Freedom’s New Fight

Reviewing, Lawrence Lessig, Free Culture: How Big Media Uses Technology and the Law to Lock Down Culture and Control Creativity (2004

Portable appliance security apparatus

An apparatus for securing a small computer, or other portable appliance, against theft is described. It is comprised of a case having an open back through which the computer is installed or removed. Guide members in the form of slots are formed in a rear portion of opposite walls of the case for receiving a back plate to cover the opening and thereby secure the computer within the case. An opening formed in the top wall of the case exposes the keyboard and display of the computer. The back plate is locked in the closed position by a key-operated plug type lock. The lock is attached to one end of a hold down cable, the opposite end thereof being secured to a desk top or other stationary object. Thus, the lock simultaneously secures the back plate to the case and retains the case to the stationary object

Lock-In Agreements in Venture Capital Backed UK IPOs

This paper examines the impact of venture-capital backing of UK companies issuing shares at flotation on the characteristics of the lock-in agreements entered into by the existing shareholders, and on the abnormal returns realised around the expiry of the directors' lock-in agreements.The study examines the lock-in agreements of a sample of 186 UK IPOs issued during 1992-98. 103 of these companies had venture-capital backing at the IPO.The sample is also broken down into firms classified by industrial sector: of 103 VC backed companies 48 are high-tech, and among the 83 firms without VC backing 33 are high-tech.We find that lock-in agreements in the UK show much more variety in terms of the contractual detail than US agreements.Lock-in periods are particularly long for venture-backed high-tech companies.By contrast, for firms not in the high-tech sector, venture-capital backing appears to reduce the directors' lock-in periods.This suggests that for UK IPOs venture-capital backing does not serve as a substitute for lock-in agreements.Examining the proportion of locked-in directors' shares, we find it to be significantly higher in VC-backed firms as compared to firms without VC backing in the sample of firms not classified as high tech.This suggests that for firms likely to face only moderate information asymmetries (i.e. those not in high-tech industries), venture-capital backing of the IPO is not used as a substitute for, but rather as a complement to, lock-in agreements.The higher proportion of locked-in directors' shares among VC-backed companies (not in the high-tech sector) may be because the underwriters of VC-backed IPOs expect heavy sales by the VCs in the period after the IPO and decide to lock in the directors' shares and in order to limit the downward pressure of the VC's disposals on stock prices.Alternatively, if VCs do not sell out completely in the IPO, as reported by Barry et al. 1990, they may seek to align the directors' interests with their own by locking the directors in.We also examine the share-price performance of IPOs with and without VC backing around the time of the expiry of the lock-in agreements, and find that the CAARs for the VC-backed stocks are lower for most of the short windows around the expiry date, both for the sample as a whole and separately for each industry sector.For the sample of 28 VC-backed stocks, the CAARs are statistically significantly less than zero at the 1% level for the narrow one-to three-day windows around the expiry date.For the VC-backed stocks, the CAARs range from -1.2% to -1.6% (and even to -2% for the 11-day window, but this result is not statistically significant), while the corresponding CAARs for the stocks without VC backing range only from -0.2% to -0.8.initial public offerings;lock-in;high-tech;venture capital;IPO

Critique of a Hughes shuttle Ku-band data sampler/bit synchronizer

An alternative bit synchronizer proposed for shuttle was analyzed in a noise-free environment by considering the basic operation of the loop via timing diagrams and by linearizing the bit synchronizer as an equivalent, continuous, phased-lock loop (PLL). The loop is composed of a high-frequency phase-frequency detector which is capable of detecting both phase and frequency errors and is used to track the clock, and a bit transition detector which attempts to track the transitions of the data bits. It was determined that the basic approach was a good design which, with proper implementation of the accumulator, up/down counter and logic should provide accurate mid-bit sampling with symmetric bits. However, when bit asymmetry occurs, the bit synchronizer can lock up with a large timing error, yet be quasi-stable (timing will not change unless the clock and bit sequence drift). This will result in incorrectly detecting some bits

Heterogeneous and rate-dependent streptavidin-biotin unbinding revealed by high-speed force spectroscopy and atomistic simulations

Receptor-ligand interactions are essential for biological function and their binding strength is commonly explained in terms of static lock-and-key models based on molecular complementarity. However, detailed information of the full unbinding pathway is often lacking due, in part, to the static nature of atomic structures and ensemble averaging inherent to bulk biophysics approaches. Here we combine molecular dynamics and high-speed force spectroscopy on the streptavidin-biotin complex to determine the binding strength and unbinding pathways over the widest dynamic range. Experiment and simulation show excellent agreement at overlapping velocities and provided evidence of the unbinding mechanisms. During unbinding, biotin crosses multiple energy barriers and visits various intermediate states far from the binding pocket while streptavidin undergoes transient induced fits, all varying with loading rate. This multistate process slows down the transition to the unbound state and favors rebinding, thus explaining the long lifetime of the complex. We provide an atomistic, dynamic picture of the unbinding process, replacing a simple two-state picture with one that involves many routes to the lock and rate-dependent induced-fit motions for intermediates, which might be relevant for other receptor-ligand bonds.Comment: 21 pages, 4 figure

Neutron diffraction study of stripe order in La(2)NiO(4+d) with d=2/15

We report a detailed neutron scattering study of the ordering of spins and holes in oxygen-doped La(2)NiO(4.133). The single-crystal sample exhibits the same oxygen-interstitial order but better defined charge-stripe order than that studied previously in crystals with d = 0.125. In particular, charge order is observed up to a temperature at least twice that of the magnetic transition, T_m = 110.5 K. On cooling through T_m, the wave vector \epsilon, equal to half the charge-stripe density within an NiO(2) layer, jumps discontinuously from 1/3 to 0.2944. It continues to decrease with further cooling, showing several lock-in transitions on the way down to low temperature. To explain the observed lock-ins, a model is proposed in which each charge stripe is centered on either a row of Ni or a row of O ions. The model is shown to be consistent with the l-dependence of the magnetic peak intensities and with the relative intensities of the higher-order magnetic satellites. Analysis of the latter also provides evidence that the magnetic domain walls (charge stripes) are relatively narrow. In combination with a recent study of magnetic-field-induced effects, we find that the charge stripes are all O-centered at T>T_m, with a shift towards Ni centering at T<T_m. Inferences concerning the competing interactions responsible for the the temperature dependence of \epsilon and the localization of charge within the stripes are discussed.Comment: ReVTeX, 17 2-col pages, 10 eps figs. embedded with psfig, submitted to Phys. Rev.

A Template for Implementing Fast Lock-free Trees Using HTM

Algorithms that use hardware transactional memory (HTM) must provide a software-only fallback path to guarantee progress. The design of the fallback path can have a profound impact on performance. If the fallback path is allowed to run concurrently with hardware transactions, then hardware transactions must be instrumented, adding significant overhead. Otherwise, hardware transactions must wait for any processes on the fallback path, causing concurrency bottlenecks, or move to the fallback path. We introduce an approach that combines the best of both worlds. The key idea is to use three execution paths: an HTM fast path, an HTM middle path, and a software fallback path, such that the middle path can run concurrently with each of the other two. The fast path and fallback path do not run concurrently, so the fast path incurs no instrumentation overhead. Furthermore, fast path transactions can move to the middle path instead of waiting or moving to the software path. We demonstrate our approach by producing an accelerated version of the tree update template of Brown et al., which can be used to implement fast lock-free data structures based on down-trees. We used the accelerated template to implement two lock-free trees: a binary search tree (BST), and an (a,b)-tree (a generalization of a B-tree). Experiments show that, with 72 concurrent processes, our accelerated (a,b)-tree performs between 4.0x and 4.2x as many operations per second as an implementation obtained using the original tree update template