In this paper, we propose a paradigm of control, called a maximum hands-off control. A hands-off control is defined as a control that has a short support per unit time. The maximum hands-off control is the minimum support (or sparsest) per unit time among all controls that achieve control objectives. For finite horizon continuous-time control, we show the equivalence between the maximum hands-off control and L1-optimal control under a uniqueness assumption called normality. This result rationalizes the use of L1 optimality in computing a maximum hands-off control. The same result is obtained for discrete-time hands-off control. We also propose an L1/L2-optimal control to obtain a smooth hands-off control. Furthermore, we give a self-triggered feedback control algorithm for linear time-invariant systems, which achieves a given sparsity rate and practical stability in the case of plant disturbances. An example is included to illustrate the effectiveness of the proposed control.

Background: Joint replacement is a procedure with a major impact on the quality of life of patients with joint degenerative disease or traumatic injuries. However, some patients develop symptoms after the intervention caused by mechanical loosening or infection. Metabolic imaging by 18F-FDG-PET investigated in these patients isoften hampered by low specificity for diagnosis of possible septic vs. mechanical loosening. The reason for this shortcoming is to our opinion the unawareness of physiological remodeling processes that could be seen in asymptomatic patients. Objectives: In order to overcome this drawback, we aimed to find out the physiological metabolic functional pattern in asymptomatic patients with implanted hip prosthesis Patients and Methods: Twelve patients (6 males, 6 females); mean age 73 ± 7 (range 58 - 91) years were prospectively enrolled in the study. The patients were admitted to our department for oncological referral with implanted hip prostheses. All patients explained no symptoms with regard to their implanted prosthesis. The attenuation corrected images were used for analysis. Results: Fourteen hip prostheses in 12 patients were visually analyzed. Seven out of 14 prostheses among 12 patients showed focal periprosthetic enhanced metabolism, two of which showed two sites of enhanced uptake; whereas, the remaining five prostheses showed singular hypermetabolic areas within the periprosthetic site. The remaining seven prostheses in the other five patients showed no periprosthetic-enhanced uptake. Conclusion: Of the asymptomatic patients investigated, 58% showed focal enhanced periprosthetic glucose metabolism. This finding should be taken into consideration as a more probable unspecific metabolic pattern for correct interpretation of 18F-FDG-PET studies in patients with suspected septic loosening of the hip prosthesis.

The aim of this paper is to show how the German artistic ballad reflects the question of the social role of art and the artist in the second half of the 20th century, when – parallel with the affirmation of the concept of socially engaged and conscious art – the question of the status of an intellectual in society becomes very important. Within this study of German ballad, this literary and musical genre is understood as a short discursive form that deals with existential questions and stoned truths and values by means of apparently naive and simple presented events, offering in that way an opportunity for critical reflection in the act of reception. Two representative ballads are interpreted within this paper: Adorno's tongue (Adornos Zunge, 1965) from Gunter Grass and Ballad to the Poet Francois Villon (Ballade auf den Dichter Francois Villon, 1968) from Wolf Biermann. The immanent text interpretation of the two selected ballads shows the way in which literature, as an aesthetic response to reality, can offer the relevant critical perception of society, considering the historical moment of origin of the text as well as the philosophical and existential views of the author. DOI: 10.5901/mjss.2014.v5n13p257

We report a case of a 29-year-old primigravida at 36 weeks of gestation following an emergency caesarean section, complicated by respiratory distress and multiorgan failure secondary to superior vena cava (SVC) obstruction, requiring intubation and prolonged ventilatory support. The presented case highlights the consequences of delayed recognition of SVC obstruction due to a reluctance to undertake appropriate radiological imaging during pregnancy.