Phenomenology of the minimal supersymmetric U(1)B−L×U(1)RU(1)_{B-L}\times U(1)_R extension of the standard model

We discuss the minimal supersymmetric $U(1)_{B-L}\times U(1)_R$ extension of the standard model. Gauge couplings unify as in the MSSM, even if the scale of $U(1)_{B-L}\times U(1)_R$ breaking is as low as order TeV and the model can be embedded into an SO(10) grand unified theory. The phenomenology of the model differs in some important aspects from the MSSM, leading potentially to rich phenomenology at the LHC. It predicts more light Higgs states and the mostly left CP-even Higgs has a mass reaching easily 125 GeV, with no constraints on the SUSY spectrum. Right sneutrinos can be the lightest supersymmetric particle, changing all dark matter constraints on SUSY parameter space. The model has seven neutralinos and squark/gluino decay chains involve more complicated cascades than in the MSSM. We also discuss briefly low-energy and accelerator constraints on the model, where the most important limits come from recent $Z'$ searches at the LHC and upper limits on lepton flavour violation.Comment: 46 pages, 11 figure

Understanding reverse osmosis polyamide active layer macrostructure and performance through indirect microscopic observation of film growth

Given the random nature of reverse osmosis polyamide macrostructure, it is difficult to understand the relationship between its structure and its separation characteristics. Many have addressed this subject and a few have reached significant conclusions to date. Acknowledging that membrane chemistry is the most important lever in controlling performance and not structure, to truly understand which features of the polyamide film can be manipulated to affect performance, there may be value in understanding its formation mechanism. Building upon a basic grasp of this mechanism, it may be possible to fine tune membrane performance through structure manipulation. While direct observation of polyamide film growth is not yet possible on a microscopic scale, new methods have been developed for indirect observation of the process. These methods, pseudo-stop-motion imaging and reactive post-polymerization potting, have provided valuable insight on the formation mechanism. The pseudo-stop-motion imaging technique was developed to view the polyamide structure on a microscopic scale at discrete points in time during the interfacial polymerization, from the first appearance of polyamide material on the support surface to the end of the polymerization. Essentially watching the process occur diminished the need for complex modeling to produce a basic growth hypothesis. Furthermore, the method can be used for any type of polyamide, and is limited only by the resolution of electron microscopy. Reactive post-polymerization potting is a technique developed to understand the structure of polyamide in its as-formed state. Historical microscopy has been performed on dried membranes, but not on films immediately following polymerization. The resulting structures are strikingly different from those observed in the literature via SEM and TEM, and when taken in context with the growth mechanism proposed from pseudo-stop-motion imaging, it further supports a mechanism of polyp inflation rather than continuous film formation. Well-controlled pilot-scale polyamide casting has been performed to corroborate the proposed mechanistic theory, and the theory will be framed within the broader context of polyamide membrane development

Pressure dependence of two-level systems in disordered atomic chain

The dependence of two-level systems in disordered atomic chain on pressure, both positive and negative was studied numerically. The disorder was produced through the use of interatomic pair potentials having more than one energy minimum. It was found that there exists a correlation between the energy separation of the minima of two-level systems Delta and the variation of this separation with pressure. The correlation may have either positive or negative sign, implying that the asymmetry of two-level systems may in average increase or decrease with pressure depending on the interplay of different interactions between atoms in disordered state. The values of Delta depend on the sign of pressure.Comment: 5 pages, 5 figure

Máquinas para agricultores familiares: ideias, inovações e criações apresentadas na 3ª Mostra de Máquinas e inventos.

bitstream/item/130184/1/EMBRAPA-CLIMA-TEMPERADO-LIVRO-MAQUINAS-PARA-AGRICULTORES-FAMILIARES.pdfPelotas, Embrapa Clima Temperado

Pan-European grading scales: lessons from national systems and the ECTS

This article assesses the impact of the Bologna Process on the grading schemes of EU member countries. In light of some problems regarding the implementation of the European Credit Transfer system (ECTS), the author proposes further reforms and offers some elements of a unified grading system for European higher education. The author explores the variation among Europe’s grading systems and the resulting lessons learned are shared here. Lastly, this article also argues that principles of justice and fairness, deemed central to academic freedom, are best upheld by the use of a unified grading system at national and European levels

Hybrid-procedures for the Treatment of Thoracoabdominal Aortic Aneurysms and Dissections

AimThe conventional open repair of thoracoabdominal aneurysms and dissections remains complex and demanding and is associated with significant morbidity and mortality. We present our experience of hybrid open and endovascular treatment of thoracoabdominal aneurysms and dissections.MethodsWithin an experience of 226 aortic stent-grafts between 1998 and April 2006, 6 of the patients (median age 60 years, range 35 to 68 years) with thoracoabdominal aneurysms (Crawford type I, II, III, and V) were treated with a combined endovascular and open surgical approach. Five men and one woman, with median aneurysm diameter of 75mm (range 70–100mm), received revascularization of the renal arteries, the superior mesenteric artery, and the coeliac trunk accomplished via transperitoneal bypass grafting. Aneurysmal exclusion was then performed by stent-graft deployment.ResultsThe entire procedure was technically successful in all patients. The patients were discharged a median of 9 days after the operation, while the postoperative studies revealed the patency of the vessels and no evidence of type I endoleak or secondary rupture of the aneurysm. During follow up (1 to 22 months) spiral-CT scanning revealed distinct shrinkage of the aneurysm, no graft migration or endoleak and patency of all revascularised vessels, except one renal artery in two patients. No patient experienced any temporary or permanent neurological deficit, and no dialysis was necessary.ConclusionThe combined endovascular and open surgical approach is feasible, without cross clamping of the aorta and with minimized ischemia time for renal and visceral arteries, and seems to be an appropriate strategy for patients with a thoraco-abdominal aortic aneurysm or dissection

Sub-cycle optical control of current in a semiconductor: from the multiphoton to the tunneling regime

Nonlinear interactions between ultrashort optical waveforms and solids can be used to induce and steer electric current on a femtosecond (fs) timescale, holding promise for electronic signal processing at PHz frequencies [Nature 493, 70 (2013)]. So far, this approach has been limited to insulators, requiring extremely strong peak electric fields and intensities. Here, we show all-optical generation and control of directly measurable electric current in a semiconductor relevant for high-speed and high-power (opto)electronics, gallium nitride (GaN), within an optical cycle and on a timescale shorter than 2 fs, at intensities at least an order of magnitude lower than those required for dielectrics. Our approach opens the door to PHz electronics and metrology, applicable to low-power (non-amplified) laser pulses, and may lead to future applications in semiconductor and photonic integrated circuit technologies

Design Hourly Volume Estimation at Freeway Nodes from Short-Term Traffic Counts

This paper extends the concept of a design hourly volume (DHV) which is derived from the ‘nth hour’ to a concept based on the nth highest saturated hour. To calculate this nth highest saturated hour at each ramp junction of a node, permanent traffic counts (PTC) are necessary on all ramps and the main lanes. In practice, such counts are often not available. For such cases, the German HCM proposes a method that enables the estimation of the design hourly volume through short-term traffic counts (STC) and the extrapolation of the results using available PTC in the vicinity. Within the scope of this study, it is examined how accurate the required nth highest saturated hour can be estimated with this method and similar concepts. Furthermore, it is investigated to what extent the number and the location of the available PTC affect the accuracy of the estimation. Scenarios without PTC are also considered. The evaluation is based on a database with a total of 72 freeway nodes for which PTC data from three years (2017-2019) are processed. The results show that the estimation of the nth highest saturated hour with the method of the German HCM works accurately, even if only one PTC is available on each inflowing approach. The results further indicate that STC are crucial to achieve accurate results when only few PTC are available. Acceptable results are also obtained by STC of one week, even without a projection at a PTC