bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Time to Defibrillation and Subthreshold Preshocks on Defibrillation Success in Pigs
Authors: FUJIMURA OSAMU , JONES DOUGLAS L. , KLEIN GEORGE J. 
Published: July 2006

The purpose of this study was to examine the effects of: (1) time to defibrillation and (2) subthreshold preshocks on defibrillation success. We conducted two separate experiments in 19 anaesthetized, open‐chested pigs. Defibrillation was attempted using the sequential pulse technique approximately 10 s after electrically induced ventricular fibrillation. Each sequential pulse shock consisted of two trapezoidal puises (approximately 3 ms duration), separated by 0.2 ms. Current was delivered to three mesh electrodes (TX‐7, Medtronic) sutured over the anterior right ventricle, posterior right ventricle, and lateral left ventricle. For each animal, defibrillation threshold (DFT) defined as the lowest delivered energy that defibrillated the heart, was measured twice and the average was designated as mean DFT. The energy at 1.4 times the specific mean DFT for each pig was designated as the test shock and 100 volts less than the mean DFT was designated as the preshock.In the first experiment, test shocks were delivered at five different fibrillation intervals (10, 20, 40. 60, and 90 s). Time to test shock delivery was randomized for 10 to 60s, but, 90 s was always tested at the end of the study. Percentages of success at 10, 20, 40, 60, and 90 s were 94, 78, 94, 83, and 100%, respectively (p = NS). The 12 pigs in which all initial test shocks were successful were selected for the evaluation of post defibrillation arrhythmias. The cumulative incidence of complete heart block lasting at least 5 s were 8, 33, 83, 83, and 83%, respectively. The incidence of complete heart block increased significantly at 40 s (p < 0.001). Ventricular arrhythmias were observed on six occasions at 40 s or later.Following experiment 1, the pigs were allocated to three groups (n = 6 for each group). Group 1 received one preshock, Group 2, two preshocks and Group 3, three preshocks. Each pig had 16 test shocks, eight with no preshock and eight with one of single, double or triple preshocks within 15 s after ventricular fibrillation onset. The test shock was delivered at 20 s. There were no intra‐ or intergroup differences in percentage of success regardless of number of subthreshold preshocks.We conclude that delay of defibrillation therapy up to 90 s and delivery of preshocks have no significant effect on the ability to defibrillate the heart in this model. However, delay to 40 s and longer is associated with a higher incidence of complete heart block and ventricular arrhythmias.
Analog‐Digital Recording of Current and Voltage During High Voltage DC Shocks
Authors: PETERS WERNER , SCHARF RAINER , MEESMANN MALTE 
Published: July 2006

Efficient on‐line digitization is the prerequisite for computerized analysis of the electrical phenomena occurring during defibrillation. Conventional hardware presently provides only limited time resolution. The performance of various digitization rates for recording of voltage, current, and calculation of derived quantities like impedance, energy, and defibrillator capacitance was investigated. It was assessed both experimentally and by computer simulation of a trapezoidal discharge (of 9 msec duration into a constant resistive load of 50 Ω with a defibrillator capacitance of 132 μF). The accuracy achieved with different digitization rates is given. For example, an accuracy of 1% for analog‐digital conversion for impedance calculation during this kind of DC shock requires a sampling rate of 8 kHz without, and a rate of 1 kHz with linear interpolation to correct for the hardware dependent error due to sequential sampling.Conclusion: Highly efficient analog‐digital conversion of delivered voltage and current during DC shocks is available within the limits of conventional inexpensive hardware.
Electrophysiological Effects of Intrapericardial Infusion of Endothelin‐1
Authors: GELLÉR LÁSZLÓ , MERKELY BÉLA , SZOKODI ISTVÁN , SZABÓ TAMÁS , VECSEY TIBOR , JUHÁSZ‐NAGY ALEXANDER , TÓTH MIKLÓS , HORKAY FERENC 
Published: July 2006

Recently, extremely high levels of endothelin‐1 (ET‐1) were detected in the pericardial fluid of patients undergoing open‐heart surgery. ET‐1 has been suggested to have direct arrhythmogenic effect on myocardium. The aim of the present study was to examine the putative arrhythmogenic effect of intrapericardial infusion of ET‐1 in anesthetized dogs (n=15).In preliminary experiments, ET‐1 (0.125–1.0 nmol/min, n=7) was infused into the closed pericardial sack for 40 min. ET‐1 induced non‐sustained and/or sustained ventricular tachyarrhythmias in all but the lowest dose. For detailed arrhythmia analysis in addition to standard ECG ventricular endocardial and epicardial monophasic action potentials (MAP) were recorded. ET‐1 (0.250 nmol/min, n=7) induced mono‐ and polymorphic ventricular tachycardias, which (degenerated into ventricular fibrillation in two instances. Moderate if any ischemic signs could be detected before the onset of arrhythmias. The arrhythmias spontaneously disappeared in all instances with the exception when ventricular fibrillation terminated the experiment. QT interval (260±23ms vs. 317±31ms, P < 0.05), and endo‐ and epicardial MAPD90 (at 300 ms cycle length) prolonged significantly (in average 182±12ms vs. 224±25ms, P < 0.05). Using MAP recording afterdepolarizations were detected in three instances. In control animals (n=3) arrhythmias were not observed and all electrophysiological parameters remained unchanged.The present results show that intrapericardial administration of ET‐1 can induce ventricular arrhythmias in dogs. The arrhythmogenic effect of ET‐1 may be based on prolongation of MAP duration and development of afterdepolarizations. However, the elucidation of the precise mechanism needs further investigation.
Pacemaker‐Related Patient Mortality
Authors: IRNICH WERNER 
Published: July 2006

Little is known about the incidence of technical defects and malfunctions of pacemaker pulse generators. During 1986 only 2 articles of 13 in PACE gave concrete failure numbers: between 1.2% and 3.4% per year. Our estimation of technical failure rates gained by evaluating the data of the German Pacemaker Registry varied between 2 × 10−3 annually in 1992 and 0.7 × 10−3 annually in 1997. This data was derived from clinical information about pulse generator replacements required due to a technical defect. Are the numbers derived from replacement procedures a complete picture of the failure incidence?Two additional sources were evaluated to answer this question: the “death related file closure” data of the German Pacemaker Registry and the testing of 3,050 pacemakers removed from deceased patients. The results seem to indicate that there may be three times as many generator defects as calculated from replacement data. About one‐third of the defective generators were found in deceased patients, which led to the question of how this can be explained. Roughly another third was reported by the physicians to be the cause of the patient's death. If one hypothesizes that the same situation and ratios will exist for other critical situations such as sensing or lead defects, a total annual defect or malfunction incidence of 3.8 × 10−3 can be projected. The majority of malfunctions remains undetected during the lifetime of the pacemaker patients. The minority only can be detected if the patients survive situations. As the mean lifetime of a pacemaker patient is 6 years after implant, at least in Germany, 1 of 62 patients died in the past with or, alternatively, because of a recognized or unrecognized malfunction of the pacemaker system.
Vole diet on experimentally managed reforestation areas in northern Sweden
Authors: Hansson Lennart , Larsson Tor‐Björn 
Published: July 2006

In northern Sweden two field experiments with the reforestation techniques soil scarification, ploughing, burning and grass herbicidal treatment were performed. Small rodents were trapped regularly on the managed plots and their stomachs were examined microscopically for diet composition. Both bank voles Clethrionomys glareolus and field voles Microtus agrestis were common on the reforestation areas while only a small number of grey‐sided voles Clethrionomys rufocanus were taken. All three species underwent a population cycle during the studies. The management techniques generally resulted in small and irregular effects on the food selection. The most pronounced changes were lower intake of grasses by M. agrestis after herbicidal treatment and of filamentous tree lichens by C. glareolus after most treatments.Both bank voles and field voles ate predominantly forbs in the summer half of the year, whereas the field voles took also a considerable amount of grass. As a complement to green vegetable‐matter bank voles ate berries and fungi in summer‐autumn and tree lichens at other times of the year, but seeds and animals food only in very small amounts. Ail three species consumed large quantities of dwarf‐shrubs in autumn and especially in winter. Considerable amounts of bark were eaten by field voles and a smaller proportion by bank voles in autumn‐winter.Both for bank and field voles there were indications of worsening food conditions as the population cycle went on, There were, for example, an increase in grass and bark intake in field voles and a decrease in seeds and berries for the hank vole.
The Plecoptera of Øvre Heimdalsvatn
Authors: Lillehammer Albert 
Published: July 2006

The stonefly fauna was studied in the exposed zone and on soft bottom in deeper waters. Emergence was recorded by traps. Ten species were found. All were recorded in the exposed zone. Diura bicaudata (L.) and Nemoura avicularis Morton dominated.During the winter N avicularis occurred in large numbers on soft bottom at nearly all depths while D. bicaudata was only recorded on stony substratum in shallow water. N. avicularis was therefore more susceptible to predation and was recorded in trout stomachs during most of the year, while D. bicaudata was preyed upon only during the short emergence and flight period.The growth of the most numerous plecopteran species took place partly while the lake was covered by ice. D. bicaudata had two thirds of its growth during this period, while N. avicularis only had one third of its growth during the same period.
The Trichoptera of Øvre Heimdalsvatn
Authors: Lillehammer Albert 
Published: July 2006

Trichopteran larvae were sampled on soft substrata at all depths, on stony substrata in the exposed zone, and the adults in emergence traps, placed along the lake shore. Fourteen species were taken as larvae in the lake. On stony substrata and in the exposed zone Polycentropus flavomaculatus (Pictet) was dominant, followed by Limnephilus nigriceps (Zetterstedt) in terms of numbers. In terms of biomass L. nigriceps dominated followed by Potamophylax cingulatus (Stephens).Species which usually inhabit running water made up for a larger part of the trichopteran fauna of the exposed zone.The two most numerous species showed different habit preferences. P. flavomaculatus was most common on stable stony bottom, while L. nigriceps was most common on unstable stony bottom. The other species showed no significant preference. On unstable soft bottom at 3 m and below, Mystacides azureus (L.) dominated, accounting for about 90% of the total trichopteran fauna both in terms of weight and numbers.The major trichopteran species in the lake were either detritus feeders, such as M. azureus, L. nigriceps and Potamophylax spp. or omnivores such as P. flavomaculatus and Molanna albicans (Zetterstedt).
Mercury and chlorinated hydrocarbons in the food chain of Lake Päijänne, Finland
Authors: Särkkä Jukka , Hattula Marja‐Liisa , Paasivirta Jaakko , Janatuinen Jorma 
Published: July 2006

The sediments and various organisms in Lake Päijänne were examined for contaminants. The average mercury content of water plants was 9, of plankton 14, of sediment 114, of zoobenthic predators 83, of fish 332–1510 and of birds 240–13685 μg kg−1 (wet weight). The average PCB content of plants was 3, of plankton 21, of the zoobenthos 44, of fish 36‐117 and of birds 219–13490 μg kg−1. The average ΔDDT content of plants was 0.5, of plankton 6, of the zoobenthos 14, of fish 7–42 and of birds 144‐8262 μg kg−1. Regional differences in mercury content were most pronounced in sediment and fish. PCB concentration was highest near a town. ΔDDT was quite evenly distributed. Water plant species did not differ from each other, nor did the plankton fractions. The zoobenthic predators contained more chlorinated hydrocarbons than did the herbivores. There were clear differences between most species of fish and the chlorinated hydrocarbon content was highest in vendace. In adult birds levels of all residues were significantly higher than in juveniles.In most cases PCB content was positively correlated with ΔDDT and in birds PCB, ΔDDT and mercury levels were correlated. DDT residues occurred mostly as DDE, but in vendace the proportion of DDT was high. At most trophic levels, ΔDDT/PCB was 0.15‐0.40 but in birds it reached 1–2.
Changes in bird populations as criteria of environmental changes
Authors: Järvinen Oili , Väisänen Risto A. 
Published: July 2006

Järvinen, O. and Väisänen, R. A. 1979. Changes in bird populations as criteria of environmental changes. – Holarct. Ecol. 2: 75‐80.Birds are a powerful tool of environmental monitoring, on account of their ecological diversity. Because of this, bird populations seem best suited for monitoring biological, possibly non‐linear effects of specified environmental changes, such as habitat modification, and for “general monitoring” aimed at detecting unexpected environmental changes as they occur. Because many population changes have multiple causes, monitoring specific environmental changes is most rewarding if birds are grouped by e.g. habitat, major strategy (e.g. resident vs. migrant species), or feeding guild. A blueprint for a Nordic monitoring system based on breeding land birds is presented. Local trends may be atypical, and representative coverage of the major habitats in large areas should thus be ensured. As annual population fluctuations usually give little information in environmental monitoring, long‐term projects are necessary. The line transect method seems applicable to many monitoring purposes, as it is rapid, inexpensive, relatively accurate, and suitable for sampling the northern terrestrial biota of the Holarctic region, probably including the temperate deciduous forests.
Size and composition of the wild reindeer Rangifer tarandus platyrhynchus population in the Southeast Svalbard Nature Reserve
Authors: Alendal Einar , de Bie Steven , van Wieren Sipke E. 
Published: July 2006

Alendal, E., de Bie, S. and van Wieren, S. E. 1979. Size and composition of the wild reindeerRangifer tarandus platyrhynchuspopulation in the Southeast Svalbard Nature Reserve. Holarct. Ecol. 2: 101‐107.In the summer of 1977 we studied the reindeer population on the islands Barentsøya and Edgeøya in the eastern part of the Svalbard archipelago. A total of 1374 reindeer were observed: 326 animals in the western parts of Barentsøya and 1048 animals on Edgeøya. Considering those parts of Edgeøya which were not visited, the total number of reindeer on Edgeøya was estimated at 1300 animals. The total number of reindeer was lower than in previous years. The decline probably was due to severe winter conditions in 1975/1976 and 1976/1977 confirmed by the fact that many carcasses and few yearlings were observed.Nearly all reindeer occurred on the coastal plains and in the valleys. These areas have the relatively richest vegetation. The average recruitment of the total population (counted) was 15.9%. The adult sex ratio was in favour of females: 59% females versus 41% males. There were differences both in the recruitment and in the adult sex ratio between three distinct areas on Edgeøya and between two on Barentsøya. These differences may be due to dissimilarities in food quality and feeding conditions caused by climate, and by small exchange of reindeer between the areas.The high frequency of shed male antlers on Frankenhalvøya and Talaveraflya, north and south coast of Barentsøya respectively, indicates that these areas belong to the wintering grounds of reindeer on this island. Concentrations of shed female antlers on Barentsøya were less pronounced. The highest frequency was in the areas Sjodalen and Kvistdalen‐Talaveraflya in the northwest and south respectively. Females may use these areas as late wintering grounds and possibly as calving areas.The average group size was 2.2 and the aggregation index 3.1. Seventytwo per cent of all groups, containing 48% of all reindeer, fell into group size 1 and 2. Males mostly were observed alone or together with one other animal. Females with calves most frequently occurred in groups of 2 and 4 animals.
Biology of Hypogastrura tullbergi (Collembola) at a high arctic site
Authors: Addison Janter A. 
Published: July 2006

The life cycle, reproductive biology and growth rates of Hypogastrura tullbergi (Schäffer), one of the most abundant and widespread Collembola on Devon Island, N.W.T., were investigated.Reproductive activity was confined to a period of 2–4 wk every season, starting approximately 2 wk after snow‐melt. Individuals of H. tullbergi had the potential of breeding in at least 2 successive summers. This species had an extended, flexible life cycle with a total life span of approximately 3 yr.Growth rates of individuals of H. tullbergi maintained at field temperatures with an excess of fungal material greatly exceeded growth rates of individuals in the field population. It is suggested that in the field, growth rates are limited by food rather than directly by low temperatures. H. tullbergi was not able to grow on a diet of decomposing Dryas integrifolia leaves. Growth rates on fungal substrates were found to depend on temperature, species of fungus, and age. Maximum growth rates for adults occurred at 10°C, but juveniles showed a maximum growth rate at 15°C.The adaptive significance of aspects of the biology of H. tullbergi for long‐term survival in tundra environments is discussed.
Activity of Arthropoda in snow within a coniferous forest, with special reference to Collembola
Authors: Leinaas Hans Petter 
Published: July 2006

Winter activity of arthropods from the forest floor were studied in snow and the subnivean space. All but one epedaphic (soil surface dwelling) Collembola species moved up into the snow during winter. Three groups of activity patterns were found. (1) Hypogastrura socialis had a complex behaviour, moving up and down in the snow profile depending on the temperature. It was often found in large numbers on the surface. (2) Other species were occasionally observed on the snow surface, but were usually found in the deeper part of the snow profile. (3) Most epedaphic species were only found in the deeper part of the snow profile. Activity in the snow is assumed to be related to microclimatic conditions occurring mainly in late winter. However, the behaviour pattern is also influenced by the summer ecology of the species.Some collembola and most other arthropods found in the snow were only casual visitors from trees and soil. However, one oribatid species and some predaceous Gamasina mites did also show distinct snow behaviour.
Structure in seven bumblebee communities in eastern Finland in relation to resource availability
Authors: Ranta Esa , Tiainen Mauri 
Published: July 2006

The structure of seven local bumblebee communities was studied in eastern Finland. The number of species in the study sites varied from 5 to 10, 11 being the number in the species pool. Most of the species (queens) had proboscis lengths of 8–11 mm. When floral resources were analysed on the basis of corolla tube depths, a group was found between 4 and 8 mm. In terms of flower utilization, species with similar proboscises had higher pairwise niche overlaps than species differing by their proboscis lengths.Spacing between neighbouring species along the proboscis length dimension was not more uniform in the realized communities than what was expected on the basis of random draws from the local species pool. The results were the same for all species observed in the communities and for the abundant species only (frequency >5%), although competition among species in the latter group is expected to be more intense.When the structure of bumblebee communities and of floral resources was expressed in terms of diversity of proboscis lengths and corolla tube depths, respectively, a positive correlation was found. Data suggest that species with similar proboscis tend to co‐occur on fields with availability of appropriate corolla tubes.
The carabid communities on peat and upland grasslands in northern England
Authors: Butterfield Jennifer , Coulson J. C. 
Published: July 2006

During a two year period 13498 individuals of 66 species of carabids were taken from 44 sites on peat and upland grasslands over an altitude range of 11‐847 m in the north of England. The similarities between the carabid faunas of each site have been assessed using a modified form of the Sørensen's Index and the sites clustered according to their similarities. Five carabid communities on peat and three on mineral soils have been identified and the more abundant species have been used to characterise them. Peat Community I occurs on dry heath and is characterised by peat associated species such as Trichocellus cognatus and Bradycellus ruficollis together with widespread open habitat species such as Pterostichus madidus, Notiophilus aquaticus, Calathus melanocephalus and Nebria salina. Peat Community II is found on areas where dry heath and deep wet peat are adjacent and is characterised by the species already mentioned together with typical wet habitat species such as Pterostichus diligens, P. nigrita, Patrobus assimilis. Agonum fuliginosum. Peat Community III is found on blanket bog and is characterised by the wet habitat species in the absence of the species present on the dry heath. Peat Community IV found on the lowland oligotrophic mires is characterised by the small number of species present and the addition of Pterostichus niger and Agonum ericeti to the few wet habitat species present. Peat Community V, on the scarp slope of Dun Fell, consists of the wet habitat species of Peat Community III together with Pterostichus madidus. Nebria salina, Notiophilus aquaticus and Calathus melanocephalus.Grassland Community I, on the fell tops, is characterised by the presence of Nebria gyllenhali, Notiophilus germinyi and Patrobus assimitis. Grassland Community II and III are less clearly defined but Grassland Community II may be present on wetter sites than III and is characterised by the presence of Pterostichus nigrita, P. diligens and P. strennus together with Notiophilus biguttatus. N. aquaticus, Pterosfichus madidus and Patrobus afrorufus. Grassland Community III consists of the latter group of species together with Nebria salina, Calathus melanocephalus and Notiophilus aestuans. The number of grassland sites studied was small and there may be further communities on the upland grasslands.