The Unfolding of the Relational Operant: A Real-time Analysis Using Electroencephalography and Reaction Time Measures

The current study attempted to capture in real time the unfolding of the relational operant using electroencephalography (EEG) and reaction time measures. Participants were exposed to relational pretraining to establish the contextual cues of Same and Opposite for two arbitrary stimuli. These cues were then used to establish a series of contextually controlled discriminations in order to create a simple relational network among a series of arbitrary stimuli. During the test for derived relations of Same and Opposite, EEG and reaction time measures were recorded for each individual test task during the acquisition of a stable derived relational response pattern. Participants were then exposed to an identical set of relational training and testing tasks with the important difference that an entirely different set of stimuli was used. EEG and reaction time measures were again recorded during the relational test phase. Results showed that reaction times decreased for all subjects across successive test tasks and from the first to the second stimulus set. EEG data also suggested that there was increasingly less higher cognitive activity during the derivation of successive stimulus relations within and across stimulus sets. Taken together these findings provide support for the idea that derived relational responding can be viewed as an operant activity that both develops and generalizes

Connection between dynamics and thermodynamics of liquids on the melting line

The dynamics of a large number of liquids and polymers exhibit scaling properties characteristic of a simple repulsive inverse power law (IPL) potential, most notably the superpositioning of relaxation data as a function of the variable TV{\gamma}, where T is temperature, V the specific volume, and {\gamma} a material constant. A related scaling law, TmVm{\Gamma}, with the same exponent {\Gamma}={\gamma}, links the melting temperature Tm and volume Vm of the model IPL liquid; liquid dynamics is then invariant at the melting point. Motivated by a similar invariance of dynamics experimentally observed at transitions of liquid crystals, we determine dynamic and melting point scaling exponents {\gamma} and {\Gamma} for a large number of non-associating liquids. Rigid, spherical molecules containing no polar bonds have {\Gamma}={\gamma}; consequently, the reduced relaxation time, viscosity and diffusion coefficient are each constant along the melting line. For other liquids {\gamma}>{\Gamma} always; i.e., the dynamics is more sensitive to volume than is the melting point, and for these liquids the dynamics at the melting point slows down with increasing Tm (that is, increasing pressure).Comment: 20 pages, 8 figures, 1 tabl

Harvesting Intensity and Aridity Are More Important Than Climate Change in Affecting Future Carbon Stocks of Douglas-Fir Forests

Improved forest management may offer climate mitigation needed to hold warming to below 2°C. However, uncertainties persist about the effects of harvesting intensity on forest carbon sequestration, especially when considering interactions with regional climate and climate change. Here, we investigated the combined effects of harvesting intensity, climatic aridity, and climate change on carbon stocks in Douglas-fir [Pseudotsuga menziesii Mirb. (Franco)] stands. We used the Carbon Budget Model of the Canadian Forest Sector to simulate the harvest and regrowth of seven Douglas-fir stand types covering a 900 km-long climate gradient across British Columbia, Canada. In particular, we simulated stand growth under three regimes (+17%, −17% and historical growth increment) and used three temperature regimes [historical, representative concentration pathways (RCP) 2.6 and RCP 8.5]. Increasing harvesting intensity led to significant losses in total ecosystem carbon stocks 50 years post-harvest. Specifically, forests that underwent clearcutting were projected to stock about 36% less carbon by 2,069 than forests that were left untouched. Belowground carbon stocks 50 years into the future were less sensitive to harvesting intensity than aboveground carbon stocks and carbon losses were greater in arid interior Douglas-fir forests than in humid, more productive forests. In addition, growth multipliers and decay due to the RCP’s had little effect on total ecosystem carbon, but aboveground carbon declined by 7% (95% confidence interval [−10.98, −1.81]) in the high emissions (RCP8.5) scenario. We call attention to the implementation of low intensity harvesting systems to preserve aboveground forest carbon stocks until we have a more complete understanding of the impacts of climate change on British Columbia’s forests

Gambling problems and the impact of family in UK armed forces veterans

Background and aims International evidence indicates elevated problem gambling rates in armed forces veterans compared with the general population. Gambling problems adversely impact one’s family, and family-related variables may increase vulnerability to gambling-related harm. Little is known, however, about gambling problems in the United Kingdom (UK) veterans or to what extent family variables, such as parenting history and experience of domestic violence, influence veterans’ gambling. Methods We compared veterans (n = 257) and sex- and age-matched controls (n = 514) drawn from the 2007 Adult Psychiatric Morbidity Survey on gambling, financial management, domestic violence, childhood parental presence, and experience of stressful life events. Veterans who left the military before or after 4 years of service were compared. Results Problem gambling was significantly more prevalent in veterans (1.4%) than non-veterans (0.2%), and the impact of gambling problems on the family was specific to male veterans, particularly those who had experienced a traumatic event after the age of 16, and those who were more likely to have been physically attacked by their partner. Overall, this study revealed that the UK armed forces veterans report a higher prevalence rate of problem gambling compared with non-veterans, with potential negative impact on family life

Refractive Index of Humid Air in the Infrared: Model Fits

The theory of summation of electromagnetic line transitions is used to tabulate the Taylor expansion of the refractive index of humid air over the basic independent parameters (temperature, pressure, humidity, wavelength) in five separate infrared regions from the H to the Q band at a fixed percentage of Carbon Dioxide. These are least-squares fits to raw, highly resolved spectra for a set of temperatures from 10 to 25 C, a set of pressures from 500 to 1023 hPa, and a set of relative humidities from 5 to 60%. These choices reflect the prospective application to characterize ambient air at mountain altitudes of astronomical telescopes.Comment: Corrected exponents of c0ref, c1ref and c1p in Table