Effects of forcing in three dimensional turbulent flows

We present the results of a numerical investigation of three-dimensional homogeneous and isotropic turbulence, stirred by a random forcing with a power law spectrum, $E_f(k)\sim k^{3-y}$. Numerical simulations are performed at different resolutions up to $512^3$. We show that at varying the spectrum slope $y$, small-scale turbulent fluctuations change from a {\it forcing independent} to a {\it forcing dominated} statistics. We argue that the critical value separating the two behaviours, in three dimensions, is $y_c=4$. When the statistics is forcing dominated, for $y<y_c$, we find dimensional scaling, i.e. intermittency is vanishingly small. On the other hand, for $y>y_c$, we find the same anomalous scaling measured in flows forced only at large scales. We connect these results with the issue of {\it universality} in turbulent flows.Comment: 4 pages, 4 figure

Oral Feeding Competences of Healthy Preterm Infants: A Review

Background. With increasing sophistication and technology, survival rates hugely improved among preterm infants admitted to the neonatal intensive care unit. Nutrition and feeding remain a challenge and preterm infants are at high risk of encountering oral feeding difficulties. Objective. To determine what facts may impact on oral feeding readiness and competence and which kind of interventions should enhance oral feeding performance in preterm infants. Search Strategy. MEDILINE database was explored and articles relevant to this topic were collected starting from 2009 up to 2011. Main Results. Increasingly robust alertness prior to and during feeding does positively impact the infant's feeding Skills. The review found that oral and non-oral sensorimotor interventions, provided singly or in combination, shortened the transition time to independent oral feeding in preterm infants and that preterm infants who received a combined oral and sensorimotor intervention demonstrated more advanced nutritive sucking, suck-swallow and swallow-respiration coordination than those who received an oral or sensorimotor intervention singly

Dynamic features of the selective pressure on the human immunodeficiency virus type 1 (HIV-1) gp120 CD4-binding site in a group of long term non progressor (LTNP) subjects.

Abstract The characteristics of intra-host human immunodeficiency virus type 1 (HIV-1) env evolution were evaluated in untreated HIV-1-infected subjects with different patterns of disease progression, including 2 normal progressor [NP], and 5 Long term non-progressor [LTNP] patients. High-resolution phylogenetic analysis of the C2-C5 env gene sequences of the replicating HIV-1 was performed in sequential samples collected over a 3–5 year period; overall, 301 HIV-1 genomic RNA sequences were amplified from plasma samples, cloned, sequenced and analyzed. Firstly, the evolutionary rate was calculated separately in the 3 codon positions. In all LTNPs, the 3rd codon mutation rate was equal or even lower than that observed at the 1st and 2nd positions (p = 0.016), thus suggesting strong ongoing positive selection. A Bayesian approach and a maximum-likelihood (ML) method were used to estimate the rate of virus evolution within each subject and to detect positively selected sites respectively. A great number of N-linked glycosylation sites under positive selection were identified in both NP and LTNP subjects. Viral sequences from 4 of the 5 LTNPs showed extensive positive selective pressure on the CD4-binding site (CD4bs). In addition, localized pressure in the area of the IgG-b12 epitope, a broad neutralizing human monoclonal antibody targeting the CD4bs, was documented in one LTNP subject, using a graphic colour grade 3-dimensional visualization. Overall, the data shown here documenting high selective pressure on the HIV-1 CD4bs of a group of LTNP subjects offers important insights for planning novel strategies for the immune control of HIV-1 infection.</p

Blood Flow Energy Identifies Coronary Lesions Culprit of Future Myocardial Infarction.

The present study establishes a link between blood flow energy transformations in coronary atherosclerotic lesions and clinical outcomes. The predictive capacity for future myocardial infarction (MI) was compared with that of established quantitative coronary angiography (QCA)-derived predictors. Angiography-based computational fluid dynamics (CFD) simulations were performed on 80 human coronary lesions culprit of MI within 5 years and 108 non-culprit lesions for future MI. Blood flow energy transformations were assessed in the converging flow segment of the lesion as ratios of kinetic and rotational energy values (KER and RER, respectively) at the QCA-identified minimum lumen area and proximal lesion sections. The anatomical and functional lesion severity were evaluated with QCA to derive percentage area stenosis (%AS), vessel fractional flow reserve (vFFR), and translesional vFFR (ΔvFFR). Wall shear stress profiles were investigated in terms of topological shear variation index (TSVI). KER and RER predicted MI at 5 years (AUC = 0.73, 95% CI 0.65-0.80, and AUC = 0.76, 95% CI 0.70-0.83, respectively; p &lt; 0.0001 for both). The predictive capacity for future MI of KER and RER was significantly stronger than vFFR (p = 0.0391 and p = 0.0045, respectively). RER predictive capacity was significantly stronger than %AS and ΔvFFR (p = 0.0041 and p = 0.0059, respectively). The predictive capacity for future MI of KER and RER did not differ significantly from TSVI. Blood flow kinetic and rotational energy transformations were significant predictors for MI at 5 years (p &lt; 0.0001). The findings of this study support the hypothesis of a biomechanical contribution to the process of plaque destabilization/rupture leading to MI

Morbidity and mortality of sickle cell disease patients is unaffected by splenectomy: evidence from three decades of follow-up in a high-income setting

Sickle cell disease (SCD) is a globally widespread hereditary red cell disorder characterized by the production of pathological hemoglobin S (HbS).1 Patients with SCD include homozygous subjects for HbS (SS) and compound heterozygotes with HbS/HbC (SC) or HbS/β+/0-thalassemia (Sβ0/β+). In Italy, SCD is endemic with HbS/β+/0-thalassemia being prevalent in areas of southern Italy. In the last two decades, the number of SCD patients across Italy has increased due to migration from sub-Saharan Africa and th

Influence of land use on the hydrobiogeochemistry of the Camanducaia and Jaguari watersheds, Brazil.

Two medium-sized watersheds of the Piracicaba river basin, the Camanducaia and Jaguari subbasins,are being studied to evaluate the effects of land use change on the basin?s hydrobiogeochemistry. The Jaguari basin is an important provider the Cantareira reservoir system that supplies around six million inhabitants of the Metropolitan Region of São Paulo, Brazil. A one-year hydrological study began on January 2015 to monitor some water quality parameters such as pH, electric conductivity (EC), dissolved oxygen (DO), dissolved organic and inorganic carbon (DOC and DIC), nitrate (NO ), ammonium (NH ) and total nitrogen (TN). For that purpose we established 19 sampling stations along the Camanducaia (8 stations) and Jaguari (11 stations) river channels; two stations at their main tributaries Mosquito and Camanducaia Mineiro, respectively; and another two stations at small streams in headwater areas of the Jaguari and Camanducaia watersheds. Preliminary results show that DOC concentrations are correlated DIC (r=0.81 at Jaguari; r=0.70 at Camanducaia; p <0.05). We observe that DOC tends to increase by multiples of 2.5 and 3.5 times from forested headwater areas to the most downstream stations of Jaguari and Camanducaia, respectively. Regarding DIC these multiples are 4.4 and 1.9 times greater. The four most downstream stations at Jaguari show urban area effects with higher DIC monthly values ranging from 28.7 to 33 mg L . Also DIC correlated with EC values (means around 160 ?S) at two of these stations. We expect that at the end of this monitoring year results will show stronger relations between hydrobiogeochemical parameters and land use change

Study of fast-ion-driven toroidal Alfvén eigenmodes impacting on the global confinement in TCV L-mode plasmas

Following recent observations of unstable Toroidal Alfvén Eigenmodes (TAEs) in a counter-current Neutral Beam Injection (NBI) scenario developed in TCV, an in-depth analysis of the impact of such modes on the global confinement and performance is carried out. The study shows experimental evidence of non-degradation of ion thermal confinement despite the increasing of auxiliary power. During such an improved confinement period, Toroidal Alfvén Eigenmodes (TAEs) driven by fast ions generated through Neutral Beam Injection (NBI) are found unstable. Together with the TAEs, various instabilities associated with the injection of the fast neutrals are observed by multiple diagnostics, and a first characterization is given. Nonlinear wave-wave couplings are also detected through multi-mode analysis, revealing a complex picture of the stability dynamics of the TCV scenario at hand. The measurements provided by a short-pulse reflectometer corroborate the identification and radial localization of the instabilities. A preliminary, but not conclusive, analysis of the impact of TAEs on the amplitude of the electron density fluctuations is carried out. Local flux-tube gyrokinetic simulations show that the dominant underlying instabilities in the absence of fast ions are Trapped Electron Modes (TEM), and that these modes are effectively suppressed by zonal flows. Attempts to simulate the simultaneous presence of fast-ion driven TAEs and TEM turbulence show that elongated streamers develop up to the full radial extent of the flux-tube domain, thereby invalidating the local assumption and indicating that a global approach is mandatory in these TCV plasmas

Clinical and morphological characteristics of head-facial haemangiomas

BACKGROUND: Haemangiomas of the head or face are a frequent vascular pathology, consisting in an embryonic dysplasia that involves the cranial-facial vascular network. Haemangiomas show clinical, morphological, developmental and structural changes during their course. METHODS: The clinical characteristics of head-facial haemagiomas were studied in 28 individuals (9 males and 19 females) admitted in our Hospital. Sixteen of these patients(n = 16) underwent surgery for the removal of the haemangiomas. All the removed tissues were transferred in experimental laboratories for the staining of microanatomical details, somatic and visceral nerve fibres, adrenergic and catecholaminergic nerve fibres. Beta-adrenergic receptors were died with a fluorescent method. All results were submitted to the quantitative analysis of images and statistical evaluation of the data. RESULTS: The morphological results revealed numerous micro-anatomical characteristics of the haemangiomatous vessels. The somatic and visceral nerve fibres were poor and located exclusively in the adventitial layer. There was a marked decrease of adrenergic nerve fibres in the haemangiomatous vessels. The fluorescence of catecholaminergic nerve fibres and the overall area of fluorescent structures were also decreased in haemangiomatous vessels. Beta adrenergic receptors are strongly decreased in haemangiomatous vessels. The morphometrical analysis of images and statistical evaluation of the data confirmed all our experimental results. CONCLUSION: The catecholaminergic innervation of the human haemangiomatous vessels comprises nerve fibres containing the main catecholaminergic neurotransmitters that are sympathetic in nature. These neurotransmitters are closely related to beta-adrenergic receptors. The sympathetic nervous system plays a key role in the control of the vascular bed flow and vascular motility in both normal and haemangiomatous vessels