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String theory is one of the most active branches of theoretical physics and has the potential to provide a unified description of all known particles and interactions. This book is a systematic introduction to the subject, focused on the detailed description of how string theory is connected to the real world of particle physics. Aimed at graduate students and researchers working in high energy physics, it provides explicit models of physics beyond the Standard Model. No prior knowledge of string theory is required as all necessary material is provided in the introductory chapters. The book provides particle phenomenologists with the information needed to understand string theory model building and describes in detail several alternative approaches to model building, such as heterotic string compactifications, intersecting D-brane models, D-branes at singularities and F-theory.

Imprecise measurement of physical activity variables might attenuate estimates of the beneficial effects of activity on health-related outcomes. We aimed to compare the cardiometabolic risk factor dose-response relationships for physical activity and sedentary behaviour between accelerometer- and questionnaire-based activity measures. Physical activity and sedentary behaviour were assessed in 317 adults by 7-day accelerometry and International Physical Activity Questionnaire (IPAQ). Fasting blood was taken to determine insulin, glucose, triglyceride and total, LDL and HDL cholesterol concentrations and homeostasis model-estimated insulin resistance (HOMA(IR)). Waist circumference, BMI, body fat percentage and blood pressure were also measured. For both accelerometer-derived sedentary time (<100 counts.min(-1)) and IPAQ-reported sitting time significant positive (negative for HDL cholesterol) relationships were observed with all measured risk factors--i.e. increased sedentary behaviour was associated with increased risk (all p ≤ 0.01). However, for HOMA(IR) and insulin the regression coefficients were >50% lower for the IPAQ-reported compared to the accelerometer-derived measure (p<0.0001 for both interactions). The relationships for moderate-to-vigorous physical activity (MVPA) and risk factors were less strong than those observed for sedentary behaviours, but significant negative relationships were observed for both accelerometer and IPAQ MVPA measures with glucose, and insulin and HOMA(IR) values (all p<0.05). For accelerometer-derived MVPA only, additional negative relationships were seen with triglyceride, total cholesterol and LDL cholesterol concentrations, BMI, waist circumference and percentage body fat, and a positive relationship was evident with HDL cholesterol (p = 0.0002). Regression coefficients for HOMA(IR), insulin and triglyceride were 43-50% lower for the IPAQ-reported compared to the accelerometer-derived MVPA measure (all p≤0.01). Using the IPAQ to determine sitting time and MVPA reveals some, but not all, relationships between these activity measures and metabolic and vascular disease risk factors. Using this self-report method to quantify activity can therefore underestimate the strength of some relationships with risk factors.

Background Facial nerve schwannomas (FNSs) are exceedingly rare benign tumors. This study aims to report on a series of excised FNSs, providing clinical information and details on their surgical management, including novel approaches. Methods We retrospectively reviewed patients who underwent surgical excision of FNSs in a private otology clinic and public tertiary referral center. The main outcome measures were facial nerve function, complete tumor removal, postoperative complications, tumor recurrence, and hearing. Results Seventeen patients (10 men and 7 women) with a mean age of 44.23 years (SD, 12.21) underwent surgery during the study period. The most common symptom was facial nerve dysfunction (58.8%). Facial and otoneurologic symptoms (hearing loss, tinnitus, and vertigo) were observed in 88.8% and 77.7% of patients, respectively. The middle cranial fossa (MCF) was the most common approach (six patients, 35.2%), followed by translabyrinthine (TL), transmastoid (TM), and combined TM‐MCF (three patients, 17.6% each). Exclusive endoscopic transcanal suprageniculate (ETS) and mastoid combined with cervical approaches were applied once in two patients, 5.8% each. Total tumor removal was achieved in all cases. No significant postoperative complications were observed. The mean follow‐up period was 193.2 months (SD, 119.5) and no tumor recurrence was observed. Conclusion This study provides further evidence for the safety and efficacy of various surgical approaches for FNS, and incorporates the endoscopic transcanal approach. Level of evidence 4. Facial nerve schwannomas (FNSs) are exceedingly rare benign tumors. This study aims to report on a series of excised FNSs, providing clinical information and details on their surgical management, including novel approaches.

A bstract We propose a new version of the scalar Weak Gravity Conjecture (WGC) which would apply to any scalar field coupled to quantum gravity. For a single scalar it is given by the differential constraint ( V ″) 2 ≤ (2 V ‴ 2 − V ″ V ′′′′) M p 2 , where V is the scalar potential. It corresponds to the statement that self-interactions of a scalar must be stronger than gravity for any value of the scalar field. We find that the solutions which saturate the bound correspond to towers of extremal states with mass m 2 ϕ = m 0 2 / R / m 2 + 1 / nR 2 , with R 2 = e ϕ , consistent with the emergence of an extra dimension at large or small R and the existence of extended objects (strings). These states act as WGC states for the scalar ϕ . It is also consistent with the distance swampland conjecture with a built-in duality symmetry. All of this is remarkable since neither extra dimensions nor string theory are put in the theory from the beginning, but they emerge. This is quite analogous to how the 11-th dimension appears in M-theory from towers of Type IIA solitonic D 0-branes. From this constraint one can derive several swampland conjectures from a single principle. In particular one finds that an axion potential is only consistent if f ≤ M p , recovering a result already conjectured from other arguments. The conjecture has far reaching consequences and applies to several interesting physical systems: i) Among chaotic inflation potentials only those asymptotically linear may survive. ii) If applied to the radion of the circle compactification of the Standard Model to 3D with Dirac neutrinos, the constraint implies that the 4D cosmological constant scale must be larger than the mass of the lightest neutrino, which must be in normal hierarchy. It also puts a constraint on the EW scale, potentially explaining the hierarchy problem. This recovers and improves results already obtained by applying the AdS swampland conjecture, but in a way which is independent from UV physics. iii) It also constraints simplest moduli fixing string models. The simplest KKLT model is compatible with the constraints but the latter may be relevant for some choices of parameters.

BackgroundA pre-emptive transjugular intrahepatic portosystemic shunt (pTIPS) reduces mortality in high-risk patients with cirrhosis (Child-Pugh C/B+active bleeding) with acute variceal bleeding (AVB). Real-life studies point out that <15% of patients eligible for pTIPS ultimately undergo transjugular intrahepatic portosystemic shunt (TIPS) due to concerns about hepatic encephalopathy (HE). The outcome of patients undergoing pTIPS with HE is unknown. We aimed to (1) assess the prevalence of HE in patients with AVB; (2) evaluate the outcome of patients presenting HE at admission after pTIPS; and (3) determine if HE at admission is a risk factor for death and post-TIPS HE.Patients and methodsThis is an observational study including 2138 patients from 34 centres between October 2011 and May 2015. Placement of pTIPS was based on individual centre policy. Patients were followed up to 1 year, death or liver transplantation.Results671 of 2138 patients were considered at high risk, 66 received pTIPS and 605 endoscopic+drug treatment. At admission, HE was significantly more frequent in high-risk than in low-risk patients (39.2% vs 10.6%, p<0.001). In high-risk patients with HE at admission, pTIPS was associated with a lower 1-year mortality than endoscopic+drug (HR 0.374, 95% CI 0.166 to 0.845, p=0.0181). The incidence of HE was not different between patients treated with pTIPS and endoscopic+drug (38.2% vs 38.7%, p=0.9721), even in patients with HE at admission (56.4% vs 58.7%, p=0.4594). Age >56, shock, Model for End-Stage Liver Disease score >15, endoscopic+drug treatment and HE at admission were independent factors of death in high-risk patients.ConclusionpTIPS is associated with better survival than endoscopic treatment in high-risk patients with cirrhosis with variceal bleeding displaying HE at admission.

A bstract The Swampland Distance Conjecture states that at infinite distance in the scalar moduli space an infinite tower of particles become exponentially massless. We study this issue in the context of 4d type IIA and type IIB Calabi-Yau compactifications. We find that for large moduli not only towers of particles but also domain walls and strings become tensionless. We study in detail the case of type IIA and IIB 𝒩 = 1 CY orientifolds and show how for infinite Kähler and/or complex structure moduli towers of domain walls and strings become tensionless, depending on the particular direction in moduli space. For the type IIA case we construct the monodromy orbits of domain walls in detail. We study the structure of mass scales in these limits and find that these towers may occur at the same scale as the fundamental string scale or the KK scale making sometimes difficult an effective field theory description. The structure of IIA and IIB towers are consistent with mirror symmetry, as long as towers of exotic domain walls associated to non-geometric fluxes also appear. We briefly discuss the issue of emergence within this context and the possible implications for 4d vacua.

A bstract By applying the Covariant Entropy Bound (CEB) to an EFT in a box of size 1 / ΛIR one obtains that the UV and IR cut-offs of the EFT are necessarily correlated. We argue that in a theory of Quantum Gravity (QG) one should identify the UV cutoff with the ‘species scale’, and give a general algorithm to calculate it in the case of multiple towers becoming light. One then obtains an upper bound on the characteristic mass scale of the tower in terms of the IR cut-off, given by M tower ≲ Λ IR 2 α D in Planck units, with α D = ( D − 2 + p )/2 p ( D − 1), where p depends on the density of states. Identifying the IR cut-off with a (non-vanishing) curvature in AdS one reproduces the statement of the AdS Distance Conjecture (ADC), also giving an explicit lower bound for the α exponent. In particular, we find that the CEB implies α ≥ 1/2 in any dimension if there is a single KK tower, both in AdS and dS vacua. However values α < 1/2 are allowed if the particle tower is multiple or has a string component. We also consider the CKN constraint coming from avoiding gravitational collapse which further requires in general α ≥ 1/ D for the lightest tower. We analyse the case of the DGKT-CFI class of Type IIA orientifold models and show it has both particle and string towers below the species scale, so that a careful analysis of how the ADC is defined is needed. We find that this class of models obey but do not saturate the CEB. The UV/IR constraints found apply to both AdS and dS vacua. We comment on possible applications of these ideas to the dS Swampland conjecture as well as to the observed dS phase of the universe.

Hepatitis C virus (HCV) cure after all-oral direct-acting antiviral (DAA) therapy greatly improves the liver and immune system. We aimed to assess the impact of this HCV clearance on immune system-related markers in plasma and the gene expression profile in human immunodeficiency virus (HIV)/HCV-coinfected patients with advanced cirrhosis. We performed a prospective study on 33 HIV/HCV-coinfected patients at baseline and 36 weeks after the sustained virological response. Gene expression was evaluated by RNA-seq analysis on peripheral blood mononuclear cells (PBMCs) and plasma biomarkers by multiplex immunoassays. We found a decrease in plasma biomarkers (PD1, PDL1, CXCL10, CXCL8, IL12p70, IL10, and TGFβ) and liver disease markers (stiffness measurement (LSM), hepatic venous pressure gradient (HVPG), and transaminases, among others). Furthermore, decreased plasma levels of CXCL8, CXCL10, IL10, and PD1 were associated with reduced LSM values. We also found two upregulated ( HAS1 and IRG1 ) and 15 downregulated ( CXCL11, CCL8, CCL7, CCL2, ADARB2, RRAD, MX1, SIGLEC1, IFI44L, IFI44, IFI27, IFI6, IFIT3, IFIT1B , and IFIT1 ) genes at the end of follow-up, all interferon-stimulated genes (ISGs) grouped into four pathways (“cytokine-cytokine receptor interaction”, “viral protein interaction with cytokine and cytokine receptor”, “chemokine signaling pathway”, and “hepatitis C”). Additionally, the decrease in most of these ISGs was significantly related to reduced LSM and HVPG values. In conclusion, HIV/HCV-coinfected patients with advanced-HCV-related cirrhosis who eradicated HCV following DAA therapy exhibited an improvement in liver disease markers and a significant decrease in plasma biomarkers and gene expression related to antiviral/inflammatory response, particularly in levels of several chemokines and ISGs.

A bstract It is known that there are AdS vacua obtained from compactifying the SM to 2 or 3 dimensions. The existence of such vacua depends on the value of neutrino masses through the Casimir effect. Using the Weak Gravity Conjecture, it has been recently argued by Ooguri and Vafa that such vacua are incompatible with the SM embedding into a consistent theory of quantum gravity. We study the limits obtained for both the cosmological constant Λ 4 and neutrino masses from the absence of such dangerous 3D and 2D SM AdS vacua. One interesting implication is that Λ 4 is bounded to be larger than a scale of order m ν 4 , as observed experimentally. Interestingly, this is the first argument implying a non-vanishing Λ 4 only on the basis of particle physics, with no cosmological input. Conversely, the observed Λ 4 implies strong constraints on neutrino masses in the SM and also for some BSM extensions including extra Weyl or Dirac spinors, gravitinos and axions. The upper bounds obtained for neutrino masses imply (for fixed neutrino Yukawa and Λ 4 ) the existence of upper bounds on the EW scale. In the case of massive Majorana neutrinos with a see-saw mechanism associated to a large scale M  ≃ 10 10 − 14 GeV and Y ν 1 ≃ 10 −3 , one obtains that the EW scale cannot exceed M EW ≲ 10 2 − 10 4 GeV. From this point of view, the delicate fine-tuning required to get a small EW scale would be a mirage, since parameters yielding higher EW scales would be in the swampland and would not count as possible consistent theories. This would bring a new perspective into the issue of the EW hierarchy.

A bstract We compute the full classical 4d scalar potential of type IIA Calabi-Yau orientifolds in the presence of fluxes and D6-branes. We show that it can be written as a bilinear form V = Z AB ρ A ρ B , where the ρ A are in one-to-one correspondence with the 4-form fluxes of the 4d effective theory. The ρ A only depend on the internal fluxes, the axions and the topological data of the compactification, and are fully determined by the Freed-Witten anomalies of branes that appear as 4d string defects. The quadratic form Z AB only depends on the saxionic partners of these axions. In general, the ρ A can be seen as the basic invariants under the discrete shift symmetries of the 4d effective theory, and therefore the building blocks of any flux-dependent quantity. All these polynomials may be obtained by derivation from one of them, associated to a universal 4-form. The standard N = 1 supergravity flux superpotential is uniquely determined from this master polynomial , and vice versa.