diff --git a/app/controllers/seminars_controller.rb b/app/controllers/seminars_controller.rb
index 9a6e0e2..5fac0fc 100644
--- a/app/controllers/seminars_controller.rb
+++ b/app/controllers/seminars_controller.rb
@@ -40,7 +40,7 @@ class SeminarsController < ApplicationController
 
     seminar = SeminarMain.find_by(uid: params[:uid])
 
-    if !seminar.registration_status.blank? and seminar.signup_start_date <= time_now and ( seminar.signup_end_date.nil? or  seminar.signup_end_date+1 >= time_now )
+    if !seminar.registration_status.blank? && seminar.signup_start_date <= time_now && ( seminar.signup_end_date.nil? ||  seminar.signup_end_date+1 >= time_now )
       sign_up = ('<a href="'+ OrbitHelper.url_to_show(seminar.to_param) + '" target="_blank">' + t('seminar.signup') + '</a>').html_safe
     elsif seminar.registration_status.blank?
       sign_up = t('seminar.sign_up_not_open')
@@ -50,9 +50,9 @@ class SeminarsController < ApplicationController
       sign_up = t('seminar.sign_up_overdue')
     end
 
-    if !seminar.registration_status.blank? and seminar.registration_status.include?('C') and seminar.contribute_start_date <= time_now and ( seminar.contribute_end_date.nil? or seminar.contribute_end_date+1 >= time_now )
-      if !session[:seminar_signup_id].blank? 
-        if session[:seminar_main_id] == seminar.id
+    if !seminar.registration_status.blank? && seminar.registration_status.include?('C') && seminar.contribute_start_date <= time_now && ( seminar.contribute_end_date.nil? || seminar.contribute_end_date+1 >= time_now )
+      if !@@session[:seminar_signup_id].blank? 
+        if @@session[:seminar_main_id] == seminar.id
           contribute_action = ('<a href="'+ OrbitHelper.url_to_show(seminar.to_param) + '?method=con_upload">' + t('seminar_signup.uploads') + '</a>').html_safe
         else
           contribute_action = ('<a href="'+ OrbitHelper.url_to_show(seminar.to_param) + '?method=con_login">' + t('seminar_signup.con_login') + '</a>').html_safe