232 research outputs found
Field-induced Orbital Patterns in Ferromagnetic Layered Ruthenates
We study the evolution of orbital patterns in ferromagnetic layered
ruthenates due to the competition of Coulomb interactions, compressive c axis
and orthorhombic distortions in the presence of a polarizing orbital field
coupled to the angular momentum. By means of the exact diagonalization on a 2x2
cluster and a cluster embedded analysis where inter-plaquette interaction is
treated on mean field level, we determine the ground-state phase diagram.
Specifically, we demonstrate that, via the activation of two or three of t_2g
local orbital configurations, an external field applied along different
symmetry directions can lead to inequivalent orbital correlated states.
Starting from an antiferro-orbital pattern, for the easy axis case an orbital
ordered phase is induced, having strong next nearest neighbors ferro-orbital
correlations. Otherwise, a field applied along the hard axis leads a reduction
of local orbital moment in a way to suppress the orbital order.Comment: 11 page
Pitch contours of Northern Vietnamese tones vary with focus marking
Intonation is a means of structuring discourse and one of its functions is to highlight new or contrasting information, i.e., focus. Speakers of different languages use a range of prosodic cues to mark focus. Compared to non-tonal languages such as English, tonal languages use pitch to distinguish lexical tones and focus marking. Determining the interplay between intonation and lexical tone is therefore important. Previous studies found that tonal languages use different strategies to mark focus. For example, some use an increase (e.g., Mandarin Chinese), others a decrease in pitch (e.g., Kammu). The Vietnamese language has six lexical tones and is particularly interesting for examining pitch contours in focus marking. In this article, we present a production study with 70 Northern Vietnamese speakers. Participants read six sentences aloud under two different conditions (narrow/wide focus). In each sentence, focus marked a single noun (‘focus item’) which occurred in the final position of the sentence and carried one of the six tones. Acoustic analyses of the focus item showed that Vietnamese speakers realized focus with significant differences in pitch at the beginning of the word, but the strategies to increase or decrease pitch varied across tones. Our findings add important insights to the discussion about Information Structure and the role of intonation in tonal languages by analyzing the use of prosodic cues in a complex tone system. The large number of speakers in our study also adds further methodological rigor compared to other studies, which often rely on a few speakers.1 Introduction 2 Using intonation for focus marking 2.1 Focus marking with intonation in tonal languages 2.2 Using intonation to mark pragmatic functions and focus in Vietnamese 3 Method 3.1 Participants 3.3 Material 3.2 Procedure 3.3 Pitch Analysis 4 Results 5 Discussio
Pitch contours of Northern Vietnamese tones vary with focus marking
Intonation is a means of structuring discourse and one of its functions is to highlight new or contrasting information, i.e., focus. Speakers of different languages use a range of prosodic cues to mark focus. Compared to non-tonal languages such as English, tonal languages use pitch to distinguish lexical tones and focus marking. Determining the interplay between intonation and lexical tone is therefore important. Previous studies found that tonal languages use different strategies to mark focus. For example, some use an increase (e.g., Mandarin Chinese), others a decrease in pitch (e.g., Kammu). The Vietnamese language has six lexical tones and is particularly interesting for examining pitch contours in focus marking. In this article, we present a production study with 70 Northern Vietnamese speakers. Participants read six sentences aloud under two different conditions (narrow/wide focus). In each sentence, focus marked a single noun (‘focus item’) which occurred in the final position of the sentence and carried one of the six tones. Acoustic analyses of the focus item showed that Vietnamese speakers realized focus with significant differences in pitch at the beginning of the word, but the strategies to increase or decrease pitch varied across tones. Our findings add important insights to the discussion about Information Structure and the role of intonation in tonal languages by analyzing the use of prosodic cues in a complex tone system. The large number of speakers in our study also adds further methodological rigor compared to other studies, which often rely on a few speakers
New perspectives for eye-sparing treatment strategies in primary uveal melanoma
Uveal melanoma is the most common intraocular malignancy and arises from melanocytes in the choroid, ciliary body, or iris. The current eye-sparing treatment options include surgical treatment, plaque brachytherapy, proton beam radiotherapy, stereotactic photon radiotherapy, or photodynamic therapy. However, the efficacy of these methods is still unsatisfactory. This article reviews several possible new treatment options and their potential advantages in treating localized uveal melanoma. These methods may be based on the physical destruction of the cancerous cells by applying ultrasounds. Two examples of such an approach are High-Intensity Focused Ultrasound (HIFU)—a promising technology of thermal destruction of solid tumors located deep under the skin and sonodynamic therapy (SDT) that induces reactive oxygen species. Another approach may be based on improving the penetration of anti-cancer agents into UM cells. The most promising technologies from this group are based on enhancing drug delivery by applying electric current. One such approach is called transcorneal iontophoresis and has already been shown to increase the local concentration of several different therapeutics. Another technique, electrically enhanced chemotherapy, may promote drug delivery from the intercellular space to cells. Finally, new advanced nanoparticles are developed to combine diagnostic imaging and therapy (i.e., theranostics). However, development. these methods More are mostly advanced at an and early targeted stage of preclinical development. studies More and advanced clinical trials and targeted would be preclinical needed to studies introduce and some clinical of trials these would techniques be needed to routine to introduce clinical practice. some of these techniques to routine clinical practice
Learning radiation oncology in Europe: Results of the ESTRO multidisciplinary survey
Introduction: Radiotherapy education can be very different across Europe, despite the publication of the ESTRO core curricula in 2011. The purpose of the current study is to map the different RO European education systems, to report their perceived quality and to understand what could be improved to better teach RO. Methods: An online survey consisting of 30 questions was sent to RO professionals under 40 years of age via email and social media. Clinicians, radiobiologists, physicists and radiation therapists (RTTs) were invited to answer questions regarding (1) demographics data, (2) duration, (3) organization, (4) content, (5) quality and potential improvements of national education programs. Results: Four hundred and sixty three questionnaires were received from 34 European countries. All disciplines were represented: 45% clinicians (n = 210), 29% physicists (n = 135), 24% RTTs (n = 108) and 2% radiobiologists (n = 10). Male and female participants were well-balanced in each speciality, except for radiobiologists (80% males). Median age was 31.5 years old (range 21–40). A large range of the duration of the National RO education programs was observed: median = 9 years (range: 3–15). In half of the surveyed countries the European Credit Transfer System (ECTS), that facilitates mobility for trainees, has been implemented. Participants declared only a minority of countries have implemented the ESTRO Core Curriculum (n = 5). A quarter of participants indicated that their national education program is insufficient. Conclusion: This is the first study to examine the different RO education systems in Europe. Large differences in organization and duration of national education programs have been found, along with perceived quality across Europe within each speciality. These results show the necessity of a discussion on how to move forward in this diversity of education programs and the potential contribution that the ESTRO may fulfil
Evidence for short range orbital order in paramagnetic insulating (Al,V)_2O_3
The local structure of (Al_0.06V_0.94)_2O_3 in the paramagnetic insulating
(PI) and antiferromagnetically ordered insulating (AFI) phase has been
investigated using hard and soft x-ray absorption techniques. It is shown that:
1) on a local scale, the symmetry of the vanadium sites in both the PI and the
AFI phase is the same; and 2) the vanadium 3d - oxygen 2p hybridization, as
gauged by the oxygen 1s absorption edge, is the same for both phases, but
distinctly different from the paramagnetic metallic phase of pure V_2O_3. These
findings can be understood in the context of a recently proposed model which
relates the long range monoclinic distortion of the antiferromagnetically
ordered state to orbital ordering, if orbital short range order in the PI phase
is assumed. The measured anisotropy of the x-ray absorption spectra is
discussed in relation to spin-polarized density functional calculations.Comment: 8 pages, 5 figure
Almost uniform sampling via quantum walks
Many classical randomized algorithms (e.g., approximation algorithms for
#P-complete problems) utilize the following random walk algorithm for {\em
almost uniform sampling} from a state space of cardinality : run a
symmetric ergodic Markov chain on for long enough to obtain a random
state from within total variation distance of the uniform
distribution over . The running time of this algorithm, the so-called {\em
mixing time} of , is , where
is the spectral gap of .
We present a natural quantum version of this algorithm based on repeated
measurements of the {\em quantum walk} . We show that it
samples almost uniformly from with logarithmic dependence on
just as the classical walk does; previously, no such
quantum walk algorithm was known. We then outline a framework for analyzing its
running time and formulate two plausible conjectures which together would imply
that it runs in time when is
the standard transition matrix of a constant-degree graph. We prove each
conjecture for a subclass of Cayley graphs.Comment: 13 pages; v2 added NSF grant info; v3 incorporated feedbac
Mutual Exclusion Statistics in Exactly Solvable Models in One and Higher Dimensions at Low Temperatures
We study statistical characterization of the many-body states in exactly
solvable models with internal degrees of freedom. The models under
consideration include the isotropic and anisotropic Heisenberg spin chain, the
Hubbard chain, and a model in higher dimensions which exhibits the Mott
metal-insulator transition. It is shown that the ground state of these systems
is all described by that of a generalized ideal gas of particles (called
exclusons) which have mutual exclusion statistics, either between different
rapidities or between different species. For the Bethe ansatz solvable models,
the low temperature properties are well described by the excluson description
if the degeneracies due to string solutions with complex rapidities are taken
into account correctly. {For} the Hubbard chain with strong but finite
coupling, charge-spin separation is shown for thermodynamics at low
temperatures. Moreover, we present an exactly solvable model in arbitrary
dimensions which, in addition to giving a perspective view of spin-charge
separation, constitutes an explicit example of mutual exclusion statistics in
more than two dimensions
Veiled Muslim women’s responses to experiences of gendered Islamophobia in the UK
In a post-9/11 climate, Islamophobia has increased significantly in the UK and elsewhere in the West. ISIS-inspired terrorist attacks in the UK as well as in France, Belgium, Germany and more recently in Sri Lanka have triggered an increase in verbal and physical attacks against Muslims. Drawing on intersectionality (as a nexus of identities that work together to render certain individuals as ‘ideal’ targets to attack), veiled Muslim women are likely to experience gendered Islamophobia in the cyber world but also in ‘real’ life due to the intersections between their ‘visible’ Muslim identity and gender performance. In the British context, although Islamophobia is recorded as a hate crime nationally, and misogyny is recorded as a hate crime locally in some police forces, veiled Muslim women are unlikely to report their experiences to the police. Drawing on qualitative interviews with Muslim women who wear the niqab (face veil), the purpose of this paper is to examine the ways in which they respond to experiences of gendered Islamophobia as well as their reasons for not reporting their experiences to the police
- …