Exact zero-point energy shift in the e⊗(n E)e\otimes (n~E), t⊗(n H)t\otimes (n~H) many modes dynamic Jahn-Teller systems at strong coupling

We find the exact semiclassical (strong coupling) zero-point energy shifts applicable to the $e\otimes (n E)$ and $t\otimes (n H)$ dynamic Jahn-Teller problems, for an arbitrary number $n$ of discrete vibrational modes simultaneously coupled to one single electronic level. We also obtain an analytical formula for the frequency of the resulting normal modes, which has an attractive and apparently general Slater-Koster form. The limits of validity of this approach are assessed by comparison with O'Brien's previous effective-mode approach, and with accurate numerical diagonalizations. Numerical values obtained for $t\otimes (n H)$ with $n =8$ and coupling constants appropriate to C$_{60}^-$ are used for this purpose, and are discussed in the context of fullerene.Comment: 20 pages, 4 ps figure

Cross-sectional and longitudinal risk of physical impairment in a cohort of postmenopausal women who experience physical and verbal abuse.

BackgroundExposure to interpersonal violence, namely verbal and physical abuse, is a highly prevalent threat to women's health and well-being. Among older, post-menopausal women, several researchers have characterized a possible bi-directional relationship of abuse exposure and diminished physical functioning. However, studies that prospectively examine the relationship between interpersonal abuse exposure and physical functioning across multiple years of observation are lacking. To address this literature gap, we prospectively evaluate the association between abuse exposure and physical functioning in a large, national cohort of post-menopausal women across 12 years of follow-up observation.MethodsMultivariable logistic regression was used to measure the adjusted association between experiencing abuse and physical function score at baseline in 154,902 Women's Health Initiative (WHI) participants. Multilevel modeling, where the trajectories of decline in physical function were modeled as a function of time-varying abuse exposure, was used to evaluate the contribution of abuse to trajectories of physical function scores over time.ResultAbuse was prevalent among WHI participants, with 11 % of our study population reporting baseline exposure. Verbal abuse was the most commonly reported abuse type (10 %), followed by combined physical and verbal abuse (1 %), followed by physical abuse in the absence of verbal abuse (0.2 %). Abuse exposure (all types) was associated with diminished physical functioning, with women exposed to combined physical and verbal abuse presenting baseline physical functioning scores consistent with non-abused women 20 years senior. Results did not reveal a differential rate of decline over time in physical functioning based on abuse exposure.ConclusionsTaken together, our findings suggest a need for increased awareness of the prevalence of abuse exposure among postmenopausal women; they also underscore the importance of clinician's vigilance in their efforts toward the prevention, early detection and effective intervention with abuse exposure, including verbal abuse exposure, in post-menopausal women. Given our findings related to abuse exposure and women's diminished physical functioning at WHI baseline, our work illuminates a need for further study, particularly the investigation of this association in younger, pre-menopausal women so that the temporal ordering if this relationship may be better understood

Dynamical Jahn-Teller Effect and Berry Phase in Positively Charged Fullerene I. Basic Considerations

We study the Jahn-Teller effect of positive fullerene ions $^2$C$_{60}^{+}$ and $^1$C$_{60}^{2+}$. The aim is to discover if this case, in analogy with the negative ion, possesses a Berry phase or not, and what are the consequences on dynamical Jahn-Teller quantization. Working in the linear and spherical approximation, we find no Berry phase in $^1$C$_{60}^{2+}$, and presence/absence of Berry phase for coupling of one $L=2$ hole to an $L=4$/$L=2$ vibration. We study in particular the special equal-coupling case ($g_2=g_4$), which is reduced to the motion of a particle on a 5-dimensional sphere. In the icosahedral molecule, the final outcome assesses the presence/absence of a Berry phase of $\pi$ for the $h_u$ hole coupled to $G_g$/$H_h$ vibrations. Some qualitative consequences on ground-state symmetry, low-lying excitations, and electron emission from C$_{60}$ are spelled out.Comment: 31 pages (RevTeX), 3 Postscript figures (uuencoded

The Phase Diagram of Correlated Electrons in a Lattice of Berry Molecules

A model for correlated electrons in a lattice with local additional spin--1 degrees of freedom inducing constrained hopping, is studied both in the low density limit and at quarter filling. We show that in both 1D and 2D two particles form a bound state even in presence of a repulsive U<U_c. A picture of a dilute Bose gas, leading to off-diagonal long range order (LRO) in 2D (quasi-LRO in 1D), is supported by quantitative calculations in 1D which allow for a determination of the phase diagram.Comment: 7 pages + 2 ps figures, published versio

Enhanced Electron Pairing in a Lattice of Berry Phase Molecules

We show that electron hopping in a lattice of molecules possessing a Berry phase naturally leads to pairing. Our building block is a simple molecular site model inspired by C$_{60}$, but realized in closer similarity with Na$_3$. In the resulting model electron hopping must be accompanied by orbital operators, whose function is to switch on and off the Berry phase as the electron number changes. The effective hamiltonians (electron-rotor and electron-pseudospin) obtained in this way are then shown to exhibit a strong pairing phenomenon, by means of 1D linear chain case studies. This emerges naturally from numerical studies of small $N$-site rings, as well as from a BCS-like mean-field theory formulation. The pairing may be explained as resulting from the exchange of singlet pairs of orbital excitations, and is intimately connected with the extra degeneracy implied by the Berry phase when the electron number is odd. The relevance of this model to fullerides, to other molecular superconductors, as well as to present and future experiments, is discussed.Comment: 30 pages, RevTe

Reproductive parameters of "Nero di Parma" sows reared outdoor and indoor

AbstractThe swine genetic type "Nero di Parma" has been obtained after a preservation programme of a local breed suitable for outdoor rearing systems in Parma province. Actually, 480 females and 35 males are registered by Italian Swine Breeders Association and are reared in 28 herds of Parma province. The study involved the analysis of the reproductive performance of 120 sows from 19 boars, born between 1999 and 2005, during 211 parities from 2002 to 2006. For each parity, the boar, the age of the sow, the length of the farrowing interval, and the litter size (number of born alive, stillborn and weaned piglets) were recorded. Two rearing systems of the farrowing sows (from the final phase of gestation to the end of lactation) were considered: indoor (sows closed off in individual stalls or farrowing cages) and outdoor (sows in individual huts inside the paddocks, with straw bedding); dry sows in both systems had access on pasture with forage and concentrate integration. Data concerning sows performance we..

Mapping host-related correlates of influenza vaccine-induced immune response: An umbrella review of the available systematic reviews and meta-analyses

Seasonal influenza is the leading infectious disease in terms of its health and socioeconomic impact. Annual immunization is the most efficient way to reduce this burden. Several correlates of influenza vaccine-induced protection are commonly used, owing to their ready availability and cheapness. Influenza vaccine-induced immunogenicity is a function of host-, virus-and vaccine-related factors. Host-related factors constitute the most heterogeneous group. The objective of this study was to analyze the available systematic evidence on the host factors able to modify influenza vaccine-induced immunogenicity. An umbrella review approach was undertaken. A total of 28 systematic reviews/meta-analyses were analyzed—these covered the following domains: intravenous drug use, psychological stress, acute and chronic physical exercise, genetic polymorphisms, use of pre-/pro-/symbiotics, previous Bacillus Calmette–Guérin vaccination, diabetes mellitus, vitamin D supplementation/deficiency, latent cytomegalovirus infection and various forms of immunosuppression. In order to present effect sizes on the same scale, all possible meta-analyses were re-performed and cumulative evidence synthesis ranking was carried out. The meta-analysis was conducted separately on each health condition category and virus (sub)type. A total of 97 pooled estimates were used in order to construct an evidence-based stakeholder-friendly map. The principal public health implications are discussed

Orthorhombic fulleride (CH3NH2)K3C60 close to Mott-Hubbard instability: Ab initio study

We study the electronic structure and magnetic interactions in methylamine-intercalated orthorhombic alkali-doped fullerene (CH3NH2)K3C60 within the density functional theory. As in the simpler ammonia intercalated compound (NH3)K3C60, the orthorhombic crystal-field anisotropy \Delta lifts the t1u triple degeneracy at the \Gamma point and drives the system deep into the Mott-insulating phase. However, the computed \Delta and conduction electron bandwidth W cannot alone account for the abnormally low experimental N\'eel temperature, T_N = 11 K of the methylamine compound, compared to the much higher value T_N = 40 K of the ammonia one. Significant interactions between CH3NH2 and C60^{3-} are responsible for the stabilization of particular pseudo-Jahn-Teller fullerene-cage distortions and the ensuing low-spin S = 1/2 state. These interactions also seem to affect the magnetic properties, as interfullerene exchange interactions depend on the relative orientation of pseudo-Jahn-Teller distortions of neighboring C60^{3-} molecules. For the ferro-orientational order of CH3NH2-K^+ groups we find an apparent reduced dimensionality in magnetic exchange interactions, which may explain the suppressed N\'eel temperature. The disorder in exchange interactions caused by orientational disorder of CH3NH2-K^+ groups could further contribute to this suppression.Comment: 8 pages, 5 figures, 1 tabl

Electron--Vibron Interactions and Berry Phases in Charged Buckminsterfullerene: Part I

A simple model for electron-vibron interactions on charged buckminsterfullerene C$_{60}^{n-}$, $n=1,\ldots 5$, is solved both at weak and strong couplings. We consider a single $H_g$ vibrational multiplet interacting with $t_{1u}$ electrons. At strong coupling the semiclassical dynamical Jahn-Teller theory is valid. The Jahn-Teller distortions are unimodal for $n$=1,2,4,5 electrons, and bimodal for 3 electrons. The distortions are quantized as rigid body pseudo--rotators which are subject to geometrical Berry phases. These impose ground state degeneracies and dramatically change zero point energies. Exact diagonalization shows that the semiclassical level degeneracies and ordering survive well into the weak coupling regime. At weak coupling, we discover an enhancement factor of $5/2$ for the pair binding energies over their classical values. This has potentially important implications for superconductivity in fullerides, and demonstrates the shortcoming of Migdal--Eliashberg theory for molecular crystals.Comment: 29 pages (+7 figures, 3 available upon request), LATEX, report-number: BM515

The role of the Berry Phase in Dynamical Jahn-Teller Systems

The presence/absence of a Berry phase depends on the topology of the manifold of dynamical Jahn-Teller potential minima. We describe in detail the relation between these topological properties and the way the lowest two adiabatic potential surfaces get locally degenerate. We illustrate our arguments through spherical generalizations of the linear T x h and H x h cases, relevant for the physics of fullerene ions. Our analysis allows us to classify all the spherical Jahn-Teller systems with respect to the Berry phase. Its absence can, but does not necessarily, lead to a nondegenerate ground state.Comment: revtex 7 pages, 2 eps figures include