Gravastars and Black Holes of Anisotropic Dark Energy

Dynamical models of prototype gravastars made of anisotropic dark energy are constructed, in which an infinitely thin spherical shell of a perfect fluid with the equation of state $p = (1-\gamma)\sigma$ divides the whole spacetime into two regions, the internal region filled with a dark energy fluid, and the external Schwarzschild region. The models represent "bounded excursion" stable gravastars, where the thin shell is oscillating between two finite radii, while in other cases they collapse until the formation of black holes. Here we show, for the first time in the literature, a model of gravastar and formation of black hole with both interior and thin shell constituted exclusively of dark energy. Besides, the sign of the parameter of anisotropy ($p_t - p_r$) seems to be relevant to the gravastar formation. The formation is favored when the tangential pressure is greater than the radial pressure, at least in the neighborhood of the isotropic case ($\omega=-1$).Comment: 16 pages, 8 figures. Accepted for publication in Gen. Rel. Gra

The normal ranges of cardiovascular parameters measured using the ultrasonic cardiac output monitor

The ultrasonic cardiac output monitor (USCOM) is a noninvasive transcutaneous continuous wave Doppler method for assessing hemodynamics. There are no published reference ranges for normal values in adults (aged 18– 60 years) for this device. This study aimed to (1) measure cardiovascular indices using USCOM in healthy adults aged 18–60 years; (2) combine these data with those for healthy children (aged 0–12), adolescents (aged 12–18), and the elderly (aged over 60) from our previously published studies in order to present normal ranges for all ages, and (3) establish normal ranges of USCOM-derived variables according to both weight and age. This was a population- based cross-sectional observational study of healthy Chinese subjects aged 0.5–89 years in Hong Kong. USCOM scans were performed on all subjects, to produce measurements including stroke volume, cardiac output, and systemic vascular resistance. Data from previously published studies (children, adolescents, and the elderly) were included. Normal ranges were defined as lying between the 2.5th and 97.5th percentiles. A total of 2218 subjects were studied (mean age = 16.4, range = 0.5–89; 52% male). From previous studies, 1197 children (aged 0–12, 55% male), 590 adolescents (aged 12–18, 49% male), and 77 elderly (aged 60–89, 55% male) were included. New data were collected from 354 adults aged 18–60 (47% male). Normal ranges are presented according to age and weight. We present comprehensive normal ranges for hemodynamic parameters obtained with USCOM in healthy subjects of all ages from infancy to the elderly

Understanding General Activity Motivation for Persons with Stroke—A Reversal Theory Perspective

Introduction: Motivation is the barrier identified for clients with stroke to reintegrate community living. Reversal Therapy may help to understand the pattern of bipolar variations of motivational factors. This study analyzed the general activity motivation of clients with stroke and their relationship with community participation and mental wellbeing. Methodology: Sampling of 115 subjects including 30 stroke clients and 85 normal subjects. Measurements included the validated Chinese version of General Activity Motivation Measure (GAMM), Community Integration Questionnaire (CIQ) & Short Warwick Edinburgh Mental Wellbeing Scale (SWEMWBS). Results: In GAMM, the normal group scores (Mean 50.09 SD 5.79) higher then clients with stroke (Mean 46.09; SD 8.00) (p < 0.05). GAMM correlated positively with CIQ and SWEMWBS (p < 0.05). Four factors identified under GAMM namely Means-end, Relationship, Rules and Transactions that identified with Reversal Theory. Reversals between poles of each domain evidenced between two groups. “Acquiring new experiences” was strong predictor for community integration. Conclusion: Reversal Theory is useful to explain motivational changes among clients with stroke. To develop chances of “new experiences”, “feel accomplishment every day”, “get out of house regularly” and “to do the things that they can enjoy” at “their own pace” are the motivators for reintegrate into community living

Thermodynamics of a Kerr Newman de Sitter Black Hole

We compute the conserved quantities of the four-dimensional Kerr-Newman-dS (KNdS) black hole through the use of the counterterm renormalization method, and obtain a generalized Smarr formula for the mass as a function of the entropy, the angular momentum and the electric charge. The first law of thermodynamics associated to the cosmological horizon of KNdS is also investigated. Using the minimal number of intrinsic boundary counterterms, we consider the quasilocal thermodynamics of asymptotic de Sitter Reissner-Nordstrom black hole, and find that the temperature is equal to the product of the surface gravity (divided by $2\pi$) and the Tolman redshift factor. We also perform a quasilocal stability analysis by computing the determinant of Hessian matrix of the energy with respect to its thermodynamic variables in both the canonical and the grand-canonical ensembles and obtain a complete set of phase diagrams. We then turn to the quasilocal thermodynamics of four-dimensional Kerr-Newman-de Sitter black hole for virtually all possible values of the mass, the rotation and the charge parameters that leave the quasilocal boundary inside the cosmological event horizon, and perform a quasilocal stability analysis of KNdS black hole.Comment: REVTEX4, 12 pages, 12 figures, references added and some points in Sec II have been clarified, version to appear in Can. J. Phy

An Overview of the Rising Challenges in Implementing Industry 4.0

Industry 4.0 is the fourth industrial revolution that was first introduced in Germany which then becomes a trend of future manufacturing industries. The Industry 4.0 also referred as the umbrella concept for new industrial paradigm which consists of a number of future industry characteristics, were related to cyber-physical systems (CPS), internet of things (IoT), internet of services (IoS), robotics, big data, cloud manufacturing and augmented reality. By adopting these technologies as the key development in more intelligent manufacturing processes including devices, machines, modules, and products, the process of information exchange, action and control will stimulate each other, subsequently to an intelligent manufacturing environment. However, in order to fully utilize the advantages of industry 4.0, there are some challenges that need to be overcome. This paper reviews the challenges in implementing Industry 4.0. The literatures found in this paper mainly from Google Scholar, Science Direct and Emerald. In short, the challenges can be imparted into seven major categories. There are data management and Integration, knowledge-driven, process, security, capital, workforce, and education

The effects of mindfulness-based stress reduction program on the mental health of family caregivers: a randomized controlled trial

&lt;b&gt;Background&lt;/b&gt; Caregivers of people with chronic conditions are more likely than non-caregivers to have depression and emotional problems. Few studies have examined the effectiveness of mindfulness-based stress reduction (MBSR) in improving their mental well-being. &lt;p&gt;&lt;/p&gt; &lt;b&gt;Methods&lt;/b&gt; Caregivers of persons with chronic conditions who scored 7 or above in the Caregiver Strain Index were randomly assigned to the 8-week MBSR group (n = 70) or the self-help control group (n = 71). Validated instruments were used to assess the changes in depressive and anxiety symptoms, quality of life, self-efficacy, self-compassion and mindfulness. Assessments were conducted at baseline, post-intervention and at the 3-month follow-up. &lt;p&gt;&lt;/p&gt; &lt;b&gt;Results &lt;/b&gt;Compared to the participants in the control group, participants in the MBSR group had a significantly greater decrease in depressive symptoms at post-intervention and at 3 months post-intervention (p &lt; 0.01). The improvement in state anxiety symptoms was significantly greater among participants in the MBSR group than those of the control group at post-intervention (p = 0.007), although this difference was not statistically significant at 3 months post-intervention (p = 0.084). There was also a statistically significant larger increase in self-efficacy (controlling negative thoughts; p = 0.041) and mindfulness (p = 0.001) among participants in the MBSR group at the 3-month follow-up compared to the participants in the control group. No statistically significant group effects (MBSR vs. control) were found in perceived stress, quality of life or self-compassion. &lt;p&gt;&lt;/p&gt; &lt;b&gt;Conclusions &lt;/b&gt;MBSR appears to be a feasible and acceptable intervention to improve mental health among family caregivers with significant care burden, although further studies that include an active control group are needed to make the findings more conclusive

Stable Gravastars of Anisotropic Dark Energy

Dynamical models of prototype gravastars made of phantom energy are constructed, in which an infinitely thin spherical shell of a perfect fluid with the equation of state $p = (1-\gamma)\sigma$ divides the whole spacetime into two regions, the internal region filled with a dark energy (or phantom) fluid, and the external Schwarzschild region. It is found that in some cases the models represent the "bounded excursion" stable gravastars, where the thin shell is oscillating between two finite radii, while in other cases they collapse until the formation of black holes or normal stars. In the phase space, the region for the "bounded excursion" gravastars is very small in comparison to that of black holes, but not empty, as found in our previous papers. Therefore, although the existence of gravastars can not be completely excluded from current analysis, the opposite is not possible either, that is, even if gravastars exist, they do not exclude the existence of black holes.Comment: 35 pages, 43 figures, added some clarifying texts and corrected some typos, accepted for publication in JCA

Second harmonic generation and photochromic grating in polyurethane films containing diazo isoxazole chromophore

The chromophoric intermediate: 2,2′-({4-[(E)-(5-methylisoxazol-3-yl)diazenyl]phenyl}-imino)diethanol was used in polyaddition reaction with di-isocyanate to obtain a new polyurethane polymeric material showing nonlinear optical and photochromic properties. The maximum absorption band of the polymer film was at 418 nm. The illumination of the film with crossed beams of the 488 nm Ar+ laser yielded surface relief grating of regular structure. Measurement of the frequency doubling signal with 1064 nm laser indicated the polymer as interesting material for photooptical applications. The measured nonlinear optical coefficient, d33, reached 90.2 pm/V

Charged black holes in generalized dilaton-axion gravity

We study generic Einstein-Maxwell-Kalb-Ramond-dilaton actions, and derive conditions under which they give rise to static, spherically symmetric black hole solutions. We obtain new asymptotically flat and non-flat black hole solutions which are in general electrically and magnetically charged. They have positive definite and finite quasi-local masses. Existing non-rotating black hole solutions (including those appearing in low energy string theory) are recovered in special limits.Comment: Replaced with revised version, 33 pages, No figure