Many-body theory calculations of positronic-bonded molecular dianions.

The energetic stability of positron-dianion systems [A-; e+; A-] is studied via many-body theory, where A- includes H-, F-, Cl-, and the molecular anions (CN)- and (NCO)-. Specifically, the energy of the system as a function of ionic separation is determined by solving the Dyson equation for the positron in the field of the two anions using a positron-anion self-energy as constructed in Hofierka et al. [Nature 606, 688 (2022)] that accounts for correlations, including polarization, screening, and virtual-positronium formation. Calculations are performed for a positron interacting with H22-, F22-, and Cl22- and are found to be in good agreement with previous theory. In particular, we confirm the presence of two minima in the potential energy of the [H-; e+; H-] system with respect to ionic separation: a positronically bonded [H-; e+; H-] local minimum at ionic separations r ∼ 3.4 Å and a global minimum at smaller ionic separations r ≲ 1.6 Å that gives overall instability of the system with respect to dissociation into a H2 molecule and a positronium negative ion, Ps-. The first predictions are made for positronic bonding in dianions consisting of molecular anionic fragments, specifically for (CN)22- and (NCO)22-. In all cases, we find that the molecules formed by the creation of a positronic bond are stable relative to dissociation into A- and e+A- (positron bound to a single anion), with bond energies on the order of 1 eV and bond lengths on the order of several ångstroms.

Maxwellianization of Positrons Cooling in CF_{4} and N_{2} Gases.

Positron cooling in CF_{4} and N_{2} gases via inelastic vibrational and rotational (de)excitations is simulated, importantly including elastic positron-positron collisions. For CF_{4}, it is shown that rotational (de)excitations play no role on the experimental timescale, and further, that in the absence of positron-positron collisions, cooling via excitation of the dipole-active ν_{3} and ν_{4} modes alone would lead to a non-Maxwellian positron momentum distribution, in contrast to the observations of experiment. It is shown that the observed Maxwellianization of the distribution may be effected by positron-positron collisions and/or cooling involving the combination of the dipole-inactive ν_{1} mode with the dipole-active modes. For N_{2}, rotational excitations alone are sufficient to Maxwellianize the distribution (vibrational effects are negligible).

Many-Body Theory Calculations of Positron Scattering and Annihilation in H_{2}, N_{2}, and CH_{4}.

The recently developed ab initio many-body theory of positron molecule binding [22J. Hofierka et al., Many-body theory of positron binding to polyatomic molecules, Nature (London) 606, 688 (2022)NATUAS0028-083610.1038/s41586-022-04703-3] is combined with the shifted pseudostates method [A. R. Swann and G. F. Gribakin, Model-potential calculations of positron binding, scattering, and annihilation for atoms and small molecules using a Gaussian basis, Phys. Rev. A 101, 022702 (2020)PLRAAN2469-992610.1103/PhysRevA.101.022702] to calculate positron scattering and annihilation rates on small molecules, namely H_{2}, N_{2}, and CH_{4}. The important effects of positron-molecule correlations are delineated. The method provides uniformly good results for annihilation rates on all the targets, from the simplest (H_{2}, for which only a sole previous calculation agrees with experiment), to larger targets, where high-quality calculations have not been available.

Exploring views of members of the public and policymakers on the acceptability of population level dietary and active-travel policies: a qualitative study.

BACKGROUND: There is limited evidence on what shapes the acceptability of population level dietary and active-travel policies in England. This information would be useful in the decision-making process about which policies should be implemented and how to increase their effectiveness and sustainability. To fill this gap, we explored public and policymakers' views about factors that influence public acceptability of dietary and active-travel policies and how to increase public acceptability for these policies. METHODS: We conducted online, semi-structured interviews with 20 members of the public and 20 policymakers in England. A purposive sampling frame was used to recruit members of the public via a recruitment agency, based on age, sex, socioeconomic status and ethnicity. Policymakers were recruited from existing contacts within our research collaborations and via snowball sampling. We explored different dietary and active-travel policies that varied in their scope and focus. Interviews were transcribed verbatim and analysed using thematic reflexive analysis with both inductive and deductive coding. RESULTS: We identified four themes that informed public acceptability of dietary and active-travel policies: (1) perceived policy effectiveness, i.e., policies that included believable mechanisms of action, addressed valued co-benefits and barriers to engage in the behaviour; (2) perceived policy fairness, i.e., policies that provided everyone with an opportunity to benefit (mentioned only by the public), equally considered the needs of various population subgroups and rewarded 'healthy' behaviours rather than only penalising 'unhealthy' behaviours; (3) communication of policies, i.e., policies that were visible and had consistent and positive messages from the media (mentioned only by policymakers) and (4) how to improve policy support, with the main suggestion being an integrated strategy addressing multiple aspects of these behaviours, inclusive policies that consider everyone's needs and use of appropriate channels and messages in policy communication. CONCLUSIONS: Our findings highlight that members' of the public and policymakers' support for dietary and active-travel policies can be shaped by the perceived effectiveness, fairness and communication of policies and provide suggestions on how to improve policy support. This information can inform the design of acceptable policies but can also be used to help communicate existing and future policies to maximise their adoption and sustainability.

Rates and Reasons for Readmission after Hospitalisation on the Acute Medical Unit.

INTRODUCTION: Readmission after hospital discharge is an ongoing challenge that healthcare systems face worldwide, with multimorbidity increasing the readmission risk significantly. Identifying higher risk groups of patients allows for safety netting at discharge to be implemented to prevent harm. The aim of this study was to compare readmission rates and reasons across common diagnostic groups presenting to the acute medical unit. METHOD: A retrospective analysis was performed on an anonymous dataset extracted from Salford Royal Hospital from 2014 - 2022 covering all non-elective inpatient admissions to AMU or medical same day emergency care where the patient survived to discharge. Episodes were grouped according to ICD-10 diagnostic codes, with readmission rates and reasons at 30 and 90 day calculated and compared using descriptive statistics. Further subgroups were evaluated according to demographic and co-morbid features. RESULTS: There were 89,897 admissions to AMU and SDEC where patients survived to discharge: age 68±19 years, 53% female. 5,880 episodes were excluded due to inpatient death. The most common first admission reasons were pneumonia (n=9,121), COPD (4,800) and sepsis (3,440). The overall 30 day readmission rate was 12.3%, with the highest rates being found where first admission episode was due to liver disease (21.9%), chronic obstructive pulmonary disease (COPD, 21.1%), and falls (17.9%). 6% of all patients were readmitted within 30 days due to recurrence of the primary presenting illness, representing 49% of all readmissions. After primary illness recurrence, pneumonia was the second most common readmission reason in 17 of 22 diagnostic groups and accounted for 25% of all readmissions excluding primary illness recurrence. Overall 90 day readmission rate was 24.2% with the same 3 most common diagnostic groups (liver disease 44%, COPD 39% and falls 34%). For 90 day readmission reasons according to specified comorbidities, the highest rates were seen in heart failures (34.1%) and COPD (33.1%). The highest readmission reason in the diagnostic groups was 41.4% of heart failure patients being readmitted with respiratory causes. Heart failure was the most impactful co-morbid factor associated with higher likelihood of 90 day readmission in other disease presentations (34.4% with heart failure, 22.8% without). DISCUSSION: Readmission rates vary significantly between diagnostic and co-morbid groups meaning that targeting high risk groups for safety netting may be possible using only simple admission details.

Emergency admissions' diagnoses and risk of in-hospital death according to the primary ICD-10 chapter assigned at discharge and the National Early Warning Score on admission.

BACKGROUND: The relationship between diagnosis, illness severity, and mortality risk for unselected emergency admissions is poorly defined. AIM: To define primary ICD-10 diagnostic chapters at discharge, admission illness severity by the National Early Warning Score, and in-hospital mortality for all unselected emergency admissions. METHOD: Retrospective, observational, cohort study of 122,259 unselected, adult emergency admissions to Salford Royal Hospital between 2014 and 2022. RESULTS: In-hospital mortality was 4.3% but most patients had an ICD-10 chapter associated with a lower risk of death. 60% of in-hospital deaths were in four chapters, infections, circulatory and respiratory diseases, or neoplasms. An admission NEWS ≥3 was associated with earlier mortality and an eight-fold increased risk of in-hospital mortality. 45% of all in-hospital deaths occurred in patients with an admission NEWS <3. CONCLUSION: Mortality in emergency hospital admissions is associated with illness severity and four diagnostic chapters. NEWS should not be the only arbiter of hospital admission, as for certain diagnostic chapters the risk of death is high even if vital signs on presentation are normal.

Identification of tissue-dependent proteins in knee OA synovial fluid.

OBJECTIVE: For many proteins from osteoarthritic synovial fluid, their intra-articular tissue of origin remains unknown. In this study we performed comparative proteomics to identify osteoarthritis-specific and joint tissue-dependent secreted proteins that may serve as candidates for osteoarthritis biomarker development on a tissue-specific basis. DESIGN: Protein secretomes of cartilage, synovium, Hoffa's fat pad and meniscus from knee osteoarthritis patients were determined using liquid chromatography tandem mass spectrometry, followed by label-free quantification. Validation of tissue-dependent protein species was conducted by ELISA on independent samples. Differential proteomes of osteoarthritic and non-osteoarthritic knee synovial fluids were obtained via similar proteomics approach, followed by ELISA validation. RESULTS: Proteomics revealed 64 proteins highly secreted from cartilage, 94 from synovium, 37 from Hoffa's fat pad and 21 from meniscus. Proteomic analyses of osteoarthritic vs non-osteoarthritic knee synovial fluid revealed 70 proteins with a relatively higher abundance and 264 proteins with a relatively lower abundance in osteoarthritic synovial fluid. Of the 70 higher abundance proteins, 23 were amongst the most highly expressed in the secretomes of a specific intra-articular tissue measured. Tissue-dependent release was validated for SLPI, C8, CLU, FN1, RARRES2, MATN3, MMP3 and TNC. Abundance in synovial fluid of tissue-dependent proteins was validated for IGF2, AHSG, FN1, CFB, KNG and C8. CONCLUSIONS: We identified proteins with a tissue-dependent release from intra-articular human knee OA tissues. A number of these proteins also had an osteoarthritis-specific abundance in knee synovial fluid. These proteins may serve as novel candidates for osteoarthritis biomarker development on a tissue-specific basis.

Process and Outcome Evaluation of a Mindfulness-Based Cognitive Therapy Intervention for Cisgender and Transgender African American Women Living with HIV/AIDS.

There is a need for evidence-based contextualized mental health interventions for persons living with HIV/AIDS. In the current study, the primary researcher conducted open trials with African American women living with HIV/AIDS (AAWLWHA) to examine the acceptability and feasibility of Project UPLIFT, a mindfulness-based cognitive therapy intervention that has demonstrated effectiveness in persons living with epilepsy. Women were recruited for a tele-delivered phone intervention group separated by gender identity, as well as participated in pre- and post-test assessments. Additionally, data on acceptability was collected. Both cis- and transgender women were highly satisfied with the intervention and demonstrated improvement in depressive and stress symptoms. The intervention seemed to be particularly feasible for cisgender women, though more qualitative mental health research may be warranted with transgender women. The current research has implications for the utility of mindfulness-based interventions such as UPLIFT, with AAWLWHA.

The upper limb of Paranthropus boisei from Ileret, Kenya.

Paranthropus boisei was first described in 1959 based on fossils from the Olduvai Gorge and now includes many fossils from Ethiopia to Malawi. Knowledge about its postcranial anatomy has remained elusive because, until recently, no postcranial remains could be reliably attributed to this taxon. Here, we report the first associated hand and upper limb skeleton (KNM-ER 47000) of P. boisei from 1.51 to 1.53 Ma sediments at Ileret, Kenya. While the fossils show a combination of primitive and derived traits, the overall anatomy is characterized by primitive traits that resemble those found in Australopithecus, including an oblique scapular spine, relatively long and curved ulna, lack of third metacarpal styloid process, gracile thumb metacarpal, and curved manual phalanges. Very thick cortical bone throughout the upper limb shows that P. boisei had great upper limb strength, supporting hypotheses that this species spent time climbing trees, although probably to a lesser extent than earlier australopiths. Hand anatomy shows that P. boisei, like earlier australopiths, was capable of the manual dexterity needed to create and use stone tools, but lacked the robust thumb of Homo erectus, which arguably reflects adaptations to the intensification of precision grips and tool use. KNM-ER 47000 provides conclusive evidence that early Pleistocene hominins diverged in postcranial and craniodental anatomy, supporting hypotheses of competitive displacement among these contemporaneous hominins.

Palliative care advanced practice nursing in Israel: bridging creation and implementation.

AIM: To describe Israel's development of the palliative care advanced practice registered nurse as a foundation for the development of the advanced practice registered nurse role in other specialties. BACKGROUND: Palliative care centres on alleviating physical, emotional, social and spiritual distress associated with life-limiting illness. In 2009, Israel introduced the palliative care advanced practice nurse role, that is, registered nurses with specialized training in palliative care, to address increasing palliative care needs. INTRODUCTION: While there has been investment in its development, full implementation of the advanced practice nurse has not yet been achieved. METHODS: In this qualitative descriptive study, we conducted a document analysis (n = 11) and key informant interviews (n = 11), extracted themes using qualitative content analysis and triangulated data sets. RESULTS: Documents reflected growing palliative care needs and uniform requirements for advanced practice nurse training. Interviews uncovered a perceived lack of awareness of palliative care, the need for increased role definition and practice authority for advanced practice nurses, and barriers to entry and training for this role. DISCUSSION: Findings highlight ongoing needs in palliative care and advanced practice nursing and a trajectory of growth. CONCLUSIONS: The challenges Israel faces in implementation of the palliative care advanced practice nurse role inform development of other advanced practice nursing roles in Israel and other countries. IMPLICATIONS FOR NURSING PRACTICE: Streamlining training pathways and resolving scope of practice issues will assist in implementation of advanced practice nursing roles. IMPLICATIONS FOR HEALTH POLICY: Our data offer targets for policymakers advocating the advanced practice nurse role, including training requirements and scope of practice.

Arthritis in adults, socioeconomic factors, and the moderating role of childhood maltreatment: cross-sectional data from the National Epidemiological Survey on Alcohol and Related Conditions.

These data present associations between socioeconomic status (SES), different types of childhood maltreatment (CM) history and family dysfunction, and arthritis in men and women across a wide age range. Arthritis was less likely among those with higher SES, regardless of CM history. INTRODUCTION: CM has been associated with increased risk of adult-onset arthritis; however, little is known about whether socioeconomic status moderates arthritis risk in those with CM history. We investigated arthritis across education, income, and race/ethnicity and whether CM moderated associations between SES and arthritis. METHODS: Data were drawn from Wave 2 (2004-2005) of the nationally representative (USA) National Epidemiological Survey on Alcohol and Related Conditions (NESARC, n = 34,563; aged ≥ 20 years). Self-reported CM history included physical abuse, sexual abuse, emotional abuse, emotional neglect, physical neglect, and exposure to intimate partner violence (IPV). We used descriptive statistics and logistic regression to determine relationships between SES, CM, and arthritis. Interaction terms were used to test if CM moderated relationships between SES and arthritis. RESULTS: Arthritis prevalence was 21.1% (n = 3093) among men and 30.1% (n = 6167) among women. In unadjusted analyses, women (p ≤ 0.001) and older age (both sexes, p ≤ 0.01) were associated with increased odds of arthritis. All CM types were associated with increased odds of arthritis, except exposure to IPV among women. In sex-stratified, age-adjusted analyses, lower education and income, family dysfunction, being Hispanic or Asian/Native Hawaiian/Pacific Islander, and ≥ 1 physical comorbidity were associated with increased odds of arthritis among those with and without CM: trends were similar for both sexes. In age-adjusted two-way interaction terms, CM did not moderate associations between SES and arthritis. CONCLUSIONS: Although CM was associated with arthritis, associations between SES and arthritis were not amplified. Arthritis was less likely among those with higher SES, regardless of CM history.

Many-Body Theory for Positronium-Atom Interactions.

A many-body-theory approach has been developed to study positronium-atom interactions. As first applications, we calculate the elastic scattering and momentum-transfer cross sections and the pickoff annihilation rate ^{1}Z_{eff} for Ps collisions with He and Ne. For He the cross section is in agreement with previous coupled-state calculations, while comparison with experiment for both atoms highlights discrepancies between various sets of measured data. In contrast, the calculated ^{1}Z_{eff} (0.13 and 0.26 for He and Ne, respectively) are in excellent agreement with the measured values.

Unresolved Gamma-Ray Sky through its Angular Power Spectrum.

The gamma-ray sky has been observed with unprecedented accuracy in the last decade by the Fermi -large area telescope (LAT), allowing us to resolve and understand the high-energy Universe. The nature of the remaining unresolved emission [unresolved gamma-ray background (UGRB)] below the LAT source detection threshold can be uncovered by characterizing the amplitude and angular scale of the UGRB fluctuation field. This Letter presents a measurement of the UGRB autocorrelation angular power spectrum based on eight years of Fermi-LAT Pass 8 data products. The analysis is designed to be robust against contamination from resolved sources and noise systematics. The sensitivity to subthreshold sources is greatly enhanced with respect to previous measurements. We find evidence (with ∼3.7σ significance) that the scenario in which two classes of sources contribute to the UGRB signal is favored over a single class. A double power law with exponential cutoff can explain the anisotropy energy spectrum well, with photon indices of the two populations being 2.55±0.23 and 1.86±0.15.

Haploinsufficiency of the 22q11.2 microdeletion gene Mrpl40 disrupts short-term synaptic plasticity and working memory through dysregulation of mitochondrial calcium.

Hemizygous deletion of a 1.5- to 3-megabase region on chromosome 22 causes 22q11.2 deletion syndrome (22q11DS), which constitutes one of the strongest genetic risks for schizophrenia. Mouse models of 22q11DS have abnormal short-term synaptic plasticity that contributes to working-memory deficiencies similar to those in schizophrenia. We screened mutant mice carrying hemizygous deletions of 22q11DS genes and identified haploinsufficiency of Mrpl40 (mitochondrial large ribosomal subunit protein 40) as a contributor to abnormal short-term potentiation (STP), a major form of short-term synaptic plasticity. Two-photon imaging of the genetically encoded fluorescent calcium indicator GCaMP6, expressed in presynaptic cytosol or mitochondria, showed that Mrpl40 haploinsufficiency deregulates STP via impaired calcium extrusion from the mitochondrial matrix through the mitochondrial permeability transition pore. This led to abnormally high cytosolic calcium transients in presynaptic terminals and deficient working memory but did not affect long-term spatial memory. Thus, we propose that mitochondrial calcium deregulation is a novel pathogenic mechanism of cognitive deficiencies in schizophrenia.

The Influence of Race and Common Genetic Variations on Outcomes After Pediatric Heart Transplantation.

Significant racial disparity remains in the incidence of unfavorable outcomes following heart transplantation. We sought to determine which pediatric posttransplantation outcomes differ by race and whether these can be explained by recipient demographic, clinical, and genetic attributes. Data were collected for 80 black and 450 nonblack pediatric recipients transplanted at 1 of 6 centers between 1993 and 2008. Genotyping was performed for 20 candidate genes. Average follow-up was 6.25 years. Unadjusted 5-year rates for death (p = 0.001), graft loss (p = 0.015), acute rejection with severe hemodynamic compromise (p = 0.001), late rejection (p = 0.005), and late rejection with hemodynamic compromise (p = 0.004) were significantly higher among blacks compared with nonblacks. Black recipients were more likely to be older at the time of transplantation (p < 0.001), suffer from cardiomyopathy (p = 0.004), and have public insurance (p < 0.001), and were less likely to undergo induction therapy (p = 0.0039). In multivariate regression models adjusting for age, sex, cardiac diagnosis, insurance status, and genetic variations, black race remained a significant risk factor for all the above outcomes. These clinical and genetic variables explained only 8-19% of the excess risk observed for black recipients. We have confirmed racial differences in survival, graft loss, and several rejection outcomes following heart transplantation in children, which could not be fully explained by differences in recipient attributes.

Probing Positron Cooling in Noble Gases via Annihilation γ Spectra.

γ spectra for positron annihilation in noble-gas atoms are calculated using many-body theory for positron momenta up to the positronium-formation threshold. These data are used, together with time-evolving positron-momentum distributions determined in the preceding Letter [Phys. Rev. Lett. 119, 203403 (2017)PRLTAO0031-9007], to calculate the time-varying γ spectra produced during positron cooling in noble gases. The γ spectra and their S[over ¯] and W[over ¯] shape parameters are shown to be sensitive probes of the time evolution of the positron momentum distribution and thus provide a means of studying positron cooling that is complementary to positron lifetime spectroscopy.

Positron Cooling and Annihilation in Noble Gases.

Positron cooling and annihilation in room temperature noble gases is simulated using accurate scattering and annihilation cross sections calculated with many-body theory, enabling the first simultaneous probing of the energy dependence of the scattering and annihilation cross sections. A strikingly small fraction of positrons is shown to survive to thermalization: ∼0.1 in He, ∼0 in Ne, ∼0.15 in Ar, ∼0.05 in Kr, and ∼0.01 in Xe. For Xe, the time-varying annihilation rate Z[over ¯]_{eff}(τ) is shown to be highly sensitive to the depletion of the momentum distribution due to annihilation, conclusively explaining the long-standing discrepancy between gas-cell and trap-based measurements. Overall, the use of the accurate atomic data gives Z[over ¯]_{eff}(τ) in close agreement with experiment for all noble gases except Ne, the experiment for which is proffered to have suffered from incomplete knowledge of the fraction of positrons surviving to thermalization and/or the presence of impurities.

Search for Cosmic-Ray Electron and Positron Anisotropies with Seven Years of Fermi Large Area Telescope Data.

The Large Area Telescope on board the Fermi Gamma-ray Space Telescope has collected the largest ever sample of high-energy cosmic-ray electron and positron events since the beginning of its operation. Potential anisotropies in the arrival directions of cosmic-ray electrons or positrons could be a signature of the presence of nearby sources. We use almost seven years of data with energies above 42 GeV processed with the Pass 8 reconstruction. The present data sample can probe dipole anisotropies down to a level of 10^{-3}. We take into account systematic effects that could mimic true anisotropies at this level. We present a detailed study of the event selection optimization of the cosmic-ray electrons and positrons to be used for anisotropy searches. Since no significant anisotropies have been detected on any angular scale, we present upper limits on the dipole anisotropy. The present constraints are among the strongest to date probing the presence of nearby young and middle-aged sources.

Acute hypoxaemia and vascular function in healthy humans.

NEW FINDINGS: What is the central question of this study? Endothelium-dependent flow-mediated dilatation (FMD) is impaired during acute (60 min) exposure to moderate hypoxia. We examined whether FMD is impaired to the same degree during exposure to milder hypoxia. Additionally, we assessed whether smooth muscle vasodilatory capacity [glyceryl trinitrate (GTN)-induced dilatation] is impaired during acute hypoxic exposure. What is the main finding and its importance? A graded impairment in FMD and GTN-induced dilatation was evident during acute (≤60 min) exposure to mild and moderate hypoxia. This study is the first to document these graded impairments, and provides rationale to examine the relationship between graded increases in sympathetic nerve activity with hypoxia on FMD and GTN-induced dilatation. Endothelium-dependent flow-mediated dilatation (FMD) and endothelium-independent dilatation [induced with glyceryl trinitrate (GTN)] are impaired at high altitude (5050 m), and FMD is impaired after acute exposure (<60 min) to normobaric hypoxia equivalent to ∼5050 m (inspired oxygen fraction âˆ¼0.11). Whether GTN-induced dilatation is impaired acutely and whether FMD is impaired during milder hypoxia are unknown. Therefore, we assessed brachial FMD at baseline and after 30 min of mild (end-tidal PO2 74 ± 2 mmHg) and moderate (end-tidal PO2 50 ± 3 mmHg) normobaric hypoxia (n = 12) or normoxia (time-control trial; n = 10). We also assessed GTN-induced dilatation after the hypoxic FMD tests and in normoxia on a separate control day (n = 8). Compared with the normoxic baseline, reductions during mild and moderate hypoxic exposure were evident in FMD (mild versus moderate, -1.2 ± 1.1 versus -3.1 ± 1.7%; P = 0.01) and GTN-induced dilatation (-2.1 ± 1.0 versus -4.2 ± 2.0%; P = 0.01); the declines in FMD and GTN-induced dilatation were greater during moderate hypoxia (P < 0.01). When allometrically corrected for baseline diameter and FMD shear rate under the curve, FMD was attenuated in both conditions (mild versus moderate, 0.6 ± 0.9 versus 0.8 ± 0.7%; P ≤ 0.01). After 30 min of normoxic time control, FMD was reduced (-0.6 ± 0.3%; P = 0.02). In summary, there was a graded impairment in FMD during mild and moderate hypoxic exposure, which appears to be influenced by shear patterns and incremental decline in smooth muscle vasodilator capacity (impaired GTN-induced dilatation). Our findings from the normoxic control study suggest the decline in FMD in acute hypoxia also appears to be influenced by 30 min of supine rest/inactivity.