The ORSER System for the Analysis of Remotely Sensed Digital Data

The main effort of the University of Pennsylvania's Office for Remote Sensing of Earth Resources (ORSER) is the processing, analysis, and interpretation of multispectral data, most often supplied by NASA in the form of imagery and digital data. The facilities used for data reduction and image enhancement are described as well as the development of algorithms for producing a computer map showing various environmental and land use characteristics of data points in the analyzed scenes. The application of an (ORSER) capability for statewide monitoring of gypsy moth defoliation is discussed

The Cassia fasciculata Complex (Leguminosae) in Texas

The genus Cassia is represented in Texas by 15 well-marked species. One of these, C. fasciculata, is a highly variable taxon composed of several intergrading infraspecific taxa. The following treatment is the result of several summers\u27 field work combined with distributional data and morphological study of herbarium material. In the present paper it has been necessary to make two new varietal combinations in C. fasciculata. Hence, in conformity with Article 17 of the International Code of Botanical Nomenclature (1952), it seems desirable to give a somewhat detailed account of the distributional and morphological evidence which leads the author to treat the C. fasciculata complex as indicated

[Note On Cassia Orcuttii]

CASSIA Orcuttii (Britton & Rose) Turner, comb. nov

A measurement of the transverse velocity of Q2237+0305

Determination of microlensing parameters in the gravitationally lensed quasar Q2237+0305 from the statistics of high magnification events will require monitoring for more than 100 years (Wambsganss, Paczynski & Schneider 1990). However we show that the effective transverse velocity of the lensing galaxy can be determined on a more realistic time-scale through consideration of the distribution of light-curve derivatives. The 10 years of existing monitoring data for Q2237+0305 are analysed. These data display strong evidence for microlensing that is not associated with a high magnification event. An upper limit of v < 500 km/sec is obtained for the galactic transverse velocity which is smaller than previously assumed values. The analysis suggests that the observed microlensing variation may be predominantly due to stellar proper motions. The statistical significance of the results obtained from our method will be increased by the addition of data points from current and future monitoring campaigns. However reduced photometric errors will be more valuable than an increased sampling rate.Comment: 16 pages, including 17 figures. Accepted for publication in M.N.R.A.

Vegetative Key To Texas Desmanthus (Leguminosae) and Similar Genera

There are several genera of Mimosoideae in Texas that resemble each other, especially when only the flowers are present. Probably the plants most frequently wrongly identified in the genus Desmanthus are Acacia hirta Nutt. and A. texensis T.&G. (A. cuspidata Sehl.), followed closely by the prostrate plants of Neptunia. Other similar Texas genera are Calliandra, Hoffmanseggia, Schrankia, and Mimosa strigillosa T.&G. The following vegetative key is designed as a quick aid to place species of this complex of plants in their proper places when flowers and/or fruit are absent

Interpretation of the OGLE Q2237+0305 microlensing light-curve

The four bright images of the gravitationally lensed quasar Q2237+0305 are being monitored from the ground (eg. OGLE collaboration, Apache Point Observatory) in the hope of observing a high magnification event (HME). Over the past three seasons (1997-1999) the OGLE collaboration has produced microlensing light-curves with unprecedented coverage. These demonstrate smooth, independent (therefore microlensing) variability between the images (Wozniak et al. 2000a,b; OGLE web page). We have retrospectively compared probability functions for high-magnification event parameters with several observed light-curve features. We conclude that the 1999 image C peak was due to the source having passed outside of a cusp rather than to a caustic crossing. In addition, we find that the image C light-curve shows evidence for a caustic crossing between the 1997 and 1998 observing seasons involving the appearance of new critical images. Our models predict that the next image C event is most likely to arrive 500 days following the 1999 peak, but with a large uncertainty (100-2000 days). Finally, given the image A light-curve derivative at the end of the 1999 observing season, our modelling suggests that a caustic crossing will occur between the 1999 and 2000 observing seasons, implying a minimum for the image A light-curve ~1-1.5 magnitudes fainter than the November 1999 level.Comment: 11 pages, 15 figures. Accepted for publication in M.N.R.A.

Texas Species Of Desmanthus (Legurminosae)

The Texas species of Desmanthus (nomen conservandum), as treated in the present paper, total nine, one of which has two varieties. Six of these are found almost exclusively within the state

[Note On Cassia Orcuttii]

CASSIA Orcuttii (Britton & Rose) Turner, comb. nov