Mean Survivorship Research Articles

Results of trabecular metal augments in Paprosky IIIA and IIIB defects

The advent of trabecular metal (TM) augments has revolutionized the management of severe bone defects during acetabular reconstruction. The purpose of this study was to evaluate patients undergoing revision total hip arthroplasty (THA) with the use of TM augments for reconstruction of Paprosky IIIA and IIIB defects. A retrospective study was conducted at four centres between August 2008 and January 2015. Patients treated with TM augments and TM shell for a Paprosky grade IIIA or IIIB defect, in the absence of pelvic discontinuity, and who underwent revision hip arthroplasty with the use of TM augments were included in the study. A total of 41 patients with minimum follow-up of two years were included and evaluated using intention-to-treat analysis. There were 36 (87.8%) patients with a Paprosky IIIA defect and five (12.2%) patients with a Paprosky IIIB defect. The mean age was 56.7 years (28 to 94). There were 21 (51.2%) women and 20 (48.8%) men. The mean follow-up was 39.4 months (12 to 96). One (2%) patient died after eight years. No failures were noted in the series. The mean survivorship was 100% at the time of latest follow-up. The results of this multicentre study showed encouraging short- and mid-term results for the use of TM augments in the management of Paprosky grade IIIA and IIIB defects. Cite this article: Bone Joint J 2018;100-B:903-8.

Hip replacement in patients younger than 65 years: Results of the CLS prosthesis:

We present the results of a retrospective review of 65 CLS uncemented total hip replacements in 47 patients all of whom were less than 65 years of age at the time of surgery. The mean follow-up was 6.5 years and only one case was lost to follow-up. The clinical results were good. The mean (95% confidence interval) Merle d'Aubigne Postel score for pain (max. 6) was 5.42 ± 1.13 (5.13 – 5.71) and for mobility (max. 6) 5.55 ± 0.71 (5.37 – 5.73). The mean score for patient satisfaction (max. 5) was 4.89 ± 0.46 (4.77 – 5.00). The mean total score was therefore 15.97 ± 1.70 (95% confidence interval 15.54 - 16.40) from a maximum of 17 points. There were three revisions over the study period giving a mean (95% confidence interval) survivorship of 96.5% (91.9% - 100%) at five years. We present the results of a radiological review, which show that the surviving implants show evidence of osseointegration. This was achieved despite the lack of a porous or hydroxyapatite coating.

A multi‐ingredient athletic supplement disproportionately enhances hind leg musculature, jumping performance, and spontaneous locomotion in crickets (Acheta domesticus)

AbstractNutrition is a key component of life‐history theory with profound impacts on fitness traits. We examined lifetime impacts of a multi‐ingredient athletic supplement (MAS) on physical performance, anatomical morphology, survivorship, and general life‐history features in the house cricket, Acheta domesticus (L.) (Orthoptera: Gryllidae). The MAS was formulated using 13 nutraceutical supplements that are commonly used by human athletes specifically to improve athletic performance. Cricket doses were based on human doses adjusted for body size and metabolic rate. Markers of athletic performance included: jumping distance, spontaneous locomotor activity, and morphology of the hind legs (femurs). Supplemented adult crickets jumped ca. 25% further and expressed elevated spontaneous locomotion relative to controls. The MAS disproportionately increased hind leg femur length and width. Life‐history endpoints included survivorship, juvenile growth rate, maturation age, and mature body size. Supplemented crickets showed faster juvenile growth and earlier maturation, but no change in final adult size. A 20% increase in mean survivorship (extending into older ages) was also documented. Crickets represent an excellent new model for assessing athletic diets and associated performance criteria. Finally, as experimental animals were untrained, we argue that our supplement may represent a novel ‘exercise mimetic’ that impacts both performance and survivorship.

Abstract B18: Exploring the lived experience of young African American breast cancer survivorship: Early results toward informing a psychoeducational intervention

Abstract Background/Purpose Recent data indicate that 11% of the 230,000 women diagnosed with breast cancer each year are young (18-44). Though the five-year survival rates of these young women are improving, there are large health disparities in breast cancer survivorship among young African American women in the United States (e.g. higher breast cancer incidence and mortality when compared with young Caucasians). Further, young African American breast cancer survivors (YAABCS) report poorer quality of life than young Caucasians. Despite recommendations to provide evidence-based and tailored survivorship care for cancer survivors, there are about 23,000 YAABCS between the ages of 20-49 living in a southern tri-state area (Alabama- AL, Louisiana- LA, and Mississippi- MS) for whom a comprehensive breast cancer survivorship education/support intervention does not exist. As few studies have examined YAABCS's survivorship experiences and/or tested intervention efficacy among this group, further study of their survivorship is warranted to inform the adaptation of an age- and culturally-specific survivorship psychoeducational intervention for YAABCS. As part of an ongoing dissertation study, a Research Tested Intervention Program called the Breast Cancer Education Intervention (BCEi) is being adapted into Y-AMBIENT (the BCEi for YAABCS). The purpose of this abstract is to describe early results of the lived experience of young African American breast cancer survivorship, which will be used to inform the adaptation of Y-AMBIENT. Methods A transcendental phenomenological study design guided by the conceptual framework of the BCEi (Quality of Life Model Applied to Breast Cancer [QOL-BC]) was used. A purposive and snowball sample of YAABCS was recruited from AL, LA, and MS. The study recruitment flyer was disseminated online and via email through breast cancer-affiliated organizations and support groups. Word-of mouth dissemination was also encouraged. Data collected included two semi-structured interviews, a sociodemographic survey, volunteered personal effects from YAABCS, and field/reflective notes. Data were analyzed using NVivo11 Software (qualitative data) and IBM SPSS Software v. 23 (quantitative data), then validated among participating YAABCS. Early Results Early results of the ongoing dissertation study were informed by 7 of 15 YAABCS (mean age= 32 years; mean survivorship= 4 years). These YAABCS perceived survivorship as a labile, new normal. Feeling as though survivorship was a burden, YAABCS described the need to be “strong” for themselves and others. These women actively structured their lives to manage changes to their physical, psychological, social, and spiritual selves. While YAABCS reported successful survivorship management to co-survivors and others, they acknowledged that survivorship was an ongoing “struggle” in which spirituality and survivorship education were key. Discussion/Conclusion Early results indicated a fluid and complex experience of survivorship among YAABCS. While most reported an intensive need for spiritual connection, all reported a need for more comprehensive survivorship education. Thus, a tailored survivorship education intervention may be needed for YAABCS. Future Directions The ongoing dissertation study to adapt Y-AMBIENT will be informed by the lived experience of young African American breast cancer survivorship. Future research examining YAABCS's perceptions of the BCEi and the inter-relation of QOL-BC constructs may inform this and future interventions that aim to decrease quality of life health disparities among YAABCS. Acknowledgements This research is funded by an American Cancer Society Doctoral Degree Scholarship in Cancer Nursing (DSCN-15-073-01), Susan G. Komen Graduate Traineeship in Disparities Research, Jonas Nurse Leaders Scholarship, and Gladys Farmer Colvin Doctoral Fellowship. Citation Format: Timiya S. Nolan, Tiffany L. Carson, Susan Davies, Comfort Enah, Nataliya Ivankova, Karen Meneses. Exploring the lived experience of young African American breast cancer survivorship: Early results toward informing a psychoeducational intervention. [abstract]. In: Proceedings of the Ninth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2016 Sep 25-28; Fort Lauderdale, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2017;26(2 Suppl):Abstract nr B18.

601 metal-on-metal total hip replacements with 36 mm heads a 5 minimum year follow up: Levels of ARMD remain low despite a comprehensive screening program

BackgroundWe conducted a retrospective study to assess the clinical outcome, failure rate, and reason for failure of a large consecutive series of 36mm MoM Corail/Pinnacle total hip replacements (THRs). MethodsBetween 2006 and 2011, 601 consecutive 36mm MoM THRs were performed (585 patients). Patients were followed according to the UK Medicines and Healthcare Products Regulatory Agency (MHRA) guidelines. All patients were accounted for and 469 patients (78%) were clinically and radiographically assessed. 328 females and 141 males with a median age of 73 (range 36–94 years) and a median follow up of 7.2 years (range 5.2–9.7 years) were followed. Clinical data included blood cobalt and chromium, Oxford Hip Score (OHS), plain radiograph, ultrasound of hip and intra-operative findings in those patients who had revision surgery. Results56 patients died of causes unrelated to their hip replacement. The mean survivorship of the implant was 92.8% (range 91.6–94%, 95% CI) at a median time to follow up of 84 months (62–113 months).The functional outcome was good with a median OHS of 38 out of 48 (23–44). The dislocation rate was 0.99%, with all these 6 cases requiring revision.476 patients had blood tests. 100 patients (21%) had elevated levels of either cobalt above MHRA guidelines of 7 parts per billion (120 and 135nmol/L respectively for cobalt and chromium). Cobalt was elevated independently of chromium in 75% of the cases (but never vice versa).The mean cup inclination angle was 42°. Each incremental stem size increase resulted in a decrease in cobalt by 11nmol/L.The most common reason for revision was adverse reaction to metal debris (ARMD) (12 cases). ConclusionThis paper is the largest and longest follow up of 36mm MoM THRs. Using the MHRA guidelines for follow up, the revision rates of this cohort has remained low compared to other studies, but unacceptably higher than that of other bearing surfaces. Level of evidenceIII.

Underserved community-based walking program for breast cancer survivors.

e288 Background: Advancements in early detection and new treatment options have improved outcomes for breast cancer survivors (BCS). With increased survivorship, improving quality of life (QOL) may be a challenge for some women. Exercise improves QOL for BCS and decreases recurrence, but, despite this many women do not routinely exercise. Underserved areas are at particular risk. Few studies have examined factors influencing exercise initiation and maintenance in underserved areas among minority overweight women. The purpose of this mixed methods study was to examine physiological outcomes and motivational factors in a community-based goal oriented walking program for BCS. Methods: A convenience sample of female BCS was recruited from an inner-city community center 12-week walking program. Women participated in physiological testing and focus groups before and after the program. Data was collected regarding strength, fitness, quality of life, and motivation of the women. Quantitative data was analyzed with paired t-tests. Two researchers independently analyzed focus groups’ transcriptions and like statements and phrases were coded. Themes emerged after discussions between the researchers. Results: The 13 participants [overweight BMI (n = 2), and obese BMI (n = 11)] had a mean survivorship of 5.4 years (range .25-14.5) years. Only 7 participants completed both pre and post physiological testing. Functional endurance significantly improved as indicated by the 6 Minute Walk Test (pre = 503(56), post = 570 (63) meters, mean(sd)), p = 0.02). While overall QOL did not improve, functional well-being showed significant improvement. Two focus group sessions were held at the beginning (n = 13) and end (n = 11) of the program. Themes emerged identifying 1) Treatment Weight Gain, 2) Familial Support, 3) Not Wanting to Go it Alone, 4) The Team Made the Difference Conclusions: Female BCS spoke of interpersonal and environmental factors involved in the decision to engage and maintain exercise with the walking program. Further research is needed to examine exercise motivation in underserved, overweight and obese breast cancer survivors.

Spinifex–mallee revegetation: implications for restoration after mineral-sands mining in the Murray–Darling Basin

Mineral-sands mining in the semiarid and arid zone of south-eastern Australia is now a widespread disturbance that may adversely affect large areas of remnant vegetation, including mallee (Eucalyptus spp.) with hummock grass or spinifex (Triodia scariosa) understorey. No broad-scale restoration projects have been undertaken to revegetate mallee Eucalyptus species with spinifex. We report on the survivorship and relative importance (spatial coverage) of hand-planted tubestock 10 years after establishment in 2001, which included mallee Eucalyptus, Triodia scariosa, Acacia spp. and Hakea spp. These taxa are the dominant plants in a semiarid dune–swale system on a former mineral-sands mine licence area in semiarid, north-western Victoria. Mean survivorship of tubestock was 0.58 ± 0.04. Spinifex (Triodia scariosa), needlewood (Hakea) and several mallee species (Eucalyptus spp.) survived substantially better than the average of all tubestock-planted species, although Acacia spp. had low survivorships. Although the plantings were undertaken in the early stages of the most severe drought in the instrumental record (the ‘Millennium drought’), several taxa survived well and species such as spinifex established and developed ground coverage greater than the benchmark values for the ecological vegetation class of the location. We conclude that hand-planting of tubestock can achieve restoration objectives for this component of spinifex–mallee vegetation, even under extremely arduous conditions associated with long-term drought. We also herald the importance of taking a long-term view to the assessment of revegetation success, in this case 10 years.

The Survival Analysis in Third-Generation Ceramic-On-Ceramic Total Hip Arthroplasty

A total of 527 patients (577 hips) who underwent primary THA using third-generation ceramic-on-ceramic (CoC) articulation were retrospectively reviewed. They were followed up for an average of 5.9years. Seven hips experienced liner fracture and 14 hips experienced head fracture. Squeaking occurred in eight hips. The revision rate in this study was 5.2%, but excluding the cases of ceramic head and liner fracture, there were nine cases (1.6%) of revision surgery. Considering revision for any reason as the end point, mean survivorship was 93% at 10years. According to the femoral head size and neck length, 28mm head with short neck has the worst survivorship of 89% at 10years. Overall, our study showed a higher rate of ceramic fracture compared with other studies.

Better survival of total knee replacement in patients older than 70 years: a prospective study with 8 to 12 years follow-up.

Modern knee designs have popularized its use in younger patients due to its better performance. There remains uncertainty whether higher demands of these patients can affect implant survivorship. To assess whether modern knee designs have provided similar results in patients younger than 70 years versus older patients. We included 203 consecutive patients (236 knees) who underwent knee replacement for osteoarthritis with a mean follow-up of 11.4 years (range: 8.8 to 12). The mean age was 70 years (range: 31 to 85). Knee replacements were stratified into two groups: 109 were younger than 70 years and 127 were older than 70 years (70 years of age is the mandatory retirement age). There were no significant pre-operative differences between groups with regards to knee alignment, alpha or beta angles, knee score or function score. Fourteen implants were radiographically loose at last follow up visit. Groups were matched in terms of demographic data. We found that patients older than 70 years had significantly better mean survivorship at 12 years. (97% vs. 88%; P=0.010). Patients under 70 years presented with a higher rate of polyethylene wear which was further associated with radiolucent lines in the femur and tibia as well as the presence of osteolysis. There was also an association between migration and presence of osteolysis. Patients over 70 years old undergoing cemented total knee replacement for osteoarthritis showed better implant survivorship versus patients under 70 years old.

Revision of Type III and Type IVB Acetabular Defects With Burch–Schneider Anti-Protrusio Cages

Extensive bone loss in severe acetabular deficiencies can make repair with acetabular shells impossible. We retrospectively analyzed mid-term to long-term results of acetabular revision with Burch–Schneider reinforcement cages in 33 hips in patients with a mean age of 59.03years after a mean follow-up period of 6.19years. Under the American Academy of Orthopaedic Surgeons classification, 9 patients had type III acetabular bone defects and 24 had type IVB. Merle D’Aubigné scores improved by a mean of 9.3 points. The prosthesis failure rate was 15.1%, the series complication rate was 21.2%, and the mean survivorship was 11.57years. The Burch–Schneider cage is useful for reconstruction in massive acetabular deficiency, but complication rates are high and long-term mechanical failure is a concern.

Post-settlement survivorship in two Caribbean broadcasting corals

The post-settlement phase of broadcast-spawned coral life histories is poorly known due to its almost complete undetectability and, hence, presumed low abundance in the field. We used lab-cultured settled polyps of two important Caribbean reef-building species with negligible larval recruitment to quantify early post-settlement survivorship (6–9 weeks) over multiple years/cohorts and differing orientation on a reef in the Florida Keys. Orbicella faveolata showed significantly and consistently better survivorship in vertical rather than horizontal orientation, but no discernable growth overall. Meanwhile, Acropora palmata showed no significant difference in survivorship between orientations, but significantly greater growth in the horizontal orientation. Both species showed significant variation in mean survivorship between cohorts of different years; 0–47 % for O. faveolata and 12–49 % for A. palmata over the observed duration. These results demonstrate wide variation in success of cohorts and important differences in the larval recruitment capacities of these two important but imperiled reef-building species.

A retrospective medium- to long-term results of 1500 AGC total knee replacements – An independent centre functional follow up and survivorship

BackgroundThe AGC knee is one of the most widely used knee replacements in the world with good survivorship in national joint registries, including the Swedish within which it remains the gold standard of risk. PurposeHowever, there are few long term survivorship reviews from the centre other than those affiliated with the designer that also offer any insight into functional outcome. In this review, we present the results of one of the largest non-designer, medium- to long term follow-ups of the AGC knee replacement. MethodsA total of 1538 AGC knees were performed during a 15 year period, of which 902 were followed up by postal or telephone questionnaire using Oxford Knee Scores, Visual Analogue Scores (VASs) of function and pain and survival analysis. Results87.5% of patients reported excellent or good functional reports at final follow up and 90.3% reporting excellent or good pain scores.There is a mean survivorship of 95.88% at 15 years from the 1538 knees. 85.7% of patients had an Oxford score of between 12 and 40, with 71.2% scoring between 0 and 30. 65.6% of patients responded with a VAS of 0 or 1 at rest (minimum pain = 0) and 53.9% reported a VAS of 0 or 1 while walking. InterpretationOur study shows excellent mid to long term results in a large group of patients was achieved using the AGC TKR implanted by a variety of Consultants and trainee surgeons.This review and data from national registries suggest that in terms of both survivorship and function demonstrate the AGC knee replacement still remains the knee that newer designs must be measured against.

Long-Term Implant Survivorship of Cementless Total Knee Arthroplasty: A Systematic Review of the Literature and Meta-Analysis

Cementless total knee arthroplasty (TKA) has had limited use in the United States, however, recent reports have demonstrated promising results, but there has been no meta-analysis to examine these outcomes in the past 5 years. In this review, 37 studies (2,940 patients and 3,568 TKAs) were identified and used, comparing cementless to cemented TKA. Pooled implant survivorship was compared using a fixed-effect meta-analysis between cementless and cemented TKA, and between cementless TKA with and without screw fixation. Cementless TKA had implant survivorship comparable to cemented TKA (odds ratio, 1.1; 95% confidence interval [CI], 0.62-2.00). The mean survivorship at 10 years for cementless TKA was 95.6% compared with 95.3% for cemented TKA. At 20-year follow-up, implant survivorship decreased to 76 and 71%, respectively. No difference was observed between fixation with or without screws (OR, 1.1; 95% CI, 0.16-7.5). Implant survivorship for cementless TKA was comparable to the current gold standard cemented TKAs.

Femoral impaction grafting

Femoral impaction grafting is a reconstruction option applicable to both simple and complex femoral component revisions. It is one of the preferred techniques for reconstructing large femoral defects when the isthmus is non-supportive. The available level of evidence is primarily derived from case series, which shows a mean survivorship of 90.5%, with revision or re-operation as the end-point, with an average follow-up of 11 years. The rate of femoral fracture requiring re-operation or revision of the component varies between several large case series, ranging from 2.5% to 9%, with an average of 5.4%.

Advantages and disadvantages of ceramic on ceramic total hip arthroplasty: A review

Ceramic on ceramic (COC) total hip arthroplasty (THA) was developed to reduce wear debris and accordingly, the occurrence of osteolysis and aseptic loosening especially in younger patients. Based on the excellent tribological behavior of current COC bearings and the relatively low biological activity of ceramic particles, significant improvement in survivorship of these implants is expected. We used manual search to identify all relevant studies reporting clinical data on COC THAs in PubMed. The objective was to determine whether current COC THA offers a better clinical outcome and survivorship than non-COC THA. Studies with early generation ceramic bearings yielded 68% to 84% mean survivorship at 20 years follow-up which is comparable with the survivorship of non-COC THAs. Studies on current ceramic bearings report a 10-year revision-free interval of 92% to 99%. These outcomes are comparable to the survivorship of the best non-COC THAs. However, there are still concerns regarding fracture of sandwich ceramic liners, squeaking, and impingement of the femoral neck on the rim of the ceramic liner leading to chipping, especially in younger and physically active patients. Current COC THA leads to equivalent but not improved survivorship at 10 years follow-up in comparison to the best non-COC THA. Based on this review, we recommend that surgeons weigh the potential advantages and disadvantages of current COC THA in comparison to other bearing surfaces when considering young very active patients who are candidates for THA.

Susceptibility of Oriental Fruit Moth (Lepidoptera: Tortricidae) to Two Pyrethroids and a Proposed Diagnostic Dose of Esfenvalerate for Field Detection of Resistance

Laboratory colonies of oriental fruit moth, Grapholita molesta (Busck) (Lepidoptera: Tortricidae), were reared on 'Gala' apples (Malus pumila Mill.) and lima bean (Phaseolus lunatus L.) diet. Neonates were placed on wheat germ diet containing a range of concentrations of esfenvalerate or lambda-cyhalothrin; mortality was assessed after 96 h. For a long-term laboratory colony, LC50 values of esfenvalerate and lambda-cyhalothrin were 0.35 and 0.12 ppm, respectively, for progeny of insects reared on apples. For a colony established from Calhoun Co., IL, in 2007, LC50 values of esfenvalerate and lambda-cyhalothrin were 0.37 and 0.10 ppm, respectively, for progeny of insects reared on apples. LC50 values of these insecticides did not differ significantly for either colony when progeny of insects reared on lima bean diet were tested. We observed no consistent evidence of pyrethroid resistance in the Calhoun colony after laboratory culture for 21-23 generations. We described the dose-response relationship for esfenvalerate applied topically in 1 microl of acetone to male moths from the long-term laboratory colony and estimated the LD99 to be 0.022 microg per moth. Application of 0.022 microg of esfenvalerate per moth to approximately 600 male moths from two putatively susceptible populations resulted in mean survivorship approximately equal to the expected level of 1.0%. Application of the same dose to 374 field-captured moths from two Calhoun Co. orchards with histories of pyrethroid use resulted in mean survivorship of 9.4 and 82%. We propose that 0.022 microg of esfenvalerate in 1 microl of acetone can be used as a diagnostic dose for monitoring pyrethroid resistance in oriental ruit moth in the field.

Population biology of sugar pine ( Pinus lambertiana Dougl.) with reference to historical disturbances in the Lake Tahoe Basin: Implications for restoration

Historical logging, fire suppression, and an invasive pathogen, Cronartium ribicola, the cause of white pine blister rust (WPBR), are assumed to have dramatically affected sugar pine ( Pinus lambertiana) populations in the Lake Tahoe Basin. We examined population- and genetic-level consequences of these disturbances within 10 sugar pine populations by assessing current population structure and trends for 1129 individuals, genetic diversity for 250 individuals, and frequency of WPBR-resistance for 102 families. Logging had occurred in 9 of 10 sites and fire suppression was evident in all stands. High density of white fir ( Abies concolor) is often an indicator of fire suppression and we found a negative relationship between sugar pine survivorship and white fir basal area ( r 2 = 0.31). C. ribicola was present in 90% of stands (incidence range: 0–48%) and we found a significant relationship between mean host survivorship and disease incidence ( r 2 = 0.46). We estimated population growth rates ( λ) from size-based transition matrices. For six of 10 sugar pine populations λ was ⩾1.0, indicating that these populations appear to be stable; for four populations, λ was <1.0, indicating populations that may be in decline. A population specific drift parameter, c i , which is a measure of genetic differentiation in allele frequencies relative to an ancestral population, ranged from 0.009 to 0.048. Higher values of c i indicate greater genetic drift, possibly due to a bottleneck caused by historical logging, other agents of mortality or much older events affecting population sizes. Effects of drift are known to be greater in small populations and we found a negative relationship between sugar pine density and c i ( r 2 = 0.36). Allele frequency of the Cr1 gene, responsible for WPBR-resistance in sugar pine, averaged 0.068 for all populations sampled; no WPBR infection was found in one population in which the Cr1 frequency was 0.112. Historical disturbances and their interactions have likely influenced the population biology of sugar pine in the Tahoe Basin; for some populations this has meant reduced population size, higher genetic drift, and poor survival of small- and intermediate-sized individuals. Possible management strategies include restoring population numbers, deploying WPBR-resistance, treating stands to promote natural sugar pine regeneration, and enhancing genetic diversity.

Fire tolerance of perennial grass tussocks in a savanna woodland

AbstractGrass populations in tropical savannas are highly resilient in relation to different fire regimes, but the mechanisms conferring such resilience have been poorly studied. Here we examine one such mechanism, high adult survival during fire, for three perennial grass species in an Australian savanna: Eriachne triseta Nees ex Steud, Eriachne avenacea R.Br and Chrysopogon latifolius S.T.Blake. The study examined survivorship after 3 years, at plots subject to experimental fire regimes (experiencing 0, 1, 2 or 3 fires over the study period) at the Territory Wildlife Park near Darwin in the Northern Territory, Australia. Mean survivorship was 79.9%, 64.3% and 62.0% for E. avenacea, E. triseta and C. latifolius respectively. For the two species of Eriachne, mean survivorship was highest (E. avenacea, 94.6%; E. triseta, 77.1%) in unburnt plots, whereas survivorship of C. latifolius was highest (71.7%) under highest fire frequency. However, variation in survivorship among fire regime treatments was not statistically significant for any of the study species. This negligible difference in survivorship among regimes points to fire tolerance (sprouting ability) as an important mechanism contributing to the resilience and persistence of perennial grasses in these savannas.

Estimating western corn rootworm (Coleoptera: Chrysomelidae) larval susceptibility to event DAS‐59122‐7 maize

Susceptibility of Diabrotica virgifera virgifera (LeConte) larvae to DAS-59122-7 maize was evaluated using a laboratory technique that measures rootworm survival to adulthood on maize seedlings. This method produces direct measures of larval susceptibility using realistic exposure to the same range of insecticidal protein concentrations found in field-grown DAS-59122-7 maize roots. First, second and third instars were reared to adulthood on DAS-59122-7 maize seedlings or a non-transgenic, near-isoline maize. Data on survival, adult gender ratio, adult weight and median emergence were collected. Overall, larval susceptibility to DAS-59122-7 maize was lower than earlier predictions (Storer et al. 2006). Neonate survival on DAS-59122-7 maize was approximately 33% of isoline survival after 17 days, and the same 33% recovered and developed to adulthood when the isoline maize was substituted. Survival rate on DAS-59122-7 maize increased with instar. The mean survivorship was 0.5%, 26% and 65% when exposure to DAS-59122-7 maize began at the first, second and third instars, respectively. Exposure to DAS-59122-7 maize led to sub-lethal effects on adult gender ratio, weight and median emergence. These effects decreased when exposure to DAS-59122-7 maize began at later instars. The killing effect of DAS-59122-7 maize on rootworm larvae appeared to result from the combined chronic effects and absence of a suitable host as perceived by the larvae. The relevance of these data and the methodology of estimating rootworm susceptibility to plant-incorporated protectants are discussed in the context of the US Environmental Protection Agency’s functional definition of ‘high dose’ and use of refuge for resistance management (EPA 1998a). Based on these results it is evident that DAS-59122-7 maize does not meet the functional definitions of high dose as described by EPA (1998a,b) and ILSI (1999), and the utility of refuge, refuge size and refuge placement for delaying rootworm resistance should be further investigated.

Determinants of successful groundcover restoration in forests of the Southeastern United States

Restoration is a time-consuming and expensive endeavour. As such, it is a field that could benefit immensely from the adoption of an adaptive management approach, where knowledge gained from previous experiences is incorporated into future planning efforts. However, meta-analyses that synthesise results obtained over large spatial scales are rarely conducted, hindering the ability of restoration practitioners to learn from mistakes and successes of others. We present a case study of groundcover restoration in the southeastern United States as an example of the wealth of information that can be obtained from a synthesis of existing data. This example is characteristic of many restoration endeavours in that a large number of decisions must be made during the restoration process. We used Classification and Regression Trees (CART) to identify those restoration activities that most often lead to successful groundcover establishment in forests of the Southeastern US. The most important factors in determining mean survivorship of plants established through outplanting included planting season, the presence of existing canopy cover, and the use of prescribed fire after planting. These three factors alone explained 28% of the variation in mean survivorship (pPRE = 0.28, model PRE = 0.32). In contrast, the single greatest predictive variable in the establishment density of seeds sown on restoration sites was the use of herbicide prior to planting which explained 30% of the variation in establishment rate (pPRE = 0.30, model PRE = 0.38). Based on these analyses, we describe simple, discrete recommendations that should improve the survival and establishment of native plant species in restoration sites across the southeastern coastal plain of the US. We also discuss the utility of CART in distilling large volumes of existing data into easily interpretable recommendations.