First Experimental Characterization of Microwave Emission from Cosmic Ray Air Showers.

We report the first direct measurement of the overall characteristics of microwave radio emission from extensive air showers. Using a trigger provided by the KASCADE-Grande air shower array, the signals of the microwave antennas of the Cosmic-Ray Observation via Microwave Emission experiment have been read out and searched for signatures of radio emission by high-energy air showers in the GHz frequency range. Microwave signals have been detected for more than 30 showers with energies above 3×10^{16} eV. The observations presented in this Letter are consistent with a mainly forward-directed and polarized emission process in the GHz frequency range. The measurements show that microwave radiation offers a new means of studying air showers at E≥10^{17} eV.

Coronary artery disease, cerebral non-fatal ischemic stroke in retinal vein occlusion: an 8-yr follow-up.

Forty-five consecutive subjects (26M, 19F; mean age 54 ± 14 yrs) with a diagnosed retinal vein occlusion (RVO), were followed-up for 8 yrs. As many as 145 sex-age- and blood pressure-matched individuals (78M, 67F; mean age 54.4 ± 13.5 yrs), that did not experience any vascular event, served as controls. At the time of the RVO, controls and subjects did not differ as to hypercholesterolemia, hypertrigliceridemia, diabetes mellitus, smoking habits, inherited/acquired thrombophilia. At the follow-up completion, they differed as to statin consumption (p = 0.016). During the 8-yrs follow-up, in the control population, 11 out of 145 (7.6%) subjects had experienced a major vascular event (8 coronary artery disease; 3 cerebral non-fatal ischemic stroke). In contrast, of the 45 subjects with a history of RVO, as many as 10 (22.2%) had experienced a major vascular event: 4 coronary artery disease; 4 cerebral non-fatal ischemic stroke; 2 cardiovascular + cerebrovascular event (p = 0.012). A prolonged antiplatelet treatment, prior to the major vascular event, was found in 5/45 cases (11.1%) vs 23/145 (15.9%) controls (p = 0.63). In contrast, a long-lasting administration of anti-hypertensive drugs, to achieve a control of blood pressure, was found in 83.4% of controls and only in 46.7% of cases (p < 0.0001). In conclusion, in a 8-yr follow-up, coronary artery disease and/or non-fatal ischemic stroke were more common in subjects with a history of RVO than in a large setting of subjects comparable for cardiovascular risk factors. These data also argue for RVO as a vascular disease in which aggressive anti-hypertensive therapy to prevent stroke and/or myocardial infarction is needed.

Kneelike structure in the spectrum of the heavy component of cosmic rays observed with KASCADE-Grande.

We report the observation of a steepening in the cosmic ray energy spectrum of heavy primary particles at about 8×10(16) eV. This structure is also seen in the all-particle energy spectrum, but is less significant. Whereas the "knee" of the cosmic ray spectrum at 3-5×10(15) eV was assigned to light primary masses by the KASCADE experiment, the new structure found by the KASCADE-Grande experiment is caused by heavy primaries. The result is obtained by independent measurements of the charged particle and muon components of the secondary particles of extensive air showers in the primary energy range of 10(16) to 10(18) eV. The data are analyzed on a single-event basis taking into account also the correlation of the two observables.

Dissolved and particulate humic substances in water channels in the historic centre of Venice.

The presence of humic substances, both in solution and as particulate, was studied in channels of the historic centre of Venice. The amount of particulate, its composition (organic and inorganic fraction) and the ratio between organic matter and humic substances were also considered. The sampling campaign was planned in 2001-02 from November to May. Three samplings in 20 stations representative of a large typical urban area were performed. The results obtained show that the composition of the particulate is variable, whereas the concentration of both dissolved and particulate humic substances is relatively homogeneous. Fulvic acids present in particulate are less homogeneous than dissolved forms; furthermore, the humification rate of organic matter is variable. Humic acids are absent, both in particulate and in dissolved forms.

Diabetes, vascular complications and antiplatelet therapy: open problems.

Diabetes mellitus is commonly associated with both microvascular and macrovascular complications (coronary artery disease, cerebrovascular events, severe peripheral vascular disease, nephropathy and retinopathy). There is wide evidence demonstrating that platelet degranulation and synthesis of TxA2 are increased in diabetic patients. For this reason, many studies on anti-platelet therapy have been made to reduce thrombotic complication of diabetes mellitus. Some diabetic patients, although treated with ASA, have a high prevalence of recurrent thrombotic events, which may presumably be due to an "ASA resistance". Nevertheless, this drug remains the one with the greatest benefit. To optimize its function, we should try to understand the causes of "aspirin resistance", try to find the most suitable dosage, recommending patients to comply constantly with the prescription given and to avoid interactions with other drugs. "Clopidogrel resistance" is a term not clearly defined. The clinical implications of "clopidogrel resistance" are unknown. An important consideration affecting the use of aspirin in diabetic patients is its interaction with ACE-inhibitors. Another question is antiplatelet therapy in nephropathic diabetic patients. Although these patients are at high thrombotic and haemorrhagic risk, they should nevertheless be considered eligible to undergo antithrombotic therapy, taking into account the individual's haemorrhagic risk.