Miracle-dz/UniFAR-FTUs huggingface dataset:
Ethnic Divisions and Production in Firms

A body of literature suggests that ethnic heterogeneity limits economic growth. This paper provides microeconometric evidence on the direct effect of ethnic divisions on productivity. In team production at a plant in Kenya, an upstream worker supplies and distributes flowers to two downstream workers who assemble them into bunches. The plant uses an essentially random rotation process to assign workers to positions, leading to three types of teams: (a) ethnically homogeneous teams, and teams in which (b) one or (c) both downstream workers belong to a tribe in rivalry with the upstream worker’s tribe. I find strong evidence that upstream workers undersupply non-coethnic downstream workers (vertical discrimination) and shift flowers from non-coethnic to coethnic downstream workers (horizontal discrimination), at the cost of lower own pay and total output. A period of ethnic conflict following Kenya’s 2007 election led to a sharp increase in discrimination. In response, the plant began paying the two downstream workers for their combined output (team pay). This led to a modest output reduction in (a) and (c) teams - as predicted by standard incentive models - but an increase in output in (b) teams, and overall. Workers’ behavior before conflict, during conflict, and under team pay is predicted by a model of taste-based discrimination. My findings suggest that inter-ethnic rivalries lower allocative efficiency in the private sector, that the economic costs of ethnic diversity vary with the political environment, and that in high-cost environments firms are forced to adopt “second best” policies to limit discrimination distortions.
U of South Florida CAREER : Performance Evaluation of Gigabit Ethernet Networks , A Systems and Experimental Approach Participant Individuals : Graduate student

I have collaborated with Alan George (faculty) at the University of Florida, Neil Gunther (consultant) at Performance Dynamics, Aju Jacob (student) at the University of Florida, Joe Rogers (graduate student and now staff) at the University of South Florida, Allen Roginsky (mathematician) at IBM Corporation, and Marcel Waldvogel (researcher) at IBM Corporation. Neil, Aju, Joe, Allen, and I have worked on collaborative papers. Involved in this collaboration have been the students funded by this CAREER grant. Alan and I established a new workshop on high-speed local networks. Marcel and I co-edited a special issue of Computer Communications on Terabit switching.
Associated disorders in myasthenia gravis: autoimmune diseases and their relation to thymectomy

ABSTRACT— The prevalence of myasthenia gravis (MG) in the counties of Hordaland and Sogn & Fjordane on January 1, 1984 was 9.6 per 100,000 inhabitants. Other autoimmune diseases were found in 11 out of 48 MG patients. The occurrence of autoimmune thyroiditis (5 patients, 10.4%) and systemic lupus erythematosus (4 patients, 8.3%) in the MG patients was clearly higher than that reported in the general population. Rheumatoid arthritis was found in 2 patients (4.2%). The autoimmune diseases were mainly recorded among the nonthymectomized MG patients. In addition to those with definite diseases of autoimmune nature, 3 other MG patients had thyroid antibodies and 1 had antinuclear factor without clinical evidence of autoimmune disease. Seven MG patients (14.6%) had unspecific arthralgia during active periods of MG. Two MG patients had ankylosing spondylitis.
Environmental correlates of intercity variation in age-adjusted cancer mortality rates

Factors contributing to urban differences in cancer mortality rates are difficult to specify because of migration and the delay between exposure to carcinogens and manifestations of the disease. Proxy measures for prior migration, motor vehicle emissions, industrial pollution, factors in the water supplies, and climate, explain more than half the intercity variation in age-adjusted cancer mortality rates among 98 cities in the U.S. in 1970. The potential importance of these environmental factors as the “urban factor” in cancer is discussed.
Detecting Myocardial Ischemia at Rest With Cardiac Phase–Resolved Blood Oxygen Level–Dependent Cardiovascular Magnetic Resonance

Background— Fast noninvasive identification of ischemic territories at rest (before tissue-specific changes) and assessment of functional status can be valuable in the management of severe coronary artery disease. This study investigated the use of cardiac phase–resolved blood oxygen level–dependent (CP-BOLD) cardiovascular magnetic resonance in detecting myocardial ischemia at rest secondary to severe coronary artery stenosis. Methods and Results— CP-BOLD, standard cine, and T2-weighted images were acquired in canines (n=11) at baseline and within 20 minutes of ischemia induction (severe left anterior descending stenosis) at rest. After 3 hours of ischemia, left anterior descending stenosis was removed, and T2-weighted and late-gadolinium-enhancement images were acquired. From standard cine and CP-BOLD images, end-systolic and end-diastolic myocardium was segmented. Affected and remote sections of the myocardium were identified from postreperfusion late-gadolinium-enhancement images. Systolic-to-diastolic ratio (S/D), quotient of mean end-systolic and end-diastolic signal intensities (on CP-BOLD and standard cine), was computed for affected and remote segments at baseline and ischemia. Ejection fraction and segmental wall thickening were derived from CP-BOLD images at baseline and ischemia. On CP-BOLD images, S/D was >1 (remote and affected territories) at baseline; S/D was diminished only in affected territories during ischemia, and the findings were statistically significant (ANOVA, post hoc P<0.01). The dependence of S/D on ischemia was not observed in standard cine images. Computer simulations confirmed the experimental findings. Receiver-operating characteristic analysis showed that S/D identifies affected regions with performance (area under the curve, 0.87) similar to ejection fraction (area under the curve, 0.89) and segmental wall thickening (area under the curve, 0.75). Conclusions— Preclinical studies and computer simulations showed that CP-BOLD cardiovascular magnetic resonance could be useful in detecting myocardial ischemia at rest. Patient studies are needed for clinical translation.
The microbiota associated with implants restored with platform switching: a preliminary report.

BACKGROUND It was demonstrated that implants restored according to a platform-switching concept presented less crestal bone loss than implants restored with standard protocols. The aim of this study is to examine differences between the composition of the peri-implant microbiotas associated with implants restored with the platform-switching approach and implants restored with a standard internal connection protocol. METHODS A total of 48 implants were examined in 18 subjects: 33 implants were restored with platform switching, and 15 implants were restored using the traditional approach. Thirty-six months after prosthetic loading, subgingival plaque samples were taken from the mesio- and disto-buccal aspects of each implant and from one tooth adjacent to one of the implants in each subject. The levels of 40 subgingival species were measured using checkerboard DNA-DNA hybridization. Microbiologic parameters were averaged within each subject and across subjects in each clinical group (platform switching versus control) and site category (implants versus teeth) separately. The significance of differences between clinical groups and site categories was determined using the Mann-Whitney test and the Wilcoxon test, respectively. RESULTS There were no statistically significant differences between groups for any of the species. The platform-switching group showed a small trend for lower levels of early colonizer members of the Actinomyces, purple and yellow complexes, Campylobacter species, Tannerella forsythia (previously T. forsythensis), and Porphyromonas gingivalis. Teeth and implants presented similar microbial profiles. CONCLUSION The results of the study suggest that the difference in bone crest resorption between implants restored with platform switching compared to traditionally restored implants is not associated with differences in the peri-implant microbiota.
Digital Immunization Surveillance: Monitoring Flu Vaccination Rates Using Online Social Networks

Influenza immunizations are critical for preventing deadly and costly outbreaks within the United States, yet flu vaccination coverage has annually remained low. Flu vaccination monitoring is important since early detection of anomalies in flu vaccination rates allows faster communication among public health agencies and local governments thereby facilitating rapid deployment of flu vaccination campaigns.Currently, there is no real-time detection mechanism for monitoring flu vaccination rates. Traditional flu vaccination rate tracking systems suffer information lags due to reliance on reports submitted by medical practices which are updated only once a week. In this paper, we demonstrate the feasibility of a real-time, low-cost and labor-efficient alternative monitoring method to the flu vaccination rate surveillance system used by the United States Department of Health and Human Services (HHS). This alternative is based on social network data and specifically Twitter data. We demonstrate the viability of this approach by measuring the level of correlation between the frequency of "tweets" mentioning flu vaccinations and HHS data on flu vaccination rates.
Membrane‐targeting sequences on AKAP79 bind phosphatidylinositol‐4,5‐bisphosphate

Protein kinases and phosphatases are targeted through association with anchoring proteins that tether the enzymes to subcellular structures and organelles. Through in situ fluorescent techniques using a Green Fluorescent Protein tag, we have mapped membrane‐targeting domains on AKAP79, a multivalent anchoring protein that binds the cAMP‐dependent protein kinase (PKA), protein kinase C (PKC) and protein phosphatase 2B, calcineurin (CaN). Three linear sequences termed region A (residues 31–52), region B (residues 76–101) and region C (residues 116–145) mediate targeting of AKAP79 in HEK‐293 cells and cortical neurons. Analysis of these targeting sequences suggests that they contain putative phosphorylation sites for PKA and PKC and are rich in basic and hydrophobic amino acids similar to a class of membrane‐targeting domains which bind acidic phospholipids and calmodulin. Accordingly, the AKAP79 basic regions mediate binding to membrane vesicles containing acidic phospholipids including phosphatidylinositol‐4,5‐bisphosphate [PtdIns(4,5)P2] and this binding is regulated by phosphorylation and calcium‐calmodulin. Finally, AKAP79 was shown to be phosphorylated in HEK‐293 cells following stimulation of PKA and PKC, and activation of PKC or calmodulin was shown to release AKAP79 from membrane particulate fractions. These findings suggest that AKAP79 might function in cells not only as an anchoring protein but also as a substrate and effector for the anchored kinases and phosphatases.
Forecasting socioeconomic trends with cell phone records

National Statistical Institutes typically hire large numbers of enumerators to carry out periodic surveys regarding the socioeconomic status of a society. Such approach suffers from two drawbacks:(i) the survey process is expensive, especially for emerging countries that struggle with their budgets and (ii) the socioeconomic indicators are computed ex-post i.e., after socioeconomic changes have already happened. We propose the use of human behavioral patterns computed from calling records to predict future values of socioeconomic indicators. Our objective is to help institutions be able to forecast socioeconomic changes before they happen while reducing the number of surveys they need to compute. For that purpose, we explore a battery of different predictive approaches for time series and show that multivariate time-series models yield R-square values of up to 0.65 for certain socioeconomic indicators.
Monopoles over 4-manifolds containing long necks, I

We establish a gluing theorem for monopoles over 4–manifolds containing long necks. The theorem is stated in terms of an ungluing map defined explicitly in terms of data that appear naturally in applications. Orientations of moduli spaces are handled using Benevieri–Furi’s concept of orientations of Fredholm operators of index 0.
Steroid potentiation of responses to sympathomimetic amines in aortic strips

1 Responses to catecholamines (adrenaline, noradrenaline, nordefrine) were enhanced by 17β‐oestradiol, progesterone and desoxycorticosterone in untreated and reserpine pretreated aortic strips. Responses to tyramine, believed mediated via endogenous catecholamines, were enhanced only in untreated strips. 2 Responses to sympathomimetic amines lacking the catechol nucleus (phenylephrine, synephrine, methoxamine) were potentiated inconsistently by the steroids and reserpine pretreatment reduced markedly the frequency of potentiated responses. 3 Known inhibitors of catechol‐O‐methyl transferase (tropolone, U‐0521, pyrogallol) potentiated responses to catecholamines and abolished the enhancing effects of the steroids—when the steroids were given first, there was no further increase in response to catecholamines on adding inhibitors of catechol‐O‐methyl transferase. 4 Experiments with the oil‐immersion technique, to eliminate diffusion of drug from the tissue, indicated that 17β‐oestradiol, progesterone and desoxycorticosterone decreased the rate at which aortic strips inactivated adrenaline by Omethylation. 5 It is concluded that 17β‐oestradiol, progesterone and desoxycorticosterone potentiate responses to catecholamines in aortic strips by inhibiting a major mechanism for their inactivation.
Heterogeneous Continuous Dynamic Bayesian Networks with Flexible Structure and Inter-Time Segment Information Sharing

Classical dynamic Bayesian networks (DBNs) are based on the homogeneous Markov assumption and cannot deal with heterogeneity and non-stationarity in temporal processes. Various approaches to relax the homogeneity assumption have recently been proposed. The present paper aims to improve the shortcomings of three recent versions of heterogeneous DBNs along the following lines: (i) avoiding the need for data discretization, (ii) increasing the flexibility over a time-invariant network structure, (iii) avoiding over-flexibility and overfitting by introducing a regularization scheme based in inter-time segment information sharing. The improved method is evaluated on synthetic data and compared with alternative published methods on gene expression time series from Drosophila melanogaster.
A Model of Large-Scale proteome Evolution

The next step in the understanding of the genome organization, after the determination of complete sequences, involves proteomics. The proteome includes the whole set of protein-protein interactions, and two recent independent studies have shown that its topology displays a number of surprising features shared by other complex networks, both natural and artificial. In order to understand the origins of this topology and its evolutionary implications, we present a simple model of proteome evolution that is able to reproduce many of the observed statistical regularities reported from the analysis of the yeast proteome. Our results suggest that the observed patterns can be explained by a process of gene duplication and diversification that would evolve proteome networks under a selection pressure, favoring robustness against failure of its individual components.
Identification of sources and infiltration regimes of nitrate in the semi-arid Kalahari: Regional differences and implications for groundwater management

The Kalahari region of southern Africa offers much potential for nitrogen input into its groundwater. High nitrate concentrations in Kalahari groundwater are therefore quite common and are caused by both anthropogenic and natural sources. Forecasting groundwater nitrate concentrations remains challenging. Source identification of nitrate contamination in groundwater is an important first step for groundwater management and quality prediction, and is aided by isotope analysis of nitrate in the water. Comparative data from 3 groundwater study sites in the Kalahari of Botswana and Namibia with widely different characteristics are presented. Two of the sites (Ghanzi and Gobabis) have shallow water tables in fractured quartzite. These aquifers were affected by pollution from cattle wastes (manure) and septic tank outflows resulting in groundwater nitrate levels exceeding 1 000 mg NO3/. and in ƒÂ15N values of between +7 and +20 n AIR. Short-term increases of groundwater nitrate concentrations were triggered by exceptional rainfall events occurring every 10-20 years. At the third site (Serowe in Botswana) there is similar land use and land cover, yet the aquifers are deeper, groundwater dates to Late-Pleistocene age and borehole levels do not show a response to present-day high-rainfall episodes. Nitrate levels up to 219 mg/. are found, but lower 15N content (ƒÂ15N of +3 to +8 n) indicates a natural origin of the nitrate. In this area pollution nitrate is sufficiently delayed in the vadose zone, reaching the saturated zone much later. The data from all 3 sites suggest that nitrogen management options can only be evaluated once an understanding of sources, processes and flow patterns has been established.
Galactic planetary nebulae with Wolf-Rayet nuclei II. A consistent observational data set ?;??

We present high resolution spectrophotometric data for a sample of 34 planetary nebulae with (WC) spectral type central stars (WRPNe) in our Galaxy. The observed objects cover a wide range in stellar charac- teristics: early and late (WC) type stars, as well as weak-emission line stars (WELS). Physical conditions in the nebulae (electron density and temperatures) have been obtained from various diagnostic line ratios, and chemical abundances have been derived with the usual empirical scheme. Expansion velocities were estimated in a con- sistent manner from the line proles for most objects of the sample. A statistical study was developed for the derived data in order to nd fundamental relationships casting some light on the evolutionary status of WRPNe. We found evidence for a strong electron temperature gradient in WRPNe which is related to nebular excitation. Such a gradient is not predicted in simple photoionization models. Abundance ratios indicate that there seems to be no preferential stellar mass for the Wolf-Rayet phenomenon to occur in the nucleus of a planetary nebula. Two objects, M 1-25 and M 1-32, were found to have a very small Ne/O ratio, a property dicult to understand. We reexamined the relation between the nebular properties of the WRPNe and the spectral types of the central stars. Our data conrm the trend found by other authors of the electron density decreasing with decreasing spectral type, which was interpreted as evidence that (WC) stars evolve from late to early (WC) types. On the other hand, our data on the expansion velocities do not show the increase of expansion velocity with decreasing spectral type, that one might expect in such a scenario. Two objects with very late (WC) type central stars, K 2-16 and PM 1-188, do not follow the general density sequence, being of very low density for their spectral types. We suggest that the stars either underwent a late helium flash (the \born again" scenario) or that they have had a particularly slow evolution from the AGB. The 6 WELS of our sample follow the same density vs. (WC)-type relation as the bona de WRPNe, but they tend to have smaller expansion velocities. Considerations about the evolutionary status of WELS must await the constitution of a larger observational sample. The analysis of the dierences between the WRPNe in the Magellanic Clouds (distribution of (WC) spectral types, N/O ratios) and in the Galaxy indicates that metallicity aects the (WR) phenomenon in central stars of planetary nebulae.
Growth and Capital Flows with Risky Entrepreneurship

Contrary to the prediction of standard permanent income growth models, faster growing developing countries tend to experience net capital outflows. In this paper, I show that a small open economy model featuring endogenous entrepreneurship and uninsurable idiosyncratic risk can account for the empirical evidence. I consider an economy in which agents are initially prevented from undertaking private business activities and study its dynamic evolution once this constraint is removed. The individuals with sufficiently high entrepreneurial ability start up their own firms generating a prolonged period of growth. The key insight of the model is that since the entrepreneurial activities are subject to the uninsurable risk of bankruptcy, entrepreneurs increase together with the amount of invested capital also their holdings of safe assets. This leads to the improvement of the country’s net foreign asset position, thus accounting for the observed net capital outflows. The welfare costs due to the lack of insurance are found to be substantial especially at the beginning to the transition period.
Root kinematics in relation to temperature and genome size in wild and domesticated Zea.

TITLE: Root kinematics in relation to temperature and genome size in wild and domesticated Zea. ABSTRACT Root kinematics in relation to temperature and genome size in wild and domesticated Zea. We studied root kinematics in relation to temperature and genome size variation in teosinte (Zea mays subspecies parviglumis) and corn (Zea mays subspecies mays). Corn had significantly faster radicle growth than teosinte when grown at a constant temperature. Both species exhibited variation in seed size and for each species larger seeds had faster root growth. Genome size was not significantly correlated with faster radicle growth rates across multiple land races of corn. To examine temperature dependent growth in corn and teosinte, a germinated seedling was grown at multiple temperatures. Growth rates at these temperatures were used to fit a temperature response model for each species. Parameters of this model (maximum growth temperature and optimum growth temperature) were not significantly different between the species. ACKNOWLEDGMENTS This paper was only accomplished through the generous time contributions of committee members and through the invaluable collaborative efforts of Concepción M. Díez.
A Study of Autocorrelatons and Lead-Lag Efiects Using Game-Theoretic E-cient-Market Hypotheses

A network system includes a wavelength-multiplexing transmission path for multiplexing and transmitting a plurality of wavelengths, and a plurality of terminal equipments connected to the transmission path. A transmission wavelength and a reception wavelength are assigned in advance to each of the plurality of terminal equipments. When data must be transmitted between the terminal equipments, and when a transmission wavelength of a transmission source terminal equipment as a transmission source of the data is diffenrent from a reception wavelength of a destination terminal equipment as a destination of the data, wavelength conversion is performed such that a terminal equipment located between the transmission source terminal equipment and the destination terminal equipment temporarily receives the data, and transmits the data at another wavelength.