235 research outputs found
Slip-Form Paving
The proper placement, consolidation, and finishing of low-slump concrete without the aid of pre-erected side, forms has been widely acclaimed as an economical and effective procedure in the construction of portland cement concrete pavements. This construction procedure, commonly referred to as slip-form paving, depends upon the ability of low-slump concrete to remain in place after consolidation and removal of forms.
Slip-form pavers differ from conventional pavers in that no fixed side forms are required inasmuch as the slip-form paver has side forms that advance with the machine. Concrete is merely deposited on the prepared subgrade in front of the machine, which strikes off and consolidates the concrete. The slab is then shaped by an extrusion plate and given an initial floating. The slab is given another floating and then dragged with a burlap drag. All that remains to be done is curing the concrete and sawing the joints. A slip-form paver replaces several pieces of equipment that are normally required for conventional paving. Not only is a reduction in capital investment brought about by the use of slip-form pavers, but a savings is also realized in the accompanying reduction of labor. Savings from 20 to 45 cents per square yard have been reported by other states
Detection and discrimination between ochratoxin producer and non-producer strains of Penicillium nordicum on a ham-based medium using an electronic nose
The aim of this work was to evaluate the potential use of qualitative volatile
patterns produced by Penicillium nordicum to discriminate between ochratoxin A
(OTA) producers and non-producer strains on a ham-based medium. Experiments were
carried out on a 3% ham medium at two water activities (aw ; 0.995, 0.95)
inoculated with P. nordicum spores and incubated at 25°C for up to 14days.
Growing colonies were sampled after 1, 2, 3, 7 and 14days, placed in 30-ml
vials, sealed and the head space analysed using a hybrid sensor electronic nose
device. The effect of environmental conditions on growth and OTA production was
evaluated based on the qualitative response. However, after 7days, it was
possible to discriminate between strains grown at 0.995 aw, and after 14days,
the OTA producer and non-producer strain and the controls could be discriminated
at both aw levels. This study suggests that volatile patterns produced by P.
nordicum strains may differ and be used to predict the presence of toxigenic
contaminants in ham. This approach could be utilised in ham production as part
of a quality assurance system for preventing OTA contaminatio
Effect of temperature and water activity on growth and ochratoxin A production boundaries of two Aspergillus carbonarius isolates on a simulated grape juice medium
Aims: To develop and validate a logistic regression model to predict the growth
and ochratoxin A (OTA) production boundaries of two Aspergillus carbonarius
isolates on a synthetic grape juice medium as a function of temperature and
water activity (aw)
Effect of Nitrogen and Phosphorus Application on Productivity, Nutrient Uptake and Quality of Teosinte (\u3cem\u3eZea mexicana\u3c/em\u3e L.) Fodder
Teosinte (Zea mexicana L.) is popularly known as Makchari being a close relative of maize. It provides succulent, palatable and nutritive fodder during Kharif season for feeding the animals as green fodder or conserved fodder in the form of silage. Teosinte is an excellent multicut fodder which gives high yield of nutritious green lush fodder in 65-70 days with less inputs as compared to maize. Nitrogen is an essential component of proteins, nucleic acid, enzymes, coenzymes, chlorophyll and cell wall. Phosphorus plays a vital role in crop production as it is involved in CO2 fixation, sugar metabolism, energy storage and transfer. Nutrient deficiency along with imbalanced and non-judicious fertilizers use of the important limiting factor that may affect the yield and quality of teosinte forage. In India about 62% and 49% soils are deficient in nitrogen and phosphorus (Gibson, 2006). The application of nitrogen and phosphorus is considered to be the most important which improves the yield and quality of fodder. The present investigation was under taken to assess the effect of N and P application on productivity, nutrient uptake and quality of teosinte fodder
T35: a small automatic telescope for long-term observing campaigns
The T35 is a small telescope (14") equipped with a large format CCD camera
installed in the Sierra Nevada Observatory (SNO) in Southern Spain. This
telescope will be a useful tool for the detecting and studying pulsating stars,
particularly, in open clusters. In this paper, we describe the automation
process of the T35 and show also some images taken with the new
instrumentation.Comment: 13 pages, 9 figures. Accepted for publication in the special issue
"Robotic Astronomy" of Advances of Astronom
Gender & Sport Related Differences in Electrocardiogram & Pre-Participation Exams (PPE) in College Age Athletes
Background and Purpose: The NCAA requires all college level athletes receive a pre-participation physical exam. However, the pre-participation exams occasionally do not require electrocardiogram screening to help detect cardiac abnormalities. Though electrocardiograms may not be available at all testing’s, using specific markers and finding differences between gender and sport abnormalities could help detect cardiac abnormalities. The purpose of this study was to determine if there were significant differences in resting 12-Lead ECG markers in a group NCAA Div. II collegiate level athletes.
Methods: Four hundred fifty-one college level athlete’s ages 18 to 25 participated in this study. Age, gender, height, weight, BMI, blood pressure and heart rate were measured during a pre-participation exam. Electrocardiogram measurements were gathered by using Mortara X-Scribe™ , Vacumed Turbo Fit 5™, Welch Allyn CardioPerfect™. Twelve-Lead ECGs were categorized by sport and analyzed by the lab director and the attending physician. One-way ANOVA was used to analyze differences in ECG findings in sports. Independent t-test and linear regression were used to analyze differences between male and female outcomes. Significance was set at the 0.05 level.
Results: No significant differences in wave durations were found between male and female athletes. However, P wave amplitude was higher in males (1.50 ± 0.61 mm) than females (1.44 ± .55 mm) (P=0.01). Males had higher resting blood pressures (SBP=123.1 ± 10.9 mmHg) (DBP=73.6 ± 8.1 mmHg) than females (SBP=112.6 ± 9.6 mmHg) (DBP=69.9 ± 7.9 mmHg) (P\u3c0.001). Males also had a higher frequency of arrhythmias, T wave inversions, and 1st degree atrioventricular blocks when compared to females. Similarly, SBP was significantly higher in football compared to all other sports. Relative to ECG parameters cross country athletes showed ECG changes typical for cardiovascular endurance training compared to all other sports including sinus bradycardia, increased RR interval, and leftward axis shift.
Discussion: Although marked differences in 12-lead ECG parameters were not found between sports in this sample, two athletes were sent for further echocardiogram evaluation due to abnormal ECGs, but were subsequently cleared to participate in their sport
Citizen Science and Open Data: a model for Invasive Alien Species in Europe
Invasive Alien Species (IAS) are a growing threat to Europe's biodiversity. The implementation of European Union Regulation on IAS can benefit from the involvement of the public in IAS recording and management through Citizen Science (CS) initiatives. Aiming to tackle issues related with the use of CS projects on IAS topics, a dedicated workshop titled “Citizen Science and Open Data: a model for Invasive Alien Species in Europe” was organized by the Joint Research Centre (JRC) and the European Cooperation in Science and Technology (COST Association). Fifty key stakeholders from all Europe, including two Members of the European Parliament, attended the workshop. With a clear focus on IAS, the workshop aimed at addressing the following issues: a) CS and policy, b) citizen engagement, and c) CS data management. Nine short presentations provided input on CS and IAS issues. Participants discussed specific topics in several round tables (“world café” style) and reported back their conclusions to the audience and full assembly moderated discussions. Overall, the workshop enabled the sharing of ideas, approaches and best practices regarding CS and IAS. Specific opportunities and pitfalls of using CS data in the whole policy cycle for IAS were recognized. Concerning the implementation of the IAS Regulation, CS data could complement official surveillance systems, and contribute to the early warning of the IAS of Union concern after appropriate validation by the Member States’ competent authorities. CS projects can additionally increase awareness and empower citizens. Attendees pointed out the importance for further public engagement in CS projects on IAS that demonstrate specific initiatives and approaches and analyze lessons learned from past experiences. In addition, the workshop noted that the data gathered from different CS projects on IAS are fragmented. It highlighted the need for using an open and accessible platform to upload data originating from CS sources or to mirror validated data into a single, easy-to-use web service, in line with the EU Open Science Strategic Priority. The workshop provided ten key recommendations of best practices for CS projects on IAS, addressed to researchers, policy makers and implementing authorities, indicating future research and policy directions and opportunities
Incidence and diversity of the fungal genera Aspergillus and Penicillium in Portuguese almonds and chestnuts
Almonds (Prunus dulcis (Miller) D.A. Webb) and European (sweet) chestnuts (Castanea sativa Miller) are of great economic and social impact in Mediterranean countries, and in some areas they constitute the main income of rural populations. Despite all efforts to control fungal contamination, toxigenic fungi are ubiquitous in nature and occur regularly in worldwide food supplies, and these nuts are no exception. This work aimed to provide knowledge on the general mycobiota of Portuguese almonds and chestnuts, and its evolution from field to the end of storage. For this matter, 45 field chestnut samples and 36 almond samples (30 field samples and six storage samples) were collected in Trás-os-Montes, Portugal. All fungi belonging to genus Aspergillus were isolated and identified to the section level. Fungi representative of other genera were identified to the genus level. In the field, chestnuts were mainly contaminated with the genera Fusarium, Cladosporium, Alternaria and Penicillium, and the genus Aspergillus was only rarely found, whereas almonds were more contaminated with Aspergillus. In almonds, Aspergillus incidence increased significantly from field to the end of storage, but diversity decreased, with potentially toxigenic isolates belonging to sections Flavi and Nigri becoming more significant and widespread throughout storage. These fungi were determined to be moderately associated, which can be indicative of mycotoxin co-contamination problems if adequate storage conditions are not secured.P. Rodrigues was supported by grants SFRH/BD/28332/2006 from Fundacao para a Ciencia e a Tecnologia (FCT), and SFRH/PROTEC/49555/2009 from FCT and Polytechnic Institute of Braganca, Portugal
Inhibitory effects of climate change on the growth and extracellular enzyme activities of a widespread Antarctic soil fungus
Temperatures approaching or exceeding 20 °C have been measured during summer in polar regions at the surfaces of barren fellfield soils under cloudless skies around solar noon. However, despite the upper temperature limit for the growth of cold‐adapted microbes – which are abundant in polar soils and have pivotal roles in nutrient cycling – typically being close to this temperature, previous studies have not addressed the consequences of climate change for the metabolism of these organisms in the natural environment. Here, in a five‐year field experiment on Alexander Island in the southern maritime Antarctic, we show that the abundance of Pseudogymnoascus roseus, the most widespread decomposer fungus in maritime Antarctic fellfield soils, is reduced by 1–2 orders of magnitude when irrigated and nutrient‐amended soils are warmed to >20 °C during summer. Laboratory experiments under conditions mimicking those during midsummer in the natural environment indicated that the hyphal extension rates of P. roseus isolates and the activities of five extracellular enzymes are reduced by 54–96% at high water availability after exposure to temperatures cycling daily from 2–21 °C and 2–24 °C, relative to temperatures cycling from 2–18 °C. Given that the temperatures of surface soils at the study site already reach 19 °C during midsummer, the observations reported here suggest that, at predicted rates of warming arising from moderate greenhouse gas emissions, inhibitory effects of climate change on the metabolism of P. roseus could manifest themselves within the next few decades. Furthermore, with peak temperatures at the surfaces of fellfield soils at other maritime Antarctic locations and in High Arctic and alpine regions already exceeding 20 °C during summer, the observations suggest that climate warming has the potential to inhibit the growth of other cold‐adapted microbes, with negative effects on soils as the Earth’s climate continues to war
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