2,246 research outputs found
Cocoon viability and evidence for delayed hatching by the earthworm Lumbricus terrestris in a laboratory-based study.
Clitellate Lumbricus terrestris, obtained from 5 commercial suppliers (A-E) and also field collected (F) - grassland in Preston, Lancashire, UK, were kept under controlled environmental conditions (15 °C and 24 h darkness) in a sterilised loam soil and surface-fed with horse manure. Survival, biomass and cocoon production was monitored every 4 weeks over 1 y. Collected cocoons were maintained in water-filled Petri dishes on filter paper. Time to hatch and cocoon viability was recorded over a 2 y period. Cocoon production ranged from 15.1 â 32.2 ind.-1 y-1. Cocoon production was initially low followed by a period of high production (12-36 weeks) and then fell (36-52 weeks). Time for cocoon hatching ranged from 132-731 days. Hatching success after 2 years was 58â90% across treatments, with a total viability (including cocoons dissected after the 2 year period) of 88-94%. Evidence of 2 distinct hatching peaks was recorded, separated by a period of approximately 12 months in treatments of most of the commercially obtained earthworms. Cocoon incubation periods are in excess of those previously recorded under similar laboratory conditions (e.g. 90â280 days). Furthermore, viability is also higher than previously recorded (e.g. 67.9â83%). These differences are mainly attributable to the extended length of cocoon observation. Origin, age, unknown pre-treatment (in A-E) and experimental conditions (e.g. a constant temperature regime) may have influenced incubation times. However, it is suggested that asynchronous and delayed hatching within cohorts and ability for cocoons to remain viable for extended periods allows this K-selected species to maximise reproductive potential. This proposed âbet-hedgingâ strategy is worthy of further laboratory and field-based investigation
Content-driven superpixels and their applications
This thesis develops a new superpixel algorithm that displays excellent visual reconstruction of the original image. It achieves high stability across multiple random initialisations, achieved by producing superpixels directly corresponding to local image complexity. This is achieved by growing superpixels and dividing them on image variation. The existing analysis was not sufficient to take these properties into account so new measures of oversegmentation provide new insight into the optimum superpixel representation. As a consequence of the algorithm, it was discovered that CDS has properties that have eluded previous attempts, such as initialisation invariance and stability. The completely unsupervised nature of CDS makes them highly suitable for tasks such as application to a database containing images of unknown complexity. These new superpixel properties have allowed new applications for superpixel pre-processing to be produced. These are image segmentation; image compression; scene classification; and focus detection. In addition, a new method of objectively analysing regions of focus has been developed using Light-Field photography
An oasis of fertility on a barren island: Earthworms at Papadil, Isle of Rum
The Isle of Rum, Inner Hebrides, has an impoverished earthworm fauna as the soils are generally acidic and nutrient-poor. Species associated with human habitation are found around deserted crofting settlements subjected to âclearancesâ in the mid-19th century and at Kinloch, where a large volume of fertile soil was imported from the mainland around 1900. Earthworms, and the dew worm Lumbricus terrestris L. in particular, were investigated at Papadil, an abandoned settlement and one of the few locations on Rum where a naturally developed brown earth soil is present. The small (1.5 ha), fertile location is isolated, so was also suitable for field experimentation. Visits over six years allowed dew worm distribution to be assessed within low lying grassland and woodland and also within an adjacent sloping broadleaved woodland. The factors limiting dew worm distribution at the site were investigated with associated translocation to adjacent uninhabited areas. Small scale spatial dynamics were studied with density manipulation and containment experiments where Visual Implant Elastomer marking of individuals was utilised. Translocations from streamside woodland to adjacent grassland was successful over a short period (5 months), but the colonies did not persist over a longer term (5-6 years). Field trials with earthworm tagging were successful, but highest tag recovery rate was 25%. Where adults/sub-adults were removed, recruitment of juveniles was notable. Exceptionally large (>12 g live mass) individuals were found in soils of terraces on wooded slopes, suggesting that dew worms may be long lived at this location, where food is abundant and relatively few terrestrial predators are present
United States Trade Flows for Selected Categories of Specialty Crops
Nationally, Florida ranked second in farm cash receipt from all crops and second, based on value, in vegetable production (USDA, 2003). It also ranked fourteenth out of all the states with respect to agricultural exports with its top exports, fruits and vegetables, falling within the category of specialty crops. According to the USDA (2003), Florida's agricultural exports helped to boost farm prices and income and supported approximately 17,000 jobs both on and off farm in 2001. As such, its agricultural exports are important to Florida's agricultural and statewide economy. From a Florida farm cash receipts perspective, increased imports could undermine revenue earnings from specialty crop production, especially if there is not a comparable growth in the exports of these crops. This report covered the period 1991 to 2002 and examined trade flows for selected specialty crops deemed important to Florida's agriculture. Overall, the US had a relatively high import level of the selected specialty crops. This was apparent from the widening trade gaps and the declining surpluses experienced by all commodities, with the exception of oranges and strawberries. CANMEX was the dominant supplier of vegetables, and growing imports from this group drove the growing vegetable trade deficit. With respect to fruits, CANMEX was also a dominant supplier and affected trade balances however, many of the declining fruit trade balances were due to declining exports to markets such as Asia and the Europe. CANMEX played a major role in the trade of foliage and floriculture but did not dominate the trade. Over the period 1991 to 2002 there were changes in the trade flows of the selected vegetables, fruits and foliage and floriculture. Two noticeable trends were the concentration of trade with CANMEX, especially with respect to vegetable exports and declining exports to Asia and Europe. Also noticeable were declining trade balances experienced by the majority of the commodities in this study. With free trade agreements, an increased inflow of goods is expected as trade barriers are lowered. Preparing for additional imports resulting from expanded regional free trade agreements in the western hemisphere requires the commitment of additional resources toward the expansion of existing markets and the development of potentially new markets.Crop Production/Industries, International Relations/Trade,
United States Trade Flows for Selected Categories of Specialty Crops and the General Policy Implication
International Relations/Trade,
Face-to-face and online collaboration: appreciating rules and adding complexity
This paper reports how 6-8 year-old children build, play and share video-games in an animated programming environment. Children program their games using rules as creative tools in the construction process. While working both face-to-face and remotely on their games, we describe how they can collaboratively come to explain phenomena arising from programmed or 'system' rules. Focusing on one illustrative case study of two children, we propose two conjectures. First, we claim that in face-to-face collaboration, the children centre their attention on narrative, and address the problem of translating the narrative into system rules which can be =programmedâ into the computer. This allowed the children to debug any conflicts between system rules in order to maintain the flow of the game narrative. A second conjecture is that over the Internet children were encouraged to add complexity and innovative elements to their games, not by the addition of socially-constructed or 'player' rules but rather through additional system rules which elaborate the mini-formalism in which they engaged. This shift of attention to system rules occurred at the same time, and perhaps as a result of, a loosening of the game narrative that was a consequence of the remoteness of the interaction
SODAS: Surveillance of Drugs of Abuse Study
Objective: Novel Psychoactive Substance (NPS) as a form of recreational drug use has become increasingly popular. There is a paucity of information with regards the prevalence and clinical sequalae of these drugs. The aim of this study was to detect NPS in patients presenting to the Emergency Department (ED) with suspected toxicological ingestion.
Methods: The prospective study was performed in a large Emergency Department (ED) in the UK. During a three month period eighty patients were identified by clinicians as having potentially ingested a toxicological agent. Urine sample were analysed using liquid chromatography-high resolution mass spectrometry and basic clinical data was gathered.
Results: 80 patients with a history of illicit or recreational drug consumption had urine screenings performed. 49% (39) of patients undergoing a screen had more than one illicit substance detected. 20% (16) of patients tested positive for at least one NPS.
Conclusions:
Almost half of patients presenting had ingestion of multiple substances which correlated poorly with self reporting of patients. Developing enhanced strategies to monitor evolving drug trends is crucial to the ability of clinicians to deliver care to this challenging group of patients
Type 1 diabetes and physical activity: An assessment of knowledge and needs in healthcare practitioners
This study examined healthcare practitionersâ knowledge and confidence in providing physical activity guidance to people with type 1 diabetes. Data collection occurred in the form of a 23-question, open-ended survey and semi-structured interviews exploring practitionersâ knowledge regarding exercise and type 1 diabetes. Participants had rarely received formal training regarding physical activity for people with type 1 diabetes. They indicated limited knowledge of specific physical activity guidelines, either for the general population or for people with type 1 diabetes. However, participants reported feeling relatively confident in their ability to advise people with type 1 diabetes regarding physical activity. The disparity between practitionersâ knowledge and confidence in advising people with type 1 diabetes about physical activity raises concerns regarding the accuracy of the information being provided to individuals with the condition
Analysis and clinical findings of cases positive for the novel synthetic cannabinoid receptor agonist MDMB-CHMICA
Context: MDMB-CHMICA is a synthetic cannabinoid receptor agonist which has caused concern due to its presence in cases of adverse reaction and death. Method: 43 cases of suspected synthetic cannabinoid ingestion were identified from patients presenting at an Emergency Department and from post-mortem casework. These were subjected to liquid-liquid extraction using tertiary-butyl methyl ether and quantitatively analysed by Electospray Ionisation Liquid Chromatography â tandem Mass Spectrometry. For positive samples, case and clinical details were sought and interrogated. Results: 11 samples were found positive for MDMB-CHMICA. Concentrations found ranged from <1 â 22 ng/mL (mean: 6 ng/mL, median: 3 ng/mL). The age range was 15 â 44 years (mean: 26 years, median: 21 years), with the majority (82%) of positive results found in males. Clinical presentations included hypothermia, hypoglycaemia, syncope, recurrent vomiting, altered mental state and serotonin toxicity, with corresponding concentrations of MDMB-CHMICA as low as <1 ng/mL. Duration of hospitalisation ranged from 3 â 24 hours (mean: 12 hours, median: 8 hours). Discussion: The concentration range presented in this case series is indicative of MDMB-CHMICA having a high potency, as is known to be the case for other synthetic cannabinoid receptor agonists. The age range and gender representation were consistent with that reported for users of other drugs of this type. The clinical presentations observed were typical of synthetic cannabinoid receptor agonists and show the difficulties in identifying reactions potentially associated with drugs of this type. Conclusion: The range of MDMB-CHMICA concentrations in Emergency Department presentations (n=9) and post-mortem cases (n=2) was reported. No correlation between the concentration of this drug and clinical presentation or cause of death was reported in this sample. However, the potential for harm associated with low concentrations of MDMB-CHMICA and the
symptoms of toxicity being non-specific was highlighted
A systematic characterization of cognitive techniques for learning from textual and pictorial representations
Pictorial representations can play a pivotal role in both printed and digital learning material. Although there has been extensive research on cognitive techniques and strategies for learning from text, the same cannot be said for static and dynamic pictorial representations. In this paper we propose a systematic characterization of cognitive learning techniques that is founded on both theoretical and empirical research. The characterization relates the learning techniques to classes of cognitive processes as well as to textual and pictorial representations. We show how successful strategies for learning from both plain text and illustrated text are covered by the characterization. We also exemplify how the construction of new strategies for pictorial representations can be informed by the characterization
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