AN IMPROVED MASS-REARING METHOD OF THE CARROT RUST FLY, PSILA ROSAE (DIPTERA: PSILIDAE)

Protein fed to adults of the carrot rust fly, Psila rosae F., enhanced oviposition: the addition of yeast hydrolysate to the sugar diet resulted in a 50% increase in oviposition, giving an average of 75 eggs per female.A description is given of a simple oviposition device, which allows normal oviposition (compared with sand).Carrots planted in sand gave best rearing results when inoculated with eggs 14 days after insertion. Germinating carrot seeds placed on top of the sand improved the rate of development of the eggs to pupae from 40% to 62

Missing values: sparse inverse covariance estimation andanextension to sparse regression

We propose an ℓ 1-regularized likelihood method for estimating the inverse covariance matrix in the high-dimensional multivariate normal model in presence of missing data. Our method is based on the assumption that the data are missing at random (MAR) which entails also the completely missing at random case. The implementation of the method is non-trivial as the observed negative log-likelihood generally is a complicated and non-convex function. We propose an efficient EM algorithm for optimization with provable numerical convergence properties. Furthermore, we extend the methodology to handle missing values in a sparse regression context. We demonstrate both methods on simulated and real dat

Glucosinolates on the leaf surface perceived by insect herbivores: review of ambiguous results and new investigations

Herbivorous insects identify their host plants either by structural features, chemical cues, or a combination. Some insects probe the host leaf prior feeding or oviposition, other species use olfactorial cues or compounds somewhere on the surface. Insects attacking Brassicaceae are no exception, some are attracted and stimulated by volatile isothiocyanates (ITC), many others depend fully on the non-volatile glucosinolates (GS) for host-plant recognition and acceptance. Since most insects have no access to the leaf interior investigators concluded that GS must be present on the leaf surface and ITC in the headspace. However, peelings of mechanically removed surface waxes were devoid of measurable amounts of GS, whereas solvent surface extractions revealed a correlation between stomatal conditions and GS concentrations. Both observations lead to the conclusion that the presence of GS on the top leaf surface is rather unlikely. In the experimental part we show that a chloroform/methanol/water (2:1:1 vol/vol/vol) solvent leaf extract contains GS and, in addition, thia-triaza-fluorenes (TTF), other oviposition stimulants of the cabbage root fly, Delia radicum. Electrophysiological investigations showed that both, GS and TTF stimulated specific receptor neurones of the fly. We suggest that these compounds probably originated from deeper leaf layers and that herbivorous insects may penetrate the wax layer and perceive the stimulating compounds in deeper layers or through the stomat

Mutterglück ab 40 – Primi- und Multiparae im Vergleich : Einfluss der Parität auf prä- und perinatale Komplikationen bei Frauen ab 40 Jahren

Darstellung des Themas: Die meisten Studien gehen davon aus, dass die geburtshilflichen Risiken bei Frauen ab 40 Jahren klinisch relevant zunehmen. Ein Alter ab 40 Jahren ist aber nicht primär als Risikofaktor anzusehen. In diesem Kontext kommt der Parität eine grosse Bedeutung zu. Fragestellung: Welche signifikanten prä- und perinatalen Komplikationen treten bei Primiparae im Alter ab 40 Jahren im Vergleich zu Multiparae im Alter ab 40 Jahren auf? Methode: Die Fragestellung der Bachelorarbeit wird mittels eines Literaturreviews im EMED-Format bearbeitet. Die Literatur setzt sich aus einer Recherche im NebisKatalog sowie Fachdatenbankrecherchen zusammen. Zur Evaluation der Studien wird das Arbeitsinstrument für ein Critical Appraisal (AICA) nach Ris und PreusseBleuler (2015) verwendet. Relevante Ergebnisse: Ein Alter ab 40 Jahren hat in den meisten Fällen Einfluss auf das Vorkommen von prä- und perinatalen Komplikationen. Primiparae ab 40 Jahren haben häufiger eine Plazenta praevia, eine Sectio caesarea, ein tiefes Geburtsgewicht oder eine Frühgeburt als Multiparae ab 40 Jahren. Auf folgende Komplikationen hat die Parität keinen Einfluss: Gestationsdiabetes, Hypertonie, postpartale Hämorrhagie, Makrosomie und intrauteriner Fruchttod. Schlussfolgerung: Der Einfluss der Parität auf prä- und perinatale Komplikationen bei Frauen ab 40 Jahren konnte teilweise bestätigt werden. Um genaue Aussagen darüber zu treffen, muss weitergehende Forschung betrieben werde

Secondary metabolites of the leaf surface affected by sulphur fertilisationand perceived by the diamondback moth

Summary.: Summary. Oilseed rape, Brassica napus L. (cv Express), plants were grown under three different sulphur regimes: sulphur-free (S0), normal sulphur (Sn, normal field concentration) and a sulphur-rich (S+, 2 × concentration of Sn). We performed dual choice oviposition assays with the diamondback moth, Plutella xylostella, using real plants and, for the first time with this insect, artificial leaves sprayed with methanolic leaf-surface extracts. The results mirrored those of a separate study of preferences for whole plants. Females laid more eggs on surrogate leaves that were treated with Sn extracts than on S0 plants, while only a slight, not significant, difference was observed between extracts of normal and sulphur-rich plants. This shows that chemical compounds on the leaf surface mediate the oviposition preference and that the female insect can perceive the quality of the host-plants in terms of their fertilisation status. Since leaf volatiles are known to be oviposition stimulants, we investigated the effects of leaf-surface extracts on insect olfactory responses using electroantennograms (EAGs). In agreement with the behavioural data, we found that extracts of sulphur-treated plants yielded higher EAG amplitudes than the S0 extracts. Since the leaf content of the volatiles isothiocyanates is influenced by sulphur nutrition, we analysed the extracts for these compounds. Above the detection threshold of our GC-MS system, no isothiocyanates were found. Thus, other compounds present in the surface extracts must be perceived by the antenna. However, the HPLC analysis revealed 11 different glucosinolates. Progoitrin (2-Hydroxy-3-butenyl) and gluconapoleiferin (2-Hydroxy-4-pentenyl), which belong to the hydroxy-alkene class of glucosinolates, were the most abundant compounds. The total glucosinolate content sharply increased from S0 to Sn plants, whereas it was slightly lower in n versus S+ plants. Since it is known that glucosinolates can stimulate oviposition, it seems likely that the increased content we observed was influencing the insect preference in this study to

Secondary metabolites of the leaf surface affected by sulphur fertilisationand perceived by the cabbage root fly

Summary.: Surrogate leaves treated with methanolic leaf surface extracts of Brassica napus L. (cv Express) plants that received three different sulphur fertilisation treatments showed even more marked differences by the oviposition choice of Delia radicum L. than the potted plants. This confirms that the oviposition preference of D. radicum is mediated by chemical compounds on the leaf surface and that the quality of host-plants in terms of their nutrition status can be perceived by the female insect. The oviposition data were positively correlated with the content of fractionated surface extracts containing either CIF ("cabbage identification factor”; 1,2-dehydro-3-thia- 4,10,10b-triaza-cyclopenta[.a.]fluorine-1-carboxylic acid) or glucosinolates. Electrophysiological recordings from the tarsal chemoreceptor sensilla C5 and D3,4 showed that receptor neurons react to glucosinolate- and CIF-fractions. We found that the chemosensory activity of specific glucosinolate- and CIF-receptor neurons corresponded with the respective behavioural activity in the oviposition choice assays. The responses of D. radicum to glucosinolates in the electrophysiological recordings studies corresponded to the observed oviposition preference on plants or artificial leaves characterised with an higher amount of glucosinolates on leave surfaces. The presented data suggested that CIF and glucosinolates are involved in host-plant preference of D. radicum and are perceived by tarsal chemoreceptor

L1-Penalization for Mixture Regression Models

We consider a finite mixture of regressions (FMR) model for high-dimensional inhomogeneous data where the number of covariates may be much larger than sample size. We propose an l1-penalized maximum likelihood estimator in an appropriate parameterization. This kind of estimation belongs to a class of problems where optimization and theory for non-convex functions is needed. This distinguishes itself very clearly from high-dimensional estimation with convex loss- or objective functions, as for example with the Lasso in linear or generalized linear models. Mixture models represent a prime and important example where non-convexity arises. For FMR models, we develop an efficient EM algorithm for numerical optimization with provable convergence properties. Our penalized estimator is numerically better posed (e.g., boundedness of the criterion function) than unpenalized maximum likelihood estimation, and it allows for effective statistical regularization including variable selection. We also present some asymptotic theory and oracle inequalities: due to non-convexity of the negative log-likelihood function, different mathematical arguments are needed than for problems with convex losses. Finally, we apply the new method to both simulated and real data.Comment: This is the author's version of the work (published as a discussion paper in TEST, 2010, Volume 19, 209--285). The final publication is available at http://www.springerlink.co