Adaptations, exaptations, and spandrels.

Adaptation and natural selection are central concepts in the emerging science of evolutionary psychology. Natural selection is the only known causal process capable of producing complex functional organic mechanisms. These adaptations, along with their incidental by-products and a residue of noise, comprise all forms of life. Recently, S. J. Gould (1991) proposed that exaptations and spandrels may be more important than adaptations for evolutionary psychology. These refer to features that did not originally arise for their current use but rather were co-opted for new purposes. He suggested that many important phenomena—such as art, language, commerce, and war—although evolutionary in origin, are incidental spandrels of the large human brain. The authors outline the conceptual and evidentiary standards that apply to adaptations, exaptations, and spandrels and discuss the relative utility of these concepts for psychological science. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spatio-temporal analysis of nucleate pool boiling: identification of nucleation sites using non-orthogonal empirical functions

The analysis of spatio-temporal data and the physical understanding of the systems generating them are often limited by the available techniques. These limitations are especially evident in nucleate boiling. This paper investigates the analysis of a sequence of temperature fields obtained from a pool nucleate boiling experiment. Spatio-temporal data for the wall temperature in pool nucleate boiling of water on a thin, horizontal, stainless steel plate were obtained by liquid crystal thermography and high speed video recording. A previous analysis provided examples of the thermal conditions for activation of individual nucleation sites, for the heat transfer mechanisms during bubble growth and for the consequent interactions between adjacent sites. Principal component analysis (PCA) is shown to provide a reconstruction of the temperature fields that is accurate in the root mean square sense but which obscures information about the underlying physics, such as positions of the nucleation sites. In contrast, a new approach using non-orthogonal empirical functions (NEFs) encodes the relevant physical constraints (e.g., each NEF has a radially symmetrical form as suggested by the pattern of cooling during bubble growth). NEFs provide an efficient identification of the positions of active sites in successive frames; they are better suited to the analysis of non-stationary dynamics than PCA and allow for information compression.     

Creep behavior of the ternary 95.5Sn-3.9Ag-0.6Cu solder—Part I: As-cast condition

The compression creep behavior was studied for the ternary solder alloy 95.5Sn-3.9Ag-0.6Cu in the as-cast condition. Samples were tested under stresses of 2–45 MPa and temperatures of −25–160°C. There was a significant variability in the creep curve shape, strain magnitude, and steady-state strain-rate properties. A multivariable linear-regression analysis of the steady-state strain-rate data, using the sinh-law stress representation, indicated two mechanisms distinguished by low- and high-temperature regimes of −25–75°C and 75–160°C, respectively. The sinh-law stress exponent (n) and apparent-activation energy (ΔH) in the −25–75°C regime were 4.4 ± 0.7 kJ/mol and 25 ± 7 kJ/mol (63% confidence intervals), respectively. Those same parameters in the 75–160°C regime were 5.2±0.8 kJ/mol and 95±14 kJ/mol, respectively, for the high-temperature regime. The values of ΔH suggested a short-circuit diffusion mechanism at low temperatures and a lattice or bulk-diffusion mechanism at high temperatures. The stress dependency of the steady-state strain rate did not indicate a strong power-law breakdown behavior or a threshold stress phenomenon. Cracks and grain-boundary sliding were not observed in any of the samples. As the creep temperature increased, a coarsened particle boundary and particle depletion zone formed in the region of fine Ag₃Sn particles that existed between the Sn-rich phase areas. The coarsened particle boundary, as well as accelerated coarsening of Ag₃Sn particles, were direct consequences of the creep deformation process.     

Changes in bone mass and bone biomarkers of cynomolgus monkeys during pregnancy and lactation

A substantial amount of calcium is transferred from the mother to the fetus and infant during pregnancy and lactation. Involvement of the skeleton in meeting this demand should be reflected in changes in bone mass and turnover. The purpose of the study was to determine the effects of pregnancy, lactation, and recovery on the skeleton in 43 young (prepeak bone mass) female monkeys. Whole body (WBBMC) and lumbar vertebrae 2-4 bone mineral content were determined by dual x-ray absorptiometry at baseline and 1, 4, and 10 months postpartum. Alkaline phosphatase, bone Gla protein, and urinary crosslinks were measured at baseline, during the third trimester, and 1, 4, and 10 months postpartum. Compared to nonpregnant, nonlactating monkeys, pregnant monkeys had similar rates of bone mass gain (nonpregnant, nonlactating WBBMC, 25+/-9 mg/day; pregnant WBBMC, 20+/-14 mg/day). Compared to pregnant monkeys, lactating females had increased bone turnover, as indicated by elevated bone biomarker levels (lactating alkaline phosphatase, 259+/-20 IU/L) and decreased bone mass (lactating WBBMC, -99+/-21 mg/day). Densitometry showed that bone mass gain in the lactating monkeys did not compensate for lactational loss by 10 months postpartum (WBBMC, 6.95+/-9 mg/day). This lack of recovery may have been due to the fact that serum estrogen concentrations were just beginning to return to baseline at 10 months postpartum. In conclusion, the cynomolgus monkey skeleton responds similarly to that of women during pregnancy and lactation. Recovery from lactational bone loss is not complete by 10 months postpartum.     

Compression stress–strain and creep properties of the 52In–48Sn and 97In–3Ag low-temperature Pb-free solders

Lead (Pb)-free, low melting temperature solders are required for step-soldering processes used to assemble micro-electrical mechanical system (MEMS) and optoelectronic (OE) devices. Stress–strain and creep studies, which provide solder mechanical properties for unified creep-plasticity (UCP) predictive models, were performed on the Pb-free 97In–3Ag (wt.%) and 58In–42Sn solders and counterpart Pb-bearing 80In–15Pb–5Ag and 70In–15Sn–9.6Pb–5.4Cd alloys. Stress–strain tests were performed at 4.4 × 10^?5 s^?1 and 8.8 × 10^?4 s^?1. Stress–strain and creep tests were performed at ?25, 25, 75, and 100°C or 125°C. The samples were evaluated in the as-fabricated and post-annealed conditions. The In–Ag solder had yield stress values of 0.5–8.5 MPa. The values of ΔH for steady-state creep were 99 ± 14 kJ/mol and 46 ± 11 kJ/mol, indicating that bulk diffusion controlled creep in the as-fabricated samples (former) and fast-diffusion controlled creep in the annealed samples (latter). The In–Sn yield stresses were 1.0–22 MPa and were not dependent on an annealed condition. The steady-state creep ΔH values were 55 ± 11 kJ/mol and 48 ± 13 kJ/mol for the as-fabricated and annealed samples, respectively, indicating the fast-diffusion controlled creep for the two conditions. The UCP constitutive models were derived for the In–Ag solder in the as-fabricated and annealed conditions.     

Studies on the transfer of tocopherol between lipoproteins

The net transfer of labeled α-tocopherol from donor to acceptor lipoproteins at physiological concentrations was investigated. Labeled lipoproteins were isolated i) followingin vitro addition of [3,4-³H]all rac-α-tocopherol to plasma, or ii) from plasma obtained 12–16 h after ingestion by normal subjects of an oral dose (100 mg each) of 2R,4′R,8′R-α-[5,7-(C²H₃)₂]tocopheryl acetate and 2S,4′R′,R-α-[5-C²H₃]tocopheryl acetate. A constant amount (on a protein basis) of labeled lipoprotein was incubated with an increasing amount of unlabeled acceptor lipoprotein for 2 h at 37°C. No discrimination between stereoisomers of α-tocopherol was detected. Labeled VLDL and labeled LDL (very low and low density lipoproteins, respectively) tended to retain their labeled tocopherol. Labeled high density lipoproteins (HDL) readily transferred the labeled tocopherol to VLDL (>60% transferred), while the transfer to LDL was dependent upon the ratio of labeled HDL/LDL with a lower net transfer at higher ratios. This dependency of the distribution of tocopherol upon the ratio of HDL/LDL was also observedin vivo. The tocopherol/mg HDL protein was measured in 11 subjects with varying HDL levels. As the %HDL in the plasma increased from 14 to 50%, the tocopherol/HDL protein also increased (r²=0.37,P<0.05).     

Psychotherapy, rhetoric, and hermeneutics: Implications for practice and research.

In that psychotherapists seek to interpret and transform the meanings of patients' communications, psychotherapy resembles rhetoric and hermeneutics. This article identifies some of these resemblances and considers their implications for psychotherapy practice and research. (PsycINFO Database Record (c) 2010 APA, all rights reserved)