Stability of the Einstein static universe in presence of vacuum energy

The Einstein static universe has played a central role in a number of emergent scenarios recently put forward to deal with the singular origin of the standard cosmological model. Here we study the existence and stability of the Einstein static solution in presence of vacuum energy corresponding to conformally-invariant fields. We show that the presence of vacuum energy stabilizes this solution by changing it to a centre equilibrium point, which is cyclically stable. This allows non-singular emergent cosmological models to be constructed in which initially the universe oscillates indefinitely about an initial Einstein static solution and is thus past eternal.Comment: Some references adde

The presentation of the mind-brain problem in leading psychiatry journals

Objective: The mind-brain problem (MBP) has marked implications for psychiatry, but has been poorly discussed in the psychiatric literature. This paper evaluates the presentation of the MBP in the three leading general psychiatry journals during the last 20 years. Methods: Systematic review of articles on the MBP published in the three general psychiatry journals with the highest impact factor from 1995 to 2015. The content of these articles was analyzed and discussed in the light of contemporary debates on the MBP. Results: Twenty-three papers, usually written by prestigious authors, explicitly discussed the MBP and received many citations (mean = 130). The two main categories were critiques of dualism and defenses of physicalism (mind as a brain product). These papers revealed several misrepresentations of theoretical positions and lacked relevant contemporary literature. Without further discussion or evidence, they presented the MBP as solved, dualism as an old-fashioned or superstitious idea, and physicalism as the only rational and empirically confirmed option. Conclusion: The MBP has not been properly presented and discussed in the three leading psychiatric journals in the last 20 years. The few articles on the topic have been highly cited, but reveal misrepresentations and lack of careful philosophical discussion, as well as a strong bias against dualism and toward a materialist/physicalist approach to psychiatry.

Willingness and ability to pay for artemisinin-based combination therapy in rural Tanzania

The aim of this study was to analyse willingness to pay (WTP) and ability to pay (ATP) for ACT for children below five years of age in a rural setting in Tanzania before the introduction of artemisinin-based combination therapy (ACT) as first-line treatment for uncomplicated malaria. Socio-economic factors associated with WTP and expectations on anti-malaria drugs, including ACT, were also explored. Structured interviews and focus group discussions were held with mothers, household heads, health-care workers and village leaders in Ishozi, Gera and Ishunju wards in north-west Tanzania in 2004. Contingent valuation method (CVM) was used with "take-it-or-leave-it" as the eliciting method, expressed as WTP for a full course of ACT for a child and households' opportunity cost of ACT was used to assess ATP. The study included descriptive analyses with multivariate adjustment for potential confounding factors. Among 265 mothers and household heads, 244 (92%, CI = 88%-95%) were willing to pay Tanzanian Shillings (TSh) 500 (US$0.46) for a child's dose of ACT, but only 55$ 6.0, which would represent 0.9% of the average total consumption expenditures as estimated from official data in 2001. The cost of non-subsidized ACT represented 7.0% of reported total annual expenditure on food and 33.0% of total annual expenditure on health care."Rapid effect," "no adverse effect" and "inexpensive" were the most desired features of an anti-malarial drug. WTP for ACT in this study was less than its real cost and a subsidy is, therefore, needed to enable its equitable affordability. The decision taken in Tanzania to subsidize Coartem fully at governmental health care facilities and at a consumer price of TSh 300-500 (US$ 0.28-0.46) at special designated shops through the programme of Accredited Drug Dispensing Outlets (ADDOs) appears to be well founded

Non-singular inflation with vacuum decay

On the basis of a semi-classical analysis of vacuum energy in an expanding spacetime, we describe a non-singular cosmological model in which the vacuum density decays with time, with a concomitant production of matter. During an infinitely long period we have an empty, inflationary universe, with H \approx 1. This primordial era ends in a fast phase transition, during which H and \Lambda decrease to nearly zero in a few Planck times, with release of a huge amount of radiation. The late-time scenario is similar to the standard model, with the radiation phase followed by a long dust era, which tends asymptotically to a de Sitter universe, with vacuum dominating again. An analysis of the redshift-distance relation for supernovas Ia leads to cosmological parameters in agreement with other current estimations.Comment: Work presented at IRGAC 2006, Barcelona, July 11-15 2006. To appear in a special issue of Journal of Physics

ANALYSIS OF CHARACTERISTICS OF BUSINESS INCUBATORS IN COLOMBIA: A Case Study

Based on the research methodology of case study, in this article we analyze the main characteristics that condition business’s survival of four business’s incubators in Colombia (Bucaramanga, Créame, ParqueSoft and Gestando). The researchers applied the guide of best practices of the business’s incubators of Nodriza as a tool for the exploratory analysis. The results reveal that 70% of the companies comply with this guide, allowing them to continue surviving at the domestic and international market.Business’s incubators; pillars of business’s survival; business networks; regional develop; entrepreneurship.

Physicochemical and biological properties of novel chlorhexidine‐loaded nanotube‐modified dentin adhesive

A commercially available three‐step (etch‐and‐rinse) adhesive was modified by adding chlorhexidine (CHX)‐loaded nanotubes (Halloysite®, HNT) at two concentrations (CHX10% and CHX20%). The experimental groups were: SBMP (unmodified adhesive, control), HNT (SBMP modified with HNT), CHX10 (SBMP modified with HNT loaded with CHX10%), and CHX20 (SBMP modified with HNT loaded with CHX20%). Changes in the degree of conversion (DC%), Knoop hardness (KHN), water sorption (WS), solubility (SL), antimicrobial activity, cytotoxicity, and anti‐matrix metalloproteinase [MMP‐1] activity (collagenase‐I) were evaluated. In regards to DC%, two‐way ANOVA followed by Tukey’s post‐hoc test revealed that only the factor “adhesive” was statistically significant (p 0.05). For Knoop microhardness, one‐way ANOVA followed by the Tukey’s test showed statistically significant differences when comparing HNT (20.82 ± 1.65) and CHX20% (21.71 ± 2.83) with the SBMP and CHX10% groups. All adhesives presented similar WS and cytocompatibility. The CHX‐loaded nanotube‐modified adhesive released enough CHX to inhibit the growth of S. mutans and L. casei. Adhesive eluates were not able to effectively inhibit MMP‐1 activity. The evaluation of higher CHX concentrations might be necessary to provide an effective and predictable MMP inhibition. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res B Part B, 2018. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 868–875, 2019.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/148225/1/jbmb34183_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/148225/2/jbmb34183.pd