We present the three main mathematical constructs used to represent the attitude of a rigid body in threedimensional space. These are (1) the rotation matrix, (2) a triple of Euler angles, and (3) the unit quaternion. To these we add a fourth, the rotation vector, which has many of the benefits of both Euler angles and quaternions, but neither the singularities of the former, nor the quadratic ...

Many cities in the Global South are structurally different from Northern, particularly American, on which much of urban sociology’s conceptual apparatus has been based. Thus, depicting them terms a standard vocabulary risks imposing an inappropriate way seeing. We need that is able to accommodate their experience. This special issue contributes work building vocabulary. select five keywords soc...

Background: Prenatal care plays an important role in the reduction of the maternal and infant mortality rates. This study was conducted in order to assess the level of knowledge, attitude and practice of prenatal care among women in Rafsanjan. Materials and Methods:  This descriptive and cross-sectional study was done in the year 2000.  The KAP eas determined by interviewing 642 women during t...

When we meet an emotion keyword in a sentence that expresses a kind of emotion, or a word that does not directly express emotion but carries an attitude clue, it could be the case that the speaker is just stating a truth without any affection; it could be an expression of attitudes or emotive states of the agent but using different ways, or it could be other cases. In this case, it seems doubta...

dadresanfar b 1 ehsani m 2 vallaee n 3 khalilak z #1   1- assistant professor, endodontic dept, islamic azad university, dental branch, tehran, iran   2-dentist   3- faculty member of islamic azad university, dental branch   corresponding author: khalilak z: endodontic dept, no 4 , 10th neyestan ave, pasdaran. tehran iran   tel: 0 21 22564571-3 email: dr.z.khalilak@ gmail.com  background and ai...