Epidemiology of protozoan and helminthic parasites in wild passerine birds of Britain and Ireland.

Avian endoparasites play important roles in conservation, biodiversity and host evolution. Currently, little is known about the epidemiology of intestinal helminths and protozoans infecting wild birds of Britain and Ireland. This study aimed to determine the rates of parasite prevalence, abundance and infection intensity in wild passerines. Fecal samples (n = 755) from 18 bird families were collected from 13 sites across England, Wales and Ireland from March 2020 to June 2021. A conventional sodium nitrate flotation method allowed morphological identification and abundance estimation of eggs/oocysts. Associations with host family and age were examined alongside spatiotemporal and ecological factors using Bayesian phylogenetically controlled models. Parasites were detected in 20.0% of samples, with corvids and finches having the highest prevalences and intensities, respectively. Syngamus (33%) and Isospora (32%) were the most prevalent genera observed. Parasite prevalence and abundance differed amongst avian families and seasons, while infection intensity varied between families and regions. Prevalence was affected by diet diversity, while abundance differed by host age and habitat diversity. Infection intensity was higher in birds using a wider range of habitats, and doubled in areas with feeders present. The elucidation of these patterns will increase the understanding of parasite fauna in British and Irish birds.

To fuse or not to fuse: The elderly patient with lumbar stenosis and low-grade spondylolisthesis. Systematic review and meta-analysis of randomised controlled trials.

BACKGROUND: The optimum surgical intervention for elderly patients with lumbar spinal stenosis (LSS) and low-grade degenerative-spondylolisthesis (LGDS) has been extensively debated. We conducted a systematic review and meta-analysis of randomised-controlled-trials (RCTs) comparing the effectiveness of decompression-alone against the gold-standard approach of decompression-with-fusion (D + F) in elderly patients with LSS and LGDS. METHODS: A systematic literature search was performed on published databases from inception to October-2021. English-language RCTs of elderly patients (mean age over-65) with LSS and LGDS, who had undergone DA or D + F were included. The quality and weight of evidence was assessed, and a meta-analysis performed. RESULTS: Six RCTs (n = 531; mean age: 66.2 years; 57.8% female) were included. There was no difference in visual-analogue-scale (VAS) scores of back-pain (BP) or leg-pain (LP) at mean follow-up of 27.4 months between both DA and D + F groups (BP: mean-difference (MD)0.24, 95%CI: -0.38-0.85; LP MD:0.39, 95%CI: -0.34-1.11). No difference in disability, measured by Oswestry-Disability-Index scores, was found between both groups (MD:0.50, 95%CI: -3.31-4.31). However, patients in DA group had less hospital complications and fewer adverse events (total-surgical-complications OR:0.57, 95%CI: 0.36-0.90), despite a higher rate of worsening DS (OR:3.49, 95%CI: 1.05-11.65). No difference in BP or LP was found in subgroup-analysis of open-laminectomy compared to posterolateral-fusion (PLF) (BP: MD: -0.24, 95%CI: -1.80-1.32; LP MD:0.80, 95%CI: -0.95-2.55). CONCLUSIONS: DA is not inferior to D + F in elderly patients with LSS and LGDS. DA carries a lower risk of hospital complications and fewer adverse events, however, surgeons should weigh these findings with the increased risk of DS progressing post-operatively.

Insights in Human Hair Curvature by Proteome Analysis of Two Distinct Hair Shapes.

Scalp hair is a universal human characteristic, and a wide range of hair shape and color variations exists. Although differences in human scalp hair shape are visually apparent, the underpinning molecular insights are yet to be fully explored. This work reports the determination of differences at the protein level between two distinct groups of hair shape: very straight samples versus very curly hair samples. An in-depth highresolution liquid-chromatography mass spectrometry proteome analysis study was performed on hair samples from 50 individuals (pooled in 10 × 5 samples) with very curly hair and 50 subjects with very straight hair (pooled in 10 × 5 samples) to decipher differences between the two experimental groups at the protein level. Our results demonstrate that a distinction between the two experimental groups (very straight vs. very curly) can be made based on their overall protein profiles in a multivariate analysis approach. Further investigation of the protein expression levels between these two groups pinpointed 13 unique proteins which were found to be significantly different between the two groups, with an adjusted p-value < 0.05 and a fold change of more than two. Although differences between the very curly and the very straight hair sample groups could be identified, linkage between population differences and curl phenotype is currently unknown and requires further investigation.

Three-dimensional architecture of macrofibrils in the human scalp hair cortex.

Human scalp hairs are comprised of a central cortex enveloped by plate-like cuticle cells. The elongate cortex cells of mature fibres are composed primarily of macrofibrils-bundles of hard-keratin intermediate filaments (IFs) chemically cross-linked within a globular protein matrix. In wool, three cell types (ortho-, meso- and paracortex) contain macrofibrils with distinctly different filament arrangements and matrix fractions, but in human hair macrofibril-cell type relationships are less clear. Here we show that hair macrofibrils all have a similar matrix fraction (∼0.4) and are typically composed of a double-twist architecture in which a central IF is surrounded by concentric rings of tangentially-angled IFs. The defining parameter is the incremental angle increase (IF-increment) between IFs of successive rings. Unlike the wool orthocortex, hair double-twist macrofibrils have considerable inter-macrofibril variation in IF increment (0.05-0.35°/nm), and macrofibril size and IF increment are negatively correlated. Correspondingly, angular difference between central and outer-most IFs is up to 40° in small macrofibrils, but only 5-10° in large macrofibrils. Single cells were observed containing mixtures of macrofibrils with different diameters. These new observations advance our understanding of the nano-level and cell-level organisation of human hair, with implications for interpretation of structure with respect the potential roles of cortex cell types in defining the mechanical properties of hair.

Individuals departing non-breeding areas early achieve earlier breeding and higher breeding success.

Conditions experienced by an individual during migration have the potential to shape migratory tactic and in turn fitness. For large birds, environmental conditions encountered during migration have been linked with survival and subsequent reproductive output, but this is less known for smaller birds, hindering our understanding of mechanisms driving population change. By combining breeding and tracking data from 62 pied flycatchers (Ficedula hypoleuca) representing two breeding populations collected over 2016-2020, we determine how variation in migration phenology and tactic among individuals affects subsequent breeding. Departure date from West African non-breeding areas to European breeding grounds was highly variable among individuals and had a strong influence on migration tactic. Early departing individuals had longer spring migrations which included longer staging duration yet arrived at breeding sites and initiated breeding earlier than later departing individuals. Individuals with longer duration spring migrations and early arrival at breeding sites had larger clutches, and for males higher fledging success. We suggest that for pied flycatchers, individual carry-over effects may act through departure phenology from West Africa, and the associated spring migration duration, to influence reproduction. While our results confirm that departure date from non-breeding areas can be associated with breeding success in migratory passerines, we identify spring staging duration as a key component of this process.

Spectrum of artificial light at night drives impact of a diurnal species in insect food web.

Artificial light at night (ALAN) has become a profound form of global anthropogenic environmental change differing in from natural light regimes in intensity, duration, distribution and spectra. It is clear that ALAN impacts individual organisms, however, population level effects, particularly of spectral changes, remain poorly understood. Here we exposed experimental multigenerational aphid-parasitoid communities in the field to seven different light spectra at night ranging from 385 to 630 nm and compared responses to a natural day-night light regime. We found that while aphid population growth was initially unaffected by ALAN, parasitoid efficiency declined under most ALAN spectra, leading to reduced top-down control and higher aphid densities. These results differ from those previously found for white light, showing a strong impact on species' daytime performance. This highlights the importance of ALAN spectra when considering their environmental impact. ALAN can have large impacts on the wider ecological community by influencing diurnal species.

Experiments in Raman spectroscopy of hair: exciting light and molecular orientation.

Hair fibers have been analyzed by Raman spectroscopy to assess the suitability of a range of excitation wavelengths for data collection over extended periods of time. It is found that the optimum excitation wavelength for spectral detail, of these tested, was 780 nm and that this wavelength resulted in little signal degradation over time. It was found that with higher energy excitation sources that the signal intensity of the spectra degraded significantly in short periods of time. This work suggests that near-IR Raman spectroscopy therefore offers the most suitable conditions to analyze the nature of secondary structural feature in hair fibers. In addition, a preliminary exploration of the structural orientation of spectral features of the hair was attempted. Through the use of a linearly polarized excitation source the intensity of the Raman spectral features were observed to change as the alignment of the fiber axis with respect to the plane of polarization was changed. It was found that the spectral features associated with the alpha-helical vibrations decreased in intensity as the fiber axis was rotated from an orientation parallel to the exciting beam.

Fibre science: supercontraction stress in wet spider dragline.

Unrestrained spider dragline 'super-contracts' when it is wetted, causing its length to shrink by about half and its diameter to almost double. Here we measure the supercontraction stresses generated upon initial exposure of spider dragline to moisture and find that they are transient, as well as being greater than previously estimated. Our findings cast doubt on suggestions that supercontraction may help to maintain tension in wet webs and could limit the potential load-bearing applications of silk and its analogues.