Miracle-dz/UniFAR-FTUs huggingface dataset:
Social Insurance for the Elderly

Abstract We study the effects of retirement benefits provided by social insurance programs on consumption, portfolio choice, and retirement in a continuous-time theoretical model. We show that people tend to retire earlier with an increase in retirement social insurance benefits (SIBs), consistent with empirical evidence. We show also that people tend to increase savings before retirement in anticipation of increased retirement benefits, a counter-intuitive result. The response of risky investment with an increase in the SIBs is ambiguous, depending on parameter values. The overall social welfare will increase with an increase in SIBs if the balanced budget constraint is satisfied. We also investigate the effects of changes in the two streams of the SIBs (paid in perishable goods and cash) and the proportion of workers in entire population on social welfare.
The Asymmetric Impact of Oil Prices, Interest Rates and Oil Price Uncertainty on Unemployment in US

In this study, we investigate the presence of asymmetric interactions between oil prices, oil price uncertainty, interest rates and unemployment in a cointegration framework. Utilizing the nonlinear auto-regressive distributed lag (NARDL) approach, we show the asymmetric responses of unemployment to changes in oil prices, oil price uncertainty and interest rates in the long-run. More specifically, the results of our analyses suggest that an increase in oil price results in increased unemployment while there is no significant impact of reduced oil prices. On the other hand, reduced oil price uncertainty leads to a decrease in unemployment whereas an increase in oil price uncertainty does not have an impact. We also observe increased unemployment in response to a decrease in interest rates as the impact of increased interest rates is not significant. Last but not least, we find that option-implied oil price volatility, as a measure of oil price uncertainty, outperforms the conditional volatility of crude oil prices in predicting unemployment. This study provides valuable implications for policymakers to design sound economic policies.
Controle de plantas daninhas e seletividade do flumioxazin para eucalipto

A extensao de uso de herbicidas ja registrados para outras culturas, como o flumioxazin, se faz importante do ponto de vista do manejo integrado de plantas daninhas em plantios de eucalipto. Objetivou-se avaliar a eficacia de controle de plantas daninhas e a fitotoxicidade do flumioxazin aplicado isoladamente ou em mistura no tanque com isoxaflutole e sulfentrazone. Foi realizada a aplicacao desses herbicidas sobre plantas de eucalipto, utilizando pulverizador costal de precisao. Foram realizadas avaliacoes de porcentagem visual de intoxicacao, altura e diâmetro das plantas de eucalipto, e percentagem de massa seca e controle de plantas daninhas. Conclui-se que o flumioxazin e seletivo ao eucalipto ate a dose de 125 g. ha-1, embora possa acusar algum tipo de injuria que e plenamente recuperavel com o desenvolvimento das plantas. Sua eficacia de controle de plantas daninhas em pre-emergencia foi melhor quando em mistura no tanque com isoxaflutole e sulfentrazone.
Sex Ratios, Sexual Infidelity, and Sexual Diseases: Evidence from the United Kingdom

We extend a theory of fidelity in a two-sided economy, and empirically discriminate between different rationales of sexual network formation by testing their implications for how sex ratios affect sexual activity, relationship stability, and the spread of sexually transmitted diseases in men versus women. We use a unique individual-level dataset in combination with census data from England and Wales, a setting where adult women outnumber adult men. Exploiting variation in cohort/ethnicity/region-specific sex ratios as a quasi-natural experiment, we find that a decrease in sex ratio imbalance decreases sexual infidelity and the number of serial partners, and increases the likelihood of safe sex. This in turn reduces the likelihood of acquiring a range of sexually transmitted infections and diseases, including chlamydia, gonorrhoea, genital warts, and herpes. Consistent with the rationale underlying the formation of egalitarian (in)fidelity networks, the effects of the sex ratio on sexual activity are larger for men compared to women, while its effects on sexual diseases are larger for women compared to men. The causality of these effects is established using classical and recent instrumental variables approaches and various robustness checks. For falsification, we show that sex ratios have no impact on several ”atheoretical” health conditions, such as Parkinson’s disease, chronic lung disease, heart attack, stroke, and diabetes, which do not arise from sexual interactions.
Media Exposure and Stock Market Participation

We use a novel instrument--the local lineup position of business channels--to show that media exposure from cable television increases equity participation by increasing awareness of the stock market for first-time investors. Economically, a one-standard deviation reduction in the lineup position of business channels increases viewership by 6%. Subsequently, the propensity to invest in the stock market increases by 8.8% for the full sample and rises to 21.3% for first-time investors induced into watching by variation in channel position. Media exposure also reduces the likelihood these first time investors exit, keeping them in the stock market for longer.
Expression of fucosylated antigens and α1,3 fucosyltransferases in human leukaemia cell lines

The expression of alpha 1,3 fucosylated type 2 antigens is generally thought to be restricted to myeloid cells among normal human haemopoietic tissue. The distribution of three fucosylated antigens [Lewis X (Le(x)), sialyl Lewis X (sLex) and VIM2] was investigated among nine human leukaemia cell lines by fluorescence activated cell sorting (FACS) analysis. As expected, all myeloid cell lines were positively stained by antibodies against these three fucosylated antigens. Unexpectedly, two T-lymphocytic cell lines (CCRF-CEM and MOLT4) were found to express Le(x) and VIM2, and the plasma, B-cell line, RPMI 8226, expressed all three fucosylated antigens. Enzymatic and RNA analyses [Northern blot and reverse transcription polymerase chain reaction (RT-PCR)] were used to evaluate possible control points in the biosynthetic pathway for Le(x) and sLex. beta 1,4 Galactosyltransferase (beta 1,4GalT, an enzyme involved in the synthesis of the core oligosaccharide of the three fucosylated antigens) activity and the corresponding mRNA were found in all of the leukaemia cell lines, regardless of whether or not they expressed the fucosylated antigens. In contrast, alpha 1,3 fucosyltransferase (GDP-fucose:beta-D-N-acetylglucosaminide 3-alpha-L-fucosyltransferase; alpha 1,3FT) activity and the corresponding mRNA were found only in those cell lines expressing fucosylated antigens. Based on RNA analysis, acceptor specificity and N-ethylmaleimide inhibition studies, it was concluded that all of the cell lines expressing fucosylated antigens contained alpha 1,3FTIV (myeloid alpha 1,3FT). This appeared to be the major alpha 1,3FT in the myeloid and T-lymphocytic cell lines. Interestingly, even though both types of cell lines expressed the same alpha 1,3FT, only the myeloid cell lines expressed sLex, whereas all of the myeloid and T-lymphocytic cell lines expressed a structural analogue of sLex (i.e. VIM2). In contrast to the myeloid and T-cell lines, RPMI 8226 cells contained more than one fucosyltransferase activity. Acceptor specificity analysis demonstrated that this cell line contains alpha 1,3 and alpha 1,4FTs. Among the fucosyltransferases expressed by RPMI 8226, alpha 1,3FTIV accounted for only a small amount of the total activity. The results of this study demonstrate that fucosylated antigens, which are generally considered to be myeloid specific antigens, are also expressed by lymphocytic leukaemia cell lines, and that the types of fucosylated antigens and fucosyltransferases expressed in these cell lines vary.
Naked Short Selling and the Market Impact of Failures-to-Deliver: Evidence from the Trading of Real Estate Investment Trusts

We investigate the impact of failures-to-deliver on the performance of 116 Real Estate Investment Trusts (REITs) during a period of substantial short selling (calendar years 2007 and 2008). REIT shares typically are easy to borrow, have high transparency (low information asymmetry), and are exposed to systematic risk during the sample period, making them short sale targets. We find that the majority of failure-to-deliver events are quickly resolved, with durations of less than three days. Our results support the conjecture that most failures-to-deliver result from short sellers covering their trades before the settlement date of the initial sale. Since the failure is resolved when the covering purchase settlement day arrives, traders forego borrowing which results in a failure-to-deliver. However, failures-to-deliver that are outstanding for many days have lower risk adjusted returns. Our results support the actions taken by the SEC in September of 2008 to tighten the delivery requirement of stock trades.
Service Provision in Distribution Channels

Consumers may need help using an inherently complex product after purchase. This article studies a manufacturer's and a retailer's incentives to provide presales service and after-sales support in a distribution channel. The authors consider a model in which a manufacturer makes wholesale price and channel service decisions. Subsequently, a retailer makes retail price and channel service decisions. They find that, in equilibrium, both channel members provide presales service. If the fixed-cost investment needed to enhance the effectiveness of after-sales support is small, the manufacturer lets the retailer provide after-sales support. Yet when it is above a threshold and the retailer becomes unwilling to invest in providing after-sales support, the manufacturer steps in and does so. As expected, when the fixed cost is too large, the manufacturer also opts out of providing after-sales support. Interestingly, when the retailer provides after-sales support, the level of presales service and the demand for after-sales support can simultaneously be the highest among all configurations. Finally, the authors demonstrate the robustness of their main results by studying alternative channel service configurations.
Defensive Innovations

Defensive innovations in developed countries can explain the empirical phenomenon that openness towards trade with less-developed countries does not necessarily induce a substantial increase in the wage differential and trade volumes. Building on step-by-step innovations as introduced by Aghion et al. (2001), we show that defensive innovations can result from private incentives. In particular, minimum wages can induce defensive innovations which then redistribute income away from workers. Suggestive empirical evidence is consistent with the implications of defensive innovations for wage differentials, trade volumes and the sectorial composition within and across OECD countries.
The Nexus between the Oil Price and Stock Market: Evidence from South Asia

The link between stock market prices and oil prices has drawn considerable attention in recent decades because the risk and uncertainties associated with oil price volatility affect investor’s portfolios, particularly, those investors seeking to make optimal portfolio allocations. This paper investigates the relationship between the oil price and the stock market index in South Asia. Based on a sample of four countries, namely Bangladesh, India, Pakistan, and Sri Lanka for the period 1997-2017, we use the nonlinear Autoregressive distributed model estimated by Pooled Mean Group (PMG) estimator. We show that there is a positive relationship between the world oil price and stock market index; and that the response of stock market index to positive and negative oil price shocks are asymmetric. Counter to prior research in developing countries, our findings imply that higher oil prices in the world market stimulate stock prices which suggests that the stock markets in the South Asian region do not follow the Efficient Market Hypothesis (EMH) for which the shocks in the crude oil market are not rationally signaled in the financial market. Another plausible justification of this movement in the same direction, as explained by Bernanke (2016), is that both oil price and stock prices are reacting to a change in some common underlying factor, which he calls the global aggregate demand and market risk aversion.
Crop Productivity and Nutrient Dynamics in a Shrub‐Based Farming System of the Sahel

Piliostigma reticulatum (DC.) Hochst. , an indigenous shrub, forms an important vegetative component of parkland cropping systems in the Sahel; however, its biophysical interactions with soil and crops are not well understood. Therefore, the objectives were to determine the impact of P. reticulatum, under varying fertilizer rates, on crop yield response and soil nutrient dynamics. The experiment had a split-plot factorial design, where the main plot was shrub (presence or absence) and the subplot was fertilizer rate (0, 0.5, 1.0, or 1.5 times the recommended N–P–K fertilizer rate) applied to a peanut (Arachis hypogaea L.)–pearl millet [Pennisetum glaucum (L.) R. Br. ] rotation. In 3 of the 4 yr, P. reticulatum improved or had no effect on crop yields when averaged across fertilizer rates. Overall, millet and peanut biomass and N and P uptake by millet increased in the presence of shrubs and with increasing fertilizer rate. Contrary to P, inorganic N in the soils changed very rapidly, reaching very low levels by the end of the growing season. The N content of soil leachates below the rooting zone was generally lower beneath than outside the shrub canopy, suggesting that the shrub conserves N that is otherwise lost through leaching. Piliostigma reticulatum increased particulate organic matter, indicating that this shrub improved soil quality. These results suggest that P. reticulatum, under nonthermal management and a higher density than typically found in farmers’ fields, has ecological benefits with improved soils and reduced loss of N, which has implications throughout the Sahel.
The Effect of Phonological Ability on Math is Modulated by Socioeconomic Status in Elementary School

Math achievement is affected by social factors such as socioeconomic status (SES) and domain-general cognitive factors such as phonological ability. Little is known how the effects of cognitive factors change depending on social factors during development. This study focuses on the estimation of the effect of phonological ability on math achievement during the first year of schooling and testing the hypothesis that this effect varied depending on students SES. To achieve our aims we used two-wave longitudinal study which was conducted on large sample of first-graders (N= 2,948) in the Tatar Republic (Russia). Participants were assessed twice, at the beginning and at the end of the first grade (mean age was 7.3 years at Time 1). The item response theory (IRT) scaling procedure was used to estimate individual scores in math, number identification, phonology and reading. In order to estimate the effect of phonological ability and SES on math performance, mixed-effect longitudinal models were applied. The results revealed that phonological ability had a significant positive effect on math achievement even when reading achievement, number identification and SES were controlled for. Among SES dimensions only maternal education had an effect on math achievement and its improvement. The effect of phonological ability was higher for students with a larger number of books at home and who used more than one language at home.
Is There Valuable Private Information in Credit Ratings?

Abstract Credit rating agencies (CRAs) contend their ratings contain a quantitative assessment based on hard information, and a qualitative adjustment based on private information. We study if the qualitative portion of ratings, generated with the companies’ own private information, contains valuable information for equity investors. We generate predicted ratings based on hard information alone and form portfolios of stocks based on the difference between observed and predicted ratings. Over a sample from 1998 to 2018, we find that stock portfolios formed on the basis of private information generate 2% to 4% in annual risk-adjusted returns. We also find that companies with positive private information have better future accounting performance. Our results suggest that CRAs bring valuable information to the market and investors could benefit from it.
A Linear Programming Model for Selecting Sparse High-Dimensional Multi-period Portfolios

This paper studies the mean-variance (MV) portfolio problems under static and dynamic settings, particularly for the case that the number of assets ($p$) is larger than the number of observations ($n$). We prove that the classical plug-in estimation seriously distorts the optimal MV portfolio in the sense that the probability, that the plug-in portfolio will outperform the bank deposit, tends to 50\% for $p\gg n$ and a large $n$. We investigate a constrained $\ell_1$ minimization approach for directly estimating effective parameters appearing in the optimal portfolio solution. The proposed estimator is efficiently implemented with linear programming and the resulting portfolio is called the linear programming optimal (LPO) portfolio. We derive the consistency and the rate of convergence for the LPO portfolios. The LPO procedure essentially filters out unfavorable assets based on the MV criterion, resulting in a sparse portfolio. The advantages of the LPO portfolio include its computational superiority and its applicability for dynamic settings and non-Gaussian distributions of asset returns. Simulation studies validate the theory and illustrate its finite-sample properties. Empirical studies show that the LPO-based portfolios outperform the equally weighted portfolio, and the estimated optimal portfolios using shrinkage and other competitive estimators.
Understanding the Motives for Director Selection

Director selection is crucial in corporate governance, but little is known about the relative importance of individual director attributes in the selection process. We examine the motives for director selection using the empirical setting of mergers, which offers a well-defined pool of candidates considered and a discrete shock to a board’s monitoring and advising needs. We find that boards increase director expertise tied to these changing needs, even in cases with powerful CEOs that could opportunistically weaken board monitoring. Individual candidates with expertise related to changing board needs are significantly more likely to be selected for the post-merger board. In contrast, directors are appointed from outside of the well-defined labor pool when they possess more related expertise than candidates from the merging firms. Our evidence suggests that directors are selected to meet changing monitoring and advising needs.
Does More Complex Language in FOMC Decisions Impact Financial Markets?

This paper is built around a simple premise that is based on the theoretical models of Harris and Raviv (1993) and Kandel and Pearson (1995). Complex statements are more difficult to interpret and may be construed in different ways by different agents. This creates heterogeneity of beliefs among market participants that manifests in increased market activity. We confirm existing results that show monetary policy surprises have a significant impact on financial markets. Importantly, we demonstrate that linguistic complexity (measured in terms of readability and number of words) of FOMC statements that accompany monetary policy decisions significantly increases the trading volume, and volatility of returns, in stock, bond, and currency markets. We also establish that financial markets are more responsive to monetary policy decisions (and the language of those statements) during recession.
Root anatomy of palms III. Ceroxyloideae, Nypoideae, Phytelephantoideae

Summary The root-anatomy of representatives of nine genera of Ceroxyloideae of the eleven genera accepted by UHL & DRANSFIELD (1987), of Nypa, the onliest genus of Nypoideae, and of all three genera of Phytelephantoideae have been studied. In Coryphoideae and Calamoideae every genus can be distinguished by the anatomy of the roots, whereas within one genus the species do not differ but slightly. This is true for the newly examined genera too and contributes both to define and identify the genera and towards an improved understanding of the relationship between genera and subfamilies. The genera of Ceroxyloideae are obviously related, they form a natural group, and even the somewhat isolated Pseudophoenix is well at home here. Both Nypa and Phytelephantoideae do not exhibit any affinities with other palms studied up to now. Zusammenfassung Die Arbeit behandelt die Wurzelanatomie von neun der elf Gattungen der Ceroxyloideae sowie von Nypa, der einzigen Gattung der Nypoideae, und aller drei Gattungen der Phytelephantoideae. Die Gattungen unterscheiden sich erwartungsgemas in ihrer Wurzelanatomie deutlich, die Arten einer Gattung aber nur unwesentlich oder quantitativ. Dies erlaubt es, die Gattungen abzugrenzen und verwandtschaftliche Beziehungen sowohl zwischen den Gattungen als auch zwischen den Triben aufzuzeigen. Die Unterfamilie der Ceroxyloideae erweist sich in ihrer Wurzelanatomie homogen; die isolierte Gattung Pseudophoenix findet ihren Anschlus innerhalb der Ceroxyloideen. Die Ceroxyloideen teilen mit den Coryphoideen einige Merkmale, zu den Calamoideen haben sie keinerlei Beziehungen. Die Gattungen der Phytelephantoideen sind aufgrund ihrer Wurzelanatomie gut gegeneinander abgrenzbar, was angesichts ihrer grosen Ahnlichkeit uberrascht. Sowohl die Phytelephantoideen als auch Nypa zeigen den typischen Aufbau der Palmenwurzel, die Kombination ihrer Merkmale last jedoch keinerlei Verbindungen zu den Coryphoideen, Calamoideen und Ceroxyloideen erkennen.
Board Size, Firm Risk and Equity Discount

Prior literature documents that larger boards pursue conservative investment policies and that their decision outcomes are moderate which promote an environment of risk-aversion. I argue that this risk-aversion hurts equity holders when firms hold a larger amount of long-term debt. Addressing potential endogeneity problems associated with board size, I find an equity discount associated with larger boards in firms that have greater amounts of long-term debt. On the other hand, larger boards are associated with an equity premium when firms have a greater short-term debt to assets ratio. The equity discount associated with larger boards disappears in firms with no long-term debt. Further analysis also indicates that firms with larger boards enjoy a better credit rating and a lower realized cost of debt. Overall, analysis in this study suggests that the association between board size and equity value is a function of a firm’s debt structure.