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Background: Medical management with anti-impulse therapy and imaging surveillance remains the standard of care for the majority of uncomplicated type B aortic dissections (uTBAD). Failure to adhere to surveillance recommendations may increase the likelihood of aortic degeneration and complications and affect long-term mortality. We sought to analyze adherence to imaging surveillance and identify risk factors for nonadherence in our practice., Methods: In this single-center, retrospective cohort study, demographics, follow-up, and outcomes of patients with acute or subacute uTBAD from August, 20211 to November, 2021 were analyzed. Outcomes were compared between patients with and without routine imaging surveillance. Imaging surveillance was defined as aorta-directed imaging with associated in-person or telephone encounter ≥3 months from index hospitalization. Univariate analysis was used to compare patients with and without imaging surveillance. Multivariate logistic regression was performed to identify factors related to increased odds of adherence to imaging surveillance., Results: A total of 152 medically managed acute or subacute uTBAD patients were identified. Seventy (46.0%) patients underwent imaging surveillance for a median of 16 (interquartile range [IQR] 3.5-29) months. There were no differences in age, sex, race, insurance status, or smoking status between patients with and without surveillance. The median patient home address was 96.1 miles from our center, with no difference between the surveillance (85.7 [IQR 63.5-149.9]) versus no surveillance (106.7 [IQR 70.6-157.6]) groups (P = 0.32). Prior cardiovascular surgery (22.0% vs. 5.7%, P < 0.01) was more common in those without surveillance. Most patients (94.7%) presented as hospital transfers, with no difference between surveillance and non-surveillance groups (P = 0.15). Patients with surveillance were more likely to be discharged home (92.9% vs. 69.5%, P < 0.01). Postdischarge thoracic endovascular aortic repair (TEVAR) occurred in 13.8% of patients and was more common in the surveillance group (25.7% vs. 3.7%, P < 0.01). In TEVAR patients, there was no difference between the rate of urgent or emergent intervention between (P = 1.00) and no difference in the median time to TEVAR (P = 0.15) for surveillance and nonsurveillance groups. Discharge home (OR 5.78, [95% confidence interval [CI] 1.86-17.95, P < 0.01]) was associated with greater odds of imaging surveillance adherence. Previous cardiovascular surgery (OR 0.21, [95% CI 0.06-0.73, P = 0.02]), history of drug use (OR 0.31, [95% CI 0.10-0.97, P = 0.05]), and age (0.96 per unit increase, [95% CI 0.93-0.99, P = 0.02]) were associated with lower odds of imaging surveillance. There was no difference in 5-year survival between groups (log-rank P = 0.26)., Conclusions: Adherence to uTBAD imaging surveillance was low and did not vary by patient demographics or distance from hospital. Patients with imaging surveillance were more likely to undergo TEVAR, although there were no differences in 5-year all-cause survival between groups. Home discharge was associated with the greatest odds of imaging surveillance adherence. This study highlights the difficulty in regional referral center care coordination for treatment of medically managed uTBAD and identifies several factors that may help identify at-risk patients., (Copyright © 2024. Published by Elsevier Inc.)

Advancements in medical imaging and endovascular grafting have facilitated minimally invasive treatments for aortic diseases. Accurate 3D segmentation of the aorta and its branches is crucial for interventions, as inaccurate segmentation can lead to erroneous surgical planning and endograft construction. Previous methods simplified aortic segmentation as a binary image segmentation problem, overlooking the necessity of distinguishing between individual aortic branches. In this paper, we introduce Context-Infused Swin-UNet (CIS-UNet), a deep learning model designed for multi-class segmentation of the aorta and thirteen aortic branches. Combining the strengths of Convolutional Neural Networks (CNNs) and Swin transformers, CIS-UNet adopts a hierarchical encoder-decoder structure comprising a CNN encoder, a symmetric decoder, skip connections, and a novel Context-aware Shifted Window Self-Attention (CSW-SA) module as the bottleneck block. Notably, CSW-SA introduces a unique adaptation of the patch merging layer, distinct from its traditional use in the Swin transformers. CSW-SA efficiently condenses the feature map, providing a global spatial context, and enhances performance when applied at the bottleneck layer, offering superior computational efficiency and segmentation accuracy compared to the Swin transformers. We evaluated our model on computed tomography (CT) scans from 59 patients through a 4-fold cross-validation. CIS-UNet outperformed the state-of-the-art Swin UNetR segmentation model by achieving a superior mean Dice coefficient of 0.732 compared to 0.717 and a mean surface distance of 2.40 mm compared to 2.75 mm. CIS-UNet's superior 3D aortic segmentation offers improved accuracy and optimization for planning endovascular treatments. Our dataset and code will be made publicly available at https://github.com/mirthAI/CIS-UNet., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Machine learning techniques have shown excellent performance in three-dimensional medical image analysis, but have not been applied to acute uncomplicated type B aortic dissection (auTBAD) using Society for Vascular Surgery (SVS) and Society of Thoracic Surgeons (STS)-defined aortic zones. The purpose of this study was to establish a trained, automatic machine learning aortic zone segmentation model to facilitate performance of an aortic zone volumetric comparison between patients with auTBAD based on the rate of aortic growth., Methods: Patients with auTBAD and serial imaging were identified. For each patient, imaging characteristics from two computed tomography (CT) scans were analyzed: (1) the baseline CT angiography (CTA) at the index admission and (2) either the most recent surveillance CTA or the most recent CTA before an aortic intervention. Patients were stratified into two comparative groups based on aortic growth: rapid growth (diameter increase of ≥5 mm/year) and no or slow growth (diameter increase of <5 mm/year). Deidentified images were imported into an open source software package for medical image analysis and images were annotated based on SVS/STS criteria for aortic zones. Our model was trained using four-fold cross-validation. The segmentation output was used to calculate aortic zone volumes from each imaging study., Results: Of 59 patients identified for inclusion, rapid growth was observed in 33 patients (56%) and no or slow growth was observed in 26 patients (44%). There were no differences in baseline demographics, comorbidities, admission mean arterial pressure, number of discharge antihypertensives, or high-risk imaging characteristics between groups (P > .05 for all). Median duration between baseline and interval CT was 1.07 years (interquartile range [IQR], 0.38-2.57). Postdischarge aortic intervention was performed in 13 patients (22%) at a mean of 1.5 ± 1.2 years, with no difference between the groups (P > .05). Among all patients, the largest relative percent increases in zone volumes over time were found in zone 4 (13.9%; IQR, -6.82 to 35.1) and zone 5 (13.4%; IQR, -7.78 to 37.9). There were no differences in baseline zone volumes between groups (P > .05 for all). The average Dice coefficient, a performance measure of the model output, was 0.73. Performance was best in zone 5 (0.84) and zone 9 (0.91)., Conclusions: We describe an automatic deep learning segmentation model incorporating SVS-defined aortic zones. The open source, trained model demonstrates concordance to the manually segmented aortas with the strongest performance in zones 5 and 9, providing a framework for further clinical applications. In our limited sample, there were no differences in baseline aortic zone volumes between patients with rapid growth and patients with no or slow growth., Competing Interests: Disclosures None., (Copyright © 2024 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.)

Background: The association between asymptomatic carotid artery stenosis and impaired cognition, and the cognitive changes after revascularization remain active areas of interest in the field of carotid disease. This narrative review focuses on the association between carotid artery atherosclerosis and impaired cognitive function, proposed mechanisms, and the effects of carotid revascularization on cognition., Methods: A critical review of the literature to identify studies evaluating carotid artery stenosis, cognition, and carotid revascularization was performed using PubMed to query the MEDLINE database through March 2023., Results: Many studies demonstrate a link between carotid disease and cognitive impairment but direct evidence is lacking. Revascularization may offer cognitive benefits but the effect is likely subtle and affected by the choice of revascularization procedure., Conclusions: Integrating cognitive outcomes into ongoing randomized controlled trials such as the nested CREST-H arm of the CREST-2 trial hold promise for offering new insight into the role of carotid artery stenosis and carotid revascularization on cognition., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Recently the Society for Vascular Surgery (SVS) and Society for Thoracic Surgeons (STS) published contemporary guidelines clearly defining complicated versus uncomplicated acute type B aortic dissections (TBADs) with an additional high-risk grouping. Few studies have evaluated outcomes associated with "high-risk" TBADs. The objective of this study was to assess differences in demographics, clinical presentation, symptom onset, and outcomes in high-risk patients that underwent either thoracic endovascular aortic repair (TEVAR) or best medical management for acute TBAD compared to those with complicated and uncomplicated acute TBAD., Methods: Patients admitted with acute TBADs from a single academic medical center from October 2011 to March 2020 were analyzed. Per the STS/SVS 2020 guidelines, high risk was defined as refractory pain/hypertension, bloody pleural effusion, aortic diameter >4 cm, false lumen diameter >22 mm, radiographic malperfusion, and early readmission, and complicated was defined as ruptured/malperfusion presentation. Uncomplicated patients were those without malperfusion/rupture and without high-risk features. The primary end-point was inpatient mortality. Secondary end-points included complications, reintervention, and survival., Results: Of the 159 patients identified with acute TBAD, 63 (40%) met the high-risk criteria. In the high-risk cohort, 38 (60%) underwent TEVAR (HR-TEVAR), with refractory pain as the most common indication, while 25 (40%) were managed medically (HR-medical). Malperfusion or rupture was present in 63 (40%) patients (complicated TBAD (C-TBAD)), all of whom underwent TEVAR. An additional 33 patients had no high-risk features and were all managed medically (uncomplicated TBAD). There were no differences in age, body mass index, and race between groups. Among the 4 groups, there were variable distributions in sex, insurance status, and incidence of several baseline comorbidities including congestive heart failure, chronic obstructive pulmonary disease, and renal dysfunction (P < 0.05 for all). C-TBAD had increased length of stay (12, interquartile range [IQR] 9-22) compared to HR-TEVAR (11.5, IQR 7-15), HR-medical (6, IQR 5-8), and uncomplicated TBAD (7, IQR 5-10) (P < 0.01). C-TBAD had decreased days from admission to repair (0, IQR 0-2) compared to HR-TEVAR (3.5, IQR 1-8) (P < 0.01). C-TBAD patients had worse 3-year survival compared to other groups (log-rank P < 0.01), although when in-hospital mortality was excluded, survival was similar among groups (P = 0.37). Of patients initially managed medically, outpatient TEVAR was performed in 6 (24%) HR-medical and 4 (12%) uncomplicated patients, with no difference between rate of intervention between groups (P = 0.22)., Conclusions: High-risk features, as defined in updated SVS/STS guidelines, are common in patients presenting with acute TBAD. High-risk patients had acceptable outcomes when managed either surgically or medically. High-risk patients that underwent TEVAR had improved perioperative outcomes and mortality compared to those undergoing TEVAR for C-TBAD, a finding which may help guide preoperative risk stratification and patient counseling., (Copyright © 2024 Elsevier Inc. All rights reserved.)

The pathogenesis of abdominal aortic aneurysm (AAA) formation involves vascular inflammation, thrombosis formation and programmed cell death leading to aortic remodeling. Recent studies have suggested that ferroptosis, an excessive iron-mediated cell death, can regulate cardiovascular diseases, including AAAs. However, the role of ferroptosis in immune cells, like macrophages, and ferroptosis-related genes in AAA formation remains to be deciphered. Single cell-RNA sequencing of human aortic tissue from AAA patients demonstrates significant differences in ferroptosis-related genes compared to control aortic tissue. Using two established murine models of AAA and aortic rupture in C57BL/6 (WT) mice, we observed that treatment with liproxstatin-1, a specific ferroptosis inhibitor, significantly attenuated aortic diameter, pro-inflammatory cytokine production, immune cell infiltration (neutrophils and macrophages), increased smooth muscle cell α-actin expression and elastic fiber disruption compared to mice treated with inactivated elastase in both pre-treatment and treatment after a small AAA had already formed. Lipidomic analysis using mass spectrometry shows a significant increase in ceramides and a decrease in intact lipid species levels in murine tissue compared to controls in the chronic AAA model on day 28. Mechanistically, in vitro studies demonstrate that liproxstatin-1 treatment of macrophages mitigated the crosstalk with aortic smooth muscle cells (SMCs) by downregulating MMP2 secretion. Taken together, this study demonstrates that pharmacological inhibition by liproxstatin-1 mitigates macrophage-dependent ferroptosis contributing to inhibition of aortic inflammation and remodeling during AAA formation.

Background: Sarcopenia is associated with adverse perioperative outcomes in patients undergoing operations for malignancy, but its influence on patients undergoing elective colectomy for diverticulitis is unknown. We hypothesized that sarcopenia is associated with adverse perioperative events in patients undergoing elective colectomy for diverticulitis., Methods: Comorbidities, operative characteristics, and postoperative complications were extrapolated from our institutional EMR in patients undergoing elective colectomy for diverticulitis from 2016 to 2020. Sarcopenia was calculated using perioperative imaging and defined by standard skeletal muscle index (SMI) and psoas muscle index (PMI) thresholds. Univariate analysis was used to compare sarcopenic and non-sarcopenic patients., Results: 148 patients met inclusion criteria. Using SMI thresholds, 95 patients (64%) were sarcopenic. With SMI criteria, sarcopenic patients were older (67 vs 52 years old; P < .01) and had lower BMIs (26.2 vs 34.0, respectively; P < .001) than non-sarcopenic patients. There were no differences in baseline characteristics, postoperative complications, and non-home discharge between groups ( P > .05 for all). Postoperative length of stay was greater in sarcopenic patients (3 IQR 2-5 vs 2 IQR 2-3 days; P < .01). Using PMI thresholds, 68 (46%) met criteria for sarcopenia. Using PMI thresholds, sarcopenic patients were older (68 vs 57.5 years old; P < .01) and had lower BMIs (25.8 vs 32.8; P < .01). There were no differences in comorbidities or measured operative outcomes between groups ( P > .05 for all), other than postoperative length of stay which was longer in the sarcopenic group (3.5 IQR 3-5 vs 2 IQR 2-3; P < .01)., Conclusions: Incidence of sarcopenia was high in patients undergoing elective colectomy for diverticulitis in our practice, but sarcopenia was not associated with adverse perioperative outcomes. In select patients, elective colectomy for diverticulitis can be safely performed in the presence of sarcopenia., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Exercise therapy is first-line treatment for intermittent claudication due to peripheral artery disease. We sought to synthesize the literature on sex differences in response to exercise therapy for the treatment of intermittent claudication due to peripheral artery disease. A scoping review was performed (1997 to 2023) using Ovid MEDLINE, CINAHL (Cumulative Index to Nursing and Allied Health Literature), Embase, SPORTDiscus, and Web of Science. Articles were included if they were a scientific report of any measures of health-related quality of life or walking performance after an intervention that included a structured walking program. Of the 13 studies, 11 included measures of walking distance; 7 included measures of walking time, 5 included measures of walking speed, and 4 included quality of life measures. Overall, exercise therapy resulted in significant improvements across most measures of walking performance for both men and females. When comparing magnitudes of outcome improvement by sex, results of walking-based measures were contradictory; some studies noted no difference and others found superior outcomes for men. Results of quality of life-based measures were also contradictory, with some finding no difference and others reporting substantially more improvement for females. Both men and females experienced considerable improvement in walking performance and quality of life with exercise therapy. Evidence regarding the differential effect of exercise therapy on outcomes by sex for intermittent claudication is limited and contradictory. Further efforts should be directed at using standardized interventions and metrics for measuring the outcomes that match the indications for intervention in these patients to better understand the expected benefits and any variance according to sex., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: Traditionally, acute uncomplicated type B aortic dissections are managed medically, and acute complicated dissections are managed surgically. Self-pay patients with medically managed acute uncomplicated type B aortic dissections may fare worse than their insured counterparts., Methods: In this single-center, retrospective cohort study, demographics, follow-up, and outcomes of patients with acute type B aortic dissections from 2011 to 2020 were analyzed., Results: In total, 159 patients presented with acute type B aortic dissections; 102 were complicated and managed with thoracic endovascular aortic repair, and 57 were uncomplicated and managed medically. A total of 32% (n = 51) were self-pay. Self-pay patients were from areas with worse area deprivation indices (71% vs 63%, P = .024). They more often reported alcohol abuse (28% vs 7%, P < .001), cocaine/methamphetamine use (16% vs 5%, P = .028), and nonadherence to home antihypertensives (35% vs 11%, P < .001). Self-pay patients less often had a primary care physician (65% vs 7%, P < .001) or took antihypertensives before admission (31% vs 58%, P = .003). Self-pay patients frequently required financial assistance at discharge (63%), most often using charity funds (46%). Few patients (7%) qualified for our hospital's financial assistance program, and most (78%) remained uninsured at the first follow-up. Self-pay acute uncomplicated type B aortic dissections patients had the lowest rate of follow-up (31% vs 66%, P < .001) and were more likely to represent emergently (75% vs 0%, P = .033) compared to insured acute uncomplicated type B aortic dissections patients. Self-pay patients were more likely to follow up after thoracic endovascular aortic repair for acute complicated type B aortic dissections (82% vs 31%, P < .001)., Conclusion: Self-pay patients have multiple, interconnected, complex socioeconomic factors that likely influence preadmission risk for dissection and post-discharge adherence to optimal medical management. Further research is needed to clarify treatment strategies in this high-risk group., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: Endovascular repair of thoracoabdominal aortic aneurysms (TAAA) and juxtarenal aortic aneurysms (JAA) with fenestrated and/or branched endografts (B/FEVAR) has become common. Physician modified endografts for patients presenting with symptomatic or contained ruptures has made B/FEVAR a feasible option in nonelective settings. The purpose of this study was to describe our 10-year institutional experience with endovascular interventions for TAAA in elective and nonelective cases to evaluate differences in outcomes and the clinical risk factors associated with nonelective presentation., Methods: A prospectively maintained database was retrospectively queried for patients undergoing B/FEVAR for TAAA and JAA at a single tertiary care academic institution between 1/2011 and 12/2020. Data collected included demographics, comorbidities, presenting symptoms, aneurysm characteristics, and clinical outcomes. Nonelective repair was defined as any patient that presented through the Emergency Department, as a hospital transfer, or as a direct admission from clinic and had aortic repair performed during the same admission. Univariate analyses were used to compare patients. The primary outcomes were 30-day and 1-year mortality. Secondary outcomes included perioperative complications and nonhome discharge., Results: Between 1/201 and 12/2020, a total of 208 patients underwent B/FEVAR for TAAA (173) and JAA (35). Nonelective repair was performed in 44 (21%) patients with 39 for TAAA (23%) and 5 for JAA (14%). Nonelective patients were younger (71 ± 11 vs. 74 ± 7 years, P = 0.03), more likely to be self-pay or have Medicaid (11% vs. 2%, P = 0.02) and had a different race distribution compared to the elective cohort (P < 0.01). Thirty-day mortality was 4% (n = 6) in elective repairs and 7% (n = 3) in nonelective repairs. One-year mortality was 13% (n = 22) in elective repairs and 18% (n = 8) in nonelective repairs. There were no differences between patients receiving elective versus nonelective repair in 30-day (P = 0.40) or 1-year mortality (P = 0.47). Nonelective patients had longer median duration of stay (11 interquartile range (IQR) 6-15 vs. 5 IQR 4-8, P < 0.01), postoperative length of stay (7 IQR 5-12 vs. 4 IQR 3-7, P < 0.01), and more intensive care unit days (6 IQR 3-8 vs. 3 IQR 2-5, P < 0.01). There were no differences in other secondary outcomes between elective and nonelective patients including inpatient and access-related complications, re-interventions, and nonhome discharge (P > 0.05 for all comparisons). A composite "any complication" occurred more frequently in patients with nonelective repair (50% vs. 35%, P = 0.03)., Conclusions: Endovascular repair for TAAA or JAA is a good option in patients undergoing nonelective surgical intervention, with comparable 30-day mortality, 1-year mortality, and perioperative morbidity to that of patients undergoing elective B/FEVAR., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: Operating rooms contribute up to 70% of total hospital waste. Although multiple studies have demonstrated reduced waste through targeted interventions, few examine processes. This scoping review highlights methods of study design, outcome assessment, and sustainability practices of operating room waste reduction strategies employed by surgeons., Methods: Embase, PubMed, and Web of Science were screened for operating room-specific waste-reduction interventions. Waste was defined as hazardous and non-hazardous disposable material and energy consumption. Study-specific elements were tabulated by study design, evaluation metrics, strengths, limitations, and barriers to implementation in compliance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews guidelines., Results: A total of 38 articles were analyzed. Among them, 74% of studies had pre- versus postintervention designs, and 21% used quality improvement instruments. No studies used an implementation framework. The vast majority (92%) of studies measured cost as an outcome, whereas others included disposable waste by weight, hospital energy consumption, and stakeholder perspectives. The most common intervention was instrument tray optimization. Common barriers to implementation included lack of stakeholder buy-in, knowledge gaps, data capture, additional staff time, need for hospital or federal policies, and funding. Intervention sustainability was discussed in few studies (23%) and included regular waste audits, hospital policy change, and educational initiatives. Common methodologic limitations included limited outcome evaluation, narrow scope of intervention, and inability to capture indirect costs., Conclusion: Appraisal of quality improvement and implementation methods are critical for developing sustainable interventions for reducing operating room waste. Universal evaluation metrics and methodologies may aid in both quantifying the impact of waste reduction initiatives and understanding their implementation in clinical practice., (Copyright © 2023 Elsevier Inc. All rights reserved.)

The mechanisms contributing to collective attention in humans remain unclear. Research indicates that pedestrians utilise the gaze direction of others nearby to acquire environmentally relevant information, but it is not known which, if any, additional social cues influence this transmission. Extending upon previous field studies, we investigated whether gaze cues paired with emotional facial expressions (neutral, happy, suspicious and fearsome) of an oncoming walking confederate modulate gaze-following by pedestrians moving in a natural corridor. We found that pedestrians walking alone were not sensitive to this manipulation, while individuals traveling together in groups did reliably alter their response in relation to emotional cues. In particular, members of a collective were more likely to follow gaze cues indicative of a potential threat (i.e., suspicious or fearful facial expression). This modulation of visual attention dependent on whether pedestrians are in social aggregates may be important to drive adaptive exploitation of social information, and particularly emotional stimuli within natural contexts.

Wilms tumor (WT) is the most common childhood kidney cancer and retains gene expression profiles reminiscent of the embryonic kidney. We have shown previously that CITED1, a transcriptional regulator that labels the self-renewing, multipotent nephron progenitor population of the developing kidney, is robustly expressed across all major WT disease and patient characteristics. In this malignant context, CITED1 becomes enriched in the nucleus, which deviates from its cytosolic predominance in embryonic nephron progenitors. We designed the current studies to test the functional and mechanistic effects of differential CITED1 subcellular localization on WT behavior. To mimic its subcellular distribution observed in clinical WT specimens, CITED1 was misexpressed ectopically in the human WT cell line, WiT49, as either a wild-type (predominantly cytosolic) or a mutant, but transcriptionally active, protein (two point mutations in its nuclear export signal, CITED1ΔNES; nuclear-enriched). In vitro analyses showed that CITED1ΔNES enhanced WiT49 proliferation and colony formation in soft agar relative to wild-type CITED1 and empty vector controls. The nuclear-enriched CITED1ΔNES cell line showed the greatest tumor volumes after xenotransplantation into immunodeficient mice (n=15 animals per cell line). To elucidate CITED1 gene targets in this model, microarray profiling showed that wild-type CITED1 foremost upregulated LGR5 (stem cell marker), repressed CDH6 (early marker of epithelial commitment of nephron progenitors), and altered expression of specific WNT pathway participants. In summary, forced nuclear enrichment of CITED1 in a human WT cell line appears to enhance tumorigenicity, whereas ectopic cytosolic expression confers stem-like properties and an embryonic phenotype, analogous to the developmental context.

Pedestrian crowds can form the substrate of important socially contagious behaviors, including propagation of visual attention, violence, opinions, and emotional state. However, relating individual to collective behavior is often difficult, and quantitative studies have largely used laboratory experimentation. We present two studies in which we tracked the motion and head direction of 3,325 pedestrians in natural crowds to quantify the extent, influence, and context dependence of socially transmitted visual attention. In our first study, we instructed stimulus groups of confederates within a crowd to gaze up to a single point atop of a building. Analysis of passersby shows that visual attention spreads unevenly in space and that the probability of pedestrians adopting this behavior increases as a function of stimulus group size before saturating for larger groups. We develop a model that predicts that this gaze response will lead to the transfer of visual attention between crowd members, but it is not sufficiently strong to produce a tipping point or critical mass of gaze-following that has previously been predicted for crowd dynamics. A second experiment, in which passersby were presented with two stimulus confederates performing suspicious/irregular activity, supports the predictions of our model. This experiment reveals that visual interactions between pedestrians occur primarily within a 2-m range and that gaze-copying, although relatively weak, can facilitate response to relevant stimuli. Although the above aspects of gaze-following response are reproduced robustly between experimental setups, the overall tendency to respond to a stimulus is dependent on spatial features, social context, and sex of the passerby.

This paper reviews the relationship between scientific evidence, uncertainty, risk and regulation. Risk has many different meanings. Furthermore, if risk is defined as the likelihood of an event happening multiplied by its impact, subjective perceptions of risk often diverge from the objective assessment. Scientific evidence may be ambiguous. Scientific experts are called upon to assess risks, but there is often uncertainty in their assessment, or disagreement about the magnitude of the risk. The translation of risk assessments into policy is a political judgement that includes consideration of the acceptability of the risk and the costs and benefits of legislation to reduce the risk. These general points are illustrated with reference to three examples: regulation of risk from pesticides, control of bovine tuberculosis and pricing of alcohol as a means to discourage excessive drinking.

This review explores the relation between evolution, ecology, and culture in determining human food preferences. The basic physiology and morphology of Homo sapiens sets boundaries to our eating habits, but within these boundaries human food preferences are remarkably varied, both within and between populations. This does not mean that variation is entirely cultural or learned, because genes and culture may coevolve to determine variation in dietary habits. This coevolution has been well elucidated in some cases, such as lactose tolerance (lactase persistence) in adults, but is less well understood in others, such as in favism in the Mediterranean and other regions. Genetic variation in bitter taste sensitivity has been well documented, and it affects food preferences (eg, avoidance of cruciferous vegetables). The selective advantage of this variation is not clear. In African populations, there is an association between insensitivity to bitter taste and the prevalence of malaria, which suggests that insensitivity may have been selected for in regions in which eating bitter plants would confer some protection against malaria. Another, more general, hypothesis is that variation in bitter taste sensitivity has coevolved with the use of spices in cooking, which, in turn, is thought to be a cultural tradition that reduces the dangers of microbial contamination of food. Our evolutionary heritage of food preferences and eating habits leaves us mismatched with the food environments we have created, which leads to problems such as obesity and type 2 diabetes.

A key assumption underlying any management practice implemented to aid wildlife conservation is that it will have similar effects on target species across the range it is applied. However, this basic assumption is rarely tested. We show that predictors [nearly all associated with agri-environment scheme (AES) options known to affect European birds] had similar effects for 11 bird species on sites with differing farming practice (pastoral vs. mixed farming) or which differed in the density at which the species was found. However, predictors from sites in one geographical region tended to have different effects in other areas suggesting that AES options targeted at a regional scale are more likely to yield beneficial results for farmland birds than options applied uniformly in national schemes. Our study has broad implications for designing conservation strategies at an appropriate scale, which we discuss.

House-sparrow populations have declined sharply in Western Europe in recent decades, but the reasons for this decline have yet to be identified, despite intense public interest in the matter. Here we use a combination of field experimentation, genetic analysis and demographic data to show that a reduction in winter food supply caused by agricultural intensification is probably the principal explanation for the widespread local extinctions of rural house-sparrow populations in southern England. We show that farmland populations exhibit fine-level genetic structuring and that some populations are unable to sustain themselves (sinks), whereas others act as sources.

In recent years, there has been much concern in the UK about population declines of widespread species in agricultural habitats. Conservation-orientated research on declining birds has focused on vital rates of survival and productivity. However, the environmental factors which may influence movements between populations of widespread species is poorly understood. Population genetic structure is an indirect description of dispersal between groups of individuals. To attempt to develop an understanding of genetic structuring in a widespread, but declining, farmland bird, we therefore investigated the yellowhammer, Emberiza citrinella, population in England and Wales using microsatellite data. Our first aim was to investigate whether there was genetic substructuring in the population. A second aim was to investigate if there was a relationship between genetic distances and various environmental variables. Finally, we analysed the microsatellite data for evidence of loss of genetic variation due to population decline. Our data showed a slight but significant structure within the yellowhammer population. This therefore cannot be considered a panmictic population. Our example from South Cumbria implies that high-altitude barriers may have a slight influence on population structure. However, on the whole, genetic distances between sample sites were not significantly correlated with geographical distances, degrees of population connectivity, high altitudes, or differences in precipitation between sites. Finally, we detected departures from mutation-drift equilibrium (excess heterozygosity), which is indicative of a loss of genetic variation through recent decline.

Volumetric studies in a range of animals (London taxi-drivers, polygynous male voles, nest-parasitic female cowbirds, and a number of food-storing birds) have shown that the size of the hippocampus, a brain region essential to learning and memory, is correlated with tasks involving an extra demand for spatial learning and memory. In this paper, we report the quantitative advantage that food storers gain from such an enlargement. Coal tits (Parus ater) a food-storing species, performed better than great tits (Parus major), a nonstoring species, on a task that assessed memory persistence but not on a task that assessed memory resolution or on one that tested memory capacity. These results show that the advantage to the food-storing species associated with an enlarged hippocampus is one of memory persistence.

The organisation and work of the Food Standards Agency are described. The Agency is a new non-Ministerial Government department with responsibility for protecting the health of the public and other interests of consumers in relation to food. Its roles encompass assessment of risk (through scientific expert committees) as well as risk communication and management. Among the many changes that the Agency has brought about is a new commitment to openness. All policy discussions and decisions take place in public. Diet and bovine spongiform encephalopathy are used as examples to illustrate the Agency's approaches to dealing with risk and uncertainty.

The distributions of one neurotransmitter, two neurotransmitter-related substances, and five neuropeptides were examined within the homing pigeon caudolateral neostriatum (NCL). All eight neuroactive substances were found within a tyrosine hydroxylase (TH)-dense region that defines the NCL. Overall regional variation in the relative density of these substances suggested at least two neurochemically distinct portions of NCL. Dorsal NCL contained relatively dense staining for TH, choline acetyltransferase, and substance P, whereas vasoactive intestinal polypeptide was more abundant in ventral portions of NCL. Serotonin and cholecystokinin were found to be densest in intermediate portions of NCL. Somatostatin and leucine-enkephalin were homogeneously distributed throughout NCL. The results suggest that NCL may consist of multiple subdivisions. Investigations into the behavioral importance of these regions are necessary to clarify the role of this brain region in avian behavior., (Copyright 1999 Wiley-Liss, Inc.)

It is known from previous work that neurones are born continuously in the ventricular zone of the bird brain. In this study, we show that the amount of cell proliferation in the ventricular zone of the hippocampus (HP) and the hyperstriatum ventrale (HV) is influenced by behavioural experience. Two groups of birds (marsh tits) were compared: those allowed to store and retrieve food once every 3 days between days 35 and 56, and age-matched controls treated in an identical way, except that they were not allowed to store and retrieve food. After three trials of storing and retrieval, between days 35 and 41 posthatch, experienced birds showed a significantly higher rate of cell proliferation than did controls. The experienced birds also showed a significant increase in total cell and neuronal number by day 56 posthatch, after eight trials of storing and retrieval. There were no significant differences in the amount of programmed cell death in the hippocampus in this study. In a novel analysis of the data we demonstrate that the effect of experience between days 35 and 41 was to increase the daily rate of neurogenesis in the ventricular zone from 3.9 to 10%, and that this change could account for the increase in total hippocampal neuronal number by day 56 in the experienced birds. Thus, the observed increase in hippocampal volume and neuronal number as a result of food storing and retrieval, may be caused by an increase in neurogenesis in the first few trials of food storing experience.

The avian hippocampal formation (Hf) plays an important role in spatial memory for food storing. Here we examined the effects of excitotoxic lesions of the Hf and subsequent neural transplantation on a one-trial associative memory task in zebra finches. The results showed (1) that small ibotenic acid lesions of the dorsal Hf of zebra finches produced significant spatial memory impairments compared with controls, sham-lesioned birds, and prelesion performance; and (2) that Hf-lesioned birds given transplants of embryonic hippocampal (H) tissue, but not those given transplants of embryonic anterior telencephalon (AT) tissue, showed a significant reversal of the performance deficits on the spatial memory task. Lesioned-only birds and lesioned birds given H or AT transplants that did not survive did not show behavioral improvement. Sham-lesioned and untreated control birds maintained good performance throughout the experiment. The H and AT transplants were found to be growing partially within the Hf and partially within the underlying ventricle. The transplants appeared healthy and contained neurons with beaded and unbeaded fibers (shown by immunohistochemistry with antibodies to parvalbumin, substance P, and a 200 kDa neurofilament protein). Blood vessels and erythrocytes were also present within the transplants. The results show that neural transplants can survive within the bird brain and that small lesions of the Hf produce significant spatial memory deficits that can only be reversed by surviving homologous H transplants, and not by heterologous telencephalon transplants.

We tested the hypothesis that experience of migration from Europe to tropical Africa by Garden Warblers is associated with changes in the relative volume of the hippocampus, a brain region thought to be involved in processing spatial information, including that used in navigation. Relative hippocampal volume was larger in birds at least one year old that had migrated to and from Africa, than in naive birds approx. 3 months old. Further comparisons between groups of differing age and experience of migration suggested that both experience and age during the first year have an effect of relative hippocampal volume. The increase in relative hippocampal volume was mainly due to a decrease in the size of the telencephalon; however, the comparison between young, naive birds and older, experienced birds also suggests a possible increase in absolute hippocampal volume. The latter is associated with an increase in number and density of neurons, whilst the former is associated with an increase in density but no change in total number of neurons. In a non-migratory close relative of the garden warbler, the Sardinian warbler, older birds had a smaller telencephalon but there was no change in hippocampal volume, which supports the view that changes in the hippocampus may be associated with migratory experience, whilst changes in the telencephalon are not.

The avian hippocampal formation (HP) is considered to be homologous to the mammalian hippocampus, being involved in memory formation and spatial memory in particular. The subdivisions and boundaries of the pigeon hippocampus have been defined previously by various morphological methods to detect further similarities with the mammalian homologue. We studied the efferent projections of the zebra finch hippocampus by applying Phaseolus vulgaris leucoagglutinin, and three main subdivisions were distinguished on the basis of the connectivity patterns. Dorsolateral injections gave rise to projections innervating the rostralmost extension of the HP, a laminar complex including the dorsal and ventral hyperstriata and the lamina frontalis superior, the rostral lobus parolfactorius, the medial and ventral paleostriatal regions, the lateral septal nucleus, the nucleus of the diagonal band, the dorsolateral corticoid area, the archistriatum posterius, and the nucleus taeniae in the telencephalon. In the diencephalon, labelled axons were seen in the periventricular and lateral hypothalamus, including the lateral mammillary nuclei, and in the dorsolateral and the dorsomedial posterior thalamic nuclei, whereas, in the midbrain, only the area ventralis of Tsai contained hippocampal fibres. With the exception of the bilateral archistriatal efferents, all projections were ipsilateral. Dorsomedial injections gave rise to a local fibre system that was almost completely restricted to the ipsilateral hippocampal formation. In addition, lectin-containing fibres continued in the dorsal septal region and a thin band in the hyperstriatum accessorium, adjacent to the lateral ventricle. Ventral injections gave rise to axons innervating ipsilaterally the dorsolateral subdivision, and bilaterally the medial septal nuclei and the contralateral ventral hippocampus.

Operant studies on pigeons using slide-projected images suggest that photographs of geographical locations might be used as a research tool to study the importance of visual landmarks in homing. Before using this method, however, it is necessary to show that pigeons do see photographic slides as representing real world locations. After reviewing the evidence for picture-to-object correspondence for geographical locations in pigeons, we report the results of an experiment designed to test whether outdoor experience at a location affected homing pigeons' ability to categorise slides of that versus another location displayed in an operant set-up. Four birds visited one location immediately before each experimental session; four birds visited an irrelevant location. No effect of outdoor experience was found on acquisition, or transfer to novel stimuli. The possible reasons for limitations on picture-to-object correspondence are discussed.

Neurones in the zebra finch dorsal forebrain (hippocampal and lateral corticoid complexes) were described and located using Golgi methods. We distinguish two main classes of neurones, spinous with distant projecting axons, and aspinous with local axons. Spinous neurones are subclassified into bitufted pyramids, localised in the medial hippocampus, modified bitufted pyramids in the intermediate corticoid area, multipolar neurones in the parahippocampal area, lateral hippocampus and corticoid complex, and stellate neurones in the corticoid complex. Among the aspinous neurones, we distinguish neurones with basket axons, dense pericellular axons, radial axons, and net-like axons, and horizontal cells seen in the dorsolateral corticoid area. This group includes sparsely spinous neurones found in the intermediate corticoid area. On the basis of the neuronal characteristics, we divide the hippocampal complex into 5 fields: medial and lateral hippocampus, parahippocampal area, central field of the parahippocampal area, and crescent field. The lateral corticoid complex is subdivided into an intermediate corticoid area and a dorsolateral corticoid area. We conclude that the avian dorsal forebrain is an assembly of fields interconnected by axonal collaterals. The medial hippocampus and possibly the intermediate corticoid area display a primitive cortex-like organisation, whereas the other fields lack any sign of cortical structure.

Food storing passerines have a larger hippocampus, relative to the rest of the telencephalon and/or body mass, than do non-storing species. This study looked at the relationship between relative size of the hippocampus and degree of food storing in six species of Paridae (blue tit, Parus caeruleus, great tit, P major, marsh tit, P palustris, coal tit, P ater, black-capped chickadee, P. atricapillus, and willow tit, P montanus). The degree of storing by these species varies from little or none to thousands of food items. The period over which food is stored also varies from a few hours to several months. The results showed that hippocampal volume, relative to the rest of the telencephalon, is larger in those species that store more food, store for longer, or both. In an analysis of intraspecific variation within two of the species, the food storing marsh tit and the non-storing blue tit, there was a significant positive relationship between hippocampal volume relative to body mass, and telencephalic volume relative to body mass, in the marsh tit but no relationship between these variables in the blue tit.

Birds that store food have a relatively large hippocampus compared to non-storing species. The hippocampus shows seasonal differences in neurogenesis and volume in black-capped chikadees (Parus atricapillus) taken from the wild at different times of year. We compared hippocampal volumes in black-capped chickadees captured at the same time but differing in food-storing behaviour because of manipulations of photoperiod in the laboratory. Differences in food-storing behaviour were not accompanied by differences in the volume of the hippocampus. Hippocampal volumes also did not differ between two groups of a non-food-storing control species, house sparrows (Passer domesticus), exposed to the same conditions as the chickadees.

As a result of natural history studies, it has been hypothesized that food-storing birds may develop a special kind of memory to cope with the demand imposed by their food-storing behaviour (i.e. the ability to retrieve food from a wide variety of stores over varying amounts of time after storage). Recent studies on food-storing birds suggest that, at a relatively late stage in their development, the specific memories associated with food-storing behaviour can stimulate growth of the hippocampus, an area of the brain concerned with memory processing.

Hand-raised marsh tits (Parus palustris) were exposed to experience of storing and retrieving food at three different ages (35-59, 60-83, 115-138 days posthatch). At equivalent ages, control birds were given identical experience except for storing and retrieving food. Volumetric analysis was carried out to measure the hippocampal region, ectostriatum, and telencephalon of experienced and control birds. Individuals with experience of storing and retrieving food had a larger hippocampal region relative to the rest of the telencephalon than did controls, independent of age. The hippocampal region of experienced birds also contained more neurons and fewer apoptotic cells than that of controls. No volumetric differences were observed in ectostriatum, which served as a control brain region. The results suggest that some aspect of food-storing and retrieval directly influences growth and attrition of the hippocampal region in food-storing birds.

Food storing birds have been shown to have a larger hippocampus, relative to the rest of the telencephalon, than do non-storers. A previous study reported that this difference in relative hippocampal volume is not apparent in a comparison of nestling birds, but emerges after birds have fledged. This conclusion was based on a comparison of a storing and a non-storing species in the corvid family. The present study compared another storer/non-storer pair of species in order to test whether the results of the previous study can be replicated in another family of birds. The volumes of the hippocampal region and remainder of the telencephalon were measured and estimates of neuron size, density and total number in the hippocampal region were made for nestlings and adults of the food-storing marsh tit Parus palustris and non-storing blue tit Parus caeruleus. Relative hippocampal volume did not differ between nestlings of the two species, whilst the relative hippocampal volume of adult marsh tits was greater than that of blue tits. The difference between adults arose because in marsh tits but not blue tits, adults had a significantly larger relative hippocampal volume than did nestlings. Neuron density was significantly higher in both species in nestlings than in adults and adult blue tits had fewer neurons than did adult marsh tits. The results of this study are largely consistent with the earlier study comparing a storing and non-storing species of corvid, suggesting that the observed patterns may reflect a general difference between storers and non-storers in the development of the hippocampal region.

Song and brain structure are compared amongst 41 species of oscine birds by using the method of independent evolutionary contrasts. We find a significant correlation between the relative volume of the song control centre, the high vocal centre (HVC), and the number of song types typically found in the repertoire. Relative HVC volume is not correlated with the number of different syllable types per song bout. The relative volume of a second song nucleus, area X, is not significantly correlated with either measure. Relative HVC volume is uncorrelated with relative volume of the hippocampus, a brain area involved in other forms of memory. This is the first evidence for repeated independent evolution of an association between complexity of learned song and the relative volume of one of the song control nuclei though to be involved in song learning.

The distribution of zinc was studied in the brain of the zebra finch (Taenopygia guttata) by means of the selenium histochemical method. A specific pattern was seen, which usually correlated with the main known architectonic subdivisions. In addition, a few as yet unidentified structures were observed. In the telencephalon, the pallial components were stained with moderate to strong intensity. The only exceptions were the hyperstriatum intercalatus superior, a small medial area in the hyperstriatum accessorium and in the dorsolateral cortex, and the dorsomedial part of the hippocampal complex, which were virtually devoid of staining. Staining of the dorsal ventricular ridge components varied considerably. The archistriatum, the nucleus accumbens, the nucleus of the stria terminalis, the hyperstriatum ventrale and the lateral septum showed moderate to strong staining. The medial septum was weakly stained. The neostriatum showed a rather complex pattern of staining with unstained areas, such as the magnocellular nucleus of the anterior neostriatum, and other parts intensely stained, especially in its caudal region. Both paleostriatii primitivum and augmentatum showed a rostro-caudal gradient that was increasingly stained. We also observed an intensely stained area ventral to the fasciculus prosencephali lateralis and lateral to the tractus septomesencephalicus, a weakly to moderately stained band ventral to the lobus parolfactorius, an intensely stained zone along the lateral ventricle in the hyperstriatum ventrale, and an unstained almond-shaped nucleus in the lateral hyperstriatum ventrale. In the diencephalon, the hypothalamus showed a moderate to strong, rather uniform staining, whereas the thalamus was usually weakly to moderately stained, with the exception of a few unstained nuclei. Only the lateral nucleus of the habenula was stained, and with strong intensity. Most of the mesencephalon stained rather uniformly with a moderate to strong intensity. The most intense staining was seen in the substantia grisea centralis, the substantia grisea et fibrosa periventricularis, the torus semicircularis and the nucleus intercollicularis. The tectum opticum was virtually devoid of stain except for two light bands in the stratum griseum et fibrosum superficiale. The formatio reticularis was moderately stained. All the other structures were either weakly stained or unstained. Some staining was seen in the Purkinje and the granular layers of the cerebellum, as well as around its internal nuclei. The pons and the medulla oblongata showed an overall moderate to intense staining, with the exception of a few unstained nuclei. When compared in three bird species belonging to different genera, zinc distribution shows remarkable similarities, despite species, age and methodological differences.(ABSTRACT TRUNCATED AT 400 WORDS)

The avian hippocampal formation (HP) is thought to play a role in the processing of spatial memory related to food-storing behaviour. The HP of two food-storing species (marsh tit (Parus palustris) and magpie (Pica pica)) and two non-storing species (great tit (Parus major) and jackdaw (Corvus monedula)) were compared following calbindin-like immunostaining. In the dorsal hippocampal region, both species of food-storing birds had larger calbindin-immunoreactive cells than did the two non-storing species. The fact that this association between storing behaviour and cell morphology is seen in two unrelated families of birds, the Paridae (marsh tit versus great tit) and Corvidae (magpie versus jackdaw) suggests that there may be a direct link between food-storing behaviour and the dorsal hippocampal calbindin-immunoreactive cell population.

Previous studies demonstrated that amongst food-storing passerine birds the hippocampal region (dorso-medial cortex) is enlarged relative to the rest of the telencephalon. It has been hypothesised that this hippocampal specialisation is related to the spatial memory requirements of retrieving large numbers of stored items. Here we compare the development of the hippocampus in a food-storing and a non-storing corvid, the adults of which differ in relative hippocampal volume. The volume, cell density and number of cells in the hippocampal region of nestling (5-25 days post hatching) and adult (> 320 days old) magpies Pica pica (food-storing) and jackdaws Corvus monedula (non-storing) were measured. In both species the volume of the hippocampus increases with the volume of the rest of the telencephalon during the nestling growth phase. The relative volume of the hippocampus in 5- to 25-day-old nestlings of the two species does not differ significantly. In the food-storing magpie, the relative volume of the adult hippocampus is significantly larger than that of nestlings, whilst in the jackdaw, adults and nestlings do not differ. The density of neurons declines with increasing age and this effect is more marked in jackdaws than in magpies. Neuron number did not change significantly with age, but is significantly greater in adult magpies than in adult jackdaws. These results are discussed in relation to the possibility that changes in hippocampal volume and cell number are related to the use of spatial memory in retrieving stored food.

The ability of two species of tits to remember the location and/or features of an object was tested in a delayed-matching-to-sample procedure. Three values of retention interval between presentation of the sample stimulus and the choice--30 sec, 5 min, and 15 min--were used. Both species performed at above-chance level at all retention intervals, and there was no significant decline in accuracy with increasing interval. A pool of 100 stimulus objects was used, but the results of control trials indicated that the birds responded primarily to location rather than stimulus features of the object itself. Although the food-storing marsh tit tended to perform at a higher level than the non-storing great tit, the only significant difference between the species was in the first 50 trials of the first treatment, when the birds were acquiring the task. The results are discussed in relation to the hypothesized special memory capacity of food-storing birds.

The ideal free distribution, a theoretical model of the distribution of competitors between habitat patches, has recently undergone a number of modifications and extensions. These fall into two main categories: those that assume that equilibrium is attained, and those that establish whether it is attained. The modifications suggest ways in which behavioural properties of individuals might affect the distribution of competitors, and clear a path for further empirical tests., (Copyright © 1992. Published by Elsevier Ltd.)