N-body dynamics on closed surfaces : the axioms of mechanics

D.G.D. gratefully acknowledges support for this research from CNPq (Conselho Nacional de Desenvolvimento Cientifico e Tecnologico ) and FINEP (Inovação e Pesquisa) in Brazil, and from the UK Engineering and Physical Sciences Research Council (grant no. EP/H001794/1)A major challenge for our understanding of the mathematical basis of particle dynamics is the formulation of N-body and N-vortex dynamics on Riemann surfaces. In this paper, we show how the two problems are, in fact, closely related when considering the role played by the intrinsic geometry of the surface. This enables a straightforward deduction of the dynamics of point masses, using recently derived results for point vortices on general closed differentiable surfaces M endowed with a metric g. We find, generally, that Kepler's Laws do not hold. What is more, even Newton's First Law (the law of inertia) fails on closed surfaces with variable curvature (e.g. the ellipsoid).PostprintPeer reviewe

A pilot study on the e-kayak system: A wireless DAQ suited for performance analysis in flatwater sprint kayaks

Nowadays, in modern elite sport, the identification of the best training strategies which are useful in obtaining improvements during competitions requires an accurate measure of the physiologic and biomechanical parameters that affect performance. The goal of this pilot study was to investigate the capabilities of the e-Kayak system, a multichannel digital acquisition system specifically tailored for flatwater sprint kayaking application. e-Kayak allows the synchronous measure of all the parameters involved in kayak propulsion, both dynamic (including forces acting on the paddle and footrest) and kinematic (including stroke frequency, displacement, velocity, acceleration, roll, yaw, and pitch of the boat). After a detailed description of the system, we investigate its capability in supporting coaches to evaluate the performance of elite athletes\u2019 trough-specific measurements. This approach allows for a better understanding of the paddler\u2019s motion and the relevant effects on kayak behavior. The system allows the coach to carry out a wide study of kayak propulsion highlighting, and, at the same time, the occurrences of specific technical flaws in the paddling technique. In order to evaluate the correctness of the measurement results acquired in this pilot study, these results were compared with others which are available in the literature and which were obtained from subjects with similar characteristics

Deformation of geometry and bifurcation of vortex rings

We construct a smooth family of Hamiltonian systems, together with a family of group symmetries and momentum maps, for the dynamics of point vortices on surfaces parametrized by the curvature of the surface. Equivariant bifurcations in this family are characterized, whence the stability of the Thomson heptagon is deduced without recourse to the Birkhoff normal form, which has hitherto been a necessary tool.Comment: 26 page

Effects of Dietary Zn/Se and α-Tocopherol Supplementation on Metabolic Milieu, Haemogram and Semen Traits of Breeding Stallions

Trace element status and metabolic milieu are sometimes overlooked in common veterinary clinical practice across animal species. The evaluation of requirements of trace elements, in fact, may be useful to prevent the perturbation of tissue-specific metabolic impair. In particular, essential trace elements in the diet play key roles within sub-cellular metabolic patterns with macro effects at the systemic level, like blood cell stability and semen quality. This effect was studied in breeding stallions, in which semen quality and haemogram are important for reproduction. A case-control feeding trial involved 40 stallions (age: 8–21 years; body weight, BW: 510–531 kg) of one stud centre, allotted to two experimental groups (n = 20 control, CON vs. n = 20 supplemented, SUPPL100), following a matched-pairs approach based on age. Supplemented stallions (SUPPL100) received a mixed mineral and vitamin supplement of Zn/Se and α-tocopherol (α-TOH) (100 g/day stallion) to compound feed, fed as control diet to horses of the control group (CON). Horses resulted deficient in circulating α-TOH and Zn at the start, though clinically healthy. After supplementation, different plasmatic levels of α-TOH, Zn and Se were found between groups. Circulating basophils (BASO) and mean cell haemoglobin concentration (MCHC) were affected by the dietary treatment (p < 0.05). Plasmatic Se affected monocyte count, haematocrit, mean cell volume and mean cell haemoglobin concentration. Semen traits were not affected by the dietary treatment per se, except for mobile/progressive sperm cells (%) of stallions aged > 13 years marginal circulating levels of α-TOH (p = 0.04). Ameliorating the micromineral status showed to improve the haemogram of stallions in view of circulating levels of Cu. Semen quality appeared to be strongly dependent on animal effects

Albarella future – zero carbon emission

Climate warming is setting requirements on research also in the agronomic and forest fields. The soil and vegetation are available as carbon sinks. Ecosystems under high exploitation lost part of their carbon. It is possible to recover this carbon from the air with natural processes and to return it to the land. Besides, global warming requires a change in mentality that moves into the replacement of fossil fuels with other energy sources. In this perspective, the island of Albarella, with its environment and economic activities, represents an attractive miniature model of the planet Earth. For this design, we estimated (Vensim simulation) the emissions and storage of CO2 equivalent of the whole island. Then, with the idea of acting on natural ecosystems to make them more active in carbon storage, we analyzed two vegetation series from the forest to the sea, one located in the nearby natural reserve of Porto Caleri, and one on the island of Albarella. The investigation concerns the soil carbon storage and the quality and quantity of populations of arthropods, bacteria, and fungi as well. The biodiversity of artificial environments resulted in higher than that of natural habitats, opening a debate. Acting in different ways on the substitution of fuels, we obtained scenarios with decreasing emissions, from consumerist without substitution of fuels, realistic with 15% of replacement by solar energy, and sustainable with zero use of fossil energy and all the island electricity produced through photovoltaic panels

Prepuberal stimulation of 5-HT7-R by LP-211 in a rat model of hyper-activity and attention-deficit: permanent effects on attention, brain amino acids and synaptic markers in the fronto-striatal interface

The cross-talk at the prefronto-striatal interface involves excitatory amino acids, different receptors, transducers and modulators. We investigated long-term effects of a prepuberal, subchronic 5-HT7-R agonist (LP-211) on adult behaviour, amino acids and synaptic markers in a model for Attention-Deficit/Hyperactivity Disorder (ADHD). Naples High Excitability rats (NHE) and their Random Bred controls (NRB) were daily treated with LP-211 in the 5th and 6th postnatal week. One month after treatment, these rats were tested for indices of activity, non selective (NSA), selective spatial attention (SSA) and emotionality. The quantity of L-Glutamate (L-Glu), L-Aspartate (L-Asp) and L-Leucine (L-Leu), dopamine transporter (DAT), NMDAR1 subunit and CAMKIIα, were assessed in prefrontal cortex (PFC), dorsal (DS) and ventral striatum (VS), for their role in synaptic transmission, neural plasticity and information processing. Prepuberal LP-211 (at lower dose) reduced horizontal activity and (at higher dose) increased SSA, only for NHE but not in NRB rats. Prepuberal LP-211 increased, in NHE rats, L-Glu in the PFC and L-Asp in the VS (at 0.250 mg/kg dose), whereas (at 0.125 mg/kg dose) it decreased L-Glu and L-Asp in the DS. The L-Glu was decreased, at 0.125 mg/kg, only in the VS of NRB rats. The DAT levels were decreased with the 0.125 mg/kg dose (in the PFC), and increased with the 0.250 mg/kg dose (in the VS), significantly for NHE rats. The basal NMDAR1 level was higher in the PFC of NHE than NRB rats; LP-211 treatment (at 0.125 mg/kg dose) decreased NMDAR1 in the VS of NRB rats. This study represents a starting point about the impact of developmental 5-HT7-R activation on neuro-physiology of attentive processes, executive functions and their neural substrates

Ketogal: A Derivative Ketorolac Molecule with Minor Ulcerogenic and Renal Toxicity

Ketorolac is a powerful non-steroidal anti-inflammatory drug (NSAID), with a great analgesic activity, present on the Italian market since 1991. Despite the excellent therapeutic activity, the chronic use of ketorolac has long been limited owing to the high incidence of gastrointestinal and kidney side events. In our previous study, we demonstrated that ketorolac–galactose conjugate (ketogal), synthesized and tested in a single-dose study, was able to reduce ulcerogenicity, while preserving the high pharmacological efficacy of its parent drug. In this paper, in order to verify the suitability of this compound, for repeated administration, ex vivo experiments on naïve mice were performed. Mice were treated for 5 or 7 days with the highest doses of two drugs (ketorolac 10 mg/kg and ketogal 16.3 mg/kg), and the expression of both gastric COX-1 and PGsyn was evaluated. Results showed that oral ketorolac treatment significantly reduced both enzymes; surprisingly, oral treatment with ketogal did not produce significant variation in the expression of the two constitutive enzymes. Moreover, histological experiments on stomach and kidneys clearly indicated that repeated administration of ketogal induced lower toxicity than ketorolac. At same time, in vivo results clearly showed that both ketorolac and ketogal had a similar therapeutic activity in a model of inflammation and in pain perception. These effects were accompanied by the reduction of enzyme expression such as COX-2 and iNOS, and by the modulation of levels of nuclear NF-kB and cytosolic IkB-a in the inflamed paws. These very encouraging results demonstrate for the first time that ketogal could represent a valid and novel therapeutic alternative to the ketorolac and might pave the way for clinical studies

Jets, Stickiness and Anomalous Transport

Dynamical and statistical properties of the vortex and passive particle advection in chaotic flows generated by four and sixteen point vortices are investigated. General transport properties of these flows are found anomalous and exhibit a superdiffusive behavior with typical second moment exponent (\mu \sim 1.75). The origin of this anomaly is traced back to the presence of coherent structures within the flow, the vortex cores and the region far from where vortices are located. In the vicinity of these regions stickiness is observed and the motion of tracers is quasi-ballistic. The chaotic nature of the underlying flow dictates the choice for thorough analysis of transport properties. Passive tracer motion is analyzed by measuring the mutual relative evolution of two nearby tracers. Some tracers travel in each other vicinity for relatively large times. This is related to an hidden order for the tracers which we call jets. Jets are localized and found in sticky regions. Their structure is analyzed and found to be formed of a nested sets of jets within jets. The analysis of the jet trapping time statistics shows a quantitative agreement with the observed transport exponent.Comment: 17 pages, 17 figure

Rilievo 3D della Tensa Capitolina mediante metodologia laser scanning

Nell\u2019ambito del rilievo tridimensionale di oggetti di interesse archeologico, artistico, architettonico ed ingegneristico, \ue8 sempre pi\uf9 frequente l\u2019utilizzo di metodologie laser scanning e fotogrammetriche terrestri1. Tali metodologie consentono di acquisire elevate quantit\ue0 di dati in tempi brevi, ad alta risoluzione e con precisioni elevate; le informazioni ottenute sono utilizzate per la ricostruzione virtuale della geometria e della morfologia delle superfici degli oggetti di interesse, per scopi di archivio e conservazione, analisi strutturale, studi dettagliati, navigazione e fruizione virtuale ecc\u20262. La metodologia laser scanning si avvale di strumenti hardware dotati di una sorgente laser, il cosiddetto \u201cmezzo attivo\u201d. Gli strumenti che vengono utilizzati possono essere suddivisi in tre differenti classi: laser scanner a tempo di volo, a differenza di fase e a triangolazione. Nel primo caso, i punti vengono acquisiti misurando il \u201ctempo di volo\u201d (Time Of Flight \u2013 TOF) di un impulso laser che percorre la distanza strumento-oggetto in andata e in ritorno; in quelli a differenza di fase vengono confrontate le fasi di un determinato segnale in partenza ed in arrivo, in quelli a triangolazione vengono misurati gli angoli in uscita ed in entrata tra il raggio laser e lo strumento. In ogni caso, vengono utilizzati specchi rotanti che, mediante piccole rotazioni, permettono di direzionare il raggio laser verso le superfici dell\u2019oggetto e orientarlo nello spazio con micro spostamenti per acquisire grandi quantit\ue0 di punti ad alta densit\ue0. Questi strumenti sono detti a scansione in quanto proiettano sulla superficie esposta dell\u2019oggetto un segnale laser puntuale o a striscia, orizzontale o verticale. Il passaggio del segnale sulla superficie dell\u2019oggetto definisce una griglia regolare con un passo di campionamento scelto in funzione dello scopo del rilievo e che corrisponde alla risoluzione della misura; questa griglia risulta strettamente dipendente dal tipo di laser scanner, dall\u2019ottica utilizzata e dalla distanza strumento-oggetto, i cui nodi rappresentano i punti che vengono poi acquisiti sulla superficie dell\u2019oggetto. Di ognuno di questi vengono calcolate le coordinate X, Y, Z rispetto ad un sistema di riferimento la cui origine \ue8 posta all\u2019interno dello strumento, in corrispondenza del centro di emissione del raggio laser: l\u2019insieme dei punti acquisiti viene definito \u201cnuvola di punti\u201d. Generalmente risulta per\uf2 pi\uf9 semplice poter lavorare con superfici continue: le nuvole di punti nella fase di post-processamento vengono convertite in superfici dette mesh. L\u2019operazione di meshing, infatti, realizzata con strumenti software dedicati, costruisce tali superfici a partire dall\u2019interconnessione tra i punti acquisiti creando cos\uec una rete di poligoni irregolari, normalmente triangoli, da cui l\u2019acronimo TIN (Triangulated Irregular Net). In questo modo \ue8 possibile procedere con le successive fasi di costruzione di un modello virtuale dell\u2019oggetto rilevato ed ottenere il Modello Digitale delle Superfici (Digital Surface Model \u2013 DSM