Experimental tests of CPT symmetry and quantum mechanics at CPLEAR

We review a phenomenological parametrization of an open quantum-mechanical formalism for CPT violation in the neutral kaon system, and constrain the parameters using fits to recent CPLEAR data.We review a phenomenological parametrization of an open quantum-mechanical formalism for CPT violation in the neutral kaon system, and constrain the parameters using fits to recent CPLEAR data

Experimental tests of CPT symmetry and quantum mechanics at CPLEAR

We review a phenomenological parametrization of an open quantum-mechanical formalism for CPT violation in the neutral kaon system, and constrain the parameters using fits to recent CPLEAR data

Rats don't always respond faster for more food: the paradoxical incentive effect

Rats' leverpressing was reinforced on variable-ratio (VR) schedules. As ratio values increased, response rates initially increased with them, then eventually decreased. In Experiment 1, rates were uniformly higher with one-pellet reinforcers than with two-pellet reinforcers- the paradoxical incentive effect. Killeen's (1994) mathematical principles of reinforcement (MPR) described the data quantitatively but failed to predict the advantage for the one-pellet condition. In Experiment 2, rats received one-, two-, and three-pellet reinforcers with counterbalanced preloads of pellets; the continued superiority of the smaller reinforcers ruled out a satiation explanation. Experiment 3 introduced a 20-sec intertrial interval (ITI), and Experiment 4 filled the ITI with an alternate response to test a memorial/overshadowing explanation. In Experiment 5, the rats received one or two standard grain pellets or one sucrose pellet as reinforcers over an extended range of ratios. Once again, rates were higher for one than for two pellets at short to moderate VR values; thereafter, two pellets supported higher response rates. The diminution of the effect in Experiment 3 and its reversal in Experiment 4 and in Experiment 5 at large ratios provided evidence for overshadowing and reconciled the phenomenon with MPR

Pharmacokinetics of albendazole, albendazole sulfoxide and netobimin in goats

Peer reviewe

Resistência anti-helmíntica em rebanhos caprinos no Estado do Ceará Anthelmintic resistance in goat herds in the State of Ceará

Um levantamento em nível de campo sobre resistência anti-helmíntica em nematódeos gastrintestinais de caprinos foi realizado em 34 rebanhos no Estado do Ceará. Em cada rebanho foram separados 30 cabritos, de ambos os sexos, com idade variando de 1 a 6 meses, os quais foram individualmente pesados, identificados e distribuídos em três tratamentos: 1) Oxfendazole na dose de 4,75mg/kg; 2) Levamisole na dose de 7,5 mg/kg e 3) Controle (não medicado). Os anti-helmínticos foram administrados de acordo com o peso individual de cada animal e, a dosagem utilizada para cada produto foi a recomendada pelo laboratório fabricante. Foram colhidas fezes dos animais de todos os tratamentos, para OPG e coprocultura, no dia da medicação e 7 dias após. Dos 34 rebanhos avaliados, 7 (20,6%) apresentaram resistência aos imidazóis, 6 (17,6%) aos benzimidazóis e 12 (35,3%) revelaram resistência múltipla. Apenas em 9 rebanhos (26,5%), os nematódeos foram sensíveis aos anti-helmínticos avaliados. Através do questionário aplicado detectou-se que 52,9% dos caprinocultores entrevistados usavam anti-helmínticos de amplo espectro. Os resultados das coproculturas mostraram que os gêneros sobreviventes à medicação com oxfendazole foram principalmente Haemonchus sp, seguido em menor frequência por Oesophagostomum sp, enquanto que ao cloridrato de levamisole sobreviveram Haemonchus sp, Oesophagostomum sp e Trichostrongylus sp.<br>Goats of 45 farms in the State of Ceará, Brazil, were treated with anthelmintics for gastrointestinal nematodes, and their resistance to the anthelmintics was evaluated. On each farm 30 kids were weighed, ear-tagged and divided into three groups of ten. The first group received oxfendazole at 4.75mg/kg, the second levamisole at 7.5mg/kg, and the third group remained untreated as control. All goats were drenched according to their individual body weight. Fecal samples were collected from all animals (treated and control) on the day of treatment and 7 days later, to provide material for egg counts and larval cultures. Among 34 surveyed herds 20.6% showed levamisole resistance, 17.6% showed resistance to benzimidazole, and 35.3% had multiple resistance. At the time of the assessment 52.9% of the farmers were using broad spectrum anthelmintics. Only 26.5% of the surveyed herds had nematode populations susceptible to the anthelmintics assessed. The results of larval cultures showed that larvae surviving the treatment with oxfendazole were mainly Haemonchus sp and, to a lesser extent, Oesophagostomum sp; those surviving levamisole treatment were Haemonchus sp, Oesophagostomum sp and Trichostrongylus sp