814 research outputs found
Citizen journalism and the public sphere : a study of the status of citizen journalism
Gray Whale Distribution and Catch by Alaskan Eskimos: A Replacement for the Bowhead Whale?
The catch of gray whales, Eschrichtius robustus, by Alaskan Eskimos from 1925 to 1980 has been documented to the extent possible by a search of the literature and personal communications with knowledgeable sources. During the period 1950-1980, 47 gray whales were landed by hunters at 12 villages. During this same period, 505 bowhead whales, Balaena mysticetus, were landed at nine coastal whaling villages. Alaskan Eskimos traditionally have been bowhead whalers, principally because of the predictive nature of the bowheads' migration. Gray whaling has never been an important subsistence activity. Because the bowhead population is thought to be depleted, gray whales have been suggested as a possible substitute for subsistence. The distribution of gray whales in Alaskan coastal waters is such that reliable annual whaling for this species is possible only at villages on the shores of the northern Bering Sea; it is unlikely for villages north of Bering Strait to Cape Lisburne, and more unlikely for villages north of Cape Lisburne and east of Point Barrow. Based on cultural and biological grounds, substituting gray whales for bowheads does not appear to be a reliable alternative for the residents of four to six of the nine Eskimo villages that currently participate in bowhead whaling.Key words: gray whale, Eschrichitus robustus; bowhead whale, Balaena mysticetus; Eskimos; subsistence whaling; AlaskaMots clés: baleine grise de Californie, Eschrichtius robustus; balaine boréale, Balaena mysticetus; Esquimaux, chasse à la baleine comme activité de subsistance, Alask
Roadmap to high-energy square pulses in anomalous dispersion fiber lasers
Dissipative soliton resonance (DSR) is a soliton formation where the energy in a dissipative system becomes infinite. In the anomalous dispersion regime, this energy is not limited by the soliton area theorem. Since this phenomenon is wave breaking free, it can be useful in designing fiber lasers generating pulses with relatively high energies. Based on this principle, we have demonstrated the emission of high energetic square pulses from Er:Yb double-clad passively mode-locked fiber lasers using different mode-locking mechanisms. We first show the evolution of pulse width, energy and peak power by varying the pumping power of the amplifier, then we control separately the characteristic of the output square pulse by assigning each one to an amplifier. Experimental results exhibit record energies in fiber lasers up to 10 uJ
Somewhere in Europe (1947): locating Hungary within a shifting geopolitical landscape
Somewhere in Europe/Valahol Európában (Radványi, 1947) was one of the first films made in Hungary after 1945. Financed by the Hungarian Communist Party (MKP), it loudly proclaimed a broad European pertinence in an effort to privilege the universal narrative of childhoods disrupted by the war over narrowly national political concerns. The film’s story of a gang of half-starved children battling for survival in a bombed-out Central European landscape places it squarely within a transnational post-war film-making tradition. Similarities with both Italian neorealism and Soviet socialist realist cinema indicate a shared European experience of the war, but is also attributable to the international training and experience of the film’s personnel. The director Radványi had worked in the Italian industry, while the scriptwriter was the well-known film theorist Béla Balázs, who had worked in Weimar Germany and Soviet Russia. This article argues that in spite of its ostensible commitment to a communist and humanist ideology, the film gives an insight into the Hungarian national obsession with territorial integrity. Hungary’s participation in World War II on the side of the Axis, and its position as a defeated nation under Allied occupation, are seen to complicate the film text. This article contends that in spite its transnational flavour, the film’s focus on lost children wandering a borderless Europe suggests a preoccupation with the country’s uncertain position within a shifting geopolitical landscape. In turn, the film’s official reading by Nemeskürty shows an eagerness to accept the film’s representation of Hungary as a blameless victim of the war, and gives evidence of a need to insert a (false) break between the country’s wartime past as a member of the Axis, and the country’s 1968 present as a member of the Communist world order
Experimental optimization of dissipative soliton resonance square pulses in all anomalous passively mode-locked fiber laser
We investigate experimentally the operational boundaries of dissipative soliton resonance in a double-clad Er:Yb co-doped dual amplifier passively mode-locked figure-of-eight fiber laser. While mode-locking with a nonlinear amplifying loop mirror, we present an exhaustive series of experiments in order to optimize the pulse energy and pulse width tunability. In addition to the pumping power of the amplifiers, several key experimental parameters have been identified such as the net cavity dispersion, the coupling ratio between the two loops of the cavity and the exact position of the long fiber coils. Under optimized conditions, the laser delivers square pulses with an energy varying between 8.5 and 10.1 ÎĽJ while the pulse width ranges from 84-416 ns
Why Making No Difference Makes No Moral Difference
Ascribing moral responsibility in collective action cases is notoriously difficult. After all, if my individual actions make no difference with regard to the prevention of climate change, the alleviation of poverty, or the outcome of national elections, why ought I to stop driving, donate money, or cast my vote? Neither consequentialist nor non-consequentialist moral theories have straightforward responses ready at hand. In this contribution, I present a new suggestion which, based on thoughts about causal overdetermination along the lines of Mackie’s INUS account, aims to show that causally overdetermined collective action cases are morally arbitrary in a way that makes it possible to ascribe moral responsibility even if individual actions make no difference
Broadly peak power and pulse width tunable dissipative soliton resonance generation in Figure-of-Eight fiber laser
We experimentally demonstrate a broadlytunable dissipative soliton resonancedual-amplifier figure-of-eight fiber laseremission.The peak power is tuned continuously from 8.8to 41.4Wby the first amplifier andpulse width from 84 to 416 nsby the second one
10  μJ dissipative soliton resonance square pulse in a dual amplifier figure-of-eight double-clad Er:Yb mode-locked fiber laser
We demonstrate experimentally a double-clad Er:Yb co-doped dual amplifier passive mode-locked figure-of-eight fiber laser that generates high energy, width, and amplitude tunable dissipative soliton resonance square pulses. In our laser system, each loop contains an amplifier that controls a characteristic of the output pulse. The amplitude and width of the output beam can be controlled continuously but, dependently, according to the pump power of each amplifier. The pulse width can be tuned in a range of almost 360Â ns while the peak power varies from 8 to 120Â W. On maximum possible pumping from both sides without having a pulse break, we report square pulses with 10Â ÎĽJ energy per pulse with a signal-to-noise ratio of 60Â dB
Generation of high energy square-wave pulses in all anomalous dispersion Er:Yb passive mode locked fiber ring laser
We have experimentally demonstrated square pulses emission from a co-doped Er:Yb double-clad fiber laser operating in anomalous dispersion DSR regime using the nonlinear polarization evolution technique. Stable mode-locked pulses have a repetition rate of 373 kHz with 2.27 µJ energy per pulse under a pumping power of 30 W in cavity. With the increase of pump power, both the duration and the energy of the output square pulses broaden. The experimental results demonstrate that the passively mode-locked fiber laser operating in the anomalous regime can also realize a high-energy pulse, which is different from the conventional low-energy soliton pulse
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