3,416 research outputs found

    Efficient Sensor Deployments for Spatio-Temporal Environmental Monitoring

    Full text link
    IEEE This paper addresses the problem of efficiently deploying sensors in spatial environments, e.g., buildings, for the purposes of monitoring spatio-temporal environmental phenomena. By modeling the environmental fields using spatio-temporal Gaussian processes, a new and efficient optimality-cost function of minimizing prediction uncertainties is proposed to find the best sensor locations. Though the environmental processes spatially and temporally vary, the proposed approach of choosing sensor positions is proven not to be affected by time variations, which significantly reduces computational complexity of the optimization problem. The sensor deployment optimization problem is then solved by a practical and feasible polynomial algorithm, where its solutions are theoretically proven to be guaranteed. The proposed method is also theoretically and experimentally compared with the existing works. The effectiveness of the proposed algorithm is demonstrated by implementation in a real tested space in a university building, where the obtained results are highly promising

    Polarised radiative transfer, rotation measure fluctuations and large-scale magnetic fields

    Get PDF
    Faraday rotation measure at radio wavelengths is commonly used to diagnose large-scale magnetic fields. It is argued that the length-scales on which magnetic fields vary in large-scale diffuse astrophysical media can be inferred from correlations in the observed RM. RM is a variable which can be derived from the polarised radiative transfer equations in restrictive conditions. This paper assesses the usage of RMF (rotation measure fluctuation) analyses for magnetic field diagnostics in the framework of polarised radiative transfer. We use models of various magnetic field configurations and electron density distributions to show how density fluctuations could affect the correlation length of the magnetic fields inferred from the conventional RMF analyses. We caution against interpretations of RMF analyses when a characteristic density is ill-defined, e.g. in cases of log-normal distributed and fractal-like density structures. As the spatial correlations are generally not the same in the line-of-sight longitudinal direction and the sky plane direction, one also needs to clarify the context of RMF when inferring from observational data. In complex situations, a covariant polarised radiative transfer calculation is essential to capture all aspects of radiative and transport processes, which would otherwise ambiguate the interpretations of magnetism in galaxy clusters and larger-scale cosmological structures

    Barriers to innovation and sustainability at universities around the world

    Get PDF
    This paper explores the link between innovation and sustainability in the context of higher education, with the purpose of investigating the fundamental barriers for innovation and sustainable development in universities around the world. The method used involves both a quantitative and a qualitative approach, gathering the views of 301 experts from 172 universities across all continents. The results show that there are similar barriers across different geographical regions that require greater support from university administrations and management. In particular, the willingness of leaders, policy makers and decision-makers to envisage a sustainable future inside universities is often missing. Yet, without the support of senior management within a university, bottom-up sustainable initiatives seem destined to fail in the longer term due to a lack of investment and administrative support. This study also identifies that in order to yield the anticipated benefits, barriers need to be tackled in an integrated way, and that closer cooperation between sustainability researchers, university administrations and students is needed

    Power-free water pump based on a superhydrophobic surface: generation of a mushroom-like jet and anti-gravity long-distance transport

    Get PDF
    Spontaneous anti-gravitational transportation of liquids across long distances has been widely discovered in nature, such as water transportation from the root to the crown of a tree. However, artificial liquid delivery remains a challenge. In this work, a new power-free pump composed of a superhydrophobic plate with a pore mounted on a leak-proof cylindrical container filled with water is presented for sustained anti-gravity and long distance transport. Water droplets can be spontaneously captured through the pore by the lower water column, forming a mushroom-like jet due to the energy transition from surface energy to kinetic energy. The spontaneously increased inside pressure in the container will push the water out, through another thin tube, realizing the energy transition from surface energy to gravitational potential energy. The dynamic driving and moving model of the pivotal mushroom-like jet were analyzed. The maximum transport height and transport abilities of the water pump were also discussed. The results show that Laplace pressure is the main driving pressure of the mushroom-like jet and that the developed power-free pump can effectively transport water to over 100 mm in height with an average transport speed of 4500 μL h−1, showing potential for application in microfluidic systems and medical devices where micropumps are needed

    Taking stock of nature: Essential biodiversity variables explained

    Get PDF
    In 2013, the Group on Earth Observations Biodiversity Observation Network (GEO BON) developed the framework of Essential Biodiversity Variables (EBVs), inspired by the Essential Climate Variables (ECVs). The EBV framework was developed to distill the complexity of biodiversity into a manageable list of priorities and to bring a more coordinated approach to observing biodiversity on a global scale. However, efforts to address the scientific challenges associated with this task have been hindered by diverse interpretations of the definition of an EBV. Here, the authors define an EBV as a critical biological variable that characterizes an aspect of biodiversity, functioning as the interface between raw data and indicators. This relationship is clarified through a multi-faceted stock market analogy, drawing from relevant examples of biodiversity indicators that use EBVs, such as the Living Planet Index and the UK Spring Index. Through this analogy, the authors seek to make the EBV concept accessible to a wider audience, especially to non-specialists and those in the policy sector, and to more clearly define the roles of EBVs and their relationship with biodiversity indicators. From this we expect to support advancement towards globally coordinated measurements of biodiversity

    From E-MAPs to module maps: dissecting quantitative genetic interactions using physical interactions

    Get PDF
    Recent technological breakthroughs allow the quantification of hundreds of thousands of genetic interactions (GIs) in Saccharomyces cerevisiae. The interpretation of these data is often difficult, but it can be improved by the joint analysis of GIs along with complementary data types. Here, we describe a novel methodology that integrates genetic and physical interaction data. We use our method to identify a collection of functional modules related to chromosomal biology and to investigate the relations among them. We show how the resulting map of modules provides clues for the elucidation of function both at the level of individual genes and at the level of functional modules

    Stress responsive miR-31 is a major modulator of mouse intestinal stem cells during regeneration and tumorigenesis

    Get PDF
    Intestinal regeneration and tumorigenesis are believed to be driven by intestinal stem cells (ISCs). Elucidating mechanisms underlying ISC activation during regeneration and tumorigenesis can help uncover the underlying principles of intestinal homeostasis and disease including colorectal cancer. Here we show that miR-31 drives ISC proliferation, and protects ISCs against apoptosis, both during homeostasis and regeneration in response to ionizing radiation injury. Furthermore, miR-31 has oncogenic properties, promoting intestinal tumorigenesis. Mechanistically, miR-31 acts to balance input from Wnt, BMP, TGFb signals to coordinate control of intestinal homeostasis, regeneration and tumorigenesis. We further find that miR-31 is regulated by the STAT3 signaling pathway in response to radiation injury. These findings identify miR-31 as a critical modulator of ISC biology, and a potential therapeutic target for a broad range of intestinal regenerative disorders and cancers

    Síndrome de dermatitis y nefropatía porcino: una revisión sobre su epidemiología, patología y etiología

    Get PDF
    Porcine dermatitis and nephropathy syndrome (PDNS) is a disease that affects growing and finishing pigs characterized by a sporadic presentation, prevalence lower than 1 % and variable lethality. PDNS affected pigs shows acute multifocal red-to-purple skin lesions and enlarged tan kidneys with petechial hemorrhages. The hallmark microscopic lesions of PDNS are a generalized vasculitis and glomerulonephritis that suggest a type III hypersensitivity reaction. Although the etiology remains unknown, different works have showed the association between porcine circovirus type 2 (PCV-2) and PDNS based on epidemiological evidences, microscopic lesions and, the inconstant detection of PCV-2 antigen and / or nucleic acid in affected tissues. In this article the main characteristics of the disease from an epidemiological, pathological and etiological standpoint are described. Information about national situation is also included.El síndrome de dermatitis y nefropatía porcino (SDNP) es una entidad exclusiva de los cerdos que afecta, en general, a animales de desarrollo y engorde. Su presentación suele ser esporádica con una prevalencia en las granjas afectadas menor al 1% y una letalidad entre el 50 y 100% que varia según la edad. Se caracteriza por la aparición súbita de lesiones multifocales rojo-violáceas en piel y riñones pálidos que se cubren de hemorragias petequiales. La lesión microscópica típica consiste en una vasculitis generalizada y glomérulonefritis sugestivas de una reacción de hipersensibilidad tipo III, mediada por inmunocomplejos. Si bien su etiología no es conocida, distintos trabajos asocian al SDNP con la infección por circovirus porcino tipo 2 (PCV-2) basados en ciertas evidencias epidemiológicas, las características de algunas de las lesiones microscópicas y, aún cuando inconstante, la detección de antígeno y/o ácido nucleico de PCV-2 en tejidos de animales enfermos. En el presente trabajo se describen las principales características de la enfermedad desde el punto de vista de su epidemiología, patología y etiología, incluyendo datos sobre la situación en la Argentina
    corecore