1,281 research outputs found

    SOME EARLY PORTUGUESE BILLS OF LADING, 1625-1708.

    Get PDF

    Digitally Continuous Multivalued Functions, Morphological Operations and Thinning Algorithms

    Get PDF
    In a recent paper (Escribano et al. in Discrete Geometry for Computer Imagery 2008. Lecture Notes in Computer Science, vol. 4992, pp. 81–92, 2008) we have introduced a notion of continuity in digital spaces which extends the usual notion of digital continuity. Our approach, which uses multivalued functions, provides a better framework to define topological notions, like retractions, in a far more realistic way than by using just single-valued digitally continuous functions. In this work we develop properties of this family of continuous functions, now concentrating on morphological operations and thinning algorithms. We show that our notion of continuity provides a suitable framework for the basic operations in mathematical morphology: erosion, dilation, closing, and opening. On the other hand, concerning thinning algorithms, we give conditions under which the existence of a retraction F:X⟶X∖D guarantees that D is deletable. The converse is not true, in general, although it is in certain particular important cases which are at the basis of many thinning algorithms

    Temporal Structure of Human Gaze Dynamics is Invariant During Free Viewing

    Get PDF
    We investigate the dynamic structure of human gaze and present an experimental study of the frequency components of the change in gaze position over time during free viewing of computer-generated fractal images. We show that changes in gaze position are scale-invariant in time with statistical properties that are characteristic of a random walk process. We quantify and track changes in the temporal structure using a well-defined scaling parameter called the Hurst exponent, H. We find H is robust regardless of the spatial complexity generated by the fractal images. In addition, we find the Hurst exponent is invariant across all participants, including those with distinct changes to higher order visual processes due to neural degeneration. The value we find for H of 0.57 shows that the gaze dynamics during free viewing of fractal images are consistent with a random walk process with persistent movements. Our research suggests the human visual system may have a common strategy that drives the dynamics of human gaze during exploration

    Ultrastructural morphology and cytochemistry of iron-deficient polymorphonuclear leukocytes

    Full text link
    Previous studies have documented decreased activities of certain enzymes and altered function in polymorphonuclear leukocytes (PMN) during iron deficiency. The present study was undertaken to determine if the enzymatic abnormalities could be correlated with morphologic or quantitative change in PMN granules. Ultrastructural examination of primary and secondary granules and assessment of the secondary granule components alkaline phosphatase and vicinal glycol-containing glycoconjugates was performed in rabbit bone marrow, peripheral blood, and peritoneal heterophils. In addition, biochemical quantifications of the secondary granule component alkaline phosphatase and the primary granule marker [beta]-glucuronidase were performed. The results confirmed that a marked, significant decrease in alkaline phosphatase occurs in iron-deficient animals; however, no biochemical decrease in [beta]-glucuronidase activity was observed. Ultrastructurally, PMN secondary granules of iron-deficient rabbits tended to be more numerous than in controls when examined with morphometric and glycoconjugate staining methods, but lacked staining in alkaline phosphatase preparations. These results demonstrate that iron-deficient rabbits produce normal to increased quantities of primary and secondary granules, despite a uniform deficiency of alkaline phosphatase, a secondary granule marker.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26267/1/0000352.pd

    Unhealthy food and beverage consumption during childhood and risk of cardiometabolic disease: a systematic review of prospective cohort studies

    Get PDF
    Background Global consumption of unhealthy foods, including ultra-processed foods (UPFs) and sugar-sweetened beverages (SSBs), has increased substantially among pediatric populations. Suboptimal diet during early life can track into adulthood, alongside risk factors for cardiometabolic disease. Objective To inform the development of updated WHO guiding principles for complementary feeding of infants and young children, this systematic review sought to examine the association between unhealthy food consumption during childhood and cardiometabolic risk biomarkers. Methods PubMed (Medline), EMBASE, and Cochrane CENTRAL were systematically searched, with no language restriction, up to 10 March 2022. Inclusion criteria were randomized controlled trials (RCTs), non-RCTs, and longitudinal cohort studies; children aged ≤10.9 y at exposure; studies reporting greater consumption of unhealthy foods and beverages (defined using nutrient- and food-based approaches) than no or low consumption; studies assessing critical nonanthropometric cardiometabolic disease risk outcomes (blood lipid profile, glycemic control, or blood pressure). Results Of 30,021 identified citations, 11 articles from 8 longitudinal cohort studies were included. Six studies focused on exposure to unhealthy foods or UPF, and 4 focused on SSB only. Methodological heterogeneity was too high across studies to meta-analyze effect estimates. A narrative synthesis of quantitative data revealed that exposure to unhealthy foods and beverages, specifically NOVA-defined UPF, in children of preschool age may be associated with a worse blood lipid and blood pressure profile in later childhood (Grading of Recommendations Assessment, Development, and Evaluation [GRADE]: low and very low certainty, respectively). No associations were evident between SSB consumption and blood lipids, glycemic control, or blood pressure (GRADE: all low certainty). Conclusions No definitive conclusion can be made because of quality of the data. More high-quality studies that purposefully assess the effects of unhealthy food and beverage exposure during childhood on cardiometabolic risk outcomes are needed. This protocol was registered at https://www.crd.york.ac.uk/PROSPERO/ as CRD42020218109

    Unhealthy food and beverage consumption in children and risk of overweight and obesity: a systematic review and meta-analysis

    Get PDF
    This WHO-commissioned review contributed to the update of complementary feeding recommendations, synthesizing evidence on effects of unhealthy food and beverage consumption in children on overweight and obesity. We searched PubMed (Medline), Cochrane CENTRAL and Embase for articles, irrespective of language or geography. Inclusion criteria were: 1) randomized controlled trials (RCTs); non-RCTs; cohort studies and pre/post studies with control; 2) participants ≤ 10.9 y at exposure; 3) studies reporting greater consumption of unhealthy foods/beverages vs. no or low consumption; 4) studies assessing anthropometric and/or body composition; and 5) publication date ≥ 1971. Unhealthy foods and beverages were defined using nutrient- and food-based approaches. Risk of bias was assessed using the ROBINS-I and RoB2 tools for non-randomized and randomized studies, respectively. Narrative synthesis was complemented by meta-analyses where appropriate. Certainty of evidence was assessed using GRADE. Of 26,542 identified citations, 60 studies from 71 articles were included. Most studies were observational (59/60), and no included studies were from low-income countries. The evidence base was low quality, as assessed by ROBINS-I and RoB2 tools. Evidence synthesis was limited by the different interventions and comparators across studies. Evidence indicated that consumption of sugar-sweetened beverages (SSB) and unhealthy foods in childhood may increase body mass index (BMI)/BMI z-score, % body fat or odds of overweight/obesity (low certainty of evidence). Artificially-sweetened beverages and 100% fruit juice consumption may make little/no difference to BMI, % body fat or overweight/obesity outcomes (low certainty of evidence). Meta-analyses of a subset of studies indicated a positive association between SSB intake and % body fat, but no association with change in BMI and BMI z-score. High-quality epidemiological studies that are designed to assess the effects of unhealthy food consumption during childhood on risk of overweight/obesity are needed to contribute to a more robust evidence base upon which to design policy recommendations. This protocol was registered at https://www.crd.york.ac.uk/PROSPERO as CRD42020218109

    Downregulation of exosomal miR-204-5p and miR-632 as a biomarker for FTD: a GENFI study

    Get PDF
    OBJECTIVE: To determine whether exosomal microRNAs (miRNAs) in cerebrospinal fluid (CSF) of patients with frontotemporal dementia (FTD) can serve as diagnostic biomarkers, we assessed miRNA expression in the Genetic Frontotemporal Dementia Initiative (GENFI) cohort and in sporadic FTD. METHODS: GENFI participants were either carriers of a pathogenic mutation in progranulin, chromosome 9 open reading frame 72 or microtubule-associated protein tau or were at risk of carrying a mutation because a first-degree relative was a known symptomatic mutation carrier. Exosomes were isolated from CSF of 23 presymptomatic and 15 symptomatic mutation carriers and 11 healthy non-mutation carriers. Expression of 752 miRNAs was measured using quantitative PCR (qPCR) arrays and validated by qPCR using individual primers. MiRNAs found differentially expressed in symptomatic compared with presymptomatic mutation carriers were further evaluated in a cohort of 17 patients with sporadic FTD, 13 patients with sporadic Alzheimer's disease (AD) and 10 healthy controls (HCs) of similar age. RESULTS: In the GENFI cohort, miR-204-5p and miR-632 were significantly decreased in symptomatic compared with presymptomatic mutation carriers. Decrease of miR-204-5p and miR-632 revealed receiver operator characteristics with an area of 0.89 (90% CI 0.79 to 0.98) and 0.81 (90% CI 0.68 to 0.93), respectively, and when combined an area of 0.93 (90% CI 0.87 to 0.99). In sporadic FTD, only miR-632 was significantly decreased compared with AD and HCs. Decrease of miR-632 revealed an area of 0.90 (90% CI 0.81 to 0.98). CONCLUSIONS: Exosomal miR-204-5p and miR-632 have potential as diagnostic biomarkers for genetic FTD and miR-632 also for sporadic FTD

    Identification of Radiopure Titanium for the LZ Dark Matter Experiment and Future Rare Event Searches

    Full text link
    The LUX-ZEPLIN (LZ) experiment will search for dark matter particle interactions with a detector containing a total of 10 tonnes of liquid xenon within a double-vessel cryostat. The large mass and proximity of the cryostat to the active detector volume demand the use of material with extremely low intrinsic radioactivity. We report on the radioassay campaign conducted to identify suitable metals, the determination of factors limiting radiopure production, and the selection of titanium for construction of the LZ cryostat and other detector components. This titanium has been measured with activities of 238^{238}Ue_{e}~<<1.6~mBq/kg, 238^{238}Ul_{l}~<<0.09~mBq/kg, 232^{232}The_{e}~=0.28±0.03=0.28\pm 0.03~mBq/kg, 232^{232}Thl_{l}~=0.25±0.02=0.25\pm 0.02~mBq/kg, 40^{40}K~<<0.54~mBq/kg, and 60^{60}Co~<<0.02~mBq/kg (68\% CL). Such low intrinsic activities, which are some of the lowest ever reported for titanium, enable its use for future dark matter and other rare event searches. Monte Carlo simulations have been performed to assess the expected background contribution from the LZ cryostat with this radioactivity. In 1,000 days of WIMP search exposure of a 5.6-tonne fiducial mass, the cryostat will contribute only a mean background of 0.160±0.0010.160\pm0.001(stat)±0.030\pm0.030(sys) counts.Comment: 13 pages, 3 figures, accepted for publication in Astroparticle Physic
    • …
    corecore