Altitudinal segregation between Ural Owl Strix uralensis and Tawny Owl S. aluco: evidence for competitive exclusion in raptorial birds

Capsule The Owls were significantly segregated in space with the most important factor being altitude.

Aims To establish if the segregation between Ural and Tawny Owl on the level of habitat selection is due to different habitat requirements of the species or a consequence of competitive exclusion.

Methods Seven variables were recorded for habitat of Ural Owls, Tawny Owls that live in sympatry with Ural Owls and Tawny Owls that live in allopatry with Ural Owls. Data were gathered in five mountain areas covered with similar continuous montane forest inside and outside known Ural Owl distribution in Slovenia. Owl territories were surveyed in 2001 using playback method. Evidence for segregation was searched for using discriminant function analysis.

Results The altitudinal distribution of Tawny Owls sympatric to Ural Owls was restricted to low elevations with Ural Owls at high elevations. Where Ural Owls were absent, Tawny Owls widened the altitudinal part of their ecological niche to the mountaintop.

Conclusion Segregation between Tawny and Ural Owls is due to competitive exclusion, with the less competitive Tawny Owl being out-competed by the superior Ural Owl. The forests at foothills are influenced by human presence and therefore avoided by Ural Owls. In areas where both species live in sympatry, these areas act as refugia for Tawny Owls.     

Signal amplification in biological and electrical engineering systems: Universal role of cascades

In this paper we compare the cascade mechanisms of signal amplification in biological and electrical engineering systems, and show that they share the capacity to considerably amplify signals, and respond to signal changes both quickly and completely, which effectively preserves the form of the input signal. For biological systems, these characteristics are crucial for efficient and reliable cellular signaling. We show that this highly-efficient biological mechanism of signal amplification that has naturally evolved is mathematically fully equivalent with some man-developed amplifiers, which indicates parallels between biological evolution and successful technology development.     

Nest site selection and predation driven despotic distribution of breeding long-eared owls Asio otus

Long-eared owls Asio otus do not build their own nests. They occupy old corvid nests in either coniferous or deciduous trees. In my study area owls favoured coniferous over deciduous trees for nesting and occupied nest sites in that order. Comparing overall breeding output, I found no difference between the two kinds of nest sites, but among early nests there was a higher proportion of unsuccessful nests in deciduous trees. This difference was due to differences in predation rate, indicating that the owls' pattern of nest site occupation followed predictions from the ideal despotic distribution model. I also show that, due to a seasonal change in habitat quality, predator driven despotism, although present, can be well masked and hence difficult to detect.     

Duke Treadmill Score in prioritizing patients for coronary angiography: retrospective study of a Croatian regional hospital

Aim of the study was to determine the potential of Duke Treadmill Score (DTS) in prioritizing patients for coronary angiography in a transitional country clinical setting. We analyzed 114patients with suspected stable coronary artery disease who underwent exercise treadmill testing, and coronary angiography in Slavonski Brod General Hospital. DTS was calculated from treadmill test as: exercise time--(5 x ST deviation in mm)--(4 x exercise angina). Regarding the score, patients were grouped into three groups of risk for coronary artery disease: low risk, medium risk, and high risk patients. All patients underwent coronary angiography, and were grouped in accordance to the severity of the coronary artery disease into three groups: insignificant, significant, or severe coronary artery disease. All patients scored as high risk DTS had significant or severe coronary artery disease. Medium and low risk DTS patients had insignificant coronary artery disease in 50%, and 90% of cases, respectively. Medium risk patients with significant or severe coronary artery disease were significantly older, and had more frequent history of typical chest pain with higher number of episodes per week (P<0.05), whereas there were no differences regarding gender or presence of risk factors. There were no significant differences among medium risk patients regarding the severity of coronary artery disease in exercise time or ST deviation. However, the presence of limiting exercise angina in medium risk patients was significantly more related with significant and severe coronary artery disease (P<0.05). High risk DTS result showed great potential in stratifying patients for immediate coronary angiography. This scoring system may be used in prioritizing patients for coronary angiography in a transitional clinical setting.     

Evidence for senescence in survival but not in reproduction in a short‐lived passerine

Senescence has been studied since a long time by theoreticians in ecology and evolution, but empirical support in natural population has only recently been accumulating. One of the current challenges is the investigation of senescence of multiple fitness components and the study of differences between sexes. Until now, studies have been more frequently conducted on females than on males and rather in long‐lived than in short‐lived species. To reach a more fundamental understanding of the evolution of senescence, it is critical to investigate age‐specific survival and reproduction performance in both sexes and in a large range of species with contrasting life histories. In this study, we present results on patterns of age‐specific and sex‐specific variation in survival and reproduction in the whinchat Saxicola rubetra, a short‐lived passerine. We compiled individual‐based long‐term datasets from seven populations that were jointly analyzed within a Bayesian modeling framework. We found evidence for senescence in survival with a continuous decline after the age of 1 year, but no evidence of reproductive senescence. Furthermore, we found no clear evidence for sex effects on these patterns. We discuss these results in light of previous studies documenting senescence in short‐lived birds. We note that most of them have been conducted in populations breeding in nest boxes, and we question the potential effect of the nest boxes on the shape of age‐reproductive trajectories.     

Micro-regional hypersensitivity variations to inhalant allergens in the city of Zagreb and Zagreb County

Depending on the geographic and climatic region and vegetation, allergenic plants are characteristic for certain areas and the pollen concentrations of various plant species depend on the fenophase of each single species and most of all on the climatic and meteorological conditions of a certain area. It is precisely because of these specific characteristics that the hypersensitivity of patients to various types of pollen allergens differs according to the geographic regions. The aim of this paper is to determine the frequency of inhalation allergies in adult population (> 19 years of age) caused by single types of allergens according to the defined space units (micro-regions) with special emphasis on the rural and urban areas. A number of 2,192 patients have been tested for allergy skin prick tests over a period of four years. Every patient was asked to fill in the questionnaire which contained 29 questions. The results of skin prick testing show that out of a total of 2,192 patients 86.72% were sensitized to pollen, 36.45% to mites, 2.46% to spores of fungi and mould and 5.1% of patients to other allergens which include the allergens of cockroaches, feathers and animal hair (p < 0.001). The largest number of poly-sensitized persons allergic to pollen allergens was sensitized to allergens from the pollen of plants that belong to the botanical family of grass. There were 25.36% patients mono-sensitized to individual allergens. In the northern and western parts of the city and the county, the majority of persons were sensitized to the birch pollen allergens, and this is statistically much more than the share of patients with the place of residence in the southern and eastern parts of the city and the county. In the southern and eastern locations prevails the share of sensitized persons to ambrosia which is statistically much more than the share of patients with the place of residence in the northern and western part of the city and the county.     

Pulmonary compliance values provide prognosis in mechanically ventilated patients--a randomized prospective study

Our aim was to evaluate the influence of static pulmonary compliance (Cst) on the choice of Mechanical Ventilation(MV) method and treatment outcome. A prospective, randomized trial conducted out at the multidisciplinary Intensive Care Unit (ICU) included 387 patients, randomized in two groups: noninvasive MV group and invasive MV group. Furthermore, each group was divided in two groups: Cst < or = 0.025 and Cst > 0.025 L/cm H2O. In patients with Cst > 0.025 L/cm H2O MV duration, noninvasive vs invasive, was 92 vs 114 h, p = 0.039, time spent in ICU 118 vs 164 h, p = 0.004. In patients with Cst < or = 0.025, MV duration was 141 vs 189 h, p < 0.001, time spent in ICU 190 vs 246 h, p = 0.001, all patients were intubated. Need for tracheostomy was 6 (11%) vs 39 (46%) patients, p = 0.005, and ICU mortality was 15 (26%) vs 21 (25%) patients. Statistical significance in favor of noninvasive method was confirmed in patients with Cst > 0.025 L/cm H2O in MV duration, time spent in ICU, need for tracheostomy and intubation rate. In the group with Cst < or = 0.025 no significant difference in treatment failure was recorded between the two MV methods.     

Viruses, plasmids and other genetic elements of thermophilic and hyperthermophilic Archaea

We review and update the work on genetic elements, e.g., viruses and plasmids (excluding IS elements and transposons) in the kingdom Crenarchaeota (Thermoproteales and Sulfolobales) and the orders Thermococcales and Thermoplasmales in the kingdom Euryachaeota of the archael domain, including unpublished data from our laboratory. The viruses of Crenarchaeota represent four novel virus families. The Fuselloviridae represented by SSV1 of S. shibatae and relatives in other Sulfolobus strains have the form of a failed spindle. The envelope is highly hydrophobic. The DNA is double-stranded and circular. Members of this group have also been found in Methanococcus and Haloarcula. The Lipothrixviridae (e.g., T TV1 to 3) have the form of flexible filaments. They have a core containing linear double-stranded DNA and DNA-binding proteins which is wrapped into a lipid membrane. The ‘Bacilloviridae’ (e.g., TTV4 and SIRV) are stiff rods lacking this membrane, but also featuring linear double-stranded DNA and DNA-binding proteins. Both virus type carry on both ends structures involved in the attachment to receptors. Both types are represented in Thermoproteus and Sulfolobus. The droplet-formed novel Sulfolobus virus SNDV represents the ‘Guttaviridae’ containing circular double-stranded DNA. Though head and tail viruses distantly resembling T phages or lambdoid phages were seen electronmicroscopically in solfataric water samples, no such virus has so far been isolated. SSV1 is temperate, TTV1 causes lysis after induction, the other viruses found so far exist in carrier states. The hosts of all but TTV1 survive virus production. We discuss the implications of the nature of these viruses for understanding virus evolution. The plasmids found so far range in size from 4.5 kb to about 40 kb. Most of them occur in high copy number, probably due to the way of their detection. Most are cryptic, pNOB8 is conjugative, the widespread pDL10 alleviates in an unknown way autotrophic growth of its host Desulfurolobus by sulfur reduction. The plasmid pTIK4 appears to encode a killer function. pNOB8 has been used as a vector for the transfer of the lac S (β-galactosidase) gene into a mutant of S. solfataricus.     

Mineralogy of shells from two freshwater snails Belgrandiella fontinalis and B kuesteri

X-ray powder diffraction (XRD) was used to study the mineral composition of shells of snails Belgrandiella fontinalis and Belgrandiella kuesteri collected from three freshwater springs in northeastern Slovenia. The fractions of aragonite, calcite, dolomite and quartz in particular shells were determined. The analysed shells consisted of two or more distinct inorganic layers. The outer shell layer for both species and all sampling localities contained aragonite. The outer layer of B. fontinalis collected at one locality, also contained a small fraction of calcite ( approximately 1 molar%) besides the dominant aragonite. Calcite was identified in the inner layer(s) of both species (2 to 3 molar%), while quartz was found only in B. kuesteri (5-7 molar%). However, both species sampled at one locality showed the presence of dolomite (approx. 20 molar%) in the inner layer(s). The presence of dolomite in the shells of adult gastropods and even molluscs is unusual. A possible formation mechanism and specific ecological factor that could influence the precipitation of dolomite in the shells of different Belgrandiella species is discussed.