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This Element presents a framework for analyzing the complexities of contracting, how these vary across circumstances, the ways contract managers can address challenges, and the skills of contract managers. The framework is grounded on central concepts. Market frictions are underlying imperfections that cause common contracting problems; contract management activities are the tasks and procedures that contract managers perform to prepare and execute the purchase; and skills are the ability to perform contract management activities that identify and mitigate frictions. These concepts are interdependent – market frictions can influence the efficacy of contract management activities, activities may reduce or increase the presence of frictions, and skills may influence both the choice and effectiveness of activities in addressing contracting challenges. Omitting any of these components is likely to result in misleading accounts of the root causes and potential solutions to contracting challenges.
The music of J. S. Bach clearly had a powerful impact on Claude Debussy. As a student, Debussy studied figured bass and fugue, and even performed several pieces by Bach, such as the Chromatic Fantasy and Fugue in D minor and Toccata and Fugue in G minor. Later in his career, he signed a contract with Durand in April 1915 to edit several chamber works by Bach, completing one for the six sonatas for violin and keyboard (BWV 1014–1019) in April 1917 around the same time as his own Sonata for Violin and Piano. Although Debussy did not explicitly quote any material from Bach’s music in his Violin Sonata, this chapter examines some of the ways in which the former inspired him when composing the latter. These include favouring highly decorated melodic lines, creating complex contrapuntal textures, especially those involving parallel voice leading, and disguising the movement’s formal structure.
The primary significance of scientific theories, laws, models, etc. lies in how they enable prediction and control of some part of the world that interests us. Pragmatists see this as the whole story with science; science is problem-solving inquiry that helps us when our habitual anticipations and practices fail us. What scientific inquiry delivers is new modes of prediction and control that resolve such problematic situations. Further talk of “pure” science, of the role of “explanatory virtues” beyond the empirical and practical, the pragmatist is wont to dismiss as “quasi-religious” and metaphysical claptrap. All of this is right, except the dismissiveness and the epithet “claptrap.” There is a perfectly pragmatic account to be given of this other (genuine and important) element of science, and it depends on taking seriously the social and personal role of religion and mythos. We may need science to play a key role in this secular age: providing synoptic understanding of the place of humanity in the universe and the meaning of it all. This suggests complex criteria for the synthetic and visionary parts of science that can fulfill this role.
Everyday functional capacity in older adults is influenced by several factors, with prior studies finding that cognition mediates the relationship between depression and everyday functioning. However, these studies utilized samples with low depression severity and used only one type of functional assessment. We aimed to examine whether cognition mediates the relationship between depression and functioning in older adults with a history of treatment-resistant depression.
Method:
Data from 383 participants enrolled in the OPTIMUM Neuro study were analyzed. Participants completed a neuropsychological assessment battery, depression severity interview, self-/informant-rated functioning measures and a performance-based functioning measure. Linear regression was used to determine whether depression scores predicted cognitive domain and everyday functioning scores. Cognitive domain scores predicted by depression were then tested as mediators between depression and functioning.
Results:
Higher depression symptoms predicted poorer performance on all measures of functioning as well as the cognitive domains of attention, executive functioning, and immediate memory. Immediate memory partially mediated the relationship between depression and a performance-based measure of functioning, while attention and executive functioning partially mediated the relationship between a self-report measure of functioning and depression.
Conclusions:
The relationship between depression severity and poorer functional performance was partially mediated by attention, executive functioning, and immediate memory, with results differing based on the measure of functioning used. Our findings suggest that there may be additional non-cognitive factors influencing this relationship and highlight the importance of using multiple methods to assess functional performance.
The Hector Galaxy Survey is a new optical integral field spectroscopy (IFS) survey currently using the Anglo-Australian Telescope to observe up to 15 000 galaxies at low redshift ($z \lt 0.1$). The Hector instrument employs 21 optical fibre bundles feeding into two double-beam spectrographs, AAOmega and the new Spector spectrograph, to enable wide-field multi-object IFS observations of galaxies. To efficiently process the survey data, we adopt the data reduction pipeline developed for the SAMI Galaxy Survey, with significant updates to accommodate Hector’s dual-spectrograph system. These enhancements address key differences in spectral resolution and other instrumental characteristics relative to SAMI and are specifically optimised for Hector’s unique configuration. We introduce a two-dimensional arc fitting approach that reduces the root-mean-square (RMS) velocity scatter by a factor of 1.2–3.4 compared to fitting arc lines independently for each fibre. The pipeline also incorporates detailed modelling of chromatic optical distortion in the wide-field corrector, to account for wavelength-dependent spatial shifts across the focal plane. We assess data quality through a series of validation tests, including wavelength solution accuracy (1.2–2.7 km s$^{-1}$ RMS), spectral resolution (FWHM of 1.2–1.4 Å for Spector), throughput characterisation, astrometric precision ($\lesssim$ 0.03 arcsec median offset), sky subtraction residuals (1–1.6% median continuum residual), and flux calibration stability (4% systematic offset when compared to Legacy Survey fluxes). We demonstrate that Hector delivers high-fidelity, science-ready datasets, supporting robust measurements of galaxy kinematics, stellar populations, and emission-line properties and provide examples. Additionally, we address systematic uncertainties identified during the data processing and propose future improvements to enhance the precision and reliability of upcoming data releases. This work establishes a robust data reduction framework for Hector, delivering high-quality data products that support a broad range of extragalactic studies.
Admission to shared hospital rooms are a risk factor of healthcare-associated (HA) SARS-CoV-2. Quantifying the impact of engineering controls such as ventilation and filtration is essential to informing resource utilization and infection prevention guidelines.
Methods:
Multicenter test-negative study of patients exposed to SARS-CoV-2 in shared rooms across five hospitals between January and October, 2022. Independent variables tested were measured air changes per hour (ACH), presence of any room mechanical ventilation (RMV), or portable high-efficiency particulate air (HEPA) filter. Covariates included facility (number of beds in room, outbreak status of unit), source patient (presence of symptoms, RT-PCR cycle threshold (Ct) value), and exposed patient factors (age, sex, time from last SARS-CoV-2 vaccine, previous SARS-CoV-2 infection, exposure duration). Multilevel logistic mixed models used to estimate the impact of engineering controls on transmission.
Results:
Among 468 exposed patients, secondary attack rate was 26.3% (range 7.5–33.3% across hospitals). In multivariable analysis, increased ACH was associated with decreased odds of infection (adjusted odds ratio (aOR) 0.88, 95% CI 0.78–1.00; p=.046) as were exposure duration and Ct value of source patient. Presence of RMV was also associated with decreased odds of infection (aOR 0.51, 95% CI 0.27–0.95; p=.034) while use of portable HEPA filter was not significant (aOR 0.58, 95% CI 0.26–1.31; p=.18).
Conclusions:
Improved ventilation was independently associated with lower odds of SARS-CoV-2 infection among exposed roommates. Ensuring RMV is present and optimizing ACH may significantly mitigate the risk of HA-SARS-CoV-2. Future prospective studies should assess optimal ACH thresholds and the impact of portable HEPA filters.
Understanding the developmental and occupational histories of Ancestral Maya settlements is crucial for interpreting their roles in broader social, political, and economic dynamics. This article presents 62 new accelerator mass spectrometry (AMS) 14C dates from residential groups in the outlying settlement zone at Alabama, a major inland Ancestral Maya center in East-Central Belize. Alabama is a rare example of a “boomtown” in the Maya lowlands, experiencing rapid development primarily during the 8th and 9th century CE, corresponding to the Late to Terminal Classic periods. Using Bayesian stratigraphic sequence models, we construct detailed developmental and occupational histories for the townsite, clarifying the timing of its development, occupation, and abandonment. Our analysis reveals complex residential histories, confirming a rapid tempo of Late and Terminal Classic settlement growth and indicating continuities in occupation into the 10th century CE and beyond. Furthermore, we identify two separate periods of occupation during the Early Classic (cal AD 345–545) and the Late Postclassic (cal AD 1325–1475), demonstrating that parts of the settlement were inhabited at different intervals over many centuries. These results offer the first detailed deep-history perspective for the East-Central Belize region, establishing a framework that addresses challenges in chronology-building posed by poor pottery preservation and the complexities of earthen-core architecture at the site and enabling future chronological modeling in this lesser-known frontier of the eastern Maya lowlands.
Conditioning on variables affected by treatment can induce post-treatment bias when estimating causal effects. Although this suggests that researchers should measure potential moderators before administering the treatment in an experiment, doing so may also bias causal effect estimation if the covariate measurement primes respondents to react differently to the treatment. This paper formally analyzes this trade-off between post-treatment and priming biases in three experimental designs that vary when moderators are measured: pre-treatment, post-treatment, or a randomized choice between the two. We derive nonparametric bounds for interactions between the treatment and the moderator under each design and show how to use substantive assumptions to narrow these bounds. These bounds allow researchers to assess the sensitivity of their empirical findings to priming and post-treatment bias. We then apply the proposed methodology to a survey experiment on electoral messaging.
Signal detection theory (SDT; Tanner & Swets in Psychological Review 61:401–409, 1954) is a dominant modeling framework used for evaluating the accuracy of diagnostic systems that seek to distinguish signal from noise in psychology. Although the use of response time data in psychometric models has increased in recent years, the incorporation of response time data into SDT models remains a relatively underexplored approach to distinguishing signal from noise. Functional response time effects are hypothesized in SDT models, based on findings from other related psychometric models with response time data. In this study, an SDT model is extended to incorporate functional response time effects using smooth functions and to include all sources of variability in SDT model parameters across trials, participants, and items in the experimental data. The extended SDT model with smooth functions is formulated as a generalized linear mixed-effects model and implemented in the gamm4R package. The extended model is illustrated using recognition memory data to understand how conversational language is remembered. Accuracy of parameter estimates and the importance of modeling variability in detecting the experimental condition effects and functional response time effects are shown in conditions similar to the empirical data set via a simulation study. In addition, the type 1 error rate of the test for a smooth function of response time is evaluated.
Edited by
Paul A. Banaszkiewicz, Queen Elizabeth Hospital and North East NHS Surgical Centre (NENSC), Gateshead,Kiran Singisetti, Queen Elizabeth Hospital, Gateshead Health NHS Foundation Trust
This guides a candidate in the generality of how to prepare for Section 1 of the FRCS(Tr&Orth) exam. It will provide an overview of the exam, marking scheme and build up to the exam. Reading resources and tactics to increase a candidate’s score.
Edited by
Paul A. Banaszkiewicz, Queen Elizabeth Hospital and North East NHS Surgical Centre (NENSC), Gateshead,Kiran Singisetti, Queen Elizabeth Hospital, Gateshead Health NHS Foundation Trust
This chapter will guide a candidate in core hand topics that regularly appear in Section 1 of the FRCS(Tr&Orth) exam. The chapter deals with hand questions providing high quality clinical based SBA questions. Detailed explanations of the SBA options with a clear logical approach to selecting the most appropriate option.
Migrants and refugees face elevated risks for mental health problems but have limited access to services. This study compared two strategies for training and supervising nonspecialists to deliver a scalable psychological intervention, Group Problem Management Plus (gPM+), in northern Colombia. Adult women who reported elevated psychological distress and functional impairment were randomized to receive gPM+ delivered by nonspecialists who received training and supervision by: 1) a psychologist (specialized technical support); or 2) a nonspecialist who had been trained as a trainer/supervisor (nonspecialized technical support). We examined effectiveness and implementation outcomes using a mixed-methods approach. Thirteen nonspecialists were trained as gPM+ facilitators and three were trained-as-trainers. We enrolled 128 women to participate in gPM+ across the two conditions. Intervention attendance was higher in the specialized technical support condition. The nonspecialized technical support condition demonstrated higher fidelity to gPM+ and lower cost of implementation. Other indicators of effectiveness, adoption and implementation were comparable between the two implementation strategies. These results suggest it is feasible to implement mental health interventions, like gPM+, using lower-resource, community-embedded task sharing models, while maintaining safety and fidelity. Further evidence from fully powered trials is needed to make definitive conclusions about the relative cost of these implementation strategies.
Accelerating COVID-19 Treatment Interventions and Vaccines (ACTIV) was initiated by the US government to rapidly develop and test vaccines and therapeutics against COVID-19 in 2020. The ACTIV Therapeutics-Clinical Working Group selected ACTIV trial teams and clinical networks to expeditiously develop and launch master protocols based on therapeutic targets and patient populations. The suite of clinical trials was designed to collectively inform therapeutic care for COVID-19 outpatient, inpatient, and intensive care populations globally. In this report, we highlight challenges, strategies, and solutions around clinical protocol development and regulatory approval to document our experience and propose plans for future similar healthcare emergencies.
This article explores the financial and geopolitical networks behind the independence of Gran Colombia. It shows that the failure to obtain official British government support for independence was compensated for by the development of a network of private individuals and partnerships that supplied large quantities of arms, equipment and men. A Colombian government document granting ‘Powers’ to London intermediaries was crucial to the construction of this network. We analyse who the key players were and how the network operated. By exploring the decisions and actions of merchants through the lens of risk, trust, credit and networks, we provide a fresh insight into the wider process of independence in Gran Colombia.
This chapter explores the fascination with things Japanese (the term japonisme was first coined in 1872), which manifested itself in many ways, not least through the collecting of objets d’art – an obsession of Debussy’s. It will examine other ‘orientalisms’ and the role of the Exposition Universelle of 1889 in promoting them. This chapter intersects with Debussy’s interests in a number of ways. His attendance at the Exposition Universelle was seminal to his future development, not least in alerting him to musical cultures remote from his own. However, whilst we can hear the influence of these experiences in his music, Debussy was also a fanatical collector and browser of shops specialising in exotic products. He would often spend housekeeping money on objects for his collection, much to the despair of his partners. This chapter reflects changing consumption in France.
In the decades since his death, Debussy has become a cultural icon – a symbol of music’s modernity. He has been immortalised by a monument in the Bois de Boulogne in Paris, a museum in his hometown of Saint-Germain-en-Laye, and a bust in the Théâtre national de l’Opéra-Comique. His portrait even appeared on a twenty-franc banknote. Over the past few years, Debussy’s stock has only risen. In 2011, New York Times critic Anthony Tommasini ranked him the fifth greatest composer of all time, behind Bach, Beethoven, Mozart, and Schubert. This chapter ranges widely over many aspects of Debussy’s reputation and legacy.
Unlike operatic and orchestral music, chamber music, in common with song, thrived in the salons and the Société nationale. It was a rich period for chamber-music composition, with many works establishing a distinctively French style for genres like the string quartet (just as the French symphony came to distinguish itself from German models). Debussy was at his least idiosyncratic in his one published string quartet, which may be seen as an attempt to conform to expectations, at least in some aspects of the genre. Late in life he chose to distil the most personal features of his style in six chamber works, which pay tribute to remote French traditions, even though only three of these works were completed. The chapter concludes with a consideration of some of the attempts to complete Debussy’s incomplete set of six sonatas, of which he lived to complete only three.
Previous studies have found deficits in imaginative elaboration and social inference to be associated with agenesis of the corpus callosum (ACC; Renteria-Vasquez et al., 2022; Turk et al., 2009). In the current study, Thematic Apperception Test (TAT) responses from a neurotypical control group and a group of individuals with ACC were used to further study the capacity for imaginative elaboration and story coherence.
Method:
Topic modeling was employed utilizing Latent Diritchlet Allocation to characterize the narrative responses to the pictures used in the TAT. A measure of the difference between models (perplexity) was used to compare the topics of the responses of individual participants to the common core model derived from the responses of the control group. Story coherence was tested using sentence-to-sentence Latent Semantic Analysis.
Results:
Group differences in perplexity were statistically significant overall, and for each card individually (p < .001). There were no differences between the groups in story coherence.
Conclusions:
TAT narratives from persons with ACC were normally coherent, but more conventional (i.e., more similar to the core text) compared to those of neurotypical controls. Individuals with ACC can make conventional social inferences about socially ambiguous stimuli, but are restricted in their imaginative elaborations, resulting in less topical variability (lower perplexity values) compared to neurotypical controls.
OBJECTIVES/GOALS: Super refractory status epilepticus (SRSE) is associated with high mortality, often due to withdrawal of life sustaining therapy (WLST) based on perceived poor neurological prognosis. Factors influencing decision making are underreported and poorly understood. We surveyed clinicians who treat SRSE to identify factors that influence WLST. METHODS/STUDY POPULATION: Health care providers (HCP), including physicians, pharmacists, and advanced practice providers, who treat SRSE answered a 51-question survey on respondent demographics, institutional characteristics and SRSE management that was distributed though professional societies. Respondents described approaches to prognostication and rated the importance of clinical factors in the management of two hypothetical clinical cases followed by their prediction of recovery potential for the same two cases. Neurointensivists and other HCP responses were compared using descriptive statistics to differentiate group characteristics; a p-value <0.05 was considered significant. Logistical regression models were employed to identify associations between clinician specific factors and prognostication. RESULTS/ANTICIPATED RESULTS: One-hundred and sixty-four respondents were included in the analysis. Compared to other HCPs (neurologists, epileptologists, neurosurgeons, other intensivists; n=122, 74%), neurointensivists (n=42, 26%) [Odds ratio (OR) 0.3, 95% confidence interval (CI) 0.14-0.68), p=.004)] were less likely to use prognostic severity scores and were less likely to prognosticate likelihood of good functional recovery (OR: 0.28 (95% CI: 0.13-0.62), p=.002) compared to non-neurointensivist HCPs, controlling for potential confounders including professional degree, years of experience, country of practice, and annual volume of SRSE cases. There was, however, significant overlap in factors deemed necessary for determining futility in care escalation. DISCUSSION/SIGNIFICANCE: Neurointensivists value similar clinical factors to other HCPs when evaluating medical futility in SRSE but are less likely to predict definitive outcomes. Pending final survey results, future studies aimed at understanding why neurointensivists may be less likely to decisively prognosticate (i.e. avoiding nihilism) in SRSE may be warranted.