416 research outputs found
New Bacteriological Patterns in Primary Infected Aorto-iliac Aneurysms: A Single-centre Experience
AbstractObjectivesTo assess causative pathogens and surgical outcomes in patients with primary infected aorto-iliac aneurysms at our institution.DesignRetrospective study of patients treated at a university hospital between 1992 and 2009.ResultsWe identified 26 patients (median age, 63 years) with primary infected aneurysms on the aorta (descending thoracic, n = 2; thoraco-abdominal, n = 3; suprarenal, n = 2; infrarenal, n = 15) or iliac arteries (n = 4). Among them, 22 were symptomatic, including 13 with ruptured aneurysms. The causative organisms, identified in 25/26 patients, were Campylobacter fetus, n = 6; Streptococcus pneumoniae, n = 4; Listeria, n = 3; Salmonella, n = 2; Mycobacterium tuberculosis, n = 2; Staphylococcus aureus, n = 1; and other, n = 7. Immune suppression was a feature in 10 (38.4%) patients. Revascularisation was performed in situ in 23 patients (10 allografts, eight grafts, three superficial femoral veins, and 2 stentgrafts) and by extra-anatomic bypass in three patients.Hospital mortality was 23% (in situ group, 17.4%; extra-anatomic group, 66.7%; Ï2 Yates, P = 0.24). During follow-up in the 20 survivors (median, 48.5 months), there were two non-infection-related deaths (five and 24 months) and six (30%) vascular complications.ConclusionsThe bacteriological spectrum of primary infected aorto-iliac aneurysms was wider than previously reported. The availability of new diagnostic tests and increased prevalence of immunosuppression may explain this finding
Self-optimized adaptive algorithms for equalization and carrier recovering. Application to underwater communications
This paper is concerned with the joint estimation of Doppler shift and equalization
in digital communications. After a brief recall of the classical transversal adaptive
equalizer a joint algorithm estimating Doppler and equalizer is presented . The
tracking of non-stationarities of the transmission channel is considered and an
asymptotically optimum self-optimizing algorithm is proposed . Its performances
are evaluated by simulations. Finally, this algorithm is applied in the case of a
real underwater acoustic transmission .Ce papier traite du problÚme de l'estimation conjointe du Doppler et des coefficients d'un égaliseur. AprÚs un bref rappel concernant l'égalisation adaptative transverse, nous proposons un algorithme estimant conjointement le Doppler et les coefficients d'un égaliseur. Cet algorithme conjoint est asymptotiquement optimum en poursuite des non-stationnarités lentes du canal de transmission. Ses performances sont mises en évidence à l'aide de données synthétiques et de signaux réels issus d'expérimentations dans le domaine des transmissions acoustiques sous-marine
Challenges in shallow target reconstruction by 3D elastic full-waveform inversion - Which initial model?
Elastic full-waveform inversion (FWI) is a powerful tool for high-resolution subsurface multiparameter characterization. However, 3D FWI applied to land data for near-surface applications is particularly challenging because the seismograms are dominated by highly energetic, dispersive, and complex-scattered surface waves (SWs). In these conditions, a successful deterministic FWI scheme requires an accurate initial model. Our study, primarily focused on field data analysis for 3D applications, aims at enhancing the resolution in the imaging of complex shallow targets, by integrating devoted SW analysis techniques with a 3D spectral-element-based elastic FWI. From dispersion curves, extracted from seismic data recorded over a sharp-interface shallow target, we build different initial S-wave (VS) and P-wave (VP) velocity models (laterally homogeneous and laterally variable), using a specific data transform. Starting from these models, we carry out 3D FWI tests on synthetic and field data, using a relatively straightforward inversion scheme. The field data processing before FWI consists of band-pass filtering and muting of noisy traces. During FWI, a weighting function is applied to the far-offset traces. We test 2D and 3D acquisition layouts, with different positions of the sources and variable offsets. The 3D FWI workflow enriches the overall content of the initial models, allowing a reliable reconstruction of the shallow target, especially when using laterally variable initial models. Moreover, a 3D acquisition layout guarantees a better reconstruction of the target's shape and lateral extension. In addition, the integration of model-oriented (preliminary monoparametric FWI) and data-oriented (time windowing) strategies into the main optimization scheme has produced further improvement of the FWI results
Children with supratentorial midline pilocytic astrocytomas exhibit multiple progressions and acquisition of neurologic deficits over time
Pilocytic astrocytomas are the most common solid tumor of childhood and can arise anywhere in the central nervous system, including the posterior fossa (pf-PA), supratentorial midline (sm-PA; including optic pathway, hypothalamus, thalamus), and brainstem (bs-PA). Location (sm, bs) has been previously proposed as a prognostic factor for PA, but is difficult to separate from resection status on multivariate analysis. To overcome this limitation, we assembled a large cohort of children (n = 251) with biopsy-proved PA treated at St. Louis Childrenâs Hospital from 2003 â 2021 and analyzed outcomes only in patients with subtotal resection (STR; n = 81). We excluded patients with NF1, as NF1-associated gliomas often display a more indolent clinical course than their counterparts. We identified that children with STR sm-PA had a higher likelihood of multiple progressions compared to children with STR bs-PA and pf-PA. This was associated with worsening neurologic deficits over time, consistent with the sm location as a poor prognostic factor. Furthermore, the only children in our cohort with leptomeningeal dissemination or death harbored sm-PAs. Tumors in this location were also associated with an increased likelihood of non-BRAF-fusion genetic alterations and multiple oncogenic mutations. Overall, these data support location as an independent prognostic factor for PA in cases in which a gross-total resection cannot be achieved. Treating neuro-oncologists may thus wish to consider early intervention rather than watch-and-wait strategies at first progression of STR sm-PA. These patients may also benefit from earlier consideration of molecularly targeted therapy
Delayed Decision-making in Real-time Beatbox Percussion Classification
This is an electronic version of an article published in Journal of New Music Research, 39(3), 203-213, 2010. doi:10.1080/09298215.2010.512979. Journal of New Music Research is available online at: www.tandfonline.com/openurl?genre=article&issn=1744-5027&volume=39&issue=3&spage=20
Synchronizing Sequencing Software to a Live Drummer
Copyright 2013 Massachusetts Institute of Technology. MIT allows authors to archive published versions of their articles after an embargo period. The article is available at
Exploitations agricoles familiales en Afrique de l'Ouest et du Centre
L'agriculture Africaine a évolué rapidement depuis une cinquantaine d'années, passant de l'autosubsistance familiale à l'intégration aux marchés. Cet ouvrage décrit les défis auxquels sont confrontés les agriculteurs d'Afrique de l'Ouest et Centrale, et aborde les thÚmes de la mondialisation, de la disponibilité d'équipements et d'intrants, ainsi que du besoin de méthodes de gestion plus efficaces et d'un appui accru aux agriculteurs
Exploitations agricoles familiales en Afrique de l'Ouest et du Centre
L'agriculture Africaine a évolué rapidement depuis une cinquantaine d'années, passant de l'autosubsistance familiale à l'intégration aux marchés. Cet ouvrage décrit les défis auxquels sont confrontés les agriculteurs d'Afrique de l'Ouest et Centrale, et aborde les thÚmes de la mondialisation, de la disponibilité d'équipements et d'intrants, ainsi que du besoin de méthodes de gestion plus efficaces et d'un appui accru aux agriculteurs
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