310 research outputs found
The A+B -> 0 annihilation reaction in a quenched random velocity field
Using field-theoretic renormalization group methods the long-time behaviour
of the A+B -> 0 annihilation reaction with equal initial densities n_A(0) =
n_B(0) = n_0 in a quenched random velocity field is studied. At every point (x,
y) of a d-dimensional system the velocity v is parallel or antiparallel to the
x-axis and depends on the coordinates perpendicular to the flow. Assuming that
v(y) have zero mean and short-range correlations in the y-direction we show
that the densities decay asymptotically as n(t) ~ A n_0^(1/2) t^(-(d+3)/8) for
d<3. The universal amplitude A is calculated at first order in \epsilon = 3-d.Comment: 19 pages, LaTeX using IOP-macros, 5 eps-figures. It is shown that the
amplitude of the density is universal, i.e. independent of the reaction rat
A ânearâlife experienceâ: lived experiences of spirituality from the perspective of people who have been subject to inpatient psychiatric care
Aims: To describe lived experiences of spirituality from the perspective of people who have been subject to inpatient psychiatric care and to interpret these experiences from an understanding of health as dialectical.
Methods: After approval from a regional ethical board,eleven participants were recruited from two organisations for people with mental health problems. Participants were asked to narrate about spiritual experiences and occasions where such experiences had come close. The transcribed interviews were analysed by means of a phenomenological hermeneutical approach.
Findings: A structural analysis of the text resulted in three themes; perceiving the presence of something extra mundane, making sense of reality and struggling for acceptance. The comprehensive understanding highlights spiritual experiences as going beyond religion, even though religious experiences appear as part of it. These experiences can indeed be a resource contributing to experiences of hope, connectedness, meaning and coherence in life. However, they can also give rise to doubt, anxiety and feelings of loneliness and hopelessness. Rather than understanding spiritual experiences as being either âgoodâ or âbadâ, we could approach spirituality as something that is always present in alternate and inter-related forms. Metaphorically, this could be understood as a ânear-life experienceâ, summarising participantsâexperiences related to their struggle with issues related to suffering and health which are simultaneously present.
Conclusions: If psychiatric nurses could approach this complexity and, without being judgemental, explore seemingly positive and negative experiences of spirituality as dialectically related to each other, rather than viewing them as either resources or problems, this could contribute to insiderness care and hopefully also support people who struggle with these experiences to seek help when needed
N-Acyl Dehydrotyrosines, Typrosinase Inhibitors from the Marine Bacteriu, Thalasssotalea sp. PP2-459
Thalassotalic acids AâC and thalassotalamides A and B are new N-acyl dehydrotyrosine derivatives produced by Thalassotalea sp. PP2-459, a Gram-negative bacterium isolated from a marine bivalve aquaculture facility. The structures were elucidated via a combination of spectroscopic analyses emphasizing two-dimensional NMR and high-resolution mass spectrometric data. Thalassotalic acid A (1) displays in vitro inhibition of the enzyme tyrosinase with an IC50 value (130 ÎźM) that compares favorably to the commercially used control compounds kojic acid (46 ÎźM) and arbutin (100 ÎźM). These are the first natural products reported from a bacterium belonging to the genus Thalassotalea
High Efficiency Plastic Scintillator Detector with Wave-Length Shifting Fiber Readout for the GLAST Large Area Telescope
This paper describes the design and performance studies of the scintillator tile detectors for the Anti-Coincidence Detector (ACD) of the Large Area Telescope (LAT) on the Gamma ray Large Area Space Telescope (GLAST), scheduled for launch in early 2008. The scintillator tile detectors utilize wavelength shifting fibers and have dual photomultiplier tube (PMT) readout. The design requires highly efficient and uniform detection of singly charged relativistic particles over the tile area and must meet all requirements for a launch, as well as operation in a space environment. We present here the design of three basic types of tiles used in the ACD, ranging in size from approx.450 sq cm to approx.2500 sq cm, all 1 cm thick, with different shapes, and with photoelectron yield of approx. 20 photoelectrons per minimum ionizing particle (mip) at normal tile incidence, uniform over the tile area. Some tiles require flexible clear fiber cables up to 1.5 m long to deliver scintillator light to remotely located PMT
Recommended from our members
Musashi-2 controls cell fate, lineage bias, and TGF-β signaling in HSCs
Hematopoietic stem cells (HSCs) are maintained through the regulation of symmetric and asymmetric cell division. We report that conditional ablation of the RNA-binding protein Msi2 results in a failure of HSC maintenance and engraftment caused by a loss of quiescence and increased commitment divisions. Contrary to previous studies, we found that these phenotypes were independent of Numb. Global transcriptome profiling and RNA target analysis uncovered Msi2 interactions at multiple nodes within pathways that govern RNA translation, stem cell function, and TGF-β signaling. Msi2-null HSCs are insensitive to TGF-βâmediated expansion and have decreased signaling output, resulting in a loss of myeloid-restricted HSCs and myeloid reconstitution. Thus, Msi2 is an important regulator of the HSC translatome and balances HSC homeostasis and lineage bias
Uropathogenic Escherichia coli Metabolite-Dependent Quiescence and Persistence May Explain Antibiotic Tolerance during Urinary Tract Infection
In the present study, it is shown that although Escherichia coli CFT073, a human uropathogenic (UPEC) strain, grows in liquid glucose M9 minimal medium, it fails to grow on glucose M9 minimal medium agar plates seeded with â¤106 CFU. The cells on glucose plates appear to be in a âquiescentâ state that can be prevented by various combinations of lysine, methionine, and tyrosine. Moreover, the quiescent state is characteristic of ~80% of E. coli phylogenetic group B2 multilocus sequence type 73 strains, as well as 22.5% of randomly selected UPEC strains isolated from community-acquired urinary tract infections in Denmark. In addition, E. coli CFT073 quiescence is not limited to glucose but occurs on agar plates containing a number of other sugars and acetate as sole carbon sources. It is also shown that a number of E. coliCFT073 mini-Tn5 metabolic mutants (gnd, gdhA, pykF, sdhA, and zwf) are nonquiescent on glucose M9 minimal agar plates and that quiescence requires a complete oxidative tricarboxylic acid (TCA) cycle. In addition, evidence is presented that, although E. coli CFT073 quiescence and persistence in the presence of ampicillin are alike in that both require a complete oxidative TCA cycle and each can be prevented by amino acids, E. coli CFT073 quiescence occurs in the presence or absence of a functional rpoS gene, whereas maximal persistence requires a nonfunctional rpoS. Our results suggest that interventions targeting specific central metabolic pathways may mitigate UPEC infections by interfering with quiescence and persistence
Uropathogenic <i>Escherichia coli</i> metabolite-dependent quiescence and persistence may explain antibiotic tolerance during urinary tract infection
ABSTRACT In the present study, it is shown that although Escherichia coli CFT073, a human uropathogenic (UPEC) strain, grows in liquid glucose M9 minimal medium, it fails to grow on glucose M9 minimal medium agar plates seeded with â¤106 CFU. The cells on glucose plates appear to be in a âquiescentâ state that can be prevented by various combinations of lysine, methionine, and tyrosine. Moreover, the quiescent state is characteristic of ~80% of E. coli phylogenetic group B2 multilocus sequence type 73 strains, as well as 22.5% of randomly selected UPEC strains isolated from community-acquired urinary tract infections in Denmark. In addition, E. coli CFT073 quiescence is not limited to glucose but occurs on agar plates containing a number of other sugars and acetate as sole carbon sources. It is also shown that a number of E. coli CFT073 mini-Tn5 metabolic mutants (gnd, gdhA, pykF, sdhA, and zwf) are nonquiescent on glucose M9 minimal agar plates and that quiescence requires a complete oxidative tricarboxylic acid (TCA) cycle. In addition, evidence is presented that, although E. coli CFT073 quiescence and persistence in the presence of ampicillin are alike in that both require a complete oxidative TCA cycle and each can be prevented by amino acids, E. coli CFT073 quiescence occurs in the presence or absence of a functional rpoS gene, whereas maximal persistence requires a nonfunctional rpoS. Our results suggest that interventions targeting specific central metabolic pathways may mitigate UPEC infections by interfering with quiescence and persistence. IMPORTANCE Recurrent urinary tract infections (UTIs) affect 10 to 40% of women. In up to 77% of those cases, the recurrent infections are caused by the same uropathogenic E. coli (UPEC) strain that caused the initial infection. Upon infection of urothelial transitional cells in the bladder, UPEC appear to enter a nongrowing quiescent intracellular state that is thought to serve as a reservoir responsible for recurrent UTIs. Here, we report that many UPEC strains enter a quiescent state when â¤106 CFU are seeded on glucose M9 minimal medium agar plates and show that mutations in several genes involved in central carbon metabolism prevent quiescence, as well as persistence, possibly identifying metabolic pathways involved in UPEC quiescence and persistence in vivo
Probation migration(s): Examining occupational culture in a turbulent field
In June 2014 approx. 54 per cent of the total probation service workforce in England and Wales were transferred to the newly created Community Rehabilitation Companies (CRCs) as part of the governmentâs plans to establish a market for offender management services. This marked the beginning of one of the largest and most significant migrations of criminal justice staff from the public to the private sector in England and Wales. This article presents findings from an ethnographic study of the formation of one of these CRCs through to the period immediately following the transfer into private ownership. The authors discuss the key features of this migration which are identified as âsplitting and fracturingâ, âadapting and formingâ and âexiting or accommodationâ. It is contended that this development not only has significant implications for the future of probation services but also provides a unique example of the impact on an occupational culture of migration from the public to the private sector
Deathscapes of Settler Colonialism : The necro-settlement of Stoney Creek, Ontario, Canada
This is the Accepted Manuscript of an article published by Taylor & Francis Group in annals of Association of American Geographers on 23 January 2018, available online https://doi.org/10.1080/24694452.2017.1406327. The Accepted Manuscript is under embargo until 23 January 2019.This article considers the influence of burials and memorials to colonial soldiers from an earlier era on contemporary social and cultural landscapes in Canada. Through the example of a landscape centered on Smithâs Knoll, a burial ground for war dead from the British-American War of 1812, it explores the process of necro-settlement: the strengthening of settler colonial claims to land based on the development of complex, meaningladen landscapes of dead and memory. This article consists of three parts: The first situates geographical studies of deathscapes alongside theories about settler colonialism through intersecting discourses of land use. The second includes a settler colonial microhistorical geography of Smithâs Knoll and the local deathscape that surrounds it. The third section draws on this case study to reveal new perspectives on the role of burial and memorial in settler colonial place-making and the erasure of Indigenous histories and peoples.Peer reviewedFinal Accepted Versio
- âŚ