Inverted U-shaped Pattern Research Articles

Wagner’s law versus displacement effect

ABSTRACTThe public sector has grown dramatically over the past few centuries in many developed countries. In this article, we use wavelet methods to distinguish between two leading explanations for this growth – Wagner’s law and the displacement effect. In doing so, we use the long-term data of 10 OECD countries for a maximum time span of 1800–2009. We find that the validity of Wagner’s law is likely to vary strongly over time for each country. A roughly similar feature in most of the countries is that the law is less valid in the earliest stage of economic development as well as in the advanced stages, with the validity tending to follow an inverted U-shaped pattern with economic development. Further, our results indicate that the long-run growth of government size cannot be adequately explained by Wagner’s law. On the other hand, the displacement effect appears to account for the bulk of the growth in most of the countries.

Intraocular pressure elevation after intravitreal triamcinolone acetonide injection: a Meta-analysis.

To report on intraocular pressure (IOP) after intravitreal injections of triamcinolone acetonide. Systematic literature review of studies that investigated the effects of an injection of triamcinolone intravitreal triamcinolone acetonide on IOP was conducted according to the Cochrane Collaboration methodology and the reported effects have been analyzed with Meta-analysis. We found that the IOP follows an inverted-U shape pattern over time starting with an average value of 14.81±1.22 mm Hg before the injection, rising to a maximum of 19.48±2.15 mm Hg after one month of injection and falling down to 16.16±1.92 mm Hg after 6mo. Moreover, country of study, age, previous history of glaucoma and gender compositions matter for cross-study were different in reported IOP changes. Our findings may be helpful in determining pressure elevation risk of intravitreal triamcinolone acetonide therapy as well as comparing it with those of more recent therapies such as the anti-vascular endothelial growth factor agents.

Integração fracionária nos ciclos econômicos de longo prazo no Brasil: evidências iniciais de criticalidade auto-organizada

O presente artigo estuda os ciclos economicos no Brasil sob a otima da teoria da criticalidade auto-organizada (SOC), em que as flutuacoes ocorrem como avalanches que se constroem lentamente no tempo, em um sistema dinâmico conduzido endogenamente para o ponto critico. Para tanto, obteve-se uma serie de ciclos de longo prazo com a tecnica de Analise do Espectro Singular, a qual foi, entao, utilizada em modelos ARFIMA (p,d,q). A serie considerada foi o produto interno bruto (PIB) trimestral, disponivel entre 1947 e 2012. Os resultados mostram que os ciclos de longo prazo podem durar de tres a pouco mais de 12 anos, com media de nove anos. Os periodos de arrefecimento da atividade tem duracao aproximada de cinco anos e taxa de crescimento relativamente baixa, de 2,9% a.a. Nos periodos expansivos a duracao e ligeiramente menor, 3,75 anos, e a taxa de crescimento e elevada, de 6,9% a.a. Em adicao, a volatilidade da producao apresenta um padrao em U invertido, atingindo um pico na metade da decada de 1980. As estimacoes ARFIMA indicam fortemente que d ≈ 0,5, exatamente o valor previsto pelo modelo seminal SOC. Assim, nao e possivel rejeitar a viabilidade desta teoria para o caso brasileiro, a qual diz, como corolario, que as flutuacoes ciclicas da producao sao em grande parte inevitaveis.

Early communication deficits in the Shank1 knockout mouse model for autism spectrum disorder: Developmental aspects and effects of social context.

Alterations in SHANK genes were repeatedly reported in autism spectrum disorder (ASD). ASD is a group of neurodevelopmental disorders diagnosed by persistent deficits in social communication/interaction across multiple contexts, with restricted/repetitive patterns of behavior. To date, diagnostic criteria for ASD are purely behaviorally defined and reliable biomarkers have still not been identified. The validity of mouse models for ASD therefore strongly relies on their behavioral phenotype. Here, we studied communication by means of isolation-induced pup ultrasonic vocalizations (USV) in the Shank1 mouse model for ASD by comparing Shank1(-/-) null mutant, Shank1(+/-) heterozygous, and Shank1(+/+) wildtype littermate controls. The first aim of the present study was to evaluate the effects of Shank1 deletions on developmental aspects of communication in order to see whether ASD-related communication deficits are due to general impairment or delay in development. Second, we focused on social context effects on USV production. We show that Shank1(-/-) pups vocalized less and displayed a delay in the typical inverted U-shaped developmental USV emission pattern with USV rates peaking on postnatal day (PND) 9, resulting in a prominent genotype difference on PND6. Moreover, testing under social conditions revealed even more prominently genotype-dependent deficits regardless of the familiarity of the social context. As communication by definition serves a social function, introducing a social component to the typically nonsocial test environment could therefore help to reveal communication deficits in mouse models for ASD. Together, these results indicate that SHANK1 is involved in acoustic communication across species, with genetic alterations in SHANK1 resulting in social communication/interaction deficits. Autism Res 2016, 9: 696-709. © 2015 International Society for Autism Research, Wiley Periodicals, Inc.

Effort provision in entrepreneurial teams: effects of team size, free-riding and peer pressure

This paper analyzes whether effort provision in entrepreneurial teams depends on the size of the team, assuming that size determines the strength of free-riding and peer pressure effects in entrepreneurial teams. We provide a theoretical model and empirical analyses to explain the joint effect of free-riding and peer pressure on effort in start-up teams. We begin with an economic model by Kandel and Lazear in J Polit Econ 100(4):801–817, (1992) and enrich it using insights from entrepreneurship research. Based on our model, we first hypothesize that with increasing team size in entrepreneurial teams, the efforts of the individual team founders should follow an inverted U-shaped pattern. Second, we argue that the peer pressure effect is stronger if team members have stronger social ties, and thus we expect the effort-maximizing team size to be larger in teams with stronger social ties. Using a data set from 214 German start-up teams, we find that our hypotheses are supported by the data.

Detecting the Impacts of Socioeconomic Factors on Regional Severity of Work-Related Casualties in China

ABSTRACTWork-related casualties always cause serious damages to regional social and economic development. China's rapid development is raising a series of concerns about work-related casualties. The self-organizing maps (SOM) approach is applied in this study to detect the impacts of socioeconomic factors on the severity of work-related casualties in 31 regions of mainland China. The results show that: (1) the regional severity of work-related casualties and socioeconomic development seem to follow an inverted U-shaped pattern (i.e., the number of work-related fatalities increases to a peak at a certain stage and then decline along with socioeconomic development); (2) the industrial and employment structure have negative correlation with the regional severity of work-related casualties, specifically, the higher percentage of tertiary industry in gross regional product (GRP) and percentage of employed persons in tertiary industry may lead to fewer numbers of work-related fatalities in one region; (3) some socioeconomic factors like education level, medical condition, and insurance coverage have negative impacts on the regional severity of work-related casualties. Furthermore, the study also shows that the SOM approach is capable of improving clustering quality and visualization effects when facing multidimensional datasets compared with traditional cluster approaches such as K-Means and hierarchical-based clustering methods.

The Ontogeny of the Human Connectome

The human brain comprises distributed cortical regions that are structurally and functionally connected into a network that is known as the human connectome. Elaborate developmental processes starting in utero herald connectome genesis, with dynamic changes in its architecture continuing throughout life. Connectome changes during development, maturation, and aging may be governed by a set of biological rules or algorithms, forming and shaping the macroscopic architecture of the brain’s wiring network. To explore the presence of developmental patterns indicative of such rules, this review considers insights from studies on the cellular and the systems level into macroscopic connectome genesis and dynamics across the life span. We observe that in parallel with synaptogenesis, macroscopic connectome formation and transformation is characterized by an initial overgrowth and subsequent elimination of cortico-cortical axonal projections. Furthermore, dynamic changes in connectome organization throughout the life span are suggested to follow an inverted U-shaped pattern, with an increasingly integrated topology during development, a plateau lasting for the majority of adulthood and an increasingly localized topology in late life. Elucidating developmental patterns in brain connectivity is crucial for our understanding of the human connectome and how it may give rise to brain function, including the occurrence of brain network disorders across the life span.

The environmental kuznets curve in Asia: The case of sulphur and carbon emissions

The present study examines whether the Race to the Bottom and Revised EKC scenarios presented by Dasgupta and others (2002) are, with regard to the analytical framework of the Environmental Kuznets Curve (EKC), applicable in Asia to representative environmental indices, such as sulphur emissions and carbon emissions. To carry out this study, a generalized method of moments (GMM) estimation was made, using panel data of 19 economies for the period 1950-2009. The main findings of the analysis on the validity of EKC indicate that sulphur emissions follow the expected inverted U-shape pattern, while carbon emissions tend to increase in line with per capita income in the observed range. As for the Race to the Bottom and Revised EKC scenarios, the latter was verified in sulphur emissions, as their EKC trajectories represent a linkage of the later development of the economy with the lower level of emissions while the former one was not present in neither sulphur nor carbon emissions.

Maternal separation induces alterations of serotonergic system in different aged rats

Maternal separation (MS) induces profound behavioral and neurochemical dysregulations in adult rodents. In the present longitudinal study, we investigated the effects of repeated (4h/day) maternal separation during postnatal days 1-21 on serotonergic synthesis and activity in the prefrontal cortex (PFC), nucleus accumbens (NAc) and hippocampus of juvenile (post-natal day 21, PND 21), adolescent (PND 35) and early adult (PND 56) male Wistar rats. We found that MS increased 5-HT levels in the PFC of juvenile rats, and although MS increased 5-HT and 5-HIAA levels in the NAc of adolescent rats, the ratio between 5-HIAA and 5-HT decreased in the PFC. In addition, MS-treated adult rats showed increased levels of 5-HT in the PFC as well as 5-HT and 5-HIAA in the NAc. These data provided evidence that MS leads to profound and age-specific changes in serotonergic synthesis and activity in rodents. Our study also found that there are U-shaped and inverted U-shaped patterns for serotonergic synthesis and serotonergic activity from younger rats to adults, respectively. Together, our findings support the use of maternal separation as an animal model for studying the neurobiological pathogenesis of neurodevelopmental diseases.

Prespeech Vocalizations and the Emergence of Speech: A Study of 1005 Spanish Children

This study investigates 12 prespeech vocal behaviors which are taken to reflect children's phonological, communicative and early symbolic development. It explores their development (onset, duration and extinction) and their relation to early lexical development. A structured parental questionnaire on prespeech vocalizations was developed, validated and used for the evaluation of 1005 Spanish children's early vocal development (8-30 months). In parallel, the same children's productive vocabulary was assessed using the vocabulary section of the European-Spanish MacArthur-Bates Communicative Development Inventories. Results highlight a global inverted U-shaped developmental pattern which emerges from the asynchronous development of the vocal behaviors examined, relating both their emergence and extinction to advances in linguistic development. Moreover, the protracted coexistence of prespeech vocalizations with early speech and their significant correlations with vocabulary size reveal a gradual transition into language. Overall results reinforce and extend previous findings on the development of prespeech vocalizations and establish their relevance as early indexes of linguistic development. Finally, positive evidence on the use of an assisted parental report method for reliably evaluating these developments is provided. Results are discussed within theoretical frameworks that conceive language as the emergent product of complex developmental processes.

Population, affluence, and environmental impact across development: Evidence from panel cointegration modeling

This paper analyzes urban population's and affluence's (GDP per capita's) influence on environmental impact in developed and developing countries by taking as its starting point the STIRPAT framework. In addition to considering environmental impacts particularly influenced by population and affluence (carbon emissions from transport and residential electricity consumption), the paper determines whether and, if so, how those environmental impact relationships vary across development levels by analyzing panels consisting of poor, middle, and rich countries. The development-based panels approach is an improvement on the GDP per capita polynomial model used in the Environmental Kuznets curve and other literature for several reasons: (i) it allows one to determine whether the elasticity of all variables considered varies according to development; (ii) it is arguably a more accurate description of the development process; (iii) it avoids potentially spurious regressions involving nonlinear transformations of nonstationary variables (GDP per capita squared); and (iv) unlike the polynomial model, it allows for the possibility that elasticities are significantly different across development levels but still positive—precisely the relationship expected for the environmental impacts considered here. Whether or not the elasticity for affluence was greater than that for population was a function of both the choice of dependent variable and the makeup of the panel (all countries, poor, middle, or rich). Furthermore, the estimated elasticities varied, in a nonlinear fashion, according to the development process: U-shaped, inverted U-shaped, and monotonic patterns were revealed, again, depending on the dependent variable.

BMI Trajectories Among the Severely Obese: Results From an Electronic Medical Record Population

Epidemiological studies have documented the growing prevalence of severe obesity during the past three decades. The primary goal of this study was to estimate the trajectory of BMI change over 5+ years in a cohort of subjects identified as severely obese (BMI ≥35). We conducted a retrospective cohort study among adults enrolled in Group Health (GH) in Washington State. We tracked 11,735 subjects with at least one BMI measure of 35 or greater in the calendar year 2005 through April 2010. Population averaged BMI trajectories were estimated as a quadratic function of time using a marginal regression model, adjusting for gender and baseline BMI and age. For the average male in GH, the estimated BMI trajectory exhibited a slightly inverted U-shaped pattern and a 0.17 increase in BMI over the sample period. For the average female, the BMI trajectory was slightly U-shaped with BMI decreasing 0.03 units over the sample period. We found a high degree of heterogeneity in the shape of estimated trajectories across baseline characteristics with larger 5-year BMI increases among younger subjects with a lower initial BMI. We conclude that BMI changes over 5 years among individuals classified as severely obese are generally small and consistent with studies documenting BMI changes for individuals in other lower BMI categories. Our results also suggest that once the 35 BMI threshold is reached, individuals will continue to remain severely obese, especially at younger ages.

Systematic review of a new orb-weaving spider genus (Araneae: Araneidae), with special reference to the Australasian-Pacific and South-East Asian fauna

The Australasian-Pacific and South-East Asian species of the new orb-weaving spider genus Plebs with Plebs eburnus (Keyserling, 1886) as type species are revised. Following this study, Plebs includes a total of 22 species of which seven are here described new. Seven species are found in Australia, two in the Pacific region (New Caledonia, Vanuatu), and two in South-East Asia (Papua New Guinea, The Philippines). Eleven Asian species are transferred to the new genus. Plebs represent comparatively small orb-weaving spiders of c. 1.2–15.0 mm body length with a slightly elongated abdomen and humeral (shoulder) humps. Males of most species have two to three stout setae on the ventral side of their fourth coxae. Male pedipalps are characterized by the presence of a single macroseta on the patella, the presence of a paramedian apophysis as basal extension of the conductor, and an apical tegular protrusion. The female epigyne has a scape that is generally much longer than wide. It does not have a terminal pocket and is frequently broken off in a number of species. A phylogenetic analysis of 15 species of Plebs (those for which both sexes are known), 13 Australian/Pacific orb-weaving spider species representing the most commonly collected clades with paramedian apophysis, three species of Nearctic Eriophora Simon, 1864, and Araneus diadematus Clerck, 1758, as outgroup, identified a single synapomorphy of Plebs based on 35 morphological and three behavioural characters: a distinct, inverted U-shaped light pattern on the ventral side of the abdomen with two additional white spots anterolateral to the spinnerets. This analysis recovered a monophyletic clade of all Asian Plebs, suggesting a single colonization event of the genus that putatively originated in Australia. Most Plebs species appear to be active during the day. They build a regular orb-web with vertical stabilimentum in grass and low shrubs. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 166, 279–341.

Inverted U-shaped conformism: An economic model of endogenous responses to the Joneses

Based on sociologists’ findings, it is more likely that middle-status people are “keeping up with the Joneses” while both the highest-status and lowest-status people are “running away from the Joneses”. Existing economic models fail to reproduce this inverted-U shaped (IUS) curve. In my model, response to the Joneses is endogenized and is related to one's status position. Under some reasonable assumptions, an IUS pattern will appear. A comparison with a sociological explanation of the same phenomenon and further implications will also be discussed.

Modulation of Inhibition of Return by the Dopamine D2 Receptor Agonist Bromocriptine Depends on Individual DAT1 Genotype

Involuntary visual spatial attention is captured when a salient cue appears in the visual field. If a target appears soon after the cue, response times to targets at the cue location are faster relative to other locations. However, after longer cue-target intervals, responses to targets at the cue location are slower, due to inhibition of return (IOR). IOR depends on striatal dopamine (DA) levels: It varies with different alleles of the DA transporter gene DAT1 and is reduced in patients with Parkinson's disease, a disease characterized by reduced striatal dopaminergic transmission. We examined the role of DA in involuntary attention and IOR by administering the DA D2 receptor-specific agonist bromocriptine to healthy human subjects. There was no effect of either DAT1 genotype or bromocriptine on involuntary attention, but participants with DAT1 alleles predicting higher striatal DA had a larger IOR. Furthermore, bromocriptine increased the magnitude of IOR in participants with low striatal DA but abolished the IOR in subjects with high striatal DA. This inverted U-shaped pattern resembles previously described relationships between DA levels and performance on cognitive tasks and suggests an involvement of striatal DA in IOR that does not include a role in involuntary attention.

The intraday bid–ask spread behaviour of the JPY/USD exchange rate in the EBS electronic brokerage system

Using a sophisticated tool of the Periodic-Generalized Autoregressive Conditional Heteroscedastic (P-GARCH) model, this article investigates the market institutional effects of the determining role of trading activities and exchange rate volatility on the intraday behaviour of the 15-minute JPY/USD exchange rate bid–ask spreads in the Electronic Broking Service (EBS) of electronic brokerage market for the period from 1 January 2003 to 31 December 2005. We find that the exchange rate volatility both significantly and positively affects the bid–ask spreads, while the number of deals and quotation changes negatively affect the bid–ask spreads. These results are similar to those of past studies. We also find that a U-shaped pattern exists in the Tokyo trading hours and an inverted U-shaped pattern in the London trading hours, in addition to a round clock inverted U-shaped pattern of spread volatility. This inverted U-shaped pattern may be caused by unexpected news arrivals. The spread behaviour of the EBS global electronic broking market is not different from that of other electronic interdealer quotation markets and electronic broking markets.

Win or Lose the Battle for Creativity: The Power and Perils of Intergroup Competition

Integrating and refining social interdependence theory and structural adaptation theory, we examined the effects of intergroup competition on the creativity of 70 four-person groups engaged in two idea generation tasks. We manipulated both group membership change (change, no change) and intergroup competition level (low, intermediate, high). Competition had the expected U-shaped relation with creativity in open (membership change) groups but failed to produce the hypothesized inverted U-shaped pattern in closed (no membership change) groups. In the latter, effects were positive for low to intermediate competition and flat for intermediate to high levels. Within-group collaboration mediated these effects.

Environmental Latecomer's Effects in Developing Countries: The Case of SO2 and CO2 Emissions

Using the analytical framework of the environmental Kuznets curve, this study examines whether developing countries in the world enjoy the latecomer's advantage or suffer the latecomer's disadvantage in the area of environmental management and technology, with a focus on representative environmental indices of sulfur emissions and carbon emissions. The study's two main findings represent clear contrasts in panel estimation results between sulfur emissions and carbon emissions First, sulfur emissions follow the expected inverted U-shape pattern of the environmental Kuznets curve, while carbon emissions show monotonous increasing trends with per capita income in the observed range. Second, sulfur emissions represent the dominance of the latecomer's advantage while carbon emissions reveal that of the latecomer's disadvantage. The contrast in the emission-income patterns appears to come from the difference in the origin of emissions: sulfur emissions mainly from production (emissions from production are easily regulated on the local level), and carbon emissions from both production and consumption (emissions from consumption are easily externalized). In addition, the contrast in the latecomer's effects seems to be related to the degree of maturity in the know-how and technology to abate emissions: prevailing desulfurization and unrestricted "carbon leakage."

Variation in antidiabetic medication intensity among medicare beneficiaries with diabetes mellitus

Background: Recent guidelines for treating older patients with diabetes mellitus (DM) and significant disease burden place less emphasis on glycemic control and stress the potential harms that may arise from adherence to strict regimens with antidiabetic medications. However, there are few empirical benchmarks against which clinicians can compare their prescribing practices for patients who have DM and varying levels of comorbidity. Objective: The current study had 2 goals: (1) to provide national estimates showing how the intensity of antidiabetic medication regimens for Medicare beneficiaries with DM varies by level of medical spending (a proxy for overall disease burden); and (2) to identify potential predictive factors associated with the observed differences. Methods: This study analyzed 2002 Medicare Current Beneficiary Survey (MCBS) data to benchmark intensity of antidiabetic medication regimens for Medicare beneficiaries with DM arrayed by decile of cumulative medical care spending. The study involved 3 steps: (1) stratification of the study population into 10 mutually exclusive deciles by cumulative all-source annual medical spending; (2) assessment of the unconditional association between decile assignment and intensity of antidiabetic medication use; and (3) identification of mediating factors that differentially explain medication intensity across the spectrum of disease burden. We evaluated 3 outcomes: (1) prevalence of any antidiabetic agent in 2002; (2) annual utilization rates for 5 different classes of oral hypoglycemic agents (sulfonylurea, metformin, thiazolidinedione, α-glucosidase inhibitors, and meglitinides) plus insulins; and (3) counts of annual prescription fills. Results: The final study sample comprised 1956 Medicare beneficiaries representing 23.1% of the MCBS sample after exclusions. We found a pronounced inverted U-shaped pattern in intensity of antidiabetic treatment. Compared with individuals in the group with the highest prevalence of antidiabetic use (decile 7), the unadjusted treatment odds ratios were 0.40 in decile 1 (95% CI, 0.26–0.60) and 0.54 in decile 10 (95% CI, 0.36–0.81). We found similar patterns in the complexity of drug regimens and numbers of antidiabetic prescriptions filled among users. Controlling for disease severity and other factors eliminated the inverted U-shaped pattern among higher cost beneficiaries but not for those in the lower spending deciles. Conclusions: This national study found that high-cost Medicare beneficiaries with DM received substantially less intensive antidiabetic regimens compared with those incurring more modest medical expenditures in 2002. Longitudinal analysis is necessary to determine whether this finding indicates suboptimal therapy or has a more benign explanation. However, the magnitude of the association warrants the attention of clinicians who treat elderly and disabled diabetic patients with high disease burden.

Rewarding effects of 3,4-methylenedioxymethamphetamine (“Ecstasy”) in dominant and subordinate OF-1 mice in the place preference conditioning paradigm

We tested the ability of 3,4-methylenedioxymethamphetamine (MDMA) to induce conditioned place preference (CPP) in dominant and subordinate OF-1 mice subjected to cohabitation and repeated sessions of agonistic confrontation, as well as in non-confronted mice. We selected doses of MDMA (2, 6, 10 mg/kg) previously reported to induce CPP in mice and we measured expression of c-Fos evoked by the treatments in non-confronted mice. MDMA induced c-Fos protein in several corticolimbic regions involved in drug-induced reward. Mice were exposed to brief sessions of agonistic confrontation on 5 consecutive days. Determinations of circulating hormones and drug conditioning tests were carried out on completion of the encounters. The results of hormone assays indicated that dominant mice had higher serum concentrations of testosterone, but lower levels of corticosterone, than submissive mice. Post-conditioning tests after drug conditioning (4 injections of MDMA or saline on alternate days) showed that MDMA significantly produced CPP at doses of 2 and 6 mg/kg, but not at 10 mg/kg, an inverted U-shaped pattern of conditioning that was invariable in non-confronted, dominant and subordinate mice. These results demonstrate that the endocrine and behavioural correlates linked to social status and social stress in mice are not paralleled by significant changes in the rewarding efficacy of MDMA in the CPP paradigm under the specific conditions tested.