Development of the vertebrate limb is an important paradigm for studying the regulation of growth and patterning in three dimensions, and both classical experiments and recent molecular approaches have provided significant insights into the mechanisms involved. These studies have revealed that growth and patterning along the three orthogonal axes (anteroposterior, dorsoventral, and proximodista...

The homeobox-containing genes GHox-7 and GHox-8 have been proposed to play fundamental roles in limb development. The expression of GHox-8, by the apical ridge cells, and GHox-7, in the subridge mesoderm, suggests the involvement of these two genes in limb outgrowth and proximo-distal pattern formation. A straightforward way to test this is to remove the apical ridge. Here we report the relatio...

Outgrowth of normal chick limb bud mesoderm is dependent on the presence of a specialized epithelium called the apical ectodermal ridge. This ectodermal ridge is induced by the mesoderm at about the time of limb bud formation. The limbless mutation in the chick affects apical ectodermal ridge formation in the limb buds of homozygotes. The initial formation of the limb bud appears to be unaffect...

Recent experiments, in which barriers were inserted between anterior and posterior tissues of the chick wing bud, resulted in deletion of structures anterior to the barrier (Summerbell, 1979). From these data it was concluded that blockage of morphogen from the polarizing zone by the barrier resulted in the observed failure of specification of anterior structures. We suggest an alternative inte...

finger patterns and ridge-counts in a random sample of iranian muslims consisting of 100 males and 100 females are described. the most common finger patterns found were loops, having a frequency of 54.4% u.l., 3.4% r.l. in males and 51.2% u.l. and 4.8% r.l in females. the frequencies of arches and whorls in both sexes were 4% and 38.5% respectively. bimanual and sex differences were indistinct....

A low cross-polarization slot array antenna in the narrow wall of ridge waveguide is presented. A non-angled slot which is created in the narrow wall of the ridge waveguide is considered to be used as radiating resonant slot. The normalized resistance and normalized reactance curves are presented for design purposes. A six element slot array waveguide antenna with ridges on its narrow wall is t...

Radiometric precision is difficult to maintain in orbital images due to several factors (atmospheric conditions, Earth-sun distance, detector calibration, illumination, and viewing angles). These unwanted effects must be removed for radiometric consistency among temporal images, leaving only land-leaving radiances, for optimum change detection. A variety of relative radiometric correction techn...

Anomalies persist in the foundations of ridge regression as set forth in Hoerl and Kennard (1970) and subsequently. Conventional ridge estimators and their properties do not follow on constraining lengths of solution vectors using LaGrange’s method, as claimed. Estimators so constrained have singular distributions; the proposed solutions are not necessarily minimizing; and heretofore undiscover...

The astronomical site parameters for the Magdalena Ridge Observatory (MRO) are being studied from numerous aspects including meteorological, environmental, seismic and sky quality (e.g. “seeing”, cloud cover). Results to date indicate that MRO is an excellent site for astronomical observing. Seeing measurements of less that 1 arc second in the optical are routinely obtained. Seismic conditions ...