WP_Query test

// WP_Query arguments
$args = array (
	'post_type'              => array( 'post', 'publication' ),
	'post_status'            => array( 'publish' ),
	'cat'                    => '4,5',
	'nopaging'               => false,
	'posts_per_page'         => '10',
	'order'                  => 'DESC',
	'orderby'                => 'date',
	'cache_results'          => false,
);

// The Query
$query = new WP_Query( $args );

// The Loop
if ( $query->have_posts() ) {
	while ( $query->have_posts() ) {
		$query->the_post();
		// do something
	}
} else {
	// no posts found
}

// Restore original Post Data
wp_reset_postdata();