Augmenting Architecture through Algorithmic Modeling

Algorithmic modeling has infiltrated schools of architecture over the last few years. It promises to not only revolutionize the possibilities of form making but also to establish immediate work flows of fabrication that explore performative based outcomes

Superstring Vertex Operators in an AdS_5 x S^5 Background

A quantizable action has recently been proposed for the superstring in an AdS_5 x S^5 background with Ramond-Ramond flux. In this paper, we construct physical vertex operators corresponding to on-shell fluctuations around the AdS_5 x S^5 background. The structure of these AdS_5 x S^5 vertex operators closely resembles the structure of the massless vertex operators in a flat background.Comment: 13 pages harvmac (large

Dual-mode Propulsion System Enabling Cubesat Exploration of the Solar System

It is apparent the cost of planetary exploration is rising as mission budgets are declining. Currently small scientific beds geared to performing limited tasks are being developed and launched into low earth orbit (LEO) in the form of small-scale satellite units, i.e., CubeSats. These micro- and nano-satellites are gaining popularity among the university and science communities due to their relatively low cost and design flexibility. To date these small units have been limited to performing tasks in LEO utilizing solar-based power. If a reasonable propulsion system could be developed, these CubeSat platforms could perform exploration of various extra-terrestrial bodies within the solar system engaging a broader range of researchers. Additionally, being mindful of mass, smaller cheaper launch vehicles (~1,000 kg to LEO) can be targeted. This, in effect, allows for beneficial exploration to be conducted within limited budgets.Researchers at the Center for Space Nuclear Research (CSNR) are proposing a low mass, radioisotope-based, dual-mode propulsion system capable of extending the exploration realm of these CubeSats out of LEO.The proposed radioisotope-based system would leverage the high specific energies [J/kg] associated with radioisotope materials and enhance their inherent low specific powers [W/g]. This is accomplished by accumulating thermal energy from nuclear decay within a central core over time. This allows for significant amounts of power to be transferred to a flowing gas over short periods of time. In the proposed configuration the stored energy can be utilized in two ways: (1) with direct propellant injection to the core, the energy can be converted into thrust through the use of a converging-diverging nozzle and (2) by flowing a working fluid through the core and subsequent Brayton engine, energy within the core can be converted to electrical energy. The first scenario achieves moderate ranges of thrust, but at a higher Isp than traditional chemical-based systems. The second scenario allows for the production of electrical power, which is then available for electric-based propulsion. Additionally, once at location the production of electrical power can be dedicated to the payload's communication system for data transfer. Ultimately, the proposed dual-mode propulsion platform capitalizes on the benefits of two types of propulsion methods the thrust of thermal propulsion ideal for quick orbital maneuvers and the specific impulse of electric propulsion ideal for efficient interplanetary travel. Overall, the system is functioning as a radioisotope thermal rocket (RTR).In this study the RTR concept is being developed as an in-space propulsion system to deliver a 6U CubeSat payload to the orbit of the Saturnian moon - Enceladus. Additionally, this study will develop an entire mission architecture for Enceladus targeting a total allowable launch mass of 1,000 kg

The Character of Pure Spinors

The character of holomorphic functions on the space of pure spinors in ten, eleven and twelve dimensions is calculated. From this character formula, we derive in a manifestly covariant way various central charges which appear in the pure spinor formalism for the superstring. We also derive in a simple way the zero momentum cohomology of the pure spinor BRST operator for the D=10 and D=11 superparticle.Comment: 42 pages, 2 picture

Ten-Dimensional Supergravity Constraints from the Pure Spinor Formalism for the Superstring

It has recently been shown that the ten-dimensional superstring can be quantized using the BRST operator $Q=\oint\lambda^\alpha d_\alpha$ where $\lambda^\alpha$ is a pure spinor satisfying $\lambda \gamma^m \lambda=0$ and $d_\alpha$ is the fermionic supersymmetric derivative. In this paper, the pure spinor version of superstring theory is formulated in a curved supergravity background and it is shown that nilpotency and holomorphicity of the pure spinor BRST operator imply the on-shell superspace constraints of the supergravity background. This is shown to lowest order in $\alpha'$ for the heterotic and Type II superstrings, thus providing a compact pure spinor version of the ten-dimensional superspace constraints for N=1, Type IIA and Type IIB supergravities. Since quantization is straightforward using the pure spinor version of the superstring, it is expected that these methods can also be used to compute higher-order $\alpha'$ corrections to the ten-dimensional superspace constraints.Comment: 30 pages late

Supporting Vermont Families in Packing Healthy Lunches for Children in Childcare

Introduction. Partnering with Hunger Free Vermont, an organization that works to end hunger and malnutrition across the state, we investigated the nutritional value of the packed meals parents provide for their children in early childcare. The USDA\u27s My Plate resource was used as a measure to assess variety, dividing foods into five groups: grains, dairy, vegetables, fruits, and protein. The results will help Hunger Free Vermont design nutrition education materials for childcare centers to provide to the families they serve. Methods. Online surveys were distributed, asking parents to report the foods they recently provided for their children in packed lunches, to rate how \u27healthy\u27 they thought those lunches were, and to note any barriers they experience to packing healthy foods. Results. Survey results showed that the average number of sweets packed by parents who had low confidence in their ability to pack healthy meals was significantly higher than the average number packed by parents with high confidence (p \u3c 0.05). Additionally, the total number of cited barriers was significantly higher in parents who had low confidence in their ability to pack healthy meals (p \u3c 0.01). Conclusions. Many parents cited time constraints and ‘picky’ children as barriers to providing healthy meals, with concerns about the expense of healthy items and lack of childcare for shopping or food-prep time following close behind. In the future, education materials that address children’s unhealthy food preferences or further investigations into barriers to providing healthy lunches may facilitate development of resources for Vermont families.https://scholarworks.uvm.edu/comphp_gallery/1259/thumbnail.jp

SMART Cables for Observing the Global Ocean: Science and Implementation

The ocean is key to understanding societal threats including climate change, sea level rise, ocean warming, tsunamis, and earthquakes. Because the ocean is difficult and costly to monitor, we lack fundamental data needed to adequately model, understand, and address these threats. One solution is to integrate sensors into future undersea telecommunications cables. This is the mission of the SMART subsea cables initiative (Science Monitoring And Reliable Telecommunications). SMART sensors would “piggyback” on the power and communications infrastructure of a million kilometers of undersea fiber optic cable and thousands of repeaters, creating the potential for seafloor-based global ocean observing at a modest incremental cost. Initial sensors would measure temperature, pressure, and seismic acceleration. The resulting data would address two critical scientific and societal issues: the long-term need for sustained climate-quality data from the under-sampled ocean (e.g., deep ocean temperature, sea level, and circulation), and the near-term need for improvements to global tsunami warning networks. A Joint Task Force (JTF) led by three UN agencies (ITU/WMO/UNESCO-IOC) is working to bring this initiative to fruition. This paper explores the ocean science and early warning improvements available from SMART cable data, and the societal, technological, and financial elements of realizing such a global network. Simulations show that deep ocean temperature and pressure measurements can improve estimates of ocean circulation and heat content, and cable-based pressure and seismic-acceleration sensors can improve tsunami warning times and earthquake parameters. The technology of integrating these sensors into fiber optic cables is discussed, addressing sea and land-based elements plus delivery of real-time open data products to end users. The science and business case for SMART cables is evaluated. SMART cables have been endorsed by major ocean science organizations, and JTF is working with cable suppliers and sponsors, multilateral development banks and end users to incorporate SMART capabilities into future cable projects. By investing now, we can build up a global ocean network of long-lived SMART cable sensors, creating a transformative addition to the Global Ocean Observing System

Lorentz-Covariant Green-Schwarz Superstring Amplitudes

In a recent paper, the BRST formalism for the gauge-fixed N=2 twistor-string was used to calculate Green-Schwarz supersring scattering amplitudes with an arbitrary number of loops and external massless states. Although the gauge-fixing procedure preserved the worldsheet N=2 superconformal invariance of the twistor-string, it broke the target-space SO(9,1) super-Poincar\'e invariance down to an SU(4)xU(1) subgroup. In this paper, generators for the SO(9,1) super-Poincar\'e transformations, as well as manifestly covariant vertex operators, are explicitly constructed out of the gauge-fixed matter fields. The earlier calculated amplitudes are then expressed in manifestly Lorentz-covariant notation.Comment: 11 pages plain Tex, KCL-TH-92-

Expressing dual concern in criticism for wrongdoing: The persuasive power of criticizing with care

To call attention to and motivate action on ethical issues in business or society, messengers often criticize groups for wrongdoing and ask these groups to change their behavior. When criticizing target groups, messengers frequently identify and express concern about harm caused to a victim group, and in the process address a target group by criticizing them for causing this harm and imploring them to change. However, we find that when messengers criticize a target group for causing harm to a victim group in this way—expressing singular concern for the victim group—members of the target group infer, often incorrectly, that the messenger views the target group as less moral and unworthy of concern. This inferred lack of moral concern reduces criticism acceptance and prompts backlash from the target group. To address this problem, we introduce dual concern messaging—messages that simultaneously communicate that a target group causes harm to a victim group and express concern for the target group. A series of several experiments demonstrate that dual concern messages reduce inferences that a critical messenger lacks moral concern for the criticized target group, increase the persuasiveness of the criticism among members of the target group, and reduce backlash from consumers against a corporate messenger. When pursuing justice for victims of a target group, dual concern messages that communicate concern for the victim group as well as the target group are more effective in fostering openness toward criticism, rather than defensiveness, in a target group, thus setting the stage for change