Novel insights on new particle formation derived from a pan-european observing system.

The formation of new atmospheric particles involves an initial step forming stable clusters less than a nanometre in size (<~1 nm), followed by growth into quasi-stable aerosol particles a few nanometres (~1-10 nm) and larger (>~10 nm). Although at times, the same species can be responsible for both processes, it is thought that more generally each step comprises differing chemical contributors. Here, we present a novel analysis of measurements from a unique multi-station ground-based observing system which reveals new insights into continental-scale patterns associated with new particle formation. Statistical cluster analysis of this unique 2-year multi-station dataset comprising size distribution and chemical composition reveals that across Europe, there are different major seasonal trends depending on geographical location, concomitant with diversity in nucleating species while it seems that the growth phase is dominated by organic aerosol formation. The diversity and seasonality of these events requires an advanced observing system to elucidate the key processes and species driving particle formation, along with detecting continental scale changes in aerosol formation into the future.

Physical and chemical processes of air masses in the Aegean Sea during Etesians: Aegean-GAME airborne campaign.

High-resolution measurements of gas and aerosols' chemical composition along with meteorological and turbulence parameters were performed over the Aegean Sea (AS) during an Etesian outbreak in the framework of the Aegean-GAME airborne campaign. This study focuses on two distinct Etesian patterns, with similarities inside the Marine Atmospheric Boundary Layer (MABL) and differences at higher levels. Under long-range transport and subsidence the pollution load is enhanced (by 17% for CO, 11% for O3, 28% for sulfate, 62% for organic mass, 47% for elemental carbon), compared to the pattern with a weaker synoptic system. Sea surface temperature (SST) was a critical parameter for the MABL structure, turbulent fluxes and pollutants' distribution at lower levels. The MABL height was below 500 m asl over the eastern AS (favoring higher accumulation), and deeper over the western AS. The most abundant components of total PM1 were sulfate (40-50%) and organics (30-45%). Higher average concentrations measured over the eastern AS (131 ± 76 ppbv for CO, 62.5 ± 4.1 ppbv for O3, 5.0 ± 1.1 µg m(-3) for sulfate, 4.7 ± 0.9 µg m(-3) for organic mass and 0.5 ± 0.2 µg m(-3) for elemental carbon). Under the weaker synoptic system, cleaner but more acidic air masses prevailed over the eastern part, while distinct aerosol layers of different signature were observed over the western part. The Aitken and accumulation modes contributed equally during the long-range transport, while the Aitken modes dominated during local or medium range transport.

Evolution of organic aerosols in the atmosphere.

Organic aerosol (OA) particles affect climate forcing and human health, but their sources and evolution remain poorly characterized. We present a unifying model framework describing the atmospheric evolution of OA that is constrained by high-time-resolution measurements of its composition, volatility, and oxidation state. OA and OA precursor gases evolve by becoming increasingly oxidized, less volatile, and more hygroscopic, leading to the formation of oxygenated organic aerosol (OOA), with concentrations comparable to those of sulfate aerosol throughout the Northern Hemisphere. Our model framework captures the dynamic aging behavior observed in both the atmosphere and laboratory: It can serve as a basis for improving parameterizations in regional and global models.

Chemical and microphysical characterization of ambient aerosols with the aerodyne aerosol mass spectrometer.

The application of mass spectrometric techniques to the real-time measurement and characterization of aerosols represents a significant advance in the field of atmospheric science. This review focuses on the aerosol mass spectrometer (AMS), an instrument designed and developed at Aerodyne Research, Inc. (ARI) that is the most widely used thermal vaporization AMS. The AMS uses aerodynamic lens inlet technology together with thermal vaporization and electron-impact mass spectrometry to measure the real-time non-refractory (NR) chemical speciation and mass loading as a function of particle size of fine aerosol particles with aerodynamic diameters between approximately 50 and 1,000 nm. The original AMS utilizes a quadrupole mass spectrometer (Q) with electron impact (EI) ionization and produces ensemble average data of particle properties. Later versions employ time-of-flight (ToF) mass spectrometers and can produce full mass spectral data for single particles. This manuscript presents a detailed discussion of the strengths and limitations of the AMS measurement approach and reviews how the measurements are used to characterize particle properties. Results from selected laboratory experiments and field measurement campaigns are also presented to highlight the different applications of this instrument. Recent instrumental developments, such as the incorporation of softer ionization techniques (vacuum ultraviolet (VUV) photo-ionization, Li+ ion, and electron attachment) and high-resolution ToF mass spectrometers, that yield more detailed information about the organic aerosol component are also described.

Street canyon aerosol pollutant transport measurements.

Current understanding of dispersion in street canyons is largely derived from relatively simple dispersion models. Such models are increasingly used in planning and regulation capacities but are based upon a limited understanding of the transport of substances within a real canyon. In recent years, some efforts have been made to numerically model localised flow in idealised canyons (e.g., J. Appl. Meteorol. 38 (1999) 1576-89) and stepped canyons (Assimakopoulos V. Numerical modelling of dispersion of atmospheric pollution in and above urban canopies. PhD thesis, Imperial College, London, 2001) but field studies in real canyons are rare. To further such an understanding, a measurement campaign has been conducted in an asymmetric street canyon with busy one-way traffic in central Manchester in northern England. The eddy correlation method was used to determine fluxes of size-segregated accumulation mode aerosol. Measurements of aerosol at a static location were made concurrently with measurements on a platform lift giving vertical profiles. Size-segregated measurements of ultrafine and coarse particle concentrations were also made simultaneously at various heights. In addition, a small mobile system was used to make measurements of turbulence at various pavement locations within the canyon. From this data, various features of turbulent transport and dispersion in the canyon will be presented. The concentration and the ventilation fluxes of vehicle-related aerosol pollutants from the canyon will be related to controlling factors. The results will also be compared with citywide ventilation data from a separate measurement campaign conducted above the urban canopy.

Laparoscopic radical nephrectomy.

Laparoscopic radical nephrectomy has gained in popularity as an accepted treatment modality for localized renal cell carcinoma at many centers worldwide. Laparoscopic radical nephrectomy may be performed via a transperitoneal or retroperitoneal approach. Mostly, the transperitoneal approach is used. Current indications for laparoscopic radical nephrectomy include patients with T(1)-T(3a)N(0)M(0) renal tumors. Herein, transperitoneal as well as retroperitoneal laparoscopic approaches are described. Surgical outcomes and complications from published series are reviewed with comparison to open surgery. Special related concerns as oncologic principles, organ retrieval, lymphadenectomy, and concomitant adrenalectomy are addressed. In conclusion, laparoscopic radical nephrectomy is now established with considerable advantages; decreased postoperative morbidity, decreased analgesic requirements, improved cosmesis, shorter hospital stay and convalescence. Although no long-term follow-up is available, short and intermediate follow-up results confirm the effectiveness of laparoscopic radical nephrectomy.

Virtual endoscopy in urology.

Recent years have seen notable advances in virtual reality technology and increased interest in potential medical applications. Computed tomography and magnetic resonance imaging data sets, historically viewed as axial images, may now be used to construct a virtual reality endoscopic image, and navigator software systems allow the operator to 'fly' through the urinary tract. Technological evolution has improved the quality of reconstruction, as this is dependent on the software and data set, allowing virtual reality to begin to challenge endoscopic evaluation. This review describes the evolution of virtual reality in urology and the milestones of its current clinical use. Applications may become widespread in the diagnostic evaluation of common urological symptoms, the planning of surgery and the training of future urologists.

Spatial awareness in urologists: are they different?

OBJECTIVE: To compare innate spatial awareness skills, using the MIST-VR system (Ethicon Ltd, Edinburgh, a computer-based virtual reality system that objectively tests spatial awareness) among three groups of people (consultant urologists, urological trainees and controls who were not surgeons), because urological surgeons require spatial awareness for endoscopic and laparoscopic surgery, but trainees are selected by academic prowess rather than surgical aptitude. SUBJECTS AND METHODS: The MIST-VR system was used to test 122 volunteers in three groups, i.e. 39 consultant urologists, 46 urological trainees and 37 controls (not surgeons). The demographic data recorded for each group included age, sex, eyesight, handedness, and endoscopic and laparoscopic experience. Volunteers performed a repetitive series of three tasks using the system. Their performance was measured in terms of time, errors and economy of movement, as well as the duration and accuracy of diathermy in Task 3. RESULTS: The consultants were significantly older than the trainees and controls (both P<0.001) and had more endoscopic experience (P=0.005). In Task 1, the trainees made significantly fewer errors (P=0.045) and had a greater economy of movement (P=0.03) than the controls. In Task 2 the trainees performed the task more rapidly than the consultants (P=0.04) and controls (P=0.02). Trainees were more economical in movement than were consultants (P=0.031) and controls (P=0.046). In the more complex Task 3, trainees outperformed consultants in terms of errors (P=0.03), economy of movement (P=0.046), total diathermy time (P=0.005) and diathermy error (P=0.03). Controls performed similarly to the consultants. Although there was a trend towards better performance by trainees over controls, this was only significant for time (P=0.04) and total diathermy time (P=0.011). A few participants had results that were >2 SD above the mean and several people could not complete Task 3. CONCLUSIONS: Urologists do not differ from the general population in terms of innate spatial ability in this setting. There are several people who may have a defect in spatial awareness but the incidence was the same in each group. Urological trainees outperformed consultants in these tasks; the reasons for this are unclear. The MIST-VR system is of no help in aptitude testing for urological trainees, although it may have a role in teaching laparoscopic surgery. Testing other psychometric components may be more important for acquiring surgical skills than innate spatial-awareness skills. Further studies are required to investigate this possibility.

Weight management practices among primary care providers.

This pilot study examined how primary care providers manage patients with weight problems, an important component of primary care. A convenience sample of 17 nurse practitioners and 15 physicians were surveyed about assessments and interventions used in practice for weight management along with perceived barriers to providing effective weight management. Practice patterns between gender, profession and practice setting of the nurse practitioners were compared.

New directions for the study of overweight.

In this issue, three authors contribute to our knowledge of triggers or cues to weight-related behavior. Two of these authors focus on the effect of emotion on eating behavior. Popkess-Vawter, Wendel, Schmoll, and O'Connell (1998, in this issue) explicate reversal theory as a way to account for feelings and stress that trigger weight cyclers to overeat. Timmerman (1998, in this issue), in a study of nonpurge binge eaters, reports the relationship between caloric intake patterns and binge eating. Both researchers have added to our knowledge about triggers to eating behavior. Finally, Brink and Ferguson (1998), in their study of male and female successful dieters, add to the limited knowledge concerning triggers to weight loss. They describe reasons for deciding to lose weight among a population of successful underweight, normal weight, and obese dieters. Three authors contribute to the new weight research thrust of prevention. Two of the authors report the results of intervention studies. Reifsnider (1998, in this issue), in the only article on children, presents a follow-up study of a family-focused, community-based nursing intervention for growth-deficient, low-income Euro-American and Mexican American preschool children. Her work is an example of the context- and lifestyle-sensitive prevention-focused studies needed in weight research. Ciliska (1998, in this issue) reports findings from a randomized trial of a psycho-educational intervention with obese healthy women aimed at increasing self-esteem and decreasing restrained eating patterns. Her work follows some new thinking in the area of weight control that recognizes the dangers of chronic dieting and proposes a focus on self-acceptance, better nutrition, regular physical activity, and the prevention of further weight gain triggered by chronic dieting (Brownell & Cohen, 1995). Walker (1998, in this issue), the third author, in a multiethnic study of new mothers, explores the concept of weight-related distress and associations of anthropometric and psychosocial variables with feelings about weight. Her work adds to our understanding about critical periods and risks for weight gain. Allan (1998, in this issue), in a study of African American, Euro-American, and Mexican American women, reports women's explanatory models of overweight and the congruence of these models with professional models and recommendations for treatment for overweight. Her research contributes needed understandings of how high-risk populations view overweight, how participants' lifestyles and situations influence their ideas about weight, and how these perspectives influence efforts to control weight. Nursing needs to continue to refine and rethink what constitutes research on weight. This special issue offers some examples of scholars attempting to trailblaze new directions in nursing weight research. One thrust has been the significant attention on weight as a focus of investigation and not just as one of several health behaviors. A second and equally compelling area of inquiry has been the explicit attention directed to studying people of color, especially women, within the social context of their lives. Because ethnicity, social status, and gender are inextricably intertwined with health, one challenge is to try to understand weight issues through an ethnic, gender, and social status lens. Researchers who embrace this paradigm refuse to look at weight as a homogeneous condition but focus their attention instead on specific subgroups in the population without making middle-class Euro-Americans the norm. The number of researchers who are examining connections between ethnicity and social status and weight is growing. The complexity of weight-health promotion requires that we not only boldly examine weight in relationship to the individual in context but also explicate the macroenvironmental influences on weight. More needs to be done to translate findings from this body of research into better models

Explanatory models of overweight among African American, Euro-American, and Mexican American women.

Ethnographic interviewing methods were used to explore women's explanatory models (EMs) of overweight and the congruence of these models with professional models and professionally recommended treatments for overweight. Through community-based snowball and theoretical sampling, 40 African American, 40 Euro-American, and 40 Mexican American women of varying social status and weight participated in multiple ethnographic interviews, which were subsequently interpreted using domain analysis and constant comparison. Study participants' EMs of overweight ranged from simple to complex, were generally similar across the three study groups, and only partially congruent with professional EMs of obesity. Major differences in EMs between the study groups were found in the dimensions of etiologies and consequences of overweight. There was partial congruence between participants' EMs and professionally recommended treatments for overweight.

Striving for quality in advanced practice nursing education.

The issue of establishing and maintaining high-quality advanced practice educational programs, practice competencies, and certification criteria is currently the focus of much debate and discussion within nursing. This article focuses on the issue of accreditation for advanced practice nursing educational programs in four areas: (1) history of accreditation in nursing education; (2) accreditation of educational programs for clinical nurse specialists, nurse midwives, and nurse anesthetists; (3) accreditation of programs for nurse practitioners; and (4) current and future educational issues and challenges. To participate in shaping the changes occurring in the current health delivery system, the nursing profession and advanced practice nursing educators must present a strong, visionary, and collaborative voice concerning quality educational programs.

Weight loss methods used by African American and Euro-American women.

In this naturalistic study employing intensive interviews and anthropometric measures, an educationally and economically diverse community-based sample of 40 African American and 40 Euro-American women described their lifetime experiences with weight management. Twenty types of weight loss methods were identified and grouped into one of three categories: lifestyle work, head work, and professional services. The most frequently used weight loss methods were from the lifestyle work category, with the leading methods identified as exercise on own and reduce high calorie and/or increase low calorie foods. African Americans and Euro-Americans overwhelmingly used similar weight loss methods, with the only significant difference occurring in the more frequent use of commercial diet products among the African American group. Methods from the head work category were used significantly more often by women with higher social status, while heavier women more frequently sought professional services to lose weight than thinner women. The Euro-American women engaged in weight loss methods for significantly longer periods of time and were found to weigh significantly less than the African American women. These findings suggest that the shorter duration of weight loss attempts may be a major factor contributing to the larger body size in African American women.

Exploring the use of explanatory models in nursing research and practice.

PURPOSE: To address the lack of information in nursing for delivering culturally appropriate care and provide a framework for nurses to incorporate diverse beliefs and health needs into research and practice. People interpret and react to health and illness events within a cultural system. However, the nursing literature contains little about how to elicit cultural beliefs. ORGANIZING FRAMEWORK: Use of Kleinman's (1980) concept of explanatory models (EMs) is explored first, by describing the concept as it was developed by Kleinman, and second, by illustrating how it was used in three research studies conducted between 1990 and 1994. METHOD: Individual in-depth interviews were conducted with community-based convenience samples. Data were analyzed using content analysis. Explanatory models were explored with health people following illness, and with people having a condition with potential health risks, to illustrate their usefulness in nursing research and practice. CONCLUSIONS: The findings provide a beginning understanding of the complex linkages between beliefs and actions and demonstrate the versatility and usefulness of EMs for nursing research and practice. Assessing models offers one means for researchers and clinicians to explore health beliefs and the linkages between beliefs and behaviors.

Dispersal as a regional process affecting the local dynamics of marine and stream benthic invertebrates.

Recent work has shown that benthic invertebrate assemblages may be influenced in an ongoing fashion by dispersal. Water-column movements of meiofauna, juvenile insects and marine postlarvae are common and can act to alter greatly local dynamics such as predator-prey and competitive interactions in marine and stream ecosystems. These findings are important because past research on the role of dispersal in invertebrate dynamics has focused almost exclusively on how planktonic larval supply influences the establishment and maintenance of local assemblages, on the colonization of newly opened sites, or on the settlement success of new recruits. The emerging framework is that dispersal needs to be viewed as a regional process that may routinely influence local benthic dynamics, because fauna can move to and from water-column dispersal 'pools' and may do so at frequent intervals.

Combination and monotherapy with zidovudine and zalcitabine in patients with advanced HIV disease. The NIAID AIDS Clinical Trials Group.

OBJECTIVE: To compare the safety and efficacy of continuing zidovudine therapy with that of zalcitabine alone or zalcitabine and zidovudine used together. DESIGN: A randomized, double-blind, controlled trial. SETTING: AIDS Clinical Trials units and National Hemophilia Foundation sites. PATIENTS: 1001 patients with symptomatic human immunodeficiency (HIV) disease and 300 or fewer CD4 cells/mm3 or asymptomatic HIV disease and 200 or fewer CD4 cells/mm3 who had tolerated zidovudine therapy for 6 months or more. INTERVENTION: Patients were randomly assigned to receive zidovudine, 600 mg/d; zalcitabine, 2.25 mg/d; or zidovudine, 600 mg/d, and zalcitabine, 2.25 mg/d. MEASUREMENTS: The primary end point was time to disease progression or death. RESULTS: The median follow-up time was 17.7 months. The estimated 12-month event-free rates were 70%, 67%, and 73%, respectively, for the zidovudine, zalcitabine, and combination groups (P = 0.26). A trend analysis showed significantly lower progression rates for combination therapy compared with zidovudine therapy as the pretreatment CD4 cell count increased (P = 0.027). For patients with 150 or more CD4 cells/mm3, those receiving combination therapy were less likely to have disease progression or to die than were those receiving zidovudine (relative risk, 0.51; 95% CI, 0.28 to 0.93; P = 0.029). We observed no difference between the zalcitabine and zidovudine groups (relative risk, 0.74; CI, 0.40 to 1.36; P = 0.33). For patients with 50 to 150 CD4 cells/mm3 or fewer than 50 CD4 cells/mm3, we found no differences among the treatment groups (P = 0.69 and P = 0.57, respectively). Severe toxic effects occurred less frequently among patients with 150 or more CD4 cells/mm3. CONCLUSIONS: We found no overall benefits of zalcitabine used alone or with zidovudine. However, a trend analysis suggested a better outcome for combination therapy compared with zidovudine as the pretreatment CD4 cell count increased.

A biomedical and feminist perspective on women's experiences with weight management.

Weight concerns and dieting have become so normative for U.S. women that weight is the lens through which experience is viewed. The obsession with weight and dieting among women is considered by feminists to be one result of the oppression by women resulting from questionable weight standards and weight control programs that foster a view of overweight as a sign of addiction and lack of control. Feminist critique is used to deconstruct both the literature related to weight standards and health and the research on weight loss/weight management. Feminist and ethnographic methods are used to describe successful and unsuccessful experiences with weight management of 20 Euro-American women who had participated in a 1985 weight study and agreed to be reinterviewed. Success at weight management was examined from a biomedical perspective using Body Mass Index (BMI) norms and from a feminist perspective using participants' subjective definitions of success. Based upon BMI, only 8 members of the study group were defined as successful, whereas based upon the women's perspectives, 11 members were successful. Participants' definitions of successful weight management were divergent from biomedical definitions and could be categorized into three perspectives: biomedical, reframed normal weight, and holistic. Women who ascribed to the biomedical definition of success embodied the cultural ideal of thinness by adhering to an underweight weight norm. Participants using the reframed normal weight definition of success rejected biomedical weight norms and created their own weight norms. The holistic perspective on success involved the use of a broader, health-focused definition of successful weight management and offers some directions for revising current health promotion care relative to weight.