Miracle-dz/UniFAR-FTUs huggingface dataset:
Earning Structure and Heterogeneity of the Labor Market: Evidence from DR Congo

Using 1.2. 3 survey data on the Democratic Republic of Congo, we highlight different sectors in the labor market, with ‘higher paid’ sectors that are largely formal and ‘lower paid’ sectors that are largely informal. Based on a linear regression model, we report significant heterogeneity in earnings across sectors, which remain after controlling for aspects of human capital. We use a multinomial logit model to identify sector choice and show, allowing for selection, how returns to human capital differ across these sectors. We find that returns to basic education are important in largely informal sectors and that tertiary education is very important to access the higher paid sectors, but less important than in the lower paid sectors in increasing earnings once there. We then extend this analysis using quantile regression to show how returns differ across the distribution within sectors. Finally, we decompose the earnings gap across sectors and check how characteristics and return on these characteristics affect the cross-sector earnings gap. The earnings gap decomposition shows that workers of the lower paid sectors earn less, not only because they are less skill-endowed but also because they earn lower returns on their skills.
Dynamic Interfacial Tension Behavior of Alkyl Amino Sulfonate in Crude Oil-Brine System

Abstract The compatibility of surfactants, a series of alkyl amino sulfonate containing various the length of alkyl chain (dodecyl, tetradecyl, hexadecyl and octadecyl, developed in our laboratory), with formation water matching the Xinjiang Oil Field reservoir water and the dynamic interfacial tensions (DIT) behaviors between the crude oil and the formation water for a number of alkaline flooding systems were measured. These surfactants are found to be well compatible with formation water up to 0.10 g L−1 surfactant concentration, especially Dodec-AS and Tetradec-AS show a good compatibility with formation water over the full range of surfactant concentration investigated (0.01–0.20 g L−1). All surfactants exhibit the dynamic interfacial tension behavior, and can reach and maintain low interfacial tension at very low concentration. The time for reaching the equilibrium DIT (DITeq) is longer for surfactant with stronger lipophilicity, e.g. octadecyl-AS. It is interestingly found that the ratio value between DITeq and the tension at crude oil/reservoir water interface in the absence of surfactant is in the range of 10−4–10−3 mN m−1, accordingly based on which and the previous results, four surfactants individually or with other additives together may become potent candidates for enhanced oil recovery. Fortunately, the alkyl amino sulfonate combinational systems without alkali designed by our group can reduce the interfacial tension even to 10−4 mN m−1 at very low surfactant concentration. These surfactants or their systems have characteristic of “Green”, in addition to the excellent salt-tolerance and the less expensive cost for enhanced oil recovery, and therefore they are good oil-displacing reagents for enhanced oil recovery.
Preparation of MWNT/TiO2 Nanofluids and Study of its Thermal Conductivity and Stability

In this study, functionalized multi-walled carbon nanotubes using mixed acid treatment were synthesized using solvothermal method by TiCl4 as a precursor and the thermal conductivity enhancement of MWNT-TiO2 nanoflu i d s i n v a r i o u s t e m p e r a t u r e s w e r e compared. The treated nanotubes have been characterized using Fourier Transform Infrared Spectroscopy (FTIR). Hybrid materials were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that MWNTs are uniformly decorated with anatase nanocrystals. Temperature effects on thermal conductivity of MWNT-TiO2 nanofluids at different concentrations have been studied. The best result showed enhancement of thermal conductivity around 12.1% for the sample with 0.08 wt% of MWNT-TiO2 compared to distilled water at 36° C and 13. 71% at 52° C. Also, zeta potential of 0.02 wt% nanofluids and particle size distribution of nanoparticle were measured.
Patterns of SARS-CoV-2 exposure and mortality suggest endemic infections, in addition to space and population factors, shape dynamics across countries

Some countries have been crippled by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic while others have emerged with few infections and fatalities; the factors underscoring this macro-epidemiological variation is one of the mysteries of this global catastrophe. Variation in immune responses influence SARS-CoV-2 transmission and mortality, and factors shaping this variation at the country level, in addition to other socio-ecological drivers, may be important. Here, we construct spatially explicit Bayesian models that combine data on prevalence of endemic diseases and other socio-ecological characteristics to quantify patterns of confirmed deaths and cases across the globe before mass vaccination. We find that the prevalence of parasitic worms, human immunodeficiency virus and malaria play a surprisingly important role in predicting country-level SARS-CoV-2 patterns. When combined with factors such as population density, our models predict 63% (56-67) and 76% (69-81) of confirmed cases and deaths among countries, respectively. While our findings at this macro-scale are necessarily associative, they highlight a need for studies to consider factors, such as infection by other pathogens, on global SARS-CoV-2 dynamics. These relationships are vital for developing countries that already have the highest burden of endemic disease and are becoming the most affected by the SARS-CoV-2 pandemic.
Rare PSAP variants and possible interaction with GBA in REM sleep behavior disorder

PSAP encodes saposin C, the co-activator of glucocerebrosidase, encoded by GBA. Since GBA mutations are associated with idiopathic/isolated REM sleep behavior disorder (iRBD), a prodromal stage of synucleinopathy, we examined the role of PSAP mutations in iRBD. We fully sequenced PSAP and performed Optimized Sequence Kernel Association Test in 1,113 iRBD patients and 2,324 controls. We identified loss-of-function (LoF) mutations, which are very rare in PSAP, in three iRBD patients and none in controls (uncorrected p=0.018). Two variants were stop mutations, p.Gln260Ter p.Glu166Ter, and one was an in-frame deletion, p.332_333del. All three mutations have a deleterious effect on saposin C, based on in silico analysis. In addition, the two carriers of p.Glu166Ter and p.332_333del mutations also carried a GBA variant, p.Arg349Ter and p.Glu326Lys, respectively. The co-occurrence of these extremely rare PSAP LoF mutations in two (0.2%) GBA variant carriers in the iRBD cohort, is unlikely to occur by chance (estimated co-occurrence in the general population based on gnomAD data is 0.00035%). Although none of the three iRBD patients with PSAP LoF mutations have phenoconverted to an overt synucleinopathy at their last follow-up, all manifested initial signs suggestive of motor dysfunction, two were diagnosed with mild cognitive impairment and all showed prodromal clinical markers other than RBD. Their probability of prodromal PD, according to the Movement Disorder Society research criteria was 98% or more. These results suggest a possible role of PSAP variants in iRBD and potential genetic interaction with GBA, which requires additional studies.
A Colored Petri Net model for railway track maintenance with two-level inspection

Track fault may cause the derailment and it is one of the major contributors to railway maintenance costs. Gauge spread is one of the track faults. Maintenance and speed restriction should be taken according to the inspection results. Visual Inspection (VI) can only detect poor fastening and static gauge spread. Train Recording Vehicle (TRV) detects the loaded gauge spread. The inspection frequencies are required in Standards, but they should happen at a greater frequency if the recommendations are insufficient. Two inspection schemes are introduced for a railway section. One scheme considers that VI and TRV are periodic; another assumes that TRV interval depends on the number of identified defects. In this paper we propose a risk and maintenance model based on a hierarchical Colored Petri Net (CPN) for a railway section, since CPN is flexible enough to model the component deterioration process and the different inspection schemes. The CPN model considers not only the maintenance process for observed component states but also the accident scenarios. According to Monte Carlo simulation results, the model can be used to evaluate the inspection policies.
Fast Growth Synthesis of Silver Dendrite Crystals Assisted by Sulfate Ion and Its Application for Surface-Enhanced Raman Scattering

This paper reports the fast growth synthesis of silver (Ag) dendrite crystals on a copper (Cu) substrate assisted by sulfate (SO42–) ions based on a electroless galvanic displacement reaction between solid Cu and Ag(I) ion. The growth of Ag dendrites is succeeded by using an aqueous solution of Ag+ ion and a Cu foil. Interestingly, the morphology, apparent color, and growth rate of Ag dendrites on Cu foil using 2.5 mM Ag2SO4 aqueous solution are different from that of 5.0 mM AgNO3 aqueous solution even though they contain the same concentration of Ag+ ion. The growth rate of Ag dendrites is proved to be much accelerated for a solution of Ag+ ions with SO42–. The growth process can be readily observed under a microscope. The resultant Ag dendrites are characterized by scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. The effect of SO42– ion on the growth of Ag dendrites on Cu foil has been in.
Dye-Sensitized NiSx Catalyst Decorated on Graphene for Highly Efficient Reduction of Water to Hydrogen under Visible Light Irradiation

In this work, a highly active H2 evolution NiSx catalyst decorated on graphene (NiSx/G) nanohybrid was prepared by an in situ chemical deposition method, in which nickel ion was first adsorbed onto graphene and subsequently reacted with sulfide ion to yield the NiSx/G nanohybrid. The NiSx/G catalyst exhibited activity for hydrogen generation 2-fold higher than that of pristine NiSx under visible light irradiation. The highest quantum efficiency of 32.5% was reached at 430 nm when Eosin Y was used as a photosensitizer. In this system, graphene not only provided a large area and two-dimensional substrate for the confined growth of NiSx but also greatly enhanced the transfer of photoelectrons from excited Eosin Y to the NiSx cocatalyst because of its promotion of charge separation, leading to the great enhancement of photocatalytic hydrogen evolution.
Ju l 2 02 1 BOUNDED SECTIONAL CURVATURE AND ESSENTIAL MINIMAL VOLUME

For a closed smooth manifold M , we consider a closure of the set of metrics on M with sectional curvature bounded between −1 and 1. We introduce a variant of Gromov’s minimal volume, called essential minimal volume, defined as the infimum of the volume over this closure. We study metrics achieving the essential minimal volume, and prove estimates for negatively curved manifolds, Einstein 4-manifolds and complex surfaces with nonnegative Kodaira dimension.
Synthesis and Performance of Acyloxy-diene-Fe(CO)3 Complexes with Variable Chain Lengths as Enzyme-Triggered Carbon Monoxide-Releasing Molecules

Novel η4-acyloxy-cyclohexadiene-Fe(CO)3 complexes (with variable length of the acyloxy chain) were synthesized as potential enzyme-triggered carbon monoxide (CO)-releasing molecules (ET-CORMs). The molecular structure of two complexes was additionally confirmed by X-ray crystallography. The enzyme-triggered CO-releasing activity of the compounds was assessed under physiological conditions (37 °C, 0.1 M phosphate buffer, pH = 7.4) by headspace gas chromatography (GC) and additionally by means of a myoglobin assay (UV). The relative rate of CO release and the amount of liberated CO were found to depend on the length of the acyloxy chain and its position at the diene unit (outer or inner position). Some of the new ET-CORMs exhibited very good biological activity as assessed in different cellular assays (cytotoxicity, protective effect against hypothermia-associated cell damage, and inhibition of TNF-α-mediated VCAM-1 expression).
Fourier DF unit root test for R&D intensity of G7 countries

ABSTRACT According to the Schumpeterian endogenous growth theory, the efficacy of R&D is lowered by the proliferation of products. To be consistent with empirical data, the ratio between innovative activity and product variety (also called R&D intensity) must be stationary. From this perspective, our contribution investigates whether the R&D intensity series is stationary when structural breaks are considered. Our sample of G7 countries is examined over the period spanning from 1870 to 2016. Our results indicate that traditional unit root tests (ADF, DF-GLS and KPSS) conclude that the R&D intensity series are non-stationary, in contradiction with the Schumpeterian endogenous growth theory. The conclusions of these traditional unit root tests may be misleading, as they ignore the presence of structural breaks. Indeed, we use several types of Fourier Dickey-Fuller tests to consider the presence of structural breaks. In the Fourier Dickey-Fuller unit root tests using double frequency and fractional frequency, the R&D intensity is significantly stationary at least at the 5% level for Canada, France, Germany, Italy and Japan when a deterministic trend is included in the tests. Nevertheless, the R&D intensity is non-stationary for the US, even when we consider structural breaks.
Multifactor Keynesian models of the long-term interest rate

ABSTRACT This paper presents multifactor Keynesian models of the long-term interest rate. In recent years, there have been a proliferation of empirical studies based on the Keynesian approach to interest rate modelling. These studies evince the connection between the long-term interest rate and the short-term interest rate. However, standard multifactor models of the long-term interest rate in quantitative finance have not been yet incorporated Keynes’s insights about interest rate dynamics. Keynes’s insights are introduced in two different multifactor models of the long-term interest rate to illustrate how the long-term interest rate relates to the short-term interest rate, after controlling for the central bank’s policy rate, expected inflation, the central bank’s inflation target, volatility in financial markets, and Wiener processes.
Synthesis and fabrication of gelatin-based elastomeric hydrogels through cosolvent-induced polymer restructuring

Hydrogels have a wide range of applications in tissue engineering, drug delivery, device fabrication for biological studies and stretchable electronics. For biomedical applications, natural polymeric hydrogels have general advantages such as biodegradability and non-toxic by products as well as biocompatibility. However, applications of nature derived hydrogels have been severely limited by their poor mechanical properties. For example, most of the protein derived hydrogels do not exhibit high stretchability like methacrylated gelatin hydrogel has ∼11% failure strain when stretched. Moreover, protein derived elastomeric hydrogels that are fabricated from low molecular weight synthetic peptides require a laborious process of synthesis and purification. Biopolymers like gelatin, produced in bulk for pharma and the food industry can provide an alternative for the development of elastomeric hydrogels. Here, we report the synthesis of ureidopyrimidinone (Upy) functionalized gelatin and its fabrication into soft elastomeric hydrogels through supramolecular interactions that could exhibit high failure strain (318.73 ± 44.35%). The hydrogels were fabricated through a novel method involving co-solvent optimization and structural transformation with 70% water content. It is anticipated that the hydrogel fabrication method involves the formation of hydrophobic cores of ureidopyrimidinone groups inside the hydrogel which introduced elastomeric properties to the resulting hydrogel.
Enhanced Responsivity of Highly Spectrum-Selective Ultraviolet Photodetectors

Highly spectrum-selective photodetectors have been proposed and fabricated from the i-ZnO/n-ZnO structure. In this structure, the n-ZnO layer acts as a “filter” that filtrates out the short-wavelength photons to ensure the high spectrum selectivity of the photodetector. Meanwhile, the i-ZnO layer acts as a “multiplier” in which photogenerated carriers can be multiplied via an impact ionization process. In this way, photodetectors with their response width of only 9 nm have been obtained, and the responsivity of the photodetectors can reach 4.91 A/W at −5 V bias, corresponding to a quantum efficiency of 1600%. The results reported in this paper may provide a general route to high-performance, highly spectrum-selective photodetectors.
Determination of phase transformation surfaces around crack tip in shape memory alloys

In shape memory alloys (SMAs), a precise determination of phase transformation surfaces around the crack tip, is very important for the prediction of fracture parameters. In this work, the size of phase transformation region surrounding the tip of a edge crack is evaluated analytically. The purpose is restricted to tip without and with curvature loaded in mode I.
Thin-Layer Densitometry as an Alternative Tool in the Quantitative Evaluation of the Free Radical Scavenging Activity of Natural Antioxidants

An HPTLC system commonly used for chromatographic separations and analytical quality control has been utilized non-chromatographically as a screening tool for antioxidant activity in the 2,2- diphenyl-1-picrylhydrazyl (DPPH) free-radical scavenging assay. The accurate and precise capabilities for sample application and densitometric analysis of dry spots were applied to determine the 50% inhibition of DPPH (IC50) by a number of natural antioxidants at 530 nm. Concentration-response curves were generated from 3rd degree polynomial fitting of data acquired for each antioxidant at 4 concentration levels. The IC50 values ranged from 9.0 - 332.8 μM with quercetin being the most active and silybin the least active of the pure compounds. Three antioxidant extracts were also evaluated and grapeseed extract was the most active (IC50 8.3 μg/ml). The coefficients of variation for all IC50 values were around 5% which indicated method reproducibility and the suitability of the used system for the intended purpose. Based on its densitometric evaluation of dry spots, the described technique provides an alternative to the spectrophotometric evaluation of samples in solution.
Beads on a Chain (BoC) Phenylsilsesquioxane (SQ) Polymers via F– Catalyzed Rearrangements and ADMET or Reverse Heck Cross-coupling Reactions: Through Chain, Extended Conjugation in 3-D with Potential for Dendronization

In this paper, we assess the utility of complementary routes to silsesquioxane based compounds using F– catalyzed coupling to synthesize [vinylSiO1.5]xPhSiO1.5]10-x/12-x mixtures followed by copolymerization with divinylbenzene (via ADMET), or using reverse Heck coupling with 1,4-dibromobenzene and 4,4′-dibromo-stilbene to prepare lightly branched, nonlinear BOC systems. In another paper, we describe the use of Heck and Suzuki coupling to synthesize model conjugated p-R-stilbeneSQ BOCs starting from [p-IPh8SiO1.5]8 and coupling with divinylbenzene (DVB) and 1,4-diethynylbenzene (DEB) finding extended 3-D conjugation in the DEB polymers. We find that the reverse Heck coupling (where the linker contains the bromo moieties) works best for these systems giving BoC oligomers with Mn of ∼6 kDa, in which extended excited state conjugation is observed for 1,4-dibromobenzene linked systems through ∼50+ nm red shifts in the emission spectra compared with DVB linked systems and model compounds. We compare and contra.
Geographic variation in longevity and fecundity of the Asian corn borer,Ostrinia furnacalis Guenée(Lepidoptera:Crambidae)

The Asian corn borer Ostrinia furnacalis(Guenee) is a major pest of corn Zea mays(L.). It is widely distributed in China,encountering great diversity in climatic conditions among localities along the country′s north-south axis and exhibiting considerable diversity in life history among different geographic populations.Populations show clear differences in voltinism,critical day-lengths,postdiapause emergence times and cold tolerance.However,little is known about geographic variations in the species′ fecundity.In this study,specimens of O.furnacalis were collected from five different latitudes: Ledong,Hainan(LD,18.8°N,109.2°E);Nanchang,Jiangxi(NC,28.8°N,115.9°E);Taian,Shandong(TA,36.2°N,117.1°E);Langfang,Hebei(LF,39.5°N,116.7°E) and Haerbin,Heilongjiang(HEB,44.9°N,127.2°E). They were reared on an artificial diet under L16:D8 at 28 ℃ for three consecutive generations,and the relationships between longevity,pre-oviposition period,oviposition period,fecundity and collection latitude were analyzed.Significant differences among populations were found in longevity,pre-oviposition and oviposition period,and egg production.Longevity was positively correlated with latitude(10.20d,13.68d,13.90d,13.95d and 16.40d for females;8.35d,12.50d,13.62d,13.71d and 14.30d for males). The pre-oviposition period of the TA population was significantly shorter(2.00d) than that of other populations(LD: 2.75d,NC: 3.23d,LF: 3.33d,HEB: 3.25d). Oviposition period length tended to increase with latitude(7.45d,10.45d,11.90d,10.62d and 13.15d) and was significantly shorter in the LD population.Mean egg production per female was also positively correlated with latitude and was significantly lower in the LD population(351.55 eggs) than in the other populations(NC: 500.09 eggs,TA: 522.90 eggs,LF: 546.76 eggs,HEB: 577.95 eggs). The results show the presence of geographic variation in the reproductive tactics of O.furnacalis and reveal significantly higher fecundity in the northern than in the southern populations,suggesting a possible reason for the generally higher losses of corn to Asian corn borer damage in northern than in southern China.
Optical Forces from Periodic Adiabatic Rapid Passage Sequences on Metastable Helium Atoms

of the Dissertation Optical Forces from Periodic Adiabatic Rapid Passage Sequences on Metastable Helium Atoms by Daniel Thomas Stack Doctor of Philosophy in Physics Stony Brook University 2012 Over the past 30 years, optical manipulation of neutral atoms has been primarily performed with a monochromatic laser beam. The simplest tool for the control of atomic motion is the radiative force exerted by a monochromatic laser on a twolevel atom. The radiative force arises from absorption followed by spontaneous emission, and its magnitude is limited by the atom’s excited state lifetime. The coherent momentum exchanges between light fields and atoms can be exploited to produce long-range optical forces much greater than the radiative force through the use of absorption-stimulated emission processes. Adiabatic Rapid Passage (ARP) is a long-existing method to invert the population of a two-level nuclear spin system. Its extension to the optical domain iii necessitates a frequency chirped light pulse to interact with a two-level atom via the dipole interaction. I will first present a numerical study of the properties of optical forces on moving atoms derived from purely stimulated processes produced by multiple ARP sequences. This will be followed by experimental observations of long-range ARP forces much larger than the radiative force in metastable helium. Sequences of properly timed laser pulses may be used for rapid deceleration of neutral atomic (or molecular) beams.