"The upper limits of vegetation on Mauna Loa, Hawaii": a 50th-anniversary reassessment.

In January 1958, a survey of alpine flora was conducted along a recently constructed access road across the upper volcanic slopes of Mauna Loa, Hawaii (2525-3397 m). Only five native Hawaiian species were encountered on sparsely vegetated historic and prehistoric lava flows adjacent to the roadway. A resurvey of roadside flora in 2008 yielded a more than fourfold increase to 22 species, including nine native species not previously recorded. Eight new alien species have now invaded this alpine environment, although exclusively limited to a few individuals in ruderal habitat along the roadway. Alternative explanations for species invasion and altitudinal change over the past 50 years are evaluated: (1) changes related to continuing primary succession on ameliorating (weathering) young lava substrates; (2) local climate change; and (3) road improvements and increased vehicular access which promote enhanced car-borne dispersal of alien species derived from the expanding pool of potential colonizers naturalized on the island in recent decades. Unlike alpine environments in temperate latitudes, the energy component (warming) in climate change on Mauna Loa does not appear to be the unequivocal driver of plant invasion and range extension. Warming may be offset by other climate change factors including rainfall and evapotranspiration.

Nanoparticle temperature estimation in combined ac and dc magnetic fields.

The harmonics produced by the nonlinear magnetization of superparamagnetic nanoparticles have been utilized in a number of budding medical devices. Here we expand on an earlier technique for quantitatively measuring nanoparticle temperature in a purely ac field by including the presence of a static field. The ability to quantify nanoparticle temperature by tracking changes in the 4th/2nd harmonic ratio is presented and shown to achieve an accuracy of 0.79 K. The advantage of even harmonics, issues with odd harmonics in the presence of a static field and the potential for future incorporation into an imaging system are discussed.

Magnetic nanoparticle temperature estimation.

The authors present a method of measuring the temperature of magnetic nanoparticles that can be adapted to provide in vivo temperature maps. Many of the minimally invasive therapies that promise to reduce health care costs and improve patient outcomes heat tissue to very specific temperatures to be effective. Measurements are required because physiological cooling, primarily blood flow, makes the temperature difficult to predict a priori. The ratio of the fifth and third harmonics of the magnetization generated by magnetic nanoparticles in a sinusoidal field is used to generate a calibration curve and to subsequently estimate the temperature. The calibration curve is obtained by varying the amplitude of the sinusoidal field. The temperature can then be estimated from any subsequent measurement of the ratio. The accuracy was 0.3 degree K between 20 and 50 degrees C using the current apparatus and half-second measurements. The method is independent of nanoparticle concentration and nanoparticle size distribution.

Utility of the dentin matrix protein 1 (DMP1) gene for resolving mammalian intraordinal phylogenetic relationships.

We sequenced exon 6 of the nuclear dentin matrix protein 1 (DMP1) gene from 19 species of bats (order Chiroptera) to assess the utility of this gene for higher-level phylogenetic studies. Bayesian analysis revealed high support (posterior probabilities >/=0.95) for monophyly of Noctilionoidea (Phyllostomidae, Noctilionidae, and Mormoopidae), all genera and most families examined. Comparison of the phylogenetic information present in DMP1 with mitochondrial rDNA and nuclear RAG2 genes indicated no significant heterogeneity. Thus, we concatenated these three data sets into a single "total evidence" phylogenetic analysis. Combined analysis was congruent with study of RAG2 and combined RAG2 and mtrDNA sequences, but improved support (Bayesian posterior probabilities) for many nodes. Our results indicate that exon 6 of DMP1 is rapidly evolving, able to tolerate non-frame shifting insertion and deletion events, is more variable than RAG2, and provides phylogenetic resolution from the interfamilial to infraclass levels in mammals.

Characterization and phylogenetic utility of the mammalian protamine p1 gene.

We sequenced the protamine P1 gene (ca. 450 bp) from 20 bats (order Chiroptera) and the flying lemur (order Dermoptera). We compared these sequences with published sequences from 19 other mammals representing seven orders (Artiodactyla, Carnivora, Cetacea, Perissodactyla, Primates, Proboscidea, and Rodentia) to assess structure, base compositional bias, and phylogenetic utility. Approximately 80% of second codon positions were guanine, resulting in protamine proteins containing a high frequency of arginine residues. Our data indicate that codon usage for arginine differs among higher mammalian taxa. Parsimony analysis of 40 species representing nine orders produced a well-resolved tree in which most nodes were supported strongly, except at the lowest taxonomic levels (e.g., within Artiodactyla and Vespertilionidae). These data support monophyly of several taxa proposed by morphologic and molecular studies (all nine orders: Laurasiatheria, Cetartiodactytla, Yangochiroptera, Noctilionoidea, Rhinolophoidea, Vespertilionoidea, Phyllostomidae, Natalidae, and Vespertilionidae) and, in agreement with recent molecular studies, reject monophyly of Archonta, Volitantia, and Microchiroptera. Bats were sister to a clade containing Perissodactyla, Carnivora, and Cetartiodactyla, and, although not unequivocally, rhinolophoid bats (traditional microchiropterans) were sister to megachiropterans. Sequences of the protamine P1 gene are useful for resolving relationships at and above the familial level in bats, and generally within and among mammalian orders, but with some drawbacks. The coding and intervening sequences are small, producing few phylogenetically informative characters, and aligning the intron is difficult, even among closely related families. Given these caveats, the protamine P1 gene may be important to future systematic studies because its functional and evolutionary constraints differ from other genes currently used in systematic studies.