Temporal dynamics and spatial patterns of Galliform birds in Trentino – Italy.

This study examines the population dynamics of 5 species of closely related galliform birds in the Dolomites, north-east Italian Alps. The aim was to assess the dynamics of these populations at the edge of their European distribution and to investigate the patterns of spatial synchrony. Three main types of data sets were used in the analysis. First, the hunting statistics collected from 210 hunting areas between 1965 and 1994 for each of the 5 galliform species. Second, rock partridge count data from 29 sample areas during the period 1994 to 1998. Third, guts helminths collected from rock partridge shot between 1995 and 1998. Tetraonid populations at the edge of their southern European distribution exhibited a weak tendency to cycle. These cycles only showed significant negative autocorrelation at half the cycle period and were classified as phase-forgetting quasi-cycles contrasting with the more regular oscillations recorded in the same species in Finland. Cycles were not found in time series of black grouse Tetrao tetrix or capercaillie Tetrao urogallus. Rock partridge Alectoris graeca saxatilis exhibited a higher tendency to fluctuate. Rock partridge populations declined between 1965 and 1975 with populations in the western province declining earlier. Total winter loss and spring to summer loss of adults were the most important population parameters influencing the year to year change in numbers. There was some compensation to hunting mortality. The hypothesis that macroparasites may be of significance in destabilising partridge abundance and generating cyclic oscillations was examined by investigating the intensity of parasite infection in cyclic and non cyclic populations. Ascaridia compar and Heterakis tenuicauda were prevalent in the rock partridge populations and significantly greater in cyclic populations than non-cyclic populations. There were large variations in synchrony both within and between species and only weak negative relationships between synchrony and distance. Species in neighbouring habitats were more likely to be in synchrony than species separated by several habitats. A detailed spatial analysis on rock partridge populations found an increase in synchrony with scale from the population to meta-population level. Rock partridge clustered in two groups DRY and WET and synchrony was stronger in populations in the same habitat with populations in the dry habitat showing a higher tendency to cycle. The modelling of the long term dynamics of spatially structured populations indicated that environmental stochasticity was the main cause of synchrony although there is also some dispersal between populations and the importance of this varied between species. Population viability analysis of the grey partridge Perdix perdix in populations in Britain between 1930-1960 and the "declining" continental populations from 1970 to 1994 confirms that the UK populations prior to 1960 were more resilient than the continental populations. Even very small harvesting cannot be tolerated by the present continental populations and this may indicate that the persistence of hunting activity, although with a limited effort, has contributed to the extinction of many sub-populations and is critically threatening the remaining ones

Which solar neutrino data favour the LMA solution?

Assuming neutrino oscillations, global analyses of solar data find that the LOW solution is significantly disfavoured, leaving LMA as the best solution. But the preference for LMA rests on three weak hints: the spectrum of earth matter effects (Super-Kamiokande sees an overall day/night asymmetry only at 1 sigma), the Cl rate (but LMA and LOW predictions are both above the measured value), the Ga rate (newer data decrease towards the LOW predictions both in GNO and SAGE). Only new data will tell us if LMA is the true solution.Comment: 4 pages, 2 figure

Effects of blood transfusion on exercise capacity in thalassemia major patients

Anemia has an important role in exercise performance. However, the direct link between rapid changes of hemoglobin and exercise performance is still unknown.To find out more on this topic, we studied 18 beta-thalassemia major patients free of relevant cardiac dysfunction (age 33.5±7.2 years,males = 10). Patients performed a maximal cardiopulmolmonary exercise test (cycloergometer, personalized ramp protocol, breath-by-breath measurements of expired gases) before and the day after blood transfusion (500 cc of red cell concentrates). After blood transfusion, hemoglobin increased from 10.5±0.8 g/dL to 12.1±1.2 (p<0.001), peak VO2 from 1408 to 1546mL/min (p<0.05), and VO2 at anaerobic threshold from 965 to 1024mL/min (p<0.05). No major changes were observed as regards heart and respiratory rates either at peak exercise or at anaerobic threshold. Similarly, no relevant changes were observed in ventilation efficiency, as evaluated by the ventilation vs. carbon dioxide production relationship, or in O2 delivery to the periphery as analyzed by the VO2 vs. workload relationship. The relationship between hemoglobin and VO2 changes showed, for each g/dL of hemoglobin increase, a VO2 increase = 82.5 mL/min and 35 mL/min, at peak exercise and at anaerobic threshold, respectively. In beta-thalassemia major patients, an acute albeit partial anemia correction by blood transfusion determinates a relevant increase of exercise performance, observed both at peak exercise and at anaerobic threshold

Post-traumatic pseudoaneurysm of internal mammary artery: a case report

Pseudoaneurysm of the internal mammary artery can be a rare complication of surgery, particularly post-sternotomy, or determined by a direct trauma, usually a stab wound. This report presents a pseudoaneurysm by a stab, diagnosed by chest computed tomography scan performed for hemothorax recurrence. The patient underwent left thoracotomy in third intercostal space; mammary vessels were identified above and below the pseudoaneurysm sac and tied. The postoperative course was uneventful

Abelian family symmetries and the simplest models that give theta13=0 in the neutrino mixing matrix

I construct predictive models of neutrino mass and mixing that have fewer parameters, both in the lepton sector and overall, than the default seesaw model. The predictions are theta13=0 and one massless neutrino, with the models having a Z4 or Z2 symmetry and just one extra degree of freedom: one real singlet Higgs field. It has been shown that models with an unbroken family symmetry, and with no Higgs fields other than the Standard Model Higgs doublet produce masses and mixing matrices that have been ruled out by experiment. Therefore, this article investigates the predictions of models with Abelian family symmetries that involve Higgs singlets, doublets and triplets, in the hope that they may produce the maximal and minimal mixing angles seen in the best fit neutrino mixing matrix. I demonstrate that these models can only produce mixing angles that are zero, maximal or unconfined by the symmetry. The maximal mixing angles do not correspond to physical mixing, so an Abelian symmetry can, at best, ensure that theta13=0, while leaving the solar and atmospheric mixing angles as free parameters. To generate more features of the best-fit mixing matrix a model with a non-Abelian symmetry and a complicated Higgs sector would have to be used.Comment: 16 pages, no figure

Standard and Non-Standard Physics in Neutrino Oscillations

We analyze the impact of recent solar and atmospheric data in the determination of the neutrino oscillation parameters, taking into account that both the solar nu_e and the atmospheric nu_mu may convert to a mixture of active and sterile neutrinos. Furthermore, in the context of the atmospheric neutrino problem we discuss an extended mechanism of neutrino propagation which combines both oscillations and non-standard neutrino-matter interactions. We use the most recent neutrino data, including the 1496-day Super-K solar and atmospheric data samples, the latest SNO spectral and day/night solar data, and the final MACRO atmospheric results. We confirm the clear preference of all the data for pure-active oscillation solutions, bounding the fraction of sterile neutrino involved in oscillations to be less than 52% in the solar sector and less than 40% in the atmospheric sector, at 3 sigma. For the atmospheric case we also derive a bound on the total amount of non-standard neutrino-matter interactions, bounding the flavor-changing component to -0.03 <= epsilon <= 0.02 and the non-universal component to |epsilon'| <= 0.05.Comment: 6 pages, LaTeX file using espcrc2.sty, 1 table and 3 figures included. Talk given at the XXX International Meeting on Fundamental Physics (Jaca, Spain, 28/01-1/02/2002

Evolutionary History and Attenuation of Myxoma Virus on Two Continents

The attenuation of myxoma virus (MYXV) following its introduction as a biological control into the European rabbit populations of Australia and Europe is the canonical study of the evolution of virulence. However, the evolutionary genetics of this profound change in host-pathogen relationship is unknown. We describe the genome-scale evolution of MYXV covering a range of virulence grades sampled over 49 years from the parallel Australian and European epidemics, including the high-virulence progenitor strains released in the early 1950s. MYXV evolved rapidly over the sampling period, exhibiting one of the highest nucleotide substitution rates ever reported for a double-stranded DNA virus, and indicative of a relatively high mutation rate and/or a continually changing selective environment. Our comparative sequence data reveal that changes in virulence involved multiple genes, likely losses of gene function due to insertion-deletion events, and no mutations common to specific virulence grades. Hence, despite the similarity in selection pressures there are multiple genetic routes to attain either highly virulent or attenuated phenotypes in MYXV, resulting in convergence for phenotype but not genotype. © 2012 Kerr et al

Immune regulation of a chronic bacteria infection and consequences for pathogen transmission

<p>Abstract</p> <p>Background</p> <p>The role of host immunity has been recognized as not only playing a fundamental role in the interaction between the host and pathogen but also in influencing host infectiousness and the ability to shed pathogens. Despite the interest in this area of study, and the development of theoretical work on the immuno-epidemiology of infections, little is known about the immunological processes that influence pathogen shedding patterns.</p> <p>Results</p> <p>We used the respiratory bacterium <it>Bordetella bronchiseptica </it>and its common natural host, the rabbit, to examine the intensity and duration of oro-nasal bacteria shedding in relation to changes in the level of serum antibodies, blood cells, cytokine expression and number of bacteria colonies in the respiratory tract. Findings show that infected rabbits shed <it>B. bronchiseptica </it>by contact up to 4.5 months post infection. Shedding was positively affected by number of bacteria in the nasal cavity (CFU/g) but negatively influenced by serum IgG, which also contributed to the initial reduction of bacteria in the nasal cavity. Three main patterns of shedding were identified: i- bacteria were shed intermittently (46% of individuals), ii- bacteria shedding fell with the progression of the infection (31%) and iii- individuals never shed bacteria despite being infected (23%). Differences in the initial number of bacteria shed between the first two groups were associated with differences in the level of serum antibodies and white blood cells. These results suggest that the immunological conditions at the early stage of the infection may play a role in modulating the long term dynamics of <it>B. bronchiseptica </it>shedding.</p> <p>Conclusions</p> <p>We propose that IgG influences the threshold of bacteria in the oro-nasal cavity which then affects the intensity and duration of individual shedding. In addition, we suggest that a threshold level of infection is required for shedding, below this value individuals never shed bacteria despite being infected. The mechanisms regulating these interactions are still obscure and more studies are needed to understand the persistence of bacteria in the upper respiratory tract and the processes controlling the intensity and duration of shedding.</p