13,512 research outputs found
Mammalia, Chiroptera, Molossidae, <i>Molossops temminckii</i> (Burmeister, 1854), and Vespertilionidae, <i>Eptesicus furinalis</i> (dOrbigny and Gervais, 1847): New locality record and distribution extension in Cordoba Province, Argentina
During a field trip to the Ramsar site âBañados del RĂo Dulce y Laguna Mar Chiquitaâ we captured three specimensof Molossops temminckii (Burmeister, 1854) and two of Eptesicus furinalis (dâOrbigny and Gervais, 1847). Molossopstemminckii has a wide distribution in Argentina, but this new record represents the second mention of the species for theCordoba Province after 13 years. The specimens of E. furinalis represent the tenth record for Cordoba and the second for RĂoPrimero Department. This new information reflects the scarcity of systematic studies on bats in Cordoba Province
Magnetic transitions in Pr2NiO4 single crystal
The magnetic properties of a stoichiometric Pr2NiO4 single crystal have been examined by means of the temperature dependence of the complex ac susceptibility and the isothermal magnetization in fields up to 200 kOe at T=4.2 K. Three separate phases have been identified and their anisotropic character has been analyzed. A collinear antiferromagnetic phase appears first between TN = 325 K and Tc1 = 115 K, where the Pr ions are polarized by an internal magnetic field. At Tc1 a first modification of the magnetic structure occurs in parallel with a structural phase transition (Bmab to P42/ncm). This magnetic transition has a firstâorder character and involves both the outâofâplane and the inâplane spin components (magnetic modes gx and gxcyfz, respectively). A second magnetic transition having also a firstâorder character is also clearly identified at Tc2 = 90 K which corresponds to a spin reorientation process (gxcyfz to cxgyaz magnetic modes). It should be noted as well that the outâofâphase component of Ïac shows a peak around 30 K which reflects the coexistence of both magnetic configurations in a wide temperature interval. Finally, two fieldâinduced transitions have been observed at 4.2 K when the field is directed along the c axis. We propose that the highâfield anomaly arises from a metamagnetic transition of the weak ferromagnetic component, similarly to La2CuO4
On the vulnerability of iris-based systems to a software attack based on a genetic algorithm
The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-642-33275-3_14Proceedings of 17th Iberoamerican Congress, CIARP 2012, Buenos Aires, ArgentinaThe vulnerabilities of a standard iris verification system to a novel indirect attack based on a binary genetic algorithm are studied. The experiments are carried out on the iris subcorpus of the publicly available BioSecure DB. The attack has shown a remarkable performance, thus proving the lack of robustness of the tested system to this type of threat. Furthermore, the consistency of the bits of the iris code is analysed, and a second working scenario discarding the fragile bits is then tested as a possible countermeasure against the proposed attack.This work has been partially supported by projects Contexts (S2009/TIC-1485) from CAM, Bio-Challenge (TEC2009-11186) from Spanish MICINN, TABULA RASA (FP7-ICT-257289) and BEAT (FP7-SEC-284989) from EU, and CĂĄtedra UAM-TelefĂłnica
Bounds for Lepton Flavor Violation and the Pseudoscalar Higgs in the General Two Higgs Doublet Model using muon factor
Current experimental data from the muon factor, seems to show the
necessity of physics beyond the Standard Model (SM), since the difference
between SM and experimental predictions is 2.6. In the framework of
the General Two Higgs Doublet Model (2HDM), we calculate the muon anomalous
magnetic moment to get lower and upper bounds for the Flavour Changing (FC)
Yukawa couplings in the leptonic sector. We also obtain lower bounds for the
mass of the pseudoscalar Higgs () as a function of the parameters of
the model.Comment: 12 pages, RevTex4, 5 figures. Improved presentation, updated
experimental data, amplified analysis, new figures added. Subbmited to Phys.
Rev.
Preparation of Dipteran Larvae for Scanning Electron Microscopy with Special Reference to Myiasigen Dipteran Species
Although controversy exists concerning the role of chemical fixatives in scanning electron microscopy (SEM) studies of Dipteran larvae, we have observed that filtered 10% formaldehyde solution gives excellent results as a preservative. After immersing in vivo in formaldehyde, the larvae material is preserved for prolonged periods (up to 8 months), before examination with SEM. As a fixative, formaldehyde preserves the structure of the larval cuticle and produces no visible artifacts. Moreover, postfixation is not necessary.
Due to pecularities of the way of life of Wohlfahrtia magnifica (principally the accumulations of necrotic tissue, purulent particles, and other types of substances that often adhere to the numerous spines of larvae), this species must be cleaned before examination by SEM. Manual cleaning with alternating bidistilled water and 0.9% saline solution proved to be a rapid, easy and inexpensive method that gave good results.
Both lyophilization drying and critical point drying were used before sputtering the material. While lyophilization drying proved to be the most effective method for instars II and III, critical point drying was the best technique for study of specimens belonging to instar I. The optimum time for drying and conditions for lyophilization and sputter-coating with gold were determined experimentally. Samples were mounted on SEM stubs with double-sided adhesive and silver conductive paint.
The method proposed is easy and effective for the SEM study of larvae myiasis-producing diptera
Effect of the Diesel, Inhibitor, and CO 2
In order to determine the diesel contribution in the coadsorption process of the oil-soluble inhibitors, electrochemical impedance spectroscopy measurements have been carried out to study the performance of oil-soluble inhibitors in both presence and absence of diesel and CO2. The results showed that the presence of the oil phase provides some protection to the steel because the water-soluble fractions are capable of being adsorbed on the steel surface thereby reducing the corrosion rate. The oily phase does not contribute to the adsorption process of the inhibitor because the inhibitor is absorbed into the water-soluble fractions. The oil-soluble inhibitors are effective only when the solution is saturated with CO2. CO2 saturation causes a decrease in the pH of the solution causing both an increase of the inhibitor solubility and a better dispersion of the inhibitor into the electrolyte
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