A central cholinergic inhibitory system as a basis for tonic immobility (animal hypnosis) in chickens.

4 experiments provided support for the hypothesis that tonic immobility (TI) in chickens, which may be analogous to response suppression in the rat, is a result of fear and is mediated by central cholinergic systems. A total of 124 experimental and 54 control, White Leghorn cockerel chicks were the Ss. Exp I established that scopolamine, a central and peripheral acting anticholinergic, will reduce the duration of TI, whereas methylscopolamine, which acts only peripherally, will not. Exp II established a dose-response curve for scopolamine and TI. Exp III demonstrated that scopolamine increased activity and that this increase may be a factor in reducing the duration of TI. Exp IV showed that physostigmine, which blocks acetylcholinesterase and allows longer action of acetylcholine at the synapse, increased the duration of TI. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Use of multiwavelength transmission spectroscopy for the characterization of Cryptosporidium parvum oocysts: quantitative interpretation

Combined scattering and absorption properties of suspended particles can be obtained as a function of wavelength by measuring the complete ultraviolet-visible (UV-vis) spectrum. This research reports on the quantitative interpretation of measured UV-vis spectra of Cryptosporidium parvum oocyst suspensions obtained from several commercial sources and evaluated using two different purification techniques. The reproducibility of the measured spectral data was assessed, and the quantitative interpretation of the oocyst spectra in terms of the particle size and the chemical composition of the particles are reported herein. The interpretation model of the spectra is based on light scattering theory, spectral deconvolution techniques, and on the approximation of the wavelength-dependent optical properties of the basic constituents of living organisms. A characteristic set of optical properties for C. parvum oocysts has been determined as a function of wavelength and used for the quantitative interpretation of UV-vis spectra. The results from the spectral deconvolution show quantitative differences among oocyst preparations. These results represent the first step in establishing a set of critical parameters (e.g., oocyst size and chemical composition) necessary for the detection and identification of C. parvum oocysts in water using spectroscopy.     

Passive in situ remediation of metal-polluted water with caustic magnesia: evidence from column experiments

Passive remediation consists of a permeable system that enables the water to pass through while retaining metals by means of biogeochemical reactions. Conventional passive treatments are based on calcite dissolution. This increases the pH to values between 6 and 7, which are insufficiently high to precipitate divalent metals. Alternative treatments are based on sulfate reduction with organic matter in order to precipitate metal sulfides. However, redox reactions are usually too slow to treat large groundwater flows as currently found in gravel aquifers (>50 m/a). Caustic magnesia obtained from calcination of magnesium carbonate was tested as an alternative material to devising passive remediation systems. Caustic magnesia reacts with water to form magnesium hydroxide, which dissolves, increasing the pH to values higher than 8.5. Then zinc and lead are mainly precipitated as hydroxides, copper is precipitated as hydroxysulfate, and manganese(II) is oxidized and precipitated as manganese(III) oxides. Thus, metal concentrations as high as 75 mg/L in the inflowing water are depleted to values below 0.04 mg/L. Magnesia dissolution is sufficiently fast to treat flows as high as 100 m/a. The new precipitates may lead to a permeability drop in the porous treating system. Mixtures of caustic magnesia and an inert material such as silica sand (approximately 50% of each) have been shown to be as reactive as pure magnesia and permeable for a longer time (more than 10 months and 1000 pore vol).     

Greetings and Closings in Workplace Email

This article reports on a study of the use and form of greetings and closings in the emails of two New Zealand workplaces: an educational organization and a manufacturing plant. Using discourse analytic techniques, 515 emails were analyzed and a number of differences were identified. In the educational organization, where restructuring has resulted in low staff morale and a mistrust of management, indirect and socially distant styles of communication prevailed and greetings and closings were not widely used. In the manufacturing plant, the more extensive use of greetings and closings reflected and constructed the open and positive relationships between staff and management and the direct, friendly, and familial workplace culture. The findings suggest that workplace culture is a more important factor accounting for the frequency and form of greetings and closings than are relative status, social distance, and gender.     

Temperature and emissivity separation from ASTER data for low spectral contrast surfaces

The performance of Advanced Spaceborne Thermal Emission Reflection Radiometer (ASTER) thermal infrared (TIR) data product algorithms was evaluated for low spectral contrast surfaces (such as vegetation and water) in a test site close to Valencia, Spain. Concurrent ground measurements of surface temperature, emissivity, and atmospheric radiosonde profiles were collected at the test site, which is a thermally homogeneous area of rice crops with nearly full vegetation cover in summer. Using the ground data and the local radiosonde profiles, at-sensor radiances were simulated for the ASTER TIR channels and compared with L1B data (calibrated at-sensor radiances) showing discrepancies up to 3% in radiance for channel 10 at 8.3 μm (equivalently, 2.5 °C in temperature or 7% in emissivity), whereas channel 13 (10.7 μm) yielded a closer agreement (maximum difference of 0.5% in radiance or 0.4 °C in temperature). We also tested the ASTER standard products of land surface temperature (LST) and spectral emissivity generated with the Temperature-Emissivity Separation (TES) algorithm with standard atmospheric correction from both global data assimilation system profiles and climatology profiles. These products showed anomalous emissivity spectra with lower emissivity values and larger spectral contrast (or maximum-minimum emissivity difference, MMD) than expected, and as a result, overestimated LSTs. In this work, a scene-based procedure is proposed to obtain more accurate MMD estimates for low spectral contrast materials (vegetation and water) and therefore a better retrieval of LST and emissivity with the TES algorithm. The method uses various gray-bodies or near gray-bodies with known emissivities and assumes that the calibration and atmospheric correction performed with local radiosonde data are accurate for channel 13. Taking the channel 13 temperature (atmospherically and emissivity corrected) as the true LST, the radiances for the other channels were simulated and used to derive linear relationships between ASTER digital numbers and at-ground radiances for each channel. The TES algorithm was applied to the adjusted radiances and the resulting products showed a closer agreement with the ground measurements (differences lower than 1% in channel 13 emissivities and within ± 0.3 °C in temperature for rice and sea pixels).     

Sliding mode control based buck-boost bidirectional converter to drive piezoelectric loads

The present work deals with the development of a converter to drive piezoelectric actuators to be used in automotive and aerospace applications and work under mechanical frequencies up to 2 kHz with rectangular, triangular and sinusoidal reference signals. In order to maximize the field in the piezoelectric ceramic important voltages (up to 2,000 V) are needed. To fulfill such requirements with a limited input voltage a bidirectional buck-boost converter is proposed. Such a converter shows voltage reduction and elevation capability. This advantage overcomes its intrinsic control non-linearity and the drawbacks involved. The converter is controlled by means of a sliding mode control strategy based on two different linked sliding surfaces which are defined as the energy error of the converter for charging and discharging operation modes, so that each surface controls one of the two switches employed. The state-space evolution of the voltage and current is investigated in order to analyze the converter limitations. The proposed converter and control strategy have been simulated and have proved to be appropriate and robust for different voltage references and values of the equivalent capacitance C _P .     

Ab initio insights into the visible luminescent properties of ZnO

The luminescence spectrum of ZnO exhibits, besides a UV band-edge recombination line, a broad visible band around 2.2-2.4 eV whose origin has not been satisfactorily established. Recently, analysis of the luminescence of nanostructured materials with high surface-to-volume ratios has led some authors to suggest that the band could be related to surface states. This work presents a novel ab initio study of the most relevant ZnO surfaces and their intrinsic point defects. It reveals the existence of intragap surface states 0.5 eV above the valence band maximum. If additional bulk defect levels are considered, several bulk-to-surface transitions are compatible with the observed visible luminescence.     

Assessing Counter-Terrorism field training with multiple behavioral measures

Development of behavioral pattern recognition and analysis skills is an essential element of Counter-Terrorism training, particularly in the field. Three classes of behavioral measures were collected in an assessment of skill acquisition during a US Joint Forces Command-sponsored course consisting of Combat Tracking and Combat Profiling segments. Measures included situational judgment tests, structured behavioral observation checklists, and qualitative assessments of the emergence of specific knowledge–skills–attitudes over the course of the training. The paper describes statistical evidence across the three types of measures that indicate that behavioral pattern recognition and analysis skills were successfully acquired by most students (a mix of Army and civilian law enforcement personnel) during the field training exercises. Implications for broader training of these critical skills are also discussed.     

Capsosomes with Multilayered Subcompartments: Assembly and Loading with Hydrophobic Cargo

Therapeutic artificial cells or organelles are nanoengineered vehicles that are expected to substitute for missing or lost cellular function. The creation of capsosomes, polymer carrier capsules containing liposomal subcompartments, is a promising approach towards constructing such therapeutic devices using the layer‐by‐layer assembly method. Herein, the assembly of intact, nonaggregated capsosomes containing multiple liposome layers is reported. It is also further demonstrated that thiocoraline, a hydrophobic model peptide with antitumor activity, can be efficiently loaded into the membrane of the liposomal subcompartments of the capsosomes. Cell viability assays verify the activity of the trapped antitumor cargo. It is also shown that pristine capsosomes do not display inherent cytotoxic effects. The ability to tune the number of liposome layers and hence the drug loading in capsosomes as well as their noncytotoxicity provide new opportunities for the creation of therapeutic artificial cells and organelles.