6,920 research outputs found

    Completeness on the worm domain and the M\"untz-Sz\'asz problem for the Bergman space

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    In this paper we are concerned with the problem of completeness in the Bergman space of the worm domain WÎŒ\mathcal{W}_\mu and its truncated version WÎŒâ€Č\mathcal{W}'_\mu. We determine some orthogonal systems and show that they are not complete, while showing that the union of two particular of such systems is complete. In order to prove our completeness result we introduce the Muentz-Szasz problem for the 1-dimensional Bergman space of the disk {ζ:âˆŁÎ¶âˆ’1∣<1}\{\zeta : |\zeta-1|<1\} and find a sufficient condition for its solution.Comment: 14 pages, Author Accepted Manuscrip

    Aerodynamics of a rigid curved kite wing

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    A preliminary numerical study on the aerodynamics of a kite wing for high altitude wind power generators is proposed. Tethered kites are a key element of an innovative wind energy technology, which aims to capture energy from the wind at higher altitudes than conventional wind towers. We present the results obtained from three-dimensional finite volume numerical simulations of the steady air flow past a three-dimensional curved rectangular kite wing (aspect ratio equal to 3.2, Reynolds number equal to 3x10^6). Two angles of incidence -- a standard incidence for the flight of a tethered airfoil (6{\deg}) and an incidence close to the stall (18{\deg}) -- were considered. The simulations were performed by solving the Reynolds Averaged Navier-Stokes flow model using the industrial STAR-CCM+ code. The overall aerodynamic characteristics of the kite wing were determined and compared to the aerodynamic characteristics of the flat rectangular non twisted wing with an identical aspect ratio and section (Clark Y profile). The boundary layer of both the curved and the flat wings was considered to be turbulent throughout. It was observed that the curvature induces only a mild deterioration of the aerodynamics properties. Pressure distributions around different sections along the span are also presented, together with isolines of the average pressure and kinetic energy fields at a few sections across the wing and the wake. Our results indicate that the curvature induces a slower spatial decay of the vorticity in the wake, and in particular, inside the wing tip vortices.Comment: 13 pages, 13 figures. Submitted to "Renewable Energy

    Age-related changes of the noradrenergic and acetylcholinesterase reactive nerve fibres innervating the pigeon bursa of Fabricius.

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    Age-dependent changes in the innervation of the pigeon (Columba livia, L.) bursa of Fabricius, from hatching to 120 days of age, were studied by fluorescence-histochemical and neurochemical methods for demonstrating noradrenergic and acetylcholinesterase (AChE)-reactive nerve fibres respectively. The distribution of both nerve fibre types was largely perivascular. Furthermore, a few isolated nerve fiber profiles were observed beneath the bursal epithelium, in the interfollicular septa and in the follicular cortex. No nerve fibre profiles reaching the medulla of the lymphoid follicles were observed. In addition to nerve fibres, AChE reactive neuron-like cells were encountered within the capsule and interfollicular septa. AChE reactivity was also found in dendritic-like cells localized in the cortical and cortico-medullary border. No changes in the density of perivascular noradrenergic innervation were noticeable during the ages studied, whereas the density of AChE-reactive fibres supplying vessels reached the adult pattern at 30 days, and then remained unvaried. The density of non-perivascular nerve fiber profiles, specially the AChE reactive type, increased until 30 days, remained unchanged until 75 days and then increased with aging (90-120 days). The interrelationship between the autonomic nervous system and the immune system is discussed

    Class of PPT bound entangled states associated to almost any set of pure entangled states

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    We analyze a class of entangled states for bipartite d⊗dd \otimes d systems, with dd non-prime. The entanglement of such states is revealed by the construction of canonically associated entanglement witnesses. The structure of the states is very simple and similar to the one of isotropic states: they are a mixture of a separable and a pure entangled state whose supports are orthogonal. Despite such simple structure, in an opportune interval of the mixing parameter their entanglement is not revealed by partial transposition nor by the realignment criterion, i.e. by any permutational criterion in the bipartite setting. In the range in which the states are Positive under Partial Transposition (PPT), they are not distillable; on the other hand, the states in the considered class are provably distillable as soon as they are Nonpositive under Partial Transposition (NPT). The states are associated to any set of more than two pure states. The analysis is extended to the multipartite setting. By an opportune selection of the set of multipartite pure states, it is possible to construct mixed states which are PPT with respect to any choice of bipartite cuts and nevertheless exhibit genuine multipartite entanglement. Finally, we show that every kk-positive but not completely positive map is associated to a family of nondecomposable maps.Comment: 12 pages, 3 figures. To appear in Phys. Rev.

    Transient hypercortisolism and symptomatic hyperthyroidism associated to primary hyperparathyroidism in an elderly patient: case report and literature review.

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    Abstract Background: Primary hyperparathyroidism (PHPT) is often found on routine blood tests, at a relatively asymptomatic stage. However many studies suggest different systemic effects related to PHPT, which could be enhanced by an abnormal cortisol release due to chronic stress of hyperparathyroidism. Being PHPT frequently found in the 6th to 7th decade of life, a careful and multifaceted approach should be taken. Case presentation: We report the case of an elderly patient with symptomatic PHPT and incidental pulmonary embolism. He was treated with hydration, zoledronic acid, cinacalcet and high-dose unfractionated heparin. Parathyroid surgery was successfully performed, but patient's conditions suddenly worsened because of a transient thyrotoxicosis, probably induced by a previous exposure to iodine load and/or thyroid surgical manipulation. A short-term treatment with beta-blockers was introduced for symptomatic relief. The patient also presented a transient hypercortisolism with elevated ACTH, likely due to stress related not only to aging and hospitalization but also to PHPT, resolved only four months after parathyroid surgery. Conclusion: Chronic hyperparathyroidism has been linked with increased all-cause mortality. A functional chronic hypercortisolism could be established, enhancing PHPT related disorders. Only parathyroid surgery has been demonstrated to cure PHPT and complications related, showing similar outcome between older and younger patients. However, the management of post-operative period should be more careful in fragile patients. In particular, the early diagnosis and treatment of a transient post-operative thyrotoxicosis could improve recovery. Due to the increase in prevalence and the evidence of many related complications even in asymptomatic PHPT, expert opinion-based guidelines for surgical treatment of PHPT should be developed especially for elderly patients

    Research Report: High Tunnel Tomato Fruit Cluster Pruning

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    Tomatoes are a high value crop grown worldwide. Indeterminate varieties are commonly grown in high tunnel structures throughout New England for the fresh market. Indeterminate tomato plants often suffer from a phenomenon called ‘June drop’ in which the plant’s first four to five cluster of fruit set perfectly but the subsequent two to three clusters have poor set and plant productivity drops suddenly. While cluster thinning (e.g., reducing the number of fruit allowed to mature per cluster) has been successfully shown to increase fruit size, it has generally not increased marketable yield. We hypothesized that reducing the fruit load by thinning clusters OR removing alternate clusters could reduce the stress placed on plants, and therefore permit more sustained fruit production throughout the season. We compared five fruit cluster-pruning treatments: control (no fruit pruned), 6 (six fruit per cluster), 3 (three fruit per cluster), 6A (every other cluster removed and six fruit per remaining cluster) and 3A (every other cluster removed and three fruit per remaining cluster). Compared with plants that were not cluster-pruned, removal of alternate clusters did produce more consistent fruit production, but overall yield was lower than for unpruned plants. Cluster pruning treatments increased fruit size, but cracking incidence increased as fruit size increased. Vegetative growth was significantly increased by reducing fruit load; however, this was not correlated with greater yields and required additional labor for increased trellising and sucker removal. Results from this preliminary experiment did not suggest that removing alternate fruit clusters is beneficial

    Providing assistance to incarcerated fathers who have child support obligations can help their post-release community reintegration

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    Among the growing discussions about race, justice, inequality and incarceration there has been a greater concern over the financial obligations placed on those who are convicted of crimes. In new research, Caterina G. Roman and Nathan W. Link examine the effects of ongoing child support payments on incarcerated fathers after their release, finding that less than a third had their payments changed whilst in prison, and that over 90 percent had payments in arrears after release. They argue that the multiple social services involved with incarcerated fathers both pre and post imprisonment need to provide more coordinated support so that child support orders do not become unwieldy, burdensome arrears
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