Development of a method to identify foot strike on an arena surface: application to jump landing

Foot strike can be difficult to determine using kinematics alone, particularly when studying equine activities on more compliant surfaces, so this study was done with the aim of developing and validating a method to determine foot strike on an arena surface that can be used in conjunction with kinematics alone, and of applying the method in the context of measuring foot strike during jump landing on an arena surface. A low-cost contact mat was developed. The timing of the contact mat switching ‘on’ was compared to the timing of a force platform onset of 20 N, load and loading rate at foot strike. Two groups of 25 participants were used in two separate studies to validate the contact mat: the first measured the difference in timing with respect to two different activities (running and stepping down from a box), and the second measured the difference in timing with respect to 1- and 2-cm depths of an arena surface during running. In a third study, the mat was used to measure leading limb foot strike of six horses during jump landing, and these data were compared to kinematics from a palmar marker on the hoof wall. All data were recorded at 500 Hz. A consistent difference in delay was found between the mat and force platform onset, and as a result, no significant differences (P>0.05) in timing delay between different loading rates or depths were found. During jump landing, foot strike (determined from the mat) occurred after the vertical velocity minima and the acceleration maxima for the hoof marker, but it occurred before the point where the rate of vertical displacement began to reduce. In conclusion, further work is needed to enhance these techniques, but these preliminary results indicate that this method may be effective in determining foot strike for field-based applications

Deep Inelastic Scattering and Gauge/String Duality

We study deep inelastic scattering in gauge theories which have dual string descriptions. As a function of $gN$ we find a transition. For small $gN$, the dominant operators in the OPE are the usual ones, of approximate twist two, corresponding to scattering from weakly interacting partons. For large $gN$, double-trace operators dominate, corresponding to scattering from entire hadrons (either the original `valence' hadron or part of a hadron cloud.) At large $gN$ we calculate the structure functions. As a function of Bjorken $x$ there are three regimes: $x$ of order one, where the scattering produces only supergravity states; $x$ small, where excited strings are produced; and, $x$ exponentially small, where the excited strings are comparable in size to the AdS space. The last regime requires in principle a full string calculation in curved spacetime, but the effect of string growth can be simply obtained from the world-sheet renormalization group.Comment: 52 pages, 10 figure

The limits of transnational solidarity : the Congress of South African Trade Unions and the Swaziland and Zimbabwean crises

The Congress of South African Trade Unions (COSATU), the main union federation in South Africa, was instrumental in ending apartheid. This paper evaluates COSATU's post-apartheid role in working for democracy elsewhere in Southern Africa through deepening transnational solidarity, focusing on its role in Zimbabwe and Swaziland. Although the federation successfully mobilised trade union members to oppose the contravention of human and labor rights, its ability to affect lasting change was limited by contradictory messages and actions by the South African government, the dualistic nature of institutional formation in these countries, strategic miscalculations and structural limitations on union power

The 2004 and 2005 Sumatra Earthquakes: Implications for the Lisbon earthquake

The Sumatra mega-earthquake of 26 December 2004 (Mw=9.3) was the strongest earthquake in the world since the 1964 Alaska earthquake and the fifth strongest since 1900. The earthquake occurred at the interface of the India and Burma plates and triggered a massive tsunami that affected several countries throughout South and Southeast Asia. Three months later, on 28 March 2005, about 200 km south of this event but at a greater depth (28 km), occurred a magnitude 8.7 earthquake. This event was probably triggered by stress variations caused by the December mega-earthquake. In this work we describe the rupture process of both earthquakes, estimated from teleseismic broad-band waveform data provided by IRIS-DMC stations. The rupture direction and velocity were determined from common pulse durations observed in P waveforms using DIRDOP computational code (DIRectivity DOPpler effect). The modified Kikuchi and Kanamori method has been used to determine the slip distribution. For the mega- earthquake two segments of 150 km width (along dip) and 990 km total length with different azimuth were estimated, based on the subduction geometry, aftershock distribution and CMT. Results show that the rupture spread mainly to the North with an average velocity of 2.7 km/s. The focal mechanism shows thrust motion on a plane oriented in a NNW-SSE direction and a horizontal pressure axis in the NNE-SSW direction. The fault slip distribution shows the following pattern: 1) the rupture nucleated at the hypocenter as a circular crack breaking a shallow asperity of about 60 km radius during the first 60 sec; 2) after the initial break to the NNW, the rupture propagated during ~180 s and broke a middle large asperity centred at about 360 km from the epicentre; 3) finally, the rupture propagated further to the north and broke a third asperity centred at ~840 km from the epicentre during at least 110 sec. The maximum slip reaches 14 m in the central asperity and the total seismic moment is Mo=3.0x1022 Nm (Mw=8.9), which is less than the value given by the ESMC and USGS (the loss of seismic scalar moment was released in a third segment located to the north). The total source duration and rupture length are estimated to be above 350 sec and 990 km, respectively. For the earthquake of 28 March 2005, a rectangular rupture plane with 400 km length (along the strike direction) and 125 km width (along the dip direction) was obtained from the subduction geometry, aftershock distribution and CMT. Results show that the rupture spread during about 110s in the southwest direction with an average velocity of ~3.3 km/s. Most of the seismic moment was released at the break of two asperities: the largest one located at about 90km from the hypocenter, and the other one at 175 km from the hypocenter. These two asperities correspond on the surface to the areas most affected by the event (Nias Island). The maximum slip reaches 11.5 m in the largest asperity and the total seismic moment is Mo=0.82x1022 Nm (Mw=8.6). The focal mechanism shows thrust motion similar to this shown by the mega-earthquake. Probably, the 1755 Lisbon earthquake (Mw∼9.0) released as much or more energy as any seismic event of recorded history prior to 2004 December. Nevertheless, the location of the source, responsible for the Lisbon tsunami, is not well known; the epicentres suggested by various authors are separated by some hundreds of km. We compare the similarities and differences of these two mega- earthquakes (Sumatra and Lisbon) with the purpose of reducing the uncertainties relative to the location of the seismogenic zone responsible for the 1755 Lisbon earthquake. Lessons learned from the Sumatra earthquake, through scientific studies, should help to reduce the number of victims and damage during future earthquakes in Portugal

Breaking New Ground: Pension Fund Bargaining at Eastern

[Excerpt] Traditionally, unions have exercised their economic power through the strike and the boycott to gain collective bargaining agreements and through the day-to-day enforcement of contract provisions. But the rapidly growing mobility of capital and the increased rate of introducing new technologies have increasingly neutralized the effectiveness of labor\u27s fundamental tools. Thus, it is crucial that unions begin to develop new tools to enhance the economic power of workers. This means that labor must redefine its role with respect to the economy and to the process of allocating resources in the society. Increasingly, unions are demanding plant closing protections, a voice in the introduction of new technologies, restrictions on subcontracting, commitments for reinvestment in existing facilities, and job security for current workers

The making of a new working class? A study of collective actions of migrant workers in South China

In this study, we argue that the specific process of the proletarianization of Chinese migrant workers contributes to the recent rise of labour protests. Most of the collective actions involve workers' conflict with management at the point of production, while simultaneously entailing labour organizing in dormitories and communities. The type of living space, including workers' dormitories and migrant communities, facilitates collective actions organized not only on bases of locality, ethnicity, gender and peer alliance in a single workplace, but also on attempts to nurture workers' solidarity in a broader sense of a labour oppositional force moving beyond exclusive networks and ties, sometimes even involving cross-factory strike tactics. These collective actions are mostly interest-based, accompanied by a strong anti-foreign capital sentiment and a discourse of workers' rights. By providing detailed cases of workers' strikes in 2004 and 2007, we suggest that the making of a new working class is increasingly conscious of and participating in interest-based or class-oriented labour protests

Breathers and kinks in a simulated crystal experiment

We develop a simple 1D model for the scattering of an incoming particle hitting the surface of mica crystal, the transmission of energy through the crystal by a localized mode, and the ejection of atom(s) at the incident or distant face. This is the first attempt to model the experiment described in Russell and Eilbeck in 2007 (EPL, v. 78, 10004). Although very basic, the model shows many interesting features, for example a complicated energy dependent transition between breather modes and a kink mode, and multiple ejections at both incoming and distant surfaces. In addition, the effect of a heavier surface layer is modelled, which can lead to internal reflections of breathers or kinks at the crystal surface.Comment: 15 pages, 12 figures, based on a talk given at the conference "Localized Excitations in Nonlinear Complex Systems (LENCOS)", Sevilla (Spain) July 14-17, 200

Alt-Bargaining

Reflections on the modern labor movement tend to take a bad-news/good-news approach to the future: yes, unions are down, but a new trend suggests they are far from out. The framing is optimistic, but also right. What’s “new” has often involved innovations in unionizing, and over the past three decades organized labor has gotten creative, taken risks, and every once in a while—for the first time in a while—started winning. The new wave campaigns were variously “comprehensive,” legally canny, sometimes global, and usually movement-esque in their approach to traditionally underrepresented constituencies and sectors. Less discussed is that the trends developed counterparts: hot takes in unionization became new normals in negotiation. If exposing dirty directors weakened corporate resolve in union drives, C-suite exposés became a regular feature in contract drives. If union organizers learned that an employer’s fiercest anti-union weapons could be traded away during a campaign, contract organizers realized that a collective bargaining agreement could do the same for future campaigns. And if fighting for a union became less about money and more about morality, so did fighting for a contract. The current trend is “alt,” short for “alternative-labor,” and invoked where unions or non-profits mobilize workers for better working conditions but not necessarily collective bargaining. As its name implies, the efforts have varied origins, tactics, and aims, making the category hard to define with specificity. But if the alt-labor innovations of today signal how more mature entities—alt-, traditional, or otherwise—will push for workplace benefits tomorrow, clarifying what the present advance is, exactly, is useful foreshadowing. That definitional project is one goal of this article. Alt-labor is incredibly diverse, but through-lines exist. Its constituent groups are repeatedly marked by three non-standard relationships to law that generate exceptional conceptions of group membership, challenge organizing’s presumptive outer-bounds, and prove how even bad organizing doctrine can be harnessed for good. The major goal, though, is to argue that alt-labor isn’t foreshadowing anything because alt-bargaining is here. Over and over, the unconventional legal orientations that facilitate alt-labor’s inclusive approaches to membership, fluid conceptions of which workers or what entities are organizable, and optimistic spins on employment rights can be spotted in recent campaigns where the activists are already assembled and scrutiny instead surrounds how the group is negotiating. The innovative legal perspectives that make up alternative organizing practices, in other words, can now be found in situations where labor and management are actually passing proposals