bluuebunny/crossref_metadata_2025_split huggingface dataset:
The structure and innervation of the male urethra: histological and immunohistochemical studies with three‐dimensional reconstruction
Authors: Karam I. , Moudouni S. , Droupy S. , Abd‐Alsamad I. , Uhl J. F. , Delmas V. 
Published: March 2005

AbstractThe structure of the striated urethral sphincter, the so‐called rhabdosphincter, remains the subject of controversy. There are two main concepts regarding its structure: either it is a part of the urogenital diaphragm, or it extends from the base of the bladder up to the urogenital diaphragm and is an integral part of the urethra. It is also uncertain whether it possesses a somatic innervation or a mixed innervation (i.e. autonomic and somatic). The purpose of this study was to show the precise location of the nerves running to the urethra, and to try to determine their exact nature. Histology and immunohistochemistry were performed in the external urethral sphincter of ten male fetuses (114–342 mm crown–rump length, or between 14 and 40 weeks of gestation). A three‐dimensional (3D) reconstruction of the urethral structure and its innervation was made from serial sections. The 3D reconstruction of the same section levels with different strains allowed us to identify the precise structure of the muscle layers (smooth and striated muscle fibres) and the nature of the nerve elements (myelinated and unmyelinated), their distributions and their relationship to the urethral wall, the prostate and the seminal vesicles. Histological and immunohistochemical 3D reconstruction of the anatomical elements of the urethral sphincter helps us to understand the 3D arrangement of the sphincter muscle layers. It also provides a better understanding of the origin and nature of the nerve elements that play a role in urinary continence.
A new fate for old cells: brush cells and related elements
Authors: Sbarbati A. , Osculati F. 
Published: March 2005

AbstractOver the past 50 years, hundreds of studies have described those cells that are characterized by a brush of rigid apical microvilli with long rootlets, and which are found in the digestive and respiratory apparatuses. These cells have been given names such as brush cells, tuft cells, fibrillovesicular cells, multivesicular cells and caveolated cells. More recently, it has been realized that all these elements may represent a single cell type, probably with a chemosensory role, even if other functions (e.g. secretory or absorptive) seem to be possible. Very recent developments have permitted a partial definition of the chemical code characterizing these elements, revealing the presence of molecules involved in chemoreceptorial cell signalling. A molecular cascade, similar to those characterizing the gustatory epithelium, seems to be present in these elements. These new data suggest that these elements can be considered solitary chemosensory cells with the presence of the apical ‘brush’ as an inconsistent feature. They seem to comprise a diffuse chemosensory system that covers large areas (probably the whole digestive and respiratory apparatuses) with analogies to chemosensory systems described in aquatic vertebrates.
Differences in egg size, shell thickness, pore density, pore diameter and water vapour conductance between first and second eggs of Snares Penguins Eudyptes robustus and their influence on hatching asynchrony
Authors: MASSARO MELANIE , DAVIS LLOYD S. 
Published: March 2005

Brood reduction in birds is frequently induced by hatching asynchrony. Crested penguins (genus Eudyptes) are obligate brood reducers, but in contrast to most other birds, first‐laid eggs are considerably smaller in size than second‐laid eggs; furthermore, first‐laid eggs hatch after their siblings. The mechanisms underlying this reversal in size and hatching order remain unclear. In this study, we tested whether the second‐laid eggs of Snares Penguins Eudyptes robustus have a higher eggshell porosity allowing them to maintain a higher metabolic rate throughout incubation and to hatch before their first‐laid siblings. We investigated differences in egg size, shell thickness, pore density, pore diameter and water vapour conductance between first and second eggs within clutches and examined the influence of these shell characteristics on hatching asynchrony. First‐laid eggs of Snares Penguins were approximately 78% of the size of the larger second eggs. Second‐laid eggs had considerably thicker shells and more pores per cm2 than first eggs, whereas pore diameter did not differ between eggs. Water vapour conductance was greater in second‐ (16.8 mg/day/torr) than in first‐laid eggs (14.9 mg/day/torr). The difference in water vapour conductance between first‐ and second‐laid eggs within clutches was related to hatching patterns. In nests where second eggs hatched before first‐laid eggs, second eggs had a considerably greater water conductance than their sibling, whereas in nests where both eggs hatched on the same day, the difference in water conductance between eggs was very small, and in a few nests where small first eggs hatched before their larger sibling, they had a greater water conductance than their larger second‐laid nestmate. Surprisingly few studies have investigated differences in shell characteristics between eggs within clutches and associated effects on hatching asynchrony. This study has demonstrated that such differences exist between eggs within clutches and that they can influence hatching patterns.
Changes in the timing of spring and autumn migration in North American migrant passerines during a period of global warming
Authors: MILLS ALEXANDER M. 
Published: March 2005

Butler (2003)used first arrival dates (FADs) of 103 migrant birds in northeastern USA and found that both long‐distance migrants (LDMs; wintering south of the USA) and short‐distance migrants (SDMs; wintering in the southern USA) arrived earlier in the second half of the 20th century than they had in the first, consistent with scenarios of global warming; the trend was stronger in SDMs. Using FADs to characterize migration systems can be problematic because they are data from one tail of a distribution, they comprise a mostly male population and they may not correlate well with the balance of the migration period. FADs also provide no information about autumn migration. This paper uses a banding dataset from Long Point Bird Observatory, Ontario, for 14 passerines for a period of global warming (1975–2000), taking these issues into account. The data were filtered to minimize effects of unequal netting effort (147 491 resulting records), and the passage dates then calculated in each season of each year for the 1st, 2nd and 3rd quartiles for regression analysis. Only two of 13 species analysed in the spring showed significantly earlier passage times, although the overall trend was towards earlier spring migration, especially among SDMs. Autumn responses were more prevalent, however, and in some cases more dramatic with six of 13 species showing delayed migration (four SDMs, two LDMs). Two LDMs exhibited earlier autumn migration. Where earlier spring migration occurred, both sexes appeared to contribute to the change. Where delayed migration occurred in autumn, both sexes and both adults and hatch‐year birds appeared to contribute in at least some cases. The spring FAD results are consistent with those of Butler, but when the whole migration is considered, change is far from universal in spring and is in fact more substantial and complex in autumn.
The scaling of primary flight feather length and mass in relation to wing shape, function and habitat
Authors: DAWSON ALISTAIR 
Published: March 2005

The mass and length of each primary flight feather was measured in 120 species of birds (347 individuals) representing 37 families and 15 orders. The scaling relationship between mass and length was determined using the mass of each primary as a proportion of total primary feather mass for that individual and, similarly, length as a proportion of total length. This eliminated errors due to intra‐ and interspecific differences in absolute size. In every species there was a highly significant constant scaling relationship (log mass/log length) for all of the primary feathers proximal to the feather that formed the wing tip. This relationship was allometric and varied between 1.80 in Rooks Corvus frugilegus and 4.87 in Winter Wrens Troglodytes troglodytes. The mean scaling relationship for 120 species was 2.41 ± 0.42 sd, which was significantly less (P < 0.0001) than isometry (i.e. 3.00). In most species (117 of 120) the primary feather forming the wing tip and all feathers distal to it had a different scaling relationship, and had a greater mass than expected from their length. The greater relative mass of the outer primaries may reflect a protective role against physical abrasion, or an aerodynamic role in that each of these feathers provides a leading edge to the wing. Thus, there were two scaling relationships that pivoted about the feather forming the wing tip, resulting in a characteristic ‘signature’ for each species. Scaling relationships can be related to flight characteristics and habitat, rather than to phylogeny. Closely related species often had widely varying scaling relationships. In general, species exploiting dense vegetation had greater scaling relationships than more aerial species. However, species with a high scaling relationship did not have a greater mean feather mass, so the increased relative mass of the distal primaries was at the expense of proximal primary feather mass.
Temporary flightlessness in pre‐laying Common Eiders Somateria mollissima: are females constrained by excessive wing‐loading or by minimal flight muscle ratio?
Authors: GUILLEMETTE MAGELLA , OUELLET JEAN‐FRANÇOIS 
Published: March 2005

Large body size, small wings and relatively low flight muscle mass are general attributes of flightlessness in birds, but a general analysis is lacking when considering these factors simultaneously. Common Eiders Somateria mollissima are large sea ducks characterized by short, pointed wings of low surface area. Because females fast throughout incubation, they need to accumulate large body reserves prior to laying. During this pre‐laying period, many females cannot take off, and dive when approached under still‐air conditions, whereas males take off readily when disturbed. In this paper, we examine how pre‐laying female Common Eiders fit the maximum wing‐loading ratio of Meunier, the marginal flight muscle ratio (FMR) of Marden and predictions of a general model of take‐off performance (also by Marden). Wing morphology was recorded and flight muscles were dissected from specimens collected during the pre‐laying period near one breeding colony. In addition, take‐off ability, as observed during collection, was compared with the proposed thresholds for flightlessness and outputs from the general model of take‐off performance. The results indicated that half of the pre‐laying females exceeded the wing‐loading ratio of Meunier, although all females had values above 0.160, the flight muscle ratio below which take‐off would be impossible. We suggest that wing‐loading and flight muscle ratio interact in Eiders, with higher FMR compensating for excessive wing‐loading. Nevertheless, the model of take‐off performance predicted, with reasonable accuracy, the behavioural observations under still‐air conditions. Indeed, females that were predicted to be temporarily flightless could produce a specific lift of 8.8 N/kg on average (less than the 9.8 N/kg required to overcome gravity). In contrast, the average specific lift predicted for males capable of flight was estimated to be 11.4 N/kg. These results agree with our observations that female Common Eiders are at the limit of flight capability in vertebrates.
Temporary flightlessness as a potential cost of reproduction in pre‐laying Common EidersSomateria mollissima
Authors: GUILLEMETTE MAGELLA , OUELLET JEAN‐FRANÇOIS 
Published: March 2005

The rapid growth and reabsorption of the avian ovary is thought to be adaptive, as it reduces predation risk and the metabolic cost of flight. In this paper, we use an extreme case of parental investment to show how the survival of gravid birds may be impaired by reduced take‐off ability. In still air, temporary flightlessness is regularly observed in female Common EidersSomateria mollissimapreparing for breeding. From a sample of pre‐laying females collected in the Baltic Sea, we quantified the relationships among body reserves, organ mass and take‐off ability using a general model of take‐off performance. Average body mass at the beginning and end of follicular growth was, respectively, 32% and 43% higher than winter body mass. Wing‐loading increased significantly during ovary development whereas the relative mass of flight muscles decreased. In contrast, organ mass and somatic body mass were constant from early follicular growth until laying, indicating that the observed increase in body mass was caused by ovary growth. The average specific lift production of individuals collected at the beginning of follicular growth was 9.7 N/kg, which is similar to the lift required to become airborne (9.8 N/kg). As ovary mass increased, lift production decreased to 9.2 N/kg at the onset of laying. These results indicate that temporary flightlessness results from the accumulation of large body reserves and subsequent ovarian growth. Predators of Common Eiders are diverse and may come from air, water and land. We suggest that temporary flightlessness may decrease adult survival through predation, and may represent an important cost of reproduction.
Of squeezers and skippers: factors determining the age at moult of immature African Penguins Spheniscus demersus in Namibia
Authors: KEMPER JESSICA , ROUX JEAN‐PAUL 
Published: March 2005

We used banding and resighting records of 391 African Penguins Spheniscus demersus banded as chicks and later resighted during immature moult to explain the roles of date of fledging and age at moult in determining the season of moult and its timing within the season. Breeding was continuous, but immature moult occurred mainly during spring and summer. Age at immature moult extended over 11 months, from 12 to 23 months after hatching. Birds that fledged during summer and early autumn generally moulted during the next moult season (squeezers), whereas birds that fledged in late autumn, winter and spring skipped the next moult season to moult only the following season (skippers). There was a significant relationship between age at moult and moult date, with young birds moulting later in the season than older birds. The age at moult of immature birds appears to be constrained by minimum age, moult seasonality and plumage wear. Birds that fledged over nearly 2 years moult during one season. Counts of moulting immature African Penguins have not been used to estimate year‐class strength and post‐fledging survival owing to the wide range of ages at immature moult. Our results provide the means of assigning recruits to specific age groups.
At‐sea distributions and abundance of tropicbirds in the eastern Pacific
Authors: SPEAR LARRY B. , AINLEY DAVID G. 
Published: March 2005

During spring and autumn 1980–95, we surveyed Red‐tailedPhaethon rubricauda, White‐tailedP. lepturusand Red‐billed TropicbirdsP. aethereusat sea in the Pacific between the coast of the Americas and 176°W. For the Pacific, we had complete coverage of the range ofaethereus, but only partial coverage of that ofrubricaudaandlepturus. Six areas of higher density were indicated: three ofrubricauda, two oflepturusand one ofaethereus. After pooling data across years, the ‘abundance’ (total number including subadults and adults) estimate forrubricaudawas 81 700 (boreal spring) and 86 500 (boreal autumn) birds. Abundance of each of the threerubricaudasubpopulations differed between seasons by about 50% despite seasonal consistency when populations were grouped. Furthermore, high densities ofrubricaudaoccurred at the edge of our study area, indicating that neither of the seasonal estimates for this species could be considered as total numbers. Abundance estimates oflepturusduring the non‐breeding season (when these birds had dispersed from colonies) were 11 000 and 41 500 birds for northern and southern populations, respectively. Estimated abundance ofaethereusduring the boreal spring was 26 700 birds, and 33 400 during the boreal autumn. Because tropicbirds are attracted to survey vessels, we also estimated the abundance after excluding those recorded as flying in a steady direction, or having been attracted to the ship. Considering only stationary birds (i.e. those that could not have been attracted), our minimum estimates were 41 000rubricauda, 15 750aethereus, 28 000 southernlepturusand 6400 northernlepturus.
Population size and trends of the Galápagos Penguin Spheniscus mendiculus
Authors: VARGAS HERNÁN , LOUGHEED CECILIA , SNELL HOWARD 
Published: March 2005

We applied a capture–mark–resight (CMR) method to estimate the population size of the Galápagos Penguin Spheniscus mendiculus. In 1999, we estimated 1198 individuals, with lower and upper 95% confidence limits of 1054 and 1403 individuals, respectively, and estimated that approximately 57% of the total population was counted in an annual census. Applying this estimate to the 2003 census, we estimated that the population size for the whole archipelago was 1351 individuals. We also applied the correction factor derived from the 1999 CMR data to other censuses carried out between 1970 and 2003 and estimated a maximum population of about 4000 individuals in 1971 when the highest numbers of Penguins were counted. Although the Penguin population size has fluctuated in the last 33 years, the overall trend shows larger populations in 1970–80 followed by relatively smaller populations and a slow recovery rate in 1983–2003. The data set also shows two major population declines (in 1983 and 1998), which are coincident with El Niño episodes.
At‐sea behaviour and habitat use by tropicbirds in the eastern Pacific
Authors: SPEAR LARRY B. , AINLEY DAVID G. 
Published: March 2005

During the boreal spring and autumn 1980–95, we surveyed Red‐tailed Phaethon rubricauda, White‐tailed P. lepturus and Red‐billed Tropicbirds P. aethereus at sea in the eastern Pacific. Two subpopulations were indicated for both rubricauda and lepturus, based on distribution hiatuses near the South Equatorial Current (see companion paper). Thus, five populations were examined, two each of rubricauda and lepturus, and one of aethereus. During the boreal spring, when equatorial current systems are less well developed, geographical variables (distance from nearest colony and nearest land) were the most important variables affecting tropicbird occurrence. However, sea‐surface salinity and thermal structure of the water column were the primary variables delineating tropicbird occurrence during the boreal autumn. Each tropicbird species utilized different species/sizes of aquatic predators (that make their prey available at the surface) that in turn utilize different oceanographic environments. We suspect that the distribution of aquatic predators is primarily responsible for colony locations and distribution of tropicbird species in the eastern Pacific.
The Course of Functional Decline in Older People with Persistently Elevated Depressive Symptoms: Longitudinal Findings from the Cardiovascular Health Study
Authors: Lenze Eric J. , Schulz Richard , Martire Lynn M. , Zdaniuk Bozena , Glass Thomas , Kop Willem J. , Jackson Sharon A. , Reynolds Charles F. 
Published: March 2005

Objectives: To examine the relationship between persistently high depressive symptoms and long‐term changes in functional disability in elderly persons.Design: A community‐based, prospective, observational study.Setting: Participant data from the Cardiovascular Health Study.Participants: From the overall sample of 5,888 subjects, three types of participants were identified for this study: (1) persistently depressed individuals, who experienced an onset of depressive symptoms that persisted over 4 years (n=119); (2) temporarily depressed individuals, who experienced an onset of depressive symptoms that resolved over time (n=259); and (3) nondepressed individuals, with persistently low depressive symptoms throughout the follow‐up period who were matched on baseline activity of daily living (ADL) scores, sex, and age to the previous two groups combined (n=378).Measurements: Four consecutive years of data were assessed: validated measures of depression (10‐item CES‐D), functional disability (10‐item ADL/instrumental ADL measure), physical performance, medical illness, and cognition.Results: The persistently depressed group showed a greater linear increase in functional disability ratings than the temporarily depressed and nondepressed groups. This association between persistent depression and functional disability was robust even when controlling for baseline demographic and clinical/performance measures, including cognition. The persistently depressed group had an adjusted odds ratio (OR) of 5.27 (95% confidence interval (CI) 3.03–9.16) for increased functional disability compared with the nondepressed group over 3 years of follow‐up, whereas the temporarily depressed group had an adjusted OR of 2.39 (95% CI=1.55–3.69) compared with the nondepressed group.Conclusion: Persistently elevated depressive symptoms in elderly persons are associated with a steep trajectory of worsening functional disability, generating the hypothesis that treatments for late‐life depression need to be assessed on their efficacy in maintaining long‐term functional status as well as remission of depressive symptoms. These results also demonstrate the need for studies to differentiate between persistent and temporary depressive symptoms when examining their relationship to disability.
The Effect of a Task‐Oriented Walking Intervention on Improving Balance Self‐Efficacy Poststroke: A Randomized, Controlled Trial
Authors: Salbach Nancy M. , Mayo Nancy E. , Robichaud‐Ekstrand Sylvie , Hanley James A. , Richards Carol L. , Wood‐Dauphinee Sharon 
Published: March 2005

Objectives: To evaluate the efficacy of a task‐oriented walking intervention in improving balance self‐efficacy in persons with stroke and to determine whether effects were task‐specific, influenced by baseline level of self‐efficacy and associated with changes in walking and balance capacity.Design: Secondary analysis of a two‐center, observer‐blinded, randomized, controlled trial.Setting: General community.Participants: Ninety‐one individuals with a residual walking deficit within 1 year of a first or recurrent stroke.Intervention: Task‐oriented interventions targeting walking or upper extremity (UE) function were provided three times a week for 6 weeks.Measurements: Activities‐specific Balance Confidence Scale, Six‐Minute Walk Test, 5‐m walk, Berg Balance Scale, and Timed “Up and Go” administered at baseline and postintervention.Results: The walking intervention was associated with a significantly greater average proportional change in balance self‐efficacy than the UE intervention. Treatment effects were largest in persons with low self‐efficacy at baseline and for activities relating to tasks practiced. In the walking group, change in balance self‐efficacy correlated with change in functional walking capacity (correlation coefficient=0.45, 95% confidence interval=0.16–0.68). Results of multivariable modeling suggested effect modification by the baseline level of depressive symptoms and a prognostic influence of age, sex, comorbidity, time poststroke, and functional mobility on change in self‐efficacy.Conclusion: Task‐oriented walking retraining enhances balance self‐efficacy in community‐dwelling individuals with chronic stroke. Benefits may be partially the result of improvement in walking capacity. The influence of baseline level of self‐efficacy, depressive symptoms, and prognostic variables on treatment effects are of clinical importance and must be verified in future studies.