Added nexus usage diagrams and updated Introduction_nexus_en.md

docs/slides/Introduction_nexus_en.md

@@ -61,7 +61,7 @@ pandoc-latex-fontsize:
 Virtual desktop infrastructure (VDI) developed at ISC
 
 - PC-based *live* exams **without the possibility of cheating**.
-- Personalized** environments for labs/exercises/practicals
+- **Personalized** environments for labs/exercises/practicals
 - Usable by **any teacher**
 - Virtual machines and access rights **highly configurable**
 - Accessible from the **outside** via VPN
@@ -108,7 +108,7 @@ The day of the exam :
 
 \small
 
-1. Teacher provides each student with a laptop textsuperscript{*}
+1. Teacher provides each student with a laptop\textsuperscript{*}
    - \footnotesize starts automatically on Nexus-exam via wired network (or HES-GE wifi) or dedicated USB key
 1. Teacher provides each student with credentials (paper)
 1. Student logs into their VM using their credentials and does the exam
@@ -154,15 +154,24 @@ When the teacher is ready to grade the exams :
 
 
 [//]: # ----------------------------------------------------------------
-## Assessment after a year
+## Assessment so far
 
-- Nexus used **\textcolor{mygreen}{successfully}** in *live* exams at ISC from October 2022 to June 2023
+- Nexus is being used **\textcolor{mygreen}{with great success}** for *live* exams at ISC since October 2022
 
 \vspace{.5cm}
 
 \centering
 ![](images/thumb_up.png){ width=50% }
 
+[//]: # ----------------------------------------------------------------
+## Nexus resource usage
+
+\footnotesize
+Use case below: 45 VMs (2 vCPUs, 3.5GB RAM)
+
+![](images/resources_usage_45vms_2vcpus_3500ram.png){ width=100% }
+
+
 [//]: # ----------------------------------------------------------------
 ## Future improvements