Analogous Transitions Research Articles

Evidence for Pliocene–Quaternary normal faulting in the hinterland of the Bhutan Himalaya

In the central Himalaya, past researchers have identified a distinctive transition from the physiographic Lower Himalayan ranges in the south to the Higher Himalayan ranges in the north. Local relief and hillslope gradient, as well as erosion and surface uplift rates, increase abruptly across this transition to the north. In the eastern Himalaya, the same physiographic transition exists, but it is less dramatic. We describe here a previously undocumented steep, north-dipping, brittle structure that is roughly coincident with this physiographic transition in eastern Bhutan—the Lhuentse fault. Low-temperature (U-Th)/He apatite data suggest that the Lhuentse fault has been active since the Pliocene, and (U-Th)/He dates on offset hydrothermal hematite deposits from within the fault zone demonstrate a component of Quaternary slip. Although we identified no definitive evidence of fault kinematics based on field or petrographic analysis of the fault rocks, the disrupted pattern of (U-Th)/He apatite dates suggests normal-sense displacement, contrary to what was expected given previous studies of an analogous transition in the central Himalaya. We regard the existence and activity of the Lhuentse fault as evidence of (1) recent evolution in the tectonic regime of the eastern Himalaya from one of near-exclusive north-south shortening to one in which both transcurrent and normal faulting are increasingly important in the region north of the Himalayan deformation front, or (2) an active duplex south of the physiographic transition in the middle latitudes of Bhutan.

Direct Observation of Photodissociation Products from Phenylperoxyl Radicals Isolated in the Gas Phase

Gas phase peroxyl radicals are central to our chemical understanding of combustion and atmospheric processes and are typically characterized by strong absorption in the UV (λ(max) ≈ 240 nm). The analogous maximum absorption feature for arylperoxyl radicals is predicted to shift to the visible but has not previously been characterized nor have any photoproducts arising from this transition been identified. Here we describe the controlled synthesis and isolation in vacuo of an array of charge-substituted phenylperoxyl radicals at room temperature, including the 4-(N,N,N-trimethylammonium)methyl phenylperoxyl radical cation (4-Me3N([+])CH2-C6H4OO(•)), using linear ion-trap mass spectrometry. Photodissociation mass spectra obtained at wavelengths ranging from 310 to 500 nm reveal two major photoproduct channels corresponding to homolysis of aryl-OO and arylO-O bonds resulting in loss of O2 and O, respectively. Combining the photodissociation yields across this spectral window produces a broad (FWHM ≈ 60 nm) but clearly resolved feature centered at λ(max) = 403 nm (3.08 eV). The influence of the charge-tag identity and its proximity to the radical site are investigated and demonstrate no effect on the identity of the two dominant photoproduct channels. Electronic structure calculations have located the vertical B ← X transition of these substituted phenylperoxyl radicals within the experimental uncertainty and further predict the analogous transition for unsubstituted phenylperoxyl radical (C6H5OO(•)) to be 457 nm (2.71 eV), nearly 45 nm shorter than previous estimates and in good agreement with recent computational values.

49 Nucleic acids in anhydrous media: G-quadruplex folding governed by Kramers rate theory

Structures formed by human telomere sequence (HTS) DNA are of interest due to G-quadruplex forming HTS DNA that has recently generated a tremendous interest due to its involvement in aging process and cancer. The present study examines HTS in anhydrous, exceptionally viscous deep eutectic solvent (DES), comprised of choline, chloride, and urea. Under these conditions, HTS adopts an extremely stable “parallel-propeller” form of G-quadruplex, consistent with the previously observed effects of diminished water activity. Additionally, the high solvent friction of DES slows the dynamics of HTS folding on the order of months, as opposed to milliseconds in aqueous solution, and allows the entrapment of kinetic intermediates. Moreover, analogous transition studies of the quadruplex converting from the aqueous buffer structure to the parallel form in 90% DES (w/v) and 40% PEG 200 (v/v) differ from hours to days scaling inversely with viscosity ∼ 1/ƞ1.4. This diffusion control over the HTS folding is consistent with Kramers rate theory and these findings highlight the necessity to consider the viscosity of intracellular conditions when exploring the structure dynamics of telomeres and drug binding interactions. Lastly, tuning solvent viscosity could prove useful in the future study of G-quadruplex dynamics, and applied DNA nano-technology, where time dependent structural transitions are desired.

Preciseγ-ray intensity measurements in10B

Precise electromagnetic transition matrix elements in ${}^{10}$Be and ${}^{10}$C have provided surprisingly stringent tests of modern ab initio calculations using realistic nuclear forces. The analog transition in ${}^{10}$B can further constrain these new calculations and probe the symmetry of the wave functions across the $A=10$ multiplet. We report on a careful measurement of the $\ensuremath{\gamma}$-ray intensities from states populated in the ${}^{10}$B($p$,${p}^{\ensuremath{'}}$) reaction at 10 MeV, including a determination of the key $E$2 branch from the $J=2$ $T=1$ state at 5164 keV to the $J=0$ $T=1$ state at 1740 keV of 0.16(4)$%$.

COLLISIONAL EXCITATION OF THE [C II] FINE STRUCTURE TRANSITION IN INTERSTELLAR CLOUDS

We analyze the collisional excitation of the 158 micron (1900.5 GHz) fine structure transition of ionized carbon (C+) in terms of line intensities produced by simple cloud models. The single C+ fine structure transition is a very important coolant of the atomic interstellar medium and of photon dominated regions in which carbon is partially or completely in ionized form. The [CII] line is widely used as a tracer of star formation in the Milky Way and other galaxies. Excitation of the [CII] fine structure transition can be via collisions with hydrogen molecules, atoms, and electrons. Velocity-resolved observations of [CII] have become possible with the HIFI instrument on Herschel and the GREAT instrument on SOFIA. Analysis of these observations is complicated by the fact that it is difficult to determine the optical depth of the [CII] line due to the relative weakness and blending of the components of the analogous transition of 13C$+. We discuss the excitation and radiative transition of the [CII] line, deriving analytic results for several limiting cases and carry out numerical solutions using a large velocity gradient model for a more inclusive analysis. We show that for antenna temperatures up to 1/3 of the brightness temperature of the gas kinetic temperature, the antenna temperature is linearly proportional to the column density of C+ irrespective of the optical depth of the transition, which can be referred to as the effectively optically thin (EOT) approximation. We review the critical densities for excitation of the [CII] line by various collision partners. We briefly analyze C+ absorption and conclude with a discussion of C+ cooling and how the considerations for line intensities affect the behavior of this important coolant of the ISM.

The NHS and market forces in healthcare: the need for organisational ethics

The NHS in England is an organisation undergoing substantial change. The passage of the Health and Social Care Act 2012, consolidates and builds on previous health policies and introduces further...

Role of Met80 and Tyr67 in the Low-pH Conformational Equilibria of Cytochrome c

The low-pH conformational equilibria of ferric yeast iso-1 cytochrome c (ycc) and its M80A, M80A/Y67H, and M80A/Y67A variants were studied from pH 7 to 2 at low ionic strength through electronic absorption, magnetic circular dichroism, and resonance Raman spectroscopies. For wild-type ycc, the protein structure, axial heme ligands, and spin state of the iron atom convert from the native folded His/Met low-spin (LS) form to a molten globule His/H(2)O high-spin (HS) form and a totally unfolded bis-aquo HS state, in a single cooperative transition with an apparent pK(a) of ~3.0. An analogous cooperative transition occurs for the M80A and M80A/Y67H variants. This is preceded by protonation of heme propionate-7, with a pK(a) of ~4.2, and by an equilibrium between a His/OH(-)-ligated LS and a His/H(2)O-ligated HS conformer, with a pK(a) of ~5.9. In the M80A/Y67A variant, the cooperative low-pH transition is split into two distinct processes because of an increased stability of the molten globule state that is formed at higher pH values than the other species. These data show that removal of the axial methionine ligand does not significantly alter the mechanism of acidic unfolding and the ranges of stability of low-pH conformers. Instead, removal of a hydrogen bonding partner at position 67 increases the stability of the molten globule and renders cytochrome c more susceptible to acid unfolding. This underlines the key role played by Tyr67 in stabilizing the three-dimensional structure of cytochrome c by means of the hydrogen bonding network connecting the Ω loops formed by residues 71-85 and 40-57.

Electromechanical strain in Bi(Zn1/2Ti1/2)O3–(Bi1/2Na1/2)TiO3–(Bi1/2K1/2)TiO3 solid solutions

Solid solutions ceramics of the Bi(Zn0.5Ti0.5)O3–(Bi0.5K0.5)TiO3–(Bi0.5Na0.5)TiO3 ternary system for <20 mol. % BZT were created and confirmed to be single phase using x-ray diffraction. The dielectric dispersion showed decreasing Tmax of the dielectric spectrum with a broadening of the transition with increasing BZT content. At 2.5BZT–40BKT–57.5BNT, a secondary transition commonly observed for morphotropic phase boundary (MPB) BNT–BKT was observed. The ferroelectric behavior of the system was characterized by a transition where the polarization hysteresis showed a severe pinching effect on remanent polarization (20.8 μC/cm2 at 2.5% BZT) as BZT contents was increased (Pr = 2.3 μC/cm2 at 20% BZT). Similarly, as the temperature increased to 175 °C, the remanent polarization of the 2.5% BZT composition significantly reduced to 2.1 μC/cm2. The onset of this transition corresponds to the lower temperature frequency dispersion observed in the dielectric spectrum. The strain hysteresis experienced analogous transition to the polarization, with a change in shape from typical ferroelectric butterfly to a complete loss of negative strain as BZT concentration increased. Maximum strain values of 0.33% were observed at 5-40-55 accompanied by a large d33*=547pm/V.

Decays of T Z = − 3/2 nuclei 23Al, 31Cl, and 41Ti

This article gives an overview on the decay spectroscopy of T Z = –3/2 nuclei 23Al, 31Cl, and 41Ti performed at the Ion Guide Isotope Separator On-Line (IGISOL) facility. The results of the IGISOL experiments are compared to the experimental results that have been published since. The isobaric multiplet mass equation (IMME) has been studied for the T = 3/2 quartets at A = 23 and A = 31. For 41Ti, a detailed comparison to the Gamow–Teller strengths obtained for the analog transitions via charge-exchange reactions has been done. Further improvements in the experimental instrumentation and methods and possible implementations for studying T Z = –3/2 nuclei at the new IGISOL facility are discussed.

Phase transitions for random states and a semicircle law for the partial transpose

For a system of N identical particles in a random pure state, there is a threshold k_0 = k_0(N) ~ N/5 such that two subsystems of k particles each typically share entanglement if k > k_0, and typically do not share entanglement if k < k_0. By "random" we mean here "uniformly distributed on the sphere of the corresponding Hilbert space." The analogous phase transition for the positive partial transpose (PPT) property can be described even more precisely. For example, for N qubits the two subsystems of size k are typically in a PPT state if k < k_1 := N/4 - 1/2, and typically in a non-PPT state if k > k_1. Since, for a given state of the entire system, the induced state of a subsystem is given by the partial trace, the above facts can be rephrased as properties of random induced states. An important step in the analysis depends on identifying the asymptotic spectral density of the partial transposes of such random induced states, a result which is interesting in its own right.

Returning a Verdict on the Jury: How the Japanese Have Reacted to the Introduction of a Lay Judge System

AbstractThis article considers the reactions in Japan to the newly introduced quasi-jury system. It illustrates how first-hand experience with jury justice has transformed Japan from a country hostile to that institution to one where it is widely endorsed. This finding undermines the popular notion that Japan's legal culture is incongruous with this democratic institution, and thus augurs well for analogous transitions being made in other East Asian countries with legal traditions similar to that of Japan. Furthermore, it underlines the reasons why those countries in the West that are letting jury trial erode should perhaps think twice about doing so.

Synthesis, characterization and chemical properties of 1-((E)-2-pyridinylmethylidene)semicarbazone manganese(II) and iron(II) complexes

Abstract Manganese(II) perchlorate and iron(II) chloride react with 2-formylpyridine semicarbazone (HCSpy) in boiling ethanol to produce [Mn II (HSCpy) 2 ](ClO 4 ) 2 ·C 2 H 5 OH and [Fe II Cl(HSCpy)]Cl. The distorted octahedral manganese complex crystallizes in the triclinic system with space group P (-1). The ligand HSCpy is tridentate and is coordinated through two nitrogen and one oxygen atoms. Comparison of the bond distances with analogous transition metal complexes that have the same geometry revealed longer bonds for the manganese derivative, an outcome that correlates well with the radius of the metal ions. The iron(II) ion is tetracoordinated to one semicarbazone and one chloride. Mass spectrometry, conductivity measurements, Mossbauer, UV–VIS, FTIR and elemental analysis were all in accordance with the proposed composition and the plausible geometry of [FeCl(HSCpy)]Cl. Mass spectrometry unequivocally detected the presence of the [FeCl(HSCpy)] + ion with a m / z of 254.97 and intensity of 2 × 10 5 .

Application of catastrophe theory to neck initiation of metallocene-catalyzed high-density polyethylene

This paper deals with the initiation of necking in a high-density polyethylene. The necking initiation was explained by a first-order catastrophic phase transition in analogy of van der Waals gas. Catastrophic arrangement of the lamellar cluster units results in sudden emergence of the locally close-packed layer structure. The layered plate collapses by sliding the units and leads to necking.

An entropy driven phase transformation in a Au43.3Cu31.8Al24.9 shape-memory alloy

The 18-karat Au43.3Cu31.8Al24.9 alloy displays shape memory effect. The parent phase has L21 structure which transforms to B2 at high temperature. The B2 phase is retained in metastable state by quenching from the B2 field. It then transforms irreversibly with an endothermic peak in Differential Scanning Calorimetry (DSC) to the stable L21 structure in the temperature range between 407K and 435K as a function of heating rate. The transformation is, therefore, entropy-driven. Details are reported on the enthalpy of transformation and its temperature dependence. The transformation is discussed with reference to the entropy content of phases as a function of temperature which counteracts austenite stability. The role of vacancy motion is outlined. A comparison is made with analogous transitions occurring in molecular substances and metallic materials.

Geometric Convergence of Adaptive Monte Carlo Algorithms for Radiative Transport Problems Based on Importance Sampling Methods

Importance sampling is a very well-known variance-reducing technique used in Monte Carlo simulations of radiative transport. It involves a distortion of the physical (analog) transition probabilities with the goal of causing events of interest in the computation to occur more frequently than in the analog process. This distortion is then compensated by a corresponding alteration of the estimating random variable in order to remove any bias from the estimates of quantities of interest. In this paper, we construct several families of estimators based on importance sampling methods to solve general transport problems and prove that the adaptive application of each estimator produces geometric convergence of the approximate solution. We also present numerical results that illustrate important elements of the theory.

The eigenvalues and eigenvectors of finite, low rank perturbations of large random matrices

We consider the eigenvalues and eigenvectors of finite, low rank perturbations of random matrices. Specifically, we prove almost sure convergence of the extreme eigenvalues and appropriate projections of the corresponding eigenvectors of the perturbed matrix for additive and multiplicative perturbation models. The limiting non-random value is shown to depend explicitly on the limiting eigenvalue distribution of the unperturbed random matrix and the assumed perturbation model via integral transforms that correspond to very well-known objects in free probability theory that linearize non-commutative free additive and multiplicative convolution. Furthermore, we uncover a phase transition phenomenon whereby the large matrix limit of the extreme eigenvalues of the perturbed matrix differs from that of the original matrix if and only if the eigenvalues of the perturbing matrix are above a certain critical threshold. Square root decay of the eigenvalue density at the edge is sufficient to ensure that this threshold is finite. This critical threshold is intimately related to the same aforementioned integral transforms and our proof techniques bring this connection and the origin of the phase transition into focus. Consequently, our results extend the class of ‘spiked’ random matrix models about which such predictions (called the BBP phase transition) can be made well beyond the Wigner, Wishart and Jacobi random ensembles found in the literature. We examine the impact of this eigenvalue phase transition on the associated eigenvectors and observe an analogous phase transition in the eigenvectors. Various extensions of our results to the problem of non-extreme eigenvalues are discussed.

Returning a Verdict on the Jury: How the Japanese Have Reacted to the Introduction of a Lay Judge System

This article considers the reactions in Japan to the newly introduced quasi-jury system. It illustrates how first-hand experience with jury justice has transformed Japan from a country hostile to that institution to one where it is widely endorsed. This finding undermines the popular notion that Japan’s legal culture is incongruous with this democratic institution, and thus augurs well for analogous transitions being made in other East Asian countries with legal traditions similar to that of Japan. Furthermore, it underlines the reasons why those countries in the West that are letting jury trial erode should perhaps think twice about doing so.

Magnetic and dielectric properties of multiferroic Tb0.5Eu0.5MnO3

The structural, magnetic and dielectric properties of multiferroic compound Tb0.5Eu0.5MnO3 are reported near the boundary of the multiferroic phase of the Eu-doped Tb1−xEuxMnO3 system. The Mn3+ moments order in an incommensurate antiferromagnetic manner below TN = 50 K, followed by a spin canting-like response around 25 K. Below TN, extra hysteresis loops were observed for applied fields Ba around 1-2 T, with decreasing magnetic / K moment for increasing magnetic fields. The dielectric constant ϵ' showed a peak at 28, which was attributed to the ferroelectric transition in analogy with the parent compound TbMnO3. Structural analysis indicates the Mn-O2-Mn bond angle within the ab-plane is 145.9° suggesting that there exists a critical angle in the perovskite manganate multiferroic systems.

Experimental relative line strengths within selected multiplets of neutral sulfur from the visible and infrared spectral range

In a wall-stabilized cascade arc helium plasma with some traces of SF6 has been generated. On the basis of measured total line intensities emitted from the plasma, the relative line strengths within twelve multiplets of neutral sulfur (SI) have been determined. The studied lines cover the spectral range from 415 nm to 1046 nm. The obtained experimental line strengths are compared with results of recent theoretical data as well as with results of older experiments. In addition the SI line strength data are compared with analogous transitions in the OI spectrum.

Space-time phase transitions in driven kinetically constrained lattice models

Kinetically constrained models (KCMs) have been used to study and understand the origin of glassy dynamics. Despite having trivial thermodynamic properties, their dynamics slows down dramatically at low temperatures while displaying dynamical heterogeneity as seen in glass forming supercooled liquids. This dynamics has its origin in an ergodic-nonergodic first-order phase transition between phases of distinct dynamical "activity". This is a "space-time" transition as it corresponds to a singular change in ensembles of trajectories of the dynamics rather than ensembles of configurations. Here we extend these ideas to driven glassy systems by considering KCMs driven into non-equilibrium steady states through non-conservative forces. By classifying trajectories through their entropy production we prove that driven KCMs also display an analogous first-order space-time transition between dynamical phases of finite and vanishing entropy production. We also discuss how trajectories with rare values of entropy production can be realized as typical trajectories of a mapped system with modified forces.