The relation between the diagonal entries and the eigenvalues of a symmetric matrix, based upon the sign pattern of its off-diagonal entries

It is known that majorization is a complete description of the relationships between the eigenvalues and diagonal entries of real symmetric matrices. However, for large subclasses of such matrices, the diagonal entries impose much greater restrictions on the eigenvalues. Motivated by previous results about Laplacian eigenvalues, we study here the additional restrictions that come from the off-diagonal sign-pattern classes of real symmetric matrices. Each class imposes additional restrictions. Several results are given for the all nonpositive and all nonnegative classes and for the third class that appears when n = 4. Complete description of the possible relationships are given in low dimensions. (C) 2012 Elsevier Inc. All rights reserved

Nonpositive Eigenvalues of the Adjacency Matrix and Lower Bounds for Laplacian Eigenvalues

Let $NPO(k)$ be the smallest number $n$ such that the adjacency matrix of any undirected graph with $n$ vertices or more has at least $k$ nonpositive eigenvalues. We show that $NPO(k)$ is well-defined and prove that the values of $NPO(k)$ for $k=1,2,3,4,5$ are $1,3,6,10,16$ respectively. In addition, we prove that for all $k \geq 5$, $R(k,k+1) \ge NPO(k) > T_k$, in which $R(k,k+1)$ is the Ramsey number for $k$ and $k+1$, and $T_k$ is the $k^{th}$ triangular number. This implies new lower bounds for eigenvalues of Laplacian matrices: the $k$-th largest eigenvalue is bounded from below by the $NPO(k)$-th largest degree, which generalizes some prior results.Comment: 23 pages, 12 figure

Advanced Solid-State Array Spectrometer (ASAS) data sets from the 1990 field season: A unique look at two forested ecosystems

The Advanced Solid-state Array Spectrometer (ASAS) is a pointable imaging spectrometer which uses a solid-state array to acquire imagery of terrestrial targets in 29 spectral bands from .4 to .8 microns. Performance and calibration of the instrument are described. The ASAS data sets obtained in 1990 provide a unique look at forest canopies from two different forest regions of the North America continent under varying temporal, spectral, and bidirectional conditions. These data sets will be used to study such parameters as the albedo of forest canopies, the dynamics of scene radiation due to factors such as canopy architecture, moisture stress, leaf chemistry, topography, and understory composition

Empirical ugri-UBVRc Transformations for Galaxies

We present empirical color transformations between Sloan Digital Sky Survey ugri and Johnson-Cousins UBVRc photometry for nearby galaxies (D < 11 Mpc). We use the Local Volume Legacy (LVL) galaxy sample where there are 90 galaxies with overlapping observational coverage for these two filter sets. The LVL galaxy sample consists of normal, non-starbursting galaxies. We also examine how well the LVL galaxy colors are described by previous transformations derived from standard calibration stars and model-based galaxy templates. We find significant galaxy color scatter around most of the previous transformation relationships. In addition, the previous transformations show systematic offsets between transformed and observed galaxy colors which are visible in observed color-color trends. The LVL-based $galaxy$ transformations show no systematic color offsets and reproduce the observed color-color galaxy trends.Comment: Accepted for publication in MNRAS (9 pages, 6 figures, 4 tables

Spitzer Local Volume Legacy (LVL) SEDs and Physical Properties

We present the panchromatic spectral energy distributions (SEDs) of the Local Volume Legacy (LVL) survey which consists of 258 nearby galaxies ($D<$11 Mpc). The wavelength coverage spans the ultraviolet to the infrared (1500 $\textrm{\AA}$ to 24 $\mu$m) which is utilized to derive global physical properties (i.e., star formation rate, stellar mass, internal extinction due to dust.). With these data, we find color-color relationships and correlated trends between observed and physical properties (i.e., optical magnitudes and dust properties, optical color and specific star formation rate, and ultraviolet-infrared color and metallicity). The SEDs are binned by different galaxy properties to reveal how each property affects the observed shape of these SEDs. In addition, due to the volume-limited nature of LVL, we utilize the dwarf-dominated galaxy sample to test star formation relationships established with higher-mass galaxy samples. We find good agreement with the star-forming "main-sequence" relationship, but find a systematic deviation in the infrared "main-sequence" at low luminosities. This deviation is attributed to suppressed polycyclic aromatic hydrocarbon (PAH) formation in low metallicity environments and/or the destruction of PAHs in more intense radiation fields occurring near a suggested threshold in sSFR at a value of log($sSFR$) $\sim$ $-$10.2.Comment: Accepted for publication in MNRAS (15 pages, 14 figures, 1 table

The Spitzer Local Volume Legacy (LVL) Global Optical Photometry

We present the global optical photometry of 246 galaxies in the Local Volume Legacy (LVL) survey. The full volume-limited sample consists of 258 nearby (D < 11 Mpc) galaxies whose absolute B-band magnitude span a range of -9.6 < M_B < -20.7 mag. A composite optical (UBVR) data set is constructed from observed UBVR and SDSS ugriz imaging, where the ugriz magnitudes are transformed into UBVR. We present photometry within three galaxy apertures defined at UV, optical, and IR wavelengths. Flux comparisons between these apertures reveal that the traditional optical R25 galaxy apertures do not fully encompass extended sources. Using the larger IR apertures we find color-color relationships where later-type spiral and irregular galaxies tend to be bluer than earlier-type galaxies. These data provide the missing optical emission from which future LVL studies can construct the full panchromatic (UV-optical-IR) spectral energy distributions.Comment: Accepted for publication in MNRAS (9 pages, 5 figures, 5 tables

2007-2008 Master Class - Charles Castleman (Violin)

Charles Castleman Performance (October 6, 2007) - Programhttps://spiral.lynn.edu/conservatory_masterclasses/1115/thumbnail.jp

Postoperative Nausea and Vomiting Implications in Neostigmine versus Sugammadex

Purpose/Background: Postoperative nausea and vomiting (PONV) is a frequent complaint in the postoperative period, which can delay discharge, result in readmission, and increase cost for patients and facilities. Inducing paralysis is common in anesthesia, as is utilizing the drugs neostigmine and sugammadex as reversal agents for non-depolarizing neuromuscular blockers. Many studies are available that compare these two drugs to determine if neostigmine increases the risk of PONV over sugammadex. Sugammadex has a more favorable pharmacologic profile and may improve patient outcomes by reducing PONV. Methods: This review included screening a total of 39 studies and peer-reviewed articles that looked at patients undergoing general anesthesia who received non-depolarizing neuromuscular blockers requiring either neostigmine or sugammadex for reversal, along with their respective PONV rates. 8 articles were included, while 31 articles were removed based on our exclusion criteria. These were published between 2014 and 2020 exclusively. The key words used were “neostigmine”, “sugammadex”, “PONV”, along with combinations “paralytic reversal agents and PONV”. This search was performed on the scholarly database MEDLINE. The data items were PONV rates in neostigmine group, PONV rates in sugammadex group, incidence of postoperative analgesic consumption in neostigmine group, and incidence of postoperative analgesic consumption in sugammadex group. Results: Despite numerical differences being noted in the incidence of PONV with sugammadex over reversal with neostigmine, there did not appear to be any statistically significant data in the multiple peer-reviewed trials included in our review, for not one of the 8 studies concluded that there was a higher incidence of PONV in one drug or the other of an y clinical relevance. Although the side-effect profile tended to be better in the sugammadex group than neostigmine in areas other than PONV, there was not sufficient evidence to conclude that one drug was superior to the other in causing a direct reduction of PONV. Implications for Nursing Practice: There were variable but slight differences noted between both drug groups in PONV rates, but it remained that none of the studies determined it was statically significant or clinically conclusive. This review did, however, note other advantages to sugammadex over neostigmine, including its pharmacologic profile of more efficiently reversing non-depolarizing neuromuscular blocking drugs and its more favorable pharmacokinetics. This lack of statistically significant evidence found within these studies consequentially does not support pharmacologic decision-making of one drug in favor of the other for reducing PONV; therefore, PONV alone is not a sufficient rationale for a provider to justify using one reversal over another at the current time until further research proves otherwise