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Most current PET detector designs suffer from event mispositioning at high count rates, as scintillation light from nearby and nearly simultaneous gamma ray conversions becomes mixed. We have used the NEMA NU 2-2001 70 cm test phantom and a Na-22 point source to quantify this effect as a function of activity on two block-detector tomographs (the Siemens/CTI HR+ and the General Electric Discovery LS), and two Anger-type PET tomographs (the Siemens ECAM DUET and the Philips CPET+). After accounting for event losses due to dead time, we find that the number of counts on LORs passing through a cylinder of diameter and height equal to the point-source full width at tenth-maximum measured at low rate surrounding the point source decreases by between 9% (HR+) and 35% (CPET+) at the activity giving rise to peak noise equivalent count (NEC) rate. Mispositioned events act to reduce signal-to-noise ratio, both by reducing apparent activity at the originating location and by increasing the signal background. We have reformulated the conventional expression for NEC rate to account for this phenomenon. The new formulation of NEC, which we call NEC*, results in a lower peak value which in turn occurs at a lower activity concentration than for the conventional formulation. [ABSTRACT FROM AUTHOR]

Efficient and eco-friendly technologies are required to reduce the environmental effects of the beneficiation plants. Recently, there has been an interest in environmentally friendly alternative depressants. This study explored the effects of various depressants (AERO633, AERO7260, DP3124, DP3125, carboxymethyl cellulose (CMC), Cyquest4000, and sodium silicate) on chalcopyrite flotation. The experimental results indicated that AERO7260 has the best effect on chalcopyrite flotation, and the dosage is 50 g/t, it can improve the chalcopyrite recovery up to 93.35% as well as chalcopyrite grade up to 36.97%. Meanwhile, AERO7260 had an obvious depression effect on pyrite, reducing pyrite grade to 61.10% and pyrite recovery to 3.35%. Given its low reagent dosage and high selectivity, AERO7260 is a promising depressant that can be used for chalcopyrite flotation. The use of organic depressants will significantly aid the transition to ecologically friendly and sustainable processes. This study shows that organic depressants in chalcopyrite flotation can replace the existing inorganic depressants used in the depression of gangue minerals and that metals can be recovered at high performance by processing appropriately. [ABSTRACT FROM AUTHOR]

Sexual harassment is pervasive globally within hospitality organizations. This conceptual study identifies organizational climate characteristics that make the restaurant work environment unique as compared to other industries. The work environment is based upon keeping the customer happy, includes gender gaps in power structures, emphasis on appearances, entrepreneurial in nature, the physical work environment, and alcohol is served. A framework for sexual harassment training must consider organizational factors, pre/post training, design, and evaluation. The study also provides a framework for sexual harassment training given these distinctive esthetics. [ABSTRACT FROM AUTHOR]

When attempting to land on a ship deck tossed by the sea, helicopter pilots must make sure that the helicopter can develop sufficient lift to be able to safely touchdown. This reminder of affordance theory led us to model and study the affordance of deck-landing-ability, which defines whether it is possible to land safely on a ship deck depending on the helicopter's available lift and the ship's deck heave movements. Two groups of participants with no piloting experience using a laptop helicopter simulator attempted to land either a low-lifter or a heavy-lifter helicopter on a virtual ship deck by either triggering a pre-programmed lift serving as the descent law if it was deemed possible to land, or aborting the deck-landing maneuver. The deck-landing-ability was manipulated by varying the helicopter's initial altitude and the ship's heave phase between trials. We designed a visual augmentation making visible the deck-landing-ability, and thus enabling participants to maximize the safety of their deck-landing attempts and reduce the number of unsafe deck-landing. The visual augmentation presented here was perceived by participants as a means of facilitating this decision-making process. The benefits were found to have originated from the clear-cut distinction it helped them to make between safe and unsafe deck-landing windows and the display of the optimal time for initiating the landing. [ABSTRACT FROM AUTHOR]