87 research outputs found
Invariant classification of the rotationally symmetric R-separable webs for the Laplace equation in Euclidean space
An invariant characterization of the rotationally symmetric R-separable webs
for the Laplace equation in Euclidean space is given in terms of invariants and
covariants of a real binary quartic canonically associated to the
characteristic conformal Killing tensor which defines the webs.Comment: 25 pages, recently submitted to the Journal of Mathematical Physic
Prevalence, underlying causes, and preventability of sepsis-associated mortality in US acute care hospitals
Importance: Sepsis is present in many hospitalizations that culminate in death. The contribution of sepsis to these deaths, and the extent to which they are preventable, is unknown.
Objective: To estimate the prevalence, underlying causes, and preventability of sepsis-associated mortality in acute care hospitals.
Design, Setting, and Participants: Cohort study in which a retrospective medical record review was conducted of 568 randomly selected adults admitted to 6 US academic and community hospitals from January 1, 2014, to December 31, 2015, who died in the hospital or were discharged to hospice and not readmitted. Medical records were reviewed from January 1, 2017, to March 31, 2018.
Main Outcomes and Measures: Clinicians reviewed cases for sepsis during hospitalization using Sepsis-3 criteria, hospice-qualifying criteria on admission, immediate and underlying causes of death, and suboptimal sepsis-related care such as inappropriate or delayed antibiotics, inadequate source control, or other medical errors. The preventability of each sepsis-associated death was rated on a 6-point Likert scale.
Results: The study cohort included 568 patients (289 [50.9%] men; mean [SD] age, 70.5 [16.1] years) who died in the hospital or were discharged to hospice. Sepsis was present in 300 hospitalizations (52.8%; 95% CI, 48.6%-57.0%) and was the immediate cause of death in 198 cases (34.9%; 95% CI, 30.9%-38.9%). The next most common immediate causes of death were progressive cancer (92 [16.2%]) and heart failure (39 [6.9%]). The most common underlying causes of death in patients with sepsis were solid cancer (63 of 300 [21.0%]), chronic heart disease (46 of 300 [15.3%]), hematologic cancer (31 of 300 [10.3%]), dementia (29 of 300 [9.7%]), and chronic lung disease (27 of 300 [9.0%]). Hospice-qualifying conditions were present on admission in 121 of 300 sepsis-associated deaths (40.3%; 95% CI 34.7%-46.1%), most commonly end-stage cancer. Suboptimal care, most commonly delays in antibiotics, was identified in 68 of 300 sepsis-associated deaths (22.7%). However, only 11 sepsis-associated deaths (3.7%) were judged definitely or moderately likely preventable; another 25 sepsis-associated deaths (8.3%) were considered possibly preventable.
Conclusions and Relevance: In this cohort from 6 US hospitals, sepsis was the most common immediate cause of death. However, most underlying causes of death were related to severe chronic comorbidities and most sepsis-associated deaths were unlikely to be preventable through better hospital-based care. Further innovations in the prevention and care of underlying conditions may be necessary before a major reduction in sepsis-associated deaths can be achieved
Identifying the orbital angular momentum of light based on atomic ensembles
We propose a scheme to distinguish the orbital angular momentum state of the
Laguerre-Gaussian (LG) beam based on the electromagnetically induced
transparency modulated by a microwave field in atomic ensembles. We show that
the transverse phase variation of a probe beam with the LG mode can be mapped
into the spatial intensity distribution due to the change of atomic coherence
caused by the microwave. The proposal may provide a useful tool for studying
higher-dimensional quantum information based on atomic ensembles.Comment: 4 pages, 4 figure
Reusable Multi-Stage Multi-Secret Sharing Schemes Based on CRT
Three secret sharing schemes that use the Mignotte’ssequence and two secret sharing schemes that use the Asmuth-Bloom sequence are proposed in this paper. All these five secret sharing schemes are based on Chinese Remainder Theorem (CRT) [8]. The first scheme that uses the Mignotte’s sequence is a single secret scheme; the second one is an extension of the first one to Multi-secret sharing scheme. The third scheme is again for the case of multi-secrets but it is an improvement over the second scheme in the sense that it reduces the number of publicvalues. The first scheme that uses the Asmuth-Bloom sequence is designed for the case of a single secret and the second one is an extension of the first scheme to the case of multi-secrets. Novelty of the proposed schemes is that the shares of the participants are reusable i.e. same shares are applicable even with a new secret. Also only one share needs to be kept by each participant even for the muslti-secret sharing scheme. Further, the schemes are capable of verifying the honesty of the participants including the dealer. Correctness of the proposed schemes is discussed and show that the proposed schemes are computationally secure
Characteristics of Deterministic and Stochastic Sandpile Models in a Rotational Sandpile Model
Rotational constraint representing a local external bias generally has
non-trivial effect on the critical behavior of lattice statistical models in
equilibrium critical phenomena. In order to study the effect of rotational bias
in a out of equilibrium situation like self-organized criticality, a new two
state ``quasi-deterministic'' rotational sandpile model is developed here
imposing rotational constraint on the flow of sand grains. An extended set of
new critical exponents are found to characterize the avalanche properties at
the non-equilibrium steady state of the model. The probability distribution
functions are found to obey usual finite size scaling supported by negative
time autocorrelation between the toppling waves. The model exhibits
characteristics of both deterministic and stochastic sandpile models.Comment: 27 pages, 11 figure
Directing cell therapy to anatomic target sites in vivo with magnetic resonance targeting
Cell-based therapy exploits modified human cells to treat diseases but its targeted application
in specific tissues, particularly those lying deep in the body where direct injection is not
possible, has been problematic. Here we use a magnetic resonance imaging (MRI) system to
direct macrophages carrying an oncolytic virus, Seprehvir, into primary and metastatic tumour
sites in mice. To achieve this, we magnetically label macrophages with super-paramagnetic
iron oxide nanoparticles and apply pulsed magnetic field gradients in the direction of the
tumour sites. Magnetic resonance targeting guides macrophages from the bloodstream into
tumours, resulting in increased tumour macrophage infiltration and reduction in tumour
burden and metastasis. Our study indicates that clinical MRI scanners can not only track the
location of magnetically labelled cells but also have the potential to steer them into one or
more target tissues
Structure results for higher order symmetry algebras of 2D classical superintegrable systems
Recently the authors and J.M. Kress presented a special function recurrence
relation method to prove quantum superintegrability of an integrable 2D system
that included explicit constructions of higher order symmetries and the
structure relations for the closed algebra generated by these symmetries. We
applied the method to 5 families of systems, each depending on a rational
parameter k, including most notably the caged anisotropic oscillator, the
Tremblay, Turbiner and Winternitz system and a deformed Kepler-Coulomb system.
Here we work out the analogs of these constructions for all of the associated
classical Hamiltonian systems, as well as for a family including the generic
potential on the 2-sphere. We do not have a proof in every case that the
generating symmetries are of lowest possible order, but we believe this to be
so via an extension of our method.Comment: 23 page
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