225 research outputs found
Orbital operations study. Appendix B: Operational procedures
Operational procedures for each alternate approach for each interfacing activity of the orbital operations study are presented. The applicability of the procedures to interfacing element pairs is identified
Tunneling cosmological state revisited: Origin of inflation with a non-minimally coupled Standard Model Higgs inflaton
We suggest a path integral formulation for the tunneling cosmological state,
which admits a consistent renormalization and renormalization group (RG)
improvement in particle physics applications of quantum cosmology. We apply
this formulation to the inflationary cosmology driven by the Standard Model
(SM) Higgs boson playing the role of an inflaton with a strong non-minimal
coupling to gravity. In this way a complete cosmological scenario is obtained,
which embraces the formation of initial conditions for the inflationary
background in the form of a sharp probability peak in the distribution of the
inflaton field and the ongoing generation of the Cosmic Microwave Background
(CMB) spectrum on this background. Formation of this probability peak is based
on the same RG mechanism which underlies the generation of the CMB spectrum
which was recently shown to be compatible with the WMAP data in the Higgs mass
range . This brings to
life a convincing unification of quantum cosmology with the particle
phenomenology of the SM, inflation theory, and CMB observations.Comment: 18 pages, 3 figures, LaTe
Renormalization Group Flow in Scalar-Tensor Theories. II
We study the UV behaviour of actions including integer powers of scalar
curvature and even powers of scalar fields with Functional Renormalization
Group techniques. We find UV fixed points where the gravitational couplings
have non-trivial values while the matter ones are Gaussian. We prove several
properties of the linearized flow at such a fixed point in arbitrary dimensions
in the one-loop approximation and find recursive relations among the critical
exponents. We illustrate these results in explicit calculations in for
actions including up to four powers of scalar curvature and two powers of the
scalar field. In this setting we notice that the same recursive properties
among the critical exponents, which were proven at one-loop order, still hold,
in such a way that the UV critical surface is found to be five dimensional. We
then search for the same type of fixed point in a scalar theory with minimal
coupling to gravity in including up to eight powers of scalar curvature.
Assuming that the recursive properties of the critical exponents still hold,
one would conclude that the UV critical surface of these theories is five
dimensional.Comment: 14 pages. v.2: Minor changes, some references adde
Supergravity based inflation models: a review
In this review, we discuss inflation models based on supergravity. After
explaining the difficulties in realizing inflation in the context of
supergravity, we show how to evade such difficulties. Depending on types of
inflation, we give concrete examples, particularly paying attention to chaotic
inflation because the ongoing experiments like Planck might detect the tensor
perturbations in near future. We also discuss inflation models in Jordan frame
supergravity, motivated by Higgs inflation.Comment: 30 pages, invited review for Classical and Quantum Gravity, published
versio
Disparities in use of mental health and substance abuse services by Asian and Native Hawaiian/Other Pacific Islander women
The purpose of this study was to determine if disparities exist in lifetime utilization of mental health/substance abuse services among Asian, Native Hawaiian/Other Pacific Islander (NHOPI) and white mothers. The study sample was comprised of mothers assessed to be at-risk (n = 491) and not at-risk (n = 218) for child maltreatment in the Hawaii Healthy Start Program study. Multiple logistic regression models were used to test the effects of predisposing, need, and enabling factors on utilization of services. Results revealed that, among mothers with depressive symptoms, compared with whites, Asians and NHOPI were significantly less likely to have received services. There were no significant racial differences in use of mental health/substance use services by other factors. These results suggest that racial disparities exist in utilization of mental health/substance abuse services among mothers with depressive symptoms. Future research is needed to identify barriers and facilitators to accessing needed services for Asian and NHOPI women
Seaweed polysaccharide-based hydrogels used for the regeneration of articular cartilage
This manuscript provides an overview of the in vitro and in vivo studies reported in the
literature focusing on seaweed polysaccharides based hydrogels that have been proposed for
applications in regenerative medicine, particularly, in the field of cartilage tissue engineering.
For a better understanding of the main requisites for these specific applications, the main
aspects of the native cartilage structure, as well as recognized diseases that affect this tissue are
briefly described. Current available treatments are also presented to emphasize the need for
alternative techniques. The following part of this review is centered on the description of the
general characteristics of algae polysaccharides, as well as relevant properties required for
designing hydrogels for cartilage tissue engineering purposes. An in-depth overview of the
most well known seaweed polysaccharide, namely agarose, alginate, carrageenan and ulvan
biopolymeric gels, that have been proposed for engineering cartilage is also provided. Finally,
this review describes and summarizes the translational aspect for the clinical application of
alternative systems emphasizing the importance of cryopreservation and the commercial
products currently available for cartilage treatment.Authors report no declarations of interest. Authors thank the Portuguese Foundation for Science and Technology (FCT) for the PhD fellowship of Elena G. Popa (SFRH/BD/64070/2009) and research project (MIT/ECE/0047/2009). The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement no REGPOT-CT2012-316331-POLARIS
The use of mesenchymal stem cells for cartilage repair and regeneration: a systematic review.
BACKGROUND: The management of articular cartilage defects presents many clinical challenges due to its avascular, aneural and alymphatic nature. Bone marrow stimulation techniques, such as microfracture, are the most frequently used method in clinical practice however the resulting mixed fibrocartilage tissue which is inferior to native hyaline cartilage. Other methods have shown promise but are far from perfect. There is an unmet need and growing interest in regenerative medicine and tissue engineering to improve the outcome for patients requiring cartilage repair. Many published reviews on cartilage repair only list human clinical trials, underestimating the wealth of basic sciences and animal studies that are precursors to future research. We therefore set out to perform a systematic review of the literature to assess the translation of stem cell therapy to explore what research had been carried out at each of the stages of translation from bench-top (in vitro), animal (pre-clinical) and human studies (clinical) and assemble an evidence-based cascade for the responsible introduction of stem cell therapy for cartilage defects. This review was conducted in accordance to PRISMA guidelines using CINHAL, MEDLINE, EMBASE, Scopus and Web of Knowledge databases from 1st January 1900 to 30th June 2015. In total, there were 2880 studies identified of which 252 studies were included for analysis (100 articles for in vitro studies, 111 studies for animal studies; and 31 studies for human studies). There was a huge variance in cell source in pre-clinical studies both of terms of animal used, location of harvest (fat, marrow, blood or synovium) and allogeneicity. The use of scaffolds, growth factors, number of cell passages and number of cells used was hugely heterogeneous. SHORT CONCLUSIONS: This review offers a comprehensive assessment of the evidence behind the translation of basic science to the clinical practice of cartilage repair. It has revealed a lack of connectivity between the in vitro, pre-clinical and human data and a patchwork quilt of synergistic evidence. Drivers for progress in this space are largely driven by patient demand, surgeon inquisition and a regulatory framework that is learning at the same pace as new developments take place
Inflation from non-minimally coupled scalar field in loop quantum cosmology
The FRW model with non-minimally coupled massive scalar field has been
investigated in LQC framework. Considered form of the potential and coupling
allows applications to Higgs driven inflation. Out of two frames used in the
literature to describe such systems: Jordan and Einstein frame, the latter one
is applied. Specifically, we explore the idea of the Einstein frame being the
natural 'environment' for quantization and the Jordan picture having an
emergent nature. The resulting dynamics qualitatively modifies the standard
bounce paradigm in LQC in two ways: (i) the bounce point is no longer marked by
critical matter energy density, (ii) the Planck scale physics features the
'mexican hat' trajectory with two consecutive bounces and rapid expansion and
recollapse between them. Furthermore, for physically viable coupling strength
and initial data the subsequent inflation exceeds 60 e-foldings.Comment: Clarity improved. Replaced with revised version accepted in JCA
Correlation of the ratio of metastatic to non-metastatic cancer cases with the degree of socioeconomic deprivation among Texas counties
<p>Abstract</p> <p>Background</p> <p>Previous studies have demonstrated that cancer registrations and hospital discharge rate are closely correlated with census data-based socioeconomic deprivation indices. We hypothesized that communities with higher degrees of socioeconomic deprivation tend to have a higher ratio of metastatic to non-metastatic cancer cases (lung, breast, prostate, female genital system, colorectal cancers or all types of cancers combined). In this study, we investigate the potential link between this ratio and the Wellbeing Index (WI) among Texas counties.</p> <p>Results</p> <p>Cancer data in 2000 were provided by the Texas Cancer Registry, while data on the ten socioeconomic variables among the 254 Texas counties in 2000 for building the WI were obtained from U.S. Census Bureau. The ten socioeconomic status variables were subjected to the principal component analysis, and the first principal component scores were grouped into deciles for the WI (1 to 10) and the 254 Texas counties were classified into 10 corresponding groups. Weighted linear regression analyses and a Cochran-Armitage trend test were performed to determine the relationship between the ratio of age-adjusted metastatic to non-metastatic cancer incidence cases and WI. The ratios of metastatic to non-metastatic cases of female genital system cancer (<it>r</it><sup>2 </sup>= 0.84, <it>p </it>= 0.0002), all-type cancers (<it>r</it><sup>2</sup>= 0.73, <it>p </it>= 0.0017) and lung cancer (<it>r</it><sup>2</sup>= 0.54, <it>p </it>= 0.0156) at diagnosis were positively correlated with WI.</p> <p>Conclusions</p> <p>The ratios of metastatic to non-metastatic cases of all-type, female genital system and lung cancers at diagnosis were statistically correlated with socioeconomic deprivation. Potential mediators for the correlation warrant further investigation in order to reduce health disparities associated with socioeconomic inequality.</p
Search of scaling solutions in scalar-tensor gravity
We write new functional renormalization group equations for a scalar nonminimally coupled to gravity. Thanks to the choice of the parametrization and of the gauge fixing they are simpler than older equations and avoid some of the difficulties that were previously present. In three dimensions these equations admit, at least for sufficiently small fields, a solution that may be interpreted as a gravitationally dressed Wilson-Fisher fixed point. We also find for any dimension d>2 two analytic scaling solutions which we study for d=3 and d=4. One of them corresponds to the fixed point of the Einstein-Hilbert truncation, the others involve a nonvanishing minimal coupling
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