Sperm environment affects offspring quality in broadcast spawning marine invertebrates

The provisioning of offspring can have far-reaching consequences for later life in a wide range of organisms and generally this provisioning is thought to be under maternal influence or control. In experiments with a broadcast-spawning ascidian, we found that the size of offspring was determined by egg size and the abundance of sperm present during fertilization. Larger eggs were fertilized at low sperm concentrations, whilst smaller eggs were successfully fertilized at high sperm concentrations. These differences in fertilized egg size resulted in differences in the development rate, hatching success and mean size of the subsequent larvae. Our results suggest that, in contrast to females that reproduce by other mating systems, free-spawning mothers lack some control over the provisioning of offspring. Furthermore, because males can alter the sperm environment, they can exert paternal (non-genetic) control over key offspring characteristics.

The effect of hook/bait size and angling technique on the hooking location and the catch of recreationally caught black bream Acanthopagrus butcheri

The black bream Acanthopagrus butcheri recreational fishery is the largest estuarine fishery in Victoria. This fishery is managed through legal-minimum length and daily bag limits. The success of this management strategy requires a high survival rate for released fish. Deep-hooking is known to reduce the chance of fish survival after recreational capture and release. This study investigated the potential to reduce deep-hooking and the number of under-size A. butcheri caught by varying angling gear and techniques. Three sizes of long shank hook (small [size 8], medium [size 4] and large [size 1/0]) and two angling techniques (slack line and tight line) were tested for their deep-hooking rates and selectivity characteristics. Increasing the hook size from small to large decreased the likelihood of deep-hooking by 6.6 times (95% CI 2.3–16.3 times). Fishing with a tight line instead of a slack line decreased the chance of deep-hooking by almost 100% (95% CI 0.8–3.6). Fishing with a large hook instead of a small hook significantly (F = 6.71, df = 2, P = <0.001) increased the mean A. butcheri length, although this mean size increase was less than 1 cm. This study was able to identify angling gear and angling technique manipulations that reduced the rate of deep-hooking when targeting A. butcheri in Victorian estuaries.

Broadcast anti-jamming systems

In a traditional anti-jamming system a transmitter who wants to send a signal to a single receiver spreads the signal power over a wide frequency spectrum with the aim of stopping a jammer from blocking the transmission. In this paper, we consider the case that there are multiple receivers and the transmitter wants to broadcast a message to all receivers such that colluding groups of receivers cannot jam the reception of any other receiver. We propose efficient coding methods that achieve this goal and link this problem to well-known problems in combinatorics. We also link a generalisation of this problem to the Key Distribution Pattern problem studied in combinatorial cryptography

Wireless broadcast encryption based on smart cards

Wireless broadcasting is an efficient way to broadcast data to a large number of users. Some commercial applications of wireless broadcasting, such as satellite pay-TV, desire that only those users who have paid for the service can retrieve broadcast data. This is often achieved by broadcast encryption, which allows a station securely to broadcast data to a dynamically changing set of privileged users through open air. Most existing broadcast encryption schemes can only revoke a pre-specified number of users before system re-setup or require high computation, communication and storage overheads in receivers. In this paper, we propose a new broadcast encryption scheme based on smart cards. In our scheme, smart cards are used to prevent users from leaking secret keys. Additionally, once an illegally cloned smart card is captured, our scheme also allows tracing of the compromised smart card by which illegal smart cards are cloned, and can then revoke all cloned smart cards. The new features of our scheme include minimal computation needs of only a few modular multiplications in the smart card, and the capability to revoke up to any number of users in one revocation. Furthermore, our scheme is secure against both passive and active attacks and has better performance than other schemes.

Screens : television's dispersed 'broadcast'

This chapter focuses on the television-like industries and viewing practices that have emerged on other screens. Through a discussion of the internet and mobile
media, it explores the developing relationships between the existing television
industry, the constellation of new media industries that have integrated video,
and the new audiences generated by these technologies and practices.

Communication and new media : broadcast to narrowcast

Presents a new way of looking at media and mass communication. Traces the history, development and theories of mass communication and the emergence of new media. Looks at questions of ethics, regulation and governance.

Using peoplemap technique to elicit and broadcast sense of place

The population in Geelong Region is expected to keep growing. In order to work towards a better future of the region, it is essential to understand the feelings and needs of local communities and empower them in the community affairs. This study used an innovative technique – peoplemap – to investigate local communities’ sense of place. The primary objective of the investigations was to reveal the sense of place of Geelong Region. Local residents (N=166) in Geelong Region were interviewed face-to-face about how they identify themselves, what they love, what they want, and how empowered they feel. This paper reports the sense of place of three areas of Geelong Region: Ocean Grove, Bannockburn and Teesdale, and Corio-Norlane. Thematic analyses revealed the sense of place of these three areas, and identified their similarities and differences. The results of this study have several implications for government policy makers, planners and designers. This study contributes to the sense of place research, in that civic action was found to be a valid dimension of sense of place.

Effects of bait age, larval chemical cues and nutrient depletion on colonization by forensically important calliphorid and sarcophagid flies

Species colonization patterns on corpses and the frequency of carrion fly oviposition and larviposition are affected by decomposition stage and previous maggot colonization. This study investigated these effects on meat bait colonization by Victorian Diptera of forensic importance. Bait treatments were: 'aged' (aged for 4 days at 22 °C, allowing some decomposition); 'nutrient-depleted' [aged for 4 days at 22 °C with feeding Calliphora vicina (Robineau-Desvoidy) (Diptera: Calliphoridae) larvae]; 'extract' (fresh bait mixed with liquid formed by feeding C. vicina larvae), and 'fresh' (untreated control bait). Statistical analysis (α = 0.05) revealed that colonization frequency differed significantly among treatments (Welch's F 3,18.83 = 4.66, P < 0.05). Post hoc tests showed that fresh and extract baits were colonized extensively throughout the experiment with no significant difference, whereas the colonization of nutrient-depleted baits was significantly lower. This suggests that larval digestive enzymes, larval excreta and cuticular hydrocarbons have less effect on colonizing Diptera than the nutritional content of meat. The colonization of aged baits did not differ significantly from that of fresh, extract or nutrient-depleted baits. A further experiment testing 'very aged' (aged for 8 days at 28 °C), 'larvae-added' (fresh bait with C. vicina larvae added before placement) and 'fresh' (untreated control) baits revealed that very aged baits were colonized significantly less frequently than either fresh or larvae-added baits (Welch's F 2, 6.17 = 17.40, P < 0.05).

Unicast and broadcast throughput maximization in amplify-and-forward relay networks

Cooperative communication (CC) offers an efficient and low-cost way to achieve spatial diversity by forming a virtual antenna array among single-antenna nodes that cooperatively share their antennas. It has been well recognized that the selection of relay nodes plays a critical role in the performance of CC. Most existing relay selection strategies focus on optimizing the outage probability or energy consumption. To fill in the vacancy of research on throughput improvement via CC, we study the relay selection problem with the objective of optimizing the throughput in this paper. For unicast, it is a P problem, and an optimal relay selection algorithm is provided with a correctness proof. For broadcast, we show the challenge of relay selection by proving it nonprobabilistic hard (NP-hard). A greedy heuristic algorithm is proposed to effectively choose a set of relay nodes that maximize the broadcast throughput. Simulation results show that the proposed algorithms can achieve high throughput under various network settings.