Context. Classical Cepheids are excellent tracers of intermediate- mass stars, since their distances can be estimated with very high accuracy. In particular, they can be adopted to trace the chemical ...evolution of the Galactic disk. Aims. Homogeneous iron abundance measurements for 33 Galactic Cepheids located in the outer disk together with accurate distance determinations based on near-infrared photometry are adopted to constrain the Galactic iron gradient beyond 10 kpc. Methods. Iron abundances were determined using high resolution Cepheid spectra collected with three different observational instruments: ESPaDOnS/CFHT, Narval-TBL and FEROS-2.2m ESO/MPG telescope. Cepheid distances were estimated using near-infrared (J, H, K-band) period-luminosity relations and data from SAAO and the 2MASS catalog. Results. The least squares solution over the entire data set indicates that the iron gradient in the Galactic disk presents a slope of-0.052\pm0.003 dex kpc super(-1) in the 5-17 kpc range. However, the change of the iron abundance across the disk seems to be better described by a linear regime inside the solar circle and a flattening of the gradient toward the outer disk (beyond 10 kpc). In the latter region the iron gradient presents a shallower slope, i.e.-0.012\pm0.014 dex kpc super(-1). In the outer disk (10-12 kpc) we also found that Cepheids present an increase in the spread in iron abundance. Current evidence indicates that the spread in metallicity depends on the Galactocentric longitude. Finally, current data do not support the hypothesis of a discontinuity in the iron gradient at Galactocentric distances of 10-12 kpc. Conclusions. The occurrence of a spread in iron abundance as a function of the Galactocentric longitude indicates that linear radial gradients should be cautiously treated to constrain the chemical evolution across the disk.
There are concerns that large-scale stand mortality due to mountain pine beetle (MPB) could greatly reduce natural regeneration of serotinous Rocky Mountain (RM) lodgepole pine (
Pinus contorta
var.
...latifolia
) because the closed cones are held in place without the fire cue for cone opening. We selected 20 stands (five stands each of live control, 3 years since MPB 3-yr-MPB, 6 years since MPB 6-yr-MPB, and 9 years since MPB 9-yr-MPB mortality) in north central British Columbia, Canada. The goal was to determine partial loss of serotiny due to fall of crown-stored cones via breakage of branches and in situ opening of canopy cones throughout the 2008 and 2009 growing seasons. We also quantified seed release by the opening of forest-floor cones, loss of seed from rodent predation, and cone burial. Trees killed by MPB three years earlier dropped ∼∼3.5 times more cones via branch breakage compared to live stands. After six years, MPB-killed stands had released 45%% of their canopy seed bank through cone opening, cone fall due to breakage, and squirrel predation. Further losses of canopy seed banks are expected with time since we found 9-yr-MPB stands had 38%% more open canopy cones. This was countered by the development of a modest forest-floor seed bank (6%% of the original canopy seed bank) from burial of cones; this seed bank may be ecologically important if a fire or anthropogenic disturbance reexposes these cones. If adequate levels of regeneration are to occur, disturbances to create seedbeds must occur shortly after tree mortality, before the seed banks are lost. Our findings also suggest that the sustained seed rain (over at least nine years) after MPB outbreak may be beneficial for population growth of ground-foraging vertebrates. Our study adds insight to the seed ecology of serotinous pines under a potentially continental-wide insect outbreak, threatening vast forests adapted to regeneration after fire.
Decision Aids for Tunneling Einstein, Herbert H.; Indermitte, Claude; Sinfield, Joseph ...
Transportation research record,
1999, Letnik:
1656, Številka:
1
Journal Article, Conference Proceeding
Recenzirano
The decision aids for tunneling (DAT) are a computer-based tool with which tunnel construction cost and time as well as required and produced resources can be computed. The DAT work with standard ...information such as geologic/geotechnical, structural, and material characteristics as well as construction performance. The two major components of the DAT, the “description of geology” and “construction simulation and construction management” are reviewed followed by descriptions of major applications of the DAT. Specifically, this involves application in the projects of two new transalpine rail tunnels in Switzerland (Gotthard, 57 km; Lötschberg, 36 km), investigation of different alternatives for a Metro project, and, finally, use of the DAT for assessing the effect of new tunneling technology on cost and time of construction.
Numerous reviews of adenocarcinoma arising in Barrett's esophagus have been reported, but detailed pathologic findings or survival analysis have rarely been provided. This retrospective study ...analyzed 67 patients (mean age, 64 years; male-to-female ratio, 10:1) with an adenocarcinoma arising in Barrett's esophagus treated by surgical resection. Prevalence of smokers was 63%, alcohol users, 45%, and patients with hiatal hernia, 73%. Five patients had another synchronous cancer, and seven patients, previous esophageal surgery. Forty percent of the tumors were well differentiated, 31% moderately differentiated, 15% poorly differentiated, 7% mucinous, and 6% composed of signet-ring cells. Depth of invasion in the esophageal wall was limited to mucosa in 13% of cases and submucosa in 18%. Invasive adenocarcinomas extended to the muscular layer in 12% of cases, to adventitia in 33%, and to periesophageal tissue in 24%. Vascular and perineural neoplastic invasion was present in 67 and 38% of cases. Regional lymph node involvement and distant metastases were found in 51 and 9% of cases. Overall, 1-, 2-, and 5-year survival rates were 63, 41, and 32%, respectively. Five-year survival rate was significantly better for patients with superficial cancer limited to mucosa or submucosa (82 vs. 12%) or without regional lymph node involvement (59 vs. 10%). Tumor differentiation, vascular and perineural invasion, extranodal spread, distant metastases, and resection margins status also had a significant prognostic value on univariate analysis. In a multivariate Cox regression analysis for overall survival, depth of invasion in the esophageal wall and regional lymph node involvement were independent prognostic factors. Careful pathologic staging is of value in determining the prognosis of patients with adenocarcinoma arising in Barrett's esophagus.
This paper analyses some data on the eating habits and weight variations in the student population of the University of Geneva, Switzerland. Of the 11,800 questionnaires sent out, 4200 were returned ...within 2 months. Among those students who responded, 52.1% of the women and 37.4% of the men desire a weight change. For 80.9% of the respondents, a weight loss is desirable. At least one method of weight control is used by 9.8% of the men and by 22.9% of the women. Previous use of methods of weight control were indicated by 16.7% of the men and 49.2% of the women. The prevalence of bulimia can be estimated at 4% among women and 0.7% among men.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
There is no consensus regarding which exercise test to use to evaluate the functional impact of bronchodilators in patients with chronic obstructive pulmonary disease.
Bronchodilator-induced changes ...in endurance time were evaluated during cycling and walking in 17 patients with chronic obstructive pulmonary disease who completed two cycle endurance tests and two endurance shuttle walks at 80% of peak capacity. Each endurance test was preceded by the nebulization of a placebo or 500 microg of ipratropium bromide using a randomized, double-blind, crossover design. Quadriceps twitch force was measured with magnetic stimulation of the femoral nerve before and after each endurance test.
Cycling endurance time did not improve significantly after bronchodilation despite a significant increase in FEV1 (delta endurance time ipratropium bromide - placebo: 51 +/- 255 s, p = 0.42). A similar change in FEV1 was associated with a significant improvement in walking endurance time (delta endurance time ipratropium bromide - placebo: 164 +/- 177 s, p < 0.01). A 22 +/- 17% fall in quadriceps twitch force was observed after cycling, whereas no significant change was seen after walking.
The endurance shuttle walk is a sensitive test to detect changes in exercise tolerance after bronchodilation. Differences in the occurrence of quadriceps muscle fatigue may explain, in part, the different responsiveness to change between cycling and walking.
Background. Necrotizing pneumonia due to Panton-Valentine leukocidin–producing strains of Staphylococcus aureus is associated with a high mortality rate. We sought factors associated with vital ...outcome in 50 cases occurring from 1986 through 2005. Methods. We compared the clinical and biological characteristics of 50 patients according to their vital outcome and examined the characteristics of the corresponding S. aureus isolates. Results. The overall mortality rate was 56%, and the median survival time was 10 days. All of the deaths were attributed to S. aureus infection and were secondary to refractory shock and/or respiratory failure. Fatal outcome was associated with classical severity factors, such as the need for mechanical ventilation or inotrope support, and with onset of the acute respiratory distress syndrome. Airway bleeding was strongly associated with fatal outcome (P = .002). Patients who had focal staphylococcal infection before the onset of pneumonia had a significantly lower mortality rate (P = .002). The main biological feature associated with death was leukopenia (P <t; .001). In multivariate analysis, leukopenia and erythroderma occurring within the first 24 h after admission to the hospital were independently associated with fatal outcome. Erythroderma was not associated with toxic shock syndrome toxin. Conclusions. Airway bleeding, erythroderma, and leukopenia are associated with fatal outcome from Panton-Valentine leukocidin–positive S. aureus necrotizing pneumonia. More work is needed to develop more efficacious therapy against this highly lethal disease.
Vitelliform degeneration of the macula Francçois, P; Turut, P
Archives d'ophtalmologie et revue generale d'ophtalmologie,
1975 Aug-Sep, Letnik:
35, Številka:
8-9
Journal Article
Macular vitelliform degeneration is an hereditary affection, with autosomal dominan transmission. It is probably congenital. Three phases in the evolution of lesions: I The "fried eggs" aspect. II ...Various ophthalmologic aspects: mixed egg, pseudo-hypopion, retractile form. During these first two phases, the yellowish vitelline substance only may extend in macular region, especially downards. III The atrophic phase. Visula acuity remains strangely good, especially during the first two phases. Nevertheless, the visual function study, especially colour vision and profile perimetry, elecites a precocious suffereance of macular cones, associated to fluorographic alteration of pigmentary epithelium in phases II and III. Actually, these lesions are mostly situated in perifoveolar area, respecting the foveola, which explains conservation of good vision. The electro-oculogram is deeply modified in most cases. The pathogenesis of this affection remains unexplained, but the evolution of lesions both in pigmentary epithelium and neuro-epithelium enables to think that vitellin substance lays between these two layers.
We describe the susceptibility to deltamethrin and fipronil of four sylvatic Triatoma infestans populations from the Andean valleys of Bolivia. Fifty percent lethal doses were determined from topical ...application of insecticide on first instars, and mortality was assessed after 24 h for deltamethrin and 48 h for fipronil. In comparison with a reference strain from Argentina, the Bolivian populations showed deltamethrin 50 percent lethal dose ratios ranging from 1.9 to 17.4. In the case of fipronil, an insecticide never used for control of T. infestans, the Bolivian populations showed even higher variation in toxic response, with relative susceptibilities ranging from 0.5 to 139.2. However, although the sylvatic T. infestans toxicological profiles differ from each other and from those of the domiciliary population studied in this work, there were no significant differences in the activities of P450 mono-oxygenases and pyrethroid esterases between the reference strain and the studied populations.
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