Stochastic Schroedinger equations and applications to Ehrenfest-type theorems

We study stochastic evolution equations describing the dynamics of open quantum systems. First, using resolvent approximations, we obtain a sufficient condition for regularity of solutions to linear stochastic Schroedinger equations driven by cylindrical Brownian motions applying to many physical systems. Then, we establish well-posedness and norm conservation property of a wide class of open quantum systems described in position representation. Moreover, we prove Ehrenfest-type theorems that describe the evolution of the mean value of quantum observables in open systems. Finally, we give a new criterion for existence and uniqueness of weak solutions to non-linear stochastic Schroedinger equations. We apply our results to physical systems such as fluctuating ion traps and quantum measurement processes of position

A Simulation Framework for Fast Design Space Exploration of Unmanned Air System Traffic Management Policies

The number of daily small Unmanned Aircraft Systems (sUAS) operations in uncontrolled low altitude airspace is expected to reach into the millions. UAS Traffic Management (UTM) is an emerging concept aiming at the safe and efficient management of such very dense traffic, but few studies are addressing the policies to accommodate such demand and the required ground infrastructure in suburban or urban environments. Searching for the optimal air traffic management policy is a combinatorial optimization problem with intractable complexity when the number of sUAS and the constraints increases. As the demands on the airspace increase and traffic patterns get complicated, it is difficult to forecast the potential low altitude airspace hotspots and the corresponding ground resource requirements. This work presents a Multi-agent Air Traffic and Resource Usage Simulation (MATRUS) framework that aims for fast evaluation of different air traffic management policies and the relationship between policy, environment and resulting traffic patterns. It can also be used as a tool to decide the resource distribution and launch site location in the planning of a next-generation smart city. As a case study, detailed comparisons are provided for the sUAS flight time, conflict ratio, cellular communication resource usage, for a managed (centrally coordinated) and unmanaged (free flight) traffic scenario.Comment: The Integrated Communications Navigation and Surveillance (ICNS) Conference in 201

Impact of Salvage Surgery and Re-irradiation for Radiation Failed Recurrent Skull Base Meningiomas

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Bringing Pedagogical Innovation into the University Campus: Promoting students' Critical Thinking and Teachers' Practices

[EN]Regardless of the relevance that universities around the world bestow on it today, there are still efforts being made to assure the effective inclusion of critical thinking in university classrooms. Thus, the promotion of critical thinking is considered to be pedagogical innovation. In this chapter, we focus on pedagogical innovation in higher education, more specifically, on teaching practices aimed at the deliberate, explicit, and systematic promotion of students' critical thinking. We put forward the example from two different universities in two different countries – Portugal and Spain – of how critical thinking can be fostered via teaching-learning strategies that are oriented to its effective promotion. From the analysis of both cases of good practices, we identify a set of theoretical and practical guidelines to assist university teachers who wish to invite critical thinking into their classrooms. Considerations are offered regarding the importance of including critical thinking in faculty development. To make the promotion of critical thinking viable and sustainable, before teaching to engender critical thinking, teachers themselves need opportunities to learn how to do so

A Multiple System of Radio Sources at the Core of the L723 Multipolar Outflow

We present high angular resolution Very Large Array multi-epoch continuum observations at 3.6 cm and 7 mm towards the core of the L723 multipolar outflow revealing a multiple system of four radio sources suspected to be YSOs in a region of only ~4 arcsecs (1200 AU) in extent. The 3.6 cm observations show that the previously detected source VLA 2 contains a close (separation ~0.29 arcsecs or ~90 AU) radio binary, with components (A and B) along a position angle of ~150 degrees. The northern component (VLA 2A) of this binary system is also detected in the 7 mm observations, with a positive spectral index between 3.6 cm and 7 mm. In addition, the source VLA 2A is associated with extended emission along a position angle of ~115 degrees, that we interpret as outflowing shock-ionized gas that is exciting a system of HH objects with the same position angle. A third, weak 3.6 cm source, VLA 2C, that is detected also at 7 mm, is located ~0.7 arcsecs northeast of VLA 2A, and is possibly associated with the water maser emission in the region. The 7 mm observations reveal the presence of an additional source, VLA 2D, located ~3.5 arcsecs southeast of VLA 2A, and with a 1.35 mm counterpart. All these radio continuum sources have a positive spectral index, compatible with them being YSOs. We also propose that the high velocity CO emission observed in the region could be the superposition of multiple outflows (at least three independent bipolar outflows) excited by the YSOs located at the core, instead of the previous interpretations in terms of only one or two outflows.Comment: Accepted for publication in The Astrophysical Journal (2007 December 6

Not Waving but Striving: Research Collaboration in the Context of Stratification, Segmentation, and the Quest for Prestige

In this article we examine the ways in which institutional stratification and academic labor segmentation contribute to shaping faculty collaborative activities. We draw on interviews from science and engineering faculty at two institutions in the United States to highlight how collaboration, as an essential form of academic labor, is shaped by institutional factors like resource stress and isomorphic pressures to fit the ideal of the “world-class” research-intensive university. The findings suggest that a university’s relative position in the institutional status hierarchy has a significant impact on the types of resources faculty seeking to establish collaborations can access and mobilize, thus reinforcing existing patterns of institutional stratification where “striving” institutions can never catch up to their more prestigious peers. At the same time, the pressure to maximize institutional prestige can create paradoxical interinstitutional dynamics where seemingly successful “Mode 2” units that rely almost exclusively on external resources and partnerships with industry are expected to mold themselves more closely to the activity streams of traditional academic units

Constraint on the time variation of the fine-structure constant with the SDSS-III/BOSS DR12 quasar sample

From the Sloan Digital Sky Survey (SDSS) Data Release 12, which covers the full Baryonic Oscillation Spectroscopic Survey (BOSS) footprint, we investigate the possible variation of the fine-structure constant over cosmological time-scales. We analyse the largest quasar sample considered so far in the literature, which contains 13175 spectra (10363 from SDSS-III/BOSS DR12 + 2812 from SDSS-II DR7) with redshift $z<\,$1. We apply the emission-line method on the [O III] doublet (4960, 5008 A) and obtain $\Delta\alpha/\alpha= \left(0.9 \pm 1.8\right)\times10^{-5}$ for the relative variation of the fine-structure constant. We also investigate the possible sources of systematics: misidentification of the lines, sky OH lines, H$\,\beta$ and broad line contamination, Gaussian and Voigt fitting profiles, optimal wavelength range for the Gaussian fits, chosen polynomial order for the continuum spectrum, signal-to-noise ratio and good quality of the fits. The uncertainty of the measurement is dominated by the sky subtraction. The results presented in this work, being systematics limited, have sufficient statistics to constrain robustly the variation of the fine-structure constant in redshift bins ($\Delta z\approx$ 0.06) over the last 7.9 Gyr. In addition, we study the [Ne III] doublet (3870, 3969 A) present in 462 quasar spectra and discuss the systematic effects on using these emission lines to constrain the fine-structure constant variation. Better constraints on $\Delta\alpha/\alpha\$ ($<$10$^{-6}$) using the emission-line method would be possible with high-resolution spectroscopy and large galaxy/qso surveys.Comment: 16 pages, 16 figures. Version published in MNRAS. Analysis enlarged, public catalogue now availabl

Towards sustainable agriculture: A critical analysis of agrobiodiversity assessment methods and recommendations for effective implementation

Agriculture intensification has driven the loss of biodiversity at a global level. The imple- mentation of strategies to conserve and promote biodiversity in agricultural areas can be favoured by adequate assessment methods that foster the awareness of decision makers about the impact of management practices. This paper presents a state-of-the-art review of assessment methods of the overall biodiversity in agricultural systems, focusing on the quantitative methods applied, indicators of biodiversity, and functionalities. It was concluded that compensation effects and difficulties in in- terpretation are associated with currently common methodologies of composite indicator calculation to assess biodiversity performance. This review allowed for the identification and critical analysis of current methodologies for biodiversity assessments in the agricultural sector, and it highlighted the need for more implementation-oriented approaches. By providing recommendations on what should be considered when formulating biodiversity assessment methods, this study can contribute to the formulation of appropriate assessment frameworks for agricultural management policies and strategies.info:eu-repo/semantics/publishedVersio