870 research outputs found
Replication Data for: Bird’s Decision to Shift the Direction of Migration Path Depends on the Position of Sun as well as Moon: A Directional Statistical Inference
No full textDataset for: Bird’s Decision to Shift the Direction of Migration
Path Depends on the Position of the Sun as well as Moon:
A Directional Statistical Inference
(Author: Prithwish Ghosh, Debashis Chatterjee, Amlan Banerjee
Tea Tales – India’s ever evolving chai culture
No full textAs we observed International Tea Day on May 21, to peek into the vibrant history of chai and chai tapris in India, Village Square spoke to Arup K Chatterjee, professor of English at OP Jindal Global University. He is the author of widely acclaimed books including, The Purveyors of Destiny: A Cultural Biography of the Indian Railways and The Great Indian Railways
6 Indians who helped make London the city it is today
No full textArup K Chatterjee, author of Indians in London, tells us about the Indian people who came to London and changed it — as well as Britain and the world — for good
Strength in Numbers : An Art of Life
No full textArt, often through metaphors, depicts that which is visible, while Science works hard to uncover what is hidden and yet unknown, making the two realms appear seemingly at odds with each other. However, both these endeavors are complementary in their pursuit of interpreting the physical world and communicating that vision to humanity. This image is a representation of my research in theoretical biophysics through my artwork. I work on living or 'Active' systems, like birds, fish and bacteria, which show a wide range of spectacular community phenomena of which no analogue can be found in the inanimate world. In this image we see schools of fish self-organize into travelling density waves (top right), coherently moving clusters (middle) and swirls (bottom), just a few of many such fantastic collective behavior that living systems exhibit. Indeed, there is strength in numbers: by flocking, these living entities ensure that they are protected from predation and environmental shocks. Such self-organization into collective structures is spontaneous, intriguing and often breath-taking, and as such captures the imagination of artists and scientists alike.Open Restriction set for Item 110825 on 2019-05-07T20:26:32Z with date null by [email protected] by Emilie Staubs ([email protected]) on 2019-05-07T20:28:16Z
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Previous issue date: 2019Ope
Cumellana Petrescu, Chatterjee & Schizas, 2012, gen. nov.
No full textCumellana gen. nov. Diagnosis. Female. Carapace without antennal notch. Antenna 1 long, second article of peduncle without tubercle. Labium with a forked terminal seta. Maxilliped 1 with large dactylus. Maxilliped 3 with long propodus, twice as long as carpus. Pereopod 1 dactylus with short terminal setae. Pereopod 2 dactylus with three terminal short setae, middle one highly robust. Male unknown. Etymology. The name is a combination between the generic name Cumella and the Christian name of the daughter of first author, Ana. Type species. Cumellana caribbica sp. nov. Remarks. The new genus could be distinguished from other genera of the family Nannastacidae by having long antennules and pereopod 2 with short terminal setae, equal in length.Published as part of Petrescu, Iorgu, Chatterjee, Tapas & Schizas, Nikolaos V., 2012, New genus and new species of Cumacea (Crustacea: Peracarida) from the mesophotic coral ecosystem of SW Puerto Rico, Caribbean Sea, pp. 55-61 in Zootaxa 3476 on page 58, DOI: 10.5281/zenodo.21129
Non-equilibrium physics of driven living matter
No full textThe student, Purba Chatterjee, submitted this Dissertation for approval on 2021-05-07 at 09:11.In this dissertation, I explore how complex macroscopic collective phases emerge from stochastic interactions of the components of a biological system. In addition, I examine the conditions for non-equilibrium transitions from one stable phase to another. This dissertation is divided into two parts. Part I concerns systems broadly classified as active matter. I focus on three specific examples of emergent collective phases in active systems: flocking, chemotactic aggregation, and emergent elasticity.
1. Flocking:- I study the transition to long-range orientational order in polar active systems with a simple agent-based model for flocking, as well as its derived stochastic hydrodynamics. Through exact Gillespie simulations and analytical calculations, I show that binary interactions are insufficient to generate polar order, in agreement with experimental studies on actomyosin assays. However, noisy three-body interactions are both necessary and sufficient to capture the complete phenomenology of the flocking transition at high densities. I further show that imposition of skewed noise statistics can generate artifactual polar order with just two-body interactions. Moreover, the intrinsic stochasticity of microscopic interactions predicts a new phase at low densities mediated by just two-body interactions. This phase, characterized by transient local order, has been identified experimentally in fish schools.
2. Chemotactic aggregation:- I develop a field-theoretic description for active systems, based on a density functional description of crystalline materials modified to capture orientational ordering. I enumerate the many advantages offered by this framework in studying collective phases in active systems, with particle resolution, but on diffusive timescales. Modifying it to describe run and tumble chemotaxis, I show that this model can capture particle aggregation in an externally imposed constant attractant field, as observed for phototactic or thermotactic agents. I also show that this model captures particle aggregation through self-chemotaxis, an important mechanism that aids quorum dependent cellular interactions.
3. Emergent elasticity:- I demonstrate that agent-based models, with simple rules governing the reaction of individual agents to controlled perturbations, can capture experimentally-observed emergent elastic responses in biological systems. I also motivate a formal elastic theory for active systems based on a density functional description of crystalline materials, and discuss the potential as well as the challenges of this formalism.
Part II concerns transcription, the process by which molecular machines called RNA polymerases (RNAPs), synthesize messenger RNA (mRNA) from the genome. I study the purely mechanical regulation of collective modes of RNAP dynamics through transcription-induced DNA supercoiling. I formulate a continuum deterministic model for the translocation of RNAPs on a typical gene, where the speed of an RNAP is coupled to the local DNA supercoiling as well as the density of RNAPs on the gene. Moreover, I propose that transcription factors can act as physical barriers to the diffusion of DNA supercoils. I show that unlike existing theories, this model successfully recapitulates the recent experimental observation that DNA supercoiling drives a transition from cooperative to antagonistic RNAP dynamics when RNAP loading is interrupted. The novel hypotheses that form the basis of this model have important implications for transcription dynamics in the genomic context, where genes may affect each other's transcription efficiencies from a long distance via supercoil diffusion. As such, this work presents an important stepping stone towards understanding the collective dynamics of the molecular machines involved in gene expression.Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2022-01-12 without embargo termsThe student, Purba Chatterjee, accepted the attached license on 2021-05-07 at 09:05.This Dissertation was approved for publication on 2021-05-13 at 14:35.DSpace SAF Submission Ingestion Package generated from Vireo submission #16640 on 2022-01-12 at 12:42:26Made available in DSpace on 2022-01-12T21:40:28Z (GMT). No. of bitstreams: 3
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Previous issue date: 2021-05-1
Copidognathus gurui Chatterjee & Pešić 2014, sp. nov.
No full text<i>Copidognathus gurui</i> sp. nov. <p>(Figs. 1­ 4)</p> <p> <b>Material examined.</b> Holotype (female), paratype (female), and additional materials ­ two females used for SEM, Matemwe (05 o 52'S, 39 o 21'E) the east coast of Unguja, Zanzibar, Tanzania in coral rubble of <i>Fungia</i> (Anthozoa, Scleractinia), August 17 th 2004, coll. M Raes & H Gheerardyn.</p> <p> <b>Description</b></p> <p> Female. Idiosoma 295­ 317 (holotype: 317) µm long. AD 104­ 111 (holotype: 106) µm long. Anterior half of AD joining with dorsal part of AE. AD with frontal process and three areolae. Anterior areola oblong; paired crescent shaped middle areolae with 18­ 20 rosette pores each. Paired ds 1 anterior to middle areolae on AD. Pair of gland pores lie near anterolateral margin of AD anterior to ds 1. Area between areolae comperises large sized panels (panels not subdivided). Posterior margin of AD with a ridge containing a row of panels, each panel subdivided comprising four to eight small shallow subpanels. OC 82­ 84 µm long, 51­ 56 µm width, length to width ratio about 1.6, each with two corneae, areolae with rosette pores medial to corneae and posterolateral to posterior cornea; gland pore lateral to posterior cornea adjacent to lateral margin of OC; pore canaliculus present adjacent to lateral margin of OC. Setae ds 2 located at anteromedial corner of OC. PD 173 – 193 (holotype: 193) µm long. PD with two middle and two lateral costae. Each middle costae about 16 µm wide: with one to two rosette pores (each rosette pore with prominent ostium and canaliculi in and around it) and with panels lateral to it (each panel subdivided comprising subpanels) (Figs. 1D, 3E, F). Anterior part of middle costae and lateral costae joined together with panels (each panel with subpanels). Area between two middle costae three to six panels wide, panels not subdivided (devoid of subpanels). Setae ds 3 – ds 5 on PD. Gland pores lateral to middle costae on posterior part of PD. AE with three pairs of ventral setae and a pair of epimeral pores. Paired ventrolateral areolae between insertion of legs I and II, paired marginal areolae posterior to insertion of leg II. PE with three ventral and one dorsal seta. GA 150­ 153 (holotype: 151) µm long, GO 50­ 59 (holotype: 52) µm long. Distance between anterior end of GO and that of GA subequal to GO length. Paragenital areolae well developed. Three pairs of PGS present. In holotype anterior PGS 22 µm anterior to anterior end of GO; middle pair of PGS posterior to anterior margin of GO, 32 µm apart from lateral margin of GA; third pair near posterior side of GO. Pair of SGS located at the anterior end of genital sclerites.</p> <p> Gnathosoma 83 ­ 93 µm long. Palp consisting of four segments. Tip of rostrum just passing distal end of P 3. P 1 and P 3 devoid of any seta. P 2 with one dorsal seta distally. P 4 with three long proximal seta and one minute distal seta. Proto and deutorostral seta situated at the tip of rostrum; tritorostral setae (long maxillary setae of rostrum) located at 0.35 of rostrum length from its tip. Gnathosomal base with a pair of setae (basirostral setae). Rostral sulcus long extends posteriorly just beyond the tritorostral seta.</p> <p>Chaetotaxy of legs: trochanters I­IV, 1­ 1­ 1­ 0; basifemora I­IV, 2­ 2­ 2­ 2; telofemora I­IV, 5­ 5­ 3­ 3; genua I­IV, 4­ 4­ 3­ 3; tibiae I­IV, 7­ 7­ 5­ 5; tarsi I­IV (PAS excluded), 7­ 4­ 4­ 3. Telofemora III­IV with two dorsal setae and one ventral seta. Telofemur I swollen with well developed trilobed ventrolateral lamella. Tibia I with three ventral setae (one long, pointed ventral seta and two thick, smaller ventromedial setae). Tibia II with one long, pointed ventral seta and two thick, pectinate ventromedial setae. Tibia III with one thick, pectinate ventromedial seta. All setae of tibia IV smooth. Tibia I with two denticulate proximoventral processes (lamella) (Fig. 1E). Tibia II with a feebly developed (not clear properly) proximoventral process. Tarsus I with three dorsal setae, one solenidion, three ventral setae and two eupathidial doublet PAS. Tarsus II with three dorsal setae, one solenidion; PAS obscured by specimen compression. Tarsus III with four dorsal setae (distance between two basidorsal setae a little less than height of the segment) and two PAS. Tarsus IV with three dorsal setae and two PAS. All legs with two lateral claws and one bidentate median claw. Lateral claws with accessory process dorsally. Lateral claws of tarsi II­IV with ventral pecten.</p> <p> <b>Etymology.</b> The species is dedicated in honor of Prof. B. C. Guru, Utkal University, Bhubaneswar, Orissa, India, thesis advisor (in D. Sc.) of first author (TC).</p> <p> <b>Remarks.</b> <i>Copidognathus gurui</i> sp. nov. is characterized by two crescent shaped middle areolae on anterior dorsal plate, ds 2 on anteromedian corner of OC, a swollen telofemur I with a trilobed ventrolateral lamella, tibia I with two denticulate proximoventral processes, tarsi III and IV with 4:3 dorsal setae, telofemora III and IV each with one ventral seta.</p> <p> Present new species has some similarity with <i>C. punctatissimus</i> (Gimbel, 1919), <i>C. dentatus</i> Viets, 1940, <i>C. biscayneus</i> Newell, 1947, <i>C. dentipes</i> Bartsch, 1989, <i>C. eblingi</i> Chatterjee, 1991, <i>C. jejuensis</i> Chatterjee & Chang, 2004 and <i>C. mumbaiensis</i> Chatterjee & Chang, 2004. <i>C. tupinamborum</i> Pepato & Tiago, 2005 (Gimbel 1919; Newell 1947; Bartsch 1989; Chatterjee 1991; Chatterjee and Annapurna 2003, Chatterjee and Chang 2004a, b, 2006; Pepato and Tiago 2005).</p> <p> <i>C. punctatissimus</i> has ds 2 located on anteromedial corner of OC as in <i>C. gurui</i> sp. nov. while in all of the other aforementioned species ds 2 are located in the membranous cuticular area between AD and OC. <i>Copidognathus gurui</i> sp. nov. differs from <i>C. punctatissimus</i> and all other species in having a well developed trilobed ventrolateral lamella on telofemur I.</p> <p> <i>Copidognathus mumbaiensis</i> is characterised by the presence of a serrated lamella ventrolaterally on telofemur I instead of trilobed lamella.</p>Published as part of <i>Chatterjee, Tapas & Pešić, Vladimir, 2014, A new species of the genusCopidognathus (Acari, Halacaridae) from Zanzibar, Tanzania, pp. 169-175 in Ecologica Montenegrina 1 (3)</i> on pages 170-17
Ruminations of a Gandhian: Margaret Chatterjee
No full text This article is based on conversations the author had with nonagenarian Gandhian, Margaret Chatterjee, over the last one year. It is reflective of Chatterjee’s engagement with Gandhian philosophy—non-violence and satyagraha, drawn from influences in Gandhi’s life—and captures why she rejects the categorization of Gandhi as either a traditionalist or a modernist. </jats:p
Interview with Arup K Chatterjee
No full textArup K Chatterjee was awarded his doctorate at the Center for English Studies, Jawaharlal Nehru University, in 2015. He has taught English, as an Assistant Professor, at colleges in the University of Delhi. In 2014-15 he was a recipient of Charles Wallace fellowship to the United Kingdom. He is the founding-chief-editor of Coldnoon: International Journal of TravelWriting & Travelling Cultures <http://www.coldnoon.com/>. He is the author of The Purveyors of Destiny: A Cultural Biography of the Indian Railways (Bloomsbury, 2017). He is an Assistant Professor at the School of Law, O.P. Jindal Global University.</jats:p
Gynodiastylis bacescui Petrescu & Chatterjee, 2011, sp. nov.
No full textG <i>ynodiastylis bacescui</i> sp. nov. <p>(Fig. 2 A–J)</p> <p> <b>Material examined.</b> Holotype manca (MGAB CUM 1689). South Andaman: Wandoor (11°40.55’N, 92°45.12’E), Port Blair, Andaman Islands, intertidal sediments among macroalgae (<i>Padina</i> sp.), December 2005; coll. T. Chatterjee.</p> <p> <b>Diagnosis.</b> Elongated carapace, rounded and large telson, reaching half of uropodal peduncle, basis of maxilliped 3 with one short outer plumose seta, uropodal endopod with three articles.</p> <p> <b>Description.</b> Manca. Body, 3.39 mm in length.</p> <p>Carapace (Fig. 2 B). 0.42 of entire body length, 1.7 longer than high, pseudorostral lobes about 0.34 of frontal lobe, ocular lobe, large, rounded, without any visual elements, distinct antennal notch, slight serrate ventral margin.</p> <p>Pereon. 0.14 of entire body length, first segment hardly visible dorsally.</p> <p>Pleon. 0.5 of entire body length, segments robust.</p> <p>Antenna 1 (Fig. 2 C, D). Short, basal article of peduncle as long as other two articles together, main flagellum with three articles and aesthetascs, accessory flagellum with two articles and one apical sensory seta.</p> <p>Maxilliped 3 (Fig. 2 E). Basis 0.45 times as long as entire maxilliped length, two plumose setae on medial margin, without outer process, ischium with one short plumose seta, merus with one long plumose seta on outer margin, carpus as long as ischium and merus together, with one short plumose seta on outer margin, propodus 1.13 times as long as carpus, two short pappose setae on medial margin, dactylus 1.24 times as long as propodus, with short hairs on medial margin. Exopod, small, with three-articled flagellum.</p> <p>Pereopod 1 (Fig. 2 F). Large basis with serrate medial margin, 3 pappose apical setae, rest of pereopod broken. Exopod 2.25 times as long as exopod of maxilliped 3.</p> <p>Pereopod 2 (Fig. 2 G). Basis 0.32 of entire pereopod length, twice as long as merus, as long as propodus and dactylus together, dactylus 1.15 times as long as propodus. Exopod fully developed.</p> <p>Pereopod 3 (Fig. 2 H). Large articles, basis 0.43 times as long as entire pereopod length, 1.5 times as long as merus, merus second largest article, 2.2 times as long as ischium, 2.7 times as long as carpus, 1.12 times as long as propodus, propodus 1.14 times as long as dactylus, dactylus with short terminal robust curved seta like a claw.</p> <p>Pereopod 4 (Fig. 2 I). Large articles, basis 0.39 times as long as entire pereopod length, merus 2 times as long as ischium, 2.7 times as long as carpus, 1.5 times as long as propodus, propodus 0.8 times as long as dactylus, dactylus with short terminal robust curved seta like a claw.</p> <p>Uropod (Fig. 2 J). Peduncle as long as last pleonite, with strongly serrate medial margin, 1.19 times as long as endopod, exopod 0.6 times as long as endopod, with two articles, one robust curved terminal seta, endopod with three articles, proximal article 1.5 times as long as median article, with robust curved terminal seta. Telson round and large, 0.66 times as wide as last pleonite, 0.52 times as long as uropodal peduncle.</p> <p>Male. Unknown.</p> <p> <b>Etymology.</b> The species is named in honour of Mihai Bäcescu (1908–1999), famous Romanian specialist in Cumacea, and master of the first author (IP).</p> <p> <b>Remarks.</b> G <i>ynodiastylis bacescui</i> <b>sp. nov.</b> resembles <i>G. carinirostris</i> Hale (1946) and <i>G. hartmeyeri</i> Zimmer (1914), both of them recorded from New South Wales, Bass Strait (Australia), in having a carapace much longer than high and a uropodal endopod with three articles. It differs from <i>G. carinirostris</i> by lacking visual elements and from <i>G. hartmeyeri</i> by having a more rounded telson. Such a round telson can also be found in <i>G. fulgida</i> Day (1980) and <i>G. profunda</i> Day (1980), both from South Africa and with a uropodal endopod with one article and in <i>G. blax</i> Gerken (2001) from South Australia (with a shorter telson than the new species from Andaman and a uropodal endopod with two articles). <i>G. bacescui</i> <b>sp. nov.</b> differs from all of these species in having the basis of maxilliped 3 with a short plumose outer seta (in contrast with three or four outer setae in the other above-mentioned species) and especially by its enlarged merus of pereopod 3. This is the first record of the genus <i>Gynodiastylis</i> from India.</p>Published as part of <i>Petrescu, Iorgu & Chatterjee, Tapas, 2011, New species and new records of cumaceans (Crustacea: Peracarida: Cumacea) from the Andaman Islands, Indian Ocean, pp. 51-57 in Zootaxa 2966</i> on pages 55-56, DOI: <a href="http://zenodo.org/record/201857">10.5281/zenodo.201857</a>
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