We consider knowledge representation (KR) formalisms as collections of finite knowledge bases with a model-theoretic semantics. In this setting, we show that for every KR formalism there is a formalism that characterizes strong equivalence in the original formalism, that is unique up to isomorphism and that has a model theory similar to classical logic.

Sexual dimorphism is one of the most widespread and recognizable patterns of phenotypic variation in the biotic world. Sexual dimorphism in floral display is striking in the dioecious plant Silene latifolia, with males making many, small flowers compared to females. We investigated this dimorphism via artificial selection on two populations to determine whether genetic variation exists within p...

The use of natural products as medicinal agents presumably predates the earliest recorded history. Ocimum sanctum L., is a plant which is used in several traditional medicine systems to cure various diseases. In this study aerial parts of Ocimum sanctum were collected on august 2014 from Shahr-e-Rey in Iran. Fresh and dry partsof plants essential oils were extracted with hydro-distillation and ...

Background & Aim: German chamomile is one of the most important medicinal plants. So, assessment of genetic diversity and relationship among the traits are very essential in chamomile breeding programs. Determination of the best indirect selection criteria for genetic improvement of essence percent and dry flower yield of German chamomile (Matricaria chamomilla L.) populations...

This paper describes an experiment examining how people compare two alternative categories and decide whether a given item would be better placed in one category or the other. The experiment asks whether an item's comparative classification in one of two alternative categories is related to the difference between the item's typicality as a member of those two categories. The alternative categor...

Background & Aims: The H9N2 avian influenza subtype is endemic in many parts of Iran and has the ability to transmit from bird to human. In the present study, the risk of this subtype for humans was assessed by determination of the viral titer and shedding time in bird. Method: The experiment was done on fifteen male budgerigars at 4 months of age. The birds w...

Background & Aims: The H9N2 avian influenza subtype is endemic in many parts of Iran and has the ability to transmit from bird to human. In the present study, the risk of this subtype for humans was assessed by determination of the viral titer and shedding time in bird. Method: The experiment was done on fifteen male budgerigars at 4 months of age. The birds were inoculated intranasally with al...

Phenology—the timing of seasonal events such as flower production, insect emergence, bird migrations, and snowmelt—has profound significance for people ecosystems. Many US national parks monitor phenology through citizen science projects that use tools developed by the USA National Phenology Network. We summarize scope efforts conducted over past decade identify some preliminary lessons recomme...

in order to investigate the effects of soil texture and density on corm and flower yield of saffron (crocus sativus l.) an experiment was conducted as a factorial layout based on complete randomized block design with three replications at the faculty of agriculture, ferdowsi university of mashhad during two growing seasons of 2009-2010 and 2010-2011. treatment included 6 soil textures (clay loa...

in order to study the effect of water deficit stress and different nitrogen levels on flower yield, yield components and water use efficiency of calendula officinalis l., an experiment was conducted as split plot based on randomized complete block design with three replications, at research field of islamic azad university, birjand branch in 2009. in this experiment, irrigation treatments (irri...