Aggregate Costs of Gender Gaps in the Labor Market: A Quantitative Estimate

This paper examines the quantitative effects of gender gaps in entrepreneurship and labor force participation on aggregate productivity and income per capita. We simulate an occupational choice model with heterogeneous agents in entrepreneurial ability, where agents choose to be workers, self-employed or employers. The model assumes that men and women have the same talent distribution, but we impose several frictions on women's opportunities and pay in the labor market. In particular, we restrict the fraction of women participating in the labor market.

Aggregate Costs of Gender Gaps in the Labor Market: A Quantitative Estimate

This paper examines the quantitative effects of gender gaps in entrepreneurship and labor force participation on aggregate productivity and income per capita. We simulate an occupational choice model with heterogeneous agents in entrepreneurial ability, where agents choose to be workers, self-employed or employers. The model assumes that men and women have the same talent distribution, but we impose several frictions on women's opportunities and pay in the labor market. In particular, we restrict the fraction of women participating in the labor market.

Stability of Citrus tristeza virus protective isolates in field conditions

The objective of this work was to monitor the maintenance of Citrus tristeza virus (CTV) protective isolates stability in selected clones of 'Pêra' sweet orange (Citrus sinensis), preimmunized or naturally infected by the virus, after successive clonal propagations. The work was carried out in field conditions in the north of Paraná State, Brazil. Coat protein gene (CPG) analysis of 33 isolates collected from 16 clones of 'Pêra' sweet orange was performed using single strand conformational polymorphism (SSCP). Initially, the isolates were characterized by symptoms of stem pitting observed in clones. Then viral genome was extracted and used as template for the amplification of CPG by reverse transcription polimerase chain reaction (RTPCR). RTPCR products electrophoretic profiles were analyzed using the Jaccard coefficient and the UPGMA method. The majority of the clones had weak to moderate stem pitting symptoms and its CTV isolates showed alterations in the SSCP profiles. However, the stability of the protective complex has been maintained, except for isolates from two analised clones. Low genetic variability was observed within the isolates during the studied years.

Statistical significance of quantitative PCR.

BACKGROUND: PCR has the potential to detect and precisely quantify specific DNA sequences, but it is not yet often used as a fully quantitative method. A number of data collection and processing strategies have been described for the implementation of quantitative PCR. However, they can be experimentally cumbersome, their relative performances have not been evaluated systematically, and they often remain poorly validated statistically and/or experimentally. In this study, we evaluated the performance of known methods, and compared them with newly developed data processing strategies in terms of resolution, precision and robustness. RESULTS: Our results indicate that simple methods that do not rely on the estimation of the efficiency of the PCR amplification may provide reproducible and sensitive data, but that they do not quantify DNA with precision. Other evaluated methods based on sigmoidal or exponential curve fitting were generally of both poor resolution and precision. A statistical analysis of the parameters that influence efficiency indicated that it depends mostly on the selected amplicon and to a lesser extent on the particular biological sample analyzed. Thus, we devised various strategies based on individual or averaged efficiency values, which were used to assess the regulated expression of several genes in response to a growth factor. CONCLUSION: Overall, qPCR data analysis methods differ significantly in their performance, and this analysis identifies methods that provide DNA quantification estimates of high precision, robustness and reliability. These methods allow reliable estimations of relative expression ratio of two-fold or higher, and our analysis provides an estimation of the number of biological samples that have to be analyzed to achieve a given precision.

Développement de l'interprétation quantitative de la sismique réflexion lacustre : application de l'AVO aux sédiments quaternaires dans le lac Léman

Résumé Des développements antérieurs, au sein de l'Institut de Géophysique de Lausanne, ont permis de développer des techniques d'acquisition sismique et de réaliser l'interprétation des données sismique 2D et 3D pour étudier la géologie de la région et notamment les différentes séquences sédimentaires du Lac Léman. Pour permettre un interprétation quantitative de la sismique en déterminant des paramètres physiques des sédiments la méthode AVO (Amplitude Versus Offset) a été appliquée. Deux campagnes sismiques lacustres, 2D et 3D, ont été acquises afin de tester la méthode AVO dans le Grand Lac sur les deltas des rivières. La géométrie d'acquisition a été repensée afin de pouvoir enregistrer les données à grands déports. Les flûtes sismiques, mises bout à bout, ont permis d'atteindre des angles d'incidence d'environ 40˚ . Des récepteurs GPS spécialement développés à cet effet, et disposés le long de la flûte, ont permis, après post-traitement des données, de déterminer la position de la flûte avec précision (± 0.5 m). L'étalonnage de nos hydrophones, réalisé dans une chambre anéchoïque, a permis de connaître leur réponse en amplitude en fonction de la fréquence. Une variation maximale de 10 dB a été mis en évidence entre les capteurs des flûtes et le signal de référence. Un traitement sismique dont l'amplitude a été conservée a été appliqué sur les données du lac. L'utilisation de l'algorithme en surface en consistante a permis de corriger les variations d'amplitude des tirs du canon à air. Les sections interceptes et gradients obtenues sur les deltas de l'Aubonne et de la Dranse ont permis de produire des cross-plots. Cette représentation permet de classer les anomalies d'amplitude en fonction du type de sédiments et de leur contenu potentiel en gaz. L'un des attributs qui peut être extrait des données 3D, est l'amplitude de la réflectivité d'une interface sismique. Ceci ajoute une composante quantitative à l'interprétation géologique d'une interface. Le fond d'eau sur le delta de l'Aubonne présente des anomalies en amplitude qui caractérisent les chenaux. L'inversion de l'équation de Zoeppritz par l'algorithme de Levenberg-Marquardt a été programmée afin d'extraire les paramètres physiques des sédiments sur ce delta. Une étude statistique des résultats de l'inversion permet de simuler la variation de l'amplitude en fonction du déport. On a obtenu un modèle dont la première couche est l'eau et dont la seconde est une couche pour laquelle V P = 1461 m∕s, ρ = 1182 kg∕m3 et V S = 383 m∕s. Abstract A system to record very high resolution (VHR) seismic data on lakes in 2D and 3D was developed at the Institute of Geophysics, University of Lausanne. Several seismic surveys carried out on Lake Geneva helped us to better understand the geology of the area and to identify sedimentary sequences. However, more sophisticated analysis of the data such as the AVO (Amplitude Versus Offset) method provides means of deciphering the detailed structure of the complex Quaternary sedimentary fill of the Lake Geneva trough. To study the physical parameters we applied the AVO method at some selected places of sediments. These areas are the Aubonne and Dranse River deltas where the configurations of the strata are relatively smooth and the discontinuities between them easy to pick. A specific layout was developed to acquire large incidence angle. 2D and 3D seismic data were acquired with streamers, deployed end to end, providing incidence angle up to 40˚ . One or more GPS antennas attached to the streamer enabled us to calculate individual hydrophone positions with an accuracy of 50 cm after post-processing of the navigation data. To ensure that our system provides correct amplitude information, our streamer sensors were calibrated in an anechoic chamber using a loudspeaker as a source. Amplitude variations between the each hydrophone were of the order of 10 dB. An amplitude correction for each hydrophone was computed and applied before processing. Amplitude preserving processing was then carried out. Intercept vs. gradient cross-plots enable us to determine that both geological discontinuities (lacustrine sediments/moraine and moraine/molasse) have well defined trends. A 3D volume collected on the Aubonne river delta was processed in order ro obtain AVO attributes. Quantitative interpretation using amplitude maps were produced and amplitude maps revealed high reflectivity in channels. Inversion of the water bottom of the Zoeppritz equation using the Levenberg-Marquadt algorithm was carried out to estimate V P , V S and ρ of sediments immediately under the lake bottom. Real-data inversion gave, under the water layer, a mud layer with V P = 1461 m∕s, ρ = 1182 kg∕m3 et V S = 383 m∕s.

Improved detection of Rhodococcus coprophilus with a new quantitative PCR assay.

Agricultural practices, such as spreading liquid manure or the utilisation of land as animal pastures, can result in faecal contamination of water resources. Rhodococcus coprophilus is used in microbial source tracking to indicate animal faecal contamination in water. Methods previously described for detecting of R. coprophilus in water were neither sensitive nor specific. Therefore, the aim of this study was to design and validate a new quantitative polymerase chain reaction (qPCR) to improve the detection of R. coprophilus in water. The new PCR assay was based on the R. coprophilus 16S rRNA gene. The validation showed that the new approach was specific and sensitive for deoxyribunucleic acid from target host species. Compared with other PCR assays tested in this study, the detection limit of the new qPCR was between 1 and 3 log lower. The method, including a filtration step, was further validated and successfully used in a field investigation in Switzerland. Our work demonstrated that the new detection method is sensitive and robust to detect R. coprophilus in surface and spring water. Compared with PCR assays that are available in the literature or to the culture-dependent method, the new molecular approach improves the detection of R. coprophilus.

The clinical use of quantitative ultrasound (QUS) in the detection and management of osteoporosis

For the detection and management of osteoporosis and osteoporosis-related fractures, quantitative ultrasound (QUS) is emerging as a relatively low-cost and readily accessible alternative to dual-energy X-ray absorptiometry (DXA) measurement of bone mineral density (BMD) in certain circumstances. The following is a brief, but thorough review of the existing literature with respect to the use of QUS in 6 settings: 1) assessing fragility fracture risk; 2) diagnosing osteoporosis; 3) initiating osteoporosis treatment; 4) monitoring osteoporosis treatment; 5) osteoporosis case finding; and 6) quality assurance and control. Many QUS devices exist that are quite different with respect to the parameters they measure and the strength of empirical evidence supporting their use. In general, heel QUS appears to be most tested and most effective. Overall, some, but not all, heel QUS devices are effective assessing fracture risk in some, but not all, populations, the evidence being strongest for Caucasian females over 55 years old. Otherwise, the evidence is fair with respect to certain devices allowing for the accurate diagnosis of likelihood of osteoporosis, and generally fair to poor in terms of QUS use when initiating or monitoring osteoporosis treatment. A reasonable protocol is proposed herein for case-finding purposes, which relies on a combined assessment of clinical risk factors (CR.F) and heel QUS. Finally, several recommendations are made for quality assurance and control.

Dietary n-6- or n-3-rich vegetable fats and antioxidants: effects on fatty acid composition and stability of rabbit plasma, liver and meat

We supplemented diets with a-tocopheryl acetate (100 mg/kg) and replaced beef tallow (BT) in feeds with increasing doses of n-6- or n-3-rich vegetable fat sources (linseed and sunflower oil), and studied the effects on the fatty acid (FA) composition, the a-tocopherol (aT) content and the oxidative stability of rabbit plasma and liver. These effects were compared with those observed in a previous study in rabbit meat. As in meat, the content of saturated, monounsaturated and trans FA in plasma and liver mainly reflected feed FA profile, except stearic acid in liver, which increased as feeds contained higher doses of vegetable fat, which could be related to an inhibition of the activity of the stearoyl-CoA-desaturase. As linseed oil increased in feeds, the n-6/n-3 FA ratio was decreased in plasma and liver as a result of the incorporation of FA from diets and also, due to the different performance and selectivity of desaturase enzymes. However, an increase in the dose of vegetable fat in feeds led to a significant reduction in the aT content of plasma and liver, which was greater when the fat source was linseed oil. Increasing the dose of vegetable fat in feeds also led to an increase in the susceptibility to oxidation (lipid hydroperoxide (LHP) value) of rabbit plasma, liver and meat and on the thiobarbituric acid (TBA) values of meat. Although the dietary supplementation with a-tocopheryl acetate increased the aT content in plasma and liver, it did not modify significantly their TBA or LHP values. In meat however, both TBA and LHP values were reduced by the dietary supplementation with a-tocopheryl acetate. The plasma aT content reflected the aT content in tissues, and correlated negatively with tissue oxidability. From the studied diets, those containing 1.5% linseed oil plus 1.5% BT and 100 mg of a-tocopheryl acetate/kg most improved the FA composition and the oxidative stability of rabbit tissues.

Rat PPARs: quantitative analysis in adult rat tissues and regulation in fasting and refeeding.

PPARs are members of the nuclear hormone receptor superfamily and are primarily involved in lipid metabolism. The expression patterns of all 3 PPAR isotypes in 22 adult rat organs were analyzed by a quantitative ribonuclease protection assay. The data obtained allowed comparison of the expression of each isotype to the others and provided new insight into the less studied PPAR beta (NR1C2) expression and function. This isotype shows a ubiquitous expression pattern and is the most abundant of the three PPARs in all analyzed tissues except adipose tissue. Its expression is especially high in the digestive tract, in addition to kidney, heart, diaphragm, and esophagus. After an overnight fast, PPAR beta mRNA levels are dramatically down-regulated in liver and kidney by up to 80% and are rapidly restored to control levels upon refeeding. This tight nutritional regulation is independent of the circulating glucocorticoid levels and the presence of PPAR alpha, whose activity is markedly up-regulated in the liver and small intestine during fasting. Finally, PPAR gamma 2 mRNA levels are decreased by 50% during fasting in both white and brown adipose tissue. In conclusion, fasting can strongly influence PPAR expression, but in only a few selected tissues.

Aggregate stability in soils cultivated with eucalyptus

The objective of this work was to evaluate the aggregate stability of tropical soils under eucalyptus plantation and native vegetation, and assess the relationships between aggregate stability and some soil chemical and physical properties. Argisols, Cambisol, Latosols and Plinthosol within three eucalyptus-cultivated regions, in the states of Espírito Santo, Rio Grande do Sul and Minas Gerais, Brazil, were studied. For each region, soils under native vegetation were compared to those under minimum tillage with eucalyptus cultivation. The aggregate stability was measured using the high-energy moisture characteristic (HEMC) technique, i.e., the moisture release curve at very low suctions. This method compares the resistance of aggregates to slaking on a relative scale from zero to one. Thus, the aggregate stability from different soils and management practices can be directly compared. The aggregate stability ratio was greater than 50% for all soils, which shows that the aggregate stability index is high, both in eucalyptus and native vegetation areas. This suggests that soil management adopted for eucalyptus cultivation does not substantially modify this property. In these soils, the aggregate stability ratio does not show a good relationship with clay or soil organic matter contents. However, soil organic matter shows a positive relationship with clay content and cation exchange capacity.

Biomechanical stability of a posterior-alone fixation technique after craniovertebral junction realignment.

OBJECTIVE: The aim of the current study was to investigate the biomechanical stability and fixation strength provided by a posterior approach reconstruction technique to realign the craniovertebral junction.¦METHODS: We tested seven human cadaver occipito-cervical spines (occiput-C4) by applying pure moments of ±1.5 Nm on a spine tester. Each specimen was tested in the following modes: 1) intact; 2) injured; 3) spacers alone at C1-C2 articulation (S); 4) spacers plus C1-C2 Posterior Instrumentation (S+PI); and 5) spacers plus C1-C2 posterior instrumentation plus midline wiring (S+PI+MLW). C1-C2 range of motion for each construct was obtained in flexion-extension, lateral bending, and axial rotation.¦RESULTS: In all the loading modes, S, S+PI, and S+PI+MLW constructs significantly reduced range of motion compared with the intact and injured condition (P < 0.05). There was no statistical difference between any of the three instrumentation constructs (P > 0.05).¦CONCLUSIONS: This study investigated the biomechanics of the posterior approach technique for realignment of the craniovertebral junction and also made comparisons with additional posterior fixations. The stand-alone spacers were stable in all three loading modes. Posterior instrumentation increased the stability as compared to stand-alone spacers. The third point of fixation, carried out by using midline wiring, increased the stability further. However, there was not much difference in the stability imparted with the midline wiring versus without. The present study highlights the biomechanics of this novel concept and reaffirms the view that distraction of the C1-C2 articular facets and direct articular joint atlantoaxial fixation would be an ideal method of management of basilar invagination.

Iowa Fen Rapid Assessment Method for Wetlands v. 1 Quantitative Rating, 2016

Rapid assessment methods are valuable tools for collecting information about the quality and status of natural systems. However, they are not a substitute for detailed surveys of those systems. Users of this method should consider that the method may under-score or over-score the site that’s assessed, especially when the site is not a typical fen (i.e. a sedge meadow could score lower than fens, but in-fact be a relatively high quality sedge meadow). This assessment can be used throughout most of the spring, summer and fall period, however the ideal “index period” would be from late May through early October when native plant communities, as well as invasive species, are most apparent.

Nonperturbative semiclassical stability of de Sitter spacetime for small metric deviations

We consider the linearized semiclassical Einstein equations for small deviations around de Sitter spacetime including the vacuum polarization effects of conformal fields. Employing the method of order reduction, we find the exact solutions for general metric perturbations (of scalar, vector and tensor type). Our exact (nonperturbative) solutions show clearly that in this case de Sitter is stable with respect to small metric deviations and a late-time attractor. Furthermore, they also reveal a breakdown of perturbative solutions for a sufficiently long evolution inside the horizon. Our results are valid for any conformal theory, even self-interacting ones with arbitrarily strong coupling.

Early Iron Age Pottery: A Quantitative Approach. Proceedings of the International Round Table organized by the Swiss School of Archaeology in Greece (Athens, Novembre 28-30, 2008).

Quantitative approaches in ceramology are gaining ground in excavation reports, archaeological publications and thematic studies. Hence, a wide variety of methods are being used depending on the researchers' theoretical premise, the type of material which is examined, the context of discovery and the questions that are addressed. The round table that took place in Athens on November 2008 was intended to offer the participants the opportunity to present a selection of case studies on the basis of which methodological approaches were discussed. The aim was to define a set of guidelines for quantification that would prove to be of use to all researchers. Contents: 1) Introduction (Samuel Verdan); 2) Isthmia and beyond. How can quantification help the analysis of EIA sanctuary deposits? (Catherine Morgan); 3) Approaching aspects of cult practice and ethnicity in Early Iron Age Ephesos using quantitative analysis of a Protogeometric deposit from the Artemision (Michael Kerschner); 4) Development of a ceramic cultic assemblage: Analyzing pottery from Late Helladic IIIC through Late Geometric Kalapodi (Ivonne Kaiser, Laura-Concetta Rizzotto, Sara Strack); 5) 'Erfahrungsbericht' of application of different quantitative methods at Kalapodi (Sara Strack); 6) The Early Iron Age sanctuary at Olympia: counting sherds from the Pelopion excavations (1987-1996) (Birgitta Eder); 7) L'aire du pilier des Rhodiens à Delphes: Essai de quantification du mobilier (Jean-Marc Luce); 8) A new approach in ceramic statistical analyses: Pit 13 on Xeropolis at Lefkandi (David A. Mitchell, Irene S. Lemos); 9) Households and workshops at Early Iron Age Oropos: A quantitative approach of the fine, wheel-made pottery (Vicky Vlachou); 10) Counting sherds at Sindos: Pottery consumption and construction of identities in the Iron Age (Stefanos Gimatzidis); 11) Analyse quantitative du mobilier céramique des fouilles de Xombourgo à Ténos et le cas des supports de caisson (Jean-Sébastien Gros); 12) Defining a typology of pottery from Gortyn: The material from a pottery workshop pit, (Emanuela Santaniello); 13) Quantification of ceramics from Early Iron Age tombs (Antonis Kotsonas); 14) Quantitative analysis of the pottery from the Early Iron Age necropolis of Tsikalario on Naxos (Xenia Charalambidou); 15) Finding the Early Iron Age in field survey: Two case studies from Boeotia and Magnesia (Vladimir Stissi); 16) Pottery quantification: Some guidelines (Samuel Verdan).