Collaboration Structure, Communication Media, and Problems in Scientific Work Teams

This article reviews the structural characteristics of work organizations that are likely to increase collaboration problems and tests the relationships between collaboration structure and problems using data from a survey of scientists in four fields (experimental biology, mathematics, physics, and sociology). Two groups of problems are identified: problems of coordination and misunderstandings and problems of cultural differences and information security. Greater coordination problems are associated with size, distance, interdependence, and scientific competition. Problems of culture and security are associated with size, distance, scientific competition, and commercialization. Email use is associated with reporting fewer coordination problems, but not fewer problems of culture and security, while neither phone use nor face-to-face meetings significantly reduces problems. We conclude with a discussion of the implications of these findings for designers of collaboration technologies and researchers involved in scientific collaborations.     

QuickBird and Hyperion data analysis of an invasive plant species in the Galapagos Islands of Ecuador: Implications for control and land use management

In the Galapagos Islands of Ecuador, one of the greatest threats to the terrestrial ecosystem is the increasing number and areal extent of invasive species. Increased human presence on the islands has hastened the introduction of plant and animal species that threaten the native and endemic flora and fauna. Considerable research on invasive species in the Galapagos Islands has been conducted by the Charles Darwin Foundation. We complement that work through a spatially- and spectrally-explicit satellite assessment of an important invasive plant species (Psidium guajava — guava) on Isabela Island that integrates diverse remote sensing systems, data types, spatial and spectral resolutions, and analytical and image processing approaches. QuickBird and Hyperion satellite data are processed to characterize the areal extent and spatial structure of guava through the following approaches: (1) QuickBird data are classified through a traditional pixel-based approach (i.e., an unsupervised classification approach using the ISODATA algorithm), as well as an Object-Based Image Analysis (OBIA) approach; (2) multiple approaches for spectral “unmixing” of the Hyperion hyper-spectral data are assessed to construct spectral end-members from QuickBird data using linear and non-linear mixture modeling approaches; and (3) landscape pattern metrics are calculated and compared for the pixel-based, object-based, and spectral unmixing approaches. The spectral–spatial characteristics of guava are interpreted relative to management strategies for the control of guava and the restoration of natural ecosystems in the Galapagos National Park.     

A survey of Legionella pneumophila in water in 12 Canadian cities

A survey of 12 cities across Canada was conducted in order to determine the prevalence of Legionella species in potable water and cooling tower water within buildings. Legionellae were detected in 11.9% of the samples overall: 6.7% from potable water sources and 28.9% from cooling tower water. The maximum concentration of the organism was 45,000 l⁻¹ in one shower-water sample by culture methods. A significant difference in the isolation rate of Legionella pneumophila among cities was observed. The organism was isolated from waters at a temperature of 15–41°C and was most frequently isolated in the 20–29°C range. The concentration of free and total available chlorine in the water was not associated with legionellae recovery except that the organisms were never recovered when the free available chlorine residual exceeded 7.5 mg l⁻¹. Although L. pneumophila were in low concentrations or absent in most samples, the isolated organisms were usually serogroups 1 or 6, the same serogroups that are most often implicated in legionellosis cases in Canada.     

Caspases: intracellular signaling by proteolysis

The standard working assumption of careful CRT imaging is that each pixel is imaged independently, through a point nonlinearity (the monitor's gamma function, relating screen luminance to input voltage), and then blurred by the point-spread function of the beam spot on the phosphor. Unfortunately most monitors have inadequate video bandwidth, DC restoration, and high-voltage regulation to live up to this ideal model. Two tests are recommended for assessing a CRT's deviation from the pixel-independence model.     

Increased restenosis in diabetes mellitus after coronary interventions is due to exaggerated intimal hyperplasia. A serial intravascular ultrasound study

Hepatic hydrothorax is a rare complication of portal hypertension. Conservative therapy may be successful but refractory hepatic hydrothorax is not uncommon. Management of refractory hydrothorax is usually ineffective and can result in a worsened clinical status. Transjugular intrahepatic portosystemic shunts (TIPS) lower portal pressure and have been used in the treatment of refractory ascites. The aim of this study was to determine the efficacy of TIPS in the treatment of symptomatic refractory hepatic hydrothorax. A TIPS was placed in 24 consecutive cirrhotic patients with symptomatic refractory hepatic hydrothorax. Five patients (20.8%) were Child's/Pugh class B and 19 (79.2%) were class C. All had undergone multiple thoracenteses and were hypoalbuminemic. Mean follow-up was 7.2 months (range, 0.25-49 months). Fourteen (58.3%) of 24 patients had complete relief of symptoms after shunt placement and did not require further thoracentesis. Five (20.8%) additional patients required fewer thoracenteses. Five (20.8%) patients developed worsening liver function and died within 45 days. In eight (66.7%) of 12 patients with > or = 60 days of follow-up, the serum albumin increased by a mean of 1.2 g/dL (range, 0.1-2.2 g/dL). The Child's-Pugh score improved in 7 (58.3%) of these 12 patients and two patients improved from class C to class A. These two patients no longer require liver transplantation. This study shows that TIPS can be effective in the management of symptomatic, refractory hepatic hydrothorax. Clinical and laboratory improvement may be seen and liver transplantation may become unnecessary.     

Pharmacokinetics of nicotine carbomer enemas: a new treatment modality for ulcerative colitis

BACKGROUND: Ulcerative colitis is largely a disease of nonsmokers, and transdermal nicotine is of therapeutic value in the active disease. Because side effects are common, we developed a topical enema formulation of nicotine. OBJECTIVE: To study the pharmacokinetics of nicotine complexed with a polyacrylic carbomer and administered by enema to eight healthy volunteers and to eight patients with active ulcerative colitis, verified sigmoidoscopically. PATIENTS AND METHODS: All 16 subjects were nonsmokers. The mean age for normal subjects was 33 years; the mean for patients with ulcerative colitis was 60 years. Median stool frequency for patients with ulcerative colitis was four daily. Patients were taking 5-amino salicylic acid compounds and five were taking oral prednisolone (median dose, 12 mg daily). Nicotine, 6 mg, complexed with carbomer 974P, 400 mg, was administered in a 100 ml enema after an overnight fast, with serial blood measurements taken over 8 hours. Serum nicotine and cotinine were measured by gas liquid chromatography. Area under the concentration-time curves were calculated by the trapezoidal method, and the terminal elimination half-life was derived by extrapolation of the log-linear terminal phase. RESULTS: With the exception of nicotine time to reach peak concentration, which was longer in patients (median of 60 minutes compared with 45 minutes; p < 0.005), other comparisons between normal subjects and patients showed no statistically significant difference, although there was considerable inter-subject variation. Maximum concentration of nicotine, 8.1 +/- 3.5 ng/ml, in the 16 subjects occurred after a median of 60 minutes (range, 30 to 180 minutes); maximum cotinine concentrations of 60.4 +/- 11.5 ng/ml occurred after 4 hours. Side effects in five subjects were mild (four subjects) or moderate (one subject) and included lightheadedness, nausea, and headache; these five subjects were female lifelong nonsmokers of low body weight. CONCLUSION: Because most of the active ingredient of nicotine is converted to continine on the first pass through the liver, substantial concentrations can be achieved at the site of disease with only modest rises in serum nicotine, which are responsible for side effects; cotinine has low pharmacologic activity. Topical administration of nicotine may be useful treatment for distal ulcerative colitis.     

Single-laser approach for fluorescence guidance of excimer laser angioplasty at 308 nm: evaluation in vitro and during coronary angioplasty

BACKGROUND AND OBJECTIVE: Spectroscopic guidance of laser angioplasty has been attempted using a diagnostic He-Cd laser in addition to the therapeutic laser system. This study evaluated a single-laser approach for simultaneous ablation and fluorescence excitation. STUDY DESIGN/MATERIALS AND METHODS: A spectroscopy system was coupled to a clinical XeCl excimer laser. Ablation of 162 human aortic samples in saline and blood with 45 mJ/mm2 per pulse yielded 676 fluorescence spectra validated histologically. The same equipment was used in 16 patients for angioplasty of 18 coronary stenoses applying 500 to 1,725 pulses with 45 to 60 mJ/mm2 under saline flushing. A total of 783 spectra were recorded and validated by intracoronary ultrasound (categories: atheroma, fibrous plaque, calcified lesion). RESULTS: In vitro, 5 types of spectra could be differentiated: (1) atheroma, (2) fibrous plaque, (3) calcified lesion in saline, (4) media, and (5) calcified lesion in blood. Discriminant analysis prospectively classified 576 validation spectra with the following sensitivity and specificity for each type: (1) 83.5 and 97.1%, (2) 85.7 and 96.8% (3) 100 and 98.5%, (4) 98.1 and 99.3%, (5) 98.9 and 100%, respectively. In vivo type 1, 2, 3, and 5 spectra were also observed, but not the media spectrum. The predominant sonographic category also prevailed in spectroscopy. Calcified lesions yielded type 3 and 5 as well as mixed spectra. CONCLUSIONS: Using an excimer laser for angioplasty allows combining ablation and fluorescence excitation without a diagnostic laser. Principal types of atherosclerotic lesions and the media can be differentiated spectroscopically with this approach.     

Diathermy tonsillectomy: comparisons of morbidity following bipolar and monopolar microdissection needle excision

Tonsillectomy is frequently associated with a considerable post-operative morbidity. In some cases reactionary or secondary haemorrhage occurs and all patients suffer a degree of post-operative pain. The use of bipolar diathermy excision has become popular because it reduces intra-operative blood loss, but all diathermy inevitably produces a degree of damage to adjacent normal soft tissues. In turn this inadvertent injury must act to increase the post-operative pain. Monopolar dissection using a fine tungsten diathermy needle (the Colorado needle) allows sharp dissection at low power levels and in previous studies has been shown to produce a reduction in collateral tissue damage. In this prospective study the morbidity associated with tonsillectomy using this needle was compared to that following a standard bipolar dissection. Using the monopolar needle produced no enhanced risk of reactionary or secondary haemorrhage while causing significantly less post-operative pain and a reduction in eschar. We believe that excision using this needle preserves the advantages associated with bipolar dissection while reducing local soft tissue damage.