A comparative study of smart THD-based fault protection techniques for distribution networks

The integration of Distributed Generators (DGs) into distribution systems (DSs) leads to more reliable and efficient power delivery for customers. However, the possibility of bi-directional power flow creates new technical problems for protection schemes. This poses a threat to conventional strategies because the relay settings have to be adjusted depending on the network topology and operational mode. As a solution, it is important to develop novel fault protection techniques to ensure reliable protection and avoid unnecessary tripping. In this regard, Total Harmonic Distortion (THD) can be used as a key parameter for evaluating the grid’s waveform quality during fault events. This paper presents a comparison between two DS protection strategies that employ THD levels, estimated amplitude voltages, and zero-sequence components as instantaneous indicators during the faults that function as a kind of fault sensor to detect, identify, and isolate faults. The first method uses a Multiple Second Order Generalized Integrator (MSOGI) to obtain the estimated variables, whereas the second method uses a single SOGI for the same purpose (SOGI-THD). Both methods rely on communication lines between protective devices (PDs) to facilitate coordinated protection. The effectiveness of these methods is assessed by using simulations in MATLAB/Simulink considering various factors such as different types of faults and DG penetrations, different fault resistances and fault locations in the proposed network. Moreover, the performance of these methods is compared with conventional overcurrent and differential protections. The results show that the SOGI-THD method is highly effective in detecting and isolating faults with a time interval of 6–8.5 ms using only three SOGIs while requiring only 447 processor cycles for execution. In comparison to other protection methods, the SOGI-THD method exhibits a faster response time and a lower computational burden. Furthermore, the SOGI-THD method is robust to harmonic distortion, as it considers pre-existing harmonic content before the fault and avoids interference with the fault detection process.Peer ReviewedPostprint (published version

Un esquema conceptual para identificar localidades con poblaciones en riesgo de anemia y desnutrición crónica

Datos nacionales e incluso departamentales de anemia y desnutrición crónica se recolectan con periodicidad. Es raro encontrar datos a nivel municipal del estado nutricional de una población, información necesaria para focalizar intervenciones. Un esquema conceptual se desarrolló, aplicó y válido. Datos bioquímicos (prevalencia departamental de hemoglobina infantil < 11 g/dL), antropométricos (prevalencia departamental de talla/edad infantil < -2 Desviación Estándar) y socioeconómicos (a nivel municipal, índice de intensidad de pobreza ó población bajo la línea de pobreza extrema) se usaron para identificar localidades con riesgo de presentar anemia y desnutrición crónica, en 11 países latinoamericanos. En un sistema de información geográfica, se unificaron datos nutricionales y socioeconómicos a un mismo formato espacial, que representaba una localidad en un determinado departamento de un país. Se ubicaron aquellas localidades donde coincidían alta desnutrición (anemia o crónica) y pobreza. Para la desnutrición crónica, hubo una alta relación de localidades identificadas con el esquema, al compararlas con datos recolectados a nivel municipal (= 66%), mas no cuando se comparó con un método estadístico (0%). Este esquema articulado a un software de mapeo facilitó la identificación de localidades con poblaciones en riesgo a anemia y desnutrición crónica. Es importante validar el esquema con estudios de campo

Access to HIV/STI testing among male and female Venezuelan migrants in Peru: evidence from a nationwide survey

Background: Human immunodeficiency virus (HIV) infection and sexually transmitted infections (STIs) are major global public health issues. Migrants represent a vulnerable group that faces multiple barriers to access to healthcare services, including HIV/STI testing. This study aimed to assess the factors associated with access to HIV/STI testing in male and female Venezuelan migrants in Peru. Methods: This was a cross-sectional study involving secondary data analysis of the 2022 Venezuelan Population Residing in Peru Survey. The study was conducted in the eight most populated cities inhabited by Venezuelan migrants and refugees. For each city, the sampling design was probabilistic, stratified, and independent. The outcome variable was whether participants had access to HIV or other STI testing during their stay in Peru. Statistical analysis was stratified by sex owing to potential effect modification. Crude and adjusted prevalence ratios were calculated using generalized linear models Poisson family with log link function. Confidence intervals were calculated to 95%. Results: A total of 3,723 male and 3,984 female migrants were included. Access to HIV/STI testing among male and female migrants was 19.85% and 25.16%, respectively. Among male migrants, being LGBTI, health insured, and married or cohabiting were associated with increased access to HIV/STI testing. Among females, those aged 18–44 years, those who were married or cohabiting and were health insured, and those residing for more than 1 year in Peru were significantly more likely to have access to HIV/STI testing. Moreover, physical/mental disability and unemployed status were associated with a lower probability of HIV/STI testing in females. Conclusions: Only two in ten Venezuelan migrants and refugees in Peru were screened for HIV/STI, with fewer males than females. Sex-specific sociodemographic, health-related, and migration-related variables were independently associated with access to HIV/STI testing

Spatial and socioeconomic inequalities in the access to safe drinking water in Peruvian households

"Access to safe drinking water has increased in Peru over the last decades, from 47% (2008) to 52% (2018). Nevertheless, such access would differ according to socioeconomic and regional factors. Thus, this study aimed to assess the socioeconomic inequality in the access to safe drinking water and identify its spatial distribution. We conducted a cross-sectional study based on the secondary data analysis of the 2021 Peruvian Demographic and Health Survey. Access to safe drinking water was a dummy variable categorised as safe if the residual chlorine concentration was 0.5 mg/L. Nationwide, 29.22% of households had access to safe drinking water. A pro-rich inequality in access to safe drinking water was observed. The spatial distribution was clustered. Significant hotspots were found in the south and centre of the country; however, cold spots were found in most areas. SaTScan analysis identified 32 and 63 significant clusters at high and low risks of having access to safe drinking water, respectively. In conclusion, approximately one out of four Peruvian households has access to safe drinking water, which was mostly concentrated among the wealthier households. Intra- and interdepartmental inequalities in access to safe drinking water were found, with several high-risk clusters.

A Secure Cluster-Based Multipath Routing Protocol for WMSNs

The new characteristics of Wireless Multimedia Sensor Network (WMSN) and its design issues brought by handling different traffic classes of multimedia content (video streams, audio, and still images) as well as scalar data over the network, make the proposed routing protocols for typical WSNs not directly applicable for WMSNs. Handling real-time multimedia data requires both energy efficiency and QoS assurance in order to ensure efficient utility of different capabilities of sensor resources and correct delivery of collected information. In this paper, we propose a Secure Cluster-based Multipath Routing protocol for WMSNs, SCMR, to satisfy the requirements of delivering different data types and support high data rate multimedia traffic. SCMR exploits the hierarchical structure of powerful cluster heads and the optimized multiple paths to support timeliness and reliable high data rate multimedia communication with minimum energy dissipation. Also, we present a light-weight distributed security mechanism of key management in order to secure the communication between sensor nodes and protect the network against different types of attacks. Performance evaluation from simulation results demonstrates a significant performance improvement comparing with existing protocols (which do not even provide any kind of security feature) in terms of average end-to-end delay, network throughput, packet delivery ratio, and energy consumption

Housekeeping genes for quantitative expression studies in the three-spined stickleback Gasterosteus aculeatus

Background During the last years the quantification of immune response under immunological challenges, e.g. parasitation, has been a major focus of research. In this context, the expression of immune response genes in teleost fish has been surveyed for scientific and commercial purposes. Despite the fact that it was shown in teleostei and other taxa that the gene for beta-actin is not the most stably expressed housekeeping gene (HKG), depending on the tissue and experimental treatment, the gene has been us Results To establish a reliable method for the measurement of immune gene expression in Gasterosteus aculeatus, sequences from the now available genome database and an EST library of the same species were used to select oligonucleotide primers for HKG, in order to perform quantitative reverse-transcription (RT) PCR. The expression stability of ten candidate reference genes was evaluated in three different tissues, and in five parasite treatment groups, using the three algorithms BestKeeper, geNorm and N Conclusion As they were the most stably expressed genes in all tissues examined, we suggest using the genes for the L13a ribosomal binding protein and ubiquitin as alternative or additional reference genes in expression analysis in Gasterosteus aculeatus.

Prognostic value of neutrophil-to-lymphocyte ratio in COVID-19 patients: A systematic review and meta-analysis

Background: Neutrophil-to-lymphocyte ratio (NLR) is an accessible and widely used biomarker. NLR may be used as an early marker of poor prognosis in patients with COVID-19. Objective: To evaluate the prognostic value of the NLR in patients diagnosed with COVID-19. Methods: We conducted a systematic review and meta-analysis. Observational studies that reported the association between baseline NLR values (ie, at hospital admission) and severity or all-cause mortality in COVID-19 patients were included. The quality of the studies was assessed using the Newcastle-Ottawa Scale (NOS). Random effects models and inverse variance method were used for meta-analyses. The effects were expressed as odds ratios (ORs) and their 95% confidence intervals (CIs). Small study effects were assessed with the Egger's test. Results: We analysed 61 studies (n = 15 522 patients), 58 cohorts, and 3 case-control studies. An increase of one unit of NLR was associated with higher odds of severity (OR 6.22; 95%CI 4.93 to 7.84; P <.001) and higher odds of all-cause mortality (OR 12.6; 95%CI 6.88 to 23.06; P <.001). In our sensitivity analysis, we found that 41 studies with low risk of bias and moderate heterogeneity (I2 = 53% and 58%) maintained strong association between NLR values and both outcomes (severity: OR 5.36; 95% CI 4.45 to 6.45; P <.001; mortality: OR 10.42 95% CI 7.73 to 14.06; P =.005). Conclusions: Higher values of NLR were associated with severity and all-cause mortality in hospitalised COVID-19 patients.Revisión por pare

Vitamin B12 levels in thyroid disorders: A systematic review and meta-analysis

Background and aims: Numerous studies have found an association between vitamin deficiency and thyroid disorders (TD). The presence of anti-parietal cell antibodies is indicative of reduced ability to absorb vitamin B12. Thus, this study reviewed the existing studies with the objective of assessing differences in the serum levels of vitamin B12 among patients with and without TD, the frequency of vitamin B12 deficiency in patients with TD, and the presence of anti-parietal cell antibodies in patients with TD. Methods: A meta-analysis of random-effects model was conducted to calculate pooled frequencies, mean differences (MD), and their respective 95% confidence intervals (CI). We identified 64 studies that met our inclusion criteria (n = 28597). Results: We found that patients with hypothyroidism had lower vitamin B12 levels than healthy participants (MD: −60.67 pg/mL; 95% CI: −107.31 to −14.03 pg/mL; p = 0.01). No significant differences in vitamin B12 levels were observed between healthy participants and patients with hyperthyroidism (p = 0.78), autoimmune thyroid disease (AITD) (p = 0.22), or subclinical hypothyroidism (SH) (p = 0.79). The frequencies of vitamin B12 deficiency among patients with hypothyroidism, hyperthyroidism, SH, and AITD were 27%, 6%, 27%, and 18%, respectively. Conclusions: Patients with hypothyroidism had lower levels of vitamin B12 than healthy participants. No significant differences were observed between vitamin B12 levels and hyperthyroidism, AITD, or SH. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=324422, identifier (CRD42022324422)

Vitamin B12, folate, and homocysteine in metabolic syndrome: a systematic review and meta-analysis

Background & aims: Metabolic syndrome (MetS) is associated with life-threatening conditions. Several studies have reported an association of vitamin B12, folic acid, or homocysteine (Hcy) levels with MetS. This systematic review and meta-analysis assessed the association of vitamin B12, folic acid, and Hcy levels with MetS. Methods: PubMed, Scopus, Embase, Ovid/Medline, and Web of Science were searched up to February 13, 2023. Cross-sectional, case-control, or cohort studies were included. A random-effects model was performed using the DerSimonian and Laird method to estimate the between-study variance. Effect measures were expressed as odds ratios (OR) with their corresponding 95% confidence intervals (95% CI). Between-study heterogeneity was evaluated using Cochran’s Q test and the I2 statistic. Results: Sixty-six articles (n = 87,988 patients) were included. Higher vitamin B12 levels were inversely associated with MetS (OR = 0.87; 95% CI: 0.81–0.93; p < 0.01; I2 = 90%). Higher Hcy levels were associated with MetS (OR = 1.19; 95% CI: 1.14–1.24; p < 0.01; I2 = 90%). Folate levels were not associated with MetS (OR = 0.83; 95% CI: 0.66–1.03; p = 0.09; I2 = 90%). Conclusion: Higher vitamin B12 levels were inversely associated with MetS, whereas higher Hcy levels were associated with MetS. Studies assessing the pathways underlying this association are requiredRevisión por pare