Effect of Surface Roughness on the Acid Etching of Amorphous Silica

The effect of the root-mean-square (rms) roughness on the acid etching of roughened amorphous silica was studied as a function of time using atomic force microscopy and laser light scattering. The initial size and distribution of micrometer-sized surface flaws are shown to influence the time evolution of the etching by hydrofluoric acid. The increase in the optical transparency of the samples is linked to the large increases in the correlation lengths of the sample surfaces, an effect which counteracts the accompanying rise in the rms roughness.     

Towards a re-programmable DNA computer

Microreactors lend themselves to a relatively simple implementation of DNA computing. Not only is the design of the DNA library critical for the success of the system but also the architecture of the microfluidic structure. Microreactors can be configured as Boolean operators. This paper will show that biomolecular computing can be performed with elementary building blocks, analogous to electronic logic gates. These logical operations will be performed using negative selection. Furthermore, an alternative bead barrier is introduced which can render the computer re-programmable and shows an principle architecture for selection and analysis.     

Best Linear Unbiased Estimator of the Parameter of the Rayleigh Distribution?Part II: Optimum Theory for Selected Order Statistics

The member of the class of best linear unbiased estimators (BLUEs) of a parameter based on k order statistics which has minimum variance is called the k-optimum BLUE. The ranks, coefficients, variance, and efficiency are given for the k-optimum BLUE of the parameter of the Rayleigh distribution for k = 2(1)4 and a sample size of N = 2(1)22. In addition, an approximate k-optimum BLUE is given for k = 2(1)4 and N ? 23.     

Prospective study of postpartum depression: Prevalence, course, and predictive factors.

[Correction Notice: An erratum for this article was reported in Vol 94(2) of Journal of Abnormal Psychology (see record 2008-10964-001). Much of the data reported in Tables 4 and 5 are incorrect. Most of the errors are small and they do not affect the p values shown in the tables, with three exceptions which are provided in the erratum.] 99 women (mean age 26.5 yrs) were followed from the 2nd trimester of pregnancy until about 6 mo postpartum. Depression diagnostic and severity assessments were conducted during pregnancy and after delivery. Instruments included the Beck Depression Inventory and an interview adapted from the Schedule of Affective Disorders and Schizophrenia. Depression severity decreased steadily from the 2nd trimester until 9 wks postpartum. Approximately 9% of the Ss during pregnancy and 12% of the Ss during the postpartum period were diagnosed as having a major or minor depression. A model of depression was constructed to account for both postpartum depression symptomatology and the syndrome of postpartum depression. Predictor variables (e.g., prepartum depression symptomatology, obstetric risk factors) accounted for about 50% of the variance in depressive symptomatology. Predictor variables (e.g., depression history, stressful childcare events) accounted for about 30% of the variance in diagnostic status. Findings underscore the importance of studying changes in depression diagnostic status as well as changes in level of depressive symptomatology in prospective studies. (43 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Joint Rate-and-Power Allocation for Multi-channel Spectrum Sharing Networks with Balanced QoS Provisioning and Power Saving

In this paper we study the joint rate-and-power allocation for multi-channel spectrum sharing networks with balanced QoS provisioning and power saving. We formulate this cross-layer optimization problem as a non-cooperative game G _JRPA in which each user has a coupled two-tuple strategy, i.e., simultaneous rate and multi-channel power allocations. A multi-objective cost function is proposed to represent user’s awareness of both QoS provisioning and power saving. We analyze the properties of Nash equilibrium (N.E.) for our G _JRPA , including its existence, and properties of QoS provisioning and power saving. Furthermore, we derive a layered structure by applying the Lagrangian dual decomposition to G _JRPA and design a distributed algorithm to find the N.E.. Simulation results are presented to show the validity of our game theoretic formulation and the performance of our proposed algorithm. Detailed studies on the performance tradeoff between QoS provisioning and power saving are also carried out.

Very low energy homes in the United States: Perspectives on performance from measured data

We present measured annual performance data from a dozen recent-vintage very low energy homes in North America. Many of the designs combine greater energy efficiency with solar electric photovoltaic power in an attempt to create Zero Energy Homes (ZEH). We also provide measured data from the first home constructed to the German Passivhaus standard in the United States. Several projects either exceeded or come very close to true net zero energy when evaluated over a year.The data indicate that very low energy use buildings can very readily be achieved in North America. Annual energy use half that or less than standard housing can be achieved for an equivalent cost of $0.10/kWh from the efficiency investment. In general, the better cost effectiveness seen from energy efficiency measures indicates that greater investment in conservation should be a prerequisite to installation of solar water heating and solar electricity in Zero Energy Homes. However, over emphasis in efficiency is also possible. This suggests that optimization tools such as BEopt and EGUSA, which characterize both renewable resource performance and that also of specific combinations of energy efficiency measures, will best guide designers to locate the most economically favorable mix to reach an energy neutral level.     

Completeness in Two-Party Secure Computation: A Computational View

A Secure Function Evaluation (SFE) of a two-variable function f(·,·) is a protocol that allows two parties with inputs x and y to evaluate f(x,y) in a manner where neither party learns "more than is necessary". A rich body of work deals with the study of completeness for secure two-party computation. A function f is complete for SFE if a protocol for securely evaluating f allows the secure evaluation of all (efficiently computable) functions. The questions investigated are which functions are complete for SFE, which functions have SFE protocols unconditionally and whether there are functions that are neither complete nor have efficient SFE protocols. The previous study of these questions was mainly conducted from an information theoretic point of view and provided strong answers in the form of combinatorial properties. However, we show that there are major differences between the information theoretic and computational settings. In particular, we show functions that are considered as having SFE unconditionally by the combinatorial criteria but are actually complete in the computational setting. We initiate the fully computational study of these fundamental questions. Somewhat surprisingly, we manage to provide an almost full characterization of the complete functions in this model as well. More precisely, we present a computational criterion (called computational row non-transitivity) for a function f to be complete for the asymmetric case. Furthermore, we show a matching criterion called computational row transitivity for f to have a simple SFE (based on no additional assumptions). This criterion is close to the negation of the computational row non-transitivity and thus we essentially characterize all "nice" functions as either complete or having SFE unconditionally.     

Comparison of arterial transit times estimated using arterial spin labeling

Objective  

To compare arterial transit time estimates from two efficient transit time mapping techniques using arterial spin labeling (ASL)—flow encoded arterial spin tagging (FEAST) and Look-Locker ASL (LL-ASL). The effects of bipolar gradients and label location were investigated.