Electronic states associated with a chain of magnetic adatoms on the surface of an ordinary s-wave superconductor have been shown theoretically to form a one-dimensional (1D) topological phase with ...unpaired Majorana fermions bound to its ends. In a simple 1D effective model the system exhibits an interesting self-organization property: The pitch of the spiral formed by the adatom magnetic moments tends to adjust itself so that electronically the chain remains in the topological phase whenever such a state is physically accessible. Here we examine the physics underlying this self-organization property in the framework of a more realistic two-dimensional model of a superconducting surface coupled to a 1D chain of magnetic adatoms. Treating both the superconducting order and the magnetic moments self-consistently, we find that the system retains its self-organization property, even if the topological phase extends over a somewhat smaller portion of the phase diagram compared to the 1D model. We also study the effect of imperfections and find that, once established, the topological phase survives moderate levels of disorder.
Clinicians, researchers, and global health advocates often include pubertal development in outcomes. However, assessments of pubertal stage can be challenging because of the sensitive nature and ...feasibility of clinical examinations, especially in larger settings.
To determine the accuracy of self-assessed Tanner staging when compared with physically assessed Tanner stages by a clinician.
MEDLINE, PubMed, Embase, Web of Science, Scopus, the Cochrane Library, CINAHL.
Studies were included if they reported 5 × 5 tables of self-assessment compared to clinician-assessment for the 5-stage Tanner scale.
We extracted data to generate complete 5 × 5 tables for each study, including any subgroup eligible for the analysis, such as overweight/obese youth.
After screening, 22 studies representing 21,801 participants met our inclusion criteria for the meta-analysis. Overall agreement was moderate or substantial between the 2 assessments, with breast stage 1, female pubic hair 1, male pubic hair 1, and male pubic hair 5 having the highest agreement. When stages were collapsed into pre- (Tanner stage 1), in (stages 2,3), and completing (stages 4,5) puberty, levels of agreement improved, especially for pre- and completing pubertal development. Most included studies comprised Caucasian youth. More studies are needed which include a broader range of geographic and socioeconomic settings, as well as a greater diversity of racial/ethnic groups.
Self-assessment of puberty is most accurate when identifying Tanner stage 1, Tanner stage 5 and when development is categorized into prepuberty, in, and completing puberty phases. Use of self-assessment data should be structured accordingly.
PROSPERO # CRD42018100205.
We study a single polaron in the Su-Schrieffer-Heeger (SSH) model using four different techniques (three numerical and one analytical). Polarons show a smooth crossover from weak to strong coupling, ...as a function of the electron-phonon coupling strength λ, in all models where this coupling depends only on phonon momentum q. In the SSH model the coupling also depends on the electron momentum k; we find it has a sharp transition, at a critical coupling strength λ(c), between states with zero and nonzero momentum of the ground state. All other properties of the polaron are also singular at λ=λ(c). This result is representative of all polarons with coupling depending on k and q, and will have important experimental consequences (e.g., in angle-resolved photoemission spectroscopy and conductivity experiments).
Discovering the low-energy conformations of a molecule is of great interest to computational chemists, with applications in in silico materials design and drug discovery. In this paper, we propose a ...variable neighbourhood search heuristic for the conformational search problem. Using the structure of a molecule, neighbourhoods are chosen to allow for the efficient use of a binary quadratic optimizer for conformational search. The method is flexible with respect to the choice of molecular force field and the number of discretization levels in the search space, and can be further generalized to take advantage of higher-order binary polynomial optimizers. It is well-suited for the use of devices such as quantum annealers. After carefully defining neighbourhoods, the method easily adapts to the size and topology of these devices, allowing for seamless scaling alongside their future improvements.
Previous work suggests that π–π interactions between certain solutes and both phenyl and cyano columns can contribute to sample retention and the selectivity of these two column types versus ...alkylsilica columns. Recent studies also suggest that dipole–dipole interactions are generally unimportant for retention on cyano columns. The present study presents data for 44 solutes, three columns and two different mobile phases that were selected to further test these conclusions. We find that π–π interactions can contribute to retention on both cyano and phenyl columns, while dipole–dipole interactions are likely to be significant for the retention of polar aliphatic solutes on cyano columns. When acetonitrile/water mobile phases are used, both π–π and dipole–dipole interactions are suppressed, compared to the use of methanol/water.
The previous decade has seen an abundance of scholarship on the benefits of critical consciousness (CC) for racial and ethnic minority youth. However, it is unclear whether CC is a buffer against the ...negative effects of racial discrimination on Black adolescents' outcomes. The present study examined whether three CC dimensions buffered against the negative effects of racial discrimination on academic attitudes.
A total of 205 Black adolescents (
= 15.10) reported racial discrimination and CC. We conducted multiple regression analyses for each component of CC to test for their direct and protective effects on academic attitudes.
Our results revealed associations between CC dimensions and academic attitudes. Critical reflection and critical action also buffered against racial discrimination's negative effects.
Implications for research on the nature and impact of CC dimensions on racial discrimination and academic attitudes are discussed. (PsycInfo Database Record (c) 2023 APA, all rights reserved).
Microfiltration (MF) is a well-known process that can be used in the dairy industry to separate caseins from serum proteins (SP) in skim milk using membranes with a pore diameter of 0.1μm. Graded ...permeability ceramic membranes have been studied widely as means of improving milk fractionation by overcoming problems encountered with other MF membranes. The ideal operating parameters for process efficiency in terms of membrane selectivity, permeate flux, casein loss, SP transmission, energy consumption, and dilution with water remain to be determined for this membrane. Our objective was to evaluate the effects of transmembrane pressure (TMP), volumetric concentration factor (VCF), and diafiltration on overall process efficiency. Skim milk was processed using a pilot-scale MF system equipped with 0.72-m2 graded permeability membranes with a pore size of 0.1μm. In the first experiment, in full recycle mode, TMP was set at 124, 152, 179, or 207 kPa by adjusting the permeate pressure at the outlet. Whereas TMP had no significant effect on permeate and retentate composition, 152 kPa was found to be optimal for SP removal during concentration and concentration or diafiltration experiments. When VCF was increased to 3×, SP rejection coefficient increased along with energy consumption and total casein loss, whereas SP removal rate decreased. Diafiltering twice allowed an increase in total SP removal but resulted in a substantial increase in energy consumption and casein loss. It also reduced the SP removal rate by diluting permeate. The membrane surface area required for producing cheese milk by blending whole milk, cream, and MF retentate (at different VCF) was estimated for different cheese milk casein concentrations. For a given casein concentration, the same quantity of permeate and SP would be produced, but less membrane surface area would be needed at a lower retentate VCF. Microfiltration has great potential as a process of adding value to conventional cheesemaking processes, but its cost-effectiveness at a large scale remains to be demonstrated.
Measuring DVCS on a neutron target is a necessary step to deepen our understanding of the structure of the nucleon in terms of Generalized Parton Distributions (GPDs). The combination of DVCS ...observables on neutron and proton targets allows to perform a flavor decomposition of the Compton Form Factors (CFFs), which are related to integrals of GPDs. Moreover, neutron-DVCS plays a complementary role to DVCS on a transversely polarized proton target in the determination of the CFF of the GPD
E
, the least known and constrained GPD that enters Ji’s angular momentum sum rule. A measurement of the beam-charge asymmetry (BCA) in the
e
±
d
→
e
±
n
γ
(
p
)
reaction can significantly impact the experimental determination of the real CFFs of the
E
and, to a lesser extent,
H
~
CFFs.
Double Deeply Virtual Compton Scattering (DDVCS) is the only experimental channel for the determination of the dependence of the Generalized Parton Distributions (GPDs) on both the average and the ...transferred momentum independently. The physics observables of the electron induced di-muon production reaction
e
→
±
p
→
e
±
p
μ
+
μ
-
off unpolarized hydrogen are discussed. Their measurement with the high luminosity and large acceptance SoLID spectrometer at the Thomas Jefferson National Accelerator Facility, using polarized and unpolarized positron and electron beams at 11 GeV is investigated. This experimental configuration is shown to provide unprecedented access to the GPDs with the determination of the real and imaginary parts of the Compton Form Factor
H
in an unexplored phase space, and to enable an exploratory investigation of higher twist effects.
The precision of experimental data and analysis techniques is a key feature of any discovery attempt. A striking example is the proton radius puzzle where the accuracy of the spectroscopy of muonic ...atoms challenges traditional electron scattering measurements. The present work proposes a novel method for the determination of spatial moments from densities expressed in the momentum space. This method provides a direct access to even, odd, and more generally any real, negative and positive moment with order larger than −3. As an illustration, the application of this method to the electric form factor of the proton is discussed in detail.
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