Tunneling between Multiple Histories as a Solution to the Information Loss Paradox.

The information loss paradox associated with black hole Hawking evaporation is an unresolved problem in modern theoretical physics. In a recent brief essay, we revisited the evolution of the black hole entanglement entropy via the Euclidean path integral (EPI) of the quantum state and allow for the branching of semi-classical histories along the Lorentzian evolution. We posited that there exist at least two histories that contribute to EPI, where one is an information-losing history, while the other is an information-preserving one. At early times, the former dominates EPI, while at the late times, the latter becomes dominant. By doing so, we recovered the essence of the Page curve, and thus, the unitarity, albeit with the turning point, i.e., the Page time, much shifted toward the late time. In this full-length paper, we fill in the details of our arguments and calculations to strengthen our notion. One implication of this modified Page curve is that the entropy bound may thus be violated. We comment on the similarity and difference between our approach and that of the replica wormholes and the islands' conjectures.

Testing Loop Quantum Gravity from Observational Consequences of Nonsingular Rotating Black Holes.

The lack of rotating black hole models, which are typically found in nature, in loop quantum gravity (LQG) substantially hinders the progress of testing LQG from observations. Starting with a nonrotating LQG black hole as a seed metric, we construct a rotating spacetime using the revised Newman-Janis algorithm. The rotating solution is nonsingular everywhere and it reduces to the Kerr black hole asymptotically. In different regions of the parameter space, the solution describes (1) a wormhole without event horizon (which, we show, is almost ruled out by observations), (2) a black hole with a spacelike transition surface inside the event horizon, or (3) a black hole with a timelike transition region inside the inner horizon. It is shown how fundamental parameters of LQG can be constrained by the observational implications of the shadow cast by this object. The causal structure of our solution depends crucially only on the spacelike transition surface of the nonrotating seed metric, while being agnostic about specific details of the latter, and therefore captures universal features of an effective rotating, nonsingular black hole in LQG.

Randomized trial comparing oral sulfate solution with 4-L polyethylene glycol administered in a split dose as preparation for colonoscopy.

BACKGROUND AND AIM: The present study aimed to evaluate the non-inferiority of low-volume oral sulfate solution (OSS) to 4-L polyethylene glycol (PEG) solutions administered in a split-dose regimen as bowel preparation for colonoscopy. The safety and tolerability were also compared between the two regimens. METHODS: In this prospective, randomized, single-blind, active-control, parallel group, and non-inferiority trial, consecutive outpatients and health checkup recipients aged 19-65 years undergoing elective colonoscopy were enrolled to receive OSS or 4-L PEG in a split-dose regimen. The quality of bowel preparation was evaluated using the Boston Bowel Preparation Scale. The occurrence of any adverse events, acceptance, compliance, and satisfaction during bowel preparation were evaluated by participant interviews. RESULTS: Overall, 210 participants were randomized, and 199 were administered by the study agents. Adequate bowel preparation was achieved in 98.0% (97/99) of the OSS group, which was non-inferior to the PEG group (96%; 96/100) with a difference of +2.8% (95% confidence interval; -2.8, +6.8). There were no differences in the incidence of adverse events except for abdominal pain, which was more frequent in the OSS (7.1%, 7/99) than in the PEG (1.0%, 1/100; P = 0.035) group. Acceptance, compliance, and satisfaction were significantly higher in the OSS than in the PEG group (all P < 0.05). CONCLUSIONS: Split-dose OSS was non-inferior to split-dose 4-L PEG with regard to bowel preparation efficacy before colonoscopy in adult outpatients or screening colonoscopy recipients aged ≤65 years with acceptable safety and superior tolerability.

Naked Black Hole Firewalls.

In the firewall proposal, it is assumed that the firewall lies near the event horizon and should not be observable except by infalling observers, who are presumably terminated at the firewall. However, if the firewall is located near where the horizon would have been, based on the spacetime evolution up to that time, later quantum fluctuations of the Hawking emission rate can cause the "teleological" event horizon to have migrated to the inside of the firewall location, rendering the firewall naked. In principle, the firewall can be arbitrarily far outside the horizon. This casts doubt about the notion that firewalls are the "most conservative" solution to the information loss paradox.

Multiple Pyogenic Liver Abscesses Caused by Microperforation of an Idiopathic Cecal Ulcer.

Idiopathic cecal ulcer is a rare disease entity of unknown cause diagnosed by ruling out other known causes of cecal ulceration. The most common complication of an idiopathic cecal ulcer is bleeding; perforation, peritonitis, abscess, and stricture formation have been noted. The authors treated a 53-year-old woman who presented with fever and intermittent right upper quadrant abdominal pain. Multiple pyogenic liver abscess and a solitary cecal ulcer were diagnosed by radiologic, endoscopic, and pathologic examination, followed by laparoscopic cecectomy. After extensive study, we concluded that this patient's liver abscesses were a complication of the idiopathic cecal ulcer. Herein, we report a case of multiple pyogenic liver abscess caused by microperforation of idiopathic cecal ulcer.

A Case of Aerophagia Diagnosed by Multichannel Intraluminal Impedance Monitoring.

Aerophagia is a disorder caused by abnormal accumulation of air in the gastrointestinal tract as a result of repetitive and frequent inflow of air through the mouth. For the diagnosis of this condition, it is difficult to objectively measure the air swallowing. However, multichannel intraluminal impedance monitoring facilitates the differential diagnosis between normal air swallowing and pathologic aerophagia, and can aid in the determination of the frequency and amount of air swallowed. In this report, in addition to a literature review, we describe a case of 36-year-old man with abdominal distension who was diagnosed with aerophagia using esophageal impedance monitoring and was treated with clonazepam.

What are the risk factors for acute suppurative cholangitis caused by common bile duct stones?

BACKGROUND/AIMS: Acute suppurative cholangitis (ASC), a severe form of acute cholangitis, is a life-threatening condition that must be treated with appropriate and timely management. The purpose of this study was to identify the factors that predispose patients to ASC. METHODS: We retrospectively investigated 181 patients (100 men, 81 women; age, 70.66±7.38 years, mean±SD) who were admitted to Wonkwang University Hospital between January 2005 and June 2007 for acute cholangitis with common bile duct (CBD) stones. All patients underwent endoscopic retrograde cholangiopancreatogram to remove the stones. Variables and factors that could be assessed upon admission were analyzed to identify the risk factors for the development of ASC. RESULTS: Of the 181 patients, 44 (24.3%) presented with ASC. On multivariate analysis, the followings were found to be independent risk factors for the development of ASC: impacted common bile duct stone (p=0.010), current smoker status (p=0.008), advanced age (>70 years; p=0.002), and gallstone (p=0.016). The most commonly isolated organisms in bile culture were Enterococcus species, Escherichia coli, and Klebsiella species. CONCLUSIONS: Impacted bile-duct stones, current smoking, advanced age, and gallstones were identified as independent risk factors for the development of ASC in patients with CBD stones. These results suggest that emergency biliary drainage is beneficial in patients with these risk factors.

Clinical usefulness of transpapillary removal of common bile duct stones by frequency doubled double pulse Nd:YAG laser.

AIM: To study the efficacy and the safety of laser lithotripsy without direct visual control by using a balloon catheter in patients with bile duct stones that could not be extracted by standard technique. METHODS: The seventeen patients (7 male and 10 female; mean age 67.8 years) with difficult common bile duct (CBD) stones were not amenable for conventional endoscopic maneuvers such as sphincterotomy and mechanical lithotripsy were included in this study. Laser wavelengths of 532 nm and 1064 nm as a double pulse were applied with pulse energy of 120 mJ. The laser fiber was advanced under fluoroscopic control through the ERCP balloon catheter. Laser lithotripsy was continued until the fragment size seemed to be less than 10 mm. Endoscopic extraction of the stones and fragments was performed with the use of the Dormia basket and balloon catheter. RESULTS: Bile duct clearance was achieved in 15 of 17 patients (88%). The mean number of treatment sessions was 1.7 +/- 0.6. Endoscopic stone removal could not be achieved in 2 patients (7%). Adverse effects were noted in three patients (hemobilia, pancreatitis, and cholangitis). CONCLUSION: The Frequency Doubled Double Pulse Nd:YAG (FREDDY) laser may be an effective and safe technique in treatment of difficult bile duct stones.