An Automated Method for Tracking Clouds in Planetary Atmospheres

We present an automated method for cloud tracking which can be applied to planetary images. The method is based on a digital correlator which compares two or more consecutive images and identifies patterns by maximizing correlations between image blocks. This approach bypasses the problem of feature detection. Four variations of the algorithm are tested on real cloud images of Jupiter’s white ovals from the Galileo mission, previously analyzed in Vasavada et al. [Vasavada, A.R., Ingersoll, A.P., Banfield, D., Bell, M., Gierasch, P.J., Belton, M.J.S., Orton, G.S., Klaasen, K.P., Dejong, E., Breneman, H.H., Jones, T.J., Kaufman, J.M., Magee, K.P., Senske, D.A. 1998. Galileo imaging of Jupiter’s atmosphere: the great red spot, equatorial region, and white ovals. Icarus, 135, 265, doi:10.1006/icar.1998.5984]. Direct correlation, using the sum of squared differences between image radiances as a distance estimator (baseline case), yields displacement vectors very similar to this previous analysis. Combining this distance estimator with the method of order ranks results in a technique which is more robust in the presence of outliers and noise and of better quality. Finally, we introduce a distance metric which, combined with order ranks, provides results of similar quality to the baseline case and is faster. The new approach can be applied to data from a number of space-based imaging instruments with a non-negligible gain in computing time

A Cloud Tracking Tool for Planetary Orbiter Images

During their operations phase, planetary missions continuously produce a wealth of data that tend to overwhelm research teams. Spectral imagers, in particular, produce data cubes in which the wavelength dimension adds to the two spatial dimensions. Tracking of atmospheric features in order to derive winds and the construction of global maps from such large data volumes becomes particularly time-consuming if done manually. This highlights the importance of automated procedures capable of analysing sequences of data cubes with minimal user interaction. A tool for cloud tracking for such a purpose is currently under development in our group. In its present state it is based on synthetic images and uses a simple method of multiple matrix comparison to derive wind components. Deriving winds from data from the Venus Express - Visible and InfraRed Thermal Imaging Spectrometer (VIRTIS) instrument will be a possible application. We shall present an overview of the method, its benchmarking and the current status and future development of the project

Relationship Between First-Year Student Retention, Noncognitive Risk Factors, and Student Advising

It is well established that such student precollege cognitive measures as high school GPA and test scores (ACT, SAT) have a certain predictive value in student retention. While research is replete with evidence of the value of student advising in a college’s retention strategy, there is a gap in the literature on the impact of using noncognitive survey information by advisors to better target student deficiencies. The primary goal of this study was to explore the relationship between retention and exposure to noncognitive risk factor information for students and advisors. One thousand fifty-four freshmen students enrolled in a first-year experience (FYE) course at Dixie State College were given the Student Strengths Inventory (SSI) survey that measures six different noncognitive risk factor variables. By using a regression discontinuity design, students were initially divided into two sample groups using an index score generated by combining the high school GPA and ACT (or equivalent) test score. Students who fell below the cutoff point were further subdivided by random sampling into three groups: (a) students who received their survey results with no further action, (b) students selected for general advisement, and (c) students selected for targeted advisement using the survey results. When comparing the retention rates from fall semester 2009 to fall semester 2010, the retention rates varied as predicted by the researcher; however, these differences in retention could not be attributed to the usage of the survey with one exception: when the treatment group was filtered only to include first-generation students, usage of the survey results was statistically significant in contributing to a 62% retention rate, the highest of any of the sample groups studied

Sleep dysfunction and EEG alterations in mice overexpressing alpha-synuclein.

BackgroundSleep disruptions occur early and frequently in Parkinson's disease (PD). PD patients also show a slowing of resting state activity. Alpha-synuclein is causally linked to PD and accumulates in sleep-related brain regions. While sleep problems occur in over 75% of PD patients and severely impact the quality of life of patients and caregivers, their study is limited by a paucity of adequate animal models.ObjectiveThe objective of this study was to determine whether overexpression of wildtype alpha-synuclein could lead to alterations in sleep patterns reminiscent of those observed in PD by measuring sleep/wake activity with rigorous quantitative methods in a well-characterized genetic mouse model.MethodsAt 10 months of age, mice expressing human wildtype alpha-synuclein under the Thy-1 promoter (Thy1-aSyn) and wildtype littermates underwent the subcutaneous implantation of a telemetry device (Data Sciences International) for the recording of electromyograms (EMG) and electroencephalograms (EEG) in freely moving animals. Surgeries and data collection were performed without knowledge of mouse genotype.ResultsThy1-aSyn mice showed increased non-rapid eye movement sleep during their quiescent phase, increased active wake during their active phase, and decreased rapid eye movement sleep over a 24-h period, as well as a shift in the density of their EEG power spectra toward lower frequencies with a significant decrease in gamma power during wakefulness.ConclusionsAlpha-synuclein overexpression in mice produces sleep disruptions and altered oscillatory EEG activity reminiscent of PD, and this model provides a novel platform to assess mechanisms and therapeutic strategies for sleep dysfunction in PD

Notas sobre la biología del bigete scad, Selar crumenophthalmus (Carangidae), en la isla Reunión, suroeste del océano Índico

The main characteristics of the biology of bigeye scad were studied from commercial fishery catches around Reunion Island. Biometric relationships were calculated. The monitoring of size distribution, aggregated by month, allowed us to estimate the theoretical growth equation using the ELEFAN software. The von Bertalanffy growth parameters were adjusted with a seasonal modulation: L∞ = 265 mm; K = 1.64 year-1; c = 0.068; j = 0.38. The growth of the cohort was quite high during the austral summer (November–April) and decreased during the austral winter (May-October). The arrival of a new cohort with homogeneous small sizes (65 to 90 mm) in the fishery in November coincided with the disappearance of large individuals. A feature of the reproductive biology was that the sex ratio remained constant month by month and that there was no predominance of male or female even in the larger size classes. Fish were mature by April and the proportion of mature fish progressively increased until November, when the gonad-indices were the highest. The size at first maturity (L50) was reached at 215 mm (fork length). The largest specimens observed were 255 mm long (fork length). After reproduction, massive mortality occurred and few individuals survived.Las principales características de la biología del Selar crumenophtalmus fueron estudiadas en la isla Reunión utilizando los desembarques comerciales. Se calcularon las relaciones biométricas. El seguimiento de la distribución mensual de la longitud nos permitió estimar la ecuación de la curva de crecimiento teórico, utilizando el programa ELEFAN. Los parámetros del modelo de crecimiento de Von Bertalanffy fueron ajustados con una modulación estacional: L∞ = 265 mm; K = 1.64 year-1; c = 0.068; j = 0.38. La tasa de crecimiento de las cohortes fue muy rápida durante el verano austral (noviembre-abril) y disminuyó durante el invierno (mayo-octubre). La llegada de una nueva cohorte de pequeños individuos de longitud homogénea (65-90 mm) a la pesquería en noviembre, coincidió con la desaparición de los individuos más grandes. La relación de sexos permaneció constante a lo largo del año y no se vio una superioridad numérica de los machos o de las hembras, ni en las clases de tamaño más grandes. Los primeros peces maduros fueron observados desde el mes de abril y la proporción creció hasta noviembre (índice gonadosomático máximo). La talla de primera madurez (L50) fue alcanzada a los 215 mm (longitud furca, LF). Los peces más grandes observados midieron 255 mm (LF). Después de la reproducción, ocurrió una mortalidad masiva y pocos individuos sobrevivieron

Endpoint sparse domination for classes of multiplier transformations

We prove endpoint results for sparse domination of translation invariant multiscale operators. The results are formulated in terms of dilation invariant classes of Fourier multipliers based on natural localized $M^{p\to q}$ norms which express appropriate endpoint regularity hypotheses. The applications include new and optimal sparse bounds for classical oscillatory multipliers and multi-scale versions of radial bump multipliers.Comment: 55 pages, 1 figur

Bochner-Riesz means at the critical index: Weighted and sparse bounds

We consider Bochner-Riesz means on weighted $L^p$ spaces, at the critical index $\lambda(p)=d(\frac 1p-\frac 12)-\frac 12$. For every $A_1$-weight we obtain an extension of Vargas' weak type $(1,1)$ inequality in some range of $p>1$. To prove this result we establish new endpoint results for sparse domination. These are almost optimal in dimension $d=2$; partial results as well as conditional results are proved in higher dimensions. For the means of index $\lambda_*=\frac{d-1}{2d+2}$ we prove fully optimal sparse bounds.Comment: 39 pages, 1 figur

Lean, green, mean, obscene…? What is efficiency? And is it sustainable? Animal production and consumption reconsidered

First paragraph: “Food systems need to become more efficient. We need to produce food in ways that use fewer resources and generate fewer negative environmental impacts. This drive towards efficiency is essential if we are to achieve more sustainable food systems.”  Such is the typical conclusion of numerous policy documents and industry statements, based on academic papers published in agricultural science and life cycle assessment journals.  It is a well-rehearsed observation that the food system today is undermining the environment upon which future food production depends. We know too that given current trends, our problems are set to grow, not just because our population is growing, meaning more mouths to feed, but also because our food demands are changing. As people on average become richer, they demand and can afford not just more food, but more of the foods that they like, notably those of animal origin. The rearing of animals for flesh, eggs and milk generates some 14.5% of total global GHG emissions, occupies 70% of agricultural land and is the main cause of the environmental problems such as biodiversity loss and water pollution.1,2 Moving from land to water, there are major concerns about the depletion of wild fish stocks and the negative effects of over fishing on aquatic ecosystems. Aquaculture production bridges and is linked to concerns in both the terrestrial and aquatic domains: it is a user of land based resources, but its production has been underpinned in recent years on wild fish stocks used as feed inputs.  While there is general agreement that action is needed to address the environmental problems caused by the food system, what such ‘action’ should be is the subject of substantial attention and debate within the policy, academic, business and NGO communities. One word that comes up time and again in discussions about the way forward is ‘efficiency.&rsquo

The pan-genome of Lactobacillus reuteri strains originating from the pig gastrointestinal tract

Background Lactobacillus reuteri is a gut symbiont of a wide variety of vertebrate species that has diversified into distinct phylogenetic clades which are to a large degree host-specific. Previous work demonstrated host specificity in mice and begun to determine the mechanisms by which gut colonisation and host restriction is achieved. However, how L. reuteri strains colonise the gastrointestinal (GI) tract of pigs is unknown. Results To gain insight into the ecology of L. reuteri in the pig gut, the genome sequence of the porcine small intestinal isolate L. reuteri ATCC 53608 was completed and consisted of a chromosome of 1.94 Mbp and two plasmids of 138.5 kbp and 9.09 kbp, respectively. Furthermore, we generated draft genomes of four additional L. reuteri strains isolated from pig faeces or lower GI tract, lp167-67, pg-3b, 20-2 and 3c6, and subjected all five genomes to a comparative genomic analysis together with the previously completed genome of strain I5007. A phylogenetic analysis based on whole genomes showed that porcine L. reuteri strains fall into two distinct clades, as previously suggested by multi-locus sequence analysis. These six pig L. reuteri genomes contained a core set of 1364 orthologous gene clusters, as determined by OrthoMCL analysis, that contributed to a pan-genome totalling 3373 gene clusters. Genome comparisons of the six pig L. reuteri strains with 14 L. reuteri strains from other host origins gave a total pan-genome of 5225 gene clusters that included a core genome of 851 gene clusters but revealed that there were no pig-specific genes per se. However, genes specific for and conserved among strains of the two pig phylogenetic lineages were detected, some of which encoded cell surface proteins that could contribute to the diversification of the two lineages and their observed host specificity. Conclusions This study extends the phylogenetic analysis of L. reuteri strains at a genome-wide level, pointing to distinct evolutionary trajectories of porcine L. reuteri lineages, and providing new insights into the genomic events in L. reuteri that occurred during specialisation to their hosts. The occurrence of two distinct pig-derived clades may reflect differences in host genotype, environmental factors such as dietary components or to evolution from ancestral strains of human and rodent origin following contact with pig populations

Secretory traffic in the eukaryotic parasite Toxoplasma gondii: less is more

Name a single-celled eukaryote that boasts a small genome size, is easily cultivated in haploid form, for which a wide variety of molecular genetic tools are available, and that exhibits a simple, polarized secretory apparatus with a well-defined endoplasmic reticulum and Golgi that can serve as a model for understanding secretion. Got it? Now name a cell with all these attributes that contains at least a dozen distinct and morphologically well-defined intracellular organelles, including three distinct types of secretory vesicles and two endosymbiotic organelles. Not so sure anymore