Daily and circadian variations in 2-[125I]-iodomelatonin binding sites in the pike brain (Esox lucius)

The fish pineal organ, through its 24 h rhythmic release of melatonin, acts as a transducer of the photoperiod, influencing different physiological functions (e.g. reproduction, growth). We have investigated the binding of 2-[125I]iodomelatonin to whole brain membrane preparations from pikes (Esox lucius L., teleost) maintained for 24-48 h under different photoperiodic conditions. Specific binding was stable, reversible, saturable and sensitive to the presence of a GTP analogue. Scatchard analysis revealed one class of binding sites. Displacement experiments suggested the presence of two components with affinities in the femtomolar and nanomolar range of concentrations, respectively. The Bmax exhibited monophasic nycthemeral variations, with higher values at the light-to-dark transition (34.0 +/- 4.5 fmol/mg protein) and low values during the second half of night (10.0 +/- 1.0 fmol/mg protein). Under the same conditions, the KD exhibited biphasic variations: values were low during daytime and at the middle of the dark phase (approximately 100 pM); they were high at the beginning (approximately 225 pM) and at the end (approximately 330 pM) of the night. These variations were maintained under constant light (LL) and constant darkness (DD). Thus, the variations in the number and affinity of the melatonin binding sites were controlled by circadian oscillators, synchronized by the photoperiod. The nature of these oscillators is not known. Therefore, in fish, we suggest that the photodependent effects of melatonin result from the circadian variations of both its production by the pineal and its binding sites in the brain.     

Thermal reactions between aluminum and palladium layered films

Phase formation and reaction during annealing in thin film couples of aluminum and palladium were studied by transmission electron microscopy, X-ray diffraction and Auger depth profiling techniques in the temperature range 200– 500°C. The known bulk phases of Al₃Pd₂, AlPd, Al₃Pd₅ and AlPd₂ were confirmed and two additional aluminum-rich phases were tentatively identified as Al₃Pd and Al₄Pd. In all the samples studied the reactions were initiated by the formation of the β-AlPd phase, which was then followed by the formation of the Al₃Pd₂ phase. Subsequent reactions caused precipitation of AlPd₂ particles if unreacted palladium was present, otherwise Al₄Pd particles were precipitated. The reaction rate was usually reduced if single-crystal, instead of polycrystalline, palladium film was used.     

Optimisation of conditions for the degradation of mimosine in Leucaena leucocephala leaf

A study was made of the rate of degradation of mimosine to 3-hydroxy-4(1H)-pyridone in harvested leucaena leaf under various conditions. Optimum rates of degradation of an aqueous leucaena slurry were at pH 8.0 and 45°C with virtual total loss of mimosine in 10 min. Heating the intact leaf also reduced the mimosine content with the maximum rate of degradation at 70°C. The results have implications for reducing the toxicity of leucaena used for stock feed.     

Building information

Ron Brewer, Head of Publishing at the UK's Building Research Establishment, BRE, describes the research that indicates that the basic requirements of technical literature are not being met. This paper accepts that users of information are influenced by the way documents are presented and looks at 13 different attributes of technical publications recording how various professional groups placed them into their order of preference.     

Auditory frequency discrimination in infancy.

Investigated the ability of 14 5–8 mo olds and 5 college students to detect changes in the frequency of pure tones. A head turn for visual reinforcement technique was used to obtain difference thresholds for infants and adults at 1,000, 2,000, and 3,000 Hz. With signals presented at 70 db above adult detection thresholds, infants reliably detected frequency changes on the order of 2%, whereas adults detected changes of about 1%. Data confirm previous findings indicating that infants can distinguish different frequencies and can make relatively fine discriminations. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Drug and alcohol use among drivers admitted to a Level-1 trauma center

The purpose of this research was to determine the incidence and prevalence of drug use, alcohol use, and the combination of drug and alcohol use among motor vehicle crash (MVC) victims admitted to a Level-1 trauma center. In a 90-day study, nearly two-thirds of trauma center admissions were victims of motor vehicle crashes. Blood and urine was collected from 168 MVC victims of whom 108 were identified as the driver in the crash. Toxicology results indicated that 65.7% of drivers tested positive for either commonly abused drugs or alcohol. More than half of the drivers tested positive for drugs (50.9%) other than alcohol, with one in four drivers testing positive for marijuana use. About one-third of those using drugs had also been drinking, but alcohol was detected in only 30.6% of all injured drivers. Within the total MVC patient pool, passenger drug/alcohol use was equivalent to the driver population; however, injured pedestrians had higher rates of alcohol only than other MVC victims. There were no significant differences in drug and alcohol use between MVCs and trauma admissions of other causes. Of the patients with positive toxicology results, less than half (42%) were referred for evaluation for substance abuse disorders.     

Enhancements to GPS operations and clock evaluations using a "total" Hadamard deviation

We describe a method based on the total deviation approach whereby we improve the confidence of the estimation of the Hadamard deviation that is used primarily in global positioning system (GPS) operations. The Hadamard-total deviation described in this paper provides a significant improvement in confidence indicated by an increase of 1.3 to 3.4 times the one degree of freedom of the plain Hadamard deviation at the longest averaging time. The new Hadamard-total deviation is slightly negatively biased with respect to the usual Hadamard deviation, and tau values are restricted to less than or equal to T/3, to be consistent with the usual Hadamard's definition. We give a method of automatically removing bias by a power-law detection scheme. We review the relationship between Kalman filter parameters and the Hadamard and Allan variances, illustrate the operational problems associated with estimating these parameters, and discuss how the Hadamard-total variance can improve management of present and future GPS satellite clocks.