Mixtures of picloram and 2,4,5-T for the control of blackberry (Rubus fruticosus L. agg.)

The effectiveness of‘Tordon 50-d’(5% a.i. picloram plus 20% a.i. 2,4-D both as the triisopropanolamine salts) and various mixtures of 2,4,5-T and picloram were tested for the control of blackberry (Rubus fruticosus L. agg.) in Victoria, Australia. A high correlation was obtained between the % reduction in live canes and the % kill of crowns 13 months after Rubus procerus P.J. Muell. thickets were sprayed with 2,4,5-T or‘Tordon 50-d'. Counting the number of live canes is, therefore, a convenient method of comparing the efficacy of these herbicides for the control of blackberry. ‘Tordon 50-d’was generally more effective than 2,4,5-T but stimulation of suckering from roots was recorded at one site when low rates of‘Tordon 50-d’were used. It was necessary to add high dose rates of‘Tordon 50-d’to 2,4,5-T before there were worthwhile improvements in weed control.‘Tordon 5–20’(5% a.i. picloram as triisopropanolamine salt plus 20% 2,4,5-T as the ethyl hexyl ester) was only slightly more effective in controlling blackberry than‘Tordon 50-d'. The cost and soil residue problems associated with picloram should limit its use as an additive to 2,4,5-T for the control of blackberry in Australia.     

THE EFFECT OF RAINFALL ON THE LATE WOOD OF SCOTS PINE AND OTHER CONIFERS IN EAST ANGLIA

In Scots pine (Pinus silvestris L.) near Oxford, early woodwas found to start growing at about the beginning of April,late wood at about the beginning of July, and growth ceasesat about the end of August. Five late wood types were distinguishedin pine growing under the "continental" climatic conditionsof East Anglia. These types appear to be related to rainfalldistribution. The sharpness of the inner edge of the late wooddepends upon the availability of water at the end of early woodformation, a dry spell causing a sharp distinction. Wet conditionsin the middle of late wood formation may cause a zone of lessdense tissue, but this is rare.     

Use of Porcine Luteinizing Hormone at Oestrous Onset in a Protocol for Fixed‐Time Artificial Insemination in Gilts

The aim of this study was to evaluate the effect of porcine luteinizing hormone (pLH) given at oestrous onset in gilts, by different routes and doses, on the interval between onset of oestrus and ovulation (IOEO) and reproductive performance using a single fixed‐time artificial insemination (FTAI). A total of 153 gilts were submitted to oestrous detection at 8‐h intervals and assigned to three groups: control – without hormone application and inseminated at 0, 24 and 48 h after oestrous onset; VS2.5FTAI – 2.5 mg pLH by the vulvar submucosal route at oestrous onset and a single FTAI 16 h later; IM5FTAI – 5 mg pLH by the intramuscular route at oestrous onset and a single FTAI 16 h later. More VS2.5FTAI gilts (47.1%; p < 0.05) ovulated within 24 h after oestrous onset than control gilts (25.5%) whereas IM5FTAI gilts had an intermediate percentage (31.4%; p > 0.05). The IOEO tended to be shorter (p = 0.06) in VS2.5FTAI (30.2 ± 1.4 h) than in control (34.7 ± 1.4 h) gilts, but there was no difference (p > 0.05) between control and IM5FTAI (32.8 ± 1.4 h) gilts. Farrowing rate was not different (p > 0.05) among treatments. Total born piglets (TB) was lower (p < 0.05) in VS2.5FTAI (12.3 ± 0.4) than in control gilts (14.1 ± 0.4), whereas intermediate TB was observed in IM5FTAI gilts (13.3 ± 0.4). Due to the advancement of ovulation, reduction of the hormonal dose and the ease of application, the vulvar submucosal route would be the best option for FTAI protocols, but their negative impact on litter size remains to be elucidated. Taking into account the good fertility results obtained in IM5FTAI gilts whose ovulation was not advanced, the possibility of a single FTAI without any hormonal treatment should be further investigated, to establish reliable FTAI protocols for gilts.     

Climate Change During the Last Deglaciation in Antarctica

Greenland ice core records provide clear evidence of rapid changes in climate in a variety of climate indicators. In this work, rapid climate change events in the Northern and Southern hemispheres are compared on the basis of an examination of changes in atmospheric circulation developed from two ice cores. High-resolution glaciochemical series, covering the period 10,000 to 16,000 years ago, from a central Greenland ice core and a new site in east Antarctica display similar variability. These findings suggest that rapid climate change events occur more frequently in Antarctica than previously demonstrated.     

High-power directional emission from microlasers with chaotic resonators

High-power and highly directional semiconductor microcylinder lasers based on an optical resonator with deformed cross section are reported. In the favorable directions of the far-field, a power increase of up to three orders of magnitude over the conventional circularly symmetric lasers was obtained. A "bow-tie"-shaped resonance is responsible for the improved performance of the lasers in the higher range of deformations, in contrast to "whispering-gallery"-type modes of circular and weakly deformed lasers. This resonator design, although demonstrated here in midinfrared quantum-cascade lasers, should be applicable to any laser based on semiconductors or other high-refractive index materials.