cssi/SciSciGPT-SciSciNet huggingface dataset:
One‐Dimensional Zinc Selenophosphates: A2ZnP2Se6 (A = K, Rb, Cs)

The new compounds A2ZnP2Se6 (A = K, Rb, Cs) were synthesized via molten salt flux syntheses. The crystals feature one-dimensional 1/∞[ZnP2Se6]2– chains charge balanced by alkali metal ions between the chains. K2ZnP2Se6 crystallizes in the monoclinic space group P21/c; cell parameters a = 12.537(3) A, b = 7.2742(14) A, c = 14.164(3) A, β = 109.63(3)°, Z = 4, and V = 1216.7(4) A3. Rb2ZnP2Se6 and Cs2ZnP2Se6 are isotypic, crystallizing in the triclinic space group P. Rb2ZnP2Se6 has cell parameters of a = 7.4944(15) A, b = 7.6013(15) A, c = 12.729(3) A, α = 96.57(3)°, β = 105.52(3)°, γ = 110.54(3)°, Z = 2, and V = 636.6(2) A3. Cs2ZnP2Se6 has cell parameters of a = 7.6543(6) A, b = 7.7006(6) A, c = 12.7373(11) A, α = 97.007(7)°, β = 104.335(7)°, γ = 109.241(6)°, Z = 2, and V = 669.54(10) A3.
Slow slip hidden in the noise: the intermittence of tectonic release

Referred to as slow slip events, the transient aseismic slip that occurs along plate boundaries can be indirectly characterized through colocated seismicity, such as tectonic tremor and low-frequency earthquakes (LFEs). Using the timing of cataloged LFE and tremor activity in Guerrero, Mexico and northern Cascadia, I decompose the inter-aseismic GPS displacement, defined as the surface deformation between previously detected slow slip events, into separate regimes of tectonic loading and release. In such a way, previously undetected slow slip events that produce less than a millimeter of surface deformation are extracted from the geodetic noise. These new observations demonstrate that the inter-aseismic period is not quiescent and that slow slip occurs much more often than previously thought. This suggests that the plate interface where slow slip and tremor occur is in fact strongly coupled and that slow aseismic release occurs over a wide spectrum of time scales.
Mentoring partnerships in science education

AbstractThe authors use an action research (AR) approach in a collegiate studio physics class to investigate the power of partnerships via conferences as they relate to issues of establishing a student/mentor rapport, empowering students to reduce inequity, and the successes and barriers to hearing students’ voices. The graduate teaching assistant (TA, Author 1) conducted one-on-one conferences with 29 students, elicited student opinions about the progress of the course, and talked with faculty, TAs, and an undergraduate supplemental instructor for other sections of the course. At the end of the semester, the students reported increased knowledge of the TA as a person and as an instructor, and vice versa. Sixty-five percent of students reported no interest in changing circumstances to make it easier to talk about personal concerns with the TA. College students reluctantly voiced their opinions about the course, possibly due to the power structure of the classroom. Other TAs in the department expressed mos...
THE ACOUSTIC AND INSTABILITY WAVES OF JETS CONFINED INSIDE AN ACOUSTICALLY LINED RECTANGULAR DUCT

An analysis of linear wave modes associated with supersonic jets confined inside an acoustically lined rectangular duct is presented. Mathematical formulations are given for the vortex-sheet model and continuous mean flow model of the jet flow profiles. Detailed dispersion relations of these waves in a two-dimensional confined jet as well as an unconfined free jet are computed. Effects of the confining duct and the liners on the jet instability and acoustic waves are studied numerically. It is found that the effect of the liners is to attenuate waves that have supersonic phase velocities relative to the ambient flow. Numerical results also show that the growth rates of the instability waves could be reduced significantly by the use of liners. In addition, it is found that the upstream propagating neutral waves of an unconfined jet could become attenuated when the jet is confined.
A Real Estate Boom with Chinese Characteristics

Abstract Chinese housing prices rose by over 10 percent per year in real terms between 2003 and 2014 and are now between two and ten times higher than the construction cost of apartments. At the sa...
Tactual displays for wearable computing

This paper provides a general overview of tactual displays (i.e., devices that communicate to a user through the sense of touch) and issues concerning the development of such displays for wearable computing. A wearable tactile directional display is presented. It takes advantage of a sensory phenomenon called "sensory saltation" and simulates directional lines and simple geometric patterns dynamically. Initial results indicate that this information is intuitive and easy to interpret even for first-time users, and interpretations are highly consistent among observers. Several applications of this tactile directional display for wearable computing are proposed.
Coevolution of Cooperation and Partner Rewiring Range in Spatial Social Networks

In recent years, there has been growing interest in the study of coevolutionary games on networks. Despite much progress, little attention has been paid to spatially embedded networks, where the underlying geographic distance, rather than the graph distance, is an important and relevant aspect of the partner rewiring process. It thus remains largely unclear how individual partner rewiring range preference, local vs. global, emerges and affects cooperation. Here we explicitly address this issue using a coevolutionary model of cooperation and partner rewiring range preference in spatially embedded social networks. In contrast to local rewiring, global rewiring has no distance restriction but incurs a one-time cost upon establishing any long range link. We find that under a wide range of model parameters, global partner switching preference can coevolve with cooperation. Moreover, the resulting partner network is highly degree-heterogeneous with small average shortest path length while maintaining high clustering, thereby possessing small-world properties. We also discover an optimum availability of reputation information for the emergence of global cooperators, who form distant partnerships at a cost to themselves. From the coevolutionary perspective, our work may help explain the ubiquity of small-world topologies arising alongside cooperation in the real world.
The unitary elasticity property in a monocentric city with negative exponential population density

Abstract The central prediction of the monocentric city model is that real estate prices, density of development, population density, and land rent decline with the distance from urban center. The spatial pattern follows a negative exponential under the conditions derived by Brueckner (1982) and McDonald and Kim (1987). Research has demonstrated that these exponential density gradients have flattened over time due to rising income and falling transportation costs. This paper identifies a heretofore unknown property in a monocentric city with negative exponential population density, the “unitary elasticity property (UEP).” If a city is characterized by a constant density gradient, even if the slope of that gradient is changing over time, the sum of the elasticity of central density and the elasticity of land area with respect to population change will be approximately equal to unity. When this new prediction is tested, it fits US cities fairly well. Further analysis demonstrates that topographic barriers and age of housing stock are the key factors explaining the deviation from the UEP.
Elliptic complexes of first-order cone operators: ideal boundary conditions

The purpose of this paper is to provide a detailed description of the spaces that can be specified as L2 domains for the operators of a first order elliptic complex on a compact manifold with conical singularities. This entails an analysis of the nature of the minimal domain and of a complementary space in the maximal domain of each of the operators. The key technical result is the nondegeneracy of a certain pairing of cohomology classes associated with the indicial complex. It is further proved that the set of choices of domains leading to Hilbert complexes in the sense of Bruning and Lesch form a variety, as well as a theorem establishing a necessary and sufficient condition for the operator in a given degree to map its maximal domain into the minimal domain of the next operator.
A merged quadrupole-calorimeter for CEPC

The luminosity ℒ of colliding beams in a storage ring such as CEPC depends strongly on l∗, the half-length of the free space centered on the intersection point (IP). l∗ is also the length from the IP to the front edges of the two near-in quadrupoles that are focusing the counter-circulating beams to the IP spot. The detector length cannot, therefore, exceed 2l∗. Since ℒ increases strongly with decreasing l∗, there is incentive for reducing l∗; but this requires the detector to be shorter than desirable. This paper proposes a method for integrating these adjacent quadrupoles into the particle detector to retain (admittedly degraded) active particle detection of those forward going particles that would otherwise be obscured by the quadrupole. A gently conical quadrupole shape is more natural for merging the quadrupole into the particle detector than is the analytically exact cylindrical shape. This is true whether or not the calorimeter is integrated. It will be the task of accelerator physicists to determine the extent to which deviation from the pure quadrupole field compromises (or improves) accelerator performance. Superficially, both the presence of strongest gradient close to the IP and largest aperture farther from the IP seem to be advantageous. A tentative design for this merged, quadrupole-calorimeter is given.
Spectral gap of scl in free products

Let $G=*_\lambda G_\lambda$ be a free product of torsion-free groups, and let $g\in[G,G]$ be any element not conjugate into a $G_\lambda$. Then scl$_G(g)\ge1/2$. This generalizes, and gives a new proof of a theorem of Duncan-Howie.
Pass-through of competitors' exchange rates to US import and producer prices

This paper shows that in theory and BLS microdata, the prices of imported goods respond to the exchange rates (ER) of the producer's foreign competitors. In contrast, standard models have no role for competitors' ERs. Excluding the effects of competitors' exchange rates typically biases upwards estimates of bilateral exchange rate pass-through because competitors' ERs and bilateral ERs are positively correlated. A multi-country version of Atkeson and Burstein's (2008) industry aggregation model is able to explain a sizable proportion of pass-through of competitors' exchange rates to import prices, and also predicts pass-through of foreign competitors' prices and pass-through of competitors' ERs to US producer prices -- both of which are supported in the data. The results suggest that pass-through will be larger for ER movements shared by a greater fraction of foreign competitor countries.
In-storage embedded accelerator for sparse pattern processing

We present a novel architecture for sparse pattern processing, using flash storage with embedded accelerators. Sparse pattern processing on large data sets is the essence of applications such as document search, natural language processing, bioinformatics, subgraph matching, machine learning, and graph processing. One slice of our prototype accelerator is capable of handling up to 1TB of data, and experiments show that it can outperform C/C++ software solutions on a 16-core system at a fraction of the power and cost; an optimized version of the accelerator can match the performance of a 48-core server.
Accelerator or Brake? Cash for Clunkers, Household Liquidity, and Aggregate Demand

We evaluate the Car Allowance Rebate System (CARS) by comparing the vehicle purchases and disposals of households with eligible “clunkers” to those of households with similar, but ineligible, vehicles. We find that CARS caused roughly 500,000 purchases during the program period and that the liquidity provided by CARS was critical for generating this large response. CARS provided less liquidity for households owning clunkers securing loans, since participation required loan repayment. The participation rate of these households was low, which we attribute to liquidity constraints and distinguish from the effects of other indebtedness, household income, and the size of the program subsidy.
Evaluation of die edge cracking in flip-chip PBGA packages

Increasing die size and large coefficient of thermal expansion (CTE) mismatch in flip-chip plastic ball grid array (FC-PBGA) packages have made die fracture a major failure mode during reliability testing. Most die fracture observed before was die backside vertical cracking, which was caused by excessive package bending and backside defects. However, due to die edge defects induced by the singulation process and the choice of underfill material, an increasing number of die cracks were found to initiate from die edge and propagate horizontally across the die. In order to improve package reliability and performance, die edge cracking has to be eliminated. An extensive finite element analysis was completed to investigate die edge cracking and find its solutions. A fracture mechanics approach was used to evaluate the effect of various package parameters on die edge initiated fracture. Strain energy release rate was found to be an effective technique for evaluating die edge initiated fracture from singulation-induced flaws. The impact of initial flaw size and a variety of package parameters was investigated. Unlike in die backside cracking, the dominant parameters causing die edge horizontal fracture are more closely related to local effects.
The effect of TARP on the propagation of real estate shocks: Evidence from geographically diversified banks

Abstract This study examines the effect of TARP on the propagation of real estate shocks via geographically diversified banks in the U.S. I find that TARP money provided for banks exposed to distressed areas (i.e., “affected” banks) was positively associated with small business loan originations in “non-distressed” areas (i.e., counties with smaller real estate shocks), mitigating the shock transmission. In addition, the bailout funds facilitated “affected” banks’ faster return to their pre-crisis level of franchise value. Overall, the marginal benefit of TARP funds seems to have been greater for “affected” TARP banks. I conclude that this policy helped “affected” banks cleanse/strengthen their balance sheets and recapitalize, which paved the way for increased lending.
Feedback can reduce the specification complexity of motor programs

We show that when it is possible to use feedback in the specification of "motor programs," the length of the descriptions of the instruction sequences for carrying out a given task can be reduced by a factor that reflects the richness of the available feedback signals. The model on which this work is based is that of a finite automaton, modified in such a way that instruction processing is akin to the way in which difference or differential equations "process" piecewise constant inputs. In terms of such "free-running" automata, we show that when feedback is available the length of the shortest description can be reduced by a factor depending on the ratio of the size of the entire state space to the size of the set of states for which feedback is locally effective.
Optimal Self-Assembly of Finite Shapes at Temperature 1 in 3D

Tile self-assembly in which tiles may bind in a non-cooperative fashion is often referred to as “temperature 1 self-assembly” or simply “non-cooperative self-assembly”. In this type of self-assembly, a tile may non-cooperatively bind to an assembly via (at least) one of its sides, unlike in cooperative self-assembly, in which some tiles may be required to bind on two or more sides. Cooperative self-assembly leads to highly non-trivial theoretical behavior but two-dimensional non-cooperative self-assembly is conjectured to be only capable of producing highly-regular shapes and patterns, which, in general, cannot be interpreted as complex computation. Remarkably, Cook et al. (Temperature 1 self-assembly: deterministic assembly in 3D and probabilistic assembly in 2D. In: Proceedings of the 22nd Annual ACM–SIAM Symposium on Discrete Algorithms 2011) showed that three-dimensional non-cooperative self-assembly is essentially as powerful as cooperative self-assembly, with respect to Turing universality and self-assembly of $$N \times N$$ squares. In this paper, we consider the non-cooperative self-assembly of just-barely 3D shapes. Working in a three-dimensional variant of Winfree’s abstract Tile Assembly Model, we show that, for an arbitrary finite, connected shape $$X \subset {\mathbb {Z}}^2$$ , there is a tile set that uniquely self-assembles at temperature 1 into a 3D representation of a scaled-up version of X with optimal program-size complexity, where the “program-size complexity”, also known as “tile complexity”, of a shape is the minimum number of tile types required to uniquely self-assemble it. Moreover, our construction is “just barely” 3D in the sense that it only places tiles in the $$z = 0$$ and $$z = 1$$ planes. Our result is essentially a just-barely 3D temperature 1 simulation of a similar 2D temperature 2 result by Soloveichik and Winfree (SIAM J Comput 36(6):1544–1569, 2007).
Adaptive and Power-Aware Resilience for Extreme-Scale Computing

With concerted efforts from researchers in hardware, software, algorithm,, resource management, HPC is moving towards extreme-scale, featuring a computing capability of exaFLOPS. As we approach the new era of computing, however, several daunting scalability challenges remain to be conquered. Delivering extreme-scale performance will require a computing platform that supports billion-way parallelism, necessitating a dramatic increase in the number of computing, storage,, networking components. At such a large scale, failure would become a norm rather than an exception, driving the system to significantly lower efficiency with unprecedented amount of power consumption. To tackle these challenges, we propose an adaptive, power-aware algorithm, referred to as Lazy Shadowing, as an efficient, scalable approach to achieve high-levels of resilience, through forward progress, in extreme-scale, failure-prone computing environments. Lazy Shadowing associates with each process a "shadow" (process) that executes at a reduced rate,, opportunistically rolls forward each shadow to catch up with its leading process during failure recovery. Compared to existing fault tolerance methods, our approach can achieve 20% energy saving with potential reduction in solution time at scale.
Total fluid pressure imbalance in the scrape-off layer of tokamak plasmas

Simulations using the fully kinetic neoclassical code XGCa (X-point included guiding- center axisymmetric) were undertaken to explore the impact of kinetic effects on scrape-off layer (SOL) physics in DIII-D H-mode plasmas. XGCa is a total-f, gyrokinetic code which self-consistently calculates the axisymmetric electrostatic potential and plasma dynamics, and includes modules for Monte Carlo neutral transport. Previously presented XGCa results showed several noteworthy features, including large variations of ion density and pressure along field lines in the SOL, experimentally relevant levels of SOL parallel ion flow (Mach number ~ 0.5), skewed ion distributions near the sheath entrance leading to subsonic flow there, and elevated sheath potentials (Churchill 2016 Nucl. Mater. Energy 1–6). In this paper, we explore in detail the question of pressure balance in the SOL, as it was observed in the simulation that there was a large deviation from a simple total pressure balance (the sum of ion and electron static pressure plus ion inertia). It will be shown that both the contributions from the ion viscosity (driven by ion temperature anisotropy) and neutral source terms can be substantial, and should be retained in the parallel momentum equation in the SOL, but still falls short of accounting for the observed fluid pressure imbalance in the XGCa simulation results.
The effect of hydrogen on the solid solution strengthening and softening of nickel

Abstract The effects of hydrogen on the plastic deformation of nickel and nickel-carbon alloys were studied using plastic deformation techniques over a wide range of strain rates at about 300 K. The emphasis of the study was on the behavior at very low strains and low strain rates. Hydrogen was introduced as a solute element by quenching from a gaseous H2 atmosphere or by testing in a gaseous H2 atmosphere. The behavior of a number of different purities of nickel with hydrogen additions was examined. The most significant impurity element seemed to be C and this element was varied over a wide composition range by annealing in different atmospheres. Both solution softening and solution strengthening was observed depending on the amount of H in solution relative to the amount of C in solution. The nature of this solution softening effect is discussed.
Power dissipation in fractal Feynman-Sierpinski AC circuits

This paper studies the concept of power dissipation in infinite graphs and fractals associated with passive linear networks consisting of non-dissipative elements. In particular, we analyze the so-called Feynman-Sierpinski ladder, a fractal AC circuit motivated by Feynman’s infinite ladder, that exhibits power dissipation and wave propagation for some frequencies. Power dissipation in this circuit is obtained as a limit of quadratic forms, and the corresponding power dissipation measure associated with harmonic potentials is constructed. The latter measure is proved to be continuous and singular with respect to an appropriate Hausdorff measure defined on the fractal dust of nodes of the network.
Optimum array filters for array data signal processing

This paper deals with the design of filters for processing data obtained from arrays of sensors used for signal measurements in a variety of applications. The objective of the filters is to optimally suppress undesired signals intercepting the array while at the same time preserve the desired signal that the array is attempting to measure. A constrained minimization problem is formulated for determining the filters coefficients and the computational requirements necessary for designing and applying the filters are kept to a minimum. When compared to the widely used delay-and-sum and Chebyshev methods, this technique is shown to have a superior frequency reject response which becomes more apparent if the array has a relatively small number of sensors.
Crowdsourced outcome determination in prediction markets

A prediction market is a useful means of aggregating information about a future event. To function, the market needs a trusted entity who will verify the true outcome in the end. Motivated by the recent introduction of decentralized prediction markets, we introduce a mechanism that allows for the outcome to be determined by the votes of a group of arbiters who may themselves hold stakes in the market. Despite the potential conflict of interest, we derive conditions under which we can incentivize arbiters to vote truthfully by using funds raised from market fees to implement a peer prediction mechanism. Finally, we investigate what parameter values could be used in a real-world implementation of our mechanism.
ISLAMIC LAW AND ELDER CARE IN THE CENTRAL ASIAN EDGEN SYSTEM

There is no uniform Islamic law of elder care. Instead, the Qur’ān and Hadith, the fundamental building blocks of Islamic law, create general obligations to support aged parents that each Islamic society must specifically produce in practice. Before Islam swept Central Asia, nomads developed an elder-care tradition that thrives to this day in the former Soviet States of Kazakhstan (population 17 million), Kyrgyzstan (5.7 million), Tajikistan (8 million), Turkmenistan (5.2 million), and Uzbekistan (30 million). In many instances, Islamic law inclines toward adopting local customs and traditions so long as these practices do not conflict with fundamental Islamic law principles. Islamic law's openness to local influence is stymied in the Central Asian example because the edgen system that undergirds Central Asian elder care directly conflicts with the Islamic law of inheritance allotments. This article explains the edgen system and how it conflicts with Islamic law. A prominent contemporary Central Asian Islamic scholar's legal opinions illustrate a device in Islamic law called ḥiylah, or a legal ruse. Through this ruse, Central Asian families are able to maintain traditional elder care practices while also complying with Islamic law. Nevertheless, as the article concludes, the Central Asian elder-care system is based on unpaid female labor and female disinheritance. Female inheritance is a central feature of Islamic law. Yet, the edgen tradition puts women at a disadvantage in terms of labor and inheritance that Islamic law seeks to avoid.
Diclofenac sodium ion exchange resin complex loaded melt cast films for sustained release ocular delivery.

AbstractPurpose: The goal of the present study is to develop polymeric matrix films loaded with a combination of free diclofenac sodium (DFSfree) and DFS:Ion exchange resin complexes (DFS:IR) for immediate and sustained release profiles, respectively.Methods: Effect of ratio of DFS and IR on the DFS:IR complexation efficiency was studied using batch processing. DFS:IR complex, DFSfree, or a combination of DFSfree + DFS:IR loaded matrix films were prepared by melt-cast technology. DFS content was 20% w/w in these matrix films. In vitro transcorneal permeability from the film formulations were compared against DFS solution, using a side-by-side diffusion apparatus, over a 6 h period. Ocular disposition of DFS from the solution, films and corresponding suspensions were evaluated in conscious New Zealand albino rabbits, 4 h and 8 h post-topical administration. All in vivo studies were carried out as per the University of Mississippi IACUC approved protocol.Results: Complexation efficiency of DFS:IR was found ...
Effectiveness of Computer Automation for the Diagnosis and Management of Childhood Type 2 Diabetes: A Randomized Clinical Trial.

Importance Type 2 diabetes (T2D) is increasingly common in young individuals. Primary prevention and screening among children and adolescents who are at substantial risk for T2D are recommended, but implementation of T2D screening practices in the pediatric primary care setting is uncommon. Objective To determine the feasibility and effectiveness of a computerized clinical decision support system to identify pediatric patients at high risk for T2D and to coordinate screening for and diagnosis of prediabetes and T2D. Design, Setting, and Participants This cluster-randomized clinical trial included patients from 4 primary care pediatric clinics. Two clinics were randomized to the computerized clinical decision support intervention, aimed at physicians, and 2 were randomized to the control condition. Patients of interest included children, adolescents, and young adults 10 years or older. Data were collected from January 1, 2013, through December 1, 2016. Interventions Comparison of physician screening and follow-up practices after adding a T2D module to an existing computer decision support system. Main Outcomes and Measures Electronic medical record (EMR) data from patients 10 years or older were reviewed to determine the rates at which pediatric patients were identified as having a body mass index (BMI) at or above the 85th percentile and 2 or more risk factors for T2D and underwent screening for T2D. Results Medical records were reviewed for 1369 eligible children (712 boys [52.0%] and 657 girls [48.0%]; median [interquartile range] age, 12.9 [11.2-15.3]), of whom 684 were randomized to the control group and 685 to the intervention group. Of these, 663 (48.4%) had a BMI at or above the 85th percentile. Five hundred sixty-five patients (41.3%) met T2D screening criteria, with no difference between control and intervention sites. The T2D module led to a significant increase in the percentage of patients undergoing screening for T2D (89 of 283 [31.4%] vs 26 of 282 [9.2%]; adjusted odds ratio, 4.6; 95% CI, 1.5-14.7) and a greater proportion attending a scheduled follow-up appointment (45 of 153 [29.4%] vs 38 of 201 [18.9%]; adjusted odds ratio, 1.8; 95% CI, 1.5-2.2). Conclusions and Relevance Use of a computerized clinical decision support system to automate the identification and screening of pediatric patients at high risk for T2D can help overcome barriers to the screening process. The support system significantly increased screening among patients who met the American Diabetes Association criteria and adherence to follow-up appointments with primary care clinicians. Trial Registration clinicaltrials.gov Identifier:NCT01814787
Effective equidistribution for closed orbits of semisimple groups on homogeneous spaces

We prove effective equidistribution, with polynomial rate, for large closed orbits of semisimple groups on homogeneous spaces, under certain technical restrictions (notably, the acting group should have finite centralizer in the ambient group). The proofs make extensive use of spectral gaps, and also of a closing lemma for such actions.
In-situ reflectance monitoring of GaSb substrate oxide desorption

The use of specular reflectance to monitor GaSb substrate oxide desorption in-situ is reported. Substrates were loaded into the organometallic vapor phase epitaxy reactor either as-received (epi-ready) or after receiving a solvent degrease, acid etch and rinse. A variety of surface preparations and anneal conditions were investigated. HCL was used as the etchant, and in certain cases was followed by an additional etch in Br{sub 2}-HCl-HNO{sub 3}-CH{sub 3}COOH for comparison. Rinse comparisons included 2-propanol, methanol, and deionized water. Substrates were heated to either 525, 550, or 575 C. Features observed in the in-situ reflectance associated with the oxide desorption process were interpreted based on the starting oxide chemistry and thickness. Based on in-situ reflectance and ex-situ atomic force microscopy data, a recommendation on a reproducible GaSb substrate preparation technique suitable for high-quality epitaxial growth is suggested.
27-GAUGE VITRECTOMY WOUND INTEGRITY: A Randomized Pilot Study Comparing Angled Versus Straight Entry in Fluid-Filled Vitrectomized Eyes

PURPOSE To compare clinical outcomes using angled versus straight trocar insertion during 27-gauge pars plana vitrectomy for epiretinal membrane. METHODS Pilot randomized controlled trial. Thirty eyes of 30 patients undergoing 27-gauge pars plana vitrectomy with membrane peeling for epiretinal membrane were randomized 1:1 to receive angled or straight trocar insertion. Intraocular pressure (IOP) and postoperative wound-related complications were compared. RESULTS Fifteen eyes were randomized to each the angled and straight incision groups. No significant difference in phakic status (P = 0.71) or preoperative IOP (15.1 ± 3.4 vs. 14.6 ± 3.0 mmHg, P = 0.67) existed between groups. On postoperative Day 1, eyes in the straight group had lower IOP compared with the angled group (11.8 ± 3.9 vs. 15.3 ± 5.2 mmHg, P = 0.04) and a relative decrease in IOP compared with preoperative values (11.8 ± 3.9 vs. 15.1 ± 3.4 mmHg, P < 0.01). No IOP difference between groups was present at Day 7 (P = 0.43) or Day 30 (P = 0.42). Postoperative complications included transient hypotony (1 eye, straight group) and serous choroidal detachment (1 eye, angled group). CONCLUSION Eyes with straight incisions had transiently lower IOP on postoperative Day 1, possibly suggestive of subclinical wound leak in the very early postoperative period. Overall, rates of hypotony and sclerotomy-related complications were similarly low between wound construction strategies.
JOINT LINE ELEVATION IS ASSOCIATED WITH INCREASED POLYETHYLENE WEAR IN CRUCIATE-RETAINING TKR

Introduction Wear debris from polyethylene tibial inserts has been associated with limited longevity of total knee replacements (TKRs). While material factors were studied extensively and considerable progress has been made, there is little knowledge about surgical factors, particularly on how the wear rate is related to implant positioning. It was the purpose of this study to determine the combined effect of patient and implant positioning factors on the volumetric wear rate of TKRs. Our hypothesis was that implant alignment has a significant impact on the wear rate when controlled for other patient factors. Methods This study included 59 tibial inserts of a cruciate retaining TKR design (Nexgen, Zimmer Inc.). The patients9 age, sex, weight, height, and implant size were obtained. All implants were scanned with a coordinate measuring machine. Volumetric wear was determined using an autonomous mathematical reconstruction method (Figure 1). Radiographs were used to determine the anatomic lateral distal femoral angle (aLDFA), anatomic medial proximal tibial angle (aMPTA), femoral tilt angle (FTA) and posterior tibial slope (PTS). Also, the patella position was assessed using the Blackburne-Peel Index (BPI) and the Insall-Salvati Ratio (Figure 2). General linear modeling (SPSS) was conducted in order to determine the most significant patient and implant positioning factors on wear rate. Results After adjustment for creep, the mean volumetric wear rate was 11.6 mm 3 /yr (Figure 2). According to the linear regression model wear increased with younger age (p=0.0014) and male sex (p baja (p Discussion The effect of male sex on wear volume can partially be explained by a larger average implant size; however, other unknown confounding factors may play a role too. The effect of younger age is likely related to higher patient activity. Based on previous gait analysis, we speculate that increasing tibial slope results in larger AP translations of the knee joint and thus more wear. Interestingly, BPI remained a highly significant factor when controlled for all other factors. The average BPI clearly dropped post-operatively, whereas the average ISR did not, indicating that not true patella baja , but a joint line elevation occurred due to the reconstruction. Joint line elevation may affect the quadriceps mechanism leading to higher contact forces and subsequent higher wear. Post-operative joint line elevation can be explained by the intention to keep bone loss at a minimum, while using thick polyethylene inserts. Further studies are needed to determine the trade-offs between bone conservation and reduction of wear rate. However, this study has revealed the importance of surgical factors regarding polyethylene wear reduction in TKR. Acknowledgements This study was funded by NIH grant R01AR059843. For figures/tables, please contact authors directly.
A-Fast-RCNN: Hard Positive Generation via Adversary for Object Detection

How do we learn an object detector that is invariant to occlusions and deformations? Our current solution is to use a data-driven strategy &#x2013; collect large-scale datasets which have object instances under different conditions. The hope is that the final classifier can use these examples to learn invariances. But is it really possible to see all the occlusions in a dataset? We argue that like categories, occlusions and object deformations also follow a long-tail. Some occlusions and deformations are so rare that they hardly happen, yet we want to learn a model invariant to such occurrences. In this paper, we propose an alternative solution. We propose to learn an adversarial network that generates examples with occlusions and deformations. The goal of the adversary is to generate examples that are difficult for the object detector to classify. In our framework both the original detector and adversary are learned in a joint manner. Our experimental results indicate a 2.3% mAP boost on VOC07 and a 2.6% mAP boost on VOC2012 object detection challenge compared to the Fast-RCNN pipeline.
METAL RELEASE AND DAMAGE MECHANISMS IN AUTOPSY TOTAL KNEE ARTHROPLASTY FEMORAL COMPONENTS

Introduction Previous studies of CoCr alloy femoral components for total knee arthroplasty (TKA) have identified 3rd body abrasive wear, and apparent inflammatory cell induced corrosion (ICIC) [1] as potential damage mechanisms. The association between observed surface damage on the femoral condyle and metal ion release into the surrounding tissues is currently unclear. The purpose of this study was to investigate the damage on the bearing surface in TKA femoral components recovered at autopsy and compare the damage to the metal ion concentrations in the synovial fluid. Methods 12 autopsy TKA CoCr femoral components were collected as part of a multi-institutional orthopedic implant retrieval program. The autopsy components included Depuy Synthes Sigma Mobile Bearing (n=1) and PFC (n=1), Stryker Triathlon (n=1) and Scorpio (n=3), and Zimmer Nexgen (n=4) and Natural Knee (n=2). Fluoro scans of all specimens prior to removal was carried out to assure no signs of osteolysis or aseptic loosening were present. Third-body abrasive wear of CoCr was evaluated using a semi-quantitative scoring method similar to the Hood method [2]. ICIC damage was reported as location of affected area and confirmed using a digital optical microscope with 4000X magnification. Synovial fluid was aspirated from the joint capsule prior to removal of the TKA device. The synovial fluid was spun at 1600 rpm for 20 minutes in a centrifuge with the cell pellet removed. The supernatant was analyzed in 1 mL quantities for ICP-MS (inductively coupled plasma mass spectrometry) by Huffman Hazen Laboratories. Data was expressed as ppb. Results Mild to severe damage (Damage Score ≥ 2) was observed on 92% of the components in at least one quadrant, with no severe damage (Damage Score = 4) observed. ICIC damage was observed on three components in three different regions (the posterior lateral, anterior, and medial bearing surface). These observations were confirmed with digital optical microscopy, where we observed as interconnecting pits and indentations with a spiraling or trailing region, consistent with prior observation of ICIC in retrievals (Figure 1). Cobalt was detected in 7 cases, however the metal levels were not as high as levels observed in patients with a failed joint replacement (Table 1). There was no correlation between the metal ion concentration and the damage score on the CoCr femoral condyle. Discussion This study documents the damage mechanics and associated metallic release into the synovial fluid of “well-functioning” TKA components retrieved at autopsy. It has been suggested that ICIC damage is actually damage from electrocautery during surgery. However, we observed ICIC damage on autopsy retrievals in which the use of electrocautery is unlikely. The damage mechanisms observed on the autopsy TKA components were similar but less severe compared to mechanisms observed in long-term TKA components from revision surgery [1]. More research is needed to better understand the metal release from CoCr femoral components and periprosthetic tissue reactions in TKA.
How news and its context drive risk and returns around the world

Abstract We develop a classification methodology for the context and content of news articles to predict risk and return in stock markets in 51 developed and emerging economies. A parsimonious summary of news, including topic-specific sentiment, frequency, and unusualness (entropy) of word flow, predicts future country-level returns, volatilities, and drawdowns. Economic and statistical significance are high and larger for year ahead than monthly predictions. The effect of news measures on market outcomes differs by country type and over time. News stories about emerging markets contain more incremental information. Out-of-sample testing confirms the economic value of our approach for forecasting country-level market outcomes.
An experimental analysis of modifications to the survivor benefit information within the Social Security statement

The Social Security Statement is the primary resource most workers prefer to use to learn about their Social Security benefits. The Social Security Administration periodically mails this and supporting documents to all workers to help them make informed decisions about when to start receiving their benefits. Understandably, the Statement provides detailed information about the worker's retirement benefit. However, these documents contain remarkably little information about the survivor benefit despite the financial importance of this particular auxiliary benefit to the widows of deceased workers in widowhood. We analyze the effect of modifications to the survivor benefit information in the Statement on benefit knowledge and expected claiming behavior of married men using an experimental survey of workers. The results provide evidence that the augmentation of this information can temporarily improve benefit knowledge and influence expected claim ages.
The understatement of large negative earnings news in managers’ annual guidance☆

Abstract This study examines whether managers understate large negative earnings news in annual forecasts that are generally issued early when limited earnings information of the fiscal year is publicly available. I find that management forecasts of annual earnings conveying relatively large negative earnings news are systematically optimistic, and it is more (less) pronounced for firms with greater litigation risk or financial distress (net insider sale). The results suggest that fear of immediate lawsuits or job loss instead of trading opportunism motivates managers to understate large negative earnings news to mitigate immediate significantly negative consequences. I also provide evidence consistent with the market not identifying the bias in managers’ annual earnings guidance. This study has important implications for market participants relying on annual management forecasts to form earnings expectations early in the fiscal year and for regulators attempting to balance the quality and quantity of management guidance.
Effort Choices between Group and Individual Tasks in Mixed Incentives

ABSTRACT: Mixed individual and group incentives are widely used in practice under the assumption that by incentivizing both, organizations can increase total effort and predictably direct effort. T...
Analysis of a Classical Matrix Preconditioning Algorithm

We study a classical iterative algorithm for balancing matrices in the L∞ norm via a scaling transformation. This algorithm, which goes back to Osborne and Parlett 8 Reinsch in the 1960s, is implemented as a standard preconditioner in many numerical linear algebra packages. Surprisingly, despite its widespread use over several decades, no bounds were known on its rate of convergence. In this article, we prove that, for any irreducible n × n (real or complex) input matrix A, a natural variant of the algorithm converges in O(n3log (nρ/e)) elementary balancing operations, where ρ measures the initial imbalance of A and e is the target imbalance of the output matrix. (The imbalance of A is vlog(aiout/aiin)v, where aiout, aiin are the maximum entries in magnitude in the ith row and column, respectively.) This bound is tight up to the log n factor. A balancing operation scales the ith row and column so that their maximum entries are equal, and requires O(m/n) arithmetic operations on average, where m is the number of nonzero elements in A. Thus, the running time of the iterative algorithm is O(n2m). This is the first time bound of any kind on any variant of the Osborne-Parlett-Reinsch algorithm. We also prove a conjecture of Chen that characterizes those matrices for which the limit of the balancing process is independent of the order in which balancing operations are performed.
LoRa Backscatter: Enabling The Vision of Ubiquitous Connectivity

The vision of embedding connectivity into billions of everyday objects runs into the reality of existing communication technologies -- there is no existing wireless technology that can provide reliable and long-range communication at tens of microwatts of power as well as cost less than a dime. While backscatter is low-power and low-cost, it is known to be limited to short ranges. This paper overturns this conventional wisdom about backscatter and presents the first wide-area backscatter system. Our design can successfully backscatter from any location between an RF source and receiver, separated by 475 m, while being compatible with commodity LoRa hardware. Further, when our backscatter device is co-located with the RF source, the receiver can be as far as 2.8 km away. We deploy our system in a 4,800 ft2 (446 m2) house spread across three floors, a 13,024 ft2 (1210 m2) office area covering 41 rooms, as well as a one-acre (4046 m2) vegetable farm and show that we can achieve reliable coverage, using only a single RF source and receiver. We also build a contact lens prototype as well as a flexible epidermal patch device attached to the human skin. We show that these devices can reliably backscatter data across a 3,328 ft2 (309 m2) room. Finally, we present a design sketch of a LoRa backscatter IC that shows that it costs less than a dime at scale and consumes only 9.25 mW of power, which is more than 1000x lower power than LoRa radio chipsets.
Firm-level entry and exit dynamics over the business cycles

Abstract This paper presents a set of facts on the cyclicality of firm births and deaths in the U.S. during the period 1979–2013. Asymmetry in the cyclicality between firm birth and firm death is observed: aggregate firm birth is generally significantly procyclical, while the (counter-)cyclicality in firm death is ambiguous and sensitive to the choice of cyclical indicator. Such a pattern exists within the majority of sectors as well and is mainly driven by small firms. Young firms are the main contributors to the findings on firm death activity. Further examination along the time-dimension discovers a reason for the contemporaneous cyclicality (or lack thereof) which can be documented as a new fact: firm births positively lead the usual business cycle measures and firm deaths positively lag them. Moreover, cyclicality in business openings and closings differs from establishment level to firm level due to the internal adjustment of continuing firms.