Contingency learning tracks with stimulus-response proportion no evidence of misprediction costs

We investigate the processes involved in human contingency learning using the color-word contingency learning paradigm. In this task, participants respond to the print color of neutral words. Each word is frequently presented in one color. Results show that participants respond faster and more accurately to words presented in their expected color. In Experiment 1, we observed better performance for high-relative to medium-frequency word-color pairs, and for medium-relative to low-frequency pairs. Within the medium-frequency condition, it did not matter whether the word was predictive of a currently-unpresented color, or the color was predictive of a currently-unpresented word. We conclude that a given word facilitates each potential response proportional to how often they co-occurred. In contrast, there was no evidence for costs associated with violations of high-frequency expectancies. Experiment 2 further introduced a novel word baseline condition, which also provided no evidence for competition between retrieved responses

Is Water Shedding Next?

South Africa is in the grip of an electricity crisis marked by a euphemism known as “load shedding”. The demand for electricity has grown to the point that the supply reserve margin is often under threat, necessitating the electricity supplier to cut supply to some areas for various periods of time, or to shed load. This is a condition previously unknown to South Africa since the country has enjoyed electricity security from the mid-1950s. Are we, however, heading in the same direction when considering water? Is water shedding inevitable? We ask these questions since South Africa is a country classified has having chronic water shortages, a condition exacerbated by climate change and the rapidly increasing demand for water. Can we avert a water shedding crisis by being proactive? In this paper we address this issue by applying a Computable General Equilibrium (CGE) model using an integrated database comprising South Africa’s Social Accounting Matrix (SAM) and sectoral water use balances. We refer to AsgiSA, the governments’ Accelerated and Shared Growth Initiative in South Africa, and conclude that continuing business as usual will indeed lead to a situation where water shedding will be inevitable. Unlike electricity, however, water security is much more serious from livelihood, health and socio-economic development perspectives since there are no substitutes for it, although its influence is not directly and immediately visible. This delayed effect can create a degree of comfort and ill-founded complacency leading to non-action, whereas there is an urgent need for proactive measures.

Geometric modeling for computer-aided design

Software was developed to be used with the derivation of smooth three dimensional surfaces from a sequence of cross sections. Problems arising in the creation of surfaces by extrusion are considered and calculated physical properties are presented

Does graded return to work improve disabled workers’ labor market attachment?

Using Danish register and survey data, we examine the effect of a national graded return-to-work program on the probability of sick-listed workers returning to regular working hours. During program participation, the worker receives the normal hourly wage for the hours worked and sickness benefit for the hours off work. When the worker’s health improves, working hours are increased until the sick-listed worker is able to work regular hours. Taking account of unobserved differences between program participants and non-participants, we find that participation in the program significantly increases the probability of returning to regular working hours.