Embryogenesis, Histology, and Organology of the Ovary of Brevoortia patronus

One hundred ninety-one large scale menhaden, Brevoortia patronus, ranging in age from larvae to sexually mature females were used in this study. Collections were made in the littoral and shallow off shore waters of the Gulf of Mexico from Dauphin Island, Alabama, westward to West Bay, Louisiana, at intervals throughout a five year period. Using standard paraffin techniques a number of staining methods were employed. Cytological and histological accounts are presented of the tissue elements of the gonads beginning with inception in the larvae, sexual differentiation to the sexes, and the cyclic changes associated with oogenesis and spawning in the mature fish. The microscopic developments occurring during these periods are correlated with gross features of the organ, the ages of specimens, and with seasonal periods. An account of the morphology and physiology of atretic oocytes and ovulated follicles is presented. Using the ovarian components as an index, the time and duration of the spawning season is established as occurring from late October to February or early March with some variance due to environmental factors. From the study it is possible to postulate that this species exhibits intermittent total spawning in the Gulf

Embryogenesis, Histology, and Organology of the Ovary of Brevoortia patronus

One hundred ninety-one large scale menhaden, Brevoortia patronus, ranging in age from larvae to sexually mature females were used in this study. Collections were made in the littoral and shallow off shore waters of the Gulf of Mexico from Dauphin Island, Alabama, westward to West Bay, Louisiana, at intervals throughout a five year period. Using standard paraffin techniques a number of staining methods were employed. Cytological and histological accounts are presented of the tissue elements of the gonads beginning with inception in the larvae, sexual differentiation to the sexes, and the cyclic changes associated with oogenesis and spawning in the mature fish. The microscopic developments occurring during these periods are correlated with gross features of the organ, the ages of specimens, and with seasonal periods. An account of the morphology and physiology of atretic oocytes and ovulated follicles is presented. Using the ovarian components as an index, the time and duration of the spawning season is established as occurring from late October to February or early March with some variance due to environmental factors. From the study it is possible to postulate that this species exhibits intermittent total spawning in the Gulf

A Study of Nektonic and Benthic Faunas of the Shallow Gulf of Mexico Off the State of Mississippi As Related to Some Physical, Chemical, and Geological Factors

A seasonal study of the nektonic and benthic faunas of the shallow Gulf of Mexico off Mississippi was conducted from January 1967 through May 1969. It was planned to sample monthly six fixed offshore stations at depths ranging from 5 to 50 fathoms in the open Gulf. In general this was carried out fairly well. Water samples were taken from surface, midwater, and bottom levels each time a station was occupied, and temperatures and salinities were recorded for each of these. Samples were tested for the presence of nitrates, nitrites, ortho-phosphates and total phosphates. Secchi disc extinction points were recorded. Grab samples were taken for the determination of bottom composition. Plankton samples were taken from surface, midwater and bottom levels. Copepods, brachyuran zoea and megalops, stomatopod larvae, Lucifer faxoni, Acetes a. carolinae, Penilia avirostris, Doliolum sp. and fish eggs and larvae were present in greatest abundance. Surface and benthic nekton samples were obtained. Dredge samples were made quarterly and twelve invertebrate species and three species of fishes were collected. Renilla mülleri was the most abundant species taken, and the fish catch consisted of Centropristes ocyurus, Citharichthys spilopterus and Etropus crossotus. Accounts of 50 invertebrate species (24,679 specimens) and 129 fishes (93,563 specimens) taken in trawl hauls is presented. Temperature and salinity data are given for all species. Relative abundance, seasonal bathymetric distributions and movements, apparent growth patterns, catch per unit of effort and various biological data are noted for the most abundant species. Station 5 (40 fathoms) produced the largest percentage of trawl catches (22.7). Renilla mülleri was the most abundant invertebrate taken in trawling. The brown shrimp, Penaeus aztecus, was second in abundance (10.92%). The five most abundant species comprising 80.57% numerically of the catch were croaker, longspine porgy, butterfish, spot, and seatrout. The species comprising 91.89% of the catch by weight were the croaker, longspine porgy, spot, seatrout, lizardfish, butterfish, pinfish, bank sea bass, sea catfish and black fin sea robin. The families Sciaenidae, Sparidae and Stromateidae were represented by the greatest numbers and comprised 82.9% of the total catch. Families considered to be of commercial importance contributed 92.9% to the total fish catch

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Future oil possibilities of the Eastern Interior Basin

Cover title.Reprinted from Bulletin of the American Association of Petroleum Geologists, v. 35, no. 2, Feb. 1951

Judgments of risk frequencies : tests of possible cognitive mechanisms

How do people judge which of 2 risks claims more lives per year? The authors specified 4 candidate mechanisms and tested them against people's judgments in 3 risk environments. Two mechanisms, availability by recall and regressed frequency, conformed best to people's choices. The same mechanisms also accounted well for the mapping accuracy of estimates of absolute risk frequencies. Their nearly indistinguishable level of performance is remarkable given their different assumptions about the underlying cognitive processes and the fact that they give rise to different expectations regarding the accuracy of people's inferences. The authors discuss this seeming paradox, the lack of impact of financial incentives on judgmental accuracy, and the dominant interpretation of inaccurate inferences in terms of biased information processing