550 research outputs found

    Superconductivity from correlated hopping

    Full text link
    We consider a chain described by a next-nearest-neighbor hopping combined with a nearest-neighbor spin flip. In two dimensions this three-body term arises from a mapping of the three-band Hubbard model for CuO2_2 planes to a generalized tJt-J model and for large O-O hopping favors resonance-valence-bond superconductivity of predominantly dd-wave symmetry. Solving the ground state and low-energy excitations by analytical and numerical methods we find that the chain is a Luther-Emery liquid with correlation exponent Kρ=(2n)2/2K_{\rho} = (2-n)^2/2, where nn is the particle density.Comment: 10 pages, RevTeX 3.0 + 2 PostScript figs. Accepted for publication in Phys.Rev.

    Managing lifestyle change to reduce coronary risk: a synthesis of qualitative research on peoples’ experiences

    Get PDF
    Background Coronary heart disease is an incurable condition. The only approach known to slow its progression is healthy lifestyle change and concordance with cardio-protective medicines. Few people fully succeed in these daily activities so potential health improvements are not fully realised. Little is known about peoples’ experiences of managing lifestyle change. The aim of this study was to synthesise qualitative research to explain how participants make lifestyle change after a cardiac event and explore this within the wider illness experience. Methods A qualitative synthesis was conducted drawing upon the principles of meta-ethnography. Qualitative studies were identified through a systematic search of 7 databases using explicit criteria. Key concepts were identified and translated across studies. Findings were discussed and diagrammed during a series of audiotaped meetings. Results The final synthesis is grounded in findings from 27 studies, with over 500 participants (56% male) across 8 countries. All participants experienced a change in their self-identity from what was ‘familiar’ to ‘unfamiliar’. The transition process involved ‘finding new limits and a life worth living’ , ‘finding support for self’ and ‘finding a new normal’. Analyses of these concepts led to the generation of a third order construct, namely an ongoing process of ‘reassessing past, present and future lives’ as participants considered their changed identity. Participants experienced a strong urge to get back to ‘normal’. Support from family and friends could enable or constrain life change and lifestyle changes. Lifestyle change was but one small part of a wider ‘life’ change that occurred. Conclusions The final synthesis presents an interpretation, not evident in the primary studies, of a person-centred model to explain how lifestyle change is situated within ‘wider’ life changes. The magnitude of individual responses to a changed health status varied. Participants experienced distress as their notion of self identity shifted and emotions that reflected the various stages of the grief process were evident in participants’ accounts. The process of self-managing lifestyle took place through experiential learning; the level of engagement with lifestyle change reflected an individual’s unique view of the balance needed to manage ‘realistic change’ whilst leading to a life that was perceived as ‘worth living’. Findings highlight the importance of providing person centred care that aligns with both psychological and physical dimensions of recovery which are inextricably linked

    Survivorship, complications, and outcomes following distal femoral arthroplasty for non-neoplastic indications

    Get PDF
    Aims: Endoprosthetic reconstruction with a distal femoral arthroplasty (DFA) can be used to treat distal femoral bone loss from oncological and non-oncological causes. This study reports the short-term implant survivorship, complications, and risk factors for patients who underwent DFA for non-neoplastic indications. Methods: We performed a retrospective review of 75 patients from a single institution who underwent DFA for non-neoplastic indications, including aseptic loosening or mechanical failure of a previous prosthesis (n = 25), periprosthetic joint infection (PJI) (n = 23), and native or periprosthetic distal femur fracture or nonunion (n = 27). Patients with less than 24 months’ follow-up were excluded. We collected patient demographic data, complications, and reoperations. Reoperation for implant failure was used to calculate implant survivorship. Results: Overall one- and five-year implant survivorship was 87% and 76%, respectively. By indication for DFA, mechanical failure had one- and five-year implant survivorship of 92% and 68%, PJI of 91% and 72%, and distal femur fracture/nonunion of 78% and 70% (p = 0.618). A total of 37 patients (49%) experienced complications and 27 patients (36%) required one or more reoperation. PJI (n = 16, 21%), aseptic loosening (n = 9, 12%), and wound complications (n = 8, 11%) were the most common complications. Component revision (n = 10, 13.3%) and single-stage exchange for PJI (n = 9, 12.0 %) were the most common reoperations. Only younger age was significantly associated with increased complications (mean 67 years (SD 9.1)) with complication vs 71 years (SD 9.9) without complication; p = 0.048). Conclusion: DFA is a viable option for distal femoral bone loss from a range of non-oncological causes, demonstrating acceptable short-term survivorship but with high overall complication rates.Lewis Katz School of Medicin

    Early participation in a prenatal food supplementation program ameliorates the negative association of food insecurity with quality of maternal-infant interaction.

    Get PDF
    Food insecurity is detrimental to child development, yet little is known about the combined influence of food insecurity and nutritional interventions on child development in low-income countries. We proposed that women assigned to an early invitation time to start a prenatal food supplementation program could reduce the negative influence of food insecurity on maternal-infant interaction. A cohort of 180 mother-infant dyads were studied (born between May and October 2003) from among 3267 in the randomized controlled trial Maternal Infant Nutritional Interventions Matlab, which was conducted in Matlab, Bangladesh. At 8 wk gestation, women were randomly assigned an invitation time to start receiving food supplements (2.5 MJ/d; 6 d/wk) either early (~9 wk gestation; early-invitation group) or at the usual start time (~20 wk gestation; usual-invitation group) for the government program. Maternal-infant interaction was observed in homes with the use of the Nursing Child Assessment Satellite Training Feeding Scale, and food-insecurity status was obtained from questionnaires completed when infants were 3.4-4.0 mo old. By using a general linear model for maternal-infant interaction, we found a significant interaction (P = 0.012) between invitation time to start a prenatal food supplementation program and food insecurity. Those in the usual-invitation group with higher food insecurity scores (i.e., more food insecure) had a lower quality of maternal-infant interaction, but this relationship was ameliorated among those in the early-invitation group. Food insecurity limits the ability of mothers and infants to interact well, but an early invitation time to start a prenatal food supplementation program can support mother-infant interaction among those who are food insecure

    Neural correlates of rhythm in post-stroke aphasia (online Early)

    Get PDF
    ndividuals with post-stroke aphasia have long been observed to show relatively preserved musical and rhythm abilities in the presence of varied, and often profound, language impairments. Accordingly, speech-language pathologists frequently use rhythm-based strategies (e.g., tapping) to facilitate speech output in people with aphasia. However, there is little empirical work to support the clinical practice of using rhythm techniques.In this study, we investigated the neural bases of rhythm in aphasia by combining thorough behavioral rhythm assessments with structural brain imaging. Individuals with chronic, post-stroke aphasia (n=33) and a matched neurotypical control group (n=29) completed a rigorous battery of rhythm production and perception tasks.We found marked individual variability within the aphasia group, with about one third of individuals showing impaired rhythm processing, while the remaining two-thirds performed within the control range. Using lesion-symptom mapping, we found that individual variability in tapping performance was associated with damage to a left temporoparietal area, extending into white matter specifically in the arcuate fasciculus. That is, individuals who struggled with tapping tended to have damage to this region. Tapping was also associated with language production scores, but not motor speech, in the aphasia group.These findings, which systematically link rhythm, language, and the brain, have the potential of being translated into clinical practice for understanding which patients may benefit the most from rhythm-based treatments. Our study in a population with focal brain injury complements evolutionary work highlighting the importance of the left temporo-parietal region and underlying white matter for beat synchronization

    Survivorship, complications, and outcomes following distal femoral arthroplasty for non-neoplastic indications.

    Get PDF
    AIMS: Endoprosthetic reconstruction with a distal femoral arthroplasty (DFA) can be used to treat distal femoral bone loss from oncological and non-oncological causes. This study reports the short-term implant survivorship, complications, and risk factors for patients who underwent DFA for non-neoplastic indications. METHODS: We performed a retrospective review of 75 patients from a single institution who underwent DFA for non-neoplastic indications, including aseptic loosening or mechanical failure of a previous prosthesis (n = 25), periprosthetic joint infection (PJI) (n = 23), and native or periprosthetic distal femur fracture or nonunion (n = 27). Patients with less than 24 months\u27 follow-up were excluded. We collected patient demographic data, complications, and reoperations. Reoperation for implant failure was used to calculate implant survivorship. RESULTS: Overall one- and five-year implant survivorship was 87% and 76%, respectively. By indication for DFA, mechanical failure had one- and five-year implant survivorship of 92% and 68%, PJI of 91% and 72%, and distal femur fracture/nonunion of 78% and 70% (p = 0.618). A total of 37 patients (49%) experienced complications and 27 patients (36%) required one or more reoperation. PJI (n = 16, 21%), aseptic loosening (n = 9, 12%), and wound complications (n = 8, 11%) were the most common complications. Component revision (n = 10, 13.3%) and single-stage exchange for PJI (n = 9, 12.0 %) were the most common reoperations. Only younger age was significantly associated with increased complications (mean 67 years (SD 9.1)) with complication vs 71 years (SD 9.9) without complication; p = 0.048). CONCLUSION: DFA is a viable option for distal femoral bone loss from a range of non-oncological causes, demonstrating acceptable short-term survivorship but with high overall complication rates

    Parenting Styles Are Associated With Overall Child Dietary Quality Within Low-Income and Food-Insecure Households

    Get PDF
    Objective: To examine the association between parenting styles and overall child dietary quality within households that are low-income and food-insecure. Design: Child dietary intake was measured via a 24 h dietary recall. Dietary quality was assessed using the Healthy Eating Index-2005 (HEI-2005). Parenting styles were measured and scored using the Parenting Styles and Dimensions Questionnaire. Linear regressions were used to test main and interaction associations between HEI-2005 scores and parenting styles. Setting: Non-probability sample of low-income and food-insecure households in South Carolina, USA. Participants: Parent–child dyads (n 171). Parents were ≥18 years old and children were 9–15 years old. Results: We found a significant interaction between authoritative and authoritarian parenting style scores. For those with a mean authoritarian score, each unit increase in authoritative score was associated with a higher HEI-2005 score (b = 3·36, P \u3c 0.05). For those with an authoritarian score that was 1 SD above the mean authoritarian score, each unit increase in authoritative score was associated with a higher HEI-2005 score (b = 8.42, P \u3c 0.01). For those with an authoritarian score that was −1 SD below the mean authoritarian score, each unit increase in authoritative score was associated with a lower HEI-2005 score; however, this was not significant (b = −1·69, P \u3e 0·05). Permissive parenting style scores were negatively associated with child dietary quality (b = −2·79, P \u3c 0·05). Conclusions: Parenting styles should be considered an important variable that is associated with overall dietary quality in children living within low-income and food-insecure households
    corecore