1,058 research outputs found
Eco-friendly contro strategies against the asian tiger mosquito, Aedes albopictus (Diptera: Culicidae): repellency and toxic activity of plant essential oils and extracts.
The economic and health problems related to the Asian tiger mosquito, Aedes albopictus (Diptera: Culicidae), are due to its ectoparasitic behaviour and to the transmission of many diseases, particularly arbovirus and parasites. The difficulty to control the larval instars of A. albopictus, the reduced effectiveness and high environmental impact of adulticide treatments, highlight that the most effective solution to protect against A. albopictus is the use of repellent products for personal use such as DEET (N, N-diethyl-3-methylbenzamide). This compound showed a high repellent power in time but also some disadvantages including toxic effects on humans, especially on children and elderly. On this purpose, natural substances acting as repellent, such as plant essential oils and extracts, are considered very promising. Here we reported a critical review of our researches on repellence exerted by six different essential oils. The most effective essential oil was C. sativum. Furthermore, we discussed our research work conducted on ten essential oils tested as alternative larvicidal compounds. Following the dedicated WHO method, we proved that R. chalepensis EO was the most effective larvicidal among ten tested essential oils. Moreover, as regards to plant extracts, here we conducted bioassays to evaluate if the methanolic neem cake extract and its fractions of increasing polarity exhibit good mortality rates against A. albopictus larvae. We believe that the chance to use natural products such as essential oils and neem cake extracts, effective at lower doses when compared to synthetic products currently marketed, could be an advantageous alternative to build newer and safer mosquito control tools
Valutazione longitudinale a breve termine della quota di enfisema fumo-correlato: analisi della casistica dello studio ITALUNG-CT.
La realizzazione sperimentale di programmi di screening per la diagnosi precoce del tumore polmonare nei soggetti ad alto rischio con uso di CT a bassa dose, ha rappresentato l’opportunità di valutare longitudinalmente anche la quota di enfisema fumo-correlato rilevabile all’esame CT. E’ in questo scenario che si inserisce lo studio oggetto di questa tesi che, attingendo alla casistica del trial clinico ITALUNG CT, ha l’obiettivo di correlare e di valutare l’evoluzione a breve termine degli aspetti radiologici con le prove funzionali respiratorie e la capacità di diffusione alveolo capillare del CO e le variazioni dell’ abitudine al fumo durante il follow-up.
E’ stata valutata l’evoluzione dell’enfisema durante un periodo di follow-up di due anni su 284 soggetti arruolati nel braccio attivo dell’ITALUNG-CT, considerando i seguenti parametri radiologici: Volume polmonare totale, Relative Areas a -910, -950, -960 e 15th percentile; in 208 soggetti è stato possibile lo studio della relazione degli stessi parametri radiologici con la capacità di diffusione alveolo capillare del CO ed i seguenti parametri funzionali respiratori: FEV1, FVC, VC, FRC, PEF, FEV1/SVC, FEV1/FVC, RV, RV/TLC e TLC. Inoltre è stato studiato un modello predittivo di evolutività dell’enfisema, combinando l’aspetto funzionale con quello radiologico.
I risultati ottenuti sono parzialmente concordi con i dati presenti in lettera, orientando verso una progressione, sebbene lieve, dell’enfisema polmonare sia radiologicamente che funzionalmente.
Le variazioni dell’abitudine al fumo, ed in particolare la cessazione del fumo nel corso dei due anni di follow-up, sono risultate significativamente associate ad un decremento del 15th perc, indicativo di una riduzione della densità verosimilmente spiegabile con una consensuale riduzione di un processo infiammatorio acuto.
L’ulteriore sviluppo del lavoro ad oggi eseguito sarà mirato al superamento di alcuni aspetti metodologici in particolare legati alla quantizzazione dell’enfisema ed alla realizzazione di approfondimenti nelle analisi statistiche
Decrease of sexual organ reciprocity between heterostylous primrose species, with possible functional and evolutionary implications
Background and Aims Heterostyly is a floral polymorphism that has fascinated evolutionary biologists since Darwin's seminal studies on primroses. The main morphological characteristic of heterostyly is the reciprocal placement of anthers and stigmas in two distinct (distyly) floral morphs. Variation in the degree of intermorph sexual reciprocity is relatively common and known to affect patterns of pollen transfer within species. However, the partitioning of sexual organ reciprocity within and between closely related species remains unknown. This study aimed at testing whether intermorph sexual reciprocity differs within vs. between primrose species that hybridize in nature and whether the positions of sexual organs are correlated with other floral traits. Methods Six floral traits were measured in both floral morphs of 15 allopatric populations of Primula elatior, P. veris and P. vulgaris, and anther-stigma reciprocity was estimated within and between species. A combination of univariate and multivariate approaches was used to test whether positions of reproductive organs were less reciprocal between than within species, to assess correlations between sexual organ positions and other corolla traits, and to quantify differences between morphs and species. Key Results The three species were morphologically well differentiated in most floral traits, except that P. veris and P. vulgaris did not differ significantly in sexual organ positions. Overall, lower interspecific than intraspecific sexual organ reciprocity was detected. This decrease was marked between P. elatior and P. vulgaris, intermediate and variable between P. elatior and P. veris, but negligible between P. veris and P. vulgaris. Conclusions Differences in anther and stigma heights between the analysed primrose species were of the same magnitude or larger than intraspecific differences that altered pollen flow within other heterostylous systems. Therefore, it is possible to suggest that considerable reductions of sexual organ reciprocity between species may lower interspecific pollen flow, with potential effects on reproductive isolatio
A Genuine ‘Miteinander’: On Becoming a Team in an International Virtual Simulation Game
Megacities is a simulation game which uses the Internet as a transnational virtual space for developing intercultural competence, thereby fostering intercultural dialogue. The experience of over a hundred people of several nationalities in this simulation game is at the core of this study, which aims to understand how individuals succeed in creating a genuine ‘Miteinander’ despite language barriers, the constraints of virtual communication, and expected cultural differences. ‘Miteinander’ is a German word which combines the concept of collaboration with that of cohesion. The introduction of this term allows us to further clarify the focus of this investigation, which aims to observe how a diverse group becomes a team in an online environment. This study is a qualitative one and its corpus is composed of reflection sheets in which participants share the feelings, thoughts and perceptions they had before, during, and after their experience in the game Megacities. The analysis of the data revealed that participants had similar fears and perceptions, despite their diversity. Out of their reflections, an interplay of factors related to individual, social, and technical-organizational dimensions emerges. Two factors which have a particularly high impact on the process of building trust and creating culture are looked at in depth in this paper: language and the virtual setting of communication
Asymptotic Self-Similarity of Minimizers and Local Bounds in a Model of Shape-Memory Alloys
We prove that microstructures in shape-memory alloys have a self-similar refinement pattern close to austenite-martensite interfaces, working within the scalar Kohn-Müller model. The latter is based on nonlinear elasticity and includes a singular perturbation representing the energy of the interfaces between martensitic variants. Our results include the case of low-hysteresis materials in which one variant has a small volume fraction. Precisely, we prove asymptotic self-similarity in the sense of strong convergence of blow-ups around points at the austenite-martensite interface. Key ingredients in the proof are pointwise estimates and local energy bounds. This generalizes previous results by one of us to various boundary conditions, arbitrary rectangular domains, and arbitrary volume fractions of the martensitic variants, including the regime in which the energy scales as ε2/3\documentclass[12pt]{minimal}
\usepackage{amsmath}
\usepackage{wasysym}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{amsbsy}
\usepackage{mathrsfs}
\usepackage{upgreek}
\setlength{\oddsidemargin}{-69pt}
\begin{document}\end{document} as well as the one where the energy scales as ε1/2\documentclass[12pt]{minimal}
\usepackage{amsmath}
\usepackage{wasysym}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{amsbsy}
\usepackage{mathrsfs}
\usepackage{upgreek}
\setlength{\oddsidemargin}{-69pt}
\begin{document}\end{document}.Deutsche Forschungsgemeinschaft
http://dx.doi.org/10.13039/501100001659Humboldt-Universität zu Berlin (1034)Peer Reviewe
- …