Dating of newly formed minerals in geothermal fields through Th series short lived isotopes: Check on mineral of known age and implications to fluid-rock interactions

The ²²⁸Th/²²⁸Ra activity ratio can provide a tool for age measurements of newly formed minerals, down to about 15 yr. A general discussion of the method is followed by an experimental check on an aphthitalite brine, crystallized from a geothermal well at Cesano (Rome) in July, 1978 (the real age is 85 ± 5 months). It yielded an age of 75 + 8/-5 months through alpha-spectrometry activity measurements, and 85 ± 3 months through gamma-spectrometry activity measurements. A residence time of the fluid in the rock ranging from 3 to 10 centuries has been estimated by comparing the Ra isotopic composition of the fluid with the U/Th ratio of the wall rocks, according to a model proposed by Cherdyntsev (1971).     

A mobile microrobot actuated by a new electromagnetic wobblemicromotor

Microactuators are perhaps the most critical components of micromechatronic systems. Micromotors with diameters in the range between 10-1 mm are needed, but are not readily available for practical use. This paper describes a teleoperated mobile microrobot, actuated by a new electromagnetic wobble micromotor, and designed to participate in the “International Micro Robot Maze Contest" organized every year in Nagoya, Japan. This competition is an excellent benchmark to compare the performance of different microactuators. The working principle, design, fabrication, and performance of the wobble micromotor are described. The microrobot has a volume of 1 cm³ and incorporates two wobble micromotors, the rotors of which are the driving wheels. The micromotor generates a torque of 350 μN·m at each step and a maximum speed of about 180 r/min. The operator controls the motion of the microrobot by a remote joystick connected to the microrobot by flexible ultraminiature wires. The microrobot is highly maneuverable, has a maximum speed of 10 cm/s and can climb a slope of 15°. Two microrobots, which differ only in some constructive details, were fabricated. A smaller version (4-mm diameter) of the wobble micromotor has been developed for use in an innovative miniature robot system for diagnosis and intervention in the colon     

Development and Experimental Analysis of a Soft Compliant Tactile Microsensor for Anthropomorphic Artificial Hand

This paper presents the development and preliminary experimental analysis of a soft compliant tactile microsensor (SCTM) with minimum thickness of 2 mm. A high shear sensitive triaxial force microsensor was embedded in a soft, compliant, flexible packaging. The performance of the whole system, including the SCTM, an electronic hardware and a processing algorithm, was evaluated by static calibration, maximum load tests, noise and dynamic tests, and by focusing on slippage experiments. A proper tradeoff between final robustness and sensitivity of the tactile device was identified. The experiments showed that the tactile sensor is sufficiently robust for application in artificial hands while sensitive enough for slip event detection. The sensor signals were elaborated with the cumulative summation algorithm and the results showed that the SCTM system could detect a slip event with a delay from a minimum of 24.5 ms to a maximum of 44 ms in the majority of experiments fulfilling the neurophysiological requirement.     

Ultrasensitive detection of unstained proteins in acrylamide gels by native UV fluorescence

Visualization of proteins inside acrylamide and other gels usually relies on different staining methods. To omit the protein-staining procedure, we visualized unstained proteins inside acrylamide gels by laser excitation with ultraviolet (UV) light (280 nm, 35 mJ/cm2) and directly detected native UV fluorescence. In one-dimensional gels, a detection limit as low as 1 ng for bovine serum albumin and 5 ng for other proteins with a linear dynamic range (2.7 orders of magnitude) comparable to state of the art fluorescent dyes could be achieved. In addition, the application of this method to 20 microg of a whole cell lysate separated in a two-dimensional gel showed more than 600 spots. Since protein labeling always represents a serious obstacle in protein identification technologies, the working efficiency with our procedure can be considered as a significant improvement for protein visualization and reproducibility in proteomics.     

Representation of journals from five neighboring European countries in the Journal Citation Reports

This study explores the representation of scientific journals from Italy, Hungary, Slovenia, Croatia, and Serbia and Montenegro in the Thomson Scientific’s 2005 Journal Citation Reports (JCR). The number of journals covered by JCR was analyzed in relation to scientific productivity of selected countries and the size of their economies, and no apparent relationship between these factors was found. Our findings suggest that other factors, including the quality of individual journals, may influence how many journals a country will have in the JCR.     

Universality in ant behaviour

Prediction for social systems is a major challenge. Universality at the social level has inspired a unified theory for urban living but individual variation makes predicting relationships within societies difficult. Here, we show that in ant societies individual average speed is higher when event duration is longer. Expressed as a single scaling function, this relationship is universal because for any event duration an ant, on average, moves at the corresponding average speed except for a short acceleration and deceleration at the beginning and end. This establishes cause and effect within a social system and may inform engineering and control of artificial ones.