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This paper contributes to the study of social change by considering boundary work as a dimension of cultural change. Drawing on the computer-assisted qualitative analysis of 73 formal speeches made by Donald Trump during the 2016 electoral campaign, we argue that his political rhetoric, which led to his presidential victory, addressed the white working classes’ concern with their declining position in the national pecking order. He addressed their concern by raising the moral status of this group, that is, by 1) emphatically describing them as hard working Americans who are victims of globalization; 2) voicing their concerns about ‘people above’ (professionals, the rich, and politicians); 3) drawing strong moral boundaries toward undocumented immigrants, refugees and Muslims; 4) presenting African American and (legal) Hispanic Americans as workers who also deserve jobs; 5) stressing the role of working class men as protectors of women and LGBTQ people. This particular case study of cultural resonance provides a novel, distinctively sociological approach for capturing dynamics of social change., African and African American Studies, History of Science, Sociology

Laws can be written along a spectrum of specificity, ranging from vague standards to more detailed rules with particular examples. Behavioral and legal scholarship each present conflicting views about the optimal degree of specificity with which laws should be designed. From a behavioral standpoint, specificity is important to help people understand their goals and use their cognitive resources in a focused manner. At the same time, ambiguity in the law can even encourage good people to engage in creative interpretations of legal requirements, allowing them to justify unethical behavior, with limited awareness of the meaning of that behavior. By contrast, theories of crowding out, trust, and cooperation suggest that specificity can create resentment and lead to under-compliance and under-performance. These conflicting views about the effects of specificity serve as the background for this experimental project. This paper studies the effects of specificity on behavior in response to a directive that shares important features with the law. First, we examine the effect of specificity on compliance (following a directive) versus performance (beyond a minimum threshold). Second, we compare the controlling, limiting effects of specificity with its instructive, informative effects by comparing the interaction between specificity and monitoring with the interaction between specificity and good faith. We hypothesized that the combination of specificity and monitoring enhances the effect of specificity on compliance but harms performance and trust, whereas the combination of specificity and good faith enhances both the informative goal-setting aspects of specificity and people’s sense of commitment. The study employs an experimental design in which subjects edit a document after being exposed to detailed (vague) instructions, with (without) a reference to good faith, and with (without) monitoring (through sanctioning). The assignments were designed in such a way that people could engage in various levels of editing (both required and not required, reasonable and more than reasonable), allowing us to measure distinctly both compliance and performance. Our results suggest that when participants require information and guidance, as in the case of editing a document, specificity increases performance even beyond what is required relative to a vague standard condition.

Trust is indispensable not only for interpersonal relationships and social life, but for good quality healthcare. As manifested in the increasing violence and tension in patient-physician relationships, China has been experiencing a widespread and profound crisis of patient–physician trust. And globally, the crisis of trust is an issue that every society, either developing or developed, has to face in one way or another. Yet, in spite of some pioneering works, the subject of patient-physician trust and mistrust – a crucial matter in healthcare especially because there are numerous ethical implications – has largely been marginalized in bioethics as a global discourse. Drawing lessons as well as inspirations from China, this paper demonstrates the necessity of a trust-oriented bioethics and presents some key theoretical, methodological and philosophical elements of such a bioethics. A trust-oriented bioethics moves beyond the current dominant bioethical paradigms through putting the subject of trust and mistrust in the central agenda of the field, learning from the social sciences, and reviving indigenous moral resources. In order for global bioethics to claim its relevance to the things that truly matter in social life and healthcare, trust should be as vital as such central norms like autonomy and justice and can serve as a potent theoretical framework.

To investigate the phenomenon of patient–physician mistrust in China, a qualitative study involving 107 physicians, nurses and health officials in Guangdong Province, southern China, was conducted through semi-structured interviews and focus groups. In this paper we report the key findings of the empirical study and argue for the essential role of medical professionalism in rebuilding patient-physician trust. Health professionals are trapped in a vicious circle of mistrust. Mistrust (particularly physicians’ distrust of patients and their relatives) leads to increased levels of fear and self-protection by doctors which exacerbate difficulties in communication; in turn, this increases physician workloads, adding to a strong sense of injustice and victimization. These factors produce poorer healthcare outcomes and increasingly discontented and angry patients, escalate conflicts and disputes, and result in negative media coverage, all these ultimately contributing to even greater levels of mistrust. The vicious circle indicates not only the crisis of patient-physician relationship but the crisis of medicine as a profession and institution. Underlying the circle is the inherent conflict of interest in the healthcare system by which health professionals and hospitals have become profit-driven. This institutional conflict of interest seriously compromises the fundamental principle of medical professionalism—the primacy of patient welfare—as well as the traditional Chinese ideal of “medicine as the art of humanity”. Patient trust can be restored through rectifying this institutional conflict of interest and promoting medical professionalism via a series of recommended practical measures.

This paper describes the design and fabrication of electrically controlled paper actuators that operate based on the dimensional changes that occur in paper when the moisture absorbed on the surface of the cellulose fibers changes. These actuators are called “Hygroexpansive Electrothermal Paper Actuators” (HEPAs). The actuators are made from paper, conducting polymer, and adhesive tape. They are lightweight, inexpensive, and can be fabricated using simple printing techniques. The central element of the HEPAs is a porous conducting path (used to provide electrothermal heating) that changes the moisture content of the paper and causes actuation. This conducting path is made by embedding a conducting polymer (PEDOT:PSS) within the paper, and thus making a paper/polymer composite that retains the porosity and hydrophilicity of paper. Different types of HEPAs (straight, precurved, and creased) achieved different types of motions (e.g., bending motion, accordion type motion). A theoretical model for their behavior is proposed. These actuators have been used for the manipulation of liquids and for the fabrication of an optical shutter., Chemistry and Chemical Biology

The fields of paper microfluidics and printed electronics have developed independently, and are incompatible in many of their aspects (e.g. printed electronic thin films are not designed to tolerate the flows of liquids, and especially of water, nor are water filled-channels designed to conduct electrons). This work demonstrates monolithic integration of microfluidics and electronics on paper, by extending the use of paper microfluidics to the fabrication of electrical conductors by the wicking of aqueous conducting inks inside microfluidic channels. These conductors are unique in that they can act as wires, electrodes, and microfluidic channels at the same time. These techniques, make it possible to print both two- and three-dimensional fluidic, electrofluidic, and electrical components using simple methods, and thus to design new paper devices. This paper demonstrates the fabrication of three classes of devices: i) 3D paper “printed circuit boards”, ii) vertical-flow electroanalytical devices, and iii) foldable, all-organic paper batteries., Chemistry and Chemical Biology

Current methods of monitoring breathing require cumbersome, inconvenient, and often expensive devices; this requirement sets practical limitations on the frequency and duration of measurements. This article describes a paper-based moisture sensor that uses the hygroscopic character of paper (i.e. the ability of paper to adsorb water reversibly from the surrounding environment) to measure patterns and rate of respiration by converting the changes in humidity caused by cycles of inhalation and exhalation to electrical signals. The changing level of humidity that occurs in a cycle causes a corresponding change in the ionic conductivity of the sensor, which can be measured electrically. By combining the paper sensor with conventional electronics, data concerning respiration can be transmitted to a nearby smartphone or tablet computer for post-processing, and subsequently to a cloud server. This means of sensing provides a new, practical method of recording and analyzing patterns of breathing., Chemistry and Chemical Biology

Abating climate change is an enormous international public goods problem with a classical "free rider" structure. But it is also a global "free driver" problem because geoengineering the stratosphere with reflective particles to block incoming solar radiation is so cheap that it could essentially be undertaken unilaterally by one state perceiving itself to be in peril. This exploratory paper develops the main features of a "free driver" externality in a simple model motivated by the asymmetric consequences of type-I and type-II errors. I propose a social-choice decision architecture embodying the solution concept of a supermajority voting rule and derive its basic properties., Economics

We study optimal government debt maturity in a model where investors derive monetary services from holding riskless short-term securities. In a setting where the government is the only issuer of such riskless paper, it trades off the monetary premium associated with short-term debt against the refinancing risk implied by the need to roll over its debt more often. We then extend the model to allow private financial intermediaries to compete with the government in the provision of short-term, money-like claims. We argue that if there are negative externalities associated with private money creation, the government should tilt its issuance more towards short maturities. The idea is that the government may have a comparative advantage relative to the private sector in bearing refinancing risk and, hence, should aim to partially crowd out the private sector's use of short-term debt.

In this paper, we solve a dynamic model of households' mortgage decisions incorporating labor income, house price, inflation, and interest rate risk. Using a zero-profit condition for mortgage lenders, we solve for equilibrium mortgage rates given borrower characteristics and optimal decisions. The model quantifies the effects of adjustable versus fixed mortgage rates, loan-to-value ratios, and mortgage affordability measures on mortgage premia and default. Mortgage selection by heterogeneous borrowers helps explain the higher default rates on adjustable-rate mortgages during the recent U.S. housing downturn, and the variation in mortgage premia with the level of interest rates., Economics

In this paper, we propose an extension of the productivity decomposition method developed by Olley & Pakes (1996). This extension provides an accounting for the contributions of both firm entry and exit to aggregate productivity changes. It breaks down the contribution of surviving firms into a component accounting for changes in the firm-level distribution of productivity and another accounting for market share reallocations among those firms - following the same methodology as the one proposed by Olley & Pakes (1996). We argue that the other decompositions that break-down aggregate productivity changes into these same four components introduce some biases in the measurement of the contributions of entry and exit. We apply our proposed decomposition to the large measured increases of productivity in Slovenian manufacturing during the 1995-2000 period and contrast our results with those of other decompositions. We find that, over a 5-year period, the measurement bias associated with entry and exit is substantial, accounting for up to 10 percentage points of aggregate productivity growth. We also find that market share reallocations among surviving firms played a much more important role in driving aggregate productivity changes., Economics

A multilayered paper-based platform is used to investigate the interactions between human lung tumor cells and fibroblasts that are isolated from primary patient tumor samples., Chemistry and Chemical Biology

Despite the growth of research in universities on point-of-care (POC) diagnostics for global health, most devices never leave the laboratory. The processes that move diagnostic technology from the laboratory to the field—the processes intended to evaluate operation and performance under realistic conditions—are more complicated than they might seem. Two case studies illustrate this process: the development of a paper-based device to measure liver function, and the development of a device to identify sickle cell disease based on aqueous multiphase systems (AMPS) and differences in the densities of normal and sickled cells. Details of developing these devices provide strategies for forming partnerships, prototyping devices, designing studies, and evaluating POC diagnostics. Technical and procedural lessons drawn from these experiences may be useful to those designing diagnostic tests for developing countries, and more generally, technologies for use in resource-limited environments., Chemistry and Chemical Biology

This paper investigates whether individual venture capitalists have repeatable investment skill and to what extent their skill is impacted by the VC firm where they work. We examine a unique dataset that tracks the performance of individual venture capitalists' investments across time and as they move between firms. We find evidence of skill and exit style differences even among venture partners investing at the same VC firm at the same time. Furthermore, our estimates suggest the partner's human capital is two to five times more important than the VC firm's organizational capital in explaining performance.

Jean Tirole was awarded the 2014 Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel for his analysis of market power and regulation. This paper provides an overview of some of that work, and of his related contributions to game theory., Economics

This paper makes the case that when wishful thinking ill-founds belief, the belief depends on the desire in ways can be recapitulated at the level of perceptual experience. The relevant kinds of desires include motivations, hopes, preferences, and goals. I distinguish between two modes of dependence of belief on desire in wishful thinking: selective or inquiry-related, and responsive or evidence-related. I offers a theory of basing on which beliefs are badly-based on desires, due to patterns of dependence that can found in the relationship between experiences and desires as well. This conclusion brings us a large part of the way to the conclusion that like beliefs, experiences can be ill-founded by depending on a desire., Philosophy

This paper uses a series of experiments with commercial bank loan officers to test the effect of performance incentives on risk assessment and lending decisions. We first show that while high-powered incentives lead to greater screening effort and more profitable lending, their power is muted by both deferred compensation and the limited liability typically enjoyed by credit officers. Second, we present direct evidence that incentive contracts distort judgment and beliefs, even among trained professionals with many years of experience. Loans evaluated under more permissive incentive schemes are rated significantly less risky than the same loans evaluated under pay-for-performance.

We explore the phenomenon of co-authorship by economists who share a surname. Prior research has included at most two economist co-authors who share a surname. Ours is the first paper to have three economist co-authors who share a surname, as well as the first where such co-authors are unrelated by marriage or blood., Economics

This paper describes the fabrication of 3D soft, inflatable structures from thin, 2D tiles fabricated from elastomeric polymers. The tiles are connected using soft joints that increase the surface area available for gluing them together, and mechanically reinforce the structures to withstand the tensile forces associated with pneumatic actuation. The ability of the elastomeric polymer to withstand large deformations without failure makes it possible to explore and implement new joint designs, for example “double-taper dovetail joints,” that cannot be used with hard materials. This approach simplifies the fabrication of soft structures comprising materials with different physical properties (e.g., stiffness, electrical conductivity, optical transparency), and provides the methods required to “program” the response of these structures to mechanical (e.g., pneumatic pressurization) and other physical (e.g., electrical) stimuli. The flexibility and modularity of this approach is demonstrated in a set of soft structures that expanded or buckled into distinct, predictable shapes when inflated or deflated. These structures combine easily to form extended systems with motions dependent on the configurations of the selected components, and, when fabricated with electrically conductive tiles, electronic circuits with pneumatically active elements. This approach to the fabrication of hollow, 3D structures provides routes to new soft actuators., Chemistry and Chemical Biology

This paper demonstrates the enrichment of reticulocytes by centrifuging whole blood through aqueous multiphase systems (AMPSs)—immiscible phases of solutions of polymers that form step-gradients in density. The interfaces of an AMPS concentrate cells; this concentration facilitates the extraction of blood enriched for reticulocytes. AMPS enrich reticulocytes from blood from both healthy and hemochromatosis donors. Varying the osmolality and density of the phases of AMPS provides different levels of enrichment and yield of reticulocytes. A maximum enrichment of reticulocytemia of 64 ± 3% was obtained from donors with hemochromatosis. When used on peripheral blood from normal donors, AMPS can provide a higher yield of enriched reticulocytes and a higher proportion of reticulocytes expressing CD71 than differential centrifugation followed by centrifugation over Percoll. Blood enriched for reticulocytes by AMPS could be useful for research on malaria. Several species of malaria parasites show a preference to invade young erythrocytes and reticulocytes; this preference complicates in vitro cultivation of these species in human blood. Plasmodium knowlesi malaria parasites invade normal human blood enriched for reticulocytes by AMPSs at a rate 2.2 times greater (P < 0.01) than they invade unenriched blood. Parasite invasion in normal blood enriched by AMPS was 1.8 times greater (P < 0.05) than in blood enriched to a similar reticulocytemia by differential centrifugation followed by centrifugation over Percoll. The enrichment of reticulocytes that are invaded by malaria parasites demonstrates that AMPSs can provide a label-free method to enrich cells for biological research., Chemistry and Chemical Biology

The use of omniphobic “fluoroalkylated paper” as a substrate for inkjet printing of aqueous inks that are the precursors of electrically conductive patterns is described. By controlling the surface chemistry of the paper, it is possible to print high resolution, conductive patterns that remain conductive after folding and exposure to common solvents., Chemistry and Chemical Biology, Engineering and Applied Sciences, Other Research Unit

In complex, multicomponent systems, polymers often undergo phase transitions between distinct conformations. This paper reports a millimeter-scale granular model of coil-to-globule transitions: one “polymer” chain—a cylinders-on-a-string “pearl necklace”—and many spheres, all shaken on a horizontal surface. It is possible to describe the behavior of this granular system by using formalisms generally used in statistical physics of polymers. Two sets of experiments allowed the observation of first- and second-order coil-to-globule transitions. The model shows that the competition between long- and short-range interactions leads to a first-order transition. Well-designed granular system represents another kind of approach to the study of polymer phase transitions and might inspire future designs of polymer-like mesoscale systems., Chemistry and Chemical Biology

Soft robots actuated by pressurization and inflation of a pneumatic network (a “pneu-net”) of small channels in elastomeric materials are appealing for their ability to produce sophisticated motions with simple controls. Although current designs of pneu-nets achieve motion with large amplitudes, they do so relatively slowly (that is, over seconds). This paper describes a new design for pneu-nets that reduces the amount of gas that must be transported for inflation of the pneu-net, and thus increases its speed of actuation. A simple actuator can bend from a linear shape to a quasi-circular shape in 50 milliseconds when pressurized at ΔP = 345 kPa. At high rates of pressurization and inflation, the path along which the actuator bends depends on this rate. When inflated fully, the channels and chambers of this new pneu-net design experience only one-tenth the change in volume of that required for a motion of equal amplitude using the previous design. This small change in volume requires comparably low levels of strain in the material at maximum amplitudes of actuation, and commensurately low rates of fatigue and failure. This actuator can operate over a million cycles without significant degradation of performance. This design for soft robotic actuators combines high rates of actuation with high reliability of the actuator, and opens new areas of application for them., Chemistry and Chemical Biology

This paper compares rates of charge transport by tunneling across junctions with the structures \(Ag^{TS}X(CH_2)_{2n}CH_3 //Ga_2O_3 /EGaIn \space\) (n=1–8 and \(X= -SCH_2-\) and \(O_2C-\)); here \(Ag^{TS}\) is template-stripped silver, and EGaIn is the eutectic alloy of gallium and indium. Its objective was to compare the tunneling decay coefficient (\(\beta\), Å\(^{−1}\)) and the injection current (\(J_0\), A cm\(^{−2}\)) of the junctions comprising SAMs of n-alkanethiolates and n-alkanoates. Replacing \(Ag^{TS}SCH_2-R\) with \(Ag^{TS}O_2C-R\) (R=alkyl chains) had no significant influence on \(J_0\) (ca. \(3\times10^3 A cm^{−2}\)) or \(\beta\) (0.75–0.79 Å\(^{−1}\))—an indication that such changes (both structural and electronic) in the \(Ag^{TS}XR\) interface do not influence the rate of charge transport. A comparison of junctions comprising oligo(phenylene)carboxylates and n-alkanoates showed, as expected, that \(\beta\) for aliphatic (0.79 Å\(^{−1}\)) and aromatic (0.60 Å\(^{−1}\)) SAMs differed significantly., Chemistry and Chemical Biology, Other Research Unit

This paper compares rates of charge transport by tunneling across junctions with the structures AgTSX(CH2)2nCH3 //Ga2O3 /EGaIn (n=1–8 and X= [BOND]SCH2[BOND] and [BOND]O2C[BOND]); here AgTS is template-stripped silver, and EGaIn is the eutectic alloy of gallium and indium. Its objective was to compare the tunneling decay coefficient (β, Å−1) and the injection current (J0, A cm−2) of the junctions comprising SAMs of n-alkanethiolates and n-alkanoates. Replacing AgTSSCH2-R with AgTSO2C-R (R=alkyl chains) had no significant influence on J0 (ca. 3×103 A cm−2) or β (0.75–0.79 Å−1)—an indication that such changes (both structural and electronic) in the AgTSXR interface do not influence the rate of charge transport. A comparison of junctions comprising oligo(phenylene)carboxylates and n-alkanoates showed, as expected, that β for aliphatic (0.79 Å−1) and aromatic (0.60 Å−1) SAMs differed significantly., Chemistry and Chemical Biology

This paper characterizes the ability of soft pneumatic actuators and robots to resist mechanical insults that would irreversibly damage or destroy hard robotic systems—systems fabricated in metals and structural polymers, and actuated mechanically—of comparable sizes. The pneumatic networks that actuate these soft machines are formed by bonding two layers of elastomeric or polymeric materials that have different moduli on application of strain by pneumatic inflation; this difference in strain between an extensible top layer and an inextensible, strain-limiting, bottom layer causes the pneumatic network to expand anisotropically. While all the soft machines described here are, to some extent, more resistant to damage by compressive forces, blunt impacts, and severe bending than most corresponding hard systems, the composition of the strain-limiting layers confers on them very different tensile and compressive strengths., Chemistry and Chemical Biology, Other Research Unit

Field observations of major earthquake fault zones show that shear deformation is often confined to principal slipping zones that may be of order 1–100 μm wide, located within a broader gouge layer of order 10–100 mm wide. This paper examines the possibility that the extreme strain localization observed may be due to the coupling of shear heating, thermal pressurization, and diffusion. In the absence of a stabilizing mechanism shear deformation in a continuum analysis will collapse to an infinitesimally thin zone. Two possible stabilizing mechanisms, studied in this paper, are rate-strengthening friction and dilatancy. For rate-strengthening friction alone, a linear stability analysis shows that uniform shear of a gouge layer is unstable for perturbations exceeding a critical wavelength. Using this critical wavelength we predict a width for the localized zone as a function of the gouge properties. Taking representative parameters for fault gouge at typical centroidal depths of crustal seismogenic zones, we predict localized zones of order 5–40 μm wide, roughly consistent with field and experimental observations. For dilatancy alone, linearized strain rate perturbations with a sufficiently large wavelength will undergo transient exponential growth before decaying back to uniform shear. The total perturbation strain accumulated during this transient strain rate localization is shown to be largely controlled by a single dimensionless parameter E, which is a measure of the dilatancy of the gouge material due to an increase in strain rate., Earth and Planetary Sciences, Engineering and Applied Sciences

Field and laboratory observations indicate that at seismic slip rates most shearing is confined to a very narrow zone, just a few tens to hundreds of microns wide, and sometimes as small as a few microns. Rice et al. (2014) analyzed the stability of uniform shear in a fluid-saturated gouge material. They considered two distinct mechanisms to limit localization to a finite thickness zone, rate-strengthening friction, and dilatancy. In this paper we use numerical simulations to extend beyond the linearized perturbation context in Rice et al. (2014), and study the behavior after the loss of stability. Neglecting dilatancy we find that straining localizes to a width that is almost independent of the gouge layer width, suggesting that the localized zone width is set by the physical properties of the gouge material. Choosing parameters thought to be representative of a crustal depth of 7 km, this predicts that deformation should be confined to a zone between 4 and 44 μm wide. Next, considering dilatancy alone we again find a localized zone thickness that is independent of gouge layer thickness. For dilatancy alone we predict localized zone thicknesses between 1 and 2 μm wide for a depth of 7 km. Finally, we study the impact of localization on the shear strength and temperature evolution of the gouge material. Strain rate localization focuses frictional heating into a narrower zone, leading to a much faster temperature rise than that predicted when localization is not accounted for. Since the dynamic weakening mechanism considered here is thermally driven, this leads to accelerated dynamic weakening., Earth and Planetary Sciences, Engineering and Applied Sciences

This paper describes adaptive composites that respond to mechanical stimuli by changing their Young's modulus. These composites are fabricated by combining a shorter layer of elastic material (e.g., latex) and a longer layer of stiffer material (e.g., polyethylene and Kevlar), and fixing them together at their ends. Tension along the layered composite increases its length, and as the strain increases, the composite changes the load-bearing layer from the elastic to the stiff material. The result is a step in the Young's modulus of the composite. The characteristics of the step (or steps) can be engineered by changing the constituent materials, the number of layers, and their geometries (e.g., sinusoidal, hierarchical, two-dimensional web-like, rod-coil, embedded, and ring structures). For composites with more than two steps in modulus, the materials within the composites can be layered in a hierarchical structure to fit within a smaller volume, without sacrificing performance. These composites can also be used to make structures with tunable, stepped compressive moduli. An adaptation of these principles can generate an electronic sensor that can monitor the applied compressive strain. Increasing or decreasing the strain closes or opens a circuit and reversibly activates a light-emitting diode., Chemistry and Chemical Biology

Over the last decade the World Management Survey (WMS) has collected firm-level management practices data across multiple sectors and countries. We developed the survey to try to explain the large and persistent TFP differences across firms and countries. This review paper discusses what has been learned empirically and theoretically from the WMS and other recent work on management practices. Our preliminary results suggest that about a quarter of cross-country and within-country TFP gaps can be accounted for by management practices. Management seems to matter both qualitatively and quantitatively. Competition, governance, human capital, and informational frictions help account for the variation in management.

In vitro models of ischemia have not historically recapitulated the cellular interactions and gradients of molecules that occur in a 3D tissue. This work demonstrates a paper-based 3D culture system that mimics some of the interactions that occur among populations of cells in the heart during ischemia. Multiple layers of paper containing cells, suspended in hydrogels, are stacked to form a layered 3D model of a tissue. Mass transport of oxygen and glucose into this 3D system can be modulated to induce an ischemic environment in the bottom layers of the stack. This ischemic stress induces cardiomyocytes at the bottom of the stack to secrete chemokines which subsequently trigger fibroblasts residing in adjacent layers to migrate toward the ischemic region. This work demonstrates the usefulness of patterned, stacked paper for performing in vitro mechanistic studies of cellular motility and viability within a model of the laminar ventricle tissue of the heart., Chemistry and Chemical Biology, Engineering and Applied Sciences, Other Research Unit

Reaching for yield—the propensity to buy riskier assets in order to achieve higher yields—is believed to be an important factor contributing to the credit cycle. This paper analyses this phenomenon in the corporate bond market. Specifically, we show evidence for reaching for yield among insurance companies, the largest institutional holders of corporate bonds. Insurance companies have capital requirements tied to the credit ratings of their investments. Conditional on ratings, insurance portfolios are systematically biased toward higher yield, higher CDS bonds. This behavior appears to be related to the business cycle, being most pronounced during economic expansions. It is also more pronounced for the insurance firms for which regulatory capital requirements are more binding. The results hold both at issuance and for trading in the secondary market and are robust to a series of bond and issuer controls, including issuer fixed effects as well as liquidity and duration. Comparison of the ex-post performance of bonds acquired by insurance companies does not show outperformance but higher volatility of realized returns.

This paper describes a method for determining the density of contact trace objects with magnetic levitation (MagLev). MagLev measurements accurately determine the density (±0.0002 g/cm3) of a diamagnetic object and are compatible with objects that are nonuniform in shape and size. The MagLev device (composed of two permanent magnets with like poles facing) and the method described provide a means of accurately determining the density of trace objects. This method is inexpensive, rapid, and verifiable and provides numerical values—independent of the specific apparatus or analyst—that correspond to the absolute density of the sample that may be entered into a searchable database. We discuss the feasibility of MagLev as a possible means of characterizing forensic-related evidence and demonstrate the ability of MagLev to (i) determine the density of samples of glitter and gunpowder, (ii) separate glitter particles of different densities, and (iii) determine the density of a glitter sample that was removed from a complex sample matrix., Chemistry and Chemical Biology

This paper provides the first formal model of business model innovation. Our analysis focuses on sponsor-based business model innovations where a firm monetizes its product through sponsors rather than setting prices to its customer base. We analyze strategic interactions between an innovative entrant and an incumbent where the incumbent may imitate the entrant's business model innovation once it is revealed. The results suggest that an entrant needs to strategically choose whether to reveal its innovation by competing through the new business model or conceal it by adopting a traditional business model. We also show that the value of business model innovation may be so substantial that an incumbent may prefer to compete in a duopoly rather than to remain a monopolist.

The Army Study to Assess Risk and Resilience in Servicemembers (Army STARRS) is a multi-component epidemiological and neurobiological study of unprecedented size and complexity designed to generate actionable evidence-based recommendations to reduce U.S. Army suicides and increase basic knowledge about determinants of suicidality by carrying out coordinated component studies. A number of major logistical challenges were faced in implementing these studies. The current report presents an overview of the approaches taken to meet these challenges, with a special focus on the field procedures used to implement the component studies. As detailed in the paper, these challenges were addressed at the onset of the initiative by establishing an Executive Committee, a Data Coordination Center (the Survey Research Center [SRC] at the University of Michigan), and study-specific design and analysis teams that worked with staff on instrumentation and field procedures. SRC staff, in turn, worked with the Office of the Deputy Under Secretary of the Army (ODUSA) and local Army Points of Contact (POCs) to address logistical issues and facilitate data collection. These structures, coupled with careful fieldworker training, supervision, and piloting contributed to the major Army STARRS data collection efforts having higher response rates than previous large-scale studies of comparable military samples., Psychology

This paper describes the modular magnetic assembly of reconfigurable, pneumatically actuated robots composed of soft and hard components and materials. The soft components of these hybrid robots are actuators fabricated from silicone elastomers using soft lithography,and the hard components are acrylonitrile-butadiene-styrene (ABS) structures made using three-dimensional (3D) printing. Neodymium-iron-boron (NdFeB) ring magnets are embedded in these components to make and maintain the connections between components. The reversibility of these magnetic connections allows the rapid reconfiguration of these robots using components made of different materials (soft and hard) that also have different sizes, structures, and functions; in addition, it accelerates the testing of new designs, the exploration of new capabilities, and the repair or replacement of damaged parts. This method of assembling soft actuators to build soft machines addresses some limitations associated with using soft lithography for the direct molding of complex 3D pneumatic networks. Combining the self-aligning property of magnets with pneumatic control makes it possible for a teleoperator to modify the structures and capabilities of these robots readily in response to the requirements of different tasks., Physics

For many molecular ecologists, the mantra and mission of the field of ecological genomics could be encapsulated by the phrase ‘to find the genes that matter’ (Mitchell-Olds 2001; Rockman 2012). This phrase of course refers to the early hope and current increasing success in the search for genes whose variation underlies phenotypic variation and fitness in natural populations. In the years since the modern incarnation of the field of ecological genomics, many would agree that the low-hanging fruit has, at least in principle, been plucked: we now have several elegant examples of genes whose variation influences key adaptive traits in natural populations, and these examples have revealed important insights into the architecture of adaptive variation (Hoekstra et al. 2006; Shapiro et al. 2009; Chan et al. 2010). But how well will these early examples, often involving single genes of large effect on discrete or near-discrete phenotypes, represent the dynamics of adaptive change for the totality of phenotypes in nature? Will traits exhibiting continuous rather than discrete variation in natural populations have as simple a genetic basis as these early examples suggest (Prasad et al. 2012; Rockman 2012)? Two papers in this issue (Robinson et al. 2013; Santure et al. 2013) not only suggest answers to these questions but also provide useful extensions of statistical approaches for ecological geneticists to study the genetics of continuous variation in nature. Together these papers, by the same research groups studying evolution in a natural population of Great Tits (Parus major), provide a glimpse of what we should expect as the field begins to dissect the genetic basis of what is arguably the most common type of variation in nature, and how genome-wide surveys of variation can be applied to natural populations without pedigrees., Organismic and Evolutionary Biology

The fabrication and properties of “fluoroalkylated paper” (“\(R^F\) paper”) by vapor-phase silanization of paper with fluoroalkyl trichlorosilanes is reported. \(R^F\) paper is both hydrophobic and oleophobic: it repels water \((θ_{app}^{H2O} > 140^{\circ})\), organic liquids with surface tensions as low as \(28 \space mN \space m^{-1}\), aqueous solutions containing ionic and non-ionic surfactants, and complex liquids such as blood (which contains salts, surfactants, and biological material such as cells, proteins, and lipids). The propensity of the paper to resist wetting by liquids with a wide range of surface tensions correlates with the length and degree of fluorination of the organosilane (with a few exceptions in the case of methyl trichlorosilane-treated paper), and with the roughness of the paper. \(R^F\) paper maintains the high permeability to gases and mechanical flexibility of the untreated paper, and can be folded into functional shapes (e.g., microtiter plates and liquid-filled gas sensors). When impregnated with a perfluorinated oil, \(R^F\) paper forms a “slippery” surface (paper slippery liquid-infused porous surface, or “paper SLIPS“) capable of repelling liquids with surface tensions as low as \(15 \space mN \space m^{-1}\). The foldability of the paper SLIPS allows the fabrication of channels and flow switches to guide the transport of liquid droplets., Chemistry and Chemical Biology, Other Research Unit

We study resilient functions and exposure-resilient functions in the low-entropy regime. A resilient function (a.k.a. deterministic extractor for oblivious bit-fixing sources) maps any distribution on n -bit strings in which k bits are uniformly random and the rest are fixed into an output distribution that is close to uniform. With exposure-resilient functions, all the input bits are random, but we ask that the output be close to uniform conditioned on any subset of n - k input bits. In this paper, we focus on the case that k is sublogarithmic in n. We simplify and improve an explicit construction of resilient functions for k sublogarithmic in n due to Kamp and Zuckerman (SICOMP 2006), achieving error exponentially small in k rather than polynomially small in k. Our main result is that when k is sublogarithmic in n, the short output length of this construction (O(log k) output bits) is optimal for extractors computable by a large class of space-bounded streaming algorithms. Next, we show that a random function is a resilient function with high probability if and only if k is superlogarithmic in n, suggesting that our main result may apply more generally. In contrast, we show that a random function is a static (resp. adaptive) exposure-resilient function with high probability even if k is as small as a constant (resp. loglog n). No explicit exposure-resilient functions achieving these parameters are known., Engineering and Applied Sciences, Mathematics

The Army Study to Assess Risk and Resilience in Servicemembers (Army STARRS) is a multi-component epidemiological and neurobiological study designed to generate actionable recommendations to reduce U.S. Army suicides and increase knowledge about determinants of suicidality. Three Army STARRS component studies are large-scale surveys: one of new soldiers prior to beginning Basic Combat Training (BCT; n=50,765 completed self-administered questionnaires); another of other soldiers exclusive of those in BCT (n=35,372); and a third of three Brigade Combat Teams about to deploy to Afghanistan who are being followed multiple times after returning from deployment (n= 9,421). Although the response rates in these surveys are quite good (72.0-90.8%), questions can be raised about sample biases in estimating prevalence of mental disorders and suicidality, the main outcomes of the surveys based on evidence that people in the general population with mental disorders are under-represented in community surveys. This paper presents the results of analyses designed to determine whether such bias exists in the Army STARRS surveys and, if so, to develop weights to correct for these biases. Data are also presented on sample inefficiencies introduced by weighting and sample clustering and on analyses of the trade-off between bias and efficiency in weight trimming., Psychology

How do rankings affect demand? This paper investigates the impact of college rankings, and the visibility of those rankings, on students' application decisions. Using natural experiments from U.S. News and World Report College Rankings, we present two main findings. First, we identify a causal impact of rankings on application decisions. When explicit rankings of colleges are published in U.S. News, a one-rank improvement leads to a 1-percentage-point increase in the number of applications to that college. Second, we show that the response to the information represented in rankings depends on the way in which that information is presented. Rankings have no effect on application decisions when colleges are listed alphabetically, even when readers are provided data on college quality and the methodology used to calculate rankings. This finding provides evidence that the salience of information is a central determinant of a firm's demand function, even for purchases as large as college attendance.

Most taxonomists agree on the need to adapt current classifications to recognize monophyletic units. However, delineations between higher taxonomic units can be based on the relative ages of different lineages and/or the level of morphological differentiation. In this paper, we address these issues in considering the species-rich Polyommatus section, a group of butterflies whose taxonomy has been highly controversial. We propose a taxonomy-friendly, flexible temporal scheme for higher-level classification. Using molecular data from nine markers (6666 bp) for 104 representatives of the Polyommatus section, representing all but two of the 81 described genera/subgenera and five outgroups, we obtained a complete and well resolved phylogeny for this clade. We use this to revise the systematics of the Polyommatus blues, and to define criteria that best accommodate the described genera within a phylogenetic framework. First, we normalize the concept of section (Polyommatus) and propose the use of subtribe (Polyommatina) instead. To preserve taxonomic stability and traditionally recognized taxa, we designate an age interval (4–5 Myr) instead of a fixed minimum age to define genera. The application of these criteria results in the retention of 31 genera of the 81 formally described generic names, and necessitates the description of one new genus (Rueckbeilia gen. nov.). We note that while classifications should be based on phylogenetic data, applying a rigid universal scheme is rarely feasible. Ideally, taxon age limits should be applied according to the particularities and pre-existing taxonomy of each group. We demonstrate that the concept of a morphological gap may be misleading at the genus level and can produce polyphyletic genera, and we propose that recognition of the existence of cryptic genera may be useful in taxonomy., Organismic and Evolutionary Biology

This paper examines changes in disaster response and relief efforts and recent web-based geospatial technological developments through an evaluation of the experiences of the Center for Geographic Analysis, Harvard University, of the Sichuan (2008) and Haiti (2010) earthquake responses. This paper outlines how conventional GIS (geographic information systems) disaster responses by governmental agencies and relief response organisations and the means for geospatial data-sharing have been transformed into a more dynamic, more transparent, and decentralised form with a wide participation. It begins by reviewing briefly at historical changes in the employment of geospatial technologies in major devastating disasters, including the Sichuan and Haiti earthquakes (case studies for our geospatial portal project). It goes on to assess changes in the available dataset type and in geospatial disaster responders, as well as the impact of geospatial technological changes on disaster relief effort. Finally, the paper discusses lessons learned from recent responses and offers some thoughts for future development., Other Research Unit

A “property clause” is a dedicated text in the written basic law of a constitutional-democratic state, addressing the question of the security of asset-holdings (and of their values to their owners) against impairment by action or allowance of the state. The clause provides a defensive guarantee against such impairments, in the form of a trumping right of every person to be protected – perhaps not absolutely and unconditionally, but not negligibly, either – against state-engineered losses in lawfully established asset-holdings or asset-values. How should someone writing a constitution for an expectantly “social liberal” state regime think about the question of a property clause? Without suggesting that there can be any one-size-fits-all sort of answer to the question of including such a clause or not, this paper confines itself to doubting sharply one sort of a reason our constitution-writers might consider for including one – namely, that a liberal constitutional bill of rights ought to contain clauses covering all classes of interests of persons that qualify in liberalism as basic rights and freedoms and the interest distinctively protected by a property clause does so qualify – and suggesting some pros and cons regarding a quite different sort of reason for inclusion that the writers will also undoubtedly ponder – namely, that the clause will serve to keep lawmakers and constitutional adjudicators properly attuned to a national foundational commitment to a system of political economy in which markets play a key role. This essay, prepared as an after-dinner talk for the Conference on Constitutional Revolutions and Counter-Revolutions held at the New School for Social Research, May 5-7, 2011, is a companion to my “Liberal Constitutionalism, Property Rights, and the Assault on Poverty,” Stellenbosch Law Review (2012) (forthcoming), which treats more expansively some points made summarily here. A version of this essay will appear in Constellations 12 (2012).

Identification of trade-offs among physiological and morphological traits and their use in cost-benefit models and ecological or evolutionary optimization arguments have been hallmarks of ecological analysis for at least 50 years. Carnivorous plants are model systems for studying a wide range of ecophysiological and ecological processes and the application of a cost-benefit model for the evolution of carnivory by plants has provided many novel insights into trait-based cost-benefit models. Central to the cost-benefit model for the evolution of botanical carnivory is the relationship between nutrients and photosynthesis; of primary interest is how carnivorous plants efficiently obtain scarce nutrients that are supplied primarily in organic form as prey, digest and mineralize them so that they can be readily used, and allocate them to immediate versus future needs. Most carnivorous plants are terrestrial – they are rooted in sandy or peaty wetland soils – and most studies of cost-benefit trade-offs in carnivorous plants are based on terrestrial carnivorous plants. However approximately 10% of carnivorous plants are unrooted aquatic plants. In this Forum paper, we ask whether the cost-benefit model applies equally well to aquatic carnivorous plants and what general insights into trade-off models are gained by this comparison. Nutrient limitation is more pronounced in terrestrial carnivorous plants, which also have much lower growth rates and much higher ratio of dark respiration to photosynthetic rates than aquatic carnivorous plants. Phylogenetic constraints on ecophysiological trade-offs among carnivorous plants remain unexplored. Despite differences in detail, the general cost-benefit framework continues to be of great utility in understanding the evolutionary ecology of carnivorous plants. We provide a research agenda that if implemented would further our understanding of ecophysiological trade-offs in carnivorous plants and also would provide broader insights into similarities and differences between aquatic and terrestrial plants of all types., Organismic and Evolutionary Biology, Other Research Unit

This paper reviews recent efforts to realize a high-efficiency memory for optical pulses using slow and stored light based on electromagnetically induced transparency (EIT) in ensembles of warm atoms in vapor cells. After a brief summary of basic continuous-wave and dynamic EIT properties, studies using weak classical signal pulses in optically dense coherent media are discussed, including optimization strategies for stored light efficiency and pulse-shape control, and modification of EIT and slow/stored light spectral properties due to atomic motion. Quantum memory demonstrations using both single photons and pulses of squeezed light are then reviewed. Finally a brief comparison with other approaches is presented., Physics

Purpose Little is known about communication with patients suffering from hematologic malignancies, many of whom are seen by subspecialists in consultation at tertiary-care centers. These subspecialized consultations might provide the best examples of optimal physician–patient communication behaviors, given that these consultations tend to be lengthy, to occur between individuals who have not met before and may have no intention of an ongoing relationship, and which have a goal of providing treatment recommendations. The aim of this paper is to describe and quantify the content of the subspecialty consultation in regards to exchanging information and identify patient and provider characteristics associated with discussion elements. Methods Audio-recorded consultations between 236 patients and 40 hematologists were coded for recommended communication practices. Multilevel models for dichotomous outcomes were created to test associations between patient, physician and consultation characteristics and key discussion elements. Results Discussions about the purpose of the visit and patient’s knowledge about their disease were common. Other elements such as patient’s preference for his/her role in decision-making, preferences for information, or understanding of presented information were less common. Treatment recommendations were provided in 97% of the consultations and unambiguous presentations of prognosis occurred in 81% of the consultations. Unambiguous presentations of prognosis were associated with non-White patient race, lower educational status, greater number of questions asked, and specific physician provider. Conclusion Although some communication behaviors occur in most consultations, others are much less common and could help tailor the amount and type of information discussed. Approximately half of the patients are told unambiguous prognostic estimates for mortality or cure.

In response to Arroyo, I explain my position on the concept of “natural goodness” and how my use of that concept compares to that of Geach and Foot. An Aristotelian or functional notion of goodness provides the material for Kantian endorsement in a theory of value that avoids a metaphysical commitment to intrinsic values. In response to Cummiskey, I review reasons for thinking Kantianism and consequentialism incompatible, especially those objections to aggregation that arise from the notion of the natural good previously described. In response to Moland, I explain why I think Hegelian worries about the supposed emptiness of the Kantian self do not apply to my account. And in response to both Moland and Bird-Pollan, I argue that, contrary to the view of some Hegelians, the intersubjective normativity of reason is not something developed through actual social relations; rather, it is something essential to an individual's relations with himself or herself. I want to begin by thanking Christopher Arroyo, David Cummiskey, Lydia Moland, and Stefan Bird-Pollan for their interesting and provocative comments in this symposium. There's more in their papers than I can possibly respond to in a reasonable space, so I'm just going to pick and choose. “The Origin of the Good and Our Animal Nature” spells out some of my current thinking on the good, so a summary of that paper will put me in a position to begin by addressing some of Arroyo's and Cummiskey's points., Philosophy

[1] Opportunity has been traversing the Meridiani plains since 25 January 2004 (sol 1), acquiring numerous observations of the atmosphere, soils, and rocks. This paper provides an overview of key discoveries between sols 511 and 2300, complementing earlier papers covering results from the initial phases of the mission. Key new results include (1) atmospheric argon measurements that demonstrate the importance of atmospheric transport to and from the winter carbon dioxide polar ice caps; (2) observations showing that aeolian ripples covering the plains were generated by easterly winds during an epoch with enhanced Hadley cell circulation; (3) the discovery and characterization of cobbles and boulders that include iron and stony-iron meteorites and Martian impact ejecta; (4) measurements of wall rock strata within Erebus and Victoria craters that provide compelling evidence of formation by aeolian sand deposition, with local reworking within ephemeral lakes; (5) determination that the stratigraphy exposed in the walls of Victoria and Endurance craters show an enrichment of chlorine and depletion of magnesium and sulfur with increasing depth. This result implies that regional-scale aqueous alteration took place before formation of these craters. Most recently, Opportunity has been traversing toward the ancient Endeavour crater. Orbital data show that clay minerals are exposed on its rim. Hydrated sulfate minerals are exposed in plains rocks adjacent to the rim, unlike the surfaces of plains outcrops observed thus far by Opportunity. With continued mechanical health, Opportunity will reach terrains on and around Endeavour's rim that will be markedly different from anything examined to date., Earth and Planetary Sciences