Simulating three dimensional self-assembly of shape modified particles using magnetic dipolar forces

The feasibility of 3D self-assembly of milli-magnetic particles that interact via magnetic dipolar forces is investigated. Typically magnetic particles, such as isotropic spheres, self-organize in stable 2D configurations. By modifying the shape of the particles, 3D self-assembly may be enabled. The design of the particles and the experimental setup are presented. The magnetic configurations of simple particle arrangements are obtained via energy minimization in simulations. The simulations show that a 3D configuration can become energetically favourable over 2D configurations, if the shape of the particle is modified

Impression Management and the Biasing of Executive Pay Benchmarks: A Dynamic Analysis

We study the selection of peers into compensation peer groups reported by U.S. corporations. Securities and Exchange Commission (SEC) regulation requires firms to report these peer groups which are used by investors and shareholders to benchmark the compensation of CEOs. Building on a novel, dynamic analysis of more than 1,400 compensation peer groups since 2006, this paper presents new evidence that compensation peer groups are biased upwards relative to neutrally chosen “natural” peer groups. This upward bias is masked by several factors including normative selection on other criteria than compensation and the strong negative relationship between bias and the percentile at the named peer group at which the CEO is compensated. We find that adjustments to compensation peer groups are often better explained as bias-maintaining impression management than as structural adjustments to align peer groups more closely with the normative principles for peer group selection. We also find that peer group bias cannot generally be explained away as a reward for CEO talent. Our research suggests that although the SEC regulation was intended to minimize rent extraction, it has given firms a tool to manage impressions of shareholders and justify excessive pay

Trader-supplier Coordination in the Agrifood Supply Chains in Northern Ethiopia

There exists a huge agrifood potential in Ethiopia. However, the country's agrifood supply chains are underdeveloped to deliver quality supply to traders and supplement household livelihoods from the sector. The key factors that determine the proper functioning of supplier-trader chains were not rigorously investigated, at least in the case study area. This paper aims at examining the key determinants in choosing vertical coordination for agrifood products in Tigray, Northern Ethiopia. Structured questionnaires were administered to 247 traders in 10 towns in Tigray. Probit model was employed to identify the key determinants of vertical coordination. Model results show that market information, product characteristics, firm characteristics, and product quality were found significant factors in determining the adoption of vertical coordination. An interesting finding is that traders tend to vertically coordinate so as to get credit from suppliers. Based on our findings we suggest that strengthening quality assurance and contract enforcement institutions appears to be an important intervention area to improve the agrifood chain in the study area. Moreover, providing financial support to encourage the private sector to operate in agro-processing is among the efforts that need to be focused so that it facilitates the rural development process in the region.vertical coordination, trader, supplier, agrifood, supply chain, Probit Model, Agribusiness,

Contingent valuation analysis of rural households’ willingness to pay for frankincense forest conservation

Frankincense from Boswellia papyrifera forest (BPF) is a traded non timber forest product (NTFP) used in pharmaceutical, food, cosmetic and chemical industries. However, the resource in northeastern Africa is under continuous degradation and requires conservation measures. Data from a discrete choice contingent valuation study are used to assess the factors influencing rural households’ willingness to pay (WTP) and willingness to contribute labor (WTCL) for BPF conservation in Ethiopia. The standard probit, bivariate probit and interval data models were used for modeling respondents’ WTP and WTCL. We found household income as the most important factor affecting WTP whereas number of household labor is the most important factor affecting WTCL. Mean lower bound annual WTP of US$ 4.68 and WTCL of 7.03 days per household were estimated. This study indicated that despite Ethiopia is a low income country, people are willing to contribute for conservation of the resource.Willingness to pay, Boswellia papyrifera, Conservation, Contingent valuation, Resource /Energy Economics and Policy,

Blood manufacturing methods affect red blood cell product characteristics and immunomodulatory activity

Transfusion of red cell concentrates (RCCs) is associated with increased risk of adverse outcomes that may be affected by different blood manufacturing methods and the presence of extracellular vesicles (EVs). We investigated the effect of different manufacturing methods on hemolysis, residual cells, cell-derived EVs, and immunomodulatory effects on monocyte activity. Thirty-two RCC units produced using whole blood filtration (WBF), red cell filtration (RCF), apheresis-derived (AD), and whole blood-derived (WBD) methods were examined (n = 8 per method). Residual platelet and white blood cells (WBCs) and the concentration, cell of origin, and characterization of EVs in RCC supernatants were assessed in fresh and stored supernatants. Immunomodulatory activity of RCC supernatants was assessed by quantifying monocyte cytokine production capacity in an in vitro transfusion model. RCF units yielded the lowest number of platelet and WBC-derived EVs, whereas the highest number of platelet EVs was in AD (day 5) and in WBD (day 42). The number of small EVs (<200 nm) was greater than large EVs (≥200 nm) in all tested supernatants, and the highest level of small EVs were in AD units. Immunomodulatory activity was mixed, with evidence of both inflammatory and immunosuppressive effects. Monocytes produced more inflammatory interleukin-8 after exposure to fresh WBF or expired WBD supernatants. Exposure to supernatants from AD and WBD RCC suppressed monocyte lipopolysaccharide-induced cytokine production. Manufacturing methods significantly affect RCC unit EV characteristics and are associated with an immunomodulatory effect of RCC supernatants, which may affect the quality and safety of RCCs

Strategic Debt: Evidence from Bertrand and Cournot Competition

We investigate how competitive behavior affects the capital structure of a firm. Theory predicts that the impact of different types of output market uncertainty (in particular, unanticipated shocks in demand and costs) on a firm’s leverage depends on the type of competition in an industry. We test these predictions in a sample of U.S. manufacturing firms by classifying firms into Cournot competition (strategic substitutes), and Bertrand competition (strategic complements). We show that demand uncertainty is positively related to leverage for firms in both the Cournot and the Bertrand sample. Cost uncertainty has a significantly positive impact on the leverage of Cournot firms, but plays a negligible role for Bertrand firms. Our results support the strategic use of debt and highlight the role of firms’ competitive behavior in the product market in their capital structure decisions

Shining new light on mammalian diving physiology using wearable near-infrared spectroscopy

Investigation of marine mammal dive-by-dive blood distribution and oxygenation has been limited by a lack of non-invasive technology for use in freely diving animals. Here, we developed a non-invasive near-infrared spectroscopy (NIRS) device to measure relative changes in blood volume and haemoglobin oxygenation continuously in the blubber and brain of voluntarily diving harbour seals. Our results show that seals routinely exhibit preparatory peripheral vasoconstriction accompanied by increased cerebral blood volume approximately 15 s before submersion. These anticipatory adjustments confirm that blood redistribution in seals is under some degree of cognitive control that precedes the mammalian dive response. Seals also routinely increase cerebral oxygenation at a consistent time during each dive, despite a lack of access to ambient air. We suggest that this frequent and reproducible reoxygenation pattern, without access to ambient air, is underpinned by previously unrecognised changes in cerebral drainage. The ability to track blood volume and oxygenation in different tissues using NIRS will facilitate a more accurate understanding of physiological plasticity in diving animals in an increasingly disturbed and exploited environment