Aging and scaling laws in β\beta-hydroquinone-clathrate

The dielectric permittivity of the orientational glass methanol(x=0.73)-$\beta$-hydroquinone-clathrate has been studied as function of temperature and waiting time using different temperature-time-protocols. We study aging, rejuvenation and memory effects in the glassy phase and discuss similarities and differences to aging in spin-glasses. We argue that the diluted methanol-clathrate, although conceptually close to its magnetic pendants, takes an intermediate character between a true spin-glass and a pure random field system

A mean-field monomer-dimer model with attractive interaction. The exact solution

A mean-field monomer-dimer model which includes an attractive interaction among both monomers and dimers is introduced and its exact solution rigorously derived. The Heilmann-Lieb method for the pure hard-core interacting case is used to compute upper and lower bounds for the pressure. The bounds are shown to coincide in the thermodynamic limit for a suitable choice of the monomer density m. The consistency equation characterising m is studied in the phase space (h, J), where h tunes the monomer potential and J the attractive potential. The critical point and exponents are computed and show that the model is in the mean-field ferromagnetic universality class.Comment: 32 pages, 6 figure

Multiple scaling regimes in simple aging models

We investigate aging in glassy systems based on a simple model, where a point in configuration space performs thermally activated jumps between the minima of a random energy landscape. The model allows us to show explicitly a subaging behavior and multiple scaling regimes for the correlation function. Both the exponents characterizing the scaling of the different relaxation times with the waiting time and those characterizing the asymptotic decay of the scaling functions are obtained analytically by invoking a `partial equilibrium' concept.Comment: 4 pages, 3 figure

Aging in K1−x_{1-x}Lix_xTa03_3: a domain growth interpretation

The aging behaviour of the a.c. susceptibility of randomly substituted K$_{1-x}$Li$_x$Ta0$_3$ crystals reveals marked differences with spin-glasses in that cooling rate effects are very important. The response to temperature steps (including temperature cycles) was carefully studied. A model based on thermally activated domain growth accounts for all the experimental results, provided one allows for a large distribution of pinning energies, in such a way that `slow' and `fast' domains coexist. Interesting similarities with deeply supercooled liquids are underlined.Comment: 4 pages. Preprint LPTENS/9820, submitted to Phys. Rev. Let

The Solution of the Deep Boltzmann Machine on the Nishimori Line

The deep Boltzmann machine on the Nishimori line with a finite number of layers is exactly solved by a theorem that expresses its pressure through a finite dimensional variational problem of min–max type. In the absence of magnetic fields the order parameter is shown to exhibit a phase transition whose dependence on the geometry of the system is investigated

Genetic aspects of anti-neutrophil cytoplasmic antibody-associated vasculitis

The genetics of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a complex area of investigation because of the low frequency of AAVs, the rarity of familial cases and the complexity of disease phenotypes. However, recent studies have been able to gather significant numbers of patients, and multicentre collaborative efforts have allowed the performance of two genome-wide association studies (GWASs). Genetic association studies based on candidate gene approaches and the two GWASs have greatly contributed to our current understanding of the genetic basis of AAV. The central role of autoimmunity has been confirmed by the significant association with HLA polymorphisms; interestingly, the three main AAV subtypes are associated with distinct HLA variants, i.e. granulomatosis with polyangiitis (Wegener's GPA) with HLA-DP1, microscopic polyangiitis with HLA-DQ and eosinophilic GPA (Churg-Strauss) with HLA-DRB4. GWASs also revealed that polymorphic variants of genes encoding proteinase 3 (PR3), the predominant antigenic target of ANCA in GPA, and its main inhibitor, alpha-1 antitrypsin, are highly associated with GPA and, even more significantly, with PR3-ANCA positivity (regardless of the clinical diagnosis); this emphasizes the central pathogenic role of PR3 and humoral autoimmunity in PR3-ANCA positive vasculitis. Finally, candidate gene approach studies have shown associations with other variants involved in autoimmunity, such as those belonging to the CTLA-4 and PTPN22 genes, although these findings warrant replication in larger studies. Additional studies are underway to better characterize disease associations within the AAV spectrum, which could provide new pathogenetic clues and possibly new treatment targets

Converted laparoscopic distal pancreatectomy: is there an impact on patient outcome and total cost?

Purpose: Recent studies have reported worse outcomes of converted laparoscopic distal pancreatectomy (CLDP) with respect to total laparoscopic (TLDP) and open (ODP). The aim of the study was to evaluate the impact of conversion on patient outcome and on total cost. Methods: Patients requiring a conversion (CLDP) were compared with both TLDP and ODP patients. The relevant patient- and tumour-related variables were collected for each patient. Both intra and postoperative data were extracted. Propensity score matching (PSM) analysis was carried out to equate the groups compared. Results: Two hundred and five patients underwent DP, 105 (51.2%) ODPs, 81 (39.5%) TLDPs, and 19 (9.3%) CLDPs. After PSM, 19 CLDPs, 38 TLDPs, and 38 ODPs were compared. Patients who underwent CLDP showed a significantly longer operative time (P < 0.001), and an increase in blood loss (P = 0.032) and total cost (P = 0.034) with respect to TLDP, and a significantly longer operative time (P < 0.001), less frequent postoperative morbidity (P = 0.050), and a higher readmission rate (P = 0.035) with respect to ODP. Conclusion: Total laparoscopic pancreatectomy was superior regarding operative findings and total costs with respect to CLDP; ODP showed a higher postoperative morbidity rate and a lower readmission rate with respect to CLDP. However, the reasons for the readmission of patients who underwent CLDP were mainly related to postoperative pancreatic fistula (POPF) grade B which is usually due to pancreas texture. Thus, the majority of distal pancreatectomies can be started using a minimally invasive approach, performing an early conversion if necessary

Unmet needs in ANCA-associated vasculitis: Physicians’ and patients’ perspectives

In recent years, clinical research has increased significantly and therapies for antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis have improved. However, there are still unanswered questions and unmet needs about AAV patients. The purpose of this review is to examine the frontiers of research related to emerging biomarkers eventually predicting relapse, and new therapeutic approaches, not to mention new quality of life assessment tools. Identifying predictors of relapse may help optimize therapeutic strategies, minimize disease recurrence, and reduce treatment-related side effects. In addition, it is important to recognize that patients may suffer long-term consequences of the disease and its treatment, which, although life-saving, is often associated with significant side effects. Our goal, therefore, is to highlight what has been achieved, the pitfalls, and what still needs to be done, comparing the views of physicians and patients

Aging and memory effects in beta-hydrochinone-clathrate

The out-of-equilibrium low-frequency complex susceptibility of the orientational glass methanol(73%)-beta-hydrochinone-clathrate is studied using temperature-stop protocols in aging experiments . Although the material does not have a sharp glass transition aging effects including rejuvenation and memory are found at low temperatures. However, they turn out to be much weaker, however, than in conventional magnetic spin glasses.Comment: 5 pages RevTeX, 6 eps-figures include

Trial sequential meta-analysis of laparoscopic versus open pancreaticoduodenectomy: is it the time to stop the randomization?

Background: The advantages of LPD compared with OPD remain debatable. The study aimed to compare the laparoscopic (LPD) versus open (OPD) for pancreaticoduodenectomy. Methods: A meta-analysis of randomized studies (RCTs) comparing LPD and OPD was made. The results were reported as relative risk (RRs) or mean differences (MDs). The trial sequential analysis was used to test the type I and type II errors defining the required information size (RIS). The primary outcome was mortality, major morbidity, and postoperative pancreatic fistula (POPF). R1 resection, post-pancreatectomy hemorrhage, delayed gastric emptying, biliary fistula, reoperation, readmission, operative time (OT), lymph nodes harvested, and length of stay (LOS) were also studied. Results: Four RCTs, counting 818 patients, were found. The RRs for mortality, major morbidity, and POPF were 1.16, 1.04, and 0.86, without significant differences. The RISs were 35,672, 16,548, and 8206. To confirm this equivalence, at least 34,854, 15,730, and 7338 should be randomized. OT was significantly longer in LPD than OPD, with an MD of 63.22. The LOS was significantly shorter in LPD than in OPD, with − 1.76 days. The RISs were 1297 and 1273, excluding a false-positive result. No significant differences were observed for the remaining endpoints, and RISs suggested that more than 3000 patients should be randomized to confirm the equivalence. Conclusion: The equivalence of LPD and OPD for mortality, major morbidity, and POPF is affected by type II error. The RISs to demonstrate a superiority of one of the two techniques seem unrealistic to obtain