The maximum theoretical performance of unconcentrated solar photovoltaic and thermoelectric generator systems

The maximum efficiency for photovoltaic (PV) and thermoelectric generator (TEG) systems without concentration is investigated. Both a combined system where the TEG is mounted directly on the back of the PV and a tandem system where the incoming sunlight is split, and the short wavelength radiation is sent to the PV and the long wavelength to the TEG, are considered. An analytical model based on the Shockley-Queisser efficiency limit for PVs and the TEG figure of merit parameter $zT$ is presented. It is shown that for non-concentrated sunlight, even if the TEG operates at the Carnot efficiency and the PV performance is assumed independent of temperature, the maximum increase in efficiency is 4.5 percentage points (pp.) for the combined case and 1.8 pp. for the tandem case compared to a stand alone PV. For a more realistic case with a temperature dependent PV and a realistic TEG, the gain in performance is much lower. For the combined PV and TEG system it is shown that a minimum $zT$ value is needed in order for the system to be more efficient than a stand alone PV system.Comment: 6 pages, 5 figure

Smooth tail index estimation

Both parametric distribution functions appearing in extreme value theory - the generalized extreme value distribution and the generalized Pareto distribution - have log-concave densities if the extreme value index gamma is in [-1,0]. Replacing the order statistics in tail index estimators by their corresponding quantiles from the distribution function that is based on the estimated log-concave density leads to novel smooth quantile and tail index estimators. These new estimators aim at estimating the tail index especially in small samples. Acting as a smoother of the empirical distribution function, the log-concave distribution function estimator reduces estimation variability to a much greater extent than it introduces bias. As a consequence, Monte Carlo simulations demonstrate that the smoothed version of the estimators are well superior to their non-smoothed counterparts, in terms of mean squared error.Comment: 17 pages, 5 figures. Slightly changed Pickand's estimator, added some more introduction and discussio

Coagglutination and Enzyme Capture Tests for Detection of \u3ci\u3eEscherichia coli\u3c/i\u3e β-Galactosidase, β-Glucuronidase, and Glutamate Decarboxylase

Polyclonal antibodies to Escherichia coli β-galactosidase, β-glucuronidase, and glutamate decarboxylase were used in coagglutination tests for identification of these three enzymes in cell lysates. Enzyme capture assays were also developed for the detection of E. coli β-galactosidase and β-glucuronidase. The enzymes were released by using a gentle lysis procedure that did not interfere with antibody-enzyme interactions. All three enzymes were detected in 93% (51 of 55) of the E. coli strains tested by coagglutination; two of the three enzymes were identified in the remaining 7%. Of 42 non-E. coli tested by coagglutination, only four nonspecifically agglutinated either two or three of the anti-enzyme conjugates. Thirty-two (76%) non-E. coli isolates were negative by coagglutination for all three enzymes. The enzyme capture assay detected the presence of β-galactosidase in seven of eight and β-glucuronidase in all eight strains of E. coli tested. Some strains of β-galactosidase-positive Citrobacterfreundii and Enterobacter cloacae were also positive by the enzyme capture assay, indicating that the antibodies were not entirely specific for E. coli β-galactosidase; however, five other gas-positive non-E. coli isolates were negative by the enzyme capture assay. The coagglutination tests and enzyme capture assays were rapid and sensitive methods for the detection of E. coli ,β-galactosidase, β-glucuronidase, and glutamate decarboxylase

Coagglutination and Enzyme Capture Tests for Detection of \u3ci\u3eEscherichia coli\u3c/i\u3e β-Galactosidase, β-Glucuronidase, and Glutamate Decarboxylase

Polyclonal antibodies to Escherichia coli β-galactosidase, β-glucuronidase, and glutamate decarboxylase were used in coagglutination tests for identification of these three enzymes in cell lysates. Enzyme capture assays were also developed for the detection of E. coli β-galactosidase and β-glucuronidase. The enzymes were released by using a gentle lysis procedure that did not interfere with antibody-enzyme interactions. All three enzymes were detected in 93% (51 of 55) of the E. coli strains tested by coagglutination; two of the three enzymes were identified in the remaining 7%. Of 42 non-E. coli tested by coagglutination, only four nonspecifically agglutinated either two or three of the anti-enzyme conjugates. Thirty-two (76%) non-E. coli isolates were negative by coagglutination for all three enzymes. The enzyme capture assay detected the presence of β-galactosidase in seven of eight and β-glucuronidase in all eight strains of E. coli tested. Some strains of β-galactosidase-positive Citrobacterfreundii and Enterobacter cloacae were also positive by the enzyme capture assay, indicating that the antibodies were not entirely specific for E. coli β-galactosidase; however, five other gas-positive non-E. coli isolates were negative by the enzyme capture assay. The coagglutination tests and enzyme capture assays were rapid and sensitive methods for the detection of E. coli ,β-galactosidase, β-glucuronidase, and glutamate decarboxylase

Detection of \u3cem\u3eStrongylus vulgaris\u3c/em\u3e in Equine Faecal Samples by Real-Time PCR and Larval Culture – Method Comparison and Occurrence Assessment

Background: Strongylus vulgaris has become a rare parasite in Germany during the past 50 years due to the practice of frequent prophylactic anthelmintic therapy. To date, the emerging development of resistance in Cyathostominae and Parascaris spp. to numerous equine anthelmintics has changed deworming management and the frequency of anthelmintic usage. In this regard, reliable detection of parasitic infections, especially of the highly pathogenic S. vulgaris is essential. In the current study, two diagnostic methods for the detection of infections with S. vulgaris were compared and information on the occurrence of this parasite in German horses was gained. For this purpose, faecal samples of 501 horses were screened for S. vulgaris with real-time PCR and an additional larval culture was performed in samples of 278 horses. A subset of 26 horses underwent multiple follow-up examinations with both methods in order to evaluate both the persistence of S. vulgaris infections and the reproducibility of each diagnostic method. Results: The real-time PCR revealed S. vulgaris-DNA in ten of 501 investigated equine samples (1.9%). The larval culture demonstrated larvae of S. vulgaris in three of the 278 samples (1.1%). A direct comparison of the two methods was possible in 321 samples including 43 follow-up examinations with the result of 11 S. vulgaris-positive samples by real-time PCR and 4 S. vulgaris-positive samples by larval culture. The McNemar’s test (p-value = 0.016) revealed a significant difference and the kappa values (0.525) showed a moderate agreement between real-time PCR and larval culture. Conclusions: The real-time PCR detected a significantly higher proportion of positives of S. vulgaris compared to larval culture and should thus be considered as a routine diagnostic method for the detection of S. vulgaris in equine samples

Ferromagnetic ordering in dilute magnetic dielectrics with and without free carriers

The state of art in the theoretical and experimental studies of transition metal doped oxides (dilute magnetic dielectrics) is reviewed. The available data show that the generic non-equilibrium state of oxide films doped with magnetic impurities may either favor ferromagnetism with high Curie temperature or result in highly inhomogeneous state without long-range magnetic order. In both case concomitant defects (vacancies, interstitial ions play crucial part.Comment: 10 pages, 3 figures. The paper was presented at the Moscow Internation Symposium on Magnetism (MISM-08). To be published in Journ. Magnetism and Magnetic Material

Efficient method for site-directed mutagenesis in large plasmids without subcloning

Commonly used methods for site-directed DNA mutagenesis require copying the entire target plasmid. These methods allow relatively easy modification of DNA sequences in small plasmids but become less efficient and faithful for large plasmids, necessitating full sequence verification. Introduction of mutations in larger plasmids requires subcloning, a slow and labor-intensive process, especially for multiple mutations. We have developed an efficient DNA mutagenesis technique, UnRestricted Mutagenesis and Cloning (URMAC) that replaces subcloning steps with quick biochemical reactions. URMAC does not suffer from plasmid size constraints and allows simultaneous introduction of multiple mutations. URMAC involves manipulation of only the mutagenesis target site(s), not the entire plasmid being mutagenized, therefore only partial sequence verification is required. Basic URMAC requires two PCR reactions, each followed by a ligation reaction to circularize the product, with an optional third enrichment PCR step followed by a traditional cloning step that requires two restriction sites. Here, we demonstrate URMAC's speed, accuracy, and efficiency through several examples, creating insertions, deletions or substitutions in plasmids ranging from 2.6 kb to 17 kb without subcloning