Elementary Student Knowledge Gains In The Digital Portable Planetarium

Immersive environments provide unique and heightened sensory experiences that focus a learner’s attention, and thus may be useful learning platforms.  In particular, portable planetariums may be useful in advancing conceptual knowledge about the night sky, because they afford learners with Earth-based views of celestial motions, and give learners a sense of “being there.”  We demonstrate here that students make gains in knowledge about both apparent celestial motion and general astronomy concepts after viewing a 25-minute planetarium presentation.  However, the planetarium presentation did not appear to increase interest in astronomy and space science.  Our results suggest that the portable planetarium may be a useful strategy in supporting learners as they struggle with reconciling observed patterns with underlying, non-observable motions of the Earth, and with visualizing concepts such as the speed of planetary orbits relative to their position with respect to the sun

Muscle Contraction Duration and Fibre Recruitment Influence Blood Flow and VO2 Independent of Contractile Work during Steady-State Exercise in Humans

We tested the hypothesis that, among conditions of matched contractile work, shorter contraction durations and greater muscle fibre recruitment result in augmented skeletal muscle blood flow and oxygen consumption (O2) during steady-state exercise in humans. To do so, we measured forearm blood flow (FBF; Doppler ultrasound) during 4 minutes of rhythmic handgrip exercise in 24 healthy young adults and calculated forearm O2 via blood samples obtained from a catheter placed in retrograde fashion into a deep vein draining the forearm muscle. In Protocol 1 (n = 11), subjects performed rhythmic isometric handgrip exercise at mild and moderate intensities under conditions in which tension time index (TTI; isometric analog of work) was held constant but contraction duration was manipulated. In this protocol, shorter contraction durations led to greater FBF (184 ± 25 vs. 164 ± 25 ml·min-1) and O2 (23 ± 3 vs. 17 ± 2 ml·min-1; both PPper se during steady-state exercise in humans

Reactive Hyperemia Occurs Via Activation of Inwardly Rectifying Potassium Channels and Na+/K+-ATPase in Humans

Rationale: Reactive hyperemia (RH) in the forearm circulation is an important marker of cardiovascular health, yet the underlying vasodilator signaling pathways are controversial and thus remain unclear. Objective: We hypothesized that RH occurs via activation of inwardly rectifying potassium (KIR) channels and Na+/K+-ATPase and is largely independent of the combined production of the endothelial autocoids nitric oxide (NO) and prostaglandins in young healthy humans. Methods and Results: In 24 (23±1 years) subjects, we performed RH trials by measuring forearm blood flow (FBF; venous occlusion plethysmography) after 5 minutes of arterial occlusion. In protocol 1, we studied 2 groups of 8 subjects and assessed RH in the following conditions. For group 1, we studied control (saline), KIR channel inhibition (BaCl2), combined inhibition of KIR channels and Na+/K+-ATPase (BaCl2 and ouabain, respectively), and combined inhibition of KIR channels, Na+/K+-ATPase, NO, and prostaglandins (BaCl2, ouabain, L-NMMA [NG-monomethyl-L-arginine] and ketorolac, respectively). Group 2 received ouabain rather than BaCl2 in the second trial. In protocol 2 (n=8), the following 3 RH trials were performed: control; L-NMMA plus ketorolac; and L-NMMA plus ketorolac plus BaCl2 plus ouabain. All infusions were intra-arterial (brachial). Compared with control, BaCl2 significantly reduced peak FBF (−50±6%; P2 (−61±3%) and ouabain (−44±12%) alone, and this effect was enhanced when combined (−87±4%), nearly abolishing RH. L-NMMA plus ketorolac did not impact total RH FBF before or after administration of BaCl2 plus ouabain. Conclusions: Activation of KIR channels is the primary determinant of peak RH, whereas activation of both KIR channels and Na+/K+-ATPase explains nearly all of the total (AUC) RH in humans

Impaired Peripheral Vasodilation during Graded Systemic Hypoxia in Healthy Older Adults: Role of the Sympathoadrenal System

Systemic hypoxia is a physiological and pathophysiological stress that activates the sympathoadrenal system and, in young adults, leads to peripheral vasodilation. We tested the hypothesis that peripheral vasodilation to graded systemic hypoxia is impaired in older healthy adults and that this age-associated impairment is due to attenuated β-adrenergic mediated vasodilation and elevated α-adrenergic vasoconstriction. Forearm blood flow was measured (Doppler ultrasound) and vascular conductance (FVC) was calculated in 12 young (24±1 yrs) and 10 older (63±2 yrs) adults to determine the local dilatory responses to graded hypoxia (90, 85, and 80% O2 saturations) in control conditions, following local intra-arterial blockade of β-receptors (propranolol), and combined blockade of α+β receptors (phentolamine + propranolol). Under control conditions, older adults exhibited impaired vasodilation to hypoxia compared with young at all levels of hypoxia (peak ΔFVC at 80% SpO2 = 4±6 vs. 35±8%; P\u3c0.01). During β-blockade, older adults actively constricted at 85 and 80% SpO2 (peak ΔFVC at 80% SpO2= -13±6%; P\u3c0.05 vs. control) whereas the response in the young was not significantly impacted (peak ΔFVC = 28±8%). Combined α+β blockade increased the dilatory response to hypoxia in young adults, however older adults failed to significantly vasodilate (peak ΔFVC at 80% SpO2= 12±11% vs. 58±11%; P\u3c0.05). Our findings indicate that peripheral vasodilation to graded systemic hypoxia is significantly impaired in older adults which cannot be fully explained by altered sympathoadrenal control of vascular tone. Thus, the impairment in hypoxic vasodilation is likely due to attenuated local vasodilatory and/or augmented vasoconstrictor signaling with age

Magnetic Field Amplification by Small-Scale Dynamo Action: Dependence on Turbulence Models and Reynolds and Prandtl Numbers

The small-scale dynamo is a process by which turbulent kinetic energy is converted into magnetic energy, and thus is expected to depend crucially on the nature of turbulence. In this work, we present a model for the small-scale dynamo that takes into account the slope of the turbulent velocity spectrum v(l) ~ l^theta, where l and v(l) are the size of a turbulent fluctuation and the typical velocity on that scale. The time evolution of the fluctuation component of the magnetic field, i.e., the small-scale field, is described by the Kazantsev equation. We solve this linear differential equation for its eigenvalues with the quantum-mechanical WKB-approximation. The validity of this method is estimated as a function of the magnetic Prandtl number Pm. We calculate the minimal magnetic Reynolds number for dynamo action, Rm_crit, using our model of the turbulent velocity correlation function. For Kolmogorov turbulence (theta=1/3), we find that the critical magnetic Reynolds number is approximately 110 and for Burgers turbulence (theta=1/2) approximately 2700. Furthermore, we derive that the growth rate of the small-scale magnetic field for a general type of turbulence is Gamma ~ Re^((1-theta)/(1+theta)) in the limit of infinite magnetic Prandtl numbers. For decreasing magnetic Prandtl number (down to Pm approximately larger than 10), the growth rate of the small-scale dynamo decreases. The details of this drop depend on the WKB-approximation, which becomes invalid for a magnetic Prandtl number of about unity.Comment: 13 pages, 8 figures; published in Phys. Rev. E 201

Effects of Relaxation and Deep-Breathing on High School Students: ACT Prep

The purpose of this study was to relieve test anxiety in high school juniors preparing to take the ACT: a high-stakes, college admissions, standardized test. Participants included 81 eleventh grade students (25 males, 56 females) from a Midwestern public high school. Results demonstrated that relaxation training in the experimental group significantly lowered student’s perceptions of test anxiety from pre-test to post-test. Further research regarding systematic deep breathing and relaxation techniques is needed

Effects of Relaxation and Deep-Breathing on High School Students: ACT Prep

The purpose of this study was to relieve test anxiety in high school juniors preparing to take the ACT: a high-stakes, college admissions, standardized test. Participants included 81 eleventh grade students (25 males, 56 females) from a Midwestern public high school. Results demonstrated that relaxation training in the experimental group significantly lowered student’s perceptions of test anxiety from pre-test to post-test. Further research regarding systematic deep breathing and relaxation techniques is needed

Crystal cookery – using high-throughput technologies and the grocery store as a teaching tool

Using high-throughput crystallization screening technologies and data analysis, an educational program has been developed to teach the scientific method through crystallization and access to a grocery store, a post office and the internet

Prospectus, March 2, 1994

https://spark.parkland.edu/prospectus_1994/1003/thumbnail.jp

A novel MC1R allele for black coat colour reveals the Polynesian ancestry and hybridization patterns of Hawaiian feral pigs

Pigs (Sus scrofa) have played an important cultural role in Hawaii since Polynesians first introduced them in approximately AD 1200. Additional varieties of pigs were introduced following Captain Cook’s arrival in Hawaii in 1778 and it has been suggested that the current pig population may descend primarily, or even exclusively, from European pigs. Although populations of feral pigs today are an important source of recreational hunting on all of the major islands, they also negatively impact native plants and animals. As a result, understanding the origins of these feral pig populations has significant ramifications for discussions concerning conservation management, identity and cultural continuity on the islands. Here, we analysed a neutral mitochondrial marker and a functional nuclear coat colour marker in 57 feral Hawaiian pigs. Through the identification of a new mutation in the MC1R gene that results in black coloration, we demonstrate that Hawaiian feral pigs are mostly the descendants of those originally introduced during Polynesian settlement, though there is evidence for some admixture. As such, extant Hawaiian pigs represent a unique historical lineage that is not exclusively descended from feral pigs of European originPeer reviewe