Effects of global warming on animal distribution and performance become visible in many marine ecosystems. The present study was designed to develop a concept for a cause and effect understanding with respect to temperature changes and to explain ecological findings based on physiological processes. The concept is based on a wide comparison of invertebrate and fish species with a special focus on recent data obtained in two model species of fish. These fish species are both characterized by northern and southern distribution limits in the North Atlantic: eelpout (Zoarces viviparus), as a typical non-migrating inhabitant of the coastal zone and the cod (Gadus morhua), as a typical inhabitant of the continental shelf with a high importance for fisheries.Mathematical modelling demonstrates a clear significant correlation between climate induced temperature fluctuations and the recruitment of cod stocks. Growth performance in cod is optimal at temperatures close to 101C, regardless of the population investigated in a latitudinal cline. However, temperature specific growth rates decrease at higher latitudes. Also, fecundity is less in White Sea than in North and Baltic Sea cod or eelpout populations. These findings suggest that a cold-induced shift in energy budget occurs which is unfavorable for growth performance and fecundity. Thermal tolerance limits shift depending on latitude and are characterized by oxygen limitation at both low or high temperatures. Oxygen supply to tissues is optimized at low temperature by a shift in hemoglobin isoforms and oxygen binding properties to lower affinities and higher unloading potential. Protective stimulation of heat shock protein synthesis was not observed.According to a recent model of thermal tolerance the downward shift of tolerance limits during cold adaptation is associated with rising mitochondrial densities and, thus, aerobic capacity and performance in the cold, especially in eurythermal species. At the same time the costs of mitochondrial maintenance reflected by mitochondrial proton leakage should rise leaving a lower energy fraction for growth and reproduction. The preliminary conclusion can be drawn that warming will cause a northern shift of distribution limits for both species with a rise in growth performance and fecundity larger than expected from the Q 10 effect in the north and lower growth or even extinction of the species in the south. Such a shift may heavily affect fishing activities in the North Sea. r
We report for the first time the demonstration of 3D integrated circuits obtained by die-to-die stacking using Cu Through Silicon Vias (TSV). The Cu TSV process is inserted between contact and M1 of our reference 0.13µm CMOS process on 200mm wafers. The top die is thinned down to 25µm and bonded to the landing wafer by Cu-Cu thermo-compression. Both top and landing wafers contain CMOS finished at M2 to evaluate the process impact both FEOL and BEOL. The results confirm no degradation of the FEOL performance. The functionality of various ring oscillator topologies that include inverters distributed over both top and bottom dies connected through TSVs demonstrates excellent chip integrity after the TSV and 3D stacking process. 3D-SIC processRecently 3D integration has gained a lot of interest due to its potential to alleviate some important performance limitations facing CMOS scaling and because it enables so-called heterogeneous integration [1][2]. Different approaches to 3D integration are reported depending on system level requirements [3]. Our 3D Stacked IC (3D-SIC) process [4][5] uses IC foundry infrastructure to create Through Silicon Vias (TSVs) prior to BEOL processing. The main advantage of this approach is the fact that it has minimal impact on both FEOL and BEOL design and processing. Furthermore it offers very high TSV densities. The TSV process sequence is summarized in Fig. 1. Figure 1: Schematic of the 3D-SIC Through Silicon Via (TSV) module.After processing of the CMOS FEOL and the PMD stack, we patterned TSVs with a diameter of 5µm and a pitch of 10µm using a 3µm thick I-line resist. We performed an undercut free, resist-based TSV etch (Fig. 2); undercut underneath the contact layer is avoided by pre-deposition of a polymer on the sidewall of the etched PMD/STI stack prior to the Si etch. For electrical isolation, we deposit a 100nm SACVD O 3 -TEOS layer. The metallization sequence consists of applying a 80nm PVD Ta barrier and a 300nm PVD Cu seed followed by an ECD via fill using a 3-component plating chemistry. Finally the Cu overburden is polished in a top-side TSV CMP step (Fig. 3). After this process, we apply a standard, 2 metal layer BEOL process to finalize the top Si-die. Figure 2&3: FIB through TSV in vicinity of device after etch, strip& clean (left), and after TSV CMP and sintering (right). (Pt on top for contrast).After wafer test, the wafer is mounted on a temporary carrier and thinned down to a Si-thickness of ~25 m by a combination of grinding and CMP. In this process, the TSVs are exposed on the wafer backside. Next the Si is recessed by dry etching over a distance of ~700nm with respect to the copper TSV. In this work the dies were then stacked by Cu-Cu thermo-compression bonding in a Die-to-Die (D2D) fashion, although compatibility with Die-to-Wafer integration remains. Figure 4 shows an optical 3D reconstruction of the obtained 3D stack. Figure 4: Optical 3D reconstruction based on multiple images at different height of thinned top die stacked to a bottom die by Cu-Cu bonding.
The effects of increased endogenous cortisol levels were compared with those of sublethal copper exposure in the freshwater common carp, Cyprinus carpio. Fish were exposed to either increased levels of endogenous cortisol (200 ng/ml) or sublethal copper (1.9 microM) alone or were pretreated by elevating plasma cortisol levels prior to copper exposure to assess whether interactions between both treatments occurred. Effects induced by increased cortisol levels included increased Na+/K(+)-adenosine triphosphate (ATPase) activity and increased plasma Na+ and plasma osmolarity, while copper exposure induced anaerobic metabolism, gill damage, decreasing Na+/K(+)-ATPase activity, decreasing plasma ion levels, and blood thickening. Pretreatment of copper-exposed fish with cortisol partially protected these fish by reducing the copper-induced decrease in Na+/K(+)-ATPase activity. Overall, the results obtained in this study argue against a major role for cortisol as an intermediate for the toxic effects of copper.
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