On Achievable Rates of the Two-user Symmetric Gaussian Interference Channel

We study the Han-Kobayashi (HK) achievable sum rate for the two-user symmetric Gaussian interference channel. We find the optimal power split ratio between the common and private messages (assuming no time-sharing), and derive a closed form expression for the corresponding sum rate. This provides a finer understanding of the achievable HK sum rate, and allows for precise comparisons between this sum rate and that of orthogonal signaling. One surprising finding is that despite the fact that the channel is symmetric, allowing for asymmetric power split ratio at both users (i.e., asymmetric rates) can improve the sum rate significantly. Considering the high SNR regime, we specify the interference channel value above which the sum rate achieved using asymmetric power splitting outperforms the symmetric case.Comment: 7 pages, to appear in Allerton 201

Chapter 9 Gene Drive Strategies for Population Replacement

Gene drive systems are selfish genetic elements capable of spreading into a population despite a fitness cost. A variety of these systems have been proposed for spreading disease-refractory genes into mosquito populations, thus reducing their ability to transmit diseases such as malaria and dengue fever to humans. Some have also been proposed for suppressing mosquito populations. We assess the alignment of these systems with design criteria for their safety and efficacy. Systems such as homing endonuclease genes, which manipulate inheritance through DNA cleavage and repair, are highly invasive and well-suited to population suppression efforts. Systems such as Medea, which use combinations of toxins and antidotes to favor their own inheritance, are highly stable and suitable for replacing mosquito populations with disease-refractory varieties. These systems offer much promise for future vector-borne disease control

Locked nucleic acid oligomers as handles for single molecule manipulation.

Single-molecule manipulation (SMM) techniques use applied force, and measured elastic response, to reveal microscopic physical parameters of individual biomolecules and details of biomolecular interactions. A major hurdle in the application of these techniques is the labeling method needed to immobilize biomolecules on solid supports. A simple, minimally-perturbative labeling strategy would significantly broaden the possible applications of SMM experiments, perhaps even allowing the study of native biomolecular structures. To accomplish this, we investigate the use of functionalized locked nucleic acid (LNA) oligomers as biomolecular handles that permit sequence-specific binding and immobilization of DNA. We find these probes form bonds with DNA with high specificity but with varied stability in response to the direction of applied mechanical force: when loaded in a shear orientation, the bound LNA oligomers were measured to be two orders of magnitude more stable than when loaded in a peeling, or unzipping, orientation. Our results show that LNA provides a simple, stable means to functionalize dsDNA for manipulation. We provide design rules that will facilitate their use in future experiments

Snake eels (Ophichthidae) of the remote St. Peter and St. Paul’s Archipelago (Equatorial Atlantic) : Museum records after 37 years of shelf life

Despite of its major zoogeographical interest, the biological diversity of central Atlantic oceanic islands are still poorly known because of its remoteness. Incomplete species inventories are a hindrance to macroecology and conservation because knowledge on species distribution are important for identifying patterns and processes in biodiversity and for conservation planning. Records of the snake-eel family Ophichthidae for the St. Peter and St. Paul’s Archipelago, Brazil, are presented for the first time after revision of material collected and deposited in a museum collection 37 yrs ago. Specimens of Apterichtus kendalli and Herpetoichthys regius were collected using rotenone on sand bottoms and one Myrichthys sp. was observed and photographed swimming over a rocky reef. Remarkably, these species were not seen or collected in the St. Peter and St. Paul’s Archipelago ever since despite the substantial increase of biological expeditions over the past two decades, suggesting that the unjustified rotenone sampling prohibition in Brazil is hindering advancement of the nation’s biological diversity knowledge.info:eu-repo/semantics/publishedVersio

Effects of Light Attenuation on Local and Bulk Mechanical Properties of Photopolymerized PEG Hydrogels

Cell experiments investigating cell behavior as a function of material stiffness are often carried out on the surface of hydrogels. An assumption that the bulk hydrogel mechanical properties represent the surface properties is often employed but in many cases is not valid. In photo-initiated radical polymerization, photons are absorbed by initiator chromophores generating high energy electrons. As photons progress through the prepolymer solution, the intensity of light that reaches the distal end of the solution is decreased through this attenuation. This work aims to determine whether light attenuation plays a significant role in local stiffness within a poly(ethylene glycol) diacrylate (PEGDA) hydrogel, compared to its bulk stiffness. Differences in bulk properties were tested by varying the polymerization parameters of hydrogel cylindrical plugs, including sample thickness (0.7mm – 1.2mm), photoinitiator type (EosinY vs LAP), PEGDA weight percent, and exposure time. Mechanical loading data of the plugs was analyzed to reveal the relationships between the physical properties (e.g. thickness, surface area, volume) and chemical properties (e.g. monomer and initiator concentrations, exposure settings). Preliminary data suggests that an appreciable difference in physical properties exists between gels of differing thickness (1.0mm vs 0.3mm based on gel point). The goals of this work are to quantify the extent of this difference based on sample thickness, and to compare the bulk stiffness data with local surface stiffness measurements obtained using an AFM nano-indentation technique and determine whether changes in bulk properties carry over to changes in surface properties

Toward a framework for data quality in cloud-based health information system

This Cloud computing is a promising platform for health information systems in order to reduce costs and improve accessibility. Cloud computing represents a shift away from computing being purchased as a product to be a service delivered over the Internet to customers. Cloud computing paradigm is becoming one of the popular IT infrastructures for facilitating Electronic Health Record (EHR) integration and sharing. EHR is defined as a repository of patient data in digital form. This record is stored and exchanged securely and accessible by different levels of authorized users. Its key purpose is to support the continuity of care, and allow the exchange and integration of medical information for a patient. However, this would not be achieved without ensuring the quality of data populated in the healthcare clouds as the data quality can have a great impact on the overall effectiveness of any system. The assurance of the quality of data used in healthcare systems is a pressing need to help the continuity and quality of care. Identification of data quality dimensions in healthcare clouds is a challenging issue as data quality of cloud-based health information systems arise some issues such as the appropriateness of use, and provenance. Some research proposed frameworks of the data quality dimensions without taking into consideration the nature of cloud-based healthcare systems. In this paper, we proposed an initial framework that fits the data quality attributes. This framework reflects the main elements of the cloud-based healthcare systems and the functionality of EHR

Lattice Modeling of Early-Age Behavior of Structural Concrete.

The susceptibility of structural concrete to early-age cracking depends on material composition, methods of processing, structural boundary conditions, and a variety of environmental factors. Computational modeling offers a means for identifying primary factors and strategies for reducing cracking potential. Herein, lattice models are shown to be adept at simulating the thermal-hygral-mechanical phenomena that influence early-age cracking. In particular, this paper presents a lattice-based approach that utilizes a model of cementitious materials hydration to control the development of concrete properties, including stiffness, strength, and creep resistance. The approach is validated and used to simulate early-age cracking in concrete bridge decks. Structural configuration plays a key role in determining the magnitude and distribution of stresses caused by volume instabilities of the concrete material. Under restrained conditions, both thermal and hygral effects are found to be primary contributors to cracking potential

Memories of the future

The year is 2020. Sheffield University’s MSc in Electronic & Digital Library Management has been running for 10 years. What paths have its graduates’ careers taken

The influence of lesion characteristics on application time of an infiltrate applied to MIH lesions on anterior teeth:An exploratory in vivo pilot study

Objectives: To evaluate the factors that influences the kinetics of resin infiltration of molar incisor hypomineralisation (MIH) lesions on permanent anterior teeth. Methods: Demarcated MIH lesions with homogeneous and heterogeneous lesion body appearance, Types 1 (n = 14) and 2 (n = 18), respectively, were selected. After removal of the lesion surface layer using a tapered diamond finishing bur, the lesions were etched and ethanol was applied to the lesions and it was determined if the lesion was still visible or not. Images were taken just prior infiltrant (Icon; DMG) application (T0), during the infiltration process (Tx) and when infiltration had ceased progressing or opacity disappearance was clinically apparent (Tmax). Surface-area measurements of the opacity and infiltrated area were calculated and the infiltration proportion (IPx) was calculated over the infiltration time. Results: Type 1 and positive ethanol test lesions showed significantly lower mean Tmax (3.4 min) in comparison with Type 2 and negative ethanol test lesions (9.9 min) [Student t-test/Fisher's exact test; p <.01]. A non-linear correlation was observed (R2 = 0.88) indicating that the IPx was rapid at the beginning of resin application, decreasing over time. Conclusion: In comparison with Type 1 and positive ethanol test lesions, Type 2 and negative ethanol test lesions require longer application time to infiltrate. Clinical significance: MIH-lesion type and the ‘ethanol test’ were reliable predictive factors for the application time required for infiltrating MIH lesions on permanent anterior teeth

The use of transillumination in mapping demarcated enamel opacities in anterior teeth:A cross-sectional study

Background: Despite intensive efforts for categorizing demarcated enamel opacities, often related to molar incisor hypomineralization (MIH), there is a lack of descriptive criteria aiming to describe them physically outside the scope of color and size. This is most likely due to the indices focusing on molar, not anterior, teeth. Aim: To map and classify demarcated lesions on permanent anterior teeth using reflected and transilluminated light. The association between classification and related lesion characteristics was also examined. Design: Permanent anterior teeth with demarcated opacities related to MIH were selected. For each tooth, standardized photographs were taken using transmitted and reflected light. Each lesion was mapped and classified according to its color, lesion size, surface integrity, and type. The data were analyzed using the chi-square and Fisher's exact tests. A logistic regression analysis was performed to identify the risk of PEB. Results: There were significant relationships between lesion size, color, and type with surface integrity. Lesion type and size were more important than lesion color for assessing the risk of PEB. There was also a significant relationship between lesion size and lesion color. Conclusions: Lesion size and type are significant clinical parameters for assessing the risk of PEB on enamel opacities related to MIH