Calculation of the axion mass based on high-temperature lattice quantum chromodynamics.

Unlike the electroweak sector of the standard model of particle physics, quantum chromodynamics (QCD) is surprisingly symmetric under time reversal. As there is no obvious reason for QCD being so symmetric, this phenomenon poses a theoretical problem, often referred to as the strong CP problem. The most attractive solution for this requires the existence of a new particle, the axion-a promising dark-matter candidate. Here we determine the axion mass using lattice QCD, assuming that these particles are the dominant component of dark matter. The key quantities of the calculation are the equation of state of the Universe and the temperature dependence of the topological susceptibility of QCD, a quantity that is notoriously difficult to calculate, especially in the most relevant high-temperature region (up to several gigaelectronvolts). But by splitting the vacuum into different sectors and re-defining the fermionic determinants, its controlled calculation becomes feasible. Thus, our twofold prediction helps most cosmological calculations to describe the evolution of the early Universe by using the equation of state, and may be decisive for guiding experiments looking for dark-matter axions. In the next couple of years, it should be possible to confirm or rule out post-inflation axions experimentally, depending on whether the axion mass is found to be as predicted here. Alternatively, in a pre-inflation scenario, our calculation determines the universal axionic angle that corresponds to the initial condition of our Universe.

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.

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.

Detection and imaging of atmospheric radio flashes from cosmic ray air showers.

The nature of ultrahigh-energy cosmic rays (UHECRs) at energies >10(20) eV remains a mystery. They are likely to be of extragalactic origin, but should be absorbed within approximately 50 Mpc through interactions with the cosmic microwave background. As there are no sufficiently powerful accelerators within this distance from the Galaxy, explanations for UHECRs range from unusual astrophysical sources to exotic string physics. Also unclear is whether UHECRs consist of protons, heavy nuclei, neutrinos or gamma-rays. To resolve these questions, larger detectors with higher duty cycles and which combine multiple detection techniques are needed. Radio emission from UHECRs, on the other hand, is unaffected by attenuation, has a high duty cycle, gives calorimetric measurements and provides high directional accuracy. Here we report the detection of radio flashes from cosmic-ray air showers using low-cost digital radio receivers. We show that the radiation can be understood in terms of the geosynchrotron effect. Our results show that it should be possible to determine the nature and composition of UHECRs with combined radio and particle detectors, and to detect the ultrahigh-energy neutrinos expected from flavour mixing.

[The mobile child and adolescent psychiatric service: an effective treatment model in rural areas]. / Der mobile kinder- und jugendpsychiatische Dienst: Ein wirksames Versorgungsmodell für ländliche Regionen.

A mobile unit for child and adolescent psychiatry is described that serves two counties with a combined population of 400 000. In both counties the unit is the third most frequently used outpatient service, providing 21% of all outpatient care in child and adolescent psychiatry in Marburg-Biedenkopf and 40% in Waldeck-Frankenberg. After the outpatient clinics this unit serves the largest number of patients from the lower social classes, in the case of psychotherapy the majority (54.1%). This unit also makes the largest number of home visits. On the whole, the mobile unit can be considered an effective means of providing mental health services in rural areas.

[Minimal brain dysfunction--on the revision of a clinical concept. Clinical data of a total pediatric and adolescent psychiatric patient population]. / Minimale zerebrale Dysfunktion--zur Revision eines klinischen Konzeptes. Erhebungen an einer vollständigen kinder- und jugendpsychiatrischen Inanspruchnahmepopulation.

After a discussion of the changes of the MCD concept over the years, the authors describe their own investigation of a total sample of 3280 children, attending outpatient and inpatient facilities of three counties with a total population of 574,000 inhabitants. The aim of the study was to investigate the frequency, sex distribution, and social class dependency of the MCD-diagnosis and its relationship to clinical-psychiatric syndromes. The following results were obtained: There is a strong correlation of MCD-diagnosis with age, sex, and social class. MCD was most frequently diagnosed in the age groups of 3-6, 6-9 and 9-12 years, being twice as frequent in boys than in girls and dominating among the lower social classes. The frequency of MCD in the total sample was 11%, taking into consideration all age-classes. MCD was significantly associated only with two psychiatric syndromes: conduct disorders and hyperkinetic syndrome. There was no correlation with emotional disorders or neurosis, however, a very strong one with specific delays in development, defined according to the multiaxial classification system. 72% of the children diagnosed as MCD-children revealed specific delays in development. But this high correlation was caused only by two conditions: developmental speech/language disorders and specific motor retardation. There was no correlation between MCD and specific reading retardation nor with other specific learning difficulties or mixed developmental disorders. Future research in this field should look upon the so-called MCD more in terms of general developmental delays than in terms of brain pathology.