2,239 research outputs found
Possible quantum phase-manipulation of a two-leg ladder in mixed-dimensional fermionic cold atoms
The recent realization of mixed-dimensional systems of cold atoms has
attracted much attention from both experimentalists and theorists. Different
effective interactions and novel correlated quantum many-body phases may be
engineered in these systems, with the different phases being tunable via
external parameters. In this article we investigate a two-species Fermi atom
mixture: one species of atom exists in two hyperfine states and is confined to
move in a two-leg ladder, interacting with an on-site interaction, and the
other moves freely in a two dimensional square lattice that contains the
two-leg ladder. The two species of atoms interact via an on-site interaction on
the ladder. In the limit of weak inter-species interactions, the
two-dimensional gas can be integrated out, leading to an effective long-range
mediated interaction in the ladder, generated by to the on-site inter-species
interaction. We show that the form of the mediated interaction can be
controlled by the density of the two-dimensional gas and that it enhances the
charge density wave instability in the two-leg ladder after the renormalization
group transformation. Parameterizing the phase diagram with various
experimentally controllable quantities, we discuss the possible tuning of the
macroscopic quantum many-body phases of the two-leg ladder in this
mixed-dimensional fermionic cold atom system.Comment: 4 pages and 3 figure
Unconventional superconducting phases on a two-dimensional extended Hubbard model
We study the phase diagram of the extended Hubbard model on a two-dimensional
square lattice, including on-site (U) and nearest-neighbor (V) interactions, at
weak couplings. We show that the charge-density-wave phase that is known to
occur at half-filling when 4V > U gives way to a d_{xy} -wave superconducting
instability away from half-filling, when the Fermi surface is not perfectly
nested, and for sufficiently large repulsive and a range of on-site repulsive
interaction. In addition, when nesting is further suppressed and in presence of
a nearest-neighbor attraction, a triplet time-reversal breaking (p_x +
ip_y)-wave pairing instability emerges, competing with the d_{x2+y2} pairing
state that is known to dominate at fillings just slightly away from half. At
even smaller fillings, where the Fermi surface no longer presents any nesting,
the (p_x +ip_y)-wave superconducting phase dominates in the whole regime of
on-site repulsions and nearest-neighbor attractions, while d_{xy}-pairing
occurs in the presence of on-site attraction. Our results suggest that
zero-energy Majorana fermions can be realized on a square lattice in the
presence of a magnetic field. For a system of cold fermionic atoms on a
two-dimensional square optical lattice, both an on-site repulsion and a
nearest-neighbor attraction would be required, in addition to rotation of the
system to create vortices. We discuss possible ways of experimentally
engineering the required interaction terms in a cold atom system
Diversification as a Value-Adding Strategy for Asian REITs: A Myth or Reality?
This study tests the impact of diversification strategies on the cash flows, expenses, risks and returns of REITs in Asia. Hirschman-Herfindahl indices (HHI) are computed based on 2281 properties owned by 63 sample Asian REITs for the periods from 2002 to 2007 to measure the levels of diversification by property type and geographical region. In our empirical tests that use weighted least square regressions, we find no significant effects of diversification by property types on cash flows, expenses and risk premiums of Asian REITs. However, significant variations in expenses and risk premiums of the REITs are explained by a geographical diversification strategy. REITs with assets distributed across different countries incur higher total expenses, interest expenses, general and administrative expenses and capital expenditure. Regionally diversified REITs have higher risk premiums. The results remain unchanged after controlling for country factor and simultaneity between the cash flows, expenses, risk and return variables.Diversification and focus strategies; Asian REITs; Illiquidity premiums
d_{xy}-Density wave in fermion-fermion cold atom mixtures
We study density wave instabilities in a doubly-degenerate Fermi-Fermi
mixture with symmetry on a square lattice. For sufficiently
large on-site inter-species repulsion, when the two species of fermions are
both at half-filling, two conventional (-wave) number density waves are
formed with a -phase difference between them to minimize the inter-species
repulsion. Upon moving one species away from half-filling, an unconventional
density wave with -wave symmetry emerges. When both species are away
from the vicinity of half-filling, superconducting instabilities dominate. We
present results of a functional renormalization-group calculation that maps out
the phase diagram at weak couplings. Also, we provide a simple explanation for
the emergence of the -density wave phase based on a four-patch model.
We find a robust and general mechanism for -density-wave formation that
is related to the shape and size of the Fermi surfaces. The density imbalance
between the two species of fermions in the vicinity of half-filling leads to
phase-space discrepancy for different inter-species Umklapp couplings. Using a
phase space argument for leading corrections in the one-loop renormalization
group approach to fermions, we show that the phase-space discrepancy in our
system causes opposite flows for the two leading intra-species Umklapp
couplings and that this triggers the -density-wave instability.Comment: revised long version; 8 pages, 7 figure
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External Validation of the RESCUE-IHCA Score as a Predictor for In-Hospital Cardiac Arrest Patients Receiving Extracorporeal Cardiopulmonary Resuscitation
Background: Extracorporeal cardiopulmonary resuscitation (ECPR) improves the prognosis of in-hospital cardiac arrest (IHCA). The six-factor RESCUE-IHCA score (resuscitation using ECPR during IHCA) was developed to predict outcomes of post-IHCA ECPR-treated adult patients. Our goal was to validate the score in an Asian medical center with a high volume and experience of ECPR performance and to compare the differences in patient characteristics between the current study and the original cohort in a 2022 observational study.
Method: For this single-center, retrospective cohort study we enrolled 324 ECPR-treated adult IHCA patients. The primary outcome was in-hospital mortality. We used the area under the receiver operating curve (AUROC) to externally validate the RESCUE-IHCA score. The calibration of the model was tested by the decile calibration plot as well as Hosmer–Lemeshow goodness-of-fit with an associated P-value.
Results: Of the 324 participants, 231 (71%) died before hospital discharge. The discriminative performance of the RESCUE-IHCA score was comparable with the originally validated cohort, with an AUC of 0.63. A prolonged duration of cardiac arrest was associated with an increased risk of mortality (odds ratio [OR] 1.02, 95% confidence interval [CI] 1.01–1.03, P = .006). An initial rhythm of ventricular tachycardia (OR 0.14, 95% CI 0.04–0.51, P = .003), ventricular fibrillation (OR 0.11, 95% CI 0.03–0.46, P = .003), and palpable pulse (OR 0.26, 95% CI 0.07–0.92, P = 0.04) were associated with a reduced mortality risk compared to asystole or pulseless electrical activity. In contrast to the original study, age (P = 0.28), resuscitation timing (P = 0.14), disease category (P = 0.18), and pre-existing renal insufficiency (P = 0.12) were not associated with in-hospital death.
Conclusion: In external validation, the RESCUE-IHCA score exhibited performance comparable to its original validation within the single-center population. Further investigation on hospital experience, time-of-day effect, and specific disease categories is warranted to improve the selection criteria for ECPR candidates during IHCA
Prognostic factors associated with the survival of oral and pharyngeal carcinoma in Taiwan
<p>Abstract</p> <p>Background</p> <p>In Taiwan, a distinct ethnic group variation in incidence and mortality rates has been suggested for most carcinomas. Our aim is to identify the role of prognostic factors associated with the survival of oral and pharyngeal carcinoma in Taiwan.</p> <p>Methods</p> <p>Taiwan Cancer Registry records of 9039 subjects diagnosed with oral and pharyngeal carcinoma were analyzed. The population was divided into three ethnic groups by residence, which were Taiwanese aborigines, Hakka and Hokkien communities. Five-year survival rates were estimated by Kaplan-Meier methods. Ethnic curves differed significantly by log-rank test; therefore separate models for Taiwanese aborigines, Hakka and Hokkien were carried out. The Cox multivariate proportional hazards model was used to examine the role of prognostic factors on ethnic survival.</p> <p>Results</p> <p>The five-year survival rates of oral and pharyngeal carcinoma were significantly poorer for Hokkien community (53.9%) and Taiwanese aborigines community (58.1%) compared with Hakka community (60.5%). The adjusted hazard ratio of Taiwanese aborigines versus Hakka was 1.07 (95%CI, 0.86–1.33) for oral and pharyngeal carcinoma mortality, and 1.16 (95%CI, 1.01–1.33) for Hokkien versus Hakka. Males had significantly poor prognosis than females. Subjects with tongue and/or mouth carcinoma presented the worst prognosis, whereas lip carcinoma had the best prognosis. Subjects with verrucous carcinoma had better survival than squamous cell carcinoma. Prognosis was the worst in elderly subjects, and subjects who underwent surgery had the highest survival rate.</p> <p>Conclusion</p> <p>Our study presented that predictive variables in oral and pharyngeal carcinoma survival have been: ethnic groups, period of diagnosis, gender, diagnostic age, anatomic site, morphologic type, and therapy.</p
Mechanism of Evolution Shared by Gene and Language
We propose a general mechanism for evolution to explain the diversity of gene
and language. To quantify their common features and reveal the hidden
structures, several statistical properties and patterns are examined based on a
new method called the rank-rank analysis. We find that the classical
correspondence, "domain plays the role of word in gene language", is not
rigorous, and propose to replace domain by protein. In addition, we devise a
new evolution unit, syllgram, to include the characteristics of spoken and
written language. Based on the correspondence between (protein, domain) and
(word, syllgram), we discover that both gene and language shared a common
scaling structure and scale-free network. Like the Rosetta stone, this work may
help decipher the secret behind non-coding DNA and unknown languages.Comment: 15 pages, 13 figures, 3 tabl
Associations between blood glucose level and outcomes of adult in-hospital cardiac arrest: a retrospective cohort study
Additional file 3: Table S3. Features, interventions, and outcomes of cardiac arrest events stratified by the presence of measurement of blood glucose level after sustained return of spontaneous circulation
Safety, tolerability, and pharmacokinetics of TG-1000, a new molecular entity against influenza virus: first-in-human study
Background: The cap-snatching mechanism of influenza virus mRNA transcription is strongly suppressed by TG-1000, a prodrug rapidly metabolized into TG-0527, is a potent cap-dependent nucleic acid endonuclease inhibitor. Herein, we aimed to assess the safety, tolerability, and pharmacokinetics of TG-1000 in healthy participants and the effect of food on the pharmacokinetics and safety of TG-1000.Method: The study was divided into 2 parts: Part A [Single Ascending-Dose (SAD) study, 10–160 mg] and Part B [Food-Effect (FE) study, 40 mg] were launched sequentially. The study included 66 participants for both investigations. We administered different TG-1000 capsules or placebo doses per the study protocol and collected blood samples for pharmacokinetic assessments at specific times. In plasma, TG-1000 and its active metabolite TG-0527 were assayed, and PK parameters were determined.Results: In SAD, the increase in AUC was less than the proportional increase in dose over the 20–160 mg dose range, while the increase in Cmax was proportional to the increase in dose. In the 10–160 mg dose range, T1/2, λz and Tmax of TG-0527 were dose-independent; and T1/2 and Tmax were within 33.8–39.4 h and 3.02–6 h, respectively. In FE, the AUC0-inf, AUC0-last, and Cmax of TG-0527 decreased by approximately 17.52%, 18.76%, and 41.35%, respectively, and the Tmax delay was around 1.50 h. No serious adverse events occurred during the studies.Conclusion: Overall, TG-1000 was well tolerated and exhibited an acceptable safety and PK profile, supporting further clinical investigation of TG-1000 for the treatment of influenza
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