PADS: Privacy-preserving Auction Design forAllocating Dynamically Priced Cloud Resources

With the rapid growth of Cloud Computing technologies, enterprises are increasingly deploying their services in the Cloud. Dynamically priced cloud resources such as the Amazon EC2 Spot Instance provides an efficient mechanism for cloud service providers to trade resources with potential buyers using an auction mechanism. With the dynamically priced cloud resource markets, cloud consumers can buy resources at a significantly lower cost than statically priced cloud resources such as the on-demand instances in Amazon EC2. While dynamically priced cloud resources enable to maximize datacenter resource utilization and minimize cost for the consumers, unfortunately, such auction mechanisms achieve these benefits only at a cost significant of private information leakage. In an auction-based mechanism, the private information includes information on the demands of the consumers that can lead an attacker to understand the current computing requirements of the consumers and perhaps even allow the inference of the workload patterns of the consumers. In this paper, we propose PADS, a strategy-proof differentially private auction mechanism that allows cloud providers to privately trade resources with cloud consumers in such a way that individual bidding information of the cloud consumers is not exposed by the auction mechanism. We demonstrate that PADS achieves differential privacy and approximate truthfulness guarantees while maintaining good performance in terms of revenue gains and allocation efficiency. We evaluate PADS through extensive simulation experiments that demonstrate that in comparison to traditional auction mechanisms, PADS achieves relatively high revenues for cloud providers while guaranteeing the privacy of the participating consumers

Motion Deblurring in the Wild

The task of image deblurring is a very ill-posed problem as both the image and the blur are unknown. Moreover, when pictures are taken in the wild, this task becomes even more challenging due to the blur varying spatially and the occlusions between the object. Due to the complexity of the general image model we propose a novel convolutional network architecture which directly generates the sharp image.This network is built in three stages, and exploits the benefits of pyramid schemes often used in blind deconvolution. One of the main difficulties in training such a network is to design a suitable dataset. While useful data can be obtained by synthetically blurring a collection of images, more realistic data must be collected in the wild. To obtain such data we use a high frame rate video camera and keep one frame as the sharp image and frame average as the corresponding blurred image. We show that this realistic dataset is key in achieving state-of-the-art performance and dealing with occlusions

Skin-derived dendritic cells acquire and degrade the scrapie agent following in vitro exposure

The accumulation of the scrapie agent in lymphoid tissues following inoculation via the skin is critical for efficient neuroinvasion, but how the agent is initially transported from the skin to the draining lymph node is not known. Langerhans cells (LCs) are specialized antigen-presenting cells that continually sample their microenvironment within the epidermis and transport captured antigens to draining lymph nodes. We considered LCs probable candidates to acquire and transport the scrapie agent after inoculation via the skin. XS106 cells are dendritic cells (DCs) isolated from mouse epidermis with characteristics of mature LC cells. To investigate the potential interaction of LCs with the scrapie agent XS106 cells were exposed to the scrapie agent in vitro. We show that XS106 cells rapidly acquire the scrapie agent following in vitro exposure. In addition, XS106 cells partially degrade the scrapie agent following extended cultivation. These data suggest that LCs might acquire and degrade the scrapie agent after inoculation via the skin, but data from additional experiments demonstrate that this ability could be lost in the presence of lipopolysaccharide or other immunostimulatory molecules. Our studies also imply that LCs would not undergo maturation following uptake of the scrapie agent in the skin, as the expression of surface antigens associated with LC maturation were unaltered following exposure. In conclusion, although LCs or DCs have the potential to acquire the scrapie agent within the epidermis our data suggest it is unlikely that they become activated and stimulated to transport the agent to the draining lymph node

Effects of aortic root motion on wall stress in the Marfan aorta before and after personalised aortic root support (PEARS) surgery

Aortic root motion was previously identified as a risk factor for aortic dissection due to increased longitudinal stresses in the ascending aorta. The aim of this study was to investigate the effects of aortic root motion on wall stress and strain in the ascending aorta and evaluate changes before and after implantation of personalised external aortic root support (PEARS). Finite element (FE) models of the aortic root and thoracic aorta were developed using patient-specific geometries reconstructed from pre- and post-PEARS cardiovascular magnetic resonance (CMR) images in three Marfan patients. The wall and PEARS materials were assumed to be isotropic, incompressible and linearly elastic. A static load on the inner wall corresponding to the patients' pulse pressure was applied. Cardiovascular MR cine images were used to quantify aortic root motion, which was imposed at the aortic root boundary of the FE model, with zero-displacement constraints at the distal ends of the aortic branches and descending aorta. Measurements of the systolic downward motion of the aortic root revealed a significant reduction in the axial displacement in all three patients post-PEARS compared with its pre-PEARS counterparts. Higher longitudinal stresses were observed in the ascending aorta when compared with models without the root motion. Implantation of PEARS reduced the longitudinal stresses in the ascending aorta by up to 52%. In contrast, the circumferential stresses at the interface between the supported and unsupported aorta were increase by up to 82%. However, all peak stresses were less than half the known yield stress for the dilated thoracic aorta

Insights into iguanodontian dental architecture from an Early Cretaceous Chinese basal hadrosauriform maxilla (Ornithischia: Iguanodontia)

Basal hadrosauriform iguanodontian dinosaurs have been invaluable towards understanding the evolution of the complex and highly efficient advanced hadrosauriform tooth battery dental system. Here we report a new basal hadrosauriform maxilla specimen - IVPP V22529 - from the Dashuiguo Formation of Maortu, Nei Mongol, China that preserves a corrugated middle ventrolateral margin that differs from the straight and undulating ventral margins found in most iguandontian and non-iguanodontian dinosaurs. The uniqueness of this ventrolateral margin relates to a new dental structure - cementum ‘jackets’ that wrap about the labial sides of the teeth. To our knowledge this is the first time that cementum has been described migrated onto the tooth crowns of iguandontians (and other dinosaurs), but this trait is common amongst mammals. This dental morphology - seen in a similar form in the basal hadrosauriform Equijubus – therefore broadens our knowledge of iguanodontian maxillary anatomy and shows that the basal hadrosauriform dental system was more morphologically complex than previously thought. IVPP V22529 resembles maxillae specimens of Probactrosaurus gobiensis, a contemporaneous taxon known from the same locality in North China, in sharing an inferred subtriangular shape, a relatively flat lateral surface bearing a low row of foramina as well as similar-looking teeth. However, the presence of a unique corrugated middle ventrolateral margin in IVPP V22529, a low row of foramina on its lateral surface that also open anteriorly and increase in size posteriorly as well as a prominent medial shelf suggests that this specimen does not belong to P. gobiensis. However, these differences could conceivably be related to ontogenetic and sexual variation, which have not been fully documented in P. gobiensis. More detailed comparisons of IVPP V22529 and Probactrosaurus are also hampered by the missing posterior portion of IVPP V22529 as well as the missing anterior ramii in Probactrosaurus maxillae specimens. It is clear though that IVPP V22529 is different from the more advanced Northern Chinese hadrosauriforms Bactrosaurus and Gilmoreosaurus. The latter lack well-developed maxillary grooves on their medial shelves, unlike IVPP V22529, but all three taxa possess less-developed ones on the medial surfaces of the anteromedial processes of the anterior ramii. Different to IVPP V22529, Gilmoreosaurus also has foramina that are more highly-positioned on the lateral surface of its maxilla as well as a row of larger and more circular ‘special’ foramina on its medial surface. Thus, at this time, IVPP V22529 is identified as a basal hadrosauriform and not as a new genus or as a new species of Probactrosaurus.published_or_final_versio

Mechanistic Modeling of Microtopographic Impacts on CO2 and CH4 Fluxes in an Alaskan Tundra Ecosystem Using the CLM-Microbe Model

Spatial heterogeneities in soil hydrology have been confirmed as a key control on CO2 and CH4 fluxes in the Arctic tundra ecosystem. In this study, we applied a mechanistic ecosystem model, CLM-Microbe, to examine the microtopographic impacts on CO2 and CH4 fluxes across seven landscape types in Utqiaġvik, Alaska: trough, low-centered polygon (LCP) center, LCP transition, LCP rim, high-centered polygon (HCP) center, HCP transition, and HCP rim. We first validated the CLM-Microbe model against static-chamber measured CO2 and CH4 fluxes in 2013 for three landscape types: trough, LCP center, and LCP rim. Model application showed that low-elevation and thus wetter landscape types (i.e., trough, transitions, and LCP center) had larger CH4 emissions rates with greater seasonal variations than high-elevation and drier landscape types (rims and HCP center). Sensitivity analysis indicated that substrate availability for methanogenesis (acetate, CO2 + H2) is the most important factor determining CH4 emission, and vegetation physiological properties largely affect the net ecosystem carbon exchange and ecosystem respiration in Arctic tundra ecosystems. Modeled CH4 emissions for different microtopographic features were upscaled to the eddy covariance (EC) domain with an area-weighted approach before validation against EC-measured CH4 fluxes. The model underestimated the EC-measured CH4 flux by 20% and 25% at daily and hourly time steps, suggesting the importance of the time step in reporting CH4 flux. The strong microtopographic impacts on CO2 and CH4 fluxes call for a model-data integration framework for better understanding and predicting carbon flux in the highly heterogeneous Arctic landscape

Transient receptor potential canonical 5 channels plays an essential role in hepatic dyslipidemia associated with cholestasis.

Transient receptor potential canonical 5 (TRPC5), a calcium-permeable, non-selective cation channel is expressed in the periphery, but there is limited knowledge of its regulatory roles in vivo. Endogenous modulators of TRPC5 include a range of phospholipids that have an established role in liver disease, including lysophosphatidylcholine (LPC). Cholestasis is characterized by impairment of excretion of bile acids, leading to elevation of hepatic bile acids. We investigated the contribution of TRPC5 in a murine model of cholestasis. Wild-type (WT) and TRPC5 knock-out (KO) mice were fed a diet supplemented with 0.5% cholic acid (CA) for 21 days. CA-diet supplementation resulted in enlargement of the liver in WT mice, which was ameliorated in TRPC5 KO mice. Hepatic bile acid and lipid content was elevated in WT mice, with a reduction observed in TRPC5 KO mice. Consistently, liver enzymes were significantly increased in cholestatic WT mice and significantly blunted in TRPC5 KO mice. Localized dyslipidaemia, secondary to cholestasis, was investigated utilizing a selected lipid analysis. This revealed significant perturbations in the lipid profile following CA-diet feeding, with increased cholesterol, triglycerides and phospholipids, in WT, but not TRPC5 KO mice. Our results suggest that activation of TRPC5 contributes to the development of cholestasis and associated dyslipidemia. Modulation of TRPC5 activity may present as a novel therapeutic target for liver disease

Towards Accurate Estimation of the Proportion of True Null Hypotheses in Multiple Testing

BACKGROUND: Biomedical researchers are now often faced with situations where it is necessary to test a large number of hypotheses simultaneously, eg, in comparative gene expression studies using high-throughput microarray technology. To properly control false positive errors the FDR (false discovery rate) approach has become widely used in multiple testing. The accurate estimation of FDR requires the proportion of true null hypotheses being accurately estimated. To date many methods for estimating this quantity have been proposed. Typically when a new method is introduced, some simulations are carried out to show the improved accuracy of the new method. However, the simulations are often very limited to covering only a few points in the parameter space. RESULTS: Here I have carried out extensive in silico experiments to compare some commonly used methods for estimating the proportion of true null hypotheses. The coverage of these simulations is unprecedented thorough over the parameter space compared to typical simulation studies in the literature. Thus this work enables us to draw conclusions globally as to the performance of these different methods. It was found that a very simple method gives the most accurate estimation in a dominantly large area of the parameter space. Given its simplicity and its overall superior accuracy I recommend its use as the first choice for estimating the proportion of true null hypotheses in multiple testing