Statistical similarity between the compression of a porous material and earthquakes

It has been long stated that there are profound analogies between fracture experiments and earthquakes; however, few works attempt a complete characterization of the parallelisms between these so separate phenomena. We study the Acoustic Emission events produced during the compression of Vycor (SiO&sub&2&/sub&). The Gutenberg-Richter law, the modified Omori's law, and the law of aftershock productivity hold for a minimum of 5 decades, are independent of the compression rate, and keep stationary for all the duration of the experiments. The waiting-time distribution fulfills a unified scaling law with a power-law exponent close to 2.45 for long times, which is explained in terms of the temporal variations of the activity rate.

The cervico-thoracic outlet compression syndrome. Analysis of surgical treatment.

Surgical treatment of the thoracic outlet compression syndrome is being presently reconsidered. Until these last few years, there was the choice between two interventions only: scalenotomy, a simple operation entailing no complication, but with a 60% recurrence rate--or the resection of the first rib through an axillary approach, an efficacious intervention which caused, however, serious nervous complications in 14% of treated cases. The follow-up of 75 cases operated for a TOCS reveals to the authors that--all techniques taken into account--results are unsatisfactory in 33% of cases. These failures are due either to technical deficiencies, or to a complication arising in the course of the operation, or to an erroneous diagnosis. The authors resort to surgery only to treat serious vascular syndromes (absolute indication) or invalidating neurological compression syndromes, after failure of physical therapy (relative indication). They propose a cervical approach--the only one enabling a safe dissection of the brachial plexus--a partial scalenectomy, resection of all fibrous bands pressing on nervous trunks, or the resection of a cervical rib. Should the costo-clavicular space appear anatomically too narrow, the first rib, already partially freed by the cervical approach, will be resected through the axillary route.

Safety and efficacy in gamma knife radiosurgery for trigeminal neuralgia due to megadolichbasilar artery compression: a prospective series of 29 consecutive patients

Purpose: To analyse prospectively the long-term results of Gamma Knife surgery (GKS) in patients with trigeminal neuralgia secondary to megadolichobasilar artery (MBA). Methods: Between December 1992 and November 2010, 33 consecutive patients presenting with ITN secondary to MBA were operated by GKS and followed prospectively in Timone University Hospital. The follow up is at least of 1 year in 29 patients. The median age was 74.90 years (range 51 to 90). The GKS typically was performed using MR and CT imaging guidance and a single 4 mm isocenter. The median of the prescription dose (at the 100%) was 90 Gy (range 80 to 90). The target was placed on the cisternal portion of the Vth nerve. Clinical and dosimetric parameters were analyzed. GKS was the first surgical procedure in 23 patients (79.31%). Results: The median follow- up period was 46.12 months (range 12.95 to 157.93). All the 29 patients (100%) were initially pain free in a median time of 13.5 days (range 0 to 240). The probability of remaining pain free at 0.5, 1, 2 years was 93.1%, 79.3% and 75.7% respectively, reaching at this time the flat part of the curve. Seven patients (24.13%) experienced a recurrence with a median delay of 10.75 months (range 3.77 to 12.62). The actuarial rate of recurrence was not higher than in our population with essential TN although atypical pain was associated with a much higher risk of recurrence (HR= 6.92, p= 0.0117). The hypoesthesia actuarial rates at 0.5 years was 4.3% and at 1 year reach 13% and remains stable till 12 years with a median delay of onset of 7 (5, 12) months. Female patients had a statistically much lower probability of developing a facial numbness (p of 0.03). No patient reported a bothersome hypoesthesia. Conclusion: Retrogaserian, high dose GKS, turned out to be very safe with only 13.04% hypoesthesia, which was never disabling (0%), while achieving high quality pain control. The majority of the patients demonstrated a prolonged effect of radiosurgery in absence of any trigeminal nerve disturbance.

Space for thought: Representation of body boundaries and intellectual efficiency in children

Aim: The psychoanalytic theories of Bion, Anzieu, Berger and Gibello postulate that the development of thinking depends upon the formation of a psychic space. This thinking space has its origin in the body and in our interpersonal relations. This study aims to validate this psychodynamic hypothesis. Method: A group of 8- to 14-year-old children participated in this research. The presence of a thinking space was operationalized by the "barrier" and "penetration" scores on the Rorschach's Fisher and Cleveland scales and intellectual efficiency was measured using a short version of the WISC-IV. Results: Results show that extreme scores on the "barrier" and "penetration" variables predict a lower intellectual level than average scores on the same variables. Conclusion: The development of thinking and personality are undoubtedly linked and the "barrier" and "penetration" variables are useful measures when evaluating the development of a space for thought.

Interplay of spectral efficiency, power and doppler spectrum for reference-signal-assisted wireless communication

Expressions relating spectral efficiency, power, and Doppler spectrum, are derived for Rayleigh-faded wireless channels with Gaussian signal transmission. No side information on the state of the channel is assumed at the receiver. Rather, periodic reference signals are postulated in accordance with the functioning of most wireless systems. The analysis relies on a well-established lower bound, generally tight and asymptotically exact at low SNR. In contrast with most previous studies, which relied on block-fading channel models, a continuous-fading model is adopted. This embeds the Doppler spectrum directly in the derived expressions, imbuing them with practical significance. Closed-form relationships are obtained for the popular Clarke-Jakes spectrum and informative expansions, valid for arbitrary spectra, are found for the low- and high-power regimes. While the paper focuses on scalar channels, the extension to multiantenna settings is also discussed.

Spectral efficiency in reference-signal-assisted low-power wireless communication

Expressions relating spectral efficiency, power and Doppler spectrum are derived for low-power Rayleighfaded wireless channels with proper complex signaling. Noside information on the state of the channel is assumed at the receiver. Rather, periodic reference signals are postulated inaccordance with the functioning of most wireless systems. In contrast with most previous studies, which relied on block-fading channel models, a continuous-fading model is adopted. This embeds the Doppler spectrum directly in thederived expressions thereby imbuing them with practical significance.

Efficiency-based evaluation of aligners for industrial applications

This paper presents a novel efficiencybased evaluation of sentence and word aligners. This assessment is critical in order to make a reliable use in industrial scenarios. The evaluation shows that the resourcesrequired by aligners differ rather broadly. Subsequently, we establish limitation mechanisms on a set of aligners deployed as web services. These results, paired with the quality expected from the aligners, allow providers to choose the most appropriate aligner according to the task at hand.

Social Security in Theory and Practice (II): Efficiency Theories, Narrative Theories, and Implications for Reform

166 countries have some kind of public old age pension. What economic forces create and sustain old age Social Security as a public program? Mulligan and Sala-i-Martin (1999b) document several of the internationally and historically common features of social security programs, and explore "political" theories of Social Security. This paper discusses the "efficiency theories", which view creation of the SS program as a full of partial solution to some market failure. Efficiency explanations of social security include the "SS as welfare for the elderly" the "retirement increases productivity to optimally manage human capital externalities", "optimal retirement insurance", the "prodigal father problem", the "misguided Keynesian", the "optimal longevity insurance", the "government economizing transaction costs", and the "return on human capital investment". We also analyze four "narrative" theories of social security: the "chain letter theory", the "lump of labor theory", the "monopoly capitalism theory", and the "Sub-but-Nearly-Optimal policy response to private pensions theory". The political and efficiency explanations are compared with the international and historical facts and used to derive implications for replacing the typical pay-as-you-go system with a forced savings plan. Most of the explanations suggest that forced savings does not increase welfare, and may decrease it.

Adverse Selection, Credit, and Efficiency: the Case of the Missing Market

We analyze a standard environment of adverse selection in credit markets. In our envi- ronment, entrepreneurs who are privately informed about the quality of their projects need to borrow from banks. As is generally the case in economies with adverse selection, the competitive equilibrium of our economy is shown to be ine¢ cient. Under adverse selection, the choices made by one type of agents limit what can be o¤ered to other types in an incentive-compatible manner. This gives rise to an externality, which cannot be internalized in a competitive equilibrium. We show that, in this type of environment, the ine¢ ciency associated to adverse selection is the consequence of one implicit assumption: entrepreneurs can only borrow from banks. If an additional market is added (say, a .security market.), in which entrepreneurs can obtain funds beyond those o¤ered by banks, we show that the e¢ cient allocation is an equilibrium of the economy. In such an equilibrium, all entrepreneurs borrow at a pooling rate in the security market. When they apply to bank loans, though, only entrepreneurs with good projects pledge these additional funds as collateral. This equilibrium thus simultaneously entails cross- subsidization and separation between di¤erent types of entrepreneurs.

Intraoral open reduction and internal fixation of displaced mandibular angle fractures using a specific ad hoc reduction-compression forceps: a preliminary study

OBJECTIVES: To preliminarily evaluate prospectively the accuracy and reliability of a specific ad hoc reduction-compression forceps in intraoral open reduction of transverse and displaced mandibular angle fractures. STUDY DESIGN: We analyzed the clinical and radiologic data of 7 patients with 7 single transverse and displaced angle fractures. An intraoral approach was performed in all of the patients without using perioperative intermaxillary fixation. A single Arbeitsgemeinschaft Osteosynthese (AO) unilock reconstruction plate was fixed to each stable fragment with 3 locking screws (2.0 mm in 5 patients and 2.4 mm in 2 patients) at the basilar border of the mandible, according to AO/American Society of Internal Fixation (ASIF) principles. Follow-up was at 1, 3, 6, and 12 months, and we noted the status of healing and complications, if any. RESULTS: All of the patients had satisfactory fracture reduction as well as a successful treatment outcome without complications. CONCLUSION: This preliminary study demonstrated that the intraoral reduction of transverse and displaced angle fractures using a specific ad hoc reduction-forceps results in a high rate of success.

Adverse selection, credit, and efficiency: the case of the missing market

We analyze a standard environment of adverse selection in credit markets. In our environment, entrepreneurs who are privately informed about the quality of their projects need to borrow in order to invest. Conventional wisdom says that, in this class of economies, the competitive equilibrium is typically inefficient. We show that this conventional wisdom rests on one implicit assumption: entrepreneurs can only access monitored lending. If a new set of markets is added to provide entrepreneurs with additional funds, efficiency can be attained in equilibrium. An important characteristic of these additional markets is that lending in them must be unmonitored, in the sense that it does not condition total borrowing or investment by entrepreneurs. This makes it possible to attain efficiency by pooling all entrepreneurs in the new markets while separating them in the markets for monitored loans.

Communication, Coordination, and Efficiency in Evolutionary One-population Models

We analyze the role of commitment in pre-play communication for ensuring efficient evolutionarily stable outcomes in coordination games. All players are a priori identical as they are drawn from the same population. In games where efficient outcomes can be reached by players coordinating on the same action we find commitment to be necessary to enforce efficiency. In games where efficienct outcomes only result from play of different actions, communication without commitment is most effective although efficiency can no longer be guaranteed. Only when there are many messages then inefficient outcomes are negligible as their basins of attraction become very small.

Efficiency of recombinant human TNF in human cancer therapy.

Recombinant human tumour necrosis factor (TNF) has a selective effect on angiogenic vessels in tumours. Given that it induces vasoplegia, its clinical use has been limited to administration through isolated limb perfusion (ILP) for regionally advanced melanomas and soft tissue sarcomas of the limbs. When combined with the alkylating agent melphalan, a single ILP produces a very high objective response rate. In melanoma, the complete response (CR) rate is around 80% and the overall objective response rate greater than 90%. In soft tissue sarcomas that are inextirpable, ILP is a neoadjuvant treatment resulting in limb salvage in 80% of the cases. The CR rate averages 20% and the objective response rate is around 80%. The mode of action of TNF-based ILP involves two distinct and successive effects on the tumour-associated vasculature: first, an increase in endothelium permeability leading to improved chemotherapy penetration within the tumour tissue, and second, a selective killing of angiogenic endothelial cells resulting in tumour vessel destruction. The mechanism whereby these events occur involves rapid (of the order of minutes) perturbation of cell-cell adhesive junctions and inhibition of alphavbeta3 integrin signalling in tumour-associated vessels, followed by massive death of endothelial cells and tumour vascular collapse 24 hours later. New, promising approaches for the systemic use of TNF in cancer therapy include TNF targeting by means of single chain antibodies or endothelial cell ligands, or combined administration with drugs perturbing integrin-dependent signalling and sensitizing angiogenic endothelial cells to TNF-induced death.