Logical evaluation of evidence when a person is suspected of committing two separate offences.

We consider the problem of drawing inferences within a legal framework when a person is a suspect for two separate offences. Although we are primarily concerned with scientific evidence the issue inevitably arises as to how that evidence interacts with other, non-scientific evidence. We show that, in this particular context, the evidence can be conveniently classified into three categories that concern, respectively: the first crime only; the second crime only; and evidence that relates to similarities between the two crimes. Two case examples are considered and we consider DNA, fibres and eyewitness evidence. These are viewed from the perspective of a prosecutor who has to decide whether or not to charge a suspect with one or both crimes. Graphical sensivity analyses are presented which have features that are not intuitively obvious.

Effects of beach sand properties, temperature and rainfall on the degradation rates of oil in buried oil/beach sand mixtures.

Lysimeters located outdoors have been used to evaluate the decomposition of buried oily beach sand waste (OBS) prepared using Forties light crude oil and sand from different locations around the British coast. The OBS (5% oil by weight) was buried as a 12-cm layer over dune pasture sub-sand and overlain by 20 cm of dune pasture topsoil. Decomposition rates of oil residues averaged 2300 kg ha(-1) in the first year and the pattern of oil decomposition may be represented by a power curve. Oil decomposition was strongly related to the temperature in the OBS layer, but was also significantly affected by rainfall in the previous 12 h. The CO(2) flux at the surface of the treatment lysimeters followed the relationship [log(10) CO(2) (mg C m(-2) h(-1))=0.93+0.058x OBS temp. (degrees C)-0.042x12 h rain (mm)]. There was considerable variation in the rate of oil decomposition in sands collected from different sites. Sand from Askernish supported most microbial activity whilst sand from Tain was relatively inactive. The decomposition process appeared to cease when the sand became saturated with water, i.e. temporarily anaerobic. However, decomposition recommenced when the soil dried out. The fastest rate of decomposition occurred in sand from one of the two sites predicted to have high populations of hydrocarbon-degrading bacteria. Larger particle size and higher Ca content may also be significant factors governing the rate of decomposition.

Intraocular silicone prosthesis implantation in eyes of dogs and a cat with intraocular neoplasia: nine cases (1983-1994).

OBJECTIVE: To determine the outcome of implantation of an intraocular silicone prosthesis (ISP) in the eyes of dogs and cats with intraocular neoplasia. DESIGN: Retrospective case series. ANIMALS: Eight dogs and 1 cat with histologically confirmed intraocular neoplasia. PROCEDURE: Signalment, clinical signs before and after surgery, results of microscopic examination of eviscerated intraocular tissues, follow-up information, and necropsy findings, if available, were recorded for each animal. RESULTS: Five dogs and 1 cat had primary intraocular neoplasms. Two of the dogs developed regrowth of the neoplasm around the ISP 6 to 24 months after implantation, and the eyes were enucleated. The cat developed signs compatible with systemic metastasis 4 years after surgery and was euthanatized. Three dogs had multicentric or metastatic neoplasia involving the eye. Two of these dogs were euthanatized because of their systemic disease 1.5 to 7 months after ISP implantation. The third dog is alive without evidence of regrowth 3 years after surgery. CLINICAL IMPLICATION: Intraocular neoplasia is not an absolute contraindication to ISP implantation.

Use of laser flaremetry to measure aqueous humor protein concentration in dogs.

The blood-aqueous barrier in dogs is compromised by uveitis, surgery, and limbal paracentesis. Breakdown of the blood-aqueous barrier allows protein into the aqueous humor and results in mild to severe inflammation. Diagnosis of protein in the aqueous humor is traditionally a subjective measurement. Laser flaremetry was used for noninvasive quantitation of aqueous humor protein concentration in dogs. Flaremetry data were compared with aqueous humor protein concentrations obtained from aqueous humor paracentesis and slit-lamp flare evaluations. Results from clinically normal eyes and those with uveitis and cataracts were compared. Subjective evaluations of flare were correlated with a range of flaremetry readings and aqueous humor protein concentrations. Clinically normal eyes had a range of flaremetry readings of 1.4 to 7.0 photon counts (PC)/ms, with a mean of 3.8 PC/ms. Corresponding aqueous humor protein concentrations ranged from 5 to 28 mg/dl, with a mean of 15.1 mg/dl. Eyes with uveitis or cataracts had a range of aqueous protein concentrations of 13 to 729 mg/dl. Flaremetry readings accurately and sensitively measured total protein concentrations in the aqueous humor of dogs.

Efficacy of lateral canthotomy and cantholysis in orbital hemorrhage.

Emergent orbital decompression in tense orbital hemorrhage with compromised ophthalmic blood flow may be achieved with lateral canthotomy, defined as incision of the lateral canthal tendon, and cantholysis, defined as canthotomy combined with disinsertion of at least the inferior crus of the lateral canthal tendon. This study was performed to determine which procedure, canthotomy, canthal tendon disinsertion, or cantholysis, produced the largest reduction in intraocular pressure after simulated orbital hemorrhage in 10 closed ruminant orbits with retrobulbar injections of normal saline. Intraocular pressure (IOP) reductions were measured after canthotomy in five orbits, after lateral canthal tendon disinsertion in five orbits, and after completion of cantholysis in all 10 orbits. Canthotomy produced a mean IOP reduction of 14.2 mm Hg. Canthal tendon disinsertion (CTD) produced a mean IOP reduction of 19.2 mm Hg. Cantholysis produced a mean IOP reduction of 30.4 mm Hg, a significantly (p < 0.05) greater reduction in IOP than that produced by canthotomy or canthal tendon disinsertion alone. Cantholysis in acute orbital hemorrhage may produce significantly greater reduction in IOP, and thus in intraorbital pressure, and allow better perfusion of orbital tissues than either lateral canthotomy or CTD.

Lymphoplasmacytic keratitis in a ferret with lymphoma.

Unilateral lymphoplasmacytic keratitis was believed to be associated with multicentric lymphoma in a ferret. Plasmacytosis (Aleutian disease) should be considered in any ferret with lymphoplasmacytic infiltration of any organ. Ferrets with antibodies to the parvovirus causing plasmacytosis are believed to be more susceptible to concurrent disease because of immunosuppression.

A controlled trial of scheduled replacement of central venous and pulmonary-artery catheters.

BACKGROUND: The incidence of infection increases with the prolonged use of central vascular catheters, but it is unclear whether changing catheters every three days, as some recommend, will reduce the rate of infection, It is also unclear whether it is safer to change a catheter over a guide wire or insert it at a new site. METHODS: We conducted a controlled trial in adult patients in intensive care units who required central venous or pulmonary-artery catheters for more than three days. Patients were assigned randomly to undergo one of four methods of catheter exchange: replacement every three days either by insertion at a new site (group 1) or by exchange over a guide wire (group 2), or replacement when clinically indicated either by insertion at a new site (group 3) or by exchange over a guide wire (group 4). RESULTS: Of the 160 patients, 5 percent had catheter-related bloodstream infections, 16 percent had catheters that became colonized, and 9 percent had major mechanical complications. The incidence rates (per 1000 days of catheter use) of bloodstream infection were 3 in group 1, 6 in group 2, 2 in group 3, and 3 in group 4; the incidence rates of mechanical complications were 14, 4, 8, and 3, respectively. Patients randomly assigned to guide-wire-assisted exchange were more likely to have bloodstream infection after the first three days of catheterization (6 percent vs. 0, P = 0.06). Insertions at new sites were associated with more mechanical complications (5 percent vs. 1 percent, P = 0.005). CONCLUSIONS: Routine replacement of central vascular catheters every three days does not prevent infection. Exchanging catheters with the use of a guide wire increases the risk of bloodstream infection, but replacement involving insertion of catheters at new sites increases the risk of mechanical complications.