Determining whether a stain contains blood. Establishing blood, identifying a species and identifying an individual are separate analytical questions requiring different evidence.^[ref]

Evidence that an injury occurred while biological reactions were still possible. Inflammation and other tissue responses can inform assessment, but decomposition and timing limit the inference from any single marker.^[ref]

Comparison of variable regions of DNA for identity or relatedness investigations.

Post-mortem pooling of blood in dependent body regions. Its appearance must be distinguished from a living response to injury.

Decomposition of organic material, including changes to a body after death that can complicate assessment of wound vitality.

Historical medico-legal assessment of reported sexual violence. Medical observations do not independently determine consent; older resistance and virginity assumptions must be distinguished from current evidence.

Assessment of skeletal remains using anatomical and other evidence to support identification. Estimates of age, sex or stature are probabilistic characterizations; agreement with a profile is different from individual identification.^[ref]

Medical investigation of a newborn body to address questions such as injury, development and evidence of life after birth. No single sign, including lung flotation, reliably replaces interpretation of the whole examination.^[ref]

A route into a vein through which fluids or medicines can be delivered or samples obtained. Establishing access creates a delivery pathway; it is distinct from deciding which substance or amount is appropriate.

Fluid administered directly into a vein. Its constituents, concentration and volume determine effects on blood circulation and electrolyte balance, so equal volumes of different solutions are not physiologically interchangeable.^[ref]

A floating density instrument. At equilibrium, Archimedes' principle gives $\rho V_{\mathrm{displaced}}=m$ for fixed instrument mass $m$, so it displaces more volume in a less dense liquid. A graduated narrow stem converts this volume change into a visible immersion reading. Calibration specifies a temperature and a reading convention for the meniscus; a sample's other dissolved substances can affect a sugar-calibrated scale.

For a phase occupying area $\alpha A$ of a constant-area pipe, define $\bar{\rho }=(\alpha A{)}^{-1}\int \rho dA$, $\bar{v}=\int \rho vdA/(\alpha A\bar{\rho })$ and $\overline{v^2}=\int \rho v^{2}dA/(\alpha A\bar{\rho })$. The momentum per length is $A\alpha \bar{\rho }\bar{v}$, the advected momentum flux is $A\alpha \bar{\rho }\overline{v^2}$, and end pressures contribute $-A{\partial }_x(\alpha \bar{p})$. Applying Newton's second law to a slice proves the displayed balance, with $M$ all other phase forces per length. Interphase pressure terms can cancel the derivative of the area fraction. Equality of the second moment and squared mean requires a separate closure.

The hydraulic radius is cross-sectional flow area divided by wetted perimeter. A perimeter-averaged boundary shear stress $\tau$ exerts drag per unit fluid volume $\tau \ell /A=\tau /R$. It differs from both actual depth and the radius of a noncircular channel.

The Chézy law relates mean open-channel speed to hydraulic radius and energy slope through a friction coefficient. Equivalently one can use bed shear ${\tau }_b=\rho fu|u|$; for positive uniform flow, balance $\rho gAI={\tau }_b{P}_b$ gives $u=\sqrt{gI/f}\sqrt{A/P_b}$. The absolute value makes drag oppose motion if reverse flows are admitted.

For a pipe of area $A$, let a phase indicator function be $\chi$. Define $\alpha =A^{-1}\int \chi dA$, $\bar{\rho }=(A\alpha {)}^{-1}\int \chi \rho dA$ and the mass-weighted axial velocity $\bar{u}=(A\alpha \bar{\rho }{)}^{-1}\int \chi \rho u_{x}dA$. Without interfacial mass transfer, integrate ${\partial }_t(\chi \rho )+\nabla \cdot (\chi \rho \mathbf{u})=0$ over a cross-section with impermeable lateral wall. The resulting averaged mass and flux are exactly $\alpha \bar{\rho }$ and $\alpha \bar{\rho }\bar{u}$, proving the displayed law. The complementary phase uses $1-\chi$ and $1-\alpha$. An unweighted phase velocity would not generally factor the mass flux correctly.

A flow containing two or more distinguishable material phases, such as two immiscible liquids or a gas-liquid mixture. Each phase can have its own volume fraction, density and velocity. Cross-sectional or ensemble averaging produces coupled phase balance equations whose mass, momentum and energy exchange terms must be specified consistently. A common pressure alone does not automatically make an averaged model well posed.

Move file contents to consolidate their allocated regions. A per-file read-then-write cost model charges two transfers and, if specified, two separate seek and rotation overheads for each moved file. That model differs from an ideal sequential transfer of the same total number of bytes.

A disk block number identifies a fixed-size storage region on a volume. It locates storage rather than naming a file. A file can occupy several numbered file data blocks, while a disk block containing several inodes can describe several files.

A representation of currently unallocated disk block numbers, maintained as a list or linked groups of available numbers. Allocation removes a number; deallocation returns it after ownership is relinquished. Reserved structures and blocks still owned by an unnamed but open file are unavailable. A block allocation bitmap is an alternative representation of the same allocation state.

Allocated space unused inside an allocation unit. For a computer file stored in fixed-size file data blocks, the final partially occupied block can waste almost one block.