Using the Hadamard and related transforms for simplifying the spectrum of the quantum baker's map

We rationalize the somewhat surprising efficacy of the Hadamard transform in simplifying the eigenstates of the quantum baker's map, a paradigmatic model of quantum chaos. This allows us to construct closely related, but new, transforms that do significantly better, thus nearly solving for many states of the quantum baker's map. These new transforms, which combine the standard Fourier and Hadamard transforms in an interesting manner, are constructed from eigenvectors of the shift permutation operator that are also simultaneous eigenvectors of bit-flip (parity) and possess bit-reversal (time-reversal) symmetry.Comment: Version to appear in J. Phys. A. Added discussions; modified title; corrected minor error

Spawning periodicity of the ribbon fish, Trichiurus lepturus (F.), with a note on its rate of growth

The spawning periodicity of Trichiurus lepturus is briefly re-examined here in tlie light of certain recent observations. It is seen that this species spawns more than once in a year along the Madras coast and the two seasons are roughly around May-June and later in November-December. This fact also leads to a revision in the interpretation of the rate of growth of the fish. It is now estimated that the fish at the end of one year attains an average of 300 mm in length and that those above about 900 mm are just over four years

Coastal Aquaculture - Mussel farming; Progress and prospects

During the seventies, the Central Marine Fisheri^ lleseardi Institute gave a lead in researches on mariculture and has carved for itself a pioneering role in the R& D programmes of mariculture in the countiy which has been well recognised. Impressed by the outstanding contributions made during the decade, the infrastructure facilities built up and, above all, the scientific and techni<ial competence it has acquittdi jm UNDP/ICAR Centre of Advanced Studies in Mariculture has been instituted at the Central Marine Fisheries Research Institute since June 1979. The Centre aims at providing postgraduate education in the new discipline of Mariculture and improvmg the quality of research through doct(»ral and post-doctoral research programmes in identified areas. One of the priority areas of mariculture in India is mussel culture. Although considered a poor relation of the oyster in Europe, mussel has one of the highest potentials in India for increaang production of protein- rich sea food. Mussel gives the highest conversion of primary producera ^hytojrfankton) to human food and culture production in column waters enhances the yield several fold. India has a traditional sustenance fishery for the mmsels at a few centres but the scope for increasing natural production from the existing beds is rather limited

The present status of ribbonfish fishery in India

The ribbonfishes, of the family TrichiurkJae, an Important group of food fishes in India, registered an average annual catch of 53.475 tonnes during 1970-81. In this period, forming 4.25% of the total marine fish catch, thsy formed the 7th exploited fish group in the order of predominance. There are 8 known ribbonfish species in India (an identification key to the species is given in the beginning of thearticle) The information available on the various aspects of biology of each of these species is summarised, which clearly indicates that while our knowledge on the biology of Trichiurus lepturua, Lepturecanthus savale, Eupleurogrammus nwticus and Eupleurogrammus glossodon is considereble, we know little about the other species. Traditionally, the ribbonfishes are caught by boatseines, shoreseines, bag nets and gill nets, operating from nonpowered country crafts. But, during the last two decades, the small mechanized vessels (10-15 m long, with 15-100 hp engines) that are operating otter trawls, too, are increasingly landing ribbonfish. The fishery is confined to the depth-zone usually shallower than 50 m. T. lepturus, the most widely distributed, forms the mainstay of the ribbonfish fishery, contributing to the bulk of the landings along almost all our coastline. Data on spatial and seasonal variations in abundance, size and age composition in the commercial catches and diurnal movements and depthwise distributions of shoals of this species are therefore reviewed. Stock assessment studies show that, in the shelf region from Ratnagiri on the west coast round to Gulf of Mannar on the east, there had been an average standing stock of 67,200 tonnes of ribbonfish (mostly L Lepturus) in 1972-75, which is about 4 times what was actually landed from the region during the period. It therefore follows that a doubling of the catch will not adversely affect the stock in the region. Studies on the population dynamics of T. lepturus from the Kakinada area during 1967-71 has shown that the fishing mortality and the exploitation rates are low, at 0.3 and 0.17 respectively. The average annual stock and average standing stock along the Andhra and Tamil Nadu coasts are estimated at 85,000 and 48,000 tonnes, respectively, for T. lepturus, against an estimated annual average catch of 14,400 tonnes during 1967-71. It thus appears that the stock of T. lepturus along the east coast also is likewise underfishad, The need for extension of fishing operations into the Exclusive Economic Zone with larger vessels, equipped with suitable gears like bottom and pelagic trawls, is emphasized- Suggestions on future lines of research are given

Industrial fisheries off Madras coast based on exploratory surveys during 1973-1980

At the Madras Research Centre of CMFRI, there existed data for areas (Fig. 1) south of 15°40'N Upto the latitude zone of I0°40'N off Velanganni in depths ranging from 10 to 130 m for a eight year period From 1973 to 1980. The results of analysis of these data are presented here with a view to providing information on and extending our knowledge about the spatial and seasonal distribution of various indusirially important fisheries as also their resource potential along the north Tamil Nadu-South Andhra Coast

Antiplatelet therapy with aspirin, clopidogrel, and dipyridamole versus clopidogrel alone or aspirin and dipyridamole in patients with acute cerebral ischaemia (TARDIS): a randomised, open-label, phase 3 superiority trial

Background: Intensive antiplatelet therapy with three agents might be more effective than guideline treatment for preventing recurrent events in patients with acute cerebral ischaemia. We aimed to compare the safety and efficacy of intensive antiplatelet therapy (combined aspirin, clopidogrel, and dipyridamole) with that of guideline-based antiplatelet therapy. Methods: We did an international, prospective, randomised, open-label, blinded-endpoint trial in adult participants with ischaemic stroke or transient ischaemic attack (TIA) within 48 h of onset. Participants were assigned in a 1:1 ratio using computer randomisation to receive loading doses and then 30 days of intensive antiplatelet therapy (combined aspirin 75 mg, clopidogrel 75 mg, and dipyridamole 200 mg twice daily) or guideline-based therapy (comprising either clopidogrel alone or combined aspirin and dipyridamole). Randomisation was stratified by country and index event, and minimised with prognostic baseline factors, medication use, time to randomisation, stroke-related factors, and thrombolysis. The ordinal primary outcome was the combined incidence and severity of any recurrent stroke (ischaemic or haemorrhagic; assessed using the modified Rankin Scale) or TIA within 90 days, as assessed by central telephone follow-up with masking to treatment assignment, and analysed by intention to treat. This trial is registered with the ISRCTN registry, number ISRCTN47823388. Findings: 3096 participants (1556 in the intensive antiplatelet therapy group, 1540 in the guideline antiplatelet therapy group) were recruited from 106 hospitals in four countries between April 7, 2009, and March 18, 2016. The trial was stopped early on the recommendation of the data monitoring committee. The incidence and severity of recurrent stroke or TIA did not differ between intensive and guideline therapy (93 [6%] participants vs 105 [7%]; adjusted common odds ratio [cOR] 0·90, 95% CI 0·67–1·20, p=0·47). By contrast, intensive antiplatelet therapy was associated with more, and more severe, bleeding (adjusted cOR 2·54, 95% CI 2·05–3·16, p<0·0001). Interpretation: Among patients with recent cerebral ischaemia, intensive antiplatelet therapy did not reduce the incidence and severity of recurrent stroke or TIA, but did significantly increase the risk of major bleeding. Triple antiplatelet therapy should not be used in routine clinical practice

Multiple effects of toxins isolated from Crotalus durissus terrificus on the hepatitis C virus life cycle

Hepatitis C virus (HCV) is one of the main causes of liver disease and transplantation worldwide. Current therapy is expensive, presents additional side effects and viral resistance has been described. Therefore, studies for developing more efficient antivirals against HCV are needed. Compounds isolated from animal venoms have shown antiviral activity against some viruses such as Dengue virus, Yellow fever virus and Measles virus. In this study, we evaluated the effect of the complex crotoxin (CX) and its subunits crotapotin (CP) and phospholipase A2 (PLA2-CB) isolated from the venom of Crotalus durissus terrificus on HCV life cycle. Huh 7.5 cells were infected with HCVcc JFH-1 strain in the presence or absence of these toxins and virus was titrated by focus formation units assay or by qPCR. Toxins were added to the cells at different time points depending on the stage of virus life cycle to be evaluated. The results showed that treatment with PLA2-CB inhibited HCV entry and replication but no effect on HCV release was observed. CX reduced virus entry and release but not replication. By treating cells with CP, an antiviral effect was observed on HCV release, the only stage inhibited by this compound. Our data demonstrated the multiple antiviral effects of toxins from animal venoms on HCV life cycle

Review on catalytic cleavage of C-C inter-unit linkages in lignin model compounds: Towards lignin depolymerisation

Lignin depolymerisation has received considerable attention recently due to the pressing need to find sustainable alternatives to fossil fuel feedstock to produce chemicals and fuels. Two types of interunit linkages (C–C and C–O linkages) link several aromatic units in the structure of lignin. Between these two inter-unit linkages, the bond energies of C–C linkages are higher than that of C–O linkages, making them harder to break. However, for an efficient lignin depolymerisation, both types of inter-unit linkages have to be broken. This is more relevant because of the fact that many delignification processes tend to result in the formation of additional C–C inter-unit bonds. Here we review the strategies reported for the cleavage of C–C inter-unit linkages in lignin model compounds and lignin. Although a number of articles are available on the cleavage of C–O inter-unit linkages, reports on the selective cleavage of C–C inter-unit linkages are relatively less. Oxidative cleavage, hydrogenolysis, two-step redox-neutral process, microwave assisted cleavage, biocatalytic and photocatalytic methods have been reported for the breaking of C–C inter-unit linkages in lignin. Here we review all these methods in detail, focused only on the breaking of C–C linkages. The objective of this review is to motivate researchers to design new strategies to break this strong C–C inter-unit bonds to valorise lignins, technical lignins in particular

Chem4Energy: a consortium of the Royal Society Africa Capacity-Building Initiative

The Africa Capacity-Building Initiative is a Royal Society programme funded by the former UK Department for International Development to develop collaborative research between scientists in sub-Saharan Africa and the UK. Initially, four institutions were involved in the Chem4Energy consortium: Cardiff University in the UK and three African partners, the Kwame Nkrumah University of Science and Technology, Ghana, the University of Namibia and the University of Botswana, soon also including the Botswana International University of Science and Technology. The Chem4Energy research programme focused on ‘New materials for a sustainable energy future: linking computation with experiment’, aiming to deploy the synergy between state-of-the-art computational and experimental techniques to design and optimize new catalysts and semiconductor materials for renewable energy applications, based on materials that are abundant and readily available in African countries. The Chem4Energy consortium has achieved ambitious research goals, graduated seven PhD students and delivered a high-quality cross-disciplinary training programme in materials science and simulation techniques relevant to renewable energy applications. Since 2021, the extended consortium, including North-West University and the Centre for High-Performance Computing in South Africa, has remained active through an annual Chem4Energy conference series, with the sixth meeting taking place in Namibia in April 2025