We investigated the implant-bone interface around one design of femoral stem, proximally coated with either a plasma-sprayed porous coating (plain porous) or a hydroxyapatite porous coating (porous HA), or which had been grit-blasted (Interlok). Of 165 patients implanted with a Bimetric hip hemiarthroplasty (Biomet, Bridgend, UK) specimens were retrieved from 58 at post-mortem. We estimated ingrowth and attachment of bone to the surface of the implant in 21 of these, eight plain porous, seven porous HA and six Interlok, using image analysis and light morphometric techniques. The amount of HA coating was also quantified. There was significantly more ingrowth (p = 0.012) and attachment of bone (p < 0.05) to the porous HA surface (mean bone ingrowth 29.093 +/- 2.019%; mean bone attachment 37.287 +/- 2.489%) than to the plain porous surface (mean bone ingrowth 21.762 +/- 2.068%; mean bone attachment 18.9411 +/- 1.971%). There was no significant difference in attachment between the plain porous and Interlok surfaces. Bone grew more evenly over the surface of the HA coating whereas on the porous surface, bone ingrowth and attachment occurred more on the distal and medial parts of the coated surface. No significant differences in the volume of HA were found with the passage of time. This study shows that HA coating increases the amount of ingrowth and attachment of bone and leads to a more even distribution of bone over the surface of the implant. This may have implications in reducing stress shielding and limiting osteolysis induced by wear particles.

Abstract. The "Unknown" eruption of 1808/1809 was the second most explosive SO2-rich volcanic eruption in the last two centuries, only eclipsed by the cataclysmic VEI 7 Tambora eruption in April 1815. However, no eyewitness accounts of the event, and therefore its location, or the atmospheric optical effects associated with its aerosols have been documented from historical records. Here we report on two meteorological observations dating from the end of 1808 that describe phenomena we attribute to volcanic-induced atmospheric effects caused by the Unknown eruption. The observations were made by two highly respected Latin American scientists. The first, Francisco José de Caldas, describes a stratospheric aerosol haze, a "transparent cloud that obstructs the sun's brilliance", that was visible over the city of Bogotá, Colombia, from 11 December 1808 to at least mid-February 1809. The second, made by physician José Hipólito Unanue in Lima, Peru, describes sunset after-glows (akin to well-documented examples known to be caused by stratospheric volcanic aerosols) from mid-December 1808 to February 1809. These two accounts provide direct evidence of a persistent stratospheric aerosol veil that spanned at least 2600 km into both Northern and Southern Hemispheres and establish that the source was a tropical volcano. Moreover, these observations confirm that the Unknown eruption, previously identified and tentatively assigned to February 1809 (±4 months) from analysis of ice core sulphate records, occurred in late November or early December 1808 (4 December 1808 ± 7 days). This date has important implications for the associated hemispheric climate impacts and temporal pattern of aerosol dispersal.

Abstract. The Unknown eruption of 1808/1809 was the second most explosive SO 2

In June 1787, Lieutenant Colonel Gabriel de Hervías, on behalf of the Spanish crown, took possession from Major James Lawrie of the small British settlement of Black River (Río Tinto), marking the formal end of three decades of diplomatic wrangling over the existence of the British Superintendency over the Mosquito Shore (1748 to 1787). Within three years of Lawrie's departure, along with that of 537 British settlers and 1,677 slaves, the narrow stretch of territory extending along the Atlantic coasts of Honduras and Nicaragua and known to the Spanish as costa de mosquitos was engulfed in violent conflicts between leaders of the Miskitu peoples and their followers. The first outbreak of intra-Miskitu hostilities pitted the Indian governor Colville Briton against other prominent chiefs, including his nephew Admiral Alparis Dilson; a second pitted Admiral Dilson and his brother Major Hewlett against the Afro-Indian or “Zambo” King George II. By the time the conflicts had come to an end, both Briton and Dilson had been executed, Hewlett had escaped the region for the safety of the Panamanian coast, and George had asserted his ascendancy over rival chiefs and their people.

a b s t r a c tAssessing and communicating the risks posed by natural hazards requires not only a thorough understanding of the hazards themselves but also an understanding of the spatial and temporal impact of successive events from the same source(s). This approach is enhanced by the lens of time, which is often missing from modern responses to recent hazards. Archaeological studies, in contrast, examine the longterm consequences of hazardous events, but often lack details of the event chronology and immediate human impact that are available for recent events. Here we show ways in which historical records can bridge the gap between modern and prehistoric studies. We focus on the volcanically and seismically active region that hosts the capital city of Guatemala, a city that has been relocated twice in response to hazardous events since its original founding in 1527. More specifically, we examine documents e "Autos Hechos Sobre el Lastimoso, Estrago y Ruina que Padecio esta Ciudad de Guatemala…" [Autos] e that were collected in response to a cascading sequence of volcanic, seismic and mudflow events in 1717 to support a request to the Spanish government to relocate the capital city for a second time. These documents provide exceptional detail about the location of the witnesses, the nature of the hazardous activity and the response of local communities. This detail allows us not only to reconstruct the sequence of events but also to link volcanic activity at Volc an de Fuego to local seismicity and mudflows from Volc an de Agua, which we interpret as triggered by magma intruded after the eruption of Fuego ceased. At the same time, the long and well documented history of the region allows us to examine ways in which a single catastrophic event e in this case a large rainfall-triggered debris flow from Agua in 1541, which destroyed the first capital city e can reverberate through the centuries and affect the response of the local community almost 200 years later, in 1717. The long-term effects are particularly apparent because both the origin and affected area of the mudflow hazard were very different in the two cases. This example thus illustrates the importance of "memorability" (e.g., Slovic, 2000) in both the perception of, and response to, hazardous events.