University of Waterloo

About: University of Waterloo is a education organization based out in Waterloo, Ontario, Canada. It is known for research contribution in the topics: Population & Poison control. The organization has 36093 authors who have published 93906 publications receiving 2948139 citations. The organization is also known as: UW & uwaterloo.

Psychological Indicators of Balance Confidence: Relationship to Actual and Perceived Abilities

Abstract: Background. This study compares several psychological indicators of balance confidence in relation to physical performance, past and current experience, gender bias, and other perceptions of daily functioning. Methods. Sixty community-dwelling ambulatory elders (aged 65-95) were administered the Falls Efficacy Scale (FES), the Activities-Specific Balance Confidence Scale (ABC), and three dichotomous questions on fear of falling, activity avoidance, and perceived need for personal assistance to ambulate outdoors. Performance measures on walking (average speed) and balance (static posturography) were obtained on a subsample of 21 subjects. Results. Balance confidence assessed by the ABC and self-perceived need for personal assistance with outdoor ambulation were the only indicators significantly associated with the performance measures. As expected, perceived balance capabilities were more strongly related to current behavior (frequency of doing specific activities) than to past experience (fall history). Gender differences in self-report emerged for the global fear-of-falling indicator but not for the two efficacy ratings. Conclusions. Psychological indicators of balance confidence are important to measure both in conjunction with balance test performance and as a legitimate focus of rehabilitation. Of the various indicators assessed here, the dichotomous fear-of-falling question appears to have the least utility. Perceived need for personal assistance to ambulate outdoors has merit as an initial clinical screening question for discriminating persons on the basis of both physical ability and confidence. The ABC scale appears to have the greatest utility as an evaluative index for older persons at a moderate to high level of functioning.

Reentrant phase transitions in rotating anti–de Sitter black holes

Abstract: Introduction In view of the AdS/CFT correspondence, phase transitions in asymptotically AdS black holes allow for a dual interpretation in the thermal conformal field theory (CFT) living on the AdS boundary—the principal example being the well known radiation/Schwarzschild-AdS black hole Hawking–Page transition [1] which can be interpreted as a confinement/deconfinement phase transition in the dual quark gluon plasma [2] Charged [3–6] and rotating [7, 8] asymptotically AdS back holes possess an interesting feature—they allow for a first order small-blackhole/large-black-holephase (SBH/LBH) transition which is in many ways reminiscent of the liquid/gas transition of the Van der Waals fluid This superficial analogy was recently found more intriguing [9] by considering a thermodynamic analysis in an extended phase space where the cosmological constant is identified with thermodynamic pressure and its variations are included in the first law of black hole thermodynamics This notion emerges from geometric derivations of the Smarr formula [10] that i) imply the mass of an AdS black hole should be interpreted as the enthalpy of the spacetime and ii) allow for a computation of the conjugate thermodynamic volume Intensive and extensive quantities are now properly identified [9] and the SBH/LBH transition can be understood as a liquid/gas phase transition by employing Maxwell’s equal area law to the P V diagram Coexistence lines and critical exponents are then seen to match those of a Van der Waals fluid In this paper we report the finding of an interesting phenomena, observed previously in multicomponent fluids, eg, [11], of black hole reentrant phase transitions (RPTs) A system undergoes an RPT if a monotonic variation of any thermodynamic quantity results in two (or more) phase transitions such that the final state is macroscopically similar to the initial state We find for a certain range of pressures (and a given angular momentum) that a monotonic lowering of the temperature yields a large-small-large black hole transition, where we refer to the latter ‘large’ state as an intermediate black hole (IBH) This situation is accompanied by a discontinuity in the global minimum of the Gibbs free energy, referred to as a zeroth-order phase transition, a phenomenon seen in superfluidity and superconductivity [12], and recently for Born–Infeld black holes [13] We find the RPT to be generic for all rotating AdS black holes in d � 6 dimen

Smart Cities: A Survey on Data Management, Security, and Enabling Technologies

Abstract: Integrating the various embedded devices and systems in our environment enables an Internet of Things (IoT) for a smart city. The IoT will generate tremendous amount of data that can be leveraged for safety, efficiency, and infotainment applications and services for city residents. The management of this voluminous data through its lifecycle is fundamental to the realization of smart cities. Therefore, in contrast to existing surveys on smart cities we provide a data-centric perspective, describing the fundamental data management techniques employed to ensure consistency, interoperability, granularity, and reusability of the data generated by the underlying IoT for smart cities. Essentially, the data lifecycle in a smart city is dependent on tightly coupled data management with cross-cutting layers of data security and privacy, and supporting infrastructure. Therefore, we further identify techniques employed for data security and privacy, and discuss the networking and computing technologies that enable smart cities. We highlight the achievements in realizing various aspects of smart cities, present the lessons learned, and identify limitations and research challenges.

The impact of contact angle on the biocompatibility of biomaterials.

Abstract: Biomaterials may be defined as artificial materials that can mimic, store, or come into close contact with living biological cells or fluids and are becoming increasingly popular in the medical, biomedical, optometric, dental, and pharmaceutical industries. Within the ophthalmic industry, the best example of a biomaterial is a contact lens, which is worn by approximately 125 million people worldwide. For biomaterials to be biocompatible, they cannot illicit any type of unfavorable response when exposed to the tissue they contact. A characteristic that significantly influences this response is that related to surface wettability, which is often determined by measuring the contact angle of the material. This article reviews the impact of contact angle on the biocompatibility of tissue engineering substrates, blood-contacting devices, dental implants, intraocular lenses, and contact lens materials.