Thermal Tolerance in Tropical Versus Subtropical Pacific Reef Corals

Upper lethal temperature tolerances of reef corals in Hawaii and at Enewetak, Marshall Islands, were determined in the field and under controlled laboratory conditions. Enewetak corals survived in situ temperatures of nearly 34° C, whereas 32° C was lethal to Hawaiian corals for similar short-term exposures. Laboratory determinations indicate that the upper thermal limits of Hawaiian corals are approximately 2° C less than congeners from the tropical Pacific. Differences in coral thermal tolerances correspond to differences in the ambient temperature patterns between geographic areas

Quantum-enhanced metrology with the single-mode coherent states of an optical cavity inside a quantum feedback loop

In this paper, we use the nonlinear generator of dynamics of the individual quantum trajectories of an optical cavity inside an instantaneous quantum feedback loop to measure the phase shift between two pathways of light with a precision above the standard quantum limit. The feedback laser provides a reference frame and constantly increases the dependence of the state of the resonator on the unknown phase. Since our quantum metrology scheme can be implemented with current technology and does not require highly efficient single photon detectors, it should be of practical interest until highly entangled many-photon states become more readily available

The Williams Scale of Attitude toward Paganism: development and application among British Pagans

This article builds on the tradition of attitudinal measures of religiosity established by Leslie Francis and colleagues with the Francis Scale of Attitude toward Christianity (and reflected in the Sahin-Francis Scale of Attitude toward Islam, the Katz-Francis Scale of Attitude toward Judaism, and the Santosh-Francis Scale of Attitude toward Hinduism) by introducing a new measure to assess the attitudinal disposition of Pagans. A battery of items was completed by 75 members of a Pagan Summer Camp. These items were reduced to produce a 21-item scale that measured aspects of Paganism concerned with: the God/Goddess, worshipping, prayer, and coven. The scale recorded an alpha coefficient of 0.93. Construct validity of the Williams Scale of Attitude toward Paganism was demonstrated by the clear association with measures of participation in private rituals

Leaving no-one behind? Social inequalities and contrasting development impacts in rural Rwanda

Two polar viewpoints have emerged regarding Rwanda’s post-genocide development: (1) that economic development has improved the wellbeing of Rwandans and (2) that repressive policies have negatively impacted many. Assessing the impacts and inclusiveness of policies through trends among different social groups is timely in the context of the Sustainable Development Goals’ pledge to ‘leave no-one behind’. This study examines rural Rwandans’ perspectives on the changes affecting them. A multidimensional wellbeing approach was applied through mixed-method research involving 115 rural households in two locations in western Rwanda, in 2011–12. Findings reveal that the household-level impact was heavily influenced by socio-economic power and socio-ethnic grouping. Negative impacts, including restricted freedom and loss of material and cultural resources are disproportionately felt by the poorest. The indigenous Batwa suffer particularly detrimental impacts. The findings suggest that strategies deemed successful in making progress towards the Millennium Development Goals in Rwanda need, as a minimal measure, to be supported by social protection programs that specifically target the landless, vulnerable and cultural minorities. However, to align Rwanda’s development policies with the ambitions of the Sustainable Development Goals (SDGs), a dramatic strategic shift is required to ‘leave no-one behind’ and avoid the reproduction of poverty and exacerbation of inequality

Hardware in the Loop Testing of an Iodine-Fed Hall Thruster

CUBESATS are relatively new spacecraft platforms that are typically deployed from a launch vehicle as a secondary payload,1 providing low-cost access to space for a wide range of end-users. These satellites are comprised of building blocks having dimensions of 10x10x10 cm cu and a mass of 1.33 kg (a 1-U size). While providing low-cost access to space, a major operational limitation is the lack of a propulsion system that can fit within a CubeSat and is capable of executing high delta v maneuvers. This makes it difficult to use CubeSats on missions requiring certain types of maneuvers (i.e. formation flying, spacecraft rendezvous). Recently, work has been performed investigating the use of iodine as a propellant for Hall-effect thrusters (HETs) 2 that could subsequently be used to provide a high specific impulse path to CubeSat propulsion. Iodine stores as a dense solid at very low pressures, making it acceptable as a propellant on a secondary payload. It has exceptionally high Isp (density times specific impulse), making it an enabling technology for small satellite near-term applications and providing the potential for systems-level advantages over mid-term high power electric propulsion options. Iodine flow can also be thermally regulated, subliming at relatively low temperature ( less than100 C) to yield I2 vapor at or below 50 torr. At low power, the measured performance of an iodine-fed HET is very similar to that of a state-of-the-art xenon-fed thruster. Just as importantly, the current-voltage discharge characteristics of low power iodine-fed and xenon-fed thrusters are remarkably similar, potentially reducing development and qualifications costs by making it possible to use an already-qualified xenon-HET PPU in an iodine-fed system. Finally, a cold surface can be installed in a vacuum test chamber on which expended iodine propellant can deposit. In addition, the temperature doesn't have to be extremely cold to maintain a low vapor pressure in the vacuum chamber (it is under 10(exp -6) torr at -75 C), making it possible to 'cryopump' the propellant with lower-cost recirculating refrigerant-based systems as opposed to using liquid nitrogen or low temperature gaseous helium cryopanels. In the present paper, we describe testing performed using an iodine-fed 200 W Hall thruster mounted to a thrust stand and operated in conjunction with MSFCs Small Projects Rapid Integration and Test Environment (SPRITE) Portable Hardware In the Loop (PHIL) hardware. This work is performed in support of the iodine satellite (iSAT) project, which aims to fly a 200-W iodine-fed thruster on a 12-U CubeSat. The SPRITE PHIL hardware allows a given vehicle to do a checkout of its avionics algorithm by allowing it to monitor and feed data to simulated sensors and effectors in a digital environment. These data are then used to determine the attitude of the vehicle and a separate computer is used to interpret the data set and visualize it using a 3D graphical interface. The PHIL hardware allows the testing of the vehicles bus by providing 'real' hardware interfaces (in the case of this test a real RS422 bus) and specific components can be modeled to show their interactions with the avionics algorithm (e.g. a thruster model). For the iSAT project the PHIL is used to visualize the operating cycle of the thruster and the subsequent effect this thrusting has on the attitude of the satellite over a given period of time. The test is controlled using software running on an Andrews Space Cortex 160 flight computer. This computer is the current baseline for a full iSAT mission. While the test could be conducted with a lab computer and software, the team chose to exercise the propulsion system with a representative CubeSat-class computer. For purposes of this test, the "flight" software monitored the propulsion and PPU systems, controlled operation of the thruster, and provided thruster state data to the PHIL simulation. Commands to operate the thruster were initiated from an operator's workstation outside the vacuum chamber and passed through the Cortex 160 to exercise portions of the flight avionics. Two custom-designed pieces of electronics hardware have been designed to operate the propellant feed system. One piece of hardware is an auxiliary board that controls a latch valve, proportional flow control valves (PFCVs) and valve heaters as well as measuring pressures, temperatures and PFCV feedback voltage. An onboard FPGA provides a serial link for issuing commands and manages all lower level input-output functions. The other piece of hardware is a power distribution board, which accepts a standard bus voltage input and converts this voltage into all the different current-voltage types required to operate the auxiliary board. These electronics boards are located in the vacuum chamber near the thruster, exposing this hardware to both the vacuum and plasma environments they would encounter during a mission, with these components communicating to the flight computer through an RS-422 interface. The auxiliary board FPGA provides a 28V MOSFET switch circuit with a 20ms pulse to open or close the iodine propellant feed system latch valve. The FPGA provides a pulse width modulation (PWM) signal to a DC/DC boost converter to produce the 12-120V needed for control of the proportional flow control valve. There are eight MOSFET-switched heating circuits in the system. Heaters are 28V and located in the latch valve, PFCV, propellant tank and propellant feed lines. Both the latch valve and PFCV have thermistors built into them for temperature monitoring. There are also seven resistance temperature device (RTD) circuits on the auxiliary board that can be used to measure the propellant tank and feedline temperatures. The signals are conditioned and sent to an analog to digital converter (ADC), which is directly commanded and controlled by the FPGA

Live to cheat another day: bacterial dormancy facilitates the social exploitation of beta-lactamases

The breakdown of antibiotics by β-lactamases may be cooperative, since resistant cells can detoxify their environment and facilitate the growth of susceptible neighbours. However, previous studies of this phenomenon have used artificial bacterial vectors or engineered bacteria to increase the secretion of β-lactamases from cells. Here, we investigated whether a broad-spectrum β-lactamase gene carried by a naturally occurring plasmid (pCT) is cooperative under a range of conditions. In ordinary batch culture on solid media, there was little or no evidence that resistant bacteria could protect susceptible cells from ampicillin, although resistant colonies could locally detoxify this growth medium. However, when susceptible cells were inoculated at high densities, late-appearing phenotypically susceptible bacteria grew in the vicinity of resistant colonies. We infer that persisters, cells that have survived antibiotics by undergoing a period of dormancy, founded these satellite colonies. The number of persister colonies was positively correlated with the density of resistant colonies and increased as antibiotic concentrations decreased. We argue that detoxification can be cooperative under a limited range of conditions: if the toxins are bacteriostatic rather than bacteridical; or if susceptible cells invade communities after resistant bacteria; or if dormancy allows susceptible cells to avoid bactericides. Resistance and tolerance were previously thought to be independent solutions for surviving antibiotics. Here, we show that these are interacting strategies: the presence of bacteria adopting one solution can have substantial effects on the fitness of their neighbours

The Vehicle, Fall 1982

Vol. 24, No. 1 Table of Contents Winter SurveillanceB.L. Davidsonpage 3 The InvitationBecky Lawsonpage 4 Check In, Check OutSteve Sandstrompage 4 On The Front Porch StepKeila Tooleypage 5 Old Greek ManDevon Flesorpage 5 Exotic PassionsBecky Lawsonpage 6 PhotographLisa Owenspage 7 Beyond The ThornsBrook Wilsonpage 8 Ritual Of HeatB.L. Davidsonpage 11 The GamerBecky Lawsonpage 12 It\u27s OverKeila Tooleypage 13 DreamJohn Stockmanpage 14 Silver DollarGina J. Grillopage 15 The DancerJessica Lewispage 16 Snapshots Of Rural IllinoisIsabel M. Parrottpage 16 The Last SeasonTheresa Whitesidepage 17 DrawingKaren Haneypage 17 Rotary LuncheonJessica Lewispage 18 Factory TourLinda Fraembspage 18 The ImmigrantsD.L. Lewispage 19 At Shedd AquariumLinda Fraembspage 20 The GuardianBecky Lewispage 20 Digital LifeEverett Tackettpage 21 Full ServiceScott Graypage 22 Dust ShowLinda A. Brownpage 23 At SixMaureen Foertschpage 24 DrawingJean Imherrpage 24 ReflectionMaggie Kennedypage 25 Cat DefiningBecky Lawsonpage 26 Ode To An Unread NewspaperLinda Fraembspage 26 GumSteve Sandstrompage 27 The DancerChrystal Clarkpage 27 PoemD.L. Lewispage 28 For LucyStacey Flanniganpage 29 An AbortionDevon Flesorpage 29 ReveriesKeila Tooleypage 30 Sunday Morning After Tequila With LemonScott Graypage 33 Staging A Living Jewel BoxMichelle Mitchellpage 34 The Other WomanStacey Flanniganpage 35 The Natural LookMichelle Mitchellpage 35 Poem To A Girl Named SandalsJohn Stockmanpage 36 PhotographLisa Owenspage 37 In The Balcony Of The Bijou On A Saturday NightScott Graypage 38 The Canadian Soccer PlayerBecky Lawsonpage 39 The HealingJohn Stockmanpage 39 AppeasedDevon Flesorpage 40 CodaJohn Stockmanpage 40https://thekeep.eiu.edu/vehicle/1040/thumbnail.jp

Ecological Invasion, Roughened Fronts, and a Competitor's Extreme Advance: Integrating Stochastic Spatial-Growth Models

Both community ecology and conservation biology seek further understanding of factors governing the advance of an invasive species. We model biological invasion as an individual-based, stochastic process on a two-dimensional landscape. An ecologically superior invader and a resident species compete for space preemptively. Our general model includes the basic contact process and a variant of the Eden model as special cases. We employ the concept of a "roughened" front to quantify effects of discreteness and stochasticity on invasion; we emphasize the probability distribution of the front-runner's relative position. That is, we analyze the location of the most advanced invader as the extreme deviation about the front's mean position. We find that a class of models with different assumptions about neighborhood interactions exhibit universal characteristics. That is, key features of the invasion dynamics span a class of models, independently of locally detailed demographic rules. Our results integrate theories of invasive spatial growth and generate novel hypotheses linking habitat or landscape size (length of the invading front) to invasion velocity, and to the relative position of the most advanced invader.Comment: The original publication is available at www.springerlink.com/content/8528v8563r7u2742