Modal clustering asymptotics with applications to bandwidth selection

Density-based clustering relies on the idea of linking groups to some specific features of the probability distribution underlying the data. The reference to a true, yet unknown, population structure allows to frame the clustering problem in a standard inferential setting, where the concept of ideal population clustering is defined as the partition induced by the true density function. The nonparametric formulation of this approach, known as modal clustering, draws a correspondence between the groups and the domains of attraction of the density modes. Operationally, a nonparametric density estimate is required and a proper selection of the amount of smoothing, governing the shape of the density and hence possibly the modal structure, is crucial to identify the final partition. In this work, we address the issue of density estimation for modal clustering from an asymptotic perspective. A natural and easy to interpret metric to measure the distance between density-based partitions is discussed, its asymptotic approximation explored, and employed to study the problem of bandwidth selection for nonparametric modal clustering

Doping Evolution of Magnetic Order and Magnetic Excitations in (Sr1−x_{1-x}Lax_x)3_3Ir2_2O7_7

We use resonant elastic and inelastic X-ray scattering at the Ir-$L_3$ edge to study the doping-dependent magnetic order, magnetic excitations and spin-orbit excitons in the electron-doped bilayer iridate (Sr$_{1-x}$La$_{x}$)$_3$Ir$_2$O$_7$ ($0 \leq x \leq 0.065$). With increasing doping $x$, the three-dimensional long range antiferromagnetic order is gradually suppressed and evolves into a three-dimensional short range order from $x = 0$ to $0.05$, followed by a transition to two-dimensional short range order between $x = 0.05$ and $0.065$. Following the evolution of the antiferromagnetic order, the magnetic excitations undergo damping, anisotropic softening and gap collapse, accompanied by weakly doping-dependent spin-orbit excitons. Therefore, we conclude that electron doping suppresses the magnetic anisotropy and interlayer couplings and drives (Sr$_{1-x}$La$_x$)$_3$Ir$_2$O$_7$ into a correlated metallic state hosting two-dimensional short range antiferromagnetic order and strong antiferromagnetic fluctuations of $J_{\text{eff}} = \frac{1}{2}$ moments, with the magnon gap strongly suppressed.Comment: 6 Pages, 3 Figures, with supplementary in Sourc

Equilibrium tuned by a magnetic field in phase separated manganite

We present magnetic and transport measurements on La5/8-yPryCa3/8MnO3 with y = 0.3, a manganite compound exhibiting intrinsic multiphase coexistence of sub-micrometric ferromagnetic and antiferromagnetic charge ordered regions. Time relaxation effects between 60 and 120K, and the obtained magnetic and resistive viscosities, unveils the dynamic nature of the phase separated state. An experimental procedure based on the derivative of the time relaxation after the application and removal of a magnetic field enables the determination of the otherwise unreachable equilibrium state of the phase separated system. With this procedure the equilibrium phase fraction for zero field as a function of temperature is obtained. The presented results allow a correlation between the distance of the system to the equilibrium state and its relaxation behavior.Comment: 13 pages, 5 figures. Submited to Journal of Physics: Condensed Matte

Effect of Cueing on Learning Transfer Among Pre-professional Undergraduate Healthcare Students Engaged in a Case-based Analogical Reasoning Exercise

To examine the extent of transfer of cued versus non-cued pre- professional healthcare undergraduates engaged in a case-based analogical reasoning exercise. Independent t-test analysis and effect size was calculated to assess transfer between cued and non-cued participants (N = 192). Cued participants (n = 98, M = 2.30, SD = .89) demonstrated significantly more transfer (t (175.91) = 2.65; p = .009; CI95 = (.10, 0.68); d = .39) than non-cued participants (n = 94, M = 1.9, SD = 1.14). Learning transfer improves among pre- professional undergraduates when cued during a case-based analogical reasoning experience

Resonant inelastic x-ray scattering study of charge excitations in La2CuO4

We report a resonant inelastic x-ray scattering study of the dispersion relations of charge transfer excitations in insulating La$_2$CuO$_4$. These data reveal two peaks, both of which show two-dimensional characteristics. The lowest energy excitation has a gap energy of $\sim 2.2$ eV at the zone center, and a dispersion of $\sim 1$ eV. The spectral weight of this mode becomes dramatically smaller around ($\pi$, $\pi$). The second peak shows a smaller dispersion ($\sim 0.5$ eV) with a zone-center energy of $\sim 3.9$ eV. We argue that these are both highly dispersive exciton modes damped by the presence of the electron-hole continuum.Comment: 5 pages, 3 figure

Resonant inelastic x-ray scattering study of holon-antiholon continuum in SrCuO2

We report a resonant inelastic x-ray scattering study of charge excitations in the quasi-one-dimensional Mott insulator SrCuO2. We observe a continuum of low-energy excitations, in which a highly dispersive feature with a large sinusoidal dispersion (~1.1 eV) resides. We have also measured the optical conductivity, and studied the dynamic response of the extended Hubbard model with realistic parameters, using a dynamical density-matrix renormalization group method. In contrast to earlier work, we do not find a long-lived exciton, but rather these results suggest that the excitation spectrum comprises a holon-antiholon continuum together with a broad resonance.Comment: Final version to be published in Phys. Rev. Let

The Prevalence of Secondary School Sport Safety Policies within State Athletic Associations and Legislation

Purpose: The location of secondary school health and safety policies impacts how they are implemented by the sports medicine team and stakeholders. Yet, a comprehensive list of each state’s policy locations has not been established. The purpose of this study was to describe where secondary school health and safety policies were located at the state level within the United States. Method: Emergency related health and safety policies were designated as either being located in the state high school athletics association (SHSAA), state legislation (LEGIS), or in both SHSAA and LEGIS (BOTH). Designation was determined by two researchers who independently reviewed each individual policy. Frequencies were tabulated for the leading causes of catastrophic injury (exertional heat stroke (EHS), traumatic head injuries (THI), sudden cardiac arrest (SCA), and emergency preparedness (EP)) for the distribution of policies emanating from SHSSA, LEGIS or BOTH. Prevalence ratios (PRs) with 95% confidence intervals (CIs) were calculated between the policies categories and location. Results: Most (99.35%) EHS and EP (83.02%) policies were found in SHSAA. Whereas the majority (79.70%) of SCA policies were found in LEGIS. Traumatic head injuries were most frequently observed in SHSAA, however, had the greatest distribution across all three categories (SHSAA=45.31%, LEGIS=25.52%, BOTH = 29.16%). The category that most frequently found policies in BOTH was THI (THI= 29.16%, all others =2.25%; PR=12.96; 95% CI=7.81, 21.53). Conclusions: Emergency related health and safety policies for secondary school sports are commonly found in SHSAA. TBI and SCA are also found in LEGIS. This demonstrates great variability of policy locations

Estudio sobre la prevalencia del burnout en los médicos del Área Sanitaria de Talavera de la Reina

ObjetivoDeterminar el grado de burnout, o desgaste profesional, en los médicos del Área Sanitaria de Talavera de la Reina y los factores asociadosDiseñoEstudio descriptivo transversalSujetosMédicos dedicados a la atención primaria (AP) (n = 106) y atención especializada (AE) (n = 129)MedicionesCuestionario Maslach Burnout Inventory (MBI) y encuesta con variables sociodemográficas y sugerencias. Ambos anónimos y autoadministrablesResultadosContestaron 144 médicos (61,27%), 63 de AP y 81 de AE, varones el 72,2% y con una media de edad de 45 años (con una escasa variabilidad entre AP y AE). La media de años trabajados fue de 18,65. Realizan guardias 102 (70,83%). El tipo de contrato es fijo en 85 (59,02%), interino en 49 (34,02%) y "otros" en 10(6,94%). Presenta burnout el 76,4% de los profesionales (moderado en el 38,9% y alto en el 37,5%). Resulta estadísticamente significativa la diferencia entre burnout de AP y AE (el 85,7 frente al 69,1%). En el resto de las variables estudiadas edad, sexo, estado civil, realización de guardias no encontramos diferencias significativas. Como sugerencias para mitigar el burnout destacan la petición de apoyo de mejoras laborales, un mayor reconocimiento personal y profesional, la implicación de la Administración y la Gerencia, la remuneración económica, facilitar formación e investigación, etcConclusiones.El grado de desgaste profesional (burnout) es muy elevado en nuestra área, con un mayor porcentaje en AP que en AEObjectiveTo determine the degree of burnout or professional wear-and-tear in doctors from the Talavera de la Reina Health Area and linked factorsDesignTransversal, descriptive studyParticipantsDoctors in primary care (PC)(n=106) and specialist care (SC) (n=129)Measurements and ResultsMaslach Burnout Inventory (MBI) questionnaire and a survey with social and demographic variables and suggestions. Both were anonymous and self-administeredResults144 (61.27%) answered, 63 from PC and 81 SC. 72.2% were male, with a meanage of 45 (with little variability between PC and SC). Average years worked were 18.65.102 (70.83%) worked cover. 85 (59.02%) had an indefinite contract, 49 (34.02%) a temporary one, and 10 (6.94%) other kinds.76.4% of the professionals suffered burnout(moderate in 38.9% and high in 37.5%). The difference between PC and SC burnout(85.7% vs 69.1%) was statistically significant.In the remaining variables studied (age, sex, marital status, working of cover shifts…) we found no significant differences. Among suggestions to mitigate burnout were demands to support improvements in working conditions, greater personal and professional recognition, involvement of the government and management, economic remuneration,providing more training and research, etcConclusionsProfessional wear-and-tear or burnout is very high in our area, and is higher in PC than in S