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Forensic Micrscopy
Exactly what it says on the tin
| Term | Definition |
|---|---|
| ISO | International Organization for Standarization |
| ASTM | American Society for Testing and Materials, International |
| ASCLD-LAB | American Society of Crime Lab Directors- Lab Accreditation Board |
| Chain of custody | documentation of location of evidence from the time it is obtained to the time it is presented in court |
| AFTE | Association of Firearms and Toolmarks Examiners |
| Toxicology | chemical analysis of bodily fluid and tissues to determine if a drug or poison is present. |
| Datum | A fixed point of reference for all three-dimensional measurements |
| Artifact | Human-made or modified portable object |
| Feature | Non-portable artifact |
| Matrix | Surrounding material (soil, water, or a living room) |
| Provenance | Origin and deviation of an item in a three-dimensional space, in relation to the datum ad other items |
| Context | The relationship between items and the surroundings where they are found |
| 1. duty of the FO | Detain any potential suspects |
| 2. duty of the FO | Render medical assistance to those who need it |
| 3. duty of the FO | Do not destroy, alter, or add evidence at the scene |
| 4. duty of the FO | Prevent others, even superiors, from mucking with the evidence |
| MSDS | Material Safety Data Sheet |
| Universal Precautions | Require employees to treat all human blood, body fluids, and other materials as if they are infected |
| Evidence | Information that is given in a legal investigation to make a fact or proposition seem more or less likely |
| Trier-of-fact | Whoever determines the guilt of innocence |
| Proxy data | Remnants of events left behind |
| Demonstrative evidence | Prepared later to help the trier-of-fact understand complex testimony |
| Conclusive evidence | Evidence so strong as to overbear any other evidence to the contrary |
| Cirscumtantial evidence | Evidence based on inference and not personal knowledge or observation |
| Conflicting evidence | Irreconcilable evidence that comes from different sources |
| Corroborating evidence | Evidence that differs from but strengthens or confirms other evidence |
| Derivative evidence | Evidence that is discovered as a result of of illegally obtained evidence and is therefore inadmissible because of the primary taint |
| Exculpatory evidence | Evidence tending to establish a criminal defendant's innocence |
| Foundational evidence | Evidence that determines the admissibility of other evidence |
| Hearsay | Testimony that is given by a witness who relates what others have said |
| Incriminating evidence | Evidence tending to establish guilt or from which a fact-trier can establish guilt |
| Presumptive evidence | Evidence deemed true and sufficient unless discredited by other evidence |
| Prima facie evidence | Evidence that will establish a fact or sustain a judgement unless contradictory evidence is produced |
| Probative evidence | Evidence that tend to prove or disprove a point in issue |
| Rebuttal evidence | Evidence offered to disprove or contradict the evidence presented by the opposing party |
| Tainted evidence | Evidence that is inadmissible because it was directly or indirectly obtained by illegal means |
| Direct transfer | Transferred from object A to object B |
| Indirect transfer | Involves one or more intermediate objects |
| Contamination | Any transfers that take place after the action surrounding the crime has stopped |
| Class | Group of objects with similar characteristics |
| Questioned evidence | Evidence for which the original source is unknown |
| Known evidence | Evidence for which the original source is known |
| Coincidental Associations | Two things which have previously never been in contact with each other have items on them which any anatomically indistinguishable at a certain class level |
| Type I error | False positive, saying something is blood when it is not |
| Type II error | False negative, saying something is not blood when it is |
| Simple magnification system | A single lens used to form an enlarged image of an object |
| Compound magnification system | Magnification occurs in two stages |
| Lens | Material that bends light in a known and predictable manner |
| Focal length | Distance between two points of focus on either side of the lens |
| Resolution | Minimum distance two things can be separated and still be distinguished as two objects (d=λ/2NA) |
| Numerical aperture | Angular measure of the lens' light-gathering ability (NA=nsinμ) μ being half the angle of aperture of the objective |
| Eyepiece/ocular | Lens that an observer looks into |
| Field of view | The area seen through the eyepieces |
| 10x/0.25na/170mm/0.17Plan Apo | 10 times magnification, 0.25 numerical aperture, 170mm tube length, 0.17mm recommended coverslip thickness, plan apochromat corrected |
| Condenser | Used to obtain a bright, even field of view and improve image resolution |
| Kohler illumination | Sets light rays parallel throughout the lens system |
| Refractive index | N = c/v, where c is the speed of light in a vacuum (186000 miles per second) and v is the speed of light in the material |
| Snell's Law | n1sinθ1=n2sinθ2 |
| Isotropic | Optically the same throughout, only one refractive index |
| Anisotropic | Optical properties that vary with orientation of incoming light, has an ordinary and extraordinary ray |
| Birefringence | Division of light into the ordinary and extraordinary ray when it passes through certain types of material (n=ne-no) |
| Fluoresence | The luminescence of a substance excited by radiation, emission stops when the excitation stops |
| Phosphorescence | Characterized by long-lived emission |
| TEM | Transmission electron microscope |
| SEM | Scanning electron microscope |
| Electromagnetic radiation | Various types of energy in the form of waves |
| Wavelength | Distance between corresponding points on two adjacent waves (c=λ/v) where c is the speed of light, λ is the wavelength, and v is the frequency |
| Frequency | The number of waves that pass a given point in one second |
| Photon | Tiny packets of energy (E=hv or hc/λ) |
| Electromagnetic spectrum | High energy. Gamma, X-rays, Ultraviolet, Visible, Infared, Microwave, Radio. Low energy |
| Microspectrophotometry | Used for comparing colors, measures UV and visible light spectra |
| Beer's Law | Relates the amount of absorbing substance present to the quantity of absorbance of light |
| Analyte | Substance or substances being identified |
| Solvent | Liquid or liquid solution that is used to dissolve an analyte |
| Solute | Substance that is dissolved in a solvent |
| Partitioning | Competition of two solvents for an analyte |
| Adsorption | Process whereby a solid, liquid or gaseous analyte is attracted to the surface of a dissolving molecule |
| Gas chromatography | The most versatile form of chromatography |
| Electrophoresis | Type of chromatography that relies on the role of an electric field |
| Hairs | Fibrous growths that originate from the skin of mammals |
| Epidermis | Outer layer of the skin |
| Follicle | Structure within which hairs grow |
| Keratin | Tough, protein-based material from which hairs, nails, and horns are made |
| Keratinization | Hardening process of hair growth |
| Sebaceous glands | In the follicle, produces oils that coat hairs helping to keep them soft and pliable |
| Pili arrector | Tiny muscles that raise hairs |
| Anagen | First stage of hair growth, follicle produces new cells |
| Catagen | Second stage of hair growth, follicle begins to shut down production of cells |
| Melanin/Pigment | Small coloured granules that give hairs their particular color |
| Melanocytes | Specialized cells that produce melanin/pigment |
| Eumelanin | Dark brown pigment |
| Pheomelanin | Lighter pigment |
| Root bulb/club root | Root condenses into this during the catagen phase of hair growth |
| Telogen | Resting phase for hair growth, root is held in place only by a mechanical connection |
| Root | Portion that was formerly in the follicle |
| Tip | Distal-most portion of the hair |
| Shaft | Main portion of the hair |
| Cuticle | Series of overlapping series of scales that forma protective covering |
| Imbricate | Human scale pattern |
| Cortex | Structure that makes up the bulk of the hair |
| Cortical fusi | Small bubbles that may appear in the cortex |
| Ovoid bodies | Odd structures that look like large pigment granules and may appear irregularly in the cortex |
| Guard hairs | Large stiff hairs that make up the outer part of an animal's coat |
| Shield | Widening in guard hairs in the upper half of the shaft |
| Buckling | Abrupt change in direction of the hair shaft with or without a slight twist |
| Shouldering | Asymmetrical cross-section of hairs |
| Pili annulati | Hairs with colored rings |
| Monilethrix | Makes hairs look like strings of beads |
| Pili torti | Twisting of the hair along its length, creating a spiral morphology |
| Natural fiber | Any fiber that exists as a fiber in its natural state |
| Manufactured fiber | Any fiber derived by a process of manufacturing from any substance that, at any point, is not a fiber |
| Filaments | Type of fiber having indefinite or extreme length |
| Staple fibers | Natural fibers or cut lengths of filament 7/8 in - 8 in |
| Denier | Weight in grams of 9000 m of the material fibrous |
| Yarn | Term for continuous strands of textile fibers, filaments, or material in a form suitable for entangling to form a textile fabric |
| Plied yarn | Yarn composed of several smaller strands of yarn twisted together |
| Fabric | Textile structure produced by interlacing yarns, fibers, or filaments with substantial surface area relative to its thickness |
| Synthetic fibers | Manufactured fibers that are synthesized from a chemical compound |
| Soil | Contains both organic (humus) and inorganic (crushed rock and clay) material |
| Glass | Amorphous solid, usually transparent |
| Coatings | Any surface coating designed to protect, aesthetically improve, or provide some special quality, coloquially: paint |
| Paint | Suspension of pigments and additives designed to color of protect a surface |
| Binder | That portion of the coating that allows the pigment to be distributed across the surface |
| Vehicle | Solvents, resins, and other additives that form a continuous film, binding the pigment to the surface |
| Microtome | A device that holds a sample in place while a heavy and very sharp knife slices off sections a few tens of microns thick |
| Bertillonage | First system of identification, used anthropometric measurements |
| Friction ridges | Leave fingerprints, found on the palms, soles, and ends of fingers and toes |
| Patent print | Fingerprint in some medium, blood, clay, fresh paint |
| Latent print | Composed of the sweat and oils of the body that are transferred from the ridge pattern to some substrate |
| Minutiae | Ridge characteristics |
| Loop | One or more ridges entering from one side, curving back on themselves, and exiting the fingertip on the same side |
| Arch | Ridges enter the print, gradually rise, and exit the opposite side |
| Tented Arch | Arches with a pronounced sharp peak |
| Whorl | Have type lines and at least two deltas, can be plain, central pocket, double loop, and accidental |
| AFIS | Automated Fingerprint Identification System |
| Exemplar | Known, authentic writing sample |
| Requested writing | Writing samples taken from someone for the purpose of comparison with a questioned document |
| Non-requested writing | Examples of subject's writing taken in the normal course of personal or business transactions |
| Formal signature | Written carefully on an official document, name is not in doubt |
| Informal signature | Used in routine correspondence where you want the person to recognize the name but the spelling isn't important |
| Stylistic signature | Used in signing checks, credit card receipts, looks like a scribble |
| Document alterations | Obliterations, erasures, additional markings, indented writings, and charred documents |
| Obliteration | Overwriting of a sample of writing or printing with another writing instrument |
| Abrasive erasure | Removing writing with an abrasive eraser material |
| Chemical erasure | Dissolving or bleaching ink so it is no longer visible |
| Indented writing | An image of the writing on one or more pages below |
| ESDA | Electrostatic Detection Apparatus |
| Rifling | Series of lands and grooves down the inside of a gun barrel |
| Striations | Impressions of the interior barrel surface made on a bullet as it passes through the gun |
| Bore | Diameter of a circle that touches the tops of the lands |
| Caliber | Refers to the size of a particular ammunition cartride |
| Gauge | Diameter of the shotgun barrel |
| Firing pin impression | Mark made by the firing pin as it strikes the primer cap |
| Extraction/Ejection marks | Marks indicative of the method of cartridge extraction or ejection |
| Trigger pull | The force required to pull the trigger to the firing position |
| Gunshot residue | Cloud of molten metals, partially burned gunpowder flakes, smoke, and other microscopic debris expelled when the gun fires |
| Footwear impression | When a piece of footwear comes into contact with a recipient material or object |
| Imprint | Made when there is enough residue to leave an impression on the recipient surface |
| Frye | General acceptance within the particular scientific field to which it belongs |
| Daubert | Falsifiability, knowledge of error rates, peer review, general acceptance, general acceptance |
Created by:
Dragoness
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