Establishing a sustainable and cross-boundary geospatial cyberinfrastructure to enable polar research

Polar Regions become increasingly important as places for (1) natural resources, (2) sensitive indicators of human activities and global, environment, and climate changes, (3) preserving histories of the Earth and biological evolution, and (4) space-Earth interactions and answers to many other 21st century challenges. To facilitate the research, exploration, and development for better understanding, utilizing, and protecting the Polar Regions, a Geospatial CyberInfrastructure (GCI) is needed to help us collect data, integrate information gathered or data in real time from in situ and satellite sensors, and model the geophysical, biological, ecological, and social phenomena to provide better decision support information for policymakers. This special issue of GCI and polar research captures the recent advancements in polar research and the requirements for a GCI. Through a rigorous review process, four papers were selected based on their relationships to polar research and their scientific/technical merits. This paper is a review that surveys the field, introduces the selected papers, and discusses future research.     

An Eddy-Covariance System for the Measurement of Surface/Atmosphere Exchange Fluxes of Submicron Aerosol Chemical Species—First Application Above an Urban Area

Until now, micrometeorological measurements of surface/ atmosphere exchange fluxes of submicron aerosol chemical components such as nitrate, sulfate or organics could only be made with gradient techniques. This article describes a novel setup to measure speciated aerosol fluxes by the more direct eddy covariance technique. The system is based on the Aerodyne quadrupole-based Aerosol Mass Spectrometer (Q-AMS), providing a quantitative measurement of aerosol constituents of environmental concern at a time resolution sufficient for eddy-covariance. The Q-AMS control software was modified to maximize duty cycle and statistics and enable fast data acquisition, synchronized with that of an ultrasonic anemometer. The detection limit of the Q-AMS based system for flux measurements ranges from 0.2 for NO₃ ^? to 15 ng m^?2 s^?1 for hydrocarbon-like organic aerosol (HOA), with an estimated precision of around 6 ng m^?2 s^?1, depending on aerosol loading. At common ambient concentrations the system is capable of resolving deposition velocity values < 1 mm s^?1, sufficient for measurements of dry deposition to vegetation. First tests of the system in the urban environment (6 to 20 June 2003) in Boulder, CO, USA, reveal clear diurnal, presumably traffic related, patterns in the emission of HOA and NO₃ ^?, with indication of fast production of moderately oxygenated organic aerosol below the measurement height, averaging about 15% of the HOA emission. The average emission factor for HOA was 0.5 g (kg fuel)^?1, similar to those found in previous studies. For NO₃ ^? an emission factor of 0.09 g (kg fuel)^?1 was estimated, implying oxidation of 0.5% of the traffic derived NO_x below the measurement height of 45 m. By contrast, SO₄ ^2? fluxes were on average downward, with deposition velocities that increase with friction velocity from 0.4 to 4 mm s^?1.     

International Society of Sports Nutrition position stand: Nutrient timing

Background

The present experiment examined the responses of peripheral modulators and indices of brain serotonin (5-HT) and dopamine (DA) function and their association with perception of effort during prolonged exercise in the heat after creatine (Cr) supplementation.

Methods

Twenty one endurance-trained males performed, in a double-blind fashion, two constant-load exercise tests to exhaustion at 63 ± 5% O _{2 max} in the heat (ambient temperature: 30.3 ± 0.5 °C, relative humidity: 70 ± 2%) before and after 7 days of Cr (20 g·d^-1 Cr + 140 g·d^-1 glucose polymer) or placebo (Plc) (160 g·d^-1 glucose polymer) supplementation.

Results

3-way interaction has shown that Cr supplementation reduced rectal temperature, heart rate, ratings of perceived leg fatigue (P < 0.05), plasma free-tryptophan (Trp) (P < 0.01) and free-Trp:tyrosine ratio (P < 0.01) but did not influence the ratio of free-Trp:large neutral amino acids or contribute in improving endurance performance (Plc group, n = 10: 50.4 ± 8.4 min vs. 51.2 ± 8.0 min, P > 0.05; Cr group, n = 11: 47.0 ± 4.7 min vs. 49.7 ± 7.5 min, P > 0.05). However, after dividing the participants into "responders" and "non-responders" to Cr, based on their intramuscular Cr uptake, performance was higher in the "responders" relative to "non-responders" group (51.7 ± 7.4 min vs.47.3 ± 4.9 min, p < 0.05).

Conclusion

although Cr influenced key modulators of brain 5-HT and DA function and reduced various thermophysiological parameters which all may have contributed to the reduced effort perception during exercise in the heat, performance was improved only in the "responders" to Cr supplementation. The present results may also suggest the demanding of the pre-experimental identification of the participants into "responders" and "non-responders" to Cr supplementation before performing the main experimentation. Otherwise, the possibility of the type II error may be enhanced.     

International society of sports nutrition position stand: caffeine and performance

Background

We compared Glycine Propionyl-L-Carnitine (GlycoCarn^®) and three different pre-workout nutritional supplements on measures of skeletal muscle oxygen saturation (StO₂), blood nitrate/nitrite (NOx), lactate (HLa), malondialdehyde (MDA), and exercise performance in men.

Methods

Using a randomized, double-blind, cross-over design, 19 resistance trained men performed tests of muscular power (bench press throws) and endurance (10 sets of bench press to muscular failure). A placebo, GlycoCarn^®, or one of three dietary supplements (SUPP1, SUPP2, SUPP3) was consumed prior to exercise, with one week separating conditions. Blood was collected before receiving the condition and immediately after exercise. StO₂ was measured during the endurance test using Near Infrared Spectroscopy. Heart rate (HR) and rating of perceived exertion (RPE) were determined at the end of each set.

Results

A condition effect was noted for StO₂ at the start of exercise (p = 0.02), with GlycoCarn^® higher than SUPP2. A condition effect was also noted for StO₂ at the end of exercise (p = 0.003), with SUPP1 lower than all other conditions. No statistically significant interaction, condition, or time effects were noted for NOx or MDA (p > 0.05); however, MDA decreased 13.7% with GlycoCarn^® and increased in all other conditions. Only a time effect was noted for HLa (p < 0.0001), with values increasing from pre- to post-exercise. No effects were noted for HR, RPE, or for any exercise performance variables (p > 0.05); however, GlycoCarn^® resulted in a statistically insignificant greater total volume load compared to the placebo (3.3%), SUPP1 (4.2%), SUPP2 (2.5%), and SUPP3 (4.6%).

Conclusion

None of the products tested resulted in favorable changes in our chosen outcome measures, with the exception of GlycoCarn^® in terms of higher StO₂ at the start of exercise. GlycoCarn^® resulted in a 13.7% decrease in MDA from pre- to post-exercise and yielded a non-significant but greater total volume load compared to all other conditions. These data indicate that 1) a single ingredient (GlycoCarn^®) can provide similar practical benefit than finished products containing multiple ingredients, and 2) while we do not have data in relation to post-exercise recovery parameters, the tested products are ineffective in terms of increasing blood flow and improving acute upper body exercise performance.     

Carbohydrate Restriction has a More Favorable Impact on the Metabolic Syndrome than a Low Fat Diet

We recently proposed that the biological markers improved by carbohydrate restriction were precisely those that define the metabolic syndrome (MetS), and that the common thread was regulation of insulin as a control element. We specifically tested the idea with a 12-week study comparing two hypocaloric diets (~1,500 kcal): a carbohydrate-restricted diet (CRD) (%carbohydrate:fat:protein = 12:59:28) and a low-fat diet (LFD) (56:24:20) in 40 subjects with atherogenic dyslipidemia. Both interventions led to improvements in several metabolic markers, but subjects following the CRD had consistently reduced glucose (−12%) and insulin (−50%) concentrations, insulin sensitivity (−55%), weight loss (−10%), decreased adiposity (−14%), and more favorable triacylglycerol (TAG) (−51%), HDL-C (13%) and total cholesterol/HDL-C ratio (−14%) responses. In addition to these markers for MetS, the CRD subjects showed more favorable responses to alternative indicators of cardiovascular risk: postprandial lipemia (−47%), the Apo B/Apo A-1 ratio (−16%), and LDL particle distribution. Despite a threefold higher intake of dietary saturated fat during the CRD, saturated fatty acids in TAG and cholesteryl ester were significantly decreased, as was palmitoleic acid (16:1n-7), an endogenous marker of lipogenesis, compared to subjects consuming the LFD. Serum retinol binding protein 4 has been linked to insulin-resistant states, and only the CRD decreased this marker (−20%). The findings provide support for unifying the disparate markers of MetS and for the proposed intimate connection with dietary carbohydrate. The results support the use of dietary carbohydrate restriction as an effective approach to improve features of MetS and cardiovascular risk. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Class 1 and class 2 integrons in poultry carcasses from broiler house and poultry processing environments

Integrons have been identified as major genetic contributors to the dissemination of antimicrobial resistance in bacteria. The objective of this study was to examine the prevalence of integrons in poultry processing at the broiler house and in processing plants. Class 1 and class 2 integrons were found throughout the processing environment. Of the two classes of integrons, class 1 was the most prevalent in all processing areas. The levels of both classes of integrons decreased from the farm to the processing plant. Within the chiller tank in the processing plant, the persistence of these sequences appears to be related to the free chlorine concentration of the chiller tank water. The variable regions of the amplified integrons showed size diversity (from 680 to 2,000 bp), suggesting diversity in types of antibiotic-resistance-coding gene cassettes. The presence of the class 1 and class 2 integrons in the chlorinated chiller tank suggests that these sequences are capable of withstanding this critical step in the reduction of microbial loads on poultry carcasses. The persistence of the integron gene sequences on the farm and throughout processing highlights the stability of these transmissible antibiotic-resistance-coding nucleotide sequences and their potential role as reservoirs of antibiotic-resistance-coding genetic elements within the poultry rearing and processing environments.     

Energy-Efficient Transmission Range Optimization Model for WSN-Based Internet of Things

With the explosive advancements in wireless communications and digital electronics, some tiny devices, sensors, became a part of our daily life in numerous fields. Wireless sensor networks (WSNs) is composed of tiny sensor devices. WSNs have emerged as a key technology enabling the realization of the Internet of Things (IoT). In particular, the sensor-based revolution of WSN-based IoT has led to considerable technological growth in nearly all circles of our life such as smart cities, smart homes, smart healthcare, security applications, environmental monitoring, etc. However, the limitations of energy, communication range, and computational resources are bottlenecks to the widespread applications of this technology. In order to tackle these issues, in this paper, we propose an Energy-efficient Transmission Range Optimized Model for IoT (ETROMI), which can optimize the transmission range of the sensor nodes to curb the hot-spot problem occurring in multi-hop communication. In particular, we maximize the transmission range by employing linear programming to alleviate the sensor nodes’ energy consumption and considerably enhance the network longevity compared to that achievable using state-of-the-art algorithms. Through extensive simulation results, we demonstrate the superiority of the proposed model. ETROMI is expected to be extensively used for various smart city, smart home, and smart healthcare applications in which the transmission range of the sensor nodes is a key concern.     

Metals in the sediments of the Huron-Erie Corridor in North America: Factors regulating metal distribution and mobilization

Sediment samples from the Huron‐Erie Corridor (Great Lakes, North America) were collected to quantify the relative importance of natural and anthropogenic sources of contamination, and to study the spatial metal distribution patterns of metals as a function of the characteristics of the Corridor sediments. A stratified random sampling design was used to measure the spatial patterns of metal inputs, settling and sorting along the length of the Corridor. Factors regulating metal mobilization were assessed by determining metal affinities with the total organic fraction (TOM), the mineral fraction (represented as Al), and the granulometric characteristic (represented as <0.063 mm fraction). The study revealed that anthropogenic factors primarily regulated metal distributions and mobilization throughout the Huron‐Erie Corridor. In the St. Clair and Detroit Rivers, the spatial pattern of metal distributions strongly reflected local industrial sources. In the Walpole Delta and Lake St. Clair, however, inorganic (clays) and organic (TOM) particles dominated the contaminant distribution. Sediment contamination issues throughout the Huron‐Erie Corridor were dominated by mercury, released from sources along the St. Clair and Detroit Rivers. The mean enrichment factor EF_Al for mercury in these sediments has reached 68.3. Other metal pollutants were confined to the sediments in the lower depositional reach of the Corridor.