Untitled: A Study of Formal and Informal Property Rights in Urban Ecuador

In this paper we explore the substitutability of formal and informal property rights. We analyze new survey data from Ecuador, where households have both formal and informal claims to urban residential property. The latter come from a variety of sources, including the activity of a local boss, or organizer. We first develop a theory of the ability to sell or rent land in which a distinction is drawn between transferable property rights (e.g., title) and non-transferable claims (e.g., length of residence). We use this theory of transactions to show that the increase in price that follows the granting of title may be an overestimate of the households' utility gain. In our empirical work we find that the unconditional effect of granting title is to raise properties' value by 23.5%. However, we also find that informal property rights can substitute effectively for formal property rights, so the marginal effect of titling on the ability to transact and on prices can vary widely among communities and among households within a community. For example, the value of property owned by a newly established household with no adult males can increase by 46% with the acquisition of title. These findings suggest that titling programs should be targeted at young disorganized communities if they are to have much effect.

An ion resonance instability in grossly non-neutral plasmas

Ion resonance instability in grossly non-neutral plasma

Electrical manipulation of an electronic two-state system in Ge/Si quantum dots

We calculate that the electron states of strained self-assembled Ge/Si quantum dots provide a convenient two-state system for electrical control. An electronic state localized at the apex of the quantum dot is nearly degenerate with a state localized at the base of the quantum dot. Small electric fields shift the electronic ground state from apex-localized to base-localized, which permits sensitive tuning of the electronic, optical and magnetic properties of the dot. As one example, we describe how spin-spin coupling between two Ge/Si dots can be controlled very sensitively by shifting the individual dot's electronic ground state between apex and base

Fast Matrix Factorization for Online Recommendation with Implicit Feedback

This paper contributes improvements on both the effectiveness and efficiency of Matrix Factorization (MF) methods for implicit feedback. We highlight two critical issues of existing works. First, due to the large space of unobserved feedback, most existing works resort to assign a uniform weight to the missing data to reduce computational complexity. However, such a uniform assumption is invalid in real-world settings. Second, most methods are also designed in an offline setting and fail to keep up with the dynamic nature of online data. We address the above two issues in learning MF models from implicit feedback. We first propose to weight the missing data based on item popularity, which is more effective and flexible than the uniform-weight assumption. However, such a non-uniform weighting poses efficiency challenge in learning the model. To address this, we specifically design a new learning algorithm based on the element-wise Alternating Least Squares (eALS) technique, for efficiently optimizing a MF model with variably-weighted missing data. We exploit this efficiency to then seamlessly devise an incremental update strategy that instantly refreshes a MF model given new feedback. Through comprehensive experiments on two public datasets in both offline and online protocols, we show that our eALS method consistently outperforms state-of-the-art implicit MF methods. Our implementation is available at https://github.com/hexiangnan/sigir16-eals.Comment: 10 pages, 8 figure

A comparison of cognitive restructuring and thought listing for excessive acquiring in hoarding disorder

Excessive acquiring is a common symptom of hoarding disorder (HD). Little is known about subjective distress associated with acquiring in HD. The present study examined acquiring- related distress and reactions to cognitive restructuring (CR) in 92 individuals with HD and 66 community control (CC) participants. All participants identified an item of interest at a high-risk acquiring location and then decided whether or not to acquire the item. HD participants completed the acquiring task while receiving a CR-based intervention or a thought-listing (TL) control condition. Results showed that HD participants reported more severe distress and greater urges to acquire the item of interest than did CC participants. Nevertheless, subjective distress decreased in both groups following the acquiring task. There were no differences in acquiring- related distress between the CR and TL conditions. The findings indicate that subjective distress may decrease after relatively short periods of time in individuals with HD, but that a single session of CR may not alleviate acquiring-related distress in HD participants.R01 MH068007 - NIMH NIH HHS; R01 MH068008 - NIMH NIH HHSAccepted manuscrip

A Difficult Question in Deed: A Cost-Benefit Framework for Titling Programs

In this Article we explore the potential benefits and costs of a program to grant title to individuals who are occupying land informally. Only some of these benefits and costs have received careful empirical consideration in the literature. This Article references existing studies and draws on findings from original surveys of urban households in Ecuador. We consider how a titling program might affect the welfare of landowners and occupants, how it could alter the functioning of real estate markets, and whether it could build a community\u27s social capital. Potential benefits must be weighed against a range of costs, including those accruing to the government for implementation of the program, as well as those perceived by individuals in their efforts to obtain title. There also may be dynamic implications of a titling program. For example, these programs can spur further land invasions and render the role of intermediaries more lucrative. The importance of formal property rights and of formal legal systems in governing transactions and land use is of particular interest given that property rights are frequently assigned the prominent role of a prerequisite to economic growth

Neutron capture production rates of cosmogenic 60Co, 59Ni and 36Cl in stony meteorites

Results for neutron flux calculations in stony meteoroids (of various radii and compositions) and production rates for Cl-36, Ni-59, and Co-60 are reported. The Ni-59/Co-60 ratio is nearly constant with depth in most meteorites: this effect is consistent with the neutron flux and capture cross section properties. The shape of the neutron flux energy spectrum, varies little with depth in a meteorite. The size of the parent meteorite can be determined from one of its fragments, using the Ni-59/Co-60 ratios, if the parent meteorite was less than 75 g/cm(2) in radius. If the parent meteorite was larger, a lower limit on the size of the parent meteorite can be determined from a fragment. In C3 chondrites this is not possible. In stony meteorites with R less than 50 g/cm(2) the calculated Co-60 production rates (mass less than 4 kg), are below 1 atom/min g-Co. The highest Co-60 production rates occur in stony meteorites with radius about 250 g/cm(2) (1.4 m across). In meteorites with radii greater than 400 g/cm(2), the maximum Co-60 production rate occurs at a depth of about 175 g/cm(2) in L-chondrite, 125 g/cm(2) in C3 chrondrite, and 190 g/cm(2) in aubrites