The Effect of Load Deception on Kinetic Variables during the Second Pull from Blocks of the Power Clean

Strength & conditioning practitioners often seek novel and applied methods to enhance athletic performance. The purpose of this current research was to examine whether ‘not knowing the load ‘during a mid-thigh pull (MTP) performance led to enhanced performance characteristics across a randomised selection of loads (75%-95% 1RM). Fifteen male collegiate athletes (age 21.8 ± 2.3, height 171.8 ± 7.5 cm, mass 89.3kg ± 9.8kg, MTP 1RM 135.5kg ± 18kg) were selected for the pre 1RM MTP and the 5 post randomised unknown lifts between 75%-95% of individual 1RM. The research demonstrated that unknown loads at 75% 1RM lead to significant changes in average power (AP) (known1062±251 W, unknown1213 ± 289W; p ≤ 0.05; effect size (ES) = 0.56 small). Unknown loads at 75% 1RM lead to significant changes in average velocity (AV) (known: 0.49±0.1, unknown: 0.66 ± 0.10m/s; p ≤ 0.00; ES = 1.66 large). There was also a significant change in peak velocity (PV) at 75% 1RM (known: 0.74±0.16, unknown: 0.95 ± 0.26m/s; p ≤ 0.05; ES = 0.99 moderate). Unknown loads at 80% 1RM lead to significant changes in AV (known: 0.47±0.10 unknown: 0.60 ± 0.10m/s; p ≤ 0.01; ES = 1.36 large). There was no significant difference in AP, AV, peak power (PP) and PV variables across 85, 90, 95% 1RM (p ≥ 0.05; ES = trivial to small). It appears that these findings especially at unknown loads between 75% and 80% 1RM could be beneficial in enhancing velocity-based performance variables. Therefore, the applications of unknown loads are of meaningful practical use to enhance performance variables during weightlifting pulling derivatives. Therefore, weightlifting pulling derivatives are potentially a useful training modality to improve desirable ballistic actions in particular triple extension

Reconstruction of an extreme flood hydrograph and morphodynamics of a meander bend in a high-peak discharge variability river (Powder River, USA)

AbstractUnderstanding of morphodynamic processes associated with large‐scale floods has recently improved following significant advances of modern technologies. Nevertheless, a clear link between flood discharge and in‐channel sedimentation processes remains to be resolved. The hydrological and geomorphological data available for the meandering Powder River (Montana, USA) since 1977 makes it a perfect laboratory to investigate connections between flood discharge and point‐bar sedimentation processes. This study focuses on a point‐bar that accreted laterally ca 70 m during a 50‐year recurrence flood, which lasted about 14 days in May 1978. In September 2018, a trench ca 2 m deep and 70 m long was excavated through the axial point‐bar deposits, and the 1978 flood deposits were delineated based on georeferenced pre‐flood and post‐flood cross‐section surveys. Sedimentological data show that point‐bar deposits accumulated at the early and late flood stages, when the flow was confined to the channel, and have similarities with classical facies models in terms of palaeocurrent patterns and vertical grain‐size trend. However, during high‐stage flood conditions, when the flow overtopped the bar, cross‐cutting of the bar and armouring were typical processes. Integration of sedimentological and palaeo‐hydrological data highlight that the relation between channel cross‐sectional area and flood discharge play a key role in preserving bar deposits. The integrated approach adopted here provides a basis for advancing palaeoflood hydrology beyond the stage of estimating peak discharges to the next stage of estimating palaeoflood hydrographs

Escape tactics used by bluegills and fathead minnows to avoid predation by tiger muskellunge

To explain why esocids prefer cylindrical, soft-rayed prey over compressed, spiny-rayed prey, we quantified behavioral interaction between tiger muskellunge (F1 hybrid of male northern pike Esox lucius and female muskellunge E. masquinongy) and fathead minnows (Pimephales promelas) and bluegills (Lepomis macrochirus). Tiger muskellunge required four times as many strikes and longer pursuits to capture bluegills than fathead minnows. Tiger muskellunge attacked each prey species differently; fathead minnows were grasped at midbody and bluegills were attacked in the caudal area. Each prey species exhibited different escape tactics. Fathead minnows remained in open water and consistently schooled; bluegills dispersed throughout the tank and sought cover by moving to corners and edges. Due to their antipredatory behavior (dispersing, cover seeking, and remaining motionless) and morphology (deep body and spines), bluegills were less susceptible to capture by tiger muskellunge than were fathead minnows.Funding for this project was provided by the Federal Aid in Fish Restoration Act under Dingell-Johnson Project F-57-R

Physiological niche and geographical range in European diving beetles (Coleoptera: Dytiscidae).

Geographical ranges vary greatly in size and position, even within recent clades, but the factors driving this remain poorly understood. In aquatic beetles, thermal niche has been shown to be related to both the relative range size and position of congeners but whether other physiological parameters play a role is unknown. Metabolic plasticity may be critical for species occupying more variable thermal environments and maintaining this plasticity may trade-off against other physiological processes such as immunocompetence. Here we combine data on thermal physiology with measures of metabolic plasticity and immunocompetence to explore these relationships in Deronectes (Dytiscidae). While variation in latitudinal range extent and position was explained in part by thermal physiology, aspects of metabolic plasticity and immunocompetence also appeared important. Northerly distributed, wide-ranging species apparently used different energy reserves under thermal stress from southern endemic congeners and differed in their antibacterial defences. This is the first indication that these processes may be related to geographical range, and suggests parameters that may be worthy of exploration in other taxa

Vector vortex coronagraph: first results in the visible

We report the status of JPL and JDSU ongoing technological developments and contrast results of the vector vortex coronagraph (VVC) made out of liquid crystal polymers (LCP). The first topological charge 4 VVC was tested on the high contrast imaging testbed (HCIT) around 800 nm, under vacuum and with active wavefront control (32x32 Xinetics deformable mirror). We measured the inner working angle or IWA (50% off-axis transmission) at ~ 1.8λ/d. A one-sided dark hole ranging from 3λ/d to 10λ/d was created in polarized light, showing a mean contrast of ~ 2 × 10^(-7) over a 10% bandwidth. This contrast was maintained very close in (3 λ/d) in a reduced 2% bandwidth. These tests begin to demonstrate the potential of the LCP technology in the most demanding application of a space-based telescope dedicated to extrasolar planet characterization. The main limitations were identified as coming from incoherent sources such as multiple reflections, and residual chromaticity. A second generation of improved masks tackling these issues is being manufactured and will be tested on the HCIT in the coming months

A Multi-wavelength Differential Imaging Experiment for the High Contrast Imaging Testbed

We discuss the results of a multi-wavelength differential imaging lab experiment with the High Contrast Imaging Testbed (HCIT) at the Jet Propulsion Laboratory. The HCIT combines a Lyot coronagraph with a Xinetics deformable mirror in a vacuum environment to simulate a space telescope in order to test technologies and algorithms for a future exoplanet coronagraph mission. At present, ground based telescopes have achieved significant attenuation of speckle noise using the technique of spectral differential imaging (SDI). We test whether ground-based SDI can be generalized to a non-simultaneous spectral differential imaging technique (NSDI) for a space mission. In our lab experiment, a series of 5 filter images centered around the O2(A) absorption feature at 0.762 um were acquired at nominal contrast values of 10^-6, 10^-7, 10^-8, and 10^-9. Outside the dark hole, single differences of images improve contrast by a factor of ~6. Inside the dark hole, we found significant speckle chromatism as a function of wavelength offset from the nulling wavelength, leading to a contrast degradation by a factor of 7.2 across the entire ~80 nm bandwidth. This effect likely stems from the chromatic behavior of the current occulter. New, less chromatic occulters are currently in development; we expect that these new occulters will resolve the speckle chromatism issue.Comment: 24 pages, 8 figures, 3 tables, accepted by PAS

Femtosecond-laser-induced delamination and blister formation in thermal oxide films on silicon (100)

Silicon (100) substrates with thermal oxide films of varying thickness were irradiated with single and multiple 150 fs150fs laser pulses at normal and non-normal incidences. A range of laser fluence was found in which a blister or domelike feature was produced where the oxide film was delaminated from the substrate. At normal and non-normal incidences blister features were observed for samples with 54, 147, and 1200 nm1200nm of thermal oxide. The blister features were analyzed with optical and atomic force microscopy. In addition, the time frame for blister growth was obtained using pump-probe imaging techniques.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87772/2/153121_1.pd

Gettysburg College Sustainability Proposal

In the fall of 2011, the Environmental Studies capstone class led by Professor Rutherford Platt was asked to write Gettysburg College’s first Sustainability Plan. The goal of the plan was to develop specific sustainable practices for the campus that were related to the three pillars of sustainability: economic, social, and environmental, and how integrating diligent sustainable practices into each of these respected pillars will result in a more conscious campus, community, and future. In 2010, Gettysburg College turned to the Sustainability Tracking Assessment and Rating System (STARS) to quantify the institution’s sustainability efforts, providing a self-check mechanism to encourage sustainability applications to all aspects of the College. The American College and University Presidents’ Climate Commitment was signed in 2007 by former Gettysburg College President Katherine Haley Will, declaring that Gettysburg College would become carbon neutral by 2032. Gettysburg College has made large strides in the search for sustainability, and aims to continue its dedication to furthering sustainable practice. The following plan outlines the six priority areas identified by the Capstone class: progress of the American College and University Presidents’ Climate Commitment, Dining Services, campus green space, community outreach, integration of sustainability into the Gettysburg College Curriculum, and the Sustainability Advisory Committee. The first priority area identified was monitoring and upholding the American College and University Presidents’ Climate Commitment (ACUPCC). Though creating new sustainability initiatives on campus is the driving force towards an increasingly sustainable college and community, it is imperative that these goals be carried out in full to maximize beneficial returns. In order to reach carbon neutrality, Gettysburg College hopes to increase energy efficiency in buildings, incorporate renewable energy sources on campus, and mitigate remaining emissions through the purchase of carbon offsets. To further the College’s progress, it is proposed that Gettysburg College continue its energy-efficient appliance purchasing policy, as well as create a policy to offset all greenhouse gas emissions generated by air travel for students study abroad. As stated by the ACUPCC, a Sustainability Committee should take responsibility for the updates and progress reports required to meet the goal of carbon neutrality. The second priority area identified was sustainability in Dining Services. Gettysburg College is home to 2,600 students, all of whom require three full meals a day. Dining Services accounts for a large fraction of Gettysburg College’s sustainability efforts, already implementing sustainability through composting, buying local produce, and using biodegradable products. The proposed on-campus sales cuts of non-reusable to-go items, a change in campus mentality on food waste, and improved composting practices will translate to an increasingly sustainable campus, as well as a well-fed campus body. The third priority was maintaining green space on campus. Ranked as the 23rd most beautiful campus in the United States by The Best Colleges, Gettysburg College utilizes campus green space to create an atmosphere that is conducive to activity as well as tranquility. The plan proposes that Gettysburg College and its grounds facilities continue their exceptional efforts, focusing on increasing the use of the student garden, creating a new rain garden or social area on campus, and converting unnecessary parking lots into green space. As these additions are completed, they must be introduced to the student body and faculty alike to assure these areas are known and utilized. The fourth priority was utilizing community outreach to spread awareness of sustainability initiatives on and off campus. To connect the sustainability-geared changes proposed in this plan, community outreach at Gettysburg College is assessed to estimate how well these initiatives are communicated and promoted to both potential and enrolled students, faculty, and other concerned parties. To evaluate the efficiency of communication at Gettysburg College, a quantitative assessment is presented to measure the ease of finding the sustainability webpage, the quality of sustainability-related topics available on the webpage, and quality of webpage design. The webpage is in need of improved text to image ratios, locations of sustainability topics, and data displays. Despite not having a link to the sustainability webpage on the Gettysburg College homepage, sustainability events should be covered and presented on the rotational news feed found on the homepage to maximize outreach to interested parties or simply to add to the definition of Gettysburg College. The fifth priority was integrating sustainability into the Curriculum to build a culture on campus that values academic rigor, supports students as they cultivate intellectual and civic passions, and promotes the development of healthy social relationships and behaviors. The proposed Sustainability Committee on Sustainability in the Curriculum (SCC) will hold sustainability workshops for faculty with the aim to instill sustainability into all academic disciplines, providing all Gettysburg graduates with a means to approach their professional careers in a fashion that is conscious of sustainability. The sixth and last priority was the Sustainability Advisory Committee. Established in 2007, the Sustainability Advisory Committee is currently under review, but it is recommended that the committee restructure itself in accordance with the new Sustainability Committee Bylaws. These bylaws aim to define the purposes, membership, governance, and involvement with the college. With a clearly defined set of goals and methodology, the Sustainability Advisory Committee will be able to improve the solidarity of the sustainability movement on campus as a whole. By following the propositions laid out in the Gettysburg College Sustainability Plan, the student body, faculty, and community alike will become a part of a multi-faceted progression toward a more sustainable future

On the origin and evolution of microbial mercury methylation

The origin of microbial mercury methylation has long been a mystery. Here, we employed genome-resolved phylogenetic analyses to decipher the evolution of the mercury-methylating gene, hgcAB, constrain the ancestral origin of the hgc operon, and explain the distribution of hgc in Bacteria and Archaea. We infer the extent to which vertical inheritance and horizontal gene transfer have influenced the evolution of mercury methylators and hypothesize that evolution of this trait bestowed the ability to produce an antimicrobial compound (MeHg+) on a potentially resource-limited early Earth. We speculate that, in response, the evolution of MeHg+-detoxifying alkylmercury lyase (encoded by merB) reduced a selective advantage for mercury methylators and resulted in widespread loss of hgc in Bacteria and Archaea

Atom probe tomography of a Cu-doped TiNiSn thermoelectric material : nanoscale structure and optimization of analysis conditions

Funding: The Oxford Atom Probe facility is funded by EPSRC (EP/M022803/1) and the Glasgow plasma focused ion beam system was funded by EPSRC grant EP/P001483/1. Thermoelectric materials were developed under joint EPSRC grants EP/N017218/1 and EP/N01717X/1.Cu-doping and crystallographic site occupations within the half-Heusler (HH) TiNiSn, a promising thermoelectric material, have been examined by atom probe tomography. In particular, this investigation aims to better understand the influence of atom probe analysis conditions on the measured chemical composition. Under a voltage-pulsing mode, atomic planes are clearly resolved and suggest an arrangement of elements in-line with the expected HH (F-43m space group) crystal structure. The Cu dopant is also distributed uniformly throughout the bulk material. For operation under laser-pulsed modes, the returned composition is highly dependent on the selected laser energy, with high energies resulting in the measurement of excessively high absolute Ti counts at the expense of Sn and in particular Ni. High laser energies also appear to be correlated with the detection of a high fraction of partial hits, indicating nonideal evaporation behavior. The possible mechanisms for these trends are discussed, along with suggestions for optimal analysis conditions for these and similar thermoelectric materials.PostprintPeer reviewe