The Ribes-Zalesskii property of some one relator groups

summary:The profinite topology on any abstract group $G$, is one such that the fundamental system of neighborhoods of the identity is given by all its subgroups of finite index. We say that a group $G$ has the Ribes-Zalesskii property of rank $k$, or is RZ$_{k}$ with $k$ a natural number, if any product $H_{1} H_{2} \cdots H_{k}$ of finitely generated subgroups $H_{1}, H_{2}, \cdots , H_{k}$ is closed in the profinite topology on $G$. And a group is said to have the Ribes-Zalesskii property or is RZ if it is RZ$_{k}$ for any natural number $k$. In this paper we characterize groups which are RZ$_{2}$. Consequently, we obtain condition under which a free product with amalgamation of two RZ$_{2}$ groups is RZ$_{2}$. After observing that the Baumslag-Solitar groups $BS (m, n)$ are RZ$_{2}$ and clearly RZ if $m= n$, we establish some suitable properties on the RZ$_{2}$ property for the case when $m= -n$. Finally, since any group $BS (m, n)$ can be viewed as a HNN-extension, then we point out the Ribes-Zalesskii property of rank two on some HNN-extensions

Validation of the WRF regional climate model over the subregions of Southeast Asia: climatology and interannual variability

This study investigates the capability of a regional climate model in simulating the climate variability over Southeast Asia (SE Asia). The present-day climate, covering the period 1991 to 2015, was dynamically downscaled using the Weather Research and Forecasting (WRF) model with a horizontal resolution of 27 km. The initial and boundary conditions for the WRF model is provided with the European Centre for medium-range weather forecasting (ECMWF) reanalysis (ERA-Interim) data. The model reproduced the mean precipitation climatology as well as the annual cycle. Nevertheless, the model overestimated the boreal summer precipitation over the SE Asian mainland, and underestimated the boreal winter precipitation over the Indonesian region. Model biases are associated with the bias in simulating the vertically integrated moisture fluxes. At an interannual scale, the model shows good performance over the SE Asian mainland and the Philippines in all seasons except for the boreal summer. The influence of El Niño/Southern Oscillation (ENSO) on rainfall over mainland SE Asia and the Philippines during JJA is weak, and the model successfully simulated the weak relationship realistically. In contrast, model interannual variability over the Indonesia region is good only in boreal summer and autumn seasons. This is because the model successfully simulated the significant negative correlation between rainfall and ENSO. The influence of the Indian Ocean Dipole (IOD) is seen only in the boreal autumn over the Indonesian region, and the model reproduced it reasonably well. The improvement in the representation of precipitation anomaly associated with ENSO/IOD is due to reasonably accurate simulation of large-scale circulation over SE Asia

Verbesserte Biomasse-Kochherde – Strategie zur Schadensminderung hinsichtlich Luftverschmutzung von Wohnräumen und der Abholzung von Brennstoffen. Eine Fallstudie aus der Nordwest-Provinz, Kameruns

This thesis seeks to enhance a better understanding of the concept of cookstoves and their associated repercussions on health and the environment. A three tier methodological approach was used in this study. Firstly, questionnaires were distributed in the study areas and results analysed. Secondly, a laboratory based water boiling test was conducted using three stoves (open fire, rocket stove and “skirt” stove) to assess the effect of wood moisture content on combustion and heat transfer efficiencies. Lastly, a simulation model was used to understand the behaviour of key players within the system of cookstoves and indoor air pollution such that setbacks are better understood, controlled or mitigated. Results of the questionnaires showed that the majority of the people in the case study area are not aware of the threats posed by indoor air pollution on health; however, they are willing to accept any innovations that will abate the pending related environmental, social and health crises associated to poor cooking techniques. From the water boiling test, results showed that fuel moisture greatly affects combustion efficiency and heat transfer efficiency. Fuel at 15% moisture produced best results with little particulate matter and carbonmonoxide emissions meanwhile emissions at 5% and 30% moisture were relatively high. The sensitivity model laid down the basis for comparism and control mechanisms for indoor air pollution and deforestation.Diese Doktorarbeit bemüht sich, ein besseres Verständnis des Konzepts von Kochherden und den damit verbundenen Nachteilen für die Gesundheit und die Umgebung aufzuzeigen. In dieser Studie wurde eine dreistufige methodische Vorgehensweise verwendet. Erstens wurden Fragebogen im Studiengebiet verteilt und die Ergebnisse analysiert. Zweitens wurde im Labor ein ,‚Water-boiling-test“ mit drei Kochherden (open fire, rocket stove und skirt stove) durchgeführt, um die Wirkung des Holzfeuchtigkeitsgehaltes auf die Verbrennungs- und Wärmeübertragungsleistung zu bewerten. Zuletzt wurde ein Simulierungsmodell erstellt, um das Verhalten von Schlüsselpersonen innerhalb des Systems von Kochherden und Innenluftverschmutzung dahingehend zu verstehen, dass Rückschläge besser verstanden, kontrolliert oder gelindert werden können. Die Ergebnisse der Umfragen zeigten, dass sich die Mehrheit der Leute im Studiengebiet der Bedrohungen nicht bewusst ist, die durch die Innenluftverschmutzung auf die Gesundheit einwirken; dennoch sind sie bereit, Innovationen zu akzeptieren, die die anstehenden Umwelt-, Sozial- und Gesundheitskrisen mildern, die durch die schlechten Kochtechniken bedingt sind. Der ,,Water-boiling-test“ zeigte, dass die Kraftstofffeuchtigkeit eine außerordentliche Bedeutung für die Verbrennung- und Wärmeübertragungsleistung hat. Der Brennstoff mit einer 15%-tigen Feuchtigkeit ergab die besten Ergebnisse mit wenig erzeugten Feinstaub und Kohlenmonoxidemissionen, währenddessen die Emissionen mit einer 5- und 30%-tigen Feuchtigkeit relativ hoch waren. Das Sensitivitätsmodell stellte die Basis für Vergleiche und Kontrollmechanismen für die Innenluftverschmutzung und Abholzung dar

Youtube Analytics Channel Visualization Results Using Google Data Studio and Klipfolio

Demonstrate the power of Big Data Analytics using Google Analytics as a platform work flow. First open the YouTube channel, then start recording of the channel analytics is done here automatically by Google. This data is exported from YouTube Analytics to Google sheets and then is fed to Google Analytics. After analyzes the data, it is now integrated with Google Data Studio and Klipfolio. Google Data Studio makes use of AI (Artificial Intelligence) insights techniques that can generate artificial intelligence and prediction-based report graphs which can be analyzed by the end user. In the future, not only YouTube, but any Google products or Google service data can be fed to Google Analytics and integrated in Google Data Studio for artificial intelligence based on Big Data Analytics

Evaluation of six high-resolution satellite and ground-based precipitation products over Malaysia

Satellite precipitation products (SPPs) potentially constitute an alternative to sparse rain gauge networks for assessing the spatial distribution of precipitation. However, applications of these products are still limited due to the lack of robust quality assessment. This study compares daily, monthly, seasonal, and annual rainfall amount at 342 rain gauges over Malaysia to estimations using five SPPs (3B42RT, 3B42V7, GPCP-1DD, PERSIANN-CDR, and CMORPH) and a ground-based precipitation product (APHRODITE). The performance of the precipitation products was evaluated from 2003 to 2007 using continuous (RMSE, R-2, ME, MAE, and RB) and categorical (ACC, POD, FAR, CSI, and HSS) statistical approaches. Overall, 3B42V7 and APHRODITE performed the best, while the worst performance was shown by GPCP-1DD. 3B42RT, 3B42V7, and PERSIANN-CDR slightly overestimated observed precipitation by 2%, 4.7%, and 2.1%, respectively. By contrast, APHRODITE and CMORPH significantly underestimated precipitations by 19.7% and 13.2%, respectively, whereas GPCP-1DD only slightly underestimated by 2.8%. All six precipitation products performed better in the northeast monsoon than in the southwest monsoon. The better performances occurred in eastern and southern Peninsular Malaysia and in the north of East Malaysia, which receives higher rainfall during the northeast monsoon, whereas poor performances occurred in the western and dryer Peninsular Malaysia. All precipitation products underestimated the no/tiny (= 20 mm/day) rainfall events, while they overestimated low (1-20 mm/day) rainfall events. 3B42RT and 3B42V7 showed the best ability to detect precipitation amounts with the highest HSS value (0.36). Precipitations during flood events such as those which occurred in late 2006 and early 2007 were estimated the best by 3B42RT and 3B42V7, as shown by an R-2 value ranging from 0.49 to 0.88 and 0.52 to 0.86, respectively. These results on SPPs' uncertainties and their potential controls might allow sensor and algorithm developers to deliver better products for improved rainfall estimation and thus improved watermanagement

A baseline study of tropical phytoplankton abundance and its relationships to the environmental variables in the Terengganu river estuary, Malaysia

Phytoplankton is a vital and important organism as a producer of the primary food supply of the marine and freshwater food webs. This study is conducted to investigate the variability of phytoplankton abundance related to environmental variables in the Terengganu River Estuary, by using statistical analysis. Total of ten water samples were collected, of which three stations were in the estuary and seven stations were in the coastal water. A total of 124 taxa of 55 genera, belonging to six taxonomic classes were observed at the study area. The order of phytoplankton abundance was diatoms > blue-green algae > golden-brown algae > dinofalgellates > green algae > euglenoids. The phytoplankton abundance was higher in the coastal area compared to the estuary, with the maximum density 764.10 cells mL-1 and 157.40 cells mL-1 respectively. It was recorded that 10.96% of the total abundance from the data collection was registered in the estuary, while the remaining 89.04% were logged in the coastal region. The freshwater phytoplankton was dominated by golden-brown algae (Chrysophyceae), while marine phytoplankton was governed by diatoms and blue-green algae. It was observed that the water temperature and salinity were positively correlated with marine phytoplankton but negatively related to freshwater phytoplankton. High levels of water temperature and hypersalinity at the coastal region was observed to enhance the production rate in the coastal region. In contrast, the nutrients were positively related to freshwater phytoplankton, but negatively correlated to the marine phytoplankton, which results in low concentrations of nutrients in the coastal region that could be caused by intensive uptake by the abundance of marine phytoplankton. This study revealed that environmental variables are an important element in determining the phytoplankton community compositions in the tropical region

Impact of misinformation and disinformation on the use of research evidence in Africa : disinfodemic and policy in an African context

The results of this research revealed various cases, actors, origin, impact, and mitigation strategies of mis/ disinformation on the use of research evidence. The COVID-19 global pandemic has revealed the danger of mis/ disinformation with numbers of reported studies from west and central Africa demonstrating significant negative impact on evidence informed policymaking and women’s empowerment. “Evidence hesitancy” can be seen in policy makers, practitioners, and citizens alike. In this study, the underlying reasons for evidence hesitancy are analyzed: mis/disinformation; crises; culture; religion; social media. The study identified strengthening policy makers and researcher’s relationships as a way of institutionalizing research evidence for Evidence-Informed Decision Making (EIDM and EIPM, evidence-based policy-making)

Heatwave impact on mortality and morbidity and associated vulnerable factors : a systematic review protocol

Heatwave can increase the risk for heat-related illnesses and mortality. Many studies showed certain population are vulnerable to heatwave such as elderly, children and low-income households. However, the findings were inconsistent. This study aims to identify the effect of heatwave on the mortality and morbidity and associated vulnerability factors. Five electronic databases (Pubmed, Ebsco Host, WOS, OVID Medline and Scopus) will be the primary searching tools to retrieve relevant literatures. An additional searching tool (Google Scholar) will be used to seek for grey literatures. Selection of literature will be based on the inclusion criteria (empirical full-text article, English language and published between 2010-2021). Two authors will be assigned in each step of the process, starting from screening of the title, abstract and full text based on the inclusion criteria, data extraction and quality appraisal. Mixed-Method Appraisal Tool (MMAT) will be utilized to assess the quality of selected articles. Meta-analysis, thematic analysis and narrative approach will be the option used to describe the findings. This study protocol is registered under PROSPERO (CRD42021232847). This study presents a reliable and valid systematic review process that identifies a comprehensive evidence-based information on impacts of heatwave on human health especially upon the vulnerable groups