72 research outputs found
On the Lp-quantiles for the Student t distribution
L_p-quantiles represent an important class of generalised quantiles and are
defined as the minimisers of an expected asymmetric power function, see Chen
(1996). For p=1 and p=2 they correspond respectively to the quantiles and the
expectiles. In his paper Koenker (1993) showed that the tau quantile and the
tau expectile coincide for every tau in (0,1) for a class of rescaled Student t
distributions with two degrees of freedom. Here, we extend this result proving
that for the Student t distribution with p degrees of freedom, the tau quantile
and the tau L_p-quantile coincide for every tau in (0,1) and the same holds for
any affine transformation. Furthermore, we investigate the properties of
L_p-quantiles and provide recursive equations for the truncated moments of the
Student t distribution
Large deviations for risk measures in finite mixture models
Due to their heterogeneity, insurance risks can be properly described as a
mixture of different fixed models, where the weights assigned to each model may
be estimated empirically from a sample of available data. If a risk measure is
evaluated on the estimated mixture instead of the (unknown) true one, then it
is important to investigate the committed error. In this paper we study the
asymptotic behaviour of estimated risk measures, as the data sample size tends
to infinity, in the fashion of large deviations. We obtain large deviation
results by applying the contraction principle, and the rate functions are given
by a suitable variational formula; explicit expressions are available for
mixtures of two models. Finally, our results are applied to the most common
risk measures, namely the quantiles, the Expected Shortfall and the shortfall
risk measures
De Novo Assembly and Transcriptome Analysis of the Mediterranean Fruit Fly Ceratitis capitata Early Embryos
The agricultural pest Ceratitis capitata, also known as the Mediterranean fruit fly or Medfly, belongs to the Tephritidae family, which includes a large number of other damaging pest species. The Medfly has been the first non-drosophilid fly species which has been genetically transformed paving the way for designing genetic-based pest control strategies. Furthermore, it is an experimentally tractable model, in which transient and transgene-mediated RNAi have been successfully used. We applied Illumina sequencing to total RNA preparations of 8-10 hours old embryos of C. capitata, This developmental window corresponds to the blastoderm cellularization stage. In summary, we assembled 42,614 transcripts which cluster in 26,319 unique transcripts of which 11,045 correspond to protein coding genes; we identified several hundreds of long ncRNAs; we found an enrichment of transcripts encoding RNA binding proteins among the highly expressed transcripts, such as CcTRA-2, known to be necessary to establish and, most likely, to maintain female sex of C. capitata. Our study is the first de novo assembly performed for Ceratitis capitata based on Illumina NGS technology during embryogenesis and it adds novel data to the previously published C. capitata EST databases. We expect that it will be useful for a variety of applications such as gene cloning and phylogenetic analyses, as well as to advance genetic research and biotechnological applications in the Medfly and other related Tephritidae
Identification of sex determination genes and their evolution in Phlebotominae sand flies (Diptera, Nematocera)
Phlebotomine sand flies (Diptera, Nematocera) are important vectors of several pathogens, including Leishmania parasites, causing serious diseases of humans and dogs. Despite their importance as disease vectors, most aspects of sand fly biology remain unknown including the molecular basis of their reproduction and sex determination, aspects also relevant for the development of novel vector control strategies
Valutazione di Health Technology Assessment del sistema di sanificazione biologico a base di probiotici del genere Bacillus (PCHS)
Le infezioni correlate all’assistenza: priorità per la salute pubblica
Epidemiologia delle infezioni correlate all’assistenza in Italia e loro impatto per la salute pubblica
Sistemi di sanificazione attualmente disponibili in Italia
Il Probiotic Cleaning Hygiene System (PCHS): caratteristiche della tecnologia, aspetti di efficacia e sicurezza
Un sistema di sanificazione a base di probiotici per la riduzione delle infezioni correlate all’assistenza e la resistenza antimicrobica: analisi dell’impatto sul budget
Impatto ambientale per la salute pubblica degli attuali sistemi di sanificazione di ambienti/superfici in setting assistenziale e comunitario e potenziali benefici dei nuovi sistemi innovativi
Analisi delle principali raccomandazioni nazionali su sanificazione e disinfezione degli ambienti sanitari
Valutazione etica dell’utilizzo del Probiotic Cleaning Hygiene System (PCHS) in Italia
Elementi chiave per il processo decisional
De Novo assembly and transcriptome analysis of the mediterranean fruit fly ceratitis capitata early embryos
The agricultural pest Ceratitis capitata, also known as the Mediterranean fruit fly or Medfly, belongs to the Tephritidae family, which includes a large number of other damaging pest species. The Medfly has been the first non-drosophilid fly species which has been genetically transformed paving the way for designing geneticbased pest control strategies. Furthermore, it is an experimentally tractable model, in which transient and transgene-mediated RNAi have been successfully used. We applied Illumina sequencing to total RNA preparations of 8-10 hours old embryos of C. capitata, This developmental window corresponds to the blastoderm cellularization stage. In summary, we assembled 42,614 transcripts which cluster in 26,319 unique transcripts of which 11,045 correspond to protein coding genes; we identified several hundreds of long ncRNAs; we found an enrichment of transcripts encoding RNA binding proteins among the highly expressed transcripts, such as CcTRA-2, known to be necessary to establish and, most likely, to maintain female sex of C. capitata. Our study is the first de novo assembly performed for Ceratitis capitata based on Illumina NGS technology during embryogenesis and it adds novel data to the previously published C. capitata EST databases. We expect that it will be useful for a variety of applications such as gene cloning and phylogenetic analyses, as well as to advance genetic research and biotechnological applications in the Medfly and other related Tephritidae
How to produce male-only progeny in pest insects for SIT: a biotech approach.
Insects represent the most abundant group of animals on earth, comprising about
800,000 described species, and approximately 10,000 of these species can be
actually destructive for human activities. Pest control interventions, alternative to
pesticides, are increasingly being implemented within the concept of Integrated Pest
Management, involving the biological control to eradicate a pest from the area of
interest. This concept has been recently extended also to those hemathophagous
insects transmitting human diseases, such as for example mosquitoes.
The Sterile Insect Technique (SIT) is a species-specific and environmentally friendly
method for insect biological control, based on release of sterilized insects within
reasonable proximity of all native females to decrease the next progeny, due to the
reduced mating between their fertile wild counterparts. Release of insects of both
sexes is less effective than male-only release in reducing the wild population, while
removing females from the production and release procedures, would produce
considerable advantages in economic and effectiveness terms. Hence a genetic
sexing system to produce male-only progeny, would improve the effectiveness of SIT.
My PhD project has been focused on novel biotechnological approaches to control
insect species, such as the agricultural pest Ceratitis capitata (Diptera; Tephritidae)
and the mosquito disease vector Aedes aegypti (Diptera; Culicidae). The first part of
my Ph.D. experimental work has been focused on the molecular and functional
studies of the C. capitata transgenic strain Cc5.3, which is a first prototype of a novel
sexing system, based on masculinization of XX individuals. This strain can produce
male-only progeny in specific crosses, by a maternal transgene-mediated RNAi
against a key gene for female sex determination. The male only progeny obtained by
this method could be used, in future, for release programs in SIT, after sterilization.
I asked some questions to which I partially answered during my PhD thesis: 1) are
the XX males competitive in mating with wild type females? 2) is the masculinization
observed at phenotypic level, also fully penetrant at molecular level? 3) which are the
regulatory elements influencing the peculiar maternal effect in this transgenic strain?
Moreover, I have also investigated additional novel genes, such as Drosophila
orthologues of doa and fru genes, potentially involved in sex determination and
sexual differentiation of C. capitata (doa gene, a kinase involved in splicing control)
and Ae. aegypti (fru gene, a transcriptional factor involved in courtship behaviour)
which can be possible targets for novel transgene-mediated RNAi and hence the
development of improved sexing strains. Interestingly, I have found similar to
Drosophila, sex-biased isoforms of Ceratitis DOA encoding transcripts, which could
be involved in controlling sex-specific alternative splicing of target genes.
Furthermore I have contributed to clarify the molecular differences underlying the
sex-specific splicing of the fru gene in Aedes with the respect of other dipteran
species, proposing a model for sex determination in this mosquitoes species.
In addition to RNAi, novel reverse genetic tools are available. I've tested the TALENs'
action in Ae. aegypti and C. capitata and more recently the CRISP-CAS9 method in
Ceratitis
On the Lp-quantiles for the Student t distribution
Lp-quantiles are a class of generalised quantiles defined as the minimisers of an expected asymmetric power function. For p=1p=1 and p=2p=2 they correspond respectively to the quantiles and the expectiles. In this contribution we show that for the class of Student t distributions with p degrees of freedom, the Lp-quantile and the quantile coincide for any confidence level τ∈(0,1)τ∈(0,1). The proof involves concepts from combinatorial analysis as well as a recursive formula for the truncated moments of the Student t distribution. This work extends the contribution of Koenker (1993) that shows a similar result for the expectile
RNA-seq and Insect pests: new methods for the identification and the analysis of sex-specific genes in species of economic or sanitary interests.
Insects are among the largest taxonomic animal groups on Earth. In some cases, their interactions with humans can be harmful and the knowledge of the lifecycle of insect species, e.g. disease vectors and agricultural pests, opens new chances to develop eco-sustainable control strategies, alternative to pesticides. Reproduction and sex determination are at the same time crucial aspects to understand insect biology and optimal targets to limit their population growth and diffusion. We are applying RNA-seq and digital gene expression analysis to the study of sex determination in Insect species. In particular we are comparing de novo assembled transcriptomes of early sexed embryonic populations of the agricultural pest Ceratitis capitata (Diptera, Tephritidae) to identify the unknown primary signal of sex determination in this species. We are producing de novo transcriptomes from adult males and females of the two hematophagous dipteran non-model species Aedes albopictus (Diptera, Culicidae) and Phlebotomus perniciosus (Diptera, Psychodidae), to identify genes with sex-specific or sex-biased expression, potentially involved in sex determination pathway of these vector species. We are also developing new graphical interfaces and on-line databases for comparative genomic analyses and digital gene expression analyses in biological samples with opposite sexes
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