3,651 research outputs found
C-terminal fusion of eGFP to the bradykinin B-2 receptor strongly affects down-regulation but not receptor internalization or signaling
A functional comparison was made between the wildtype bradykinin B, receptor (B(2)wt) and the chimera B(2)eGFP (enhanced green-fluorescent protein fused to the C-terminus of B(2)Wt), both stably expressed in HEK 293 cells. There was almost no difference in terms of ligand-inducible receptor phosphorylation and internalization, signal transduction (accumulation of inositol phosphates) or expression and affinity. However, stimulation for up to 8 h with 10 mu M bradykinin (BK) resulted in a strong decrease in surface receptors (by 60% within 5 h) in B(2)Wt, but not in B(2)eGFP. When the expression levels of both constructs where comparably reduced using a weaker promoter, long-term stimulation resulted in a reduction in surface receptors for B(2)wt(low) to less than 20% within 1 h, whereas the chimera B(2)eGFP(low) still displayed 50% binding activity after 2 h. A 1-h incubation in the absence of BK resulted in a recovery of 60% of the binding in B(2)wt(low) after 1-h stimulation with BK, but of only 20% after 7-h stimulation. In contrast, B(2)eGFP(low) levels were restored to more than 70%, even after 7-h stimulation. These data indicate that although the fusion of eGFP to B(2)wt does not affect its ligand-induced internalization, it strongly reduces the down-regulation, most likely by promoting receptor recycling over degradation
Rational Choice and the Relevance of Irrelevant Alternatives
This experimental study investigates the inuence of irrelevant or phantom al- ternatives on subjects' choices in sequential decision making. Using experimental data from 45 subjects, we found that irrelevant alternatives bear significant rele- vance for decision making. We observe that only 38% of our subjects make the same choice after two phantom alternatives, as compared with the same decision problem when analyzed from scratch. Even allowing for a natural error rate as high as 25%, we find that between 40% and 60% of our subjects are led astray by the presence of phantom alternatives. Testing then basic postulates of rational choice, we find moderate violations of contraction monotonicity and static preference consistency, and substantial viola- tions of dynamic preference consistency. Finally we find that subjects exhibiting rational choice behaviour are far less susceptible to dependence on irrelevant alternatives than subjects which violate rational choice behaviour. Rational choice behaviour is thus a good proxy for the independence of a subject's choices of irrelevant alternatives.
Testing Decision Rules for Multiattribute Decision Making
This paper investigates the existence of an editing phase and studies the com- pliance of subjects' behaviour with the most popular multiattribute decision rules. We observed that our data comply well with the existence of an editing phase, at least if we allow for a natural error rate of some 25%. We also found a satis- factory performance of certain groups of subjects for the conjunctive rule, for the elimination{by{aspects rule, for the majority rule, and for the maximin rule. Our data suggest, however, rejection of the prominence hypothesis and of the maximax rule. Thus, our experiment sheds light on the existence of an editing phase and on the use of various multiattribute decision rules.
Complexity of Equivalence and Learning for Multiplicity Tree Automata
We consider the complexity of equivalence and learning for multiplicity tree
automata, i.e., weighted tree automata over a field. We first show that the
equivalence problem is logspace equivalent to polynomial identity testing, the
complexity of which is a longstanding open problem. Secondly, we derive lower
bounds on the number of queries needed to learn multiplicity tree automata in
Angluin's exact learning model, over both arbitrary and fixed fields.
Habrard and Oncina (2006) give an exact learning algorithm for multiplicity
tree automata, in which the number of queries is proportional to the size of
the target automaton and the size of a largest counterexample, represented as a
tree, that is returned by the Teacher. However, the smallest
tree-counterexample may be exponential in the size of the target automaton.
Thus the above algorithm does not run in time polynomial in the size of the
target automaton, and has query complexity exponential in the lower bound.
Assuming a Teacher that returns minimal DAG representations of
counterexamples, we give a new exact learning algorithm whose query complexity
is quadratic in the target automaton size, almost matching the lower bound, and
improving the best previously-known algorithm by an exponential factor
Rational Choice and the Relevance of Irrelevant Alternatives
This experimental study investigates the inuence of irrelevant or phantom al- ternatives on subjects' choices in sequential decision making. Using experimental data from 45 subjects, we found that irrelevant alternatives bear significant rele- vance for decision making. We observe that only 38% of our subjects make the same choice after two phantom alternatives, as compared with the same decision problem when analyzed from scratch. Even allowing for a natural error rate as high as 25%, we find that between 40% and 60% of our subjects are led astray by the presence of phantom alternatives. Testing then basic postulates of rational choice, we find moderate violations of contraction monotonicity and static preference consistency, and substantial viola- tions of dynamic preference consistency. Finally we find that subjects exhibiting rational choice behaviour are far less susceptible to dependence on irrelevant alternatives than subjects which violate rational choice behaviour. Rational choice behaviour is thus a good proxy for the independence of a subject's choices of irrelevant alternatives.Independence of Irrelevant Alternatives;Phantom Alternatives;Sequential Decision Making;Rational Choice;Multiattribute Decision Making
On Functionality of Visibly Pushdown Transducers
Visibly pushdown transducers form a subclass of pushdown transducers that
(strictly) extends finite state transducers with a stack. Like visibly pushdown
automata, the input symbols determine the stack operations. In this paper, we
prove that functionality is decidable in PSpace for visibly pushdown
transducers. The proof is done via a pumping argument: if a word with two
outputs has a sufficiently large nesting depth, there exists a nested word with
two outputs whose nesting depth is strictly smaller. The proof uses technics of
word combinatorics. As a consequence of decidability of functionality, we also
show that equivalence of functional visibly pushdown transducers is
Exptime-Complete.Comment: 20 page
Perfil dos pescadores esportivos do Sul do Pantanal.
Relatam-se e discutem-se os resultados de um levantamento feito atraves de questionario oral a 493 pescadores esportivos durante a alta temporada de pesca de 1994 no sul do Pantanal. O questionario levantou informacoes socio-economicas, custos e historico das viagens, gastos durante as visitas, razoes da visita e outros aspectos da experiencia de lazer no Pantanal. As principais caracteristicas dos gastos dos pescadores esportivos foram analisadas atraves de tres modelos de regressao linear. Os resultados indicam que a pesca esportiva no sul do Pantanal e realizada por grupos de homens de meia-idade, casados e com educacao formal e situacao economica superior em relacao ao que e tipico no Brasil. Em media, os pescadores ja visitaram a regiao quatro vezes. Realizam viagens de 2.700km, permanecendo seis dias, gastando US$970.00 e capturando 25kg de peixes cada um, por viagem, em media. Em geral, quando maior o nivel de escolaridade, de sucesso na pescaria, de renda, meio de transporte aereo e maior a distancia do local de origem ao Pantanal, maiores os gastos preditos por viagem e por dia. O sucesso da pescaria esta mais altamente correlacionado com a idade e o nivel de escolaridade do pescador e, ao contrario do pensamento convencional, nao correlacionado com os gastos, experiencia anterior no local, ou uma paixao por pesca. Independente do sucesso na captura, cerca de 22% dos pescadores compraram peixes antes de retornar a sua regiao de origem. Os gastos diretos totais relacionados as visitas de principal razao para o pescador esportivo visitar o Pantanal sul e o ambiente natural unico e nao a pesca. Esta informacao tem relevancia para o desenvolvimento do turismo regional, para os esforcos de "marketing" e para os objetivos de administracao dos recursos naturais do Pantanal. Alem disso, aqueles motivados para visitar o Pantanal principalmente por turismo contemplativo (observar o ambiente natural e a vida selvagem), gastam significativamente mais nas viagens do que aqueles motivados primariamente pelo sucesso potencial da pescaria ou pelo lazer.bitstream/item/37574/1/CT24.pd
Quanto vale o Pantanal? A valoração ambiental aplicada ao bioma Pantanal.
As informações contidas nesta publicação buscam assegurar a efetividade de polÃticas que garantam a sustentabilidade do bioma e ao mesmo tempo assegurem que a tomada de decisões em projetos para seu desenvolvimento, sejam coerentes e racionais. Neste sentido, é necessário que os múltiplos usos e valores dessas áreas úmidas sejam reconhecidos e considerados, mais particularmente o seu valor econômico, já que as decisões de planejamento de uso da terra tradicionalmente se baseiam em considerações econômicas. Os autores mostram que as estimativas desses valores devem estar baseadas em técnicas adequadas, pois os métodos tradicionais não conseguem determinar os benefÃcios de muitas funções ambientais ou os custos de sua perda. Também reportam que por meio de tais técnicas, conhecidas como métodos de valoração ambiental, é possÃvel determinar o valor monetário dos bens e serviços ambientais em relação a outros bens e serviços da economia, e dessa forma, refletir seus valores sociais e não meramente seus valores de mercado. Este trabalho explica de forma simples os fundamentos da valoração econômica ambiental e seu papel na tomada de decisões sobre os usos do Pantanal e leva o leitor a pensar na valoração econômica de ecossistemas como mais um elemento a ser considerado quando se tomam decisões de uso de áreas úmidas.bitstream/CPAP-2010/57310/1/DOC105.pd
Lipid contaminants: Polypropylene apparatus and vacuum pumps
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141137/1/lipd0192.pd
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