380 research outputs found
Centre bow and wet-deck design for motion and load reductions in wave piercing catamarans at medium speed
For wave piercing catamarans, the centre bow length and tunnel clearance are important design factors for slamming, passenger comfort and deck diving. This experimental study determined the influence of centre bow (CB) and wet-deck geometry on their motions and loads at reduced speed using five configurations. A 2.5â
m hydroelastic segmented catamaran model was tested in regular head seas in wave heights equivalent to 2.7â
m, 4.0â
m and 5.4â
m at full scale. Higher wet-decks had higher vertical accelerations but reduced slamming loads. The greatest peak vertical CB loads ranged between 18â105% of the total hull weight. Regression models were obtained for the vertical loads and bending moments. A reduction of speed from 38 knots to 20 knots reduces the maximum slam loads by approximately 30% in regular waves. Considering both low and high speeds, the Short CB was found to be a consistent design for slamming reduction
Using Remote Monitoring And Machine Learning To Classify Slam Events Of Wave Piercing Catamarans
An onboard monitoring system can measure features such as stress cycles counts and provide warnings due to slamming. Considering current technology trends there is the opportunity of incorporating machine learning methods into monitoring systems. A hull monitoring system has been developed and installed on a 111 m wave piercing catamaran (Hull 091) to remotely monitor the ship kinematics and hull structural responses. Parallel to that, an existing dataset of a similar vessel (Hull 061) was analysed using unsupervised and supervised learning models; these were found to be beneficial for the classification of bow entry events according to key kinematic parameters. A comparison of different algorithms including linear support vector machines, naĂŻve Bayes and decision tree for the bow entry classification were conducted. In addition, using empirical probability distributions, the likelihood of wet-deck slamming was estimated given a vertical bow acceleration threshold of 1 in head seas, clustering the feature space with the approximate probabilities of 0.001, 0.030 and 0.25
Bipartite Anterior Extraperitoneal Teratoma: Evidence for the Embryological Origins of Teratomas?
Teratomas are thought to arise from totipotent primordial germ cells (PGCs) Dehner (1983) which may miss their target destination Moore and Persaud (1984). Teratomas can occur anywhere from the brain to the coccygeal area but are usually in the midline close to the embryological position of the gonadal ridges Bale (1984), Nguyen and Laberge (2000). We report a case of a bipartite anterior extraperitoneal teratoma. This is an unusual position for a teratoma, but one which may support the âmissed targetâ theory of embryology
Two-photon quantum walks in an elliptical direct-write waveguide array
Integrated optics provides an ideal test bed for the emulation of quantum
systems via continuous-time quantum walks. Here we study the evolution of
two-photon states in an elliptic array of waveguides. We characterise the
photonic chip via coherent-light tomography and use the results to predict
distinct differences between temporally indistinguishable and distinguishable
two-photon inputs which we then compare with experimental observations. Our
work highlights the feasibility for emulation of coherent quantum phenomena in
three-dimensional waveguide structures.Comment: 8 pages, 7 figure
The challenges of the expanded availability of genomic information: an agenda-setting paper
Rapid advances in microarray and sequencing technologies are making genotyping and genome sequencing more affordable and readily available. There is an expectation that genomic sequencing technologies improve personalized diagnosis and personalized drug therapy. Concurrently, provision of direct-to-consumer genetic testing by commercial providers has enabled individualsâ direct access to their genomic data. The expanded availability of genomic data is perceived as influencing the relationship between the various parties involved including healthcare professionals, researchers, patients, individuals, families, industry, and government. This results in a need to revisit their roles and responsibilities. In a 1-day agenda-setting meeting organized by the COST Action IS1303 âCitizenâs Health through public-private Initiatives: Public health, Market and Ethical perspectives,â participants discussed the main challenges associated with the expanded availability of genomic information, with a specific focus on public-private partnerships, and provided an outline from which to discuss in detail the identified challenges. This paper summarizes the points raised at this meeting in five main parts and highlights the key cross-cutting themes. In light of the increasing availability of genomic information, it is expected that this paper will provide timely direction for future research and policy making in this area.Funding Deborah Mascalzoni is supported under Grant Agreement number 305444. Ălvaro Mendes is supported by the FCTâThe Portuguese Foundation for Science and Technology under postdoctoral grant SFRH/BPD/88647/2012. Isabelle Budin-Ljøsne receives support from the National Research and Innovation Platform for Personalized Cancer Medicine funded by The Research Council of Norway (NFR BIOTEK2021/ES495029) and Biobank Norway funded by The Research Council of Norwayâgrant number 245464. Heidi Carmen Howard is partly supported by supported by the Swedish Foundation for Humanities and Social Science under grant M13-0260:1), the Biobanking and Molecular Resource Infrastructure of Sweden (BBMRI.se) and the BBMRI-ERIC. BrĂgida Riso is supported by the Portuguese Foundation for Science and Technology (FCT) under the PhD grant SFRH/BD/100779/2014. Heidi Beate Bentzen receives support from the project Legal Regulation of Information Processing relating to Personalized Cancer Medicine funded by The Research Council of Norway BIOTEK2021/238999
Nanometer-Scale Lateral pân Junctions in Graphene/Îą-RuCl<sub>3</sub> Heterostructures
The ability to create nanometer-scale lateral pân junctions is essential for the next generation of two-dimensional (2D) devices. Using the charge-transfer heterostructure graphene/Îą-RuCl3, we realize nanoscale lateral pân junctions in the vicinity of graphene nanobubbles. Our multipronged experimental approach incorporates scanning tunneling microscopy (STM) and spectroscopy (STS) and scattering-type scanning near-field optical microscopy (s-SNOM) to simultaneously probe the electronic and optical responses of nanobubble pân junctions. Our STM/STS results reveal that pân junctions with a band offset of âź0.6 eV can be achieved with widths of âź3 nm, giving rise to electric fields of order 108 V/m. Concurrent s-SNOM measurements validate a point-scatterer formalism for modeling the interaction of surface plasmon polaritons (SPPs) with nanobubbles. Ab initio density functional theory (DFT) calculations corroborate our experimental data and reveal the dependence of charge transfer on layer separation. Our study provides experimental and conceptual foundations for generating pân nanojunctions in 2D materials
SchrĂśdinger operators with δ and δâ˛-potentials supported on hypersurfaces
Self-adjoint SchrĂśdinger operators with δ and δâ˛-potentials supported on a smooth compact hypersurface are defined explicitly via boundary conditions. The spectral properties of these operators are investigated, regularity results on the functions in their domains are obtained, and analogues of the BirmanâSchwinger principle and a variant of Kreinâs formula are shown. Furthermore, Schattenâvon Neumann type estimates for the differences of the powers of the resolvents of the SchrĂśdinger operators with δ and δâ˛-potentials, and the SchrĂśdinger operator without a singular interaction are proved. An immediate consequence of these estimates is the existence and completeness of the wave operators of the corresponding scattering systems, as well as the unitary equivalence of the absolutely continuous parts of the singularly perturbed and unperturbed SchrĂśdinger operators. In the proofs of our main theorems we make use of abstract methods from extension theory of symmetric operators, some algebraic considerations and results on elliptic regularity
Increasing compliance with wearing a medical device in children with autism
Health professionals often recommend the use of medical devices to assess the health, monitor
the well-being, or improve the quality of life of their patients. Children with autism may present
challenges in these situations as their sensory peculiarities may increase refusals to wear such
devices. To address this issue, we systematically replicated prior research by examining the
effects of differential reinforcement of other behavior (DRO) to increase compliance with
wearing a heart rate monitor in 2 children with autism. The intervention increased compliance to
100% for both participants when an edible reinforcer was delivered every 90 s. The results
indicate that DRO does not require the implementation of extinction to increase compliance with
wearing a medical device. More research is needed to examine whether the reinforcement
schedule can be further thinned
Levels and Correlates of Non-Adherence to WHO Recommended Inter-Birth Intervals in Rufiji, Tanzania.
Poorly spaced pregnancies have been documented worldwide to result in adverse maternal and child health outcomes. The World Health Organization (WHO) recommends a minimum inter-birth interval of 33 months between two consecutive live births in order to reduce the risk of adverse maternal and child health outcomes. However, birth spacing practices in many developing countries, including Tanzania, remain scantly addressed. METHODS: Longitudinal data collected in the Rufiji Health and Demographic Surveillance System (HDSS) from January 1999 to December 2010 were analyzed to investigate birth spacing practices among women of childbearing age. The outcome variable, non-adherence to the minimum inter-birth interval, constituted all inter-birth intervals <33 months long. Inter-birth intervals >=33 months long were considered to be adherent to the recommendation. Chi-Square was used as a test of association between non-adherence and each of the explanatory variables. Factors affecting non-adherence were identified using a multilevel logistic model. Data analysis was conducted using STATA (11) statistical software. RESULTS: A total of 15,373 inter-birth intervals were recorded from 8,980 women aged 15--49 years in Rufiji district over the follow-up period of 11 years. The median inter-birth interval was 33.4 months. Of the 15,373 inter-birth intervals, 48.4% were below the WHO recommended minimum length of 33 months between two live births. Non-adherence was associated with younger maternal age, low maternal education, multiple births of the preceding pregnancy, non-health facility delivery of the preceding birth, being an in-migrant resident, multi-parity and being married. CONCLUSION: Generally, one in every two inter-birth intervals among 15--49 year-old women in Rufiji district is poorly spaced, with significant variations by socio-demographic and behavioral characteristics of mothers and newborns. Maternal, newborn and child health services should be improved with a special emphasis on community- and health facility-based optimum birth spacing education in order to enhance health outcomes of mothers and their babies, especially in rural settings
Geometric measure of quantum discord and the geometry of a class of two-qubit states
We investigate the geometric picture of the level surfaces of quantum
entanglement and geometric measure of quantum discord (GMQD) of a class of
X-states, respectively. This pictorial approach provides us a direct
understanding of the structure of entanglement and GMQD. The dynamic evolution
of GMQD under two typical kinds of quantum decoherence channels is also
investigated. It is shown that there exists a class of initial states for which
the GMQD is not destroyed by decoherence in a finite time interval.
Furthermore, we establish a factorization law between the initial and final
GMQD, which allows us to infer the evolution of entanglement under the
influences of the environment.Comment: 10 pages, 4 figures, comments are welcom
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