teacher responsibility for student success, an optimistic and comprehensive teacher and mentor role, teacher persistence with all students, and an optimism that all students can learn. Others have been equally persuasive in observing that the quality of teacher-student relationships, the atmosphere and tone of classrooms and the overall impact of positive classroom environments is an essential feature of an effec- tive management program (Darling-Hammond, 1997; Koegel, Koegel \& Dunlap, 1996; Skiba \& Rausch, 2006). Berliner (1985) observed that positively and clearly com- municating academic work expectations, programming for student success, and developing a hospitable and welcom- ing atmosphere bode well for all students and thus should be used to positively influence school and classroom climate. However, he sagely noted that although such conditions are essential they are not sufficiently powerful to eliminate the need for other management programs. As previously noted, an organized and structured envi-

1. Un esquema de los regímenes tributarios. 2. Un mapa conceptual de los tipos de contribuyentes. 3. Un esquema del impuesto al valor agregado. 4. Un esquema del impuesto a las transacciones.

Una ambulancia lleva una velocidad de \( 23 \mathrm{~m} / \mathrm{s} \) y su sirena suena con frecuencia de 875 Hertz. ¿Qué frecuencia aparente escucha un observa que está parado cuando:

Enunciado: La pendiente de la grafica \[ 3\left(x^{2}+y^{2}\right)^{2}=100 x y \] en el punto \[ (3,1) \]

EXERCICE 03 1) Montrer que si \( a \) est un nombre paire et \( b \) un nombre impaire alors \( 3 a+2 b \) est un multiple du 6 2) a- montrer que pour tout \( n \in N \), le nombre \( n(n+1)(n+2)(n+3) \) Est un multiple de 4. b- est qu'il existe un entier naturel \( n \) tel que \( n(n+1)(n+2)(n+3)=2010 \) ?

A New York Times/Kaiser foundation survey of Chicagoans showed that they are deeply dissatisfied with the direction of their city, distrustful of their police force, and divided along racial lines. The poll is based on telephone interviews conducted April 21 -May 3,2016 , with 1123 adults who live in Chicago. The samples of telephone exchanges for both landlines and cell phones were randomly selected by a computer from a complete list of exchanges in Chicago (the telephone exchange is the three digits following the area code). Within each exchange, random digits were added to form a complete telephone number, thus permitting access to listed and unlisted numbers alike. Landline respondents are chosen at random within each household on the basis of which member had the most recent birthday, Are there residents of Chicago who have telephone numbers that cannot be reached by the survey method described? Why could this could be a problem? a. Yes, many residents may not be reached because the survey method is randomizing telephone numbers to call. This could potentially bias the results. b. No, the survey method is sufficient in collecting information about the adult residents in Chicago beciuse they are getting a representative sample of adults through the randomizing of telephone numbers. There is no potential bias. c. Yes, many residents may not be reached. A resident who initially received a cell phone number while living in a different geographical region will have an eachange that is not a Chicago exchange. This could potentially bias the results. None of the choices are correct.