Miracle-dz/UniFAR-FTUs huggingface dataset:
ON THE USE OF REALISTIC FERMI PROBLEMS FOR INTRODUCING MATHEMATICAL MODELLING IN SCHOOL

In this paper uses an analytical tool refereed to as the MAD (Modelling Activity Diagram) framework adapted from Schoenfeld's parsing protocol coding scheme to address the issues of how to introduce mathematical modelling to upper secondary students. The work of three groups of students engaged in solving so called realistic Fermi problems were analysed using this framework, and it was observed that the processes involved in a typical mathematical modelling cycle were richly represented in the groups' solving processes. The importance of the social interactions within the groups was noted, as well as the extensive use of extra- mathematical knowledge used by the students during the problem solving session.
Pumping tests in heterogeneous aquifers: An analytical study of what can be obtained from their interpretation using Jacob's Method

Interpretation of pumping tests to estimate hydraulic parameter values is typically based on the assumption of aquifer homogeneity. The applicability of the traditional methods of interpretation in real aquifers can be questioned, since the evaluation of the drawdown curves observed at different locations in a single test may not result in one consistent set of hydraulic parameters. Thus most hydrogeologists tend to look at estimated transmissivities (T) as some average property of the medium, while estimated storativities (S) are disregarded in some cases, particularly when they are obtained from data measured at the pumping well. An analytical study of drawdown under radially convergent flow toward a single point in heterogeneous aquifers shows that large time drawdown values form a straight line on a drawdown versus log time plot. Jacob's method consists of obtaining estimates for T and S from the slope and intercept of this line. We find that even in a heterogeneous field, these estimates provide valuable information about the aquifer. Estimated T values for different observation points tend to converge to a single value, which corresponds to the effective T derived under parallel flow conditions. Estimated storativities, however, display higher variability, but the geometric mean of the Sest values can be used as an unbiased estimator of the actual S. Thus it appears that although Jacob's method was originally derived for homogeneous media, it can provide valuable information in real aquifers.
Spectral Energy Distributions, Ages, and Metallicities of Star Clusters in M33

In this paper, we present CCD spectrophotometry of the star clusters that were detected by Chandar, Bianchi, & Ford in the nearby spiral galaxy M33. The images were obtained with the Beijing Astronomical Observatory 60/90 cm Schmidt Telescope in 13 intermediate-band filters from 3800 to 10000 Å. The observations cover the whole area of M33 with a total integration of 32.75 hr from 1995 September 23 to 2000 August 28. This provides a multicolor map of M33 in pixels of 1. ″7 × 1. ″7. By aperture photometry, we obtain the spectral energy distributions of these star clusters. Using theoretical stellar population synthesis models, we also obtain the distributions of age and metallicity of these star clusters. These clusters formed continuously from ∼3 × 106–1010 yr and have a large span of metallicity from Z = 0.0004 to 0.05.
THERMODYNAMICS OF THE NEUTRAL-TO-IONIC TRANSITION AS CONDENSATION AND CRYSTALLIZATION OF CHARGE-TRANSFER EXCITATIONS

The pressure-temperature phase diagram of tetrathiafulvalene-p-chloranil, prototype for the neutral-to-ionic transition, is determined by neutron diffraction and nuclear quadrupole resonance and discussed in relation to thermally induced charge-transfer (CT) excitations. The respective role of ionicity and dimerization is highlighted. Supported by theoretical considerations taking into account the interplay between quantum and thermal effects, the experimental results show that this uncommon electronic-structural transition can be described in terms of condensation and crystallization of CT excitations with a solid-liquid-gas\char21{}like phase diagram.
Parity nonconservation in atomic phenomena

The general structure of weak electron-nucleon interactions qualitative consideration of parity non-conservation effects in atoms the hydrogen atom calculations of the mixing of opposite-parity levels in heavy atoms optical highly forbidden M1 transitions in heavy atoms optical activity of heavy-metal vapours - general considerations and calculations observation of optical activity of heavy-metal vapours P-odd nuclear forces - another source of parity violation in atoms what else can be discovered about weak interactions from experiments with heavy atoms weak interactions and optical isomers parity non-conservation in crystals weak interactions and low temperatures searching for T-invariance violation in atoms and molecules.
Adsorption and incorporation of silicon at GaN(0001) surfaces

We have studied the adsorption and incorporation of Si at GaN(0001) surfaces employing density-functional theory and scanning tunneling microscopy (STM). Calculating the surface energy of a large number of structures with various Si concentrations and various III–V ratios, we derive a phase diagram showing the energetically most stable surfaces as a function of the Si and N chemical potentials. Based on these results, we identify the surface reconstructions seen in STM, explain the incorporation mechanism of Si on GaN surfaces, and discuss under which conditions Si acts as an antisurfactant.
Stark broadening of spectral lines of multicharged ions of astrophysical interest - XIX. Na X spectral lines

Using a semiclassical perturbation approach, we have calculated electron-, pro ton-, and He III- im pact line widths and shifts for 57 Na X multiplets for perturber densities 10 17 - 10 24 cm -3 and temperatures K. For lower perturber densities, the Stark broadening parameters are proportional to the perturber density.
Infrared observations of the Uranian rings

Maps of the Uranian rings at 2.2 microns and spectrophotometric observations covering 2.0 to 2.4 and 2.9 to 3.9 microns are discussed. The maps reveal a 2:1 azimuthal brightness variation whose amplitude and phase are consistent with the width variation and apsidal precession of the epsilon ring. Comparison with models based on stellar occultation data leads to an upper limit of 0.01 on the normal optical depth of any broad (5000 km wide), diffuse component of the ring system. A significant east-west asymmetry, corresponding to a brightening of the near side of the rings relative to the far side, is unexplained. The spectrum of the rings is flat over the range 2.1 to 3.9 microns. There is no spectroscopic evidence for the presence of H2O.
Spin relaxation in GaAs quantum dots

The spin-relaxation time due to the electron-acoustic phonon scattering in GaAs quantum dots is studied after the exact diagonalization of the electron Hamiltonian with the spin-orbit coupling. Different effects such as the magnetic field, the quantum dot size, and the temperature on the spin-relaxation time are investigated in detail. Moreover, we show that the perturbation method widely used in the literature is inadequate in accounting for the electron structure and therefore the spin-relaxation time.
An experimental study of natural convection in a vertical cavity with discrete heat sources

Natural convection heat transfer in a tall vertical cavity (aspect ratio = 16.5), with one isothermal vertical cold wall, and eleven alternately unheated and flush-heated sections of equal height on the opposing vertical wall, is experimentally investigated. The flow visualization pictures for the ethylene glycol-filled cavity reveal a flow pattern consisting of primary, secondary, and tertiary flows. The heat transfer data and the flow visualization photographs indicate that the stratification is the primary factor influencing the temperature of the heated sections. This behavior persists for all the runs where the secondary flow cells cover a large vertical extend of the cavity. Based on the analysis of the photographs it is suggested that the turbulent flow should be expected when the local modified Rayleigh number is in the range of 9.3 {times} 10 {sup 11} to 1.9 {times} 10{sup 12}. It is found that discrete flush-mounted heating in the enclosure results in local Nusselt numbers that are nearly the same as those reported for a wide flush-mounted heater on a vertical plate. This is believed to be due to the fact that the present problems in inherently unstable, and the smallest temperature difference between a heated section and the cold wallmore » results in the onset of convection motion. « less
Mechanisms of particle deposition in a fully developed turbulent open channel flow

Particle dispersion and deposition in the region near the wall of a turbulent open channel is studied using direct numerical simulation of the flow, combined with Lagrangian particle tracking under conditions of one-way coupling. Particles with response times of 5 and 15, normalized using the wall friction velocity and the fluid kinematic viscosity, are considered. The simulations were performed until the particle phase reached a statistically stationary state before calculating relevant statistics. For both response times, particles are seen to accumulate strongly very close to the wall in the form of streamwise oriented streaks. Deposited particles were divided into two distinct populations; those with large wall-normal deposition velocities and small near-wall residence times referred to as the free-flight population, and particles depositing with negligible wall-normal velocities and large near-wall residence times (more than 1000 wall time units), referred to as the diffusional deposition population.
Hyperbolic systems of conservation laws : the one-dimensional Cauchy problem

This book provides a self-contained introduction to the mathematical theory of hyperbolic systems of conservation laws, with particular emphasis on the study of discontinuous solutions, characterized by the appearance of shock waves. This area has experienced substantial progress in very recent years thanks to the introduction of new techniques, in particular the front tracking algorithm and the semigroup approach. These techniques provide a solution to the long standing open problems of uniqueness and stability of entropy weak solutions. This monograph is the first to present a comprehensive account of these new, fundamental advances, mainly obtained by the author together with several collaborators. It also includes a detailed analysis of the stability and convergence of the front tracking algorithm. The book is addressed to graduate students as well as researchers. Both the elementary and the more advanced material are carefully explained, helping the reader's visual intuition with over 70 figures. A set of problems, with varying difficulty, is given at the end of each chapter. These exercises are designed to verify and expand a student's understanding of the concepts and techniques previously discussed. For researchers, this book will provide an indispensable reference for the state of the art, in the field of hyperbolic systems of conservation laws. The last chapter contains a large, up to date list of references, preceded by extensive bibliographical notes.
Convergence of Triangular Transformations of Measures

We prove that if a Borel probability measure $\mu$ on a countable product of Souslin spaces satisfies a certain condition of atomlessness, then for every Borel probability measure $\nu$ on this product, there exists a triangular mapping $T_{\mu,\nu}$ that takes $\mu$ to $\nu$. It is shown that in the case of metrizable spaces one can choose triangular mappings in such a way that convergence in variation of measures $\mu_n$ to $\mu$ and of measures $\nu_n$ to $\nu$ implies convergence of the mappings $T_{\mu_n,\nu_n}$ to $T_{\mu,\nu}$ in measure $\mu$.
A topos formulation of history quantum theory

Topos theory has been suggested by Doring and Isham as an alternative mathematical structure with which to formulate physical theories. In particular, it has been used to reformulate standard quantum mechanics in such a way that a novel type of logic is used to represent propositions. In this paper we extend this formulation to include temporally ordered collections of propositions as opposed to single-time propositions. That is to say, we have developed a quantum history formalism in the language of topos theory where truth values can be assigned to temporal propositions. We analyze the extent to which such truth values can be derived from the truth values of the constituent, single-time propositions.
CRESCIMENTO DE CLONE DE Eucalyptus urophylla x E. grandis EM DIFERENTES ESPAÇAMENTOS

Abstract This research aims to evaluate the growth of clones of Eucalyptus urophylla x E. grandis at different spacing, between the age of three and six years, in Avare - SP. Treatments consisted of planting space as follows: 3,0 x 1,0; 3,0 x 1,5; 3,0 x 2,0 and 3,0 x 2,5 m. We evaluated DAP (diameter of soil) and height. We calculated the volume per tree of the six years old ones. Since the age of 3 years, plants in space 3,0 x 1,0 m had mean height and DAP lower than the ones in different spacing. At age 6, the trees of spacing 3,0 x 2,5 and 3,0 x 2,0 m revealed significantly higher average growth than the ones in spacing of 3,0 x 1,0 m. As conclusion, the most appropriate spacing for the region we worked is 3,0 x 2,0 m. Keywords : Planting density; Eucalyptus urograndis ; forest site.
Improved particle filter for nonlinear problems

The Kalman filter provides an effective solution to the linear Gaussian filtering problem. However where there is nonlinearity, either in the model specification or the observation process, other methods are required. Methods known generically as 'particle filters' are considered. These include the condensation algorithm and the Bayesian bootstrap or sampling importance resampling (SIR) filter. These filters represent the posterior distribution of the state variables by a system of particles which evolves and adapts recursively as new information becomes available. In practice, large numbers of particles may be required to provide adequate approximations and for certain applications, after a sequence of updates, the particle system will often collapse to a single point. A method of monitoring the efficiency of these filters is introduced which provides a simple quantitative assessment of sample impoverishment and the authors show how to construct improved particle filters that are both structurally efficient in terms of preventing the collapse of the particle system and computationally efficient in their implementation. This is illustrated with the classic bearings-only tracking problem.
HSTUV measurements of wind structure and velocities in Local Group OB stars

Archival HST FOS and GHRS data sets have been used to collect ultraviolet evidence for large- and small-scale stellar wind structure in extragalactic Local Group OB stars (i.e. SMC, LMC including R136, M31, M33 and NGC 6822). By comparison with previous studies of Galactic OB stars, wind activity is principally diagnosed in individual spectrograms via the presence of 'narrow absorption components' and saturated 'black' absorption troughs in the resonance line doublets. Their characteristics broadly suggest that these stars share the same physical mechanisms for perturbing the winds as those that act in Galactic stars. Both of these spectral indicators are also used to provide reliable measures of wind terminal velocities. These velocities are directly compared with previously published Galactic values, without reliance on model profile fitting. Relative to Galactic OB stars, the most discrepant terminal velocities (and wind line profiles) result from main-sequence early O-type stars in the SMC.
The Oort cloud and the Galaxy - Dynamical interactions

The results of recent dynamical studies of the Oort cloud and its interaction with the Galaxy are discussed. Various studies which used Monte Carlo simulations to investigate the evolution of comets in the Oort cloud and the manner in which they are injected into the planetary region are reviewed. Work done on perturbation of cometary orbits by stars, interstellar clouds, and the Galaxy is examined. The growing consensus that there is a massive inner Oort cloud with a population up to 100 times that of the dynamically active outer cloud is addressed. Variations on the Oort hypothesis are discussed. It is argued that speculations about the existence of a small unseen solar companion star or a tenth planet causing periodic comet showers from the inner Oort cloud are not supported by dynamical studies or analyses of the terrestrial and lunar cratering record. Evidence for Oort clouds around other stars is summarized.
A method for obtaining the maximum multiroute flows in a network

In a communication network, a multiroute channel is more reliable than is an ordinary channel against link or terminal failures. An m-route flow corresponds to a set of m-route channels, where m is the number of disjoint paths the m-route channel passes through. The max-flow min-cut theorem of the m-route flow has been proved by Kishimoto and Takeuchi. We show how to obtain the maximum m-route flow between two vertices. First, we evaluate the maximum value of m-route flows between two vertices by at most m times calculations of the maximum value of ordinary flows. Then, we construct the m-route flow with the maximum value. The correctness of this method gives another proof of Kishimoto and Takeuchi's max-flow min-cut theorem. The maximum value of m-route flows corresponds to the maximum capacity by m-route channels between two terminals.
On Basis-Conjugating Automorphisms of Free Groups

Let X = {x 1, … xn } be a free generating set of the free group Fn and let H be the subgroup of Aut Fn consisting of those automorphisms α such that α(xi ) is conjugate to xi for each i = 1, 2 , …, n. We call H the Z-conjugating subgroup of Aut Fn . In [1] Humphries found a generating set for the isomorphic copy H 1 of H consisting of Nielsen transformations where each is conjugate to ui (see remark 1 below). The purpose of this paper is to find a presentation of H (and hence of H 1). Let i ≠ j be elements of {1, 2, …, n}. We denote by (xi ; xj ) the automorphism of Fn which sends xi to and fixes xk if k ≠ i. Let S be the set of all such automorphisms.
Odd perfect numbers not divisible by 3. II

We prove that odd perfect numbers not divisible by 3 have at least eleven distinct prime factors. 1. N is called a perfect number if u(N) -2N, where o(N) is the sum of positive divisors of N. Twenty-seven even perfect numbers are known; however. no odd perfect (OP) numbers have been found. Suppose N is OP and o(N) is the number of distinct prime factors of N. Gradstein (1925), Kuihnel (1949), Weber (1951), and the author (1978, [5]) proved that w(N) 6. Pomerance (1972, [7]) and Robbins (1972) proved that w(N) ? 7. Hagis (1975, [2]) and Chein (1978, [ 1]) proved that (NA) ? 8. Hagis and McDaniel [3] proved that the largest prime factor of N ? 100129, and Pomerance [8] proved that the second largest prime factor of N 7 139. If 31 N, then Kanold (1949) proved that o(N) : 9, and the author (1977, [4]) proved that c(N) > 10. In this paper we prove THEOREM. If N is OP and 31 N, then w1N) > 1 1. 2. In the remainder of this paper we assume that N is OP and
Tunisian maltreating mothers characteristics

Introduction the aim of our cross-sectional study was to compare the sociodemographic and clinical characteristics, the social support, the personal history of abuse, and the parental bonding style of maltreating Tunisian mothers to those of nonmaltreating mothers. Methods this was a cross-sectional study carried out on the child psychiatry department of Mongi Slim Hospital in Tunisia. A data-collection sheet was designed to collect sociodemographic and clinical data about the child and the maltreatment (type, frequency, and duration), the mother of the child (sociodemographic and clinical data) and the family (socioeconomic situation and conjugal violence). Results the sample was composed of 167 mothers. Children were significantly more maltreated when their ages were between 6 and 12 years (p=0.004) and less maltreated when they had been born prematurely (p=0.007). Also, the higher the level of the mother´s education, the less the child was maltreated (p=0.007). In addition, maltreated mothers more frequently had a history of physical abuse, emotional abuse, or emotional neglect during their childhood (p values were respectively 0.002, 0.05, and 0.007). Thus, when mothers maltreated their children, a perception of optimal grandmother-mother parenting was significantly less frequent, and a perception of an affectionless-bonding grandmother-mother was significantly frequent (p = 0.019). Conclusion we conclude that it is important to consider individual, relational, communal, and social factors to elaborate efficient strategies for preventing children maltreatment.
On the solution of the differential equation

with a given initial condition x(t 0) at t = t 0 is a time function (waveform) which satisfies both the differential equation and the initial condition. () x t dx x dt τ τ ∞ = − + ˆ () x t x 0 () x t 0 t 0 t ˆ () x x t =
Deep magma storage during the 2021 La Palma eruption

The 2021 La Palma eruption provided an unpreceded opportunity to test the relationship between earthquake hypocenters and the location of magma reservoirs. We performed density measurements on CO2-rich fluid inclusions (FIs) hosted in olivine crystals that are highly sensitive to pressure via calibrated Raman spectroscopy. This technique can revolutionize our knowledge of magma storage and transport during an ongoing eruption, given that it can produce precise magma storage depth constraints in near real time with minimal sample preparation. Our FIs have CO2 recorded densities from 0.73 to 0.98 g/cm3, translating into depths of 15 to 27 km, which falls within the reported deep seismic zone recording the main melt storage reservoir.
Morphological and molecular evidence gives insight into the taxonomic position of Peucedanumpubescens (Apiaceae, Selineae)

﻿Abstract In this study, morphological and molecular evidences were combined to determine the taxonomic position of Peucedanumpubescens Hand. -Mazz. Morphologically, Peucedanumpubescens is similar to the species of the genus Ligusticopsis in having fibrous remnant sheaths at the stem base, pinnate and linear coexisted bracts, strongly compressed dorsally mericarps, filiform median and lateral ribs, winged marginal ribs, numerous vittae in each furrow and commissure, but can also be easily distinguished from members of Ligusticopsis by its hispid fruit and linear-lanceolate bracteoles. Molecular phylogenetic analyses based on the single-copy protein-coding sequences (CDS) of plastomes and internal transcribed space (ITS) region showed that Peucedanumpubescens nested in the genus Ligusticopsis. As both morphological and molecular data supported the inclusion of Peucedanumpubescens within Ligusticopsis, the species is here transferred and the new combination, Ligusticopsispubescens (Hand.-Mazz.) J.J.Deng, C.K. Liu & X.J.He, made.