The gap between experts, farmers and non-farmers on perceived environmental vulnerability and the influence of values and beliefs.

Science has played a mixed role in guiding conservation and sustainability-oriented decision-making by individuals, policymakers, institutions, and governments. Not all science-based conservation and sustainability initiatives that address issues facing humanity and ecosystems and global problems have gained public support. Conservation decisions and policy prescriptions are and may be based on perceptions about and experiences with the environment, local land use, and ecosystems that may not align with or be grounded in science or evidence from experts in the field. Values, beliefs, and perceptions associated with nature play a critical role in how individuals view biodiversity conservation, sustainability, and natural resource management. This study first examines the gap between experts (scientists and other field experts) and the public (farmers and non-farmers) about the state of water and land resources, wildlife and associated habitats, and aquatic biodiversity in the Smoky Hill River Watershed in western Kansas. Second, the study examines the role that values and beliefs play in shaping environmental perceptions for farmers and non-farmers. Analysis confirms that a gap between experts and farmers/non-farmers does exist, especially with respect to the state of the Ogallala Aquifer, playas, rivers and streams, lakes and reservoirs, native grasslands, wildlife habitats, farmland, native fish populations, and wildlife species. Ordered-logistic regression analyses, meanwhile, indicate that farmer and non-farmer perceptions about the state of the local environment are influenced by traditional and self-interested values, as well as environmental values and beliefs, but less so by religiosity and political ideology. Despite broad takeaways, results exhibited heterogeneity across the farmer and non-farmer subpopulations. If environmental professionals cannot align ecological data, stakeholders' values/perceptions, and policies, then the existing body of technical research and management on sustainability in natural and social sciences may be of little value.

Estimating environmental vulnerability in the Cerrado with machine learning and Twitter data.

Estimating vulnerability is critical to understand human-induced influenceimpacts on the environmental system. The purpose of the current study was to integrate machine learning algorithm and Twitter data to estimate environmental vulnerability in the Brazilian Cerrado for the years 2011 and 2016. We first selected six exposure indicators and five sensitivity indicators to build an environmental vulnerability model and applied an Autoencoder algorithm to find the representation of exposure and sensitivity, respectively. Then the Displaced Ideal method was used to estimate environmental vulnerability. Finally, related historical Twitter data was mined from these two years to validate the results. The findings showed that the percent of land classified as areas of low, medium and high environmental vulnerability were 6.72%, 34.85%, and 58.44% in 2011 and 3.45%, 33.68% and 62.87% in 2016, respectively and most high environmental vulnerability areas were in the Southern Cerrado. Moreover, the Twitter data results showed that more than 85% of tweets occurred in the areas considered as high environmental vulnerability class. The work revealed that the Autoencoder algorithm can be used for environmental assessment, and the social media data has potential to effectively analyze the relationship between human activity and the environment. Although the study provided a novel perspective to estimate environmental vulnerability at a regional scale, it was necessary to develop a more comprehensive indicator system that can improve model performance in the future.

Model approaches to estimate spatial distribution of bee species richness and soybean production in the Brazilian Cerrado during 2000 to 2015.

Agricultural expansion as a main human activity has affected pollinator's habitat, causing spatial distribution changes. Meanwhile, pollinators still provide pollination service to improve crop production. However, their spatial response is unclear because of environmental changes. This study sought to estimate spatial distribution of crop production and pollinator's richness, which can provide insights as to how they interact with the environment. We acquired environmental variables from remote sensing images and used a stacked species distribution model to predict selected bee species richness and a crop simulation model to simulate and calculate soybean production at a regional scale in the Cerrado for the period 2000-2015. Then, we analyzed their potential relationship. The results showed that higher selected bee species richness and higher soybean production occurred in the southern Cerrado. From 2000/08 to 2008/15 period, the selected bee species richness significantly decreased in the western part of the state of Bahia, the state of Goiás, and the northern region of the state of Minas Gerais; while soybean production increased in the states of Mato Grosso, Goiás, Bahia, and Tocantins. Correlation results of selected bee species richness and soybean production showed that they do not follow a linear relationship during the study period. Our findings indicate that the modeling method we proposed is robust to estimate spatial distribution of bee species richness and soybean production in the Cerrado at the regional scale and that the environment has a stronger influence on selected bee species richness than on soybean production. Moreover, climate effects and agricultural expansion are the main factors that affect their spatial distribution and interaction. Finally, our methodology provides a novel spatial perspective to analyze the relationship between pollinator and agricultural expansion corresponding with the environment, but future work is needed to collect a more comprehensive data set to improve model results.

Testing Luminescence Dating Methods for Small Samples from Very Young Fluvial Deposits.

The impetus behind this study is to understand the sedimentological dynamics of very young fluvial systems in the Amazon River catchment and relate these to land use change and modern analogue studies of tidal rhythmites in the geologic record. Initial quartz optically stimulated luminescence (OSL) dating feasibility studies have concentrated on spit and bar deposits in the Rio Tapajós. Many of these features have an appearance of freshly deposited pristine sand, and these observations and information from anecdotal evidence and LandSat imagery suggest an apparent decadal stability. The characteristics of OSL from small (~5 cm) sub-samples from ~65 cm by ~2 cm diameter vertical cores are quite remarkable. Signals from medium-sized aliquots (5 mm diameter) exhibit very high specific luminescence sensitivity, have excellent dose recovery and recycling, essentially independent of preheat, and show minimal heat transfer even at the highest preheats. These characteristics enable measurement of very small signals with reasonable precision and, using modified single-aliquot regenerative-dose (SAR) approaches, equivalent doses as low as ~4 mGy can be obtained. Significant recuperation is observed for samples from two of the study sites and, in these instances, either the acceptance threshold was increased or growth curves were forced through the origin; recuperation is considered most likely to be a measurement artefact given the very small size of natural signals. Dose rates calculated from combined inductively coupled plasma mass spectrometry/inductively coupled plasma optical emission spectrometry (ICP-MS/ICP-OES) and high-resolution gamma spectrometry range from ~0.3 to 0.5 mGya-1, and OSL ages for features so far investigated range from 13 to 34 years to several 100 years. Sampled sands are rich in quartz and yields of 212-250 µm or 250-310 µm grains indicate high-resolution sampling at 1-2 cm intervals is possible. Despite the use of medium-sized aliquots to ensure the recovery of very dim natural OSL signals, these results demonstrate the potential of OSL for studying very young active fluvial processes in these settings.

Evaluating environmental change and behavioral decision-making for sustainability policy using an agent-based model: A case study for the Smoky Hill River Watershed, Kansas.

Sustainability has been at the forefront of the environmental research agenda of the integrated anthroposphere, hydrosphere, and biosphere since the last century and will continue to be critically important for future environmental science. However, linking humans and the environment through effective policy remains a major challenge for sustainability research and practice. Here we address this gap using an agent-based model (ABM) for a coupled natural and human systems in the Smoky Hill River Watershed (SHRW), Kansas, USA. For this freshwater-dependent agricultural watershed with a highly variable flow regime influenced by human-induced land-use and climate change, we tested the support for an environmental policy designed to conserve and protect fish biodiversity in the SHRW. We develop a proof of concept interdisciplinary ABM that integrates field data on hydrology, ecology (fish richness), social-psychology (value-belief-norm) and economics, to simulate human agents' decisions to support environmental policy. The mechanism to link human behaviors to environmental changes is the social-psychological sequence identified by the value-belief-norm framework and is informed by hydrological and fish ecology models. Our results indicate that (1) cultural factors influence the decision to support the policy; (2) a mechanism modifying social-psychological factors can influence the decision-making process; (3) there is resistance to environmental policy in the SHRW, even under potentially extreme climate conditions; and (4) the best opportunities for policy acceptance were found immediately after extreme environmental events. The modeling approach presented herein explicitly links biophysical and social science has broad generality for sustainability problems.

Emotional dampening in persons with elevated blood pressure: affect dysregulation and risk for hypertension.

BACKGROUND: Persons with higher blood pressure have emotional dampening in some contexts. This may reflect interactive changes in central nervous system control of affect and autonomic function in the early stages of hypertension development. PURPOSE: The purpose of this study is to determine the independence of cardiovascular emotional dampening from alexithymia to better understand the role of affect dysregulation in blood pressure elevations. METHODS: Ninety-six normotensives were assessed for resting systolic and diastolic (DBP) blood pressure, recognition of emotions in faces and sentences using the Perception of Affect Task (PAT), alexithymia, anxiety, and defensiveness. RESULTS: Resting DBP significantly predicted PAT emotion recognition accuracy in men after adjustment for age, self-reported affect, and alexithymia. CONCLUSIONS: Cardiovascular emotional dampening is independent of alexithymia and affect in men. Dampened emotion recognition could potentially influence interpersonal communication and psychosocial distress, thereby further contributing to BP dysregulation and increased cardiovascular risk.

Economic linkages to changing landscapes.

Many economic processes are intertwined with landscape change. A large number of individual economic decisions shape the landscape, and in turn the changes in the landscape shape economic decisions. This article describes key research questions about the economics of landscape change and reviews the state of research knowledge. The rich and varied economic-landscape interactions are an active area of research by economists, geographers, and others. Because the interactions are numerous and complex, disentangling the causal relationships in any given landscape system is a formidable research challenge. Limited data with mismatched temporal and spatial scales present further obstacles. Nevertheless, the growing body of economic research on these topics is advancing and shares fundamental challenges, as well as data and methods, with work in other disciplines.

Absorption in self-selected activities is associated with lower ambulatory blood pressure but not for high trait ruminators.

BACKGROUND: A range of nonpharmacological interventions (e.g., meditation) have positive effects on blood pressure (BP) but tend to have poor adherence. These interventions may lower BP partly by absorbing and directing attention away from one's negative thoughts. We hypothesized that recurring self-selected activities (SSAs) that are attentionally absorbing may similarly lower BP. We examined the effect of reported engagement in SSAs during the previous month prior to participation on ambulatory BP (ABP) and whether those prone to rumination were less likely to show these effects. METHODS: Participants (n = 38) reported engagement in SSAs and how absorbing they were, responded to trait rumination and perceived stress questionnaires, wore an ABP monitor for 24 hours, and at each ABP measurement answered electronic diary questions assessing activity levels, affect, social interactions, and caffeine and tobacco use. RESULTS: Regression analyses tested whether the reported absorption of SSAs, trait rumination, and their interaction predicted daytime and nighttime systolic and diastolic ABP. Greater absorption predicted lower daytime and nighttime ABP (bs = -18.83 to -8.79; Ps < .05), but this relationship was moderated by trait rumination (bs = 3.72 to 9.97; Ps < .05). Follow-up analyses revealed that absorption was unrelated to ABP for those with high trait rumination but that more absorption predicted lower ABP for those less prone to rumination. CONCLUSIONS: Our results suggest that regular engagement in absorbing SSAs is related to lower ABP. These findings have implications for the development of nonpharmacological interventions and suggest SSAs may serve as an adjuvant intervention strategy to lower BP.

Too much of a good thing?: Positive religious coping predicts worse diurnal salivary cortisol patterns for overwhelmed African American female dementia family caregivers.

OBJECTIVES: Religious coping arguably prevents negative health outcomes for stressed persons. This study examined the moderating role of religious coping (positive, negative, and combined) in the connection of care recipient functional status with diurnal salivary cortisol patterns among dementia family caregivers. METHODS: Thirty African American (AA) female dementia caregivers and 48 AA noncaregivers completed the Religious Coping (RCOPE) scale, the Activities of Daily Living scale, and the Revised Memory and Behavior Problem Checklist (RMBPC) and collected five saliva samples daily (at awakening, 9 A.M., 12 P.M., 5 P.M., and 9 P.M.) for 2 straight days. RESULTS: Hierarchical regression tests with mean diurnal cortisol slope as the outcome illustrated surprisingly that higher combined and positive (but not negative) RCOPE scores were associated with increasingly flatter or worse cortisol slope scores for caregivers (but not noncaregivers). Of note, the RCOPE by RMBPC interaction was significant. Among caregivers who reported higher RMBPC scores, higher combined and positive (but not negative) RCOPE scores were unexpectedly associated with increasingly flatter cortisol slopes. CONCLUSIONS: These results extend current findings by showing that being AA, a caregiver, and high in positive religious coping may predict increased daily stress responses, mainly for those with higher patient behavioral problems. Because religious coping is a central coping strategy for AA caregivers, it is vital that epidemiologic assessments of religious coping in health and aging as well as tailored interventions focus on the unique reasons for this disparity.

Cardiovascular-emotional dampening: the relationship between blood pressure and recognition of emotion.

OBJECTIVE: Persons with elevated blood pressure (BP) show dampened emotional responses to affect-laden stimuli. We sought to further examine cardiovascular-emotional dampening by examination of the relationship between resting hemodynamic measures and recognition of emotion in an African American community-based sample. METHODS: Participants were 106 African American men and women (55 women; mean age = 52.8 years), mainly low in socioeconomic status, and part of the Healthy Aging in Nationally Diverse Longitudinal Samples pilot study. Participants evaluated emotional expressions in faces and sentences using the Perception of Affect Test (PAT). Resting BP, total peripheral resistance (TPR), cardiac output, and heart rate were obtained continuously using a Portapres BP monitor. RESULTS: Total PAT scores were inversely related to systolic (r = -0.30) and diastolic (r = -0.24) BPs, TPR (r = -0.36), and age (r = -0.31; p values < .01) and were positively related to cardiac output (r = 0.27) and education (r = 0.38; p values < .01), as well as with mental state (r = 0.25) and body mass index (r = -0.20; p values < .05). Accuracy of emotion recognition on the PAT tasks remained inversely related to TPR and BP after adjustment for demographic variables, medication, mental state, and body mass index. CONCLUSIONS: Elevated BP and TPR were associated with reduced perception of affect. TPR was the most consistent independent hemodynamic correlate of emotional dampening for the PAT scores. These results suggest potentially important links among central nervous system regulation of emotions, hemodynamic processes, and hypertension development.

How much striving is too much? John Henryism active coping predicts worse daily cortisol responses for African American but not white female dementia family caregivers.

INTRODUCTION: The John Henryism active coping (JHAC) hypothesis suggests that striving with life challenges predicts increased risk for cardiovascular disease for those with scarce coping resources. This study examined the moderating role of JHAC in the associations of 1) caregiver status and 2) care recipient functional status with diurnal salivary cortisol patterns among 30 African Americans (AAs) and 24 white female dementia caregivers and 63 noncaregivers (48 AAs). METHODS: Caregiver participants completed the JHAC-12 scale, Activities of Daily Living (ADL) scale, and Revised Memory and Behavior Problem checklist (RMBPC) and collected five saliva samples daily (at awakening, 9 A.M., 12 P.M., 5 P.M., and 9 P.M.) for 2 successive days. RESULTS: Univariate analysis of variance tests with mean diurnal cortisol slope as the outcome illustrated that among AA caregivers, higher JHAC scores were related to flatter (or more dysregulated) cortisol slopes. The JHAC by ADL and JHAC by RMBPC interactions were each significant for AA caregivers. Among AA caregivers who reported higher ADL and RMBPC scores, higher JHAC scores were associated with flatter cortisol slopes. CONCLUSIONS: These findings extend recent studies by showing that being AA, a caregiver, and high in JHAC may elevate the risk for chronic disease, especially for those with higher patient ADL and behavioral problems. Thus, it is imperative that interventions appreciate the pernicious role of high-effort coping style, especially for AA caregivers, to minimize the stressful side effects of patient ADL and memory and behavioral problems for the caregiver.

Neurologic complications of arteriovenous malformation embolization using liquid embolic agents.

BACKGROUND AND PURPOSE: Embolization of arteriovenous malformations (AVMs) is commonly used to achieve nidal volume reduction before microsurgical resection or stereotactic radiosurgery. The purpose of this study was to examine the overall neurologic complication rate in patients undergoing AVM embolization and analyze the factors that may determine increased risk. MATERIALS AND METHODS: We performed a retrospective review of all patients with brain AVMs embolized at 1 center from 1995 through 2005. Demographics, including age, sex, presenting symptoms, and clinical condition, were recorded. Angiographic factors including maximal nidal size, presence of deep venous drainage, and involvement of eloquent cortex were also recorded. For each embolization session, the agent used, number of pedicles embolized, the percentage of nidal obliteration, and any complications were recorded. Complications were classified as the following: none, non-neurologic (mild), transient neurologic deficit, and permanent nondisabling and permanent disabling deficits. The permanent complications were also classified as ischemic or hemorrhagic. Modified Rankin Scale (mRS) scores were collected pre- and postembolization on all patients. Univariate regression analysis of factors associated with the development of any neurologic complication was performed. RESULTS: Four hundred eighty-nine embolization procedures were performed in 192 patients. There were 6 Spetzler-Martin grade I (3.1%), 26 grade II (13.5%), 71 grade III (37.0%), 57 grade IV (29.7%), and 32 grade V (16.7%) AVMs. Permanent nondisabling complications occurred in 5 patients (2.6%) and permanent disabling complications or deaths occurred in 3 (1.6%). In addition, there were non-neurologic complications in 4 patients (2.1%) and transient neurologic deficits in 22 (11.5%). Five of the 8 permanent complications (2.6% overall) were ischemic, and 3 of 8 (1.6% overall) were hemorrhagic. Of the 178 patients who were mRS 0-2 pre-embolization, 4 (2.3%) were dependent or dead (mRS >2) at follow-up. Univariate analysis of risk factors for permanent neurologic deficits following embolization showed that basal ganglia location was weakly associated with a new postembolization neurologic deficit. CONCLUSION: Embolization of brain AVMs can be performed with a high degree of technical success and a low rate of permanent neurologic complications.

Comparison of arterial compliance indices derived via beat-to-beat blood pressure waveforms: aging and ethnicity.

Reduced arterial compliance has been implicated as a risk factor for future cardiovascular events in hypertensive patients. Recently, several non-invasive techniques have been used to access arterial compliance. However, comparisons of these techniques with older individuals and African-Americans have not been done. In the present study, beat-to-beat blood pressure was examined in 75 males and females (n = 24 old Caucasian; n = 24 young Caucasian; n = 27 African-Americans) who were part of the Baltimore Longitudinal Study of Aging (BLSA). Resting beat-to-beat blood pressure (5 minutes) was assessed using the PORTAPRES Ambulatory Blood Pressure Device. Results indicated that the three-element windkessel and the stroke volume-pulse pressure ratio measures of arterial compliance provide comparable estimates. Specifically, arterial compliance is reduced in the oldest individuals in our sample with young and African-Americans showing higher compliance. These results indicate that the simpler stroke volume-pulse pressure ratio provides reliable estimates of arterial compliance in both older adults and African-Americans. This technique is an excellent means to assess arterial compliance and is a useful measure to determine risk for adverse cardiovascular events.

Perceived racism and cardiovascular reactivity and recovery to personally relevant stress.

This study evaluated cardiovascular responses (CVR) to an active speech task with blatantly discriminatory (BRC) versus neutral (NRC) stimuli and an anger recall task in a sample of Black men (N = 73; age 18 to 47). Diastolic blood pressure scores were higher for NRC versus BRC stimuli during anger recall (p = .05). Moreover, persons in the NRC group who perceived high levels of racism (vs. no racism or BRC group) during active speech showed larger increases in blood pressure across postspeech rest, anger recall, and subsequent rest (p = .03). The notable elevation in CVR in response to an ambiguous event extends current models of racism suggesting that subtle racism is a psychosocial stressor that erodes health through chronically elevated CVR.

Understanding blood pressure variability: spectral indices as a function of gender and age.

Typically, blood pressure variability has been calculated by taking the simple mathematical standard deviations of a collection of discrete blood pressure (BP) measurements. Recently, spectral analytic techniques have been employed to examine beat-to-beat blood pressure variability and the underlying autonomic adjustments associated with the performance of various tasks. In the present study, beat-to-beat blood pressure was examined in 104 older African-Americans males and females who were part of the Healthy Aging in Nationally Diverse Longitudinal Samples (HANDLS) Study. Participants evaluated faces and sentences depicting emotional content and rested before (Baseline) and after (Recovery) the tasks. There were no significant gender effects in any analyses. In addition, there were no significant task effects. However, there was a trend for both low and high frequency systolic blood pressure variability to decrease linearly from baseline, through faces and sentences to recovery. Interestingly, both systolic and diastolic high frequency blood pressure variability was greater in older as compared to younger adults. Increased blood pressure variability has been associated with greater sheer stress and greater end organ damage. These results will explicate the effects of aging on cardiovascular disease risk. Overall, these data indicate that blood pressure variability derived via spectral analytic techniques is a useful tool for understanding cardiodynamics and may provide a more in-depth analysis of blood pressure response.

Ethnicity, education, and the cortisol response to awakening: a preliminary investigation.

OBJECTIVE: To explore the associations among ethnicity, educational attainment, and cortisol secretion. DESIGN: Participants include 63 white (n = 31) and African-American (n = 32) adult men and women. Subjects provided salivary cortisol samples immediately upon awakening and again, 30 minutes later. RESULTS: Analyses adjusted for relevant covariates revealed a steeper awakening response among whites with higher education compared to other groups. Cortisol levels were significantly lower among African-American participants with lower levels of education. All effects were independent of perceived stress. CONCLUSIONS: These preliminary findings demonstrate significant ethnic and education-related differences in awakening cortisol secretion responses. Our data highlight the importance of considering ethnicity and the moderating effects of social class when examining the associations among social contextual factors and cortisol secretion.

Kullback-Leibler clustering of continuous wavelet transform measures of heart rate variability.

Power spectral analysis of beat-to-beat heart rate variability (HRV) has provided a useful means of understanding the interplay between autonomic and cardiovascular functionality. Despite their utility, commonly employed frequency-domain techniques are limited in their prerequisite for stationary signals and their inability to account for temporal changes in the power spectral and/or frequency properties of signals. The purpose of this study is to develop an algorithm that utilizes continuous wavelet transform (CWT) parameters as inputs to a Kohonen self-organizing map (SOM), providing a method of clustering subjects with similar wavelet transform signatures. Continuous interbeat-intervals were recorded (Portapres monitor at 200 Hz) during a perception of affect test in 79 African-American volunteers (ages 21-83), where after a 5-min baseline, participants evaluated emotional expressions in sentences and pictures of faces, followed by a 5-min recovery. Individual HRV biosignals from each session were pre-processed (artifact replacement and signal resampling at 2 Hz) and a CWT was applied (db9 wavelet basis function over 32 scales). Standard deviations of resulting wavelet coefficients at each scale were calculated, normalized, and used as inputs into a SOM with Kullback-Leibler divergence as the dissimilarity measure used for clustering. Differences in subject demographics between two final clusters were assessed via two-independent-groups t-tests or chi-square or Fisher's exact tests of contingency tables. Significant differences were found for age, initial systolic blood pressure, smoking status, and mean s.d. of coefficients in the high frequency band (0.15-0.4 Hz). These findings may have clinical significance and the developed algorithm provides an alternative means of analyzing HRV data originating from populations with complex covariates.

Low educational attainment, John Henryism, and cardiovascular reactivity to and recovery from personally relevant stress.

OBJECTIVE: The John Henryism hypothesis proposes that a high level of John Henryism (JH: high-effort coping with psychosocial demands) is predictive of hypertension at low but not high socioeconomic status (SES). The objectives of the present study were to determine whether high JH and low SES (education, income, job status, and job strain) were associated with increased cardiovascular responses to laboratory social stressors. METHODS: Subjects were 58 normotensive, healthy black men age 23 to 47 years. The procedure included the completion of psychosocial questionnaires and participation in a psychophysiological reactivity protocol. The reactivity protocol involved the following experimental tasks and associated recovery periods: an active speech task and an anger recall task. Measures of systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), and rate pressure product (RPP) were obtained continuously using a Finapres beat-to-beat blood pressure monitor throughout the reactivity protocol. RESULTS: At high JH, low (compared with high) education level was linked with higher DBP during anger recall and final recovery, higher SBP during final recovery, and higher HR and RPP during speech preparation and final recovery (p <.05). Among subjects with low education, high (vs. low) JH was associated with higher SBP, HR, and RPP during final recovery (p <.05). CONCLUSIONS: John Henryism may increase the risk of cardiovascular disease among people with low education by increased cardiovascular reactivity and prolonged recovery to stress.

Effect of angiotensin-converting enzyme insertion/deletion polymorphism DD genotype on high-frequency heart rate variability in African Americans.

Seventy-nine African-American participants in the Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) pilot study were genotyped for the angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphism and had spectral power of their high-frequency (HF) heart rate variability (HRV) determined by fast-Fourier transformation. HF HRV was highest in II, intermediate in ID, and lowest in DD (II vs DD, p <0.043) genotypes, thus making an association of the ACE I/D DD genotype with decreased HF HRV that is consistent with the hypothesis that the DD genotype confers susceptibility to increased cardiovascular risk. The urban African-American population we studied had a particularly high cardiovascular risk, and these findings suggest that ACE I/D genotypes may modify that risk.