Lower Photo Research Articles

Exploring Coral Reproduction in Great Depth

Photo 1. Great depths at the Gulf of Aqaba and Eilat, Red Sea, host flourishing reefs with thriving communities of corals, fish, and many other animals. The photos here represent scientific explorations of deep coral reefs (termed “mesophotic reefs”) at depth of 80 m (upper photos) using a remotely operated vehicle (ROV) and at depths of 45–60 m using (lower photos), closed-circuit rebreather dives with different gas mixtures as part of a 5-year study, investigating the reproduction of soft corals along with the depth. Photo credits: TASCMAR project (upper photos), Tom Shlesinger (lower photos). Photo 2. The encrusting soft coral Rhytisma fulvum is a common dweller on many Indo-Pacific reefs, and can be found along a large depth gradient of 0–50 m. In the Red Sea, this species usually displays one of two distinct color morphs: yellow colonies dominate the shallow areas (0–25 m) and purple-white colonies dominate the deeper areas (25–50 m). Photo credit: Tom Shlesinger. Photo 3. Between 2016 and 2020, from June–August, we monitored breeding events of the soft coral Rhytisma fulvum to document the exact timing and intensity of reproductive events across the species' entire depth range (i.e., 0–45 m). In the upper panel, Ronen Liberman (who led this study) observes a yellow morph Rhytisma fulvum colony brimming with 1-day old bright yellow embryos, which are entangled on the coral's surface. In the lower panel, Ronen is collecting samples at a mesophotic reef at Eilat, Red Sea, using decompression technical dives. Photo credits: Jessica Bellworthy (upper photo); Tom Shlesinger (lower photo). Photo 4. Within 6 days following fertilization, the embryos develop into elongated larvae-planulae and are ready to detach from the colony's surface to explore the surrounding reef area for a suitable settlement ground. In the upper panel, elongated yellow-colored planulae that are still caught on the surface of its maternal colony. In the lower panel, the white elongated planulae that were released by the purple Rhytisma fulvum colony begin to crawl on the substrate in search of a suitable location for settlement. Photo credit: Tom Shlesinger. These photographs illustrate the article “Soft coral reproductive phenology along a depth gradient: Can “going deeper” provide a viable refuge?” by Ronen Liberman, Tom Shlesinger, Yossi Loya, and Yehuda Benayahu published in Ecology. https://doi.org/10.1002/ecy.3760

Cover Image, Volume 16, Issue 3

Cover Photograph: Cross‐sectional scanning electron micrographs of acicular mullite (upper photo) and aluminum titanate (lower photo) square honeycomb diesel particulate filters investigated in compression and flexure by N.R. Brodnik and K.T. Faber. Acicular mullite has a needle‐like structure linked by a glassy intergranular phase, furnishing mechanical integrity. Aluminum titanate has a heavily microcracked structure due to anisotropic thermal expansion coefficients, providing thermal shock resistance. (Image credit: M. Naviroj and N.R. Brodnik) image

(Invited) Printed Flexible Pressure Sensor Driven by OTFT Array

We have constructed an all printed electronics device manufacturing line and fabricated an organic TFT array on a flexible film substrate. In the automated and continuously operated manufacturing line, we used the reverse offset printer for electrode pattern, digital inkjet printer for organic semiconductor layer, slit-die coater for insulator layer, and gravure offset printer for pixel electrode, specified printer for pressure sensitive layer. The printed pattern with high resolution and high accuracy can be obtained on a flexible film, not only PI, PEN but PET film substrate in low process temperature. The all-printed organic TFT array back-plane is applied to the flexible and light-weight pressure sensor which is driven in active matrix mode. As an example, we demonstrated the compact cylindrical pressure sensor with bare-chip driver ICs at international nanotechnology exhibition in 2018 as shown in lower photo. By taking an advantage of the flexible lightweight and high resolution characteristics of sensors, we are continuing some kinds of field testing in field of healthcare-related applications of rehabilitation and nursing care support and also shelf management system at a convenient store. Furthermore we are challenging the development of robot skin which has sensors as sensitive as human touch. Compact cylindrical pressure sensor demonstrated at international nanotechnology exhibition in 2018. Figure 1

P-1: A Novel Self-Aligned Etch Stopper Structure with Lower Photo Leakage for AMLCD Applications

We introduce a novel self-aligned etch stopper, sidewall-contact a-Si:H TFT (ESSC-TFT) which allow us to reduce the photo leakage current by the island-in structure. This ESSC-TFT design reduces the volume of a-Si film, the active region can totally be shielded by the gate metal resulting in the prevention from direct back light illumination. With the sidewall-contact, the hole current is reduced due to the smaller contact area, and we expect the source, drain parasitic intrinsic resistance of a-Si can be also lessened by the ESSC-TFT structure. Although the defects between etched a-Si and n+ a-Si film may degrade the on current, the ESSC-TFT still exhibits higher on-off ratio than the one in traditional ES-TFT structure.

Effects of in situ experimental shading on the Mediterranean seagrass Posidonia oceanica

The response of the Mediterranean seagrass Posidonia oceanica (L.) Delile to in situ light reduction was examined over a 4 mo period (May to August) in 1993 and 1995. Shoot density, leaf growth rate, shoot size, photosynthetic activity, carbohydrate reserves, epiphyte load and tissue nutrient concentrations were measured in replicated plots under the following light conditions: ambi- ent (36% of surface irradiance (SI) control plots), moderately shaded plots (16.7% SI, MS plots) and severely shaded plots (10.4% SI, SS plots). By the end of the experimental period, all shoots under SS treatments had died, while 70 to 80% had survived under MS treatment; in control plots, shoot den- sities had remained almost constant. Leaf growth rate and biomass decrease with shading were evi- dent 30 d after the beginning of the experiment; shoot density and number of leaves per shoot also fell with shading, but this was apparent only 60 to 90 d after the onset of the shading treatments. Epiphyte load was also considerably reduced by shading. Photosynthetic activity (Pmax) and dark res- piration rates (R) of control plants showed a characteristic increase from spring (May) to the end of summer (August), resulting in higher saturation (Isat) and compensation (Ic) points and lower photo- synthetic efficiencies (α ) at the end of the experimental period; however, photosynthetic parameters in shaded plants (MS treatment) first increased (as in control plots) from May to June, but decreased afterwards (from June to August), indicating photoacclimation of P. oceanica to low light conditions. Shading depressed carbohydrate storage in the rhizomes of shaded plants, in which starch concen- trations were quickly reduced to 60% of those of control plants. The leaves of shaded shoots showed a significant increase in nutrient (specially nitrogen) concentrations. This was probably due to translocation from shed leaves and also to low utilisation rates for growth. We infer that minimum light requirements of P. oceanica are between 16 and 10%, of surface irradiance, values which are consistent with light availability at the deep limits of nearby meadows. One year after shades had been removed, shoot densities remained unchanged (relative to the moment of screen removal), indi- cating both the absence of cascading effects and a very low recovery capacity of this seagrass.

Solar Magnetic Field Studies Using the 12 Micron Emission Lines. III. Simultaneous Measurements at 12 and 1.6 Microns

We report total magnetic —eld strength measurements made simultaneously at two heights in the solar atmosphere using two infrared lines: the upper photospheric 12.32 km line of Mg I and the lower photo- spheric 1.56 km line of Fe I. We used the dual outputs of the McMath-Pierce Fourier transform spectro- meter to obtain high spectral resolution data for both lines using a single input aperture, eliminating spatial registration errors. The results show a decrease of —eld strength with height in sunspots and plages, demonstrating —eld divergence between the lower and upper photosphere. Sunspot penumbral —eld strengths decrease by 12% between the two heights, while plages show decreases as large as a factor of 3. The plage results are consistent with thin¨—ux-tube models, provided that merging of —ux tubes occurs. However, the sunspot results imply height gradients in total —eld strength that are large (2 G km~1) at the inner edge of the penumbra and decrease to smaller values (0.5 G km~1) at the outer penumbral edge. The magnitude of these gradients and their radial variation imply that sunspots do not conform to the ii similarity assumption ˇˇ commonly invoked in classic analytic models of sunspot magne- tostatic structure. Subject headings: Sun: infraredSun: magnetic —eldssunspots

Luminescence of an alternated thiophene-3-alkylthiophene copolymer

The electro-optical properties of a novel alternated copolymer constituted by thiophene and 3-octylthiophene monomer are presented. The comparison with a poly(3-octylthiophene) indicates that the copolymer has a higher conjugation path but a lower photo- and electro-luminescence efficiency. Luminescence quenching effects due to shorter interchain distances in the copolymer may possibly account for this behavior.

Electronic and Optical Properties of A—(Si, Ge):H Alloys

AbstractWe describe the preparation and electronic and optical properties of amorphous (Si, Ge) alloys. A—(Si, Ge):H alloys were prepared by glow discharge decomposition of SiH4 and GeH4. The bandgap was varied between 1.78 and 1.42 eV by changing the GeH4:SiH4 ratio in the gas phase. We find a distinct influence of growth temperature on electronic properties. Films grown at low temperatures (200–250C) tendto have much lower photo conductivity than films grown at higher temperatures (300–325C). The electron (μ τ) products of high temperature films are general> 1X10–7 cm2/V. We also obtain very sharp valence band tails in a—(Si, Ge):H alloys, with slopes of ∼ 40 meV. The hole (μ τ) product is generally ∼1–2X10–8 cm2/V. All these properties suffer a catastrophic decline when bandgap is reduced below about 1.5 eV.

Corrections

September, page 90—The citation by the President upon awarding Charles H. Townes the National Medal of Science should read: “For fundamental contributions to the understanding of matter through its interaction with electromagnetic radiations and the application of this knowledge to the service of mankind, most notably in the invention of the maser and laser.” November, page 122—The letter “From Nuke to Anti-Nuke” was written by Thornton Page of the NASA Johnson Space Center, not Thomas Page. January, page 25—The illustrations were reversed. The crystalline pattern is in the lower photo, and the sheared fluid is in the upper photo.