One of the simplest pseudo-Hermitian models with real spectrum (viz., square-well on a real interval I of coordinates) is re-examined. A PT −symmetric complex deformation C of I is introduced and shown tractable via an innovated approach to matching conditions. The result is surprising: an arbitrarily small deformation I → C implies a sudden collapse (i.e., the spontaneous PT −symmetry breaking...

We investigate the effect of modified gravity on cluster abundance and the SunyaevZel’dovich angular power spectrum. Our modified gravity is based on a phenomenological extension of the Dvali-Gabadadze-Porrati model which includes two free parameters characterizing deviation from ΛCDM cosmology. Assuming that Birkhoff’s theorem gives a reasonable approximation, we study the spherical collapse m...

There are widespread concerns that current trends in resource-use are unsustainable, but possibilities of overshoot/collapse remain controversial. Collapses have occurred frequently in history, often followed by centuries of economic, intellectual, and population decline. Many different natural and social phenomena have been invoked to explain specific collapses, but a general explanation remai...

We consider the dynamics of a contracting universe ruled by two minimally coupled scalar fields with general exponential potentials. This model describes string-inspired scenarios in the Einstein frame. Both background and perturbations can be solved analytically in this model. Curvature perturbations are generated with a scale invariant spectrum only for a dust-like collapse, as happens for a ...

We consider the dynamics of a contracting universe ruled by two minimally coupled scalar fields with general exponential potentials. This model describes string-inspired scenarios in the Einstein frame. Both background and perturbations can be solved analytically in this model. Curvature perturbations are generated with a scale invariant spectrum only for a dust-like collapse, as happens for a ...

Abstract: A finite element model is verified accurate enough to simulate the static test of one reinforced-concrete frame with specially shaped columns subjected to the loss of a ground corner column. As the frame sustained loads primarily depending on the beam resisting mechanism in the test, four related parameters, namely the height of beam section, rebar ratio of beam, rebar ratio of slab a...

We have studied the relationship between emphysema and airways collapse, and response to corticosteroids in patients with chronic airflow obstruction. One hundred and seven patients completed a placebo-controlled trial comparing 2 wks treatment with oral prednisolone 40 mg.day-1 to inhaled beclomethasone dipropionate 500 micrograms t.d.s. Response to corticosteroids was defined on the basis of ...

The problem of communication among nodes in an extended network is considered, where radio power decay and interference are limiting factors. It has been shown previously that, with simple multi-hopping, the achievable total communication rate in such a network is at most Θ( √ N). In this work, we study the benefit of node cooperation in conjunction with multi-hopping on the network capacity. W...