Problemas con un combo

[cyllan]

$sqlquery="Select servicio,uid from \"td_Servicios\" ORDER BY servicio";
$result = pg_exec($oConexion->bConexion,$sqlquery);
$filas = pg_num_rows($result);

for($i=0;$i<=$filas-1;$i++){
$row=pg_Fetch_Array($result, $i);
$id = $row['uid'];
$cadena=$row['servicio'];

if ($id== $strServicio) {

?>

<option selected value=" <?php $cadena; ?>" ><?php echo $cadena; ?></option>

<?php

}
else{
?>
<option value=" <?php $cadena; ?>" ><?php echo $cadena; ?></option>

<?php
}
}
?>