Development, women-centricity and psychometric properties of maternity patient-reported outcome measures (PROMs): A systematic review.

BACKGROUND: Measuring maternity care outcomes based on what women value is critical to promoting woman-centred maternity care. Patient-reported outcome measures (PROMs) are instruments that enable service users to assess healthcare service and system performance. AIM: To identify and critically appraise the risk of bias, woman-centricity (content validity) and psychometric properties of maternity PROMs published in the scientific literature. METHODS: MEDLINE, CINAHL Plus, PsycINFO and Embase were systematically searched for relevant records between 01/01/2010 and 07/10/2021. Included articles underwent risk of bias, content validity and psychometric properties assessments in line with COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) guidance. PROM results were summarised according to language subgroups and an overall recommendation for use was determined. FINDINGS: Forty-four studies reported on the development and psychometric evaluation of 9 maternity PROMs, grouped into 32 language subgroups. Risk of bias assessments for the PROM development and content validity showed inadequate or doubtful methodological quality. Internal consistency reliability, hypothesis testing (for construct validity), structural validity and test-retest reliability varied markedly in sufficiency and evidence quality. No PROMs received a level 'A' recommendation, required for real-world use. CONCLUSION: Maternity PROMs identified in this systematic review had poor quality evidence for their measurement properties and lacked sufficient content validity, indicating a lack of woman-centricity in instrument development. Future research should prioritise women's voices in deciding what is relevant, comprehensive and comprehensible to measure, as this will impact overall validity and reliability and facilitate real-world use.

The gapless energy spectrum and spin-Peierls instability of 1D Heisenberg spin systems in polymeric complexes of transition metals and hypothetical carbon allotropes.

We investigate the spin-Peierls instability of some periodic 1D Heisenberg spin systems having a gapless energy spectrum at different values of coupling J between the unit cells. Using the density-matrix renormalization group method we numerically study the dependence of critical exponents p  of spin-Peierls transition of above spin systems on the value of J. In contrast to chain systems, we find significantly non-monotonous dependence p (J) for three-legs ladder system. In the limit of weak coupling J we derive effective spin s chain Hamiltonians describing the low-energy states of the system considered by means of perturbation theory. The value of site spin s coincides with the value of the ground-state spin of the isolated unit cell of the system considered. This means that at small J values all the systems with the singlet ground state and the same half-integer value of s should have a similar critical behavior which is in agreement with our numerical study. The presence of gapped excitations inside the unit cells at small values of J should give, for our spin systems, at least one intermediate plateau in field dependence of magnetization at low temperatures. The stability of this plateau against the increase of the values of J and temperature is studied using the quantum Monte-Carlo method.

Area law scaling for the entropy of disordered quasifree fermions.

We study theoretically and numerically the entanglement entropy of the d-dimensional free fermions whose one-body Hamiltonian is the Anderson model. Using the basic facts of the exponential Anderson localization, we show first that the disorder averaged entanglement entropy ⟨S(Λ)⟩ of the d dimension cube Λ of side length l admits the area law scaling ⟨S(Λ)⟩ ∼ l((d-1)),l ≫ 1, even in the gapless case, thereby manifesting the area law in the mean for our model. For d = 1 and l ≫ 1 we obtain then asymptotic bounds for the entanglement entropy of typical realizations of disorder and use them to show that the entanglement entropy is not self-averaging, i.e., has nonvanishing random fluctuations even if l ≫ 1.

Simulation and visualization of topological defects in nematic liquid crystals.

We present a method of visualizing topological defects arising in numerical simulations of liquid crystals. The method is based on scientific visualization techniques developed to visualize second-rank tensor fields, yielding information not only on the local structure of the field but also on the continuity of these structures. We show how these techniques can be used to first locate topological defects in fluid simulations of nematic liquid crystals where the locations are not known a priori and then study the properties of these defects including the core structure. We apply these techniques to simulation data obtained by previous authors who studied a rapid quench and subsequent equilibration of a Gay-Berne nematic. The quench produces a large number of disclination loops which we locate and track with the visualization methods. We show that the cores of the disclination lines have a biaxial region and the loops themselves are of a hybrid wedge-twist variety.