2,690 research outputs found
The Eye's mind - Visual imagination, neuroscience and the humanities
This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordThis work was supported by funding from the Arts and Humanities Research Council through a Science in Culture Innovation Award: The Eye's Mind – a study of the neural basis of visual imagination and of its role in culture (Reference AH/M002756/1)
Matrilineal inheritance of a key mediator of prenatal maternal effects
This is the author accepted manuscript. The final version is available from the Royal Society via the DOI in this record.Sex-linkage is predicted to evolve in response to sex-specific or sexually antagonistic selection. In line with this prediction, most sex-linked genes are associated with reproduction in the respective sex. In addition to traits directly involved in fertility and fecundity, mediators of maternal effects may be predisposed to evolve sex-linkage, because they indirectly affect female fitness through their effect on offspring phenotype. Here, we test for sex-linked inheritance of a key mediator of prenatal maternal effects in oviparous species, the transfer of maternally derived testosterone to the eggs. Consistent with maternal inheritance, we found that in Japanese quail (Coturnix japonica) granddaughters resemble their maternal (but not their paternal) grandmother in yolk testosterone deposition. This pattern of resemblance was not due to non-genetic priming effects of testosterone exposure during prenatal development, as an experimental manipulation of yolk testosterone levels did not affect the females' testosterone transfer to their own eggs later in life. Instead, W chromosome and/or mitochondrial variation may underlie the observed matrilineal inheritance pattern. Ultimately, the inheritance of mediators of maternal effects along the maternal line will allow for a fast and direct response to female-specific selection, thereby affecting the dynamics of evolutionary processes mediated by maternal effects.The study was financially supported by Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung (PP00P3_128386 and PP00P3_157455) and Fonds zur Förderung des akademischen Nachwuchses (FAN)
In ovo yolk carotenoid and testosterone levels interactively influence female transfer of yolk antioxidants to her eggs
This is the author accepted manuscript. The final version is available from the Royal Society via the DOI in this recordMothers can influence prenatal conditions by varying the amount of nutrients, hormones or antioxidants they provide to their developing young. Some of these substances even affect the transfer of these compounds in the next generation, but it is less clear how different maternally transmitted compounds interact with each other to shape reproductive resource allocation in their offspring. Here, we found that female Japanese quail that were exposed to high carotenoid levels during embryonic development transferred lower concentrations of yolk antioxidants to their own eggs later in life. This effect disappeared, when both testosterone and carotenoid concentrations were manipulated simultaneously, showing long-term and interactive effects of these maternally derived egg components on a female’s own egg composition. Given that exposure to high levels of testosterone during embryo development stimulates the production of reactive oxygen (ROS) and impairs antioxidant defenses, we propose that carotenoids act as in-ovo antioxidants in an oxidatively stressful environment (i.e. when levels of testosterone are high) but might have prooxidant properties in an environment where they are not used to counteract an increased production of ROS. In line with this hypothesis, we previously showed that prenatal exposure to increased concentrations of yolk carotenoids leads to a rise of oxidative damage at adulthood, but only when yolk testosterone concentrations were not experimentally increased as well. As a consequence, antioxidants in the body may be used to limit oxidative damage in females exposed to high levels of carotenoids during development (but not in females exposed to increased levels of both carotenoids and testosterone), resulting in lower amounts of antioxidants being available for deposition into eggs. Since prenatal antioxidant exposure is known to influence fitness-related traits, the effect detected in this study might have transgenerational consequences.The study was supported by the Swiss National Science Foundation (PP00P3_128386 and
PP00P3_157455) and the Fonds zur Förderung des akademischen Nachwuchses
A competitive comparison of different types of evolutionary algorithms
This paper presents comparison of several stochastic optimization algorithms
developed by authors in their previous works for the solution of some problems
arising in Civil Engineering. The introduced optimization methods are: the
integer augmented simulated annealing (IASA), the real-coded augmented
simulated annealing (RASA), the differential evolution (DE) in its original
fashion developed by R. Storn and K. Price and simplified real-coded
differential genetic algorithm (SADE). Each of these methods was developed for
some specific optimization problem; namely the Chebychev trial polynomial
problem, the so called type 0 function and two engineering problems - the
reinforced concrete beam layout and the periodic unit cell problem
respectively. Detailed and extensive numerical tests were performed to examine
the stability and efficiency of proposed algorithms. The results of our
experiments suggest that the performance and robustness of RASA, IASA and SADE
methods are comparable, while the DE algorithm performs slightly worse. This
fact together with a small number of internal parameters promotes the SADE
method as the most robust for practical use.Comment: 25 pages, 8 figures, 5 table
How do older people discuss their own sexuality? A systematic review of qualitative research studies
This study captured older people’s attitudes and concerns about sex and sexuality in later life by synthesising qualitative research published on this issue. The systematic review was conducted between November 2015 and June 2016 based on a pre-determined protocol. Key words were used to ensure a precise search strategy. Empirically based, qualitative literature from 18 databases was found. Twenty studies met the inclusion criteria. Thomas and Harden’s thematic synthesis was used to generate ‘analytical themes’ which summarise this body of literature. Three main themes were identified: (a) social legitimacy for sexuality in later life; (b) health, not age, is what truly impacts sexuality, and (c) the hegemony of penetrative sex. The themes illustrate the complex and delicate relation between ageing and sexuality. Older adults facing health issues that affect sexual function adopt broader definitions of sexuality and sexual activit
Microstructural enrichment functions based on stochastic Wang tilings
This paper presents an approach to constructing microstructural enrichment
functions to local fields in non-periodic heterogeneous materials with
applications in Partition of Unity and Hybrid Finite Element schemes. It is
based on a concept of aperiodic tilings by the Wang tiles, designed to produce
microstructures morphologically similar to original media and enrichment
functions that satisfy the underlying governing equations. An appealing feature
of this approach is that the enrichment functions are defined only on a small
set of square tiles and extended to larger domains by an inexpensive stochastic
tiling algorithm in a non-periodic manner. Feasibility of the proposed
methodology is demonstrated on constructions of stress enrichment functions for
two-dimensional mono-disperse particulate media.Comment: 27 pages, 12 figures; v2: completely re-written after the first
revie
The effect of tumour necrosis factor-α (TNF-α) muteins on human neutrophils in vitro
Tumour necrosis factor-α (TNF-α) has been implicated as an important inflammatory mediator. In vitro, TNF-α is reported to activate human polymorphonuclear neutrophils (PMN), inducing responses such as phagocytic activity, degranulation and oxidative metabolism. Biological responses to TNF-α are initiated by its binding to specific cell surface receptors, and various studies have shown that the major TNF receptor species on PMN is the 75 kDa receptor. To verify the suggestion that the receptor binding domain includes the region close to the N-terminus of the TNF-α molecule, four TNF-α derivatives termed muteins were constructed, using a synthetic cDNA fragment substituting the N-terminal 3–7 selected hydrophilic or hydrophobic amino acids in the original TNF-α genomic DNA. Binding of muteins to PMN was assessed using monoclonal antibodies recognizing either the 55 kDa (p55) or the 75 kDa (p75) TNF receptor subtypes. Blocking by muteins of anti-p75 antibody binding to PMN was as expected from their N-terminal amino acid composition and hydrophilic properties. Hydrophilic muteins competed well with anti-TNF receptor antibodies for binding to the p75 receptor. In contrast, hydrophobic muteins were unable to block anti-p75 binding. Similarly, degranulation, chemiluminescence or enhancement of the PMN response to specific stimuli by the muteins correlated with the hydrophilic properties of the muteins. The significance of these observations in relation to the molecular structure of TNF-α is discussed
- …