BUILDING CONSENSUS FOR SUSTAINABLE DEVELOPMENT IN AQUACULTURE: A DELPHI STUDY OF BETTER MANAGEMENT PRACTICES FOR SHRIMP FARMING IN INDIA     

Diego Valderrama  Sivaraman Iyemperumal  M. Krishnan 《Aquaculture Economics & Management (Blackwell Science)》2013,17(4):369-394

Shrimp farming in India has developed at an uneven pace since export-oriented production began in the early 1990s. The introduction of Penaeus vannamei in 2009 along with disease-related production declines in competing Asian nations has led to a remarkable expansion in recent years. It is clear that the long-term success of Indian shrimp farming will continue to rely on the widespread adoption of Better Management Practices (BMPs). A two-round stakeholder Delphi survey was conducted in 2012 to elicit views and build consensus on the relative importance of a comprehensive set of BMPs covering most aspects of shrimp farming production. While the vast majority of BMPs were considered important, respondents placed greater emphasis on those BMPs aimed at improving production efficiency. Also, BMPs focused on overall outcomes were ranked higher than those placing specific restrictions on input usage. Results also yielded interesting policy implications on BMPs that are yet to be widely adopted such as distance between farms and construction of effluent treatment systems.  相似文献   

Accumulation of Cadmium and Antioxidant and Hormonal Responses in the Indian Major Carp <Emphasis Type="Italic">Cirrhinus mrigala</Emphasis> During Acute and Sublethal Exposure     

Annamalai Malarvizhi  Manoharan Saravanan  Rama Krishnan Poopal  Jang-Hyun Hur  Mathan Ramesh 《Water, air, and soil pollution》2017,228(8):310

Acute (24 h) and sublethal (35 days) effects of cadmium chloride (CdCl₂) were examined in Cirrhinus mrigala using various endpoints (accumulation pattern, thyroid hormones (THs), and antioxidants). The mean concentrations of CdCl₂ for 24 and 96 h were found to be 35.974 and 22.387 mg L^?l, respectively. LC50 concentration of CdCl₂ for 24 h (35.97 mg L^?l) was used for the acute study. For the sublethal studies, fish were exposed to 3.59 mg L^?1 (Treatment I) and 7.19 mg L^?1 (Treatment II) corresponding to 1/10th and 1/5th of 24 h LC50 of the CdCl₂. During acute exposure, higher accumulation of CdCl₂ was noticed in the gill, liver, and kidney of C. mrigala, which is found in the order gill > liver > kidney tissues. Similarly, in sublethal treatments (Treatment I and II), a concentration and time-dependent increase of CdCl₂ accumulation was noticed in the order of gill > liver > kidney. GSH, GST, and GPx activities were found to be relatively lower from the treated groups in both acute and sublethal treatments. However, LPO activity was significantly increased in CdCl₂-treated fish C. mrigala. Further, plasma T₃ reduction was more pronounced than T₄ in acute study. During sublethal treatments, both T₄ and T₃ levels showed a continuous decrease as the exposure period extended. All the values in this study were statically significant (P < 0.01 and P < 0.05).  相似文献   

Influence of Damping on the Bending and Twisting Modes of Flax Fibre-reinforced Polypropylene Composite     

Md Zillur Rahman  Krishnan Jayaraman  Brian Richard Mace 《Fibers and Polymers》2018,19(2):375-382

The effects of damping on the bending and twisting modes of flax fibre-reinforced polypropylene composites are investigated. The laminate was manufactured by a vacuum bagging process; its dynamic behaviour was then found from the vibration measurements of a beam test specimen using an impulse hammer technique to frequencies of 1 kHz. The frequency response of a sample was measured, and the bending and twisting responses at resonance were used to estimate the natural frequency and loss factor. The single-degree-of-freedom circle-fit method and Newton’s divided differences formula were used to estimate the natural frequencies as well as the loss factors. The damping estimates were also investigated using a “carpet” plot. The results show significant variations in loss factors depending on the type of mode. The loss factor generally lies in the range of 1.7-2.2 % for the bending modes, while 4.8 % on average for the twisting modes. Numerical estimates of the response, and in particular the natural frequencies, were made using a Mechanical APDL (ANSYS parametric design language) finite element model, with the beam being discretised into a number of shell elements. The natural frequencies from the finite element analysis show reasonably good agreement (errors < 5 %) with the measured natural frequencies.  相似文献   

Effects of mutual shading of tree crowns on prediction of photosynthetic light-use efficiency in a coastal Douglas-fir forest     

Hilker T  Coops NC  Schwalm CR  Jassal RS  Black TA  Krishnan P 《Tree physiology》2008,28(6):825-834

Gross primary production (GPP) is often expressed as the product of absorbed photosynthetically active radiation and the efficiency (epsilon) with which a plant community uses absorbed radiation in biomass production. Light-use efficiency is affected by environmental stresses, and varies diurnally and seasonally. Uncertainty about epsilon can be a serious limitation when modeling GPP. An important determinant of epsilon is the amount and type of solar radiation incident on a canopy, because an abundance of light can trigger a photo-protective reaction, diminishing GPP. The radiation regime in a forest canopy is determined by the predominant sky conditions and by mutual shading of tree crowns. Shading effects, producing shifts in the amount of incident direct and diffuse solar radiation, have been largely ignored, however, because they depend on forest structure and are difficult to measure. We describe a new approach for estimating changes in mutual canopy shading throughout the day and year based on a canopy structure model derived from light detection and ranging (LiDAR). Proportions of canopy shading were then combined with eddy covariance data to assess the explanatory power for variance in epsilon by regression tree analysis over half-hourly, daily and weekly time scales. The approach explained between 75 and 97% of variance in epsilon, representing an increase of between 5 and 16% compared with models driven solely by meteorological variables.  相似文献   

The dynamics of zooxanthellae populations: A long-term study in the field   总被引：1，自引：0，他引：1  

I Fagoonee  HB Wilson  MP Hassell  JR Turner 《Science (New York, N.Y.)》1999,283(5403):843-845

Coral bleaching characterized by the expulsion of symbiotic algae (zooxanthellae) is an increasing problem worldwide. Global warming has been implicated as one cause, but the phenomenon cannot be fully comprehended without an understanding of the variability of zooxanthellae populations in field conditions. Results from a 6-year field study are presented, providing evidence of density regulation but also of large variability in the zooxanthellae population with regular episodes of very low densities. These bleaching events are likely to be part of a constant variability in zooxanthellae density caused by environmental fluctuations superimposed on a strong seasonal cycle in abundance.  相似文献   

Cross impact analysis and data mining variable hierarchy of stakeholder responses for sustainable development of Schizothorax fisheries in Kashmir lakes,India     

Neha W. Qureshi  M. Krishnan  Ramasubramanian V. 《Fisheries Management and Ecology》2020,27(2):132-139

This study documented the history of lake fisheries in Kashmir, India, and estimated the trends in fish production using Kane's cross impact analysis (CIA) and stakeholders’ willingness to pay (WTP) for the restoration of the Schizothorax fisheries. Kane's CIA model for Lake Dal indicated a perceptible drop in Schizothorax production in the long run, and that the total catch is being maintained by an increasing contribution by carp. In Lake Wular, the CIA indicated that the size of the lake still offers scope for the co‐existence and growth of both Schizothorax as well as carp. A Classification and Regression Tree (CART) model was used to data mine multiple stakeholder responses to make a case for sustainable development of the Schizothorax fisheries in the lakes of Kashmir. The amount of time spent on the lakes to earn their livelihoods emerged as the single most important variable that determined WTP by stakeholders followed by income, type of stakeholder and age. The pruned tree gave the hierarchy of the variables that determined WTP. The results made a strong case for a concerted multi‐institutional action plan for the restoration of the Schizothorax fisheries in the lakes of Kashmir.  相似文献   

Molecular detection of WA‐CMS restorers from tropical japonica‐derived lines,their evaluation for fertility restoration and adaptation     

Shivakumar Shidenur  Vikram Jeet Singh  Kunnummal Kurungara Vinod  Subbaiyan Gopala Krishnan  Surendra Kumar Ghritlahre  Haritha Bollinedi  Ranjith K. Ellur  Brijesh Kumar Dixit  Binder Singh  Mariappan Nagarajan  Ashok Kumar Singh  Prolay Kumar Bhowmick 《Plant Breeding》2019,138(5):553-567

Hybrid rice based on wild‐abortive cytoplasmic male sterility (WA‐CMS) is important in boosting rice production, which requires diverse parents to harness heterosis. For this, exploiting the diversity of japonica through tropical japonica (TRJ) lines is an excellent route. In this study, 310 TRJ‐based new plant type (NPT) lines were developed and evaluated for Rf3 and Rf4 genes. Gene‐based (DRRM‐Rf3‐5 and DRRM‐Rf3‐10) and functional marker (RMS‐SF21‐5) targeted Rf3 locus, while gene‐linked (RM6100) and functional marker (RMS‐PPR9‐1) targeted the Rf4 locus. The frequency of the restorer allele of Rf3 gene was lower when compared to that of Rf4. Combined phenotypic and molecular screening using gene‐based and functional markers identified 42 lines that carried Rf3 and/or Rf4 genes. All the selected lines produced fertile F₁s when crossed to a WA‐CMS line, “Pusa 6A”, but with varying levels of spikelet fertility. This is the first report of a marker‐cum‐phenotype‐based restorer selection using TRJ‐derived lines. Multilocation evaluation of these lines at three locations indicated better adaptation for grain yield in some of the lines.  相似文献   

The host background of rice influences the resistance expression of a three genes pyramid (xa5 + xa13 + Xa21) to bacterial blight (Xanthomonas oryzae pv. oryzae) pathotypes of Indian mainland and Bay islands          下载免费PDF全文

Krishnan Sakthivel  Raj K. Gautam  Kaari Manigundan  Reena Singh  Jegadeesan Ramalingam  Gouri S. Laha  Aundy Kumar  Rethinasamy Velazhahan 《Plant Breeding》2017,136(3):357-364

Bacterial blight (BB) is a major disease of rice for which host resistance is the only effective solution. The three genes pyramid xa5 + xa13 + Xa21 is recently the most utilized combination for developing resistant varieties through marker‐assisted breeding. Our study was carried out to elicit the detailed response of twenty lines possessing these three genes in five genetic backgrounds to twelve diverse BB pathotypes in India. The lines developed from ADT 47 variety showed incomplete resistance to most of the pathotypes, whereas susceptibility varied from 8.3% to 16.6% in ADT 43 and IR24, respectively. However, in IMP ASD16/60 and Improved Samba Mahsuri, complete resistance against all pathotypes was observed. The overall results confirmed that genetic background plays crucial role for the effective expression of xa5 + xa13 + Xa21 combination. Molecular studies did not reveal correlation between origin of pathotypes and their virulence potential. It is suggested to deploy Improved Samba Mahsuri, IMP ASD 16/60 and AD1306 varieties in the bacterial blight prone areas or use them as donors for realizing wider and durable resistance.  相似文献   

Enhanced grain yield in rice hybrids through complementation of fertility restoration by Rf3 and Rf4 genes as revealed by multilocation evaluation of tropical japonica derived rice (Oryza sativa) hybrids     

Shivakumar Shidenur  Vikram Jeet Singh  Kunnummal Kurungara Vinod  S Gopala Krishnan  Surendra Kumar Ghritlahre  Haritha Bollinedi  Brijesh Kumar Dixit  Ranjith Kumar Ellur  Mariappan Nagarajan  Ashok Kumar Singh  Prolay Kumar Bhowmick 《Plant Breeding》2020,139(4):743-753

Thirty-one tropical japonica derived Rf gene carrying rice hybrids were classified into three classes as Rf3, Rf4 and Rf3 + Rf4 hybrids. These hybrids were tested under three different mega-environments. Between Rf3 class and both the classes of hybrids possessing Rf4 genes, significant variation for spikelet and pollen fertility and grain yield was found. The pollen fertility was five times higher among Rf4 hybrids than that of hybrids carrying Rf3 alone. Likewise, spikelet fertility among Rf4 hybrids was two times higher than that of Rf3 hybrids. Parallel grain yield increase in Rf4 hybrids was 2.4 times than in Rf3 hybrids. However, Rf3 gene was found complementing Rf4 to truncate the range of pollen and spikelet fertility. Hybrids possessing Rf3 alone exhibited partial pollen and spikelet sterility, and significant negative standard heterosis for grain yield. The high yielding hybrid, “HYB36” carrying both the Rf genes was found to be widely adapted. The present study established that Rf4 gene is essential either alone or in combination with Rf3 for fertility restoration to achieve enhanced grain yield in WA-CMS based hybrids.  相似文献   

Typing of Staphylococcus aureus isolated from bovine mastitis cases in Australia and India          下载免费PDF全文

J Gogoi‐Tiwari  C Babra Waryah  R Sunagar  HB Veeresh  V Nuthanalakshmi  PL Preethirani  R Sharada  S Isloor  A Bhat  H Al‐Salami  NR Hegde  TK Mukkur 《Australian veterinary journal》2015,93(8):278-282

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