The taste of polycose in hamsters

Hamsters show a preference for Polycose, a mixture of starch-derived glucose polymers, that is as strong as their preference for sucrose. However, in the hamster, taste aversions to Polycose may be less easily acquired than taste aversions to sucrose and the qualitative aspects of Polycose are unknown in this species. In order to examine the taste of Polycose in the hamster, we utilized a taste-aversion protocol with two conditioning trials. Animals were trained to avoid one of three different conditioning stimuli: 50 mM sucrose, 100 mM Polycose and a mixture of 50 mM sucrose with 100 mM Polycose. Control animals were conditioned with deionized water. After the second conditioning trial, generalization testing began for the three conditioning stimuli plus 3 mM citric acid, 300 mM KCI and 30 mM NaCl. The results showed that aversions to Polycose, sucrose or the Polycose/sucrose mixture cross- generalized, demonstrating that Polycose and sucrose share a common taste percept in the hamster. None of the aversions generalized to NaCl, citric acid or KCI. In addition, comparisons among the patterns of taste generalizations indicated that the tastes of Polycose and sucrose also had distinct qualitative components. Finally, although the taste of 100 mM Polycose was more salient than the taste of 50 mM sucrose, the taste of sucrose could still be detected in a mixture with Polycose.      

Molecular phylogeny of the genus Tibicina (Hemiptera, Cicadidae): rapid radiation and acoustic behaviour

To estimate the potential contribution of ethological and ecological parameters to the mechanisms of species formation and species isolation in the Palearctic cicada genus Tibicina , we constructed a molecular phylogenetic hypothesis of extant Tibicina species. Seven mitochondrial genes and a fragment of a nuclear gene were sequenced (3046 bp). Mitochondrial genes included 547 informative sites but the nuclear gene was too conserved to be included in the analysis. The tree was characterized by a basal polytomy indicating that Tibicina species arose rapidly. Such rapid radiation might explain the low divergence in the acoustic communication observed between species. Parameters describing habitat selection and acoustic communication were mapped onto the tree. A shift in habitat selection accompanied by acoustic changes might have contributed to one speciation event. The stochastic distribution of the same acoustic characters on the other branches of the tree implies, however, that the subtle acoustic differences between species could be the result of previous speciation events and independent evolutionary histories, rather than having contributed themselves in the speciation and isolation processes.  © 2007 The Linnean Society of London, Biological Journal of the Linnean Society , 2007, 91 , 611–626.     

The relationship of aerobic capacity,anaerobic peak power and experience to performance in CrossFit exercise

CrossFit is becoming increasingly popular as a method to increase fitness and as a competitive sport in both the Unites States and Europe. However, little research on this mode of exercise has been performed to date. The purpose of the present investigation involving experienced CrossFit athletes and naïve healthy young men was to investigate the relationship of aerobic capacity and anaerobic power to performance in two representative CrossFit workouts: the first workout was 12 minutes in duration, and the second was based on the total time to complete the prescribed exercise. The participants were 32 healthy adult males, who were either naïve to CrossFit exercise or had competed in CrossFit competitions. Linear regression was undertaken to predict performance on the first workout (time) with age, group (naïve or CrossFit athlete), VO₂max and anaerobic power, which were all significant predictors (p < 0.05) in the model. The second workout (repetitions), when examined similarly using regression, only resulted in CrossFit experience as a significant predictor (p < 0.05). The results of the study suggest that a history of participation in CrossFit competition is a key component of performance in CrossFit workouts which are representative of those performed in CrossFit, and that, in at least one these workouts, aerobic capacity and anaerobic power are associated with success.     

Two new species of Agatea (Violaceae) endemic to New Caledonia, with some taxonomic notes and a key to New Caledonian species

While working on a treatment of Violaceae for the Flore de Nouvelle-Caledonie et dependences , two new species were recognized, Agatea veillonii Munzinger and A. lecointei Munzinger. These species are here described and illustrated. Some taxonomic notes and a regional identification key are provided.     

Theory and practice of combining coagulant fixation and microwave histoprocessing

The German, F. Blum, introduced formalin as a fixative in 1893. Formalin rapidly became popular for hardening and preserving gross human and animal specimens. As a result, microscopy for diagnostic pathology by combining paraffin embedding and formalin fixation was developed. Alcohol-based fixatives have coagulation of proteins as their main preservative effect. Because there is no cross-linking, immunostaining is not compromised, and DNA and RNA is not damaged. Ethyl alcohol was used by Dutch scientists of the 18th century, but was replaced by the cheaper formalin. Addition of low molecular weight polyethylene glycol (PEG) optimized the coagulant fixative, Kryofix. The polyethylene glycol prevents excessive hardening and enhances the speed of coagulation of proteins. Kryofix was used on a large scale for skin biopsies in Leiden between 1987 and 2001. DNA preservation by the formulated coagulant fixative, BoonFix, is related to the concentration of ethyl alcohol, PEG and acetic acid. BoonFix has been used since 2004 in Leiden for over 40,000 diagnostic skin biopsies and more than 100,000 cervical samples. A literature review and three decades of experience with coagulant, formalin-free fixatives in pathology suggest that when health authorities realize that formalin invalidates expensive tests, it might eventually be eliminated legislatively from diagnostic pathology. Finally, coagulant fixation is optimal for microwave histoprocessing where ethyl alcohol is followed by isopropanol.     

The use of mitochondrial and nuclear sequence data in assessing the taxonomic status of the endangered Uluguru Bush Shrike Malaconotus alius

The endangered Uluguru Bush Shrike Malaconotus alius is a large, black-headed bush shrike, strictly endemic to the Uluguru Mountains in Tanzania. It has recently been suggested that this species has been misplaced within the genus Malaconotus and might instead be related to Malagasy Vangidae. To assess its systematic affinities, we analysed 1518 bp of sequence data obtained from a nuclear intron (myoglobin intron-2) and a mitochondrial protein-coding gene (ND2) using parsimony, maximum likelihood and Bayesian inference. Both genes strongly support the traditional placement within the genus Malaconotus , suggesting that similarities between the Uluguru Bush Shrike and the Vangidae are due to convergence. These results caution that taxonomic changes should not be made without a proper character analysis (i.e. assignment of character homology).     

Indirect cues in selecting a hunting site in a sit‐and‐wait predator

Sit‐and‐wait predators use relatively simple rules for their decisions to choose and leave a patch, such as using the direct presence of prey to select a hunting site. However, the direct presence of prey can only be used when there is a highly visited patch in the proximity of the predator. Therefore, it is plausible that sit‐and‐wait predators also exploit indirect cues of prey presence and, consequently, use associative learning to select a hunting site. The present study tests for the role of associative learning in a sit‐and‐wait predator species for which the ecology is well understood: Misumena vatia Clerck crab spiders. An ecologically relevant scenario is used by selecting flower colour as the conditioned stimulus and prey presence as the unconditioned stimulus. The results provide no evidence that M. vatia crab spiders use the association between flower colour and food presence for selecting a hunting site. After a training phase of being exposed to a colourful artificial flower highly visited by bees, spiders select a hunting site independently of its colour during the testing phase. Investigations of similar scope and ecological relevance are required with other sit‐and‐wait predators to identify the conditions promoting the use of associative learning for foraging site selection when animals face an unpredictable food supply.     

PANEL PERFORMANCE AND NUMBER OF EVALUATIONS IN A DESCRIPTIVE SENSORY STUDY

The assessor performance is a key point in a sensory evaluation. In particular, at the end of a session, a decrease of the performance can be feared. We propose to analyze this performance with various criteria: usual ones as the main product effect or the error variance; a new one measuring the perceived products variability. The performance can then be studied all along the session from two points of view: in taking into account the only products tested at a given instant (named instantaneous); in taking into account all the products tested up to a given instant (named cumulative). In the presented example, in spite of the large number of products successively tested by each assessor, the instantaneous performance of the panel shows no significant deterioration. Furthermore, when the number of products tested by each assessor increases, more significant product effects can be obtained thanks to the accumulation of the amount of data. This shows that the number of products that can be reasonably studied by one assessor during one session is generally underestimated.     

中国木薯乙醇的资源潜力及其空间分布

利用气候、土壤、地形和土壤等数据,运用ArcGIS的空间叠加分析功能,分析了中国木薯乙醇的分布生产潜力及空间分布.结果表明:中国适宜木薯分布的区域主要在广西、广东、福建、云南、江西和海南等广大南部地区,这些地区的木薯乙醇生产潜力也最高;适宜木薯种植的未利用地面积较少,仅有1.53×104hm2,其乙醇生产潜力仅能满足目前中国E10汽油约1.0%的乙醇需求量;要满足中国目前E10汽油的全部乙醇需求,需要扩大目前木薯总种植耕地面积的4.4～5.7倍,而中国的粮食安全需求则限制了该目标的实现;中国木薯乙醇满足未来生物乙醇的需求前景不容乐观,中国木薯乙醇企业的发展规划要充分考虑原料的可获性,切不可盲目扩大生产.