2,159 research outputs found
Immediate replacement of fishing with dairying by the earliest farmers of the NE Atlantic archipelagos
The appearance of farming, from its inception in the Near East around 12 000 years ago, finally reached the northwestern extremes of Europe by the fourth millennium BC or shortly thereafter. Various models have been invoked to explain the Neolithization of northern Europe; however, resolving these different scenarios has proved problematic due to poor faunal preservation and the lack of specificity achievable for commonly applied proxies. Here, we present new multi-proxy evidence, which qualitatively and quantitatively maps subsistence change in the northeast Atlantic archipelagos from the Late Mesolithic into the Neolithic and beyond. A model involving significant retention of hunterâgathererâfisher influences was tested against one of the dominant adoptions of farming using a novel suite of lipid biomarkers, including dihydroxy fatty acids, Ď-(o-alkylphenyl)alkanoic acids and stable carbon isotope signatures of individual fatty acids preserved in cooking vessels. These new findings, together with archaeozoological and human skeletal collagen bulk stable carbon isotope proxies, unequivocally confirm rejection of marine resources by early farmers coinciding with the adoption of intensive dairy farming. This pattern of Neolithization contrasts markedly to that occurring contemporaneously in the Baltic, suggesting that geographically distinct ecological and cultural influences dictated the evolution of subsistence practices at this critical phase of European prehistory
First light for avian embryos: eggshell thickness and pigmentation mediate variation in development and UV exposure in wild bird eggs
Article first published online: 29 JUL 20141. The avian embryo's development is influenced by both the amount and the wavelength of the light that passes through the eggshell. Commercial poultry breeders use light of specific wavelengths to accelerate embryonic growth, yet the effects of the variably patterned eggshells of wild bird species on light transmission and embryonic development remain largely unexplored. 2. Here, we provide the first comparative phylogenetic analysis of light transmission, through a diverse range of bird eggshells (74 British breeding species), in relation to the eggshell's thickness, permeability, pigment concentration and surface reflectance spectrum (colour). 3. The percentage of light transmitted through the eggshell was measured in the spectral range 250â700 nm. Our quantitative analyses confirm anecdotal reports that eggshells filter the light of the externally coloured shell. Specifically, we detected a positive relationship between surface eggshell reflectance (âbrightnessâ) and the percentage of light transmitted through the eggshell, and this relationship was strongest at wavelengths in the human-visible blue-green region of the spectra (c. 435 nm). 4. We show that less light passes through thicker eggshells with greater total pigment concentrations. By contrast, permeability (measured as water vapour conductance) did not covary significantly with light transmission. Eggs of closed-nesting species let more light pass through, compared with open nesters. 5. We postulate that greater light transmission is required to assist embryonic development under low light exposure. Importantly, this result provides an ecological explanation for the repeated evolution of immaculate, white- or pale-coloured eggshells in species nesting in enclosed spaces. 6. Finally, we detected correlative support for the solar radiation hypothesis, in that eggshells of bird species with a longer incubation period let significantly less of the potentially harmful, ultraviolet (UV) light pass through the eggshell. In summary, we demonstrate suites of avian eggshell properties, including eggshell structure and pigmentation, which are consistent with an evolutionary pressure to both enhance and protect embryonic development.Golo Maurer, Steven J. Portugal, Mark E. Hauber, Ivan MikĹĄĂk, Douglas G. D. Russell and Phillip Casse
Testing a Grassroots Citizen Science Venture Using Open Design, âthe Bee Lab Projectâ
The Bee Lab project applies Citizen Science and Open Design to beekeeping, enabling participants to construct monitoring devices gathering reciprocal data, motivating participants and third parties. The presented approach uses design workshops to provide insight into the design of kits, user motivations, promoting reciprocal interests and address community problems. This paper signposts issues and opportunities in the process of designing Citizen Science tools for communities using Open Design to solve individual problems, including: downloadable design for social/local change, laypeople creating technology and repairable kits
Host species determines egg size in Oriental cuckoo
Š 2018 The Zoological Society of London.The Oriental cuckoo Cuculus optatus is an obligate brood parasite associated with species of the genus Phylloscopus. Four distinct phenotypes of Oriental cuckoo eggs, matching eggshell colour patterns of Arctic warbler Phylloscopus borealis, common chiffchaff (Siberian) P. collybita tristis, yellow-browed warbler P. inornatus and Pallas's leaf warbler P. proregulus, have been identified in the Russian part of its breeding area. We compared egg length, breadth and volume of Oriental cuckoo egg phenotypes with eggs of the corresponding hosts from three geographical regions in Russia: the Urals, Siberia and the Far East. We found significant oometric differences between Oriental cuckoo egg phenotypes. Egg breadth of each cuckoo group matched the egg breadth of the host species, while the length of cuckoo eggs did not match egg length in host species. Our results can be explained in terms of clutch geometry. An egg sticking out above the clutch is likely to be rejected by the host and so breadth should match the host's egg. This constrains cuckoos in maintaining large egg volumes, which are essential for providing a cuckoo chick with the energy required to eject the host eggs and chicks. An increased egg length might compensate for breadth constraints. We suggest that the size of cuckoo eggs might also be affected by parental care - when only one parent is involved in feeding, eggs need to be larger. This might explain why the longest cuckoo eggs belonged to the phenotype parasitizing the smallest host, Pallas's leaf warbler, where only one parent feeds the chicks. In our view, differences in egg sizes of Oriental cuckoo phenotypes provide evidence of their adaptations to brood parasitism on small leaf warbler species.Peer reviewe
Bacteria and the evolution of honest signals. The case of ornamental throat feathers in spotless starlings
1. Mechanisms guaranteeing reliability of messages are essential in understanding the underlying
information and evolution of signals. Micro-organisms may degrade signalling traits and
therefore influence the transmitted information and evolution of these characters. The role of
micro-organisms in animal signalling has, however, rarely been investigated.
2. Here, we explore a possible role for feather-degrading bacteria driving the design of ornamental
throat feathers in male spotless starlings (Sturnus unicolor). We estimated length, bacterial
load, degradation status and susceptibility to degradation by keratinolytic bacteria in
those feathers, compared with non-ornamental adjacent feathers in males, as well as to throat
feathers in females. In addition, the volume of the uropygial gland and its secretion was measured
and the secretion extracted. We also experimentally evaluated the capacity of each secretion
to inhibit growth of a keratinolytic bacterium.
3. The apical part of male ornamental throat feathers harboured more bacteria and degraded
more quickly than the basal part; these patterns were not detected in female throat feathers or
in non-ornamental male feathers. Moreover, degradation status of male and female throat
feathers did not differ, but was positively associated with feather bacterial density. Finally, the
size of the uropygial gland in both males and females predicted volume and the inhibitory
capacity of secretion against feather-degrading bacteria. Only in males was uropygial gland
size negatively associated with the level of feather degradation.
4. All results indicate differential susceptibility of different parts of throat feathers to keratinolytic
bacterial attack, which supports the possibility that throat feathers in starlings reflect individual
ability to combat feather-degrading bacteria honestly. This is further supported by the
relationship detected between antimicrobial properties of uropygial secretion and the level of
feather degradation.
5. Our results suggest that selection pressures exerted by feather-degrading bacteria on hosts
may promote evolution of particular morphologies of secondary sexual traits with different
susceptibility to bacterial degradation that reliably inform of their bacterial load. Those results
will help to understand the evolution of ornamental signals.This work was financed by Spanish Ministerio de Ciencia e Innovaci on, European
funds (FEDER) (CGL2010-19233-C03-01, CGL2013-48193-C3-1-P). MRR and DMG received a postdoc from the program âJAE-Docâ, GT from the âJuan de la Ciervaâ, and CRC had a predoctoral fellowship, all from the Spanish Government.Peer reviewe
Associations of the mechanical, anthropometric and gait contributors to the knee adduction moment during paediatric gait
The knee adduction moment (KAM) during gait has been proposed as an
indirect measure of dynamic knee joint loading and has been reported to be higher in obese
children [1, 2]. The KAM is primarily calculated from the resultant ground reaction force
(GRF) and the lever arm length, both of which can be manipulated through weight-loss or
medical interventions [1]. However, there is little data on the relationships between the
mechanical, anthropometric and gait contributors to the KAM during paediatric gait. The
objectives of the study were to examine the associations with the first (1st) and second (2nd)
peak KAM (pKAM) and: (1) centre of pressure (CoP), KAM lever arm length, vertical and
mediolateral ground reaction forces (GRF) and, (2) fat mass, height, step width, foot rotation,
knee rotation and walking velocity
Reliability of three foot models to examine paediatric gait
Background
A variety of multi-segmental foot models have been produced
to examine patterns of foot segmental movement
during gait cycle to identify biomechanical differences
between normal and pathological foot function[1-3].
The reliability of foot models to accurately describe
motion of the foot joints is dependent on the ability of
the examiner to repeatedly apply markers to specific
landmarks and the relevance of modelsâ segmental
descriptions to underlying anatomy. The aim of this
study was to test the reliability of segmental angles measured
by three published foot models during paediatric
gait.
Materials and methods
Sixteen children, aged 6 to 12 years old, were recruited
to the study. Marker sets for three foot models 3DFoot
[1], Oxford Foot Model (OFM)[2], and Kinfoot[3] were
applied to their right feet simultaneously which to the
authors knowledge, is the first direct comparison of the
three models during gait. Each foot model was assessed
for repeatability of maximal joint angle and range of
motion during the gait cycle between two testing occasions.
Absolute angular differences and standard error
of measurement (SEM) are reported.
Results
Repeatability of all maximal segmental angles and range
of motions were higher in 3DFoot compared to OFM
and Kinfoot (Table 1)
Evaluation of multi-segmental kinematic modelling in the paediatric foot using three concurrent foot models
Background:
Various foot models are used in the analysis of foot motion during gait and selection of the
appropriate model can be difficult. The clinical utility of a model is dependent on the repeatability of the data as
well as an understanding of the expected error in the process of data collection. Kinematic assessment of the
paediatric foot is challenging and little is reported about multi-segment foot models in this population. The aim of
this study was to examine three foot models and establish their concurrent test-retest repeatability in evaluation of
paediatric foot motion during gait.
Methods:
3
DFoot, Kinfoot and the Oxford Foot Model (OFM) were applied concurrently to the right foot and lower
limb of 14 children on two testing sessions. Angular data for foot segments were extracted at gait cycle events and
peaks and compared between sessions by intraclass correlation coefficient (ICC) with 95% confidence intervals (95%
CI) and standard error of measurement (SEM).
Results:
All foot models demonstrated moderate repeatability: OFM (ICC 0.55, 95% CI 0.16 to 0.77), 3DFoot (ICC
0.47, 95% CI 0.15 to 0.64) and Kinfoot (ICC 0.43, 95% CI
â
0.03 to 0.59). On the basis of a cut-off of 5°, acceptable
mean error over repeated sessions was observed for OFM (SEM 4.61° ¹ 2.86°) and 3DFoot (SEM 3.88° ¹ 2.18°) but not
for Kinfoot (SEM 5.08° ¹ 1.53°). Reliability of segmental kinematics varied, with low repeatability (ICC < 0.4) found for
14.3% of OFM angles, 22.7% of 3DFoot angles and 37.6% of Kinfoot angles. SEM greater than 5° was found in 26.2%
of OFM, 15.2% of 3DFoot, and 43.8% of Kinfoot segmental angles.
Conclusion:
Findings from this work have demonstrated that segmental foot kinematics are repeatable in the
paediatric foot but the level of repeatability and error varies across the segments of the different models.
Information on repeatability and test-retest errors of three-dimensional foot models can better inform clinical
assessment and advance understanding of foot motion during gai
Developing a group intervention to manage fatigue in rheumatoid arthritis through modifying physical activity
Š 2019 The Author(s). Background: Fatigue is a major symptom of rheumatoid arthritis (RA). There is some evidence that physical activity (PA) may be effective in reducing RA fatigue. However, few PA interventions have been designed to manage fatigue and there is limited evidence of end-user input into intervention development. The aim of this research was to co-design an intervention to support self-management of RA fatigue through modifying PA. Methods: A series of studies used mixed methodological approaches to co-design a fatigue management intervention focused on modifying PA based on UK Medical Research Council guidance, and informed by the Behaviour Change Wheel theoretical framework. Development was based on existing evidence, preferences of RA patients and rheumatology healthcare professionals, and practical issues regarding intervention format, content and implementation. Results: The resulting group-based intervention consists of seven sessions delivered by a physiotherapist over 12 weeks. Each session includes an education and discussion session followed by supervised PA chosen by the participant. The intervention is designed to support modification and maintenance of PA as a means of managing fatigue. This is underpinned by evidence-based behaviour change techniques that might support changes in PA behaviour. Intervention delivery is interactive and aims to enhance capability, opportunity and motivation for PA. Conclusion: This study outlines stages in the systematic development of a theory-based intervention designed through consultation with RA patients and healthcare professionals to reduce the impact of RA fatigue. The feasibility of future evaluation of the intervention should now be determined
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