Toward a physiological explanation of juvenile growth curves

Juvenile growth curves are generally sigmoid in shape: Growth is initially nearly exponential, but it slows to near zero as the animal approaches maturity. The drop‐off in growth rate is puzzling because, everything else being equal, selection favors growing as fast as possible. Existing theory posits sublinear scaling of resource acquisition with juvenile body mass and linear scaling of the requirement for maintenance, so the difference, fuel for growth, decreases as the juvenile increases in size. Experimental evidence, however, suggests that maintenance metabolism increases sublinearly not linearly with size. Here, we develop a new theory consistent with the experimental evidence. Our theory is based on the plausible assumption that there is a trade‐off in the capacity of capillaries to supply growing and developed cells. As the proportion of non‐growing cells increases, they take up more macromolecules from the capillaries, leaving fewer to support growing cells. The predicted growth curves are realistic and similar to those of previous models (Bertalanffy, Gompertz, and Logistic) but have the advantage of being derived from a plausible physiological model. We hope that our focus on resource delivery in capillaries will encourage new experimental work to identify the detailed physiological basis of the trade‐off underlying juvenile growth curves

Total reaction cross sections for neutron-nucleus scattering

Neutron total reaction cross sections at 45, 50, 55, 60, 65, and 75 MeV from nuclei 12C, 28Si, 56Fe, 90Zr, and 208Pb have been measured and are compared with (microscopic) optical model predictions. The optical potentials were obtained in coordinate space by full folding effective nucleon-nucleon interactions with realistic nuclear ground state density matrices. Good to excellent agreement is found.Comment: 5 pages, 1 figure, RevTeX

Magnetic and Dyonic Black Holes in D=4 Gauged Supergravity

Magnetic and Dyonic solutions are constructed for the theory of abelian gauged N=2 gauged four dimensional supergravity coupled to vector multiplets. The solutions found preserve 1/4 of the supersymmetry.Comment: Latex, 14 page

Physical Damage to Sweet Corn Seed Caused by Mechanical Harvesting and Subsequent Processing

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1.5W diode-pumped monolithic planar waveguide laser

We describe a compact and efficient Nd:YAG waveguide laser pumped by a diode-bar. An output of 1.5W is obtained for 6W incident power, with significant brightness enhancement

Polychromatic flow cytometry is more sensitive than microscopy in detecting small monoclonal plasma cell populations

Background There is an emerging role for flow cytometry (FC) in the assessment of small populations of plasma cells (PC). However, FC's utility has been questioned due to consistent underestimation of the percentage of PC compared to microscopy. Methods A retrospective study was performed on bone marrow samples analysed by 8-colour FC. Plasma cell populations were classified as polyclonal or monoclonal based on FC analysis. FC findings were compared with microscopy of aspirates, histology and immunohistochemistry of trephine biopsies, and immunofixation (IFX) of serum and/or urine. Results FC underestimated PC compared to aspirate and trephine microscopy. The 10% diagnostic cutoff for MM on aspirate microscopy corresponded to a 3.5% cutoff on FC. Abnormal plasma cell morphology by aspirate microscopy and clonality by FC correlated in 229 of 294 cases (78%). However, in 50 cases, FC demonstrated a monoclonal population but microscopy reported no abnormality. In 15 cases, abnormalities were reported by microscopy but not by FC. Clonality assessment by trephine microscopy and FC agreed in 251/280 cases (90%), but all 29 discordant cases were monoclonal by FC and not monoclonal by microscopy. These cases had fewer PC and proportionally more polyclonal PC, and when IFX detected a paraprotein, it had the same light chain as in the PC determined by FC. Conclusions FC was more sensitive in detecting monoclonal populations that were small or accompanied by polyclonal PC. This study supports the inclusion of FC in the evaluation of PC, especially in the assessment of small population

ATTENUATION OF GROUND REACTION FORCES IN DISMOUNTS FROM TEH BALANCE BEAM

Epidemiological studies have documented the incidence of injuries in female gymnasts . In comparison to other sports, the incidence of injury in gymnastics is high relative to other sports. One epidemiology study prompted the author to state that "...women's gymnastics should he recognized as a hazardous sport." To understand the etiology 01 injury, researchers have identified injuries by sites, types and/or events (floor, uneven bars, vault, and balance beam). Dismounts, considered an element 01 all events, have drawn attention as an injury mechanism. Studies have shown he dismount, especially when gymnasts attempt to "stick" their lauding, to be a major component of the incidence of injury. This study investigated ground reaction forces in the dismount from the balance beam under two styles (stick and roll-out of the landing). Attenuation of relatively high impact forces through modification of landing may be used, at minimum, in practices to reduce the exposure to gymnasts to this physical contraindication. Subjects were 23 female gymnasts who ranged in age (118 to 201 months, mean=158.8, SD=23.7) and level (5 to 10). Each subject was asked to perform two types of dismounts (roundoff and barani) from a balance beam and to land each dismount with two the different styles onto a mot adhered to a force platform. AU subjects had ground reaction forces for both styles of the roundoff. and 14 subjects had ground reaction forces for both styles of the barani dismount. Table 1 contains a summary of the ground reaction forces as a percentage of body weight. Our results indicate that vertical ground reaction forces are significantly reduced by rolling out of the landing

Anti-de Sitter/CFT Correspondence in Three-Dimensional Supergravity

Anti-de Sitter supergravity models are considered in three dimensions. Precise asymptotic conditions involving a chiral projection are given on the Rarita-Schwinger fields. Together with the known boundary conditions on the bosonic fields, these ensure that the asymptotic symmetry algebra is the superconformal algebra. The classical central charge is computed and found to be equal to the one of pure gravity. It is also indicated that the asymptotic degrees of freedom are described by 2D "induced supergravity" and that the boundary conditions "transmute" the non-vanishing components of the WZW supercurrent into the supercharges.Comment: Additional remarks in the extended case, added references, and small misprints corrected. To appear in Phys. Rev. D. Latex, 19 pages, no figure

Effective interaction for pf-shell nuclei

An effective interaction is derived for use in the full pf basis. Starting from a realistic G-matrix interaction, 195 two-body matrix elements and 4 single-particle energies are determined by fitting to 699 energy data in the mass range 47 to 66. The derived interaction successfully describes various structures of pf-shell nuclei. As examples, systematics of the energies of the first 2+ states in the Ca, Ti, Cr, Fe, and Ni isotope chains and energy levels of 56,57,58Ni are presented. The appearance of a new magic number 34 is seen.Comment: 5 pages, 4 figures, to be published in Phys. Rev.