Some don't like it hot: microhabitat-dependent thermal and water stresses in a trailing edge population

The distributional limits of species in response to environmental change are usually studied at large temporal and/or geographical scales. However, organismal scale habitat variation can be overlooked when investigating large-scale averages of key factors such as temperature. We examine how microhabitat thermal conditions relate to physiological limits, which may contribute to recent range shifts in an intertidal alga. We defined the onset and maximum temperatures of the heat-shock response (HSR) for a southern edge population of Fucus vesiculosus, which has subsequently become extinct. The physiological threshold for resilience (assayed using chlorophyll fluorescence) coincided with declining HSR, determined from the temperature-dependent induction of seven heat-shock protein transcripts. In intertidal habitats, temperature affects physiology directly by controlling body temperature and indirectly through evaporative water loss. We investigated the relationship between the thermal environment and in situ molecular HSR at microhabitat scales. Over cm to m scales, four distinct microhabitats were defined in algal patches (canopy surface, patch edge, subcanopy, submerged channels), revealing distinct thermal and water stress environments during low-tide emersion. The in situ HSR agreed with estimated tissue temperatures in all but one microhabitat. Remarkably, in the most thermally extreme microhabitat (canopy surface), the HSR was essentially absent in desiccated tissue, providing a potential escape from the cellular metabolic costs of thermal stress. Meteorological records, microenvironmental thermal profiles and HSR data indicate that the maximum HSR is approached or exceeded in hydrated tissue during daytime low tides for much of the year. Furthermore, present-day summer seawater temperatures are sufficient to induce HSR during high-tide immersion, preventing recovery and resulting in continuous HSR during daytime low-tide cycles over the entire summer. HSR in the field matched microhabitat temperatures more closely than local seawater or atmospheric data, suggesting that the impacts of climatic change are best understood at the microhabitat scale, particularly in intertidal areas.FCT - Portuguese Science Foundation [POCTI/MAR/61105/2004, EXCL/AAG-GLO/0661/2012, SFRH/BPD/63/03/2009, SFRH/BD/74436/2010]info:eu-repo/semantics/publishedVersio

Orbit targeting specialist function: Level C formulation requirements

A definition of the level C requirements for onboard maneuver targeting software is provided. Included are revisions of the level C software requirements delineated in JSC IN 78-FM-27, Proximity Operations Software; Level C Requirements, dated May 1978. The software supports the terminal phase midcourse (TPM) maneuver, braking and close-in operations as well as supporting computation of the rendezvous corrective combination maneuver (NCC), and the terminal phase initiation (TPI). Specific formulation is contained here for the orbit targeting specialist function including the processing logic, linkage, and data base definitions for all modules. The crew interface with the software is through the keyboard and the ORBIT-TGT display

Empirical corrections to the span load distribution at the tip

An analysis of existing pressure-distribution data was made to determine the variation of the tip loading with wing plan form. A series of empirical tip corrections was derived that may be added to theoretical curves in certain cases to obtain a closer approach to the actual loading at the tip. The analysis indicated that the need for a tip correction decreases as either the aspect ratio or the wing taper is increased. In general, it may be said that, for wings of conventional aspect ratio, corrections to the theoretical span load curves are necessary only if the wing is tapered less than 2:1 and has a blunt tip. If the tip is well rounded in plan form, no correction appears necessary even for a wing with no taper

Pressure-Distribution Measurements on O-2H Airplane in Flight

Results are given of pressure-distribution measurements made over two different horizontal tail surfaces and the right wing cellule, including the slipstream area, of an observation-type biplane. Measurements were also taken of air speed, control-surface positions, control-stick forces, angular velocities, and accelerations during various abrupt maneuvers. These maneuvers consisted of push-downs and pull-ups from level flight, dive pull-outs, and aileron rolls with various thrust conditions. The results from the pressure-distribution measurements over the wing cellule are given on charts showing the variation of individual rib coefficients with wing coefficients; the data from the tail-surface pressure-distribution measurements are given mainly as total loads and moments. These data are supplemented by time histories of the measured quantities and isometric views of the rib pressure distributions occurring in abrupt maneuvers

Span load distribution for tapered wings with partial-span flaps

Tables are given for determining the load distribution of tapered wings with partial-span flaps placed either at the center or at the wing tips. Seventy-two wing-flap combinations, including two aspect ratios, four taper ratios, and nine flap lengths, are included. The distributions for the flapped wing are divided into two parts, one a zero lift distribution due primarily to the flaps and the other an additional lift distribution due to an angle of attack of the wing as a whole. Comparison between theoretical and experimental results for wings indicate that the theory may be used to predict the load distribution with sufficient accuracy for structural purposes

A method of estimating the aerodynamic effects of ordinary and split flaps of airfoils similar to the Clark Y

An empirical method is given for estimating the aerodynamic effect of ordinary and split flaps on airfoils similar to the Clark Y. The method is based on a series of charts that have been derived from an analysis of existing wind-tunnel data. Factors are included by which such variables as flap location, flap span, wing aspect ratio, and wing taper may be taken into account. A series of comparisons indicate that the method would be suitable for use in making preliminary performance calculations and in structural design

Theoretical span loading and moments of tapered wings produced by aileron deflection

The effect of tapered ailerons on linearly tapered wings is theoretically determined. Four different aileron spans are considered for each of three wing aspect ratios and each of four wing taper ratios. The change in lift on one half of the wing, the rolling moment, the additional induced drag, and the yawing moment, due to aileron deflection, are represented by non dimensional coefficients. Similar coefficients are given for the damping and yawing moments, the additional drag, and the change in lift, due to rolling. It was found possible to effect a fairly close agreement between the theoretical and experimental rolling moments by introducing into the theoretical expression for the rolling moment an effective change in angle of attack obtained from an analysis of flap data. The theoretical curves show that the highly tapered wing with long ailerons has a lower ratio of yawing to rolling moment and a lower additional induced drag than wings with less taper