1,042 research outputs found
Interaction of snow management × N & P fertilizer and their effect on spring wheat yields
Non-Peer Reviewe
Citizen science in environmental protection agencies
Citizen science, the active participation of the public in scientific research projects, is a rapidly expanding field in open science and open innovation. It provides an integrated model of public knowledge production and engagement with science. As a growing worldwide phenomenon, it is invigorated by evolving new technologies that connect people easily and effectively with the scientific community. Catalysed by citizens’ wishes to be actively involved in scientific processes, as a result of recent societal trends, it also offers contributions to the rise in tertiary education. In addition, citizen science provides a valuable tool for citizens to play a more active role in sustainable development.
This book identifies and explains the role of citizen science within innovation in science and society, and as a vibrant and productive science-policy interface. The scope of this volume is global, geared towards identifying solutions and lessons to be applied across science, practice and policy. The chapters consider the role of citizen science in the context of the wider agenda of open science and open innovation, and discuss progress towards responsible research and innovation, two of the most critical aspects of science today
Decay of quantised vorticity by sound emission
It is thought that in a quantum fluid sound generation is the ultimate sink
of turbulent kinetic energy in the absence of any other dissipation mechanism
near absolute zero. We show that a suitably trapped Bose-Einstein condensate
provides a model system to study the sound emitted by accelerating vortices in
a controlled way.Comment: 6 pages, 3 figure
DNA induces conformational changes in a recombinant human minichromosome maintenance complex
ATP-dependent DNA unwinding activity has been demonstrated for recombinant archaeal homohexameric minichromosome maintenance (MCM) complexes and their yeast heterohexameric counterparts, but in higher eukaryotes such as Drosophila, MCM-associated DNA helicase activity has only been observed in the context of a co-purified Cdc45-MCM-GINS (CMG) complex. Here we describe the production of recombinant human MCM complex (hMCM) in E. coli. This protein displays ATP hydrolysis activity and is capable of unwinding duplex DNA. Using single particle asymmetric electron microscopy reconstruction, we demonstrate recombinant hMCM forms a hexamer that undergoes a conformational change when bound to DNA. Recombinant hMCM produced without post-translational modifications is functional in vitro and provides an important tool for the biochemical reconstitution of the human replicative helicase
AMPK activation protects from neuronal dysfunction and vulnerability across nematode, cellular and mouse models of Huntington's disease.
The adenosine monophosphate activated kinase protein (AMPK) is an evolutionary-conserved protein important for cell survival and organismal longevity through the modulation of energy homeostasis. Several studies suggested that AMPK activation may improve energy metabolism and protein clearance in the brains of patients with vascular injury or neurodegenerative disease. However, in Huntington's disease (HD), AMPK may be activated in the striatum of HD mice at a late, post-symptomatic phase of the disease, and high-dose regiments of the AMPK activator 5-aminoimidazole-4-carboxamide ribonucleotide may worsen neuropathological and behavioural phenotypes. Here, we revisited the role of AMPK in HD using models that recapitulate the early features of the disease, including Caenorhabditis elegans neuron dysfunction before cell death and mouse striatal cell vulnerability. Genetic and pharmacological manipulation of aak-2/AMPKα shows that AMPK activation protects C. elegans neurons from the dysfunction induced by human exon-1 huntingtin (Htt) expression, in a daf-16/forkhead box O-dependent manner. Similarly, AMPK activation using genetic manipulation and low-dose metformin treatment protects mouse striatal cells expressing full-length mutant Htt (mHtt), counteracting their vulnerability to stress, with reduction of soluble mHtt levels by metformin and compensation of cytotoxicity by AMPKα1. Furthermore, AMPK protection is active in the mouse brain as delivery of gain-of-function AMPK-γ1 to mouse striata slows down the neurodegenerative effects of mHtt. Collectively, these data highlight the importance of considering the dynamic of HD for assessing the therapeutic potential of stress-response targets in the disease. We postulate that AMPK activation is a compensatory response and valid approach for protecting dysfunctional and vulnerable neurons in HD
Lesbian and bisexual women's human rights, sexual rights and sexual citizenship: negotiating sexual health in England.
Lesbian and bisexual women's sexual health is neglected in much Government policy and practice in England and Wales. This paper examines lesbian and bisexual women's negotiation of sexual health, drawing on findings from a small research project. Themes explored include invisibility and lack of information, influences on decision-making and sexual activities and experiences of services and barriers to sexual healthcare. Key issues of importance in this respect are homophobic and heterosexist social contexts. Drawing on understandings of lesbian, gay and bisexual human rights, sexual rights and sexual citizenship, it is argued that these are useful lenses through which to examine and address lesbian and bisexual women's sexual health and related inequalities
Rapid destruction of protoplanetary discs due to external photoevaporation in star-forming regions
We analyse N-body simulations of star-forming regions to investigate the effects of external far- and extreme-ultraviolet photoevaporation from massive stars on protoplanetary discs. By varying the initial conditions of simulated star-forming regions, such as the spatial distribution, net bulk motion (virial ratio), and density, we investigate which parameters most affect the rate at which discs are dispersed due to external photoevaporation. We find that disc dispersal due to external photoevaporation is faster in highly substructured star-forming regions than in smooth and centrally concentrated regions. Subvirial star-forming regions undergoing collapse also show higher rates of disc dispersal than regions that are in virial equilibrium or are expanding. In moderately dense (∼100 M⊙ pc−3) regions, half of all protoplanetary discs with radii ≥100 au are photoevaporated within 1 Myr, three times faster than is currently suggested by observational studies. Discs in lower density star-forming regions (∼10 M⊙ pc−3) survive for longer, but half are still dispersed on short time-scales (∼2 Myr). This demonstrates that the initial conditions of the star-forming regions will greatly impact the evolution and lifetime of protoplanetary discs. These results also imply that either gas giant planet formation is extremely rapid and occurs before the gas component of discs is evaporated, or gas giants only form in low-density star-forming regions where no massive stars are present to photoevaporate gas from protoplanetary discs
Stochastic Theory of Accelerated Detectors in a Quantum Field
We analyze the statistical mechanical properties of n-detectors in arbitrary
states of motion interacting with each other via a quantum field. We use the
open system concept and the influence functional method to calculate the
influence of quantum fields on detectors in motion, and the mutual influence of
detectors via fields. We discuss the difference between self and mutual
impedance and advanced and retarded noise. The mutual effects of detectors on
each other can be studied from the Langevin equations derived from the
influence functional, as it contains the backreaction of the field on the
system self-consistently. We show the existence of general fluctuation-
dissipation relations, and for trajectories without event horizons,
correlation-propagation relations, which succinctly encapsulate these quantum
statistical phenomena. These findings serve to clarify some existing confusions
in the accelerated detector problem. The general methodology presented here
could also serve as a platform to explore the quantum statistical properties of
particles and fields, with practical applications in atomic and optical physics
problems.Comment: 32 pages, Late
Making things happen : a model of proactive motivation
Being proactive is about making things happen, anticipating and preventing problems, and seizing opportunities. It involves self-initiated efforts to bring about change in the work environment and/or oneself to achieve a different future. The authors develop existing perspectives on this topic by identifying proactivity as a goal-driven process involving both the setting of a proactive goal (proactive goal generation) and striving to achieve that proactive goal (proactive goal striving). The authors identify a range of proactive goals that individuals can pursue in organizations. These vary on two dimensions: the future they aim to bring about (achieving a better personal fit within one’s work environment, improving the organization’s internal functioning, or enhancing the organization’s strategic fit with its environment) and whether the self or situation is being changed. The authors then identify “can do,” “reason to,” and “energized to” motivational states that prompt proactive goal generation and sustain goal striving. Can do motivation arises from perceptions of self-efficacy, control, and (low) cost. Reason to motivation relates to why someone is proactive, including reasons flowing from intrinsic, integrated, and identified motivation. Energized to motivation refers to activated positive affective states that prompt proactive goal processes. The authors suggest more distal antecedents, including individual differences (e.g., personality, values, knowledge and ability) as well as contextual variations in leadership, work design, and interpersonal climate, that influence the proactive motivational states and thereby boost or inhibit proactive goal processes. Finally, the authors summarize priorities for future researc
Fluctuations and Dissipation of Coherent Magnetization
A quantum mechanical model is used to derive a generalized Landau-Lifshitz
equation for a magnetic moment, including fluctuations and dissipation. The
model reproduces the Gilbert-Brown form of the equation in the classical limit.
The magnetic moment is linearly coupled to a reservoir of bosonic degrees of
freedom. Use of generalized coherent states makes the semiclassical limit more
transparent within a path-integral formulation. A general
fluctuation-dissipation theorem is derived. The magnitude of the magnetic
moment also fluctuates beyond the Gaussian approximation. We discuss how the
approximate stochastic description of the thermal field follows from our
result. As an example, we go beyond the linear-response method and show how the
thermal fluctuations become anisotropy-dependent even in the uniaxial case.Comment: 22 page
- …