41 |
L'incidenza del diritto comunitario sulle convenzioni contro la doppia imposizioneNocete Correa, Francisco Josè <1980> 30 March 2007 (has links)
El sometimiento de una determinada manifestación de riqueza a más de una
soberanía tributaria estatal constituye uno de los principales problemas que perjudican
la movilidad de los factores productivos, distorsionando las relaciones comerciales que
pueden establecerse entre operadores económicos que se encuentran situados en países
diversos.
Conscientes del carácter negativo que esta circunstancia puede representar
para el desarrollo de sus relaciones económicas, e incluso políticas, con otros Estados,
las autoridades nacionales han procedido a la fijación de ciertas reglas que tienen por
finalidad establecer un reparto de la potestad impositiva correspondiente a una concreta
manifestación de riqueza entre las soberanías tributarias concurrentes, determinando el
sometimiento a gravamen en un único Estado o, en caso de que ninguna de las
soberanías tributarias concurrentes renuncie a su consideración, articulando las
medidas que permitan eliminar o atenuar el doble gravamen que se generaría.
Hallándonos en un contexto internacional, la adopción de estas reglas no
podía realizarse sino de una forma consensuada entre los sujetos soberanos que
constituyen esta sociedad, sin admitir mayores ingerencias que las derivadas de las
propias limitaciones establecidas para cada uno de los Estados contratantes en sus
propias normas constitucionales y de la aceptación de los condicionantes que pudiera
imponer el respeto al Derecho internacional.
Así fue como los convenios de doble imposición internacional, que
esencialmente revisten carácter bilateral, se convirtieron en el principal instrumento de
los Estados para luchar contra este fenómeno, complementándose con las medidas
unilaterales de carácter interno que cada uno de estos países adoptaba para perfeccionar
y hacer efectiva la regulación contenida en los mismos.
Sin embargo, la creación de la Comunidad Europea, con sus especiales
características, ha supuesto la aparición de un nuevo nivel de normatividad que afecta a
sus Estados miembros, imponiéndoles unas obligaciones que vienen a sumarse a las
que estos mismos Estados hayan asumido en su calidad de actores de la sociedad internacional y que, en determinadas circunstancias, pueden resultar contradictorias,
determinando el surgimiento de situaciones conflictivas entre instrumentos jurídicos
que pertenecen a diversos planos de normatividad y presentan un diverso ámbito de
aplicación.
Este trabajo pretende abordar una especie concreta perteneciente al género
de las situaciones conflictivas que pueden establecerse entre el Derecho comunitario y
las normas internacionales, concretamente las relativas a las contradicciones existentes
entre las normas pertenecientes al primero de los sistemas jurídicos mencionados y los
convenios de doble imposición suscritos por los Estados miembros de la Unión
Europea. No obstante, con carácter previo, consideramos oportuno abordar la
problemática reseñada desde una perspectiva general, aspecto al que dedicamos el
primer capítulo de nuestro trabajo, pues sólo una correcta determinación de las pautas
que rigen las relaciones entre los sistemas normativos a los que nos vamos a referir,
puede aportarnos el sustrato teórico necesario para afrontar nuestro particular estudio.
Una vez establecidas esas reglas de alcance general, abordaremos la primera
fase de nuestro estudio relativo a la incidencia del Derecho comunitario sobre los
convenios de doble imposición, tratando de determinar el alcance de las limitaciones
que las normas comunitarias originarias imponen a los Estados miembros al proceder a
la eliminación de la doble imposición mediante normas convencionales, intentando
identificar los aspectos de los convenios de doble imposición que presentan un carácter
más problemático con las exigencias comunitarias.
Esta labor de descubrimiento y depuración de los aspectos conflictivos de
los convenios de doble imposición, a la que dedicamos el segundo capítulo de nuestro
trabajo, se ha desarrollado por el Tribunal de Luxemburgo a través de una
interpretación expansiva del contenido de las libertades comunitarias que recibe la
denominación de “armonización negativa”, en función del carácter esencialmente
destructivo que ha representado para los instrumentos normativos utilizados por los
Estados miembros en la eliminación de la doble imposición.
En una segunda fase de nuestro análisis, a la que dedicamos el tercer
capítulo de nuestro estudio, intentaremos exponer el alcance que en materia de
eliminación de la doble imposición pueden presentar las medidas de carácter positivo adoptadas por las Instituciones comunitarias, así como la incidencia de las mismas
respecto a los convenios de doble imposición, tratando de clarificar cuál es el marco
competencial existente sobre esta materia e intentando señalar cuáles serían las
medidas más idóneas para resolver las situaciones conflictivas que pueden plantearse
entre el Derecho comunitario y los convenios de doble imposición.
La importancia que la eliminación de las situaciones de doble imposición
reviste en un contexto que, como el comunitario, ha reconocido la necesidad de
eliminar todas las trabas que perjudiquen la libre circulación de personas, capitales,
bienes y servicios, así como la inadecuación a las exigencias comunitarias de algunas
de las medidas que actualmente se ocupan de resolver esta cuestión, son aspectos que,
en nuestra opinión, justifican la realización del estudio que nos disponemos a
desarrollar.
|
42 |
Utilizzo del virus del rachitismo cespuglioso del pomodoro (TBSV) come vettore virale per l’induzione di resistenza al virus della vaiolatura delle drupacee (PPV)Pignatta, Daniela <1979> 18 May 2007 (has links)
No description available.
|
43 |
Studio dei meccanismi molecolari coinvolti nel determinismo sintomatologico di piante infette da virus e virus-satellitiContaldo, Nicoletta <1978> 06 June 2008 (has links)
The aim of our work was to study the molecular
mechanisms involved in symptoms appearance of plants
inoculated either with a virus or with a virus-satellite
complex.
In the first case, we tried to set up a reliable method for an
early identification of PVYNTN strains present in Italy and
causing potato tuber necrosis. This, to prevent their spread
in the field and to avoid severe yield losses, especially in
seed potato production. We tried to localize the particular
genomic region responsible for tuber necrosis. To this
purpose, we carried out RT-PCR experiments using various
primer combinations, covering PVY genomic regions larger
than those previously used by other authors. As the previous
researchers, though, we were not able to differentiate all
NTN from others PVY strains. This probably because of the
frequent virus variability, due to both genomic mutations
and possible recombination events among different strains.
In the second case, we studied the influence of Y-sat
(CaRNA5 satellite) on symptoms of CMV (Cucumber
mosaic virus) in Nicotiana benthamiana plants: strong
yellowing appearance instead of simple mosaic.
Wang et al (2004), inoculating the same infectious complex
on tobacco plants transformed with a viral suppressor of
plant silencing (HC-PRO), did not experience the
occurrence of yellowing anymore and, therefore,
hypotesized that changes in symptoms were due to plant
post transcriptional gene silencing (PTGS) mechanism. In
our case, inoculation of N. benthamiana plants transformed
with another PTGS viral suppressor (p19), and other plants
defective for RNA polymerase 6 (involved in systemic
silencing), still resulted in yellowing appearance. This, to
our opinion, suggests that in our system another possible
mechanism is involved.
|
44 |
Variazione dei markers di attivata coagulazione indotta dalla terapia infusionale con Infliximab in pazienti affetti da malattie infiammatorie croniche intestinaliSpina, Luisa <1975> 23 June 2008 (has links)
INTRODUCTION: A relationship between inflammatory response and coagulation is suggested by many observations. In particular, pro-inflammatory cytokines, such as TNFalpha, promote the activation of coagulation and reduce the production of anticoagulant molecules. It is known that inflammatory bowel diseases show a prothrombotic state and a condition of hypercoagulability. Aim of our study was to evaluate whether anti-TNFalpha therapy induces changes in the levels of coagulation activation markers in IBD patients. MATERIALS AND METHODS: We analyzed 48 plasma samples obtained before and 1 hour after 24 infliximab infusions (5 mg/kg) in 9 IBD patients (5 men and 4 women; mean age: 47.6+17.6 years; 4 Crohn's disease, 4 Ulcerative Colitis,1 Indeterminate Colitis). F1+2 and D-dymer levels were measured in each sample using ELISA methods.The data were statistically analyzed by means of Wilcoxon matched paired test. RESULTS: Median F1+2 levels were markdely reduced 1 hour after anti-TNFα infusion (median pre-infusion levels were 247.0 pmol/L and median post-infusion levels were 185.3 pmol/L) (p<0.002). Median D-dymer levels were also significantly reduced, from 485.2 ng/mL to 427.6 ng/mL (p< 0.001). These modifications were more evident in patients naive for infliximab therapy (p<0.02 for F1+2 and p<0.02 for D-dymer) and in Crohn's disease compared with Ulcerative Colitis patients (p=0.01 for F1+2 and p<0.007 for D-dymer).CONCLUSIONS: Infusion of infliximab significantly reduces the activation of coagulation cascade in IBD patients. This effect is early enough to suggest a direct effect of infliximab on the coagulation cascade and a possible new anti-inflammatory mechanism of action of this molecule.
|
45 |
Ruolo del tessuto adiposo nelle malattie infiammatorie croniche intestinali: valutazione dei livelli sierici di adipocitochine in pazienti affetti da colite ulcerosa e malattia di Crohn in terapia con InfliximabRondonotti, Emanuele <1974> 23 June 2008 (has links)
No description available.
|
46 |
Aiuti di Stato e coerenza dei sistemi tributari tra non discriminazione, libertà economiche e territorialitàMameli, Giovanni <1976> 28 February 2008 (has links)
No description available.
|
47 |
Imposta sul valore aggiunto e servizi finanziari: profili comunitari e nazionaliMontanari, Francesco <1976> 28 February 2008 (has links)
No description available.
|
48 |
La decadenza nei procedimenti tributari: profili nazionali e comunitariSanz Clavijo, Alfonso <1978> 14 March 2008 (has links)
No description available.
|
49 |
La cessazione dell'attività economica nell'IVA: profili nazionali e comunitariAddarii, Eleonora <1980> 27 June 2008 (has links)
La ricerca oggetto della tesi dottorale verte sulla ricostruzione della disciplina della
cessazione e delle fasi liquidatore dell’attività nell’ambito dell’imposta sul valore
aggiunto, nel tentativo di individuare criteri certi ed omogenei per la sua individuazione,
sia in prospettiva comunitaria che in prospettiva nazionale.
In primo luogo, l’indagine si concentra sulla ricostruzione della nozione di attività
economica e sui profili dinamici dell’attività in ambito comunitario, nell’intento di
chiarire, sulla base della giurisprudenza, i criteri utilizzati per individuare la cessazione
dell’attività rilevante ai fini dell’imposta, sfruttando in tal senso l’esperienza degli atti
preparatori e l’applicabilità dell’ipotesi di applicazione dell’imposta per autoconsumo
Vengono così valorizzati, accanto al profilo oggettivo costituito dalla presenza di una
legame tra le operazioni della fase liquidatoria, il ruolo del soggetto passivo, quale
portatore di una volontà che è in grado di influire sull’esistenza dell’attività stessa, e,
conseguentemente, delle dichiarazioni formali imposte dalla Direttiva, quale
manifestazione diretta di tale volontà ed elemento in grado di costituire un indice certo
di cessazione.
In seguito si esamina il regime impositivo nazionale ed in particolare le linee
interpretative maggioritarie accolte da dottrina e giurisprudenza. Ricostruiti nozione e
ruolo di attività economica, con riferimento all’esercizio d’impresa, vengono analizzati i
diversi casi di cessazione contemplati dall’ordinamento –liquidazione volontaria,
trasferimento dell’azienda e fallimento- analizzati sia nella prospettiva del diritto
tributario che in quella del diritto commerciale.
L’esame così sviluppato è volto a contestare l’interpretazione maggioritaria che vede
nella sola presenza di beni residui alla liquidazione, o comunque la permanenza di un
insieme di beni potenzialmente in grado di far riprendere l’esercizio, elemento
sufficiente a mantenere in vita l’impresa e con essa la soggettività passiva all’imposta.
Infine, vengono confrontati i risultati raggiunti nell’esame della disciplina comunitaria
nazionale, ponendone in evidenza le possibilità incompatibilità ed i punti di contatto,
con l’intenzione di dimostrare l’applicabilità anche a livello nazionale dei principi
emersi in ambito comunitario.
|
50 |
Produzione di virus sintetici per lo studio dei meccanismi di interazione coinvolti nell'induzione di resistenzaBianchi, Laura <1979> 11 April 2008 (has links)
Beet soil-borne mosaic virus (BSBMV) and Beet necrotic yellow vein virus
(BNYVV) are members of Benyvirus genus. BSBMV has been reported only in
the United States while BNYVV has a worldwide distribution. Both viruses are
vectored by Polymyxa betae, possess similar host ranges, particles number and
morphology. Both viruses are not serologically related but have similar genomic
organizations. Field isolates consist of four RNA species but some BNYVV
isolates contain a fifth RNA. RNAs 1 and 2 are essential for infection and
replication while RNAs 3 and 4 play important roles on plant and vector
interactions, respectively. Nucleotide and amino acid analyses revealed BSBMV
and BNYVV are different enough to be classified in two different species.
Additionally in BNYVV/BSBMV mixed infections, a competition was
previous described in sugar beet, where BNYVV infection reduces BSBMV
accumulation in both susceptible and resistant cultivars.
Considering all this observations we hypothesized that BNYVV and
BSBMV crossed study, exploiting their similarities and divergences, can improve
investigation of molecular interactions between sugar beets and Benyviruses.
The main achievement of our research is the production of a cDNA
biologically active clones collection of BNYVV and BSBMV RNAs, from which
synthetic copies of both Benyviruses can be transcribed.
Moreover, through recombination experiments we demonstrated, for the
first time, the BNYVV RNA 1 and 2 capability to trans-replicate and encapsidate
BSBMV RNA 3 and 4, either the BSBMV RNA 1 and 2 capability to replicate
BNYVV RNA2 in planta. We also demonstrated that BSBMV RNA3 support
long-distance movement of BNYVV RNA 1 and 2 in B. macrocarpa and that
85
foreign sequence as p29HA, GFP and RFP, are successfully expressed, in C.
quinoa, by BSBMV RNA3 based replicon (RepIII) also produced by our
research. These results confirm the close correlation among the two viruses.
Interestingly, the symptoms induced by BSBMV RNA-3 on C. quinoa
leaves are more similar to necrotic local lesions caused by BNYVV RNA-5 p26
than to strongly chlorotic local lesions or yellow spot induced by BNYVV RNA-
3 encoded p25. As previous reported BSBMV p29 share 23% of amino acid
sequence identity with BNYVV p25 but identity increase to 43% when compared
with sequence of BNYVV RNA-5 p26.
Based on our results the essential sequence (Core region) for the longdistance
movement of BSBMV and BNYVV in B. macrocarpa, is not only
carried by RNA3s species but other regions, perhaps located on the RNA 1 and
2, could play a fundamental role in this matter.
Finally a chimeric RNA, composed by the 5’ region of RNA4 and 3’ region
of RNA3 of BSBMV, has been produced after 21 serial mechanically inoculation
of wild type BSBMV on C. quinoa plants. Chimera seems unable to express any
protein, but it is replicated and transcript in planta. It could represent an
important tool to study the interactions between Benyvirus and plant host.
In conclusion different tools, comprising a method to study synthetic
viruses under natural conditions of inoculum through P. Betae, have been
produced and new knowledge are been acquired that will allow to perform future
investigation of the molecular interactions between sugar beets and Benyviruses.
|
Page generated in 0.0475 seconds