1,378 research outputs found
Zero-norm states and stringy symmetries
We identify spacetime symmetry charges of 26D open bosonic string theory from
an infinite number of zero-norm states (ZNS) with arbitrary high spin in the
old covariant first quantized string spectrum. We give various evidences to
support this identification. These include massive sigma-model calculation,
Witten string field theory calculation, 2D string theory calculation and, most
importantly, three methods of high-energy stringy scattering amplitude
calculations. The last calculations explicitly prove Gross's conjectures in
1988 on high energy symmetry of string theory.Comment: 6 pages. Talks presented by Jen-Chi Lee at XXVIII Spanish Relativity
Meeting (ERE2005),"A Century of Relativity Physics",Oviedo,Spain,6-10 Sep
2005 and "4th Meeting on constrained Dynamics and Quantum Gravity",Cala
Gonone,Sardinia,Italy,12-16 Sep 2005. To appear in the Journal of Physics:
Conference Serie
UV-finite scalar field theory with unitarity
In this paper we show how to define the UV completion of a scalar field
theory such that it is both UV-finite and perturbatively unitary. In the UV
completed theory, the propagator is an infinite sum of ordinary propagators. To
eliminate the UV divergences, we choose the coefficients and masses in the
propagator to satisfy certain algebraic relations, and define the infinite sums
involved in Feynman diagram calculation by analytic continuation. Unitarity can
be proved relatively easily by Cutkosky's rules. The theory is equivalent to
infinitely many particles with specific masses and interactions. We take the
theory as an example and demonstrate our idea through explicit Feynman
diagram computation.Comment: 14 pages, references adde
Construction of Horizontal Wells in Municipal Solid Waste using a Directional Drill
Horizontal directional drilling (HDD) has been employed in many situations including cable lines under rivers and rehabilitation of pipelines under buildings and busy traffic. Within the context of a municipal landfill site, a by-product of organic waste (leachate) accumulates within an established landfill. Leachate is a liquid produced from the wastes placed inside landfills and rain that percolates through the wastes and reacts with the products of decomposition. This thesis investigates the effectiveness of employing HDD techniques to extract leachate in the municipal landfill application
High-energy zero-norm states and symmetries of string theory
High-energy limit of zero-norm states (HZNS) in the old covariant first
quantized (OCFQ) spectrum of the 26D open bosonic string, together with the
assumption of a smooth behavior of string theory in this limit, are used to
derive infinitely many linear relations among the leading high-energy, fixed
angle behavior of four point functions of different string states. As a result,
ratios among all high-energy scattering amplitudes of four arbitrary string
states can be calculated algebraically and the leading order amplitudes can be
expressed in terms of that of four tachyons as conjectured by Gross in 1988. A
dual calculation can also be performed and equivalent results are obtained by
taking the high-energy limit of Virasoro constraints. Finally, as a consistent
sample calculation, we compute all high-energy scattering amplitudes of three
tachyons and one massive state at the leading order by saddle-point
approximation to justify our results.Comment: 10 pages, no figure, modifications of text and reference
D-Instanton in AdS_5 and Instanton in SYM_4
Following the observation of Banks and Green that the D-instantons in AdS_5
correspond to the instantons in 4-dimensional supersymmetric Yang-Mills theory,
we study in more detail this correspondence for individual instantons. The
supergravity solution for a D-instanton in AdS_5 is found using the ansatz used
previously for D-instantons in flat space. We check that the actions and
supersymmetries match between the D-instanton solution and the Yang-Mills
instanton. Generalizing this result, we propose that any supergravity solution
satisfying the ansatz corresponds to a (anti-)self-dual Yang-Mills
configuration. Using this ansatz a family of identities for correlation
functions in the supersymmetric Yang-Mills theory are derived.Comment: LaTeX, 19 pages, no figure, some typos correcte
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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
Molecular cloning and functional analysis of a necrosis and ethylene inducing protein (NEP) from Ganoderma boninense
Fungal necrosis and ethylene inducing proteins (NEPs) induce cell death and elicit strong immune responses in many crops. In this study, we report the cloning and characterization of a transcript encoding NEP from Ganoderma boninense which belongs to a family of fungi in Ganodermataceae that cause serious infections of
cacao, rubber, tea, coffee and palms. The open reading frame (ORF) encoding NEP inG. boninense(GbNEP) was cloned by 5′and 3’rapid amplification of cDNA ends (RACE) PCR. The transcript abundance of GbNEP increased in fungal culture treated with salicylic acid and jasmonic acid, respectively. The soluble recombinant Gb EP expressed in Escherichia coli BL21(DE3) pLysS was able to induce necrosis in tobacco and tomato but ineffective when applied to oil palm leaves and root tissues. The recombinant GbNEP could induce localized cell death, and production of hydrogen peroxide and superoxide in tobacco leaves. The addition of LaCl3(a calcium channel inhibitor) and EGTA (a Ca2+chelator) to tobacco leaves prior to the challenge with GbNEP significantly reduced the necrosis symptoms indicating that Ca2+is required for the action of GbNEP. In summary, this is the first report of NEP from Ganoderma species which may contribute to further research on the role of GbNEP during disease development
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