Studies in medium-ring sesquiterpenes

Imperial Users onl

A STILE Project case study: The evaluation of a computer‐based visual key for fossil identification

This paper presents an investigation of the effectiveness, for specimen identification, of a visual representation of a biological key. The example used in the investigation, the beetles database, is one of a number of resources developed under the STILE Project (Students’ and Teachers’ Integrated Learning Environment). This project uses hypermedia to provide greater opportunities for independent and flexible modes of learning both in a campus situation and for distance learning. The beetles database was constructed to aid final‐year project students’ in their identification of palaeo‐ecological field specimens. The development of this database was a response to a perceived need to reduce time spent on the time‐consuming skill of identification, and to focus students’ efforts on the significance of their field data. Four third‐year student undergraduates, two experienced and two inexperienced users of paper keys, were presented with a range of field specimens to identify using either the paper key or the STILE visual database. Our results show that the visual database was both the preferred way of operating and more effective than paper keys for all students

The Maturity of Debt Issues and Predictable Variation in Bond Returns

The maturity of new debt issues predicts excess bond returns. When the share of long-term debt issues in total debt issues is high, future excess bond returns are low. This predictive power comes in two parts. First, inflation, the real short-term rate, and the term spread predict excess bond returns. Second, these same variables explain the long-term share, and together account for much of its own ability to predict excess bond returns. The results are consistent with survey evidence that firms use debt market conditions in an effort to determine the lowest-cost maturity at which to borrow

Do firms borrow at the lowest-cost maturity? The long-term share in debt issues and predictable variation in bond returns

We document that firms tend to borrow at the lowest-cost maturity. In aggregate time series data, the share of long-term debt issues in total debt issues is negatively related to subsequent excess bond returns, meaning that firms substitute toward long-term debt when the cost of long-term debt is low relative to the cost of short-term debt. The longterm share is also contemporaneously negatively related to the components of the longterm interest rate that predict higher excess bond returns, including inflation, the real short-term rate, and the term spread. The results suggest that firms use predictable variation in excess bond returns in an effort to reduce the cost of capital

Pond biodiversity and habitat loss in the UK

Ponds are common landscape features but have been poorly studied compared to other freshwater habitats in the UK, despite their high frequency of occurrence. In the last century, many ponds have been lost and those that remain face increasing pressure due to agricultural land drainage, pollution and urban development. However, ponds provide important habitats for diverse floral and faunal communities including a number of rare taxa of conservation interest. This paper examines the biodiversity and wider environmental value of ponds with particular reference to the aquatic invertebrate and amphibian communities they support, and the adverse impact of anthropogenic activity on their aquatic habitats

The Maturity of Debt Issues and Predictable Variation in Bond Returns

The maturity of new debt issues predicts excess bond returns. When the share of long-term debt issues in total debt issues is high, future excess bond returns are low. This predictive power comes in two parts. First, inflation, the real short-term rate, and the term spread predict excess bond returns. Second, these same variables explain the long-term share, and together account for much of its own ability to predict excess bond returns. The results are consistent with survey evidence that firms use debt market conditions in an effort to determine the lowest-cost maturity at which to borrow

Do firms borrow at the lowest-cost maturity? The long-term share in debt issues and predictable variation in bond returns

We document that firms tend to borrow at the lowest-cost maturity. In aggregate time series data, the share of long-term debt issues in total debt issues is negatively related to subsequent excess bond returns, meaning that firms substitute toward long-term debt when the cost of long-term debt is low relative to the cost of short-term debt. The longterm share is also contemporaneously negatively related to the components of the longterm interest rate that predict higher excess bond returns, including inflation, the real short-term rate, and the term spread. The results suggest that firms use predictable variation in excess bond returns in an effort to reduce the cost of capital

Vascular Communications of the Hand in Patients Being Considered for Transradial Coronary Angiography Is the Allen’s Test Accurate?

ObjectivesThe purpose of this study was to assess the accuracy of the Allen’s test (AT) in predicting hand ischemia in patients undergoing transradial coronary angiography.BackgroundPatients with poor vascular communications between the radial artery (RA) and ulnar artery (UA), as indicated by an abnormal AT, are usually excluded from transradial coronary angiography to avoid ischemic hand complications.MethodsOver a four-month period, patients undergoing coronary angiography were screened for AT time. Circulation in the RA, UA, principal artery of the thumb (PAT), and thumb capillary lactate were measured before and after 30 min of RA occlusion.ResultsFifty-five patients were studied (20 normal, 15 intermediate, 20 abnormal). Three patients with an abnormal AT were excluded, owing to absence of detectible flow in the distal UA. Patients with an abnormal AT were all men, had a larger RA (3.4 vs. 2.8 mm; p <0.001), and smaller UA (1.9 vs. 2.5 mm; p <0.001), compared with patients with a normal AT. After 30 min of RA occlusion in patients with abnormal AT, blood flow to the PAT improved (3.2 to 7.7 cm/s; p <0.001) yet remained reduced relative to patients with normal AT (7.7 vs. 21.4 cm/s; p <0.001. Thumb capillary lactate was elevated in patients with an abnormal AT (2.0 vs. 1.5 mmol/l; p = 0.019).ConclusionsAfter 30 min of RA occlusion, patients with an abnormal AT showed significantly reduced blood flow to the thumb and increased thumb capillary lactate (compared with patients with a normal AT) suggestive of ischemia. Transradial cardiac catheterization should not be performed in patients with an abnormal AT

Meals for the dead:investigating Romano-British accessory vessels in burials using organic residue analysis

Accessory vessels, including platters, dishes, beakers, flagons, jars, and amphorae, are a common feature of Romano-British burials, raising questions as to their provenance; for example, were such vessels recycled from the domestic sphere or made specially for funerary purposes? Furthermore, uncertainty surrounds their purpose: did they contain foods for the deceased, possibly for their final journey to the underworld? Interestingly, organic residue analysis of vessels from Baginton, a site adjacent to The Lunt fort, Coventry, an early (mid to late first century) Roman military cremation cemetery did not yield evidence for food offerings and may have reflected the use of seconds or damaged vessels in burials, perhaps to provide a symbolic meal. In contrast, here we provide, for the first time, direct chemical and isotopic evidence for ‘meals for the dead’, comprising mainly dairy products, often mixed with leafy plants, extracted from somewhat unusual accessory vessels found in a small, enclosed inhumation cemetery, perhaps associated with a family group, which dates to the late (third to late fourth century, or early fifth century A.D) in urban Canterbury. Thus, we can confirm that accessory vessels found in later Romano-British burials were, in this instance, used in the laying out of funerary meals, presumably to nourish the soul on the journey to the underworld. These preliminary insights on vessel use and burial practices across the span of the Roman occupation of Britain thus provide a strong hint at the diversity of Roman burial practices