Academic literature on the topic 'Ribeye area. eng'

Much of the knowledge presented in the following chapters has been gained using molecular genetic techniques to analyze the structure, synthesis, regulation, and effects of hormones. This chapter provides an overview of some of the relevant techniques and associated concepts. To allow the reader to understand older experiments, we have tried to include techniques that are now of mainly historical interest as well as current concepts. Deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) consist of nucleotides . A nucleotide consists of a base , a sugar moiety (either deoxyribose or ribose), and a phosphate group. The sugars and phosphates alternate in the backbone of a nucleic acid strand. In general, there are four possible bases. In DNA, these are adenine ( A ), cytosine ( C ), guanine ( G ), and thymine ( T ). Adenine and guanine are purines , whereas cytosine and thymine are pyrimidines . The corresponding nucleotides are adenosine , cytidine , guanosine , and thymidine. In RNA, uracil (uridine) is substituted for thymine (thymidine). DNA is double stranded. Each strand has a direction because the deoxyribose molecules forming the backbone are asymmetrical, with the phosphate bonds linking each two sugar molecules going from the 3’ position of one to the 5’ position of the next. Thus, the 5’ position of a sugar molecule is free at one end (the 5’ end) of the strand, and the 3’ position is free at the other. The two strands of a DNA molecule run in opposite directions, so that the 5’ end of one strand is opposed to the 3’ end of the complementary strand. The DNA strands interact with each other through complementary (Watson-Crick) base pairing , in which A and T, or C and G, are paired through hydrogen bonds. Thus, the sequence of one DNA strand unambiguously determines the sequence of the complementary strand during DNA replication. The length of a DNA segment is typically given in bases or nucleotides (nt) or, if double stranded, base pairs (bp).

The sulfide minerals are a group of materials dominated by binary and ternary compounds of sulfur with iron, cobalt, nickel, copper, zinc, and lead. Other members of this group of naturally occurring crystalline materials incorporate a variety of cations (e.g., Mn2+, MO4 + , Ag+, Hg2+, Cr3 + , Sn4+, Pt4+) and several other anions (Se2-, Te2-, As2 - , Sb2-). The sulfides are not only the most important group of ore minerals, constituting the raw materials for most of the world’s supplies of nonferrous metals, but also are substances that exhibit a fascinating diversity in structural chemistry and in electrical, magnetic, and other physical properties (Ribbe, 1974; Vaughan and Craig, 1978). The sulfide minerals range in properties from materials that are diamagnetic insulators, forming virtually colorless crystals when pure (e.g., ZnS), to diamagnetic semiconductors (e.g., PbS), to semiconductors or metallic conductors exhibiting various forms of ordered magnetism (e.g., CuFeS2, Fe7S8, CoS2), and to metals exhibiting weak temperature-independent Pauli paramagnetism (e.g., Ni3S4, Co9S8). The diversity of sulfide properties indicates that the valence electrons in these materials can range from extensively delocalized as in metals, to localized on the atoms as in insulators. This has presented problems for those attempting to develop bonding models and has also led to certain misconceptions regarding the kinds of models that may be appropriate. Earlier attempts to develop qualitative bonding models for sulfide minerals have been reviewed by Vaughan and Craig (1978) and include applications of valence-bond theory (Pauling, 1970) and ligand-field theory (Nickel, 1968, 1970), zone theory (Freuh, 1954), and qualitative molecular- orbital/band models (Burns and Vaughan, 1970; Vaughan et al., 1971; Prewitt and Rajamani, 1974). At about the same time, band-structure calculations on some of the binary sulfides of importance in materials science were being performed by physicists, and certain of the data of mineralogical interest have been reviewed by Marfunin (1979). The mid- 1970s saw the first successful attempts to perform MO calculations on metal-sulfide mineral systems, and a substantial number of systems have since been studied (many having been reviewed by Vaughan and Tossell, 1983).

<strong><em>Abstract. </em><strong>Fishers have often complained that standard United Kingdom groundfish survey data do not adequately reflect the grounds targeted by commercial fishers, and hence, scientists tend to make overcautious estimates of fish abundance. Such criticisms are of particular importance if we are to make a creditable attempt to classify potential essential fish habitat (EFH) using existing data from groundfish surveys. Nevertheless, these data sets provide a powerful tool to examine temporal abundance of fish on a large spatial scale. Here, we report a questionnaire-type survey of fishers (2001–2002) that invited them to plot the location of grounds of key importance in the Irish Sea and to comment on key habitat features that might constitute EFH for Atlantic cod <em>Gadus morhua</em>, haddock <em>Melanogrammus aeglefinus</em>, and European whiting <em>Merlangius merlangus</em>. Plotted grounds were cross-checked using records of vessel sightings by fishery protection aircraft (1985–1999). A comparison of the areas of seabed highlighted by fishers and the observations made on groundfish surveys were broadly compatible for all three species of gadoids examined. Both methods indicated important grounds for cod and European whiting off northern Wales, the Ribble estuary, Solway Firth, north of Dublin, and Belfast Lough. The majority of vessel sightings by aircraft did not match the areas plotted by fishers. However, fishing restrictions, adverse weather conditions, and seasonal variation of fish stocks may have forced fishers to operate outside their favored areas on the (few) occasions that they had been recorded by aircraft. Fishers provided biological observations that were consistent among several independent sources (e.g., the occurrence of haddock over brittle star [ophiuroid] beds). We conclude that fishers’ knowledge is a useful supplement to existing data sets that can better focus more detailed EFH studies.