Why are Male IQ Scores More Variable?

The male female difference in the variance of quantitative traits including IQ can be accounted for by the observation of the concentration of genes involved in brain development on the X chromosome and by the mechanism of sex determination in mammals. Females have two X chromosomes with one randomly inactivated. Males have a single X chromosome, which results in increased variance. It is shown that these factors are sufficient to account for the observed differences

User-Relative Names for Globally Connected Personal Devices

Nontechnical users who own increasingly ubiquitous network-enabled personal devices such as laptops, digital cameras, and smart phones need a simple, intuitive, and secure way to share information and services between their devices. User Information Architecture, or UIA, is a novel naming and peer-to-peer connectivity architecture addressing this need. Users assign UIA names by "introducing" devices to each other on a common local-area network, but these names remain securely bound to their target as devices migrate. Multiple devices owned by the same user, once introduced, automatically merge their namespaces to form a distributed "personal cluster" that the owner can access or modify from any of his devices. Instead of requiring users to allocate globally unique names from a central authority, UIA enables users to assign their own "user-relative" names both to their own devices and to other users. With UIA, for example, Alice can always access her iPod from any of her own personal devices at any location via the name "ipod", and her friend Bob can access her iPod via a relative name like "ipod.Alice".Comment: 7 pages, 1 figure, 1 tabl

Entropy measures as geometrical tools in the study of cosmology

Classical chaos is often characterized as exponential divergence of nearby trajectories. In many interesting cases these trajectories can be identified with geodesic curves. We define here the entropy by $S = \ln \chi (x)$ with $\chi(x)$ being the distance between two nearby geodesics. We derive an equation for the entropy which by transformation to a Ricatti-type equation becomes similar to the Jacobi equation. We further show that the geodesic equation for a null geodesic in a double warped space time leads to the same entropy equation. By applying a Robertson-Walker metric for a flat three-dimensional Euclidian space expanding as a function of time, we again reach the entropy equation stressing the connection between the chosen entropy measure and time. We finally turn to the Raychaudhuri equation for expansion, which also is a Ricatti equation similar to the transformed entropy equation. Those Ricatti-type equations have solutions of the same form as the Jacobi equation. The Raychaudhuri equation can be transformed to a harmonic oscillator equation, and it has been shown that the geodesic deviation equation of Jacobi is essentially equivalent to that of a harmonic oscillator. The Raychaudhuri equations are strong geometrical tools in the study of General Relativity and Cosmology. We suggest a refined entropy measure applicable in Cosmology and defined by the average deviation of the geodesics in a congruence.Comment: Final Versio

Improving network connection locality on multicore systems

Incoming and outgoing processing for a given TCP connection often execute on different cores: an incoming packet is typically processed on the core that receives the interrupt, while outgoing data processing occurs on the core running the relevant user code. As a result, accesses to read/write connection state (such as TCP control blocks) often involve cache invalidations and data movement between cores' caches. These can take hundreds of processor cycles, enough to significantly reduce performance. We present a new design, called Affinity-Accept, that causes all processing for a given TCP connection to occur on the same core. Affinity-Accept arranges for the network interface to determine the core on which application processing for each new connection occurs, in a lightweight way; it adjusts the card's choices only in response to imbalances in CPU scheduling. Measurements show that for the Apache web server serving static files on a 48-core AMD system, Affinity-Accept reduces time spent in the TCP stack by 30% and improves overall throughput by 24%.National Science Foundation (U.S.). (Grant number CNS-0834415)National Science Foundation (U.S.). (Grant number CNS-0915164)Quanta Computer (Firm

Device-transparent personal storage

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2010.Cataloged from PDF version of thesis.Includes bibliographical references (p. 83-87).Users increasingly store data collections such as digital photographs on multiple personal devices, each of which typically presents the user with a storage management interface isolated from the contents of all other devices. The result is that collections easily become disorganized and drift out of sync. This thesis presents Eyo, a novel personal storage system that provides device transparency: a user can think in terms of "file X", rather than "file X on device Y", and will see the same set of files on all personal devices. Eyo allows a user to view and manage the entire collection of objects from any of their devices, even from disconnected devices and devices with too little storage to hold all the object content. Eyo separates metadata (application-specific attributes of objects) from the content of objects, allowing even storage-limited devices to store all metadata and thus provide device transparency. Fully replicated metadata allows any set of Eyo devices to efficiently synchronize updates. Applications can specify flexible placement rules to guide Eyo's partial replication of object contents across devices. Eyo's application interface provides first-class access to object version history. If multiple disconnected devices update an object concurrently, Eyo preserves each resulting divergent version of that object. Applications can then examine the history and either coalesce the conflicting versions without user direction, or incorporate these versions naturally into their existing user interfaces. Experiments using Eyo for storage in several example applications-media players, a photo editor, podcast manager, and an email interface-show that device transparency can be had with minor application changes, and within the storage and bandwidth capabilities of typical portable devices.by Jacob Alo Strauss.Ph.D

Backbone NMR resonance assignment of the Abelson kinase domain in complex with imatinib

Imatinib (Glivec or Gleevec) potently inhibits the tyrosine kinase activity of BCR-ABL, a constitutively activated kinase, which causes chronic myelogenous leukemia (CML). Here we report the first almost complete backbone assignment of c-ABL kinase domain in complex with imatini

Costing analysis of an SMS-based intervention to promote HIV self-testing amongst truckers and sex workers in Kenya

Objective HIV testing rates in many sub-Saharan African countries have remained suboptimal, and there is an urgent need to explore strategic yet cost-effective approaches to increase the uptake of HIV testing, especially among high-risk populations. Methods A costing analysis was conducted for a randomized controlled trial (RCT) with male truckers and female sex workers (FSWs) registered in the electronic health record system (EHRS) of the North Star Alliance, which offers healthcare services at major transit hubs in Southern and East Africa. The RCT selected a sample of truckers and FSWs who were irregular HIV testers, according to the EHRS, and evaluated the effect of SMSs promoting the availability of HIV self-testing (HIVST) kits in Kenyan clinics (intervention program) versus a general SMS reminding clients to test for HIV (enhanced and standard program) on HIV testing rates. In this paper, we calculated costs from a provider perspective using a mixed-methods approach to identify, measure, and value the resources utilized within the intervention and standard programs. The results of the analysis reflect the cost per client tested. Results The cost of offering HIVST was calculated to be double that of routine facility-based testing (USD 10.13 versus USD 5.01 per client tested), primarily due to the high price of the self-test kit. In the two study arms that only offered provider-administered HIV testing in the clinic, only 1% of truckers and 6% of FSWs tested during the study period, while in the intervention arm, which also offered HST, approximately 4% of truckers and 11% of FSWs tested. These lower than expected outcomes resulted in relatively high cost per client estimates for all three study arms. Within the intervention arm, 65% of truckers and 72% of FSWs who tested chose the HIVST option. However, within the intervention arm, the cost per additional client tested was lower for FSWs than for truckers, at USD 0.15 per additional client tested versus USD 0.58 per additional client tested, driven primarily by the higher response rates. Conclusion Whilst the availability of HIVST increased HIV testing among both truckers and FSWs, the cost of providing HIVST is higher than that of a routine health facility-based test, driven primarily by the price of the HIV self-test kit. Future research needs to identify strategies which increase demand for HIVST, and determine whether these strategies and the subsequent increased demand for HIVST are cost-effective in relation to the conventional facility based testing currently available