1,983 research outputs found
An Introduction to the Study of Gastrotricha, with a Taxonomic Key to Families and Genera of the Group
Gastrotricha is a group of meiofaunal-sized, free-living invertebrates present in all aquatic
ecosystems. The phylum includes over 860 species globally, of which 505 nominal species have
been recorded in marine sandy sediments; another 355 taxa inhabit the freshwater environments, where they are recurrent members of the periphyton and epibenthos, and, to a lesser degree, of the plankton and interstitial fauna. Gastrotrichs are part of the permanent meiofauna and, in general, they rank among the top five groups for abundance within meiobenthic assemblages. The diversity, abundance, and ubiquity of Gastrotricha allow us to suppose an important role for these animals in aquatic ecosystems; however, ecological studies to prove this idea have been comparatively very few. This is mainly because the small size and transparency of their bodies make gastrotrichs dicult to discover in benthic samples; moreover, their contractility and fragility make their handling and morphological survey of the specimens rather dicult. Here we oer an overview, describe the basic techniques used to study these animals, and provide a key to known genera in an attempt to promote easy identification and to increase the number of researchers who may be interested in conducting studies on this understudied ecological group of microscopic organisms
A broad spectrum of genomic changes in latinamerican patients with EXT1/EXT2-CDG
Multiple osteochondromatosis (MO), or EXT1/EXT2-CDG, is an autosomal dominant O-linked glycosylation disorder characterized by the formation of multiple cartilage-capped tumors (osteochondromas). In contrast, solitary osteochondroma (SO) is a non-hereditary condition. EXT1 and EXT2, are tumor suppressor genes that encode glycosyltransferases involved in heparan sulfate elongation. We present the clinical and molecular analysis of 33 unrelated Latin American patients (27 MO and 6 SO). Sixty-three percent of all MO cases presented severe phenotype and two malignant transformations to chondrosarcoma (7%). We found the mutant allele in 78% of MO patients. Ten mutations were novel. The disease-causing mutations remained unknown in 22% of the MO patients and in all SO patients. No second mutational hit was detected in the DNA of the secondary chondrosarcoma from a patient who carried a nonsense EXT1 mutation. Neither EXT1 nor EXT2 protein could be detected in this sample. This is the first Latin American research program on EXT1/EXT2-CDG.Fil: Delgado, M. A.. Universidad Nacional de Córdoba. Facultad de Medicina; ArgentinaFil: Martinez Domenech, G.. Universidad Nacional de Córdoba. Facultad de Medicina; ArgentinaFil: Sarrión, P.. Universidad de Barcelona; EspañaFil: Urreizti, R.. Universidad de Barcelona; EspañaFil: Zecchini, L.. Hospital de Niños de la Santísima Trinidad; ArgentinaFil: Robledo, H. H.. Hospital de Niños de la Santísima Trinidad; ArgentinaFil: Segura, F.. Universidad Nacional de Córdoba; ArgentinaFil: Dodelson de Kremer, Raquel. Universidad Nacional de Córdoba. Facultad de Medicina; ArgentinaFil: Balcells, S.. Universidad de Barcelona; EspañaFil: Grinberg, D.. Universidad de Barcelona; EspañaFil: Asteggiano, Carla Gabriela. Universidad Nacional de Córdoba. Facultad de Medicina. Centro de Est.de Las Metabolopatias Congenitas. Cátedra de Clinica Pediatrica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentin
A broad spectrum of genomic changes in Latinamerican patients with EXT1/EXT2-CDG
Multiple osteochondromatosis (MO), or EXT1/EXT2-CDG, is an autosomal dominant O-linked glycosylation disorder characterized by the formation of multiple cartilage-capped tumors (osteochondromas). In contrast, solitary osteochondroma (SO) is a non-hereditary condition. EXT1 and EXT2, are tumor suppressor genes that encode glycosyltransferases involved in heparan sulfate elongation. We present the clinical and molecular analysis of 33 unrelated Latin American patients (27 MO and 6 SO). Sixty-three percent of all MO cases presented severe phenotype and two malignant transformations to chondrosarcoma (7%). We found the mutant allele in 78% of MO patients. Ten mutations were novel. The disease-causing mutations remained unknown in 22% of the MO patients and in all SO patients. No second mutational hit was detected in the DNA of the secondary chondrosarcoma from a patient who carried a nonsense EXT1 mutation. Neither EXT1 nor EXT2 protein could be detected in this sample. This is the first Latin American research program on EXT1/EXT2-CDG
Coverage-based quality metric of mutation operators for test suite improvement
The choice of mutation operators is a fundamental aspect in mutation testing to guide the tester to an effective test suite. Designing a set of mutation operators is subject to a trade-off between effectiveness and computational cost: a larger mutation population might uncover more faults, but will take longer to analyse. With the aim of resolving this trade-off, several authors have defined an assortment of metrics to determine the most valuable operators. In this work, we extend an existing quality metric by incorporating an additional source of data and coverage information and therefore investigate the extent to which mutants that are often covered but rarely killed can improve the evaluation of mutation operators for the refinement of the test suite. As a case study, we analyse C++ class-level operators based on the new coverage-based quality metric to assess whether the original metric is enhanced. The results when selecting the best-valued operators show that this metric has great potential to help the tester in finding effective mutation operators. In comparison with the metric from which it is derived, the use of coverage data allows to reduce the number of mutants but often loses fewer test cases and, in addition, retains those that seem hard to design
Computer Vision and Metrics Learning for Hypothesis Testing: An Application of Q-Q Plot for Normality Test
This paper proposes a new procedure to construct test statistics for
hypothesis testing by computer vision and metrics learning. The application
highlighted in this paper is applying computer vision on Q-Q plot to construct
a new test statistic for normality test. Traditionally, there are two families
of approaches for verifying the probability distribution of a random variable.
Researchers either subjectively assess the Q-Q plot or objectively use a
mathematical formula, such as Kolmogorov-Smirnov test, to formally conduct a
normality test. Graphical assessment by human beings is not rigorous whereas
normality test statistics may not be accurate enough when the uniformly most
powerful test does not exist. It may take tens of years for statistician to
develop a new and more powerful test statistic. The first step of the proposed
method is to apply computer vision techniques, such as pre-trained ResNet, to
convert a Q-Q plot into a numerical vector. Next step is to apply metric
learning to find an appropriate distance function between a Q-Q plot and the
centroid of all Q-Q plots under the null hypothesis, which assumes the target
variable is normally distributed. This distance metric is the new test
statistic for normality test. Our experimentation results show that the
machine-learning-based test statistics can outperform traditional normality
tests in all cases, particularly when the sample size is small. This study
provides convincing evidence that the proposed method could objectively create
a powerful test statistic based on Q-Q plots and this method could be modified
to construct many more powerful test statistics for other applications in the
future
Physical and psychological paths toward less severe fibromyalgia: A structural equation model
The authors gratefully acknowledge all the participants for their
collaboration and enthusiasm. We thank the assistant researchers
involved in this study and all the members of the Physical Activity
for HEaLth Promotion (PA-HELP; CTS-1018) research group.Supplementary data associated with this article can be found, in
the online version, at https://doi.org/10.1016/j.rehab.2019.06.017.Objectives: Previous research suggested isolated associations of physical and psychological factors with
fibromyalgia severity. Integration of physical and psychological, experienced and observed, modifiable
factors associated with fibromyalgia severity in a single model will reveal therapeutic paths toward less
severity of disease. We aimed to examine an encompassing model of determinants of fibromyalgia
severity.
Methods: This observational, population-based cross-sectional study included 569 people with
fibromyalgia. An integrative model of fibromyalgia severity was tested by using structural equation
modelling. This model included 8 factors: resilience, catastrophizing, active lifestyle, declarative
memory, subjective fitness, objective fitness, psychological distress, and physical fatigue.
Results: Two core paths were associated with reduced fibromyalgia severity: 1) a psychological path
connecting high resilience and low catastrophizing with low distress and 2) a physical path, connecting a
more active lifestyle (directly and via high objective and subjective physical fitness) with low fatigue.
Additional interconnecting paths especially suggested a connection from the psychological to physical
path. Our model explained 83% of the fibromyalgia severity.
Conclusions: The present model integrated the complexity of mutually influencing factors of fibromyalgia
severity, which may help to better understand the disease. It emphasised the importance of: 1) physical
factors and psychological factors and their interconnections, 2) patients’ experiences and clinical
measurements, and 3) positive and negative signs such as physical fitness and distress. Future
longitudinal and experimental research should aim at testing the causal direction of the associations in
the model as well as the clinical implications suggested by the model. For instance, to reduce fatigue,
exercise should enhance not only objective fitness but also fitness-related perceptions. Reducing distress
and fatigue seems crucial for lowering fibromyalgia severity.This work was supported by the Spanish Ministry of Economy and Competitiveness [I+D+i DEP2010-15639, I+D+I DEP2013-40908, I+D+I PSI2015-65241-R, and BES-2014-067612] and the Spanish Ministry of Education [FPU15/00002]. This study was funded in part by the University of Granada, Plan Propio de Investigación 2016, Excellence actions: Units of Excellence; Unit of Excellence on Exercise and Health (UCEES), and the Junta de Andalucía, Consejería de Conocimiento, Investigación y Universidades and European Regional Development Fund (ref. SOMM17/6107/UGR) and University of Jaén, Plan de Apoyo a la Investigación 2017-2019 [EI_SEJ07_2017]. The funders did not have any role in the study design, data collection and analyses, decision to publish, or preparation of the manuscript
Acute febrile illness is associated with Rickettsia spp infection in dogs
BACKGROUND: Rickettsia conorii is transmitted by Rhipicephalus sanguineus ticks and causes Mediterranean Spotted Fever (MSF) in humans. Although dogs are considered the natural host of the vector, the clinical and epidemiological significance of R. conorii infection in dogs remains unclear. The aim of this prospective study was to investigate whether Rickettsia infection causes febrile illness in dogs living in areas endemic for human MSF. METHODS: Dogs from southern Italy with acute fever (n = 99) were compared with case–control dogs with normal body temperatures (n = 72). Serology and real-time PCR were performed for Rickettsia spp., Ehrlichia canis, Anaplasma phagocytophilum/A. platys and Leishmania infantum. Conventional PCR was performed for Babesia spp. and Hepatozoon spp. Acute and convalescent antibodies to R. conorii, E. canis and A. phagocytophilum were determined. RESULTS: The seroprevalence rates at first visit for R. conorii, E. canis, A. phagocytophilum and L. infantum were 44.8%, 48.5%, 37.8% and 17.6%, respectively. The seroconversion rates for R. conorii, E. canis and A. phagocytophilum were 20.7%, 14.3% and 8.8%, respectively. The molecular positive rates at first visit for Rickettsia spp., E. canis, A. phagocytophilum, A. platys, L. infantum, Babesia spp. and Hepatozoon spp. were 1.8%, 4.1%, 0%, 2.3%, 11.1%, 2.3% and 0.6%, respectively. Positive PCR for E. canis (7%), Rickettsia spp. (3%), Babesia spp. (4.0%) and Hepatozoon spp. (1.0%) were found only in febrile dogs. The DNA sequences obtained from Rickettsia and Babesia PCRs positive samples were 100% identical to the R. conorii and Babesia vogeli sequences in GenBank®, respectively. Febrile illness was statistically associated with acute and convalescent positive R. conorii antibodies, seroconversion to R. conorii, E. canis positive PCR, and positivity to any tick pathogen PCRs. Fourteen febrile dogs (31.8%) were diagnosed with Rickettsia spp. infection based on seroconversion and/or PCR while only six afebrile dogs (12.5%) seroconverted (P = 0.0248). The most common clinical findings of dogs with Rickettsia infection diagnosed by seroconversion and/or PCR were fever, myalgia, lameness, elevation of C-reactive protein, thrombocytopenia and hypoalbuminemia. CONCLUSIONS: This study demonstrates acute febrile illness associated with Rickettsia infection in dogs living in endemic areas of human MSF based on seroconversion alone or in combination with PCR
Quisquis: A new design for anonymous cryptocurrencies
Despite their usage of pseudonyms rather than persistent identifiers, most existing cryptocurrencies do not provide users with any meaningful levels of privacy. This has prompted the creation of privacy-enhanced cryptocurrencies such as Monero and Zcash, which are specifically designed to counteract the tracking analysis possible in currencies like Bitcoin. These cryptocurrencies, however, also suffer from some drawbacks: in both Monero and Zcash, the set of potential unspent coins is always growing, which means users cannot store a concise representation of the blockchain. Additionally, Zcash requires a common reference string and the fact that addresses are reused multiple times in Monero has led to attacks to its anonymity.
In this paper we propose a new design for anonymous cryptocurrencies, Quisquis, that achieves provably secure notions of anonymity. Quisquis stores a relatively small amount of data, does not require trusted setup, and in Quisquis each address appears on the blockchain at most twice: once when it is generated as output of a transaction, and once when it is spent as input to a transaction. Our result is achieved by combining a DDH-based tool (that we call updatable keys) with efficient zero-knowledge arguments
Family Literacy Practices and Parental Involvement of Latin American Immigrant Mothers
Fatigue in Women with Fibromyalgia: A Gene-Physical Activity Interaction Study
Fatigue is a cardinal symptom in fibromyalgia. Fatigue is assumed to be the result of genetic susceptibility and environmental factors. We aimed at examining the role of genetic susceptibility for fatigue in southern Spanish women with fibromyalgia, by looking at single nucleotide polymorphisms in 34 fibromyalgia candidate-genes, at the interactions between genes, and at the gene-physical activity interactions. We extracted DNA from saliva of 276 fibromyalgia women to analyze gene-polymorphisms. Accelerometers registered physical activity and sedentary behavior. Fatigue was assessed with the Multidimensional Fatigue Inventory. Based on the Bonferroni's and False Discovery Rate values, we found that the genotype of the rs4453709 polymorphism (sodium channel protein type 9 subunit alpha, SCN9A, gene) was related to reduced motivation (AT carriers showed the highest reduced motivation) and reduced activity (AA carriers showed the lowest reduced activity). Carriers of the heterozygous genotype of the rs1801133 (methylene tetrahydrofolate reductase, MTHFR, gene) or rs4597545 (SCN9A gene) polymorphisms who were physically active reported lower scores on fatigue compared to their inactive counterparts. Highly sedentary carriers of the homozygous genotype of the rs7607967 polymorphism (AA/GG genotype; SCN9A gene) presented more reduced activity (a dimension of fatigue) than those with lower levels of sedentary behavior. Collectively, findings from the present study suggest that the contribution of genetics and gene-physical activity interaction to fatigue in fibromyalgia is modest
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