résistances

Résistances is the plural of résistance in French and is used across several domains to denote opposition to a process, flow, or influence. In science, technology, biology, and society, resistances describe phenomena that hinder change or transfer, though the underlying causes differ from one field to another. The common thread is the presence of a hindering influence that reduces rate, efficiency, or effectiveness.

In physics and electrical engineering, a resistance is a property that impedes electric current. It is measured in ohms (symbol: Ω). Ohm's law states V = I R, relating voltage, current, and resistance. Resistance depends on material resistivity, temperature, length, and cross-sectional area. When resistors are connected in series, the total resistance adds; in parallel, it decreases. The power dissipated is P = I^2 R = V^2 / R.

In biology and medicine, resistance commonly refers to the reduced effectiveness of drugs, pests, or controls. Antibiotic resistance arises when microbes acquire or exchange genes that neutralize drugs or bypass their effects, sometimes via enzymes, target modification, or efflux pumps. Resistance elevates treatment failure risk, spreads under selective pressure, and poses public health challenges. Mitigation includes prudent use, surveillance, combination therapies, vaccines, and infection-control measures.

In social and political contexts, resistance denotes organized opposition to oppression, occupation, or policy. Civil resistance employs nonviolent actions such as protests, strikes, boycotts, or civil disobedience to pursue change. Throughout history, resistance movements have shaped politics and human rights, from wartime uprisings to contemporary advocacy. The term can also describe cultural or economic resistance to dominant practices.

In mechanics and materials science, resistance can refer to frictional or drag forces opposing motion, or to a material's mechanical resistance to deformation. Aerodynamic or viscous resistance and structural resistance are common usages.