A bio-inspired image coder with temporal scalability

We present a novel bio-inspired and dynamic coding scheme for static images. Our coder aims at reproducing the main steps of the visual stimulus processing in the mammalian retina taking into account its time behavior. The main novelty of this work is to show how to exploit the time behavior of the retina cells to ensure, in a simple way, scalability and bit allocation. To do so, our main source of inspiration will be the biologically plausible retina model called Virtual Retina. Following a similar structure, our model has two stages. The first stage is an image transform which is performed by the outer layers in the retina. Here it is modelled by filtering the image with a bank of difference of Gaussians with time-delays. The second stage is a time-dependent analog-to-digital conversion which is performed by the inner layers in the retina. Thanks to its conception, our coder enables scalability and bit allocation across time. Also, our decoded images do not show annoying artefacts such as ringing and block effects. As a whole, this article shows how to capture the main properties of a biological system, here the retina, in order to design a new efficient coder.Comment: 12 pages; Advanced Concepts for Intelligent Vision Systems (ACIVS 2011

Negotiating the boundaries of parental school engagement: the role of social space and symbolic capital in urban teachers' perspectives

As public schools continue to be driven by standards-based accountability practices, scholars contend that family engagement must become more egalitarian, with parents contributing their own insights for the betterment of the entire school community. Classroom teachers are key stakeholders in this process, with enormous potential impact. Using Bourdieu’s concepts of social space and symbolic capital, we examined teachers’ perspectives on their role in engaging diverse parents, using focus group interviews with urban classroom teachers. Multi-layered qualitative analyses elicited three themes that illustrated the powerful, but contradictory, positioning of teachers in facilitating authentic partnerships with families: (a) creating responsive relationships (b) casting engagement as education, and (c) creating varied-and tailored-opportunities, yet also revealed teachers’ assertions of power and authority, most often expressed as a need for boundaries between home and school. A progressive approach to family engagement and educator resistance is discussed, whereby teachers engage in collaborative advocacy with urban families to reclaim the notion of teaching as a public service, aimed at the promotion of equitable, accessible, and culturally responsive schools.Accepted manuscrip

Distributed video coding for wireless video sensor networks: a review of the state-of-the-art architectures

Distributed video coding (DVC) is a relatively new video coding architecture originated from two fundamental theorems namely, Slepian–Wolf and Wyner–Ziv. Recent research developments have made DVC attractive for applications in the emerging domain of wireless video sensor networks (WVSNs). This paper reviews the state-of-the-art DVC architectures with a focus on understanding their opportunities and gaps in addressing the operational requirements and application needs of WVSNs

Agricultural trade publications and the 2012 Midwestern U.S. drought: a missed opportunity for climate risk communication

The Midwestern United States experienced a devastating drought in 2012, leading to reduced corn and soybean yields and increased instances of pests and disease. Climate change induced weather variability and extremes are expected to increase in the future, and have and will continue to impact the agricultural sector. This study investigated how agricultural trade publications portrayed the 2012 U.S. Midwestern drought, whether climate change was associated with drought, and whether these publications laid out transformative adaptation measures farmers could undertake in order to increase their adaptive capacity for future climate uncertainty. We performed a content analysis of 1000 media reports between April 1, 2012 and March 31, 2014, sampled from ten agricultural trade publications. The results lead us to suggest that trade publications’ 2012 U.S. Midwestern drought discussion lacked information that would allow farmers and agricultural advisors to assess climate change risk and subsequent potential adaptive management strategies. Agricultural risk from climate change is very real, and farmers will need to adapt. The agricultural trade publications studied missed an opportunity to convey risk from climate change and the transformative adaptation practices necessary for a sustainable and resilient agricultural system

A nonhuman primate model of inherited retinal disease.

Inherited retinal degenerations are a common cause of untreatable blindness worldwide, with retinitis pigmentosa and cone dystrophy affecting approximately 1 in 3500 and 1 in 10,000 individuals, respectively. A major limitation to the development of effective therapies is the lack of availability of animal models that fully replicate the human condition. Particularly for cone disorders, rodent, canine, and feline models with no true macula have substantive limitations. By contrast, the cone-rich macula of a nonhuman primate (NHP) closely mirrors that of the human retina. Consequently, well-defined NHP models of heritable retinal diseases, particularly cone disorders that are predictive of human conditions, are necessary to more efficiently advance new therapies for patients. We have identified 4 related NHPs at the California National Primate Research Center with visual impairment and findings from clinical ophthalmic examination, advanced retinal imaging, and electrophysiology consistent with achromatopsia. Genetic sequencing confirmed a homozygous R565Q missense mutation in the catalytic domain of PDE6C, a cone-specific phototransduction enzyme associated with achromatopsia in humans. Biochemical studies demonstrate that the mutant mRNA is translated into a stable protein that displays normal cellular localization but is unable to hydrolyze cyclic GMP (cGMP). This NHP model of a cone disorder will not only serve as a therapeutic testing ground for achromatopsia gene replacement, but also for optimization of gene editing in the macula and of cone cell replacement in general