Comment on "A well-preserved Archaeopteryx specimen with theropod features"

On the basis of new information from the 10th specimen of Archaeopteryx, Mayr et al. (Reports, 2 December 2005, p. 1483) suggested that birds, or avian flight, originated twice. We investigate the statistical support for this phylogenetic hypothesis and show that it is no better supported by available morphological character data than the hypothesis of a single avian origin.     

Comment on "Productivity is a poor predictor of plant species richness"

Adler et al. (Reports, 23 September 2011, p. 1750) analyzed the standardized sampling data from 48 herbaceous-dominated plant communities and concluded that "Productivity is a poor predictor of plant species richness" at fine-scale. However, their method was biased toward site-number-dominated plant communities. They also failed to provide enough data for regional analysis and detailed information for within-site analysis.     

Comment on "Drought-induced reduction in global terrestrial net primary production from 2000 through 2009"

Zhao and Running (Reports, 20 August 2010, p. 940) reported a reduction in global terrestrial net primary production (NPP) from 2000 through 2009. We argue that the small trends, regional patterns, and interannual variations that they describe are artifacts of their NPP model. Satellite observations of vegetation activity show no statistically significant changes in more than 85% of the vegetated lands south of 70°N during the same 2000 to 2009 period.     

Enzyme changes in flight muscle correlated with aging and flight ability in the male housefly

Magnesium-activated adenosine triphosphatase activity in the giant mitochondria (sarcosomes) of the flight muscle of aging male houseflies decreases concomitantly with failure in flight as reflected in the loss of wings during the second week of adult life. Preceding the loss of wings, however, there is a rapid decline in the activity of an alpha-glycerophosphate dehydrogenase which is located in the extramitochondrial fraction and is dependent on nicotinamide adenine dinucleotide.     

Comment on "Global trends in wind speed and wave height"

Young et al. (Reports, 22 April 2011, p. 451) reported trends in global mean wind speed much larger than found by other investigators. Their report fails to reference these other investigations and does not discuss the consequences that such large wind trends would have on global evaporation and precipitation. The difference between their altimeter and buoy trends suggests a relatively large trend error.     

Comment on "Decagonal and quasi-crystalline tilings in medieval Islamic architecture"

Lu and Steinhardt (Reports, 23 February 2007, p. 1106) claimed the discovery of a large, potentially quasi-crystalline Islamic tiling in the Darb-i Imam shrine but regard the earlier Maragha tiling, previously described as quasiperiodic, as a small isolated motif. We demonstrate that the Darb-i Imam pattern is periodic and that the quasi-crystalline discs superimposed on its lattice are derivatives of the Maragha pattern.     

Comment on "Detecting awareness in the vegetative state"

Owen et al. (Brevia, 8 September 2006, p. 1402) claimed that a patient's brain activity revealed that she was consciously responding to commands despite being in a vegetative state. However, several alternative explanations were not eliminated. Specifically, the activity could reflect unconscious reactions to the last word in the command, not conscious decisions to respond. A refined experimental design could clarify these issues.     

Comment on "Pairing and phase separation in a polarized Fermi gas"

Partridge et al. (Reports, 27 January 2006, p. 503) reported pairing and phase separation in a polarized Fermi gas. We argue that it is not possible to distinguish the superfluid from the normal regimes in the presented data, or to discern which clouds were phase-separated. Some of the reported conclusions are inconsistent with recent experiments.     

Comment on "100% accuracy in automatic face recognition"

Jenkins and Burton (Brevia, 25 January 2008, p. 435) reported that image averaging increased the accuracy of the automatic face recognition to 100% and thus could be applied to photo-identification documents. We argue that the feasibility of image averaging on identification documents is not fully supported by the presented evidence.     

Comment on "Genetically determined differences in learning from errors"

Klein et al. (Reports, 7 December 2007, p. 1642) used individuals with a polymorphism adjacent to the dopamine receptor 2 gene as naturally occurring models for reduced brain dopamine receptor density in a probabilistic learning task. We raise the concern that this polymorphism resides in the gene for the kinase ANKK1, where it causes a nonconservative amino acid exchange.     

Comment on "Plant species richness and ecosystem multifunctionality in global drylands"

Maestre et al. (Reports, 13 January 2012, p. 214) reported a general, but weak, positive relationship between plant diversity and ecosystem multifunctionality in global drylands. We show that the strength of this relationship changes consistently along multiple environmental gradients, becoming strongly positive in stressed habitats. This suggests that biodiversity loss may have especially strong consequences in harsh environments.     

Comment on "Illusions promote mating success in great bowerbirds"

Kelley and Endler (Reports, 20 January 2012, p. 335) claim that male great bowerbirds construct a visual illusion, using display object gradients, that affects mating success. We argue that they provide inadequate statistical support for their hypothesis, inappropriately exclude important data, and do not consider other display traits that explain mating success. We propose a more plausible alternative hypothesis to explain display object patterns.     

Comment on "Wetland sedimentation from hurricanes Katrina and Rita"

Turner et al. (Reports, 20 October 2006, p. 449) measured sedimentation from Hurricanes Katrina and Rita in coastal Louisiana and inferred that storm deposition overwhelms direct Mississippi River sediment input. However, their annualized hurricane deposition rate is overestimated, whereas riverine deposition is underestimated by at least an order of magnitude. Their numbers do not provide a credible basis for decisions about coastal restoration.     

Comment on "Evidence for positive epistasis in HIV-1"

Bonhoeffer et al. (Reports, 26 November 2004, p. 1547) presented evidence for positive epistasis in a clinical data set of HIV-1 mutants and corresponding fitness values. We demonstrate that biases in the original and simulated data sets may lead to erroneous evidence for epistasis. More rigorous statistical tests must be used to account for such biases before one can infer epistasis.