students but not of White students. Implications for theories of achievement motivation and intervention are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Understanding barriers to home‐based and self‐care in‐center hemodialysis

Despite superior outcomes and lower associated costs, relatively few patients with end‐stage renal disease undergo self‐care or home hemodialysis. Few studies have examined patient‐ and physician‐specific barriers to self‐care and home hemodialysis in the modern era. The degree to which innovative technology might facilitate the adoption of these modalities is unknown. We surveyed 250 patients receiving in‐center hemodialysis and 51 board‐certified nephrologists to identify key barriers to adoption of self‐care and home hemodialysis. Overall, 172 (69%) patients reported that they were “likely” or “very likely” to consider self‐care hemodialysis if they were properly trained on a new hemodialysis system designed for self‐care or home use. Nephrologists believed that patients were capable of performing many dialysis‐relevant tasks, including: weighing themselves (98%), wiping down the chair and machine (84%), clearing alarms during treatment (53%), taking vital signs (46%), and cannulating vascular access (41%), but thought that patients would be willing to do the same in only 69%, 34%, 31%, 29%, and 16%, respectively. Reasons that nephrologists believe patients are hesitant to pursue self‐care or home hemodialysis do not correspond in parallel or by priority to reasons reported by patients. Self‐care and home hemodialysis offer several advantages to patients and dialysis providers. Overcoming real and perceived barriers with new technology, education and coordinated care will be required for these modalities to gain traction in the coming years.     

Object-based change detection

Characterizations of land-cover dynamics are among the most important applications of Earth observation data, providing insights into management, policy and science. Recent progress in remote sensing and associated digital image processing offers unprecedented opportunities to detect changes in land cover more accurately over increasingly large areas, with diminishing costs and processing time. The advent of high-spatial-resolution remote-sensing imagery further provides opportunities to apply change detection with object-based image analysis (OBIA), that is, object-based change detection (OBCD). When compared with the traditional pixel-based change paradigm, OBCD has the ability to improve the identification of changes for the geographic entities found over a given landscape. In this article, we present an overview of the main issues in change detection, followed by the motivations for using OBCD as compared to pixel-based approaches. We also discuss the challenges caused by the use of objects in change detection and provide a conceptual overview of solutions, which are followed by a detailed review of current OBCD algorithms. In particular, OBCD offers unique approaches and methods for exploiting high-spatial-resolution imagery, to capture meaningful detailed change information in a systematic and repeatable manner, corresponding to a wide range of information needs.