Increasing springtime ozone mixing ratios in the free troposphere over western North America.

In the lowermost layer of the atmosphere-the troposphere-ozone is an important source of the hydroxyl radical, an oxidant that breaks down most pollutants and some greenhouse gases. High concentrations of tropospheric ozone are toxic, however, and have a detrimental effect on human health and ecosystem productivity. Moreover, tropospheric ozone itself acts as an effective greenhouse gas. Much of the present tropospheric ozone burden is a consequence of anthropogenic emissions of ozone precursors resulting in widespread increases in ozone concentrations since the late 1800s. At present, east Asia has the fastest-growing ozone precursor emissions. Much of the springtime east Asian pollution is exported eastwards towards western North America. Despite evidence that the exported Asian pollution produces ozone, no previous study has found a significant increase in free tropospheric ozone concentrations above the western USA since measurements began in the late 1970s. Here we compile springtime ozone measurements from many different platforms across western North America. We show a strong increase in springtime ozone mixing ratios during 1995-2008 and we have some additional evidence that a similar rate of increase in ozone mixing ratio has occurred since 1984. We find that the rate of increase in ozone mixing ratio is greatest when measurements are more heavily influenced by direct transport from Asia. Our result agrees with previous modelling studies, which indicate that global ozone concentrations should be increasing during the early part of the twenty-first century as a result of increasing precursor emissions, especially at northern mid-latitudes, with western North America being particularly sensitive to rising Asian emissions. We suggest that the observed increase in springtime background ozone mixing ratio may hinder the USA's compliance with its ozone air quality standard.

Eruptions of the st. Augustine volcano: airborne measurements and observations.

Airborne measurements of the effluents from the St. Augustine volcano obtained during a 10-day period of activity showed that aerosol was ejected at the rate of about 10(5) kilograms per second during brief eruptions (3 to 8 minutes). Steadier emissions contained much more water vapor and gaseous sulfur but less aerosol mass. A nuée ardente (glowing avalanche) produced by one eruption reached a maximum average speed of about 50 meters per second.

MR in neurofibromatosis of the larynx.

We report the MR results of four patients with plexiform neurofibromas of the larynx. Three had irregular margins and were circumferential around the airway. The distinction between regularly and irregularly shaped neurofibromas may have implications for symptom onset.

Personal, interpersonal, and organizational influences on student satisfaction with clinical education.

BACKGROUND AND PURPOSE: Understanding the factors that contribute to student satisfaction may lead to improved education in physical therapy. This study tested the extent to which variables in the personal, interpersonal, and organizational domains influence satisfaction with clinical experiences. SUBJECTS: Physical therapist students (N = 113) in 2 phases of their clinical experiences at one private school participated. METHODS: A nonexperimental design tested 3 models for predicting overall satisfaction. Students completed 3 surveys and weekly logs during 8-week-long clinical experiences. RESULTS: The survey return rate was 96%. Overall satisfaction with the clinical experience was predicted by life satisfaction, gender, off-site events, on-site events, interaction between negative events and gender, instructor teaching skills, interaction between education phase and gender, variety, and use of selected orientation methods. CONCLUSION AND DISCUSSION: Overall satisfaction is predicted by variables in all 3 domains. Overall satisfaction was best explained by factors in the interpersonal domain and student gender. Causal research is needed to confirm whether satisfaction can be improved and whether the results apply to other students at other schools. The relationships among satisfaction, performance, later job satisfaction, and career commitment need to be explored further.

Papillary adenocarcinoma in ectopic thyroid.

A single case of papillary adenocarcinoma of median ectopic thyroid is presented. There have been 96 other similar cases reported in the English literature. Since the tumor rarely involves the cervical lymphatics or thyroid gland in the absence of a palpable mass, local excision with the Sistrunk procedure is the recommended therapy. Suppression doses of thyroid hormone may be of benefit.

Study of humidification potential of a heat and moisture exchanger in tracheotomized dogs.

Though a heat and moisture exchanger (HME) has been used in clinical practice following a tracheotomy on a limited basis, no work has been done to document the humidification potential of an HME in this situation. Eighteen dogs underwent tracheotomy and were killed at either 1 day (nine dogs) or 10 days (nine dogs) postoperatively. Following the tracheotomy, the animals were divided into three groups according to the type of humidification received: ambient conditions, warm mist, or HME. The tracheal mucosa was studied for histologic changes in the cilia, the epithelium, submucosal reaction, and mucus production at the level of the carina. The results were significant (p = .02) for the interaction of the experimental type and method of treatment in their effect on the histologic changes noted at the carina. The study supports the use of an HME as an alternative for long-term humidification in a patient with a tracheotomy.

Non-Hodgkin's lymphomas of the nose and paranasal sinuses in the pediatric population.

Paranasal and nasal neoplasms often elude early diagnosis in the pediatric population. This report examines 3 cases of nasal and paranasal sinus lymphomas out of 29 lymphomas and lymphoproliferative disorders seen from 1983 to 1990. Diagnostic delays are common. The development of orbital signs and symptoms often leads to diagnosis. Computed tomography and magnetic resonance imaging are important in delineating the extent of disease and allow appropriate staging. Transnasal biopsy yields the definitive diagnosis, with low associated morbidity. Aggressive chemotherapy and irradiation prolongs survival; with this regimen all of our patients have remained alive, although 1 has residual disease. B-cell lymphomas are more common than T-cell varieties in children. One patient demonstrated B-cell immunodeficiency and preleukemia prior to developing primary paranasal sinus non-Hodgkin's lymphoma; this case reiterates the systemic nature of lymphoma, Key differences between children and adults in the manifestations of nasal and sinus lymphomas are emphasized.

Extraluminal esophageal coin erosion in children. Case report and review.

Coins are often reported as the most commonly ingested foreign body (FB) in children. They are felt to be benign FBs since they usually pass through the gastrointestinal tract without incident. However, when these objects become impacted within the esophageal lumen, they can perforate the esophagus and migrate extraluminally. Symptoms of the perforation itself are frequently absent, but the potential vascular and suppurative complications may be devastating. We present the 10th reported case of complete extraluminal migration of an esophageal coin, and the only case which was treated without an open surgical procedure. Because of the potential complications, we recommend aggressive surgical intervention as soon as the diagnosis is made.

Sleep apnea in patients receiving growth hormone.

Among 145 patients treated with recombinant human growth hormone (GH), four developed sleep apnea (two obstructive, two mixed) associated with tonsillar and adenoidal hypertrophy in three. These four patients had no local risk factors predisposing to upper airway obstruction (i.e., frequent pharyngitis or sinusitis). Clinical and/or polysomnographic features of sleep apnea improved following cessation of GH therapy in one patient, and following tonsillectomy and adenoidectomy in all patients. The present observations indicate that, albeit rarely, obstructive and/or central sleep apnea may occur in children treated with GH. Polysomnography should be considered if symptoms of snoring, interrupted sleep, daytime somnolence-particularly if associated with tonsillar hypertrophy-appear in children during GH therapy.

Selecting new board members and officers.

A hospital's chief executive officer has a responsibility to work with the governing board to ensure effective grooming, recruitment, replacement, and performance of board members and officers.

Extensor digitorum brevis manus: a case report review.

A detailed description of bilateral extensor digitorum brevis manus (EDBM) present in a female cadaver is presented. The need for clinical recognition is emphasized. Prevalence, morphological variability and theories of ontogeny are reviewed. Clinical significance and possible function are discussed. Since misdiagnosis may result from the anatomical variability and lack of clinical awareness, the need for further study is emphasized.

Sleep abnormalities in patients with severe cerebral palsy.

The all-night polysomnographic findings of nine patients with spastic quadriparesis (mean age 36.7 months) were analysed retrospectively and compared with those of nine age-matched controls (mean age 37.4 months). The cerebral palsy group had significantly more respiratory disturbances per hour of sleep, with five of nine being diagnosed as having obstructive sleep apnea. They also had fewer changes in body position during the night. Interictal epileptiform discharges averaged 23.3 per cent of the total arousals in the cerebral palsy group. Obstructive apnea, decreased ability to change body position, and interictal epileptiform discharges are prevalent in the sleep of patients with severe cerebral palsy, and contribute towards its disruption.

The development and evaluation of a small ready-reference library collection for a rural practice: a case study.

A demonstration core collection of twenty-four ready-reference sources and five journals was selected cooperatively by a solo practitioner in rural Menifee County, Kentucky, and the University of Kentucky Medical Center Library Field Librarian to fit the ready-reference and current awareness information needs of a primary care solo rural practice in eastern Kentucky. The collection selections were systematically assessed by the physician to determine their utility in filling the practitioner's information needs with regard to his particular situation in terms of medical experience and level of training, available library and educational resources, and the type of health problems seen in his practice. This assessment showed that the Rural Demonstration Library Collection completely filled the information needs of the physician 66% of the time materials were consulted and filled his immediate information needs either completely or partially 82% of the time the collection was searched. This demonstration has shown that, under a specific set of circumstances, a librarian and a solo rural practitioner can effectively work together in identifying health sciences materials which fit the information needs of a solo rural practitioner. It suggests that cooperation between a librarian and a physician is important in meeting information needs.