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An owner of a firm may choose to hire an unbiased CEO or one with confidence bias. We develop a model that demonstrates that the owner’s optimal choice depends on whether the firm and rival choice variables are strategic substitutes or strategic complements. When choice variables are strategic substitutes or strategic complements for both firms, owners optimize by hiring overconfident CEOs. When choice variables are substitutes for one firm and complements for the rival firm, each firm optimizes by hiring an underconfident CEO. We show that the model applies to price and output competition, advertising, research and development spending, and product design.

The present formative research study reviewed existing literature relating to adolescent rites of passage and initiation ceremonies in East and Southern Africa (ESA), with a focus on Eswatini, Malawi, South Africa and Zambia to assess the impacts of these rites on youth in these countries. Research was conducted entirely online using Google, Google Scholar and the Widener University (US) database. The research found different cultures maintain a range of customs and practices to prepare young people for their roles and responsibilities as adults, and that some initiation practices have negative impacts on the physical, emotional and psychological health and well-being of adolescents. The research supports the conclusion that it is important to have policies and programmes that are designed to protect the rights and welfare of young people in ESA, and that local leaders and stakeholders play invaluable roles in determining and maintaining any changes to existing practices.

Abstract Background Given the demands for public health and infectious disease management skills during COVID-19, a shortage of the public health workforce, particularly with skills and competencies in epidemiology and biostatistics, has emerged at the Centers for Disease Controls (CDCs) in China. This study aims to investigate the employment preferences of doctoral students majoring in epidemiology and biostatistics, to inform policy-makers and future employers to address recruitment and retention requirements at CDCs across China. Methods A convenience sampling approach for recruitment, and an online discrete choice experiment (DCE) survey instrument to elicit future employee profiles, and self-report of their employment and aspirational preferences during October 20 and November 12, 2020. Attributes included monthly income, employment location, housing benefits, children’s education opportunities, working environment, career promotion speed and bianzhi (formally established post). Results A total of 106 doctoral epidemiology and biostatistics students from 28 universities completed the online survey. Monthly income, employment location and bianzhi was of highest concern in the seven attributes measured, though all attributes were statistically significant and presented in the expected direction, demonstrating preference heterogeneity. Work environment was of least concern. For the subgroup analysis, employment located in a first-tier city was more likely to lead to a higher utility value for PhD students who were women, married, from an urban area and had a high annual family income. Unsurprisingly, when compared to single students, married students were willing to forgo more for good educational opportunities for their children. The simulation results suggest that, given our base case, increasing only monthly income from 10,000 ($ 1449.1) to 25,000 CNY ($ 3622.7) the probability of choosing the job in the third-tier city would increase from 18.1 to 53.8% (i.e., the location choice is changed). Conclusion Monthly income and employment location were the preferred attributes across the cohort, with other attributes then clearly ranked and delineated. A wider use of DCEs could inform both recruitment and retention of a public health workforce, especially for CDCs in third-tier cities where resource constraints preclude all the strategies discussed here.

We investigate why a firm might purposefully hire a chief executive officer (CEO) who under- or over-estimates the degree of substitutability between competing products. This counterintuitive result arises in imperfect competition because CEO bias can affect rival behavior and the intensity of competition. We lay out the conditions under which it is profitable for owners to hire biased managers. Our work shows that a universal policy that effectively eliminates such biases need not improve social welfare.

Abstract Introduction Individuals with Down syndrome (DS) have autonomic dysfunction, which impacts heart rate and blood pressure regulation. Initial evidence also suggests an impaired ability to peripherally vasoconstrict during lower body negative pressure (LBNP). Given the relationship between vessel caliber and wave reflection, this may alter central hemodynamics and hemodynamic load. We aimed to investigate aortic hemodynamics and wave reflection during LBNP in individuals with DS and controls. Methods Radial applanation tonometry was performed on 15 individuals with DS (male n = 12, age 24 ± 1 yrs, BMI 29.4 ± 2.0 kg/m2) and 21 control participants (male n = 12, age 24 ± 1 yrs, BMI 24.4 ± 1.0 kg/m2) before, during and after a 5-min LBNP stimulus of –20 mmHg. Waveforms were calibrated to mean and diastolic brachial pressures. Generalized transfer function was used to estimate aortic pressures (systolic aSBP, diastolic aDBP and mean pressure aMAP), augmentation index (Aix), augmentation index normalized for HR (Aix@HR75), augmentation pressure (AP), reflection index (Rix) and forward (Pf) and reflected wave magnitude (Pb). Results Interaction effects were observed for AP, Aix, AIX@75, Rix and Pb (p < 0.05) in which DS had reductions in the outcome during LBNP whereas controls had little or no change. Although trending towards a larger drop in aSBP in individuals with DS, no significant interaction effects were found for aSBP, aDBP, aMAP, HR or Pf in response to LBNP. Conclusion These results show individuals with DS exhibited greater reductions in aortic pressure waveform characteristics and wave reflections in response to LBNP, indicative of reduced sympathetic control resulting in less peripheral vasoconstriction.

Acute inflammation increases the risk of cardiac and cerebrovascular events, potentially associated with altered hemodynamic load. Wave reflection at the aorta and carotid artery can contribute to central hemodynamic load and provide insight into downstream changes in vascular tone. Acute inflammation may reduce wave reflection via downstream vasodilation, however, this is not firmly established and has only been investigated at the aorta. Purpose: Explore the effect of acute inflammation on aortic and carotid hemodynamics and wave reflection. Methods: Twenty-three young adults (26 ± 4 yrs, 22.7 ± 3.2 kg/m2) underwent vascular measures at baseline and 24 h following typhoid vaccine-induced inflammation. Aortic (estimated from radial) and carotid pressure waveforms were obtained via tonometry. Augmentation index and wave separation analyses (WSA) were used to assess wave reflection. Aortic stiffness was estimated from single-point pulse wave velocity (PWV). Carotid beta-stiffness and arterial diameters were assessed via ultrasound. Results: Acute inflammation reduced aortic and carotid wave reflection at 24 h (See Table 1 AIx, Reflection index, p < 0.05). WSA did not reveal independent changes in forward or reflected wave magnitude, time to reflection, PWV, or beta-stiffness (p > 0.05). Brachial and carotid artery diameter increased from 3.79 ± 0.76 to 3.86 ± 0.76 mm (p = 0.055) and 6.44 ± 0.72 to 6.55 ± 0.69 mm (p = 0.04), respectively. Table 1 Aortic Carotid n Baseline 24-h p-value Baseline 24-h p-value SBP, mmHg 23 104 ± 10 104 ± 8 0.88 107 ± 11 107 ± 10 0.98 DBP, mmHg 23 72 ± 8 71 ± 7 0.23 71 ± 8 70 ± 7 0.26 MAP, mmHg 23 86 ± 9 85 ± 7 0.31 86 ± 9 85 ± 7 0.29 Pulse pressure, mmHg 23 32 ± 6 33 ± 8 0.21 36 ± 7 37 ± 8 0.39 AIx, % 23 3 ± 10 −1 ± 10 0.04 −4 ± 15 −9 ± 16 0.04 AIx@75, % 23 −6 ± 12 −9 ± 12 0.048 −13 ± 15 −18 ± 15 0.09 Augmented pressure, mmHg 23 1 ± 3 0 ± 3 0.05 −2 ± 6 −4 ± 7 0.08 Pf, mmHg 22 30 ± 7 31 ± 7 0.40 34 ± 8 36 ± 12 0.07 Pb, mmHg 22 14 ± 3 13 ± 4 0.24 16 ± 3 15 ± 4 0.09 Reflection index, au 22 47 ± 8 44 ± 9 0.04 48 ± 11 43 ± 13 0.01 Time to reflection, ms 22 158 ± 16 161 ± 20 0.20 180 ± 25 185 ± 26 0.53 All data mean ± standard deviation. SBP, systolic blood pressure; DBP, diastolic blood pressure; MAP, mean arterial pressure; AIx, augmentation index; Pf, forward wave magnitude; Pb, reflected wave magnitude. Conclusion: Acute inflammation reduces aortic and carotid wave reflection in young adults, potentially due to downstream vasodilation. Although reduced wave reflection can decrease cardiac workload, reduced wave reflection in the carotid may render the brain vulnerable to pulsatile blood flow. These findings may implicate changes in wave reflections are a contributing mechanism behind acute inflammation-induced cerebrovascular risk.

Introduction: Cardiovascular events are the leading cause of death among firefighters, with the greatest risk occurring during or shortly after fire suppression activity. Increased cardiovascular risk potentially manifests from detrimental changes in ventricular function, vascular load, and their interaction described as ventricular-vascular coupling (VVC). Therefore, our objective was to determine the effect of live-firefighting on ventricular systolic function, vascular load, and VVC. Methods: Forty male (27 ± 6 years, 26.9 ± 4.0 kg·m−2) firefighters completed hemodynamic and cardiac measures before and 10–30 minutes after 3 hours of live-firefighting. Left ventricular function assessed as ejection fraction (EF), fractional shortening (FS), and ventricular elastance (Elv: ESP/end-systolic volume [ESV]) via echocardiography and brachial-estimated ESP. Vascular load assessed as arterial elastance (Ea: end systolic pressure [ESP]/stroke volume [SV]). VVC quantified as the ratio of Ea to Elv and indexed to body surface area (EaI, ElvI). Results: Following firefighting, both EF and FS significantly decreased (p < 0.05) with no change in Elv (p = 0.49) EaI significantly increased (p < 0.01), driven by EDV-mediated decreases in SV (p < 0.05) and unaltered ESP (p = 0.99). These disparate changes resulted in an increase in VVC (p < 0.01) post firefighting. Conclusion: Our findings suggest firefighting does not alter ventricular elastance but increases arterial load among healthy firefighters; resulting in an uncoupling of the heart and vascular systems. This undesirable increase in VVC and concomitant reduction in ventricular systolic function may contribute to increased cardiovascular risk following firefighting. Changes in cardiovascular parameters pre/post firefighting activity Pre Post p Weight* (kg) 88.9 ± 14.0 88.0 ± 14.0

Acute inflammation is associated with increased risk for cardiovascular events and leads to reductions in conduit artery (flow-mediated dilation, FMD) and resistance vessel endothelial function. Whether this dysfunction during acute inflammation is further transmitted down the arterial tree to the microvasculature, inhibiting its ability to dilate or be recruited in response to a hypoxic stimulus, has yet to be investigated. Microvascular function and reactivity can be non-invasively measured using near-infrared spectroscopy (NIRS) during and following an occlusive stimulus. Purpose: To investigate whether acute inflammation impairs microvascular function. Methods: The typhoid vaccine was used to induce acute systemic inflammation in 16 young, healthy adults (8 male, 26.3 ± 3.0 years; 21.7 ± 2.4 kg/m2). Blood pressure, FMD of the brachial artery, and NIRS of the forearm flexor muscles were measured at baseline and 24-h following the vaccination. NIRS was analyzed during a 5-min arterial occlusion to obtain markers of microvascular function and reactivity from the tissue saturation index (TSI): occlusion slope (muscle oxidative capacity); and reperfusion slope, reperfusion magnitude, and peak hyperemic response (microvascular reactivity). Results: Mean arterial pressure did not change during the inflammatory episode (90 ± 9 mmHg to 90 ± 7 mmHg, p = 0.83) and FMD was significantly reduced at 24 h (5.6 ± 2.6% to 4.1 ± 1.7%, p = 0.03). No change was noted in the TSI occlusion slope, reperfusion slope, reperfusion magnitude, or peak hyperemic response (p > 0.05). Conclusion: Vaccination-induced acute inflammation reduced endothelial function. However, no differences were noted in microvascular reactivity or oxidative capacity. Further investigation with a larger sample size is necessary to confirm these results.

Inflammation is associated with an increased risk of cardiovascular events and reduced endothelial function. Higher cardiorespiratory fitness is associated with lower risk of cardiovascular events and improved vascular function. Whether fitness plays a role during acute inflammation is unknown. Purpose: Evaluate the role of fitness in the endothelial response to acute inflammation in younger (YA) and older (OA) adults. Methods: Acute inflammation was induced using influenza vaccine in 23 YA (12 male, 26 ± 4 yrs, 24.0 ± 3.5 kg/m2) and 60 OA (20 male, 65 ± 5 yrs, 27.8 ± 5.0 kg/m2). Blood pressure, flow-mediated dilation (FMD) and inflammatory markers were measured before and 24-hours post-vaccination. VO2peak was measured via a treadmill test. A VO2peak greater than age- and sex-associated 50th percentile according to the American College of Sports Medicine was defined as Fit. Results: Fit OA reduced FMD more than low fit OA (p = 0.02) 24 h post-vaccination. High and low fit YA similarly decreased FMD at 24 h (p = 0.66). YA and high fit OA had a similar reduction (relative %) in FMD (pz0.05). Regression analyses indicated no association between VO2peak and change in FMD (β = −0.01, p = 0.98) in YA, but a significant association existed in OA (β = −0.36, p = 0.04) after adjusting for age, sex, BMI and baseline FMD. YA-high fit YA-low fit OA-high fit OA-low fit n 14 9 16 43 VO2Max, ml/kg/min 48.4 (5.6)* 35.6 (4.9) 32.3 (4.2)* 21.9 (4.3) Baseline SBP 113 (13) 115 (13) 125 (14) 125 (14) Baseline PP 47 (8) 47 (11) 54 (10) 53 (11) Baseline FMD, % 12.4 (2.7) 11.6 (5.5) 7.5 (3.9)* 5.4 (2.5) Baseline CRP, mg/1 1.1 (0.7) 0.6 (0.6) 2.4 (3.3) 2.5 (2.2) Baseline IL-6, pg/ml 1.0 (0.7) 0.8 (0.5) 1.7 (1.4) 1.6 (1.1) Change SBP, mmHg −3 (6) 2 (8) −2 (9) −2 (11) Change PP, mmHg 2 (6) 5 (7) 0 (7) 0 (8) Change FMD, % −3.2 (4.1) −2.3 (5.5) −3.7 (3.8)* −0.2 (3.5) Change CRP, mg/l 1.0 (1.5) 0.9 (0.8) 1.1 (2.2) 0.9 (1.4) Change IL, pg/ml 1.0 (1.5) 1.6 (2.3) 0.8 (2.6) 0.4 (1.0) FMD: flow mediated dilation, CRP: C-reactive protein, IL-6: interleukin-6, SBP: systolic blood pressure, PP: pulse pressure *P < 00.5 vs. low-fit of same age category Conclusion: In OA, higher fitness is associated with a greater decrease in endothelial function during acute inflammation; high fit OA had a similar endothelial response compared to YA. This suggests intact reactivity of the vasculature to inflammatory stress in high fit OA, which may indicate a healthier vessel versus low fit OA.

High-intensity resistance exercise (RE) acutely increases arterial stiffness and blood pressure (BP), coupled with reduced cerebral blood flow velocity (CBFv) and greater flow pulsatility in the cerebral circulation, which may be detrimental to cerebral microvasculature. Because females have different CV control mechanisms, it is important to assess potential sex differences in cerebrovascular responses to acute RE. Purpose: To examine the effect of sex on hemodynamics and cerebral vasculature following acute RE. Methods: Men (n = 18, 27 yrs, BMI = 24.2) and women (n = 14, 25 yrs, BMI = 23.8) performed RE (3 × 10, isokinetic knee flexion/extension). Measurements were obtained at baseline and post-exercise (1, 5, 30-minute). Beat-to-beat heart rate (HR), brachial BP, cardiac output (CO), stroke volume and end-tidal CO2 were collected. CBFv was measured by transcranial Doppler, carotid BP by applanation tonometry and central pulse wave velocity (PWV) by an automated ambulatory BP monitor. Results: Table 1. CBFv pulsatility increased following RE at 1-minute post (p < 0.05) in men and was elevated above baseline 5-minute post-exercise (p < 0.05) in both groups (Figure 1). Mean CBFv increased 1-min post-exercise and decreased below baseline 5-minute post-exercise (p < 0.05) in both sexes. PWV increased 1-minute post-exercise (p < 0.05) in both groups. Variables Baseline 1-minute 5-minute 30-minute Heart Rate(bpm)*† Men 63 ± 9 82 ± 9 71 ± 10 70 ± 8 Women 70 ± 7 93 ± 13 79 ± 10 76 ± 9 CO (L/min) * Men 4.9 ± 0.7 7.9 ± 1.3 6.1 ± 1.3 5.2 ± 0.9 Women 5.4 ± 1.0 8.2 ± 1.4 6.3 ± 1.0 5.7 ± 0.8 SV (ml/min)*‡ Men 77 ± 16ab 95 ± 17bc 85 ± 17c 72 ± 13 Women 80 ± 17a 91 ± 20bc 81 ± 14 76 ± 16 bSBP (mmHg)* Men 124 ± 10 140 ± 12 127 ± 10 127 ± 9 Women 124 ± 9 136 ± 15 122 ± 13 123 ± 9 bDBP (mmHg)* Men 72 ± 8 74 ± 7 72 ± 7 76 ± 6 Women 73 ± 5 76 ± 9 71 ± 7 73 ± 5 bMAP (mmHg)* Men 92 ± 8 100 ± 8 93 ± 8 96 ± 7 Women 95 ± 6 101 ± 11 93 ± 8 95 ± 6 cSBP (mmHg)* Men 120 ± 12 129 ± 18 125 ± 13 126 ± 10 Women 1 22 ± 12 124 ± 13 119 ± 18 123 ± 8 cDBP (mmHg)* Men 75 ± 7 74 ± 7 75 ± 7 79 ± 6 Women 74 ± 6 73 ± 6 75 ± 7 74 ± 5 cMAP (mniHg)* Men 93 ± 8 94 ± 8 94 ± 7 97 ± 7 Women 94 ± 6 93 ± 8 95 ± 9 96 ± 5 PWV (m/s)* Men 5.2 ± 0.5 5.6 ± 0.5 5.4 ± 0.5 5.2 ± 0.3 Women 5.0 ± 0.4 5.3 ± 0.5 5.1 ± 0.3 5.0 ± 0.3 CBFv Mean (cm/s)*† Men 55.8 ± 7.6 63.9 ± 9.6 51.4 ± 6.9 53.7 ± 7.9 Women 69.8 ± 14.4 81.0 ± 23.1 63.7 ± 12.9 65.8 ± 12.0 CBFv Pulsatility Index*†‡ Men 0.91 ± 0.12ab 1.10 ± 0.16* 1.13 ± 0.17c 0.89 ± 0.13 Women 0.81 ± 0.09b 0.90 ± 0.18 0.95 ± 0.13c 0.81 ± 0.11 End-Tidal CO2 (%)* Men 4.86 ± 0.48 5.72 ± 0.66 4.64 ± 0.51 4.51 ± 0.58 Women 4.41 ± 0.60 5.44 ± 0.65 4.26 ± 0.39 4.24 ± 0.50 Table 1All Data are mean ± SD; *Exercise effect, p < 0.05. †Group effect. p < 0.05. ‡Interaction effect. p < 0.05. a Significantly different from 1-minute, b Significantly different from 5-minute. c Significantly different from 30-minute. p < 0.05). Brachial systolic BP (bSBP), brachial diastolic BP (bDBP), brachial mean BP (bMAP), Carotid systolic BP (cSBP),carotid diastolic BP (cDBP), cardiac output (CO), stroke volume (SV) and central pulse wave velocity (PWV), cerebral blood flow velocity (CBFv). Figure 1All Data are mean ± SD, *Exercise effect, p < 0.05. †Group effect, p < 0.05. ‡Interaction effect, p < 0.05. a Significantly different from 1-minute, b Significantly different from 5-minute. c Significantly different from 30-minute, p < 0.05). Conclusion: Men increased CBFv pulsatility at 1-minute post-RE compared to women, demonstrating a sex difference in cerebral vascular reactivity. RE increased central arterial stiffness, mean CBFv, HR, and BP similarly for both sexes. CO was also elevated at 5-minute, but CBFv dropped below baseline and pulsatility continued to rise above baseline. This temporary disruption in cerebral autoregulation may impact brain health in both sexes.

We investigate the welfare effect of union activity in a relatively new oligopoly model, the Cournot-Bertrand model, where one firm competes in output (a la Cournot) and the other firm competes in price (a la Bertrand). The Nash equilibrium prices, outputs, and profits are quite diverse in this model, with the competitive advantage going to the Cournot-type competitor. A comparison of the results from the Cournot-Bertrand model with those found in the traditional Cournot and Bertrand models reveals that firms and the union have a different preference ordering over labor market bargaining. These differences help explain why the empirical evidence does not support any one model of union bargaining. We also examine the welfare and policy implications of union activity in a Cournot-Bertrand setting.

The purpose of this study was to examine the extent to which character familiarity and game interactivity moderate preschoolers’ learning and transfer from digital games. The games were based on a popular television show and designed to test skills related to STEM (science, technology, engineering, mathematics): numerical cognition (quantity of different sets) and knowledge of a biological concept (growth). Preschoolers (3.0-5.5 years, N = 44) were assigned to play one game and watch a recording of an experimenter playing the other game. Learning was assessed during pretest and posttest using screenshots from the game. Transfer was assessed using modified screenshots (near) and real-life objects (far). Familiarity was assessed by asking children to identify the television characters and program. Findings indicate that the effectiveness of the games varied by age and condition: Younger children learned from the quantity game, but only when they watched (rather than played) the game. They did not transfer this information in either condition. Conversely, older children learned from the growth game regardless of whether they played or watched. However, older children only demonstrated far transfer if they watched (rather than played) the growth game. Thus preschoolers may benefit more by watching a video than by playing a game if the game is cognitively demanding, perhaps because making decisions while playing the game increases cognitive load. Character familiarity did not predict learning, perhaps because there was little overlap between the lessons presented in the television program and game. Findings from the current study highlight the need for more research into educational games and applications designed for preschoolers in order to establish whether, how, and for whom screen media can be educationally valuable.

The centromere is a functional chromosome domain that is essential for faithful chromosome segregation during cell division and that can be reliably identified by the presence of the centromere-specific histone H3 variant CenH3. In monocentric chromosomes, the centromere is characterized by a single CenH3-containing region within a morphologically distinct primary constriction. This region usually spans up to a few Mbp composed mainly of centromere-specific satellite DNA common to all chromosomes of a given species. In holocentric chromosomes, there is no primary constriction; the centromere is composed of many CenH3 loci distributed along the entire length of a chromosome. Using correlative fluorescence light microscopy and high-resolution electron microscopy, we show that pea (Pisum sativum) chromosomes exhibit remarkably long primary constrictions that contain 3-5 explicit CenH3-containing regions, a novelty in centromere organization. In addition, we estimate that the size of the chromosome segment delimited by two outermost domains varies between 69 Mbp and 107 Mbp, several factors larger than any known centromere length. These domains are almost entirely composed of repetitive DNA sequences belonging to 13 distinct families of satellite DNA and one family of centromeric retrotransposons, all of which are unevenly distributed among pea chromosomes. We present the centromeres of Pisum as novel "meta-polycentric" functional domains. Our results demonstrate that the organization and DNA composition of functional centromere domains can be far more complex than previously thought, do not require single repetitive elements, and do not require single centromere domains in order to segregate properly. Based on these findings, we propose Pisum as a useful model for investigation of centromere architecture and the still poorly understood role of repetitive DNA in centromere evolution, determination, and function.