bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermal Shock Behavior of Two‐Dimensional Woven Fiber‐Reinforced Ceramic Composites
Authors: Wang Hongyu , Singh Raj N. , Lowden Richard A.
Published: April 2005

The thermal shock behavior of three types of two‐dimensional woven, continuous fiber‐reinforced (NextelTM 312 (3M Co., St. Paul, MN) or NicalonTM (Nippon Carbon, Tokyo, Japan)) ceramic matrix (silicon carbide matrix that had been processed by chemical vapor infiltration or polymer impregnation and pyrolysis) composites was studied using the water‐quench technique. Thermal‐shock‐induced damage was characterized by a destructive technique of four‐point flexure and a nondestructive technique of Young's modulus measurement by the dynamic resonance method. Compared with monolithic ceramics, the continuous fiber‐reinforced ceramic composites were capable of preventing catastrophic failure that was caused by thermal shock. Analysis of the results that were based on the stresses that were generated by thermal shock and the mismatch of thermal expansion between fibers and matrices suggested possible mechanisms of the thermal shock damage. Preliminary results showed evidence of matrix cracking and delamination because of the thermal shock damage. The feasibility of using the nondestructive technique to detect thermal shock damage also was demonstrated.
Crack Bifurcation in Laminar Ceramic Composites
Authors: Oechsner Matthias , Hillman Craig , Lange Fred F.
Published: April 2005

Crack bifurcation was observed in laminar ceramic composites when cracks entered thin Al2O3 layers sandwiched between thicker layers of Zr(12Ce)O2. The Al2O3 layers contained a biaxial, residual, compressive stress of ∼2 GPa developed due to differential contraction upon cooling from the processing temperature. The Zr(12Ce)O2 layers were nearly free of residual, tensile stresses because they were much thicker than the Al2O3 layers. The ceramic composites were fabricated by a green tape and codensification method. Different specimens were fabricated to examine the effect of the thickness of the Al2O3 layer on the bifurcation phenomena. Bar specimens were fractured in four‐point bending. When the propagating crack encountered the Al2O3 layer, it bifurcated as it approached the Zr(12Ce)O2/ Al2O3 interface. After the crack bifurcated, it continued to propagate close to the center line of the Al2O3 layer. Fracture of the laminate continued after the primary crack reinitiated to propagate through the next Zr(12Ce)O2 layer, where it bifurcated again as it entered the next Al2O3 layer. If the loading was stopped during bifurcation, the specimen could be unloaded prior to complete fracture. Although the residual stresses were nearly identical in all Al2O3 layers, crack bifurcation was observed only when the layer thickness was greater than ∼70 μm.
Solid‐State Diffusive Amorphization in TiO2/ZrO2 Bilayers
Authors: Shin Hyunjung , Agarwal Monika , De Guire Mark R. , Heuer Arthur H.
Published: April 2005

Thin films of crystalline TiO2 were deposited on self‐assembled organic monolayers from aqueous TiCl4 solutions at 80°C; partially crystalline ZrO2 films were deposited on top of the TiO2 layers from Zr(SO4)2 solutions at 70°C. In the absence of a ZrO2 film, the TiO2 films had the anatase structure and underwent grain coarsening on annealing at temperatures up to 800°C; in the absence of a TiO2 film, the ZrO2 films crystallized to the tetragonal polymorph at 500°C. However, the TiO2 and ZrO2 bilayers underwent solid‐state diffusive amorphization at 500°C, and ZrTiO4 crystallization could be observed only at temperatures of 550°C or higher. This result implies that metastable amorphous ZrTiO4 is energetically favorable compared to two‐phase mixtures of crystalline TiO2 and ZrO2, but that crystallization of ZrTiO4 involves a high activation barrier.
Hypophosphataemia in old patients is associated with the refeeding syndrome and reduced survival
Authors: KAGANSKY N. , LEVY S. , KOREN‐MORAG N. , BERGER D. , KNOBLER H.
Published: April 2005

Objectives.  Previous studies found that hypophosphataemia (HP) a common finding in hospitalised patients associated with unfavourable outcome, but they did not focus on old patients. The aim of the current study was to determine the prevalence, associated risk factors and potential clinical consequences of HP detected during hospitalisation in a geriatric medical centre.

Design. Case–control study.

Setting.  A total of 312‐bed geriatric division.

Subjects.  We compared 325 patients aged ≥65 years with at least one episode of HP‐group defined by serum phosphate ≤0.77 mmol L−1 with 326 patients without HP (non‐HP group).

Measurements.  Evaluation included baseline anamnesis, demographic and laboratory data. Patients in both groups were followed up to 2.7 years and clinical outcome recorded included length of hospitalisation, in‐hospital and long‐term survival.

Results.  About 14.1% of 2307 elderly had HP. Patients in the HP‐group compared with the non‐HP group had significantly more weight loss, lower albumin levels, more sepsis and received threefold more glucose‐containing infusions and twofold more food supplementations (P < 0.0001). HP was detected on average on the 10.9 ± 21.5 days of hospitalisation. Patients in the HP‐group compared with the non‐HP group, had significantly longer hospitalisation period (P < 0.0001) and reduced long‐term survival (P = 0.003) with threefold increased mortality rates. In a multivariate analysis, HP was not found to be an independent predictor of mortality.

Conclusions.  The HP was common among old hospitalised patients. Clinical characteristics of the HP‐group, the time‐course and strong association with glucose and food supplementation, are compatible with the refeeding syndrome, described previously in malnourished patients. HP was associated with significantly reduced survival.
Metabolic syndrome is associated with early signs of organ damage in nondiabetic, hypertensive patients
Authors: LEONCINI G. , RATTO E. , VIAZZI F. , VACCARO V. , PARODI D. , PARODI A. , FALQUI V. , TOMOLILLO C. , DEFERRARI G. , PONTREMOLI R.
Published: April 2005

Objectives.  Hypertensive patients with metabolic syndrome (MS) are at greater risk for cardiovascular disease. To get a better understanding of the pathophysiology underlying this association, we evaluated the relationship between MS and subclinical organ damage in essential hypertensive patients.

Design and setting.  A total of 354 untreated, nondiabetic patients with primary hypertension were included in the study. A modified ATP III definition for MS was used, with body mass index replacing waist circumference. Albuminuria was measured as albumin to creatinine ratio, left ventricular mass index (LVMI) was assessed by echocardiography and carotid abnormalities by ultrasonography.

Results.  The prevalence of MS was 25%. Patients with MS were more likely to be smokers (P = 0.004) and had higher serum uric acid levels (P = 0.004). Moreover, they showed higher urinary albumin excretion (P = 0.0004) and LVMI (P = 0.0006), increased intima‐media thickness (P = 0.045), as well as higher prevalence of microalbuminuria (P = 0.03) and left ventricular hypertrophy (LVH; P = 0.003). After adjusting for age, gender and duration of hypertension, we found that the presence of MS entails a twofold greater risk for microalbuminuria (P = 0.04), LVH (P = 0.003) and carotid abnormalities (P < 0.05). When patients were stratified according to the number of components of MS, albuminuria (P = 0.002) and LVMI (P = 0.005) increased progressively across categories.

Conclusions.  Metabolic syndrome is associated with subclinical organ damage in nondiabetic, essential hypertensive patients. These data may, in part, explain the high cardiovascular morbidity and mortality that is observed in hypertensive patients with MS.
Severity of coronary artery stenosis is associated with a polymorphism in the CXCL16/SR‐PSOX gene
Authors: LUNDBERG G. A. , KELLIN A. , SAMNEGÅRD A. , LUNDMAN P. , TORNVALL P. , DIMMELER S. , ZEIHER A. M. , HAMSTEN A. , HANSSON G. K. , ERIKSSON P.
Published: April 2005

Objective.  Enhanced expression of CXCL16 has been demonstrated in atherosclerotic plaques and several properties have been attributed to CXCL16 that could influence the atherosclerotic process. CXCL16 exists in transmembrane and soluble forms. The transmembrane form acts as a scavenger receptor for oxidised LDL whereas the soluble form acts a chemoattractant for mainly CD8+ T cells. In addition, the soluble form of CXCL16 influences human aortic smooth muscle cell proliferation in vitro. In the present work, a human molecular genetic approach employing a common polymorphism within exon 4 of CXCL16 (181 Ala>Val) was used to investigate whether CXCL16 may be involved in the development of coronary artery disease. The polymorphism is located within the spacer region between the chemokine and transmembrane region and potentially influences an Ala/Val cleavage site, a site commonly used for the release of chemokines by tumour necrosis factor‐α converting enzyme.

Design and subjects.  We first genotyped 387 unselected survivors of a first myocardial infarction aged <60 years and 387 sex‐ and age‐matched controls. A subset of patients (n = 236) was evaluated by quantitative coronary angiography. Secondly, a cohort of 468 patients undergoing percutaneous transluminal coronary angioplasty (PTCA) with stent implantation was genotyped.

Results.  No significant difference in allele frequency between patient and controls of the 181 A>V polymorphism was detected. However, the V‐allele was associated with increased severity of coronary stenoses. Secondly, the V‐allele was associated with smaller minimal luminal diameter in the coronary segment subjected to intervention in a second cohort of patients undergoing PTCA with stent implantation.

Conclusions.  The present work provides evidence that CXCL16 is involved in processes leading to enhanced stenosis in atherosclerotic coronary arteries.
Low‐dose aspirin for secondary cardiovascular prevention – cardiovascular risks after its perioperative withdrawal versus bleeding risks with its continuation – review and meta‐analysis
Authors: BURGER W. , CHEMNITIUS J.‐M. , KNEISSL G. D. , RÜCKER G.
Published: April 2005

Objectives.  Low‐dose aspirin given for secondary prevention of cardiovascular disease is frequently withdrawn prior to surgical or diagnostic procedures to reduce bleeding complications. This may expose patients to increased cardiovascular morbidity and mortality. Aim of the study was to review and quantify cardiovascular risks because of periprocedural aspirin withdrawal and bleeding risks with the continuation of aspirin.

Methods.  We screened MEDLINE (January 1970–October 2004) with additional manual cross‐referencing for clinical studies, surveys on the opinions of doctors and guidelines.

Results.  Studies reporting the relative risk of acute cardiovascular events after aspirin withdrawal when compared with its continuation were not found. However, retrospective investigations revealed that aspirin withdrawal precedes up to 10.2% of acute cardiovascular syndromes. The time interval between discontinuation and acute cerebral events was 14.3 ± 11.3 days, 8.5 ± 3.6 days for acute coronary syndromes, and 25.8 ± 18.1 days for acute peripheral arterial syndromes (P < 0.02 versus acute coronary syndromes). On aspirin‐related bleeding risks, we obtained 41 (12 observational retrospective, 19 observational prospective, 10 randomized) studies, reporting on 49 590 patients (14 981 on aspirin). Baseline frequency of bleeding complications varied between 0 (skin lesion excision, cataract surgery) and 75% (transrectal prostate biopsy). Whilst aspirin increased the rate of bleeding complications by factor 1.5 (median, interquartile range: 1.0–2.5), it did not lead to a higher level of the severity of bleeding complications (exception: intracranial surgery, and possibly transurethral prostatectomy). Surveys amongst doctors on the management of this problem demonstrate wide variations. Available guidelines are scarce and in part contradictory.

Conclusions.  Only if low‐dose aspirin may cause bleeding risks with increased mortality or sequels comparable with the observed cardiovascular risks after aspirin withdrawal, it should be discontinued prior to an intended operation or procedure. Controlled clinical studies are urgently needed.
Prognostic value of erythrocyte sedimentation rate in ST segment elevation myocardial infarction: interaction with hyperglycaemia
Authors: TIMMER J. R. , OTTERVANGER J. P. , HOORNTJE J. C. A. , DE BOER M.‐J. , SURYAPRANATA H. , VAN'T HOF A. W. J. , ZIJLSTRA F. ,   THE ZWOLLE MYOCARDIAL INFARCTION STUDY GROUP
Published: April 2005

Objectives. Many inflammatory markers are associated with an adverse prognosis after ST segment elevation myocardial infarction (STEMI). Hyperglycaemia may exacerbate this inflammatory response. We investigated whether the erythrocyte sedimentation rate (ESR) was associated with an adverse prognosis and whether this was mediated by glucose levels.

Research design and methods. It concerns apost hocanalysis of a prospective randomised trial. In 346 patients with STEMI treated with reperfusion therapy, we investigated long‐term outcome. Patients with ESR in the upper quartile (>14 mm h−1) were compared to patients with a normal ESR. Hyperglycaemia was defined as admission glucose ≥7.8 mmol L−1. Median follow up was 7.4 years (range: 5.7–8.3).

Main outcome measures. All cause mortality, cardiovascular mortality, sudden death, death as a result of heart failure.

Results. Both elevated ESR and hyperglycaemia were associated with a worse prognosis and increased mortality. Elevated ESR was particularly associated with an increased risk of sudden death (OR: 3.3, 17% vs. 6%,P < 0.01) whereas hyperglycaemia was especially associated with an increased risk of death because of heart failure (OR: 6.5, 8% vs. 1%,P < 0.01). There was no association between increased ESR and elevated glucose levels. Multivariate analysis did reveal that both elevated ESR and admission glucose were independent predictors of long‐term mortality.

Conclusions. Elevated ESR and admission glucose are independent predictors of mortality in STEMI patients treated with reperfusion therapy. There is no association or interaction between glucose levels and the inflammatory response as reflected by ESR.
Acute inflammatory sensorimotor polyradiculoneuropathy associated with immune thrombocytopenic purpura
Authors: SATO N. , KAMATA T. , AKIYAMA N. , KUWANA M. , KANDA T.
Published: April 2005

Although acute inflammatory polyneuropathy (AIP) and immune thrombocytopenic purpura (ITP) are both believed to be immune‐mediated disorders, only a few cases have been reported in which these two diseases co‐existed. We describe a case of a 67‐year‐old patient who developed quadriparesis, ophthalmoplegia and severe sensory impairment along with thrombocytopenia. Detailed examinations, including the measurement of anti‐ganglioside antibodies and anti‐glycoprotein‐IIb‐IIIa‐IgG‐producing B‐cells, revealed that he developed AIP and ITP. By reviewing past similar reports, we noticed that AIP associated with ITP tends to manifest severe sensory impairment and is often preceded by upper respiratory tract infection, but not by gastrointestinal infection.
Thermolabile methylenetetrahydrofolate reductase enzyme genotype is frequent in type 2 diabetic patients with normal fasting homocysteine levels
Authors: TUTUNCU N. B. , ERBAS T. , ALIKASIFOGLU M. , TUNCBILEK E.
Published: April 2005

Objective. To investigate the plasma homocysteine concentrations with regard to nutritional, metabolic and genetic factors and to find out the frequency and impact of thermolabile methylenetetrahydrofolate reductase (T‐MTHFR) polymorphism in patients with type 2 diabetes mellitus.

Design. A cross‐sectional study.

Subjects. A total of 94 subjects with type 2 diabetes mellitus and 91 healthy age‐ and sex‐matched nonsmoking volunteers were recruited.

Main outcome measures. Age, sex, duration and complications of diabetes mellitus, metabolic variables, fasting plasma homocysteine levels, and presence of T‐MTHFR polymorphism were evaluated for all participants. Presence of T‐MTHFR polymorphism was analysed to define any possible role in diabetes progress, complications and metabolic milieu.

Results. Fasting homocysteine levels were similar in diabetic patients and controls. Prevalence of homozygous polymorphism of thermolabile MTHFR gene (TT) was encountered more frequently in patients with diabetes mellitus than the healthy controls (P = 0.004). Subgrouping of the patients with respect to MTHFR genotype revealed similar metabolic variables and frequency of chronic complications of diabetes mellitus in groups. Patients withTTgenotype revealed longer diabetes duration when compared with the patients having heterozygous mutation of thermolabile MTHFR or normal homozygous MTHFR genotypes (P = 0.046).

Conclusions. Type 2 diabetic patients have similar fasting plasma homocysteine levels with that of age‐ and sex‐matched healthy people. There is no correlation between diabetic complications and this amino acid metabolite. On the contrary, thermolabile variant of MTHFR genotype is found to be more frequent in diabetic patients especially in those who have experienced a longer duration of disease.
Chronic fentanyl application induces adrenocortical insufficiency
Authors: OLTMANNS K. M. , FEHM H. L. , PETERS A.
Published: April 2005

We report a case of a 64‐year‐old man with secondary adrenocortical insufficiency who has been on a chronic transdermal fentanyl treatment because of sciatic pain syndrome. Shortly before admission to our hospital, the patient had discontinued his hydrocortisone medication. Adrenal crisis was assumed and during therapy with hydrocortisone infusion, the patient recovered. We suspected an opiate‐induced suppression of the hypothalamus‐pituitary‐adrenal (HPA) axis. Therefore, we gradually reduced the opiate dosage. After 1 week, HPA axis function was markedly improved. We conclude that opiate medication may inhibit – in a life‐threatening way – the organism's ability to respond to physical, emotional or metabolic stressors.
Effects of atorvastatin and vitamin E on lipoproteins and oxidative stress in dialysis patients: a randomised‐controlled trial
Authors: DIEPEVEEN S. H. A. , VERHOEVEN G. W. H. E. , VAN DER PALEN J. , DIKKESCHEI L. D. , VAN TITS L. J. , KOLSTERS G. , OFFERMAN J. J. G. , BILO H. J. G. , STALENHOEF A. F. H.
Published: April 2005

Objectives.  The objective of this study was to examine the effects of treatment with atorvastatin, α‐tocopherol and the combination of both, on lipoproteins and oxidative stress in dialysis patients.

Design and setting.  This double‐blind randomised placebo‐controlled trial was performed at the dialysis department of a non‐university hospital.

Subjects, intervention and measurements.  A total of 44 clinically stable, non‐diabetic patients on dialysis therapy (23 on haemo‐ and 21 on peritoneal‐dialysis) without manifest cardiovascular disease were included in this study. They were randomised for treatment during a period of 12 weeks with 40 mg atorvastatin + placebo α‐tocopherol (group 1) once daily, 800 IU α‐tocopherol + placebo atorvastatin once daily (group 2), 40 mg atorvastatin + 800 IU α‐tocopherol once daily (group 3), or placebo atorvastatin + placebo α‐tocopherol once daily (group 4). Assessment of lipid profile and oxidative stress was performed at the start of the study and after 12 weeks of treatment.

Results.  Treatment with atorvastatin reduced total cholesterol, triglycerides (TG), low‐density lipoprotein (LDL) cholesterol, apolipoprotein B (apoB) and levels of oxidised LDL (oxLDL) with 30–43%. It had no influence on LDL oxidisability. Additional supplementation with α‐tocopherol had no effect on lipid profile and oxLDL levels but decreased in vitro LDL oxidisability. No side‐effects were observed.

Conclusions.  Treatment with atorvastatin is effective in lowering plasma total cholesterol, TG, LDL, apoB and oxLDL in a population of stable dialysis patients and might therefore be an effective tool in improving the poor cardiovascular outcome in these patients. Supplementation of α‐tocopherol to atorvastatin had beneficial effects on in vitro LDL oxidisability and might therefore be of additional value. Further research on the clinical effects of treatment with atorvastatin in combination with α‐tocopherol is necessary.
Incident coronary events and case fatality in relation to common carotid intima‐media thickness
Authors: ROSVALL M. , JANZON L. , BERGLUND G. , ENGSTRÖM G. , HEDBLAD B.
Published: April 2005

Objectives.  To evaluate the incidence of coronary events (CE) and case fatality in relation to common carotid intima‐media thickness (IMT) and carotid plaque over a median follow up of 7 years.

Subjects.  A total of 5163 Swedish middle‐aged men and women with no prior myocardial infarction and/or stroke.

Methods and results.  The associations amongst B‐mode ultrasound determined common carotid IMT, carotid plaque (focal IMT > 1.2 mm) and carotid stenosis (lumen reduction of >15%) and incident CE, were investigated in relation to cardiovascular risk factor levels. Age‐ and sex‐adjusted common carotid IMT, carotid plaque and carotid stenosis were significantly (P < 0.05) related to future CE. Adjustment for established risk factors generally reduced the hazard rate ratios. However, the continuous measure of common carotid IMT, carotid plaque and carotid stenosis were significantly related to incident CE, even after risk factor adjustment. The strength of the associations between common carotid IMT and CE was only to a small extent reduced after adjustment for presence of carotid plaque. There were no statistically significant associations between common carotid IMT, carotid plaque or carotid stenosis and short‐term case‐fatality rates (28‐days mortality) or long‐term case‐fatality rates (5‐years mortality).

Conclusions.  The results show an association between common carotid IMT and incident CE, independently of cardiovascular risk factors and carotid plaque. However, there was no association with short‐term or long‐term mortality after a CE.
Chills in ‘early sepsis’: good for you?
Authors: VAN DISSEL J. T. , NUMAN S. C. , VAN'T WOUT J. W.
Published: April 2005

We evaluated the predictive value of chills, bacteraemia and endotoxaemia for in‐hospital mortality and survival at 5–10 years long‐term follow‐up in a prospective cohort of ‘early sepsis’ patients presenting with fever resulting from community‐acquired pneumonia or pyelonephritis. Febrile patients with chills had bacteraemia more often (RR 3.1, 95% CI 1.8–5.4) than those without chills. Neither chills nor bacteraemia were significantly related to in‐hospital mortality, but patients with endotoxaemia had a higher in‐hospital mortality rate than those without endotoxaemia. Patients with chills had a significantly higher survival rate at long‐term follow‐up than those without chills on admission: the estimated risk of dying was 0.644 (95% CI 0.43–0.95, P = 0.029) for an individual with chills, compared to a person without chills, adjusting for the other factors [age cohort, underlying disease and the pro‐inflammatory response in the blood, i.e. tumour necrosis factor‐α (TNF‐α) and blood leucocyte number, as scored on hospital admission] in the Cox proportional hazards model. Chills may characterize a patient subpopulation that upon pulmonary and urinary tract infection is able to raise a more rapid and/or efficient host response.
Failure of current public educational campaigns to impact on the initial response of patients with possible heart attack
Authors: Bett J. H. N. , Tonkin A. M. , Thompson P. L. , Aroney C. N.
Published: April 2005

Abstract

Aims:  The National Heart Foundation of Australia recognizes that the risk of lethal arrhythmias is greater very early after the onset of myocardial infarction and that the more promptly flow can be restored in the infarct‐related artery the greater will be the benefits for survival and preservation of heart function. The Heart Foundation has therefore conducted several public media campaigns to encourage patients to seek help more promptly and evaluated their impact.

Methods:  Since 1996, we have conducted four surveys of delays preceding admission of patients to coronary care units throughout Australia to assess the impact of the Heart Foundation's media campaigns. Data were collected on 1665 patients who presented to 73 hospitals; information on patient delay was available for 1178 of them.

Results:  There were no significant differences in patient delay (median 1.5–2.0 h) in the four surveys from 1996 to 2002, nor when patients were categorized by age, sex, presenting diagnosis or history of previous myocardial infarction or coronary revascularization by percutaneous or surgical techniques.

Conclusion:  New approaches are needed to reduce patient‐related delay after the onset of symptoms suggesting possible myocardial infarction. (Intern Med J 2005; 35: 279–282)
Economic Costs and Benefits of Combating Terrorism in the Transport Sector
Authors: Palac‐McMiken Evanor
Published: April 2005

Countering the risks of terrorism imposes enormous costs. While it is impossible to remove completely the risk of terrorist attacks in the transport sector, measures designed to counter terrorism can add certainty and stability to the global economy, raise investor confidence and facilitate trade. Modelling suggests productivity losses associated with the increasing threat of terrorism can be more than offset by the positive effects of enhanced security. Nations have much to gain from cooperating to reduce the risk of terrorism.
Joined‐up Thomism and the ‘Second Quest’ for Trinitarian Renewal
Authors: McCosker Philip
Published: April 2005

Book reviewed:

Scripture and Metaphysics: Aquinas and the Renewal of Trinitarian Theology, Matthew Levering, Blackwell 2004 (Hb 1‐4051‐1733‐8; Pb 1‐4051‐1734‐6), pp. x + 254, Hb £55/$61.95, Pb £19.99/$32.95
Outcome at 7 years of children diagnosed with autism at age 2: predictive validity of assessments conducted at 2 and 3 years of age and pattern of symptom change over time
Authors: Charman Tony , Taylor Emma , Drew Auriol , Cockerill Helen , Brown Jo‐Anne , Baird Gillian
Published: April 2005

Objective:  To examine the predictive validity of symptom severity, cognitive and language measures taken at ages 2 and 3 years to outcome at age 7 in a sample of children diagnosed with autism at age 2.

Method:  Twenty‐six children diagnosed with autism at age 2 were re‐assessed at ages 3 and 7 years. At each age symptom severity, cognitive and language assessments were completed.

Results:  The pattern of autistic symptom severity varied over time by domain. Across time, children moved across diagnostic boundaries both in terms of clinical diagnosis and in terms of instrument diagnosis on the Autism Diagnostic Interview‐Revised (ADI‐R). On all measures group variability in scores increased with age. Although non‐verbal IQ (NVIQ) for the group as a whole was stable across the 3 assessments, this masked considerable individual instability. Standard assessments at age 2 did not predict outcome at age 7 even within the same domain of functioning. In contrast, standard assessments at age 3 did predict outcome. However, a measure of rate of non‐verbal communicative acts taken from an interactive play‐based assessment at age 2 was significantly associated with language, communication and social outcomes at age 7.

Conclusions:  The trajectory of autism symptoms over time differed in different domains, suggesting that they may be, at least in part, separable. Variability in language, NVIQ and symptom severity increased over time. Caution is required when interpreting the findings from assessments of children with autism at age 2 years. At this age measures of rate of non‐verbal communication might be more informative than scores on standard psychometric tests. Predictive validity of assessments at age 3 years was greater.
Extinction in Subdivided Habitats
Authors: QUINN JAMES F. , HASTINGS ALAN
Published: April 2005

Abstract: The effect of the spatial structure of populations on extinction rates is a central question in conservation biology, ecology, and evolution. We show that the effect of subdivision on the mean time to extinction in independently varying habitat patches depends upon the relationship between extinction probabilities and habitat area Models of extinction by demographic stochasticity alone predict that subdivision should decrease the mean time to extinction. If environmental stochasticity is incorporated into the model, subdivision may increase the mean time to extinction. Empirical species persistence times estimated from island bio‐geography studies show no systematic relationship to the degree of subdivision. However, subdivision always increases the probability of survival over a sufficiently short time interval. These results suggest that over ecologically relevant timescales, subdivision into a number of independent sub‐populations may frequently act to decrease the probability of overall extinction in rare species. To the degree that these considerations may be applied to rare and endangered species, maintaining sufficient numbers of nature reserves is likely to be crucial to effective conservation strategies.
How Markets in Wildlife Meat and Parts, and the Sale of Hunting Privileges, Jeopardize Wildlife Conservation
Authors: GEIST VALERIUS
Published: April 2005

The reintroduction of markets in wildlife meat and parts jeopardizes North America's system of wildlife conservation. This most successful of conservation systems is based on three fundamental policies: denial of economic value to dead wildlife, allocation of surplus wildlife by law, and nonfrivolous use of wildlife. These policies are being undermined by game ranching, market hunting, paid hunting and advertising of hunting as sport or competition, not harvest. Agriculture in Canada advocates raising wildlife for slaughter; in the United States it supports paid hunting. The policy of removing economic value from dead wildlife paid off in a $60 billion service and manufacturing industry based on living wildlife. Some understanding of the historical roots of American wildlife management is vital to nature conservation. Making all citizens de facto as well as de fure shareholders in wildlife deserves broad attention.
The Constancy of Leopold's Land Ethic
Authors: NORTON BRYAN G.
Published: April 2005

Aldo Leopold's approach to environmental management changed drastically between the early 1920s, when he advocated predator eradication, and 1944, when he drafted “Thinking Like a Mountain.” How are we to understand these changes?

It is shown that, early in his career, Leopold developed the basic elements of a conservation ethic, borrowing key elements from the Russian organicist P. D. Ouspensky and from A. T. Hadley, an American pragmatist who was president of Yale University when Leopold was a student there. Hadley's pragmatism counseled that we act on the wisdom embodied in the intuitive perceptions of our forefathers. While Leopold changed the presentation of his conservation ethic over the years, he never gave up these key ideas, traces of which remain in the final version of “The Land Ethic.”

The changes in Leopold's management strategies were not due to a change in metaphysical or moral views, but to his evolving experience as a forester and game manager. Leopold learned that “violent” strategies, such as monocultural planting of trees, pervasive agricultural management of fragile ecosystems and, above all predator eradication, led to unforeseen and unwelcome results. Leopold recognized that we may never have adequate information to manipulate natural systems for maximal human utility without diminishing their vitality. He therefore lost faith in “economic biology” as a guide to environmental management.

Leopold's changing views on management resulted from his experience as an environmental manager, not from a conversion from utilitarian anthropocentrism to biocentric nonanthropocentrism. While Leopold was drawn to Ouspensky's organicism, and he hoped Americans would through a profound change in their perceptions of nature adopt such a view eventually, he believed throughout his career that longsighted anthropocentrism provides an adequate basis for conservation practices.
The Ecology of Extinctions in Kelp Forest Communities
Authors: ESTES JAMES A. , DUGGINS DAVID O. , RATHBUN GALEN B.
Published: April 2005

We recognize three levels of extinction–global, local, and ecological – and provide examples of each. The protection and recovery of sea otters (Enhydra lutris) has provided abundant evidence of the consequences of their local extinction from kelp forest communities in the North Pacifc Ocean. These consequences include release of benthic invertebrate populations from limitation by predation; deforestation of kelp beds due to increased grazing by herbivorous sea urchins, one of the otter's main prey; and various cascading effects resulting from the biological and physical importance of kelp in coastal ecosystems. These interactions probably were important agents of selection for certain species.

Two other examples are discussed: Steller's sea cow (Hydrodamalis gigas), a case of global extinction, and spiny lobsters, a possible case of ecological extinction. We speculate that grazing by sea cows was an important disturbance to surface‐canopy‐forming kelps and other algae in the littoral zones, but also point out that any such interactions probably acted in concert with physical disturbances by ocean waves. The ecological and evolutionary importance of sea cow grazing probably will remain a matter of speculation and conjecture because the species is globally extinct.

Predation by spiny lobsters limits a variety of littoral and sublittoral invertebrate populations, particularly mollusks In one remarkable example, the reduction or local extinction of spiny lobsters enabled predutory whelks to increase in size and abundance, ultimately resulting in a predutor‐prey role reversal. From these and other case studies we can clued that (1) the extinction of consumers may have brad and sometimes unexpected influences on kelp forest ecosystems; (2) direct or indirect interactions with now‐extinct species probably exerted important selective influences on many extant forms; (3) such ecological and evolutionary influences are best understood where local or ecological extinctions, followed by recoveries, have provided comparisons in space or time; and (4) because of various ecological and behavioral barriers, local extinctions and their ecological consequences may not be simply reversed by protecting or reintroducing depleted or locally extinct species.
Invasion and Extinction: The Last Three Million Years of North Sea Pelecypod History
Authors: VERMEIJ GEERAT J.
Published: April 2005

Biotic interchange occurs when two or more biotas with separate evolutionay histories come together as barriers between them become less effective. The idea that extinction of species often accompanies invasion of species during biotic interchange is rooted in the view that the success of invasion is controlled largely by competition or predation among newcomers and native species. An analysis of the stratigraphical ranges of pelecypod species from the Pliocene and Pleistocene of the North Sea Basin revealed that the magnitude of extinction is not cowelated with the absolute number of species invading from the North Pacific following the opening of the Bering Strait during the Middle Pliocene or from the Mediterranean during the Early Pleistocene, and that North Pacific invaders and native North Sea species were equally susceptible to extinction during the Early Pleistocene. I suggest that, although invasion may result in populational and ecological shifts in the recipient biota, it should rarely bring about extinction among marine species because marine competitors and predators are almost never 100 percent successful in locating and killing their victims, and because marine populations tend to be large. The fact that many invaders from the North Pacifc and Mediterranean first became established in the North Sea during the Pleistocene points to the possibility that the reoccupation of the North Sea by marine organisms following periods of emergence provided unusually good opportunities for the successful invasion of foreign species.
Cyclic Drought, Dispersal, and the Conservation of the Snail Kite in Florida: Lessons in Critical Habitat
Authors: TAKEKAWA JEAN E. , BEISSINGER STEVEN R.
Published: April 2005

Studies of the dispersal of the Florida Snail Kite, an endangered hawk that inhabits flooded wetlands and feeds almost solely on apple snails, illustrate the problems associated with protecting habitats for migratoty and wandering species with disjunct habitat requirements. Before a drought in 1985, most kites 2oere sighted in the large tracts of Everglades that were used for nesting. During the drought however, 60 percent of the sightings of kites reported to our sighting hotline were from smaller wetlands and other drought‐related habitats, mostly in Palm B e d and surrounding counties Although these small wetlands are important emergency habitats used by kites to suruive during drought, they are not designated as “critical habitat” and are being developed at a rapid rate We discuss the problems of uncertainty, cumulative effects, and compromise in theprocess of evaluating development proposals and protecting small; isolated habitats. We identify key sites used by kites during drought and suggest ways to conserve this species in Florida by mitigating drought‐induced population crashes The usefulness of sighting hotlines for assessing dispersal data is also evaluated.
Rethinking Crop Genetic Resource Conservation
Authors: BRUSH STEPHEN B.
Published: April 2005

Abstract: A worldwide system of crop germplasm conservation has been developed around ex situ preservation This system is based on a dual mandate of conservation and development; and it has largely ignored the farming systems that produce germplasm A revisionist critique of the existing system is presented Problems of the current strategy include incomplete collection loss within these collections, isolation from evolutionary processes, and budgetary constraints. In situ conservation offers an alternative to current methods, especially if conservation rather than development is the priority. The concept of genetic erosion is discussed and evaluated in light of recent evidence of uneven change in areas of crop diversity. Farmers in many parts of the world are conserving traditional varieties even as they modernize and adopt improved varieties. This pattern is illustrated by reference to Asian rice agriculture. A new approach to conservation is needed that builds a collaborative program between farmers, crop scientists, ecologists, biogeographers, and social scientists. A first step is to analyze farming systems that already conserve traditional crop varieties.
The Population Dynamics and Conservation of Primate Populations
Authors: DOBSON ANDREW P. , LEES ANNA MARIE
Published: April 2005

Abstract: Primates are among the most threatened taxa, with more than half of all species in jeopardy. In this paper we develop population models to use the kind of data on wild primates that primatologists actually collect. Our survey of recentprimate journals suggests that the average field study uses 1.5 years of data from 50 animals The models are based on the simple Leslie‐Lefkovitch matrix. They suggest a simple method that allows assessment from a few years’data, of whether a population is collapsing and requires intervention To a good approximation, populations will collapse when adult survival, per inter‐birth interval, is less than 70 percent.

Modifications of the basic model incorporate more realistic assumptions about social organization and densitydependent resource limitation. These allow us to identify population densities at which potential Allee effects operate, and permit more precise estimates of the minimum population sizes and compositions required for successful reintroductions to the wild The most important result is that populations of primates that live in small family groups may be more prone to “demographic” extinction than are more promiscuous species that live in more extended groups.
Reestablishment of the Perdido Key Beach Mouse (Peromyscus polionotus trissyllepsis) on Gulf Islands National Seashore
Authors: HOLIER N. R. , MASON D. W. , DAWSON R. M. , SIMONS T. , WOOTEN M.C.
Published: April 2005

Abstract: In April 1986, the endangered Perdido Key beach mouse (Peromyscus polionotus trissyllepsis) existed only as a small population of less than 30 animals on the western end of Perdido Key at Gulf State Park, Alabama This population was vulnerable to extinction from a variety of causes. Fifteen pairs of mice from Alabama were moved approximately 20 km on the same island to Gulf Islands National Seashore Florida between November 1986 and April 1988. The Alabama population was surveyed by live‐trapping before each removal and showed a large increase during this study. Eleven pairs of mice were released into enclosures to stimulate burrowing and reduce dispersal at the release site. The last four pairs w e released unrestricted into the dune habitat Trapping in July 1988 revealed that virtually all available dune habitat (11,000 linear m; approximately 160 ha) had been occupied by the mice. Fifty‐five individuals were captured including four of the released mice. Exchanges between the populations are recommended to prevent loss of genetic diversity. Future research should investigate demographics, dispersal pattern, and the application of DNA fingerprinting techniques to determine rates of gene flow in the population. The Perdido Key beach mouse provides an excellent model for studying the effects of a population bottleneck on genetic diversity and testing the predictions of population viability analysis.
Viable Populations, Reserve Size, and Federal Lands Management: A Critique
Authors: GRUMBINE R. EDWARD
Published: April 2005

An examination of current viable population theories and reserve size studies suggests that biological diversity for North American national parks and forests is inadequately protected This conclusion is further supported by reviews of federal agency management plans and policies. Preservation of biodiversity is thwarted by lack of landscape–level management, insufficient data, competition between federal land management agencies, and bureaucratic inertia, among other factors. To dress these problems, an ecosystem management model for reform is outlined New legislation is also suggested. Ethical and social choices are recognized as the basis for any restructuring of land management to protect biodiversity.
Founding Lineages and Genic Variability in Plains Bison (Bison bison) from Badlands National Park, South Dakota
Authors: MCCLENAGHAN LEROY R. , BERGER JOEL , TRUESDALE HAROLD D.
Published: April 2005

Abstract: Starch‐gel electrophoresis was used to screen 101 bison from Badlands National Park, South Dakota, for variation at 24 genetic loci. The population was descended from founder groups of about 6 and 3 individuals, separated geographically for a minimum of 64 years. The purpose of this study was (1) to estimate levels of genic variability in this bison population, (2) to assess the extent to which descendents of the two founder groups differ genetically, and (3) to compare the genetic characteristics of the Badlands population with other bison populations. The Badlands herd was found to be polymorphic for only a single locus (MDH–1). Descendents of the founder groups were homogeneous with respect to allelic and genotypic frequencies at this locus. The MDH–1 polymorphism has not been observed in other bison populations, while several polymorphism reported in other bison populations were not detected in the Badlands herd. A mean heterozygosity of 0.012 was observed in the Badlands herd; this value is lower than that typically reported for mammals, though not as low as heterozygosities seen in other populations that have passed through severe bottlenecks in size. These results underscore the need for genetic data in planning breeding programs for species in captivity or managed in isolate reserves.
Conservation of the Yellowstone Grizzly Bear
Authors: MATTSON DAVID J. , REID MATTHEW M.
Published: April 2005

Abstract: We review literature relevant to the conservation of Yellowstone's grizzly hear population and appraise the bear's long‐term viability. We conclude that the population is isolated and vulnerable to epidemic perturbation and that the carrying capacity of the habitat is likely to shift downward under conditions of climate change. Viability analyses based on the assumption that future habitats will closely resemble those existing at present have limited applicability; more information is needed on the autecology of important bear foods and on the implications of landscape‐scale changes for bear population dynamics. Optimism over prospects of long‐term persistence for Yellowstone's grizzly bears does not seem to be warranted and management of this population should be conservative and not unduly swayed on short‐term positive trends.
Influence of Fragmentation and Bottlenecks on Genetic Divergence of Wild Turkey Populations
Authors: LEBERG PAUL L.
Published: April 2005

Abstract: There are few empirical studies of the effects of human‐induced fragmentation and bottlenecks on the genetic structure of field populations. Assessment of these effects is necessary to evaluate the relevance of predictions obtained from simulation and theoretical models to the management of wild populations. The genetic structure of populations of the Wild Turkey (Meleagris gallopavo), which have been heavily influenced by human activities, was examined using allozyme electrophoresis Allele frequencies at four polymorphic loci were estimated for 27 localities using 461 turkeys The estimated proportion of genetic variation resulting from differences among populations (Fst= 0.102) was one of the highest reported for any avian species and was also much higher than that observed between turkey populations that had not passed through known bottlenecks Almost all of the variation (89%) among populations was accounted for by differences between groups of populations with different histories of manipulation Fragmented distributions and population bottlenecks due to human activities appear to have increased genetic differentiation among populations of wild turkeys. This observation agrees with theoretical predictions concerning the effects of isolation and bottlenecks on the genetic structure of field populations.