Social identification moderates the effect of crowd density on safety at the Hajj

Crowd safety is a major concern for those attending and managing mass gatherings, such as the annual Hajj or pilgrimage to Mecca (also called Makkah). One threat to crowd safety at such events is crowd density. However, recent research also suggests that psychological membership of crowds can have positive benefits. We tested the hypothesis that the effect of density on safety might vary depending on whether there is shared social identification in the crowd. We surveyed 1,194 pilgrims at the Holy Mosque, Mecca, during the 2012 Hajj. Analysis of the data showed that the negative effect of crowd density on reported safety was moderated by social identification with the crowd. Whereas low identifiers reported reduced safety with greater crowd density, high identifiers reported increased safety with greater crowd density. Mediation analysis suggested that a reason for these moderation effects was the perception that other crowd members were supportive. Differences in reported safety across national groups (Arab countries and Iran compared with the rest) were also explicable in terms of crowd identification and perceived support. These findings support a social identity account of crowd behavior and offer a novel perspective on crowd safety management.The annual Hajj, or pilgrimage to Mecca (also called Makkah) in Saudi Arabia, is one of the world’s largest mass gatherings. The official number of pilgrims who attended in 2012, for example, was over 3 million. The safety of pilgrims has long been a concern to those organizing and attending the Hajj. The Hajj involves rituals at specified spiritual locations during a certain 5-d period each year. Given the number of people seeking to be in the same locations at the same time, therefore, one possible threat to crowd safety is the level of crowd density.The link between crowd density and risk to crowd safety has been suggested in a number of accounts (see, for example, refs. 1 and 2). High-density flows are said to be a proximal cause of crushing disasters at the Hajj (3). Thus, this was one explanation for the disaster in 2006 when 346 pilgrims died as they attempted to “stone the devil” (4). Furthermore, the period in which the number of pilgrims attending the Hajj doubled from 1 million to 2 million (i.e., 1982–2010) also saw a large number of major crowd disasters (1994, 1998, 2001, and 2004), which again suggests a link between crowd density and risk to crowd safety.Following these crowd disasters, considerable resources were invested in improving crowd safety at Hajj locations, including most notably the redesign of Jamaraat Bridge (5). Indeed, since 1992 over £200 billion has been spent on these projects (6). Although crowd safety has been hugely enhanced at the Hajj since 2006 and a more scientific approach to risk assessment has developed, arguably there has been a neglect of the positive potential of the crowd itself to crowd safety. Overwhelmingly, crowd safety solutions have been understood as purely technological in nature, comprising contributions from engineering, mathematics, and architecture, but not crowd psychology. In existing approaches to understanding and enhancing crowd safety at the Hajj, therefore, the crowd is either excluded or, worse, treated as simply an inherent source of pathology, for example, through “stampedes” and the spread of diseases (7, 8).An alternative perspective on crowd safety is suggested by the social identity approach in psychology (9). This approach has been applied to understanding a wide range of crowd phenomena, including crowding and “personal space” (10), urban riots (11), football crowds (12), protest demonstrations (13), mass emergency behavior (14), and audience experiences at music festivals (15). The social identity approach has also been applied to analyzing behavior at religious mass gatherings, through a program of research on the Indian Mela pilgrimage (16, 17).The social identity approach suggests that, as well as personal identities (which are unique and which differentiate us from other individuals), we have multiple social identities, which are based on our group or social category memberships (9). Sharing a social identity with others in a crowd—defining these others as “us” (or “in-group”) rather than “them”—has cognitive, behavioral, and affective consequences (18). Importantly, one of these consequences is increased expectations of social support from others in the crowd (14, 19, 20; cf. 21).In situations of high crowd density, dangers include that of falling and being trampled or, far more commonly, of being crushed while upright (1, 22). However, such dangers will be reduced where others are considerate and ready to come to one’s aid. Based on the previous research, we suggest that the expectation that there is such support will be enhanced where there is shared social identification in the crowd (23). If this formulation is correct, social identification should moderate the negative effect of crowd density on reported safety at the Hajj.However, these hypotheses have not yet been tested. Indeed, there is a distinct lack of social psychological research on mass gatherings. Although recent studies of the Hindu Mela investigated the role of social identification on factors, such as wellbeing (24), noise (25), and cold (26), they did not examine crowd density or safety issues. More specifically, very little social psychological research has been carried out on the Hajj, despite its huge cultural significance and the number of serious crowd accidents that have occurred there in the past. An exception is the study by Clingingsmith et al. (27); but this surveyed pilgrims only after traveling to Mecca, and provided no analysis of crowd behavior. Therefore, no previous study has examined the role of social psychological factors in crowd safety among pilgrims during the Hajj, which was the aim of the present study.     

Robot-assisted and fluoroscopy-guided pedicle screw placement: a systematic review

Purpose

At present, most spinal surgeons undertake pedicle screw implantation using either anatomical landmarks or C-arm fluoroscopy. Reported rates of screw malposition using these techniques vary considerably, though the evidence generally favors the use of image-guidance systems. A miniature spine-mounted robot has recently been developed to further improve the accuracy of pedicle screw placement. In this systematic review, we critically appraise the perceived benefits of robot-assisted pedicle screw placement compared to conventional fluoroscopy-guided technique.

Methods

The Cochrane Central Register of Controlled Trials, PubMed, and EMBASE databases were searched between January 2006 and January 2013 to identify relevant publications that (1) featured placement of pedicle screws, (2) compared robot-assisted and fluoroscopy-guided surgery, (3) assessed outcome in terms of pedicle screw position, and (4) present sufficient data in each arm to enable meaningful comparison (>10 pedicle screws in each study group).

Results

A total of 246 articles were retrieved, of which 5 articles met inclusion criteria, collectively reporting placement of 1,308 pedicle screws (729 robot-assisted, 579 fluoroscopy-guided). The findings of these studies are mixed, with limited higher level of evidence data favoring fluoroscopy-guided procedures, and remaining comparative studies supporting robot-assisted pedicle screw placement.

Conclusions

There is insufficient evidence to unequivocally recommend one surgical technique over the other. Given the high cost of robotic systems, and the high risk of spinal surgery, further high quality studies are required to address unresolved clinical equipoise in this field.     

Outcome of low body weight (<2.2 kg) infants undergoing cardiac surgery

Introduction

Infants with low body weight (LBW) following cardiac surgery are a major challenge for the post cardiac surgery care unit. It has been observed that post surgery outcome for LBW infants is worse compared to the outcome of normal body weight infants. A study was conducted to compare post operative course and outcome of infants with body weight of 2.2 kg or less against infants with normal body weight who underwent similar cardiac surgeries.

Methods

A retrospective review was performed for all infants below 2.2 kg who underwent cardiac operations at King Abdulaziz Cardiac Center from January 2001 to October 2011. Cases with LBW (Group A) were compared with matching group (Group B) of normal body weight infants who had similar cardiac surgeries and matching surgical risk category. The demographic, ICU parameters, complications, and short-term outcome of both groups were analyzed.

Results

Two groups were formed, with 37 patients in Group A, and 39 patients in Group B. Except for weight (2.13 ± 0.08 kg in Group A vs 3.17 ± 0.2 kg in Group B), there was no statistical difference in demographic data between both groups. Cardiac procedures included coarctation repair, arterial switch, ventricular septal defect (VSD) repair, tetralogy of Fallot repair, systemic to pulmonary shunt and Norwood procedures. Patients in Group A had statistically significant difference from Group B in terms of bypass time (p = 0.01), duration of inotropes (p = 0.01), duration of mechanical ventilation (p = 0.004), number of re-intubations (p = 0.015), PCICU length of stay (p = 0.007), and hospital mortality: 13.5% in Group A vs 0% in Group B (p value 0.02).

Conclusion

Patients with LBW (<2.2 kg) underwent cardiac surgery with overall satisfactory results, but with increased risk of ICU morbidity and mortality.     

Production of multienzyme by Bacillus aestuarii UE25 using ionic liquid pretreated sugarcane bagasse

The utilization of sugarcane bagasse (SB) in fermentation requires pretreatment processes to render fermentable components available to microorganisms. Pretreatment by using ionic liquids (ILs) is considered promising but the high cost is an impediment in its adoption, therefore, a mixture of IL pretreated and untreated SB was utilized to obtain bacterial multienzyme under solid-state fermentation (SSF). Bacillus aestuarii UE25, a thermophilic strain was utilized for that purpose. Fermentation conditions were optimized by adopting a central composite design. The model showed a good correlation between the predicted and the experimental values for amylase, xylanase, endoglucanase, and β-glucosidase. Volumetric and specific productivity of xylanase (4580 IU ml⁻¹ h⁻¹, 244.25 IU mg⁻¹ substrate, and 50 IU mg⁻¹ protein) were higher than the other enzymes. Changes in lignin content and reduced cellulose crystallinity due to IL pretreatment, followed by fermentation, were visualized by scanning electron microscopy, Fourier transform infrared spectroscopy, and Nuclear magnetic resonance. The strategy adopted by utilizing a mixture of IL pretreated and untreated SB under SSF proved promising to obtain high titers of different enzymes simultaneously. Since the bacterial strain used is thermophilic, therefore, the multienzyme can find its application in commercial processes which are carried out at high temperatures.     

Presentation outside office hours does not negatively influence treatment times for reperfusion therapy for acute ischemic stroke

Journal of Neurology - Treatment outside office hours has been associated with increased workflow times for intravenous thrombolysis (IVT) in acute ischemic stroke (AIS). Limited data suggest that...     

Increased serum levels of quinolinic acid indicate enhanced severity of hepatic dysfunction in patients with liver cirrhosis

Background

The Model for End-Stage Liver Disease (MELD) score is a tool for assessment of the degree of hepatic insufficiency/failure. Quinolinic acid (QuinA) is a tryptophan metabolite produced by activated macrophages. Here we investigate whether the degree of systemic inflammation (QuinA, neopterin, CRP and IL-6) correlates with clinical liver dysfunction according to the MELD Score.

Method

Ninety-four patients with liver cirrhosis were categorized into 2 groups according to baseline MELD score (group I, MELD <20, n = 61, and group II, MELD ?20, n = 33).

Results

Serum levels of QuinA, neopterin, CRP, and IL-6 significantly correlated with MELD score (r = 0.77, 0.75, 0.57, and 0.50; p < 0.0001, respectively). Patients of group II had significantly higher serum levels of QuinA, neopterin, CRP, and IL-6 than group I (p ? 0.0001). ROC curve analysis showed that QuinA and neopterin are more sensitive markers for severity of liver disease than established markers of inflammation such as CRP and IL-6 (sensitivity = 86% and 79%, respectively) (AUC = 0.89 and 0.89, respectively). QuinA provided the most sensitive index with regard to the identification of patients with hepatic encephalopathy.

Conclusion

Serum levels of QuinA reflect the degree of liver dysfunction. Moreover, high levels of QuinA may serve as a sensitive indicator of hepatic encephalopathy.