A Quantum Adiabatic Evolution Algorithm Applied to Random Instances of an NP-Complete Problem

A quantum system will stay near its instantaneous ground state if the Hamiltonian that governs its evolution varies slowly enough. This quantum adiabatic behavior is the basis of a new class of algorithms for quantum computing. We test one such algorithm by applying it to randomly generated, hard, instances of an NP-complete problem. For the small examples that we can simulate, the quantum adiabatic algorithm works well, and provides evidence that quantum computers (if large ones can be built) may be able to outperform ordinary computers on hard sets of instances of NP-complete problems.Comment: 15 pages, 6 figures, email correspondence to [email protected] ; a shorter version of this article appeared in the April 20, 2001 issue of Science; see http://www.sciencemag.org/cgi/content/full/292/5516/47

Microgravity Studies of Cells and Tissues: from Mir to ISS

In vitro studies of cells and tissues in microgravity, either simulated by cultivation conditions on earth or reduced by spaceflight, are essential for the identification of mechanisms underlying gravity sensing and transduction in biological organisms. In this paper, we review rotating bioreactor studies of engineered skeletal and cardiovascular tissues carried out in unit gravity, a Shuttle-Mir study of cartilage tissue engineering, and the ongoing development and testing of a Cell Culture Unit for cell and tissue cultivation aboard the ISS

Laser surgery of early glottic cancer in elderly

Aim of this retrospective study is to evaluate the impact of transoral laser surgery of early glottic cancer in elderly patients in terms of feasibility, disease-free survival, overall survival and organ preservation, in a single Institute (European Institute of Oncology). A total of 122 patients (male/female ratio 113/9), over 70s with untreated early stage glottic cancer, were consecutively evaluated and treated at the European Institute of Oncology from 2000 to 2008. None had contraindications to general anaesthesia and all patients signed informed consent to this surgical treatment. The severity of pre-operative comorbidities and the intra-operative risk were evaluated according to the American Society of Anaesthesiologists Grading classification. All patients underwent laser cordectomies according to the European Laryngological Society classification. Histopathological examination demonstrated no evidence of tumour (pT0) in 19 patients (calculated only in patients with a previous vocal cord biopsy positive for squamous cell carcinoma), pTis in 18, pT1a in 53, pT1b in 16, pT2 in 14 and pT3 in 2, respectively. A 10-year overall survival, a tumour specific survival and a laryngeal tumour-specific survival were, respectively, 64.9%, 84.8% and 94.3%. In conclusion, transoral laser surgery is feasible in elderly patients with early stage glottic cancer, providing good results in terms of disease-free survival, organ preservation and quality of life. Our group of elderly patients had no intra-operative or post-surgical complications and resumed normal activities the day after discharge from hospital. Considering these factors, we can assess, that transoral laser surgery, therefore, represents a modern treatment that should be offered as an alternative to conventional radiotherapy in elderly patients with early glottic cancer referred to medical centres with expertise for this surgical procedure

Using Verification Technology to Specify and Detect Malware

Computer viruses and worms are major threats for our computer infrastructure, and thus, for economy and society at large. Recent work has demonstrated that a model checking based approach to malware detection can capture the semantics of security exploits more accurately than traditional approaches, and consequently achieve higher detection rates. In this approach, malicious behavior is formalized using the expressive specification language CTPL based on classic CTL. This paper gives an overview of our toolchain for malware detection and presents our new system for computer assisted generation of malicious code specifications

Abstract Interpretation of Indexed Grammars.

Indexed grammars are a generalization of context-free grammars and recognize a proper subset of context-sensitive languages. The class of languages recognized by indexed grammars are called indexed languages and they correspond to the languages recognized by nested stack automata. For example indexed grammars can recognize the language {a^n b^n c^n | n > = 1} which is not context-free, but they cannot recognize {(ab^n)^n) | n >= 1} which is context-sensitive. Indexed grammars identify a set of languages that are more expressive than context-free languages, while having decidability results that lie in between the ones of context-free and context-sensitive languages. In this work we study indexed grammars in order to formalize the relation between indexed languages and the other classes of languages in the Chomsky hierarchy. To this end, we provide a fixpoint characterization of the languages recognized by an indexed grammar and we study possible ways to abstract, in the abstract interpretation sense, these languages and their grammars into context-free and regular languages

The importance of including soil carbon changes, ecotoxicity and biodiversity impacts in environmental life cycle assessments of organic and conventional milk in Western Europe

Estimates of soil carbon changes, biodiversity and ecotoxicity have often been missing from life cycle assessment based studies of organic dairy products, despite evidence that the impacts of organic and conventional management may differ greatly within these areas. The aim of the present work was therefore to investigate the magnitude of including these impact categories within a comprehensive environmental impact assessment of organic and conventional dairy systems differing in basic production conditions. Three basic systems representative of a range of European approaches to dairy production were selected for the analysis, i.e. (i) low-land mixed crop-livestock systems, (ii) lowland grassland-based systems, (iii) and mountainous systems. As in previous publications, this study showed that when assessing climate change, eutrophication and acidification impact organic milk has similar or slightly lower impact than conventional, although land-use is higher under organic management. Including soil carbon changes reduced the global warming potential by 5–18%, mostly in organic systems with a high share of grass in the ration. The impacts of organic milk production on freshwater ecotoxicity, biodiversity and resource depletion were 2, 33 and 20% of the impacts of conventional management, respectively, across the basic systems considered. The study highlights the importance of including biodiversity, ecotoxicity and soil carbon changes in life cycle assessments when comparing organic and conventional agricultural products. Furthermore, the study shows that including more grass in the ration of dairy cows increases soil carbon sequestration and decreases the negative impact on biodiversity.info:eu-repo/semantics/acceptedVersio

Intensified ChlVPP/ABVVP chemotherapy regimen and pegfilgrastim support in advanced Hodgkin lymphoma

We present feasibility, toxicity and efficacy results of an intensified six-cycle ChlVPP/ABVVP regimen in advanced Hodgkin lymphoma (HL). From February 2004 to August 2007, 82 consecutive eligible patients were enrolled. According to the Hasenclever index, 64 patients (78%) were considered at low risk, 15 (18%) at intermediate and 3 (4%) at high risk. The most relevant toxicity was haematological: grade 3–4 neutropenia occurred in 32% of patients, grade 3–4 anaemia in 26% of patients. Severe infections and febrile neutropenia were observed in 8% of patients. With a median follow-up of 35 months (range 12–55), the three-year freedom from treatment failure (FFTF) and overall survival (OS) were 75% (95% CI 65%–86%) and 94% (95% CI 87%–99%), respectively. The intensified ChlVPP/ABVVP regimen in advanced HL is effective, does not seem to differ from standard regimens in terms of FFTF and OS and showed a favourable toxicity profile