9 research outputs found
Semiclassical relativistic strings in S^5 and long coherent operators in N=4 SYM theory
We consider the low energy effective action corresponding to the 1-loop,
planar, dilatation operator in the scalar sector of N=4 SU(N) SYM theory. For a
general class of non-holomorphic ``long'' operators, of bare dimension L>>1, it
is a sigma model action with 8-dimensional target space and agrees with a limit
of the phase-space string sigma model action describing generic fast-moving
strings in the S^5 part of AdS_5 x S^5. The limit of the string action is taken
in a way that allows for a systematic expansion to higher orders in the
effective coupling . This extends previous work on rigid rotating
strings in S^5 (dual to operators in the SU(3) sector of the dilatation
operator) to the case when string oscillations or pulsations in S^5 are
allowed. We establish a map between the profile of the leading order string
solution and the structure of the corresponding coherent, ``locally BPS'', SYM
scalar operator. As an application, we explicitly determine the form of the
non-holomorphic operators dual to the pulsating strings. Using action--angle
variables, we also directly compute the energy of pulsating solutions,
simplifying previous treatments.Comment: LaTeX, 50 pages, 1 figure. v2: References added, minor corrections.
54 pages. v3: Few changes. One paragraph added at the end of section 3. 55
page
Identification of inappropriate prescribing in a Brazilian nursing home using STOPP/START screening tools and the Beers' Criteria
The objective of this study was to determine the prevalence of Potentially Inappropriate Medication (PIM) use and associated factors, as well as the prevalence of Prescribing Omissions (PO). A cross-sectional study was conducted in a philanthropic Brazilian nursing home involving 46 individuals aged 60 years or older. The following information was collected from medical records and drug prescriptions: gender, age, health conditions and drugs used in the past thirty days. PIM and PO were identified according to the Beers' Criteria and the STOPP/START screening tools. Over one third (37%) of the population used at least one PIM according to the Beers' Criteria (n=17) and 60.9% according to the STOPP tool. A significant association was found between polypharmacy (use of five or more drugs) and use of PIM according to the Beers' Criteria, but not according to the STOPP. Eight residents (17.4%) were exposed to eight PO. This study allowed the diagnosis of a concerning drug utilization profile with use of a high number of PIMs. Thus, there is an evident need to implement strategies for improving geriatric prescription
scGate: marker-based purification of cell types from heterogeneous single-cell RNA-seq datasets.
A common bioinformatics task in single-cell data analysis is to purify a cell type or cell population of interest from heterogeneous datasets. Here we present scGate, an algorithm that automatizes marker-based purification of specific cell populations, without requiring training data or reference gene expression profiles. scGate purifies a cell population of interest using a set of markers organized in a hierarchical structure, akin to gating strategies employed in flow cytometry. scGate outperforms state-of-the-art single-cell classifiers and it can be applied to multiple modalities of single-cell data (e.g. RNA-seq, ATAC-seq, CITE-seq). scGate is implemented as an R package and integrated with the Seurat framework, providing an intuitive tool to isolate cell populations of interest from heterogeneous single-cell datasets.
R package source code and reproducible tutorials are available at https://github.com/carmonalab/scGate.
Supplementary data are available at Bioinformatics online
Non-translation-invariance and the synchronization problem in wavelet sampling
One of the major differences between Paley-Wiener spaces of bandlimited signals and the principal shift-invariant (PSI) spaces of wavelet theory is that the latter, although shift-invariant, are in general not translation-invariant. In this paper we study the extra difficulties non-translation-invariance creates for the sampling theory of PSI and multiresolution spaces. In particular it is shown that sampling in PSI spaces requires an extra initialization step to determine the times at which sampled data is acquired. An algorithm is developed to provide this initialization and its effectiveness shown theoretically and demonstrated on a synthetic data set