Outgassing, Temperature Gradients and the Radiometer Effect in LISA: A Torsion Pendulum Investigation

Thermal modeling of the LISA gravitational reference sensor (GRS) includes such effects as outgassing from the proof mass and its housing and the radiometer effect. Experimental data in conditions emulating the LISA GRS are required to confidently predict the GRS performance. Outgassing and the radiometer effect are similar in characteristics and are difficult to decouple experimentally. The design of our torsion balance allows us to investigate differential radiation pressure, the radiometer effect, and outgassing on closely separated conducting surfaces with high sensitivity. A thermally controlled split copper plate is brought near a freely hanging plate-torsion pendulum.We have varied the temperature on each half of the copper plate and have measured the resulting forces on the pendulum. We have determined that to first order the current GRS model for the radiometer effect, outgassing, and radiation pressure are mostly consistent with our torsion balance measurements and therefore these thermal effects do not appear to be a large hindrance to the LISA noise budget. However, there remain discrepancies between the predicted dependence of these effects on the temperature of our apparatus.Comment: 6th International LISA Symposiu

Discrete Bulk Reconstruction

According to the AdS/CFT correspondence, the geometries of certain spacetimes are fully determined by quantum states that live on their boundaries -- indeed, by the von Neumann entropies of portions of those boundary states. This work investigates to what extent the geometries can be reconstructed from the entropies in polynomial time. Bouland, Fefferman, and Vazirani (2019) argued that the AdS/CFT map can be exponentially complex if one wants to reconstruct regions such as the interiors of black holes. Our main result provides a sort of converse: we show that, in the special case of a single 1D boundary, if the input data consists of a list of entropies of contiguous boundary regions, and if the entropies satisfy a single inequality called Strong Subadditivity, then we can construct a graph model for the bulk in linear time. Moreover, the bulk graph is planar, it has $O(N^2)$ vertices (the information-theoretic minimum), and it's ``universal,'' with only the edge weights depending on the specific entropies in question. From a combinatorial perspective, our problem boils down to an ``inverse'' of the famous min-cut problem: rather than being given a graph and asked to find a min-cut, here we're given the values of min-cuts separating various sets of vertices, and need to find a weighted undirected graph consistent with those values. Our solution to this problem relies on the notion of a ``bulkless'' graph, which might be of independent interest for AdS/CFT. We also make initial progress on the case of multiple 1D boundaries -- where the boundaries could be connected via wormholes -- including an upper bound of $O(N^4)$ vertices whenever a planar bulk graph exists (thus putting the problem into the complexity class $\mathsf{NP}$).Comment: 41 pages, 18 figures. Comments welcomed! v2: new corollaries 2.3 and 4.5 with more explicit discussions of computability, additional references and discussio

The Evolution of the Auditor and Auditing Profession: The Impact of the Sarbanes-Oxley Act of 2002

The Sarbanes-Oxley Act of 2002 (SOX) was arguably the most influential piece of legislation passed to affect the accounting profession. Over the past nearly two decades since SOX was enacted, the auditor and auditing profession has evolved. The public’s perceptions of auditors and the profession have improved as a result of major legislation such as the Sarbanes-Oxley Act of 2002. This paper explores the evolution of the auditor and audit profession over the course of three different time periods to understand the function of the auditor. This paper is broken down into four major components. First, this paper explores what led to the need for reform in the auditing world. It discusses the large scandals and audit failures in the profession that prompted the passage of SOX. Next, this paper examines what exactly the Sarbanes-Oxley Act is. It examines the legislation and highlights the major reforms and restrictions it enacted on the auditing profession. Then, it discusses how SOX is doing at meeting its goals and objectives. This paper includes a discussion on how the audit profession looks years after the passage of such an influential regulation. Finally, the paper addresses the modern-day auditor and audit profession. This paper also discusses how the public views the role of the auditor and how SOX contributes to public perceptions. The goal of this paper is to examine the evolution of the auditing profession from a period of disappointment and unethical behavior to its current state of performance

LISA Science Results in the Presence of Data Disturbances

Each spacecraft in the Laser Interferometer Space Antenna houses a proof mass which follows a geodesic through spacetime. Disturbances which change the proof mass position, momentum, and/or acceleration will appear in the LISA data stream as additive quadratic functions. These data disturbances inhibit signal extraction and must be removed. In this paper we discuss the identification and fitting of monochromatic signals in the data set in the presence of data disturbances. We also present a preliminary analysis of the extent of science result limitations with respect to the frequency of data disturbances

Extreme tunability of interactions in a 7^7Li Bose-Einstein condensate

We use a Feshbach resonance to tune the scattering length a of a Bose-Einstein condensate of 7Li in the |F = 1, m_F = 1> state. Using the spatial extent of the trapped condensate we extract a over a range spanning 7 decades from small attractive interactions to extremely strong repulsive interactions. The shallow zero-crossing in the wing of the Feshbach resonance enables the determination of a as small as 0.01 Bohr radii. In this regime, evidence of the weak anisotropic magnetic dipole interaction is obtained by comparison with different trap geometries

Building for a Nature-Oriented Spirituality : a gathering for the cross-quarters

Thesis (M. Arch.)--Massachusetts Institute of Technology, Dept. of Architecture, 1991.Includes bibliographical references (p. 81-82).This thesis is a proposal for a way of building for a Nature-Oriented Spirituality. It begins an exploration into what a community might look like for people who see the land and the seasons as the generators of life. This process requires that the link between belief and physical form be made explicit and what this implies about the places that we make and inhabit. The project is a Ritual Community, a home and gathering place for the EarthSpirit Community. EarthSpirit is a New England based organization of individuals and groups whose beliefs are based generally on pre-Judeo / Christian myths and traditions, especially those of northern Europe and the British Isles. It is a spiritual construct quite different than that of the society at large, with profound implications both for the social and built environment. Since the late Middle Ages the practice of these beliefs has been out of necessity secretive and underground. Therefore there is no modern and little historical built precedence from which to start. The development of an attitude about both the landscape and how to place buildings within it is the central issue of this thesis. Rather than being prescriptive, an attitude provides guidance in how to approach the design and building processes without requiring use of a specific "style" of constructional system. By attuning the attitude toward physical form with the general attitudes and beliefs of a community, the outcome of the building process should provide an appropriate environment for that communitie's life and activities. The basic Pagan and Wiccan beliefs are an understanding and abstraction of Nature and the cycles of the seasons. Building a community for Pagans and Witches implies that appropriate attitudes can be found in understanding how the landscape behaves and using that understanding as the basis for building. Since the community accepts the physical character of the Universe as real and important, it is that which we can experience in the world that should guide how we integrate ourselves into Nature. We too are part of nature, not outside of it, and so part of building is finding a balance between the willful act of changing the environment to support us and allowing the land to continue on with its own business of fertility, growth, decline and death. The narrative character of shared symbols and geometries also have a place in the making of the built environment, their purpose to tell a story, to provide specific associations with the beliefs of the community. Where the narrative character of the building is it's most important feature, such as in the Ritual Building, these will come into use directly. In general. however, it is what we learn from the landscape which will generate an appropriate building method.by Scott R. Pollack.M.Arch

Contemporary NSTEMI management: the role of the hospitalist.

Non-ST-segment elevation myocardial infarction (NSTEMI) is defined as elevated cardiac biomarkers of necrosis in the absence of persistent ST-segment elevation in the setting of anginal symptoms or other acute event. It carries a poorer prognosis than most ST-segment elevation events, owing to the typical comorbidity burden of the older NSTEMI patients as well as diverse etiologies that add complexity to therapeutic decision-making. It may result from an acute atherothrombotic event (\u27Type 1\u27) or as the result of other causes of mismatch of myocardial oxygen supply and demand (\u27Type 2\u27). Regardless of type and other clinical factors, the hospital medicine specialist is increasingly responsible for managing or coordinating the care of these patients. Following published guidelines for risk stratification and basing anti-anginal, anticoagulant, antiplatelet, other pharmacologic therapies, and overall management approach on that individualized patient risk assessment can be expected to result in better short- and long-term clinical outcomes, including near-term readmission and recurrent events. We present here a review of the evidence basis and expert commentary to assist the hospitalist in achieving those improved outcomes in NSTEMI. Given that the Society for Hospital Medicine cites care of patients with acute coronary syndrome as a core competency for hospitalists, it is essential that those specialists stay current on optimal NSTEMI care

Deciphering the Origin of the Regular Satellites of Gaseous Giants - Iapetus: the Rosetta Ice-Moon

Here we show that Iapetus can serve to discriminate between satellite formation models. Its accretion history can be understood in terms of a two-component gaseous subnebula, with a relatively dense inner region, and an extended tail out to the location of the irregular satellites, as in the SEMM model of Mosqueira and Estrada (2003a,b). Following giant planet formation, planetesimals in the feeding zone of Jupiter and Saturn become dynamically excited, and undergo a collisional cascade. Ablation and capture of planetesimal fragments crossing the gaseous circumplanetary disks delivers enough collisional rubble to account for the mass budgets of the regular satellites of Jupiter and Saturn. This process can result in rock/ice fractionation provided the make up of the population of disk crossers is non-homogeneous, thus offering a natural explanation for the marked compositional differences between outer solar nebula objects and those that accreted in the subnebulae of the giant planets. Consequently, our model leads to an enhancement of the ice content of Iapetus, and to a lesser degree those of Ganymede, Titan and Callisto, and accounts for the (non-stochastic) compositions of these large, low-porosity outer regular satellites of Jupiter and Saturn. (abridged)Comment: 33 pages, 7 figures, 2 tables, Accepted for publication to Icaru