The contribution of developmental constraints and selective forces to the determination of evolutionary patterns is an important and unsolved question. We test whether the long-term evolutionary stasis observed for pollen morphogenesis (microsporogenesis) in eudicots is due to developmental constraints or to selection on a morphological trait shaped by microsporogenesis: the equatorial aperture...

An ocean general circulation model (OGCM) of the tropical Atlantic is coupled to an advective atmospheric boundary layer model. This configuration is used to investigate the hypothesis that resolving tropical instability waves (TIWs) in OGCMs will remove the equatorial cold bias that is a feature common to coarse-resolution OGCMs. It is shown that current eddy parameterizations cannot capture t...

[1] Sea surface temperature (SST) for the central equatorial Indian Ocean, has been reconstructed over the last 137 kyr, from Mg/Ca of the planktonic foraminiferal species Globigerinoides ruber. According to our record the equatorial Indian Ocean SST was 2.1 C colder during the last glacial maximum as compared to present times. The data further shows that the surface equatorial Indian Ocean was...

[1] Interannual anomalies in vertical profiles of stratospheric ozone, in both equatorial and extratropical regions, have been shown to exhibit a strong seasonal persistence, namely, extended temporal autocorrelations during certain times of the calendar year. Here we investigate the relationship between this seasonal persistence of equatorial and extratropical ozone anomalies using the SAGE‐co...

[1] Horizontal neutral winds play an important role in lowlatitude ionospheric E and F-region dynamics. In particular, the zonal winds have strong effects on the local structure of the low-latitude ionospheric current system. Accurate wind specification is therefore essential for modeling these currents. In order to investigate the retrieval of eastward electric fields from satellite-derived eq...

  The effects of gentamicin, lithium and combination of these drugs on ultrastructural morphology of rat submandibular glands were studied. Daily intraperitoneal injection of 40 mg/kg of gentamicin which causes chronic salivary gland toxicity, led to a marked decrease in gland's dry weight and total protein concentration but did not affect DNA content. Electron micrograph (EM) of submandibular ...

In rapidly rotating planetary atmospheres that are heated from below, equatorial superrotation can occur through convective generation of equatorial Rossby waves. If the heating from below is sufficiently strong that convection penetrates into the upper troposphere, then the convection generates equatorial Rossby waves, which can induce the equatorward angular momentum transport necessary for s...

The tropical intraseasonal oscillation (ISO) exhibits pronounced seasonality. The boreal summer ISO is more complex than its winter counterpart due to the coexistence of equatorial eastward, off-equatorial westward, and northward propagating, low-frequency modes and their interactions. Based on observational evidence and results obtained from numerical experiments, a mechanism is proposed for t...

perforation of the wall of the reticulum by a sharp foreign body often produces peritonitis and can cause involvement of other organs.in cattle the disease is economically important because of severe loss of production and high mortality rate.the objective of this study was to determine the presence and kinds of foreign bodies in apperently healthy buffaloes which were slaughtered in ahvaz abba...