The old REH theory remains unsatisfactory and the new REH theory is problematical - a reply to holmquist and jukes

Summary In response to criticism of REH theory (Fitch 1980), Holmquist and Jukes (1981) have mostly avoided the criticism or misunderstood it. Since they themselves state in their response that Amino acid sequence data alone cannot be used to estimate total nucleotide substitutions, they agree with the criticism. Most of their paper treats the newer theory (here designated as the REHN theory) which attempts to use the nucleotide sequences encoding proteins to better estimate total nucleotide substitutions (Holmquist and Pearl 1980). Since I made no criticism of REHN theory, their comments are frequently beside the point of my original criticism of REH theory. Nevertheless, it is shown here that REHN theory is also unsatisfactory in that: One, the varions are now more clearly defined but in such a way as to preclude the same codon from suffering a nucleotide substitution in more than one evolutionary interval. Two, the set of codons that accepts silent substitutions is identical to the set that accepts amino acid changing nucleotide substitutions. Three, the uncertainty in the REH estimate is considerable in that alternative excellent fits to the same observatuonal data may give alternative REH values that differ significantly even before stochastic variation and selective bias are considered. Four, the fit of their model to data is an irrelevancy where there are zero degrees of freedom.     

External and internal factors regulating metabolic rates of an estuarine benthic community

Summary The structure and metabolism of a soft-sediment estuarine macrofaunal community were measured over an annual cycle at two depth-contours in mesohaline Chesapeake Bay. Additional data for plankton productivity and respiration, as well as seston and sediment organics are also summarized for these communities. Benthic community respiration ranged from 0.24–3.38 g O₂ m^-2 d^-1, and significant differences were detected between the two depths. Similarly, macroinfaunal standing stocks reached 11.2 and 32.3 g (ash free) m^-2 for 3 m and 6 m depth communities, respectively, and both exhibited mid-summer declines in abundance. Inferences drawn from these data facilitated a partitioning of benthic community respiration into macrofaunal and meiofaunal/microbial components with a residual term, much of which could be explained statistically by interactions between these two components. A multi-variate statistical model developed from these data matched benthic respiration measurements within 1–2 S.E. Mass-balances of organic carbon were estimated for water column and benthos at the two depthcontours for early and late summer, as well as for an entire, time-weighted year. These various analyses led to the tentative conclusions that this benthic community was regulated by such internal factors as macrofaunal/meiofaunal grazing and microbial gardening, and by external factors such as temperature and predation by nekton. However, it appears that the ultimate control for this community was the supply of energy from organic carbon.Contribution No. HPEL-1206, USASupported by grants with the Maryland Department of Natural Resources (PS-72-02(77-78)), J.A. Mihursky, Coordinating Principal Investigator     

Beobachtungen zum Bearbeiten von L?rchenzapfen (Larix decidua) in einer Schmiede des Buntspechts (Dendrocopos major)

Zusammenfassung Ein Buntspecht(Dendrocopos major) wurde beim Bearbeiten von Lärchenzapfen(Larix decidua) beobachtet; verschiedene Verhaltensweisen wurden gemessen. Die Bearbeitungsdauer ist bei trockener Witterung länger als bei nasser (Abb. 2). Während des Bearbeitens wird der Zapfen in regelmäßigen Zeitabständen gedreht (Abb. 3 unten); das heißt, daß mit zunehmender Bearbeitungsdauer die Häufigkeit des Drehens linear anwächst (Abb. 4). Für das Heranholen eines neuen Zapfens benötigt der Specht durchschnittlich 43 sec. Die Daten werden mit solchen vom Fichtenkreuzschnabel(Loxia curvirostra) verglichen.

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Observations on the Great Spotted Woodpecker(Dendrocopos major) when working on larch cones(Larix decidua) in a cleft

Summary Different activities of a Great Spotted Woodpecker working on larch cones forced into a cleft (Spechtschmiede) were measured. Dry cones are worked on longer than wet ones (Fig. 2). During the work the Woodpecker turns the cone at regular intervals of time (Fig. 3, below); i. e. the frequency of turning grows in a linear manner with increasing duration of the work on one cone (Fig. 4). To take a fresh cone, the Woodpecker takes generally 43 seconds. The results are compared with those obtained with the common crossbill(Loxia curvirostra).

     

Functional Overlay: An Illegitimate Diagnosis?

Functional overlay is not a recognized psychiatric diagnosis. Evaluating functional overlay and differentiating between this concept and organic conditions is important in medicolegal areas in which financial values are placed on pain and disability. Functional overlay is not malingering: the former is based on preconscious or unconscious mechanisms, the latter is consciously induced.In considering psychologic reactions to pain and disability, a gradient of simulation, malingering, symptom exaggeration, overvaluation, functional overlay and hysteria is useful. The dynamics of overlay are a combination of anxiety from body-image distortion and depression from decreased efficiency of the body, as well as the resulting psychosocial disruption in a patient''s life.     

The genusPicris (Asteraceae,Lactuceae) in Tropical Africa

Three species of the genusPicris L. are native in Tropical Africa:P. abyssinica Sch. Bip. (Ethiopia),P. xylopoda Lack, spec. nova (Nigeria, Ethiopia) andP. humilis DC. (Senegal, Mali). There are indications that the two perennial species,P. abyssinica andP. xylopoda, are related to and have evolved from a primitive Central Asiatic stock in a manner parallel to many African species ofCrepis L.P. humilis, on the other hand, is a small annual plant with a high number of derived characters. The introduced species of European origin growing south of the Sahara are briefly mentioned.     

Membrane surface properties of sheep erythrocytes,an immunological reagent,after different treatments as reflected by partition in two-polymer aqueous phases

Sheep erythrocytes (E) which, with or without certain treatments, are currently used as “immunological reagents” to detect cells with specific receptors (by rosette-formation) have been partitioned in two-polymer aqueousphase systems selected so as to reflect charge-associatedor lipid-related membrane surface properties. We have found that the partitioning behavior of E is not affected in these phases by reacting the cells with anti-E antibody (either IgG or IgM), forming EA. The additional binding of complement to the cell-antibody complex, forming EAC, results, however, in a marked decrease in the partition coefficient,K. Apparently both the charge-associated and hydrophobic properties reflected by partitioning remain accessible to the phase polymers when the cells are coated with antibody, but are not with the addition of complement. It is interesting that EA can still rosette with T-lymphocytes (14), a property of E, while the additional coating with complement results in EAC which does not appreciably do so (26). Neuraminidase or trypsin treatments of E, which yield Es having quite different rosetting properties with T-lymphocytes (14), cause increasedKs and unchangedKs, respectively, in phases reflecting lipid-related surface properties. Either treatment causes reducedKs of E in charged-phase systems. Neuraminidase treatment also results in a reduced electrophoretic mobility of E, while trypsin treatment is not detectable by cell electrophoresis (25). We are currently studying the possible usefulness of employing cell electrophoresis and cell partitioning in charged-phase systems jointly to obtain information on events occurring at the shear plane versus those occurring deeper in the membrane.