16 research outputs found
On AdS7 stability
No full textAdS7 supersymmetric solutions in type IIA have been classified, and they are infinitely many. Moreover, every such solution has a non-supersymmetric sister. In this pa- per, we study the perturbative and non-perturbative stability of these non-supersymmetric solutions, focusing on cases without orientifolds. Perturbatively, we first look at the KK spectrum of spin-2 excitations. This does not exhibit instabilities, but it does show that there is no separation of scales for either the BPS and the non-BPS case, thus proving for supersymmetric AdS7 a well-known recent conjecture. We then use 7d gauged supergravity and a brane polarization computation to access part of the spectrum of KK scalars. The result signals an instability for all non-supersymmetric solutions except those that have a single D8 on each side. We finally look at non-perturbative instabilities, and find that NS5 bubbles make these remaining solutions decay
Derivaciones arteriales temporales en los programas de entrenamiento para los cirujanos generales
No full text: The skills development to address vascular trauma by general surgeons is important in hospitals in countries with a lack of vascular surgeons, so we agree the implementation of training programs in vascular surgery basic techniques for general surgeons. In Peru, through an exploratory survey, 43 public hospitals have at least one vascular surgeon, of which 20 are located in Metropolitan Lima, and 14 of the 26 regions of Peru have at least one public institution with vascular surgery capabilities. We recommend the incorporation of the transient arterial shunt technique as an alternative to vascular anastomosis due to its security and feasibility for general surgeons training programs
Intravascular Ultrasound Imaging and Endovascular Treatment of Left Ventricle Assist Device (HM3) Outflow Graft Obstruction
No full textDoppler Ultrasound Monitoring of Echogenicity in Asymptomatic Subcritical Carotid Stenosis and Assessment of Response to Oral Supplementation of Vitamin K2 (PLAK2 Randomized Controlled Trial)
No full textBackground: Plaque composition may predict the evolution of carotid artery stenosis rather than its sole extent. The grey scale median (GSM) value is a reproducible and standardized value to report plaque echogenicity as an indirect measure of its composition. We monitored plaque composition in asymptomatic subcritical carotid stenosis and evaluated the effect of an oral modulating calcification factor (vitamin K2). Methods: Carotid plaque composition was assessed by GSM value. Monitoring the effects of standard therapy (acetylsalicylic acid and low-medium dosage statin) (acetylsalicylic acid (ASA) arm) or standard therapy plus vitamins K2 oral supplementation (ASA + K2 arm) over a 12 months period was conducted using an ultrasound scan in a prospective, open-label, randomized controlled trial (PLAK2). Results: Sixty patients on low-medium dosage statin therapy were enrolled and randomized (30 per arm) to either ASA + K2 or ASA alone. Thirty-seven patients (61.6%) showed at 12 months a stable plaque with a mean increase in the GSM value in respect to the baseline of 2.6% with no differences between the two study arms (p = 0.66). Fifteen patients (25%) showed an 8% GSM value reduction respect the baseline with no differences between the two study arms (p = 0.99). At multivariable analysis, the adjusted mean (95% confidence interval) GSM change per month from baseline was greater in the ASA + K2 arm (-0.55 points, p = 0.048) compared to ASA alone (-0.18 points, p = 0.529). Conclusions: Carotid plaque composition monitoring through GSM value represents a laborious procedure. Although its use may not be applied to everyday practice, a specific application consists in evaluating the effect of pharmacological therapy on plaque composition. This 12 months randomized trial showed that the majority of subcritical asymptomatic carotid plaque on treatment with low-medium dosage statin presented a stable or increased echogenicity. Although vitamin K2 beyond standard therapy did not determine a significant change in plaque composition, for those who presented with GSM reduction it did enhance a GSM monthly decline
Non-supersymmetric AdS and the swampland
No full textInternational audienceWe discuss infinite families of non-supersymmetric AdS solutions in Type IIB string theory. They are siblings of supersymmetric solutions which are associated with (p, q) 5-brane webs and holographically dual to 5d SCFTs engineered by those brane webs. The non-supersymmetric backgrounds carry identical 5-brane charges and are connected to the supersymmetric ones by RG flows. We study the stability of the non-supersymmetric solutions, identifying perturbative and non-perturbative decay channels for all the backgrounds explicitly available. We also identify likely decay mechanisms for solutions that have not been constructed explicitly but may be expected to exist based on brane web considerations. Finally, we exclude scale separation by constructing universal spin 2 modes with masses comparable to the mass-scale of the cosmological constant
Incidence of deep venous thrombosis in COVID-19 hospitalized patients during the first peak of the Italian outbreak
No full textA high rate of thrombotic events has been reported in COVID-19 population. The study aims to assess the incidence of deep vein thrombosis (DVT) in COVID-19 patients admitted to a single tertiary hospital
On AdS stability
No full textAdS7 supersymmetric solutions in type IIA have been classified, and they are infinitely many. Moreover, every such solution has a non-supersymmetric sister. In this pa- per, we study the perturbative and non-perturbative stability of these non-supersymmetric solutions, focusing on cases without orientifolds. Perturbatively, we first look at the KK spectrum of spin-2 excitations. This does not exhibit instabilities, but it does show that there is no separation of scales for either the BPS and the non-BPS case, thus proving for supersymmetric AdS7 a well-known recent conjecture. We then use 7d gauged supergravity and a brane polarization computation to access part of the spectrum of KK scalars. The result signals an instability for all non-supersymmetric solutions except those that have a single D8 on each side. We finally look at non-perturbative instabilities, and find that NS5 bubbles make these remaining solutions decay.AdS supersymmetric solutions in type IIA have been classified, and they are infinitely many. Moreover, every such solution has a non-supersymmetric sister. In this paper, we study the perturbative and non-perturbative stability of these non-supersymmetric solutions, focusing on cases without orientifolds. Perturbatively, we first look at the KK spectrum of spin-2 excitations. This does not exhibit instabilities, but it does show that there is no separation of scales for either the BPS and the non-BPS case, thus proving for supersymmetric AdS a well-known recent conjecture. We then use 7d gauged supergravity and a brane polarization computation to access part of the spectrum of KK scalars. The result signals an instability for all non-supersymmetric solutions except those that have a single D8 on each side. We finally look at non-perturbative instabilities, and find that NS5 bubbles make these remaining solutions decay
Results from the Multicenter Study on Aortoenteric Fistulization After Stent Grafting of the Abdominal Aorta (MAEFISTO).
No full textOBJECTIVE:
This study investigated the frequency, clinical features, therapeutic options, and results of aortoenteric fistulas (AEFs) developing after endovascular abdominal aortic repair (EVAR).
METHODS:
Eight Italian centers with an EVAR program participated in this retrospective multicenter study and collected data on AEFs that developed after a previous EVAR.
RESULTS:
A total of 3932 patients underwent EVAR between 1997 and 2013 at the participating centers. During the same period, 32 patients presented with an AEF during EVAR follow-up, 21 with original EVAR performed for atherosclerotic aneurysmal disease (ATS group) and 11 with the original EVAR performed for a postsurgical pseudoaneurysm (PSA group). The incidence of AEF development after EVAR was 0.46% in the ATS group and 3.9% in the PSA group. Anastomotic PSA as the indication to EVAR (P < .0001) and urgent/emergency EVAR (P = .01) were significantly associated with AEF development. Median time between EVAR and the AEF diagnosis was 32 months (interquartile range, 11-75 months) for the ATS group and 14 months (interquartile range, 10.5-21.5 months) for the PSA group. Among five AEF patients treated conservatively, two (40%) died, at 7 and 15 months, and the remaining three were alive at a median follow-up of 12 months. The AEF was treated surgically in 27 patients, including aortic stent graft explantation in all cases, in situ aortic reconstruction in 14 (52%), and extra-anatomic bypass in 13 (48%). Perioperative mortality was 37% (10 of 27). No additional aortic-related death was recorded in operated-on patients at a median follow-up of 28 months.
CONCLUSIONS:
Late AEFs rarely occur during EVAR follow-up, but the risk is significantly increased when EVAR is performed for PSA after previous aortic surgery and EVAR is performed as an emergency. Conservative and surgical treatment of post-EVAR AEF are both associated with high mortality. However, beyond the perioperative period, surgical correction of AEFs appears to be durable at midterm follow-up
All AdS7 solutions of type II supergravity
No full textIn M-theory, the only AdS7 supersymmetric solutions are AdS 7 × S 4 and its orbifolds. In this paper, we find and classify new supersymmetric solutions of the type AdS7 × M 3 in type II supergravity. While in IIB none exist, in IIA with Romans mass (which does not lift to M-theory) there are many new ones. We use a pure spinor approach reminiscent of generalized complex geometry. Without the need for any Ansatz, the system determines uniquely the form of the metric and fluxes, up to solving a system of ODEs. Namely, the metric on M 3 is that of an S 2 fibered over an interval; this is consistent with the Sp(1) R-symmetry of the holographically dual (1,0) theory. By including D8 brane sources, one can numerically obtain regular solutions, where topologically M 3 ≅ S 3. © 2014 The Author(s).SCOPUS: ar.jinfo:eu-repo/semantics/publishe
