Thrombolysis with tissue plasminogen activator in acute myocardial infarction: no additional benefit from immediate percutaneous coronary angioplasty

A randomised trial of 367 patients with acute myocardial infarction was performed to determine whether an invasive strategy combining thrombolysis with recombinant tissue-type plasminogen activator (rTPA), heparin, and acetylsalicylic acid, and immediate percutaneous transluminal coronary angioplasty (PTCA) would be superior to a noninvasive strategy with the same medical treatment but without immediate angiography and PTCA. Intravenous infusion of 100 mg rTPA was started within 5 h after onset of symptoms (median 156 min). Angiography was performed 6-165 min later in 180 out of 183 patients allocated to the invasive strategy; 184 patients were allocated to the non-invasive strategy. Immediate PTCA reduced the percentage stenosis of the infarc

Rotationally driven magnetic reconnection in Saturn's dayside

Magnetic reconnection is a key process that explosively accelerates charged particles, generating phenomena such as nebular flares, solar flares and stunning aurorae. In planetary magnetospheres, magnetic reconnection has often been identified on the dayside magnetopause and in the nightside magnetodisc, where thin-current-sheet conditions are conducive to reconnection. The dayside magnetodisc is usually considered thicker than the nightside due to the compression of solar wind, and is therefore not an ideal environment for reconnection. In contrast, a recent statistical study of magnetic flux circulation strongly suggests that magnetic reconnection must occur throughout Saturn’s dayside magnetosphere. Additionally, the source of energetic plasma can be present in the noon sector of giant planetary magnetospheres. However, so far, dayside magnetic reconnection has only been identified at the magnetopause. Here, we report direct evidence of near-noon reconnection within Saturn’s magnetodisc using measurements from the Cassini spacecraft. The measured energetic electrons and ions (ranging from tens to hundreds of keV) and the estimated energy flux of ~2.6 mW m–2 within the reconnection region are sufficient to power aurorae. We suggest that dayside magnetodisc reconnection can explain bursty phenomena in the dayside magnetospheres of giant planets, which can potentially advance our understanding of quasi-periodic injections of relativistic electrons6 and auroral pulsations

Reconnection acceleration in Saturn's dayside magnetodisc:a multicase study with Cassini

Recently, rotationally driven magnetic reconnection was firstly discovered in Saturn’s dayside magnetosphere (Guo et al. 2018). This newly confirmed process could potentially drive bursty phenomena at Saturn, i.e., pulsating energetic particles and auroral emissions. Using Cassini’s measurements of magnetic fields and charged particles, we investigate particle acceleration features during three magnetic reconnection events observed in Saturn’s dayside magnetodisc. The results suggest that the rotationally driven reconnection process plays a key role in producing energetic electrons (up to 100 keV) and ions (several hundreds of keV). In particular, we find that energetic oxygen ions are locally accelerated at all three reconnection sites. Isolated, multiple reconnection sites were recorded in succession during an interval lasting for much less than one Saturn rotation period. Moreover, a secondary magnetic island is reported for the first time at the dayside, collectively suggesting that the reconnection process is not steady and could be ‘drizzle-like’. This study demonstrates the fundamental importance of internally driven magnetic reconnection in accelerating particles in Saturn’s dayside magnetosphere, and likewise in the rapidly rotating Jovian magnetosphere and beyond

An analysis of a wheat yield depression caused by high sowing rate with reference to the pattern of grain set within the ear

Grain set in spikelets of ears was reduced in spring-sown wheat established at high sowing rate (500 viable seeds/m²) compared with wheat planted at normal rates (250 seeds/m²), the reduction being greatest in spikelets positioned near the base and near the apex of the ear. Regression analysis revealed a significant and positive relationship between final grain set and spikelet dry weight at the early boot stage. Poor grain set in wheat grown at supra-optimal seeding rates was attributed to a combination of reduced carbohydrate supply and water stress in the young developing ear

Development and yield components of high-yielding wheat crops

In a field experiment, 'Arawa' wheat outyielded 'Aotea' by 10% through the production of a higher grain yield per ear. Irrigation had no effect on grain yield because of plant uptake of subsoil moisture. Nitrogen increased grain yield by 19% mainly by increasing ear number. Sowing rate had no effect on yield. Mean yield for the experiment was 6.6 t/ha, the mean yield components being 600 ears/m², each composed of just over 17 spikelets containing 1.5 grains which weighed 43 mg. Arawa produced larger grain than Aotea; no other treatment influenced mean weight per grain, which was unrelated to flag-leaf-area duration. It is suggested that further yield increases will best be achieved by increasing grain number per unit area, probably by increasing grains per spikelet, the component most highly correlated with yield in this experiment

Effects of sowing rate, irrigation, and nitrogen on the components of yield of spring-sown semidwarf and standard New Zealand wheats

'Karamu', a Mexican semidwarf wheat, outyielded 'Aotea' and 'Arawa' by an average of 20% when spring sown because of better grain set per spikelet and by the formation of more spikelets per ear. Irrigation raised grain yields in all cultivars by increasing tiller survival. Sowing at twice conventional rates depressed grain yields in all cultivars by reducing grain set. Nitrogen fertilisation lowered grain yields of all cultivars by 7% in unirrigated plots by decreasing ear populations, apparently by intensifying water stress. Nitrogen applied at the same rate to irrigated plots increased ear populations and grain yields by 10%. Responses support the hypothesis that poor grain set in wheat in the field is caused by insufficient assimilate supply to the developing ear

Effects of irrigation and fertiliser on the yields of 'Arawa', 'Aotea', and 'Karamu' wheats

Grain yields of 'Aotea', 'Arawa', and 'Karamu' wheats were depressed by irrigation during early stages of reproductive development which reduced the number of grains per spikelet and slowed the rate of reproductive development. Nitrogen fertiliser increased the ear population at harvest but had little effect on the dry weight or leaf area of the tillers during the critical pre-anthesis stage or on the mean values of the components of yield of the ears. There were no interactions between fertiliser and irrigation treatments. 'Karamu', a Mexican semi-dwarf, was similar to the New Zealand-bred wheats except that it had slightly more spikelets per ear and grains per spikelet, but it had smaller grains. An antitranspirant applied to irrigated wheat had no effect on any of the components of grain or straw yield. Responses were interpreted on the basis that pre-anthesis assimilate levels were modified by agronomic treatments and affected grain set

Wheat yield as affected by sowing rate, irrigation, and time of white clover introduction

On a fertile, moisture-retentive Wakanui silt loam Aotea wheat sown at 100 kg/ha yielded 6650 kg/ha, considerably more than when sown at 50 or 150 kg/ha. Lower yields of wheat planted at the 50 kg/ha rate were caused largely by low ear numbers, and the 150 kg/ha sowing rate resulted in the formation of many small ears. Ear size is discussed in relation to physiological factors, including carbohydrate supply during early ear development. Wheat overdrilled with white clover in September or October outyielded wheat and clover sown together in June. Irrigation up to 2 weeks after anthesis increased grain yield, and continuing irrigation through to harvest gave a further small response. Yield responses to irrigation were largely attributable to tiller survival