A quotient of the Lubin-Tate tower

In this article we show that the quotient of the Lubin-Tate space at infinite level by the Borel subgroup of upper triangular matrices in GL(2,Q_p) exists as a perfectoid space. As an application we show that Scholze's functor H^i_et(P^1,F(pi)) is concentrated in degree one whenever pi is a principal series representation or a twist of the Steinberg representation of GL(2,Q_p).Comment: to appear in Forum of Mathematics, Sigma. 33 page

Adult mesenchymal stem cell therapy for myelin repair in Multiple Sclerosis.

Multiple sclerosis (MS) is a demyelinating immune-mediated disease of the central nervous system (CNS). It is the most frequent neurological disease in young adults and affects over 2 million people worldwide. Current treatments reduce the relapse rate and the formation of inflammatory lesions in the CNS, but with only temporary and limited success. Despite the presence of endogenous oligodendroglial progenitors (OPCs) and of spontaneous remyelination, at least in early MS its levels and its qualities are apparently insufficient for a sustained endogenous functional repair. Therefore, novel MS therapies should consider not only immunemodulatory but also myelin repair activities. Mesenchymal stem cells (MSCs) represent an attractive alternative to develop a cell-based therapy for MS. MSCs display stromal features and exert bystander immunemodulatory and neuroprotective activities. Importantly, MSCs induce oligodendrocyte fate decision and differentiation/maturation of adult neural progenitors, suggesting the existence of MSC-derived remyelination activity. Moreover, transplanted MSCs promote functional recovery and myelin repair in different MS animal models. Here, we summarize the current knowledge on endogenous mechanisms for remyelination and proposed autologous MSC therapy as a promising strategy for MS treatment

NetzCope: A Tool for Displaying and Analyzing Complex Networks

Networks are a natural and popular mechanism for the representation and investigation of a broad class of systems. But extracting information from a network can present significant challenges. We present NetzCope, a software application for the display and analysis of networks. Its key features include the visualization of networks in two or three dimensions, the organization of vertices to reveal structural similarity, and the detection and visualization of network communities by modularity maximization.Comment: 16 pages, Proceedings of ICQBIC2010; minor improvements to wording in v

The Effects of Gun Prevalence on Burglary: Deterrence vs Inducement

The proposition that widespread gun ownership serves as a deterrent to residential burglary is widely touted by advocates, but the evidence is weak, consisting of anecdotes, interviews with burglars, casual comparisons with other countries, and the like. A more systematic exploration requires data on local rates of gun ownership and of residential burglary, and such data have only recently become available. In this paper we exploit a new well-validated proxy for local gun-ownership prevalence -- the proportion of suicides that involve firearms -- together with newly available geo-coded data from the National Crime Victimization Survey, to produce the first systematic estimates of the net effects of gun prevalence on residential burglary patterns. The importance of such empirical work stems in part from the fact that theoretical considerations do not provide much guidance in predicting the net effects of widespread gun ownership. Guns in the home may pose a threat to burglars, but also serve as an inducement, since guns are particularly valuable loot. Other things equal, a gun-rich community provides more lucrative burglary opportunities than one where guns are more sparse. The new empirical results reported here provide no support for a net deterrent effect from widespread gun ownership. Rather, our analysis concludes that residential burglary rates tend to increase with community gun prevalence.

The Social Costs of Gun Ownership

This paper provides new estimates of the effect of household gun prevalence on homicide rates, and infers the marginal external cost of handgun ownership. The estimates utilize a superior proxy for gun prevalence, the percentage of suicides committed with a gun, which we validate. Using county- and state-level panels for 20 years, we estimate the elasticity of homicide with respect to gun prevalence as between +.1 and +.3. All of the effect of gun prevalence is on gun homicide rates. Under certain reasonable assumptions, the average annual marginal social cost of household gun ownership is in the range $100 to$600.

Assigning Deviant Youths to Minimize Total Harm

A common practice in the fields of education, mental health, and juvenile justice is to segregate problem youths in groups with deviant peers. Assignments of this sort, which concentrate deviant youths, may facilitate deviant peer influence and lead to perverse outcomes. This possibility adds to the list of arguments in support of "mainstreaming" whenever possible. But there are other concerns that help justify segregated-group assignments, including efficiency of service delivery and protection of the public. Our analysis organizes the discussion about the relevant tradeoffs. First, the number of deviant youths (relative to the size of the relevant population, or to the number of assignment locations) affects whether the harm-minimizing assignment calls for diffusion or segregation. Second, the nature of the problematic behavior is relevant; behavior which has a direct, detrimental effect on others who share the assignment makes a stronger case for segregation. Third, the capacity for behavior control matters, and may make the difference in a choice between segregation and integration. We briefly discuss the empirical literature, which with some exceptions is inadequate to the task of providing clear guidance about harm-minimizing assignment strategies. Finally, we reflect briefly on the medical-practice principle "first do no harm," and contrast it with the claims of potential victims of deviants.