960 resultados para overlapping generations


Relevância:

20.00% 20.00%

Publicador:

Resumo:

A Kalman filter was developed for resolving overlapping lines in inductively coupled plasma atomic emission spectrometry (ICP-AES) and evaluated experimentally with the determination of La in the presence of Ho, and Cu in the presence of Pr. The whiteness of the innovation sequence for an optimal filter was explored to be the criterion for the correction of the wavelength positioning errors which may occur in spectral scans. Under the conditions of the medium-resolution spectrometer and 1.5 pm step size in scans, the filter effectively resolved the Cu/Pr line pair having a small peak separation of 4.8 pm. For the La/Ho line pair with a peak distance of 9.8 pm, an unbiased estimate for La concentration was still obtained even when the signal-to-background ratio was down to 0.048. Favourable detection limits for real samples were achieved. Unstructured backgrounds were modeled theoretically and all spectral scans therefore did not require the correction for solvent.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This paper tells the story of how a set of university lectures developed during the last six years. The idea is to show how (1) content, (2) communication and (3) assessment have evolved in steps which are named “generations of web learning”. The reader is offered a stepwise description of both didactic foundations of university lectures and practical implementation on a widely available web platform. The relative weight of directive elements has gradually decreased through the “three generations”, whereas characteristics of self-responsibility and self-guided learning have gained in importance. -Content was in early times presented and expected to be learned but in later phases expected to be constructed for examples of case studies. -Communication meant in early phases to deliver assignments to the lecturer but later on to form teams, exchange standpoints and review mutually. -Assessment initially consisted in marks invented and added up by the lecturer but was later enriched by peer review, mutual grading and voting procedures. How much “added value” can the web provide for teaching, training and learning? Six years of experience suggest: mainly insofar as new (collaborative and selfdirected) didactic scenarios are implemented! (DIPF/Orig.)

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Familial expansile osteolysis (FEO) is a rare disorder causing bone dysplasia. The clinical features of FEO include early-onset hearing loss, tooth destruction, and progressive lytic expansion within limb bones causing pain, fracture, and deformity. An 18-bp duplication in the first exon of the TNFRSF11A gene encoding RANK has been previously identified in four FEO pedigrees. Despite having the identical mutation, phenotypic variations among affected individuals of the same and different pedigrees were noted. Another 18-bp duplication, one base proximal to the duplication previously reported, was subsequently found in two unrelated FEO patients. Finally, mutations overlapping with the mutations found in the FEO pedigrees have been found in ESH and early-onset PDB pedigrees. An Iranian FEO pedigree that contains six affected individuals dispersed in three generations has previously been introduced; here, the clinical features of the proband are reported in greater detail, and the genetic defect of the pedigree is presented. Direct sequencing of the entire coding region and upstream and downstream noncoding regions of TNFRSF11A in her DNA revealed the same 18-bp duplication mutation as previously found in the four FEO pedigrees. Additionally, eight sequence variations as compared to the TNFRSF11A reference sequence were identified, and a haplotype linked to the mutation based on these variations was defined. Although the mutation in the Iranian and four of the previously described FEO pedigrees was the same, haplotypes based on the intragenic SNPs suggest that the mutations do not share a common descent.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Rather than treating conservative Protestantism as a homogenous phenomenon, recent literature has underlined the importance of disaggregating this group to illuminate important attitudinal and behavioral differences between conservative Protestants. However, the methods used to empirically operationalize conservative Protestantism have not always been able to capture variations within the groupings. Based on analysis of the 2004 Northern Ireland Life and Times Survey, we argue that religious self-identification is a more useful way of analyzing conservative Protestant subgroups than denomination or religious belief. We show that many of these identifications are overlapping, rather than stand-alone, religious group identifications. Moreover, the identification category of born-again has seldom been included in surveys. We find having a born-again identification to be a better predictor than the more frequently asked fundamentalist and evangelical categories of the religious and social beliefs that are seen as indicative of conservative Protestantism.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

We discuss the properties of the lifetime or the time-delay matrix Q(E) for multichannel scattering, which is related to the scattering matrix S(E) by Q = i?S(dS†/dE). For two overlapping resonances occurring at energies E with widths G(? = 1, 2), with an energy-independent background, only two eigenvalues of Q(E) are proved to be different from zero and to show typical avoided-crossing behaviour. These eigenvalues are expressible in terms of the four resonance parameters (E , G) and a parameter representing the strength of the interaction of the resonances. An example of the strong and weak interaction in an overlapping double resonance is presented for the positronium negative ion. When more than two resonances overlap (? = 1, ..., N), no simple representation of each eigenvalue has been found. However, the formula for the trace of the Q-matrix leads to the expression d(E) = -?arctan[(G/2)/(E - E)] + d(E) for the eigenphase sum d(E) and the background eigenphase sum d(E), in agreement with the known form of the state density. The formulae presented in this paper are useful in a parameter fitting of overlapping resonances. © 2006 IOP Publishing Ltd.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The development of methods providing reliable estimates of demographic parameters (e. g., survival rates, fecundity) for wild populations is essential to better understand the ecology and conservation requirements of individual species. A number of methods exist for estimating the demographics of stage-structured populations, but inherent mathematical complexity often limits their uptake by conservation practitioners. Estimating survival rates for pond-breeding amphibians is further complicated by their complex migratory and reproductive behaviours, often resulting in nonobservable states and successive cohorts of eggs and tadpoles. Here we used comprehensive data on 11 distinct breeding toad populations (Bufo calamita) to clarify and assess the suitability of a relatively simple method [the Kiritani-Nakasuji-Manly (KNM) method] to estimate the survival rates of stage-structured populations with overlapping life stages. The study shows that the KNM method is robust and provides realistic estimates of amphibian egg and larval survival rates for species in which breeding can occur as a single pulse or over a period of several weeks. The study also provides estimates of fecundity for seven distinct toad populations and indicates that it is essential to use reliable estimates of fecundity to limit the risk of under- or overestimating the survival rates when using the KNM method. Survival and fecundity rates for B. calamita populations were then used to define population matrices and make a limited exploration of their growth and viability. The findings of the study recently led to the implementation of practical conservation measures at the sites where populations were most vulnerable to extinction. © 2010 The Society of Population Ecology and Springer.