Multi-Coset Sparse Imaging Arrays

We develop an efficient structured sparse antenna array architecture for coherent imaging of sparse but otherwise unknown scenes. In this architecture, the array elements are configured in a periodic nonuniform pattern that can be viewed as the superposition of multiple sparse uniform subarrays. For such structure, we develop an efficient pattern design procedure using co-array analysis, and we describe robust and efficient algorithms implementing the required associated array processing, which comprise scene support recovery, followed by image reconstruction. In addition, we develop a practical method for detecting reconstruction failures when the scene density exceeds the level for which the array was designed, so that false images are not produced. As a demonstration of its viability, the architecture is used to reconstruct a simulated natural scene.National Science Foundation (U.S.) (Grant CCF-1017772)Semiconductor Research Corporation. Center for Circuits and Systems SolutionsUnited States. Air Force (Contract FA8721-05-C-0002

Topological Andr\'e-Quillen homology for cellular commutative SS-algebras

Topological Andr\'e-Quillen homology for commutative $S$-algebras was introduced by Basterra following work of Kriz, and has been intensively studied by several authors. In this paper we discuss it as a homology theory on CW $S$-algebras and apply it to obtain results on minimal atomic $p$-local $S$-algebras which generalise those of Baker and May for $p$-local spectra and simply connected spaces. We exhibit some new examples of minimal atomic $S$-algebras.Comment: Final revision, a version will appear in Abhandlungen aus dem Mathematischen Seminar der Universitaet Hambur

Ring closing reaction in diarylethene captured by femtosecond electron crystallography

The photoinduced ring-closing reaction in diarylethene, which serves as a model system for understanding reactive crossings through conical intersections, was directly observed with atomic resolution using femtosecond electron diffraction. Complementary ab initio calculations were also performed. Immediately following photoexcitation, subpicosecond structural changes associated with the formation of an open-ring excited-state intermediate were resolved. The key motion is the rotation of the thiophene rings, which significantly decreases the distance between the reactive carbon atoms prior to ring closing. Subsequently, on the few picosecond time scale, localized torsional motions of the carbon atoms lead to the formation of the closed-ring photoproduct. These direct observations of the molecular motions driving an organic chemical reaction were only made possible through the development of an ultrabright electron source to capture the atomic motions within the limited number of sampling frames and the low data acquisition rate dictated by the intrinsically poor thermal conductivity and limited photoreversibility of organic materials

Observability and nonlinear filtering

This paper develops a connection between the asymptotic stability of nonlinear filters and a notion of observability. We consider a general class of hidden Markov models in continuous time with compact signal state space, and call such a model observable if no two initial measures of the signal process give rise to the same law of the observation process. We demonstrate that observability implies stability of the filter, i.e., the filtered estimates become insensitive to the initial measure at large times. For the special case where the signal is a finite-state Markov process and the observations are of the white noise type, a complete (necessary and sufficient) characterization of filter stability is obtained in terms of a slightly weaker detectability condition. In addition to observability, the role of controllability in filter stability is explored. Finally, the results are partially extended to non-compact signal state spaces

Characterization of a population of Fusarium oxysporum f. sp. vasinfectum causing wilt of cotton in Australia

Following the discovery of fusarium wilt in Australian cotton crops in 1993, isolates of Fusarium oxysporum f. sp. vasinfectum were collected from 6 cotton farms on the Darling Downs of Queensland. Using a range of procedures the Australian isolates could not be differentiated from each other, but they did differ from foreign isolates of the pathogen in a number of characteristics. Pathogenically, the isolates behaved similarly to race 6 of the pathogen when inoculated onto differential lines. Using aesculin hydrolysis tests, however, it was difficult to match local isolates with any of the known races. Additionally, none of the foreign isolates examined produced detectable volatile compounds when grown on a starch substrate, while all Australian isolates produced a distinctive odour during these tests. The local strain was not vegetatively compatible with any of the foreign isolates and belonged in a single, unique vegetative compatibility group. It is speculated that the Australian strain arose locally, perhaps from a minor population becoming prominent in response to wide-scale planting of highly susceptible cotton cultivars. These findings have significant implications for control of the disease and spread of the pathogen in Australia

Raster-scan imaging with normal-incidence, midinfrared InAs/GaAs quantum dot infrared photodetectors

We demonstrate normal incidence infrared imaging with quantum dot infrared photodetectors using a raster-scan technique. The device heterostructure, containing multiple layers of InAs/GaAs self-organized quantum dots, were grown by molecular-beam epitaxy. Individual devices have been operated at temperatures as high as 150 K and, at 100 K, are characterized by λpeak = 3.72 μm,λpeak=3.72μm, Jdark = 6×10−10 A/cm2Jdark=6×10−10A/cm2 for a bias of 0.1 V, and D∗ = 2.94×109 cm Hz1/2/WD∗=2.94×109cmHz1/2/W at a bias of 0.2 V. Raster-scan images of heated objects and infrared light sources were obtained with a small (13×13)(13×13) interconnected array of detectors (to increase the photocurrent) at 80 K. © 2002 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70691/2/APPLAB-80-18-3265-1.pd

Consensus standards for acquisition, measurement, and reporting of intravascular optical coherence tomography studies

Objectives: The purpose of this document is to make the output of the International Working Group for Intravascular Optical Coherence Tomography (IWG-IVOCT) Standardization and Validation available to medical and scientific communities, through a peer-reviewed publication, in the interest of improving the diagnosis and treatment of patients with atherosclerosis, including coronary artery disease. Background: Intravascular optical coherence tomography (IVOCT) is a catheter-based modality that acquires images at a resolution of ∼10 μm, enabling visualization of blood vessel wall microstructure in vivo at an unprecedented level of detail. IVOCT devices are now commercially available worldwide, there is an active user base, and the interest in using this technology is growing. Incorporation of IVOCT in research and daily clinical practice can be facilitated by the development of uniform terminology and consensus-based standards on use of the technology, interpretation of the images, and reporting of IVOCT results. Methods: The IWG-IVOCT, comprising more than 260 academic and industry members from Asia, Europe, and the United States, formed in 2008 and convened on the topic of IVOCT standardization through a series of 9 national and international meetings. Results: Knowledge and recommendations from this group on key areas within the IVOCT field were assembled to generate this consensus document, authored by the Writing Committee, composed of academicians who have participated in meetings and/or writing of the text. Conclusions: This document may be broadly used as a standard reference regarding the current state of the IVOCT imaging modality, intended for researchers and clinicians who use IVOCT and analyze IVOCT data

Ecological impacts of non-native Pacific oysters (Crassostrea gigas) and management measures for protected areas in Europe

Pacific oysters are now one of the most ‘globalised’ marine invertebrates. They dominate bivalve aquaculture production in many regions and wild populations are increasingly becoming established, with potential to displace native species and modify habitats and ecosystems. While some fishing communities may benefit from wild populations, there is now a tension between the continued production of Pacific oysters and risk to biodiversity, which is of particular concern within protected sites. The issue of the Pacific oyster therefore locates at the intersection between two policy areas: one concerning the conservation of protected habitats, the other relating to livelihoods and the socio-economics of coastal aquaculture and fishing communities. To help provide an informed basis for management decisions, we first summarise evidence for ecological impacts of wild Pacific oysters in representative coastal habitats. At local scales, it is clear that establishment of Pacific oysters can significantly alter diversity, community structure and ecosystem processes, with effects varying among habitats and locations and with the density of oysters. Less evidence is available to evaluate regional-scale impacts. A range of management measures have been applied to mitigate negative impacts of wild Pacific oysters and we develop recommendations which are consistent with the scientific evidence and believe compatible with multiple interests. We conclude that all stakeholders must engage in regional decision making to help minimise negative environmental impacts, and promote sustainable industry development

Study design and rationale for Optimal aNtiplatelet pharmacotherapy guided by bedSIDE genetic or functional TESTing in elective percutaneous coronary intervention patients (ONSIDE TEST): a prospective, open-label, randomised parallel-group multicentre trial (NCT01930773)

BACKGROUND AND AIM: High platelet reactivity (HPR) and presence of CYP2C19 loss-of-function alleles are associated with higher risk for periprocedural myocardial infarction in clopidogrel-treated patients undergoing percutaneous coronary intervention (PCI). It is unknown whether personalised treatment based on platelet function testing or genotyping can prevent such complications. METHODS: The ONSIDE-TEST is a multicentre, prospective, open-label, randomised controlled clinical trial aiming to assess if optimisation of antiplatelet therapy based on either phenotyping or genotyping is superior to conventional care. Patients will be randomised into phenotyping, genotyping, or control arms. In the phenotyping group, patients will be tested with the VerifyNow P2Y12 assay before PCI, and patients with a platelet reactivity unit greater than 208 will be switched over to prasugrel, while others will continue on clopidogrel therapy. In the genotyping group, carriers of the *2 loss-of-function allele will receive prasugrel for PCI, while wild-type subjects will be treated with clopidogrel. Patients in the control arm will be treated with standard-dose clopidogrel. The primary endpoint of the study is the prevalence of periprocedural myocardial injury within 24 h after PCI in the controls as compared to the phenotyping and genotyping group. Secondary endpoints include cardiac death, myocardial infarction, definite or probable stent thrombosis, or urgent repeat revascularisation within 30 days of PCI. Primary safety outcome is Bleeding Academic Research Consortium (BARC) type 3 and 5 bleeding during 30 days of PCI. SUMMARY: The ONSIDE TEST trial is expected to verify the clinical utility of an individualised antiplatelet strategy in preventing periprocedural myocardial injury by either phenotyping or genotyping