1,436 research outputs found
Exploratory information searching in the enterprise: a study of user satisfaction and task performance.
No prior research has been identified that investigates the causal factors for workplace exploratory search task performance. The impact of user, task, and environmental factors on user satisfaction and task performance was investigated through a mixed methods study with 26 experienced information professionals using enterprise search in an oil and gas enterprise. Some participants found 75% of high-value items, others found none, with an average of 27%. No association was found between self-reported search expertise and task performance, with a tendency for many participants to overestimate their search expertise. Successful searchers may have more accurate mental models of both search systems and the information space. Organizations may not have effective exploratory search task performance feedback loops, a lack of learning. This may be caused by management bias towards technology, not capability, a lack of systems thinking. Furthermore, organizations may not âknowâ they âdon't knowâ their true level of search expertise, a lack of knowing. A metamodel is presented identifying the causal factors for workplace exploratory search task performance. Semistructured qualitative interviews with search staff from the defense, pharmaceutical, and aerospace sectors indicates the potential transferability of the finding that organizations may not know their search expertise levels
Developing a model for e-prints and open access journal content in UK further and higher education
A study carried out for the UK Joint
Information Systems Committee examined models for the
provision of access to material in institutional and
subject-based archives and in open access journals. Their
relative merits were considered, addressing not only
technical concerns but also how e-print provision (by
authors) can be achieved â an essential factor for an
effective e-print delivery service (for users). A "harvesting" model is recommended, where the metadata of articles deposited in distributed archives are harvested, stored and enhanced by a national service. This model has major advantages over the alternatives of a national centralized service or a completely decentralized one. Options for the implementation of a service based on the harvesting model are presented
Concentrations, Trends, and AirâWater Exchange of PCBs and Organochlorine Pesticides Derived from Passive Samplers in Lake Superior in 2011
The largest fresh water body in North America, Lake Superior, has the potential to both accumulate and serve as a secondary source of persistent bioaccumulative toxins, such as polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs). Polyethylene passive samplers (PEs) were thus simultaneously deployed at 19 sites in surface water and near surface atmosphere across Lake Superior to determine air and water concentrations and airâwater gradients of 18 PCBs and 24 OCPs. PCBs in the air and water were characterized by penta- and hexachlorobiphenyls with distribution along the coast correlated with proximity to developed areas. Surface water and atmospheric concentrations were dominated by α-HCH (average 250 pg Lâ1 and 4.2 pg mâ3, respectively), followed by HCB (average 17 pg Lâ1 and 89 pg mâ3, respectively). Decreases in open lake concentrations of PCBs in water and air from spring to summer were consistent with ongoing volatilization from the surface layer as the main cause. Conversely, α-endosulfan was consistently deposited into the surface water of Lake Superior. Results indicated that PCBs were depleted in the surface mixed layer, implying a physical limit on evasive fluxes. This was corroborated with measurements from a vertical profile, displaying greater PCB concentrations at depth
Studies on the growth and compositional development of antlers in red deer (Cervus elaphus)
The experiments described in this thesis investigated nutritional
and physiological aspects of antler growth in red deer stags. The
initial experiment (Section 3) examined the effects of winter nutrition
on subsequent antler casting date and velvet antler weight. Mature stags
on two different farm types (hill country, Farm H and irrigated lowland,
Farm L) were offered three levels of winter nutrition, two levels of a
concentrate supplement (ad libitum pellets and 1/2 ad libitum pellets)
and a basal hay ration. On both properties liveweight gains occurred in
supplemented groups and liveweight losses in unsupplemented groups. At
antler casting there were significant differences in liveweight of
approximately 10 kg between fully supplemented and unsupplemented groups.
Realimentation of winter liveweight losses subsequently occurred so that
by the following rut the effects of winter undernutrition had been
eliminated. On Farm H poor winter nutrition (hay only) resulted in a
significant delay in casting date (13 days) and lower velvet antler
yields (0.24 kg), than in stags offered the ad libitum concentrate
ration. Stags on Farm H were 13 kg lighter at commencement of the trial
than at Farm L and the differences in treatment effects obtained between
farms may have been due to differences in body condition at commencement
of the trial.
An association was demonstrated between liveweight and date of
antler casting, with heavier stags casting earlier than lighter stags.
There was no effect of age of stag on casting date. Of the liveweights
recorded, liveweight prior to the rut showed the best relationship with
casting date, possibly because the seasonal nature of liveweight change
meant that a weight recorded at this time gave the best indicator of the
true frame size of a stag. Both age and liveweight significantly
affected velvet antler weight, with increases of velvet antler weight of
0.26 kg between 3 and 4-year-old stags and of 0.30 kg between 4 and
5-year-old stags at the same liveweight. Within an age group velvet
weight increased by 0.12 kg for each 10 kg increase in pre-rut
liveweight.
The experiments described in Section 4 comprised studies on antler
growth and composition. In order to obtain data on antler growth and
composition individual antlers were removed sequentially from mature red
deer stags between 28 and 112 days after casting of hard antlers.
Contralateral antlers were removed after stripping of velvet. Wide
variation occurred in antler casting date (53 days) compared to date of
velvet stripping (24 days). The duration of the period of antler growth
may therefore be governed more by date of casting than by date of velvet
stripping. Mean duration of the antler growth period was 164 days.
Growth in length of the antler appeared to follow a sigmoid curve.
However, between 28 and 112 days after casting, rates of elongation were
close to linear. Mean length of hard stripped antlers was 0.71 m and
between 28 to 112 days after casting mean rate of antler elongation was
0.62 cm/day. Over this period indivdual antlers increased in fresh
weight at a rate of 13.7 g/d, with heaviest weight recorded 112 days
after antler casting, at approximately 130% of final hard antler weight.
Between 28 and 91 days of growth, volume of blood in the antler increased
linearly at a rate of 194 ml/kg. Three phases of mineralization were
demonstrated in developing antlers. Tips of growing antlers were
cartilaginous and poorly mineralized. A zone of mineralization occurred
5.0 to 7.5 cm behind the antler tip which corresponded histologically to
the transition from mineralized cartilage to trabecular bone. The second
phase of mineralization occurred through continued accretion of
trabecular bone in the antler shaft. The third phase, described as
"terminal mineralization" in this study, appeared to be associated with a
rapid increase in density of cortical bone in the periphery of the antler
shaft. Terminal mineralization (between 91 and 112 days after casting of
hard antlers) coincided with the slowing of growth in length, a decrease
in relative blood volume in the antler and an increase in levels of
plasma testosterone. These events occurred close to the summer solstice.
At velvet stripping individual antlers had a mean weight of
1.12 kg and contained 81.1% dry matter (DM). Fat free organic matter
(FFOM) and ash concentration in DM were 36.6 and 60.0%, respectively.
Peak daily rates of FFOM and ash deposition occurred between 91 days and
112 days after casting, at rates of 1.4% of hard antler FFOM and 1.6% of
hard antler ash. For a stag producing 2.24 kg of hard antler mean rates
of FFOM and ash deposition over this period were 9.3 and 18.3 g/d,
respectively. On a whole antler basis calcium concentration in antler
ash remained constant, at around 35%. Therefore peak rate of antler
calcium deposition would be 6.4 g/d.
In the final experiment (Section 5) mature stags were offered a
maintenance ration of greenfeed oats during the period of peak calcium
requirement for antler growth and the kinetics of calcium metabolism were
examined using a radio-isotope (âŽâ”Ca). Rates of faecal endogenous loss
were low and at approximately 6.4 mg/kg BW per were half the estimated
requirements of ARC (1980) for sheep and cattle. Availability of calcium
from greenfeed oats was low (mean, 37%) and less than 30% of
total calcium requirements were derived from the diet. Poorly
mineralized skeletal bones indicated that the shortfall in antler calcium
was derived from the skeleton. In spite of a severely negative calcium
balance stags were capable of maintaining high and apparently normal
rates of antler calcium deposition (mean, 44 mg/kg BW per day). Antlers
appear to be acting as a sink with calcium being irreversibly deposited
in the antler and lost to the animal's body. On the assumption therefore
that antler calcium behaves like calcium lost during lactation a kinetic
model of calcium metabolism in the stag was developed
On the specifics of modelling of rotary forging processes
Rotary forging process, in spite of its various advantages, has still not reached industrial production scale owing to its complex nature. With the advent of sophisticated finite-element modelling capabilities, it is now possible to make rotary forging more predictable and optimise it for industrial production standards. However, modelling by nature involves a series of assumptions and simplifications that can help us make reasonable predictions. It is important to know the important factors that affect the results, and what compromises can be made, with a genuine understanding of what the compromises will result in. This paper reports some initial findings from our attempt towards robust modelling for the design of the rotary forging process. Herein, we have taken the simple case of rotary upsetting of cylinders using a custom-designed rotary forging machine and modelled it using commercial metal-forming software QForm
Concentrations, Trends, and Air-Water Exchange of PAHs and PBDEs Derived from Passive Samplers in Lake Superior in 2011
Polycyclic aromatic hydrocarbons (PAHs) and polybrominated diphenylethers (PBDEs) are both currently released into the environment from anthropogenic activity. Both are hence primarily associated with populated or industrial areas, although wildfires can be an important source of PAHs, too. Polyethylene passive samplers (PEs) were simultaneously deployed in surface water and near surface atmosphere to determine spatial trends and air-water gaseous exchange of 22 PAHs and 11 PBDEs at 19 sites across Lake Superior in 2011. Surface water and atmospheric PAH concentrations were greatest at urban sites (up to 65 ng L-1 and 140 ng m-3, respectively, averaged from June to October). Near populated regions, PAHs displayed net air-to-water deposition, but were near equilibrium off-shore. Retene, probably depositing following major wildfires in the region, dominated dissolved PAH concentrations at most Lake Superior sites. Atmospheric and dissolved PBDEs were greatest near urban and populated sites (up to 6.8 pg L-1 and 15 pg m-3, respectively, averaged from June to October), dominated by BDE-47. At most coastal sites, there was net gaseous deposition of BDE-47, with less brominated congeners contributing to Sault Ste. Marie and eastern open lake fluxes. Conversely, the central open lake and Eagle Harbor sites generally displayed volatilization of PBDEs into the atmosphere, mainly BDE-47
Using Knowledge Organization Systems to automatically detect forward-looking sentiment in company reports to infer social phenomena.
The study investigates whether existing Knowledge Organization Systems (KOS) for strong and hesitant forward-looking sentiment could be improved to detect social phenomena.Five judges identified examples of strong/hesitant forward-looking sentiment which were used to compare the KOS developed in the study, to existing models. The âcompositeâ KOS was subsequently applied to annual company reports to generate word frequency and biologically inspired diversity ratios. Critical Realism was used as a philosophy to interpret word patterns.Results indicate the composite KOS improved on existing models identified in the literature for strong forward-looking sentiment. In one company, a statistically significant association was found between increasing diversity of assertive forward-looking sentiment and subsequent declining relative business performance. This supported the Pollyanna effect: the social phenomena of over-positive business language in that company. Sharp increases in mentions of the âfutureâ and âlearningsâ was discovered in another company which may be explained by an industrial disaster and subsequent crisis management rhetoric, supporting Discourse of Renewal Theory.This study shows that improvements can be made to existing KOS used to detect forward-looking sentiment in reports. Adopting Critical Realism as a philosophy when analysing âbig dataâ may lead to improved theory generation and the potential for differentiating insights
Establishment and Growth of Legumes on Uncultivatable Hill Country in East Coast New Zealand
Steep, non-arable hill country is a significant feature of New Zealand farming (Sheath 2011) and large tracts of it have been improved by over-sowing grass and assorted clover species, particularly white clover (Trifolium repens L.). Numerous other legume species are available in New Zealand from similar environments overseas that may be more productive on some steep hill country. Plant breeders in New Zealand have also produced inter-specific hybrids (Williams et al. 2010) with potentially useful attributes. As part of a large project to increase pasture production on non-arable hills, a range of legume species were established at 2 sites in New Zealand in 2012. This paper reports results from the first spring and early summer following establishment
Spatial Distribution and Air-Water Exchange of Organic Flame Retardents in the Lower Great Lakes
Organic flame retardants (OFRs) such as polybrominated diphenyl ethers (PBDEs) and novel halogenated flame retardants (NHFRs) are ubiquitous, persistent, and bioaccumulative contaminants that have been used in consumer goods to slow combustion. In this study, polyethylene passive samplers (PEs) were deployed throughout the lower Great Lakes (Lake Erie and Lake Ontario) to measure OFRs in air and water, calculate airâwater exchange fluxes, and investigate spatial trends. Dissolved ÎŁ12BDE was greatest in Lake Ontario near Toronto (18 pg/L), whereas gaseous ÎŁ12BDE was greatest on the southern shoreline of Lake Erie (11 pg/m3). NHFRs were generally below detection limits. Airâwater exchange was dominated by absorption of BDEs 47 and 99, ranging from â964 pg/m2/day to â30 pg/m2/day. ÎŁ12BDE in air and water was significantly correlated with surrounding population density, suggesting that phased-out PBDEs continued to be emitted from population centers along the Great Lakes shoreline in 2012. Correlation with dissolved ÎŁ12BDE was strongest when considering population within 25 km while correlation with gaseous ÎŁ12BDE was strongest when using population within 3 km to the south of each site. Bayesian kriging was used to predict dissolved ÎŁ12BDE over the lakes, illustrating the utility of relatively highly spatially resolved measurements in identifying potential hot spots for future study
Concentrations of Polychlorinated Biphenyls (PCBâs), Chlorinated Pesticides, and Heavy Metals and Other Elements in Tissues of Belugas, Delphinapterus leucas, from Cook Inlet
Tissues from Cook Inlet beluga whales, Delphinapterus leucas, that were collected as part of the Alaska Marine Mammal Tissue Archival Project were analyzed for polychlorinated biphenyls (PCBâs), chlorinated pesticides, and heavy metals and other elements. Concentrations of total PCBâs (ÎŁPCBâs), total DDT (ÎŁDDT), chlordane compounds, hexachlorobenzene (HCB), dieldrin, mirex, toxaphene, and hexachlorocyclohexane (HCH) measured in Cook Inlet beluga blubber were compared with those reported for belugas from two Arctic Alaska locations (Point Hope and Point Lay), Greenland, Arctic Canada, and the highly contaminated stock from the St. Lawrence estuary in eastern Canada. The Arctic and Cook Inlet belugas had much lower concentrations (ÎŁPCBâs and ÎŁDDT were an order of magnitude lower) than those found in animals from the St. Lawrence estuary. The Cook Inlet belugas had the lowest concentrations of all (ÎŁPCBâs aver-aged 1.49 ± 0.70 and 0.79 ± 0.56 mg/kg wet mass, and ÎŁDDT averaged 1.35 ± 0.73 and 0.59 ± 0.45 mg/kg in males and females, respectively). Concentrations in the blubber of the Cook Inlet males were significantly lower than those found in the males of the Arctic Alaska belugas (ÎŁPCBâs and ÎŁDDT were about half). The lower levels in the Cook Inlet animals might be due to differences in contaminant sources, food web differences, or different age distributions among the animals sampled. Cook Inlet males had higher mean and median concentrations than did females, a result attributable to the transfer of these compounds from mother to calf during pregnancy and during lactation. Liver concentrations of cadmium and mercury were lower in the Cook Inlet belugas (most cadmium values were <1 mg/kg and mercury values were 0.704â11.42 mg/kg wet mass), but copper levels were significantly higher in the Cook Inlet animals (3.97â123.8 mg/kg wet mass) than in Arctic Alaska animals and similar to those reported for belugas from Hudson Bay. Although total mercury levels were the lowest in the Cook Inlet population, methylmercury concentrations were similar among all three groups of the Alaska animals examined (0.34â2.11 mg/kg wet mass). As has been reported for the Point Hope and Point Lay belugas, hepatic concentrations of silver were r
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