3,951 research outputs found
A Porthole on the Fontan Circuit
No full textThe Fontan operation, using an external conduit, is no exception. From the chest x-ray film one can only appreciate the change in the shape of the heart and chest to heart ratio before and after the operation. However, a new graft conduit with radiographic markers has been introduced as a possible external conduit for Fontan’s palliation and is visible on chest roentgenogram (PECA Labs, Inc, Pittsburgh, PA
Virtual Stonehenge Reconstruction
No full textVisual and spatial technologies are increasingly revolutionising how archaeology and many other disciplines understand the past in relation to the contemporary world. From digital objects to landscapes, through geophysics, geographical imaging systems and the creation of virtual worlds, new technology provides alternative routes to seeing and understanding both past and present [1]. This research paper describes an interdisciplinary art and design approach to rebuilding and visualising phase 3vi of the Stonehenge site for interactive cultural heritage applications in the 21st Century. A 3D digital research team based at the School of Art, Design & Architecture collaborated with music technologists, sculptors and game designers to gather, interpret, re-imagine and digitally re-model historical and contemporary data on Stonehenge to create a virtual 3D reconstruction of Stonehenge phase 3vi. The researchers discuss the range of digital data, tools, methods used in this phase of the Virtual Stonehenge reconstruction project
Adult to Adult Living Donor Liver Transplantation in Recipients with Low MELD: A Strategy Intended to Overcome Donor Shortage
No full textRecent series have demonstrated advantages of living donor over deceased donor liver transplantation, with particular benefit for those with low model for end-stage liver disease score. The logic underlying the transplantation of patients before they become too sick is intuitive. It reduces mortality and drop outs from the waiting list and makes transplant surgery less demanding. Those principles have to be balanced with donor safety and transplant benefit for the recipient avoiding early, futile transplantation. The authors report a case of adult to adult right lobe living donor liver transplantation performed for a recipient affected by primary biliary cirrhosis with MELD score of 15, in a transplant center located in an area of Europe characterized by chronic organ shortage
Delayed management of blunt traumatic aortic injury: open surgical versus endovascular repair.
No full textAbstract
BACKGROUND:
A growing body of evidence has shown that delayed management of traumatic injury of the thoracic aorta determines survival benefits as compared with immediate treatment. However, few data exist comparing outcomes after delayed open surgical or endovascular management. Accordingly, we reviewed our experience with delayed management, stratifying the data according to type of repair; open surgical versus endovascular.
METHODS:
Since 1992, delayed aortic repair has represented our first-line management for all blunt traumatic thoracic aortic injury (BTTAI) patients, except for those who presented with or became unstable due to impending aortic rupture. These patients were converted to urgent primary aortic repair. Thus, between 1992 and 2010, a total of 77 BTTAI patients were managed according to this policy. There were 57 (74%) men having a mean age of 33.4 years. Thirty-one (41.3%) patients underwent open surgical repair (SR), 44 (58.6%) underwent endovascular repair (ER), and 2 died while awaiting aortic repair. At admission, the clinical and trauma characteristics were similar in both groups. The trauma-to-repair time span (in days) was 200 (Q1-Q3: 27 to 340) and 10 (Q1-Q3: 2 to 79) for SR and ER patients, respectively (p = 0.001). Due to unpaired hemodynamic or imaging signs of impending aortic rupture, 15 patients required urgent repair, which was endovascular in 11 (25%) cases and surgical in 4 (12.9%).
RESULTS:
Overall, hospital mortality was 3.9% (n = 3), being 0% in SR patients and 2.3% (n = 1) in ER patients (p = 0.398). No new postoperative paraplegia occurred; a cerebellar stroke occurred in 1 (2.3%) ER patient receiving intentional coverage of the left subclavian artery. During follow-up (96.1% complete at 95 ± 70 months), no late deaths occurred. At 15 years, the estimates of survival and freedom from secondary aortic procedures were 96% and 100%, respectively.
CONCLUSIONS:
Delayed management of traumatic aortic injury was associated with satisfactory short- and long-term results without significant differences between open surgical and endovascular repair. However, the reduced invasiveness of endovascular repair can optimize operative timing allowing prompt aortic repair in unstable patients, earlier repair in stable patients, and, when indicated, easier concomitant non-aortic surgery
Observations of Bºs→ψ(2S)η and Bº(s)→ψ(2S)π+π- decays
No full textFirst observations of the B0s
→ψ(2S)η, B0 →ψ(2S)π
+
π
− and B0s
→ψ(2S)π
+
π
− decays are made
using a dataset corresponding to an integrated luminosity of 1.0 fb−1 collected by the LHCb experiment in
proton–proton collisions at a centre-of-mass energy of
√
s = 7 TeV. The ratios of the branching fractions
of each of the ψ(2S) modes with respect to the corresponding J/ψ decays are
B(B0s
→ψ(2S)η)
÷
B(B0s
→J/ψη)
= 0.83± 0.14 (stat)±0.12 (syst) ±0.02 (B),
;
B(B0→ψ(2S)π
+
π
−
)
÷
B(B0→J/ψπ
+
π
−
)
= 0.56± 0.07 (stat)±0.05 (syst)± 0.01 (B),
;
B(B0s
→ψ(2S)π
+
π
−
)
÷
B(B0s
→J/ψπ
+
π
−
)
= 0.34± 0.04 (stat)±0.03 (syst)± 0.01 (B),
where the third uncertainty corresponds to the uncertainties of the dilepton branching fractions of the J/ψ
and ψ(2S) meson decays
Las curvas de oferta y demanda de Fleeming Jenkin
No full textEditada en la Fundación Empresa PúblicaFleeming Jenkin (1833-1885) fuee el primer británico que dibujó curvas de oferta y
demanda, las analizó como fondones matemáticas y las empleo para abordar problemas
económicos. Célebre ingeniero, efectuó notables aportaciones a la economía, que
fueron en su tiempo poco destacadas. Este artículo revisa el pensamiento de Jenkin,
poniendo el énfasis en su análisis de las tres leyes de la oferta y la demanda, y su aplicación
al mercado de trabajo y a los impuestos, que dio lugar al descubnmiento independiente
de la noción de excedente del consumidor y del productor. El articulo sostiene
que una razón por la que Jenkin no obtuvo el reconocimiento que merecía hie el
trato hostil que le dispensaron Jevons y Marshall, que devaluaron sus decucciones e
insistieron en que se le habían anticipado. El artículo concluye que esta reivindicacion
carece de fundamento.Fleeming Jenkin (1833-1885) was die first person in Britain to draw supply and
demand curves, discussing them as mathematical functions and employing them to study economic problems. A celebrated engineer, he made remarkable contributions to economics, that attracted little attention in his time. This article goes through Jenkin's
thought, emphasizing his analysis of the three laws of supply and demand, and its application
to the labour market and the taxes, that produced the independent discovery
of the notion of consumer and producer surplus. The article holds that a reason why
Jenkin lacked the acknowledgement he deserved lay in the hostile attitude towards him
by Jevons and Marshall, who undervalued his contributions and insisted that they had
anticipated Jenkin. The article concludes that this claim is unfounded.Publicad
Nonlinearity in the Light Processing of the Human Visual System
No full textVisual evoked potentials, i.e responses to visual stimulation as recorded using electroencephalography have indicated the existence of nonlinear behavior of the visual pathway. Nonlinearities and time delay in the visual system play an important role in understanding the complex nature of the visual system. This study investigated the nonlinear interactions and time delay in the visual pathway, using several types of stimulation paradigms. Multisine (i.e sum of multiple sinusoidal signals) and sine light stimulation were presented to healthy participants in order to elicit steady-state visual evoked responses. The recorded signals were analyzed using multi-spectral phase coherence, a novel cross-frequency phase coupling metric, in order to quantify the nonlinear interactions, form a brain map and estimate time delay. Chirp light stimulation (signals with linearly increasing frequencies) was used to elicit visual responses inside a specific frequency range. Time delay was estimated using Fractional Fourier Transformation due to its ability to handle chirps’ non-stationary properties. Brain maps indicated that multisine paradigms elicit more localized nonlinear interactions than chirp paradigms. All sinusoidal stimulation provided clusters of similar time delays. Bisine presented the most distinctive groups, fact that suggests that bisine is able to be used as a distinction measure. Trisine time delay showed the lowest variance, fact that shows more accurate estimation. Chirp time delay presented also small variances but the mean time delay found to be very frequency dependent. To conclude, this study showed that multisine paradigms are suitable to be used to elicit nonlinear responses but time delay may not be sufficient measure to fully describe the visual system
The concept of cone creation to treat isolated tricuspid valve dysplasia and the case of a double-orifice tricuspid valve
No full textObjectives: Isolated tricuspid valve dysplasia is a rare disease characterized by a wide spectrum of possible anomalies. We describe the use of the Cone concept to treat a patient with a double-orifice tricuspid valve with massive regurgitation and severe deficit of coaptation. Methods: Three adult patients with congenital non-Ebstein tricuspid valve anomaly characterized by severe coaptation deficiency underwent tricuspid valve repair applying the Cone technique. In particular, we describe the case of a symptomatic 21-year-old woman with a double-orifice tricuspid valve, with massive regurgitation and severe right ventricular dilatation. The tricuspid valve was transformed from a double-orifice valve into a single-orifice valve. The most superior orifice was opened, and the tissue surrounding the orifice was used to extend the leaflet of the inferior orifice. A Cone was created, and a ring annuloplasty was used to stabilize the result. Results: The patient was discharged home after 7 days with trivial residual tricuspid regurgitation and no significant antegrade gradient. The final coaptation height was 2.8 cm. The cardiothoracic ratio decreased from 0.77 to 0.59 after 2 months, and symptoms promptly improved. Conclusions: Over the past 2 years, we have applied the Cone creation concept to patients with a severely dysplastic tricuspid valve with excellent early results. One patient had a double-orifice tricuspid valve, and a Cone repair concept was adopted anyway. One orifice was sacrificed, and surrounding tissue was used to augment the leaflets of the other orifice. A Cone was created to improve central coaptation with a good initial result
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