The Impact of Global Warming and Anoxia on Marine Benthic Community Dynamics: an Example from the Toarcian (Early Jurassic)

The Pliensbachian-Toarcian (Early Jurassic) fossil record is an archive of natural data of benthic community response to global warming and marine long-term hypoxia and anoxia. In the early Toarcian mean temperatures increased by the same order of magnitude as that predicted for the near future; laminated, organic-rich, black shales were deposited in many shallow water epicontinental basins; and a biotic crisis occurred in the marine realm, with the extinction of approximately 5% of families and 26% of genera. High-resolution quantitative abundance data of benthic invertebrates were collected from the Cleveland Basin (North Yorkshire, UK), and analysed with multivariate statistical methods to detect how the fauna responded to environmental changes during the early Toarcian. Twelve biofacies were identified. Their changes through time closely resemble the pattern of faunal degradation and recovery observed in modern habitats affected by anoxia. All four successional stages of community structure recorded in modern studies are recognised in the fossil data (i.e. Stage III: climax; II: transitional; I: pioneer; 0: highly disturbed). Two main faunal turnover events occurred: (i) at the onset of anoxia, with the extinction of most benthic species and the survival of a few adapted to thrive in low-oxygen conditions (Stages I to 0) and (ii) in the recovery, when newly evolved species colonized the re-oxygenated soft sediments and the path of recovery did not retrace of pattern of ecological degradation (Stages I to II). The ordination of samples coupled with sedimentological and palaeotemperature proxy data indicate that the onset of anoxia and the extinction horizon coincide with both a rise in temperature and sea level. Our study of how faunal associations co-vary with long and short term sea level and temperature changes has implications for predicting the long-term effects of “dead zones” in modern oceans

Circadian rhythm of tryptophan in normal volunteers

The daily changes of plasma free and total tryptophan were studied in 15 healthy volunteers. Six blood samples were taken for each subject. A method involving pH control was used. The results show that plasma free tryptophan concentrations progressively rise to reach a peak at 3.30 hr. The total tryptophan concentration reaches a peak at midnight

Timed-release dihydroergotamine in the prophylaxis of mixed headache. A study versus amitriptyline.

[No abstract available

Headache patients: different responses induced by naloxone during work-test.

The responses to work-test in ischemia (tourniquet technique), before and after I.V. injection of naloxone (2 mg) or saline, were investigated in healthy volunteers and patients suffering from various types of headache. The patients were examined during both painful and painless periods. We found that only the subjects suffering from migraine showed a significantly shortened pain tolerance at work-test in ischemia, after injection of naloxone, and only during painful periods. Psychogenic headache patients and migraine patients in painless periods showed responses during work-test similar to those in healthy volunteers, even after injection of naloxone. We believe that hyperalgesic effect of naloxone is due to involvement of beta-endorphin systems only during organic pain

POPULATION STRUCTURE ANALYSES OF TUBER BORCHII: THE ITALIAN BIANCHETTO TRUFFLE

Objectives: Tuber borchii (Ascomycota, order Pezizales) is an excellent truffle with a significant local market in Italy. Despite the great use of this truffle in scientific experiments, knowledge on its intraspecific variability is scarce. The objective of this work was to investigate the evolutionary forces shaping genetic variability in this ascomycetes with a classical phylogenetic approach and a stochastic models (Kingman, 2000) to study the gene flow, migration and mutation rate. Material and Methods : To handle these goals, analyses were carried out using 61 samples from 11 different Provinces of Italy trying to have, as far as possible, an heterogeneity in growing conditions, habitats and hosts. Samples were identified considering anatomo-morphological characters (Zambonelli et al,. 2000). On the other side, DNA was extracted and four loci markers (ITS, IGS, β-tubulin and PKC) were screened to look for polymorphisms. Phylogenetic analyses of the sequence data were performed with maximum parsimony and maximum likelihood with PAUP (Swofford, 2003) and data were combined with MrBAYES software (Huelsenbeck and Ronquist, 2001) to have more realistic information. Approximation of the evolutionary history of populations was facilitated by use of the SNAP Workbench (Price and Carbone, 2005). Results : Genetic data showed the presence of two different haplotypes named 1 and 2, which were difficultly resolved by morphological analyses. The haplotypes are descended from a common ancestral population at some time in the past and have since diverged with a very low level of gene flow with a weak asymmetrical migration from haplotype 1 to haplotype 2. Moreover the oldest mutations are found in the haplotype 2. Conclusion : These results may allow us to formulate an early hypothesis on the natural processes of evolution of Italian T. borchii populations, in fact the two major phylogenetic groups observed may represent a species partition where haplotype 1 and 2, could be in the beginning of a speciation event or represent cryptic species

The effect of bromocriptine on plasma catecholamine concentrations in normal volunteers

The effect of the ergot derivative bromocriptine (5 mg orally) on blood pressure and plasma catecholamine concentrations was explored in normal volunteers. A significant decrease of plasma noradrenaline was found, while dopamine and adrenaline concentrations did not change significantly. Systolic and diastolic blood pressures were significantly lowered at 150 min after administration. The hypotensive effect of bromocriptine seems to be mediated by a lowered release of noradrenaline from sympathetic nerve endings. It may be hypothesized that the drug stimulates presynaptic dopamine receptors located on postganglionic sympathetic nerves, thus inhibiting noradrenaline discharge

Numerical and experimental analysis of the energy performance of an air-source heat pump (ASHP) coupled with a horizontal earth-to-air heat exchanger (EAHX) in different climates

Geothermal energy has a huge potential in building applications. This paper proposes the use of an Air-Source Heat Pump (ASHP) system coupled with a Horizontal Earth-To-Air Heat Exchanger (EAHX) to reduce energy consumption in buildings. The novelty is to geothermally pre-heat or pre-cool the air source of the ASHP through the EAHX, reducing the electric power needed, keeping constant heating/cooling capacity. The behaviour of ASHP-EAHX system has been investigated by a numerical model implemented in TRNSYS. A total of 54 combinations have been obtained and tested varying ground thermal properties, burial depth, air flow rate and pipe length. The model has been validated with a real case showing a good agreement between simulated and monitored data. The study is focused on the city of Turin (North of Italy), compared with Brindisi (South of Italy), and extremely cold and hot climates like Tromsø (Norway) and Béchar (Algeria), respectively. The ASHP-EAXH performance has been investigated, by the comparison with the traditional ASHP, using different coefficients, such as the Coefficient of Performance (COP), the Energy Efficiency Ratio (EER), the Seasonal Coefficient of Performance (SCOP), and the Seasonal Energy Efficiency Ratio (SEER). The paper reveals how the ASHP-EAHX system show higher performance compared to the traditional ASHP, in all seasons. The overall merit is, for cold extremely climate, the reduction of the shutdown periods, when the outside temperature is below the limit operating temperature, and to allow the extension of the use of the heat pump to locations, where it is currently not convenient for the average outside temperature lower than the limit operating temperature of the heat pump