4,002 research outputs found
Fast Compressive 3D Single-pixel Imaging
In this work, we demonstrate a modified photometric stereo system with perfect pixel
registration, capable of reconstructing continuous real-time 3D video at ~8 Hz for 64 x 64 image resolution by employing evolutionary compressed sensing
Nuclear processes associated with plant immunity and pathogen susceptibility
Plants are sessile organisms that have evolved exquisite and sophisticated mechanisms to adapt to their biotic and abiotic environment. Plants deploy receptors and vast signalling networks to detect, transmit and respond to a given biotic threat by inducing properly dosed defence responses. Genetic analyses and, more recently, next-generation -omics approaches have allowed unprecedented insights into the mechanisms that drive immunity. Similarly, functional genomics and the emergence of pathogen genomes have allowed reciprocal studies on the mechanisms governing pathogen virulence and host susceptibility, collectively allowing more comprehensive views on the processes that govern disease and resistance. Among others, the identification of secreted pathogen molecules (effectors) that modify immunity-associated processes has changed the plant–microbe interactions conceptual landscape. Effectors are now considered both important factors facilitating disease and novel probes, suited to study immunity in plants. In this review, we will describe the various mechanisms and processes that take place in the nucleus and help regulate immune responses in plants. Based on the premise that any process required for immunity could be targeted by pathogen effectors, we highlight and describe a number of functional assays that should help determine effector functions and their impact on immune-related processes. The identification of new effector functions that modify nuclear processes will help dissect nuclear signalling further and assist us in our bid to bolster immunity in crop plants
Shorelines Formed During Quaternary Marine Regression: Examples and Inferences from Southern Scotland (Progress Report)
researc
Sub-shot-noise shadow sensing with quantum correlations
The quantised nature of the electromagnetic field sets the classical limit to the sensitivity of position measurements. However, techniques based on the properties of quantum states can be exploited to accurately measure the relative displacement of a physical object beyond this classical limit. In this work, we use a simple scheme based on the split-detection of quantum correlations to measure the position of a shadow at the single-photon light level, with a precision that exceeds the shot-noise limit. This result is obtained by analysing the correlated signals of bi-photon pairs, created in parametric downconversion and detected by an electron multiplying CCD (EMCCD) camera employed as a split-detector. By comparing the measured statistics of spatially anticorrelated and uncorrelated photons we were able to observe a significant noise reduction corresponding to an improvement in position sensitivity of up to 17% (0.8dB). Our straightforward approach to sub-shot-noise position measurement is compatible with conventional shadow-sensing techniques based on the split-detection of light-fields, and yields an improvement that scales favourably with the detector’s quantum efficiency
Pregeometric Concepts on Graphs and Cellular Networks as Possible Models of Space-Time at the Planck-Scale
Starting from the working hypothesis that both physics and the corresponding
mathematics have to be described by means of discrete concepts on the
Planck-scale, one of the many problems one has to face is to find the discrete
protoforms of the building blocks of continuum physics and mathematics. In the
following we embark on developing such concepts for irregular structures like
(large) graphs or networks which are intended to emulate (some of) the generic
properties of the presumed combinatorial substratum from which continuum
physics is assumed to emerge as a coarse grained and secondary model theory. We
briefly indicate how various concepts of discrete (functional) analysis and
geometry can be naturally constructed within this framework, leaving a larger
portion of the paper to the systematic developement of dimensional concepts and
their properties, which may have a possible bearing on various branches of
modern physics beyond quantum gravity.Comment: 16 pages, Invited paper to appear in the special issue of the Journal
of Chaos, Solitons and Fractals on: "Superstrings, M, F, S ... Theory" (M.S.
El Naschie, C. Castro, Editors
Exploring Communication Tendencies of Program Facilitators
Audience analysis is a critical skill to forge relationships and develop effective communications. Programs provided by the Cooperative Extension Service must be aware of external and internal audiences to provide relevant information and evoke impacts. Berlo’s (1960) Source-Message-Channel-Receiver Model of Communications guided this formative evaluation of Extension staff, and horse 4-H club volunteer leaders (program facilitators) to expose internal communication tendencies in Arkansas. Findings identified that program facilitators seek horse-related information from a variety of sources, most frequently relying on personal connections and least frequently seeking Extension sources. Program facilitators share a variety of messages and most frequently relay information about deadlines to club members. Messages about recruitment and fundraising were shared least often. Program facilitators described utilizing a variety of personal and electronic channels to share messages with the greatest frequency for in-person communications. Incoming channels were less diverse than outgoing channels and primarily featured email, which program facilitators preferred. Program facilitators are primarily female, aged in their thirties, described lifetime involvement with 4-H and the horse industry, and most frequently reported having less than five years’ experience in their current position. The ground-level perspective of facilitators’ demographics and communication tendencies was evident in results of this study. In application, practitioners must continue to actively seek relationships with audiences, remain cognizant of communication factors, and provide accurate messaging through preferred channels
A comparative study of the education of young West Indian children in the United Kingdom : with particular reference to those from Jamaica
The main purpose of this thesis is to examine the way in which children of West Indian parentage and in particular those from Jamaica have settled into Primary schools in the United Kingdom since the 1960's. Two contrasting areas in the United Kingdom - the I.L.E.A. and Suffolk are reviewed in order to highlight their respective provisions with regard to Multi-Ethnic education.
The thesis commences with a short survey of the background and movement of Jamaican parents to the United Kingdom. A comparison is made between migration from Jamaica and that from other West Indian territories, and the process of integration with regard to employment, housing and education into the United Kingdom is briefly described.
The aspirations and frustrations of West Indian communities with regard to the education available to their children are described together with reactions of both indigenous British and West Indian adults toward education in English schools in which a large proportion of the children are from ethnic minorities.
In order to highlight the possible problems faced by both black and white communities in U.K. schools the model of "an ideal typical English Primary school" is established with regard to such aspects as administration, appointment of staff, organisation and curriculum, and methods of training teachers. The question is then asked - how successful is the typical English Primary School with regard to the needs and requirements of pupils from ethnic minority groups? Following this, changes in perception in Multi-cultural education during the 1970s and 1980s are discussed with particular regard to the multi-cultural policies and practices of the I.L.E.A. and Suffolk County Council Education Authority.
Local Education Authority Racial Policies and Practices in the U.K. during the 1980s are briefly surveyed and the thesis includes observations in five Primary Schools in the I.L.E.A. and in Ipswich, Suffolk in order to assess whether the multi-cultural policies of these two Authorities have been implemented in these particular schools and how.
The thesis concludes by discussing the applicability of multi cultural policies in the U.K. with the intention of assessing whether the policy of "Education for All" is an attainable or realistic goal with regard to the diversities of practices in British Primary Schools. This is discussed with particular reference to the higher valuations of Plowden, Swann and Anti-Racism as compared with those of the Ideal Typical Model
Adaptive foveated single-pixel imaging with dynamic super-sampling
As an alternative to conventional multi-pixel cameras, single-pixel cameras
enable images to be recorded using a single detector that measures the
correlations between the scene and a set of patterns. However, to fully sample
a scene in this way requires at least the same number of correlation
measurements as there are pixels in the reconstructed image. Therefore
single-pixel imaging systems typically exhibit low frame-rates. To mitigate
this, a range of compressive sensing techniques have been developed which rely
on a priori knowledge of the scene to reconstruct images from an under-sampled
set of measurements. In this work we take a different approach and adopt a
strategy inspired by the foveated vision systems found in the animal kingdom -
a framework that exploits the spatio-temporal redundancy present in many
dynamic scenes. In our single-pixel imaging system a high-resolution foveal
region follows motion within the scene, but unlike a simple zoom, every frame
delivers new spatial information from across the entire field-of-view. Using
this approach we demonstrate a four-fold reduction in the time taken to record
the detail of rapidly evolving features, whilst simultaneously accumulating
detail of more slowly evolving regions over several consecutive frames. This
tiered super-sampling technique enables the reconstruction of video streams in
which both the resolution and the effective exposure-time spatially vary and
adapt dynamically in response to the evolution of the scene. The methods
described here can complement existing compressive sensing approaches and may
be applied to enhance a variety of computational imagers that rely on
sequential correlation measurements.Comment: 13 pages, 5 figure
- …