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Open access

Teresa W. Haynes and Michael A. Henning

Abstract

Let G be a graph with vertex set V and no isolated vertices. A sub-set SV is a semipaired dominating set of G if every vertex in V \ S is adjacent to a vertex in S and S can be partitioned into two element subsets such that the vertices in each subset are at most distance two apart. The semipaired domination number γpr2(G) is the minimum cardinality of a semipaired dominating set of G. We show that if G is a connected graph G of order n ≥ 3, then γpr2(G)23n, and we characterize the extremal graphs achieving equality in the bound.

Open access

Arnfried Kemnitz, Massimiliano Marangio and Margit Voigt

Abstract

A (graph) property 𝒫 is a class of simple finite graphs closed under isomorphisms. In this paper we consider generalizations of sum list colorings of graphs with respect to properties 𝒫.

If to each vertex v of a graph G a list L(v) of colors is assigned, then in an (L, 𝒫)-coloring of G every vertex obtains a color from its list and the subgraphs of G induced by vertices of the same color are always in 𝒫. The 𝒫-sum choice number Xsc𝒫(G) of G is the minimum of the sum of all list sizes such that, for any assignment L of lists of colors with the given sizes, there is always an (L, 𝒫)-coloring of G.

We state some basic results on monotonicity, give upper bounds on the 𝒫-sum choice number of arbitrary graphs for several properties, and determine the 𝒫-sum choice number of specific classes of graphs, namely, of all complete graphs, stars, paths, cycles, and all graphs of order at most 4.

Open access

Anita Villeruša, Daiga Behmane, Uldis Berķis, Anita Kokarēviča and Vinita Cauce

Abstract

Competitiveness as a factor of a company selling its services in the market is becoming more relevant in the healthcare sector. The number of institutions that offer their services to international patients is growing. Research shows that the development of medical tourism is country-specific. The main objective of this publication is to discover positive and negative factors for engagement in the provision of services to non-residents. The data was obtained from a cross-sectional study in which 86 managers of health care institutions in Latvia completed a questionnaire. A total of 80.2% of health care institutions had provided services to non-resident patients in the previous year while 19.8% did so regularly. Institutions mainly used websites to advertise their services. Only a small number of institutions employed a marketing specialist or had a strategy to attract non-resident patients. Heads of institutions pointed to a number of internal and external barriers in this connection, including lack of staff, low motivation, limited language skills, inadequate infrastructure, insufficient state-level support to promote the export of services, the social environment, and problems in the health system itself. The study revealed areas that need to be improved regarding future policies to attract non-resident patients and to increase global competitiveness.

Open access

Július Czap, Peter Šugerek, Stanislav Jendrol’ and Juraj Valiska

Abstract

Let G be a plane graph. Two edges are facially adjacent in G if they are consecutive edges on the boundary walk of a face of G. Given nonnegative integers r, s, and t, a facial [r, s, t]-coloring of a plane graph G = (V,E) is a mapping f : VE → {1, . . ., k} such that |f(v 1) − f(v 2)| ≥ r for every two adjacent vertices v 1 and v 2, |f(e 1) − f(e 2)| ≥ s for every two facially adjacent edges e 1 and e 2, and |f(v) − f(e)| ≥ t for all pairs of incident vertices v and edges e. The facial [r, s, t]-chromatic number ̄ χr,s,t(G) of G is defined to be the minimum k such that G admits a facial [r, s, t]-coloring with colors 1, . . ., k. In this paper we show that ̄ χr,s,t(G) ≤ 3r + 3s + t + 1 for every plane graph G. For some triplets [r, s, t] and for some families of plane graphs this bound is improved. Special attention is devoted to the cases when the parameters r, s, and t are small.

Open access

Natālija Bērziņa-Novikova and Māris Taube

Abstract

Until now, the assessment of health care services provided by psychiatric institutions in Latvia has not been carried out and questionnaires to provide assessment from the patient’s perspective have not been adapted. For this study, a questionnaire that has been validated and successfully employed for several years in Norway was chosen to assess patients’ experience and in a psychiatric inpatient setting. The aim of the study was to determine patients’ satisfaction with the quality of mental health care services in Latvia in the subacute inpatient psychiatric ward in Rīga, adapting during this process the PIPEQ-OS (Psychiatric Inpatient Patient Experience Questionnaire) tool in Latvia. The pilot quantitative study was conducted from June 2016 till February 2017. In the study, an anonymous patient self-assessment questionnaire PIPEQ-OS containing 21 questions was used. During the adaptation process, the questionnaire was translated from English into Latvian and Russian and backwards. The quality and compliance of the translation was subsequently tested in cognitive interviews. During the study, 297 patients were discharged from the unit, and 231 of them completed the questionnaire. 12% of the completed questionnaires were not included in data processing due to being incorrectly filled in. Cognitive interviews with 20 patients were carried out; the average length of an interview was 15 minutes. Overall, the translation of the questionnaire proved to be relevant to the research theme. The subsequent factor analysis revealed three significant factors that reached the Cronbach’s alpha index of 0.7. Further studies using socio-demographic data and based on various inpatient units as well as the comparison of satisfaction indicators across different diagnostic groups are needed.

Open access

Sniedze Laivacuma, Jeļena Eglīte, Aleksejs Derovs and Ludmila Vīksna

Abstract

The aim of this study was to assess the relationship between HLA Class II alleles in two groups of patients in Latvia: patients with cystic and alveolar echinococcosis. The study included 37 patients from the Rīga East Clinical University Hospital with echinococcosis (29 patients with cystic echinococcosis and eight patients with alveolar echinococcosis) and 100 healthy control persons without echinococcosis. HLA Class II allele genotyping was performed using Real-time polymerase chain reaction–sequence specific primer (RT-PCR-SSP). The odds ratios (OR), with 95% confidence intervals (95% CI), were calculated using statistical analysis performed with IBM SPSS Statistics for Windows, Version 22.0, to evaluate the risk of developing the disease in an individual having a particular HLA genotype. In the case of cystic echinococcosis a more severe course of a disease can be anticipated in the presence of HLA-DRB1 alleles *17:01 and *07:01, -DQB1 *03:02, and *03:01, -DQA1*04:01 and haplotypes HLA-DRB1*04:01/-DQB1*03:01/ -DQA1*03:01, HLADRB1*11:01/ -DQB1*03:01 /-DQA1*05:01. However, in the group with alveolar echinococcosis it was associated with the HLA-DRB1 alleles *17:01 and *07:01, -DQB1 *05:01 and haplotypes HLA- DRB1*17:01/-DQB1*02:01-2/-DQA1*01:01, HLA-DRB1*11:01/ -DQB1*03:01/-DQA1*01:03 and HLA-DRB1*11:01/-DQB1*03:01/-DQA1*03:01. HLADRB1*15:01/-DQÂ1*06:02-8/-DQA1*05:01 and HLA-DRB1*13:01/-DQB1*02:01-2/-DQA1*05:01 haplotypes were protective in all patient groups. The limitations of this exploratory study indicate that a broader study needs to be conducted for revealing specific risk and protective HLA Class II haplotypes for patients with cystic and alveolar echinococcosis in Latvia.

Open access

Monta Madelāne, Angelika Krūmiņa, Raimonds Sīmanis, Ģirts Šķenders, Andrejs Ivanovs, Gunta Stūre and Ludmila Vīksna

Abstract

Immune activation in human immunodeficiency virus (HIV) infection is driven by microbial translocation and in HIV patients is one of the contributors to faster progression of liver disease along with increased cell apoptosis. The aim of the study was to compare microbial translocation and apoptosis markers in HIV monoinfected and HIV/hepatitis C virus (HCV) coinfected patients, depending on HIV immune status and antiretroviral treatment (ART). We analysed data for 78 HIV monoinfected and 105 HIV/HCV coinfected patients from the Rīga East University Hospital. Lipopolysaccharide (LPS), endotoxin core antibodies (EndoCAb), cytokeratin 18 (CK18) and cyto-chrome c (Cyt-c) levels were measured. No significant difference in LPS, EndoCAb, Cyt-c levels between HIV and HIV/HCV patients was found. The CK18 level was higher in the HIV/HCV group. Correlation between CD4+ cell count and EndoCAb antibodies was found in HCV positive patients. There was a significant effect of ART on markers for EndoCAb IgA and EndoCAb IgM antibodies in the HIV monoinfected group. Correlation between CD4+ cell count and EndoCAb antibodies and LPS was found in HIV/HCV patients on ART. Coinfection with HCV can lead to more pronounced response in EndoCAb antibody production and higher levels of cell apoptosis markers, despite similar LPS levels. ART has a positive effect on immune activation.

Open access

Anda Kadiša, Zaiga Nora-Krūkle, Simons Švirskis, Pēteris Studers, Irute Girkontaite, Aivars Lejnieks and Modra Murovska

Abstract

Rheumatoid arthritis (RA) is a chronic autoimmune disease that causes erosive changes and ankylosis of joints and may cause internal injuries. Osteoarthritis (OA) is a degenerative process of the articular cartilage. However, inflammatory mediators may play a pivotal role in the initiation and perpetuation of the OA process. It is necessary to continue to study possible factors that may promote the development of the disease. The goal of this study was to evaluate the frequency and activity stage of parvovirus B19 (B19V) and persistent human herpes virus (HHV)-6 and HHV-7 infection in RA and OA patients, and healthy persons, in relation to cytokine levels and presence or absence of viral infections. RA patients with active B19V infection had the highest levels of tumour necrosis factor alpha (TNF-α), which may contribute to the development of RA. In the case of OA, the TNF-α level was higher in patients with active persistent B19V infection, suggesting that B19V reactivation affects also OA. Interleukin (IL)-6, IL-10 and metalloproteinase (MMP)-9 levels were higher in RA patients with latent HHV-6/-7 infection in comparison with active HHV-6/-7 infection, whereas in OA patients levels of all studied cytokines were very variable, ranging from low to high but without significant differences. This suggests that also latent HHV-6 and -7 viral infections can promote development of RA.

Open access

Monika Rosicka

Abstract

For a given graph G = (V;E) and permutation π : VV the prism πG of G is defined as follows: VG) = V (G) ∪ V (G′), where G′ is a copy of G, and E(πG) = E(G) ∪ E(G′) ∪M π, where M π = {uv′ : uV (G); v = π (u)} and v′ denotes the copy of v in G′.

We study and compare the properties of convex and weakly convex dominating sets in prism graphs. In particular, we characterize prism γcon-fixers and -doublers. We also show that the differences γwcon(G) – γwcon(πG) and γwcon (πG) – 2γwcon (G) can be arbitrarily large, and that the convex domination number of πG cannot be bounded in terms of γcon (G).

Open access

Ieva Kalere, Ieva Strēle, Mārtiņš Miglinieks, Ilze Repša, Santa Pildava, Mihails Romanovs, Valdis Pīrāgs and Ilze Konrāde

Abstract

The most common autoimmune disorders with clinically opposite manifestations are hypothyroidism in Hashimoto’s thyroiditis and hyperthyroidism in Graves’ disease. The healthcare burden of thyroid disease is substantial, resulting in substantial health care costs. The aim of the present analysis is to assess the use of thyroid medications in Latvia from 2011 to 2014 by age and gender. Our study used reimbursed medication prescriptions data, collected by the National Health Service of Latvia. The main indicator was the number of prevalent users of thyroid medications each year from 2011 to 2014, stratified by age and gender. From 2011 to 2014, the number of thyroxine users per 100 000 revealed a statistically significant increase in all age and gender groups, except in 0- to 9-year-old girls. The number of Thiamazole users among men increased in the age group from 40 to 89 years and in women age groups above 49 years. Increasing sales of both thyroid hormones and antithyroid medications are also observed in Estonia and Lithuania, indicating that growing thyroid morbidity is an issue in the whole region. The substantial increase in number of patients highlights the necessity for national guidelines on the use of thyroid function tests and standards of medical care.