Significant Excursions Research Articles

Transequatorial Migrations by Basking Sharks in the Western Atlantic Ocean

The world's second largest fish, the basking shark (Cetorhinus maximus), is broadly distributed in boreal to warm temperate latitudes of the Atlantic and Pacific oceans from shallow coastal waters to the open ocean. Previous satellite archival tagging in the North Atlantic has shown that basking sharks move seasonally, are often associated with productive frontal zones, and may make occasional dives to mesopelagic depths. However, basking sharks are thought to be restricted to temperate latitudes, and the extent to which they exploit deeper-water habitat remains enigmatic. Via satellite archival tags and a novel geolocation technique, we demonstrate here that basking sharks are seasonal migrants to mesopelagic tropical waters. Tagged sharks moved from temperate feeding areas off the coast of southern New England to the Bahamas, the Caribbean Sea, and onward to the coast of South America and into the Southern Hemisphere. When in these areas, basking sharks descended to mesopelagic depths and in some cases remained there for weeks to months at a time. Our results demonstrate that tropical waters are not a barrier to migratory connectivity for basking shark populations and highlight the need for global conservation efforts throughout the species range.

High-resolution isotope stratigraphy of the Devonian–Carboniferous boundary in the Namur–Dinant Basin, Belgium

The Devonian–Carboniferous (D–C) boundary sequence of the Namur–Dinant Basin in southern Belgium consists of marine platform carbonates. Global biostratigraphic correlation of the boundary has been a dilemma due to the absence of index conodont zones. Despite the scarcity of brachiopods, we managed to sample twenty-five calcitic shells from boundary beds at the Royseux-Gare section, to reconstruct biochemostratigraphic profiles of oxygen-, carbon- and strontium-isotopes for correlations with established global counterparts. The δ 18O and δ 13C values of the well-preserved shells range from − 7.8 to − 6.3‰ VPDB (− 7.2 ± 0.4, n = 25) and from + 1.1 to + 2.4‰ VPDB (1.8 ± 0.3, n = 25), respectively. The shells also yielded 87Sr/ 86Sr ratios between 0.708185 and 0.708297. The Royseux isotope signatures are within the ranges documented for the global D–C boundary but their isotope profiles, however, show no significant shifts or excursions. Evaluation of the Royseux isotope profiles and correlation with their global counterparts may suggest a stratigraphic hiatus approximately from the middle Siphonodella praesulcata to the lower Siphonodella sulcata zones on the global D–C boundary conodont biostratigraphic scheme, while corresponding to the Hangenberg Event in Belgium.

Mid-Cretaceous oceanic anoxic events in the Pacific Ocean revealed by carbon-isotope stratigraphy of the Calera Limestone, California, USA

The paleoceanographic history of the Pacific Ocean during the mid-Cretaceous is poorly constrained due to the loss of much of the contemporaneous Pacific seafloor to subduction and difficulties in recovering chert-rich sediments by ocean drilling. Pelagic sediments that were originally deposited in the Pacific Ocean but that have been subsequently accreted during subduction potentially provide an alternative paleoceanographic archive. This study presents micropaleontological and carbon-isotope data from the Calera Limestone, part of the classic Franciscan Complex exposed in Permanente Quarry, central California, USA. In the three stratigraphic sections studied, pelagic limestones with low organic-carbon contents are the dominant lithology. However, two stratigraphic intervals are recognized that contain organic carbon, and these date to the early Aptian and late Albian–early Cenomanian. These time intervals correspond to two mid-Cretaceous oceanic anoxic events (OAEs): early Aptian OAE1a (equivalent to the “Selli level”) and late Albian OAE1d (equivalent to the “Breistroffer event”). It is well established that both of these events were associated with significant carbon-isotope excursions, which are also shown to exist in the Calera Limestone. The record of OAE1a from the Calera Limestone complements ocean drilling records by providing further evidence for variability in the sedimentary and stratigraphic record of this event. The carbon-isotope data from the late Albian–early Cenomanian provide the first detailed chemobiostratigraphic record of this period for the Pacific Ocean, confirming that environmental change occurred at this time in the Pacific, possibly related to OAE1d.

Fast response air-to-fuel ratio measurements using a novel device based on a wide band lambda sensor

A crucial parameter influencing the formation of pollutant gases in internal combustion engines is the air-to-fuel ratio (AFR). During transients on gasoline and diesel engines, significant AFR excursions from target values can occur, but cycle-by-cycle AFR resolution, which is helpful in understanding the origin of deviations, is difficult to achieve with existing hardware. This is because current electrochemical devices such as universal exhaust gas oxygen (UEGO) sensors have a time constant of 50–100 ms, depending on the engine running conditions. This paper describes the development of a fast reacting device based on a wide band lambda sensor which has a maximum time constant of ∼20 ms and enables cyclic AFR measurements for engine speeds of up to ∼4000 rpm. The design incorporates a controlled sensor environment which results in insensitivity to sample temperature and pressure. In order to guide the development process, a computational model was developed to predict the effect of pressure and temperature on the diffusion mechanism. Investigations regarding the sensor output and response were carried out, and sensitivities to temperature and pressure are examined. Finally, engine measurements are presented.

Optimizing Postprandial Glycemia in Pediatric Patients With Type 1 Diabetes Using Insulin Pump Therapy

OBJECTIVE—Postprandial glycemic excursions may contribute to the development of diabetes-related complications. Meals of high and low glycemic index (GI) have distinct effects on postprandial glycemia (PPG). Insulin pump therapy offers the potential to tailor insulin delivery to meal composition; however, optimal bolus types for meals of different glycemic loads have not been defined. We sought to compare the impact of GI combined with varying prandial bolus types on PPG.RESEARCH DESIGN AND METHODS—An open crossover study examining the effects of four different meal and bolus-type combinations on 3-h PPG (measured by continuous glucose-monitoring system [CGMS]) was conducted. A total of 20 young people aged 8–18 years with type 1 diabetes using insulin-pump therapy participated. Meals had equal macronutrient, energy, and fiber content and differed only in GI (low vs. high). Participants consumed meals of the same GI on consecutive days and were randomized to receive either a standard (100%) or a dual-wave (DW) (50:50% over 2 h) bolus each day. CGMS data from 10 healthy control participants established the target response to each meal.RESULTS—A DW bolus before low-GI meals decreased PPG area under the curve (AUC) by up to 47% (P = 0.004) and lowered the risk of hypoglycemia for the same premeal glucose (P = 0.005) compared with standard bolus. High-GI meals resulted in significant upward PPG excursions with greater AUC (P = 0.45), regardless of bolus type.CONCLUSIONS—These data support the use of a DW bolus with low GI meals to optimize PPG in patients with type 1 diabetes using insulin pump therapy.

Environmental change during the Late Famennian and Early Tournaisian (Late Devonian–Early Carboniferous): implications from stable isotopes and conodont biofacies in southern Europe

AbstractA biostratigraphic correlation of the Devonian/Carboniferous (D/C) boundary sections from the Carnic Alps, the Graz Palaeozoic, the Montagne Noire and the Pyrenees resulted in a high‐resolution record of the carbon isotopic composition of micrites (δ13Ccarb), of sedimentary organic matter (δ13Corg) and of oxygen isotope ratios of conodont apatite (δ18Ophosph). The studies focused on the interval between the Upper postera Zone (Late Famennian) and the sandbergi Zone (Lower Tournaisian). For the first time, weak but significant positive carbon isotope excursions in micrites and in the sedimentary organic matter is reported from the Middle and Upper expansa zones of the Carnic Alps. They coincide with a decrease in the oxygen isotope values of conodont apatite. The excursions indicate changes in the global carbon cycle during an episode of high seawater temperatures, and correlate with sedimentary change and a stepwise eustatic rise in the Rhenish Massif. High carbon isotope values were also measured in limestones from the Graz Palaeozoic in the Upper praesulcata Zone, which were previously reported from the Rhenish Massif, Carnic Alps, Montagne Noire and the North America continent. The change from a palmatolepid–polygnathid conodont biofacies to a palmatolepid–bispathodid–branmehlid biofacies in the expansa Zone in the Carnic Alps is obviously influenced by anoxic conditions and repeated transgressive phases. The protognathodids and the polygnathids start to radiate in the Upper praesulcata Zone, after the main end‐Famennian extinction episode. This is connected with the disappearance of the palmatolepids, and environmental stress created by worldwide anoxic conditions, climate change and sea‐level changes, stimulated the radiation of both protognathodids and the polygnathids. The regional correlation of the geochemical records as well as interpretations of these records on a global scale indicate that changes in conodont biofacies of Late Famennian–Early Tournaisian limestones were caused by a complex pattern of environmental changes. Copyright © 2008 John Wiley & Sons, Ltd.

Charles Burney e l’archeologia musicale dell’antica area vesuviana

During his journey through Europe (which had the aim of obtaining primary sources to be at the basis of his innovative history of music), Charles Burney went to Naples to get in contact with the culture of the city, which was very important at that time. It was 1770, and the musicologist took the opportunity – as many other distinguished travellers before him, among which we should mention Mozart – of visiting the archaeological excavations of the sites buried by the famous Vesuvius eruption of 79 AD. Of those intensive three weeks (during which he was very busy in significant meetings, excursions and reconnaisances on the enormously rich musical heritage of antiquity which had been only recently found at that time), Burney left a detailed report which became then part of the book The present state of the music in France and Italy . Many of the archaeological finds there described (basically artefacts and iconographies, in addiction to the famous Ercolano’s papyri) are nowadays still preserved, together with analogous subsequent findings, in Campanean museums and have become fundamental pieces of evidence for the knowledge of the ancient Roman music culture. In the light of modern perspectives, the rereading of Burney’s material may even today offer very interesting new ideas both to musicologists and archaeologists. Burney’s evidence on what he saw and what he had experience of results to be precious, while his method of analyses may be interpreted as the first authoritative example of modern music archaeology.

The clinical consequence of subtherapeutic anticoagulation: the low INR study (LINeRS)

Disclosure: Funding for this study was provided through the American College of Clinical Pharmacy Research Institute, the Sanofi-Aventis Thrombosis Investigator Development Award. Background Variation in warfarin anticoagulation intensity occurs frequently. Patients who spend time below their desired therapeutic range may be at increased risk for thromboembolism (TE). Previous studies report the risk of TE in relation to anticoagulation time in range over the entire study period or report a snapshot of anticoagulation status (INR level) in the setting of acute TE. However, available data fails to quantify the risk of TE for individual patients presenting with significant subtherapeutic INR excursions. The purpose of this study was to assess among patients with established, stable, therapeutic anticoagulation the proportion that experienced an anticoagulation-related adverse event (ARAE) within 90 days after a significant subtherapeutic INR excursion and calculate the hazard for an ARAE compared to a matched cohort of similar patients who did not have a subtherapeutic excursion. Methods This retrospective, longitudinal study was conducted among [15,000 patients who had been enrolled in a centralized anticoagulation service. Patients were included if they had been treated with warfarin between 1/1/1998 and 12/31/2005. Patients with at least 1 INR value C 0.5 units below their patient-specific therapeutic range (index INR), 2 previous INR results at least 2 weeks apart and within or above their therapeutic range were assigned to the Low INR cohort (LC). The LC was compared to a matched set of Therapeutic Cohort (TC) of patients treated with warfarin during the same period with a therapeutic index INR and no INR value C 0.2 units below the target range in the ensuing 90 days. Episodes of ARAE (TE, bleeding, and death) in the 90 days following the index INR were identified and validated by chart review. Proportions of the individual ARAEs were calculated and multivariate conditional Cox proportional hazards modeling was performed to estimate hazard ratios between the cohorts. Results A total of 1,596 patients in the TC were matched to 1,119 patients in the LC. Indication for anticoagulation was similar between cohorts (P [ .05): atrial fibrillation 45%, venous thromboembolism 35%, heart valve disorder 4%, and other 16%. Greater than 90% of patients in each cohort had a target INR of 2–3. Mean percent of INRs in range was higher for the LC in both the pre-period (LC 65%, TC 56%, P \ .001) and post index INR period (LC 66%, TC 51%, P \ .001). There were no differences in the proportions or adjusted hazard ratios (HR) of thromboembolism (LC 0.4%, TC 0.4%; HR = 1.7, 95% CI 0.2, 12.0), bleeding (LC 1.5%, TC 1.2%; HR = 2.2, 95% CI 0.9, 5.1), or death (LC 3.3%, TC 3.3%; HR forthcoming) between cohorts (all P [ .05). Conclusions Patients with stable, therapeutic anticoagulation experiencing and a significant subtherapeutic INR excursion at least 0.5 INR units below the patient-specific INR range have a low risk of subsequent thromboembolic events that is similar to that experienced in matched patients without such an

Catastrophic hurricane history revealed by organic geochemical proxies in coastal lake sediments: a case study of Lake Shelby, Alabama (USA)

We developed a new method for reconstructing millennia-long hurricane records from coastal environments that uses Organic Geochemical Proxies (OGPs) of organic carbon and nitrogen concentrations and their δ13C and δ15N compositions. The new method is independent of presence/absence of sand layers and improves significantly the severe-storm history resolution. The subject of this investigation is a 1.5 m long sediment core raised at 2.8 m water depth from the center of Lake Shelby, Alabama, a freshwater lake located approximately 250 m from the Gulf of Mexico, from which an overwash sand-layer based record was previously derived. The core contains two distinct sediment units; an upper 62 cm thick, fine-grained, organic-rich lacustrine sapropel (gyttja) that shows no visible structures except one sand lamina at 23.7 cm depth, and an underlying 90 cm thick, organic-poor lagoon/estuary clay unit. The sapropel unit was deposited over a 682 ± 30 cal year time interval (1320–2002 A.D.) with a mean sedimentation rate of 0.79 ± 0.04 mm/year. Lake Shelby’s water column exhibits two contrasting states based on water chemistry surveys (i) an “isolated”, stratified, mode under calm weather conditions with a relatively low trophic state, and (ii) a “flooded” mode occurring during storm surges when nutrient-rich seawater floods the lake. Statistically significant δ13C and δ15N positive excursions in organic matter, up to maximum values of −25 (‰ PDB) and 4 (‰ Air N2), respectively, are interpreted as geochemical responses to the marine intrusions that fertilize the lake, increase light availability, and cause eutrophication spikes. Detailed OGPs analyses crossing a sand layer that offers visual evidence of a catastrophic hurricane overwash event at 1717 A.D. exhibit large δ13C and δ15N positive shifts bounded by rapid returns to base values, thus confirming the validity of the hurricane identification by the OGPs model. Our data indicate that 11 catastrophic hurricanes hit the Alabama coast over the past 682 years with a rough recurrence interval of one in 62 years.

Carbon and oxygen stable isotopes across the Coniacian/Santonian boundary at Olazagutia, northern Spain

Carbon and oxygen stable isotopes have been analysed from 45 bulk sediment samples taken through a 40-m section across the Coniacian/Santonian boundary at Olazagutia, Navarra, Spain, a candidate Global Boundary Stratotype section for this stage boundary, and related to key bioevents. Carbon isotope values lie between +2.68 and +3.05‰; oxygen isotope values between −3.12 and −2.26‰, VPDB. Neither carbon nor oxygen isotope curves include significant excursions. Nevertheless, the carbon isotope curve can be correlated precisely with a published carbon isotope curve from southeast England. Within the limits of our sampling resolution (approximately one sample per 22,000 years), correlations based on carbon isotopes and on first and last occurrences of the inoceramid bivalve Platyceramus undulatoplicatus (the primary biomarker for the Coniacian/Santonian boundary) are equally accurate. Minor fluctuations in the oxygen isotope curve may reflect periodic incursions of cooler Atlantic water into the area around Olazagutia.

Correlating the Ediacaran of Australia

Abstract Now that a Global Stratotype Section and Point (GSSP) has been ratified and a new system defined for the terminal Proterozoic era, the Ediacaran, the next step is to develop global correlations and to further subdivide this system. Means of correlating and subdividing older parts of the Proterozoic era are also needed. This is not a simple task. Phanerozoic correlations depend on biostratigraphic zonation made possible by biodiversity, supported by geochronology. Proterozoic biotas are more restricted, geochronological data is often sparse, and although rapid and significant carbon isotope excursions are present through some time intervals, the curve is essentially quiescent and of limited utility at other times. Nevertheless, a foundation for Ediacaran acritarch biostratigraphy has now been established in Australia and linked to the carbon-isotope curve using sample splits. In conjunction with other correlation techniques, this has allowed the development of a continent-wide correlation scheme. The Australian Ediacaran experience suggests that an integrated approach offers the best way forward for Proterozoic subdivision. However, it raises issues about some aspects of Neoproterozoic correlation; in particular, it indicates that reliance on a two-main-glaciations model may be over simplistic.

Government, parliament and the constitution: the reinterpretation of Poynings’ Law, 1692–1714

The history of Poynings’ Law is complex and multifaceted. Much has been written about it, at times with the end result being a recognition that to investigate Poynings’ Law is to venture into a quagmire. At the same time, a number of important works have been published over the years that throw light upon specific periods in the history of that law. Until recently much of the focus has been on the period stretching from the passage of the law in 1494-5 up to 1641, with some significant excursions into the eighteenth-century history of the law.

Remarkable Features in the Interactions of Quadrupolar Molecules

Quadrupolar charge fields of molecules and of molecular fragments give rise to unique features in weakly interacting clusters and aggregations. Relative to dipole-dipole interactions, the interactions among quadrupolar molecules tend to allow for greater orientational distortions away from equilibrium. Potential surface regions have been found for several clusters that are attractive and yet very flat for certain directions. There is a notable slipperiness for the interactions in some of these cases. This implies significant vibrational excursions even in the ground state. Furthermore, the coupling of rotations among nearby molecules in pure clusters of quadrupolar molecules is different than for dipolar species, and it can lead to unexpectedly small internal rotation barriers. How these and other features develop and what they might imply for materials and biomolecular simulations are discussed here.

Anomalous Transport Due to Magnetic Turbulence

In this paper we consider transport in a toroidal system with broken flux surfaces. Flux surfaces with rational field line winding number can degenerate and form magnetic islands. Where neighbouring chains of islands overlap, a region of chaotic field forms. Thus, the generic topology of the magnetic field in a toroidal device consists of an alternation of shells with ‘good’ surfaces and shells with islands or chaotic field.In a chaotic field, a field line fills up a region of space and thus makes significant radial excursions. Particles following a chaotic field line may experience rapid radial transport. Recent experimental evidence for the existence of alternating layers with high and low thermal transport is presented. The implication for the determination of transport coefficients is discussed. It is shown that a transport analysis that does not resolve the fine structure of the transport coefficient yields results that are almost meaningless.

The Cretaceous–Palaeogene boundary succession at Stevns Klint, Denmark: Foraminifers and stable isotope stratigraphy

The Cretaceous–Palaeogene boundary exposed at Stevns Klint (Denmark) provides an important location for the investigation of the end-Cretaceous event. In this work we have used a number of sections across the boundary, including the little described, expanded stratigraphic sequence at Kulstirenden which is located 7 km north of Højerup (where most published work is derived). Using stratigraphical, micropalaeontological and stable isotope ( δ 18O and δ 13C) data we have shown that there is clear evidence of shallowing in the latest Maastrichtian. Prior to, and across, the Cretaceous–Palaeogene boundary there are significant changes in sea water temperature, including an important cooling event in the very latest Maastrichtian. The δ 13C record in the expanded boundary clay (Fish Clay) sequence at Kulstirenden indicates a number of significant excursions of decreasing magnitude up-section. The evidence from the distribution of the foraminifers has been incorporated with previous work to develop a sequence stratigraphical interpretation for the succession that can be compared to other Cretaceous–Palaeogene boundary successions in Europe.

Are there ethnic differences of facial movements between Europeans and Asians?

Due to the widespread use of Free Functional Muscle Transplant (FFMT) around the world to reanimate the paralysed face, it is important to be aware of ethnic differences in facial movements. Participants in this study were born in Taiwan (n=24) and Austria (n=24). Analyses were conducted applying the digitised three-dimensional video-analysis system. All 48 subjects have never undergone any treatments in the face nor did they have previous histories of craniofacial anomalies. In general, Europeans were observed to have larger facial movements than Asians, from 0.4 mm (e.g. 5.7%) up to 3.9 mm (e.g. 30.3%), on average 1.3 mm+/-0.82 SD (e.g. 20.6%). Particularly the eyebrow, nose and mouth regions show statistically significant larger excursions on average 1.4 mm (e.g. 19.9%), 1.3 mm (e.g. 34.6%) and 3.0 mm (e.g. 30.3%). One exception is in the eye region, where Asians have a larger excursion (1.4 mm, e.g. 15.8%) of the eyelids, due to the larger distances between the upper and lower eyelids in the rest position. Europeans have generally larger facial movements than Asians. Particularly the eyebrow, nose and mouth regions show statistically significant larger excursions; exception must be made to the eye region, where Asians have a larger excursion of the eyelids. This is the first step to gather essential information about the ethnical differences in facial movements, a factor that should be considered as FFMT is becoming more popular worldwide.

Climate factors influencing bacterial count in background air samples.

Total (as opposed to culturable) bacterial number counts are reported for four sites in the United Kingdom measured during campaigns over four separate seasons. These are interpreted in relation to simple climatic factors, i.e. temperature, wind speed and wind direction. Temperature has a marked effect at all four sites with data for a rural coastal site conforming best to a simple exponential model. Data for the other rural and urban locations show a baseline similar to that determined at the coastal rural location, but with some very significant positive excursions. The temperature dependence of bacterial number is found to conform to that typical of bacterial growth rates. At the coastal rural location, bacterial numbers normalised for temperature show no dependence on wind speed whilst at the inland sites there is a decrease with increasing wind speed of the form expected for a large area source. Only one site appeared to show a systematic relationship of bacterial concentrations to wind direction that being a site in the suburbs of Birmingham with highest number concentrations observed on a wind sector approaching from the city centre. PCR techniques have been used to identify predominant types of bacteria and results are presented which show that Bacillus was the dominant genus observed at the three inland sites during the winter and summer seasons. Pseudomonas appeared with comparable frequency at certain sites and seasons. There was in general a greater diversity of bacteria at the coastal site than at the inland sites.

Anomalous Transport due to Magnetic Turbulence

In this paper we consider transport in a toroidal system with broken flux surfaces. Flux surfaces with rational field line winding number can degenerate and form magnetic islands. Where neighbouring chains of islands overlap, a region of chaotic field forms. Thus, the generic topology of the magnetic field in a toroidal device consists of an alternation of shells with ’good’ surfaces and shells with islands or chaotic field.In a chaotic field, a field line fills up a region of space and thus makes significant radial excursions. Particles following a chaotic field line may experience rapid radial transport. Recent experimental evidence for the existence of alternating layers with high and low thermal transport is presented. The implication for the determination of transport coefficients is discussed. It is shown that a transport analysis that does not resolve the fine structure of the transport coefficient yields results that are almost meaningless.

Paleoenvironmental changes across the Cretaceous/Tertiary boundary at Flaxbourne River and Woodside Creek, eastern Marlborough, New Zealand

An integrated study of variation in siliceous microfossils, lithofacies, and other geochemical guides to environmental conditions through the Cretaceous/Tertiary (K/T) boundary transition at Flaxbourne River and Woodside Creek, coastal eastern Marlborough, indicates that the K/T impact disrupted oceanic conditions along the continental margin of eastern New Zealand for c. 1 m.y. Initial effects of the K/T event were a major reduction in carbonate production, associated with calcareous plankton extinctions, and significant increases in terrigenous clay and biogenic silica content. An absence of radiolarian extinctions or significant negative excursions in paleo‐productivity indicators (Ba, d13C) at the boundary, followed by rapid increases in the abundance of diatoms and spumellarian radiolarians, indicate that biogenic silica production partly compensated for the collapse in calcareous plankton. The earliest Paleocene recovery of calcareous plankton was short‐lived, giving way to a progressive increase in siliceous plankton abundance over c. 500 000 yr, which culminated in a c. 400 000 yr episode of peak biogenic silica production. The dominance of siliceous facies, coupled with the abundance of diatoms and spumellarian radiolarians, indicates climatic or oceanic conditions were significantly cooler than in the Late Cretaceous. Stepped increases in biogenic silica production show c. 100 000 yr periodicity, suggesting that early Paleocene lithofacies changes were influenced by climate forcing agents at the eccentricity bandwidth.

Development of hydrogen storage for fuel cell generators II: utilization of calcium hydride and lithium hydride

The feasibility of using calcium hydride or lithium hydride as a hydrogen storage system for alkaline fuel cells was investigated. Both materials can provide hydrogen at a rate required for a 1 kW unit using water vapour as the reactant. The hydrogen production reaction was found to be first order with respect to water vapour pressure over the temperature range 0–60°C. Control of the H 2 generation rate can be achieved by limiting the water vapour access to the hydride or by limiting the saturated water vapour pressure by electrolyte concentration. Some additional degree of control of the production rate is possible by using specific hydride morphologies. Modelling of the hydrogen generation was carried out using a diffusion limited rate determining step and by estimating boundary layer thicknesses and effective diffusivities. The exothermic behaviour of the hydrolysis reaction can cause significant temperature excursions within the hydride bed.