A Lagrangian relaxation approach to the edge-weighted clique problem

The $b$-clique polytope $CP^n_b$ is the convex hull of the node and edge incidence vectors of all subcliques of size at most $b$ of a complete graph on $n$ nodes. Including the Boolean quadric polytope $QP^n$ as a special case and being closely related to the quadratic knapsack polytope, it has received considerable attention in the literature. In particular, the max-cut problem is equivalent with optimizing a linear function over $QP^n_n$. The problem of optimizing linear functions over $CP^n_b$ has so far been approached via heuristic combinatorial algorithms and cutting-plane methods. We study the structure of $CP^n_b$ in further detail and present a new computational approach to the linear optimization problem based on Lucena's suggestion of integrating cutting planes into a Lagrangian relaxation of an integer programming problem. In particular, we show that the separation problem for tree inequalities becomes polynomial in our Lagrangian framework. Finally, computational results are presented. \u

Skewed sex ratio in an estuarine lobster (Homarus americanus) population

A total of 19,485 lobsters were caught sites in the estuarine and coastal waters of New Hampshire from 1989 to 1992, and their size and sex were determined. The sex ratio of lobsters caught farthest from the coast, in Great Bay, was heavily skewed in favor in males. Sex ratios in other estuarine and river sites were also skewed toward males, and there was a tendency for the number of males per female to decline as one moved down the estuary toward the coast, where the sex ratio was nearly 1:1. The single offshore site was dominated by females, with about 0.6 males for each female. There were also seasonal trends in the sex ratios in the upper estuarine sties, where the number of males per female tended to decline from summer through autumn. In general, differences in the sex ratios between sites were those of primarily adult lobsters larger than 80 mm carapace length (CL). At all sites, the sex ratio of lobsters smaller than this size was close to 1:1, whereas in the upper estuary the mean sex ratio of lobsters greater than 80 mm CL was more than 14:1. These data, in conjunction with seasonal variations of sex ratios, suggest that differential movements of adult male and female lobsters is the primary cause of skewed sex ratios in the Great Bay Estuary

Preliminary assessment of illegal hunting by communities adjacent to the northern Gonarezhou National Park, Zimbabwe

Illegal hunting of wildlife is a major issue in today’s society, particularly in tropical ecosystems. In this study, a total of 114 local residents from eight villages located in four wards adjacent to the northern Gonarezhou National Park, south-eastern Zimbabwe were interviewed in 2009, using semi-structured questionnaires. The study aimed to answer the following questions: (i) what is the prevalence of illegal hunting and what are commonly used hunting methods? (ii) Which wild animal species are commonly hunted illegally? (iii) What are the main reasons for illegal hunting? (iv) What strategies or mechanisms are currently in place to minimize illegal hunting? Overall, 59% of the respondents reported that they saw bushmeat, meat derived from wild animals, and/or wild animal products being sold at least once every six months, whereas 41% of the respondents reported that they had never seen bushmeat and/or wild animal products being sold in their villages and/or wards. About 18% of the respondents perceived that illegal hunting had increased between 2000 and 2008, whereas 62% of the respondents perceived that illegal hunting had declined, and 20% perceived that it remained the same. Snaring (79%) and hunting with dogs (53%) were reportedly the most common hunting methods. A total of 24 wild animal species were reportedly hunted, with African buffalo (Syncerus caffer) (18%), Burchell’s zebra (Equus quagga) (21%), kudu (Tragelaphus strepsiceros) (25%) and impala (Aepyceros melampus) (27%) amongst the most targeted and preferred animal species. In addition, large carnivores, including spotted hyena (Crocuta crocuta) (11%), leopard (Panthera pardus) (10%) and African lion (Panthera leo) (8%), were reportedly hunted illegally. The need for bushmeat, for household consumption (68%), and raising money through selling of wild animal products (55%) were reported as being the main reasons for illegal hunting. Strengthening law enforcement, increasing awareness and environmental education, and developing mechanisms to reduce human-wildlife conflicts will assist in further minimizing illegal hunting activities in the Gonarezhou ecosystem

Sustainable hunting tourism - business opportunity in Northern areas? Overview of hunting and hunting tourism in four Northern countries: Finland, Sweden, Iceland and Canada

The social sustainability and fluent co-operation with the interest groups is perhaps the most crucial issue related to the development of hunting tourism at the moment. Due to the wide public huntings rights and intensive hunting club ativities in Northern countries, one of the key elements for the success of the hunting tourism company is a good co-operation with the local population and more widely, understanding on the local hunting culture and rights of the local people related to that. Also the ecological sustainability is a core value of hunting tourism. The biological resources set the framework for the enterpreneual activities and e.g. cause the seasonal nature to the activities

Hunting Elephants

MP4 video‘Hunting Elephants’ was told by Rgyal mtshan in A mdo Tibetan. Rta rgyugs, a subdivision of Rka phug Administrative Village, is a farming village located in Khams ra Town, Gcan tsa County Town, Rma lho Tibetan Autonomous Prefecture, Qinghai Province, PR China. In 2010, there were 15 Han Chinese households and 18 Tibetan households in Rta rgyugs Village. The total population was 175 residents (33 households). Most Han Chinese residents were fluent in Tibetan and communicated in Tibetan with local Tibetan villagers. རྐ་ཕུག་སྡེ་བའི་ཁོངས་སུ་གཏོགས་པའི་རྟ་རྒྱུགས་སྡེ་བ་ནི་ཞིང་ལས་གཙོ་བོར་གཉེར་བའི་བོད་སྡེ་ཞིག་ཡིན་ལ། དེ་ནི་ཁམས་ར་གྲོང་བརྡལ་དུ་ཆགས་ཤིང་གཅན་ཚ་རྫོང་མཁར་དང་བར་ཐག་སྤྱི་ལེ་༣༥ ལྷག་ཡོད། གཅན་ཚ་རྫོང་ནི་ཀྲུང་གོའི་མཚོ་སྔོན་ཞིང་ཆེན་རྨ་ལྷོ་བོད་རིགས་རང་སྐྱོང་ཁུལ་གྱི་རྫོང་བཞིའི་ཡ་གྱལ་ཞིག་ཡིན་ཏེ། ༢༠༡༠ལོར་རྟ་རྒྱུགས་སྡེ་བར་བསྡོམས་པས་ཁྱིམ་ཚང་སུམ་ཅུ་སོ་གསུམ་ཡོད་ལ། དེའི་གྲས་སུ་ཁྱིམ་ཚང་བཅོ་ལྔ་ནི་རྒྱ་རིགས་ཡིན་པ་དང་། ཁྱིམ་ཚང་བཅོ་བརྒྱད་བོད་རིགས་ཡིན། རྒྱའི་མི་ཁྱིམ་ཕལ་ཆེ་བས་བོད་སྐད་བཤད་ཤེས་པ་དང་དུས་རྒྱུན་དུ་བོད་སྐད་བཀོད་སྤྱོད་བྱས་ནས་སྡེ་བའི་ནང་གི་བོད་མི་ཚོར་འབྲེལ་འདྲིས་བྱེད། ད་ལྟ་རྟ་རྒྱུགས་སྡེ་བར་འདུས་སྡོད་བྱེད་པའི་མི་གྲངས་ ༡༧༥ཡིན། Rka phug sde ba'i khongs su gtogs pa'i rta rgyugs sde ba ni zhing las gtso bor gnyer ba'i bod sde zhig yin la/ de ni khams ra grong brdal du chags shing gcan tsha rdzong mkhar dang bar thag spyi le 35 lhag yod/ gcan tsha rdzong ni krung go'i mtsho sngon zhing chen rma lho bod rigs rang skyong khul gyi rdzong bzhi'i ya gyal zhig yin te/ 2010 lor rta rgyugs sde bar bsdoms pas khyim tshang sum cu so gsum yod la/ de'i gras su khyim tshang bco lnga ni rgya rigs yin pa dang/ khyim tshang bco brgyad bod rigs yin/ rgya'i mi khyim phal che bas bod skad bshad shes pa dang dus rgyun du bod skad bkod spyod byas nas sde ba'i nang gi bod mi tshor 'brel 'dris byed/ da lta rta rgyugs sde bar 'dus sdod byed pa'i mi grangs 175yin

A Profile of Today's Hunter - Social and Economic Highlights

This edition condenses the findings of the latest studies examining hunters and hunting in America and the social, political and economic necessity of hunting in today's world

2005/2006 Iowa Hunting and Trapping Regulations, 2006-2007

This booklet is not a complete set of hunting laws. It contains basic information needed during the hunting and trapping seasons

Determinants of Demand for Participation in Wildlife Hunting: A County level Analysis

We developed an economic demand model of wildlife hunting and found that sociodemograpahic and ecological characteristics of county are its strong predictors. Result shows that the hunting is not popular among younger generation; and promoting hunting clubs and lease-hunting, recruiting young hunters could be effective policy considerations for retaining/promoting hunting.Wildlife hunting, License sales, Demand model, Resource /Energy Economics and Policy, Q21, Q26, L83,