The highest rank attainable in the Army is the five-star General of the Army. Often called a "five-star general", the rank of General of the Army has historically been reserved for wartime use and is not currently active in the U.S. Army.
With the NZGS (2005) soil groups not being based on the Atterberg Limits, it is apparent that the plasticity chart cannot fulfil the same classification role that is does in the USCS. Not only can NZGS (2005) soil names such as Clayey SILT not be derived from the plasticity chart, there is no means by which USCS soil groups derived from it can be converted into NZGS (2005) equivalents.
A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.
Often new evidence suggests a close relationship between species previously thought not to be closely related and there are some examples of this phenomenon on the RELATIONSHIPS THAT ARE AND ARE NOT page. The opposite also happens, with the new evidence indicating that species previously thought to be closely related are not so close and this section will deal with an example, the Inkcap mushrooms. There are a number of mushroom-producing fungi in which the mushroom caps dissolve into a black, inky mess. Over time, perhaps hours, perhaps days (depending on species and weather conditions) the cap of such a species disappears, starting from the outer edge, until only a small central portion is left atop the stem. Probably the best known of these is the Shaggy Inkcap (Coprinus comatus). Shown here is a group of Shaggy Inkcaps, still all white, before the inkiness has set in. The photo to the right of this paragraph shows one with half the cap gone. You can see the black edge to the cap and on the left a couple of inky blobs hanging from the cap edge and soon to fall off. In this species inkiness is associated with spore dispersal and there is a section about spore release in Inkcap mushrooms on this page.
ASTM D2487-06.Standard Practice for Classification of Soils for Engineering Purposes (unified Soil Classification System)
While there is clearly a correlation between plasticity and liquid limit for clays, this is not the case for silts, which by definition display dilatant behaviour and therefore must have a generally limited degree of plasticity (Table 1). The literature typically describe silts as being dilatant yet USCS (ASTM D2487) defines elastic silts as having “no to slow” dilatancy, and both AS 1726 and BS 5930 allow for high plasticity silts. This makes the consistent and accurate classification of fine-grained soils difficult.
It is not clear from a reading of NZGS (2005) whether intermediate soil names represent a continuum between CLAY and SILT or whether they are subsets of them. For example, does a Clayey SILT first have to satisfy the dilatancy requirement of SILT before “Clayey” is added in recognition of some minor cohesive component, or can it be a term applied to a plastic clay-silt mixture in which silt is clearly dominant but dilatancy is not a characteristic? The former would likely plot below the A-Line whereas the latter would likely plot above it. As a “low plasticity Clayey SILT” (with no reference to dilatancy) is presented as an example classification in NZGS (2005), it would appear that the soils are considered to be a continuum.
Inorganic silts and very fine sands, rock flour, silty or clayey fine sands. Slight plasticity to non-plastic, slow to rapid dilatancy.
A common classification scheme for living organisms uses concepts such as species and genus (plural: genera) and in this scheme species is the basic unit. A genus typically contains a number of species and species is said to be of lower taxonomic rank than genus. Other examples of taxonomic rank in this classification scheme are family, order, class, phylum and kingdom - with each of higher rank than the one to its left (and family is of higher rank than genus). Hence there are fewer genera than there are species, fewer families than there are genera and so on. It is clear that this is a hierarchical scheme and any hierarchical system of classification is an example of a taxonomic classification. Any particular species, genus, family and so on is an example of a taxon (plural: taxa) . Thus Amanita muscaria , Amanita xanthocephala , Gymnopilus norfolkensis and Hypholoma tuberosum are examples of taxa at species rank. Amanita, Gymnopilus and Hypholoma are examples of taxa at genus rank. Amanitaceae and Strophariaceae are examples of taxa at family rank. The family Strophariaceae includes a number of genera including Stropharia, Hypholoma and Gymnopilus.
New Zealand Geotechnical Society (2005). Field description of soil and rock. Guideline for the field classification and description of soil and rock for engineering purposes. New Zealand Geotechnical Society Inc.
The lower fines content threshold used in NZGS (2005) is an acknowledgment that some soils exhibit the fine-grained characteristics even though coarse-grained material is physically more abundant. This difference means that clayey or silty soils with a 50 to 65% sand content will be classified as coarse-grained according to the USCS, but fine-grained according to NZGS (2005). Casagrande (1948) would not have included such soils in the development of the plasticity chart.
Mosquitoes of this genus lay their eggs in rafts, like the Culex genus. Unlike Culex, when the eggs hatch, the larvae live underwater, breathing air through tubes they insert into the roots of aquatic plants, and don’t turn into adults until the following year.
Figure 3: Plasticity chart showing the distribution of the different soil groups as defined by NZGS (2005)
Culex tarsalis spreads encephalitis to people and horses west of the Mississippi, and occasionally is found in the east too. The larvae can live in irrigation puddles, ditches, ponds, drinking troughs or open cesspools. The adults bite at night, preferring birds but also biting livestock and humans. They hide in sheltered areas during the day and, like most Culex mosquitoes, survive the winter by hibernating.
Inkiness is both a very striking visual feature and one that is rare in fungi. Therefore it is not surprising that inkiness was taken to be an indicator of a close relationship and in earlier times the great majority of the species that dissolved were considered to belong to the genus Coprinus. Over time the genus Coprinus grew to include over 150 species, some with the inkiness slight to non-existent. However late in the 1900s the initial DNA studies indicated that the species in Coprinus were not related closely enough for all to be placed in the one genus - in fact, not even in the one family. This was also the conclusion even if only the definitely inking species of Coprinus were considered. For example, on the basis of the molecular evidence, Coprinus comatus was more closely related to some other, non-inking genera, than it was to many other inking species of Coprinus. These DNA findings were controversial and a number of mycologists thought the implications nonsensical, being contrary to long-held ideas . What do you do when you get new evidence that contradicts existing concepts? Obviously, re-check the methods to see if there have been any mistakes. If not, you can either accept one lot of evidence as more reliable than the other or leave the issue unresolved. Not necessarily a very happy result, but sometimes it's necessary to put a problem aside and wait for future developments to resolve the issue. In the case of Coprinus, there was further DNA analysis, using improved techniques and with analyses of larger segments of Coprinus genomes, and the conclusions were much the same. One thing to note is that the DNA evidence didn't come as a surprise to some mycologists, since there had been debate (for over a hundred years) about the correct relationships between the Coprinus species. Long before DNA analyses became possible a number of mycologists had pointed out that, based on various microscopic features, Coprinus was a mixed bag.
A routine part of any geotechnical investigation is the classification of the recovered soils. In New Zealand this should be undertaken in the field in accordance with the New Zealand Geotechnical Society’s guidelines. There is a general expectation that laboratory-based methods should both verify and enhance those classifications obtained in the field, yet it is not uncommon for the two to differ significantly. Field and laboratory data for fine-grained inorganic soils from across Auckland have provided an insight into the nature, magnitude and likely origins of these differences. It is demonstrated that field logging and the plasticity chart commonly assign the same materials to different soil groups. This appears to originate from the majority of soils being fundamentally plastic in nature yet displaying physical properties noticeably different from that expected for a clay due to the significant non-clay fraction. Furthermore the plasticity chart cannot be used to classify soils in accordance with the New Zealand taxonomy. As a result intermediate soil classifications incompatible with the plasticity chart are typically assigned in the field. Recommendations are given with respect to developing a stand-alone New Zealand-specific classification system and the use of both field and laboratory data.
If it were desired that species' names reflect an evolutionary classification then species' names would need to change as ideas about evolutionary relationships changed and that is what happens. Today Amanita xanthocephala is one of many species in the genus Amanita and Mycena interrupta is one of many species in the genus Mycena. All those organisms with species names beginning with Amanita are considered to be evolutionarily closer to each other than any is to an organism that belongs to a species that has a name beginning with Mycena. Naturally another valid statement would be produced if the previous sentence were changed by swapping the words Amanita and Mycena. Had you been alive in 1860 you would not have seen those species' names in use but instead Agaricus xanthocephalus and Agaricus interruptus respectively. The change in names is a result of a better understanding of the evolutionary relationships amongst mushroom-forming fungi and a desire to give similar names to evolutionarily close species. Agaricus xanthocephalus is called a synonym of Amanita xanthocephala and Agaricus interruptus a synonym of Mycena interrupta .