Effects of elevated concentrations of prostaglandin F₂α on early embryonic survival in cows supplemented with exogenous progestogen

An experiment was performed to determine the stage of embryonic development detrimentally affected by elevated prostaglandin F2α (PGF2α) in the presence or absence of luteal oxytocin. Ninety-one beef cows had their estrous cycles synchronized and were bred by natural service and artificial insemination (Day 0). Cows were randomly assigned to receive either 3 ml saline (CON), 15 mg PGF2α (PGF) or 15 mg PGF2α + lutectomy (P+L) administered i.m. at 8 h intervals on either Days 5-8, 10-13 or 15-18 (3 x 3 factorial). Lutectomies were performed by transrectal digital pressure before initiation of treatment on Day 5, 10 or 15 for Days 5-8, 10-13 and 15-18, respectively. All cows were fed 4 mg/d of melengesterol acetate (MGA) from two days prior to initiation of treatment until Day 30. Lutectomies were performed on nine CON cows to verify the ability of MGA to sustain pregnancy. Seven of these nine animals were diagnosed pregnant by transrectal ultrasonography at Day 30. All cows were bled by jugular venipuncture at 0600 and 2200 h of their respective treatments for determination of Progesterone (P4), estradiol-17β (E2), 13,14-dihydro-15- keto-PGF2α (PGFM). Additionally, cows were bled at 30 min following initiation of treatment for determination of oxytocin (OT) concentrations. Concentrations of P3 were reduced (p \u3c 0.05) in all cows administered PGF and P+L by 2200 h on the first day of treatment. Mean concentrations ,of PGFM were increased in cows administered PGF and P+L treatments (456 ± 35 398 ± 35 pg/ml, respectively; p \u3c 0.01) compared to CON cows (84 ± 58 pg/ml) regardless of daygroup. Mean concentrations of OT were significantly increased in cows administered PGF when compared to CON and P+L in the Day 5-8 (P \u3c .07) and in the Day 10-13 and 15-18 groups (P = .0001). Pregnancy rates were reduced (p = 0.03) in the PGF(5-8) group (3/13, 23%) compared to CON (5/7, 72%). Lutectomy tended to improve pregnancy rate in P+L(5- 8; 6/11, 55%) compared to PGF(5-8; p = 0.1). Pregnancy rates tended (p = 0.07) to increase across daygroups in the PGF treatment (3/13, 23%; 5/10, 50%; and 6/10, 60% for Days 5-8, 10-13 and 15-18, respectively). Pregnancy rates did not differ between CON, PGF and P+L groups for Days 10-13 and 15-18. In conclusion, the most susceptible period of embryonic growth to the negative effects of PGF2α appears to be during morula to blastocyst development. Removal of the luteal source of oxytocin diminishes the negative effects of PGF2α administration on the bovine embryo during early development, possibly through interruption of the luteal. oxytocin-uterine PGF2α feedback loop

Humanoid Robots: Useful or Useless?

The potential usefulness of a humanoid robot (Robothespian) was investigated by a group of six MSc students who chose to use this system for one of their oral assignments. A variety of methodologies were used by the student ranging from treating the Robothepsian mostly as a machine to an apparently fully interactive live conversation. The humanoid robot proved to be an interesting and stimulating approach but it did have problems with the user interface used (touch screen display) and that there was only one available

The Louisiana alternative Career Diploma as institutionalized cultural capital: high school principals\u27 perceptions of its value

In an effort to address dropout, the Louisiana state legislature mandated an initiative in 2009 which required all school districts to offer an alternative vocational high school diploma. Because this alternative diploma, known as the Career Diploma, is being implemented in all high schools throughout Louisiana, this research was designed to ascertain high school principals’ perceptions regarding the Career Diploma’s value. Participants were principals of traditional four-year high schools located within the state of Louisiana. A researcher-designed survey instrument was disseminated to 258 high school principals throughout the state. Findings of the data analysis indicated differences in perceptions of value among the four measured dimensions of value. Principals rated the Career Diploma to be valuable as a mitigator of socioeconomic consequences of not obtaining a standard high school diploma. Principals placed high value on the Career Diploma as a solution to underlying causes of student dropout. Additionally, participants asserted that the Career Diploma is valuable relative to other graduation options. However, participants indicated low perceptions of value concerning the Career Diploma’s symbolic value

Legal Rights of Transgender Students in Education

Nearly 150,000 school-aged teenagers in the United States identify as transgender, but the population continues to face harassment, bullying, and discrimination from their peers and educators. The most recent battles for bathroom access based on gender identity has led to significant policy debates nationally and statewide. It is critical for school leaders to promote an all-inclusive and safe school environment to help improve the academic experience for transgender students. The purpose of this paper is to outline the current anti-discrimination federal and state laws that protect against sex and gender identity harassment in school, including Title IX, Equal Access Act, the Family Educational Rights and Privacy Act (FERPA), and the First and Fourteenth Amendments of the U.S. Constitution. Additionally, court cases such as Whitaker v. Kenosha and G.G. v. Gloucester County School Board have helped to set the precedence for equal access to facilities in public schools. This paper will conclude with opportunities for school leaders to cultivate an institution that ensures the success of transgender students

Modernized eLoran: The Case for Completely Changing Chains, Rates, and Phase Codes

First deployed in the U.S. in 1957, Loran-C dominated radio-based navigation for many years. In 2000 the FAA began a significant recapitalization of Loran in the U.S.; the 2001 Volpe report on the vulnerability of the GPS reinforced the need for a revamped Loran. What emerged was an enhanced or evolved version, so called eLoran, aiming to achieve, for example, 10- 20 meter absolute positioning accuracy, RNP 0.3 mile required navigation performance, and stratum 1 time. After 10 years of development, in 2010, this U.S. e ffort was halted and the U.S. transmitters were silenced; since that time, eLoran is still being developed in Europe and deployed in Asia. Earlier this year U.S. Government interest in eLoran has again stirred (evidenced by a U.S. Army request for information and a U.S. Dept. of Transportation request for public comment); the rest of these initiated much conversation at the 2015 ION ITM. The prior U.S. (and continuing European) development of eLoran kept many of the 1950\u27s system design choices so as to be compatible with legacy Loran receivers. These include the pulse shape, groups, chains, rates, phase codes, emission delays, etc. Chosen to suit 1950\u27s technology, many of these restrictions are no longer necessary given the advances in transmitter and receiver technology (e.g. software defined radio) over the last half century. It is the opinion of these authors that as Loran, per se, no longer exists in the U.S., any re-emergence of a low frequency radio navigation system need not be held to these performance limiting constraints. In prior work these authors have promoted more significant changes to eLoran to improve system performance; specifically, single-rating all stations, reconquering the chain/rate structure within the continental U.S., and changing the phase codes. The current paper expands on these prior e fforts. Specifically, we propose putting all of the eLoran transmitters on the same repetition period and employing unique phase codes for each transmitter. To effectively choose new phase codes for eLoran, and assess their performance, we rely on the auto- and cross-correlation metrics. These metrics describe how well a receiver can both acquire and track a specific signal when contaminated by multi- path interference, the existence of other signals, and noise. While a perfect auto-correlation function, large at zero lag corresponding to the actual arrival of the signal and zero elsewhere, and a perfect cross- correlation function, zero for all lags, are preferred, it is impossible to find such codes. However, limiting the size of the window for which we require perfect auto- and cross-correlations, such codes can be found. To create such codes for eLoran we adapt results from the CDMA literature on complementary sequences and Large Area Synchronized (LAS) codes. This paper begins with a brief review of the relevant characteristics of Loran-C, including a discussion of the effects of sky wave and cross rate interference. This is followed by a survey of previously published ideas/concepts on how elements of the system could be changed so as to improve performance. Finally, details on the proposed rate/chain/phase code structure are presented. The reader should recognize that these ideas and results are not intended to define what the best eLoran system would be; rather, if eLoran soars again in the U.S., we hope to initiate a dialogue that looks beyond the decisions made in the 1950\u27s

Incidence and correlates of violence among HIV-infected women at risk for pregnancy in the southeastern United States

To identify the incidence and correlates of physical and sexual violence among HIV-infected women at risk for pregnancy, a cross-sectional examination was conducted within a longitudinal study of reproductive decision making. Participants consisted of 275 HIVinfected women 17 to 49 years of age (mean = 30.1 years).Women were predominantly African American (87%) and single (82%), with annual incomes of $10,000 or less (66%). Overall, 68% of the women reported experiencing lifetime physical and/or sexual violence. Before becoming HIV infected, 65% of the women reported having been physically or sexually abused. After HIV diagnosis, 33% of the women reported experiencing physical or sexual abuse. Women reporting greater violence were more likely to disclose their HIV-seropositive status to their sex partner. Using logistic regression, greater intent to get pregnant (odds ratio [OR] = 0.933), decreased present life satisfaction (OR = 1.048), having three or more children (OR = 0.474), and history of drug use (OR = 0.794) significantly distinguished between women who reported physical and/or sexual violence and those who did not

Multi-Constellation GNSS: New Bounds on DOP and a Related Satellite Selection Process

GPS receivers convert the measured pseudoranges from the visible GPS satellites into an estimate of the position and clock offset of the receiver. For various reasons receivers might only track and process a subset of the visible satellites. It would be desired, of course, to use the best subset. In general selecting the best subset is a combinatorics problem; selecting m objects from a choice of n allows for n m potential subsets. And since the GDOP performance criterion is nonlinear and non-separable, finding the best subset is a brute force procedure; hence, a number of authors have described sub-optimal algorithms for choosing satellites. This paper revisits this problem, especially in the context of multiple GNSS constellations, for the GDOP and PDOP criteria. Included are a discussion of optimum constellations (based upon parallel work of these authors on achievable lower bounds to GDOP and PDOP), musings on how the non-separableness of DOP makes it impossible to rank order the satellites, and a review/discussion of subset selection algorithms. Our long term goal is the development of better selection algorithms for multi-constellation GNSS

Rethinking Star Selection in Celestial Navigation

In celestial navigation the altitude (elevation) angles to multiple celestial bodies are measured; these measurements are then used to compute the position of the user on the surface of the Earth. Methods described in the literature include the classical “altitude-intercept” algorithm as well as direct and iterative least-squares solutions for over determined situations. While it seems rather obvious that the user should select bright stars scattered across the sky, there appears to be no established results on the level of performance that is achievable based upon the number of stars sighted nor how the “best” set of stars might be selected from those visible. This paper addresses both of these issues by examining the performance of celestial navigation noting its similarity to the performance of GNSS systems; specifically, modern results on GDOP for GNSS are adapted to this classical celestial navigation problem

Using Range Information to Detect Spoofing in Platoons of Vehicles

GNSS are well known to be accurate providers of position information across the globe. Because of high signal availabilities, capable/robust receivers, and well-populated satellite constellations, operators typically believe that the location information provided by their GNSS receiver is correct. More sophisticated users are concerned with the integrity of the derived location information. Attacks on GNSS availability and integrity are known as jamming and spoofing. Jamming involves the transmission of signals that interfere with GNSS reception so that the receiver is unable to provide a position or time solution; various methods to detect jamming, and possibly overcome it, have been considered in the literature. Spoofing is the transmission of counterfeit GNSS signals so as to mislead a GNSS receiver into reporting an inaccurate position or time. If undetected, spoofing might be much more dangerous than a jamming attack. A variety of approaches have been proposed in the literature to recognize spoofing. Of interest here are methods which compare GNSS information to measurements available from other, non-GNSS sensors. Recent ION conferences have included several examinations of combining GNSS and non-GNSS data toward spoof detection. This paper considers the use of range-only information to detect GNSS spoofing of a platoon of vehicles equipped with inter-vehicle communications: a statistical model of the problem is developed in which the spoofer is assumed to have limited geographical impact (i.e. only spoofs a subset, nominally one, of the vehicles in the platoon); under a Neyman-Pearson formulation the (generalized) likelihood ratio test to fuse the GNSS and range measurements is presented; examples are included to demonstrate the resulting performance

The Use of Bearing Measurements for Detecting GNSS Spoofing

GNSS are well known to be accurate providers of position information across the globe. Because of high signal availabilities, robust receivers, and well-populated constellations, operators typically believe that the location information provided by their GNSS receiver is correct. More sophisticated users are concerned with the integrity of the derived location information; for example, employ RAIM algorithms to address possible satellite failure modes. The most common attacks on GNSS availability and integrity are known as jamming and spoofing. Jamming involves the transmission of signals that interfere with GNSS reception so that the receiver is unable to provide a position or time solution. Various methods to detect jamming, and possibly overcome it, have been considered in the literature. Spoofing is the transmission of counterfeit GNSS signals so as to mislead a GNSS receiver into reporting an inaccurate position or time. If undetected, spoofing might be much more dangerous than a jamming attack. A typical maritime concern is a spoofer convincing a tanker traveling up a channel to a harbor that it is off track of the channel. A variety of approaches have been proposed in the literature to recognize spoofing; many of these are based on the RF signal alone as, in some sense, they are the simplest to implement. Of interest here are methods which compare GNSS information to measurements available from other, non-GNSS sensors. Examined examples include IMUs, radars, and ranges/pseudoranges from non-GNSS signals. In all cases the data from these others sensors is compared to the position information from the GNSS receiver to assess its integrity. Triangulation of position from bearing measurements is a well-known localization technique, especially for the mariner. This paper considers the use of bearing information to detect GNSS spoofing in a 2-D environment. A typical marine application is a ship entering a harbor and using an alidade to sight landmarks; for mobile, autonomous vehicles the sensor might be a camera taking a bearing to a nearby vehicle or to a signpost. This paper presents a mathematical formulation of the problem and the sensor data, develops a statistical model of the measurements relative to the GNSS position output, constructs a generalized likelihood ratio test detection algorithm based on the Neyman-Pearson performance criterion (maximizing probability of detection while bounding the probability of false alarm), and examines performance of the test, both through analysis and experimentation. A comparison to using both range and bearing is included to show the utility and limitations of bearing data to spoof detection