625 research outputs found
MOCVD Growth of ZnO Nanowires Through Colloidal and Sputtered Au Seed Via Zn[TMHD]2 Precursor
AbstractZinc oxide (ZnO) nanowire (NW) arrays were grown on Si (100) substrate by metal-organic chemical vapor deposition (MOCVD) via Zn[TMHD]2 as precursor. Here we adopted two different procedures to grow ZnO NWs namely, colloid and sputtered Au pre-deposition on Si (100) substrate. Comparative studies based on the morphology and growth behavior of ZnO NWs were performed. The grown ZnO NWs were characterized by field-emission scanning electron microscopy (FE-SEM), Atomic Force Microscopy (AFM), Co-focal laser scanning microscopy (CLSM), and Raman spectroscopy
Kerr nonlinearities and nonclassical states with superconducting qubits and nanomechanical resonators
We propose the use of a superconducting charge qubit capacitively coupled to
two resonant nanomechanical resonators to generate Yurke-Stoler states, i.e.
quantum superpositions of pairs of distinguishable coherent states 180
out of phase with each other. This is achieved by effectively implementing Kerr
nonlinearities induced through application of a strong external driving field
in one of the resonators. A simple study of the effect of dissipation on our
scheme is also presented, and lower bounds of fidelity and purity of the
generated state are calculated. Our procedure to implement a Kerr nonlinearity
in this system may be used for high precision measurements in nanomechanical
resonators.Comment: 5 pages, 2 figures, fixed typo
Subnational sustainable development: The role of vertical intergovernmental transfers in reaching multidimensional goals
Achieving sustainable development hinges on two critical factors: the subnational implementation of public policies and the efficient allocation of resources across regions through vertical intergovernmental transfers. We introduce a framework that links these two mechanisms for analyzing the impact of reallocating federal transfers in the presence of regional heterogeneity from development indicators, budget sizes, expenditure returns, and long-term structural factors. Our study focuses on the case of Mexico and its 32 states. Using an agent-based computational model, we estimate the development gaps that will remain by the year 2030, and characterize their sensitivity to changes in the states’ budget sizes. Then, we estimate the optimal distribution of federal transfers to minimize these gaps. Crucially, these distributions depend on the specific development objectives set by the national government, and by various interdependencies between the heterogeneous qualities of the states. This work sheds new light on the complex problem of budgeting for the Sustainable Development Goals at the subnational level, and it is especially relevant for the study of fiscal decentralization from the expenditure point of view
Somatotype and digital dermatoglyphic in mexican football players
La valoración de la forma corporal y de las capacidades físicas es una
necesidad para la selección, clasificación y entrenamiento de los jugadores de
futbol. El presente estudio examinó en futbolistas profesionales mexicanos (N =
49) la relación entre clases de somatotipo y clases de capacidades físicas de
acuerdo a dermatoglifia dactilar. Las frecuencias de clases de somatotipo y
clases de capacidad física fueron comparadas entre subgrupos de futbolistas.
Una mayor proporción de futbolistas se caracterizó por somatotipo mesomorfo
balanceado con dermatoglifia tipo 2 y 3 correspondiente a fuerza, fuerza explosiva y velocidad. Esto es consistente con hallazgos previos en futbolistas
chilenos y brasileños, extendiendo por tanto la evidencia disponible acerca de
somatotipo y dermatoglifia en futbolistas latinoamericanosEvaluating body shape and capacities is needed for selection, classification and
training of football players. The present study examined in Mexican male
football players (N = 49) the relationship between types of somatotype and
types of physical capacities according to digital dermatoglyphics. The
frequencies of types of somatotype and of physical capacities were compared
between football players subgroups. A higher proportion of football players was
characterised by a balanced mesomorph somatotype with dermatoglyphic type
2 and 3 corresponding to strength, explosive strength and velocity. This is
consistent with previous findings in Chilenean and Brazilian footballers,
Therefore extending the available evidence of somatotype and dermatoglyphics
in Latin American football player
Scale dependence of the quark masses and mixings: leading order
We consider the Renormalization Group Equations (RGE) for the couplings of
the Standard Model and its extensions. Using the hierarchy of the quark masses
and of the Cabibbo-Kobayashi-Maskawa (CKM) matrix our argument is that a
consistent approximation for the RGE should be based on the parameter . We consider the RGE in the approximation where we
neglect all the relative terms of the order and higher.
Within this approximation we find the exact solution of the evolution equations
of the quark Yukawa couplings and of the vacuum expectation value of the Higgs
field. Then we derive the evolution of the observables: quark masses, CKM
matrix, Jarlskog invariant, Wolfenstein parameters of the CKM matrix and the
unitarity triangle. We show that the angles of the unitarity triangle remain
constant. This property may restrict the possibility of new symmetries or
textures at the grand unification scale.Comment: 15 pages, 4 figures, author of one reference adde
Robust Estimators in Generalized Pareto Models
This paper deals with optimally-robust parameter estimation in generalized
Pareto distributions (GPDs). These arise naturally in many situations where one
is interested in the behavior of extreme events as motivated by the
Pickands-Balkema-de Haan extreme value theorem (PBHT). The application we have
in mind is calculation of the regulatory capital required by Basel II for a
bank to cover operational risk. In this context the tail behavior of the
underlying distribution is crucial. This is where extreme value theory enters,
suggesting to estimate these high quantiles parameterically using, e.g. GPDs.
Robust statistics in this context offers procedures bounding the influence of
single observations, so provides reliable inference in the presence of moderate
deviations from the distributional model assumptions, respectively from the
mechanisms underlying the PBHT.Comment: 26pages, 6 figure
Hexavalent Chromium (VI) Removal by Penicillium sp. IA-01
The objective of this work was to study the removal of chromium (VI) in aqueous solution by the fungus Penicillium sp. IA-01, isolated from polluted air with industrial vapors. To obtain the fungal biomass, pre-inoculums were performed in thioglycolate broth from a strain isolated from vapours contaminated with Cr (VI). The fungus was incubated for four weeks at ambient temperature, filtered, and washed three times with trideionized water. In preparing cellullar fractions, it was necessary to break the fungal cells with glass beads using a homogenizer being careful to keep the samples in frosty cold ice. To obtain the fungal biomass, the fungus was filtered and stored in an oven at 80°C, allowing it to dry for 48 h. Removal of Cr (VI) in vitro was evaluated using different cellular fractions and dead fungal biomass. We determine the optimal characteristics for metal removal in the reaction mixture. Concluding that the ideal conditions for the removal of Cr (VI) in the cell extracts were 37°C and pH 7.0, also we observ that the highest enzyme activity was in the mixed membrane fraction. In dead fungal biomass, the ideal conditions for removal of metal are 60°C and pH 1.0
Data-driven reconstruction of chaotic dynamical equations: the H\'enon-Heiles type system
In this study, the classical two-dimensional potential
, , is considered. At , the system is superintegrable and
integrable, respectively, whereas for it exhibits a richer chaotic
dynamics. For instance, at it coincides with the H\'enon-Heiles system.
The periodic, quasi-periodic and chaotic motions are systematically
characterized employing time series, Poincar\'e sections, symmetry lines and
the largest Lyapunov exponent as a function of the energy and the parameter
. Concrete results for the lowest cases are presented in complete
detail. This model is used as a benchmark system to estimate the accuracy of
the Sparse Identification of Nonlinear Dynamical Systems (SINDy) method, a
data-driven algorithm which reconstructs the underlying governing dynamical
equations. We pay special attention at the transition from regular motion to
chaos and how this influences the precision of the algorithm. In particular, it
is shown that SINDy is a robust and stable tool possessing the ability to
generate non-trivial approximate analytical expressions for periodic
trajectories as well
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