Interplay between curvature and Planck-scale effects in astrophysics and cosmology

Several recent studies have considered the implications for astrophysics and cosmology of some possible nonclassical properties of spacetime at the Planck scale. The new effects, such as a Planck-scale-modified energy-momentum (dispersion) relation, are often inferred from the analysis of some quantum versions of Minkowski spacetime, and therefore the relevant estimates depend heavily on the assumption that there could not be significant interplay between Planck-scale and curvature effects. We here scrutinize this assumption, using as guidance a quantum version of de Sitter spacetime with known Inonu-Wigner contraction to a quantum Minkowski spacetime. And we show that, contrary to common (but unsupported) beliefs, the interplay between Planck-scale and curvature effects can be significant. Within our illustrative example, in the Minkowski limit the quantum-geometry deformation parameter is indeed given by the Planck scale, while in the de Sitter picture the parameter of quantization of geometry depends both on the Planck scale and the curvature scalar. For the much-studied case of Planck-scale effects that intervene in the observation of gamma-ray bursts we can estimate the implications of "quantum spacetime curvature" within robust simplifying assumptions. For cosmology at the present stage of the development of the relevant mathematics one cannot go beyond semiheuristic reasoning, and we here propose a candidate approximate description of a quantum FRW geometry, obtained by patching together pieces (with different spacetime curvature) of our quantum de Sitter. This semiheuristic picture, in spite of its limitations, provides rather robust evidence that in the early Universe the interplay between Planck-scale and curvature effects could have been particularly significant.Comment: 26 pages

Usefulness of transesophageal echocardiography in the assessment of aortic dissection

The acute dissection of the ascending aorta requires prompt and reliable diagnosis to reduce the high risk of mortality; in addition, prognosis is influenced by longterm complications. The aim of this article is to discuss transesophageal echocardiography (TEE) and (1) its diagnostic accuracy in the presurgical evaluation of patients, (2) its role in reducing time of diagnosis and surgery, and (3) its ability to reduce hospital mortality. TEE has also been tested as a screening method in the postsurgical follow-up of these patients. The retrospective investigation concerns a sample of 80 cases of acute dissection of the aorta, submitted for surgical intervention from April 1986 to February 1999. TEE has allowed a precise estimation of aortic diameters and optimal visualization of intimal flap and tear entry with a fine distinction between true and false lumen. A direct comparison of the results of TEE and of transthoracic echocardiography has demonstrated that some elements (visualization of flap and diameters in descending aorta, sites of entry and reentry, direction of let trough intimal tears, phasic intimal flap movement, diastolic collapse of flap on the valvular plane, false lumen thrombosis, coronary involvement, intramural hematoma, and aortic fissuration) were identified only by TEE, whereas other additional diagnostic elements (cardiac tamponade, aortic valve insufficiency, left ventricular function) show a similar pattern of significance. Routine employment of this method has confirmed a reduction of hospitalization time (about 1.5 hours of waiting time), and hospital mortality has changed from 42.8% to 17.3%. In the follow-up of patients operated on for aortic dissection, fundamental information may be obtained from TEE (assessment of the progression of thrombosis in the false lumen with its complete obliteration and modifications in aortic diameter with a consequent, possible worsening of aortic valve insufficiency). In conclusion, our study demonstrated that TEE may provide fast and efficient detection of acute aortic dissection. In the postsurgical follow-up, TEE has confirmed detection of major complications that can influence long-term prognosis and may be proposed as a method with easy access-one that is repeatable and inexpensive for the screening of aortic dissection surgical patients. (C) 2000 by Excerpta Medica, Inc

QT Indexes in Cirrhotic Patients: Relationship with Clinical Variables and Potential Diagnostic Predictive Value.

BACKGROUND AND AIMS: A wide spectrum of cardiovascular changes characterizes cirrhosis, ranging from subclinical alterations to hyperkinetic syndrome. We looked for ECG markers of ventricular repolarization in a population of patients with cirrhosis in comparison to patients without cirrhosis and we investigated the relationship between these and other clinical and laboratory variables. METHODS: In 149 patients with cirrhosis and 152 controls, we measured QT maximum interval (QTmax), QT corrected interval (QTc), QT minimum interval (QTmin), QT dispersion (QTdisp), QT peak and T peak-to-end (TpTe). RESULTS: In subjects with cirrhosis, in comparison with controls, we observed a higher mean QTmax, mean QTc, mean QTmin, mean QTdisp and mean TpTe. At Cox regression analysis, diastolic blood pressure and beta-blocker treatment were significantly associated with mean QTmax, hypertension with mean QTmin and mean QTc, diastolic blood pressure, beta-blockers and ACE-inhibitors/ARBs with QT disp, and beta-blockers with TpTe. Analysis of ROC curves showed a significant area under curve towards cirrhosis diagnosis, respectively, for a cut-off value of >400 msec of QTmax, >360 msec of QTmin, >450 msec of QTc, >105 msec of TpTe and >55 msec of QTdisp

TOpic: rare and special cases, the real "Strange cases"

Introduction: The bladder hernia represents approximately 1-3% of all inguinal hernias, where patients aged more than 50 years have a higher incidence (10%). Many factors contribute to the development of a bladder hernia, including the presence of a urinary outlet obstruction causing chronic bladder distention, the loss of bladder tone, pericystitis, the perivesical bladder fat protrusion and the obesity

Rapidly rotating second-generation progenitors for the blue hook stars of {\omega} Cen

Horizontal Branch stars belong to an advanced stage in the evolution of the oldest stellar galactic population, occurring either as field halo stars or grouped in globular clusters. The discovery of multiple populations in these clusters, that were previously believed to have single populations gave rise to the currently accepted theory that the hottest horizontal branch members (the blue hook stars, which had late helium-core flash ignition, followed by deep mixing) are the progeny of a helium-rich "second generation" of stars. It is not known why such a supposedly rare event (a late flash followed by mixing) is so common that the blue hook of {\omega} Cen contains \sim 30% of horizontal branch stars 10 , or why the blue hook luminosity range in this massive cluster cannot be reproduced by models. Here we report that the presence of helium core masses up to \sim 0.04 solar masses larger than the core mass resulting from evolution is required to solve the luminosity range problem. We model this by taking into account the dispersion in rotation rates achieved by the progenitors, whose premain sequence accretion disc suffered an early disruption in the dense environment of the cluster's central regions where second-generation stars form. Rotation may also account for frequent late-flash-mixing events in massive globular clusters.Comment: 44 pages, 8 figures, 2 tables in Nature, online june 22, 201

Campagna di ricerca in mare: Sezione G – MEDITS 2012. Sub-area Geografica (GSA) 16 – Stretto di Sicilia

La campagna scientifica Medits, nell’ambito del Programma nazionale Italiano per la raccolta dei dati alieutici (Reg. CE n°199/2008 e n°665/2008), ha l’obiettivo generale di valutare la distribuzione, l’abbondanza e la composizione per taglia delle specie oggetto di pesca presenti nei mari Italiani. L’Istituto di ricerche per l’Ambiente Marino Costiero (IAMC), sede di Mazara del Vallo, del Consiglio nazionale delle Ricerche (CNR), effettua campagne di ricerca in mare nella GSA 16 (FAO, 2001) dello Stretto di Sicilia, tramite rete a strascico (trawl survey), sin dalla primavera del 1985, con l’obiettivo generale di studiare l’abbondanza ed i cicli vitali delle risorse demersali e di stimarne lo stato di sfruttamento

Prognostic relevance of serum beta2 microglobulin in patients with follicular lymphoma treated with anthracycline-containing regimens. A GISL study.

Background and ObjectivesAlthough serum b2 microglobulin (b2M) is an easy parameter to measure, and overexpressedin a large number of lymphoproliferative diseases, its prognostic value hasbeen largely underestimated. The present study examined the influence of b2M levelson overall survival (OS) of patients with follicular lymphoma (FL).Design and MethodsThe prognostic role of b2M was evaluated in 236 patients with FL identified from thedatabases of the Gruppo Italiano per lo Studio dei Linfomi (GISL) and treated withanthracycline-based regimens from 1993 to 2003.ResultsElevated serum b2M levels were found in 82 patients (35%). According to multivariatelogistic regression analysis, elevated b2M levels were associated with elevatedlactate dehydrogenase (LDH) (p=0.021), age (p=0.029), and number of involvednodal areas (p<0.001). The percentage of elevated b2M levels increased progressivelywith increasing FLIPI scores (17%, 38%, and 63% in the low-, intermediate-, andhigh-risk groups, respectively). Five-year OS was 61% (95% CI, 47-73%) and 89% (95%CI, 82-93%) for patients with elevated vs normal b2M levels respectively (p<0.001).Cox regression analysis showed that b2M level had an independent and stable prognosticvalue (HR=3.0; 95%CI, 1.6-5.7). In a multivariate analysis the impact of b2Mlevel on survival was independent of FLIPI score, with a HR of 2.94 (95% CI, 1.54-5.62).Interpretation and ConclusionsOur results demonstrate that in patients treated in the pre-rituximab era, b2M levelwas an independent prognostic marker in addition to FLIPI score. We thus suggestthat b2M be routinely assessed and tested in future prognostic studies of FL patientstreated with combination chemotherapy and anti-CD20 agents

The M 4 Core Project with HST - III. Search for variable stars in the primary field

We present the results of a photometric search for variable stars in the core of the Galactic globular cluster Messier 4 (M 4). The input data are a large and unprecedented set of deep Hubble Space Telescope WFC3 images (large programme GO-12911; 120 orbits allocated), primarily aimed at probing binaries with massive companions by detecting their astrometric wobbles. Though these data were not optimized to carry out a time-resolved photometric survey, their exquisite precision, spatial resolution and dynamic range enabled us to firmly detect 38 variable stars, of which 20 were previously unpublished. They include 19 clustermember eclipsing binaries (confirming the large binary fraction ofM4), RR Lyrae and objects with known X-ray counterparts. We improved and revised the parameters of some among published variables

Central Adrenal Insufficiency Is Rare in Adults With Prader-Willi Syndrome

CONTEXT: Prader-Willi syndrome (PWS) is associated with several hypothalamic-pituitary hormone deficiencies. There is no agreement on the prevalence of central adrenal insufficiency (CAI) in adults with PWS. In some countries, it is general practice to prescribe stress-dose hydrocortisone during physical or psychological stress in patients with PWS. Side effects of frequent hydrocortisone use are weight gain, osteoporosis, diabetes mellitus, and hypertension-already major problems in adults with PWS. However, undertreatment of CAI can cause significant morbidity-or even mortality. OBJECTIVE: To prevent both over- and undertreatment with hydrocortisone, we assessed the prevalence of CAI in a large international cohort of adults with PWS. As the synacthen test shows variable results in PWS, we only use the metyrapone test (MTP) and insulin tolerance test (ITT). DESIGN: Metyrapone test or ITT in adults with PWS (N = 82) and review of medical files for symptoms of hypocortisolism related to surgery (N = 645). SETTING: Outpatient clinic. PATIENTS OR OTHER PARTICIPANTS: Eighty-two adults with genetically confirmed PWS. MAIN OUTCOME MEASURE: For MTP, 11-deoxycortisol > 230 nmol/L was considered sufficient. For ITT, cortisol > 500 nmol/L (Dutch, French, and Swedish patients) or > 450 nmol/L (British patients) was considered sufficient. RESULTS: Central adrenal insufficiency was excluded in 81 of 82 patients. Among the 645 patients whose medical files were reviewed, 200 had undergone surgery without perioperative hydrocortisone treatment. None of them had displayed any features of hypocortisolism. CONCLUSIONS: Central adrenal insufficiency is rare (1.2%) in adults with PWS. Based on these results, we recommend against routinely prescribing hydrocortisone stress-doses in adults with PWS

Hip viscosupplementation under ultra-sound guidance riduces NSAID consumption in symptomatic hip osteoarthritis patients in a long follow-up. Data from Italian registry.

Introduction: Non-steroidal anti-inflammatory drugs (NSAIDs) consumption is strictly related to a high gastrointestinal and cardiovascular mortality and morbidity rate. Osteoarthritis Research Society International (OARSI) recommendations in patients with symptomatic hip or knee OA stated that NSAIDs should be used at the lowest effective dose but their long-term use should be avoided if possible. OARSI guidelines for the treatment of the hip OA include the use of viscosupplementation, which aims to restore physiological and Theological features of the synovial fluid. Objective: Aim of this multicentric, open and retrospective study is to investigate if NSAID consumption may be reduced by the use of ultrasound-guided intra-articular injection of several hyaluronic acid (HA) products in hip joint administered in patients affected by symptomatic hip OA. Materials and Methods: Patients affected by mono or bilateral symptomatic hip OA according to American Rheumatology Association (ARA) criteria, radiological OA graded II-IV (Kellgren and Lawrence) entered the study and were administered with ultrasound-guided intra-articular injection of hyaluronic acid products. As a primary endpoint, consumption of NSAIDs was evaluated by recording the number of days a month (range 0-30) the patient had used NSAID during the previous month, reported at each visit during the 24 months follow-up period. Secondary endpoints included further analysis for subgroups of patients categorized for Lequesne index score, Kellgren-Lawrence score, pain visual analogue scale (VAS) score, ultrasound pattern, age, hyaluronic acid used. Results: 2343 patients entered the study. Regarding primary endpoint, the consumption of NSAIDs was reduced of 48.2% at the third month when compared with baseline values. This sparing effect increased at 12th and 24th month with a reduction respectively of 50% and 61% in comparison to baseline values. These differences were statistically significant. Conclusions: These data point out that intraarticular hyaluronan preparations provide OA pain relief and reduce NSAIDs consumption in a large cohort of patients for a long period of follow-up. Multiple courses of viscosupplementation (vs) are required to maintain low dose of NSAID consumption over time. NSAIDs consumption is strictly related to an high gastrointestinal and cardiovascular mortality and morbidity rate, instead HA intra-articular treatment is well tolerated and is associated with a low incidence of adverse effects. For these reasons further studies evaluating cost-effectiveness and cost-utility of VS in the management of hip OA are required