556 research outputs found
Symmetric arrangement of mitochondria:plasma membrane contacts between adjacent photoreceptor cells regulated by Opa1
Mitochondria are known to play an essential role in photoreceptor function and survival that enables normal vision. Within photoreceptors, mitochondria are elongated and extend most of the inner-segment length, where they supply energy for protein synthesis and the phototransduction machinery in the outer segment, as well as acting as a calcium store. Here, we examined the arrangement of the mitochondria within the inner segment in detail using three-dimensional (3D) electron microscopy techniques and show they are tethered to the plasma membrane in a highly specialized arrangement. Remarkably, mitochondria and their cristae openings align with those of neighboring inner segments. The pathway by which photoreceptors meet their high energy demands is not fully understood. We propose this to be a mechanism to share metabolites and assist in maintaining homeostasis across the photoreceptor cell layer. In the extracellular space between photoreceptors, Müller glial processes were identified. Due to the often close proximity to the inner-segment mitochondria, they may, too, play a role in the inner-segment mitochondrial arrangement as well as metabolite shuttling. OPA1 is an important factor in mitochondrial homeostasis, including cristae remodeling; therefore, we examined the photoreceptors of a heterozygous Opa1 knockout mouse model. The cristae structure in the Opa1+/− photoreceptors was not greatly affected, but the mitochondria were enlarged and had reduced alignment to neighboring inner-segment mitochondria. This indicates the importance of key regulators in maintaining this specialized photoreceptor mitochondrial arrangement
A study of the etapipi channel produced in central pp interactions at 450 GeV/c
The reaction pp -> pf (eta pi pi) ps has been studied at 450 GeV/c. There is
clear evidence for an a2(1320)pi decay mode of the eta2(1645) and eta2(1870).
In addition, there is evidence for an a0(980)pi$ decay mode of both resonances
and an f2(1270)eta decay mode of the eta2(1870). No evidence is found for a JPC
= 2++ a2(1320)pi wave.Comment: 15 pages, Latex, 4 Figures Branching ratio a2pi /f2 eta correcte
A search for charmonium states produced in central pp interactions at 450 GeV/c
A search for centrally produced charmonium states has been presented. There
is no significant evidence for any charmonium production. An upper limit of 2
nb is found for the cross section of chic production using the decay chic(1P)->
J/psi gamma.Comment: 10 pages, Latex, 4 Figure
A study of the f0(1370), f0(1500), f0(2000) and f2(1950) observed in the centrally produced 4pi final states
The production and decay properties of the f0(1370), f0(1500), f0(2000) and
f2(1950) have been studied in central pp interactions at 450 GeV/c. The dPT,
phi and |t| distributions of these resonances are presented. For the J = 0
states, the f0(1370) and f0(2000) have similar dPT and phi dependences. These
are different to the dPT and phi dependences of the f0(980), f0(1500) and
f0(1710). For the J = 2 states the f2(1950) has different dependences to the
f2(1270) and f2'(1520). This shows that the dPT and phi dependences are not
just J phenomena.Comment: 14 pages, Latex, 4 Figure
A study of the centrally produced pi0pi0pi0 channel in pp interactions at 450 GeV/c
The reaction pp -> pf (pi0pi0pi0) ps has been studied at 450 GeV/c. The
pi0pi0pi0 effective mass spectrum shows clear eta(547) and pi2(1670) signals.
Branching ratios for the eta(547) and pi_2(1670) are given as well as upper
limits for the decays of the omega(782), a1(1260) and a2(1320) into 3pi0.Comment: 10 pages, Latex, 4 Figure
A coupled channel analysis of the centrally produced K+K- and pi+pi- final states in pp interactions at 450 GeV/c
A coupled channel analysis of the centrally produced K+K- and pi+pi- final
states has been performed in pp collisions at an incident beam momentum of 450
GeV/c. The pole positions and branching ratios to pipi and KK of the f0(980),
f0(1370), f0(1500) and f0(1710) have been determined. A systematic study of the
production properties of all the resonances observed in the pi+pi- and K+K-
channels has been performed.Comment: 16 pages, Latex, 5 Figure
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A systematic review of frameworks for the interrelationships of mental health evidence and policy in low- and middle-income countries
Background: The interrelationships between research evidence and policy-making are complex. Different theoretical frameworks exist to explain general evidence–policy interactions. One largely unexplored element of these interrelationships is how evidence interrelates with, and influences, policy/political agenda-setting. This review aims to identify the elements and processes of theories, frameworks and models on interrelationships of research evidence and health policy-making, with a focus on actionability and agenda-setting in the context of mental health in low- and middle-income countries (LMICs).
Methods: A systematic review of theories was conducted based on the BeHeMOTh search method, using a tested and refined search strategy. Nine electronic databases and other relevant sources were searched for peer-reviewed and grey literature. Two reviewers screened the abstracts, reviewed full-text articles, extracted data and performed quality assessments. Analysis was based on a thematic analysis. The included papers had to present an actionable theoretical framework/model on evidence and policy interrelationships, such as knowledge translation or evidence-based policy, specifically target the agenda-setting process, focus on mental health, be from LMICs and published in English.
Results: From 236 publications included in the full text analysis, no studies fully complied with our inclusion criteria. Widening the focus by leaving out ‘agenda-setting’, we included ten studies, four of which had unique conceptual frameworks focusing on mental health and LMICs but not agenda-setting. The four analysed frameworks confirmed research gaps from LMICs and mental health, and a lack of focus on agenda-setting. Frameworks and models from other health and policy areas provide interesting conceptual approaches and lessons with regards to agenda-setting.
Conclusion: Our systematic review identified frameworks on evidence and policy interrelations that differ in their elements and processes. No framework fulfilled all inclusion criteria. Four actionable frameworks are applicable to mental health and LMICs, but none specifically target agenda-setting. We have identified agenda-setting as a research theory gap in the context of mental health knowledge translation in LMICs. Frameworks from other health/policy areas could offer lessons on agenda-setting and new approaches for creating policy impact for mental health and to tackle the translational gap in LMICs
Experimental evidence for a vector-like behaviour of Pomeron exchange
Evidence is presented that the Pomeron act as a non-conserved vector current.
A study has been made of the azimuthal angle phi, which is defined as the angle
between the pT vectors of the two outgoing protons, in the reaction pp ->
pp(X0) for those resonances (X0) which are compatible with being produced by
double Pomeron exchange. These distributions have been compared with a model
which describes the Pomeron as a non-conserved vector current and a qualitative
agreement is found. In addition, when one of the particles exchanged is known
to have spin 0, namely pi-Pomeron exchange, the phi distribution is flat.Comment: 13 pages, Latex, 4 Figure
Spectroscopic analysis of the B/Be visual binary HR 1847
We studied both components of a slightly overlooked visual binary HR 1847
spectroscopically to determine its basic physical and orbital parameters. Basic
stellar parameters were determined by comparing synthetic spectra to the
observed echelle spectra, which cover both the optical and near-IR regions. New
observations of this system used the Ond\v{r}ejov and Rozhen 2-m telescopes and
their coud\'e spectrographs. Radial velocities from individual spectra were
measured and then analysed with the code {\FOTEL} to determine orbital
parameters. The spectroscopic orbit of HR 1847A is presented for the first
time. It is a single-lined spectroscopic binary with a B-type primary, a period
of 719.79 days, and a highly eccentric orbit with e=0.7. We confirmed that HR
1847B is a Be star. Its H\alpha emission significantly decreased from 2003 to
2008. Both components have a spectral type B7-8 and luminosity class IV-V.Comment: Astronomy and Astrophysics, accepte
Centrality dependence of the expansion dynamics in Pb-Pb collisions at 158 A GeV/c
Two-particle correlation functions of negatively charged hadrons from Pb-Pb
collisions at 158 GeV/c per nucleon have been measured by the WA97 experiment
at the CERN SPS. A Coulomb correction procedure that assumes an expanding
source has been implemented. Within the framework of an expanding thermalized
source model the size and dynamical state of the collision fireball at
freeze-out have been reconstructed as a function of the centrality of the
collision. Less central collisions exhibit a different dynamics than central
ones: both transverse and longitudinal expansion velocities are slower, the
expansion duration is shorter and the system freezes out showing smaller
dimensions and higher temperature.Comment: 22 pages, 11 figures, Te
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