bluuebunny/crossref_metadata_2025 huggingface dataset:
Low Temperature and Low Energy Radiofrequency Modification of Atrioventricular Nodal Slow Pathways in Pediatric Patients
Authors: RHODES LARRY A. , WIEAND TAMMY S. , VETTER VICTORIA L.
Published: July 2006

Objectives: To report our experience using low temperature and energy in the modification of the slow pathway in pediatric patients with atrioventricular nodal reentrant tachycardia. Background: A concern in performing a slow pathway modification is the possible damage of the normal AV conduction system. Lesion size has been shown to have a linear relationship with temperature. Previous reports have used energy of 25–50 W that generate temperatures of 60C°–70°C for successful procedures. Methods: Report of results of attempted AV nodal slow pathway modification in 17 consecutive pediatric patients < 15 years of age at The Children's Hospital of Philadelphia from April 1995 to November 1997 using low temperature and energy. Results: There were 18 successful slow pathway modifications with 1 recurrence in 17 patients. The maximum energy used during successful lesions was 32.7 ± 13.8 W (range 15–50 W) with a mean energy of 26.4 ± 13.3 W (range 12–48 W). The peak temperature during these lesions was 55.1°C ± 4.1°C (range 48°C–64°C) with a mean temperature of 47.9°C ± 2.7°C (range 44°C–54°C). The mean number of radiofrequency lesions required for a successful modification was 5.8 ± 6.7 (median 4.0, range 1–26). Patients have been followed for 2.08 ± 0.79 years. Conclusions: Slow pathway modification can be performed successfully with a low incidence of recurrence in the pediatric patient using low energy and temperature. It is possible that this may lead to smaller lesions.
Impact of Long‐Term ECG Recording on the Detection of Paroxysmal Atrial Fibrillation in Patients After an Acute Ischemic Stroke
Authors: SCHUCHERT ANDREAS , BEHRENS GINA , MEINERTZ THOMAS
Published: July 2006

An ECG recording time of 24 hours has a low yield to detect atrial arrhythmias in patients after an acute ischemic stroke. The present study investigated whether a recording time of 72 instead of 24 hours detects paroxysmal atrial fibrillation in more patients. The study prospectively included 82 consecutive patients 2–3 weeks after an acute ischemic stroke. All patients had sinus rhythm in the resting ECGs and no history of atrial fibrillation or flutter. The frequency of atrial fibrillation was assessed after 24, 48, and 72 hours of ambulatory ECG monitoring. An ECG monitoring time of 72 hours documented paroxysmal atrial fibrillation in five (6%) patients. The episode of paroxysmal atrial fibrillation occurred in only one patient within 24 hours. The other patients had their first episode of atrial fibrillation between 24 and 48 hours (n = 2) and between 48 and 72 hours (n = 2). These five patients were older (age = 70 ± 5 years), whereas the mean age of the remaining patients was 59 ± 13 years. All five patients had cardiovascular disease in comparison to 36 of 77 patients and reported palpitations in comparison to 6 of 77 of the remaining patients. In conclusion, ambulatory ECG monitoring over 72 hours detected after the first recording day four of five patients in whom paroxysmal atrial fibrillation could be documented for the first time. The 72‐hour recording time improved, compared to the 24‐hour period, the detection of paroxysmal atrial fibrillation in patients after an ischemic stroke. It seems to be more efficient to perform prolonged ECG recording mainly in older patients with a cardiovascular disease and/or a history of palpitations.
Percutaneous Extraction of an Abandoned Coiled Pacing Lead
Authors: LICKFETT LARS , JUNG WERNER , PIZZULLI LUCIANO , WOLPERT CHRISTIAN , LÜDERITZ BERNDT
Published: July 2006

Abandoning redundant pacing leads has been an accepted practice in most cases. Late migration of a lead is a rare, unpredictable, and potentially lethal complication of this approach and requires immediate removal. We report the case of an atrial pacing lead that had migrated and was found coiled in the right atrium. It was removed by a snare catheter via a femoral approach.
Absence of the Superior Vena Cava: Difficulties for Pacemaker Implantation
Authors: DEL OJO J. LEAL , JIMENEZ C. DELGADO , VILCHES P. JIMENEZ , SERRANO A. LESMES , GUTIERREZ F. LOZANO , RODRIGUEZ J. BELTRAN
Published: July 2006

Endocardial pacemaker electrode implantation can be difficult in patients with anomalous superior vena cava (SVC). Venography and CAT scan showed that the patient lacked SVC venous drainage and that systemic veins drained into the inferior vena cava through the azygos vein. A temporary stimulation electrode was placed by puncture of the femoral vein, permanent stimulation by venotomy of the epigastric vein, with the electrode inserted through the external iliac vein.
Perforation of the Right Ventricular Free Wall by an Active Fixation Transvenous Cardioverter Defibrillator Lead
Authors: SHOHAT‐ZABARSKI RONIT , KUSNIEC JAIRO , STRASBERG BORIS
Published: July 2006

A 58‐year‐old patient with dilated cardiomyopathy underwent implantable cardioverter defibrillator (ICD) implantation. The postoperative course was complicated by perforation of the right ventricular free wall by the active fixation transvenous ICD lead. The type of ICD lead and the type of organic heart disease are apparently important risk factors for perforation.
Experience with a Low Profile Bipolar, Active Fixation Pacing Lead in Pediatric Patients
Authors: CAMPBELL ROBERT M. , RAVIELE ANTHONY A. , HULSE EDDIE J. , AULD DEBBIE O. , McRAE GUYLER J. , TAM VINCENT K.H. , KANTER KIRK R.
Published: July 2006

Continued miniaturization of permanent pacing systems has promoted use of this technology in younger and smaller pediatric patients. Intermedics ThinLine 438–10 active fixation pacing leads (4.5 Fr lead body) were implanted in 26 patients (17 males/9 females; 9.9 ± 6.9 years). Twenty of 26 patients received dual chamber systems, 6 of 26 patients single lead systems. Each patient has been followed3 3 months. Pacemaker analysis at implant and 6 months later evaluated pulse width thresholds at 2.5 V (atrial 0.07 ± 0.02 vs 0.13 ± 0.02 ms [P = 0.01]; ventricular 0.08 ± 0.04 ms vs 0.20 ± 0.04 ms [P = 0.01]); sensing thresholds (atrial 4.1 ± 0.41 mV vs 4.0 ± 4.2 mV [P = NS]; ventricular 9.7 ± 0.72 vs 9.3 ± 0.94 mV [P = NS]); and impedance (atrial 345 ± 12 vs 370 ± 120 O [P = 0.04]; ventricular 412 ± 17 vs 458 ± 190 O [P < 0.01]). One volt lead failed with exit block at approximately 6 weeks. The youngest (9 months to 5 years) and smallest (6.5–18.0 kg) ten patients have each shown by venography to have at least mild venous stenosis at the lead(s) insertion site; five patients demonstrated collateral formation around asymptomatic obstruction, with no thrombus formation. The Intermedics 438–10 ThinLine pacing lead has demonstrated good and stable early postimplant electrical parameters. Angiographic evaluation in our smaller patients has shown evidence for asymptomatic venous obstruction.
Nonfluoroscopic Localization of an Amagnetic Stimulation Catheter by Multichannel Magnetocardiography
Authors: FENICI RICCARDO , NENONEN JUKKA , PESOLA KATJA , KORHONEN PETRI , LÖTJÖNEN JYRKI , MÄKIJÄRVI MARKKU , TOIVONEN LAURI , POUTANEN VELI‐PEKKA , KETO PEKKA , KATILA TOIVO
Published: July 2006

This study was performed to: (1) evaluate the accuracy of noninvasive magnetocardiographic (MCG) localization of an amagnetic stimulation catheter; (2) validate the feasibility of this multipurpose catheter; and (3) study the characteristics of cardiac evoked fields. A stimulation catheter specially designed to produce no magnetic disturbances was inserted into the heart of five patients after routine electrophysiological studies. The catheter position was documented on biplane cine x‐ray images. MCG signals were then recorded in a magnetically shielded room during cardiac pacing. Noninvasive localization of the catheter's tip and stimulated depolarization was computed from measured MCG data using a moving equivalent current‐dipole source in patient‐specific boundary element torso models. In all five patients, the MCG localizations were anatomically in good agreement with the catheter positions defined from the x‐ray images. The mean distance between the position of the tip of the catheter defined from x‐ray fluoroscopy and the MCG localization was 11 ± 4 mm. The mean three‐dimensional difference between the MCG localization at the peak stimulus and the MCG localization, during the ventricular evoked response about 3 ms later, was 4 ± 1 mm calculated from signal‐averaged data. The 95% confidence interval of beat‐to‐beat localization of the tip of the stimulation catheter from ten consecutive beats in the patients was 4 ± 2 mm. The propagation velocity of the equivalent current dipole between 5 and 10 ms after the peak stimulus was 0.9 ± 0.2 m/s. The results show that the use of the amagnetic catheter is technically feasible and reliable in clinical studies. The accurate three‐dimensional localization of this multipurpose catheter by multichannel MCG suggests that the method could be developed toward a useful clinical tool during electrophysiological studies.
Five‐Year Follow‐Up of a Bipolar Steroid‐Eluting Ventricular Pacing Lead
Authors: SCHWAAB BERNHARD , FRÖHLIG GERD , BERG MONIKA , SCHWERDT HOLGER , SCHIEFFER HERMANN
Published: July 2006

Steroid‐eluting pacing leads are known to attenuate the threshold peaking early after implantation. Long‐term performance, however, is not yet settled. The lead design tested in this prospective study combines a 5.8‐mm2 tip of microporous platinum‐iridium with elution of 1.0 mg of dexamethasone sodium phosphate and tines for passive fixation (model 5024, Medtronic Inc.). In 50 patients (mean age 69 ± 10 years), the electrode was implanted in the right ventricular apex. Follow‐up was performed on days 0, 2, 5, 10, 28, 90, 180 and every 6 months thereafter for 5‐years postimplant. At each visit, pacing thresholds were determined as pulse duration (ms) at 1.0 V and as the minimum charge (μC) delivered for capture. Lead impedance (Ω) was telemetered at 2.5 V‐0.50 ms, and sensing thresholds (mV) were measured in triplicate using the automatic sensing threshold algorithm of the pacemaker implanted (model 294–03, Intermedics Inc.). On the day of implantation, mean values were 0.10 ± 0.03 ms, 0.12 ± 0.03 μC, 758 ± 131 Ω, and 13.1 ± 1.8 mV, respectively. Beyond 1‐year postimplant, pacing thresholds did not vary significantly. Sensing thresholds and lead impedance values were stable during long‐term follow‐up. Five years after implantation, mean values were 0.23 ± 0.11 ms, 0.24 ± 0.07 μC, 670 ± 139 Ω, and 11.6 ± 3.1 mV for pulse width and charge threshold, lead impedance, and sensing threshold, respectively, and all leads captured at 1.0 V with the longest pulse duration available (1.50 ms). It is concluded that the bipolar steroid‐eluting tined ventricular lead showed stable stimulation thresholds, lead impedance values, and sensing thresholds for 5 years after implantation.
Dynamic Beat‐to‐Beat QT‐RR Relationship During Physiotherapy Effort in Elderly Patients Without Primary Heart Disease
Authors: ARAD MARINA , ABBOUD SHIMON , RADAI MICHAL M. , ELION ORIT , BAR‐NACHUM SHARON , ZOHAR MORE , ADUNSKY ABRAHAM
Published: July 2006

The ECGs from 18 patients hospitalized in a rehabilitation setting, following surgery for hip fracture, were examined to characterize the dynamic behavior of uncorrected QT interval in relation to changing RR interval during physiotherapy effort. ECG waveforms were analyzed to extract beat‐to‐beat QT and RR intervals using a computerized ECG Analyzer (CEA‐1100). The method of defining the QT and RR intervals is based on performing multiple cross‐correlations that enable rejection of artifacts from the analysis. The relationship between the RR and QT intervals was found using the following general formula QTi= cRRbi ‐ 1. Linear regression was performed on the logarithms of QT and RR measurements obtained to estimate the constant (a = log c) and the slope (b) values, reflecting the dynamic change of QT during physiotherapy effort. Having these two values, the dynamic QT extrapolated to a heart period of 1 second (QTcd) was calculated. The results were compared to the conventional corrected static QT according to the Bazzet formula (QTcs). The mean values of constants (a = log c) and slopes (b) over all patients were found to be 1.61 ± 0.23 and 0.33 ± 0.08, respectively, giving a QT (ms) heart‐period (ms) dynamic relation of QTi= 41 × RRi‐10.33. The correlation between the dynamic QT and the static QT intervals was not significant. The mean values of the QTcd and QTcs intervals were significantly different (392 ± 25 ms vs 434 ± 28 ms; P < 0.0001). This dynamic measurement method of QT intervals may provide additional information on normal and abnormal cardiac repolarization in health and disease, helping in the diagnosis of cardiac disorders and arrhythmia risk.
Ibutilide for Termination of Atrial Fibrillation in the Wolff‐Parkinson‐White Syndrome
Authors: VARRIALE PHILIP , SEDIGHI ABDOLLAH , MIRZAIETEHRANE MADJID
Published: July 2006

Ibutilide promptly restored sinus rhythm on two occasions in an elderly patient with AF and rapid ventricular response associated with the WPW syndrome. As a selective Class III antiarrhythmic agent that prolongs cardiac refractoriness, ibutilide offers an alternative effective therapy for rapid termination of AF in WPW.
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.
Incidence and Significance of Chronotropic Incompetence in Patients with Indications for Primary Pacemaker Implantation or Pacemaker Replacement
Authors: LUKL JAN , DOUPAL VLASTIMIL , SOVOVÁ ELIŠKA , LUBĚNA LADISLAV
Published: July 2006

This prospective study was undertaken to evaluate the incidence and significance of chronotropic incompetence in 211 patients [age 71.1 6 10.6 years (mean 6 SD)] by means of maximum exercise test in order to determine the indication for rate‐responsive pacing before primary pacemaker implantation (147 patients) or pacemaker replacement (64 patients). There were 112 (53%) patients with second‐ or third‐degree AV block, 63 (30%) with sick sinus syndrome, and 36 (17%) with chronic atrial fibrillation. Chronotropic incompetence was defined as maximum heart rate lower than age‐adjusted norm calculated by the formula: 0.7 ± (220 – age) and its significance as the difference between the two rates. The overall incidence of chronotropic incompetence was 42%. The incidence was significantly higher in patients with atrial fibrillation (67%, P < 0.0005) and sick sinus syndrome (49%, P < 0.012) than in those with AV block (30%). The mean difference between maximum heart rate and the age‐adjusted norm was 18% (range 2%–63%). The mean difference was significantly higher in patients with atrial fibrillation (27%, range 8–63%) than in those with sick sinus syndrome (19%, range 2%–45%, P < 0.01), or with AV block (12%, range 6%–26%, P < 0.000001). The rate‐responsive pacemakers were implanted in 44% of 211 patients studied and in 43% of 196 patients excluded from the study due to the apparent (contra)indication of rate‐responsive pacing (NS). Thus, chronotropic incompetence seems to be common in the pacemaker patient population. The highest incidence and significance was found in patients with chronic atrial fibrillation. Systematic evaluation of chronotropic competence can double the rate of implantation of rate‐responsive pacemakers; however, further studies are needed to clarify relation between the significance of chronotropic incompetence and functional benefit of rate‐responsive pacing.
Usefulness of Intravenous Propofol Anesthesia for Radiofrequency Catheter Ablation in Patients with Tachyarrhythmias: Infeasibility for Pediatric Patients with Ectopic Atrial Tachycardia
Authors: LAI LING‐PING , LIN JIUNN‐LEE , WU MEI‐HWAN , WANG MING‐JIUH , HUANG CHI‐HSIANG , YEH HUEI‐MING , TSENG YUNG‐ZU , LIEN WEN‐PIN , HUANG SHOEI K. STEPHEN
Published: July 2006

General anesthesia is sometimes required during radiofrequency catheter ablation (RFCA) of various tachyarrhythmias because of an anticipated prolonged procedure and the need to ensure stability during critical ablation. In this study, we examine the feasibility of using propofol anesthesia for RFCA procedure. There were 150 patients (78 male, 72 female; mean age 30 years, range 4–96 years) in the study. Electro physiologic study was performed before and during propofol infusion in the initial 20 patients and was performed only during propofol infusion in the remaining 130 patients. In the initial 20 patients, propofol infusion increased the sinus rate and facilitated AV nodal conduction. The accessory pathway effective refractory period, as well as the sinus node recovery time, atrial effective refractory period, and ventricular effective refractory period were not significantly changed. There were 152 tachyarrhythmias in 150 patients (24 atrial flutter, 31 AV nodal reentrant tachycardia, 68 AV reciprocating tachycardia, 12 ventricular tachycardia, and 17 atrial tachycardia). Most (148/152) tachycardias remained inducible after anesthesia and RFCA was performed uneventfully. However, in four of the seven pediatric patients with ectopic atrial tachycardia, the tachycardia terminated after propofol infusion and could not be induced by isoproterenol infusion. Consequently, RFCA could not be performed. Intravenous propofol anesthesia is feasible during RFCA for most tachyarrhythmias except for ectopic atrial tachycardia in children
Supraventricular Electrical Interaction in Conjoined Twins with Common Coronary Sinus
Authors: HORNUNG TIM S. , SHOLLER GARY F. , LAU KAI C.
Published: July 2006

Conjoined twins with echocardiographic evidence of continuity of the coronary sinuses had identical heart rates on ECG. Both had broad, polyphasic QRS complexes, and various imaging modalities were unable to determine whether there was ventricular myocardial continuity. Administration of adenosine demonstrated that the broad polyphasic complexes were a “fusion” of the twins' individual QRS complexes, which could be clearly distinguished after administration of the drug. Ventricular pacing resulted in dissociation of the individual QRS complexes, thus demonstrating an absence of ventricular myocardial continuity. This was confirmed when the twins were successfully separated at the age of 10 months.
Low Voltage Direct Current Delivered Through Unipolar Transvenous Leads: An Alternate Method for the Induction of Ventricnlar Fibrillation
Authors: EULER DAVID E. , WHITMAN TERESA A. , ROBERTS PAUL R. , KALLOK MICHAEL J.
Published: July 2006

The induction of VF during testing of an ICD may not always he possible using either hurst pacing or high energy T wave shocks. The purpose of this study was to evaluate the effectiveness of low energy DC stimulation for inducing VF in a porcine model. The VFT was measured using constant voltage stimuli and a step‐up method in ten anesthetized pigs (25–30 kg). Stimuli of different durations (0.5, 1.0, 2.0 s) were delivered (unsynchronized) between a right ventricular apical coil and a subcutaneous test can. Current was measured from the voltage drop across a series resistor (10 Ω). With anodal stimulation, VF required 6.4 ± 0.2 V compared to 13.8 ± 0.6 V with cathodal stimulation (P < 0.001). The current required to induce VF (measured 10 ms after the stimulus onset) was 58.3 ± 2.2 mA with anodal stimulation and 119.3 ± 4.7 mA with cathodal stimulation (P < 0.001). Stimulus duration did not significantly influence the voltage or current required for VF induction. In 6 of the 10 pigs, synchronizing a 0.5‐second stimulus to the R wave did not significantly alter the VFT compared to same stimulus synchronized to mid‐upslope of the T wave. The results indicate that VF can he consistently induced through transvenous electrodes hy passing unsynchronized DC for 0.5–2 seconds. The induction of VF required about 50% less current and voltage with anodal stimulation. It should be possible to induce VF with the DC voltage available from the internal hattery source of an ICD.
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.
Heterotrophic nitrification in add forest soils
Authors: Johnsrud Susanna Christl
Published: July 2006

Ninety cultures of heterotrophic organisms were isolated from soils of four acid Norwegian forest sites, which were active in nitrifying. The isolates were tested for ability to form nitrite in a glucose‐ammonium‐inorganic salts medium. Eleven cultures were found capable of oxidizing ammonium to nitrite. The nitrifying organisms consist of 4 bacteria and 7 fungi.
Soil microfungi in three Swedish coniferous forests
Authors: Söderström Bengt E. , Bååth Erland
Published: July 2006

Microfungi were isolated with the soil washing technique from five different soil horizons in three podzolic coniferous forests in Sweden. Totally 126 species were identified of which 45 were found at two and 24 were found at three sites. The most common genera were Mortierella and Penicillium. Other genera isolated in high frequences were Oidiodendron, Tolypocladium, Trichoderma and Verticillium. Pronounced differences in species composition were found between the soil layers, while great similarities were shown in identical soil layers at different sites.
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.
The distribution of Cd, Cu, Pb and Zn in the biota of two freshwater sites with different trace metal inputs
Authors: Anderson R. V. , Vinikour W. S. , Brower J. E.
Published: July 2006

The concentrations of Cd, Cu, Pb, and Zn were determined in the abiotic and biotic components at two sites in the Fox River, Illinois. Analysis of the metals was completed on solutions of wet ashed or dry ashed samples with a single beam atomic absorption spectrophotometer. Despite different inputs of the trace metals there were no significant differences in the concentration of Cu or Zn in the biota between the two sites. This was postulated to be due to physiological control of these metals. However, Cd and Pb concentrations were higher in the biota and substrate at the high input site. No accumulation of Cd or Pb occurred at higher trophic levels. Cu and Zn concentrations were similar for all biota with the exception of crayfish and snails which had higher Cu and Zn concentrations, respectively.
Litter decomposition by slugs in mixed deciduous woodland
Authors: Jennings T. J. , Barkham J. P.
Published: July 2006

For the one year period considered, it is calculated that 683.5 g m‐2 plant litter entered the study area site. Of the six slugs studied, Arion intermedius Normand, the smallest species, had the highest overall consumption rate on the nine test foods (29.1 ± 0.9 mg dry wt g live wt‐1 d‐1) and the highest overall mean assimilation efficiency (72.0 + 0.9%). The mean faecal production for each of the six slug species was very similar, ranging from 8.4 to 9.9 mg dry wt g live wt‐1 d‐1. Using regression equations of food consumed on faeces produced, it is estimated that the slug fauna each year consumes 8.4% of the leaf litter input and 6.5% of the total available plant litter. Of the plant material consumed, 13.8 g dry wt m‐2 are deposited annually as faeces. The role of slugs in decomposition processes is discussed and compared with that of other soil organisms.
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.
Reproduction in the European hare in southern Sweden
Authors: Frylestam Bo
Published: July 2006

Reproduction in the European hare Lepus europaeus Pallas populations was studied in three study areas in South Sweden during 1974–1976; two on the mainland and the third on the Island of Ven in Öresund. The monthly birth rates was calculated on the basis of the age of juvenile hares shot in autumn. The first births always occurred in February, indicating that the onset of the breeding season was governed by day length rather than by climate. Later, the reproduction rate was determined by temperature, snow cover, and precipitation. Low temperatures in spring delayed the reproduction; high temperatures in autumn favoured a prolongation of the breeding season. Low precipitation in May‐July caused a decline in reproduction in July in a sandy pasture area, mainly because water amount was low in the green forage. Annual fertility, estimated on the basis of placental scars, varied between 6.8 and 8.9 young per female. There was a significant negative correlation between fertility and population density. The largest variations were recorded in one‐year‐old females, and on average the values were significantly higher in three‐year‐old females. 68% of all females examined had three litters annually; four litters were found in only 13% of all females. The mean litter size for the whole period was about 2.9 in all areas. The size of the first litter was significantly higher in females producing one or two litters than in females with three or four litters. The postnatal losses were on average 30–35% lower in the island population than in the mainland populations (73–84%), probably due to lack of predators, sparse road traffic, and inhibited juvenile dispersal.
Effects of weather on foraging‐flights of bumblebees (Hymenoptera, Apidae) in a subalpine/alpine area
Authors: Lundberg Hans
Published: July 2006

The foraging activity of bumblebees in a subalpine/alpine area in northern Sweden was related to weather factors (temperature, light, wind and rain) by counting the number of specimens visiting a square (5 × 5 m) with a high density of forage plants. The combined effect of light and temperature was the most important factor regulating the flight activity. The condition of the arctic light‐climate allows bumblebees to fly even at the less light hours of the day. No clear differences according to flight activity were observed between the subalpine/alpine species Bombus balteatus Dahlbom, B. lapponicus (Fabricius) and the species B. jonellus (Kirby), B. pascuorum (Scopoli), B. pratorum (L.), observed in the subalpine habitats. A comparison between the flight activity of queens, workers and males shows that queens are able to fly at the lowest temperatures followed by males and workers at slightly higher temperatures. The relevance of the overlap of the body sizes between the casts is discussed.
Niche differentiation between two littoral prawns in Gullmar Fjord, Sweden: Palaemon adspersus and P. squilla
Authors: Berglund Anders
Published: July 2006

Palaemon squilla (L.) at the Swedish west coast occurred on bottoms covered with Zostera marina L., on bare sand bottoms, in moving water and in rock pools, while P. adspersus Rathke was found on Zostera covered bottoms only. During summer 1978 the increase in length of P. adspersus was 2.2 times greater than that of P. squilla, the former species also attaining a larger maximal size. Laboratory studies showed a wide tolerance in both species to combinations of temperature and salinity. P. squilla tolerated higher temperatures than P. adspersus. The locomotory activity of P. squilla was more than twice that of P. adspersus and concentrated to the dark period. Stomach analyses revealed no interspecific differences in food selection. P. squilla appears to be an opportunistic species able to survive in many different habitats, with a higher dispersal ability, smaller size and larger tolerance to extreme values of abiotic parameters, while P. adspersus is a K‐strategist with a high competitive ability, a larger proportion of availably energy devoted to growth, and with larger body size and lower mobility. Although these differences enable the two species to coexist in certain habitats, their habitat segregation still appears to be of primary importance to reduce competition between them.
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.
Changes in the diatom microflora of a eutrophic lake since 1900 from a comparison of old algal samples and the sedimentary record
Authors: Battarbee Richard W.
Published: July 2006

Diatoms in a series of old plankton samples collected from Växjösjön, southern Sweden, between 1912 and 1971 were compared to the planktonic diatom record of the sediment accumulated during the same period. Contemporary descriptions of the floristic composition of the various samples were found to be unreliable. Clear taxonomic discrepancies between the written records and the sediment record necessitated the re‐examination of all old samples and the adoption of a standardised taxonomy. When compared on this basis changes through time in the composition of the diatoms in the old samples were found to be in close agreement with changes recorded in the sediment. The re‐emergence of Melosira italica subsp. subarctica in the mid 1940's, probably as a result of the partial improvement in the lake following sewage diversion, is seen clearly in both sets of data. The importance of storing algal samples for use in future palaeoecological research is stressed.
Winter decline of spiders and insects in spruce Picea abies and its relation to predation by birds
Authors: Jansson Christer , von Brömssen Anders
Published: July 2006

Insects and spiders were sampled on branches of spruce in a 5.5 km2 area before and after each of six winters. Psocoptera, Aphidoidea and Lepidoptera larvae were the most common insects in autumn. In Feb–Mar only 1% remained, most of the decline occurring already early in the winter. Spiders were almost as common as Psocoptera in autumn but survived winter to 28–45%. Spiders therefore are potentially more important food for wintering birds than are insects. Through the first five winters there was a steady increase in density of small (but not large) spiders both in autumn (290%) and spring (390%). Spring densities of small but not large spiders were significantly correlated to autumn densities. Usually there was no added variability of spider abundance between trees and most of the variability was found within trees. In autumn spiders occurred at significantly higher densities in the lower half of the spruce trees than in the upper half. Much of the reduction of large spiders over winter is known to be caused by predation by birds. Over winter, this predation probably makes the distribution of spiders within trees more uniform. The autumn density of three tit species, the goldcrest and the treecreeper was significantly correlated with the density of large spiders at the same time, but not with small spiders (which they presumably do not eat). This might be caused by territorial behaviour being related to food density in autumn.
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.
Overwintering of benthic macroinvertebrates in ice and frozen sediment in a North Swedish river
Authors: Olsson Tommv I.
Published: July 2006

In winter the water freezes into the substrate within considerable areas of unregulated northern rivers due to low temperature combined with a lowering of the water level. Living individuals of Nematoda, Gastropoda, Sphaeriidae, Oligochaeta, Hirudinea, Isopoda, Trichoptera and Chironomidae were found in samples of ice and frozen sediment from the bottom frozen hydrolittoral zone of the north Swedish river Vindelälven. All abundant species in the frozen substratum, except Asellus aquaticus, seemed to be well adapted to withstand overwintering in this special habitat free from predation. Generally, between 80 and l00% of enclosed animals survived thawing. Cysts or other kinds of resting stage constructions, similar to those found during drought, were common in several enclosed species. Specimens of Gyraulus acronicus, Pisidium ssp., Molanna albicans and Chironomidae survived exposure to −4°C for five month in a freezing experiment. Extracellular freezing of the invertebrates overwintering in the ice is probable, as the ambient temperature was below the true freezing point of most animals. The composition of the substratum may effect the survival of animals enclosed in ice.
Biology of the minnow Phoxinus phoxinus and its interactions with brown trout Salmo trutta in Øvre Heimdalsvatn, Norway
Authors: Lien Leif
Published: July 2006

Minnows have recently been introduced into the mountain lakes of southern Norway. In Øvre Heimdalsvatn, an intensively studied lake, the minnow population has increased rapidly during the last decade. Studies were performed on feeding habits, habitat preferences, age, growth, energy content, densities, parasites, predation and spawning activities. Several aspects were found to be different from other studies, e.g. higher age of sexual maturation, lower growth rate, no feeding on plants, and low infection of parasites. The interaction with the only other fish, the brown trout, is discussed in relation to the minnow population. In 1978 the minnows constituted little more than 10% of production and food consumption of the trout population, and only limited food competition and predation was documented. Increasing competition is likely with a greater minnow population.
Hoarding of individual nuthatches Sitta europaea and march tits Parus palustris
Authors: Moreno Juan , Lundberg Arne , Carlson Allan
Published: July 2006

The hoarding behaviour of one pair of nuthatches Sitta europaea L. and of four individual marsh tits Parus palustris L. was studied during autumn and winter in a deciduous grove in central Sweden. Sunflower seeds were offered at a feeding table. AM individuals studied stored seeds intensively throughout the whole study period. The two species showed very different hoarding patterns. The nuthatch pair aggressively defended the area around the feeding table, which was within their territory, from other nuthatches and also seemed to affect the hoarding behaviour of the coexisting marsh tits. Some significant differences were found also between con‐specifics in some aspects of hoarding behaviour, which could in some cases be related to sex or dominance. These differences may make hoarding profitable for the individual birds if they also differ in their foraging patterns individually, and so will have a greater probability of finding their own stored items than other individuals. However, the evidence for individual segregation of hoarding patterns is not conclusive.