154 research outputs found
Violation Of The Rule In Decays
A strong violation of the rule has
experimentally been found in the decays [1]. In
this letter we will show that the order of magnitude of this violation can be
understood in terms of the pure quantum chromo dynamics corrections to the weak
interactions.Comment: Pages 1
N=8 gaugings revisited: an exhaustive classification
In this paper we reconsider, for N=8 supergravity, the problem of gauging the
most general electric subgroup.
We show that admissible theories are fully characterized by a single
algebraic equation to be satisfied by the embedding of the gauge group G within
the electric subalgebra SL(8,\IR) of E_{7(7)}. The complete set of solutions to
this equation contains 36 parameters. Modding by the action of SL(8,\IR)
conjugations that yield equivalent theories all continuous parameters are
eliminated except for an overall coupling constant and we obtain a discrete set
of orbits. This set is in one--to--one correspondence with 36 Lie subalgebras
of SL(8,\IR), corresponding to all possible real forms of the SO(8) Lie algebra
plus a set of contractions thereof. By means of our analysis we establish the
theorem that the N=8 gaugings constructed by Hull in the middle eighties
constitute the exhaustive set of models. As a corollary we show that there
exists a unique 7--dimensional abelian gauging. The corresponding abelian
algebra is not contained in the maximal abelian ideal of the solvable Lie
algebra generating the scalar manifold E_{7(7)}/SU(8).Comment: 1 LaTeX file, 41 pages, 3 eps-figure
D3-D7 Quark-Gluon Plasmas at Finite Baryon Density
We present the string dual to SU(Nc) N=4 SYM, coupled to Nf massless
fundamental flavors, at finite temperature and baryon density. The solution is
determined by two dimensionless parameters, both depending on the 't Hooft
coupling at the scale set by the temperature T:
, weighting the backreaction of the flavor
fields and , where is the
baryon density. For small values of these two parameters the solution is given
analytically up to second order. We study the thermodynamics of the system in
the canonical and grand-canonical ensembles. We then analyze the energy loss of
partons moving through the plasma, computing the jet quenching parameter and
studying its dependence on the baryon density. Finally, we analyze certain
"optical" properties of the plasma. The whole setup is generalized to non
abelian strongly coupled plasmas engineered on D3-D7 systems with D3-branes
placed at the tip of a generic singular Calabi-Yau cone. In all the cases,
fundamental matter fields are introduced by means of homogeneously smeared
D7-branes and the flavor symmetry group is thus a product of abelian factors.Comment: 27 pages; v2: 29 pages, 1 (new) figure, new section 4.4 on optical
properties, references, comments added; v3: eq. (3.19), comments and a
reference adde
The Two Faces of Anomaly Mediation
Anomaly mediation is a ubiquitous source of supersymmetry (SUSY) breaking
which appears in almost every theory of supergravity. In this paper, we show
that anomaly mediation really consists of two physically distinct phenomena,
which we dub "gravitino mediation" and "Kahler mediation". Gravitino mediation
arises from minimally uplifting SUSY anti-de Sitter (AdS) space to Minkowski
space, generating soft masses proportional to the gravitino mass. Kahler
mediation arises when visible sector fields have linear couplings to SUSY
breaking in the Kahler potential, generating soft masses proportional to beta
function coefficients. In the literature, these two phenomena are lumped
together under the name "anomaly mediation", but here we demonstrate that they
can be physically disentangled by measuring associated couplings to the
goldstino. In particular, we use the example of gaugino soft masses to show
that gravitino mediation generates soft masses without corresponding goldstino
couplings. This result naively violates the goldstino equivalence theorem but
is in fact necessary for supercurrent conservation in AdS space. Since
gravitino mediation persists even when the visible sector is sequestered from
SUSY breaking, we can use the absence of goldstino couplings as an unambiguous
definition of sequestering.Comment: 21 pages, 1 table; v2, references added, extended discussion in
introduction and appendix; v3, JHEP versio
Conservative management of retinoblastoma : Challenging orthodoxy without compromising the state of metastatic grace. "Alive, with good vision and no comorbidity"
Correction: Volume: 78 Article Number: 100857 DOI: 10.1016/j.preteyeres.2020.100857 Published: SEP 2020Retinoblastoma is lethal by metastasis if left untreated, so the primary goal of therapy is to preserve life, with ocular survival, visual preservation and quality of life as secondary aims. Historically, enucleation was the first successful therapeutic approach to decrease mortality, followed over 100 years ago by the first eye salvage attempts with radiotherapy. This led to the empiric delineation of a window for conservative management subject to a "state of metastatic grace" never to be violated. Over the last two decades, conservative management of retinoblastoma witnessed an impressive acceleration of improvements, culminating in two major paradigm shifts in therapeutic strategy. Firstly, the introduction of systemic chemotherapy and focal treatments in the late 1990s enabled radiotherapy to be progressively abandoned. Around 10 years later, the advent of chemotherapy in situ, with the capitalization of new routes of targeted drug delivery, namely intra-arterial, intravitreal and now intracameral injections, allowed significant increase in eye preservation rate, definitive eradication of radiotherapy and reduction of systemic chemotherapy. Here we intend to review the relevant knowledge susceptible to improve the conservative management of retinoblastoma in compliance with the "state of metastatic grace", with particular attention to (i) reviewing how new imaging modalities impact the frontiers of conservative management, (ii) dissecting retinoblastoma genesis, growth patterns, and intraocular routes of tumor propagation, (iii) assessing major therapeutic changes and trends, (iv) proposing a classification of relapsing retinoblastoma, (v) examining treatable/preventable disease-related or treatment-induced complications, and (vi) appraising new therapeutic targets and concepts, as well as liquid biopsy potentiality.Peer reviewe
Holographic Duals of Quark Gluon Plasmas with Unquenched Flavors
We review the construction of gravitational solutions holographically dual to
N=1 quiver gauge theories with dynamical flavor multiplets. We focus on the
D3-D7 construction and consider the finite temperature, finite quark chemical
potential case where there is a charged black hole in the dual solution.
Discussed physical outputs of the model include its thermodynamics (with
susceptibilities) and general hydrodynamic properties.Comment: Lecture presented at the Workshop "AdS/CFT and Novel Approaches to
Hadron and Heavy Ion Physics", Kavli Institute of Theoretical Physics
(KITPC), Beijing, China, 13 October 2010. Review article to be published in
Communications in Theoretical Physics. 27 pages, 2 figure
Association of blood pressure and arterial stiffness with cognition in 2 population-based child and adult cohorts
Background-High blood pressure levels and higher arterial stiffness have been shown to be associated with lower cognition during adulthood, possibly by accumulative changes over time. However, vascular factors may already affect the brain during early life. Methods and Results-We examined the relation between cognition and vascular factors within 5853 children from the Generation R Study (mean age 6.2 years) and 5187 adults from the Rotterdam Study (mean age 61.8 years). Diastolic and systolic blood pressure and arterial stiffness were assessed, the latter by measuring pulse-wave velocity and pulse pressure. For cognition, the Generation R Study relied on nonverbal intelligence, whereas the Rotterdam Study relied on a cognitive test battery to calculate the g-factor, a measure of global cognition. In the Generation R Study, standardized diastolic blood pressure showed a significant association with standardized nonverbal intelligence (ÎČ=-0.030, 95% confidence interval=[-0.054;-0.005]) after full adjustment. This association held up after excluding the top diastolic blood pressure decile (ÎČ=-0.042 [-0.075;-0.009]), suggesting that the relation holds in normotensives. Within the Rotterdam Stud
Screening effects on meson masses from holography
We study the spectra of scalar and vector mesons in four dimensional strongly
coupled SQCD-like theories in the Veneziano limit. The gauge theories describe
the low energy dynamics of intersecting D3 and D7-branes on the singular and
deformed conifold and their strong coupling regime can be explored by means of
dual fully backreacted supergravity backgrounds. The mesons we focus on are
dual to fluctuations of the worldvolume gauge field on a probe D7-brane in
these backgrounds. As we will comment in detail, the general occurrence of
various UV pathologies in the D3-D7 set-ups under study, forces us to adapt the
standard holographic recipes to theories with intrinsic cutoffs. Just as for
QED, the low energy spectra for mesonic-like bound states will be consistent
and largely independent of the UV cutoffs. We will study in detail how these
spectra vary with the number of the fundamental sea flavors and their mass.Comment: 30 pages + appendices, 10 figures; v2: subsection 3.3.3 and some
comments adde
Challenges and science-based implications for modern management and conservation of European ungulate populations
Wildlife management systems face growing challenges to cope with increasingly complex interactions between wildlife populations, the environment and human activities. In this position statement, we address the most important issues characterising current ungulate conservation and management in Europe. We present some key points arising from ecological research that may be critical for a reassessment of ungulate management in the future. Ecosystem . Population sustainability . Science-basedmanagement .Wildlifemanagement .Adaptive managemen
Dodecyl creatine ester improves cognitive function and identifies key protein drivers including KIF1A and PLCB1 in a mouse model of creatine transporter deficiency
Creatine transporter deficiency (CTD), a leading cause of intellectual disability is a result of the mutation in the gene encoding the creatine transporter SLC6A8, which prevents creatine uptake into the brain, causing mental retardation, expressive speech and language delay, autistic-like behavior and epilepsy. Preclinical in vitro and in vivo data indicate that dodecyl creatine ester (DCE) which increases the creatine brain content, might be a therapeutic option for CTD patients. To gain a better understanding of the pathophysiology and DCE treatment efficacy in CTD, this study focuses on the identification of biomarkers related to cognitive improvement in a Slc6a8 knockout mouse model (Slc6a8â/y) engineered to mimic the clinical features of CTD patients which have low brain creatine content. Shotgun proteomics analysis of 4,035 proteins in four different brain regions; the cerebellum, cortex, hippocampus (associated with cognitive functions) and brain stem, and muscle as a control, was performed in 24 mice. Comparison of the protein abundance in the four brain regions between DCE-treated intranasally Slc6a8â/y mice and wild type and DCE-treated Slc6a8â/y and vehicle group identified 14 biomarkers, shedding light on the mechanism of action of DCE. Integrative bioinformatics and statistical modeling identified key proteins in CTD, including KIF1A and PLCB1. The abundance of these proteins in the four brain regions was significantly correlated with both the object recognition and the Y-maze tests. Our findings suggest a major role for PLCB1, KIF1A, and associated molecules in the pathogenesis of CTD
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