6,447 research outputs found
The t#-property for integral domains
AbstractGeneralizing work of Gilmer and Heinzer, we define a t#-domain to be a domain R in which ⋂M∈M1RM≠⋂M∈M2RM for any two distinct subsets M1 and M2 of the set of maximal t-ideals of R. We provide characterizations of these domains, and we show that polynomial rings over t#-domains are again t#-domains. Finally, we study overrings of t#-domains
Genetic and Neuroanatomical Support for Functional Brain Network Dynamics in Epilepsy
Focal epilepsy is a devastating neurological disorder that affects an
overwhelming number of patients worldwide, many of whom prove resistant to
medication. The efficacy of current innovative technologies for the treatment
of these patients has been stalled by the lack of accurate and effective
methods to fuse multimodal neuroimaging data to map anatomical targets driving
seizure dynamics. Here we propose a parsimonious model that explains how
large-scale anatomical networks and shared genetic constraints shape
inter-regional communication in focal epilepsy. In extensive ECoG recordings
acquired from a group of patients with medically refractory focal-onset
epilepsy, we find that ictal and preictal functional brain network dynamics can
be accurately predicted from features of brain anatomy and geometry, patterns
of white matter connectivity, and constraints complicit in patterns of gene
coexpression, all of which are conserved across healthy adult populations.
Moreover, we uncover evidence that markers of non-conserved architecture,
potentially driven by idiosyncratic pathology of single subjects, are most
prevalent in high frequency ictal dynamics and low frequency preictal dynamics.
Finally, we find that ictal dynamics are better predicted by white matter
features and more poorly predicted by geometry and genetic constraints than
preictal dynamics, suggesting that the functional brain network dynamics
manifest in seizures rely on - and may directly propagate along - underlying
white matter structure that is largely conserved across humans. Broadly, our
work offers insights into the generic architectural principles of the human
brain that impact seizure dynamics, and could be extended to further our
understanding, models, and predictions of subject-level pathology and response
to intervention
Skolem properties, value-functions, and divisorial ideals
AbstractLet D be the ring of integers of a number field K. It is well known that the ring Int(D) = {f ϵ K[X] ¦ f (D) ⊆ D} of integer-valued polynomials on D is a Prüfer domain. Here we study the divisorial ideals of Int(D) and prove in particular that Int(D) has no divisorial prime ideal.We begin with the local case. We show that, if V is a rank-one discrete valuation domain with finite residue field, then the unitary ideals of Int(V) (that is, the ideals containing nonzero constants) are entirely determined by their values on the completion of V. This improves on the Skolem properties which only deal with finitely generated ideals. We then globalize and consider a Dedekind domain D with finite residue fields. We show that a prime ideal of t(D) is invertible if and only if it is divisorial, and also, in the case where the characteristic of D is 0, if and only if it is an upper to zero which is maximal
Towards an ab initio description of the optical spectra of light-harvesting antennae: application to the CP29 complex of photosystem II.
Only going beyond the static crystal picture through molecular dynamics simulations can a realistic excitonic picture of the light-harvesting complex CP29 be obtained using a multiscale polarizable QM/MM approach
Can lymphangiosarcoma be resurrected? A clinicopathological and immunohistochemical study of lymphatic differentiation in 49 angiosarcomas
Mankey C C, McHugh J B, Thomas D G & Lucas D R (2010) Histopathology 56 , 364–371 Can lymphangiosarcoma be resurrected? A clinicopathological and immunohistochemical study of lymphatic differentiation in 49 angiosarcomas The term lymphangiosarcoma has largely been abandoned in the current classification of endothelial neoplasms. Recently, a number of lymphatic-associated antibodies have been developed for immunohistochemistry, which frequently stain angiosarcomas, implying lymphatic or mixed lymphatic and blood vascular differentiation is common. The aim was to investigate further lymphatic antigen expression, and to explore the relation of immunohistochemistry to morphological and clinical findings.Forty-nine angiosarcomas in tissue microarrays were analysed with D2-40 and antibodies to Prox-1 and vascular endothelial growth factor receptor (VEGFR)-3. D2-40 was positive in 53%, Prox-1 in 76%, and VEGFR-3 in 57%. Tumours with features attributable to lymphatic differentiation such as hobnail and kaposiform morphologies were more often positive with these markers, including a statistical association between D2-40 and hobnailing. Ten tumours had features suggestive of lymphatic differentiation, namely well-differentiated histology, interanastomosing channels devoid of red cells, prominent hobnailing, lymphoid aggregates, and multi-antigen expression of D2-40 (100%), Prox-1 (100%) and VEGFR-3 (60%), which might be deserving of the appellation lymphangiosarcoma. Nine were cutaneous scalp/facial tumours in elderly patients and one arose within chronic lymphoedema.Lymphatic differentiation is common in angiosarcoma, certain subsets show greater lymphatic differentiation than others, and lymphangiosarcoma may be defined pathologically, rather than clinically.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78689/1/j.1365-2559.2010.03484.x.pd
Deterministic entanglement and tomography of ion spin qubits
We have implemented a universal quantum logic gate between qubits stored in
the spin state of a pair of trapped calcium 40 ions. An initial product state
was driven to a maximally entangled state deterministically, with 83% fidelity.
We present a general approach to quantum state tomography which achieves good
robustness to experimental noise and drift, and use it to measure the spin
state of the ions. We find the entanglement of formation is 0.54.Comment: 3 figures, 4 pages, footnotes fixe
Long-lived mesoscopic entanglement outside the Lamb-Dicke regime
We create entangled states of the spin and motion of a single Ca
ion in a linear ion trap. The motional part consists of coherent states of
large separation and long coherence time. The states are created by driving the
motion using counterpropagating laser beams. We theoretically study and
experimentally observe the behaviour outside the Lamb-Dicke regime, where the
trajectory in phase space is modified and the coherent states become squeezed.
We directly observe the modification of the return time of the trajectory, and
infer the squeezing. The mesoscopic entanglement is observed up to with coherence time 170 microseconds and mean phonon excitation
\nbar = 16.Comment: 5 pages, 3 figures. Revised version after editor comment
Radiation Dose and Fluoroscopy Time of Endovascular Treatment in Patients with Intracranial Lateral Dural Arteriovenous Fistulae
Purpose. Intracranial lateral dural arteriovenous fistula (LDAVF) represents a specific subtype of cerebrovascular fistulae, harboring a potentially life-threatening risk of brain hemorrhage. Fluoroscopically guided endovascular embolization is the therapeutic gold standard. We provide detailed dosimetry data to suggest novel diagnostic reference levels (DRL).
Methods. Retrospective single-center study of LDAVFs treated between January 2014 and December 2019. Regarding dosimetry, the dose area product (DAP) and fluoroscopy time were analyzed for the following variables: Cognard scale grade, endovascular technique, angiographic outcome, and digital subtraction angiography (DSA) protocol.
Results. A total of 70 patients (19 female, median age 65 years) were included. Total median values for DAP and fluoroscopy time were 325 Gy cm2 (25%/75% percentile: 245/414 Gy cm2) and 110 min (68/142min), respectively. Neither median DAP nor fluoroscopy time were significantly different when comparing low-grade with high-grade LDAVF (Cognard I + IIa versus IIb–V; p > 0.05, each). Transvenous coil embolization yielded the lowest dosimetry values, with significantly lower median values when compared to a combined transarterial/transvenous technique (DAP 290 Gy cm2 versus 388 Gy cm2, p = 0.031; fluoroscopy time 85 min versus 170 min, p = 0.016). A significant positive correlation was found between number of arterial feeders treated by liquid embolization and both DAP (rs = 0.367; p = 0.010) and fluoroscopy time (rs = 0.295; p = 0.040). Complete LDAVF occlusion was associated with transvenous coiling (p = 0.001). A low-dose DSA protocol yielded a 20% reduction of DAP (p = 0.021).
Conclusion. This LDAVF study suggests several local DRLs which varied substantially dependent on the endovascular technique and DSA protocol
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