Recreation-induced changes in boreal bird communities in protected areas.

The impacts of human-induced disturbance on birds have been studied in growing extent, but there are relatively few studies about the effects of recreation on forest bird communities in protected areas. In this paper, the relative importance of recreation as well as environmental variables on bird communities in Oulanka National Park, in northeastern Finland, was investigated using general additive models (GAM). Bird data collected using the line transect method along hiking trails and in undisturbed control areas were related to number of visits, area of tourism infrastructure, and habitat variables. We further examined the impact of spatial autocorrelation by calculating an autocovariate term for GAMs. Our results indicate that number of visits affects the occurrence and composition of bird communities, but it had no impact on total species richness. Open-cup nesters breeding on the ground showed strongest negative response to visitor pressure, whereas the open-cup nesters nesting in trees and shrubs were more tolerant. For cavity-nesting species, recreation had no significant impact. The contribution of the number of visits was generally low also in models in which it was selected, and the occurrence of birds was mainly determined by habitat characteristics of the area. However, our results show that the recreation-induced disturbance with relatively low visitor pressure can have negative impacts on some bird species and groups of species and should be considered in management of protected areas with recreational activities.

Counting Linear Extensions: Parameterizations by Treewidth.

We consider the # P -complete problem of counting the number of linear extensions of a poset ( # LE ) ; a fundamental problem in order theory with applications in a variety of distinct areas. In particular, we study the complexity of # LE parameterized by the well-known decompositional parameter treewidth for two natural graphical representations of the input poset, i.e., the cover and the incomparability graph. Our main result shows that # LE is fixed-parameter intractable parameterized by the treewidth of the cover graph. This resolves an open problem recently posed in the Dagstuhl seminar on Exact Algorithms. On the positive side we show that # LE becomes fixed-parameter tractable parameterized by the treewidth of the incomparability graph.

Simultaneous visualization of wall motion, beam propagation, and implosion symmetry on the National Ignition Facility (invited).

Achieving a symmetric implosion in National Ignition Facility indirect drive targets requires understanding and control of dynamic changes to the laser power transport in the hohlraum. We developed a new experimental platform to simultaneously visualize wall-plasma motion and dynamic laser power transport in the hohlraum and are using it to investigate correlations of these measurements with the imploded capsule symmetry. In a series of experiments where we made one single parameter variation, we show the value of this new platform in developing an understanding of laser transport and implosion symmetry. This platform also provides a new way to evaluate dynamic performance of advanced hohlraum designs.

Use of high dose chloral hydrate for ophthalmic exams in children: a retrospective review of 302 cases.

Although chloral hydrate sedation has been proposed as an alternative to evaluation under anesthesia for pediatric patients who are unable to cooperate with routine test procedures, a careful study of the drug's safety and effectiveness is lacking. This study reports the effectiveness and safety of high-dose chloral hydrate for ophthalmic examination in 302 patients between the ages of 1 month and 5 years. The patients had nothing to eat or drink for 4 hours prior to drug administration. The patients were monitored during sedation and until fully awake. Eighty-eight percent of the patients (266/302) were successfully sedated without a supplemental dose. There were no reports of any complications including emesis, respiratory distress or depression, behavioral problems, changes in vital signs, patient injury, or hospital admission. The high-dose chloral hydrate protocol described, results in safe and generally successful sedation of pediatric patients for ophthalmic examination.

Non-thrombocytopenic purpuras.

88 cases of microscopical diapedesis of the red blood cells in the superficial blood vessels of the skin were investigated clinically, histologically and immunohistologically. Polymorphonuclear vasculitis (PMNV) was found in 27 cases, 18 of which also demonstrated immunoglobulins (mostly IgM) in the vessel walls. Complement (C3) was found in 16 cases. The cases with PMNV formed a uniform group as regards preceding infections, drug consumption, clinical features, and pathological urinalysis and laboratory data. The second group consisted of 21 cases of lymphocytic perivasculitis with immunoglobulins and/or complement (LP + ig/C3). It clearly differed clinically from the former group in three respects: urinalysis was normal, a slowing of the venous outflow was found in more than half of the cases and the duration of the disease was longer. The biggest group consisted of 40 cases of lymphocytic perivasculitis without detectable immunoglobulins in the vessel walls (LP). In this group the duration of the disease was shortest. The capillary resistance was lower than in the other groups. The results of this investigation indicate that there are at least three pathogenetically differing groups among the clinical purpuric conditions.

Intelligibility of synthetic speech for normal-hearing and hearing-impaired listeners.

This study examined the perceived intelligibility of synthetic speech. Participants were adults aged 49-69, one group with normal hearing and one group with acquired sensorineural hearing impairment. Word lists were presented in two speech types: DECtalk (a high-quality speech synthesizer) and a natural male speaker. Results revealed differences between groups, with normal-hearing listeners scoring higher than hearing-impaired listeners, and between speech types, with higher scores for natural speech than for synthesized speech. There was no significant interaction of hearing level and speech type.

Single-longitudinal-mode, tunable, pulsed Ti:sapphire laser oscillator.

A 2.0-mJ/pulse, 2-nsec, single-longitudinal-mode Ti:sapphire laser oscillator has been demonstrated in a compact grazing-incidence cavity configuration similar to a Littman arrangement. The oscillator's output beam quality is TEM(00), making it attractive for doubling and mixing applications. With currently available optics the laser is tunable over greater than 2500 cm(-1) from 746 to 918 nm.

Saturation of green absorption in titanium-doped sapphire laser crystals.

Saturation of the pump-band absorption in Ti:sapphire has been observed by using 10-nsec, pi-polarized pulses of 532 nm with fluences up to 4 J/cm(2). A Frantz-Nodvik method was used for fitting the data and determining the saturation fluence (7.6 J/cm(2)) and the absorption cross section (4.9 x 10(-20)cm(2)) at 532 nm. The peak absorption cross section was calculated to be 6.4 x 10(-20) cm(2) at 490 nm. This value is in reasonably good agreement with other determination methods.

Gluten-free diet in dermatitis herpetiformis. I. Clinical response of skin lesions in 81 patients.

Eighty-one patients with dermatitis herpetiformis were treated with a gluten-free diet (GFD) for periods varying from 6 to 36 months. At the end of the treatment the daily requirement of dapsone was significantly lower in patients treated with a GFD than in 49 patients on a normal diet. 93% of the patients on a GFD were able to reduce the dose of dapsone whereas only 16% of the patients on a normal diet were able to do this. Complete remissions occurred only in patients on a GFD. 28% of the patients on a GFD were able to stop dapsone completely and were continuously asymptomatic when they observed a strict diet. A response to a GFD was noted on the mean daily requirement of dapsone as soon as the treatment was initiated although the length of time for an individual response varied. After one year on a GFD the patients needed on average about 40% and after 3 years about 20% of the dose required to control skin symptoms at the beginning of the diet. The patients responded to a GFD irrespective of changes found in the jejunal mucosa and irrespective of the presence of absence of HLA-B8.