Life On Earth
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2022 ◽  
Vol 12 ◽  
Author(s):  
Luise Malik ◽  
Sabrina Hedrich

Biochemical processes are a key element of natural cycles occurring in the environment and enabling life on earth. With regard to microbially catalyzed iron transformation, research predominantly has focused on iron oxidation in acidophiles, whereas iron reduction played a minor role. Microbial conversion of ferric to ferrous iron has however become more relevant in recent years. While there are several reviews on neutrophilic iron reducers, this article summarizes the research on extreme acidophilic iron reducers. After the first reports of dissimilatory iron reduction by acidophilic, chemolithoautotrophic Acidithiobacillus strains and heterotrophic Acidiphilium species, many other prokaryotes were shown to reduce iron as part of their metabolism. Still, little is known about the exact mechanisms of iron reduction in extreme acidophiles. Initially, hypotheses and postulations for the occurring mechanisms relied on observations of growth behavior or predictions based on the genome. By comparing genomes of well-studied neutrophilic with acidophilic iron reducers (e.g., Ferroglobus placidus and Sulfolobus spp.), it became clear that the electron transport for iron reduction proceeds differently in acidophiles. Moreover, transcriptomic investigations indicated an enzymatically-mediated process in Acidithiobacillus ferrooxidans using respiratory chain components of the iron oxidation in reverse. Depending on the strain of At. ferrooxidans, further mechanisms were postulated, e.g., indirect iron reduction by hydrogen sulfide, which may form by disproportionation of elemental sulfur. Alternative scenarios include Hip, a high potential iron-sulfur protein, and further cytochromes. Apart from the anaerobic iron reduction mechanisms, sulfur-oxidizing acidithiobacilli have been shown to mediate iron reduction at low pH (< 1.3) under aerobic conditions. This presumably non-enzymatic process may be attributed to intermediates formed during sulfur/tetrathionate and/or hydrogen oxidation and has already been successfully applied for the reductive bioleaching of laterites. The aim of this review is to provide an up-to-date overview on ferric iron reduction by acidophiles. The importance of this process in anaerobic habitats will be demonstrated as well as its potential for application.


Author(s):  
Melinda Gilhen-Baker ◽  
Valentina Roviello ◽  
Diana Beresford-Kroeger ◽  
Giovanni N. Roviello

AbstractOld forests containing ancient trees are essential ecosystems for life on earth. Mechanisms that happen both deep in the root systems and in the highest canopies ensure the viability of our planet. Old forests fix large quantities of atmospheric CO2, produce oxygen, create micro-climates and irreplaceable habitats, in sharp contrast to young forests and monoculture forests. The current intense logging activities induce rapid, adverse effects on our ecosystems and climate. Here we review large old trees with a focus on ecosystem preservation, climate issues, and therapeutic potential. We found that old forests continue to sequester carbon and fix nitrogen. Old trees control below-ground conditions that are essential for tree regeneration. Old forests create micro-climates that slow global warming and are irreplaceable habitats for many endangered species. Old trees produce phytochemicals with many biomedical properties. Old trees also host particular fungi with untapped medicinal potential, including the Agarikon, Fomitopsis officinalis, which is currently being tested against the coronavirus disease 2019 (COVID-19). Large old trees are an important part of our combined cultural heritage, providing people with aesthetic, symbolic, religious, and historical cues. Bringing their numerous environmental, oceanic, ecological, therapeutic, and socio-cultural benefits to the fore, and learning to appreciate old trees in a holistic manner could contribute to halting the worldwide decline of old-growth forests.


2022 ◽  
Author(s):  
Gilles Clement ◽  
Yoshino Sugita

The acceleration of the head and hip along the x-, y-, and z-axis of 14 healthy subjects was recorded during two sessions of 12 consecutive hours. The magnitude, frequency content, and root mean square of the acceleration signals were used to determine the type of physical activity (sitting, standing, walking, etc.) during normal daily life on Earth. The acceleration signal slope (jerk) was also calculated to assess whether these activities were sufficient to maintain bone mineral density. These measurements indicated that the changes in vertical acceleration experienced by our subjects during normal daily life were presumably sufficient to maintain bone mineral density. However, these changes might not be sufficient for postmenopausal women and astronauts during long-term exposure to weightlessness during spaceflight


2022 ◽  
Author(s):  
Jessica West ◽  
Almudena Azcárate Ortega

Space is increasingly critical to modern life on Earth. But there is growing concern that, as it becomes more economically and strategically important, tensions between different space actors are heightening in a manner that could lead to conflict. The accelerating proliferation of counterspace capabilities, as well as the enactment of national policies that deem space an operational or warfighting domain, underlines the very real nature of threats that exist and highlights the importance of keeping space peaceful. To address these challenges, some experts in space security have called for more robust norms of behaviour in outer space. This report explores the role of norms as a tool for outer space governance, as well as their challenges and limitations.


2022 ◽  
pp. 199-217
Author(s):  
A. S. Maheshwari

Environmental pollution states the toxification by different forms of pollutants in the surroundings. This causes the natural system imbalance and affects the life on earth in different ways. The emissions of pollutants into air result in climate changes. The rising levels of CO2 and other air-polluting gases increase the greenhouse effect which results in temperature elevations and affects global weather patterns. Bill Gates also warned “Climate change is a terrible problem, and it absolutely needs to be solved; it deserves to be a huge priority”. Though climate change and air pollution are closely linked, these are treated as separate problems. Hence, it is aimed to understand the aspects of association between climate change and air pollution in this chapter with the objectives: (i) To know the basics of climate change and air pollution, (ii) To review the active background studies on climate change as well as on air pollution, (iii) To identify the issues, controversies, problems which include the effects of global warming and greenhouse gases followed by the types of air pollutants and its harmful effects, (iv) To find the solutions and recommendations, the discussions are made on climate laws and policies, (v) To retrieve, analyze and store the climate change related information, the description about models, tools and databases are given, (vi) To have a flawless insights on the association of climate change and air pollution, (vii) To exemplify species indicators for the assessment of the effect of air pollution on climate change are also included. As Bernie Sanders said “Climate change is a planetary crisis. We've got to act, and we have to act boldly”.


2021 ◽  
Vol 6 (2) ◽  
pp. 141
Author(s):  
Moh. Ilham Dzikrullah ◽  
Ahmad Syafi'i

<p>Almost every aspect of human life on earth has been disrupted since the emergence of Covid-19, particularly education. Many countries have decided to close schools and universities. This condition has forced the Indonesian government through its Ministry of Education to implement policies moving conventional classrooms to be online classrooms. This process is carried out to maintain the health of students to avoid Covid-19. The learning process can be helped by using one of the applications on the internet which is called Student Response System (SRS). According to the statement, the researcher investigated secondary school students’ perceptions towards the implementation of Quizizz as an assessment platform in teaching English. Mixed-method research has been implemented in this study. The study involved 61 students as the participants in quantitative stage and 6 students in qualitative stage. The main instruments employed in this research are an online questionnaire and in-depth interview. The findings indicated that the students have both positive and negative perceptions toward the use of online assessment, especially in Quizizz. The students enjoyed Quizizz and thought it was exciting, interesting, motivating, and enjoyable because the Quizizz platform was distinct from the others. Quizizz had an interactive display, which made it simple for students to use the platform. However, in addition to the positive perception of Quizizz as an assessment platform in English teaching, some students expressed a negative perception of Quizizz as an assessment. According to the data, one of the platform's negative perceptions was the presence of music</p><p class="abstrak"><em>Hampir setiap aspek kehidupan manusia di muka bumi ini terganggu sejak munculnya Covid-19, khususnya pendidikan. Banyak negara telah memutuskan untuk menutup sekolah dan universitas. Kondisi ini memaksa pemerintah Indonesia melalui Kementerian Pendidikan untuk menerapkan kebijakan pemindahan ruang kelas konvensional menjadi ruang kelas daring. Proses ini dilakukan untuk menjaga kesehatan siswa agar terhindar dari Covid-19. Proses pembelajaran dapat dibantu dengan menggunakan salah satu aplikasi di internet yang bernama Student Response System (SRS). Menurut pernyataan tersebut, peneliti menyelidiki persepsi siswa sekolah menengah terhadap penerapan Quizizz sebagai platform penilaian dalam pengajaran bahasa Inggris. Penelitian metode campuran telah diterapkan dalam penelitian ini. Penelitian ini melibatkan 61 siswa sebagai partisipan pada tahap kuantitatif dan 6 siswa pada tahap kualitatif. Instrumen utama yang digunakan dalam penelitian ini adalah kuesioner online dan wawancara mendalam. Temuan menunjukkan bahwa siswa memiliki persepsi positif dan negatif terhadap penggunaan penilaian online, terutama di Quizizz. Para siswa menikmati Quizizz dan menganggapnya menyenangkan, menarik, memotivasi, dan menyenangkan karena platform Quizizz berbeda dari yang lain. Quizizz memiliki tampilan interaktif, yang memudahkan siswa dalam menggunakan platform. Namun, selain persepsi positif tentang Quizizz sebagai platform penilaian dalam pengajaran bahasa Inggris, beberapa siswa menyatakan persepsi negatif tentang Quizizz sebagai penilaian. Menurut data, salah satu persepsi negatif platform adalah kehadiran musik.</em></p>


Think ◽  
2021 ◽  
Vol 21 (60) ◽  
pp. 33-49
Author(s):  
William Lyons

The author sets out to respond to the student complaint that ‘Philosophy did not answer “the big questions”’, in particular the question ‘What is the meaning of life?’ The response first outlines and evaluates the most common religious answer, that human life is given a meaning by God who created us and informs us that this life is just the pilgrim way to the next eternal life in heaven. He then discusses the response that, from the point of view of post-Darwinian science and the evolution of the universe and all that is in it, human life on Earth must be afforded no more meaning than the meaning we would give to a microscopic planaria or to some creature on another planet in a distant universe. All things including human creatures on Planet Earth just exist for a time and that is that. There is no plan or purpose. In the last sections the author outlines the view that it is we humans ourselves who give meaning to our lives by our choices of values or things that are worth pursuing and through our resulting sense of achievement or the opposite. Nevertheless the question ‘What is the meaning of life?’ can mean quite different things in different contexts, and so merit different if related answers. From one point of view one answer may lie in terms of the love of one human for another.


2021 ◽  
Vol 7 (2) ◽  
pp. 227-244
Author(s):  
Kulamangalam Thiagarajan Tamilmani ◽  
Rathinasamy Nagalakshmi

Postmodern literary texts have been exploring characters that are whimsically strange. The tacit plots in the postmodern textual space enable the writers to construct and manifest the mental space of the characters in the textual world. The Rise of Life on Earth written by Joyce Carol Oates concocts the emotional estrangement of the protagonist, Kathleen Hennessy. Decrypting the text amplifies the unabating efforts of Kathleen to survive in a world that has been portrayed as a larger, repressive and pernicious family. Her masquerade to be a shy, passive and well-behaved girl hides the menacing vengeance that has culminated as a result of abuses and afflictions. Her mental spaces are constructed during the course of narration. This paper purports to scrutinize the fragmented psyche of Kathleen and the conceptual integration of mental space and textual space that replicates both social and individualistic reality and expands the understanding of Oates’ text.


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