bluuebunny/crossref_metadata_2025_split huggingface dataset:
Habitat selection by breeding Curlews Nwnenius arquata on mosaic farmland
Authors: BERG ÅKe 
Published: April 2008

Territory establishment and habitat use by breeding Curlews Numenius arquata were studied during 1987 and 1988 on mosaic farmland (dominated by dry tillage) at two sites in central Sweden. Curlews preferred to breed in areas with a high proportion of grassland, close to rivers, while dry tillage was avoided. Territories at my study site were larger (mean = 4 5.2 ha) than in areas consisting entirely of grassland. Territory size seemed to depend on the spatial distribution of grasslands, which suggests that habitat fragmentation forces Curlews to establish larger territories in modern farmland than in areas of grassland. The number of territories in patches of grassland was correlated with patch area, and unoccupied patches were more isolated than occupied patches. However, patch area was a more important factor than isolation, since large patches (> 3 5 ha) were always occupied. Sown grassland was used significantly more than expected for foraging early in the season, possibly indicating the strong influence of the nutritional requirements in the pre‐breeding period on territory establishment. Habitat selection when foraging seemed to be less important late in the season, since there was no significant habitat preference then. During this period distance to the nest site seemed to be more important than habitat, sinced the preferred foraging fields (including fields of all habitats used more than expected by area) were situated closer to nests than the less preferred fields, probably an adaptation to the high nest predation risk. The same fields were mostly preferred in the pre‐breeding period also, suggesting that nests were built close to good foraging areas.My results indicate that the decline of the Swedish Curlew population since 1950 is caused by changes in land use, resulting in decreased grassland area and increased habitat fragmentation, which probably have affected both breeding and foraging possibilities negatively.
Effects of supplementary food on density‐reduced breeding in an African eagle: adaptive restraint or ecological constraint?
Authors: SIMMONS ROBERT E. 
Published: April 2008

Increased population density often reduces reproductive output in breeding birds, but the underlying mechanisms (adaptive restraint v reduced food resources) behind decreased productivity are poorly understood. Here I correlatively and experimentally investigated the roles of food, breeding density, latitude, altitude and rainfall in limiting productivity of Wahlberg's Eagles Aquila wahlbergi throughout Africa. Breeding success in equatorial and subtropical Africa (0°–30°S) was highly density‐dependent but showed no latitudinal or rainfall‐related trends. Pairs in dense populations produced half as many young annually as pairs in low‐density populations. Density (but not rainfall or latitude) also explained much of the geographic variation in the mean proportion of pairs attempting to breed each year and the incidence of two‐egg clutches.Breeding within populations was consistent with these density‐dependent trends: incidence of two‐egg clutches increased in a declining population, and productivity was inversely related to breeding density and rainfall combined. To determine if reduced food resources accounted for reduced output in dense populations, eight pairs were food supplemented: supplementary food failed to induce nonbreeding pairs to breed: nor did it induce earlier laying or increase egg size or clutch‐size. Population density itself was unrelated to two correlates of food resources, rainfall and latitude. I conclude that population density influences most aspects of breeding in Wahlberg's Eagles, and reduced food resources do not appear to explain these trends. Hence, adaptive restraint may account for decreased annual reproduction in this species.
Annual survival of Sparrowhawks Accipiter nisus breeding in three areas of Britain
Authors: NEWTON I. , WYLLIE I. , ROTHERY P. 
Published: April 2008

Annual survival of breeding female Sparrowhawks Accipiter nisus was estimated by a capture‐recapture procedure in three different areas, Eskdale and Annandale in southern Scotland and Rockingham Forest in east‐central England.In Eskdale, where the breeding population remained fairly stable during a 19‐year study, annual survival averaged 59% (s.e. = 4%). In Annandale, where the breeding population declined during a 10‐year study, annual survival averaged 66% (s.e. = 4%). In Rockingham, where the breeding population increased during an 11‐year study, annual survival averaged 72% (s.e. = 4%). In this area, survival declined during the study as numbers rose. The apparent density‐dependence in survival was therefore confounded with a time trend.In all three areas, annual variations in survival were negatively related to the number of rain days during October‐April, but the relationship was significant only in Eskdale. This area had the longest run of data and the greatest variation in the number of winter rain days. The relationship with rain days could partly account for the differences in mean survival between areas, with lowest survival in the wettest area and highest survival in the driest.
Effects of habitat fragmentation on the timing of Crested Tit Parus cristatus natal dispersal
Authors: LENS LUC , DHONDT ANDRE A. 
Published: April 2008

Crested Tit Parus cristatus young from first broods dispersed 1 week later if they were born in small isolated pine plots (‘habitat fragments’) compared with individuals in a large pine forest (‘continuous habitat’). This delay in dispersal was caused by an extended period between fledging and dispersal. In second broods, the delay was even longer due to the interbrood interval being 9 days longer in habitat fragments. As nestlings in habitat fragments had a lower body‐mass, and age at dispersal was negatively correlated with nestling body‐mass within each nest, the postponed dispersal from fragments might be explained partly by a lower body‐mass. Alternatively, postponed dispersal from fragments could result from a barrier effect caused by reluctance to cross inhospitable habitat.Immigration by young from first broods into habitat fragments was delayed by approximately 3 weeks, and proportionally more second brood emigrants were recovered in this type of habitat. These results are in agreement with the hypothesis that fragments are second‐choice habitat. Early immigrants into continuous habitat had a higher probability of settlement in winter flocks compared with late ones, independent of condition or age. Therefore, Crested Tits born in habitat fragments probably have a lower chance of settling in first‐choice habitat.
Family break‐up in Black and Red Kites Milvus migrans and M. milvus: is time of independence an offspring decision?
Authors: BUSTAMANTE* JAVIER 
Published: April 2008

I observed the natural process of family break‐up in 13 families of Black Kites Milvus migrans and five families of Red Kites M. milvus in which fledglings had been individually marked. In other broods, I performed experiments which modified the parental investment fledglings received by supplementing nests of both species with food or transferring Black Kite chicks to nests with younger or older chicks of the same species.The time of family break‐up in the Black Kite is mainly an offspring decision which is not affected by an artificial increase of parental investment. The duration of the post‐fledging period was not increased in Black Kites that were given supplementary food. Chicks transferred to nests with a younger chick did not extend the post‐fledging period, nor did chicks transferred to nests with an older chick shorten the post‐fledging period. In Red Kites, parental investment seemed to have more influence on the timing of the family break‐up. Red Kite adults invested less as parents than did Black Kites during the post‐fledging dependence period, and in nests where supplementary food was given, Red Kite fledglings stayed attached for a longer period.
Distribution of shorebirds at the Berg River estuary, South Africa, in relation to foraging mode, food supply and environmental features
Authors: KALEJTA B. , HOCKEY P.A.R. 
Published: April 2008

Foraging densities of Curlew Sandpipers Calidris ferruginea and Grey Plovers Pluvialis squa‐tarola at the Berg River estuary, South Africa, are examined in relation to prey and habitat attributes.There is a substantial overlap in the prey species eaten by Curlew Sandpipers and Grey Plovers, but the distribution patterns of the two species within the estuary could not be explained by the same prey attributes.The distribution of tactilely foraging Curlew Sandpipers was determined largely by the numerical abundance of nereid worms. They foraged preferentialiy on muddy rather than sandy substrata, but their distribution could not be explained on the basis of substratum penetrability. The density of visually foraging Grey Plovers was correlated with the biomass, rather than abundance, of the larger of the two common nereids on the estuary. The favoured foraging area of Grey Plovers had a high vegetation cover, but their foraging dispersion was not influenced by substratum type.The energy intake rates of Curlew Sandpipers were broadly inversely related to their foraging density, although the rate of prey capture was maximal at high prey density. These birds may use neighbour success rates in selecting foraging sites. Energy intake rates of Grey Plovers were very consistent across the estuary, suggesting that individuals occupy or defend areas which provide access to comparable food resources.
Intraspecific brood‐parasitism and dispersal in fledgling Sparrowhawks Accipiter nisus
Authors: FRUMKIN RON 
Published: April 2008

The progeny of early‐nesting Sparrowhawks Accipiter nisus have a higher survival rate than those of late nesters. To ascertain the reasons for greater survival in early‐season Sparrowhawk fledglings, I studied post‐fledging dispersal behaviour in this species by direct observations and radio‐tracking during 3 years in Rockingham Forest, Northamptonshire, U.K.Post‐fledging brood‐parasitism was found among early‐dispersed young of both sexes.Early‐dispersed young spent up to 6 days being fed by the parents of other fledged, but still dependent, broods, as far as 6 km from their own nests.Three broods were provided with supplementary food for 4 weeks, starting 1 week before expected dispersal. These young dispersed when significantly older than young from control broods. In both groups, males dispersed, on average, 3–4 days earlier than females. The ultimate dispersal age of young in control broods was negatively correlated with their rate of mass gain during the nestling period. Unlike the young of the control broods, fledglings in broods with augmented food were usually silent.These findings offer an explanation for why Sparrowhawk young that disperse early in the season survive better than those which disperse late.
Pelagic communities of seabirds in the South Atlantic Ocean
Authors: VEIT RICHARD R. 
Published: April 2008

This paper presents quantitative analyses at the community level of the spatial dispersion of 44 species of pelagic birds in the South Atlantic Ocean. I have examined the extent to which assemblages of pelagic bird species are influenced by the combined influences of the abundances of other species and the physical structure of the pelagic environment. Results are based upon strip transects collected from oceanographic research vessels during the four consecutive austral summers of 1982–1986.The distributions of most seabird species were statistically independent of the distributions of other species. Species assemblages, however, did occur and were correlated with the physical structure of the ocean. The study area was divided into four zones, each defined by a distinctive assemblage of birds. Physical oceanography proved to be important in determining the species composition of each zone. These relationships were apparent despite the potentially confounding influence of large numbers of immatures and non‐breeding adults.
Growth, fledging success and post‐fledging survival of juvenile Oystercatchers Haematopus ostralegus
Authors: KERSTEN MARCEL , BRENNINKMEIJER ALEX 
Published: April 2008

We studied the consequences of differences in growth rate on the subsequent survival of Oystercatcher Haematopus ostralegus chicks. Fledging success increased sharply with growth rate, from zero in chicks growing at less than 6 g per day to about 85% in chicks growing at more than 10 g per day. The age at which chicks fledged varied from 27 to 52 days. Chicks which fledged at an early age displayed a much faster growth rate than later fledging chicks. Although slow growth resulted in a considerable prolongation of the period before fledging, slow‐growing chicks fledged at a smaller size and with a lower body‐weight than fast‐growing chicks. After fledging, all chicks remained almost completely dependent on their parents up to an age of 3 months and often longer.Almost 40% of the fledglings eventually returned to the breeding area. This figure probably reflects post‐fledging survival. Age and size at fledging had no effect on a chick's probability of return. Body‐weight at fledging had a small positive correlation with the return probability, but this was not statistically significant. We conclude that although slow growth severely reduces a chick's chance of fledging, it probably does not result in irreversible damage causing an increased risk of mortality during the first years after fledging. Apparently, any possible disadvantage associated with small size or low body‐weight could be compensated for after fledging.
Plant species' response to climate change: implications for the conservation of European birds
Authors: HUNTLEY BRIAN 
Published: April 2008

Wildlife conservation faces new and extreme challenges in adapting to the accelerating dynamics of a world responding to global change. The Quaternary record shows that migration has been the usual response of organisms to environmental change. This record also reveals that forecast future climate changes are of a magnitude and in a direction unprecedented in recent earth history: the rate of these changes is likely also to surpass that of any comparable change during the last 2.4 million years.The relationship between a species' geographical distribution and present climate may be modelled by a surface representing the probability of encountering that species under given combinations of climate conditions. This ‘climate response surface’ then may be used to simulate potential future distributions of the species in response to forecast climate scenarios. Such simulations reveal the magnitude of the impacts of these forecast climate changes. Although to date this approach has been applied in Europe only to plants, it promises to be valuable also for other groups of organisms, including birds. Some bird species, however, may respond more directly to either habitat structure or presence of specific food plants; such factors may be incorporated into the models when required.The magnitude of likely vegetation changes necessitates a global approach to conservation if there is to be any hope of long‐term success. Successful conservation of global biodiversity will depend upon conservation of the global environment and limitation of the human population much more than upon parochial efforts to conserve locally rare organisms or habitats.
Are baroreflex events detected by invasive and non‐invasive techniques coincident?
Authors: Smith Stephen M. , Potter John F. , Samani Nilesh J. , Sammons Emily L. , Rathbone Wendy E. , Bentley Stephen , Panerai Ronney B. 
Published: April 2008

SummaryCardiac baroreceptor sensitivity, a prognostic indicator for a range of diseases, such as myocardial infarction and stroke, may be estimated from spontaneous fluctuations of arterial blood pressure (BP) and heart rate using sequence analysis. We tested the hypothesis that BP values recorded with the non‐invasive Finapres device do not always produce sequences coincident with sequences detected from central BP measurements. Finapres recordings of resting BP in the finger, ascending aorta (Millar catheter‐tip transducer) and ECG were obtained from 34 patients undergoing coronary angioplasty, including 24 patients treated with betablockers. Coincidence of baroreflex sensitivity (BRS) sequences was expressed by the sensitivity of the Finapres to detect a simultaneously occurring sequence in aortic pressure. The influence of different criteria to detect and accept sequences from beat‐to‐beat values of systolic BP (SBP) and cardiac interval (RRi) on the Finapres sensitivity was also assessed. The Finapres was able to detect 70·7% of all three beat intra‐arterial sequences when the selection criteria was based on the correlation coefficient between SBP and RRi (>0·85), but decreased to 27·5% when the P‐value of the linear regression was limited to 0·05. Changing the thresholds for minimum changes in SBP and RRi also had significant effects on sensitivity, as well as in the corresponding values of BRS. Significant differences in BRS were obtained between invasive and non‐invasive estimates, but there was no difference between non‐invasive estimates calculated from coincident and non‐coincident sequences. Non‐invasive, compared with intra‐arterial estimates of BRS by sequence analysis are not influenced by coincidence of sequences if acceptance of sequences is based on the correlation coefficient criteria (>0·85).
Endoscopic Removal of a Bronchial Carcinoma in a Dog Using One‐Lung Ventilation
Authors: MOSING MARTINA , IFF ISABELLE , MOENS YVES 
Published: April 2008

Objective— To describe anesthetic management of endoscopic electrosurgical removal of a bronchial carcinoma, partially blocking the right main stem bronchus in a Cocker Spaniel.Study Design— Clinical case report.Animals— Dog with a bronchial carcinoma.Methods— To allow sufficient space for the endoscope and to avoid an oxygen‐rich gas mixture in the trachea, which carries the risk of an airway fire when electrocautery is used, a 1 lumen endobronchial tube (EBT) was inserted into the left main stem bronchus. One‐lung ventilation (OLV) started with a volume‐controlled ventilator was switched to pressure‐controlled ventilation in combination with positive end‐expiratory pressure (PEEP).Results— Resection of the bronchial carcinoma was successful. The dog was hypercapnic throughout the procedure and a high alveolar‐arterial oxygen gradient was measured.Conclusion— An EBT may be a feasible and safe option to provide OLV for bronchoscopic electrocautery with a closed thoracic cavity in dogs.Clinical Relevance— EBT intubation for OLV should be considered as part of the anesthetic management of airway diseases treated with bronchoscopic electrocautery.
Canine Stifle Positive Contrast Computed Tomography Arthrography for Assessment of Caudal Horn Meniscal Injury: A Cadaver Study
Authors: TIVERS MICHAEL S. , MAHONEY PAUL , CORR SANDRA A. 
Published: April 2008

Objective— To investigate the use of computed tomography (CT) arthrography in cadaveric canine stifles with particular emphasis on the diagnosis of meniscal injury.Study Design— Prospective cadaver study.Sample Population— Pelvic limbs from adult Beagles (n=10).Methods— After survey CT scan of each stifle oriented in the dorsal plane, positive contrast stifle CT arthrogram (CTA) was performed using the same slice orientation. Each stifle was then randomly allocated into 1 of 2 treatment groups: group A—arthrotomy, cranial cruciate ligament (CCL) transection and simulated injury to the caudal horn of the medial meniscus; group B—arthrotomy and CCL transection only. CT scan was repeated as before and post‐arthrotomy images were interpreted by a radiologist unaware of treatment grouping.Results— The cranial and caudal cruciate ligaments, medial and lateral menisci, menisco‐femoral ligament, and long digital extensor tendon were all identifiable on CTA images. CTA was 90% sensitive and 100% specific for diagnosing simulated caudal horn meniscal injury.Conclusions— Stifle CTA enables identification of intra‐articular structures within the stifle and is a reliable method for identifying simulated meniscal injuries in a cadaver model.Clinical Relevance— CTA imaging of the canine stifle has potential clinical value for detection of meniscal injury.
History of hemodialyzers' designs
Authors: TWARDOWSKI Zbylut J. 
Published: April 2008

AbstractAccumulation of knowledge requisite for development of hemodialysis started in antiquity and continued through Middle Ages until the 20th century. Firstly, it was determined that the kidneys produce urine containing toxic substances that accumulate in the body if the kidneys fail to function properly; secondly, it was necessary to discover the process of diffusion and dialysis; thirdly, it was necessary to develop a safe method to prevent clotting in the extracorporeal circulation; and fourthly, it was necessary to develop biocompatible dialyzing membranes. Most of the essential knowledge was acquired by the end of the 19th century. Hemodialysis as a practical means of replacing kidney function started and developed in the 20th century. The original hemodialyzers, using celloidin as a dialyzing membrane and hirudin as an anticoagulant, were used in animal experiments at the beginning of the 20th century, and then there were a few attempts in humans in the 1920s. Rapid progress started with the application of cellophane membranes and heparin as an anticoagulant in the late 1930s and 1940s. The explosion of new dialyzer designs continued in the 1950s and 1960s and ended with the development of capillary dialyzers. Cellophane was replaced by other dialyzing membranes in the 1960s, 1970s, and 1980s. Dialysis solution was originally prepared in the tank from water, electrolytes, and glucose. This solution was recirculated through the dialyzer and back to the tank. In the 1960s, a method of single‐pass dialysis solution preparation and delivery system was designed. A large quantity of dialysis solution was used for a single dialysis. Sorbent systems, using a small volume of regenerated dialysis solution, were developed in the mid 1960s, and continue to be used for home hemodialysis and acute renal failure. At the end of the 20th century, a new closed system, which prepared and delivered ultrapure dialysis solution preparation, was developed. This system also had automatic reuse of lines and dialyzers and prepared the machine for the next dialysis. This was specifically designed for quotidian home hemodialysis. Another system for frequent home hemodialysis or acute renal failure was developed at the turn of the 21st century. This system used premanufactured dialysis solution, delivered to the home or dialysis unit, as is done for peritoneal dialysis.