Sun Dual Theory For Bi-Continuous Semigroups

The sun dual space corresponding to a strongly continuous semigroup is a known concept when dealing with dual semigroups, which are in general only weak ∗-continuous. In this paper we develop a corresponding theory for bi-continuous semigroups under mild assumptions on the involved locally convex topologies. We also discuss sun reflexivity and Favard spaces in this context, extending classical results by van Neerven.</p

Satisfying the Einstein-Podolsky-Rosen criterion with massive particles

In 1935, Einstein, Podolsky and Rosen (EPR) questioned the completeness of quantum mechanics by devising a quantum state of two massive particles with maximally correlated space and momentum coordinates. The EPR criterion qualifies such continuous-variable entangled states, where a measurement of one subsystem seemingly allows for a prediction of the second subsystem beyond the Heisenberg uncertainty relation. Up to now, continuous-variable EPR correlations have only been created with photons, while the demonstration of such strongly correlated states with massive particles is still outstanding. Here, we report on the creation of an EPR-correlated two-mode squeezed state in an ultracold atomic ensemble. The state shows an EPR entanglement parameter of 0.18(3), which is 2.4 standard deviations below the threshold 1/4 of the EPR criterion. We also present a full tomographic reconstruction of the underlying many-particle quantum state. The state presents a resource for tests of quantum nonlocality and a wide variety of applications in the field of continuous-variable quantum information and metrology.Comment: 8 pages, 7 figure

Self-organization and Mechanical Properties of Active Filament Bundles

A phenomenological description for active bundles of polar filaments is presented. The activity of the bundle results from crosslinks, that induce relative displacements between the aligned filaments. Our generic description is based on momentum conservation within the bundle. By specifying the internal forces, a simple minimal model for the bundle dynamics is obtained, capturing generic dynamic behaviors. In particular, contracted states as well as solitary and oscillatory waves appear through dynamic instabilities. The introduction of filament adhesion leads to self-organized persistent filament transport. Furthermore, calculating the tension, homogeneous bundles are shown to be able to actively contract and to perform work against external forces. Our description is motivated by dynamic phenomena in the cytoskeleton and could apply to stress-fibers and self-organization phenomena during cell-locomotion.Comment: 19 pages, 10 figure

0.75 atoms improve the clock signal of 10,000 atoms

Since the pioneering work of Ramsey, atom interferometers are employed for precision metrology, in particular to measure time and to realize the second. In a classical interferometer, an ensemble of atoms is prepared in one of the two input states, whereas the second one is left empty. In this case, the vacuum noise restricts the precision of the interferometer to the standard quantum limit (SQL). Here, we propose and experimentally demonstrate a novel clock configuration that surpasses the SQL by squeezing the vacuum in the empty input state. We create a squeezed vacuum state containing an average of 0.75 atoms to improve the clock sensitivity of 10,000 atoms by 2.05 dB. The SQL poses a significant limitation for today's microwave fountain clocks, which serve as the main time reference. We evaluate the major technical limitations and challenges for devising a next generation of fountain clocks based on atomic squeezed vacuum.Comment: 9 pages, 6 figure

Head and neck cancer in the elderly: a retrospective study over 10 years (1999 - 2008)

INTRODUCTION: Treatment of elderly patients is in many ways different from that for younger ones. The aim of the present study was to identify the particular characteristics and needs of elderly patients suffering from head and neck cancer. From these patterns, considerations for this special group can be deduced. Patients and Material The subjects for this study consisted of 376 patients suffering from head and neck cancer that were treated between 1999 and 2008, 99 (26.3.%) of whom were older than 70 years and were evaluated retrospectively concerning smoking/alcohol abuse, ASA status, kind of malignant neoplasm, localization and treatment. RESULTS: The male-female ratio was 53:46, and mean age, 79 years (71 - 98). Out of 95 patients with a squamous cell carcinoma, 4 patients had a verrucous form. Out of 99 patients, 26 had a maxillary carcinoma and 12 patients had experienced previous non-head-and-neck cancer. An ASA score of 2 or 3 was found in 86 of the patients. CONCLUSION: The group of patients with head and neck cancer who were older than 70 years was characterized by a higher portion of female patients, a higher number of maxillary carcinomas, and a higher prevalence of previous second cancer. Making decisions in cancer therapy for elderly patients is challenging. Patients suffering from operable head and neck cancer should be treated with curative intent and with regard to quality of life if a careful assessment of comorbidities is performed preoperatively

Broad-based employee stock options in the US: Company performance and characteristics

This paper analyses data on 490 companies with broad-based stock option plans, matched to data from CompuStat in order to compare their characteristics and performance to that of other public companies. Major findings are that 1) companies with broadbased plans have higher levels of labor productivity, employment growth, and sales growth than otherwise-similar firms; 2) productivity and profitability levels rise as broadbased plans are adopted, and 3) average compensation levels are higher among such companies both before and after the introduction of broad-based plans, indicating that stock options appear to come on top of other compensation

Requirements for contractility in disordered cytoskeletal bundles

Actomyosin contractility is essential for biological force generation, and is well understood in highly organized structures such as striated muscle. Additionally, actomyosin bundles devoid of this organization are known to contract both in vivo and in vitro, which cannot be described by standard muscle models. To narrow down the search for possible contraction mechanisms in these systems, we investigate their microscopic symmetries. We show that contractile behavior requires non-identical motors that generate large enough forces to probe the nonlinear elastic behavior of F-actin. This suggests a role for filament buckling in the contraction of these bundles, consistent with recent experimental results on reconstituted actomyosin bundles.Comment: 10 pages, 6 figures; text shortene

Malignant minor salivary gland tumors: a retrospective study of 27 cases

PURPOSE: Malignant tumors of the intra-oral minor salivary glands are uncommon. The aim of this study was to give information concerning the clinical features of these tumors, the distribution of location, treatment opportunities, and outcome. METHODS: Twenty-seven patients with malignant salivary gland tumors that were treated between January 1999 and December 2008 were evaluated retrospectively. RESULTS: Of the 27 minor salivary gland carcinomas, 48.1% were adenoid cystic carcinomas (ACC), 29.7% mucoepidermoid carcinomas (MEC), 22.2% adenocarcinomas (ADCA). The most common first symptom was a painless swelling in 60% of the cases, with the second most common symptom being ulcers (28%). Four recurrences and two metastases were found. No recurrence was observed in ADCA. All four patients experiencing a recurrence developed it in the first 3 years after treatment. CONCLUSION: Wide excision with a clinical margin of 1 cm and in large tumors, positive surgical margins or perineural infiltration and postoperative radiotherapy (RT) can be recommended; but in order to give exact information concerning the possible benefit from postoperative RT, it needs large prospective multicenter studies. Long-term follow-up controls and in particularly longer than 5 years in ACC including yearly chest X-rays should be offered to these patients because of late metastasis and recurrences