if you had continued with designation of Personal assistant, you would have been defined as a 'workman' under the Industrial Dispute Act. With designation as Scientific Adviser you ceased to do manual/technical/operational work so as to oust you from category of workman though on the basis of nature of duties performed, you can claim to be workman. If you are proved to be covered under definition of workman under ID Act, you will be entitled to retrenchment compensation which is equivalent to 15 days wages for each completed year of service beside notice pay. You don't have any remedy in law if you being in managerial capacity are discharged. I still advise you to issue a notice through a lawyer claiming retrenchment compensation and do raise an industrial dispute on illegal termination of your services in case your notice s not responded to.