The present study investigated young preschoolers' proportional allocation of rewards in 2 different work contexts. We presented 32 pairs of 3.5-year-old peers with a collaborative task to obtain rewards by pulling ropes. In order to establish differences in work input, 1 child's rope was not immediately accessible but had to be retrieved from the apparatus by means of a specific tool, while th...

laan in (ph.d thesis, tartu. 1999) introduced the principal weak form of condition $(p)$ as condition $(pwp)$ and gave some characterization of monoids by this condition of their acts. in this paper first we introduce condition (g-pwp), a generalization of condition $(pwp)$ of acts over monoids and then will give a characterization of monoids when all right acts satisfy this condition. we also ...

abstract   background: the x-ray machines used for radiodiagnosis should meet certain quality assurance (qa) programmes . these are necessary to have good quality radiographs at reasonably low exposure to patients.   materials and methods: dose reduction methods in abdomen x-ray examination were carried out in 10 hospitals in tehran. this paper presents the work, which was implemented on 200 pa...

an efficient one-pot condensation for the synthesis of 1,8-dioxo-octahydroxanthene is  achieved through a condensation of aryl aldehydes and 5,5-dimethyl-1,3-cyclohexandione in the presence of  nbs. this method enjoys several advantages such as low cost, simple work up procedure and safe reaction condition. in addition, water was chosen as a green solvent.

Friedel–Crafts synthesis of triarylmethanes over 3-methyl-1-sulfonic acid imidazolium tetrachloroaluminate under green conditions:In this work, Friedel–Crafts (FC) alkylation of various arenes with aromatic aldehydes catalyzed by 3-methyl-1-sulfonic acid imidazoliumtetrachloroaluminate {[Msim]AlCl4}, as a green catalyst, to prepare triarylmethanes (TAMs) has been carried out. Some aromatic alde...

background: the aims of this study were to evaluate the employees' subjective assessments of different aspects of lighting condition as well as task area illuminance in manufacturing plants. methods: this field study was conducted between march and may 2013 , in three packing plants (saveh, central iran). data were collected by questionnaire and measurement of the task area illuminance levels. ...

background and purpose: providing health services in health centers is a challenging and risky job. so that, realization of quality, performance, efficiency, and fairness in the provision of such services needs a proper condition to ensure that the stress experienced by the personnel is minimized. the present study is a survey of the factors effective on job stress among the nurses working in t...

abdominal wall hernia is common but reliable scientific data about its work relatedness is very limited and inconsistent. in this paper, a less common type of abdominal wall hernia in a 30 year old male worker is presented with recurrence after first surgery when he returned to work. in contrast with almost all kinds of hernia, a lifelong limitation for heavy lifting was recommended. it seems t...

in this investigation, nano silica chloride (nano sio2cl) has been found to be efficient, chemoselective and recyclable catalyst for facile and simple synthesis of germinal diacetates from aromatic and heteroaromatic aldehydes in shorter reaction durations. the products were obtained in high to excellent yields. this work consistently has the advantages of excellent yields, short reaction time,...