Notes on High Energy Limit of Bosonic Closed String Scattering Amplitudes

We study bosonic closed string scattering amplitudes in the high-energy limit. We find that the methods of decoupling of high-energy zero-norm states and the high-energy Virasoro constraints, which were adopted in the previous works to calculate the ratios among high-energy open string scattering amplitudes of different string states, persist for the case of closed string. However, we clarify the previous saddle-point calculation for high-energy open string scattering amplitudes and claim that only (t,u) channel of the amplitudes is suitable for saddle-point calculation. We then discuss three evidences to show that saddle-point calculation for high-energy closed string scattering amplitudes is not reliable. By using the relation of tree-level closed and open string scattering amplitudes of Kawai, Lewellen and Tye (KLT), we calculate the high-energy closed string scattering amplitudes for arbitrary mass levels. For the case of high-energy closed string four-tachyon amplitude, our result differs from the previous one of Gross and Mende, which is NOT consistent with KLT formula, by an oscillating factor.Comment: 14 pages, no figure. Equations and Conclusion adde

Stringy Symmetries and Their High-energy Limits

We derive stringy symmetries with conserved charges of arbitrarily high spins from the decoupling of two types of zero-norm states in the old covariant first quantized (OCFQ) spectrum of open bosonic string. These symmetries are valid to all energy and all loop orders in string perturbation theory. The high-energy limit of these stringy symmetries can then be used to fix the proportionality constants between scattering amplitudes of different string states algebraically without referring to Gross and Mende's saddle point calculation of high-energy string-loop amplitudes. These proportionality constants are, as conjectured by Gross, independent of the scattering angle and the order of string perturbation theory. However, we also discover some new nonzero components of high-energy amplitudes not found previously by Gross and Manes. These components are essential to preserve massive gauge invariances or decouple massive zero-norm states of string theory. A set of massive scattering amplitudes and their high energy limit are calculated explicitly to justify our results.Comment: 10 pages. A corrected version of hep-th/0303012. Final version to appear in Phys. Lett.

Taking Back the Work: A Cooperative Inquiry into Leaders of Color in Movement-Building Organizations

Through the Leadership for a Changing World Research and Documentation program, a group of leaders of color committed to social justice came together to reflect on the specific obstacles leaders of color face as they engage in movement building and to find ways to overcome these barriers. Together they asked: How do we build, strengthen and sustain movement-building organizations led by people of color? In the report, the group has identified four strategies to help community-based leaders of color engage in "taking back the work," with examples of each based on their successful work in communities

Predicting Non-linear Cellular Automata Quickly by Decomposing Them into Linear Ones

We show that a wide variety of non-linear cellular automata (CAs) can be decomposed into a quasidirect product of linear ones. These CAs can be predicted by parallel circuits of depth O(log^2 t) using gates with binary inputs, or O(log t) depth if ``sum mod p'' gates with an unbounded number of inputs are allowed. Thus these CAs can be predicted by (idealized) parallel computers much faster than by explicit simulation, even though they are non-linear. This class includes any CA whose rule, when written as an algebra, is a solvable group. We also show that CAs based on nilpotent groups can be predicted in depth O(log t) or O(1) by circuits with binary or ``sum mod p'' gates respectively. We use these techniques to give an efficient algorithm for a CA rule which, like elementary CA rule 18, has diffusing defects that annihilate in pairs. This can be used to predict the motion of defects in rule 18 in O(log^2 t) parallel time

Zero-norm states and High-energy Symmetries of String Theory

We derive stringy Ward identities from the decoupling of two types of zero-norm states in the old covariant first quantized (OCFQ) spectrum of open bosonic string. These Ward identities are valid to all energy and all loop orders in string perturbation theory. The high-energy limit of these stringy Ward identities can then be used to fix the proportionality constants between scattering amplitudes of different string states algebraically without referring to Gross and Mende's saddle point calculation of high-energy string-loop amplitudes. As examples, all Ward identities for the mass level 4 and 6 are derived, their high-energy limits are calculated and the proportionality constants between scattering amplitudes of different string states are determined. In addition to those identified before, we discover some new nonzero components of high-energy amplitudes not found previously by Gross and Manes. These components are essential to preserve massive gauge invariances or decouple massive zero-norm states of string theory. A set of massive scattering amplitudes and their high energy limits are calculated explicitly for each mass level to justify our results

High-energy String Scatterings of Compactified Open String

We calculate high-energy massive string scattering amplitudes of compactified open string. We derive infinite linear relations, or stringy symmetries, among soft high-energy string scattering amplitudes of different string states in the Gross kinematic regime (GR). In addition, we systematically analyze all hard power-law and soft exponential fall-off regimes of high-energy compactified open string scatterings by comparing the scatterings with their 26D noncompactified counterparts. In particular, we discover the existence of a power-law regime at fixed angle and an exponential fall-off regime at small angle for high-energy compactified open string scatterings. The linear relations break down as expected in all power-law regimes. The analysis can be extended to the high-energy scatterings of the compactified closed string, which corrects and extends the previous results in [28] .Comment: 16 pages, 1 table. v2:typos corrected,references added. v3,v4:Eq.(26) typos. Eq.(27) correcte

Clear: Conversations: A Collaborative Regional Project to Help Patients Improve their Health Visits

Objective: The National Network of Libraries of Medicine, New England Region’s Clear: Conversations project aimed to teach health literacy skills to help patients communicate better with their health care providers including how to: ask for simple language and slow down the provider, use teach-back, bring medications and supplements for a brown bag review, and get need-to-know information. Methods: Five organizations were awarded with Clear: Conversations materials that were adapted from a program created by Health Literacy Missouri. A highlight of the workshop was a role play between a health care provider and patient. Awardees were required to offer the workshop at least once, meet regularly via teleconference to get support in planning their programs and to learn from each other’s experiences, and provide a brief post-project report. Awardees also created and used pre- and post-workshop tests. Results: The program was offered at a variety of venues including a Healthy Start initiative, a senior center, a patient and family learning center, and a family life education center. A total of 109 individuals participated in the workshops. Pre- and post-workshop tests showed participants felt more comfortable to ask questions, slow down their doctor, and repeat back what the doctor said to make sure they understood. Conclusions : The NN/LM NER’s Clear: Conversations project was offered by a cross-disciplinary group of health information providers. It empowered participants with practical health literacy skills for better health care visits. Implications: The Clear: Conversations materials created by Health Literacy Missouri present an opportunity for librarians and other health information providers to empower patients with useful and essential health literacy skills

Negotiating the responsibilities of collaborative undergraduate fieldcourses

Undergraduate fieldcourses to destinations in the global South have received much critical scholarly and pedagogic attention. This article reflects on a third‐year Geography fieldcourse to Kenya, which aimed to collaborate with local partners in providing an immersive and co‐constitutive learning environment that transcended the politics of knowledge production defining the global South as a distanciated object of study. We shape our reflections on this fieldcourse through a conceptualisation of responsibility as a relational, inter‐subjective achievement borne out of negotiation and encounter. Focusing in particular on the trade‐offs that are required when taking into account different staff, students and partner organisations' positionalities, expectations and experiences, we argue that scholarship concerning the responsibilities of geographers' engagements with the global South needs to account for the emotional, embodied and affective challenges inherent in practising collaborative academic endeavour

The connections of the inferior colliculus and the organization of the brainstem auditory system in the greater horseshoe bat (Rhinolophus ferrumequinum)

The connections of the inferior colliculus, the mammalian midbrain auditory center, were determined in the greater horseshoe bat (Rhinolophus ferrumequinum), using the horseradish peroxidase method. In order to localize the auditory centers of this bat, brains were investigated with the aid of cell and fiber-stained material. The results show that most auditory centers are highly developed in this echolocating bat. However, the organization of the central auditory system does not generally differ from the mammalian scheme. This holds also for the organization of the superior olivary complex where a well-developed medial superior olivary nucleus was found. In addition to the ventral and dorsal nuclei of the lateral lemniscus a third well-developed nucleus has been defined which projects ipsilaterally to the inferior colliculus and which was called the intermediate nucleus of the lateral leminiscus. All nuclei of the central auditory pathway project ipsi-, contra-, or bilaterally to the central nucleus of the inferior colliculus with the exception of the medial nucleus of the trapezoid body and the medial geniculate body. The tonotopic organization of these projections and their possible functions are discussed in context with neurophysiological investigations

PHOTOCHEMICAL RING-OPENING IN meso-CHLORINATED CHLOROPHYLLS

Irradiation of 20-chloro-chlorophylls of the a-type with visible light produces long-wavelength shifted photoproducts, which transform in the dark to linear tetrapyrroles (bile pigments). The possible significance for chlorophyll degradation is discussed