Mathematical hybrid models for image segmentation.

Two hybrid image segmentation models that are able to process a wide variety of images are proposed. The models take advantage of global (region) and local (edge) data of the image to be segmented. The first one is a region-based PDE model that incorporates a combination of global and local statistics. The influence of each statistic is controlled using weights obtained via an asymptotically stable exponential function. Through incorporation of edge information, the second model extends the capabilities of a strictly region-based variational formulation, making it able to process more general images. Several examples are provided showing the improvements of the proposed models over recent methods along with an application to dermoscopy imaging. A number of avenues for future research are also discussed

The impact of HIV stigma in accessing sexual health services among black sub-Sahara African woman and gay men: a systematic literature review

For many years HIV related stigma and denial has characterized the pandemic and presented a major challenge to the uptake of HIV testing, prevention and normalization among black sub-Sahara African (BSSA) women and gay men. The challenges have had a ripple effect on the access to sexual health services and resources within the communities in question. This article reviews literature on the types of HIV stigma and its impact in accessing sexual health services and resources by the aforesaid communities. Furthermore the article will review literature on attempts made to de-mystify HIV stigma in order to increase its uptake among the groups in question. The findings from the literature suggest that HIV stigma remains a big challenge to the uptake of HIV testing and access to sexual health services including resources among different social groups under consideration in this article. Despite the efforts to normalize HIV testing, including access to sexual health services and resources, HIV stigma has tended to take a new complex dimension and has proved hard to disappear. In addition to the current efforts to end HIV stigma there is need to understand more about the forms, contexts and social construction of HIV stigma and sexual health seeking behavior in different communities, if we are to succeed in our endeavor to control the epidemic

Correlations between reflected and transmitted intensity patterns emerging from opaque disordered media

The propagation of monochromatic light through a scattering medium produces speckle patterns in reflection and transmission, and the apparent randomness of these patterns prevents direct imaging through thick turbid media. Yet, since elastic multiple scattering is fundamentally a linear and deterministic process, information is not lost but distributed among many degrees of freedom that can be resolved and manipulated. Here we demonstrate experimentally that the reflected and transmitted speckle patterns are correlated, even for opaque media with thickness much larger than the transport mean free path, proving that information survives the multiple scattering process and can be recovered. The existence of mutual information between the two sides of a scattering medium opens up new possibilities for the control of transmitted light without any feedback from the target side, but using only information gathered from the reflected speckle.Comment: 6 pages, 4 figure

Blind Ghost Imaging

Ghost imaging is an unconventional optical imaging technique that reconstructs the shape of an object combining the measurement of two signals: one that interacted with the object, but without any spatial information, the other containing spatial information, but that never interacted with the object. Ghost imaging is a very flexible technique, that has been generalized to the single-photon regime, to the time domain, to infrared and terahertz frequencies, and many more conditions. Here we demonstrate that ghost imaging can be performed without ever knowing the patterns illuminating the object, but using patterns correlated with them, doesn't matter how weakly. As an experimental proof we exploit the recently discovered correlation between the reflected and transmitted light from a scattering layer, and reconstruct the image of an object hidden behind a scattering layer using only the reflected light, which never interacts with the object. This method opens new perspectives for non-invasive imaging behind or within turbid media.Comment: 5 pages, 4 figure

Unravelling Diatoms’ Potential for the Bioremediation of Oil Hydrocarbons in Marine Environments

The search for practical solutions to alleviate the destructive impact of petroleum hydrocarbons in marine environments is contributing to the implementation of prospecting strategiesfor indigenous microorganisms with biodegradative and bioremediation potential. The levels ofpetroleum contamination entering the marine environment each year have been estimated at around1.3 million tonnes, a figure that is expected to increase by 1.9% annually over the next decade. Therecent interest in decarbonizing our energy system and accelerating the clean energy transitionhas created a demand for greener technologies and strategies to find innovative, sustainable, andcost-effective treatments for the marine environment. Diatoms (Bacillariophyta) are one of the mostdiverse and successful taxa in coastal–marine environments and are a relatively untapped pool ofbiodiversity for biotechnological applications. Recent reports have revealed the significant presenceof diatoms associated with oil spills and petroleum hydrocarbon degradation. Most diatoms cansecrete substantial amounts of exopolysaccharides (EPSs) into their environment, which can act asbiosurfactants that, in addition to oxygen and other enzymes produced by diatoms, create suitableconditions to enhance hydrocarbon solubility and degradation into less toxic compounds in seawater. Recent reports on the biodegradation of aliphatic and aromatic hydrocarbons by diatoms areindicative of the potential of these taxa to achieve success in the bioremediation of hydrocarbons inmarine environments. This review highlights the main attributes and roles that diatoms could play inintegrated strategies for biodegradation and bioremediation of petroleum hydrocarbon pollutantsand as such represent a green, eco-friendly, and sustainable contribution to mitigate damage tobiodiversity and value chains of marine ecosystems

Considering sustainability in project management decision making; an investigation using Q-methodology

Abstract: Sustainability is one of the most important challenges of our time. Projects play a pivotal role in the realization of more sustainable business practices and the concept of sustainability has also been linked to project management. However, how managers of projects consider sustainability in their operational daily work is still to be explored. This paper uses Q-methodology to investigate the consideration of sustainability aspects in the decision making processes of project managers. The research question was How are dimensions of sustainability considered in the decision-making processes of project managers in relation to the triple constraint of time, cost and quality? Based on the Q-sort of selected respondents, the study found that the consideration of sustainability principles is underrepresented, compared to the triple constraint criteria. However, the analysis of the individual Q-sorts revealed four distinct perspectives that differ significantly in their consideration of sustainability principles and triple constraint criteria

Workplace environmental conditions and life satisfaction in Spain

This paper expands the research on subjective well-being and outdoor environmental conditions by considering environmental conditions indoors. Specifically, we examine the impact on life satisfaction of self-perceived levels of air and noise pollution in the workplace. We provide a monetary valuation of these environmental conditions, using the life-satisfaction approach. Our results demonstrate that poor air quality and high noise levels in the workplace markedly diminish life satisfaction. This holds even after we control for potential endogeneity arising from simultaneity of self-perceived workplace environmental variables and life satisfaction, by employing an instrumental variable strategy