Ultra-high energy extragalactic neutrinos interacting with ultra-light dark matter

We show the results and discussions of the study of a possible suppression of the extragalactic neutrino flux during its propagation due to a nonstandard interaction with a candidate field to dark matter. In particular, we show the study of neutrino interaction with an ultra-light scalar field. It is shown that the extragalactic neutrino flux may be suppressed by such an interaction, leading to a mechanism to reduce the ultra-high energy neutrino flux. We calculate both the cases of non-self-conjugate as well as self-conjugate ultra-light dark matter. In the first case, the suppression is independent of the neutrino and dark matter masses. We conclude that care must be taken when explaining limits on the neutrino flux through source acceleration mechanisms only, since there could be other mechanisms, as absorption during propagation, for the reduction of the neutrino flux [1], © Published under licence by IOP Publishing Ltd.

On Non-ideal and Chaotic Energy Harvester Behavior

In this paper, we deal with the research of a proposed mathematical model of energy harvesting, including nonlinearities in the piezoelectric coupling and a non-ideal force of excitation. We showed using numerical simulations to analysis of the dynamic responses that, the power harvested was influenced by the nonlinear vibrations of the structure, as well as by the influence of the non-linearities in the piezoelectric coupling. We concluded through of the numerical results that the limited energy source was interacting with the system. Thus, the increasing of the voltage in DC motor led the system produce a good power response, especially in high-energy orbits in the resonance region, but the Sommerfeld effect occurs in the system and a chaotic behavior was found in the post-resonance region. So the power harvested along the time decreases because occurs loses of energy due the interaction between energy source and structure. Keeping the energy harvested constant over time is essential to make possible the use of energy harvesting systems in real applications. To achieve this objective, we applied a control technique in order to stabilize the chaotic system in a periodic stable orbit. We announced that the results were satisfactory and the control maintained the system in a stable condition. © 2012 Foundation for Scientific Research and Technological Innovation.

D̄N interaction in a color-confining chiral quark model

We investigate the low-energy elastic D̄N interaction using a quark model that confines color and realizes dynamical chiral symmetry breaking. The model is defined by a microscopic Hamiltonian inspired in the QCD Hamiltonian in Coulomb gauge. Constituent quark masses are obtained by solving a gap equation, and baryon and meson bound-state wave functions are obtained using a variational method. We derive a low-energy meson-nucleon potential from a quark-interchange mechanism whose ingredients are the quark-quark and quark-antiquark interactions and baryon and meson wave functions, all derived from the same microscopic Hamiltonian. The model is supplemented with (σ, ρ, ω, a0) single-meson exchanges to describe the long-range part of the interaction. Cross sections and phase shifts are obtained by iterating the quark-interchange plus meson-exchange potentials in a Lippmann-Schwinger equation. Once coupling constants of long-range scalar σ and a0 meson exchanges are adjusted to describe experimental phase shifts of the K+N and K0N reactions, predictions for cross sections and s-wave phase shifts for the D̄0N and D-N reactions are obtained without introducing new parameters. © 2013 American Physical Society.

Interaction between mesenchymal stem cells and Ti-30Ta alloy after surface treatment

In this study, in vitro cytocompatibility was investigated in the Ti-30Ta alloy after two kinds of surfaces treatments: alkaline and biomimetic treatment. Each condition was evaluated by scanning electron microscopy/energy-dispersive X-ray spectroscopy. Cellular adhesion, viability, protein expression, morphology, and differentiation were evaluated with Bone marrow stromal cells (MSCs) to investigate the short and long-term cellular response by fluorescence microscope imaging and colorimetric assays techniques. Two treatments exhibited similar results with respect to total protein content and enzyme activity as compared with alloy without treatment. However, it was observed improved of the biomineralization, bone matrix formation, enzyme activity, and MSCs functionality after biomimetic treatment. These results indicate that the biomimetic surface treatment has a high potential for enhanced osseointegration. © 2013 Wiley Periodicals, Inc.

A non-ideal portal frame energy harvester controlled using a pendulum

A model of energy harvester based on a simple portal frame structure is presented. The system is considered to be non-ideal system (NIS) due to interaction with the energy source, a DC motor with limited power supply and the system structure. The nonlinearities present in the piezoelectric material are considered in the piezoelectric coupling mathematical model. The system is a bi-stable Duffing oscillator presenting a chaotic behavior. Analyzing the average power variation, and bifurcation diagrams, the value of the control variable that optimizes power or average value that stabilizes the chaotic system in the periodic orbit is determined. The control sensitivity is determined to parametric errors in the damping and stiffness parameters of the portal frame. The proposed passive control technique uses a simple pendulum to tuned to the vibration of the structure to improve the energy harvesting. The results show that with the implementation of the control strategy it is possible to eliminate the need for active or semi active control, usually more complex. The control also provides a way to regulate the energy captured to a desired operating frequency. © 2013 EDP Sciences and Springer.

Dynamics of the interaction between body fluid and Ti cp: the influence of surface functionalization in the first stages of osseointegration

INTRODUCTION: Regenerative therapies using biomaterials require accurate information on interactions between the implanted material and the human body. To improve the process of bone regeneration it is necessary to obtain a better understanding of the influence of the surfaces on the early stages of osseointegration. This work aims to investigate the dynamic interaction between simulated body fluid (SBF) and titanium surfaces (Ti cp) immediately after their first contact. METHODS: Ti cp samples were passed through physicochemical treatments after immersion in acid solution, alkaline solution and solutions containing TiO2 and Ca2+, to obtain three different surfaces. These were characterized by electron microscopy and free energy estimates. The evaluation of the interaction with SBF was performed by measuring the dynamic contact angles after contacting the surfaces. RESULTS: The effects of SBF wettability were more significant on surfaces according to high energy estimates. A comparative analysis of the three types of surfaces showed that fluid spreading was greater in samples with greater polar components, indicating that the surface nature influences interactions in the early stages of osseointegration. CONCLUSION: The results indicate the influence of polar interactions in the dynamic wettability of the SBF. It is possible that these interactions can also influence cellular viability on surfaces. Based on these results, new experiments are being designed to improve the presented methodology as a tool for the evaluation of biomaterials without the need for in vivo experiments.

Sugarcane trash management assessed by the interaction of yield with soil properties

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Supplementation based on protein or energy ingredients to beef cattle consuming low-quality cool-season forages: I. Forage disappearance parameters in rumen-fistulated steers and physiological responses in pregnant heifers

Two experiments evaluated the influence of supplement composition on ruminal forage disappearance, performance, and physiological responses of Angus x Hereford cattle consuming a low-quality cool-season forage (8.7% CP and 57% TDN). In Exp. 1, 6 rumen-fistulated steers housed in individual pens were assigned to an incomplete 3 x 2 Latin square design containing 2 periods of 11 d each and the following treatments: 1) supplementation with soybean meal (PROT), 2) supplementation with a mixture of cracked corn, soybean meal, and urea (68:22:10 ratio, DM basis; ENER), or 3) no supplementation (CON). Steers were offered meadow foxtail (Alopecurus pratensis L.) hay for ad libitum consumption. Treatments were provided daily at 0.50 and 0.54% of shrunk BW/steer for PROT and ENER, respectively, to ensure that PROT and ENER intakes were isocaloric and isonitrogenous. No treatment effects were detected on rumen disappearance parameters of forage DM (P >= 0.33) and NDF (P >= 0.66). In Exp. 2, 35 pregnant heifers were ranked by initial BW on d -7 of the study, allocated into 12 feedlot pens (4 pens/treatment), and assigned to the same treatments and forage intake regimen as in Exp. 1 for 19 d. Treatments were fed once daily at 1.77 and 1.92 kg of DM/heifer for PROT and ENER, respectively, to achieve the same treatment intake as percent of initial BW used in Exp. 1 (0.50 and 0.54% for PROT and ENER, respectively). No treatment effects (P = 0.17) were detected on forage DMI. Total DMI was greater (P < 0.01) for PROT and ENER compared with CON and similar between PROT and ENER (P = 0.36). Accordingly, ADG was greater (P = 0.01) for PROT compared with CON, tended to be greater for ENER compared with CON (P = 0.08), and was similar between ENER and PROT (P = 0.28). Heifers receiving PROT and ENER had greater mean concentrations of plasma glucose (P = 0.03), insulin (P <= 0.09), IGF-I (P <= 0.04), and progesterone (P = 0.01) compared to CON, whereas ENER and PROT had similar concentrations of these variables (P >= 0.15). A treatment x hour interaction was detected (P < 0.01) for plasma urea N (PUN), given that PUN concentrations increased after supplementation for ENER and PROT (time effect, P < 0.01) but did not change for CON (time effect, P = 0.62). In conclusion, beef cattle consuming low-quality cool-season forages had similar ruminal forage disappearance and intake, performance, and physiological status if offered supplements based on soybean meal or corn at 0.5% of BW.

Shear viscosity due to Landau damping from the quark-pion interaction

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Crude Glycerin associated with starch or fiber-based energy ingredients at two levels of concentrate for beef cattle

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Missing transverse energy performance of the CMS detector

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Charge effect in the interaction of doxorubicin and derivatives with polydeoxynucleotides

The equilibrium interaction of doxorubicin and its N-acetyl derivative with a series of purine-pyrimidine alternating polydeoxynucleotides has been studied through spectrofluorometry to assess the relevance of the electrostatic contribution to DNA intercalation. The results have shown that: (a) the suppression of the positive charge on the aminosugar has: (I) a profound negative effect on the free energy of intercalation, as expected, and (II) a negligible influence on the base specificity, which supports the notion of an essentially electrostatic effect of N-acetylation on intercalation; (b) a reasonably good accord with the demands of a polyelectrolytic model, due to Friedman and Manning, is found.

Dark energy as a kinematic effect

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Energy sources in the supplementation of beef cattle grazing Brachiaria brizantha cv. Xaraés

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Accurate ab initio potential energy surfaces for the (3)A '' and (3)A ' electronic states of the O(P-3) plus HBr system

In this work, we report the construction of potential energy surfaces for the (3)A '' and (3)A' states of the system O(P-3) + HBr. These surfaces are based on extensive ab initio calculations employing the MRCI+Q/CBS+SO level of theory. The complete basis set energies were estimated from extrapolation of MRCI+Q/aug-cc-VnZ(-PP) (n = Q, 5) results and corrections due to spin-orbit effects obtained at the CASSCF/aug-cc-pVTZ(-PP) level of theory. These energies, calculated over a region of the configuration space relevant to the study of the reaction O(P-3) + HBr -> OH + Br, were used to generate functions based on the many-body expansion. The three-body potentials were interpolated using the reproducing kernel Hilbert space method. The resulting surface for the (3)A '' electronic state contains van der Waals minima on the entrance and exit channels and a transition state 6.55 kcal/mol higher than the reactants. This barrier height was then scaled to reproduce the value of 5.01 kcal/mol, which was estimated from coupled cluster benchmark calculations performed to include high-order and core-valence correlation, as well as scalar relativistic effects. The (3)A' surface was also scaled, based on the fact that in the collinear saddle point geometry these two electronic states are degenerate. The vibrationally adiabatic barrier heights are 3.44 kcal/mol for the (3)A '' and 4.16 kcal/mol for the (3)A' state. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4705428]