This paper provides some new evidence on the behaviour of cross‐country growth rates. We reject the linear model commonly used to study cross‐country growth behaviour in favour of a multiple regime alternative in which different economies obey different linear models when grouped according to initial conditions. Further, the marginal product of capital is shown to vary with the level of economic development. These results are consistent with growth models which exhibit multiple steady states. Our results call into question inferences that have been made in favour of the convergence hypothesis and further suggest that the explanatory power of the Solow growth model may be enhanced with a theory of aggregate production function differences.

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Oncolytic herpes simplex virus type 1 (HSV-1) vectors are promising therapeutic agents for cancer. Their efficacy depends on the extent of both intratumoral viral replication and induction of a host antitumor immune response. To enhance these properties while employing ample safeguards, two conditionally replicating HSV-1 vectors, termed G47⌬ and R47⌬, have been constructed by deleting the ␣47 gene and the promoter region of US11 from ␥34.5-deficient HSV-1 vectors, G207 and R3616, respectively. Because the ␣47 gene product is responsible for inhibiting the transporter associated with antigen presentation (TAP), its absence led to increased MHC class I expression in infected human cells. Moreover, some G47⌬-infected human melanoma cells exhibited enhanced stimulation of matched antitumor T cell activity. The deletion also places the late US11 gene under control of the immediate-early ␣47 promoter, which suppresses the reduced growth properties of ␥34.5-deficient mutants. G47⌬ and R47⌬ showed enhanced viral growth in a variety of cell lines, leading to higher virus yields and enhanced cytopathic effect in tumor cells. G47⌬ was significantly more efficacious in vivo than its parent G207 at inhibiting tumor growth in both immune-competent and immune-deficient animal models. Yet, when inoculated into the brains of HSV-1-sensitive A͞J mice at 2 ؋ 10 6 plaque forming units, G47⌬ was as safe as G207. These results suggest that G47⌬ may have enhanced antitumor activity in humans.

Summary1. Kernel-density estimation (KDE) is one of the most widely used home-range estimators in ecology. The recommended implementation uses least squares crossvalidation (LSCV) to calculate the smoothing factor ( h ) which has a considerable influence on the home-range estimate. 2. We tested the performance of least squares cross-validated kernel-density estimation (LSCV KDE) using data from global positioning system (GPS)-collared lions subsampled to simulate the effects of hypothetical radio-tracking strategies. 3. LSCV produced variable results and a 7% failure rate for fewer than 100 locations ( n = 2069) and a 61% failure rate above 100 points ( n = 1220). Patterns of failure and variation were not consistent among lions, reflecting different individual space use patterns. 4. Intensive use of core areas and site fidelity by animals caused LSCV to fail more often than anticipated from studies that used computer-simulated data. 5. LSCV failures at large sample sizes and variation at small sample sizes, limits the applicability of LSCV KDE to fewer situations than the literature suggests, and casts doubts over the method's reliability and comparability as a home-range estimator.