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Cervical, Thoracic, and Spinopelvic Compensation After Proximal Junctional Kyphosis (PJK): Does Location of PJK Matter?
No full textStudy designRetrospective case series.ObjectiveCompensatory changes above a proximal junctional kyphosis (PJK) have not been defined. Understanding these mechanisms may help determine optimal level selection when performing revision for PJK. This study investigates how varying PJK location changes proximal spinal alignment.MethodsPatients were grouped by upper instrumented vertebrae (UIV): lower thoracic (LT; T8-L1) or upper thoracic (UT; T1-7). Alignment parameters were compared. Correlation analysis was performed between PJK magnitude and global/cervical alignment.ResultsA total of 369 patients were included; mean age of 63 years, body mass index 28, and 81% female, LT (n = 193) versus UT (n = 176). The rate of radiographic PJK was 49%, higher in the LT group (55% vs 42%, P = .01). The UT group displayed significant differences in all cervical radiographic parameters (P r = 0.17) and no significant correlations were noted to SVA, cSVA, or T1S-CL.ConclusionsPJK location influences compensation mechanisms of the cervical and thoracic spine. LT PJK results in increased PT and CL with decreased CTS. UT PJK increases CL to counter increases in T1S with continued T1S-CL mismatch and elevated cSVA
Economic Inequality among Entrepreneurs
No full textPurpose - Drawing from social psychology and economics, I propose several mechanisms that may affect ownership stakes among entrepreneurs, including norms of distributive justice, negotiation constraints, and network constraints. The processes are explored empirically for a representative dataset of entrepreneurial teams. Methodology/Approach - Between 1998 and 2000, entrepreneurial teams were sampled from the U.S. population for the Panel Study of Entrepreneurial Dynamics. I analyze the distribution of ownership stakes at both the individual and group levels. Findings - The results suggest that principles of macrojustice, affecting the distribution of resources in teams as a whole, deviate considerably from principles of microjustice, affecting the resources received by individual entrepreneurs. While aggregate inequality increases in teams that have a diverse set of members, the effect is not reducible to discrimination on the basis of individual status characteristics. Instead, the relational demography of teams - characterized in terms of the degree of closeness in network ties and homogeneity in demographic attributes - serves as a uniquely social predictor of between-group variation in economic inequality. Originality/Value of the paper - Empirical research on inequality has paid little attention to the process of group exchange in organizational start-ups, where entrepreneurs pool resources and skills in return for uncertain or indirect payoffs. This paper offers both theoretical frameworks and empirical analyses to shed light on economic inequality among entrepreneurs
Patterns of Song across Natural and Anthropogenic Soundscapes Suggest That White-Crowned Sparrows Minimize Acoustic Masking and Maximize Signal Content.
No full textSoundscapes pose both evolutionarily recent and long-standing sources of selection on acoustic communication. We currently know more about the impact of evolutionarily recent human-generated noise on communication than we do about how natural sounds such as pounding surf have shaped communication signals over evolutionary time. Based on signal detection theory, we hypothesized that acoustic phenotypes will vary with both anthropogenic and natural background noise levels and that similar mechanisms of cultural evolution and/or behavioral flexibility may underlie this variation. We studied song characteristics of white-crowned sparrows (Zonotrichia leucophrys nuttalli) across a noise gradient that includes both anthropogenic and natural sources of noise in San Francisco and Marin counties, California, USA. Both anthropogenic and natural soundscapes contain high amplitude low frequency noise (traffic or surf, respectively), so we predicted that birds would produce songs with higher minimum frequencies in areas with higher amplitude background noise to avoid auditory masking. We also anticipated that song minimum frequencies would be higher than the projected lower frequency limit of hearing based on site-specific masking profiles. Background noise was a strong predictor of song minimum frequency, both within a local noise gradient of three urban sites with the same song dialect and cultural evolutionary history, and across the regional noise gradient, which encompasses 11 urban and rural sites, several dialects, and several anthropogenic and natural sources of noise. Among rural sites alone, background noise tended to predict song minimum frequency, indicating that urban sites were not solely responsible for driving the regional pattern. These findings support the hypothesis that songs vary with local and regional soundscapes regardless of the source of noise. Song minimum frequency from five core study sites was also higher than the lower frequency limit of hearing at each site, further supporting the hypothesis that songs vary to transmit through noise in local soundscapes. Minimum frequencies leveled off at noisier sites, suggesting that minimum frequencies are constrained to an upper limit, possibly to retain the information content of wider bandwidths. We found evidence that site noise was a better predictor of song minimum frequency than territory noise in both anthropogenic and natural soundscapes, suggesting that cultural evolution rather than immediate behavioral flexibility is responsible for local song variation. Taken together, these results indicate that soundscapes shape song phenotype across both evolutionarily recent and long-standing soundscapes
Model the Hidden Cost of China’s 2060 Carbon Neutrality: Potential Biodiversity Impacts of Wind and Solar Energy Expansion
No full textLarge-scale renewable energy deployments, as urgent solutions to mitigate climate change and its consequences, are reshaping the landscape in the human-environment nexus. Albeit promoted as pathways to bend the curve of biodiversity loss through their emission reduction and habitat restoration potential, renewables require significant land assets per unit energy and could impose high cost to ecosystems, triggering potential conflicts between global climate mitigation and biodiversity conservation. As China expanding its landscape of large-scale wind and solar energy facilities to fulfill its ambitious “2060 Carbon Neutrality” goals, an assessment of the potential areas of such concerns at a high resolution can provide insights for stakeholders to effectively manage biodiversity impacts of renewable power transitions. This project used suitability analysis to identify and predict the potential land use conflict between wind and solar energy expansion and biodiversity conservation in China under the 2060 announced pledge scenario in contrast to the biz-as-usual model of renewables expansion rate. We also quantify the biodiversity impacts of such expansion scenarios by estimating the mean richness and rarity scores, along with ecosystem service values and conflicting zones with Key Biodiversity Areas. Although our results indicated the renewables expansion under China’s ambitious goals tend not to encroach a high ratio of prioritized areas for biodiversity, the potential impacts in regions without the strictest protection are still worth investigation, as illustrated in our case studies for the Qilianshan-Qinghaihu Region and Hainan Province. The study provides insights for decision-makers to develop renewable energy facilities while protecting biodiversity and ecosystem services
Cervical compensatory alignment changes following correction of adult thoracic deformity: a multicenter experience in 57 patients with a 2-year follow-up.
No full textOBJECT Alignment changes in the cervical spine that occur following surgical correction for thoracic deformity remain poorly understood. The purpose of this study was to evaluate such changes in a cohort of adults with thoracic deformity treated surgically. METHODS The authors conducted a multicenter retrospective analysis of consecutive patients with thoracic deformity. Inclusion criteria for this study were as follows: corrective osteotomy for thoracic deformity, upper-most instrumented vertebra (UIV) between T-1 and T-4, lower-most instrumented vertebra (LIV) at or above L-5 (LIV ≥ L-5) or at the ilium (LIV-ilium), and a minimum radiographic follow-up of 2 years. Sagittal radiographic parameters were assessed preoperatively as well as at 3 months and 2 years postoperatively, including the C-7 sagittal vertical axis (SVA), C2-7 cervical lordosis (CL), C2-7 SVA, T-1 slope (T1S), T1S minus CL (T1S-CL), T2-12 thoracic kyphosis (TK), apical TK, lumbar lordosis (LL), pelvic incidence (PI), PI-LL, pelvic tilt (PT), and sacral slope (SS). RESULTS Fifty-seven patients with a mean age of 49.1 ± 14.6 years met the study inclusion criteria. The preoperative prevalence of increased CL (CL > 15°) was 48.9%. Both 3-month and 2-year apical TK improved from baseline (p 0.05 for both). In a subset of patients with a maximum TK ≥ 60° (35 patients) and 3-column osteotomy (38 patients), no significant postoperative cervical changes were seen. CONCLUSION Increased CL is common in adult spinal deformity patients with thoracic deformities and, unlike after lumbar corrective surgery, does not appear to normalize after thoracic corrective surgery. Cervical sagittal malalignment (C2-7 SVA) also increases postoperatively. Surgeons should be aware that spontaneous cervical alignment normalization might not occur following thoracic deformity correction
Comparative analysis of perioperative complications between a multicenter prospective cervical deformity database and the Nationwide Inpatient Sample database.
No full textBackground contextComplication rates for adult cervical deformity are poorly characterized given the complexity and heterogeneity of cases.PurposeTo compare perioperative complication rates following adult cervical deformity corrective surgery between a prospective multicenter database for patients with cervical deformity (PCD) and the Nationwide Inpatient Sample (NIS).Study design/settingRetrospective review of prospective databases.Patient sampleA total of 11,501 adult patients with cervical deformity (11,379 patients from the NIS and 122 patients from the PCD database).Outcome measuresPerioperative medical and surgical complications.MethodsThe NIS was queried (2001-2013) for cervical deformity discharges for patients ≥18 years undergoing cervical fusions using International Classification of Disease, Ninth Revision (ICD-9) coding. Patients ≥18 years from the PCD database (2013-2015) were selected. Equivalent complications were identified and rates were compared. Bonferroni correction (pResultsA total of 11,379 patients from the NIS database and 122 patiens from the PCD database were identified. Patients from the PCD database were older (62.49 vs. 55.15, p.004). Based on surgicalapproach, the PCD reported higher GI and neurologic complication rates for combined anterior-posterior procedures (pConclusionsAnalysis of the surgeon-maintained cervical database revealed higher overall and individual complication rates and higher data granularity. The nationwide database may underestimate complications of patients with adult cervical deformity (ACD) particularly in regard to perioperative surgical details owing to coding and deformity generalizations. The surgeon-maintained database captures the surgical details, but may underestimate some medical complications
Binding site on human immunoglobulin G for the affinity ligand HWRGWV.
No full textAffinity ligand HWRGWV has demonstrated the ability to isolate human immunoglobulin G (hIgG) from mammalian cell culture media. The ligand specifically binds hIgG through its Fc portion. This work shows that deglycosylation of hIgG has no influence on its binding to the HWRGWV ligand and the ligand does not compete with Protein A or Protein G in binding hIgG. It is suggested by the mass spectrometry (MS) data and docking simulation that HWRGWV binds to the pFc portion of hIgG and interacts with the amino acids in the loop Ser383-Asn389 (SNGQPEN) located in the C(H)3 domain. Subsequent modeling has suggested a possible three-dimensional minimized solution structure for the interaction of hIgG and the HWRGWV ligand. The results support the fact that a peptide as small as a hexamer can have specific interactions with large proteins such as hIgG
Three Essays of Bayesian Inference on Dynamical System, Continuous Time Markov Chain, and Low Dimensional Structure
No full textThis dissertation propels the frontier of Bayesian inference, particularly for structurally diverse data, by developing innovative methodologies and robust theories, delineated into three distinct segments, each tackling Dynamical systems, continuous time Markov Chains, and data with low-dimensional structures.The initial part presents the Hierarchical Shrinkage Gaussian Process (HierGP), a novel model adept at detecting structured sparse features within limited data from response surfaces. Incorporating the principles of effect sparsity, heredity, and hierarchy into a Gaussian process framework, HierGP demonstrates superior performance compared to its contemporaries. This superiority is backed by a range of numerical experiments and its successful application to dynamical system recovery.The dissertation's second segment introduces the Bayesian Approximation Spectral Inference (BASI) method. Inspired by the necessity for pragmatic inference techniques for continuous-time Markov chains, BASI innovatively employs probabilistic matrix factorization to estimate a continuous-time Markov chain generator's low-rank representation. This approach effectively circumvents the computational challenges of assessing implicit likelihood functions inherent in previous methods, with our theoretical support for BASI showcased via the asymptotic properties of the posterior distribution.In its final part, the dissertation delves into posterior contraction rates for Gaussian process regression in the context of data with low-dimensional structures. The conditions established enable adaptivity to any intrinsic dimension, thereby giving the optimal posterior contraction rate. This exploration is further enriched by an innovative empirical Bayes prior of bandwidth, dispensing with the necessity for prior knowledge of the intrinsic dimension.Cumulatively, these three essays enhance Bayesian statistics for data with varying and intricate structures. The dissertation seamlessly intertwines theoretical contributions with practical numerical experiments, lending empirical weight to our innovative propositions.</p
Increasing the Engagement of Large Private Forestland Owners in Conservation Management
No full textThe involvement of large private and institutional forestland owners in conservation has been recognized as increasingly important for the successful implementation of landscape-scale conservation. However, public and non-governmental organization partners have found engagement of these landowners in conservation planning, management, and implementation to be a significant challenge. The Nicholas Institute for Policy Solutions at Duke University, the Sustainable Forestry Initiative, Inc., and the U.S. Forest Service hosted three meetings in April, September, and October 2016 to bring together leaders from each of these sectors to brainstorm approaches that could help increase the engagement of large private landowners in conservation. This paper summarizes ideas generated at these “all lands” meetings and provides a few concrete examples of conservation solutions across local and regional scales that could potentially be replicated to encourage large private landowner engagement