Biodiversity in eastern Mediterranean marine aquaculture: an approach to new species.

Aquaculture is an important agro-food activity to ensure the amount of EPA and DHA indicated by WOS for human health, on the top of precious proteins. In spite that in the Mediterranean area only few marine species (sea bass and sea bream) cover the 92.4% of the market, an increased biodiversity in the production would improve the nutritional quality, as well as the resource for the market and the possibility to better exploit natural resources. This research work is focused on the evaluation of biological and physiological functions of new species, such as rabbitfish (Siganus rivulatus) and common pandora (Pagellus erythrinus), in respect to their capacity for aquaculture production. Morphometric measurements on wild rabbitfish revealed that the TL-TW relationship is described by the equation y=0.068x+11.044. Condition factor (K) was 1.65\ub10.17, HSI was 1.4\ub10.4 and GSI was found to reach maximum values near the full moon during summer months. Respirometry on individual cultured rabbitfish was measured at 17, 20, 23 and 26\ub0C. Oxygen consumption rate increased with water temperature and it was varied between 2.4 710-3 mg O2/g BW/min at 17\ub0C and 1.1 710-2 mg O2/g BW/min at 26\ub0C. Hypoxia-inducible factor-1a, which responds to changes in available oxygen in the cellular environment, was identified in brain and liver samples. Growth experiment on rabbitfish that lasted for 1 year and tested two feeds with different protein content, 35 and 44%, showed no significant difference between the two treatments. Experiment on the effect of vitamin C and astaxanthin on the reproduction performance and quality of eggs and larvae in common pandora, showed that vitamin C improves the reproductive capacity of broodstock and the quality of offsprings

Information-centric communication in mobile and wireless networks

Information-centric networking (ICN) is a new communication paradigm that has been proposed to cope with drawbacks of host-based communication protocols, namely scalability and security. In this thesis, we base our work on Named Data Networking (NDN), which is a popular ICN architecture, and investigate NDN in the context of wireless and mobile ad hoc networks. In a first part, we focus on NDN efficiency (and potential improvements) in wireless environments by investigating NDN in wireless one-hop communication, i.e., without any routing protocols. A basic requirement to initiate informationcentric communication is the knowledge of existing and available content names. Therefore, we develop three opportunistic content discovery algorithms and evaluate them in diverse scenarios for different node densities and content distributions. After content names are known, requesters can retrieve content opportunistically from any neighbor node that provides the content. However, in case of short contact times to content sources, content retrieval may be disrupted. Therefore, we develop a requester application that keeps meta information of disrupted content retrievals and enables resume operations when a new content source has been found. Besides message efficiency, we also evaluate power consumption of information-centric broadcast and unicast communication. Based on our findings, we develop two mechanisms to increase efficiency of information-centric wireless one-hop communication. The first approach called Dynamic Unicast (DU) avoids broadcast communication whenever possible since broadcast transmissions result in more duplicate Data transmissions, lower data rates and higher energy consumption on mobile nodes, which are not interested in overheard Data, compared to unicast communication. Hence, DU uses broadcast communication only until a content source has been found and then retrieves content directly via unicast from the same source. The second approach called RC-NDN targets efficiency of wireless broadcast communication by reducing the number of duplicate Data transmissions. In particular, RC-NDN is a Data encoding scheme for content sources that increases diversity in wireless broadcast transmissions such that multiple concurrent requesters can profit from each others’ (overheard) message transmissions. If requesters and content sources are not in one-hop distance to each other, requests need to be forwarded via multi-hop routing. Therefore, in a second part of this thesis, we investigate information-centric wireless multi-hop communication. First, we consider multi-hop broadcast communication in the context of rather static community networks. We introduce the concept of preferred forwarders, which relay Interest messages slightly faster than non-preferred forwarders to reduce redundant duplicate message transmissions. While this approach works well in static networks, the performance may degrade in mobile networks if preferred forwarders may regularly move away. Thus, to enable routing in mobile ad hoc networks, we extend DU for multi-hop communication. Compared to one-hop communication, multi-hop DU requires efficient path update mechanisms (since multi-hop paths may expire quickly) and new forwarding strategies to maintain NDN benefits (request aggregation and caching) such that only a few messages need to be transmitted over the entire end-to-end path even in case of multiple concurrent requesters. To perform quick retransmission in case of collisions or other transmission errors, we implement and evaluate retransmission timers from related work and compare them to CCNTimer, which is a new algorithm that enables shorter content retrieval times in information-centric wireless multi-hop communication. Yet, in case of intermittent connectivity between requesters and content sources, multi-hop routing protocols may not work because they require continuous end-to-end paths. Therefore, we present agent-based content retrieval (ACR) for delay-tolerant networks. In ACR, requester nodes can delegate content retrieval to mobile agent nodes, which move closer to content sources, can retrieve content and return it to requesters. Thus, ACR exploits the mobility of agent nodes to retrieve content from remote locations. To enable delay-tolerant communication via agents, retrieved content needs to be stored persistently such that requesters can verify its authenticity via original publisher signatures. To achieve this, we develop a persistent caching concept that maintains received popular content in repositories and deletes unpopular content if free space is required. Since our persistent caching concept can complement regular short-term caching in the content store, it can also be used for network caching to store popular delay-tolerant content at edge routers (to reduce network traffic and improve network performance) while real-time traffic can still be maintained and served from the content store

Biodiversity in eastern Mediterranean marine aquaculture: an approach to new species.

Aquaculture is an important agro-food activity to ensure the amount of EPA and DHA indicated by WOS for human health, on the top of precious proteins. In spite that in the Mediterranean area only few marine species (sea bass and sea bream) cover the 92.4% of the market, an increased biodiversity in the production would improve the nutritional quality, as well as the resource for the market and the possibility to better exploit natural resources. This research work is focused on the evaluation of biological and physiological functions of new species, such as rabbitfish (Siganus rivulatus) and common pandora (Pagellus erythrinus), in respect to their capacity for aquaculture production. Morphometric measurements on wild rabbitfish revealed that the TL-TW relationship is described by the equation y=0.068x+11.044. Condition factor (K) was 1.65±0.17, HSI was 1.4±0.4 and GSI was found to reach maximum values near the full moon during summer months. Respirometry on individual cultured rabbitfish was measured at 17, 20, 23 and 26°C. Oxygen consumption rate increased with water temperature and it was varied between 2.4×10-3 mg O2/g BW/min at 17°C and 1.1×10-2 mg O2/g BW/min at 26°C. Hypoxia-inducible factor-1a, which responds to changes in available oxygen in the cellular environment, was identified in brain and liver samples. Growth experiment on rabbitfish that lasted for 1 year and tested two feeds with different protein content, 35 and 44%, showed no significant difference between the two treatments. Experiment on the effect of vitamin C and astaxanthin on the reproduction performance and quality of eggs and larvae in common pandora, showed that vitamin C improves the reproductive capacity of broodstock and the quality of offsprings

First report of Antigastra catalaunalis on sesame in Greece.

In August 2016, severe infestations of sesame crops by the sesame leaf webber and capsule borer, Antigastra catalaunalis (Duponchel) (Lepidoptera: Crambidae), were recorded in rural areas of the Regional Unit of Drama, Northern Greece. Larval feeding-damage symptoms were observed on leaves and capsules. Infestations were recorded in all of the inspected sesame fields. The infestation levels were considerable high resulting in significant economic loss. To our knowledge, this is the first report of A. catalaunalis severe infestation on sesame in Greece

Integration strategies of cortical neurons in the early postnatal neocortex

Over the course of the first three postnatal weeks the cells of the neocortex undergo considerable maturation. My aim was to track some of the changes that occur, to create a detailed electrophysiological study of the postnatal neocortex. This would allow me to better understand the developmental journeys taken by discrete neuronal populations within the maturing network. To this end, I used glutamate uncaging and whole-cell patch-clamp electrophysiology to record from neocortical pyramidal cells and Nkx2-1 derived interneurons located in different cortical layers and regions of the cortex between postnatal days (P) 5-21. In so doing I was able to track the maturation of their intrinsic electrophysiology and synaptic connectivity. The electrophysiological properties of cortical neurons develop markedly over the course of development and there is a gradual emergence of distinct electrophysiological firing types amongst both pyramidal cells and interneurons. In terms of their synaptic inputs pyramidal neurons and interneurons possess unique methods of synaptic integration. Pyramidal neurons show a stereotyped pattern of input maturation, whereby there is a gradual emergence of the mature, canonical pattern of input. This is predicted by translaminar, NMDA receptor mediated inputs at early ages, that likely act as the substrate for the formation of mature AMPA receptor containing synapses. In contrast Nkx2-1 derived interneurons showed no shift in laminar input organization over the course of development, with prominent inputs observed from the earliest ages of the study. However, there seems to be a significant degree of heterogeneity in the organization of these inputs and I provide some insight into this variation. Taken together these findings provide a picture of the connectivity of the early network and using these data I am able to produce a final hypothesis, which shows how interneurons and pyramidal cells may interact to produce the canonical pattern of cortical connectivity

An Analysis of the Essential Chromatin Factor Zinc Finger Protein 1 (ZFP-1), and a Study of the Involvement of RNAi factors in Histone Processing in Caenorabditis Elegans

The formation of chromatin defines when and where genes will be expressed, from the histone proteins forming the nucleosome and their many post-translational modifications, to the immense number of proteins that bind these modifications. This thesis is comprised of two projects: the first is an analysis of the essential plant homeodomain-containing protein called zinc finger protein 1 (ZFP-1); the second is a study into how RNA interference (RNAi) factors are involved in histone production in C. elegans. I investigate the physical and biological properties of the PHD fingers of ZFP-1 and find that 1) they are essential for viability and 2) they specifically bind to methylated lysine 4 on histone H3. This study has expanded our understanding of the molecular nature of ZFP-1, the C. elegans ortholog of AF10, which has a role in chromosomal translocations promoting leukemia. I also determine that the RNAi factors CSR-1, EGO-1 and DRH-3 are required for proper histone production in C. elegans. Severe histone depletion results from the knockdown of these RNAi pathway components, which explains both the phenotypes of sterility and chromosome segregation defects in early embryos that are associated with mutants of these factors. This discovery explains the well-known, but poorly understood, phenotypes of the RNAi mutants and provides the first evidence for RNAi positively affecting gene expression