Studies on tube restraint-induced attack on a metal target by laboratory mice

This study examines factors influencing the attack on a metal target by laboratory ‘TO’ strain mice confined within a narrow perspex tube and contrasts this form of behaviour with attack seen in less equivocal forms of ‘aggression test’. The effects of sex, housing condition, reproductive experience, density, anosmia and castration (in the male) were systematically examined. This ‘model’ of ‘aggression’ shows few parallels with social conflict, parental defense and electroshock-induced forms of attack as none of the above manipulations influenced the level of target biting in this situation. Thus, in spite of claims that tube restraint-induced attack may show parallels with intermale aggression, the data suggest that it involves a totally different motivation.     

The vasoactive intestinal peptide (VIP): VI. The 17-norleucine analog of the sequence 14–28

A pentadecapeptide amide with the C-terminal sequence (14–28) of the vasoactive intestinal peptide (VIP), but with the methionine residue in position 17 replaced by l-norleucine, was synthesized. The synthesis was carried out through stepwise chain lengthening, by the in situ technique. The norleucine-containing pentadecapeptide, l-arginyl-l-lysyl-l-glutaminyl-l-norleucyl-l-alanyl-l-valyl-l-lysyl-l-lysyl-l-tyrosyl- l-leucyl-l-asparaginyl-l-seryl-l-isoleucyl-l-leucyl-l-asparaginamide, was as active in relaxing different smooth-muscle preparations as the methionine-containing parent sequence.     

Les Corycaeidae (copepoda, cyclopoidea) des eaux libanaises: observations faunistiques et ecologiques

Based on WP2 plankton net samples collected monthly between1970 and 1982 at several inshore and offshore stations alongthe coast of Lebanon, a morphological and ecological study ofthe Corycaeidae was carried out. This family is representedby 11 species. These are as follows, in decreasing abundance:Farranula rostrata, Corycaeus brehmi, C. typicus, C. giesbrechti,C. ovalis, C. minimus, C. clausi, C. larus, C. flaccus, C. limbatusand C. furcifer. Corycaeus minimus indicus is recorded for thefirst time in the Mediterranean. The seasonal variations inabundance showed a maximum in spring (March-June), the timingof the peak being slightly different between the stations andaccording to the dominating species. Spatial distribution showedan eupelagic sub-superficial tendency for the majority of thespecies found. As far as the geographical distribution is concerned,the Corycaeidae of Lebanon belong, in general, to the Mediterraneanand temperate Atlantic planktonic fauna, with a certain subtropicalaffinity for some species, due to the effect of Indo-Pacificmigration through the Suez Canal to the Eastern MediterraneanBasin: C. minimus indicus is such a case.     

Lag‐phases in alien plant invasions: separating the facts from the artefacts

Temporal trends in biological invasions are often described by a lag‐phase of little or no increase in species occurrence followed by an increase‐phase in which species occurrence rises rapidly. While several biological and environmental mechanisms may underlie lag‐phases, they may also represent statistical artefacts or temporal changes in sampling effort. To date, distinguishing the facts from these artefacts has not been possible. Here we describe a method for estimating the lag‐phase in cumulative records of species occurrence, using a piecewise regression model that explicitly differentiates the lag and increase phases. We used the von Bertalanffy, logistic, linear and exponential functions to model the increase phase, and identified the best‐fitting function using model selection techniques. We confirmed the accuracy of our method using simulated data and then estimated the length of the lag‐phase (t_lag), the maximum collection rate (r) and the projected asymptotic number of records (K) using herbarium records for 105 weed species in New Zealand, while accounting for changes in sampling effort. Nearly all the New Zealand weed species had a lag‐phase, which averaged around 20–30 years, with 4% of species having a lag‐phase greater than 40 years. In more than two thirds of the cases, the accumulation of records was best modelled with the decelerating von Bertalanffy function, despite the tendency for temporal variation in sampling effort to force cumulative herbarium records to follow the sigmoidal shape of a logistic curve. A positive correlation between r and K is consistent with the assumption that the final distribution of an alien plant species reflects its rate of spread. Seemingly rare but fast‐spreading aliens may thus become tomorrow's noxious weeds. A positive correlation between inflection year and r warns that the weeds that have only begun to spread relatively recently may spread faster than previously known invaders.