Higher SL Research Articles

Geometric entropy of plant leaves: A measure of morphological complexity.

Shape is an objective characteristic of an object. A boundary separates a physical object from its surroundings. It defines the shape and regulates energy flux into and from an object. Visual perception of a definite shape (geometry) of physical objects is an abstraction. While the perceived geometry at an object's sharp interface (macro) creates a Euclidian illusion of actual shape, the notion of diffuse interfaces (micro) allows an understanding of the realistic form of objects. Here, we formulate a dimensionless geometric entropy of plant leaves (SL) by a 2-D description of a phase-field function. We applied this method to 112 tropical plant leaf images. SL was estimated from the leaf perimeter (P) and leaf area (A). It correlates positively with a fractal dimensional measure of leaf complexity, viz., segmental fractal complexity. Leaves with a higher P: A ratio have higher SL and possess complex morphology. The univariate cluster analysis of SL reveals the taxonomic relationship among the leaf shapes at the genus level. An increase in SL of plant leaves could be an evolutionary strategy. The results of morphological complexity presented in this paper will trigger discussion on the causal links between leaf adaptive stability/efficiency and complexity. We present SL as a derived plant trait to describe plant leaf complexity and adaptive stability. Integrating SL into other leaf physiological measures will help to understand the dynamics of energy flow between plants and their environment.

Active tectonics of the Thoubal‐Chandel Thrust, Manipur Hills, Indo‐Myanmar Range, northeast India: Insights into deformation pattern of adjacent thrust sheets in a growing orogen

The NE–SW trending and SE dipping Thoubal‐Chandel Thrust (TCT) in eastern Manipur Hills of the Indo‐Myanmar Range (IMR) places the Thoubal‐Chandel thrust sheet over the Churachandpur‐Mao thrust sheet. Despite being seismically active, the active tectonic aspects of the major structural discontinuities within the IMR, including TCT, are not yet studied in detail. The present study aims to examine the active tectonics of the TCT and other associated faults, with particular focus on deformation of the Churachandpur‐Mao, and Thoubal‐Chandel thrust sheets. Association and disposition of landforms, and statistical analyses of Mountain‐front Sinuosity Index (Smf), Stream Length‐Gradient Index (SL), Hypsometric Integral (HI), Drainage Basin Asymmetry Factor, and Transverse Topography Symmetry Factor (T) reveal that both of these adjacently lying thrust sheets are actively uplifting due to oblique‐slip movement on their basal thrusts, but with spatially variable rates. In general, higher SL (mode = 219) and HI (mode = 0.527) in large parts suggest faster uplift of the Thoubal‐Chandel thrust sheet than the Churachandpur‐Moa thrust sheet, which has comparatively lower SL (Mode = 140) and HI (mode = 0.416). However, differential along‐strike uplift rates have caused tilting of both the thrust sheets. Faster uplift of the northern part of Thoubal‐Chandel thrust sheet has caused its overall southward down‐tilting, whereas faster uplift of the southern part of Churachandpur‐Mao thrust sheet has caused its overall northward down‐tilting. The study brings out that the deformation pattern of even the adjacent thrust sheets of growing orogens could be at stark variance albeit the same stress regime.

The Effect of Warm-up Running Technique on Sprint Performance.

Gil, MH, Neiva, HP, Alves, AR, Sousa, AC, Ferraz, R, Marques, MC, and Marinho, DA. The effect of warm-up running technique on sprint performance. J Strength Cond Res 35(12): 3341-3347, 2021-The purpose of the current study was to analyze the effect of changing the running technique during warm-up on sprint performances, running biomechanics, physiological, and psychophysiological responses. Thirty-one physically active men aged 18-23 years (mean ± SD: 19.35 ± 1.08 years of age; 1.77 ± 0.07 m of height; 71.90 ± 10.37 kg of body mass) volunteered to participate and randomly performed 2 maximal 30-m sprints, 5 minutes after completing a warm-up focused on increased stride length-SL (WUL) or a warm-up focused on increased stride frequency-SF (WUF). The results showed that there were no differences between the 30-m sprint performances and in running biomechanics. However, WUF showed increased performances in the first 15 m of the race (WUF: 2.59 ± 0.11 seconds vs. WUL: 2.63 ± 0.15 seconds; p = 0.03), and WUL resulted in higher performances in the last 15 m (1.94 ± 0.19 seconds vs. 1.88 ± 0.09 seconds; p = 0.05). In the second 30-m time trial, WUF also resulted in faster starting 15 m of the race (2.58 ± 0.12 seconds vs. 2.63 ± 0.16 seconds; p = 0.04). Interestingly, the WUF was the warm-up that revealed more stability in performances and running biomechanics between both trials. These results showed that there were no significant differences between warm-ups comprising exercises focusing in higher SL or higher SF in 30-m sprint biomechanics and performance. Nevertheless, different running strategies were caused by those 2 warm-ups and a more stabilized running pattern, and performance values were found when warm-up focused on higher SF.

An investigation on the potential of dedicated exhaust gas recirculation for improving thermal efficiency of stoichiometric and lean spark ignition engine operation

To suppress knock for improving thermal efficiency (ηth) of spark ignition (SI) engines, external exhaust gas recirculation (EGR) has been used. However, the use of EGR reduces flame speed, which leads to observed increase of cycle-to-cycle variations of SI combustion. To overcome this problem by reforming the fuel to add reactive compounds such as H2 and CO to the intake charge, dedicated EGR (D-EGR) concept is proposed, which uses a portion of the cylinders of a multi-cylinder engine to produce the entirety of the EGR consisted mainly of H2 and CO. To maximize the potential of D-EGR and provide new insights for improving ηth of SI engines, this study computationally investigates the use of D-EGR over a wide range of fuel-air equivalence ratios in four-cylinder engine (one D-EGR cylinder and three normal cylinders) for stoichiometric and lean operation. For the computations of laminar burning velocity (SL) and burned gas temperature (Tb), PREMIX in CHEMKIN-PRO were conducted with GRI-Mech 3.0 which is a detailed chemical-kinetic mechanism for methane (CH4).The results show that for D-EGR cylinder, both SL and Tb decrease with an increase of fuel/air equivalence ratios at D-EGR cylinder (ϕD-EGR) because the lower O2 as the more fuel is supplied to D-EGR cylinder for higher ϕD-EGR. ηth at D-EGR cylinder (ηth_D-EGR) decreases from 34.8% to 15.0% with an increase of ϕD-EGR from 1.0 and 3.0, regardless of changes in the amount of gross indicated work (Wg_D-EGR) and heat transferred to the combustion chamber (Qc_D-EGR) at D-EGR cylinder. For stoichiometric combustion at normal cylinder (ϕNormal = 1.0), both SL and Tb increase almost linearly with an increase of ϕD-EGR in the ϕD-EGR = 1.0–2.4 range. Furthermore, ηth at normal cylinder (ηth_Normal) increases from 34.8% to 51.9% between ϕD-EGR = 1.0 and 3.0. As a result, ηth of four-cylinder engine (ηth_Engine) with one D-EGR cylinder and three normal cylinders increases with an increase of ϕD-EGR, and the highest ηth_Engine (39.4%) is achieved for ϕD-EGR = 1.9. For lean combustion at normal cylinder (ϕNormal = 0.9, 0.8, 0.7, 0.6, 0.5), the higher SL and Tb are observed for the higher ϕD-EGR, similar to stoichiometric combustion (ϕNormal = 1.0). Eventually, by a combination of D-EGR addition and lean combustion, the highest ηth_Engine of 42.9% is obtained for ϕNormal = 0.7 with ϕD-EGR of 2.0. This corresponds to a 16.0% increase of ηth_Engine relative to the baseline which is a stoichiometric charge consisted of CH4 and air without any EGR (ηth_Engine = 26.9%).

Buyer–supplier relationship and optimisation model in a dynamic collaborative network with shortages allowed

To remain competitive, enterprises must build and manage product/service customisation and dynamic collaborative networks to respond to market needs in a flexible manner with competitive price and high product/service quality. This study deals with the emerging research problem of optimally dynamic combined decisions: retail price, stock depletion time/service level (SL) and replenishment schedule/quantity in a decentralised two-echelon perishable product collaborative network comprising a single supplier and a single retailer (buyer) over a finite multi-period planning horizon. Analytical solutions are derived using calculus with dynamic programming under two different trading policies, namely retailer-managed inventory with price-only (RMIPO) mode and vendor-managed inventory with consignment contract (VMICC) mode. In both models, shortages are allowed and are fully backlogged. The validity of the proposed approach is demonstrated using the case of a simple supply chain comprising a regional seafood supplier and a local branch store of a national retail chain. The results show that the VMICC policy yields lower retail price, larger replenishment quantity, higher SL and greater channel-wide profit than the RMIPO policy and achieves a win-win situation for both parties in the supply chain. Additionally, consumers benefit from lower retail price and higher SL in the VMICC policy.

Reproductive aging in Japanese quail, Coturnix japonica is associated with changes in central opioid receptors

Quantitative in vitro autoradiography was used to measure specific μ and δ opioid receptor densities in regions of the Japanese quail, Coturnix japonica, brain that regulates reproductive endocrine and behavioral responses to determine the possible involvement of the opioid system in reproductive decline seen during aging. Densities were measured in selected brain regions of young sexually active (YAM), young photoregressed (YPM), old reproductively senescent (OIM) male, young active (YF), and old senescent female (OF) Japanese quail. Medial and lateral septum (SM, SL), medial preoptic area (POM), and n. intercollicularis (ICo) were of particular interest for reproductive responses. Similar to previous observations, μ and δ opioid receptors showed differential distributions in the areas measured. Some age-related changes were observed, with lower SM μ receptor densities in aged males (OIM) than females or young males (YAM). Densities of μ receptors in the POM and in other areas examined did not vary with sex or age. Similarly, OIM males had lower densities of δ receptors in the SM than young males (YAM and YPM); POM δ receptor densities were also low in OIM males compared to the YPM males, and YAM males were intermediate. Interestingly, photoregressed males (YPM) had higher SL δ receptor densities than any other group. Thus there were age-related differences detected in μ receptor densities among groups in the SM of OIM relative to other groups; and the μ and δ receptor densities did not differ in females with brain region. Additionally for δ receptors specifically, YF and OF did not differ from OIM for any brain region and similarly had lower densities of δ receptors compared to YAM males. These data provide support for regional differences in opioid receptor distribution and for age- and sex-related differences in δ opioid receptor densities. The direction of change presents an interesting dichotomy in that, compared to young active males, δ opioid receptor densities increased with loss of reproductive function in the YPM, whereas receptor densities decreased in the OIM. Plasma androgen levels were relatively low in both these groups compared to the young active males. This observation suggests that there is an age-related loss in the ability of this receptor system to respond to circulating and centrally produced steroid hormones in the POM and in some septal regions, compared to young animals that are responding to environmental cues. Furthermore, these data support an active role of the opioid peptide system in the inhibition of the reproductive axis in photoregression.