During the early hydration of ordinary Portland cement (OPC), tricalcium aluminate (C3A) exhibits the highest reactivity among the clinker phases. Consequently, C3A significantly influences the early rheological properties of OPC-based materials, thereby linking rheology with C3A reactivity. The reactivity of C3A is affected by temperature, calcium sulfates, admixtures, and ionic strength. Calcium sulfate phases such as gypsum, bassanite, or anhydrite are used in technical Portland cement to control the early reactivity of C3A. This work investigates the impact of three sodium salts - sodium chloride (NaCl), sodium nitrate (NaNO3), and sodium sulfate (Na2SO4) - on the hydration of C3A. We study model suspensions composed of 10% cubic C3A and 90% quartz by weight with in-situ isothermal calorimetry. The C3A suspensions were mixed inside the calorimeter with a water-to-solid ratio of 0.8. Increasing concentrations, i.e., 400, 1000, and 2000 micromol per g, of the sodium salts mentioned above lead to characteristically decreased C3A reactivities. Combined with small amplitude oscillatory shear (SAOS) rheology experiments, we show that the addition of Na2SO4 significantly reduces the heat flow and the initial storage modulus. In contrast, NaNO3 and NaCl had less pronounced effects on both storage modulus and reaction heat. The differences in structure development are attributed to the formation of different hydrate phases. Specifically, Na2SO4 leads to ettringite formation, whereas the presence of nitrate and chloride ions favors the precipitation of AFm phases. The study concludes that introducing various sodium salts can modulate the kinetics of C3A hydration and alter the reaction pathway, forming different hydrate phases.
This research empirically explores how foreign remittances affect Nepal’s economic growth, using annual time-series data covering the period from 2001/02 to 2023/24. As one of the world’s largest recipients of remittances relative to GDP, understanding the role of remittances is crucial for Nepal’s economic policy. The study applies the Autoregressive Distributed Lag (ARDL) model to assess both short-term and long-term relationships. The results reveal a mixed effect: remittances have a statistically significant and positive impact on real GDP in the short run, but this effect becomes insignificant over the long run. On the other hand, gross private capital formation, government expenditure, and exports are found to be strong and significant contributors to long-term economic expansion. The study concludes that while remittances remain an important source of income and stability, excessive reliance on them cannot ensure sustained economic growth. Therefore, policymakers should aim to create a conducive environment for productive investment and strengthen the core drivers of long-term development.
Background: Molestation among adolescents is a growing concern, often underreported due to fear, stigma, and lack of awareness. Adolescents are particularly vulnerable because of their emotional immaturity and limited understanding of personal safety. In India, a high prevalence of child sexual abuse persists despite legal protections such as the POCSO Act. Video Assisted Teaching (VAT) has emerged as an effective educational strategy to improve awareness, empower adolescents, and promote preventive behaviors related to molestation. Objectives: The study aimed to assess the level of knowledge regarding molestation among adolescents in both experimental and control groups before and after the intervention, evaluate the effectiveness of Video Assisted Teaching (VAT) in enhancing knowledge, compare post-test knowledge scores between the two groups, and examine the association between post-test knowledge levels and selected demographic variables. Methods: Aquasi-experimental pretest–post-test control group design was used among 60 adolescents (30 experimental, 30 control) from two selected schools in Guntur, Andhra Pradesh. Participants were selected using simple random sampling. Data were collected using a structured questionnaire before and after VAT intervention in the experimental group. Descriptive and inferential statistics, including t-tests and chi-square tests, were used for analysis. Results: In the experimental group, the mean knowledge score increased from 12.33 (pre-test) to 23.60 (post-test), showing a statistically significant improvement (t = 10.17, p < 0.05). The control group showed no significant change. There was no significant association between post-test knowledge and demographic variables such as age, gender, education level, parental education, family type, or birth order. Conclusion: Video Assisted Teaching was effective in significantly improving adolescents' knowledge regarding molestation. The intervention is recommended for inclusion in school health education programs to enhance awareness, promote self-protection, and reduce abuse risks.
Texto escrito por Saulo Machado Moreira Sousa, Beatriz Fernanda da Silva e Gustavo Martins Rocha, baseado na aula da Dra. Camila Lunardi, Presidente da Abramed, disponível na plataforma SUMMA (Acesse aqui) Esta publicação da SUMMA: Diálogos em Saúde é uma parceria com a Dra. Camila Lunardi, Presidente da Abramed. Apresentamos aprofundamentos e discussões a respeito da Ética Médica, trazendo desde a fundamentação dos Princípios Bioéticos até a aplicação prática no dia a dia do profissional médico, focando no contexto da Emergência Médica e finalizando com dois estudos de caso para melhor entendimento da relevância prática do que foi abordado.
Background: Chronic Obstructive Pulmonary Disease (COPD) is a major cause of morbidity and mortality worldwide, often complicated by cardiovascular abnormalities due to pulmonary arterial hypertension (PAH). Electrocardiography (ECG) is a non-invasive tool to assess cardiac changes in COPD patients. Objective: To evaluate the prevalence and types of ECG abnormalities in patients with COPD. Methods: A crosssectional observational study was conducted on 25 COPD patients admitted to a Teritiary care Hospital. COPD diagnosis was conrmed by spirometry (FEV1/FVC ≤ 0.7 and FEV1 < 80% predicted, post-bronchodilator). ECGs were analysed for abnormalities including right axis deviation, P-pulmonale, right bundle branch block (RBBB), and other parameters indicative of right ventricular strain. Results:The most common ECG abnormality was right axis deviation (60%), followed by P-pulmonale (40%) and RBBB (40%). Other ndings included low S-wave amplitude in V5/V6 (<5 mm, 28%), reduced R/S ratio in V5/V6 (<1, 24%), increased R-wave amplitude in V1 (>7 mm, 8%), elevated R/S ratio in V1 (≥1, 32%), and multifocal atrial tachycardia (8%). These ndings suggest signicant right ventricular strain in COPD patients. Conclusion: ECG is a valuable screening tool for detecting cardiac abnormalities in COPD patients, with right axis deviation, P-pulmonale, and RBBB being the most prevalent. Early ECG screening can aid in risk stratication and improve prognostic assessment in COPD management.
