Magnetization reversal process and nonlinear magneto-impedance in Cu/NiFe and Nb/NiFe composite wires

The magnetization reversal of Cu/NiFe and Nb/NiFe composite wires carrying AC current is studied. The frequency spectrum of a voltage induced in a pick-up coil wound around the wire is analyzed. The frequency spectrum is shown to consist of even harmonics within a wide range of AC current amplitudes and longitudinal DC magnetic fields. The strong dependencies of the harmonic amplitudes on the DC field are found. The results obtained may be of importance for the design of weak magnetic field sensors.Comment: 8 pages, 4 figures, publishe

Current distribution and giant magnetoimpedance in composite wires with helical magnetic anisotropy

The giant magnetoimpedance effect in composite wires consising of a non-magnetic inner core and soft magnetic shell is studied theoretically. It is assumed that the magnetic shell has a helical anisotropy. The current and field distributions in the composite wire are found by means of a simultaneous solution of Maxwell equations and the Landau-Lifshitz equation. The expressions for the diagonal and off-diagonal impedance are obtained for low and high frequencies. The dependences of the impedance on the anisotropy axis angle and the shell thickness are analyzed. Maximum field sensitivity is shown to correspond to the case of the circular anisotropy in the magnetic shell. It is demonstrated that the optimum shell thickness to obtain maximum impedance ratio is equal to the effective skin depth in the mahnetic material.Comment: 23 pages, 7 figure

Prevention of HIV and other sexually transmitted infections by geofencing and contextualized messages with a gamified APP, UBESAFE : Design and creation study

Advances in the development of information and communication technologies have facilitated social and sexual interrelationships, thanks to the websites and apps created to this end. However, these resources can also encourage sexual contacts without appropriate preventive measures in relation to HIV and other sexually transmitted infections (STIs). How can users be helped to benefit from the advantages of these apps while keeping in mind those preventive measures? This study aimed to prevent STIs by helping users to remember preventive measures in the risky situations. We have used the design and creation methodology and have developed a software system. This system has two parts: an Android operating system app with emphasis on ubiquitous computing and gamification as well as a server with a webpage. First, a functional test with 5 men who have sex with men (MSM) allowed us to test the app with end users. In addition, a feasibility test with 4 MSM for a month allowed us to try the UBESAFE system with all its functionalities. The main output is a system called UBESAFE that is addressed to MSM. The system has two main parts: (1) an app that sends preventive contextualized messages to users when they use a contact app or when they are near a point where sexual contacts are likely and (2) a server part that was managed by the public health agency of Barcelona (ASPB), which preserves the quality and pertinence of messages and places and offers instant help to users. To increase users' adherence, UBESAFE uses a gamified system to engage users in the creation of preventive messages. Users increased the initial pool of messages by more than 100% (34/30) and created more than 56% (9/16) of places (named hot zones). The system helped MSM who used it to become conscious about HIV and other STIs. The system also helped the ASPB to stay in contact with MSM and to detect behaviors that could benefit from preventive measures. All functions were performed in a nonintrusive manner because users used the app privately. Furthermore, the system has shown how important it is to make users a part of the creation process as well as to develop apps that work by themselves and thus become useful to the users

Phase nucleation in curved space

Theoretical Physic

Epitaxially strained [001]-(PbTiO3_3)1_1(PbZrO3_3)1_1 superlattice and PbTiO3_3 from first principles

The effect of layer-by-layer heterostructuring and epitaxial strain on lattice instabilities and related ferroelectric properties is investigated from first principles for the [001]-(PbTiO$_3$)$_1$(PbZrO$_3$)$_1$ superlattice and pure PbTiO$_3$ on a cubic substrate. The results for the superlattice show an enhancement of the stability of the monoclinic r-phase with respect to pure PbTiO$_3$. Analysis of the lattice instabilities of the relaxed centrosymmetric reference structure computed within density functional perturbation theory suggests that this results from the presence of two unstable zone-center modes, one confined in the PbTiO$_3$ layer and one in the PbZrO$_3$ layer, which produce in-plane and normal components of the polarization, respectively. The zero-temperature dielectric response is computed and shown to be enhanced not only near the phase boundaries, but throughout the r-phase. Analysis of the analogous calculation for pure PbTiO$_3$ is consistent with this interpretation, and suggests useful approaches to engineering the dielectric properties of artificially structured perovskite oxides.Comment: 8 pages, 5 figure

Behavioral responses of Diaphorina citri to host plant volatiles in multiple-choice olfactometers are affected in interpretable ways by effects of background colors and airflows

[EN] In several phytophagous hemipterans, behavior appears to be mediated by both visual and chemical cues. For the Asian citrus psyllid (ACP)Diaphorina citri(Hemiptera: Liviidae), olfactometric assays are generally difficult to interpret owing to the low proportion of individuals responding to odors (similar to 30-40%), which compromises the efficiency and reliability of the results of behavioral tests. In the present study, the ACP behavioral response to emitted odors from sweet orange (Citrus sinensisL. Osbeck) flushes in a 4-arm olfactometer using different colors (four white-, two white- and two yellow- on opposite sides, or four yellow-colored fields), and the role of the airflow in the concentration of volatile organic compounds (VOCs) were assessed at two airflows [0.4 and 0.1 L/min (LPM)]. Exposure to 'Pera' sweet orange or clean air in treatments with four yellow-colored-fields increased the response rate of ACP females to the odor sources compared with exposure to 'Pera' sweet orange or clean air in treatments with four white-colored-fields, independently of the odor source and airflow tested. For the assays using two white- and two yellow-colored fields on opposite sides and 0.4 or 0.1 LPM airflow, the residence time of ACP females to odors ('Pera' sweet orange or clean air) was similar or higher in treatments using yellow- than those using white-colored fields. For both assays (VOCs and olfactometric behavioral parameters), the reduction in airflow from 0.4 to 0.1 LPM greatly changed the airborne concentration and ACP behavior. Quantitative chemical analyses revelead that the concentration of most compounds emitted by 'Pera' sweet orange flushes for the headspace using 0.1 LPM airflow were greater than the concentrations measured using 0.4 LPM airflow. Therefore, this treatment design provides an useful tool to assess the ACP behavioral response to the odors from citrus plants, and it can also help in the discrimination of dose-response screenings for VOCs or conspecific insects.Financial support was provided by Sao Paulo Research Foundation (FAPESP) 2015/07011-3 and 2017/21460-0. The authors thank Dr. Aquidauana Miqueloto Zanardi for her help in measuring the color spaces of the white and yellow reflective papers used to change the device color.Volpe, H.; Zanardi, O.; Magnani, R.; Luvizotto, R.; Esperança, V.; De Freitas, R.; Delfino, J.... (2020). Behavioral responses of Diaphorina citri to host plant volatiles in multiple-choice olfactometers are affected in interpretable ways by effects of background colors and airflows. PLoS ONE. 15(7):1-17. https://doi.org/10.1371/journal.pone.0235630S117157Grafton-Cardwell, E. E., Stelinski, L. L., & Stansly, P. A. (2013). Biology and Management of Asian Citrus Psyllid, Vector of the Huanglongbing Pathogens. Annual Review of Entomology, 58(1), 413-432. doi:10.1146/annurev-ento-120811-153542Tiwari, S., Mann, R. S., Rogers, M. E., & Stelinski, L. L. (2011). Insecticide resistance in field populations of Asian citrus psyllid in Florida. Pest Management Science, 67(10), 1258-1268. doi:10.1002/ps.2181Zanardi, O. Z., Bordini, G. P., Franco, A. A., de Morais, M. R., & Yamamoto, P. T. (2018). Spraying pyrethroid and neonicotinoid insecticides can induce outbreaks of Panonychus citri (Trombidiformes: Tetranychidae) in citrus groves. Experimental and Applied Acarology, 76(3), 339-354. doi:10.1007/s10493-018-0316-1Stockton, D. G., Martini, X., Patt, J. M., & Stelinski, L. L. (2016). The Influence of Learning on Host Plant Preference in a Significant Phytopathogen Vector, Diaphorina citri. PLOS ONE, 11(3), e0149815. doi:10.1371/journal.pone.0149815Knolhoff, L. M., & Heckel, D. G. (2014). Behavioral Assays for Studies of Host Plant Choice and Adaptation in Herbivorous Insects. Annual Review of Entomology, 59(1), 263-278. doi:10.1146/annurev-ento-011613-161945Döring, T. F., & Chittka, L. (2007). Visual ecology of aphids—a critical review on the role of colours in host finding. Arthropod-Plant Interactions, 1(1), 3-16. doi:10.1007/s11829-006-9000-1NISSINEN, A., KRISTOFFERSEN, L., & ANDERBRANT, O. (2008). Physiological state of female and light intensity affect the host-plant selection of carrot psyllid, Trioza apicalis (Hemiptera: Triozidae). European Journal of Entomology, 105(2), 227-232. doi:10.14411/eje.2008.032MOUND, L. A. (1962). STUDIES ON THE OLFACTION AND COLOUR SENSITIVITY OF BEMISIA TABACI (GENN.) (HOMOPTERA, ALEYRODIDAE). Entomologia Experimentalis et Applicata, 5(2), 99-104. doi:10.1111/j.1570-7458.1962.tb00571.xAntignus, Y., Mor, N., Ben Joseph, R., Lapidot, M., & Cohen, S. (1996). Ultraviolet-Absorbing Plastic Sheets Protect Crops from Insect Pests and from Virus Diseases Vectored by Insects. Environmental Entomology, 25(5), 919-924. doi:10.1093/ee/25.5.919Hall, D. G., Sétamou, M., & Mizell, R. F. (2010). A comparison of sticky traps for monitoring Asian citrus psyllid (Diaphorina citri Kuwayama). Crop Protection, 29(11), 1341-1346. doi:10.1016/j.cropro.2010.06.003Godfrey, K. E., Galindo, C., Patt, J. M., & Luque-Williams, M. (2013). Evaluation of Color and Scent Attractants Used to Trap and Detect Asian Ctirus Psyllid (Hemiptera: Liviidae) in Urban Environments. Florida Entomologist, 96(4), 1406-1416. doi:10.1653/024.096.0420Sétamou, M., Sanchez, A., Saldaña, R. R., Patt, J. M., & Summy, R. (2014). Visual Responses of Adult Asian Citrus Psyllid (Hemiptera: Liviidae) to Colored Sticky Traps on Citrus Trees. Journal of Insect Behavior, 27(4), 540-553. doi:10.1007/s10905-014-9448-2Miranda, M. P., Dos Santos, F. L., Felippe, M. R., Moreno, A., & Fereres, A. (2015). Effect of UV-Blocking Plastic Films on Take-Off and Host Plant Finding Ability of Diaphorina citri (Hemiptera: Liviidae). Journal of Economic Entomology, 108(1), 245-251. doi:10.1093/jee/tou036Paris, T. M., Croxton, S. D., Stansly, P. A., & Allan, S. A. (2015). Temporal response and attraction ofDiaphorina citrito visual stimuli. Entomologia Experimentalis et Applicata, 155(2), 137-147. doi:10.1111/eea.12294Patt, J. M., & Sétamou, M. (2010). Responses of the Asian Citrus Psyllid to Volatiles Emitted by the Flushing Shoots of Its Rutaceous Host Plants. Environmental Entomology, 39(2), 618-624. doi:10.1603/en09216Amorós, M. E., Pereira das Neves, V., Rivas, F., Buenahora, J., Martini, X., Stelinski, L. L., & Rossini, C. (2018). Response of Diaphorina citri (Hemiptera: Liviidae) to volatiles characteristic of preferred citrus hosts. Arthropod-Plant Interactions, 13(3), 367-374. doi:10.1007/s11829-018-9651-8George, J., Shi, Q., Stelinski, L. L., Stover, E., & Lapointe, S. L. (2019). Host Selection, Oviposition and Feeding by a Phytopathogen Vector, Diaphorina citri (Hemiptera: Liviidae), Modulated by Plant Exposure to Formic Acid. Frontiers in Ecology and Evolution, 7. doi:10.3389/fevo.2019.00078Pettersson, J. (1970). An Aphid Sex Attractant. Insect Systematics & Evolution, 1(1), 63-73. doi:10.1163/187631270x00357VET, L. E. M., LENTEREN, J. C. V., HEYMANS, M., & MEELIS, E. (1983). An airflow olfactometer for measuring olfactory responses of hymenopterous parasitoids and other small insects. Physiological Entomology, 8(1), 97-106. doi:10.1111/j.1365-3032.1983.tb00338.xWenninger, E. J., Stelinski, L. L., & Hall, D. G. (2009). Roles of Olfactory Cues, Visual Cues, and Mating Status in Orientation of Diaphorina citri Kuwayama (Hemiptera: Psyllidae) to Four Different Host Plants. Environmental Entomology, 38(1), 225-234. doi:10.1603/022.038.0128Onagbola, E. O., Rouseff, R. L., Smoot, J. M., & Stelinski, L. L. (2010). Guava leaf volatiles and dimethyl disulphide inhibit response of Diaphorina citri Kuwayama to host plant volatiles. Journal of Applied Entomology, 135(6), 404-414. doi:10.1111/j.1439-0418.2010.01565.xAlquézar, B., Volpe, H. X. L., Magnani, R. F., de Miranda, M. P., Santos, M. A., Wulff, N. A., … Peña, L. (2017). β-caryophyllene emitted from a transgenic Arabidopsis or chemical dispenser repels Diaphorina citri, vector of Candidatus Liberibacters. Scientific Reports, 7(1). doi:10.1038/s41598-017-06119-wTomaseto, A. F., Miranda, M. P., Moral, R. A., de Lara, I. A. R., Fereres, A., & Lopes, J. R. S. (2017). Environmental conditions for Diaphorina citri Kuwayama (Hemiptera: Liviidae) take-off. Journal of Applied Entomology, 142(1-2), 104-113. doi:10.1111/jen.12418Wenninger, E. J., & Hall, D. G. (2007). Daily Timing of Mating and Age at Reproductive Maturity in Diaphorina citri (Hemiptera: Psyllidae). Florida Entomologist, 90(4), 715-722. doi:10.1653/0015-4040(2007)90[715:dtomaa]2.0.co;2Shapiro, S. S., & Wilk, M. B. (1965). An Analysis of Variance Test for Normality (Complete Samples). Biometrika, 52(3/4), 591. doi:10.2307/2333709Nelder, J. A., & Wedderburn, R. W. M. (1972). Generalized Linear Models. Journal of the Royal Statistical Society. Series A (General), 135(3), 370. doi:10.2307/2344614Wilcoxon, F. (1945). Individual Comparisons by Ranking Methods. Biometrics Bulletin, 1(6), 80. doi:10.2307/3001968Patt, J. M., Meikle, W. G., Mafra-Neto, A., Sétamou, M., Mangan, R., Yang, C., … Adamczyk, J. J. (2011). Multimodal Cues Drive Host-Plant Assessment in Asian Citrus Psyllid (Diaphorina citri). Environmental Entomology, 40(6), 1494-1502. doi:10.1603/en11149Todd, J. W., Kays, S. J., & Kays, S. E. (1977). A precision low-flow-rate air delivery system for use with olfactometers. Journal of Chemical Ecology, 3(5), 519-525. doi:10.1007/bf00989073Bruce, T. J. A., Wadhams, L. J., & Woodcock, C. M. (2005). Insect host location: a volatile situation. Trends in Plant Science, 10(6), 269-274. doi:10.1016/j.tplants.2005.04.003Bruce, T. J. A., & Pickett, J. A. (2011). Perception of plant volatile blends by herbivorous insects – Finding the right mix. Phytochemistry, 72(13), 1605-1611. doi:10.1016/j.phytochem.2011.04.01

Temperatuurgevoeligheid van Guzmania en Vriesea na de bloei-inductie

In de winter van 2003-2004 is – onder begeleiding van enthousiaste begeleidingscommissie onderzoek (BCO) van de landelijke LTO Bromeliacommissie - een teeltproef uitgevoerd waarbij de invloed van de ruimtetemperatuur (16, 20, of 24°C) in verschillende perioden (1e, 2e of 3e maand) na de bloeibehandeling op het bloeiresultaat en de teeltduur van Guzmania en Vriesea onderzocht is. Doel hierbij was de mogelijkheden tot energiebesparing gedurende een koude periode te onderzoeken, bij voorbeeld door een lagere temperatuur later in de teelt door een hogere teelttemperatuur te compenseren

Influence Of Spin Reorientation On Magnetocaloric Effect In Nd Al2: A Microscopic Model

We report a theoretical investigation about the influence of the spin reorientation from easy magnetic direction 001 to the applied magnetic field direction 111 on the magnetocaloric properties of Nd Al2. This compound was fully investigated using a model Hamiltonian which includes the Zeeman-exchange interactions and the crystalline electrical field, which are responsible for the magnetic anisotropy. All theoretical results were obtained using the proper model parameters for Nd Al2, found in the literature. The existence of a minimum in magnetic entropy change below the phase transition was predicted and ascribed to the strong jump on the spin reorientation. © 2006 The American Physical Society.745Tishin, A.M., Spichkin, Y.I., (2003) The Magnetocaloric Effect and Its Applications, , Institute of Physics, BristolPecharsky, V.K., Gschneidner Jr., K.A., (1997) Phys. Rev. Lett., 78, p. 4494. , PRLTAO 0031-9007 10.1103/PhysRevLett.78.4494Tegus, O., Brück, E., Buschow, K.H.J., De Boer, F.R., (2002) Nature, 415, p. 150. , NATUAS 0028-0836 10.1038/415150AWada, H., Tanabe, Y., (2001) Appl. Phys. Lett., 79, p. 3302. , APPLAB 0003-6951Wada, H., Morikawa, T., Taniguchi, K., Shibata, T., Yamada, Y., Akishige, Y., (2003) Physica B, 328, p. 114. , PHYBE3 0921-4526 10.1016/S0921-4526(02)01822-7Hu, F., Shen, B., Sun, J., Cheng, Z., Rao, G., Zhang, X., (2001) Appl. Phys. Lett., 78, p. 3675. , APPLAB 0003-6951Fujita, A., Fujieda, S., Hasegawa, Y., Fukamichi, K., (2003) Phys. Rev. B, 67, p. 104416. , PRBMDO 0163-1829 10.1103/PhysRevB.67.104416Brown, G.V., (1976) J. Appl. Phys., 47, p. 3673. , JAPIAU 0021-8979 10.1063/1.323176Von Ranke, P.J., De Oliveira, N.A., Gama, S., (2004) J. Magn. Magn. Mater., 277, p. 78. , JMMMDC 0304-8853 10.1016/j.jmmm.2003.10.013Von Ranke, P.J., De Oliveira, N.A., Gama, S., (2004) Phys. Lett. a, 320, p. 302. , PYLAAG 0375-9601 10.1016/j.physleta.2003.10.067Von Ranke, P.J., De Campos, A., Caron, L., Coelho, A.A., Gama, S., De Oliveira, N.A., (2004) Phys. Rev. B, 70, p. 094410. , PRBMDO 0163-1829 10.1103/PhysRevB.70.094410Gama, S., Coelho, A.A., De Campos, A., Carvalho, A.M., Gandra, F.C.G., Von Ranke, P., De Oliveira, N.A., (2004) Phys. Rev. Lett., 93, p. 237202. , PRLTAO 0031-9007 10.1103/PhysRevLett.93.237202Von Ranke, P.J., De Oliveira, N.A., Mello, C., Carvalho, A.M., Gama, S., (2005) Phys. Rev. B, 71, p. 054410. , PRBMDO 0163-1829 10.1103/PhysRevB.71.054410Von Ranke, P.J., Gama, S., Coelho, A.A., De Campos, A., Carvalho, A.M., Gandra, F.C.G., De Oliveira, N.A., (2006) Phys. Rev. B, 73, p. 014415. , PRBMDO 0163-1829 10.1103/PhysRevB.73.014415Von Ranke, P.J., Pecharsky, V.K., Gschneidner, K.A., Korte, B.J., (1998) Phys. Rev. B, 58, p. 14436. , PRBMDO 0163-1829 10.1103/PhysRevB.58.14436Von Ranke, P.J., Mota, M.A., Grangeia, D.F., Carvalho, A.M., Gandra, F.C.G., Coelho, A.A., Caldas, A., Gama, S., (2004) Phys. Rev. B, 70, p. 134428. , PRBMDO 0163-1829 10.1103/PhysRevB.70.134428Lima, A.L., Tsokol, A.O., Gschneidner Jr., K.A., Pecharsky, V.K., Lograsso, T.A., Schlagel, D.L., (2005) Phys. Rev. B, 72, p. 024403. , PRBMDO 0163-1829 10.1103/PhysRevB.72.024403Von Ranke, P.J., De Oliveira, I.G., Guimaraes, A.P., Da Silva, X.A., (2000) Phys. Rev. B, 61, p. 447. , PRBMDO 0163-1829 10.1103/PhysRevB.61.447Lea, K.R., Leask, M.J.M., Wolf, W.P., (1962) J. Phys. Chem. Solids, 33, p. 1381. , JPCSAW 0022-3697Stevens, K.W.H., (1952) Proc. Phys. Soc., London, Sect. a, 65, p. 209. , PPSAAM 0370-1298 10.1088/0370-1298/65/3/308Purwins, H.G., Leson, A., (1990) Adv. Phys., 39, p. 309. , ADPHAH 0001-8732 10.1080/00018739000101511Bak, P., (1974) J. Phys. C, 7, p. 4097. , JPSOAW 0022-3719 10.1088/0022-3719/7/22/014Nereson, N., Olsen, C., Arnold, G., (1996) J. Appl. Phys., 37, p. 4575. , JAPIAU 0021-8979 10.1063/1.1708083Deenadas, C., Thompson, A.W., Graig, R.S., Wallace, W.E., (1971) J. Phys. Chem. Solids, 32, p. 1843. , JPCSAW 0022-3697Inoue, T., Sankar, S.G., Graig, R.S., Wallace, W.E., Gschneidner Jr., K.A., (1997) J. Phys. Chem. Solids, 38, p. 487. , JPCSAW 0022-3697Barbara, B., Boucherle, J.X., Michelutti, B., Rossignol, M.F., (1979) Solid State Commun., 31, p. 477. , SSCOA4 0038-1098Barbara, B., Rossignol, M.F., Boucherle, J.X., (1975) Phys. Lett., 55, p. 321. , PYLAAG 0375-9601 10.1016/0375-9601(75)90489-

Simulation of calcium phosphate species in aqueous solution: force field derivation

A new force field has been derived for the aqueous calcium phosphate system that aims to reproduce the key thermodynamic properties of the system, including free energies of hydration of the ions and the solubility of the solid mineral phases. Interactions of three phosphate anions (PO43-, HPO42-, and H2PO4-) with water were calibrated through comparison with the results obtained from ab initio molecular dynamics using both GGA and hybrid density functional theory with dispersion corrections. In the solid state, the force field has been evaluated by benchmarking against experiment and other existing models and is shown to reproduce the structural and mechanical properties well, despite the primary focus being on thermodynamics. To validate the force field, the thermodynamics of ion pairing for calcium phosphate species in water has been computed and shown to be in excellent agreement with experimental data