Static Hopfions in the extended Skyrme-Faddeev model

We construct static soliton solutions with non-zero Hopf topological charges to a theory which is an extension of the Skyrme-Faddeev model by the addition of a further quartic term in derivatives. We use an axially symmetric ansatz based on toroidal coordinates, and solve the resulting two coupled non-linear partial differential equations in two variables by a successive over-relaxation (SOR) method. We construct numerical solutions with Hopf charge up to four, and calculate their analytical behavior in some limiting cases. The solutions present an interesting behavior under the changes of a special combination of the coupling constants of the quartic terms. Their energies and sizes tend to zero as that combination approaches a particular special value. We calculate the equivalent of the Vakulenko and Kapitanskii energy bound for the theory and find that it vanishes at that same special value of the coupling constants. In addition, the model presents an integrable sector with an infinite number of local conserved currents which apparently are not related to symmetries of the action. In the intersection of those two special sectors the theory possesses exact vortex solutions (static and time dependent) which were constructed in a previous paper by one of the authors. It is believed that such model describes some aspects of the low energy limit of the pure SU(2) Yang-Mills theory, and our results may be important in identifying important structures in that strong coupling regime.Comment: 22 pages, 42 figures, minor correction

Chemical and bioactive characterization of blueberry bioresidues

Blueberry production has increased exponentially in recent decades due to its known high nutritional characteristics, and bioresidues originating from its culture have also increased. It is critical to limit its buildup. One strategy for directing these residues is to turn them into high-value products while investigating their potential bioactivity. The goal of this study was to produce bioactive extracts from blueberry aerial parts using environmentally friendly methods. Different extracts, such as infusion, maceration, and decoction, were considered, as well as emerging extraction technologies, such as ultrasound-assisted extraction, in which different conditions (potency, temperature, and solvent type) were tested to achieve optimal extraction conditions (high yields and purity). The obtained extracts were studied regarding their chemical profile through phenolic compound´s identification and quantification by HPLC-DAD-MS.info:eu-repo/semantics/publishedVersio

Formation of complex Langmuir and Langmuir-Blodgett films of water soluble rosebengal

This communication reports the formation of complex Langmuir monolayer at the air-water interface by charge transfer types of interaction with the water soluble N- cetyl N, N, N trimethyl ammonium bromide (CTAB) molecules doped with rosebengal (RB), with the stearic acid (SA) molecules of a preformed SA Langmuir monolayer. The reaction kinetics of the formation of RB-CTAB-SA complex monolayer was monitored by observing the increase in surface pressure with time while the barrier was kept fixed. Completion of interaction kinetics was confirmed by FTIR study. This complex Langmuir films at the air-water interface was transferred onto solid substrates at a desired surface pressure to form multilayered Langmuir-Blodgett films. Spectroscopic characterizations reveal some molecular level interactions as well as formation of microcrystalline aggregates depending upon the molar ratios of CTAB and RB within the complex LB films. Presence of two types of species in the complex LB films was confirmed by fluorescence spectroscopy.Comment: 13 pages, figures

Contact-induced spin polarization in carbon nanotubes

Motivated by the possibility of combining spintronics with molecular structures, we investigate the conditions for the appearance of spin-polarization in low-dimensional tubular systems by contacting them to a magnetic substrate. We derive a set of general expressions describing the charge transfer between the tube and the substrate and the relative energy costs. The mean-field solution of the general expressions provides an insightful formula for the induced spin-polarization. Using a tight-binding model for the electronic structure we are able to estimate the magnitude and the stability of the induced moment. This indicates that a significant magnetic moment in carbon nanotubes can be observed.Comment: To appear in Phys. Rev. B (2003

Impact of the pulling rate on the redox state and magnetic domains of Fe-Si-O glass ceramic processed by LFZ method

This work studies the effect of the pulling rate, varying from 100 to 400 mm/h, on the redox state, structure and magnetic properties of iron oxide bearing silica glasses processed by laser floating zone (LFZ) method. XRD analysis revealed that the maximum crystallinity is obtained in the fibre grown at the lowest pulling rate. A detailed Raman analysis demonstrated that the global content of Fe2+ increases with pulling rate, while the growth under a lower pulling rate promotes the α-Fe2O3 crystallization. Atomic/magnetic force microscopy provided further evidence of phase-separated iron oxide crystallites formation with a high Fe2+/Ftotal ratio as the pulling rate increases. The magnetic measurements performed over a wide temperature range showed that the highest magnetization is found in the fibre grown at the highest pulling rate. A strong correlation between structural-topographical features and the magnetic characteristics of the glass fibres is substantiated.publishe

Effect of replacing wheat bran with spineless cactus plus urea in sugarcane-based diets for sheep

In times of drought, the availability of feed is reduced, and the use of concentrate ingredients, such as wheat bran, becomes costly for animal production. Thus, the use of spineless cactus emerges as a potential solution to the shortage of feed and water during prolonged drought periods. The objective of this study was to evaluate the effects of replacing wheat bran with spineless cactus plus urea (0%, 25%, 50%, 75%, and 100%) in sugarcane-based diets for sheep on nutrient intake, feeding behaviour, nitrogen balance and microbial protein synthesis. Five male Santa Ines sheep with average initial bodyweight of 34.0 ± 3.6 kg were used in a 5 × 5 Latin square. The maximum intakes of dry matter (DM) (1414 g/day), organic matter (OM) (1281 g/day), crude protein (CP) (204 g/day), neutral detergent fibre corrected for ash and protein (NDFap) (425 g/day), and total digestible nutrients (TDN) (890 g/day) were estimated with replacement levels of 80.2%, 75.3%, 88.6%, 50.5%, and 79.3% respectively. Feeding behaviour was not altered by replacing wheat bran with spineless cactus plus urea. Nitrogen retention increased by 0.10 g/day, while plasmatic urea nitrogen increased by 0.20 mg/day for every 1% level of replacement. The maximum production of microbial nitrogen (15.9 g/day) and microbial protein synthesis (99.4 g/day) were estimated with replacement levels of 45.8 and 45.7%, respectively. It is concluded that up to 80% wheat bran could be replaced with spineless cactus plus urea in sugarcane-based diets for sheep.Keywords: Alternative feed, drought, feeding behaviour, intake, microbial protei

Avaliação do tecido adiposo subcutâneo e visceral abdominal por tomografia computorizada e antropometria e a sua relação com a Síndrome Metabólica

[resumo][abstract

Layered double hydroxide based active corrosion protective sealing of plasma electrolytic oxidation/sol-gel composite coating on AA2024

This work reports a novel approach for growing layered double hydroxide (LDH) films on any plasma electrolytic oxidation (PEO) coated AA2024 independently of the nature of the PEO coating. The specific PEO coating chosen to carry out this work is considered to be not suitable for direct LDH growth because of phase composition and morphological features. In this paper, we describe a new methodology that consists of covering the PEO coating with a thin layer of aluminum oxide based xerogel as the source of aluminate ions for subsequent in-situ LDH growth. X-ray diffraction (XRD) and scanning electron microscope (SEM) images showed a successful formation of LDHs on the surface. An improvement in terms of active corrosion protection was also demonstrated by electrochemical impedance spectroscopy (EIS) and scanning vibrating electrode technique (SVET).publishe

Post-harvest quality of fresh-marketed tomatoes as a function of harvest periods

Losses on tomato business chain start at harvest, a two-months period. At the beginning of the harvest, fruits concentrate at the basal part of the plant, then in the middle, and finally at the top, and undergo changes in diameter and maturity indexes as harvest progresses. The aim of this work was to evaluate the impact of handling at three different periods: (I) 15 days, (II) 30 days, and (III) 45 days after the beginning of harvest. Tomatoes were ordinarily grown and harvested in to bamboo baskets, and transferred to plastics boxes. Fruits were classified according to ripening stage and diameter, and evaluated for mechanical damage and external defects caused by harvesting procedures. The time required for the harvest operation was measured; damage to fruits (%) and weight loss (%), caused either in the field and/or during the harvesting process, were taken into consideration and related to the final quality of fruit after storage for 21 days. The same methodology was used all through the production and harvest cycle. The highest % fruit damage occurred during period II, a longer harvest time than the other two periods. Fruits not submitted to handling showed lower weight loss than handled fruits. Fruits harvested in period II and stored for 21 days showed higher losses due to mechanical injury

Persistent spin splitting of a two-dimensional electron gas in tilted magnetic fields

By varying the orientation of the applied magnetic field with respect to the normal of a two-dimensional electron gas, the chemical potential and the specific heat reveal persistent spin splitting in all field ranges. The corresponding shape of the thermodynamic quantities distinguishes whether the Rashba spin-orbit interaction RSOI, the Zeeman term or both dominate the splitting. The interplay of the tilting of the magnetic field and RSOI resulted to an amplified splitting in weak fields. The effects of changing the RSOI strength and the Landau level broadening are also investigated.Comment: 10 pages, 5 figure