Graduated dark energy: Observational hints of a spontaneous sign switch in the cosmological constant

We study the cosmological constant in the standard CDM model by introducing the graduated dark energy (gDE) characterised by a minimal dynamical deviation from the null inertial mass density of the in the form inert / < 0 with < 1 being a ratio of two odd integers, for which its energy density dynamically takes negative values in the nite past. For large negative values of , it creates a phenomenological model described by a smooth function that approximately describes the spontaneously switching sign in the late universe to become positive today. We confront the model with the latest combined observational data sets of PLK+BAO+SN+H. It is striking that the data predict bimodal posterior probability distributions for the parameters of the model along with large negative values; the new maximum signi cantly excludes the , and the old maximum contains the . The improvement in the goodness of the t for the reaches highly signi cant levels, 2 min = 6:4, for the new maxima, while it remains at insigni cant levels, 2 min . 0:02, for the old maxima. We show that, in contrast to the old maxima, which do not distinguish from the , the new maxima agree with the model-independent H0 measurements, high-precision Ly- data, and model-independent Omh2 diagnostic estimates. Our results provide strong hints of a spontaneous sign switch in the cosmological constant and lead us to conjecture that the universe has transitioned from AdS vacua to dS vacua, at a redshift z 2:32 and triggered the late-time acceleration, and suggests looking for such mechanisms in string theory constructions

Screening Λ in a new modified gravity model

Abstract We study a new model of Energy-Momentum Squared Gravity (EMSG), called Energy-Momentum Log Gravity (EMLG), constructed by the addition of the term $$f(T_{\mu \nu }T^{\mu \nu })=\alpha \ln (\lambda \,T_{\mu \nu }T^{\mu \nu })$$f(TμνTμν)=αln(λTμνTμν), envisaged as a correction, to the Einstein–Hilbert action with cosmological constant $$\Lambda$$Λ. The choice of this modification is made as a specific way of including new terms in the right-hand side of the Einstein field equations, resulting in constant effective inertial mass density and, importantly, leading to an explicit exact solution of the matter energy density in terms of redshift. We look for viable cosmologies, in particular, an extension of the standard $$\Lambda$$ΛCDM model. EMLG provides an effective dynamical dark energy passing below zero at large redshifts, accommodating a mechanism for screening $$\Lambda$$Λ in this region, in line with suggestions for alleviating some of the tensions that arise between observational data sets within the standard $$\Lambda$$ΛCDM model. We present a detailed theoretical investigation of the model and then constrain the free parameter $$\alpha '$$α′, a normalisation of $$\alpha$$α, using the latest observational data. The data does not rule out the $$\Lambda$$ΛCDM limit of our model ($$\alpha '= 0$$α′=0), but prefers slightly negative values of the EMLG model parameter ($$\alpha '= -0.032\pm 0.043$$α′=-0.032±0.043), which leads to the screening of $$\Lambda$$Λ. We also discuss how EMLG relaxes the persistent tension that appears in the measurements of $$H_0$$H0 within the standard $$\Lambda$$ΛCDM model.</jats:p

The Turkey Ig-like receptor family: identification, expression and function.

The chicken leukocyte receptor complex located on microchromosome 31 encodes the chicken Ig-like receptors (CHIR), a vastly expanded gene family which can be further divided into three subgroups: activating CHIR-A, bifunctional CHIR-AB and inhibitory CHIR-B. Here, we investigated the presence of CHIR homologues in other bird species. The available genome databases of turkey, duck and zebra finch were screened with different strategies including BLAST searches employing various CHIR sequences, and keyword searches. We could not identify CHIR homologues in the distantly related zebra finch and duck, however, several partial and complete sequences of CHIR homologues were identified on chromosome 3 of the turkey genome. They were designated as turkey Ig-like receptors (TILR). Using cDNA derived from turkey blood and spleen RNA, six full length TILR could be amplified and further divided according to the typical sequence features into one activating TILR-A, one inhibitory TILR-B and four bifunctional TILR-AB. Since the TILR-AB sequences all displayed the critical residues shown to be involved in binding to IgY, we next confirmed the IgY binding using a soluble TILR-AB1-huIg fusion protein. This fusion protein reacted with IgY derived from various gallinaceous birds, but not with IgY from other bird species. Finally, we tested various mab directed against CHIR for their crossreactivity with either turkey or duck leukocytes. Whereas no staining was detectable with duck cells, the CHIR-AB1 specific mab 8D12 and the CHIR-A2 specific mab 13E2 both reacted with a leukocyte subpopulation that was further identified as thrombocytes by double immunofluorescence employing B-cell, T-cell and thrombocyte specific reagents. In summary, although the turkey harbors similar LRC genes as the chicken, their distribution seems to be distinct with predominance on thrombocytes rather than lymphocytes

“I Think I Became a Swimmer Rather than Just Someone with a Disability Swimming Up and Down”: Paralympic Athletes Perceptions of Self and Identity Development

This is an Accepted Manuscript of an article published by Taylor & Francis Group in Disability and Rehabilitation on 27 September 2016, available online at:DOI: https://doi.org/10.1080/09638288.2016.1217074.Purpose: The purpose of this study was to explore the role of swimming on Paralympic athletes’ perceptions of self and identity development. Method: A hermeneutic phenomenological approach was taken. During semi-structured interviews five Paralympic swimmers (aged 20-24 years) were asked questions about their swimming career, perceptions of self, integration, and impairment. Interviews were audio-recorded and transcribed verbatim. Results: An Interpretative Phenomenological Analysis1 yielded three superordinate themes: a) ‘One of the crowd’; none of the participants viewed themselves as disabled, nor as supercrips; these perceptions stemmed from family-, school-, and swimming- related experiences, b) ‘Becoming me’; participation in swimming facilitated self- and social-acceptance, and identity development, and c) ‘A badge of honour’; swimming presented opportunity to present and reinforce a positive identity. Conclusions: Swimming experiences enabled the participants to enhance personal and social identities, integrate through pro-social mechanisms, and to develop a career path following retirement from competition.through pro-social mechanisms, and to develop a career path following retirement from competition.Peer reviewe

Endophyte Microbiome Diversity in Micropropagated Atriplex canescens and Atriplex torreyi var griffithsii

Microbial diversity associated with micropropagated Atriplex species was assessed using microscopy, isolate culturing, and sequencing. Light, electron, and confocal microscopy revealed microbial cells in aseptically regenerated leaves and roots. Clone libraries and tag-encoded FLX amplicon pyrosequencing (TEFAP) analysis amplified sequences from callus homologous to diverse fungal and bacterial taxa. Culturing isolated some seed borne endophyte taxa which could be readily propagated apart from the host. Microbial cells were observed within biofilm-like residues associated with plant cell surfaces and intercellular spaces. Various universal primers amplified both plant and microbial sequences, with different primers revealing different patterns of fungal diversity. Bacterial and fungal TEFAP followed by alignment with sequences from curated databases revealed 7 bacterial and 17 ascomycete taxa in A. canescens, and 5 bacterial taxa in A. torreyi. Additional diversity was observed among isolates and clone libraries. Micropropagated Atriplex retains a complex, intimately associated microbiome which includes diverse strains well poised to interact in manners that influence host physiology. Microbiome analysis was facilitated by high throughput sequencing methods, but primer biases continue to limit recovery of diverse sequences from even moderately complex communities

Theorems on existence and global dynamics for the Einstein equations

This article is a guide to theorems on existence and global dynamics of solutions of the Einstein equations. It draws attention to open questions in the field. The local-in-time Cauchy problem, which is relatively well understood, is surveyed. Global results for solutions with various types of symmetry are discussed. A selection of results from Newtonian theory and special relativity that offer useful comparisons is presented. Treatments of global results in the case of small data and results on constructing spacetimes with prescribed singularity structure or late-time asymptotics are given. A conjectural picture of the asymptotic behaviour of general cosmological solutions of the Einstein equations is built up. Some miscellaneous topics connected with the main theme are collected in a separate section.Comment: Submitted to Living Reviews in Relativity, major update of Living Rev. Rel. 5 (2002)

The Cosmological Constant

This is a review of the physics and cosmology of the cosmological constant. Focusing on recent developments, I present a pedagogical overview of cosmology in the presence of a cosmological constant, observational constraints on its magnitude, and the physics of a small (and potentially nonzero) vacuum energy.Comment: 50 pages. Submitted to Living Reviews in Relativity (http://www.livingreviews.org/), December 199

Dying on the Streets: Homeless Persons’ Concerns and Desires about End of Life Care

BACKGROUND: There is little understanding about the experiences and preferences at the end of life (EOL) for people from unique cultural and socioeconomic backgrounds. Homeless individuals are extreme examples of these overlooked populations; they have the greatest risk of death, encounter barriers to health care, and lack the resources and relationships assumed necessary for appropriate EOL care. Exploring their desires and concerns will provide insight for the care of this vulnerable and disenfranchised population, as well as others who are underserved. OBJECTIVE: Explore the concerns and desires for EOL care among homeless persons. DESIGN: Qualitative study utilizing focus groups. PARTICIPANTS: Fifty-three homeless persons recruited from agencies providing homeless services. MEASUREMENTS: In-depth interviews, which were audiotaped and transcribed. RESULTS: We present 3 domains encompassing 11 themes arising from our investigation, some of which are previously unreported. Homeless persons worried about dying and EOL care; had frequent encounters with death; voiced many unique fears, such as dying anonymously and undiscovered; favored EOL documentation, such as advance directives; and demonstrated ambivalence towards contacting family. They also spoke of barriers to EOL care and shared interventions to improve dying among the very poor and estranged. CONCLUSIONS: Homeless persons have significant personal experience and feelings about death, dying, and EOL care, much of which is different from those previously described in the EOL literature about other populations. These findings have implications not only for homeless persons, but for others who are poor and disenfranchised