24,984 research outputs found
What is the importance of sperm subpopulations?
.The study of sperm subpopulations spans three decades. The origin, meaning, and practical significance, however, are less clear. Current technology for assessing sperm morphology (CASA-Morph) and motility (CASA-Mot) has enabled the accurate evaluation of these features, and there are many options for data classification. Subpopulations could occur as a result of the stage of development of each spermatozoon in the subpopulation. Spermatogenesis might contribute to the production of these subpopulations. Insights from evolutionary biology and recent molecular research are indicative of the diversity among male gametes that could occur from unequal sharing of transcripts and other elements through cytoplasmic bridges between spermatids. Sperm cohorts exiting the gonads would contain different RNA and protein contents, affecting the spermatozoon physiology and associations with the surrounding environmental milieu. Subsequently, these differences could affect how spermatozoa interact with the environmental milieu (maturation, mixing with seminal plasma, and interacting with the environmental milieu, or female genital tract and female gamete). The emergence of sperm subpopulations as an outcome of evolution, related to the reproductive strategies of the species, genital tract structures, and copulatory and fertilization processes. This kind of approach in determining the importance of sperm subpopulations in fertilization capacity should have a practical impact for conducting reproductive technologies, inspiring and enabling new ways for the more efficient use of spermatozoa in the medical, animal breeding, and conservation fields. This manuscript is a contribution to the Special Issue in memory of Dr. Duane GarnerS
NFT-Related Companies: Token Sale Returns
Non-fungible tokens (NFTs) have emerged as a new means of digital asset ownership and many companies are building projects that revolve around the technology. These companies are blockchain-based and raise capital for their projects through cryptocurrency token sales, which have become a new mechanism of entrepreneurial finance. In a sample of 62 NFT-related companies, I examine which company, fundraising, and token sale process characteristics are associated with the performance of 7-day and 60-day market returns after a tokenâs public listing. A multivariate regression analysis finds that the total amount of capital raised before a token launch has a negative relationship with the 7-day and 60-day market returns. Ethereum returns, the length of the team token lock-up period and the presence of a vesting schedule have positive relationships with 60-day token returns
Identification of Hindbrain Neural Substrates for Motor Initiation in the hatchling Xenopus laevis Tadpole
Animal survival profoundly depends on the ability to detect stimuli in the environment, process them and respond accordingly. In this respect, motor responses to a sensory stimulation evolved into a variety of coordinated movements, which involve the control of brain centres over spinal locomotor circuits. The hatchling Xenopus tadpole, even in its embryonic stage, is able to detect external sensory information and to swim away if the stimulus is considered noxious. To do so, the tadpole relies on well-known ascending sensory pathway, which carries the sensory information to the brain. When the stimulus is strong enough, descending interneurons are activated, leading to the excitation of spinal CPG neurons, which causes the undulatory movement of swimming. However, the activation of descending interneurons that marks the initiation of motor response appears after a long delay from the sensory stimulation. Furthermore, the long-latency response is variable in time, as observed in the slow-summating excitation measured in descending interneurons. These two features, i.e. long-latency and variability, cannot be explained by the firing time and pattern of the ascending sensory pathway of the Xenopus tadpole. Therefore, a novel neuronal population has been proposed to lie in the hindbrain of the tadpole, and being able to 'hold' the sensory information, thus accounting for the long and variable delay of swim initiation. In this work, the role of the hindbrain in the maintenance of the long and variable response to trunk skin stimulation is investigated in the Xenopustadpole at developmental stage 37/38. A multifaceted approach has been used to unravel the neuronal mechanisms underlying the delayed motor response, including behavioural experiments, electrophysiology analysis of fictive swimming, hindbrain extracellular recordings and imaging experiments. Two novel neuronal populations have been identified in the tadpole's hindbrain, which exhibit activation patterns compatible with the role of delaying the excitation of the spinal locomotor circuit. Future work on cellular properties and synaptic connections of these newly discovered populations might shed light on the mechanism of descending control active at embryonic stage. Identifying supraspinal neuronal populations in an embryonic organism could aid in understanding mechanisms of descending motor control in more complex vertebrates
Interactive Sonic Environments: Sonic artwork via gameplay experience
The purpose of this study is to investigate the use of video-game technology in the design and implementation of interactive sonic centric artworks, the purpose of which is to create and contribute to the discourse and understanding of its effectiveness in electro-acoustic composition highlighting the creative process. Key research questions include: How can the language of electro-acoustic music be placed in a new framework derived from videogame aesthetics and technology? What new creative processes need to be considered when using this medium? Moreover, what aspects of 'play' should be considered when designing the systems? The findings of this study assert that composers and sonic art practitioners need little or no coding knowledge to create exciting applications and the myriad of options available to the composer when using video-game technology is limited only by imagination. Through a cyclic process of planning, building, testing and playing these applications the project revealed advantages and unique sonic opportunities in comparison to other sonic art installations. A portfolio of selected original compositions, both fixed and open are presented by the author to complement this study. The commentary serves to place the work in context with other practitioners in the field and to provide compositional approaches that have been taken
The influence of blockchains and internet of things on global value chain
Despite the increasing proliferation of deploying the Internet of Things (IoT) in global value chain (GVC), several challenges might lead to a lack of trust among value chain partners, e.g., technical challenges (i.e., confidentiality, authenticity, and privacy); and security challenges (i.e., counterfeiting, physical tempering, and data theft). In this study, we argue that Blockchain technology, when combined with the IoT ecosystem, will strengthen GVC and enhance value creation and capture among value chain partners. Thus, we examine the impact of Blockchain technology when combined with the IoT ecosystem and how it can be utilized to enhance value creation and capture among value chain partners. We collected data through an online survey, and 265 UK Agri-food retailers completed the survey. Our data were analyzed using structural equation modelling (SEM). Our finding reveals that Blockchain technology enhances GVC by improving IoT scalability, security, and traceability when combined with the IoT ecosystem. Which, in turn, strengthens GVC and creates more value for value chain partners â which serves as a competitive advantage. Finally, our research outlines the theoretical and practical contribution of combining Blockchain technology and the IoT ecosystem
Responding to research evidence in Parliament: a case study on selective education policy
This research focusses on how members of the UK Parliament engaged with evidence in relation to the policy decision leading to the Selective Schools Expansion Fund, a policy designed to enable the existing 163 English Grammar Schools to apply for additional funds to expand their intake. Although a small case study, the narrow focus provides a fertile setting for analysis of the relationship between research evidence, Parliamentary debates, and policy decisions. The article provides contextual background in relation to the dominant political partiesâ (Conservative and Labour) education policy manifesto statements and a discussion on the nature and understanding of evidence. Particular attention is given to how evidence can be used to support claims and the importance of justified warrants. Using NVivo software, we identified the thematic content of 11 Parliamentary debates and analysed the findings using descriptive statistics, which we tested with a playful, carnivalesque extrapolation of the data. Argumentative analysis shows that within the debates a number of rhetorical tools are used to avoid empirical evidence, including the deployment of a âmoral sidestepâ which discourse analysis reveals in this case to be the repeated communication that grammar schools are âgoodâ. In this way, Ofsted ratings are conflated with moral goodness, leading to a disproportionate diversion of school funding in their favour. This case study exposes strengths and weaknesses of Parliamentary debate, which might be relevant to educational researchers who focus on evidence-based policy and to the policy makers and other stakeholders who engage with the evidence such researchers offer
The company she keeps : The social and interpersonal construction of girls same sex friendships
This thesis begins a critical analysis of girls' 'private' interpersonal and social relations as they are enacted within two school settings. It is the study of these marginal subordinated worlds productivity of forms of femininity which provides the main narrative of this project. I seek to understand these processes of (best) friendship construction through a feminist multi-disciplinary frame, drawing upon cultural studies, psychoanalysis and accounts of gender politics. I argue that the investments girls bring to their homosocial alliances and boundary drawing narry a psychological compulsion which is complexly connected to their own experiences within the mother/daughter bond as well as reflecting positively an immense social debt to the permissions girls have to be nurturant and ; negatively their own reproduction of oppressive exclusionary practices. Best friendship in particular gives girls therefore, the experience of 'monogamy' continuous of maternal/daughter identification, reminiscent of their positioning inside monopolistic forms of heterosexuality. But these subcultures also represent a subversive discontinuity to the public dominance of boys/teachers/adults in schools and to the ideologies and practices of heterosociality and heterosexuality. By taking seriously their transmission of the values of friendship in their chosen form of notes and diaries for example, I was able to access the means whereby they were able to resist their surveillance and control by those in power over them. I conclude by arguing that it is through a recognition of the valency of these indivisiblly positive and negative aspects to girls cultures that Equal Opportunities practitioners must begin if they are serious about their ambitions. Methods have to be made which enable girls to transfer their 'private' solidarities into the 'public' realm, which unquestionably demands contesting with them the causes and consequences of their implication in the divisions which also contaminate their lives and weaken them
Reforming the United Nations
The thesis deals with the financial crisis that the United Nations faced starting in 1985 when the US Congress decided to withhold a significant part of the US contribution to the UN regular budget in order to force a greater say for the major contributors on budgetary issues, budgetary restraint and greater efficiency. The UN responded by the adoption of resolution 41/213 of 19 December 1986 that was based on the recommendations of a Group of High-level Intergovernmental Experts ("G-18") set up a year earlier. A new system was introduced regarding the formulation of the regular budget of the United Nations Organisation and a broader process of reform was initiated including a restructuring of the Secretariat and of the intergovernmental machinery in the economic and social fields. After an introductory chapter (Chapter I), the thesis examines the UN problems at the budgetary/financial and administrative/structural levels, the solutions proposed from within and without the United Nations established framework and the actual attempts at reform (Chapters II and ifi). The realisation that the implementation of reforms is rather disjointed and often unsuccessful (e.g. the failure to restructure the intergovernmental machi.neiy) prompts a search for the deeper causes of the UN problems at the political level and the attitudes of the main actors, namely the USA, the USSR, some up-and-coming states, notably Japan, the Third World states and, finally, of the UN Secretary-General and the Secretariat (Chapter 1V). Although the financial crisis may have subsided since 1988 and the USA seem committed to paying up their dues, the deeper UN crisis of identity has not been resolved and is expected to resurface if no bold steps are taken. In that direction, some possible alternative courses for the UN in the future are discussed drawing upon theory and practice (Chapte
Brain electrical traits of logical validity
p. 1-13Neuroscience has studied deductive reasoning over the last 20 years under the assumption that deductive inferences are not only de jure but also de facto distinct from other forms of inference. The objective of this research is to verify if logically valid deductions leave any cerebral electrical trait that is distinct from the trait left by non-valid deductions. 23 subjects with an average age of 20.35 years were registered with MEG and placed into a two conditions paradigm (100 trials for each condition) which each presented the exact same relational complexity (same variables and content) but had distinct logical complexity. Both conditions show the same electromagnetic components (P3, N4) in the early temporal window (250â525 ms) and P6 in the late temporal window (500â775 ms). The significant activity in both valid and invalid conditions is found in sensors from medial prefrontal regions, probably corresponding to the ACC or to the medial prefrontal cortex. The amplitude and intensity of valid deductions is significantly lower in both temporal windows (p = 0.0003). The reaction time was 54.37% slower in the valid condition. Validity leaves a minimal but measurable hypoactive electrical trait in brain processing. The minor electrical demand is attributable to the recursive and automatable character of valid deductions, suggesting a physical indicator of computational deductive properties. It is hypothesized that all valid deductions are recursive and hypoactive.S
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Using Digital Storytelling in Science: Meaning Making with Students aged 10-12 years old
Meaning making is an essential aspect of learning as a process of interpreting and negotiating information while sharing it with others. One way of meaning making is through (digital) storytelling. The process of creating and telling a story depends on how one can see their understanding of something come together and make sense and it is considered a (socio) constructivist strategy of learning. The purpose and contribution of this research are to explore how digital storytelling may support engagement in meaning-making as students externalise their understanding of the science topic of matter. To this aim, two digital storytelling activities were constructed â SEeDS (Sequencing of Events enabling Digital Storytelling) and Narration. The two activities included the same content but differed in structure. SEeDS presented the story scenes in an order that was not predefined and Narration in a predefined order. Both activities derived elements from the theoretical concept of Tricky Topics and Stumbling Blocks (SBs). This research was informed by the theory of Problem-based learning.
Participants were sixty-one Greek primary students aged 10-12 years old and twenty-two English secondary students aged 11-12 years old. Half students worked through the SEeDS activity and the rest through the Narration activity. Students worked cooperatively in small teams to implement the two activities. A systematic analysis of the collected data was conducted using qualitative methods. Findings revealed that the two activities had supported the Greek and English students in externalising their understanding of many scientific concepts included in the topic of matter, while it identified gaps in their prior knowledge. The two activities have also facilitated the instinctive use of exploratory talk over the other two types (cumulative and disputational talk) that can often be found in peer talk in science learning. Finally, the two activities appeared to have engaged students in the two contexts, as they allowed them to own the story creation whilst working independently. Finally, the Greek and English students viewed the SEeDS activity as challenging, making it hard to complete and at times tiring and confusing, and the Narration activity as easy to implement, giving students the opportunity to mainly focus on inventing the story plot.
This research makes a valuable contribution to the literature on making meaning in science, offering new insights about the use of problem-based stories supported by mobile technology. The findings provide opportunities to further explore the practical application of problem-based digital storytelling activities, which are hard thinking and challenging, across different age groups and cultural contexts. There is a need for teaching practices to be based on socio-constructivist learning approaches that focus on studentsâ thinking, not performance. Therefore, the implications of this research are relevant to a number of educational contexts and levels
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