4,895 research outputs found
Short CommunicationsFruit selection in the olive thrush: the importance of colour
Free-living olive thrushes Turdus olivaceus were offered a choice of wild olive Olea africana fruit of four colours, representing four ripeness categories. The thrushes ate mostly black fruit (ripest), followed by maroon (ripe) and olivecoloured (partially ripe) fruit. When riper fruit was unavailable, the thrushes selected more maroon or olive-coloured fruit. Green fruit (unripe) were never eaten, even when these were the only ones available. When offered pieces of dyed pear Pyrus communis, the thrushes preferentially selected orange pieces, followed by red and black pieces. Green pieces were never eaten. The results indicated that olive thrushes selectedfruit on the basis of fruit colour, and that colour preferences differed between the two types of fruit offered.S. Afr. J. Zool1997, 32(1
Morphology and Timing of Submarine Mass Movements on the Northwest British Continental Margin
A variety of factors influence the stability of submarine slopes and this thesis investigates those operating on the northwest British continental margin and Barra Fan. Through analysis of North Atlantic sector submarine mass movements, a conceptual model of continental slope failure is proposed and examined against the Peach slide case study. Situated on the eastern flank of the Rockall Trough, the Barra Fan is subject to cyclonic ocean circulation and has experienced growth since continental uplift during the mid-Pliocene. Surface and shallow-subsurface morphology of the fan is determined using pinger sub-bottom profile (paper records scanned and converted to SEGY format), sidescan sonar and multibeam echosounder data. A number of different acoustic facies are mapped, including: contourites, hemipelagites and debris flows. Analysis of gravity core 56/-10/239 identifies a debris flow containing material of glacial age and AMS ¹⁴C dating of planktonic foraminifera constrain emplacement prior to 11.9 ka cal BP. Reference to additional sediment cores located in the Barra Fan region (MD95-2006 and 56/-10/36) allows the development of a chronology for the contourites and hemipelagites interpreted during geophysical investigation. This allows constraint of two periods of slope failure during the late Pleistocene: the first between 21 and 20 ka cal BP, shortly after the British ice sheetʼs maximum advance; and the second between 12 and 11 ka cal BP at the termination of the Younger Dryas stadial. Processes similar to those on the Norwegian continental margin seem to operate on the northwest British continental margin, the morphology and setting of the Peach slide is similar to Storegga and Trænadjupet, suggesting that similar processes initiated failure. Important roles seem to be played by contouritic and glaciogenic sedimentation, producing excess pore pressure in the fanʼs sediments with fluid expulsion visible in the acoustic data
From Transcriptomics to Treatment in Inherited Optic Neuropathies
Inherited optic neuropathies, including Leber Hereditary Optic Neuropathy (LHON) and Dominant Optic Atrophy (DOA), are monogenetic diseases with a final common pathway of mitochondrial dysfunction leading to retinal ganglion cell (RGC) death and ultimately loss of vision. They are, therefore, excellent models with which to investigate this ubiquitous disease process—implicated in both common polygenetic ocular diseases (e.g., Glaucoma) and late-onset central nervous system neurodegenerative diseases (e.g., Parkinson disease). In recent years, cellular and animal models of LHON and DOA have matured in parallel with techniques (such as RNA-seq) to determine and analyze the transcriptomes of affected cells. This confluence leaves us at a particularly exciting time with the potential for the identification of novel pathogenic players and therapeutic targets. Here, we present a discussion of the importance of inherited optic neuropathies and how transcriptomic techniques can be exploited in the development of novel mutation-independent, neuroprotective therapies
Radial Evolution of Sunward Strahl Electrons in the Inner Heliosphere
The heliospheric magnetic field (HMF) exhibits local inversions, in which the field apparently “bends back” upon itself. Candidate mechanisms to produce these inversions include various configurations of upstream interchange reconnection; either in the heliosphere, or in the corona where the solar wind is formed. Explaining the source of these inversions, and how they evolve in time and space, is thus an important step towards explaining the origins of the solar wind. Inverted heliospheric magnetic field lines can be identified by the anomalous sunward (i.e. inward) streaming of the typically anti-sunward propagating, field-aligned (or anti-aligned), beam of electrons known as the “strahl”. We test if the pitch angle distribution (PAD) properties of sunward-propagating strahl are different from those of outward strahl. We perform a statistical study of strahl observed by the Helios spacecraft, over heliocentric distances spanning ≈0.3 – 1 AU. We find that sunward strahl PADs are broader and less intense than their outward directed counterparts; particularly at distances 0.3 – 0.75 AU. This is consistent with sunward strahl being subject to additional, path-length dependent, scattering in comparison to outward strahl. We conclude that the longer and more variable path from the Sun to the spacecraft, along inverted magnetic field, leads to this additional scattering. The results also suggest that the relative importance of scattering along this additional path length drops off with heliocentric distance. These results can be explained by a relatively simple, constant-rate, scattering process
Protein kinase C epsilon is required for macrophage activation and defense against bacterial infection
Imperial Cancer Research Fund, and grants FEDER 2FD-1997-1432 from Comisión Interministerial
de Ciencia y Tecnología (CICYT) and PM98-0120 from Dirección General de Enseñanza Superior e Investigación Científica, Spain. F. Otto was supported by Deutsche Forschungsgemeinschaft
grant Ot 134/1-1
Is translation semantically mediated? Evidence from Welsh-English bilingual aphasia
The involvement of the semantic system in picture naming is undisputed. However, it has been proposed that translation could take place via direct lexical links between L1 and L2 word forms in addition to or instead of via semantics(i.e., with translation going from a spoken word in L1 accessing its meaning and this meaning then leading to the retrieval of the translation equivalent in L2). There is conflicting evidence in the psycholinguistic literature as to the extent of semantic mediation in translation vs. picture naming tasks (Potter et al, 1984; Kroll and Stewart, 1994). More recently, Hernandez et al (2010) investigated this question in a case study of JFF, a proficient bilingual Spanish-Catalan speaker with Alzheimer’s disease and naming difficulties due to a semantic deficit. As JFF’s semantic deficit did not only affect picture naming but also translation tasks, the authors concluded against the existence of functional direct lexical links to support translation. The goal of our study was to explore this issue further in a larger sample of proficient bilingual patients with aphasia and word finding difficulties in both languages. More specifically, we compare the rate of semantic errors produced in naming vs. translation tasks
4-dimensional functional profiling in the convulsant-treated larval zebrafish brain
This is the final version of the article. Available from Springer Nature via the DOI in this record.Functional neuroimaging, using genetically-encoded Ca(2+) sensors in larval zebrafish, offers a powerful combination of high spatiotemporal resolution and higher vertebrate relevance for quantitative neuropharmacological profiling. Here we use zebrafish larvae with pan-neuronal expression of GCaMP6s, combined with light sheet microscopy and a novel image processing pipeline, for the 4D profiling of chemoconvulsant action in multiple brain regions. In untreated larvae, regions associated with autonomic functionality, sensory processing and stress-responsiveness, consistently exhibited elevated spontaneous activity. The application of drugs targeting different convulsant mechanisms (4-Aminopyridine, Pentylenetetrazole, Pilocarpine and Strychnine) resulted in distinct spatiotemporal patterns of activity. These activity patterns showed some interesting parallels with what is known of the distribution of their respective molecular targets, but crucially also revealed system-wide neural circuit responses to stimulation or suppression. Drug concentration-response curves of neural activity were identified in a number of anatomically-defined zebrafish brain regions, and in vivo larval electrophysiology, also conducted in 4dpf larvae, provided additional measures of neural activity. Our quantification of network-wide chemoconvulsant drug activity in the whole zebrafish brain illustrates the power of this approach for neuropharmacological profiling in applications ranging from accelerating studies of drug safety and efficacy, to identifying pharmacologically-altered networks in zebrafish models of human neurological disorders.This work was funded by the Biological and Biotechnology Research Council (CASE studentship BB/L502510/1, with AstraZeneca Safety Health and Environment), and by the University of Exeter and AstraZeneca
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Genome-wide screening of mouse knockouts reveals novel genes required for normal integumentary and oculocutaneous structure and function.
Oculocutaneous syndromes are often due to mutations in single genes. In some cases, mouse models for these diseases exist in spontaneously occurring mutations, or in mice resulting from forward mutatagenesis screens. Here we present novel genes that may be causative for oculocutaneous disease in humans, discovered as part of a genome-wide screen of knockout-mice in a targeted single-gene deletion project. The International Mouse Phenotyping Consortium (IMPC) database (data release 10.0) was interrogated for all mouse strains with integument abnormalities, which were then cross-referenced individually to identify knockouts with concomitant ocular abnormalities attributed to the same targeted gene deletion. The search yielded 307 knockout strains from unique genes with integument abnormalities, 226 of which have not been previously associated with oculocutaneous conditions. Of the 307 knockout strains with integument abnormalities, 52 were determined to have ocular changes attributed to the targeted deletion, 35 of which represent novel oculocutaneous genes. Some examples of various integument abnormalities are shown, as well as two examples of knockout strains with oculocutaneous phenotypes. Each of the novel genes provided here are potentially relevant to the pathophysiology of human integumentary, or oculocutaneous conditions, such as albinism, phakomatoses, or other multi-system syndromes. The novel genes reported here may implicate molecular pathways relevant to these human diseases and may contribute to the discovery of novel therapeutic targets
Garden varieties: how attractive are recommended garden plants to butterflies?
One way the public can engage in insect conservation is through wildlife gardening, including the growing of insect-friendly flowers as sources of nectar. However, plant varieties differ in the types of insects they attract. To determine which garden plants attracted which butterflies, we counted butterflies nectaring on 11 varieties of summer-flowering garden plants in a rural garden in East Sussex, UK. These plants were all from a list of 100 varieties considered attractive to British butterflies, and included the five varieties specifically listed by the UK charity Butterfly Conservation as best for summer nectar. A total of 2659 flower visits from 14 butterfly and one moth species were observed. We performed a principal components analysis which showed contrasting patterns between the species attracted to Origanum vulgare and Buddleia davidii. The “butterfly bush” Buddleia attracted many nymphalines, such as the peacock, Inachis io, but very few satyrines such as the gatekeeper, Pyronia tithonus, which mostly visited Origanum. Eupatorium cannibinum had the highest Simpson’s Diversity score of 0.75, while Buddleia and Origanum were lower, scoring 0.66 and 0.50 respectively. No one plant was good at attracting all observed butterfly species, as each attracted only a subset of the butterfly community. We conclude that to create a butterfly-friendly garden, a variety of plant species are required as nectar sources for butterflies. Furthermore, garden plant recommendations can probably benefit from being more precise as to the species of butterfly they attract
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