Modified Dark Matter: Relating Dark Energy, Dark Matter and Baryonic Matter

Modified dark matter (MDM) is a phenomenological model of dark matter, inspired by gravitational thermodynamics. For an accelerating Universe with positive cosmological constant ($\Lambda$), such phenomenological considerations lead to the emergence of a critical acceleration parameter related to $\Lambda$. Such a critical acceleration is an effective phenomenological manifestation of MDM, and it is found in correlations between dark matter and baryonic matter in galaxy rotation curves. The resulting MDM mass profiles, which are sensitive to $\Lambda$, are consistent with observational data at both the galactic and cluster scales. In particular, the same critical acceleration appears both in the galactic and cluster data fits based on MDM. Furthermore, using some robust qualitative arguments, MDM appears to work well on cosmological scales, even though quantitative studies are still lacking. Finally, we comment on certain non-local aspects of the quanta of modified dark matter, which may lead to novel non-particle phenomenology and which may explain why, so far, dark matter detection experiments have failed to detect dark matter particles

Retardation of cochlear maturation and impaired hair cell function caused by deletion of all known thyroid hormone receptors

The deafness caused by early onset hypothyroidism indicates that thyroid hormone is essential for the development of hearing. We investigated the underlying roles of the TRa1 and TRß thyroid hormone receptors in the auditory system using receptor-deficient mice. TRa1 and TRß, which act as hormone-activated transcription factors, are encoded by the Thra and Thrb genes, respectively, and both are expressed in the developing cochlea. TRß is required for hearing because TRß-deficient (Thrb tm1/tm1) mice have a defective auditory-evoked brainstem response and retarded expression of a potassium current (I K,f) in the cochlear inner hair cells. Here, we show that although TRa1 is individually dispensable, TRa1 and TRß synergistically control an extended array of functions in postnatal cochlear development. Compared with Thrb tm1/tm1 mice, the deletion of all TRs inThra tm1/tm1 Thrb tm1/tm1mice produces exacerbated and novel phenotypes, including delayed differentiation of the sensory epithelium, malformation of the tectorial membrane, impairment of electromechanical transduction in outer hair cells, and a low endocochlear potential. The induction ofI K,f in inner hair cells was not markedly more retarded than in Thrb tm1/tm1mice, suggesting that this feature of hair cell maturation is primarily TRß-dependent. These results indicate that distinct pathways mediated by TRß alone or by TRß and TRa1 together facilitate control over an extended range of functions during the maturation of the cochlea

Alternative Lipid Sources in Aquafeeds

The global aquaculture industry is one of the fastest growing food production sectors with farmed seafood currently accounting for about 50% of all fish consumed in the world. It is estimated that aquaculture produces about 65 million tonnes of seafood valued at more than US$78 billion annually. Aquaculture is anticipated to play an increasingly important role in meeting the seafood demand of a growing human population. The rapid increase in aquaculture production worldwide has been fueled by the use of industrially manufactured aquafeeds. Conventionally, marine fish meal and fish oil are used as the major feed ingredients in the formulation of commercial aquafeeds to supply dietary protein and lipid, respectively. It is estimated that aquafeeds currently consume about 90% of the global supply of fish oil and many have predicted that the demand for fish oil from the aquaculture industry will imminently out strip supply. Marine fish oil production has not increased beyond 1.5 million tonnes for the past quarter of a century and in order to further expand, the global aquaculture industry cannot continue to rely solely on this source of lipid. The high demand, impending short supply and often times high prices makes dietary fish oil a bottle-neck in the farming of aquatic animals, and there is currently great urgency within the global aquafeed industry in finding suitable alternatives to replace marine fish oils. This article will give an overview of the various alternative lipid sources, grouped according to their main chemical characteristics. Their unique potential advantages and challenges for use in aquafeeds will be highlighted. The physiological effects of various lipid sources and their components on growth, lipid metabolism, health and post-harvest qualities of the farmed fish are briefly discussed

Mammography screening in general practice - a pilot study

Objectives: To evaluate the acceptability, feasibility and performance of a mammography screening programme for female patients in general practice. Design: A cross sectional study. Setting: A general practice clinic and a resiona/ hospital in Hong Kong. Subjects: 500 Chinese women aged 45 years or older attending a university teaching general practice clinic on Hong Kong Island. Main outcome measures: The rates of uptake of screening, retakes, recall for further evaluation and fine needle aspiration (FNA), and participants' opinion on mammography. Results: The uptake rate of screening was 37%. Mammography was feasible for all participants, 12% had additional films and 7% required retakes. Sixteen percent were recalled for further evaluation, 4% had FNA, one had an excisional biopsy which revealed no cancer. Most women rated pain of mammography mild to moderate and did not find it embarrassing, 98% said that they would recommend it to their friends and 87% indicated that they would do it again. Conclusions: Mammography screening for Chinese women presenting to general practice was technically feasible. Most women found the experience of mammography screening acceptable. The uptake rate of mammography screening was much lower than what would be required to benefit the overall breast cancer mortality. There was also room for improvement in our retake and recall rates. We need to weigh the possible benefit of mammography screening against the stress and resources associated with additional films, retakes, recalls for further evaluation, FNA and excisional biopsy in individuals with false positive results.published_or_final_versio

End-user perspectives on the Adoption of Wireless Applications: Price of Convenience and a Model for Contextual Analysis

Information services delivered via wireless, portable communication devices continue to pervade our work and leisure spaces. While people are continuously bombarded with promises of newer and better ways to maintain contact with others and to have constant access to information, however, there remain a number of open issues that inhibit the potential for an open information society. The bidirectional influence between such wireless technologies and applications and their potential end-users, contributes to the development of both the technologies and applications and the social setting in which they are embedded. In this paper, we extend current studies of Information and Communications Technology (ICT) uptake by integrating interpretations of “ubiquitous computing” and its pervasion of everyday life. We draw upon findings from a range of IS research to structure our future studies of adoption issues in relation to a variety of wireless application cases. We show that, while some “traditional” IS/IT dimensions of uptake still hold, there are now a variety of other “non- utilitarian (hedonic)” factors that developers and designers need to take into account. We conclude by proposing a research model – expanded from model of user acceptability and product uptake, a descriptive framework based on the “Price of Convenience”(Ng-Kruelle, Swatman, Rebne and Hampe 2002)

Big Thunder Sports and Recreation Park: Business Case for Reopening of Big Thunder

In late November 2010, Professor Doug Thom, Faculty of Education at Lakehead University asked Dr. Bryan Poulin, Faculty of Business Administration at Lakehead University, if he would be interested in preparing a business case for the reopening of Big Thunder, known to many parts of the world for hosting the 1995 Nordic World Ski Championships. On 28 December, Bryan Poulin and finance student Doug Ng agreed to prepare a Business Case with the assistance of Friends of Big Thunder (FOBT). Interviews with 25 representative stakeholders in the Thunder Bay Region and across the country attest to the support and the enthusiasm that Big Thunder generates in the Thunder Bay Community and well beyond it. This may seem surprising since it has been 15 years since it was closed following the 1995 World Championships. Surveys returned by 56 stakeholders also confirm what Big Thunder needs to become, and what it does not. Big Thunder needs to become a year around sports, recreational and training center for people young to older, ordinary and special in all sports and recreation and other activities that naturally belong on Site. Big Thunder is not to be left to deteriorate, nor is it to be sold to the highest bidder. In short it is a public asset, and ought to be treated as such. Only 14 km from Thunder Bay, Big Thunder holds tremendous potential to add to the health and social and economic well-being of the City and Region of Thunder Bay, the Province of Ontario and beyond. This Business Case agrees with two previous studies – UMA Engineering Study (2005) commissioned by the Ontario Realty Corporation and Lakehead University School of Outdoor Recreation Study (2003) – in that it finds only three key challenges to reopening the Big Thunder Site: right to use the Site to its highest potential; sufficient funding to reopen the Site properly, and long term sustainability. Five options for reopening the Site are considered, from modest to visionary. It is the consensus of the stakeholders -- confirmed by preliminary market and financial feasibility—to choose the most complete option. The one time capital cost to refurbish and expand the Big Thunder Site to its potential is $22 million. This includes detailed design and contingency costs, and$2 million for supply of potable water to the Site by the City of Thunder Bay, and assumed as its contribution. The other $20 million in capital cost is to be provided by higher levels of Government. Others, for example Fort William First Nation, Lakehead University and Confederation College, would contribute though higher education and training programs. Private organizations contribute through partnerships, memberships and donations. Visitors pay reasonable usage fees. Big Thunder becomes sustainable by Year 5 with net income, or revenue minus costs, is sufficient to cover current operations and future maintenance and capital improvements. Big Thunder is worth many times$22 million it will cost to reopen. Benefits are many: not only the ‘destination attraction’ called for in the 2008 Rosehart Report and 150 new jobs; $4 million annually to the local economy; new opportunities for young to old, ordinary and special. One representative stated, “Our sport could really use another top level facility in North America.” Another, “Big Thunder is a magnificent natural resource that can support related economic development to the City and surrounding area. It is more than economic benefit. It is social and sport and recreation, and economic.” The vision is for Big Thunder to be an important part of the Region, and beyond. Implementation is in five steps: 1) securing right to use the Site for Sports, recreation and other activities; 2) seeking sufficient funding to open the Site properly; 3) assembling an ethical, experienced Board and senior management team; 4) incorporating Big Thunder Corporation as a not-for-profit enterprise; 5) pursuing partnerships in ways that provide optimal social, environmental and economic benefits to the Community of sports, recreation and related stakeholders. The following Concept Drawing is part of this summary

X-ray analysis of the proper motion and pulsar wind nebula for PSR J1741-2054

We obtained six observations of PSR J1741-2054 using the $Chandra$ ACIS-S detector totaling $\sim$300 ks. By registering this new epoch of observations to an archival observation taken 3.2 years earlier using X-ray point sources in the field of view, we have measured the pulsar proper motion at $\mu =109 \pm 10 {\rm mas\ yr}^{-1}$ in a direction consistent with the symmetry axis of the observed H$\alpha$ nebula. We investigated the inferred past trajectory of the pulsar but find no compelling association with OB associations in which the progenitor may have originated. We confirm previous measurements of the pulsar spectrum as an absorbed power law with photon index $\Gamma$=2.68$\pm$0.04, plus a blackbody with an emission radius of (4.5$^{+3.2}_{-2.5})d_{0.38}$ km, for a DM-estimated distance of $0.38d_{0.38}$ kpc and a temperature of $61.7\pm3.0$ eV. Emission from the compact nebula is well described by an absorbed power law model with a photon index of $\Gamma$ = 1.67$\pm$0.06, while the diffuse emission seen as a trail extending northeast of the pulsar shows no evidence of synchrotron cooling. We also applied image deconvolution techniques to search for small-scale structures in the immediate vicinity of the pulsar, but found no conclusive evidence for such structures.Comment: 7 pages, 8 figures, 4 Tables; Accepted by Ap