bluuebunny/crossref_metadata_2025 huggingface dataset:
Six years of in situ CO2 enrichment evoke changes in soil structure and soil biota of nutrient‐poor grassland
Authors: NIKLAUS P. A. , ALPHEI J. , EBERSBERGER D. , KAMPICHLER C. , KANDELER E. , TSCHERKO D.
Published: December 2004

Nutrient‐poor grassland on a silty clay loam overlying calcareous debris was exposed to elevated CO2 for six growing seasons. The CO2 exchange and productivity were persistently increased throughout the experiment, suggesting increases in soil C inputs. At the same time, elevated CO2 lead to increased soil moisture due to reduced evapotransporation. Measurements related to soil microflora did not indicate increased soil C fluxes under elevated CO2. Microbial biomass, soil basal respiration, and the metabolic quotient for CO2 (qCO2) were not altered significantly. PLFA analysis indicated no significant shift in the ratio of fungi to bacteria. 0.5 m KCl extractable organic C and N, indicators of changed DOC and DON concentrations, also remained unaltered. Microbial grazer populations (protozoa, bacterivorous and fungivorous nematodes, acari and collembola) and root feeding nematodes were not affected by elevated CO2. However, total nematode numbers averaged slightly lower under elevated CO2 (−16%, ns) and nematode mass was significantly reduced (−43%, P = 0.06). This reduction reflected a reduction in large‐diameter nematodes classified as omnivorous and predacious. Elevated CO2 resulted in a shift towards smaller aggregate sizes at both micro‐ and macro‐aggregate scales; this was caused by higher soil moisture under elevated CO2. Reduced aggregate sizes result in reduced pore neck diameters. Locomotion of large‐diameter nematodes depends on the presence of large enough pores; the reduction in aggregate sizes under elevated CO2 may therefore account for the decrease in large nematodes. These animals are relatively high up the soil food web; this decline could therefore trigger top‐down effects on the soil food web. The CO2 enrichment also affected the nitrogen cycle. The N stocks in living plants and surface litter increased at elevated CO2, but N in soil organic matter and microbes remained unaltered. Nitrogen mineralization increased markedly, but microbial N did not differ between CO2 treatments, indicating that net N immobilization rates were unaltered. In summary, this study did not provide evidence that soils and soil microbial communities are affected by increased soil C inputs under elevated CO2. On the contrary, available data (13C tracer data, minirhizotron observations, root ingrowth cores) suggests that soil C inputs did not increase substantially. However, we provide first evidence that elevated CO2 can reduce soil aggregation at the scale from µm to mm scale, and that this can affect soil microfaunal populations.
Three years of free‐air CO2 enrichment (POPFACE) only slightly affect profiles of light and leaf characteristics in closed canopies of Populus
Authors: GIELEN B. , LIBERLOO M. , BOGAERT J. , CALFAPIETRA C. , DE ANGALIS P. , MIGLIETTA F. , SCARASCIA‐MUGNOZZA G. , CEULEMANS R.
Published: December 2004

Modelling is used to predict long‐term forest responses to increased atmospheric CO2 concentrations. Although productivity models are based on light intercepted by the canopy, very little experimental data are available for closed forest stands. Nevertheless, the relationships between light inside a canopy, leaf area, canopy structure, and individual leaf characteristics may be affected by elevated CO2, affecting in turn carbon gain.

Using a free‐air CO2 enrichment (FACE) design in a high‐density plantation of Populus spp., we studied the effects of increased CO2 concentrations on transmittance (τ) of photosynthetic photon flux density (Qp), on ratios of red/far‐red light (R/FR), on leaf area index (LAI), on leaf inclination, on leaf chlorophyll (chl) and nitrogen (N) concentrations, and on specific leaf area (SLA) in the 2nd and 3rd years of treatment. Continuous measurements of τ were made in addition to canopy height profiles of light and leaf characteristics.

Two years of Qp measurements showed an average decrease of canopy transmittance in the FACE treatment, with very small differences at canopy closure. Results were explained by an unaffected LAI in closed canopies, without a FACE‐induced stimulation of relative crown depth. In agreement, leaf inclination and extinction coefficients for light were similar in control and FACE conditions. Ratios of R/FR were not significantly affected by the FACE treatment, neither were leaf characteristics, with the exception of leaf N, which allows speculation about N limitation. In general, treatment differences in canopy profiles resulted from an initial stimulation of height growth in the FACE treatment. P. × euramericana differed from P. alba and P. nigra, but species did not differ significantly in their response to the FACE treatment. By the time fast‐growing high‐density forest plantations have passed the exponential growth phase and reached canopy closure, the likely effects of elevated atmospheric CO2 concentration on canopy architecture and absorption of Qp are minor.
Elevated CO2 and temperature alter nitrogen allocation in Douglas‐fir
Authors: TINGEY DAVID T. , MCKANE ROBERT B. , OLSZYK DAVID M. , JOHNSON MARK G. , RYGIEWICZ PAUL T. , HENRY LEE E.
Published: December 2004

The effects of elevated CO2 and temperature on principal carbon constituents (PCC) and C and N allocation between needle, woody (stem and branches) and root tissue of Pseudotsuga menziesii Mirb. Franco seedlings were determined. The seedlings were grown in sun‐lit controlled‐environment chambers that contained a native soil. Chambers were controlled to reproduce ambient or ambient +180 ppm CO2 and either ambient temperature or ambient +3.5 °C for 4 years. There were no significant CO2 × temperature interactions; consequently the data are presented for the CO2 and temperature effects. At the final harvest, elevated CO2 decreased the nonpolar fraction of the PCC and increased the polar fraction and amount of sugars in the needles. In contrast, elevated temperature increased the nonpolar fraction of the PCC and decreased sugars in needles. There were no CO2 or temperature effects on the PCC fractions in the woody tissue or root tissue. Elevated CO2 and temperature had no significant effects on the C content of any of the plant tissues or fractions. In contrast, the foliar N content declined under elevated CO2 and increased under elevated temperature; there were no significant effects in other tissues. The changes in the foliar N concentrations were in the cellulose and lignin fractions, the fractions, which contain protein, and are the consequences of changes in N allocation under the treatments. These results indicate reallocation of N among plant organs to optimize C assimilation, which is mediated via changes in the selectivity of Rubisco and carbohydrate modulation of gene expression.
Super‐optimal temperatures are detrimental to peanut (Arachis hypogaea L.) reproductive processes and yield at both ambient and elevated carbon dioxide
Authors: Vara Prasad P. V. , Boote Kenneth J. , Hartwell Allen L. , Thomas Jean M. G.
Published: December 2004

Continuing increases in atmospheric carbon dioxide concentration (CO2) will likely be accompanied by global warming. Our research objectives were (a) to determine the effects of season‐long exposure to daytime maximum/nighttime minimum temperatures of 32/22, 36/26, 40/30 and 44/34°C at ambient (350 μmol mol−1) and elevated (700 μmol mol−1) CO2 on reproductive processes and yield of peanut, and (b) to evaluate whether the higher photosynthetic rates and vegetative growth at elevated CO2 will negate the detrimental effects of high temperature on reproductive processes and yield. Doubling of CO2 increased leaf photosynthesis and seed yield by 27% and 30%, respectively, averaged across all temperatures. There were no effects of elevated CO2 on pollen viability, seed‐set, seed number per pod, seed size, harvest index or shelling percentage. At ambient CO2, seed yield decreased progressively by 14%, 59% and 90% as temperature increased from 32/22 to 36/26, 40/30 and 44/34°C, respectively. Similar percentage decreases in seed yield occurred at temperatures above 32/22°C at elevated CO2 despite greater photosynthesis and vegetative growth. Decreased seed yields at high temperature were a result of lower seed‐set due to poor pollen viability, and smaller seed size due to decreased seed growth rates and decreased shelling percentages. Seed harvest index decreased from 0.41 to 0.05 as temperature increased from 32/22 to 44/34°C under both ambient and elevated CO2. We conclude that there are no beneficial interactions between elevated CO2 and temperature, and that seed yield of peanut will decrease under future warmer climates, particularly in regions where present temperatures are near or above optimum.
The impact of defoliation frequency and nitrogen fertilizer application in spring on summer survival of perennial ryegrass under grazing in subtropical Australia
Authors: Donaghy D. J. , Fulkerson W. J.
Published: December 2004

Abstract This field study investigated the effect of timing of nitrogen (N) fertilizer application in spring on the survival of grazed perennial ryegrass (Lolium perenne cv. Dobson and Yatsyn) over summer in a subtropical environment. There were five N fertilizer treatments: no applied N, 46 kg N ha−1 on 22 October or 22 November or 22 December, or on 22 October and again on 22 December. Water‐soluble carbohydrate (WSC) concentration of perennial ryegrass plants entering the summer was altered by varying defoliation frequency, with defoliation interval based on the number of leaves per tiller. Frequent defoliation was set at a regrowth level of one leaf per tiller and less frequent defoliation at a regrowth level of three leaves per tiller, over a total of two by three‐leaf per tiller regrowth periods. Application of N fertilizer was found to have no significant effect (P > 0·05) on survival of perennial ryegrass plants over summer. On the other hand, defoliation had a marked effect on perennial ryegrass persistence, with frequent defoliation decreasing ryegrass plant density (51 vs. 88 plants m−2; P < 0·001) and increasing the density of tropical weed grasses (99 vs. 73 plants m−2; P < 0·001) by autumn. Frequently defoliated plants had a lower stubble WSC content on a per plant basis than less frequently defoliated plants in spring (103 vs. 201 mg per plant; P < 0·001) and summer (59 vs. 101 mg per plant; P < 0·001). The lower WSC content was associated with a smaller root system in spring (1·50 vs. 2·14 g per plant; P < 0·001) and autumn (1·79 vs. 2·66 g per plant; P < 0·01), and this was reflected in 0·29 more plants being pulled from the soil by livestock between November 1996 and April 1997. Rhizoctonia fungus was associated with roots of pulled plants, but not with roots of seemingly healthy plants, indicating that this fungus may have a role in a weakened root system, which was more prone to sod pulling. Nitrogen applied in October and November resulted in a reduced WSC concentration, although the effect was restricted to 1 month after N application. The present study indicates that survival of perennial ryegrass plants over the summer in a subtropical region is prejudiced by frequent defoliation, which is associated with a lower WSC concentration and a shallower root system. Under grazing, sod pulling is a reflection of this weaker root system and contributes to plant mortality.
Effects of a stay‐green trait on the concentrations and stability of fatty acids in perennial ryegrass
Authors: Dewhurst R. J. , Moorby J. M. , Scollan N. D. , Tweed J. K. S. , Humphreys M. O.
Published: December 2004

Abstract Three experiments were conducted to evaluate the effect of a stay‐green trait in perennial ryegrass (Lolium perenne) on concentrations of fatty acids as well as their susceptibility to peroxidation during wilting and to biohydrogenation by rumen bacteria. Fatty acid concentrations were recorded in stay‐green and corresponding normal perennial ryegrass selection lines over eight cuts during 1998. There was a progressive increase in total fatty acid concentrations [from 20·8 to 34·6 g kg−1 dry matter (DM)] and the proportion of fatty acids as α‐linolenic acid (from 0·62 to 0·70 g g−1) from early to late season. A second study compared fatty acid concentrations in stay‐green and normal herbage that was wilted for up to 48 h. There was a loss of 0·2–0·3 g g−1 fatty acids during 48 h of wilting and a small reduction in the rate of loss of α‐linolenic acid in stay‐green perennial ryegrass compared with normal herbage (0·223 vs. 0·290 g g−1 lost after 48 h). Stay‐green and normal perennial ryegrasses were offered to grazing lambs in a third study. Higher concentrations of trans‐vaccenic acid and conjugated linoleic acid in plasma from lambs offered less mature grass in the pre‐experimental period than during the experiment are considered to reflect a greater supply of precursor (linoleic acid). There were higher concentrations of conjugated linoleic (0·0070 vs. 0·0039 g l−1) and linoleic (0·092 vs. 0·070 g l−1) acids, without an increase in trans‐vaccenic acid, in plasma from lambs grazing stay‐green perennial ryegrass than normal perennial ryegrass. This suggests that the stay‐green trait affected the rate of degradation of fatty acids in the rumen. These results demonstrate the potential for obtaining proportionately large differences in fatty acid profiles of ruminant products by altering grassland management.
Emotional reactions of haemophilia health care providers
Authors: BROWN LARRY K. , STERMOCK ANNE C. , FORD HARRIET H. , GEARY MARGARET
Published: December 2004

This study investigated the prevalence and impact of job burnout and job satisfaction among health care professionals working with HIV‐infected patients with haemophilia, using a survey that included the Maslach Burnout Inventory (MBI). A minority (7.4%) of the 213 respondents met the criteria for job burnout as assessed by the MBI. Nearly 90% of the respondents reported `liking' their job, although only 46% anticipated being in the same job in 5 years. The following factors were associated with increased degrees of burnout: greater perceived colleague stress, less overall job satisfaction, greater perceived stress in the working environment, fewer team meetings and fewer years of career experience. Mental health professionals were also less likely than physicians to report burnout. A multiple logistic regression found that providers who reported stress with colleagues were 42% more likely than their peers to be classified as experiencing a high level of job burnout. This study underscores the importance of a well‐functioning team in buffering the inevitable stresses of caring for haemophilia patients with HIV.
Acquired inhibitor against factor IX in a child: successful treatment with high‐dose immunoglobulin and dexamethasone
Authors: MAZZUCCONI M. G. , PERAINO M. , BIZZONI L. , BERNASCONI S. , LUCIANI M. , ROSSI G. DE
Published: December 2004

The occurrence of acquired inhibitor against factor IX:C is infrequent in haemophilia B patients and is very rare in previously healthy subjects, in whom it is often related to underlying diseases.

We describe the case of a 2‐year‐old girl, who was referred to our hospital with haematomas, without previous bleeding history. Prolonged APTT, normal PT and a factor IX:C level below 1% were found. An inhibitor against factor IX:C was detected (5.5 U mL−1). Her father and mother showed normal factor IX:C levels. Treatment with high‐dose immunoglobulin (400 mg kg−1 day−1 for 5 consecutive days by intravenous infusion) and dexamethasone (4 mg three times a day by intravenous injection for 4 consecutive days) normalized factor IX:C levels and overcame the inhibitor.

In conclusion, high‐dose immunoglobulin and high‐dose dexamethasone are a successful and safe immunosuppressive approach for recovery from inhibitor occurrence.
The treatment of flexion contracture of the knee using the Ilizarov technique in a child with haemophilia B
Authors: Kiely P. D. , McMahon C. , Smith O. P. , Moore D. P.
Published: December 2004

Summary.  Severe factor IX deficiency is an X‐linked disorder which gives rise to spontaneous and often life‐threatening bleeds. The major source of morbidity worldwide is recurrent haemarthroses, giving rise to joint destruction and deformity. However, the incidence of spontaneous haemarthroses has decreased since the advent of prophylactic home‐based, on‐demand, early replacement therapy.

We present the case of a non‐ambulant, 13‐year‐old boy from Chernobyl, who did not have access to this type of treatment, and whose deformity was managed using the Ilizarov external fixator.

An external fixator was applied under general anaesthetic in theatre. Haemostasis was achieved by maintaining his FIX levels at 1.0 IU mL−1 pre‐ and post‐operatively. Three months later, the fixed flexion deformity had been reduced from 50 to 5°. Four months postsurgery, this boy was walking freely without pain. There was no peri‐ or post‐operative bleeding or joint swelling.
Immune tolerance therapy dose as an outcome predictor
Authors: DiMichele Donna
Published: December 2004

Summary.  The question of dose as a successful ITT outcome predictor in haemophilia A and B is an important one on many levels. Increased morbidity associated with inhibitor development has been documented [3]. Currently, immune tolerance is the only proven method for inhibitor eradication. Furthermore, given the morbidity and the high cost of less effective bypass therapy, a study by Harvard health economists using Markov decision analysis predicted an increased life expectancy of 4.5 years at a lifetime cost savings of $1.6 million with the use of ITT rather than lifelong APCC therapy [25].

However, the immediate short‐term cost of this expensive therapeutic intervention has the capacity to strain the financial resources of many countries in the developed world, regardless of the system of medical reimbursement. It also assures the inaccessibility of this treatment modality to most of the world's inhibitor patients living in the developing world. Cost aside, recent experience has taught us that clotting factor supply is precarious, not inexhaustible as previously assumed. Finally, in the paediatric patient who is most likely to require and undergo ITT, venous access for daily infusions is problematic with or without a central venous access device. Indeed, for these reasons alone, finding the answer to the question of optimal cost‐effective dosing immune tolerance is a matter of medical urgency and moral obligation to the global haemophilia community.
Comparative effectiveness of full‐length and B‐domain deleted factor VIII for prophylaxis – a meta‐analysis
Authors: Gruppo R. A. , Brown D. , Wilkes M. M. , Navickis R. J.
Published: December 2004

Summary.  Recently reported data suggest the possibility of differences in clinical efficacy between full‐length factor VIII (FL‐FVIII) and B‐domain deleted recombinant factor VIII (BDD‐rFVIII). To address this question, we conducted a meta‐analysis of studies reporting the incidence of bleeding under prophylaxis, as well as studies of FL‐FVIII and BDD‐rFVIII half‐life. The pooled cumulative weekly prophylactic dose of BDD‐rFVIII (81.3 ± 13.8 IU kg−1 week−1) was greater by 36% (P = 0.11) than that of FL‐FVIII (60.0 ± 5.9 IU kg−1 week−1). The pooled incidence of bleeding in BDD‐rFVIII recipients [16.8 bleeds per patient year; confidence interval (CI), 9.5–24.2 bleeds per patient year] was more than 2.5‐fold larger (P < 0.0005) than that in patients receiving FL‐FVIII (6.6 bleeds per patient year; CI, 4.7−8.5 bleeds per patient year). In a multivariate analysis, the incidence rate ratio was 2.10 (CI, 1.98−2.24), indicating that breakthrough bleeding under prophylaxis was more than twice as likely with BDD‐rFVIII than FL‐FVIII at equivalent doses and ages. The pooled half‐life for plasma‐derived FL‐FVIII (13.7 h; CI, 12.8−14.6 h) was closely similar to that for recombinant FL‐FVIII (14.3 h; CI, 13.3−15.4 h). By contrast, the pooled half‐life for BDD‐rFVIII (11.3 h; CI, 9.9−12.7 h) was shorter by approximately 3 h compared with FL‐FVIII. Although the results of the meta‐analysis need to be interpreted with caution, the pooled data suggest that breakthrough bleeding under prophylaxis may occur more frequently in patients receiving BDD‐rFVIII than FL‐FVIII and may at least partly reflect a more abbreviated half‐life of BDD‐rFVIII. Several biochemical differences between BDD‐rFVIII and FL‐FVIII may underlie the observed disparities in bleeding incidence and half‐life. This meta‐analysis should be confirmed by further studies.
Management of haemophilia B inhibitor patients with anaphylactic reactions to FIX concentrates
Authors: Shibata M. , Shima M. , Misu H. , Okimoto Y. , Giddings J. C. , Yoshioka A.
Published: December 2004

Summary.   Allergic reactions to concentrates containing factor IX (FIX) are serious complications in the treatment of haemophilia B patients with inhibitor. We have established a therapeutic protocol for such cases using an initial skin test followed by step‐wise infusions of FIX concentrates under hydrocortisone cover. We have successfully treated three patients whose treatment with FIX had been suspended.
Immune tolerance induction in patients with haemophilia A with inhibitors: a systematic review
Authors: Wight J. , Paisley S. , Knight C.
Published: December 2004

Summary.  In some patients with haemophilia A, therapeutically administered factor VIII (FVIII) comes to stimulate the production of antibodies (inhibitors) which react with FVIII to render it ineffective. As a result, FVIII cannot be used prophylactically and patients become liable to recurrent bleeds. There are two elements to the management of patients with inhibitors: the treatment of bleeding episodes, and attempts to abolish inhibitor production through the induction of immune tolerance.

This paper reports a systematic review of the best available evidence of clinical effectiveness in relation to immune tolerance induction (ITI) in patients with haemophilia A with inhibitors. Owing to the lack of randomized controlled trials on this topic, broad inclusion criteria with regard to study design were applied in order to assess the best available evidence for each intervention. As a result of the clinical and methodological heterogeneity of the evidence, it was not appropriate to pool data across studies; instead, data were synthesized using tabulation and qualitative narrative assessment.

The International Registry provides the most reliable estimate of the proportion of successful cases of ITI [48.7%, 95% confidence interval (CI) 42.6–52.7%]. The duration of effect is unclear, but relapses appear to be infrequent. The International Registry shows a rate of relapse of 15% at 15 years. The comparative effectiveness of different protocols is uncertain, as no trials have been undertaken which compare them directly. However, the evidence suggests that the Bonn protocol may be more effective than the Malmö or low‐dose protocols. There is no good evidence that immunosuppressive drug regimens are effective.
Home management of haemophilia
Authors: Teitel J. M. , Barnard D. , Israels S. , Lillicrap D. , Poon M.‐C. , Sek J.
Published: December 2004

Summary. The demonstrated benefits of home care for haemophilia include improved quality of life, less pain and disability, fewer hospitalizations, and less time lost from work or school. Although reduced mortality has not been demonstrated, the substantial increase in longevity since the early 1980s correlates with the introduction of home treatment and prophylaxis programmes. These programmes must be designed and monitored by haemophilia treatment centres (HTC), which are staffed with professionals with broad and complementary expertise in the disease and its complications. In return, patients and their families must be willing to accept the reciprocal responsibilities that come from administering blood products or their recombinant equivalents at home. Patients with inhibitors to factors VIII or IX pose special challenges, but these complications do not obviate participation in home care programmes. Home care was an essential prerequisite to the introduction of effective prophylactic factor replacement therapy. Prophylaxis offers significant improvements in quality of life, but requires a substantial commitment. The use of implantable venous access devices can eliminate some of the difficulty and discomfort of peripheral venous access in small children, but brings additional risks. The future holds the promise of factor concentrates for home use that have longer half‐lives, or can be administered by alternate routes. Knowledge of patient genotypes may allow treatments tailored to avoid complications such as inhibitor development. Gene therapy trials, which are currently ongoing, will ultimately lead to gene‐based treatments as a complement to traditional protein‐based therapy.
Health‐related quality of life as outcome parameter in haemophilia treatment
Authors: Fischer K. , Van Der Bom J. G. , Van Den Berg H. M.
Published: December 2004

Summary.  Health‐related quality of life (HRQoL) is increasingly used as an outcome parameter in haemophilia treatment. Currently, only generic HRQoL instruments are used, as disease‐specific instruments for haemophilia are not available. The most widely used generic instruments are the descriptive SF‐36 questionnaire and the EQ‐5D questionnaire for assessment of utilities, ie preference‐based HRQoL. Results of both instruments show significant correlation. All haemophilia prophylaxis studies using HRQoL as an outcome report a decreased HRQoL compared with the general population, a positive effect of prophylactic treatment and a negative effect of age. Generic instruments for measuring HRQoL are able to pick up differences between groups of patients with haemophilia and enable us to make comparisons across diseases. However, in order to establish the optimal treatment strategy for severe haemophilia, further information is needed on the long‐term effects of different strategies on HRQoL. In addition, haemophilia‐specific HRQoL instruments should be developed in order to provide detailed information for adjustment and evaluation of treatment in individual patients.
Economics of prophylactic treatment
Authors: Schramm W. , Berger K.
Published: December 2004

Summary.  Clinical studies have shown significant improvement in outcomes with the use of prophylactic treatment, as well as apparent gains in health‐related quality of life. Given the high cost and still limited availability of factor concentrates, physicians, insurers and governments require cost‐effectiveness data to evaluate competing treatments (eg prophylactic vs. on‐demand treatment) and to set priorities within the context of each country's financial resources. To date, the few published studies of the cost‐effectiveness of haemophilia prophylaxis have generally focused on the reduction in frequency of bleedings as an intermediate outcome, and not on long‐term health outcomes, such as the development of arthropathy and its social and economic costs. Since all prophylactic measures are investments for the future, long‐term economic consequences need to be carefully studied and evaluated.
How to start prophylaxis
Authors: Petrini P.
Published: December 2004

Summary.  A cohort study was performed to assess the efficacy of a gradual introduction to primary prophylaxis by peripheral vein injections. Bleeding symptoms prior to the initiation of prophylaxis and during the time from the start of home treatment were investigated. Forty‐seven boys with severe haemophilia, born between 1987 and 2000, were studied. The mean age at the start of prophylaxis was 16 months and the mean age for the boys on home treatment and full prophylaxis was 30 months. Our results show that primary prophylaxis with injections in a peripheral vein is possible in most patients (83%). Even with this early start, 59% of the children had been treated with clotting factor concentrate before prophylaxis was initiated. Seventy‐two percent of the boys had no symptoms from the joints or muscles in the time from initiation to full prophylaxis every second (haemophilia A) or third day (haemophilia B). None of the patients developed cerebral bleeding during this period, but one patient had an epidural bleeding as the presenting symptom of haemophilia.
A global view on prophylaxis: possibilities and consequences
Authors: Shapiro A. D.
Published: December 2004

Summary.  Prophylactic infusion therapy, both primary and secondary, has proven of great benefit to patients with haemophilia, specifically those with severe disease or bleeding episodes and patterns that have lead to development of arthropathy. At this time, optimal outcome in patients with severe haemophilia has been proven achievable with primary prophylaxis initiated at an early age in a regimen of three times weekly or every other day for patients with factor VIII deficiency, and twice weekly for those with factor IX deficiency. Despite the demonstrated benefit of primary prophylaxis, this treatment regimen has not been uniformly adopted into clinical practice even in developed countries. In developing countries, where issues of allocation of precious health care resources are of paramount importance, access to adequate treatment for persons with haemophilia on a programme of on‐demand therapy is not commonly available; the cost of primary prophylaxis, even with intermediate purity plasma‐derived factor concentrates or plasma fractions such as cryoprecipitate, renders this treatment the exception rather than the rule.
Redesigning mental health services: lessons on user involvement from the Mental Health Collaborative
Authors: Robert Glenn , Hardacre Jeanne , Locock Louise , Bate Paul , Glasby Jon
Published: December 2004

Objectives  To explore the involvement of mental health service users in the redesign of in‐patient mental health services in six Trusts participating in a multi‐regional NHS modernization programme.

Design  Semi‐structured interviews and observation of team meetings undertaken as part of an action research study.

Participants and setting  Users, clinical, medical and managerial staff from six mental health trusts which participated in the Northern & Yorkshire and Trent regions’ Mental Health Collaborative (MHC).

Results and conclusions  Whilst there were some problems, user involvement was undoubtedly a strength of the MHC in comparison to other modernization programmes within the NHS we have studied. However, the particular challenges posed by the specific context of acute mental health services should not be overlooked. The initial approach taken in each of the sites was to simply invite a user or user representative to join the local project team. In the course of events, various changes were made to this initial mechanism for involving users in the ongoing work of the teams. These changes – and setbacks in some sites – make drawing firm conclusions as to the effectiveness of the various strategies employed problematic. However, our qualitative data suggest a number of broad lessons that will assist both those leading and participating in other redesign initiatives to maximize the benefits to be gained from service user involvement.
A statistical approach to strength evaluation incorporating porosity effect for porous ceramics
Authors: HOSHIDE T. , ABE J.
Published: December 2004

ABSTRACT It has not been clear whether the conventional effective volume proposed for dense brittle materials can be applied satisfactorily to the strength evaluation of porous ceramics. In the present study, a modified effective volume was proposed by incorporating the porosity effect in the statistical evaluation of strength properties of porous ceramics. The modified effective volume was derived as the conventional effective volume multiplied by a function of porosity p. In this work, a power function of (1 + p)a was adopted as the simplest porosity function. To clarify the applicability of the modified effective volume, bending tests were conducted using smooth and notched specimens of 3 wt% MgO partially stabilised zirconia with six different porosities. The porosity dependence appeared in the relation between the conventional effective volume and the mean strength of various zirconia ceramics with different porosities. The exponent a of the porosity function was determined from experimental data obtained by using identically shaped specimens with distinct porosities, and the modified effective volume was calculated for several types of specimens used in the experiments. It was revealed that the mean strength was almost uniquely correlated with the modified effective volume independent of porosity. The experimental correlation verified the applicability of the modified effective volume to strength evaluation of porous ceramics.
The effects of loading waveform and microstructure on the fatigue response of titanium aero‐engine compressor disk alloys
Authors: SHANIAVSKI A. A. , LOSEV A. I.
Published: December 2004

Microstructural variations produced from manufacturing processes and their influence on fatigue crack growth in titanium disks were investigated. Charpy‐tests on titanium disk material were performed and materials with fracture energy values in the range of 3.8–19.1 J/cm2 were selected for tests under cyclic loads. Results of Charpy‐tests were compared with fractographic features related to fatigue crack growth in Ti−6Al−3Mo−0.4Si and Ti−6Al−3Mo−2Cr alloys with a two‐phase (α + β) lamellar structure under various cyclic waveforms using specimens made from compressor disks. The material sensitivity to cyclic load waveform can be seen for in‐service disks using a criteria based on fracture energy values determined in Charpy‐tests.

A difference in fatigue crack growth periods of 2.5 times was discovered for specimens made from the disk with a filament type microstructure and the mainly globular two‐phase structure of the Ti−6Al−3Mo−0.4Si alloy. The shorter crack growth period correlated with the mainly facetted pattern formation with local zones of fatigue striations when fatigue crack growth is along the planes of the filaments. Fatigue striations are the major fracture surface relief when crack growth occurs in the perpendicular direction to the plane of the filaments. A quantitative fractographic method for estimating the crack growth period for in‐service failed disks was performed for the case of crack development along planes of such microstructural filaments created during the manufacturing process.

Specimen tests involving a hold‐time in the cyclic loads are recommended for in‐service accepted titanium disks using a criteria based on the fracture energy value. Selection of disks based on these criteria can indicate a material sensitivity to cyclic load waveforms.
Influence of anisotropy on a limit load of weld strength overmatched middle cracked tension specimens
Authors: ALEXANDROV S. , GRACIO J.
Published: December 2004

ABSTRACT A plane‐strain upper bound limit load solution for weld strength overmatched middle cracked tension specimens (M(T) specimens), is found. It is assumed that the weld material is isotropic, but the base material is orthotropic and its axes of orthotropy are straight and parallel to the axes of symmetry of the specimen. A quadratic orthotropic yield criterion is adopted. The solution is based on a simple discontinuous kinematically admissible velocity field and is an extension of the corresponding solution for the specimen made of isotropic materials. These two solutions are compared to demonstrate the influence of anisotropy on the magnitude of the limit load.
Colonization front of the understorey palmAstrocaryum sciophilumin a pristine rain forest of French Guiana
Authors: Charles‐dominique Pierre , Chave Jerome , Dubois MARC.‐A. , De Granville Jean‐Jacques , Riera Bernard , Vezzoli Cecile
Published: December 2004

AimsAstrocaryum sciophilum(Miq.) Pulle (Arecaceae) is an understorey palm, endemic to north‐eastern South America with a patchy distribution. We tested the hypothesis that the spatial distribution of this palm species is not in equilibrium but is slowly colonizing the forest understorey.

LocationInventories and seed dispersal studies were conducted in the undisturbed tropical forest close to the Nouragues research station, French Guiana. Additional data were collected in the entire territory of French Guiana.

MethodsWe studied the demography ofA. sciophilumon a 20‐ha plot located at the edge of its distribution. The age of the palms was estimated by postulating an exponentially decreasing abundance by age class. Direct seed dispersal experiments were also conducted, to estimate dispersal parameters. The seeds ofA. sciophilumwere dispersed only by rodents. This information was used to parameterize a forest growth simulator, to study the spatial spread of this species.

ResultsWithin the sampling plot, the density ofA. sciophilumdropped sharply from about 500 individuals per hectare to zero. The maturation age was estimated to be 170 ± 70 years, and over 55 years with 95% confidence. Seed‐dispersal experiments yielded an average seed dispersal distance of 11 m and a maximum estimated dispersal distance of 125 m across a generational span of 55 years to maturity. Therefore, the maximal estimated colonization speed is 2.3 m/y.

ConclusionsEmpirical results and numerical simulations suggest that the boundary of theA. sciophilumpopulation is a colonization front, and that the range of this species is slowly expanding. The implications of this result in respect of palaeoenvironmental changes in this region are discussed.
Climate‐driven changes in shoot density and shoot biomass in Leymus chinensis (Poaceae) on the North‐east China Transect (NECT)
Authors: Renzhong Wang , Qiong Gao
Published: December 2004

Aim Climate‐driven changes affecting ecosystem primary production have been well documented for many vegetation types, while the effects of climate on plant populations remains unclear. Herein, we address the relationships between climatic variables and shoot density, reproductive allocation and shoot biomass in Leymus chinensis on a large‐scale climatic gradient in 2000.

Location Nine sites experiencing similar light regimes, but differing in longitude, precipitation and altitude were selected on the North‐east China Transect (NECT) from 115° to 124°E, around a latitude of 43.5°N.

Methods Densities of total, vegetative and reproductive shoots and of shoot biomass were measured twice over the growing season in each site. Climatic data were taken from the climate database of the Laboratory of Quantitative Vegetation Ecology, Institute of Botany, Chinese Academy of Sciences and from the local weather stations throughout the NECT.

Results Densities of total, vegetative and reproductive shoots increased significantly from the west to the east and from dry to moist along the NECT, and were strongly correlated with annual precipitation (r2 = 0.934, 0.943 and 0.863, respectively) and an aridity index (r2 = 0.809, 0.816 and 0.744, respectively). The average total shoot density at the east end (470/m2) was about three times that at the west (160/m2). Reproductive allocation and shoot biomass for both vegetative and reproductive shoots increased with precipitation and declined with the aridity index along the NECT. There were positive correlations between shoot biomass and annual precipitation for vegetative shoots (P < 0.05, R2 = 0.604) and March precipitation for reproductive shoots (P < 0.05, R2 = 0.533), respectively.

Main conclusions These findings suggest that L. chinensis adjusts to decreasing precipitation/increasing aridity by alterations in shoot density, reproductive allocation and shoot biomass along the drought gradient of the NECT.
A retrospective analysis of land cover change using a polygon shape index
Authors: Comber A. J. , Birnie R. V. , Hodgson M.
Published: December 2004

Aim This study tests the hypothesis that the propensity of land cover patches to change is related to their shape and geometric complexity.

Location The analysis is based on a 1000‐km2 area of the Cairngorms in Scotland, incorporating part of Speyside and the high plateau area within the Grampian Mountains.

Methods A combined dataset was created by intersecting 1964 land cover data (derived from archive aerial photography) and 1988 land cover data (from the Land Cover of Scotland dataset). A shape index was calculated for each land cover polygon inside a GIS. Information on land cover change was analysed with reference to land cover class and the polygon shape index using a regression analysis.

Results For upland seminatural land cover classes, subject to low levels of management, change is related to polygon shape, such that the more complex patches were found to be more susceptible to change. This relationship breaks down where classes are more intensively managed or have been aggregated into mosaic classes.

Conclusions Propensity to change was related to shape index for seminatural land cover classes. This implies that at least some landscape processes, such as anthropogenic disturbance of seminatural land covers, can be linked to ecological theory via measurements of spatial pattern. The study also highlighted some of the cartographic issues involved in estimating changes between land cover classes: there are advantages in replacing the ‘cartographic paradigm’ of comparing two derived datasets (in this case land cover maps) with direct comparison of the digital data — air photographs or satellite imagery. Such a direct approach avoids the compounding of errors introduced by the approximation of each successive air photo as a thematic map.
Near extinction of a highly fecund fish: the one that nearly got away
Authors: Sadovy Yvonne , Cheung Wai Lung
Published: December 2004

It is widely assumed that commercial fisheries of highly fecund species are particularly resilient to exploitation, and that, should populations become seriously diminished, economic constraints will force fishing to cease before biological extinction can occur. Indeed, among commercially exploited marine fishes there is not one confirmed global extinction. Here we document, using nonconventional means, a story that not only questions such assumptions but that should also alert us to how little we know about significant fisheries in some parts of the world. Our case study is that of the highly threatened Chinese bahaba, Bahaba taipingensis, a member of the Sciaenidae (the drums or croakers), and an example of a fecund and commercially important group of fishes that appears to be especially vulnerable to fishing. We also demonstrate that the careful use of informal, or traditional, information can provide a powerful, sometimes unique, means of identifying and assessing the status and history of species that might be quietly slipping away before we learn anything about them.
Extinction vulnerability in marine populations
Authors: Dulvy Nicholas K , Sadovy Yvonne , Reynolds John D
Published: December 2004

Human impacts on the world's oceans have been substantial, leading to concerns about the extinction of marine taxa. We have compiled 133 local, regional and global extinctions of marine populations. There is typically a 53‐year lag between the last sighting of an organism and the reported date of the extinction at whatever scale this has occurred. Most disappearances (80%) were detected using indirect historical comparative methods, which suggests that marine extinctions may have been underestimated because of low‐detection power. Exploitation caused most marine losses at various scales (55%), followed closely by habitat loss (37%), while the remainder were linked to invasive species, climate change, pollution and disease. Several perceptions concerning the vulnerability of marine organisms appear to be too general and insufficiently conservative. Marine species cannot be considered less vulnerable on the basis of biological attributes such as high fecundity or large‐scale dispersal characteristics. For commercially exploited species, it is often argued that economic extinction of exploited populations will occur before biological extinction, but this is not the case for non‐target species caught in multispecies fisheries or species with high commercial value, especially if this value increases as species become rare. The perceived high potential for recovery, high variability and low extinction vulnerability of fish populations have been invoked to avoid listing commercial species of fishes under international threat criteria. However, we need to learn more about recovery, which may be hampered by negative population growth at small population sizes (Allee effect or depensation) or ecosystem shifts, as well as about spatial dynamics and connectivity of subpopulations before we can truly understand the nature of responses to severe depletions. The evidence suggests that fish populations do not fluctuate more than those of mammals, birds and butterflies, and that fishes may exhibit vulnerability similar to mammals, birds and butterflies. There is an urgent need for improved methods of detecting marine extinctions at various spatial scales, and for predicting the vulnerability of species.
Transient fluid flow in and around a fault
Authors: Braun J. , M. Munroe S. , Cox S. F.
Published: December 2004

We present the results of simple numerical experiments in which we study the evolution with time of fluid flow around and within a permeable fault embedded in a less permeable porous medium. Fluid movement is driven by an imposed vertical pressure gradient. The results show that fluid flow is controlled by two timescales: τf = Sl2/κF and τF = Sl2/κM, where S is the specific storage of the porous material, l the length of the fault, and κM and κF are the hydraulic conductivities of the porous material and the fault, respectively. Fluid flow and the associated fluid pressure field evolve through three temporal stages: an early phase [t < τf] during which the initial fluid pressure gradient within the fault is relaxed; a second transient stage [τf < t < τF] when fluid is rapidly expelled at one end of the fault and extracted from the surrounding rocks at the other end leading to a reduction in the pressure gradient in the intact rock; a third phase [t < τF] characterized by a steady‐state flow. From the numerical experiments we derive an expression for the steady‐state maximum fluid velocity in the fault and the values of the two timescales, τf and τF. A comparison indicates excellent agreement of our results with existing asymptotic solutions. For km‐scale faults, the model results suggest that steady‐state is unlikely to be reached over geological timescales. Thus, the current use of parameters such as the focusing ratio defined under the assumption of steady‐state conditions should be reconsidered.