Interfacial layering in a three-component polymer system

We study theoretically the temporal evolution and the spatial structure of the interface between two polymer melts involving three different species (A, A* and B). The first melt is composed of two different polymer species A and A* which are fairly indifferent to one another (Flory parameter chi_AA* ~ 0). The second melt is made of a pure polymer B which is strongly attracted to species A (chi_AB 0). We then show that, due to these contradictory tendencies, interesting properties arise during the evolution of the interface after the melts are put into contact: as diffusion proceeds, the interface structures into several adjacent "compartments", or layers, of differing chemical compositions, and in addition, the central mixing layer grows in a very asymmetric fashion. Such unusual behaviour might lead to interesting mechanical properties, and demonstrates on a specific case the potential richness of multi-component polymer interfaces (as compared to conventional two-component interfaces) for various applications.Comment: Revised version, to appear in Macromolecule

Magnetic properties of Ni2.18Mn0.82Ga Heusler alloys with a coupled magnetostructural transition

Polycrystalline Ni2.18Mn0.82Ga Heusler alloys with a coupled magnetostructural transition are studied by differential scanning calorimetry, magnetic and resistivity measurements. Coupling of the magnetic and structural subsystems results in unusual magnetic features of the alloy. These uncommon magnetic properties of Ni2.18Mn0.82Ga are attributed to the first-order structural transition from a tetragonal ferromagnetic to a cubic paramagnetic phase.Comment: 4 pages, 4 figures, revtex

Density functional calculations of nanoscale conductance

Density functional calculations for the electronic conductance of single molecules are now common. We examine the methodology from a rigorous point of view, discussing where it can be expected to work, and where it should fail. When molecules are weakly coupled to leads, local and gradient-corrected approximations fail, as the Kohn-Sham levels are misaligned. In the weak bias regime, XC corrections to the current are missed by the standard methodology. For finite bias, a new methodology for performing calculations can be rigorously derived using an extension of time-dependent current density functional theory from the Schroedinger equation to a Master equation.Comment: topical review, 28 pages, updated version with some revision

Developments in the negative-U modelling of the cuprate HTSC systems

The paper deals with the many stands that go into creating the unique and complex nature of the HTSC cuprates above Tc as below. Like its predecessors it treats charge, not spin or lattice, as prime mover, but thus taken in the context of the chemical bonding relevant to these copper oxides. The crucial shell filling, negative-U, double-loading fluctuations possible there require accessing at high valent local environment as prevails within the mixed valent, inhomogeneous two sub-system circumstance of the HTSC materials. Close attention is paid to the recent results from Corson, Demsar, Li, Johnson, Norman, Varma, Gyorffy and colleagues.Comment: 44 pages:200+ references. Submitted to J.Phys.:Condensed Matter, Sept 7 200

The Impact of Nurse-Led Environmental Controls on Insomnia in Elderly Acute Care Inpatients

The Impact of Nurse-Led Environmental Controls on Insomnia in Elderly Acute Care Inpatients Research Question: Does teaching nurses to control the patient environment (I) in acute care in-patients aged 65+ (P) reduce insomnia compared to current practice (Q1H rounding) (C) from 67.4% to less than 30% as measured by the Insomnia Severity Index (ISI) (O)? Background and Significance: 67.4% of hospitalized patients report experiencing insomnia from sleep disturbances, which can significantly impact their recovery and overall health outcomes. Nurses can address these disruptions by monitoring noise, light exposure, and staff interruptions. Sample methods: The literature review search keywords were sleep hygiene, sleep hygiene therapy, improved sleep, factors affecting sleep, sleep in hospitalized patients, insomnia, delirium, sleep disorders, acute-care sleep therapy, med-surg sleep therapy, geriatric, ages 65+. The search was conducted using the databases CINAHL and PubMed, resulting in 75 research studies. After applying filters for the last 5 years, RN author or application, RCT or quasi-experimental, and English language, the sample yielded 10. Sample: Three studies on insomnia and non-pharmacological interventions for improvement in sleep hygiene. Results: The body of evidence shows that environmental control interventions are statistically significant in reducing insomnia severity in acute care inpatients aged 65+, as measured by the Insomnia Severity Index (ISI). Conclusion: Implementing nurse-led environmental modifications to improve sleep quality in acute inpatients aged 65+ is recommended as a change in practice. Future research should explore the long-term effects of these interventions on patient outcomes related to insomnia and hospitalization-related complications

Country Inequality Rankings and Conversion Schemes

Two conversion schemes are usually employed for assessing personal-income inequality from household equivalent incomes: to weight household units by size or by needs.Using data from the Luxembourg Income Study, we show the sensitivity of country inequality rankings to conversion schemes and explain the finding by means of inequality decomposition. A bootstrap approach is implemented to test for statistical significance of our results