Widening Of Gap Research Articles

Exploring the stability and aromaticity of rare earth doped tin cluster MSn16- (M = Sc, Y, La).

Rare earth elements have high chemical reactivity, and doping them into semiconductor clusters can induce novel physicochemical properties. The study of the physicochemical mechanisms of interactions between rare earth and tin atoms will enhance our understanding of rare earth functional materials from a microscopic perspective. Hence, the structure, electronic characteristics, stability, and aromaticity of endohedral cages MSn16- (M = Sc, Y, La) have been investigated using a combination of the hybrid PBE0 functional, stochastic kicking, and artificial bee colony global search technology. By comparing the simulated results with experimental photoelectron spectra, it is determined that the most stable structure of these clusters is the Frank-Kasper polyhedron. The doping of atoms has a minimal influence on density of states of the pure tin system, except for causing a widening of the energy gap. Various methods such as ab initio molecular dynamics simulations, the spherical jellium model, adaptive natural density partitioning, localized orbital locator, and electron density difference are employed to analyze the stability of these clusters. The aromaticity of the clusters is examined using iso-chemical shielding surfaces and the gauge-including magnetically induced currents. This study demonstrates that the stability and aromaticity of a tin cage can be systematically adjusted through doping.

Evaluation of Testicular Function and Structural Changes of Wistar Rats Following Antiretroviral Exposure: Protective Role of Cyperus Esculentus.

Long-term antiretroviral drug toxicity may exacerbate the impact of HAART-Cyperus esculentus (C. esculentus) interactions on testicular function in HIV-infected individuals. This study examined the ability of C. esculentus plants to treat testicular dysfunction, which is thought to be a probable side effect of antiretroviral toxicity. Adult Wistar male rats weighing 90-110 g were divided into six groups and administered the prescribed treatments. In addition to testicular histology and stereological parameters, testosterone levels, follicle-stimulating hormone levels, antioxidant markers, malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione levels were also evaluated. The adverse consequences of highly active antiretroviral therapy (HAART) include considerable loss of germ cells, enlargement of the tubular lumen, widening of interstitial gaps, and severe hypocellularity. Compared to the other treatment groups, MDA levels dramatically increased, whereas GSH and antioxidant enzyme (SOD) levels significantly decreased. Testicular architecture was largely conserved after treatment with C. esculentus, with a notable increase in the cellular densities of germinal and interstitial cells and a notable decrease in the tubular lumen. Vacuolation, architectural malformations, and hypoplastic changes were reduced. Significant improvements were also observed in C. esculentus in terms of elevated antioxidant SOD and GSH levels and decreased MDA levels. C. esculentus reduced architectural distortions and testicular dysfunction caused by HAART, and improved testicular morphology. Further exploration of these pathways is required.

Rare earth-based oxides double perovskites A2NiMnO6 (A= La and gd): Applications in magneto-caloric, photo-catalytic and thermoelectric devices

In this paper, we have conducted theoretical work on rare earth-based double perovskites namely, La2NiMnO6 and Gd2NiMnO6, using generalized gradient approximation (GGA) and GGA + U formulations within the full potential linearized augmented plane wave (FP-LAPW) method. It is revealed that using GGA + U computations instead of the conventional GGA method results in a reasonable widening of the band gaps and best fit with the previously explored experimental data with U = 1.5 eV. Further, the band gap values are increased with increasing the U values for the 3d states of Ni and Mn. Moreover, we found that these materials show high magnetic moment, high absorption in the visible and ultraviolet region, and high figure of merit (nearly one for Gd2NiMnO6 at room temperature), hence show their potential in multiple applications such as magneto-caloric, photo-catalytic, solar energy, and thermoelectric devices.

A re-examination of the influence of human capital on urban-rural income gap in China: College enrollment expansion, digital economy and spatial spillover

In the context of the era of common prosperity, this paper seeks to explore the influence of human capital on the urban-rural income gap in China. To accomplish this, this paper utilizes panel data encompassing 31 provincial-level administrative regions spanning the years 2000 to 2019. Employing a combination of econometric techniques, including 2SLS, Difference-in-difference models, moderating effects models, and the spatial Durbin model, this paper investigates various facets of human capital and its impact on the urban-rural income gap. The key findings of this paper are as follows: (1) The relationship between human capital and the urban-rural income gap exhibits a U-shaped pattern. (2) The college enrollment expansion policy leads to the widening of the urban-rural income gap in China driven by factors related to the scale, quality, and inequality within higher education. (3) The digital economy plays a positive moderating role in the U-shaped relationship between human capital and the urban-rural income gap. (4) Human capital's impact on the urban-rural income gap demonstrates a significant spatial correlation, displaying a U-shaped spatial spillover effect. Drawing from the aforementioned findings, this paper offers valuable policy implications to guide policymakers in their efforts to foster the attainment of common prosperity.

Electric field tuning of multistate and nonvolatile resistance variation in amorphous Fe75Si25/PMN-0.3PT (0 0 1) heterostructures

The multistate resistance states in the amorphous Fe75Si25/0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 (PMN − 0.3PT) (001) heterostructure were modulated by electric fields (E). Based on the in-plane nonvolatile stress changes associated with ferroelectric domain switching in PMN-0.3PT, the widening and narrowing of surface gaps, and the fact that magnetism generally tracks the strain variation in amorphous Fe75Si25 films, the distinct four-state and nonvolatile resistance tuning near the coercive E-field are observed. Then, combining the converse magnetoelectric coupling and magnetoresistive effect, we quantify the coaction effect and equivalence relation between the E-field and magnetic fields (H) on the resistance modification. Meanwhile, another four-state resistance is obtained under the coaction of the E-fields and H-fields. All eight resistive states exhibit excellent E-field switchable behavior and stability performance at room temperature. These results provide a promising approach for exploring and designing multistate and multifield controlled spintronic memory devices.

Arthroscopic assessment for lateral collateral ligament complex deficiency of the elbow: a cadaveric study.

To evaluate whether elbow instability due to lateral collateral ligament complex injury can be assessed reliably through arthroscopy. Eight fresh human cadaveric elbows were placed in a simulated lateral decubitus position. The radiocapitellar joint (RCJ) gap and ulnohumeral joint (UHJ) gap (mm) were measured with different sizes of probes from the posterolateral viewing portal. The elbow was 90 degrees flexed with neutral forearm rotation for RCJ gap measurement and 30 degrees flexed with full supination for UHJ gap measurement. Sequential testing was performed from Stage 0 to Stage 3 (Stage 0: intact; Stage 1: the release of the anterior 1/3 LCL complex; Stage 2: the release of the anterior two thirds of the LCL complex; and Stage 3: the release of the entire LCL complex) on each specimen. The mean gap of RCJ and lateral UHJ was used for the comparison between stages with the intact elbow. The mean RCJ gap distance in Stage 2 and Stage 3 was significantly increased compared to that in Stage 0 (Stage 0 vs. Stage 2: P = .008; Stage 0 vs. Stage 3: P = .010). The mean UHJ gap distance of Stage 1, Stage 2, and Stage 3 was significantly increased compared to that in Stage 0 (Stage 0 vs. Stage 1: P = 0.025; Stage 0 vs. Stage 2: P = .010; Stage 0 vs. Stage 3: P = .011). In contrast, the release of the anterior 1/3 of the LCL complex (Stage 1) was not significantly increased compared to the mean joint gap distance of RCJ (P = .157). Arthroscopic measurement of joint gap widening in RCJ and UHJ is a reliable assessment method to detect LCL complex deficiency that involves the anterior two thirds or more.

Effect of dehydrogenation on optical constants of silicon nitride thin films

This study presents annealing experiments conducted on near-stoichiometric hydrogenated amorphous silicon nitride (a-SiNx:H) thin films deposited via Plasma Enhanced Chemical Vapor Deposition. The heat treatment was carried out under an inert atmosphere within a temperature range of 400–1000 °C, with increments of 100 °C. After each annealing step, a-SiNx:H films were subjected to characterization using visible and FTIR spectroscopies, evaluating their optical and structural properties, as well as hydrogen concentration. The infrared analysis reveals a significant reduction in Si–H bond concentration within the temperature range of 400–700 °C, becoming virtually undetectable at higher annealing temperatures. Conversely, the N–H bond concentration primarily decreases at elevated temperatures, persisting at 23% of its initial value at 1000 °C. Optical constants were determined from transmittance spectra using a dispersion model that combines two unbounded Tauc-Lorentz oscillators. The refractive index experiences an increase up to 600 °C due to material densification, followed by a decrease at higher temperatures attributed to optical gap widening. Dispersion curves of the extinction coefficient reveal a wide sub-gap absorption band, which vanishes after a 900 °C annealing step, rendering the material suitable for waveguide applications.

Assessing the impact of future climate scenarios on crop water requirements and agricultural water supply across different climatic zones of Pakistan

This study investigates the potential impacts of future climate change on crop water requirements (CWR) in different climatic zones of Pakistan and the subsequent implications for agricultural water demand and supply. Using the latest CMIP6 climate projections, we focused on Rabi and Kharif crop seasons, which are crucial for the growth of major crops in Pakistan. An empirical climate-crop and a hydrological model based on the Budyko theory were modified and forced to project future CWR changes and the potential widening of the water demand-supply gap until 2,100. Our results indicate a significant rise in mean annual CWR across all zones and emissions scenarios, with increasing rates at 2.30–2.57 mm/yr under SSP585 and 1.0–1.26 mm/yr under SSP245. Both Rabi and Kharif seasons show rising CWR, notably more under SSP585 (Kharif: 8%–14%, Rabi: 12%–15%) than SSP245 (Kharif: 4%–7%, Rabi: 6%–8%). The demand-supply gap is expected to grow notably, with arid and semi-arid zones being the most affected. Compared to 2015–2025, by 2091–2,100, the gap increased by 7%–15% (SSP245) and 15%–28% (SSP585) for Kharif and 7%–13% (SSP245) and 13%–32% (SSP585) for Rabi. To address these challenges, we recommend strategies like enhancing irrigation efficiency, adjusting crop patterns, and developing heat-resilient crops. Our insights aim to inform policy decisions on agriculture and water management in Pakistan under future climate change.

Physico-chemical characterization and photocatalytic activity assessment under UV-A and visible-light irradiation of iron-doped TiO2 nanoparticles

In this work, undoped TiO2 and Fe-doped TiO2 materials as photocatalysts for water remediation, were synthesized using wet chemical methods (sol–gel + precipitation). Their crystalline structure, optical and morphological properties were explored using X-ray diffraction (XRD), Fourier-transform infrared (FTIR) and Raman spectroscopies, UV–vis diffuse reflectance (DRS) and photoluminescence (PL) spectroscopy, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy coupled to the energy dispersive X-Ray spectroscopy (SEM-EDS). The photocatalytic performance of the synthesized materials was assessed through the degradation of methyl orange (MO) under UV-A and visible-light irradiations. The structural study showed the existence of predominate anatase phase in all synthesized nanomaterials. The optical study showed a widening of the band gap for Fe-doped TiO2 materials and revealed a decrease in charge carrier’s recombination for all Fe-doped TiO2 nanomaterials compared to undoped TiO2. The morphological study confirmed the nanometric scale of the materials particles. The photocatalytic experiments revealed an enhanced photocatalytic activity of 0.5 %wt Fe-doped TiO2, only under UV-A light, compared to the rest of the prepared nanomaterials. The enhanced photocatalytic activity has been attributed to the efficient charge separation of electrons and holes.

Characterization and modeling of a-Si:H-based n-i-p photodiodes with protocrystalline silicon p-layers

This article reports on blue-enhanced a-Si:H-based n-i-p photodiodes with protocrystalline silicon (pc-Si:H) p-layers by plasma-enhanced chemical vapor deposition. Microstructure of p-layers was studied by Raman spectroscopy. An optical model has been developed to analyze the device performance. The Transfer Matrix Method was applied to simulate light propagation in the glass/Cr/n-i-p/ZnO:Al stack, while modified Tauc-Lorentz model including the Urbach tail was used to obtain the dispersive optical constants for each semiconductor layer. Two photodiodes with a-Si:H and pc-Si:H p-layers were fabricated, characterized, and modeled for comparison. The deduced optical gaps are 1.8 and 2.33 eV for p-type a-Si:H and pc-Si:H, respectively. Observed band gap widening is the quantum confinement effect due to Si nanocrystals in pc-Si:H. Modeling reveals that incorporation of pc-Si:H leads to a significant reduction of absorption and reflection losses. The optimized heterojunction photodiode exhibits a quantum efficiency up to 92% at 510 nm wavelength. The achieved quantum efficiency of 66% at 400 nm wavelength almost triples that for the homojunction photodiode.

Regional differences and evolution trends of China’s industrial green transformation

Green and low-carbon development is the direction of the current technological revolution and industrial transformation, while China is still in the historical stage of deep industrialization and has yet to completely break away from the high-input, high-consumption, and high-emission development method, and is still facing serious challenges in terms of improving the efficiency of resource utilization and reducing pollution emissions. To effectively promote China’s industrial green transformation, it is necessary to accurately grasp its development connotations and scientifically realize the measurement of industrial green transformation. Therefore, this paper measures the efficiency of China’s industrial green transformation, based on the directional distance function and the Global Malmquist-Luenberger (GML) index, to portray its distribution dynamics, regional differences and further identify its growth drivers. The results found that the overall efficiency of China’s industrial green transformation has been steadily increasing, and that the regional pattern is characterized by northwestern, northeastern, central, eastern and southwestern regions, in that order. The Markov chain estimates show that industrial green transformation efficiency is most likely to remain in its original state, with probabilities of 88.31%, 63.54%, 42.86%, and 75.61% for low, medium-low, medium-high, and high levels respectively, but also has a jump shift characteristic, with a certain possibility of falling back from the high-efficiency state to the low state. Dagum Gini coefficient estimation results show that differences between groups in the five major regions are the main source of the widening differences in the overall industrial green transformation, with the contribution remaining at around 60%. Further research suggests that economic growth, technological progress, foreign trade, and foreign direct investment (FDI) may lead to a widening of the efficiency gap in industrial green transformation, while the industrial structure and outward foreign direct investment (OFDI) help to reduce spatial differences to some extent. Based on the above conclusions, this paper proposes some countermeasures to promote the overall improvement and coordinated development of China’s industrial green transformation.

Impact of alloying iron pyrite by ruthenium on its band gap values and its insight to photovoltaic performance

In pursuit of augmenting the band gap value of thin films composed of FeS2 Pyrite, our study encompasses both theoretical and experimental investigations. Specifically, we sought to delve into the electronic and optical properties of FeS2 alloyed with ruthenium, denoted as Fe1−xRuxS2, where x varied across a range of values (x = 0.3966, 0.1586, 0.0496, 0.0347, 0.0106, and 0.00). Our theoretical analysis employed the Linear Muffin-Tin Orbital technique within the Atomic-Sphere approximation (LMTO-ASA) framework, focusing on the density of states. In parallel, our experimental samples were fabricated via a cost-effective and straightforward method involving the sulfuration of amorphous iron oxide thin films, which were deposited through spray pyrolysis of an aqueous solution containing FeCl3.6H2O onto heated glass substrates at 400 °C. This comprehensive investigation sheds light on the influence of alloying on the atomic structure and the optical characteristics of RuxFe1−xS2 samples. Utilizing X-ray diffraction (XRD) and optical characterizations, we observed a notable widening of the band gap of FeS2, ranging from 0.90508 to 1.38 eV, when approximately 1.06% of the Fe atoms were replaced with ruthenium atoms (x = 0.0106 concentration of Ru). This finding holds significant implications for the potential applications of our samples in photovoltaic technologies.

ROLE OF HUMAN CAPITAL, INCOME INEQUALITY AND RENEWABLE ENERGY CONSUMPTION ON CO2 MITIGATION IN MALAYSIA

The present research endeavours to investigate the interconnection among human capital, income inequality, renewable energy consumption, economic growth, and pollution. The ultimate objective is to identify effective policy approaches by uncovering empirical findings. This study employs the innovative approach of dynamic ordinary least square (DOLS) to examine data spanning from 1980 to 2018. In order to evaluate the accuracy of the DOLS estimation, we utilise the fully modified ordinary least square (FMOLS) and canonical correlation regression (CCR) techniques. In order to comprehensively investigate the association between the chosen variables, a paired Granger causality analysis was employed. Findings of this study show that using renewable energy enhances Malaysia's environmental quality, while economic growth, income inequality, and human capital all cause environmental deterioration. Therefore, it is possible that Malaysia could achieve its goal of reducing CO2 emissions and meeting its obligations under the Paris Agreement if it were to successfully adopt policy initiatives to develop human capital, increase the use of renewable energy sources, achieve a low-carbon economy, and reduce the income disparity. The research presents several new findings. The authors show that economic growth is one of the drivers of renewable energy use because it provides inputs for the development of renewable energy technology and infrastructure. But if there is pollution as a result of rapid economic growth, it will also negatively impact worker productivity. As a result, the poor get poorer, and the income inequality gap widens. This will obstruct both economic advancement and government efforts to promote the creation of renewable energy sources.

Research on the Deconstruction of Distress Dimensions and the Construction of Relief Strategies for Urban Poverty in China

Since Chinas reform and growth, the continuous development of the social economy and the constant improvement of peoples living standards have been the mainstream of societys development. However, with the foundation and improvement of Chinas market economy and the ongoing promotion of Chinas urbanization process, the number of impoverished people among urban residents is increasing, and the gap between the rich and the poor is widening. This paper uses Literature research, data collection and analysis, and MPI to explore the dimensional deconstruction of urban poverty and find that the existence and widening of the income gap is the main cause of structural poverty in the country. Also, the employment dimension has the greatest impact on multidimensional urban poverty. The employment dimension has the greatest impact, followed by the education dimension. These problems can be solved by strengthening income adjustment measures to narrow the income gap, ensuring labor force employment, and improving the social security system. The paper can better help solve the problem of urban poverty and reduce the number of urban low-income families.

Schottky junction based solar cell behavior of trichome hierarchical SnO2 nano-structures

Hydrothermally grown SnO2 hierarchical trichome nano-flowers (T-NFLs) have been examined for their device performance compared to nano-flakes (NFs), in part to meet the growing need for metal-oxide based solar cells. The structural analyses reveal superior lattice strain and free energy in the tetragonal phase of the T-NFLs over NFs. The band gap widening and oxygen defect-dominated luminescence in the visible range are observed from photoluminescence measurements. Compared to NFs, the Schottky current-voltage characteristics of the T-NFLs show improved Schottky barrier height (0.82 eV) with an ideality factor of 3.52 under dark and better solar cell properties with a conversion efficiency of 1.78 ± 0.03% under 1 sun illumination. The observed high open-circuit voltage of 1.56 V resulted from the decrement rate of carrier recombination, making the transparent metal oxide nano-material SnO2 T-NFLs suitable for solar cells and fast electronic applications.

Room temperature ferromagnetism, optical band gap widening in Mg-doped ZnO compounds for spintronics applications

In the present research work, a conventional solid-state synthesis approach was used to synthesize the polycrystalline compound of Mg-doped ZnO (Zn1-xMgxO with x = 0–0.12). The XRD analysis reveals that Mg-doped compounds have been crystallized in a single hexagonal phase. The SEM analysis revealed that these compounds are constituted with microscopic spherical particles with a size range of 1–3 μm. Raman scattering spectra of these compounds displayed a blue-shift of the Raman active E2 (low) mode attributed to the vibration of zinc atom in wurtzite ZnO, indicating Mg ions were substituted successfully into the ZnO lattice. Optical measurements revealed that the optical band gap enhanced from 3.12 to 3.17 eV, while the transmittance value improved from 87% to 96% as the Mg doping percentage is increased. The magnetization (M) versus applied field (H) measurements, done at 300 K reveals that the undoped ZnO compound exhibits weak ferromagnetic behavior, whereas all Mg-doped ZnO compounds show a strong ferromagnetism with coercivity ranging between 85Oe≤Hc≤1482Oe, and with the highest saturation magnetization of 0.255 emu/gm for 12% Mg-doped sample.

Novel functionalized of ZnO with Sm3+, La3+, and Sr2+/ZnO single and tri-doped nanomaterials for photocatalytic degradation: synthesis, DFT, kinetics

AbstractPure zinc oxide, single-doped zinc oxide as 2 wt% of Lanthanum as (La DZ NPs), 2 wt% of Samarium (Sm DZ NPs), and 2 wt% of Strontium as (Sr DZ NPs), and tri-doped (Sm, La, Sr, T DZ NPs) were synthesized with a hydrothermal method. Additionally, these nanomaterials are used as an effective photocatalytic for the degradation of Reactive Red 43. These nanomaterials’ optical, particle size distribution, structural properties, and morphology were analyzed using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), ultraviolet (UV) light, photoluminescence (PL), scanning electron microscopy (SEM) and energy-dispersive X-ray (XPS), transmission electron microscopy (TEM), and the point of zero charges (pHpzc). Molecular modeling simulation was calculated using density functional theory (DFT) to confirm some characterization. Moreover, these studies showed the crystal structure parameters changed with doped nanomaterials, and the experimental band gap fit theoretical calculation and demonstrated the reason for the widening of the band gap. An enhancement in the surface area of Sr DZ NPs recorded high value (SBET = 37.43 m2/g) indicated that it can be used as an efficient photocatalyst, where Sr DZ NPs showed the best photodegradation % of Reactive Red 43 dye with 93.43% compared to PZ (72.88%), La DZ NPs (52.54 3%), Sm DZ NPs (31.99%), and La, Sm, Sr T DZ NPs (20.55%). Furthermore, the pseudo-first-order kinetic model better fits the R2 values. Finally, the mechanism of degradation has been related to electronic configuration. In addition, the recyclability showed stability of nanomaterials under UV irradiation. Graphical abstract

The Causes and Effects of Poverty in Somalia: A Case Study of Guriceel District, Galmudug State, Somalia

This study focused on the causes and effects of poverty in Guriceel district, Galmudug state, Somalia. The aim of the study was to examine the causes and effects of poverty in Guriceel district, Galmudug state, Somalia. The study adopted a descriptive survey and targeted 500 people in Guriceel district. A sample of 126 respondents of the target population was considered by use of stratified purposive sampling technique. The primary data was collected through the use of closed-ended questionnaires and secondary data was obtained from literatures reviewed from the published documents by various scholars to supplement the primary data. The key findings of the study were that there are many causes of poverty in Guriceel district which they include: continuous civil war in Somalia is hindering economic activities of the people which is subjecting them into poverty, high level of corruption among civil servants, the existence of weak rule of law and poor governance leading to poor and ineffective service delivery in the district is causing of poverty in the district, high level of unemployment leading to low income generation by the residents in the district is causing poverty, poor access to affordable and quality health care in the district is causing poverty, high reproductive rate in the district is causing poverty in the district, dangerous climate change resulting into continuous drought is causing poverty in the district and lastly poor planning and distribution of social and economic services in the district is causing poverty in the district. And the main effects of poverty in Guriceel district entail: increase in the risk of people becoming infected with chronic illness, made people to live in dilapidated housing, increase of the death rate in the district, high risk of education underachievement for children from poor families, increase of mental health problems among poor people, high risk of education underachievement for children from poor families, increase of mental health problems among poor people, widening of gender inequality gap, increase in the rate of malnutrition among children from poor families who have got inadequate nutrition, reduction of life expectancy level among poor people and lastly poverty increase in crime rate like theft in Guriceel district. The study recommends that Federal Government of Somalia should provide enough and quality social services, establish more vocational training schools, create more jobs for the jobless youth, empower women, promote and practise of effective accountability and transparency in the public service to curb corruption, provide quality and affordable health services, formulate new policy on new on friendly youth-employment, reform the education curriculum and of more micro-finance institutions in all sub-districts in Somalia to provide loan to poor people.

Green productivity divergence and factor endowments: Evidence from the Yellow River Basin, China

Using panel data for the Yellow River Basin (YRB) of China from 2006 to 2017, we investigate cross-city conventional total factor productivity (TFP) and green TFP convergence, and the moderating effects of relative factor endowments on TFP growth. Allowing for cross-city and cross-time variation in the production function, we estimate TFP across cities using a nonlinear varying coefficient model, and decompose it into various input-embedded and input-free productivity components based on the new growth accounting, covering all growth-driving channels. This paper then employs a conditional convergence framework to examine whether convergence occurs, through which channels, and the effects of relative factor endowments on them. Empirical results show that lagging cities fail to achieve TFP catch-up, and that the divergence of capital-embedded and labor-embedded productivity instead triggers a widening of the cross-city TFP gap. Part of the cause of this increase in these gaps is that cities with relatively high capital deepening and capital-to-energy ratio are experiencing rapid TFP growth by driving the quality of capital and labor. Nor have these effects been altered in examining environmentally constrained or green TFP convergence.

Adolescent development and the math gender gap

This paper investigates the determinants of the gap between girls and boys in mathematics performance (the ‘math gap’). We are particularly interested in the role played by pubertal development in explaining the widening of the math gap over adolescence. We estimate rich production function models of math skills, using data from the 1958 British National Child Development Study (NCDS), a longitudinal survey of all British children born in a single week in March 1958 which contains unique information on pubertal development and educational outcomes. Using (cumulative) value-added models, we show that the impact of puberty varies by the age and gender of the child, and that this heterogeneity can explain about two thirds of the math gap that emerges between the ages of 11 and 16. We find also that the widening of the math gap during adolescence is driven by markers of pubertal development which are publicly evident, rather than by markers which are only privately evident; and that the relationship between puberty and math scores is strongly associated with children's self-perceived ability in math. Taken together, these results suggest that the mechanisms underlying the relationship between pubertal development and the math gender gap are socially rather than biologically driven.