The Subcolonization and Buildup of \u3ci\u3eTetrastichus Julis,\u3c/i\u3e (Hymenoptera: Eulophidae) a Larval Parasitoid of the Cereal Leaf Beetle, (Coleoptera: Chrysomelidae) in the Lower Peninsula of Michigan

Following initial establishment of the parasitoid, Tetrastichus julis (Walker), at a carefully managed field nursery, releases of parasitized Oulema melanopus larvae were made by Michigan county agents at preselected sites throughout the lower peninsula during 1970-74. A follow-up recovery program during 1971-75 revealed continued dispersion and population increase for T. julis. An independent census verified the increasing rates of parasitism

Magnetic properties of the Anderson model: a local moment approach

We develop a local moment approach to static properties of the symmetric Anderson model in the presence of a magnetic field, focussing in particular on the strong coupling Kondo regime. The approach is innately simple and physically transparent; but is found to give good agreement, for essentially all field strengths, with exact results for the Wilson ratio, impurity magnetization, spin susceptibility and related properties.Comment: 7 pages, 3 postscript figues. Latex 2e using the epl.cls Europhysics Letters macro packag

Finite temperature dynamics of the Anderson model

The recently introduced local moment approach (LMA) is extended to encompass single-particle dynamics and transport properties of the Anderson impurity model at finite-temperature, T. While applicable to arbitrary interaction strengths, primary emphasis is given to the strongly correlated Kondo regime (characterized by the T=0 Kondo scale $\omega_{\rm K}$). In particular the resultant universal scaling behaviour of the single-particle spectrum D(\omega; T) \equiv F(\frac{\w}{\omega_{\rm K}}; \frac{T}{\omega_{\rm K}}) within the LMA is obtained in closed form; leading to an analytical description of the thermal destruction of the Kondo resonance on all energy scales. Transport properties follow directly from a knowledge of $D(\omega; T)$. The $T / \omega_{\rm K}$-dependence of the resulting resistivity $\rho(T)$, which is found to agree rather well with numerical renormalization group calculations, is shown to be asymptotically exact at high temperatures; to concur well with the Hamann approximation for the s-d model down to $T/\omega_{\rm K} \sim 1$, and to cross over smoothly to the Fermi liquid form $\rho (T) - \rho (0) \propto -(T/\omega_{\rm K})^2$ in the low-temperature limit. The underlying approach, while naturally approximate, is moreover applicable to a broad range of quantum impurity and related models

Dynamics and transport properties of heavy fermions: theory

The paramagnetic phase of heavy fermion systems is investigated, using a non-perturbative local moment approach to the asymmetric periodic Anderson model within the framework of dynamical mean field theory. The natural focus is on the strong coupling Kondo-lattice regime wherein single-particle spectra, scattering rates, dc transport and optics are found to exhibit w/w_L,T/w_L scaling in terms of a single underlying low-energy coherence scale w_L. Dynamics/transport on all relevant (w,T)-scales are encompassed, from the low-energy behaviour characteristic of the lattice coherent Fermi liquid, through incoherent effective single-impurity physics likewise found to arise in the universal scaling regime, to non-universal high-energy scales; and which description in turn enables viable quantitative comparison to experiment.Comment: 27 pages, 12 figure

Excess Body Weight and Gait Influence Energy Cost of Walking in Older Adults

Purpose: To study how excess body weight influences the energy cost of walking (Cw) and determine if overweight and obese older adults self-select stride frequency to minimize Cw. Methods: Using body mass index (BMI) men and women between the ages of 65–80 yr were separated into normal weight (NW, BMI ≤ 24.9 kg m−2, n = 13) and overweight-obese groups (OWOB, BMI ≥25.0 kg m−2, n = 13). Subjects walked at 0.83 m s−1 on an instrumented treadmill that recorded gait parameters, and completed three, six-minute walking trials; at preferred stride frequency (PSF), at +10% PSF, and at −10% PSF. Cw was determined by indirect calorimetry. Repeated measures analysis of variance was used to compare groups, and associations were tested with Pearson correlations, α = 0.05. Results: OWOB had 62% greater absolute Cw (301 ± 108 vs. 186 ± 104 J m−1, P \u3c 0.001) and 20% greater relative Cwkg (3.48 ± 0.95 vs. 2.91 ± 0.94 J kg−1 m−1, P = 0.046) than NW. Although PSF was not different between OWOB and NW (P = 0.626), Cw was 8% greater in OWOB at +10% PSF (P \u3c 0.001). At PSF OWOB spent less time in single-limb support (33.1 ± 1.5 vs. 34.9 ± 1.6 %GC, P = 0.021) and more time in double-limb support (17.5 ± 1.6 vs. 15.4 ± 1.4 %GC, P = 0.026) than NW. In OWOB, at PSF, Cw was correlated to impulse (r = −0.57, P = 0.027) and stride frequency (r = 0.51, P = 0.046). Conclusions: Excess body weight is associated with greater Cw in older adults, possibly contributing to reduced mobility in overweight and obese older persons

Field-dependent dynamics of the Anderson impurity model

Single-particle dynamics of the Anderson impurity model in the presence of a magnetic field $H$ are considered, using a recently developed local moment approach that encompasses all energy scales, field and interaction strengths. For strong coupling in particular, the Kondo scaling regime is recovered. Here the frequency ($\omega/\omega_{\rm K}$) and field ($H/\omega_{\rm K}$) dependence of the resultant universal scaling spectrum is obtained in large part analytically, and the field-induced destruction of the Kondo resonance investigated. The scaling spectrum is found to exhibit the slow logarithmic tails recently shown to dominate the zero-field scaling spectrum. At the opposite extreme of the Fermi level, it gives asymptotically exact agreement with results for statics known from the Bethe ansatz. Good agreement is also found with the frequency and field-dependence of recent numerical renormalization group calculations. Differential conductance experiments on quantum dots in the presence of a magnetic field are likewise considered; and appear to be well accounted for by the theory. Some new exact results for the problem are also established

Single-particle dynamics of the Anderson model: a local moment approach

A non-perturbative local moment approach to single-particle dynamics of the general asymmetric Anderson impurity model is developed. The approach encompasses all energy scales and interaction strengths. It captures thereby strong coupling Kondo behaviour, including the resultant universal scaling behaviour of the single-particle spectrum; as well as the mixed valent and essentially perturbative empty orbital regimes. The underlying approach is physically transparent and innately simple, and as such is capable of practical extension to lattice-based models within the framework of dynamical mean-field theory.Comment: 26 pages, 9 figure

The Divisive Power of Humour: Comedy, Taste and Symbolic Boundaries

Using British and Dutch interview data, this article demonstrates how people from different social classes draw strong symbolic boundaries on the basis of comedy taste. Eschewing the omnivorousness described in recent studies of cultural consumption, comedy audiences make negative aesthetic and moral judgements on the basis of comedy taste, and often make harsh judgements without the disclaimers, apologies and ambivalence so typical of ‘taste talk’ in contemporary culture. The article demonstrates how, in particular, Dutch and British middle class audiences use their comedy taste to communicate distinction and cultural superiority. We discuss several reasons why such processes of social distancing exist in comedy taste and not other cultural areas: the traditionally low status of comedy; the strong relation between humour and personhood; the continuity between comedy tastes and humour styles in everyday life; as well as the specific position of comedy in the British and Dutch cultural fields

Spiritual support during COVID-19 in England: a scoping study of online sources

Spiritual support is a key element of holistic care, and better healthcare professionals training and stronger strategic guidelines become urgent in light of health disasters and emergencies, such as the COVID-19 pandemic. To this end, the aim of this study was to explore spiritual support provision within mass and social media and the websites of spiritual leaders, institutions and NHS chaplaincy units during COVID-19 in England, between March and May 2020. A scoping review design informed by Levac and colleagues’ five-staged framework was adopted, and adapted with a multi-strategy search to scope the different domains of online sources. Results revealed that spiritual support for dying patients, their families, health care staff, spiritual leaders and chaplains, had to be drastically reduced, both in quality and quantity, as well as being provided via different technological devices or domestic symbolic actions. No mention was found of a central strategy for the provision of spiritual support. This study points to the importance of developing centralized strategies to prepare healthcare systems and professionals in relation to spiritual support provision, both routinely and during health disasters and emergencies. Further research will have to explore innovative practices, in particular the role of digital technologies, in spiritual support provision

Zero-bias conductance in carbon nanotube quantum dots

We present numerical renormalization group calculations for the zero-bias conductance of quantum dots made from semiconducting carbon nanotubes. These explain and reproduce the thermal evolution of the conductance for different groups of orbitals, as the dot-lead tunnel coupling is varied and the system evolves from correlated Kondo behavior to more weakly correlated regimes. For integer fillings $N=1,2,3$ of an SU(4) model, we find universal scaling behavior of the conductance that is distinct from the standard SU(2) universal conductance, and concurs quantitatively with experiment. Our results also agree qualitatively with experimental differential conductance maps.Comment: 4 pages, 5 figure