Shoot growth dynamics and photosynthetic response to increased nitrogen availability in the alpine willow salix-glauca

Plants subjected to increases in the supply of resource(s) limiting growth may allocate more of those resources to existing leaves, increasing photosynthetic capacity, and/or to production of more leaves, increasing whole-plant photosynthesis. The responses of three populations of the alpine willow, Salix glauca, growing along an alpine topographic sequence representing a gradient in soil moisture and organic matter, and thus potential N supply, to N amendments, were measured over two growing seasons, to elucidate patterns of leaf versus shoot photosynthetic responses. Leaf-(foliar N, photosynthesis rates, photosynthetic N-use efficiency) and shoot-(leaf area per shoot, number of leaves per shoot, stem weight, N resorption efficiency) level measurements were made to examine the spatial and temporal variation in these potential responses to increased N availability. The predominant response of the willows to N fertilization was at the shoot-level, by production of greater leaf area per shoot. Greater leaf area occurred due to production of larger leaves in both years of the experiment and to production of more leaves during the second year of fertilization treatment. Significant leaf-level photosynthetic response occurred only during the first year of treatment, and only in the dry meadow population. Variation in photosynthesis rates was related more to variation in stomatal conductance than to foliar N concentration. Stomatal conductance in turn was significantly related to N fertilization. Differences among the populations in photosynthesis, foliar N, leaf production, and responses to N fertilization indicate N availability may be lowest in the dry meadow population, and highest in the ridge population. This result is contrary to the hypothesis that a gradient of plant available N corresponds with a snowpack/topographic gradient.

Multiple Health Behavior Changes and Co-variation in a Telephone Counseling Trial

Background Delivering effective multiple health behavior interventions to large numbers of adults with chronic conditions via primary care settings is a public health priority. Purpose Within a 12-month, telephone-delivered diet and physical activity intervention with multiple behavioral outcomes, we examined the extent and co-variation of multiple health behavior change. Methods A cluster-randomized trial with 434 patients with type 2 diabetes or hypertension were recruited from 10 general practices, which were randomized to receive telephone counseling or usual care. Results Those receiving telephone counseling were significantly more likely than those in usual care to make greater reductions in multiple behaviors after adjusting for baseline risk behaviors (OR 2.42; 95%CI 1.43, 4.11). Controlling for baseline risk and group allocation, making changes to either physical activity, fat, vegetable, or fiber intake was associated with making significantly more improvements in other behaviors. Conclusions For patients with chronic conditions, telephone counseling can significantly improve multiple health behaviors, with behavioral changes tending to co-vary.

Quantification of the relationship between Fuser Roller Temperature and Laser Printer Emissions

Recently published studies not only demonstrated that laser printers are often significant sources of ultrafine particles, but they also shed light on particle formation mechanisms. While the role of fuser roller temperature as a factor affecting particle formation rate has been postulated, its impact has never been quantified. To address this gap in knowledge, this study measured emissions from 30 laser printers in chamber using a standardized printing sequence, as well as monitoring fuser roller temperature. Based on a simplified mass balance equation, the average emission rates of particle number, PM2.5 and O3 were calculated. The results showed that: almost all printers were found to be high particle number emitters (i.e. > 1.01×1010 particles/min); colour printing generated more PM2.5 than monochrome printing; and all printers generated significant amounts of O3. Particle number emissions varied significantly during printing and followed the cycle of fuser roller temperature variation, which points to temperature being the strongest factor controlling emissions. For two sub-groups of printers using the same technology (heating lamps), systematic positive correlations, in the form of a power law, were found between average particle number emission rate and average roller temperature. Other factors, such as fuser material and structure, are also thought to play a role, since no such correlation was found for the remaining two sub-groups of printers using heating lamps, or for the printers using heating strips. In addition, O3 and total PM2.5 were not found to be statistically correlated with fuser temperature.

Bias in the nonlinear filter generator output sequence

Nonlinear filter generators are common components used in the keystream generators for stream ciphers and more recently for authentication mechanisms. They consist of a Linear Feedback Shift Register (LFSR) and a nonlinear Boolean function to mask the linearity of the LFSR output. Properties of the output of a nonlinear filter are not well studied. Anderson noted that the m-tuple output of a nonlinear filter with consecutive taps to the filter function is unevenly distributed. Current designs use taps which are not consecutive. We examine m-tuple outputs from nonlinear filter generators constructed using various LFSRs and Boolean functions for both consecutive and uneven (full positive difference sets where possible) tap positions. The investigation reveals that in both cases, the m-tuple output is not uniform. However, consecutive tap positions result in a more biased distribution than uneven tap positions, with some m-tuples not occurring at all. These biased distributions indicate a potential flaw that could be exploited for cryptanalysis

Complete Nucleotide Sequence of Rice Tungro Spherical Virus Genome of a Highly Virulent Strain Vt6

The complete nucleotide sequence of rice tungro spherical virus (RTSV) strain Vt6, originally from Mindanao, the Philippines, with higher virulence to resistant rice cultivars, was determined and compared with the published sequence for the Philippine-type strain A (RTSV-A-Shen). It was reported that RTSV-A was not able to infect a rice resistant cultivar TKM 6 (10). RTSV-Vt6 and RTSV-A-Shen share 90% and 95% homology at nucleotide and amino-acid levels, respectively. The N-terminal leader sequence of RTSV-Vt6 contained a 39-amino acids-region (positions 65 to 103) which was totally different from that of RTSV-A-Shen; the difference resulted from frame shifting by nucleotide insertions and deletions. To confirm the amino-acid sequence differences of the leader polypeptide, the same region was cloned and sequenced using a newly obtained variant of RTSV-type 6, which had been collected in the field of IRRI, and seven field isolates from Mindanao, the Philippines. Since all the sequences of the target region are identical to that of the Vt6 leader polypeptide, the sequence difference in the leader region seems not to correlate with the virulence of Vt6.

Petrology and geochemistry of the Quaternary Caldera-forming, Phonolitic Granadilla Eruption, Tenerife (Canary Islands)

The Granadilla eruption at 600 ka was one of the largest phonolitic explosive eruptions from the Las Cañadas volcano on Tenerife, producing a classical plinian eruptive sequence of a widespread pumice fall deposit overlain by an ignimbrite. The eruption resulted in a major phase of caldera collapse that probably destroyed the shallow-level magma chamber system. Granadilla pumices contain a diverse phenocryst assemblage of alkali feldspar + biotite + sodian diopside to aegirine–augite + titanomagnetite + ilmenite + nosean/haüyne + titanite + apatite; alkali feldspar is the dominant phenocryst and biotite is the main ferromagnesian phase. Kaersutite and partially resorbed plagioclase (oligoclase to sodic andesine) are present in some eruptive units, particularly in pumice erupted during the early plinian phase, and in the Granadilla ignimbrite at the top of the sequence. Associated with the kaersutite and plagioclase are small clots of microlitic plagioclase and kaersutite interpreted as quenched blebs of tephriphonolitic magma within the phonolite pumice. The Granadilla Member has previously been recognized as an example of reverse-then-normal compositional zonation, where the zonation is primarily expressed in terms of substantial variations in trace element abundances with limited major element variation (cryptic zonation). Evidence for cryptic zonation is also provided by the chemistry of the phenocryst phases, and corresponding changes in intensive parameters (e.g. T, f O2, f  H2O). Geothermometry estimates indicate that the main body of phonolite magma had a temperature gradient from 860 °C to ∼790 °C, with hotter magma (≥900 °C) tapped at the onset and terminal phases of the eruption. The reverse-then-normal chemical and thermal zonation reflects the initial tapping of a partially hybridized magma (mixing of phonolite and tephriphonolite), followed by the more sequential tapping of a zoned and relatively large body of highly evolved phonolite at a new vent and during the main plinian phase. This suggests that the different magma types within the main holding chamber could have been laterally juxtaposed, as well as in a density-stratified arrangement. Correlations between the presence of mixed phenocryst populations (i.e. presence of plagioclase and kaersutite) and coarser pumice fall layers suggest that increased eruption vigour led to the tapping of hybridized and/or less evolved magma probably from greater depths in the chamber. New oxygen isotope data for glass and mineral separates preclude syn-eruptive interaction between the vesiculating magma and hydrothermal fluids as the cause of the Sr isotope disequilibrium identified previously for the deposit. Enrichment in radiogenic Sr in the pumice glass has more likely been due to low-temperature exchange with meteoric water that was enriched in 87Sr by sea spray, which may be a common process affecting porous and glassy pyroclastic deposits on oceanic islands.