Spike sorting for large, dense electrode arrays

Developments in microfabrication technology have enabled the production of neural electrode arrays with hundreds of closely spaced recording sites, and electrodes with thousands of sites are under development. These probes in principle allow the simultaneous recording of very large numbers of neurons. However, use of this technology requires the development of techniques for decoding the spike times of the recorded neurons from the raw data captured from the probes. Here we present a set of tools to solve this problem, implemented in a suite of practical, user-friendly, open-source software. We validate these methods on data from the cortex, hippocampus and thalamus of rat, mouse, macaque and marmoset, demonstrating error rates as low as 5%

The Economic Roots of Anti-immigrant Prejudice in the Global South: Evidence from South Africa

Most research in developed countries on prejudice toward foreign-born minorities suggests that cultural rather than economic threat motivates xenophobia. Prior studies leave unanswered questions about the origins of anti-immigrant prejudice in developing countries, where one-third of worldwide immigration occurs. Alternatively, developing-country research simply assumes that economic threat drives prejudice in the global South but has not presented credible empirical evidence. In this study, we seek to reliably measure anti-immigrant prejudice and examine possible determinants of prejudice and prejudice-based voting behavior. Through a list experiment conducted on a random sample of South Africans (N = 1,088), we investigate the predictive power of economic threat theory in explaining prejudice toward immigrants in South Africa. The results show that significant prejudice toward immigrants exists among South Africans and that such prejudice is higher among the unemployed, but these sentiments do not seem to influence vote choice. The evidence suggests that the determinants of anti-immigrant sentiments due to South-South migration are distinct from South-North migration

Who Controls Foreign Aid? Elite versus Public Perceptions of Donor Influence in Aid-Dependent Uganda

Does foreign aid enable or constrain elite capture of public revenues? Reflecting on prominent debates in the foreign aid literature, we examine whether recipient preferences are consistent with a view that foreign donors wield substantial control over the flow of aid dollars, making elite capture more difficult and mass benefits more likely. We compare elite and mass support for foreign aid versus government spending on development projects through a survey experiment with behavioral outcomes. A key innovation is a parallel experiment on members of the Ugandan national parliament and a representative sample of Ugandan citizens. For two actual aid projects, we randomly assigned different funders to the projects. Significant treatment effects reveal that members of parliament support government programs over foreign aid, whereas citizens prefer aid over government. Donor control also implies that citizens should favor foreign aid more and elites less as their perceptions of government clientelism and corruption increase. We explore this and report on other alternative mechanisms. Effects for citizens and elites are most apparent for those perceiving significant government corruption, suggesting that both sets of subjects perceive significant donor control over aid

Taking to the Streets: Protest as an Expression of Political Preference in Africa

Between 2011 and 2014, there were 5 times as many protests per annum in Africa as there had been in 2000. The majority of these protests were related to deteriorating economic conditions, poor service delivery, inadequate wages, and economic inequality. These protests, which we term “valence protests,” do not fit easily into typical narratives about contentious behavior: they are neither social movements, nor revolutionary, nor a manifestation of organized labor—instead, many of these protests are a collective expression of a valence issue of which the government is well aware. We argue for a different conceptual framework for valence protests and contend that they are a way for politically engaged citizens to express their political preferences when voting is insufficient. Using Round 5 Afrobarometer data, we find empirical support for this claim. We also find that citizens more readily communicate political preferences through protest in countries governed by dominant parties

Symptoms and Stereotypes: Perceptions and Responses to Covid-19 in Malawi and Zambia

A large literature documents Covid-19’s health and economic effects. We focus instead on its political impact and its potential to exacerbate identity divisions, in particular. Psychologists argue that contagious disease increases threat perceptions and provokes policing of group boundaries. We explore how insider-outsider status and symptoms of illness shape perceptions of infection, reported willingness to help, and desire to restrict free movement of an ailing neighbor using a phone-based survey experiment administered three times in two neighboring African countries during different stages of the pandemic: Malawi, from May 5 to June 2, 2020 (n = 4,641); Zambia, from July 2 to August 13, 2020 (n = 2,198); and Malawi again, from March 9 to May 1, 2021 (n = 4,356). We study identities that are salient in Malawi and Zambia but have not induced significant prior violence, making our study a relatively hard test of disease threat theories. We find that symptoms more strongly shape perceptions and projected behavior than insider-outsider status in both countries and across time, suggesting that there are limits to the ability of pandemics to independently provoke identity politics de novo

Correlation measurements in high-multiplicity events

Requirements for correlation measurements in high--multiplicity events are discussed. Attention is focussed on detection of so--called hot spots, two--particle rapidity correlations, two--particle momentum correlations (for quantum interferometry) and higher--order correlations. The signal--to--noise ratio may become large in the high--multiplicity limit, allowing meaningful single--event measurements, only if the correlations are due to collective behavior.Comment: MN 55455, 20 pages, KSUCNR-011-92 and TPI-MINN-92/47-T (revised). Revised to correct typo in equation (30), and to fill in a few steps in calculations. Now published as Phys. Rev. C 47 (1993) 232

Indian patient use of cancer euphemisms: Association with psychological outcomes and health behaviours

Objective: Euphemisms may be used to reduce the threat associated with the word “cancer.” Cancer may be particularly threatening in Indian culture due to the myths surrounding its cause and prognosis. This study explored the prevalence of euphemism use by Indian patients and the relationship among euphemism use and illness cognitions, affect, health behaviour, and spontaneous self-affirmation (a behaviour associated with dealing with threat). Methods: In total, 350 cancer patients in India were recruited to take part in a study exploring patients' experiences of, and thoughts about, having an illness. They responded to a questionnaire measuring illness perceptions, coping strategies, anxiety, depression, health behaviours, and spontaneous self-affirmation. Patients were asked what words they used to describe their illness; euphemism users were those who used a euphemism (ie, non-medical term) as a first word. Results: About 51% of patients used a euphemism as a first word. Those with less education, unskilled employment, a lower income, and more children were more likely to be euphemism users. Euphemism users reported (a) weaker illness perceptions (less personal control, greater reporting of symptoms, and less understanding of their condition), (b) less use of 3 of 14 coping strategies, (c) less likelihood of spontaneously self-affirming, and (d) fewer healthy eating days. Conclusions: Euphemism use in patients was not related to distress but was related to negative illness perceptions and use of fewer coping strategies, suggesting that we need further study about the extent to which euphemisms signal issues in psychological adaptation to cancer diagnosis

Spin chirality on a two-dimensional frustrated lattice

The collective behavior of interacting magnetic moments can be strongly influenced by the topology of the underlying lattice. In geometrically frustrated spin systems, interesting chiral correlations may develop that are related to the spin arrangement on triangular plaquettes. We report a study of the spin chirality on a two-dimensional geometrically frustrated lattice. Our new chemical synthesis methods allow us to produce large single crystal samples of KFe3(OH)6(SO4)2, an ideal Kagome lattice antiferromagnet. Combined thermodynamic and neutron scattering measurements reveal that the phase transition to the ordered ground-state is unusual. At low temperatures, application of a magnetic field induces a transition between states with different non-trivial spin-textures.Comment: 7 pages, 4 figure

Reduction in the risk of human breast cancer by selective cyclooxygenase-2 (COX-2) inhibitors

BACKGROUND: Epidemiologic and laboratory investigations suggest that nonsteroidal anti-inflammatory drugs (NSAIDs) have chemopreventive effects against breast cancer due to their activity against cyclooxygenase-2 (COX-2), the rate-limiting enzyme of the prostaglandin cascade. METHODS: We conducted a case control study of breast cancer designed to compare effects of selective and non-selective COX-2 inhibitors. A total of 323 incident breast cancer patients were ascertained from the James Cancer Hospital, Columbus, Ohio, during 2003–2004 and compared with 649 cancer free controls matched to the cases at a 2:1 ratio on age, race, and county of residence. Data on the past and current use of prescription and over the counter medications and breast cancer risk factors were ascertained using a standardized risk factor questionnaire. Effects of COX-2 inhibiting agents were quantified by calculating odds ratios (OR) and 95% confidence intervals. RESULTS: Results showed significant risk reductions for selective COX-2 inhibitors as a group (OR = 0.29, 95% CI = 0.14–0.59), regular aspirin (OR = 0.49, 95% CI = 0.26–0.94), and ibuprofen or naproxen (0.36, 95% CI = 0.18–0.72). Acetaminophen, a compound with negligible COX-2 activity and low dose aspirin (81 mg) produced no significant change in the risk of breast cancer. CONCLUSION: Selective COX-2 inhibitors (celecoxib and rofecoxib) were only recently approved for use in 1999, and rofecoxib (Vioxx) was withdrawn from the marketplace in 2004. Nevertheless, even in the short window of exposure to these compounds, the selective COX-2 inhibitors produced a significant (71%) reduction in the risk of breast cancer, underscoring their strong potential for breast cancer chemoprevention

Development of a generic activities model of command and control

This paper reports on five different models of command and control. Four different models are reviewed: a process model, a contextual control model, a decision ladder model and a functional model. Further to this, command and control activities are analysed in three distinct domains: armed forces, emergency services and civilian services. From this analysis, taxonomies of command and control activities are developed that give rise to an activities model of command and control. This model will be used to guide further research into technological support of command and control activities