Alfred Russel Wallace and the road to natural selection, 1844-1858.

Conventional wisdom has had it that the naturalist Alfred Russel Wallace and his colleague Henry Walter Bates journeyed to the Amazon in 1848 with two intentions in mind: to collect natural history specimens, and to consider evidential materials that might reveal the causal basis of organic evolution. This understanding has been questioned recently by the historian John van Wyhe, who points out that with regard to the second matter, at least, there appears to be no evidence of a "smoking gun" variety proving it so. In the present essay the circumstances of Wallace's interest in the matter are reviewed, and van Wyhe is taken to task with alternate explanations for the facts he introduces in his argument.

Photochemical generation and kinetic studies of a putative porphyrin-ruthenium(V)-oxo species.

Photo-disproportionation of a bis-porphyrin-diruthenium(IV) μ-oxo dimer gave a porphyrin-ruthenium(III) species and a putative porphyrin-ruthenium(V)-oxo species that can be detected and studied in real time via laser flash photolysis methods. As determined by its spectral and kinetic behavior, the same oxo transient was also formed by photolysis of a porphyrin-ruthenium(III) N-oxide adduct. Second-order rate constants for reactions with several substrates at 22 °C were determined; representative values of rate constants were kox = 6.

Chlamydomonas reinhardtii strain CC-124 is highly sensitive to blue light in addition to green and red light in resetting its circadian clock, with the blue-light photoreceptor plant cryptochrome likely acting as negative modulator.

The unicellular green alga Chlamydomonas reinhardtii has long served as model organism for studies on the circadian clock. This clock is present in all eukaryotes and some prokaryotes allowing them to anticipate and take advantage of the daily oscillations in the environment. Although much is known about the circadian clock in C.

Broadband behavior rating scales as screeners for autism?

In order to start providing important early intervention services to preschoolers and toddlers with autism, those children first need to be identified. Despite the availability of specialized autism assessment instruments, there is a need for effective screeners at the early childhood level. Three broadband behavior rating scales were evaluated in this study to determine if any of the scales on the instruments could adequately distinguish between children with autism from other clinically referred children.

Estimating the distance separating fluorescent protein FRET pairs.

Förster resonance energy transfer (FRET) describes a physical phenomenon widely applied in biomedical research to estimate separations between biological molecules. Routinely, genetic engineering is used to incorporate spectral variants of the green fluorescent protein (GFPs), into cellular expressed proteins. The transfer efficiency or rate of energy transfer between donor and acceptor FPs is then assayed.

Comparison of N-acetylmethionine reactivity between oxaliplatin and an oxaliplatin derivative with chiral () amine nitrogen atoms.

We have synthesized an oxaliplatin derivative using N,N'-dimethyl-1,2-diaminocyclohexane (Medach) as the diamine ligand. The complex (S,R,R,S)-Pt(Medach)(oxalate), where S,R,R,S represents the chiralities at N,C,C,N, respectively, was prepared and characterized by H NMR spectroscopy, COSY, NOESY, and HMQC. Oxaliplatin reacts with N-acetylmethionine (N-AcMet) to form [Pt(dach)(N-AcMet-)] and [Pt(dach)(N-AcMet-)], with the former favored at higher molar ratios of N-AcMet.

Coronary heart disease prevalence and occupational structure in U.S. metropolitan areas: a multilevel analysis.

This research explored the link between coronary heart disease (CHD) prevalence and metropolitan-area level occupational structure among 137 metropolitan/micropolitan statistical areas (MMSA) in the United States. Using data from the 2006-2008 Behavioral Risk Factor Surveillance System and 2007 County Business Patterns, logistic mixed models were developed to estimate CHD prevalence between MMSAs controlling for individual-level socioeconomic characteristics and various types of occupational structure. Results showed that CHD prevalence was lower in MMSAs where their economy was dominated by 'tourism and resort' and 'the quaternary sector' and higher in MMSAs dominated by 'manufacturing', 'transportation and warehousing', and 'mining'.

Solid shape discrimination from vision and haptics: natural objects (Capsicum annuum) and Gibson's "feelies".

A set of three experiments evaluated 96 participants' ability to visually and haptically discriminate solid object shape. In the past, some researchers have found haptic shape discrimination to be substantially inferior to visual shape discrimination, while other researchers have found haptics and vision to be essentially equivalent. A primary goal of the present study was to understand these discrepant past findings and to determine the true capabilities of the haptic system.

Twins born over weekends: are they at risk for elevated infant mortality?

Objective: To assess the impact of the day of birth on twin mortality in a population sample.

Methods: We analyzed weekend versus weekday twin births from the United States national twin birth data for the periods 1989-2002. We computed adjusted hazard ratios (HR) and 95% confidence intervals (CI) to assess the association between infant mortality and weekday of birth using the Cox proportional hazards model.

"In space" or "as space"?: a new model.

In this analysis natural systems are posed to subsystemize in a manner facilitating both structured information/energy sharing and an entropy maximization process projecting a three-dimensional, spatial, outcome. Numerical simulations were first carried out to determine whether n × n input-output matrices could, once entropy-maximized, project a three-dimensional Euclidean metric. Only 4 × 4 matrices could; a small proportion passed the test.

Measuring local context as context-word probabilities.

Context enables readers to quickly recognize a related word but disturbs recognition of unrelated words. The relatedness of a final word to a sentence context has been estimated as the probability (cloze probability) that a participant will complete a sentence with a word. In four studies, I show that it is possible to estimate local context-word relatedness based on common language usage.

Transcriptomic analysis of the zebrafish inner ear points to growth hormone mediated regeneration following acoustic trauma.

Background: Unlike mammals, teleost fishes are capable of regenerating sensory inner ear hair cells that have been lost following acoustic or ototoxic trauma. Previous work indicated that immediately following sound exposure, zebrafish saccules exhibit significant hair cell loss that recovers to pre-treatment levels within 14 days. Following acoustic trauma in the zebrafish inner ear, we used microarray analysis to identify genes involved in inner ear repair following acoustic exposure.

Blindness enhances tactile acuity and haptic 3-D shape discrimination.

This study compared the sensory and perceptual abilities of the blind and sighted. The 32 participants were required to perform two tasks: tactile grating orientation discrimination (to determine tactile acuity) and haptic three-dimensional (3-D) shape discrimination. The results indicated that the blind outperformed their sighted counterparts (individually matched for both age and sex) on both tactile tasks.

Suppression subtractive hybridization reveals differential gene expression in sunflower grown in high P.

Sunflower (Helianthus annuus L.) is a commercially important oilseed crop. Previous studies proved that this crop is a promising plant species for phytoextraction of excess soil phosphorus (P) because of its superior P accumulating characteristics.

Structural and functional effects of acoustic exposure in goldfish: evidence for tonotopy in the teleost saccule.

Background: Mammalian and avian auditory hair cells display tonotopic mapping of frequency along the length of the cochlea and basilar papilla. It is not known whether the auditory hair cells of fishes possess a similar tonotopic organization in the saccule, which is thought to be the primary auditory receptor in teleosts. To investigate this question, we determined the location of hair cell damage in the saccules of goldfish (Carassius auratus) following exposure to specific frequencies.

Interactive effects of lead, copper, nickel and zinc on growth, metal uptake and antioxidative metabolism of Sesbania drummondii.

Sesbania drummondii seedlings were grown in a medium to which lead (Pb), copper (Cu), nickel (Ni) and zinc (Zn) were added singly and in combinations in order to assess the effects of metal interactions on seedling growth, metal accumulation and anti-oxidative system. S. drummondii growth was significantly inhibited with metal treatments.

Conflict management in online relationships.

With the diffusion of networked technology, personal relationships can be easily formed and maintained online today. Similar to a face-to-face situation, conflict is also seen in these online relationships. Early theories suggested that computer-mediated communication (CMC) tends to increase conflicts because of the lack of social-context cues, and CMC is not rich enough to manage conflict.

Effective 3-D shape discrimination survives retinal blur.

A single experiment evaluated observers' ability to visually discriminate 3-D object shape, where the 3-D structure was defined by motion, texture, Lambertian shading, and occluding contours. The observers' vision was degraded to varying degrees by blurring the experimental stimuli, using 2.0-, 2.

A facile photosynthesis of trans-dioxoruthenium(VI) porphyrins.

Photolysis of porphyrin-ruthenium(IV) dichlorate complexes with visible light results in homolytic cleavage of the O-Cl bond in the chlorates to form trans-dioxoruthenium(VI) species bearing either sterically encumbered or unencumbered porphyrin ligands.

Improved automated monitoring and new analysis algorithm for circadian phototaxis rhythms in Chlamydomonas.

Automated monitoring of circadian rhythms is an efficient way of gaining insight into oscillation parameters like period and phase for the underlying pacemaker of the circadian clock. Measurement of the circadian rhythm of phototaxis (swimming towards light) exhibited by the green alga Chlamydomonas reinhardtii has been automated by directing a narrow and dim light beam through a culture at regular intervals and determining the decrease in light transmittance due to the accumulation of cells in the beam. In this study, the monitoring process was optimized by constructing a new computer-controlled measuring machine that limits the test beam to wavelengths reported to be specific for phototaxis and by choosing an algal strain, which does not need background illumination between test light cycles for proper expression of the rhythm.

Aging and the discrimination of object weight.

A single experiment was carried out to evaluate the ability of younger and older observers to discriminate object weights. A 2-alternative forced-choice variant of the method of constant stimuli was used to obtain difference thresholds for lifted weight for twelve younger (mean age = 21.5 years) and twelve older (mean age = 71.

Cell proliferation follows acoustically-induced hair cell bundle loss in the zebrafish saccule.

Fishes are capable of regenerating sensory hair cells in the inner ear after acoustic trauma. However, a time course of auditory hair cell regeneration has not been established for zebrafish. Adult zebrafish (Danio rerio) were exposed to a 100 Hz pure tone at 179 dB re 1 microPa RMS for 36 h and then allowed to recover for 0-14 days before morphological analysis.