Sex ratios of Metapenaeus kutchensis George, George and Rao, 1963 and Parapenaeopsis sculptilis (Heller, 1862) in the Gulf of Kachchh, Western India

Sex ratio data of two species of penaeid prawns Metapenaues kutchensis George, George and Rao, 1963 and Parapenaeopsis sculptilis (Heller, 1862), occurring in the Gulf of Kachchh, were statistically analysed. A preponderance of females was observed in both the species and the ratio of male to female for both years combined for M. kutchensis and P. sculptilis was found to be 1:15 and 1:2.7, respectively. Chi-square analysis revealed significant difference in the sex ratio of the two species.

Influence of Water Depth on the Rate of Expansion of Giant Cutgrass Populations and Management Implications

Giant cutgrass ( Zizaniopsis miliacea (Michx.) Doell. & Asch.), a tall emergent grass native to the southeastern United States, was studied in Lake Seminole where it formed large expanding stands, and Lake Alice where it was confined to a stable narrow fringe.

Biscayne aquifer in Dade and Broward Counties, Florida

The Biscayne Aquifer is the principal source of water for the heavily populated area in the vicinity of West Palm Beach and Miami. The publication of this data is timely and will assist in the intelligent development of the water resources of the area.(PDF has 64 pages)

El tempe argentino

Marcos Sastre (1809-1887) fue un eminente educador y un destacado promotor de la cultura nacional además de un naturalista autodidacta. El Tempe Argentino, una de sus principales escritos, describe la flora, la fauna y la geografía del Delta del Paraná ilustrada con grabados de su autoría. Esta obra cuyo nombre evoca el Valle de Tempi, en la Tesalia griega fue publicada por primera vez en 1858 manteniendo su vigencia hasta mediados del siglo XX . En este número de la Serie Documentos presentamos la versión digitalizada de fragmentos - prólogo, introducción capítulo XVI, notas al apéndice y finales,semblanza de Marcos Sastre, bibliografía, reconocimientos, índice alfabético de la fauna y flora e índice completo-, de la obra publicada en 1938 por el Consejo Nacional de Educación . Esta edición gratuita fue corregida por el Dr. Emiliano Mac Donagh quién supervisó este libro incorporando notas e imágenes. En esta versión digital contamos con la invalorable y generosa ayuda del artista plástico Exequiel Martínez (http://www.exequielmartinez.com.ar/autor_a.htm) quién mejoró las figuras correspondientes a los peces, ya que, debido a la antigüedad de la edición y el proceso de digitalización, perdían definición. Esperamos, desde nuestro lugar, sumarnos a la divulgación que se viene realizando sobre este prohombre y contribuir con este modesto aporte, a recordar y difundir la obra de una de las figuras destacadas de la historia de la educación de la Argentina.

Changes in frost frequency and desert vegetation assemblages in Grand Canyon, Arizona

The effect of decreasing frost frequency on desert vegetation was documented in Grand Canyon by replication of historical photographs. Although views by numerous photographers of Grand Canyon have been examined, 400 Robert Brewster Stanton and Franklin A. Nims views taken in the winter of 1889-1890 provide the best information on recent plant distribution. In Grand Canyon, where grazing is limited by the rugged topography, vegetation dynamics are controlled by climate and by demographic processes such as seed productivity, recruitment, longevity and mortality. The replicated photographs show distribution and abundance of several species were limited by severe frost before 1889. Two of these, brittlebush (Encelia farinosa) and barrel cactus (Ferocactus cylindraceus), have clearly expanded their ranges up-canyon and have increased their densities at sites where they were present in 1890. In 1890, brittlebush was present in warm microhabitats that provided refugia from frost damage. Views showing desert vegetation in 1923 indicate that Encelia expanded rapidly to near its current distribution between 1890 and 1923, whereas the expansion of Ferocactus occurred more slowly. The higher frequency of frost was probably related to an anomalous increase in winter storms between 1878 (and possibly 1862) and 1891 in the southwestern United States.