Exponential lower bounds for depth three Boolean circuits

We consider the class of unbounded fan-in depth three Boolean circuits, for which the bottom fan-in is limited by k and the top gate is an OR. It is known that the smallest such circuit computing the parity function has gates (for k = O(n ^1/2)) for some , and this was the best lower bound known for explicit (P-time computable) functions. In this paper, for k = 2, we exhibit functions in uniform NC ¹ that require size depth 3 circuits. The main tool is a theorem that shows that any circuit on n variables that accepts a inputs and has size s must be constant on a projection (subset defined by equations of the form x _i = 0, x _i = 1, x _i = x _j or x _i = ) of dimension at least log(a/s)log n. Received: April 1, 1997.     

Lower Bounds on the Randomized Communication Complexity of Read-Once Functions

We prove lower bounds on the randomized two-party communication complexity of functions that arise from read-once boolean formulae. A read-once boolean formula is a formula in propositional logic with the property that every variable appears exactly once. Such a formula can be represented by a tree, where the leaves correspond to variables, and the internal nodes are labeled by binary connectives. Under certain assumptions, this representation is unique. Thus, one can define the depth of a formula as the depth of the tree that represents it. The complexity of the evaluation of general read-once formulae has attracted interest mainly in the decision tree model. In the communication complexity model many interesting results deal with specific read-once formulae, such as DISJOINTNESS and TRIBES. In this paper we use information theory methods to prove lower bounds that hold for any read-once formula. Our lower bounds are of the form n(f)/c^d(f), where n(f) is the number of variables and d(f) is the depth of the formula, and they are optimal up to the constant in the base of the denominator.     

Chronic exposure of rats to hypoxic environment alters the mechanism of energy transfer in myocardium

We have investigated the effect of chronic exposure of rats to an hypoxic environment (10% O2; 3 weeks), on the first step of the intracellular energy transfer process in the myocardium, i.e. the transfer at mitochondrial level of high energy bonds from ATP to creatine. In the left ventricles from rats adapted to normobaric hypoxia, we observed, using the permeabilized fiber technique, that the stimulatory effect of creatine on the mitochondrial respiration in presence of a low ADP concentration (0.1 mM) was attenuated when compared to control. Furthermore, the creatine-induced decrease of the apparent K(m) for ADP of the mitochondrial respiration, which is observed in control, was significantly reduced. Both the basal and maximal respiratory rates of the fibers were unchanged by the hypoxic exposure of the rats. A significant decrease of the total creatine kinase activity from 755 to 630 IU/g wet weight (for control and hypoxic rats, respectively) was detected and was accompanied by a 25% decrease in mitochondrial isoform activity (mitoCK) and in the mitoCK/citrate synthase ratio. In the right ventricles, identical alterations in the effect of creatine on apparent K(m) for ADP were observed while we did not detect any changes in CK activity. The decrease in mitoCK activity and the fall in the reactivity of respiration to creatine could be interpreted as a mechanism for downregulating oxygen demand during chronic hypoxia. The consequences of such alterations on energy metabolism of cardiomyocytes under conditions of reduced oxygen supply are discussed.     

Determination of interface trap capture cross sections usingthree-level charge pumping

A modified three-voltage-level charge pumping (CP) technique is described for measuring interface trap parameters in MOSFETs. Charge pumping (CP) is a technique for studying traps at the Si-SiO₂ interface in MOS transistors. In the CP technique, a pulse is applied to the gate of the MOSFET which alternately fills the traps with electrons and holes, thereby causing a recombination current I_cp to flow in the substrate. With this technique, interface trap capture cross sections for both electrons and holes may be determined as a function of trap energy in a single device. It is demonstrated that a modified three-level charge pumping method may be used to determine not only interface trap densities but also to capture cross sections as a function of trap energy. The trap parameters are obtained for both electrons and holes using a single MOSFET     

Effects of hydrogen annealing on MOS oxides

The effects of annealing MOS oxides at high temperatures in hydrogen or deuterium have been studied. Annealing at temperatures above ≈800° C causes a dramatic increase in the radiation sensitivity of the oxide. High temperature annealing also appears to cause a decrease in the dielectric strength of the oxide. Secondary ion mass spectrometry (SIMS) profiles of deuterium-annealed oxides reveal a substantial uptake of deuterium during the annealing. These results suggest that exposure of gate oxides to hydrogen at high temperatures should be avoided.     

A census of subject pool characteristics and policies.

A census of the 366 psychology departments that have subject pools and graduate programs yielded an 89% response rate. Of the 74% that reported having a subject pool, 93% recruit from introductory courses. An experiment within the survey indicated that respondents were generally candid. Many departments were found to be not entirely in conformance with American Psychological Association (APA) ethical guidelines or federal law: For example, subject pools that offer no clear educational benefit and have only unattractive alternatives to participation are actually nonvoluntary. Some departments evinced (a) exemplary procedures for making participation an educational experience; (b) readable subject pool announcements that had clear rules, were not coercive, and were respectful in tone and content; or (c) subject pool administration that provided accurate record keeping, appropriate channels of ethical review, and responsiveness to student concerns, questions, and complaints. These procedures, which deserve emulation by other departments, are summarized, and copies of the actual departmental documents are available from the National Auxiliary Publication Service. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Time dependence of interface trap formation in MOSFETs followingpulsed irradiation

The time dependence of interference trap (N_it) formation in MOSFETs was studied as a function of gate oxide thickness, oxide growth type, substrate orientation, temperature, and gate bias. Two different N_it formation mechanisms are observed. Most (typically 90%) of the formation, called the late process, occurs slowly at long times (1-10000 s) after the radiation pulse. From a variety of experimental data, it is concluded that the rate of the late process is limited by drift of a radiation-induced positive ion, probably H⁺ , through the gate oxide to the Si-SiO₂ interface where the N_it are formed. A relatively fast, or early, process is responsible for a small percentage of the total N_it formation. The time constant for this process appears to be consistent with hole drift through the oxide     

Social psychological contributions to a legislative subcommittee on organ and tissue transplants.

Considers the role of the psychologist in public policymaking. The specific medico-legal issues related to organ and tissue transplants from minor donors are reviewed, along with the background of a subcommittee of the Massachusetts Special Legislative Commission Concerning Human Clinical Investigation and Experimental Therapy. Substantive social psychological contributions to the subcommittee are reported. The psycholgist's role in public policy is reconsidered; emphasis is placed on the need for (a) training in the application of basic-research knowledge to social problems, and (b) preparation for assuming more active policymaking roles. (2 p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Determination of critical velocity of suspension flow

Suspension of solid particles in air flow is considered and flow critical velocity is determined. A comparison is made of computational and experimental results.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 18, No. 5, pp. 832–837, May, 1970.