Negative Deviations Research Articles

Changes in atmospheric circulation and glacier melting since the last deglaciation revealed by a lacustrine δD record at Ngamring Co, the upper-middle Yarlung Tsangpo watershed

Both the Indian Summer Monsoon (ISM) and glacier meltwater are suggested to significantly influence the modern discharge of the Yarlung Tsangpo River, which is the longest river of Tibet and is an important freshwater source for the local population as well as for the large populations in India and Bangladesh in the lower reaches. Understanding past hydroclimatic variations of the region is therefore important for predicting future changes under global warming scenarios. Here we present a continuous compound-specific hydrogen isotope record of sedimentary leaf waxes covering the past 18 ka (ka = 1000 yr) from Ngamring Co, located in the upper-middle Yarlung Tsangpo range, a typical monsoonal region, with the aim of documenting hydroclimatic changes since the last deglaciation. Compared with measurements of continuous scanning XRF and magnetic susceptibility, the δD at Ngamring Co is believed to reflect atmospheric circulation and glacial meltwater input rather than direct local humidity. In detail, the record indicates relatively enriched δD values during the Late Pleistocene, suggesting the predominance of the Westerlies and limited moisture delivery by the ISM, which was associated with cooling at high northern latitudes. The fast δD depletion indicates that ISM penetrated into TP since ~10.5 ka BP (before present, the present is 1950 CE), then the gradually increased δD values suggested the ISM attenuated in phase with summer insolation during early to middle Holocene. The negative deviation of δD (>80‰, abrupt depleted at 3 ka BP) since ~6 ka BP suggested glacier melting in the catchment and ended at ~0.2 ka BP, which emphasizes the glacial contribution to the hydroclimatic change in Yarlung Tsangpo watershed. Such depletion was also observed at Aweng Co in the western TP, which suggests that a glacier meltwater contribution to lakes and rivers may be a large-scale phenomenon on the TP. Comparison of the δD record from Ngamring Co with independent paleotemperature records indicates the control of summer temperature/insolation on glacier melting may not be the most important factor during the late Holocene, and instead we propose that the mean annual air temperature and glacier volume were more crucial to the melting process. If our inference is correct, the disappearance of a glacier from the Ngamring Co basin at ~0.2 ka BP is likely to be indicative of the fate of other glaciers on the TP under ongoing global warming. However, independent reconstructions of temperature and direct glacier dynamics from the same site are needed to validate our hypothesis.

Mass spectrometric study and modeling of the thermodynamic properties in the Gd2 O3 -ZrO2 -HfO2 system at high temperatures.

Materials based on the Gd2 O3 -ZrO2 -HfO2 system are promising for a wide range of high-temperature technological applications, such as for obtaining thermal barrier coatings in the aviation and space industry, as well as advanced materials in nuclear power applications. Experimental studies of the ceramics based on this system by the Knudsen effusion mass spectrometric method provides such valuable information as the vapor composition over the samples and enables derivation of the thermodynamic functions. Samples of ceramics in the Gd2 O3 -ZrO2 -HfO2 system were synthesized and analyzed by X-ray fluorescence and diffraction techniques. The vaporization processes and partial pressures of the vapor species over the samples were obtained by the high-temperature mass spectrometric method using the ion current comparison method. The derived thermodynamic functions were optimized within the Generalized Lattice Theory of Associated Solutions (GLTAS) approach. At the temperature of 2600 K, the GdO, ZrO, ZrO2 , HfO, and O vapor species were found over the samples, but only for the GdO and ZrO species were accurate experimental data on the partial pressures obtained. In all the ceramic samples, the Gd2 O3 activity was determined. On this experimental basis, modeling within the GLTAS approach was performed. It allowed the evaluation of the Gd2 O3 , ZrO2 , and HfO2 activities in the system under study and a rough approximation of the excess Gibbs energy as a function of composition to be obtained. At 2600 K the Gd2 O3 -ZrO2 -HfO2 system is characterized by negative deviations of its thermodynamic properties from the ideal behavior. Consistency of the obtained modeling results indicate reasonable uniformity of the energy parameters of the lattice model derived in calculations of the hafnia-containing oxide systems, which may be used in further modeling of multicomponent systems.

Influence of Ball-End Milling Strategy on the Accuracy and Roughness of Free Form Surfaces

Freeform surfaces are present on an increasing number of engineering products. Three- and multi-axis computer numerical control milling machines are commonly used for improved production. Computer-aided manufacturing (CAM) systems are used almost exclusively for the creation of programs for a variety of machining centers. This study compared the quality of freeform surfaces made by 3- and 5-axis milling using three commonly used strategies (linear, offset, and spiral). The CAM system-predicted surfaces were also compared with the actual surfaces. A test sample with a freeform surface was used for the experiments. Considering the size and distribution, the discrepancy between the predicted surface deviations and the deviations in the produced samples was proven. Maximum negative surface deviations, when 5-axis milling, employed linear and spiral strategy of 29% and 71% less than those produced by the 3-axis milling. On the contrary, positive deviations were 48% smaller. A comparison of the scans showed that the two strategies (linear and spiral) yielded better results for 5-axis milling, and the offset strategy was better for 3-axis milling. Evaluation of the achieved surface roughness showed that the milling method did not significantly affect the surface quality in the linear strategy. However, other two strategies (offset and spiral) achieved better results with 5-axis milling compared to 3-axis milling. The proposed method of evaluating the accuracy of machined free form surfaces can be used in experimental as well as production activities.

Financial Disclosure Practices of Private Commercial Banks in Bangladesh: A Compliance Study

The study is based on analysis of compliance of prevailing accounting standards for the Private Commercial Banks in Bangladesh. This paper empirically analyzed the performance of disclosure in compliance with IFRS 7. 6 listed private banking companies taken as sample. To fulfil its objective, the annual reports and documents of all the sample banks are examined and obtained data from surveys. Since all of them are required to comply with the standard of IFRS 7 to disclose relevant financial information to uphold the stakeholders’ interest, the extent of deviation from the standards in terms of disclosure practice is also examined. The study found that average compliance of the standards is 72.77% by the banks. The highest rate of compliance found from individual compliance status of those companies is 80% with a negative deviation from average. However, the practices of disclosure in reporting are considerably good. Therefore, it is recommended that the regulatory authority and central bank of Bangladesh should mandate the compliance of IFRS 7 for disclosure in financial reporting.

Evaluation of Warm-Season Rainfall Diurnal Variation over the Qilian Mountains in Northwest China in ERA5 Reanalysis

On the basis of hourly rain-gauge data from 735 stations over the Qilian Mountains in Northwest China, the rainfall diurnal variation represented in ERA5 reanalysis data from the European Centre for Medium-Range Weather Forecasts (ECMWF) was evaluated from May to October during 2012–2019. Results show that rainfall with intensities below 4 mm h−1 was mostly overestimated, while intensities above 4 mm h−1 were underestimated in ERA5. The most severe overestimation of weak precipitation occurs in the late afternoon, while heavy precipitation is mostly underestimated at night. Deviation in both heavy and weak precipitation is more evident in mountainous areas. The diurnal peak was reasonably reproduced for the rainfall events with durations shorter than 4 h, while the peak hour of events with longer duration showed evident bias. The positive (negative) deviations of short (long) duration rainfall events mainly appear in the late afternoon (night). Around the Qilian Mountains, where deviation is pronounced, the bias of afternoon short-duration events is influenced by higher-frequency precipitation, while the bias of long-duration events is related to the lower frequency of precipitation at night. In terms of the spatial distribution of precipitation with varied elevation, ERA5 fails to represent variation in weak and heavy precipitation with increasing elevation, which may be related to the deviation of surface-specific humidity in reanalysis. The results of this study imply the uncertainty of rainfall products by ERA5 over regions with complex topographic effects and provide metrics to evaluate rainfall products or forecasts over complex terrain area.

ИЗМЕНЧИВОСТЬ УРОЖАЙНОСТИ ЗЕРНОВЫХ И ЗЕРНОБОБОВЫХ КУЛЬТУР В КИРОВСКОЙ ОБЛАСТИ

The purpose of the research is to identify the trends and factors of variability in the yield of the main agricultural crops in Kirov region. The study was conducted on the basis of data from the territorial body of Federal State Statistics Service for Kirov region for 2001-2020. An analysis of the regression equations showed that the yield dynamics for the analyzed period is most accurately described by a 2nd degree polynomial. The yield of grain and leguminous crops over a twenty-year period varied from 12.6 to 21.7 q/ha. The average yield for five years varied from 14.2 q/ha in 2001-2005 up to 19.6 c/ha in 2015-2020 The yield variation coefficient for five years varied from 8.6 to 15.5%, and the yield stability coefficient - from 91.4 to 84.5%, respectively. The highest yield was achieved in the last five years, due to the use of intensive production technologies. In addition to agricultural technology, productivity is also affected by factors of agrometeorological origin. According to the results of calculations, about 10% of the yield depends on the influence of weather and climatic conditions, respectively, 90% of the yield variation is due to the culture of agriculture. According to the results of calculations of positive and negative deviations of the actual yield from the dynamic average, it was revealed that the increase in yield in favorable years in terms of weather and climatic conditions can be 4.1 centners per hectare, and the shortfall in yield in unfavorable years will be 3.7 centners per hectare. Calculation of the climatic component according to the method of Pasov V.M. showed that the Kirov region belongs to the zone of moderately stable crops

Ultra-high resolution δ18O of land snail shell: A potential tool to reconstruct frequency and intensity of paleoprecipitation events

Extreme rainfall events cause tremendous threats to people’s lives and economic well-being. Given the short time span of instrumental records, reconstructing the full range of past rainfall variability using available proxies is impossible when trying to unravel the history and underlying mechanisms of extreme precipitation events. However, this work is usually limited by the temporal resolution of current paleoclimate records. Here we demonstrate that the ultra-high resolution measurements of δ18O of terrestrial snail shells of Cathaica fasciola (Draparnaud, 1801) can be used to reconstruct the rainfall variability on weather time scales. Broadly, the modern daily time resolution snail shell’s δ18O profile shows a negative trend from late March to September in 2020, which resembles the variations of monitored δ18O and amount of precipitation. Meanwhile, six abrupt negative deviations were observed in the δ18O profiles and these deviations matched well with the instrumental precipitation events for the same period. The high correlation of shell’s δ18O with rainfall amount during the six precipitation events indicates that the ultra-high resolution δ18O records of gastropod shells have the potential to qualitatively record local synoptic rainfall events. Our study highlights that the terrestrial gastropod shell could provide daily to weekly geochemical proxies and has the potential to be used as an ultra-high resolution archive for characterizing terrestrial paleoweather, such as extreme precipitation events.

Liquefying Flavonoids with Terpenoids through Deep Eutectic Solvent Formation.

The formation of deep eutectic solvents (DES) is tied to negative deviations to ideality caused by the establishment of stronger interactions in the mixture than in the pure DES precursors. This work tested thymol and menthol as hydrogen bond donors when combined with different flavonoids. Negative deviations from ideality were observed upon mixing thymol with either flavone or flavanone, two parent flavonoids that only have hydrogen bond acceptor (HBA) groups, thus forming non-ionic DES (Type V). On the other hand, the menthol systems with the same compounds generally showed positive deviations from ideality. That was also the case with the mixtures containing the more complex hydroxylated flavonoid, hesperetin, which resulted in positive deviations when mixed with either thymol or menthol. COSMO-RS successfully predicted the behavior of the solid-liquid phase diagram of the studied systems, allowing for evaluation of the impact of the different contributions to the intermolecular interactions, and proving to be a good tool for the design of DES.

Importance of triple soluting-out effect in the formation of aqueous three-phase systems: Thermodynamics and applications in extraction of biomolecules

A comprehensive experimental study was conducted on aqueous triphasic systems (A3PSs) to increase molecular understanding of the soluting effect phenomenon occurring in these systems. The influence of several ionic liquids, polymers and salts was studied, demonstrating that a triple soluting-out effect is a required phenomenon to formation of an A3PS. For aqueous quaternary systems 1-butyl-3-methylimidazolium bromide ([Bmim][Br]) + trisodium citrate (Na3Cit) + polypropylene glycol 400 (PPG400) and [Bmim][Br] + disodium sulfate (Na2SO4) + PPG400 which were able to form A3PS, the respective phase diagrams were determined at 318.15 K. For aqueous [Bmim][Br] + Na2SO4 + PPG400 system, the equilibrium compositions of three coexisting phases (tie-surfaces) were determined. The results showed that, there are an aqueous polymer-rich phase with the least amount of water (top phase), an aqueous salt-rich phase with the greatest amount of water (bottom phase), and an aqueous IL/polymer-rich phase with large amount of water (middle phase). In order to study the soluting effects occurring in these systems, deviations from the semi-ideal behavior were addressed using the isopiestic measurements. The obtained evidence showed that the triple soluting-out effect is resulted from the unfavorable IL-salt, IL-polymer, and polymer-salt, interactions and it leads to preferential hydration of solutes and thereby creation of three aqueous polymer-rich, salt-rich, and IL/polymer-rich phases in solution for entropy reason. From isopiestic data, for quaternary solutions the constant water activity lines in mono- and biphasic regions show large negative deviations from the semi-ideal hydration model and magnitude of these deviations in monophasic region are larger than those in biphasic region. In three-phasic solutions, the values of deviations became positive. The distribution behavior of three amino acids including L-proline (Pro), L-phenylalanine (Phe), and L-leucine (Leu) in aqueous [Bmim][Br] + Na2SO4 + PPG400 three-phase system was investigated. The results showed that, because of hydrophilic property of the studied amino acids and some favorable amino acid-IL interactions, these analytes are more enriched in the salt-rich or IL/polymer-rich phases than in the polymeric phase.

Limits of the simple pendulum formula for classroom use

We discuss the limits of the equation of the period of a simple pendulum, , frequently used in high-school and university classrooms to measure the acceleration of gravity. We evaluate the relative error in determining the acceleration of gravity with this simple equation instead of a more realistic one, taking into account the string’s mass, the bob’s radius, and finite angular displacements. We show that the bob radius and finite angular displacements increase the period of oscillation of the pendulum and, hence, contribute to a positive deviation in the value of g calculated with the simple pendulum formula. On the other hand, the string’s mass decreases the pendulum’s period and induces a negative deviation in the value of g. As a result, it is possible to adapt the pendulum’s characteristics to use the simple pendulum formula and calculate g with accuracy.

Glass Transition Temperatures of Copolymers: Molecular Origins of Deviation from the Linear Relation

The glass transition temperature (Tg) is an important material parameter in determining polymer properties. The main molecular structure factors affecting Tg are chain stiffness and cohesive energy, causing polymers to exhibit the complex micro-structure dependence of Tg. The composition dependence of the Tgs of binary random copolymers mainly shows as three cases: the linear relation, the negative deviation (or concave curve), or the positive deviation (convex curve). The study of the Tg’s composition dependence can guide the design of copolymer materials with desirable properties. On the other hand, it can provide insights into understanding the precise nature of the glass transition. In this study, the root cause of the Tg deviation from the linear relation in random copolymers was revealed, and new molecular origins were proposed. First, the theoretical basis of why there exists a linear Tg relation for copolymers was clarified, and the influence of the specific polar interactions between components was discussed briefly. More importantly, it has been identified that the negative Tg deviation is related to copolymers composed of the mono-substituted (M-type) monomer and asymmetrical di-substituted (AD-type) monomer, and the positive Tg deviation is related to copolymers composed of the M-type monomer and symmetrical di-substituted (SD-type) monomer. The molecular origin of the Tg deviations from the linear relation is the destruction of the special conformational structures (e.g., the locally rigid conformational structure in the AD-type homopolymer or the dynamic flexible structure in the SD-type homopolymer) caused by copolymerization. The behaviors for more complex binary copolymers (AD–AD, SD–SD, and AD–SD types) were also discussed. Finally, the variation in Tg of a statistical copolymer as a function of composition was summarized.

Vaporization and thermodynamic properties of the SrO-Al2 O3 system studied by Knudsen effusion mass spectrometry.

Strontium aluminates can be used as refractory construction materials at temperatures up to 2000°С or as the materials for immobilization of long-lived radioactive waste. The SrО-Al2 O3 system is one of the more complicated oxide systems used for the creation of new radio-transparent materials. The exploitation of such materials at high temperatures demands the knowledge of the thermal stability of the compounds and solid solutions formed in the SrО-Al2 O3 system. The synthesis of the samples in the SrO-Al2 O3 system was carried out by a ceramic method at 1250°C. The characterization of the samples was accomplished with the use of X-ray diffraction (XRD). The vaporization of the samples under study was performed from a twin tungsten effusion cell using the Knudsen effusion mass spectrometry method. The temperature dependences of partial pressures of vapor species over 4SrO·Al2 O3 , 3SrO·Al2 O3 , SrO·Al2 O3 , SrO·2Al2 O3 and SrO·6Al2 O3 in a wide range of temperatures were determined. The component activities, the Gibbs energies of mixing and the standard enthalpies of individual strontium aluminates were obtained. The thermodynamic properties of the SrO-Al2 O3 system at high temperatures are characterized by negative deviation from ideality. The vaporization processes and thermodynamic properties of the SrO-Al2 O3 system were obtained for the first time.

Effects of the hemolytic index on the test results of a dry chemistry analyzer and a verification of the hemolytic interference threshold.

This study verified and assessed 26 biochemical indicators tested by a dry chemistry analyzer using the hemolytic index test function to determine the degree of interference and the trends among the hemolysis samples on the test results. This study also sought to ensure that reasonable test reports could be issued taking into account practical clinical needs. The samples were manually divided into the control group and the test group. The hemolytic index and biochemical indicators of the samples were tested using the Ortho Vitros 5600 to compare the deviation of the test results between the 2 groups. The judgment standard was set as 1/3 of the total error allowable as required by the quality assessment criterion of the National Center for Clinical Laboratories. The interference degree of hemolysis on the dry chemistry-based biochemical indicators was assessed, and the hemolytic thresholds of 26 biochemical indicators provided by the manufacturer were verified in terms of their validity and rationality. The hemolytic thresholds of 26 dry chemistry-based biochemical indicators were verified to analyze the degree of interference. The results revealed that hemolysis interfered with 17 indicators. Hemolysis positively interfered with the test results of phosphorus, creatine kinase, gamma glutamyl transpeptidase (γ-GGT), magnesium, iron, total protein, potassium, total bilirubin, lactate dehydrogenase, albumin, and aspartate aminotransferase, but negatively interfered with cholinesterase, direct high-density lipoprotein cholesterol, glucose, elevated carbon dioxide alkaline phosphatase, and alanine aminotransferase. A negative deviation of γ-GGT by hemoglobin was described in the manufacturer's statement, but our test data showed a positive deviation by hemolysis. The hemolytic threshold verification results of the other biochemical indicators were consistent with the manufacturer's statement. The hemolytic index test function was used to determine which samples were interfered with by hemolysis to make an analytical judgment according to the hemolytic interference thresholds of the different test items, verify the validity of the hemolytic thresholds of the test items, perform reasonable tests on the hemolytic samples, and issue valid reports to reduce the rejection rate of the hemolytic samples, shorten the turnaround time (TAT) of laboratories.

Influence of roller mounting angle on the spinnability of conical spun parts with thin wall

Abstract Using self-developed automatic control spinning equipment, the shear spinning process under 20°, 30° and 40°of roller mounting angle was carried out on the thickness of 0.5 mm for 1060 aluminum alloy to study the characteristics of microstructure, wall thickness reduction, wall surface quality defects. The results show that the roller mounting angle obviously affects on the spinnability of conical spun parts with thin wall, however, it hardly affects their microstructure evolution. When the roller mounting angle is 30°, i.e. in other words the optimal mounting angle is equal to the half cone angle of the core mold. And the conical wall height of the conical spun part is the highest, and the thickness of the conical wall is uniform, the surface is smooth, and there is no obvious appearance defect. It is found that whether the roller mounting angle is larger or smaller than the half cone angle of the core mold, it will lead to negative deviation from the spinning, even if it does not reach an increase of 90°, only an increase or decrease of 10°, the conical spinning part soon appears circumferential cracking of the sidewall, and the phenomenon of material accumulation in front of the cracking all appears.

Imbalanced segregation of recombinant haplotypes in hybrid populations reveals inter- and intrachromosomal Dobzhansky-Muller incompatibilities.

Dobzhansky-Muller incompatibilities (DMIs) are a major component of reproductive isolation between species. DMIs imply negative epistasis and are exposed when two diverged populations hybridize. Mapping the locations of DMIs has largely relied on classical genetic mapping. Approaches to date are hampered by low power and the challenge of identifying DMI loci on the same chromosome, because strong initial linkage of parental haplotypes weakens statistical tests. Here, we propose new statistics to infer negative epistasis from haplotype frequencies in hybrid populations. When two divergent populations hybridize, the variance in heterozygosity at two loci decreases faster with time at DMI loci than at random pairs of loci. When two populations hybridize at near-even admixture proportions, the deviation of the observed variance from its expectation becomes negative for the DMI pair. This negative deviation enables us to detect intermediate to strong negative epistasis both within and between chromosomes. In practice, the detection window in hybrid populations depends on the demographic scenario, the recombination rate, and the strength of epistasis. When the initial proportion of the two parental populations is uneven, only strong DMIs can be detected with our method unless migration prevents parental haplotypes from being lost. We use the new statistics to infer candidate DMIs from three hybrid populations of swordtail fish. We identify numerous new DMI candidates, some of which are inferred to interact with several loci within and between chromosomes. Moreover, we discuss our results in the context of an expected enrichment in intrachromosomal over interchromosomal DMIs.

Thermodynamics of mixtures containing amines. XVII. [formula omitted] and [formula omitted] measurements for benzylamine + heptane or + 1-alkanol mixtures at 298.15 K. Application of the DISQUAC and ERAS models

Excess molar enthalpies, HmE, at 298.15 K and 0.1 MPa have been measured by means of a Tian-Calvet microcalorimeter for the systems benzylamine (phenylmethanamine) + heptane, or + methanol, or + 1-propanol, or + 1-pentanol, or + 1-heptanol, or + 1-decanol. In addition, excess molar volumes, VmE, at the same conditions have been also determined using a densimeter Anton Paar model DSA 5000 for the benzylamine + heptane mixture. The HmE of this solution is large and positive since at 298.15 K the system temperature is close to its upper critical solution temperature. Thus, systems with n-alkanes show positive deviations from the Raoult's law. The measured |VmE| values are low, indicating the existence of large structural effects. HmE values of mixtures involving 1-alkanols are large and negative. That is, interactions between unlike molecules are dominant and the systems are characterized by negative deviations from Raoult's law. It is shown that the enthalpy of the hydrogen bonding between molecules of 1-alkanol and benzyalmine are more negative than those between 1-alkanol molecules. The VmE values of the systems with 1-alkanols are also large and negative, and are determined mainly by interactional effects since they increase in line with HmE and with the alcohol size. The different contributions to HmE have been evaluated. The systems have been studied using the DISQUAC and ERAS models. ERAS describes correctly the VmE function. DISQUAC largely improves ERAS results on HmE or on excess molar heat capacities at constant pressure for the mixtures with 1-alkanols, which underlines that physical interactions are very relevant in such solutions.

Surface tension measurements and modelling of n-Hexadecane + n-Dodecane, n-Hexadecane + 2,2,4,4,6,8,8-Heptamethylnonane, n-Hexadecane + n-Octacosane and n-Hexadecane + Squalane binary mixtures between (303 and 573) K by pendant drop method

This work contributes to the experimental measurements and modelling of the surface tension for the medium- to long-chained hydrocarbon mixtures involved in the Fischer-Tropsch process under the high-temperature conditions. For this purpose, the experimental surface tension measurements for the four investigated binary mixtures of n-Hexadecane with n-Dodecane, 2,2,4,4,6,8,8-Heptamethylnonane, n-Octacosane and Squalane were performed by pendant drop method at temperatures up to 573.15 K covering the mass fractions of wn-Hexadecane = (0.25, 0.50 and 0.75). The combined expanded uncertainties of temperature, mole fraction and surface tension with a level of confidence of 0.95 (k = 2) are estimated to be 20 mK, within 0.6% and less than 2.2% over the entire temperature, respectively. On the basis of the surface tension correlations of pure substances in our previous study, the experimental surface tension data of the four investigated binary mixtures were correlated with the three-parameter Jouyban − Acree model and two-parameter Fu-Li-Wang (FLW) model. However, the experimental results show increasing negative deviations from Jouyban − Acree model with maximum values up to −2.66% and increasing positive deviations from FLW model with maximum values up to 9.93% in the high temperature zone. Therefore, we proposed a new model for correlating the surface tension of multicomponent mixtures with excellent reproducibility. The relative deviations of the experimental data from the present model are distributed evenly on both sides of the zero line and the relative absolute deviations are within 0.6%.

Neurodevelopmental Trajectories in Children With Internalizing, Externalizing and Emotion Dysregulation Symptoms.

IntroductionChildhood and adolescence are crucial periods for brain and behavioral development. However, it is not yet clear how and when deviations from typical brain development are related to broad domains of psychopathology.MethodsUsing three waves of neuroimaging data within the population-based Generation R Study sample, spanning a total age range of 6–16 years, we applied normative modeling to establish typical development curves for (sub-)cortical volume in 37 brain regions, and cortical thickness in 32 brain regions. Z-scores representing deviations from typical development were extracted and related to internalizing, externalizing and dysregulation profile (DP) symptoms.ResultsNormative modeling showed regional differences in developmental trajectories. Psychopathology symptoms were related to negative deviations from typical development for cortical volume in widespread regions of the cortex and subcortex, and to positive deviations from typical development for cortical thickness in the orbitofrontal, frontal pole, pericalcarine and posterior cingulate regions of the cortex.DiscussionTaken together, this study charts developmental curves across the cerebrum for (sub-)cortical volume and cortical thickness. Our findings show that psychopathology symptoms, are associated with widespread differences in brain development, in which those with DP symptoms are most heavily affected.

A mechanism for the skew of ensemble forecasts

AbstractIt is often not appreciated that forecast ensembles are generally skewed. The skew can arise from the state dependence of the chaotic system dynamics responsible for the ensemble spread. Generation of skew by this mechanism can be demonstrated in even the simplest dynamical system with state‐dependent noise, and even when the initial and the asymptotic (i.e., the “climatological”) forecast distributions are both symmetric. Indeed, forecast distributions of systems with state‐dependent noise in the dynamical tendencies must in general be both skewed and heavy tailed, with implications for forecasting extreme anomaly risks. Ensemble forecast systems that misrepresent such state‐dependent noise have state‐dependent errors in their forecast probability distributions. Because such errors depend on both the initial condition and forecast lead time, they cannot be removed by simple a posteriori bias corrections of the forecast distributions. The ensemble standard deviation is often used as a simple metric of ensemble spread even when the forecast distribution is not Gaussian. In a similar spirit, the ensemble skew S may be used as a simple metric of the difference D between the ensemble‐mean and most likely forecast, as well as the risk ratio R of extreme positive and negative deviations from the ensemble‐mean forecast. This is motivated by the facts that (1) the probability distributions of many geophysical quantities are approximately stochastically generated skewed (SGS) distributions, for which simple analytical relationships exist between these quantities, and (2) Gaussian distributions are a sub‐class of SGS distributions. However, S may serve as a useful metric of R and D even when the distributions are not strictly SGS distributions.

Beware of Pitfalls in the European Central Bank’s Review of Monetary Policy Strategy

Abstract The long-awaited Review of Monetary Policy Strategy of the European Central Bank has been released. According to the Governing Council, “price stability is best maintained by aiming for 2% inflation over the medium term”, with “symmetric commitment” to this target. “Symmetry means that the Governing Council considers negative and positive deviations from this target as equally undesirable”. This orientation seems contrarian to the view, expressed by some dissenting scholars, that 2% should be set as a ceiling, and that persistent inflation below 2% observed over the last decade was to be adopted as the “new normal”. The aim of this paper is not to examine and assess the new policy strategy of the ECB per se, but to warn about pitfalls in detecting undesirable (expectation-driven) deviations of inflation from target versus permanent changes in the ouput-inflation relationship.