Velocity, energy and helicity of vortex knots and unknots

In this paper we determine the velocity, the energy and estimate writhe and twist helicity contributions of vortex filaments in the shape of torus knots and unknots (toroidal and poloidal coils) in a perfect fluid. Calculations are performed by numerical integration of the Biot-Savart law. Vortex complexity is parametrized by the winding number $w$, given by the ratio of the number of meridian wraps to that of the longitudinal wraps. We find that for $w<1$ vortex knots and toroidal coils move faster and carry more energy than a reference vortex ring of same size and circulation, whereas for $w>1$ knots and poloidal coils have approximately same speed and energy of the reference vortex ring. Helicity is dominated by the writhe contribution. Finally, we confirm the stabilizing effect of the Biot-Savart law for all knots and unknots tested, that are found to be structurally stable over a distance of several diameters. Our results also apply to quantized vortices in superfluid $^4$He.Comment: 17 pages, 8 figures, 2 table

OWidgets: A toolkit to enable smell-based experience design

Interactive technologies are transforming the ways in which people experience, interact and share information. Advances in technology have made it possible to generate real and virtual environments with breath-taking graphics and high-fidelity audio. However, without stimulating the other senses such as touch and smell, and even taste in some cases, such experiences feel hollow and fictitious; they lack realism. One of the main stumbling blocks for progress towards creating truly compelling multisensory experiences is the lack of appropriate tools and guidance for designing beyond audio-visual applications. Here we focus particularly on the sense of smell and how smell-based design can be enabled to create novel user experiences. We present a design toolkit for smell (i.e., OWidgets). The toolkit consists of a graphical user interface and the underlying software framework. The framework uses two main components: a Mapper and Scheduler facilitating the device-independent replication of olfactory experiences. We discuss how our toolkit reduces the complexity of designing with smell and enables a creative exploration based on specific design features. We conclude by reflecting on future directions to extend the toolkit and integrate it into the wider audio-visual ecosystem

Aldosterone status associates with insulin resistance in patients with heart failure-data from the ALOFT study

&lt;b&gt;Background&lt;/b&gt;: Aldosterone plays a key role in the pathophysiology of heart failure. In around 50% of such patients, aldosterone 'escapes' from inhibition by drugs that interrupt the renin-angiotensin axis; such patients have a worse clinical outcome. Insulin resistance is a risk factor in heart failure and cardiovascular disease. The relationship between aldosterone status and insulin sensitivity was investigated in a cohort of heart failure patients. &lt;b&gt;Methods&lt;/b&gt;: 302 patients with New York Heart Association (NYHA) class II-IV heart failure on conventional therapy were randomized in ALiskiren Observation of heart Failure Treatment study (ALOFT), designed to test the safety of a directly acting renin inhibitor. Plasma aldosterone and 24-hour urinary aldosterone excretion as well as fasting insulin and Homeostasis model assessment of insulin resistance (HOMA-IR) were measured. Subjects with aldosterone escape and high urinary aldosterone were identified according to previously accepted definitions. &lt;b&gt;Results&lt;/b&gt;: Twenty per-cent of subjects demonstrated aldosterone escape and 34% had high urinary aldosterone levels. At baseline, there was a positive correlation between fasting insulin and plasma(r=0.22 p&#60;0.01) and urinary aldosterone(r=0.19 p&#60;0.03). Aldosterone escape and high urinary aldosterone subjects both demonstrated higher levels of fasting insulin (p&#60;0.008, p&#60;0.03), HOMA-IR (p&#60;0.06, p&#60;0.03) and insulin-glucose ratios (p&#60;0.006, p&#60;0.06) when compared to low aldosterone counterparts. All associations remained significant when adjusted for potential confounders. &lt;b&gt;Conclusions&lt;/b&gt;: This study demonstrates a novel direct relationship between aldosterone status and insulin resistance in heart failure. This observation merits further study and may identify an additional mechanism that contributes to the adverse clinical outcome associated with aldosterone escape

Characterization of a potassium-stimulated ATPase in membrane fraction isolated from roots of grapevine seedlings

A microsomal fraction possessing Mg2+-dependent and K+-stimulated ATPase activity was extracted by differential centrifugation from roots of grape seedlings (Vitis vinifera L. cv. Verduzzo).Roots yield from grape seeds was stimulated by means of GA3 and further improved by treatments able to control microbial contamination.The biochemical characteristics of ATPase activity were studied and compared with those previously reported for roots produced by grape woody cuttings.The presence of choline-Cl, ethanolamine and glycerol-1-P in addition to BSA, EDTA, PVPP and DTT in the homogenizing medium was obligatory in order to record the K+-stimulated component of activity.The enzyme was activated by Mg2+, further stimulated by monovalent ions and showed strong preference for ATP as the substrate and optimum pH at 6.5 in the presence of both Mg2+ and K+. The effect of different monovalent ions followed a sequence similar to that found in cereal roots preparations, but very different with respect to that recorded for preparations from roots of grape woody cuttings.K+-ATPase activity was inhibited by vanadate and DES whereas molybdate and azide had no or scarce effect . ATPase activity showed a simple Michaelis-Menten saturation with increasing ATP: Mg concentration, and a complex pattern of possible negative cooperativity for K+ stimulation.Microsomes fractionated using sucrose density gradient showed enrichment in plasmalemma vesicles at 1.10-1,15 g ml-1 density.This parameter differentiates this fraction from similar preparations containing plasmalemma ATPase obtained from roots of various annual plants

SERPINB3 delays glomerulonephritis and attenuates the lupus-like disease in lupus murine models by inducing a more tolerogenic immune phenotype

Objective: To explore the effects of SERPINB3 administration in murine lupus models with a focus on lupus-like nephritis. Methods: 40 NZB/W F1 mice were subdivided into 4 groups and intraperitoneally injected with recombinant SERPINB3 (7.5 \u3bcg/0.1 mL or 15 \u3bcg/0.1 mL) or PBS (0.1 mL) before (group 1 and 2) or after (group 3 and 4) the development of proteinuria ( 65100 mg/dl). Two additional mice groups were provided by including 20 MRL/lpr mice which were prophylactically injected with SERPINB3 (10 mice, group 5) or PBS (10 mice, group 6). Time of occurrence and levels of anti-dsDNA and anti-C1q antibodies, proteinuria and serum creatinine, overall- and proteinuria-free survival were assessed in mice followed up to natural death. Histological analysis was performed in kidneys of both lupus models. The Th17:Treg cell ratio was assessed by flow-cytometry in splenocytes of treated and untreated MRL/lpr mice. Statistical analysis was performed using non parametric tests and Kaplan-Meier curves, when indicated. Results: Autoantibody levels and proteinuria were significantly decreased and time of occurrence significantly delayed in SERPINB3-treated mice vs. controls. In agreement with these findings, proteinuria-free and overall survival were significantly improved in SERPINB3-treated groups vs. controls. Histological analysis demonstrated a lower prevalence of severe tubular lesions in kidneys of group 5 vs. group 6. SERPINB3-treated mice showed an overall trend toward a reduced prevalence of severe lesions in both strains. Th17:Treg ratio was significantly decreased in splenocytes of MRL/lpr mice treated with SERPINB3, compared to untreated control mice. Conclusions: SERPINB3 significantly improves disease course and delays the onset of severe glomerulonephritis in lupus-prone mice, possibly inducing a more tolerogenic immune phenotype

The Impact of Model and Rainfall Forcing Errors on Characterizing Soil Moisture Uncertainty in Land Surface Modeling

The contribution of rainfall forcing errors relative to model (structural and parameter) uncertainty in the prediction of soil moisture is investigated by integrating the NASA Catchment Land Surface Model (CLSM), forced with hydro-meteorological data, in the Oklahoma region. Rainfall-forcing uncertainty is introduced using a stochastic error model that generates ensemble rainfall fields from satellite rainfall products. The ensemble satellite rain fields are propagated through CLSM to produce soil moisture ensembles. Errors in CLSM are modeled with two different approaches: either by perturbing model parameters (representing model parameter uncertainty) or by adding randomly generated noise (representing model structure and parameter uncertainty) to the model prognostic variables. Our findings highlight that the method currently used in the NASA GEOS-5 Land Data Assimilation System to perturb CLSM variables poorly describes the uncertainty in the predicted soil moisture, even when combined with rainfall model perturbations. On the other hand, by adding model parameter perturbations to rainfall forcing perturbations, a better characterization of uncertainty in soil moisture simulations is observed. Specifically, an analysis of the rank histograms shows that the most consistent ensemble of soil moisture is obtained by combining rainfall and model parameter perturbations. When rainfall forcing and model prognostic perturbations are added, the rank histogram shows a U-shape at the domain average scale, which corresponds to a lack of variability in the forecast ensemble. The more accurate estimation of the soil moisture prediction uncertainty obtained by combining rainfall and parameter perturbations is encouraging for the application of this approach in ensemble data assimilation systems

Communicating cosmology with multisensory metaphorical experiences

We present a novel approach to communicating abstract concepts in cosmology and astrophysics in a more accessible and inclusive manner. We describe an exhibit aiming at creating an immersive, multisensory metaphorical experience of an otherwise imperceptible physical phenomenon-dark matter. Human-Computer Interaction experts and physicists co-created a multisensory journey through dark matter by exploiting the latest advances in haptic and olfactory technology. We present the concept design of a pilot and a second, improved event, both held at the London Science Museum, including the practical setup of the multisensory dark matter experience, the delivery of sensory stimulation and preliminary insights from users' feedback

Communicating cosmology with multisensory metaphorical experiences

We present a novel approach to communicating abstract concepts in cosmology and astrophysics in a more accessible and inclusive manner. We describe an exhibit aiming at creating an immersive, multisensory metaphorical experience of an otherwise imperceptible physical phenomenon-dark matter. Human-Computer Interaction experts and physicists co-created a multisensory journey through dark matter by exploiting the latest advances in haptic and olfactory technology. We present the concept design of a pilot and a second, improved event, both held at the London Science Museum, including the practical setup of the multisensory dark matter experience, the delivery of sensory stimulation and preliminary insights from users' feedback

The role of temperature and oxygen availability on the distribution of Corbicula largillierti

The invasiveness of Corbicula largillierti has been underestimated, but this bivalve is currently receiving more attention. The first study of the distribution of this species along one of the major basins of central Argentina showed that it was completely absent in the major central reservoir, but was present along its tributary and effluent rivers. Ten years later, this discontinuous distribution has not changed, despite the bivalve's high dispersion capacity. The main environmental differences between the reservoir and the rivers are that the former has finer sediment grain size, higher temperatures, and lower oxygen concentration during summer months. This study aimed to evaluate whether one of these factors could be limiting the distribution of C. largillierti. We assessed the metabolic response and burial behavior (under different grain sizes) of C. largillierti over 8 weeks at 30°C against a control condition at 20°C. We also analyzed the oxygen consumption (vO2) as a function of environmental oxygen concentration (pO2) at 25°C, estimating its metabolic regulation capacity (R). This showed the existence of an environmental oxygen concentration threshold (Pt) that could be an indicative of physiological limiting concentrations that compromise species survival and settlement. After 8 weeks at 30°C, the metabolic rate of individuals of C. largillierti increased and their burial behavior was slightly compromised but mostly for coarser sediments. Concerning environmental oxygen availability, C. largillierti is an oxyconformer with a low R (39.9%), a clear pattern of negative regulation, and a low Pt (48.4% air saturation). The lack of any regulation capacity of C. largillierti under environmental oxygen limitations and the extremely low pO2 at the bottom of the reservoir during summer months may explain its failure to colonize and survive there.Fil: Rodriguez, Florencia Anahi. Universidad Nacional de Córdoba; ArgentinaFil: Reyna, Paola Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; ArgentinaFil: Maggioni, Tamara. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; ArgentinaFil: Gimenez, Diego R.. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; ArgentinaFil: Torre, Luciana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; Argentin

Vortex length, vortex energy and fractal dimension of superfluid turbulence at very low temperature

By assuming a self-similar structure for Kelvin waves along vortex loops with successive smaller scale features, we model the fractal dimension of a superfluid vortex tangle in the zero temperature limit. Our model assumes that at each step the total energy of the vortices is conserved, but the total length can change. We obtain a relation between the fractal dimension and the exponent describing how the vortex energy per unit length changes with the length scale. This relation does not depend on the specific model, and shows that if smaller length scales make a decreasing relative contribution to the energy per unit length of vortex lines, the fractal dimension will be higher than unity. Finally, for the sake of more concrete illustration, we relate the fractal dimension of the tangle to the scaling exponents of amplitude and wavelength of a cascade of Kelvin waves.Comment: 12 pages, 1 figur