Faster polynomial multiplication over finite fields

Let p be a prime, and let M_p(n) denote the bit complexity of multiplying two polynomials in F_p[X] of degree less than n. For n large compared to p, we establish the bound M_p(n) = O(n log n 8^(log^* n) log p), where log^* is the iterated logarithm. This is the first known F\"urer-type complexity bound for F_p[X], and improves on the previously best known bound M_p(n) = O(n log n log log n log p)

The weathering of micrometeorites from the Transantarctic Mountains

Micrometeorites are cosmic dust particles recovered from the Earth's surface that dominate the influx of extraterrestrial material accreting to our planet. This paper provides the first in-depth study of the weathering of micrometeorites within the Antarctic environment that will allow primary and secondary features to be distinguished. It is based on the analysis of 366 particles from Larkman Nunatak and 25 from the Transantarctic Mountain collection. Several important morphological categories of weathering effects were identified: (1) irregular and faceted cavities, (2) surface etch pits, (3) infilled cavities, (4) replaced silicate phases, and (5) hydrated and replaced metal. These features indicate that congruent dissolution of silicate phases, in particular olivine, is important in generating new pore space within particles. Comparison of the preservation of glass and olivine also indicates preferential dissolution of olivine by acidic solutions during low temperature aqueous alteration. Precipitation of new hydrous phases within cavities, in particular ferrihydrite and jarosite, results in pseudomorph textures within heavily altered particles. Glass, in contrast, is altered to palagonite gels and shows a sequential replacement indicative of varying water to rock ratios. Metal is variably replaced by Fe-oxyhydroxides and results in decreases in Ni/Fe ratio. In contrast, sulphides within metal are largely preserved. Magnetite, an essential component of micrometeorites formed during atmospheric entry, is least altered by interaction with the terrestrial environment. The extent of weathering in the studied micrometeorites is sensitive to differences in their primary mineralogy and varies significantly with particle type. Despite these differences, we propose a weathering scale for micrometeorites based on both their degree of terrestrial alteration and the level of encrustation by secondary phases. The compositions and textures of weathering products, however, suggest open system behaviour and variable water to rock ratios that imply climatic variation over the lifetime of the micrometeorite deposits

Animal genetic resource trade flows: Economic assessment

Throughout human history, livestock producers have relied on a vibrant international exchange of genentic resources to achieve improvements in the quality and productivity of their animals. In recent years, however, some observers have argued that changes in the legal, technological, and economic environment now imply that international exchanges of animal genetic resources (AnGR) systematically benefit rich countries at the expense of poor countries. It is argued that international flows of AnGR are displacing the indigenous animal genetic resources of developing countries, and alos that the genetic wealth of the developing world is being expropriated by rich countries. In reaction, there have been growing calls for limitations and/or barriers to the exchange of animal genetic resources. These discussions, however, seem to be based on limited information about the magnitude and direction of current trade flows in AnGR. This paper offers an analysis of AnGR trade flows from 1990 to 2005. The paper draws on national-level data from 150 countries that reported information to the United States Statistics Division. Three major trade categories were evaluated: live cattle and pigs for breeding, and cattle semen. Over the period studied, Europe and North America were the primary exporters of genetic resources for the species evaluated. OECD countries accounted for 98.7, 92.5, and 95% of cattle semen, live cattle, and swine exports in 2005, respectively. In evaluation the direction of trade between developed (North) and developing (South) countries, North-South trade had the largest magnitude, followed by North-South, South-South, and South-North. The data do not support the notion that Southern genetic resources are being used on a large scale in the North. We believe that importation from South to North is limited by the vast discrepancies in production efficiency and production systems between countries in the North and South. Given the low volume of South-North exchange, it seems doubtful that sufficient revenues could be acquired through a “benefit-sharing mechanism" to have any substantial impact on in situ or ex situ conservation efforts, or to generate benefits for poor livestock keepers in developing countries. We question whether global agreements or restrictions on trade will achieve the improving the well-being of the poor. We suggest that resources instead be urgently employed for conservation and that more direct measures should be taken to aid poor farmers, ranchers, and herders in their efforts to conserve genetic resources.animal genetic resources, gene flow, germplasm trade

Multispectral oximetry of murine tendon microvasculature with inflammation

We report a novel multispectral imaging technique for localised measurement of vascular oxygen saturation (SO2) in vivo. Annular back-illumination is generated using a Schwarzchild-design reflective objective. Analysis of multispectral data is performed using a calibration-free oximetry algorithm. This technique is applied to oximetry in mice to measure SO2 in microvasculature supplying inflamed tendon tissue in the hind leg. Average SO2 for controls was 94.8 ± 7.0 % (N = 6), and 84.0 ± 13.5 % for mice with inflamed tendon tissue (N = 6). We believe this to be the first localised measurement of hypoxia in tendon microvasculature due to inflammation. Quantification of localised SO2 is important for the study of inflammatory diseases such as rheumatoid arthritis, where hypoxia is thought to play a role in pathogenesis

Minimally Invasive Optical Biopsy for Oximetry

The study of localised oxygen saturation in blood vessels can shed light on the etiology and progression of many diseases with which hypoxia is associated. For example, hypoxia in the tendon has been linked to early stages of rheumatoid arthritis, an auto-immune inflammatory disease. Vascular oximetry of deep tissue presents significant challenges as vessels are not optically accessible. In this paper, we present a novel multispectral imaging technique for vascular oximetry, and recent developments made towards its adaptation for minimally invasive imaging. We present proof-of-concept of the system and illumination scheme as well as the analysis technique. We present results of a validation study performed in vivo on mice with acutely inflamed tendons. Adaptation of the technique for minimally invasive microendoscopy is also presented, along with preliminary results of minimally invasive ex vivo vascular oximetry

Quantization of Crack Speeds in Dynamic Fracture of Silicon: Multiparadigm ReaxFF Modeling

We report a study of dynamic cracking in a silicon single crystal in which the ReaxFF reactive force field is used for about 3,000 atoms near the crack tip while the other 100,000 atoms of the model system are described with a simple nonreactive force field. The ReaxFF is completely derived from quantum mechanical calculations of simple silicon systems without any empirical parameters. This model has been successfully used to study crack dynamics in silicon, capable of reproducing key experimental results such as orientation dependence of crack dynamics (Buehler et al., Phys. Rev. Lett. 2006). In this article, we focus on crack speeds as a function of loading and crack propagation mechanisms. We find that the steady state crack speed does not increase continuously with applied load, but instead jumps to a finite value immediately after the critical load, followed by a regime of slow increase. Our results quantitatively reproduce experimental observations of crack speeds during fracture in silicon along the (111) planes, confirming the existence of lattice trapping effects. We observe similar effects in the (110) crack direction

Mitochondrial and chloroplast stress responses are modulated in distinct touch and chemical inhibition phases

Previous studies have identified a range of transcription factors that modulate retrograde regulation of mitochondrial and chloroplast functions in Arabidopsis (Arabidopsis thaliana). However, the relative importance of these regulators and whether they act downstream of separate or overlapping signaling cascades is still unclear. Here, we demonstrate that multiple stress-related signaling pathways, with distinct kinetic signatures, converge on overlapping gene sets involved in energy organelle function. The transcription factor ANAC017 is almost solely responsible for transcript induction of marker genes around 3 to 6 h after chemical inhibition of organelle function and is a key regulator of mitochondrial and specific types of chloroplast retrograde signaling. However, an independent and highly transient gene expression phase, initiated within 10 to 30 min after treatment, also targets energy organelle functions, and is related to touch and wounding responses. Metabolite analysis demonstrates that this early response is concurrent with rapid changes in tricarboxylic acid cycle intermediates and large changes in transcript abundance of genes encoding mitochondrial dicarboxylate carrier proteins. It was further demonstrated that transcription factors AtWRKY15 and AtWRKY40 have repressive regulatory roles in this touch-responsive gene expression. Together, our results show that several regulatory systems can independently affect energy organelle function in response to stress, providing different means to exert operational control

Parasitoid load affects plant fitness in a tritrophic system

Plants attacked by herbivorous insects emit volatile compounds that attract predators or parasitoids of the herbivores. Plant fitness increases when these herbivorous insects are parasitized by solitary parasitoids, but whether gregarious koinobiont parasitoids also confer a benefit to plant fitness has been disputed. We investigated the relationship between parasitoid load of the gregarious Cotesia glomerata (L.) (Hymenoptera: Braconidae), food consumption by larvae of their host Pieris brassicae L. (Lepidoptera: Pieridae), and seed production in a host plant, Brassica nigra L. (Brassicaceae), in a greenhouse experiment. Plants damaged by caterpillars containing single parasitoid broods produced a similar amount of seeds as undamaged control plants and produced significantly more seeds than plants with unparasitized caterpillars feeding on them. Increasing the parasitoid load to levels likely resulting from superparasitization, feeding by parasitized caterpillars was significantly negatively correlated with plant seed production. Higher parasitoid brood sizes were negatively correlated with pupal weight of Cotesia glomerata, revealing scramble competition leading to a fitness trade-off for the parasitoid. Our results suggest that in this tritrophic system plant fitness is higher when the gregarious parasitoid deposits a single brood into its herbivorous host. A prediction following from these results is that plants benefit from recruiting parasitoids when superparasitization is prevented. This is supported by our previous results on down-regulation of synomone production when Brassica oleracea was fed on by parasitized caterpillars of P. brassicae. We conclude that variable parasitoid loads in gregarious koinobiont parasitoids largely explain existing controversies about the putative benefit of recruiting these parasitoids for plant reproduction

The Impact of Fast ForWord on MCT Scores and Student Achievement

Educators today were concerned with how the No Child Left Behind Act of 2001 dealt with the improvement of education throughout the United States. Schools should have put forth a greater effort and reduced the achievement gap between different groups of students based on race, gender, special education status, and if that student was economically disadvantaged. A problem was identified as low student MCT scores in the state of Mississippi. A tutorial method that claimed to help improve students in the areas of reading and language was identified as Fast ForWord. This study set out to find if there was a significant improvement in student Mississippi Curriculum Test (MCT) reading and language scores after students completed the computer based program Fast ForWord. This study also set out to find if the teachers, teacher assistants, parents and administrators had a positive perception by about the Fast ForWord program. In other words did they feel the program improved student MCT reading and language scores? A sample of two hundred fifty one students was utilized in this study. A sample of one hundred four educators and parents was utilized in this study also. The survey measured the perception that educators and parents had about the Fast ForWord program. The instrument measured the academic gain or loss by students in grades six through eight who had successfully completed the Fast ForWord program. The survey data was examined by reviewing all the variables in the descriptive statistics. The study found that administrators had a higher level of confidence than any of the other groups of educators or the parents. A paired samples t-test was used to compare the MCT reading and language scores before and after completing the Fast ForWord program. The finding was not positive so the researcher ran a Pearson Chi-Square test to find out exactly how many students improved, stayed the same, or decreased their MCT reading or language score. The finding was that the majority of students either remained at the same level of proficiency or dropped a level of proficiency after completing the Fast ForWord