Modelling Subarctic watershed dissolved organic carbon response to hydroclimatic regime.

Shifts in hydroclimatic regimes associated with global climate change may impact freshwater availability and quality. In high latitudes of the northern hemisphere, where vast quantities of carbon are stored terrestrially, explaining landscape-scale carbon (C) budgets and associated pollutant transfer is necessary for understanding the impact of changing hydroclimatic regimes. We used a dynamic modelling approach to simulate streamflow, DOC concentration, and DOC export in a northern Canadian catchment that has undergone notable climate warming, and will continue to for the remainder of this century. The Integrated Catchment model for Carbon (INCA-C) was successfully calibrated to a multi-year period (2012-2016) that represents a range in hydrologic conditions. The model was subsequently run over 30-year periods representing baseline and two future climate scenarios. Average discharge is predicted to decrease under an elevated temperature scenario (22-27 % of baseline) but increase (116-175 % of baseline) under an elevated temperature and precipitation scenario. In the latter scenario the nival hydroclimatic regime is expected to shift to a combined nival and pluvial regime. Average DOC flux over 30 years is predicted to decrease (24-27 % of baseline) under the elevated temperature scenario, as higher DOC concentrations are offset by lower runoff. Under the elevated temperature and precipitation scenario, results suggest an increase in carbon export of 64-81 % above baseline. These increases are attributed to greater connectivity of the catchment. The largest increase in DOC export is expected to occur in early winter. These predicted changes in DOC export, particularly under a climate that is warmer and wetter could be part of larger ecosystem change and warrant additional monitoring efforts in the region.

Assessment of dispersion of airborne particles of oral/nasal fluid by high flow nasal cannula therapy.

BACKGROUND: Nasal High Flow (NHF) therapy delivers flows of heated humidified gases up to 60 LPM (litres per minute) via a nasal cannula. Particles of oral/nasal fluid released by patients undergoing NHF therapy may pose a cross-infection risk, which is a potential concern for treating COVID-19 patients. METHODS: Liquid particles within the exhaled breath of healthy participants were measured with two protocols: (1) high speed camera imaging and counting exhaled particles under high magnification (6 participants) and (2) measuring the deposition of a chemical marker (riboflavin-5-monophosphate) at a distance of 100 and 500 mm on filter papers through which air was drawn (10 participants). The filter papers were assayed with HPLC. Breathing conditions tested included quiet (resting) breathing and vigorous breathing (which here means nasal snorting, voluntary coughing and voluntary sneezing). Unsupported (natural) breathing and NHF at 30 and 60 LPM were compared. RESULTS: Imaging: During quiet breathing, no particles were recorded with unsupported breathing or 30 LPM NHF (detection limit for single particles 33 µm). Particles were detected from 2 of 6 participants at 60 LPM quiet breathing at approximately 10% of the rate caused by unsupported vigorous breathing. Unsupported vigorous breathing released the greatest numbers of particles. Vigorous breathing with NHF at 60 LPM, released half the number of particles compared to vigorous breathing without NHF.Chemical marker tests: No oral/nasal fluid was detected in quiet breathing without NHF (detection limit 0.28 µL/m3). In quiet breathing with NHF at 60 LPM, small quantities were detected in 4 out of 29 quiet breathing tests, not exceeding 17 µL/m3. Vigorous breathing released 200-1000 times more fluid than the quiet breathing with NHF. The quantities detected in vigorous breathing were similar whether using NHF or not. CONCLUSION: During quiet breathing, 60 LPM NHF therapy may cause oral/nasal fluid to be released as particles, at levels of tens of µL per cubic metre of air. Vigorous breathing (snort, cough or sneeze) releases 200 to 1000 times more oral/nasal fluid than quiet breathing (p < 0.001 with both imaging and chemical marker methods). During vigorous breathing, 60 LPM NHF therapy caused no statistically significant difference in the quantity of oral/nasal fluid released compared to unsupported breathing. NHF use does not increase the risk of dispersing infectious aerosols above the risk of unsupported vigorous breathing. Standard infection prevention and control measures should apply when dealing with a patient who has an acute respiratory infection, independent of which, if any, respiratory support is being used. CLINICAL TRIAL REGISTRATION: ACTRN12614000924651.

A physiological study to determine the mechanism of carbon dioxide clearance during apnoea when using transnasal humidified rapid insufflation ventilatory exchange (THRIVE).

Clinical observations suggest that compared with standard apnoeic oxygenation, transnasal humidified rapid-insufflation ventilatory exchange using high-flow nasal oxygenation reduces the rate of carbon dioxide accumulation in patients who are anaesthetised and apnoeic. This suggests that active gas exchange takes place, but the mechanisms by which it may occur have not been described. We used three laboratory airway models to investigate mechanisms of carbon dioxide clearance in apnoeic patients. We determined flow patterns using particle image velocimetry in a two-dimensional model using particle-seeded fluorescent solution; visualised gas clearance in a three-dimensional printed trachea model in air; and measured intra-tracheal turbulence levels and carbon dioxide clearance rates using a three-dimensional printed model in air mounted on a lung simulator. Cardiogenic oscillations were simulated in all experiments. The visualisation experiments indicated that gaseous mixing was occurring in the trachea. With no cardiogenic oscillations applied, mean (SD) carbon dioxide clearance increased from 0.29 (0.04) ml.min-1 to 1.34 (0.14) ml.min-1 as the transnasal humidified rapid-insufflation ventilatory exchange flow rate was increased from 20 l.min-1 to 70 l.min-1 (p = 0.0001). With a cardiogenic oscillation of 20 ml.beat-1 applied, carbon dioxide clearance increased from 11.9 (0.50) ml.min-1 to 17.4 (1.2) ml.min-1 as the transnasal humidified rapid-insufflation ventilatory exchange flow rate was increased from 20 l.min-1 to 70 l.min-1 (p = 0.0014). These findings suggest that enhanced carbon dioxide clearance observed under apnoeic conditions with transnasal humidified rapid-insufflation ventilatory exchange, as compared with classical apnoeic oxygenation, may be explained by an interaction between entrained and highly turbulent supraglottic flow vortices created by high-flow nasal oxygen and cardiogenic oscillations.

Differences between endogenous attention to spatial locations and sensory modalities.

Vibell et al. (J Cogn Neurosci 19:109-120, 2007) reported that endogenously attending to a sensory modality (vision or touch) modulated perceptual processing, in part, by the relative speeding-up of neural activation (i.e., as a result of prior entry). However, it was unclear whether it was the fine temporal discrimination required by the temporal-order judgment task that was used, or rather, the type of attentional modulation (spatial locations or sensory modalities) that was responsible for the shift in latencies that they observed. The present study used a similar experimental design to evaluate whether spatial attention would also yield similar latency effects suggestive of prior entry in the early visual P1 potentials. Intriguingly, while the results demonstrate similar neural latency shifts attributable to spatial attention, they started at a somewhat later stage than seen in Vibell et al.'s study. These differences are consistent with different neural mechanisms underlying attention to a specific sensory modality versus to a spatial location.

The Development of Tactile Perception.

Touch is the first of our senses to develop, providing us with the sensory scaffold on which we come to perceive our own bodies and our sense of self. Touch also provides us with direct access to the external world of physical objects, via haptic exploration. Furthermore, a recent area of interest in tactile research across studies of developing children and adults is its social function, mediating interpersonal bonding. Although there are a range of demonstrations of early competence with touch, particularly in the domain of haptics, the review presented here indicates that many of the tactile perceptual skills that we take for granted as adults (e.g., perceiving touches in the external world as well as on the body) take some time to develop in the first months of postnatal life, likely as a result of an extended process of connection with other sense modalities which provide new kinds of information from birth (e.g., vision and audition). Here, we argue that because touch is of such fundamental importance across a wide range of social and cognitive domains, it should be placed much more centrally in the study of early perceptual development than it currently is.

Carbon dioxide insufflation deflects airborne particles from an open surgical wound model.

BACKGROUND: Surgical site infections remain a significant burden on healthcare systems and may benefit from new countermeasures. AIM: To assess the merits of open surgical wound CO2 insufflation via a gas diffuser to reduce airborne contamination, and to determine the distribution of CO2 in and over a wound. METHODS: An experimental approach with engineers and clinical researchers was employed to measure the gas flow pattern and motion of airborne particles in a model of an open surgical wound in a simulated theatre setting. Laser-illuminated flow visualizations were performed and the degree of protection was quantified by collecting and characterizing particles deposited in and outside the wound cavity. FINDINGS: The average number of particles entering the wound with a diameter of <5µm was reduced 1000-fold with 10L/min CO2 insufflation. Larger and heavier particles had a greater penetration potential and were reduced by a factor of 20. The degree of protection was found to be unaffected by exaggerated movements of hands in and out of the wound cavity. The steady-state CO2 concentration within the majority of the wound cavity was >95% and diminished rapidly above the wound to an atmospheric level (∼0%) at a height of 25mm. CONCLUSION: Airborne particles were deflected from entering the wound by the CO2 in the cavity akin to a protective barrier. Insufflation of CO2 may be an effective means of reducing intraoperative infection rates in open surgeries.

Visually Induced Inhibition of Return Affects the Integration of Auditory and Visual Information.

Multisensory integration (MSI) and exogenous spatial attention can both speedup responses to perceptual events. Recently, it has been shown that audiovisual integration at exogenously attended locations is reduced relative to unattended locations. This effect was observed at short cue-target intervals (200-250 ms). At longer intervals, however, the initial benefits of exogenous shifts of spatial attention at the cued location are often replaced by response time (RT) costs (also known as Inhibition of Return, IOR). Given these opposing cueing effects at shorter versus longer intervals, we decided to investigate whether MSI would also be affected by IOR. Uninformative exogenous visual spatial cues were presented between 350 and 450 ms prior to the onset of auditory, visual, and audiovisual targets. As expected, IOR was observed for visual targets (invalid cue RT < valid cue RT). For auditory and audiovisual targets, neither IOR nor any spatial cueing effects were observed. The amount of relative multisensory response enhancement and race model inequality violation was larger for uncued as compared with cued locations indicating that IOR reduces MSI. The results are discussed in the context of changes in unisensory signal strength at cued as compared with uncued locations.

The Complex Interplay Between Multisensory Integration and Perceptual Awareness.

The integration of information has been considered a hallmark of human consciousness, as it requires information being globally available via widespread neural interactions. Yet the complex interdependencies between multisensory integration and perceptual awareness, or consciousness, remain to be defined. While perceptual awareness has traditionally been studied in a single sense, in recent years we have witnessed a surge of interest in the role of multisensory integration in perceptual awareness. Based on a recent IMRF symposium on multisensory awareness, this review discusses three key questions from conceptual, methodological and experimental perspectives: (1) What do we study when we study multisensory awareness? (2) What is the relationship between multisensory integration and perceptual awareness? (3) Which experimental approaches are most promising to characterize multisensory awareness? We hope that this review paper will provoke lively discussions, novel experiments, and conceptual considerations to advance our understanding of the multifaceted interplay between multisensory integration and consciousness.

An Experimental and Numerical Investigation of CO2 Distribution in the Upper Airways During Nasal High Flow Therapy.

Nasal high flow (NHF) therapy is used to treat a variety of respiratory disorders to improve patient oxygenation. A CO2 washout mechanism is believed to be responsible for the observed increase in oxygenation. In this study, experimentally validated Computational Fluid Dynamics simulations of the CO2 concentration within the upper airway during unassisted and NHF assisted breathing were undertaken with the aim of exploring the existence of this washout mechanism. An anatomically accurate nasal cavity model was generated from a CT scan and breathing was reproduced using a Fourier decomposition of a physiologically measured breath waveform. Time dependent CO2 profiles were obtained at the entrance of the trachea in the experimental model, and were used as simulation boundary conditions. Flow recirculation features were observed in the anterior portion of the nasal cavity upon application of the therapy. This causes the CO2 rich gas to vent from the nostrils reducing the CO2 concentration in the dead space and lowering the inspired CO2 volume. Increasing therapy flow rate increases the penetration depth within the nasal cavity of the low CO2 concentration gas. A 65% decrease in inspired CO2 was observed for therapy flow rates ranging from 0 to 60 L min(-1) supporting the washout mechanism theory.

Modulation of pain via expectation of its location.

BACKGROUND: The spatial precision of expectancy effects on pain is unclear. We hypothesized that expecting nociceptive stimuli at particular skin sites would have an analgesic effect on nociceptive stimuli presented between them (middle zone). METHODS: Laser stimuli (evoking pin-prick pain) were delivered to three discrete skin zones on the forearm, under two conditions. During 'Localization', participants' expectation of stimuli was spatially divided between two locations (expected stimuli in only the outer two skin zones): pain intensity and stimulus location were judged. During 'No-localization' (control condition), participants had no expectation concerning stimulus location; only pain intensity was rated. Additional experiments assessed the importance of the actual location on the forearm by: shifting all skin zones proximally towards the elbow (control for joint proximity, Experiment 2); adding a fourth zone distally (control for interaction between joint proximity and enhanced distal inhibition, Experiment 3). RESULTS: All experiments demonstrated spatially specific pain modulation, but only Experiment 2 (near elbow) supported our hypothesis: middle zone pain intensity was significantly lower (p = 0.02) during Localization than No-localization. Experiment 1 (near wrist) found reduced pain intensity during Localization only for the distal zone (p = 0.04). Experiment 3 confirmed this effect: reduced pain during Localization occurred only for the most distal zone (p = 0.046). CONCLUSION: Expecting a painful stimulus in non-adjacent skin sites has spatially specific effects on pain modulation, but this reflects an interaction between the expected location of stimulation and the actual location. This suggests a more complex connection between somatotopic maps and nociceptive modulation than previously thought; several distinct mechanisms likely contribute.

Experimental and computational investigation of the trajectories of blood drops ejected from the nose.

Blood expirated from the nose may leave a characteristic bloodstain at a crime scene which can provide important clues for reconstructing events during a violent assault. Little research has been done on the typical velocities, trajectories and size distribution that can be expected from expirated blood. An experimental fluid dynamics technique known as stereoscopic particle image velocimetry is used in this work to obtain the air velocity field inside and outside the nostrils during exhalation. A numerical model was then used to compute the trajectory of blood drops of 0.5 and 2 mm. The drops were tracked until ground plane impact below the nostril exit. Three heights were investigated, 1.5, 1.6 and 1.7 m. For an expiration flow rate of 32 l/min in vivo, there is a maximum exit velocity from the nostril of approximately 4 m/s, with a 0.5 m/s difference between nostrils. After the drops have traversed the distances investigated, drops of 0.5 and 2 mm in diameter from both nostrils are at a similar velocity. This implies that the gravitational acceleration after the drops leave the jet has the most influence on velocity. It is however shown that exit velocity does affect impact location. Drop size affects both impact location and impact velocity. An increase in height increases the distance traversed. Compared to the 2-mm drop, the 0.5 mm had a lower impact velocity, but its impact location in the ground plane was further from the nostril exit. Understanding the physics of expirated blood flight allows better interpretation of expirated stains at crime scenes.

On the relative contributions of multisensory integration and crossmodal exogenous spatial attention to multisensory response enhancement.

Two processes that can give rise to multisensory response enhancement (MRE) are multisensory integration (MSI) and crossmodal exogenous spatial attention. It is, however, currently unclear what the relative contribution of each of these is to MRE. We investigated this issue using two tasks that are generally assumed to measure MSI (a redundant target effect task) and crossmodal exogenous spatial attention (a spatial cueing task). One block of trials consisted of unimodal auditory and visual targets designed to provide a unimodal baseline. In two other blocks of trials, the participants were presented with spatially and temporally aligned and misaligned audiovisual (AV) targets (0, 50, 100, and 200ms SOA). In the integration block, the participants were instructed to respond to the onset of the first target stimulus that they detected (A or V). The instruction for the cueing block was to respond only to the onset of the visual targets. The targets could appear at one of three locations: left, center, and right. The participants were instructed to respond only to lateral targets. The results indicated that MRE was caused by MSI at 0ms SOA. At 50ms SOA, both crossmodal exogenous spatial attention and MSI contributed to the observed MRE, whereas the MRE observed at the 100 and 200ms SOAs was attributable to crossmodal exogenous spatial attention, alerting, and temporal preparation. These results therefore suggest that there may be a temporal window in which both MSI and exogenous crossmodal spatial attention can contribute to multisensory response enhancement.

Hypervigilance for innocuous tactile stimuli in patients with fibromyalgia: an experimental approach.

BACKGROUND: Hypervigilance, i.e., excessive attention, is often invoked as a potential explanation for the observation that many individuals with fibromyalgia show a heightened sensitivity to stimulation in various sensory modalities, such as touch and hearing. Compelling evidence for this assumption is, however, lacking. The aim of the present study was to investigate the presence of somatosensory hypervigilance in patients with fibromyalgia. METHODS: Fibromyalgia patients (n = 41) and a matched control group (n = 40) performed a tactile change detection task in which they had to detect whether there was a change between two consecutively presented patterns of tactile stimuli presented to various body locations. The task was performed under two conditions: in the unpredictable condition, tactile changes occurred equally often at all possible body locations; in the predictable condition, the majority of tactile changes occurred at one specific body location. RESULTS: It was hypothesized that the fibromyalgia group would show better tactile change detection in the unpredictable condition and when changes ocurred at unexpected locations in the predictable condition. The results did not support this hypothesis. In neither condition was the fibromyalgia group better than the control group in detecting tactile changes. CONCLUSIONS: No evidence was found to support the claim that patients with fibromyalgia display somatosensory hypervigilance. This finding challenges the idea of hypervigilance as a static feature of fibromyalgia and urges for a more dynamic view in which hypervigilance emerges in situations when bodily threat is experienced.

Multisensory interactions in the depth plane in front and rear space: a review.

In this review, we evaluate the neurophysiological, neuropsychological, and psychophysical evidence relevant to the claim that multisensory information is processed differently depending on the region of space in which it happens to be presented. We discuss how the majority of studies of multisensory interactions in the depth plane that have been conducted to date have focused on visuotactile and audiotactile interactions in frontal peripersonal space and underline the importance of such multisensory interactions in defining peripersonal space. Based on our review of studies of multisensory interactions in depth, we question the extent to which peri- and extra-personal space (both frontal and rear) are characterized by differences in multisensory interactions (as evidenced by multisensory stimuli producing a different behavioral outcome as compared to unisensory stimulation). In addition to providing an overview of studies of multisensory interactions in different regions of space, our goal in writing this review has been to demonstrate that the various kinds of multisensory interactions that have been documented may follow very similar organizing principles. Multisensory interactions in depth that involve tactile stimuli are constrained by the fact that such stimuli typically need to contact the skin surface. Therefore, depth-related preferences of multisensory interactions involving touch can largely be explained in terms of their spatial alignment in depth and their alignment with the body. As yet, no such depth-related asymmetry has been observed in the case of audiovisual interactions. We therefore suggest that the spatial boundary of peripersonal space and the enhanced audiotactile and visuotactile interactions that occur in peripersonal space can be explained in terms of the particular spatial alignment of stimuli from different modalities with the body and that they likely reflect the result of prior multisensory experience.

Fibromyalgia patients and controls are equally accurate in detecting tactile stimuli while observing another in pain: an experimental study.

This study investigated the effects of observing pain in others upon vicarious somatosensory experiences and the detection of somatosensory stimuli in both fibromyalgia (FM) patients and controls. The putative modulatory role of dispositional empathy, hypervigilance to pain, and central sensitization was examined. FM patients (n = 39) and controls (n = 38) saw videos depicting pain-related (hands being pricked) and non-pain-related scenes, while occasionally experiencing vibrotactile stimuli themselves on the left, right, or both hands. Participants reported the location at which they felt a somatosensory stimulus. Tactile and visual scenes were presented in the same spatial location (congruent; e.g., left-left) or from opposite locations (incongruent; e.g., left-right). We calculated the proportion of correct responses, vicarious somatosensory experiences (i.e., trials on which an illusory somatosensory experience was reported while observing pain-related scenes), and neglect errors (i.e., reporting only the site congruent to the visual pain-related information when both hands had been stimulated). Observing another in pain resulted in an equal numbers of vicarious somatosensory experiences in both groups and facilitated the detection of tactile stimuli, especially during spatially congruent trials. Counter to our expectations, this facilitation was not moderated by group. FM patients made fewer neglect errors. Hypervigilance for pain, dispositional empathy, and central sensitization did not exert a modulatory role. Observing pain facilitates the detection of tactile stimuli in FM patients and controls. Overall, a low incidence of vicarious experiences was observed. Further research is needed to understand the role of attentional body focus in the elicitation of vicarious experiences.

Microbial production of volatile sulphur compounds in the large intestine of pigs fed two different diets.

AIMS: To investigate the production of volatile sulphur compounds (VSC) in the segments of the large intestine of pigs and to assess the impact of diet on this production. METHODS AND RESULTS: Pigs were fed two diets based on either wheat and barley (STD) or wheat and dried distillers grains with solubles (DDGS). Net production of VSC and potential sulphate reduction rate (SRR) (sulphate saturated) along the large intestine were determined by means of in vitro incubations. The net production rate of hydrogen sulphide and potential SRR increased from caecum towards distal colon and were significantly higher in the STD group. Conversely, the net methanethiol production rate was significantly higher in the DDGS group, while no difference was observed for dimethyl sulphide. The number of sulphate-reducing bacteria and total bacteria were determined by quantitative PCR and showed a significant increase along the large intestine, whereas no diet-related differences were observed. CONCLUSION: VSC net production varies widely throughout the large intestine of pigs and the microbial processes involved in this production can be affected by diet. SIGNIFICANCE AND IMPACT OF THE STUDY: This first report on intestinal production of all VSC shows both spatial and dietary effects, which are relevant to both bowel disease- and odour mitigation research.

Effect of dietary inorganic sulfur level on growth performance, fecal composition, and measures of inflammation and sulfate-reducing bacteria in the intestine of growing pigs.

Two experiments investigated the impact of dietary inorganic S on growth performance, intestinal inflammation, fecal composition, and the presence of sulfate-reducing bacteria (SRB). In Exp. 1, individually housed pigs (n = 42; 13.8 kg) were fed diets containing 2,300 or 2,100 mg/kg of S for 24 d. Decreasing dietary S had no effect on ADG, ADFI, or G:F. In Exp. 2, pigs (n = 64; 13.3 kg) were fed diets containing 0, 0.625, 1.25, 2.5, or 5.0% CaSO(4), thereby increasing dietary S from 2,900 to 12,100 mg/kg. Two additional diets were fed to confirm the lack of an impact due to feeding low dietary S on pig performance and to determine if the increased Ca and P content in the diets containing CaSO(4) had an impact on growth performance. Pigs were fed for 35 d. Ileal tissue, ileal mucosa, and colon tissue were harvested from pigs fed the 0 and 5% CaSO(4) diets (low-S and high-S, respectively) to determine the impact of dietary S on inflammation-related mRNA, activity of mucosal alkaline phosphatase and sucrase, and pathways of inflammatory activation. Real-time PCR was used to quantify SRB in ileal and colon digesta samples and feces. Fecal pH, sulfide, and ammonia concentrations were also determined. There was no impact on growth performance in pigs fed the diet reduced in dietary S or by the increase of dietary Ca and P. Increasing dietary S from 2,900 to 12,100 mg/kg had a linear (P < 0.01) effect on ADG and a cubic effect (P < 0.05) on ADFI and G:F. Real-time reverse-transcription PCR analysis revealed that pigs fed high-S increased (P < 0.05) the relative abundance of intracellular adhesion molecule-1, tumor necrosis factor-α, and suppressor of cytokine signaling-3 mRNA, and tended (P = 0.09) to increase the relative abundance of IL-6 mRNA in ileal tissue. Likewise, pigs fed high-S had reduced (P < 0.05) abundance of nuclear factor of κ light polypeptide gene enhancer in B-cells inhibitor-α and increased (P < 0.05) phospho-p44/p42 mitogen-activated protein kinase in ileal tissue, but there was no effect of dietary S on mucosal alkaline phosphatase or sucrase activity. Pigs fed the high-S diet had decreased (P < 0.05) total bacteria in ileal digesta, but increased (P < 0.05) prevalence of SRB in colon contents. Fecal sulfide was increased (P < 0.05) and fecal pH was deceased (P < 0.05) in pigs fed high-S. The data indicate that growing pigs can tolerate relatively high amounts of dietary inorganic S, but high dietary S content alters inflammatory mediators and intestinal bacteria.

Racial disparity in hospice use in the United States in 2002.

We used complete Centers for Disease Control death certificate records and the Centers for Medicare and Medicaid Services 100% Standard Analytic File for hospice claims for 2002 to examine differences in hospice utilization between African-American and white decedents living in the United States. White decedents were more likely to use hospice in the year before their death than African-American decedents (29% vs 22%). Cause-specific hospice utilization rates among women were consistently higher than among men within a given race. African-American decedents were consistently less likely to use hospice than white decedents for almost all conditions. Hospice utilization was lower among African-American than among white decedents in 31 of 40 states. The higher the overall hospice utilization in a state, the less the positive difference between white and African-American usage rates; that is, the more accepted hospice is, as measured by 'market share', the lower the racial disparity in its use.