A glimpse at the flat-spacetime limit of quantum gravity using the Bekenstein argument in reverse

An insightful argument for a linear relation between the entropy and the area of a black hole was given by Bekenstein using only the energy-momentum dispersion relation, the uncertainty principle, and some properties of classical black holes. Recent analyses within String Theory and Loop Quantum Gravity describe black-hole entropy in terms of a dominant contribution, which indeed depends linearly on the area, and a leading log-area correction. We argue that, by reversing the Bekenstein argument, the log-area correction can provide insight on the energy-momentum dispersion relation and the uncertainty principle of a quantum-gravity theory. As examples we consider the energy-momentum dispersion relations that recently emerged in the Loop Quantum Gravity literature and the Generalized Uncertainty Principle that is expected to hold in String Theory.Comment: 7 pages, LaTex; this essay received an "honorable mention" in the 2004 Essay Competition of the Gravity Research Foundation; submitted to IJMPD on 23 June 2004; published as Int.J.Mod.Phys.D13:2337-2343,200

Comparison of relativity theories with observer-independent scales of both velocity and length/mass

We consider the two most studied proposals of relativity theories with observer-independent scales of both velocity and length/mass: the one discussed by Amelino-Camelia as illustrative example for the original proposal (gr-qc/0012051) of theories with two relativistic invariants, and an alternative more recently proposed by Magueijo and Smolin (hep-th/0112090). We show that these two relativistic theories are much more closely connected than it would appear on the basis of a naive analysis of their original formulations. In particular, in spite of adopting a rather different formal description of the deformed boost generators, they end up assigning the same dependence of momentum on rapidity, which can be described as the core feature of these relativistic theories. We show that this observation can be used to clarify the concepts of particle mass, particle velocity, and energy-momentum-conservation rules in these theories with two relativistic invariants.Comment: 21 pages, LaTex. v2: Andrea Procaccini (contributing some results from hia Laurea thesis) is added to the list of authors and the paper provides further elements of comparison between DSR1 and DSR2, including the observation that both lead to the same formula for the dependence of momentum on rapidit

Daily Regulation of Key Metabolic Pathways in Two Seagrasses Under Natural Light Conditions

The circadian clock is an endogenous time-keeping mechanism that enables organisms to adapt to external environmental cycles. It produces rhythms of plant metabolism and physiology, and interacts with signaling pathways controlling daily and seasonal environmental responses through gene expression regulation. Downstream metabolic outputs, such as photosynthesis and sugar metabolism, besides being affected by the clock, can also contribute to the circadian timing itself. In marine plants, studies of circadian rhythms are still way behind in respect to terrestrial species, which strongly limits the understanding of how they coordinate their physiology and energetic metabolism with environmental signals at sea. Here, we provided a first description of daily timing of key core clock components and clock output pathways in two seagrass species, Cymodocea nodosa and Zostera marina (order Alismatales), co-occurring at the same geographic location, thus exposed to identical natural variations in photoperiod. Large differences were observed between species in the daily timing of accumulation of transcripts related to key metabolic pathways, such as photosynthesis and sucrose synthesis/transport, highlighting the importance of intrinsic biological, and likely ecological attributes of the species in determining the periodicity of functions. The two species exhibited a differential sensitivity to light-to-dark and dark-to-light transition times and could adopt different growth timing based on a differential strategy of resource allocation and mobilization throughout the day, possibly coordinated by the circadian clock. This behavior could potentially derive from divergent evolutionary adaptations of the species to their bio-geographical range of distributions

Beyond head and neck cancer: The relationship between oral microbiota and tumour development in distant organs

An altered oral microbiota has been linked with the development of several oral diseases, such as dental caries, periodontal disease, and oral stomatitis. Moreover, poor oral health has been linked to head and neck cancer, particularly oral cancer. In recent years a growing number of studies indicate that oral microbiota could be involved in the development of primary tumours outside of head and neck region. The aim of this article is to review the recent studies based on high-throughput technology to present evidences of a relationship between oral microbiota and \u201cnon-head and neck tumours.\u201d Oral dysbiosis seem to be more pronounced in patients with tumours of gastrointestinal tract, in particular oesophageal, gastric, pancreatic, and colorectal cancers, paving the way for developing specific oral microbiota test to allow early cancer detection. Regarding other tumour types, the results are promising but highly preliminary and still debated. Currently, there are several factors that limit the generalization of the results, such as the small sample size, the lack of adequate clinical information about patients, the different sequencing techniques used, and biological sample heterogeneity. Although only at the beginning, the analysis of oral microbiota could be the next step in the evolution of cancer therapy and will help clinicians to develop individualised approaches to cancer prevention and treatment

High-Order Corrections to the Entropy and Area of Quantum Black Holes

The celebrated area-entropy formula for black holes has provided the most important clue in the search for the elusive theory of quantum gravity. We explore the possibility that the (linear) area-entropy relation acquires some smaller corrections. Using the Boltzmann-Einstein formula, we rule out the possibility for a power-law correction, and provide severe constraints on the coefficient of a possible log-area correction. We argue that a non-zero logarithmic correction to the area-entropy relation, would also imply a modification of the area-mass relation for quantum black holes.Comment: 3 page

Enzyme replacement therapy with agalsidase beta improves cardiac involvement in Fabry's disease.

Fabry's disease is an X-linked lysosomal storage disease caused by a deficiency of alpha-galactosidase that results in an accumulation of neutral glycosphingolipids throughout the body, including the cardiovascular system. Fabry cardiomyopathy, characterized by progressive severe concentric left ventricular (LV) hypertrophy, is very frequent and is the most important cause of death in affected patients. Enzyme replacement therapy (ERT) allows a specific treatment for this disease, however, there are very few data on the effectiveness of therapy on cardiac involvement. Nine patients with Fabry cardiac disease were studied on basal condition and after 6 and 12 months of treatment with algasidase beta (Fabrazyme). A complete clinical, electrocardiographic and echocardiographic evaluation was performed in all patients. Interpretable Doppler recordings of transmitral flow and pulmonary flow velocity curves were also acquired. At baseline, the patients with Fabry's disease had increased LV septum and posterior wall thickness, normal LV fractional shortening, LV ejection fraction, normal Doppler parameters of mitral inflow but a duration of pulmonary vein flow velocity wave exceeding that of the mitral wave at atrial systole. ERT did not affect heart rate and arterial pressure. LV internal diameters did not change, there was a slight but not significant decrease in the LV posterior wall thickening and a progressive decrease in the interventricular septum thickening (p < 0.025) and in LV mass (p < 0.001) The difference in duration between pulmonary vein flow velocity wave and mitral wave at atrial systole significantly decreased (p < 0.001). These results suggest that ERT in patients with Fabry cardiomyopathy is able to reduce the LV mass and ameliorate the LV stiffness

Sugars dominate the seagrass rhizosphere

Seagrasses are among the most efficient sinks of carbon dioxide on Earth. While carbon sequestration in terrestrial plants is linked to the microorganisms living in their soils, the interactions of seagrasses with their rhizospheres are poorly understood. Here, we show that the seagrass, Posidonia oceanica excretes sugars, mainly sucrose, into its rhizosphere. These sugars accumulate to mu M concentrations-nearly 80 times higher than previously observed in marine environments. This finding is unexpected as sugars are readily consumed by microorganisms. Our experiments indicated that under low oxygen conditions, phenolic compounds from P. oceanica inhibited microbial consumption of sucrose. Analyses of the rhizosphere community revealed that many microbes had the genes for degrading sucrose but these were only expressed by a few taxa that also expressed genes for degrading phenolics. Given that we observed high sucrose concentrations underneath three other species of marine plants, we predict that the presence of plant-produced phenolics under low oxygen conditions allows the accumulation of labile molecules across aquatic rhizospheres. Seagrass meadows are important carbon sinks. Here, the authors show that organic carbon in the form of simple sugars can accumulate at high concentrations in seagrass rhizospheres because plant phenolic compounds inhibit their consumption by microorganisms

Protocol of the Long-term Impact of RAS Inhibition on Cardiorenal Outcomes (LIRICO) randomized trial.

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Dr. Zompo: an online data repository for Zostera marina and Posidonia oceanica ESTs

As ecosystem engineers, seagrasses are angiosperms of paramount ecological importance in shallow shoreline habitats around the globe. Furthermore, the ancestors of independent seagrass lineages have secondarily returned into the sea in separate, independent evolutionary events. Thus, understanding the molecular adaptation of this clade not only makes significant contributions to the field of ecology, but also to principles of parallel evolution as well. With the use of Dr. Zompo, the first interactive seagrass sequence database presented here, new insights into the molecular adaptation of marine environments can be inferred. The database is based on a total of 14 597 ESTs obtained from two seagrass species, Zostera marina and Posidonia oceanica, which have been processed, assembled and comprehensively annotated. Dr. Zompo provides experimentalists with a broad foundation to build experiments and consider challenges associated with the investigation of this class of non-domesticated monocotyledon systems. Our database, based on the Ruby on Rails framework, is rich in features including the retrieval of experimentally determined heat-responsive transcripts, mining for molecular markers (SSRs and SNPs), and weighted key word searches that allow access to annotation gathered on several levels including Pfam domains, GeneOntology and KEGG pathways. Well established plant genome sites such as The Arabidopsis Information Resource (TAIR) and the Rice Genome Annotation Project are interfaced by Dr. Zompo. With this project, we have initialized a valuable resource for plant biologists in general and the seagrass community in particular. The database is expected to grow together with more data to come in the near future, particularly with the recent initiation of the Zostera genome sequencing project

Erratum:corrigendum: transcriptome characterisation and simple sequence repeat marker discovery in the seagrass Posidonia oceanica

Scientific Data 3:160115 doi: 10.1038/sdata.2016.115 (2016); Published 20 December 2016; Updated 14 March 2017 The original version of this Data Descriptor contained a typographical error in the spelling of the author A. Lamontanara, which was incorrectly given as A. Lamontara. This has now been corrected in the PDF and HTML versions of the Data Descriptor.</jats:p