Relative pointing offset analysis of calibration targets with repeated observations with Herschel-SPIRE Fourier-transform spectrometer

We present a method to derive the relative pointing offsets for SPIRE Fourier-Transform Spectrometer (FTS) solar system object (SSO) calibration targets, which were observed regularly throughout the Herschel mission. We construct ratios R _obs(ν) of the spectra for all observations of a given source with respect to a reference. The reference observation is selected iteratively to be the one with the highest observed continuum. Assuming that any pointing offset leads to an overall shift of the continuum level, then these R _obs(ν) represent the relative flux loss due to mispointing. The mispointing effects are more pronounced for a smaller beam, so we consider only the FTS short wavelength array (SSW, 958–1546 GHz) to derive a pointing correction. We obtain the relative pointing offset by comparing R _obs(ν) to a grid of expected losses for a model source at different distances from the centre of the beam, under the assumption that the SSW FTS beam can be well approximated by a Gaussian. In order to avoid dependency on the point source flux conversion, which uses a particular observation of Uranus, we use extended source flux calibrated spectra to construct R _obs(ν) for the SSOs. In order to account for continuum variability, due to the changing distance from the Herschel telescope, the SSO ratios are normalised by the expected model ratios for the corresponding observing epoch. We confirm the accuracy of the derived pointing offset by comparing the results with a number of control observations, where the actual pointing of Herschel is known with good precision. Using the method we derived pointing offsets for repeated observations of Uranus (including observations centred on off-axis detectors), Neptune, Ceres and NGC 7027. The results are used to validate and improve the point-source flux calibration of the FTS.     

Partial substitution of peat moss with biochar for sustainable cultivation of <Emphasis Type="Italic">Durio zibethinus L</Emphasis>. in nurseries

The extensive use of peat moss as potting medium in nurseries worldwide is not sustainable causing peatland depletion and greenhouse gas emissions. This research seeks to explore whether wood biochar produced by the environment-friendly flame curtain method can partially substitute peat moss in plant nurseries without affecting plant growth and health. Biochar was produced from durian wood logs in a top-quenched Kon-Tiki earth kiln, crushed, and mixed with peat moss at dosages of 0, 1, 2.5 and 5% (w/w). Durian seedlings were grown in 2.5 L polybags arranged in randomised complete block design with 4 replicates per treatment. Plant height, collar diameter, pH, moisture content, number of branches and leaves, and plant health were monitored weekly for 94 days. Liquid fish fertiliser was used as organic fertiliser. Our results demonstrated that biochar can substitute at least 5% (w/w) peat moss without negatively affecting plant height, collar diameter, number of leaves and branches, and plant health. In addition, organic fertiliser is not required during the first 3 months of cultivation resulting in cost savings to the nursery operator. Plant height was found to be the most accurate yet simple monitoring parameter studied. A better understanding of the effect of higher biochar application rates as well as the number of times the potting medium can be reused without loss of potting medium properties and health can help to further cut nursery cost and reduce reliance on peat moss.     

How Collaborative Governance Practitioners Can Assess the Effectiveness of Collaborative Environmental Governance,While Also Evaluating Their Own Services

Abstract

Collaborative governance applied to environmental issues is becoming more common, and evaluation of such efforts can provide useful information for multiple audiences. However, due to a variety of challenges, collaborative governance practitioners rarely evaluate the outcomes of collaboration and their contributions to these efforts. With these challenges in mind, the William D. Ruckelshaus Center designed an evaluation framework that can meet multiple parties’ objectives, be integrated into practitioners’ existing services, and balance flexibility and practicality with rigor and replicability. The Center conducted a pilot of this framework on a collaborative watershed management effort in southeastern Washington State, where the Center had previously assisted with organizational development. The resulting evaluation highlights a variety of social, knowledge-based, and economic outcomes for the collaborative, as well as lessons for practitioners and evaluators of collaborative governance. We suggest that this methodology can be useful for practitioners interested in evaluating similar collaborative efforts.     

Biology of evechinus chloroticus (Echinoidia: Echinometridae) from different localities

Growth bands were demonstrated in the apical plates of Evechinus chloroticus by grinding horizontal sections which were air dried for several days and treated with lactophenol + 0.5% ferrous ions for a few minutes. Only one dark band was formed each year, during summer.

Evechinus grew considerably faster at Kaikoura than at Kaiteriteri, about 2 cm and 1 cm a year respectively, until growth slowed with increasing age. These differences may relate to food availability.

Numbers in year classes varied considerably, and in some Evechinus populations year classes were absent. Most urchins at Kaiteriteri were less than 6 + years old, but urchins up to 10 years old were aged at Kaikoura. More old urchins were found in deeper populations at Kaikoura, where a number may have been up to 15 years old.

Size‐frequency distributions varied markedly among populations. Distributions appear most influenced by recruitment intensity, and higher growth rates and greater longevity were found in populations with predominantly large urchins, as at Kaikoura.     

Mid-Mountain Clouds at Whistler During the Vancouver 2010 Winter Olympics and Paralympics

A comprehensive study of mid-mountain clouds and their impacts on the Vancouver 2010 Winter Olympics and Paralympics is presented. Mid-mountain clouds were frequently present on the Whistler alpine venue, as identified in an extensive archive of webcam images over a 45-day period from February 5 to March 21, 2010. These clouds posed serious forecast challenges and had significant impacts on some Olympic and Paralympic alpine skiing competitions. Under fair weather conditions, a diurnal upslope (anabatic) flow can work in concert with a diurnal temperature inversion aloft to produce a localized phenomenon known as “Harvey’s Cloud” at Whistler. Two detailed case studies in this paper suggest that mid-mountain clouds can also develop in the area as a result of a moist valley flow interacting with a downslope flow descending from the mountaintop. A southerly inflow through the Sea-to-Sky corridor can be channeled by the local topography into a westerly upslope flow toward Whistler Mountain, resulting in orographic clouds on the alpine venue. Under favorable circumstances, these clouds are trapped to the mid-mountain zone by the leeward subsidence of an elevated southerly flow. The presence of the downslope subsidence was manifested by a distinguished dry layer observed on the top of the mid-mountain clouds in both cases. It is the subsidence-induced adiabatic warming that imposes a strong buoyant suppression to trap the mid-mountain cloud. On the other hand, the subsidence-induced dry layer has the potential to trigger evaporative instability to periodically breakup the mid-mountain cloud.     

A statistically selected Chandra sample of 20 galaxy clusters – II. Gas properties and cool core/non-cool core bimodality

We investigate the thermodynamic and chemical structure of the intracluster medium (ICM) across a statistical sample of 20 galaxy clusters analysed with the Chandra X-ray satellite. In particular, we focus on the scaling properties of the gas density, metallicity and entropy and the comparison between clusters with and without cool cores (CCs). We find marked differences between the two categories except for the gas metallicity, which declines strongly with radius for all clusters  ( Z ∝ r ^−0.31)  , outside  ∼0.02 r ₅₀₀  . The scaling of gas entropy is non-self-similar and we find clear evidence of bimodality in the distribution of logarithmic slopes of the entropy profiles. With only one exception, the steeper sloped entropy profiles are found in CC clusters whereas the flatter slope population are all non-CC clusters. We explore the role of thermal conduction in stabilizing the ICM and conclude that this mechanism alone is sufficient to balance cooling in non-CC clusters. However, CC clusters appear to form a distinct population in which heating from feedback is required in addition to conduction. Under the assumption that non-CC clusters are thermally stabilized by conduction alone, we find the distribution of Spitzer conduction suppression factors, f _c, to be lognormal, with a log (base 10) mean of  −1.50 ± 0.03  (i.e.   f _c= 0.032  ) and log standard deviation  0.39 ± 0.02  .     

The anatomy of the NGC 5044 group – II. Stellar populations and star formation histories

The distribution of galaxy properties in groups and clusters holds important information on galaxy evolution and growth of structure in the Universe. While clusters have received appreciable attention in this regard, the role of groups as fundamental to formation of the present-day galaxy population has remained relatively unaddressed. Here, we present stellar ages, metallicities and α-element abundances derived using Lick indices for 67 spectroscopically confirmed members of the NGC 5044 galaxy group with the aim of shedding light on galaxy evolution in the context of the group environment.
We find that galaxies in the NGC 5044 group show evidence for a strong relationship between stellar mass and metallicity, consistent with their counterparts in both higher and lower mass groups and clusters. Galaxies show no clear trend of age or α-element abundance with mass, but these data form a tight sequence when fitted simultaneously in age, metallicity and stellar mass. In the context of the group environment, our data support the tidal disruption of low-mass galaxies at small group-centric radii, as evident from an apparent lack of galaxies below  ∼10⁹ M_⊙  within ∼100 kpc of the brightest group galaxy. Using a joint analysis of absorption- and emission-line metallicities, we are able to show that the star-forming galaxy population in the NGC 5044 group appears to require gas removal to explain the ∼1.5 dex offset between absorption- and emission-line metallicities observed in some cases. A comparison with other stellar population properties suggests that this gas removal is dominated by galaxy interactions with the hot intragroup medium.     

Discarded containers on a kent beach

Winter beach surveys of discarded containers at Sandwich Bay showed a wide range of fabrication materials and contents. These were manufactured world-wide and probably distributed by seaborne disposal from local shipping. Although blow moulded polyethylene bottles containing toilet cleansers were commonly observed, there was no evidence to indicate an accumulation of these items in the marine environment.