bluuebunny/crossref_metadata_2025_split huggingface dataset:
Geographical ecology of Paraguayan bats: spatial integration and metacommunity structure of interacting assemblages
Authors: STEVENS RICHARD D. , LÓPEZ‐GONZÁLEZ CELIA , PRESLEY STEVEN J. 
Published: August 2007

Summary

We examined the relative contributions of regional spatial characteristics and local environmental conditions in determining Paraguayan bat species composition.
We used a suite of full and partial redundancy analyses to estimate four additive partitions of variance in bat species composition: (a) unexplained variation, (b) that explained purely by spatial characteristics, (c) that explained purely by local environmental conditions and (d) that explained jointly by space and environment. The spatial component to bat species composition was greater than the environmental component and both pure spatial and pure environmental characteristics accounted for significant amounts of variation in bat species composition.
Results from variance decomposition suggest that the mass effects model describes metacommunity structure of Paraguayan bats better than species sorting or neutral models. Such mass effects may potentially be general for bats and could explain the inability of purely local factors to fully account for bat community organization. Mass effects also have substantial conservation implications because rescue effects may enhance the persistence of mobile species in fragmented landscapes with relatively few protected sites.
The anatomy of predator–prey dynamics in a changing climate
Authors: WILMERS CHRISTOPHER C. , POST ERIC , HASTINGS ALAN 
Published: August 2007

Summary

Humans are increasingly influencing global climate and regional predator assemblages, yet a mechanistic understanding of how climate and predation interact to affect fluctuations in prey populations is currently lacking.
Here we develop a modelling framework to explore the effects of different predation strategies on the response of age‐structured prey populations to a changing climate.
We show that predation acts in opposition to temporal correlation in climatic conditions to suppress prey population fluctuations.
Ambush predators such as lions are shown to be more effective at suppressing fluctuations in their prey than cursorial predators such as wolves, which chase down prey over long distances, because they are more effective predators on prime‐aged adults.
We model climate as a Markov process and explore the consequences of future changes in climatic autocorrelation for population dynamics. We show that the presence of healthy predator populations will be particularly important in dampening prey population fluctuations if temporal correlation in climatic conditions increases in the future.
Estimating expenditure on male and female offspring in a sexually size‐dimorphic bird: a comparison of different methods
Authors: MAGRATH MICHAEL J. L. , VAN LIESHOUT EMILE , PEN IDO , VISSER G. HENK , KOMDEUR JAN 
Published: August 2007

Summary

The parents of sexually size‐dimorphic offspring are often assumed to invest more resources producing individuals of the larger sex. A range of different methods have been employed to estimate relative expenditure on the sexes, including quantifying sex‐specific offspring growth, food intake, energy expenditure and energy intake, in addition to measures of parental food provisioning and energy expenditure. These methods all have the potential to provide useful estimates of relative investment, but each has particular problems of interpretation, and few studies have compared the estimates derived concurrently from more than two of these measures.
In this study we compared these surrogate measures of parental investment in the brown songlark Cinclorhamphus cruralis, which exhibits one of the most extreme cases of sexual size dimorphism among birds.
At 10 days of age we found that male chicks, on average, were 49% heavier, received 42% more prey items, expended 44% more energy and ingested 50% more metabolizable energy than their sisters.
Furthermore, we created, experimentally, both all‐male and all‐female broods of 10‐day‐old chicks and found that mothers delivered 43% more prey items and expended 27% more energy when provisioning all‐male broods, providing the first direct evidence for a change in parental energy expenditure in relation to brood sex ratio.
These data reveal remarkable agreement between these estimates of investment and suggest that all may provide quantitatively useful information on sex allocation. However, the lower variance associated with estimates of relative mass and energy intake suggest that these methods may be of greater utility, although this may primarily reflect the shorter period over which our provisioning data were collected.
Evidence of an interannual effect of maternal immunization on the immune response of juveniles in a long‐lived colonial bird
Authors: STASZEWSKI VINCENT , GASPARINI JULIEN , MCCOY KAREN. D. , TVERAA TORKILD , BOULINIER THIERRY 
Published: August 2007

SummaryLittle is known about the maternal transfer of antibodies in natural host–parasite systems despite its possible evolutionary and ecological implications. In domestic animals, the maternal transfer of antibodies can enhance offspring survival via a temporary protection against parasites, but it can also interfere with the juvenile immune response to antigens.We tested the functional role of maternal antibodies in a natural population of a long‐lived colonial seabird, the kittiwake (Rissa tridactyla), using a vaccine (Newcastle disease virus vaccine) to mimic parasite exposure combined with a cross‐fostering design.We first investigated the role of prior maternal exposure on the interannual transmission of Ab to juveniles. We then tested the effect of these antibodies on the juvenile immune response to the same antigen.The results show that specific maternal antibodies were transferred to chicks 1 year after maternal exposure and that these antibodies were functional, i.e. they affected juvenile immunity. These results suggest that the role of maternal antibodies may depend on the timing and pattern of offspring exposure to parasites, along with the patterns of maternal exposure and the dynamics of her immune response.Overall, our approach underlines that although the transgenerational transfer of antibodies in natural populations is likely to have broad implications, the nature of these effects may vary dramatically among host–parasite systems, depending on the physiological mechanisms involved and the ecological context.
Climate change can alter competitive relationships between resident and migratory birds
Authors: AHOLA MARKUS P. , LAAKSONEN TONI , EEVA TAPIO , LEHIKOINEN ESA 
Published: August 2007

Summary

Climate change could affect resource competition between resident and migratory bird species by changing the interval between their onsets of breeding or by altering their population densities.
We studied interspecific nest‐hole competition between resident great tits and migrant pied flycatchers in South‐Western Finland over the past five decades (1953–2005).
We found that appearance of fatal take‐over trials, the cases where a pied flycatcher tried to take over a great tit nest but was killed by the tit, increased with a reduced interspecific laying date interval and with increasing densities of both tits and flycatchers. The probability of pied flycatchers taking over great tit nests increased with the density of pied flycatchers.
Laying dates of the great tit and pied flycatcher are affected by the temperatures of different time periods, and divergent changes in these temperatures could consequently modify their competitive interactions. Densities are a result of reproductive success and survival, which can be affected by separate climatic factors in the resident great tit and trans‐Saharan migrant pied flycatcher.
On these bases we conclude that climate change has a great potential to alter the competitive balance between these two species.
Where do the feral oilseed rape populations come from? A large‐scale study of their possible origin in a farmland area
Authors: Pivard S. , Adamczyk K. , Lecomte J. , Lavigne C. , Bouvier A. , Deville A. , Gouyon P. H. , Huet S. 
Published: August 2007

Summary

Many cultivated species can escape from fields and colonize seminatural habitats as feral populations. Of these, feral oilseed rape is a widespread feature of field margins and roadside verges. Although considered in several studies, the general processes leading to the escape and persistence of feral oilseed rape are still poorly known. Notably, it remains unclear whether these annuals form transient populations resulting mainly from seed immigration (either from neighbouring fields or during seed transport), or whether they show real ability to persist (either through self‐recruitment or seed banks).
We conducted a 4‐year large‐scale study of factors involved in the presence of feral oilseed rape populations in a typical open‐field area of France. The results were subjected to statistical methods suitable for analysing large data sets, based on a regression approach. We subsequently addressed the relative contribution of the ecological processes identified as being involved in the presence of feral populations.
Many feral oilseed rape populations resulted from seed immigration from neighbouring fields (about 35–40% of the observed feral populations). Immigration occurred at harvest time rather than at sowing. Around 15% of such populations were attributed to immigration through seed transport.
The other half resulted from processes of persistence, mainly through persistent seed banks (35–40% of the observed feral populations). This was all the more unexpected because seed banks have not yet been documented on road verges (despite being frequent within fields). Local recruitment was rare, accounting for no more than 10% of the feral populations.
Synthesis and applications. Understanding the dynamics of feral oilseed rape populations is crucial for evaluating gene flow over an agro‐ecosystem. Our results show that, while many feral populations do come from annual seed dispersal, a significant number also result from seeds stored in the soil for several years. In the current context of coexistence and management of transgenic with non‐transgenic crops, feral persistence and, especially, the seed bank contribution to the dynamics of feral populations need to be considered seriously. The latter, combined with self‐recruitment, indicates a high potential for the persistence of transgenes and the possible emergence of gene‐stacking.
A two‐colour chewing gum test for masticatory efficiency: development of different assessment methods
Authors: SCHIMMEL M. , CHRISTOU P. , HERRMANN F. , MÜLLER F. 
Published: August 2007

Summary  Objective:  The aim of this study was to investigate different assessment methods of a two‐colour chewing gum test for masticatory efficiency to determine its validity for research and clinical purposes.Materials and methods:  Twenty adult volunteers, eleven women and nine men (mean age of 27·5 years), participated in this study. All participants perceived their masticatory efficiency as normal. The task was to chew five samples of a two‐colour chewing gum for 5, 10, 20, 30 and 50 cycles respectively. Maximum bite force was measured. All samples were assessed twice by two independent operators both, as ‘bolus’ and after flattening to 1 mm thick ‘wafers’. The latter were scanned and the unmixed pixels counted using Adobe Photoshop Elements® to calculate the ratio of unmixed colour to the total surface.Results:  Digital image processing confirmed a significant correlation between colour mixing and chewing duration (P < 0·001). Subjective assessment proved less accurate with fair to substantial intra‐examiner agreement for ‘bolus’ (0·20 < kappa < 0·63) and substantial to almost perfect agreement for ‘wafer’ (0·60 < kappa < 0·88). Inter‐examiner agreement was consistently moderate or substantial only for specimen chewed 20 cycles or longer. No significant correlation was found between the colour mixture and the maximum bite force.Conclusion:  Digital image processing of the two‐colour chewing gum test specimen provides reliable quantitative data for chewing efficiency. Visual assessments were less reliable but might still be useful in screening for chewing deficiencies in a clinical setting. In this context, the test should be performed with a flattened specimen chewed, probably for 20 cycles.
The effects of one night of sleep deprivation on known‐risk and ambiguous‐risk decisions
Authors: MCKENNA BENJAMIN S. , DICKINSON DAVID L. , ORFF HENRY J. , DRUMMOND SEAN P. A. 
Published: August 2007

SummarySleep deprivation has been shown to alter decision‐making abilities. The majority of research has utilized fairly complex tasks with the goal of emulating ’real‐life’ scenarios. Here, we use a Lottery Choice Task (LCT) which assesses risk and ambiguity preference for both decisions involving potential gains and those involving potential losses. We hypothesized that one night of sleep deprivation would make subjects more risk seeking in both gains and losses. Both a control group and an experimental group took the LCT on two consecutive days, with an intervening night of either sleep or sleep deprivation. The control group demonstrated that there was no effect of repeated administration of the LCT. For the experimental group, results showed significant interactions of night (normal sleep versus total sleep deprivation, TSD) by frame (gains versus losses), which demonstrate that following as little as 23 h of TSD, the prototypical response to decisions involving risk is altered. Following TSD, subjects were willing to take more risk than they ordinarily would when they were considering a gain, but less risk than they ordinarily would when they were considering a loss. For ambiguity preferences, there seems to be no direct effect of TSD. These findings suggest that, overall, risk preference is moderated by TSD, but whether an individual is willing to take more or less risk than when well‐rested depends on whether the decision is framed in terms of gains or losses.
Intensive Sleep Retraining treatment for chronic primary insomnia: a preliminary investigation
Authors: HARRIS JODIE , LACK LEON , WRIGHT HELEN , GRADISAR MICHAEL , BROOKS AMBER 
Published: August 2007

SummaryThe aim of this study was to assess the effectiveness of Intensive Sleep Retraining, a novel, short duration behavioural therapy in treating chronic primary insomnia. Seventeen consecutive volunteers from the general public (mean age = 39.1 years), meeting selection criteria for chronic primary insomnia participated in the treatment study. The study was performed as a case replication series. Assessment involved sleep diary, actigraph and questionnaire measures of sleep and daytime functioning for a period of 2 weeks prior to, immediately after, and 6 weeks following the treatment. Treatment involved a single night of sleep deprivation, facilitating short sleep latencies (mean: 6.9 min) to a series of 50 brief nap opportunities. Following treatment, Sleep Onset Latency significantly decreased by a mean of 30.5 min (SD = 28.3), Wake Time after Sleep Onset significantly decreased by a mean of 28 min (SD = 34.0), and Total Sleep Time significantly increased by 64.6 min (SD = 45.5). Significant improvements were also seen in the daytime functioning and psychological measures of fatigue and vigour, cognitive sleep anticipatory anxiety and self‐efficacy for sleep. This brief therapy was effective in improving sleep and some daytime functioning and psychological questionnaire measures. These improvements were maintained up to 2 months following the treatment weekend. Further exploration of this brief therapy is needed, with larger, randomized, placebo‐controlled trials over longer follow‐up periods, and in comparison to other traditional therapies for insomnia.
Mood changes after sleep deprivation in morningness–eveningness chronotypes in healthy individuals
Authors: SELVI YAVUZ , GULEC MUSTAFA , AGARGUN MEHMET YUCEL , BESIROGLU LUTFULLAH 
Published: August 2007

SummaryInconsistent results have been found in the studies evaluating the effect of both total and partial sleep deprivation (SD) on mood in healthy subjects and a few variables have been analyzed as possible predictors. In the present study, we examined whether circadian preference modifies the effect of SD on mood changes in healthy subjects. Sample consisted of 60 healthy volunteers (including 30 morningness and 30 eveningness subjects). Then, the two groups were again divided into two groups for two SD procedures. Fifteen morningness and 15 eveningness chronotypes were total sleep deprived and 15 morningness and 15 eveningness subjects were partial sleep deprived. The mood changes were evaluated before and after SD using Profile of Mood States. Two main results were obtained from our study: a significant increase in depression subscale in morningness chronotypes and a significant decrease in depression subscale score after total SD (TSD) in eveningness chronotypes. The changes in depression‐dejection scores of eveningness chronotypes after total (P < 0.01) and partial SD (P < 0.01) were significantly different from changes in morningness chronotypes after TSD. Our results suggest that the effect of SD on mood in normal subjects is related to their circadian preferences. The morningness or eveningness characteristics of the shift workers have significant impact on their mood states. Therefore, adjusting the work schedule with the morningness and eveningness characteristics of the workers may improve their mood alterations.
The relationship between craniofacial anatomy and obstructive sleep apnoea: a case‐controlled study
Authors: JOHAL AMA , PATEL SHIVANI I. , BATTAGEL JOANNA M. 
Published: August 2007

SummaryThe aim of the study was to identify craniofacial and pharyngeal anatomical factors directly related to obstructive sleep apnoea (OSA). The design and setting was a hospital‐based, case‐controlled study. Ninety‐nine subjects (78 males and 21 females) with a confirmed diagnosis of OSA, who were referred to the Dental Hospital for construction of a mandibular advancement splint were recruited. A similar number of control subjects, matched for age and sex, were recruited after completing snoring and Epworth Sleepiness Scale questionnaires to exclude habitual snoring and daytime sleepiness. An upright cephalogram was obtained and skeletal and soft tissue landmarks were traced and digitized. In OSA subjects the anteroposterior skeletal measurements, including maxillary and mandibular length were reduced (P < 0.001). The intermaxillary space was found to be 3.1 mm shorter in OSA subjects (P = 0.001). The nasopharyngeal airway in OSA subjects was narrower (P < 0.001) but pharyngeal length showed no difference. The tongue size was increased (P = 0.021), soft plate length, thickness and area were all greater (P < 0.001) and the hyoid bone was more inferiorly positioned in OSA subjects (P < 0.001). This study identifies a significant number of craniofacial and pharyngeal anatomical factors directly related to OSA.
Depression: relationships to sleep paralysis and other sleep disturbances in a community sample
Authors: SZKLO‐COXE MARIANA , YOUNG TERRY , FINN LAUREL , MIGNOT EMMANUEL 
Published: August 2007

SummarySleep disturbances are important correlates of depression, with epidemiologic research heretofore focused on insomnia and sleepiness. This epidemiologic study’s aim was to investigate, in a community sample, depression’s relationships to other sleep disturbances: sleep paralysis (SP), hypnagogic/hypnopompic hallucinations (HH), cataplexy – considered rapid eye movement‐related disturbances – and automatic behavior (AB). Although typical of narcolepsy, these disturbances are prevalent, albeit under‐studied, in the population. Cross‐sectional analyses (1998–2002), based on Wisconsin Sleep Cohort Study population‐based data from 866 participants (mean age 54, 53% male), examined: depression (Zung Self‐Rating Depression Scale), trait anxiety (Spielberger State‐Trait Anxiety Inventory, STAI‐T ≥ 75th percentile), and self‐reported sleep disturbances. Descriptive sleep data were obtained by overnight polysomnography. Adjusted logistic regression models estimated depression’s associations with each (>few times ever) outcome – SP, HH, AB, and cataplexy. Depression’s associations with self‐reported SP and cataplexy were not explained by anxiety. After anxiety adjustment, severe depression (Zung ≥55), vis‐à‐vis Zung <50, increased SP odds ∼500% (P = 0.0008). Depression (Zung ≥50), after stratification by anxiety given an interaction (P = 0.02), increased self‐reported cataplexy odds in non‐anxious (OR 8.9, P = 0.0008) but not anxious (OR 1.1, P = 0.82) participants. Insomnia and sleepiness seemed only partial mediators or confounders for depression’s associations with self‐reported cataplexy and SP. Anxiety (OR 1.9, P = 0.04) partially explained depression’s (Zung ≥55) association with HH (OR 2.2, P = 0.08). Anxiety (OR 1.6, P = 0.02) was also more related than depression to AB. Recognizing depression’s relationships to oft‐neglected sleep disturbances, most notably SP, might assist in better characterizing depression and the full range of its associated sleep problems in the population. Longitudinal studies are warranted to elucidate mediators and causality.
Low‐molecular‐weight post‐translationally modified microcins
Authors: Severinov Konstantin , Semenova Ekaterina , Kazakov Alexey , Kazakov Teymur , Gelfand Mikhail S. 
Published: August 2007

SummaryMicrocins are a class of ribosomally synthesized antibacterial peptides produced by Enterobacteriaceae and active against closely related bacterial species. While some microcins are active as unmodified peptides, others are heavily modified by dedicated maturation enzymes. Low‐molecular‐weight microcins from the post‐translationally modified group target essential molecular machines inside the cells. In this review, available structural and functional data about three such microcins – microcin J25, microcin B17 and microcin C7‐C51 – are discussed. While all three low‐molecular‐weight post‐translationally modified microcins are produced by Escherichia coli, inferences based on sequence and structural similarities with peptides encoded or produced by phylogenetically diverse bacteria are made whenever possible to put these compounds into a larger perspective.