What we don't know about time

String theory has transformed our understanding of geometry, topology and spacetime. Thus, for this special issue of Foundations of Physics commemorating "Forty Years of String Theory", it seems appropriate to step back and ask what we do not understand. As I will discuss, time remains the least understood concept in physical theory. While we have made significant progress in understanding space, our understanding of time has not progressed much beyond the level of a century ago when Einstein introduced the idea of space-time as a combined entity. Thus, I will raise a series of open questions about time, and will review some of the progress that has been made as a roadmap for the future.Comment: 15 pages; Essay for a special issue of Foundations of Physics commemorating "Forty years of string theory

Occurrence of the deep sea crab, Thalamita crenata in shallow water gillnet (mural valai) operation at Tharuvaikulam, north of Tuticorin

The deep sea crab, Thalamita crenata mostly inhabit only deeper waters (>100 m) and occur in deep sea gillnet operations along with fishes like hemiramphids, belonids and Exocetus spp. as stray catches. It never formed a fishery and did not gain any economical importance

Innovative method of processing crabs at landing centre

A sizable number of fisherfolk diverted theirfishing effort for crab fishery. Better catch of crabs urged the processors to adopt indigenous processing technology. The crabs are first sorted out species-wise and quality-wise for processing

Primary productivity of some sea grass beds in the Gulf of Mannar

Primary productivity of two seagrass beds and one algal bed in the Gulf of Mannar was studied by diurnal curve method. The sea grass bed close to Mandapam Camp was found to be autotrophic, with P/R ratios ranging from 1.65 to 3.90. The seagrass and algal beds around Kurusadai island were heterotrophic. Production of oxygen by individual sea grasses equalled or exceeded their consumption

Information Recovery From Black Holes

We argue that if black hole entropy arises from a finite number of underlying quantum states, then any particular such state can be identified from infinity. The finite density of states implies a discrete energy spectrum, and, in general, such spectra are non-degenerate except as determined by symmetries. Therefore, knowledge of the precise energy, and of other commuting conserved charges, determines the quantum state. In a gravitating theory, all conserved charges including the energy are given by boundary terms that can be measured at infinity. Thus, within any theory of quantum gravity, no information can be lost in black holes with a finite number of states. However, identifying the state of a black hole from infinity requires measurements with Planck scale precision. Hence observers with insufficient resolution will experience information loss.Comment: First prize in the Gravity Research Foundation Essay Competition, 8 pages, Late

मान्नार की खाडी में टूटिकोरिन तट पर यूथिनस अफिनिस (कान्टर) और सार्डा ओरिएन्टालिस (टेम्मिंक और शीयगल) की किशोर मात्स्यिकी

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स्क्रोम्ब्रोइडस के विशेष प्रसंग में कालिकट की अपवाही जाल मात्स्यिकी

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मान्नार की खाडी में टूटिकोरिन तट पर जेम्पिलिडे कुल की मछलियों की मात्स्यिकी

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On the juvenile fishery of Euthynnus affinis and Sarda orientalis along the Tuticorin Coast in Gulf of Mannar

An estimated 2882 t of tuna were landed by gillnets and hook and line at Tuticorin duringthe year 2006. They were exploited by smallmeshed gillnets locally known as podivalai with 3.3 to 7.5 cm mesh size, large meshed gillnets known as paruvalai with 8-16 cmmesh size and hooks and line operated from mechanized boats and motorized vallams.Small meshed gillnets operate in shallow waters within 10-15 m depth and land tunas along with other medium sized pelagics.Podivalai accounted for 8.3% tuna landings.Large meshed gillnets and hooks and line operate in 50-150 m depth zone beyond 10 km from the coast and land large tunas and pelagics. Large meshed gillnets contributed 90.3% of the total tuna catch

मान्नार खाडी की वेलापवतीं समुद्री संपदाओं का प्रबंधन

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