PCV2 infection in vaccinated conventional gilts inseminated with PCV2b-spiked semen

The present trial investigated the effect of PCV2 vaccination on viremia, virus shedding and viral load in maternal tissues and foetuses of conventional gilts inseminated with PCV2b-spiked semen. Twelve gilts were randomly divided into two groups of six animals each (vaccinated infected, VI; non-vaccinated infected, NVI). Estrus synchronization was followed by artificial insemination (AI) with a single PCV2 negative semen dose supplemented with 0.2 mL of a PCV2b suspension containing 104.4 TCID50/50 \u3bcL (total viral dose: 105 TCID50). Vaginal, nasal and faecal swabs, and blood samples were collected weekly from two days before artificial insemination till the end of the experimental period (55 days post AI; DPAI) and tested by real-time PCR (qPCR) for PCV2; sera were tested for anti- PCV2 antibodies. During necropsy foetal and maternal tissues were collected for qPCR and histopathology. In each of the VI and NVI groups three out of the six gilts were pregnant at 29 DPAI. The VI group showed a significantly lower proportion of PCR-positive swabs: 24.6% VI vs 71.3% NVI. PCV2 clearance was demonstrated by qPCR in lymphoid tissue during the trial in the VI group. Only one foetus was PCV2-positive (in the NVI group) and three amniotic fluids of the NVI group. PCV2 was found in a significantly lower proportion of the placenta of foetuses in the VI group (39%) than the NVI group (77%). The PCV2 vaccine seems to play an active role in reducing virus shedding, tissue viral load and foetoplacental infection

Upwind preconditioned conjugate gradients for finite element transport models

The iterative weighted residual solution of diffusive-convective equations may easily fall to converge in convection-dominated models. If the classical Galerkin approach is used, oscillations may also occur. To cope with this problem, an upwind weighting technique may prove appropriate. In the present paper an upwind finite element model is developed to analyze the 2-D transport of subsurface contaminants and is solved by preconditioned generalized conjugate residual schemes (GCR) especially designed for unsymmetric matrices. Three different algorithms, the ORTHOMIN(k), the GCR(k), and the Minimal Residual are compared on test problems whose size is up to 1500 for a wide range of Peclet and Courant numbers. The numerical results show that these numerical schemes are all robust, efficient, and reliable. The performace of the Minimal Residual is usually better, and particularly so for lage-sized problems

Optimization of a snow network by multivariate statistical analysis

The aim of the present work is that of analysing the data of snow-cover measurements carried out in the northeastern Alps by the Italian National Electricity Board (ENEL) since 1966, in order to select a reduced number of measurement stations from which to evaluate the water equivalent amount. The selection was based on cluster methods for identification of homogeneous areas and afterwards on principal componenet analyssis for individualization of representative stations. The results confirm that by employing a set of reduced input data the output is only moderatl\ely affected

Influenza dei fattori climatici e topografici sul regime di frequenza delle piene nel Triveneto

Il presente studio prende in esame il Triveneto, vasta area geografica comprendente le Alpi Orientali italiane, ed ha tre obiettivi principali: (1) valutare l’influenza dei fattori climatici e di scala sul regime di frequenza delle piene; (2) verificare la possibile presenza di alterazioni del regime di frequenza dei massimi annuali di portata al colmo di piena; (3) sviluppare una procedura aggiornata per la stima delle piene di progetto in Triveneto impiegando tecniche di raggruppamento di bacini basate su criteri di similitudine idrologica col bacino di interesse (approccio della regione di influenza, Region of Influence, RoI). Lo studio è pervenuto alle seguenti conclusioni: (1) l’influenza dei fattori climatici e topografici sul regime di frequenza delle piene in Triveneto risulta simile a quella recentemente osservata a scala europea in analoghi contesti morfologici e climatici; (2) nonostante non si siano riscontrate evidenze di alterazioni significative e generalizzate del regime di frequenza delle piene, le indagini hanno messo in risalto come un singolo anno caratterizzato da piene eccezionali possa influenzare notevolmente i modelli regionali di frequenza delle piene; (3) infine, è confermata per l’area in esame una marcata eterogeneità spaziale del regime di frequenza delle piene; in quest’ottica si raccomanda per essa un aggiornamento della procedura di riferimento per la stima della portata di progetto sulla base di procedure analoghe al RoI, che consentano di rappresentare l’influenza di fattori climatici e topografici sul regime di frequenza degli estremi idrometrici.Our study focuses on Triveneto, a broad geographical region which includes the Italian Eastern Alps. The objective of our study is threefold: (1) to inspect climatic and scale controls on flood frequency regime; (2) to verify the possible presence of changes in flood frequency regime by applying non-parametric statistical tests to annual maximum series of flood peak discharges and by evaluating the possible presence of changes in time of regional statistics of hydrometric extremes; (3) to develop an updated reference procedure for design flood estimation in Triveneto by using a focused-pooling approach (i.e. Region of Influence, RoI). Our study leads to the following conclusions: (1) climatic and scale controls on flood frequency regime in Triveneto are similar to the controls that were recently found at European scale in an analogous morpho-climatic context; (2) although we found no significant uniform changes in the flood frequency regime in the study area, our analyses highlight how a single year characterized by extreme floods can have a remarkable influence on regional flood frequency models; (3) finally, our analyses indicate for the study region a high heterogeneity degree in the flood frequency regime; therefore we recommend an update of the existing reference procedure for design flood estimation, referring to procedures similar to the RoI approach, which properly represents climate and scale controls on flood frequency regime

Hydro-power production and fish habitat suitability: Assessing impact and effectiveness of ecological flows at regional scale

Anthropogenic activities along streams and rivers may be of major concern for fluvial ecosystems, e.g. abstraction and impoundment of surface water resources may profoundly alter natural streamflow regimes. An established approach aimed at preserving the behavior and distribution of fluvial species relies on the definition of ecological flows (e-flows) downstream of dams and diversion structures. E-flow prescriptions are usually set by basin authorities at regional scale, often without a proper assessment of their impact and effectiveness. On the contrary, we argue that e-flows should be identified on the basis of (i) regional and (ii) quantitative assessments. We focus on central Italy and evaluate the effects on habitat suitability of two near-threatened fish species (i.e. Barbel and Chub) and an existing hydro-power network when shifting from the current time-invariant e-flow policy to a tighter and seasonally-varying soon-to-be-enforced one. Our example clearly shows that: (a) quantitative regional scale assessments are viable even when streamflow observations are entirely missing at study sites; (b) aprioristic e-flows policies may impose releases that exceed natural streamflows for significantly long time intervals (weeks, or months); (c) unduly tightening e-flow policies may heavily impact regional hydro-power productivity (15% and 42% losses on annual and seasonal basis, respectively), yet resulting in either marginal or negligible improvements of fluvial ecosystem

Reproduction in porcine circovirus type 2 (PCV2) seropositive gilts inseminated with PCV2b spiked semen.

BACKGROUND: Since 1999, field evidence of transplacental infection by porcine circovirus type 2 (PCV2) and reproductive failure has been reported in pigs. The objective of this study was to evaluate the clinical and pathological consequences of PCV2 infection in conventional PCV2-seropositive gilts by insemination with PCV2b-spiked semen. RESULTS: Six PCV2 seropositive gilts were inseminated with PCV2b-supplemented semen (infected) and three animals with semen and cell culture medium (controls). Only three out of the six infected animals were pregnant by ultrasonography on day 29 after insemination, while two out of the three controls were pregnant. One control gilt aborted on day 23 after insemination but not due to PVC2. Viraemia was demonstrated in four out of six infected and in one control gilt that became infected with PCV2a. Anti-PCV2 antibody titres showed dynamic variations in the infected group throughout the study. Among infected gilts, the animal with the lowest anti-PCV2 titre (1/100) at the beginning of the experiment and another that reached a similar low value during the experiment showed evident seroconversion over time and had also PCV2 positive foetuses. One placenta displayed mild focal necrosis of the chorionic epithelium positively stained by immunohistochemistry for PCV2 antigen. CONCLUSIONS: PCV2-seropositive gilts can be infected with PCV2 after intrauterine exposure and low maternal antibody titre may increase the probability of a foetal infection