196,670 research outputs found
Pricing Chinese rain: a multi-site multi-period equilibrium pricing model for rainfall derivatives
No full textMany industries are exposed to weather risk which they can transfer on financial markets via weather derivatives. Equilibrium models based on partial market clearing became a useful tool for pricing such kind of financial instruments. In a multi-period equilibrium pricing model agents rebalance their portfolio of weather bonds and a risk free asset in each period such that they maximize the expected utility of their incomes constituted by possibly weather dependent profits and payoffs of portfolio positions. We extend the model to a multisite version and apply it to pricing rainfall derivatives for Chinese provinces. By simulating realistic market conditions with two agent types, farmers with profits highly exposed to weather risk and a financial investor diversifying her financial portfolio, we obtain equilibrium prices for weather derivatives on cumulative monthly rainfall. Dynamic portfolio optimization under market clearing and utility indifference of these representative agents determines equilibrium quantity and price for rainfall derivatives.rainfall derivatives, equilibrium pricing, space-time Markov model
Difference based Ridge and Liu type Estimators in Semiparametric Regression Models
No full textWe consider a difference based ridge regression estimator and a Liu type estimator of the regression parameters in the partial linear semiparametric regression model, y = Xβ + f + ε. Both estimators are analysed and compared in the sense of mean-squared error. We consider the case of independent errors with equal variance and give conditions under which the proposed estimators are superior to the unbiased difference based estimation technique. We extend the results to account for heteroscedasticity and autocovariance in the error terms. Finally, we illustrate the performance of these estimators with an application to the determinants of electricity consumption in Germany.Difference based estimator; Differencing estimator, Differencing matrix, Liu estimator, Liu type estimator, Multicollinearity, Ridge regression estimator, Semiparametric model
An intrinsically safe facility for forefront research and training on nuclear technologies - Burnup and transmutation
No full textThe currently dominant open fuel cycles have resulted in the gradual accumulation of (relatively)
large quantities of highly radioactive or fertile materials in the form of depleted uranium, plutonium,
minor actinides (MA) and long-lived fission products (LLFP). For low-activity wastes a heavily shielded
surface repository is required. Spent fuel can be instead directly buried in deep geological repositories
or reprocessed in order to separate U and Pu and eventually also MA and LLFP from other materials.
These elements can be further burnt by modern reactors but not yet in sufficient quantities to slow down
the steady accumulation of these materials in storage. Using ADS, the residual long-lifetime isotopes can
be transmuted by nuclear reactions into shorter-lifetime isotopes again storable in surface repositories.
However, in order to perform transmutations at a practical level, high-power reactors (and consequently
high-power accelerators) are required; particularly, a significant transmutation can be reached not only
by increasing the beam current to something of the order of a few tens of mA, but also by increasing
the beam energy above 500MeV in order to reach the spallation regime. Such high-power infrastructures
require intermediate test facilities with lower power and higher safety level for the investigation of their
dynamics and transmutation capabilities: the ADS proposed in this study could accomplish many of these
constraints
A new fetal RHD genotyping test : costs and benefits of mass testing to target antenatal anti-D prophylaxis in England and Wales
No full textBackground
Postnatal and antenatal anti-D prophylaxis have dramatically reduced maternal sensitisations and cases of rhesus disease in babies born to women with RhD negative blood group. Recent scientific advances mean that non-invasive prenatal diagnosis (NIPD), based on the presence of cell-free fetal DNA in maternal plasma, could be used to target prophylaxis on "at risk" pregnancies where the fetus is RhD positive. This paper provides the first assessment of cost-effectiveness of NIPD-targeted prophylaxis compared to current policies.
Methods
We conducted an economic analysis of NIPD implementation in England and Wales. Two scenarios were considered. Scenario 1 assumed that NIPD will be only used to target antenatal prophylaxis with serology tests continuing to direct post-delivery prophylaxis. In Scenario 2, NIPD would also displace postnatal serology testing if an RhD negative fetus was identified. Costs were estimated from the provider's perspective for both scenarios together with a threshold royalty fee per test. Incremental costs were compared with clinical implications.
Results
The basic cost of an NIPD in-house test is £16.25 per sample (excluding royalty fee). The two-dose antenatal prophylaxis policy recommended by NICE is estimated to cost the NHS £3.37 million each year. The estimated threshold royalty fee is £2.18 and £8.83 for Scenarios 1 and 2 respectively. At a £2.00 royalty fee, mass NIPD testing would produce no saving for Scenario 1 and £507,154 per annum for Scenario 2. Incremental cost-effectiveness analysis indicates that, at a test sensitivity of 99.7% and this royalty fee, NIPD testing in Scenario 2 will generate one additional sensitisation for every £9,190 saved. If a single-dose prophylaxis policy were implemented nationally, as recently recommended by NICE, Scenario 2 savings would fall.
Conclusions
Currently, NIPD testing to target anti-D prophylaxis is unlikely to be sufficiently cost-effective to warrant its large scale introduction in England and Wales. Only minor savings are calculated and, balanced against this, the predicted increase in maternal sensitisations may be unacceptably high. Reliability of NIPD assays still needs to be demonstrated rigorously in different ethnic minority populations. First trimester testing is unlikely to alter this picture significantly although other emerging technologies may
Leading and higher twists in the proton polarized structure function g1p at large Bjorken x
No full textA phenomenological parametrization of the proton polarized structure function g1p(x,Q2) is developed for x≳0.02 using deep inelastic data up to ∼50 (GeV/c)2 as well as available experimental results on both photo- and electroproduction of proton resonances. According to the new parametrization the generalized Drell-Hearn-Gerasimov sum rule is predicted to have a zero-crossing point at Q2=0.16±0.04 (GeV/c)2. Then, low-order polarized Nachtmann moments are estimated and their Q2 behavior is investigated in terms of leading and higher twists for Q2≳1 (GeV/c)2. The leading twist is treated at NLO in the strong coupling constant and the effects of higher orders of the perturbative series are estimated using soft-gluon resummation techniques. In the case of the first moment, higher-twist effects are found to be quite small for Q2≳1 (GeV/c)2, and the singlet axial charge has been determined to be a0[10 (GeV/c)2]=0.16±0.09. In the case of higher order moments, which are sensitive to the large-x region, higher-twist effects are significantly reduced by the introduction of soft gluon contributions, but they are still relevant at Q2∼ few (GeV/c)2 at variance with the case of the unpolarized transverse structure function of the proton. Our finding suggests that spin-dependent correlations among partons may have more impact than spin-independent ones. As a by-product, it is also shown that the Bloom-Gilman local duality is strongly violated in the region of polarized electroproduction of the Δ(1232) resonance
sj-docx-1-smo-10.1177_20503121221074480 – Supplemental material for The early impact of the global lockdown on post-secondary students and staff: A global, descriptive study
No full textSupplemental material, sj-docx-1-smo-10.1177_20503121221074480 for The early impact of the global lockdown on post-secondary students and staff: A global, descriptive study by Behdin Nowrouzi-Kia, Leeza Osipenko, Parvin Eftekhar, Nasih Othman, Sultan Alotaibi, Alexandra M Schuster, Hae Sun Suh and Andrea Duncan in SAGE Open Medicine</p
The meaning of handicrafts of children aged 4 to 5 in development of the fine motor skills
No full textDarba temats: Rokdarbu nozīme 4 - 5 gadus vecu bērnu sīkās motorikas attīstībā. Balstoties uz aktualitātēm izglītībā, personisko pieredzi, tika izvēlēts Pētījuma mērķis: Pētīt rokdarbu nozīmi sīkās motorikas apguvē 4 – 5 gadus veciem bērniem. Darbs sastāv no trijām nodaļām ar apakšnodaļām. Darbā tika analizētas pedagogu un psihologu atziņas par sīkās pirkstu muskulatūras attīstību vidējā pirmsskolas vecumā. Tāpat tika skatīts jautājums par 4 – 5 gadus vecu bērnu psiholoģiskajām īpatnībām, attīstību. Tika izpētīti materiāli rokdarbu nodarbību plānošanai un izstrādātas rekomendācijas darbam ar 4 – 5 gadus veciem bērniem rokdarbu nodarbībās. Tika veikts pētījums. Pētījumā izmantotas daudzveidīgas metodes. Darba vadītāja ir mag. paed., lektore: Ineta Aizporiete Darbs balstās uz ārzemju (Gabbard C., Rodrigies L., Козырева E., Вавилова А.Jermakovas un c.), kā arī uz Latvijas pedagogu un psihologu (D.Lieģenieces, D.Dzinteres, Šternfeldes I, Vidneres M., Ozoliņas I., Aizporietes I., Volānes E., I.Šternfelde un c.) teorētiskajām atziņām par bērna sīkās pirkstu muskulatūras attīstību un rokdarbu nozīmi 4 – 5 gadus veca bērna personības izaugsmē. Praktiskajā daļā veikti pedagoģiskie novērojumi, skolotāju intervijas, iegūto rezultātu analīze. Kvalifikācijas darbs sastāv no trīs nodaļām, 43 lpp, 4 pielikumiem, 5 attēliem, 43 literatūras avotiem.The title of qualification paper is „ The meaning of handicrafts of children aged 4 to 5 in development of the fine motor skills.” The author of the paper is Santa Osipenko, a student of the part – time first level professional study programme „Preschool education teacher” within the Faculty of Pedagogy of Riga, University of Latvia. The supervisor: Mg.paed., lect. Ineta Aizporiete. The aim of the research paper: to research the importance of the fine motor skills education for children aged 4 to 5. The paper consists of two main parts: theoretical and practical part. The research consists of three divisions with subdivisions. During the research the information made by educators and psychologists about the fine motor skills development and psyshological characteristics of children aged 4 to 5. Materials about lessons of handicraft planning werw researched. Based on the research there were made recommendations for work with children aged 4 to 5 during handicrafts lessons. The research was made using different kinds of methods. The theoretical part is based on the theoretical findings of both the foreign (Gabbard C., Rodrigies L., Козырева E., Вавилова А. ) and the Latvian pedagogues and psychologists (V. Hibnere, V.Jonīte, D.Lieģiniece, D.Dzintere ,E. Volāne, I.Šternfelde) about the development of childrens. The practical part is based on pedagogical observations, interview of teachers and analysis of results. The qualification paper consists of 3 chapters, 43 pages, 5 illustrations, literature and information – latvian and english authors, russian authors - 43
Pointwise adaptive estimation for quantile regression
No full textA nonparametric procedure for quantile regression, or more generally nonparametric M-estimation, is proposed which is completely data-driven and adapts locally to the regularity of the regression function. This is achieved by considering in each point M-estimators over different local neighbourhoods and by a local model selection procedure based on sequential testing. Non-asymptotic risk bounds are obtained, which yield rate-optimality for large sample asymptotics under weak conditions. Simulations for different univariate median regression models show good finite sample properties, also in comparison to traditional methods. The approach is the basis for denoising CT scans in cancer research.M-estimation, median regression, robust estimation, local model selection, unsupervised learning, local bandwidth selection, median filter, Lepski procedure, minimax rate, image denoising
Measurements of the band gap of ThF_{4} by electron spectroscopy techniques
No full textWe present an experimental determination of the band gap of ThF_{4} performed by two different techniques. The first measurement was performed by combining x-ray photoemission spectroscopy and bremsstrahlung isochromat spectroscopy. The second measurement exploited the position of the inelastic threshold in reflection electron energy loss spectroscopy. Both measurements gave compatible values of the band gap, with the average ΔE=10.2(2)eV. This value was found to be in excellent agreement with theoretical calculations. The measured band gap is significantly larger than the ^{229m}Th excitation energy, making ThF_{4} a possible candidate material for a solid-state nuclear clock based on the vacuum ultraviolet γ decay
Dr. Duane M. Jackson, Morehouse College, July 2011
No full textThis video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer
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