11 research outputs found
Chasing the cuprates with dilatonic dyons
Magnetic field and momentum dissipation are key ingredients in describing
condensed matter systems. We include them in gauge/gravity and systematically
explore the bottom-up panorama of holographic IR effective field theories based
on bulk Einstein-Maxwell Lagrangians plus scalars. The class of solutions here
examined appear insufficient to capture the phenomenology of charge transport
in the cuprates. We analyze in particular the temperature scaling of the
resistivity and of the Hall angle. Keeping an open attitude, we illustrate weak
and strong points of the approach.Comment: 30 pages, 2 figures, Version to appear in JHE
On ground states of interacting Composite Fermions with spin at half filling
The effects of interactions in a 2D electron system in a strong magnetic
field of two degenerate Landau levels with opposite spins and at filling
factors 1/2 are studied. Using the Chern-Simons gauge transformation, the
system is mapped to Composite Fermions. The fluctuations of the gauge field
induce an effective interaction between the Composite Fermions which can be
attractive in both the particle-particle and in the particle-hole channel. As a
consequence, a spin-singlet (s-wave) ground state of Composite Fermions can
exist with a finite pair-breaking energy gap for particle-particle or
particle-hole pairs. The competition between these two possible ground states
is discussed. For long-range Coulomb interaction the particle-particle state is
favored if the interaction strength is small. With increasing interaction
strength there is a crossover towards the particle-hole state. If the
interaction is short range, only the particle-particle state is possible.Comment: REVTEX; 12 pages, 5 figures; submitted to Phisical Review
Transport of fractional Hall quasiparticles through an antidot
Current statistics of an antidot in the fractional quantum Hall regime is
studied for Laughlin's series. The chiral Luttinger liquid picture of edge
states with a renormalized interaction exponent is adopted. Several
peculiar features are found in the sequential tunneling regime. On one side,
current displays negative differential conductance and double-peak structures
when . On the other side, universal sub-poissonian transport regimes are
identified through an analysis of higher current moments. A comparison between
Fano factor and skewness is proposed in order to clearly distinguish the charge
of the carriers, regardless of possible non-universal interaction
renormalizations. Super-poissonian statistics is obtained in the shot limit for
, and plasmonic effects due to the finite-size antidot are tracked.Comment: accepted for publication in Phys. Rev. B, references adde
Electron conductivity and second generation Composite Fermions
The relation between the conductivity tensors of Composite Fermions and
electrons is extended to second generation Composite Fermions. It is shown that
it crucially depends on the coupling matrix for the Chern-Simons gauge field.
The results are applied to a model of interacting Composite Fermions that can
explain both the anomalous plateaus in spin polarization and the corresponding
maxima in the resistivity observed in recent transport experiments
Textbook outcome in urgent early cholecystectomy for acute calculous cholecystitis: results post hoc of the S.P.Ri.M.A.C.C study
Introduction: A textbook outcome patient is one in which the operative course passes uneventful, without complications, readmission or mortality. There is a lack of publications in terms of TO on acute cholecystitis. Objetive: The objective of this study is to analyze the achievement of TO in patients with urgent early cholecystectomy (UEC) for Acute Cholecystitis. and to identify which factors are related to achieving TO. Materials and methods: This is a post hoc study of the SPRiMACC study. It ́s a prospective multicenter observational study run by WSES. The criteria to define TO in urgent early cholecystectomy (TOUEC) were no 30-day mortality, no 30-day postoperative complications, no readmission within 30 days, and hospital stay ≤ 7 days (75th percentile), and full laparoscopic surgery. Patients who met all these conditions were taken as presenting a TOUEC. Outcomes: 1246 urgent early cholecystectomies for ACC were included. In all, 789 patients (63.3%) achieved all TOUEC parameters, while 457 (36.6%) failed to achieve one or more parameters and were considered non-TOUEC. The patients who achieved TOUEC were younger had significantly lower scores on all the risk scales analyzed. In the serological tests, TOUEC patients had lower values for in a lot of variables than non-TOUEC patients. The TOUEC group had lower rates of complicated cholecystitis. Considering operative time, a shorter duration was also associated with a higher probability of reaching TOUEC. Conclusion: Knowledge of the factors that influence the TOUEC can allow us to improve our results in terms of textbook outcome
Infected pancreatic necrosis: outcomes and clinical predictors of mortality. A post hoc analysis of the MANCTRA-1 international study
: The identification of high-risk patients in the early stages of infected pancreatic necrosis (IPN) is critical, because it could help the clinicians to adopt more effective management strategies. We conducted a post hoc analysis of the MANCTRA-1 international study to assess the association between clinical risk factors and mortality among adult patients with IPN. Univariable and multivariable logistic regression models were used to identify prognostic factors of mortality. We identified 247 consecutive patients with IPN hospitalised between January 2019 and December 2020. History of uncontrolled arterial hypertension (p = 0.032; 95% CI 1.135-15.882; aOR 4.245), qSOFA (p = 0.005; 95% CI 1.359-5.879; aOR 2.828), renal failure (p = 0.022; 95% CI 1.138-5.442; aOR 2.489), and haemodynamic failure (p = 0.018; 95% CI 1.184-5.978; aOR 2.661), were identified as independent predictors of mortality in IPN patients. Cholangitis (p = 0.003; 95% CI 1.598-9.930; aOR 3.983), abdominal compartment syndrome (p = 0.032; 95% CI 1.090-6.967; aOR 2.735), and gastrointestinal/intra-abdominal bleeding (p = 0.009; 95% CI 1.286-5.712; aOR 2.710) were independently associated with the risk of mortality. Upfront open surgical necrosectomy was strongly associated with the risk of mortality (p < 0.001; 95% CI 1.912-7.442; aOR 3.772), whereas endoscopic drainage of pancreatic necrosis (p = 0.018; 95% CI 0.138-0.834; aOR 0.339) and enteral nutrition (p = 0.003; 95% CI 0.143-0.716; aOR 0.320) were found as protective factors. Organ failure, acute cholangitis, and upfront open surgical necrosectomy were the most significant predictors of mortality. Our study confirmed that, even in a subgroup of particularly ill patients such as those with IPN, upfront open surgery should be avoided as much as possible. Study protocol registered in ClinicalTrials.Gov (I.D. Number NCT04747990)
Thrombotic complication in Covid19 non hospitalized patients: an underestimated phenomenon?
Intro Thrombotic complications are quite frequent during SARS-CoV2 infection, especially during severe disease and in hospitalized patients. The incidence in mild disease is not clear and probably few cases have been identified. Case report We reported a case of a 60-year-old man with no previous history admitted in our unit for splenic infarct and a floating clot into the descending aorta without signs of severe disease. Discussion Several mechanisms to clarify prothrombotic state have been described and the exact prevalence of thromboembolic phenomenon is probably underestimated. There is no consensus about the treatment and the indication to prevent these complications in non-hospitalized patients. Conclusion Thrombotic events should be suspected also in fit patients with previous or actual symptoms suggestive for Covid 19 infection. Further analysis should be performed to stratify the risk in non hospitalized patients and the indication for prophylactic treatment
Prediction of morbidity and mortality after early cholecystectomy for acute calculous cholecystitis: results of the S.P.Ri.M.A.C.C. study
BackgroundLess invasive alternatives than early cholecystectomy (EC) for acute calculous cholecystitis (ACC) treatment have been spreading in recent years. We still lack a reliable tool to select high-risk patients who could benefit from these alternatives. Our study aimed to prospectively validate the Chole-risk score in predicting postoperative complications in patients undergoing EC for ACC compared with other preoperative risk prediction models.MethodThe S.P.Ri.M.A.C.C. study is a World Society of Emergency Surgery prospective multicenter observational study. From 1st September 2021 to 1st September 2022, 1253 consecutive patients admitted in 79 centers were included. The inclusion criteria were a diagnosis of ACC and to be a candidate for EC. A Cochran-Armitage test of the trend was run to determine whether a linear correlation existed between the Chole-risk score and a complicated postoperative course. To assess the accuracy of the analyzed prediction models-POSSUM Physiological Score (PS), modified Frailty Index, Charlson Comorbidity Index, American Society of Anesthesiologist score (ASA), APACHE II score, and ACC severity grade-receiver operating characteristic (ROC) curves were generated. The area under the ROC curve (AUC) was used to compare the diagnostic abilities.ResultsA 30-day major morbidity of 6.6% and 30-day mortality of 1.1% were found. Chole-risk was validated, but POSSUM PS was the best risk prediction model for a complicated course after EC for ACC (in-hospital mortality: AUC 0.94, p < 0.001; 30-day mortality: AUC 0.94, p < 0.001; in-hospital major morbidity: AUC 0.73, p < 0.001; 30-day major morbidity: AUC 0.70, p < 0.001). POSSUM PS with a cutoff of 25 (defined in our study as a 'Chole-POSSUM' score) was then validated in a separate cohort of patients. It showed a 100% sensitivity and a 100% negative predictive value for mortality and a 96-97% negative predictive value for major complications.ConclusionsThe Chole-risk score was externally validated, but the CHOLE-POSSUM stands as a more accurate prediction model. CHOLE-POSSUM is a reliable tool to stratify patients with ACC into a low-risk group that may represent a safe EC candidate, and a high-risk group, where new minimally invasive endoscopic techniques may find the most useful field of action.Trial Registration: ClinicalTrial.gov NCT04995380
Timing of Cholecystectomy After Moderate and Severe Acute Biliary Pancreatitis
IMPORTANCE Considering the lack of equipoise regarding the timing of cholecystectomy in patients with moderately severe and severe acute biliary pancreatitis (ABP), it is critical to assess this issue.OBJECTIVE To assess the outcomes of early cholecystectomy (EC) in patients with moderately severe and severe ABP.DESIGN, SETTINGS, AND PARTICIPANTS This cohort study retrospectively analyzed real-life data from the MANCTRA-1 (Compliance With Evidence-Based Clinical Guidelines in the Management of Acute Biliary Pancreatitis) data set, assessing 5304 consecutive patients hospitalized between January 1, 2019, and December 31, 2020, for ABP from 42 countries. A total of 3696 patients who were hospitalized for ABP and underwent cholecystectomy were included in the analysis; of these, 1202 underwent EC, defined as a cholecystectomy performed within 14 days of admission. Univariable and multivariable logistic regression models were used to identify prognostic factors of mortality and morbidity. Data analysis was performed from January to February 2023.MAIN OUTCOMES Mortality and morbidity after EC.RESULTS Of the 3696 patients (mean [SD] age, 58.5 [17.8] years; 1907 [51.5%] female) included in the analysis, 1202 (32.5%) underwent EC and 2494 (67.5%) underwent delayed cholecystectomy (DC). Overall, EC presented an increased risk of postoperative mortality (1.4% vs 0.1%, P <.001) and morbidity (7.7% vs 3.7%, P < .001) compared with DC. On the multivariable analysis, moderately severe and severe ABP were associated with increased mortality (odds ratio [OR], 361.46; 95% CI, 2.28-57 212.31; P = .02) and morbidity (OR, 2.64; 95% CI, 1.35-5.19; P = .005). In patients with moderately severe and severe ABP (n = 108), EC was associated with an increased risk of mortality (16 [15.6%] vs 0 [0%], P < .001), morbidity (30 [30.3%] vs 57 [5.5%], P < .001), bile leakage (2 [2.4%] vs 4 [0.4%], P = .02), and infections (12 [14.6%] vs 4 [0.4%], P < .001) compared with patients with mild ABP who underwent EC. In patients with moderately severe and severe ABP (n = 108), EC was associated with higher mortality (16 [15.6%] vs 2 [1.2%], P < .001), morbidity (30 [30.3%] vs 17 [10.3%], P < .001), and infections (12 [14.6%] vs 2 [1.3%], P < .001) compared with patients with moderately severe and severe ABP who underwent DC. On the multivariable analysis, the patient's age (OR, 1.12; 95% CI, 1.02-1.36; P = .03) and American Society of Anesthesiologists score (OR, 5.91; 95% CI, 1.06-32.78; P = .04) were associated with mortality; severe complications of ABP were associated with increased mortality (OR, 50.04; 95% CI, 2.37-1058.01; P = .01) and morbidity (OR, 33.64; 95% CI, 3.19-354.73; P = .003).CONCLUSIONS AND RELEVANCE This cohort study's findings suggest that EC should be considered carefully in patients with moderately severe and severe ABP, as it was associated with increased postoperative mortality and morbidity. However, older and more fragile patients manifesting severe complications related to ABP should most likely not be considered for EC