Identifying Gender and Racial Bias in Pediatric Fellowship Letters of Recommendation: Do Word Choices Influence Interview Decisions?

OBJECTIVES

To describe linguistic differences in letters of recommendation (LORs) for pediatric fellowship candidates based on applicant and letter writer demographics and to examine if these differences influenced the decision to interview a candidate for a fellowship position.

STUDY DESIGN

LORs for applicants to 8 pediatric subspecialty fellowships at a single academic center from the 2020 Match were analyzed in this cross-sectional study. Frequency of validated agentic and communal terms in each letter were determined by a language processing web application. Bias was determined as having a >5% surplus of agentic or communal terms.

RESULTS

We analyzed 1521 LORs from 409 applicants: 69% were women, 28% were under-represented minorities in medicine (URM), and 50% were invited to interview. Overall, 66% of LORs were agentic biased, 16% communal biased, and 19% neutral. There was no difference in bias in LORs by an applicant's gender (woman 67% agentic vs man 62% agentic; P = .058), race, or ethnicity (non-URM 65% agentic vs URM 67% agentic; P = .660). Despite a lower frequency of agentic terms in LORs for applicants invited for interviews, when accounting for other components of an application and applicant demographics, no significant association was made between language bias in LORs and fellowship interview status.

CONCLUSIONS

The frequency of agentic and communal terms in LORs for pediatric subspecialty fellowship candidates were not found to influence the decision to invite a candidate to interview. However, raising awareness of potential areas of bias within the pediatric fellowship selection process might lead to a more equitable and holistic approach to application review.

Feedback Culture Perceived by Trainees in an Academic Institution: A Mixed Methods Study

OBJECTIVES

Lack of a well-functioning institutional feedback culture can undermine acquisition of skills essential for high quality patient care. The objective of this study was to assess feedback culture perceived by resident and fellow trainees, utilizing a mixed methods design.

METHODS

Pediatric fellows and residents completed an anonymous feedback environment survey consisting of 7 constructs: source credibility, feedback quality, feedback delivery, reinforcing feedback, constructive feedback, source availability, and promotion of feedback seeking, using a 7-point Likert scale. Trainee ratings were compared using two-sided Fisher's exact tests. Multivariable analyses used a linear regression model. For the qualitative study, semistructured interviews of residents were conducted. The constant comparative method was used to incrementally code, categorize data, and derive themes.

RESULTS

Fifty-two residents and 21 fellows completed the survey (response rates 65% and 47%, respectively). Scores were more favorable for fellows compared with residents in 6 of 7 feedback constructs (P < .05), including on multivariate analysis. Hispanic ethnicity and female gender were associated with lower scores on source credibility (P = .04) and constructive feedback (P = .03), respectively. Two qualitative themes were identified: expectation of efficiency in patient care compromises the quality and quantity of feedback, and a culture that prioritizes courtesy over candor negatively impacts feedback quality. These themes were more pronounced when residents worked with pediatric subspecialists compared with hospitalists.

CONCLUSIONS

We described the feedback culture, which was less favorable in the residency program. The need for efficient patient care and a culture of courtesy adversely impacted the quality of feedback, especially among subspecialists.

Words Used in Letters of Recommendation for Pediatric Residency Applicants: Demographic Differences and Impact on Interviews

OBJECTIVE

To describe differences in agentic (achievement) and communal (relationship) terms in letters of recommendation (LORs) for pediatric residency candidates by applicant and letter writer demographics and to examine if LOR language is associated with interview status.

METHODS

A random sample of applicant profiles and LORs submitted to one institution were analyzed from the 2020-21 Match. Letters of recommendation text was inputted into a customized natural language processing application which determined the frequency of agentic and communal words in each LOR. Neutral LORs were defined as having< 5% surplus of agentic or communal terms.

RESULTS

We analyzed 2094 LORs from 573 applicants: 78% were women, 24% were under-represented in medicine (URiM), and 39% were invited to interview. Most letter writers were women (55%) and of senior academic rank (49%). Overall, 53% of LORs were agency biased, 25% communal biased, and 23% neutral. There was no difference in agency and communally biased LORs by an applicant's gender (men 53% agentic vs women 53% agentic, P = .424), race or ethnicity (non-URiM 53% agentic vs URiM 51% agentic, P = .631). Male letter writers used significantly more agentic terms (8.5%) compared to women (6.7% agentic) or writers of both genders (3.1% communal) (P = .008). Applicants invited to interview were more likely to have a neutral LOR; however, no significant association existed between language and interview status.

CONCLUSIONS

No significant differences in language were found by applicant gender or race among pediatric residency candidates. Identifying potential biases within pediatric residency selection processes is important in creating an equitable approach to application review.

Management Practices for Standard-Risk and High-Risk Patients With Bronchiolitis

OBJECTIVE

Management guidelines for bronchiolitis advocate for supportive care and exclude those with high-risk conditions. We aim to describe and compare the management of standard-risk and high-risk patients with bronchiolitis.

METHODS

This retrospective study examined patients <2 years of age admitted to the general pediatric ward with an International Classification of Diseases, 10th Revision discharge diagnosis code of bronchiolitis or viral syndrome with evidence of lower respiratory tract involvement. Patients were defined as either standard- or high-risk on the basis of previously published criteria. The frequencies of diagnostic and therapeutic interventions were compared.

RESULTS

We included 265 patients in this study (122 standard-risk [46.0%], 143 high-risk [54.0%]). Increased bronchodilator use was observed in the standard-risk group (any albuterol dosing, standard-risk 65.6%, high-risk 44.1%, P = .003). Increased steroid use was observed in the standard-risk group (any steroid dosing, standard-risk 19.7%, high-risk 14.7%, P = .018). Multiple logistic regression revealed >3 doses of albuterol, hypertonic saline, and chest physiotherapy use to be associated with rapid response team activation (odds ratio [OR] >3 doses albuterol: 8.36 [95% confidence interval (CI): 1.99-35.10], P = .048; OR >3 doses hypertonic saline: 13.94 [95% CI: 4.32-44.92], P = .001); OR percussion and postural drainage: 5.06 [95% CI: 1.88-13.63], P = .017).

CONCLUSIONS

A varied approach to the management of bronchiolitis in both standard-risk and high-risk children occurred institutionally. Bronchodilators and steroids continue to be used frequently despite practice recommendations and regardless of risk status. More research is needed on management strategies in patients at high-risk for severe disease.

Active and passive defects in tetragonal tungsten bronze relaxor ferroelectrics

Tetragonal tungsten bronze (TTB) based oxides constitute a large family of dielectric materials which are known to exhibit complex distortions producing incommensurately modulated superstructures as well as significant local deviations from their average symmetry. The local deviations produce diffuse scattering in diffraction experiments. The structure as well as the charge dynamics of these materials are anticipated to be sensitive to defects, such as cation or oxygen vacancies. In this work, in an effort to understand how the structural and charge dynamical properties respond to these two types of vacancy defects, we have performed measurements of dielectric susceptibilities and single crystal diffraction experiments of two types of TTB materials with both 'filled' (Ba₂NdFeNb₄O₁₅and Ba₂PrFeNb₄O₁₅) and 'unfilled' (Sr_0.5Ba_0.5Nb₂O₆) cation sublattices. We also perform these measurements before and after oxygen annealing, which alters the oxygen vacancy concentrations. Surprisingly, we find that many of the diffuse scattering features that are present in the unfilled structure are also present in the filled structure, suggesting that the random fields and disorder that are characteristic of the unfilled structure are not responsible for many of the local structural features that are reflected in the diffuse scattering. Oxygen annealing clearly affected both color and dielectric properties, consistent with a diminishment of the oxygen vacancy concentration, but had little effect on observed diffuse patterns.

Enhanced superconductivity and ferroelectric quantum criticality in plastically deformed strontium titanate

The properties of quantum materials are commonly tuned using experimental variables such as pressure, magnetic field and doping. Here we explore a different approach using irreversible, plastic deformation of single crystals. We show that compressive plastic deformation induces low-dimensional superconductivity well above the superconducting transition temperature (T_c) of undeformed SrTiO₃, with evidence of possible superconducting correlations at temperatures two orders of magnitude above the bulk T_c. The enhanced superconductivity is correlated with the appearance of self-organized dislocation structures, as revealed by diffuse neutron and X-ray scattering. We also observe deformation-induced signatures of quantum-critical ferroelectric fluctuations and inhomogeneous ferroelectric order using Raman scattering. Our results suggest that strain surrounding the self-organized dislocation structures induces local ferroelectricity and quantum-critical dynamics that strongly influence T_c, consistent with a theory of superconductivity enhanced by soft polar fluctuations. Our results demonstrate the potential of plastic deformation and dislocation engineering for the manipulation of electronic properties of quantum materials.

The Effect of Sitting Versus Standing on Family Perceptions of Family-Centered Rounds

OBJECTIVE

Previous studies reveal improved perception of time spent, as well as overall experience, for patients when their inpatient provider is seated during an encounter. With our study, we aim to establish whether family experience and perception of time is improved when a pediatric inpatient provider team sits for patient and family-centered rounds.

PATIENTS AND METHODS

From February 2017 to November 2017, 99 inpatient encounters were randomly assigned to either a sitting or standing rounding team. Mean total time spent on rounds, family perception of time spent on rounds, and overall family experience with rounds (by using top-box analysis of physician communication questions) were compared between the 2 groups.

RESULTS

Total time spent on rounds was similar between the 2 groups (14.2 minutes in the sitting group and 12.7 minutes in the standing group; P = .23), and families in general overestimated the time spent with physicians in both groups (15.9 minutes in sitting group and 14.8 minutes in the standing group; P = .45). There were no significant differences in top-box experience responses (62% in sitting and 55% in standing; P = .12).

CONCLUSIONS

Sitting during the patient and family-centered rounds encounter did not affect actual or perceived time spent during rounds. Families may have a slightly more positive experience with seated rounds, but the difference in this study did not reach a level of statistical significance.

Two-dimensional overdamped fluctuations of the soft perovskite lattice in CsPbBr3

Lead halide perovskites exhibit structural instabilities and large atomic fluctuations thought to impact their optical and thermal properties, yet detailed structural and temporal correlations of their atomic motions remain poorly understood. Here, these correlations are resolved in CsPbBr₃ crystals using momentum-resolved neutron and X-ray scattering measurements as a function of temperature, complemented with first-principles simulations. We uncover a striking network of diffuse scattering rods, arising from the liquid-like damping of low-energy Br-dominated phonons, reproduced in our simulations of the anharmonic phonon self-energy. These overdamped modes cover a continuum of wave vectors along the edges of the cubic Brillouin zone, corresponding to two-dimensional sheets of correlated rotations in real space, and could represent precursors to proposed two-dimensional polarons. Further, these motions directly impact the electronic gap edge states, linking soft anharmonic lattice dynamics and optoelectronic properties. These results provide insights into the highly unusual atomic dynamics of halide perovskites, relevant to further optimization of their optical and thermal properties.

Intertwined density waves in a metallic nickelate

Nickelates are a rich class of materials, ranging from insulating magnets to superconductors. But for stoichiometric materials, insulating behavior is the norm, as for most late transition metal oxides. Notable exceptions are the 3D perovskite LaNiO₃, an unconventional paramagnetic metal, and the layered Ruddlesden-Popper phases R₄Ni₃O₁₀, (R = La, Pr, Nd). The latter are particularly intriguing because they exhibit an unusual metal-to-metal transition. Here, we demonstrate that this transition results from an incommensurate density wave with both charge and magnetic character that lies closer in its behavior to the metallic density wave seen in chromium metal than the insulating stripes typically found in single-layer nickelates like La_2-xSr_xNiO₄. We identify these intertwined density waves as being Fermi surface-driven, revealing a novel ordering mechanism in this nickelate that reflects a coupling among charge, spin, and lattice degrees of freedom that differs not only from the single-layer materials, but from the 3D perovskites as well.

Layered Ruddlesden-Popper structure nickelates R₄Ni₃O₁₀ (R = La,Pr) show an unusual metal-to-metal transition, but its origin has remained elusive for more than two decades. Here, the authors show that this transition results from intertwined density waves that arise from a coupling between charge and spin degrees of freedom

The relation of local order to material properties in relaxor ferroelectrics

Correlating electromechanical and dielectric properties with nanometre-scale order is the defining challenge for the development of piezoelectric oxides. Current lead (Pb)-based relaxor ferroelectrics can serve as model systems with which to unravel these correlations, but the nature of the local order and its relation to material properties remains controversial. Here we employ recent advances in diffuse scattering instrumentation to investigate crystals that span the phase diagram of PbMg_1/3Nb_2/3O₃-xPbTiO₃ (PMN-xPT) and identify four forms of local order. From the compositional dependence, we resolve the coupling of each form to the dielectric and electromechanical properties observed. We show that relaxor behaviour does not correlate simply with ferroic diffuse scattering; instead, it results from a competition between local antiferroelectric correlations, seeded by chemical short-range order, and local ferroic order. The ferroic diffuse scattering is strongest where piezoelectricity is maximal and displays previously unrecognized modulations caused by anion displacements. Our observations provide new guidelines for evaluating displacive models and hence the piezoelectric properties of environmentally friendly next-generation materials.

Emergence of coherence in the charge-density wave state of 2H-NbSe2

A charge-density wave (CDW) state has a broken symmetry described by a complex order parameter with an amplitude and a phase. The conventional view, based on clean, weak-coupling systems, is that a finite amplitude and long-range phase coherence set in simultaneously at the CDW transition temperature T_cdw. Here we investigate, using photoemission, X-ray scattering and scanning tunnelling microscopy, the canonical CDW compound 2H-NbSe₂ intercalated with Mn and Co, and show that the conventional view is untenable. We find that, either at high temperature or at large intercalation, CDW order becomes short-ranged with a well-defined amplitude, which has impacts on the electronic dispersion, giving rise to an energy gap. The phase transition at T_cdw marks the onset of long-range order with global phase coherence, leading to sharp electronic excitations. Our observations emphasize the importance of phase fluctuations in strongly coupled CDW systems and provide insights into the significance of phase incoherence in ‘pseudogap’ states.

Charge density waves are described by a complex order parameter whose amplitude is expected to vanish at the transition temperature. This study shows that the transition in 2H-NbSe₂ is driven by fluctuations of the phase of the order parameter, with a finite amplitude surviving in the disordered state.

Integrating ecosystem services into risk management decisions: case study with Spanish citrus and the insecticide chlorpyrifos

The European regulatory system for the approval of pesticides includes a thorough evaluation of risks to the environment and is designed to be protective of ecosystems. However, a decision to ban an agrochemical could also potentially have a negative impact on the value of ecosystem services, if resulting changes in crop management are damaging to ecosystems or result in negative socio-economic impacts. To support regulatory decision-making, consideration of ecosystem services to identify best environmental management options could be a way forward. There is generally a growing trend for the consideration of ecosystem services in decision making. Ecosystems provide the conditions for growing food, regulate water and provide wildlife habitats; these, amongst others, are known as ecosystem services. The objectives of this case study were to bring a holistic approach to decision making by valuing the environmental, social and economic benefits derived from the use of chlorpyrifos in Valencian citrus production. Spanish growers harvest between 5 and 6 milliont of citrus annually, worth an estimated €5 to 7 billion in food markets throughout Europe. The approach highlighted the potential for unintended negative consequences of regulatory decisions if the full context is not considered. In this study, rather than a regulatory restriction, the best option was the continued use of chlorpyrifos together with vegetated conservation patches as refuges for non-target insects. The conservation patches offset potential insecticidal impacts to insects whilst maintaining citrus production, farm income and the amenity value of the citrus landscape of Valencia. This was an initial proof-of-concept study and illustrates the importance of a wider perspective; other cases may have different outcomes depending on policies, the pesticide, crop scenarios, farm economics and the region.

The utility of inpatient rebound bilirubin levels in infants readmitted after birth hospitalization for hyperbilirubinemia

BACKGROUND AND OBJECTIVES

There are few data evaluating the role of inpatient rebound bilirubin levels in the management of infants readmitted after their birth hospitalization for indirect hyperbilirubinemia. The goal of the present study was to evaluate the clinical utility of inpatient rebound bilirubin levels within this patient population.

METHODS

A retrospective cohort study was conducted of 226 infants readmitted after their birth hospitalization for indirect hyperbilirubinemia. Data from 130 infants with rebound bilirubin levels drawn at a mean of 6.1±2.4 hours after discontinuation of phototherapy were compared with data from 96 infants without rebound bilirubin levels. The primary outcome was readmission to the hospital, and secondary outcomes included length of stay and discharge time. A subgroup analysis compared characteristics of children who required repeat phototherapy versus those who did not.

RESULTS

Overall, 5 of 130 patients from the rebound group were readmitted compared with 4 of 96 patients from the no-rebound group (P=.98). Length of stay was significantly longer for patients with rebound bilirubin levels (27.7 vs 23.2 hours; P=.001). Patients with bilirubin levels lowered to ≤14 mg/dL were less likely to receive repeat phototherapy than those with levels>14 mg/dL (2 of 129 vs 12 of 97; P=.001).

CONCLUSIONS

Early inpatient rebound bilirubin levels do not successfully predict which patients will require hospital readmission for repeat phototherapy. Children with bilirubin levels lowered to ≤14 mg/dL with phototherapy are unlikely to receive repeat phototherapy.

Q-dependence of the spin fluctuations in the intermediate valence compound CePd3

We report inelastic neutron scattering experiments on a single crystal of the intermediate valence compound CePd3. At 300 K the magnetic scattering is quasielastic, with half-width Γ = 23 meV, and is independent of momentum transfer Q. At low temperature, the Q-averaged magnetic spectrum is inelastic, exhibiting a broad peak centered near Emax = 55 meV. These results, together with the temperature dependence of the susceptibility, 4f occupation number, and specific heat, can be fit by the Kondo/Anderson impurity model. The low temperature scattering near Emax, however, shows significant variations with Q, reflecting the coherence of the 4f lattice. The intensity is maximal at (1/2, 1/2, 0), intermediate at (1/2, 0, 0) and (0, 0, 0), and weak at (1/2, 1/2, 1/2). We discuss this Q-dependence in terms of current ideas about coherence in heavy fermion systems.

Electron-phonon coupling in the conventional superconductor YNi2B2C at high phonon energies studied by time-of-flight neutron spectroscopy

We report an inelastic neutron scattering investigation of phonons with energies up to 159 meV in the conventional superconductor YNi(2)B(2)C. Using the sweep mode, a newly developed time-of-flight technique involving the continuous rotation of a single crystal specimen, allowed us to measure a four-dimensional volume in (Q, E) space and, thus, determine the dispersion surface and linewidths of the A(1g) (≈102 meV) and A(u) (≈159 meV) type phonon modes over the whole Brillouin zone. Despite of having linewidths of Γ=10 meV, A(1g) modes do not strongly contribute to the total electron-phonon coupling constant λ. However, experimental linewidths show a remarkable agreement with ab initio calculations over the complete phonon energy range, demonstrating the accuracy of such calculations in a rare comparison to a comprehensive experimental data set.

Electron-phonon coupling and the soft phonon mode in TiSe2

We report high-resolution inelastic x-ray measurements of the soft phonon mode in the charge-density-wave compound TiSe(2). We observe a complete softening of a transverse optic phonon at the L point, i.e., q=(0.5, 0, 0.5), at T≈T(CDW). Detailed ab initio calculations for the electronic and lattice dynamical properties of TiSe(2) are in quantitative agreement with experimental frequencies for the soft phonon mode. The observed broad range of renormalized phonon frequencies, (0.3, 0, 0.5)≤q≤(0.5, 0, 0.5), is directly related to a broad peak in the electronic susceptibility stabilizing the charge-density-wave ordered state. Our analysis demonstrates that a conventional electron-phonon coupling mechanism can explain a structural instability and the charge-density-wave order in TiSe(2) although other mechanisms might further boost the transition temperature.

Response of acoustic phonons to charge and orbital order in the 50% doped bilayer manganite LaSr2Mn2O7

We report an inelastic neutron scattering study of acoustic phonons in the charge and orbitally ordered bilayer manganite LaSr(2)Mn(2)O(7). For excitation energies less than 15 meV, we observe an abrupt increase (decrease) of the phonon energies (linewidths) of a transverse acoustic phonon branch at q = (h, h, 0), h ≤ 0.3, upon entering the low temperature charge and orbital ordered state (T(COO) = 225 K). This indicates a reduced electron-phonon coupling due to a decrease of electronic states at the Fermi level leading to a partial removal of the Fermi surface below T(COO) and provides direct experimental evidence for a link between electron-phonon coupling and charge order in manganites.

Effect of Fermi surface nesting on resonant spin excitations in Ba(1-x)K(x)Fe2As2

We report inelastic neutron scattering measurements of the resonant spin excitations in Ba(1-x)K(x)Fe(2)As(2) over a broad range of electron band filling. The fall in the superconducting transition temperature with hole doping coincides with the magnetic excitations splitting into two incommensurate peaks because of the growing mismatch in the hole and electron Fermi surface volumes, as confirmed by a tight-binding model with s(±)-symmetry pairing. The reduction in Fermi surface nesting is accompanied by a collapse of the resonance binding energy and its spectral weight, caused by the weakening of electron-electron correlations.

Extended phonon collapse and the origin of the charge-density wave in 2H-NbSe2

We report inelastic x-ray scattering measurements of the temperature dependence of phonon dispersion in the prototypical charge-density-wave (CDW) compound 2H-NbSe2. Surprisingly, acoustic phonons soften to zero frequency and become overdamped over an extended region around the CDW wave vector. This extended phonon collapse is dramatically different from the sharp cusp in the phonon dispersion expected from Fermi surface nesting. Instead, our experiments, combined with ab initio calculations, show that it is the wave vector dependence of the electron-phonon coupling that drives the CDW formation in 2H-NbSe2 and determines its periodicity. This mechanism explains the so far enigmatic behavior of CDW in 2H-NbSe2 and may provide a new approach to other strongly correlated systems where electron-phonon coupling is important.

Transition from heavy-fermion to mixed-valence behavior in Ce(1-x)Y(x)Al3: a quantitative comparison with the anderson impurity model

We present a neutron scattering investigation of Ce1-xYxAl3 as a function of chemical pressure, which induces a transition from heavy-fermion behavior in CeAl3 (T{K}=5 K) to a mixed-valence state at x=0.5 (T{K}=150 K). The crossover can be modeled accurately on an absolute intensity scale by an increase in the k-f hybridization, V{kf}, within the Anderson impurity model. Surprisingly, the principal effect of the increasing V{kf} is not to broaden the low-energy components of the dynamic magnetic susceptibility but to transfer spectral weight to high energy.

Combination of human tumor necrosis factor-alpha (hTNF-alpha) gene delivery with gemcitabine is effective in models of pancreatic cancer

Pancreatic adenocarcinoma is an aggressive and highly lethal malignancy. Currently, gemcitabine is commonly used in patients with pancreatic cancer. However, the life expectancy of pancreatic cancer patients remains poor. We explored the possibility of increased anti-tumor activity by combining human tumor necrosis factor-alpha (hTNF-alpha) with current front-line therapy. Human TNF-alpha displays potent anti-tumor activity, but its use is limited by the toxicity of systemic administration. We developed a gene delivery approach using intratumoral injections of an adenoviral vector expressing hTNF-alpha, AdEgr.TNF.11D (TNFerade), to increase local concentrations of hTNF-alpha within the tumor, thereby maximizing local anti-tumor activity and yet minimizing the systemic toxicities. An ongoing phase III clinical trial is testing the efficacy of AdEgr.TNF.11D-injected intratumorally and combining with chemotherapy in locally advanced pancreatic cancer. In this study, we show that treatment with AdEgr.TNF.11D and gemcitabine results in a high level of hTNF-alpha expression in human pancreatic cancer cell lines. The combined treatment was well tolerated, highly active and produced marked delays in the growth of human pancreatic xenograft tumors relative to either agent alone. Our results strongly suggest that combination of AdEgr.TNF.11D and gemcitabine may be a potentially useful therapeutic approach for the improved treatment of pancreatic cancer.

Two-dimensional resonant magnetic excitation in BaFe1.84Co0.16As2

Inelastic neutron scattering measurements on single crystals of superconducting BaFe1.84Co0.16As2 reveal a magnetic excitation located at wave vectors (1/2 1/2 L) in tetragonal notation. On cooling below T_{C}, a clear resonance peak is observed at this wave vector with an energy of 8.6(0.5) meV, corresponding to 4.5(0.3) k_{B}T_{C}. This is in good agreement with the canonical value of 5 k_{B}T_{C} observed in the cuprates. The spectrum shows strong dispersion in the tetragonal plane but very weak dispersion along the c axis, indicating that the magnetic fluctuations are two dimensional in nature. This is in sharp contrast to the anisotropic three dimensional spin excitations seen in the undoped parent compounds.

Reentrant orbital order and the true ground state of LaSr2Mn2O7

Contrary to conventional wisdom, our purified La 2-2x Sr 1+2x Mn2O7 crystals exhibit CE-type orbital and charge order as the low-temperature ground state for a hole doping level h=0.5. For small deviations from h=0.5, the high-temperature CE phase is replaced at low temperatures by an A-type antiferromagnet without coexistence. Larger deviations result in a lack of CE order at any temperature. Thus, small inhomogeneities in cation or oxygen composition could explain why others commonly see this reentrance with coexistence.

Localized excitation in the hybridization gap in YbAl3

The intermediate valence compound YbAl3 exhibits a broad magnetic excitation in the inelastic neutron scattering spectrum with characteristic energy E1 approximately 50 meV, equal to the Kondo energy (T(K) approximately 600-700 K). In the low temperature (T < T(coh) approximately 40 K) Fermi liquid state, however, a new peak in the scattering occurs at E2 approximately 33 meV, which lies in the hybridization gap that exists in this compound. We report inelastic neutron scattering results for a single-crystal sample. The scattering at energies near E1 qualitatively has the momentum (Q) dependence expected for interband scattering across the indirect gap. The scattering near E2 has a very different Q dependence: it is a weak function of Q over a large fraction of the Brillouin zone and is smallest near (1/2,1/2, 1/2). A possibility is that the peak at E2 arises from a spatially localized excitation in the hybridization gap.

First-order metal-insulator transitions in manganites: are they universal?

Conductivity data for La(2-2x)Sr(1+2xMn2O7 (x = 0.6) show a first-order transition from an orbital- or charge-ordered insulator to a metal as the temperature falls below approximately 160 K. The change in conductivity is 100 times larger than that seen previously in any single-phase manganite in zero field. The metallic low-temperature state is similar to x = 0.58, but x = 0.58 shows no evidence of orbital or charge order. This result supports a conclusion that strongly coupled magnetic-conductive transitions are first order.

Nanomagnetic droplets and implications to orbital ordering in LA(1-x)Sr(x)CoO3

Inelastic cold-neutron scattering on LaCoO3 provided evidence for a distinct low energy excitation at 0.6 meV coincident with the thermally induced magnetic transition. Coexisting strong ferromagnetic (FM) and weaker antiferromagnetic correlations that are dynamic follow the activation to the excited state, identified as the intermediate S = 1 spin triplet. This is indicative of dynamical orbital ordering favoring the observed magnetic interactions. With hole doping as in La(1-x)Sr(x)CoO3 , the FM correlations between Co spins become static and isotropically distributed due to the formation of FM droplets. The correlation length and condensation temperature of these droplets increase rapidly with metallicity due to the double exchange mechanism.

Crystal field potential of PrOs4Sb12: consequences for superconductivity

The results of inelastic neutron scattering provide a solution for the crystal field level scheme in PrOs4Sb12, in which the ground state in the cubic crystal field potential of T(h) symmetry is a Gamma(1) singlet. The conduction electron mass enhancement is consistent with inelastic exchange scattering, and we propose that inelastic quadrupolar, or aspherical Coulomb, scattering is responsible for enhancing the superconducting transition temperature. PrOs4Sb12 appears to be the first compound in which aspherical Coulomb scattering is strong enough to overcome magnetic pair breaking and increase T(c).

Orbital and Spin Chains in ZnV2O4

Our powder inelastic neutron scattering data indicate that ZnV2O4 is a system of spin chains that are three-dimensionally tangled in the cubic phase above 50 K due to randomly occupied t(2g) orbitals of V3+ (3d(2)) ions. Below 50 K in the tetragonal phase, the chains become straight due to antiferro-orbital ordering. This is evidenced by the characteristic wave vector dependence of the magnetic structure factor that changes from symmetric to asymmetric at the cubic-to-tetragonal transition.

Magnetic correlations and the anisotropic Kondo effect in Ce1-xLaxAl3

By combining the results of muon spin relaxation and inelastic neutron scattering in the heavy fermion compounds Ce1-xLaxAl3 (0.0<or=x<or=0.2), we show that static magnetic correlations are suppressed above a characteristic temperature, T*, by electronic dissipation rather than by thermal disorder. Below T*, an energy gap opens in the single-ion magnetic response in agreement with the predictions of the anisotropic Kondo model. Scaling arguments suggest that similar behavior may underlie the "hidden order" in URu2Si2.

Orbital ordering transition in La4Ru2O10

We report experimental evidence for a full orbital ordering transition in the two-dimensional lanthanum ruthenate La4Ru2O10. The observable consequences of this orbital ordering include the loss of the Ru local moment, a structural distortion which partitions Ru-O bonds into axially oriented short and long sets, a sharp jump in electrical resistivity, and the opening of a spin gap that is visible in neutron scattering experiments. This is a rare example of a discrete orbital ordering transition in a 4d transition metal oxide and demonstrates that orbital effects can have an influence on the properties of layered ruthenates, a family of compounds that notably includes the p-wave superconductor Sr2RuO4 and the field-tuned quantum critical metamagnet Sr3Ru2O7.

Glass transition in the polaron dynamics of colossal magnetoresistive manganites

Neutron scattering measurements on a bilayer manganite near optimal doping show that the short-range polaron correlations are completely dynamic at high T, but then freeze upon cooling to a temperature T(*) approximately equal 310 K. This glass transition suggests that the paramagnetic/insulating state arises from an inherent orbital frustration that inhibits the formation of a long-range orbital- and charge-ordered state. Upon further cooling into the ferromagnetic-metallic state (T(C) = 114 K), where the polarons melt, the diffuse scattering quickly develops into a propagating, transverse optic phonon.

Communication perceptions of older adults with sensory loss and their communication partners: implications for intervention

INTRODUCTION

Vision and hearing loss are prevalent disorders in older adults although their effects on communication are not well documented.

METHOD

The purpose of this study was to investigate the perceptions of older adults with sensory loss and their communication partners with regard to their communication, situational difficulties and conversational needs.

RESULTS

Questionnaire results revealed that the sensory loss group experienced a range of functional vision and hearing difficulties. Over two-thirds of subjects reported frequent conversational difficulty, particularly in background noise and group conversations. Most subjects used clarification requests (mainly non-specific clarification and repetition requests) to overcome misunderstandings. By contrast, the communication partners reported few communication difficulties and claimed that they proactively eliminated or controlled environmental, speaker and listener variables to optimize conversation. The most frequently reported strategy was repetition.

CONCLUSION

The findings suggest that older adults with sensory loss experience communication disruptions, which in many instances are not resolved. To optimize communication efficacy in this population, a communication training programme for people with sensory loss and their communication partners is highly recommended.

Karyotype, phenotype and parental origin in 19 cases of triploidy

The parental origin of triploidy in 19 cases was examined by inheritance of DNA microsatellites and by methylation patterns of SNRPN or PW71 (where parents' blood was unavailable). The fetal and placental morphology on these cases was reviewed. The phenotype of the fetuses with non-mosaic triploidy was assessed in relation to the two types described by McFadden and Kalousek. Of the diandric fetuses three of the six showed mild-to-moderate symmetrical growth retardation and the other three had growth characteristics in accordance with their gestational ages. This study would suggest the fetal triploid 'Type 1' definition be modified to 'well grown to moderate symmetrical IUGR' to allow for such variation. In the digynic fetuses (McFadden/Kalousek Type 2) there were poor growth characteristics with IUGR being more severe and asymmetrical. The diandric fetuses were as common as digynic fetuses in this series. The ratio of diandric to digynic specimens was 11:8 but if only fetal specimens (not embryos or mosaic children) were included the ratio was 6:5. Many diandric conceptions end as partial moles but later in gestation diandric fetuses may be well grown. It is proposed that there may be a survival barrier for diandric fetuses early in gestation (possibly based on the proportion of vascularised placental villi), although once this is passed the diandric fetuses are comparatively more viable and better grown than digynic fetuses. In the XXY triploid fetuses, 5/6 had hypoplastic or ambiguous external genitalia (two were recorded as of female phenotype) as has been reported previously. In these, the gonadal histology was testicular in all the diandrics but in the single digynic XXY case, sex reversal was complete with normal uterus and Fallopian tubes and the gonads were histologically ovaries. Two triploid/diploid mosaics were proven to be due to digyny. The probable cause is delayed incorporation of the second polar body into a blastomere and there was evidence of identical alleles from the same sperm being present in both diploid and triploid cells. In one of these triploid/diploid mosaics in which there was a termination of pregnancy (TOP) after prenatal karyotyping the diploid cell line had trisomy 16 which was not evident in the triploid line. This trisomy was probably of post-zygotic origin and we suggest the fetus was rescued by the prominence of the triploid line.

Magnetic correlations and the quantum critical point of UCu5-xPdx (x = 1,1.5)

We have used inelastic neutron scattering to determine the magnetic susceptibility chi(q,omega,T) of the non-Fermi-liquid compounds UCu(5-x)Pdx (x = 1,1.5) for energies omega between 0.2 and 2 meV, and for temperatures T between 1.6 and 250 K. Spatial correlations in both UCu4Pd and UCu 3.5Pd1.5 extend over length scales comparable to the unit cell, and display very little temperature dependence. In contrast, the wave vector independent susceptibility diverges as T-->0. We find that the excitations at all q, and for all T and omega accessed display the same type of non-Fermi-liquid omega/T scaling.

Mixed lattice and electronic states in high-temperature superconductors

Inelastic neutron scattering measurements are presented which show the abrupt development of new oxygen lattice vibrations near the doping-induced metal-insulator transition in La(2--x)Sr(x)CuO(4). A direct correlation is established between these lattice modes and the electronic susceptibility (as measured by photoemission) inferring that such modes mix strongly with charge fluctuations. This electron-lattice coupling can be characterized as a localized one-dimensional response of the lattice to short-ranged metallic charge fluctuations.

Phonon density of states in MgB2

We report inelastic neutron scattering measurements of the phonon density of states in Mg 11B2, which has a superconducting transition at 39.2 K. The acoustic phonons extend in energy to 36 meV, and there are highly dispersive optic branches peaking at 54, 78, 89, and 97 meV. A simple Born-von Kàrmàn model reproduces the mode energies, and provides an estimate of the electron-phonon coupling of lambda approximately 0.9. Furthermore, the estimated boron and magnesium contributions to the isotope effect are in qualitative agreement with experiment. The data confirm that a conventional phonon mechanism, with moderately strong electron-phonon coupling, can explain the observed superconductivity.

Physicians' views on quality of care: a five-country comparison

Interest is resurging in the problems relating to the quality of patient care. This paper provides a comparative perspective on this issue from a five-country physician survey conducted in Australia, Canada, New Zealand, the United Kingdom, and the United States in 2000. Physicians in all five countries reported a recent decline in quality of care and concerns with how hospitals address medical errors. Physicians in four countries expressed serious concerns about shortages of medical specialists and inadequate facilities. U.S. physicians reported problems caused by patients' inability to pay for prescription drugs and medical care. Asked about efforts to improve quality of care in the future, physicians indicated support for electronic medical records, electronic prescribing, and initiatives to reduce medical errors.

Large harmonic softening of the phonon density of states of uranium

Phonon density-of-states curves were obtained from inelastic neutron scattering spectra from the three crystalline phases of uranium at temperatures from 50 to 1213 K. The alpha-phase showed an unusually large thermal softening of phonon frequencies. Analysis of the vibrational power spectrum showed that this phonon softening originates with the softening of a harmonic solid, as opposed to vibrations in anharmonic potentials. It follows that thermal excitations of electronic states are more significant thermodynamically than are the classical volume effects. For the alpha-beta and beta-gamma phase transitions, vibrational and electronic entropies were comparable.

The elderly in five nations: the importance of universal coverage

This paper reports 1999 survey results on the population age sixty-five and older in five nations--Australia, Canada, New Zealand, the United Kingdom, and the United States. The majority of respondents were generally satisfied with the quality, affordability, and availability of health services in their nations. In many measures of access to and cost of care, the United States looks much like the other nations surveyed. However, as the elderly view their health systems, the direction they have taken in recent years with respect to caring for the elderly, and the future affordability of care in old age, U.S. respondents tended to be more pessimistic than were those in other nations.