Topological hypermultiplet on N=2 twisted superspace in four dimensions

We propose a N=2 twisted superspace formalism with a central charge in four dimensions by introducing a Dirac-K\"ahler twist. Using this formalism, we construct a twisted hypermultiplet action and find an explicit form of fermionic scalar, vector and tensor transformations. We construct a off-shell Donaldson-Witten theory coupled to the twisted hypermultiplet. We show that this action possesses N=4 twisted supersymmetry at on-shell level. It turns out that four-dimensional Dirac-K\"ahler twist is equivalent to the Marcus's twist.Comment: 20 pages, no figur

Off-shell Invariant D=N=2 Twisted Super Yang-Mills Theory with a Gauged Central Charge without Constraints

We formulate N=2 twisted super Yang-Mills theory with a gauged central charge by superconnection formalism in two dimensions. We obtain off-shell invariant supermultiplets and actions with and without constraints, which is in contrast with the off-shell invariant D=N=4 super Yang-Mills formulation with unavoidable constraints.Comment: 14 page

Breeding status of Adelie and emperor penguins in the Mt. Riiser-Larsen area, Amundsen Bay

Adelie and emperor penguin colonies were surveyed in the south-western part of the Mt. Riiser-Larsen area, Amundsen Bay (66°47\u27S, 50°33\u27E) on 17 December 1996 by JARE-38. A total of 877 pairs of Adelie penguins were located nesting on a moraine field; most were incubating and some eggs had started hatching. The emperor penguin colony was on a frozen pond in ice-free area. There were 25 adults (including 3 molting birds), 2 immatures and 250 chicks in a creche

Rapid increase in Adelie penguin populations in the Lutzow-Holm Bay area since the mid 1990s

The Adelie penguin, Pygoscelis adeliae, an important component of the Antarctic marine ecosystem, is closely associated with sea ice. Ten breeding populations along the Soya Coast of Lutzow-Holm Bay have been monitored since the 1960s by the Japanese Antarctic Research Expedition and shown to be increasing. In most colonies, small peaks of population increase were observed in the late 1980s with a rapid increase from the mid 1990s. Frequent sea ice break-ups in Lutzow-Holm Bay in the mid 1980s and since the late 1990s are thought to have induced the population increase through increased subadult survival and preferred prey availability. Population monitoring therefore needs to be continued carefully in relation to the environmental changes

Are stomach temperature recorders a useful tool for determining feeding activity?

Despite a number of limitations, stomach temperature recorders are still commonly used to determine feeding activity in free-ranging marine predators. In this regard, it is important to improve the detection rate of these systems by, for instance, increasing the probability that a cold prey touches the sensors. In the present study, we compared the detection rates and mass estimations of water and fish prey ingested by captive king penguins using a two-point temperature recorder (STL) and a single, but large, point recorder (SICUP). Prey items were of different masses (5-45 g) and delivered at different frequencies (high vs. low). Ingestions were recorded as precipitous drop followed by an exponential rise (PDER). Overall, 57.9, 56.0 and 70.0% of the ingestions were detected by the SICUP and the upper and lower sensors of the STL, respectively. Our study confirmed that employing two sensors improves the detection of prey ingestion, but the detection of very small prey items remains insufficient and prey items swallowed at short intervals are detected as cumulative ingestion events. Nonetheless, the total mass of food ingested can be estimated with more than 70% confidence

Population changes of Ad_lie and emperor penguins along the Prince Olav Coast and on the Riiser-Larsen Peninsula

The trends of penguin populations are thought to be reliable indicators of ecosystem changes in the Southern Ocean. There are seven Ad_lie penguin colonies and one emperor penguin colony along the Prince Olav Coast and one emperor penguin colony on the Riiser-Larsen Peninsula. We compiled and analyzed the available data collected by airborne and ground census between 1971 and 2000 in order to determine the breeding status of penguins in this area. Ad_lie penguin populations increased at two colonies; no apparent trends were observed at other colonies. Emperor penguin populations were high in the mid-1990s and suddenly decreased in 2000. Populations need to be carefully monitored in the coming years

Breaking of equipartition in one-dimensional heat-conducting systems

Using information-theoretical methods, we studied how energy equipartition is broken in one-dimensional systems under a heat flow composed of alternating particles of two different masses. The average energy stored in particles of different masses is seen to be different in both ideal gases and harmonic lattices

Diving angle of great cormorants

Seabirds can maximize the relative time spent at depths where prey occur by minimizing the commuting time taken to reach these depths. One way to achieve this goal is to modify dive angle, but there are few measures of dive-angle in free-foraging seabirds. In 2003, we monitored simultaneously the swimming speeds and diving depths of great cormorants (Phalacrocorax carbo) foraging off the Greenland coast, and used these data to reconstruct their descent angle. Both males and females dived on average 12 m. We suggest that birds are able to reduce their descent time for dives beyond this depth by performing pre-dive leaps that allow them to use the momentum of the fall to descend almost vertically and at great speeds. Such pre-dive leaps in shallower dives would be unsuitable because of the proximity of the seabed and the risk of startling prey. Finally, in contrast with deeper divers, descent angles were not steeper when undulations were observed in the depth profile of the previous dive, probably because birds feed on dispersed prey