Tata Institute of Fundamental Research

www.tifr.res.in www.tifrh.res.in/index.html/
Mumbai, India

The Tata Institute of Fundamental Research is a research institution in Mumbai, India, dedicated to basic research in mathematics and the science. It is a Deemed University and works under the umbrella of the Department of Atomic Energy of the Government of India. It is located at Navy Nagar, Colaba, Mumbai. TIFR conducts research primarily in natural science, mathematics, biological science and theoretical computer science and is considered one of the outstanding research centres in India. TIFR has a graduate program leading to a PhD in all the major fields of study.The TIFR is rated with “A” grade as per MHRD. It is the only one among 4 in Maharashtra State, the other 3 being centrally funded UDCT , TISS and CIFE. Wikipedia.

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News Article | May 19, 2017
Site: cerncourier.com

On 4 April, CERN alumnus Tim Berners-Lee received the 2016 A M Turing Award for his invention of the World Wide Web, the first web browser, and the fundamental protocols and algorithms allowing the web to scale. Named in honour of British mathematician and computer scientist Alan Turing, and often referred to as the Nobel prize of computing, the annual award of $1 million is given by the Association for Computing Machinery. In 1989, while working at CERN, Berners-Lee wrote a proposal for a new information-management system for the laboratory, and by the end of the following year he had invented one of the most influential computing innovations in history – the World Wide Web. Berners-Lee is now a professor at Massachusetts Institute of Technology and the University of Oxford, and director of the World Wide Web Consortium and the World Wide Web Foundation. The International Centre for Theoretical Physics 2016 Dirac Medal has been awarded to Nathan Seiberg of the Institute for Advanced Study in Princeton, and Mikhail Shifman and Arkady Vainshtein of the University of Minnesota. The award recognises the trio’s important contributions to field theories in the non-perturbative regime and in particular for exact results obtained in supersymmetric field theories. The second edition of the Guido Altarelli Award, given to young scientists in the field of deep inelastic scattering and related subjects, was awarded to two researchers during the 2017 Deep Inelastic Scattering workshop held in Birmingham, UK, on 3 April. Maria Ubiali of Cambridge University in the UK was recognised for her theoretical contributions in the field of proton parton density functions, and in particular for her seminal contributions to the understanding of heavy-quark dynamics. Experimentalist Paolo Gunnellini of DESY, who is a member of the CMS collaboration, received the award for his innovative ideas in the study of double parton scattering and in Monte Carlo tuning. Four members of the IceCube neutrino observatory, based at the South Pole, have independently won awards recognising their contributions to the field. Aya Ishihara of Chiba University in Japan was awarded the 37th annual Saruhashi Prize, given each year to a female scientist under the age of 50 for exceptional research accomplishments. This year’s prize, presented in Tokyo on 27 May, cites Ishihara’s contributions to high-energy astronomy with the IceCube detector. Fellow IceCube collaborator Subir Sarkar of the University of Oxford, UK, and the Niels Bohr Institute in Denmark has won the 4th Homi Bhabha prize. Awarded since 2010 by the Tata Institute of Fundamental Research (TIFR) in India and the International Union of Pure and Applied Physics, the prize recognises an active scientist who has made distinguished contributions in the field of high-energy cosmic-ray and astroparticle physics over an extended academic career. Sarkar has also worked on the Pierre Auger Observatory and is a member of the Cherenkov Telescope Array collaboration. Meanwhile, former IceCube spokesperson Christian Spiering from DESY has won the O’Ceallaigh Medal for astroparticle physics, awarded every second year by the Dublin Institute for Advanced Studies. Spiering, who led the collaboration from 2005 to 2007 and also played a key role in the Lake Baikal Neutrino Telescope, was honoured “for his outstanding contributions to cosmic-ray physics and to the newly emerging field of neutrino astronomy in particular”. Both he and Sarkar will receive their awards at the 35th International Cosmic Ray Conference in Busan, South Korea, on 13 July. Finally, IceCube member Ben Jones of the University of Texas at Arlington has won the APS 2017 Mitsuyoshi Tanaka Dissertation Award in Experimental Particle Physics, for his thesis “Sterile Neutrinos in Cold Climates”. An awards ceremony took place at CERN on 3 April recognising companies that have won contracts to start building the prototype phase of the Helix Nebula Science Cloud (HNSciCloud). Initiated by CERN in 2016, HNSciCloud is a €5.3 million pre-commercial procurement tender driven by 10 leading research organisations and funded by the European Commission. Its aim is to establish a European cloud platform to support high-performance computing and big-data capabilities for scientific research. The April event marked the official beginning of the prototype phase, which covers the procurement of R&D services for the design, prototype development and pilot use of innovative cloud services. The three winning consortia are: T-Systems, Huawei, Cyfronet and Divia; IBM; and RHEA Group, T-Systems, Exoscale and SixSq. Each presented its plans to build the HNSciCloud prototype and the first deliverables are expected by the end of the year, after which two consortia will proceed to the pilot phase in 2018. The CERN Accelerator School (CAS) organised a specialised course devoted to beam injection, extraction and transfer in Erice, Sicily, from 10 to 19 March. The course was held in the Ettore Majorana Foundation and Centre, and was attended by 72 participants from 25 countries including China, Iran, Russia and the US. The intensive programme comprised 32 lectures and two seminars, with 10 hours of case studies allowing students to apply their knowledge to real problems. Following introductory talks on electromagnetism, relativity and the basics of beam dynamics, different injection and extraction schemes were presented. Detailed lectures about the special magnetic and electrostatic elements for the case of lepton and hadron beams followed. State-of-the-art kicker and septa designs were discussed, as were issues related to stripping-injection and resonant extraction as used in medical settings. An overview of optics measurements in storage rings and non-periodic structures completed the programme, with talks about the production of secondary and radioactive beams and exotic injection methods. The next CAS course, focusing on advanced accelerator physics, will take place at Royal Holloway University in the UK from 3–15 September. Later in the year, CAS is participating in a joint venture in collaboration with the accelerator schools of the US, Japan and Russia. This school is devoted to RF technologies and will be held in Japan from 16–26 October. Looking further ahead, schools are currently planned in 2018 on accelerator physics at the introductory level, on future colliders and on beam instrumentation and diagnostics. See https://www.cern.ch/schools/CAS. Around 100 participants from 15 countries attended the 2017 Testing Gravity Conference at the Simon Fraser University, Harbour Centre, in Vancouver, Canada, on 25 to 28 January. The conference, the second such meeting following the success of the 2015 event, brought together experts exploring new ways to test general relativity (GR). GR, and its Newtonian limit, work very well in most circumstances. But gaps in our understanding appear when the theory is applied to extremely small distances, where quantum mechanics reigns, or extremely large distances, when we try to describe the universe. Advancing technologies across all areas of physics open up opportunities for testing gravity in new ways, thus helping to fill these gaps. The conference brought together renowned cosmologists, astrophysicists, and atomic, nuclear and particle physicists to share their specific approaches to test GR and to explore ways to address long-standing mysteries, such as the unexplained nature of dark matter and dark energy. Among the actively discussed topics were the breakthrough discovery in February 2016 of gravitational waves by the LIGO observatory, which has opened up exciting opportunities for testing GR in detail (CERN Courier January/February 2017 p34), and the growing interest in gravity tests among the CERN physics community – specifically regarding attempting to measure the gravitational force on antihydrogen with three experiments at CERN’s Antiproton Decelerator (CERN Courier January/February 2017 p39). Among other highlights there were fascinating talks from pioneers in their fields, including cosmologist Misao Sasaki, one of the fathers of inflationary theory; Eric Adelberger, a leader in gravity tests at short distances; and Frans Pretorius, who created the first successful computer simulations of black-hole collisions. This is an exciting time for the field of gravity research. The LIGO–Virgo collaboration is expected to detect many more gravitational-wave events from binary black holes and neutron stars. Meanwhile, a new generation of cosmological probes currently under development, such as Euclid, LSST and SKA, are stimulating theoretical research in their respective domains (CERN Courier May 2017 p19). We are already looking forward to the next Testing Gravity in Vancouver in 2019. On 12 April, CERN hosted the seven-member high-level group of scientific advisers to the European Commission, which provides independent scientific advice on specific policy issues. Led by former CERN Director-General Rolf Heuer, the group toured ATLAS and the AMS Payload Operations Control Centre. On 18 April, Czech minister of health Miloslav Ludvik visited CERN, during which he toured the ALICE experiment and signed the guestbook with head of Member State relations Pippa Wells. Minister for higher education and science in Denmark Søren Pind visited CERN on 25 April, touring the synchrocyclotron, the Antiproton Decelerator, ALICE and ATLAS. Here he is pictured (centre) meeting ATLAS spokesperson Karl Jakobs. Dr Viktoras Pranckietis MP and speaker of the Seimas, Republic of Lithuania, visited CERN on 26 April, taking in CMS, ISOLDE and MEDICIS. He signed the guestbook with senior adviser for Lithuania Tadeusz Kurtyka (left) and director for finance and human resources Martin Steinacher.

Vaze R.,Tata Institute of Fundamental Research
IEEE Transactions on Wireless Communications | Year: 2011

Delay-reliability (D-R), and throughput-delay-reliability (T-D-R) tradeoffs in an ad hoc network are derived for single hop and multi-hop transmission with automatic repeat request (ARQ) on each hop. The delay constraint is modeled by assuming that each packet is allowed at most D retransmissions end-to-end, and the reliability is defined as the probability that the packet is successfully decoded in at most D retransmissions. The throughput of the ad hoc network is characterized by the transmission capacity, where the transmission capacity is defined to be the maximum density of spatial transmissions that can be simultaneously supported in an ad hoc network under quality of service (QoS) constraints (maximum retransmissions and reliability). The transmission capacity captures the T-D-R tradeoff as it incorporates the dependence between the throughput, the maximum delay, and the reliability. Given an end-to-end retransmission constraint of D, the optimal allocation of the number of retransmissions allowed at each hop is derived that maximizes a lower bound on the transmission capacity. Optimizing over the number of hops, single hop transmission is shown to be optimal for maximizing a lower bound on the transmission capacity in the sparse network regime. © 2011 IEEE.

Jaiswal A.,Tata Institute of Fundamental Research
Physical Review C - Nuclear Physics | Year: 2013

Starting from the Boltzmann equation with the relaxation time approximation for the collision term and using a Chapman-Enskog-like expansion for the distribution function close to equilibrium, we derive hydrodynamic evolution equations for the dissipative quantities directly from their definition. Although the form of the equations is identical to those obtained in traditional Israel-Stewart approaches employing Grad's 14-moment approximation and the second moment of the Boltzmann equation, the coefficients obtained are different. In the case of a one-dimensional scaling expansion, we demonstrate that our results are in better agreement with a numerical solution of the Boltzmann equation as compared to Israel-Stewart results. We also show that including approximate higher-order corrections in viscous evolution significantly improves this agreement, thus justifying the relaxation time approximation for the collision term. © 2013 American Physical Society.

Jaiswal A.,Tata Institute of Fundamental Research
Physical Review C - Nuclear Physics | Year: 2013

We present the derivation of a novel third-order hydrodynamic evolution equation for the shear stress tensor from kinetic theory. The Boltzmann equation with a relaxation time approximation for the collision term is solved iteratively using a Chapman-Enskog-like expansion to obtain the nonequilibrium phase-space distribution function. Subsequently, the evolution equation for the shear stress tensor is derived from its kinetic definition up to third order in gradients. We quantify the significance of the new derivation within a one-dimensional scaling expansion and demonstrate that the results obtained using the third-order viscous equations derived here provides a very good approximation to the exact solution of the Boltzmann equation in a relaxation time approximation. We also show that the time evolution of pressure anisotropy obtained using our equations is in better agreement with transport results than that obtained with an existing third-order calculation based on the second law of thermodynamics. © 2013 American Physical Society.

Krishnan Y.,Tata Institute of Fundamental Research | Simmel F.C.,TU Munich
Angewandte Chemie - International Edition | Year: 2011

In biology, nucleic acids are carriers of molecular information: DNA's base sequence stores and imparts genetic instructions, while RNA's sequence plays the role of a messenger and a regulator of gene expression. As biopolymers, nucleic acids also have exciting physicochemical properties, which can be rationally influenced by the base sequence in myriad ways. Consequently, in recent years nucleic acids have also become important building blocks for bottom-up nanotechnology: as molecules for the self-assembly of molecular nanostructures and also as a material for building machinelike nanodevices. In this Review we will cover the most important developments in this growing field of nucleic acid nanodevices. We also provide an overview of the biochemical and biophysical background of this field and the major "historical" influences that shaped its development. Particular emphasis is laid on DNA molecular motors, molecular robotics, molecular information processing, and applications of nucleic acid nanodevices in biology. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Manoharan P.K.,Tata Institute of Fundamental Research
Astrophysical Journal | Year: 2012

This paper presents an analysis of three-dimensional evolution of solar wind density turbulence and speed at various levels of solar activity between solar cycles 22 and 24. The solar wind data used in this study have been obtained from the interplanetary scintillation (IPS) measurements made at the Ooty Radio Telescope, operating at 327MHz. Results show that (1) on average, there was a downward trend in density turbulence from the maximum of cycle 22 to the deep minimum phase of cycle 23; (2) the scattering diameter of the corona around the Sun shrunk steadily toward the Sun, starting from 2003 to the smallest size at the deepest minimum, and it corresponded to a reduction of 50% in the density turbulence between the maximum and minimum phases of cycle 23; (3) the latitudinal distribution of the solar wind speed was significantly different between the minima of cycles 22 and 23. At the minimum phase of solar cycle 22, when the underlying solar magnetic field was simple and nearly dipole in nature, the high-speed streams were observed from the poles to 30° latitudes in both hemispheres. In contrast, in the long-decay phase of cycle 23, the sources of the high-speed wind at both poles, in accordance with the weak polar fields, occupied narrow latitude belts from poles to 60° latitudes. Moreover, in agreement with the large amplitude of the heliospheric current sheet, the low-speed wind prevailed in the low- and mid-latitude regions of the heliosphere. (4) At the transition phase between cycles 23 and 24, the high levels of density and density turbulence were observed close to the heliospheric equator and the low-speed solar wind extended from the equatorial-to-mid- latitude regions. The above results in comparison with Ulysses and other in situ measurements suggest that the source of the solar wind has changed globally, with the important implication that the supply of mass and energy from the Sun to the interplanetary space has been significantly reduced in the prolonged period of low solar activity. The IPS results are consistent with the onset and growth of the current solar cycle 24, starting from the middle of 2009. However, the width of the high-speed wind at the northern high latitudes has almost disappeared and indicates that the ascending phase of the current cycle has almost reached the maximum phase in the northern hemisphere of the Sun. However, in the southern part of the hemisphere, the solar activity has yet to develop and/or increase. © 2012. The American Astronomical Society. All rights reserved..

Choudhury S.,Tata Institute of Fundamental Research
Nuclear Physics B | Year: 2015

In this paper my prime objective is to explain the generation of large tensor-to-scalar ratio from the single field sub-Planckian inflationary paradigm within Randall-Sundrum (RS) single braneworld scenario in a model independent fashion. By explicit computation I have shown that the effective field theory prescription of brane inflation within RS single brane setup is consistent with sub-Planckian excursion of the inflaton field, which will further generate large value of tensor-to-scalar ratio, provided the energy density for inflaton degrees of freedom is high enough compared to the brane tension in high energy regime. Finally, I have mentioned the stringent theoretical constraint on positive brane tension, cut-off of the quantum gravity scale and bulk cosmological constant to get sub-Planckian field excursion along with large tensor-to-scalar ratio as recently observed by BICEP2 or at least generates the tensor-to-scalar ratio consistent with the upper bound of Planck (2013 and 2015) data and Planck+BICEP2+Keck Array joint constraint. © 2015 The Author.

Udgaonkar J.B.,Tata Institute of Fundamental Research
Archives of Biochemistry and Biophysics | Year: 2013

Polypeptide chain collapse is an integral component of a protein folding reaction. In this review, experimental characterization of the interplay of polypeptide chain collapse, secondary structure formation, consolidation of the hydrophobic core and the development of tertiary interactions, is scrutinized. In particular, the polypeptide chain collapse reaction is examined in the context of the three phenomenological models of protein folding - the hydrophobic collapse model, the framework model and the nucleation condensation model - which describe different ways by which polypeptide chains are able to fold in biologically relevant time-scales. © 2012 Elsevier Inc. All rights reserved.

Ravinder S.,Tata Institute of Fundamental Research
Translational psychiatry | Year: 2013

Selective serotonin reuptake inhibitors (SSRIs) are reported to exacerbate symptoms of anxiety when treatment is initiated. These clinical findings have been extended to animal models wherein SSRIs also potentiate anxiety and fear learning, which depend on the amygdala. Yet, little is known about the role of specific amygdalar circuits in these acute effects of SSRIs. Here, we first confirmed that a single injection of fluoxetine 1 h before auditory fear conditioning potentiated fear memory in rats. To probe the neural substrates underlying this enhancement, we analyzed the expression patterns of the immediate early gene, Arc (activity-regulated cytoskeleton-associated protein). Consistent with previous reports, fear conditioning induced Arc protein expression in the lateral and basal amygdala. However, this was not enhanced further by pre-treatment with fluoxetine. Instead, fluoxetine significantly enhanced expression of Arc in the central amygdala (CeA) and the bed nucleus of the stria terminalis (BNST). Next, we tested whether direct targeted infusions of fluoxetine into the CeA, or BNST, leads to the same fear-potentiating effect. Strikingly, direct infusion of fluoxetine into the BNST, but not the CeA, was sufficient to enhance fear memory. Moreover, this behavioral effect was also accompanied by robust Arc expression in the CeA, similar to the systemic injection. Our results identify a novel role for the BNST in the acute fear-enhancing effects of SSRIs. These findings highlight the need to look beyond the traditional focus on input nuclei of the amygdala and add to accumulating evidence implicating these microcircuits in gating fear and anxiety.

The present invention discloses a method for securing information flow in an information system. The method comprises intercepting access requests to information in the information system by all applications running in the information system, intuitively assigning labels to all the information and the applications depending on the application requirements, combining the application making the access request and the information for which the access request is made with their respective labels, checking allowance of the access request based on comparison of the label corresponding to the application making the access request and the label corresponding to the information for which the access request is made and accordingly providing access of the information to the application on detection of allowable access request else denying the access request.

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