Nonlinear life table response experiment analysis: Decomposing nonlinear and nonadditive population growth responses to changes in environmental drivers.

Life table response experiments (LTREs) decompose differences in population growth rate between environments into separate contributions from each underlying demographic rate. However, most LTRE analyses make the unrealistic assumption that the relationships between demographic rates and environmental drivers are linear and independent, which may result in diminished accuracy when these assumptions are violated. We extend regression LTREs to incorporate nonlinear (second-order) terms and compare the accuracy of both approaches for three previously published demographic datasets. We show that the second-order approach equals or outperforms the linear approach for all three case studies, even when all of the underlying vital rate functions are linear. Nonlinear vital rate responses to driver changes contributed most to population growth rate responses, but life history changes also made substantial contributions. Our results suggest that moving from linear to second-order LTRE analyses could improve our understanding of population responses to changing environments.

Inclusive Fitness May Explain Some but Not All Benefits Derived from Helping Behavior in a Cooperatively Breeding Bird.

AbstractIn cooperative breeding systems, inclusive fitness theory predicts that nonbreeding helpers more closely related to the breeders should be more willing to provide costly alloparental care and thus have more impact on breeder fitness. In the red-cockaded woodpecker (Dryobates borealis), most helpers are the breeders' earlier offspring, but helpers do vary within groups in both relatedness to the breeders (some even being unrelated) and sex, and it can be difficult to parse their separate impacts on breeder fitness. Moreover, most support for inclusive fitness theory has been positive associations between relatedness and behavior rather than actual fitness consequences. We used functional linear models to evaluate the per capita effects of helpers of different relatedness on eight breeder fitness components measured for up to 41 years at three sites. In support of inclusive fitness theory, helpers more related to the breeding pair made greater contributions to six fitness components. However, male helpers made equal contributions to increasing prefledging survival regardless of relatedness. These findings suggest that both inclusive fitness benefits and other direct benefits may underlie helping behaviors in the red-cockaded woodpecker. Our results also demonstrate the application of an underused statistical approach to disentangle a complex ecological phenomenon.

Comparison of Gait and Functional Outcomes Between Open and Arthroscopic Treatment of Adolescent and Young Adult Femoroacetabular Impingement.

BACKGROUND: Management of femoroacetabular impingement (FAI) through an arthroscopic or surgical hip dislocation (SHD) approach has been shown to have similar clinical success and patient-reported outcomes. However, there are limited data comparing functional outcomes. The purpose of this study was to compare gait and functional outcomes of adolescent/young adult patients with FAI treated by either an arthroscopic or open SHD approach. METHODS: We identified prospectively enrolled adolescent/young adult patients (≤20 years old) who underwent surgical treatment for FAI through an SHD or arthroscopic approach. Participants were evaluated in a movement science lab preoperatively and postoperatively (minimum 8 months postoperatively) with barefoot walking and a 30-second single-limb balance trial on the affected side. Participants also completed the Harris Hip Score at the same timepoints. Differences from preoperative to postoperative were determined using a paired-samples t test for each surgical technique, and differences between the SHD and arthroscopic groups were determined using an independent samples t test (α=0.05). RESULTS: Fifty-five participants (42F, 16.2±1.4 y) were tested and grouped by surgical intervention. The SHD and arthroscopy groups consisted of 28 and 27 participants, respectively, with no significant difference between the SHD and arthroscopic cohorts in age (16.4±1.2 vs. 15.9±1.5 y, respectively, P =0.218) or sex distribution (78.6% vs. 74.1% females, respectively, P =0.75). Each group demonstrated significant postoperative improvement in Harris Hip Score (SHD: 64.8±16.4 to 81.8±17.8; arthroscopy: 57.0±16.7 to 84.7±19.7; preoperatively to postoperatively, respectively, both P <0.001). During gait, increased maximum hip flexion was observed following surgical intervention for the SHD group (32.3±5.7 vs. 36.1±5.2, P =0.003). No other clinically significant changes were detected in the SHD or arthroscopic groups preoperatively to postoperatively in trunk, pelvis, or hip kinematics in the coronal plane. During the balance task, neither cohort demonstrated markers of clinically significant abductor dysfunction. However, post operatively, the arthroscopy group was able to balance longer than the SHD group (18.8±7.8 vs. 14.2±2.7 s, respectively, P =0.008), although no differences were detected in trunk or pelvis position in the coronal plane during balance. CONCLUSIONS: Both open SHD and arthroscopic treatment of FAI resulted in improved clinical outcomes with no clinically significant abductor dysfunction 1 year post operatively. However, further study is needed to determine whether more dynamic tasks can potentially elicit subtle differences between the groups. LEVELS OF EVIDENCE: Level II-prospective study.

Treatment of Delbet II/III Pediatric Femoral Neck Fractures With Proximal Femoral Locking Plate Versus Cannulated Screws.

INTRODUCTION: Complications following operative treatment of pediatric femoral neck fractures include nonunion, coxa vara, and avascular necrosis (AVN). Proximal femoral locking plates (PFLPs) provide a fixed-angle construct that may reduce the rates of coxa vara, but their use in pediatric femoral neck fractures has not been studied. The purpose of this study was to evaluate rates of union, coxa vara, and AVN in traumatic pediatric femoral neck fractures treated with PFLP or cannulated screws (CS). METHODS: We retrospectively reviewed all traumatic, nonpathologic Delbet II/III femoral neck fractures in patients below 18 years of age treated with PFLP or CS. All cases had ≥6 months of radiographic follow-up to evaluate for osseous union and AVN. Changes in proximal femoral alignment were determined by measuring injured and contralateral femoral neck-shaft angle and articulotrochanteric distance (ATD) between 6 and 12 months postoperatively. RESULTS: Forty-two patients were identified with mean age at surgery of 10.7±2.9 years (range 3.3 to 16.3 years) and mean follow-up of 36±27 months. Sixteen patients (38%) underwent PFLP fixation, whereas 26 patients (62%) underwent CS fixation. When compared with the CS cohort, the PFLP cohort had a greater proportion of males (87.5% vs. 50%, P =0.02) and Delbet III fractures (68.8% vs. 15.4%, P <0.001). There was no difference between PFLP and CS cohorts with respect to rates of union (81% vs. 88%, respectively, P =0.66), AVN (25% vs. 35%, respectively, P =0.73), or secondary surgery (62% vs 62%, P =0.95). There was no significant difference in neck-shaft angle between injured and contralateral hips in those patients treated with PFLP ( P =0.93) or CS ( P =0.16). However, the ATD was significantly decreased in hips treated with CS compared with the contralateral hip (18.4±4.6 vs. 23.3±4.2 mm, P =0.001), with no significant difference in the PFLP group ( P =0.57). CONCLUSIONS: This study suggests that the use of a PFLP in Delbet II/III femoral neck fractures does not appear to significantly increase nonunion rates or AVN and maintains anatomic ATD when compared with screw fixation. LEVEL OF EVIDENCE: Level III-therapeutic study.

Does Screening Ultrasound Timing in Developmental Dysplasia of the Hip Need to be Adjusted for Moderate Preterm and Near-term Infants: A Prospective Study.

INTRODUCTION: An initial screening ultrasound is essential for patients at higher risk of developmental dysplasia of the hip (DDH) due to breech presentation or a family history of DDH. The American Academy of Pediatrics recommends screening ultrasounds to be performed after 6 weeks of age to reduce the rate of false positives. However, there is limited evidence regarding whether these screening ultrasounds need to be adjusted for gestational age in prematurity. The purpose of this study was to evaluate the influence of moderate preterm and near-term births on screening hip ultrasounds for high-risk DDH populations. METHODS: We identified all prospectively enrolled patients in a single-center database referred for screening hip ultrasound for DDH. We included those hips referred for risk factors of DDH, including breech presentation, family history of DDH, or hip click, and excluded those with known dysplasia or referral for hip instability. Each ultrasound was measured by a pediatric radiologist to determine the alpha angle and femoral head coverage. Patients were classified as "premature" if born at <37 weeks gestation or "full term" if born at ≥37 weeks gestation. All patients underwent screening hip ultrasound between 5 and 8 weeks of age. Sonographic markers of dysplasia and the incidences of abnormal ultrasound and Pavlik harness treatment were compared between cohorts. Significance was set at P <0.05. RESULTS: A total of 244 hips in 122 patients were included, 58 hips in the premature cohort and 186 hips in the full-term cohort. The premature cohort had a significantly decreased gestational age compared with the full-term cohort (35.4 ± 1.1 vs 38.5 ± 1.1 wk, respectively, P < 0.001). However, there was no difference between premature and full-term cohorts in sex distribution (69% vs 75%, females, P = 0.39), unadjusted age at the time of ultrasound (6.6 ± 0.7 vs 6.8±0.7 wk, respectively, P = 0.07), or referral reason ( P = 0.14). On hip ultrasound, there was no difference between premature and full-term cohorts with respect to alpha angle (62.6 ± 3.3 vs 62.2 ± 5.3 degrees, P = 0.41), femoral head coverage (54.9 ± 6.3 vs 55.1 ± 10.6, P = 0.19), rate of abnormal ultrasound (18.3% vs 20.7%, respectively, P = 0.68), or the rate of Pavlik harness treatment (0% vs 5.3%, respectively, P = 0.12). DISCUSSION: There was no significant difference in alpha angle or femoral head coverage between premature and full-term patients at 5 to 8 weeks of unadjusted age. This preliminary data suggests that screening ultrasounds can be performed without adjusting for prematurity. LEVEL OF EVIDENCE: Level II, prognostic study.

Engineering Hydroxylase Activity, Selectivity, and Stability for a Scalable Concise Synthesis of a Key Intermediate to Belzutifan.

Biocatalytic oxidations are an emerging technology for selective C-H bond activation. While promising for a range of selective oxidations, practical use of enzymes catalyzing aerobic hydroxylation is presently limited by their substrate scope and stability under industrially relevant conditions. Here, we report the engineering and practical application of a non-heme iron and α-ketoglutarate-dependent dioxygenase for the direct stereo- and regio-selective hydroxylation of a non-native fluoroindanone en route to the oncology treatment belzutifan, replacing a five-step chemical synthesis with a direct enantioselective hydroxylation. Mechanistic studies indicated that formation of the desired product was limited by enzyme stability and product overoxidation, with these properties subsequently improved by directed evolution, yielding a biocatalyst capable of >15,000 total turnovers. Highlighting the industrial utility of this biocatalyst, the high-yielding, green, and efficient oxidation was demonstrated at kilogram scale for the synthesis of belzutifan.

Conflicting constraints on male mating success shape reward size in pollen-rewarding plants.

PREMISE: Pollen-rewarding plants face two conflicting constraints: They must prevent consumptive emasculation while remaining attractive to pollen-collecting visitors. Small pollen packages (the quantity of pollen available in a single visit) may discourage visitors from grooming (reducing consumptive loss) but may also decrease a plant's attractiveness to pollen-collecting visitors. What package size best balances these two constraints? METHODS: We modeled the joint effects of pollinators' grooming behaviors and package size preferences on the optimal package size (i.e., the size that maximizes pollen donation). We then used this model to examine Darwin's conjecture that selection should favor increased pollen production in pollen-rewarding plants. RESULTS: When package size preferences are weak, minimizing package size reduces grooming losses and should be favored (as in previous theoretical studies). Stronger preferences select for larger packages despite the associated increase to grooming loss because loss associated with nonremoval of smaller packages is even greater. Total pollen donation increases with production (as Darwin suggested). However, if floral visitation declines or packages size preference increases with overall pollen availability, the fraction of pollen donated may decline as per-plant pollen production increases. Hence, increasing production may result in diminishing returns. CONCLUSIONS: Pollen-rewarding plants can balance conflicting constraints on pollen donation by producing intermediate-sized pollen packages. Strictly pollen-rewarding plants may have responded to past selection to produce more pollen in total, but diminishing returns may limit the strength of that selection.

Biotic and anthropogenic forces rival climatic/abiotic factors in determining global plant population growth and fitness.

Multiple, simultaneous environmental changes, in climatic/abiotic factors, interacting species, and direct human influences, are impacting natural populations and thus biodiversity, ecosystem services, and evolutionary trajectories. Determining whether the magnitudes of the population impacts of abiotic, biotic, and anthropogenic drivers differ, accounting for their direct effects and effects mediated through other drivers, would allow us to better predict population fates and design mitigation strategies. We compiled 644 paired values of the population growth rate (λ) from high and low levels of an identified driver from demographic studies of terrestrial plants. Among abiotic drivers, natural disturbance (not climate), and among biotic drivers, interactions with neighboring plants had the strongest effects on λ However, when drivers were combined into the 3 main types, their average effects on λ did not differ. For the subset of studies that measured both the average and variability of the driver, λ was marginally more sensitive to 1 SD of change in abiotic drivers relative to biotic drivers, but sensitivity to biotic drivers was still substantial. Similar impact magnitudes for abiotic/biotic/anthropogenic drivers hold for plants of different growth forms, for different latitudinal zones, and for biomes characterized by harsher or milder abiotic conditions, suggesting that all 3 drivers have equivalent impacts across a variety of contexts. Thus, the best available information about the integrated effects of drivers on all demographic rates provides no justification for ignoring drivers of any of these 3 types when projecting ecological and evolutionary responses of populations and of biodiversity to environmental changes.

Abduction Bracing Following Anterior Open Reduction for Developmental Dysplasia of the Hip Does Not Improve Residual Dysplasia or Reduce Secondary Surgery.

BACKGROUND: Abduction bracing is commonly used following open reduction and spica casting of developmental dysplasia of the hip. However, there is little evidence to support or refute this practice that carries associated cost and burden for families. The purpose of this study was to determine the efficacy of abduction bracing after open reduction in improving the acetabular dysplasia and reducing the rate of secondary surgery for residual dysplasia. METHODS: This is a retrospective study of patients treated with open reduction at a single tertiary referral center. Demographic data, severity of dislocation [International Hip Dysplasia Institute (IHDI) class], age at reduction, and casting duration were obtained. Patients were prescribed no bracing, part-time (≤18 h/d), or full-time (≥20 h/d) brace wear based on surgeon preference. Acetabular index (AI) measurements were obtained at cast removal and at 2- and 4-year follow-up. RESULTS: A total of 146 hips underwent open reduction with 61% (89/146) of hips treated with abduction bracing. There was no difference between braced and nonbraced cohorts with regards to sex, age at time of reduction, dislocation severity, cast duration, immediate postcasting AI, or incidence of medial open reduction. There was no difference in hips treated with or without brace following open reduction with regards to AI at 2 years postreduction (31.8±6.7 vs. 30.4±6.1 degrees, P =0.27) or at 4 years postreduction (24.9±6.5 vs. 24.7±6.5 degrees, P =0.97). However, further analysis showed lower mean AI at 2-year follow-up for braced versus nonbraced patients following medial open reduction (30.0±5.7 vs. 34.5±7.0 degrees, P =0.02). This difference was no longer present at 4-year follow-up (26.6±6.8 vs. 24.2±6.6 degrees, P =0.44). However, 4/19 (21%) nonbraced hips underwent secondary surgery for residual dysplasia and were consequently excluded from the AI measurement at 4 years postreduction (compared with 4/39 [10%] braced hips within the same time period). There was no difference in the rate of secondary surgery between braced and nonbraced hips (30% vs. 33%, respectively, P =0.70). Multivariate analysis demonstrated that neither IHDI classification, bracing, nor age at reduction predicted residual dysplasia. CONCLUSIONS: Abduction bracing following anterior open reduction for developmental dysplasia of the hip is not associated with decreased residual dysplasia at 2/4 years postreduction or with decreased secondary surgery. These results suggest that abduction bracing following anterior open reduction may not provide clinical benefit. However, abduction bracing may be beneficial following medial open reduction. A prospective study is necessary to provide more definitive recommendations. LEVEL OF EVIDENCE: Level III-therapeutic study.

The Significance of Isolated Hip Click as a Sign of DDH: Implications on Referral Guidelines.

BACKGROUND: The clinical significance of an isolated hip click remains unclear. The rates of developmental dysplasia of the hip (DDH) in those referred for hip click vary from 0% to 28%. The purpose of this study was to evaluate the rate of DDH in patients prospectively referred for isolated hip click. METHODS: We prospectively enrolled patients referred to a single pediatric orthopaedic center with concern for DDH secondary to isolated hip click felt by the pediatrician on examination. Patients with known sonographic abnormalities or risk factors for DDH (breech presentation or positive family history) were excluded. Ultrasounds were obtained upon initial presentation and defined as abnormal if alpha angle <60 degrees and/or femoral head coverage (FHC) <50%. Mild dysplasia, analogous to Graf IIa physiological immaturity, was defined as alpha angle 50<α<60 and/or <50% FHC in a patient <3 months age. Severe dysplasia was defined as ≤33% FHC, which has been proposed to be sonographically consistent with a hip dislocation. RESULTS: Two hundred fifty-five children were referred for isolated hip click. One hundred eighty-nine patients (74%) had normal ultrasound whereas 66 patients (26%) had sonographic abnormalities (mean age 6.5±6.2 wk at initial ultrasound). Fifty patients (19.6%) demonstrated physiological immaturity, 3 patients (1.2%) demonstrated moderate sonographic dysplasia, and 13 patients (5.1%) had sonographic findings consistent with severe dysplasia or dislocated hip. Hips with severe dysplasia were younger than the remaining population (2.8±2.4 wk vs. 6.6±6.2 wk, P <0.001) with no difference in sex distribution ( P =0.07) or first-born birth order ( P =0.36). For those with sonographic abnormality, 18 (27%) patients were treated with Pavlik harness, 1 (2%) was treated with abduction orthosis, and the remainder (71%) were observed for resolution of physiological immaturity. CONCLUSIONS: Infants with isolated hip click identified by their pediatrician may have higher rates of dysplasia than previously reported. We recommend screening ultrasound and/or orthopaedic referral for all infants with isolated hip click. LEVEL OF EVIDENCE: Level II-prospective prognostic study.

The Role of the Artery of Ligamentum Teres in Revascularization in Legg-Calve-Perthes Disease.

INTRODUCTION: A recent cadaveric study supported that most immature hips are supplied by the artery of ligamentum teres and suggested this medial vascular source may influence the pattern of revascularization in Legg-Calve-Perthes disease (LCPD). The purposes of this study were to characterize the perfusion pattern of the capital femoral epiphysis and determine the role of the artery of ligamentum teres in early revascularization of LCPD. METHODS: Retrospective review of perfusion magnetic resonance imaging (pMRI) from 64 hips in early stage LCPD (Waldenström stage I to IIa) was performed. Two independent graders categorized perfusion pattern based on the presence of perfusion medially (from artery of ligamentum teres) and/or laterally (from the medial femoral circumflex artery) on coronal and sagittal MRI series: type 1-lateral perfusion only, type 2-separate medial and lateral perfusion, or type 3-coalescent medial and lateral perfusion. Lateral pillar classification was obtained for hips that reached mid-fragmentation. RESULTS: We identified 64 patients (75% male) with mean age at diagnosis of 8.5±2.1 years. 36% (23/64) hips underwent pMRI during stage I and 64% (41/64) during stage IIa. pMRI revealed separate and distinct medial and lateral sources of perfusion (type 2) in 50% (32/64) hips. In stage I, the distribution of type 1/2/3 hips was found to be 26%/52%/22%. However, in stage IIa there was a nonsignificant trend toward greater coalescence of the medial and lateral perfusion with a distribution of type 1/2/3 of 7%/49%/44% (P=0.07). There was a nonsignificant trend toward weak negative linear correlation between lower initial perfusion grade and worsened lateral pillar classification at mid-fragmentation (r=-0.25, P=0.05). CONCLUSION: The presence of separate and distinct areas of perfusion of medial and lateral capital femoral epiphysis provides further evidence of the role of the ligamentum teres vessels in revascularization during the early stages of LCPD. The changes in perfusion pattern with disease progression likely reflect that medial femoral circumflex artery and ligamentum teres vessel revascularization occur separately, but ultimately coalesce posteriorly over time. LEVEL OF EVIDENCE: Level II-prognostic study.

The Clinical Significance of Infolded Limbus on Postreduction Arthrogram in Developmental Dysplasia of the Hip.

BACKGROUND: The purpose of this study was to investigate whether presence of an infolded limbus on hip arthrogram at index closed reduction was associated with increased residual dysplasia or secondary surgery. METHODS: We retrospectively reviewed all patients who underwent closed reduction for dysplasia of the hip with a minimum 2-year follow-up between 1980 and 2016. Demographic data was obtained including the age at reduction and severity of dislocation based on the International Hip Dysplasia Institute (IHDI) classification. Arthrograms performed at time of closed reduction were separately reviewed by 3 fellowship-trained pediatric orthopaedic surgeons to evaluate for an infolded limbus. The primary radiographic outcome was acetabular indices at 2 and 4 years postreduction. We also assessed the presence of avascular necrosis and rate of secondary reconstructive surgery for residual dysplasia. RESULTS: A total of 182 hips in 165 patients underwent closed reduction at a mean age of 9.8±4.5 mo and were followed a mean of 9.0±4.9 y. An infolded limbus was identified in 20.3% (37/182) hips with substantial agreement among the 3 graders (Fleiss κ=0.75). The frequency of labral infolding increased with the severity of dislocation (8.8%% of IHDI II, 26.7% IHDI III, and 25.0% of IHDI IV hips; P=0.03). Hips with infolded limbus were older at reduction (12.4±5.3 vs. 9.2±5.8 mo, P=0.001). The mean acetabular index was higher in hips with infolded limbus than hips without at 2 years postreduction (34.8±4.8 vs. 32.6±5.8 degrees, respectively; P=0.04). However, multivariate analysis revealed that only the severity of dislocation predicted dysplasia at 2 years postreduction. No significant difference in acetabular index was seen at 4 years postreduction (27.2±7.4 vs. 25.4±6.5 degrees, P=0.24). There was no difference in avascular necrosis between groups (P=0.74). There was no difference in rate of secondary surgery between hips with labral infolding and those without (35% vs. 30%, respectively; P=0.52). CONCLUSIONS: An infolded limbus was more common in older patients with more severe dislocations. However, it is not associated with increased residual dysplasia or secondary surgery and may have limited utility in decision-making during closed reduction. LEVEL OF EVIDENCE: Level II-prognostic study.

Does the Deformity Index Reliably Predict the Shape of the Femoral Head at Healing of Legg-Calvé-Perthes Disease?

BACKGROUND: Treatment of Legg-Calvé-Perthes disease (LCPD) aims to preserve the spherical shape of the femoral head. The deformity index (DI) <0.3, measured 2 years from disease onset, is a surrogate measure that predicts that the femoral head will be Stulberg class I or II at skeletal maturity. There is no study that compares the predictive value of DI against a quantitative measure of the shape of the femoral head when the disease heals. We undertook this study to assess the reproducibility of a new method of measurement of DI and see if DI could predict the shape of the femoral head when the disease healed. METHODS: DI was measured 2 years after disease onset and the Sphericity Deviation Score (SDS) was measured at healing of LCPD on radiographs of 43 children. Reproducibility of measurement was tested. Each healed femoral head was classified as spherical or aspherical based on subjective visual assessment. The DI values were compared with SDS values. RESULTS: The reproducibility of measurement of SDS was excellent and superior to that of DI. The mean duration of disease was 3.97±0.96 years. Only 17 of 32 hips with DI values <0.3 at 2 years had spherical femoral heads at healing (SDS <10). Three hips with SDS values <10 had DI values >0.3. The positive and negative predictive values of a DI <0.3 in predicting if the femoral head will be spherical (SDS <10) when the disease healed were 53% and 73%, respectively. CONCLUSION: Though DI can be reproducibly measured the predictive value of a DI <0.3, to accurately identify hips that are likely to heal with spherical femoral heads, is not sufficiently high to justify its use as an outcome measure.

Using data calibration to reconcile outputs from different survey methods in long-term or large-scale studies.

Understanding the impact of management interventions on the environment over decadal and longer timeframes is urgently required. Longitudinal or large-scale studies with consistent methods are best practice, but more commonly, small datasets with differing methods are used to achieve larger coverage. Changes in methods and interpretation affect our ability to understand data trends through time or across space, so an ability to understand and adjust for such discrepancies between datasets is important for applied ecologists. Calibration or double sampling is the key to unlocking the value from disparate datasets, allowing us to account for the differences between datasets while acknowledging the uncertainties. We use a case study of livestock grazing impacts on riparian vegetation in southeastern Australia to develop a flexible and powerful approach to this problem. Using double sampling, we estimated changes in vegetation attributes over a 12-year period using a pseudo-quantitative visual method as the starting point, and the same technique plus point-intercept survey for the second round. The disparate nature of the datasets produced uncertain estimates of change over time, but accounting for this uncertainty explicitly is precisely the objective and highlights the need to look more closely at this very common problem in environmental management, as well as the potential benefits of the double sampling approach.

Teachers' value beliefs and usage of one-to-one devices for students with dyslexia: A descriptive study.

One-to-one devices provide the opportunity for students to develop 21st-century skills, improve academic learning, access information, and increase student independence. This descriptive study explored the value beliefs held by middle school teachers at a school for students with dyslexia (SWD) following the implementation of one-to-one devices and the teachers' technology integration during the instruction of SWD. Data were collected from nine middle school teachers through a survey, classroom observation, and structured interviews. Quantitative findings demonstrated that teachers valued the use of technology in the teaching and learning process and had access to resources and personnel to support technology integration. However, the mean score for the sufficient training for technology integration was found to be lower. The study's qualitative findings revealed (a) one-to-one devices were used as a supplemental resource; (b) technology had both positive and negative impacts, and (c) teachers increased in self-efficacy of technology use within a supportive environment. Based on these findings, extended professional development incorporating 21st-century skills with a focus on the integration of devices into content areas is needed in order to develop the skills and knowledge necessary to incorporate student-centered activities.

Latitudinal gradients in population growth do not reflect demographic responses to climate.

Spatial gradients in population growth, such as across latitudinal or elevational gradients, are often assumed to primarily be driven by variation in climate, and are frequently used to infer species' responses to climate change. Here, we use a novel demographic, mixed-model approach to dissect the contributions of climate variables vs. other latitudinal or local site effects on spatiotemporal variation in population performance in three perennial bunchgrasses. For all three species, we find that performance of local populations decreases with warmer and drier conditions, despite latitudinal trends of decreasing population growth toward the cooler and wetter northern portion of each species' range. Thus, latitudinal gradients in performance are not predictive of either local or species-wide responses to climate. This pattern could be common, as many environmental drivers, such as habitat quality or species' interactions, are likely to vary with latitude or elevation, and thus influence or oppose climate responses.

Aridity weakens population-level effects of multiple species interactions on Hibiscus meyeri.

Predicting how species' abundances and ranges will shift in response to climate change requires a mechanistic understanding of how multiple factors interact to limit population growth. Both abiotic stress and species interactions can limit populations and potentially set range boundaries, but we have a poor understanding of when and where each is most critical. A commonly cited hypothesis, first proposed by Darwin, posits that abiotic factors (e.g., temperature, precipitation) are stronger determinants of range boundaries in apparently abiotically stressful areas ("stress" indicates abiotic factors that reduce population growth), including desert, polar, or high-elevation environments, whereas species interactions (e.g., herbivory, competition) play a stronger role in apparently less stressful environments. We tested a core tenet of this hypothesis-that population growth rate is more strongly affected by species interactions in less stressful areas-using experimental manipulations of species interactions affecting a common herbaceous plant, Hibiscus meyeri (Malvaceae), across an aridity gradient in a semiarid African savanna. Population growth was more strongly affected by four distinct species interactions (competition with herbaceous and shrubby neighbors, herbivory, and pollination) in less stressful mesic areas than in more stressful arid sites. However, contrary to common assumptions, this effect did not arise because of greater density or diversity of interacting species in less stressful areas, but rather because aridity reduced sensitivity of population growth to these interactions. Our work supports classic predictions about the relative strength of factors regulating population growth across stress gradients, but suggests that this pattern results from a previously unappreciated mechanism that may apply to many species worldwide.

Late Hip Dysplasia After Normal Ultrasound in Breech Babies: Implications on Surveillance Recommendations.

BACKGROUND: There is significant controversy in the literature over rates of late-developing dysplasia following normal screening ultrasound in breech babies, with reported rates varying from 7% to 29%. The purpose of this study is to investigate the rates of radiographic dysplasia in breech babies after a normal ultrasound with a minimum of 1 year of radiographic follow-up. METHODS: This study was an institutional review board-approved prospective study of all patients referred by their pediatrician for concern for developmental dysplasia of the hip between July 2008 and August 2014. We identified all subjects with breech presentation and excluded those with an abnormal initial examination/ultrasound or with <12 months of radiographic follow-up. Anterior-posterior pelvis films were obtained after >12 months and acetabular indices (AIs) were measured and compared with contemporary normative data. Dysplasia was diagnosed as >2 SDs above the mean. RESULTS: A total of 654 patients were referred with a history of a breech presentation, and 150 (22.9%) were found to have clinical instability or sonographic evidence of dysplasia on initial presentation and were observed with serial imaging or treated. Of the remaining 504 subjects with a normal clinical examination and screening ultrasound, 133 (26.4%; 74.4% females, 25.6% males) were followed until at least 12 months of age. Of those presenting at age 12 to 14 months, the mean AI was 0.42±0.83 SD above the mean with a skew towards elevated AIs. At the final follow-up (mean: 20.7±6.7 mo), the mean AI was 0.05±0.92 SD above the mean, and only 3/133 (2.2%) patients had a dysplastic hip. No patients underwent treatment other than an observation during the study period. CONCLUSIONS: One in 5 breech babies have dysplasia at presentation, but late dysplasia following normal screening ultrasound may be less common than previously reported and may be due to our prolonged follow-up period. We recommend surveillance of breech babies with follow-up visits after 12 months of age since earlier visits may offer limited benefits. LEVEL OF EVIDENCE: Level II-prospective prognostic study.

Subtle Slipped Capital Femoral Epiphysis Is not Associated With Idiopathic Cam Morphology.

BACKGROUND: The etiology of idiopathic cam morphology remains unclear. One theory suggests that subtle slipped capital femoral epiphysis (SCFE) leads to proximal femoral changes resulting in cam morphology. The purpose of this study was to evaluate the association between subtle SCFE and cam morphology in a large osteological collection. METHODS: We examined 962 cadaveric hips to measure 2 markers of cam morphology, alpha angle and anterior femoral head-neck offset (AHNO), and a validated, objective marker of subtle SCFE deformity (calcar ridge line offset). When the femur is viewed medially, the calcar ridge line extends from the lesser trochanter proximally along the postero-inferior femoral neck and points toward the fovea. In SCFE-like deformity, the fovea deviates posteriorly from this projected line. Pearson correlations were performed to evaluate for possible association of calcar ridge line offset with alpha angle and AHNO. In addition, a multiple regression analysis was performed to determine the influence of age, alpha angle, and AHNO on calcar ridge line offset. RESULTS: There was no clinically relevant association between the calcar ridge line offset and alpha angle (r=-0.02, P=0.58) or AHNO (r=0.08, P=0.012). Furthermore, specimens whose calcar ridge line deviated 1 SD above the mean (more SCFE-like deformity) had a smaller alpha angle (46.6±9.1 vs. 48.3±10.6, P=0.046) and greater AHNO (0.83±0.19 vs. 0.77±0.16, P<0.001), both reflecting less cam-like morphology. On regression analysis, increasing age and increasing AHNO (decreased cam morphology) predicted increased calcar ridge line offset, though the model accounted for only 1.2% of the variance. CONCLUSIONS: Subtle SCFE-like deformity, as objectively measured from the calcar ridge line, was not predictive of more cam-like morphology, and in fact mild opposite associations were found. Further study is needed to identify other potential etiologies of idiopathic cam morphology. CLINICAL RELEVANCE: We present evidence from a large, well-documented osteological collection indicating that subtle SCFE is not associated with idiopathic cam morphology.

The Association of α Angle on Disease Severity in Adolescent Femoroacetabular Impingement.

BACKGROUND: Femoroacetabular Impingement (FAI) is a common cause of hip pain in adolescent patients. Clinical exam and radiographic markers, such as α angle and lateral center edge angle (LCEA), are commonly used to aid in the diagnosis of this condition. The purpose of this study was to correlate preoperative α angle and LCEA with preoperative symptoms, intraoperative findings, and preoperative and postoperative patient reported outcomes (PROs) in the adolescent patient. METHODS: A retrospective analysis of prospectively collected data was conducted for all patients who underwent operative intervention for FAI at an academic institution over an 11-year period. Preoperative imaging was obtained and measured for LCEA and α angle. PROs (modified Harris Hip Score, Hip Disability and Osteoarthritis Outcome Score, and UCLA score) were collected preoperatively, as well as 1, 2, and 5 years postoperatively. Operative intervention was either open surgical hip dislocation or arthroscopic, and intraoperative disease was graded using the Beck Classification system. Patients with minimum 1-year follow-up were included in statistical analysis. RESULTS: There were 86 hips (64 female hips) included with an average age of 16.3 years (range, 10.4 to 20.5 y), with an average of 37 months of follow-up. There was no correlation between severity of preoperative symptoms or difference between pre and postoperative PROs for both α angle and LCEA. Overall, significant improvement was noted in modified Harris Hip Score, Hip Disability and Osteoarthritis Outcome Score, and UCLA Score (P<0.001 for each). Independent of preoperative symptoms, increased α angle correlated with more severe intraoperative labral disease (P<0.001), and longer length of labral tear (Corr 0.295, P<0.01). Femoral head and acetabular articular cartilage damage did not correlate with α angle or LCEA, nor did overall severity of disease. CONCLUSIONS: In adolescent patients with FAI, increased α angle was found to significantly correlate with labral pathology, including increased length of tear and severity of disease, irrespective of preoperative symptoms or postoperative patient reported outcomes. LEVEL OF EVIDENCE: Level III-retrospective.