The surface of Mars 3. Light and dark markings

The Mariner 6 and 7 pictures have provided significant clues to the nature of the light and dark markings on Mars, but do not yet provide an adequate foundation for any complete explanation of the phenomena. They display detail never before seen or photographed and demonstrate that there is no network of dark lines (i.e. canals) on the planet. A variety of shapes and of boundaries between major markings are recorded in the pictures. No substantial correlation of albedo markings with cratered or chaotic terrain has been recognized; featureless terrain conceivably may be genetically related to light areas. Within and surrounding the dark area Meridiani Sinus there is evidence of local topographic control of albedo markings; light material is found in locally low areas. Also, characteristic patterns of local albedo markings are exhibited by craters there. Aeolian transportation of light material with deposition locally in low areas is suggested as an explanation of these markings and may be useful as a working hypothesis for subsequent exploration. Across some light/dark boundaries crater morphologies are unchanged; across others craters in the light area appear smoother. If there is a relationship between cratered terrain modification and surface albedo it is an indirect one

Mariner Mars 1969: Atmospheric results

Results of investigation of probable atmospheric effects appearing in Mariner '69 TV pictures that have undergone noise removal and preliminary decalibration are described. Two distinct types of haze are distinguished: north polar haze, seen prominently against the face of the planet in blue photographs, and thin haze, usually identified by its appearance on the limb and not strongly colored. Thin haze is surprisingly widespread, particularly in the southern hemisphere. Discrete bright features, which may be evidence for condensation on the ground or in the atmosphere, are described. These occur where bright features have often been seen from earth, in a region where very large multiple-ringed structures seem to dominate the surface morphology. The speculation that these may be evidence for local water-vapor exchange between ground and atmosphere is raised, and some constraints on local subsurface water-vapor sources in the Mars tropics are described. Finally, some implications of the Mariner '69 results for atmospheric exploration by Mariner '71 are briefly discussed

Estimating optimal operation time of korral kools on dairy cows in a desert environment

Dairy Research, 2008 is known as Dairy Day, 2008Developing management strategies for Korral Kools will help producers provide cooling in the housing area while minimizing the operational cost of the Korral Kools system. Two experiments were conducted at a dairy in Saudi Arabia to evaluate operational time of Korral Kools for multiparous and primiparous dairy cows. For multiparous cows, running time per day of Korral Kools should be continuous, but for primiparous cows, no difference in performance was detected between 21 and 24 hours. However, producers need to be careful when reducing daily operation time of Korral Kools for primiparous cows because elevated core body temperatures were observed in both treatments

Parents, children and the porous boundaries of the sexual family in law and popular culture

This article focuses on a perceived ideological overlap between popular cultural and judicial treatments of sex and conjugality that contributes to a discursive construction of parenthood and parenting. The author perceives that in both legal and popular cultural texts, there is a sense in which notions of ‘natural’ childhood are discursively constituted as being put at risk by those who reproduce outside of dominant sexual norms, and that signs of normative sexuality (typically in the form of heterosexual coupling) may be treated as a sign of safety. These ideas are rooted in ancient associations between fertility, sexuality and femininity that can also be traced in the historical development of the English language. With the help of commentators such as Martha Fineman, the article situates parents and children within a discourse of family which prioritises conjugality, with consequences for the ways in which the internal and external boundaries of families are delineated

Formation of the oxygen torus in the inner magnetosphere: Van Allen Probes observations

We study the formation process of an oxygen torus during the 12–15 November 2012 magnetic storm, using the magnetic field and plasma wave data obtained by Van Allen Probes. We estimate the local plasma mass density (ρL) and the local electron number density (neL) from the resonant frequencies of standing Alfvén waves and the upper hybrid resonance band. The average ion mass (M) can be calculated by M ∼ ρL/neL under the assumption of quasi-neutrality of plasma. During the storm recovery phase, both Probe A and Probe B observe the oxygen torus at L = 3.0–4.0 and L = 3.7–4.5, respectively, on the morning side. The oxygen torus has M = 4.5–8 amu and extends around the plasmapause that is identified at L∼3.2–3.9. We find that during the initial phase, M is 4–7 amu throughout the plasma trough and remains at ∼1 amu in the plasmasphere, implying that ionospheric O+ ions are supplied into the inner magnetosphere already in the initial phase of the magnetic storm. Numerical calculation under a decrease of the convection electric field reveals that some of thermal O+ ions distributed throughout the plasma trough are trapped within the expanded plasmasphere, whereas some of them drift around the plasmapause on the dawnside. This creates the oxygen torus spreading near the plasmapause, which is consistent with the Van Allen Probes observations. We conclude that the oxygen torus identified in this study favors the formation scenario of supplying O+ in the inner magnetosphere during the initial phase and subsequent drift during the recovery phase

NICMOS Imaging of the HR 4796A Circumstellar Disk

We report the first near infrared (NIR) imaging of a circumstellar annular disk around the young (~8 Myr), Vega-like star, HR 4796A. NICMOS coronagraph observations at 1.1 and 1.6 microns reveal a ring-like symmetrical structure peaking in reflected intensity 1.05 arcsec +/- 0.02 arcsec (~ 70 AU) from the central A0V star. The ring geometry, with an inclination of 73.1 deg +/- 1.2 deg and a major axis PA of 26.8 deg +/- 0.6 deg, is in good agreement with recent 12.5 and 20.8 micron observations of a truncated disk (Koerner, et al. 1998). The ring is resolved with a characteristic width of less than 0.26 arcsec (17 AU) and appears abruptly truncated at both the inner and outer edges. The region of the disk-plane inward of ~60 AU appears to be relatively free of scattering material. The integrated flux density of the part of the disk that is visible (greater than 0.65 arcsec from the star) is found to be 7.5 +/- 0.5 mJy and 7.4 +/- 1.2 mJy at 1.1 and 1.6 microns, respectively. Correcting for the unseen area of the ring yields total flux densities of 12.8 +/- 1.0 mJy and 12.5 +/- 2.0 mJy, respectively (Vega magnitudes = 12.92 /+- 0.08 and 12.35 +/-0.18). The NIR luminosity ratio is evaluated from these results and ground-based photometry of the star. At these wavelengths Ldisk(lambda)/L*(lambda) = 1.4 +/- 0.2E-3 and 2.4 +/- 0.5E-3, giving reasonable agreement between the stellar flux scattered in the NIR and that which is absorbed in the visible and re-radiated in the thermal infrared. The somewhat red reflectance of the disk at these wavelengths implies mean particle sizes in excess of several microns, larger than typical interstellar grains. The confinement of material to a relatively narrow annular zone implies dynamical constraints on the disk particles by one or more as yet unseen bodies.Comment: 14 pages, 1 figure for associated gif file see: http://nicmosis.as.arizona.edu:8000/AAS99/FIGURE1_HR4796A_ApJL.gif . Accepted 13 January 1999, Astrophyical Journal Letter

Using the ionospheric response to the solar eclipse on 20th March 2015 to detect spatial structure in the solar corona

Long-term variability has previously been observed in the relative magnitude of annual and semi-annual variations in the critical frequency (related to the peak electron concentration) of the ionospheric F2 layer (foF2). In this paper we investigate the global patterns in such variability by calculating the time varying power ratio of semi-annual to annual components seen in ionospheric foF2 data sequences from 77 ionospheric monitoring stations around the world. The temporal variation in power ratios observed at each station was then correlated with the same parameter calculated from similar epochs for the Slough/Chilton data set (for which there exists the longest continuous sequence of ionospheric data). This technique reveals strong regional variation in the data, which bears a striking similarity to the regional variation observed in long-term changes to the height of the ionospheric F2 layer. We argue that since both the height and peak density of the ionospheric F2 region are influenced by changes to thermospheric circulation and composition, the observed long-term and regional variability can be explained by such changes. In the absence of long-term measurements of thermospheric composition, detailed modelling work is required to investigate these processes

Excitation of EMIC waves detected by the Van Allen Probes on 28 April 2013

Abstract We report the wave observations, associated plasma measurements, and linear theory testing of electromagnetic ion cyclotron (EMIC) wave events observed by the Van Allen Probes on 28 April 2013. The wave events are detected in their generation regions as three individual events in two consecutive orbits of Van Allen Probe-A, while the other spacecraft, B, does not detect any significant EMIC wave activity during this period. Three overlapping H+ populations are observed around the plasmapause when the waves are excited. The difference between the observational EMIC wave growth parameter (Eh) and the theoretical EMIC instability parameter (Sh) is significantly raised, on average, to 0.10 ± 0.01, 0.15 ± 0.02, and 0.07 ± 0.02 during the three wave events, respectively. On Van Allen Probe-B, this difference never exceeds 0. Compared to linear theory (Eh\u3eSh), the waves are only excited for elevated thresholds