This paper investigates the permanent effect on total factor productivity (TFP) of temporary shocks. We estimate a structural vector autoregression to test the predictions of endogenous growth models over the business cycle. According to theory, the stock of technological knowledge promotes its flow as researchers “stand on the shoulders of giants.” Therefore, if R&D investment is pro-cyclical—as data show and theory predicts—a recession leads to a temporary deviation of the R&D level from its trend, thus reducing new knowledge creation. The lost technological advancements cause the economy to follow a parallel but permanently lower growth path. Our findings align with the primary theoretical prediction. Quantitatively, the US economy forgoes approximately 1.3% in TFP following an increase in cyclical unemployment that peaks at 1 percentage point above the mean. The historical variance decomposition shows a strong positive effect during the boom of the late 1960s and strong negative effects around the Volcker disinflation period and the Great Recession. Finally, we estimate the effects on R&D of a TFP shock to differentiate between different explanations on how the R&D pro-cyclicality arises. Our results align with models where financial frictions or nominal rigidities drive it.

We report the lattice parameters and cell volume for cristobalite powder added at 35 wt% to Ba-Al-Silicate glass (CGI930) as reflowed bulk glass bars where the embedded cristobalite phase is constrained within the glass matrix. Analysis confirms that the room temperature lattice parameters and cell volume obtained for the bulk glass–ceramic are larger compared with single-phase cristobalite powders. The increased volume of the cristobalite phase in a glass matrix is driven by tensile stresses developed at the interface between the cristobalite and matrix glass phase, and this stress impacts the phase transition temperature and thermal hysteresis of the cristobalite phase. In situ high-temperature measurements confirm that the tetragonal to cubic α–β phase transformation of the cristobalite phase within the glass matrix is ~195 °C with complete suppression of hysteresis behavior. In contrast, bulk glass–ceramic material ground to a powder form displays the expected thermal hysteresis behavior and more comparable phase transition temperatures of 245 °C on heating and 220 °C on cooling. Isothermal holds at varying temperatures above or near the α–β phase transition suggest that the cristobalite phase does not undergo significant relaxation within the matrix phase to reduce accumulated stress imposed by the constraining matrix glassy phase.

Samples of Na-saturated, Upton montmorillonite were prepared with different contents of water (H2O or D2O) by: (1) adsorption of water from the vapor phase at a specific value of p/p°, the relative humidity, (2) adsorption of water from the vapor phase at p/p° = 1.0 followed by desorption of the water into the vapor phase at a specific p/p° < 1.0, and (3) adsorption of water from the liquid phase followed by desorption of the water into the vapor phase at a specific p/p° < 1.0. Water adsorbed initially from the vapor phase was called V-adsorbed water, and water adsorbed initially from the liquid phase was called L-adsorbed water. The water contents of these samples were determined by gravimetric analysis, the c-axis spacings by X-ray powder diffraction, the O-D stretching frequencies by IR spectroscopy, and the heats of immersion by differential microcalorimetry. No difference was found between V-adsorbed and L-adsorbed water; however, if the final water content was established by adsorption, the system was in a different state than if the final water content was established by desorption. In particular, hysteresis was observed in the following properties: the relative humidity of the adsorbed water, the O-D stretching frequency in this water, and the degree of order in the stacking of the clay layers. The only property that did not exhibit hysteresis was the heat of immersion. Apparently, hysteresis occurred because the orderliness of the system was not reversible, and, thus, any property that depended on orderliness was hysteretic.

An environmental infrared microbalance (EIRM) cell was used to study H2O sorption on two montmorillonite samples as a function of water content and type of exchangeable cation. The vibrational spectra showed that H2O sorbed to the clay at low-water content was strongly influenced by the exchangeable cation and by the close proximity to the clay surface. At water contents <6 H20 molecules per exchangeable cation, the H-O-H bending mode of H2O (v2 mode) shifts to a lower frequency and is characterized by an increase in molar absorptivity. In contrast, the positions of the asymmetric and symmetric OH-stretching modes of sorbed water (v1 and v3 modes) shift to higher energies. These observations indicate that H2O molecules sorbed to the clay surface at low-water content are less hydrogen bonded than in bulk H2O. In addition, the vibrational-stretching and bending bands of the structural OH groups of the 2:1 layer are also strongly influenced by H2O content and type of exchangeable cation. By using the EIRM cell, the molar absorptivities of the structural OH-bending vibrations were measured as a function of H2O content. The position and molar absorptivity of the structural OH-bending bands at 920, 883, and 840 cm-1 are strongly influenced by H2O content and type of exchangeable cation. The molar absorptivity of the 920-cm-1 band, which is assigned to the AlAlOH group, decreased strongly at low-H2O content. This reduction in intensity is assigned to a dehydration-induced change in orientation of the structural OH groups resulting from the penetration of H2O molecules into siloxane ditrigonal cavities that are not associated with a net negative charge from isomorphous substitutions.

The binary exchange of cations on clays and soils is generally regarded as a thermodynamically reversible process. The literature on soil chemistry and geochemistry, however, abounds with reports on cation exchange reactions that appear to have only limited reversibility, i.e., that exhibit hysteresis. A satisfactory explanation of this phenomenon is still lacking, even though a number of mechanisms have been advocated, e.g., charge or site heterogeneity at the surface, differential hydration of cations, dehydration of the exchanger, crystalline swelling hysteresis, and inaccessibility of sites caused by domain or quasi-crystal formation. In the present article, the relevant literature is reviewed and analyzed critically. On the basis of available evidence, it is shown that exchangeable cations can be classified into three groups, defined in such a way that hysteresis has, in the literature, generally not been observed when exchange reactions involved cations belonging to the same group, but has often been found when the reactions involved cations from different groups. Furthermore, it is argued that none of the five mechanisms mentioned can, in and of itself, account fully for the observed exchange hysteresis. A conceptual model is proposed that combines elements of these five mechanisms and is able to describe, at least qualitatively, the effects of factors such as clay type, electrolyte concentration, and extent of dehydration.

Adsorption-desorption of Cd to Ca montmorillonite (SAz-1) was studied at concentrations ranging from 44.5 to 266.8 μM. An adsorption model was employed in the analysis of the data. The procedure consists of solving the electrostatic Gouy-Chapman equations and calculating adsorbed amounts of the cations as the sum of the cations residing in the double-layer region, and the cations chemically bound to the surface, in a closed system. The model also accounts explicitly for cation complexation in solution. The model yields good predictions for the adsorbed amounts of Cd, Ca and Mg, by employing binding coefficients from previous studies for the divalent cations and for Na, K and CdCl+. The model calculations also yield good predictions for the apparent hysteresis observed in the adsorbed amounts of Cd after each of 3 cycles of desorption. The apparent hysteresis is explained by the reduction in the total concentrations of Ca and Mg in desorption cycles, and the corresponding increase in the magnitude of the surface potential. Our estimates indicate that adsorption of Cd is mostly to planar, rather than edge sites of the clay mineral.

Sorption of the herbicide isoxaflutole and its main degradate, diketonitrile (DKN), to natural clays, SAz-1, SWy-2 and SHCa-1, and the organoclay derivatives (octadecylammonium (ODA) and hexadecyltrimethylammonium (HDTMA)) of these clays was investigated. Isoxaflutole hydrolysis to DKN was too rapid in aqueous solutions with organoclays to characterize sorption. No measurable DKN sorption was observed for the natural clays. Sorption of DKN was greater on organoclays with an interlayer paraffin-like complex that were prepared from the high-charge SAz-1 clay than on organoclays with a bilayer or monolayer interlayer complex prepared using lower-charge SWy-2 or SHCa-1 clays. Desorption isotherms indicated that sorption was irreversible. For SAz-1 with HDTMA at ∼100% of the clay CEC, the d001 values suggest that DKN enters the interlamellar space of the organoclay and dissociates into the anion. The DKN anion forms a very stable chelate complex with the residual cations and/or partially-coordinated structural cations. This strong interaction supports the irreversibility of the sorptive process.

In Chen and Liang previous work, a model, together with its well-posedness, was established for credit rating migrations with different upgrade and downgrade thresholds (i.e. a buffer zone, also called dead band in engineering). When positive dividends are introduced, the model in Chen and Liang (SIAM Financ. Math. 12, 941–966, 2021) may not be well-posed. Here, in this paper, a new model is proposed to include the realistic nonzero dividend scenarios. The key feature of the new model is that partial differential equations in Chen and Liang (SIAM Financ. Math. 12, 941–966, 2021) are replaced by variational inequalities, thereby creating a new free boundary, besides the original upgrading and downgrading free boundaries. Well-posedness of the new model, together with a few financially meaningful properties, is established. In particular, it is shown that when time to debt paying deadline is long enough, the underlying dividend paying company is always in high grade rating, that is, only when time to debt paying deadline is within a certain range, there can be seen the phenomenon of credit rating migration.

This study seeks to determine the impact of remittances and nonlabor income on the duration of unemployment, and therefore on the hysteresis phenomenon in Colombia for the period between January 2010 and January 2021. The long-term unemployment rate in Colombia (LAPU) is calculated, and a vector autoregressive (VAR) model is subsequently estimated to evaluate the impact of remittances and nonlabor income on the LAPU. The results suggest that the increase in nonlabor income significantly affected LAPU in Colombia in the period analyzed. The growth of remittances instead turned out to positively and significantly impact LAPU only during the COVID-19 pandemic crisis. This suggests that remittances have become a fundamental income in times of crisis that allow for financing the search for work for a longer period of time, thus increasing the duration of unemployment and generating a hysteresis effect.

Understanding seed moisture desorption and adsorption isotherms is important for seed quality maintenance and better predicting seed storage lifespan. Freshly harvested oilseed rape and barley seeds were dried and then rehydrated twice. Seed equilibrium relative humidity (eRH) and moisture content (MC) were determined at different humidity levels so that two cycles of desorption and adsorption could be constructed. In addition, seeds were dried to 30% RH and then rehydrated to 50% RH for five cycles to determine whether they shift to the adsorption isotherm. Monolayer MC was determined using the Gugenheim-Anderson-de Boer model. Storage experiments were conducted for seeds equilibrated at 30, 40, 50, 60 and 70% RH for two cycles of desorption and adsorption at 45°C. Isotherm curves’ shapes were similar for oilseed rape and barley, although spanning a greater MC range in barley. The hysteresis effect was observed for oilseed rape and barley seeds when dried over silica gel at <10% RH. However, this effect was only observed for barley seeds when dried to 30% RH, but not for oilseed rape seeds. Longevity was greater for adsorbing seeds than desorbing seeds at a given eRH, however, there was no significant difference in σ (the standard deviation of the normal distribution of seed deaths over time)–MC log–log relationship. The relationship shifted for seeds on the second cycle. In conclusion, if seed lots are stored at a specific RH, reaching equilibrium by desorption or adsorption can strongly influence their longevity. Also, when seeds of different species are dried to low RH, they will respond differently to a subsequent increase in RH, which could profoundly affect their longevity.