Nata Atmaja A.,Indonesian Institute of Sciences
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2017
We develop a new method for obtaining the BPS equations of static vortices motivated by the results of the On-Shell method on the standard Maxwell–Higgs model and its Born–Infeld–Higgs model . Our method relies on the existence of what we shall call a BPS energy function Q as such the total energy of BPS vortices EBPS are simply given by an integral of total differential of the BPS energy function, EBPS=∫dQ. Imposing a condition that the effective fields are independent of each other, we may define a BPS Lagrangian LBPS by EBPS≡−∫d2x LBPS. Equating this BPS Lagrangian with the corresponding effective Lagrangian, the equation is expected to be a sum of positive-semidefinite functions Leff−LBPS=∑i NAi 2=0, where N is the number of effective fields. Solving this equation by parts would yields the desired BPS equations. With our method, the various known BPS equations of vortices are derived in a relatively simple procedure. We show that in all models considered here, the BPS energy function is given by a general formula Q=2πaF(f), where a and f are the effective fields for the gauge field and scalar field, and F′(f)=±2f w(f), with w is an overall coupling of the scalar field's kinetic term. © 2017 The Author(s)
News Article | April 19, 2017
Methane-making microbes may have battled “rust-breathing” microbes for dominance in early Earth’s oceans—and kept those oceans from freezing under an ancient, dimmer sun in the process, new research suggests. For much of its first two billion years, Earth was a very different place: oxygen was scarce, microbial life ruled, and the sun was significantly dimmer than it is today. Yet the rock record shows that vast seas covered much of the early Earth under the faint young sun. Scientists have long debated what kept those seas from freezing. A popular theory is that potent gases such as methane—with many times more warming power than carbon dioxide—created a thicker greenhouse atmosphere than required to keep water liquid today. In the absence of oxygen, iron built up in ancient oceans. Under the right chemical and biological processes, this iron rusted out of seawater and cycled many times through a complex loop, or “ferrous wheel.” Some microbes could “breathe” this rust in order to outcompete others, such as those that made methane. When rust was plentiful, an “iron curtain” may have suppressed methane emissions. “The ancestors of modern methane-making and rust-breathing microbes may have long battled for dominance in habitats largely governed by iron chemistry,” says Marcus Bray, a biology doctoral candidate in the laboratory of Jennifer Glass, assistant professor in the Georgia Institute of Technology’s School of Earth and Atmospheric Sciences. Using mud pulled from the bottom of a tropical lake, the researchers gained a new grasp of how ancient microbes made methane despite this “iron curtain.” Collaborator Sean Crowe, an assistant professor at the University of British Columbia, collected mud from the depths of Indonesia’s Lake Matano, an anoxic iron-rich ecosystem that uniquely mimics early oceans. Bray placed the mud into tiny incubators simulating early Earth conditions, and tracked microbial diversity and methane emissions over a period of 500 days. Minimal methane was formed when rust was added; without rust, microbes kept making methane through multiple dilutions. Extrapolating these findings to the past, the team concluded that methane production could have persisted in rust-free patches of ancient seas. Unlike the situation in today’s well-aerated oceans, where most natural gas produced on the seafloor is consumed before it can reach the surface, most of this ancient methane would have escaped to the atmosphere to trap heat from the early sun. Glass was principal investigator of the study in Geobiology. Additional members of the research team are from Georgia Tech, the University of British Columbia, the Indonesian Institute of Sciences, the Skidaway Institute of Oceanography, and the University of Kansas. A grant from NASA Exobiology funded the work. The Center for Dark Energy Biosphere Investigations and the NASA Astrobiology Institute also provided support. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the sponsoring organizations.
News Article | April 17, 2017
IMAGE: Tiny incubators were used to simulate early Earth conditions, tracking microbial diversity and methane emissions over a period of 500 days. view more For much of its first two billion years, Earth was a very different place: oxygen was scarce, microbial life ruled, and the sun was significantly dimmer than it is today. Yet the rock record shows that vast seas covered much of the early Earth under the faint young sun. Scientists have long debated what kept those seas from freezing. A popular theory is that potent gases such as methane -- with many times more warming power than carbon dioxide -- created a thicker greenhouse atmosphere than required to keep water liquid today. In the absence of oxygen, iron built up in ancient oceans. Under the right chemical and biological processes, this iron rusted out of seawater and cycled many times through a complex loop, or "ferrous wheel." Some microbes could "breathe" this rust in order to outcompete others, such as those that made methane. When rust was plentiful, an "iron curtain" may have suppressed methane emissions. "The ancestors of modern methane-making and rust-breathing microbes may have long battled for dominance in habitats largely governed by iron chemistry," said Marcus Bray, a biology Ph.D. candidate in the laboratory of Jennifer Glass, assistant professor in the Georgia Institute of Technology's School of Earth and Atmospheric Sciences and principal investigator of the study funded by NASA's Exobiology and Evolutionary Biology Program. The research was reported in the journal Geobiology on April 17, 2017. Using mud pulled from the bottom of a tropical lake, researchers at Georgia Tech gained a new grasp of how ancient microbes made methane despite this "iron curtain." Collaborator Sean Crowe, an assistant professor at the University of British Columbia, collected mud from the depths of Indonesia's Lake Matano, an anoxic iron-rich ecosystem that uniquely mimics early oceans. Bray placed the mud into tiny incubators simulating early Earth conditions, and tracked microbial diversity and methane emissions over a period of 500 days. Minimal methane was formed when rust was added; without rust, microbes kept making methane through multiple dilutions. Extrapolating these findings to the past, the team concluded that methane production could have persisted in rust-free patches of ancient seas. Unlike the situation in today's well-aerated oceans, where most natural gas produced on the seafloor is consumed before it can reach the surface, most of this ancient methane would have escaped to the atmosphere to trap heat from the early sun. In addition to those already mentioned, the research team included Georgia Tech professors Frank Stewart and Tom DiChristina, Georgia Tech postdoctoral scholars Jieying Wu and Cecilia Kretz, Georgia Tech Ph.D. candidate Keaton Belli, Georgia Tech M.S. student Ben Reed, University of British Columbia postdoctoral scholar Rachel Simister, Indonesian Institute of Sciences researcher Cynthia Henny, Skidaway Institute of Oceanography professor Jay Brandes, and University of Kansas professor David Fowle. This research was funded by NASA Exobiology grant NNX14AJ87G. Support was also provided by a Center for Dark Energy Biosphere Investigations (NSF-CDEBI OCE-0939564) small research grant, and by the NASA Astrobiology Institute (NNA15BB03A). Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the sponsoring organizations. CITATION: Bray M.S., J. Wu, B.C. Reed, C.B. Kretz, K.M. Belli, R.L. Simister, C. Henny, F.J. Stewart, T.J. DiChristina, J.A. Brandes, D.A. Fowle, S.A. Crowe, J.B. Glass. 2017. Shifting microbial communities sustain multi-year iron reduction and methanogenesis in ferruginous sediment incubations. (Geobiology 2017). http://dx. .
News Article | December 1, 2016
MOUNT WAVERLEY, AUSTRALIA, December 01, 2016-- Thomas Spurling, Professor of the Swinburne Business School at the Swinburne University of Technology, has been recognized by Worldwide Branding for showing dedication, leadership and excellence in his profession.With four decades of educational experience, Dr. Spurling demonstrates expertise in physical chemistry, industrial technology and molecular science. He has been at Swinburne for 11 years, now serving as a research professor. He recently had left the Faculty of Life and Social Sciences department to move to the business school. He was then dean of the Faculty of Engineering and Industrial Sciences from 2004-2005. In the future, Dr. Spurling plans to continue his areas of research and career around innovation enterprise. He says persistence has been the key to his sustained success.A former lecturer with the University of Tasmania, Dr. Spurling earned a Postdoctoral Fellow from the University of Maryland in 1967, which followed a Bachelor of Science, with first class honors, in 1962, and a Doctor of Philosophy in 1966, both in physical chemistry, from University of Western Australia.He has also worked outside the educational field. Dr. Spurling serves as a chairman of Advanced Molecular Technologies Pty., Ltd., and as a board member of the International Centre for Radio Astronomy Research (ICRAR). He is also a former scientist and research leader with CSIRO. He was the chief of CSIRO Chemicals and Polymers and then CSIRO Molecular Science from 1989 to 1998. He led the World Bank funded CSIRO-Indonesian Institute of Sciences Management Systems Strengthening Project in Jakarta from 1999 to 2001. He was the chief executive officer of the Cooperative Research Centre (CRC) Wood Innovations from 2005 to 2008.Dr. Spurling was appointed as a member of the Order of Australia in June 2008 for services to chemical science through contributions to national innovation policies, strategies and research, and to the development of professional scientific relationships within the Asian region.He is a Fellow with the Australian Academy of Technological Sciences and Engineering, the Federation of Asian Chemical Societies, and the Royal Australian Chemical Institute. He maintains affiliations with the Design Research Institute of RMIT University and the Australian Institute for Teaching and School Leadership (AITSL).In the past, Dr. Spurling was president of several groups: the Federation of Asian Chemical Societies (FACS), the Royal Australian Chemical Institute (RACI) and the Federation of Australian Scientific and Technological Societies (FASTS). He was also a member of the Prime Minister's Science, Engineering and Innovation Council from 2005 to 2007.Throughout his career, Dr. Spurling has received numerous awards, including the FACS Award for Distinguished Contribution to Economic Development (2003), the Centenary Medal from the Australian Government (2003), the CSIRO Award for Business Excellence (2000), and the Leighton Memorial Medal (1994) and the Rennie Memorial Medal (1971), both from the Royal Australian Chemical Institute.In recognition of all of his achievements, Dr. Spurling was recently inducted into Worldwide Branding.About Worldwide BrandingFor more than 15 years, Worldwide Branding has been the leading, one-stop-shop, personal branding company, in the United States and abroad. From writing professional biographies and press releases, to creating and driving Internet traffic to personal websites, our team of branding experts tailor each product specifically for our clients' needs. From health care to finance to education and law, our constituents represent every major industry and occupation, at all career levels.For more information, please visit http://www.worldwidebranding.com
Ramadhan H.S.,Indonesian Institute of Sciences |
Ramadhan H.S.,University of Indonesia
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2012
In this Letter we show numerical existence of O(4) Dirac-Born-Infeld (DBI) Textures living in (N+1) dimensional spacetime. These defects are characterized by S N→S 3 mapping, generalizing the well-known Hopf fibration into π N(S 3), for all N>3. The nonlinear nature of DBI kinetic term provides stability against size perturbation and thus renders the defects having natural scale. © 2012 Elsevier B.V.
Nugraha A.S.,Indonesian Institute of Sciences
Energy Procedia | Year: 2015
This paper presents a numerical method for solve transient analysis in vibration analysis. The dynamic model of the combat vehicle is used in this paper, A half car lumped mass dynamic model s derived. Numerical simulation is conducted using Runge Kutta fourth order method. The first thing to do is sketch the model of the object to be studied, the next is motion equation derivation, the next thing is to reduce the equations of motion that has been made to be solved by numerical methods with Runge Kutta fourth order. The stepping time in the Runge Kutta fourth order method is important role in numerical analysis, in this study using a timing which is a derivative of the maximum frequency when the vehicle is not damped. The simulation results showed that for stepping over a specified time of 0.01 s produce unstable simulation results, in contrast, using a time step of 0.001 s has provide a more stable results. © 2015 The Authors. Published by Elsevier Ltd.
Kobe University, Toray Industries Inc, Tokyo Metropolitan Institute of Medical Science, University of Indonesia and Indonesian Institute of Sciences | Date: 2013-09-27
A HCV particle formation promoter is capable of promoting formation of HCV particles in culture cells, and a method enhances production of HCV particles. A method evaluates an anti-HCV agent candidate substance, and a method produces a HCV vaccine. The HCV particle formation promoter includes as an active ingredient a statin or a pharmaceutically acceptable salt thereof. Addition of the statin or pharmaceutically acceptable salt thereof to HCV-infected culture cells can promote formation of infectious HCV particles and enhance production of the particles. In addition, an anti-HCV agent candidate substance is evaluated by culturing HCV-infected cells in the presence of the HCV particle formation promoter and the anti-HCV agent candidate substance. Further, a HCV vaccine is produced by using HCV particles produced by the method of enhancing production of HCV particles.
Kobe University, Toray Industries Inc, Tokyo Metropolitan Institute of Medical Science, University of Indonesia and Indonesian Institute of Sciences | Date: 2015-08-05
Provided are a HCV particle formation promoter capable of promoting formation of HCV particles in culture cells, and a method of enhancing production of HCV particles. Also provided are a method of evaluating an anti-HCV agent candidate substance, and a method of producing a HCV vaccine. The HCV particle formation promoter comprises as an active ingredient a statin or a pharmaceutically acceptable salt thereof. Addition of the statin or pharmaceutically acceptable salt thereof to HCV-infected culture cells can promote formation of infectious HCV particles and enhance production of the particles. In addition, an anti-HCV agent candidate substance is evaluated by culturing HCV-infected cells in the presence of the HCV particle formation promoter and the anti-HCV agent candidate substance. Further, a HCV vaccine is produced by using HCV particles produced by the method of enhancing production of HCV particles.
News Article | February 17, 2017
JAKARTA (Reuters) - The race to become governor of Indonesia's capital was heading for a second round between the incumbent Christian and a Muslim former education minister after neither appeared to win a majority in a Wednesday election. The Jakarta poll has been overshadowed by religious tensions, with Islamist-led protests against Governor Basuki Tjahaja Purnama, an ethnic Chinese Christian, and calls for voters to choose a Muslim leader for the city. Analysts say divisions could linger and even deepen as the vote, which is also being widely seen as a proxy battle for the next presidential election, in 2019, appeared to be heading for a second round, according to unofficial sample vote counts. His main rival, former education minister Anies Baswedan, is backed by a retired general, Prabowo Subianto, who is promising a comeback to the national stage after losing to Widodo in the 2014 presidential vote. "There would be tension that will be stored until 2019, because of course all this is not really against Purnama, it's against Widodo. Prabowo is coming in now," said Wimar Witoelar, a Jakarta-based political analyst. Purnama had secured 43.08 percent of the votes, just ahead of Baswedan on 40.14 percent, based on a quick sample count of about 95 percent of the vote by private polling firm SMRC. The other candidate, Agus Yudhoyono, the son of former President Susilo Bambang Yudhoyono, was in third place with 16.78 percent. Other pollsters showed similar results. A candidate needs to get more than 50 percent of the votes in the first round to win outright. The earliest a second round will be held is April. The General Elections Commission is expected to announce official results in around two weeks. Indonesia has the world's largest Muslim population but is officially secular and home to minority Christian, Hindu, Buddhist and other communities. Overshadowing the campaign has been Purnama's trial for allegedly insulting the Koran in connection with remarks he made about how people vote. The trial, which began in December, seemed to dent his support initially but more recently he has rebounded in opinion polls, helped by middle class approval of his efforts to improve the bureaucracy and tackle traffic jams and flooding. Baswedan, who was dropped from Widodo's cabinet after a reshuffle in mid-2016, has largely stayed out of the headlines as the other two candidates - Purnama and Yudhoyono - fought a bitter campaign. But Baswedan's strategy of targeting the Islamic vote, at a time when conservative Muslim groups were urging voters to shun a non-Muslim leader, gave him a late boost, analysts say. "The votes may have shifted from Yudhoyono to Baswedan," said Irine Gayatri, a political analyst at the Indonesian Institute of Sciences. Ethnicity and religion would likely again be major issues in a second round, Gayatri said. The president said he hoped for an easing of tension. "We hope that everybody can return as a family after these elections," Widodo said after casting his vote. Purnama, dressed in his signature checkered shirt, met cheering supporters at his campaign headquarters. "The struggle is not over," he told them. "Everyone wants just one round but we're grateful to have come at least this far." Baswedan said his campaign for a second round would focus on policies. "We will focus on programs, about jobs, about quality education, needs that are important and urgent for families and people in Jakarta," he told reporters. The votes in Jakarta and scores of other regions in the world's third-largest democracy were peaceful and mostly running without hitches, police said.
News Article | February 15, 2017
For the 100 million people who live within 3 feet of sea level in East and Southeast Asia, the news that sea level in their region fluctuated wildly more than 6,000 years ago is important, according to research published by a team of ocean scientists and statisticians, including Rutgers professors Benjamin Horton and Robert Kopp and Rutgers Ph.D. student Erica Ashe. That's because those fluctuations occurred without the assistance of human-influenced climate change. In a paper published in Nature Communications, Horton, Kopp, Ashe, lead author Aron Meltzner and others report that the relative sea level around Belitung Island in Indonesia rose twice just under 2 feet in the period from 6,850 years ago to 6,500 years ago. That this oscillation took place without any human-assisted climate change suggests to Kopp, Horton and their co-authors that such a change in sea level could happen again now, on top of the rise in sea level that is already projected to result from climate change. This could be catastrophic for people living so close to the sea. "This research is a very important piece of work that illustrates the potential rates of sea-level rise that can happen from natural variability alone," says Horton, professor of marine and coastal sciences in the School of Environmental and Biological Sciences. "If a similar oscillation were to occur in East and Southeast Asia in the next two centuries, it could impact tens of millions of people and associated ecosystems." Meltzner, a senior research fellow at the Earth Observatory of Singapore at Nanyang Technological University, along with Horton, Kopp and their co-authors, used coral microatolls to understand when, and by how much, the sea level had risen and fallen near the Indonesian island of Belitung, which lies between Sumatra and Borneo. A microatoll is a circular coral colony, typically no more than about 20 feet across, in which the topmost coral is dead and the bottom part living and growing. By taking samples from microatolls in different places, scientists can date rises and falls of sea level. The microatolls are what scientists call a "proxy" - a natural process that provides a reliable record of past events. "In any region, you try to find the proxy controlled by sea level," Horton says. "In New Jersey, we have no corals, so we use salt marshes. In the tropics, corals are the go-to proxy." The scientists studied microatolls at two sites on opposite sides of the island. Meltzner says they didn't expect the fluctuations they found because those changes in sea level contradicted what they knew about sea level in Southeast Asia. "Our conventional understanding of ocean circulation and ice-melting history told us that such fluctuations should not occur, so we were a bit mystified at the results from our first site," Meltzner says. "But after finding a similar pattern at a second site 80 kilometers to the southeast, and ruling out other plausible explanations, it was clear that the coral growth patterns must reflect regional changes in sea level. There would be way too many coincidences otherwise." The paper comes out of a long-running research project aimed at understanding the physical processes involved in sea-level rise. Such understanding, Kopp says, is necessary to help scientists understand the present and likely future state of the ocean. "This is a basic science problem," Kopp says. "It's about understanding past changes. Understanding what drove those changes is what allows us to test the climate models we use to predict future changes." In addition to Meltzner, Horton, Kopp, and Ashe, the authors are Adam Switzer, Qiang Qiu, Emma Hill, and Jedrzej Majewski, also of Nanyang Technological University in Singapore; David Hill of Oregon State University, Sarah Bradley of Utrecht University and Delft University of Technology in the Netherlands; and Danny Natawidjaja and Bambang Suwargadi of the Indonesian Institute of Sciences.