Apollo experience report: Onboard navigational and alignment software

The onboard navigational and alignment routines used during the nonthrusting phases of an Apollo mission are discussed as to their limitations, and alternate approaches that have more desirable capabilities are presented. A more efficient procedure for solving Kepler's equation, which is used in the calculation of Kepler's problem and Lambert's problem is included, and a sixth-order predictor scheme with a Runge-Kutta starter is recommended for numerical integration. The extension of the rendezvous navigation state to include angle biases and the use of a fixed coordinate system is also evaluated

An analysis of the effects of secondary reflections on dual-frequency reflectometers

The error-producing mechanism involving secondary reflections in a dual-frequency, distance measuring reflectometer is examined analytically. Equations defining the phase, and hence distance, error are derived. The error-reducing potential of frequency-sweeping is demonstrated. It is shown that a single spurious return can be completely nullified by optimizing the sweep width

Transverse electric scattering widths for strips-Fourier transform technique

A technique which is based on Fourier transformations is introduced for predicting scattering widths. For a strip it is shown that explicit determination of the linear current density is not necessary for bistatic or monostatic scattering width calculations. Comparisons of the predictions of the technique are made with the integral equation technique predictions, which do not require explicit evaluations of linear current densities

The HIV-1 Rev/RRE system is required for HIV-1 5' UTR cis elements to augment encapsidation of heterologous RNA into HIV-1 viral particles

Abstract Background The process of HIV-1 genomic RNA (gRNA) encapsidation is governed by a number of viral encoded components, most notably the Gag protein and gRNA cis elements in the canonical packaging signal (ψ). Also implicated in encapsidation are cis determinants in the R, U5, and PBS (primer binding site) from the 5' untranslated region (UTR). Although conventionally associated with nuclear export of HIV-1 RNA, there is a burgeoning role for the Rev/RRE in the encapsidation process. Pleiotropic effects exhibited by these cis and trans viral components may confound the ability to examine their independent, and combined, impact on encapsidation of RNA into HIV-1 viral particles in their innate viral context. We systematically reconstructed the HIV-1 packaging system in the context of a heterologous murine leukemia virus (MLV) vector RNA to elucidate a mechanism in which the Rev/RRE system is central to achieving efficient and specific encapsidation into HIV-1 viral particles. Results We show for the first time that the Rev/RRE system can augment RNA encapsidation independent of all cis elements from the 5' UTR (R, U5, PBS, and ψ). Incorporation of all the 5' UTR cis elements did not enhance RNA encapsidation in the absence of the Rev/RRE system. In fact, we demonstrate that the Rev/RRE system is required for specific and efficient encapsidation commonly associated with the canonical packaging signal. The mechanism of Rev/RRE-mediated encapsidation is not a general phenomenon, since the combination of the Rev/RRE system and 5' UTR cis elements did not enhance encapsidation into MLV-derived viral particles. Lastly, we show that heterologous MLV RNAs conform to transduction properties commonly associated with HIV-1 viral particles, including in vivo transduction of non-dividing cells (i.e. mouse neurons); however, the cDNA forms are episomes predominantly in the 1-LTR circle form. Conclusions Premised on encapsidation of a heterologous RNA into HIV-1 viral particles, our findings define a functional HIV-1 packaging system as comprising the 5' UTR cis elements, Gag, and the Rev/RRE system, in which the Rev/RRE system is required to make the RNA amenable to the ensuing interaction between Gag and the canonical packaging signal for subsequent encapsidation

Decolonizing Qualitative Instruments: Adapting Qualitative Instruments for Meaningful and Culturally Appropriate Data Collection in Schools with Indigenous Majority Populations

Files attached below (in order) are the paper "Decolonizing Qualitative Instruments: Adapting Qualitative Instruments for Meaningful and Culturally Appropriate Data Collection in Schools with Indigenous Majority Populations" and the presentation slides.Further information about the Instructional Practices Inventory may be found at http://education.missouri.edu/orgs/mllc/4A_ipi_overview.phpPresented at the National Middle School Association, Annual Convention, Houston, November 2007.The purpose of this research project is to explore decolonizing an observational assessment process and consider its utility for use in diverse school settings. To meet this research goal, the research team selected the Instructional Practices Inventory (IPI), a process for profiling student engaged learning for school improvement. The research team will examine: 1) the vocabulary used in the instrument, 2) the criteria used to classify observations, 3) the recommended procedures for facilitating faculty analysis and problem-solving, and 4) the utilization of cultural interpreters from the target populations

Insights into the mechanisms of HIV-1 cis elements and trans factors required for RNA encapsidation and transduction

The retroviral replication process is typically separated into early events of infection for the virus to enter a host cell, and late events that generate new viral particles. Encapsidation (late event) and early infection events are governed by several different cis elements located in the viral RNA, and viral, or cellular, trans factors (proteins). A number of viral encoded components have been identified to function in the encapsidation process, most notably the Gag polyprotein and genomic RNA cis elements in the 5' untranslated region (UTR). Although conventionally associated with nuclear export of HIV-1 RNA, there is also a burgeoning role for the Rev/RRE in the encapsidation process. Additionally, cis elements of the RNAs encapsidated into viral particles may influence different early stages of infection into host cells. This dissertation employs an innovative approach that affords separation of cis and trans viral components to investigate their independent, and combined, effects on encapsidation and early events of infection that will be referred to as transduction. HIV-1 cis elements were reconstructed in the context of heterologous RNAs to assess encapsidation and transduction functions. This work demonstrates for the first time that the Rev/RRE system can augment heterologous RNA encapsidation independent of all cis elements from the 5' UTR. In fact, the Rev/RRE system appears to be required for specific and efficient encapsidation into HIV-1 viral particles, a process more commonly associated with Gag recognition of the canonical packaging signal in the 5' UTR. Premised on encapsidation of a heterologous RNA into HIV-1 viral particles, our findings define a functional HIV-1 packaging system as comprising the 5' UTR cis elements, Gag, and the Rev/RRE system, in which the Rev/RRE system is required to make the RNA amenable to ensuing interactions between Gag and the canonical packaging signal for subsequent encapsidation. Lastly, we show that heterologous RNAs can conform to transduction properties commonly associated with HIV-1 viral particles. Furthermore, some heterologous RNAs exhibit an episomal profile in transduced cells that may have improved safety benefits over more conventional nonintegrating lentiviral vectors. These innovative vector systems may prove beneficial for therapeutic gene delivery to nondividing cells

Microscopic Structure of Liquid Nitric Oxide

The microscopic structure of nitric oxide is investigated using neutron scattering experiments. The measurements are performed at various temperatures between 120 and 144 K and at pressures between 1.1 and 9 bar. Using the technique of empirical potential structure refinement (EPSR), our results show that the dimer is the main form, around 80%, of nitric oxide in the liquid phase at 120 K, but the degree of dissociation to monomers increases with increasing temperature. The reported degree of dissociation of dimers, and its trend with increasing temperature, is consistent with earlier measurements and studies. It is also shown that nonplanar dimers are not inconsistent with the diffraction data and that the possibility of nitric oxide molecules forming longer oligomers, consisting of bonded nitrogen atoms along the backbone, cannot be ruled out in the liquid. A molecular dynamics simulation is used to compare the present EPSR simulations with an earlier proposed intermolecular potential for the liquid

An effective DNA vaccine platform for Middle East respiratory syndrome coronavirus

Middle East respiratory syndrome coronavirus (MERS-CoV) is an ongoing emerging infectious disease across the Arabian Peninsula, with the majority of cases occurring in Saudi Arabia. Through September 23, 2016 the World Health Organization reported about 1,806 total cases, including 643 deaths from 27 countries (http://www.who.int/emergencies/mers-cov/en/). The disease is comprised of a lower respiratory infection wherein individuals exhibit pneumonia-like symptoms that often lead to multi-organ failure and death (1). In addition to close contact with infected camels, transmission from human-to-human most commonly occurs in the hospital setting through close contact between patients and hospital workers (1). MERS-CoV has also been isolated from objects within patient rooms including bed sheets, bed rails, and IV fluid hangers (2), which may all be potential sources of transmission. Several cases of MERS-CoV have been associated with travelers returning home from the Middle East and developing symptoms, including two cases of health care workers returning to the United States (3). The potential for global spread was recently illustrated by a South Korean national returning home from visiting the Arabian Peninsula in May, 2015, and initiating an outbreak that infected 186 people resulting in 20% mortality and a nationwide economic crisis (4). Nonetheless, MERS-CoV is not thought to be sustained in the human population through human-to-human transmission, but may instead be continuously re-introduced into the human population from a zoonotic source, most likely dromedary camels because of high seropositive rates in herds throughout the Middle East (5,6). As camels are integral to the Saudi Arabian culture and economy, nationwide culling of camel herds is not feasible. Consequently, camel vaccination is being considered (7); however, therapeutic strategies have primarily focused on interfering with MERS-CoV infection in humans (3,5)

Glycosylation of Mouse DPP4 Plays a Role in Inhibiting Middle East Respiratory Syndrome Coronavirus Infection

Middle East respiratory syndrome coronavirus (MERS-CoV) utilizes dipeptidyl peptidase 4 (DPP4) as an entry receptor. Mouse DPP4 (mDPP4) does not support MERS-CoV entry; however, changes at positions 288 and 330 can confer permissivity. Position 330 changes the charge and glycosylation state of mDPP4. We show that glycosylation is a major factor impacting DPP4 receptor function. These results provide insight into DPP4 species-specific differences impacting MERS-CoV host range and may inform MERS-CoV mouse model development