Signed degree sets in signed graphs

The set D of distinct signed degrees of the vertices in a signed graph G is called its signed degree set. In this paper, we prove that every non-empty set of positive (negative) integers is the signed degree set of some connected signed graph and determine the smallest possible order for such a signed graph. We also prove that every non-empty set of integers is the signed degree set of some connected signed graph

Imbalances in directed multigraphs

In a directed multigraph, the imbalance of a vertex $v_{i}$ is defined as $b_{v_{i}}=d_{v_{i}}^{+}-d_{v_{i}}^{-}$, where $d_{v_{i}}^{+}$ and $d_{v_{i}}^{-}$ denote the outdegree and indegree respectively of $v_{i}$. We characterize imbalances in directed multigraphs and obtain lower and upper bounds on imbalances in such digraphs. Also, we show the existence of a directed multigraph with a given imbalance set

On Energy, Laplacian Energy and PP-fold Graphs

For a graph $G$ having adjacency spectrum ($A$-spectrum) $\lambda_n\leq\lambda_{n-1}\leq\cdots\leq\lambda_1$ and Laplacian spectrum ($L$-spectrum) $0=\mu_n\leq\mu_{n-1}\leq\cdots\leq\mu_1$, the energy is defined as $E(G)=\sum_{i=1}^{n}|\lambda_i|$ and the Laplacian energy is defined as $LE(G)=\sum_{i=1}^{n}|\mu_i-\frac{2m}{n}|$. In this paper, we give upper and lower bounds for the energy of $KK_n^j,~1\leq j \leq n$ and as a consequence we generalize a result of Stevanovic et al. [More on the relation between Energy and Laplacian energy of graphs, MATCH Commun. Math. Comput. Chem. {\bf 61} (2009) 395-401]. We also consider strong double graph and strong $p$-fold graph to construct some new families of graphs $G$ for which E(G)> LE(G)

Sense of coherence and attrition during four-year follow-up in cohorts of permanent and non-permanent Finnish employees

<p>Abstract</p> <p>Background</p> <p>We studied whether health resources, measured as sense of coherence (SOC), are associated with participation in a follow-up survey among permanent and non-permanent employees who responded at baseline.</p> <p>Methods</p> <p>Of a cohort of 5,981 permanent employees, those who after four years were still in the service of the same employer were asked to participate in a follow-up survey. Another cohort consisted of 2,194 fixed-term and 682 subsidised employees; among these the follow-up survey was posted to those whose addresses were found in the population register. Non-participation was divided into loss to follow-up (i.e., failure to locate the individual, death and, among permanent employees, turnover or exit from labour market) and non-response to the follow-up survey. Logistic regression analyses were used to examine whether the respondents differed from the non-respondents with respect to SOC and other characteristics at baseline.</p> <p>Results</p> <p>Among permanent employees the follow-up survey yielded 3,998 respondents, 1,051 were lost, and 932 did not reply. Among non-permanent employees the follow-up survey yielded 1,563 respondents on initially fixed-term and 467 on subsidised contracts, the corresponding figures for those lost were 145 and 38, and for the non-respondents 486 and 177. Low SOC was associated with lower response rate among fixed-term but not among permanent or subsidised employees. No association was found between SOC and loss to follow-up.</p> <p>Conclusion</p> <p>SOC is a potential source of non-random sample attrition and should be taken into account for when estimating bias due to non-participation in occupational cohorts that include fixed-term employees.</p

Comparison of the temporal release pattern of copeptin with conventional biomarkers in acute myocardial infarction

Background Early detection of acute myocardial infarction (AMI) using cardiac biomarkers of myocardial necrosis remains limited since these biomarkers do not rise within the first hours from onset of AMI. We aimed to compare the temporal release pattern of the C-terminal portion of provasopressin (copeptin) with conventional cardiac biomarkers, including creatine kinase isoenzyme (CK-MB), cardiac troponin T (cTnT), and high-sensitivity cTnT (hs-cTnT), in patients with ST-elevation AMI. Methods We included 145 patients undergoing successful primary percutaneous coronary intervention (PCI) for a first ST-elevation AMI presenting within 12 h of symptom onset. Blood samples were taken on admission and at four time points within the first 24 h after PCI. Results In contrast to all other markers, copeptin levels were already elevated on admission and were higher with a shorter time from symptom onset to reperfusion and lower systolic blood pressure. Copeptin levels peaked immediately after symptom onset at a maximum of 249 pmol/L and normalized within 10 h. In contrast, CK-MB, cTnT, and hs-cTnT peaked after 14 h from symptom onset at a maximum of 275 U/L, 5.75 lg/L, and 4.16 lg/L, respectively, and decreased more gradually. Conclusions Copeptin has a distinct release pattern in patients with ST-elevation AMI, peaking within the first hour after symptom onset before conventional cardiac biomarkers and falling to normal ranges within the first day. Further studies are required to determine the exact role of copeptin in AMI suspects presenting within the first hours after symptom onset

Prevalence of Suspected Nonalcoholic Fatty Liver Disease in Hispanic/Latino Individuals Differs by Heritage

Non-alcoholic fatty liver disease (NAFLD) was shown to disproportionally affect Hispanic persons. We examined the prevalence of suspected NAFLD in Hispanic/Latino persons with diverse backgrounds