Low-density series expansions for directed percolation I: A new efficient algorithm with applications to the square lattice

A new algorithm for the derivation of low-density series for percolation on directed lattices is introduced and applied to the square lattice bond and site problems. Numerical evidence shows that the computational complexity grows exponentially, but with a growth factor \lambda < \protect{\sqrt[8]{2}}, which is much smaller than the growth factor \lambda = \protect{\sqrt[4]{2}} of the previous best algorithm. For bond (site) percolation on the directed square lattice the series has been extended to order 171 (158). Analysis of the series yields sharper estimates of the critical points and exponents.Comment: 20 pages, 8 figures (3 of them > 1Mb

A conserved circadian function for the Neurofibromatosis 1 gene

Summary: Loss of the Neurofibromatosis 1 (Nf1) protein, neurofibromin, in Drosophila disrupts circadian rhythms of locomotor activity without impairing central clock function, suggesting effects downstream of the clock. However, the relevant cellular mechanisms are not known. Leveraging the discovery of output circuits for locomotor rhythms, we dissected cellular actions of neurofibromin in recently identified substrates. Herein, we show that neurofibromin affects the levels and cycling of calcium in multiple circadian peptidergic neurons. A prominent site of action is the pars intercerebralis (PI), the fly equivalent of the hypothalamus, with cell-autonomous effects of Nf1 in PI cells that secrete DH44. Nf1 interacts genetically with peptide signaling to affect circadian behavior. We extended these studies to mammals to demonstrate that mouse astrocytes exhibit a 24-hr rhythm of calcium levels, which is also attenuated by lack of neurofibromin. These findings establish a conserved role for neurofibromin in intracellular signaling rhythms within the nervous system. : Bai et al. show that the gene mutated in the disease Neurofibromatosis 1 is required for maintaining levels or cycling of calcium in circadian neurons in Drosophila and in mammalian cells. These effects likely account for effects of Nf1 on circadian behavior in Drosophila and may be relevant in explaining sleep phenotypes in patients. Keywords: circadian rhythms, neurofibromatosis 1, Drosophila, peptide signaling, cycling of calcium, mouse astrocyte

Health Status and Permanent Loss to Follow up of Ellisras Longitudinal Study Subjects: Rural South African Context

Noncommunicable diseases (NCDs) are responsible for two out of three deaths worldwide with their profile changing from one country to another. But evidence to sustained these changes are still very limited in rural South African population. The well-characterized Ellisras Longitudinal Study (ELS) provides a unique opportunity of mapping some of these changes in vulnerable adolescent and young adults. The objective is we determined the extent of NCD risk factors derived from anthropometric and blood pressure measurements affected Ellisras Longitudinal Study (ELS) subjects over time for those who died or permanently lost to follow-up. A total of 2238 subjects aged 3–10 years (born between 1994 and 1986) were randomly selected to take part of the Ellisras Longitudinal Study (ELS) in November 1996. The attrition rate of ELS subjects based on death ranges between 0.71 and 3.73% for boys and 0.75 and 4.89% for girls. The prevalence of sever undernutrition ranges from 3.2 to 53%, moderate undernutrition ranges from 9.7 to 28.8%, while mild undernutrition ranges from 17.9 to 59.1% for both males and females. The prevalence of undernutrition was high while hypertension, obesity, and overweight were low in the population. The identification of appropriate NCD indicators for mortality in rural South African population needs more consideration and evaluation

An Optimal Linear Time Algorithm for Quasi-Monotonic Segmentation

Monotonicity is a simple yet significant qualitative characteristic. We consider the problem of segmenting a sequence in up to K segments. We want segments to be as monotonic as possible and to alternate signs. We propose a quality metric for this problem using the l_inf norm, and we present an optimal linear time algorithm based on novel formalism. Moreover, given a precomputation in time O(n log n) consisting of a labeling of all extrema, we compute any optimal segmentation in constant time. We compare experimentally its performance to two piecewise linear segmentation heuristics (top-down and bottom-up). We show that our algorithm is faster and more accurate. Applications include pattern recognition and qualitative modeling.Comment: This is the extended version of our ICDM'05 paper (arXiv:cs/0702142

Defining and distinguishing infant behavioral states using acoustic cry analysis: is colic painful?

BackgroundTo characterize acoustic features of an infant's cry and use machine learning to provide an objective measurement of behavioral state&nbsp;in a cry-translator. To apply the&nbsp;cry-translation algorithm to colic hypothesizing that these cries sound painful.MethodsAssessment of 1000 cries in a mobile app (ChatterBabyTM). Training a cry-translation&nbsp;algorithm by evaluating &gt;6000 acoustic features to predict whether infant cry was due to a pain (vaccinations, ear-piercings), fussy, or hunger states. Using the algorithm to predict the behavioral state of infants with reported colic.ResultsThe cry-translation&nbsp;algorithm was 90.7% accurate for identifying pain cries, and achieved 71.5% accuracy in discriminating cries from fussiness, hunger, or pain. The ChatterBaby&nbsp;cry-translation&nbsp;algorithm overwhelmingly predicted that colic cries were most likely from pain, compared to fussy and hungry states. Colic cries had average pain ratings of 73%, significantly greater than the pain measurements found in fussiness and hunger (p &lt; 0.001, 2-sample t test). Colic cries outranked pain cries by measures of acoustic intensity, including energy, length of voiced periods, and fundamental frequency/pitch, while fussy and hungry cries showed reduced intensity measures compared to pain and colic.ConclusionsAcoustic features of cries are consistent across a diverse infant population and can be utilized as objective markers of pain, hunger, and fussiness. The&nbsp;ChatterBaby algorithm detected significant acoustic similarities between colic and painful cries, suggesting that they may share a neuronal pathway

Stable ultrahigh-density magneto-optical recordings using introduced linear defects

The stability of data bits in magnetic recording media at ultrahigh densities is compromised by thermal `flips' -- magnetic spin reversals -- of nano-sized spin domains, which erase the stored information. Media that are magnetized perpendicular to the plane of the film, such as ultrathin cobalt films or multilayered structures, are more stable against thermal self-erasure than conventional memory devices. In this context, magneto-optical memories seem particularly promising for ultrahigh-density recording on portable disks, and bit densities of $\sim$100 Gbit inch$^{-2}$ have been demonstrated using recent advances in the bit writing and reading techniques. But the roughness and mobility of the magnetic domain walls prevents closer packing of the magnetic bits, and therefore presents a challenge to reaching even higher bit densities. Here we report that the strain imposed by a linear defect in a magnetic thin film can smooth rough domain walls over regions hundreds of micrometers in size, and halt their motion. A scaling analysis of this process, based on the generic physics of disorder-controlled elastic lines, points to a simple way by which magnetic media might be prepared that can store data at densities in excess of 1 Tbit inch$^{-2}$.Comment: 5 pages, 4 figures, see also an article in TRN News at http://www.trnmag.com/Stories/041801/Defects_boost_disc_capacity_041801.htm

Competition, predation, and migration: individual choice patterns of Serengeti migrants captured by hierarchical models

Large-herbivore migrations occur across gradients of food quality or food abundance that are generally determined by underlying geographic patterns in rainfall, elevation, or latitude, in turn causing variation in the degree of interspecific competition and the exposure to predators. However, the role of top-down effects of predation as opposed to the bottom-up effects of competition for resources in shaping migrations is not well understood. We studied 30 GPS radio-collared wildebeest and zebra migrating seasonally in the Serengeti-Mara ecosystem to ask how predation and food availability differentially affect the individual movement patterns of these co-migrating species. A hierarchical analysis of movement trajectories (directions and distances) in relation to grass biomass, high-quality food patches, and predation risk show that wildebeest tend to move in response to food quality, with little attention to predation risk. In contrast, individual zebra movements reflect a balance between the risk of predation and the access to high-quality food of sufficient biomass. Our analysis shows how two migratory species move in response to different attributes of the same landscape. Counterintuitively and in contrast to most other animal movement studies, we find that both species move farther each day when resources are locally abundant than when they are scarce. During the wet season when the quality of grazing is at its peak, both wildebeest and zebra move the greatest distances and do not settle in localized areas to graze for extended periods. We propose that this punctuated movement in highquality patches is explained by density dependency, whereby large groups of competing individuals (up to 1.65 million grazers) rapidly deplete the localized grazing opportunities. These findings capture the roles of predation and competition in shaping animal migrations, which are often claimed but rarely measured

Long-term effect of tocilizumab in patients with giant cell arteritis:open-label extension phase of the Giant Cell Arteritis Actemra (GiACTA) trial

Background: The combination of tocilizumab plus a glucocorticoid taper is effective in maintaining clinical remission without requiring additional glucocorticoid therapy in patients with giant cell arteritis, as shown in part one of the Giant Cell Arteritis Actemra (GiACTA) trial. However, the duration of the tocilizumab effect after discontinuation is unknown. Here, we explored the maintenance of efficacy 1 year after discontinuation of tocilizumab treatment, the effectiveness of retreatment with tocilizumab after relapse, and the long-term glucocorticoid-sparing effect of tocilizumab. Methods: In part one of the GiACTA trial, 251 patients were randomly assigned (2:1:1:1) to receive subcutaneous tocilizumab (162 mg) once a week or every other week, combined with a 26-week prednisone taper, or placebo combined with a prednisone taper over a period of either 26 weeks or 52 weeks. Patients in clinical remission stopped masked injections at 1 year (the conclusion of part one). In part two, treatment was at the investigators' discretion and could consist of no treatment, tocilizumab, glucocorticoids, methotrexate, or combinations of these, for two years. Maintenance of efficacy as assessed by clinical remission (defined as absence of relapse determined by the investigator), cumulative glucocorticoid dose, and long-term safety were exploratory objectives in part two of the trial. This trial is registered at ClinicalTrials.gov, NCT01791153. Findings: 215 patients participated in part two of the trial; 81 patients who were randomly assigned to tocilizumab once a week in part one were in clinical remission after 1 year, of whom 59 started part two on no treatment. 25 of these 59 patients (42%) maintained tocilizumab-free and glucocorticoid-free clinical remission throughout part two. Median (95% CI) cumulative glucocorticoid doses over 3 years were 2647 mg (1987\u20133507) for tocilizumab once a week, 3948 mg (2352\u20135186) for tocilizumab-every-other-week, 5277 mg (3944\u20136685) for placebo with a 26-week prednisone taper, and 5323 mg (3900\u20136951) for placebo with a 52-week prednisone taper (van Elteren p 640\ub7001, tocilizumab once a week vs placebo groups; p&lt;0\ub705, tocilizumab-every-other-week vs placebo groups). Tocilizumab-based regimens restored clinical remission among patients who experienced relapse in part two and were treated (median time to remission: 15 days for tocilizumab alone [n=17]; 16 days for tocilizumab plus glucocorticoids [n=36]; and 54 days for glucocorticoids alone [n=27]). No new or unexpected safety findings were reported over the full 3 years of the study. Interpretation: Giant cell arteritis remains a chronic disease that entails ongoing management and careful vigilance for disease relapse, but continuous indefinite treatment with immunosuppressive drugs is not required for all patients. A substantial proportion of patients treated with tocilizumab for one year maintain drug-free remission during the two years after tocilizumab cessation. For patients who experience relapse, tocilizumab can be used to manage relapses, but it remains prudent to include prednisone for patients who experience relapse because of the risk for vision loss. Funding: F Hoffmann-La Roche

Use of Cholecystokinin to Prevent the Development of Parenteral Nutritionâ Associated Cholestasis

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142290/1/jpen0100.pd