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Monumental roads were constructed during the ninth to thirteenth centuries by the regional society centred on Chaco Canyon in the US Southwest. Here, the authors present new lidar and field documentation of parallel roads at the Gasco Site, which sits within a ritual landscape south of Chaco Canyon. Their findings reveal that the Gasco Road is substantially longer than previously believed and forms alignments between natural springs and towards the winter solstice sunrise over Mount Taylor, a mountain sacred among contemporary Indigenous peoples. These findings highlight the agency of landscapes and skyscapes in structuring ritual practices in ancient societies worldwide.
Contrast-induced encephalopathy (CIE) is an adverse event associated with diagnostic and therapeutic endovascular procedures. Decades of animal and human research support a mechanistic role for pathological blood-brain barrier dysfunction (BBBd). Here, we describe an institutional case series and review the literature supporting a mechanistic role for BBBd in CIE.
Methods:
A literature review was conducted by searching MEDLINE, Web of Science, Embase, CINAHL and Cochrane databases from inception to January 31, 2022. We searched our institutional neurovascular database for cases of CIE following endovascular treatment of cerebrovascular disease during a 6-month period. Informed consent was obtained in all cases.
Results:
Review of the literature revealed risk factors for BBBd and CIE, including microvascular disease, pathological neuroinflammation, severe procedural hypertension, iodinated contrast load and altered cerebral blood flow dynamics. In our institutional series, 6 of 52 (11.5%) of patients undergoing therapeutic neuroendovascular procedures developed CIE during the study period. Four patients were treated for ischemic stroke and two patients for recurrent cerebral aneurysms. Mechanical stenting or thrombectomy were utilized in all cases.
Conclusion:
In this institutional case series and literature review of animal and human data, we identified numerous shared risk factors for CIE and BBBd, including microvascular disease, increased procedure length, large contrast volumes, severe intraoperative hypertension and use of mechanical devices that may induce iatrogenic endothelial injury.
Many individuals with COVID-19 develop mild to moderate physical symptoms that can last days to months. In addition to physical symptoms, individuals with COVID-19 have reported depressive symptoms and cognitive decline, posing a long-term threat to mental health and functional outcomes. Few studies have examined the presence of co-occurring depression and subjective cognitive decline in individuals who tested positive for COVID-19. The current study examined whether having COVID-19 is subsequently associated with greater depressive symptoms and subjective cognitive decline when compared to healthy individuals. Our study also examined differential associations between symptoms of depression and subjective cognitive decline between individuals who have and have never had COVID-19.
Participants and Methods:
Adults (N = 104; mean age = 37 years, 69% female) were recruited online from Ontario and British Columbia, Canada. Participants were categorized into two groups: (1) persons who tested positive for COVID-19 at least three months prior, had been symptomatic, and had not been ventilated (N = 50); and (2) persons who have never been suspected of having COVID-19 (N = 54). The Center for Epidemiological Studies Depression Scale (CES-D) and the Subjective Cognitive Decline Questionnaire (SCD-Q) were administered to both groups as part of a larger clinical neuropsychological evaluation. Two separate linear regression analyses were conducted to examine the association of COVID-19 with depressive symptoms and subjective cognitive decline. A moderation analysis was performed to examine whether depressive symptoms were associated with subjective cognitive decline and the extent to which this differed by group (COVID-19 and controls). Participants’ age, self-reported sex, and history of depression were included as covariates.
Results:
The first regression model explained 17.2% of the variance in CES-D scores. It was found that the COVID-19 group had significantly higher CES-D scores (ß = .20, p = .03). The second regression model explained 35.9% of the variance in SCD-Q scores. Similar to the previous model, it was found that the COVID-19 group had significantly higher SCD-Q scores compared to healthy controls (ß = .22 p = .01). Lastly, the moderation model indicated that higher CES-D scores were associated with higher SCD-Q scores (ß = .43, p < .01), but there was no statistically significant group X CES-D score interaction.
Conclusions:
These findings suggest that individuals who previously experienced a mild to moderate symptomatic COVID-19 infection report greater depressive symptom severity as well as greater subjective cognitive decline. Additionally, while more severe depressive symptoms predicted greater subjective cognitive decline in our sample, the magnitude of this association did not vary between those with and without a previous COVID-19 infection. While the underlying neurobiological and social mechanisms of cognitive difficulties and depressive symptoms in persons who have had COVID-19 have yet to be fully elucidated, our findings highlight treatment for depression and cognitive rehabilitation as potentially useful intervention targets for the post COVID-19 condition.
The Rare and Atypical DIAbetes NeTwork (RADIANT) aims to discover the underlying pathoetiology of atypical diabetes by conducting both genotyping and non-genetic deep phenotyping. While the return of genetic test results in research settings has been investigated, the return of non-genetic results (RoR-NG) has received less attention. We explore the RoR-NG with RADIANT investigators and participants.
Methods/Study Population:
We conducted one-on-one interviews with 10 adult RADIANT participants and 10 RADIANT investigators. Participants also completed two health literacy screening tools and a survey on perspectives regarding return of results (RoR). Investigators completed one survey on experience and confidence in explaining clinical tests utilized in the RADIANT study and another survey on perspectives regarding RoR.
Results:
Most participants were non-Hispanic White. All participants had high scores on health literacy screens. Both RADIANT participants and investigators expressed strong support for RoR-NG. RADIANT participants and investigators acknowledged the different roles and responsibilities between research and clinical care for interpreting and acting on non-genetic results. However, the lines between clinical care and research in returning and acting on results were often blurred by both participants and investigators.
Discussion/Significance:
Our study provides important insight into how both investigators and participants simultaneously distinguish and blur clinical and research roles and responsibilities when discussing non-genetic research results and the return of these results. Further study should engage individuals from diverse racial and ethnic backgrounds and with varying levels of health literacy to understand how best to support all participants when returning research results.
Few phrases in the discourse of the Chinese Communist Party (CCP) have proven as durable and pliable as “seeking truth from facts.” The phrase was first used by Mao Zedong in the 1930s as a way to legitimate the CCP's departure from Stalinist direction, and it was later mobilized by Deng Xiaoping to signal a shift from Maoism toward new avenues of policy experimentation. In recent years, as rising tensions in the US-China relationship have produced a burgeoning literature that seeks to understand and interpret Beijing's intentions for a Western audience, the phrase has become as applicable to the study of China as it has long been to the governance of China. This is not merely because the People's Republic of China (PRC) provides an endless source of raw material for speculation and analysis, obscured behind a veil of obfuscation, censorship, and propaganda constructed by the world's largest and most powerful political party. It is also because the stakes of the debate—coming at a time when the role of the West in general, and the United States in particular, has been thrown into doubt by social division, political dysfunction, and economic decline—seem to provide grounds for doubting the motives of anyone who aspires to take a stand on such a crucial yet ambiguous question as the true nature of CCP rule. With so many facts to choose from, how are we to know which will produce the right truths, and more importantly, who is doing the choosing and why?
Many players know that the secret of winning the game of nim (and other “impartial” combinatorial games) is to write the sizes of the game’s piles in base 2 and then add them together without carry. The proof of this well-known procedure (described below) is both straightforward and convincing. Nonetheless, the procedure still appears magical, as though a rabbit has been pulled out of a hat. Astute students (and frustrated professors) often ask why the winning strategy for such games involves base 2, and not some other base. After all, nothing about the game of nim itself – the game rules, the configuration of the tokens, etc. – provides any hints about the origin of base 2 in this setting. Minimal insight is offered by most published proofs, which themselves tend to either appear almost wizardly in nature (i.e. assume the base-2 method and show that it miraculously solves the problem) or employ combinatorial arguments that supply little abstract intuition (at least to the authors of this article).
In Chapter 3, we move to a semiclassical treatment (quantum theory) of light absorption and scattering, specifically from atoms. We start with a description of how lidar measures Doppler shift, and the fundamental difference between the measurement when the laser is in resonance with an atomic transition (resonant) and when it is not (nonresonant). We follow with a treatment of quantum polarizability and the resulting absorption cross section, leading to the differential resonance scattering cross section and its contrast with the classical result. After quantum polarizability, we demonstrate the radiation pattern of coherently excited atoms. This takes us to an interpretation of the Hanle Effect. Following these descriptions of the phenomena that impact resonance lidar, we extend our understanding by closing the chapter with an overview of the rudimentary physics of sodium laser guide stars.
In Chapter 5, having introduced the physics behind light scattering, we present the lidar equation. This sets the stage for consideration and simulation of various types of lidar. These include the following broadband lidars: Rayleigh–Mie, polarization, vibrational Raman and fluorescence, and differential absorption. They also include high–spectral resolution (narrowband) lidars: Lidar ratio and aerosol properties, temperature profiling by integration Rayleigh+Raman, temperature profiling with rotational Raman and Cabannes scattering, Rayleigh–Mie wind profiling, and mesopause–region resonance fluorescence wind+temperature profiling.
In Chapter 7, we present lidars for profiling atmospheric parameters such as aerosol optical properties, temperatures, and winds. We start with a description of methods for profiling the lidar aerosol-molecular ratio and determining aerosol optical properties. We present and compare techniques for these measurements, including Rayleigh and vibrational Raman integration, rotational Raman technique, and the use of multiple receiver channels with custom-built interference filters. We follow with a description of high-spectral resolution lidar (HSRL), including a detailed discussion of notch (atomic or molecular vapor) filters in the Cabannes scattering detection channels and what is required to make an “ideal” or near-ideal filter. From there, we describe wind profiling methods using Cabannes–Mie scattering, comparing coherent versus incoherent lidars. For HSRL, we describe a near-ideal filter based on absorption in potassium vapor at 770 nm. Following parameter profiling with Cabannes–Mie lidar, we close by describing temperature and wind profiling with laser-induced fluorescence. Here, we focus on Na and Fe lidars. We give summaries of daylight measurements and data processing algorithms, including uncertainty in measurements. We close by discussing scientific contributions by and challenges for these lidars.
In Chapter 2, we present classical light scattering theory. We show the classical electric dipole and how it leads to a model of atomic polarizability and differential scattering cross section. This leads us to the two principal divisions of atomic and molecular scattering, resonant and nonresonant. From here, we close with the causes of broadening of the scattering spectrum, as compared to the laser excitation.
Chapter 1 is an introduction, reviewing the current state of instructional texts on atmospheric lidar. We point to the lack of a treatment of light scattering as employed by lidar from fundamental physics, the motivation for writing this book. We then summarize the scattering processes, Rayleigh, Raman, Mie, and fluorescence, that enable us to probe the state of the atmosphere with lidar. We include a description of the structure and content of the chapters that follow.