On-Line Instruction-checking in Pipelined Microprocessors

Microprocessors performances have increased by more than five orders of magnitude in the last three decades. As technology scales down, these components become inherently unreliable posing major design and test challenges. This paper proposes an instruction-checking architecture to detect erroneous instruction executions caused by both permanent and transient errors in the internal logic of a microprocessor. Monitoring the correct activation sequence of a set of predefined microprocessor control/status signals allow distinguishing between correctly and not correctly executed instruction

Critical Behavior of CP^1 at theta = pi, Haldane's Conjecture and the Universality Class

Using an approach to analyze the theta dependence of systems with a theta-term we recently proposed, the critical behavior of CP^1 at theta=pi is studied. We find a region outside the strong coupling regime where Haldane's conjecture is verified. The critical line however does not belong to the universality class of the Wess-Zumino-Novikov-Witten model at topological coupling k=1 since it shows continuously varying critical exponents.Comment: 4 pages, 5 figure

Renormalization group and triviality in noncompact lattice QED with light fermions

In the framework of noncompact lattice QED with light fermions, we derive the functional dependence of the average energy per plaquette on the bare parameters using block-spin Renormalization Group arguments and assuming that the renormalized coupling vanishes. Our numerical results for this quantity in $8^4$ and $10^4$ lattices show evidence for triviality in the weak coupling phase and point to a non vanishing value for the renormalized coupling constant in the strong coupling phase.Comment: 9 page

Obstructive sleep apnea syndrome in the pediatric age: the role of the dentist

Sleep disordered breathing in children designates a wide spectrum of respiratory disorders characterized by partial or complete obstruction of the upper airways. It ranges from primary snoring, its mildest clinical manifestation, to obstructive sleep apnea syndrome (OSAS): complete obstruction of the upper airways with cessation of airflow. The aim of this paper is to highlight the roles of the pediatric dentist and the orthodontist in the therapeutic approach to pediatric OSAS as a "sentinel" who can detect early signs of the disease for immediate referral to the otolaryngologist and as an active participant in therapy

Monolithic zirconia and digital impression: case report

The aim of this study is to present a clinical case of a full arch prosthetic rehabilitation on natural teeth, combining both digital work-flow and monolithic zirconi

Salivary bacterial leakage into implant-abutment connections: preliminary results of an in vitro study

OBJECTIVE: The occurrence of bacterial leakage in the internal surface of implants, through implant-abutment interface (IAI), is one of the parameters for analyzing the fabrication quality of the connections. The aim of this in vitro study is to evaluate two different types of implant-abutment connections: the screwed connection (Group 1) and the cemented connection (Group 2), analyzing the permeability of the IAI to bacterial colonization, using human saliva as culture medium. PATIENTS AND METHODS: A total of twelve implants were tested, six in each experimental group. Five healthy patients were enrolled in this study. Two milliliters of non-stimulated saliva were collected from each subject and mixed in a test tube. After 14 days of incubation of the bacteria sample in the implant fixtures, a PCR-Real Time analysis was performed. Fisher's exact test was used to compare the proportions of implant-abutment assembled structures detected with bacterial leakage. Differences in the bacterial counts of the two groups were compared using the Mann-Whitney U test. A p value < 0.05 was considered significant. RESULTS: The results showed a decreased stability with the screwed implant-abutment connections compared to the cemented implant-abutment connections. A mean total bacterial count of 1.2E+07 (± 0.25E+07) for Group 1 and of 7.2E+04 (± 14.4E+04) for Group 2 was found, with a high level of significance, p = .0001. CONCLUSIONS: Within the limitations of this study it can be concluded that bacterial species from human saliva may penetrate along the implant-abutment interface in both connections, however the cemented connection implants showed the lowest amount of bacterial colonization

Mineralisation of 2,4-dichlorophenoxyacetic acid by acoustic or hydrodynamic cavitation in conjunction with the advanced Fenton process

The mineralisation of 2,4-dichlorophenoxyacetic acid (2,4-D) in the presence of zero-valent iron and hydrogen peroxide (the Advanced Fenton process – AFP) whilst being subjected to acoustic or hydrodynamic cavitation is reported. If the reaction is merely stirred then there is 57% removal of TOC whilst on irradiation the figure is 64% although the latter reaction is more rapid. Use of ultrasound alone results in only 11% TOC removal in 60 min of treatment time. Addition of iron powder marginally enhances the extent of degradation but an appreciable increase is observed in the presence of hydrogen peroxide which acts as a source for hydroxyl radicals by Fenton chemistry as well as by dissociation in the presence of ultrasound. The use of hydrodynamic cavitation in conjunction with the advanced Fenton process has also been found to be a useful tool for continuous remediation of water contaminated with 2,4-D. After 20 minutes of treatment the residual TOC is reduced to 30% and this probably represents the remaining highly recalcitrant small organic molecules