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A Look at the Relationship between the Large-Scale Tropospheric Static Stability and the Tropical Cyclone Maximum Intensity
Get PDFVarious modeling and observational studies have suggested that tropical cyclone (TC) intensity tends to increase in the future due to projected warmer sea surface temperature (SST). This study examines the effects of the tropospheric stratification that could potentially offset the direct increase of TC intensity associated with the warmer SST. Using reanalysis datasets and TC records in the northwestern Pacific and the North Atlantic basins, it is shown that there exists a consistently negative correlation between the annually averaged TC intensity and the basinwide average of the tropospheric static stability. This negative correlation is more robust in the northwestern Pacific basin when using the TC lifetime maximum intensity but is somewhat less significant in the North Atlantic basin. Further separation of the troposphere into a lower (1000–500 hPa) and an upper layer (500–200 hPa) reveals that it is the upper-tropospheric static stability that plays a more dominant role in governing the TC intensity variability. The negating effects of a stable troposphere on TC intensity as found in this study suggest a partial offset of the projected increase in the TC potential intensity due to the future warmer SST. Thus, the tropospheric static stability is one of the key large-scale factors that need to be properly taken into account in studies of long-term TC intensity change
Spatial Temporal Analysis of Fieldwise Flow in Microvasculature
Get PDFChanges in blood flow velocity and distribution are vital in maintaining tissue and organ perfusion in response to varying cellular needs. Further, appearance of defects in microcirculation can be a primary indicator in the development of multiple pathologies. Advances in optical imaging have made intravital microscopy (IVM) a practical approach, permitting imaging at the cellular and subcellular level in live animals at high-speed over time. Yet, despite the importance of maintaining adequate tissue perfusion, spatial and temporal variability in capillary flow is seldom documented. In the standard approach, a small number of capillary segments are chosen for imaging over a limited time. To comprehensively quantify capillary flow in an unbiased way we developed Spatial Temporal Analysis of Fieldwise Flow (STAFF), a macro for FIJI open-source image analysis software. Using high-speed image sequences of full fields of blood flow within capillaries, STAFF produces images that represent motion over time called kymographs for every time interval for every vascular segment. From the kymographs STAFF calculates velocities from the distance that red blood cells move over time, and outputs the velocity data as a sequence of color-coded spatial maps for visualization and tabular output for quantitative analyses. In normal mouse livers, STAFF analyses quantified profound differences in flow velocity between pericentral and periportal regions within lobules. Even more unexpected are the differences in flow velocity seen between sinusoids that are side by side and fluctuations seen within individual vascular segments over seconds. STAFF is a powerful new tool capable of providing novel insights by enabling measurement of the complex spatiotemporal dynamics of capillary flow
The Regional Hydroclimate Response to Stratospheric Sulfate Geoengineering and the Role of Stratospheric Heating
Get PDFGeoengineering methods could potentially offset aspects of greenhouse gas‐driven climate change. However, before embarking on any such strategy, a comprehensive understanding of its impacts must be obtained. Here, a 20‐member ensemble of simulations with the Community Earth System Model with the Whole Atmosphere Community Climate Model as its atmospheric component is used to investigate the projected hydroclimate changes that occur when greenhouse gas‐driven warming, under a high emissions scenario, is offset with stratospheric aerosol geoengineering. Notable features of the late 21st century hydroclimate response, relative to present day, include a reduction in precipitation in the Indian summer monsoon, over much of Africa, Amazonia and southern Chile and a wintertime precipitation reduction over the Mediterranean. Over most of these regions, the soil desiccation that occurs with global warming is, however, largely offset by the geoengineering. A notable exception is India, where soil desiccation and an approximate doubling of the likelihood of monsoon failures occurs. The role of stratospheric heating in the simulated hydroclimate change is determined through additional experiments where the aerosol‐induced stratospheric heating is imposed as a temperature tendency, within the same model, under present day conditions. Stratospheric heating is found to play a key role in many aspects of projected hydroclimate change, resulting in a general wet‐get‐drier, dry‐get‐wetter pattern in the tropics and extratropical precipitation changes through midlatitude circulation shifts. While a rather extreme geoengineering scenario has been considered, many, but not all, of the precipitation features scale linearly with the offset global warming
Timescale for Detecting the Climate Response to Stratospheric Aerosol Geoengineering
Get PDFStratospheric aerosol geoengineering could be used to maintain global mean temperature despite increased atmospheric greenhouse gas (GHG) concentrations, for example, to meet a 1.5 or 2 °C target. While this might reduce many climate change impacts, the resulting climate would not be the same as one with the same global mean temperature due to lower GHG concentrations. The primary question we consider is how long it would take to detect these differences in a hypothetical deployment. We use a 20‐member ensemble of stratospheric sulfate aerosol geoengineering simulations in which SO2 is injected at four different latitudes to maintain not just the global mean temperature, but also the interhemispheric and equator‐to‐pole gradients. This multiple‐latitude strategy better matches the climate changes from increased GHG, while the ensemble allows us both to estimate residual differences even when they are small compared to natural variability and to estimate the statistics of variability. We first construct a linear emulator to predict the model responses for different scenarios. Under an RCP4.5 scenario in which geoengineering maintains a 1.5 °C target (providing end‐of‐century cooling of 1.7 °C), the projected changes in temperature, precipitation, and precipitation minus evaporation (P − E) at a grid‐scale are typically small enough that in many regions the signal‐to‐noise ratio is still less than one at the end of this century; for example, for P − E, only 30% of the land area reaches a signal‐to‐noise ratio of one. These results provide some context for the projected magnitude of climate changes associated with a limited deployment of stratospheric aerosol cooling
Interpretation of main effects in the presence of non-significant interaction effects
Get PDFModerated regression models include an interaction, or product term, and can be used to assess whether the relationship between a given independent variable (IV) and a dependent variable (DV) depends on a third moderator variable (MV). If the moderation effect is significant, researchers recommend either ignoring main effects completely, or carefully interpreting them as conditional effects. However, when the moderation effect is not significant, this implies that the typical interpretation of main effects as average effects is appropriate. The present study challenges this claim since lack of significance may be due to lack of power rather than to no true population effect. To explore this idea, a simulation study is conducted and analytic illustration provided. Results indicate that when a true moderation effect exists, it may not be detected, implying the potential for misleading interpretation of main effects. To guard against this, applied researchers are encouraged to conduct power analyses prior to a moderation study; to mean-center predictors; to consider exploring the main-effects-only model by omitting the interaction effect; and to consider information criteria approaches to testing effects
Understanding Illicit Insemination and Fertility Fraud, From Patient Experience to Legal Reform
Get PDFRecently, several cases have been filed in North America and Europe alleging that fertility physicians inseminated former patients with their own sperm only to have this conduct come to light decades later when their unsuspecting adult children use direct-to-consumer genetic tests and learn that they are not biologically related to their fathers and often that they have multiple half-siblings. For instance, Donald Cline of Indianapolis, Indiana, has over sixty doctor-conceived children, with more continuing to come forward. Although these cases induce disgust, it has thus far proven difficult to hold these physicians legally accountable because their conduct falls within gaps in existing civil and criminal laws. This Article explores the legal contours of fertility fraud cases involving illicit physician inseminations, explaining why it falls through gaps in existing criminal and civil law and why it is essential to take whatever measures are necessary to hold physicians accountable. Part I discusses six physicians who have thus far faced criminal or civil charges for their conduct in North America and explores how artificial insemination has long been a stigmatized practice cloaked in secrecy. Part II discusses how fertility fraud violates various ethical and legal interests of female and male former patients and their doctor-conceived children. Part III assesses how Cline’s illicit inseminations affected parents and progeny and how Cline’s progeny learn of new genetic connections, what they think of Cline and his motivations, how they derive support from one another, their reactions to criminal proceedings against Cline, and why they regard a legislative “fertility fraud” bill as an ideal outcome. Part IV analyzes why it is difficult to hold physicians criminally and civilly liable under existing law, including excerpts from an interview with the prosecutor in the Cline case. Finally, Part V discusses successful efforts to overcome these difficulties through passing fertility fraud legislation in Indiana and Texas
Revisiting phonetic integration in bilingual borrowing
Get PDFThis article investigates whether speakers marshal phonetic integration as a strategy to distinguish language-contact phenomena. Systematic comparison of the behavior of individuals, diagnostics, and language-mixing types (code-switches, established loanwords, and nonce borrowings) reveals variability at every level of the adaptation process, providing strong evidence that bilinguals do not phonetically distinguish other-language words, nonce or dictionary-attested, in a uniform way. This is in striking contrast to the community-wide morphosyntactic treatment they afford this same material when borrowing it: immediate, quasi-categorical, and consistent. This confirms that phonetic and morphosyntactic integration are independent. Only the latter is a reliable metric for distinguishing language-mixing types
Vocal tract shape and acoustic adjustments of children during phonation into narrow flow-resistant tubes
Get PDFThe goal of the study is to quantify the salient vocal tract acoustic, subglottal acoustic, and vocal tract physiological characteristics during phonation into a narrow flow-resistant tube with 2.53 mm inner diameter and 124 mm length in typically developing vocally healthy children using simultaneous microphone, accelerometer, and 3D/4D ultrasound recordings. Acoustic measurements included fundamental frequency (), first formant frequency (), second formant frequency (), first subglottal resonance (), and peak-to-peak amplitude ratio (:). Physiological measurements included posterior tongue height (D1), tongue dorsum height (D2), tongue tip height (D3), tongue length (D4), oral cavity width (D5), hyoid elevation (D6), pharynx width (D7). All measurements were made on eight boys and ten girls (6–9 years) during sustained /o:/ production at typical pitch and loudness, with and without flow-resistant tube. Phonation with the flow-resistant tube resulted in a significant decrease in , , and : and a significant increase in D2, D3, and . A statistically significant gender effect was observed for D1, with D1 higher in boys. These findings agree well with reported findings from adults, suggesting common acoustic and articulatory mechanisms for narrow flow-resistant tube phonation. Theoretical implications of the findings are discussed
Tropical widening: From global variations to regional impacts
Get PDFOver the past 15 years, numerous studies have suggested that the sinking branches of Earth’s Hadley circulation and the associated subtropical dry zones have shifted poleward over the late twentieth century and early twenty-first century. Early estimates of this tropical widening from satellite observations and reanalyses varied from 0.25° to 3° latitude per decade, while estimates from global climate models show widening at the lower end of the observed range. In 2016, two working groups, the U.S. Climate Variability and Predictability (CLIVAR) working group on the Changing Width of the Tropical Belt and the International Space Science Institute (ISSI) Tropical Width Diagnostics Intercomparison Project, were formed to synthesize current understanding of the magnitude, causes, and impacts of the recent tropical widening evident in observations. These working groups concluded that the large rates of observed tropical widening noted by earlier studies resulted from their use of metrics that poorly capture changes in the Hadley circulation, or from the use of reanalyses that contained spurious trends. Accounting for these issues reduces the range of observed expansion rates to 0.25°–0.5° latitude decade—within the range from model simulations. Models indicate that most of the recent Northern Hemisphere tropical widening is consistent with natural variability, whereas increasing greenhouse gases and decreasing stratospheric ozone likely played an important role in Southern Hemisphere widening. Whatever the cause or rate of expansion, understanding the regional impacts of tropical widening requires additional work, as different forcings can produce different regional patterns of widening