Pressure dependence of the Shubnikov-de Haas oscillation pectrum of beta''-(BEDT-TTF)4(NH4)[Cr(C2O4)3].DMF

The Shubnikov-de Haas (SdH) oscillation spectra of the beta''-(BEDT-TTF)4(NH4)[Cr(C2O4)\_3].DMF organic metal have been studied in pulsed magnetic fields of up to either 36 T at ambient pressure or 50 T under hydrostatic pressures of up to 1 GPa. The ambient pressure SdH oscillation spectra can be accounted for by up to six fundamental frequencies which points to a rather complex Fermi surface (FS). A noticeable pressure-induced modification of the FS topology is evidenced since the number of frequencies observed in the spectra progressively decreases as the pressure increases. Above 0.8 GPa, only three compensated orbits are observed, as it is the case for several other isostructural salts of the same family at ambient pressure. Contrary to other organic metals, of which the FS can be regarded as a network of orbits, no frequency combinations are observed for the studied salt, likely due to high magnetic breakdown gap values or (and) high disorder level evidenced by Dingle temperatures as large as about 7 K.Comment: To be published in European Physical Journal

Photovoltaic module segmentation and thermal analysis tool from thermal images

The growing interest in the use of clean energy has led to the construction of increasingly large photovoltaic systems. Consequently, monitoring the proper functioning of these systems has become a highly relevant issue.In this paper, automatic detection, and analysis of photovoltaic modules are proposed. To perform the analysis, a module identification step, based on a digital image processing algorithm, is first carried out. This algorithm consists of image enhancement (contrast enhancement, noise reduction, etc.), followed by segmentation of the photovoltaic module. Subsequently, a statistical analysis based on the temperature values of the segmented module is performed.Besides, a graphical user interface has been designed as a potential tool that provides relevant information of the photovoltaic modules.Comment: 7 pages, 12 Figure

Evaluating the capacity of human gut microorganisms to colonize the zebrafish larvae (Danio rerio)

Indexación: Scopus.In this study we evaluated if zebrafish larvae can be colonized by human gut microorganisms. We tested two strategies: (1) through transplantation of a human fecal microbiota and (2) by successively transplanting aerotolerant anaerobic microorganisms, similar to the colonization in the human intestine during early life. We used conventionally raised zebrafish larvae harboring their own aerobic microbiota to improve the colonization of anaerobic microorganisms. The results showed with the fecal transplant, that some members of the human gut microbiota were transferred to larvae. Bacillus, Roseburia, Prevotella, Oscillospira, one unclassified genus of the family Ruminococcaceae and Enterobacteriaceae were detected in 3 days post fertilization (dpf) larvae; however only Bacillus persisted to 7 dpf. Successive inoculation of Lactobacillus, Bifidobacterium and Clostridioides did not improve their colonization, compared to individual inoculation of each bacterial species. Interestingly, the sporulating bacteria Bacillus clausii and Clostridioides difficile were the most persistent microorganisms. Their endospores persisted at least 5 days after inoculating 3 dpf larvae. However, when 5 dpf larvae were inoculated, the proportion of vegetative cells in larvae increased, revealing proliferation of the inoculated bacteria and better colonization of the host. In conclusion, these results suggest that it is feasible to colonize zebrafish larvae with some human bacteria, such as C. difficile and Bacillus and open an interesting area to study interactions between these microorganisms and the host. © 2018 Valenzuela, Caruffo, Herrera, Medina, Coronado, Feijóo, Muñoz, Garrido, Troncoso, Figueroa, Toro, Reyes-Jara, Magne and Navarrete.https://www.frontiersin.org/articles/10.3389/fmicb.2018.01032/ful

Strong enhancement of superconductivity at high pressures within the charge-density-wave states of 2H-TaS 2 and 2H-TaSe 2

We present measurements of the superconducting and charge density wave critical temperatures (Tc and TCDW) as a function of pressure in the transition metal dichalchogenides 2H-TaSe2 and 2H-TaS2. Resistance and susceptibility measurements show that Tc increases from temperatures below 1 K up to 8.5 K at 9.5 GPa in 2H-TaS2 and 8.2 K at 23 GPa in 2H-TaSe2. We observe a kink in the pressure dependence of TCDW at about 4 GPa that we attribute to the lock-in transition from incommensurate CDW to commensurate CDW. Above this pressure, the commensurate TCDW slowly decreases coexisting with superconductivity within our full pressure range.Comment: Published in Phys. Rev B 93, 184512 (2016

Indication for the coexistence of closed orbit and quantum interferometer with the same cross section in the organic metal (ET)4(H3O)[Fe(C2O4)3].C6H4Cl2: Persistence of SdH oscillations above 30 K

Shubnikov-de Haas (SdH) and de Haas-van Alphen (dHvA) oscillations spectra of the quasi-two dimensional charge transfer salt $\beta$"-(ET)$_4$(H$_3$O)[Fe(C$_2$O$_4$)$_3$]$\cdot$C$_6$H$_4$Cl$_2$ have been investigated in pulsed magnetic fields up to 54 T. The data reveal three basic frequencies F$_a$, F$_b$ and F$_{b - a}$, which can be interpreted on the basis of three compensated closed orbits at low temperature. However a very weak thermal damping of the Fourier component F$_b$, with the highest amplitude, is evidenced for SdH spectra above about 6 K. As a result, magnetoresistance oscillations are observed at temperatures higher than 30 K. This feature, which is not observed for dHvA oscillations, is in line with quantum interference, pointing to a Fermi surface reconstruction in this compound.Comment: published in Eur. Phys. J. B 71 203 (2009

Exact quantum statistics for electronically nonadiabatic systems using continuous path variables

We derive an exact, continuous-variable path integral (PI) representation of the canonical partition function for electronically nonadiabatic systems. Utilizing the Stock-Thoss (ST) mapping for an N-level system, matrix elements of the Boltzmann operator are expressed in Cartesian coordinates for both the nuclear and electronic degrees of freedom. The PI discretization presented here properly constrains the electronic Cartesian coordinates to the physical subspace of the mapping. We numerically demonstrate that the resulting PI-ST representation is exact for the calculation of equilibrium properties of systems with coupled electronic and nuclear degrees of freedom. We further show that the PI-ST formulation provides a natural means to initialize semiclassical trajectories for the calculation of real-time thermal correlation functions, which is numerically demonstrated in applications to a series of nonadiabatic model systems.Comment: 10 pages, 6 figure

Spin qubits with electrically gated polyoxometalate molecules

Spin qubits offer one of the most promising routes to the implementation of quantum computers. Very recent results in semiconductor quantum dots show that electrically-controlled gating schemes are particularly well-suited for the realization of a universal set of quantum logical gates. Scalability to a larger number of qubits, however, remains an issue for such semiconductor quantum dots. In contrast, a chemical bottom-up approach allows one to produce identical units in which localized spins represent the qubits. Molecular magnetism has produced a wide range of systems with tailored properties, but molecules permitting electrical gating have been lacking. Here we propose to use the polyoxometalate [PMo12O40(VO)2]q-, where two localized spins-1/2 can be coupled through the electrons of the central core. Via electrical manipulation of the molecular redox potential, the charge of the core can be changed. With this setup, two-qubit gates and qubit readout can be implemented.Comment: 9 pages, 6 figures, to appear in Nature Nanotechnolog

Specification of Complex Logical Expressions for Task Automation: An EUD Approach

The growing availability of smart objects is stimulating researchers in investigating the IoT phenomenon from different perspectives. In the HCI area, and in particular from the EUD perspective, one prominent goal is to enable nontechnical users to be directly involved in configuring smart object behaviour. With this respect, this paper discusses three visual composition techniques to specify logical expressions in Event-Condition-Action rules used for synchronizing the behavior of smart objects

Experimental investigations of the sub-Coulomb 12C+12C and 12C+16O reactions

Cluster resonances in light heavy-ion systems like 12C+12C and 12C+16O may have a major impact on astrophysics stellar scenarios. Resonant radiative capture reactions have been studied for these systems at energies at and slightly below their Coulomb barriers to investigate the possible 12C-12C and 12C-16O molecular origin of the resonances. Spins have been attributed to the resonances and specificities of their γ-decay have been identified. At deep sub-barrier energies, a fusion cross section measurement using the particle-γ coincidence technique is discussed for the 12C+12C system. A new project is presented to possibly extend the 12C+12C S low-energy S factor study

Efecto de las fuentes de polen sobre el rendimiento en la extracción de aceite y perfil de ácidos grasos de las semillas de dátil (Phoenix dactylifera L.) cultivar Medjool de México

The present investigation aimed to assess the effect of pollen sources on the mass, dimension, oil content and fatty acid profile of the seeds from female palms of the Medjool date cultivar. The palms were pollinated with Deglet Noor, Khadrawy, Medjool and Zahidi cultivars. In addition, three palms were pollinated as the treatment control. The fatty acids were evaluated by gas chromatography-mass spectrometry. The surface morphology of date seed powder was examined using SEM, before and after n-hexane interaction. The seeds of the Medjool treatment had the greatest mass (1.42 g), but the lowest oil content (5.37% w/w); the control seeds showed smaller mass (1.21 g), but higher oil content (13.57% w/w). The proportion of fatty acids varied significantly among the treatments with respect to the control. The most abundant fatty acids were oleic (C18:1), lauric (C12:0), myristic (C14:0), palmitic (C16:0), linoleic (C18:2), and stearic (C18:0). Together these fatty acids presented a composition between 98.3 and 98.67% for treatments, and 99.0% for the control. The results indicate that the pollen sources from Deglet Noor, Khadrawy, Medjool and Zahidi cultivars had a significant effect on mass, dimension, oil content and fatty acid profile of the seeds of the date cultivar Medjool. The date seed oil could be used as edible oil, in food products, and in pharmaceutical and cosmetic applications.La presente investigación tuvo como objetivo evaluar el efecto de las fuentes de polen, sobre la masa, dimensión, contenido de aceite y el perfil de ácidos grasos de las semillas de dátil del cultivar Medjool. Las palmas hembras del cultivar Medjool fueron polinizadas con cultivares Deglet Noor, Khadrawy, Medjool y Zahidi. Además, tres palmas fueron polinizadas como tratamiento control. Los ácidos grasos se evaluaron por cromatografía de gases-espectrometría de masas. La morfología de la superficie del polvo de semillas de dátil se examinó utilizando un equipo SEM, antes y después de la interacción n-hexano. Las semillas del tratamiento Medjool resultaron con mayor masa (1,42 g), pero menor contenido de aceite (5,37% p/p); la semilla control, mostró una masa más pequeña (1,21 g), pero un mayor contenido de aceite (13,57% p/p). La composición de ácidos grasos varió significativamente entre los tratamientos con respecto al control. Los ácidos grasos mayoritarios fueron: oleico (C18:1), láurico (C12:0), mirístico (C14:0), palmítico (C16:0), linoleico (C18:2) and esteárico (C18:0). En total, estos ácidos grasos alcanzan una composición entre 98.3 y 98.67% para los tratamientos, y 99.0% para el control. Los resultados indican que la fuente de polen de los cultivares Deglet Noor, Khadrawy, Medjool y Zahidi tiene un efecto significativo sobre la masa, dimensión, contenido de aceite y el perfil de ácidos grasos de la semilla del cultivar de dátil Medjool. El aceite de la semilla de dátil, podría usarse como aceite comestible, productos alimenticios, aplicaciones farmacéuticas y cosméticas